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 1.216.2.4 2003-11-18 23:12:11 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 static u_int packets_captured;
 122
 123 /* Length of saved portion of packet. */
 124 int snaplen = DEFAULT_SNAPLEN;
 125
 126 typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);
 127
 128 struct printer {
 129         if_printer f;
 130         int type;
 131 };
 132
 133 static struct printer printers[] = {
 134         { arcnet_if_print,      DLT_ARCNET },
 135 #ifdef DLT_ARCNET_LINUX
 136         { arcnet_linux_if_print, DLT_ARCNET_LINUX },
 137 #endif
 138         { ether_if_print,       DLT_EN10MB },
 139         { token_if_print,       DLT_IEEE802 },
 140 #ifdef DLT_LANE8023
 141         { lane_if_print,        DLT_LANE8023 },
 142 #endif
 143 #ifdef DLT_CIP
 144         { cip_if_print,         DLT_CIP },
 145 #endif
 146 #ifdef DLT_ATM_CLIP
 147         { cip_if_print,         DLT_ATM_CLIP },
 148 #endif
 149         { sl_if_print,          DLT_SLIP },
 150 #ifdef DLT_SLIP_BSDOS
 151         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 152 #endif
 153         { ppp_if_print,         DLT_PPP },
 154 #ifdef DLT_PPP_BSDOS
 155         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 156 #endif
 157         { fddi_if_print,        DLT_FDDI },
 158         { null_if_print,        DLT_NULL },
 159 #ifdef DLT_LOOP
 160         { null_if_print,        DLT_LOOP },
 161 #endif
 162         { raw_if_print,         DLT_RAW },
 163         { atm_if_print,         DLT_ATM_RFC1483 },
 164 #ifdef DLT_C_HDLC
 165         { chdlc_if_print,       DLT_C_HDLC },
 166 #endif
 167 #ifdef DLT_HDLC
 168         { chdlc_if_print,       DLT_HDLC },
 169 #endif
 170 #ifdef DLT_PPP_SERIAL
 171         { ppp_hdlc_if_print,    DLT_PPP_SERIAL },
 172 #endif
 173 #ifdef DLT_PPP_ETHER
 174         { pppoe_if_print,       DLT_PPP_ETHER },
 175 #endif
 176 #ifdef DLT_LINUX_SLL
 177         { sll_if_print,         DLT_LINUX_SLL },
 178 #endif
 179 #ifdef DLT_IEEE802_11
 180         { ieee802_11_if_print,  DLT_IEEE802_11},
 181 #endif
 182 #ifdef DLT_LTALK
 183         { ltalk_if_print,       DLT_LTALK },
 184 #endif
 185 #ifdef DLT_PFLOG
 186         { pflog_if_print,       DLT_PFLOG },
 187 #endif
 188 #ifdef DLT_FR
 189         { fr_if_print,          DLT_FR },
 190 #endif
 191 #ifdef DLT_FRELAY
 192         { fr_if_print,          DLT_FRELAY },
 193 #endif
 194 #ifdef DLT_SUNATM
 195         { sunatm_if_print,      DLT_SUNATM },
 196 #endif
 197 #ifdef DLT_IP_OVER_FC
 198         { ipfc_if_print,        DLT_IP_OVER_FC },
 199 #endif
 200 #ifdef DLT_PRISM_HEADER
 201         { prism_if_print,       DLT_PRISM_HEADER },
 202 #endif
 203 #ifdef DLT_IEEE802_11_RADIO
 204         { ieee802_11_radio_if_print,    DLT_IEEE802_11_RADIO },
 205 #endif
 206 #ifdef DLT_ENC
 207         { enc_if_print,         DLT_ENC },
 208 #endif
 209         { NULL,                 0 },
 210 };
 211
 212 static if_printer
 213 lookup_printer(int type)
 214 {
 215         struct printer *p;
 216
 217         for (p = printers; p->f; ++p)
 218                 if (type == p->type)
 219                         return p->f;
 220
 221         return NULL;
 222         /* NOTREACHED */
 223 }
 224
 225 static pcap_t *pd;
 226
 227 extern int optind;
 228 extern int opterr;
 229 extern char *optarg;
 230
 231 struct print_info {
 232         if_printer printer;
 233 };
 234
 235 struct dump_info {
 236         char    *WFileName;
 237         pcap_t  *pd;
 238         pcap_dumper_t *p;
 239 };
 240
 241 static void
 242 show_dlts_and_exit(pcap_t *pd)
 243 {
 244         int n_dlts;
 245         int *dlts = 0;
 246         const char *dlt_name;
 247
 248         n_dlts = pcap_list_datalinks(pd, &dlts);
 249         if (n_dlts < 0)
 250                 error("%s", pcap_geterr(pd));
 251         else if (n_dlts == 0 || !dlts)
 252                 error("No data link types.");
 253
 254         (void) fprintf(stderr, "Data link types (use option -y to set):\n");
 255
 256         while (--n_dlts >= 0) {
 257                 dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
 258                 if (dlt_name != NULL) {
 259                         (void) fprintf(stderr, "  %s (%s)", dlt_name,
 260                             pcap_datalink_val_to_description(dlts[n_dlts]));
 261
 262                         /*
 263                          * OK, does tcpdump handle that type?
 264                          */
 265                         if (lookup_printer(dlts[n_dlts]) == NULL)
 266                                 (void) fprintf(stderr, " (not supported)");
 267                         putchar('\n');
 268                 } else {
 269                         (void) fprintf(stderr, "  DLT %d (not supported)\n",
 270                             dlts[n_dlts]);
 271                 }
 272         }
 273         free(dlts);
 274         exit(0);
 275 }
 276
 277 /*
 278  * Set up flags that might or might not be supported depending on the
 279  * version of libpcap we're using.
 280  */
 281 #ifdef WIN32
 282 #define B_FLAG          "B:"
 283 #define B_FLAG_USAGE    " [ -B size ]"
 284 #else /* WIN32 */
 285 #define B_FLAG
 286 #define B_FLAG_USAGE
 287 #endif /* WIN32 */
 288
 289 #ifdef HAVE_PCAP_FINDALLDEVS
 290 #define D_FLAG  "D"
 291 #else
 292 #define D_FLAG
 293 #endif
 294
 295 #ifdef HAVE_PCAP_DUMP_FLUSH
 296 #define U_FLAG  "U"
 297 #else
 298 #define U_FLAG
 299 #endif
 300
 301 int
 302 main(int argc, char **argv)
 303 {
 304         register int cnt, op, i;
 305         bpf_u_int32 localnet, netmask;
 306         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
 307         pcap_handler callback;
 308         int type;
 309         struct bpf_program fcode;
 310 #ifndef WIN32
 311         RETSIGTYPE (*oldhandler)(int);
 312 #endif
 313         struct print_info printinfo;
 314         struct dump_info dumpinfo;
 315         u_char *pcap_userdata;
 316         char ebuf[PCAP_ERRBUF_SIZE];
 317 #ifdef HAVE_PCAP_FINDALLDEVS
 318         pcap_if_t *devpointer;
 319         int devnum;
 320 #endif
 321         int status;
 322 #ifdef WIN32
 323         u_int UserBufferSize = 1000000;
 324         if(wsockinit() != 0) return 1;
 325 #endif /* WIN32 */
 326
 327         cnt = -1;
 328         device = NULL;
 329         infile = NULL;
 330         RFileName = NULL;
 331         WFileName = NULL;
 332         if ((cp = strrchr(argv[0], '/')) != NULL)
 333                 program_name = cp + 1;
 334         else
 335                 program_name = argv[0];
 336
 337         if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
 338                 error("%s", ebuf);
 339
 340 #ifdef LIBSMI
 341         smiInit("tcpdump");
 342 #endif
 343
 344         opterr = 0;
 345         while (
 346             (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)
 347                 switch (op) {
 348
 349                 case 'a':
 350                         /* compatibility for old -a */
 351                         break;
 352
 353                 case 'A':
 354                         ++xflag;
 355                         ++Xflag;
 356                         ++Aflag;
 357                         break;
 358
 359 #ifdef WIN32
 360                 case 'B':
 361                         UserBufferSize = atoi(optarg)*1024;
 362                         if (UserBufferSize < 0)
 363                                 error("invalid packet buffer size %s", optarg);
 364                         break;
 365 #endif /* WIN32 */
 366
 367                 case 'c':
 368                         cnt = atoi(optarg);
 369                         if (cnt <= 0)
 370                                 error("invalid packet count %s", optarg);
 371                         break;
 372
 373                 case 'C':
 374                         Cflag = atoi(optarg) * 1000000;
 375                         if (Cflag < 0)
 376                                 error("invalid file size %s", optarg);
 377                         break;
 378
 379                 case 'd':
 380                         ++dflag;
 381                         break;
 382
 383 #ifdef HAVE_PCAP_FINDALLDEVS
 384                 case 'D':
 385                         if (pcap_findalldevs(&devpointer, ebuf) < 0)
 386                                 error("%s", ebuf);
 387                         else {
 388                                 for (i = 0; devpointer != 0; i++) {
 389                                         printf("%d.%s", i+1, devpointer->name);
 390                                         if (devpointer->description != NULL)
 391                                                 printf(" (%s)", devpointer->description);
 392                                         printf("\n");
 393                                         devpointer = devpointer->next;
 394                                 }
 395                         }
 396                         return 0;
 397 #endif /* HAVE_PCAP_FINDALLDEVS */
 398
 399                 case 'L':
 400                         Lflag++;
 401                         break;
 402
 403                 case 'e':
 404                         ++eflag;
 405                         break;
 406
 407                 case 'E':
 408 #ifndef HAVE_LIBCRYPTO
 409                         warning("crypto code not compiled in");
 410 #endif
 411                         espsecret = optarg;
 412                         break;
 413
 414                 case 'f':
 415                         ++fflag;
 416                         break;
 417
 418                 case 'F':
 419                         infile = optarg;
 420                         break;
 421
 422                 case 'i':
 423                         if (optarg[0] == '0' && optarg[1] == 0)
 424                                 error("Invalid adapter index");
 425
 426 #ifdef HAVE_PCAP_FINDALLDEVS
 427                         /*
 428                          * If the argument is a number, treat it as
 429                          * an index into the list of adapters, as
 430                          * printed by "tcpdump -D".
 431                          *
 432                          * This should be OK on UNIX systems, as interfaces
 433                          * shouldn't have names that begin with digits.
 434                          * It can be useful on Windows, where more than
 435                          * one interface can have the same name.
 436                          */
 437                         if ((devnum = atoi(optarg)) != 0) {
 438                                 if (devnum < 0)
 439                                         error("Invalid adapter index");
 440
 441                                 if (pcap_findalldevs(&devpointer, ebuf) < 0)
 442                                         error("%s", ebuf);
 443                                 else {
 444                                         for (i = 0; i < devnum-1; i++){
 445                                                 devpointer = devpointer->next;
 446                                                 if (devpointer == NULL)
 447                                                         error("Invalid adapter index");
 448                                         }
 449                                 }
 450                                 device = devpointer->name;
 451                                 break;
 452                         }
 453 #endif /* HAVE_PCAP_FINDALLDEVS */
 454                         device = optarg;
 455                         break;
 456
 457                 case 'l':
 458 #ifdef WIN32
 459                         /*
 460                          * _IOLBF is the same as _IOFBF in Microsoft's C
 461                          * libraries; the only alternative they offer
 462                          * is _IONBF.
 463                          *
 464                          * XXX - this should really be checking for MSVC++,
 465                          * not WIN32, if, for example, MinGW has its own
 466                          * C library that is more UNIX-compatible.
 467                          */
 468                         setvbuf(stdout, NULL, _IONBF, 0);
 469 #else /* WIN32 */
 470 #ifdef HAVE_SETLINEBUF
 471                         setlinebuf(stdout);
 472 #else
 473                         setvbuf(stdout, NULL, _IOLBF, 0);
 474 #endif
 475 #endif /* WIN32 */
 476                         break;
 477
 478                 case 'n':
 479                         ++nflag;
 480                         break;
 481
 482                 case 'N':
 483                         ++Nflag;
 484                         break;
 485
 486                 case 'm':
 487 #ifdef LIBSMI
 488                         if (smiLoadModule(optarg) == 0) {
 489                                 error("could not load MIB module %s", optarg);
 490                         }
 491                         sflag = 1;
 492 #else
 493                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 494                                       program_name, optarg);
 495                         (void)fprintf(stderr, "(no libsmi support)\n");
 496 #endif
 497
 498                 case 'O':
 499                         Oflag = 0;
 500                         break;
 501
 502                 case 'p':
 503                         ++pflag;
 504                         break;
 505
 506                 case 'q':
 507                         ++qflag;
 508                         break;
 509
 510                 case 'r':
 511                         RFileName = optarg;
 512                         break;
 513
 514                 case 'R':
 515                         Rflag = 0;
 516                         break;
 517
 518                 case 's': {
 519                         char *end;
 520
 521                         snaplen = strtol(optarg, &end, 0);
 522                         if (optarg == end || *end != '\0'
 523                             || snaplen < 0 || snaplen > 65535)
 524                                 error("invalid snaplen %s", optarg);
 525                         else if (snaplen == 0)
 526                                 snaplen = 65535;
 527                         break;
 528                 }
 529
 530                 case 'S':
 531                         ++Sflag;
 532                         break;
 533
 534                 case 't':
 535                         --tflag;
 536                         break;
 537
 538                 case 'T':
 539                         if (strcasecmp(optarg, "vat") == 0)
 540                                 packettype = PT_VAT;
 541                         else if (strcasecmp(optarg, "wb") == 0)
 542                                 packettype = PT_WB;
 543                         else if (strcasecmp(optarg, "rpc") == 0)
 544                                 packettype = PT_RPC;
 545                         else if (strcasecmp(optarg, "rtp") == 0)
 546                                 packettype = PT_RTP;
 547                         else if (strcasecmp(optarg, "rtcp") == 0)
 548                                 packettype = PT_RTCP;
 549                         else if (strcasecmp(optarg, "snmp") == 0)
 550                                 packettype = PT_SNMP;
 551                         else if (strcasecmp(optarg, "cnfp") == 0)
 552                                 packettype = PT_CNFP;
 553                         else if (strcasecmp(optarg, "tftp") == 0)
 554                                 packettype = PT_TFTP;
 555                         else if (strcasecmp(optarg, "aodv") == 0)
 556                                 packettype = PT_AODV;
 557                         else
 558                                 error("unknown packet type `%s'", optarg);
 559                         break;
 560
 561                 case 'u':
 562                         ++uflag;
 563                         break;
 564
 565 #ifdef HAVE_PCAP_DUMP_FLUSH
 566                 case 'U':
 567                         ++Uflag;
 568                         break;
 569 #endif
 570
 571                 case 'v':
 572                         ++vflag;
 573                         break;
 574
 575                 case 'w':
 576                         WFileName = optarg;
 577                         break;
 578
 579                 case 'x':
 580                         ++xflag;
 581                         break;
 582
 583                 case 'X':
 584                         ++xflag;
 585                         ++Xflag;
 586                         break;
 587
 588                 case 'y':
 589                         dlt_name = optarg;
 590                         dlt = pcap_datalink_name_to_val(dlt_name);
 591                         if (dlt < 0)
 592                                 error("invalid data link type %s", dlt_name);
 593                         break;
 594
 595 #if defined(HAVE_PCAP_DEBUG) || defined(HAVE_YYDEBUG)
 596                 case 'Y':
 597                         {
 598                         /* Undocumented flag */
 599 #ifdef HAVE_PCAP_DEBUG
 600                         extern int pcap_debug;
 601                         pcap_debug = 1;
 602 #else
 603                         extern int yydebug;
 604                         yydebug = 1;
 605 #endif
 606                         }
 607                         break;
 608 #endif
 609                 default:
 610                         usage();
 611                         /* NOTREACHED */
 612                 }
 613
 614         if (tflag > 0)
 615                 thiszone = gmt2local(0);
 616
 617         if (RFileName != NULL) {
 618                 int dlt;
 619                 const char *dlt_name;
 620
 621 #ifndef WIN32
 622                 /*
 623                  * We don't need network access, so relinquish any set-UID
 624                  * or set-GID privileges we have (if any).
 625                  *
 626                  * We do *not* want set-UID privileges when opening a
 627                  * trace file, as that might let the user read other
 628                  * people's trace files (especially if we're set-UID
 629                  * root).
 630                  */
 631                 setuid(getuid());
 632 #endif /* WIN32 */
 633                 pd = pcap_open_offline(RFileName, ebuf);
 634                 if (pd == NULL)
 635                         error("%s", ebuf);
 636                 dlt = pcap_datalink(pd);
 637                 dlt_name = pcap_datalink_val_to_name(dlt);
 638                 if (dlt_name == NULL) {
 639                         printf("reading from file %s, link-type %u\n",
 640                             RFileName, dlt);
 641                 } else {
 642                         printf("reading from file %s, link-type %s (%s)\n",
 643                             RFileName, dlt_name,
 644                             pcap_datalink_val_to_description(dlt));
 645                 }
 646                 localnet = 0;
 647                 netmask = 0;
 648                 if (fflag != 0)
 649                         error("-f and -r options are incompatible");
 650         } else {
 651                 if (device == NULL) {
 652                         device = pcap_lookupdev(ebuf);
 653                         if (device == NULL)
 654                                 error("%s", ebuf);
 655                 }
 656 #ifdef WIN32
 657                 if(IsTextUnicode(device,
 658                         wcslen((short*)device),                // Device always ends with a double \0, so this way to determine its
 659                                                                                                         // length should be always valid
 660                         NULL))
 661                 {
 662                         fprintf(stderr, "%s: listening on %ws\n", program_name, device);
 663                 }
 664                 else
 665                 {
 666                         fprintf(stderr, "%s: listening on %s\n", program_name, device);
 667                 }
 668
 669                 fflush(stderr);
 670 #endif /* WIN32 */
 671                 *ebuf = '\0';
 672                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 673                 if (pd == NULL)
 674                         error("%s", ebuf);
 675                 else if (*ebuf)
 676                         warning("%s", ebuf);
 677 #ifdef WIN32
 678                 if(UserBufferSize != 1000000)
 679                         if(pcap_setbuff(pd, UserBufferSize)==-1){
 680                                 error("%s", pcap_geterr(pd));
 681                         }
 682 #endif /* WIN32 */
 683                 if (Lflag)
 684                         show_dlts_and_exit(pd);
 685                 if (dlt >= 0) {
 686 #ifdef HAVE_PCAP_SET_DATALINK
 687                         if (pcap_set_datalink(pd, dlt) < 0)
 688                                 error("%s", pcap_geterr(pd));
 689 #else
 690                         /*
 691                          * We don't actually support changing the
 692                          * data link type, so we only let them
 693                          * set it to what it already is.
 694                          */
 695                         if (dlt != pcap_datalink(pd)) {
 696                                 error("%s is not one of the DLTs supported by this device\n",
 697                                     dlt_name);
 698                         }
 699 #endif
 700                         (void)fprintf(stderr, "%s: data link type %s\n",
 701                                       program_name, dlt_name);
 702                         (void)fflush(stderr);
 703                 }
 704                 i = pcap_snapshot(pd);
 705                 if (snaplen < i) {
 706                         warning("snaplen raised from %d to %d", snaplen, i);
 707                         snaplen = i;
 708                 }
 709                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 710                         localnet = 0;
 711                         netmask = 0;
 712                         warning("%s", ebuf);
 713                 }
 714                 /*
 715                  * Let user own process after socket has been opened.
 716                  */
 717 #ifndef WIN32
 718                 setuid(getuid());
 719 #endif /* WIN32 */
 720         }
 721         if (infile)
 722                 cmdbuf = read_infile(infile);
 723         else
 724                 cmdbuf = copy_argv(&argv[optind]);
 725
 726         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 727                 error("%s", pcap_geterr(pd));
 728         if (dflag) {
 729                 bpf_dump(&fcode, dflag);
 730                 pcap_close(pd);
 731                 exit(0);
 732         }
 733         init_addrtoname(localnet, netmask);
 734
 735 #ifndef WIN32
 736         (void)setsignal(SIGPIPE, cleanup);
 737 #endif /* WIN32 */
 738         (void)setsignal(SIGTERM, cleanup);
 739         (void)setsignal(SIGINT, cleanup);
 740         /* Cooperate with nohup(1) */
 741 #ifndef WIN32
 742         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 743                 (void)setsignal(SIGHUP, oldhandler);
 744 #endif /* WIN32 */
 745
 746         if (pcap_setfilter(pd, &fcode) < 0)
 747                 error("%s", pcap_geterr(pd));
 748         if (WFileName) {
 749                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 750                 if (p == NULL)
 751                         error("%s", pcap_geterr(pd));
 752                 if (Cflag != 0) {
 753                         callback = dump_packet_and_trunc;
 754                         dumpinfo.WFileName = WFileName;
 755                         dumpinfo.pd = pd;
 756                         dumpinfo.p = p;
 757                         pcap_userdata = (u_char *)&dumpinfo;
 758                 } else {
 759                         callback = dump_packet;
 760                         pcap_userdata = (u_char *)p;
 761                 }
 762         } else {
 763                 type = pcap_datalink(pd);
 764                 printinfo.printer = lookup_printer(type);
 765                 if (printinfo.printer == NULL) {
 766                         dlt_name = pcap_datalink_val_to_name(type);
 767                         if (dlt_name != NULL)
 768                                 error("unsupported data link type %s", dlt_name);
 769                         else
 770                                 error("unsupported data link type %d", type);
 771                 }
 772                 callback = print_packet;
 773                 pcap_userdata = (u_char *)&printinfo;
 774         }
 775 #ifdef SIGINFO
 776         (void)setsignal(SIGINFO, requestinfo);
 777 #endif
 778 #ifndef WIN32
 779         if (RFileName == NULL) {
 780                 int dlt;
 781                 const char *dlt_name;
 782
 783                 if (!vflag && !WFileName) {
 784                         (void)fprintf(stderr,
 785                             "%s: verbose output suppressed, use -v or -vv for full protocol decode\n",
 786                             program_name);
 787                 } else
 788                         (void)fprintf(stderr, "%s: ", program_name);
 789                 dlt = pcap_datalink(pd);
 790                 dlt_name = pcap_datalink_val_to_name(dlt);
 791                 if (dlt_name == NULL) {
 792                         (void)fprintf(stderr, "listening on %s, link-type %u, capture size %u bytes\n",
 793                             device, dlt, snaplen);
 794                 } else {
 795                         (void)fprintf(stderr, "listening on %s, link-type %s (%s), capture size %u bytes\n",
 796                             device, dlt_name,
 797                             pcap_datalink_val_to_description(dlt), snaplen);
 798                 }
 799                 (void)fflush(stderr);
 800         }
 801 #endif /* WIN32 */
 802         status = pcap_loop(pd, cnt, callback, pcap_userdata);
 803         if (WFileName == NULL) {
 804                 /*
 805                  * We're printing packets.  Flush the printed output,
 806                  * so it doesn't get intermingled with error output.
 807                  */
 808                 if (status == -2) {
 809                         /*
 810                          * We got interrupted, so perhaps we didn't
 811                          * manage to finish a line we were printing.
 812                          * Print an extra newline, just in case.
 813                          */
 814                         putchar('\n');
 815                 }
 816                 (void)fflush(stdout);
 817         }
 818         if (status == -1) {
 819                 /*
 820                  * Error.  Report it.
 821                  */
 822                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 823                     program_name, pcap_geterr(pd));
 824         }
 825         if (RFileName == NULL) {
 826                 /*
 827                  * We're doing a live capture.  Report the capture
 828                  * statistics.
 829                  */
 830                 info(1);
 831         }
 832         pcap_close(pd);
 833         exit(status == -1 ? 1 : 0);
 834 }
 835
 836 /* make a clean exit on interrupts */
 837 static RETSIGTYPE
 838 cleanup(int signo _U_)
 839 {
 840 #ifdef HAVE_PCAP_BREAKLOOP
 841         /*
 842          * We have "pcap_breakloop()"; use it, so that we do as little
 843          * as possible in the signal handler (it's probably not safe
 844          * to do anything with standard I/O streams in a signal handler -
 845          * the ANSI C standard doesn't say it is).
 846          */
 847         pcap_breakloop(pd);
 848 #else
 849         /*
 850          * We don't have "pcap_breakloop()"; this isn't safe, but
 851          * it's the best we can do.  Print the summary if we're
 852          * not reading from a savefile - i.e., if we're doing a
 853          * live capture - and exit.
 854          */
 855         if (pd != NULL && pcap_file(pd) == NULL) {
 856                 /*
 857                  * We got interrupted, so perhaps we didn't
 858                  * manage to finish a line we were printing.
 859                  * Print an extra newline, just in case.
 860                  */
 861                 putchar('\n');
 862                 (void)fflush(stdout);
 863                 info(1);
 864         }
 865         exit(0);
 866 #endif
 867 }
 868
 869 static void
 870 info(register int verbose)
 871 {
 872         struct pcap_stat stat;
 873
 874         if (pcap_stats(pd, &stat) < 0) {
 875                 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
 876                 return;
 877         }
 878
 879         if (!verbose)
 880                 fprintf(stderr, "%s: ", program_name);
 881
 882         (void)fprintf(stderr, "%u packets captured", packets_captured);
 883         if (!verbose)
 884                 fputs(", ", stderr);
 885         else
 886                 putc('\n', stderr);
 887         (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
 888         if (!verbose)
 889                 fputs(", ", stderr);
 890         else
 891                 putc('\n', stderr);
 892         (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
 893         infoprint = 0;
 894 }
 895
 896 static void
 897 reverse(char *s)
 898 {
 899         int i, j, c;
 900
 901         for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
 902                 c = s[i];
 903                 s[i] = s[j];
 904                 s[j] = c;
 905         }
 906 }
 907
 908
 909 static void
 910 swebitoa(unsigned int n, char *s)
 911 {
 912         unsigned int i;
 913
 914         i = 0;
 915         do {
 916                 s[i++] = n % 10 + '0';
 917         } while ((n /= 10) > 0);
 918
 919         s[i] = '\0';
 920         reverse(s);
 921 }
 922
 923 static void
 924 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 925 {
 926         struct dump_info *dump_info;
 927         static uint cnt = 2;
 928         char *name;
 929
 930         ++packets_captured;
 931
 932         ++infodelay;
 933
 934         dump_info = (struct dump_info *)user;
 935
 936         /*
 937          * XXX - this won't prevent capture files from getting
 938          * larger than Cflag - the last packet written to the
 939          * file could put it over Cflag.
 940          */
 941         if (ftell((FILE *)dump_info->p) > Cflag) {
 942                 name = (char *) malloc(strlen(dump_info->WFileName) + 4);
 943                 if (name == NULL)
 944                         error("dump_packet_and_trunc: malloc");
 945                 strcpy(name, dump_info->WFileName);
 946                 swebitoa(cnt, name + strlen(dump_info->WFileName));
 947                 cnt++;
 948                 pcap_dump_close(dump_info->p);
 949                 dump_info->p = pcap_dump_open(dump_info->pd, name);
 950                 free(name);
 951                 if (dump_info->p == NULL)
 952                         error("%s", pcap_geterr(pd));
 953         }
 954
 955         pcap_dump((u_char *)dump_info->p, h, sp);
 956 #ifdef HAVE_PCAP_DUMP_FLUSH
 957         if (Uflag)
 958                 pcap_dump_flush(dump_info->p);
 959 #endif
 960
 961         --infodelay;
 962         if (infoprint)
 963                 info(0);
 964 }
 965
 966 static void
 967 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 968 {
 969         ++packets_captured;
 970
 971         ++infodelay;
 972
 973         pcap_dump(user, h, sp);
 974 #ifdef HAVE_PCAP_DUMP_FLUSH
 975         if (Uflag)
 976                 pcap_dump_flush((pcap_dumper_t *)user);
 977 #endif
 978
 979         --infodelay;
 980         if (infoprint)
 981                 info(0);
 982 }
 983
 984 static void
 985 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 986 {
 987         struct print_info *print_info;
 988         u_int hdrlen;
 989
 990         ++packets_captured;
 991
 992         ++infodelay;
 993         ts_print(&h->ts);
 994
 995         print_info = (struct print_info *)user;
 996
 997         /*
 998          * Some printers want to check that they're not walking off the
 999          * end of the packet.
1000          * Rather than pass it all the way down, we set this global.
1001          */
1002         snapend = sp + h->caplen;
1003
1004         hdrlen = (*print_info->printer)(h, sp);
1005         if (xflag) {
1006                 /*
1007                  * Print the raw packet data.
1008                  */
1009                 if (xflag > 1) {
1010                         /*
1011                          * Include the link-layer header.
1012                          */
1013                         default_print_unaligned(sp, h->caplen);
1014                 } else {
1015                         /*
1016                          * Don't include the link-layer header - and if
1017                          * we have nothing past the link-layer header,
1018                          * print nothing.
1019                          */
1020                         if (h->caplen > hdrlen)
1021                                 default_print_unaligned(sp + hdrlen,
1022                                     h->caplen - hdrlen);
1023                 }
1024         }
1025
1026         putchar('\n');
1027
1028         --infodelay;
1029         if (infoprint)
1030                 info(0);
1031 }
1032
1033 /* Like default_print() but data need not be aligned */
1034 void
1035 default_print_unaligned(register const u_char *cp, register u_int length)
1036 {
1037         register u_int i, s;
1038         register int nshorts;
1039
1040         if (Xflag) {
1041                 ascii_print(cp, length);
1042                 return;
1043         }
1044         nshorts = (u_int) length / sizeof(u_short);
1045         i = 0;
1046         while (--nshorts >= 0) {
1047                 if ((i++ % 8) == 0)
1048                         (void)printf("\n\t\t\t");
1049                 s = *cp++;
1050                 (void)printf(" %02x%02x", s, *cp++);
1051         }
1052         if (length & 1) {
1053                 if ((i % 8) == 0)
1054                         (void)printf("\n\t\t\t");
1055                 (void)printf(" %02x", *cp);
1056         }
1057 }
1058
1059 #ifdef WIN32
1060         /*
1061          * XXX - there should really be libpcap calls to get the version
1062          * number as a string (the string would be generated from #defines
1063          * at run time, so that it's not generated from string constants
1064          * in the library, as, on many UNIX systems, those constants would
1065          * be statically linked into the application executable image, and
1066          * would thus reflect the version of libpcap on the system on
1067          * which the application was *linked*, not the system on which it's
1068          * *running*.
1069          *
1070          * That routine should be documented, unlike the "version[]"
1071          * string, so that UNIX vendors providing their own libpcaps
1072          * don't omit it (as a couple of vendors have...).
1073          *
1074          * Packet.dll should perhaps also export a routine to return the
1075          * version number of the Packet.dll code, to supply the
1076          * "Wpcap_version" information on Windows.
1077          */
1078         char WDversion[]="current-cvs.tcpdump.org";
1079         char version[]="current-cvs.tcpdump.org";
1080         char pcap_version[]="current-cvs.tcpdump.org";
1081         char Wpcap_version[]="3.0 alpha";
1082 #endif
1083
1084 /*
1085  * By default, print the specified data out in hex.
1086  */
1087 void
1088 default_print(register const u_char *bp, register u_int length)
1089 {
1090         default_print_unaligned(bp, length);
1091 }
1092
1093 #ifdef SIGINFO
1094 RETSIGTYPE requestinfo(int signo _U_)
1095 {
1096         if (infodelay)
1097                 ++infoprint;
1098         else
1099                 info(0);
1100 }
1101 #endif
1102
1103 static void
1104 usage(void)
1105 {
1106         extern char version[];
1107 #ifndef HAVE_PCAP_LIB_VERSION
1108 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
1109         extern char pcap_version[];
1110 #else /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1111         static char pcap_version[] = "unknown";
1112 #endif /* defined(WIN32) || defined(HAVE_PCAP_VERSION) */
1113 #endif /* HAVE_PCAP_LIB_VERSION */
1114
1115 #ifdef HAVE_PCAP_LIB_VERSION
1116         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1117         (void)fprintf(stderr, "%s\n", pcap_lib_version());
1118 #else /* HAVE_PCAP_LIB_VERSION */
1119 #ifdef WIN32
1120         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1121         (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1122 #else /* WIN32 */
1123         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1124         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1125 #endif /* WIN32 */
1126 #endif /* HAVE_PCAP_LIB_VERSION */
1127         (void)fprintf(stderr,
1128 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxX]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1129         (void)fprintf(stderr,
1130 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
1131         (void)fprintf(stderr,
1132 "\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
1133         (void)fprintf(stderr,
1134 "\t\t[ expression ]\n");
1135         exit(1);
1136 }