xref: /freebsd/contrib/tcpdump/tcpdump.c (revision 6e660824a82f590542932de52f128db584029893)
1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  *
21  * Support for splitting captures into multiple files with a maximum
22  * file size:
23  *
24  * Copyright (c) 2001
25  *	Seth Webster <swebster@sst.ll.mit.edu>
26  */
27 
28 #ifndef lint
29 static const char copyright[] _U_ =
30     "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
31 The Regents of the University of California.  All rights reserved.\n";
32 static const char rcsid[] _U_ =
33     "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.283 2008-09-25 21:45:50 guy Exp $ (LBL)";
34 #endif
35 
36 /* $FreeBSD$ */
37 
38 /*
39  * tcpdump - monitor tcp/ip traffic on an ethernet.
40  *
41  * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
42  * Mercilessly hacked and occasionally improved since then via the
43  * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
44  */
45 
46 #ifdef HAVE_CONFIG_H
47 #include "config.h"
48 #endif
49 
50 #include <tcpdump-stdinc.h>
51 
52 #ifdef WIN32
53 #include "getopt.h"
54 #include "w32_fzs.h"
55 extern int strcasecmp (const char *__s1, const char *__s2);
56 extern int SIZE_BUF;
57 #define off_t long
58 #define uint UINT
59 #endif /* WIN32 */
60 
61 #ifdef HAVE_SMI_H
62 #include <smi.h>
63 #endif
64 
65 #include <pcap.h>
66 #include <signal.h>
67 #include <stdio.h>
68 #include <stdlib.h>
69 #include <string.h>
70 #include <limits.h>
71 #ifdef __FreeBSD__
72 #include <sys/capability.h>
73 #include <sys/ioccom.h>
74 #include <net/bpf.h>
75 #include <fcntl.h>
76 #include <libgen.h>
77 #endif	/* __FreeBSD__ */
78 #ifndef WIN32
79 #include <sys/wait.h>
80 #include <sys/resource.h>
81 #include <pwd.h>
82 #include <grp.h>
83 #include <errno.h>
84 #endif /* WIN32 */
85 
86 /* capabilities convinience library */
87 #ifdef HAVE_CAP_NG_H
88 #include <cap-ng.h>
89 #endif /* HAVE_CAP_NG_H */
90 
91 #include "netdissect.h"
92 #include "interface.h"
93 #include "addrtoname.h"
94 #include "machdep.h"
95 #include "setsignal.h"
96 #include "gmt2local.h"
97 #include "pcap-missing.h"
98 
99 #ifndef PATH_MAX
100 #define PATH_MAX 1024
101 #endif
102 
103 #ifdef SIGINFO
104 #define SIGNAL_REQ_INFO SIGINFO
105 #elif SIGUSR1
106 #define SIGNAL_REQ_INFO SIGUSR1
107 #endif
108 
109 netdissect_options Gndo;
110 netdissect_options *gndo = &Gndo;
111 
112 static int dflag;			/* print filter code */
113 static int Lflag;			/* list available data link types and exit */
114 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
115 static int Jflag;			/* list available time stamp types */
116 #endif
117 static char *zflag = NULL;		/* compress each savefile using a specified command (like gzip or bzip2) */
118 
119 static int infodelay;
120 static int infoprint;
121 
122 char *program_name;
123 
124 int32_t thiszone;		/* seconds offset from gmt to local time */
125 
126 /* Forwards */
127 static RETSIGTYPE cleanup(int);
128 static RETSIGTYPE child_cleanup(int);
129 static void usage(void) __attribute__((noreturn));
130 static void show_dlts_and_exit(const char *device, pcap_t *pd) __attribute__((noreturn));
131 
132 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
133 static void ndo_default_print(netdissect_options *, const u_char *, u_int);
134 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
135 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
136 static void droproot(const char *, const char *);
137 static void ndo_error(netdissect_options *ndo, const char *fmt, ...)
138      __attribute__ ((noreturn, format (printf, 2, 3)));
139 static void ndo_warning(netdissect_options *ndo, const char *fmt, ...);
140 
141 #ifdef SIGNAL_REQ_INFO
142 RETSIGTYPE requestinfo(int);
143 #endif
144 
145 #if defined(USE_WIN32_MM_TIMER)
146   #include <MMsystem.h>
147   static UINT timer_id;
148   static void CALLBACK verbose_stats_dump(UINT, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR);
149 #elif defined(HAVE_ALARM)
150   static void verbose_stats_dump(int sig);
151 #endif
152 
153 static void info(int);
154 static u_int packets_captured;
155 
156 struct printer {
157         if_printer f;
158 	int type;
159 };
160 
161 
162 struct ndo_printer {
163         if_ndo_printer f;
164 	int type;
165 };
166 
167 
168 static struct printer printers[] = {
169 	{ arcnet_if_print,	DLT_ARCNET },
170 #ifdef DLT_ARCNET_LINUX
171 	{ arcnet_linux_if_print, DLT_ARCNET_LINUX },
172 #endif
173 	{ token_if_print,	DLT_IEEE802 },
174 #ifdef DLT_LANE8023
175 	{ lane_if_print,        DLT_LANE8023 },
176 #endif
177 #ifdef DLT_CIP
178 	{ cip_if_print,         DLT_CIP },
179 #endif
180 #ifdef DLT_ATM_CLIP
181 	{ cip_if_print,		DLT_ATM_CLIP },
182 #endif
183 	{ sl_if_print,		DLT_SLIP },
184 #ifdef DLT_SLIP_BSDOS
185 	{ sl_bsdos_if_print,	DLT_SLIP_BSDOS },
186 #endif
187 	{ ppp_if_print,		DLT_PPP },
188 #ifdef DLT_PPP_WITHDIRECTION
189 	{ ppp_if_print,		DLT_PPP_WITHDIRECTION },
190 #endif
191 #ifdef DLT_PPP_BSDOS
192 	{ ppp_bsdos_if_print,	DLT_PPP_BSDOS },
193 #endif
194 	{ fddi_if_print,	DLT_FDDI },
195 	{ null_if_print,	DLT_NULL },
196 #ifdef DLT_LOOP
197 	{ null_if_print,	DLT_LOOP },
198 #endif
199 	{ raw_if_print,		DLT_RAW },
200 	{ atm_if_print,		DLT_ATM_RFC1483 },
201 #ifdef DLT_C_HDLC
202 	{ chdlc_if_print,	DLT_C_HDLC },
203 #endif
204 #ifdef DLT_HDLC
205 	{ chdlc_if_print,	DLT_HDLC },
206 #endif
207 #ifdef DLT_PPP_SERIAL
208 	{ ppp_hdlc_if_print,	DLT_PPP_SERIAL },
209 #endif
210 #ifdef DLT_PPP_ETHER
211 	{ pppoe_if_print,	DLT_PPP_ETHER },
212 #endif
213 #ifdef DLT_LINUX_SLL
214 	{ sll_if_print,		DLT_LINUX_SLL },
215 #endif
216 #ifdef DLT_IEEE802_11
217 	{ ieee802_11_if_print,	DLT_IEEE802_11},
218 #endif
219 #ifdef DLT_LTALK
220 	{ ltalk_if_print,	DLT_LTALK },
221 #endif
222 #if defined(DLT_PFLOG) && defined(HAVE_NET_PFVAR_H)
223 	{ pflog_if_print,	DLT_PFLOG },
224 #endif
225 #ifdef DLT_FR
226 	{ fr_if_print,		DLT_FR },
227 #endif
228 #ifdef DLT_FRELAY
229 	{ fr_if_print,		DLT_FRELAY },
230 #endif
231 #ifdef DLT_SUNATM
232 	{ sunatm_if_print,	DLT_SUNATM },
233 #endif
234 #ifdef DLT_IP_OVER_FC
235 	{ ipfc_if_print,	DLT_IP_OVER_FC },
236 #endif
237 #ifdef DLT_PRISM_HEADER
238 	{ prism_if_print,	DLT_PRISM_HEADER },
239 #endif
240 #ifdef DLT_IEEE802_11_RADIO
241 	{ ieee802_11_radio_if_print,	DLT_IEEE802_11_RADIO },
242 #endif
243 #ifdef DLT_ENC
244 	{ enc_if_print,		DLT_ENC },
245 #endif
246 #ifdef DLT_SYMANTEC_FIREWALL
247 	{ symantec_if_print,	DLT_SYMANTEC_FIREWALL },
248 #endif
249 #ifdef DLT_APPLE_IP_OVER_IEEE1394
250 	{ ap1394_if_print,	DLT_APPLE_IP_OVER_IEEE1394 },
251 #endif
252 #ifdef DLT_IEEE802_11_RADIO_AVS
253 	{ ieee802_11_radio_avs_if_print,	DLT_IEEE802_11_RADIO_AVS },
254 #endif
255 #ifdef DLT_JUNIPER_ATM1
256 	{ juniper_atm1_print,	DLT_JUNIPER_ATM1 },
257 #endif
258 #ifdef DLT_JUNIPER_ATM2
259 	{ juniper_atm2_print,	DLT_JUNIPER_ATM2 },
260 #endif
261 #ifdef DLT_JUNIPER_MFR
262 	{ juniper_mfr_print,	DLT_JUNIPER_MFR },
263 #endif
264 #ifdef DLT_JUNIPER_MLFR
265 	{ juniper_mlfr_print,	DLT_JUNIPER_MLFR },
266 #endif
267 #ifdef DLT_JUNIPER_MLPPP
268 	{ juniper_mlppp_print,	DLT_JUNIPER_MLPPP },
269 #endif
270 #ifdef DLT_JUNIPER_PPPOE
271 	{ juniper_pppoe_print,	DLT_JUNIPER_PPPOE },
272 #endif
273 #ifdef DLT_JUNIPER_PPPOE_ATM
274 	{ juniper_pppoe_atm_print, DLT_JUNIPER_PPPOE_ATM },
275 #endif
276 #ifdef DLT_JUNIPER_GGSN
277 	{ juniper_ggsn_print,	DLT_JUNIPER_GGSN },
278 #endif
279 #ifdef DLT_JUNIPER_ES
280 	{ juniper_es_print,	DLT_JUNIPER_ES },
281 #endif
282 #ifdef DLT_JUNIPER_MONITOR
283 	{ juniper_monitor_print, DLT_JUNIPER_MONITOR },
284 #endif
285 #ifdef DLT_JUNIPER_SERVICES
286 	{ juniper_services_print, DLT_JUNIPER_SERVICES },
287 #endif
288 #ifdef DLT_JUNIPER_ETHER
289 	{ juniper_ether_print,	DLT_JUNIPER_ETHER },
290 #endif
291 #ifdef DLT_JUNIPER_PPP
292 	{ juniper_ppp_print,	DLT_JUNIPER_PPP },
293 #endif
294 #ifdef DLT_JUNIPER_FRELAY
295 	{ juniper_frelay_print,	DLT_JUNIPER_FRELAY },
296 #endif
297 #ifdef DLT_JUNIPER_CHDLC
298 	{ juniper_chdlc_print,	DLT_JUNIPER_CHDLC },
299 #endif
300 #ifdef DLT_MFR
301 	{ mfr_if_print,		DLT_MFR },
302 #endif
303 #if defined(DLT_BLUETOOTH_HCI_H4_WITH_PHDR) && defined(HAVE_PCAP_BLUETOOTH_H)
304 	{ bt_if_print,		DLT_BLUETOOTH_HCI_H4_WITH_PHDR},
305 #endif
306 #ifdef HAVE_PCAP_USB_H
307 #ifdef DLT_USB_LINUX
308 	{ usb_linux_48_byte_print, DLT_USB_LINUX},
309 #endif /* DLT_USB_LINUX */
310 #ifdef DLT_USB_LINUX_MMAPPED
311 	{ usb_linux_64_byte_print, DLT_USB_LINUX_MMAPPED},
312 #endif /* DLT_USB_LINUX_MMAPPED */
313 #endif /* HAVE_PCAP_USB_H */
314 #ifdef DLT_IPV4
315 	{ raw_if_print,		DLT_IPV4 },
316 #endif
317 #ifdef DLT_IPV6
318 	{ raw_if_print,		DLT_IPV6 },
319 #endif
320 	{ NULL,			0 },
321 };
322 
323 static struct ndo_printer ndo_printers[] = {
324 	{ ether_if_print,	DLT_EN10MB },
325 #ifdef DLT_IPNET
326 	{ ipnet_if_print,	DLT_IPNET },
327 #endif
328 #ifdef DLT_IEEE802_15_4
329 	{ ieee802_15_4_if_print, DLT_IEEE802_15_4 },
330 #endif
331 #ifdef DLT_IEEE802_15_4_NOFCS
332 	{ ieee802_15_4_if_print, DLT_IEEE802_15_4_NOFCS },
333 #endif
334 #ifdef DLT_PPI
335 	{ ppi_if_print,		DLT_PPI },
336 #endif
337 #ifdef DLT_NETANALYZER
338 	{ netanalyzer_if_print, DLT_NETANALYZER },
339 #endif
340 #ifdef DLT_NETANALYZER_TRANSPARENT
341 	{ netanalyzer_transparent_if_print, DLT_NETANALYZER_TRANSPARENT },
342 #endif
343 	{ NULL,			0 },
344 };
345 
346 if_printer
347 lookup_printer(int type)
348 {
349 	struct printer *p;
350 
351 	for (p = printers; p->f; ++p)
352 		if (type == p->type)
353 			return p->f;
354 
355 	return NULL;
356 	/* NOTREACHED */
357 }
358 
359 if_ndo_printer
360 lookup_ndo_printer(int type)
361 {
362 	struct ndo_printer *p;
363 
364 	for (p = ndo_printers; p->f; ++p)
365 		if (type == p->type)
366 			return p->f;
367 
368 	return NULL;
369 	/* NOTREACHED */
370 }
371 
372 static pcap_t *pd;
373 
374 static int supports_monitor_mode;
375 
376 extern int optind;
377 extern int opterr;
378 extern char *optarg;
379 
380 struct print_info {
381         netdissect_options *ndo;
382         union {
383                 if_printer     printer;
384                 if_ndo_printer ndo_printer;
385         } p;
386         int ndo_type;
387 };
388 
389 struct dump_info {
390 	char	*WFileName;
391 	char	*CurrentFileName;
392 	pcap_t	*pd;
393 	pcap_dumper_t *p;
394 #ifdef __FreeBSD__
395 	int	dirfd;
396 #endif
397 };
398 
399 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
400 static void
401 show_tstamp_types_and_exit(const char *device, pcap_t *pd)
402 {
403 	int n_tstamp_types;
404 	int *tstamp_types = 0;
405 	const char *tstamp_type_name;
406 	int i;
407 
408 	n_tstamp_types = pcap_list_tstamp_types(pd, &tstamp_types);
409 	if (n_tstamp_types < 0)
410 		error("%s", pcap_geterr(pd));
411 
412 	if (n_tstamp_types == 0) {
413 		fprintf(stderr, "Time stamp type cannot be set for %s\n",
414 		    device);
415 		exit(0);
416 	}
417 	fprintf(stderr, "Time stamp types for %s (use option -j to set):\n",
418 	    device);
419 	for (i = 0; i < n_tstamp_types; i++) {
420 		tstamp_type_name = pcap_tstamp_type_val_to_name(tstamp_types[i]);
421 		if (tstamp_type_name != NULL) {
422 			(void) fprintf(stderr, "  %s (%s)\n", tstamp_type_name,
423 			    pcap_tstamp_type_val_to_description(tstamp_types[i]));
424 		} else {
425 			(void) fprintf(stderr, "  %d\n", tstamp_types[i]);
426 		}
427 	}
428 	pcap_free_tstamp_types(tstamp_types);
429 	exit(0);
430 }
431 #endif
432 
433 static void
434 show_dlts_and_exit(const char *device, pcap_t *pd)
435 {
436 	int n_dlts;
437 	int *dlts = 0;
438 	const char *dlt_name;
439 
440 	n_dlts = pcap_list_datalinks(pd, &dlts);
441 	if (n_dlts < 0)
442 		error("%s", pcap_geterr(pd));
443 	else if (n_dlts == 0 || !dlts)
444 		error("No data link types.");
445 
446 	/*
447 	 * If the interface is known to support monitor mode, indicate
448 	 * whether these are the data link types available when not in
449 	 * monitor mode, if -I wasn't specified, or when in monitor mode,
450 	 * when -I was specified (the link-layer types available in
451 	 * monitor mode might be different from the ones available when
452 	 * not in monitor mode).
453 	 */
454 	if (supports_monitor_mode)
455 		(void) fprintf(stderr, "Data link types for %s %s (use option -y to set):\n",
456 		    device,
457 		    Iflag ? "when in monitor mode" : "when not in monitor mode");
458 	else
459 		(void) fprintf(stderr, "Data link types for %s (use option -y to set):\n",
460 		    device);
461 
462 	while (--n_dlts >= 0) {
463 		dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
464 		if (dlt_name != NULL) {
465 			(void) fprintf(stderr, "  %s (%s)", dlt_name,
466 			    pcap_datalink_val_to_description(dlts[n_dlts]));
467 
468 			/*
469 			 * OK, does tcpdump handle that type?
470 			 */
471 			if (lookup_printer(dlts[n_dlts]) == NULL
472                             && lookup_ndo_printer(dlts[n_dlts]) == NULL)
473 				(void) fprintf(stderr, " (printing not supported)");
474 			fprintf(stderr, "\n");
475 		} else {
476 			(void) fprintf(stderr, "  DLT %d (printing not supported)\n",
477 			    dlts[n_dlts]);
478 		}
479 	}
480 #ifdef HAVE_PCAP_FREE_DATALINKS
481 	pcap_free_datalinks(dlts);
482 #endif
483 	exit(0);
484 }
485 
486 /*
487  * Set up flags that might or might not be supported depending on the
488  * version of libpcap we're using.
489  */
490 #if defined(HAVE_PCAP_CREATE) || defined(WIN32)
491 #define B_FLAG		"B:"
492 #define B_FLAG_USAGE	" [ -B size ]"
493 #else /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */
494 #define B_FLAG
495 #define B_FLAG_USAGE
496 #endif /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */
497 
498 #ifdef HAVE_PCAP_CREATE
499 #define I_FLAG		"I"
500 #else /* HAVE_PCAP_CREATE */
501 #define I_FLAG
502 #endif /* HAVE_PCAP_CREATE */
503 
504 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
505 #define j_FLAG		"j:"
506 #define j_FLAG_USAGE	" [ -j tstamptype ]"
507 #define J_FLAG		"J"
508 #else /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
509 #define j_FLAG
510 #define j_FLAG_USAGE
511 #define J_FLAG
512 #endif /* PCAP_ERROR_TSTAMP_TYPE_NOTSUP */
513 
514 #ifdef HAVE_PCAP_FINDALLDEVS
515 #ifndef HAVE_PCAP_IF_T
516 #undef HAVE_PCAP_FINDALLDEVS
517 #endif
518 #endif
519 
520 #ifdef HAVE_PCAP_FINDALLDEVS
521 #define D_FLAG	"D"
522 #else
523 #define D_FLAG
524 #endif
525 
526 #ifdef HAVE_PCAP_DUMP_FLUSH
527 #define U_FLAG	"U"
528 #else
529 #define U_FLAG
530 #endif
531 
532 #ifndef WIN32
533 /* Drop root privileges and chroot if necessary */
534 static void
535 droproot(const char *username, const char *chroot_dir)
536 {
537 	struct passwd *pw = NULL;
538 
539 	if (chroot_dir && !username) {
540 		fprintf(stderr, "tcpdump: Chroot without dropping root is insecure\n");
541 		exit(1);
542 	}
543 
544 	pw = getpwnam(username);
545 	if (pw) {
546 		if (chroot_dir) {
547 			if (chroot(chroot_dir) != 0 || chdir ("/") != 0) {
548 				fprintf(stderr, "tcpdump: Couldn't chroot/chdir to '%.64s': %s\n",
549 				    chroot_dir, pcap_strerror(errno));
550 				exit(1);
551 			}
552 		}
553 #ifdef HAVE_CAP_NG_H
554 		int ret = capng_change_id(pw->pw_uid, pw->pw_gid, CAPNG_NO_FLAG);
555 		if (ret < 0) {
556 			printf("error : ret %d\n", ret);
557 		}
558 		/* We don't need CAP_SETUID and CAP_SETGID */
559 		capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_SETUID);
560 		capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_SETUID);
561 		capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_SETUID);
562 		capng_update(CAPNG_DROP, CAPNG_PERMITTED, CAP_SETUID);
563 		capng_apply(CAPNG_SELECT_BOTH);
564 
565 #else
566 		if (initgroups(pw->pw_name, pw->pw_gid) != 0 ||
567 		    setgid(pw->pw_gid) != 0 || setuid(pw->pw_uid) != 0) {
568 			fprintf(stderr, "tcpdump: Couldn't change to '%.32s' uid=%lu gid=%lu: %s\n",
569 			    username,
570 			    (unsigned long)pw->pw_uid,
571 			    (unsigned long)pw->pw_gid,
572 			    pcap_strerror(errno));
573 			exit(1);
574 		}
575 #endif /* HAVE_CAP_NG_H */
576 	}
577 	else {
578 		fprintf(stderr, "tcpdump: Couldn't find user '%.32s'\n",
579 		    username);
580 		exit(1);
581 	}
582 }
583 #endif /* WIN32 */
584 
585 static int
586 getWflagChars(int x)
587 {
588 	int c = 0;
589 
590 	x -= 1;
591 	while (x > 0) {
592 		c += 1;
593 		x /= 10;
594 	}
595 
596 	return c;
597 }
598 
599 
600 static void
601 MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
602 {
603         char *filename = malloc(PATH_MAX + 1);
604         if (filename == NULL)
605             error("Makefilename: malloc");
606 
607         /* Process with strftime if Gflag is set. */
608         if (Gflag != 0) {
609           struct tm *local_tm;
610 
611           /* Convert Gflag_time to a usable format */
612           if ((local_tm = localtime(&Gflag_time)) == NULL) {
613                   error("MakeTimedFilename: localtime");
614           }
615 
616           /* There's no good way to detect an error in strftime since a return
617            * value of 0 isn't necessarily failure.
618            */
619           strftime(filename, PATH_MAX, orig_name, local_tm);
620         } else {
621           strncpy(filename, orig_name, PATH_MAX);
622         }
623 
624 	if (cnt == 0 && max_chars == 0)
625 		strncpy(buffer, filename, PATH_MAX + 1);
626 	else
627 		if (snprintf(buffer, PATH_MAX + 1, "%s%0*d", filename, max_chars, cnt) > PATH_MAX)
628                   /* Report an error if the filename is too large */
629                   error("too many output files or filename is too long (> %d)", PATH_MAX);
630         free(filename);
631 }
632 
633 static int tcpdump_printf(netdissect_options *ndo _U_,
634 			  const char *fmt, ...)
635 {
636 
637   va_list args;
638   int ret;
639 
640   va_start(args, fmt);
641   ret=vfprintf(stdout, fmt, args);
642   va_end(args);
643 
644   return ret;
645 }
646 
647 static struct print_info
648 get_print_info(int type)
649 {
650 	struct print_info printinfo;
651 
652 	printinfo.ndo_type = 1;
653 	printinfo.ndo = gndo;
654 	printinfo.p.ndo_printer = lookup_ndo_printer(type);
655 	if (printinfo.p.ndo_printer == NULL) {
656 		printinfo.p.printer = lookup_printer(type);
657 		printinfo.ndo_type = 0;
658 		if (printinfo.p.printer == NULL) {
659 			gndo->ndo_dltname = pcap_datalink_val_to_name(type);
660 			if (gndo->ndo_dltname != NULL)
661 				error("packet printing is not supported for link type %s: use -w",
662 				      gndo->ndo_dltname);
663 			else
664 				error("packet printing is not supported for link type %d: use -w", type);
665 		}
666 	}
667 	return (printinfo);
668 }
669 
670 static char *
671 get_next_file(FILE *VFile, char *ptr)
672 {
673 	char *ret;
674 
675 	ret = fgets(ptr, PATH_MAX, VFile);
676 	if (!ret)
677 		return NULL;
678 
679 	if (ptr[strlen(ptr) - 1] == '\n')
680 		ptr[strlen(ptr) - 1] = '\0';
681 
682 	return ret;
683 }
684 
685 int
686 main(int argc, char **argv)
687 {
688 	register int cnt, op, i;
689 	bpf_u_int32 localnet, netmask;
690 	register char *cp, *infile, *cmdbuf, *device, *RFileName, *VFileName, *WFileName;
691 	pcap_handler callback;
692 	int type;
693 	int dlt;
694 	int new_dlt;
695 	const char *dlt_name;
696 	struct bpf_program fcode;
697 #ifndef WIN32
698 	RETSIGTYPE (*oldhandler)(int);
699 #endif
700 	struct print_info printinfo;
701 	struct dump_info dumpinfo;
702 	u_char *pcap_userdata;
703 	char ebuf[PCAP_ERRBUF_SIZE];
704 	char VFileLine[PATH_MAX + 1];
705 	char *username = NULL;
706 	char *chroot_dir = NULL;
707 	char *ret = NULL;
708 	char *end;
709 #ifdef HAVE_PCAP_FINDALLDEVS
710 	pcap_if_t *devpointer;
711 	int devnum;
712 #endif
713 	int status;
714 	FILE *VFile;
715 #ifdef __FreeBSD__
716 	int cansandbox;
717 #endif
718 
719 #ifdef WIN32
720 	if(wsockinit() != 0) return 1;
721 #endif /* WIN32 */
722 
723 	jflag=-1;	/* not set */
724         gndo->ndo_Oflag=1;
725 	gndo->ndo_Rflag=1;
726 	gndo->ndo_dlt=-1;
727 	gndo->ndo_default_print=ndo_default_print;
728 	gndo->ndo_printf=tcpdump_printf;
729 	gndo->ndo_error=ndo_error;
730 	gndo->ndo_warning=ndo_warning;
731 	gndo->ndo_snaplen = DEFAULT_SNAPLEN;
732 
733 	cnt = -1;
734 	device = NULL;
735 	infile = NULL;
736 	RFileName = NULL;
737 	VFileName = NULL;
738 	VFile = NULL;
739 	WFileName = NULL;
740 	dlt = -1;
741 	if ((cp = strrchr(argv[0], '/')) != NULL)
742 		program_name = cp + 1;
743 	else
744 		program_name = argv[0];
745 
746 	if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
747 		error("%s", ebuf);
748 
749 #ifdef LIBSMI
750 	smiInit("tcpdump");
751 #endif
752 
753 	while (
754 	    (op = getopt(argc, argv, "aAb" B_FLAG "c:C:d" D_FLAG "eE:fF:G:hHi:" I_FLAG j_FLAG J_FLAG "KlLm:M:nNOpqr:Rs:StT:u" U_FLAG "V:vw:W:xXy:Yz:Z:")) != -1)
755 		switch (op) {
756 
757 		case 'a':
758 			/* compatibility for old -a */
759 			break;
760 
761 		case 'A':
762 			++Aflag;
763 			break;
764 
765 		case 'b':
766 			++bflag;
767 			break;
768 
769 #if defined(HAVE_PCAP_CREATE) || defined(WIN32)
770 		case 'B':
771 			Bflag = atoi(optarg)*1024;
772 			if (Bflag <= 0)
773 				error("invalid packet buffer size %s", optarg);
774 			break;
775 #endif /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */
776 
777 		case 'c':
778 			cnt = atoi(optarg);
779 			if (cnt <= 0)
780 				error("invalid packet count %s", optarg);
781 			break;
782 
783 		case 'C':
784 			Cflag = atoi(optarg) * 1000000;
785 			if (Cflag < 0)
786 				error("invalid file size %s", optarg);
787 			break;
788 
789 		case 'd':
790 			++dflag;
791 			break;
792 
793 #ifdef HAVE_PCAP_FINDALLDEVS
794 		case 'D':
795 			if (pcap_findalldevs(&devpointer, ebuf) < 0)
796 				error("%s", ebuf);
797 			else {
798 				for (i = 0; devpointer != 0; i++) {
799 					printf("%d.%s", i+1, devpointer->name);
800 					if (devpointer->description != NULL)
801 						printf(" (%s)", devpointer->description);
802 					printf("\n");
803 					devpointer = devpointer->next;
804 				}
805 			}
806 			return 0;
807 #endif /* HAVE_PCAP_FINDALLDEVS */
808 
809 		case 'L':
810 			Lflag++;
811 			break;
812 
813 		case 'e':
814 			++eflag;
815 			break;
816 
817 		case 'E':
818 #ifndef HAVE_LIBCRYPTO
819 			warning("crypto code not compiled in");
820 #endif
821 			gndo->ndo_espsecret = optarg;
822 			break;
823 
824 		case 'f':
825 			++fflag;
826 			break;
827 
828 		case 'F':
829 			infile = optarg;
830 			break;
831 
832 		case 'G':
833 			Gflag = atoi(optarg);
834 			if (Gflag < 0)
835 				error("invalid number of seconds %s", optarg);
836 
837                         /* We will create one file initially. */
838                         Gflag_count = 0;
839 
840 			/* Grab the current time for rotation use. */
841 			if ((Gflag_time = time(NULL)) == (time_t)-1) {
842 				error("main: can't get current time: %s",
843 				    pcap_strerror(errno));
844 			}
845 			break;
846 
847 		case 'h':
848 			usage();
849 			break;
850 
851 		case 'H':
852 			++Hflag;
853 			break;
854 
855 		case 'i':
856 			if (optarg[0] == '0' && optarg[1] == 0)
857 				error("Invalid adapter index");
858 
859 #ifdef HAVE_PCAP_FINDALLDEVS
860 			/*
861 			 * If the argument is a number, treat it as
862 			 * an index into the list of adapters, as
863 			 * printed by "tcpdump -D".
864 			 *
865 			 * This should be OK on UNIX systems, as interfaces
866 			 * shouldn't have names that begin with digits.
867 			 * It can be useful on Windows, where more than
868 			 * one interface can have the same name.
869 			 */
870 			devnum = strtol(optarg, &end, 10);
871 			if (optarg != end && *end == '\0') {
872 				if (devnum < 0)
873 					error("Invalid adapter index");
874 
875 				if (pcap_findalldevs(&devpointer, ebuf) < 0)
876 					error("%s", ebuf);
877 				else {
878 					/*
879 					 * Look for the devnum-th entry
880 					 * in the list of devices
881 					 * (1-based).
882 					 */
883 					for (i = 0;
884 					    i < devnum-1 && devpointer != NULL;
885 					    i++, devpointer = devpointer->next)
886 						;
887 					if (devpointer == NULL)
888 						error("Invalid adapter index");
889 				}
890 				device = devpointer->name;
891 				break;
892 			}
893 #endif /* HAVE_PCAP_FINDALLDEVS */
894 			device = optarg;
895 			break;
896 
897 #ifdef HAVE_PCAP_CREATE
898 		case 'I':
899 			++Iflag;
900 			break;
901 #endif /* HAVE_PCAP_CREATE */
902 
903 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
904 		case 'j':
905 			jflag = pcap_tstamp_type_name_to_val(optarg);
906 			if (jflag < 0)
907 				error("invalid time stamp type %s", optarg);
908 			break;
909 
910 		case 'J':
911 			Jflag++;
912 			break;
913 #endif
914 
915 		case 'l':
916 #ifdef WIN32
917 			/*
918 			 * _IOLBF is the same as _IOFBF in Microsoft's C
919 			 * libraries; the only alternative they offer
920 			 * is _IONBF.
921 			 *
922 			 * XXX - this should really be checking for MSVC++,
923 			 * not WIN32, if, for example, MinGW has its own
924 			 * C library that is more UNIX-compatible.
925 			 */
926 			setvbuf(stdout, NULL, _IONBF, 0);
927 #else /* WIN32 */
928 #ifdef HAVE_SETLINEBUF
929 			setlinebuf(stdout);
930 #else
931 			setvbuf(stdout, NULL, _IOLBF, 0);
932 #endif
933 #endif /* WIN32 */
934 			break;
935 
936 		case 'K':
937 			++Kflag;
938 			break;
939 
940 		case 'm':
941 #ifdef LIBSMI
942 			if (smiLoadModule(optarg) == 0) {
943 				error("could not load MIB module %s", optarg);
944 			}
945 			sflag = 1;
946 #else
947 			(void)fprintf(stderr, "%s: ignoring option `-m %s' ",
948 				      program_name, optarg);
949 			(void)fprintf(stderr, "(no libsmi support)\n");
950 #endif
951 			break;
952 
953 		case 'M':
954 			/* TCP-MD5 shared secret */
955 #ifndef HAVE_LIBCRYPTO
956 			warning("crypto code not compiled in");
957 #endif
958 			sigsecret = optarg;
959 			break;
960 
961 		case 'n':
962 			++nflag;
963 			break;
964 
965 		case 'N':
966 			++Nflag;
967 			break;
968 
969 		case 'O':
970 			Oflag = 0;
971 			break;
972 
973 		case 'p':
974 			++pflag;
975 			break;
976 
977 		case 'q':
978 			++qflag;
979 			++suppress_default_print;
980 			break;
981 
982 		case 'r':
983 			RFileName = optarg;
984 			break;
985 
986 		case 'R':
987 			Rflag = 0;
988 			break;
989 
990 		case 's':
991 			snaplen = strtol(optarg, &end, 0);
992 			if (optarg == end || *end != '\0'
993 			    || snaplen < 0 || snaplen > MAXIMUM_SNAPLEN)
994 				error("invalid snaplen %s", optarg);
995 			else if (snaplen == 0)
996 				snaplen = MAXIMUM_SNAPLEN;
997 			break;
998 
999 		case 'S':
1000 			++Sflag;
1001 			break;
1002 
1003 		case 't':
1004 			++tflag;
1005 			break;
1006 
1007 		case 'T':
1008 			if (strcasecmp(optarg, "vat") == 0)
1009 				packettype = PT_VAT;
1010 			else if (strcasecmp(optarg, "wb") == 0)
1011 				packettype = PT_WB;
1012 			else if (strcasecmp(optarg, "rpc") == 0)
1013 				packettype = PT_RPC;
1014 			else if (strcasecmp(optarg, "rtp") == 0)
1015 				packettype = PT_RTP;
1016 			else if (strcasecmp(optarg, "rtcp") == 0)
1017 				packettype = PT_RTCP;
1018 			else if (strcasecmp(optarg, "snmp") == 0)
1019 				packettype = PT_SNMP;
1020 			else if (strcasecmp(optarg, "cnfp") == 0)
1021 				packettype = PT_CNFP;
1022 			else if (strcasecmp(optarg, "tftp") == 0)
1023 				packettype = PT_TFTP;
1024 			else if (strcasecmp(optarg, "aodv") == 0)
1025 				packettype = PT_AODV;
1026 			else if (strcasecmp(optarg, "carp") == 0)
1027 				packettype = PT_CARP;
1028 			else if (strcasecmp(optarg, "radius") == 0)
1029 				packettype = PT_RADIUS;
1030 			else if (strcasecmp(optarg, "zmtp1") == 0)
1031 				packettype = PT_ZMTP1;
1032 			else if (strcasecmp(optarg, "vxlan") == 0)
1033 				packettype = PT_VXLAN;
1034 			else
1035 				error("unknown packet type `%s'", optarg);
1036 			break;
1037 
1038 		case 'u':
1039 			++uflag;
1040 			break;
1041 
1042 #ifdef HAVE_PCAP_DUMP_FLUSH
1043 		case 'U':
1044 			++Uflag;
1045 			break;
1046 #endif
1047 
1048 		case 'v':
1049 			++vflag;
1050 			break;
1051 
1052 		case 'V':
1053 			VFileName = optarg;
1054 			break;
1055 
1056 		case 'w':
1057 			WFileName = optarg;
1058 			break;
1059 
1060 		case 'W':
1061 			Wflag = atoi(optarg);
1062 			if (Wflag < 0)
1063 				error("invalid number of output files %s", optarg);
1064 			WflagChars = getWflagChars(Wflag);
1065 			break;
1066 
1067 		case 'x':
1068 			++xflag;
1069 			++suppress_default_print;
1070 			break;
1071 
1072 		case 'X':
1073 			++Xflag;
1074 			++suppress_default_print;
1075 			break;
1076 
1077 		case 'y':
1078 			gndo->ndo_dltname = optarg;
1079 			gndo->ndo_dlt =
1080 			  pcap_datalink_name_to_val(gndo->ndo_dltname);
1081 			if (gndo->ndo_dlt < 0)
1082 				error("invalid data link type %s", gndo->ndo_dltname);
1083 			break;
1084 
1085 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
1086 		case 'Y':
1087 			{
1088 			/* Undocumented flag */
1089 #ifdef HAVE_PCAP_DEBUG
1090 			extern int pcap_debug;
1091 			pcap_debug = 1;
1092 #else
1093 			extern int yydebug;
1094 			yydebug = 1;
1095 #endif
1096 			}
1097 			break;
1098 #endif
1099 		case 'z':
1100 			if (optarg) {
1101 				zflag = strdup(optarg);
1102 			} else {
1103 				usage();
1104 				/* NOTREACHED */
1105 			}
1106 			break;
1107 
1108 		case 'Z':
1109 			if (optarg) {
1110 				username = strdup(optarg);
1111 			}
1112 			else {
1113 				usage();
1114 				/* NOTREACHED */
1115 			}
1116 			break;
1117 
1118 		default:
1119 			usage();
1120 			/* NOTREACHED */
1121 		}
1122 
1123 	switch (tflag) {
1124 
1125 	case 0: /* Default */
1126 	case 4: /* Default + Date*/
1127 		thiszone = gmt2local(0);
1128 		break;
1129 
1130 	case 1: /* No time stamp */
1131 	case 2: /* Unix timeval style */
1132 	case 3: /* Microseconds since previous packet */
1133         case 5: /* Microseconds since first packet */
1134 		break;
1135 
1136 	default: /* Not supported */
1137 		error("only -t, -tt, -ttt, -tttt and -ttttt are supported");
1138 		break;
1139 	}
1140 
1141 	if (fflag != 0 && (VFileName != NULL || RFileName != NULL))
1142 		error("-f can not be used with -V or -r");
1143 
1144 	if (VFileName != NULL && RFileName != NULL)
1145 		error("-V and -r are mutually exclusive.");
1146 
1147 #ifdef WITH_CHROOT
1148 	/* if run as root, prepare for chrooting */
1149 	if (getuid() == 0 || geteuid() == 0) {
1150 		/* future extensibility for cmd-line arguments */
1151 		if (!chroot_dir)
1152 			chroot_dir = WITH_CHROOT;
1153 	}
1154 #endif
1155 
1156 #ifdef WITH_USER
1157 	/* if run as root, prepare for dropping root privileges */
1158 	if (getuid() == 0 || geteuid() == 0) {
1159 		/* Run with '-Z root' to restore old behaviour */
1160 		if (!username)
1161 			username = WITH_USER;
1162 	}
1163 #endif
1164 
1165 	if (RFileName != NULL || VFileName != NULL) {
1166 		/*
1167 		 * If RFileName is non-null, it's the pathname of a
1168 		 * savefile to read.  If VFileName is non-null, it's
1169 		 * the pathname of a file containing a list of pathnames
1170 		 * (one per line) of savefiles to read.
1171 		 *
1172 		 * In either case, we're reading a savefile, not doing
1173 		 * a live capture.
1174 		 */
1175 #ifndef WIN32
1176 		/*
1177 		 * We don't need network access, so relinquish any set-UID
1178 		 * or set-GID privileges we have (if any).
1179 		 *
1180 		 * We do *not* want set-UID privileges when opening a
1181 		 * trace file, as that might let the user read other
1182 		 * people's trace files (especially if we're set-UID
1183 		 * root).
1184 		 */
1185 		if (setgid(getgid()) != 0 || setuid(getuid()) != 0 )
1186 			fprintf(stderr, "Warning: setgid/setuid failed !\n");
1187 #endif /* WIN32 */
1188 		if (VFileName != NULL) {
1189 			if (VFileName[0] == '-' && VFileName[1] == '\0')
1190 				VFile = stdin;
1191 			else
1192 				VFile = fopen(VFileName, "r");
1193 
1194 			if (VFile == NULL)
1195 				error("Unable to open file: %s\n", strerror(errno));
1196 
1197 			ret = get_next_file(VFile, VFileLine);
1198 			if (!ret)
1199 				error("Nothing in %s\n", VFileName);
1200 			RFileName = VFileLine;
1201 		}
1202 
1203 		pd = pcap_open_offline(RFileName, ebuf);
1204 		if (pd == NULL)
1205 			error("%s", ebuf);
1206 #ifdef __FreeBSD__
1207 		if (cap_rights_limit(fileno(pcap_file(pd)), CAP_READ) < 0 &&
1208 		    errno != ENOSYS) {
1209 			error("unable to limit pcap descriptor");
1210 		}
1211 #endif
1212 		dlt = pcap_datalink(pd);
1213 		dlt_name = pcap_datalink_val_to_name(dlt);
1214 		if (dlt_name == NULL) {
1215 			fprintf(stderr, "reading from file %s, link-type %u\n",
1216 			    RFileName, dlt);
1217 		} else {
1218 			fprintf(stderr,
1219 			    "reading from file %s, link-type %s (%s)\n",
1220 			    RFileName, dlt_name,
1221 			    pcap_datalink_val_to_description(dlt));
1222 		}
1223 		localnet = 0;
1224 		netmask = 0;
1225 	} else {
1226 		/*
1227 		 * We're doing a live capture.
1228 		 */
1229 		if (device == NULL) {
1230 			device = pcap_lookupdev(ebuf);
1231 			if (device == NULL)
1232 				error("%s", ebuf);
1233 		}
1234 #ifdef WIN32
1235 		/*
1236 		 * Print a message to the standard error on Windows.
1237 		 * XXX - why do it here, with a different message?
1238 		 */
1239 		if(strlen(device) == 1)	//we assume that an ASCII string is always longer than 1 char
1240 		{						//a Unicode string has a \0 as second byte (so strlen() is 1)
1241 			fprintf(stderr, "%s: listening on %ws\n", program_name, device);
1242 		}
1243 		else
1244 		{
1245 			fprintf(stderr, "%s: listening on %s\n", program_name, device);
1246 		}
1247 
1248 		fflush(stderr);
1249 #endif /* WIN32 */
1250 #ifdef HAVE_PCAP_CREATE
1251 		pd = pcap_create(device, ebuf);
1252 		if (pd == NULL)
1253 			error("%s", ebuf);
1254 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
1255 		if (Jflag)
1256 			show_tstamp_types_and_exit(device, pd);
1257 #endif
1258 		/*
1259 		 * Is this an interface that supports monitor mode?
1260 		 */
1261 		if (pcap_can_set_rfmon(pd) == 1)
1262 			supports_monitor_mode = 1;
1263 		else
1264 			supports_monitor_mode = 0;
1265 		status = pcap_set_snaplen(pd, snaplen);
1266 		if (status != 0)
1267 			error("%s: Can't set snapshot length: %s",
1268 			    device, pcap_statustostr(status));
1269 		status = pcap_set_promisc(pd, !pflag);
1270 		if (status != 0)
1271 			error("%s: Can't set promiscuous mode: %s",
1272 			    device, pcap_statustostr(status));
1273 		if (Iflag) {
1274 			status = pcap_set_rfmon(pd, 1);
1275 			if (status != 0)
1276 				error("%s: Can't set monitor mode: %s",
1277 				    device, pcap_statustostr(status));
1278 		}
1279 		status = pcap_set_timeout(pd, 1000);
1280 		if (status != 0)
1281 			error("%s: pcap_set_timeout failed: %s",
1282 			    device, pcap_statustostr(status));
1283 		if (Bflag != 0) {
1284 			status = pcap_set_buffer_size(pd, Bflag);
1285 			if (status != 0)
1286 				error("%s: Can't set buffer size: %s",
1287 				    device, pcap_statustostr(status));
1288 		}
1289 #ifdef HAVE_PCAP_SET_TSTAMP_TYPE
1290                 if (jflag != -1) {
1291 			status = pcap_set_tstamp_type(pd, jflag);
1292 			if (status < 0)
1293 				error("%s: Can't set time stamp type: %s",
1294 			    	    device, pcap_statustostr(status));
1295 		}
1296 #endif
1297 		status = pcap_activate(pd);
1298 		if (status < 0) {
1299 			/*
1300 			 * pcap_activate() failed.
1301 			 */
1302 			cp = pcap_geterr(pd);
1303 			if (status == PCAP_ERROR)
1304 				error("%s", cp);
1305 			else if ((status == PCAP_ERROR_NO_SUCH_DEVICE ||
1306 			          status == PCAP_ERROR_PERM_DENIED) &&
1307 			         *cp != '\0')
1308 				error("%s: %s\n(%s)", device,
1309 				    pcap_statustostr(status), cp);
1310 			else
1311 				error("%s: %s", device,
1312 				    pcap_statustostr(status));
1313 		} else if (status > 0) {
1314 			/*
1315 			 * pcap_activate() succeeded, but it's warning us
1316 			 * of a problem it had.
1317 			 */
1318 			cp = pcap_geterr(pd);
1319 			if (status == PCAP_WARNING)
1320 				warning("%s", cp);
1321 			else if (status == PCAP_WARNING_PROMISC_NOTSUP &&
1322 			         *cp != '\0')
1323 				warning("%s: %s\n(%s)", device,
1324 				    pcap_statustostr(status), cp);
1325 			else
1326 				warning("%s: %s", device,
1327 				    pcap_statustostr(status));
1328 		}
1329 #else
1330 		*ebuf = '\0';
1331 		pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
1332 		if (pd == NULL)
1333 			error("%s", ebuf);
1334 		else if (*ebuf)
1335 			warning("%s", ebuf);
1336 #endif /* HAVE_PCAP_CREATE */
1337 		/*
1338 		 * Let user own process after socket has been opened.
1339 		 */
1340 #ifndef WIN32
1341 		if (setgid(getgid()) != 0 || setuid(getuid()) != 0)
1342 			fprintf(stderr, "Warning: setgid/setuid failed !\n");
1343 #endif /* WIN32 */
1344 #if !defined(HAVE_PCAP_CREATE) && defined(WIN32)
1345 		if(Bflag != 0)
1346 			if(pcap_setbuff(pd, Bflag)==-1){
1347 				error("%s", pcap_geterr(pd));
1348 			}
1349 #endif /* !defined(HAVE_PCAP_CREATE) && defined(WIN32) */
1350 		if (Lflag)
1351 			show_dlts_and_exit(device, pd);
1352 		if (gndo->ndo_dlt >= 0) {
1353 #ifdef HAVE_PCAP_SET_DATALINK
1354 			if (pcap_set_datalink(pd, gndo->ndo_dlt) < 0)
1355 				error("%s", pcap_geterr(pd));
1356 #else
1357 			/*
1358 			 * We don't actually support changing the
1359 			 * data link type, so we only let them
1360 			 * set it to what it already is.
1361 			 */
1362 			if (gndo->ndo_dlt != pcap_datalink(pd)) {
1363 				error("%s is not one of the DLTs supported by this device\n",
1364 				      gndo->ndo_dltname);
1365 			}
1366 #endif
1367 			(void)fprintf(stderr, "%s: data link type %s\n",
1368 				      program_name, gndo->ndo_dltname);
1369 			(void)fflush(stderr);
1370 		}
1371 		i = pcap_snapshot(pd);
1372 		if (snaplen < i) {
1373 			warning("snaplen raised from %d to %d", snaplen, i);
1374 			snaplen = i;
1375 		}
1376 		if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
1377 			localnet = 0;
1378 			netmask = 0;
1379 			warning("%s", ebuf);
1380 		}
1381 	}
1382 	if (infile)
1383 		cmdbuf = read_infile(infile);
1384 	else
1385 		cmdbuf = copy_argv(&argv[optind]);
1386 
1387 	if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
1388 		error("%s", pcap_geterr(pd));
1389 	if (dflag) {
1390 		bpf_dump(&fcode, dflag);
1391 		pcap_close(pd);
1392 		free(cmdbuf);
1393 		exit(0);
1394 	}
1395 	init_addrtoname(localnet, netmask);
1396         init_checksum();
1397 
1398 #ifndef WIN32
1399 	(void)setsignal(SIGPIPE, cleanup);
1400 	(void)setsignal(SIGTERM, cleanup);
1401 	(void)setsignal(SIGINT, cleanup);
1402 #endif /* WIN32 */
1403 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
1404 	(void)setsignal(SIGCHLD, child_cleanup);
1405 #endif
1406 	/* Cooperate with nohup(1) */
1407 #ifndef WIN32
1408 	if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
1409 		(void)setsignal(SIGHUP, oldhandler);
1410 #endif /* WIN32 */
1411 
1412 #ifndef WIN32
1413 	/*
1414 	 * If a user name was specified with "-Z", attempt to switch to
1415 	 * that user's UID.  This would probably be used with sudo,
1416 	 * to allow tcpdump to be run in a special restricted
1417 	 * account (if you just want to allow users to open capture
1418 	 * devices, and can't just give users that permission,
1419 	 * you'd make tcpdump set-UID or set-GID).
1420 	 *
1421 	 * Tcpdump doesn't necessarily write only to one savefile;
1422 	 * the general only way to allow a -Z instance to write to
1423 	 * savefiles as the user under whose UID it's run, rather
1424 	 * than as the user specified with -Z, would thus be to switch
1425 	 * to the original user ID before opening a capture file and
1426 	 * then switch back to the -Z user ID after opening the savefile.
1427 	 * Switching to the -Z user ID only after opening the first
1428 	 * savefile doesn't handle the general case.
1429 	 */
1430 
1431 #ifdef HAVE_CAP_NG_H
1432 	/* We are running as root and we will be writing to savefile */
1433 	if ((getuid() == 0 || geteuid() == 0) && WFileName) {
1434 		if (username) {
1435 			/* Drop all capabilities from effective set */
1436 			capng_clear(CAPNG_EFFECTIVE);
1437 			/* Add capabilities we will need*/
1438 			capng_update(CAPNG_ADD, CAPNG_PERMITTED, CAP_SETUID);
1439 			capng_update(CAPNG_ADD, CAPNG_PERMITTED, CAP_SETGID);
1440 			capng_update(CAPNG_ADD, CAPNG_PERMITTED, CAP_DAC_OVERRIDE);
1441 
1442 			capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_SETUID);
1443 			capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_SETGID);
1444 			capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
1445 
1446 			capng_apply(CAPNG_SELECT_BOTH);
1447 		}
1448 	}
1449 #endif /* HAVE_CAP_NG_H */
1450 
1451 	if (getuid() == 0 || geteuid() == 0) {
1452 		if (username || chroot_dir)
1453 			droproot(username, chroot_dir);
1454 
1455 	}
1456 #endif /* WIN32 */
1457 
1458 	if (pcap_setfilter(pd, &fcode) < 0)
1459 		error("%s", pcap_geterr(pd));
1460 #ifdef __FreeBSD__
1461 	if (RFileName == NULL && VFileName == NULL) {
1462 		static const unsigned long cmds[] = { BIOCGSTATS };
1463 
1464 		if (cap_rights_limit(pcap_fileno(pd),
1465 		    CAP_IOCTL | CAP_READ) < 0 && errno != ENOSYS) {
1466 			error("unable to limit pcap descriptor");
1467 		}
1468 		if (cap_ioctls_limit(pcap_fileno(pd), cmds,
1469 		    sizeof(cmds) / sizeof(cmds[0])) < 0 && errno != ENOSYS) {
1470 			error("unable to limit ioctls on pcap descriptor");
1471 		}
1472 	}
1473 #endif
1474 	if (WFileName) {
1475 		pcap_dumper_t *p;
1476 		/* Do not exceed the default PATH_MAX for files. */
1477 		dumpinfo.CurrentFileName = (char *)malloc(PATH_MAX + 1);
1478 
1479 		if (dumpinfo.CurrentFileName == NULL)
1480 			error("malloc of dumpinfo.CurrentFileName");
1481 
1482 		/* We do not need numbering for dumpfiles if Cflag isn't set. */
1483 		if (Cflag != 0)
1484 		  MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, WflagChars);
1485 		else
1486 		  MakeFilename(dumpinfo.CurrentFileName, WFileName, 0, 0);
1487 
1488 		p = pcap_dump_open(pd, dumpinfo.CurrentFileName);
1489 #ifdef HAVE_CAP_NG_H
1490         /* Give up capabilities, clear Effective set */
1491         capng_clear(CAPNG_EFFECTIVE);
1492 #endif
1493 		if (p == NULL)
1494 			error("%s", pcap_geterr(pd));
1495 #ifdef __FreeBSD__
1496 		if (cap_rights_limit(fileno(pcap_dump_file(p)),
1497 		    CAP_SEEK | CAP_WRITE) < 0 && errno != ENOSYS) {
1498 			error("unable to limit dump descriptor");
1499 		}
1500 #endif
1501 		if (Cflag != 0 || Gflag != 0) {
1502 #ifdef __FreeBSD__
1503 			dumpinfo.WFileName = strdup(basename(WFileName));
1504 			dumpinfo.dirfd = open(dirname(WFileName),
1505 			    O_DIRECTORY | O_RDONLY);
1506 			if (dumpinfo.dirfd < 0) {
1507 				error("unable to open directory %s",
1508 				    dirname(WFileName));
1509 			}
1510 			if (cap_rights_limit(dumpinfo.dirfd, CAP_CREATE |
1511 			    CAP_FCNTL | CAP_FTRUNCATE | CAP_LOOKUP | CAP_SEEK |
1512 			    CAP_WRITE) < 0 && errno != ENOSYS) {
1513 				error("unable to limit directory rights");
1514 			}
1515 #else	/* !__FreeBSD__ */
1516 			dumpinfo.WFileName = WFileName;
1517 #endif
1518 			callback = dump_packet_and_trunc;
1519 			dumpinfo.pd = pd;
1520 			dumpinfo.p = p;
1521 			pcap_userdata = (u_char *)&dumpinfo;
1522 		} else {
1523 			callback = dump_packet;
1524 			pcap_userdata = (u_char *)p;
1525 		}
1526 #ifdef HAVE_PCAP_DUMP_FLUSH
1527 		if (Uflag)
1528 			pcap_dump_flush(p);
1529 #endif
1530 	} else {
1531 		type = pcap_datalink(pd);
1532 		printinfo = get_print_info(type);
1533 		callback = print_packet;
1534 		pcap_userdata = (u_char *)&printinfo;
1535 	}
1536 
1537 #ifdef SIGNAL_REQ_INFO
1538 	/*
1539 	 * We can't get statistics when reading from a file rather
1540 	 * than capturing from a device.
1541 	 */
1542 	if (RFileName == NULL)
1543 		(void)setsignal(SIGNAL_REQ_INFO, requestinfo);
1544 #endif
1545 
1546 	if (vflag > 0 && WFileName) {
1547 		/*
1548 		 * When capturing to a file, "-v" means tcpdump should,
1549 		 * every 10 secodns, "v"erbosely report the number of
1550 		 * packets captured.
1551 		 */
1552 #ifdef USE_WIN32_MM_TIMER
1553 		/* call verbose_stats_dump() each 1000 +/-100msec */
1554 		timer_id = timeSetEvent(1000, 100, verbose_stats_dump, 0, TIME_PERIODIC);
1555 		setvbuf(stderr, NULL, _IONBF, 0);
1556 #elif defined(HAVE_ALARM)
1557 		(void)setsignal(SIGALRM, verbose_stats_dump);
1558 		alarm(1);
1559 #endif
1560 	}
1561 
1562 #ifndef WIN32
1563 	if (RFileName == NULL) {
1564 		/*
1565 		 * Live capture (if -V was specified, we set RFileName
1566 		 * to a file from the -V file).  Print a message to
1567 		 * the standard error on UN*X.
1568 		 */
1569 		if (!vflag && !WFileName) {
1570 			(void)fprintf(stderr,
1571 			    "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
1572 			    program_name);
1573 		} else
1574 			(void)fprintf(stderr, "%s: ", program_name);
1575 		dlt = pcap_datalink(pd);
1576 		dlt_name = pcap_datalink_val_to_name(dlt);
1577 		if (dlt_name == NULL) {
1578 			(void)fprintf(stderr, "listening on %s, link-type %u, capture size %u bytes\n",
1579 			    device, dlt, snaplen);
1580 		} else {
1581 			(void)fprintf(stderr, "listening on %s, link-type %s (%s), capture size %u bytes\n",
1582 			    device, dlt_name,
1583 			    pcap_datalink_val_to_description(dlt), snaplen);
1584 		}
1585 		(void)fflush(stderr);
1586 	}
1587 #endif /* WIN32 */
1588 
1589 #ifdef __FreeBSD__
1590 	cansandbox = (nflag && VFileName == NULL && zflag == NULL);
1591 	if (cansandbox && cap_enter() < 0 && errno != ENOSYS)
1592 		error("unable to enter the capability mode");
1593 	if (cap_sandboxed())
1594 		fprintf(stderr, "capability mode sandbox enabled\n");
1595 #endif
1596 
1597 	do {
1598 		status = pcap_loop(pd, cnt, callback, pcap_userdata);
1599 		if (WFileName == NULL) {
1600 			/*
1601 			 * We're printing packets.  Flush the printed output,
1602 			 * so it doesn't get intermingled with error output.
1603 			 */
1604 			if (status == -2) {
1605 				/*
1606 				 * We got interrupted, so perhaps we didn't
1607 				 * manage to finish a line we were printing.
1608 				 * Print an extra newline, just in case.
1609 				 */
1610 				putchar('\n');
1611 			}
1612 			(void)fflush(stdout);
1613 		}
1614 		if (status == -1) {
1615 			/*
1616 			 * Error.  Report it.
1617 			 */
1618 			(void)fprintf(stderr, "%s: pcap_loop: %s\n",
1619 			    program_name, pcap_geterr(pd));
1620 		}
1621 		if (RFileName == NULL) {
1622 			/*
1623 			 * We're doing a live capture.  Report the capture
1624 			 * statistics.
1625 			 */
1626 			info(1);
1627 		}
1628 		pcap_close(pd);
1629 		if (VFileName != NULL) {
1630 			ret = get_next_file(VFile, VFileLine);
1631 			if (ret) {
1632 				RFileName = VFileLine;
1633 				pd = pcap_open_offline(RFileName, ebuf);
1634 				if (pd == NULL)
1635 					error("%s", ebuf);
1636 #ifdef __FreeBSD__
1637 				if (cap_rights_limit(fileno(pcap_file(pd)),
1638 				    CAP_READ) < 0 && errno != ENOSYS) {
1639 					error("unable to limit pcap descriptor");
1640 				}
1641 #endif
1642 				new_dlt = pcap_datalink(pd);
1643 				if (WFileName && new_dlt != dlt)
1644 					error("%s: new dlt does not match original", RFileName);
1645 				printinfo = get_print_info(new_dlt);
1646 				dlt_name = pcap_datalink_val_to_name(new_dlt);
1647 				if (dlt_name == NULL) {
1648 					fprintf(stderr, "reading from file %s, link-type %u\n",
1649 					RFileName, new_dlt);
1650 				} else {
1651 					fprintf(stderr,
1652 					"reading from file %s, link-type %s (%s)\n",
1653 					RFileName, dlt_name,
1654 					pcap_datalink_val_to_description(new_dlt));
1655 				}
1656 				if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
1657 					error("%s", pcap_geterr(pd));
1658 				if (pcap_setfilter(pd, &fcode) < 0)
1659 					error("%s", pcap_geterr(pd));
1660 			}
1661 		}
1662 	}
1663 	while (ret != NULL);
1664 
1665 	free(cmdbuf);
1666 	exit(status == -1 ? 1 : 0);
1667 }
1668 
1669 /* make a clean exit on interrupts */
1670 static RETSIGTYPE
1671 cleanup(int signo _U_)
1672 {
1673 #ifdef USE_WIN32_MM_TIMER
1674 	if (timer_id)
1675 		timeKillEvent(timer_id);
1676 	timer_id = 0;
1677 #elif defined(HAVE_ALARM)
1678 	alarm(0);
1679 #endif
1680 
1681 #ifdef HAVE_PCAP_BREAKLOOP
1682 	/*
1683 	 * We have "pcap_breakloop()"; use it, so that we do as little
1684 	 * as possible in the signal handler (it's probably not safe
1685 	 * to do anything with standard I/O streams in a signal handler -
1686 	 * the ANSI C standard doesn't say it is).
1687 	 */
1688 	pcap_breakloop(pd);
1689 #else
1690 	/*
1691 	 * We don't have "pcap_breakloop()"; this isn't safe, but
1692 	 * it's the best we can do.  Print the summary if we're
1693 	 * not reading from a savefile - i.e., if we're doing a
1694 	 * live capture - and exit.
1695 	 */
1696 	if (pd != NULL && pcap_file(pd) == NULL) {
1697 		/*
1698 		 * We got interrupted, so perhaps we didn't
1699 		 * manage to finish a line we were printing.
1700 		 * Print an extra newline, just in case.
1701 		 */
1702 		putchar('\n');
1703 		(void)fflush(stdout);
1704 		info(1);
1705 	}
1706 	exit(0);
1707 #endif
1708 }
1709 
1710 /*
1711   On windows, we do not use a fork, so we do not care less about
1712   waiting a child processes to die
1713  */
1714 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
1715 static RETSIGTYPE
1716 child_cleanup(int signo _U_)
1717 {
1718   wait(NULL);
1719 }
1720 #endif /* HAVE_FORK && HAVE_VFORK */
1721 
1722 static void
1723 info(register int verbose)
1724 {
1725 	struct pcap_stat stat;
1726 
1727 	/*
1728 	 * Older versions of libpcap didn't set ps_ifdrop on some
1729 	 * platforms; initialize it to 0 to handle that.
1730 	 */
1731 	stat.ps_ifdrop = 0;
1732 	if (pcap_stats(pd, &stat) < 0) {
1733 		(void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
1734 		infoprint = 0;
1735 		return;
1736 	}
1737 
1738 	if (!verbose)
1739 		fprintf(stderr, "%s: ", program_name);
1740 
1741 	(void)fprintf(stderr, "%u packet%s captured", packets_captured,
1742 	    PLURAL_SUFFIX(packets_captured));
1743 	if (!verbose)
1744 		fputs(", ", stderr);
1745 	else
1746 		putc('\n', stderr);
1747 	(void)fprintf(stderr, "%u packet%s received by filter", stat.ps_recv,
1748 	    PLURAL_SUFFIX(stat.ps_recv));
1749 	if (!verbose)
1750 		fputs(", ", stderr);
1751 	else
1752 		putc('\n', stderr);
1753 	(void)fprintf(stderr, "%u packet%s dropped by kernel", stat.ps_drop,
1754 	    PLURAL_SUFFIX(stat.ps_drop));
1755 	if (stat.ps_ifdrop != 0) {
1756 		if (!verbose)
1757 			fputs(", ", stderr);
1758 		else
1759 			putc('\n', stderr);
1760 		(void)fprintf(stderr, "%u packet%s dropped by interface\n",
1761 		    stat.ps_ifdrop, PLURAL_SUFFIX(stat.ps_ifdrop));
1762 	} else
1763 		putc('\n', stderr);
1764 	infoprint = 0;
1765 }
1766 
1767 #if defined(HAVE_FORK) || defined(HAVE_VFORK)
1768 static void
1769 compress_savefile(const char *filename)
1770 {
1771 # ifdef HAVE_FORK
1772 	if (fork())
1773 # else
1774 	if (vfork())
1775 # endif
1776 		return;
1777 	/*
1778 	 * Set to lowest priority so that this doesn't disturb the capture
1779 	 */
1780 #ifdef NZERO
1781 	setpriority(PRIO_PROCESS, 0, NZERO - 1);
1782 #else
1783 	setpriority(PRIO_PROCESS, 0, 19);
1784 #endif
1785 	if (execlp(zflag, zflag, filename, (char *)NULL) == -1)
1786 		fprintf(stderr,
1787 			"compress_savefile:execlp(%s, %s): %s\n",
1788 			zflag,
1789 			filename,
1790 			strerror(errno));
1791 # ifdef HAVE_FORK
1792 	exit(1);
1793 # else
1794 	_exit(1);
1795 # endif
1796 }
1797 #else  /* HAVE_FORK && HAVE_VFORK */
1798 static void
1799 compress_savefile(const char *filename)
1800 {
1801 	fprintf(stderr,
1802 		"compress_savefile failed. Functionality not implemented under your system\n");
1803 }
1804 #endif /* HAVE_FORK && HAVE_VFORK */
1805 
1806 static void
1807 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1808 {
1809 	struct dump_info *dump_info;
1810 
1811 	++packets_captured;
1812 
1813 	++infodelay;
1814 
1815 	dump_info = (struct dump_info *)user;
1816 
1817 	/*
1818 	 * XXX - this won't force the file to rotate on the specified time
1819 	 * boundary, but it will rotate on the first packet received after the
1820 	 * specified Gflag number of seconds. Note: if a Gflag time boundary
1821 	 * and a Cflag size boundary coincide, the time rotation will occur
1822 	 * first thereby cancelling the Cflag boundary (since the file should
1823 	 * be 0).
1824 	 */
1825 	if (Gflag != 0) {
1826 		/* Check if it is time to rotate */
1827 		time_t t;
1828 
1829 		/* Get the current time */
1830 		if ((t = time(NULL)) == (time_t)-1) {
1831 			error("dump_and_trunc_packet: can't get current_time: %s",
1832 			    pcap_strerror(errno));
1833 		}
1834 
1835 
1836 		/* If the time is greater than the specified window, rotate */
1837 		if (t - Gflag_time >= Gflag) {
1838 #ifdef __FreeBSD__
1839 			FILE *fp;
1840 			int fd;
1841 #endif
1842 
1843 			/* Update the Gflag_time */
1844 			Gflag_time = t;
1845 			/* Update Gflag_count */
1846 			Gflag_count++;
1847 			/*
1848 			 * Close the current file and open a new one.
1849 			 */
1850 			pcap_dump_close(dump_info->p);
1851 
1852 			/*
1853 			 * Compress the file we just closed, if the user asked for it
1854 			 */
1855 			if (zflag != NULL)
1856 				compress_savefile(dump_info->CurrentFileName);
1857 
1858 			/*
1859 			 * Check to see if we've exceeded the Wflag (when
1860 			 * not using Cflag).
1861 			 */
1862 			if (Cflag == 0 && Wflag > 0 && Gflag_count >= Wflag) {
1863 				(void)fprintf(stderr, "Maximum file limit reached: %d\n",
1864 				    Wflag);
1865 				exit(0);
1866 				/* NOTREACHED */
1867 			}
1868 			if (dump_info->CurrentFileName != NULL)
1869 				free(dump_info->CurrentFileName);
1870 			/* Allocate space for max filename + \0. */
1871 			dump_info->CurrentFileName = (char *)malloc(PATH_MAX + 1);
1872 			if (dump_info->CurrentFileName == NULL)
1873 				error("dump_packet_and_trunc: malloc");
1874 			/*
1875 			 * This is always the first file in the Cflag
1876 			 * rotation: e.g. 0
1877 			 * We also don't need numbering if Cflag is not set.
1878 			 */
1879 			if (Cflag != 0)
1880 				MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, 0,
1881 				    WflagChars);
1882 			else
1883 				MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, 0, 0);
1884 
1885 #ifdef HAVE_CAP_NG_H
1886 			capng_update(CAPNG_ADD, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
1887 			capng_apply(CAPNG_EFFECTIVE);
1888 #endif /* HAVE_CAP_NG_H */
1889 #ifdef __FreeBSD__
1890 			fd = openat(dump_info->dirfd,
1891 			    dump_info->CurrentFileName,
1892 			    O_CREAT | O_WRONLY | O_TRUNC, 0644);
1893 			if (fd < 0) {
1894 				error("unable to open file %s",
1895 				    dump_info->CurrentFileName);
1896 			}
1897 			fp = fdopen(fd, "w");
1898 			if (fp == NULL) {
1899 				error("unable to fdopen file %s",
1900 				    dump_info->CurrentFileName);
1901 			}
1902 			dump_info->p = pcap_dump_fopen(dump_info->pd, fp);
1903 #else	/* !__FreeBSD__ */
1904 			dump_info->p = pcap_dump_open(dump_info->pd, dump_info->CurrentFileName);
1905 #endif
1906 #ifdef HAVE_CAP_NG_H
1907 			capng_update(CAPNG_DROP, CAPNG_EFFECTIVE, CAP_DAC_OVERRIDE);
1908 			capng_apply(CAPNG_EFFECTIVE);
1909 #endif /* HAVE_CAP_NG_H */
1910 			if (dump_info->p == NULL)
1911 				error("%s", pcap_geterr(pd));
1912 #ifdef __FreeBSD__
1913 			if (cap_rights_limit(fileno(pcap_dump_file(dump_info->p)),
1914 			    CAP_SEEK | CAP_WRITE) < 0 && errno != ENOSYS) {
1915 				error("unable to limit dump descriptor");
1916 			}
1917 #endif
1918 		}
1919 	}
1920 
1921 	/*
1922 	 * XXX - this won't prevent capture files from getting
1923 	 * larger than Cflag - the last packet written to the
1924 	 * file could put it over Cflag.
1925 	 */
1926 	if (Cflag != 0 && pcap_dump_ftell(dump_info->p) > Cflag) {
1927 #ifdef __FreeBSD__
1928 		FILE *fp;
1929 		int fd;
1930 #endif
1931 
1932 		/*
1933 		 * Close the current file and open a new one.
1934 		 */
1935 		pcap_dump_close(dump_info->p);
1936 
1937 		/*
1938 		 * Compress the file we just closed, if the user asked for it
1939 		 */
1940 		if (zflag != NULL)
1941 			compress_savefile(dump_info->CurrentFileName);
1942 
1943 		Cflag_count++;
1944 		if (Wflag > 0) {
1945 			if (Cflag_count >= Wflag)
1946 				Cflag_count = 0;
1947 		}
1948 		if (dump_info->CurrentFileName != NULL)
1949 			free(dump_info->CurrentFileName);
1950 		dump_info->CurrentFileName = (char *)malloc(PATH_MAX + 1);
1951 		if (dump_info->CurrentFileName == NULL)
1952 			error("dump_packet_and_trunc: malloc");
1953 		MakeFilename(dump_info->CurrentFileName, dump_info->WFileName, Cflag_count, WflagChars);
1954 #ifdef __FreeBSD__
1955 		fd = openat(dump_info->dirfd, dump_info->CurrentFileName,
1956 		    O_CREAT | O_WRONLY | O_TRUNC, 0644);
1957 		if (fd < 0) {
1958 			error("unable to open file %s",
1959 			    dump_info->CurrentFileName);
1960 		}
1961 		fp = fdopen(fd, "w");
1962 		if (fp == NULL) {
1963 			error("unable to fdopen file %s",
1964 			    dump_info->CurrentFileName);
1965 		}
1966 		dump_info->p = pcap_dump_fopen(dump_info->pd, fp);
1967 #else	/* !__FreeBSD__ */
1968 		dump_info->p = pcap_dump_open(dump_info->pd, dump_info->CurrentFileName);
1969 #endif
1970 		if (dump_info->p == NULL)
1971 			error("%s", pcap_geterr(pd));
1972 #ifdef __FreeBSD__
1973 		if (cap_rights_limit(fileno(pcap_dump_file(dump_info->p)),
1974 		    CAP_SEEK | CAP_WRITE) < 0 && errno != ENOSYS) {
1975 			error("unable to limit dump descriptor");
1976 		}
1977 #endif
1978 	}
1979 
1980 	pcap_dump((u_char *)dump_info->p, h, sp);
1981 #ifdef HAVE_PCAP_DUMP_FLUSH
1982 	if (Uflag)
1983 		pcap_dump_flush(dump_info->p);
1984 #endif
1985 
1986 	--infodelay;
1987 	if (infoprint)
1988 		info(0);
1989 }
1990 
1991 static void
1992 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1993 {
1994 	++packets_captured;
1995 
1996 	++infodelay;
1997 
1998 	pcap_dump(user, h, sp);
1999 #ifdef HAVE_PCAP_DUMP_FLUSH
2000 	if (Uflag)
2001 		pcap_dump_flush((pcap_dumper_t *)user);
2002 #endif
2003 
2004 	--infodelay;
2005 	if (infoprint)
2006 		info(0);
2007 }
2008 
2009 static void
2010 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
2011 {
2012 	struct print_info *print_info;
2013 	u_int hdrlen;
2014 
2015 	++packets_captured;
2016 
2017 	++infodelay;
2018 	ts_print(&h->ts);
2019 
2020 	print_info = (struct print_info *)user;
2021 
2022 	/*
2023 	 * Some printers want to check that they're not walking off the
2024 	 * end of the packet.
2025 	 * Rather than pass it all the way down, we set this global.
2026 	 */
2027 	snapend = sp + h->caplen;
2028 
2029         if(print_info->ndo_type) {
2030                 hdrlen = (*print_info->p.ndo_printer)(print_info->ndo, h, sp);
2031         } else {
2032                 hdrlen = (*print_info->p.printer)(h, sp);
2033         }
2034 
2035 	if (Xflag) {
2036 		/*
2037 		 * Print the raw packet data in hex and ASCII.
2038 		 */
2039 		if (Xflag > 1) {
2040 			/*
2041 			 * Include the link-layer header.
2042 			 */
2043 			hex_and_ascii_print("\n\t", sp, h->caplen);
2044 		} else {
2045 			/*
2046 			 * Don't include the link-layer header - and if
2047 			 * we have nothing past the link-layer header,
2048 			 * print nothing.
2049 			 */
2050 			if (h->caplen > hdrlen)
2051 				hex_and_ascii_print("\n\t", sp + hdrlen,
2052 				    h->caplen - hdrlen);
2053 		}
2054 	} else if (xflag) {
2055 		/*
2056 		 * Print the raw packet data in hex.
2057 		 */
2058 		if (xflag > 1) {
2059 			/*
2060 			 * Include the link-layer header.
2061 			 */
2062 			hex_print("\n\t", sp, h->caplen);
2063 		} else {
2064 			/*
2065 			 * Don't include the link-layer header - and if
2066 			 * we have nothing past the link-layer header,
2067 			 * print nothing.
2068 			 */
2069 			if (h->caplen > hdrlen)
2070 				hex_print("\n\t", sp + hdrlen,
2071 				    h->caplen - hdrlen);
2072 		}
2073 	} else if (Aflag) {
2074 		/*
2075 		 * Print the raw packet data in ASCII.
2076 		 */
2077 		if (Aflag > 1) {
2078 			/*
2079 			 * Include the link-layer header.
2080 			 */
2081 			ascii_print(sp, h->caplen);
2082 		} else {
2083 			/*
2084 			 * Don't include the link-layer header - and if
2085 			 * we have nothing past the link-layer header,
2086 			 * print nothing.
2087 			 */
2088 			if (h->caplen > hdrlen)
2089 				ascii_print(sp + hdrlen, h->caplen - hdrlen);
2090 		}
2091 	}
2092 
2093 	putchar('\n');
2094 
2095 	--infodelay;
2096 	if (infoprint)
2097 		info(0);
2098 }
2099 
2100 #ifdef WIN32
2101 	/*
2102 	 * XXX - there should really be libpcap calls to get the version
2103 	 * number as a string (the string would be generated from #defines
2104 	 * at run time, so that it's not generated from string constants
2105 	 * in the library, as, on many UNIX systems, those constants would
2106 	 * be statically linked into the application executable image, and
2107 	 * would thus reflect the version of libpcap on the system on
2108 	 * which the application was *linked*, not the system on which it's
2109 	 * *running*.
2110 	 *
2111 	 * That routine should be documented, unlike the "version[]"
2112 	 * string, so that UNIX vendors providing their own libpcaps
2113 	 * don't omit it (as a couple of vendors have...).
2114 	 *
2115 	 * Packet.dll should perhaps also export a routine to return the
2116 	 * version number of the Packet.dll code, to supply the
2117 	 * "Wpcap_version" information on Windows.
2118 	 */
2119 	char WDversion[]="current-cvs.tcpdump.org";
2120 #if !defined(HAVE_GENERATED_VERSION)
2121 	char version[]="current-cvs.tcpdump.org";
2122 #endif
2123 	char pcap_version[]="current-cvs.tcpdump.org";
2124 	char Wpcap_version[]="3.1";
2125 #endif
2126 
2127 /*
2128  * By default, print the specified data out in hex and ASCII.
2129  */
2130 static void
2131 ndo_default_print(netdissect_options *ndo _U_, const u_char *bp, u_int length)
2132 {
2133 	hex_and_ascii_print("\n\t", bp, length); /* pass on lf and identation string */
2134 }
2135 
2136 void
2137 default_print(const u_char *bp, u_int length)
2138 {
2139 	ndo_default_print(gndo, bp, length);
2140 }
2141 
2142 #ifdef SIGNAL_REQ_INFO
2143 RETSIGTYPE requestinfo(int signo _U_)
2144 {
2145 	if (infodelay)
2146 		++infoprint;
2147 	else
2148 		info(0);
2149 }
2150 #endif
2151 
2152 /*
2153  * Called once each second in verbose mode while dumping to file
2154  */
2155 #ifdef USE_WIN32_MM_TIMER
2156 void CALLBACK verbose_stats_dump (UINT timer_id _U_, UINT msg _U_, DWORD_PTR arg _U_,
2157 				  DWORD_PTR dw1 _U_, DWORD_PTR dw2 _U_)
2158 {
2159 	struct pcap_stat stat;
2160 
2161 	if (infodelay == 0 && pcap_stats(pd, &stat) >= 0)
2162 		fprintf(stderr, "Got %u\r", packets_captured);
2163 }
2164 #elif defined(HAVE_ALARM)
2165 static void verbose_stats_dump(int sig _U_)
2166 {
2167 	struct pcap_stat stat;
2168 
2169 	if (infodelay == 0 && pcap_stats(pd, &stat) >= 0)
2170 		fprintf(stderr, "Got %u\r", packets_captured);
2171 	alarm(1);
2172 }
2173 #endif
2174 
2175 static void
2176 usage(void)
2177 {
2178 	extern char version[];
2179 #ifndef HAVE_PCAP_LIB_VERSION
2180 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
2181 	extern char pcap_version[];
2182 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
2183 	static char pcap_version[] = "unknown";
2184 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
2185 #endif /* HAVE_PCAP_LIB_VERSION */
2186 
2187 #ifdef HAVE_PCAP_LIB_VERSION
2188 #ifdef WIN32
2189 	(void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
2190 #else /* WIN32 */
2191 	(void)fprintf(stderr, "%s version %s\n", program_name, version);
2192 #endif /* WIN32 */
2193 	(void)fprintf(stderr, "%s\n",pcap_lib_version());
2194 #else /* HAVE_PCAP_LIB_VERSION */
2195 #ifdef WIN32
2196 	(void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
2197 	(void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
2198 #else /* WIN32 */
2199 	(void)fprintf(stderr, "%s version %s\n", program_name, version);
2200 	(void)fprintf(stderr, "libpcap version %s\n", pcap_version);
2201 #endif /* WIN32 */
2202 #endif /* HAVE_PCAP_LIB_VERSION */
2203 	(void)fprintf(stderr,
2204 "Usage: %s [-aAbd" D_FLAG "efhH" I_FLAG J_FLAG "KlLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [ -c count ]\n", program_name);
2205 	(void)fprintf(stderr,
2206 "\t\t[ -C file_size ] [ -E algo:secret ] [ -F file ] [ -G seconds ]\n");
2207 	(void)fprintf(stderr,
2208 "\t\t[ -i interface ]" j_FLAG_USAGE " [ -M secret ]\n");
2209 	(void)fprintf(stderr,
2210 "\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ -V file ] [ -w file ]\n");
2211 	(void)fprintf(stderr,
2212 "\t\t[ -W filecount ] [ -y datalinktype ] [ -z command ]\n");
2213 	(void)fprintf(stderr,
2214 "\t\t[ -Z user ] [ expression ]\n");
2215 	exit(1);
2216 }
2217 
2218 
2219 
2220 /* VARARGS */
2221 static void
2222 ndo_error(netdissect_options *ndo _U_, const char *fmt, ...)
2223 {
2224 	va_list ap;
2225 
2226 	(void)fprintf(stderr, "%s: ", program_name);
2227 	va_start(ap, fmt);
2228 	(void)vfprintf(stderr, fmt, ap);
2229 	va_end(ap);
2230 	if (*fmt) {
2231 		fmt += strlen(fmt);
2232 		if (fmt[-1] != '\n')
2233 			(void)fputc('\n', stderr);
2234 	}
2235 	exit(1);
2236 	/* NOTREACHED */
2237 }
2238 
2239 /* VARARGS */
2240 static void
2241 ndo_warning(netdissect_options *ndo _U_, const char *fmt, ...)
2242 {
2243 	va_list ap;
2244 
2245 	(void)fprintf(stderr, "%s: WARNING: ", program_name);
2246 	va_start(ap, fmt);
2247 	(void)vfprintf(stderr, fmt, ap);
2248 	va_end(ap);
2249 	if (*fmt) {
2250 		fmt += strlen(fmt);
2251 		if (fmt[-1] != '\n')
2252 			(void)fputc('\n', stderr);
2253 	}
2254 }
2255