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 #include <limits.h> /* for INT_MAX */
47
48 #include "pcap-int.h"
49
50 #ifdef HAVE_OS_PROTO_H
51 #include "os-proto.h"
52 #endif
53
54 #include "sf-pcap.h"
55 #include "sf-pcapng.h"
56 #include "pcap-common.h"
57 #include "charconv.h"
58
59 #ifdef _WIN32
60 /*
61 * This isn't exported on Windows, because it would only work if both
62 * WinPcap/Npcap and the code using it were to use the Universal CRT; otherwise,
63 * a FILE structure in WinPcap/Npcap and a FILE structure in the code using it
64 * could be different if they're using different versions of the C runtime.
65 *
66 * Instead, pcap/pcap.h defines it as a macro that wraps the hopen version,
67 * with the wrapper calling _fileno() and _get_osfhandle() themselves,
68 * so that it convert the appropriate CRT version's FILE structure to
69 * a HANDLE (which is OS-defined, not CRT-defined, and is part of the Win32
70 * and Win64 ABIs).
71 */
72 static pcap_t *pcap_fopen_offline_with_tstamp_precision(FILE *, u_int, char *);
73 #endif
74
75 /*
76 * Setting O_BINARY on DOS/Windows is a bit tricky
77 */
78 #if defined(_WIN32)
79 #define SET_BINMODE(f) _setmode(_fileno(f), _O_BINARY)
80 #elif defined(MSDOS)
81 #if defined(__HIGHC__)
82 #define SET_BINMODE(f) setmode(f, O_BINARY)
83 #else
84 #define SET_BINMODE(f) setmode(fileno(f), O_BINARY)
85 #endif
86 #endif
87
88 static int
sf_getnonblock(pcap_t * p _U_)89 sf_getnonblock(pcap_t *p _U_)
90 {
91 /*
92 * This is a savefile, not a live capture file, so never say
93 * it's in non-blocking mode.
94 */
95 return (0);
96 }
97
98 static int
sf_setnonblock(pcap_t * p,int nonblock _U_)99 sf_setnonblock(pcap_t *p, int nonblock _U_)
100 {
101 /*
102 * This is a savefile, not a live capture file, so reject
103 * requests to put it in non-blocking mode. (If it's a
104 * pipe, it could be put in non-blocking mode, but that
105 * would significantly complicate the code to read packets,
106 * as it would have to handle reading partial packets and
107 * keeping the state of the read.)
108 */
109 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
110 "Savefiles cannot be put into non-blocking mode");
111 return (-1);
112 }
113
114 static int
sf_stats(pcap_t * p,struct pcap_stat * ps _U_)115 sf_stats(pcap_t *p, struct pcap_stat *ps _U_)
116 {
117 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
118 "Statistics aren't available from savefiles");
119 return (-1);
120 }
121
122 #ifdef _WIN32
123 static struct pcap_stat *
sf_stats_ex(pcap_t * p,int * size _U_)124 sf_stats_ex(pcap_t *p, int *size _U_)
125 {
126 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
127 "Statistics aren't available from savefiles");
128 return (NULL);
129 }
130
131 static int
sf_setbuff(pcap_t * p,int dim _U_)132 sf_setbuff(pcap_t *p, int dim _U_)
133 {
134 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
135 "The kernel buffer size cannot be set while reading from a file");
136 return (-1);
137 }
138
139 static int
sf_setmode(pcap_t * p,int mode _U_)140 sf_setmode(pcap_t *p, int mode _U_)
141 {
142 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
143 "impossible to set mode while reading from a file");
144 return (-1);
145 }
146
147 static int
sf_setmintocopy(pcap_t * p,int size _U_)148 sf_setmintocopy(pcap_t *p, int size _U_)
149 {
150 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
151 "The mintocopy parameter cannot be set while reading from a file");
152 return (-1);
153 }
154
155 static HANDLE
sf_getevent(pcap_t * pcap)156 sf_getevent(pcap_t *pcap)
157 {
158 (void)snprintf(pcap->errbuf, sizeof(pcap->errbuf),
159 "The read event cannot be retrieved while reading from a file");
160 return (INVALID_HANDLE_VALUE);
161 }
162
163 static int
sf_oid_get_request(pcap_t * p,bpf_u_int32 oid _U_,void * data _U_,size_t * lenp _U_)164 sf_oid_get_request(pcap_t *p, bpf_u_int32 oid _U_, void *data _U_,
165 size_t *lenp _U_)
166 {
167 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
168 "An OID get request cannot be performed on a file");
169 return (PCAP_ERROR);
170 }
171
172 static int
sf_oid_set_request(pcap_t * p,bpf_u_int32 oid _U_,const void * data _U_,size_t * lenp _U_)173 sf_oid_set_request(pcap_t *p, bpf_u_int32 oid _U_, const void *data _U_,
174 size_t *lenp _U_)
175 {
176 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
177 "An OID set request cannot be performed on a file");
178 return (PCAP_ERROR);
179 }
180
181 static u_int
sf_sendqueue_transmit(pcap_t * p,pcap_send_queue * queue _U_,int sync _U_)182 sf_sendqueue_transmit(pcap_t *p, pcap_send_queue *queue _U_, int sync _U_)
183 {
184 pcap_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
185 PCAP_ERRBUF_SIZE);
186 return (0);
187 }
188
189 static int
sf_setuserbuffer(pcap_t * p,int size _U_)190 sf_setuserbuffer(pcap_t *p, int size _U_)
191 {
192 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
193 "The user buffer cannot be set when reading from a file");
194 return (-1);
195 }
196
197 static int
sf_live_dump(pcap_t * p,char * filename _U_,int maxsize _U_,int maxpacks _U_)198 sf_live_dump(pcap_t *p, char *filename _U_, int maxsize _U_, int maxpacks _U_)
199 {
200 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
201 "Live packet dumping cannot be performed when reading from a file");
202 return (-1);
203 }
204
205 static int
sf_live_dump_ended(pcap_t * p,int sync _U_)206 sf_live_dump_ended(pcap_t *p, int sync _U_)
207 {
208 snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
209 "Live packet dumping cannot be performed on a pcap_open_dead pcap_t");
210 return (-1);
211 }
212
213 static PAirpcapHandle
sf_get_airpcap_handle(pcap_t * pcap _U_)214 sf_get_airpcap_handle(pcap_t *pcap _U_)
215 {
216 return (NULL);
217 }
218 #endif
219
220 static int
sf_inject(pcap_t * p,const void * buf _U_,int size _U_)221 sf_inject(pcap_t *p, const void *buf _U_, int size _U_)
222 {
223 pcap_strlcpy(p->errbuf, "Sending packets isn't supported on savefiles",
224 PCAP_ERRBUF_SIZE);
225 return (-1);
226 }
227
228 /*
229 * Set direction flag: Which packets do we accept on a forwarding
230 * single device? IN, OUT or both?
231 */
232 static int
sf_setdirection(pcap_t * p,pcap_direction_t d _U_)233 sf_setdirection(pcap_t *p, pcap_direction_t d _U_)
234 {
235 snprintf(p->errbuf, sizeof(p->errbuf),
236 "Setting direction is not supported on savefiles");
237 return (-1);
238 }
239
240 void
sf_cleanup(pcap_t * p)241 sf_cleanup(pcap_t *p)
242 {
243 if (p->rfile != stdin)
244 (void)fclose(p->rfile);
245 if (p->buffer != NULL)
246 free(p->buffer);
247 pcap_freecode(&p->fcode);
248 }
249
250 #ifdef _WIN32
251 /*
252 * Wrapper for fopen() and _wfopen().
253 *
254 * If we're in UTF-8 mode, map the pathname from UTF-8 to UTF-16LE and
255 * call _wfopen().
256 *
257 * If we're not, just use fopen(); that'll treat it as being in the
258 * local code page.
259 */
260 FILE *
charset_fopen(const char * path,const char * mode)261 charset_fopen(const char *path, const char *mode)
262 {
263 wchar_t *utf16_path;
264 #define MAX_MODE_LEN 16
265 wchar_t utf16_mode[MAX_MODE_LEN+1];
266 int i;
267 char c;
268 FILE *fp;
269 int save_errno;
270
271 if (pcap_utf_8_mode) {
272 /*
273 * Map from UTF-8 to UTF-16LE.
274 * Fail if there are invalid characters in the input
275 * string, rather than converting them to REPLACEMENT
276 * CHARACTER; the latter is appropriate for strings
277 * to be displayed to the user, but for file names
278 * you just want the attempt to open the file to fail.
279 */
280 utf16_path = cp_to_utf_16le(CP_UTF8, path,
281 MB_ERR_INVALID_CHARS);
282 if (utf16_path == NULL) {
283 /*
284 * Error. Assume errno has been set.
285 *
286 * XXX - what about Windows errors?
287 */
288 return (NULL);
289 }
290
291 /*
292 * Now convert the mode to UTF-16LE as well.
293 * We assume the mode is ASCII, and that
294 * it's short, so that's easy.
295 */
296 for (i = 0; (c = *mode) != '\0'; i++, mode++) {
297 if (c > 0x7F) {
298 /* Not an ASCII character; fail with EINVAL. */
299 free(utf16_path);
300 errno = EINVAL;
301 return (NULL);
302 }
303 if (i >= MAX_MODE_LEN) {
304 /* The mode string is longer than we allow. */
305 free(utf16_path);
306 errno = EINVAL;
307 return (NULL);
308 }
309 utf16_mode[i] = c;
310 }
311 utf16_mode[i] = '\0';
312
313 /*
314 * OK, we have UTF-16LE strings; hand them to
315 * _wfopen().
316 */
317 fp = _wfopen(utf16_path, utf16_mode);
318
319 /*
320 * Make sure freeing the UTF-16LE string doesn't
321 * overwrite the error code we got from _wfopen().
322 */
323 save_errno = errno;
324 free(utf16_path);
325 errno = save_errno;
326
327 return (fp);
328 } else {
329 /*
330 * This takes strings in the local code page as an
331 * argument.
332 */
333 return (fopen(path, mode));
334 }
335 }
336 #endif
337
338 pcap_t *
pcap_open_offline_with_tstamp_precision(const char * fname,u_int precision,char * errbuf)339 pcap_open_offline_with_tstamp_precision(const char *fname, u_int precision,
340 char *errbuf)
341 {
342 FILE *fp;
343 pcap_t *p;
344
345 if (fname == NULL) {
346 snprintf(errbuf, PCAP_ERRBUF_SIZE,
347 "A null pointer was supplied as the file name");
348 return (NULL);
349 }
350 if (fname[0] == '-' && fname[1] == '\0')
351 {
352 fp = stdin;
353 if (stdin == NULL) {
354 snprintf(errbuf, PCAP_ERRBUF_SIZE,
355 "The standard input is not open");
356 return (NULL);
357 }
358 #if defined(_WIN32) || defined(MSDOS)
359 /*
360 * We're reading from the standard input, so put it in binary
361 * mode, as savefiles are binary files.
362 */
363 SET_BINMODE(fp);
364 #endif
365 }
366 else {
367 /*
368 * Use charset_fopen(); on Windows, it tests whether we're
369 * in "local code page" or "UTF-8" mode, and treats the
370 * pathname appropriately, and on other platforms, it just
371 * wraps fopen().
372 *
373 * "b" is supported as of C90, so *all* UN*Xes should
374 * support it, even though it does nothing. For MS-DOS,
375 * we again need it.
376 */
377 fp = charset_fopen(fname, "rb");
378 if (fp == NULL) {
379 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
380 errno, "%s", fname);
381 return (NULL);
382 }
383 }
384 p = pcap_fopen_offline_with_tstamp_precision(fp, precision, errbuf);
385 if (p == NULL) {
386 if (fp != stdin)
387 fclose(fp);
388 }
389 return (p);
390 }
391
392 pcap_t *
pcap_open_offline(const char * fname,char * errbuf)393 pcap_open_offline(const char *fname, char *errbuf)
394 {
395 return (pcap_open_offline_with_tstamp_precision(fname,
396 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
397 }
398
399 #ifdef _WIN32
pcap_hopen_offline_with_tstamp_precision(intptr_t osfd,u_int precision,char * errbuf)400 pcap_t* pcap_hopen_offline_with_tstamp_precision(intptr_t osfd, u_int precision,
401 char *errbuf)
402 {
403 int fd;
404 FILE *file;
405
406 fd = _open_osfhandle(osfd, _O_RDONLY);
407 if ( fd < 0 )
408 {
409 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
410 errno, "_open_osfhandle");
411 return NULL;
412 }
413
414 file = _fdopen(fd, "rb");
415 if ( file == NULL )
416 {
417 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
418 errno, "_fdopen");
419 _close(fd);
420 return NULL;
421 }
422
423 return pcap_fopen_offline_with_tstamp_precision(file, precision,
424 errbuf);
425 }
426
pcap_hopen_offline(intptr_t osfd,char * errbuf)427 pcap_t* pcap_hopen_offline(intptr_t osfd, char *errbuf)
428 {
429 return pcap_hopen_offline_with_tstamp_precision(osfd,
430 PCAP_TSTAMP_PRECISION_MICRO, errbuf);
431 }
432 #endif
433
434 /*
435 * Given a link-layer header type and snapshot length, return a
436 * snapshot length to use when reading the file; it's guaranteed
437 * to be > 0 and <= INT_MAX.
438 *
439 * XXX - the only reason why we limit it to <= INT_MAX is so that
440 * it fits in p->snapshot, and the only reason that p->snapshot is
441 * signed is that pcap_snapshot() returns an int, not an unsigned int.
442 */
443 bpf_u_int32
pcap_adjust_snapshot(bpf_u_int32 linktype,bpf_u_int32 snaplen)444 pcap_adjust_snapshot(bpf_u_int32 linktype, bpf_u_int32 snaplen)
445 {
446 if (snaplen == 0 || snaplen > INT_MAX) {
447 /*
448 * Bogus snapshot length; use the maximum for this
449 * link-layer type as a fallback.
450 *
451 * XXX - we don't clamp snapshot lengths that are
452 * <= INT_MAX but > max_snaplen_for_dlt(linktype),
453 * so a capture file could cause us to allocate
454 * a Really Big Buffer.
455 */
456 snaplen = max_snaplen_for_dlt(linktype);
457 }
458 return snaplen;
459 }
460
461 static pcap_t *(*check_headers[])(const uint8_t *, FILE *, u_int, char *, int *) = {
462 pcap_check_header,
463 pcap_ng_check_header
464 };
465
466 #define N_FILE_TYPES (sizeof check_headers / sizeof check_headers[0])
467
468 #ifdef _WIN32
469 static
470 #endif
471 pcap_t *
pcap_fopen_offline_with_tstamp_precision(FILE * fp,u_int precision,char * errbuf)472 pcap_fopen_offline_with_tstamp_precision(FILE *fp, u_int precision,
473 char *errbuf)
474 {
475 register pcap_t *p;
476 uint8_t magic[4];
477 size_t amt_read;
478 u_int i;
479 int err;
480
481 /*
482 * Fail if we were passed a NULL fp.
483 *
484 * That shouldn't happen if we're opening with a path name, but
485 * it could happen if buggy code is opening with a FILE * and
486 * didn't bother to make sure the FILE * isn't null.
487 */
488 if (fp == NULL) {
489 snprintf(errbuf, PCAP_ERRBUF_SIZE,
490 "Null FILE * pointer provided to savefile open routine");
491 return (NULL);
492 }
493
494 /*
495 * Read the first 4 bytes of the file; the network analyzer dump
496 * file formats we support (pcap and pcapng), and several other
497 * formats we might support in the future (such as snoop, DOS and
498 * Windows Sniffer, and Microsoft Network Monitor) all have magic
499 * numbers that are unique in their first 4 bytes.
500 */
501 amt_read = fread(&magic, 1, sizeof(magic), fp);
502 if (amt_read != sizeof(magic)) {
503 if (ferror(fp)) {
504 pcap_fmt_errmsg_for_errno(errbuf, PCAP_ERRBUF_SIZE,
505 errno, "error reading dump file");
506 } else {
507 snprintf(errbuf, PCAP_ERRBUF_SIZE,
508 "truncated dump file; tried to read %zu file header bytes, only got %zu",
509 sizeof(magic), amt_read);
510 }
511 return (NULL);
512 }
513
514 /*
515 * Try all file types.
516 */
517 for (i = 0; i < N_FILE_TYPES; i++) {
518 p = (*check_headers[i])(magic, fp, precision, errbuf, &err);
519 if (p != NULL) {
520 /* Yup, that's it. */
521 goto found;
522 }
523 if (err) {
524 /*
525 * Error trying to read the header.
526 */
527 return (NULL);
528 }
529 }
530
531 /*
532 * Well, who knows what this mess is....
533 */
534 snprintf(errbuf, PCAP_ERRBUF_SIZE, "unknown file format");
535 return (NULL);
536
537 found:
538 p->rfile = fp;
539
540 /* Padding only needed for live capture fcode */
541 p->fddipad = 0;
542
543 #if !defined(_WIN32) && !defined(MSDOS)
544 /*
545 * You can do "select()" and "poll()" on plain files on most
546 * platforms, and should be able to do so on pipes.
547 *
548 * You can't do "select()" on anything other than sockets in
549 * Windows, so, on Win32 systems, we don't have "selectable_fd".
550 */
551 p->selectable_fd = fileno(fp);
552 #endif
553
554 p->read_op = pcap_offline_read;
555 p->inject_op = sf_inject;
556 p->setfilter_op = install_bpf_program;
557 p->setdirection_op = sf_setdirection;
558 p->set_datalink_op = NULL; /* we don't support munging link-layer headers */
559 p->getnonblock_op = sf_getnonblock;
560 p->setnonblock_op = sf_setnonblock;
561 p->stats_op = sf_stats;
562 #ifdef _WIN32
563 p->stats_ex_op = sf_stats_ex;
564 p->setbuff_op = sf_setbuff;
565 p->setmode_op = sf_setmode;
566 p->setmintocopy_op = sf_setmintocopy;
567 p->getevent_op = sf_getevent;
568 p->oid_get_request_op = sf_oid_get_request;
569 p->oid_set_request_op = sf_oid_set_request;
570 p->sendqueue_transmit_op = sf_sendqueue_transmit;
571 p->setuserbuffer_op = sf_setuserbuffer;
572 p->live_dump_op = sf_live_dump;
573 p->live_dump_ended_op = sf_live_dump_ended;
574 p->get_airpcap_handle_op = sf_get_airpcap_handle;
575 #endif
576
577 /*
578 * For offline captures, the standard one-shot callback can
579 * be used for pcap_next()/pcap_next_ex().
580 */
581 p->oneshot_callback = pcap_oneshot;
582
583 /*
584 * Default breakloop operation.
585 */
586 p->breakloop_op = pcap_breakloop_common;
587
588 /*
589 * Savefiles never require special BPF code generation.
590 */
591 p->bpf_codegen_flags = 0;
592
593 p->activated = 1;
594
595 return (p);
596 }
597
598 /*
599 * This isn't needed on Windows; we #define pcap_fopen_offline() as
600 * a wrapper around pcap_hopen_offline(), and we don't call it from
601 * inside this file, so it's unused.
602 */
603 #ifndef _WIN32
604 pcap_t *
pcap_fopen_offline(FILE * fp,char * errbuf)605 pcap_fopen_offline(FILE *fp, char *errbuf)
606 {
607 return (pcap_fopen_offline_with_tstamp_precision(fp,
608 PCAP_TSTAMP_PRECISION_MICRO, errbuf));
609 }
610 #endif
611
612 /*
613 * Read packets from a capture file, and call the callback for each
614 * packet.
615 * If cnt > 0, return after 'cnt' packets, otherwise continue until eof.
616 */
617 int
pcap_offline_read(pcap_t * p,int cnt,pcap_handler callback,u_char * user)618 pcap_offline_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
619 {
620 struct bpf_insn *fcode;
621 int status = 0;
622 int n = 0;
623 u_char *data;
624
625 while (status == 0) {
626 struct pcap_pkthdr h;
627
628 /*
629 * Has "pcap_breakloop()" been called?
630 * If so, return immediately - if we haven't read any
631 * packets, clear the flag and return -2 to indicate
632 * that we were told to break out of the loop, otherwise
633 * leave the flag set, so that the *next* call will break
634 * out of the loop without having read any packets, and
635 * return the number of packets we've processed so far.
636 */
637 if (p->break_loop) {
638 if (n == 0) {
639 p->break_loop = 0;
640 return (-2);
641 } else
642 return (n);
643 }
644
645 status = p->next_packet_op(p, &h, &data);
646 if (status) {
647 if (status == 1)
648 return (0);
649 return (status);
650 }
651
652 if ((fcode = p->fcode.bf_insns) == NULL ||
653 pcap_filter(fcode, data, h.len, h.caplen)) {
654 (*callback)(user, &h, data);
655 if (++n >= cnt && cnt > 0)
656 break;
657 }
658 }
659 /*XXX this breaks semantics tcpslice expects */
660 return (n);
661 }
662