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[] =
  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[] =
  33     "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.214 2003-08-08 09:47:45 risso Exp $ (LBL)";
  34 #endif
  35
  36 /*
  37  * tcpdump - monitor tcp/ip traffic on an ethernet.
  38  *
  39  * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
  40  * Mercilessly hacked and occasionally improved since then via the
  41  * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
  42  */
  43
  44 #ifdef HAVE_CONFIG_H
  45 #include "config.h"
  46 #endif
  47
  48 #include <tcpdump-stdinc.h>
  49
  50 #ifdef WIN32
  51 #include "getopt.h"
  52 #include "w32_fzs.h"
  53 extern int strcasecmp (const char *__s1, const char *__s2);
  54 extern int SIZE_BUF;
  55 #define off_t long
  56 #define uint UINT
  57 #endif /* WIN32 */
  58
  59 #include <pcap.h>
  60 #include <signal.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64
  65 #include "interface.h"
  66 #include "addrtoname.h"
  67 #include "machdep.h"
  68 #include "setsignal.h"
  69 #include "gmt2local.h"
  70 #include "pcap-missing.h"
  71
  72 int dflag;                      /* print filter code */
  73 int eflag;                      /* print ethernet header */
  74 int fflag;                      /* don't translate "foreign" IP address */
  75 int Lflag;                      /* list available data link types and exit */
  76 int nflag;                      /* leave addresses as numbers */
  77 int Nflag;                      /* remove domains from printed host names */
  78 int Oflag = 1;                  /* run filter code optimizer */
  79 int pflag;                      /* don't go promiscuous */
  80 int qflag;                      /* quick (shorter) output */
  81 int Rflag = 1;                  /* print sequence # field in AH/ESP*/
  82 int sflag = 0;                  /* use the libsmi to translate OIDs */
  83 int Sflag;                      /* print raw TCP sequence numbers */
  84 int tflag = 1;                  /* print packet arrival time */
  85 int Uflag = 0;                  /* "unbuffered" output of dump files */
  86 int uflag = 0;                  /* Print undecoded NFS handles */
  87 int vflag;                      /* verbose */
  88 int xflag;                      /* print packet in hex */
  89 int Xflag;                      /* print packet in ascii as well as hex */
  90 off_t Cflag = 0;                /* rotate dump files after this many bytes */
  91 int Aflag = 0;                  /* print packet only in ascii observing LF, CR, TAB, SPACE */
  92 int dlt = -1;           /* if != -1, ask libpcap for the DLT it names */
  93
  94 const char *dlt_name = NULL;
  95
  96 char *espsecret = NULL;         /* ESP secret key */
  97
  98 int packettype;
  99
 100 static int infodelay;
 101 static int infoprint;
 102
 103 char *program_name;
 104
 105 int32_t thiszone;               /* seconds offset from gmt to local time */
 106
 107 /* Forwards */
 108 static RETSIGTYPE cleanup(int);
 109 static void usage(void) __attribute__((noreturn));
 110 static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
 111
 112 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 113 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 114 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 115
 116 #ifdef SIGINFO
 117 RETSIGTYPE requestinfo(int);
 118 #endif
 119
 120 static void info(int);
 121
 122 /* Length of saved portion of packet. */
 123 int snaplen = DEFAULT_SNAPLEN;
 124
 125 typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);
 126
 127 struct printer {
 128         if_printer f;
 129         int type;
 130 };
 131
 132 static struct printer printers[] = {
 133         { arcnet_if_print,      DLT_ARCNET },
 134 #ifdef DLT_ARCNET_LINUX
 135         { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 136 #endif
 137         { ether_if_print,       DLT_EN10MB },
 138         { token_if_print,       DLT_IEEE802 },
 139 #ifdef DLT_LANE8023
 140         { lane_if_print,        DLT_LANE8023 },
 141 #endif
 142 #ifdef DLT_CIP
 143         { cip_if_print,         DLT_CIP },
 144 #endif
 145 #ifdef DLT_ATM_CLIP
 146         { cip_if_print,         DLT_ATM_CLIP },
 147 #endif
 148         { sl_if_print,          DLT_SLIP },
 149 #ifdef DLT_SLIP_BSDOS
 150         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 151 #endif
 152         { ppp_if_print,         DLT_PPP },
 153 #ifdef DLT_PPP_BSDOS
 154         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 155 #endif
 156         { fddi_if_print,        DLT_FDDI },
 157         { null_if_print,        DLT_NULL },
 158 #ifdef DLT_LOOP
 159         { null_if_print,        DLT_LOOP },
 160 #endif
 161         { raw_if_print,         DLT_RAW },
 162         { atm_if_print,         DLT_ATM_RFC1483 },
 163 #ifdef DLT_C_HDLC
 164         { chdlc_if_print,       DLT_C_HDLC },
 165 #endif
 166 #ifdef DLT_HDLC
 167         { chdlc_if_print,       DLT_HDLC },
 168 #endif
 169 #ifdef DLT_PPP_SERIAL
 170         { ppp_hdlc_if_print,    DLT_PPP_SERIAL },
 171 #endif
 172 #ifdef DLT_PPP_ETHER
 173         { pppoe_if_print,       DLT_PPP_ETHER },
 174 #endif
 175 #ifdef DLT_LINUX_SLL
 176         { sll_if_print,         DLT_LINUX_SLL },
 177 #endif
 178 #ifdef DLT_IEEE802_11
 179         { ieee802_11_if_print,  DLT_IEEE802_11},
 180 #endif
 181 #ifdef DLT_LTALK
 182         { ltalk_if_print,       DLT_LTALK },
 183 #endif
 184 #ifdef DLT_PFLOG
 185         { pflog_if_print,       DLT_PFLOG },
 186 #endif
 187 #ifdef DLT_FR
 188         { fr_if_print,          DLT_FR },
 189 #endif
 190 #ifdef DLT_FRELAY
 191         { fr_if_print,          DLT_FRELAY },
 192 #endif
 193 #ifdef DLT_SUNATM
 194         { sunatm_if_print,      DLT_SUNATM },
 195 #endif
 196 #ifdef DLT_IP_OVER_FC
 197         { ipfc_if_print,        DLT_IP_OVER_FC },
 198 #endif
 199 #ifdef DLT_PRISM_HEADER
 200         { prism_if_print,       DLT_PRISM_HEADER },
 201 #endif
 202 #ifdef DLT_IEEE802_11_RADIO
 203         { ieee802_11_radio_if_print,    DLT_IEEE802_11_RADIO },
 204 #endif
 205 #ifdef DLT_ENC
 206         { enc_if_print,         DLT_ENC },
 207 #endif
 208         { NULL,                 0 },
 209 };
 210
 211 static if_printer
 212 lookup_printer(int type)
 213 {
 214         struct printer *p;
 215
 216         for (p = printers; p->f; ++p)
 217                 if (type == p->type)
 218                         return p->f;
 219
 220         return NULL;
 221         /* NOTREACHED */
 222 }
 223
 224 static pcap_t *pd;
 225
 226 extern int optind;
 227 extern int opterr;
 228 extern char *optarg;
 229
 230 struct print_info {
 231         if_printer printer;
 232 };
 233
 234 struct dump_info {
 235         char    *WFileName;
 236         pcap_t  *pd;
 237         pcap_dumper_t *p;
 238 };
 239
 240 static void
 241 show_dlts_and_exit(pcap_t *pd)
 242 {
 243         int n_dlts;
 244         int *dlts = 0;
 245         const char *dlt_name;
 246
 247         n_dlts = pcap_list_datalinks(pd, &dlts);
 248         if (n_dlts < 0)
 249                 error("%s", pcap_geterr(pd));
 250         else if (n_dlts == 0 || !dlts)
 251                 error("No data link types.");
 252
 253         (void) fprintf(stderr, "Data link types (use option -y to set):\n");
 254
 255         while (--n_dlts >= 0) {
 256                 dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
 257                 if (dlt_name != NULL) {
 258                         (void) fprintf(stderr, "  %s", dlt_name);
 259
 260                         /*
 261                          * OK, does tcpdump handle that type?
 262                          */
 263                         if (lookup_printer(dlts[n_dlts]) == NULL)
 264                                 (void) fprintf(stderr, " (not supported)");
 265                         putchar('\n');
 266                 } else {
 267                         (void) fprintf(stderr, "  DLT %d (not supported)\n",
 268                             dlts[n_dlts]);
 269                 }
 270         }
 271         free(dlts);
 272         exit(0);
 273 }
 274
 275 /*
 276  * Set up flags that might or might not be supported depending on the
 277  * version of libpcap we're using.
 278  */
 279 #ifdef WIN32
 280 #define B_FLAG          "B:"
 281 #define B_FLAG_USAGE    " [ -B size ]"
 282 #else /* WIN32 */
 283 #define B_FLAG
 284 #define B_FLAG_USAGE
 285 #endif /* WIN32 */
 286
 287 #ifdef HAVE_PCAP_FINDALLDEVS
 288 #define D_FLAG  "D"
 289 #else
 290 #define D_FLAG
 291 #endif
 292
 293 #ifdef HAVE_PCAP_DUMP_FLUSH
 294 #define U_FLAG  "U"
 295 #else
 296 #define U_FLAG
 297 #endif
 298
 299 int
 300 main(int argc, char **argv)
 301 {
 302         register int cnt, op, i;
 303         bpf_u_int32 localnet, netmask;
 304         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
 305         pcap_handler callback;
 306         int type;
 307         struct bpf_program fcode;
 308 #ifndef WIN32
 309         RETSIGTYPE (*oldhandler)(int);
 310 #endif
 311         struct print_info printinfo;
 312         struct dump_info dumpinfo;
 313         u_char *pcap_userdata;
 314         char ebuf[PCAP_ERRBUF_SIZE];
 315 #ifdef HAVE_PCAP_FINDALLDEVS
 316         pcap_if_t *devpointer;
 317         int devnum;
 318 #endif
 319 #ifdef WIN32
 320         u_int UserBufferSize = 1000000;
 321         if(wsockinit() != 0) return 1;
 322 #endif /* WIN32 */
 323
 324         cnt = -1;
 325         device = NULL;
 326         infile = NULL;
 327         RFileName = NULL;
 328         WFileName = NULL;
 329         if ((cp = strrchr(argv[0], '/')) != NULL)
 330                 program_name = cp + 1;
 331         else
 332                 program_name = argv[0];
 333
 334         if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
 335                 error("%s", ebuf);
 336
 337 #ifdef LIBSMI
 338         smiInit("tcpdump");
 339 #endif
 340
 341         opterr = 0;
 342         while (
 343             (op = getopt(argc, argv, "aA" B_FLAG "c:C:d" D_FLAG "eE:fF:i:lLm:nNOpqr:Rs:StT:u" U_FLAG "vw:xXy:Y")) != -1)
 344                 switch (op) {
 345
 346                 case 'a':
 347                         /* compatibility for old -a */
 348                         break;
 349
 350                 case 'A':
 351                         ++xflag;
 352                         ++Xflag;
 353                         ++Aflag;
 354                         break;
 355
 356 #ifdef WIN32
 357                 case 'B':
 358                         UserBufferSize = atoi(optarg)*1024;
 359                         if (UserBufferSize < 0)
 360                                 error("invalid packet buffer size %s", optarg);
 361                         break;
 362 #endif /* WIN32 */
 363
 364                 case 'c':
 365                         cnt = atoi(optarg);
 366                         if (cnt <= 0)
 367                                 error("invalid packet count %s", optarg);
 368                         break;
 369
 370                 case 'C':
 371                         Cflag = atoi(optarg) * 1000000;
 372                         if (Cflag < 0)
 373                                 error("invalid file size %s", optarg);
 374                         break;
 375
 376                 case 'd':
 377                         ++dflag;
 378                         break;
 379
 380 #ifdef HAVE_PCAP_FINDALLDEVS
 381                 case 'D':
 382                         if (pcap_findalldevs(&devpointer, ebuf) < 0)
 383                                 error("%s", ebuf);
 384                         else {
 385                                 for (i = 0; devpointer != 0; i++) {
 386                                         printf("%d.%s", i+1, devpointer->name);
 387                                         if (devpointer->description != NULL)
 388                                                 printf(" (%s)", devpointer->description);
 389                                         printf("\n");
 390                                         devpointer = devpointer->next;
 391                                 }
 392                         }
 393                         return 0;
 394 #endif /* HAVE_PCAP_FINDALLDEVS */
 395
 396                 case 'L':
 397                         Lflag++;
 398                         break;
 399
 400                 case 'e':
 401                         ++eflag;
 402                         break;
 403
 404                 case 'E':
 405 #ifndef HAVE_LIBCRYPTO
 406                         warning("crypto code not compiled in");
 407 #endif
 408                         espsecret = optarg;
 409                         break;
 410
 411                 case 'f':
 412                         ++fflag;
 413                         break;
 414
 415                 case 'F':
 416                         infile = optarg;
 417                         break;
 418
 419                 case 'i':
 420                         if (optarg[0] == '0' && optarg[1] == 0)
 421                                 error("Invalid adapter index");
 422
 423 #ifdef HAVE_PCAP_FINDALLDEVS
 424                         /*
 425                          * If the argument is a number, treat it as
 426                          * an index into the list of adapters, as
 427                          * printed by "tcpdump -D".
 428                          *
 429                          * This should be OK on UNIX systems, as interfaces
 430                          * shouldn't have names that begin with digits.
 431                          * It can be useful on Windows, where more than
 432                          * one interface can have the same name.
 433                          */
 434                         if ((devnum = atoi(optarg)) != 0) {
 435                                 if (devnum < 0)
 436                                         error("Invalid adapter index");
 437
 438                                 if (pcap_findalldevs(&devpointer, ebuf) < 0)
 439                                         error("%s", ebuf);
 440                                 else {
 441                                         for (i = 0; i < devnum-1; i++){
 442                                                 devpointer = devpointer->next;
 443                                                 if (devpointer == NULL)
 444                                                         error("Invalid adapter index");
 445                                         }
 446                                 }
 447                                 device = devpointer->name;
 448                                 break;
 449                         }
 450 #endif /* HAVE_PCAP_FINDALLDEVS */
 451                         device = optarg;
 452                         break;
 453
 454                 case 'l':
 455 #ifdef HAVE_SETLINEBUF
 456                         setlinebuf(stdout);
 457 #else
 458                         setvbuf(stdout, NULL, _IOLBF, 0);
 459 #endif
 460                         break;
 461
 462                 case 'n':
 463                         ++nflag;
 464                         break;
 465
 466                 case 'N':
 467                         ++Nflag;
 468                         break;
 469
 470                 case 'm':
 471 #ifdef LIBSMI
 472                         if (smiLoadModule(optarg) == 0) {
 473                                 error("could not load MIB module %s", optarg);
 474                         }
 475                         sflag = 1;
 476 #else
 477                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 478                                       program_name, optarg);
 479                         (void)fprintf(stderr, "(no libsmi support)\n");
 480 #endif
 481
 482                 case 'O':
 483                         Oflag = 0;
 484                         break;
 485
 486                 case 'p':
 487                         ++pflag;
 488                         break;
 489
 490                 case 'q':
 491                         ++qflag;
 492                         break;
 493
 494                 case 'r':
 495                         RFileName = optarg;
 496                         break;
 497
 498                 case 'R':
 499                         Rflag = 0;
 500                         break;
 501
 502                 case 's': {
 503                         char *end;
 504
 505                         snaplen = strtol(optarg, &end, 0);
 506                         if (optarg == end || *end != '\0'
 507                             || snaplen < 0 || snaplen > 65535)
 508                                 error("invalid snaplen %s", optarg);
 509                         else if (snaplen == 0)
 510                                 snaplen = 65535;
 511                         break;
 512                 }
 513
 514                 case 'S':
 515                         ++Sflag;
 516                         break;
 517
 518                 case 't':
 519                         --tflag;
 520                         break;
 521
 522                 case 'T':
 523                         if (strcasecmp(optarg, "vat") == 0)
 524                                 packettype = PT_VAT;
 525                         else if (strcasecmp(optarg, "wb") == 0)
 526                                 packettype = PT_WB;
 527                         else if (strcasecmp(optarg, "rpc") == 0)
 528                                 packettype = PT_RPC;
 529                         else if (strcasecmp(optarg, "rtp") == 0)
 530                                 packettype = PT_RTP;
 531                         else if (strcasecmp(optarg, "rtcp") == 0)
 532                                 packettype = PT_RTCP;
 533                         else if (strcasecmp(optarg, "snmp") == 0)
 534                                 packettype = PT_SNMP;
 535                         else if (strcasecmp(optarg, "cnfp") == 0)
 536                                 packettype = PT_CNFP;
 537                         else if (strcasecmp(optarg, "tftp") == 0)
 538                                 packettype = PT_TFTP;
 539                         else if (strcasecmp(optarg, "aodv") == 0)
 540                                 packettype = PT_AODV;
 541                         else
 542                                 error("unknown packet type `%s'", optarg);
 543                         break;
 544
 545                 case 'u':
 546                         ++uflag;
 547                         break;
 548
 549 #ifdef HAVE_PCAP_DUMP_FLUSH
 550                 case 'U':
 551                         ++Uflag;
 552                         break;
 553 #endif
 554
 555                 case 'v':
 556                         ++vflag;
 557                         break;
 558
 559                 case 'w':
 560                         WFileName = optarg;
 561                         break;
 562
 563                 case 'x':
 564                         ++xflag;
 565                         break;
 566
 567                 case 'X':
 568                         ++xflag;
 569                         ++Xflag;
 570                         break;
 571
 572                 case 'y':
 573                         dlt_name = optarg;
 574                         dlt = pcap_datalink_name_to_val(dlt_name);
 575                         if (dlt < 0)
 576                                 error("invalid data link type %s", dlt_name);
 577                         break;
 578
 579 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
 580                 case 'Y':
 581                         {
 582                         /* Undocumented flag */
 583 #ifdef HAVE_PCAP_DEBUG
 584                         extern int pcap_debug;
 585                         pcap_debug = 1;
 586 #else
 587                         extern int yydebug;
 588                         yydebug = 1;
 589 #endif
 590                         }
 591                         break;
 592 #endif
 593                 default:
 594                         usage();
 595                         /* NOTREACHED */
 596                 }
 597
 598         if (tflag > 0)
 599                 thiszone = gmt2local(0);
 600
 601         if (RFileName != NULL) {
 602                 int dlt;
 603                 const char *dlt_name;
 604
 605 #ifndef WIN32
 606                 /*
 607                  * We don't need network access, so relinquish any set-UID
 608                  * or set-GID privileges we have (if any).
 609                  *
 610                  * We do *not* want set-UID privileges when opening a
 611                  * trace file, as that might let the user read other
 612                  * people's trace files (especially if we're set-UID
 613                  * root).
 614                  */
 615                 setuid(getuid());
 616 #endif /* WIN32 */
 617                 pd = pcap_open_offline(RFileName, ebuf);
 618                 if (pd == NULL)
 619                         error("%s", ebuf);
 620                 dlt = pcap_datalink(pd);
 621                 dlt_name = pcap_datalink_val_to_name(dlt);
 622                 if (dlt_name == NULL)
 623                         dlt_name = "???";
 624                 printf("reading from file %s, link-type %u (%s)\n",
 625                        RFileName, dlt, dlt_name);
 626                 localnet = 0;
 627                 netmask = 0;
 628                 if (fflag != 0)
 629                         error("-f and -r options are incompatible");
 630         } else {
 631                 if (device == NULL) {
 632                         device = pcap_lookupdev(ebuf);
 633                         if (device == NULL)
 634                                 error("%s", ebuf);
 635                 }
 636 #ifdef WIN32
 637                 if(IsTextUnicode(device,
 638                         wcslen((short*)device),                // Device always ends with a double \0, so this way to determine its
 639                                                                                                         // length should be always valid
 640                         NULL))
 641                 {
 642                         fprintf(stderr, "%s: listening on %ws\n", program_name, device);
 643                 }
 644                 else
 645                 {
 646                         fprintf(stderr, "%s: listening on %s\n", program_name, device);
 647                 }
 648
 649                 fflush(stderr);
 650 #endif /* WIN32 */
 651                 *ebuf = '\0';
 652                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 653                 if (pd == NULL)
 654                         error("%s", ebuf);
 655                 else if (*ebuf)
 656                         warning("%s", ebuf);
 657 #ifdef WIN32
 658                 if(UserBufferSize != 1000000)
 659                         if(pcap_setbuff(pd, UserBufferSize)==-1){
 660                                 error("%s", pcap_geterr(pd));
 661                         }
 662 #endif /* WIN32 */
 663                 if (Lflag)
 664                         show_dlts_and_exit(pd);
 665                 if (dlt >= 0) {
 666 #ifdef HAVE_PCAP_SET_DATALINK
 667                         if (pcap_set_datalink(pd, dlt) < 0)
 668                                 error("%s", pcap_geterr(pd));
 669 #else
 670                         /*
 671                          * We don't actually support changing the
 672                          * data link type, so we only let them
 673                          * set it to what it already is.
 674                          */
 675                         if (dlt != pcap_datalink(pd)) {
 676                                 error("%s is not one of the DLTs supported by this device\n",
 677                                     dlt_name);
 678                         }
 679 #endif
 680                         (void)fprintf(stderr, "%s: data link type %s\n",
 681                                       program_name, dlt_name);
 682                         (void)fflush(stderr);
 683                 }
 684                 i = pcap_snapshot(pd);
 685                 if (snaplen < i) {
 686                         warning("snaplen raised from %d to %d", snaplen, i);
 687                         snaplen = i;
 688                 }
 689                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 690                         localnet = 0;
 691                         netmask = 0;
 692                         warning("%s", ebuf);
 693                 }
 694                 /*
 695                  * Let user own process after socket has been opened.
 696                  */
 697 #ifndef WIN32
 698                 setuid(getuid());
 699 #endif /* WIN32 */
 700         }
 701         if (infile)
 702                 cmdbuf = read_infile(infile);
 703         else
 704                 cmdbuf = copy_argv(&argv[optind]);
 705
 706         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 707                 error("%s", pcap_geterr(pd));
 708         if (dflag) {
 709                 bpf_dump(&fcode, dflag);
 710                 pcap_close(pd);
 711                 exit(0);
 712         }
 713         init_addrtoname(localnet, netmask);
 714
 715 #ifndef WIN32
 716         (void)setsignal(SIGPIPE, cleanup);
 717 #endif /* WIN32 */
 718         (void)setsignal(SIGTERM, cleanup);
 719         (void)setsignal(SIGINT, cleanup);
 720         /* Cooperate with nohup(1) */
 721 #ifndef WIN32
 722         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 723                 (void)setsignal(SIGHUP, oldhandler);
 724 #endif /* WIN32 */
 725
 726         if (pcap_setfilter(pd, &fcode) < 0)
 727                 error("%s", pcap_geterr(pd));
 728         if (WFileName) {
 729                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 730                 if (p == NULL)
 731                         error("%s", pcap_geterr(pd));
 732                 if (Cflag != 0) {
 733                         callback = dump_packet_and_trunc;
 734                         dumpinfo.WFileName = WFileName;
 735                         dumpinfo.pd = pd;
 736                         dumpinfo.p = p;
 737                         pcap_userdata = (u_char *)&dumpinfo;
 738                 } else {
 739                         callback = dump_packet;
 740                         pcap_userdata = (u_char *)p;
 741                 }
 742         } else {
 743                 type = pcap_datalink(pd);
 744                 printinfo.printer = lookup_printer(type);
 745                 if (printinfo.printer == NULL) {
 746                         dlt_name = pcap_datalink_val_to_name(type);
 747                         if (dlt_name != NULL)
 748                                 error("unsupported data link type %s", dlt_name);
 749                         else
 750                                 error("unsupported data link type %d", type);
 751                 }
 752                 callback = print_packet;
 753                 pcap_userdata = (u_char *)&printinfo;
 754         }
 755 #ifdef SIGINFO
 756         (void)setsignal(SIGINFO, requestinfo);
 757 #endif
 758 #ifndef WIN32
 759         if (RFileName == NULL) {
 760                 int dlt;
 761                 const char *dlt_name;
 762
 763                 if (!vflag && !WFileName) {
 764                         (void)fprintf(stderr,
 765                             "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
 766                             program_name);
 767                 } else
 768                         (void)fprintf(stderr, "%s: ", program_name);
 769                 dlt = pcap_datalink(pd);
 770                 dlt_name = pcap_datalink_val_to_name(dlt);
 771                 if (dlt_name == NULL)
 772                         dlt_name = "???";
 773                 (void)fprintf(stderr, "listening on %s, link-type %u (%s), capture size %u bytes\n",
 774                     device, dlt, dlt_name, snaplen);
 775                 (void)fflush(stderr);
 776         }
 777 #endif /* WIN32 */
 778         if (pcap_loop(pd, cnt, callback, pcap_userdata) < 0) {
 779                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 780                     program_name, pcap_geterr(pd));
 781                 cleanup(0);
 782                 pcap_close(pd);
 783                 exit(1);
 784         }
 785         if (RFileName == NULL)
 786                 info(1);
 787         pcap_close(pd);
 788         exit(0);
 789 }
 790
 791 /* make a clean exit on interrupts */
 792 static RETSIGTYPE
 793 cleanup(int signo)
 794 {
 795
 796         /* Can't print the summary if reading from a savefile */
 797         if (pd != NULL && pcap_file(pd) == NULL) {
 798                 (void)fflush(stdout);
 799                 putc('\n', stderr);
 800                 info(1);
 801         }
 802         if (signo)
 803                 exit(0);
 804 }
 805
 806 static void
 807 info(register int verbose)
 808 {
 809         struct pcap_stat stat;
 810
 811         if (pcap_stats(pd, &stat) < 0) {
 812                 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
 813                 return;
 814         }
 815
 816         if (!verbose)
 817                 fprintf(stderr, "%s: ", program_name);
 818
 819         (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
 820         if (!verbose)
 821                 fputs(", ", stderr);
 822         else
 823                 putc('\n', stderr);
 824         (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
 825         infoprint = 0;
 826 }
 827
 828 static void
 829 reverse(char *s)
 830 {
 831         int i, j, c;
 832
 833         for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
 834                 c = s[i];
 835                 s[i] = s[j];
 836                 s[j] = c;
 837         }
 838 }
 839
 840
 841 static void
 842 swebitoa(unsigned int n, char *s)
 843 {
 844         unsigned int i;
 845
 846         i = 0;
 847         do {
 848                 s[i++] = n % 10 + '0';
 849         } while ((n /= 10) > 0);
 850
 851         s[i] = '\0';
 852         reverse(s);
 853 }
 854
 855 static void
 856 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 857 {
 858         struct dump_info *dump_info;
 859         static uint cnt = 2;
 860         char *name;
 861
 862         ++infodelay;
 863
 864         dump_info = (struct dump_info *)user;
 865
 866         /*
 867          * XXX - this won't prevent capture files from getting
 868          * larger than Cflag - the last packet written to the
 869          * file could put it over Cflag.
 870          */
 871         if (ftell((FILE *)dump_info->p) > Cflag) {
 872                 name = (char *) malloc(strlen(dump_info->WFileName) + 4);
 873                 if (name == NULL)
 874                         error("dump_packet_and_trunc: malloc");
 875                 strcpy(name, dump_info->WFileName);
 876                 swebitoa(cnt, name + strlen(dump_info->WFileName));
 877                 cnt++;
 878                 pcap_dump_close(dump_info->p);
 879                 dump_info->p = pcap_dump_open(dump_info->pd, name);
 880                 free(name);
 881                 if (dump_info->p == NULL)
 882                         error("%s", pcap_geterr(pd));
 883         }
 884
 885         pcap_dump((u_char *)dump_info->p, h, sp);
 886 #ifdef HAVE_PCAP_DUMP_FLUSH
 887         if (Uflag)
 888                 pcap_dump_flush(dump_info->p);
 889 #endif
 890
 891         --infodelay;
 892         if (infoprint)
 893                 info(0);
 894 }
 895
 896 static void
 897 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 898 {
 899         ++infodelay;
 900
 901         pcap_dump(user, h, sp);
 902 #ifdef HAVE_PCAP_DUMP_FLUSH
 903         if (Uflag)
 904                 pcap_dump_flush((pcap_dumper_t *)user);
 905 #endif
 906
 907         --infodelay;
 908         if (infoprint)
 909                 info(0);
 910 }
 911
 912 static void
 913 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 914 {
 915         struct print_info *print_info;
 916         u_int hdrlen;
 917
 918         ++infodelay;
 919         ts_print(&h->ts);
 920
 921         print_info = (struct print_info *)user;
 922
 923         /*
 924          * Some printers want to check that they're not walking off the
 925          * end of the packet.
 926          * Rather than pass it all the way down, we set this global.
 927          */
 928         snapend = sp + h->caplen;
 929
 930         hdrlen = (*print_info->printer)(h, sp);
 931         if (xflag) {
 932                 /*
 933                  * Print the raw packet data.
 934                  */
 935                 if (xflag > 1) {
 936                         /*
 937                          * Include the link-layer header.
 938                          */
 939                         default_print_unaligned(sp, h->caplen);
 940                 } else {
 941                         /*
 942                          * Don't include the link-layer header - and if
 943                          * we have nothing past the link-layer header,
 944                          * print nothing.
 945                          */
 946                         if (h->caplen > hdrlen)
 947                                 default_print_unaligned(sp + hdrlen,
 948                                     h->caplen - hdrlen);
 949                 }
 950         }
 951
 952         putchar('\n');
 953
 954         --infodelay;
 955         if (infoprint)
 956                 info(0);
 957 }
 958
 959 /* Like default_print() but data need not be aligned */
 960 void
 961 default_print_unaligned(register const u_char *cp, register u_int length)
 962 {
 963         register u_int i, s;
 964         register int nshorts;
 965
 966         if (Xflag) {
 967                 ascii_print(cp, length);
 968                 return;
 969         }
 970         nshorts = (u_int) length / sizeof(u_short);
 971         i = 0;
 972         while (--nshorts >= 0) {
 973                 if ((i++ % 8) == 0)
 974                         (void)printf("\n\t\t\t");
 975                 s = *cp++;
 976                 (void)printf(" %02x%02x", s, *cp++);
 977         }
 978         if (length & 1) {
 979                 if ((i % 8) == 0)
 980                         (void)printf("\n\t\t\t");
 981                 (void)printf(" %02x", *cp);
 982         }
 983 }
 984
 985 #ifdef WIN32
 986         /*
 987          * XXX - there should really be libpcap calls to get the version
 988          * number as a string (the string would be generated from #defines
 989          * at run time, so that it's not generated from string constants
 990          * in the library, as, on many UNIX systems, those constants would
 991          * be statically linked into the application executable image, and
 992          * would thus reflect the version of libpcap on the system on
 993          * which the application was *linked*, not the system on which it's
 994          * *running*.
 995          *
 996          * That routine should be documented, unlike the "version[]"
 997          * string, so that UNIX vendors providing their own libpcaps
 998          * don't omit it (as a couple of vendors have...).
 999          *
1000          * Packet.dll should perhaps also export a routine to return the
1001          * version number of the Packet.dll code, to supply the
1002          * "Wpcap_version" information on Windows.
1003          */
1004         char WDversion[]="current-cvs.tcpdump.org";
1005         char version[]="current-cvs.tcpdump.org";
1006         char pcap_version[]="current-cvs.tcpdump.org";
1007         char Wpcap_version[]="3.0 alpha";
1008 #endif
1009
1010 /*
1011  * By default, print the specified data out in hex.
1012  */
1013 void
1014 default_print(register const u_char *bp, register u_int length)
1015 {
1016         default_print_unaligned(bp, length);
1017 }
1018
1019 #ifdef SIGINFO
1020 RETSIGTYPE requestinfo(int signo _U_)
1021 {
1022         if (infodelay)
1023                 ++infoprint;
1024         else
1025                 info(0);
1026 }
1027 #endif
1028
1029 static void
1030 usage(void)
1031 {
1032         extern char version[];
1033 #ifndef HAVE_PCAP_LIB_VERSION
1034 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
1035         extern char pcap_version[];
1036 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1037         static char pcap_version[] = "unknown";
1038 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1039 #endif /* HAVE_PCAP_LIB_VERSION */
1040
1041 #ifdef HAVE_PCAP_LIB_VERSION
1042         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1043         (void)fprintf(stderr, "%s\n", pcap_lib_version());
1044 #else /* HAVE_PCAP_LIB_VERSION */
1045 #ifdef WIN32
1046         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1047         (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1048 #else /* WIN32 */
1049         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1050         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1051 #endif /* WIN32 */
1052 #endif /* HAVE_PCAP_LIB_VERSION */
1053         (void)fprintf(stderr,
1054 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1055         (void)fprintf(stderr,
1056 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
1057         (void)fprintf(stderr,
1058 "\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
1059         (void)fprintf(stderr,
1060 "\t\t[ expression ]\n");
1061         exit(1);
1062 }