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 1.194 2002-12-22 00:15:28 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 aflag;                      /* translate network and broadcast addresses */
  73 int dflag;                      /* print filter code */
  74 int eflag;                      /* print ethernet header */
  75 int fflag;                      /* don't translate "foreign" IP address */
  76 int Lflag;                      /* list available data link types and exit */
  77 int nflag;                      /* leave addresses as numbers */
  78 int Nflag;                      /* remove domains from printed host names */
  79 int Oflag = 1;                  /* run filter code optimizer */
  80 int pflag;                      /* don't go promiscuous */
  81 int qflag;                      /* quick (shorter) output */
  82 int Rflag = 1;                  /* print sequence # field in AH/ESP*/
  83 int sflag = 0;                  /* use the libsmi to translate OIDs */
  84 int Sflag;                      /* print raw TCP sequence numbers */
  85 int tflag = 1;                  /* print packet arrival time */
  86 int Uflag = 0;                  /* "unbuffered" output of dump files */
  87 int uflag = 0;                  /* Print undecoded NFS handles */
  88 int vflag;                      /* verbose */
  89 int xflag;                      /* print packet in hex */
  90 int Xflag;                      /* print packet in ascii as well as hex */
  91 off_t Cflag = 0;                /* rotate dump files after this many bytes */
  92 int Aflag = 0;                  /* print packet only in ascii observing LF, CR, TAB, SPACE */
  93 int dlt = -1;           /* if != -1, ask libpcap for the DLT it names */
  94
  95 const char *dlt_name = NULL;
  96
  97 char *espsecret = NULL;         /* ESP secret key */
  98
  99 int packettype;
 100
 101 static int infodelay;
 102 static int infoprint;
 103
 104 char *program_name;
 105
 106 int32_t thiszone;               /* seconds offset from gmt to local time */
 107
 108 /* Forwards */
 109 static RETSIGTYPE cleanup(int);
 110 static void usage(void) __attribute__((noreturn));
 111 static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
 112
 113 static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 114 static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
 115 static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
 116
 117 #ifdef SIGINFO
 118 RETSIGTYPE requestinfo(int);
 119 #endif
 120
 121 static void info(int);
 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         { ether_if_print,       DLT_EN10MB },
 136         { token_if_print,       DLT_IEEE802 },
 137 #ifdef DLT_LANE8023
 138         { lane_if_print,        DLT_LANE8023 },
 139 #endif
 140 #ifdef DLT_CIP
 141         { cip_if_print,         DLT_CIP },
 142 #endif
 143 #ifdef DLT_ATM_CLIP
 144         { cip_if_print,         DLT_ATM_CLIP },
 145 #endif
 146         { sl_if_print,          DLT_SLIP },
 147         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 148         { ppp_if_print,         DLT_PPP },
 149         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 150         { fddi_if_print,        DLT_FDDI },
 151         { null_if_print,        DLT_NULL },
 152 #ifdef DLT_LOOP
 153         { null_if_print,        DLT_LOOP },
 154 #endif
 155         { raw_if_print,         DLT_RAW },
 156         { atm_if_print,         DLT_ATM_RFC1483 },
 157 #ifdef DLT_C_HDLC
 158         { chdlc_if_print,       DLT_C_HDLC },
 159 #endif
 160 #ifdef DLT_HDLC
 161         { chdlc_if_print,       DLT_HDLC },
 162 #endif
 163 #ifdef DLT_PPP_SERIAL
 164         { ppp_hdlc_if_print,    DLT_PPP_SERIAL },
 165 #endif
 166 #ifdef DLT_PPP_ETHER
 167         { pppoe_if_print,       DLT_PPP_ETHER },
 168 #endif
 169 #ifdef DLT_LINUX_SLL
 170         { sll_if_print,         DLT_LINUX_SLL },
 171 #endif
 172 #ifdef DLT_IEEE802_11
 173         { ieee802_11_if_print,  DLT_IEEE802_11},
 174 #endif
 175 #ifdef DLT_LTALK
 176         { ltalk_if_print,       DLT_LTALK },
 177 #endif
 178 #ifdef DLT_PFLOG
 179         { pflog_if_print,       DLT_PFLOG },
 180 #endif
 181 #ifdef DLT_FR
 182         { fr_if_print,          DLT_FR },
 183 #endif
 184 #ifdef DLT_FRELAY
 185         { fr_if_print,          DLT_FRELAY },
 186 #endif
 187 #ifdef DLT_SUNATM
 188         { sunatm_if_print,      DLT_SUNATM },
 189 #endif
 190 #ifdef DLT_IP_OVER_FC
 191         { ipfc_if_print,        DLT_IP_OVER_FC },
 192 #endif
 193 #ifdef DLT_PRISM_HEADER
 194         { prism_if_print,       DLT_PRISM_HEADER },
 195 #endif
 196 #ifdef DLT_IEEE802_11_RADIO
 197         { ieee802_11_radio_if_print,    DLT_IEEE802_11_RADIO },
 198 #endif
 199         { NULL,                 0 },
 200 };
 201
 202 static if_printer
 203 lookup_printer(int type)
 204 {
 205         struct printer *p;
 206
 207         for (p = printers; p->f; ++p)
 208                 if (type == p->type)
 209                         return p->f;
 210
 211         return NULL;
 212         /* NOTREACHED */
 213 }
 214
 215 static pcap_t *pd;
 216
 217 extern int optind;
 218 extern int opterr;
 219 extern char *optarg;
 220
 221 struct print_info {
 222         if_printer printer;
 223 };
 224
 225 struct dump_info {
 226         char    *WFileName;
 227         pcap_t  *pd;
 228         pcap_dumper_t *p;
 229 };
 230
 231 static void
 232 show_dlts_and_exit(pcap_t *pd)
 233 {
 234         int n_dlts;
 235         int *dlts = 0;
 236         const char *dlt_name;
 237
 238         n_dlts = pcap_list_datalinks(pd, &dlts);
 239         if (n_dlts < 0)
 240                 error("%s", pcap_geterr(pd));
 241         else if (n_dlts == 0 || !dlts)
 242                 error("No data link types.");
 243
 244         (void) fprintf(stderr, "Data link types (use option -y to set):\n");
 245
 246         while (--n_dlts >= 0) {
 247                 dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
 248                 if (dlt_name != NULL) {
 249                         (void) fprintf(stderr, "  %s", dlt_name);
 250
 251                         /*
 252                          * OK, does tcpdump handle that type?
 253                          */
 254                         if (lookup_printer(dlts[n_dlts]) == NULL)
 255                                 (void) fprintf(stderr, " (not supported)");
 256                         putchar('\n');
 257                 } else {
 258                         (void) fprintf(stderr, "  DLT %d (not supported)\n",
 259                             dlts[n_dlts]);
 260                 }
 261         }
 262         free(dlts);
 263         exit(0);
 264 }
 265
 266 /*
 267  * Set up flags that might or might not be supported depending on the
 268  * version of libpcap we're using.
 269  *
 270  * Win32 builds are assumed to be done with the latest version of WinPcap.
 271  */
 272 #ifdef WIN32
 273 #define B_FLAG          "B:"
 274 #define B_FLAG_USAGE    " [ -B size ]"
 275 #define D_FLAG          "D"
 276 #define U_FLAG          "U"
 277 #else /* WIN32 */
 278
 279 #define B_FLAG
 280 #define B_FLAG_USAGE
 281
 282 #ifdef HAVE_PCAP_FINDALLDEVS
 283 #define D_FLAG  "D"
 284 #else
 285 #define D_FLAG
 286 #endif
 287
 288 #ifdef HAVE_PCAP_DUMP_FLUSH
 289 #define U_FLAG  "U"
 290 #else
 291 #define U_FLAG
 292 #endif
 293
 294 #endif /* WIN32 */
 295
 296 int
 297 main(int argc, char **argv)
 298 {
 299         register int cnt, op, i;
 300         bpf_u_int32 localnet, netmask;
 301         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
 302         pcap_handler callback;
 303         int type;
 304         struct bpf_program fcode;
 305 #ifndef WIN32
 306         RETSIGTYPE (*oldhandler)(int);
 307 #endif
 308         struct print_info printinfo;
 309         struct dump_info dumpinfo;
 310         u_char *pcap_userdata;
 311         char ebuf[PCAP_ERRBUF_SIZE];
 312 #ifdef HAVE_PCAP_FINDALLDEVS
 313         pcap_if_t *devpointer;
 314         int devnum;
 315 #endif
 316 #ifdef WIN32
 317         DWORD dwVersion;
 318         DWORD dwWindowsMajorVersion;
 319         u_int UserBufferSize=1000000;
 320 #endif
 321
 322 #ifdef WIN32
 323         dwVersion=GetVersion();         /* get the OS version */
 324         dwWindowsMajorVersion =  (DWORD)(LOBYTE(LOWORD(dwVersion)));
 325         if(wsockinit()!=0) return 1;
 326 #endif /* WIN32 */
 327
 328         cnt = -1;
 329         device = NULL;
 330         infile = NULL;
 331         RFileName = NULL;
 332         WFileName = NULL;
 333         if ((cp = strrchr(argv[0], '/')) != NULL)
 334                 program_name = cp + 1;
 335         else
 336                 program_name = argv[0];
 337
 338         if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
 339                 error("%s", ebuf);
 340
 341 #ifdef LIBSMI
 342         smiInit("tcpdump");
 343 #endif
 344
 345         opterr = 0;
 346         while (
 347             (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)
 348                 switch (op) {
 349
 350                 case 'a':
 351                         ++aflag;
 352                         break;
 353
 354                 case 'A':
 355                         ++xflag;
 356                         ++Xflag;
 357                         ++Aflag;
 358                         break;
 359
 360 #ifdef WIN32
 361                 case 'B':
 362                         UserBufferSize = atoi(optarg)*1024;
 363                         if (UserBufferSize < 0)
 364                                 error("invalid packet buffer size %s", optarg);
 365                         break;
 366 #endif /* WIN32 */
 367
 368                 case 'c':
 369                         cnt = atoi(optarg);
 370                         if (cnt <= 0)
 371                                 error("invalid packet count %s", optarg);
 372                         break;
 373
 374                 case 'C':
 375                         Cflag = atoi(optarg) * 1000000;
 376                         if (Cflag < 0)
 377                                 error("invalid file size %s", optarg);
 378                         break;
 379
 380                 case 'd':
 381                         ++dflag;
 382                         break;
 383
 384 #ifdef HAVE_PCAP_FINDALLDEVS
 385                 case 'D':
 386                         if (pcap_findalldevs(&devpointer, ebuf) < 0)
 387                                 error("%s", ebuf);
 388                         else {
 389                                 for (i = 0; devpointer != 0; i++) {
 390                                         printf("%d.%s", i+1, devpointer->name);
 391                                         if (devpointer->description != NULL)
 392                                                 printf(" (%s)", devpointer->description);
 393                                         printf("\n");
 394                                         devpointer = devpointer->next;
 395                                 }
 396                         }
 397                         return 0;
 398 #endif /* HAVE_PCAP_FINDALLDEVS */
 399
 400                 case 'L':
 401                         Lflag++;
 402                         break;
 403
 404                 case 'e':
 405                         ++eflag;
 406                         break;
 407
 408                 case 'E':
 409 #ifndef HAVE_LIBCRYPTO
 410                         warning("crypto code not compiled in");
 411 #endif
 412                         espsecret = optarg;
 413                         break;
 414
 415                 case 'f':
 416                         ++fflag;
 417                         break;
 418
 419                 case 'F':
 420                         infile = optarg;
 421                         break;
 422
 423                 case 'i':
 424                         if (optarg[0] == '0' && optarg[1] == 0)
 425                                 error("Invalid adapter index");
 426
 427 #ifdef HAVE_PCAP_FINDALLDEVS
 428                         /*
 429                          * If the argument is a number, treat it as
 430                          * an index into the list of adapters, as
 431                          * printed by "tcpdump -D".
 432                          *
 433                          * This should be OK on UNIX systems, as interfaces
 434                          * shouldn't have names that begin with digits.
 435                          * It can be useful on Windows, where more than
 436                          * one interface can have the same name.
 437                          */
 438                         if ((devnum = atoi(optarg)) != 0) {
 439                                 if (devnum < 0)
 440                                         error("Invalid adapter index");
 441
 442                                 if (pcap_findalldevs(&devpointer, ebuf) < 0)
 443                                         error("%s", ebuf);
 444                                 else {
 445                                         for (i = 0; i < devnum-1; i++){
 446                                                 devpointer = devpointer->next;
 447                                                 if (devpointer == NULL)
 448                                                         error("Invalid adapter index");
 449                                         }
 450                                 }
 451                                 device = devpointer->name;
 452                                 break;
 453                         }
 454 #endif /* HAVE_PCAP_FINDALLDEVS */
 455                         device = optarg;
 456                         break;
 457
 458                 case 'l':
 459 #ifdef HAVE_SETLINEBUF
 460                         setlinebuf(stdout);
 461 #else
 462                         setvbuf(stdout, NULL, _IOLBF, 0);
 463 #endif
 464                         break;
 465
 466                 case 'n':
 467                         ++nflag;
 468                         break;
 469
 470                 case 'N':
 471                         ++Nflag;
 472                         break;
 473
 474                 case 'm':
 475 #ifdef LIBSMI
 476                         if (smiLoadModule(optarg) == 0) {
 477                                 error("could not load MIB module %s", optarg);
 478                         }
 479                         sflag = 1;
 480 #else
 481                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 482                                       program_name, optarg);
 483                         (void)fprintf(stderr, "(no libsmi support)\n");
 484 #endif
 485
 486                 case 'O':
 487                         Oflag = 0;
 488                         break;
 489
 490                 case 'p':
 491                         ++pflag;
 492                         break;
 493
 494                 case 'q':
 495                         ++qflag;
 496                         break;
 497
 498                 case 'r':
 499                         RFileName = optarg;
 500                         break;
 501
 502                 case 'R':
 503                         Rflag = 0;
 504                         break;
 505
 506                 case 's': {
 507                         char *end;
 508
 509                         snaplen = strtol(optarg, &end, 0);
 510                         if (optarg == end || *end != '\0'
 511                             || snaplen < 0 || snaplen > 65535)
 512                                 error("invalid snaplen %s", optarg);
 513                         else if (snaplen == 0)
 514                                 snaplen = 65535;
 515                         break;
 516                 }
 517
 518                 case 'S':
 519                         ++Sflag;
 520                         break;
 521
 522                 case 't':
 523                         --tflag;
 524                         break;
 525
 526                 case 'T':
 527                         if (strcasecmp(optarg, "vat") == 0)
 528                                 packettype = PT_VAT;
 529                         else if (strcasecmp(optarg, "wb") == 0)
 530                                 packettype = PT_WB;
 531                         else if (strcasecmp(optarg, "rpc") == 0)
 532                                 packettype = PT_RPC;
 533                         else if (strcasecmp(optarg, "rtp") == 0)
 534                                 packettype = PT_RTP;
 535                         else if (strcasecmp(optarg, "rtcp") == 0)
 536                                 packettype = PT_RTCP;
 537                         else if (strcasecmp(optarg, "snmp") == 0)
 538                                 packettype = PT_SNMP;
 539                         else if (strcasecmp(optarg, "cnfp") == 0)
 540                                 packettype = PT_CNFP;
 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 (aflag && nflag)
 599                 error("-a and -n options are incompatible");
 600
 601         if (tflag > 0)
 602                 thiszone = gmt2local(0);
 603
 604         if (RFileName != NULL) {
 605                 /*
 606                  * We don't need network access, so set it back to the user id.
 607                  * Also, this prevents the user from reading anyone's
 608                  * trace file.
 609                  */
 610 #ifndef WIN32
 611                 setuid(getuid());
 612 #endif /* WIN32 */
 613
 614                 pd = pcap_open_offline(RFileName, ebuf);
 615                 if (pd == NULL)
 616                         error("%s", ebuf);
 617                 localnet = 0;
 618                 netmask = 0;
 619                 if (fflag != 0)
 620                         error("-f and -r options are incompatible");
 621         } else {
 622                 if (device == NULL) {
 623                         device = pcap_lookupdev(ebuf);
 624                         if (device == NULL)
 625                                 error("%s", ebuf);
 626                 }
 627 #ifdef WIN32
 628                 PrintCapBegins(program_name,device);
 629 #endif /* WIN32 */
 630                 *ebuf = '\0';
 631                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 632                 if (pd == NULL)
 633                         error("%s", ebuf);
 634                 else if (*ebuf)
 635                         warning("%s", ebuf);
 636 #ifdef WIN32
 637                 if(UserBufferSize != 1000000)
 638                         if(pcap_setbuff(pd, UserBufferSize)==-1){
 639                                 error("%s", pcap_geterr(pd));
 640                         }
 641 #endif /* WIN32 */
 642                 if (Lflag)
 643                         show_dlts_and_exit(pd);
 644                 if (dlt >= 0) {
 645 #ifdef HAVE_PCAP_SET_DATALINK
 646                         if (pcap_set_datalink(pd, dlt) < 0)
 647                                 error("%s", pcap_geterr(pd));
 648 #else
 649                         /*
 650                          * We don't actually support changing the
 651                          * data link type, so we only let them
 652                          * set it to what it already is.
 653                          */
 654                         if (dlt != pcap_datalink(pd)) {
 655                                 error("%s is not one of the DLTs supported by this device\n",
 656                                     dlt_name);
 657                         }
 658 #endif
 659                         (void)fprintf(stderr, "%s: data link type %s\n",
 660                                       program_name, dlt_name);
 661                         (void)fflush(stderr);
 662                 }
 663                 i = pcap_snapshot(pd);
 664                 if (snaplen < i) {
 665                         warning("snaplen raised from %d to %d", snaplen, i);
 666                         snaplen = i;
 667                 }
 668                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 669                         localnet = 0;
 670                         netmask = 0;
 671                         warning("%s", ebuf);
 672                 }
 673                 /*
 674                  * Let user own process after socket has been opened.
 675                  */
 676 #ifndef WIN32
 677                 setuid(getuid());
 678 #endif /* WIN32 */
 679         }
 680         if (infile)
 681                 cmdbuf = read_infile(infile);
 682         else
 683                 cmdbuf = copy_argv(&argv[optind]);
 684
 685         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 686                 error("%s", pcap_geterr(pd));
 687         if (dflag) {
 688                 bpf_dump(&fcode, dflag);
 689                 pcap_close(pd);
 690                 exit(0);
 691         }
 692         init_addrtoname(localnet, netmask);
 693
 694         (void)setsignal(SIGTERM, cleanup);
 695         (void)setsignal(SIGINT, cleanup);
 696         /* Cooperate with nohup(1) */
 697 #ifndef WIN32
 698         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 699                 (void)setsignal(SIGHUP, oldhandler);
 700 #endif /* WIN32 */
 701
 702         if (pcap_setfilter(pd, &fcode) < 0)
 703                 error("%s", pcap_geterr(pd));
 704         if (WFileName) {
 705                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 706                 if (p == NULL)
 707                         error("%s", pcap_geterr(pd));
 708                 if (Cflag != 0) {
 709                         callback = dump_packet_and_trunc;
 710                         dumpinfo.WFileName = WFileName;
 711                         dumpinfo.pd = pd;
 712                         dumpinfo.p = p;
 713                         pcap_userdata = (u_char *)&dumpinfo;
 714                 } else {
 715                         callback = dump_packet;
 716                         pcap_userdata = (u_char *)p;
 717                 }
 718         } else {
 719                 type = pcap_datalink(pd);
 720                 printinfo.printer = lookup_printer(type);
 721                 if (printinfo.printer == NULL) {
 722                         dlt_name = pcap_datalink_val_to_name(type);
 723                         if (dlt_name != NULL)
 724                                 error("unsupported data link type %s", dlt_name);
 725                         else
 726                                 error("unsupported data link type %d", type);
 727                 }
 728                 callback = print_packet;
 729                 pcap_userdata = (u_char *)&printinfo;
 730         }
 731 #ifdef SIGINFO
 732         (void)setsignal(SIGINFO, requestinfo);
 733 #endif
 734 #ifndef WIN32
 735         if (RFileName == NULL) {
 736                 (void)fprintf(stderr, "%s: listening on %s\n",
 737                     program_name, device);
 738                 (void)fflush(stderr);
 739         }
 740 #endif /* WIN32 */
 741         if (pcap_loop(pd, cnt, callback, pcap_userdata) < 0) {
 742                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 743                     program_name, pcap_geterr(pd));
 744                 cleanup(0);
 745                 pcap_close(pd);
 746                 exit(1);
 747         }
 748         if (RFileName == NULL)
 749                 info(1);
 750         pcap_close(pd);
 751         exit(0);
 752 }
 753
 754 /* make a clean exit on interrupts */
 755 static RETSIGTYPE
 756 cleanup(int signo)
 757 {
 758
 759         /* Can't print the summary if reading from a savefile */
 760         if (pd != NULL && pcap_file(pd) == NULL) {
 761                 (void)fflush(stdout);
 762                 putc('\n', stderr);
 763                 info(1);
 764         }
 765         if (signo)
 766                 exit(0);
 767 }
 768
 769 static void
 770 info(register int verbose)
 771 {
 772         struct pcap_stat stat;
 773
 774         if (pcap_stats(pd, &stat) < 0) {
 775                 (void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
 776                 return;
 777         }
 778
 779         if (!verbose)
 780                 fprintf(stderr, "%s: ", program_name);
 781
 782         (void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
 783         if (!verbose)
 784                 fputs(", ", stderr);
 785         else
 786                 putc('\n', stderr);
 787         (void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
 788         infoprint = 0;
 789 }
 790
 791 static void
 792 reverse(char *s)
 793 {
 794         int i, j, c;
 795
 796         for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
 797                 c = s[i];
 798                 s[i] = s[j];
 799                 s[j] = c;
 800         }
 801 }
 802
 803
 804 static void
 805 swebitoa(unsigned int n, char *s)
 806 {
 807         unsigned int i;
 808
 809         i = 0;
 810         do {
 811                 s[i++] = n % 10 + '0';
 812         } while ((n /= 10) > 0);
 813
 814         s[i] = '\0';
 815         reverse(s);
 816 }
 817
 818 static void
 819 dump_packet_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 820 {
 821         struct dump_info *dump_info;
 822         static uint cnt = 2;
 823         char *name;
 824
 825         ++infodelay;
 826
 827         dump_info = (struct dump_info *)user;
 828
 829         /*
 830          * XXX - this won't prevent capture files from getting
 831          * larger than Cflag - the last packet written to the
 832          * file could put it over Cflag.
 833          */
 834         if (ftell((FILE *)dump_info->p) > Cflag) {
 835                 name = (char *) malloc(strlen(dump_info->WFileName) + 4);
 836                 if (name == NULL)
 837                         error("dump_packet_and_trunc: malloc");
 838                 strcpy(name, dump_info->WFileName);
 839                 swebitoa(cnt, name + strlen(dump_info->WFileName));
 840                 cnt++;
 841                 pcap_dump_close(dump_info->p);
 842                 dump_info->p = pcap_dump_open(dump_info->pd, name);
 843                 free(name);
 844                 if (dump_info->p == NULL)
 845                         error("%s", pcap_geterr(pd));
 846         }
 847
 848         pcap_dump((u_char *)dump_info->p, h, sp);
 849 #ifdef HAVE_PCAP_FINDALLDEVS
 850         if (Uflag)
 851                 pcap_dump_flush(dump_info->p);
 852 #endif
 853
 854         --infodelay;
 855         if (infoprint)
 856                 info(0);
 857 }
 858
 859 static void
 860 dump_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 861 {
 862         ++infodelay;
 863
 864         pcap_dump(user, h, sp);
 865 #ifdef HAVE_PCAP_FINDALLDEVS
 866         if (Uflag)
 867                 pcap_dump_flush((pcap_dumper_t *)user);
 868 #endif
 869
 870         --infodelay;
 871         if (infoprint)
 872                 info(0);
 873 }
 874
 875 static void
 876 print_packet(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
 877 {
 878         struct print_info *print_info;
 879         u_int hdrlen;
 880
 881         ++infodelay;
 882         ts_print(&h->ts);
 883
 884         print_info = (struct print_info *)user;
 885
 886         /*
 887          * Some printers want to check that they're not walking off the
 888          * end of the packet.
 889          * Rather than pass it all the way down, we set this global.
 890          */
 891         snapend = sp + h->caplen;
 892
 893         hdrlen = (*print_info->printer)(h, sp);
 894         if (xflag) {
 895                 /*
 896                  * Print the raw packet data.
 897                  */
 898                 if (xflag > 1) {
 899                         /*
 900                          * Include the link-layer header.
 901                          */
 902                         default_print_unaligned(sp, h->caplen);
 903                 } else {
 904                         /*
 905                          * Don't include the link-layer header - and if
 906                          * we have nothing past the link-layer header,
 907                          * print nothing.
 908                          */
 909                         if (h->caplen > hdrlen)
 910                                 default_print_unaligned(sp + hdrlen,
 911                                     h->caplen - hdrlen);
 912                 }
 913         }
 914
 915         putchar('\n');
 916
 917         --infodelay;
 918         if (infoprint)
 919                 info(0);
 920 }
 921
 922 /* Like default_print() but data need not be aligned */
 923 void
 924 default_print_unaligned(register const u_char *cp, register u_int length)
 925 {
 926         register u_int i, s;
 927         register int nshorts;
 928
 929         if (Xflag) {
 930                 ascii_print(cp, length);
 931                 return;
 932         }
 933         nshorts = (u_int) length / sizeof(u_short);
 934         i = 0;
 935         while (--nshorts >= 0) {
 936                 if ((i++ % 8) == 0)
 937                         (void)printf("\n\t\t\t");
 938                 s = *cp++;
 939                 (void)printf(" %02x%02x", s, *cp++);
 940         }
 941         if (length & 1) {
 942                 if ((i % 8) == 0)
 943                         (void)printf("\n\t\t\t");
 944                 (void)printf(" %02x", *cp);
 945         }
 946 }
 947
 948 #ifdef WIN32
 949         /*
 950          * XXX - there should really be libpcap calls to get the version
 951          * number as a string (the string would be generated from #defines
 952          * at run time, so that it's not generated from string constants
 953          * in the library, as, on many UNIX systems, those constants would
 954          * be statically linked into the application executable image, and
 955          * would thus reflect the version of libpcap on the system on
 956          * which the application was *linked*, not the system on which it's
 957          * *running*.
 958          *
 959          * That routine should be documented, unlike the "version[]"
 960          * string, so that UNIX vendors providing their own libpcaps
 961          * don't omit it (as a couple of vendors have...).
 962          *
 963          * Packet.dll should perhaps also export a routine to return the
 964          * version number of the Packet.dll code, to supply the
 965          * "Wpcap_version" information on Windows.
 966          */
 967         char WDversion[]="current-cvs.tcpdump.org";
 968         char version[]="current-cvs.tcpdump.org";
 969         char pcap_version[]="current-cvs.tcpdump.org";
 970         char Wpcap_version[]="3.0 alpha";
 971 #endif
 972
 973 /*
 974  * By default, print the specified data out in hex.
 975  */
 976 void
 977 default_print(register const u_char *bp, register u_int length)
 978 {
 979         default_print_unaligned(bp, length);
 980 }
 981
 982 #ifdef SIGINFO
 983 RETSIGTYPE requestinfo(int signo _U_)
 984 {
 985         if (infodelay)
 986                 ++infoprint;
 987         else
 988                 info(0);
 989 }
 990 #endif
 991
 992 static void
 993 usage(void)
 994 {
 995         extern char version[];
 996 #if defined(WIN32) || defined(HAVE_PCAP_VERSION)
 997         extern char pcap_version[];
 998 #else
 999         static char pcap_version[] = "unknown";
1000 #endif
1001
1002 #ifdef WIN32
1003         (void)fprintf(stderr, "%s version %s, based on tcpdump version %s\n", program_name, WDversion, version);
1004         (void)fprintf(stderr, "WinPcap version %s, based on libpcap version %s\n",Wpcap_version, pcap_version);
1005 #else
1006         (void)fprintf(stderr, "%s version %s\n", program_name, version);
1007         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
1008 #endif /* WIN32 */
1009         (void)fprintf(stderr,
1010 "Usage: %s [-aAd" D_FLAG "eflLnNOpqRStu" U_FLAG "vxXy]" B_FLAG_USAGE " [-c count] [ -C file_size ]\n", program_name);
1011         (void)fprintf(stderr,
1012 "\t\t[ -E algo:secret ] [ -F file ] [ -i interface ] [ -r file ]\n");
1013         (void)fprintf(stderr,
1014 "\t\t[ -s snaplen ] [ -T type ] [ -w file ] [ -y datalinktype ]\n");
1015         (void)fprintf(stderr,
1016 "\t\t[ expression ]\n");
1017         exit(1);
1018 }