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1 /*
2  * Copyright (c) 1993, 1994, 1995, 1996, 1997
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: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  * savefile.c - supports offline use of tcpdump
22  *	Extraction/creation by Jeffrey Mogul, DECWRL
23  *	Modified by Steve McCanne, LBL.
24  *
25  * Used to save the received packet headers, after filtering, to
26  * a file, and then read them later.
27  * The first record in the file contains saved values for the machine
28  * dependent values so we can print the dump file on any architecture.
29  */
30 
31 #ifdef HAVE_CONFIG_H
32 #include <config.h>
33 #endif
34 
35 #include <pcap-types.h>
36 #ifdef _WIN32
37 #include <io.h>
38 #include <fcntl.h>
39 #endif /* _WIN32 */
40 
41 #include <errno.h>
42 #include <memory.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 
47 #include "pcap-int.h"
48 
49 #ifdef HAVE_OS_PROTO_H
50 #include "os-proto.h"
51 #endif
52 
53 #include "sf-pcap.h"
54 #include "sf-pcapng.h"
55 
56 #ifdef _WIN32
57 /*
58  * These aren't exported on Windows, because they would only work if both
59  * WinPcap and the code using it were to use the Universal CRT; otherwise,
60  * a FILE structure in WinPcap and a FILE structure in the code using it
61  * could be different if they're using different versions of the C runtime.
62  *
63  * Instead, pcap/pcap.h defines them as macros that wrap the hopen versions,
64  * with the wrappers calling _fileno() and _get_osfhandle() themselves,
65  * so that they convert the appropriate CRT version's FILE structure to
66  * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32
67  * and Win64 ABIs).
68  */
69 static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *);
70 static pcap_t *pcap_fopen_offline(FILE *, char *);
71 #endif
72 
73 /*
74  * Setting O_BINARY on DOS/Windows is a bit tricky
75  */
76 #if defined(_WIN32)
77   #define SET_BINMODE(f)  _setmode(_fileno(f), _O_BINARY)
78 #elif defined(MSDOS)
79   #if defined(__HIGHC__)
80   #define SET_BINMODE(f)  setmode(f, O_BINARY)
81   #else
82   #define SET_BINMODE(f)  setmode(fileno(f), O_BINARY)
83   #endif
84 #endif
85 
86 static int
sf_getnonblock(pcap_t * p _U_)87 sf_getnonblock(pcap_t *p _U_)
88 {
89 	/*
90 	 * This is a savefile, not a live capture file, so never say
91 	 * it's in non-blocking mode.
92 	 */
93 	return (0);
94 }
95 
96 static int
sf_setnonblock(pcap_t * p,int nonblock _U_)97 sf_setnonblock(pcap_t *p, int nonblock _U_)
98 {
99 	/*
100 	 * This is a savefile, not a live capture file, so reject
101 	 * requests to put it in non-blocking mode.  (If it's a
102 	 * pipe, it could be put in non-blocking mode, but that
103 	 * would significantly complicate the code to read packets,
104 	 * as it would have to handle reading partial packets and
105 	 * keeping the state of the read.)
106 	 */
107 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
108 	    "Savefiles cannot be put into non-blocking mode");
109 	return (-1);
110 }
111 
112 static int
sf_stats(pcap_t * p,struct pcap_stat * ps _U_)113 sf_stats(pcap_t *p, struct pcap_stat *ps _U_)
114 {
115 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
116 	    "Statistics aren't available from savefiles");
117 	return (-1);
118 }
119 
120 #ifdef _WIN32
121 static struct pcap_stat *
sf_stats_ex(pcap_t * p,int * size)122 sf_stats_ex(pcap_t *p, int *size)
123 {
124 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
125 	    "Statistics aren't available from savefiles");
126 	return (NULL);
127 }
128 
129 static int
sf_setbuff(pcap_t * p,int dim)130 sf_setbuff(pcap_t *p, int dim)
131 {
132 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
133 	    "The kernel buffer size cannot be set while reading from a file");
134 	return (-1);
135 }
136 
137 static int
sf_setmode(pcap_t * p,int mode)138 sf_setmode(pcap_t *p, int mode)
139 {
140 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
141 	    "impossible to set mode while reading from a file");
142 	return (-1);
143 }
144 
145 static int
sf_setmintocopy(pcap_t * p,int size)146 sf_setmintocopy(pcap_t *p, int size)
147 {
148 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
149 	    "The mintocopy parameter cannot be set while reading from a file");
150 	return (-1);
151 }
152 
153 static HANDLE
sf_getevent(pcap_t * pcap)154 sf_getevent(pcap_t *pcap)
155 {
156 	(void)pcap_snprintf(pcap->errbuf, sizeof(pcap->errbuf),
157 	    "The read event cannot be retrieved while reading from a file");
158 	return (INVALID_HANDLE_VALUE);
159 }
160 
161 static int
sf_oid_get_request(pcap_t * p,bpf_u_int32 oid _U_,void * data _U_,size_t * lenp _U_)162 sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,
163     size_t *lenp _U_)
164 {
165 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
166 	    "An OID get request cannot be performed on a file");
167 	return (PCAP_ERROR);
168 }
169 
170 static int
sf_oid_set_request(pcap_t * p,bpf_u_int32 oid _U_,const void * data _U_,size_t * lenp _U_)171 sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,
172     size_t *lenp _U_)
173 {
174 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
175 	    "An OID set request cannot be performed on a file");
176 	return (PCAP_ERROR);
177 }
178 
179 static u_int
sf_sendqueue_transmit(pcap_t * p,pcap_send_queue * queue,int sync)180 sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue, int sync)
181 {
182 	strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
183 	    PCAP_ERRBUF_SIZE);
184 	return (0);
185 }
186 
187 static int
sf_setuserbuffer(pcap_t * p,int size)188 sf_setuserbuffer(pcap_t *p, int size)
189 {
190 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
191 	    "The user buffer cannot be set when reading from a file");
192 	return (-1);
193 }
194 
195 static int
sf_live_dump(pcap_t * p,char * filename,int maxsize,int maxpacks)196 sf_live_dump(pcap_t *p, char *filename, int maxsize, int maxpacks)
197 {
198 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
199 	    "Live packet dumping cannot be performed when reading from a file");
200 	return (-1);
201 }
202 
203 static int
sf_live_dump_ended(pcap_t * p,int sync)204 sf_live_dump_ended(pcap_t *p, int sync)
205 {
206 	pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
207 	    "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
208 	return (-1);
209 }
210 
211 static PAirpcapHandle
sf_get_airpcap_handle(pcap_t * pcap)212 sf_get_airpcap_handle(pcap_t *pcap)
213 {
214 	return (NULL);
215 }
216 #endif
217 
218 static int
sf_inject(pcap_t * p,const void * buf _U_,size_t size _U_)219 sf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
220 {
221 	strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
222 	    PCAP_ERRBUF_SIZE);
223 	return (-1);
224 }
225 
226 /*
227  * Set direction flag: Which packets do we accept on a forwarding
228  * single device? IN, OUT or both?
229  */
230 static int
sf_setdirection(pcap_t * p,pcap_direction_t d _U_)231 sf_setdirection(pcap_t *p, pcap_direction_t d _U_)
232 {
233 	pcap_snprintf(p->errbuf, sizeof(p->errbuf),
234 	    "Setting direction is not supported on savefiles");
235 	return (-1);
236 }
237 
238 void
sf_cleanup(pcap_t * p)239 sf_cleanup(pcap_t *p)
240 {
241 	if (p->rfile != stdin)
242 		(void)fclose(p->rfile);
243 	if (p->buffer != NULL)
244 		free(p->buffer);
245 	pcap_freecode(&p->fcode);
246 }
247 
248 pcap_t *
pcap_open_offline_with_tstamp_precision(const char * fname,u_int precision,char * errbuf)249 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
250 					char *errbuf)
251 {
252 	FILE *fp;
253 	pcap_t *p;
254 
255 	if (fname == NULL) {
256 		pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
257 		    "A null pointer was supplied as the file name");
258 		return (NULL);
259 	}
260 	if (fname[0] == '-' && fname[1] == '\0')
261 	{
262 		fp = stdin;
263 #if defined(_WIN32) || defined(MSDOS)
264 		/*
265 		 * We're reading from the standard input, so put it in binary
266 		 * mode, as savefiles are binary files.
267 		 */
268 		SET_BINMODE(fp);
269 #endif
270 	}
271 	else {
272 		/*
273 		 * "b" is supported as of C90, so *all* UN*Xes should
274 		 * support it, even though it does nothing.  It's
275 		 * required on Windows, as the file is a binary file
276 		 * and must be read in binary mode.
277 		 */
278 		fp = fopen(fname, "rb");
279 		if (fp == NULL) {
280 			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
281 			    errno, "%s", fname);
282 			return (NULL);
283 		}
284 	}
285 	p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
286 	if (p == NULL) {
287 		if (fp != stdin)
288 			fclose(fp);
289 	}
290 	return (p);
291 }
292 
293 pcap_t *
pcap_open_offline(const char * fname,char * errbuf)294 pcap_open_offline(const char *fname, char *errbuf)
295 {
296 	return (pcap_open_offline_with_tstamp_precision(fname,
297 	    PCAP_TSTAMP_PRECISION_MICRO, errbuf));
298 }
299 
300 #ifdef _WIN32
pcap_hopen_offline_with_tstamp_precision(intptr_t osfd,u_int precision,char * errbuf)301 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
302     char *errbuf)
303 {
304 	int fd;
305 	FILE *file;
306 
307 	fd = _open_osfhandle(osfd, _O_RDONLY);
308 	if ( fd < 0 )
309 	{
310 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
311 		    errno, "_open_osfhandle");
312 		return NULL;
313 	}
314 
315 	file = _fdopen(fd, "rb");
316 	if ( file == NULL )
317 	{
318 		pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
319 		    errno, "_fdopen");
320 		return NULL;
321 	}
322 
323 	return pcap_fopen_offline_with_tstamp_precision(file, precision,
324 	    errbuf);
325 }
326 
pcap_hopen_offline(intptr_t osfd,char * errbuf)327 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
328 {
329 	return pcap_hopen_offline_with_tstamp_precision(osfd,
330 	    PCAP_TSTAMP_PRECISION_MICRO, errbuf);
331 }
332 #endif
333 
334 static pcap_t *(*check_headers[])(bpf_u_int32, FILE *, u_int, char *, int *) = {
335 	pcap_check_header,
336 	pcap_ng_check_header
337 };
338 
339 #define	N_FILE_TYPES	(sizeof check_headers / sizeof check_headers[0])
340 
341 #ifdef _WIN32
342 static
343 #endif
344 pcap_t *
pcap_fopen_offline_with_tstamp_precision(FILE * fp,u_int precision,char * errbuf)345 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
346     char *errbuf)
347 {
348 	register pcap_t *p;
349 	bpf_u_int32 magic;
350 	size_t amt_read;
351 	u_int i;
352 	int err;
353 
354 	/*
355 	 * Read the first 4 bytes of the file; the network analyzer dump
356 	 * file formats we support (pcap and pcapng), and several other
357 	 * formats we might support in the future (such as snoop, DOS and
358 	 * Windows Sniffer, and Microsoft Network Monitor) all have magic
359 	 * numbers that are unique in their first 4 bytes.
360 	 */
361 	amt_read = fread((char *)&magic, 1, sizeof(magic), fp);
362 	if (amt_read != sizeof(magic)) {
363 		if (ferror(fp)) {
364 			pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
365 			    errno, "error reading dump file");
366 		} else {
367 			pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE,
368 			    "truncated dump file; tried to read %lu file header bytes, only got %lu",
369 			    (unsigned long)sizeof(magic),
370 			    (unsigned long)amt_read);
371 		}
372 		return (NULL);
373 	}
374 
375 	/*
376 	 * Try all file types.
377 	 */
378 	for (i = 0; i < N_FILE_TYPES; i++) {
379 		p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
380 		if (p != NULL) {
381 			/* Yup, that's it. */
382 			goto found;
383 		}
384 		if (err) {
385 			/*
386 			 * Error trying to read the header.
387 			 */
388 			return (NULL);
389 		}
390 	}
391 
392 	/*
393 	 * Well, who knows what this mess is....
394 	 */
395 	pcap_snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
396 	return (NULL);
397 
398 found:
399 	p->rfile = fp;
400 
401 	/* Padding only needed for live capture fcode */
402 	p->fddipad = 0;
403 
404 #if !defined(_WIN32) && !defined(MSDOS)
405 	/*
406 	 * You can do "select()" and "poll()" on plain files on most
407 	 * platforms, and should be able to do so on pipes.
408 	 *
409 	 * You can't do "select()" on anything other than sockets in
410 	 * Windows, so, on Win32 systems, we don't have "selectable_fd".
411 	 */
412 	p->selectable_fd = fileno(fp);
413 #endif
414 
415 	p->read_op = pcap_offline_read;
416 	p->inject_op = sf_inject;
417 	p->setfilter_op = install_bpf_program;
418 	p->setdirection_op = sf_setdirection;
419 	p->set_datalink_op = NULL;	/* we don't support munging link-layer headers */
420 	p->getnonblock_op = sf_getnonblock;
421 	p->setnonblock_op = sf_setnonblock;
422 	p->stats_op = sf_stats;
423 #ifdef _WIN32
424 	p->stats_ex_op = sf_stats_ex;
425 	p->setbuff_op = sf_setbuff;
426 	p->setmode_op = sf_setmode;
427 	p->setmintocopy_op = sf_setmintocopy;
428 	p->getevent_op = sf_getevent;
429 	p->oid_get_request_op = sf_oid_get_request;
430 	p->oid_set_request_op = sf_oid_set_request;
431 	p->sendqueue_transmit_op = sf_sendqueue_transmit;
432 	p->setuserbuffer_op = sf_setuserbuffer;
433 	p->live_dump_op = sf_live_dump;
434 	p->live_dump_ended_op = sf_live_dump_ended;
435 	p->get_airpcap_handle_op = sf_get_airpcap_handle;
436 #endif
437 
438 	/*
439 	 * For offline captures, the standard one-shot callback can
440 	 * be used for pcap_next()/pcap_next_ex().
441 	 */
442 	p->oneshot_callback = pcap_oneshot;
443 
444 	/*
445 	 * Savefiles never require special BPF code generation.
446 	 */
447 	p->bpf_codegen_flags = 0;
448 
449 	p->activated = 1;
450 
451 	return (p);
452 }
453 
454 #ifdef _WIN32
455 static
456 #endif
457 pcap_t *
pcap_fopen_offline(FILE * fp,char * errbuf)458 pcap_fopen_offline(FILE *fp, char *errbuf)
459 {
460 	return (pcap_fopen_offline_with_tstamp_precision(fp,
461 	    PCAP_TSTAMP_PRECISION_MICRO, errbuf));
462 }
463 
464 /*
465  * Read packets from a capture file, and call the callback for each
466  * packet.
467  * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
468  */
469 int
pcap_offline_read(pcap_t * p,int cnt,pcap_handler callback,u_char * user)470 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
471 {
472 	struct bpf_insn *fcode;
473 	int status = 0;
474 	int n = 0;
475 	u_char *data;
476 
477 	while (status == 0) {
478 		struct pcap_pkthdr h;
479 
480 		/*
481 		 * Has "pcap_breakloop()" been called?
482 		 * If so, return immediately - if we haven't read any
483 		 * packets, clear the flag and return -2 to indicate
484 		 * that we were told to break out of the loop, otherwise
485 		 * leave the flag set, so that the *next* call will break
486 		 * out of the loop without having read any packets, and
487 		 * return the number of packets we've processed so far.
488 		 */
489 		if (p->break_loop) {
490 			if (n == 0) {
491 				p->break_loop = 0;
492 				return (-2);
493 			} else
494 				return (n);
495 		}
496 
497 		status = p->next_packet_op(p, &h, &data);
498 		if (status) {
499 			if (status == 1)
500 				return (0);
501 			return (status);
502 		}
503 
504 		if ((fcode = p->fcode.bf_insns) == NULL ||
505 		    bpf_filter(fcode, data, h.len, h.caplen)) {
506 			(*callback)(user, &h, data);
507 			if (++n >= cnt && cnt > 0)
508 				break;
509 		}
510 	}
511 	/*XXX this breaks semantics tcpslice expects */
512 	return (n);
513 }
514