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1 /*#define CHASE_CHAIN*/
2 /*
3  * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
4  *	The Regents of the University of California.  All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that: (1) source code distributions
8  * retain the above copyright notice and this paragraph in its entirety, (2)
9  * distributions including binary code include the above copyright notice and
10  * this paragraph in its entirety in the documentation or other materials
11  * provided with the distribution, and (3) all advertising materials mentioning
12  * features or use of this software display the following acknowledgement:
13  * ``This product includes software developed by the University of California,
14  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
15  * the University nor the names of its contributors may be used to endorse
16  * or promote products derived from this software without specific prior
17  * written permission.
18  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21  */
22 
23 #ifdef HAVE_CONFIG_H
24 #include "config.h"
25 #endif
26 
27 #ifdef _WIN32
28 #include <pcap-stdinc.h>
29 #else /* _WIN32 */
30 #if HAVE_INTTYPES_H
31 #include <inttypes.h>
32 #elif HAVE_STDINT_H
33 #include <stdint.h>
34 #endif
35 #ifdef HAVE_SYS_BITYPES_H
36 #include <sys/bitypes.h>
37 #endif
38 #include <sys/types.h>
39 #include <sys/socket.h>
40 #endif /* _WIN32 */
41 
42 #ifndef _WIN32
43 
44 #ifdef __NetBSD__
45 #include <sys/param.h>
46 #endif
47 
48 #include <netinet/in.h>
49 #include <arpa/inet.h>
50 
51 #endif /* _WIN32 */
52 
53 #include <stdlib.h>
54 #include <string.h>
55 #include <memory.h>
56 #include <setjmp.h>
57 #include <stdarg.h>
58 
59 #ifdef MSDOS
60 #include "pcap-dos.h"
61 #endif
62 
63 #include "pcap-int.h"
64 
65 #include "ethertype.h"
66 #include "nlpid.h"
67 #include "llc.h"
68 #include "gencode.h"
69 #include "ieee80211.h"
70 #include "atmuni31.h"
71 #include "sunatmpos.h"
72 #include "ppp.h"
73 #include "pcap/sll.h"
74 #include "pcap/ipnet.h"
75 #include "arcnet.h"
76 
77 #include "grammar.h"
78 #include "scanner.h"
79 
80 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
81 #include <linux/types.h>
82 #include <linux/if_packet.h>
83 #include <linux/filter.h>
84 #endif
85 
86 #ifdef HAVE_NET_PFVAR_H
87 #include <sys/socket.h>
88 #include <net/if.h>
89 #include <net/pfvar.h>
90 #include <net/if_pflog.h>
91 #endif
92 
93 #ifndef offsetof
94 #define offsetof(s, e) ((size_t)&((s *)0)->e)
95 #endif
96 
97 #ifdef INET6
98 #ifdef _WIN32
99 #if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
100 /* IPv6 address */
101 struct in6_addr
102   {
103     union
104       {
105 	u_int8_t		u6_addr8[16];
106 	u_int16_t	u6_addr16[8];
107 	u_int32_t	u6_addr32[4];
108       } in6_u;
109 #define s6_addr			in6_u.u6_addr8
110 #define s6_addr16		in6_u.u6_addr16
111 #define s6_addr32		in6_u.u6_addr32
112 #define s6_addr64		in6_u.u6_addr64
113   };
114 
115 typedef unsigned short	sa_family_t;
116 
117 #define	__SOCKADDR_COMMON(sa_prefix) \
118   sa_family_t sa_prefix##family
119 
120 /* Ditto, for IPv6.  */
121 struct sockaddr_in6
122   {
123     __SOCKADDR_COMMON (sin6_);
124     u_int16_t sin6_port;		/* Transport layer port # */
125     u_int32_t sin6_flowinfo;	/* IPv6 flow information */
126     struct in6_addr sin6_addr;	/* IPv6 address */
127   };
128 
129 #ifndef EAI_ADDRFAMILY
130 struct addrinfo {
131 	int	ai_flags;	/* AI_PASSIVE, AI_CANONNAME */
132 	int	ai_family;	/* PF_xxx */
133 	int	ai_socktype;	/* SOCK_xxx */
134 	int	ai_protocol;	/* 0 or IPPROTO_xxx for IPv4 and IPv6 */
135 	size_t	ai_addrlen;	/* length of ai_addr */
136 	char	*ai_canonname;	/* canonical name for hostname */
137 	struct sockaddr *ai_addr;	/* binary address */
138 	struct addrinfo *ai_next;	/* next structure in linked list */
139 };
140 #endif /* EAI_ADDRFAMILY */
141 #endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
142 #else /* _WIN32 */
143 #include <netdb.h>	/* for "struct addrinfo" */
144 #endif /* _WIN32 */
145 #endif /* INET6 */
146 #include <pcap/namedb.h>
147 
148 #include "nametoaddr.h"
149 
150 #define ETHERMTU	1500
151 
152 #ifndef ETHERTYPE_TEB
153 #define ETHERTYPE_TEB 0x6558
154 #endif
155 
156 #ifndef IPPROTO_HOPOPTS
157 #define IPPROTO_HOPOPTS 0
158 #endif
159 #ifndef IPPROTO_ROUTING
160 #define IPPROTO_ROUTING 43
161 #endif
162 #ifndef IPPROTO_FRAGMENT
163 #define IPPROTO_FRAGMENT 44
164 #endif
165 #ifndef IPPROTO_DSTOPTS
166 #define IPPROTO_DSTOPTS 60
167 #endif
168 #ifndef IPPROTO_SCTP
169 #define IPPROTO_SCTP 132
170 #endif
171 
172 #define GENEVE_PORT 6081
173 
174 #ifdef HAVE_OS_PROTO_H
175 #include "os-proto.h"
176 #endif
177 
178 #define JMP(c) ((c)|BPF_JMP|BPF_K)
179 
180 /*
181  * "Push" the current value of the link-layer header type and link-layer
182  * header offset onto a "stack", and set a new value.  (It's not a
183  * full-blown stack; we keep only the top two items.)
184  */
185 #define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
186 { \
187 	(cs)->prevlinktype = (cs)->linktype; \
188 	(cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
189 	(cs)->linktype = (new_linktype); \
190 	(cs)->off_linkhdr.is_variable = (new_is_variable); \
191 	(cs)->off_linkhdr.constant_part = (new_constant_part); \
192 	(cs)->off_linkhdr.reg = (new_reg); \
193 	(cs)->is_geneve = 0; \
194 }
195 
196 /*
197  * Offset "not set" value.
198  */
199 #define OFFSET_NOT_SET	0xffffffffU
200 
201 /*
202  * Absolute offsets, which are offsets from the beginning of the raw
203  * packet data, are, in the general case, the sum of a variable value
204  * and a constant value; the variable value may be absent, in which
205  * case the offset is only the constant value, and the constant value
206  * may be zero, in which case the offset is only the variable value.
207  *
208  * bpf_abs_offset is a structure containing all that information:
209  *
210  *   is_variable is 1 if there's a variable part.
211  *
212  *   constant_part is the constant part of the value, possibly zero;
213  *
214  *   if is_variable is 1, reg is the register number for a register
215  *   containing the variable value if the register has been assigned,
216  *   and -1 otherwise.
217  */
218 typedef struct {
219 	int	is_variable;
220 	u_int	constant_part;
221 	int	reg;
222 } bpf_abs_offset;
223 
224 /*
225  * Value passed to gen_load_a() to indicate what the offset argument
226  * is relative to the beginning of.
227  */
228 enum e_offrel {
229 	OR_PACKET,		/* full packet data */
230 	OR_LINKHDR,		/* link-layer header */
231 	OR_PREVLINKHDR,		/* previous link-layer header */
232 	OR_LLC,			/* 802.2 LLC header */
233 	OR_PREVMPLSHDR,		/* previous MPLS header */
234 	OR_LINKTYPE,		/* link-layer type */
235 	OR_LINKPL,		/* link-layer payload */
236 	OR_LINKPL_NOSNAP,	/* link-layer payload, with no SNAP header at the link layer */
237 	OR_TRAN_IPV4,		/* transport-layer header, with IPv4 network layer */
238 	OR_TRAN_IPV6		/* transport-layer header, with IPv6 network layer */
239 };
240 
241 /*
242  * We divy out chunks of memory rather than call malloc each time so
243  * we don't have to worry about leaking memory.  It's probably
244  * not a big deal if all this memory was wasted but if this ever
245  * goes into a library that would probably not be a good idea.
246  *
247  * XXX - this *is* in a library....
248  */
249 #define NCHUNKS 16
250 #define CHUNK0SIZE 1024
251 struct chunk {
252 	size_t n_left;
253 	void *m;
254 };
255 
256 /* Code generator state */
257 
258 struct _compiler_state {
259 	jmp_buf top_ctx;
260 	pcap_t *bpf_pcap;
261 
262 	struct icode ic;
263 
264 	int snaplen;
265 
266 	int linktype;
267 	int prevlinktype;
268 	int outermostlinktype;
269 
270 	bpf_u_int32 netmask;
271 	int no_optimize;
272 
273 	/* Hack for handling VLAN and MPLS stacks. */
274 	u_int label_stack_depth;
275 	u_int vlan_stack_depth;
276 
277 	/* XXX */
278 	u_int pcap_fddipad;
279 
280 #ifdef INET6
281 	/*
282 	 * As errors are handled by a longjmp, anything allocated must
283 	 * be freed in the longjmp handler, so it must be reachable
284 	 * from that handler.
285 	 *
286 	 * One thing that's allocated is the result of pcap_nametoaddrinfo();
287 	 * it must be freed with freeaddrinfo().  This variable points to
288 	 * any addrinfo structure that would need to be freed.
289 	 */
290 	struct addrinfo *ai;
291 #endif
292 
293 	/*
294 	 * Various code constructs need to know the layout of the packet.
295 	 * These values give the necessary offsets from the beginning
296 	 * of the packet data.
297 	 */
298 
299 	/*
300 	 * Absolute offset of the beginning of the link-layer header.
301 	 */
302 	bpf_abs_offset off_linkhdr;
303 
304 	/*
305 	 * If we're checking a link-layer header for a packet encapsulated
306 	 * in another protocol layer, this is the equivalent information
307 	 * for the previous layers' link-layer header from the beginning
308 	 * of the raw packet data.
309 	 */
310 	bpf_abs_offset off_prevlinkhdr;
311 
312 	/*
313 	 * This is the equivalent information for the outermost layers'
314 	 * link-layer header.
315 	 */
316 	bpf_abs_offset off_outermostlinkhdr;
317 
318 	/*
319 	 * Absolute offset of the beginning of the link-layer payload.
320 	 */
321 	bpf_abs_offset off_linkpl;
322 
323 	/*
324 	 * "off_linktype" is the offset to information in the link-layer
325 	 * header giving the packet type. This is an absolute offset
326 	 * from the beginning of the packet.
327 	 *
328 	 * For Ethernet, it's the offset of the Ethernet type field; this
329 	 * means that it must have a value that skips VLAN tags.
330 	 *
331 	 * For link-layer types that always use 802.2 headers, it's the
332 	 * offset of the LLC header; this means that it must have a value
333 	 * that skips VLAN tags.
334 	 *
335 	 * For PPP, it's the offset of the PPP type field.
336 	 *
337 	 * For Cisco HDLC, it's the offset of the CHDLC type field.
338 	 *
339 	 * For BSD loopback, it's the offset of the AF_ value.
340 	 *
341 	 * For Linux cooked sockets, it's the offset of the type field.
342 	 *
343 	 * off_linktype.constant_part is set to OFFSET_NOT_SET for no
344 	 * encapsulation, in which case, IP is assumed.
345 	 */
346 	bpf_abs_offset off_linktype;
347 
348 	/*
349 	 * TRUE if the link layer includes an ATM pseudo-header.
350 	 */
351 	int is_atm;
352 
353 	/*
354 	 * TRUE if "geneve" appeared in the filter; it causes us to
355 	 * generate code that checks for a Geneve header and assume
356 	 * that later filters apply to the encapsulated payload.
357 	 */
358 	int is_geneve;
359 
360 	/*
361 	 * These are offsets for the ATM pseudo-header.
362 	 */
363 	u_int off_vpi;
364 	u_int off_vci;
365 	u_int off_proto;
366 
367 	/*
368 	 * These are offsets for the MTP2 fields.
369 	 */
370 	u_int off_li;
371 	u_int off_li_hsl;
372 
373 	/*
374 	 * These are offsets for the MTP3 fields.
375 	 */
376 	u_int off_sio;
377 	u_int off_opc;
378 	u_int off_dpc;
379 	u_int off_sls;
380 
381 	/*
382 	 * This is the offset of the first byte after the ATM pseudo_header,
383 	 * or -1 if there is no ATM pseudo-header.
384 	 */
385 	u_int off_payload;
386 
387 	/*
388 	 * These are offsets to the beginning of the network-layer header.
389 	 * They are relative to the beginning of the link-layer payload
390 	 * (i.e., they don't include off_linkhdr.constant_part or
391 	 * off_linkpl.constant_part).
392 	 *
393 	 * If the link layer never uses 802.2 LLC:
394 	 *
395 	 *	"off_nl" and "off_nl_nosnap" are the same.
396 	 *
397 	 * If the link layer always uses 802.2 LLC:
398 	 *
399 	 *	"off_nl" is the offset if there's a SNAP header following
400 	 *	the 802.2 header;
401 	 *
402 	 *	"off_nl_nosnap" is the offset if there's no SNAP header.
403 	 *
404 	 * If the link layer is Ethernet:
405 	 *
406 	 *	"off_nl" is the offset if the packet is an Ethernet II packet
407 	 *	(we assume no 802.3+802.2+SNAP);
408 	 *
409 	 *	"off_nl_nosnap" is the offset if the packet is an 802.3 packet
410 	 *	with an 802.2 header following it.
411 	 */
412 	u_int off_nl;
413 	u_int off_nl_nosnap;
414 
415 	/*
416 	 * Here we handle simple allocation of the scratch registers.
417 	 * If too many registers are alloc'd, the allocator punts.
418 	 */
419 	int regused[BPF_MEMWORDS];
420 	int curreg;
421 
422 	/*
423 	 * Memory chunks.
424 	 */
425 	struct chunk chunks[NCHUNKS];
426 	int cur_chunk;
427 };
428 
429 void
bpf_syntax_error(compiler_state_t * cstate,const char * msg)430 bpf_syntax_error(compiler_state_t *cstate, const char *msg)
431 {
432 	bpf_error(cstate, "syntax error in filter expression: %s", msg);
433 	/* NOTREACHED */
434 }
435 
436 /* VARARGS */
437 void
bpf_error(compiler_state_t * cstate,const char * fmt,...)438 bpf_error(compiler_state_t *cstate, const char *fmt, ...)
439 {
440 	va_list ap;
441 
442 	va_start(ap, fmt);
443 	if (cstate->bpf_pcap != NULL)
444 		(void)pcap_vsnprintf(pcap_geterr(cstate->bpf_pcap),
445 		    PCAP_ERRBUF_SIZE, fmt, ap);
446 	va_end(ap);
447 	longjmp(cstate->top_ctx, 1);
448 	/* NOTREACHED */
449 }
450 
451 static void init_linktype(compiler_state_t *, pcap_t *);
452 
453 static void init_regs(compiler_state_t *);
454 static int alloc_reg(compiler_state_t *);
455 static void free_reg(compiler_state_t *, int);
456 
457 static void initchunks(compiler_state_t *cstate);
458 static void *newchunk(compiler_state_t *cstate, size_t);
459 static void freechunks(compiler_state_t *cstate);
460 static inline struct block *new_block(compiler_state_t *cstate, int);
461 static inline struct slist *new_stmt(compiler_state_t *cstate, int);
462 static struct block *gen_retblk(compiler_state_t *cstate, int);
463 static inline void syntax(compiler_state_t *cstate);
464 
465 static void backpatch(struct block *, struct block *);
466 static void merge(struct block *, struct block *);
467 static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
468     u_int, bpf_int32);
469 static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
470     u_int, bpf_int32);
471 static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
472     u_int, bpf_int32);
473 static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
474     u_int, bpf_int32);
475 static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
476     u_int, bpf_int32);
477 static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
478     u_int, bpf_int32, bpf_u_int32);
479 static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
480     u_int, const u_char *);
481 static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, bpf_u_int32,
482     bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32);
483 static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
484     u_int, u_int);
485 static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
486     u_int);
487 static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
488 static struct block *gen_uncond(compiler_state_t *, int);
489 static inline struct block *gen_true(compiler_state_t *);
490 static inline struct block *gen_false(compiler_state_t *);
491 static struct block *gen_ether_linktype(compiler_state_t *, int);
492 static struct block *gen_ipnet_linktype(compiler_state_t *, int);
493 static struct block *gen_linux_sll_linktype(compiler_state_t *, int);
494 static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
495 static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
496 static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
497 static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
498 static void insert_compute_vloffsets(compiler_state_t *, struct block *);
499 static struct slist *gen_abs_offset_varpart(compiler_state_t *,
500     bpf_abs_offset *);
501 static int ethertype_to_ppptype(int);
502 static struct block *gen_linktype(compiler_state_t *, int);
503 static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
504 static struct block *gen_llc_linktype(compiler_state_t *, int);
505 static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
506     int, int, u_int, u_int);
507 #ifdef INET6
508 static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
509     struct in6_addr *, int, int, u_int, u_int);
510 #endif
511 static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
512 static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
513 static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
514 static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
515 static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
516 static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
517 static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
518 static struct block *gen_mpls_linktype(compiler_state_t *, int);
519 static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
520     int, int, int);
521 #ifdef INET6
522 static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
523     struct in6_addr *, int, int, int);
524 #endif
525 #ifndef INET6
526 static struct block *gen_gateway(const u_char *, bpf_u_int32 **, int, int);
527 #endif
528 static struct block *gen_ipfrag(compiler_state_t *);
529 static struct block *gen_portatom(compiler_state_t *, int, bpf_int32);
530 static struct block *gen_portrangeatom(compiler_state_t *, int, bpf_int32,
531     bpf_int32);
532 static struct block *gen_portatom6(compiler_state_t *, int, bpf_int32);
533 static struct block *gen_portrangeatom6(compiler_state_t *, int, bpf_int32,
534     bpf_int32);
535 struct block *gen_portop(compiler_state_t *, int, int, int);
536 static struct block *gen_port(compiler_state_t *, int, int, int);
537 struct block *gen_portrangeop(compiler_state_t *, int, int, int, int);
538 static struct block *gen_portrange(compiler_state_t *, int, int, int, int);
539 struct block *gen_portop6(compiler_state_t *, int, int, int);
540 static struct block *gen_port6(compiler_state_t *, int, int, int);
541 struct block *gen_portrangeop6(compiler_state_t *, int, int, int, int);
542 static struct block *gen_portrange6(compiler_state_t *, int, int, int, int);
543 static int lookup_proto(compiler_state_t *, const char *, int);
544 static struct block *gen_protochain(compiler_state_t *, int, int, int);
545 static struct block *gen_proto(compiler_state_t *, int, int, int);
546 static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
547 static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
548 static struct block *gen_mac_multicast(compiler_state_t *, int);
549 static struct block *gen_len(compiler_state_t *, int, int);
550 static struct block *gen_check_802_11_data_frame(compiler_state_t *);
551 static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
552 
553 static struct block *gen_ppi_dlt_check(compiler_state_t *);
554 static struct block *gen_msg_abbrev(compiler_state_t *, int type);
555 
556 static void
initchunks(compiler_state_t * cstate)557 initchunks(compiler_state_t *cstate)
558 {
559 	int i;
560 
561 	for (i = 0; i < NCHUNKS; i++) {
562 		cstate->chunks[i].n_left = 0;
563 		cstate->chunks[i].m = NULL;
564 	}
565 	cstate->cur_chunk = 0;
566 }
567 
568 static void *
newchunk(compiler_state_t * cstate,size_t n)569 newchunk(compiler_state_t *cstate, size_t n)
570 {
571 	struct chunk *cp;
572 	int k;
573 	size_t size;
574 
575 #ifndef __NetBSD__
576 	/* XXX Round up to nearest long. */
577 	n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
578 #else
579 	/* XXX Round up to structure boundary. */
580 	n = ALIGN(n);
581 #endif
582 
583 	cp = &cstate->chunks[cstate->cur_chunk];
584 	if (n > cp->n_left) {
585 		++cp, k = ++cstate->cur_chunk;
586 		if (k >= NCHUNKS)
587 			bpf_error(cstate, "out of memory");
588 		size = CHUNK0SIZE << k;
589 		cp->m = (void *)malloc(size);
590 		if (cp->m == NULL)
591 			bpf_error(cstate, "out of memory");
592 		memset((char *)cp->m, 0, size);
593 		cp->n_left = size;
594 		if (n > size)
595 			bpf_error(cstate, "out of memory");
596 	}
597 	cp->n_left -= n;
598 	return (void *)((char *)cp->m + cp->n_left);
599 }
600 
601 static void
freechunks(compiler_state_t * cstate)602 freechunks(compiler_state_t *cstate)
603 {
604 	int i;
605 
606 	for (i = 0; i < NCHUNKS; ++i)
607 		if (cstate->chunks[i].m != NULL)
608 			free(cstate->chunks[i].m);
609 }
610 
611 /*
612  * A strdup whose allocations are freed after code generation is over.
613  */
614 char *
sdup(compiler_state_t * cstate,const char * s)615 sdup(compiler_state_t *cstate, const char *s)
616 {
617 	size_t n = strlen(s) + 1;
618 	char *cp = newchunk(cstate, n);
619 
620 	strlcpy(cp, s, n);
621 	return (cp);
622 }
623 
624 static inline struct block *
new_block(compiler_state_t * cstate,int code)625 new_block(compiler_state_t *cstate, int code)
626 {
627 	struct block *p;
628 
629 	p = (struct block *)newchunk(cstate, sizeof(*p));
630 	p->s.code = code;
631 	p->head = p;
632 
633 	return p;
634 }
635 
636 static inline struct slist *
new_stmt(compiler_state_t * cstate,int code)637 new_stmt(compiler_state_t *cstate, int code)
638 {
639 	struct slist *p;
640 
641 	p = (struct slist *)newchunk(cstate, sizeof(*p));
642 	p->s.code = code;
643 
644 	return p;
645 }
646 
647 static struct block *
gen_retblk(compiler_state_t * cstate,int v)648 gen_retblk(compiler_state_t *cstate, int v)
649 {
650 	struct block *b = new_block(cstate, BPF_RET|BPF_K);
651 
652 	b->s.k = v;
653 	return b;
654 }
655 
656 static inline void
syntax(compiler_state_t * cstate)657 syntax(compiler_state_t *cstate)
658 {
659 	bpf_error(cstate, "syntax error in filter expression");
660 }
661 
662 int
pcap_compile(pcap_t * p,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)663 pcap_compile(pcap_t *p, struct bpf_program *program,
664 	     const char *buf, int optimize, bpf_u_int32 mask)
665 {
666 	compiler_state_t cstate;
667 	const char * volatile xbuf = buf;
668 	yyscan_t scanner = NULL;
669 	YY_BUFFER_STATE in_buffer = NULL;
670 	u_int len;
671 	int  rc;
672 
673 #ifdef _WIN32
674 	static int done = 0;
675 
676 	if (!done)
677 		pcap_wsockinit();
678 	done = 1;
679 #endif
680 
681 	/*
682 	 * If this pcap_t hasn't been activated, it doesn't have a
683 	 * link-layer type, so we can't use it.
684 	 */
685 	if (!p->activated) {
686 		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
687 		    "not-yet-activated pcap_t passed to pcap_compile");
688 		rc = -1;
689 		goto quit;
690 	}
691 	initchunks(&cstate);
692 	cstate.no_optimize = 0;
693 	cstate.ai = NULL;
694 	cstate.ic.root = NULL;
695 	cstate.ic.cur_mark = 0;
696 	cstate.bpf_pcap = p;
697 	init_regs(&cstate);
698 
699 	if (setjmp(cstate.top_ctx)) {
700 #ifdef INET6
701 		if (cstate.ai != NULL)
702 			freeaddrinfo(cstate.ai);
703 #endif
704 		rc = -1;
705 		goto quit;
706 	}
707 
708 	cstate.netmask = mask;
709 
710 	cstate.snaplen = pcap_snapshot(p);
711 	if (cstate.snaplen == 0) {
712 		pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
713 			 "snaplen of 0 rejects all packets");
714 		rc = -1;
715 		goto quit;
716 	}
717 
718 	if (pcap_lex_init(&scanner) != 0)
719 		bpf_error(&cstate, "can't initialize scanner: %s", pcap_strerror(errno));
720 	in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
721 
722 	/*
723 	 * Associate the compiler state with the lexical analyzer
724 	 * state.
725 	 */
726 	pcap_set_extra(&cstate, scanner);
727 
728 	init_linktype(&cstate, p);
729 	(void)pcap_parse(scanner, &cstate);
730 
731 	if (cstate.ic.root == NULL)
732 		cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
733 
734 	if (optimize && !cstate.no_optimize) {
735 		bpf_optimize(&cstate, &cstate.ic);
736 		if (cstate.ic.root == NULL ||
737 		    (cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0))
738 			bpf_error(&cstate, "expression rejects all packets");
739 	}
740 	program->bf_insns = icode_to_fcode(&cstate, &cstate.ic, cstate.ic.root, &len);
741 	program->bf_len = len;
742 
743 	rc = 0;  /* We're all okay */
744 
745 quit:
746 	/*
747 	 * Clean up everything for the lexical analyzer.
748 	 */
749 	if (in_buffer != NULL)
750 		pcap__delete_buffer(in_buffer, scanner);
751 	if (scanner != NULL)
752 		pcap_lex_destroy(scanner);
753 
754 	/*
755 	 * Clean up our own allocated memory.
756 	 */
757 	freechunks(&cstate);
758 
759 	return (rc);
760 }
761 
762 /*
763  * entry point for using the compiler with no pcap open
764  * pass in all the stuff that is needed explicitly instead.
765  */
766 int
pcap_compile_nopcap(int snaplen_arg,int linktype_arg,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)767 pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
768 		    struct bpf_program *program,
769 	     const char *buf, int optimize, bpf_u_int32 mask)
770 {
771 	pcap_t *p;
772 	int ret;
773 
774 	p = pcap_open_dead(linktype_arg, snaplen_arg);
775 	if (p == NULL)
776 		return (-1);
777 	ret = pcap_compile(p, program, buf, optimize, mask);
778 	pcap_close(p);
779 	return (ret);
780 }
781 
782 /*
783  * Clean up a "struct bpf_program" by freeing all the memory allocated
784  * in it.
785  */
786 void
pcap_freecode(struct bpf_program * program)787 pcap_freecode(struct bpf_program *program)
788 {
789 	program->bf_len = 0;
790 	if (program->bf_insns != NULL) {
791 		free((char *)program->bf_insns);
792 		program->bf_insns = NULL;
793 	}
794 }
795 
796 /*
797  * Backpatch the blocks in 'list' to 'target'.  The 'sense' field indicates
798  * which of the jt and jf fields has been resolved and which is a pointer
799  * back to another unresolved block (or nil).  At least one of the fields
800  * in each block is already resolved.
801  */
802 static void
backpatch(list,target)803 backpatch(list, target)
804 	struct block *list, *target;
805 {
806 	struct block *next;
807 
808 	while (list) {
809 		if (!list->sense) {
810 			next = JT(list);
811 			JT(list) = target;
812 		} else {
813 			next = JF(list);
814 			JF(list) = target;
815 		}
816 		list = next;
817 	}
818 }
819 
820 /*
821  * Merge the lists in b0 and b1, using the 'sense' field to indicate
822  * which of jt and jf is the link.
823  */
824 static void
merge(b0,b1)825 merge(b0, b1)
826 	struct block *b0, *b1;
827 {
828 	register struct block **p = &b0;
829 
830 	/* Find end of list. */
831 	while (*p)
832 		p = !((*p)->sense) ? &JT(*p) : &JF(*p);
833 
834 	/* Concatenate the lists. */
835 	*p = b1;
836 }
837 
838 void
finish_parse(compiler_state_t * cstate,struct block * p)839 finish_parse(compiler_state_t *cstate, struct block *p)
840 {
841 	struct block *ppi_dlt_check;
842 
843 	/*
844 	 * Insert before the statements of the first (root) block any
845 	 * statements needed to load the lengths of any variable-length
846 	 * headers into registers.
847 	 *
848 	 * XXX - a fancier strategy would be to insert those before the
849 	 * statements of all blocks that use those lengths and that
850 	 * have no predecessors that use them, so that we only compute
851 	 * the lengths if we need them.  There might be even better
852 	 * approaches than that.
853 	 *
854 	 * However, those strategies would be more complicated, and
855 	 * as we don't generate code to compute a length if the
856 	 * program has no tests that use the length, and as most
857 	 * tests will probably use those lengths, we would just
858 	 * postpone computing the lengths so that it's not done
859 	 * for tests that fail early, and it's not clear that's
860 	 * worth the effort.
861 	 */
862 	insert_compute_vloffsets(cstate, p->head);
863 
864 	/*
865 	 * For DLT_PPI captures, generate a check of the per-packet
866 	 * DLT value to make sure it's DLT_IEEE802_11.
867 	 *
868 	 * XXX - TurboCap cards use DLT_PPI for Ethernet.
869 	 * Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
870 	 * with appropriate Ethernet information and use that rather
871 	 * than using something such as DLT_PPI where you don't know
872 	 * the link-layer header type until runtime, which, in the
873 	 * general case, would force us to generate both Ethernet *and*
874 	 * 802.11 code (*and* anything else for which PPI is used)
875 	 * and choose between them early in the BPF program?
876 	 */
877 	ppi_dlt_check = gen_ppi_dlt_check(cstate);
878 	if (ppi_dlt_check != NULL)
879 		gen_and(ppi_dlt_check, p);
880 
881 	backpatch(p, gen_retblk(cstate, cstate->snaplen));
882 	p->sense = !p->sense;
883 	backpatch(p, gen_retblk(cstate, 0));
884 	cstate->ic.root = p->head;
885 }
886 
887 void
gen_and(b0,b1)888 gen_and(b0, b1)
889 	struct block *b0, *b1;
890 {
891 	backpatch(b0, b1->head);
892 	b0->sense = !b0->sense;
893 	b1->sense = !b1->sense;
894 	merge(b1, b0);
895 	b1->sense = !b1->sense;
896 	b1->head = b0->head;
897 }
898 
899 void
gen_or(b0,b1)900 gen_or(b0, b1)
901 	struct block *b0, *b1;
902 {
903 	b0->sense = !b0->sense;
904 	backpatch(b0, b1->head);
905 	b0->sense = !b0->sense;
906 	merge(b1, b0);
907 	b1->head = b0->head;
908 }
909 
910 void
gen_not(b)911 gen_not(b)
912 	struct block *b;
913 {
914 	b->sense = !b->sense;
915 }
916 
917 static struct block *
gen_cmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)918 gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
919     u_int size, bpf_int32 v)
920 {
921 	return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
922 }
923 
924 static struct block *
gen_cmp_gt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)925 gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
926     u_int size, bpf_int32 v)
927 {
928 	return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
929 }
930 
931 static struct block *
gen_cmp_ge(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)932 gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
933     u_int size, bpf_int32 v)
934 {
935 	return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
936 }
937 
938 static struct block *
gen_cmp_lt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)939 gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
940     u_int size, bpf_int32 v)
941 {
942 	return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
943 }
944 
945 static struct block *
gen_cmp_le(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)946 gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
947     u_int size, bpf_int32 v)
948 {
949 	return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
950 }
951 
952 static struct block *
gen_mcmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v,bpf_u_int32 mask)953 gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
954     u_int size, bpf_int32 v, bpf_u_int32 mask)
955 {
956 	return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
957 }
958 
959 static struct block *
gen_bcmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,const u_char * v)960 gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
961     u_int size, const u_char *v)
962 {
963 	register struct block *b, *tmp;
964 
965 	b = NULL;
966 	while (size >= 4) {
967 		register const u_char *p = &v[size - 4];
968 		bpf_int32 w = ((bpf_int32)p[0] << 24) |
969 		    ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
970 
971 		tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W, w);
972 		if (b != NULL)
973 			gen_and(b, tmp);
974 		b = tmp;
975 		size -= 4;
976 	}
977 	while (size >= 2) {
978 		register const u_char *p = &v[size - 2];
979 		bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
980 
981 		tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H, w);
982 		if (b != NULL)
983 			gen_and(b, tmp);
984 		b = tmp;
985 		size -= 2;
986 	}
987 	if (size > 0) {
988 		tmp = gen_cmp(cstate, offrel, offset, BPF_B, (bpf_int32)v[0]);
989 		if (b != NULL)
990 			gen_and(b, tmp);
991 		b = tmp;
992 	}
993 	return b;
994 }
995 
996 /*
997  * AND the field of size "size" at offset "offset" relative to the header
998  * specified by "offrel" with "mask", and compare it with the value "v"
999  * with the test specified by "jtype"; if "reverse" is true, the test
1000  * should test the opposite of "jtype".
1001  */
1002 static struct block *
gen_ncmp(compiler_state_t * cstate,enum e_offrel offrel,bpf_u_int32 offset,bpf_u_int32 size,bpf_u_int32 mask,bpf_u_int32 jtype,int reverse,bpf_int32 v)1003 gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, bpf_u_int32 offset,
1004     bpf_u_int32 size, bpf_u_int32 mask, bpf_u_int32 jtype, int reverse,
1005     bpf_int32 v)
1006 {
1007 	struct slist *s, *s2;
1008 	struct block *b;
1009 
1010 	s = gen_load_a(cstate, offrel, offset, size);
1011 
1012 	if (mask != 0xffffffff) {
1013 		s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1014 		s2->s.k = mask;
1015 		sappend(s, s2);
1016 	}
1017 
1018 	b = new_block(cstate, JMP(jtype));
1019 	b->stmts = s;
1020 	b->s.k = v;
1021 	if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
1022 		gen_not(b);
1023 	return b;
1024 }
1025 
1026 static void
init_linktype(compiler_state_t * cstate,pcap_t * p)1027 init_linktype(compiler_state_t *cstate, pcap_t *p)
1028 {
1029 	cstate->pcap_fddipad = p->fddipad;
1030 
1031 	/*
1032 	 * We start out with only one link-layer header.
1033 	 */
1034 	cstate->outermostlinktype = pcap_datalink(p);
1035 	cstate->off_outermostlinkhdr.constant_part = 0;
1036 	cstate->off_outermostlinkhdr.is_variable = 0;
1037 	cstate->off_outermostlinkhdr.reg = -1;
1038 
1039 	cstate->prevlinktype = cstate->outermostlinktype;
1040 	cstate->off_prevlinkhdr.constant_part = 0;
1041 	cstate->off_prevlinkhdr.is_variable = 0;
1042 	cstate->off_prevlinkhdr.reg = -1;
1043 
1044 	cstate->linktype = cstate->outermostlinktype;
1045 	cstate->off_linkhdr.constant_part = 0;
1046 	cstate->off_linkhdr.is_variable = 0;
1047 	cstate->off_linkhdr.reg = -1;
1048 
1049 	/*
1050 	 * XXX
1051 	 */
1052 	cstate->off_linkpl.constant_part = 0;
1053 	cstate->off_linkpl.is_variable = 0;
1054 	cstate->off_linkpl.reg = -1;
1055 
1056 	cstate->off_linktype.constant_part = 0;
1057 	cstate->off_linktype.is_variable = 0;
1058 	cstate->off_linktype.reg = -1;
1059 
1060 	/*
1061 	 * Assume it's not raw ATM with a pseudo-header, for now.
1062 	 */
1063 	cstate->is_atm = 0;
1064 	cstate->off_vpi = -1;
1065 	cstate->off_vci = -1;
1066 	cstate->off_proto = -1;
1067 	cstate->off_payload = -1;
1068 
1069 	/*
1070 	 * And not Geneve.
1071 	 */
1072 	cstate->is_geneve = 0;
1073 
1074 	/*
1075 	 * And assume we're not doing SS7.
1076 	 */
1077 	cstate->off_li = -1;
1078 	cstate->off_li_hsl = -1;
1079 	cstate->off_sio = -1;
1080 	cstate->off_opc = -1;
1081 	cstate->off_dpc = -1;
1082 	cstate->off_sls = -1;
1083 
1084 	cstate->label_stack_depth = 0;
1085 	cstate->vlan_stack_depth = 0;
1086 
1087 	switch (cstate->linktype) {
1088 
1089 	case DLT_ARCNET:
1090 		cstate->off_linktype.constant_part = 2;
1091 		cstate->off_linkpl.constant_part = 6;
1092 		cstate->off_nl = 0;	/* XXX in reality, variable! */
1093 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1094 		break;
1095 
1096 	case DLT_ARCNET_LINUX:
1097 		cstate->off_linktype.constant_part = 4;
1098 		cstate->off_linkpl.constant_part = 8;
1099 		cstate->off_nl = 0;		/* XXX in reality, variable! */
1100 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1101 		break;
1102 
1103 	case DLT_EN10MB:
1104 		cstate->off_linktype.constant_part = 12;
1105 		cstate->off_linkpl.constant_part = 14;	/* Ethernet header length */
1106 		cstate->off_nl = 0;		/* Ethernet II */
1107 		cstate->off_nl_nosnap = 3;	/* 802.3+802.2 */
1108 		break;
1109 
1110 	case DLT_SLIP:
1111 		/*
1112 		 * SLIP doesn't have a link level type.  The 16 byte
1113 		 * header is hacked into our SLIP driver.
1114 		 */
1115 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1116 		cstate->off_linkpl.constant_part = 16;
1117 		cstate->off_nl = 0;
1118 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1119 		break;
1120 
1121 	case DLT_SLIP_BSDOS:
1122 		/* XXX this may be the same as the DLT_PPP_BSDOS case */
1123 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1124 		/* XXX end */
1125 		cstate->off_linkpl.constant_part = 24;
1126 		cstate->off_nl = 0;
1127 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1128 		break;
1129 
1130 	case DLT_NULL:
1131 	case DLT_LOOP:
1132 		cstate->off_linktype.constant_part = 0;
1133 		cstate->off_linkpl.constant_part = 4;
1134 		cstate->off_nl = 0;
1135 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1136 		break;
1137 
1138 	case DLT_ENC:
1139 		cstate->off_linktype.constant_part = 0;
1140 		cstate->off_linkpl.constant_part = 12;
1141 		cstate->off_nl = 0;
1142 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1143 		break;
1144 
1145 	case DLT_PPP:
1146 	case DLT_PPP_PPPD:
1147 	case DLT_C_HDLC:		/* BSD/OS Cisco HDLC */
1148 	case DLT_PPP_SERIAL:		/* NetBSD sync/async serial PPP */
1149 		cstate->off_linktype.constant_part = 2;	/* skip HDLC-like framing */
1150 		cstate->off_linkpl.constant_part = 4;	/* skip HDLC-like framing and protocol field */
1151 		cstate->off_nl = 0;
1152 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1153 		break;
1154 
1155 	case DLT_PPP_ETHER:
1156 		/*
1157 		 * This does no include the Ethernet header, and
1158 		 * only covers session state.
1159 		 */
1160 		cstate->off_linktype.constant_part = 6;
1161 		cstate->off_linkpl.constant_part = 8;
1162 		cstate->off_nl = 0;
1163 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1164 		break;
1165 
1166 	case DLT_PPP_BSDOS:
1167 		cstate->off_linktype.constant_part = 5;
1168 		cstate->off_linkpl.constant_part = 24;
1169 		cstate->off_nl = 0;
1170 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1171 		break;
1172 
1173 	case DLT_FDDI:
1174 		/*
1175 		 * FDDI doesn't really have a link-level type field.
1176 		 * We set "off_linktype" to the offset of the LLC header.
1177 		 *
1178 		 * To check for Ethernet types, we assume that SSAP = SNAP
1179 		 * is being used and pick out the encapsulated Ethernet type.
1180 		 * XXX - should we generate code to check for SNAP?
1181 		 */
1182 		cstate->off_linktype.constant_part = 13;
1183 		cstate->off_linktype.constant_part += cstate->pcap_fddipad;
1184 		cstate->off_linkpl.constant_part = 13;	/* FDDI MAC header length */
1185 		cstate->off_linkpl.constant_part += cstate->pcap_fddipad;
1186 		cstate->off_nl = 8;		/* 802.2+SNAP */
1187 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1188 		break;
1189 
1190 	case DLT_IEEE802:
1191 		/*
1192 		 * Token Ring doesn't really have a link-level type field.
1193 		 * We set "off_linktype" to the offset of the LLC header.
1194 		 *
1195 		 * To check for Ethernet types, we assume that SSAP = SNAP
1196 		 * is being used and pick out the encapsulated Ethernet type.
1197 		 * XXX - should we generate code to check for SNAP?
1198 		 *
1199 		 * XXX - the header is actually variable-length.
1200 		 * Some various Linux patched versions gave 38
1201 		 * as "off_linktype" and 40 as "off_nl"; however,
1202 		 * if a token ring packet has *no* routing
1203 		 * information, i.e. is not source-routed, the correct
1204 		 * values are 20 and 22, as they are in the vanilla code.
1205 		 *
1206 		 * A packet is source-routed iff the uppermost bit
1207 		 * of the first byte of the source address, at an
1208 		 * offset of 8, has the uppermost bit set.  If the
1209 		 * packet is source-routed, the total number of bytes
1210 		 * of routing information is 2 plus bits 0x1F00 of
1211 		 * the 16-bit value at an offset of 14 (shifted right
1212 		 * 8 - figure out which byte that is).
1213 		 */
1214 		cstate->off_linktype.constant_part = 14;
1215 		cstate->off_linkpl.constant_part = 14;	/* Token Ring MAC header length */
1216 		cstate->off_nl = 8;		/* 802.2+SNAP */
1217 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1218 		break;
1219 
1220 	case DLT_PRISM_HEADER:
1221 	case DLT_IEEE802_11_RADIO_AVS:
1222 	case DLT_IEEE802_11_RADIO:
1223 		cstate->off_linkhdr.is_variable = 1;
1224 		/* Fall through, 802.11 doesn't have a variable link
1225 		 * prefix but is otherwise the same. */
1226 
1227 	case DLT_IEEE802_11:
1228 		/*
1229 		 * 802.11 doesn't really have a link-level type field.
1230 		 * We set "off_linktype.constant_part" to the offset of
1231 		 * the LLC header.
1232 		 *
1233 		 * To check for Ethernet types, we assume that SSAP = SNAP
1234 		 * is being used and pick out the encapsulated Ethernet type.
1235 		 * XXX - should we generate code to check for SNAP?
1236 		 *
1237 		 * We also handle variable-length radio headers here.
1238 		 * The Prism header is in theory variable-length, but in
1239 		 * practice it's always 144 bytes long.  However, some
1240 		 * drivers on Linux use ARPHRD_IEEE80211_PRISM, but
1241 		 * sometimes or always supply an AVS header, so we
1242 		 * have to check whether the radio header is a Prism
1243 		 * header or an AVS header, so, in practice, it's
1244 		 * variable-length.
1245 		 */
1246 		cstate->off_linktype.constant_part = 24;
1247 		cstate->off_linkpl.constant_part = 0;	/* link-layer header is variable-length */
1248 		cstate->off_linkpl.is_variable = 1;
1249 		cstate->off_nl = 8;		/* 802.2+SNAP */
1250 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1251 		break;
1252 
1253 	case DLT_PPI:
1254 		/*
1255 		 * At the moment we treat PPI the same way that we treat
1256 		 * normal Radiotap encoded packets. The difference is in
1257 		 * the function that generates the code at the beginning
1258 		 * to compute the header length.  Since this code generator
1259 		 * of PPI supports bare 802.11 encapsulation only (i.e.
1260 		 * the encapsulated DLT should be DLT_IEEE802_11) we
1261 		 * generate code to check for this too.
1262 		 */
1263 		cstate->off_linktype.constant_part = 24;
1264 		cstate->off_linkpl.constant_part = 0;	/* link-layer header is variable-length */
1265 		cstate->off_linkpl.is_variable = 1;
1266 		cstate->off_linkhdr.is_variable = 1;
1267 		cstate->off_nl = 8;		/* 802.2+SNAP */
1268 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1269 		break;
1270 
1271 	case DLT_ATM_RFC1483:
1272 	case DLT_ATM_CLIP:	/* Linux ATM defines this */
1273 		/*
1274 		 * assume routed, non-ISO PDUs
1275 		 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1276 		 *
1277 		 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1278 		 * or PPP with the PPP NLPID (e.g., PPPoA)?  The
1279 		 * latter would presumably be treated the way PPPoE
1280 		 * should be, so you can do "pppoe and udp port 2049"
1281 		 * or "pppoa and tcp port 80" and have it check for
1282 		 * PPPo{A,E} and a PPP protocol of IP and....
1283 		 */
1284 		cstate->off_linktype.constant_part = 0;
1285 		cstate->off_linkpl.constant_part = 0;	/* packet begins with LLC header */
1286 		cstate->off_nl = 8;		/* 802.2+SNAP */
1287 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1288 		break;
1289 
1290 	case DLT_SUNATM:
1291 		/*
1292 		 * Full Frontal ATM; you get AALn PDUs with an ATM
1293 		 * pseudo-header.
1294 		 */
1295 		cstate->is_atm = 1;
1296 		cstate->off_vpi = SUNATM_VPI_POS;
1297 		cstate->off_vci = SUNATM_VCI_POS;
1298 		cstate->off_proto = PROTO_POS;
1299 		cstate->off_payload = SUNATM_PKT_BEGIN_POS;
1300 		cstate->off_linktype.constant_part = cstate->off_payload;
1301 		cstate->off_linkpl.constant_part = cstate->off_payload;	/* if LLC-encapsulated */
1302 		cstate->off_nl = 8;		/* 802.2+SNAP */
1303 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1304 		break;
1305 
1306 	case DLT_RAW:
1307 	case DLT_IPV4:
1308 	case DLT_IPV6:
1309 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1310 		cstate->off_linkpl.constant_part = 0;
1311 		cstate->off_nl = 0;
1312 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1313 		break;
1314 
1315 	case DLT_LINUX_SLL:	/* fake header for Linux cooked socket */
1316 		cstate->off_linktype.constant_part = 14;
1317 		cstate->off_linkpl.constant_part = 16;
1318 		cstate->off_nl = 0;
1319 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1320 		break;
1321 
1322 	case DLT_LTALK:
1323 		/*
1324 		 * LocalTalk does have a 1-byte type field in the LLAP header,
1325 		 * but really it just indicates whether there is a "short" or
1326 		 * "long" DDP packet following.
1327 		 */
1328 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1329 		cstate->off_linkpl.constant_part = 0;
1330 		cstate->off_nl = 0;
1331 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1332 		break;
1333 
1334 	case DLT_IP_OVER_FC:
1335 		/*
1336 		 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1337 		 * link-level type field.  We set "off_linktype" to the
1338 		 * offset of the LLC header.
1339 		 *
1340 		 * To check for Ethernet types, we assume that SSAP = SNAP
1341 		 * is being used and pick out the encapsulated Ethernet type.
1342 		 * XXX - should we generate code to check for SNAP? RFC
1343 		 * 2625 says SNAP should be used.
1344 		 */
1345 		cstate->off_linktype.constant_part = 16;
1346 		cstate->off_linkpl.constant_part = 16;
1347 		cstate->off_nl = 8;		/* 802.2+SNAP */
1348 		cstate->off_nl_nosnap = 3;	/* 802.2 */
1349 		break;
1350 
1351 	case DLT_FRELAY:
1352 		/*
1353 		 * XXX - we should set this to handle SNAP-encapsulated
1354 		 * frames (NLPID of 0x80).
1355 		 */
1356 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1357 		cstate->off_linkpl.constant_part = 0;
1358 		cstate->off_nl = 0;
1359 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1360 		break;
1361 
1362                 /*
1363                  * the only BPF-interesting FRF.16 frames are non-control frames;
1364                  * Frame Relay has a variable length link-layer
1365                  * so lets start with offset 4 for now and increments later on (FIXME);
1366                  */
1367 	case DLT_MFR:
1368 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1369 		cstate->off_linkpl.constant_part = 0;
1370 		cstate->off_nl = 4;
1371 		cstate->off_nl_nosnap = 0;	/* XXX - for now -> no 802.2 LLC */
1372 		break;
1373 
1374 	case DLT_APPLE_IP_OVER_IEEE1394:
1375 		cstate->off_linktype.constant_part = 16;
1376 		cstate->off_linkpl.constant_part = 18;
1377 		cstate->off_nl = 0;
1378 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1379 		break;
1380 
1381 	case DLT_SYMANTEC_FIREWALL:
1382 		cstate->off_linktype.constant_part = 6;
1383 		cstate->off_linkpl.constant_part = 44;
1384 		cstate->off_nl = 0;		/* Ethernet II */
1385 		cstate->off_nl_nosnap = 0;	/* XXX - what does it do with 802.3 packets? */
1386 		break;
1387 
1388 #ifdef HAVE_NET_PFVAR_H
1389 	case DLT_PFLOG:
1390 		cstate->off_linktype.constant_part = 0;
1391 		cstate->off_linkpl.constant_part = PFLOG_HDRLEN;
1392 		cstate->off_nl = 0;
1393 		cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
1394 		break;
1395 #endif
1396 
1397         case DLT_JUNIPER_MFR:
1398         case DLT_JUNIPER_MLFR:
1399         case DLT_JUNIPER_MLPPP:
1400         case DLT_JUNIPER_PPP:
1401         case DLT_JUNIPER_CHDLC:
1402         case DLT_JUNIPER_FRELAY:
1403 		cstate->off_linktype.constant_part = 4;
1404 		cstate->off_linkpl.constant_part = 4;
1405 		cstate->off_nl = 0;
1406 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1407                 break;
1408 
1409 	case DLT_JUNIPER_ATM1:
1410 		cstate->off_linktype.constant_part = 4;		/* in reality variable between 4-8 */
1411 		cstate->off_linkpl.constant_part = 4;	/* in reality variable between 4-8 */
1412 		cstate->off_nl = 0;
1413 		cstate->off_nl_nosnap = 10;
1414 		break;
1415 
1416 	case DLT_JUNIPER_ATM2:
1417 		cstate->off_linktype.constant_part = 8;		/* in reality variable between 8-12 */
1418 		cstate->off_linkpl.constant_part = 8;	/* in reality variable between 8-12 */
1419 		cstate->off_nl = 0;
1420 		cstate->off_nl_nosnap = 10;
1421 		break;
1422 
1423 		/* frames captured on a Juniper PPPoE service PIC
1424 		 * contain raw ethernet frames */
1425 	case DLT_JUNIPER_PPPOE:
1426         case DLT_JUNIPER_ETHER:
1427 		cstate->off_linkpl.constant_part = 14;
1428 		cstate->off_linktype.constant_part = 16;
1429 		cstate->off_nl = 18;		/* Ethernet II */
1430 		cstate->off_nl_nosnap = 21;	/* 802.3+802.2 */
1431 		break;
1432 
1433 	case DLT_JUNIPER_PPPOE_ATM:
1434 		cstate->off_linktype.constant_part = 4;
1435 		cstate->off_linkpl.constant_part = 6;
1436 		cstate->off_nl = 0;
1437 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1438 		break;
1439 
1440 	case DLT_JUNIPER_GGSN:
1441 		cstate->off_linktype.constant_part = 6;
1442 		cstate->off_linkpl.constant_part = 12;
1443 		cstate->off_nl = 0;
1444 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1445 		break;
1446 
1447 	case DLT_JUNIPER_ES:
1448 		cstate->off_linktype.constant_part = 6;
1449 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;	/* not really a network layer but raw IP addresses */
1450 		cstate->off_nl = -1;		/* not really a network layer but raw IP addresses */
1451 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1452 		break;
1453 
1454 	case DLT_JUNIPER_MONITOR:
1455 		cstate->off_linktype.constant_part = 12;
1456 		cstate->off_linkpl.constant_part = 12;
1457 		cstate->off_nl = 0;		/* raw IP/IP6 header */
1458 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1459 		break;
1460 
1461 	case DLT_BACNET_MS_TP:
1462 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1463 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1464 		cstate->off_nl = -1;
1465 		cstate->off_nl_nosnap = -1;
1466 		break;
1467 
1468 	case DLT_JUNIPER_SERVICES:
1469 		cstate->off_linktype.constant_part = 12;
1470 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;	/* L3 proto location dep. on cookie type */
1471 		cstate->off_nl = -1;		/* L3 proto location dep. on cookie type */
1472 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1473 		break;
1474 
1475 	case DLT_JUNIPER_VP:
1476 		cstate->off_linktype.constant_part = 18;
1477 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1478 		cstate->off_nl = -1;
1479 		cstate->off_nl_nosnap = -1;
1480 		break;
1481 
1482 	case DLT_JUNIPER_ST:
1483 		cstate->off_linktype.constant_part = 18;
1484 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1485 		cstate->off_nl = -1;
1486 		cstate->off_nl_nosnap = -1;
1487 		break;
1488 
1489 	case DLT_JUNIPER_ISM:
1490 		cstate->off_linktype.constant_part = 8;
1491 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1492 		cstate->off_nl = -1;
1493 		cstate->off_nl_nosnap = -1;
1494 		break;
1495 
1496 	case DLT_JUNIPER_VS:
1497 	case DLT_JUNIPER_SRX_E2E:
1498 	case DLT_JUNIPER_FIBRECHANNEL:
1499 	case DLT_JUNIPER_ATM_CEMIC:
1500 		cstate->off_linktype.constant_part = 8;
1501 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1502 		cstate->off_nl = -1;
1503 		cstate->off_nl_nosnap = -1;
1504 		break;
1505 
1506 	case DLT_MTP2:
1507 		cstate->off_li = 2;
1508 		cstate->off_li_hsl = 4;
1509 		cstate->off_sio = 3;
1510 		cstate->off_opc = 4;
1511 		cstate->off_dpc = 4;
1512 		cstate->off_sls = 7;
1513 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1514 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1515 		cstate->off_nl = -1;
1516 		cstate->off_nl_nosnap = -1;
1517 		break;
1518 
1519 	case DLT_MTP2_WITH_PHDR:
1520 		cstate->off_li = 6;
1521 		cstate->off_li_hsl = 8;
1522 		cstate->off_sio = 7;
1523 		cstate->off_opc = 8;
1524 		cstate->off_dpc = 8;
1525 		cstate->off_sls = 11;
1526 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1527 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1528 		cstate->off_nl = -1;
1529 		cstate->off_nl_nosnap = -1;
1530 		break;
1531 
1532 	case DLT_ERF:
1533 		cstate->off_li = 22;
1534 		cstate->off_li_hsl = 24;
1535 		cstate->off_sio = 23;
1536 		cstate->off_opc = 24;
1537 		cstate->off_dpc = 24;
1538 		cstate->off_sls = 27;
1539 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1540 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1541 		cstate->off_nl = -1;
1542 		cstate->off_nl_nosnap = -1;
1543 		break;
1544 
1545 	case DLT_PFSYNC:
1546 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1547 		cstate->off_linkpl.constant_part = 4;
1548 		cstate->off_nl = 0;
1549 		cstate->off_nl_nosnap = 0;
1550 		break;
1551 
1552 	case DLT_AX25_KISS:
1553 		/*
1554 		 * Currently, only raw "link[N:M]" filtering is supported.
1555 		 */
1556 		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
1557 		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1558 		cstate->off_nl = -1;		/* variable, min 16, max 71 steps of 7 */
1559 		cstate->off_nl_nosnap = -1;	/* no 802.2 LLC */
1560 		break;
1561 
1562 	case DLT_IPNET:
1563 		cstate->off_linktype.constant_part = 1;
1564 		cstate->off_linkpl.constant_part = 24;	/* ipnet header length */
1565 		cstate->off_nl = 0;
1566 		cstate->off_nl_nosnap = -1;
1567 		break;
1568 
1569 	case DLT_NETANALYZER:
1570 		cstate->off_linkhdr.constant_part = 4;	/* Ethernet header is past 4-byte pseudo-header */
1571 		cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1572 		cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14;	/* pseudo-header+Ethernet header length */
1573 		cstate->off_nl = 0;		/* Ethernet II */
1574 		cstate->off_nl_nosnap = 3;	/* 802.3+802.2 */
1575 		break;
1576 
1577 	case DLT_NETANALYZER_TRANSPARENT:
1578 		cstate->off_linkhdr.constant_part = 12;	/* MAC header is past 4-byte pseudo-header, preamble, and SFD */
1579 		cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1580 		cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14;	/* pseudo-header+preamble+SFD+Ethernet header length */
1581 		cstate->off_nl = 0;		/* Ethernet II */
1582 		cstate->off_nl_nosnap = 3;	/* 802.3+802.2 */
1583 		break;
1584 
1585 	default:
1586 		/*
1587 		 * For values in the range in which we've assigned new
1588 		 * DLT_ values, only raw "link[N:M]" filtering is supported.
1589 		 */
1590 		if (cstate->linktype >= DLT_MATCHING_MIN &&
1591 		    cstate->linktype <= DLT_MATCHING_MAX) {
1592 			cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1593 			cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1594 			cstate->off_nl = -1;
1595 			cstate->off_nl_nosnap = -1;
1596 		} else {
1597 			bpf_error(cstate, "unknown data link type %d", cstate->linktype);
1598 		}
1599 		break;
1600 	}
1601 
1602 	cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr;
1603 }
1604 
1605 /*
1606  * Load a value relative to the specified absolute offset.
1607  */
1608 static struct slist *
gen_load_absoffsetrel(compiler_state_t * cstate,bpf_abs_offset * abs_offset,u_int offset,u_int size)1609 gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset,
1610     u_int offset, u_int size)
1611 {
1612 	struct slist *s, *s2;
1613 
1614 	s = gen_abs_offset_varpart(cstate, abs_offset);
1615 
1616 	/*
1617 	 * If "s" is non-null, it has code to arrange that the X register
1618 	 * contains the variable part of the absolute offset, so we
1619 	 * generate a load relative to that, with an offset of
1620 	 * abs_offset->constant_part + offset.
1621 	 *
1622 	 * Otherwise, we can do an absolute load with an offset of
1623 	 * abs_offset->constant_part + offset.
1624 	 */
1625 	if (s != NULL) {
1626 		/*
1627 		 * "s" points to a list of statements that puts the
1628 		 * variable part of the absolute offset into the X register.
1629 		 * Do an indirect load, to use the X register as an offset.
1630 		 */
1631 		s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1632 		s2->s.k = abs_offset->constant_part + offset;
1633 		sappend(s, s2);
1634 	} else {
1635 		/*
1636 		 * There is no variable part of the absolute offset, so
1637 		 * just do an absolute load.
1638 		 */
1639 		s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1640 		s->s.k = abs_offset->constant_part + offset;
1641 	}
1642 	return s;
1643 }
1644 
1645 /*
1646  * Load a value relative to the beginning of the specified header.
1647  */
1648 static struct slist *
gen_load_a(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size)1649 gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1650     u_int size)
1651 {
1652 	struct slist *s, *s2;
1653 
1654 	switch (offrel) {
1655 
1656 	case OR_PACKET:
1657                 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1658                 s->s.k = offset;
1659 		break;
1660 
1661 	case OR_LINKHDR:
1662 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size);
1663 		break;
1664 
1665 	case OR_PREVLINKHDR:
1666 		s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size);
1667 		break;
1668 
1669 	case OR_LLC:
1670 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size);
1671 		break;
1672 
1673 	case OR_PREVMPLSHDR:
1674 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size);
1675 		break;
1676 
1677 	case OR_LINKPL:
1678 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size);
1679 		break;
1680 
1681 	case OR_LINKPL_NOSNAP:
1682 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size);
1683 		break;
1684 
1685 	case OR_LINKTYPE:
1686 		s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size);
1687 		break;
1688 
1689 	case OR_TRAN_IPV4:
1690 		/*
1691 		 * Load the X register with the length of the IPv4 header
1692 		 * (plus the offset of the link-layer header, if it's
1693 		 * preceded by a variable-length header such as a radio
1694 		 * header), in bytes.
1695 		 */
1696 		s = gen_loadx_iphdrlen(cstate);
1697 
1698 		/*
1699 		 * Load the item at {offset of the link-layer payload} +
1700 		 * {offset, relative to the start of the link-layer
1701 		 * paylod, of the IPv4 header} + {length of the IPv4 header} +
1702 		 * {specified offset}.
1703 		 *
1704 		 * If the offset of the link-layer payload is variable,
1705 		 * the variable part of that offset is included in the
1706 		 * value in the X register, and we include the constant
1707 		 * part in the offset of the load.
1708 		 */
1709 		s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1710 		s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset;
1711 		sappend(s, s2);
1712 		break;
1713 
1714 	case OR_TRAN_IPV6:
1715 		s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size);
1716 		break;
1717 
1718 	default:
1719 		abort();
1720 		return NULL;
1721 	}
1722 	return s;
1723 }
1724 
1725 /*
1726  * Generate code to load into the X register the sum of the length of
1727  * the IPv4 header and the variable part of the offset of the link-layer
1728  * payload.
1729  */
1730 static struct slist *
gen_loadx_iphdrlen(compiler_state_t * cstate)1731 gen_loadx_iphdrlen(compiler_state_t *cstate)
1732 {
1733 	struct slist *s, *s2;
1734 
1735 	s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
1736 	if (s != NULL) {
1737 		/*
1738 		 * The offset of the link-layer payload has a variable
1739 		 * part.  "s" points to a list of statements that put
1740 		 * the variable part of that offset into the X register.
1741 		 *
1742 		 * The 4*([k]&0xf) addressing mode can't be used, as we
1743 		 * don't have a constant offset, so we have to load the
1744 		 * value in question into the A register and add to it
1745 		 * the value from the X register.
1746 		 */
1747 		s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
1748 		s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1749 		sappend(s, s2);
1750 		s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1751 		s2->s.k = 0xf;
1752 		sappend(s, s2);
1753 		s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
1754 		s2->s.k = 2;
1755 		sappend(s, s2);
1756 
1757 		/*
1758 		 * The A register now contains the length of the IP header.
1759 		 * We need to add to it the variable part of the offset of
1760 		 * the link-layer payload, which is still in the X
1761 		 * register, and move the result into the X register.
1762 		 */
1763 		sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
1764 		sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
1765 	} else {
1766 		/*
1767 		 * The offset of the link-layer payload is a constant,
1768 		 * so no code was generated to load the (non-existent)
1769 		 * variable part of that offset.
1770 		 *
1771 		 * This means we can use the 4*([k]&0xf) addressing
1772 		 * mode.  Load the length of the IPv4 header, which
1773 		 * is at an offset of cstate->off_nl from the beginning of
1774 		 * the link-layer payload, and thus at an offset of
1775 		 * cstate->off_linkpl.constant_part + cstate->off_nl from the beginning
1776 		 * of the raw packet data, using that addressing mode.
1777 		 */
1778 		s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
1779 		s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1780 	}
1781 	return s;
1782 }
1783 
1784 static struct block *
gen_uncond(compiler_state_t * cstate,int rsense)1785 gen_uncond(compiler_state_t *cstate, int rsense)
1786 {
1787 	struct block *b;
1788 	struct slist *s;
1789 
1790 	s = new_stmt(cstate, BPF_LD|BPF_IMM);
1791 	s->s.k = !rsense;
1792 	b = new_block(cstate, JMP(BPF_JEQ));
1793 	b->stmts = s;
1794 
1795 	return b;
1796 }
1797 
1798 static inline struct block *
gen_true(compiler_state_t * cstate)1799 gen_true(compiler_state_t *cstate)
1800 {
1801 	return gen_uncond(cstate, 1);
1802 }
1803 
1804 static inline struct block *
gen_false(compiler_state_t * cstate)1805 gen_false(compiler_state_t *cstate)
1806 {
1807 	return gen_uncond(cstate, 0);
1808 }
1809 
1810 /*
1811  * Byte-swap a 32-bit number.
1812  * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1813  * big-endian platforms.)
1814  */
1815 #define	SWAPLONG(y) \
1816 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1817 
1818 /*
1819  * Generate code to match a particular packet type.
1820  *
1821  * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1822  * value, if <= ETHERMTU.  We use that to determine whether to
1823  * match the type/length field or to check the type/length field for
1824  * a value <= ETHERMTU to see whether it's a type field and then do
1825  * the appropriate test.
1826  */
1827 static struct block *
gen_ether_linktype(compiler_state_t * cstate,int proto)1828 gen_ether_linktype(compiler_state_t *cstate, int proto)
1829 {
1830 	struct block *b0, *b1;
1831 
1832 	switch (proto) {
1833 
1834 	case LLCSAP_ISONS:
1835 	case LLCSAP_IP:
1836 	case LLCSAP_NETBEUI:
1837 		/*
1838 		 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1839 		 * so we check the DSAP and SSAP.
1840 		 *
1841 		 * LLCSAP_IP checks for IP-over-802.2, rather
1842 		 * than IP-over-Ethernet or IP-over-SNAP.
1843 		 *
1844 		 * XXX - should we check both the DSAP and the
1845 		 * SSAP, like this, or should we check just the
1846 		 * DSAP, as we do for other types <= ETHERMTU
1847 		 * (i.e., other SAP values)?
1848 		 */
1849 		b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1850 		gen_not(b0);
1851 		b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
1852 			     ((proto << 8) | proto));
1853 		gen_and(b0, b1);
1854 		return b1;
1855 
1856 	case LLCSAP_IPX:
1857 		/*
1858 		 * Check for;
1859 		 *
1860 		 *	Ethernet_II frames, which are Ethernet
1861 		 *	frames with a frame type of ETHERTYPE_IPX;
1862 		 *
1863 		 *	Ethernet_802.3 frames, which are 802.3
1864 		 *	frames (i.e., the type/length field is
1865 		 *	a length field, <= ETHERMTU, rather than
1866 		 *	a type field) with the first two bytes
1867 		 *	after the Ethernet/802.3 header being
1868 		 *	0xFFFF;
1869 		 *
1870 		 *	Ethernet_802.2 frames, which are 802.3
1871 		 *	frames with an 802.2 LLC header and
1872 		 *	with the IPX LSAP as the DSAP in the LLC
1873 		 *	header;
1874 		 *
1875 		 *	Ethernet_SNAP frames, which are 802.3
1876 		 *	frames with an LLC header and a SNAP
1877 		 *	header and with an OUI of 0x000000
1878 		 *	(encapsulated Ethernet) and a protocol
1879 		 *	ID of ETHERTYPE_IPX in the SNAP header.
1880 		 *
1881 		 * XXX - should we generate the same code both
1882 		 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
1883 		 */
1884 
1885 		/*
1886 		 * This generates code to check both for the
1887 		 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
1888 		 */
1889 		b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
1890 		b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
1891 		gen_or(b0, b1);
1892 
1893 		/*
1894 		 * Now we add code to check for SNAP frames with
1895 		 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
1896 		 */
1897 		b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
1898 		gen_or(b0, b1);
1899 
1900 		/*
1901 		 * Now we generate code to check for 802.3
1902 		 * frames in general.
1903 		 */
1904 		b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1905 		gen_not(b0);
1906 
1907 		/*
1908 		 * Now add the check for 802.3 frames before the
1909 		 * check for Ethernet_802.2 and Ethernet_802.3,
1910 		 * as those checks should only be done on 802.3
1911 		 * frames, not on Ethernet frames.
1912 		 */
1913 		gen_and(b0, b1);
1914 
1915 		/*
1916 		 * Now add the check for Ethernet_II frames, and
1917 		 * do that before checking for the other frame
1918 		 * types.
1919 		 */
1920 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
1921 		gen_or(b0, b1);
1922 		return b1;
1923 
1924 	case ETHERTYPE_ATALK:
1925 	case ETHERTYPE_AARP:
1926 		/*
1927 		 * EtherTalk (AppleTalk protocols on Ethernet link
1928 		 * layer) may use 802.2 encapsulation.
1929 		 */
1930 
1931 		/*
1932 		 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1933 		 * we check for an Ethernet type field less than
1934 		 * 1500, which means it's an 802.3 length field.
1935 		 */
1936 		b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1937 		gen_not(b0);
1938 
1939 		/*
1940 		 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1941 		 * SNAP packets with an organization code of
1942 		 * 0x080007 (Apple, for Appletalk) and a protocol
1943 		 * type of ETHERTYPE_ATALK (Appletalk).
1944 		 *
1945 		 * 802.2-encapsulated ETHERTYPE_AARP packets are
1946 		 * SNAP packets with an organization code of
1947 		 * 0x000000 (encapsulated Ethernet) and a protocol
1948 		 * type of ETHERTYPE_AARP (Appletalk ARP).
1949 		 */
1950 		if (proto == ETHERTYPE_ATALK)
1951 			b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
1952 		else	/* proto == ETHERTYPE_AARP */
1953 			b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
1954 		gen_and(b0, b1);
1955 
1956 		/*
1957 		 * Check for Ethernet encapsulation (Ethertalk
1958 		 * phase 1?); we just check for the Ethernet
1959 		 * protocol type.
1960 		 */
1961 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
1962 
1963 		gen_or(b0, b1);
1964 		return b1;
1965 
1966 	default:
1967 		if (proto <= ETHERMTU) {
1968 			/*
1969 			 * This is an LLC SAP value, so the frames
1970 			 * that match would be 802.2 frames.
1971 			 * Check that the frame is an 802.2 frame
1972 			 * (i.e., that the length/type field is
1973 			 * a length field, <= ETHERMTU) and
1974 			 * then check the DSAP.
1975 			 */
1976 			b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1977 			gen_not(b0);
1978 			b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, (bpf_int32)proto);
1979 			gen_and(b0, b1);
1980 			return b1;
1981 		} else {
1982 			/*
1983 			 * This is an Ethernet type, so compare
1984 			 * the length/type field with it (if
1985 			 * the frame is an 802.2 frame, the length
1986 			 * field will be <= ETHERMTU, and, as
1987 			 * "proto" is > ETHERMTU, this test
1988 			 * will fail and the frame won't match,
1989 			 * which is what we want).
1990 			 */
1991 			return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
1992 			    (bpf_int32)proto);
1993 		}
1994 	}
1995 }
1996 
1997 static struct block *
gen_loopback_linktype(compiler_state_t * cstate,int proto)1998 gen_loopback_linktype(compiler_state_t *cstate, int proto)
1999 {
2000 	/*
2001 	 * For DLT_NULL, the link-layer header is a 32-bit word
2002 	 * containing an AF_ value in *host* byte order, and for
2003 	 * DLT_ENC, the link-layer header begins with a 32-bit
2004 	 * word containing an AF_ value in host byte order.
2005 	 *
2006 	 * In addition, if we're reading a saved capture file,
2007 	 * the host byte order in the capture may not be the
2008 	 * same as the host byte order on this machine.
2009 	 *
2010 	 * For DLT_LOOP, the link-layer header is a 32-bit
2011 	 * word containing an AF_ value in *network* byte order.
2012 	 */
2013 	if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) {
2014 		/*
2015 		 * The AF_ value is in host byte order, but the BPF
2016 		 * interpreter will convert it to network byte order.
2017 		 *
2018 		 * If this is a save file, and it's from a machine
2019 		 * with the opposite byte order to ours, we byte-swap
2020 		 * the AF_ value.
2021 		 *
2022 		 * Then we run it through "htonl()", and generate
2023 		 * code to compare against the result.
2024 		 */
2025 		if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped)
2026 			proto = SWAPLONG(proto);
2027 		proto = htonl(proto);
2028 	}
2029 	return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, (bpf_int32)proto));
2030 }
2031 
2032 /*
2033  * "proto" is an Ethernet type value and for IPNET, if it is not IPv4
2034  * or IPv6 then we have an error.
2035  */
2036 static struct block *
gen_ipnet_linktype(compiler_state_t * cstate,int proto)2037 gen_ipnet_linktype(compiler_state_t *cstate, int proto)
2038 {
2039 	switch (proto) {
2040 
2041 	case ETHERTYPE_IP:
2042 		return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, (bpf_int32)IPH_AF_INET);
2043 		/* NOTREACHED */
2044 
2045 	case ETHERTYPE_IPV6:
2046 		return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
2047 		    (bpf_int32)IPH_AF_INET6);
2048 		/* NOTREACHED */
2049 
2050 	default:
2051 		break;
2052 	}
2053 
2054 	return gen_false(cstate);
2055 }
2056 
2057 /*
2058  * Generate code to match a particular packet type.
2059  *
2060  * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2061  * value, if <= ETHERMTU.  We use that to determine whether to
2062  * match the type field or to check the type field for the special
2063  * LINUX_SLL_P_802_2 value and then do the appropriate test.
2064  */
2065 static struct block *
gen_linux_sll_linktype(compiler_state_t * cstate,int proto)2066 gen_linux_sll_linktype(compiler_state_t *cstate, int proto)
2067 {
2068 	struct block *b0, *b1;
2069 
2070 	switch (proto) {
2071 
2072 	case LLCSAP_ISONS:
2073 	case LLCSAP_IP:
2074 	case LLCSAP_NETBEUI:
2075 		/*
2076 		 * OSI protocols and NetBEUI always use 802.2 encapsulation,
2077 		 * so we check the DSAP and SSAP.
2078 		 *
2079 		 * LLCSAP_IP checks for IP-over-802.2, rather
2080 		 * than IP-over-Ethernet or IP-over-SNAP.
2081 		 *
2082 		 * XXX - should we check both the DSAP and the
2083 		 * SSAP, like this, or should we check just the
2084 		 * DSAP, as we do for other types <= ETHERMTU
2085 		 * (i.e., other SAP values)?
2086 		 */
2087 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2088 		b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
2089 			     ((proto << 8) | proto));
2090 		gen_and(b0, b1);
2091 		return b1;
2092 
2093 	case LLCSAP_IPX:
2094 		/*
2095 		 *	Ethernet_II frames, which are Ethernet
2096 		 *	frames with a frame type of ETHERTYPE_IPX;
2097 		 *
2098 		 *	Ethernet_802.3 frames, which have a frame
2099 		 *	type of LINUX_SLL_P_802_3;
2100 		 *
2101 		 *	Ethernet_802.2 frames, which are 802.3
2102 		 *	frames with an 802.2 LLC header (i.e, have
2103 		 *	a frame type of LINUX_SLL_P_802_2) and
2104 		 *	with the IPX LSAP as the DSAP in the LLC
2105 		 *	header;
2106 		 *
2107 		 *	Ethernet_SNAP frames, which are 802.3
2108 		 *	frames with an LLC header and a SNAP
2109 		 *	header and with an OUI of 0x000000
2110 		 *	(encapsulated Ethernet) and a protocol
2111 		 *	ID of ETHERTYPE_IPX in the SNAP header.
2112 		 *
2113 		 * First, do the checks on LINUX_SLL_P_802_2
2114 		 * frames; generate the check for either
2115 		 * Ethernet_802.2 or Ethernet_SNAP frames, and
2116 		 * then put a check for LINUX_SLL_P_802_2 frames
2117 		 * before it.
2118 		 */
2119 		b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
2120 		b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
2121 		gen_or(b0, b1);
2122 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2123 		gen_and(b0, b1);
2124 
2125 		/*
2126 		 * Now check for 802.3 frames and OR that with
2127 		 * the previous test.
2128 		 */
2129 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3);
2130 		gen_or(b0, b1);
2131 
2132 		/*
2133 		 * Now add the check for Ethernet_II frames, and
2134 		 * do that before checking for the other frame
2135 		 * types.
2136 		 */
2137 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
2138 		gen_or(b0, b1);
2139 		return b1;
2140 
2141 	case ETHERTYPE_ATALK:
2142 	case ETHERTYPE_AARP:
2143 		/*
2144 		 * EtherTalk (AppleTalk protocols on Ethernet link
2145 		 * layer) may use 802.2 encapsulation.
2146 		 */
2147 
2148 		/*
2149 		 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2150 		 * we check for the 802.2 protocol type in the
2151 		 * "Ethernet type" field.
2152 		 */
2153 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2154 
2155 		/*
2156 		 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2157 		 * SNAP packets with an organization code of
2158 		 * 0x080007 (Apple, for Appletalk) and a protocol
2159 		 * type of ETHERTYPE_ATALK (Appletalk).
2160 		 *
2161 		 * 802.2-encapsulated ETHERTYPE_AARP packets are
2162 		 * SNAP packets with an organization code of
2163 		 * 0x000000 (encapsulated Ethernet) and a protocol
2164 		 * type of ETHERTYPE_AARP (Appletalk ARP).
2165 		 */
2166 		if (proto == ETHERTYPE_ATALK)
2167 			b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
2168 		else	/* proto == ETHERTYPE_AARP */
2169 			b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
2170 		gen_and(b0, b1);
2171 
2172 		/*
2173 		 * Check for Ethernet encapsulation (Ethertalk
2174 		 * phase 1?); we just check for the Ethernet
2175 		 * protocol type.
2176 		 */
2177 		b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2178 
2179 		gen_or(b0, b1);
2180 		return b1;
2181 
2182 	default:
2183 		if (proto <= ETHERMTU) {
2184 			/*
2185 			 * This is an LLC SAP value, so the frames
2186 			 * that match would be 802.2 frames.
2187 			 * Check for the 802.2 protocol type
2188 			 * in the "Ethernet type" field, and
2189 			 * then check the DSAP.
2190 			 */
2191 			b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2192 			b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B,
2193 			     (bpf_int32)proto);
2194 			gen_and(b0, b1);
2195 			return b1;
2196 		} else {
2197 			/*
2198 			 * This is an Ethernet type, so compare
2199 			 * the length/type field with it (if
2200 			 * the frame is an 802.2 frame, the length
2201 			 * field will be <= ETHERMTU, and, as
2202 			 * "proto" is > ETHERMTU, this test
2203 			 * will fail and the frame won't match,
2204 			 * which is what we want).
2205 			 */
2206 			return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2207 		}
2208 	}
2209 }
2210 
2211 static struct slist *
gen_load_prism_llprefixlen(compiler_state_t * cstate)2212 gen_load_prism_llprefixlen(compiler_state_t *cstate)
2213 {
2214 	struct slist *s1, *s2;
2215 	struct slist *sjeq_avs_cookie;
2216 	struct slist *sjcommon;
2217 
2218 	/*
2219 	 * This code is not compatible with the optimizer, as
2220 	 * we are generating jmp instructions within a normal
2221 	 * slist of instructions
2222 	 */
2223 	cstate->no_optimize = 1;
2224 
2225 	/*
2226 	 * Generate code to load the length of the radio header into
2227 	 * the register assigned to hold that length, if one has been
2228 	 * assigned.  (If one hasn't been assigned, no code we've
2229 	 * generated uses that prefix, so we don't need to generate any
2230 	 * code to load it.)
2231 	 *
2232 	 * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
2233 	 * or always use the AVS header rather than the Prism header.
2234 	 * We load a 4-byte big-endian value at the beginning of the
2235 	 * raw packet data, and see whether, when masked with 0xFFFFF000,
2236 	 * it's equal to 0x80211000.  If so, that indicates that it's
2237 	 * an AVS header (the masked-out bits are the version number).
2238 	 * Otherwise, it's a Prism header.
2239 	 *
2240 	 * XXX - the Prism header is also, in theory, variable-length,
2241 	 * but no known software generates headers that aren't 144
2242 	 * bytes long.
2243 	 */
2244 	if (cstate->off_linkhdr.reg != -1) {
2245 		/*
2246 		 * Load the cookie.
2247 		 */
2248 		s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2249 		s1->s.k = 0;
2250 
2251 		/*
2252 		 * AND it with 0xFFFFF000.
2253 		 */
2254 		s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
2255 		s2->s.k = 0xFFFFF000;
2256 		sappend(s1, s2);
2257 
2258 		/*
2259 		 * Compare with 0x80211000.
2260 		 */
2261 		sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ));
2262 		sjeq_avs_cookie->s.k = 0x80211000;
2263 		sappend(s1, sjeq_avs_cookie);
2264 
2265 		/*
2266 		 * If it's AVS:
2267 		 *
2268 		 * The 4 bytes at an offset of 4 from the beginning of
2269 		 * the AVS header are the length of the AVS header.
2270 		 * That field is big-endian.
2271 		 */
2272 		s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2273 		s2->s.k = 4;
2274 		sappend(s1, s2);
2275 		sjeq_avs_cookie->s.jt = s2;
2276 
2277 		/*
2278 		 * Now jump to the code to allocate a register
2279 		 * into which to save the header length and
2280 		 * store the length there.  (The "jump always"
2281 		 * instruction needs to have the k field set;
2282 		 * it's added to the PC, so, as we're jumping
2283 		 * over a single instruction, it should be 1.)
2284 		 */
2285 		sjcommon = new_stmt(cstate, JMP(BPF_JA));
2286 		sjcommon->s.k = 1;
2287 		sappend(s1, sjcommon);
2288 
2289 		/*
2290 		 * Now for the code that handles the Prism header.
2291 		 * Just load the length of the Prism header (144)
2292 		 * into the A register.  Have the test for an AVS
2293 		 * header branch here if we don't have an AVS header.
2294 		 */
2295 		s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2296 		s2->s.k = 144;
2297 		sappend(s1, s2);
2298 		sjeq_avs_cookie->s.jf = s2;
2299 
2300 		/*
2301 		 * Now allocate a register to hold that value and store
2302 		 * it.  The code for the AVS header will jump here after
2303 		 * loading the length of the AVS header.
2304 		 */
2305 		s2 = new_stmt(cstate, BPF_ST);
2306 		s2->s.k = cstate->off_linkhdr.reg;
2307 		sappend(s1, s2);
2308 		sjcommon->s.jf = s2;
2309 
2310 		/*
2311 		 * Now move it into the X register.
2312 		 */
2313 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2314 		sappend(s1, s2);
2315 
2316 		return (s1);
2317 	} else
2318 		return (NULL);
2319 }
2320 
2321 static struct slist *
gen_load_avs_llprefixlen(compiler_state_t * cstate)2322 gen_load_avs_llprefixlen(compiler_state_t *cstate)
2323 {
2324 	struct slist *s1, *s2;
2325 
2326 	/*
2327 	 * Generate code to load the length of the AVS header into
2328 	 * the register assigned to hold that length, if one has been
2329 	 * assigned.  (If one hasn't been assigned, no code we've
2330 	 * generated uses that prefix, so we don't need to generate any
2331 	 * code to load it.)
2332 	 */
2333 	if (cstate->off_linkhdr.reg != -1) {
2334 		/*
2335 		 * The 4 bytes at an offset of 4 from the beginning of
2336 		 * the AVS header are the length of the AVS header.
2337 		 * That field is big-endian.
2338 		 */
2339 		s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2340 		s1->s.k = 4;
2341 
2342 		/*
2343 		 * Now allocate a register to hold that value and store
2344 		 * it.
2345 		 */
2346 		s2 = new_stmt(cstate, BPF_ST);
2347 		s2->s.k = cstate->off_linkhdr.reg;
2348 		sappend(s1, s2);
2349 
2350 		/*
2351 		 * Now move it into the X register.
2352 		 */
2353 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2354 		sappend(s1, s2);
2355 
2356 		return (s1);
2357 	} else
2358 		return (NULL);
2359 }
2360 
2361 static struct slist *
gen_load_radiotap_llprefixlen(compiler_state_t * cstate)2362 gen_load_radiotap_llprefixlen(compiler_state_t *cstate)
2363 {
2364 	struct slist *s1, *s2;
2365 
2366 	/*
2367 	 * Generate code to load the length of the radiotap header into
2368 	 * the register assigned to hold that length, if one has been
2369 	 * assigned.  (If one hasn't been assigned, no code we've
2370 	 * generated uses that prefix, so we don't need to generate any
2371 	 * code to load it.)
2372 	 */
2373 	if (cstate->off_linkhdr.reg != -1) {
2374 		/*
2375 		 * The 2 bytes at offsets of 2 and 3 from the beginning
2376 		 * of the radiotap header are the length of the radiotap
2377 		 * header; unfortunately, it's little-endian, so we have
2378 		 * to load it a byte at a time and construct the value.
2379 		 */
2380 
2381 		/*
2382 		 * Load the high-order byte, at an offset of 3, shift it
2383 		 * left a byte, and put the result in the X register.
2384 		 */
2385 		s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2386 		s1->s.k = 3;
2387 		s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2388 		sappend(s1, s2);
2389 		s2->s.k = 8;
2390 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2391 		sappend(s1, s2);
2392 
2393 		/*
2394 		 * Load the next byte, at an offset of 2, and OR the
2395 		 * value from the X register into it.
2396 		 */
2397 		s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2398 		sappend(s1, s2);
2399 		s2->s.k = 2;
2400 		s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2401 		sappend(s1, s2);
2402 
2403 		/*
2404 		 * Now allocate a register to hold that value and store
2405 		 * it.
2406 		 */
2407 		s2 = new_stmt(cstate, BPF_ST);
2408 		s2->s.k = cstate->off_linkhdr.reg;
2409 		sappend(s1, s2);
2410 
2411 		/*
2412 		 * Now move it into the X register.
2413 		 */
2414 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2415 		sappend(s1, s2);
2416 
2417 		return (s1);
2418 	} else
2419 		return (NULL);
2420 }
2421 
2422 /*
2423  * At the moment we treat PPI as normal Radiotap encoded
2424  * packets. The difference is in the function that generates
2425  * the code at the beginning to compute the header length.
2426  * Since this code generator of PPI supports bare 802.11
2427  * encapsulation only (i.e. the encapsulated DLT should be
2428  * DLT_IEEE802_11) we generate code to check for this too;
2429  * that's done in finish_parse().
2430  */
2431 static struct slist *
gen_load_ppi_llprefixlen(compiler_state_t * cstate)2432 gen_load_ppi_llprefixlen(compiler_state_t *cstate)
2433 {
2434 	struct slist *s1, *s2;
2435 
2436 	/*
2437 	 * Generate code to load the length of the radiotap header
2438 	 * into the register assigned to hold that length, if one has
2439 	 * been assigned.
2440 	 */
2441 	if (cstate->off_linkhdr.reg != -1) {
2442 		/*
2443 		 * The 2 bytes at offsets of 2 and 3 from the beginning
2444 		 * of the radiotap header are the length of the radiotap
2445 		 * header; unfortunately, it's little-endian, so we have
2446 		 * to load it a byte at a time and construct the value.
2447 		 */
2448 
2449 		/*
2450 		 * Load the high-order byte, at an offset of 3, shift it
2451 		 * left a byte, and put the result in the X register.
2452 		 */
2453 		s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2454 		s1->s.k = 3;
2455 		s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2456 		sappend(s1, s2);
2457 		s2->s.k = 8;
2458 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2459 		sappend(s1, s2);
2460 
2461 		/*
2462 		 * Load the next byte, at an offset of 2, and OR the
2463 		 * value from the X register into it.
2464 		 */
2465 		s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2466 		sappend(s1, s2);
2467 		s2->s.k = 2;
2468 		s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2469 		sappend(s1, s2);
2470 
2471 		/*
2472 		 * Now allocate a register to hold that value and store
2473 		 * it.
2474 		 */
2475 		s2 = new_stmt(cstate, BPF_ST);
2476 		s2->s.k = cstate->off_linkhdr.reg;
2477 		sappend(s1, s2);
2478 
2479 		/*
2480 		 * Now move it into the X register.
2481 		 */
2482 		s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2483 		sappend(s1, s2);
2484 
2485 		return (s1);
2486 	} else
2487 		return (NULL);
2488 }
2489 
2490 /*
2491  * Load a value relative to the beginning of the link-layer header after the 802.11
2492  * header, i.e. LLC_SNAP.
2493  * The link-layer header doesn't necessarily begin at the beginning
2494  * of the packet data; there might be a variable-length prefix containing
2495  * radio information.
2496  */
2497 static struct slist *
gen_load_802_11_header_len(compiler_state_t * cstate,struct slist * s,struct slist * snext)2498 gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext)
2499 {
2500 	struct slist *s2;
2501 	struct slist *sjset_data_frame_1;
2502 	struct slist *sjset_data_frame_2;
2503 	struct slist *sjset_qos;
2504 	struct slist *sjset_radiotap_flags_present;
2505 	struct slist *sjset_radiotap_ext_present;
2506 	struct slist *sjset_radiotap_tsft_present;
2507 	struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
2508 	struct slist *s_roundup;
2509 
2510 	if (cstate->off_linkpl.reg == -1) {
2511 		/*
2512 		 * No register has been assigned to the offset of
2513 		 * the link-layer payload, which means nobody needs
2514 		 * it; don't bother computing it - just return
2515 		 * what we already have.
2516 		 */
2517 		return (s);
2518 	}
2519 
2520 	/*
2521 	 * This code is not compatible with the optimizer, as
2522 	 * we are generating jmp instructions within a normal
2523 	 * slist of instructions
2524 	 */
2525 	cstate->no_optimize = 1;
2526 
2527 	/*
2528 	 * If "s" is non-null, it has code to arrange that the X register
2529 	 * contains the length of the prefix preceding the link-layer
2530 	 * header.
2531 	 *
2532 	 * Otherwise, the length of the prefix preceding the link-layer
2533 	 * header is "off_outermostlinkhdr.constant_part".
2534 	 */
2535 	if (s == NULL) {
2536 		/*
2537 		 * There is no variable-length header preceding the
2538 		 * link-layer header.
2539 		 *
2540 		 * Load the length of the fixed-length prefix preceding
2541 		 * the link-layer header (if any) into the X register,
2542 		 * and store it in the cstate->off_linkpl.reg register.
2543 		 * That length is off_outermostlinkhdr.constant_part.
2544 		 */
2545 		s = new_stmt(cstate, BPF_LDX|BPF_IMM);
2546 		s->s.k = cstate->off_outermostlinkhdr.constant_part;
2547 	}
2548 
2549 	/*
2550 	 * The X register contains the offset of the beginning of the
2551 	 * link-layer header; add 24, which is the minimum length
2552 	 * of the MAC header for a data frame, to that, and store it
2553 	 * in cstate->off_linkpl.reg, and then load the Frame Control field,
2554 	 * which is at the offset in the X register, with an indexed load.
2555 	 */
2556 	s2 = new_stmt(cstate, BPF_MISC|BPF_TXA);
2557 	sappend(s, s2);
2558 	s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
2559 	s2->s.k = 24;
2560 	sappend(s, s2);
2561 	s2 = new_stmt(cstate, BPF_ST);
2562 	s2->s.k = cstate->off_linkpl.reg;
2563 	sappend(s, s2);
2564 
2565 	s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
2566 	s2->s.k = 0;
2567 	sappend(s, s2);
2568 
2569 	/*
2570 	 * Check the Frame Control field to see if this is a data frame;
2571 	 * a data frame has the 0x08 bit (b3) in that field set and the
2572 	 * 0x04 bit (b2) clear.
2573 	 */
2574 	sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET));
2575 	sjset_data_frame_1->s.k = 0x08;
2576 	sappend(s, sjset_data_frame_1);
2577 
2578 	/*
2579 	 * If b3 is set, test b2, otherwise go to the first statement of
2580 	 * the rest of the program.
2581 	 */
2582 	sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET));
2583 	sjset_data_frame_2->s.k = 0x04;
2584 	sappend(s, sjset_data_frame_2);
2585 	sjset_data_frame_1->s.jf = snext;
2586 
2587 	/*
2588 	 * If b2 is not set, this is a data frame; test the QoS bit.
2589 	 * Otherwise, go to the first statement of the rest of the
2590 	 * program.
2591 	 */
2592 	sjset_data_frame_2->s.jt = snext;
2593 	sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET));
2594 	sjset_qos->s.k = 0x80;	/* QoS bit */
2595 	sappend(s, sjset_qos);
2596 
2597 	/*
2598 	 * If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS
2599 	 * field.
2600 	 * Otherwise, go to the first statement of the rest of the
2601 	 * program.
2602 	 */
2603 	sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
2604 	s2->s.k = cstate->off_linkpl.reg;
2605 	sappend(s, s2);
2606 	s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2607 	s2->s.k = 2;
2608 	sappend(s, s2);
2609 	s2 = new_stmt(cstate, BPF_ST);
2610 	s2->s.k = cstate->off_linkpl.reg;
2611 	sappend(s, s2);
2612 
2613 	/*
2614 	 * If we have a radiotap header, look at it to see whether
2615 	 * there's Atheros padding between the MAC-layer header
2616 	 * and the payload.
2617 	 *
2618 	 * Note: all of the fields in the radiotap header are
2619 	 * little-endian, so we byte-swap all of the values
2620 	 * we test against, as they will be loaded as big-endian
2621 	 * values.
2622 	 *
2623 	 * XXX - in the general case, we would have to scan through
2624 	 * *all* the presence bits, if there's more than one word of
2625 	 * presence bits.  That would require a loop, meaning that
2626 	 * we wouldn't be able to run the filter in the kernel.
2627 	 *
2628 	 * We assume here that the Atheros adapters that insert the
2629 	 * annoying padding don't have multiple antennae and therefore
2630 	 * do not generate radiotap headers with multiple presence words.
2631 	 */
2632 	if (cstate->linktype == DLT_IEEE802_11_RADIO) {
2633 		/*
2634 		 * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
2635 		 * in the first presence flag word?
2636 		 */
2637 		sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W);
2638 		s2->s.k = 4;
2639 		sappend(s, s2);
2640 
2641 		sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET));
2642 		sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002);
2643 		sappend(s, sjset_radiotap_flags_present);
2644 
2645 		/*
2646 		 * If not, skip all of this.
2647 		 */
2648 		sjset_radiotap_flags_present->s.jf = snext;
2649 
2650 		/*
2651 		 * Otherwise, is the "extension" bit set in that word?
2652 		 */
2653 		sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET));
2654 		sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000);
2655 		sappend(s, sjset_radiotap_ext_present);
2656 		sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present;
2657 
2658 		/*
2659 		 * If so, skip all of this.
2660 		 */
2661 		sjset_radiotap_ext_present->s.jt = snext;
2662 
2663 		/*
2664 		 * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
2665 		 */
2666 		sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET));
2667 		sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001);
2668 		sappend(s, sjset_radiotap_tsft_present);
2669 		sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present;
2670 
2671 		/*
2672 		 * If IEEE80211_RADIOTAP_TSFT is set, the flags field is
2673 		 * at an offset of 16 from the beginning of the raw packet
2674 		 * data (8 bytes for the radiotap header and 8 bytes for
2675 		 * the TSFT field).
2676 		 *
2677 		 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2678 		 * is set.
2679 		 */
2680 		s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2681 		s2->s.k = 16;
2682 		sappend(s, s2);
2683 		sjset_radiotap_tsft_present->s.jt = s2;
2684 
2685 		sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2686 		sjset_tsft_datapad->s.k = 0x20;
2687 		sappend(s, sjset_tsft_datapad);
2688 
2689 		/*
2690 		 * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
2691 		 * at an offset of 8 from the beginning of the raw packet
2692 		 * data (8 bytes for the radiotap header).
2693 		 *
2694 		 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2695 		 * is set.
2696 		 */
2697 		s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2698 		s2->s.k = 8;
2699 		sappend(s, s2);
2700 		sjset_radiotap_tsft_present->s.jf = s2;
2701 
2702 		sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2703 		sjset_notsft_datapad->s.k = 0x20;
2704 		sappend(s, sjset_notsft_datapad);
2705 
2706 		/*
2707 		 * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
2708 		 * set, round the length of the 802.11 header to
2709 		 * a multiple of 4.  Do that by adding 3 and then
2710 		 * dividing by and multiplying by 4, which we do by
2711 		 * ANDing with ~3.
2712 		 */
2713 		s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM);
2714 		s_roundup->s.k = cstate->off_linkpl.reg;
2715 		sappend(s, s_roundup);
2716 		s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2717 		s2->s.k = 3;
2718 		sappend(s, s2);
2719 		s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM);
2720 		s2->s.k = ~3;
2721 		sappend(s, s2);
2722 		s2 = new_stmt(cstate, BPF_ST);
2723 		s2->s.k = cstate->off_linkpl.reg;
2724 		sappend(s, s2);
2725 
2726 		sjset_tsft_datapad->s.jt = s_roundup;
2727 		sjset_tsft_datapad->s.jf = snext;
2728 		sjset_notsft_datapad->s.jt = s_roundup;
2729 		sjset_notsft_datapad->s.jf = snext;
2730 	} else
2731 		sjset_qos->s.jf = snext;
2732 
2733 	return s;
2734 }
2735 
2736 static void
insert_compute_vloffsets(compiler_state_t * cstate,struct block * b)2737 insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
2738 {
2739 	struct slist *s;
2740 
2741 	/* There is an implicit dependency between the link
2742 	 * payload and link header since the payload computation
2743 	 * includes the variable part of the header. Therefore,
2744 	 * if nobody else has allocated a register for the link
2745 	 * header and we need it, do it now. */
2746 	if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable &&
2747 	    cstate->off_linkhdr.reg == -1)
2748 		cstate->off_linkhdr.reg = alloc_reg(cstate);
2749 
2750 	/*
2751 	 * For link-layer types that have a variable-length header
2752 	 * preceding the link-layer header, generate code to load
2753 	 * the offset of the link-layer header into the register
2754 	 * assigned to that offset, if any.
2755 	 *
2756 	 * XXX - this, and the next switch statement, won't handle
2757 	 * encapsulation of 802.11 or 802.11+radio information in
2758 	 * some other protocol stack.  That's significantly more
2759 	 * complicated.
2760 	 */
2761 	switch (cstate->outermostlinktype) {
2762 
2763 	case DLT_PRISM_HEADER:
2764 		s = gen_load_prism_llprefixlen(cstate);
2765 		break;
2766 
2767 	case DLT_IEEE802_11_RADIO_AVS:
2768 		s = gen_load_avs_llprefixlen(cstate);
2769 		break;
2770 
2771 	case DLT_IEEE802_11_RADIO:
2772 		s = gen_load_radiotap_llprefixlen(cstate);
2773 		break;
2774 
2775 	case DLT_PPI:
2776 		s = gen_load_ppi_llprefixlen(cstate);
2777 		break;
2778 
2779 	default:
2780 		s = NULL;
2781 		break;
2782 	}
2783 
2784 	/*
2785 	 * For link-layer types that have a variable-length link-layer
2786 	 * header, generate code to load the offset of the link-layer
2787 	 * payload into the register assigned to that offset, if any.
2788 	 */
2789 	switch (cstate->outermostlinktype) {
2790 
2791 	case DLT_IEEE802_11:
2792 	case DLT_PRISM_HEADER:
2793 	case DLT_IEEE802_11_RADIO_AVS:
2794 	case DLT_IEEE802_11_RADIO:
2795 	case DLT_PPI:
2796 		s = gen_load_802_11_header_len(cstate, s, b->stmts);
2797 		break;
2798 	}
2799 
2800 	/*
2801 	 * If we have any offset-loading code, append all the
2802 	 * existing statements in the block to those statements,
2803 	 * and make the resulting list the list of statements
2804 	 * for the block.
2805 	 */
2806 	if (s != NULL) {
2807 		sappend(s, b->stmts);
2808 		b->stmts = s;
2809 	}
2810 }
2811 
2812 static struct block *
gen_ppi_dlt_check(compiler_state_t * cstate)2813 gen_ppi_dlt_check(compiler_state_t *cstate)
2814 {
2815 	struct slist *s_load_dlt;
2816 	struct block *b;
2817 
2818 	if (cstate->linktype == DLT_PPI)
2819 	{
2820 		/* Create the statements that check for the DLT
2821 		 */
2822 		s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2823 		s_load_dlt->s.k = 4;
2824 
2825 		b = new_block(cstate, JMP(BPF_JEQ));
2826 
2827 		b->stmts = s_load_dlt;
2828 		b->s.k = SWAPLONG(DLT_IEEE802_11);
2829 	}
2830 	else
2831 	{
2832 		b = NULL;
2833 	}
2834 
2835 	return b;
2836 }
2837 
2838 /*
2839  * Take an absolute offset, and:
2840  *
2841  *    if it has no variable part, return NULL;
2842  *
2843  *    if it has a variable part, generate code to load the register
2844  *    containing that variable part into the X register, returning
2845  *    a pointer to that code - if no register for that offset has
2846  *    been allocated, allocate it first.
2847  *
2848  * (The code to set that register will be generated later, but will
2849  * be placed earlier in the code sequence.)
2850  */
2851 static struct slist *
gen_abs_offset_varpart(compiler_state_t * cstate,bpf_abs_offset * off)2852 gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off)
2853 {
2854 	struct slist *s;
2855 
2856 	if (off->is_variable) {
2857 		if (off->reg == -1) {
2858 			/*
2859 			 * We haven't yet assigned a register for the
2860 			 * variable part of the offset of the link-layer
2861 			 * header; allocate one.
2862 			 */
2863 			off->reg = alloc_reg(cstate);
2864 		}
2865 
2866 		/*
2867 		 * Load the register containing the variable part of the
2868 		 * offset of the link-layer header into the X register.
2869 		 */
2870 		s = new_stmt(cstate, BPF_LDX|BPF_MEM);
2871 		s->s.k = off->reg;
2872 		return s;
2873 	} else {
2874 		/*
2875 		 * That offset isn't variable, there's no variable part,
2876 		 * so we don't need to generate any code.
2877 		 */
2878 		return NULL;
2879 	}
2880 }
2881 
2882 /*
2883  * Map an Ethernet type to the equivalent PPP type.
2884  */
2885 static int
ethertype_to_ppptype(proto)2886 ethertype_to_ppptype(proto)
2887 	int proto;
2888 {
2889 	switch (proto) {
2890 
2891 	case ETHERTYPE_IP:
2892 		proto = PPP_IP;
2893 		break;
2894 
2895 	case ETHERTYPE_IPV6:
2896 		proto = PPP_IPV6;
2897 		break;
2898 
2899 	case ETHERTYPE_DN:
2900 		proto = PPP_DECNET;
2901 		break;
2902 
2903 	case ETHERTYPE_ATALK:
2904 		proto = PPP_APPLE;
2905 		break;
2906 
2907 	case ETHERTYPE_NS:
2908 		proto = PPP_NS;
2909 		break;
2910 
2911 	case LLCSAP_ISONS:
2912 		proto = PPP_OSI;
2913 		break;
2914 
2915 	case LLCSAP_8021D:
2916 		/*
2917 		 * I'm assuming the "Bridging PDU"s that go
2918 		 * over PPP are Spanning Tree Protocol
2919 		 * Bridging PDUs.
2920 		 */
2921 		proto = PPP_BRPDU;
2922 		break;
2923 
2924 	case LLCSAP_IPX:
2925 		proto = PPP_IPX;
2926 		break;
2927 	}
2928 	return (proto);
2929 }
2930 
2931 /*
2932  * Generate any tests that, for encapsulation of a link-layer packet
2933  * inside another protocol stack, need to be done to check for those
2934  * link-layer packets (and that haven't already been done by a check
2935  * for that encapsulation).
2936  */
2937 static struct block *
gen_prevlinkhdr_check(compiler_state_t * cstate)2938 gen_prevlinkhdr_check(compiler_state_t *cstate)
2939 {
2940 	struct block *b0;
2941 
2942 	if (cstate->is_geneve)
2943 		return gen_geneve_ll_check(cstate);
2944 
2945 	switch (cstate->prevlinktype) {
2946 
2947 	case DLT_SUNATM:
2948 		/*
2949 		 * This is LANE-encapsulated Ethernet; check that the LANE
2950 		 * packet doesn't begin with an LE Control marker, i.e.
2951 		 * that it's data, not a control message.
2952 		 *
2953 		 * (We've already generated a test for LANE.)
2954 		 */
2955 		b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00);
2956 		gen_not(b0);
2957 		return b0;
2958 
2959 	default:
2960 		/*
2961 		 * No such tests are necessary.
2962 		 */
2963 		return NULL;
2964 	}
2965 	/*NOTREACHED*/
2966 }
2967 
2968 /*
2969  * The three different values we should check for when checking for an
2970  * IPv6 packet with DLT_NULL.
2971  */
2972 #define BSD_AFNUM_INET6_BSD	24	/* NetBSD, OpenBSD, BSD/OS, Npcap */
2973 #define BSD_AFNUM_INET6_FREEBSD	28	/* FreeBSD */
2974 #define BSD_AFNUM_INET6_DARWIN	30	/* OS X, iOS, other Darwin-based OSes */
2975 
2976 /*
2977  * Generate code to match a particular packet type by matching the
2978  * link-layer type field or fields in the 802.2 LLC header.
2979  *
2980  * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2981  * value, if <= ETHERMTU.
2982  */
2983 static struct block *
gen_linktype(compiler_state_t * cstate,int proto)2984 gen_linktype(compiler_state_t *cstate, int proto)
2985 {
2986 	struct block *b0, *b1, *b2;
2987 	const char *description;
2988 
2989 	/* are we checking MPLS-encapsulated packets? */
2990 	if (cstate->label_stack_depth > 0) {
2991 		switch (proto) {
2992 		case ETHERTYPE_IP:
2993 		case PPP_IP:
2994 			/* FIXME add other L3 proto IDs */
2995 			return gen_mpls_linktype(cstate, Q_IP);
2996 
2997 		case ETHERTYPE_IPV6:
2998 		case PPP_IPV6:
2999 			/* FIXME add other L3 proto IDs */
3000 			return gen_mpls_linktype(cstate, Q_IPV6);
3001 
3002 		default:
3003 			bpf_error(cstate, "unsupported protocol over mpls");
3004 			/* NOTREACHED */
3005 		}
3006 	}
3007 
3008 	switch (cstate->linktype) {
3009 
3010 	case DLT_EN10MB:
3011 	case DLT_NETANALYZER:
3012 	case DLT_NETANALYZER_TRANSPARENT:
3013 		/* Geneve has an EtherType regardless of whether there is an
3014 		 * L2 header. */
3015 		if (!cstate->is_geneve)
3016 			b0 = gen_prevlinkhdr_check(cstate);
3017 		else
3018 			b0 = NULL;
3019 
3020 		b1 = gen_ether_linktype(cstate, proto);
3021 		if (b0 != NULL)
3022 			gen_and(b0, b1);
3023 		return b1;
3024 		/*NOTREACHED*/
3025 		break;
3026 
3027 	case DLT_C_HDLC:
3028 		switch (proto) {
3029 
3030 		case LLCSAP_ISONS:
3031 			proto = (proto << 8 | LLCSAP_ISONS);
3032 			/* fall through */
3033 
3034 		default:
3035 			return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3036 			/*NOTREACHED*/
3037 			break;
3038 		}
3039 		break;
3040 
3041 	case DLT_IEEE802_11:
3042 	case DLT_PRISM_HEADER:
3043 	case DLT_IEEE802_11_RADIO_AVS:
3044 	case DLT_IEEE802_11_RADIO:
3045 	case DLT_PPI:
3046 		/*
3047 		 * Check that we have a data frame.
3048 		 */
3049 		b0 = gen_check_802_11_data_frame(cstate);
3050 
3051 		/*
3052 		 * Now check for the specified link-layer type.
3053 		 */
3054 		b1 = gen_llc_linktype(cstate, proto);
3055 		gen_and(b0, b1);
3056 		return b1;
3057 		/*NOTREACHED*/
3058 		break;
3059 
3060 	case DLT_FDDI:
3061 		/*
3062 		 * XXX - check for LLC frames.
3063 		 */
3064 		return gen_llc_linktype(cstate, proto);
3065 		/*NOTREACHED*/
3066 		break;
3067 
3068 	case DLT_IEEE802:
3069 		/*
3070 		 * XXX - check for LLC PDUs, as per IEEE 802.5.
3071 		 */
3072 		return gen_llc_linktype(cstate, proto);
3073 		/*NOTREACHED*/
3074 		break;
3075 
3076 	case DLT_ATM_RFC1483:
3077 	case DLT_ATM_CLIP:
3078 	case DLT_IP_OVER_FC:
3079 		return gen_llc_linktype(cstate, proto);
3080 		/*NOTREACHED*/
3081 		break;
3082 
3083 	case DLT_SUNATM:
3084 		/*
3085 		 * Check for an LLC-encapsulated version of this protocol;
3086 		 * if we were checking for LANE, linktype would no longer
3087 		 * be DLT_SUNATM.
3088 		 *
3089 		 * Check for LLC encapsulation and then check the protocol.
3090 		 */
3091 		b0 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
3092 		b1 = gen_llc_linktype(cstate, proto);
3093 		gen_and(b0, b1);
3094 		return b1;
3095 		/*NOTREACHED*/
3096 		break;
3097 
3098 	case DLT_LINUX_SLL:
3099 		return gen_linux_sll_linktype(cstate, proto);
3100 		/*NOTREACHED*/
3101 		break;
3102 
3103 	case DLT_SLIP:
3104 	case DLT_SLIP_BSDOS:
3105 	case DLT_RAW:
3106 		/*
3107 		 * These types don't provide any type field; packets
3108 		 * are always IPv4 or IPv6.
3109 		 *
3110 		 * XXX - for IPv4, check for a version number of 4, and,
3111 		 * for IPv6, check for a version number of 6?
3112 		 */
3113 		switch (proto) {
3114 
3115 		case ETHERTYPE_IP:
3116 			/* Check for a version number of 4. */
3117 			return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0);
3118 
3119 		case ETHERTYPE_IPV6:
3120 			/* Check for a version number of 6. */
3121 			return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0);
3122 
3123 		default:
3124 			return gen_false(cstate);	/* always false */
3125 		}
3126 		/*NOTREACHED*/
3127 		break;
3128 
3129 	case DLT_IPV4:
3130 		/*
3131 		 * Raw IPv4, so no type field.
3132 		 */
3133 		if (proto == ETHERTYPE_IP)
3134 			return gen_true(cstate);	/* always true */
3135 
3136 		/* Checking for something other than IPv4; always false */
3137 		return gen_false(cstate);
3138 		/*NOTREACHED*/
3139 		break;
3140 
3141 	case DLT_IPV6:
3142 		/*
3143 		 * Raw IPv6, so no type field.
3144 		 */
3145 		if (proto == ETHERTYPE_IPV6)
3146 			return gen_true(cstate);	/* always true */
3147 
3148 		/* Checking for something other than IPv6; always false */
3149 		return gen_false(cstate);
3150 		/*NOTREACHED*/
3151 		break;
3152 
3153 	case DLT_PPP:
3154 	case DLT_PPP_PPPD:
3155 	case DLT_PPP_SERIAL:
3156 	case DLT_PPP_ETHER:
3157 		/*
3158 		 * We use Ethernet protocol types inside libpcap;
3159 		 * map them to the corresponding PPP protocol types.
3160 		 */
3161 		proto = ethertype_to_ppptype(proto);
3162 		return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3163 		/*NOTREACHED*/
3164 		break;
3165 
3166 	case DLT_PPP_BSDOS:
3167 		/*
3168 		 * We use Ethernet protocol types inside libpcap;
3169 		 * map them to the corresponding PPP protocol types.
3170 		 */
3171 		switch (proto) {
3172 
3173 		case ETHERTYPE_IP:
3174 			/*
3175 			 * Also check for Van Jacobson-compressed IP.
3176 			 * XXX - do this for other forms of PPP?
3177 			 */
3178 			b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP);
3179 			b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC);
3180 			gen_or(b0, b1);
3181 			b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC);
3182 			gen_or(b1, b0);
3183 			return b0;
3184 
3185 		default:
3186 			proto = ethertype_to_ppptype(proto);
3187 			return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
3188 				(bpf_int32)proto);
3189 		}
3190 		/*NOTREACHED*/
3191 		break;
3192 
3193 	case DLT_NULL:
3194 	case DLT_LOOP:
3195 	case DLT_ENC:
3196 		switch (proto) {
3197 
3198 		case ETHERTYPE_IP:
3199 			return (gen_loopback_linktype(cstate, AF_INET));
3200 
3201 		case ETHERTYPE_IPV6:
3202 			/*
3203 			 * AF_ values may, unfortunately, be platform-
3204 			 * dependent; AF_INET isn't, because everybody
3205 			 * used 4.2BSD's value, but AF_INET6 is, because
3206 			 * 4.2BSD didn't have a value for it (given that
3207 			 * IPv6 didn't exist back in the early 1980's),
3208 			 * and they all picked their own values.
3209 			 *
3210 			 * This means that, if we're reading from a
3211 			 * savefile, we need to check for all the
3212 			 * possible values.
3213 			 *
3214 			 * If we're doing a live capture, we only need
3215 			 * to check for this platform's value; however,
3216 			 * Npcap uses 24, which isn't Windows's AF_INET6
3217 			 * value.  (Given the multiple different values,
3218 			 * programs that read pcap files shouldn't be
3219 			 * checking for their platform's AF_INET6 value
3220 			 * anyway, they should check for all of the
3221 			 * possible values. and they might as well do
3222 			 * that even for live captures.)
3223 			 */
3224 			if (cstate->bpf_pcap->rfile != NULL) {
3225 				/*
3226 				 * Savefile - check for all three
3227 				 * possible IPv6 values.
3228 				 */
3229 				b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD);
3230 				b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD);
3231 				gen_or(b0, b1);
3232 				b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN);
3233 				gen_or(b0, b1);
3234 				return (b1);
3235 			} else {
3236 				/*
3237 				 * Live capture, so we only need to
3238 				 * check for the value used on this
3239 				 * platform.
3240 				 */
3241 #ifdef _WIN32
3242 				/*
3243 				 * Npcap doesn't use Windows's AF_INET6,
3244 				 * as that collides with AF_IPX on
3245 				 * some BSDs (both have the value 23).
3246 				 * Instead, it uses 24.
3247 				 */
3248 				return (gen_loopback_linktype(cstate, 24));
3249 #else /* _WIN32 */
3250 #ifdef AF_INET6
3251 				return (gen_loopback_linktype(cstate, AF_INET6));
3252 #else /* AF_INET6 */
3253 				/*
3254 				 * I guess this platform doesn't support
3255 				 * IPv6, so we just reject all packets.
3256 				 */
3257 				return gen_false(cstate);
3258 #endif /* AF_INET6 */
3259 #endif /* _WIN32 */
3260 			}
3261 
3262 		default:
3263 			/*
3264 			 * Not a type on which we support filtering.
3265 			 * XXX - support those that have AF_ values
3266 			 * #defined on this platform, at least?
3267 			 */
3268 			return gen_false(cstate);
3269 		}
3270 
3271 #ifdef HAVE_NET_PFVAR_H
3272 	case DLT_PFLOG:
3273 		/*
3274 		 * af field is host byte order in contrast to the rest of
3275 		 * the packet.
3276 		 */
3277 		if (proto == ETHERTYPE_IP)
3278 			return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3279 			    BPF_B, (bpf_int32)AF_INET));
3280 		else if (proto == ETHERTYPE_IPV6)
3281 			return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3282 			    BPF_B, (bpf_int32)AF_INET6));
3283 		else
3284 			return gen_false(cstate);
3285 		/*NOTREACHED*/
3286 		break;
3287 #endif /* HAVE_NET_PFVAR_H */
3288 
3289 	case DLT_ARCNET:
3290 	case DLT_ARCNET_LINUX:
3291 		/*
3292 		 * XXX should we check for first fragment if the protocol
3293 		 * uses PHDS?
3294 		 */
3295 		switch (proto) {
3296 
3297 		default:
3298 			return gen_false(cstate);
3299 
3300 		case ETHERTYPE_IPV6:
3301 			return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3302 				(bpf_int32)ARCTYPE_INET6));
3303 
3304 		case ETHERTYPE_IP:
3305 			b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3306 				     (bpf_int32)ARCTYPE_IP);
3307 			b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3308 				     (bpf_int32)ARCTYPE_IP_OLD);
3309 			gen_or(b0, b1);
3310 			return (b1);
3311 
3312 		case ETHERTYPE_ARP:
3313 			b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3314 				     (bpf_int32)ARCTYPE_ARP);
3315 			b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3316 				     (bpf_int32)ARCTYPE_ARP_OLD);
3317 			gen_or(b0, b1);
3318 			return (b1);
3319 
3320 		case ETHERTYPE_REVARP:
3321 			return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3322 					(bpf_int32)ARCTYPE_REVARP));
3323 
3324 		case ETHERTYPE_ATALK:
3325 			return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3326 					(bpf_int32)ARCTYPE_ATALK));
3327 		}
3328 		/*NOTREACHED*/
3329 		break;
3330 
3331 	case DLT_LTALK:
3332 		switch (proto) {
3333 		case ETHERTYPE_ATALK:
3334 			return gen_true(cstate);
3335 		default:
3336 			return gen_false(cstate);
3337 		}
3338 		/*NOTREACHED*/
3339 		break;
3340 
3341 	case DLT_FRELAY:
3342 		/*
3343 		 * XXX - assumes a 2-byte Frame Relay header with
3344 		 * DLCI and flags.  What if the address is longer?
3345 		 */
3346 		switch (proto) {
3347 
3348 		case ETHERTYPE_IP:
3349 			/*
3350 			 * Check for the special NLPID for IP.
3351 			 */
3352 			return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc);
3353 
3354 		case ETHERTYPE_IPV6:
3355 			/*
3356 			 * Check for the special NLPID for IPv6.
3357 			 */
3358 			return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e);
3359 
3360 		case LLCSAP_ISONS:
3361 			/*
3362 			 * Check for several OSI protocols.
3363 			 *
3364 			 * Frame Relay packets typically have an OSI
3365 			 * NLPID at the beginning; we check for each
3366 			 * of them.
3367 			 *
3368 			 * What we check for is the NLPID and a frame
3369 			 * control field of UI, i.e. 0x03 followed
3370 			 * by the NLPID.
3371 			 */
3372 			b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
3373 			b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
3374 			b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
3375 			gen_or(b1, b2);
3376 			gen_or(b0, b2);
3377 			return b2;
3378 
3379 		default:
3380 			return gen_false(cstate);
3381 		}
3382 		/*NOTREACHED*/
3383 		break;
3384 
3385 	case DLT_MFR:
3386 		bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented");
3387 
3388         case DLT_JUNIPER_MFR:
3389         case DLT_JUNIPER_MLFR:
3390         case DLT_JUNIPER_MLPPP:
3391 	case DLT_JUNIPER_ATM1:
3392 	case DLT_JUNIPER_ATM2:
3393 	case DLT_JUNIPER_PPPOE:
3394 	case DLT_JUNIPER_PPPOE_ATM:
3395         case DLT_JUNIPER_GGSN:
3396         case DLT_JUNIPER_ES:
3397         case DLT_JUNIPER_MONITOR:
3398         case DLT_JUNIPER_SERVICES:
3399         case DLT_JUNIPER_ETHER:
3400         case DLT_JUNIPER_PPP:
3401         case DLT_JUNIPER_FRELAY:
3402         case DLT_JUNIPER_CHDLC:
3403         case DLT_JUNIPER_VP:
3404         case DLT_JUNIPER_ST:
3405         case DLT_JUNIPER_ISM:
3406         case DLT_JUNIPER_VS:
3407         case DLT_JUNIPER_SRX_E2E:
3408         case DLT_JUNIPER_FIBRECHANNEL:
3409 	case DLT_JUNIPER_ATM_CEMIC:
3410 
3411 		/* just lets verify the magic number for now -
3412 		 * on ATM we may have up to 6 different encapsulations on the wire
3413 		 * and need a lot of heuristics to figure out that the payload
3414 		 * might be;
3415 		 *
3416 		 * FIXME encapsulation specific BPF_ filters
3417 		 */
3418 		return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
3419 
3420 	case DLT_BACNET_MS_TP:
3421 		return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000);
3422 
3423 	case DLT_IPNET:
3424 		return gen_ipnet_linktype(cstate, proto);
3425 
3426 	case DLT_LINUX_IRDA:
3427 		bpf_error(cstate, "IrDA link-layer type filtering not implemented");
3428 
3429 	case DLT_DOCSIS:
3430 		bpf_error(cstate, "DOCSIS link-layer type filtering not implemented");
3431 
3432 	case DLT_MTP2:
3433 	case DLT_MTP2_WITH_PHDR:
3434 		bpf_error(cstate, "MTP2 link-layer type filtering not implemented");
3435 
3436 	case DLT_ERF:
3437 		bpf_error(cstate, "ERF link-layer type filtering not implemented");
3438 
3439 	case DLT_PFSYNC:
3440 		bpf_error(cstate, "PFSYNC link-layer type filtering not implemented");
3441 
3442 	case DLT_LINUX_LAPD:
3443 		bpf_error(cstate, "LAPD link-layer type filtering not implemented");
3444 
3445 	case DLT_USB_FREEBSD:
3446 	case DLT_USB_LINUX:
3447 	case DLT_USB_LINUX_MMAPPED:
3448 	case DLT_USBPCAP:
3449 		bpf_error(cstate, "USB link-layer type filtering not implemented");
3450 
3451 	case DLT_BLUETOOTH_HCI_H4:
3452 	case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
3453 		bpf_error(cstate, "Bluetooth link-layer type filtering not implemented");
3454 
3455 	case DLT_CAN20B:
3456 	case DLT_CAN_SOCKETCAN:
3457 		bpf_error(cstate, "CAN link-layer type filtering not implemented");
3458 
3459 	case DLT_IEEE802_15_4:
3460 	case DLT_IEEE802_15_4_LINUX:
3461 	case DLT_IEEE802_15_4_NONASK_PHY:
3462 	case DLT_IEEE802_15_4_NOFCS:
3463 		bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented");
3464 
3465 	case DLT_IEEE802_16_MAC_CPS_RADIO:
3466 		bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented");
3467 
3468 	case DLT_SITA:
3469 		bpf_error(cstate, "SITA link-layer type filtering not implemented");
3470 
3471 	case DLT_RAIF1:
3472 		bpf_error(cstate, "RAIF1 link-layer type filtering not implemented");
3473 
3474 	case DLT_IPMB:
3475 		bpf_error(cstate, "IPMB link-layer type filtering not implemented");
3476 
3477 	case DLT_AX25_KISS:
3478 		bpf_error(cstate, "AX.25 link-layer type filtering not implemented");
3479 
3480 	case DLT_NFLOG:
3481 		/* Using the fixed-size NFLOG header it is possible to tell only
3482 		 * the address family of the packet, other meaningful data is
3483 		 * either missing or behind TLVs.
3484 		 */
3485 		bpf_error(cstate, "NFLOG link-layer type filtering not implemented");
3486 
3487 	default:
3488 		/*
3489 		 * Does this link-layer header type have a field
3490 		 * indicating the type of the next protocol?  If
3491 		 * so, off_linktype.constant_part will be the offset of that
3492 		 * field in the packet; if not, it will be OFFSET_NOT_SET.
3493 		 */
3494 		if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) {
3495 			/*
3496 			 * Yes; assume it's an Ethernet type.  (If
3497 			 * it's not, it needs to be handled specially
3498 			 * above.)
3499 			 */
3500 			return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3501 		} else {
3502 			/*
3503 			 * No; report an error.
3504 			 */
3505 			description = pcap_datalink_val_to_description(cstate->linktype);
3506 			if (description != NULL) {
3507 				bpf_error(cstate, "%s link-layer type filtering not implemented",
3508 				    description);
3509 			} else {
3510 				bpf_error(cstate, "DLT %u link-layer type filtering not implemented",
3511 				    cstate->linktype);
3512 			}
3513 		}
3514 		break;
3515 	}
3516 }
3517 
3518 /*
3519  * Check for an LLC SNAP packet with a given organization code and
3520  * protocol type; we check the entire contents of the 802.2 LLC and
3521  * snap headers, checking for DSAP and SSAP of SNAP and a control
3522  * field of 0x03 in the LLC header, and for the specified organization
3523  * code and protocol type in the SNAP header.
3524  */
3525 static struct block *
gen_snap(compiler_state_t * cstate,bpf_u_int32 orgcode,bpf_u_int32 ptype)3526 gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype)
3527 {
3528 	u_char snapblock[8];
3529 
3530 	snapblock[0] = LLCSAP_SNAP;	/* DSAP = SNAP */
3531 	snapblock[1] = LLCSAP_SNAP;	/* SSAP = SNAP */
3532 	snapblock[2] = 0x03;		/* control = UI */
3533 	snapblock[3] = (orgcode >> 16);	/* upper 8 bits of organization code */
3534 	snapblock[4] = (orgcode >> 8);	/* middle 8 bits of organization code */
3535 	snapblock[5] = (orgcode >> 0);	/* lower 8 bits of organization code */
3536 	snapblock[6] = (ptype >> 8);	/* upper 8 bits of protocol type */
3537 	snapblock[7] = (ptype >> 0);	/* lower 8 bits of protocol type */
3538 	return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock);
3539 }
3540 
3541 /*
3542  * Generate code to match frames with an LLC header.
3543  */
3544 struct block *
gen_llc(compiler_state_t * cstate)3545 gen_llc(compiler_state_t *cstate)
3546 {
3547 	struct block *b0, *b1;
3548 
3549 	switch (cstate->linktype) {
3550 
3551 	case DLT_EN10MB:
3552 		/*
3553 		 * We check for an Ethernet type field less than
3554 		 * 1500, which means it's an 802.3 length field.
3555 		 */
3556 		b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
3557 		gen_not(b0);
3558 
3559 		/*
3560 		 * Now check for the purported DSAP and SSAP not being
3561 		 * 0xFF, to rule out NetWare-over-802.3.
3562 		 */
3563 		b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
3564 		gen_not(b1);
3565 		gen_and(b0, b1);
3566 		return b1;
3567 
3568 	case DLT_SUNATM:
3569 		/*
3570 		 * We check for LLC traffic.
3571 		 */
3572 		b0 = gen_atmtype_abbrev(cstate, A_LLC);
3573 		return b0;
3574 
3575 	case DLT_IEEE802:	/* Token Ring */
3576 		/*
3577 		 * XXX - check for LLC frames.
3578 		 */
3579 		return gen_true(cstate);
3580 
3581 	case DLT_FDDI:
3582 		/*
3583 		 * XXX - check for LLC frames.
3584 		 */
3585 		return gen_true(cstate);
3586 
3587 	case DLT_ATM_RFC1483:
3588 		/*
3589 		 * For LLC encapsulation, these are defined to have an
3590 		 * 802.2 LLC header.
3591 		 *
3592 		 * For VC encapsulation, they don't, but there's no
3593 		 * way to check for that; the protocol used on the VC
3594 		 * is negotiated out of band.
3595 		 */
3596 		return gen_true(cstate);
3597 
3598 	case DLT_IEEE802_11:
3599 	case DLT_PRISM_HEADER:
3600 	case DLT_IEEE802_11_RADIO:
3601 	case DLT_IEEE802_11_RADIO_AVS:
3602 	case DLT_PPI:
3603 		/*
3604 		 * Check that we have a data frame.
3605 		 */
3606 		b0 = gen_check_802_11_data_frame(cstate);
3607 		return b0;
3608 
3609 	default:
3610 		bpf_error(cstate, "'llc' not supported for linktype %d", cstate->linktype);
3611 		/* NOTREACHED */
3612 	}
3613 }
3614 
3615 struct block *
gen_llc_i(compiler_state_t * cstate)3616 gen_llc_i(compiler_state_t *cstate)
3617 {
3618 	struct block *b0, *b1;
3619 	struct slist *s;
3620 
3621 	/*
3622 	 * Check whether this is an LLC frame.
3623 	 */
3624 	b0 = gen_llc(cstate);
3625 
3626 	/*
3627 	 * Load the control byte and test the low-order bit; it must
3628 	 * be clear for I frames.
3629 	 */
3630 	s = gen_load_a(cstate, OR_LLC, 2, BPF_B);
3631 	b1 = new_block(cstate, JMP(BPF_JSET));
3632 	b1->s.k = 0x01;
3633 	b1->stmts = s;
3634 	gen_not(b1);
3635 	gen_and(b0, b1);
3636 	return b1;
3637 }
3638 
3639 struct block *
gen_llc_s(compiler_state_t * cstate)3640 gen_llc_s(compiler_state_t *cstate)
3641 {
3642 	struct block *b0, *b1;
3643 
3644 	/*
3645 	 * Check whether this is an LLC frame.
3646 	 */
3647 	b0 = gen_llc(cstate);
3648 
3649 	/*
3650 	 * Now compare the low-order 2 bit of the control byte against
3651 	 * the appropriate value for S frames.
3652 	 */
3653 	b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03);
3654 	gen_and(b0, b1);
3655 	return b1;
3656 }
3657 
3658 struct block *
gen_llc_u(compiler_state_t * cstate)3659 gen_llc_u(compiler_state_t *cstate)
3660 {
3661 	struct block *b0, *b1;
3662 
3663 	/*
3664 	 * Check whether this is an LLC frame.
3665 	 */
3666 	b0 = gen_llc(cstate);
3667 
3668 	/*
3669 	 * Now compare the low-order 2 bit of the control byte against
3670 	 * the appropriate value for U frames.
3671 	 */
3672 	b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03);
3673 	gen_and(b0, b1);
3674 	return b1;
3675 }
3676 
3677 struct block *
gen_llc_s_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3678 gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3679 {
3680 	struct block *b0, *b1;
3681 
3682 	/*
3683 	 * Check whether this is an LLC frame.
3684 	 */
3685 	b0 = gen_llc(cstate);
3686 
3687 	/*
3688 	 * Now check for an S frame with the appropriate type.
3689 	 */
3690 	b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK);
3691 	gen_and(b0, b1);
3692 	return b1;
3693 }
3694 
3695 struct block *
gen_llc_u_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3696 gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3697 {
3698 	struct block *b0, *b1;
3699 
3700 	/*
3701 	 * Check whether this is an LLC frame.
3702 	 */
3703 	b0 = gen_llc(cstate);
3704 
3705 	/*
3706 	 * Now check for a U frame with the appropriate type.
3707 	 */
3708 	b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK);
3709 	gen_and(b0, b1);
3710 	return b1;
3711 }
3712 
3713 /*
3714  * Generate code to match a particular packet type, for link-layer types
3715  * using 802.2 LLC headers.
3716  *
3717  * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
3718  * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
3719  *
3720  * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3721  * value, if <= ETHERMTU.  We use that to determine whether to
3722  * match the DSAP or both DSAP and LSAP or to check the OUI and
3723  * protocol ID in a SNAP header.
3724  */
3725 static struct block *
gen_llc_linktype(compiler_state_t * cstate,int proto)3726 gen_llc_linktype(compiler_state_t *cstate, int proto)
3727 {
3728 	/*
3729 	 * XXX - handle token-ring variable-length header.
3730 	 */
3731 	switch (proto) {
3732 
3733 	case LLCSAP_IP:
3734 	case LLCSAP_ISONS:
3735 	case LLCSAP_NETBEUI:
3736 		/*
3737 		 * XXX - should we check both the DSAP and the
3738 		 * SSAP, like this, or should we check just the
3739 		 * DSAP, as we do for other SAP values?
3740 		 */
3741 		return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32)
3742 			     ((proto << 8) | proto));
3743 
3744 	case LLCSAP_IPX:
3745 		/*
3746 		 * XXX - are there ever SNAP frames for IPX on
3747 		 * non-Ethernet 802.x networks?
3748 		 */
3749 		return gen_cmp(cstate, OR_LLC, 0, BPF_B,
3750 		    (bpf_int32)LLCSAP_IPX);
3751 
3752 	case ETHERTYPE_ATALK:
3753 		/*
3754 		 * 802.2-encapsulated ETHERTYPE_ATALK packets are
3755 		 * SNAP packets with an organization code of
3756 		 * 0x080007 (Apple, for Appletalk) and a protocol
3757 		 * type of ETHERTYPE_ATALK (Appletalk).
3758 		 *
3759 		 * XXX - check for an organization code of
3760 		 * encapsulated Ethernet as well?
3761 		 */
3762 		return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
3763 
3764 	default:
3765 		/*
3766 		 * XXX - we don't have to check for IPX 802.3
3767 		 * here, but should we check for the IPX Ethertype?
3768 		 */
3769 		if (proto <= ETHERMTU) {
3770 			/*
3771 			 * This is an LLC SAP value, so check
3772 			 * the DSAP.
3773 			 */
3774 			return gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)proto);
3775 		} else {
3776 			/*
3777 			 * This is an Ethernet type; we assume that it's
3778 			 * unlikely that it'll appear in the right place
3779 			 * at random, and therefore check only the
3780 			 * location that would hold the Ethernet type
3781 			 * in a SNAP frame with an organization code of
3782 			 * 0x000000 (encapsulated Ethernet).
3783 			 *
3784 			 * XXX - if we were to check for the SNAP DSAP and
3785 			 * LSAP, as per XXX, and were also to check for an
3786 			 * organization code of 0x000000 (encapsulated
3787 			 * Ethernet), we'd do
3788 			 *
3789 			 *	return gen_snap(cstate, 0x000000, proto);
3790 			 *
3791 			 * here; for now, we don't, as per the above.
3792 			 * I don't know whether it's worth the extra CPU
3793 			 * time to do the right check or not.
3794 			 */
3795 			return gen_cmp(cstate, OR_LLC, 6, BPF_H, (bpf_int32)proto);
3796 		}
3797 	}
3798 }
3799 
3800 static struct block *
gen_hostop(compiler_state_t * cstate,bpf_u_int32 addr,bpf_u_int32 mask,int dir,int proto,u_int src_off,u_int dst_off)3801 gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
3802     int dir, int proto, u_int src_off, u_int dst_off)
3803 {
3804 	struct block *b0, *b1;
3805 	u_int offset;
3806 
3807 	switch (dir) {
3808 
3809 	case Q_SRC:
3810 		offset = src_off;
3811 		break;
3812 
3813 	case Q_DST:
3814 		offset = dst_off;
3815 		break;
3816 
3817 	case Q_AND:
3818 		b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3819 		b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3820 		gen_and(b0, b1);
3821 		return b1;
3822 
3823 	case Q_OR:
3824 	case Q_DEFAULT:
3825 		b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3826 		b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3827 		gen_or(b0, b1);
3828 		return b1;
3829 
3830 	default:
3831 		abort();
3832 	}
3833 	b0 = gen_linktype(cstate, proto);
3834 	b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, (bpf_int32)addr, mask);
3835 	gen_and(b0, b1);
3836 	return b1;
3837 }
3838 
3839 #ifdef INET6
3840 static struct block *
gen_hostop6(compiler_state_t * cstate,struct in6_addr * addr,struct in6_addr * mask,int dir,int proto,u_int src_off,u_int dst_off)3841 gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
3842     struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off)
3843 {
3844 	struct block *b0, *b1;
3845 	u_int offset;
3846 	u_int32_t *a, *m;
3847 
3848 	switch (dir) {
3849 
3850 	case Q_SRC:
3851 		offset = src_off;
3852 		break;
3853 
3854 	case Q_DST:
3855 		offset = dst_off;
3856 		break;
3857 
3858 	case Q_AND:
3859 		b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3860 		b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3861 		gen_and(b0, b1);
3862 		return b1;
3863 
3864 	case Q_OR:
3865 	case Q_DEFAULT:
3866 		b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3867 		b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3868 		gen_or(b0, b1);
3869 		return b1;
3870 
3871 	default:
3872 		abort();
3873 	}
3874 	/* this order is important */
3875 	a = (u_int32_t *)addr;
3876 	m = (u_int32_t *)mask;
3877 	b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
3878 	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
3879 	gen_and(b0, b1);
3880 	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
3881 	gen_and(b0, b1);
3882 	b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
3883 	gen_and(b0, b1);
3884 	b0 = gen_linktype(cstate, proto);
3885 	gen_and(b0, b1);
3886 	return b1;
3887 }
3888 #endif
3889 
3890 static struct block *
gen_ehostop(compiler_state_t * cstate,const u_char * eaddr,int dir)3891 gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
3892 {
3893 	register struct block *b0, *b1;
3894 
3895 	switch (dir) {
3896 	case Q_SRC:
3897 		return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
3898 
3899 	case Q_DST:
3900 		return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
3901 
3902 	case Q_AND:
3903 		b0 = gen_ehostop(cstate, eaddr, Q_SRC);
3904 		b1 = gen_ehostop(cstate, eaddr, Q_DST);
3905 		gen_and(b0, b1);
3906 		return b1;
3907 
3908 	case Q_DEFAULT:
3909 	case Q_OR:
3910 		b0 = gen_ehostop(cstate, eaddr, Q_SRC);
3911 		b1 = gen_ehostop(cstate, eaddr, Q_DST);
3912 		gen_or(b0, b1);
3913 		return b1;
3914 
3915 	case Q_ADDR1:
3916 		bpf_error(cstate, "'addr1' is only supported on 802.11 with 802.11 headers");
3917 		break;
3918 
3919 	case Q_ADDR2:
3920 		bpf_error(cstate, "'addr2' is only supported on 802.11 with 802.11 headers");
3921 		break;
3922 
3923 	case Q_ADDR3:
3924 		bpf_error(cstate, "'addr3' is only supported on 802.11 with 802.11 headers");
3925 		break;
3926 
3927 	case Q_ADDR4:
3928 		bpf_error(cstate, "'addr4' is only supported on 802.11 with 802.11 headers");
3929 		break;
3930 
3931 	case Q_RA:
3932 		bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers");
3933 		break;
3934 
3935 	case Q_TA:
3936 		bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers");
3937 		break;
3938 	}
3939 	abort();
3940 	/* NOTREACHED */
3941 }
3942 
3943 /*
3944  * Like gen_ehostop, but for DLT_FDDI
3945  */
3946 static struct block *
gen_fhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)3947 gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
3948 {
3949 	struct block *b0, *b1;
3950 
3951 	switch (dir) {
3952 	case Q_SRC:
3953 		return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
3954 
3955 	case Q_DST:
3956 		return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
3957 
3958 	case Q_AND:
3959 		b0 = gen_fhostop(cstate, eaddr, Q_SRC);
3960 		b1 = gen_fhostop(cstate, eaddr, Q_DST);
3961 		gen_and(b0, b1);
3962 		return b1;
3963 
3964 	case Q_DEFAULT:
3965 	case Q_OR:
3966 		b0 = gen_fhostop(cstate, eaddr, Q_SRC);
3967 		b1 = gen_fhostop(cstate, eaddr, Q_DST);
3968 		gen_or(b0, b1);
3969 		return b1;
3970 
3971 	case Q_ADDR1:
3972 		bpf_error(cstate, "'addr1' is only supported on 802.11");
3973 		break;
3974 
3975 	case Q_ADDR2:
3976 		bpf_error(cstate, "'addr2' is only supported on 802.11");
3977 		break;
3978 
3979 	case Q_ADDR3:
3980 		bpf_error(cstate, "'addr3' is only supported on 802.11");
3981 		break;
3982 
3983 	case Q_ADDR4:
3984 		bpf_error(cstate, "'addr4' is only supported on 802.11");
3985 		break;
3986 
3987 	case Q_RA:
3988 		bpf_error(cstate, "'ra' is only supported on 802.11");
3989 		break;
3990 
3991 	case Q_TA:
3992 		bpf_error(cstate, "'ta' is only supported on 802.11");
3993 		break;
3994 	}
3995 	abort();
3996 	/* NOTREACHED */
3997 }
3998 
3999 /*
4000  * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
4001  */
4002 static struct block *
gen_thostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4003 gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4004 {
4005 	register struct block *b0, *b1;
4006 
4007 	switch (dir) {
4008 	case Q_SRC:
4009 		return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
4010 
4011 	case Q_DST:
4012 		return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4013 
4014 	case Q_AND:
4015 		b0 = gen_thostop(cstate, eaddr, Q_SRC);
4016 		b1 = gen_thostop(cstate, eaddr, Q_DST);
4017 		gen_and(b0, b1);
4018 		return b1;
4019 
4020 	case Q_DEFAULT:
4021 	case Q_OR:
4022 		b0 = gen_thostop(cstate, eaddr, Q_SRC);
4023 		b1 = gen_thostop(cstate, eaddr, Q_DST);
4024 		gen_or(b0, b1);
4025 		return b1;
4026 
4027 	case Q_ADDR1:
4028 		bpf_error(cstate, "'addr1' is only supported on 802.11");
4029 		break;
4030 
4031 	case Q_ADDR2:
4032 		bpf_error(cstate, "'addr2' is only supported on 802.11");
4033 		break;
4034 
4035 	case Q_ADDR3:
4036 		bpf_error(cstate, "'addr3' is only supported on 802.11");
4037 		break;
4038 
4039 	case Q_ADDR4:
4040 		bpf_error(cstate, "'addr4' is only supported on 802.11");
4041 		break;
4042 
4043 	case Q_RA:
4044 		bpf_error(cstate, "'ra' is only supported on 802.11");
4045 		break;
4046 
4047 	case Q_TA:
4048 		bpf_error(cstate, "'ta' is only supported on 802.11");
4049 		break;
4050 	}
4051 	abort();
4052 	/* NOTREACHED */
4053 }
4054 
4055 /*
4056  * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
4057  * various 802.11 + radio headers.
4058  */
4059 static struct block *
gen_wlanhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4060 gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4061 {
4062 	register struct block *b0, *b1, *b2;
4063 	register struct slist *s;
4064 
4065 #ifdef ENABLE_WLAN_FILTERING_PATCH
4066 	/*
4067 	 * TODO GV 20070613
4068 	 * We need to disable the optimizer because the optimizer is buggy
4069 	 * and wipes out some LD instructions generated by the below
4070 	 * code to validate the Frame Control bits
4071 	 */
4072 	cstate->no_optimize = 1;
4073 #endif /* ENABLE_WLAN_FILTERING_PATCH */
4074 
4075 	switch (dir) {
4076 	case Q_SRC:
4077 		/*
4078 		 * Oh, yuk.
4079 		 *
4080 		 *	For control frames, there is no SA.
4081 		 *
4082 		 *	For management frames, SA is at an
4083 		 *	offset of 10 from the beginning of
4084 		 *	the packet.
4085 		 *
4086 		 *	For data frames, SA is at an offset
4087 		 *	of 10 from the beginning of the packet
4088 		 *	if From DS is clear, at an offset of
4089 		 *	16 from the beginning of the packet
4090 		 *	if From DS is set and To DS is clear,
4091 		 *	and an offset of 24 from the beginning
4092 		 *	of the packet if From DS is set and To DS
4093 		 *	is set.
4094 		 */
4095 
4096 		/*
4097 		 * Generate the tests to be done for data frames
4098 		 * with From DS set.
4099 		 *
4100 		 * First, check for To DS set, i.e. check "link[1] & 0x01".
4101 		 */
4102 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4103 		b1 = new_block(cstate, JMP(BPF_JSET));
4104 		b1->s.k = 0x01;	/* To DS */
4105 		b1->stmts = s;
4106 
4107 		/*
4108 		 * If To DS is set, the SA is at 24.
4109 		 */
4110 		b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4111 		gen_and(b1, b0);
4112 
4113 		/*
4114 		 * Now, check for To DS not set, i.e. check
4115 		 * "!(link[1] & 0x01)".
4116 		 */
4117 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4118 		b2 = new_block(cstate, JMP(BPF_JSET));
4119 		b2->s.k = 0x01;	/* To DS */
4120 		b2->stmts = s;
4121 		gen_not(b2);
4122 
4123 		/*
4124 		 * If To DS is not set, the SA is at 16.
4125 		 */
4126 		b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4127 		gen_and(b2, b1);
4128 
4129 		/*
4130 		 * Now OR together the last two checks.  That gives
4131 		 * the complete set of checks for data frames with
4132 		 * From DS set.
4133 		 */
4134 		gen_or(b1, b0);
4135 
4136 		/*
4137 		 * Now check for From DS being set, and AND that with
4138 		 * the ORed-together checks.
4139 		 */
4140 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4141 		b1 = new_block(cstate, JMP(BPF_JSET));
4142 		b1->s.k = 0x02;	/* From DS */
4143 		b1->stmts = s;
4144 		gen_and(b1, b0);
4145 
4146 		/*
4147 		 * Now check for data frames with From DS not set.
4148 		 */
4149 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4150 		b2 = new_block(cstate, JMP(BPF_JSET));
4151 		b2->s.k = 0x02;	/* From DS */
4152 		b2->stmts = s;
4153 		gen_not(b2);
4154 
4155 		/*
4156 		 * If From DS isn't set, the SA is at 10.
4157 		 */
4158 		b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4159 		gen_and(b2, b1);
4160 
4161 		/*
4162 		 * Now OR together the checks for data frames with
4163 		 * From DS not set and for data frames with From DS
4164 		 * set; that gives the checks done for data frames.
4165 		 */
4166 		gen_or(b1, b0);
4167 
4168 		/*
4169 		 * Now check for a data frame.
4170 		 * I.e, check "link[0] & 0x08".
4171 		 */
4172 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4173 		b1 = new_block(cstate, JMP(BPF_JSET));
4174 		b1->s.k = 0x08;
4175 		b1->stmts = s;
4176 
4177 		/*
4178 		 * AND that with the checks done for data frames.
4179 		 */
4180 		gen_and(b1, b0);
4181 
4182 		/*
4183 		 * If the high-order bit of the type value is 0, this
4184 		 * is a management frame.
4185 		 * I.e, check "!(link[0] & 0x08)".
4186 		 */
4187 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4188 		b2 = new_block(cstate, JMP(BPF_JSET));
4189 		b2->s.k = 0x08;
4190 		b2->stmts = s;
4191 		gen_not(b2);
4192 
4193 		/*
4194 		 * For management frames, the SA is at 10.
4195 		 */
4196 		b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4197 		gen_and(b2, b1);
4198 
4199 		/*
4200 		 * OR that with the checks done for data frames.
4201 		 * That gives the checks done for management and
4202 		 * data frames.
4203 		 */
4204 		gen_or(b1, b0);
4205 
4206 		/*
4207 		 * If the low-order bit of the type value is 1,
4208 		 * this is either a control frame or a frame
4209 		 * with a reserved type, and thus not a
4210 		 * frame with an SA.
4211 		 *
4212 		 * I.e., check "!(link[0] & 0x04)".
4213 		 */
4214 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4215 		b1 = new_block(cstate, JMP(BPF_JSET));
4216 		b1->s.k = 0x04;
4217 		b1->stmts = s;
4218 		gen_not(b1);
4219 
4220 		/*
4221 		 * AND that with the checks for data and management
4222 		 * frames.
4223 		 */
4224 		gen_and(b1, b0);
4225 		return b0;
4226 
4227 	case Q_DST:
4228 		/*
4229 		 * Oh, yuk.
4230 		 *
4231 		 *	For control frames, there is no DA.
4232 		 *
4233 		 *	For management frames, DA is at an
4234 		 *	offset of 4 from the beginning of
4235 		 *	the packet.
4236 		 *
4237 		 *	For data frames, DA is at an offset
4238 		 *	of 4 from the beginning of the packet
4239 		 *	if To DS is clear and at an offset of
4240 		 *	16 from the beginning of the packet
4241 		 *	if To DS is set.
4242 		 */
4243 
4244 		/*
4245 		 * Generate the tests to be done for data frames.
4246 		 *
4247 		 * First, check for To DS set, i.e. "link[1] & 0x01".
4248 		 */
4249 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4250 		b1 = new_block(cstate, JMP(BPF_JSET));
4251 		b1->s.k = 0x01;	/* To DS */
4252 		b1->stmts = s;
4253 
4254 		/*
4255 		 * If To DS is set, the DA is at 16.
4256 		 */
4257 		b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4258 		gen_and(b1, b0);
4259 
4260 		/*
4261 		 * Now, check for To DS not set, i.e. check
4262 		 * "!(link[1] & 0x01)".
4263 		 */
4264 		s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4265 		b2 = new_block(cstate, JMP(BPF_JSET));
4266 		b2->s.k = 0x01;	/* To DS */
4267 		b2->stmts = s;
4268 		gen_not(b2);
4269 
4270 		/*
4271 		 * If To DS is not set, the DA is at 4.
4272 		 */
4273 		b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4274 		gen_and(b2, b1);
4275 
4276 		/*
4277 		 * Now OR together the last two checks.  That gives
4278 		 * the complete set of checks for data frames.
4279 		 */
4280 		gen_or(b1, b0);
4281 
4282 		/*
4283 		 * Now check for a data frame.
4284 		 * I.e, check "link[0] & 0x08".
4285 		 */
4286 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4287 		b1 = new_block(cstate, JMP(BPF_JSET));
4288 		b1->s.k = 0x08;
4289 		b1->stmts = s;
4290 
4291 		/*
4292 		 * AND that with the checks done for data frames.
4293 		 */
4294 		gen_and(b1, b0);
4295 
4296 		/*
4297 		 * If the high-order bit of the type value is 0, this
4298 		 * is a management frame.
4299 		 * I.e, check "!(link[0] & 0x08)".
4300 		 */
4301 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4302 		b2 = new_block(cstate, JMP(BPF_JSET));
4303 		b2->s.k = 0x08;
4304 		b2->stmts = s;
4305 		gen_not(b2);
4306 
4307 		/*
4308 		 * For management frames, the DA is at 4.
4309 		 */
4310 		b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4311 		gen_and(b2, b1);
4312 
4313 		/*
4314 		 * OR that with the checks done for data frames.
4315 		 * That gives the checks done for management and
4316 		 * data frames.
4317 		 */
4318 		gen_or(b1, b0);
4319 
4320 		/*
4321 		 * If the low-order bit of the type value is 1,
4322 		 * this is either a control frame or a frame
4323 		 * with a reserved type, and thus not a
4324 		 * frame with an SA.
4325 		 *
4326 		 * I.e., check "!(link[0] & 0x04)".
4327 		 */
4328 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4329 		b1 = new_block(cstate, JMP(BPF_JSET));
4330 		b1->s.k = 0x04;
4331 		b1->stmts = s;
4332 		gen_not(b1);
4333 
4334 		/*
4335 		 * AND that with the checks for data and management
4336 		 * frames.
4337 		 */
4338 		gen_and(b1, b0);
4339 		return b0;
4340 
4341 	case Q_RA:
4342 		/*
4343 		 * Not present in management frames; addr1 in other
4344 		 * frames.
4345 		 */
4346 
4347 		/*
4348 		 * If the high-order bit of the type value is 0, this
4349 		 * is a management frame.
4350 		 * I.e, check "(link[0] & 0x08)".
4351 		 */
4352 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4353 		b1 = new_block(cstate, JMP(BPF_JSET));
4354 		b1->s.k = 0x08;
4355 		b1->stmts = s;
4356 
4357 		/*
4358 		 * Check addr1.
4359 		 */
4360 		b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4361 
4362 		/*
4363 		 * AND that with the check of addr1.
4364 		 */
4365 		gen_and(b1, b0);
4366 		return (b0);
4367 
4368 	case Q_TA:
4369 		/*
4370 		 * Not present in management frames; addr2, if present,
4371 		 * in other frames.
4372 		 */
4373 
4374 		/*
4375 		 * Not present in CTS or ACK control frames.
4376 		 */
4377 		b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4378 			IEEE80211_FC0_TYPE_MASK);
4379 		gen_not(b0);
4380 		b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4381 			IEEE80211_FC0_SUBTYPE_MASK);
4382 		gen_not(b1);
4383 		b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4384 			IEEE80211_FC0_SUBTYPE_MASK);
4385 		gen_not(b2);
4386 		gen_and(b1, b2);
4387 		gen_or(b0, b2);
4388 
4389 		/*
4390 		 * If the high-order bit of the type value is 0, this
4391 		 * is a management frame.
4392 		 * I.e, check "(link[0] & 0x08)".
4393 		 */
4394 		s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4395 		b1 = new_block(cstate, JMP(BPF_JSET));
4396 		b1->s.k = 0x08;
4397 		b1->stmts = s;
4398 
4399 		/*
4400 		 * AND that with the check for frames other than
4401 		 * CTS and ACK frames.
4402 		 */
4403 		gen_and(b1, b2);
4404 
4405 		/*
4406 		 * Check addr2.
4407 		 */
4408 		b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4409 		gen_and(b2, b1);
4410 		return b1;
4411 
4412 	/*
4413 	 * XXX - add BSSID keyword?
4414 	 */
4415 	case Q_ADDR1:
4416 		return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr));
4417 
4418 	case Q_ADDR2:
4419 		/*
4420 		 * Not present in CTS or ACK control frames.
4421 		 */
4422 		b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4423 			IEEE80211_FC0_TYPE_MASK);
4424 		gen_not(b0);
4425 		b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4426 			IEEE80211_FC0_SUBTYPE_MASK);
4427 		gen_not(b1);
4428 		b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4429 			IEEE80211_FC0_SUBTYPE_MASK);
4430 		gen_not(b2);
4431 		gen_and(b1, b2);
4432 		gen_or(b0, b2);
4433 		b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4434 		gen_and(b2, b1);
4435 		return b1;
4436 
4437 	case Q_ADDR3:
4438 		/*
4439 		 * Not present in control frames.
4440 		 */
4441 		b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4442 			IEEE80211_FC0_TYPE_MASK);
4443 		gen_not(b0);
4444 		b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4445 		gen_and(b0, b1);
4446 		return b1;
4447 
4448 	case Q_ADDR4:
4449 		/*
4450 		 * Present only if the direction mask has both "From DS"
4451 		 * and "To DS" set.  Neither control frames nor management
4452 		 * frames should have both of those set, so we don't
4453 		 * check the frame type.
4454 		 */
4455 		b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B,
4456 			IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
4457 		b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4458 		gen_and(b0, b1);
4459 		return b1;
4460 
4461 	case Q_AND:
4462 		b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4463 		b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4464 		gen_and(b0, b1);
4465 		return b1;
4466 
4467 	case Q_DEFAULT:
4468 	case Q_OR:
4469 		b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4470 		b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4471 		gen_or(b0, b1);
4472 		return b1;
4473 	}
4474 	abort();
4475 	/* NOTREACHED */
4476 }
4477 
4478 /*
4479  * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
4480  * (We assume that the addresses are IEEE 48-bit MAC addresses,
4481  * as the RFC states.)
4482  */
4483 static struct block *
gen_ipfchostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4484 gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4485 {
4486 	register struct block *b0, *b1;
4487 
4488 	switch (dir) {
4489 	case Q_SRC:
4490 		return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4491 
4492 	case Q_DST:
4493 		return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4494 
4495 	case Q_AND:
4496 		b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4497 		b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4498 		gen_and(b0, b1);
4499 		return b1;
4500 
4501 	case Q_DEFAULT:
4502 	case Q_OR:
4503 		b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4504 		b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4505 		gen_or(b0, b1);
4506 		return b1;
4507 
4508 	case Q_ADDR1:
4509 		bpf_error(cstate, "'addr1' is only supported on 802.11");
4510 		break;
4511 
4512 	case Q_ADDR2:
4513 		bpf_error(cstate, "'addr2' is only supported on 802.11");
4514 		break;
4515 
4516 	case Q_ADDR3:
4517 		bpf_error(cstate, "'addr3' is only supported on 802.11");
4518 		break;
4519 
4520 	case Q_ADDR4:
4521 		bpf_error(cstate, "'addr4' is only supported on 802.11");
4522 		break;
4523 
4524 	case Q_RA:
4525 		bpf_error(cstate, "'ra' is only supported on 802.11");
4526 		break;
4527 
4528 	case Q_TA:
4529 		bpf_error(cstate, "'ta' is only supported on 802.11");
4530 		break;
4531 	}
4532 	abort();
4533 	/* NOTREACHED */
4534 }
4535 
4536 /*
4537  * This is quite tricky because there may be pad bytes in front of the
4538  * DECNET header, and then there are two possible data packet formats that
4539  * carry both src and dst addresses, plus 5 packet types in a format that
4540  * carries only the src node, plus 2 types that use a different format and
4541  * also carry just the src node.
4542  *
4543  * Yuck.
4544  *
4545  * Instead of doing those all right, we just look for data packets with
4546  * 0 or 1 bytes of padding.  If you want to look at other packets, that
4547  * will require a lot more hacking.
4548  *
4549  * To add support for filtering on DECNET "areas" (network numbers)
4550  * one would want to add a "mask" argument to this routine.  That would
4551  * make the filter even more inefficient, although one could be clever
4552  * and not generate masking instructions if the mask is 0xFFFF.
4553  */
4554 static struct block *
gen_dnhostop(compiler_state_t * cstate,bpf_u_int32 addr,int dir)4555 gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir)
4556 {
4557 	struct block *b0, *b1, *b2, *tmp;
4558 	u_int offset_lh;	/* offset if long header is received */
4559 	u_int offset_sh;	/* offset if short header is received */
4560 
4561 	switch (dir) {
4562 
4563 	case Q_DST:
4564 		offset_sh = 1;	/* follows flags */
4565 		offset_lh = 7;	/* flgs,darea,dsubarea,HIORD */
4566 		break;
4567 
4568 	case Q_SRC:
4569 		offset_sh = 3;	/* follows flags, dstnode */
4570 		offset_lh = 15;	/* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
4571 		break;
4572 
4573 	case Q_AND:
4574 		/* Inefficient because we do our Calvinball dance twice */
4575 		b0 = gen_dnhostop(cstate, addr, Q_SRC);
4576 		b1 = gen_dnhostop(cstate, addr, Q_DST);
4577 		gen_and(b0, b1);
4578 		return b1;
4579 
4580 	case Q_OR:
4581 	case Q_DEFAULT:
4582 		/* Inefficient because we do our Calvinball dance twice */
4583 		b0 = gen_dnhostop(cstate, addr, Q_SRC);
4584 		b1 = gen_dnhostop(cstate, addr, Q_DST);
4585 		gen_or(b0, b1);
4586 		return b1;
4587 
4588 	case Q_ISO:
4589 		bpf_error(cstate, "ISO host filtering not implemented");
4590 
4591 	default:
4592 		abort();
4593 	}
4594 	b0 = gen_linktype(cstate, ETHERTYPE_DN);
4595 	/* Check for pad = 1, long header case */
4596 	tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4597 	    (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
4598 	b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh,
4599 	    BPF_H, (bpf_int32)ntohs((u_short)addr));
4600 	gen_and(tmp, b1);
4601 	/* Check for pad = 0, long header case */
4602 	tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
4603 	b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4604 	gen_and(tmp, b2);
4605 	gen_or(b2, b1);
4606 	/* Check for pad = 1, short header case */
4607 	tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4608 	    (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
4609 	b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4610 	gen_and(tmp, b2);
4611 	gen_or(b2, b1);
4612 	/* Check for pad = 0, short header case */
4613 	tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
4614 	b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4615 	gen_and(tmp, b2);
4616 	gen_or(b2, b1);
4617 
4618 	/* Combine with test for cstate->linktype */
4619 	gen_and(b0, b1);
4620 	return b1;
4621 }
4622 
4623 /*
4624  * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
4625  * test the bottom-of-stack bit, and then check the version number
4626  * field in the IP header.
4627  */
4628 static struct block *
gen_mpls_linktype(compiler_state_t * cstate,int proto)4629 gen_mpls_linktype(compiler_state_t *cstate, int proto)
4630 {
4631 	struct block *b0, *b1;
4632 
4633         switch (proto) {
4634 
4635         case Q_IP:
4636                 /* match the bottom-of-stack bit */
4637                 b0 = gen_mcmp(cstate, OR_LINKPL, -2, BPF_B, 0x01, 0x01);
4638                 /* match the IPv4 version number */
4639                 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0);
4640                 gen_and(b0, b1);
4641                 return b1;
4642 
4643        case Q_IPV6:
4644                 /* match the bottom-of-stack bit */
4645                 b0 = gen_mcmp(cstate, OR_LINKPL, -2, BPF_B, 0x01, 0x01);
4646                 /* match the IPv4 version number */
4647                 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
4648                 gen_and(b0, b1);
4649                 return b1;
4650 
4651        default:
4652                 abort();
4653         }
4654 }
4655 
4656 static struct block *
gen_host(compiler_state_t * cstate,bpf_u_int32 addr,bpf_u_int32 mask,int proto,int dir,int type)4657 gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
4658     int proto, int dir, int type)
4659 {
4660 	struct block *b0, *b1;
4661 	const char *typestr;
4662 
4663 	if (type == Q_NET)
4664 		typestr = "net";
4665 	else
4666 		typestr = "host";
4667 
4668 	switch (proto) {
4669 
4670 	case Q_DEFAULT:
4671 		b0 = gen_host(cstate, addr, mask, Q_IP, dir, type);
4672 		/*
4673 		 * Only check for non-IPv4 addresses if we're not
4674 		 * checking MPLS-encapsulated packets.
4675 		 */
4676 		if (cstate->label_stack_depth == 0) {
4677 			b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type);
4678 			gen_or(b0, b1);
4679 			b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type);
4680 			gen_or(b1, b0);
4681 		}
4682 		return b0;
4683 
4684 	case Q_IP:
4685 		return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16);
4686 
4687 	case Q_RARP:
4688 		return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
4689 
4690 	case Q_ARP:
4691 		return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24);
4692 
4693 	case Q_TCP:
4694 		bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4695 
4696 	case Q_SCTP:
4697 		bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4698 
4699 	case Q_UDP:
4700 		bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4701 
4702 	case Q_ICMP:
4703 		bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4704 
4705 	case Q_IGMP:
4706 		bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4707 
4708 	case Q_IGRP:
4709 		bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4710 
4711 	case Q_PIM:
4712 		bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4713 
4714 	case Q_VRRP:
4715 		bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4716 
4717 	case Q_CARP:
4718 		bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4719 
4720 	case Q_ATALK:
4721 		bpf_error(cstate, "ATALK host filtering not implemented");
4722 
4723 	case Q_AARP:
4724 		bpf_error(cstate, "AARP host filtering not implemented");
4725 
4726 	case Q_DECNET:
4727 		return gen_dnhostop(cstate, addr, dir);
4728 
4729 	case Q_SCA:
4730 		bpf_error(cstate, "SCA host filtering not implemented");
4731 
4732 	case Q_LAT:
4733 		bpf_error(cstate, "LAT host filtering not implemented");
4734 
4735 	case Q_MOPDL:
4736 		bpf_error(cstate, "MOPDL host filtering not implemented");
4737 
4738 	case Q_MOPRC:
4739 		bpf_error(cstate, "MOPRC host filtering not implemented");
4740 
4741 	case Q_IPV6:
4742 		bpf_error(cstate, "'ip6' modifier applied to ip host");
4743 
4744 	case Q_ICMPV6:
4745 		bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4746 
4747 	case Q_AH:
4748 		bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4749 
4750 	case Q_ESP:
4751 		bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4752 
4753 	case Q_ISO:
4754 		bpf_error(cstate, "ISO host filtering not implemented");
4755 
4756 	case Q_ESIS:
4757 		bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4758 
4759 	case Q_ISIS:
4760 		bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4761 
4762 	case Q_CLNP:
4763 		bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4764 
4765 	case Q_STP:
4766 		bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4767 
4768 	case Q_IPX:
4769 		bpf_error(cstate, "IPX host filtering not implemented");
4770 
4771 	case Q_NETBEUI:
4772 		bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4773 
4774 	case Q_RADIO:
4775 		bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4776 
4777 	default:
4778 		abort();
4779 	}
4780 	/* NOTREACHED */
4781 }
4782 
4783 #ifdef INET6
4784 static struct block *
gen_host6(compiler_state_t * cstate,struct in6_addr * addr,struct in6_addr * mask,int proto,int dir,int type)4785 gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
4786     struct in6_addr *mask, int proto, int dir, int type)
4787 {
4788 	const char *typestr;
4789 
4790 	if (type == Q_NET)
4791 		typestr = "net";
4792 	else
4793 		typestr = "host";
4794 
4795 	switch (proto) {
4796 
4797 	case Q_DEFAULT:
4798 		return gen_host6(cstate, addr, mask, Q_IPV6, dir, type);
4799 
4800 	case Q_LINK:
4801 		bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr);
4802 
4803 	case Q_IP:
4804 		bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr);
4805 
4806 	case Q_RARP:
4807 		bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr);
4808 
4809 	case Q_ARP:
4810 		bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr);
4811 
4812 	case Q_SCTP:
4813 		bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4814 
4815 	case Q_TCP:
4816 		bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4817 
4818 	case Q_UDP:
4819 		bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4820 
4821 	case Q_ICMP:
4822 		bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4823 
4824 	case Q_IGMP:
4825 		bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4826 
4827 	case Q_IGRP:
4828 		bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4829 
4830 	case Q_PIM:
4831 		bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4832 
4833 	case Q_VRRP:
4834 		bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4835 
4836 	case Q_CARP:
4837 		bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4838 
4839 	case Q_ATALK:
4840 		bpf_error(cstate, "ATALK host filtering not implemented");
4841 
4842 	case Q_AARP:
4843 		bpf_error(cstate, "AARP host filtering not implemented");
4844 
4845 	case Q_DECNET:
4846 		bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr);
4847 
4848 	case Q_SCA:
4849 		bpf_error(cstate, "SCA host filtering not implemented");
4850 
4851 	case Q_LAT:
4852 		bpf_error(cstate, "LAT host filtering not implemented");
4853 
4854 	case Q_MOPDL:
4855 		bpf_error(cstate, "MOPDL host filtering not implemented");
4856 
4857 	case Q_MOPRC:
4858 		bpf_error(cstate, "MOPRC host filtering not implemented");
4859 
4860 	case Q_IPV6:
4861 		return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
4862 
4863 	case Q_ICMPV6:
4864 		bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4865 
4866 	case Q_AH:
4867 		bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4868 
4869 	case Q_ESP:
4870 		bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4871 
4872 	case Q_ISO:
4873 		bpf_error(cstate, "ISO host filtering not implemented");
4874 
4875 	case Q_ESIS:
4876 		bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4877 
4878 	case Q_ISIS:
4879 		bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4880 
4881 	case Q_CLNP:
4882 		bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4883 
4884 	case Q_STP:
4885 		bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4886 
4887 	case Q_IPX:
4888 		bpf_error(cstate, "IPX host filtering not implemented");
4889 
4890 	case Q_NETBEUI:
4891 		bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4892 
4893 	case Q_RADIO:
4894 		bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4895 
4896 	default:
4897 		abort();
4898 	}
4899 	/* NOTREACHED */
4900 }
4901 #endif
4902 
4903 #ifndef INET6
4904 static struct block *
gen_gateway(eaddr,alist,proto,dir)4905 gen_gateway(eaddr, alist, proto, dir)
4906 	const u_char *eaddr;
4907 	bpf_u_int32 **alist;
4908 	int proto;
4909 	int dir;
4910 {
4911 	struct block *b0, *b1, *tmp;
4912 
4913 	if (dir != 0)
4914 		bpf_error(cstate, "direction applied to 'gateway'");
4915 
4916 	switch (proto) {
4917 	case Q_DEFAULT:
4918 	case Q_IP:
4919 	case Q_ARP:
4920 	case Q_RARP:
4921 		switch (cstate->linktype) {
4922 		case DLT_EN10MB:
4923 		case DLT_NETANALYZER:
4924 		case DLT_NETANALYZER_TRANSPARENT:
4925 			b1 = gen_prevlinkhdr_check(cstate);
4926 			b0 = gen_ehostop(cstate, eaddr, Q_OR);
4927 			if (b1 != NULL)
4928 				gen_and(b1, b0);
4929 			break;
4930 		case DLT_FDDI:
4931 			b0 = gen_fhostop(cstate, eaddr, Q_OR);
4932 			break;
4933 		case DLT_IEEE802:
4934 			b0 = gen_thostop(cstate, eaddr, Q_OR);
4935 			break;
4936 		case DLT_IEEE802_11:
4937 		case DLT_PRISM_HEADER:
4938 		case DLT_IEEE802_11_RADIO_AVS:
4939 		case DLT_IEEE802_11_RADIO:
4940 		case DLT_PPI:
4941 			b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
4942 			break;
4943 		case DLT_SUNATM:
4944 			/*
4945 			 * This is LLC-multiplexed traffic; if it were
4946 			 * LANE, cstate->linktype would have been set to
4947 			 * DLT_EN10MB.
4948 			 */
4949 			bpf_error(cstate,
4950 			    "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
4951 			break;
4952 		case DLT_IP_OVER_FC:
4953 			b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
4954 			break;
4955 		default:
4956 			bpf_error(cstate,
4957 			    "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
4958 		}
4959 		b1 = gen_host(cstate, **alist++, 0xffffffff, proto, Q_OR, Q_HOST);
4960 		while (*alist) {
4961 			tmp = gen_host(cstate, **alist++, 0xffffffff, proto, Q_OR,
4962 			    Q_HOST);
4963 			gen_or(b1, tmp);
4964 			b1 = tmp;
4965 		}
4966 		gen_not(b1);
4967 		gen_and(b0, b1);
4968 		return b1;
4969 	}
4970 	bpf_error(cstate, "illegal modifier of 'gateway'");
4971 	/* NOTREACHED */
4972 }
4973 #endif
4974 
4975 struct block *
gen_proto_abbrev(compiler_state_t * cstate,int proto)4976 gen_proto_abbrev(compiler_state_t *cstate, int proto)
4977 {
4978 	struct block *b0;
4979 	struct block *b1;
4980 
4981 	switch (proto) {
4982 
4983 	case Q_SCTP:
4984 		b1 = gen_proto(cstate, IPPROTO_SCTP, Q_IP, Q_DEFAULT);
4985 		b0 = gen_proto(cstate, IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
4986 		gen_or(b0, b1);
4987 		break;
4988 
4989 	case Q_TCP:
4990 		b1 = gen_proto(cstate, IPPROTO_TCP, Q_IP, Q_DEFAULT);
4991 		b0 = gen_proto(cstate, IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
4992 		gen_or(b0, b1);
4993 		break;
4994 
4995 	case Q_UDP:
4996 		b1 = gen_proto(cstate, IPPROTO_UDP, Q_IP, Q_DEFAULT);
4997 		b0 = gen_proto(cstate, IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
4998 		gen_or(b0, b1);
4999 		break;
5000 
5001 	case Q_ICMP:
5002 		b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT);
5003 		break;
5004 
5005 #ifndef	IPPROTO_IGMP
5006 #define	IPPROTO_IGMP	2
5007 #endif
5008 
5009 	case Q_IGMP:
5010 		b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT);
5011 		break;
5012 
5013 #ifndef	IPPROTO_IGRP
5014 #define	IPPROTO_IGRP	9
5015 #endif
5016 	case Q_IGRP:
5017 		b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT);
5018 		break;
5019 
5020 #ifndef IPPROTO_PIM
5021 #define IPPROTO_PIM	103
5022 #endif
5023 
5024 	case Q_PIM:
5025 		b1 = gen_proto(cstate, IPPROTO_PIM, Q_IP, Q_DEFAULT);
5026 		b0 = gen_proto(cstate, IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
5027 		gen_or(b0, b1);
5028 		break;
5029 
5030 #ifndef IPPROTO_VRRP
5031 #define IPPROTO_VRRP	112
5032 #endif
5033 
5034 	case Q_VRRP:
5035 		b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT);
5036 		break;
5037 
5038 #ifndef IPPROTO_CARP
5039 #define IPPROTO_CARP	112
5040 #endif
5041 
5042 	case Q_CARP:
5043 		b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT);
5044 		break;
5045 
5046 	case Q_IP:
5047 		b1 = gen_linktype(cstate, ETHERTYPE_IP);
5048 		break;
5049 
5050 	case Q_ARP:
5051 		b1 = gen_linktype(cstate, ETHERTYPE_ARP);
5052 		break;
5053 
5054 	case Q_RARP:
5055 		b1 = gen_linktype(cstate, ETHERTYPE_REVARP);
5056 		break;
5057 
5058 	case Q_LINK:
5059 		bpf_error(cstate, "link layer applied in wrong context");
5060 
5061 	case Q_ATALK:
5062 		b1 = gen_linktype(cstate, ETHERTYPE_ATALK);
5063 		break;
5064 
5065 	case Q_AARP:
5066 		b1 = gen_linktype(cstate, ETHERTYPE_AARP);
5067 		break;
5068 
5069 	case Q_DECNET:
5070 		b1 = gen_linktype(cstate, ETHERTYPE_DN);
5071 		break;
5072 
5073 	case Q_SCA:
5074 		b1 = gen_linktype(cstate, ETHERTYPE_SCA);
5075 		break;
5076 
5077 	case Q_LAT:
5078 		b1 = gen_linktype(cstate, ETHERTYPE_LAT);
5079 		break;
5080 
5081 	case Q_MOPDL:
5082 		b1 = gen_linktype(cstate, ETHERTYPE_MOPDL);
5083 		break;
5084 
5085 	case Q_MOPRC:
5086 		b1 = gen_linktype(cstate, ETHERTYPE_MOPRC);
5087 		break;
5088 
5089 	case Q_IPV6:
5090 		b1 = gen_linktype(cstate, ETHERTYPE_IPV6);
5091 		break;
5092 
5093 #ifndef IPPROTO_ICMPV6
5094 #define IPPROTO_ICMPV6	58
5095 #endif
5096 	case Q_ICMPV6:
5097 		b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
5098 		break;
5099 
5100 #ifndef IPPROTO_AH
5101 #define IPPROTO_AH	51
5102 #endif
5103 	case Q_AH:
5104 		b1 = gen_proto(cstate, IPPROTO_AH, Q_IP, Q_DEFAULT);
5105 		b0 = gen_proto(cstate, IPPROTO_AH, Q_IPV6, Q_DEFAULT);
5106 		gen_or(b0, b1);
5107 		break;
5108 
5109 #ifndef IPPROTO_ESP
5110 #define IPPROTO_ESP	50
5111 #endif
5112 	case Q_ESP:
5113 		b1 = gen_proto(cstate, IPPROTO_ESP, Q_IP, Q_DEFAULT);
5114 		b0 = gen_proto(cstate, IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
5115 		gen_or(b0, b1);
5116 		break;
5117 
5118 	case Q_ISO:
5119 		b1 = gen_linktype(cstate, LLCSAP_ISONS);
5120 		break;
5121 
5122 	case Q_ESIS:
5123 		b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT);
5124 		break;
5125 
5126 	case Q_ISIS:
5127 		b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
5128 		break;
5129 
5130 	case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
5131 		b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5132 		b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5133 		gen_or(b0, b1);
5134 		b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5135 		gen_or(b0, b1);
5136 		b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5137 		gen_or(b0, b1);
5138 		b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5139 		gen_or(b0, b1);
5140 		break;
5141 
5142 	case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
5143 		b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5144 		b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5145 		gen_or(b0, b1);
5146 		b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5147 		gen_or(b0, b1);
5148 		b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5149 		gen_or(b0, b1);
5150 		b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5151 		gen_or(b0, b1);
5152 		break;
5153 
5154 	case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
5155 		b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5156 		b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5157 		gen_or(b0, b1);
5158 		b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
5159 		gen_or(b0, b1);
5160 		break;
5161 
5162 	case Q_ISIS_LSP:
5163 		b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5164 		b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5165 		gen_or(b0, b1);
5166 		break;
5167 
5168 	case Q_ISIS_SNP:
5169 		b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5170 		b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5171 		gen_or(b0, b1);
5172 		b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5173 		gen_or(b0, b1);
5174 		b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5175 		gen_or(b0, b1);
5176 		break;
5177 
5178 	case Q_ISIS_CSNP:
5179 		b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5180 		b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5181 		gen_or(b0, b1);
5182 		break;
5183 
5184 	case Q_ISIS_PSNP:
5185 		b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5186 		b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5187 		gen_or(b0, b1);
5188 		break;
5189 
5190 	case Q_CLNP:
5191 		b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT);
5192 		break;
5193 
5194 	case Q_STP:
5195 		b1 = gen_linktype(cstate, LLCSAP_8021D);
5196 		break;
5197 
5198 	case Q_IPX:
5199 		b1 = gen_linktype(cstate, LLCSAP_IPX);
5200 		break;
5201 
5202 	case Q_NETBEUI:
5203 		b1 = gen_linktype(cstate, LLCSAP_NETBEUI);
5204 		break;
5205 
5206 	case Q_RADIO:
5207 		bpf_error(cstate, "'radio' is not a valid protocol type");
5208 
5209 	default:
5210 		abort();
5211 	}
5212 	return b1;
5213 }
5214 
5215 static struct block *
gen_ipfrag(compiler_state_t * cstate)5216 gen_ipfrag(compiler_state_t *cstate)
5217 {
5218 	struct slist *s;
5219 	struct block *b;
5220 
5221 	/* not IPv4 frag other than the first frag */
5222 	s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H);
5223 	b = new_block(cstate, JMP(BPF_JSET));
5224 	b->s.k = 0x1fff;
5225 	b->stmts = s;
5226 	gen_not(b);
5227 
5228 	return b;
5229 }
5230 
5231 /*
5232  * Generate a comparison to a port value in the transport-layer header
5233  * at the specified offset from the beginning of that header.
5234  *
5235  * XXX - this handles a variable-length prefix preceding the link-layer
5236  * header, such as the radiotap or AVS radio prefix, but doesn't handle
5237  * variable-length link-layer headers (such as Token Ring or 802.11
5238  * headers).
5239  */
5240 static struct block *
gen_portatom(compiler_state_t * cstate,int off,bpf_int32 v)5241 gen_portatom(compiler_state_t *cstate, int off, bpf_int32 v)
5242 {
5243 	return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
5244 }
5245 
5246 static struct block *
gen_portatom6(compiler_state_t * cstate,int off,bpf_int32 v)5247 gen_portatom6(compiler_state_t *cstate, int off, bpf_int32 v)
5248 {
5249 	return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
5250 }
5251 
5252 struct block *
gen_portop(compiler_state_t * cstate,int port,int proto,int dir)5253 gen_portop(compiler_state_t *cstate, int port, int proto, int dir)
5254 {
5255 	struct block *b0, *b1, *tmp;
5256 
5257 	/* ip proto 'proto' and not a fragment other than the first fragment */
5258 	tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5259 	b0 = gen_ipfrag(cstate);
5260 	gen_and(tmp, b0);
5261 
5262 	switch (dir) {
5263 	case Q_SRC:
5264 		b1 = gen_portatom(cstate, 0, (bpf_int32)port);
5265 		break;
5266 
5267 	case Q_DST:
5268 		b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5269 		break;
5270 
5271 	case Q_OR:
5272 	case Q_DEFAULT:
5273 		tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5274 		b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5275 		gen_or(tmp, b1);
5276 		break;
5277 
5278 	case Q_AND:
5279 		tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5280 		b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5281 		gen_and(tmp, b1);
5282 		break;
5283 
5284 	default:
5285 		abort();
5286 	}
5287 	gen_and(b0, b1);
5288 
5289 	return b1;
5290 }
5291 
5292 static struct block *
gen_port(compiler_state_t * cstate,int port,int ip_proto,int dir)5293 gen_port(compiler_state_t *cstate, int port, int ip_proto, int dir)
5294 {
5295 	struct block *b0, *b1, *tmp;
5296 
5297 	/*
5298 	 * ether proto ip
5299 	 *
5300 	 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
5301 	 * not LLC encapsulation with LLCSAP_IP.
5302 	 *
5303 	 * For IEEE 802 networks - which includes 802.5 token ring
5304 	 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
5305 	 * says that SNAP encapsulation is used, not LLC encapsulation
5306 	 * with LLCSAP_IP.
5307 	 *
5308 	 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
5309 	 * RFC 2225 say that SNAP encapsulation is used, not LLC
5310 	 * encapsulation with LLCSAP_IP.
5311 	 *
5312 	 * So we always check for ETHERTYPE_IP.
5313 	 */
5314 	b0 = gen_linktype(cstate, ETHERTYPE_IP);
5315 
5316 	switch (ip_proto) {
5317 	case IPPROTO_UDP:
5318 	case IPPROTO_TCP:
5319 	case IPPROTO_SCTP:
5320 		b1 = gen_portop(cstate, port, ip_proto, dir);
5321 		break;
5322 
5323 	case PROTO_UNDEF:
5324 		tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
5325 		b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
5326 		gen_or(tmp, b1);
5327 		tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
5328 		gen_or(tmp, b1);
5329 		break;
5330 
5331 	default:
5332 		abort();
5333 	}
5334 	gen_and(b0, b1);
5335 	return b1;
5336 }
5337 
5338 struct block *
gen_portop6(compiler_state_t * cstate,int port,int proto,int dir)5339 gen_portop6(compiler_state_t *cstate, int port, int proto, int dir)
5340 {
5341 	struct block *b0, *b1, *tmp;
5342 
5343 	/* ip6 proto 'proto' */
5344 	/* XXX - catch the first fragment of a fragmented packet? */
5345 	b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5346 
5347 	switch (dir) {
5348 	case Q_SRC:
5349 		b1 = gen_portatom6(cstate, 0, (bpf_int32)port);
5350 		break;
5351 
5352 	case Q_DST:
5353 		b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5354 		break;
5355 
5356 	case Q_OR:
5357 	case Q_DEFAULT:
5358 		tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5359 		b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5360 		gen_or(tmp, b1);
5361 		break;
5362 
5363 	case Q_AND:
5364 		tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5365 		b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5366 		gen_and(tmp, b1);
5367 		break;
5368 
5369 	default:
5370 		abort();
5371 	}
5372 	gen_and(b0, b1);
5373 
5374 	return b1;
5375 }
5376 
5377 static struct block *
gen_port6(compiler_state_t * cstate,int port,int ip_proto,int dir)5378 gen_port6(compiler_state_t *cstate, int port, int ip_proto, int dir)
5379 {
5380 	struct block *b0, *b1, *tmp;
5381 
5382 	/* link proto ip6 */
5383 	b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5384 
5385 	switch (ip_proto) {
5386 	case IPPROTO_UDP:
5387 	case IPPROTO_TCP:
5388 	case IPPROTO_SCTP:
5389 		b1 = gen_portop6(cstate, port, ip_proto, dir);
5390 		break;
5391 
5392 	case PROTO_UNDEF:
5393 		tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
5394 		b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
5395 		gen_or(tmp, b1);
5396 		tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
5397 		gen_or(tmp, b1);
5398 		break;
5399 
5400 	default:
5401 		abort();
5402 	}
5403 	gen_and(b0, b1);
5404 	return b1;
5405 }
5406 
5407 /* gen_portrange code */
5408 static struct block *
gen_portrangeatom(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5409 gen_portrangeatom(compiler_state_t *cstate, int off, bpf_int32 v1,
5410     bpf_int32 v2)
5411 {
5412 	struct block *b1, *b2;
5413 
5414 	if (v1 > v2) {
5415 		/*
5416 		 * Reverse the order of the ports, so v1 is the lower one.
5417 		 */
5418 		bpf_int32 vtemp;
5419 
5420 		vtemp = v1;
5421 		v1 = v2;
5422 		v2 = vtemp;
5423 	}
5424 
5425 	b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1);
5426 	b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2);
5427 
5428 	gen_and(b1, b2);
5429 
5430 	return b2;
5431 }
5432 
5433 struct block *
gen_portrangeop(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5434 gen_portrangeop(compiler_state_t *cstate, int port1, int port2, int proto,
5435     int dir)
5436 {
5437 	struct block *b0, *b1, *tmp;
5438 
5439 	/* ip proto 'proto' and not a fragment other than the first fragment */
5440 	tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5441 	b0 = gen_ipfrag(cstate);
5442 	gen_and(tmp, b0);
5443 
5444 	switch (dir) {
5445 	case Q_SRC:
5446 		b1 = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5447 		break;
5448 
5449 	case Q_DST:
5450 		b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5451 		break;
5452 
5453 	case Q_OR:
5454 	case Q_DEFAULT:
5455 		tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5456 		b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5457 		gen_or(tmp, b1);
5458 		break;
5459 
5460 	case Q_AND:
5461 		tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5462 		b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5463 		gen_and(tmp, b1);
5464 		break;
5465 
5466 	default:
5467 		abort();
5468 	}
5469 	gen_and(b0, b1);
5470 
5471 	return b1;
5472 }
5473 
5474 static struct block *
gen_portrange(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5475 gen_portrange(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5476     int dir)
5477 {
5478 	struct block *b0, *b1, *tmp;
5479 
5480 	/* link proto ip */
5481 	b0 = gen_linktype(cstate, ETHERTYPE_IP);
5482 
5483 	switch (ip_proto) {
5484 	case IPPROTO_UDP:
5485 	case IPPROTO_TCP:
5486 	case IPPROTO_SCTP:
5487 		b1 = gen_portrangeop(cstate, port1, port2, ip_proto, dir);
5488 		break;
5489 
5490 	case PROTO_UNDEF:
5491 		tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
5492 		b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
5493 		gen_or(tmp, b1);
5494 		tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
5495 		gen_or(tmp, b1);
5496 		break;
5497 
5498 	default:
5499 		abort();
5500 	}
5501 	gen_and(b0, b1);
5502 	return b1;
5503 }
5504 
5505 static struct block *
gen_portrangeatom6(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5506 gen_portrangeatom6(compiler_state_t *cstate, int off, bpf_int32 v1,
5507     bpf_int32 v2)
5508 {
5509 	struct block *b1, *b2;
5510 
5511 	if (v1 > v2) {
5512 		/*
5513 		 * Reverse the order of the ports, so v1 is the lower one.
5514 		 */
5515 		bpf_int32 vtemp;
5516 
5517 		vtemp = v1;
5518 		v1 = v2;
5519 		v2 = vtemp;
5520 	}
5521 
5522 	b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1);
5523 	b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2);
5524 
5525 	gen_and(b1, b2);
5526 
5527 	return b2;
5528 }
5529 
5530 struct block *
gen_portrangeop6(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5531 gen_portrangeop6(compiler_state_t *cstate, int port1, int port2, int proto,
5532     int dir)
5533 {
5534 	struct block *b0, *b1, *tmp;
5535 
5536 	/* ip6 proto 'proto' */
5537 	/* XXX - catch the first fragment of a fragmented packet? */
5538 	b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5539 
5540 	switch (dir) {
5541 	case Q_SRC:
5542 		b1 = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5543 		break;
5544 
5545 	case Q_DST:
5546 		b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5547 		break;
5548 
5549 	case Q_OR:
5550 	case Q_DEFAULT:
5551 		tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5552 		b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5553 		gen_or(tmp, b1);
5554 		break;
5555 
5556 	case Q_AND:
5557 		tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5558 		b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5559 		gen_and(tmp, b1);
5560 		break;
5561 
5562 	default:
5563 		abort();
5564 	}
5565 	gen_and(b0, b1);
5566 
5567 	return b1;
5568 }
5569 
5570 static struct block *
gen_portrange6(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5571 gen_portrange6(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5572     int dir)
5573 {
5574 	struct block *b0, *b1, *tmp;
5575 
5576 	/* link proto ip6 */
5577 	b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5578 
5579 	switch (ip_proto) {
5580 	case IPPROTO_UDP:
5581 	case IPPROTO_TCP:
5582 	case IPPROTO_SCTP:
5583 		b1 = gen_portrangeop6(cstate, port1, port2, ip_proto, dir);
5584 		break;
5585 
5586 	case PROTO_UNDEF:
5587 		tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
5588 		b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
5589 		gen_or(tmp, b1);
5590 		tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
5591 		gen_or(tmp, b1);
5592 		break;
5593 
5594 	default:
5595 		abort();
5596 	}
5597 	gen_and(b0, b1);
5598 	return b1;
5599 }
5600 
5601 static int
lookup_proto(compiler_state_t * cstate,const char * name,int proto)5602 lookup_proto(compiler_state_t *cstate, const char *name, int proto)
5603 {
5604 	register int v;
5605 
5606 	switch (proto) {
5607 
5608 	case Q_DEFAULT:
5609 	case Q_IP:
5610 	case Q_IPV6:
5611 		v = pcap_nametoproto(name);
5612 		if (v == PROTO_UNDEF)
5613 			bpf_error(cstate, "unknown ip proto '%s'", name);
5614 		break;
5615 
5616 	case Q_LINK:
5617 		/* XXX should look up h/w protocol type based on cstate->linktype */
5618 		v = pcap_nametoeproto(name);
5619 		if (v == PROTO_UNDEF) {
5620 			v = pcap_nametollc(name);
5621 			if (v == PROTO_UNDEF)
5622 				bpf_error(cstate, "unknown ether proto '%s'", name);
5623 		}
5624 		break;
5625 
5626 	case Q_ISO:
5627 		if (strcmp(name, "esis") == 0)
5628 			v = ISO9542_ESIS;
5629 		else if (strcmp(name, "isis") == 0)
5630 			v = ISO10589_ISIS;
5631 		else if (strcmp(name, "clnp") == 0)
5632 			v = ISO8473_CLNP;
5633 		else
5634 			bpf_error(cstate, "unknown osi proto '%s'", name);
5635 		break;
5636 
5637 	default:
5638 		v = PROTO_UNDEF;
5639 		break;
5640 	}
5641 	return v;
5642 }
5643 
5644 #if 0
5645 struct stmt *
5646 gen_joinsp(s, n)
5647 	struct stmt **s;
5648 	int n;
5649 {
5650 	return NULL;
5651 }
5652 #endif
5653 
5654 static struct block *
gen_protochain(compiler_state_t * cstate,int v,int proto,int dir)5655 gen_protochain(compiler_state_t *cstate, int v, int proto, int dir)
5656 {
5657 #ifdef NO_PROTOCHAIN
5658 	return gen_proto(cstate, v, proto, dir);
5659 #else
5660 	struct block *b0, *b;
5661 	struct slist *s[100];
5662 	int fix2, fix3, fix4, fix5;
5663 	int ahcheck, again, end;
5664 	int i, max;
5665 	int reg2 = alloc_reg(cstate);
5666 
5667 	memset(s, 0, sizeof(s));
5668 	fix3 = fix4 = fix5 = 0;
5669 
5670 	switch (proto) {
5671 	case Q_IP:
5672 	case Q_IPV6:
5673 		break;
5674 	case Q_DEFAULT:
5675 		b0 = gen_protochain(cstate, v, Q_IP, dir);
5676 		b = gen_protochain(cstate, v, Q_IPV6, dir);
5677 		gen_or(b0, b);
5678 		return b;
5679 	default:
5680 		bpf_error(cstate, "bad protocol applied for 'protochain'");
5681 		/*NOTREACHED*/
5682 	}
5683 
5684 	/*
5685 	 * We don't handle variable-length prefixes before the link-layer
5686 	 * header, or variable-length link-layer headers, here yet.
5687 	 * We might want to add BPF instructions to do the protochain
5688 	 * work, to simplify that and, on platforms that have a BPF
5689 	 * interpreter with the new instructions, let the filtering
5690 	 * be done in the kernel.  (We already require a modified BPF
5691 	 * engine to do the protochain stuff, to support backward
5692 	 * branches, and backward branch support is unlikely to appear
5693 	 * in kernel BPF engines.)
5694 	 */
5695 	if (cstate->off_linkpl.is_variable)
5696 		bpf_error(cstate, "'protochain' not supported with variable length headers");
5697 
5698 	cstate->no_optimize = 1; /*this code is not compatible with optimzer yet */
5699 
5700 	/*
5701 	 * s[0] is a dummy entry to protect other BPF insn from damage
5702 	 * by s[fix] = foo with uninitialized variable "fix".  It is somewhat
5703 	 * hard to find interdependency made by jump table fixup.
5704 	 */
5705 	i = 0;
5706 	s[i] = new_stmt(cstate, 0);	/*dummy*/
5707 	i++;
5708 
5709 	switch (proto) {
5710 	case Q_IP:
5711 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
5712 
5713 		/* A = ip->ip_p */
5714 		s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5715 		s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9;
5716 		i++;
5717 		/* X = ip->ip_hl << 2 */
5718 		s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
5719 		s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5720 		i++;
5721 		break;
5722 
5723 	case Q_IPV6:
5724 		b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5725 
5726 		/* A = ip6->ip_nxt */
5727 		s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5728 		s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6;
5729 		i++;
5730 		/* X = sizeof(struct ip6_hdr) */
5731 		s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM);
5732 		s[i]->s.k = 40;
5733 		i++;
5734 		break;
5735 
5736 	default:
5737 		bpf_error(cstate, "unsupported proto to gen_protochain");
5738 		/*NOTREACHED*/
5739 	}
5740 
5741 	/* again: if (A == v) goto end; else fall through; */
5742 	again = i;
5743 	s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5744 	s[i]->s.k = v;
5745 	s[i]->s.jt = NULL;		/*later*/
5746 	s[i]->s.jf = NULL;		/*update in next stmt*/
5747 	fix5 = i;
5748 	i++;
5749 
5750 #ifndef IPPROTO_NONE
5751 #define IPPROTO_NONE	59
5752 #endif
5753 	/* if (A == IPPROTO_NONE) goto end */
5754 	s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5755 	s[i]->s.jt = NULL;	/*later*/
5756 	s[i]->s.jf = NULL;	/*update in next stmt*/
5757 	s[i]->s.k = IPPROTO_NONE;
5758 	s[fix5]->s.jf = s[i];
5759 	fix2 = i;
5760 	i++;
5761 
5762 	if (proto == Q_IPV6) {
5763 		int v6start, v6end, v6advance, j;
5764 
5765 		v6start = i;
5766 		/* if (A == IPPROTO_HOPOPTS) goto v6advance */
5767 		s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5768 		s[i]->s.jt = NULL;	/*later*/
5769 		s[i]->s.jf = NULL;	/*update in next stmt*/
5770 		s[i]->s.k = IPPROTO_HOPOPTS;
5771 		s[fix2]->s.jf = s[i];
5772 		i++;
5773 		/* if (A == IPPROTO_DSTOPTS) goto v6advance */
5774 		s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5775 		s[i]->s.jt = NULL;	/*later*/
5776 		s[i]->s.jf = NULL;	/*update in next stmt*/
5777 		s[i]->s.k = IPPROTO_DSTOPTS;
5778 		i++;
5779 		/* if (A == IPPROTO_ROUTING) goto v6advance */
5780 		s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5781 		s[i]->s.jt = NULL;	/*later*/
5782 		s[i]->s.jf = NULL;	/*update in next stmt*/
5783 		s[i]->s.k = IPPROTO_ROUTING;
5784 		i++;
5785 		/* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
5786 		s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5787 		s[i]->s.jt = NULL;	/*later*/
5788 		s[i]->s.jf = NULL;	/*later*/
5789 		s[i]->s.k = IPPROTO_FRAGMENT;
5790 		fix3 = i;
5791 		v6end = i;
5792 		i++;
5793 
5794 		/* v6advance: */
5795 		v6advance = i;
5796 
5797 		/*
5798 		 * in short,
5799 		 * A = P[X + packet head];
5800 		 * X = X + (P[X + packet head + 1] + 1) * 8;
5801 		 */
5802 		/* A = P[X + packet head] */
5803 		s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5804 		s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5805 		i++;
5806 		/* MEM[reg2] = A */
5807 		s[i] = new_stmt(cstate, BPF_ST);
5808 		s[i]->s.k = reg2;
5809 		i++;
5810 		/* A = P[X + packet head + 1]; */
5811 		s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5812 		s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1;
5813 		i++;
5814 		/* A += 1 */
5815 		s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5816 		s[i]->s.k = 1;
5817 		i++;
5818 		/* A *= 8 */
5819 		s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
5820 		s[i]->s.k = 8;
5821 		i++;
5822 		/* A += X */
5823 		s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
5824 		s[i]->s.k = 0;
5825 		i++;
5826 		/* X = A; */
5827 		s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
5828 		i++;
5829 		/* A = MEM[reg2] */
5830 		s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
5831 		s[i]->s.k = reg2;
5832 		i++;
5833 
5834 		/* goto again; (must use BPF_JA for backward jump) */
5835 		s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
5836 		s[i]->s.k = again - i - 1;
5837 		s[i - 1]->s.jf = s[i];
5838 		i++;
5839 
5840 		/* fixup */
5841 		for (j = v6start; j <= v6end; j++)
5842 			s[j]->s.jt = s[v6advance];
5843 	} else {
5844 		/* nop */
5845 		s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5846 		s[i]->s.k = 0;
5847 		s[fix2]->s.jf = s[i];
5848 		i++;
5849 	}
5850 
5851 	/* ahcheck: */
5852 	ahcheck = i;
5853 	/* if (A == IPPROTO_AH) then fall through; else goto end; */
5854 	s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5855 	s[i]->s.jt = NULL;	/*later*/
5856 	s[i]->s.jf = NULL;	/*later*/
5857 	s[i]->s.k = IPPROTO_AH;
5858 	if (fix3)
5859 		s[fix3]->s.jf = s[ahcheck];
5860 	fix4 = i;
5861 	i++;
5862 
5863 	/*
5864 	 * in short,
5865 	 * A = P[X];
5866 	 * X = X + (P[X + 1] + 2) * 4;
5867 	 */
5868 	/* A = X */
5869 	s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
5870 	i++;
5871 	/* A = P[X + packet head]; */
5872 	s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5873 	s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5874 	i++;
5875 	/* MEM[reg2] = A */
5876 	s[i] = new_stmt(cstate, BPF_ST);
5877 	s[i]->s.k = reg2;
5878 	i++;
5879 	/* A = X */
5880 	s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
5881 	i++;
5882 	/* A += 1 */
5883 	s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5884 	s[i]->s.k = 1;
5885 	i++;
5886 	/* X = A */
5887 	s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
5888 	i++;
5889 	/* A = P[X + packet head] */
5890 	s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5891 	s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5892 	i++;
5893 	/* A += 2 */
5894 	s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5895 	s[i]->s.k = 2;
5896 	i++;
5897 	/* A *= 4 */
5898 	s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
5899 	s[i]->s.k = 4;
5900 	i++;
5901 	/* X = A; */
5902 	s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
5903 	i++;
5904 	/* A = MEM[reg2] */
5905 	s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
5906 	s[i]->s.k = reg2;
5907 	i++;
5908 
5909 	/* goto again; (must use BPF_JA for backward jump) */
5910 	s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
5911 	s[i]->s.k = again - i - 1;
5912 	i++;
5913 
5914 	/* end: nop */
5915 	end = i;
5916 	s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5917 	s[i]->s.k = 0;
5918 	s[fix2]->s.jt = s[end];
5919 	s[fix4]->s.jf = s[end];
5920 	s[fix5]->s.jt = s[end];
5921 	i++;
5922 
5923 	/*
5924 	 * make slist chain
5925 	 */
5926 	max = i;
5927 	for (i = 0; i < max - 1; i++)
5928 		s[i]->next = s[i + 1];
5929 	s[max - 1]->next = NULL;
5930 
5931 	/*
5932 	 * emit final check
5933 	 */
5934 	b = new_block(cstate, JMP(BPF_JEQ));
5935 	b->stmts = s[1];	/*remember, s[0] is dummy*/
5936 	b->s.k = v;
5937 
5938 	free_reg(cstate, reg2);
5939 
5940 	gen_and(b0, b);
5941 	return b;
5942 #endif
5943 }
5944 
5945 static struct block *
gen_check_802_11_data_frame(compiler_state_t * cstate)5946 gen_check_802_11_data_frame(compiler_state_t *cstate)
5947 {
5948 	struct slist *s;
5949 	struct block *b0, *b1;
5950 
5951 	/*
5952 	 * A data frame has the 0x08 bit (b3) in the frame control field set
5953 	 * and the 0x04 bit (b2) clear.
5954 	 */
5955 	s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
5956 	b0 = new_block(cstate, JMP(BPF_JSET));
5957 	b0->s.k = 0x08;
5958 	b0->stmts = s;
5959 
5960 	s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
5961 	b1 = new_block(cstate, JMP(BPF_JSET));
5962 	b1->s.k = 0x04;
5963 	b1->stmts = s;
5964 	gen_not(b1);
5965 
5966 	gen_and(b1, b0);
5967 
5968 	return b0;
5969 }
5970 
5971 /*
5972  * Generate code that checks whether the packet is a packet for protocol
5973  * <proto> and whether the type field in that protocol's header has
5974  * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
5975  * IP packet and checks the protocol number in the IP header against <v>.
5976  *
5977  * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
5978  * against Q_IP and Q_IPV6.
5979  */
5980 static struct block *
gen_proto(compiler_state_t * cstate,int v,int proto,int dir)5981 gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
5982 {
5983 	struct block *b0, *b1;
5984 #ifndef CHASE_CHAIN
5985 	struct block *b2;
5986 #endif
5987 
5988 	if (dir != Q_DEFAULT)
5989 		bpf_error(cstate, "direction applied to 'proto'");
5990 
5991 	switch (proto) {
5992 	case Q_DEFAULT:
5993 		b0 = gen_proto(cstate, v, Q_IP, dir);
5994 		b1 = gen_proto(cstate, v, Q_IPV6, dir);
5995 		gen_or(b0, b1);
5996 		return b1;
5997 
5998 	case Q_IP:
5999 		/*
6000 		 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
6001 		 * not LLC encapsulation with LLCSAP_IP.
6002 		 *
6003 		 * For IEEE 802 networks - which includes 802.5 token ring
6004 		 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
6005 		 * says that SNAP encapsulation is used, not LLC encapsulation
6006 		 * with LLCSAP_IP.
6007 		 *
6008 		 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
6009 		 * RFC 2225 say that SNAP encapsulation is used, not LLC
6010 		 * encapsulation with LLCSAP_IP.
6011 		 *
6012 		 * So we always check for ETHERTYPE_IP.
6013 		 */
6014 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
6015 #ifndef CHASE_CHAIN
6016 		b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)v);
6017 #else
6018 		b1 = gen_protochain(cstate, v, Q_IP);
6019 #endif
6020 		gen_and(b0, b1);
6021 		return b1;
6022 
6023 	case Q_ISO:
6024 		switch (cstate->linktype) {
6025 
6026 		case DLT_FRELAY:
6027 			/*
6028 			 * Frame Relay packets typically have an OSI
6029 			 * NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)"
6030 			 * generates code to check for all the OSI
6031 			 * NLPIDs, so calling it and then adding a check
6032 			 * for the particular NLPID for which we're
6033 			 * looking is bogus, as we can just check for
6034 			 * the NLPID.
6035 			 *
6036 			 * What we check for is the NLPID and a frame
6037 			 * control field value of UI, i.e. 0x03 followed
6038 			 * by the NLPID.
6039 			 *
6040 			 * XXX - assumes a 2-byte Frame Relay header with
6041 			 * DLCI and flags.  What if the address is longer?
6042 			 *
6043 			 * XXX - what about SNAP-encapsulated frames?
6044 			 */
6045 			return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v);
6046 			/*NOTREACHED*/
6047 			break;
6048 
6049 		case DLT_C_HDLC:
6050 			/*
6051 			 * Cisco uses an Ethertype lookalike - for OSI,
6052 			 * it's 0xfefe.
6053 			 */
6054 			b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
6055 			/* OSI in C-HDLC is stuffed with a fudge byte */
6056 			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
6057 			gen_and(b0, b1);
6058 			return b1;
6059 
6060 		default:
6061 			b0 = gen_linktype(cstate, LLCSAP_ISONS);
6062 			b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
6063 			gen_and(b0, b1);
6064 			return b1;
6065 		}
6066 
6067 	case Q_ISIS:
6068 		b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
6069 		/*
6070 		 * 4 is the offset of the PDU type relative to the IS-IS
6071 		 * header.
6072 		 */
6073 		b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
6074 		gen_and(b0, b1);
6075 		return b1;
6076 
6077 	case Q_ARP:
6078 		bpf_error(cstate, "arp does not encapsulate another protocol");
6079 		/* NOTREACHED */
6080 
6081 	case Q_RARP:
6082 		bpf_error(cstate, "rarp does not encapsulate another protocol");
6083 		/* NOTREACHED */
6084 
6085 	case Q_ATALK:
6086 		bpf_error(cstate, "atalk encapsulation is not specifiable");
6087 		/* NOTREACHED */
6088 
6089 	case Q_DECNET:
6090 		bpf_error(cstate, "decnet encapsulation is not specifiable");
6091 		/* NOTREACHED */
6092 
6093 	case Q_SCA:
6094 		bpf_error(cstate, "sca does not encapsulate another protocol");
6095 		/* NOTREACHED */
6096 
6097 	case Q_LAT:
6098 		bpf_error(cstate, "lat does not encapsulate another protocol");
6099 		/* NOTREACHED */
6100 
6101 	case Q_MOPRC:
6102 		bpf_error(cstate, "moprc does not encapsulate another protocol");
6103 		/* NOTREACHED */
6104 
6105 	case Q_MOPDL:
6106 		bpf_error(cstate, "mopdl does not encapsulate another protocol");
6107 		/* NOTREACHED */
6108 
6109 	case Q_LINK:
6110 		return gen_linktype(cstate, v);
6111 
6112 	case Q_UDP:
6113 		bpf_error(cstate, "'udp proto' is bogus");
6114 		/* NOTREACHED */
6115 
6116 	case Q_TCP:
6117 		bpf_error(cstate, "'tcp proto' is bogus");
6118 		/* NOTREACHED */
6119 
6120 	case Q_SCTP:
6121 		bpf_error(cstate, "'sctp proto' is bogus");
6122 		/* NOTREACHED */
6123 
6124 	case Q_ICMP:
6125 		bpf_error(cstate, "'icmp proto' is bogus");
6126 		/* NOTREACHED */
6127 
6128 	case Q_IGMP:
6129 		bpf_error(cstate, "'igmp proto' is bogus");
6130 		/* NOTREACHED */
6131 
6132 	case Q_IGRP:
6133 		bpf_error(cstate, "'igrp proto' is bogus");
6134 		/* NOTREACHED */
6135 
6136 	case Q_PIM:
6137 		bpf_error(cstate, "'pim proto' is bogus");
6138 		/* NOTREACHED */
6139 
6140 	case Q_VRRP:
6141 		bpf_error(cstate, "'vrrp proto' is bogus");
6142 		/* NOTREACHED */
6143 
6144 	case Q_CARP:
6145 		bpf_error(cstate, "'carp proto' is bogus");
6146 		/* NOTREACHED */
6147 
6148 	case Q_IPV6:
6149 		b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
6150 #ifndef CHASE_CHAIN
6151 		/*
6152 		 * Also check for a fragment header before the final
6153 		 * header.
6154 		 */
6155 		b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
6156 		b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, (bpf_int32)v);
6157 		gen_and(b2, b1);
6158 		b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)v);
6159 		gen_or(b2, b1);
6160 #else
6161 		b1 = gen_protochain(cstate, v, Q_IPV6);
6162 #endif
6163 		gen_and(b0, b1);
6164 		return b1;
6165 
6166 	case Q_ICMPV6:
6167 		bpf_error(cstate, "'icmp6 proto' is bogus");
6168 
6169 	case Q_AH:
6170 		bpf_error(cstate, "'ah proto' is bogus");
6171 
6172 	case Q_ESP:
6173 		bpf_error(cstate, "'ah proto' is bogus");
6174 
6175 	case Q_STP:
6176 		bpf_error(cstate, "'stp proto' is bogus");
6177 
6178 	case Q_IPX:
6179 		bpf_error(cstate, "'ipx proto' is bogus");
6180 
6181 	case Q_NETBEUI:
6182 		bpf_error(cstate, "'netbeui proto' is bogus");
6183 
6184 	case Q_RADIO:
6185 		bpf_error(cstate, "'radio proto' is bogus");
6186 
6187 	default:
6188 		abort();
6189 		/* NOTREACHED */
6190 	}
6191 	/* NOTREACHED */
6192 }
6193 
6194 struct block *
gen_scode(compiler_state_t * cstate,const char * name,struct qual q)6195 gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
6196 {
6197 	int proto = q.proto;
6198 	int dir = q.dir;
6199 	int tproto;
6200 	u_char *eaddr;
6201 	bpf_u_int32 mask, addr;
6202 #ifndef INET6
6203 	bpf_u_int32 **alist;
6204 #else
6205 	int tproto6;
6206 	struct sockaddr_in *sin4;
6207 	struct sockaddr_in6 *sin6;
6208 	struct addrinfo *res, *res0;
6209 	struct in6_addr mask128;
6210 #endif /*INET6*/
6211 	struct block *b, *tmp;
6212 	int port, real_proto;
6213 	int port1, port2;
6214 
6215 	switch (q.addr) {
6216 
6217 	case Q_NET:
6218 		addr = pcap_nametonetaddr(name);
6219 		if (addr == 0)
6220 			bpf_error(cstate, "unknown network '%s'", name);
6221 		/* Left justify network addr and calculate its network mask */
6222 		mask = 0xffffffff;
6223 		while (addr && (addr & 0xff000000) == 0) {
6224 			addr <<= 8;
6225 			mask <<= 8;
6226 		}
6227 		return gen_host(cstate, addr, mask, proto, dir, q.addr);
6228 
6229 	case Q_DEFAULT:
6230 	case Q_HOST:
6231 		if (proto == Q_LINK) {
6232 			switch (cstate->linktype) {
6233 
6234 			case DLT_EN10MB:
6235 			case DLT_NETANALYZER:
6236 			case DLT_NETANALYZER_TRANSPARENT:
6237 				eaddr = pcap_ether_hostton(name);
6238 				if (eaddr == NULL)
6239 					bpf_error(cstate,
6240 					    "unknown ether host '%s'", name);
6241 				tmp = gen_prevlinkhdr_check(cstate);
6242 				b = gen_ehostop(cstate, eaddr, dir);
6243 				if (tmp != NULL)
6244 					gen_and(tmp, b);
6245 				free(eaddr);
6246 				return b;
6247 
6248 			case DLT_FDDI:
6249 				eaddr = pcap_ether_hostton(name);
6250 				if (eaddr == NULL)
6251 					bpf_error(cstate,
6252 					    "unknown FDDI host '%s'", name);
6253 				b = gen_fhostop(cstate, eaddr, dir);
6254 				free(eaddr);
6255 				return b;
6256 
6257 			case DLT_IEEE802:
6258 				eaddr = pcap_ether_hostton(name);
6259 				if (eaddr == NULL)
6260 					bpf_error(cstate,
6261 					    "unknown token ring host '%s'", name);
6262 				b = gen_thostop(cstate, eaddr, dir);
6263 				free(eaddr);
6264 				return b;
6265 
6266 			case DLT_IEEE802_11:
6267 			case DLT_PRISM_HEADER:
6268 			case DLT_IEEE802_11_RADIO_AVS:
6269 			case DLT_IEEE802_11_RADIO:
6270 			case DLT_PPI:
6271 				eaddr = pcap_ether_hostton(name);
6272 				if (eaddr == NULL)
6273 					bpf_error(cstate,
6274 					    "unknown 802.11 host '%s'", name);
6275 				b = gen_wlanhostop(cstate, eaddr, dir);
6276 				free(eaddr);
6277 				return b;
6278 
6279 			case DLT_IP_OVER_FC:
6280 				eaddr = pcap_ether_hostton(name);
6281 				if (eaddr == NULL)
6282 					bpf_error(cstate,
6283 					    "unknown Fibre Channel host '%s'", name);
6284 				b = gen_ipfchostop(cstate, eaddr, dir);
6285 				free(eaddr);
6286 				return b;
6287 			}
6288 
6289 			bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
6290 		} else if (proto == Q_DECNET) {
6291 			unsigned short dn_addr;
6292 
6293 			if (!__pcap_nametodnaddr(name, &dn_addr)) {
6294 #ifdef	DECNETLIB
6295 				bpf_error(cstate, "unknown decnet host name '%s'\n", name);
6296 #else
6297 				bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n",
6298 					name);
6299 #endif
6300 			}
6301 			/*
6302 			 * I don't think DECNET hosts can be multihomed, so
6303 			 * there is no need to build up a list of addresses
6304 			 */
6305 			return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr));
6306 		} else {
6307 #ifndef INET6
6308 			alist = pcap_nametoaddr(name);
6309 			if (alist == NULL || *alist == NULL)
6310 				bpf_error(cstate, "unknown host '%s'", name);
6311 			tproto = proto;
6312 			if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
6313 			    tproto == Q_DEFAULT)
6314 				tproto = Q_IP;
6315 			b = gen_host(cstate, **alist++, 0xffffffff, tproto, dir, q.addr);
6316 			while (*alist) {
6317 				tmp = gen_host(cstate, **alist++, 0xffffffff,
6318 					       tproto, dir, q.addr);
6319 				gen_or(b, tmp);
6320 				b = tmp;
6321 			}
6322 			return b;
6323 #else
6324 			memset(&mask128, 0xff, sizeof(mask128));
6325 			res0 = res = pcap_nametoaddrinfo(name);
6326 			if (res == NULL)
6327 				bpf_error(cstate, "unknown host '%s'", name);
6328 			cstate->ai = res;
6329 			b = tmp = NULL;
6330 			tproto = tproto6 = proto;
6331 			if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
6332 			    tproto == Q_DEFAULT) {
6333 				tproto = Q_IP;
6334 				tproto6 = Q_IPV6;
6335 			}
6336 			for (res = res0; res; res = res->ai_next) {
6337 				switch (res->ai_family) {
6338 				case AF_INET:
6339 					if (tproto == Q_IPV6)
6340 						continue;
6341 
6342 					sin4 = (struct sockaddr_in *)
6343 						res->ai_addr;
6344 					tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
6345 						0xffffffff, tproto, dir, q.addr);
6346 					break;
6347 				case AF_INET6:
6348 					if (tproto6 == Q_IP)
6349 						continue;
6350 
6351 					sin6 = (struct sockaddr_in6 *)
6352 						res->ai_addr;
6353 					tmp = gen_host6(cstate, &sin6->sin6_addr,
6354 						&mask128, tproto6, dir, q.addr);
6355 					break;
6356 				default:
6357 					continue;
6358 				}
6359 				if (b)
6360 					gen_or(b, tmp);
6361 				b = tmp;
6362 			}
6363 			cstate->ai = NULL;
6364 			freeaddrinfo(res0);
6365 			if (b == NULL) {
6366 				bpf_error(cstate, "unknown host '%s'%s", name,
6367 				    (proto == Q_DEFAULT)
6368 					? ""
6369 					: " for specified address family");
6370 			}
6371 			return b;
6372 #endif /*INET6*/
6373 		}
6374 
6375 	case Q_PORT:
6376 		if (proto != Q_DEFAULT &&
6377 		    proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6378 			bpf_error(cstate, "illegal qualifier of 'port'");
6379 		if (pcap_nametoport(name, &port, &real_proto) == 0)
6380 			bpf_error(cstate, "unknown port '%s'", name);
6381 		if (proto == Q_UDP) {
6382 			if (real_proto == IPPROTO_TCP)
6383 				bpf_error(cstate, "port '%s' is tcp", name);
6384 			else if (real_proto == IPPROTO_SCTP)
6385 				bpf_error(cstate, "port '%s' is sctp", name);
6386 			else
6387 				/* override PROTO_UNDEF */
6388 				real_proto = IPPROTO_UDP;
6389 		}
6390 		if (proto == Q_TCP) {
6391 			if (real_proto == IPPROTO_UDP)
6392 				bpf_error(cstate, "port '%s' is udp", name);
6393 
6394 			else if (real_proto == IPPROTO_SCTP)
6395 				bpf_error(cstate, "port '%s' is sctp", name);
6396 			else
6397 				/* override PROTO_UNDEF */
6398 				real_proto = IPPROTO_TCP;
6399 		}
6400 		if (proto == Q_SCTP) {
6401 			if (real_proto == IPPROTO_UDP)
6402 				bpf_error(cstate, "port '%s' is udp", name);
6403 
6404 			else if (real_proto == IPPROTO_TCP)
6405 				bpf_error(cstate, "port '%s' is tcp", name);
6406 			else
6407 				/* override PROTO_UNDEF */
6408 				real_proto = IPPROTO_SCTP;
6409 		}
6410 		if (port < 0)
6411 			bpf_error(cstate, "illegal port number %d < 0", port);
6412 		if (port > 65535)
6413 			bpf_error(cstate, "illegal port number %d > 65535", port);
6414 		b = gen_port(cstate, port, real_proto, dir);
6415 		gen_or(gen_port6(cstate, port, real_proto, dir), b);
6416 		return b;
6417 
6418 	case Q_PORTRANGE:
6419 		if (proto != Q_DEFAULT &&
6420 		    proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6421 			bpf_error(cstate, "illegal qualifier of 'portrange'");
6422 		if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
6423 			bpf_error(cstate, "unknown port in range '%s'", name);
6424 		if (proto == Q_UDP) {
6425 			if (real_proto == IPPROTO_TCP)
6426 				bpf_error(cstate, "port in range '%s' is tcp", name);
6427 			else if (real_proto == IPPROTO_SCTP)
6428 				bpf_error(cstate, "port in range '%s' is sctp", name);
6429 			else
6430 				/* override PROTO_UNDEF */
6431 				real_proto = IPPROTO_UDP;
6432 		}
6433 		if (proto == Q_TCP) {
6434 			if (real_proto == IPPROTO_UDP)
6435 				bpf_error(cstate, "port in range '%s' is udp", name);
6436 			else if (real_proto == IPPROTO_SCTP)
6437 				bpf_error(cstate, "port in range '%s' is sctp", name);
6438 			else
6439 				/* override PROTO_UNDEF */
6440 				real_proto = IPPROTO_TCP;
6441 		}
6442 		if (proto == Q_SCTP) {
6443 			if (real_proto == IPPROTO_UDP)
6444 				bpf_error(cstate, "port in range '%s' is udp", name);
6445 			else if (real_proto == IPPROTO_TCP)
6446 				bpf_error(cstate, "port in range '%s' is tcp", name);
6447 			else
6448 				/* override PROTO_UNDEF */
6449 				real_proto = IPPROTO_SCTP;
6450 		}
6451 		if (port1 < 0)
6452 			bpf_error(cstate, "illegal port number %d < 0", port1);
6453 		if (port1 > 65535)
6454 			bpf_error(cstate, "illegal port number %d > 65535", port1);
6455 		if (port2 < 0)
6456 			bpf_error(cstate, "illegal port number %d < 0", port2);
6457 		if (port2 > 65535)
6458 			bpf_error(cstate, "illegal port number %d > 65535", port2);
6459 
6460 		b = gen_portrange(cstate, port1, port2, real_proto, dir);
6461 		gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
6462 		return b;
6463 
6464 	case Q_GATEWAY:
6465 #ifndef INET6
6466 		eaddr = pcap_ether_hostton(name);
6467 		if (eaddr == NULL)
6468 			bpf_error(cstate, "unknown ether host: %s", name);
6469 
6470 		alist = pcap_nametoaddr(name);
6471 		if (alist == NULL || *alist == NULL)
6472 			bpf_error(cstate, "unknown host '%s'", name);
6473 		b = gen_gateway(eaddr, alist, proto, dir);
6474 		free(eaddr);
6475 		return b;
6476 #else
6477 		bpf_error(cstate, "'gateway' not supported in this configuration");
6478 #endif /*INET6*/
6479 
6480 	case Q_PROTO:
6481 		real_proto = lookup_proto(cstate, name, proto);
6482 		if (real_proto >= 0)
6483 			return gen_proto(cstate, real_proto, proto, dir);
6484 		else
6485 			bpf_error(cstate, "unknown protocol: %s", name);
6486 
6487 	case Q_PROTOCHAIN:
6488 		real_proto = lookup_proto(cstate, name, proto);
6489 		if (real_proto >= 0)
6490 			return gen_protochain(cstate, real_proto, proto, dir);
6491 		else
6492 			bpf_error(cstate, "unknown protocol: %s", name);
6493 
6494 	case Q_UNDEF:
6495 		syntax(cstate);
6496 		/* NOTREACHED */
6497 	}
6498 	abort();
6499 	/* NOTREACHED */
6500 }
6501 
6502 struct block *
gen_mcode(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)6503 gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
6504     unsigned int masklen, struct qual q)
6505 {
6506 	register int nlen, mlen;
6507 	bpf_u_int32 n, m;
6508 
6509 	nlen = __pcap_atoin(s1, &n);
6510 	/* Promote short ipaddr */
6511 	n <<= 32 - nlen;
6512 
6513 	if (s2 != NULL) {
6514 		mlen = __pcap_atoin(s2, &m);
6515 		/* Promote short ipaddr */
6516 		m <<= 32 - mlen;
6517 		if ((n & ~m) != 0)
6518 			bpf_error(cstate, "non-network bits set in \"%s mask %s\"",
6519 			    s1, s2);
6520 	} else {
6521 		/* Convert mask len to mask */
6522 		if (masklen > 32)
6523 			bpf_error(cstate, "mask length must be <= 32");
6524 		if (masklen == 0) {
6525 			/*
6526 			 * X << 32 is not guaranteed by C to be 0; it's
6527 			 * undefined.
6528 			 */
6529 			m = 0;
6530 		} else
6531 			m = 0xffffffff << (32 - masklen);
6532 		if ((n & ~m) != 0)
6533 			bpf_error(cstate, "non-network bits set in \"%s/%d\"",
6534 			    s1, masklen);
6535 	}
6536 
6537 	switch (q.addr) {
6538 
6539 	case Q_NET:
6540 		return gen_host(cstate, n, m, q.proto, q.dir, q.addr);
6541 
6542 	default:
6543 		bpf_error(cstate, "Mask syntax for networks only");
6544 		/* NOTREACHED */
6545 	}
6546 	/* NOTREACHED */
6547 	return NULL;
6548 }
6549 
6550 struct block *
gen_ncode(compiler_state_t * cstate,const char * s,bpf_u_int32 v,struct qual q)6551 gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
6552 {
6553 	bpf_u_int32 mask;
6554 	int proto = q.proto;
6555 	int dir = q.dir;
6556 	register int vlen;
6557 
6558 	if (s == NULL)
6559 		vlen = 32;
6560 	else if (q.proto == Q_DECNET) {
6561 		vlen = __pcap_atodn(s, &v);
6562 		if (vlen == 0)
6563 			bpf_error(cstate, "malformed decnet address '%s'", s);
6564 	} else
6565 		vlen = __pcap_atoin(s, &v);
6566 
6567 	switch (q.addr) {
6568 
6569 	case Q_DEFAULT:
6570 	case Q_HOST:
6571 	case Q_NET:
6572 		if (proto == Q_DECNET)
6573 			return gen_host(cstate, v, 0, proto, dir, q.addr);
6574 		else if (proto == Q_LINK) {
6575 			bpf_error(cstate, "illegal link layer address");
6576 		} else {
6577 			mask = 0xffffffff;
6578 			if (s == NULL && q.addr == Q_NET) {
6579 				/* Promote short net number */
6580 				while (v && (v & 0xff000000) == 0) {
6581 					v <<= 8;
6582 					mask <<= 8;
6583 				}
6584 			} else {
6585 				/* Promote short ipaddr */
6586 				v <<= 32 - vlen;
6587 				mask <<= 32 - vlen ;
6588 			}
6589 			return gen_host(cstate, v, mask, proto, dir, q.addr);
6590 		}
6591 
6592 	case Q_PORT:
6593 		if (proto == Q_UDP)
6594 			proto = IPPROTO_UDP;
6595 		else if (proto == Q_TCP)
6596 			proto = IPPROTO_TCP;
6597 		else if (proto == Q_SCTP)
6598 			proto = IPPROTO_SCTP;
6599 		else if (proto == Q_DEFAULT)
6600 			proto = PROTO_UNDEF;
6601 		else
6602 			bpf_error(cstate, "illegal qualifier of 'port'");
6603 
6604 		if (v > 65535)
6605 			bpf_error(cstate, "illegal port number %u > 65535", v);
6606 
6607 	    {
6608 		struct block *b;
6609 		b = gen_port(cstate, (int)v, proto, dir);
6610 		gen_or(gen_port6(cstate, (int)v, proto, dir), b);
6611 		return b;
6612 	    }
6613 
6614 	case Q_PORTRANGE:
6615 		if (proto == Q_UDP)
6616 			proto = IPPROTO_UDP;
6617 		else if (proto == Q_TCP)
6618 			proto = IPPROTO_TCP;
6619 		else if (proto == Q_SCTP)
6620 			proto = IPPROTO_SCTP;
6621 		else if (proto == Q_DEFAULT)
6622 			proto = PROTO_UNDEF;
6623 		else
6624 			bpf_error(cstate, "illegal qualifier of 'portrange'");
6625 
6626 		if (v > 65535)
6627 			bpf_error(cstate, "illegal port number %u > 65535", v);
6628 
6629 	    {
6630 		struct block *b;
6631 		b = gen_portrange(cstate, (int)v, (int)v, proto, dir);
6632 		gen_or(gen_portrange6(cstate, (int)v, (int)v, proto, dir), b);
6633 		return b;
6634 	    }
6635 
6636 	case Q_GATEWAY:
6637 		bpf_error(cstate, "'gateway' requires a name");
6638 		/* NOTREACHED */
6639 
6640 	case Q_PROTO:
6641 		return gen_proto(cstate, (int)v, proto, dir);
6642 
6643 	case Q_PROTOCHAIN:
6644 		return gen_protochain(cstate, (int)v, proto, dir);
6645 
6646 	case Q_UNDEF:
6647 		syntax(cstate);
6648 		/* NOTREACHED */
6649 
6650 	default:
6651 		abort();
6652 		/* NOTREACHED */
6653 	}
6654 	/* NOTREACHED */
6655 }
6656 
6657 #ifdef INET6
6658 struct block *
gen_mcode6(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)6659 gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
6660     unsigned int masklen, struct qual q)
6661 {
6662 	struct addrinfo *res;
6663 	struct in6_addr *addr;
6664 	struct in6_addr mask;
6665 	struct block *b;
6666 	u_int32_t *a, *m;
6667 
6668 	if (s2)
6669 		bpf_error(cstate, "no mask %s supported", s2);
6670 
6671 	res = pcap_nametoaddrinfo(s1);
6672 	if (!res)
6673 		bpf_error(cstate, "invalid ip6 address %s", s1);
6674 	cstate->ai = res;
6675 	if (res->ai_next)
6676 		bpf_error(cstate, "%s resolved to multiple address", s1);
6677 	addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
6678 
6679 	if (sizeof(mask) * 8 < masklen)
6680 		bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
6681 	memset(&mask, 0, sizeof(mask));
6682 	memset(&mask, 0xff, masklen / 8);
6683 	if (masklen % 8) {
6684 		mask.s6_addr[masklen / 8] =
6685 			(0xff << (8 - masklen % 8)) & 0xff;
6686 	}
6687 
6688 	a = (u_int32_t *)addr;
6689 	m = (u_int32_t *)&mask;
6690 	if ((a[0] & ~m[0]) || (a[1] & ~m[1])
6691 	 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
6692 		bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
6693 	}
6694 
6695 	switch (q.addr) {
6696 
6697 	case Q_DEFAULT:
6698 	case Q_HOST:
6699 		if (masklen != 128)
6700 			bpf_error(cstate, "Mask syntax for networks only");
6701 		/* FALLTHROUGH */
6702 
6703 	case Q_NET:
6704 		b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
6705 		cstate->ai = NULL;
6706 		freeaddrinfo(res);
6707 		return b;
6708 
6709 	default:
6710 		bpf_error(cstate, "invalid qualifier against IPv6 address");
6711 		/* NOTREACHED */
6712 	}
6713 	return NULL;
6714 }
6715 #endif /*INET6*/
6716 
6717 struct block *
gen_ecode(compiler_state_t * cstate,const u_char * eaddr,struct qual q)6718 gen_ecode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
6719 {
6720 	struct block *b, *tmp;
6721 
6722 	if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
6723 		switch (cstate->linktype) {
6724 		case DLT_EN10MB:
6725 		case DLT_NETANALYZER:
6726 		case DLT_NETANALYZER_TRANSPARENT:
6727 			tmp = gen_prevlinkhdr_check(cstate);
6728 			b = gen_ehostop(cstate, eaddr, (int)q.dir);
6729 			if (tmp != NULL)
6730 				gen_and(tmp, b);
6731 			return b;
6732 		case DLT_FDDI:
6733 			return gen_fhostop(cstate, eaddr, (int)q.dir);
6734 		case DLT_IEEE802:
6735 			return gen_thostop(cstate, eaddr, (int)q.dir);
6736 		case DLT_IEEE802_11:
6737 		case DLT_PRISM_HEADER:
6738 		case DLT_IEEE802_11_RADIO_AVS:
6739 		case DLT_IEEE802_11_RADIO:
6740 		case DLT_PPI:
6741 			return gen_wlanhostop(cstate, eaddr, (int)q.dir);
6742 		case DLT_IP_OVER_FC:
6743 			return gen_ipfchostop(cstate, eaddr, (int)q.dir);
6744 		default:
6745 			bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
6746 			break;
6747 		}
6748 	}
6749 	bpf_error(cstate, "ethernet address used in non-ether expression");
6750 	/* NOTREACHED */
6751 	return NULL;
6752 }
6753 
6754 void
sappend(s0,s1)6755 sappend(s0, s1)
6756 	struct slist *s0, *s1;
6757 {
6758 	/*
6759 	 * This is definitely not the best way to do this, but the
6760 	 * lists will rarely get long.
6761 	 */
6762 	while (s0->next)
6763 		s0 = s0->next;
6764 	s0->next = s1;
6765 }
6766 
6767 static struct slist *
xfer_to_x(compiler_state_t * cstate,struct arth * a)6768 xfer_to_x(compiler_state_t *cstate, struct arth *a)
6769 {
6770 	struct slist *s;
6771 
6772 	s = new_stmt(cstate, BPF_LDX|BPF_MEM);
6773 	s->s.k = a->regno;
6774 	return s;
6775 }
6776 
6777 static struct slist *
xfer_to_a(compiler_state_t * cstate,struct arth * a)6778 xfer_to_a(compiler_state_t *cstate, struct arth *a)
6779 {
6780 	struct slist *s;
6781 
6782 	s = new_stmt(cstate, BPF_LD|BPF_MEM);
6783 	s->s.k = a->regno;
6784 	return s;
6785 }
6786 
6787 /*
6788  * Modify "index" to use the value stored into its register as an
6789  * offset relative to the beginning of the header for the protocol
6790  * "proto", and allocate a register and put an item "size" bytes long
6791  * (1, 2, or 4) at that offset into that register, making it the register
6792  * for "index".
6793  */
6794 struct arth *
gen_load(compiler_state_t * cstate,int proto,struct arth * inst,int size)6795 gen_load(compiler_state_t *cstate, int proto, struct arth *inst, int size)
6796 {
6797 	struct slist *s, *tmp;
6798 	struct block *b;
6799 	int regno = alloc_reg(cstate);
6800 
6801 	free_reg(cstate, inst->regno);
6802 	switch (size) {
6803 
6804 	default:
6805 		bpf_error(cstate, "data size must be 1, 2, or 4");
6806 
6807 	case 1:
6808 		size = BPF_B;
6809 		break;
6810 
6811 	case 2:
6812 		size = BPF_H;
6813 		break;
6814 
6815 	case 4:
6816 		size = BPF_W;
6817 		break;
6818 	}
6819 	switch (proto) {
6820 	default:
6821 		bpf_error(cstate, "unsupported index operation");
6822 
6823 	case Q_RADIO:
6824 		/*
6825 		 * The offset is relative to the beginning of the packet
6826 		 * data, if we have a radio header.  (If we don't, this
6827 		 * is an error.)
6828 		 */
6829 		if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS &&
6830 		    cstate->linktype != DLT_IEEE802_11_RADIO &&
6831 		    cstate->linktype != DLT_PRISM_HEADER)
6832 			bpf_error(cstate, "radio information not present in capture");
6833 
6834 		/*
6835 		 * Load into the X register the offset computed into the
6836 		 * register specified by "index".
6837 		 */
6838 		s = xfer_to_x(cstate, inst);
6839 
6840 		/*
6841 		 * Load the item at that offset.
6842 		 */
6843 		tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6844 		sappend(s, tmp);
6845 		sappend(inst->s, s);
6846 		break;
6847 
6848 	case Q_LINK:
6849 		/*
6850 		 * The offset is relative to the beginning of
6851 		 * the link-layer header.
6852 		 *
6853 		 * XXX - what about ATM LANE?  Should the index be
6854 		 * relative to the beginning of the AAL5 frame, so
6855 		 * that 0 refers to the beginning of the LE Control
6856 		 * field, or relative to the beginning of the LAN
6857 		 * frame, so that 0 refers, for Ethernet LANE, to
6858 		 * the beginning of the destination address?
6859 		 */
6860 		s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr);
6861 
6862 		/*
6863 		 * If "s" is non-null, it has code to arrange that the
6864 		 * X register contains the length of the prefix preceding
6865 		 * the link-layer header.  Add to it the offset computed
6866 		 * into the register specified by "index", and move that
6867 		 * into the X register.  Otherwise, just load into the X
6868 		 * register the offset computed into the register specified
6869 		 * by "index".
6870 		 */
6871 		if (s != NULL) {
6872 			sappend(s, xfer_to_a(cstate, inst));
6873 			sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
6874 			sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
6875 		} else
6876 			s = xfer_to_x(cstate, inst);
6877 
6878 		/*
6879 		 * Load the item at the sum of the offset we've put in the
6880 		 * X register and the offset of the start of the link
6881 		 * layer header (which is 0 if the radio header is
6882 		 * variable-length; that header length is what we put
6883 		 * into the X register and then added to the index).
6884 		 */
6885 		tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6886 		tmp->s.k = cstate->off_linkhdr.constant_part;
6887 		sappend(s, tmp);
6888 		sappend(inst->s, s);
6889 		break;
6890 
6891 	case Q_IP:
6892 	case Q_ARP:
6893 	case Q_RARP:
6894 	case Q_ATALK:
6895 	case Q_DECNET:
6896 	case Q_SCA:
6897 	case Q_LAT:
6898 	case Q_MOPRC:
6899 	case Q_MOPDL:
6900 	case Q_IPV6:
6901 		/*
6902 		 * The offset is relative to the beginning of
6903 		 * the network-layer header.
6904 		 * XXX - are there any cases where we want
6905 		 * cstate->off_nl_nosnap?
6906 		 */
6907 		s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
6908 
6909 		/*
6910 		 * If "s" is non-null, it has code to arrange that the
6911 		 * X register contains the variable part of the offset
6912 		 * of the link-layer payload.  Add to it the offset
6913 		 * computed into the register specified by "index",
6914 		 * and move that into the X register.  Otherwise, just
6915 		 * load into the X register the offset computed into
6916 		 * the register specified by "index".
6917 		 */
6918 		if (s != NULL) {
6919 			sappend(s, xfer_to_a(cstate, inst));
6920 			sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
6921 			sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
6922 		} else
6923 			s = xfer_to_x(cstate, inst);
6924 
6925 		/*
6926 		 * Load the item at the sum of the offset we've put in the
6927 		 * X register, the offset of the start of the network
6928 		 * layer header from the beginning of the link-layer
6929 		 * payload, and the constant part of the offset of the
6930 		 * start of the link-layer payload.
6931 		 */
6932 		tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6933 		tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6934 		sappend(s, tmp);
6935 		sappend(inst->s, s);
6936 
6937 		/*
6938 		 * Do the computation only if the packet contains
6939 		 * the protocol in question.
6940 		 */
6941 		b = gen_proto_abbrev(cstate, proto);
6942 		if (inst->b)
6943 			gen_and(inst->b, b);
6944 		inst->b = b;
6945 		break;
6946 
6947 	case Q_SCTP:
6948 	case Q_TCP:
6949 	case Q_UDP:
6950 	case Q_ICMP:
6951 	case Q_IGMP:
6952 	case Q_IGRP:
6953 	case Q_PIM:
6954 	case Q_VRRP:
6955 	case Q_CARP:
6956 		/*
6957 		 * The offset is relative to the beginning of
6958 		 * the transport-layer header.
6959 		 *
6960 		 * Load the X register with the length of the IPv4 header
6961 		 * (plus the offset of the link-layer header, if it's
6962 		 * a variable-length header), in bytes.
6963 		 *
6964 		 * XXX - are there any cases where we want
6965 		 * cstate->off_nl_nosnap?
6966 		 * XXX - we should, if we're built with
6967 		 * IPv6 support, generate code to load either
6968 		 * IPv4, IPv6, or both, as appropriate.
6969 		 */
6970 		s = gen_loadx_iphdrlen(cstate);
6971 
6972 		/*
6973 		 * The X register now contains the sum of the variable
6974 		 * part of the offset of the link-layer payload and the
6975 		 * length of the network-layer header.
6976 		 *
6977 		 * Load into the A register the offset relative to
6978 		 * the beginning of the transport layer header,
6979 		 * add the X register to that, move that to the
6980 		 * X register, and load with an offset from the
6981 		 * X register equal to the sum of the constant part of
6982 		 * the offset of the link-layer payload and the offset,
6983 		 * relative to the beginning of the link-layer payload,
6984 		 * of the network-layer header.
6985 		 */
6986 		sappend(s, xfer_to_a(cstate, inst));
6987 		sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
6988 		sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
6989 		sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size));
6990 		tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6991 		sappend(inst->s, s);
6992 
6993 		/*
6994 		 * Do the computation only if the packet contains
6995 		 * the protocol in question - which is true only
6996 		 * if this is an IP datagram and is the first or
6997 		 * only fragment of that datagram.
6998 		 */
6999 		gen_and(gen_proto_abbrev(cstate, proto), b = gen_ipfrag(cstate));
7000 		if (inst->b)
7001 			gen_and(inst->b, b);
7002 		gen_and(gen_proto_abbrev(cstate, Q_IP), b);
7003 		inst->b = b;
7004 		break;
7005 	case Q_ICMPV6:
7006 		bpf_error(cstate, "IPv6 upper-layer protocol is not supported by proto[x]");
7007 		/*NOTREACHED*/
7008 	}
7009 	inst->regno = regno;
7010 	s = new_stmt(cstate, BPF_ST);
7011 	s->s.k = regno;
7012 	sappend(inst->s, s);
7013 
7014 	return inst;
7015 }
7016 
7017 struct block *
gen_relation(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1,int reversed)7018 gen_relation(compiler_state_t *cstate, int code, struct arth *a0,
7019     struct arth *a1, int reversed)
7020 {
7021 	struct slist *s0, *s1, *s2;
7022 	struct block *b, *tmp;
7023 
7024 	s0 = xfer_to_x(cstate, a1);
7025 	s1 = xfer_to_a(cstate, a0);
7026 	if (code == BPF_JEQ) {
7027 		s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X);
7028 		b = new_block(cstate, JMP(code));
7029 		sappend(s1, s2);
7030 	}
7031 	else
7032 		b = new_block(cstate, BPF_JMP|code|BPF_X);
7033 	if (reversed)
7034 		gen_not(b);
7035 
7036 	sappend(s0, s1);
7037 	sappend(a1->s, s0);
7038 	sappend(a0->s, a1->s);
7039 
7040 	b->stmts = a0->s;
7041 
7042 	free_reg(cstate, a0->regno);
7043 	free_reg(cstate, a1->regno);
7044 
7045 	/* 'and' together protocol checks */
7046 	if (a0->b) {
7047 		if (a1->b) {
7048 			gen_and(a0->b, tmp = a1->b);
7049 		}
7050 		else
7051 			tmp = a0->b;
7052 	} else
7053 		tmp = a1->b;
7054 
7055 	if (tmp)
7056 		gen_and(tmp, b);
7057 
7058 	return b;
7059 }
7060 
7061 struct arth *
gen_loadlen(compiler_state_t * cstate)7062 gen_loadlen(compiler_state_t *cstate)
7063 {
7064 	int regno = alloc_reg(cstate);
7065 	struct arth *a = (struct arth *)newchunk(cstate, sizeof(*a));
7066 	struct slist *s;
7067 
7068 	s = new_stmt(cstate, BPF_LD|BPF_LEN);
7069 	s->next = new_stmt(cstate, BPF_ST);
7070 	s->next->s.k = regno;
7071 	a->s = s;
7072 	a->regno = regno;
7073 
7074 	return a;
7075 }
7076 
7077 struct arth *
gen_loadi(compiler_state_t * cstate,int val)7078 gen_loadi(compiler_state_t *cstate, int val)
7079 {
7080 	struct arth *a;
7081 	struct slist *s;
7082 	int reg;
7083 
7084 	a = (struct arth *)newchunk(cstate, sizeof(*a));
7085 
7086 	reg = alloc_reg(cstate);
7087 
7088 	s = new_stmt(cstate, BPF_LD|BPF_IMM);
7089 	s->s.k = val;
7090 	s->next = new_stmt(cstate, BPF_ST);
7091 	s->next->s.k = reg;
7092 	a->s = s;
7093 	a->regno = reg;
7094 
7095 	return a;
7096 }
7097 
7098 struct arth *
gen_neg(compiler_state_t * cstate,struct arth * a)7099 gen_neg(compiler_state_t *cstate, struct arth *a)
7100 {
7101 	struct slist *s;
7102 
7103 	s = xfer_to_a(cstate, a);
7104 	sappend(a->s, s);
7105 	s = new_stmt(cstate, BPF_ALU|BPF_NEG);
7106 	s->s.k = 0;
7107 	sappend(a->s, s);
7108 	s = new_stmt(cstate, BPF_ST);
7109 	s->s.k = a->regno;
7110 	sappend(a->s, s);
7111 
7112 	return a;
7113 }
7114 
7115 struct arth *
gen_arth(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1)7116 gen_arth(compiler_state_t *cstate, int code, struct arth *a0,
7117     struct arth *a1)
7118 {
7119 	struct slist *s0, *s1, *s2;
7120 
7121 	/*
7122 	 * Disallow division by, or modulus by, zero; we do this here
7123 	 * so that it gets done even if the optimizer is disabled.
7124 	 */
7125 	if (code == BPF_DIV) {
7126 		if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7127 			bpf_error(cstate, "division by zero");
7128 	} else if (code == BPF_MOD) {
7129 		if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7130 			bpf_error(cstate, "modulus by zero");
7131 	}
7132 	s0 = xfer_to_x(cstate, a1);
7133 	s1 = xfer_to_a(cstate, a0);
7134 	s2 = new_stmt(cstate, BPF_ALU|BPF_X|code);
7135 
7136 	sappend(s1, s2);
7137 	sappend(s0, s1);
7138 	sappend(a1->s, s0);
7139 	sappend(a0->s, a1->s);
7140 
7141 	free_reg(cstate, a0->regno);
7142 	free_reg(cstate, a1->regno);
7143 
7144 	s0 = new_stmt(cstate, BPF_ST);
7145 	a0->regno = s0->s.k = alloc_reg(cstate);
7146 	sappend(a0->s, s0);
7147 
7148 	return a0;
7149 }
7150 
7151 /*
7152  * Initialize the table of used registers and the current register.
7153  */
7154 static void
init_regs(compiler_state_t * cstate)7155 init_regs(compiler_state_t *cstate)
7156 {
7157 	cstate->curreg = 0;
7158 	memset(cstate->regused, 0, sizeof cstate->regused);
7159 }
7160 
7161 /*
7162  * Return the next free register.
7163  */
7164 static int
alloc_reg(compiler_state_t * cstate)7165 alloc_reg(compiler_state_t *cstate)
7166 {
7167 	int n = BPF_MEMWORDS;
7168 
7169 	while (--n >= 0) {
7170 		if (cstate->regused[cstate->curreg])
7171 			cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS;
7172 		else {
7173 			cstate->regused[cstate->curreg] = 1;
7174 			return cstate->curreg;
7175 		}
7176 	}
7177 	bpf_error(cstate, "too many registers needed to evaluate expression");
7178 	/* NOTREACHED */
7179 	return 0;
7180 }
7181 
7182 /*
7183  * Return a register to the table so it can
7184  * be used later.
7185  */
7186 static void
free_reg(compiler_state_t * cstate,int n)7187 free_reg(compiler_state_t *cstate, int n)
7188 {
7189 	cstate->regused[n] = 0;
7190 }
7191 
7192 static struct block *
gen_len(compiler_state_t * cstate,int jmp,int n)7193 gen_len(compiler_state_t *cstate, int jmp, int n)
7194 {
7195 	struct slist *s;
7196 	struct block *b;
7197 
7198 	s = new_stmt(cstate, BPF_LD|BPF_LEN);
7199 	b = new_block(cstate, JMP(jmp));
7200 	b->stmts = s;
7201 	b->s.k = n;
7202 
7203 	return b;
7204 }
7205 
7206 struct block *
gen_greater(compiler_state_t * cstate,int n)7207 gen_greater(compiler_state_t *cstate, int n)
7208 {
7209 	return gen_len(cstate, BPF_JGE, n);
7210 }
7211 
7212 /*
7213  * Actually, this is less than or equal.
7214  */
7215 struct block *
gen_less(compiler_state_t * cstate,int n)7216 gen_less(compiler_state_t *cstate, int n)
7217 {
7218 	struct block *b;
7219 
7220 	b = gen_len(cstate, BPF_JGT, n);
7221 	gen_not(b);
7222 
7223 	return b;
7224 }
7225 
7226 /*
7227  * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
7228  * the beginning of the link-layer header.
7229  * XXX - that means you can't test values in the radiotap header, but
7230  * as that header is difficult if not impossible to parse generally
7231  * without a loop, that might not be a severe problem.  A new keyword
7232  * "radio" could be added for that, although what you'd really want
7233  * would be a way of testing particular radio header values, which
7234  * would generate code appropriate to the radio header in question.
7235  */
7236 struct block *
gen_byteop(compiler_state_t * cstate,int op,int idx,int val)7237 gen_byteop(compiler_state_t *cstate, int op, int idx, int val)
7238 {
7239 	struct block *b;
7240 	struct slist *s;
7241 
7242 	switch (op) {
7243 	default:
7244 		abort();
7245 
7246 	case '=':
7247 		return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7248 
7249 	case '<':
7250 		b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7251 		return b;
7252 
7253 	case '>':
7254 		b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7255 		return b;
7256 
7257 	case '|':
7258 		s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K);
7259 		break;
7260 
7261 	case '&':
7262 		s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
7263 		break;
7264 	}
7265 	s->s.k = val;
7266 	b = new_block(cstate, JMP(BPF_JEQ));
7267 	b->stmts = s;
7268 	gen_not(b);
7269 
7270 	return b;
7271 }
7272 
7273 static const u_char abroadcast[] = { 0x0 };
7274 
7275 struct block *
gen_broadcast(compiler_state_t * cstate,int proto)7276 gen_broadcast(compiler_state_t *cstate, int proto)
7277 {
7278 	bpf_u_int32 hostmask;
7279 	struct block *b0, *b1, *b2;
7280 	static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
7281 
7282 	switch (proto) {
7283 
7284 	case Q_DEFAULT:
7285 	case Q_LINK:
7286 		switch (cstate->linktype) {
7287 		case DLT_ARCNET:
7288 		case DLT_ARCNET_LINUX:
7289 			return gen_ahostop(cstate, abroadcast, Q_DST);
7290 		case DLT_EN10MB:
7291 		case DLT_NETANALYZER:
7292 		case DLT_NETANALYZER_TRANSPARENT:
7293 			b1 = gen_prevlinkhdr_check(cstate);
7294 			b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
7295 			if (b1 != NULL)
7296 				gen_and(b1, b0);
7297 			return b0;
7298 		case DLT_FDDI:
7299 			return gen_fhostop(cstate, ebroadcast, Q_DST);
7300 		case DLT_IEEE802:
7301 			return gen_thostop(cstate, ebroadcast, Q_DST);
7302 		case DLT_IEEE802_11:
7303 		case DLT_PRISM_HEADER:
7304 		case DLT_IEEE802_11_RADIO_AVS:
7305 		case DLT_IEEE802_11_RADIO:
7306 		case DLT_PPI:
7307 			return gen_wlanhostop(cstate, ebroadcast, Q_DST);
7308 		case DLT_IP_OVER_FC:
7309 			return gen_ipfchostop(cstate, ebroadcast, Q_DST);
7310 		default:
7311 			bpf_error(cstate, "not a broadcast link");
7312 		}
7313 		break;
7314 
7315 	case Q_IP:
7316 		/*
7317 		 * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
7318 		 * as an indication that we don't know the netmask, and fail
7319 		 * in that case.
7320 		 */
7321 		if (cstate->netmask == PCAP_NETMASK_UNKNOWN)
7322 			bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported");
7323 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
7324 		hostmask = ~cstate->netmask;
7325 		b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, (bpf_int32)0, hostmask);
7326 		b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W,
7327 			      (bpf_int32)(~0 & hostmask), hostmask);
7328 		gen_or(b1, b2);
7329 		gen_and(b0, b2);
7330 		return b2;
7331 	}
7332 	bpf_error(cstate, "only link-layer/IP broadcast filters supported");
7333 	/* NOTREACHED */
7334 	return NULL;
7335 }
7336 
7337 /*
7338  * Generate code to test the low-order bit of a MAC address (that's
7339  * the bottom bit of the *first* byte).
7340  */
7341 static struct block *
gen_mac_multicast(compiler_state_t * cstate,int offset)7342 gen_mac_multicast(compiler_state_t *cstate, int offset)
7343 {
7344 	register struct block *b0;
7345 	register struct slist *s;
7346 
7347 	/* link[offset] & 1 != 0 */
7348 	s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B);
7349 	b0 = new_block(cstate, JMP(BPF_JSET));
7350 	b0->s.k = 1;
7351 	b0->stmts = s;
7352 	return b0;
7353 }
7354 
7355 struct block *
gen_multicast(compiler_state_t * cstate,int proto)7356 gen_multicast(compiler_state_t *cstate, int proto)
7357 {
7358 	register struct block *b0, *b1, *b2;
7359 	register struct slist *s;
7360 
7361 	switch (proto) {
7362 
7363 	case Q_DEFAULT:
7364 	case Q_LINK:
7365 		switch (cstate->linktype) {
7366 		case DLT_ARCNET:
7367 		case DLT_ARCNET_LINUX:
7368 			/* all ARCnet multicasts use the same address */
7369 			return gen_ahostop(cstate, abroadcast, Q_DST);
7370 		case DLT_EN10MB:
7371 		case DLT_NETANALYZER:
7372 		case DLT_NETANALYZER_TRANSPARENT:
7373 			b1 = gen_prevlinkhdr_check(cstate);
7374 			/* ether[0] & 1 != 0 */
7375 			b0 = gen_mac_multicast(cstate, 0);
7376 			if (b1 != NULL)
7377 				gen_and(b1, b0);
7378 			return b0;
7379 		case DLT_FDDI:
7380 			/*
7381 			 * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
7382 			 *
7383 			 * XXX - was that referring to bit-order issues?
7384 			 */
7385 			/* fddi[1] & 1 != 0 */
7386 			return gen_mac_multicast(cstate, 1);
7387 		case DLT_IEEE802:
7388 			/* tr[2] & 1 != 0 */
7389 			return gen_mac_multicast(cstate, 2);
7390 		case DLT_IEEE802_11:
7391 		case DLT_PRISM_HEADER:
7392 		case DLT_IEEE802_11_RADIO_AVS:
7393 		case DLT_IEEE802_11_RADIO:
7394 		case DLT_PPI:
7395 			/*
7396 			 * Oh, yuk.
7397 			 *
7398 			 *	For control frames, there is no DA.
7399 			 *
7400 			 *	For management frames, DA is at an
7401 			 *	offset of 4 from the beginning of
7402 			 *	the packet.
7403 			 *
7404 			 *	For data frames, DA is at an offset
7405 			 *	of 4 from the beginning of the packet
7406 			 *	if To DS is clear and at an offset of
7407 			 *	16 from the beginning of the packet
7408 			 *	if To DS is set.
7409 			 */
7410 
7411 			/*
7412 			 * Generate the tests to be done for data frames.
7413 			 *
7414 			 * First, check for To DS set, i.e. "link[1] & 0x01".
7415 			 */
7416 			s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7417 			b1 = new_block(cstate, JMP(BPF_JSET));
7418 			b1->s.k = 0x01;	/* To DS */
7419 			b1->stmts = s;
7420 
7421 			/*
7422 			 * If To DS is set, the DA is at 16.
7423 			 */
7424 			b0 = gen_mac_multicast(cstate, 16);
7425 			gen_and(b1, b0);
7426 
7427 			/*
7428 			 * Now, check for To DS not set, i.e. check
7429 			 * "!(link[1] & 0x01)".
7430 			 */
7431 			s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7432 			b2 = new_block(cstate, JMP(BPF_JSET));
7433 			b2->s.k = 0x01;	/* To DS */
7434 			b2->stmts = s;
7435 			gen_not(b2);
7436 
7437 			/*
7438 			 * If To DS is not set, the DA is at 4.
7439 			 */
7440 			b1 = gen_mac_multicast(cstate, 4);
7441 			gen_and(b2, b1);
7442 
7443 			/*
7444 			 * Now OR together the last two checks.  That gives
7445 			 * the complete set of checks for data frames.
7446 			 */
7447 			gen_or(b1, b0);
7448 
7449 			/*
7450 			 * Now check for a data frame.
7451 			 * I.e, check "link[0] & 0x08".
7452 			 */
7453 			s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7454 			b1 = new_block(cstate, JMP(BPF_JSET));
7455 			b1->s.k = 0x08;
7456 			b1->stmts = s;
7457 
7458 			/*
7459 			 * AND that with the checks done for data frames.
7460 			 */
7461 			gen_and(b1, b0);
7462 
7463 			/*
7464 			 * If the high-order bit of the type value is 0, this
7465 			 * is a management frame.
7466 			 * I.e, check "!(link[0] & 0x08)".
7467 			 */
7468 			s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7469 			b2 = new_block(cstate, JMP(BPF_JSET));
7470 			b2->s.k = 0x08;
7471 			b2->stmts = s;
7472 			gen_not(b2);
7473 
7474 			/*
7475 			 * For management frames, the DA is at 4.
7476 			 */
7477 			b1 = gen_mac_multicast(cstate, 4);
7478 			gen_and(b2, b1);
7479 
7480 			/*
7481 			 * OR that with the checks done for data frames.
7482 			 * That gives the checks done for management and
7483 			 * data frames.
7484 			 */
7485 			gen_or(b1, b0);
7486 
7487 			/*
7488 			 * If the low-order bit of the type value is 1,
7489 			 * this is either a control frame or a frame
7490 			 * with a reserved type, and thus not a
7491 			 * frame with an SA.
7492 			 *
7493 			 * I.e., check "!(link[0] & 0x04)".
7494 			 */
7495 			s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7496 			b1 = new_block(cstate, JMP(BPF_JSET));
7497 			b1->s.k = 0x04;
7498 			b1->stmts = s;
7499 			gen_not(b1);
7500 
7501 			/*
7502 			 * AND that with the checks for data and management
7503 			 * frames.
7504 			 */
7505 			gen_and(b1, b0);
7506 			return b0;
7507 		case DLT_IP_OVER_FC:
7508 			b0 = gen_mac_multicast(cstate, 2);
7509 			return b0;
7510 		default:
7511 			break;
7512 		}
7513 		/* Link not known to support multicasts */
7514 		break;
7515 
7516 	case Q_IP:
7517 		b0 = gen_linktype(cstate, ETHERTYPE_IP);
7518 		b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, (bpf_int32)224);
7519 		gen_and(b0, b1);
7520 		return b1;
7521 
7522 	case Q_IPV6:
7523 		b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
7524 		b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, (bpf_int32)255);
7525 		gen_and(b0, b1);
7526 		return b1;
7527 	}
7528 	bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
7529 	/* NOTREACHED */
7530 	return NULL;
7531 }
7532 
7533 /*
7534  * Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
7535  * Outbound traffic is sent by this machine, while inbound traffic is
7536  * sent by a remote machine (and may include packets destined for a
7537  * unicast or multicast link-layer address we are not subscribing to).
7538  * These are the same definitions implemented by pcap_setdirection().
7539  * Capturing only unicast traffic destined for this host is probably
7540  * better accomplished using a higher-layer filter.
7541  */
7542 struct block *
gen_inbound(compiler_state_t * cstate,int dir)7543 gen_inbound(compiler_state_t *cstate, int dir)
7544 {
7545 	register struct block *b0;
7546 
7547 	/*
7548 	 * Only some data link types support inbound/outbound qualifiers.
7549 	 */
7550 	switch (cstate->linktype) {
7551 	case DLT_SLIP:
7552 		b0 = gen_relation(cstate, BPF_JEQ,
7553 			  gen_load(cstate, Q_LINK, gen_loadi(cstate, 0), 1),
7554 			  gen_loadi(cstate, 0),
7555 			  dir);
7556 		break;
7557 
7558 	case DLT_IPNET:
7559 		if (dir) {
7560 			/* match outgoing packets */
7561 			b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND);
7562 		} else {
7563 			/* match incoming packets */
7564 			b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND);
7565 		}
7566 		break;
7567 
7568 	case DLT_LINUX_SLL:
7569 		/* match outgoing packets */
7570 		b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING);
7571 		if (!dir) {
7572 			/* to filter on inbound traffic, invert the match */
7573 			gen_not(b0);
7574 		}
7575 		break;
7576 
7577 #ifdef HAVE_NET_PFVAR_H
7578 	case DLT_PFLOG:
7579 		b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
7580 		    (bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
7581 		break;
7582 #endif
7583 
7584 	case DLT_PPP_PPPD:
7585 		if (dir) {
7586 			/* match outgoing packets */
7587 			b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT);
7588 		} else {
7589 			/* match incoming packets */
7590 			b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN);
7591 		}
7592 		break;
7593 
7594         case DLT_JUNIPER_MFR:
7595         case DLT_JUNIPER_MLFR:
7596         case DLT_JUNIPER_MLPPP:
7597 	case DLT_JUNIPER_ATM1:
7598 	case DLT_JUNIPER_ATM2:
7599 	case DLT_JUNIPER_PPPOE:
7600 	case DLT_JUNIPER_PPPOE_ATM:
7601         case DLT_JUNIPER_GGSN:
7602         case DLT_JUNIPER_ES:
7603         case DLT_JUNIPER_MONITOR:
7604         case DLT_JUNIPER_SERVICES:
7605         case DLT_JUNIPER_ETHER:
7606         case DLT_JUNIPER_PPP:
7607         case DLT_JUNIPER_FRELAY:
7608         case DLT_JUNIPER_CHDLC:
7609         case DLT_JUNIPER_VP:
7610         case DLT_JUNIPER_ST:
7611         case DLT_JUNIPER_ISM:
7612         case DLT_JUNIPER_VS:
7613         case DLT_JUNIPER_SRX_E2E:
7614         case DLT_JUNIPER_FIBRECHANNEL:
7615 	case DLT_JUNIPER_ATM_CEMIC:
7616 
7617 		/* juniper flags (including direction) are stored
7618 		 * the byte after the 3-byte magic number */
7619 		if (dir) {
7620 			/* match outgoing packets */
7621 			b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01);
7622 		} else {
7623 			/* match incoming packets */
7624 			b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01);
7625 		}
7626 		break;
7627 
7628 	default:
7629 		/*
7630 		 * If we have packet meta-data indicating a direction,
7631 		 * check it, otherwise give up as this link-layer type
7632 		 * has nothing in the packet data.
7633 		 */
7634 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
7635 		/*
7636 		 * This is Linux with PF_PACKET support.
7637 		 * If this is a *live* capture, we can look at
7638 		 * special meta-data in the filter expression;
7639 		 * if it's a savefile, we can't.
7640 		 */
7641 		if (cstate->bpf_pcap->rfile != NULL) {
7642 			/* We have a FILE *, so this is a savefile */
7643 			bpf_error(cstate, "inbound/outbound not supported on linktype %d when reading savefiles",
7644 			    cstate->linktype);
7645 			b0 = NULL;
7646 			/* NOTREACHED */
7647 		}
7648 		/* match outgoing packets */
7649 		b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
7650 		             PACKET_OUTGOING);
7651 		if (!dir) {
7652 			/* to filter on inbound traffic, invert the match */
7653 			gen_not(b0);
7654 		}
7655 #else /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7656 		bpf_error(cstate, "inbound/outbound not supported on linktype %d",
7657 		    cstate->linktype);
7658 		b0 = NULL;
7659 		/* NOTREACHED */
7660 #endif /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7661 	}
7662 	return (b0);
7663 }
7664 
7665 #ifdef HAVE_NET_PFVAR_H
7666 /* PF firewall log matched interface */
7667 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname)7668 gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
7669 {
7670 	struct block *b0;
7671 	u_int len, off;
7672 
7673 	if (cstate->linktype != DLT_PFLOG) {
7674 		bpf_error(cstate, "ifname supported only on PF linktype");
7675 		/* NOTREACHED */
7676 	}
7677 	len = sizeof(((struct pfloghdr *)0)->ifname);
7678 	off = offsetof(struct pfloghdr, ifname);
7679 	if (strlen(ifname) >= len) {
7680 		bpf_error(cstate, "ifname interface names can only be %d characters",
7681 		    len-1);
7682 		/* NOTREACHED */
7683 	}
7684 	b0 = gen_bcmp(cstate, OR_LINKHDR, off, strlen(ifname), (const u_char *)ifname);
7685 	return (b0);
7686 }
7687 
7688 /* PF firewall log ruleset name */
7689 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset)7690 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
7691 {
7692 	struct block *b0;
7693 
7694 	if (cstate->linktype != DLT_PFLOG) {
7695 		bpf_error(cstate, "ruleset supported only on PF linktype");
7696 		/* NOTREACHED */
7697 	}
7698 
7699 	if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
7700 		bpf_error(cstate, "ruleset names can only be %ld characters",
7701 		    (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
7702 		/* NOTREACHED */
7703 	}
7704 
7705 	b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
7706 	    strlen(ruleset), (const u_char *)ruleset);
7707 	return (b0);
7708 }
7709 
7710 /* PF firewall log rule number */
7711 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr)7712 gen_pf_rnr(compiler_state_t *cstate, int rnr)
7713 {
7714 	struct block *b0;
7715 
7716 	if (cstate->linktype != DLT_PFLOG) {
7717 		bpf_error(cstate, "rnr supported only on PF linktype");
7718 		/* NOTREACHED */
7719 	}
7720 
7721 	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
7722 		 (bpf_int32)rnr);
7723 	return (b0);
7724 }
7725 
7726 /* PF firewall log sub-rule number */
7727 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr)7728 gen_pf_srnr(compiler_state_t *cstate, int srnr)
7729 {
7730 	struct block *b0;
7731 
7732 	if (cstate->linktype != DLT_PFLOG) {
7733 		bpf_error(cstate, "srnr supported only on PF linktype");
7734 		/* NOTREACHED */
7735 	}
7736 
7737 	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
7738 	    (bpf_int32)srnr);
7739 	return (b0);
7740 }
7741 
7742 /* PF firewall log reason code */
7743 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason)7744 gen_pf_reason(compiler_state_t *cstate, int reason)
7745 {
7746 	struct block *b0;
7747 
7748 	if (cstate->linktype != DLT_PFLOG) {
7749 		bpf_error(cstate, "reason supported only on PF linktype");
7750 		/* NOTREACHED */
7751 	}
7752 
7753 	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
7754 	    (bpf_int32)reason);
7755 	return (b0);
7756 }
7757 
7758 /* PF firewall log action */
7759 struct block *
gen_pf_action(compiler_state_t * cstate,int action)7760 gen_pf_action(compiler_state_t *cstate, int action)
7761 {
7762 	struct block *b0;
7763 
7764 	if (cstate->linktype != DLT_PFLOG) {
7765 		bpf_error(cstate, "action supported only on PF linktype");
7766 		/* NOTREACHED */
7767 	}
7768 
7769 	b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
7770 	    (bpf_int32)action);
7771 	return (b0);
7772 }
7773 #else /* !HAVE_NET_PFVAR_H */
7774 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname)7775 gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
7776 {
7777 	bpf_error(cstate, "libpcap was compiled without pf support");
7778 	/* NOTREACHED */
7779 	return (NULL);
7780 }
7781 
7782 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset)7783 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
7784 {
7785 	bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7786 	/* NOTREACHED */
7787 	return (NULL);
7788 }
7789 
7790 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr)7791 gen_pf_rnr(compiler_state_t *cstate, int rnr)
7792 {
7793 	bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7794 	/* NOTREACHED */
7795 	return (NULL);
7796 }
7797 
7798 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr)7799 gen_pf_srnr(compiler_state_t *cstate, int srnr)
7800 {
7801 	bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7802 	/* NOTREACHED */
7803 	return (NULL);
7804 }
7805 
7806 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason)7807 gen_pf_reason(compiler_state_t *cstate, int reason)
7808 {
7809 	bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7810 	/* NOTREACHED */
7811 	return (NULL);
7812 }
7813 
7814 struct block *
gen_pf_action(compiler_state_t * cstate,int action)7815 gen_pf_action(compiler_state_t *cstate, int action)
7816 {
7817 	bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7818 	/* NOTREACHED */
7819 	return (NULL);
7820 }
7821 #endif /* HAVE_NET_PFVAR_H */
7822 
7823 /* IEEE 802.11 wireless header */
7824 struct block *
gen_p80211_type(compiler_state_t * cstate,int type,int mask)7825 gen_p80211_type(compiler_state_t *cstate, int type, int mask)
7826 {
7827 	struct block *b0;
7828 
7829 	switch (cstate->linktype) {
7830 
7831 	case DLT_IEEE802_11:
7832 	case DLT_PRISM_HEADER:
7833 	case DLT_IEEE802_11_RADIO_AVS:
7834 	case DLT_IEEE802_11_RADIO:
7835 		b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, (bpf_int32)type,
7836 		    (bpf_int32)mask);
7837 		break;
7838 
7839 	default:
7840 		bpf_error(cstate, "802.11 link-layer types supported only on 802.11");
7841 		/* NOTREACHED */
7842 	}
7843 
7844 	return (b0);
7845 }
7846 
7847 struct block *
gen_p80211_fcdir(compiler_state_t * cstate,int fcdir)7848 gen_p80211_fcdir(compiler_state_t *cstate, int fcdir)
7849 {
7850 	struct block *b0;
7851 
7852 	switch (cstate->linktype) {
7853 
7854 	case DLT_IEEE802_11:
7855 	case DLT_PRISM_HEADER:
7856 	case DLT_IEEE802_11_RADIO_AVS:
7857 	case DLT_IEEE802_11_RADIO:
7858 		break;
7859 
7860 	default:
7861 		bpf_error(cstate, "frame direction supported only with 802.11 headers");
7862 		/* NOTREACHED */
7863 	}
7864 
7865 	b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, (bpf_int32)fcdir,
7866 		(bpf_u_int32)IEEE80211_FC1_DIR_MASK);
7867 
7868 	return (b0);
7869 }
7870 
7871 struct block *
gen_acode(compiler_state_t * cstate,const u_char * eaddr,struct qual q)7872 gen_acode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
7873 {
7874 	switch (cstate->linktype) {
7875 
7876 	case DLT_ARCNET:
7877 	case DLT_ARCNET_LINUX:
7878 		if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
7879 		    q.proto == Q_LINK)
7880 			return (gen_ahostop(cstate, eaddr, (int)q.dir));
7881 		else {
7882 			bpf_error(cstate, "ARCnet address used in non-arc expression");
7883 			/* NOTREACHED */
7884 		}
7885 		break;
7886 
7887 	default:
7888 		bpf_error(cstate, "aid supported only on ARCnet");
7889 		/* NOTREACHED */
7890 	}
7891 	bpf_error(cstate, "ARCnet address used in non-arc expression");
7892 	/* NOTREACHED */
7893 	return NULL;
7894 }
7895 
7896 static struct block *
gen_ahostop(compiler_state_t * cstate,const u_char * eaddr,int dir)7897 gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
7898 {
7899 	register struct block *b0, *b1;
7900 
7901 	switch (dir) {
7902 	/* src comes first, different from Ethernet */
7903 	case Q_SRC:
7904 		return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr);
7905 
7906 	case Q_DST:
7907 		return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr);
7908 
7909 	case Q_AND:
7910 		b0 = gen_ahostop(cstate, eaddr, Q_SRC);
7911 		b1 = gen_ahostop(cstate, eaddr, Q_DST);
7912 		gen_and(b0, b1);
7913 		return b1;
7914 
7915 	case Q_DEFAULT:
7916 	case Q_OR:
7917 		b0 = gen_ahostop(cstate, eaddr, Q_SRC);
7918 		b1 = gen_ahostop(cstate, eaddr, Q_DST);
7919 		gen_or(b0, b1);
7920 		return b1;
7921 
7922 	case Q_ADDR1:
7923 		bpf_error(cstate, "'addr1' is only supported on 802.11");
7924 		break;
7925 
7926 	case Q_ADDR2:
7927 		bpf_error(cstate, "'addr2' is only supported on 802.11");
7928 		break;
7929 
7930 	case Q_ADDR3:
7931 		bpf_error(cstate, "'addr3' is only supported on 802.11");
7932 		break;
7933 
7934 	case Q_ADDR4:
7935 		bpf_error(cstate, "'addr4' is only supported on 802.11");
7936 		break;
7937 
7938 	case Q_RA:
7939 		bpf_error(cstate, "'ra' is only supported on 802.11");
7940 		break;
7941 
7942 	case Q_TA:
7943 		bpf_error(cstate, "'ta' is only supported on 802.11");
7944 		break;
7945 	}
7946 	abort();
7947 	/* NOTREACHED */
7948 }
7949 
7950 #if defined(SKF_AD_VLAN_TAG) && defined(SKF_AD_VLAN_TAG_PRESENT)
7951 static struct block *
gen_vlan_bpf_extensions(compiler_state_t * cstate,int vlan_num)7952 gen_vlan_bpf_extensions(compiler_state_t *cstate, int vlan_num)
7953 {
7954         struct block *b0, *b1;
7955         struct slist *s;
7956 
7957         /* generate new filter code based on extracting packet
7958          * metadata */
7959         s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
7960         s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
7961 
7962         b0 = new_block(cstate, JMP(BPF_JEQ));
7963         b0->stmts = s;
7964         b0->s.k = 1;
7965 
7966         if (vlan_num >= 0) {
7967                 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
7968                 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
7969 
7970                 b1 = new_block(cstate, JMP(BPF_JEQ));
7971                 b1->stmts = s;
7972                 b1->s.k = (bpf_int32) vlan_num;
7973 
7974                 gen_and(b0,b1);
7975                 b0 = b1;
7976         }
7977 
7978         return b0;
7979 }
7980 #endif
7981 
7982 static struct block *
gen_vlan_no_bpf_extensions(compiler_state_t * cstate,int vlan_num)7983 gen_vlan_no_bpf_extensions(compiler_state_t *cstate, int vlan_num)
7984 {
7985         struct block *b0, *b1;
7986 
7987         /* check for VLAN, including QinQ */
7988         b0 = gen_linktype(cstate, ETHERTYPE_8021Q);
7989         b1 = gen_linktype(cstate, ETHERTYPE_8021AD);
7990         gen_or(b0,b1);
7991         b0 = b1;
7992         b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ);
7993         gen_or(b0,b1);
7994         b0 = b1;
7995 
7996         /* If a specific VLAN is requested, check VLAN id */
7997         if (vlan_num >= 0) {
7998                 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_H,
7999                               (bpf_int32)vlan_num, 0x0fff);
8000                 gen_and(b0, b1);
8001                 b0 = b1;
8002         }
8003 
8004 	/*
8005 	 * The payload follows the full header, including the
8006 	 * VLAN tags, so skip past this VLAN tag.
8007 	 */
8008         cstate->off_linkpl.constant_part += 4;
8009 
8010 	/*
8011 	 * The link-layer type information follows the VLAN tags, so
8012 	 * skip past this VLAN tag.
8013 	 */
8014         cstate->off_linktype.constant_part += 4;
8015 
8016         return b0;
8017 }
8018 
8019 /*
8020  * support IEEE 802.1Q VLAN trunk over ethernet
8021  */
8022 struct block *
gen_vlan(compiler_state_t * cstate,int vlan_num)8023 gen_vlan(compiler_state_t *cstate, int vlan_num)
8024 {
8025 	struct	block	*b0;
8026 
8027 	/* can't check for VLAN-encapsulated packets inside MPLS */
8028 	if (cstate->label_stack_depth > 0)
8029 		bpf_error(cstate, "no VLAN match after MPLS");
8030 
8031 	/*
8032 	 * Check for a VLAN packet, and then change the offsets to point
8033 	 * to the type and data fields within the VLAN packet.  Just
8034 	 * increment the offsets, so that we can support a hierarchy, e.g.
8035 	 * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
8036 	 * VLAN 100.
8037 	 *
8038 	 * XXX - this is a bit of a kludge.  If we were to split the
8039 	 * compiler into a parser that parses an expression and
8040 	 * generates an expression tree, and a code generator that
8041 	 * takes an expression tree (which could come from our
8042 	 * parser or from some other parser) and generates BPF code,
8043 	 * we could perhaps make the offsets parameters of routines
8044 	 * and, in the handler for an "AND" node, pass to subnodes
8045 	 * other than the VLAN node the adjusted offsets.
8046 	 *
8047 	 * This would mean that "vlan" would, instead of changing the
8048 	 * behavior of *all* tests after it, change only the behavior
8049 	 * of tests ANDed with it.  That would change the documented
8050 	 * semantics of "vlan", which might break some expressions.
8051 	 * However, it would mean that "(vlan and ip) or ip" would check
8052 	 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8053 	 * checking only for VLAN-encapsulated IP, so that could still
8054 	 * be considered worth doing; it wouldn't break expressions
8055 	 * that are of the form "vlan and ..." or "vlan N and ...",
8056 	 * which I suspect are the most common expressions involving
8057 	 * "vlan".  "vlan or ..." doesn't necessarily do what the user
8058 	 * would really want, now, as all the "or ..." tests would
8059 	 * be done assuming a VLAN, even though the "or" could be viewed
8060 	 * as meaning "or, if this isn't a VLAN packet...".
8061 	 */
8062 	switch (cstate->linktype) {
8063 
8064 	case DLT_EN10MB:
8065 	case DLT_NETANALYZER:
8066 	case DLT_NETANALYZER_TRANSPARENT:
8067 #if defined(SKF_AD_VLAN_TAG) && defined(SKF_AD_VLAN_TAG_PRESENT)
8068 		/* Verify that this is the outer part of the packet and
8069 		 * not encapsulated somehow. */
8070 		if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable &&
8071 		    cstate->off_linkhdr.constant_part ==
8072 		    cstate->off_outermostlinkhdr.constant_part) {
8073 			/*
8074 			 * Do we need special VLAN handling?
8075 			 */
8076 			if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
8077 				b0 = gen_vlan_bpf_extensions(cstate, vlan_num);
8078 			else
8079 				b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8080 		} else
8081 #endif
8082 			b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8083                 break;
8084 
8085 	case DLT_IEEE802_11:
8086 	case DLT_PRISM_HEADER:
8087 	case DLT_IEEE802_11_RADIO_AVS:
8088 	case DLT_IEEE802_11_RADIO:
8089 		b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8090 		break;
8091 
8092 	default:
8093 		bpf_error(cstate, "no VLAN support for data link type %d",
8094 		      cstate->linktype);
8095 		/*NOTREACHED*/
8096 	}
8097 
8098         cstate->vlan_stack_depth++;
8099 
8100 	return (b0);
8101 }
8102 
8103 /*
8104  * support for MPLS
8105  */
8106 struct block *
gen_mpls(compiler_state_t * cstate,int label_num)8107 gen_mpls(compiler_state_t *cstate, int label_num)
8108 {
8109 	struct	block	*b0, *b1;
8110 
8111         if (cstate->label_stack_depth > 0) {
8112             /* just match the bottom-of-stack bit clear */
8113             b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01);
8114         } else {
8115             /*
8116              * We're not in an MPLS stack yet, so check the link-layer
8117              * type against MPLS.
8118              */
8119             switch (cstate->linktype) {
8120 
8121             case DLT_C_HDLC: /* fall through */
8122             case DLT_EN10MB:
8123             case DLT_NETANALYZER:
8124             case DLT_NETANALYZER_TRANSPARENT:
8125                     b0 = gen_linktype(cstate, ETHERTYPE_MPLS);
8126                     break;
8127 
8128             case DLT_PPP:
8129                     b0 = gen_linktype(cstate, PPP_MPLS_UCAST);
8130                     break;
8131 
8132                     /* FIXME add other DLT_s ...
8133                      * for Frame-Relay/and ATM this may get messy due to SNAP headers
8134                      * leave it for now */
8135 
8136             default:
8137                     bpf_error(cstate, "no MPLS support for data link type %d",
8138                           cstate->linktype);
8139                     b0 = NULL;
8140                     /*NOTREACHED*/
8141                     break;
8142             }
8143         }
8144 
8145 	/* If a specific MPLS label is requested, check it */
8146 	if (label_num >= 0) {
8147 		label_num = label_num << 12; /* label is shifted 12 bits on the wire */
8148 		b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, (bpf_int32)label_num,
8149 		    0xfffff000); /* only compare the first 20 bits */
8150 		gen_and(b0, b1);
8151 		b0 = b1;
8152 	}
8153 
8154         /*
8155          * Change the offsets to point to the type and data fields within
8156          * the MPLS packet.  Just increment the offsets, so that we
8157          * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
8158          * capture packets with an outer label of 100000 and an inner
8159          * label of 1024.
8160          *
8161          * Increment the MPLS stack depth as well; this indicates that
8162          * we're checking MPLS-encapsulated headers, to make sure higher
8163          * level code generators don't try to match against IP-related
8164          * protocols such as Q_ARP, Q_RARP etc.
8165          *
8166          * XXX - this is a bit of a kludge.  See comments in gen_vlan().
8167          */
8168         cstate->off_nl_nosnap += 4;
8169         cstate->off_nl += 4;
8170         cstate->label_stack_depth++;
8171 	return (b0);
8172 }
8173 
8174 /*
8175  * Support PPPOE discovery and session.
8176  */
8177 struct block *
gen_pppoed(compiler_state_t * cstate)8178 gen_pppoed(compiler_state_t *cstate)
8179 {
8180 	/* check for PPPoE discovery */
8181 	return gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOED);
8182 }
8183 
8184 struct block *
gen_pppoes(compiler_state_t * cstate,int sess_num)8185 gen_pppoes(compiler_state_t *cstate, int sess_num)
8186 {
8187 	struct block *b0, *b1;
8188 
8189 	/*
8190 	 * Test against the PPPoE session link-layer type.
8191 	 */
8192 	b0 = gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOES);
8193 
8194 	/* If a specific session is requested, check PPPoE session id */
8195 	if (sess_num >= 0) {
8196 		b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W,
8197 		    (bpf_int32)sess_num, 0x0000ffff);
8198 		gen_and(b0, b1);
8199 		b0 = b1;
8200 	}
8201 
8202 	/*
8203 	 * Change the offsets to point to the type and data fields within
8204 	 * the PPP packet, and note that this is PPPoE rather than
8205 	 * raw PPP.
8206 	 *
8207 	 * XXX - this is a bit of a kludge.  If we were to split the
8208 	 * compiler into a parser that parses an expression and
8209 	 * generates an expression tree, and a code generator that
8210 	 * takes an expression tree (which could come from our
8211 	 * parser or from some other parser) and generates BPF code,
8212 	 * we could perhaps make the offsets parameters of routines
8213 	 * and, in the handler for an "AND" node, pass to subnodes
8214 	 * other than the PPPoE node the adjusted offsets.
8215 	 *
8216 	 * This would mean that "pppoes" would, instead of changing the
8217 	 * behavior of *all* tests after it, change only the behavior
8218 	 * of tests ANDed with it.  That would change the documented
8219 	 * semantics of "pppoes", which might break some expressions.
8220 	 * However, it would mean that "(pppoes and ip) or ip" would check
8221 	 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8222 	 * checking only for VLAN-encapsulated IP, so that could still
8223 	 * be considered worth doing; it wouldn't break expressions
8224 	 * that are of the form "pppoes and ..." which I suspect are the
8225 	 * most common expressions involving "pppoes".  "pppoes or ..."
8226 	 * doesn't necessarily do what the user would really want, now,
8227 	 * as all the "or ..." tests would be done assuming PPPoE, even
8228 	 * though the "or" could be viewed as meaning "or, if this isn't
8229 	 * a PPPoE packet...".
8230 	 *
8231 	 * The "network-layer" protocol is PPPoE, which has a 6-byte
8232 	 * PPPoE header, followed by a PPP packet.
8233 	 *
8234 	 * There is no HDLC encapsulation for the PPP packet (it's
8235 	 * encapsulated in PPPoES instead), so the link-layer type
8236 	 * starts at the first byte of the PPP packet.  For PPPoE,
8237 	 * that offset is relative to the beginning of the total
8238 	 * link-layer payload, including any 802.2 LLC header, so
8239 	 * it's 6 bytes past cstate->off_nl.
8240 	 */
8241 	PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable,
8242 	    cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */
8243 	    cstate->off_linkpl.reg);
8244 
8245 	cstate->off_linktype = cstate->off_linkhdr;
8246 	cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2;
8247 
8248 	cstate->off_nl = 0;
8249 	cstate->off_nl_nosnap = 0;	/* no 802.2 LLC */
8250 
8251 	return b0;
8252 }
8253 
8254 /* Check that this is Geneve and the VNI is correct if
8255  * specified. Parameterized to handle both IPv4 and IPv6. */
8256 static struct block *
gen_geneve_check(compiler_state_t * cstate,struct block * (* gen_portfn)(compiler_state_t *,int,int,int),enum e_offrel offrel,int vni)8257 gen_geneve_check(compiler_state_t *cstate,
8258     struct block *(*gen_portfn)(compiler_state_t *, int, int, int),
8259     enum e_offrel offrel, int vni)
8260 {
8261 	struct block *b0, *b1;
8262 
8263 	b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST);
8264 
8265 	/* Check that we are operating on version 0. Otherwise, we
8266 	 * can't decode the rest of the fields. The version is 2 bits
8267 	 * in the first byte of the Geneve header. */
8268 	b1 = gen_mcmp(cstate, offrel, 8, BPF_B, (bpf_int32)0, 0xc0);
8269 	gen_and(b0, b1);
8270 	b0 = b1;
8271 
8272 	if (vni >= 0) {
8273 		vni <<= 8; /* VNI is in the upper 3 bytes */
8274 		b1 = gen_mcmp(cstate, offrel, 12, BPF_W, (bpf_int32)vni,
8275 			      0xffffff00);
8276 		gen_and(b0, b1);
8277 		b0 = b1;
8278 	}
8279 
8280 	return b0;
8281 }
8282 
8283 /* The IPv4 and IPv6 Geneve checks need to do two things:
8284  * - Verify that this actually is Geneve with the right VNI.
8285  * - Place the IP header length (plus variable link prefix if
8286  *   needed) into register A to be used later to compute
8287  *   the inner packet offsets. */
8288 static struct block *
gen_geneve4(compiler_state_t * cstate,int vni)8289 gen_geneve4(compiler_state_t *cstate, int vni)
8290 {
8291 	struct block *b0, *b1;
8292 	struct slist *s, *s1;
8293 
8294 	b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni);
8295 
8296 	/* Load the IP header length into A. */
8297 	s = gen_loadx_iphdrlen(cstate);
8298 
8299 	s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8300 	sappend(s, s1);
8301 
8302 	/* Forcibly append these statements to the true condition
8303 	 * of the protocol check by creating a new block that is
8304 	 * always true and ANDing them. */
8305 	b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8306 	b1->stmts = s;
8307 	b1->s.k = 0;
8308 
8309 	gen_and(b0, b1);
8310 
8311 	return b1;
8312 }
8313 
8314 static struct block *
gen_geneve6(compiler_state_t * cstate,int vni)8315 gen_geneve6(compiler_state_t *cstate, int vni)
8316 {
8317 	struct block *b0, *b1;
8318 	struct slist *s, *s1;
8319 
8320 	b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni);
8321 
8322 	/* Load the IP header length. We need to account for a
8323 	 * variable length link prefix if there is one. */
8324 	s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
8325 	if (s) {
8326 		s1 = new_stmt(cstate, BPF_LD|BPF_IMM);
8327 		s1->s.k = 40;
8328 		sappend(s, s1);
8329 
8330 		s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8331 		s1->s.k = 0;
8332 		sappend(s, s1);
8333 	} else {
8334 		s = new_stmt(cstate, BPF_LD|BPF_IMM);
8335 		s->s.k = 40;
8336 	}
8337 
8338 	/* Forcibly append these statements to the true condition
8339 	 * of the protocol check by creating a new block that is
8340 	 * always true and ANDing them. */
8341 	s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8342 	sappend(s, s1);
8343 
8344 	b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8345 	b1->stmts = s;
8346 	b1->s.k = 0;
8347 
8348 	gen_and(b0, b1);
8349 
8350 	return b1;
8351 }
8352 
8353 /* We need to store three values based on the Geneve header::
8354  * - The offset of the linktype.
8355  * - The offset of the end of the Geneve header.
8356  * - The offset of the end of the encapsulated MAC header. */
8357 static struct slist *
gen_geneve_offsets(compiler_state_t * cstate)8358 gen_geneve_offsets(compiler_state_t *cstate)
8359 {
8360 	struct slist *s, *s1, *s_proto;
8361 
8362 	/* First we need to calculate the offset of the Geneve header
8363 	 * itself. This is composed of the IP header previously calculated
8364 	 * (include any variable link prefix) and stored in A plus the
8365 	 * fixed sized headers (fixed link prefix, MAC length, and UDP
8366 	 * header). */
8367 	s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8368 	s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8;
8369 
8370 	/* Stash this in X since we'll need it later. */
8371 	s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8372 	sappend(s, s1);
8373 
8374 	/* The EtherType in Geneve is 2 bytes in. Calculate this and
8375 	 * store it. */
8376 	s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8377 	s1->s.k = 2;
8378 	sappend(s, s1);
8379 
8380 	cstate->off_linktype.reg = alloc_reg(cstate);
8381 	cstate->off_linktype.is_variable = 1;
8382 	cstate->off_linktype.constant_part = 0;
8383 
8384 	s1 = new_stmt(cstate, BPF_ST);
8385 	s1->s.k = cstate->off_linktype.reg;
8386 	sappend(s, s1);
8387 
8388 	/* Load the Geneve option length and mask and shift to get the
8389 	 * number of bytes. It is stored in the first byte of the Geneve
8390 	 * header. */
8391 	s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
8392 	s1->s.k = 0;
8393 	sappend(s, s1);
8394 
8395 	s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
8396 	s1->s.k = 0x3f;
8397 	sappend(s, s1);
8398 
8399 	s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
8400 	s1->s.k = 4;
8401 	sappend(s, s1);
8402 
8403 	/* Add in the rest of the Geneve base header. */
8404 	s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8405 	s1->s.k = 8;
8406 	sappend(s, s1);
8407 
8408 	/* Add the Geneve header length to its offset and store. */
8409 	s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8410 	s1->s.k = 0;
8411 	sappend(s, s1);
8412 
8413 	/* Set the encapsulated type as Ethernet. Even though we may
8414 	 * not actually have Ethernet inside there are two reasons this
8415 	 * is useful:
8416 	 * - The linktype field is always in EtherType format regardless
8417 	 *   of whether it is in Geneve or an inner Ethernet frame.
8418 	 * - The only link layer that we have specific support for is
8419 	 *   Ethernet. We will confirm that the packet actually is
8420 	 *   Ethernet at runtime before executing these checks. */
8421 	PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate));
8422 
8423 	s1 = new_stmt(cstate, BPF_ST);
8424 	s1->s.k = cstate->off_linkhdr.reg;
8425 	sappend(s, s1);
8426 
8427 	/* Calculate whether we have an Ethernet header or just raw IP/
8428 	 * MPLS/etc. If we have Ethernet, advance the end of the MAC offset
8429 	 * and linktype by 14 bytes so that the network header can be found
8430 	 * seamlessly. Otherwise, keep what we've calculated already. */
8431 
8432 	/* We have a bare jmp so we can't use the optimizer. */
8433 	cstate->no_optimize = 1;
8434 
8435 	/* Load the EtherType in the Geneve header, 2 bytes in. */
8436 	s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H);
8437 	s1->s.k = 2;
8438 	sappend(s, s1);
8439 
8440 	/* Load X with the end of the Geneve header. */
8441 	s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8442 	s1->s.k = cstate->off_linkhdr.reg;
8443 	sappend(s, s1);
8444 
8445 	/* Check if the EtherType is Transparent Ethernet Bridging. At the
8446 	 * end of this check, we should have the total length in X. In
8447 	 * the non-Ethernet case, it's already there. */
8448 	s_proto = new_stmt(cstate, JMP(BPF_JEQ));
8449 	s_proto->s.k = ETHERTYPE_TEB;
8450 	sappend(s, s_proto);
8451 
8452 	s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8453 	sappend(s, s1);
8454 	s_proto->s.jt = s1;
8455 
8456 	/* Since this is Ethernet, use the EtherType of the payload
8457 	 * directly as the linktype. Overwrite what we already have. */
8458 	s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8459 	s1->s.k = 12;
8460 	sappend(s, s1);
8461 
8462 	s1 = new_stmt(cstate, BPF_ST);
8463 	s1->s.k = cstate->off_linktype.reg;
8464 	sappend(s, s1);
8465 
8466 	/* Advance two bytes further to get the end of the Ethernet
8467 	 * header. */
8468 	s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8469 	s1->s.k = 2;
8470 	sappend(s, s1);
8471 
8472 	/* Move the result to X. */
8473 	s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8474 	sappend(s, s1);
8475 
8476 	/* Store the final result of our linkpl calculation. */
8477 	cstate->off_linkpl.reg = alloc_reg(cstate);
8478 	cstate->off_linkpl.is_variable = 1;
8479 	cstate->off_linkpl.constant_part = 0;
8480 
8481 	s1 = new_stmt(cstate, BPF_STX);
8482 	s1->s.k = cstate->off_linkpl.reg;
8483 	sappend(s, s1);
8484 	s_proto->s.jf = s1;
8485 
8486 	cstate->off_nl = 0;
8487 
8488 	return s;
8489 }
8490 
8491 /* Check to see if this is a Geneve packet. */
8492 struct block *
gen_geneve(compiler_state_t * cstate,int vni)8493 gen_geneve(compiler_state_t *cstate, int vni)
8494 {
8495 	struct block *b0, *b1;
8496 	struct slist *s;
8497 
8498 	b0 = gen_geneve4(cstate, vni);
8499 	b1 = gen_geneve6(cstate, vni);
8500 
8501 	gen_or(b0, b1);
8502 	b0 = b1;
8503 
8504 	/* Later filters should act on the payload of the Geneve frame,
8505 	 * update all of the header pointers. Attach this code so that
8506 	 * it gets executed in the event that the Geneve filter matches. */
8507 	s = gen_geneve_offsets(cstate);
8508 
8509 	b1 = gen_true(cstate);
8510 	sappend(s, b1->stmts);
8511 	b1->stmts = s;
8512 
8513 	gen_and(b0, b1);
8514 
8515 	cstate->is_geneve = 1;
8516 
8517 	return b1;
8518 }
8519 
8520 /* Check that the encapsulated frame has a link layer header
8521  * for Ethernet filters. */
8522 static struct block *
gen_geneve_ll_check(compiler_state_t * cstate)8523 gen_geneve_ll_check(compiler_state_t *cstate)
8524 {
8525 	struct block *b0;
8526 	struct slist *s, *s1;
8527 
8528 	/* The easiest way to see if there is a link layer present
8529 	 * is to check if the link layer header and payload are not
8530 	 * the same. */
8531 
8532 	/* Geneve always generates pure variable offsets so we can
8533 	 * compare only the registers. */
8534 	s = new_stmt(cstate, BPF_LD|BPF_MEM);
8535 	s->s.k = cstate->off_linkhdr.reg;
8536 
8537 	s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8538 	s1->s.k = cstate->off_linkpl.reg;
8539 	sappend(s, s1);
8540 
8541 	b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8542 	b0->stmts = s;
8543 	b0->s.k = 0;
8544 	gen_not(b0);
8545 
8546 	return b0;
8547 }
8548 
8549 struct block *
gen_atmfield_code(compiler_state_t * cstate,int atmfield,bpf_int32 jvalue,bpf_u_int32 jtype,int reverse)8550 gen_atmfield_code(compiler_state_t *cstate, int atmfield, bpf_int32 jvalue,
8551     bpf_u_int32 jtype, int reverse)
8552 {
8553 	struct block *b0;
8554 
8555 	switch (atmfield) {
8556 
8557 	case A_VPI:
8558 		if (!cstate->is_atm)
8559 			bpf_error(cstate, "'vpi' supported only on raw ATM");
8560 		if (cstate->off_vpi == (u_int)-1)
8561 			abort();
8562 		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffff, jtype,
8563 		    reverse, jvalue);
8564 		break;
8565 
8566 	case A_VCI:
8567 		if (!cstate->is_atm)
8568 			bpf_error(cstate, "'vci' supported only on raw ATM");
8569 		if (cstate->off_vci == (u_int)-1)
8570 			abort();
8571 		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffff, jtype,
8572 		    reverse, jvalue);
8573 		break;
8574 
8575 	case A_PROTOTYPE:
8576 		if (cstate->off_proto == (u_int)-1)
8577 			abort();	/* XXX - this isn't on FreeBSD */
8578 		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0f, jtype,
8579 		    reverse, jvalue);
8580 		break;
8581 
8582 	case A_MSGTYPE:
8583 		if (cstate->off_payload == (u_int)-1)
8584 			abort();
8585 		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
8586 		    0xffffffff, jtype, reverse, jvalue);
8587 		break;
8588 
8589 	case A_CALLREFTYPE:
8590 		if (!cstate->is_atm)
8591 			bpf_error(cstate, "'callref' supported only on raw ATM");
8592 		if (cstate->off_proto == (u_int)-1)
8593 			abort();
8594 		b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffff,
8595 		    jtype, reverse, jvalue);
8596 		break;
8597 
8598 	default:
8599 		abort();
8600 	}
8601 	return b0;
8602 }
8603 
8604 struct block *
gen_atmtype_abbrev(compiler_state_t * cstate,int type)8605 gen_atmtype_abbrev(compiler_state_t *cstate, int type)
8606 {
8607 	struct block *b0, *b1;
8608 
8609 	switch (type) {
8610 
8611 	case A_METAC:
8612 		/* Get all packets in Meta signalling Circuit */
8613 		if (!cstate->is_atm)
8614 			bpf_error(cstate, "'metac' supported only on raw ATM");
8615 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8616 		b1 = gen_atmfield_code(cstate, A_VCI, 1, BPF_JEQ, 0);
8617 		gen_and(b0, b1);
8618 		break;
8619 
8620 	case A_BCC:
8621 		/* Get all packets in Broadcast Circuit*/
8622 		if (!cstate->is_atm)
8623 			bpf_error(cstate, "'bcc' supported only on raw ATM");
8624 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8625 		b1 = gen_atmfield_code(cstate, A_VCI, 2, BPF_JEQ, 0);
8626 		gen_and(b0, b1);
8627 		break;
8628 
8629 	case A_OAMF4SC:
8630 		/* Get all cells in Segment OAM F4 circuit*/
8631 		if (!cstate->is_atm)
8632 			bpf_error(cstate, "'oam4sc' supported only on raw ATM");
8633 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8634 		b1 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
8635 		gen_and(b0, b1);
8636 		break;
8637 
8638 	case A_OAMF4EC:
8639 		/* Get all cells in End-to-End OAM F4 Circuit*/
8640 		if (!cstate->is_atm)
8641 			bpf_error(cstate, "'oam4ec' supported only on raw ATM");
8642 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8643 		b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
8644 		gen_and(b0, b1);
8645 		break;
8646 
8647 	case A_SC:
8648 		/*  Get all packets in connection Signalling Circuit */
8649 		if (!cstate->is_atm)
8650 			bpf_error(cstate, "'sc' supported only on raw ATM");
8651 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8652 		b1 = gen_atmfield_code(cstate, A_VCI, 5, BPF_JEQ, 0);
8653 		gen_and(b0, b1);
8654 		break;
8655 
8656 	case A_ILMIC:
8657 		/* Get all packets in ILMI Circuit */
8658 		if (!cstate->is_atm)
8659 			bpf_error(cstate, "'ilmic' supported only on raw ATM");
8660 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8661 		b1 = gen_atmfield_code(cstate, A_VCI, 16, BPF_JEQ, 0);
8662 		gen_and(b0, b1);
8663 		break;
8664 
8665 	case A_LANE:
8666 		/* Get all LANE packets */
8667 		if (!cstate->is_atm)
8668 			bpf_error(cstate, "'lane' supported only on raw ATM");
8669 		b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
8670 
8671 		/*
8672 		 * Arrange that all subsequent tests assume LANE
8673 		 * rather than LLC-encapsulated packets, and set
8674 		 * the offsets appropriately for LANE-encapsulated
8675 		 * Ethernet.
8676 		 *
8677 		 * We assume LANE means Ethernet, not Token Ring.
8678 		 */
8679 		PUSH_LINKHDR(cstate, DLT_EN10MB, 0,
8680 		    cstate->off_payload + 2,	/* Ethernet header */
8681 		    -1);
8682 		cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
8683 		cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14;	/* Ethernet */
8684 		cstate->off_nl = 0;			/* Ethernet II */
8685 		cstate->off_nl_nosnap = 3;		/* 802.3+802.2 */
8686 		break;
8687 
8688 	case A_LLC:
8689 		/* Get all LLC-encapsulated packets */
8690 		if (!cstate->is_atm)
8691 			bpf_error(cstate, "'llc' supported only on raw ATM");
8692 		b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
8693 		cstate->linktype = cstate->prevlinktype;
8694 		break;
8695 
8696 	default:
8697 		abort();
8698 	}
8699 	return b1;
8700 }
8701 
8702 /*
8703  * Filtering for MTP2 messages based on li value
8704  * FISU, length is null
8705  * LSSU, length is 1 or 2
8706  * MSU, length is 3 or more
8707  * For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits
8708  */
8709 struct block *
gen_mtp2type_abbrev(compiler_state_t * cstate,int type)8710 gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
8711 {
8712 	struct block *b0, *b1;
8713 
8714 	switch (type) {
8715 
8716 	case M_FISU:
8717 		if ( (cstate->linktype != DLT_MTP2) &&
8718 		     (cstate->linktype != DLT_ERF) &&
8719 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8720 			bpf_error(cstate, "'fisu' supported only on MTP2");
8721 		/* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
8722 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
8723 		break;
8724 
8725 	case M_LSSU:
8726 		if ( (cstate->linktype != DLT_MTP2) &&
8727 		     (cstate->linktype != DLT_ERF) &&
8728 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8729 			bpf_error(cstate, "'lssu' supported only on MTP2");
8730 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
8731 		b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
8732 		gen_and(b1, b0);
8733 		break;
8734 
8735 	case M_MSU:
8736 		if ( (cstate->linktype != DLT_MTP2) &&
8737 		     (cstate->linktype != DLT_ERF) &&
8738 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8739 			bpf_error(cstate, "'msu' supported only on MTP2");
8740 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
8741 		break;
8742 
8743 	case MH_FISU:
8744 		if ( (cstate->linktype != DLT_MTP2) &&
8745 		     (cstate->linktype != DLT_ERF) &&
8746 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8747 			bpf_error(cstate, "'hfisu' supported only on MTP2_HSL");
8748 		/* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
8749 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JEQ, 0, 0);
8750 		break;
8751 
8752 	case MH_LSSU:
8753 		if ( (cstate->linktype != DLT_MTP2) &&
8754 		     (cstate->linktype != DLT_ERF) &&
8755 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8756 			bpf_error(cstate, "'hlssu' supported only on MTP2_HSL");
8757 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 1, 0x0100);
8758 		b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0);
8759 		gen_and(b1, b0);
8760 		break;
8761 
8762 	case MH_MSU:
8763 		if ( (cstate->linktype != DLT_MTP2) &&
8764 		     (cstate->linktype != DLT_ERF) &&
8765 		     (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8766 			bpf_error(cstate, "'hmsu' supported only on MTP2_HSL");
8767 		b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0x0100);
8768 		break;
8769 
8770 	default:
8771 		abort();
8772 	}
8773 	return b0;
8774 }
8775 
8776 struct block *
gen_mtp3field_code(compiler_state_t * cstate,int mtp3field,bpf_u_int32 jvalue,bpf_u_int32 jtype,int reverse)8777 gen_mtp3field_code(compiler_state_t *cstate, int mtp3field, bpf_u_int32 jvalue,
8778     bpf_u_int32 jtype, int reverse)
8779 {
8780 	struct block *b0;
8781 	bpf_u_int32 val1 , val2 , val3;
8782 	u_int newoff_sio = cstate->off_sio;
8783 	u_int newoff_opc = cstate->off_opc;
8784 	u_int newoff_dpc = cstate->off_dpc;
8785 	u_int newoff_sls = cstate->off_sls;
8786 
8787 	switch (mtp3field) {
8788 
8789 	case MH_SIO:
8790 		newoff_sio += 3; /* offset for MTP2_HSL */
8791 		/* FALLTHROUGH */
8792 
8793 	case M_SIO:
8794 		if (cstate->off_sio == (u_int)-1)
8795 			bpf_error(cstate, "'sio' supported only on SS7");
8796 		/* sio coded on 1 byte so max value 255 */
8797 		if(jvalue > 255)
8798 		        bpf_error(cstate, "sio value %u too big; max value = 255",
8799 		            jvalue);
8800 		b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffff,
8801 		    (u_int)jtype, reverse, (u_int)jvalue);
8802 		break;
8803 
8804 	case MH_OPC:
8805 		newoff_opc+=3;
8806         case M_OPC:
8807 	        if (cstate->off_opc == (u_int)-1)
8808 			bpf_error(cstate, "'opc' supported only on SS7");
8809 		/* opc coded on 14 bits so max value 16383 */
8810 		if (jvalue > 16383)
8811 		        bpf_error(cstate, "opc value %u too big; max value = 16383",
8812 		            jvalue);
8813 		/* the following instructions are made to convert jvalue
8814 		 * to the form used to write opc in an ss7 message*/
8815 		val1 = jvalue & 0x00003c00;
8816 		val1 = val1 >>10;
8817 		val2 = jvalue & 0x000003fc;
8818 		val2 = val2 <<6;
8819 		val3 = jvalue & 0x00000003;
8820 		val3 = val3 <<22;
8821 		jvalue = val1 + val2 + val3;
8822 		b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0f,
8823 		    (u_int)jtype, reverse, (u_int)jvalue);
8824 		break;
8825 
8826 	case MH_DPC:
8827 		newoff_dpc += 3;
8828 		/* FALLTHROUGH */
8829 
8830 	case M_DPC:
8831 	        if (cstate->off_dpc == (u_int)-1)
8832 			bpf_error(cstate, "'dpc' supported only on SS7");
8833 		/* dpc coded on 14 bits so max value 16383 */
8834 		if (jvalue > 16383)
8835 		        bpf_error(cstate, "dpc value %u too big; max value = 16383",
8836 		            jvalue);
8837 		/* the following instructions are made to convert jvalue
8838 		 * to the forme used to write dpc in an ss7 message*/
8839 		val1 = jvalue & 0x000000ff;
8840 		val1 = val1 << 24;
8841 		val2 = jvalue & 0x00003f00;
8842 		val2 = val2 << 8;
8843 		jvalue = val1 + val2;
8844 		b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000,
8845 		    (u_int)jtype, reverse, (u_int)jvalue);
8846 		break;
8847 
8848 	case MH_SLS:
8849 	  newoff_sls+=3;
8850 	case M_SLS:
8851 	        if (cstate->off_sls == (u_int)-1)
8852 			bpf_error(cstate, "'sls' supported only on SS7");
8853 		/* sls coded on 4 bits so max value 15 */
8854 		if (jvalue > 15)
8855 		         bpf_error(cstate, "sls value %u too big; max value = 15",
8856 		             jvalue);
8857 		/* the following instruction is made to convert jvalue
8858 		 * to the forme used to write sls in an ss7 message*/
8859 		jvalue = jvalue << 4;
8860 		b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0,
8861 		    (u_int)jtype,reverse, (u_int)jvalue);
8862 		break;
8863 
8864 	default:
8865 		abort();
8866 	}
8867 	return b0;
8868 }
8869 
8870 static struct block *
gen_msg_abbrev(compiler_state_t * cstate,int type)8871 gen_msg_abbrev(compiler_state_t *cstate, int type)
8872 {
8873 	struct block *b1;
8874 
8875 	/*
8876 	 * Q.2931 signalling protocol messages for handling virtual circuits
8877 	 * establishment and teardown
8878 	 */
8879 	switch (type) {
8880 
8881 	case A_SETUP:
8882 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
8883 		break;
8884 
8885 	case A_CALLPROCEED:
8886 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
8887 		break;
8888 
8889 	case A_CONNECT:
8890 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
8891 		break;
8892 
8893 	case A_CONNECTACK:
8894 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
8895 		break;
8896 
8897 	case A_RELEASE:
8898 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
8899 		break;
8900 
8901 	case A_RELEASE_DONE:
8902 		b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
8903 		break;
8904 
8905 	default:
8906 		abort();
8907 	}
8908 	return b1;
8909 }
8910 
8911 struct block *
gen_atmmulti_abbrev(compiler_state_t * cstate,int type)8912 gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
8913 {
8914 	struct block *b0, *b1;
8915 
8916 	switch (type) {
8917 
8918 	case A_OAM:
8919 		if (!cstate->is_atm)
8920 			bpf_error(cstate, "'oam' supported only on raw ATM");
8921 		b1 = gen_atmmulti_abbrev(cstate, A_OAMF4);
8922 		break;
8923 
8924 	case A_OAMF4:
8925 		if (!cstate->is_atm)
8926 			bpf_error(cstate, "'oamf4' supported only on raw ATM");
8927 		/* OAM F4 type */
8928 		b0 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
8929 		b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
8930 		gen_or(b0, b1);
8931 		b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8932 		gen_and(b0, b1);
8933 		break;
8934 
8935 	case A_CONNECTMSG:
8936 		/*
8937 		 * Get Q.2931 signalling messages for switched
8938 		 * virtual connection
8939 		 */
8940 		if (!cstate->is_atm)
8941 			bpf_error(cstate, "'connectmsg' supported only on raw ATM");
8942 		b0 = gen_msg_abbrev(cstate, A_SETUP);
8943 		b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
8944 		gen_or(b0, b1);
8945 		b0 = gen_msg_abbrev(cstate, A_CONNECT);
8946 		gen_or(b0, b1);
8947 		b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
8948 		gen_or(b0, b1);
8949 		b0 = gen_msg_abbrev(cstate, A_RELEASE);
8950 		gen_or(b0, b1);
8951 		b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
8952 		gen_or(b0, b1);
8953 		b0 = gen_atmtype_abbrev(cstate, A_SC);
8954 		gen_and(b0, b1);
8955 		break;
8956 
8957 	case A_METACONNECT:
8958 		if (!cstate->is_atm)
8959 			bpf_error(cstate, "'metaconnect' supported only on raw ATM");
8960 		b0 = gen_msg_abbrev(cstate, A_SETUP);
8961 		b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
8962 		gen_or(b0, b1);
8963 		b0 = gen_msg_abbrev(cstate, A_CONNECT);
8964 		gen_or(b0, b1);
8965 		b0 = gen_msg_abbrev(cstate, A_RELEASE);
8966 		gen_or(b0, b1);
8967 		b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
8968 		gen_or(b0, b1);
8969 		b0 = gen_atmtype_abbrev(cstate, A_METAC);
8970 		gen_and(b0, b1);
8971 		break;
8972 
8973 	default:
8974 		abort();
8975 	}
8976 	return b1;
8977 }
8978