The Tcpdump Group git mirrors - tcpdump/blob - tcpdump.c

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  *
  21  * Support for splitting captures into multiple files with a maximum
  22  * file size:
  23  *
  24  * Copyright (c) 2001
  25  *      Seth Webster <swebster@sst.ll.mit.edu>
  26  */
  27
  28 #ifndef lint
  29 static const char copyright[] _U_ =
  30     "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
  31 The Regents of the University of California.  All rights reserved.\n";
  32 static const char rcsid[] _U_ =
  33     "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.248 2004-09-04 00:08:04 guy Exp $ (LBL)";
  34 #endif
  35
  36 /*
  37  * tcpdump - monitor tcp/ip traffic on an ethernet.
  38  *
  39  * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
  40  * Mercilessly hacked and occasionally improved since then via the
  41  * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
  42  */
  43
  44 #ifdef HAVE_CONFIG_H
  45 #include "config.h"
  46 #endif
  47
  48 #include <tcpdump-stdinc.h>
  49
  50 #ifdef WIN32
  51 #include "getopt.h"
  52 #include "w32_fzs.h"
  53 extern int strcasecmp (const char *__s1, const char *__s2);
  54 extern int SIZE_BUF;
  55 #define off_t long
  56 #define uint UINT
  57 #endif /* WIN32 */
  58
  59 #ifdef HAVE_SMI_H
  60 #include <smi.h>
  61 #endif
  62
  63 #include <pcap.h>
  64 #include <signal.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68 #ifndef WIN32
  69 #include <pwd.h>
  70 #include <grp.h>
  71 #include <errno.h>
  72 #endif /* WIN32 */
  73
  74 #include "netdissect.h"
  75 #include "interface.h"
  76 #include "addrtoname.h"
  77 #include "machdep.h"
  78 #include "setsignal.h"
  79 #include "gmt2local.h"
  80 #include "pcap-missing.h"
  81
  82 netdissect_options Gndo;
  83 netdissect_options *gndo = &Gndo;
  84
  85 /*
  86  * Define the maximum number of files for the -C flag, and how many
  87  * characters can be added to a filename for the -C flag (which
  88  * should be enough to handle MAX_CFLAG - 1).
  89  */
  90 #define MAX_CFLAG       1000000
  91 #define MAX_CFLAG_CHARS 6
  92
  93 int Lflag;          /* list available data link types and exit */
  94
  95 static int infodelay;
  96 static int infoprint;
  97
  98 char *program_name;
  99
 100 int32_t thiszone;               /* seconds offset from gmt to local time */
 101
 102 /* Forwards */
 103 static RETSIGTYPE cleanup(int);
 104 static void usage(void) __attribute__((noreturn));
 105 static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
 106
 107 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 108 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 109 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 110 static void droproot(const char *, const char *);
 111 static void ndo_error(netdissect_options *ndo, const char *fmt, ...);
 112 static void ndo_warning(netdissect_options *ndo, const char *fmt, ...);
 113
 114 #ifdef SIGINFO
 115 RETSIGTYPE requestinfo(int);
 116 #endif
 117
 118 #if defined(USE_WIN32_MM_TIMER)
 119   #include <MMsystem.h>
 120   static UINT timer_id;
 121   static void CALLBACK verbose_stats_dump(UINT, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR);
 122 #elif defined(HAVE_ALARM)
 123   static void verbose_stats_dump(int sig);
 124 #endif
 125
 126 static void info(int);
 127 static u_int packets_captured;
 128
 129 typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);
 130
 131 struct printer {
 132         if_printer f;
 133         int type;
 134 };
 135
 136 static struct printer printers[] = {
 137         { arcnet_if_print,      DLT_ARCNET },
 138 #ifdef DLT_ARCNET_LINUX
 139         { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 140 #endif
 141         { ether_if_print,       DLT_EN10MB },
 142         { token_if_print,       DLT_IEEE802 },
 143 #ifdef DLT_LANE8023
 144         { lane_if_print,        DLT_LANE8023 },
 145 #endif
 146 #ifdef DLT_CIP
 147         { cip_if_print,         DLT_CIP },
 148 #endif
 149 #ifdef DLT_ATM_CLIP
 150         { cip_if_print,         DLT_ATM_CLIP },
 151 #endif
 152         { sl_if_print,          DLT_SLIP },
 153 #ifdef DLT_SLIP_BSDOS
 154         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 155 #endif
 156         { ppp_if_print,         DLT_PPP },
 157 #ifdef DLT_PPP_WITHDIRECTION
 158         { ppp_if_print,         DLT_PPP_WITHDIRECTION },
 159 #endif
 160 #ifdef DLT_PPP_BSDOS
 161         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 162 #endif
 163         { fddi_if_print,        DLT_FDDI },
 164         { null_if_print,        DLT_NULL },
 165 #ifdef DLT_LOOP
 166         { null_if_print,        DLT_LOOP },
 167 #endif
 168         { raw_if_print,         DLT_RAW },
 169         { atm_if_print,         DLT_ATM_RFC1483 },
 170 #ifdef DLT_C_HDLC
 171         { chdlc_if_print,       DLT_C_HDLC },
 172 #endif
 173 #ifdef DLT_HDLC
 174         { chdlc_if_print,       DLT_HDLC },
 175 #endif
 176 #ifdef DLT_PPP_SERIAL
 177         { ppp_hdlc_if_print,    DLT_PPP_SERIAL },
 178 #endif
 179 #ifdef DLT_PPP_ETHER
 180         { pppoe_if_print,       DLT_PPP_ETHER },
 181 #endif
 182 #ifdef DLT_LINUX_SLL
 183         { sll_if_print,         DLT_LINUX_SLL },
 184 #endif
 185 #ifdef DLT_IEEE802_11
 186         { ieee802_11_if_print,  DLT_IEEE802_11},
 187 #endif
 188 #ifdef DLT_LTALK
 189         { ltalk_if_print,       DLT_LTALK },
 190 #endif
 191 #ifdef DLT_PFLOG
 192         { pflog_if_print,       DLT_PFLOG },
 193 #endif
 194 #ifdef DLT_FR
 195         { fr_if_print,          DLT_FR },
 196 #endif
 197 #ifdef DLT_FRELAY
 198         { fr_if_print,          DLT_FRELAY },
 199 #endif
 200 #ifdef DLT_SUNATM
 201         { sunatm_if_print,      DLT_SUNATM },
 202 #endif
 203 #ifdef DLT_IP_OVER_FC
 204         { ipfc_if_print,        DLT_IP_OVER_FC },
 205 #endif
 206 #ifdef DLT_PRISM_HEADER
 207         { prism_if_print,       DLT_PRISM_HEADER },
 208 #endif
 209 #ifdef DLT_IEEE802_11_RADIO
 210         { ieee802_11_radio_if_print,    DLT_IEEE802_11_RADIO },
 211 #endif
 212 #ifdef DLT_ENC
 213         { enc_if_print,         DLT_ENC },
 214 #endif
 215 #ifdef DLT_SYMANTEC_FIREWALL
 216         { symantec_if_print,    DLT_SYMANTEC_FIREWALL },
 217 #endif
 218 #ifdef DLT_APPLE_IP_OVER_IEEE1394
 219         { ap1394_if_print,      DLT_APPLE_IP_OVER_IEEE1394 },
 220 #endif
 221         { NULL,                 0 },
 222 };
 223
 224 static if_printer
 225 lookup_printer(int type)
 226 {
 227         struct printer *p;
 228
 229         for (p = printers; p->f; ++p)
 230                 if (type == p->type)
 231                         return p->f;
 232
 233         return NULL;
 234         /* NOTREACHED */
 235 }
 236
 237 static pcap_t *pd;
 238
 239 extern int optind;
 240 extern int opterr;
 241 extern char *optarg;
 242
 243 struct print_info {
 244         if_printer printer;
 245 };
 246
 247 struct dump_info {
 248         char    *WFileName;
 249         pcap_t  *pd;
 250         pcap_dumper_t *p;
 251 };
 252
 253 static void
 254 show_dlts_and_exit(pcap_t *pd)
 255 {
 256         int n_dlts;
 257         int *dlts = 0;
 258         const char *dlt_name;
 259
 260         n_dlts = pcap_list_datalinks(pd, &dlts);
 261         if (n_dlts < 0)
 262                 error("%s", pcap_geterr(pd));
 263         else if (n_dlts == 0 || !dlts)
 264                 error("No data link types.");
 265
 266         (void) fprintf(stderr, "Data link types (use option -y to set):\n");
 267
 268         while (--n_dlts >= 0) {
 269                 dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
 270                 if (dlt_name != NULL) {
 271                         (void) fprintf(stderr, "  %s (%s)", dlt_name,
 272                             pcap_datalink_val_to_description(dlts[n_dlts]));
 273
 274                         /*
 275                          * OK, does tcpdump handle that type?
 276                          */
 277                         if (lookup_printer(dlts[n_dlts]) == NULL)
 278                                 (void) fprintf(stderr, " (not supported)");
 279                         putchar('\n');
 280                 } else {
 281                         (void) fprintf(stderr, "  DLT %d (not supported)\n",
 282                             dlts[n_dlts]);
 283                 }
 284         }
 285         free(dlts);
 286         exit(0);
 287 }
 288
 289 /*
 290  * Set up flags that might or might not be supported depending on the
 291  * version of libpcap we're using.
 292  */
 293 #ifdef WIN32
 294 #define B_FLAG          "B:"
 295 #define B_FLAG_USAGE    " [ -B size ]"
 296 #else /* WIN32 */
 297 #define B_FLAG
 298 #define B_FLAG_USAGE
 299 #endif /* WIN32 */
 300
 301 #ifdef HAVE_PCAP_FINDALLDEVS
 302 #ifndef HAVE_PCAP_IF_T
 303 #undef HAVE_PCAP_FINDALLDEVS
 304 #endif
 305 #endif
 306
 307 #ifdef HAVE_PCAP_FINDALLDEVS
 308 #define D_FLAG  "D"
 309 #else
 310 #define D_FLAG
 311 #endif
 312
 313 #ifdef HAVE_PCAP_DUMP_FLUSH
 314 #define U_FLAG  "U"
 315 #else
 316 #define U_FLAG
 317 #endif
 318
 319 #ifndef WIN32
 320 /* Drop root privileges and chroot if necessary */
 321 static void
 322 droproot(const char *username, const char *chroot_dir)
 323 {
 324         struct passwd *pw = NULL;
 325
 326         if (chroot_dir && !username) {
 327                 fprintf(stderr, "tcpdump: Chroot without dropping root is insecure\n");
 328                 exit(1);
 329         }
 330
 331         pw = getpwnam(username);
 332         if (pw) {
 333                 if (chroot_dir) {
 334                         if (chroot(chroot_dir) != 0 || chdir ("/") != 0) {
 335                                 fprintf(stderr, "tcpdump: Couldn't chroot/chdir to '%.64s': %s\n",
 336                                     chroot_dir, pcap_strerror(errno));
 337                                 exit(1);
 338                         }
 339                 }
 340                 if (initgroups(pw->pw_name, pw->pw_gid) != 0 ||
 341                     setgid(pw->pw_gid) != 0 || setuid(pw->pw_uid) != 0) {
 342                         fprintf(stderr, "tcpdump: Couldn't change to '%.32s' uid=%lu gid=%lu: %s\n",
 343                             username,
 344                             (unsigned long)pw->pw_uid,
 345                             (unsigned long)pw->pw_gid,
 346                             pcap_strerror(errno));
 347                         exit(1);
 348                 }
 349         }
 350         else {
 351                 fprintf(stderr, "tcpdump: Couldn't find user '%.32s'\n",
 352                     username);
 353                 exit(1);
 354         }
 355 }
 356 #endif /* WIN32 */
 357
 358 static int
 359 getWflagChars(int x)
 360 {
 361         int c = 0;
 362
 363         x -= 1;
 364         while (x > 0) {
 365                 c += 1;
 366                 x /= 10;
 367         }
 368
 369         return c;
 370 }
 371
 372
 373 static void
 374 MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
 375 {
 376         if (cnt == 0 && max_chars == 0)
 377                 strcpy(buffer, orig_name);
 378         else
 379                 sprintf(buffer, "%s%0*d", orig_name, max_chars, cnt);
 380 }
 381
 382 static int tcpdump_printf(netdissect_options *ndo _U_,
 383                           const char *fmt, ...)
 384 {
 385
 386   va_list args;
 387   int ret;
 388
 389   va_start(args, fmt);
 390   ret=vfprintf(stdout, fmt, args);
 391   va_end(args);
 392
 393   return ret;
 394 }
 395
 396 int
 397 main(int argc, char **argv)
 398 {
 399         register int cnt, op, i;
 400         bpf_u_int32 localnet, netmask;
 401         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName, *WFileNameAlt;
 402         pcap_handler callback;
 403         int type;
 404         struct bpf_program fcode;
 405 #ifndef WIN32
 406         RETSIGTYPE (*oldhandler)(int);
 407 #endif
 408         struct print_info printinfo;
 409         struct dump_info dumpinfo;
 410         u_char *pcap_userdata;
 411         char ebuf[PCAP_ERRBUF_SIZE];
 412         char *username = NULL;
 413         char *chroot_dir = NULL;
 414 #ifdef HAVE_PCAP_FINDALLDEVS
 415         pcap_if_t *devpointer;
 416         int devnum;
 417 #endif
 418         int status;
 419 #ifdef WIN32
 420         u_int UserBufferSize = 1000000;
 421         if(wsockinit() != 0) return 1;
 422 #endif /* WIN32 */
 423
 424         gndo->ndo_Oflag=1;
 425         gndo->ndo_Rflag=1;
 426         gndo->ndo_dlt=-1;
 427         gndo->ndo_printf=tcpdump_printf;
 428         gndo->ndo_error=ndo_error;
 429         gndo->ndo_warning=ndo_warning;
 430         gndo->ndo_snaplen = DEFAULT_SNAPLEN;
 431
 432         cnt = -1;
 433         device = NULL;
 434         infile = NULL;
 435         RFileName = NULL;
 436         WFileName = NULL;
 437         if ((cp = strrchr(argv[0], '/')) != NULL)
 438                 program_name = cp + 1;
 439         else
 440                 program_name = argv[0];
 441
 442         if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
 443                 error("%s", ebuf);
 444
 445 #ifdef LIBSMI
 446         smiInit("tcpdump");
 447 #endif
 448
 449         opterr = 0;
 450         while (
 451             (op = getopt(argc, argv, "aA" B_FLAG "c:C:d" D_FLAG "eE:fF:i:lLm:M:nNOpqr:Rs:StT:u" U_FLAG "vw:W:xXy:YZ:")) != -1)
 452                 switch (op) {
 453
 454                 case 'a':
 455                         /* compatibility for old -a */
 456                         break;
 457
 458                 case 'A':
 459                         ++xflag;
 460                         ++Xflag;
 461                         ++Aflag;
 462                         break;
 463
 464 #ifdef WIN32
 465                 case 'B':
 466                         UserBufferSize = atoi(optarg)*1024;
 467                         if (UserBufferSize < 0)
 468                                 error("invalid packet buffer size %s", optarg);
 469                         break;
 470 #endif /* WIN32 */
 471
 472                 case 'c':
 473                         cnt = atoi(optarg);
 474                         if (cnt <= 0)
 475                                 error("invalid packet count %s", optarg);
 476                         break;
 477
 478                 case 'C':
 479                         Cflag = atoi(optarg) * 1000000;
 480                         if (Cflag < 0)
 481                                 error("invalid file size %s", optarg);
 482                         break;
 483
 484                 case 'd':
 485                         ++dflag;
 486                         break;
 487
 488 #ifdef HAVE_PCAP_FINDALLDEVS
 489                 case 'D':
 490                         if (pcap_findalldevs(&devpointer, ebuf) < 0)
 491                                 error("%s", ebuf);
 492                         else {
 493                                 for (i = 0; devpointer != 0; i++) {
 494                                         printf("%d.%s", i+1, devpointer->name);
 495                                         if (devpointer->description != NULL)
 496                                                 printf(" (%s)", devpointer->description);
 497                                         printf("\n");
 498                                         devpointer = devpointer->next;
 499                                 }
 500                         }
 501                         return 0;
 502 #endif /* HAVE_PCAP_FINDALLDEVS */
 503
 504                 case 'L':
 505                         Lflag++;
 506                         break;
 507
 508                 case 'e':
 509                         ++eflag;
 510                         break;
 511
 512                 case 'E':
 513 #ifndef HAVE_LIBCRYPTO
 514                         warning("crypto code not compiled in");
 515 #endif
 516                         gndo->ndo_espsecret = optarg;
 517                         break;
 518
 519                 case 'f':
 520                         ++fflag;
 521                         break;
 522
 523                 case 'F':
 524                         infile = optarg;
 525                         break;
 526
 527                 case 'i':
 528                         if (optarg[0] == '0' && optarg[1] == 0)
 529                                 error("Invalid adapter index");
 530
 531 #ifdef HAVE_PCAP_FINDALLDEVS
 532                         /*
 533                          * If the argument is a number, treat it as
 534                          * an index into the list of adapters, as
 535                          * printed by "tcpdump -D".
 536                          *
 537                          * This should be OK on UNIX systems, as interfaces
 538                          * shouldn't have names that begin with digits.
 539                          * It can be useful on Windows, where more than
 540                          * one interface can have the same name.
 541                          */
 542                         if ((devnum = atoi(optarg)) != 0) {
 543                                 if (devnum < 0)
 544                                         error("Invalid adapter index");
 545
 546                                 if (pcap_findalldevs(&devpointer, ebuf) < 0)
 547                                         error("%s", ebuf);
 548                                 else {
 549                                         for (i = 0; i < devnum-1; i++){
 550                                                 devpointer = devpointer->next;
 551                                                 if (devpointer == NULL)
 552                                                         error("Invalid adapter index");
 553                                         }
 554                                 }
 555                                 device = devpointer->name;
 556                                 break;
 557                         }
 558 #endif /* HAVE_PCAP_FINDALLDEVS */
 559                         device = optarg;
 560                         break;
 561
 562                 case 'l':
 563 #ifdef WIN32
 564                         /*
 565                          * _IOLBF is the same as _IOFBF in Microsoft's C
 566                          * libraries; the only alternative they offer
 567                          * is _IONBF.
 568                          *
 569                          * XXX - this should really be checking for MSVC++,
 570                          * not WIN32, if, for example, MinGW has its own
 571                          * C library that is more UNIX-compatible.
 572                          */
 573                         setvbuf(stdout, NULL, _IONBF, 0);
 574 #else /* WIN32 */
 575 #ifdef HAVE_SETLINEBUF
 576                         setlinebuf(stdout);
 577 #else
 578                         setvbuf(stdout, NULL, _IOLBF, 0);
 579 #endif
 580 #endif /* WIN32 */
 581                         break;
 582
 583                 case 'n':
 584                         ++nflag;
 585                         break;
 586
 587                 case 'N':
 588                         ++Nflag;
 589                         break;
 590
 591                 case 'm':
 592 #ifdef LIBSMI
 593                         if (smiLoadModule(optarg) == 0) {
 594                                 error("could not load MIB module %s", optarg);
 595                         }
 596                         sflag = 1;
 597 #else
 598                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 599                                       program_name, optarg);
 600                         (void)fprintf(stderr, "(no libsmi support)\n");
 601 #endif
 602                         break;
 603
 604                 case 'M':
 605                         /* TCP-MD5 shared secret */
 606 #ifndef HAVE_LIBCRYPTO
 607                         warning("crypto code not compiled in");
 608 #endif
 609                         tcpmd5secret = optarg;
 610                         break;
 611
 612                 case 'O':
 613                         Oflag = 0;
 614                         break;
 615
 616                 case 'p':
 617                         ++pflag;
 618                         break;
 619
 620                 case 'q':
 621                         ++qflag;
 622                         break;
 623
 624                 case 'r':
 625                         RFileName = optarg;
 626                         break;
 627
 628                 case 'R':
 629                         Rflag = 0;
 630                         break;
 631
 632                 case 's': {
 633                         char *end;
 634
 635                         snaplen = strtol(optarg, &end, 0);
 636                         if (optarg == end || *end != '\0'
 637                             || snaplen < 0 || snaplen > 65535)
 638                                 error("invalid snaplen %s", optarg);
 639                         else if (snaplen == 0)
 640                                 snaplen = 65535;
 641                         break;
 642                 }
 643
 644                 case 'S':
 645                         ++Sflag;
 646                         break;
 647
 648                 case 't':
 649                         ++tflag;
 650                         break;
 651
 652                 case 'T':
 653                         if (strcasecmp(optarg, "vat") == 0)
 654                                 packettype = PT_VAT;
 655                         else if (strcasecmp(optarg, "wb") == 0)
 656                                 packettype = PT_WB;
 657                         else if (strcasecmp(optarg, "rpc") == 0)
 658                                 packettype = PT_RPC;
 659                         else if (strcasecmp(optarg, "rtp") == 0)
 660                                 packettype = PT_RTP;
 661                         else if (strcasecmp(optarg, "rtcp") == 0)
 662                                 packettype = PT_RTCP;
 663                         else if (strcasecmp(optarg, "snmp") == 0)
 664                                 packettype = PT_SNMP;
 665                         else if (strcasecmp(optarg, "cnfp") == 0)
 666                                 packettype = PT_CNFP;
 667                         else if (strcasecmp(optarg, "tftp") == 0)
 668                                 packettype = PT_TFTP;
 669                         else if (strcasecmp(optarg, "aodv") == 0)
 670                                 packettype = PT_AODV;
 671                         else
 672                                 error("unknown packet type `%s'", optarg);
 673                         break;
 674
 675                 case 'u':
 676                         ++uflag;
 677                         break;
 678
 679 #ifdef HAVE_PCAP_DUMP_FLUSH
 680                 case 'U':
 681                         ++Uflag;
 682                         break;
 683 #endif
 684
 685                 case 'v':
 686                         ++vflag;
 687                         break;
 688
 689                 case 'w':
 690                         WFileName = optarg;
 691                         break;
 692
 693                 case 'W':
 694                         Wflag = atoi(optarg);
 695                         if (Wflag < 0)
 696                                 error("invalid number of output files %s", optarg);
 697                         WflagChars = getWflagChars(Wflag);
 698                         break;
 699
 700                 case 'x':
 701                         ++xflag;
 702                         break;
 703
 704                 case 'X':
 705                         ++Xflag;
 706                         break;
 707
 708                 case 'y':
 709                         gndo->ndo_dltname = optarg;
 710                         gndo->ndo_dlt =
 711                           pcap_datalink_name_to_val(gndo->ndo_dltname);
 712                         if (gndo->ndo_dlt < 0)
 713                                 error("invalid data link type %s", gndo->ndo_dltname);
 714                         break;
 715
 716 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
 717                 case 'Y':
 718                         {
 719                         /* Undocumented flag */
 720 #ifdef HAVE_PCAP_DEBUG
 721                         extern int pcap_debug;
 722                         pcap_debug = 1;
 723 #else
 724                         extern int yydebug;
 725                         yydebug = 1;
 726 #endif
 727                         }
 728                         break;
 729 #endif
 730                 case 'Z':
 731                         if (optarg) {
 732                                 username = strdup(optarg);
 733                         }
 734                         else {
 735                                 usage();
 736                                 /* NOTREACHED */
 737                         }
 738                         break;
 739
 740                 default:
 741                         usage();
 742                         /* NOTREACHED */
 743                 }
 744
 745         switch (tflag) {
 746
 747         case 0: /* Default */
 748         case 4: /* Default + Date*/
 749                 thiszone = gmt2local(0);
 750                 break;
 751
 752         case 1: /* No time stamp */
 753         case 2: /* Unix timeval style */
 754         case 3: /* Microseconds since previous packet */
 755                 break;
 756
 757         default: /* Not supported */
 758                 error("only -t, -tt, -ttt, and -tttt are supported");
 759                 break;
 760         }
 761
 762 #ifdef WITH_CHROOT
 763         /* if run as root, prepare for chrooting */
 764         if (getuid() == 0 || geteuid() == 0) {
 765                 /* future extensibility for cmd-line arguments */
 766                 if (!chroot_dir)
 767                         chroot_dir = WITH_CHROOT;
 768         }
 769 #endif
 770
 771 #ifdef WITH_USER
 772         /* if run as root, prepare for dropping root privileges */
 773         if (getuid() == 0 || geteuid() == 0) {
 774                 /* Run with '-Z root' to restore old behaviour */
 775                 if (!username)
 776                         username = WITH_USER;
 777         }
 778 #endif
 779
 780         if (RFileName != NULL) {
 781                 int dlt;
 782                 const char *dlt_name;
 783
 784 #ifndef WIN32
 785                 /*
 786                  * We don't need network access, so relinquish any set-UID
 787                  * or set-GID privileges we have (if any).
 788                  *
 789                  * We do *not* want set-UID privileges when opening a
 790                  * trace file, as that might let the user read other
 791                  * people's trace files (especially if we're set-UID
 792                  * root).
 793                  */
 794                 if (setgid(getgid()) != 0 || setuid(getuid()) != 0 )
 795                         fprintf(stderr, "Warning: setgid/setuid failed !\n");
 796 #endif /* WIN32 */
 797                 pd = pcap_open_offline(RFileName, ebuf);
 798                 if (pd == NULL)
 799                         error("%s", ebuf);
 800                 dlt = pcap_datalink(pd);
 801                 dlt_name = pcap_datalink_val_to_name(dlt);
 802                 if (dlt_name == NULL) {
 803                         fprintf(stderr, "reading from file %s, link-type %u\n",
 804                             RFileName, dlt);
 805                 } else {
 806                         fprintf(stderr,
 807                             "reading from file %s, link-type %s (%s)\n",
 808                             RFileName, dlt_name,
 809                             pcap_datalink_val_to_description(dlt));
 810                 }
 811                 localnet = 0;
 812                 netmask = 0;
 813                 if (fflag != 0)
 814                         error("-f and -r options are incompatible");
 815         } else {
 816                 if (device == NULL) {
 817                         device = pcap_lookupdev(ebuf);
 818                         if (device == NULL)
 819                                 error("%s", ebuf);
 820                 }
 821 #ifdef WIN32
 822                 if(strlen(device) == 1) //we assume that an ASCII string is always longer than 1 char
 823                 {                                               //a Unicode string has a \0 as second byte (so strlen() is 1)
 824                         fprintf(stderr, "%s: listening on %ws\n", program_name, device);
 825                 }
 826                 else
 827                 {
 828                         fprintf(stderr, "%s: listening on %s\n", program_name, device);
 829                 }
 830
 831                 fflush(stderr);
 832 #endif /* WIN32 */
 833                 *ebuf = '\0';
 834                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 835                 if (pd == NULL)
 836                         error("%s", ebuf);
 837                 else if (*ebuf)
 838                         warning("%s", ebuf);
 839                 /*
 840                  * Let user own process after socket has been opened.
 841                  */
 842 #ifndef WIN32
 843                 if (setgid(getgid()) != 0 || setuid(getuid()) != 0)
 844                         fprintf(stderr, "Warning: setgid/setuid failed !\n");
 845 #endif /* WIN32 */
 846 #ifdef WIN32
 847                 if(UserBufferSize != 1000000)
 848                         if(pcap_setbuff(pd, UserBufferSize)==-1){
 849                                 error("%s", pcap_geterr(pd));
 850                         }
 851 #endif /* WIN32 */
 852                 if (Lflag)
 853                         show_dlts_and_exit(pd);
 854                 if (gndo->ndo_dlt >= 0) {
 855 #ifdef HAVE_PCAP_SET_DATALINK
 856                         if (pcap_set_datalink(pd, gndo->ndo_dlt) < 0)
 857                                 error("%s", pcap_geterr(pd));
 858 #else
 859                         /*
 860                          * We don't actually support changing the
 861                          * data link type, so we only let them
 862                          * set it to what it already is.
 863                          */
 864                         if (gndo->ndo_dlt != pcap_datalink(pd)) {
 865                                 error("%s is not one of the DLTs supported by this device\n",
 866                                       gndo->ndo_dltname);
 867                         }
 868 #endif
 869                         (void)fprintf(stderr, "%s: data link type %s\n",
 870                                       program_name, gndo->ndo_dltname);
 871                         (void)fflush(stderr);
 872                 }
 873                 i = pcap_snapshot(pd);
 874                 if (snaplen < i) {
 875                         warning("snaplen raised from %d to %d", snaplen, i);
 876                         snaplen = i;
 877                 }
 878                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 879                         localnet = 0;
 880                         netmask = 0;
 881                         warning("%s", ebuf);
 882                 }
 883         }
 884         if (infile)
 885                 cmdbuf = read_infile(infile);
 886         else
 887                 cmdbuf = copy_argv(&argv[optind]);
 888
 889         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 890                 error("%s", pcap_geterr(pd));
 891         if (dflag) {
 892                 bpf_dump(&fcode, dflag);
 893                 pcap_close(pd);
 894                 exit(0);
 895         }
 896         init_addrtoname(localnet, netmask);
 897
 898 #ifndef WIN32
 899         (void)setsignal(SIGPIPE, cleanup);
 900 #endif /* WIN32 */
 901         (void)setsignal(SIGTERM, cleanup);
 902         (void)setsignal(SIGINT, cleanup);
 903         /* Cooperate with nohup(1) */
 904 #ifndef WIN32
 905         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 906                 (void)setsignal(SIGHUP, oldhandler);
 907 #endif /* WIN32 */
 908
 909         if (pcap_setfilter(pd, &fcode) < 0)
 910                 error("%s", pcap_geterr(pd));
 911         if (WFileName) {
 912                 pcap_dumper_t *p;
 913
 914                 WFileNameAlt = (char *)malloc(strlen(WFileName) + MAX_CFLAG_CHARS + 1);
 915                 if (WFileNameAlt == NULL)
 916                         error("malloc of WFileNameAlt");
 917                 MakeFilename(WFileNameAlt, WFileName, 0, WflagChars);
 918                 p = pcap_dump_open(pd, WFileNameAlt);
 919                 if (p == NULL)
 920                         error("%s", pcap_geterr(pd));
 921                 if (Cflag != 0) {
 922                         callback = dump_packet_and_trunc;
 923                         dumpinfo.WFileName = WFileName;
 924                         dumpinfo.pd = pd;
 925                         dumpinfo.p = p;
 926                         pcap_userdata = (u_char *)&dumpinfo;
 927                 } else {
 928                         callback = dump_packet;
 929                         pcap_userdata = (u_char *)p;
 930                 }
 931         } else {
 932                 type = pcap_datalink(pd);
 933                 printinfo.printer = lookup_printer(type);
 934                 if (printinfo.printer == NULL) {
 935                         gndo->ndo_dltname = pcap_datalink_val_to_name(type);
 936                         if (gndo->ndo_dltname != NULL)
 937                                 error("unsupported data link type %s",
 938                                       gndo->ndo_dltname);
 939                         else
 940                                 error("unsupported data link type %d", type);
 941                 }
 942                 callback = print_packet;
 943                 pcap_userdata = (u_char *)&printinfo;
 944         }
 945 #ifndef WIN32
 946         /*
 947          * We cannot do this earlier, because we want to be able to open
 948          * the file (if done) for writing before giving up permissions.
 949          */
 950         if (getuid() == 0 || geteuid() == 0) {
 951                 if (username || chroot_dir)
 952                         droproot(username, chroot_dir);
 953         }
 954 #endif /* WIN32 */
 955 #ifdef SIGINFO
 956         (void)setsignal(SIGINFO, requestinfo);
 957 #endif
 958
 959         if (vflag > 0 && WFileName) {
 960                 /*
 961                  * When capturing to a file, "-v" means tcpdump should,
 962                  * every 10 secodns, "v"erbosely report the number of
 963                  * packets captured.
 964                  */
 965 #ifdef USE_WIN32_MM_TIMER
 966                 /* call verbose_stats_dump() each 1000 +/-100msec */
 967                 timer_id = timeSetEvent(1000, 100, verbose_stats_dump, 0, TIME_PERIODIC);
 968                 setvbuf(stderr, NULL, _IONBF, 0);
 969 #elif defined(HAVE_ALARM)
 970                 (void)setsignal(SIGALRM, verbose_stats_dump);
 971                 alarm(1);
 972 #endif
 973         }
 974
 975 #ifndef WIN32
 976         if (RFileName == NULL) {
 977                 int dlt;
 978                 const char *dlt_name;
 979
 980                 if (!vflag && !WFileName) {
 981                         (void)fprintf(stderr,
 982                             "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
 983                             program_name);
 984                 } else
 985                         (void)fprintf(stderr, "%s: ", program_name);
 986                 dlt = pcap_datalink(pd);
 987                 dlt_name = pcap_datalink_val_to_name(dlt);
 988                 if (dlt_name == NULL) {
 989                         (void)fprintf(stderr, "listening on %s, link-type %u, capture size %u bytes\n",
 990                             device, dlt, snaplen);
 991                 } else {
 992                         (void)fprintf(stderr, "listening on %s, link-type %s (%s), capture size %u bytes\n",
 993                             device, dlt_name,
 994                             pcap_datalink_val_to_description(dlt), snaplen);
 995                 }
 996                 (void)fflush(stderr);
 997         }
 998 #endif /* WIN32 */
 999         status = pcap_loop(pd, cnt, callback, pcap_userdata);
1000         if (WFileName == NULL) {
1001                 /*
1002                  * We're printing packets.  Flush the printed output,
1003                  * so it doesn't get intermingled with error output.
1004                  */
1005                 if (status == -2) {
1006                         /*
1007                          * We got interrupted, so perhaps we didn't
1008                          * manage to finish a line we were printing.
1009                          * Print an extra newline, just in case.
1010                          */
1011                         putchar('\n');
1012                 }
1013                 (void)fflush(stdout);
1014         }
1015         if (status == -1) {
1016                 /*
1017                  * Error.  Report it.
1018                  */
1019                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
1020                     program_name, pcap_geterr(pd));
1021         }
1022         if (RFileName == NULL) {
1023                 /*
1024                  * We're doing a live capture.  Report the capture
1025                  * statistics.
1026                  */
1027                 info(1);
1028         }
1029         pcap_close(pd);
1030         exit(status == -1 ? 1 : 0);
1031 }
1032
1033 /* make a clean exit on interrupts */
1034 static RETSIGTYPE
1035 cleanup(int signo _U_)
1036 {
1037 #ifdef USE_WIN32_MM_TIMER
1038         if (timer_id)
1039                 timeKillEvent(timer_id);
1040         timer_id = 0;
1041 #elif defined(HAVE_ALARM)
1042         alarm(0);
1043 #endif
1044
1045 #ifdef HAVE_PCAP_BREAKLOOP
1046         /*
1047          * We have "pcap_breakloop()"; use it, so that we do as little
1048          * as possible in the signal handler (it's probably not safe
1049          * to do anything with standard I/O streams in a signal handler -
1050          * the ANSI C standard doesn't say it is).
1051          */
1052         pcap_breakloop(pd);
1053 #else
1054         /*
1055          * We don't have "pcap_breakloop()"; this isn't safe, but
1056          * it's the best we can do.  Print the summary if we're
1057          * not reading from a savefile - i.e., if we're doing a
1058          * live capture - and exit.
1059          */
1060         if (pd != NULL && pcap_file(pd) == NULL) {
1061                 /*
1062                  * We got interrupted, so perhaps we didn't
1063                  * manage to finish a line we were printing.
1064                  * Print an extra newline, just in case.
1065                  */
1066                 putchar('\n');
1067                 (void)fflush(stdout);
1068                 info(1);
1069         }
1070         exit(0);
1071 #endif
1072 }
1073
1074 static void
1075 info(register int verbose)
1076 {
1077         struct pcap_stat stat;
1078
1079         if (pcap_stats(pd, &stat) < 0) {
1080                 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
1081                 return;
1082         }
1083
1084         if (!verbose)
1085                 fprintf(stderr, "%s: ", program_name);
1086
1087         (void)fprintf(stderr, "%u packets captured", packets_captured);
1088         if (!verbose)
1089                 fputs(", ", stderr);
1090         else
1091                 putc('\n', stderr);
1092         (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
1093         if (!verbose)
1094                 fputs(", ", stderr);
1095         else
1096                 putc('\n', stderr);
1097         (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
1098         infoprint = 0;
1099 }
1100
1101 static void
1102 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1103 {
1104         struct dump_info *dump_info;
1105         char *name;
1106
1107         ++packets_captured;
1108
1109         ++infodelay;
1110
1111         dump_info = (struct dump_info *)user;
1112
1113         /*
1114          * XXX - this won't prevent capture files from getting
1115          * larger than Cflag - the last packet written to the
1116          * file could put it over Cflag.
1117          */
1118         if (ftell((FILE *)dump_info->p) > Cflag) {
1119                 /*
1120                  * Close the current file and open a new one.
1121                  */
1122                 pcap_dump_close(dump_info->p);
1123                 Cflag_count++;
1124                 if (Wflag > 0) {
1125                         if (Cflag_count >= Wflag)
1126                                 Cflag_count = 0;
1127                 } else {
1128                         if (Cflag_count >= MAX_CFLAG)
1129                                 error("too many output files");
1130                 }
1131                 name = (char *)malloc(strlen(dump_info->WFileName) + MAX_CFLAG_CHARS + 1);
1132                 if (name == NULL)
1133                         error("dump_packet_and_trunc: malloc");
1134                 MakeFilename(name, dump_info->WFileName, Cflag_count, WflagChars);
1135                 dump_info->p = pcap_dump_open(dump_info->pd, name);
1136                 free(name);
1137                 if (dump_info->p == NULL)
1138                         error("%s", pcap_geterr(pd));
1139         }
1140
1141         pcap_dump((u_char *)dump_info->p, h, sp);
1142 #ifdef HAVE_PCAP_DUMP_FLUSH
1143         if (Uflag)
1144                 pcap_dump_flush(dump_info->p);
1145 #endif
1146
1147         --infodelay;
1148         if (infoprint)
1149                 info(0);
1150 }
1151
1152 static void
1153 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1154 {
1155         ++packets_captured;
1156
1157         ++infodelay;
1158
1159         pcap_dump(user, h, sp);
1160 #ifdef HAVE_PCAP_DUMP_FLUSH
1161         if (Uflag)
1162                 pcap_dump_flush((pcap_dumper_t *)user);
1163 #endif
1164
1165         --infodelay;
1166         if (infoprint)
1167                 info(0);
1168 }
1169
1170 static void
1171 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
1172 {
1173         struct print_info *print_info;
1174         u_int hdrlen;
1175
1176         ++packets_captured;
1177
1178         ++infodelay;
1179         ts_print(&h->ts);
1180
1181         print_info = (struct print_info *)user;
1182
1183         /*
1184          * Some printers want to check that they're not walking off the
1185          * end of the packet.
1186          * Rather than pass it all the way down, we set this global.
1187          */
1188         snapend = sp + h->caplen;
1189
1190         hdrlen = (*print_info->printer)(h, sp);
1191         if (xflag) {
1192                 /*
1193                  * Print the raw packet data.
1194                  */
1195                 if (xflag > 1) {
1196                         /*
1197                          * Include the link-layer header.
1198                          */
1199                         hex_print("\n\t", sp, h->caplen);
1200                 } else {
1201                         /*
1202                          * Don't include the link-layer header - and if
1203                          * we have nothing past the link-layer header,
1204                          * print nothing.
1205                          */
1206                         if (h->caplen > hdrlen)
1207                                 hex_print("\n\t", sp + hdrlen,
1208                                     h->caplen - hdrlen);
1209                 }
1210        } else if (Xflag) {
1211                 /*
1212                  * Print the raw packet data.
1213                  */
1214                 if (Xflag > 1) {
1215                         /*
1216                          * Include the link-layer header.
1217                          */
1218                         ascii_print("\n\t", sp, h->caplen);
1219                 } else {
1220                         /*
1221                          * Don't include the link-layer header - and if
1222                          * we have nothing past the link-layer header,
1223                          * print nothing.
1224                          */
1225                         if (h->caplen > hdrlen)
1226                                 ascii_print("\n\t", sp + hdrlen,
1227                                     h->caplen - hdrlen);
1228                 }
1229         }
1230
1231         putchar('\n');
1232
1233         --infodelay;
1234         if (infoprint)
1235                 info(0);
1236 }
1237
1238 #ifdef WIN32
1239         /*
1240          * XXX - there should really be libpcap calls to get the version
1241          * number as a string (the string would be generated from #defines
1242          * at run time, so that it's not generated from string constants
1243          * in the library, as, on many UNIX systems, those constants would
1244          * be statically linked into the application executable image, and
1245          * would thus reflect the version of libpcap on the system on
1246          * which the application was *linked*, not the system on which it's
1247          * *running*.
1248          *
1249          * That routine should be documented, unlike the "version[]"
1250          * string, so that UNIX vendors providing their own libpcaps
1251          * don't omit it (as a couple of vendors have...).
1252          *
1253          * Packet.dll should perhaps also export a routine to return the
1254          * version number of the Packet.dll code, to supply the
1255          * "Wpcap_version" information on Windows.
1256          */
1257         char WDversion[]="current-cvs.tcpdump.org";
1258 #if !defined(HAVE_GENERATED_VERSION)
1259         char version[]="current-cvs.tcpdump.org";
1260 #endif
1261         char pcap_version[]="current-cvs.tcpdump.org";
1262         char Wpcap_version[]="3.1";
1263 #endif
1264
1265 /*
1266  * By default, print the specified data out in hex.
1267  */
1268 void
1269 default_print(register const u_char *bp, register u_int length)
1270 {
1271         ascii_print("\n\t", bp, length); /* pass on lf and identation string */
1272 }
1273
1274 #ifdef SIGINFO
1275 RETSIGTYPE requestinfo(int signo _U_)
1276 {
1277         if (infodelay)
1278                 ++infoprint;
1279         else
1280                 info(0);
1281 }
1282 #endif
1283
1284 /*
1285  * Called once each second in verbose mode while dumping to file
1286  */
1287 #ifdef USE_WIN32_MM_TIMER
1288 void CALLBACK verbose_stats_dump (UINT timer_id _U_, UINT msg _U_, DWORD_PTR arg _U_,
1289                                   DWORD_PTR dw1 _U_, DWORD_PTR dw2 _U_)
1290 {
1291         struct pcap_stat stat;
1292
1293         if (infodelay == 0 && pcap_stats(pd, &stat) >= 0)
1294                 fprintf(stderr, "Got %u\r", packets_captured);
1295 }
1296 #elif defined(HAVE_ALARM)
1297 static void verbose_stats_dump(int sig _U_)
1298 {
1299         struct pcap_stat stat;
1300
1301         if (infodelay == 0 && pcap_stats(pd, &stat) >= 0)
1302                 fprintf(stderr, "Got %u\r", packets_captured);
1303         alarm(1);
1304 }
1305 #endif
1306
1307 static void
1308 usage(void)
1309 {
1310         extern char version[];
1311 #ifndef HAVE_PCAP_LIB_VERSION
1312 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
1313         extern char pcap_version[];
1314 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1315         static char pcap_version[] = "unknown";
1316 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1317 #endif /* HAVE_PCAP_LIB_VERSION */
1318
1319 #ifdef HAVE_PCAP_LIB_VERSION
1320 #ifdef WIN32
1321         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1322 #else /* WIN32 */
1323         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1324 #endif /* WIN32 */
1325         (void)fprintf(stderr, "%s\n",pcap_lib_version());
1326 #else /* HAVE_PCAP_LIB_VERSION */
1327 #ifdef WIN32
1328         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1329         (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1330 #else /* WIN32 */
1331         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1332         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1333 #endif /* WIN32 */
1334 #endif /* HAVE_PCAP_LIB_VERSION */
1335         (void)fprintf(stderr,
1336 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1337         (void)fprintf(stderr,
1338 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -M secret ]\n");
1339         (void)fprintf(stderr,
1340 "\t\t[ -r file ] [ -s snaplen ] [ -T type ] [ -w file ]\n");
1341         (void)fprintf(stderr,
1342 "\t\t[ -W filecount ] [ -y datalinktype ] [ -Z user ]\n");
1343         (void)fprintf(stderr,
1344 "\t\t[ expression ]\n");
1345         exit(1);
1346 }
1347
1348
1349
1350 /* VARARGS */
1351 static void
1352 ndo_error(netdissect_options *ndo _U_, const char *fmt, ...)
1353 {
1354         va_list ap;
1355
1356         (void)fprintf(stderr, "%s: ", program_name);
1357         va_start(ap, fmt);
1358         (void)vfprintf(stderr, fmt, ap);
1359         va_end(ap);
1360         if (*fmt) {
1361                 fmt += strlen(fmt);
1362                 if (fmt[-1] != '\n')
1363                         (void)fputc('\n', stderr);
1364         }
1365         exit(1);
1366         /* NOTREACHED */
1367 }
1368
1369 /* VARARGS */
1370 static void
1371 ndo_warning(netdissect_options *ndo _U_, const char *fmt, ...)
1372 {
1373         va_list ap;
1374
1375         (void)fprintf(stderr, "%s: WARNING: ", program_name);
1376         va_start(ap, fmt);
1377         (void)vfprintf(stderr, fmt, ap);
1378         va_end(ap);
1379         if (*fmt) {
1380                 fmt += strlen(fmt);
1381                 if (fmt[-1] != '\n')
1382                         (void)fputc('\n', stderr);
1383         }
1384 }
1385