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 1.213 2003-08-06 06:49:41 guy Exp $ (LBL)";
  34 #endif
  35
  36 /*
  37  * tcpdump - monitor tcp/ip traffic on an ethernet.
  38  *
  39  * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
  40  * Mercilessly hacked and occasionally improved since then via the
  41  * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
  42  */
  43
  44 #ifdef HAVE_CONFIG_H
  45 #include "config.h"
  46 #endif
  47
  48 #include <tcpdump-stdinc.h>
  49
  50 #ifdef WIN32
  51 #include "getopt.h"
  52 #include "w32_fzs.h"
  53 extern int strcasecmp (const char *__s1, const char *__s2);
  54 extern int SIZE_BUF;
  55 #define off_t long
  56 #define uint UINT
  57 #endif /* WIN32 */
  58
  59 #include <pcap.h>
  60 #include <signal.h>
  61 #include <stdio.h>
  62 #include <stdlib.h>
  63 #include <string.h>
  64
  65 #include "interface.h"
  66 #include "addrtoname.h"
  67 #include "machdep.h"
  68 #include "setsignal.h"
  69 #include "gmt2local.h"
  70 #include "pcap-missing.h"
  71
  72 int dflag;                      /* print filter code */
  73 int eflag;                      /* print ethernet header */
  74 int fflag;                      /* don't translate "foreign" IP address */
  75 int Lflag;                      /* list available data link types and exit */
  76 int nflag;                      /* leave addresses as numbers */
  77 int Nflag;                      /* remove domains from printed host names */
  78 int Oflag = 1;                  /* run filter code optimizer */
  79 int pflag;                      /* don't go promiscuous */
  80 int qflag;                      /* quick (shorter) output */
  81 int Rflag = 1;                  /* print sequence # field in AH/ESP*/
  82 int sflag = 0;                  /* use the libsmi to translate OIDs */
  83 int Sflag;                      /* print raw TCP sequence numbers */
  84 int tflag = 1;                  /* print packet arrival time */
  85 int Uflag = 0;                  /* "unbuffered" output of dump files */
  86 int uflag = 0;                  /* Print undecoded NFS handles */
  87 int vflag;                      /* verbose */
  88 int xflag;                      /* print packet in hex */
  89 int Xflag;                      /* print packet in ascii as well as hex */
  90 off_t Cflag = 0;                /* rotate dump files after this many bytes */
  91 int Aflag = 0;                  /* print packet only in ascii observing LF, CR, TAB, SPACE */
  92 int dlt = -1;           /* if != -1, ask libpcap for the DLT it names */
  93
  94 const char *dlt_name = NULL;
  95
  96 char *espsecret = NULL;         /* ESP secret key */
  97
  98 int packettype;
  99
 100 static int infodelay;
 101 static int infoprint;
 102
 103 char *program_name;
 104
 105 int32_t thiszone;               /* seconds offset from gmt to local time */
 106
 107 /* Forwards */
 108 static RETSIGTYPE cleanup(int);
 109 static void usage(void) __attribute__((noreturn));
 110 static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
 111
 112 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 113 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 114 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 115
 116 #ifdef SIGINFO
 117 RETSIGTYPE requestinfo(int);
 118 #endif
 119
 120 static void info(int);
 121
 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         DWORD dwVersion;
 321         DWORD dwWindowsMajorVersion;
 322         u_int UserBufferSize=1000000;
 323 #endif
 324
 325 #ifdef WIN32
 326         dwVersion=GetVersion();         /* get the OS version */
 327         dwWindowsMajorVersion =  (DWORD)(LOBYTE(LOWORD(dwVersion)));
 328         if(wsockinit()!=0) return 1;
 329 #endif /* WIN32 */
 330
 331         cnt = -1;
 332         device = NULL;
 333         infile = NULL;
 334         RFileName = NULL;
 335         WFileName = NULL;
 336         if ((cp = strrchr(argv[0], '/')) != NULL)
 337                 program_name = cp + 1;
 338         else
 339                 program_name = argv[0];
 340
 341         if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
 342                 error("%s", ebuf);
 343
 344 #ifdef LIBSMI
 345         smiInit("tcpdump");
 346 #endif
 347
 348         opterr = 0;
 349         while (
 350             (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)
 351                 switch (op) {
 352
 353                 case 'a':
 354                         /* compatibility for old -a */
 355                         break;
 356
 357                 case 'A':
 358                         ++xflag;
 359                         ++Xflag;
 360                         ++Aflag;
 361                         break;
 362
 363 #ifdef WIN32
 364                 case 'B':
 365                         UserBufferSize = atoi(optarg)*1024;
 366                         if (UserBufferSize < 0)
 367                                 error("invalid packet buffer size %s", optarg);
 368                         break;
 369 #endif /* WIN32 */
 370
 371                 case 'c':
 372                         cnt = atoi(optarg);
 373                         if (cnt <= 0)
 374                                 error("invalid packet count %s", optarg);
 375                         break;
 376
 377                 case 'C':
 378                         Cflag = atoi(optarg) * 1000000;
 379                         if (Cflag < 0)
 380                                 error("invalid file size %s", optarg);
 381                         break;
 382
 383                 case 'd':
 384                         ++dflag;
 385                         break;
 386
 387 #ifdef HAVE_PCAP_FINDALLDEVS
 388                 case 'D':
 389                         if (pcap_findalldevs(&devpointer, ebuf) < 0)
 390                                 error("%s", ebuf);
 391                         else {
 392                                 for (i = 0; devpointer != 0; i++) {
 393                                         printf("%d.%s", i+1, devpointer->name);
 394                                         if (devpointer->description != NULL)
 395                                                 printf(" (%s)", devpointer->description);
 396                                         printf("\n");
 397                                         devpointer = devpointer->next;
 398                                 }
 399                         }
 400                         return 0;
 401 #endif /* HAVE_PCAP_FINDALLDEVS */
 402
 403                 case 'L':
 404                         Lflag++;
 405                         break;
 406
 407                 case 'e':
 408                         ++eflag;
 409                         break;
 410
 411                 case 'E':
 412 #ifndef HAVE_LIBCRYPTO
 413                         warning("crypto code not compiled in");
 414 #endif
 415                         espsecret = optarg;
 416                         break;
 417
 418                 case 'f':
 419                         ++fflag;
 420                         break;
 421
 422                 case 'F':
 423                         infile = optarg;
 424                         break;
 425
 426                 case 'i':
 427                         if (optarg[0] == '0' && optarg[1] == 0)
 428                                 error("Invalid adapter index");
 429
 430 #ifdef HAVE_PCAP_FINDALLDEVS
 431                         /*
 432                          * If the argument is a number, treat it as
 433                          * an index into the list of adapters, as
 434                          * printed by "tcpdump -D".
 435                          *
 436                          * This should be OK on UNIX systems, as interfaces
 437                          * shouldn't have names that begin with digits.
 438                          * It can be useful on Windows, where more than
 439                          * one interface can have the same name.
 440                          */
 441                         if ((devnum = atoi(optarg)) != 0) {
 442                                 if (devnum < 0)
 443                                         error("Invalid adapter index");
 444
 445                                 if (pcap_findalldevs(&devpointer, ebuf) < 0)
 446                                         error("%s", ebuf);
 447                                 else {
 448                                         for (i = 0; i < devnum-1; i++){
 449                                                 devpointer = devpointer->next;
 450                                                 if (devpointer == NULL)
 451                                                         error("Invalid adapter index");
 452                                         }
 453                                 }
 454                                 device = devpointer->name;
 455                                 break;
 456                         }
 457 #endif /* HAVE_PCAP_FINDALLDEVS */
 458                         device = optarg;
 459                         break;
 460
 461                 case 'l':
 462 #ifdef HAVE_SETLINEBUF
 463                         setlinebuf(stdout);
 464 #else
 465                         setvbuf(stdout, NULL, _IOLBF, 0);
 466 #endif
 467                         break;
 468
 469                 case 'n':
 470                         ++nflag;
 471                         break;
 472
 473                 case 'N':
 474                         ++Nflag;
 475                         break;
 476
 477                 case 'm':
 478 #ifdef LIBSMI
 479                         if (smiLoadModule(optarg) == 0) {
 480                                 error("could not load MIB module %s", optarg);
 481                         }
 482                         sflag = 1;
 483 #else
 484                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 485                                       program_name, optarg);
 486                         (void)fprintf(stderr, "(no libsmi support)\n");
 487 #endif
 488
 489                 case 'O':
 490                         Oflag = 0;
 491                         break;
 492
 493                 case 'p':
 494                         ++pflag;
 495                         break;
 496
 497                 case 'q':
 498                         ++qflag;
 499                         break;
 500
 501                 case 'r':
 502                         RFileName = optarg;
 503                         break;
 504
 505                 case 'R':
 506                         Rflag = 0;
 507                         break;
 508
 509                 case 's': {
 510                         char *end;
 511
 512                         snaplen = strtol(optarg, &end, 0);
 513                         if (optarg == end || *end != '\0'
 514                             || snaplen < 0 || snaplen > 65535)
 515                                 error("invalid snaplen %s", optarg);
 516                         else if (snaplen == 0)
 517                                 snaplen = 65535;
 518                         break;
 519                 }
 520
 521                 case 'S':
 522                         ++Sflag;
 523                         break;
 524
 525                 case 't':
 526                         --tflag;
 527                         break;
 528
 529                 case 'T':
 530                         if (strcasecmp(optarg, "vat") == 0)
 531                                 packettype = PT_VAT;
 532                         else if (strcasecmp(optarg, "wb") == 0)
 533                                 packettype = PT_WB;
 534                         else if (strcasecmp(optarg, "rpc") == 0)
 535                                 packettype = PT_RPC;
 536                         else if (strcasecmp(optarg, "rtp") == 0)
 537                                 packettype = PT_RTP;
 538                         else if (strcasecmp(optarg, "rtcp") == 0)
 539                                 packettype = PT_RTCP;
 540                         else if (strcasecmp(optarg, "snmp") == 0)
 541                                 packettype = PT_SNMP;
 542                         else if (strcasecmp(optarg, "cnfp") == 0)
 543                                 packettype = PT_CNFP;
 544                         else if (strcasecmp(optarg, "tftp") == 0)
 545                                 packettype = PT_TFTP;
 546                         else if (strcasecmp(optarg, "aodv") == 0)
 547                                 packettype = PT_AODV;
 548                         else
 549                                 error("unknown packet type `%s'", optarg);
 550                         break;
 551
 552                 case 'u':
 553                         ++uflag;
 554                         break;
 555
 556 #ifdef HAVE_PCAP_DUMP_FLUSH
 557                 case 'U':
 558                         ++Uflag;
 559                         break;
 560 #endif
 561
 562                 case 'v':
 563                         ++vflag;
 564                         break;
 565
 566                 case 'w':
 567                         WFileName = optarg;
 568                         break;
 569
 570                 case 'x':
 571                         ++xflag;
 572                         break;
 573
 574                 case 'X':
 575                         ++xflag;
 576                         ++Xflag;
 577                         break;
 578
 579                 case 'y':
 580                         dlt_name = optarg;
 581                         dlt = pcap_datalink_name_to_val(dlt_name);
 582                         if (dlt < 0)
 583                                 error("invalid data link type %s", dlt_name);
 584                         break;
 585
 586 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
 587                 case 'Y':
 588                         {
 589                         /* Undocumented flag */
 590 #ifdef HAVE_PCAP_DEBUG
 591                         extern int pcap_debug;
 592                         pcap_debug = 1;
 593 #else
 594                         extern int yydebug;
 595                         yydebug = 1;
 596 #endif
 597                         }
 598                         break;
 599 #endif
 600                 default:
 601                         usage();
 602                         /* NOTREACHED */
 603                 }
 604
 605         if (tflag > 0)
 606                 thiszone = gmt2local(0);
 607
 608         if (RFileName != NULL) {
 609                 int dlt;
 610                 const char *dlt_name;
 611
 612 #ifndef WIN32
 613                 /*
 614                  * We don't need network access, so relinquish any set-UID
 615                  * or set-GID privileges we have (if any).
 616                  *
 617                  * We do *not* want set-UID privileges when opening a
 618                  * trace file, as that might let the user read other
 619                  * people's trace files (especially if we're set-UID
 620                  * root).
 621                  */
 622                 setuid(getuid());
 623 #endif /* WIN32 */
 624                 pd = pcap_open_offline(RFileName, ebuf);
 625                 if (pd == NULL)
 626                         error("%s", ebuf);
 627                 dlt = pcap_datalink(pd);
 628                 dlt_name = pcap_datalink_val_to_name(dlt);
 629                 if (dlt_name == NULL)
 630                         dlt_name = "???";
 631                 printf("reading from file %s, link-type %u (%s)\n",
 632                        RFileName, dlt, dlt_name);
 633                 localnet = 0;
 634                 netmask = 0;
 635                 if (fflag != 0)
 636                         error("-f and -r options are incompatible");
 637         } else {
 638                 if (device == NULL) {
 639                         device = pcap_lookupdev(ebuf);
 640                         if (device == NULL)
 641                                 error("%s", ebuf);
 642                 }
 643 #ifdef WIN32
 644                 PrintCapBegins(program_name,device);
 645 #endif /* WIN32 */
 646                 *ebuf = '\0';
 647                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 648                 if (pd == NULL)
 649                         error("%s", ebuf);
 650                 else if (*ebuf)
 651                         warning("%s", ebuf);
 652 #ifdef WIN32
 653                 if(UserBufferSize != 1000000)
 654                         if(pcap_setbuff(pd, UserBufferSize)==-1){
 655                                 error("%s", pcap_geterr(pd));
 656                         }
 657 #endif /* WIN32 */
 658                 if (Lflag)
 659                         show_dlts_and_exit(pd);
 660                 if (dlt >= 0) {
 661 #ifdef HAVE_PCAP_SET_DATALINK
 662                         if (pcap_set_datalink(pd, dlt) < 0)
 663                                 error("%s", pcap_geterr(pd));
 664 #else
 665                         /*
 666                          * We don't actually support changing the
 667                          * data link type, so we only let them
 668                          * set it to what it already is.
 669                          */
 670                         if (dlt != pcap_datalink(pd)) {
 671                                 error("%s is not one of the DLTs supported by this device\n",
 672                                     dlt_name);
 673                         }
 674 #endif
 675                         (void)fprintf(stderr, "%s: data link type %s\n",
 676                                       program_name, dlt_name);
 677                         (void)fflush(stderr);
 678                 }
 679                 i = pcap_snapshot(pd);
 680                 if (snaplen < i) {
 681                         warning("snaplen raised from %d to %d", snaplen, i);
 682                         snaplen = i;
 683                 }
 684                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 685                         localnet = 0;
 686                         netmask = 0;
 687                         warning("%s", ebuf);
 688                 }
 689                 /*
 690                  * Let user own process after socket has been opened.
 691                  */
 692 #ifndef WIN32
 693                 setuid(getuid());
 694 #endif /* WIN32 */
 695         }
 696         if (infile)
 697                 cmdbuf = read_infile(infile);
 698         else
 699                 cmdbuf = copy_argv(&argv[optind]);
 700
 701         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 702                 error("%s", pcap_geterr(pd));
 703         if (dflag) {
 704                 bpf_dump(&fcode, dflag);
 705                 pcap_close(pd);
 706                 exit(0);
 707         }
 708         init_addrtoname(localnet, netmask);
 709
 710 #ifndef WIN32
 711         (void)setsignal(SIGPIPE, cleanup);
 712 #endif /* WIN32 */
 713         (void)setsignal(SIGTERM, cleanup);
 714         (void)setsignal(SIGINT, cleanup);
 715         /* Cooperate with nohup(1) */
 716 #ifndef WIN32
 717         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 718                 (void)setsignal(SIGHUP, oldhandler);
 719 #endif /* WIN32 */
 720
 721         if (pcap_setfilter(pd, &fcode) < 0)
 722                 error("%s", pcap_geterr(pd));
 723         if (WFileName) {
 724                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 725                 if (p == NULL)
 726                         error("%s", pcap_geterr(pd));
 727                 if (Cflag != 0) {
 728                         callback = dump_packet_and_trunc;
 729                         dumpinfo.WFileName = WFileName;
 730                         dumpinfo.pd = pd;
 731                         dumpinfo.p = p;
 732                         pcap_userdata = (u_char *)&dumpinfo;
 733                 } else {
 734                         callback = dump_packet;
 735                         pcap_userdata = (u_char *)p;
 736                 }
 737         } else {
 738                 type = pcap_datalink(pd);
 739                 printinfo.printer = lookup_printer(type);
 740                 if (printinfo.printer == NULL) {
 741                         dlt_name = pcap_datalink_val_to_name(type);
 742                         if (dlt_name != NULL)
 743                                 error("unsupported data link type %s", dlt_name);
 744                         else
 745                                 error("unsupported data link type %d", type);
 746                 }
 747                 callback = print_packet;
 748                 pcap_userdata = (u_char *)&printinfo;
 749         }
 750 #ifdef SIGINFO
 751         (void)setsignal(SIGINFO, requestinfo);
 752 #endif
 753 #ifndef WIN32
 754         if (RFileName == NULL) {
 755                 int dlt;
 756                 const char *dlt_name;
 757
 758                 if (!vflag && !WFileName) {
 759                         (void)fprintf(stderr,
 760                             "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
 761                             program_name);
 762                 } else
 763                         (void)fprintf(stderr, "%s: ", program_name);
 764                 dlt = pcap_datalink(pd);
 765                 dlt_name = pcap_datalink_val_to_name(dlt);
 766                 if (dlt_name == NULL)
 767                         dlt_name = "???";
 768                 (void)fprintf(stderr, "listening on %s, link-type %u (%s), capture size %u bytes\n",
 769                     device, dlt, dlt_name, snaplen);
 770                 (void)fflush(stderr);
 771         }
 772 #endif /* WIN32 */
 773         if (pcap_loop(pd, cnt, callback, pcap_userdata) < 0) {
 774                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 775                     program_name, pcap_geterr(pd));
 776                 cleanup(0);
 777                 pcap_close(pd);
 778                 exit(1);
 779         }
 780         if (RFileName == NULL)
 781                 info(1);
 782         pcap_close(pd);
 783         exit(0);
 784 }
 785
 786 /* make a clean exit on interrupts */
 787 static RETSIGTYPE
 788 cleanup(int signo)
 789 {
 790
 791         /* Can't print the summary if reading from a savefile */
 792         if (pd != NULL && pcap_file(pd) == NULL) {
 793                 (void)fflush(stdout);
 794                 putc('\n', stderr);
 795                 info(1);
 796         }
 797         if (signo)
 798                 exit(0);
 799 }
 800
 801 static void
 802 info(register int verbose)
 803 {
 804         struct pcap_stat stat;
 805
 806         if (pcap_stats(pd, &stat) < 0) {
 807                 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
 808                 return;
 809         }
 810
 811         if (!verbose)
 812                 fprintf(stderr, "%s: ", program_name);
 813
 814         (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
 815         if (!verbose)
 816                 fputs(", ", stderr);
 817         else
 818                 putc('\n', stderr);
 819         (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
 820         infoprint = 0;
 821 }
 822
 823 static void
 824 reverse(char *s)
 825 {
 826         int i, j, c;
 827
 828         for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
 829                 c = s[i];
 830                 s[i] = s[j];
 831                 s[j] = c;
 832         }
 833 }
 834
 835
 836 static void
 837 swebitoa(unsigned int n, char *s)
 838 {
 839         unsigned int i;
 840
 841         i = 0;
 842         do {
 843                 s[i++] = n % 10 + '0';
 844         } while ((n /= 10) > 0);
 845
 846         s[i] = '\0';
 847         reverse(s);
 848 }
 849
 850 static void
 851 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 852 {
 853         struct dump_info *dump_info;
 854         static uint cnt = 2;
 855         char *name;
 856
 857         ++infodelay;
 858
 859         dump_info = (struct dump_info *)user;
 860
 861         /*
 862          * XXX - this won't prevent capture files from getting
 863          * larger than Cflag - the last packet written to the
 864          * file could put it over Cflag.
 865          */
 866         if (ftell((FILE *)dump_info->p) > Cflag) {
 867                 name = (char *) malloc(strlen(dump_info->WFileName) + 4);
 868                 if (name == NULL)
 869                         error("dump_packet_and_trunc: malloc");
 870                 strcpy(name, dump_info->WFileName);
 871                 swebitoa(cnt, name + strlen(dump_info->WFileName));
 872                 cnt++;
 873                 pcap_dump_close(dump_info->p);
 874                 dump_info->p = pcap_dump_open(dump_info->pd, name);
 875                 free(name);
 876                 if (dump_info->p == NULL)
 877                         error("%s", pcap_geterr(pd));
 878         }
 879
 880         pcap_dump((u_char *)dump_info->p, h, sp);
 881 #ifdef HAVE_PCAP_DUMP_FLUSH
 882         if (Uflag)
 883                 pcap_dump_flush(dump_info->p);
 884 #endif
 885
 886         --infodelay;
 887         if (infoprint)
 888                 info(0);
 889 }
 890
 891 static void
 892 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 893 {
 894         ++infodelay;
 895
 896         pcap_dump(user, h, sp);
 897 #ifdef HAVE_PCAP_DUMP_FLUSH
 898         if (Uflag)
 899                 pcap_dump_flush((pcap_dumper_t *)user);
 900 #endif
 901
 902         --infodelay;
 903         if (infoprint)
 904                 info(0);
 905 }
 906
 907 static void
 908 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 909 {
 910         struct print_info *print_info;
 911         u_int hdrlen;
 912
 913         ++infodelay;
 914         ts_print(&h->ts);
 915
 916         print_info = (struct print_info *)user;
 917
 918         /*
 919          * Some printers want to check that they're not walking off the
 920          * end of the packet.
 921          * Rather than pass it all the way down, we set this global.
 922          */
 923         snapend = sp + h->caplen;
 924
 925         hdrlen = (*print_info->printer)(h, sp);
 926         if (xflag) {
 927                 /*
 928                  * Print the raw packet data.
 929                  */
 930                 if (xflag > 1) {
 931                         /*
 932                          * Include the link-layer header.
 933                          */
 934                         default_print_unaligned(sp, h->caplen);
 935                 } else {
 936                         /*
 937                          * Don't include the link-layer header - and if
 938                          * we have nothing past the link-layer header,
 939                          * print nothing.
 940                          */
 941                         if (h->caplen > hdrlen)
 942                                 default_print_unaligned(sp + hdrlen,
 943                                     h->caplen - hdrlen);
 944                 }
 945         }
 946
 947         putchar('\n');
 948
 949         --infodelay;
 950         if (infoprint)
 951                 info(0);
 952 }
 953
 954 /* Like default_print() but data need not be aligned */
 955 void
 956 default_print_unaligned(register const u_char *cp, register u_int length)
 957 {
 958         register u_int i, s;
 959         register int nshorts;
 960
 961         if (Xflag) {
 962                 ascii_print(cp, length);
 963                 return;
 964         }
 965         nshorts = (u_int) length / sizeof(u_short);
 966         i = 0;
 967         while (--nshorts >= 0) {
 968                 if ((i++ % 8) == 0)
 969                         (void)printf("\n\t\t\t");
 970                 s = *cp++;
 971                 (void)printf(" %02x%02x", s, *cp++);
 972         }
 973         if (length & 1) {
 974                 if ((i % 8) == 0)
 975                         (void)printf("\n\t\t\t");
 976                 (void)printf(" %02x", *cp);
 977         }
 978 }
 979
 980 #ifdef WIN32
 981         /*
 982          * XXX - there should really be libpcap calls to get the version
 983          * number as a string (the string would be generated from #defines
 984          * at run time, so that it's not generated from string constants
 985          * in the library, as, on many UNIX systems, those constants would
 986          * be statically linked into the application executable image, and
 987          * would thus reflect the version of libpcap on the system on
 988          * which the application was *linked*, not the system on which it's
 989          * *running*.
 990          *
 991          * That routine should be documented, unlike the "version[]"
 992          * string, so that UNIX vendors providing their own libpcaps
 993          * don't omit it (as a couple of vendors have...).
 994          *
 995          * Packet.dll should perhaps also export a routine to return the
 996          * version number of the Packet.dll code, to supply the
 997          * "Wpcap_version" information on Windows.
 998          */
 999         char WDversion[]="current-cvs.tcpdump.org";
1000         char version[]="current-cvs.tcpdump.org";
1001         char pcap_version[]="current-cvs.tcpdump.org";
1002         char Wpcap_version[]="3.0 alpha";
1003 #endif
1004
1005 /*
1006  * By default, print the specified data out in hex.
1007  */
1008 void
1009 default_print(register const u_char *bp, register u_int length)
1010 {
1011         default_print_unaligned(bp, length);
1012 }
1013
1014 #ifdef SIGINFO
1015 RETSIGTYPE requestinfo(int signo _U_)
1016 {
1017         if (infodelay)
1018                 ++infoprint;
1019         else
1020                 info(0);
1021 }
1022 #endif
1023
1024 static void
1025 usage(void)
1026 {
1027         extern char version[];
1028 #ifndef HAVE_PCAP_LIB_VERSION
1029 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
1030         extern char pcap_version[];
1031 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1032         static char pcap_version[] = "unknown";
1033 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1034 #endif /* HAVE_PCAP_LIB_VERSION */
1035
1036 #ifdef HAVE_PCAP_LIB_VERSION
1037         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1038         (void)fprintf(stderr, "%s\n", pcap_lib_version());
1039 #else /* HAVE_PCAP_LIB_VERSION */
1040 #ifdef WIN32
1041         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1042         (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1043 #else /* WIN32 */
1044         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1045         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1046 #endif /* WIN32 */
1047 #endif /* HAVE_PCAP_LIB_VERSION */
1048         (void)fprintf(stderr,
1049 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1050         (void)fprintf(stderr,
1051 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
1052         (void)fprintf(stderr,
1053 "\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
1054         (void)fprintf(stderr,
1055 "\t\t[ expression ]\n");
1056         exit(1);
1057 }