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

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   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
  22 #ifndef lint
  23 static const char copyright[] =
  24     "@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997\n\
  25 The Regents of the University of California.  All rights reserved.\n";
  26 static const char rcsid[] =
  27     "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.137 1999-12-22 06:27:24 itojun Exp $ (LBL)";
  28 #endif
  29
  30 /*
  31  * tcpdump - monitor tcp/ip traffic on an ethernet.
  32  *
  33  * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory.
  34  * Mercilessly hacked and occasionally improved since then via the
  35  * combined efforts of Van, Steve McCanne and Craig Leres of LBL.
  36  */
  37
  38 #ifdef HAVE_CONFIG_H
  39 #include "config.h"
  40 #endif
  41
  42 #include <sys/types.h>
  43 #include <sys/time.h>
  44
  45 #include <netinet/in.h>
  46
  47 #include <pcap.h>
  48 #include <signal.h>
  49 #include <stdio.h>
  50 #include <stdlib.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53 #include <ctype.h>
  54
  55 #include <netinet/in_systm.h>
  56 #include <netinet/ip.h>
  57
  58 #include "interface.h"
  59 #include "addrtoname.h"
  60 #include "machdep.h"
  61 #include "setsignal.h"
  62 #include "gmt2local.h"
  63
  64 int aflag;                      /* translate network and broadcast addresses */
  65 int dflag;                      /* print filter code */
  66 int eflag;                      /* print ethernet header */
  67 int fflag;                      /* don't translate "foreign" IP address */
  68 int nflag;                      /* leave addresses as numbers */
  69 int Nflag;                      /* remove domains from printed host names */
  70 int Oflag = 1;                  /* run filter code optimizer */
  71 int pflag;                      /* don't go promiscuous */
  72 int qflag;                      /* quick (shorter) output */
  73 int Rflag = 1;                  /* print sequence # field in AH/ESP*/
  74 int sflag = 0;                  /* use the libsmi to translate OIDs */
  75 int Sflag;                      /* print raw TCP sequence numbers */
  76 int tflag = 1;                  /* print packet arrival time */
  77 int vflag;                      /* verbose */
  78 int xflag;                      /* print packet in hex */
  79
  80 char *ahsecret = NULL;          /* AH secret key */
  81 char *espsecret = NULL;         /* ESP secret key */
  82
  83 int packettype;
  84
  85
  86 char *program_name;
  87
  88 int32_t thiszone;               /* seconds offset from gmt to local time */
  89
  90 /* Externs */
  91 extern void bpf_dump(struct bpf_program *, int);
  92
  93 /* Forwards */
  94 RETSIGTYPE cleanup(int);
  95 extern __dead void usage(void) __attribute__((volatile));
  96
  97 /* Length of saved portion of packet. */
  98 int snaplen = DEFAULT_SNAPLEN;
  99
 100 struct printer {
 101         pcap_handler f;
 102         int type;
 103 };
 104
 105 static struct printer printers[] = {
 106         { ether_if_print,       DLT_EN10MB },
 107         { ether_if_print,       DLT_IEEE802 },
 108 #ifdef DLT_LANE8023
 109         { lane_if_print,        DLT_LANE8023 },
 110 #endif
 111 #ifdef DLT_CIP
 112         { cip_if_print,         DLT_CIP },
 113 #endif
 114         { sl_if_print,          DLT_SLIP },
 115         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 116         { ppp_if_print,         DLT_PPP },
 117         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 118         { fddi_if_print,        DLT_FDDI },
 119         { null_if_print,        DLT_NULL },
 120         { raw_if_print,         DLT_RAW },
 121         { atm_if_print,         DLT_ATM_RFC1483 },
 122 #ifdef DLT_CHDLC
 123         { chdlc_if_print,       DLT_CHDLC },
 124 #endif
 125         { NULL,                 0 },
 126 };
 127
 128 static pcap_handler
 129 lookup_printer(int type)
 130 {
 131         struct printer *p;
 132
 133         for (p = printers; p->f; ++p)
 134                 if (type == p->type)
 135                         return p->f;
 136
 137         error("unknown data link type 0x%x", type);
 138         /* NOTREACHED */
 139 }
 140
 141 static pcap_t *pd;
 142
 143 extern int optind;
 144 extern int opterr;
 145 extern char *optarg;
 146
 147 int
 148 main(int argc, char **argv)
 149 {
 150         register int cnt, op, i;
 151         bpf_u_int32 localnet, netmask;
 152         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
 153         pcap_handler printer;
 154         struct bpf_program fcode;
 155         RETSIGTYPE (*oldhandler)(int);
 156         u_char *pcap_userdata;
 157         char ebuf[PCAP_ERRBUF_SIZE];
 158
 159         cnt = -1;
 160         device = NULL;
 161         infile = NULL;
 162         RFileName = NULL;
 163         WFileName = NULL;
 164         if ((cp = strrchr(argv[0], '/')) != NULL)
 165                 program_name = cp + 1;
 166         else
 167                 program_name = argv[0];
 168
 169         if (abort_on_misalignment(ebuf) < 0)
 170                 error("%s", ebuf);
 171
 172 #ifdef LIBSMI
 173         smiInit("tcpdump");
 174 #endif
 175
 176         opterr = 0;
 177         while (
 178             (op = getopt(argc, argv, "ac:deE:fF:i:lnNm:Opqr:Rs:StT:vw:xY")) != EOF)
 179                 switch (op) {
 180
 181                 case 'a':
 182                         ++aflag;
 183                         break;
 184
 185 #if 0
 186                 case 'A':
 187 #ifndef CRYPTO
 188                         warning("crypto code not compiled in");
 189 #endif
 190                         ahsecret = optarg;
 191                         break;
 192 #endif
 193
 194                 case 'c':
 195                         cnt = atoi(optarg);
 196                         if (cnt <= 0)
 197                                 error("invalid packet count %s", optarg);
 198                         break;
 199
 200                 case 'd':
 201                         ++dflag;
 202                         break;
 203
 204                 case 'e':
 205                         ++eflag;
 206                         break;
 207
 208                 case 'E':
 209 #ifndef CRYPTO
 210                         warning("crypto code not compiled in");
 211 #endif
 212                         espsecret = optarg;
 213                         break;
 214
 215                 case 'f':
 216                         ++fflag;
 217                         break;
 218
 219                 case 'F':
 220                         infile = optarg;
 221                         break;
 222
 223                 case 'i':
 224                         device = optarg;
 225                         break;
 226
 227                 case 'l':
 228 #ifdef HAVE_SETLINEBUF
 229                         setlinebuf(stdout);
 230 #else
 231                         setvbuf(stdout, NULL, _IOLBF, 0);
 232 #endif
 233                         break;
 234
 235                 case 'n':
 236                         ++nflag;
 237                         break;
 238
 239                 case 'N':
 240                         ++Nflag;
 241                         break;
 242
 243                 case 'm':
 244 #ifdef LIBSMI
 245                         if (smiLoadModule(optarg) == 0) {
 246                                 error("could not load MIB module %s", optarg);
 247                         }
 248                         sflag = 1;
 249 #else
 250                         (void)fprintf(stderr, "%s: ignoring option `-m %s' ",
 251                                       program_name, optarg);
 252                         (void)fprintf(stderr, "(no libsmi support)\n");
 253 #endif
 254
 255                 case 'O':
 256                         Oflag = 0;
 257                         break;
 258
 259                 case 'p':
 260                         ++pflag;
 261                         break;
 262
 263                 case 'q':
 264                         ++qflag;
 265                         break;
 266
 267                 case 'r':
 268                         RFileName = optarg;
 269                         break;
 270
 271                 case 'R':
 272                         Rflag = 0;
 273                         break;
 274
 275                 case 's':
 276                         snaplen = atoi(optarg);
 277                         if (snaplen <= 0)
 278                                 error("invalid snaplen %s", optarg);
 279                         break;
 280
 281                 case 'S':
 282                         ++Sflag;
 283                         break;
 284
 285                 case 't':
 286                         --tflag;
 287                         break;
 288
 289                 case 'T':
 290                         if (strcasecmp(optarg, "vat") == 0)
 291                                 packettype = PT_VAT;
 292                         else if (strcasecmp(optarg, "wb") == 0)
 293                                 packettype = PT_WB;
 294                         else if (strcasecmp(optarg, "rpc") == 0)
 295                                 packettype = PT_RPC;
 296                         else if (strcasecmp(optarg, "rtp") == 0)
 297                                 packettype = PT_RTP;
 298                         else if (strcasecmp(optarg, "rtcp") == 0)
 299                                 packettype = PT_RTCP;
 300                         else if (strcasecmp(optarg, "snmp") == 0)
 301                                 packettype = PT_SNMP;
 302                         else
 303                                 error("unknown packet type `%s'", optarg);
 304                         break;
 305
 306                 case 'v':
 307                         ++vflag;
 308                         break;
 309
 310                 case 'w':
 311                         WFileName = optarg;
 312                         break;
 313 #ifdef YYDEBUG
 314                 case 'Y':
 315                         {
 316                         /* Undocumented flag */
 317                         extern int yydebug;
 318                         yydebug = 1;
 319                         }
 320                         break;
 321 #endif
 322                 case 'x':
 323                         ++xflag;
 324                         break;
 325
 326                 default:
 327                         usage();
 328                         /* NOTREACHED */
 329                 }
 330
 331         if (aflag && nflag)
 332                 error("-a and -n options are incompatible");
 333
 334         if (tflag > 0)
 335                 thiszone = gmt2local(0);
 336
 337         if (RFileName != NULL) {
 338                 /*
 339                  * We don't need network access, so set it back to the user id.
 340                  * Also, this prevents the user from reading anyone's
 341                  * trace file.
 342                  */
 343                 setuid(getuid());
 344
 345                 pd = pcap_open_offline(RFileName, ebuf);
 346                 if (pd == NULL)
 347                         error("%s", ebuf);
 348                 localnet = 0;
 349                 netmask = 0;
 350                 if (fflag != 0)
 351                         error("-f and -r options are incompatible");
 352         } else {
 353                 if (device == NULL) {
 354                         device = pcap_lookupdev(ebuf);
 355                         if (device == NULL)
 356                                 error("%s", ebuf);
 357                 }
 358                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 359                 if (pd == NULL)
 360                         error("%s", ebuf);
 361                 i = pcap_snapshot(pd);
 362                 if (snaplen < i) {
 363                         warning("snaplen raised from %d to %d", snaplen, i);
 364                         snaplen = i;
 365                 }
 366                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 367                         localnet = 0;
 368                         netmask = 0;
 369                         warning("%s", ebuf);
 370                 }
 371                 /*
 372                  * Let user own process after socket has been opened.
 373                  */
 374                 setuid(getuid());
 375         }
 376         if (infile)
 377                 cmdbuf = read_infile(infile);
 378         else
 379                 cmdbuf = copy_argv(&argv[optind]);
 380
 381         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 382                 error("%s", pcap_geterr(pd));
 383         if (dflag) {
 384                 bpf_dump(&fcode, dflag);
 385                 exit(0);
 386         }
 387         init_addrtoname(localnet, netmask);
 388
 389         (void)setsignal(SIGTERM, cleanup);
 390         (void)setsignal(SIGINT, cleanup);
 391         /* Cooperate with nohup(1) */
 392         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 393                 (void)setsignal(SIGHUP, oldhandler);
 394
 395         if (pcap_setfilter(pd, &fcode) < 0)
 396                 error("%s", pcap_geterr(pd));
 397         if (WFileName) {
 398                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 399                 if (p == NULL)
 400                         error("%s", pcap_geterr(pd));
 401                 printer = pcap_dump;
 402                 pcap_userdata = (u_char *)p;
 403         } else {
 404                 printer = lookup_printer(pcap_datalink(pd));
 405                 pcap_userdata = 0;
 406         }
 407         if (RFileName == NULL) {
 408                 (void)fprintf(stderr, "%s: listening on %s\n",
 409                     program_name, device);
 410                 (void)fflush(stderr);
 411         }
 412         if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) {
 413                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 414                     program_name, pcap_geterr(pd));
 415                 exit(1);
 416         }
 417         pcap_close(pd);
 418         exit(0);
 419 }
 420
 421 /* make a clean exit on interrupts */
 422 RETSIGTYPE
 423 cleanup(int signo)
 424 {
 425         struct pcap_stat stat;
 426
 427         /* Can't print the summary if reading from a savefile */
 428         if (pd != NULL && pcap_file(pd) == NULL) {
 429                 (void)fflush(stdout);
 430                 putc('\n', stderr);
 431                 if (pcap_stats(pd, &stat) < 0)
 432                         (void)fprintf(stderr, "pcap_stats: %s\n",
 433                             pcap_geterr(pd));
 434                 else {
 435                         (void)fprintf(stderr, "%d packets received by filter\n",
 436                             stat.ps_recv);
 437                         (void)fprintf(stderr, "%d packets dropped by kernel\n",
 438                             stat.ps_drop);
 439                 }
 440         }
 441         exit(0);
 442 }
 443
 444 /* Like default_print() but data need not be aligned */
 445 void
 446 default_print_unaligned(register const u_char *cp, register u_int length)
 447 {
 448 #if 1
 449         register u_int i, s;
 450         register int nshorts;
 451
 452         nshorts = (u_int) length / sizeof(u_short);
 453         i = 0;
 454         while (--nshorts >= 0) {
 455                 if ((i++ % 8) == 0)
 456                         (void)printf("\n\t\t\t");
 457                 s = *cp++;
 458                 (void)printf(" %02x%02x", s, *cp++);
 459         }
 460         if (length & 1) {
 461                 if ((i % 8) == 0)
 462                         (void)printf("\n\t\t\t");
 463                 (void)printf(" %02x", *cp);
 464         }
 465 #else
 466   register u_int i;
 467   register int nshorts;
 468
 469   char line[81];
 470
 471   nshorts = (u_int) length / sizeof(u_short);
 472   i = 0;
 473   memset(line, ' ', 80);
 474   line[81]='\0';
 475
 476   putchar('\n');
 477   while (nshorts >= 0) {
 478
 479     sprintf(line+20+i*5, "%02x%02x  ", cp[0], cp[1]);
 480
 481     if(isprint(cp[0])) {
 482       line[62+i*2]=cp[0];
 483     } else {
 484       line[62+i*2]='.';
 485     }
 486     if(isprint(cp[1])) {
 487       line[62+i*2+1]=cp[1];
 488     } else {
 489       line[62+i*2+1]='.';
 490     }
 491     i++;
 492     if (i == 8) {
 493       line[60]=' ';
 494       line[61]=' ';
 495       line[62+16]='\0';
 496       puts(line);
 497       i=0;
 498     }
 499     cp += 2;
 500     nshorts--;
 501   }
 502 #endif
 503 }
 504
 505 /*
 506  * By default, print the packet out in hex.
 507  *
 508  * (BTW, please don't send us patches to print the packet out in ascii)
 509  */
 510 void
 511 default_print(register const u_char *bp, register u_int length)
 512 {
 513         default_print_unaligned(bp, length);
 514 }
 515
 516 __dead void
 517 usage(void)
 518 {
 519         extern char version[];
 520         extern char pcap_version[];
 521
 522         (void)fprintf(stderr, "%s version %s\n", program_name, version);
 523         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
 524         (void)fprintf(stderr,
 525 "Usage: %s [-adeflnNOpqStvx] [-c count] [ -F file ]\n", program_name);
 526         (void)fprintf(stderr,
 527 "\t\t[ -i interface ] [ -r file ] [ -s snaplen ]\n");
 528         (void)fprintf(stderr,
 529 "\t\t[ -T type ] [ -w file ] [ expression ]\n");
 530         exit(-1);
 531 }