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 /*
29 * tcpdump - dump traffic on a network
30 *
31 * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
32 * Mercilessly hacked and occasionally improved since then via the
33 * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
34 */
35
36 #ifdef HAVE_CONFIG_H
37 #include <config.h>
38 #endif
39
40 /*
41 * Some older versions of Mac OS X may ship pcap.h from libpcap 0.6 with a
42 * libpcap based on 0.8. That means it has pcap_findalldevs() but the
43 * header doesn't define pcap_if_t, meaning that we can't actually *use*
44 * pcap_findalldevs().
45 */
46 #ifdef HAVE_PCAP_FINDALLDEVS
47 #ifndef HAVE_PCAP_IF_T
48 #undef HAVE_PCAP_FINDALLDEVS
49 #endif
50 #endif
51
52 #include "netdissect-stdinc.h"
53
54 /*
55 * This must appear after including netdissect-stdinc.h, so that _U_ is
56 * defined.
57 */
58 #ifndef lint
59 static const char copyright[] _U_ =
60 "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
61 The Regents of the University of California. All rights reserved.\n";
62 #endif
63
64 #include <sys/stat.h>
65
66 #ifdef HAVE_FCNTL_H
67 #include <fcntl.h>
68 #endif
69
70 #ifdef HAVE_LIBCRYPTO
71 #include <openssl/crypto.h>
72 #endif
73
74 #ifdef HAVE_GETOPT_LONG
75 #include <getopt.h>
76 #else
77 #include "missing/getopt_long.h"
78 #endif
79 /* Capsicum-specific code requires macros from <net/bpf.h>, which will fail
80 * to compile if <pcap.h> has already been included; including the headers
81 * in the opposite order works fine. For the most part anyway, because in
82 * FreeBSD <pcap/pcap.h> declares bpf_dump() instead of <net/bpf.h>. Thus
83 * interface.h takes care of it later to avoid a compiler warning.
84 */
85 #ifdef HAVE_CAPSICUM
86 #include <sys/capsicum.h>
87 #include <sys/ioccom.h>
88 #include <net/bpf.h>
89 #include <libgen.h>
90 #ifdef HAVE_CASPER
91 #include <libcasper.h>
92 #include <casper/cap_dns.h>
93 #include <sys/nv.h>
94 #endif /* HAVE_CASPER */
95 #endif /* HAVE_CAPSICUM */
96 #ifdef HAVE_PCAP_OPEN
97 /*
98 * We found pcap_open() in the capture library, so we'll be using
99 * the remote capture APIs; define PCAP_REMOTE before we include pcap.h,
100 * so we get those APIs declared, and the types and #defines that they
101 * use defined.
102 *
103 * WinPcap's headers require that PCAP_REMOTE be defined in order to get
104 * remote-capture APIs declared and types and #defines that they use
105 * defined.
106 *
107 * (Versions of libpcap with those APIs, and thus Npcap, which is based on
108 * those versions of libpcap, don't require it.)
109 */
110 #define HAVE_REMOTE
111 #endif
112 #include <pcap.h>
113 #include <signal.h>
114 #include <stdio.h>
115 #include <stdarg.h>
116 #include <stdlib.h>
117 #include <string.h>
118 #include <limits.h>
119 #ifdef _WIN32
120 #include <windows.h>
121 #else
122 #include <sys/time.h>
123 #include <sys/wait.h>
124 #include <sys/resource.h>
125 #include <pwd.h>
126 #include <grp.h>
127 #endif /* _WIN32 */
128
129 /*
130 * Pathname separator.
131 * Use this in pathnames, but do *not* use it in URLs.
132 */
133 #ifdef _WIN32
134 #define PATH_SEPARATOR '\\'
135 #else
136 #define PATH_SEPARATOR '/'
137 #endif
138
139 /* capabilities convenience library */
140 /* If a code depends on HAVE_LIBCAP_NG, it depends also on HAVE_CAP_NG_H.
141 * If HAVE_CAP_NG_H is not defined, undefine HAVE_LIBCAP_NG.
142 * Thus, the later tests are done only on HAVE_LIBCAP_NG.
143 */
144 #ifdef HAVE_LIBCAP_NG
145 #ifdef HAVE_CAP_NG_H
146 #include <cap-ng.h>
147 #else
148 #undef HAVE_LIBCAP_NG
149 #endif /* HAVE_CAP_NG_H */
150 #endif /* HAVE_LIBCAP_NG */
151
152 #ifdef __FreeBSD__
153 #include <sys/sysctl.h>
154 #endif /* __FreeBSD__ */
155
156 #include "netdissect-stdinc.h"
157 #include "netdissect.h"
158 #include "interface.h"
159 #include "addrtoname.h"
160 #include "machdep.h"
161 #include "pcap-missing.h"
162 #include "ascii_strcasecmp.h"
163
164 #include "print.h"
165
166 #include "diag-control.h"
167
168 #include "fptype.h"
169
170 #ifndef PATH_MAX
171 #define PATH_MAX 1024
172 #endif
173
174 #if defined(SIGINFO)
175 #define SIGNAL_REQ_INFO SIGINFO
176 #elif defined(SIGUSR1)
177 #define SIGNAL_REQ_INFO SIGUSR1
178 #endif
179
180 #if defined(HAVE_PCAP_DUMP_FLUSH) && defined(SIGUSR2)
181 #define SIGNAL_FLUSH_PCAP SIGUSR2
182 #endif
183
184 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
185 static int Bflag; /* buffer size */
186 #endif
187 #ifdef HAVE_PCAP_DUMP_FTELL64
188 static int64_t Cflag; /* rotate dump files after this many bytes */
189 #else
190 static long Cflag; /* rotate dump files after this many bytes */
191 #endif
192 static int Cflag_count; /* Keep track of which file number we're writing */
193 #ifdef HAVE_PCAP_FINDALLDEVS
194 static int Dflag; /* list available devices and exit */
195 #endif
196 #ifdef HAVE_PCAP_FINDALLDEVS_EX
197 static char *remote_interfaces_source; /* list available devices from this source and exit */
198 #endif
199
200 /*
201 * This is exported because, in some versions of libpcap, if libpcap
202 * is built with optimizer debugging code (which is *NOT* the default
203 * configuration!), the library *imports*(!) a variable named dflag,
204 * under the expectation that tcpdump is exporting it, to govern
205 * how much debugging information to print when optimizing
206 * the generated BPF code.
207 *
208 * This is a horrible hack; newer versions of libpcap don't import
209 * dflag but, instead, *if* built with optimizer debugging code,
210 * *export* a routine to set that flag.
211 */
212 extern int dflag;
213 int dflag; /* print filter code */
214 static int Gflag; /* rotate dump files after this many seconds */
215 static int Gflag_count; /* number of files created with Gflag rotation */
216 static time_t Gflag_time; /* The last time_t the dump file was rotated. */
217 static int Lflag; /* list available data link types and exit */
218 static int Iflag; /* rfmon (monitor) mode */
219 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
220 static int Jflag; /* list available time stamp types */
221 static int jflag = -1; /* packet time stamp source */
222 #endif
223 static int lflag; /* line-buffered output */
224 static int pflag; /* don't go promiscuous */
225 #ifdef HAVE_PCAP_SETDIRECTION
226 static int Qflag = -1; /* restrict captured packet by send/receive direction */
227 #endif
228 #ifdef HAVE_PCAP_DUMP_FLUSH
229 static int Uflag; /* "unbuffered" output of dump files */
230 #endif
231 static int Wflag; /* recycle output files after this number of files */
232 static int WflagChars;
233 static char *zflag = NULL; /* compress each savefile using a specified command (like gzip or bzip2) */
234 static int timeout = 1000; /* default timeout = 1000 ms = 1 s */
235 #ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
236 static int immediate_mode;
237 #endif
238 static int count_mode;
239
240 static int infodelay;
241 static int infoprint;
242
243 char *program_name;
244
245 /*
246 * #ifdef HAVE_CASPER
247 * cap_channel_t *capdns;
248 * #endif
249 */
250
251 /* Forwards */
252 static NORETURN void error(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
253 static void warning(FORMAT_STRING(const char *), ...) PRINTFLIKE(1, 2);
254 static NORETURN void exit_tcpdump(int);
255 static void (*setsignal (int sig, void (*func)(int)))(int);
256 static void cleanup(int);
257 static void child_cleanup(int);
258 static void print_version(FILE *);
259 static void print_usage(FILE *);
260 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
261 static NORETURN void show_tstamp_types_and_exit(pcap_t *, const char *device);
262 #endif
263 static NORETURN void show_dlts_and_exit(pcap_t *, const char *device);
264 #ifdef HAVE_PCAP_FINDALLDEVS
265 static NORETURN void show_devices_and_exit(void);
266 #endif
267 #ifdef HAVE_PCAP_FINDALLDEVS_EX
268 static NORETURN void show_remote_devices_and_exit(void);
269 #endif
270
271 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
272 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
273 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
274 static void droproot(const char *, const char *);
275
276 #ifdef SIGNAL_REQ_INFO
277 static void requestinfo(int);
278 #endif
279
280 #ifdef SIGNAL_FLUSH_PCAP
281 static void flushpcap(int);
282 #endif
283
284 #ifdef _WIN32
285 static HANDLE timer_handle = INVALID_HANDLE_VALUE;
286 static void CALLBACK verbose_stats_dump(PVOID param, BOOLEAN timer_fired);
287 #else /* _WIN32 */
288 static void verbose_stats_dump(int sig);
289 #endif /* _WIN32 */
290
291 static void info(int);
292 static u_int packets_captured;
293
294 #ifdef HAVE_PCAP_FINDALLDEVS
295 static const struct tok status_flags[] = {
296 #ifdef PCAP_IF_UP
297 { PCAP_IF_UP, "Up" },
298 #endif
299 #ifdef PCAP_IF_RUNNING
300 { PCAP_IF_RUNNING, "Running" },
301 #endif
302 { PCAP_IF_LOOPBACK, "Loopback" },
303 #ifdef PCAP_IF_WIRELESS
304 { PCAP_IF_WIRELESS, "Wireless" },
305 #endif
306 { 0, NULL }
307 };
308 #endif
309
310 static pcap_t *pd;
311 static pcap_dumper_t *pdd = NULL;
312
313 static int supports_monitor_mode;
314
315 extern int optind;
316 extern int opterr;
317 extern char *optarg;
318
319 struct dump_info {
320 char *WFileName;
321 char *CurrentFileName;
322 pcap_t *pd;
323 pcap_dumper_t *pdd;
324 netdissect_options *ndo;
325 #ifdef HAVE_CAPSICUM
326 int dirfd;
327 #endif
328 };
329
330 #if defined(HAVE_PCAP_SET_PARSER_DEBUG)
331 /*
332 * We have pcap_set_parser_debug() in libpcap; declare it (it's not declared
333 * by any libpcap header, because it's a special hack, only available if
334 * libpcap was configured to include it, and only intended for use by
335 * libpcap developers trying to debug the parser for filter expressions).
336 */
337 #ifdef _WIN32
338 __declspec(dllimport)
339 #else /* _WIN32 */
340 extern
341 #endif /* _WIN32 */
342 void pcap_set_parser_debug(int);
343 #elif defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
344 /*
345 * We don't have pcap_set_parser_debug() in libpcap, but we do have
346 * pcap_debug or yydebug. Make a local version of pcap_set_parser_debug()
347 * to set the flag, and define HAVE_PCAP_SET_PARSER_DEBUG.
348 */
349 static void
pcap_set_parser_debug(int value)350 pcap_set_parser_debug(int value)
351 {
352 #ifdef HAVE_PCAP_DEBUG
353 extern int pcap_debug;
354
355 pcap_debug = value;
356 #else /* HAVE_PCAP_DEBUG */
357 extern int yydebug;
358
359 yydebug = value;
360 #endif /* HAVE_PCAP_DEBUG */
361 }
362
363 #define HAVE_PCAP_SET_PARSER_DEBUG
364 #endif
365
366 #if defined(HAVE_PCAP_SET_OPTIMIZER_DEBUG)
367 /*
368 * We have pcap_set_optimizer_debug() in libpcap; declare it (it's not declared
369 * by any libpcap header, because it's a special hack, only available if
370 * libpcap was configured to include it, and only intended for use by
371 * libpcap developers trying to debug the optimizer for filter expressions).
372 */
373 #ifdef _WIN32
374 __declspec(dllimport)
375 #else /* _WIN32 */
376 extern
377 #endif /* _WIN32 */
378 void pcap_set_optimizer_debug(int);
379 #endif
380
381 /* VARARGS */
382 static void
error(const char * fmt,...)383 error(const char *fmt, ...)
384 {
385 va_list ap;
386
387 (void)fprintf(stderr, "%s: ", program_name);
388 va_start(ap, fmt);
389 (void)vfprintf(stderr, fmt, ap);
390 va_end(ap);
391 if (*fmt) {
392 fmt += strlen(fmt);
393 if (fmt[-1] != '\n')
394 (void)fputc('\n', stderr);
395 }
396 exit_tcpdump(S_ERR_HOST_PROGRAM);
397 /* NOTREACHED */
398 }
399
400 /* VARARGS */
401 static void
warning(const char * fmt,...)402 warning(const char *fmt, ...)
403 {
404 va_list ap;
405
406 (void)fprintf(stderr, "%s: WARNING: ", program_name);
407 va_start(ap, fmt);
408 (void)vfprintf(stderr, fmt, ap);
409 va_end(ap);
410 if (*fmt) {
411 fmt += strlen(fmt);
412 if (fmt[-1] != '\n')
413 (void)fputc('\n', stderr);
414 }
415 }
416
417 static void
exit_tcpdump(int status)418 exit_tcpdump(int status)
419 {
420 nd_cleanup();
421 exit(status);
422 }
423
424 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
425 static void
show_tstamp_types_and_exit(pcap_t * pc,const char * device)426 show_tstamp_types_and_exit(pcap_t *pc, const char *device)
427 {
428 int n_tstamp_types;
429 int *tstamp_types = 0;
430 const char *tstamp_type_name;
431 int i;
432
433 n_tstamp_types = pcap_list_tstamp_types(pc, &tstamp_types);
434 if (n_tstamp_types < 0)
435 error("%s", pcap_geterr(pc));
436
437 if (n_tstamp_types == 0) {
438 fprintf(stderr, "Time stamp type cannot be set for %s\n",
439 device);
440 exit_tcpdump(S_SUCCESS);
441 }
442 fprintf(stderr, "Time stamp types for %s (use option -j to set):\n",
443 device);
444 for (i = 0; i < n_tstamp_types; i++) {
445 tstamp_type_name = pcap_tstamp_type_val_to_name(tstamp_types[i]);
446 if (tstamp_type_name != NULL) {
447 (void) fprintf(stderr, " %s (%s)\n", tstamp_type_name,
448 pcap_tstamp_type_val_to_description(tstamp_types[i]));
449 } else {
450 (void) fprintf(stderr, " %d\n", tstamp_types[i]);
451 }
452 }
453 pcap_free_tstamp_types(tstamp_types);
454 exit_tcpdump(S_SUCCESS);
455 }
456 #endif
457
458 static void
show_dlts_and_exit(pcap_t * pc,const char * device)459 show_dlts_and_exit(pcap_t *pc, const char *device)
460 {
461 int n_dlts, i;
462 int *dlts = 0;
463 const char *dlt_name;
464
465 n_dlts = pcap_list_datalinks(pc, &dlts);
466 if (n_dlts < 0)
467 error("%s", pcap_geterr(pc));
468 else if (n_dlts == 0 || !dlts)
469 error("No data link types.");
470
471 /*
472 * If the interface is known to support monitor mode, indicate
473 * whether these are the data link types available when not in
474 * monitor mode, if -I wasn't specified, or when in monitor mode,
475 * when -I was specified (the link-layer types available in
476 * monitor mode might be different from the ones available when
477 * not in monitor mode).
478 */
479 if (supports_monitor_mode)
480 (void) fprintf(stderr, "Data link types for %s %s (use option -y to set):\n",
481 device,
482 Iflag ? "when in monitor mode" : "when not in monitor mode");
483 else
484 (void) fprintf(stderr, "Data link types for %s (use option -y to set):\n",
485 device);
486
487 for (i = 0; i < n_dlts; i++) {
488 dlt_name = pcap_datalink_val_to_name(dlts[i]);
489 if (dlt_name != NULL) {
490 (void) fprintf(stderr, " %s (%s)", dlt_name,
491 pcap_datalink_val_to_description(dlts[i]));
492
493 /*
494 * OK, does tcpdump handle that type?
495 */
496 if (!has_printer(dlts[i]))
497 (void) fprintf(stderr, " (printing not supported)");
498 fprintf(stderr, "\n");
499 } else {
500 (void) fprintf(stderr, " DLT %d (printing not supported)\n",
501 dlts[i]);
502 }
503 }
504 #ifdef HAVE_PCAP_FREE_DATALINKS
505 pcap_free_datalinks(dlts);
506 #endif
507 exit_tcpdump(S_SUCCESS);
508 }
509
510 #ifdef HAVE_PCAP_FINDALLDEVS
511 static void
show_devices_and_exit(void)512 show_devices_and_exit(void)
513 {
514 pcap_if_t *dev, *devlist;
515 char ebuf[PCAP_ERRBUF_SIZE];
516 int i;
517
518 if (pcap_findalldevs(&devlist, ebuf) < 0)
519 error("%s", ebuf);
520 for (i = 0, dev = devlist; dev != NULL; i++, dev = dev->next) {
521 printf("%d.%s", i+1, dev->name);
522 if (dev->description != NULL)
523 printf(" (%s)", dev->description);
524 if (dev->flags != 0) {
525 printf(" [");
526 printf("%s", bittok2str(status_flags, "none", dev->flags));
527 #ifdef PCAP_IF_WIRELESS
528 if (dev->flags & PCAP_IF_WIRELESS) {
529 switch (dev->flags & PCAP_IF_CONNECTION_STATUS) {
530
531 case PCAP_IF_CONNECTION_STATUS_UNKNOWN:
532 printf(", Association status unknown");
533 break;
534
535 case PCAP_IF_CONNECTION_STATUS_CONNECTED:
536 printf(", Associated");
537 break;
538
539 case PCAP_IF_CONNECTION_STATUS_DISCONNECTED:
540 printf(", Not associated");
541 break;
542
543 case PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE:
544 break;
545 }
546 } else {
547 switch (dev->flags & PCAP_IF_CONNECTION_STATUS) {
548
549 case PCAP_IF_CONNECTION_STATUS_UNKNOWN:
550 printf(", Connection status unknown");
551 break;
552
553 case PCAP_IF_CONNECTION_STATUS_CONNECTED:
554 printf(", Connected");
555 break;
556
557 case PCAP_IF_CONNECTION_STATUS_DISCONNECTED:
558 printf(", Disconnected");
559 break;
560
561 case PCAP_IF_CONNECTION_STATUS_NOT_APPLICABLE:
562 break;
563 }
564 }
565 #endif
566 printf("]");
567 }
568 printf("\n");
569 }
570 pcap_freealldevs(devlist);
571 exit_tcpdump(S_SUCCESS);
572 }
573 #endif /* HAVE_PCAP_FINDALLDEVS */
574
575 #ifdef HAVE_PCAP_FINDALLDEVS_EX
576 static void
show_remote_devices_and_exit(void)577 show_remote_devices_and_exit(void)
578 {
579 pcap_if_t *dev, *devlist;
580 char ebuf[PCAP_ERRBUF_SIZE];
581 int i;
582
583 if (pcap_findalldevs_ex(remote_interfaces_source, NULL, &devlist,
584 ebuf) < 0)
585 error("%s", ebuf);
586 for (i = 0, dev = devlist; dev != NULL; i++, dev = dev->next) {
587 printf("%d.%s", i+1, dev->name);
588 if (dev->description != NULL)
589 printf(" (%s)", dev->description);
590 if (dev->flags != 0)
591 printf(" [%s]", bittok2str(status_flags, "none", dev->flags));
592 printf("\n");
593 }
594 pcap_freealldevs(devlist);
595 exit_tcpdump(S_SUCCESS);
596 }
597 #endif /* HAVE_PCAP_FINDALLDEVS */
598
599 /*
600 * Short options.
601 *
602 * Note that there we use all letters for short options except for g, k,
603 * o, and P, and those are used by other versions of tcpdump, and we should
604 * only use them for the same purposes that the other versions of tcpdump
605 * use them:
606 *
607 * macOS tcpdump uses -g to force non--v output for IP to be on one
608 * line, making it more "g"repable;
609 *
610 * macOS tcpdump uses -k to specify that packet comments in pcapng files
611 * should be printed;
612 *
613 * OpenBSD tcpdump uses -o to indicate that OS fingerprinting should be done
614 * for hosts sending TCP SYN packets;
615 *
616 * macOS tcpdump uses -P to indicate that -w should write pcapng rather
617 * than pcap files.
618 *
619 * macOS tcpdump also uses -Q to specify expressions that match packet
620 * metadata, including but not limited to the packet direction.
621 * The expression syntax is different from a simple "in|out|inout",
622 * and those expressions aren't accepted by macOS tcpdump, but the
623 * equivalents would be "in" = "dir=in", "out" = "dir=out", and
624 * "inout" = "dir=in or dir=out", and the parser could conceivably
625 * special-case "in", "out", and "inout" as expressions for backwards
626 * compatibility, so all is not (yet) lost.
627 */
628
629 /*
630 * Set up flags that might or might not be supported depending on the
631 * version of libpcap we're using.
632 */
633 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
634 #define B_FLAG "B:"
635 #define B_FLAG_USAGE " [ -B size ]"
636 #else /* defined(HAVE_PCAP_CREATE) || defined(_WIN32) */
637 #define B_FLAG
638 #define B_FLAG_USAGE
639 #endif /* defined(HAVE_PCAP_CREATE) || defined(_WIN32) */
640
641 #ifdef HAVE_PCAP_FINDALLDEVS
642 #define D_FLAG "D"
643 #else
644 #define D_FLAG
645 #endif
646
647 #ifdef HAVE_PCAP_CREATE
648 #define I_FLAG "I"
649 #else /* HAVE_PCAP_CREATE */
650 #define I_FLAG
651 #endif /* HAVE_PCAP_CREATE */
652
653 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
654 #define j_FLAG "j:"
655 #define j_FLAG_USAGE " [ -j tstamptype ]"
656 #define J_FLAG "J"
657 #else /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
658 #define j_FLAG
659 #define j_FLAG_USAGE
660 #define J_FLAG
661 #endif /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
662
663 #ifdef USE_LIBSMI
664 #define m_FLAG_USAGE "[ -m module ] ..."
665 #endif
666
667 #ifdef HAVE_PCAP_SETDIRECTION
668 #define Q_FLAG "Q:"
669 #define Q_FLAG_USAGE " [ -Q in|out|inout ]"
670 #else
671 #define Q_FLAG
672 #define Q_FLAG_USAGE
673 #endif
674
675 #ifdef HAVE_PCAP_DUMP_FLUSH
676 #define U_FLAG "U"
677 #else
678 #define U_FLAG
679 #endif
680
681 #define SHORTOPTS "aAb" B_FLAG "c:C:d" D_FLAG "eE:fF:G:hHi:" I_FLAG j_FLAG J_FLAG "KlLm:M:nNOpq" Q_FLAG "r:s:StT:u" U_FLAG "vV:w:W:xXy:Yz:Z:#"
682
683 /*
684 * Long options.
685 *
686 * We do not currently have long options corresponding to all short
687 * options; we should probably pick appropriate option names for them.
688 *
689 * However, the short options where the number of times the option is
690 * specified matters, such as -v and -d and -t, should probably not
691 * just map to a long option, as saying
692 *
693 * tcpdump --verbose --verbose
694 *
695 * doesn't make sense; it should be --verbosity={N} or something such
696 * as that.
697 *
698 * For long options with no corresponding short options, we define values
699 * outside the range of ASCII graphic characters, make that the last
700 * component of the entry for the long option, and have a case for that
701 * option in the switch statement.
702 */
703 #define OPTION_VERSION 128
704 #define OPTION_TSTAMP_PRECISION 129
705 #define OPTION_IMMEDIATE_MODE 130
706 #define OPTION_PRINT 131
707 #define OPTION_LIST_REMOTE_INTERFACES 132
708 #define OPTION_TSTAMP_MICRO 133
709 #define OPTION_TSTAMP_NANO 134
710 #define OPTION_FP_TYPE 135
711 #define OPTION_COUNT 136
712
713 static const struct option longopts[] = {
714 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
715 { "buffer-size", required_argument, NULL, 'B' },
716 #endif
717 { "list-interfaces", no_argument, NULL, 'D' },
718 #ifdef HAVE_PCAP_FINDALLDEVS_EX
719 { "list-remote-interfaces", required_argument, NULL, OPTION_LIST_REMOTE_INTERFACES },
720 #endif
721 { "help", no_argument, NULL, 'h' },
722 { "interface", required_argument, NULL, 'i' },
723 #ifdef HAVE_PCAP_CREATE
724 { "monitor-mode", no_argument, NULL, 'I' },
725 #endif
726 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
727 { "time-stamp-type", required_argument, NULL, 'j' },
728 { "list-time-stamp-types", no_argument, NULL, 'J' },
729 #endif
730 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
731 { "micro", no_argument, NULL, OPTION_TSTAMP_MICRO},
732 { "nano", no_argument, NULL, OPTION_TSTAMP_NANO},
733 { "time-stamp-precision", required_argument, NULL, OPTION_TSTAMP_PRECISION},
734 #endif
735 { "dont-verify-checksums", no_argument, NULL, 'K' },
736 { "list-data-link-types", no_argument, NULL, 'L' },
737 { "no-optimize", no_argument, NULL, 'O' },
738 { "no-promiscuous-mode", no_argument, NULL, 'p' },
739 #ifdef HAVE_PCAP_SETDIRECTION
740 { "direction", required_argument, NULL, 'Q' },
741 #endif
742 { "snapshot-length", required_argument, NULL, 's' },
743 { "absolute-tcp-sequence-numbers", no_argument, NULL, 'S' },
744 #ifdef HAVE_PCAP_DUMP_FLUSH
745 { "packet-buffered", no_argument, NULL, 'U' },
746 #endif
747 { "linktype", required_argument, NULL, 'y' },
748 #ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
749 { "immediate-mode", no_argument, NULL, OPTION_IMMEDIATE_MODE },
750 #endif
751 #ifdef HAVE_PCAP_SET_PARSER_DEBUG
752 { "debug-filter-parser", no_argument, NULL, 'Y' },
753 #endif
754 { "relinquish-privileges", required_argument, NULL, 'Z' },
755 { "count", no_argument, NULL, OPTION_COUNT },
756 { "fp-type", no_argument, NULL, OPTION_FP_TYPE },
757 { "number", no_argument, NULL, '#' },
758 { "print", no_argument, NULL, OPTION_PRINT },
759 { "version", no_argument, NULL, OPTION_VERSION },
760 { NULL, 0, NULL, 0 }
761 };
762
763 #ifdef HAVE_PCAP_FINDALLDEVS_EX
764 #define LIST_REMOTE_INTERFACES_USAGE "[ --list-remote-interfaces remote-source ]"
765 #else
766 #define LIST_REMOTE_INTERFACES_USAGE
767 #endif
768
769 #ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
770 #define IMMEDIATE_MODE_USAGE " [ --immediate-mode ]"
771 #else
772 #define IMMEDIATE_MODE_USAGE ""
773 #endif
774
775 #ifndef _WIN32
776 /* Drop root privileges and chroot if necessary */
777 static void
droproot(const char * username,const char * chroot_dir)778 droproot(const char *username, const char *chroot_dir)
779 {
780 struct passwd *pw = NULL;
781
782 if (chroot_dir && !username)
783 error("Chroot without dropping root is insecure");
784
785 pw = getpwnam(username);
786 if (pw) {
787 if (chroot_dir) {
788 if (chroot(chroot_dir) != 0 || chdir ("/") != 0)
789 error("Couldn't chroot/chdir to '%.64s': %s",
790 chroot_dir, pcap_strerror(errno));
791 }
792 #ifdef HAVE_LIBCAP_NG
793 {
794 int ret = capng_change_id(pw->pw_uid, pw->pw_gid, CAPNG_NO_FLAG);
795 if (ret < 0)
796 error("capng_change_id(): return %d\n", ret);
797 else
798 fprintf(stderr, "dropped privs to %s\n", username);
799 }
800 #else
801 if (initgroups(pw->pw_name, pw->pw_gid) != 0 ||
802 setgid(pw->pw_gid) != 0 || setuid(pw->pw_uid) != 0)
803 error("Couldn't change to '%.32s' uid=%lu gid=%lu: %s",
804 username,
805 (unsigned long)pw->pw_uid,
806 (unsigned long)pw->pw_gid,
807 pcap_strerror(errno));
808 else {
809 fprintf(stderr, "dropped privs to %s\n", username);
810 }
811 #endif /* HAVE_LIBCAP_NG */
812 } else
813 error("Couldn't find user '%.32s'", username);
814 #ifdef HAVE_LIBCAP_NG
815 /* We don't need CAP_SETUID, CAP_SETGID and CAP_SYS_CHROOT any more. */
816 DIAG_OFF_ASSIGN_ENUM
817 capng_updatev(
818 CAPNG_DROP,
819 CAPNG_EFFECTIVE | CAPNG_PERMITTED,
820 CAP_SETUID,
821 CAP_SETGID,
822 CAP_SYS_CHROOT,
823 -1);
824 DIAG_ON_ASSIGN_ENUM
825 capng_apply(CAPNG_SELECT_BOTH);
826 #endif /* HAVE_LIBCAP_NG */
827
828 }
829 #endif /* _WIN32 */
830
831 static int
getWflagChars(int x)832 getWflagChars(int x)
833 {
834 int c = 0;
835
836 x -= 1;
837 while (x > 0) {
838 c += 1;
839 x /= 10;
840 }
841
842 return c;
843 }
844
845
846 static void
MakeFilename(char * buffer,char * orig_name,int cnt,int max_chars)847 MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
848 {
849 char *filename = malloc(PATH_MAX + 1);
850 if (filename == NULL)
851 error("%s: malloc", __func__);
852 if (strlen(orig_name) == 0)
853 error("an empty string is not a valid file name");
854
855 /* Process with strftime if Gflag is set. */
856 if (Gflag != 0) {
857 struct tm *local_tm;
858
859 /* Convert Gflag_time to a usable format */
860 if ((local_tm = localtime(&Gflag_time)) == NULL) {
861 error("%s: localtime", __func__);
862 }
863
864 /* There's no good way to detect an error in strftime since a return
865 * value of 0 isn't necessarily failure; if orig_name is an empty
866 * string, the formatted string will be empty.
867 *
868 * However, the C90 standard says that, if there *is* a
869 * buffer overflow, the content of the buffer is undefined,
870 * so we must check for a buffer overflow.
871 *
872 * So we check above for an empty orig_name, and only call
873 * strftime() if it's non-empty, in which case the return
874 * value will only be 0 if the formatted date doesn't fit
875 * in the buffer.
876 *
877 * (We check above because, even if we don't use -G, we
878 * want a better error message than "tcpdump: : No such
879 * file or directory" for this case.)
880 */
881 if (strftime(filename, PATH_MAX, orig_name, local_tm) == 0) {
882 error("%s: strftime", __func__);
883 }
884 } else {
885 strncpy(filename, orig_name, PATH_MAX);
886 }
887
888 if (cnt == 0 && max_chars == 0)
889 strncpy(buffer, filename, PATH_MAX + 1);
890 else
891 if (snprintf(buffer, PATH_MAX + 1, "%s%0*d", filename, max_chars, cnt) > PATH_MAX)
892 /* Report an error if the filename is too large */
893 error("too many output files or filename is too long (> %d)", PATH_MAX);
894 free(filename);
895 }
896
897 static char *
get_next_file(FILE * VFile,char * ptr)898 get_next_file(FILE *VFile, char *ptr)
899 {
900 char *ret;
901 size_t len;
902
903 ret = fgets(ptr, PATH_MAX, VFile);
904 if (!ret)
905 return NULL;
906
907 len = strlen (ptr);
908 if (len > 0 && ptr[len - 1] == '\n')
909 ptr[len - 1] = '\0';
910
911 return ret;
912 }
913
914 #ifdef HAVE_CASPER
915 static cap_channel_t *
capdns_setup(void)916 capdns_setup(void)
917 {
918 cap_channel_t *capcas, *capdnsloc;
919 const char *types[1];
920 int families[2];
921
922 capcas = cap_init();
923 if (capcas == NULL)
924 error("unable to create casper process");
925 capdnsloc = cap_service_open(capcas, "system.dns");
926 /* Casper capability no longer needed. */
927 cap_close(capcas);
928 if (capdnsloc == NULL)
929 error("unable to open system.dns service");
930 /* Limit system.dns to reverse DNS lookups. */
931 types[0] = "ADDR2NAME";
932 if (cap_dns_type_limit(capdnsloc, types, 1) < 0)
933 error("unable to limit access to system.dns service");
934 families[0] = AF_INET;
935 families[1] = AF_INET6;
936 if (cap_dns_family_limit(capdnsloc, families, 2) < 0)
937 error("unable to limit access to system.dns service");
938
939 return (capdnsloc);
940 }
941 #endif /* HAVE_CASPER */
942
943 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
944 static int
tstamp_precision_from_string(const char * precision)945 tstamp_precision_from_string(const char *precision)
946 {
947 if (strncmp(precision, "nano", strlen("nano")) == 0)
948 return PCAP_TSTAMP_PRECISION_NANO;
949
950 if (strncmp(precision, "micro", strlen("micro")) == 0)
951 return PCAP_TSTAMP_PRECISION_MICRO;
952
953 return -EINVAL;
954 }
955
956 static const char *
tstamp_precision_to_string(int precision)957 tstamp_precision_to_string(int precision)
958 {
959 switch (precision) {
960
961 case PCAP_TSTAMP_PRECISION_MICRO:
962 return "micro";
963
964 case PCAP_TSTAMP_PRECISION_NANO:
965 return "nano";
966
967 default:
968 return "unknown";
969 }
970 }
971 #endif
972
973 #ifdef HAVE_CAPSICUM
974 /*
975 * Ensure that, on a dump file's descriptor, we have all the rights
976 * necessary to make the standard I/O library work with an fdopen()ed
977 * FILE * from that descriptor.
978 *
979 * A long time ago in a galaxy far, far away, AT&T decided that, instead
980 * of providing separate APIs for getting and setting the FD_ flags on a
981 * descriptor, getting and setting the O_ flags on a descriptor, and
982 * locking files, they'd throw them all into a kitchen-sink fcntl() call
983 * along the lines of ioctl(), the fact that ioctl() operations are
984 * largely specific to particular character devices but fcntl() operations
985 * are either generic to all descriptors or generic to all descriptors for
986 * regular files nonwithstanding.
987 *
988 * The Capsicum people decided that fine-grained control of descriptor
989 * operations was required, so that you need to grant permission for
990 * reading, writing, seeking, and fcntl-ing. The latter, courtesy of
991 * AT&T's decision, means that "fcntl-ing" isn't a thing, but a motley
992 * collection of things, so there are *individual* fcntls for which
993 * permission needs to be granted.
994 *
995 * The FreeBSD standard I/O people implemented some optimizations that
996 * requires that the standard I/O routines be able to determine whether
997 * the descriptor for the FILE * is open append-only or not; as that
998 * descriptor could have come from an open() rather than an fopen(),
999 * that requires that it be able to do an F_GETFL fcntl() to read
1000 * the O_ flags.
1001 *
1002 * Tcpdump uses ftell() to determine how much data has been written
1003 * to a file in order to, when used with -C, determine when it's time
1004 * to rotate capture files. ftell() therefore needs to do an lseek()
1005 * to find out the file offset and must, thanks to the aforementioned
1006 * optimization, also know whether the descriptor is open append-only
1007 * or not.
1008 *
1009 * The net result of all the above is that we need to grant CAP_SEEK,
1010 * CAP_WRITE, and CAP_FCNTL with the CAP_FCNTL_GETFL subcapability.
1011 *
1012 * Perhaps this is the universe's way of saying that either
1013 *
1014 * 1) there needs to be an fopenat() call and a pcap_dump_openat() call
1015 * using it, so that Capsicum-capable tcpdump wouldn't need to do
1016 * an fdopen()
1017 *
1018 * or
1019 *
1020 * 2) there needs to be a cap_fdopen() call in the FreeBSD standard
1021 * I/O library that knows what rights are needed by the standard
1022 * I/O library, based on the open mode, and assigns them, perhaps
1023 * with an additional argument indicating, for example, whether
1024 * seeking should be allowed, so that tcpdump doesn't need to know
1025 * what the standard I/O library happens to require this week.
1026 */
1027 static void
set_dumper_capsicum_rights(pcap_dumper_t * p)1028 set_dumper_capsicum_rights(pcap_dumper_t *p)
1029 {
1030 int fd = fileno(pcap_dump_file(p));
1031 cap_rights_t rights;
1032
1033 cap_rights_init(&rights, CAP_SEEK, CAP_WRITE, CAP_FCNTL);
1034 if (cap_rights_limit(fd, &rights) < 0 && errno != ENOSYS) {
1035 error("unable to limit dump descriptor");
1036 }
1037 if (cap_fcntls_limit(fd, CAP_FCNTL_GETFL) < 0 && errno != ENOSYS) {
1038 error("unable to limit dump descriptor fcntls");
1039 }
1040 }
1041 #endif
1042
1043 /*
1044 * Copy arg vector into a new buffer, concatenating arguments with spaces.
1045 */
1046 static char *
copy_argv(char ** argv)1047 copy_argv(char **argv)
1048 {
1049 char **p;
1050 size_t len = 0;
1051 char *buf;
1052 char *src, *dst;
1053
1054 p = argv;
1055 if (*p == NULL)
1056 return 0;
1057
1058 while (*p)
1059 len += strlen(*p++) + 1;
1060
1061 buf = (char *)malloc(len);
1062 if (buf == NULL)
1063 error("%s: malloc", __func__);
1064
1065 p = argv;
1066 dst = buf;
1067 while ((src = *p++) != NULL) {
1068 while ((*dst++ = *src++) != '\0')
1069 ;
1070 dst[-1] = ' ';
1071 }
1072 dst[-1] = '\0';
1073
1074 return buf;
1075 }
1076
1077 /*
1078 * On Windows, we need to open the file in binary mode, so that
1079 * we get all the bytes specified by the size we get from "fstat()".
1080 * On UNIX, that's not necessary. O_BINARY is defined on Windows;
1081 * we define it as 0 if it's not defined, so it does nothing.
1082 */
1083 #ifndef O_BINARY
1084 #define O_BINARY 0
1085 #endif
1086
1087 static char *
read_infile(char * fname)1088 read_infile(char *fname)
1089 {
1090 int i, fd;
1091 ssize_t cc;
1092 char *cp;
1093 our_statb buf;
1094
1095 fd = open(fname, O_RDONLY|O_BINARY);
1096 if (fd < 0)
1097 error("can't open %s: %s", fname, pcap_strerror(errno));
1098
1099 if (our_fstat(fd, &buf) < 0)
1100 error("can't stat %s: %s", fname, pcap_strerror(errno));
1101
1102 /*
1103 * Reject files whose size doesn't fit into an int; a filter
1104 * *that* large will probably be too big.
1105 */
1106 if (buf.st_size > INT_MAX)
1107 error("%s is too large", fname);
1108
1109 cp = malloc((u_int)buf.st_size + 1);
1110 if (cp == NULL)
1111 error("malloc(%d) for %s: %s", (u_int)buf.st_size + 1,
1112 fname, pcap_strerror(errno));
1113 cc = read(fd, cp, (u_int)buf.st_size);
1114 if (cc < 0)
1115 error("read %s: %s", fname, pcap_strerror(errno));
1116 if (cc != buf.st_size)
1117 error("short read %s (%d != %d)", fname, (int) cc,
1118 (int)buf.st_size);
1119
1120 close(fd);
1121 /* replace "# comment" with spaces */
1122 for (i = 0; i < cc; i++) {
1123 if (cp[i] == '#')
1124 while (i < cc && cp[i] != '\n')
1125 cp[i++] = ' ';
1126 }
1127 cp[cc] = '\0';
1128 return (cp);
1129 }
1130
1131 #ifdef HAVE_PCAP_FINDALLDEVS
1132 static long
parse_interface_number(const char * device)1133 parse_interface_number(const char *device)
1134 {
1135 const char *p;
1136 long devnum;
1137 char *end;
1138
1139 /*
1140 * Search for a colon, terminating any scheme at the beginning
1141 * of the device.
1142 */
1143 p = strchr(device, ':');
1144 if (p != NULL) {
1145 /*
1146 * We found it. Is it followed by "//"?
1147 */
1148 p++; /* skip the : */
1149 if (strncmp(p, "//", 2) == 0) {
1150 /*
1151 * Yes. Search for the next /, at the end of the
1152 * authority part of the URL.
1153 */
1154 p += 2; /* skip the // */
1155 p = strchr(p, '/');
1156 if (p != NULL) {
1157 /*
1158 * OK, past the / is the path.
1159 */
1160 device = p + 1;
1161 }
1162 }
1163 }
1164 devnum = strtol(device, &end, 10);
1165 if (device != end && *end == '\0') {
1166 /*
1167 * It's all-numeric, but is it a valid number?
1168 */
1169 if (devnum <= 0) {
1170 /*
1171 * No, it's not an ordinal.
1172 */
1173 error("Invalid adapter index");
1174 }
1175 return (devnum);
1176 } else {
1177 /*
1178 * It's not all-numeric; return -1, so our caller
1179 * knows that.
1180 */
1181 return (-1);
1182 }
1183 }
1184
1185 static char *
find_interface_by_number(const char * url _U_,long devnum)1186 find_interface_by_number(const char *url
1187 #ifndef HAVE_PCAP_FINDALLDEVS_EX
1188 _U_
1189 #endif
1190 , long devnum)
1191 {
1192 pcap_if_t *dev, *devlist;
1193 long i;
1194 char ebuf[PCAP_ERRBUF_SIZE];
1195 char *device;
1196 #ifdef HAVE_PCAP_FINDALLDEVS_EX
1197 const char *endp;
1198 char *host_url;
1199 #endif
1200 int status;
1201
1202 #ifdef HAVE_PCAP_FINDALLDEVS_EX
1203 /*
1204 * Search for a colon, terminating any scheme at the beginning
1205 * of the URL.
1206 */
1207 endp = strchr(url, ':');
1208 if (endp != NULL) {
1209 /*
1210 * We found it. Is it followed by "//"?
1211 */
1212 endp++; /* skip the : */
1213 if (strncmp(endp, "//", 2) == 0) {
1214 /*
1215 * Yes. Search for the next /, at the end of the
1216 * authority part of the URL.
1217 */
1218 endp += 2; /* skip the // */
1219 endp = strchr(endp, '/');
1220 } else
1221 endp = NULL;
1222 }
1223 if (endp != NULL) {
1224 /*
1225 * OK, everything from device to endp is a URL to hand
1226 * to pcap_findalldevs_ex().
1227 */
1228 endp++; /* Include the trailing / in the URL; pcap_findalldevs_ex() requires it */
1229 host_url = malloc(endp - url + 1);
1230 if (host_url == NULL && (endp - url + 1) > 0)
1231 error("Invalid allocation for host");
1232
1233 memcpy(host_url, url, endp - url);
1234 host_url[endp - url] = '\0';
1235 status = pcap_findalldevs_ex(host_url, NULL, &devlist, ebuf);
1236 free(host_url);
1237 } else
1238 #endif
1239 status = pcap_findalldevs(&devlist, ebuf);
1240 if (status < 0)
1241 error("%s", ebuf);
1242 /*
1243 * Look for the devnum-th entry in the list of devices (1-based).
1244 */
1245 for (i = 0, dev = devlist; i < devnum-1 && dev != NULL;
1246 i++, dev = dev->next)
1247 ;
1248 if (dev == NULL)
1249 error("Invalid adapter index");
1250 device = strdup(dev->name);
1251 pcap_freealldevs(devlist);
1252 return (device);
1253 }
1254 #endif
1255
1256 #ifdef HAVE_PCAP_OPEN
1257 /*
1258 * Prefixes for rpcap URLs.
1259 */
1260 static char rpcap_prefix[] = "rpcap://";
1261 static char rpcap_ssl_prefix[] = "rpcaps://";
1262 #endif
1263
1264 static pcap_t *
open_interface(const char * device,netdissect_options * ndo,char * ebuf)1265 open_interface(const char *device, netdissect_options *ndo, char *ebuf)
1266 {
1267 pcap_t *pc;
1268 #ifdef HAVE_PCAP_CREATE
1269 int status;
1270 char *cp;
1271 #endif
1272
1273 #ifdef HAVE_PCAP_OPEN
1274 /*
1275 * Is this an rpcap URL?
1276 */
1277 if (strncmp(device, rpcap_prefix, sizeof(rpcap_prefix) - 1) == 0 ||
1278 strncmp(device, rpcap_ssl_prefix, sizeof(rpcap_ssl_prefix) - 1) == 0) {
1279 /*
1280 * Yes. Open it with pcap_open().
1281 */
1282 *ebuf = '\0';
1283 pc = pcap_open(device, ndo->ndo_snaplen,
1284 pflag ? 0 : PCAP_OPENFLAG_PROMISCUOUS, timeout, NULL,
1285 ebuf);
1286 if (pc == NULL) {
1287 /*
1288 * If this failed with "No such device" or "The system
1289 * cannot find the device specified", that means
1290 * the interface doesn't exist; return NULL, so that
1291 * the caller can see whether the device name is
1292 * actually an interface index.
1293 */
1294 if (strstr(ebuf, "No such device") != NULL ||
1295 strstr(ebuf, "The system cannot find the device specified") != NULL)
1296 return (NULL);
1297 error("%s", ebuf);
1298 }
1299 if (*ebuf)
1300 warning("%s", ebuf);
1301 return (pc);
1302 }
1303 #endif /* HAVE_PCAP_OPEN */
1304
1305 #ifdef HAVE_PCAP_CREATE
1306 pc = pcap_create(device, ebuf);
1307 if (pc == NULL) {
1308 /*
1309 * If this failed with "No such device", that means
1310 * the interface doesn't exist; return NULL, so that
1311 * the caller can see whether the device name is
1312 * actually an interface index.
1313 */
1314 if (strstr(ebuf, "No such device") != NULL)
1315 return (NULL);
1316 error("%s", ebuf);
1317 }
1318 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
1319 if (Jflag)
1320 show_tstamp_types_and_exit(pc, device);
1321 #endif
1322 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
1323 status = pcap_set_tstamp_precision(pc, ndo->ndo_tstamp_precision);
1324 if (status != 0)
1325 error("%s: Can't set %ssecond time stamp precision: %s",
1326 device,
1327 tstamp_precision_to_string(ndo->ndo_tstamp_precision),
1328 pcap_statustostr(status));
1329 #endif
1330
1331 #ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
1332 if (immediate_mode) {
1333 status = pcap_set_immediate_mode(pc, 1);
1334 if (status != 0)
1335 error("%s: Can't set immediate mode: %s",
1336 device, pcap_statustostr(status));
1337 }
1338 #endif
1339 /*
1340 * Is this an interface that supports monitor mode?
1341 */
1342 if (pcap_can_set_rfmon(pc) == 1)
1343 supports_monitor_mode = 1;
1344 else
1345 supports_monitor_mode = 0;
1346 if (ndo->ndo_snaplen != 0) {
1347 /*
1348 * A snapshot length was explicitly specified;
1349 * use it.
1350 */
1351 status = pcap_set_snaplen(pc, ndo->ndo_snaplen);
1352 if (status != 0)
1353 error("%s: Can't set snapshot length: %s",
1354 device, pcap_statustostr(status));
1355 }
1356 status = pcap_set_promisc(pc, !pflag);
1357 if (status != 0)
1358 error("%s: Can't set promiscuous mode: %s",
1359 device, pcap_statustostr(status));
1360 if (Iflag) {
1361 status = pcap_set_rfmon(pc, 1);
1362 if (status != 0)
1363 error("%s: Can't set monitor mode: %s",
1364 device, pcap_statustostr(status));
1365 }
1366 status = pcap_set_timeout(pc, timeout);
1367 if (status != 0)
1368 error("%s: pcap_set_timeout failed: %s",
1369 device, pcap_statustostr(status));
1370 if (Bflag != 0) {
1371 status = pcap_set_buffer_size(pc, Bflag);
1372 if (status != 0)
1373 error("%s: Can't set buffer size: %s",
1374 device, pcap_statustostr(status));
1375 }
1376 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
1377 if (jflag != -1) {
1378 status = pcap_set_tstamp_type(pc, jflag);
1379 if (status < 0)
1380 error("%s: Can't set time stamp type: %s",
1381 device, pcap_statustostr(status));
1382 else if (status > 0)
1383 warning("When trying to set timestamp type '%s' on %s: %s",
1384 pcap_tstamp_type_val_to_name(jflag), device,
1385 pcap_statustostr(status));
1386 }
1387 #endif
1388 status = pcap_activate(pc);
1389 if (status < 0) {
1390 /*
1391 * pcap_activate() failed.
1392 */
1393 cp = pcap_geterr(pc);
1394 if (status == PCAP_ERROR)
1395 error("%s", cp);
1396 else if (status == PCAP_ERROR_NO_SUCH_DEVICE) {
1397 /*
1398 * Return an error for our caller to handle.
1399 */
1400 snprintf(ebuf, PCAP_ERRBUF_SIZE, "%s: %s\n(%s)",
1401 device, pcap_statustostr(status), cp);
1402 } else if (status == PCAP_ERROR_PERM_DENIED && *cp != '\0')
1403 error("%s: %s\n(%s)", device,
1404 pcap_statustostr(status), cp);
1405 #ifdef __FreeBSD__
1406 else if (status == PCAP_ERROR_RFMON_NOTSUP &&
1407 strncmp(device, "wlan", 4) == 0) {
1408 char parent[8], newdev[8];
1409 char sysctl[32];
1410 size_t s = sizeof(parent);
1411
1412 snprintf(sysctl, sizeof(sysctl),
1413 "net.wlan.%d.%%parent", atoi(device + 4));
1414 sysctlbyname(sysctl, parent, &s, NULL, 0);
1415 strlcpy(newdev, device, sizeof(newdev));
1416 /* Suggest a new wlan device. */
1417 /* FIXME: incrementing the index this way is not going to work well
1418 * when the index is 9 or greater but the only consequence in this
1419 * specific case would be an error message that looks a bit odd.
1420 */
1421 newdev[strlen(newdev)-1]++;
1422 error("%s is not a monitor mode VAP\n"
1423 "To create a new monitor mode VAP use:\n"
1424 " ifconfig %s create wlandev %s wlanmode monitor\n"
1425 "and use %s as the tcpdump interface",
1426 device, newdev, parent, newdev);
1427 }
1428 #endif
1429 else
1430 error("%s: %s", device,
1431 pcap_statustostr(status));
1432 pcap_close(pc);
1433 return (NULL);
1434 } else if (status > 0) {
1435 /*
1436 * pcap_activate() succeeded, but it's warning us
1437 * of a problem it had.
1438 */
1439 cp = pcap_geterr(pc);
1440 if (status == PCAP_WARNING)
1441 warning("%s", cp);
1442 else if (status == PCAP_WARNING_PROMISC_NOTSUP &&
1443 *cp != '\0')
1444 warning("%s: %s\n(%s)", device,
1445 pcap_statustostr(status), cp);
1446 else
1447 warning("%s: %s", device,
1448 pcap_statustostr(status));
1449 }
1450 #ifdef HAVE_PCAP_SETDIRECTION
1451 if (Qflag != -1) {
1452 status = pcap_setdirection(pc, Qflag);
1453 if (status != 0)
1454 error("%s: pcap_setdirection() failed: %s",
1455 device, pcap_geterr(pc));
1456 }
1457 #endif /* HAVE_PCAP_SETDIRECTION */
1458 #else /* HAVE_PCAP_CREATE */
1459 *ebuf = '\0';
1460 /*
1461 * If no snapshot length was specified, or a length of 0 was
1462 * specified, default to 256KB.
1463 */
1464 if (ndo->ndo_snaplen == 0)
1465 ndo->ndo_snaplen = MAXIMUM_SNAPLEN;
1466 pc = pcap_open_live(device, ndo->ndo_snaplen, !pflag, timeout, ebuf);
1467 if (pc == NULL) {
1468 /*
1469 * If this failed with "No such device", that means
1470 * the interface doesn't exist; return NULL, so that
1471 * the caller can see whether the device name is
1472 * actually an interface index.
1473 */
1474 if (strstr(ebuf, "No such device") != NULL)
1475 return (NULL);
1476 error("%s", ebuf);
1477 }
1478 if (*ebuf)
1479 warning("%s", ebuf);
1480 #endif /* HAVE_PCAP_CREATE */
1481
1482 return (pc);
1483 }
1484
1485 int
main(int argc,char ** argv)1486 main(int argc, char **argv)
1487 {
1488 int cnt, op, i;
1489 bpf_u_int32 localnet = 0, netmask = 0;
1490 char *cp, *infile, *cmdbuf, *device, *RFileName, *VFileName, *WFileName;
1491 char *endp;
1492 pcap_handler callback;
1493 int dlt;
1494 const char *dlt_name;
1495 struct bpf_program fcode;
1496 #ifndef _WIN32
1497 void (*oldhandler)(int);
1498 #endif
1499 struct dump_info dumpinfo;
1500 u_char *pcap_userdata;
1501 char ebuf[PCAP_ERRBUF_SIZE];
1502 char VFileLine[PATH_MAX + 1];
1503 const char *username = NULL;
1504 #ifndef _WIN32
1505 const char *chroot_dir = NULL;
1506 #endif
1507 char *ret = NULL;
1508 char *end;
1509 #ifdef HAVE_PCAP_FINDALLDEVS
1510 pcap_if_t *devlist;
1511 long devnum;
1512 #endif
1513 int status;
1514 FILE *VFile;
1515 #ifdef HAVE_CAPSICUM
1516 cap_rights_t rights;
1517 int cansandbox;
1518 #endif /* HAVE_CAPSICUM */
1519 int Oflag = 1; /* run filter code optimizer */
1520 int yflag_dlt = -1;
1521 const char *yflag_dlt_name = NULL;
1522 int print = 0;
1523
1524 netdissect_options Ndo;
1525 netdissect_options *ndo = &Ndo;
1526
1527 /*
1528 * Initialize the netdissect code.
1529 */
1530 if (nd_init(ebuf, sizeof(ebuf)) == -1)
1531 error("%s", ebuf);
1532
1533 memset(ndo, 0, sizeof(*ndo));
1534 ndo_set_function_pointers(ndo);
1535
1536 cnt = -1;
1537 device = NULL;
1538 infile = NULL;
1539 RFileName = NULL;
1540 VFileName = NULL;
1541 VFile = NULL;
1542 WFileName = NULL;
1543 dlt = -1;
1544 if ((cp = strrchr(argv[0], PATH_SEPARATOR)) != NULL)
1545 ndo->program_name = program_name = cp + 1;
1546 else
1547 ndo->program_name = program_name = argv[0];
1548
1549 #if defined(HAVE_PCAP_WSOCKINIT)
1550 if (pcap_wsockinit() != 0)
1551 error("Attempting to initialize Winsock failed");
1552 #elif defined(HAVE_WSOCKINIT)
1553 if (wsockinit() != 0)
1554 error("Attempting to initialize Winsock failed");
1555 #endif
1556
1557 /*
1558 * On platforms where the CPU doesn't support unaligned loads,
1559 * force unaligned accesses to abort with SIGBUS, rather than
1560 * being fixed up (slowly) by the OS kernel; on those platforms,
1561 * misaligned accesses are bugs, and we want tcpdump to crash so
1562 * that the bugs are reported.
1563 */
1564 if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
1565 error("%s", ebuf);
1566
1567 tzset();
1568
1569 while (
1570 (op = getopt_long(argc, argv, SHORTOPTS, longopts, NULL)) != -1)
1571 switch (op) {
1572
1573 case 'a':
1574 /* compatibility for old -a */
1575 break;
1576
1577 case 'A':
1578 ++ndo->ndo_Aflag;
1579 break;
1580
1581 case 'b':
1582 ++ndo->ndo_bflag;
1583 break;
1584
1585 #if defined(HAVE_PCAP_CREATE) || defined(_WIN32)
1586 case 'B':
1587 Bflag = atoi(optarg)*1024;
1588 if (Bflag <= 0)
1589 error("invalid packet buffer size %s", optarg);
1590 break;
1591 #endif /* defined(HAVE_PCAP_CREATE) || defined(_WIN32) */
1592
1593 case 'c':
1594 cnt = atoi(optarg);
1595 if (cnt <= 0)
1596 error("invalid packet count %s", optarg);
1597 break;
1598
1599 case 'C':
1600 errno = 0;
1601 #ifdef HAVE_PCAP_DUMP_FTELL64
1602 Cflag = strtoint64_t(optarg, &endp, 10);
1603 #else
1604 Cflag = strtol(optarg, &endp, 10);
1605 #endif
1606 if (endp == optarg || *endp != '\0' || errno != 0
1607 || Cflag <= 0)
1608 error("invalid file size %s", optarg);
1609 /*
1610 * Will multiplying it by 1000000 overflow?
1611 */
1612 #ifdef HAVE_PCAP_DUMP_FTELL64
1613 if (Cflag > INT64_T_CONSTANT(0x7fffffffffffffff) / 1000000)
1614 #else
1615 if (Cflag > LONG_MAX / 1000000)
1616 #endif
1617 error("file size %s is too large", optarg);
1618 Cflag *= 1000000;
1619 break;
1620
1621 case 'd':
1622 ++dflag;
1623 break;
1624
1625 #ifdef HAVE_PCAP_FINDALLDEVS
1626 case 'D':
1627 Dflag++;
1628 break;
1629 #endif
1630
1631 #ifdef HAVE_PCAP_FINDALLDEVS_EX
1632 case OPTION_LIST_REMOTE_INTERFACES:
1633 remote_interfaces_source = optarg;
1634 break;
1635 #endif
1636
1637 case 'L':
1638 Lflag++;
1639 break;
1640
1641 case 'e':
1642 ++ndo->ndo_eflag;
1643 break;
1644
1645 case 'E':
1646 #ifndef HAVE_LIBCRYPTO
1647 warning("crypto code not compiled in");
1648 #endif
1649 ndo->ndo_espsecret = optarg;
1650 break;
1651
1652 case 'f':
1653 ++ndo->ndo_fflag;
1654 break;
1655
1656 case 'F':
1657 infile = optarg;
1658 break;
1659
1660 case 'G':
1661 Gflag = atoi(optarg);
1662 if (Gflag < 0)
1663 error("invalid number of seconds %s", optarg);
1664
1665 /* We will create one file initially. */
1666 Gflag_count = 0;
1667
1668 /* Grab the current time for rotation use. */
1669 if ((Gflag_time = time(NULL)) == (time_t)-1) {
1670 error("%s: can't get current time: %s",
1671 __func__, pcap_strerror(errno));
1672 }
1673 break;
1674
1675 case 'h':
1676 print_usage(stdout);
1677 exit_tcpdump(S_SUCCESS);
1678 break;
1679
1680 case 'H':
1681 ++ndo->ndo_Hflag;
1682 break;
1683
1684 case 'i':
1685 device = optarg;
1686 break;
1687
1688 #ifdef HAVE_PCAP_CREATE
1689 case 'I':
1690 ++Iflag;
1691 break;
1692 #endif /* HAVE_PCAP_CREATE */
1693
1694 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
1695 case 'j':
1696 jflag = pcap_tstamp_type_name_to_val(optarg);
1697 if (jflag < 0)
1698 error("invalid time stamp type %s", optarg);
1699 break;
1700
1701 case 'J':
1702 Jflag++;
1703 break;
1704 #endif
1705
1706 case 'l':
1707 #ifdef _WIN32
1708 /*
1709 * _IOLBF is the same as _IOFBF in Microsoft's C
1710 * libraries; the only alternative they offer
1711 * is _IONBF.
1712 *
1713 * XXX - this should really be checking for MSVC++,
1714 * not _WIN32, if, for example, MinGW has its own
1715 * C library that is more UNIX-compatible.
1716 */
1717 setvbuf(stdout, NULL, _IONBF, 0);
1718 #else /* _WIN32 */
1719 #ifdef HAVE_SETLINEBUF
1720 setlinebuf(stdout);
1721 #else
1722 setvbuf(stdout, NULL, _IOLBF, 0);
1723 #endif
1724 #endif /* _WIN32 */
1725 lflag = 1;
1726 break;
1727
1728 case 'K':
1729 ++ndo->ndo_Kflag;
1730 break;
1731
1732 case 'm':
1733 if (nd_have_smi_support()) {
1734 if (nd_load_smi_module(optarg, ebuf, sizeof(ebuf)) == -1)
1735 error("%s", ebuf);
1736 } else {
1737 (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
1738 program_name, optarg);
1739 (void)fprintf(stderr, "(no libsmi support)\n");
1740 }
1741 break;
1742
1743 case 'M':
1744 /* TCP-MD5 shared secret */
1745 #ifndef HAVE_LIBCRYPTO
1746 warning("crypto code not compiled in");
1747 #endif
1748 ndo->ndo_sigsecret = optarg;
1749 break;
1750
1751 case 'n':
1752 ++ndo->ndo_nflag;
1753 break;
1754
1755 case 'N':
1756 ++ndo->ndo_Nflag;
1757 break;
1758
1759 case 'O':
1760 Oflag = 0;
1761 break;
1762
1763 case 'p':
1764 ++pflag;
1765 break;
1766
1767 case 'q':
1768 ++ndo->ndo_qflag;
1769 ++ndo->ndo_suppress_default_print;
1770 break;
1771
1772 #ifdef HAVE_PCAP_SETDIRECTION
1773 case 'Q':
1774 if (ascii_strcasecmp(optarg, "in") == 0)
1775 Qflag = PCAP_D_IN;
1776 else if (ascii_strcasecmp(optarg, "out") == 0)
1777 Qflag = PCAP_D_OUT;
1778 else if (ascii_strcasecmp(optarg, "inout") == 0)
1779 Qflag = PCAP_D_INOUT;
1780 else
1781 error("unknown capture direction `%s'", optarg);
1782 break;
1783 #endif /* HAVE_PCAP_SETDIRECTION */
1784
1785 case 'r':
1786 RFileName = optarg;
1787 break;
1788
1789 case 's':
1790 ndo->ndo_snaplen = (int)strtol(optarg, &end, 0);
1791 if (optarg == end || *end != '\0'
1792 || ndo->ndo_snaplen < 0 || ndo->ndo_snaplen > MAXIMUM_SNAPLEN)
1793 error("invalid snaplen %s (must be >= 0 and <= %d)",
1794 optarg, MAXIMUM_SNAPLEN);
1795 break;
1796
1797 case 'S':
1798 ++ndo->ndo_Sflag;
1799 break;
1800
1801 case 't':
1802 ++ndo->ndo_tflag;
1803 break;
1804
1805 case 'T':
1806 if (ascii_strcasecmp(optarg, "vat") == 0)
1807 ndo->ndo_packettype = PT_VAT;
1808 else if (ascii_strcasecmp(optarg, "wb") == 0)
1809 ndo->ndo_packettype = PT_WB;
1810 else if (ascii_strcasecmp(optarg, "rpc") == 0)
1811 ndo->ndo_packettype = PT_RPC;
1812 else if (ascii_strcasecmp(optarg, "rtp") == 0)
1813 ndo->ndo_packettype = PT_RTP;
1814 else if (ascii_strcasecmp(optarg, "rtcp") == 0)
1815 ndo->ndo_packettype = PT_RTCP;
1816 else if (ascii_strcasecmp(optarg, "snmp") == 0)
1817 ndo->ndo_packettype = PT_SNMP;
1818 else if (ascii_strcasecmp(optarg, "cnfp") == 0)
1819 ndo->ndo_packettype = PT_CNFP;
1820 else if (ascii_strcasecmp(optarg, "tftp") == 0)
1821 ndo->ndo_packettype = PT_TFTP;
1822 else if (ascii_strcasecmp(optarg, "aodv") == 0)
1823 ndo->ndo_packettype = PT_AODV;
1824 else if (ascii_strcasecmp(optarg, "carp") == 0)
1825 ndo->ndo_packettype = PT_CARP;
1826 else if (ascii_strcasecmp(optarg, "radius") == 0)
1827 ndo->ndo_packettype = PT_RADIUS;
1828 else if (ascii_strcasecmp(optarg, "zmtp1") == 0)
1829 ndo->ndo_packettype = PT_ZMTP1;
1830 else if (ascii_strcasecmp(optarg, "vxlan") == 0)
1831 ndo->ndo_packettype = PT_VXLAN;
1832 else if (ascii_strcasecmp(optarg, "pgm") == 0)
1833 ndo->ndo_packettype = PT_PGM;
1834 else if (ascii_strcasecmp(optarg, "pgm_zmtp1") == 0)
1835 ndo->ndo_packettype = PT_PGM_ZMTP1;
1836 else if (ascii_strcasecmp(optarg, "lmp") == 0)
1837 ndo->ndo_packettype = PT_LMP;
1838 else if (ascii_strcasecmp(optarg, "resp") == 0)
1839 ndo->ndo_packettype = PT_RESP;
1840 else if (ascii_strcasecmp(optarg, "ptp") == 0)
1841 ndo->ndo_packettype = PT_PTP;
1842 else if (ascii_strcasecmp(optarg, "someip") == 0)
1843 ndo->ndo_packettype = PT_SOMEIP;
1844 else if (ascii_strcasecmp(optarg, "domain") == 0)
1845 ndo->ndo_packettype = PT_DOMAIN;
1846 else
1847 error("unknown packet type `%s'", optarg);
1848 break;
1849
1850 case 'u':
1851 ++ndo->ndo_uflag;
1852 break;
1853
1854 #ifdef HAVE_PCAP_DUMP_FLUSH
1855 case 'U':
1856 ++Uflag;
1857 break;
1858 #endif
1859
1860 case 'v':
1861 ++ndo->ndo_vflag;
1862 break;
1863
1864 case 'V':
1865 VFileName = optarg;
1866 break;
1867
1868 case 'w':
1869 WFileName = optarg;
1870 break;
1871
1872 case 'W':
1873 Wflag = atoi(optarg);
1874 if (Wflag <= 0)
1875 error("invalid number of output files %s", optarg);
1876 WflagChars = getWflagChars(Wflag);
1877 break;
1878
1879 case 'x':
1880 ++ndo->ndo_xflag;
1881 ++ndo->ndo_suppress_default_print;
1882 break;
1883
1884 case 'X':
1885 ++ndo->ndo_Xflag;
1886 ++ndo->ndo_suppress_default_print;
1887 break;
1888
1889 case 'y':
1890 yflag_dlt_name = optarg;
1891 yflag_dlt =
1892 pcap_datalink_name_to_val(yflag_dlt_name);
1893 if (yflag_dlt < 0)
1894 error("invalid data link type %s", yflag_dlt_name);
1895 break;
1896
1897 #ifdef HAVE_PCAP_SET_PARSER_DEBUG
1898 case 'Y':
1899 {
1900 /* Undocumented flag */
1901 pcap_set_parser_debug(1);
1902 }
1903 break;
1904 #endif
1905 case 'z':
1906 zflag = optarg;
1907 break;
1908
1909 case 'Z':
1910 username = optarg;
1911 break;
1912
1913 case '#':
1914 ndo->ndo_packet_number = 1;
1915 break;
1916
1917 case OPTION_VERSION:
1918 print_version(stdout);
1919 exit_tcpdump(S_SUCCESS);
1920 break;
1921
1922 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
1923 case OPTION_TSTAMP_PRECISION:
1924 ndo->ndo_tstamp_precision = tstamp_precision_from_string(optarg);
1925 if (ndo->ndo_tstamp_precision < 0)
1926 error("unsupported time stamp precision");
1927 break;
1928 #endif
1929
1930 #ifdef HAVE_PCAP_SET_IMMEDIATE_MODE
1931 case OPTION_IMMEDIATE_MODE:
1932 immediate_mode = 1;
1933 break;
1934 #endif
1935
1936 case OPTION_PRINT:
1937 print = 1;
1938 break;
1939
1940 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
1941 case OPTION_TSTAMP_MICRO:
1942 ndo->ndo_tstamp_precision = PCAP_TSTAMP_PRECISION_MICRO;
1943 break;
1944
1945 case OPTION_TSTAMP_NANO:
1946 ndo->ndo_tstamp_precision = PCAP_TSTAMP_PRECISION_NANO;
1947 break;
1948 #endif
1949
1950 case OPTION_FP_TYPE:
1951 /*
1952 * Print out the type of floating-point arithmetic
1953 * we're doing; it's probably IEEE, unless somebody
1954 * tries to run this on a VAX, but the precision
1955 * may differ (e.g., it might be 32-bit, 64-bit,
1956 * or 80-bit).
1957 */
1958 float_type_check(0x4e93312d);
1959 return 0;
1960
1961 case OPTION_COUNT:
1962 count_mode = 1;
1963 break;
1964
1965 default:
1966 print_usage(stderr);
1967 exit_tcpdump(S_ERR_HOST_PROGRAM);
1968 /* NOTREACHED */
1969 }
1970
1971 #ifdef HAVE_PCAP_FINDALLDEVS
1972 if (Dflag)
1973 show_devices_and_exit();
1974 #endif
1975 #ifdef HAVE_PCAP_FINDALLDEVS_EX
1976 if (remote_interfaces_source != NULL)
1977 show_remote_devices_and_exit();
1978 #endif
1979
1980 #if defined(DLT_LINUX_SLL2) && defined(HAVE_PCAP_SET_DATALINK)
1981 /* Set default linktype DLT_LINUX_SLL2 when capturing on the "any" device */
1982 if (device != NULL &&
1983 strncmp (device, "any", strlen("any")) == 0
1984 && yflag_dlt == -1)
1985 yflag_dlt = DLT_LINUX_SLL2;
1986 #endif
1987
1988 switch (ndo->ndo_tflag) {
1989
1990 case 0: /* Default */
1991 case 1: /* No time stamp */
1992 case 2: /* Unix timeval style */
1993 case 3: /* Microseconds/nanoseconds since previous packet */
1994 case 4: /* Date + Default */
1995 case 5: /* Microseconds/nanoseconds since first packet */
1996 break;
1997
1998 default: /* Not supported */
1999 error("only -t, -tt, -ttt, -tttt and -ttttt are supported");
2000 break;
2001 }
2002
2003 if (ndo->ndo_fflag != 0 && (VFileName != NULL || RFileName != NULL))
2004 error("-f can not be used with -V or -r");
2005
2006 if (VFileName != NULL && RFileName != NULL)
2007 error("-V and -r are mutually exclusive.");
2008
2009 /*
2010 * If we're printing dissected packets to the standard output,
2011 * and either the standard output is a terminal or we're doing
2012 * "line" buffering, set the capture timeout to .1 second rather
2013 * than 1 second, as the user's probably expecting to see packets
2014 * pop up immediately shortly after they arrive.
2015 *
2016 * XXX - would there be some value appropriate for all cases,
2017 * based on, say, the buffer size and packet input rate?
2018 */
2019 if ((WFileName == NULL || print) && (isatty(1) || lflag))
2020 timeout = 100;
2021
2022 #ifdef WITH_CHROOT
2023 /* if run as root, prepare for chrooting */
2024 if (getuid() == 0 || geteuid() == 0) {
2025 /* future extensibility for cmd-line arguments */
2026 if (!chroot_dir)
2027 chroot_dir = WITH_CHROOT;
2028 }
2029 #endif
2030
2031 #ifdef WITH_USER
2032 /* if run as root, prepare for dropping root privileges */
2033 if (getuid() == 0 || geteuid() == 0) {
2034 /* Run with '-Z root' to restore old behaviour */
2035 if (!username)
2036 username = WITH_USER;
2037 }
2038 #endif
2039
2040 if (RFileName != NULL || VFileName != NULL) {
2041 /*
2042 * If RFileName is non-null, it's the pathname of a
2043 * savefile to read. If VFileName is non-null, it's
2044 * the pathname of a file containing a list of pathnames
2045 * (one per line) of savefiles to read.
2046 *
2047 * In either case, we're reading a savefile, not doing
2048 * a live capture.
2049 */
2050 #ifndef _WIN32
2051 /*
2052 * We don't need network access, so relinquish any set-UID
2053 * or set-GID privileges we have (if any).
2054 *
2055 * We do *not* want set-UID privileges when opening a
2056 * trace file, as that might let the user read other
2057 * people's trace files (especially if we're set-UID
2058 * root).
2059 */
2060 if (setgid(getgid()) != 0 || setuid(getuid()) != 0 )
2061 fprintf(stderr, "Warning: setgid/setuid failed !\n");
2062 #endif /* _WIN32 */
2063 if (VFileName != NULL) {
2064 if (VFileName[0] == '-' && VFileName[1] == '\0')
2065 VFile = stdin;
2066 else
2067 VFile = fopen(VFileName, "r");
2068
2069 if (VFile == NULL)
2070 error("Unable to open file: %s\n", pcap_strerror(errno));
2071
2072 ret = get_next_file(VFile, VFileLine);
2073 if (!ret)
2074 error("Nothing in %s\n", VFileName);
2075 RFileName = VFileLine;
2076 }
2077
2078 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
2079 pd = pcap_open_offline_with_tstamp_precision(RFileName,
2080 ndo->ndo_tstamp_precision, ebuf);
2081 #else
2082 pd = pcap_open_offline(RFileName, ebuf);
2083 #endif
2084
2085 if (pd == NULL)
2086 error("%s", ebuf);
2087 #ifdef HAVE_CAPSICUM
2088 cap_rights_init(&rights, CAP_READ);
2089 if (cap_rights_limit(fileno(pcap_file(pd)), &rights) < 0 &&
2090 errno != ENOSYS) {
2091 error("unable to limit pcap descriptor");
2092 }
2093 #endif
2094 dlt = pcap_datalink(pd);
2095 dlt_name = pcap_datalink_val_to_name(dlt);
2096 fprintf(stderr, "reading from file %s", RFileName);
2097 if (dlt_name == NULL) {
2098 fprintf(stderr, ", link-type %u", dlt);
2099 } else {
2100 fprintf(stderr, ", link-type %s (%s)", dlt_name,
2101 pcap_datalink_val_to_description(dlt));
2102 }
2103 fprintf(stderr, ", snapshot length %d\n", pcap_snapshot(pd));
2104 #ifdef DLT_LINUX_SLL2
2105 if (dlt == DLT_LINUX_SLL2)
2106 fprintf(stderr, "Warning: interface names might be incorrect\n");
2107 #endif
2108 } else if (dflag && !device) {
2109 int dump_dlt = DLT_EN10MB;
2110 /*
2111 * We're dumping the compiled code without an explicit
2112 * device specification. (If a device is specified, we
2113 * definitely want to open it to use the DLT of that device.)
2114 * Either default to DLT_EN10MB with a warning, or use
2115 * the user-specified value if supplied.
2116 */
2117 /*
2118 * If no snapshot length was specified, or a length of 0 was
2119 * specified, default to 256KB.
2120 */
2121 if (ndo->ndo_snaplen == 0)
2122 ndo->ndo_snaplen = MAXIMUM_SNAPLEN;
2123 /*
2124 * If a DLT was specified with the -y flag, use that instead.
2125 */
2126 if (yflag_dlt != -1)
2127 dump_dlt = yflag_dlt;
2128 else
2129 fprintf(stderr, "Warning: assuming Ethernet\n");
2130 pd = pcap_open_dead(dump_dlt, ndo->ndo_snaplen);
2131 } else {
2132 /*
2133 * We're doing a live capture.
2134 */
2135 if (device == NULL) {
2136 /*
2137 * No interface was specified. Pick one.
2138 */
2139 #ifdef HAVE_PCAP_FINDALLDEVS
2140 /*
2141 * Find the list of interfaces, and pick
2142 * the first interface.
2143 */
2144 if (pcap_findalldevs(&devlist, ebuf) == -1)
2145 error("%s", ebuf);
2146 if (devlist == NULL)
2147 error("no interfaces available for capture");
2148 device = strdup(devlist->name);
2149 pcap_freealldevs(devlist);
2150 #else /* HAVE_PCAP_FINDALLDEVS */
2151 /*
2152 * Use whatever interface pcap_lookupdev()
2153 * chooses.
2154 */
2155 device = pcap_lookupdev(ebuf);
2156 if (device == NULL)
2157 error("%s", ebuf);
2158 #endif
2159 }
2160
2161 /*
2162 * Try to open the interface with the specified name.
2163 */
2164 pd = open_interface(device, ndo, ebuf);
2165 if (pd == NULL) {
2166 /*
2167 * That failed. If we can get a list of
2168 * interfaces, and the interface name
2169 * is purely numeric, try to use it as
2170 * a 1-based index in the list of
2171 * interfaces.
2172 */
2173 #ifdef HAVE_PCAP_FINDALLDEVS
2174 devnum = parse_interface_number(device);
2175 if (devnum == -1) {
2176 /*
2177 * It's not a number; just report
2178 * the open error and fail.
2179 */
2180 error("%s", ebuf);
2181 }
2182
2183 /*
2184 * OK, it's a number; try to find the
2185 * interface with that index, and try
2186 * to open it.
2187 *
2188 * find_interface_by_number() exits if it
2189 * couldn't be found.
2190 */
2191 device = find_interface_by_number(device, devnum);
2192 pd = open_interface(device, ndo, ebuf);
2193 if (pd == NULL)
2194 error("%s", ebuf);
2195 #else /* HAVE_PCAP_FINDALLDEVS */
2196 /*
2197 * We can't get a list of interfaces; just
2198 * fail.
2199 */
2200 error("%s", ebuf);
2201 #endif /* HAVE_PCAP_FINDALLDEVS */
2202 }
2203
2204 /*
2205 * Let user own process after capture device has
2206 * been opened.
2207 */
2208 #ifndef _WIN32
2209 if (setgid(getgid()) != 0 || setuid(getuid()) != 0)
2210 fprintf(stderr, "Warning: setgid/setuid failed !\n");
2211 #endif /* _WIN32 */
2212 #if !defined(HAVE_PCAP_CREATE) && defined(_WIN32)
2213 if(Bflag != 0)
2214 if(pcap_setbuff(pd, Bflag)==-1){
2215 error("%s", pcap_geterr(pd));
2216 }
2217 #endif /* !defined(HAVE_PCAP_CREATE) && defined(_WIN32) */
2218 if (Lflag)
2219 show_dlts_and_exit(pd, device);
2220 if (yflag_dlt >= 0) {
2221 #ifdef HAVE_PCAP_SET_DATALINK
2222 if (pcap_set_datalink(pd, yflag_dlt) < 0)
2223 error("%s", pcap_geterr(pd));
2224 #else
2225 /*
2226 * We don't actually support changing the
2227 * data link type, so we only let them
2228 * set it to what it already is.
2229 */
2230 if (yflag_dlt != pcap_datalink(pd)) {
2231 error("%s is not one of the DLTs supported by this device\n",
2232 yflag_dlt_name);
2233 }
2234 #endif
2235 (void)fprintf(stderr, "%s: data link type %s\n",
2236 program_name,
2237 pcap_datalink_val_to_name(yflag_dlt));
2238 (void)fflush(stderr);
2239 }
2240 i = pcap_snapshot(pd);
2241 if (ndo->ndo_snaplen < i) {
2242 if (ndo->ndo_snaplen != 0)
2243 warning("snaplen raised from %d to %d", ndo->ndo_snaplen, i);
2244 ndo->ndo_snaplen = i;
2245 } else if (ndo->ndo_snaplen > i) {
2246 warning("snaplen lowered from %d to %d", ndo->ndo_snaplen, i);
2247 ndo->ndo_snaplen = i;
2248 }
2249 if(ndo->ndo_fflag != 0) {
2250 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
2251 warning("foreign (-f) flag used but: %s", ebuf);
2252 }
2253 }
2254
2255 }
2256 if (infile)
2257 cmdbuf = read_infile(infile);
2258 else
2259 cmdbuf = copy_argv(&argv[optind]);
2260
2261 #ifdef HAVE_PCAP_SET_OPTIMIZER_DEBUG
2262 pcap_set_optimizer_debug(dflag);
2263 #endif
2264 if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
2265 error("%s", pcap_geterr(pd));
2266 if (dflag) {
2267 bpf_dump(&fcode, dflag);
2268 pcap_close(pd);
2269 free(cmdbuf);
2270 pcap_freecode(&fcode);
2271 exit_tcpdump(S_SUCCESS);
2272 }
2273
2274 #ifdef HAVE_CASPER
2275 if (!ndo->ndo_nflag)
2276 capdns = capdns_setup();
2277 #endif /* HAVE_CASPER */
2278
2279 init_print(ndo, localnet, netmask);
2280
2281 #ifndef _WIN32
2282 (void)setsignal(SIGPIPE, cleanup);
2283 (void)setsignal(SIGTERM, cleanup);
2284 #endif /* _WIN32 */
2285 (void)setsignal(SIGINT, cleanup);
2286 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
2287 (void)setsignal(SIGCHLD, child_cleanup);
2288 #endif
2289 /* Cooperate with nohup(1) */
2290 #ifndef _WIN32
2291 if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
2292 (void)setsignal(SIGHUP, oldhandler);
2293 #endif /* _WIN32 */
2294
2295 #ifndef _WIN32
2296 /*
2297 * If a user name was specified with "-Z", attempt to switch to
2298 * that user's UID. This would probably be used with sudo,
2299 * to allow tcpdump to be run in a special restricted
2300 * account (if you just want to allow users to open capture
2301 * devices, and can't just give users that permission,
2302 * you'd make tcpdump set-UID or set-GID).
2303 *
2304 * Tcpdump doesn't necessarily write only to one savefile;
2305 * the general only way to allow a -Z instance to write to
2306 * savefiles as the user under whose UID it's run, rather
2307 * than as the user specified with -Z, would thus be to switch
2308 * to the original user ID before opening a capture file and
2309 * then switch back to the -Z user ID after opening the savefile.
2310 * Switching to the -Z user ID only after opening the first
2311 * savefile doesn't handle the general case.
2312 */
2313
2314 if (getuid() == 0 || geteuid() == 0) {
2315 #ifdef HAVE_LIBCAP_NG
2316 /* Initialize capng */
2317 capng_clear(CAPNG_SELECT_BOTH);
2318 if (username) {
2319 DIAG_OFF_ASSIGN_ENUM
2320 capng_updatev(
2321 CAPNG_ADD,
2322 CAPNG_PERMITTED | CAPNG_EFFECTIVE,
2323 CAP_SETUID,
2324 CAP_SETGID,
2325 -1);
2326 DIAG_ON_ASSIGN_ENUM
2327 }
2328 if (chroot_dir) {
2329 DIAG_OFF_ASSIGN_ENUM
2330 capng_update(
2331 CAPNG_ADD,
2332 CAPNG_PERMITTED | CAPNG_EFFECTIVE,
2333 CAP_SYS_CHROOT
2334 );
2335 DIAG_ON_ASSIGN_ENUM
2336 }
2337
2338 if (WFileName) {
2339 DIAG_OFF_ASSIGN_ENUM
2340 capng_update(
2341 CAPNG_ADD,
2342 CAPNG_PERMITTED | CAPNG_EFFECTIVE,
2343 CAP_DAC_OVERRIDE
2344 );
2345 DIAG_ON_ASSIGN_ENUM
2346 }
2347 capng_apply(CAPNG_SELECT_BOTH);
2348 #endif /* HAVE_LIBCAP_NG */
2349 if (username || chroot_dir)
2350 droproot(username, chroot_dir);
2351
2352 }
2353 #endif /* _WIN32 */
2354
2355 if (pcap_setfilter(pd, &fcode) < 0)
2356 error("%s", pcap_geterr(pd));
2357 #ifdef HAVE_CAPSICUM
2358 if (RFileName == NULL && VFileName == NULL && pcap_fileno(pd) != -1) {
2359 static const unsigned long cmds[] = { BIOCGSTATS, BIOCROTZBUF };
2360
2361 /*
2362 * The various libpcap devices use a combination of
2363 * read (bpf), ioctl (bpf, netmap), poll (netmap)
2364 * so we add the relevant access rights.
2365 */
2366 cap_rights_init(&rights, CAP_IOCTL, CAP_READ, CAP_EVENT);
2367 if (cap_rights_limit(pcap_fileno(pd), &rights) < 0 &&
2368 errno != ENOSYS) {
2369 error("unable to limit pcap descriptor");
2370 }
2371 if (cap_ioctls_limit(pcap_fileno(pd), cmds,
2372 sizeof(cmds) / sizeof(cmds[0])) < 0 && errno != ENOSYS) {
2373 error("unable to limit ioctls on pcap descriptor");
2374 }
2375 }
2376 #endif
2377 if (WFileName) {
2378 /* Do not exceed the default PATH_MAX for files. */
2379 dumpinfo.CurrentFileName = (char *)malloc(PATH_MAX + 1);
2380
2381 if (dumpinfo.CurrentFileName == NULL)
2382 error("malloc of dumpinfo.CurrentFileName");
2383
2384 /* We do not need numbering for dumpfiles if Cflag isn't set. */
2385 if (Cflag != 0)
2386 MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, WflagChars);
2387 else
2388 MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, 0);
2389
2390 pdd = pcap_dump_open(pd, dumpinfo.CurrentFileName);
2391 #ifdef HAVE_LIBCAP_NG
2392 /* Give up CAP_DAC_OVERRIDE capability.
2393 * Only allow it to be restored if the -C or -G flag have been
2394 * set since we may need to create more files later on.
2395 */
2396 capng_update(
2397 CAPNG_DROP,
2398 (Cflag || Gflag ? 0 : CAPNG_PERMITTED)
2399 | CAPNG_EFFECTIVE,
2400 CAP_DAC_OVERRIDE
2401 );
2402 capng_apply(CAPNG_SELECT_BOTH);
2403 #endif /* HAVE_LIBCAP_NG */
2404 if (pdd == NULL)
2405 error("%s", pcap_geterr(pd));
2406 #ifdef HAVE_CAPSICUM
2407 set_dumper_capsicum_rights(pdd);
2408 #endif
2409 if (Cflag != 0 || Gflag != 0) {
2410 #ifdef HAVE_CAPSICUM
2411 /*
2412 * basename() and dirname() may modify their input buffer
2413 * and they do since FreeBSD 12.0, but they didn't before.
2414 * Hence use the return value only, but always assume the
2415 * input buffer has been modified and would need to be
2416 * reset before the next use.
2417 */
2418 char *WFileName_copy;
2419
2420 if ((WFileName_copy = strdup(WFileName)) == NULL) {
2421 error("Unable to allocate memory for file %s",
2422 WFileName);
2423 }
2424 DIAG_OFF_C11_EXTENSIONS
2425 dumpinfo.WFileName = strdup(basename(WFileName_copy));
2426 DIAG_ON_C11_EXTENSIONS
2427 if (dumpinfo.WFileName == NULL) {
2428 error("Unable to allocate memory for file %s",
2429 WFileName);
2430 }
2431 free(WFileName_copy);
2432
2433 if ((WFileName_copy = strdup(WFileName)) == NULL) {
2434 error("Unable to allocate memory for file %s",
2435 WFileName);
2436 }
2437 DIAG_OFF_C11_EXTENSIONS
2438 char *WFileName_dirname = dirname(WFileName_copy);
2439 DIAG_ON_C11_EXTENSIONS
2440 dumpinfo.dirfd = open(WFileName_dirname,
2441 O_DIRECTORY | O_RDONLY);
2442 if (dumpinfo.dirfd < 0) {
2443 error("unable to open directory %s",
2444 WFileName_dirname);
2445 }
2446 free(WFileName_dirname);
2447 free(WFileName_copy);
2448
2449 cap_rights_init(&rights, CAP_CREATE, CAP_FCNTL,
2450 CAP_FTRUNCATE, CAP_LOOKUP, CAP_SEEK, CAP_WRITE);
2451 if (cap_rights_limit(dumpinfo.dirfd, &rights) < 0 &&
2452 errno != ENOSYS) {
2453 error("unable to limit directory rights");
2454 }
2455 if (cap_fcntls_limit(dumpinfo.dirfd, CAP_FCNTL_GETFL) < 0 &&
2456 errno != ENOSYS) {
2457 error("unable to limit dump descriptor fcntls");
2458 }
2459 #else /* !HAVE_CAPSICUM */
2460 dumpinfo.WFileName = WFileName;
2461 #endif
2462 callback = dump_packet_and_trunc;
2463 dumpinfo.pd = pd;
2464 dumpinfo.pdd = pdd;
2465 pcap_userdata = (u_char *)&dumpinfo;
2466 } else {
2467 callback = dump_packet;
2468 dumpinfo.WFileName = WFileName;
2469 dumpinfo.pd = pd;
2470 dumpinfo.pdd = pdd;
2471 pcap_userdata = (u_char *)&dumpinfo;
2472 }
2473 if (print) {
2474 dlt = pcap_datalink(pd);
2475 ndo->ndo_if_printer = get_if_printer(dlt);
2476 dumpinfo.ndo = ndo;
2477 } else
2478 dumpinfo.ndo = NULL;
2479
2480 #ifdef HAVE_PCAP_DUMP_FLUSH
2481 if (Uflag)
2482 pcap_dump_flush(pdd);
2483 #endif
2484 } else {
2485 dlt = pcap_datalink(pd);
2486 ndo->ndo_if_printer = get_if_printer(dlt);
2487 callback = print_packet;
2488 pcap_userdata = (u_char *)ndo;
2489 }
2490
2491 #ifdef SIGNAL_REQ_INFO
2492 /*
2493 * We can't get statistics when reading from a file rather
2494 * than capturing from a device.
2495 */
2496 if (RFileName == NULL)
2497 (void)setsignal(SIGNAL_REQ_INFO, requestinfo);
2498 #endif
2499 #ifdef SIGNAL_FLUSH_PCAP
2500 (void)setsignal(SIGNAL_FLUSH_PCAP, flushpcap);
2501 #endif
2502
2503 if (ndo->ndo_vflag > 0 && WFileName && RFileName == NULL && !print) {
2504 /*
2505 * When capturing to a file, if "--print" wasn't specified,
2506 *"-v" means tcpdump should, once per second,
2507 * "v"erbosely report the number of packets captured.
2508 * Except when reading from a file, because -r, -w and -v
2509 * together used to make a corner case, in which pcap_loop()
2510 * errored due to EINTR (see GH #155 for details).
2511 */
2512 #ifdef _WIN32
2513 /*
2514 * https://blogs.msdn.microsoft.com/oldnewthing/20151230-00/?p=92741
2515 *
2516 * suggests that this dates back to W2K.
2517 *
2518 * I don't know what a "long wait" is, but we'll assume
2519 * that printing the stats could be a "long wait".
2520 */
2521 CreateTimerQueueTimer(&timer_handle, NULL,
2522 verbose_stats_dump, NULL, 1000, 1000,
2523 WT_EXECUTEDEFAULT|WT_EXECUTELONGFUNCTION);
2524 setvbuf(stderr, NULL, _IONBF, 0);
2525 #else /* _WIN32 */
2526 /*
2527 * Assume this is UN*X, and that it has setitimer(); that
2528 * dates back to UNIX 95.
2529 */
2530 struct itimerval timer;
2531 (void)setsignal(SIGALRM, verbose_stats_dump);
2532 timer.it_interval.tv_sec = 1;
2533 timer.it_interval.tv_usec = 0;
2534 timer.it_value.tv_sec = 1;
2535 timer.it_value.tv_usec = 1;
2536 setitimer(ITIMER_REAL, &timer, NULL);
2537 #endif /* _WIN32 */
2538 }
2539
2540 if (RFileName == NULL) {
2541 /*
2542 * Live capture (if -V was specified, we set RFileName
2543 * to a file from the -V file). Print a message to
2544 * the standard error on UN*X.
2545 */
2546 if (!ndo->ndo_vflag && !WFileName) {
2547 (void)fprintf(stderr,
2548 "%s: verbose output suppressed, use -v[v]... for full protocol decode\n",
2549 program_name);
2550 } else
2551 (void)fprintf(stderr, "%s: ", program_name);
2552 dlt = pcap_datalink(pd);
2553 dlt_name = pcap_datalink_val_to_name(dlt);
2554 (void)fprintf(stderr, "listening on %s", device);
2555 if (dlt_name == NULL) {
2556 (void)fprintf(stderr, ", link-type %u", dlt);
2557 } else {
2558 (void)fprintf(stderr, ", link-type %s (%s)", dlt_name,
2559 pcap_datalink_val_to_description(dlt));
2560 }
2561 (void)fprintf(stderr, ", snapshot length %d bytes\n", ndo->ndo_snaplen);
2562 (void)fflush(stderr);
2563 }
2564
2565 #ifdef HAVE_CAPSICUM
2566 cansandbox = (VFileName == NULL && zflag == NULL &&
2567 ndo->ndo_espsecret == NULL);
2568 #ifdef HAVE_CASPER
2569 cansandbox = (cansandbox && (ndo->ndo_nflag || capdns != NULL));
2570 #else
2571 cansandbox = (cansandbox && ndo->ndo_nflag);
2572 #endif /* HAVE_CASPER */
2573 cansandbox = (cansandbox && (pcap_fileno(pd) != -1 ||
2574 RFileName != NULL));
2575
2576 if (cansandbox && cap_enter() < 0 && errno != ENOSYS)
2577 error("unable to enter the capability mode");
2578 #endif /* HAVE_CAPSICUM */
2579
2580 do {
2581 status = pcap_loop(pd, cnt, callback, pcap_userdata);
2582 if (WFileName == NULL) {
2583 /*
2584 * We're printing packets. Flush the printed output,
2585 * so it doesn't get intermingled with error output.
2586 */
2587 if (status == -2) {
2588 /*
2589 * We got interrupted, so perhaps we didn't
2590 * manage to finish a line we were printing.
2591 * Print an extra newline, just in case.
2592 */
2593 putchar('\n');
2594 }
2595 (void)fflush(stdout);
2596 }
2597 if (status == -2) {
2598 /*
2599 * We got interrupted. If we are reading multiple
2600 * files (via -V) set these so that we stop.
2601 */
2602 VFileName = NULL;
2603 ret = NULL;
2604 }
2605 if (status == -1) {
2606 /*
2607 * Error. Report it.
2608 */
2609 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
2610 program_name, pcap_geterr(pd));
2611 }
2612 if (RFileName == NULL) {
2613 /*
2614 * We're doing a live capture. Report the capture
2615 * statistics.
2616 */
2617 info(1);
2618 }
2619 pcap_close(pd);
2620 if (VFileName != NULL) {
2621 ret = get_next_file(VFile, VFileLine);
2622 if (ret) {
2623 int new_dlt;
2624
2625 RFileName = VFileLine;
2626 pd = pcap_open_offline(RFileName, ebuf);
2627 if (pd == NULL)
2628 error("%s", ebuf);
2629 #ifdef HAVE_CAPSICUM
2630 cap_rights_init(&rights, CAP_READ);
2631 if (cap_rights_limit(fileno(pcap_file(pd)),
2632 &rights) < 0 && errno != ENOSYS) {
2633 error("unable to limit pcap descriptor");
2634 }
2635 #endif
2636 new_dlt = pcap_datalink(pd);
2637 if (new_dlt != dlt) {
2638 /*
2639 * The new file has a different
2640 * link-layer header type from the
2641 * previous one.
2642 */
2643 if (WFileName != NULL) {
2644 /*
2645 * We're writing raw packets
2646 * that match the filter to
2647 * a pcap file. pcap files
2648 * don't support multiple
2649 * different link-layer
2650 * header types, so we fail
2651 * here.
2652 */
2653 error("%s: new dlt does not match original", RFileName);
2654 }
2655
2656 /*
2657 * We're printing the decoded packets;
2658 * switch to the new DLT.
2659 *
2660 * To do that, we need to change
2661 * the printer, change the DLT name,
2662 * and recompile the filter with
2663 * the new DLT.
2664 */
2665 dlt = new_dlt;
2666 ndo->ndo_if_printer = get_if_printer(dlt);
2667 if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
2668 error("%s", pcap_geterr(pd));
2669 }
2670
2671 /*
2672 * Set the filter on the new file.
2673 */
2674 if (pcap_setfilter(pd, &fcode) < 0)
2675 error("%s", pcap_geterr(pd));
2676
2677 /*
2678 * Report the new file.
2679 */
2680 dlt_name = pcap_datalink_val_to_name(dlt);
2681 fprintf(stderr, "reading from file %s", RFileName);
2682 if (dlt_name == NULL) {
2683 fprintf(stderr, ", link-type %u", dlt);
2684 } else {
2685 fprintf(stderr, ", link-type %s (%s)",
2686 dlt_name,
2687 pcap_datalink_val_to_description(dlt));
2688 }
2689 fprintf(stderr, ", snapshot length %d\n", pcap_snapshot(pd));
2690 }
2691 }
2692 }
2693 while (ret != NULL);
2694
2695 if (count_mode && RFileName != NULL)
2696 fprintf(stdout, "%u packet%s\n", packets_captured,
2697 PLURAL_SUFFIX(packets_captured));
2698
2699 free(cmdbuf);
2700 pcap_freecode(&fcode);
2701 exit_tcpdump(status == -1 ? S_ERR_HOST_PROGRAM : S_SUCCESS);
2702 }
2703
2704 /*
2705 * Catch a signal.
2706 */
2707 static void
setsignal(int sig,void (* func)(int))2708 (*setsignal (int sig, void (*func)(int)))(int)
2709 {
2710 #ifdef _WIN32
2711 return (signal(sig, func));
2712 #else
2713 struct sigaction old, new;
2714
2715 memset(&new, 0, sizeof(new));
2716 new.sa_handler = func;
2717 if ((sig == SIGCHLD)
2718 # ifdef SIGNAL_REQ_INFO
2719 || (sig == SIGNAL_REQ_INFO)
2720 # endif
2721 # ifdef SIGNAL_FLUSH_PCAP
2722 || (sig == SIGNAL_FLUSH_PCAP)
2723 # endif
2724 )
2725 new.sa_flags = SA_RESTART;
2726 if (sigaction(sig, &new, &old) < 0)
2727 return (SIG_ERR);
2728 return (old.sa_handler);
2729 #endif
2730 }
2731
2732 /* make a clean exit on interrupts */
2733 static void
cleanup(int signo _U_)2734 cleanup(int signo _U_)
2735 {
2736 #ifdef _WIN32
2737 if (timer_handle != INVALID_HANDLE_VALUE) {
2738 DeleteTimerQueueTimer(NULL, timer_handle, NULL);
2739 CloseHandle(timer_handle);
2740 timer_handle = INVALID_HANDLE_VALUE;
2741 }
2742 #else /* _WIN32 */
2743 struct itimerval timer;
2744
2745 timer.it_interval.tv_sec = 0;
2746 timer.it_interval.tv_usec = 0;
2747 timer.it_value.tv_sec = 0;
2748 timer.it_value.tv_usec = 0;
2749 setitimer(ITIMER_REAL, &timer, NULL);
2750 #endif /* _WIN32 */
2751
2752 #ifdef HAVE_PCAP_BREAKLOOP
2753 /*
2754 * We have "pcap_breakloop()"; use it, so that we do as little
2755 * as possible in the signal handler (it's probably not safe
2756 * to do anything with standard I/O streams in a signal handler -
2757 * the ANSI C standard doesn't say it is).
2758 */
2759 pcap_breakloop(pd);
2760 #else
2761 /*
2762 * We don't have "pcap_breakloop()"; this isn't safe, but
2763 * it's the best we can do. Print the summary if we're
2764 * not reading from a savefile - i.e., if we're doing a
2765 * live capture - and exit.
2766 */
2767 if (pd != NULL && pcap_file(pd) == NULL) {
2768 /*
2769 * We got interrupted, so perhaps we didn't
2770 * manage to finish a line we were printing.
2771 * Print an extra newline, just in case.
2772 */
2773 putchar('\n');
2774 (void)fflush(stdout);
2775 info(1);
2776 }
2777 exit_tcpdump(S_SUCCESS);
2778 #endif
2779 }
2780
2781 /*
2782 On windows, we do not use a fork, so we do not care less about
2783 waiting a child processes to die
2784 */
2785 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
2786 static void
child_cleanup(int signo _U_)2787 child_cleanup(int signo _U_)
2788 {
2789 wait(NULL);
2790 }
2791 #endif /* HAVE_FORK && HAVE_VFORK */
2792
2793 static void
info(int verbose)2794 info(int verbose)
2795 {
2796 struct pcap_stat stats;
2797
2798 /*
2799 * Older versions of libpcap didn't set ps_ifdrop on some
2800 * platforms; initialize it to 0 to handle that.
2801 */
2802 stats.ps_ifdrop = 0;
2803 if (pcap_stats(pd, &stats) < 0) {
2804 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
2805 infoprint = 0;
2806 return;
2807 }
2808
2809 if (!verbose)
2810 fprintf(stderr, "%s: ", program_name);
2811
2812 (void)fprintf(stderr, "%u packet%s captured", packets_captured,
2813 PLURAL_SUFFIX(packets_captured));
2814 if (!verbose)
2815 fputs(", ", stderr);
2816 else
2817 putc('\n', stderr);
2818 (void)fprintf(stderr, "%u packet%s received by filter", stats.ps_recv,
2819 PLURAL_SUFFIX(stats.ps_recv));
2820 if (!verbose)
2821 fputs(", ", stderr);
2822 else
2823 putc('\n', stderr);
2824 (void)fprintf(stderr, "%u packet%s dropped by kernel", stats.ps_drop,
2825 PLURAL_SUFFIX(stats.ps_drop));
2826 if (stats.ps_ifdrop != 0) {
2827 if (!verbose)
2828 fputs(", ", stderr);
2829 else
2830 putc('\n', stderr);
2831 (void)fprintf(stderr, "%u packet%s dropped by interface\n",
2832 stats.ps_ifdrop, PLURAL_SUFFIX(stats.ps_ifdrop));
2833 } else
2834 putc('\n', stderr);
2835 infoprint = 0;
2836 }
2837
2838 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
2839 #ifdef HAVE_FORK
2840 #define fork_subprocess() fork()
2841 #else
2842 #define fork_subprocess() vfork()
2843 #endif
2844 static void
compress_savefile(const char * filename)2845 compress_savefile(const char *filename)
2846 {
2847 pid_t child;
2848
2849 child = fork_subprocess();
2850 if (child == -1) {
2851 fprintf(stderr,
2852 "compress_savefile: fork failed: %s\n",
2853 pcap_strerror(errno));
2854 return;
2855 }
2856 if (child != 0) {
2857 /* Parent process. */
2858 return;
2859 }
2860
2861 /*
2862 * Child process.
2863 * Set to lowest priority so that this doesn't disturb the capture.
2864 */
2865 #ifdef NZERO
2866 setpriority(PRIO_PROCESS, 0, NZERO - 1);
2867 #else
2868 setpriority(PRIO_PROCESS, 0, 19);
2869 #endif
2870 if (execlp(zflag, zflag, filename, (char *)NULL) == -1)
2871 fprintf(stderr,
2872 "compress_savefile: execlp(%s, %s) failed: %s\n",
2873 zflag,
2874 filename,
2875 pcap_strerror(errno));
2876 #ifdef HAVE_FORK
2877 exit(S_ERR_HOST_PROGRAM);
2878 #else
2879 _exit(S_ERR_HOST_PROGRAM);
2880 #endif
2881 }
2882 #else /* HAVE_FORK && HAVE_VFORK */
2883 static void
compress_savefile(const char * filename)2884 compress_savefile(const char *filename)
2885 {
2886 fprintf(stderr,
2887 "compress_savefile failed. Functionality not implemented under your system\n");
2888 }
2889 #endif /* HAVE_FORK && HAVE_VFORK */
2890
2891 static void
dump_packet_and_trunc(u_char * user,const struct pcap_pkthdr * h,const u_char * sp)2892 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
2893 {
2894 struct dump_info *dump_info;
2895
2896 ++packets_captured;
2897
2898 ++infodelay;
2899
2900 dump_info = (struct dump_info *)user;
2901
2902 /*
2903 * XXX - this won't force the file to rotate on the specified time
2904 * boundary, but it will rotate on the first packet received after the
2905 * specified Gflag number of seconds. Note: if a Gflag time boundary
2906 * and a Cflag size boundary coincide, the time rotation will occur
2907 * first thereby cancelling the Cflag boundary (since the file should
2908 * be 0).
2909 */
2910 if (Gflag != 0) {
2911 /* Check if it is time to rotate */
2912 time_t t;
2913
2914 /* Get the current time */
2915 if ((t = time(NULL)) == (time_t)-1) {
2916 error("%s: can't get current_time: %s",
2917 __func__, pcap_strerror(errno));
2918 }
2919
2920
2921 /* If the time is greater than the specified window, rotate */
2922 if (t - Gflag_time >= Gflag) {
2923 #ifdef HAVE_CAPSICUM
2924 FILE *fp;
2925 int fd;
2926 #endif
2927
2928 /* Update the Gflag_time */
2929 Gflag_time = t;
2930 /* Update Gflag_count */
2931 Gflag_count++;
2932 /*
2933 * Close the current file and open a new one.
2934 */
2935 pcap_dump_close(dump_info->pdd);
2936
2937 /*
2938 * Compress the file we just closed, if the user asked for it
2939 */
2940 if (zflag != NULL)
2941 compress_savefile(dump_info->CurrentFileName);
2942
2943 /*
2944 * Check to see if we've exceeded the Wflag (when
2945 * not using Cflag).
2946 */
2947 if (Cflag == 0 && Wflag > 0 && Gflag_count >= Wflag) {
2948 (void)fprintf(stderr, "Maximum file limit reached: %d\n",
2949 Wflag);
2950 info(1);
2951 exit_tcpdump(S_SUCCESS);
2952 /* NOTREACHED */
2953 }
2954 if (dump_info->CurrentFileName != NULL)
2955 free(dump_info->CurrentFileName);
2956 /* Allocate space for max filename + \0. */
2957 dump_info->CurrentFileName = (char *)malloc(PATH_MAX + 1);
2958 if (dump_info->CurrentFileName == NULL)
2959 error("dump_packet_and_trunc: malloc");
2960 /*
2961 * Gflag was set otherwise we wouldn't be here. Reset the count
2962 * so multiple files would end with 1,2,3 in the filename.
2963 * The counting is handled with the -C flow after this.
2964 */
2965 Cflag_count = 0;
2966
2967 /*
2968 * This is always the first file in the Cflag
2969 * rotation: e.g. 0
2970 * We also don't need numbering if Cflag is not set.
2971 */
2972 if (Cflag != 0)
2973 MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, 0,
2974 WflagChars);
2975 else
2976 MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, 0, 0);
2977
2978 #ifdef HAVE_LIBCAP_NG
2979 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
2980 capng_apply(CAPNG_SELECT_BOTH);
2981 #endif /* HAVE_LIBCAP_NG */
2982 #ifdef HAVE_CAPSICUM
2983 fd = openat(dump_info->dirfd,
2984 dump_info->CurrentFileName,
2985 O_CREAT | O_WRONLY | O_TRUNC, 0644);
2986 if (fd < 0) {
2987 error("unable to open file %s",
2988 dump_info->CurrentFileName);
2989 }
2990 fp = fdopen(fd, "w");
2991 if (fp == NULL) {
2992 error("unable to fdopen file %s",
2993 dump_info->CurrentFileName);
2994 }
2995 dump_info->pdd = pcap_dump_fopen(dump_info->pd, fp);
2996 #else /* !HAVE_CAPSICUM */
2997 dump_info->pdd = pcap_dump_open(dump_info->pd, dump_info->CurrentFileName);
2998 #endif
2999 #ifdef HAVE_LIBCAP_NG
3000 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
3001 capng_apply(CAPNG_SELECT_BOTH);
3002 #endif /* HAVE_LIBCAP_NG */
3003 if (dump_info->pdd == NULL)
3004 error("%s", pcap_geterr(pd));
3005 #ifdef HAVE_CAPSICUM
3006 set_dumper_capsicum_rights(dump_info->pdd);
3007 #endif
3008 }
3009 }
3010
3011 /*
3012 * XXX - this won't prevent capture files from getting
3013 * larger than Cflag - the last packet written to the
3014 * file could put it over Cflag.
3015 */
3016 if (Cflag != 0) {
3017 #ifdef HAVE_PCAP_DUMP_FTELL64
3018 int64_t size = pcap_dump_ftell64(dump_info->pdd);
3019 #else
3020 /*
3021 * XXX - this only handles a Cflag value > 2^31-1 on
3022 * LP64 platforms; to handle ILP32 (32-bit UN*X and
3023 * Windows) or LLP64 (64-bit Windows) would require
3024 * a version of libpcap with pcap_dump_ftell64().
3025 */
3026 long size = pcap_dump_ftell(dump_info->pdd);
3027 #endif
3028
3029 if (size == -1)
3030 error("ftell fails on output file");
3031 if (size > Cflag) {
3032 #ifdef HAVE_CAPSICUM
3033 FILE *fp;
3034 int fd;
3035 #endif
3036
3037 /*
3038 * Close the current file and open a new one.
3039 */
3040 pcap_dump_close(dump_info->pdd);
3041
3042 /*
3043 * Compress the file we just closed, if the user
3044 * asked for it.
3045 */
3046 if (zflag != NULL)
3047 compress_savefile(dump_info->CurrentFileName);
3048
3049 Cflag_count++;
3050 if (Wflag > 0) {
3051 if (Cflag_count >= Wflag)
3052 Cflag_count = 0;
3053 }
3054 if (dump_info->CurrentFileName != NULL)
3055 free(dump_info->CurrentFileName);
3056 dump_info->CurrentFileName = (char *)malloc(PATH_MAX + 1);
3057 if (dump_info->CurrentFileName == NULL)
3058 error("%s: malloc", __func__);
3059 MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, Cflag_count, WflagChars);
3060 #ifdef HAVE_LIBCAP_NG
3061 capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
3062 capng_apply(CAPNG_SELECT_BOTH);
3063 #endif /* HAVE_LIBCAP_NG */
3064 #ifdef HAVE_CAPSICUM
3065 fd = openat(dump_info->dirfd, dump_info->CurrentFileName,
3066 O_CREAT | O_WRONLY | O_TRUNC, 0644);
3067 if (fd < 0) {
3068 error("unable to open file %s",
3069 dump_info->CurrentFileName);
3070 }
3071 fp = fdopen(fd, "w");
3072 if (fp == NULL) {
3073 error("unable to fdopen file %s",
3074 dump_info->CurrentFileName);
3075 }
3076 dump_info->pdd = pcap_dump_fopen(dump_info->pd, fp);
3077 #else /* !HAVE_CAPSICUM */
3078 dump_info->pdd = pcap_dump_open(dump_info->pd, dump_info->CurrentFileName);
3079 #endif
3080 #ifdef HAVE_LIBCAP_NG
3081 capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
3082 capng_apply(CAPNG_SELECT_BOTH);
3083 #endif /* HAVE_LIBCAP_NG */
3084 if (dump_info->pdd == NULL)
3085 error("%s", pcap_geterr(pd));
3086 #ifdef HAVE_CAPSICUM
3087 set_dumper_capsicum_rights(dump_info->pdd);
3088 #endif
3089 }
3090 }
3091
3092 pcap_dump((u_char *)dump_info->pdd, h, sp);
3093 #ifdef HAVE_PCAP_DUMP_FLUSH
3094 if (Uflag)
3095 pcap_dump_flush(dump_info->pdd);
3096 #endif
3097
3098 if (dump_info->ndo != NULL)
3099 pretty_print_packet(dump_info->ndo, h, sp, packets_captured);
3100
3101 --infodelay;
3102 if (infoprint)
3103 info(0);
3104 }
3105
3106 static void
dump_packet(u_char * user,const struct pcap_pkthdr * h,const u_char * sp)3107 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
3108 {
3109 struct dump_info *dump_info;
3110
3111 ++packets_captured;
3112
3113 ++infodelay;
3114
3115 dump_info = (struct dump_info *)user;
3116
3117 pcap_dump((u_char *)dump_info->pdd, h, sp);
3118 #ifdef HAVE_PCAP_DUMP_FLUSH
3119 if (Uflag)
3120 pcap_dump_flush(dump_info->pdd);
3121 #endif
3122
3123 if (dump_info->ndo != NULL)
3124 pretty_print_packet(dump_info->ndo, h, sp, packets_captured);
3125
3126 --infodelay;
3127 if (infoprint)
3128 info(0);
3129 }
3130
3131 static void
print_packet(u_char * user,const struct pcap_pkthdr * h,const u_char * sp)3132 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
3133 {
3134 ++packets_captured;
3135
3136 ++infodelay;
3137
3138 if (!count_mode)
3139 pretty_print_packet((netdissect_options *)user, h, sp, packets_captured);
3140
3141 --infodelay;
3142 if (infoprint)
3143 info(0);
3144 }
3145
3146 #ifdef SIGNAL_REQ_INFO
3147 static void
requestinfo(int signo _U_)3148 requestinfo(int signo _U_)
3149 {
3150 if (infodelay)
3151 ++infoprint;
3152 else
3153 info(0);
3154 }
3155 #endif
3156
3157 #ifdef SIGNAL_FLUSH_PCAP
3158 static void
flushpcap(int signo _U_)3159 flushpcap(int signo _U_)
3160 {
3161 if (pdd != NULL)
3162 pcap_dump_flush(pdd);
3163 }
3164 #endif
3165
3166 static void
print_packets_captured(void)3167 print_packets_captured (void)
3168 {
3169 static u_int prev_packets_captured, first = 1;
3170
3171 if (infodelay == 0 && (first || packets_captured != prev_packets_captured)) {
3172 fprintf(stderr, "Got %u\r", packets_captured);
3173 first = 0;
3174 prev_packets_captured = packets_captured;
3175 }
3176 }
3177
3178 /*
3179 * Called once each second in verbose mode while dumping to file
3180 */
3181 #ifdef _WIN32
verbose_stats_dump(PVOID param _U_,BOOLEAN timer_fired _U_)3182 static void CALLBACK verbose_stats_dump(PVOID param _U_,
3183 BOOLEAN timer_fired _U_)
3184 {
3185 print_packets_captured();
3186 }
3187 #else /* _WIN32 */
verbose_stats_dump(int sig _U_)3188 static void verbose_stats_dump(int sig _U_)
3189 {
3190 print_packets_captured();
3191 }
3192 #endif /* _WIN32 */
3193
3194 DIAG_OFF_DEPRECATION
3195 static void
print_version(FILE * f)3196 print_version(FILE *f)
3197 {
3198 #ifndef HAVE_PCAP_LIB_VERSION
3199 #ifdef HAVE_PCAP_VERSION
3200 extern char pcap_version[];
3201 #else /* HAVE_PCAP_VERSION */
3202 static char pcap_version[] = "unknown";
3203 #endif /* HAVE_PCAP_VERSION */
3204 #endif /* HAVE_PCAP_LIB_VERSION */
3205 const char *smi_version_string;
3206
3207 (void)fprintf(f, "%s version " PACKAGE_VERSION "\n", program_name);
3208 #ifdef HAVE_PCAP_LIB_VERSION
3209 (void)fprintf(f, "%s\n", pcap_lib_version());
3210 #else /* HAVE_PCAP_LIB_VERSION */
3211 (void)fprintf(f, "libpcap version %s\n", pcap_version);
3212 #endif /* HAVE_PCAP_LIB_VERSION */
3213
3214 #if defined(HAVE_LIBCRYPTO) && defined(SSLEAY_VERSION)
3215 (void)fprintf (f, "%s\n", SSLeay_version(SSLEAY_VERSION));
3216 #endif
3217
3218 smi_version_string = nd_smi_version_string();
3219 if (smi_version_string != NULL)
3220 (void)fprintf (f, "SMI-library: %s\n", smi_version_string);
3221
3222 #if defined(__SANITIZE_ADDRESS__)
3223 (void)fprintf (f, "Compiled with AddressSanitizer/GCC.\n");
3224 #elif defined(__has_feature)
3225 # if __has_feature(address_sanitizer)
3226 (void)fprintf (f, "Compiled with AddressSanitizer/Clang.\n");
3227 # elif __has_feature(memory_sanitizer)
3228 (void)fprintf (f, "Compiled with MemorySanitizer/Clang.\n");
3229 # endif
3230 #endif /* __SANITIZE_ADDRESS__ or __has_feature */
3231 }
3232 DIAG_ON_DEPRECATION
3233
3234 static void
print_usage(FILE * f)3235 print_usage(FILE *f)
3236 {
3237 print_version(f);
3238 (void)fprintf(f,
3239 "Usage: %s [-Abd" D_FLAG "efhH" I_FLAG J_FLAG "KlLnNOpqStu" U_FLAG "vxX#]" B_FLAG_USAGE " [ -c count ] [--count]\n", program_name);
3240 (void)fprintf(f,
3241 "\t\t[ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ]\n");
3242 (void)fprintf(f,
3243 "\t\t[ -i interface ]" IMMEDIATE_MODE_USAGE j_FLAG_USAGE "\n");
3244 #ifdef HAVE_PCAP_FINDALLDEVS_EX
3245 (void)fprintf(f,
3246 "\t\t" LIST_REMOTE_INTERFACES_USAGE "\n");
3247 #endif
3248 #ifdef USE_LIBSMI
3249 (void)fprintf(f,
3250 "\t\t" m_FLAG_USAGE "\n");
3251 #endif
3252 (void)fprintf(f,
3253 "\t\t[ -M secret ] [ --number ] [ --print ]" Q_FLAG_USAGE "\n");
3254 (void)fprintf(f,
3255 "\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ --version ]\n");
3256 (void)fprintf(f,
3257 "\t\t[ -V file ] [ -w file ] [ -W filecount ] [ -y datalinktype ]\n");
3258 #ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
3259 (void)fprintf(f,
3260 "\t\t[ --time-stamp-precision precision ] [ --micro ] [ --nano ]\n");
3261 #endif
3262 (void)fprintf(f,
3263 "\t\t[ -z postrotate-command ] [ -Z user ] [ expression ]\n");
3264 }
3265