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 #include <pcap-types.h>
28 #ifdef _WIN32
29 #include <ws2tcpip.h>
30 #else
31 #include <sys/socket.h>
32
33 #ifdef __NetBSD__
34 #include <sys/param.h>
35 #endif
36
37 #include <netinet/in.h>
38 #include <arpa/inet.h>
39 #endif /* _WIN32 */
40
41 #include <stdlib.h>
42 #include <string.h>
43 #include <memory.h>
44 #include <setjmp.h>
45 #include <stdarg.h>
46
47 #ifdef MSDOS
48 #include "pcap-dos.h"
49 #endif
50
51 #include "pcap-int.h"
52
53 #include "ethertype.h"
54 #include "nlpid.h"
55 #include "llc.h"
56 #include "gencode.h"
57 #include "ieee80211.h"
58 #include "atmuni31.h"
59 #include "sunatmpos.h"
60 #include "ppp.h"
61 #include "pcap/sll.h"
62 #include "pcap/ipnet.h"
63 #include "arcnet.h"
64
65 #include "grammar.h"
66 #include "scanner.h"
67
68 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
69 #include <linux/types.h>
70 #include <linux/if_packet.h>
71 #include <linux/filter.h>
72 #endif
73
74 #ifdef HAVE_NET_PFVAR_H
75 #include <sys/socket.h>
76 #include <net/if.h>
77 #include <net/pfvar.h>
78 #include <net/if_pflog.h>
79 #endif
80
81 #ifndef offsetof
82 #define offsetof(s, e) ((size_t)&((s *)0)->e)
83 #endif
84
85 #ifdef _WIN32
86 #ifdef INET6
87 #if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
88 /* IPv6 address */
89 struct in6_addr
90 {
91 union
92 {
93 uint8_t u6_addr8[16];
94 uint16_t u6_addr16[8];
95 uint32_t u6_addr32[4];
96 } in6_u;
97 #define s6_addr in6_u.u6_addr8
98 #define s6_addr16 in6_u.u6_addr16
99 #define s6_addr32 in6_u.u6_addr32
100 #define s6_addr64 in6_u.u6_addr64
101 };
102
103 typedef unsigned short sa_family_t;
104
105 #define __SOCKADDR_COMMON(sa_prefix) \
106 sa_family_t sa_prefix##family
107
108 /* Ditto, for IPv6. */
109 struct sockaddr_in6
110 {
111 __SOCKADDR_COMMON (sin6_);
112 uint16_t sin6_port; /* Transport layer port # */
113 uint32_t sin6_flowinfo; /* IPv6 flow information */
114 struct in6_addr sin6_addr; /* IPv6 address */
115 };
116
117 #ifndef EAI_ADDRFAMILY
118 struct addrinfo {
119 int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
120 int ai_family; /* PF_xxx */
121 int ai_socktype; /* SOCK_xxx */
122 int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
123 size_t ai_addrlen; /* length of ai_addr */
124 char *ai_canonname; /* canonical name for hostname */
125 struct sockaddr *ai_addr; /* binary address */
126 struct addrinfo *ai_next; /* next structure in linked list */
127 };
128 #endif /* EAI_ADDRFAMILY */
129 #endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
130 #endif /* INET6 */
131 #else /* _WIN32 */
132 #include <netdb.h> /* for "struct addrinfo" */
133 #endif /* _WIN32 */
134 #include <pcap/namedb.h>
135
136 #include "nametoaddr.h"
137
138 #define ETHERMTU 1500
139
140 #ifndef ETHERTYPE_TEB
141 #define ETHERTYPE_TEB 0x6558
142 #endif
143
144 #ifndef IPPROTO_HOPOPTS
145 #define IPPROTO_HOPOPTS 0
146 #endif
147 #ifndef IPPROTO_ROUTING
148 #define IPPROTO_ROUTING 43
149 #endif
150 #ifndef IPPROTO_FRAGMENT
151 #define IPPROTO_FRAGMENT 44
152 #endif
153 #ifndef IPPROTO_DSTOPTS
154 #define IPPROTO_DSTOPTS 60
155 #endif
156 #ifndef IPPROTO_SCTP
157 #define IPPROTO_SCTP 132
158 #endif
159
160 #define GENEVE_PORT 6081
161
162 #ifdef HAVE_OS_PROTO_H
163 #include "os-proto.h"
164 #endif
165
166 #define JMP(c) ((c)|BPF_JMP|BPF_K)
167
168 /*
169 * "Push" the current value of the link-layer header type and link-layer
170 * header offset onto a "stack", and set a new value. (It's not a
171 * full-blown stack; we keep only the top two items.)
172 */
173 #define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
174 { \
175 (cs)->prevlinktype = (cs)->linktype; \
176 (cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
177 (cs)->linktype = (new_linktype); \
178 (cs)->off_linkhdr.is_variable = (new_is_variable); \
179 (cs)->off_linkhdr.constant_part = (new_constant_part); \
180 (cs)->off_linkhdr.reg = (new_reg); \
181 (cs)->is_geneve = 0; \
182 }
183
184 /*
185 * Offset "not set" value.
186 */
187 #define OFFSET_NOT_SET 0xffffffffU
188
189 /*
190 * Absolute offsets, which are offsets from the beginning of the raw
191 * packet data, are, in the general case, the sum of a variable value
192 * and a constant value; the variable value may be absent, in which
193 * case the offset is only the constant value, and the constant value
194 * may be zero, in which case the offset is only the variable value.
195 *
196 * bpf_abs_offset is a structure containing all that information:
197 *
198 * is_variable is 1 if there's a variable part.
199 *
200 * constant_part is the constant part of the value, possibly zero;
201 *
202 * if is_variable is 1, reg is the register number for a register
203 * containing the variable value if the register has been assigned,
204 * and -1 otherwise.
205 */
206 typedef struct {
207 int is_variable;
208 u_int constant_part;
209 int reg;
210 } bpf_abs_offset;
211
212 /*
213 * Value passed to gen_load_a() to indicate what the offset argument
214 * is relative to the beginning of.
215 */
216 enum e_offrel {
217 OR_PACKET, /* full packet data */
218 OR_LINKHDR, /* link-layer header */
219 OR_PREVLINKHDR, /* previous link-layer header */
220 OR_LLC, /* 802.2 LLC header */
221 OR_PREVMPLSHDR, /* previous MPLS header */
222 OR_LINKTYPE, /* link-layer type */
223 OR_LINKPL, /* link-layer payload */
224 OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */
225 OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */
226 OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */
227 };
228
229 /*
230 * We divy out chunks of memory rather than call malloc each time so
231 * we don't have to worry about leaking memory. It's probably
232 * not a big deal if all this memory was wasted but if this ever
233 * goes into a library that would probably not be a good idea.
234 *
235 * XXX - this *is* in a library....
236 */
237 #define NCHUNKS 16
238 #define CHUNK0SIZE 1024
239 struct chunk {
240 size_t n_left;
241 void *m;
242 };
243
244 /* Code generator state */
245
246 struct _compiler_state {
247 jmp_buf top_ctx;
248 pcap_t *bpf_pcap;
249
250 struct icode ic;
251
252 int snaplen;
253
254 int linktype;
255 int prevlinktype;
256 int outermostlinktype;
257
258 bpf_u_int32 netmask;
259 int no_optimize;
260
261 /* Hack for handling VLAN and MPLS stacks. */
262 u_int label_stack_depth;
263 u_int vlan_stack_depth;
264
265 /* XXX */
266 u_int pcap_fddipad;
267
268 /*
269 * As errors are handled by a longjmp, anything allocated must
270 * be freed in the longjmp handler, so it must be reachable
271 * from that handler.
272 *
273 * One thing that's allocated is the result of pcap_nametoaddrinfo();
274 * it must be freed with freeaddrinfo(). This variable points to
275 * any addrinfo structure that would need to be freed.
276 */
277 struct addrinfo *ai;
278
279 /*
280 * Various code constructs need to know the layout of the packet.
281 * These values give the necessary offsets from the beginning
282 * of the packet data.
283 */
284
285 /*
286 * Absolute offset of the beginning of the link-layer header.
287 */
288 bpf_abs_offset off_linkhdr;
289
290 /*
291 * If we're checking a link-layer header for a packet encapsulated
292 * in another protocol layer, this is the equivalent information
293 * for the previous layers' link-layer header from the beginning
294 * of the raw packet data.
295 */
296 bpf_abs_offset off_prevlinkhdr;
297
298 /*
299 * This is the equivalent information for the outermost layers'
300 * link-layer header.
301 */
302 bpf_abs_offset off_outermostlinkhdr;
303
304 /*
305 * Absolute offset of the beginning of the link-layer payload.
306 */
307 bpf_abs_offset off_linkpl;
308
309 /*
310 * "off_linktype" is the offset to information in the link-layer
311 * header giving the packet type. This is an absolute offset
312 * from the beginning of the packet.
313 *
314 * For Ethernet, it's the offset of the Ethernet type field; this
315 * means that it must have a value that skips VLAN tags.
316 *
317 * For link-layer types that always use 802.2 headers, it's the
318 * offset of the LLC header; this means that it must have a value
319 * that skips VLAN tags.
320 *
321 * For PPP, it's the offset of the PPP type field.
322 *
323 * For Cisco HDLC, it's the offset of the CHDLC type field.
324 *
325 * For BSD loopback, it's the offset of the AF_ value.
326 *
327 * For Linux cooked sockets, it's the offset of the type field.
328 *
329 * off_linktype.constant_part is set to OFFSET_NOT_SET for no
330 * encapsulation, in which case, IP is assumed.
331 */
332 bpf_abs_offset off_linktype;
333
334 /*
335 * TRUE if the link layer includes an ATM pseudo-header.
336 */
337 int is_atm;
338
339 /*
340 * TRUE if "geneve" appeared in the filter; it causes us to
341 * generate code that checks for a Geneve header and assume
342 * that later filters apply to the encapsulated payload.
343 */
344 int is_geneve;
345
346 /*
347 * TRUE if we need variable length part of VLAN offset
348 */
349 int is_vlan_vloffset;
350
351 /*
352 * These are offsets for the ATM pseudo-header.
353 */
354 u_int off_vpi;
355 u_int off_vci;
356 u_int off_proto;
357
358 /*
359 * These are offsets for the MTP2 fields.
360 */
361 u_int off_li;
362 u_int off_li_hsl;
363
364 /*
365 * These are offsets for the MTP3 fields.
366 */
367 u_int off_sio;
368 u_int off_opc;
369 u_int off_dpc;
370 u_int off_sls;
371
372 /*
373 * This is the offset of the first byte after the ATM pseudo_header,
374 * or -1 if there is no ATM pseudo-header.
375 */
376 u_int off_payload;
377
378 /*
379 * These are offsets to the beginning of the network-layer header.
380 * They are relative to the beginning of the link-layer payload
381 * (i.e., they don't include off_linkhdr.constant_part or
382 * off_linkpl.constant_part).
383 *
384 * If the link layer never uses 802.2 LLC:
385 *
386 * "off_nl" and "off_nl_nosnap" are the same.
387 *
388 * If the link layer always uses 802.2 LLC:
389 *
390 * "off_nl" is the offset if there's a SNAP header following
391 * the 802.2 header;
392 *
393 * "off_nl_nosnap" is the offset if there's no SNAP header.
394 *
395 * If the link layer is Ethernet:
396 *
397 * "off_nl" is the offset if the packet is an Ethernet II packet
398 * (we assume no 802.3+802.2+SNAP);
399 *
400 * "off_nl_nosnap" is the offset if the packet is an 802.3 packet
401 * with an 802.2 header following it.
402 */
403 u_int off_nl;
404 u_int off_nl_nosnap;
405
406 /*
407 * Here we handle simple allocation of the scratch registers.
408 * If too many registers are alloc'd, the allocator punts.
409 */
410 int regused[BPF_MEMWORDS];
411 int curreg;
412
413 /*
414 * Memory chunks.
415 */
416 struct chunk chunks[NCHUNKS];
417 int cur_chunk;
418 };
419
420 void PCAP_NORETURN
bpf_syntax_error(compiler_state_t * cstate,const char * msg)421 bpf_syntax_error(compiler_state_t *cstate, const char *msg)
422 {
423 bpf_error(cstate, "syntax error in filter expression: %s", msg);
424 /* NOTREACHED */
425 }
426
427 /* VARARGS */
428 void PCAP_NORETURN
bpf_error(compiler_state_t * cstate,const char * fmt,...)429 bpf_error(compiler_state_t *cstate, const char *fmt, ...)
430 {
431 va_list ap;
432
433 va_start(ap, fmt);
434 if (cstate->bpf_pcap != NULL)
435 (void)pcap_vsnprintf(pcap_geterr(cstate->bpf_pcap),
436 PCAP_ERRBUF_SIZE, fmt, ap);
437 va_end(ap);
438 longjmp(cstate->top_ctx, 1);
439 /* NOTREACHED */
440 }
441
442 static void init_linktype(compiler_state_t *, pcap_t *);
443
444 static void init_regs(compiler_state_t *);
445 static int alloc_reg(compiler_state_t *);
446 static void free_reg(compiler_state_t *, int);
447
448 static void initchunks(compiler_state_t *cstate);
449 static void *newchunk(compiler_state_t *cstate, size_t);
450 static void freechunks(compiler_state_t *cstate);
451 static inline struct block *new_block(compiler_state_t *cstate, int);
452 static inline struct slist *new_stmt(compiler_state_t *cstate, int);
453 static struct block *gen_retblk(compiler_state_t *cstate, int);
454 static inline void syntax(compiler_state_t *cstate);
455
456 static void backpatch(struct block *, struct block *);
457 static void merge(struct block *, struct block *);
458 static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
459 u_int, bpf_int32);
460 static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
461 u_int, bpf_int32);
462 static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
463 u_int, bpf_int32);
464 static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
465 u_int, bpf_int32);
466 static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
467 u_int, bpf_int32);
468 static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
469 u_int, bpf_int32, bpf_u_int32);
470 static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
471 u_int, const u_char *);
472 static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, bpf_u_int32,
473 bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32);
474 static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
475 u_int, u_int);
476 static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
477 u_int);
478 static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
479 static struct block *gen_uncond(compiler_state_t *, int);
480 static inline struct block *gen_true(compiler_state_t *);
481 static inline struct block *gen_false(compiler_state_t *);
482 static struct block *gen_ether_linktype(compiler_state_t *, int);
483 static struct block *gen_ipnet_linktype(compiler_state_t *, int);
484 static struct block *gen_linux_sll_linktype(compiler_state_t *, int);
485 static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
486 static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
487 static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
488 static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
489 static void insert_compute_vloffsets(compiler_state_t *, struct block *);
490 static struct slist *gen_abs_offset_varpart(compiler_state_t *,
491 bpf_abs_offset *);
492 static int ethertype_to_ppptype(int);
493 static struct block *gen_linktype(compiler_state_t *, int);
494 static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
495 static struct block *gen_llc_linktype(compiler_state_t *, int);
496 static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
497 int, int, u_int, u_int);
498 #ifdef INET6
499 static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
500 struct in6_addr *, int, int, u_int, u_int);
501 #endif
502 static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
503 static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
504 static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
505 static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
506 static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
507 static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
508 static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
509 static struct block *gen_mpls_linktype(compiler_state_t *, int);
510 static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
511 int, int, int);
512 #ifdef INET6
513 static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
514 struct in6_addr *, int, int, int);
515 #endif
516 #ifndef INET6
517 static struct block *gen_gateway(compiler_state_t *, const u_char *,
518 struct addrinfo *, int, int);
519 #endif
520 static struct block *gen_ipfrag(compiler_state_t *);
521 static struct block *gen_portatom(compiler_state_t *, int, bpf_int32);
522 static struct block *gen_portrangeatom(compiler_state_t *, int, bpf_int32,
523 bpf_int32);
524 static struct block *gen_portatom6(compiler_state_t *, int, bpf_int32);
525 static struct block *gen_portrangeatom6(compiler_state_t *, int, bpf_int32,
526 bpf_int32);
527 struct block *gen_portop(compiler_state_t *, int, int, int);
528 static struct block *gen_port(compiler_state_t *, int, int, int);
529 struct block *gen_portrangeop(compiler_state_t *, int, int, int, int);
530 static struct block *gen_portrange(compiler_state_t *, int, int, int, int);
531 struct block *gen_portop6(compiler_state_t *, int, int, int);
532 static struct block *gen_port6(compiler_state_t *, int, int, int);
533 struct block *gen_portrangeop6(compiler_state_t *, int, int, int, int);
534 static struct block *gen_portrange6(compiler_state_t *, int, int, int, int);
535 static int lookup_proto(compiler_state_t *, const char *, int);
536 static struct block *gen_protochain(compiler_state_t *, int, int, int);
537 static struct block *gen_proto(compiler_state_t *, int, int, int);
538 static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
539 static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
540 static struct block *gen_mac_multicast(compiler_state_t *, int);
541 static struct block *gen_len(compiler_state_t *, int, int);
542 static struct block *gen_check_802_11_data_frame(compiler_state_t *);
543 static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
544
545 static struct block *gen_ppi_dlt_check(compiler_state_t *);
546 static struct block *gen_msg_abbrev(compiler_state_t *, int type);
547
548 static void
initchunks(compiler_state_t * cstate)549 initchunks(compiler_state_t *cstate)
550 {
551 int i;
552
553 for (i = 0; i < NCHUNKS; i++) {
554 cstate->chunks[i].n_left = 0;
555 cstate->chunks[i].m = NULL;
556 }
557 cstate->cur_chunk = 0;
558 }
559
560 static void *
newchunk(compiler_state_t * cstate,size_t n)561 newchunk(compiler_state_t *cstate, size_t n)
562 {
563 struct chunk *cp;
564 int k;
565 size_t size;
566
567 #ifndef __NetBSD__
568 /* XXX Round up to nearest long. */
569 n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
570 #else
571 /* XXX Round up to structure boundary. */
572 n = ALIGN(n);
573 #endif
574
575 cp = &cstate->chunks[cstate->cur_chunk];
576 if (n > cp->n_left) {
577 ++cp;
578 k = ++cstate->cur_chunk;
579 if (k >= NCHUNKS)
580 bpf_error(cstate, "out of memory");
581 size = CHUNK0SIZE << k;
582 cp->m = (void *)malloc(size);
583 if (cp->m == NULL)
584 bpf_error(cstate, "out of memory");
585 memset((char *)cp->m, 0, size);
586 cp->n_left = size;
587 if (n > size)
588 bpf_error(cstate, "out of memory");
589 }
590 cp->n_left -= n;
591 return (void *)((char *)cp->m + cp->n_left);
592 }
593
594 static void
freechunks(compiler_state_t * cstate)595 freechunks(compiler_state_t *cstate)
596 {
597 int i;
598
599 for (i = 0; i < NCHUNKS; ++i)
600 if (cstate->chunks[i].m != NULL)
601 free(cstate->chunks[i].m);
602 }
603
604 /*
605 * A strdup whose allocations are freed after code generation is over.
606 */
607 char *
sdup(compiler_state_t * cstate,const char * s)608 sdup(compiler_state_t *cstate, const char *s)
609 {
610 size_t n = strlen(s) + 1;
611 char *cp = newchunk(cstate, n);
612
613 strlcpy(cp, s, n);
614 return (cp);
615 }
616
617 static inline struct block *
new_block(compiler_state_t * cstate,int code)618 new_block(compiler_state_t *cstate, int code)
619 {
620 struct block *p;
621
622 p = (struct block *)newchunk(cstate, sizeof(*p));
623 p->s.code = code;
624 p->head = p;
625
626 return p;
627 }
628
629 static inline struct slist *
new_stmt(compiler_state_t * cstate,int code)630 new_stmt(compiler_state_t *cstate, int code)
631 {
632 struct slist *p;
633
634 p = (struct slist *)newchunk(cstate, sizeof(*p));
635 p->s.code = code;
636
637 return p;
638 }
639
640 static struct block *
gen_retblk(compiler_state_t * cstate,int v)641 gen_retblk(compiler_state_t *cstate, int v)
642 {
643 struct block *b = new_block(cstate, BPF_RET|BPF_K);
644
645 b->s.k = v;
646 return b;
647 }
648
649 static inline PCAP_NORETURN_DEF void
syntax(compiler_state_t * cstate)650 syntax(compiler_state_t *cstate)
651 {
652 bpf_error(cstate, "syntax error in filter expression");
653 }
654
655 int
pcap_compile(pcap_t * p,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)656 pcap_compile(pcap_t *p, struct bpf_program *program,
657 const char *buf, int optimize, bpf_u_int32 mask)
658 {
659 #ifdef _WIN32
660 static int done = 0;
661 #endif
662 compiler_state_t cstate;
663 const char * volatile xbuf = buf;
664 yyscan_t scanner = NULL;
665 YY_BUFFER_STATE in_buffer = NULL;
666 u_int len;
667 int rc;
668
669 /*
670 * If this pcap_t hasn't been activated, it doesn't have a
671 * link-layer type, so we can't use it.
672 */
673 if (!p->activated) {
674 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
675 "not-yet-activated pcap_t passed to pcap_compile");
676 return (-1);
677 }
678
679 #ifdef _WIN32
680 if (!done)
681 pcap_wsockinit();
682 done = 1;
683 #endif
684
685 #ifdef ENABLE_REMOTE
686 /*
687 * If the device on which we're capturing need to be notified
688 * that a new filter is being compiled, do so.
689 *
690 * This allows them to save a copy of it, in case, for example,
691 * they're implementing a form of remote packet capture, and
692 * want the remote machine to filter out the packets in which
693 * it's sending the packets it's captured.
694 *
695 * XXX - the fact that we happen to be compiling a filter
696 * doesn't necessarily mean we'll be installing it as the
697 * filter for this pcap_t; we might be running it from userland
698 * on captured packets to do packet classification. We really
699 * need a better way of handling this, but this is all that
700 * the WinPcap code did.
701 */
702 if (p->save_current_filter_op != NULL)
703 (p->save_current_filter_op)(p, buf);
704 #endif
705
706 initchunks(&cstate);
707 cstate.no_optimize = 0;
708 #ifdef INET6
709 cstate.ai = NULL;
710 #endif
711 cstate.ic.root = NULL;
712 cstate.ic.cur_mark = 0;
713 cstate.bpf_pcap = p;
714 init_regs(&cstate);
715
716 if (setjmp(cstate.top_ctx)) {
717 #ifdef INET6
718 if (cstate.ai != NULL)
719 freeaddrinfo(cstate.ai);
720 #endif
721 rc = -1;
722 goto quit;
723 }
724
725 cstate.netmask = mask;
726
727 cstate.snaplen = pcap_snapshot(p);
728 if (cstate.snaplen == 0) {
729 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
730 "snaplen of 0 rejects all packets");
731 rc = -1;
732 goto quit;
733 }
734
735 if (pcap_lex_init(&scanner) != 0)
736 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
737 errno, "can't initialize scanner");
738 in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
739
740 /*
741 * Associate the compiler state with the lexical analyzer
742 * state.
743 */
744 pcap_set_extra(&cstate, scanner);
745
746 init_linktype(&cstate, p);
747 (void)pcap_parse(scanner, &cstate);
748
749 if (cstate.ic.root == NULL)
750 cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
751
752 if (optimize && !cstate.no_optimize) {
753 bpf_optimize(&cstate, &cstate.ic);
754 if (cstate.ic.root == NULL ||
755 (cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0))
756 bpf_error(&cstate, "expression rejects all packets");
757 }
758 program->bf_insns = icode_to_fcode(&cstate, &cstate.ic, cstate.ic.root, &len);
759 program->bf_len = len;
760
761 rc = 0; /* We're all okay */
762
763 quit:
764 /*
765 * Clean up everything for the lexical analyzer.
766 */
767 if (in_buffer != NULL)
768 pcap__delete_buffer(in_buffer, scanner);
769 if (scanner != NULL)
770 pcap_lex_destroy(scanner);
771
772 /*
773 * Clean up our own allocated memory.
774 */
775 freechunks(&cstate);
776
777 return (rc);
778 }
779
780 /*
781 * entry point for using the compiler with no pcap open
782 * pass in all the stuff that is needed explicitly instead.
783 */
784 int
pcap_compile_nopcap(int snaplen_arg,int linktype_arg,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)785 pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
786 struct bpf_program *program,
787 const char *buf, int optimize, bpf_u_int32 mask)
788 {
789 pcap_t *p;
790 int ret;
791
792 p = pcap_open_dead(linktype_arg, snaplen_arg);
793 if (p == NULL)
794 return (-1);
795 ret = pcap_compile(p, program, buf, optimize, mask);
796 pcap_close(p);
797 return (ret);
798 }
799
800 /*
801 * Clean up a "struct bpf_program" by freeing all the memory allocated
802 * in it.
803 */
804 void
pcap_freecode(struct bpf_program * program)805 pcap_freecode(struct bpf_program *program)
806 {
807 program->bf_len = 0;
808 if (program->bf_insns != NULL) {
809 free((char *)program->bf_insns);
810 program->bf_insns = NULL;
811 }
812 }
813
814 /*
815 * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
816 * which of the jt and jf fields has been resolved and which is a pointer
817 * back to another unresolved block (or nil). At least one of the fields
818 * in each block is already resolved.
819 */
820 static void
backpatch(struct block * list,struct block * target)821 backpatch(struct block *list, struct block *target)
822 {
823 struct block *next;
824
825 while (list) {
826 if (!list->sense) {
827 next = JT(list);
828 JT(list) = target;
829 } else {
830 next = JF(list);
831 JF(list) = target;
832 }
833 list = next;
834 }
835 }
836
837 /*
838 * Merge the lists in b0 and b1, using the 'sense' field to indicate
839 * which of jt and jf is the link.
840 */
841 static void
merge(struct block * b0,struct block * b1)842 merge(struct block *b0, struct block *b1)
843 {
844 register struct block **p = &b0;
845
846 /* Find end of list. */
847 while (*p)
848 p = !((*p)->sense) ? &JT(*p) : &JF(*p);
849
850 /* Concatenate the lists. */
851 *p = b1;
852 }
853
854 void
finish_parse(compiler_state_t * cstate,struct block * p)855 finish_parse(compiler_state_t *cstate, struct block *p)
856 {
857 struct block *ppi_dlt_check;
858
859 /*
860 * Insert before the statements of the first (root) block any
861 * statements needed to load the lengths of any variable-length
862 * headers into registers.
863 *
864 * XXX - a fancier strategy would be to insert those before the
865 * statements of all blocks that use those lengths and that
866 * have no predecessors that use them, so that we only compute
867 * the lengths if we need them. There might be even better
868 * approaches than that.
869 *
870 * However, those strategies would be more complicated, and
871 * as we don't generate code to compute a length if the
872 * program has no tests that use the length, and as most
873 * tests will probably use those lengths, we would just
874 * postpone computing the lengths so that it's not done
875 * for tests that fail early, and it's not clear that's
876 * worth the effort.
877 */
878 insert_compute_vloffsets(cstate, p->head);
879
880 /*
881 * For DLT_PPI captures, generate a check of the per-packet
882 * DLT value to make sure it's DLT_IEEE802_11.
883 *
884 * XXX - TurboCap cards use DLT_PPI for Ethernet.
885 * Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
886 * with appropriate Ethernet information and use that rather
887 * than using something such as DLT_PPI where you don't know
888 * the link-layer header type until runtime, which, in the
889 * general case, would force us to generate both Ethernet *and*
890 * 802.11 code (*and* anything else for which PPI is used)
891 * and choose between them early in the BPF program?
892 */
893 ppi_dlt_check = gen_ppi_dlt_check(cstate);
894 if (ppi_dlt_check != NULL)
895 gen_and(ppi_dlt_check, p);
896
897 backpatch(p, gen_retblk(cstate, cstate->snaplen));
898 p->sense = !p->sense;
899 backpatch(p, gen_retblk(cstate, 0));
900 cstate->ic.root = p->head;
901 }
902
903 void
gen_and(struct block * b0,struct block * b1)904 gen_and(struct block *b0, struct block *b1)
905 {
906 backpatch(b0, b1->head);
907 b0->sense = !b0->sense;
908 b1->sense = !b1->sense;
909 merge(b1, b0);
910 b1->sense = !b1->sense;
911 b1->head = b0->head;
912 }
913
914 void
gen_or(struct block * b0,struct block * b1)915 gen_or(struct block *b0, struct block *b1)
916 {
917 b0->sense = !b0->sense;
918 backpatch(b0, b1->head);
919 b0->sense = !b0->sense;
920 merge(b1, b0);
921 b1->head = b0->head;
922 }
923
924 void
gen_not(struct block * b)925 gen_not(struct block *b)
926 {
927 b->sense = !b->sense;
928 }
929
930 static struct block *
gen_cmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)931 gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
932 u_int size, bpf_int32 v)
933 {
934 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
935 }
936
937 static struct block *
gen_cmp_gt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)938 gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
939 u_int size, bpf_int32 v)
940 {
941 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
942 }
943
944 static struct block *
gen_cmp_ge(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)945 gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
946 u_int size, bpf_int32 v)
947 {
948 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
949 }
950
951 static struct block *
gen_cmp_lt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)952 gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
953 u_int size, bpf_int32 v)
954 {
955 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
956 }
957
958 static struct block *
gen_cmp_le(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)959 gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
960 u_int size, bpf_int32 v)
961 {
962 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
963 }
964
965 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)966 gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
967 u_int size, bpf_int32 v, bpf_u_int32 mask)
968 {
969 return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
970 }
971
972 static struct block *
gen_bcmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,const u_char * v)973 gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
974 u_int size, const u_char *v)
975 {
976 register struct block *b, *tmp;
977
978 b = NULL;
979 while (size >= 4) {
980 register const u_char *p = &v[size - 4];
981 bpf_int32 w = ((bpf_int32)p[0] << 24) |
982 ((bpf_int32)p[1] << 16) | ((bpf_int32)p[2] << 8) | p[3];
983
984 tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W, w);
985 if (b != NULL)
986 gen_and(b, tmp);
987 b = tmp;
988 size -= 4;
989 }
990 while (size >= 2) {
991 register const u_char *p = &v[size - 2];
992 bpf_int32 w = ((bpf_int32)p[0] << 8) | p[1];
993
994 tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H, w);
995 if (b != NULL)
996 gen_and(b, tmp);
997 b = tmp;
998 size -= 2;
999 }
1000 if (size > 0) {
1001 tmp = gen_cmp(cstate, offrel, offset, BPF_B, (bpf_int32)v[0]);
1002 if (b != NULL)
1003 gen_and(b, tmp);
1004 b = tmp;
1005 }
1006 return b;
1007 }
1008
1009 /*
1010 * AND the field of size "size" at offset "offset" relative to the header
1011 * specified by "offrel" with "mask", and compare it with the value "v"
1012 * with the test specified by "jtype"; if "reverse" is true, the test
1013 * should test the opposite of "jtype".
1014 */
1015 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)1016 gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, bpf_u_int32 offset,
1017 bpf_u_int32 size, bpf_u_int32 mask, bpf_u_int32 jtype, int reverse,
1018 bpf_int32 v)
1019 {
1020 struct slist *s, *s2;
1021 struct block *b;
1022
1023 s = gen_load_a(cstate, offrel, offset, size);
1024
1025 if (mask != 0xffffffff) {
1026 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1027 s2->s.k = mask;
1028 sappend(s, s2);
1029 }
1030
1031 b = new_block(cstate, JMP(jtype));
1032 b->stmts = s;
1033 b->s.k = v;
1034 if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
1035 gen_not(b);
1036 return b;
1037 }
1038
1039 static void
init_linktype(compiler_state_t * cstate,pcap_t * p)1040 init_linktype(compiler_state_t *cstate, pcap_t *p)
1041 {
1042 cstate->pcap_fddipad = p->fddipad;
1043
1044 /*
1045 * We start out with only one link-layer header.
1046 */
1047 cstate->outermostlinktype = pcap_datalink(p);
1048 cstate->off_outermostlinkhdr.constant_part = 0;
1049 cstate->off_outermostlinkhdr.is_variable = 0;
1050 cstate->off_outermostlinkhdr.reg = -1;
1051
1052 cstate->prevlinktype = cstate->outermostlinktype;
1053 cstate->off_prevlinkhdr.constant_part = 0;
1054 cstate->off_prevlinkhdr.is_variable = 0;
1055 cstate->off_prevlinkhdr.reg = -1;
1056
1057 cstate->linktype = cstate->outermostlinktype;
1058 cstate->off_linkhdr.constant_part = 0;
1059 cstate->off_linkhdr.is_variable = 0;
1060 cstate->off_linkhdr.reg = -1;
1061
1062 /*
1063 * XXX
1064 */
1065 cstate->off_linkpl.constant_part = 0;
1066 cstate->off_linkpl.is_variable = 0;
1067 cstate->off_linkpl.reg = -1;
1068
1069 cstate->off_linktype.constant_part = 0;
1070 cstate->off_linktype.is_variable = 0;
1071 cstate->off_linktype.reg = -1;
1072
1073 /*
1074 * Assume it's not raw ATM with a pseudo-header, for now.
1075 */
1076 cstate->is_atm = 0;
1077 cstate->off_vpi = OFFSET_NOT_SET;
1078 cstate->off_vci = OFFSET_NOT_SET;
1079 cstate->off_proto = OFFSET_NOT_SET;
1080 cstate->off_payload = OFFSET_NOT_SET;
1081
1082 /*
1083 * And not Geneve.
1084 */
1085 cstate->is_geneve = 0;
1086
1087 /*
1088 * No variable length VLAN offset by default
1089 */
1090 cstate->is_vlan_vloffset = 0;
1091
1092 /*
1093 * And assume we're not doing SS7.
1094 */
1095 cstate->off_li = OFFSET_NOT_SET;
1096 cstate->off_li_hsl = OFFSET_NOT_SET;
1097 cstate->off_sio = OFFSET_NOT_SET;
1098 cstate->off_opc = OFFSET_NOT_SET;
1099 cstate->off_dpc = OFFSET_NOT_SET;
1100 cstate->off_sls = OFFSET_NOT_SET;
1101
1102 cstate->label_stack_depth = 0;
1103 cstate->vlan_stack_depth = 0;
1104
1105 switch (cstate->linktype) {
1106
1107 case DLT_ARCNET:
1108 cstate->off_linktype.constant_part = 2;
1109 cstate->off_linkpl.constant_part = 6;
1110 cstate->off_nl = 0; /* XXX in reality, variable! */
1111 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1112 break;
1113
1114 case DLT_ARCNET_LINUX:
1115 cstate->off_linktype.constant_part = 4;
1116 cstate->off_linkpl.constant_part = 8;
1117 cstate->off_nl = 0; /* XXX in reality, variable! */
1118 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1119 break;
1120
1121 case DLT_EN10MB:
1122 cstate->off_linktype.constant_part = 12;
1123 cstate->off_linkpl.constant_part = 14; /* Ethernet header length */
1124 cstate->off_nl = 0; /* Ethernet II */
1125 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1126 break;
1127
1128 case DLT_SLIP:
1129 /*
1130 * SLIP doesn't have a link level type. The 16 byte
1131 * header is hacked into our SLIP driver.
1132 */
1133 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1134 cstate->off_linkpl.constant_part = 16;
1135 cstate->off_nl = 0;
1136 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1137 break;
1138
1139 case DLT_SLIP_BSDOS:
1140 /* XXX this may be the same as the DLT_PPP_BSDOS case */
1141 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1142 /* XXX end */
1143 cstate->off_linkpl.constant_part = 24;
1144 cstate->off_nl = 0;
1145 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1146 break;
1147
1148 case DLT_NULL:
1149 case DLT_LOOP:
1150 cstate->off_linktype.constant_part = 0;
1151 cstate->off_linkpl.constant_part = 4;
1152 cstate->off_nl = 0;
1153 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1154 break;
1155
1156 case DLT_ENC:
1157 cstate->off_linktype.constant_part = 0;
1158 cstate->off_linkpl.constant_part = 12;
1159 cstate->off_nl = 0;
1160 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1161 break;
1162
1163 case DLT_PPP:
1164 case DLT_PPP_PPPD:
1165 case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
1166 case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
1167 cstate->off_linktype.constant_part = 2; /* skip HDLC-like framing */
1168 cstate->off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */
1169 cstate->off_nl = 0;
1170 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1171 break;
1172
1173 case DLT_PPP_ETHER:
1174 /*
1175 * This does no include the Ethernet header, and
1176 * only covers session state.
1177 */
1178 cstate->off_linktype.constant_part = 6;
1179 cstate->off_linkpl.constant_part = 8;
1180 cstate->off_nl = 0;
1181 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1182 break;
1183
1184 case DLT_PPP_BSDOS:
1185 cstate->off_linktype.constant_part = 5;
1186 cstate->off_linkpl.constant_part = 24;
1187 cstate->off_nl = 0;
1188 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1189 break;
1190
1191 case DLT_FDDI:
1192 /*
1193 * FDDI doesn't really have a link-level type field.
1194 * We set "off_linktype" to the offset of the LLC header.
1195 *
1196 * To check for Ethernet types, we assume that SSAP = SNAP
1197 * is being used and pick out the encapsulated Ethernet type.
1198 * XXX - should we generate code to check for SNAP?
1199 */
1200 cstate->off_linktype.constant_part = 13;
1201 cstate->off_linktype.constant_part += cstate->pcap_fddipad;
1202 cstate->off_linkpl.constant_part = 13; /* FDDI MAC header length */
1203 cstate->off_linkpl.constant_part += cstate->pcap_fddipad;
1204 cstate->off_nl = 8; /* 802.2+SNAP */
1205 cstate->off_nl_nosnap = 3; /* 802.2 */
1206 break;
1207
1208 case DLT_IEEE802:
1209 /*
1210 * Token Ring doesn't really have a link-level type field.
1211 * We set "off_linktype" to the offset of the LLC header.
1212 *
1213 * To check for Ethernet types, we assume that SSAP = SNAP
1214 * is being used and pick out the encapsulated Ethernet type.
1215 * XXX - should we generate code to check for SNAP?
1216 *
1217 * XXX - the header is actually variable-length.
1218 * Some various Linux patched versions gave 38
1219 * as "off_linktype" and 40 as "off_nl"; however,
1220 * if a token ring packet has *no* routing
1221 * information, i.e. is not source-routed, the correct
1222 * values are 20 and 22, as they are in the vanilla code.
1223 *
1224 * A packet is source-routed iff the uppermost bit
1225 * of the first byte of the source address, at an
1226 * offset of 8, has the uppermost bit set. If the
1227 * packet is source-routed, the total number of bytes
1228 * of routing information is 2 plus bits 0x1F00 of
1229 * the 16-bit value at an offset of 14 (shifted right
1230 * 8 - figure out which byte that is).
1231 */
1232 cstate->off_linktype.constant_part = 14;
1233 cstate->off_linkpl.constant_part = 14; /* Token Ring MAC header length */
1234 cstate->off_nl = 8; /* 802.2+SNAP */
1235 cstate->off_nl_nosnap = 3; /* 802.2 */
1236 break;
1237
1238 case DLT_PRISM_HEADER:
1239 case DLT_IEEE802_11_RADIO_AVS:
1240 case DLT_IEEE802_11_RADIO:
1241 cstate->off_linkhdr.is_variable = 1;
1242 /* Fall through, 802.11 doesn't have a variable link
1243 * prefix but is otherwise the same. */
1244
1245 case DLT_IEEE802_11:
1246 /*
1247 * 802.11 doesn't really have a link-level type field.
1248 * We set "off_linktype.constant_part" to the offset of
1249 * the LLC header.
1250 *
1251 * To check for Ethernet types, we assume that SSAP = SNAP
1252 * is being used and pick out the encapsulated Ethernet type.
1253 * XXX - should we generate code to check for SNAP?
1254 *
1255 * We also handle variable-length radio headers here.
1256 * The Prism header is in theory variable-length, but in
1257 * practice it's always 144 bytes long. However, some
1258 * drivers on Linux use ARPHRD_IEEE80211_PRISM, but
1259 * sometimes or always supply an AVS header, so we
1260 * have to check whether the radio header is a Prism
1261 * header or an AVS header, so, in practice, it's
1262 * variable-length.
1263 */
1264 cstate->off_linktype.constant_part = 24;
1265 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1266 cstate->off_linkpl.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_PPI:
1272 /*
1273 * At the moment we treat PPI the same way that we treat
1274 * normal Radiotap encoded packets. The difference is in
1275 * the function that generates the code at the beginning
1276 * to compute the header length. Since this code generator
1277 * of PPI supports bare 802.11 encapsulation only (i.e.
1278 * the encapsulated DLT should be DLT_IEEE802_11) we
1279 * generate code to check for this too.
1280 */
1281 cstate->off_linktype.constant_part = 24;
1282 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1283 cstate->off_linkpl.is_variable = 1;
1284 cstate->off_linkhdr.is_variable = 1;
1285 cstate->off_nl = 8; /* 802.2+SNAP */
1286 cstate->off_nl_nosnap = 3; /* 802.2 */
1287 break;
1288
1289 case DLT_ATM_RFC1483:
1290 case DLT_ATM_CLIP: /* Linux ATM defines this */
1291 /*
1292 * assume routed, non-ISO PDUs
1293 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1294 *
1295 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1296 * or PPP with the PPP NLPID (e.g., PPPoA)? The
1297 * latter would presumably be treated the way PPPoE
1298 * should be, so you can do "pppoe and udp port 2049"
1299 * or "pppoa and tcp port 80" and have it check for
1300 * PPPo{A,E} and a PPP protocol of IP and....
1301 */
1302 cstate->off_linktype.constant_part = 0;
1303 cstate->off_linkpl.constant_part = 0; /* packet begins with LLC header */
1304 cstate->off_nl = 8; /* 802.2+SNAP */
1305 cstate->off_nl_nosnap = 3; /* 802.2 */
1306 break;
1307
1308 case DLT_SUNATM:
1309 /*
1310 * Full Frontal ATM; you get AALn PDUs with an ATM
1311 * pseudo-header.
1312 */
1313 cstate->is_atm = 1;
1314 cstate->off_vpi = SUNATM_VPI_POS;
1315 cstate->off_vci = SUNATM_VCI_POS;
1316 cstate->off_proto = PROTO_POS;
1317 cstate->off_payload = SUNATM_PKT_BEGIN_POS;
1318 cstate->off_linktype.constant_part = cstate->off_payload;
1319 cstate->off_linkpl.constant_part = cstate->off_payload; /* if LLC-encapsulated */
1320 cstate->off_nl = 8; /* 802.2+SNAP */
1321 cstate->off_nl_nosnap = 3; /* 802.2 */
1322 break;
1323
1324 case DLT_RAW:
1325 case DLT_IPV4:
1326 case DLT_IPV6:
1327 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1328 cstate->off_linkpl.constant_part = 0;
1329 cstate->off_nl = 0;
1330 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1331 break;
1332
1333 case DLT_LINUX_SLL: /* fake header for Linux cooked socket */
1334 cstate->off_linktype.constant_part = 14;
1335 cstate->off_linkpl.constant_part = 16;
1336 cstate->off_nl = 0;
1337 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1338 break;
1339
1340 case DLT_LTALK:
1341 /*
1342 * LocalTalk does have a 1-byte type field in the LLAP header,
1343 * but really it just indicates whether there is a "short" or
1344 * "long" DDP packet following.
1345 */
1346 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1347 cstate->off_linkpl.constant_part = 0;
1348 cstate->off_nl = 0;
1349 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1350 break;
1351
1352 case DLT_IP_OVER_FC:
1353 /*
1354 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1355 * link-level type field. We set "off_linktype" to the
1356 * offset of the LLC header.
1357 *
1358 * To check for Ethernet types, we assume that SSAP = SNAP
1359 * is being used and pick out the encapsulated Ethernet type.
1360 * XXX - should we generate code to check for SNAP? RFC
1361 * 2625 says SNAP should be used.
1362 */
1363 cstate->off_linktype.constant_part = 16;
1364 cstate->off_linkpl.constant_part = 16;
1365 cstate->off_nl = 8; /* 802.2+SNAP */
1366 cstate->off_nl_nosnap = 3; /* 802.2 */
1367 break;
1368
1369 case DLT_FRELAY:
1370 /*
1371 * XXX - we should set this to handle SNAP-encapsulated
1372 * frames (NLPID of 0x80).
1373 */
1374 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1375 cstate->off_linkpl.constant_part = 0;
1376 cstate->off_nl = 0;
1377 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1378 break;
1379
1380 /*
1381 * the only BPF-interesting FRF.16 frames are non-control frames;
1382 * Frame Relay has a variable length link-layer
1383 * so lets start with offset 4 for now and increments later on (FIXME);
1384 */
1385 case DLT_MFR:
1386 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1387 cstate->off_linkpl.constant_part = 0;
1388 cstate->off_nl = 4;
1389 cstate->off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
1390 break;
1391
1392 case DLT_APPLE_IP_OVER_IEEE1394:
1393 cstate->off_linktype.constant_part = 16;
1394 cstate->off_linkpl.constant_part = 18;
1395 cstate->off_nl = 0;
1396 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1397 break;
1398
1399 case DLT_SYMANTEC_FIREWALL:
1400 cstate->off_linktype.constant_part = 6;
1401 cstate->off_linkpl.constant_part = 44;
1402 cstate->off_nl = 0; /* Ethernet II */
1403 cstate->off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
1404 break;
1405
1406 #ifdef HAVE_NET_PFVAR_H
1407 case DLT_PFLOG:
1408 cstate->off_linktype.constant_part = 0;
1409 cstate->off_linkpl.constant_part = PFLOG_HDRLEN;
1410 cstate->off_nl = 0;
1411 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1412 break;
1413 #endif
1414
1415 case DLT_JUNIPER_MFR:
1416 case DLT_JUNIPER_MLFR:
1417 case DLT_JUNIPER_MLPPP:
1418 case DLT_JUNIPER_PPP:
1419 case DLT_JUNIPER_CHDLC:
1420 case DLT_JUNIPER_FRELAY:
1421 cstate->off_linktype.constant_part = 4;
1422 cstate->off_linkpl.constant_part = 4;
1423 cstate->off_nl = 0;
1424 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1425 break;
1426
1427 case DLT_JUNIPER_ATM1:
1428 cstate->off_linktype.constant_part = 4; /* in reality variable between 4-8 */
1429 cstate->off_linkpl.constant_part = 4; /* in reality variable between 4-8 */
1430 cstate->off_nl = 0;
1431 cstate->off_nl_nosnap = 10;
1432 break;
1433
1434 case DLT_JUNIPER_ATM2:
1435 cstate->off_linktype.constant_part = 8; /* in reality variable between 8-12 */
1436 cstate->off_linkpl.constant_part = 8; /* in reality variable between 8-12 */
1437 cstate->off_nl = 0;
1438 cstate->off_nl_nosnap = 10;
1439 break;
1440
1441 /* frames captured on a Juniper PPPoE service PIC
1442 * contain raw ethernet frames */
1443 case DLT_JUNIPER_PPPOE:
1444 case DLT_JUNIPER_ETHER:
1445 cstate->off_linkpl.constant_part = 14;
1446 cstate->off_linktype.constant_part = 16;
1447 cstate->off_nl = 18; /* Ethernet II */
1448 cstate->off_nl_nosnap = 21; /* 802.3+802.2 */
1449 break;
1450
1451 case DLT_JUNIPER_PPPOE_ATM:
1452 cstate->off_linktype.constant_part = 4;
1453 cstate->off_linkpl.constant_part = 6;
1454 cstate->off_nl = 0;
1455 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1456 break;
1457
1458 case DLT_JUNIPER_GGSN:
1459 cstate->off_linktype.constant_part = 6;
1460 cstate->off_linkpl.constant_part = 12;
1461 cstate->off_nl = 0;
1462 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1463 break;
1464
1465 case DLT_JUNIPER_ES:
1466 cstate->off_linktype.constant_part = 6;
1467 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1468 cstate->off_nl = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1469 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1470 break;
1471
1472 case DLT_JUNIPER_MONITOR:
1473 cstate->off_linktype.constant_part = 12;
1474 cstate->off_linkpl.constant_part = 12;
1475 cstate->off_nl = 0; /* raw IP/IP6 header */
1476 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1477 break;
1478
1479 case DLT_BACNET_MS_TP:
1480 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1481 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1482 cstate->off_nl = OFFSET_NOT_SET;
1483 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1484 break;
1485
1486 case DLT_JUNIPER_SERVICES:
1487 cstate->off_linktype.constant_part = 12;
1488 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1489 cstate->off_nl = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1490 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1491 break;
1492
1493 case DLT_JUNIPER_VP:
1494 cstate->off_linktype.constant_part = 18;
1495 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1496 cstate->off_nl = OFFSET_NOT_SET;
1497 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1498 break;
1499
1500 case DLT_JUNIPER_ST:
1501 cstate->off_linktype.constant_part = 18;
1502 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1503 cstate->off_nl = OFFSET_NOT_SET;
1504 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1505 break;
1506
1507 case DLT_JUNIPER_ISM:
1508 cstate->off_linktype.constant_part = 8;
1509 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1510 cstate->off_nl = OFFSET_NOT_SET;
1511 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1512 break;
1513
1514 case DLT_JUNIPER_VS:
1515 case DLT_JUNIPER_SRX_E2E:
1516 case DLT_JUNIPER_FIBRECHANNEL:
1517 case DLT_JUNIPER_ATM_CEMIC:
1518 cstate->off_linktype.constant_part = 8;
1519 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1520 cstate->off_nl = OFFSET_NOT_SET;
1521 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1522 break;
1523
1524 case DLT_MTP2:
1525 cstate->off_li = 2;
1526 cstate->off_li_hsl = 4;
1527 cstate->off_sio = 3;
1528 cstate->off_opc = 4;
1529 cstate->off_dpc = 4;
1530 cstate->off_sls = 7;
1531 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1532 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1533 cstate->off_nl = OFFSET_NOT_SET;
1534 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1535 break;
1536
1537 case DLT_MTP2_WITH_PHDR:
1538 cstate->off_li = 6;
1539 cstate->off_li_hsl = 8;
1540 cstate->off_sio = 7;
1541 cstate->off_opc = 8;
1542 cstate->off_dpc = 8;
1543 cstate->off_sls = 11;
1544 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1545 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1546 cstate->off_nl = OFFSET_NOT_SET;
1547 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1548 break;
1549
1550 case DLT_ERF:
1551 cstate->off_li = 22;
1552 cstate->off_li_hsl = 24;
1553 cstate->off_sio = 23;
1554 cstate->off_opc = 24;
1555 cstate->off_dpc = 24;
1556 cstate->off_sls = 27;
1557 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1558 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1559 cstate->off_nl = OFFSET_NOT_SET;
1560 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1561 break;
1562
1563 case DLT_PFSYNC:
1564 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1565 cstate->off_linkpl.constant_part = 4;
1566 cstate->off_nl = 0;
1567 cstate->off_nl_nosnap = 0;
1568 break;
1569
1570 case DLT_AX25_KISS:
1571 /*
1572 * Currently, only raw "link[N:M]" filtering is supported.
1573 */
1574 cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* variable, min 15, max 71 steps of 7 */
1575 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1576 cstate->off_nl = OFFSET_NOT_SET; /* variable, min 16, max 71 steps of 7 */
1577 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1578 break;
1579
1580 case DLT_IPNET:
1581 cstate->off_linktype.constant_part = 1;
1582 cstate->off_linkpl.constant_part = 24; /* ipnet header length */
1583 cstate->off_nl = 0;
1584 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1585 break;
1586
1587 case DLT_NETANALYZER:
1588 cstate->off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
1589 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1590 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */
1591 cstate->off_nl = 0; /* Ethernet II */
1592 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1593 break;
1594
1595 case DLT_NETANALYZER_TRANSPARENT:
1596 cstate->off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
1597 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1598 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
1599 cstate->off_nl = 0; /* Ethernet II */
1600 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1601 break;
1602
1603 default:
1604 /*
1605 * For values in the range in which we've assigned new
1606 * DLT_ values, only raw "link[N:M]" filtering is supported.
1607 */
1608 if (cstate->linktype >= DLT_MATCHING_MIN &&
1609 cstate->linktype <= DLT_MATCHING_MAX) {
1610 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1611 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1612 cstate->off_nl = OFFSET_NOT_SET;
1613 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1614 } else {
1615 bpf_error(cstate, "unknown data link type %d", cstate->linktype);
1616 }
1617 break;
1618 }
1619
1620 cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr;
1621 }
1622
1623 /*
1624 * Load a value relative to the specified absolute offset.
1625 */
1626 static struct slist *
gen_load_absoffsetrel(compiler_state_t * cstate,bpf_abs_offset * abs_offset,u_int offset,u_int size)1627 gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset,
1628 u_int offset, u_int size)
1629 {
1630 struct slist *s, *s2;
1631
1632 s = gen_abs_offset_varpart(cstate, abs_offset);
1633
1634 /*
1635 * If "s" is non-null, it has code to arrange that the X register
1636 * contains the variable part of the absolute offset, so we
1637 * generate a load relative to that, with an offset of
1638 * abs_offset->constant_part + offset.
1639 *
1640 * Otherwise, we can do an absolute load with an offset of
1641 * abs_offset->constant_part + offset.
1642 */
1643 if (s != NULL) {
1644 /*
1645 * "s" points to a list of statements that puts the
1646 * variable part of the absolute offset into the X register.
1647 * Do an indirect load, to use the X register as an offset.
1648 */
1649 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1650 s2->s.k = abs_offset->constant_part + offset;
1651 sappend(s, s2);
1652 } else {
1653 /*
1654 * There is no variable part of the absolute offset, so
1655 * just do an absolute load.
1656 */
1657 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1658 s->s.k = abs_offset->constant_part + offset;
1659 }
1660 return s;
1661 }
1662
1663 /*
1664 * Load a value relative to the beginning of the specified header.
1665 */
1666 static struct slist *
gen_load_a(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size)1667 gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1668 u_int size)
1669 {
1670 struct slist *s, *s2;
1671
1672 switch (offrel) {
1673
1674 case OR_PACKET:
1675 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1676 s->s.k = offset;
1677 break;
1678
1679 case OR_LINKHDR:
1680 s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size);
1681 break;
1682
1683 case OR_PREVLINKHDR:
1684 s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size);
1685 break;
1686
1687 case OR_LLC:
1688 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size);
1689 break;
1690
1691 case OR_PREVMPLSHDR:
1692 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size);
1693 break;
1694
1695 case OR_LINKPL:
1696 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size);
1697 break;
1698
1699 case OR_LINKPL_NOSNAP:
1700 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size);
1701 break;
1702
1703 case OR_LINKTYPE:
1704 s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size);
1705 break;
1706
1707 case OR_TRAN_IPV4:
1708 /*
1709 * Load the X register with the length of the IPv4 header
1710 * (plus the offset of the link-layer header, if it's
1711 * preceded by a variable-length header such as a radio
1712 * header), in bytes.
1713 */
1714 s = gen_loadx_iphdrlen(cstate);
1715
1716 /*
1717 * Load the item at {offset of the link-layer payload} +
1718 * {offset, relative to the start of the link-layer
1719 * paylod, of the IPv4 header} + {length of the IPv4 header} +
1720 * {specified offset}.
1721 *
1722 * If the offset of the link-layer payload is variable,
1723 * the variable part of that offset is included in the
1724 * value in the X register, and we include the constant
1725 * part in the offset of the load.
1726 */
1727 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1728 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset;
1729 sappend(s, s2);
1730 break;
1731
1732 case OR_TRAN_IPV6:
1733 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size);
1734 break;
1735
1736 default:
1737 abort();
1738 /* NOTREACHED */
1739 }
1740 return s;
1741 }
1742
1743 /*
1744 * Generate code to load into the X register the sum of the length of
1745 * the IPv4 header and the variable part of the offset of the link-layer
1746 * payload.
1747 */
1748 static struct slist *
gen_loadx_iphdrlen(compiler_state_t * cstate)1749 gen_loadx_iphdrlen(compiler_state_t *cstate)
1750 {
1751 struct slist *s, *s2;
1752
1753 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
1754 if (s != NULL) {
1755 /*
1756 * The offset of the link-layer payload has a variable
1757 * part. "s" points to a list of statements that put
1758 * the variable part of that offset into the X register.
1759 *
1760 * The 4*([k]&0xf) addressing mode can't be used, as we
1761 * don't have a constant offset, so we have to load the
1762 * value in question into the A register and add to it
1763 * the value from the X register.
1764 */
1765 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
1766 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1767 sappend(s, s2);
1768 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1769 s2->s.k = 0xf;
1770 sappend(s, s2);
1771 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
1772 s2->s.k = 2;
1773 sappend(s, s2);
1774
1775 /*
1776 * The A register now contains the length of the IP header.
1777 * We need to add to it the variable part of the offset of
1778 * the link-layer payload, which is still in the X
1779 * register, and move the result into the X register.
1780 */
1781 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
1782 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
1783 } else {
1784 /*
1785 * The offset of the link-layer payload is a constant,
1786 * so no code was generated to load the (non-existent)
1787 * variable part of that offset.
1788 *
1789 * This means we can use the 4*([k]&0xf) addressing
1790 * mode. Load the length of the IPv4 header, which
1791 * is at an offset of cstate->off_nl from the beginning of
1792 * the link-layer payload, and thus at an offset of
1793 * cstate->off_linkpl.constant_part + cstate->off_nl from the beginning
1794 * of the raw packet data, using that addressing mode.
1795 */
1796 s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
1797 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1798 }
1799 return s;
1800 }
1801
1802
1803 static struct block *
gen_uncond(compiler_state_t * cstate,int rsense)1804 gen_uncond(compiler_state_t *cstate, int rsense)
1805 {
1806 struct block *b;
1807 struct slist *s;
1808
1809 s = new_stmt(cstate, BPF_LD|BPF_IMM);
1810 s->s.k = !rsense;
1811 b = new_block(cstate, JMP(BPF_JEQ));
1812 b->stmts = s;
1813
1814 return b;
1815 }
1816
1817 static inline struct block *
gen_true(compiler_state_t * cstate)1818 gen_true(compiler_state_t *cstate)
1819 {
1820 return gen_uncond(cstate, 1);
1821 }
1822
1823 static inline struct block *
gen_false(compiler_state_t * cstate)1824 gen_false(compiler_state_t *cstate)
1825 {
1826 return gen_uncond(cstate, 0);
1827 }
1828
1829 /*
1830 * Byte-swap a 32-bit number.
1831 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1832 * big-endian platforms.)
1833 */
1834 #define SWAPLONG(y) \
1835 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1836
1837 /*
1838 * Generate code to match a particular packet type.
1839 *
1840 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1841 * value, if <= ETHERMTU. We use that to determine whether to
1842 * match the type/length field or to check the type/length field for
1843 * a value <= ETHERMTU to see whether it's a type field and then do
1844 * the appropriate test.
1845 */
1846 static struct block *
gen_ether_linktype(compiler_state_t * cstate,int proto)1847 gen_ether_linktype(compiler_state_t *cstate, int proto)
1848 {
1849 struct block *b0, *b1;
1850
1851 switch (proto) {
1852
1853 case LLCSAP_ISONS:
1854 case LLCSAP_IP:
1855 case LLCSAP_NETBEUI:
1856 /*
1857 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1858 * so we check the DSAP and SSAP.
1859 *
1860 * LLCSAP_IP checks for IP-over-802.2, rather
1861 * than IP-over-Ethernet or IP-over-SNAP.
1862 *
1863 * XXX - should we check both the DSAP and the
1864 * SSAP, like this, or should we check just the
1865 * DSAP, as we do for other types <= ETHERMTU
1866 * (i.e., other SAP values)?
1867 */
1868 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1869 gen_not(b0);
1870 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
1871 ((proto << 8) | proto));
1872 gen_and(b0, b1);
1873 return b1;
1874
1875 case LLCSAP_IPX:
1876 /*
1877 * Check for;
1878 *
1879 * Ethernet_II frames, which are Ethernet
1880 * frames with a frame type of ETHERTYPE_IPX;
1881 *
1882 * Ethernet_802.3 frames, which are 802.3
1883 * frames (i.e., the type/length field is
1884 * a length field, <= ETHERMTU, rather than
1885 * a type field) with the first two bytes
1886 * after the Ethernet/802.3 header being
1887 * 0xFFFF;
1888 *
1889 * Ethernet_802.2 frames, which are 802.3
1890 * frames with an 802.2 LLC header and
1891 * with the IPX LSAP as the DSAP in the LLC
1892 * header;
1893 *
1894 * Ethernet_SNAP frames, which are 802.3
1895 * frames with an LLC header and a SNAP
1896 * header and with an OUI of 0x000000
1897 * (encapsulated Ethernet) and a protocol
1898 * ID of ETHERTYPE_IPX in the SNAP header.
1899 *
1900 * XXX - should we generate the same code both
1901 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
1902 */
1903
1904 /*
1905 * This generates code to check both for the
1906 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
1907 */
1908 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
1909 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
1910 gen_or(b0, b1);
1911
1912 /*
1913 * Now we add code to check for SNAP frames with
1914 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
1915 */
1916 b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
1917 gen_or(b0, b1);
1918
1919 /*
1920 * Now we generate code to check for 802.3
1921 * frames in general.
1922 */
1923 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1924 gen_not(b0);
1925
1926 /*
1927 * Now add the check for 802.3 frames before the
1928 * check for Ethernet_802.2 and Ethernet_802.3,
1929 * as those checks should only be done on 802.3
1930 * frames, not on Ethernet frames.
1931 */
1932 gen_and(b0, b1);
1933
1934 /*
1935 * Now add the check for Ethernet_II frames, and
1936 * do that before checking for the other frame
1937 * types.
1938 */
1939 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
1940 gen_or(b0, b1);
1941 return b1;
1942
1943 case ETHERTYPE_ATALK:
1944 case ETHERTYPE_AARP:
1945 /*
1946 * EtherTalk (AppleTalk protocols on Ethernet link
1947 * layer) may use 802.2 encapsulation.
1948 */
1949
1950 /*
1951 * Check for 802.2 encapsulation (EtherTalk phase 2?);
1952 * we check for an Ethernet type field less than
1953 * 1500, which means it's an 802.3 length field.
1954 */
1955 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1956 gen_not(b0);
1957
1958 /*
1959 * 802.2-encapsulated ETHERTYPE_ATALK packets are
1960 * SNAP packets with an organization code of
1961 * 0x080007 (Apple, for Appletalk) and a protocol
1962 * type of ETHERTYPE_ATALK (Appletalk).
1963 *
1964 * 802.2-encapsulated ETHERTYPE_AARP packets are
1965 * SNAP packets with an organization code of
1966 * 0x000000 (encapsulated Ethernet) and a protocol
1967 * type of ETHERTYPE_AARP (Appletalk ARP).
1968 */
1969 if (proto == ETHERTYPE_ATALK)
1970 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
1971 else /* proto == ETHERTYPE_AARP */
1972 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
1973 gen_and(b0, b1);
1974
1975 /*
1976 * Check for Ethernet encapsulation (Ethertalk
1977 * phase 1?); we just check for the Ethernet
1978 * protocol type.
1979 */
1980 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
1981
1982 gen_or(b0, b1);
1983 return b1;
1984
1985 default:
1986 if (proto <= ETHERMTU) {
1987 /*
1988 * This is an LLC SAP value, so the frames
1989 * that match would be 802.2 frames.
1990 * Check that the frame is an 802.2 frame
1991 * (i.e., that the length/type field is
1992 * a length field, <= ETHERMTU) and
1993 * then check the DSAP.
1994 */
1995 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1996 gen_not(b0);
1997 b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, (bpf_int32)proto);
1998 gen_and(b0, b1);
1999 return b1;
2000 } else {
2001 /*
2002 * This is an Ethernet type, so compare
2003 * the length/type field with it (if
2004 * the frame is an 802.2 frame, the length
2005 * field will be <= ETHERMTU, and, as
2006 * "proto" is > ETHERMTU, this test
2007 * will fail and the frame won't match,
2008 * which is what we want).
2009 */
2010 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
2011 (bpf_int32)proto);
2012 }
2013 }
2014 }
2015
2016 static struct block *
gen_loopback_linktype(compiler_state_t * cstate,int proto)2017 gen_loopback_linktype(compiler_state_t *cstate, int proto)
2018 {
2019 /*
2020 * For DLT_NULL, the link-layer header is a 32-bit word
2021 * containing an AF_ value in *host* byte order, and for
2022 * DLT_ENC, the link-layer header begins with a 32-bit
2023 * word containing an AF_ value in host byte order.
2024 *
2025 * In addition, if we're reading a saved capture file,
2026 * the host byte order in the capture may not be the
2027 * same as the host byte order on this machine.
2028 *
2029 * For DLT_LOOP, the link-layer header is a 32-bit
2030 * word containing an AF_ value in *network* byte order.
2031 */
2032 if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) {
2033 /*
2034 * The AF_ value is in host byte order, but the BPF
2035 * interpreter will convert it to network byte order.
2036 *
2037 * If this is a save file, and it's from a machine
2038 * with the opposite byte order to ours, we byte-swap
2039 * the AF_ value.
2040 *
2041 * Then we run it through "htonl()", and generate
2042 * code to compare against the result.
2043 */
2044 if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped)
2045 proto = SWAPLONG(proto);
2046 proto = htonl(proto);
2047 }
2048 return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, (bpf_int32)proto));
2049 }
2050
2051 /*
2052 * "proto" is an Ethernet type value and for IPNET, if it is not IPv4
2053 * or IPv6 then we have an error.
2054 */
2055 static struct block *
gen_ipnet_linktype(compiler_state_t * cstate,int proto)2056 gen_ipnet_linktype(compiler_state_t *cstate, int proto)
2057 {
2058 switch (proto) {
2059
2060 case ETHERTYPE_IP:
2061 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, (bpf_int32)IPH_AF_INET);
2062 /* NOTREACHED */
2063
2064 case ETHERTYPE_IPV6:
2065 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
2066 (bpf_int32)IPH_AF_INET6);
2067 /* NOTREACHED */
2068
2069 default:
2070 break;
2071 }
2072
2073 return gen_false(cstate);
2074 }
2075
2076 /*
2077 * Generate code to match a particular packet type.
2078 *
2079 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2080 * value, if <= ETHERMTU. We use that to determine whether to
2081 * match the type field or to check the type field for the special
2082 * LINUX_SLL_P_802_2 value and then do the appropriate test.
2083 */
2084 static struct block *
gen_linux_sll_linktype(compiler_state_t * cstate,int proto)2085 gen_linux_sll_linktype(compiler_state_t *cstate, int proto)
2086 {
2087 struct block *b0, *b1;
2088
2089 switch (proto) {
2090
2091 case LLCSAP_ISONS:
2092 case LLCSAP_IP:
2093 case LLCSAP_NETBEUI:
2094 /*
2095 * OSI protocols and NetBEUI always use 802.2 encapsulation,
2096 * so we check the DSAP and SSAP.
2097 *
2098 * LLCSAP_IP checks for IP-over-802.2, rather
2099 * than IP-over-Ethernet or IP-over-SNAP.
2100 *
2101 * XXX - should we check both the DSAP and the
2102 * SSAP, like this, or should we check just the
2103 * DSAP, as we do for other types <= ETHERMTU
2104 * (i.e., other SAP values)?
2105 */
2106 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2107 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
2108 ((proto << 8) | proto));
2109 gen_and(b0, b1);
2110 return b1;
2111
2112 case LLCSAP_IPX:
2113 /*
2114 * Ethernet_II frames, which are Ethernet
2115 * frames with a frame type of ETHERTYPE_IPX;
2116 *
2117 * Ethernet_802.3 frames, which have a frame
2118 * type of LINUX_SLL_P_802_3;
2119 *
2120 * Ethernet_802.2 frames, which are 802.3
2121 * frames with an 802.2 LLC header (i.e, have
2122 * a frame type of LINUX_SLL_P_802_2) and
2123 * with the IPX LSAP as the DSAP in the LLC
2124 * header;
2125 *
2126 * Ethernet_SNAP frames, which are 802.3
2127 * frames with an LLC header and a SNAP
2128 * header and with an OUI of 0x000000
2129 * (encapsulated Ethernet) and a protocol
2130 * ID of ETHERTYPE_IPX in the SNAP header.
2131 *
2132 * First, do the checks on LINUX_SLL_P_802_2
2133 * frames; generate the check for either
2134 * Ethernet_802.2 or Ethernet_SNAP frames, and
2135 * then put a check for LINUX_SLL_P_802_2 frames
2136 * before it.
2137 */
2138 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
2139 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
2140 gen_or(b0, b1);
2141 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2142 gen_and(b0, b1);
2143
2144 /*
2145 * Now check for 802.3 frames and OR that with
2146 * the previous test.
2147 */
2148 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3);
2149 gen_or(b0, b1);
2150
2151 /*
2152 * Now add the check for Ethernet_II frames, and
2153 * do that before checking for the other frame
2154 * types.
2155 */
2156 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
2157 gen_or(b0, b1);
2158 return b1;
2159
2160 case ETHERTYPE_ATALK:
2161 case ETHERTYPE_AARP:
2162 /*
2163 * EtherTalk (AppleTalk protocols on Ethernet link
2164 * layer) may use 802.2 encapsulation.
2165 */
2166
2167 /*
2168 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2169 * we check for the 802.2 protocol type in the
2170 * "Ethernet type" field.
2171 */
2172 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2173
2174 /*
2175 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2176 * SNAP packets with an organization code of
2177 * 0x080007 (Apple, for Appletalk) and a protocol
2178 * type of ETHERTYPE_ATALK (Appletalk).
2179 *
2180 * 802.2-encapsulated ETHERTYPE_AARP packets are
2181 * SNAP packets with an organization code of
2182 * 0x000000 (encapsulated Ethernet) and a protocol
2183 * type of ETHERTYPE_AARP (Appletalk ARP).
2184 */
2185 if (proto == ETHERTYPE_ATALK)
2186 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
2187 else /* proto == ETHERTYPE_AARP */
2188 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
2189 gen_and(b0, b1);
2190
2191 /*
2192 * Check for Ethernet encapsulation (Ethertalk
2193 * phase 1?); we just check for the Ethernet
2194 * protocol type.
2195 */
2196 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2197
2198 gen_or(b0, b1);
2199 return b1;
2200
2201 default:
2202 if (proto <= ETHERMTU) {
2203 /*
2204 * This is an LLC SAP value, so the frames
2205 * that match would be 802.2 frames.
2206 * Check for the 802.2 protocol type
2207 * in the "Ethernet type" field, and
2208 * then check the DSAP.
2209 */
2210 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2211 b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B,
2212 (bpf_int32)proto);
2213 gen_and(b0, b1);
2214 return b1;
2215 } else {
2216 /*
2217 * This is an Ethernet type, so compare
2218 * the length/type field with it (if
2219 * the frame is an 802.2 frame, the length
2220 * field will be <= ETHERMTU, and, as
2221 * "proto" is > ETHERMTU, this test
2222 * will fail and the frame won't match,
2223 * which is what we want).
2224 */
2225 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2226 }
2227 }
2228 }
2229
2230 static struct slist *
gen_load_prism_llprefixlen(compiler_state_t * cstate)2231 gen_load_prism_llprefixlen(compiler_state_t *cstate)
2232 {
2233 struct slist *s1, *s2;
2234 struct slist *sjeq_avs_cookie;
2235 struct slist *sjcommon;
2236
2237 /*
2238 * This code is not compatible with the optimizer, as
2239 * we are generating jmp instructions within a normal
2240 * slist of instructions
2241 */
2242 cstate->no_optimize = 1;
2243
2244 /*
2245 * Generate code to load the length of the radio header into
2246 * the register assigned to hold that length, if one has been
2247 * assigned. (If one hasn't been assigned, no code we've
2248 * generated uses that prefix, so we don't need to generate any
2249 * code to load it.)
2250 *
2251 * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
2252 * or always use the AVS header rather than the Prism header.
2253 * We load a 4-byte big-endian value at the beginning of the
2254 * raw packet data, and see whether, when masked with 0xFFFFF000,
2255 * it's equal to 0x80211000. If so, that indicates that it's
2256 * an AVS header (the masked-out bits are the version number).
2257 * Otherwise, it's a Prism header.
2258 *
2259 * XXX - the Prism header is also, in theory, variable-length,
2260 * but no known software generates headers that aren't 144
2261 * bytes long.
2262 */
2263 if (cstate->off_linkhdr.reg != -1) {
2264 /*
2265 * Load the cookie.
2266 */
2267 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2268 s1->s.k = 0;
2269
2270 /*
2271 * AND it with 0xFFFFF000.
2272 */
2273 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
2274 s2->s.k = 0xFFFFF000;
2275 sappend(s1, s2);
2276
2277 /*
2278 * Compare with 0x80211000.
2279 */
2280 sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ));
2281 sjeq_avs_cookie->s.k = 0x80211000;
2282 sappend(s1, sjeq_avs_cookie);
2283
2284 /*
2285 * If it's AVS:
2286 *
2287 * The 4 bytes at an offset of 4 from the beginning of
2288 * the AVS header are the length of the AVS header.
2289 * That field is big-endian.
2290 */
2291 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2292 s2->s.k = 4;
2293 sappend(s1, s2);
2294 sjeq_avs_cookie->s.jt = s2;
2295
2296 /*
2297 * Now jump to the code to allocate a register
2298 * into which to save the header length and
2299 * store the length there. (The "jump always"
2300 * instruction needs to have the k field set;
2301 * it's added to the PC, so, as we're jumping
2302 * over a single instruction, it should be 1.)
2303 */
2304 sjcommon = new_stmt(cstate, JMP(BPF_JA));
2305 sjcommon->s.k = 1;
2306 sappend(s1, sjcommon);
2307
2308 /*
2309 * Now for the code that handles the Prism header.
2310 * Just load the length of the Prism header (144)
2311 * into the A register. Have the test for an AVS
2312 * header branch here if we don't have an AVS header.
2313 */
2314 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2315 s2->s.k = 144;
2316 sappend(s1, s2);
2317 sjeq_avs_cookie->s.jf = s2;
2318
2319 /*
2320 * Now allocate a register to hold that value and store
2321 * it. The code for the AVS header will jump here after
2322 * loading the length of the AVS header.
2323 */
2324 s2 = new_stmt(cstate, BPF_ST);
2325 s2->s.k = cstate->off_linkhdr.reg;
2326 sappend(s1, s2);
2327 sjcommon->s.jf = s2;
2328
2329 /*
2330 * Now move it into the X register.
2331 */
2332 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2333 sappend(s1, s2);
2334
2335 return (s1);
2336 } else
2337 return (NULL);
2338 }
2339
2340 static struct slist *
gen_load_avs_llprefixlen(compiler_state_t * cstate)2341 gen_load_avs_llprefixlen(compiler_state_t *cstate)
2342 {
2343 struct slist *s1, *s2;
2344
2345 /*
2346 * Generate code to load the length of the AVS header into
2347 * the register assigned to hold that length, if one has been
2348 * assigned. (If one hasn't been assigned, no code we've
2349 * generated uses that prefix, so we don't need to generate any
2350 * code to load it.)
2351 */
2352 if (cstate->off_linkhdr.reg != -1) {
2353 /*
2354 * The 4 bytes at an offset of 4 from the beginning of
2355 * the AVS header are the length of the AVS header.
2356 * That field is big-endian.
2357 */
2358 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2359 s1->s.k = 4;
2360
2361 /*
2362 * Now allocate a register to hold that value and store
2363 * it.
2364 */
2365 s2 = new_stmt(cstate, BPF_ST);
2366 s2->s.k = cstate->off_linkhdr.reg;
2367 sappend(s1, s2);
2368
2369 /*
2370 * Now move it into the X register.
2371 */
2372 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2373 sappend(s1, s2);
2374
2375 return (s1);
2376 } else
2377 return (NULL);
2378 }
2379
2380 static struct slist *
gen_load_radiotap_llprefixlen(compiler_state_t * cstate)2381 gen_load_radiotap_llprefixlen(compiler_state_t *cstate)
2382 {
2383 struct slist *s1, *s2;
2384
2385 /*
2386 * Generate code to load the length of the radiotap header into
2387 * the register assigned to hold that length, if one has been
2388 * assigned. (If one hasn't been assigned, no code we've
2389 * generated uses that prefix, so we don't need to generate any
2390 * code to load it.)
2391 */
2392 if (cstate->off_linkhdr.reg != -1) {
2393 /*
2394 * The 2 bytes at offsets of 2 and 3 from the beginning
2395 * of the radiotap header are the length of the radiotap
2396 * header; unfortunately, it's little-endian, so we have
2397 * to load it a byte at a time and construct the value.
2398 */
2399
2400 /*
2401 * Load the high-order byte, at an offset of 3, shift it
2402 * left a byte, and put the result in the X register.
2403 */
2404 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2405 s1->s.k = 3;
2406 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2407 sappend(s1, s2);
2408 s2->s.k = 8;
2409 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2410 sappend(s1, s2);
2411
2412 /*
2413 * Load the next byte, at an offset of 2, and OR the
2414 * value from the X register into it.
2415 */
2416 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2417 sappend(s1, s2);
2418 s2->s.k = 2;
2419 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2420 sappend(s1, s2);
2421
2422 /*
2423 * Now allocate a register to hold that value and store
2424 * it.
2425 */
2426 s2 = new_stmt(cstate, BPF_ST);
2427 s2->s.k = cstate->off_linkhdr.reg;
2428 sappend(s1, s2);
2429
2430 /*
2431 * Now move it into the X register.
2432 */
2433 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2434 sappend(s1, s2);
2435
2436 return (s1);
2437 } else
2438 return (NULL);
2439 }
2440
2441 /*
2442 * At the moment we treat PPI as normal Radiotap encoded
2443 * packets. The difference is in the function that generates
2444 * the code at the beginning to compute the header length.
2445 * Since this code generator of PPI supports bare 802.11
2446 * encapsulation only (i.e. the encapsulated DLT should be
2447 * DLT_IEEE802_11) we generate code to check for this too;
2448 * that's done in finish_parse().
2449 */
2450 static struct slist *
gen_load_ppi_llprefixlen(compiler_state_t * cstate)2451 gen_load_ppi_llprefixlen(compiler_state_t *cstate)
2452 {
2453 struct slist *s1, *s2;
2454
2455 /*
2456 * Generate code to load the length of the radiotap header
2457 * into the register assigned to hold that length, if one has
2458 * been assigned.
2459 */
2460 if (cstate->off_linkhdr.reg != -1) {
2461 /*
2462 * The 2 bytes at offsets of 2 and 3 from the beginning
2463 * of the radiotap header are the length of the radiotap
2464 * header; unfortunately, it's little-endian, so we have
2465 * to load it a byte at a time and construct the value.
2466 */
2467
2468 /*
2469 * Load the high-order byte, at an offset of 3, shift it
2470 * left a byte, and put the result in the X register.
2471 */
2472 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2473 s1->s.k = 3;
2474 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2475 sappend(s1, s2);
2476 s2->s.k = 8;
2477 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2478 sappend(s1, s2);
2479
2480 /*
2481 * Load the next byte, at an offset of 2, and OR the
2482 * value from the X register into it.
2483 */
2484 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2485 sappend(s1, s2);
2486 s2->s.k = 2;
2487 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2488 sappend(s1, s2);
2489
2490 /*
2491 * Now allocate a register to hold that value and store
2492 * it.
2493 */
2494 s2 = new_stmt(cstate, BPF_ST);
2495 s2->s.k = cstate->off_linkhdr.reg;
2496 sappend(s1, s2);
2497
2498 /*
2499 * Now move it into the X register.
2500 */
2501 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2502 sappend(s1, s2);
2503
2504 return (s1);
2505 } else
2506 return (NULL);
2507 }
2508
2509 /*
2510 * Load a value relative to the beginning of the link-layer header after the 802.11
2511 * header, i.e. LLC_SNAP.
2512 * The link-layer header doesn't necessarily begin at the beginning
2513 * of the packet data; there might be a variable-length prefix containing
2514 * radio information.
2515 */
2516 static struct slist *
gen_load_802_11_header_len(compiler_state_t * cstate,struct slist * s,struct slist * snext)2517 gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext)
2518 {
2519 struct slist *s2;
2520 struct slist *sjset_data_frame_1;
2521 struct slist *sjset_data_frame_2;
2522 struct slist *sjset_qos;
2523 struct slist *sjset_radiotap_flags_present;
2524 struct slist *sjset_radiotap_ext_present;
2525 struct slist *sjset_radiotap_tsft_present;
2526 struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
2527 struct slist *s_roundup;
2528
2529 if (cstate->off_linkpl.reg == -1) {
2530 /*
2531 * No register has been assigned to the offset of
2532 * the link-layer payload, which means nobody needs
2533 * it; don't bother computing it - just return
2534 * what we already have.
2535 */
2536 return (s);
2537 }
2538
2539 /*
2540 * This code is not compatible with the optimizer, as
2541 * we are generating jmp instructions within a normal
2542 * slist of instructions
2543 */
2544 cstate->no_optimize = 1;
2545
2546 /*
2547 * If "s" is non-null, it has code to arrange that the X register
2548 * contains the length of the prefix preceding the link-layer
2549 * header.
2550 *
2551 * Otherwise, the length of the prefix preceding the link-layer
2552 * header is "off_outermostlinkhdr.constant_part".
2553 */
2554 if (s == NULL) {
2555 /*
2556 * There is no variable-length header preceding the
2557 * link-layer header.
2558 *
2559 * Load the length of the fixed-length prefix preceding
2560 * the link-layer header (if any) into the X register,
2561 * and store it in the cstate->off_linkpl.reg register.
2562 * That length is off_outermostlinkhdr.constant_part.
2563 */
2564 s = new_stmt(cstate, BPF_LDX|BPF_IMM);
2565 s->s.k = cstate->off_outermostlinkhdr.constant_part;
2566 }
2567
2568 /*
2569 * The X register contains the offset of the beginning of the
2570 * link-layer header; add 24, which is the minimum length
2571 * of the MAC header for a data frame, to that, and store it
2572 * in cstate->off_linkpl.reg, and then load the Frame Control field,
2573 * which is at the offset in the X register, with an indexed load.
2574 */
2575 s2 = new_stmt(cstate, BPF_MISC|BPF_TXA);
2576 sappend(s, s2);
2577 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
2578 s2->s.k = 24;
2579 sappend(s, s2);
2580 s2 = new_stmt(cstate, BPF_ST);
2581 s2->s.k = cstate->off_linkpl.reg;
2582 sappend(s, s2);
2583
2584 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
2585 s2->s.k = 0;
2586 sappend(s, s2);
2587
2588 /*
2589 * Check the Frame Control field to see if this is a data frame;
2590 * a data frame has the 0x08 bit (b3) in that field set and the
2591 * 0x04 bit (b2) clear.
2592 */
2593 sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET));
2594 sjset_data_frame_1->s.k = 0x08;
2595 sappend(s, sjset_data_frame_1);
2596
2597 /*
2598 * If b3 is set, test b2, otherwise go to the first statement of
2599 * the rest of the program.
2600 */
2601 sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET));
2602 sjset_data_frame_2->s.k = 0x04;
2603 sappend(s, sjset_data_frame_2);
2604 sjset_data_frame_1->s.jf = snext;
2605
2606 /*
2607 * If b2 is not set, this is a data frame; test the QoS bit.
2608 * Otherwise, go to the first statement of the rest of the
2609 * program.
2610 */
2611 sjset_data_frame_2->s.jt = snext;
2612 sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET));
2613 sjset_qos->s.k = 0x80; /* QoS bit */
2614 sappend(s, sjset_qos);
2615
2616 /*
2617 * If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS
2618 * field.
2619 * Otherwise, go to the first statement of the rest of the
2620 * program.
2621 */
2622 sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
2623 s2->s.k = cstate->off_linkpl.reg;
2624 sappend(s, s2);
2625 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2626 s2->s.k = 2;
2627 sappend(s, s2);
2628 s2 = new_stmt(cstate, BPF_ST);
2629 s2->s.k = cstate->off_linkpl.reg;
2630 sappend(s, s2);
2631
2632 /*
2633 * If we have a radiotap header, look at it to see whether
2634 * there's Atheros padding between the MAC-layer header
2635 * and the payload.
2636 *
2637 * Note: all of the fields in the radiotap header are
2638 * little-endian, so we byte-swap all of the values
2639 * we test against, as they will be loaded as big-endian
2640 * values.
2641 *
2642 * XXX - in the general case, we would have to scan through
2643 * *all* the presence bits, if there's more than one word of
2644 * presence bits. That would require a loop, meaning that
2645 * we wouldn't be able to run the filter in the kernel.
2646 *
2647 * We assume here that the Atheros adapters that insert the
2648 * annoying padding don't have multiple antennae and therefore
2649 * do not generate radiotap headers with multiple presence words.
2650 */
2651 if (cstate->linktype == DLT_IEEE802_11_RADIO) {
2652 /*
2653 * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
2654 * in the first presence flag word?
2655 */
2656 sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W);
2657 s2->s.k = 4;
2658 sappend(s, s2);
2659
2660 sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET));
2661 sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002);
2662 sappend(s, sjset_radiotap_flags_present);
2663
2664 /*
2665 * If not, skip all of this.
2666 */
2667 sjset_radiotap_flags_present->s.jf = snext;
2668
2669 /*
2670 * Otherwise, is the "extension" bit set in that word?
2671 */
2672 sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET));
2673 sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000);
2674 sappend(s, sjset_radiotap_ext_present);
2675 sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present;
2676
2677 /*
2678 * If so, skip all of this.
2679 */
2680 sjset_radiotap_ext_present->s.jt = snext;
2681
2682 /*
2683 * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
2684 */
2685 sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET));
2686 sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001);
2687 sappend(s, sjset_radiotap_tsft_present);
2688 sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present;
2689
2690 /*
2691 * If IEEE80211_RADIOTAP_TSFT is set, the flags field is
2692 * at an offset of 16 from the beginning of the raw packet
2693 * data (8 bytes for the radiotap header and 8 bytes for
2694 * the TSFT field).
2695 *
2696 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2697 * is set.
2698 */
2699 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2700 s2->s.k = 16;
2701 sappend(s, s2);
2702 sjset_radiotap_tsft_present->s.jt = s2;
2703
2704 sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2705 sjset_tsft_datapad->s.k = 0x20;
2706 sappend(s, sjset_tsft_datapad);
2707
2708 /*
2709 * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
2710 * at an offset of 8 from the beginning of the raw packet
2711 * data (8 bytes for the radiotap header).
2712 *
2713 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2714 * is set.
2715 */
2716 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2717 s2->s.k = 8;
2718 sappend(s, s2);
2719 sjset_radiotap_tsft_present->s.jf = s2;
2720
2721 sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2722 sjset_notsft_datapad->s.k = 0x20;
2723 sappend(s, sjset_notsft_datapad);
2724
2725 /*
2726 * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
2727 * set, round the length of the 802.11 header to
2728 * a multiple of 4. Do that by adding 3 and then
2729 * dividing by and multiplying by 4, which we do by
2730 * ANDing with ~3.
2731 */
2732 s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM);
2733 s_roundup->s.k = cstate->off_linkpl.reg;
2734 sappend(s, s_roundup);
2735 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2736 s2->s.k = 3;
2737 sappend(s, s2);
2738 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM);
2739 s2->s.k = ~3;
2740 sappend(s, s2);
2741 s2 = new_stmt(cstate, BPF_ST);
2742 s2->s.k = cstate->off_linkpl.reg;
2743 sappend(s, s2);
2744
2745 sjset_tsft_datapad->s.jt = s_roundup;
2746 sjset_tsft_datapad->s.jf = snext;
2747 sjset_notsft_datapad->s.jt = s_roundup;
2748 sjset_notsft_datapad->s.jf = snext;
2749 } else
2750 sjset_qos->s.jf = snext;
2751
2752 return s;
2753 }
2754
2755 static void
insert_compute_vloffsets(compiler_state_t * cstate,struct block * b)2756 insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
2757 {
2758 struct slist *s;
2759
2760 /* There is an implicit dependency between the link
2761 * payload and link header since the payload computation
2762 * includes the variable part of the header. Therefore,
2763 * if nobody else has allocated a register for the link
2764 * header and we need it, do it now. */
2765 if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable &&
2766 cstate->off_linkhdr.reg == -1)
2767 cstate->off_linkhdr.reg = alloc_reg(cstate);
2768
2769 /*
2770 * For link-layer types that have a variable-length header
2771 * preceding the link-layer header, generate code to load
2772 * the offset of the link-layer header into the register
2773 * assigned to that offset, if any.
2774 *
2775 * XXX - this, and the next switch statement, won't handle
2776 * encapsulation of 802.11 or 802.11+radio information in
2777 * some other protocol stack. That's significantly more
2778 * complicated.
2779 */
2780 switch (cstate->outermostlinktype) {
2781
2782 case DLT_PRISM_HEADER:
2783 s = gen_load_prism_llprefixlen(cstate);
2784 break;
2785
2786 case DLT_IEEE802_11_RADIO_AVS:
2787 s = gen_load_avs_llprefixlen(cstate);
2788 break;
2789
2790 case DLT_IEEE802_11_RADIO:
2791 s = gen_load_radiotap_llprefixlen(cstate);
2792 break;
2793
2794 case DLT_PPI:
2795 s = gen_load_ppi_llprefixlen(cstate);
2796 break;
2797
2798 default:
2799 s = NULL;
2800 break;
2801 }
2802
2803 /*
2804 * For link-layer types that have a variable-length link-layer
2805 * header, generate code to load the offset of the link-layer
2806 * payload into the register assigned to that offset, if any.
2807 */
2808 switch (cstate->outermostlinktype) {
2809
2810 case DLT_IEEE802_11:
2811 case DLT_PRISM_HEADER:
2812 case DLT_IEEE802_11_RADIO_AVS:
2813 case DLT_IEEE802_11_RADIO:
2814 case DLT_PPI:
2815 s = gen_load_802_11_header_len(cstate, s, b->stmts);
2816 break;
2817 }
2818
2819 /*
2820 * If there there is no initialization yet and we need variable
2821 * length offsets for VLAN, initialize them to zero
2822 */
2823 if (s == NULL && cstate->is_vlan_vloffset) {
2824 struct slist *s2;
2825
2826 if (cstate->off_linkpl.reg == -1)
2827 cstate->off_linkpl.reg = alloc_reg(cstate);
2828 if (cstate->off_linktype.reg == -1)
2829 cstate->off_linktype.reg = alloc_reg(cstate);
2830
2831 s = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2832 s->s.k = 0;
2833 s2 = new_stmt(cstate, BPF_ST);
2834 s2->s.k = cstate->off_linkpl.reg;
2835 sappend(s, s2);
2836 s2 = new_stmt(cstate, BPF_ST);
2837 s2->s.k = cstate->off_linktype.reg;
2838 sappend(s, s2);
2839 }
2840
2841 /*
2842 * If we have any offset-loading code, append all the
2843 * existing statements in the block to those statements,
2844 * and make the resulting list the list of statements
2845 * for the block.
2846 */
2847 if (s != NULL) {
2848 sappend(s, b->stmts);
2849 b->stmts = s;
2850 }
2851 }
2852
2853 static struct block *
gen_ppi_dlt_check(compiler_state_t * cstate)2854 gen_ppi_dlt_check(compiler_state_t *cstate)
2855 {
2856 struct slist *s_load_dlt;
2857 struct block *b;
2858
2859 if (cstate->linktype == DLT_PPI)
2860 {
2861 /* Create the statements that check for the DLT
2862 */
2863 s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2864 s_load_dlt->s.k = 4;
2865
2866 b = new_block(cstate, JMP(BPF_JEQ));
2867
2868 b->stmts = s_load_dlt;
2869 b->s.k = SWAPLONG(DLT_IEEE802_11);
2870 }
2871 else
2872 {
2873 b = NULL;
2874 }
2875
2876 return b;
2877 }
2878
2879 /*
2880 * Take an absolute offset, and:
2881 *
2882 * if it has no variable part, return NULL;
2883 *
2884 * if it has a variable part, generate code to load the register
2885 * containing that variable part into the X register, returning
2886 * a pointer to that code - if no register for that offset has
2887 * been allocated, allocate it first.
2888 *
2889 * (The code to set that register will be generated later, but will
2890 * be placed earlier in the code sequence.)
2891 */
2892 static struct slist *
gen_abs_offset_varpart(compiler_state_t * cstate,bpf_abs_offset * off)2893 gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off)
2894 {
2895 struct slist *s;
2896
2897 if (off->is_variable) {
2898 if (off->reg == -1) {
2899 /*
2900 * We haven't yet assigned a register for the
2901 * variable part of the offset of the link-layer
2902 * header; allocate one.
2903 */
2904 off->reg = alloc_reg(cstate);
2905 }
2906
2907 /*
2908 * Load the register containing the variable part of the
2909 * offset of the link-layer header into the X register.
2910 */
2911 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
2912 s->s.k = off->reg;
2913 return s;
2914 } else {
2915 /*
2916 * That offset isn't variable, there's no variable part,
2917 * so we don't need to generate any code.
2918 */
2919 return NULL;
2920 }
2921 }
2922
2923 /*
2924 * Map an Ethernet type to the equivalent PPP type.
2925 */
2926 static int
ethertype_to_ppptype(int proto)2927 ethertype_to_ppptype(int proto)
2928 {
2929 switch (proto) {
2930
2931 case ETHERTYPE_IP:
2932 proto = PPP_IP;
2933 break;
2934
2935 case ETHERTYPE_IPV6:
2936 proto = PPP_IPV6;
2937 break;
2938
2939 case ETHERTYPE_DN:
2940 proto = PPP_DECNET;
2941 break;
2942
2943 case ETHERTYPE_ATALK:
2944 proto = PPP_APPLE;
2945 break;
2946
2947 case ETHERTYPE_NS:
2948 proto = PPP_NS;
2949 break;
2950
2951 case LLCSAP_ISONS:
2952 proto = PPP_OSI;
2953 break;
2954
2955 case LLCSAP_8021D:
2956 /*
2957 * I'm assuming the "Bridging PDU"s that go
2958 * over PPP are Spanning Tree Protocol
2959 * Bridging PDUs.
2960 */
2961 proto = PPP_BRPDU;
2962 break;
2963
2964 case LLCSAP_IPX:
2965 proto = PPP_IPX;
2966 break;
2967 }
2968 return (proto);
2969 }
2970
2971 /*
2972 * Generate any tests that, for encapsulation of a link-layer packet
2973 * inside another protocol stack, need to be done to check for those
2974 * link-layer packets (and that haven't already been done by a check
2975 * for that encapsulation).
2976 */
2977 static struct block *
gen_prevlinkhdr_check(compiler_state_t * cstate)2978 gen_prevlinkhdr_check(compiler_state_t *cstate)
2979 {
2980 struct block *b0;
2981
2982 if (cstate->is_geneve)
2983 return gen_geneve_ll_check(cstate);
2984
2985 switch (cstate->prevlinktype) {
2986
2987 case DLT_SUNATM:
2988 /*
2989 * This is LANE-encapsulated Ethernet; check that the LANE
2990 * packet doesn't begin with an LE Control marker, i.e.
2991 * that it's data, not a control message.
2992 *
2993 * (We've already generated a test for LANE.)
2994 */
2995 b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00);
2996 gen_not(b0);
2997 return b0;
2998
2999 default:
3000 /*
3001 * No such tests are necessary.
3002 */
3003 return NULL;
3004 }
3005 /*NOTREACHED*/
3006 }
3007
3008 /*
3009 * The three different values we should check for when checking for an
3010 * IPv6 packet with DLT_NULL.
3011 */
3012 #define BSD_AFNUM_INET6_BSD 24 /* NetBSD, OpenBSD, BSD/OS, Npcap */
3013 #define BSD_AFNUM_INET6_FREEBSD 28 /* FreeBSD */
3014 #define BSD_AFNUM_INET6_DARWIN 30 /* macOS, iOS, other Darwin-based OSes */
3015
3016 /*
3017 * Generate code to match a particular packet type by matching the
3018 * link-layer type field or fields in the 802.2 LLC header.
3019 *
3020 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3021 * value, if <= ETHERMTU.
3022 */
3023 static struct block *
gen_linktype(compiler_state_t * cstate,int proto)3024 gen_linktype(compiler_state_t *cstate, int proto)
3025 {
3026 struct block *b0, *b1, *b2;
3027 const char *description;
3028
3029 /* are we checking MPLS-encapsulated packets? */
3030 if (cstate->label_stack_depth > 0) {
3031 switch (proto) {
3032 case ETHERTYPE_IP:
3033 case PPP_IP:
3034 /* FIXME add other L3 proto IDs */
3035 return gen_mpls_linktype(cstate, Q_IP);
3036
3037 case ETHERTYPE_IPV6:
3038 case PPP_IPV6:
3039 /* FIXME add other L3 proto IDs */
3040 return gen_mpls_linktype(cstate, Q_IPV6);
3041
3042 default:
3043 bpf_error(cstate, "unsupported protocol over mpls");
3044 /* NOTREACHED */
3045 }
3046 }
3047
3048 switch (cstate->linktype) {
3049
3050 case DLT_EN10MB:
3051 case DLT_NETANALYZER:
3052 case DLT_NETANALYZER_TRANSPARENT:
3053 /* Geneve has an EtherType regardless of whether there is an
3054 * L2 header. */
3055 if (!cstate->is_geneve)
3056 b0 = gen_prevlinkhdr_check(cstate);
3057 else
3058 b0 = NULL;
3059
3060 b1 = gen_ether_linktype(cstate, proto);
3061 if (b0 != NULL)
3062 gen_and(b0, b1);
3063 return b1;
3064 /*NOTREACHED*/
3065 break;
3066
3067 case DLT_C_HDLC:
3068 switch (proto) {
3069
3070 case LLCSAP_ISONS:
3071 proto = (proto << 8 | LLCSAP_ISONS);
3072 /* fall through */
3073
3074 default:
3075 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3076 /*NOTREACHED*/
3077 break;
3078 }
3079 break;
3080
3081 case DLT_IEEE802_11:
3082 case DLT_PRISM_HEADER:
3083 case DLT_IEEE802_11_RADIO_AVS:
3084 case DLT_IEEE802_11_RADIO:
3085 case DLT_PPI:
3086 /*
3087 * Check that we have a data frame.
3088 */
3089 b0 = gen_check_802_11_data_frame(cstate);
3090
3091 /*
3092 * Now check for the specified link-layer type.
3093 */
3094 b1 = gen_llc_linktype(cstate, proto);
3095 gen_and(b0, b1);
3096 return b1;
3097 /*NOTREACHED*/
3098 break;
3099
3100 case DLT_FDDI:
3101 /*
3102 * XXX - check for LLC frames.
3103 */
3104 return gen_llc_linktype(cstate, proto);
3105 /*NOTREACHED*/
3106 break;
3107
3108 case DLT_IEEE802:
3109 /*
3110 * XXX - check for LLC PDUs, as per IEEE 802.5.
3111 */
3112 return gen_llc_linktype(cstate, proto);
3113 /*NOTREACHED*/
3114 break;
3115
3116 case DLT_ATM_RFC1483:
3117 case DLT_ATM_CLIP:
3118 case DLT_IP_OVER_FC:
3119 return gen_llc_linktype(cstate, proto);
3120 /*NOTREACHED*/
3121 break;
3122
3123 case DLT_SUNATM:
3124 /*
3125 * Check for an LLC-encapsulated version of this protocol;
3126 * if we were checking for LANE, linktype would no longer
3127 * be DLT_SUNATM.
3128 *
3129 * Check for LLC encapsulation and then check the protocol.
3130 */
3131 b0 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
3132 b1 = gen_llc_linktype(cstate, proto);
3133 gen_and(b0, b1);
3134 return b1;
3135 /*NOTREACHED*/
3136 break;
3137
3138 case DLT_LINUX_SLL:
3139 return gen_linux_sll_linktype(cstate, proto);
3140 /*NOTREACHED*/
3141 break;
3142
3143 case DLT_SLIP:
3144 case DLT_SLIP_BSDOS:
3145 case DLT_RAW:
3146 /*
3147 * These types don't provide any type field; packets
3148 * are always IPv4 or IPv6.
3149 *
3150 * XXX - for IPv4, check for a version number of 4, and,
3151 * for IPv6, check for a version number of 6?
3152 */
3153 switch (proto) {
3154
3155 case ETHERTYPE_IP:
3156 /* Check for a version number of 4. */
3157 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0);
3158
3159 case ETHERTYPE_IPV6:
3160 /* Check for a version number of 6. */
3161 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0);
3162
3163 default:
3164 return gen_false(cstate); /* always false */
3165 }
3166 /*NOTREACHED*/
3167 break;
3168
3169 case DLT_IPV4:
3170 /*
3171 * Raw IPv4, so no type field.
3172 */
3173 if (proto == ETHERTYPE_IP)
3174 return gen_true(cstate); /* always true */
3175
3176 /* Checking for something other than IPv4; always false */
3177 return gen_false(cstate);
3178 /*NOTREACHED*/
3179 break;
3180
3181 case DLT_IPV6:
3182 /*
3183 * Raw IPv6, so no type field.
3184 */
3185 if (proto == ETHERTYPE_IPV6)
3186 return gen_true(cstate); /* always true */
3187
3188 /* Checking for something other than IPv6; always false */
3189 return gen_false(cstate);
3190 /*NOTREACHED*/
3191 break;
3192
3193 case DLT_PPP:
3194 case DLT_PPP_PPPD:
3195 case DLT_PPP_SERIAL:
3196 case DLT_PPP_ETHER:
3197 /*
3198 * We use Ethernet protocol types inside libpcap;
3199 * map them to the corresponding PPP protocol types.
3200 */
3201 proto = ethertype_to_ppptype(proto);
3202 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3203 /*NOTREACHED*/
3204 break;
3205
3206 case DLT_PPP_BSDOS:
3207 /*
3208 * We use Ethernet protocol types inside libpcap;
3209 * map them to the corresponding PPP protocol types.
3210 */
3211 switch (proto) {
3212
3213 case ETHERTYPE_IP:
3214 /*
3215 * Also check for Van Jacobson-compressed IP.
3216 * XXX - do this for other forms of PPP?
3217 */
3218 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP);
3219 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC);
3220 gen_or(b0, b1);
3221 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC);
3222 gen_or(b1, b0);
3223 return b0;
3224
3225 default:
3226 proto = ethertype_to_ppptype(proto);
3227 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
3228 (bpf_int32)proto);
3229 }
3230 /*NOTREACHED*/
3231 break;
3232
3233 case DLT_NULL:
3234 case DLT_LOOP:
3235 case DLT_ENC:
3236 switch (proto) {
3237
3238 case ETHERTYPE_IP:
3239 return (gen_loopback_linktype(cstate, AF_INET));
3240
3241 case ETHERTYPE_IPV6:
3242 /*
3243 * AF_ values may, unfortunately, be platform-
3244 * dependent; AF_INET isn't, because everybody
3245 * used 4.2BSD's value, but AF_INET6 is, because
3246 * 4.2BSD didn't have a value for it (given that
3247 * IPv6 didn't exist back in the early 1980's),
3248 * and they all picked their own values.
3249 *
3250 * This means that, if we're reading from a
3251 * savefile, we need to check for all the
3252 * possible values.
3253 *
3254 * If we're doing a live capture, we only need
3255 * to check for this platform's value; however,
3256 * Npcap uses 24, which isn't Windows's AF_INET6
3257 * value. (Given the multiple different values,
3258 * programs that read pcap files shouldn't be
3259 * checking for their platform's AF_INET6 value
3260 * anyway, they should check for all of the
3261 * possible values. and they might as well do
3262 * that even for live captures.)
3263 */
3264 if (cstate->bpf_pcap->rfile != NULL) {
3265 /*
3266 * Savefile - check for all three
3267 * possible IPv6 values.
3268 */
3269 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD);
3270 b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD);
3271 gen_or(b0, b1);
3272 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN);
3273 gen_or(b0, b1);
3274 return (b1);
3275 } else {
3276 /*
3277 * Live capture, so we only need to
3278 * check for the value used on this
3279 * platform.
3280 */
3281 #ifdef _WIN32
3282 /*
3283 * Npcap doesn't use Windows's AF_INET6,
3284 * as that collides with AF_IPX on
3285 * some BSDs (both have the value 23).
3286 * Instead, it uses 24.
3287 */
3288 return (gen_loopback_linktype(cstate, 24));
3289 #else /* _WIN32 */
3290 #ifdef AF_INET6
3291 return (gen_loopback_linktype(cstate, AF_INET6));
3292 #else /* AF_INET6 */
3293 /*
3294 * I guess this platform doesn't support
3295 * IPv6, so we just reject all packets.
3296 */
3297 return gen_false(cstate);
3298 #endif /* AF_INET6 */
3299 #endif /* _WIN32 */
3300 }
3301
3302 default:
3303 /*
3304 * Not a type on which we support filtering.
3305 * XXX - support those that have AF_ values
3306 * #defined on this platform, at least?
3307 */
3308 return gen_false(cstate);
3309 }
3310
3311 #ifdef HAVE_NET_PFVAR_H
3312 case DLT_PFLOG:
3313 /*
3314 * af field is host byte order in contrast to the rest of
3315 * the packet.
3316 */
3317 if (proto == ETHERTYPE_IP)
3318 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3319 BPF_B, (bpf_int32)AF_INET));
3320 else if (proto == ETHERTYPE_IPV6)
3321 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3322 BPF_B, (bpf_int32)AF_INET6));
3323 else
3324 return gen_false(cstate);
3325 /*NOTREACHED*/
3326 break;
3327 #endif /* HAVE_NET_PFVAR_H */
3328
3329 case DLT_ARCNET:
3330 case DLT_ARCNET_LINUX:
3331 /*
3332 * XXX should we check for first fragment if the protocol
3333 * uses PHDS?
3334 */
3335 switch (proto) {
3336
3337 default:
3338 return gen_false(cstate);
3339
3340 case ETHERTYPE_IPV6:
3341 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3342 (bpf_int32)ARCTYPE_INET6));
3343
3344 case ETHERTYPE_IP:
3345 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3346 (bpf_int32)ARCTYPE_IP);
3347 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3348 (bpf_int32)ARCTYPE_IP_OLD);
3349 gen_or(b0, b1);
3350 return (b1);
3351
3352 case ETHERTYPE_ARP:
3353 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3354 (bpf_int32)ARCTYPE_ARP);
3355 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3356 (bpf_int32)ARCTYPE_ARP_OLD);
3357 gen_or(b0, b1);
3358 return (b1);
3359
3360 case ETHERTYPE_REVARP:
3361 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3362 (bpf_int32)ARCTYPE_REVARP));
3363
3364 case ETHERTYPE_ATALK:
3365 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3366 (bpf_int32)ARCTYPE_ATALK));
3367 }
3368 /*NOTREACHED*/
3369 break;
3370
3371 case DLT_LTALK:
3372 switch (proto) {
3373 case ETHERTYPE_ATALK:
3374 return gen_true(cstate);
3375 default:
3376 return gen_false(cstate);
3377 }
3378 /*NOTREACHED*/
3379 break;
3380
3381 case DLT_FRELAY:
3382 /*
3383 * XXX - assumes a 2-byte Frame Relay header with
3384 * DLCI and flags. What if the address is longer?
3385 */
3386 switch (proto) {
3387
3388 case ETHERTYPE_IP:
3389 /*
3390 * Check for the special NLPID for IP.
3391 */
3392 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc);
3393
3394 case ETHERTYPE_IPV6:
3395 /*
3396 * Check for the special NLPID for IPv6.
3397 */
3398 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e);
3399
3400 case LLCSAP_ISONS:
3401 /*
3402 * Check for several OSI protocols.
3403 *
3404 * Frame Relay packets typically have an OSI
3405 * NLPID at the beginning; we check for each
3406 * of them.
3407 *
3408 * What we check for is the NLPID and a frame
3409 * control field of UI, i.e. 0x03 followed
3410 * by the NLPID.
3411 */
3412 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
3413 b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
3414 b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
3415 gen_or(b1, b2);
3416 gen_or(b0, b2);
3417 return b2;
3418
3419 default:
3420 return gen_false(cstate);
3421 }
3422 /*NOTREACHED*/
3423 break;
3424
3425 case DLT_MFR:
3426 bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented");
3427
3428 case DLT_JUNIPER_MFR:
3429 case DLT_JUNIPER_MLFR:
3430 case DLT_JUNIPER_MLPPP:
3431 case DLT_JUNIPER_ATM1:
3432 case DLT_JUNIPER_ATM2:
3433 case DLT_JUNIPER_PPPOE:
3434 case DLT_JUNIPER_PPPOE_ATM:
3435 case DLT_JUNIPER_GGSN:
3436 case DLT_JUNIPER_ES:
3437 case DLT_JUNIPER_MONITOR:
3438 case DLT_JUNIPER_SERVICES:
3439 case DLT_JUNIPER_ETHER:
3440 case DLT_JUNIPER_PPP:
3441 case DLT_JUNIPER_FRELAY:
3442 case DLT_JUNIPER_CHDLC:
3443 case DLT_JUNIPER_VP:
3444 case DLT_JUNIPER_ST:
3445 case DLT_JUNIPER_ISM:
3446 case DLT_JUNIPER_VS:
3447 case DLT_JUNIPER_SRX_E2E:
3448 case DLT_JUNIPER_FIBRECHANNEL:
3449 case DLT_JUNIPER_ATM_CEMIC:
3450
3451 /* just lets verify the magic number for now -
3452 * on ATM we may have up to 6 different encapsulations on the wire
3453 * and need a lot of heuristics to figure out that the payload
3454 * might be;
3455 *
3456 * FIXME encapsulation specific BPF_ filters
3457 */
3458 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
3459
3460 case DLT_BACNET_MS_TP:
3461 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000);
3462
3463 case DLT_IPNET:
3464 return gen_ipnet_linktype(cstate, proto);
3465
3466 case DLT_LINUX_IRDA:
3467 bpf_error(cstate, "IrDA link-layer type filtering not implemented");
3468
3469 case DLT_DOCSIS:
3470 bpf_error(cstate, "DOCSIS link-layer type filtering not implemented");
3471
3472 case DLT_MTP2:
3473 case DLT_MTP2_WITH_PHDR:
3474 bpf_error(cstate, "MTP2 link-layer type filtering not implemented");
3475
3476 case DLT_ERF:
3477 bpf_error(cstate, "ERF link-layer type filtering not implemented");
3478
3479 case DLT_PFSYNC:
3480 bpf_error(cstate, "PFSYNC link-layer type filtering not implemented");
3481
3482 case DLT_LINUX_LAPD:
3483 bpf_error(cstate, "LAPD link-layer type filtering not implemented");
3484
3485 case DLT_USB_FREEBSD:
3486 case DLT_USB_LINUX:
3487 case DLT_USB_LINUX_MMAPPED:
3488 case DLT_USBPCAP:
3489 bpf_error(cstate, "USB link-layer type filtering not implemented");
3490
3491 case DLT_BLUETOOTH_HCI_H4:
3492 case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
3493 bpf_error(cstate, "Bluetooth link-layer type filtering not implemented");
3494
3495 case DLT_CAN20B:
3496 case DLT_CAN_SOCKETCAN:
3497 bpf_error(cstate, "CAN link-layer type filtering not implemented");
3498
3499 case DLT_IEEE802_15_4:
3500 case DLT_IEEE802_15_4_LINUX:
3501 case DLT_IEEE802_15_4_NONASK_PHY:
3502 case DLT_IEEE802_15_4_NOFCS:
3503 bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented");
3504
3505 case DLT_IEEE802_16_MAC_CPS_RADIO:
3506 bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented");
3507
3508 case DLT_SITA:
3509 bpf_error(cstate, "SITA link-layer type filtering not implemented");
3510
3511 case DLT_RAIF1:
3512 bpf_error(cstate, "RAIF1 link-layer type filtering not implemented");
3513
3514 case DLT_IPMB:
3515 bpf_error(cstate, "IPMB link-layer type filtering not implemented");
3516
3517 case DLT_AX25_KISS:
3518 bpf_error(cstate, "AX.25 link-layer type filtering not implemented");
3519
3520 case DLT_NFLOG:
3521 /* Using the fixed-size NFLOG header it is possible to tell only
3522 * the address family of the packet, other meaningful data is
3523 * either missing or behind TLVs.
3524 */
3525 bpf_error(cstate, "NFLOG link-layer type filtering not implemented");
3526
3527 default:
3528 /*
3529 * Does this link-layer header type have a field
3530 * indicating the type of the next protocol? If
3531 * so, off_linktype.constant_part will be the offset of that
3532 * field in the packet; if not, it will be OFFSET_NOT_SET.
3533 */
3534 if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) {
3535 /*
3536 * Yes; assume it's an Ethernet type. (If
3537 * it's not, it needs to be handled specially
3538 * above.)
3539 */
3540 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3541 } else {
3542 /*
3543 * No; report an error.
3544 */
3545 description = pcap_datalink_val_to_description(cstate->linktype);
3546 if (description != NULL) {
3547 bpf_error(cstate, "%s link-layer type filtering not implemented",
3548 description);
3549 } else {
3550 bpf_error(cstate, "DLT %u link-layer type filtering not implemented",
3551 cstate->linktype);
3552 }
3553 }
3554 break;
3555 }
3556 }
3557
3558 /*
3559 * Check for an LLC SNAP packet with a given organization code and
3560 * protocol type; we check the entire contents of the 802.2 LLC and
3561 * snap headers, checking for DSAP and SSAP of SNAP and a control
3562 * field of 0x03 in the LLC header, and for the specified organization
3563 * code and protocol type in the SNAP header.
3564 */
3565 static struct block *
gen_snap(compiler_state_t * cstate,bpf_u_int32 orgcode,bpf_u_int32 ptype)3566 gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype)
3567 {
3568 u_char snapblock[8];
3569
3570 snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
3571 snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
3572 snapblock[2] = 0x03; /* control = UI */
3573 snapblock[3] = (u_char)(orgcode >> 16); /* upper 8 bits of organization code */
3574 snapblock[4] = (u_char)(orgcode >> 8); /* middle 8 bits of organization code */
3575 snapblock[5] = (u_char)(orgcode >> 0); /* lower 8 bits of organization code */
3576 snapblock[6] = (u_char)(ptype >> 8); /* upper 8 bits of protocol type */
3577 snapblock[7] = (u_char)(ptype >> 0); /* lower 8 bits of protocol type */
3578 return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock);
3579 }
3580
3581 /*
3582 * Generate code to match frames with an LLC header.
3583 */
3584 struct block *
gen_llc(compiler_state_t * cstate)3585 gen_llc(compiler_state_t *cstate)
3586 {
3587 struct block *b0, *b1;
3588
3589 switch (cstate->linktype) {
3590
3591 case DLT_EN10MB:
3592 /*
3593 * We check for an Ethernet type field less than
3594 * 1500, which means it's an 802.3 length field.
3595 */
3596 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
3597 gen_not(b0);
3598
3599 /*
3600 * Now check for the purported DSAP and SSAP not being
3601 * 0xFF, to rule out NetWare-over-802.3.
3602 */
3603 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
3604 gen_not(b1);
3605 gen_and(b0, b1);
3606 return b1;
3607
3608 case DLT_SUNATM:
3609 /*
3610 * We check for LLC traffic.
3611 */
3612 b0 = gen_atmtype_abbrev(cstate, A_LLC);
3613 return b0;
3614
3615 case DLT_IEEE802: /* Token Ring */
3616 /*
3617 * XXX - check for LLC frames.
3618 */
3619 return gen_true(cstate);
3620
3621 case DLT_FDDI:
3622 /*
3623 * XXX - check for LLC frames.
3624 */
3625 return gen_true(cstate);
3626
3627 case DLT_ATM_RFC1483:
3628 /*
3629 * For LLC encapsulation, these are defined to have an
3630 * 802.2 LLC header.
3631 *
3632 * For VC encapsulation, they don't, but there's no
3633 * way to check for that; the protocol used on the VC
3634 * is negotiated out of band.
3635 */
3636 return gen_true(cstate);
3637
3638 case DLT_IEEE802_11:
3639 case DLT_PRISM_HEADER:
3640 case DLT_IEEE802_11_RADIO:
3641 case DLT_IEEE802_11_RADIO_AVS:
3642 case DLT_PPI:
3643 /*
3644 * Check that we have a data frame.
3645 */
3646 b0 = gen_check_802_11_data_frame(cstate);
3647 return b0;
3648
3649 default:
3650 bpf_error(cstate, "'llc' not supported for linktype %d", cstate->linktype);
3651 /* NOTREACHED */
3652 }
3653 }
3654
3655 struct block *
gen_llc_i(compiler_state_t * cstate)3656 gen_llc_i(compiler_state_t *cstate)
3657 {
3658 struct block *b0, *b1;
3659 struct slist *s;
3660
3661 /*
3662 * Check whether this is an LLC frame.
3663 */
3664 b0 = gen_llc(cstate);
3665
3666 /*
3667 * Load the control byte and test the low-order bit; it must
3668 * be clear for I frames.
3669 */
3670 s = gen_load_a(cstate, OR_LLC, 2, BPF_B);
3671 b1 = new_block(cstate, JMP(BPF_JSET));
3672 b1->s.k = 0x01;
3673 b1->stmts = s;
3674 gen_not(b1);
3675 gen_and(b0, b1);
3676 return b1;
3677 }
3678
3679 struct block *
gen_llc_s(compiler_state_t * cstate)3680 gen_llc_s(compiler_state_t *cstate)
3681 {
3682 struct block *b0, *b1;
3683
3684 /*
3685 * Check whether this is an LLC frame.
3686 */
3687 b0 = gen_llc(cstate);
3688
3689 /*
3690 * Now compare the low-order 2 bit of the control byte against
3691 * the appropriate value for S frames.
3692 */
3693 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03);
3694 gen_and(b0, b1);
3695 return b1;
3696 }
3697
3698 struct block *
gen_llc_u(compiler_state_t * cstate)3699 gen_llc_u(compiler_state_t *cstate)
3700 {
3701 struct block *b0, *b1;
3702
3703 /*
3704 * Check whether this is an LLC frame.
3705 */
3706 b0 = gen_llc(cstate);
3707
3708 /*
3709 * Now compare the low-order 2 bit of the control byte against
3710 * the appropriate value for U frames.
3711 */
3712 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03);
3713 gen_and(b0, b1);
3714 return b1;
3715 }
3716
3717 struct block *
gen_llc_s_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3718 gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3719 {
3720 struct block *b0, *b1;
3721
3722 /*
3723 * Check whether this is an LLC frame.
3724 */
3725 b0 = gen_llc(cstate);
3726
3727 /*
3728 * Now check for an S frame with the appropriate type.
3729 */
3730 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK);
3731 gen_and(b0, b1);
3732 return b1;
3733 }
3734
3735 struct block *
gen_llc_u_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3736 gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3737 {
3738 struct block *b0, *b1;
3739
3740 /*
3741 * Check whether this is an LLC frame.
3742 */
3743 b0 = gen_llc(cstate);
3744
3745 /*
3746 * Now check for a U frame with the appropriate type.
3747 */
3748 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK);
3749 gen_and(b0, b1);
3750 return b1;
3751 }
3752
3753 /*
3754 * Generate code to match a particular packet type, for link-layer types
3755 * using 802.2 LLC headers.
3756 *
3757 * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
3758 * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
3759 *
3760 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3761 * value, if <= ETHERMTU. We use that to determine whether to
3762 * match the DSAP or both DSAP and LSAP or to check the OUI and
3763 * protocol ID in a SNAP header.
3764 */
3765 static struct block *
gen_llc_linktype(compiler_state_t * cstate,int proto)3766 gen_llc_linktype(compiler_state_t *cstate, int proto)
3767 {
3768 /*
3769 * XXX - handle token-ring variable-length header.
3770 */
3771 switch (proto) {
3772
3773 case LLCSAP_IP:
3774 case LLCSAP_ISONS:
3775 case LLCSAP_NETBEUI:
3776 /*
3777 * XXX - should we check both the DSAP and the
3778 * SSAP, like this, or should we check just the
3779 * DSAP, as we do for other SAP values?
3780 */
3781 return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32)
3782 ((proto << 8) | proto));
3783
3784 case LLCSAP_IPX:
3785 /*
3786 * XXX - are there ever SNAP frames for IPX on
3787 * non-Ethernet 802.x networks?
3788 */
3789 return gen_cmp(cstate, OR_LLC, 0, BPF_B,
3790 (bpf_int32)LLCSAP_IPX);
3791
3792 case ETHERTYPE_ATALK:
3793 /*
3794 * 802.2-encapsulated ETHERTYPE_ATALK packets are
3795 * SNAP packets with an organization code of
3796 * 0x080007 (Apple, for Appletalk) and a protocol
3797 * type of ETHERTYPE_ATALK (Appletalk).
3798 *
3799 * XXX - check for an organization code of
3800 * encapsulated Ethernet as well?
3801 */
3802 return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
3803
3804 default:
3805 /*
3806 * XXX - we don't have to check for IPX 802.3
3807 * here, but should we check for the IPX Ethertype?
3808 */
3809 if (proto <= ETHERMTU) {
3810 /*
3811 * This is an LLC SAP value, so check
3812 * the DSAP.
3813 */
3814 return gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)proto);
3815 } else {
3816 /*
3817 * This is an Ethernet type; we assume that it's
3818 * unlikely that it'll appear in the right place
3819 * at random, and therefore check only the
3820 * location that would hold the Ethernet type
3821 * in a SNAP frame with an organization code of
3822 * 0x000000 (encapsulated Ethernet).
3823 *
3824 * XXX - if we were to check for the SNAP DSAP and
3825 * LSAP, as per XXX, and were also to check for an
3826 * organization code of 0x000000 (encapsulated
3827 * Ethernet), we'd do
3828 *
3829 * return gen_snap(cstate, 0x000000, proto);
3830 *
3831 * here; for now, we don't, as per the above.
3832 * I don't know whether it's worth the extra CPU
3833 * time to do the right check or not.
3834 */
3835 return gen_cmp(cstate, OR_LLC, 6, BPF_H, (bpf_int32)proto);
3836 }
3837 }
3838 }
3839
3840 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)3841 gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
3842 int dir, int proto, u_int src_off, u_int dst_off)
3843 {
3844 struct block *b0, *b1;
3845 u_int offset;
3846
3847 switch (dir) {
3848
3849 case Q_SRC:
3850 offset = src_off;
3851 break;
3852
3853 case Q_DST:
3854 offset = dst_off;
3855 break;
3856
3857 case Q_AND:
3858 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3859 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3860 gen_and(b0, b1);
3861 return b1;
3862
3863 case Q_OR:
3864 case Q_DEFAULT:
3865 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3866 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3867 gen_or(b0, b1);
3868 return b1;
3869
3870 case Q_ADDR1:
3871 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3872 break;
3873
3874 case Q_ADDR2:
3875 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3876 break;
3877
3878 case Q_ADDR3:
3879 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3880 break;
3881
3882 case Q_ADDR4:
3883 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3884 break;
3885
3886 case Q_RA:
3887 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3888 break;
3889
3890 case Q_TA:
3891 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3892 break;
3893
3894 default:
3895 abort();
3896 }
3897 b0 = gen_linktype(cstate, proto);
3898 b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, (bpf_int32)addr, mask);
3899 gen_and(b0, b1);
3900 return b1;
3901 }
3902
3903 #ifdef INET6
3904 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)3905 gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
3906 struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off)
3907 {
3908 struct block *b0, *b1;
3909 u_int offset;
3910 uint32_t *a, *m;
3911
3912 switch (dir) {
3913
3914 case Q_SRC:
3915 offset = src_off;
3916 break;
3917
3918 case Q_DST:
3919 offset = dst_off;
3920 break;
3921
3922 case Q_AND:
3923 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3924 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3925 gen_and(b0, b1);
3926 return b1;
3927
3928 case Q_OR:
3929 case Q_DEFAULT:
3930 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3931 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
3932 gen_or(b0, b1);
3933 return b1;
3934
3935 case Q_ADDR1:
3936 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3937 break;
3938
3939 case Q_ADDR2:
3940 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3941 break;
3942
3943 case Q_ADDR3:
3944 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3945 break;
3946
3947 case Q_ADDR4:
3948 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
3949 break;
3950
3951 case Q_RA:
3952 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3953 break;
3954
3955 case Q_TA:
3956 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
3957 break;
3958
3959 default:
3960 abort();
3961 }
3962 /* this order is important */
3963 a = (uint32_t *)addr;
3964 m = (uint32_t *)mask;
3965 b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
3966 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
3967 gen_and(b0, b1);
3968 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
3969 gen_and(b0, b1);
3970 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
3971 gen_and(b0, b1);
3972 b0 = gen_linktype(cstate, proto);
3973 gen_and(b0, b1);
3974 return b1;
3975 }
3976 #endif
3977
3978 static struct block *
gen_ehostop(compiler_state_t * cstate,const u_char * eaddr,int dir)3979 gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
3980 {
3981 register struct block *b0, *b1;
3982
3983 switch (dir) {
3984 case Q_SRC:
3985 return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
3986
3987 case Q_DST:
3988 return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
3989
3990 case Q_AND:
3991 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
3992 b1 = gen_ehostop(cstate, eaddr, Q_DST);
3993 gen_and(b0, b1);
3994 return b1;
3995
3996 case Q_DEFAULT:
3997 case Q_OR:
3998 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
3999 b1 = gen_ehostop(cstate, eaddr, Q_DST);
4000 gen_or(b0, b1);
4001 return b1;
4002
4003 case Q_ADDR1:
4004 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11 with 802.11 headers");
4005 break;
4006
4007 case Q_ADDR2:
4008 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11 with 802.11 headers");
4009 break;
4010
4011 case Q_ADDR3:
4012 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11 with 802.11 headers");
4013 break;
4014
4015 case Q_ADDR4:
4016 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11 with 802.11 headers");
4017 break;
4018
4019 case Q_RA:
4020 bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers");
4021 break;
4022
4023 case Q_TA:
4024 bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers");
4025 break;
4026 }
4027 abort();
4028 /* NOTREACHED */
4029 }
4030
4031 /*
4032 * Like gen_ehostop, but for DLT_FDDI
4033 */
4034 static struct block *
gen_fhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4035 gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4036 {
4037 struct block *b0, *b1;
4038
4039 switch (dir) {
4040 case Q_SRC:
4041 return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
4042
4043 case Q_DST:
4044 return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
4045
4046 case Q_AND:
4047 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4048 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4049 gen_and(b0, b1);
4050 return b1;
4051
4052 case Q_DEFAULT:
4053 case Q_OR:
4054 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4055 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4056 gen_or(b0, b1);
4057 return b1;
4058
4059 case Q_ADDR1:
4060 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4061 break;
4062
4063 case Q_ADDR2:
4064 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4065 break;
4066
4067 case Q_ADDR3:
4068 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4069 break;
4070
4071 case Q_ADDR4:
4072 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4073 break;
4074
4075 case Q_RA:
4076 bpf_error(cstate, "'ra' is only supported on 802.11");
4077 break;
4078
4079 case Q_TA:
4080 bpf_error(cstate, "'ta' is only supported on 802.11");
4081 break;
4082 }
4083 abort();
4084 /* NOTREACHED */
4085 }
4086
4087 /*
4088 * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
4089 */
4090 static struct block *
gen_thostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4091 gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4092 {
4093 register struct block *b0, *b1;
4094
4095 switch (dir) {
4096 case Q_SRC:
4097 return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
4098
4099 case Q_DST:
4100 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4101
4102 case Q_AND:
4103 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4104 b1 = gen_thostop(cstate, eaddr, Q_DST);
4105 gen_and(b0, b1);
4106 return b1;
4107
4108 case Q_DEFAULT:
4109 case Q_OR:
4110 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4111 b1 = gen_thostop(cstate, eaddr, Q_DST);
4112 gen_or(b0, b1);
4113 return b1;
4114
4115 case Q_ADDR1:
4116 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4117 break;
4118
4119 case Q_ADDR2:
4120 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4121 break;
4122
4123 case Q_ADDR3:
4124 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4125 break;
4126
4127 case Q_ADDR4:
4128 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4129 break;
4130
4131 case Q_RA:
4132 bpf_error(cstate, "'ra' is only supported on 802.11");
4133 break;
4134
4135 case Q_TA:
4136 bpf_error(cstate, "'ta' is only supported on 802.11");
4137 break;
4138 }
4139 abort();
4140 /* NOTREACHED */
4141 }
4142
4143 /*
4144 * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
4145 * various 802.11 + radio headers.
4146 */
4147 static struct block *
gen_wlanhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4148 gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4149 {
4150 register struct block *b0, *b1, *b2;
4151 register struct slist *s;
4152
4153 #ifdef ENABLE_WLAN_FILTERING_PATCH
4154 /*
4155 * TODO GV 20070613
4156 * We need to disable the optimizer because the optimizer is buggy
4157 * and wipes out some LD instructions generated by the below
4158 * code to validate the Frame Control bits
4159 */
4160 cstate->no_optimize = 1;
4161 #endif /* ENABLE_WLAN_FILTERING_PATCH */
4162
4163 switch (dir) {
4164 case Q_SRC:
4165 /*
4166 * Oh, yuk.
4167 *
4168 * For control frames, there is no SA.
4169 *
4170 * For management frames, SA is at an
4171 * offset of 10 from the beginning of
4172 * the packet.
4173 *
4174 * For data frames, SA is at an offset
4175 * of 10 from the beginning of the packet
4176 * if From DS is clear, at an offset of
4177 * 16 from the beginning of the packet
4178 * if From DS is set and To DS is clear,
4179 * and an offset of 24 from the beginning
4180 * of the packet if From DS is set and To DS
4181 * is set.
4182 */
4183
4184 /*
4185 * Generate the tests to be done for data frames
4186 * with From DS set.
4187 *
4188 * First, check for To DS set, i.e. check "link[1] & 0x01".
4189 */
4190 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4191 b1 = new_block(cstate, JMP(BPF_JSET));
4192 b1->s.k = 0x01; /* To DS */
4193 b1->stmts = s;
4194
4195 /*
4196 * If To DS is set, the SA is at 24.
4197 */
4198 b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4199 gen_and(b1, b0);
4200
4201 /*
4202 * Now, check for To DS not set, i.e. check
4203 * "!(link[1] & 0x01)".
4204 */
4205 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4206 b2 = new_block(cstate, JMP(BPF_JSET));
4207 b2->s.k = 0x01; /* To DS */
4208 b2->stmts = s;
4209 gen_not(b2);
4210
4211 /*
4212 * If To DS is not set, the SA is at 16.
4213 */
4214 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4215 gen_and(b2, b1);
4216
4217 /*
4218 * Now OR together the last two checks. That gives
4219 * the complete set of checks for data frames with
4220 * From DS set.
4221 */
4222 gen_or(b1, b0);
4223
4224 /*
4225 * Now check for From DS being set, and AND that with
4226 * the ORed-together checks.
4227 */
4228 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4229 b1 = new_block(cstate, JMP(BPF_JSET));
4230 b1->s.k = 0x02; /* From DS */
4231 b1->stmts = s;
4232 gen_and(b1, b0);
4233
4234 /*
4235 * Now check for data frames with From DS not set.
4236 */
4237 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4238 b2 = new_block(cstate, JMP(BPF_JSET));
4239 b2->s.k = 0x02; /* From DS */
4240 b2->stmts = s;
4241 gen_not(b2);
4242
4243 /*
4244 * If From DS isn't set, the SA is at 10.
4245 */
4246 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4247 gen_and(b2, b1);
4248
4249 /*
4250 * Now OR together the checks for data frames with
4251 * From DS not set and for data frames with From DS
4252 * set; that gives the checks done for data frames.
4253 */
4254 gen_or(b1, b0);
4255
4256 /*
4257 * Now check for a data frame.
4258 * I.e, check "link[0] & 0x08".
4259 */
4260 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4261 b1 = new_block(cstate, JMP(BPF_JSET));
4262 b1->s.k = 0x08;
4263 b1->stmts = s;
4264
4265 /*
4266 * AND that with the checks done for data frames.
4267 */
4268 gen_and(b1, b0);
4269
4270 /*
4271 * If the high-order bit of the type value is 0, this
4272 * is a management frame.
4273 * I.e, check "!(link[0] & 0x08)".
4274 */
4275 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4276 b2 = new_block(cstate, JMP(BPF_JSET));
4277 b2->s.k = 0x08;
4278 b2->stmts = s;
4279 gen_not(b2);
4280
4281 /*
4282 * For management frames, the SA is at 10.
4283 */
4284 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4285 gen_and(b2, b1);
4286
4287 /*
4288 * OR that with the checks done for data frames.
4289 * That gives the checks done for management and
4290 * data frames.
4291 */
4292 gen_or(b1, b0);
4293
4294 /*
4295 * If the low-order bit of the type value is 1,
4296 * this is either a control frame or a frame
4297 * with a reserved type, and thus not a
4298 * frame with an SA.
4299 *
4300 * I.e., check "!(link[0] & 0x04)".
4301 */
4302 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4303 b1 = new_block(cstate, JMP(BPF_JSET));
4304 b1->s.k = 0x04;
4305 b1->stmts = s;
4306 gen_not(b1);
4307
4308 /*
4309 * AND that with the checks for data and management
4310 * frames.
4311 */
4312 gen_and(b1, b0);
4313 return b0;
4314
4315 case Q_DST:
4316 /*
4317 * Oh, yuk.
4318 *
4319 * For control frames, there is no DA.
4320 *
4321 * For management frames, DA is at an
4322 * offset of 4 from the beginning of
4323 * the packet.
4324 *
4325 * For data frames, DA is at an offset
4326 * of 4 from the beginning of the packet
4327 * if To DS is clear and at an offset of
4328 * 16 from the beginning of the packet
4329 * if To DS is set.
4330 */
4331
4332 /*
4333 * Generate the tests to be done for data frames.
4334 *
4335 * First, check for To DS set, i.e. "link[1] & 0x01".
4336 */
4337 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4338 b1 = new_block(cstate, JMP(BPF_JSET));
4339 b1->s.k = 0x01; /* To DS */
4340 b1->stmts = s;
4341
4342 /*
4343 * If To DS is set, the DA is at 16.
4344 */
4345 b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4346 gen_and(b1, b0);
4347
4348 /*
4349 * Now, check for To DS not set, i.e. check
4350 * "!(link[1] & 0x01)".
4351 */
4352 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4353 b2 = new_block(cstate, JMP(BPF_JSET));
4354 b2->s.k = 0x01; /* To DS */
4355 b2->stmts = s;
4356 gen_not(b2);
4357
4358 /*
4359 * If To DS is not set, the DA is at 4.
4360 */
4361 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4362 gen_and(b2, b1);
4363
4364 /*
4365 * Now OR together the last two checks. That gives
4366 * the complete set of checks for data frames.
4367 */
4368 gen_or(b1, b0);
4369
4370 /*
4371 * Now check for a data frame.
4372 * I.e, check "link[0] & 0x08".
4373 */
4374 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4375 b1 = new_block(cstate, JMP(BPF_JSET));
4376 b1->s.k = 0x08;
4377 b1->stmts = s;
4378
4379 /*
4380 * AND that with the checks done for data frames.
4381 */
4382 gen_and(b1, b0);
4383
4384 /*
4385 * If the high-order bit of the type value is 0, this
4386 * is a management frame.
4387 * I.e, check "!(link[0] & 0x08)".
4388 */
4389 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4390 b2 = new_block(cstate, JMP(BPF_JSET));
4391 b2->s.k = 0x08;
4392 b2->stmts = s;
4393 gen_not(b2);
4394
4395 /*
4396 * For management frames, the DA is at 4.
4397 */
4398 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4399 gen_and(b2, b1);
4400
4401 /*
4402 * OR that with the checks done for data frames.
4403 * That gives the checks done for management and
4404 * data frames.
4405 */
4406 gen_or(b1, b0);
4407
4408 /*
4409 * If the low-order bit of the type value is 1,
4410 * this is either a control frame or a frame
4411 * with a reserved type, and thus not a
4412 * frame with an SA.
4413 *
4414 * I.e., check "!(link[0] & 0x04)".
4415 */
4416 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4417 b1 = new_block(cstate, JMP(BPF_JSET));
4418 b1->s.k = 0x04;
4419 b1->stmts = s;
4420 gen_not(b1);
4421
4422 /*
4423 * AND that with the checks for data and management
4424 * frames.
4425 */
4426 gen_and(b1, b0);
4427 return b0;
4428
4429 case Q_RA:
4430 /*
4431 * Not present in management frames; addr1 in other
4432 * frames.
4433 */
4434
4435 /*
4436 * If the high-order bit of the type value is 0, this
4437 * is a management frame.
4438 * I.e, check "(link[0] & 0x08)".
4439 */
4440 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4441 b1 = new_block(cstate, JMP(BPF_JSET));
4442 b1->s.k = 0x08;
4443 b1->stmts = s;
4444
4445 /*
4446 * Check addr1.
4447 */
4448 b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4449
4450 /*
4451 * AND that with the check of addr1.
4452 */
4453 gen_and(b1, b0);
4454 return (b0);
4455
4456 case Q_TA:
4457 /*
4458 * Not present in management frames; addr2, if present,
4459 * in other frames.
4460 */
4461
4462 /*
4463 * Not present in CTS or ACK control frames.
4464 */
4465 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4466 IEEE80211_FC0_TYPE_MASK);
4467 gen_not(b0);
4468 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4469 IEEE80211_FC0_SUBTYPE_MASK);
4470 gen_not(b1);
4471 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4472 IEEE80211_FC0_SUBTYPE_MASK);
4473 gen_not(b2);
4474 gen_and(b1, b2);
4475 gen_or(b0, b2);
4476
4477 /*
4478 * If the high-order bit of the type value is 0, this
4479 * is a management frame.
4480 * I.e, check "(link[0] & 0x08)".
4481 */
4482 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4483 b1 = new_block(cstate, JMP(BPF_JSET));
4484 b1->s.k = 0x08;
4485 b1->stmts = s;
4486
4487 /*
4488 * AND that with the check for frames other than
4489 * CTS and ACK frames.
4490 */
4491 gen_and(b1, b2);
4492
4493 /*
4494 * Check addr2.
4495 */
4496 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4497 gen_and(b2, b1);
4498 return b1;
4499
4500 /*
4501 * XXX - add BSSID keyword?
4502 */
4503 case Q_ADDR1:
4504 return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr));
4505
4506 case Q_ADDR2:
4507 /*
4508 * Not present in CTS or ACK control frames.
4509 */
4510 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4511 IEEE80211_FC0_TYPE_MASK);
4512 gen_not(b0);
4513 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4514 IEEE80211_FC0_SUBTYPE_MASK);
4515 gen_not(b1);
4516 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4517 IEEE80211_FC0_SUBTYPE_MASK);
4518 gen_not(b2);
4519 gen_and(b1, b2);
4520 gen_or(b0, b2);
4521 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4522 gen_and(b2, b1);
4523 return b1;
4524
4525 case Q_ADDR3:
4526 /*
4527 * Not present in control frames.
4528 */
4529 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4530 IEEE80211_FC0_TYPE_MASK);
4531 gen_not(b0);
4532 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4533 gen_and(b0, b1);
4534 return b1;
4535
4536 case Q_ADDR4:
4537 /*
4538 * Present only if the direction mask has both "From DS"
4539 * and "To DS" set. Neither control frames nor management
4540 * frames should have both of those set, so we don't
4541 * check the frame type.
4542 */
4543 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B,
4544 IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
4545 b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4546 gen_and(b0, b1);
4547 return b1;
4548
4549 case Q_AND:
4550 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4551 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4552 gen_and(b0, b1);
4553 return b1;
4554
4555 case Q_DEFAULT:
4556 case Q_OR:
4557 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4558 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4559 gen_or(b0, b1);
4560 return b1;
4561 }
4562 abort();
4563 /* NOTREACHED */
4564 }
4565
4566 /*
4567 * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
4568 * (We assume that the addresses are IEEE 48-bit MAC addresses,
4569 * as the RFC states.)
4570 */
4571 static struct block *
gen_ipfchostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4572 gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4573 {
4574 register struct block *b0, *b1;
4575
4576 switch (dir) {
4577 case Q_SRC:
4578 return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4579
4580 case Q_DST:
4581 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4582
4583 case Q_AND:
4584 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4585 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4586 gen_and(b0, b1);
4587 return b1;
4588
4589 case Q_DEFAULT:
4590 case Q_OR:
4591 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4592 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4593 gen_or(b0, b1);
4594 return b1;
4595
4596 case Q_ADDR1:
4597 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4598 break;
4599
4600 case Q_ADDR2:
4601 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4602 break;
4603
4604 case Q_ADDR3:
4605 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4606 break;
4607
4608 case Q_ADDR4:
4609 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4610 break;
4611
4612 case Q_RA:
4613 bpf_error(cstate, "'ra' is only supported on 802.11");
4614 break;
4615
4616 case Q_TA:
4617 bpf_error(cstate, "'ta' is only supported on 802.11");
4618 break;
4619 }
4620 abort();
4621 /* NOTREACHED */
4622 }
4623
4624 /*
4625 * This is quite tricky because there may be pad bytes in front of the
4626 * DECNET header, and then there are two possible data packet formats that
4627 * carry both src and dst addresses, plus 5 packet types in a format that
4628 * carries only the src node, plus 2 types that use a different format and
4629 * also carry just the src node.
4630 *
4631 * Yuck.
4632 *
4633 * Instead of doing those all right, we just look for data packets with
4634 * 0 or 1 bytes of padding. If you want to look at other packets, that
4635 * will require a lot more hacking.
4636 *
4637 * To add support for filtering on DECNET "areas" (network numbers)
4638 * one would want to add a "mask" argument to this routine. That would
4639 * make the filter even more inefficient, although one could be clever
4640 * and not generate masking instructions if the mask is 0xFFFF.
4641 */
4642 static struct block *
gen_dnhostop(compiler_state_t * cstate,bpf_u_int32 addr,int dir)4643 gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir)
4644 {
4645 struct block *b0, *b1, *b2, *tmp;
4646 u_int offset_lh; /* offset if long header is received */
4647 u_int offset_sh; /* offset if short header is received */
4648
4649 switch (dir) {
4650
4651 case Q_DST:
4652 offset_sh = 1; /* follows flags */
4653 offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
4654 break;
4655
4656 case Q_SRC:
4657 offset_sh = 3; /* follows flags, dstnode */
4658 offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
4659 break;
4660
4661 case Q_AND:
4662 /* Inefficient because we do our Calvinball dance twice */
4663 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4664 b1 = gen_dnhostop(cstate, addr, Q_DST);
4665 gen_and(b0, b1);
4666 return b1;
4667
4668 case Q_OR:
4669 case Q_DEFAULT:
4670 /* Inefficient because we do our Calvinball dance twice */
4671 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4672 b1 = gen_dnhostop(cstate, addr, Q_DST);
4673 gen_or(b0, b1);
4674 return b1;
4675
4676 case Q_ISO:
4677 bpf_error(cstate, "ISO host filtering not implemented");
4678
4679 default:
4680 abort();
4681 }
4682 b0 = gen_linktype(cstate, ETHERTYPE_DN);
4683 /* Check for pad = 1, long header case */
4684 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4685 (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
4686 b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh,
4687 BPF_H, (bpf_int32)ntohs((u_short)addr));
4688 gen_and(tmp, b1);
4689 /* Check for pad = 0, long header case */
4690 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
4691 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4692 gen_and(tmp, b2);
4693 gen_or(b2, b1);
4694 /* Check for pad = 1, short header case */
4695 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4696 (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
4697 b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4698 gen_and(tmp, b2);
4699 gen_or(b2, b1);
4700 /* Check for pad = 0, short header case */
4701 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
4702 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4703 gen_and(tmp, b2);
4704 gen_or(b2, b1);
4705
4706 /* Combine with test for cstate->linktype */
4707 gen_and(b0, b1);
4708 return b1;
4709 }
4710
4711 /*
4712 * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
4713 * test the bottom-of-stack bit, and then check the version number
4714 * field in the IP header.
4715 */
4716 static struct block *
gen_mpls_linktype(compiler_state_t * cstate,int proto)4717 gen_mpls_linktype(compiler_state_t *cstate, int proto)
4718 {
4719 struct block *b0, *b1;
4720
4721 switch (proto) {
4722
4723 case Q_IP:
4724 /* match the bottom-of-stack bit */
4725 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4726 /* match the IPv4 version number */
4727 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0);
4728 gen_and(b0, b1);
4729 return b1;
4730
4731 case Q_IPV6:
4732 /* match the bottom-of-stack bit */
4733 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4734 /* match the IPv4 version number */
4735 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
4736 gen_and(b0, b1);
4737 return b1;
4738
4739 default:
4740 abort();
4741 }
4742 }
4743
4744 static struct block *
gen_host(compiler_state_t * cstate,bpf_u_int32 addr,bpf_u_int32 mask,int proto,int dir,int type)4745 gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
4746 int proto, int dir, int type)
4747 {
4748 struct block *b0, *b1;
4749 const char *typestr;
4750
4751 if (type == Q_NET)
4752 typestr = "net";
4753 else
4754 typestr = "host";
4755
4756 switch (proto) {
4757
4758 case Q_DEFAULT:
4759 b0 = gen_host(cstate, addr, mask, Q_IP, dir, type);
4760 /*
4761 * Only check for non-IPv4 addresses if we're not
4762 * checking MPLS-encapsulated packets.
4763 */
4764 if (cstate->label_stack_depth == 0) {
4765 b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type);
4766 gen_or(b0, b1);
4767 b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type);
4768 gen_or(b1, b0);
4769 }
4770 return b0;
4771
4772 case Q_IP:
4773 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16);
4774
4775 case Q_RARP:
4776 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
4777
4778 case Q_ARP:
4779 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24);
4780
4781 case Q_TCP:
4782 bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4783
4784 case Q_SCTP:
4785 bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4786
4787 case Q_UDP:
4788 bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4789
4790 case Q_ICMP:
4791 bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4792
4793 case Q_IGMP:
4794 bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4795
4796 case Q_IGRP:
4797 bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4798
4799 case Q_PIM:
4800 bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4801
4802 case Q_VRRP:
4803 bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4804
4805 case Q_CARP:
4806 bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4807
4808 case Q_ATALK:
4809 bpf_error(cstate, "ATALK host filtering not implemented");
4810
4811 case Q_AARP:
4812 bpf_error(cstate, "AARP host filtering not implemented");
4813
4814 case Q_DECNET:
4815 return gen_dnhostop(cstate, addr, dir);
4816
4817 case Q_SCA:
4818 bpf_error(cstate, "SCA host filtering not implemented");
4819
4820 case Q_LAT:
4821 bpf_error(cstate, "LAT host filtering not implemented");
4822
4823 case Q_MOPDL:
4824 bpf_error(cstate, "MOPDL host filtering not implemented");
4825
4826 case Q_MOPRC:
4827 bpf_error(cstate, "MOPRC host filtering not implemented");
4828
4829 case Q_IPV6:
4830 bpf_error(cstate, "'ip6' modifier applied to ip host");
4831
4832 case Q_ICMPV6:
4833 bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4834
4835 case Q_AH:
4836 bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4837
4838 case Q_ESP:
4839 bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4840
4841 case Q_ISO:
4842 bpf_error(cstate, "ISO host filtering not implemented");
4843
4844 case Q_ESIS:
4845 bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4846
4847 case Q_ISIS:
4848 bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4849
4850 case Q_CLNP:
4851 bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4852
4853 case Q_STP:
4854 bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4855
4856 case Q_IPX:
4857 bpf_error(cstate, "IPX host filtering not implemented");
4858
4859 case Q_NETBEUI:
4860 bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4861
4862 case Q_RADIO:
4863 bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4864
4865 default:
4866 abort();
4867 }
4868 /* NOTREACHED */
4869 }
4870
4871 #ifdef INET6
4872 static struct block *
gen_host6(compiler_state_t * cstate,struct in6_addr * addr,struct in6_addr * mask,int proto,int dir,int type)4873 gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
4874 struct in6_addr *mask, int proto, int dir, int type)
4875 {
4876 const char *typestr;
4877
4878 if (type == Q_NET)
4879 typestr = "net";
4880 else
4881 typestr = "host";
4882
4883 switch (proto) {
4884
4885 case Q_DEFAULT:
4886 return gen_host6(cstate, addr, mask, Q_IPV6, dir, type);
4887
4888 case Q_LINK:
4889 bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr);
4890
4891 case Q_IP:
4892 bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr);
4893
4894 case Q_RARP:
4895 bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr);
4896
4897 case Q_ARP:
4898 bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr);
4899
4900 case Q_SCTP:
4901 bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4902
4903 case Q_TCP:
4904 bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4905
4906 case Q_UDP:
4907 bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4908
4909 case Q_ICMP:
4910 bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4911
4912 case Q_IGMP:
4913 bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4914
4915 case Q_IGRP:
4916 bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4917
4918 case Q_PIM:
4919 bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4920
4921 case Q_VRRP:
4922 bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
4923
4924 case Q_CARP:
4925 bpf_error(cstate, "'carp' modifier applied to %s", typestr);
4926
4927 case Q_ATALK:
4928 bpf_error(cstate, "ATALK host filtering not implemented");
4929
4930 case Q_AARP:
4931 bpf_error(cstate, "AARP host filtering not implemented");
4932
4933 case Q_DECNET:
4934 bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr);
4935
4936 case Q_SCA:
4937 bpf_error(cstate, "SCA host filtering not implemented");
4938
4939 case Q_LAT:
4940 bpf_error(cstate, "LAT host filtering not implemented");
4941
4942 case Q_MOPDL:
4943 bpf_error(cstate, "MOPDL host filtering not implemented");
4944
4945 case Q_MOPRC:
4946 bpf_error(cstate, "MOPRC host filtering not implemented");
4947
4948 case Q_IPV6:
4949 return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
4950
4951 case Q_ICMPV6:
4952 bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4953
4954 case Q_AH:
4955 bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4956
4957 case Q_ESP:
4958 bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4959
4960 case Q_ISO:
4961 bpf_error(cstate, "ISO host filtering not implemented");
4962
4963 case Q_ESIS:
4964 bpf_error(cstate, "'esis' modifier applied to %s", typestr);
4965
4966 case Q_ISIS:
4967 bpf_error(cstate, "'isis' modifier applied to %s", typestr);
4968
4969 case Q_CLNP:
4970 bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
4971
4972 case Q_STP:
4973 bpf_error(cstate, "'stp' modifier applied to %s", typestr);
4974
4975 case Q_IPX:
4976 bpf_error(cstate, "IPX host filtering not implemented");
4977
4978 case Q_NETBEUI:
4979 bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
4980
4981 case Q_RADIO:
4982 bpf_error(cstate, "'radio' modifier applied to %s", typestr);
4983
4984 default:
4985 abort();
4986 }
4987 /* NOTREACHED */
4988 }
4989 #endif
4990
4991 #ifndef INET6
4992 static struct block *
gen_gateway(compiler_state_t * cstate,const u_char * eaddr,struct addrinfo * alist,int proto,int dir)4993 gen_gateway(compiler_state_t *cstate, const u_char *eaddr,
4994 struct addrinfo *alist, int proto, int dir)
4995 {
4996 struct block *b0, *b1, *tmp;
4997 struct addrinfo *ai;
4998 struct sockaddr_in *sin;
4999
5000 if (dir != 0)
5001 bpf_error(cstate, "direction applied to 'gateway'");
5002
5003 switch (proto) {
5004 case Q_DEFAULT:
5005 case Q_IP:
5006 case Q_ARP:
5007 case Q_RARP:
5008 switch (cstate->linktype) {
5009 case DLT_EN10MB:
5010 case DLT_NETANALYZER:
5011 case DLT_NETANALYZER_TRANSPARENT:
5012 b1 = gen_prevlinkhdr_check(cstate);
5013 b0 = gen_ehostop(cstate, eaddr, Q_OR);
5014 if (b1 != NULL)
5015 gen_and(b1, b0);
5016 break;
5017 case DLT_FDDI:
5018 b0 = gen_fhostop(cstate, eaddr, Q_OR);
5019 break;
5020 case DLT_IEEE802:
5021 b0 = gen_thostop(cstate, eaddr, Q_OR);
5022 break;
5023 case DLT_IEEE802_11:
5024 case DLT_PRISM_HEADER:
5025 case DLT_IEEE802_11_RADIO_AVS:
5026 case DLT_IEEE802_11_RADIO:
5027 case DLT_PPI:
5028 b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
5029 break;
5030 case DLT_SUNATM:
5031 /*
5032 * This is LLC-multiplexed traffic; if it were
5033 * LANE, cstate->linktype would have been set to
5034 * DLT_EN10MB.
5035 */
5036 bpf_error(cstate,
5037 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5038 break;
5039 case DLT_IP_OVER_FC:
5040 b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
5041 break;
5042 default:
5043 bpf_error(cstate,
5044 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5045 }
5046 b1 = NULL;
5047 for (ai = alist; ai != NULL; ai = ai->ai_next) {
5048 /*
5049 * Does it have an address?
5050 */
5051 if (ai->ai_addr != NULL) {
5052 /*
5053 * Yes. Is it an IPv4 address?
5054 */
5055 if (ai->ai_addr->sa_family == AF_INET) {
5056 /*
5057 * Generate an entry for it.
5058 */
5059 sin = (struct sockaddr_in *)ai->ai_addr;
5060 tmp = gen_host(cstate,
5061 ntohl(sin->sin_addr.s_addr),
5062 0xffffffff, proto, Q_OR, Q_HOST);
5063 /*
5064 * Is it the *first* IPv4 address?
5065 */
5066 if (b1 == NULL) {
5067 /*
5068 * Yes, so start with it.
5069 */
5070 b1 = tmp;
5071 } else {
5072 /*
5073 * No, so OR it into the
5074 * existing set of
5075 * addresses.
5076 */
5077 gen_or(b1, tmp);
5078 b1 = tmp;
5079 }
5080 }
5081 }
5082 }
5083 if (b1 == NULL) {
5084 /*
5085 * No IPv4 addresses found.
5086 */
5087 return (NULL);
5088 }
5089 gen_not(b1);
5090 gen_and(b0, b1);
5091 return b1;
5092 }
5093 bpf_error(cstate, "illegal modifier of 'gateway'");
5094 /* NOTREACHED */
5095 }
5096 #endif
5097
5098 struct block *
gen_proto_abbrev(compiler_state_t * cstate,int proto)5099 gen_proto_abbrev(compiler_state_t *cstate, int proto)
5100 {
5101 struct block *b0;
5102 struct block *b1;
5103
5104 switch (proto) {
5105
5106 case Q_SCTP:
5107 b1 = gen_proto(cstate, IPPROTO_SCTP, Q_IP, Q_DEFAULT);
5108 b0 = gen_proto(cstate, IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
5109 gen_or(b0, b1);
5110 break;
5111
5112 case Q_TCP:
5113 b1 = gen_proto(cstate, IPPROTO_TCP, Q_IP, Q_DEFAULT);
5114 b0 = gen_proto(cstate, IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
5115 gen_or(b0, b1);
5116 break;
5117
5118 case Q_UDP:
5119 b1 = gen_proto(cstate, IPPROTO_UDP, Q_IP, Q_DEFAULT);
5120 b0 = gen_proto(cstate, IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
5121 gen_or(b0, b1);
5122 break;
5123
5124 case Q_ICMP:
5125 b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT);
5126 break;
5127
5128 #ifndef IPPROTO_IGMP
5129 #define IPPROTO_IGMP 2
5130 #endif
5131
5132 case Q_IGMP:
5133 b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT);
5134 break;
5135
5136 #ifndef IPPROTO_IGRP
5137 #define IPPROTO_IGRP 9
5138 #endif
5139 case Q_IGRP:
5140 b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT);
5141 break;
5142
5143 #ifndef IPPROTO_PIM
5144 #define IPPROTO_PIM 103
5145 #endif
5146
5147 case Q_PIM:
5148 b1 = gen_proto(cstate, IPPROTO_PIM, Q_IP, Q_DEFAULT);
5149 b0 = gen_proto(cstate, IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
5150 gen_or(b0, b1);
5151 break;
5152
5153 #ifndef IPPROTO_VRRP
5154 #define IPPROTO_VRRP 112
5155 #endif
5156
5157 case Q_VRRP:
5158 b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT);
5159 break;
5160
5161 #ifndef IPPROTO_CARP
5162 #define IPPROTO_CARP 112
5163 #endif
5164
5165 case Q_CARP:
5166 b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT);
5167 break;
5168
5169 case Q_IP:
5170 b1 = gen_linktype(cstate, ETHERTYPE_IP);
5171 break;
5172
5173 case Q_ARP:
5174 b1 = gen_linktype(cstate, ETHERTYPE_ARP);
5175 break;
5176
5177 case Q_RARP:
5178 b1 = gen_linktype(cstate, ETHERTYPE_REVARP);
5179 break;
5180
5181 case Q_LINK:
5182 bpf_error(cstate, "link layer applied in wrong context");
5183
5184 case Q_ATALK:
5185 b1 = gen_linktype(cstate, ETHERTYPE_ATALK);
5186 break;
5187
5188 case Q_AARP:
5189 b1 = gen_linktype(cstate, ETHERTYPE_AARP);
5190 break;
5191
5192 case Q_DECNET:
5193 b1 = gen_linktype(cstate, ETHERTYPE_DN);
5194 break;
5195
5196 case Q_SCA:
5197 b1 = gen_linktype(cstate, ETHERTYPE_SCA);
5198 break;
5199
5200 case Q_LAT:
5201 b1 = gen_linktype(cstate, ETHERTYPE_LAT);
5202 break;
5203
5204 case Q_MOPDL:
5205 b1 = gen_linktype(cstate, ETHERTYPE_MOPDL);
5206 break;
5207
5208 case Q_MOPRC:
5209 b1 = gen_linktype(cstate, ETHERTYPE_MOPRC);
5210 break;
5211
5212 case Q_IPV6:
5213 b1 = gen_linktype(cstate, ETHERTYPE_IPV6);
5214 break;
5215
5216 #ifndef IPPROTO_ICMPV6
5217 #define IPPROTO_ICMPV6 58
5218 #endif
5219 case Q_ICMPV6:
5220 b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
5221 break;
5222
5223 #ifndef IPPROTO_AH
5224 #define IPPROTO_AH 51
5225 #endif
5226 case Q_AH:
5227 b1 = gen_proto(cstate, IPPROTO_AH, Q_IP, Q_DEFAULT);
5228 b0 = gen_proto(cstate, IPPROTO_AH, Q_IPV6, Q_DEFAULT);
5229 gen_or(b0, b1);
5230 break;
5231
5232 #ifndef IPPROTO_ESP
5233 #define IPPROTO_ESP 50
5234 #endif
5235 case Q_ESP:
5236 b1 = gen_proto(cstate, IPPROTO_ESP, Q_IP, Q_DEFAULT);
5237 b0 = gen_proto(cstate, IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
5238 gen_or(b0, b1);
5239 break;
5240
5241 case Q_ISO:
5242 b1 = gen_linktype(cstate, LLCSAP_ISONS);
5243 break;
5244
5245 case Q_ESIS:
5246 b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT);
5247 break;
5248
5249 case Q_ISIS:
5250 b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
5251 break;
5252
5253 case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
5254 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5255 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5256 gen_or(b0, b1);
5257 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5258 gen_or(b0, b1);
5259 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5260 gen_or(b0, b1);
5261 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5262 gen_or(b0, b1);
5263 break;
5264
5265 case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
5266 b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5267 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5268 gen_or(b0, b1);
5269 b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5270 gen_or(b0, b1);
5271 b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5272 gen_or(b0, b1);
5273 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5274 gen_or(b0, b1);
5275 break;
5276
5277 case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
5278 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5279 b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5280 gen_or(b0, b1);
5281 b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
5282 gen_or(b0, b1);
5283 break;
5284
5285 case Q_ISIS_LSP:
5286 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5287 b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5288 gen_or(b0, b1);
5289 break;
5290
5291 case Q_ISIS_SNP:
5292 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5293 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5294 gen_or(b0, b1);
5295 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5296 gen_or(b0, b1);
5297 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5298 gen_or(b0, b1);
5299 break;
5300
5301 case Q_ISIS_CSNP:
5302 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5303 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5304 gen_or(b0, b1);
5305 break;
5306
5307 case Q_ISIS_PSNP:
5308 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5309 b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5310 gen_or(b0, b1);
5311 break;
5312
5313 case Q_CLNP:
5314 b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT);
5315 break;
5316
5317 case Q_STP:
5318 b1 = gen_linktype(cstate, LLCSAP_8021D);
5319 break;
5320
5321 case Q_IPX:
5322 b1 = gen_linktype(cstate, LLCSAP_IPX);
5323 break;
5324
5325 case Q_NETBEUI:
5326 b1 = gen_linktype(cstate, LLCSAP_NETBEUI);
5327 break;
5328
5329 case Q_RADIO:
5330 bpf_error(cstate, "'radio' is not a valid protocol type");
5331
5332 default:
5333 abort();
5334 }
5335 return b1;
5336 }
5337
5338 static struct block *
gen_ipfrag(compiler_state_t * cstate)5339 gen_ipfrag(compiler_state_t *cstate)
5340 {
5341 struct slist *s;
5342 struct block *b;
5343
5344 /* not IPv4 frag other than the first frag */
5345 s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H);
5346 b = new_block(cstate, JMP(BPF_JSET));
5347 b->s.k = 0x1fff;
5348 b->stmts = s;
5349 gen_not(b);
5350
5351 return b;
5352 }
5353
5354 /*
5355 * Generate a comparison to a port value in the transport-layer header
5356 * at the specified offset from the beginning of that header.
5357 *
5358 * XXX - this handles a variable-length prefix preceding the link-layer
5359 * header, such as the radiotap or AVS radio prefix, but doesn't handle
5360 * variable-length link-layer headers (such as Token Ring or 802.11
5361 * headers).
5362 */
5363 static struct block *
gen_portatom(compiler_state_t * cstate,int off,bpf_int32 v)5364 gen_portatom(compiler_state_t *cstate, int off, bpf_int32 v)
5365 {
5366 return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
5367 }
5368
5369 static struct block *
gen_portatom6(compiler_state_t * cstate,int off,bpf_int32 v)5370 gen_portatom6(compiler_state_t *cstate, int off, bpf_int32 v)
5371 {
5372 return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
5373 }
5374
5375 struct block *
gen_portop(compiler_state_t * cstate,int port,int proto,int dir)5376 gen_portop(compiler_state_t *cstate, int port, int proto, int dir)
5377 {
5378 struct block *b0, *b1, *tmp;
5379
5380 /* ip proto 'proto' and not a fragment other than the first fragment */
5381 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5382 b0 = gen_ipfrag(cstate);
5383 gen_and(tmp, b0);
5384
5385 switch (dir) {
5386 case Q_SRC:
5387 b1 = gen_portatom(cstate, 0, (bpf_int32)port);
5388 break;
5389
5390 case Q_DST:
5391 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5392 break;
5393
5394 case Q_OR:
5395 case Q_DEFAULT:
5396 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5397 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5398 gen_or(tmp, b1);
5399 break;
5400
5401 case Q_AND:
5402 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5403 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5404 gen_and(tmp, b1);
5405 break;
5406
5407 default:
5408 abort();
5409 }
5410 gen_and(b0, b1);
5411
5412 return b1;
5413 }
5414
5415 static struct block *
gen_port(compiler_state_t * cstate,int port,int ip_proto,int dir)5416 gen_port(compiler_state_t *cstate, int port, int ip_proto, int dir)
5417 {
5418 struct block *b0, *b1, *tmp;
5419
5420 /*
5421 * ether proto ip
5422 *
5423 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
5424 * not LLC encapsulation with LLCSAP_IP.
5425 *
5426 * For IEEE 802 networks - which includes 802.5 token ring
5427 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
5428 * says that SNAP encapsulation is used, not LLC encapsulation
5429 * with LLCSAP_IP.
5430 *
5431 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
5432 * RFC 2225 say that SNAP encapsulation is used, not LLC
5433 * encapsulation with LLCSAP_IP.
5434 *
5435 * So we always check for ETHERTYPE_IP.
5436 */
5437 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5438
5439 switch (ip_proto) {
5440 case IPPROTO_UDP:
5441 case IPPROTO_TCP:
5442 case IPPROTO_SCTP:
5443 b1 = gen_portop(cstate, port, ip_proto, dir);
5444 break;
5445
5446 case PROTO_UNDEF:
5447 tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
5448 b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
5449 gen_or(tmp, b1);
5450 tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
5451 gen_or(tmp, b1);
5452 break;
5453
5454 default:
5455 abort();
5456 }
5457 gen_and(b0, b1);
5458 return b1;
5459 }
5460
5461 struct block *
gen_portop6(compiler_state_t * cstate,int port,int proto,int dir)5462 gen_portop6(compiler_state_t *cstate, int port, int proto, int dir)
5463 {
5464 struct block *b0, *b1, *tmp;
5465
5466 /* ip6 proto 'proto' */
5467 /* XXX - catch the first fragment of a fragmented packet? */
5468 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5469
5470 switch (dir) {
5471 case Q_SRC:
5472 b1 = gen_portatom6(cstate, 0, (bpf_int32)port);
5473 break;
5474
5475 case Q_DST:
5476 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5477 break;
5478
5479 case Q_OR:
5480 case Q_DEFAULT:
5481 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5482 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5483 gen_or(tmp, b1);
5484 break;
5485
5486 case Q_AND:
5487 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5488 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5489 gen_and(tmp, b1);
5490 break;
5491
5492 default:
5493 abort();
5494 }
5495 gen_and(b0, b1);
5496
5497 return b1;
5498 }
5499
5500 static struct block *
gen_port6(compiler_state_t * cstate,int port,int ip_proto,int dir)5501 gen_port6(compiler_state_t *cstate, int port, int ip_proto, int dir)
5502 {
5503 struct block *b0, *b1, *tmp;
5504
5505 /* link proto ip6 */
5506 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5507
5508 switch (ip_proto) {
5509 case IPPROTO_UDP:
5510 case IPPROTO_TCP:
5511 case IPPROTO_SCTP:
5512 b1 = gen_portop6(cstate, port, ip_proto, dir);
5513 break;
5514
5515 case PROTO_UNDEF:
5516 tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
5517 b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
5518 gen_or(tmp, b1);
5519 tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
5520 gen_or(tmp, b1);
5521 break;
5522
5523 default:
5524 abort();
5525 }
5526 gen_and(b0, b1);
5527 return b1;
5528 }
5529
5530 /* gen_portrange code */
5531 static struct block *
gen_portrangeatom(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5532 gen_portrangeatom(compiler_state_t *cstate, int off, bpf_int32 v1,
5533 bpf_int32 v2)
5534 {
5535 struct block *b1, *b2;
5536
5537 if (v1 > v2) {
5538 /*
5539 * Reverse the order of the ports, so v1 is the lower one.
5540 */
5541 bpf_int32 vtemp;
5542
5543 vtemp = v1;
5544 v1 = v2;
5545 v2 = vtemp;
5546 }
5547
5548 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1);
5549 b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2);
5550
5551 gen_and(b1, b2);
5552
5553 return b2;
5554 }
5555
5556 struct block *
gen_portrangeop(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5557 gen_portrangeop(compiler_state_t *cstate, int port1, int port2, int proto,
5558 int dir)
5559 {
5560 struct block *b0, *b1, *tmp;
5561
5562 /* ip proto 'proto' and not a fragment other than the first fragment */
5563 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5564 b0 = gen_ipfrag(cstate);
5565 gen_and(tmp, b0);
5566
5567 switch (dir) {
5568 case Q_SRC:
5569 b1 = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5570 break;
5571
5572 case Q_DST:
5573 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5574 break;
5575
5576 case Q_OR:
5577 case Q_DEFAULT:
5578 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5579 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5580 gen_or(tmp, b1);
5581 break;
5582
5583 case Q_AND:
5584 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5585 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5586 gen_and(tmp, b1);
5587 break;
5588
5589 default:
5590 abort();
5591 }
5592 gen_and(b0, b1);
5593
5594 return b1;
5595 }
5596
5597 static struct block *
gen_portrange(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5598 gen_portrange(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5599 int dir)
5600 {
5601 struct block *b0, *b1, *tmp;
5602
5603 /* link proto ip */
5604 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5605
5606 switch (ip_proto) {
5607 case IPPROTO_UDP:
5608 case IPPROTO_TCP:
5609 case IPPROTO_SCTP:
5610 b1 = gen_portrangeop(cstate, port1, port2, ip_proto, dir);
5611 break;
5612
5613 case PROTO_UNDEF:
5614 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
5615 b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
5616 gen_or(tmp, b1);
5617 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
5618 gen_or(tmp, b1);
5619 break;
5620
5621 default:
5622 abort();
5623 }
5624 gen_and(b0, b1);
5625 return b1;
5626 }
5627
5628 static struct block *
gen_portrangeatom6(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5629 gen_portrangeatom6(compiler_state_t *cstate, int off, bpf_int32 v1,
5630 bpf_int32 v2)
5631 {
5632 struct block *b1, *b2;
5633
5634 if (v1 > v2) {
5635 /*
5636 * Reverse the order of the ports, so v1 is the lower one.
5637 */
5638 bpf_int32 vtemp;
5639
5640 vtemp = v1;
5641 v1 = v2;
5642 v2 = vtemp;
5643 }
5644
5645 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1);
5646 b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2);
5647
5648 gen_and(b1, b2);
5649
5650 return b2;
5651 }
5652
5653 struct block *
gen_portrangeop6(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5654 gen_portrangeop6(compiler_state_t *cstate, int port1, int port2, int proto,
5655 int dir)
5656 {
5657 struct block *b0, *b1, *tmp;
5658
5659 /* ip6 proto 'proto' */
5660 /* XXX - catch the first fragment of a fragmented packet? */
5661 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5662
5663 switch (dir) {
5664 case Q_SRC:
5665 b1 = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5666 break;
5667
5668 case Q_DST:
5669 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5670 break;
5671
5672 case Q_OR:
5673 case Q_DEFAULT:
5674 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5675 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5676 gen_or(tmp, b1);
5677 break;
5678
5679 case Q_AND:
5680 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5681 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5682 gen_and(tmp, b1);
5683 break;
5684
5685 default:
5686 abort();
5687 }
5688 gen_and(b0, b1);
5689
5690 return b1;
5691 }
5692
5693 static struct block *
gen_portrange6(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5694 gen_portrange6(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5695 int dir)
5696 {
5697 struct block *b0, *b1, *tmp;
5698
5699 /* link proto ip6 */
5700 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5701
5702 switch (ip_proto) {
5703 case IPPROTO_UDP:
5704 case IPPROTO_TCP:
5705 case IPPROTO_SCTP:
5706 b1 = gen_portrangeop6(cstate, port1, port2, ip_proto, dir);
5707 break;
5708
5709 case PROTO_UNDEF:
5710 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
5711 b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
5712 gen_or(tmp, b1);
5713 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
5714 gen_or(tmp, b1);
5715 break;
5716
5717 default:
5718 abort();
5719 }
5720 gen_and(b0, b1);
5721 return b1;
5722 }
5723
5724 static int
lookup_proto(compiler_state_t * cstate,const char * name,int proto)5725 lookup_proto(compiler_state_t *cstate, const char *name, int proto)
5726 {
5727 register int v;
5728
5729 switch (proto) {
5730
5731 case Q_DEFAULT:
5732 case Q_IP:
5733 case Q_IPV6:
5734 v = pcap_nametoproto(name);
5735 if (v == PROTO_UNDEF)
5736 bpf_error(cstate, "unknown ip proto '%s'", name);
5737 break;
5738
5739 case Q_LINK:
5740 /* XXX should look up h/w protocol type based on cstate->linktype */
5741 v = pcap_nametoeproto(name);
5742 if (v == PROTO_UNDEF) {
5743 v = pcap_nametollc(name);
5744 if (v == PROTO_UNDEF)
5745 bpf_error(cstate, "unknown ether proto '%s'", name);
5746 }
5747 break;
5748
5749 case Q_ISO:
5750 if (strcmp(name, "esis") == 0)
5751 v = ISO9542_ESIS;
5752 else if (strcmp(name, "isis") == 0)
5753 v = ISO10589_ISIS;
5754 else if (strcmp(name, "clnp") == 0)
5755 v = ISO8473_CLNP;
5756 else
5757 bpf_error(cstate, "unknown osi proto '%s'", name);
5758 break;
5759
5760 default:
5761 v = PROTO_UNDEF;
5762 break;
5763 }
5764 return v;
5765 }
5766
5767 #if 0
5768 struct stmt *
5769 gen_joinsp(struct stmt **s, int n)
5770 {
5771 return NULL;
5772 }
5773 #endif
5774
5775 static struct block *
gen_protochain(compiler_state_t * cstate,int v,int proto,int dir)5776 gen_protochain(compiler_state_t *cstate, int v, int proto, int dir)
5777 {
5778 #ifdef NO_PROTOCHAIN
5779 return gen_proto(cstate, v, proto, dir);
5780 #else
5781 struct block *b0, *b;
5782 struct slist *s[100];
5783 int fix2, fix3, fix4, fix5;
5784 int ahcheck, again, end;
5785 int i, max;
5786 int reg2 = alloc_reg(cstate);
5787
5788 memset(s, 0, sizeof(s));
5789 fix3 = fix4 = fix5 = 0;
5790
5791 switch (proto) {
5792 case Q_IP:
5793 case Q_IPV6:
5794 break;
5795 case Q_DEFAULT:
5796 b0 = gen_protochain(cstate, v, Q_IP, dir);
5797 b = gen_protochain(cstate, v, Q_IPV6, dir);
5798 gen_or(b0, b);
5799 return b;
5800 default:
5801 bpf_error(cstate, "bad protocol applied for 'protochain'");
5802 /*NOTREACHED*/
5803 }
5804
5805 /*
5806 * We don't handle variable-length prefixes before the link-layer
5807 * header, or variable-length link-layer headers, here yet.
5808 * We might want to add BPF instructions to do the protochain
5809 * work, to simplify that and, on platforms that have a BPF
5810 * interpreter with the new instructions, let the filtering
5811 * be done in the kernel. (We already require a modified BPF
5812 * engine to do the protochain stuff, to support backward
5813 * branches, and backward branch support is unlikely to appear
5814 * in kernel BPF engines.)
5815 */
5816 if (cstate->off_linkpl.is_variable)
5817 bpf_error(cstate, "'protochain' not supported with variable length headers");
5818
5819 cstate->no_optimize = 1; /* this code is not compatible with optimizer yet */
5820
5821 /*
5822 * s[0] is a dummy entry to protect other BPF insn from damage
5823 * by s[fix] = foo with uninitialized variable "fix". It is somewhat
5824 * hard to find interdependency made by jump table fixup.
5825 */
5826 i = 0;
5827 s[i] = new_stmt(cstate, 0); /*dummy*/
5828 i++;
5829
5830 switch (proto) {
5831 case Q_IP:
5832 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5833
5834 /* A = ip->ip_p */
5835 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5836 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9;
5837 i++;
5838 /* X = ip->ip_hl << 2 */
5839 s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
5840 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5841 i++;
5842 break;
5843
5844 case Q_IPV6:
5845 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5846
5847 /* A = ip6->ip_nxt */
5848 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
5849 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6;
5850 i++;
5851 /* X = sizeof(struct ip6_hdr) */
5852 s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM);
5853 s[i]->s.k = 40;
5854 i++;
5855 break;
5856
5857 default:
5858 bpf_error(cstate, "unsupported proto to gen_protochain");
5859 /*NOTREACHED*/
5860 }
5861
5862 /* again: if (A == v) goto end; else fall through; */
5863 again = i;
5864 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5865 s[i]->s.k = v;
5866 s[i]->s.jt = NULL; /*later*/
5867 s[i]->s.jf = NULL; /*update in next stmt*/
5868 fix5 = i;
5869 i++;
5870
5871 #ifndef IPPROTO_NONE
5872 #define IPPROTO_NONE 59
5873 #endif
5874 /* if (A == IPPROTO_NONE) goto end */
5875 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5876 s[i]->s.jt = NULL; /*later*/
5877 s[i]->s.jf = NULL; /*update in next stmt*/
5878 s[i]->s.k = IPPROTO_NONE;
5879 s[fix5]->s.jf = s[i];
5880 fix2 = i;
5881 i++;
5882
5883 if (proto == Q_IPV6) {
5884 int v6start, v6end, v6advance, j;
5885
5886 v6start = i;
5887 /* if (A == IPPROTO_HOPOPTS) goto v6advance */
5888 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5889 s[i]->s.jt = NULL; /*later*/
5890 s[i]->s.jf = NULL; /*update in next stmt*/
5891 s[i]->s.k = IPPROTO_HOPOPTS;
5892 s[fix2]->s.jf = s[i];
5893 i++;
5894 /* if (A == IPPROTO_DSTOPTS) goto v6advance */
5895 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5896 s[i]->s.jt = NULL; /*later*/
5897 s[i]->s.jf = NULL; /*update in next stmt*/
5898 s[i]->s.k = IPPROTO_DSTOPTS;
5899 i++;
5900 /* if (A == IPPROTO_ROUTING) goto v6advance */
5901 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5902 s[i]->s.jt = NULL; /*later*/
5903 s[i]->s.jf = NULL; /*update in next stmt*/
5904 s[i]->s.k = IPPROTO_ROUTING;
5905 i++;
5906 /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
5907 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5908 s[i]->s.jt = NULL; /*later*/
5909 s[i]->s.jf = NULL; /*later*/
5910 s[i]->s.k = IPPROTO_FRAGMENT;
5911 fix3 = i;
5912 v6end = i;
5913 i++;
5914
5915 /* v6advance: */
5916 v6advance = i;
5917
5918 /*
5919 * in short,
5920 * A = P[X + packet head];
5921 * X = X + (P[X + packet head + 1] + 1) * 8;
5922 */
5923 /* A = P[X + packet head] */
5924 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5925 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5926 i++;
5927 /* MEM[reg2] = A */
5928 s[i] = new_stmt(cstate, BPF_ST);
5929 s[i]->s.k = reg2;
5930 i++;
5931 /* A = P[X + packet head + 1]; */
5932 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5933 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1;
5934 i++;
5935 /* A += 1 */
5936 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5937 s[i]->s.k = 1;
5938 i++;
5939 /* A *= 8 */
5940 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
5941 s[i]->s.k = 8;
5942 i++;
5943 /* A += X */
5944 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
5945 s[i]->s.k = 0;
5946 i++;
5947 /* X = A; */
5948 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
5949 i++;
5950 /* A = MEM[reg2] */
5951 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
5952 s[i]->s.k = reg2;
5953 i++;
5954
5955 /* goto again; (must use BPF_JA for backward jump) */
5956 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
5957 s[i]->s.k = again - i - 1;
5958 s[i - 1]->s.jf = s[i];
5959 i++;
5960
5961 /* fixup */
5962 for (j = v6start; j <= v6end; j++)
5963 s[j]->s.jt = s[v6advance];
5964 } else {
5965 /* nop */
5966 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
5967 s[i]->s.k = 0;
5968 s[fix2]->s.jf = s[i];
5969 i++;
5970 }
5971
5972 /* ahcheck: */
5973 ahcheck = i;
5974 /* if (A == IPPROTO_AH) then fall through; else goto end; */
5975 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
5976 s[i]->s.jt = NULL; /*later*/
5977 s[i]->s.jf = NULL; /*later*/
5978 s[i]->s.k = IPPROTO_AH;
5979 if (fix3)
5980 s[fix3]->s.jf = s[ahcheck];
5981 fix4 = i;
5982 i++;
5983
5984 /*
5985 * in short,
5986 * A = P[X];
5987 * X = X + (P[X + 1] + 2) * 4;
5988 */
5989 /* A = X */
5990 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
5991 i++;
5992 /* A = P[X + packet head]; */
5993 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
5994 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
5995 i++;
5996 /* MEM[reg2] = A */
5997 s[i] = new_stmt(cstate, BPF_ST);
5998 s[i]->s.k = reg2;
5999 i++;
6000 /* A = X */
6001 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
6002 i++;
6003 /* A += 1 */
6004 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6005 s[i]->s.k = 1;
6006 i++;
6007 /* X = A */
6008 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6009 i++;
6010 /* A = P[X + packet head] */
6011 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6012 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6013 i++;
6014 /* A += 2 */
6015 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6016 s[i]->s.k = 2;
6017 i++;
6018 /* A *= 4 */
6019 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
6020 s[i]->s.k = 4;
6021 i++;
6022 /* X = A; */
6023 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6024 i++;
6025 /* A = MEM[reg2] */
6026 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
6027 s[i]->s.k = reg2;
6028 i++;
6029
6030 /* goto again; (must use BPF_JA for backward jump) */
6031 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
6032 s[i]->s.k = again - i - 1;
6033 i++;
6034
6035 /* end: nop */
6036 end = i;
6037 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6038 s[i]->s.k = 0;
6039 s[fix2]->s.jt = s[end];
6040 s[fix4]->s.jf = s[end];
6041 s[fix5]->s.jt = s[end];
6042 i++;
6043
6044 /*
6045 * make slist chain
6046 */
6047 max = i;
6048 for (i = 0; i < max - 1; i++)
6049 s[i]->next = s[i + 1];
6050 s[max - 1]->next = NULL;
6051
6052 /*
6053 * emit final check
6054 */
6055 b = new_block(cstate, JMP(BPF_JEQ));
6056 b->stmts = s[1]; /*remember, s[0] is dummy*/
6057 b->s.k = v;
6058
6059 free_reg(cstate, reg2);
6060
6061 gen_and(b0, b);
6062 return b;
6063 #endif
6064 }
6065
6066 static struct block *
gen_check_802_11_data_frame(compiler_state_t * cstate)6067 gen_check_802_11_data_frame(compiler_state_t *cstate)
6068 {
6069 struct slist *s;
6070 struct block *b0, *b1;
6071
6072 /*
6073 * A data frame has the 0x08 bit (b3) in the frame control field set
6074 * and the 0x04 bit (b2) clear.
6075 */
6076 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6077 b0 = new_block(cstate, JMP(BPF_JSET));
6078 b0->s.k = 0x08;
6079 b0->stmts = s;
6080
6081 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6082 b1 = new_block(cstate, JMP(BPF_JSET));
6083 b1->s.k = 0x04;
6084 b1->stmts = s;
6085 gen_not(b1);
6086
6087 gen_and(b1, b0);
6088
6089 return b0;
6090 }
6091
6092 /*
6093 * Generate code that checks whether the packet is a packet for protocol
6094 * <proto> and whether the type field in that protocol's header has
6095 * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
6096 * IP packet and checks the protocol number in the IP header against <v>.
6097 *
6098 * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
6099 * against Q_IP and Q_IPV6.
6100 */
6101 static struct block *
gen_proto(compiler_state_t * cstate,int v,int proto,int dir)6102 gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
6103 {
6104 struct block *b0, *b1;
6105 #ifndef CHASE_CHAIN
6106 struct block *b2;
6107 #endif
6108
6109 if (dir != Q_DEFAULT)
6110 bpf_error(cstate, "direction applied to 'proto'");
6111
6112 switch (proto) {
6113 case Q_DEFAULT:
6114 b0 = gen_proto(cstate, v, Q_IP, dir);
6115 b1 = gen_proto(cstate, v, Q_IPV6, dir);
6116 gen_or(b0, b1);
6117 return b1;
6118
6119 case Q_IP:
6120 /*
6121 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
6122 * not LLC encapsulation with LLCSAP_IP.
6123 *
6124 * For IEEE 802 networks - which includes 802.5 token ring
6125 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
6126 * says that SNAP encapsulation is used, not LLC encapsulation
6127 * with LLCSAP_IP.
6128 *
6129 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
6130 * RFC 2225 say that SNAP encapsulation is used, not LLC
6131 * encapsulation with LLCSAP_IP.
6132 *
6133 * So we always check for ETHERTYPE_IP.
6134 */
6135 b0 = gen_linktype(cstate, ETHERTYPE_IP);
6136 #ifndef CHASE_CHAIN
6137 b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)v);
6138 #else
6139 b1 = gen_protochain(cstate, v, Q_IP);
6140 #endif
6141 gen_and(b0, b1);
6142 return b1;
6143
6144 case Q_ISO:
6145 switch (cstate->linktype) {
6146
6147 case DLT_FRELAY:
6148 /*
6149 * Frame Relay packets typically have an OSI
6150 * NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)"
6151 * generates code to check for all the OSI
6152 * NLPIDs, so calling it and then adding a check
6153 * for the particular NLPID for which we're
6154 * looking is bogus, as we can just check for
6155 * the NLPID.
6156 *
6157 * What we check for is the NLPID and a frame
6158 * control field value of UI, i.e. 0x03 followed
6159 * by the NLPID.
6160 *
6161 * XXX - assumes a 2-byte Frame Relay header with
6162 * DLCI and flags. What if the address is longer?
6163 *
6164 * XXX - what about SNAP-encapsulated frames?
6165 */
6166 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v);
6167 /*NOTREACHED*/
6168 break;
6169
6170 case DLT_C_HDLC:
6171 /*
6172 * Cisco uses an Ethertype lookalike - for OSI,
6173 * it's 0xfefe.
6174 */
6175 b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
6176 /* OSI in C-HDLC is stuffed with a fudge byte */
6177 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
6178 gen_and(b0, b1);
6179 return b1;
6180
6181 default:
6182 b0 = gen_linktype(cstate, LLCSAP_ISONS);
6183 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
6184 gen_and(b0, b1);
6185 return b1;
6186 }
6187
6188 case Q_ISIS:
6189 b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
6190 /*
6191 * 4 is the offset of the PDU type relative to the IS-IS
6192 * header.
6193 */
6194 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
6195 gen_and(b0, b1);
6196 return b1;
6197
6198 case Q_ARP:
6199 bpf_error(cstate, "arp does not encapsulate another protocol");
6200 /* NOTREACHED */
6201
6202 case Q_RARP:
6203 bpf_error(cstate, "rarp does not encapsulate another protocol");
6204 /* NOTREACHED */
6205
6206 case Q_ATALK:
6207 bpf_error(cstate, "atalk encapsulation is not specifiable");
6208 /* NOTREACHED */
6209
6210 case Q_DECNET:
6211 bpf_error(cstate, "decnet encapsulation is not specifiable");
6212 /* NOTREACHED */
6213
6214 case Q_SCA:
6215 bpf_error(cstate, "sca does not encapsulate another protocol");
6216 /* NOTREACHED */
6217
6218 case Q_LAT:
6219 bpf_error(cstate, "lat does not encapsulate another protocol");
6220 /* NOTREACHED */
6221
6222 case Q_MOPRC:
6223 bpf_error(cstate, "moprc does not encapsulate another protocol");
6224 /* NOTREACHED */
6225
6226 case Q_MOPDL:
6227 bpf_error(cstate, "mopdl does not encapsulate another protocol");
6228 /* NOTREACHED */
6229
6230 case Q_LINK:
6231 return gen_linktype(cstate, v);
6232
6233 case Q_UDP:
6234 bpf_error(cstate, "'udp proto' is bogus");
6235 /* NOTREACHED */
6236
6237 case Q_TCP:
6238 bpf_error(cstate, "'tcp proto' is bogus");
6239 /* NOTREACHED */
6240
6241 case Q_SCTP:
6242 bpf_error(cstate, "'sctp proto' is bogus");
6243 /* NOTREACHED */
6244
6245 case Q_ICMP:
6246 bpf_error(cstate, "'icmp proto' is bogus");
6247 /* NOTREACHED */
6248
6249 case Q_IGMP:
6250 bpf_error(cstate, "'igmp proto' is bogus");
6251 /* NOTREACHED */
6252
6253 case Q_IGRP:
6254 bpf_error(cstate, "'igrp proto' is bogus");
6255 /* NOTREACHED */
6256
6257 case Q_PIM:
6258 bpf_error(cstate, "'pim proto' is bogus");
6259 /* NOTREACHED */
6260
6261 case Q_VRRP:
6262 bpf_error(cstate, "'vrrp proto' is bogus");
6263 /* NOTREACHED */
6264
6265 case Q_CARP:
6266 bpf_error(cstate, "'carp proto' is bogus");
6267 /* NOTREACHED */
6268
6269 case Q_IPV6:
6270 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
6271 #ifndef CHASE_CHAIN
6272 /*
6273 * Also check for a fragment header before the final
6274 * header.
6275 */
6276 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
6277 b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, (bpf_int32)v);
6278 gen_and(b2, b1);
6279 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)v);
6280 gen_or(b2, b1);
6281 #else
6282 b1 = gen_protochain(cstate, v, Q_IPV6);
6283 #endif
6284 gen_and(b0, b1);
6285 return b1;
6286
6287 case Q_ICMPV6:
6288 bpf_error(cstate, "'icmp6 proto' is bogus");
6289
6290 case Q_AH:
6291 bpf_error(cstate, "'ah proto' is bogus");
6292
6293 case Q_ESP:
6294 bpf_error(cstate, "'ah proto' is bogus");
6295
6296 case Q_STP:
6297 bpf_error(cstate, "'stp proto' is bogus");
6298
6299 case Q_IPX:
6300 bpf_error(cstate, "'ipx proto' is bogus");
6301
6302 case Q_NETBEUI:
6303 bpf_error(cstate, "'netbeui proto' is bogus");
6304
6305 case Q_RADIO:
6306 bpf_error(cstate, "'radio proto' is bogus");
6307
6308 default:
6309 abort();
6310 /* NOTREACHED */
6311 }
6312 /* NOTREACHED */
6313 }
6314
6315 struct block *
gen_scode(compiler_state_t * cstate,const char * name,struct qual q)6316 gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
6317 {
6318 int proto = q.proto;
6319 int dir = q.dir;
6320 int tproto;
6321 u_char *eaddr;
6322 bpf_u_int32 mask, addr;
6323 struct addrinfo *res, *res0;
6324 struct sockaddr_in *sin4;
6325 #ifdef INET6
6326 int tproto6;
6327 struct sockaddr_in6 *sin6;
6328 struct in6_addr mask128;
6329 #endif /*INET6*/
6330 struct block *b, *tmp;
6331 int port, real_proto;
6332 int port1, port2;
6333
6334 switch (q.addr) {
6335
6336 case Q_NET:
6337 addr = pcap_nametonetaddr(name);
6338 if (addr == 0)
6339 bpf_error(cstate, "unknown network '%s'", name);
6340 /* Left justify network addr and calculate its network mask */
6341 mask = 0xffffffff;
6342 while (addr && (addr & 0xff000000) == 0) {
6343 addr <<= 8;
6344 mask <<= 8;
6345 }
6346 return gen_host(cstate, addr, mask, proto, dir, q.addr);
6347
6348 case Q_DEFAULT:
6349 case Q_HOST:
6350 if (proto == Q_LINK) {
6351 switch (cstate->linktype) {
6352
6353 case DLT_EN10MB:
6354 case DLT_NETANALYZER:
6355 case DLT_NETANALYZER_TRANSPARENT:
6356 eaddr = pcap_ether_hostton(name);
6357 if (eaddr == NULL)
6358 bpf_error(cstate,
6359 "unknown ether host '%s'", name);
6360 tmp = gen_prevlinkhdr_check(cstate);
6361 b = gen_ehostop(cstate, eaddr, dir);
6362 if (tmp != NULL)
6363 gen_and(tmp, b);
6364 free(eaddr);
6365 return b;
6366
6367 case DLT_FDDI:
6368 eaddr = pcap_ether_hostton(name);
6369 if (eaddr == NULL)
6370 bpf_error(cstate,
6371 "unknown FDDI host '%s'", name);
6372 b = gen_fhostop(cstate, eaddr, dir);
6373 free(eaddr);
6374 return b;
6375
6376 case DLT_IEEE802:
6377 eaddr = pcap_ether_hostton(name);
6378 if (eaddr == NULL)
6379 bpf_error(cstate,
6380 "unknown token ring host '%s'", name);
6381 b = gen_thostop(cstate, eaddr, dir);
6382 free(eaddr);
6383 return b;
6384
6385 case DLT_IEEE802_11:
6386 case DLT_PRISM_HEADER:
6387 case DLT_IEEE802_11_RADIO_AVS:
6388 case DLT_IEEE802_11_RADIO:
6389 case DLT_PPI:
6390 eaddr = pcap_ether_hostton(name);
6391 if (eaddr == NULL)
6392 bpf_error(cstate,
6393 "unknown 802.11 host '%s'", name);
6394 b = gen_wlanhostop(cstate, eaddr, dir);
6395 free(eaddr);
6396 return b;
6397
6398 case DLT_IP_OVER_FC:
6399 eaddr = pcap_ether_hostton(name);
6400 if (eaddr == NULL)
6401 bpf_error(cstate,
6402 "unknown Fibre Channel host '%s'", name);
6403 b = gen_ipfchostop(cstate, eaddr, dir);
6404 free(eaddr);
6405 return b;
6406 }
6407
6408 bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
6409 } else if (proto == Q_DECNET) {
6410 unsigned short dn_addr;
6411
6412 if (!__pcap_nametodnaddr(name, &dn_addr)) {
6413 #ifdef DECNETLIB
6414 bpf_error(cstate, "unknown decnet host name '%s'\n", name);
6415 #else
6416 bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n",
6417 name);
6418 #endif
6419 }
6420 /*
6421 * I don't think DECNET hosts can be multihomed, so
6422 * there is no need to build up a list of addresses
6423 */
6424 return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr));
6425 } else {
6426 #ifdef INET6
6427 memset(&mask128, 0xff, sizeof(mask128));
6428 #endif
6429 res0 = res = pcap_nametoaddrinfo(name);
6430 if (res == NULL)
6431 bpf_error(cstate, "unknown host '%s'", name);
6432 cstate->ai = res;
6433 b = tmp = NULL;
6434 tproto = proto;
6435 #ifdef INET6
6436 tproto6 = proto;
6437 #endif
6438 if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
6439 tproto == Q_DEFAULT) {
6440 tproto = Q_IP;
6441 #ifdef INET6
6442 tproto6 = Q_IPV6;
6443 #endif
6444 }
6445 for (res = res0; res; res = res->ai_next) {
6446 switch (res->ai_family) {
6447 case AF_INET:
6448 #ifdef INET6
6449 if (tproto == Q_IPV6)
6450 continue;
6451 #endif
6452
6453 sin4 = (struct sockaddr_in *)
6454 res->ai_addr;
6455 tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
6456 0xffffffff, tproto, dir, q.addr);
6457 break;
6458 #ifdef INET6
6459 case AF_INET6:
6460 if (tproto6 == Q_IP)
6461 continue;
6462
6463 sin6 = (struct sockaddr_in6 *)
6464 res->ai_addr;
6465 tmp = gen_host6(cstate, &sin6->sin6_addr,
6466 &mask128, tproto6, dir, q.addr);
6467 break;
6468 #endif
6469 default:
6470 continue;
6471 }
6472 if (b)
6473 gen_or(b, tmp);
6474 b = tmp;
6475 }
6476 cstate->ai = NULL;
6477 freeaddrinfo(res0);
6478 if (b == NULL) {
6479 bpf_error(cstate, "unknown host '%s'%s", name,
6480 (proto == Q_DEFAULT)
6481 ? ""
6482 : " for specified address family");
6483 }
6484 return b;
6485 }
6486
6487 case Q_PORT:
6488 if (proto != Q_DEFAULT &&
6489 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6490 bpf_error(cstate, "illegal qualifier of 'port'");
6491 if (pcap_nametoport(name, &port, &real_proto) == 0)
6492 bpf_error(cstate, "unknown port '%s'", name);
6493 if (proto == Q_UDP) {
6494 if (real_proto == IPPROTO_TCP)
6495 bpf_error(cstate, "port '%s' is tcp", name);
6496 else if (real_proto == IPPROTO_SCTP)
6497 bpf_error(cstate, "port '%s' is sctp", name);
6498 else
6499 /* override PROTO_UNDEF */
6500 real_proto = IPPROTO_UDP;
6501 }
6502 if (proto == Q_TCP) {
6503 if (real_proto == IPPROTO_UDP)
6504 bpf_error(cstate, "port '%s' is udp", name);
6505
6506 else if (real_proto == IPPROTO_SCTP)
6507 bpf_error(cstate, "port '%s' is sctp", name);
6508 else
6509 /* override PROTO_UNDEF */
6510 real_proto = IPPROTO_TCP;
6511 }
6512 if (proto == Q_SCTP) {
6513 if (real_proto == IPPROTO_UDP)
6514 bpf_error(cstate, "port '%s' is udp", name);
6515
6516 else if (real_proto == IPPROTO_TCP)
6517 bpf_error(cstate, "port '%s' is tcp", name);
6518 else
6519 /* override PROTO_UNDEF */
6520 real_proto = IPPROTO_SCTP;
6521 }
6522 if (port < 0)
6523 bpf_error(cstate, "illegal port number %d < 0", port);
6524 if (port > 65535)
6525 bpf_error(cstate, "illegal port number %d > 65535", port);
6526 b = gen_port(cstate, port, real_proto, dir);
6527 gen_or(gen_port6(cstate, port, real_proto, dir), b);
6528 return b;
6529
6530 case Q_PORTRANGE:
6531 if (proto != Q_DEFAULT &&
6532 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6533 bpf_error(cstate, "illegal qualifier of 'portrange'");
6534 if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
6535 bpf_error(cstate, "unknown port in range '%s'", name);
6536 if (proto == Q_UDP) {
6537 if (real_proto == IPPROTO_TCP)
6538 bpf_error(cstate, "port in range '%s' is tcp", name);
6539 else if (real_proto == IPPROTO_SCTP)
6540 bpf_error(cstate, "port in range '%s' is sctp", name);
6541 else
6542 /* override PROTO_UNDEF */
6543 real_proto = IPPROTO_UDP;
6544 }
6545 if (proto == Q_TCP) {
6546 if (real_proto == IPPROTO_UDP)
6547 bpf_error(cstate, "port in range '%s' is udp", name);
6548 else if (real_proto == IPPROTO_SCTP)
6549 bpf_error(cstate, "port in range '%s' is sctp", name);
6550 else
6551 /* override PROTO_UNDEF */
6552 real_proto = IPPROTO_TCP;
6553 }
6554 if (proto == Q_SCTP) {
6555 if (real_proto == IPPROTO_UDP)
6556 bpf_error(cstate, "port in range '%s' is udp", name);
6557 else if (real_proto == IPPROTO_TCP)
6558 bpf_error(cstate, "port in range '%s' is tcp", name);
6559 else
6560 /* override PROTO_UNDEF */
6561 real_proto = IPPROTO_SCTP;
6562 }
6563 if (port1 < 0)
6564 bpf_error(cstate, "illegal port number %d < 0", port1);
6565 if (port1 > 65535)
6566 bpf_error(cstate, "illegal port number %d > 65535", port1);
6567 if (port2 < 0)
6568 bpf_error(cstate, "illegal port number %d < 0", port2);
6569 if (port2 > 65535)
6570 bpf_error(cstate, "illegal port number %d > 65535", port2);
6571
6572 b = gen_portrange(cstate, port1, port2, real_proto, dir);
6573 gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
6574 return b;
6575
6576 case Q_GATEWAY:
6577 #ifndef INET6
6578 eaddr = pcap_ether_hostton(name);
6579 if (eaddr == NULL)
6580 bpf_error(cstate, "unknown ether host: %s", name);
6581
6582 res = pcap_nametoaddrinfo(name);
6583 cstate->ai = res;
6584 if (res == NULL)
6585 bpf_error(cstate, "unknown host '%s'", name);
6586 b = gen_gateway(cstate, eaddr, res, proto, dir);
6587 cstate->ai = NULL;
6588 freeaddrinfo(res);
6589 if (b == NULL)
6590 bpf_error(cstate, "unknown host '%s'", name);
6591 return b;
6592 #else
6593 bpf_error(cstate, "'gateway' not supported in this configuration");
6594 #endif /*INET6*/
6595
6596 case Q_PROTO:
6597 real_proto = lookup_proto(cstate, name, proto);
6598 if (real_proto >= 0)
6599 return gen_proto(cstate, real_proto, proto, dir);
6600 else
6601 bpf_error(cstate, "unknown protocol: %s", name);
6602
6603 case Q_PROTOCHAIN:
6604 real_proto = lookup_proto(cstate, name, proto);
6605 if (real_proto >= 0)
6606 return gen_protochain(cstate, real_proto, proto, dir);
6607 else
6608 bpf_error(cstate, "unknown protocol: %s", name);
6609
6610 case Q_UNDEF:
6611 syntax(cstate);
6612 /* NOTREACHED */
6613 }
6614 abort();
6615 /* NOTREACHED */
6616 }
6617
6618 struct block *
gen_mcode(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)6619 gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
6620 unsigned int masklen, struct qual q)
6621 {
6622 register int nlen, mlen;
6623 bpf_u_int32 n, m;
6624
6625 nlen = __pcap_atoin(s1, &n);
6626 /* Promote short ipaddr */
6627 n <<= 32 - nlen;
6628
6629 if (s2 != NULL) {
6630 mlen = __pcap_atoin(s2, &m);
6631 /* Promote short ipaddr */
6632 m <<= 32 - mlen;
6633 if ((n & ~m) != 0)
6634 bpf_error(cstate, "non-network bits set in \"%s mask %s\"",
6635 s1, s2);
6636 } else {
6637 /* Convert mask len to mask */
6638 if (masklen > 32)
6639 bpf_error(cstate, "mask length must be <= 32");
6640 if (masklen == 0) {
6641 /*
6642 * X << 32 is not guaranteed by C to be 0; it's
6643 * undefined.
6644 */
6645 m = 0;
6646 } else
6647 m = 0xffffffff << (32 - masklen);
6648 if ((n & ~m) != 0)
6649 bpf_error(cstate, "non-network bits set in \"%s/%d\"",
6650 s1, masklen);
6651 }
6652
6653 switch (q.addr) {
6654
6655 case Q_NET:
6656 return gen_host(cstate, n, m, q.proto, q.dir, q.addr);
6657
6658 default:
6659 bpf_error(cstate, "Mask syntax for networks only");
6660 /* NOTREACHED */
6661 }
6662 /* NOTREACHED */
6663 }
6664
6665 struct block *
gen_ncode(compiler_state_t * cstate,const char * s,bpf_u_int32 v,struct qual q)6666 gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
6667 {
6668 bpf_u_int32 mask;
6669 int proto = q.proto;
6670 int dir = q.dir;
6671 register int vlen;
6672
6673 if (s == NULL)
6674 vlen = 32;
6675 else if (q.proto == Q_DECNET) {
6676 vlen = __pcap_atodn(s, &v);
6677 if (vlen == 0)
6678 bpf_error(cstate, "malformed decnet address '%s'", s);
6679 } else
6680 vlen = __pcap_atoin(s, &v);
6681
6682 switch (q.addr) {
6683
6684 case Q_DEFAULT:
6685 case Q_HOST:
6686 case Q_NET:
6687 if (proto == Q_DECNET)
6688 return gen_host(cstate, v, 0, proto, dir, q.addr);
6689 else if (proto == Q_LINK) {
6690 bpf_error(cstate, "illegal link layer address");
6691 } else {
6692 mask = 0xffffffff;
6693 if (s == NULL && q.addr == Q_NET) {
6694 /* Promote short net number */
6695 while (v && (v & 0xff000000) == 0) {
6696 v <<= 8;
6697 mask <<= 8;
6698 }
6699 } else {
6700 /* Promote short ipaddr */
6701 v <<= 32 - vlen;
6702 mask <<= 32 - vlen ;
6703 }
6704 return gen_host(cstate, v, mask, proto, dir, q.addr);
6705 }
6706
6707 case Q_PORT:
6708 if (proto == Q_UDP)
6709 proto = IPPROTO_UDP;
6710 else if (proto == Q_TCP)
6711 proto = IPPROTO_TCP;
6712 else if (proto == Q_SCTP)
6713 proto = IPPROTO_SCTP;
6714 else if (proto == Q_DEFAULT)
6715 proto = PROTO_UNDEF;
6716 else
6717 bpf_error(cstate, "illegal qualifier of 'port'");
6718
6719 if (v > 65535)
6720 bpf_error(cstate, "illegal port number %u > 65535", v);
6721
6722 {
6723 struct block *b;
6724 b = gen_port(cstate, (int)v, proto, dir);
6725 gen_or(gen_port6(cstate, (int)v, proto, dir), b);
6726 return b;
6727 }
6728
6729 case Q_PORTRANGE:
6730 if (proto == Q_UDP)
6731 proto = IPPROTO_UDP;
6732 else if (proto == Q_TCP)
6733 proto = IPPROTO_TCP;
6734 else if (proto == Q_SCTP)
6735 proto = IPPROTO_SCTP;
6736 else if (proto == Q_DEFAULT)
6737 proto = PROTO_UNDEF;
6738 else
6739 bpf_error(cstate, "illegal qualifier of 'portrange'");
6740
6741 if (v > 65535)
6742 bpf_error(cstate, "illegal port number %u > 65535", v);
6743
6744 {
6745 struct block *b;
6746 b = gen_portrange(cstate, (int)v, (int)v, proto, dir);
6747 gen_or(gen_portrange6(cstate, (int)v, (int)v, proto, dir), b);
6748 return b;
6749 }
6750
6751 case Q_GATEWAY:
6752 bpf_error(cstate, "'gateway' requires a name");
6753 /* NOTREACHED */
6754
6755 case Q_PROTO:
6756 return gen_proto(cstate, (int)v, proto, dir);
6757
6758 case Q_PROTOCHAIN:
6759 return gen_protochain(cstate, (int)v, proto, dir);
6760
6761 case Q_UNDEF:
6762 syntax(cstate);
6763 /* NOTREACHED */
6764
6765 default:
6766 abort();
6767 /* NOTREACHED */
6768 }
6769 /* NOTREACHED */
6770 }
6771
6772 #ifdef INET6
6773 struct block *
gen_mcode6(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)6774 gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
6775 unsigned int masklen, struct qual q)
6776 {
6777 struct addrinfo *res;
6778 struct in6_addr *addr;
6779 struct in6_addr mask;
6780 struct block *b;
6781 uint32_t *a, *m;
6782
6783 if (s2)
6784 bpf_error(cstate, "no mask %s supported", s2);
6785
6786 res = pcap_nametoaddrinfo(s1);
6787 if (!res)
6788 bpf_error(cstate, "invalid ip6 address %s", s1);
6789 cstate->ai = res;
6790 if (res->ai_next)
6791 bpf_error(cstate, "%s resolved to multiple address", s1);
6792 addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
6793
6794 if (sizeof(mask) * 8 < masklen)
6795 bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
6796 memset(&mask, 0, sizeof(mask));
6797 memset(&mask, 0xff, masklen / 8);
6798 if (masklen % 8) {
6799 mask.s6_addr[masklen / 8] =
6800 (0xff << (8 - masklen % 8)) & 0xff;
6801 }
6802
6803 a = (uint32_t *)addr;
6804 m = (uint32_t *)&mask;
6805 if ((a[0] & ~m[0]) || (a[1] & ~m[1])
6806 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
6807 bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
6808 }
6809
6810 switch (q.addr) {
6811
6812 case Q_DEFAULT:
6813 case Q_HOST:
6814 if (masklen != 128)
6815 bpf_error(cstate, "Mask syntax for networks only");
6816 /* FALLTHROUGH */
6817
6818 case Q_NET:
6819 b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
6820 cstate->ai = NULL;
6821 freeaddrinfo(res);
6822 return b;
6823
6824 default:
6825 bpf_error(cstate, "invalid qualifier against IPv6 address");
6826 /* NOTREACHED */
6827 }
6828 }
6829 #endif /*INET6*/
6830
6831 struct block *
gen_ecode(compiler_state_t * cstate,const u_char * eaddr,struct qual q)6832 gen_ecode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
6833 {
6834 struct block *b, *tmp;
6835
6836 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
6837 switch (cstate->linktype) {
6838 case DLT_EN10MB:
6839 case DLT_NETANALYZER:
6840 case DLT_NETANALYZER_TRANSPARENT:
6841 tmp = gen_prevlinkhdr_check(cstate);
6842 b = gen_ehostop(cstate, eaddr, (int)q.dir);
6843 if (tmp != NULL)
6844 gen_and(tmp, b);
6845 return b;
6846 case DLT_FDDI:
6847 return gen_fhostop(cstate, eaddr, (int)q.dir);
6848 case DLT_IEEE802:
6849 return gen_thostop(cstate, eaddr, (int)q.dir);
6850 case DLT_IEEE802_11:
6851 case DLT_PRISM_HEADER:
6852 case DLT_IEEE802_11_RADIO_AVS:
6853 case DLT_IEEE802_11_RADIO:
6854 case DLT_PPI:
6855 return gen_wlanhostop(cstate, eaddr, (int)q.dir);
6856 case DLT_IP_OVER_FC:
6857 return gen_ipfchostop(cstate, eaddr, (int)q.dir);
6858 default:
6859 bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
6860 break;
6861 }
6862 }
6863 bpf_error(cstate, "ethernet address used in non-ether expression");
6864 /* NOTREACHED */
6865 }
6866
6867 void
sappend(struct slist * s0,struct slist * s1)6868 sappend(struct slist *s0, struct slist *s1)
6869 {
6870 /*
6871 * This is definitely not the best way to do this, but the
6872 * lists will rarely get long.
6873 */
6874 while (s0->next)
6875 s0 = s0->next;
6876 s0->next = s1;
6877 }
6878
6879 static struct slist *
xfer_to_x(compiler_state_t * cstate,struct arth * a)6880 xfer_to_x(compiler_state_t *cstate, struct arth *a)
6881 {
6882 struct slist *s;
6883
6884 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
6885 s->s.k = a->regno;
6886 return s;
6887 }
6888
6889 static struct slist *
xfer_to_a(compiler_state_t * cstate,struct arth * a)6890 xfer_to_a(compiler_state_t *cstate, struct arth *a)
6891 {
6892 struct slist *s;
6893
6894 s = new_stmt(cstate, BPF_LD|BPF_MEM);
6895 s->s.k = a->regno;
6896 return s;
6897 }
6898
6899 /*
6900 * Modify "index" to use the value stored into its register as an
6901 * offset relative to the beginning of the header for the protocol
6902 * "proto", and allocate a register and put an item "size" bytes long
6903 * (1, 2, or 4) at that offset into that register, making it the register
6904 * for "index".
6905 */
6906 struct arth *
gen_load(compiler_state_t * cstate,int proto,struct arth * inst,int size)6907 gen_load(compiler_state_t *cstate, int proto, struct arth *inst, int size)
6908 {
6909 struct slist *s, *tmp;
6910 struct block *b;
6911 int regno = alloc_reg(cstate);
6912
6913 free_reg(cstate, inst->regno);
6914 switch (size) {
6915
6916 default:
6917 bpf_error(cstate, "data size must be 1, 2, or 4");
6918
6919 case 1:
6920 size = BPF_B;
6921 break;
6922
6923 case 2:
6924 size = BPF_H;
6925 break;
6926
6927 case 4:
6928 size = BPF_W;
6929 break;
6930 }
6931 switch (proto) {
6932 default:
6933 bpf_error(cstate, "unsupported index operation");
6934
6935 case Q_RADIO:
6936 /*
6937 * The offset is relative to the beginning of the packet
6938 * data, if we have a radio header. (If we don't, this
6939 * is an error.)
6940 */
6941 if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS &&
6942 cstate->linktype != DLT_IEEE802_11_RADIO &&
6943 cstate->linktype != DLT_PRISM_HEADER)
6944 bpf_error(cstate, "radio information not present in capture");
6945
6946 /*
6947 * Load into the X register the offset computed into the
6948 * register specified by "index".
6949 */
6950 s = xfer_to_x(cstate, inst);
6951
6952 /*
6953 * Load the item at that offset.
6954 */
6955 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6956 sappend(s, tmp);
6957 sappend(inst->s, s);
6958 break;
6959
6960 case Q_LINK:
6961 /*
6962 * The offset is relative to the beginning of
6963 * the link-layer header.
6964 *
6965 * XXX - what about ATM LANE? Should the index be
6966 * relative to the beginning of the AAL5 frame, so
6967 * that 0 refers to the beginning of the LE Control
6968 * field, or relative to the beginning of the LAN
6969 * frame, so that 0 refers, for Ethernet LANE, to
6970 * the beginning of the destination address?
6971 */
6972 s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr);
6973
6974 /*
6975 * If "s" is non-null, it has code to arrange that the
6976 * X register contains the length of the prefix preceding
6977 * the link-layer header. Add to it the offset computed
6978 * into the register specified by "index", and move that
6979 * into the X register. Otherwise, just load into the X
6980 * register the offset computed into the register specified
6981 * by "index".
6982 */
6983 if (s != NULL) {
6984 sappend(s, xfer_to_a(cstate, inst));
6985 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
6986 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
6987 } else
6988 s = xfer_to_x(cstate, inst);
6989
6990 /*
6991 * Load the item at the sum of the offset we've put in the
6992 * X register and the offset of the start of the link
6993 * layer header (which is 0 if the radio header is
6994 * variable-length; that header length is what we put
6995 * into the X register and then added to the index).
6996 */
6997 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
6998 tmp->s.k = cstate->off_linkhdr.constant_part;
6999 sappend(s, tmp);
7000 sappend(inst->s, s);
7001 break;
7002
7003 case Q_IP:
7004 case Q_ARP:
7005 case Q_RARP:
7006 case Q_ATALK:
7007 case Q_DECNET:
7008 case Q_SCA:
7009 case Q_LAT:
7010 case Q_MOPRC:
7011 case Q_MOPDL:
7012 case Q_IPV6:
7013 /*
7014 * The offset is relative to the beginning of
7015 * the network-layer header.
7016 * XXX - are there any cases where we want
7017 * cstate->off_nl_nosnap?
7018 */
7019 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7020
7021 /*
7022 * If "s" is non-null, it has code to arrange that the
7023 * X register contains the variable part of the offset
7024 * of the link-layer payload. Add to it the offset
7025 * computed into the register specified by "index",
7026 * and move that into the X register. Otherwise, just
7027 * load into the X register the offset computed into
7028 * the register specified by "index".
7029 */
7030 if (s != NULL) {
7031 sappend(s, xfer_to_a(cstate, inst));
7032 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7033 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7034 } else
7035 s = xfer_to_x(cstate, inst);
7036
7037 /*
7038 * Load the item at the sum of the offset we've put in the
7039 * X register, the offset of the start of the network
7040 * layer header from the beginning of the link-layer
7041 * payload, and the constant part of the offset of the
7042 * start of the link-layer payload.
7043 */
7044 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7045 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7046 sappend(s, tmp);
7047 sappend(inst->s, s);
7048
7049 /*
7050 * Do the computation only if the packet contains
7051 * the protocol in question.
7052 */
7053 b = gen_proto_abbrev(cstate, proto);
7054 if (inst->b)
7055 gen_and(inst->b, b);
7056 inst->b = b;
7057 break;
7058
7059 case Q_SCTP:
7060 case Q_TCP:
7061 case Q_UDP:
7062 case Q_ICMP:
7063 case Q_IGMP:
7064 case Q_IGRP:
7065 case Q_PIM:
7066 case Q_VRRP:
7067 case Q_CARP:
7068 /*
7069 * The offset is relative to the beginning of
7070 * the transport-layer header.
7071 *
7072 * Load the X register with the length of the IPv4 header
7073 * (plus the offset of the link-layer header, if it's
7074 * a variable-length header), in bytes.
7075 *
7076 * XXX - are there any cases where we want
7077 * cstate->off_nl_nosnap?
7078 * XXX - we should, if we're built with
7079 * IPv6 support, generate code to load either
7080 * IPv4, IPv6, or both, as appropriate.
7081 */
7082 s = gen_loadx_iphdrlen(cstate);
7083
7084 /*
7085 * The X register now contains the sum of the variable
7086 * part of the offset of the link-layer payload and the
7087 * length of the network-layer header.
7088 *
7089 * Load into the A register the offset relative to
7090 * the beginning of the transport layer header,
7091 * add the X register to that, move that to the
7092 * X register, and load with an offset from the
7093 * X register equal to the sum of the constant part of
7094 * the offset of the link-layer payload and the offset,
7095 * relative to the beginning of the link-layer payload,
7096 * of the network-layer header.
7097 */
7098 sappend(s, xfer_to_a(cstate, inst));
7099 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7100 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7101 sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size));
7102 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7103 sappend(inst->s, s);
7104
7105 /*
7106 * Do the computation only if the packet contains
7107 * the protocol in question - which is true only
7108 * if this is an IP datagram and is the first or
7109 * only fragment of that datagram.
7110 */
7111 gen_and(gen_proto_abbrev(cstate, proto), b = gen_ipfrag(cstate));
7112 if (inst->b)
7113 gen_and(inst->b, b);
7114 gen_and(gen_proto_abbrev(cstate, Q_IP), b);
7115 inst->b = b;
7116 break;
7117 case Q_ICMPV6:
7118 /*
7119 * Do the computation only if the packet contains
7120 * the protocol in question.
7121 */
7122 b = gen_proto_abbrev(cstate, Q_IPV6);
7123 if (inst->b) {
7124 gen_and(inst->b, b);
7125 }
7126 inst->b = b;
7127
7128 /*
7129 * Check if we have an icmp6 next header
7130 */
7131 b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58);
7132 if (inst->b) {
7133 gen_and(inst->b, b);
7134 }
7135 inst->b = b;
7136
7137
7138 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7139 /*
7140 * If "s" is non-null, it has code to arrange that the
7141 * X register contains the variable part of the offset
7142 * of the link-layer payload. Add to it the offset
7143 * computed into the register specified by "index",
7144 * and move that into the X register. Otherwise, just
7145 * load into the X register the offset computed into
7146 * the register specified by "index".
7147 */
7148 if (s != NULL) {
7149 sappend(s, xfer_to_a(cstate, inst));
7150 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7151 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7152 } else {
7153 s = xfer_to_x(cstate, inst);
7154 }
7155
7156 /*
7157 * Load the item at the sum of the offset we've put in the
7158 * X register, the offset of the start of the network
7159 * layer header from the beginning of the link-layer
7160 * payload, and the constant part of the offset of the
7161 * start of the link-layer payload.
7162 */
7163 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7164 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 40;
7165
7166 sappend(s, tmp);
7167 sappend(inst->s, s);
7168
7169 break;
7170 }
7171 inst->regno = regno;
7172 s = new_stmt(cstate, BPF_ST);
7173 s->s.k = regno;
7174 sappend(inst->s, s);
7175
7176 return inst;
7177 }
7178
7179 struct block *
gen_relation(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1,int reversed)7180 gen_relation(compiler_state_t *cstate, int code, struct arth *a0,
7181 struct arth *a1, int reversed)
7182 {
7183 struct slist *s0, *s1, *s2;
7184 struct block *b, *tmp;
7185
7186 s0 = xfer_to_x(cstate, a1);
7187 s1 = xfer_to_a(cstate, a0);
7188 if (code == BPF_JEQ) {
7189 s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X);
7190 b = new_block(cstate, JMP(code));
7191 sappend(s1, s2);
7192 }
7193 else
7194 b = new_block(cstate, BPF_JMP|code|BPF_X);
7195 if (reversed)
7196 gen_not(b);
7197
7198 sappend(s0, s1);
7199 sappend(a1->s, s0);
7200 sappend(a0->s, a1->s);
7201
7202 b->stmts = a0->s;
7203
7204 free_reg(cstate, a0->regno);
7205 free_reg(cstate, a1->regno);
7206
7207 /* 'and' together protocol checks */
7208 if (a0->b) {
7209 if (a1->b) {
7210 gen_and(a0->b, tmp = a1->b);
7211 }
7212 else
7213 tmp = a0->b;
7214 } else
7215 tmp = a1->b;
7216
7217 if (tmp)
7218 gen_and(tmp, b);
7219
7220 return b;
7221 }
7222
7223 struct arth *
gen_loadlen(compiler_state_t * cstate)7224 gen_loadlen(compiler_state_t *cstate)
7225 {
7226 int regno = alloc_reg(cstate);
7227 struct arth *a = (struct arth *)newchunk(cstate, sizeof(*a));
7228 struct slist *s;
7229
7230 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7231 s->next = new_stmt(cstate, BPF_ST);
7232 s->next->s.k = regno;
7233 a->s = s;
7234 a->regno = regno;
7235
7236 return a;
7237 }
7238
7239 struct arth *
gen_loadi(compiler_state_t * cstate,int val)7240 gen_loadi(compiler_state_t *cstate, int val)
7241 {
7242 struct arth *a;
7243 struct slist *s;
7244 int reg;
7245
7246 a = (struct arth *)newchunk(cstate, sizeof(*a));
7247
7248 reg = alloc_reg(cstate);
7249
7250 s = new_stmt(cstate, BPF_LD|BPF_IMM);
7251 s->s.k = val;
7252 s->next = new_stmt(cstate, BPF_ST);
7253 s->next->s.k = reg;
7254 a->s = s;
7255 a->regno = reg;
7256
7257 return a;
7258 }
7259
7260 struct arth *
gen_neg(compiler_state_t * cstate,struct arth * a)7261 gen_neg(compiler_state_t *cstate, struct arth *a)
7262 {
7263 struct slist *s;
7264
7265 s = xfer_to_a(cstate, a);
7266 sappend(a->s, s);
7267 s = new_stmt(cstate, BPF_ALU|BPF_NEG);
7268 s->s.k = 0;
7269 sappend(a->s, s);
7270 s = new_stmt(cstate, BPF_ST);
7271 s->s.k = a->regno;
7272 sappend(a->s, s);
7273
7274 return a;
7275 }
7276
7277 struct arth *
gen_arth(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1)7278 gen_arth(compiler_state_t *cstate, int code, struct arth *a0,
7279 struct arth *a1)
7280 {
7281 struct slist *s0, *s1, *s2;
7282
7283 /*
7284 * Disallow division by, or modulus by, zero; we do this here
7285 * so that it gets done even if the optimizer is disabled.
7286 */
7287 if (code == BPF_DIV) {
7288 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7289 bpf_error(cstate, "division by zero");
7290 } else if (code == BPF_MOD) {
7291 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7292 bpf_error(cstate, "modulus by zero");
7293 }
7294 s0 = xfer_to_x(cstate, a1);
7295 s1 = xfer_to_a(cstate, a0);
7296 s2 = new_stmt(cstate, BPF_ALU|BPF_X|code);
7297
7298 sappend(s1, s2);
7299 sappend(s0, s1);
7300 sappend(a1->s, s0);
7301 sappend(a0->s, a1->s);
7302
7303 free_reg(cstate, a0->regno);
7304 free_reg(cstate, a1->regno);
7305
7306 s0 = new_stmt(cstate, BPF_ST);
7307 a0->regno = s0->s.k = alloc_reg(cstate);
7308 sappend(a0->s, s0);
7309
7310 return a0;
7311 }
7312
7313 /*
7314 * Initialize the table of used registers and the current register.
7315 */
7316 static void
init_regs(compiler_state_t * cstate)7317 init_regs(compiler_state_t *cstate)
7318 {
7319 cstate->curreg = 0;
7320 memset(cstate->regused, 0, sizeof cstate->regused);
7321 }
7322
7323 /*
7324 * Return the next free register.
7325 */
7326 static int
alloc_reg(compiler_state_t * cstate)7327 alloc_reg(compiler_state_t *cstate)
7328 {
7329 int n = BPF_MEMWORDS;
7330
7331 while (--n >= 0) {
7332 if (cstate->regused[cstate->curreg])
7333 cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS;
7334 else {
7335 cstate->regused[cstate->curreg] = 1;
7336 return cstate->curreg;
7337 }
7338 }
7339 bpf_error(cstate, "too many registers needed to evaluate expression");
7340 /* NOTREACHED */
7341 }
7342
7343 /*
7344 * Return a register to the table so it can
7345 * be used later.
7346 */
7347 static void
free_reg(compiler_state_t * cstate,int n)7348 free_reg(compiler_state_t *cstate, int n)
7349 {
7350 cstate->regused[n] = 0;
7351 }
7352
7353 static struct block *
gen_len(compiler_state_t * cstate,int jmp,int n)7354 gen_len(compiler_state_t *cstate, int jmp, int n)
7355 {
7356 struct slist *s;
7357 struct block *b;
7358
7359 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7360 b = new_block(cstate, JMP(jmp));
7361 b->stmts = s;
7362 b->s.k = n;
7363
7364 return b;
7365 }
7366
7367 struct block *
gen_greater(compiler_state_t * cstate,int n)7368 gen_greater(compiler_state_t *cstate, int n)
7369 {
7370 return gen_len(cstate, BPF_JGE, n);
7371 }
7372
7373 /*
7374 * Actually, this is less than or equal.
7375 */
7376 struct block *
gen_less(compiler_state_t * cstate,int n)7377 gen_less(compiler_state_t *cstate, int n)
7378 {
7379 struct block *b;
7380
7381 b = gen_len(cstate, BPF_JGT, n);
7382 gen_not(b);
7383
7384 return b;
7385 }
7386
7387 /*
7388 * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
7389 * the beginning of the link-layer header.
7390 * XXX - that means you can't test values in the radiotap header, but
7391 * as that header is difficult if not impossible to parse generally
7392 * without a loop, that might not be a severe problem. A new keyword
7393 * "radio" could be added for that, although what you'd really want
7394 * would be a way of testing particular radio header values, which
7395 * would generate code appropriate to the radio header in question.
7396 */
7397 struct block *
gen_byteop(compiler_state_t * cstate,int op,int idx,int val)7398 gen_byteop(compiler_state_t *cstate, int op, int idx, int val)
7399 {
7400 struct block *b;
7401 struct slist *s;
7402
7403 switch (op) {
7404 default:
7405 abort();
7406
7407 case '=':
7408 return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7409
7410 case '<':
7411 b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7412 return b;
7413
7414 case '>':
7415 b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7416 return b;
7417
7418 case '|':
7419 s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K);
7420 break;
7421
7422 case '&':
7423 s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
7424 break;
7425 }
7426 s->s.k = val;
7427 b = new_block(cstate, JMP(BPF_JEQ));
7428 b->stmts = s;
7429 gen_not(b);
7430
7431 return b;
7432 }
7433
7434 static const u_char abroadcast[] = { 0x0 };
7435
7436 struct block *
gen_broadcast(compiler_state_t * cstate,int proto)7437 gen_broadcast(compiler_state_t *cstate, int proto)
7438 {
7439 bpf_u_int32 hostmask;
7440 struct block *b0, *b1, *b2;
7441 static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
7442
7443 switch (proto) {
7444
7445 case Q_DEFAULT:
7446 case Q_LINK:
7447 switch (cstate->linktype) {
7448 case DLT_ARCNET:
7449 case DLT_ARCNET_LINUX:
7450 return gen_ahostop(cstate, abroadcast, Q_DST);
7451 case DLT_EN10MB:
7452 case DLT_NETANALYZER:
7453 case DLT_NETANALYZER_TRANSPARENT:
7454 b1 = gen_prevlinkhdr_check(cstate);
7455 b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
7456 if (b1 != NULL)
7457 gen_and(b1, b0);
7458 return b0;
7459 case DLT_FDDI:
7460 return gen_fhostop(cstate, ebroadcast, Q_DST);
7461 case DLT_IEEE802:
7462 return gen_thostop(cstate, ebroadcast, Q_DST);
7463 case DLT_IEEE802_11:
7464 case DLT_PRISM_HEADER:
7465 case DLT_IEEE802_11_RADIO_AVS:
7466 case DLT_IEEE802_11_RADIO:
7467 case DLT_PPI:
7468 return gen_wlanhostop(cstate, ebroadcast, Q_DST);
7469 case DLT_IP_OVER_FC:
7470 return gen_ipfchostop(cstate, ebroadcast, Q_DST);
7471 default:
7472 bpf_error(cstate, "not a broadcast link");
7473 }
7474 break;
7475
7476 case Q_IP:
7477 /*
7478 * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
7479 * as an indication that we don't know the netmask, and fail
7480 * in that case.
7481 */
7482 if (cstate->netmask == PCAP_NETMASK_UNKNOWN)
7483 bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported");
7484 b0 = gen_linktype(cstate, ETHERTYPE_IP);
7485 hostmask = ~cstate->netmask;
7486 b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, (bpf_int32)0, hostmask);
7487 b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W,
7488 (bpf_int32)(~0 & hostmask), hostmask);
7489 gen_or(b1, b2);
7490 gen_and(b0, b2);
7491 return b2;
7492 }
7493 bpf_error(cstate, "only link-layer/IP broadcast filters supported");
7494 /* NOTREACHED */
7495 }
7496
7497 /*
7498 * Generate code to test the low-order bit of a MAC address (that's
7499 * the bottom bit of the *first* byte).
7500 */
7501 static struct block *
gen_mac_multicast(compiler_state_t * cstate,int offset)7502 gen_mac_multicast(compiler_state_t *cstate, int offset)
7503 {
7504 register struct block *b0;
7505 register struct slist *s;
7506
7507 /* link[offset] & 1 != 0 */
7508 s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B);
7509 b0 = new_block(cstate, JMP(BPF_JSET));
7510 b0->s.k = 1;
7511 b0->stmts = s;
7512 return b0;
7513 }
7514
7515 struct block *
gen_multicast(compiler_state_t * cstate,int proto)7516 gen_multicast(compiler_state_t *cstate, int proto)
7517 {
7518 register struct block *b0, *b1, *b2;
7519 register struct slist *s;
7520
7521 switch (proto) {
7522
7523 case Q_DEFAULT:
7524 case Q_LINK:
7525 switch (cstate->linktype) {
7526 case DLT_ARCNET:
7527 case DLT_ARCNET_LINUX:
7528 /* all ARCnet multicasts use the same address */
7529 return gen_ahostop(cstate, abroadcast, Q_DST);
7530 case DLT_EN10MB:
7531 case DLT_NETANALYZER:
7532 case DLT_NETANALYZER_TRANSPARENT:
7533 b1 = gen_prevlinkhdr_check(cstate);
7534 /* ether[0] & 1 != 0 */
7535 b0 = gen_mac_multicast(cstate, 0);
7536 if (b1 != NULL)
7537 gen_and(b1, b0);
7538 return b0;
7539 case DLT_FDDI:
7540 /*
7541 * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
7542 *
7543 * XXX - was that referring to bit-order issues?
7544 */
7545 /* fddi[1] & 1 != 0 */
7546 return gen_mac_multicast(cstate, 1);
7547 case DLT_IEEE802:
7548 /* tr[2] & 1 != 0 */
7549 return gen_mac_multicast(cstate, 2);
7550 case DLT_IEEE802_11:
7551 case DLT_PRISM_HEADER:
7552 case DLT_IEEE802_11_RADIO_AVS:
7553 case DLT_IEEE802_11_RADIO:
7554 case DLT_PPI:
7555 /*
7556 * Oh, yuk.
7557 *
7558 * For control frames, there is no DA.
7559 *
7560 * For management frames, DA is at an
7561 * offset of 4 from the beginning of
7562 * the packet.
7563 *
7564 * For data frames, DA is at an offset
7565 * of 4 from the beginning of the packet
7566 * if To DS is clear and at an offset of
7567 * 16 from the beginning of the packet
7568 * if To DS is set.
7569 */
7570
7571 /*
7572 * Generate the tests to be done for data frames.
7573 *
7574 * First, check for To DS set, i.e. "link[1] & 0x01".
7575 */
7576 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7577 b1 = new_block(cstate, JMP(BPF_JSET));
7578 b1->s.k = 0x01; /* To DS */
7579 b1->stmts = s;
7580
7581 /*
7582 * If To DS is set, the DA is at 16.
7583 */
7584 b0 = gen_mac_multicast(cstate, 16);
7585 gen_and(b1, b0);
7586
7587 /*
7588 * Now, check for To DS not set, i.e. check
7589 * "!(link[1] & 0x01)".
7590 */
7591 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
7592 b2 = new_block(cstate, JMP(BPF_JSET));
7593 b2->s.k = 0x01; /* To DS */
7594 b2->stmts = s;
7595 gen_not(b2);
7596
7597 /*
7598 * If To DS is not set, the DA is at 4.
7599 */
7600 b1 = gen_mac_multicast(cstate, 4);
7601 gen_and(b2, b1);
7602
7603 /*
7604 * Now OR together the last two checks. That gives
7605 * the complete set of checks for data frames.
7606 */
7607 gen_or(b1, b0);
7608
7609 /*
7610 * Now check for a data frame.
7611 * I.e, check "link[0] & 0x08".
7612 */
7613 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7614 b1 = new_block(cstate, JMP(BPF_JSET));
7615 b1->s.k = 0x08;
7616 b1->stmts = s;
7617
7618 /*
7619 * AND that with the checks done for data frames.
7620 */
7621 gen_and(b1, b0);
7622
7623 /*
7624 * If the high-order bit of the type value is 0, this
7625 * is a management frame.
7626 * I.e, check "!(link[0] & 0x08)".
7627 */
7628 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7629 b2 = new_block(cstate, JMP(BPF_JSET));
7630 b2->s.k = 0x08;
7631 b2->stmts = s;
7632 gen_not(b2);
7633
7634 /*
7635 * For management frames, the DA is at 4.
7636 */
7637 b1 = gen_mac_multicast(cstate, 4);
7638 gen_and(b2, b1);
7639
7640 /*
7641 * OR that with the checks done for data frames.
7642 * That gives the checks done for management and
7643 * data frames.
7644 */
7645 gen_or(b1, b0);
7646
7647 /*
7648 * If the low-order bit of the type value is 1,
7649 * this is either a control frame or a frame
7650 * with a reserved type, and thus not a
7651 * frame with an SA.
7652 *
7653 * I.e., check "!(link[0] & 0x04)".
7654 */
7655 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
7656 b1 = new_block(cstate, JMP(BPF_JSET));
7657 b1->s.k = 0x04;
7658 b1->stmts = s;
7659 gen_not(b1);
7660
7661 /*
7662 * AND that with the checks for data and management
7663 * frames.
7664 */
7665 gen_and(b1, b0);
7666 return b0;
7667 case DLT_IP_OVER_FC:
7668 b0 = gen_mac_multicast(cstate, 2);
7669 return b0;
7670 default:
7671 break;
7672 }
7673 /* Link not known to support multicasts */
7674 break;
7675
7676 case Q_IP:
7677 b0 = gen_linktype(cstate, ETHERTYPE_IP);
7678 b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, (bpf_int32)224);
7679 gen_and(b0, b1);
7680 return b1;
7681
7682 case Q_IPV6:
7683 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
7684 b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, (bpf_int32)255);
7685 gen_and(b0, b1);
7686 return b1;
7687 }
7688 bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
7689 /* NOTREACHED */
7690 }
7691
7692 /*
7693 * Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
7694 * Outbound traffic is sent by this machine, while inbound traffic is
7695 * sent by a remote machine (and may include packets destined for a
7696 * unicast or multicast link-layer address we are not subscribing to).
7697 * These are the same definitions implemented by pcap_setdirection().
7698 * Capturing only unicast traffic destined for this host is probably
7699 * better accomplished using a higher-layer filter.
7700 */
7701 struct block *
gen_inbound(compiler_state_t * cstate,int dir)7702 gen_inbound(compiler_state_t *cstate, int dir)
7703 {
7704 register struct block *b0;
7705
7706 /*
7707 * Only some data link types support inbound/outbound qualifiers.
7708 */
7709 switch (cstate->linktype) {
7710 case DLT_SLIP:
7711 b0 = gen_relation(cstate, BPF_JEQ,
7712 gen_load(cstate, Q_LINK, gen_loadi(cstate, 0), 1),
7713 gen_loadi(cstate, 0),
7714 dir);
7715 break;
7716
7717 case DLT_IPNET:
7718 if (dir) {
7719 /* match outgoing packets */
7720 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND);
7721 } else {
7722 /* match incoming packets */
7723 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND);
7724 }
7725 break;
7726
7727 case DLT_LINUX_SLL:
7728 /* match outgoing packets */
7729 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING);
7730 if (!dir) {
7731 /* to filter on inbound traffic, invert the match */
7732 gen_not(b0);
7733 }
7734 break;
7735
7736 #ifdef HAVE_NET_PFVAR_H
7737 case DLT_PFLOG:
7738 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
7739 (bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
7740 break;
7741 #endif
7742
7743 case DLT_PPP_PPPD:
7744 if (dir) {
7745 /* match outgoing packets */
7746 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT);
7747 } else {
7748 /* match incoming packets */
7749 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN);
7750 }
7751 break;
7752
7753 case DLT_JUNIPER_MFR:
7754 case DLT_JUNIPER_MLFR:
7755 case DLT_JUNIPER_MLPPP:
7756 case DLT_JUNIPER_ATM1:
7757 case DLT_JUNIPER_ATM2:
7758 case DLT_JUNIPER_PPPOE:
7759 case DLT_JUNIPER_PPPOE_ATM:
7760 case DLT_JUNIPER_GGSN:
7761 case DLT_JUNIPER_ES:
7762 case DLT_JUNIPER_MONITOR:
7763 case DLT_JUNIPER_SERVICES:
7764 case DLT_JUNIPER_ETHER:
7765 case DLT_JUNIPER_PPP:
7766 case DLT_JUNIPER_FRELAY:
7767 case DLT_JUNIPER_CHDLC:
7768 case DLT_JUNIPER_VP:
7769 case DLT_JUNIPER_ST:
7770 case DLT_JUNIPER_ISM:
7771 case DLT_JUNIPER_VS:
7772 case DLT_JUNIPER_SRX_E2E:
7773 case DLT_JUNIPER_FIBRECHANNEL:
7774 case DLT_JUNIPER_ATM_CEMIC:
7775
7776 /* juniper flags (including direction) are stored
7777 * the byte after the 3-byte magic number */
7778 if (dir) {
7779 /* match outgoing packets */
7780 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01);
7781 } else {
7782 /* match incoming packets */
7783 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01);
7784 }
7785 break;
7786
7787 default:
7788 /*
7789 * If we have packet meta-data indicating a direction,
7790 * and that metadata can be checked by BPF code, check
7791 * it. Otherwise, give up, as this link-layer type has
7792 * nothing in the packet data.
7793 *
7794 * Currently, the only platform where a BPF filter can
7795 * check that metadata is Linux with the in-kernel
7796 * BPF interpreter. If other packet capture mechanisms
7797 * and BPF filters also supported this, it would be
7798 * nice. It would be even better if they made that
7799 * metadata available so that we could provide it
7800 * with newer capture APIs, allowing it to be saved
7801 * in pcapng files.
7802 */
7803 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
7804 /*
7805 * This is Linux with PF_PACKET support.
7806 * If this is a *live* capture, we can look at
7807 * special meta-data in the filter expression;
7808 * if it's a savefile, we can't.
7809 */
7810 if (cstate->bpf_pcap->rfile != NULL) {
7811 /* We have a FILE *, so this is a savefile */
7812 bpf_error(cstate, "inbound/outbound not supported on linktype %d when reading savefiles",
7813 cstate->linktype);
7814 b0 = NULL;
7815 /* NOTREACHED */
7816 }
7817 /* match outgoing packets */
7818 b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
7819 PACKET_OUTGOING);
7820 if (!dir) {
7821 /* to filter on inbound traffic, invert the match */
7822 gen_not(b0);
7823 }
7824 #else /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7825 bpf_error(cstate, "inbound/outbound not supported on linktype %d",
7826 cstate->linktype);
7827 /* NOTREACHED */
7828 #endif /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
7829 }
7830 return (b0);
7831 }
7832
7833 #ifdef HAVE_NET_PFVAR_H
7834 /* PF firewall log matched interface */
7835 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname)7836 gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
7837 {
7838 struct block *b0;
7839 u_int len, off;
7840
7841 if (cstate->linktype != DLT_PFLOG) {
7842 bpf_error(cstate, "ifname supported only on PF linktype");
7843 /* NOTREACHED */
7844 }
7845 len = sizeof(((struct pfloghdr *)0)->ifname);
7846 off = offsetof(struct pfloghdr, ifname);
7847 if (strlen(ifname) >= len) {
7848 bpf_error(cstate, "ifname interface names can only be %d characters",
7849 len-1);
7850 /* NOTREACHED */
7851 }
7852 b0 = gen_bcmp(cstate, OR_LINKHDR, off, strlen(ifname), (const u_char *)ifname);
7853 return (b0);
7854 }
7855
7856 /* PF firewall log ruleset name */
7857 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset)7858 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
7859 {
7860 struct block *b0;
7861
7862 if (cstate->linktype != DLT_PFLOG) {
7863 bpf_error(cstate, "ruleset supported only on PF linktype");
7864 /* NOTREACHED */
7865 }
7866
7867 if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
7868 bpf_error(cstate, "ruleset names can only be %ld characters",
7869 (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
7870 /* NOTREACHED */
7871 }
7872
7873 b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
7874 strlen(ruleset), (const u_char *)ruleset);
7875 return (b0);
7876 }
7877
7878 /* PF firewall log rule number */
7879 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr)7880 gen_pf_rnr(compiler_state_t *cstate, int rnr)
7881 {
7882 struct block *b0;
7883
7884 if (cstate->linktype != DLT_PFLOG) {
7885 bpf_error(cstate, "rnr supported only on PF linktype");
7886 /* NOTREACHED */
7887 }
7888
7889 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
7890 (bpf_int32)rnr);
7891 return (b0);
7892 }
7893
7894 /* PF firewall log sub-rule number */
7895 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr)7896 gen_pf_srnr(compiler_state_t *cstate, int srnr)
7897 {
7898 struct block *b0;
7899
7900 if (cstate->linktype != DLT_PFLOG) {
7901 bpf_error(cstate, "srnr supported only on PF linktype");
7902 /* NOTREACHED */
7903 }
7904
7905 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
7906 (bpf_int32)srnr);
7907 return (b0);
7908 }
7909
7910 /* PF firewall log reason code */
7911 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason)7912 gen_pf_reason(compiler_state_t *cstate, int reason)
7913 {
7914 struct block *b0;
7915
7916 if (cstate->linktype != DLT_PFLOG) {
7917 bpf_error(cstate, "reason supported only on PF linktype");
7918 /* NOTREACHED */
7919 }
7920
7921 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
7922 (bpf_int32)reason);
7923 return (b0);
7924 }
7925
7926 /* PF firewall log action */
7927 struct block *
gen_pf_action(compiler_state_t * cstate,int action)7928 gen_pf_action(compiler_state_t *cstate, int action)
7929 {
7930 struct block *b0;
7931
7932 if (cstate->linktype != DLT_PFLOG) {
7933 bpf_error(cstate, "action supported only on PF linktype");
7934 /* NOTREACHED */
7935 }
7936
7937 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
7938 (bpf_int32)action);
7939 return (b0);
7940 }
7941 #else /* !HAVE_NET_PFVAR_H */
7942 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname _U_)7943 gen_pf_ifname(compiler_state_t *cstate, const char *ifname _U_)
7944 {
7945 bpf_error(cstate, "libpcap was compiled without pf support");
7946 /* NOTREACHED */
7947 }
7948
7949 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset _U_)7950 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset _U_)
7951 {
7952 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7953 /* NOTREACHED */
7954 }
7955
7956 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr _U_)7957 gen_pf_rnr(compiler_state_t *cstate, int rnr _U_)
7958 {
7959 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7960 /* NOTREACHED */
7961 }
7962
7963 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr _U_)7964 gen_pf_srnr(compiler_state_t *cstate, int srnr _U_)
7965 {
7966 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7967 /* NOTREACHED */
7968 }
7969
7970 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason _U_)7971 gen_pf_reason(compiler_state_t *cstate, int reason _U_)
7972 {
7973 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7974 /* NOTREACHED */
7975 }
7976
7977 struct block *
gen_pf_action(compiler_state_t * cstate,int action _U_)7978 gen_pf_action(compiler_state_t *cstate, int action _U_)
7979 {
7980 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
7981 /* NOTREACHED */
7982 }
7983 #endif /* HAVE_NET_PFVAR_H */
7984
7985 /* IEEE 802.11 wireless header */
7986 struct block *
gen_p80211_type(compiler_state_t * cstate,int type,int mask)7987 gen_p80211_type(compiler_state_t *cstate, int type, int mask)
7988 {
7989 struct block *b0;
7990
7991 switch (cstate->linktype) {
7992
7993 case DLT_IEEE802_11:
7994 case DLT_PRISM_HEADER:
7995 case DLT_IEEE802_11_RADIO_AVS:
7996 case DLT_IEEE802_11_RADIO:
7997 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, (bpf_int32)type,
7998 (bpf_int32)mask);
7999 break;
8000
8001 default:
8002 bpf_error(cstate, "802.11 link-layer types supported only on 802.11");
8003 /* NOTREACHED */
8004 }
8005
8006 return (b0);
8007 }
8008
8009 struct block *
gen_p80211_fcdir(compiler_state_t * cstate,int fcdir)8010 gen_p80211_fcdir(compiler_state_t *cstate, int fcdir)
8011 {
8012 struct block *b0;
8013
8014 switch (cstate->linktype) {
8015
8016 case DLT_IEEE802_11:
8017 case DLT_PRISM_HEADER:
8018 case DLT_IEEE802_11_RADIO_AVS:
8019 case DLT_IEEE802_11_RADIO:
8020 break;
8021
8022 default:
8023 bpf_error(cstate, "frame direction supported only with 802.11 headers");
8024 /* NOTREACHED */
8025 }
8026
8027 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, (bpf_int32)fcdir,
8028 (bpf_u_int32)IEEE80211_FC1_DIR_MASK);
8029
8030 return (b0);
8031 }
8032
8033 struct block *
gen_acode(compiler_state_t * cstate,const u_char * eaddr,struct qual q)8034 gen_acode(compiler_state_t *cstate, const u_char *eaddr, struct qual q)
8035 {
8036 switch (cstate->linktype) {
8037
8038 case DLT_ARCNET:
8039 case DLT_ARCNET_LINUX:
8040 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
8041 q.proto == Q_LINK)
8042 return (gen_ahostop(cstate, eaddr, (int)q.dir));
8043 else {
8044 bpf_error(cstate, "ARCnet address used in non-arc expression");
8045 /* NOTREACHED */
8046 }
8047 break;
8048
8049 default:
8050 bpf_error(cstate, "aid supported only on ARCnet");
8051 /* NOTREACHED */
8052 }
8053 }
8054
8055 static struct block *
gen_ahostop(compiler_state_t * cstate,const u_char * eaddr,int dir)8056 gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
8057 {
8058 register struct block *b0, *b1;
8059
8060 switch (dir) {
8061 /* src comes first, different from Ethernet */
8062 case Q_SRC:
8063 return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr);
8064
8065 case Q_DST:
8066 return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr);
8067
8068 case Q_AND:
8069 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8070 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8071 gen_and(b0, b1);
8072 return b1;
8073
8074 case Q_DEFAULT:
8075 case Q_OR:
8076 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8077 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8078 gen_or(b0, b1);
8079 return b1;
8080
8081 case Q_ADDR1:
8082 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
8083 break;
8084
8085 case Q_ADDR2:
8086 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
8087 break;
8088
8089 case Q_ADDR3:
8090 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
8091 break;
8092
8093 case Q_ADDR4:
8094 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
8095 break;
8096
8097 case Q_RA:
8098 bpf_error(cstate, "'ra' is only supported on 802.11");
8099 break;
8100
8101 case Q_TA:
8102 bpf_error(cstate, "'ta' is only supported on 802.11");
8103 break;
8104 }
8105 abort();
8106 /* NOTREACHED */
8107 }
8108
8109 static struct block *
gen_vlan_tpid_test(compiler_state_t * cstate)8110 gen_vlan_tpid_test(compiler_state_t *cstate)
8111 {
8112 struct block *b0, *b1;
8113
8114 /* check for VLAN, including QinQ */
8115 b0 = gen_linktype(cstate, ETHERTYPE_8021Q);
8116 b1 = gen_linktype(cstate, ETHERTYPE_8021AD);
8117 gen_or(b0,b1);
8118 b0 = b1;
8119 b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ);
8120 gen_or(b0,b1);
8121
8122 return b1;
8123 }
8124
8125 static struct block *
gen_vlan_vid_test(compiler_state_t * cstate,int vlan_num)8126 gen_vlan_vid_test(compiler_state_t *cstate, int vlan_num)
8127 {
8128 return gen_mcmp(cstate, OR_LINKPL, 0, BPF_H, (bpf_int32)vlan_num, 0x0fff);
8129 }
8130
8131 static struct block *
gen_vlan_no_bpf_extensions(compiler_state_t * cstate,int vlan_num)8132 gen_vlan_no_bpf_extensions(compiler_state_t *cstate, int vlan_num)
8133 {
8134 struct block *b0, *b1;
8135
8136 b0 = gen_vlan_tpid_test(cstate);
8137
8138 if (vlan_num >= 0) {
8139 b1 = gen_vlan_vid_test(cstate, vlan_num);
8140 gen_and(b0, b1);
8141 b0 = b1;
8142 }
8143
8144 /*
8145 * Both payload and link header type follow the VLAN tags so that
8146 * both need to be updated.
8147 */
8148 cstate->off_linkpl.constant_part += 4;
8149 cstate->off_linktype.constant_part += 4;
8150
8151 return b0;
8152 }
8153
8154 #if defined(SKF_AD_VLAN_TAG_PRESENT)
8155 /* add v to variable part of off */
8156 static void
gen_vlan_vloffset_add(compiler_state_t * cstate,bpf_abs_offset * off,int v,struct slist * s)8157 gen_vlan_vloffset_add(compiler_state_t *cstate, bpf_abs_offset *off, int v, struct slist *s)
8158 {
8159 struct slist *s2;
8160
8161 if (!off->is_variable)
8162 off->is_variable = 1;
8163 if (off->reg == -1)
8164 off->reg = alloc_reg(cstate);
8165
8166 s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
8167 s2->s.k = off->reg;
8168 sappend(s, s2);
8169 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
8170 s2->s.k = v;
8171 sappend(s, s2);
8172 s2 = new_stmt(cstate, BPF_ST);
8173 s2->s.k = off->reg;
8174 sappend(s, s2);
8175 }
8176
8177 /*
8178 * patch block b_tpid (VLAN TPID test) to update variable parts of link payload
8179 * and link type offsets first
8180 */
8181 static void
gen_vlan_patch_tpid_test(compiler_state_t * cstate,struct block * b_tpid)8182 gen_vlan_patch_tpid_test(compiler_state_t *cstate, struct block *b_tpid)
8183 {
8184 struct slist s;
8185
8186 /* offset determined at run time, shift variable part */
8187 s.next = NULL;
8188 cstate->is_vlan_vloffset = 1;
8189 gen_vlan_vloffset_add(cstate, &cstate->off_linkpl, 4, &s);
8190 gen_vlan_vloffset_add(cstate, &cstate->off_linktype, 4, &s);
8191
8192 /* we get a pointer to a chain of or-ed blocks, patch first of them */
8193 sappend(s.next, b_tpid->head->stmts);
8194 b_tpid->head->stmts = s.next;
8195 }
8196
8197 /*
8198 * patch block b_vid (VLAN id test) to load VID value either from packet
8199 * metadata (using BPF extensions) if SKF_AD_VLAN_TAG_PRESENT is true
8200 */
8201 static void
gen_vlan_patch_vid_test(compiler_state_t * cstate,struct block * b_vid)8202 gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
8203 {
8204 struct slist *s, *s2, *sjeq;
8205 unsigned cnt;
8206
8207 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8208 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8209
8210 /* true -> next instructions, false -> beginning of b_vid */
8211 sjeq = new_stmt(cstate, JMP(BPF_JEQ));
8212 sjeq->s.k = 1;
8213 sjeq->s.jf = b_vid->stmts;
8214 sappend(s, sjeq);
8215
8216 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8217 s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
8218 sappend(s, s2);
8219 sjeq->s.jt = s2;
8220
8221 /* jump to the test in b_vid (bypass loading VID from packet data) */
8222 cnt = 0;
8223 for (s2 = b_vid->stmts; s2; s2 = s2->next)
8224 cnt++;
8225 s2 = new_stmt(cstate, JMP(BPF_JA));
8226 s2->s.k = cnt;
8227 sappend(s, s2);
8228
8229 /* insert our statements at the beginning of b_vid */
8230 sappend(s, b_vid->stmts);
8231 b_vid->stmts = s;
8232 }
8233
8234 /*
8235 * Generate check for "vlan" or "vlan <id>" on systems with support for BPF
8236 * extensions. Even if kernel supports VLAN BPF extensions, (outermost) VLAN
8237 * tag can be either in metadata or in packet data; therefore if the
8238 * SKF_AD_VLAN_TAG_PRESENT test is negative, we need to check link
8239 * header for VLAN tag. As the decision is done at run time, we need
8240 * update variable part of the offsets
8241 */
8242 static struct block *
gen_vlan_bpf_extensions(compiler_state_t * cstate,int vlan_num)8243 gen_vlan_bpf_extensions(compiler_state_t *cstate, int vlan_num)
8244 {
8245 struct block *b0, *b_tpid, *b_vid = NULL;
8246 struct slist *s;
8247
8248 /* generate new filter code based on extracting packet
8249 * metadata */
8250 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8251 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8252
8253 b0 = new_block(cstate, JMP(BPF_JEQ));
8254 b0->stmts = s;
8255 b0->s.k = 1;
8256
8257 /*
8258 * This is tricky. We need to insert the statements updating variable
8259 * parts of offsets before the the traditional TPID and VID tests so
8260 * that they are called whenever SKF_AD_VLAN_TAG_PRESENT fails but
8261 * we do not want this update to affect those checks. That's why we
8262 * generate both test blocks first and insert the statements updating
8263 * variable parts of both offsets after that. This wouldn't work if
8264 * there already were variable length link header when entering this
8265 * function but gen_vlan_bpf_extensions() isn't called in that case.
8266 */
8267 b_tpid = gen_vlan_tpid_test(cstate);
8268 if (vlan_num >= 0)
8269 b_vid = gen_vlan_vid_test(cstate, vlan_num);
8270
8271 gen_vlan_patch_tpid_test(cstate, b_tpid);
8272 gen_or(b0, b_tpid);
8273 b0 = b_tpid;
8274
8275 if (vlan_num >= 0) {
8276 gen_vlan_patch_vid_test(cstate, b_vid);
8277 gen_and(b0, b_vid);
8278 b0 = b_vid;
8279 }
8280
8281 return b0;
8282 }
8283 #endif
8284
8285 /*
8286 * support IEEE 802.1Q VLAN trunk over ethernet
8287 */
8288 struct block *
gen_vlan(compiler_state_t * cstate,int vlan_num)8289 gen_vlan(compiler_state_t *cstate, int vlan_num)
8290 {
8291 struct block *b0;
8292
8293 /* can't check for VLAN-encapsulated packets inside MPLS */
8294 if (cstate->label_stack_depth > 0)
8295 bpf_error(cstate, "no VLAN match after MPLS");
8296
8297 /*
8298 * Check for a VLAN packet, and then change the offsets to point
8299 * to the type and data fields within the VLAN packet. Just
8300 * increment the offsets, so that we can support a hierarchy, e.g.
8301 * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
8302 * VLAN 100.
8303 *
8304 * XXX - this is a bit of a kludge. If we were to split the
8305 * compiler into a parser that parses an expression and
8306 * generates an expression tree, and a code generator that
8307 * takes an expression tree (which could come from our
8308 * parser or from some other parser) and generates BPF code,
8309 * we could perhaps make the offsets parameters of routines
8310 * and, in the handler for an "AND" node, pass to subnodes
8311 * other than the VLAN node the adjusted offsets.
8312 *
8313 * This would mean that "vlan" would, instead of changing the
8314 * behavior of *all* tests after it, change only the behavior
8315 * of tests ANDed with it. That would change the documented
8316 * semantics of "vlan", which might break some expressions.
8317 * However, it would mean that "(vlan and ip) or ip" would check
8318 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8319 * checking only for VLAN-encapsulated IP, so that could still
8320 * be considered worth doing; it wouldn't break expressions
8321 * that are of the form "vlan and ..." or "vlan N and ...",
8322 * which I suspect are the most common expressions involving
8323 * "vlan". "vlan or ..." doesn't necessarily do what the user
8324 * would really want, now, as all the "or ..." tests would
8325 * be done assuming a VLAN, even though the "or" could be viewed
8326 * as meaning "or, if this isn't a VLAN packet...".
8327 */
8328 switch (cstate->linktype) {
8329
8330 case DLT_EN10MB:
8331 case DLT_NETANALYZER:
8332 case DLT_NETANALYZER_TRANSPARENT:
8333 #if defined(SKF_AD_VLAN_TAG_PRESENT)
8334 /* Verify that this is the outer part of the packet and
8335 * not encapsulated somehow. */
8336 if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable &&
8337 cstate->off_linkhdr.constant_part ==
8338 cstate->off_outermostlinkhdr.constant_part) {
8339 /*
8340 * Do we need special VLAN handling?
8341 */
8342 if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
8343 b0 = gen_vlan_bpf_extensions(cstate, vlan_num);
8344 else
8345 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8346 } else
8347 #endif
8348 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8349 break;
8350
8351 case DLT_IEEE802_11:
8352 case DLT_PRISM_HEADER:
8353 case DLT_IEEE802_11_RADIO_AVS:
8354 case DLT_IEEE802_11_RADIO:
8355 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num);
8356 break;
8357
8358 default:
8359 bpf_error(cstate, "no VLAN support for data link type %d",
8360 cstate->linktype);
8361 /*NOTREACHED*/
8362 }
8363
8364 cstate->vlan_stack_depth++;
8365
8366 return (b0);
8367 }
8368
8369 /*
8370 * support for MPLS
8371 */
8372 struct block *
gen_mpls(compiler_state_t * cstate,int label_num)8373 gen_mpls(compiler_state_t *cstate, int label_num)
8374 {
8375 struct block *b0, *b1;
8376
8377 if (cstate->label_stack_depth > 0) {
8378 /* just match the bottom-of-stack bit clear */
8379 b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01);
8380 } else {
8381 /*
8382 * We're not in an MPLS stack yet, so check the link-layer
8383 * type against MPLS.
8384 */
8385 switch (cstate->linktype) {
8386
8387 case DLT_C_HDLC: /* fall through */
8388 case DLT_EN10MB:
8389 case DLT_NETANALYZER:
8390 case DLT_NETANALYZER_TRANSPARENT:
8391 b0 = gen_linktype(cstate, ETHERTYPE_MPLS);
8392 break;
8393
8394 case DLT_PPP:
8395 b0 = gen_linktype(cstate, PPP_MPLS_UCAST);
8396 break;
8397
8398 /* FIXME add other DLT_s ...
8399 * for Frame-Relay/and ATM this may get messy due to SNAP headers
8400 * leave it for now */
8401
8402 default:
8403 bpf_error(cstate, "no MPLS support for data link type %d",
8404 cstate->linktype);
8405 /*NOTREACHED*/
8406 break;
8407 }
8408 }
8409
8410 /* If a specific MPLS label is requested, check it */
8411 if (label_num >= 0) {
8412 label_num = label_num << 12; /* label is shifted 12 bits on the wire */
8413 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, (bpf_int32)label_num,
8414 0xfffff000); /* only compare the first 20 bits */
8415 gen_and(b0, b1);
8416 b0 = b1;
8417 }
8418
8419 /*
8420 * Change the offsets to point to the type and data fields within
8421 * the MPLS packet. Just increment the offsets, so that we
8422 * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
8423 * capture packets with an outer label of 100000 and an inner
8424 * label of 1024.
8425 *
8426 * Increment the MPLS stack depth as well; this indicates that
8427 * we're checking MPLS-encapsulated headers, to make sure higher
8428 * level code generators don't try to match against IP-related
8429 * protocols such as Q_ARP, Q_RARP etc.
8430 *
8431 * XXX - this is a bit of a kludge. See comments in gen_vlan().
8432 */
8433 cstate->off_nl_nosnap += 4;
8434 cstate->off_nl += 4;
8435 cstate->label_stack_depth++;
8436 return (b0);
8437 }
8438
8439 /*
8440 * Support PPPOE discovery and session.
8441 */
8442 struct block *
gen_pppoed(compiler_state_t * cstate)8443 gen_pppoed(compiler_state_t *cstate)
8444 {
8445 /* check for PPPoE discovery */
8446 return gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOED);
8447 }
8448
8449 struct block *
gen_pppoes(compiler_state_t * cstate,int sess_num)8450 gen_pppoes(compiler_state_t *cstate, int sess_num)
8451 {
8452 struct block *b0, *b1;
8453
8454 /*
8455 * Test against the PPPoE session link-layer type.
8456 */
8457 b0 = gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOES);
8458
8459 /* If a specific session is requested, check PPPoE session id */
8460 if (sess_num >= 0) {
8461 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W,
8462 (bpf_int32)sess_num, 0x0000ffff);
8463 gen_and(b0, b1);
8464 b0 = b1;
8465 }
8466
8467 /*
8468 * Change the offsets to point to the type and data fields within
8469 * the PPP packet, and note that this is PPPoE rather than
8470 * raw PPP.
8471 *
8472 * XXX - this is a bit of a kludge. If we were to split the
8473 * compiler into a parser that parses an expression and
8474 * generates an expression tree, and a code generator that
8475 * takes an expression tree (which could come from our
8476 * parser or from some other parser) and generates BPF code,
8477 * we could perhaps make the offsets parameters of routines
8478 * and, in the handler for an "AND" node, pass to subnodes
8479 * other than the PPPoE node the adjusted offsets.
8480 *
8481 * This would mean that "pppoes" would, instead of changing the
8482 * behavior of *all* tests after it, change only the behavior
8483 * of tests ANDed with it. That would change the documented
8484 * semantics of "pppoes", which might break some expressions.
8485 * However, it would mean that "(pppoes and ip) or ip" would check
8486 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8487 * checking only for VLAN-encapsulated IP, so that could still
8488 * be considered worth doing; it wouldn't break expressions
8489 * that are of the form "pppoes and ..." which I suspect are the
8490 * most common expressions involving "pppoes". "pppoes or ..."
8491 * doesn't necessarily do what the user would really want, now,
8492 * as all the "or ..." tests would be done assuming PPPoE, even
8493 * though the "or" could be viewed as meaning "or, if this isn't
8494 * a PPPoE packet...".
8495 *
8496 * The "network-layer" protocol is PPPoE, which has a 6-byte
8497 * PPPoE header, followed by a PPP packet.
8498 *
8499 * There is no HDLC encapsulation for the PPP packet (it's
8500 * encapsulated in PPPoES instead), so the link-layer type
8501 * starts at the first byte of the PPP packet. For PPPoE,
8502 * that offset is relative to the beginning of the total
8503 * link-layer payload, including any 802.2 LLC header, so
8504 * it's 6 bytes past cstate->off_nl.
8505 */
8506 PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable,
8507 cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */
8508 cstate->off_linkpl.reg);
8509
8510 cstate->off_linktype = cstate->off_linkhdr;
8511 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2;
8512
8513 cstate->off_nl = 0;
8514 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
8515
8516 return b0;
8517 }
8518
8519 /* Check that this is Geneve and the VNI is correct if
8520 * specified. Parameterized to handle both IPv4 and IPv6. */
8521 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)8522 gen_geneve_check(compiler_state_t *cstate,
8523 struct block *(*gen_portfn)(compiler_state_t *, int, int, int),
8524 enum e_offrel offrel, int vni)
8525 {
8526 struct block *b0, *b1;
8527
8528 b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST);
8529
8530 /* Check that we are operating on version 0. Otherwise, we
8531 * can't decode the rest of the fields. The version is 2 bits
8532 * in the first byte of the Geneve header. */
8533 b1 = gen_mcmp(cstate, offrel, 8, BPF_B, (bpf_int32)0, 0xc0);
8534 gen_and(b0, b1);
8535 b0 = b1;
8536
8537 if (vni >= 0) {
8538 vni <<= 8; /* VNI is in the upper 3 bytes */
8539 b1 = gen_mcmp(cstate, offrel, 12, BPF_W, (bpf_int32)vni,
8540 0xffffff00);
8541 gen_and(b0, b1);
8542 b0 = b1;
8543 }
8544
8545 return b0;
8546 }
8547
8548 /* The IPv4 and IPv6 Geneve checks need to do two things:
8549 * - Verify that this actually is Geneve with the right VNI.
8550 * - Place the IP header length (plus variable link prefix if
8551 * needed) into register A to be used later to compute
8552 * the inner packet offsets. */
8553 static struct block *
gen_geneve4(compiler_state_t * cstate,int vni)8554 gen_geneve4(compiler_state_t *cstate, int vni)
8555 {
8556 struct block *b0, *b1;
8557 struct slist *s, *s1;
8558
8559 b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni);
8560
8561 /* Load the IP header length into A. */
8562 s = gen_loadx_iphdrlen(cstate);
8563
8564 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8565 sappend(s, s1);
8566
8567 /* Forcibly append these statements to the true condition
8568 * of the protocol check by creating a new block that is
8569 * always true and ANDing them. */
8570 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8571 b1->stmts = s;
8572 b1->s.k = 0;
8573
8574 gen_and(b0, b1);
8575
8576 return b1;
8577 }
8578
8579 static struct block *
gen_geneve6(compiler_state_t * cstate,int vni)8580 gen_geneve6(compiler_state_t *cstate, int vni)
8581 {
8582 struct block *b0, *b1;
8583 struct slist *s, *s1;
8584
8585 b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni);
8586
8587 /* Load the IP header length. We need to account for a
8588 * variable length link prefix if there is one. */
8589 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
8590 if (s) {
8591 s1 = new_stmt(cstate, BPF_LD|BPF_IMM);
8592 s1->s.k = 40;
8593 sappend(s, s1);
8594
8595 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8596 s1->s.k = 0;
8597 sappend(s, s1);
8598 } else {
8599 s = new_stmt(cstate, BPF_LD|BPF_IMM);
8600 s->s.k = 40;
8601 }
8602
8603 /* Forcibly append these statements to the true condition
8604 * of the protocol check by creating a new block that is
8605 * always true and ANDing them. */
8606 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8607 sappend(s, s1);
8608
8609 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8610 b1->stmts = s;
8611 b1->s.k = 0;
8612
8613 gen_and(b0, b1);
8614
8615 return b1;
8616 }
8617
8618 /* We need to store three values based on the Geneve header::
8619 * - The offset of the linktype.
8620 * - The offset of the end of the Geneve header.
8621 * - The offset of the end of the encapsulated MAC header. */
8622 static struct slist *
gen_geneve_offsets(compiler_state_t * cstate)8623 gen_geneve_offsets(compiler_state_t *cstate)
8624 {
8625 struct slist *s, *s1, *s_proto;
8626
8627 /* First we need to calculate the offset of the Geneve header
8628 * itself. This is composed of the IP header previously calculated
8629 * (include any variable link prefix) and stored in A plus the
8630 * fixed sized headers (fixed link prefix, MAC length, and UDP
8631 * header). */
8632 s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8633 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8;
8634
8635 /* Stash this in X since we'll need it later. */
8636 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8637 sappend(s, s1);
8638
8639 /* The EtherType in Geneve is 2 bytes in. Calculate this and
8640 * store it. */
8641 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8642 s1->s.k = 2;
8643 sappend(s, s1);
8644
8645 cstate->off_linktype.reg = alloc_reg(cstate);
8646 cstate->off_linktype.is_variable = 1;
8647 cstate->off_linktype.constant_part = 0;
8648
8649 s1 = new_stmt(cstate, BPF_ST);
8650 s1->s.k = cstate->off_linktype.reg;
8651 sappend(s, s1);
8652
8653 /* Load the Geneve option length and mask and shift to get the
8654 * number of bytes. It is stored in the first byte of the Geneve
8655 * header. */
8656 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
8657 s1->s.k = 0;
8658 sappend(s, s1);
8659
8660 s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
8661 s1->s.k = 0x3f;
8662 sappend(s, s1);
8663
8664 s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
8665 s1->s.k = 4;
8666 sappend(s, s1);
8667
8668 /* Add in the rest of the Geneve base header. */
8669 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8670 s1->s.k = 8;
8671 sappend(s, s1);
8672
8673 /* Add the Geneve header length to its offset and store. */
8674 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
8675 s1->s.k = 0;
8676 sappend(s, s1);
8677
8678 /* Set the encapsulated type as Ethernet. Even though we may
8679 * not actually have Ethernet inside there are two reasons this
8680 * is useful:
8681 * - The linktype field is always in EtherType format regardless
8682 * of whether it is in Geneve or an inner Ethernet frame.
8683 * - The only link layer that we have specific support for is
8684 * Ethernet. We will confirm that the packet actually is
8685 * Ethernet at runtime before executing these checks. */
8686 PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate));
8687
8688 s1 = new_stmt(cstate, BPF_ST);
8689 s1->s.k = cstate->off_linkhdr.reg;
8690 sappend(s, s1);
8691
8692 /* Calculate whether we have an Ethernet header or just raw IP/
8693 * MPLS/etc. If we have Ethernet, advance the end of the MAC offset
8694 * and linktype by 14 bytes so that the network header can be found
8695 * seamlessly. Otherwise, keep what we've calculated already. */
8696
8697 /* We have a bare jmp so we can't use the optimizer. */
8698 cstate->no_optimize = 1;
8699
8700 /* Load the EtherType in the Geneve header, 2 bytes in. */
8701 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H);
8702 s1->s.k = 2;
8703 sappend(s, s1);
8704
8705 /* Load X with the end of the Geneve header. */
8706 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8707 s1->s.k = cstate->off_linkhdr.reg;
8708 sappend(s, s1);
8709
8710 /* Check if the EtherType is Transparent Ethernet Bridging. At the
8711 * end of this check, we should have the total length in X. In
8712 * the non-Ethernet case, it's already there. */
8713 s_proto = new_stmt(cstate, JMP(BPF_JEQ));
8714 s_proto->s.k = ETHERTYPE_TEB;
8715 sappend(s, s_proto);
8716
8717 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
8718 sappend(s, s1);
8719 s_proto->s.jt = s1;
8720
8721 /* Since this is Ethernet, use the EtherType of the payload
8722 * directly as the linktype. Overwrite what we already have. */
8723 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8724 s1->s.k = 12;
8725 sappend(s, s1);
8726
8727 s1 = new_stmt(cstate, BPF_ST);
8728 s1->s.k = cstate->off_linktype.reg;
8729 sappend(s, s1);
8730
8731 /* Advance two bytes further to get the end of the Ethernet
8732 * header. */
8733 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
8734 s1->s.k = 2;
8735 sappend(s, s1);
8736
8737 /* Move the result to X. */
8738 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
8739 sappend(s, s1);
8740
8741 /* Store the final result of our linkpl calculation. */
8742 cstate->off_linkpl.reg = alloc_reg(cstate);
8743 cstate->off_linkpl.is_variable = 1;
8744 cstate->off_linkpl.constant_part = 0;
8745
8746 s1 = new_stmt(cstate, BPF_STX);
8747 s1->s.k = cstate->off_linkpl.reg;
8748 sappend(s, s1);
8749 s_proto->s.jf = s1;
8750
8751 cstate->off_nl = 0;
8752
8753 return s;
8754 }
8755
8756 /* Check to see if this is a Geneve packet. */
8757 struct block *
gen_geneve(compiler_state_t * cstate,int vni)8758 gen_geneve(compiler_state_t *cstate, int vni)
8759 {
8760 struct block *b0, *b1;
8761 struct slist *s;
8762
8763 b0 = gen_geneve4(cstate, vni);
8764 b1 = gen_geneve6(cstate, vni);
8765
8766 gen_or(b0, b1);
8767 b0 = b1;
8768
8769 /* Later filters should act on the payload of the Geneve frame,
8770 * update all of the header pointers. Attach this code so that
8771 * it gets executed in the event that the Geneve filter matches. */
8772 s = gen_geneve_offsets(cstate);
8773
8774 b1 = gen_true(cstate);
8775 sappend(s, b1->stmts);
8776 b1->stmts = s;
8777
8778 gen_and(b0, b1);
8779
8780 cstate->is_geneve = 1;
8781
8782 return b1;
8783 }
8784
8785 /* Check that the encapsulated frame has a link layer header
8786 * for Ethernet filters. */
8787 static struct block *
gen_geneve_ll_check(compiler_state_t * cstate)8788 gen_geneve_ll_check(compiler_state_t *cstate)
8789 {
8790 struct block *b0;
8791 struct slist *s, *s1;
8792
8793 /* The easiest way to see if there is a link layer present
8794 * is to check if the link layer header and payload are not
8795 * the same. */
8796
8797 /* Geneve always generates pure variable offsets so we can
8798 * compare only the registers. */
8799 s = new_stmt(cstate, BPF_LD|BPF_MEM);
8800 s->s.k = cstate->off_linkhdr.reg;
8801
8802 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
8803 s1->s.k = cstate->off_linkpl.reg;
8804 sappend(s, s1);
8805
8806 b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
8807 b0->stmts = s;
8808 b0->s.k = 0;
8809 gen_not(b0);
8810
8811 return b0;
8812 }
8813
8814 struct block *
gen_atmfield_code(compiler_state_t * cstate,int atmfield,bpf_int32 jvalue,bpf_u_int32 jtype,int reverse)8815 gen_atmfield_code(compiler_state_t *cstate, int atmfield, bpf_int32 jvalue,
8816 bpf_u_int32 jtype, int reverse)
8817 {
8818 struct block *b0;
8819
8820 switch (atmfield) {
8821
8822 case A_VPI:
8823 if (!cstate->is_atm)
8824 bpf_error(cstate, "'vpi' supported only on raw ATM");
8825 if (cstate->off_vpi == OFFSET_NOT_SET)
8826 abort();
8827 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffff, jtype,
8828 reverse, jvalue);
8829 break;
8830
8831 case A_VCI:
8832 if (!cstate->is_atm)
8833 bpf_error(cstate, "'vci' supported only on raw ATM");
8834 if (cstate->off_vci == OFFSET_NOT_SET)
8835 abort();
8836 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffff, jtype,
8837 reverse, jvalue);
8838 break;
8839
8840 case A_PROTOTYPE:
8841 if (cstate->off_proto == OFFSET_NOT_SET)
8842 abort(); /* XXX - this isn't on FreeBSD */
8843 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0f, jtype,
8844 reverse, jvalue);
8845 break;
8846
8847 case A_MSGTYPE:
8848 if (cstate->off_payload == OFFSET_NOT_SET)
8849 abort();
8850 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
8851 0xffffffff, jtype, reverse, jvalue);
8852 break;
8853
8854 case A_CALLREFTYPE:
8855 if (!cstate->is_atm)
8856 bpf_error(cstate, "'callref' supported only on raw ATM");
8857 if (cstate->off_proto == OFFSET_NOT_SET)
8858 abort();
8859 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffff,
8860 jtype, reverse, jvalue);
8861 break;
8862
8863 default:
8864 abort();
8865 }
8866 return b0;
8867 }
8868
8869 struct block *
gen_atmtype_abbrev(compiler_state_t * cstate,int type)8870 gen_atmtype_abbrev(compiler_state_t *cstate, int type)
8871 {
8872 struct block *b0, *b1;
8873
8874 switch (type) {
8875
8876 case A_METAC:
8877 /* Get all packets in Meta signalling Circuit */
8878 if (!cstate->is_atm)
8879 bpf_error(cstate, "'metac' supported only on raw ATM");
8880 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8881 b1 = gen_atmfield_code(cstate, A_VCI, 1, BPF_JEQ, 0);
8882 gen_and(b0, b1);
8883 break;
8884
8885 case A_BCC:
8886 /* Get all packets in Broadcast Circuit*/
8887 if (!cstate->is_atm)
8888 bpf_error(cstate, "'bcc' supported only on raw ATM");
8889 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8890 b1 = gen_atmfield_code(cstate, A_VCI, 2, BPF_JEQ, 0);
8891 gen_and(b0, b1);
8892 break;
8893
8894 case A_OAMF4SC:
8895 /* Get all cells in Segment OAM F4 circuit*/
8896 if (!cstate->is_atm)
8897 bpf_error(cstate, "'oam4sc' supported only on raw ATM");
8898 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8899 b1 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
8900 gen_and(b0, b1);
8901 break;
8902
8903 case A_OAMF4EC:
8904 /* Get all cells in End-to-End OAM F4 Circuit*/
8905 if (!cstate->is_atm)
8906 bpf_error(cstate, "'oam4ec' supported only on raw ATM");
8907 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8908 b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
8909 gen_and(b0, b1);
8910 break;
8911
8912 case A_SC:
8913 /* Get all packets in connection Signalling Circuit */
8914 if (!cstate->is_atm)
8915 bpf_error(cstate, "'sc' supported only on raw ATM");
8916 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8917 b1 = gen_atmfield_code(cstate, A_VCI, 5, BPF_JEQ, 0);
8918 gen_and(b0, b1);
8919 break;
8920
8921 case A_ILMIC:
8922 /* Get all packets in ILMI Circuit */
8923 if (!cstate->is_atm)
8924 bpf_error(cstate, "'ilmic' supported only on raw ATM");
8925 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
8926 b1 = gen_atmfield_code(cstate, A_VCI, 16, BPF_JEQ, 0);
8927 gen_and(b0, b1);
8928 break;
8929
8930 case A_LANE:
8931 /* Get all LANE packets */
8932 if (!cstate->is_atm)
8933 bpf_error(cstate, "'lane' supported only on raw ATM");
8934 b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
8935
8936 /*
8937 * Arrange that all subsequent tests assume LANE
8938 * rather than LLC-encapsulated packets, and set
8939 * the offsets appropriately for LANE-encapsulated
8940 * Ethernet.
8941 *
8942 * We assume LANE means Ethernet, not Token Ring.
8943 */
8944 PUSH_LINKHDR(cstate, DLT_EN10MB, 0,
8945 cstate->off_payload + 2, /* Ethernet header */
8946 -1);
8947 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
8948 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* Ethernet */
8949 cstate->off_nl = 0; /* Ethernet II */
8950 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
8951 break;
8952
8953 case A_LLC:
8954 /* Get all LLC-encapsulated packets */
8955 if (!cstate->is_atm)
8956 bpf_error(cstate, "'llc' supported only on raw ATM");
8957 b1 = gen_atmfield_code(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
8958 cstate->linktype = cstate->prevlinktype;
8959 break;
8960
8961 default:
8962 abort();
8963 }
8964 return b1;
8965 }
8966
8967 /*
8968 * Filtering for MTP2 messages based on li value
8969 * FISU, length is null
8970 * LSSU, length is 1 or 2
8971 * MSU, length is 3 or more
8972 * For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits
8973 */
8974 struct block *
gen_mtp2type_abbrev(compiler_state_t * cstate,int type)8975 gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
8976 {
8977 struct block *b0, *b1;
8978
8979 switch (type) {
8980
8981 case M_FISU:
8982 if ( (cstate->linktype != DLT_MTP2) &&
8983 (cstate->linktype != DLT_ERF) &&
8984 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8985 bpf_error(cstate, "'fisu' supported only on MTP2");
8986 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
8987 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
8988 break;
8989
8990 case M_LSSU:
8991 if ( (cstate->linktype != DLT_MTP2) &&
8992 (cstate->linktype != DLT_ERF) &&
8993 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
8994 bpf_error(cstate, "'lssu' supported only on MTP2");
8995 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
8996 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
8997 gen_and(b1, b0);
8998 break;
8999
9000 case M_MSU:
9001 if ( (cstate->linktype != DLT_MTP2) &&
9002 (cstate->linktype != DLT_ERF) &&
9003 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9004 bpf_error(cstate, "'msu' supported only on MTP2");
9005 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
9006 break;
9007
9008 case MH_FISU:
9009 if ( (cstate->linktype != DLT_MTP2) &&
9010 (cstate->linktype != DLT_ERF) &&
9011 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9012 bpf_error(cstate, "'hfisu' supported only on MTP2_HSL");
9013 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
9014 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JEQ, 0, 0);
9015 break;
9016
9017 case MH_LSSU:
9018 if ( (cstate->linktype != DLT_MTP2) &&
9019 (cstate->linktype != DLT_ERF) &&
9020 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9021 bpf_error(cstate, "'hlssu' supported only on MTP2_HSL");
9022 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 1, 0x0100);
9023 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0);
9024 gen_and(b1, b0);
9025 break;
9026
9027 case MH_MSU:
9028 if ( (cstate->linktype != DLT_MTP2) &&
9029 (cstate->linktype != DLT_ERF) &&
9030 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9031 bpf_error(cstate, "'hmsu' supported only on MTP2_HSL");
9032 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0x0100);
9033 break;
9034
9035 default:
9036 abort();
9037 }
9038 return b0;
9039 }
9040
9041 struct block *
gen_mtp3field_code(compiler_state_t * cstate,int mtp3field,bpf_u_int32 jvalue,bpf_u_int32 jtype,int reverse)9042 gen_mtp3field_code(compiler_state_t *cstate, int mtp3field, bpf_u_int32 jvalue,
9043 bpf_u_int32 jtype, int reverse)
9044 {
9045 struct block *b0;
9046 bpf_u_int32 val1 , val2 , val3;
9047 u_int newoff_sio = cstate->off_sio;
9048 u_int newoff_opc = cstate->off_opc;
9049 u_int newoff_dpc = cstate->off_dpc;
9050 u_int newoff_sls = cstate->off_sls;
9051
9052 switch (mtp3field) {
9053
9054 case MH_SIO:
9055 newoff_sio += 3; /* offset for MTP2_HSL */
9056 /* FALLTHROUGH */
9057
9058 case M_SIO:
9059 if (cstate->off_sio == OFFSET_NOT_SET)
9060 bpf_error(cstate, "'sio' supported only on SS7");
9061 /* sio coded on 1 byte so max value 255 */
9062 if(jvalue > 255)
9063 bpf_error(cstate, "sio value %u too big; max value = 255",
9064 jvalue);
9065 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffff,
9066 (u_int)jtype, reverse, (u_int)jvalue);
9067 break;
9068
9069 case MH_OPC:
9070 newoff_opc+=3;
9071 case M_OPC:
9072 if (cstate->off_opc == OFFSET_NOT_SET)
9073 bpf_error(cstate, "'opc' supported only on SS7");
9074 /* opc coded on 14 bits so max value 16383 */
9075 if (jvalue > 16383)
9076 bpf_error(cstate, "opc value %u too big; max value = 16383",
9077 jvalue);
9078 /* the following instructions are made to convert jvalue
9079 * to the form used to write opc in an ss7 message*/
9080 val1 = jvalue & 0x00003c00;
9081 val1 = val1 >>10;
9082 val2 = jvalue & 0x000003fc;
9083 val2 = val2 <<6;
9084 val3 = jvalue & 0x00000003;
9085 val3 = val3 <<22;
9086 jvalue = val1 + val2 + val3;
9087 b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0f,
9088 (u_int)jtype, reverse, (u_int)jvalue);
9089 break;
9090
9091 case MH_DPC:
9092 newoff_dpc += 3;
9093 /* FALLTHROUGH */
9094
9095 case M_DPC:
9096 if (cstate->off_dpc == OFFSET_NOT_SET)
9097 bpf_error(cstate, "'dpc' supported only on SS7");
9098 /* dpc coded on 14 bits so max value 16383 */
9099 if (jvalue > 16383)
9100 bpf_error(cstate, "dpc value %u too big; max value = 16383",
9101 jvalue);
9102 /* the following instructions are made to convert jvalue
9103 * to the forme used to write dpc in an ss7 message*/
9104 val1 = jvalue & 0x000000ff;
9105 val1 = val1 << 24;
9106 val2 = jvalue & 0x00003f00;
9107 val2 = val2 << 8;
9108 jvalue = val1 + val2;
9109 b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000,
9110 (u_int)jtype, reverse, (u_int)jvalue);
9111 break;
9112
9113 case MH_SLS:
9114 newoff_sls+=3;
9115 case M_SLS:
9116 if (cstate->off_sls == OFFSET_NOT_SET)
9117 bpf_error(cstate, "'sls' supported only on SS7");
9118 /* sls coded on 4 bits so max value 15 */
9119 if (jvalue > 15)
9120 bpf_error(cstate, "sls value %u too big; max value = 15",
9121 jvalue);
9122 /* the following instruction is made to convert jvalue
9123 * to the forme used to write sls in an ss7 message*/
9124 jvalue = jvalue << 4;
9125 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0,
9126 (u_int)jtype,reverse, (u_int)jvalue);
9127 break;
9128
9129 default:
9130 abort();
9131 }
9132 return b0;
9133 }
9134
9135 static struct block *
gen_msg_abbrev(compiler_state_t * cstate,int type)9136 gen_msg_abbrev(compiler_state_t *cstate, int type)
9137 {
9138 struct block *b1;
9139
9140 /*
9141 * Q.2931 signalling protocol messages for handling virtual circuits
9142 * establishment and teardown
9143 */
9144 switch (type) {
9145
9146 case A_SETUP:
9147 b1 = gen_atmfield_code(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
9148 break;
9149
9150 case A_CALLPROCEED:
9151 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
9152 break;
9153
9154 case A_CONNECT:
9155 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
9156 break;
9157
9158 case A_CONNECTACK:
9159 b1 = gen_atmfield_code(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
9160 break;
9161
9162 case A_RELEASE:
9163 b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
9164 break;
9165
9166 case A_RELEASE_DONE:
9167 b1 = gen_atmfield_code(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
9168 break;
9169
9170 default:
9171 abort();
9172 }
9173 return b1;
9174 }
9175
9176 struct block *
gen_atmmulti_abbrev(compiler_state_t * cstate,int type)9177 gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
9178 {
9179 struct block *b0, *b1;
9180
9181 switch (type) {
9182
9183 case A_OAM:
9184 if (!cstate->is_atm)
9185 bpf_error(cstate, "'oam' supported only on raw ATM");
9186 b1 = gen_atmmulti_abbrev(cstate, A_OAMF4);
9187 break;
9188
9189 case A_OAMF4:
9190 if (!cstate->is_atm)
9191 bpf_error(cstate, "'oamf4' supported only on raw ATM");
9192 /* OAM F4 type */
9193 b0 = gen_atmfield_code(cstate, A_VCI, 3, BPF_JEQ, 0);
9194 b1 = gen_atmfield_code(cstate, A_VCI, 4, BPF_JEQ, 0);
9195 gen_or(b0, b1);
9196 b0 = gen_atmfield_code(cstate, A_VPI, 0, BPF_JEQ, 0);
9197 gen_and(b0, b1);
9198 break;
9199
9200 case A_CONNECTMSG:
9201 /*
9202 * Get Q.2931 signalling messages for switched
9203 * virtual connection
9204 */
9205 if (!cstate->is_atm)
9206 bpf_error(cstate, "'connectmsg' supported only on raw ATM");
9207 b0 = gen_msg_abbrev(cstate, A_SETUP);
9208 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9209 gen_or(b0, b1);
9210 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9211 gen_or(b0, b1);
9212 b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
9213 gen_or(b0, b1);
9214 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9215 gen_or(b0, b1);
9216 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9217 gen_or(b0, b1);
9218 b0 = gen_atmtype_abbrev(cstate, A_SC);
9219 gen_and(b0, b1);
9220 break;
9221
9222 case A_METACONNECT:
9223 if (!cstate->is_atm)
9224 bpf_error(cstate, "'metaconnect' supported only on raw ATM");
9225 b0 = gen_msg_abbrev(cstate, A_SETUP);
9226 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9227 gen_or(b0, b1);
9228 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9229 gen_or(b0, b1);
9230 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9231 gen_or(b0, b1);
9232 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9233 gen_or(b0, b1);
9234 b0 = gen_atmtype_abbrev(cstate, A_METAC);
9235 gen_and(b0, b1);
9236 break;
9237
9238 default:
9239 abort();
9240 }
9241 return b1;
9242 }
9243