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1 /*
2  * Copyright (c) 1994, 1995, 1996
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the Computer Systems
16  *	Engineering Group at Lawrence Berkeley Laboratory.
17  * 4. Neither the name of the University nor of the Laboratory may be used
18  *    to endorse or promote products derived from this software without
19  *    specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #ifndef pcap_int_h
35 #define	pcap_int_h
36 
37 #include <signal.h>
38 
39 #include <pcap/pcap.h>
40 
41 #include "varattrs.h"
42 #include "fmtutils.h"
43 
44 /*
45  * Version string.
46  * Uses PACKAGE_VERSION from config.h.
47  */
48 #define PCAP_VERSION_STRING "libpcap version " PACKAGE_VERSION
49 
50 #ifdef __cplusplus
51 extern "C" {
52 #endif
53 
54 #ifdef MSDOS
55   #include <fcntl.h>
56   #include <io.h>
57 #endif
58 
59 /*
60  * Swap byte ordering of unsigned long long timestamp on a big endian
61  * machine.
62  */
63 #define SWAPLL(ull)  ((ull & 0xff00000000000000ULL) >> 56) | \
64                       ((ull & 0x00ff000000000000ULL) >> 40) | \
65                       ((ull & 0x0000ff0000000000ULL) >> 24) | \
66                       ((ull & 0x000000ff00000000ULL) >> 8)  | \
67                       ((ull & 0x00000000ff000000ULL) << 8)  | \
68                       ((ull & 0x0000000000ff0000ULL) << 24) | \
69                       ((ull & 0x000000000000ff00ULL) << 40) | \
70                       ((ull & 0x00000000000000ffULL) << 56)
71 
72 /*
73  * Maximum snapshot length.
74  *
75  * Somewhat arbitrary, but chosen to be:
76  *
77  *    1) big enough for maximum-size Linux loopback packets (65549)
78  *       and some USB packets captured with USBPcap:
79  *
80  *           http://desowin.org/usbpcap/
81  *
82  *       (> 131072, < 262144)
83  *
84  * and
85  *
86  *    2) small enough not to cause attempts to allocate huge amounts of
87  *       memory; some applications might use the snapshot length in a
88  *       savefile header to control the size of the buffer they allocate,
89  *       so a size of, say, 2^31-1 might not work well.
90  *
91  * We don't enforce this in pcap_set_snaplen(), but we use it internally.
92  */
93 #define MAXIMUM_SNAPLEN		262144
94 
95 struct pcap_opt {
96 	char	*device;
97 	int	timeout;	/* timeout for buffering */
98 	u_int	buffer_size;
99 	int	promisc;
100 	int	rfmon;		/* monitor mode */
101 	int	immediate;	/* immediate mode - deliver packets as soon as they arrive */
102 	int	nonblock;	/* non-blocking mode - don't wait for packets to be delivered, return "no packets available" */
103 	int	tstamp_type;
104 	int	tstamp_precision;
105 
106 	/*
107 	 * Platform-dependent options.
108 	 */
109 #ifdef __linux__
110 	int	protocol;	/* protocol to use when creating PF_PACKET socket */
111 #endif
112 #ifdef _WIN32
113 	int	nocapture_local;/* disable NPF loopback */
114 #endif
115 };
116 
117 typedef int	(*activate_op_t)(pcap_t *);
118 typedef int	(*can_set_rfmon_op_t)(pcap_t *);
119 typedef int	(*read_op_t)(pcap_t *, int cnt, pcap_handler, u_char *);
120 typedef int	(*next_packet_op_t)(pcap_t *, struct pcap_pkthdr *, u_char **);
121 typedef int	(*inject_op_t)(pcap_t *, const void *, size_t);
122 typedef void	(*save_current_filter_op_t)(pcap_t *, const char *);
123 typedef int	(*setfilter_op_t)(pcap_t *, struct bpf_program *);
124 typedef int	(*setdirection_op_t)(pcap_t *, pcap_direction_t);
125 typedef int	(*set_datalink_op_t)(pcap_t *, int);
126 typedef int	(*getnonblock_op_t)(pcap_t *);
127 typedef int	(*setnonblock_op_t)(pcap_t *, int);
128 typedef int	(*stats_op_t)(pcap_t *, struct pcap_stat *);
129 #ifdef _WIN32
130 typedef struct pcap_stat *(*stats_ex_op_t)(pcap_t *, int *);
131 typedef int	(*setbuff_op_t)(pcap_t *, int);
132 typedef int	(*setmode_op_t)(pcap_t *, int);
133 typedef int	(*setmintocopy_op_t)(pcap_t *, int);
134 typedef HANDLE	(*getevent_op_t)(pcap_t *);
135 typedef int	(*oid_get_request_op_t)(pcap_t *, bpf_u_int32, void *, size_t *);
136 typedef int	(*oid_set_request_op_t)(pcap_t *, bpf_u_int32, const void *, size_t *);
137 typedef u_int	(*sendqueue_transmit_op_t)(pcap_t *, pcap_send_queue *, int);
138 typedef int	(*setuserbuffer_op_t)(pcap_t *, int);
139 typedef int	(*live_dump_op_t)(pcap_t *, char *, int, int);
140 typedef int	(*live_dump_ended_op_t)(pcap_t *, int);
141 typedef PAirpcapHandle	(*get_airpcap_handle_op_t)(pcap_t *);
142 #endif
143 typedef void	(*cleanup_op_t)(pcap_t *);
144 
145 /*
146  * We put all the stuff used in the read code path at the beginning,
147  * to try to keep it together in the same cache line or lines.
148  */
149 struct pcap {
150 	/*
151 	 * Method to call to read packets on a live capture.
152 	 */
153 	read_op_t read_op;
154 
155 	/*
156 	 * Method to call to read the next packet from a savefile.
157 	 */
158 	next_packet_op_t next_packet_op;
159 
160 #ifdef _WIN32
161 	HANDLE handle;
162 #else
163 	int fd;
164 #endif /* _WIN32 */
165 
166 	/*
167 	 * Read buffer.
168 	 */
169 	u_int bufsize;
170 	void *buffer;
171 	u_char *bp;
172 	int cc;
173 
174 	sig_atomic_t break_loop; /* flag set to force break from packet-reading loop */
175 
176 	void *priv;		/* private data for methods */
177 
178 #ifdef ENABLE_REMOTE
179 	struct pcap_samp rmt_samp;	/* parameters related to the sampling process. */
180 #endif
181 
182 	int swapped;
183 	FILE *rfile;		/* null if live capture, non-null if savefile */
184 	u_int fddipad;
185 	struct pcap *next;	/* list of open pcaps that need stuff cleared on close */
186 
187 	/*
188 	 * File version number; meaningful only for a savefile, but we
189 	 * keep it here so that apps that (mistakenly) ask for the
190 	 * version numbers will get the same zero values that they
191 	 * always did.
192 	 */
193 	int version_major;
194 	int version_minor;
195 
196 	int snapshot;
197 	int linktype;		/* Network linktype */
198 	int linktype_ext;       /* Extended information stored in the linktype field of a file */
199 	int tzoff;		/* timezone offset */
200 	int offset;		/* offset for proper alignment */
201 	int activated;		/* true if the capture is really started */
202 	int oldstyle;		/* if we're opening with pcap_open_live() */
203 
204 	struct pcap_opt opt;
205 
206 	/*
207 	 * Place holder for pcap_next().
208 	 */
209 	u_char *pkt;
210 
211 #ifdef _WIN32
212 	struct pcap_stat stat;	/* used for pcap_stats_ex() */
213 #endif
214 
215 	/* We're accepting only packets in this direction/these directions. */
216 	pcap_direction_t direction;
217 
218 	/*
219 	 * Flags to affect BPF code generation.
220 	 */
221 	int bpf_codegen_flags;
222 
223 #if !defined(_WIN32) && !defined(MSDOS)
224 	int selectable_fd;	/* FD on which select()/poll()/epoll_wait()/kevent()/etc. can be done */
225 
226 	/*
227 	 * In case there either is no selectable FD, or there is but
228 	 * it doesn't necessarily work (e.g., if it doesn't get notified
229 	 * if the packet capture timeout expires before the buffer
230 	 * fills up), this points to a timeout that should be used
231 	 * in select()/poll()/epoll_wait()/kevent() call.  The pcap_t should
232 	 * be put into non-blocking mode, and, if the timeout expires on
233 	 * the call, an attempt should be made to read packets from all
234 	 * pcap_t's with a required timeout, and the code must be
235 	 * prepared not to see any packets from the attempt.
236 	 */
237 	struct timeval *required_select_timeout;
238 #endif
239 
240 	/*
241 	 * Placeholder for filter code if bpf not in kernel.
242 	 */
243 	struct bpf_program fcode;
244 
245 	char errbuf[PCAP_ERRBUF_SIZE + 1];
246 	int dlt_count;
247 	u_int *dlt_list;
248 	int tstamp_type_count;
249 	u_int *tstamp_type_list;
250 	int tstamp_precision_count;
251 	u_int *tstamp_precision_list;
252 
253 	struct pcap_pkthdr pcap_header;	/* This is needed for the pcap_next_ex() to work */
254 
255 	/*
256 	 * More methods.
257 	 */
258 	activate_op_t activate_op;
259 	can_set_rfmon_op_t can_set_rfmon_op;
260 	inject_op_t inject_op;
261 	save_current_filter_op_t save_current_filter_op;
262 	setfilter_op_t setfilter_op;
263 	setdirection_op_t setdirection_op;
264 	set_datalink_op_t set_datalink_op;
265 	getnonblock_op_t getnonblock_op;
266 	setnonblock_op_t setnonblock_op;
267 	stats_op_t stats_op;
268 
269 	/*
270 	 * Routine to use as callback for pcap_next()/pcap_next_ex().
271 	 */
272 	pcap_handler oneshot_callback;
273 
274 #ifdef _WIN32
275 	/*
276 	 * These are, at least currently, specific to the Win32 NPF
277 	 * driver.
278 	 */
279 	stats_ex_op_t stats_ex_op;
280 	setbuff_op_t setbuff_op;
281 	setmode_op_t setmode_op;
282 	setmintocopy_op_t setmintocopy_op;
283 	getevent_op_t getevent_op;
284 	oid_get_request_op_t oid_get_request_op;
285 	oid_set_request_op_t oid_set_request_op;
286 	sendqueue_transmit_op_t sendqueue_transmit_op;
287 	setuserbuffer_op_t setuserbuffer_op;
288 	live_dump_op_t live_dump_op;
289 	live_dump_ended_op_t live_dump_ended_op;
290 	get_airpcap_handle_op_t get_airpcap_handle_op;
291 #endif
292 	cleanup_op_t cleanup_op;
293 };
294 
295 /*
296  * BPF code generation flags.
297  */
298 #define BPF_SPECIAL_VLAN_HANDLING	0x00000001	/* special VLAN handling for Linux */
299 
300 /*
301  * This is a timeval as stored in a savefile.
302  * It has to use the same types everywhere, independent of the actual
303  * `struct timeval'; `struct timeval' has 32-bit tv_sec values on some
304  * platforms and 64-bit tv_sec values on other platforms, and writing
305  * out native `struct timeval' values would mean files could only be
306  * read on systems with the same tv_sec size as the system on which
307  * the file was written.
308  */
309 
310 struct pcap_timeval {
311     bpf_int32 tv_sec;		/* seconds */
312     bpf_int32 tv_usec;		/* microseconds */
313 };
314 
315 /*
316  * This is a `pcap_pkthdr' as actually stored in a savefile.
317  *
318  * Do not change the format of this structure, in any way (this includes
319  * changes that only affect the length of fields in this structure),
320  * and do not make the time stamp anything other than seconds and
321  * microseconds (e.g., seconds and nanoseconds).  Instead:
322  *
323  *	introduce a new structure for the new format;
324  *
325  *	send mail to "tcpdump-workers@lists.tcpdump.org", requesting
326  *	a new magic number for your new capture file format, and, when
327  *	you get the new magic number, put it in "savefile.c";
328  *
329  *	use that magic number for save files with the changed record
330  *	header;
331  *
332  *	make the code in "savefile.c" capable of reading files with
333  *	the old record header as well as files with the new record header
334  *	(using the magic number to determine the header format).
335  *
336  * Then supply the changes by forking the branch at
337  *
338  *	https://github.com/the-tcpdump-group/libpcap/issues
339  *
340  * and issuing a pull request, so that future versions of libpcap and
341  * programs that use it (such as tcpdump) will be able to read your new
342  * capture file format.
343  */
344 
345 struct pcap_sf_pkthdr {
346     struct pcap_timeval ts;	/* time stamp */
347     bpf_u_int32 caplen;		/* length of portion present */
348     bpf_u_int32 len;		/* length this packet (off wire) */
349 };
350 
351 /*
352  * How a `pcap_pkthdr' is actually stored in savefiles written
353  * by some patched versions of libpcap (e.g. the ones in Red
354  * Hat Linux 6.1 and 6.2).
355  *
356  * Do not change the format of this structure, in any way (this includes
357  * changes that only affect the length of fields in this structure).
358  * Instead, introduce a new structure, as per the above.
359  */
360 
361 struct pcap_sf_patched_pkthdr {
362     struct pcap_timeval ts;	/* time stamp */
363     bpf_u_int32 caplen;		/* length of portion present */
364     bpf_u_int32 len;		/* length this packet (off wire) */
365     int		index;
366     unsigned short protocol;
367     unsigned char pkt_type;
368 };
369 
370 /*
371  * User data structure for the one-shot callback used for pcap_next()
372  * and pcap_next_ex().
373  */
374 struct oneshot_userdata {
375 	struct pcap_pkthdr *hdr;
376 	const u_char **pkt;
377 	pcap_t *pd;
378 };
379 
380 #ifndef min
381 #define min(a, b) ((a) > (b) ? (b) : (a))
382 #endif
383 
384 int	pcap_offline_read(pcap_t *, int, pcap_handler, u_char *);
385 
386 #include <stdarg.h>
387 
388 #include "portability.h"
389 
390 /*
391  * Does the packet count argument to a module's read routine say
392  * "supply packets until you run out of packets"?
393  */
394 #define PACKET_COUNT_IS_UNLIMITED(count)	((count) <= 0)
395 
396 /*
397  * Routines that most pcap implementations can use for non-blocking mode.
398  */
399 #if !defined(_WIN32) && !defined(MSDOS)
400 int	pcap_getnonblock_fd(pcap_t *);
401 int	pcap_setnonblock_fd(pcap_t *p, int);
402 #endif
403 
404 /*
405  * Internal interfaces for "pcap_create()".
406  *
407  * "pcap_create_interface()" is the routine to do a pcap_create on
408  * a regular network interface.  There are multiple implementations
409  * of this, one for each platform type (Linux, BPF, DLPI, etc.),
410  * with the one used chosen by the configure script.
411  *
412  * "pcap_create_common()" allocates and fills in a pcap_t, for use
413  * by pcap_create routines.
414  */
415 pcap_t	*pcap_create_interface(const char *, char *);
416 pcap_t	*pcap_create_common(char *, size_t);
417 int	pcap_do_addexit(pcap_t *);
418 void	pcap_add_to_pcaps_to_close(pcap_t *);
419 void	pcap_remove_from_pcaps_to_close(pcap_t *);
420 void	pcap_cleanup_live_common(pcap_t *);
421 int	pcap_check_activated(pcap_t *);
422 
423 /*
424  * Internal interfaces for "pcap_findalldevs()".
425  *
426  * A pcap_if_list_t * is a reference to a list of devices.
427  *
428  * A get_if_flags_func is a platform-dependent function called to get
429  * additional interface flags.
430  *
431  * "pcap_platform_finddevs()" is the platform-dependent routine to
432  * find local network interfaces.
433  *
434  * "pcap_findalldevs_interfaces()" is a helper to find those interfaces
435  * using the "standard" mechanisms (SIOCGIFCONF, "getifaddrs()", etc.).
436  *
437  * "add_dev()" adds an entry to a pcap_if_list_t.
438  *
439  * "find_dev()" tries to find a device, by name, in a pcap_if_list_t.
440  *
441  * "find_or_add_dev()" checks whether a device is already in a pcap_if_list_t
442  * and, if not, adds an entry for it.
443  */
444 struct pcap_if_list;
445 typedef struct pcap_if_list pcap_if_list_t;
446 typedef int (*get_if_flags_func)(const char *, bpf_u_int32 *, char *);
447 int	pcap_platform_finddevs(pcap_if_list_t *, char *);
448 #if !defined(_WIN32) && !defined(MSDOS)
449 int	pcap_findalldevs_interfaces(pcap_if_list_t *, char *,
450 	    int (*)(const char *), get_if_flags_func);
451 #endif
452 pcap_if_t *find_or_add_dev(pcap_if_list_t *, const char *, bpf_u_int32,
453 	    get_if_flags_func, const char *, char *);
454 pcap_if_t *find_dev(pcap_if_list_t *, const char *);
455 pcap_if_t *add_dev(pcap_if_list_t *, const char *, bpf_u_int32, const char *,
456 	    char *);
457 int	add_addr_to_dev(pcap_if_t *, struct sockaddr *, size_t,
458 	    struct sockaddr *, size_t, struct sockaddr *, size_t,
459 	    struct sockaddr *dstaddr, size_t, char *errbuf);
460 #ifndef _WIN32
461 pcap_if_t *find_or_add_if(pcap_if_list_t *, const char *, bpf_u_int32,
462 	    get_if_flags_func, char *);
463 int	add_addr_to_if(pcap_if_list_t *, const char *, bpf_u_int32,
464 	    get_if_flags_func,
465 	    struct sockaddr *, size_t, struct sockaddr *, size_t,
466 	    struct sockaddr *, size_t, struct sockaddr *, size_t, char *);
467 #endif
468 
469 /*
470  * Internal interfaces for "pcap_open_offline()".
471  *
472  * "pcap_open_offline_common()" allocates and fills in a pcap_t, for use
473  * by pcap_open_offline routines.
474  *
475  * "sf_cleanup()" closes the file handle associated with a pcap_t, if
476  * appropriate, and frees all data common to all modules for handling
477  * savefile types.
478  */
479 pcap_t	*pcap_open_offline_common(char *ebuf, size_t size);
480 void	sf_cleanup(pcap_t *p);
481 
482 /*
483  * Internal interfaces for both "pcap_create()" and routines that
484  * open savefiles.
485  *
486  * "pcap_oneshot()" is the standard one-shot callback for "pcap_next()"
487  * and "pcap_next_ex()".
488  */
489 void	pcap_oneshot(u_char *, const struct pcap_pkthdr *, const u_char *);
490 
491 #ifdef _WIN32
492 void	pcap_win32_err_to_str(DWORD, char *);
493 #endif
494 
495 int	install_bpf_program(pcap_t *, struct bpf_program *);
496 
497 int	pcap_strcasecmp(const char *, const char *);
498 
499 #ifdef YYDEBUG
500 extern int pcap_debug;
501 #endif
502 
503 #ifdef __cplusplus
504 }
505 #endif
506 
507 #endif
508