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Add bounds checks.
[tcpdump] / tcpdump.c
1 /*
2 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
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 * Support for splitting captures into multiple files with a maximum
22 * file size:
23 *
24 * Copyright (c) 2001
25 * Seth Webster <swebster@sst.ll.mit.edu>
26 */
27
28 #ifndef lint
29 static const char copyright[] _U_ =
30 "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
31 The Regents of the University of California. All rights reserved.\n";
32 static const char rcsid[] _U_ =
33 "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.216.2.10 2004-03-17 19:47:48 guy Exp $ (LBL)";
34 #endif
35
36 /*
37 * tcpdump - monitor tcp/ip traffic on an ethernet.
38 *
39 * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
40 * Mercilessly hacked and occasionally improved since then via the
41 * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
42 */
43
44 #ifdef HAVE_CONFIG_H
45 #include "config.h"
46 #endif
47
48 #include <tcpdump-stdinc.h>
49
50 #ifdef WIN32
51 #include "getopt.h"
52 #include "w32_fzs.h"
53 extern int strcasecmp (const char *__s1, const char *__s2);
54 extern int SIZE_BUF;
55 #define off_t long
56 #define uint UINT
57 #endif /* WIN32 */
58
59 #include <pcap.h>
60 #include <signal.h>
61 #include <stdio.h>
62 #include <stdlib.h>
63 #include <string.h>
64
65 #include "interface.h"
66 #include "addrtoname.h"
67 #include "machdep.h"
68 #include "setsignal.h"
69 #include "gmt2local.h"
70 #include "pcap-missing.h"
71
72 int dflag; /* print filter code */
73 int eflag; /* print ethernet header */
74 int fflag; /* don't translate "foreign" IP address */
75 int Lflag; /* list available data link types and exit */
76 int nflag; /* leave addresses as numbers */
77 int Nflag; /* remove domains from printed host names */
78 int Oflag = 1; /* run filter code optimizer */
79 int pflag; /* don't go promiscuous */
80 int qflag; /* quick (shorter) output */
81 int Rflag = 1; /* print sequence # field in AH/ESP*/
82 int sflag = 0; /* use the libsmi to translate OIDs */
83 int Sflag; /* print raw TCP sequence numbers */
84 int tflag = 1; /* print packet arrival time */
85 int Uflag = 0; /* "unbuffered" output of dump files */
86 int uflag = 0; /* Print undecoded NFS handles */
87 int vflag; /* verbose */
88 int xflag; /* print packet in hex */
89 int Xflag; /* print packet in ascii as well as hex */
90 off_t Cflag = 0; /* rotate dump files after this many bytes */
91 int Aflag = 0; /* print packet only in ascii observing LF, CR, TAB, SPACE */
92 int dlt = -1; /* if != -1, ask libpcap for the DLT it names */
93
94 const char *dlt_name = NULL;
95
96 char *espsecret = NULL; /* ESP secret key */
97
98 int packettype;
99
100 static int infodelay;
101 static int infoprint;
102
103 char *program_name;
104
105 int32_t thiszone; /* seconds offset from gmt to local time */
106
107 /* Forwards */
108 static RETSIGTYPE cleanup(int);
109 static void usage(void) __attribute__((noreturn));
110 static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
111
112 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
113 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
114 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
115
116 #ifdef SIGINFO
117 RETSIGTYPE requestinfo(int);
118 #endif
119
120 static void info(int);
121 static u_int packets_captured;
122
123 /* Length of saved portion of packet. */
124 int snaplen = DEFAULT_SNAPLEN;
125
126 typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);
127
128 struct printer {
129 if_printer f;
130 int type;
131 };
132
133 static struct printer printers[] = {
134 { arcnet_if_print, DLT_ARCNET },
135 #ifdef DLT_ARCNET_LINUX
136 { arcnet_linux_if_print, DLT_ARCNET_LINUX },
137 #endif
138 { ether_if_print, DLT_EN10MB },
139 { token_if_print, DLT_IEEE802 },
140 #ifdef DLT_LANE8023
141 { lane_if_print, DLT_LANE8023 },
142 #endif
143 #ifdef DLT_CIP
144 { cip_if_print, DLT_CIP },
145 #endif
146 #ifdef DLT_ATM_CLIP
147 { cip_if_print, DLT_ATM_CLIP },
148 #endif
149 { sl_if_print, DLT_SLIP },
150 #ifdef DLT_SLIP_BSDOS
151 { sl_bsdos_if_print, DLT_SLIP_BSDOS },
152 #endif
153 { ppp_if_print, DLT_PPP },
154 #ifdef DLT_PPP_BSDOS
155 { ppp_bsdos_if_print, DLT_PPP_BSDOS },
156 #endif
157 { fddi_if_print, DLT_FDDI },
158 { null_if_print, DLT_NULL },
159 #ifdef DLT_LOOP
160 { null_if_print, DLT_LOOP },
161 #endif
162 { raw_if_print, DLT_RAW },
163 { atm_if_print, DLT_ATM_RFC1483 },
164 #ifdef DLT_C_HDLC
165 { chdlc_if_print, DLT_C_HDLC },
166 #endif
167 #ifdef DLT_HDLC
168 { chdlc_if_print, DLT_HDLC },
169 #endif
170 #ifdef DLT_PPP_SERIAL
171 { ppp_hdlc_if_print, DLT_PPP_SERIAL },
172 #endif
173 #ifdef DLT_PPP_ETHER
174 { pppoe_if_print, DLT_PPP_ETHER },
175 #endif
176 #ifdef DLT_LINUX_SLL
177 { sll_if_print, DLT_LINUX_SLL },
178 #endif
179 #ifdef DLT_IEEE802_11
180 { ieee802_11_if_print, DLT_IEEE802_11},
181 #endif
182 #ifdef DLT_LTALK
183 { ltalk_if_print, DLT_LTALK },
184 #endif
185 #ifdef DLT_PFLOG
186 { pflog_if_print, DLT_PFLOG },
187 #endif
188 #ifdef DLT_FR
189 { fr_if_print, DLT_FR },
190 #endif
191 #ifdef DLT_FRELAY
192 { fr_if_print, DLT_FRELAY },
193 #endif
194 #ifdef DLT_SUNATM
195 { sunatm_if_print, DLT_SUNATM },
196 #endif
197 #ifdef DLT_IP_OVER_FC
198 { ipfc_if_print, DLT_IP_OVER_FC },
199 #endif
200 #ifdef DLT_PRISM_HEADER
201 { prism_if_print, DLT_PRISM_HEADER },
202 #endif
203 #ifdef DLT_IEEE802_11_RADIO
204 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO },
205 #endif
206 #ifdef DLT_ENC
207 { enc_if_print, DLT_ENC },
208 #endif
209 #ifdef DLT_APPLE_IP_OVER_IEEE1394
210 { ap1394_if_print, DLT_APPLE_IP_OVER_IEEE1394 },
211 #endif
212 { NULL, 0 },
213 };
214
215 static if_printer
216 lookup_printer(int type)
217 {
218 struct printer *p;
219
220 for (p = printers; p->f; ++p)
221 if (type == p->type)
222 return p->f;
223
224 return NULL;
225 /* NOTREACHED */
226 }
227
228 static pcap_t *pd;
229
230 extern int optind;
231 extern int opterr;
232 extern char *optarg;
233
234 struct print_info {
235 if_printer printer;
236 };
237
238 struct dump_info {
239 char *WFileName;
240 pcap_t *pd;
241 pcap_dumper_t *p;
242 };
243
244 static void
245 show_dlts_and_exit(pcap_t *pd)
246 {
247 int n_dlts;
248 int *dlts = 0;
249 const char *dlt_name;
250
251 n_dlts = pcap_list_datalinks(pd, &dlts);
252 if (n_dlts < 0)
253 error("%s", pcap_geterr(pd));
254 else if (n_dlts == 0 || !dlts)
255 error("No data link types.");
256
257 (void) fprintf(stderr, "Data link types (use option -y to set):\n");
258
259 while (--n_dlts >= 0) {
260 dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
261 if (dlt_name != NULL) {
262 (void) fprintf(stderr, " %s (%s)", dlt_name,
263 pcap_datalink_val_to_description(dlts[n_dlts]));
264
265 /*
266 * OK, does tcpdump handle that type?
267 */
268 if (lookup_printer(dlts[n_dlts]) == NULL)
269 (void) fprintf(stderr, " (not supported)");
270 putchar('\n');
271 } else {
272 (void) fprintf(stderr, " DLT %d (not supported)\n",
273 dlts[n_dlts]);
274 }
275 }
276 free(dlts);
277 exit(0);
278 }
279
280 /*
281 * Set up flags that might or might not be supported depending on the
282 * version of libpcap we're using.
283 */
284 #ifdef WIN32
285 #define B_FLAG "B:"
286 #define B_FLAG_USAGE " [ -B size ]"
287 #else /* WIN32 */
288 #define B_FLAG
289 #define B_FLAG_USAGE
290 #endif /* WIN32 */
291
292 #ifdef HAVE_PCAP_FINDALLDEVS
293 #define D_FLAG "D"
294 #else
295 #define D_FLAG
296 #endif
297
298 #ifdef HAVE_PCAP_DUMP_FLUSH
299 #define U_FLAG "U"
300 #else
301 #define U_FLAG
302 #endif
303
304 int
305 main(int argc, char **argv)
306 {
307 register int cnt, op, i;
308 bpf_u_int32 localnet, netmask;
309 register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
310 pcap_handler callback;
311 int type;
312 struct bpf_program fcode;
313 #ifndef WIN32
314 RETSIGTYPE (*oldhandler)(int);
315 #endif
316 struct print_info printinfo;
317 struct dump_info dumpinfo;
318 u_char *pcap_userdata;
319 char ebuf[PCAP_ERRBUF_SIZE];
320 #ifdef HAVE_PCAP_FINDALLDEVS
321 pcap_if_t *devpointer;
322 int devnum;
323 #endif
324 int status;
325 #ifdef WIN32
326 u_int UserBufferSize = 1000000;
327 if(wsockinit() != 0) return 1;
328 #endif /* WIN32 */
329
330 cnt = -1;
331 device = NULL;
332 infile = NULL;
333 RFileName = NULL;
334 WFileName = NULL;
335 if ((cp = strrchr(argv[0], '/')) != NULL)
336 program_name = cp + 1;
337 else
338 program_name = argv[0];
339
340 if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
341 error("%s", ebuf);
342
343 #ifdef LIBSMI
344 smiInit("tcpdump");
345 #endif
346
347 opterr = 0;
348 while (
349 (op = getopt(argc, argv, "aA" B_FLAG "c:C:d" D_FLAG "eE:fF:i:lLm:nNOpqr:Rs:StT:u" U_FLAG "vw:xXy:Y")) != -1)
350 switch (op) {
351
352 case 'a':
353 /* compatibility for old -a */
354 break;
355
356 case 'A':
357 ++xflag;
358 ++Xflag;
359 ++Aflag;
360 break;
361
362 #ifdef WIN32
363 case 'B':
364 UserBufferSize = atoi(optarg)*1024;
365 if (UserBufferSize < 0)
366 error("invalid packet buffer size %s", optarg);
367 break;
368 #endif /* WIN32 */
369
370 case 'c':
371 cnt = atoi(optarg);
372 if (cnt <= 0)
373 error("invalid packet count %s", optarg);
374 break;
375
376 case 'C':
377 Cflag = atoi(optarg) * 1000000;
378 if (Cflag < 0)
379 error("invalid file size %s", optarg);
380 break;
381
382 case 'd':
383 ++dflag;
384 break;
385
386 #ifdef HAVE_PCAP_FINDALLDEVS
387 case 'D':
388 if (pcap_findalldevs(&devpointer, ebuf) < 0)
389 error("%s", ebuf);
390 else {
391 for (i = 0; devpointer != 0; i++) {
392 printf("%d.%s", i+1, devpointer->name);
393 if (devpointer->description != NULL)
394 printf(" (%s)", devpointer->description);
395 printf("\n");
396 devpointer = devpointer->next;
397 }
398 }
399 return 0;
400 #endif /* HAVE_PCAP_FINDALLDEVS */
401
402 case 'L':
403 Lflag++;
404 break;
405
406 case 'e':
407 ++eflag;
408 break;
409
410 case 'E':
411 #ifndef HAVE_LIBCRYPTO
412 warning("crypto code not compiled in");
413 #endif
414 espsecret = optarg;
415 break;
416
417 case 'f':
418 ++fflag;
419 break;
420
421 case 'F':
422 infile = optarg;
423 break;
424
425 case 'i':
426 if (optarg[0] == '0' && optarg[1] == 0)
427 error("Invalid adapter index");
428
429 #ifdef HAVE_PCAP_FINDALLDEVS
430 /*
431 * If the argument is a number, treat it as
432 * an index into the list of adapters, as
433 * printed by "tcpdump -D".
434 *
435 * This should be OK on UNIX systems, as interfaces
436 * shouldn't have names that begin with digits.
437 * It can be useful on Windows, where more than
438 * one interface can have the same name.
439 */
440 if ((devnum = atoi(optarg)) != 0) {
441 if (devnum < 0)
442 error("Invalid adapter index");
443
444 if (pcap_findalldevs(&devpointer, ebuf) < 0)
445 error("%s", ebuf);
446 else {
447 for (i = 0; i < devnum-1; i++){
448 devpointer = devpointer->next;
449 if (devpointer == NULL)
450 error("Invalid adapter index");
451 }
452 }
453 device = devpointer->name;
454 break;
455 }
456 #endif /* HAVE_PCAP_FINDALLDEVS */
457 device = optarg;
458 break;
459
460 case 'l':
461 #ifdef WIN32
462 /*
463 * _IOLBF is the same as _IOFBF in Microsoft's C
464 * libraries; the only alternative they offer
465 * is _IONBF.
466 *
467 * XXX - this should really be checking for MSVC++,
468 * not WIN32, if, for example, MinGW has its own
469 * C library that is more UNIX-compatible.
470 */
471 setvbuf(stdout, NULL, _IONBF, 0);
472 #else /* WIN32 */
473 #ifdef HAVE_SETLINEBUF
474 setlinebuf(stdout);
475 #else
476 setvbuf(stdout, NULL, _IOLBF, 0);
477 #endif
478 #endif /* WIN32 */
479 break;
480
481 case 'n':
482 ++nflag;
483 break;
484
485 case 'N':
486 ++Nflag;
487 break;
488
489 case 'm':
490 #ifdef LIBSMI
491 if (smiLoadModule(optarg) == 0) {
492 error("could not load MIB module %s", optarg);
493 }
494 sflag = 1;
495 #else
496 (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
497 program_name, optarg);
498 (void)fprintf(stderr, "(no libsmi support)\n");
499 #endif
500 break;
501
502 case 'O':
503 Oflag = 0;
504 break;
505
506 case 'p':
507 ++pflag;
508 break;
509
510 case 'q':
511 ++qflag;
512 break;
513
514 case 'r':
515 RFileName = optarg;
516 break;
517
518 case 'R':
519 Rflag = 0;
520 break;
521
522 case 's': {
523 char *end;
524
525 snaplen = strtol(optarg, &end, 0);
526 if (optarg == end || *end != '\0'
527 || snaplen < 0 || snaplen > 65535)
528 error("invalid snaplen %s", optarg);
529 else if (snaplen == 0)
530 snaplen = 65535;
531 break;
532 }
533
534 case 'S':
535 ++Sflag;
536 break;
537
538 case 't':
539 --tflag;
540 break;
541
542 case 'T':
543 if (strcasecmp(optarg, "vat") == 0)
544 packettype = PT_VAT;
545 else if (strcasecmp(optarg, "wb") == 0)
546 packettype = PT_WB;
547 else if (strcasecmp(optarg, "rpc") == 0)
548 packettype = PT_RPC;
549 else if (strcasecmp(optarg, "rtp") == 0)
550 packettype = PT_RTP;
551 else if (strcasecmp(optarg, "rtcp") == 0)
552 packettype = PT_RTCP;
553 else if (strcasecmp(optarg, "snmp") == 0)
554 packettype = PT_SNMP;
555 else if (strcasecmp(optarg, "cnfp") == 0)
556 packettype = PT_CNFP;
557 else if (strcasecmp(optarg, "tftp") == 0)
558 packettype = PT_TFTP;
559 else if (strcasecmp(optarg, "aodv") == 0)
560 packettype = PT_AODV;
561 else
562 error("unknown packet type `%s'", optarg);
563 break;
564
565 case 'u':
566 ++uflag;
567 break;
568
569 #ifdef HAVE_PCAP_DUMP_FLUSH
570 case 'U':
571 ++Uflag;
572 break;
573 #endif
574
575 case 'v':
576 ++vflag;
577 break;
578
579 case 'w':
580 WFileName = optarg;
581 break;
582
583 case 'x':
584 ++xflag;
585 break;
586
587 case 'X':
588 ++xflag;
589 ++Xflag;
590 break;
591
592 case 'y':
593 dlt_name = optarg;
594 dlt = pcap_datalink_name_to_val(dlt_name);
595 if (dlt < 0)
596 error("invalid data link type %s", dlt_name);
597 break;
598
599 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
600 case 'Y':
601 {
602 /* Undocumented flag */
603 #ifdef HAVE_PCAP_DEBUG
604 extern int pcap_debug;
605 pcap_debug = 1;
606 #else
607 extern int yydebug;
608 yydebug = 1;
609 #endif
610 }
611 break;
612 #endif
613 default:
614 usage();
615 /* NOTREACHED */
616 }
617
618 if (tflag > 0)
619 thiszone = gmt2local(0);
620
621 if (RFileName != NULL) {
622 int dlt;
623 const char *dlt_name;
624
625 #ifndef WIN32
626 /*
627 * We don't need network access, so relinquish any set-UID
628 * or set-GID privileges we have (if any).
629 *
630 * We do *not* want set-UID privileges when opening a
631 * trace file, as that might let the user read other
632 * people's trace files (especially if we're set-UID
633 * root).
634 */
635 setuid(getuid());
636 #endif /* WIN32 */
637 pd = pcap_open_offline(RFileName, ebuf);
638 if (pd == NULL)
639 error("%s", ebuf);
640 dlt = pcap_datalink(pd);
641 dlt_name = pcap_datalink_val_to_name(dlt);
642 if (dlt_name == NULL) {
643 fprintf(stderr, "reading from file %s, link-type %u\n",
644 RFileName, dlt);
645 } else {
646 fprintf(stderr,
647 "reading from file %s, link-type %s (%s)\n",
648 RFileName, dlt_name,
649 pcap_datalink_val_to_description(dlt));
650 }
651 localnet = 0;
652 netmask = 0;
653 if (fflag != 0)
654 error("-f and -r options are incompatible");
655 } else {
656 if (device == NULL) {
657 device = pcap_lookupdev(ebuf);
658 if (device == NULL)
659 error("%s", ebuf);
660 }
661 #ifdef WIN32
662 if(IsTextUnicode(device,
663 wcslen((short*)device), // Device always ends with a double \0, so this way to determine its
664 // length should be always valid
665 NULL))
666 {
667 fprintf(stderr, "%s: listening on %ws\n", program_name, device);
668 }
669 else
670 {
671 fprintf(stderr, "%s: listening on %s\n", program_name, device);
672 }
673
674 fflush(stderr);
675 #endif /* WIN32 */
676 *ebuf = '\0';
677 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
678 if (pd == NULL)
679 error("%s", ebuf);
680 else if (*ebuf)
681 warning("%s", ebuf);
682 #ifdef WIN32
683 if(UserBufferSize != 1000000)
684 if(pcap_setbuff(pd, UserBufferSize)==-1){
685 error("%s", pcap_geterr(pd));
686 }
687 #endif /* WIN32 */
688 if (Lflag)
689 show_dlts_and_exit(pd);
690 if (dlt >= 0) {
691 #ifdef HAVE_PCAP_SET_DATALINK
692 if (pcap_set_datalink(pd, dlt) < 0)
693 error("%s", pcap_geterr(pd));
694 #else
695 /*
696 * We don't actually support changing the
697 * data link type, so we only let them
698 * set it to what it already is.
699 */
700 if (dlt != pcap_datalink(pd)) {
701 error("%s is not one of the DLTs supported by this device\n",
702 dlt_name);
703 }
704 #endif
705 (void)fprintf(stderr, "%s: data link type %s\n",
706 program_name, dlt_name);
707 (void)fflush(stderr);
708 }
709 i = pcap_snapshot(pd);
710 if (snaplen < i) {
711 warning("snaplen raised from %d to %d", snaplen, i);
712 snaplen = i;
713 }
714 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
715 localnet = 0;
716 netmask = 0;
717 warning("%s", ebuf);
718 }
719 /*
720 * Let user own process after socket has been opened.
721 */
722 #ifndef WIN32
723 setuid(getuid());
724 #endif /* WIN32 */
725 }
726 if (infile)
727 cmdbuf = read_infile(infile);
728 else
729 cmdbuf = copy_argv(&argv[optind]);
730
731 if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
732 error("%s", pcap_geterr(pd));
733 if (dflag) {
734 bpf_dump(&fcode, dflag);
735 pcap_close(pd);
736 exit(0);
737 }
738 init_addrtoname(localnet, netmask);
739
740 #ifndef WIN32
741 (void)setsignal(SIGPIPE, cleanup);
742 #endif /* WIN32 */
743 (void)setsignal(SIGTERM, cleanup);
744 (void)setsignal(SIGINT, cleanup);
745 /* Cooperate with nohup(1) */
746 #ifndef WIN32
747 if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
748 (void)setsignal(SIGHUP, oldhandler);
749 #endif /* WIN32 */
750
751 if (pcap_setfilter(pd, &fcode) < 0)
752 error("%s", pcap_geterr(pd));
753 if (WFileName) {
754 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
755 if (p == NULL)
756 error("%s", pcap_geterr(pd));
757 if (Cflag != 0) {
758 callback = dump_packet_and_trunc;
759 dumpinfo.WFileName = WFileName;
760 dumpinfo.pd = pd;
761 dumpinfo.p = p;
762 pcap_userdata = (u_char *)&dumpinfo;
763 } else {
764 callback = dump_packet;
765 pcap_userdata = (u_char *)p;
766 }
767 } else {
768 type = pcap_datalink(pd);
769 printinfo.printer = lookup_printer(type);
770 if (printinfo.printer == NULL) {
771 dlt_name = pcap_datalink_val_to_name(type);
772 if (dlt_name != NULL)
773 error("unsupported data link type %s", dlt_name);
774 else
775 error("unsupported data link type %d", type);
776 }
777 callback = print_packet;
778 pcap_userdata = (u_char *)&printinfo;
779 }
780 #ifdef SIGINFO
781 (void)setsignal(SIGINFO, requestinfo);
782 #endif
783 #ifndef WIN32
784 if (RFileName == NULL) {
785 int dlt;
786 const char *dlt_name;
787
788 if (!vflag && !WFileName) {
789 (void)fprintf(stderr,
790 "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
791 program_name);
792 } else
793 (void)fprintf(stderr, "%s: ", program_name);
794 dlt = pcap_datalink(pd);
795 dlt_name = pcap_datalink_val_to_name(dlt);
796 if (dlt_name == NULL) {
797 (void)fprintf(stderr, "listening on %s, link-type %u, capture size %u bytes\n",
798 device, dlt, snaplen);
799 } else {
800 (void)fprintf(stderr, "listening on %s, link-type %s (%s), capture size %u bytes\n",
801 device, dlt_name,
802 pcap_datalink_val_to_description(dlt), snaplen);
803 }
804 (void)fflush(stderr);
805 }
806 #endif /* WIN32 */
807 status = pcap_loop(pd, cnt, callback, pcap_userdata);
808 if (WFileName == NULL) {
809 /*
810 * We're printing packets. Flush the printed output,
811 * so it doesn't get intermingled with error output.
812 */
813 if (status == -2) {
814 /*
815 * We got interrupted, so perhaps we didn't
816 * manage to finish a line we were printing.
817 * Print an extra newline, just in case.
818 */
819 putchar('\n');
820 }
821 (void)fflush(stdout);
822 }
823 if (status == -1) {
824 /*
825 * Error. Report it.
826 */
827 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
828 program_name, pcap_geterr(pd));
829 }
830 if (RFileName == NULL) {
831 /*
832 * We're doing a live capture. Report the capture
833 * statistics.
834 */
835 info(1);
836 }
837 pcap_close(pd);
838 exit(status == -1 ? 1 : 0);
839 }
840
841 /* make a clean exit on interrupts */
842 static RETSIGTYPE
843 cleanup(int signo _U_)
844 {
845 #ifdef HAVE_PCAP_BREAKLOOP
846 /*
847 * We have "pcap_breakloop()"; use it, so that we do as little
848 * as possible in the signal handler (it's probably not safe
849 * to do anything with standard I/O streams in a signal handler -
850 * the ANSI C standard doesn't say it is).
851 */
852 pcap_breakloop(pd);
853 #else
854 /*
855 * We don't have "pcap_breakloop()"; this isn't safe, but
856 * it's the best we can do. Print the summary if we're
857 * not reading from a savefile - i.e., if we're doing a
858 * live capture - and exit.
859 */
860 if (pd != NULL && pcap_file(pd) == NULL) {
861 /*
862 * We got interrupted, so perhaps we didn't
863 * manage to finish a line we were printing.
864 * Print an extra newline, just in case.
865 */
866 putchar('\n');
867 (void)fflush(stdout);
868 info(1);
869 }
870 exit(0);
871 #endif
872 }
873
874 static void
875 info(register int verbose)
876 {
877 struct pcap_stat stat;
878
879 if (pcap_stats(pd, &stat) < 0) {
880 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
881 return;
882 }
883
884 if (!verbose)
885 fprintf(stderr, "%s: ", program_name);
886
887 (void)fprintf(stderr, "%u packets captured", packets_captured);
888 if (!verbose)
889 fputs(", ", stderr);
890 else
891 putc('\n', stderr);
892 (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
893 if (!verbose)
894 fputs(", ", stderr);
895 else
896 putc('\n', stderr);
897 (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
898 infoprint = 0;
899 }
900
901 static void
902 reverse(char *s)
903 {
904 int i, j, c;
905
906 for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
907 c = s[i];
908 s[i] = s[j];
909 s[j] = c;
910 }
911 }
912
913
914 static void
915 swebitoa(unsigned int n, char *s)
916 {
917 unsigned int i;
918
919 i = 0;
920 do {
921 s[i++] = n % 10 + '0';
922 } while ((n /= 10) > 0);
923
924 s[i] = '\0';
925 reverse(s);
926 }
927
928 static void
929 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
930 {
931 struct dump_info *dump_info;
932 static uint cnt = 2;
933 char *name;
934
935 ++packets_captured;
936
937 ++infodelay;
938
939 dump_info = (struct dump_info *)user;
940
941 /*
942 * XXX - this won't prevent capture files from getting
943 * larger than Cflag - the last packet written to the
944 * file could put it over Cflag.
945 */
946 if (ftell((FILE *)dump_info->p) > Cflag) {
947 /*
948 * Close the current file and open a new one.
949 */
950 pcap_dump_close(dump_info->p);
951 if (cnt >= 1000)
952 error("too many output files");
953 name = (char *) malloc(strlen(dump_info->WFileName) + 4);
954 if (name == NULL)
955 error("dump_packet_and_trunc: malloc");
956 strcpy(name, dump_info->WFileName);
957 swebitoa(cnt, name + strlen(dump_info->WFileName));
958 cnt++;
959 dump_info->p = pcap_dump_open(dump_info->pd, name);
960 free(name);
961 if (dump_info->p == NULL)
962 error("%s", pcap_geterr(pd));
963 }
964
965 pcap_dump((u_char *)dump_info->p, h, sp);
966 #ifdef HAVE_PCAP_DUMP_FLUSH
967 if (Uflag)
968 pcap_dump_flush(dump_info->p);
969 #endif
970
971 --infodelay;
972 if (infoprint)
973 info(0);
974 }
975
976 static void
977 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
978 {
979 ++packets_captured;
980
981 ++infodelay;
982
983 pcap_dump(user, h, sp);
984 #ifdef HAVE_PCAP_DUMP_FLUSH
985 if (Uflag)
986 pcap_dump_flush((pcap_dumper_t *)user);
987 #endif
988
989 --infodelay;
990 if (infoprint)
991 info(0);
992 }
993
994 static void
995 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
996 {
997 struct print_info *print_info;
998 u_int hdrlen;
999
1000 ++packets_captured;
1001
1002 ++infodelay;
1003 ts_print(&h->ts);
1004
1005 print_info = (struct print_info *)user;
1006
1007 /*
1008 * Some printers want to check that they're not walking off the
1009 * end of the packet.
1010 * Rather than pass it all the way down, we set this global.
1011 */
1012 snapend = sp + h->caplen;
1013
1014 hdrlen = (*print_info->printer)(h, sp);
1015 if (xflag) {
1016 /*
1017 * Print the raw packet data.
1018 */
1019 if (xflag > 1) {
1020 /*
1021 * Include the link-layer header.
1022 */
1023 default_print(sp, h->caplen);
1024 } else {
1025 /*
1026 * Don't include the link-layer header - and if
1027 * we have nothing past the link-layer header,
1028 * print nothing.
1029 */
1030 if (h->caplen > hdrlen)
1031 default_print(sp + hdrlen,
1032 h->caplen - hdrlen);
1033 }
1034 }
1035
1036 putchar('\n');
1037
1038 --infodelay;
1039 if (infoprint)
1040 info(0);
1041 }
1042
1043 #ifdef WIN32
1044 /*
1045 * XXX - there should really be libpcap calls to get the version
1046 * number as a string (the string would be generated from #defines
1047 * at run time, so that it's not generated from string constants
1048 * in the library, as, on many UNIX systems, those constants would
1049 * be statically linked into the application executable image, and
1050 * would thus reflect the version of libpcap on the system on
1051 * which the application was *linked*, not the system on which it's
1052 * *running*.
1053 *
1054 * That routine should be documented, unlike the "version[]"
1055 * string, so that UNIX vendors providing their own libpcaps
1056 * don't omit it (as a couple of vendors have...).
1057 *
1058 * Packet.dll should perhaps also export a routine to return the
1059 * version number of the Packet.dll code, to supply the
1060 * "Wpcap_version" information on Windows.
1061 */
1062 char WDversion[]="current-cvs.tcpdump.org";
1063 char version[]="current-cvs.tcpdump.org";
1064 char pcap_version[]="current-cvs.tcpdump.org";
1065 char Wpcap_version[]="3.0 alpha";
1066 #endif
1067
1068 /*
1069 * By default, print the specified data out in hex.
1070 */
1071 void
1072 default_print(register const u_char *bp, register u_int length)
1073 {
1074 ascii_print("\n\t", bp, length); /* pass on lf and identation string */
1075 }
1076
1077 #ifdef SIGINFO
1078 RETSIGTYPE requestinfo(int signo _U_)
1079 {
1080 if (infodelay)
1081 ++infoprint;
1082 else
1083 info(0);
1084 }
1085 #endif
1086
1087 static void
1088 usage(void)
1089 {
1090 extern char version[];
1091 #ifndef HAVE_PCAP_LIB_VERSION
1092 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
1093 extern char pcap_version[];
1094 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1095 static char pcap_version[] = "unknown";
1096 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1097 #endif /* HAVE_PCAP_LIB_VERSION */
1098
1099 #ifdef HAVE_PCAP_LIB_VERSION
1100 (void)fprintf(stderr, "%s version %s\n", program_name, version);
1101 (void)fprintf(stderr, "%s\n", pcap_lib_version());
1102 #else /* HAVE_PCAP_LIB_VERSION */
1103 #ifdef WIN32
1104 (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1105 (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1106 #else /* WIN32 */
1107 (void)fprintf(stderr, "%s version %s\n", program_name, version);
1108 (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1109 #endif /* WIN32 */
1110 #endif /* HAVE_PCAP_LIB_VERSION */
1111 (void)fprintf(stderr,
1112 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1113 (void)fprintf(stderr,
1114 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
1115 (void)fprintf(stderr,
1116 "\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
1117 (void)fprintf(stderr,
1118 "\t\t[ expression ]\n");
1119 exit(1);
1120 }
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