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 1.134 1999-11-21 03:50:26 assar 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 #include <sys/types.h>
  39 #include <sys/time.h>
  40
  41 #include <netinet/in.h>
  42
  43 #include <pcap.h>
  44 #include <signal.h>
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49
  50 #include <netinet/in_systm.h>
  51 #include <netinet/ip.h>
  52
  53 #include "interface.h"
  54 #include "addrtoname.h"
  55 #include "machdep.h"
  56 #include "setsignal.h"
  57 #include "gmt2local.h"
  58
  59 int aflag;                      /* translate network and broadcast addresses */
  60 int dflag;                      /* print filter code */
  61 int eflag;                      /* print ethernet header */
  62 int fflag;                      /* don't translate "foreign" IP address */
  63 int nflag;                      /* leave addresses as numbers */
  64 int Nflag;                      /* remove domains from printed host names */
  65 int Oflag = 1;                  /* run filter code optimizer */
  66 int pflag;                      /* don't go promiscuous */
  67 int qflag;                      /* quick (shorter) output */
  68 int Rflag = 1;                  /* print sequence # field in AH/ESP*/
  69 int Sflag;                      /* print raw TCP sequence numbers */
  70 int tflag = 1;                  /* print packet arrival time */
  71 int vflag;                      /* verbose */
  72 int xflag;                      /* print packet in hex */
  73
  74 char *ahsecret = NULL;          /* AH secret key */
  75 char *espsecret = NULL;         /* ESP secret key */
  76
  77 int packettype;
  78
  79
  80 char *program_name;
  81
  82 int32_t thiszone;               /* seconds offset from gmt to local time */
  83
  84 /* Externs */
  85 extern void bpf_dump(struct bpf_program *, int);
  86
  87 /* Forwards */
  88 RETSIGTYPE cleanup(int);
  89 extern __dead void usage(void) __attribute__((volatile));
  90
  91 /* Length of saved portion of packet. */
  92 int snaplen = DEFAULT_SNAPLEN;
  93
  94 struct printer {
  95         pcap_handler f;
  96         int type;
  97 };
  98
  99 static struct printer printers[] = {
 100         { ether_if_print,       DLT_EN10MB },
 101         { ether_if_print,       DLT_IEEE802 },
 102 #ifdef DLT_LANE8023
 103         { lane_if_print,        DLT_LANE8023 },
 104 #endif
 105 #ifdef DLT_CIP
 106         { cip_if_print,         DLT_CIP },
 107 #endif
 108         { sl_if_print,          DLT_SLIP },
 109         { sl_bsdos_if_print,    DLT_SLIP_BSDOS },
 110         { ppp_if_print,         DLT_PPP },
 111         { ppp_bsdos_if_print,   DLT_PPP_BSDOS },
 112         { fddi_if_print,        DLT_FDDI },
 113         { null_if_print,        DLT_NULL },
 114         { raw_if_print,         DLT_RAW },
 115         { atm_if_print,         DLT_ATM_RFC1483 },
 116 #ifdef DLT_CHDLC
 117         { chdlc_if_print,       DLT_CHDLC },
 118 #endif
 119         { NULL,                 0 },
 120 };
 121
 122 static pcap_handler
 123 lookup_printer(int type)
 124 {
 125         struct printer *p;
 126
 127         for (p = printers; p->f; ++p)
 128                 if (type == p->type)
 129                         return p->f;
 130
 131         error("unknown data link type 0x%x", type);
 132         /* NOTREACHED */
 133 }
 134
 135 static pcap_t *pd;
 136
 137 extern int optind;
 138 extern int opterr;
 139 extern char *optarg;
 140
 141 int
 142 main(int argc, char **argv)
 143 {
 144         register int cnt, op, i;
 145         bpf_u_int32 localnet, netmask;
 146         register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
 147         pcap_handler printer;
 148         struct bpf_program fcode;
 149         RETSIGTYPE (*oldhandler)(int);
 150         u_char *pcap_userdata;
 151         char ebuf[PCAP_ERRBUF_SIZE];
 152
 153         cnt = -1;
 154         device = NULL;
 155         infile = NULL;
 156         RFileName = NULL;
 157         WFileName = NULL;
 158         if ((cp = strrchr(argv[0], '/')) != NULL)
 159                 program_name = cp + 1;
 160         else
 161                 program_name = argv[0];
 162
 163         if (abort_on_misalignment(ebuf) < 0)
 164                 error("%s", ebuf);
 165
 166         opterr = 0;
 167         while (
 168             (op = getopt(argc, argv, "ac:deE:fF:i:lnNOpqr:Rs:StT:vw:xY")) != EOF)
 169                 switch (op) {
 170
 171                 case 'a':
 172                         ++aflag;
 173                         break;
 174
 175 #if 0
 176                 case 'A':
 177 #ifndef CRYPTO
 178                         warning("crypto code not compiled in");
 179 #endif
 180                         ahsecret = optarg;
 181                         break;
 182 #endif
 183
 184                 case 'c':
 185                         cnt = atoi(optarg);
 186                         if (cnt <= 0)
 187                                 error("invalid packet count %s", optarg);
 188                         break;
 189
 190                 case 'd':
 191                         ++dflag;
 192                         break;
 193
 194                 case 'e':
 195                         ++eflag;
 196                         break;
 197
 198                 case 'E':
 199 #ifndef CRYPTO
 200                         warning("crypto code not compiled in");
 201 #endif
 202                         espsecret = optarg;
 203                         break;
 204
 205                 case 'f':
 206                         ++fflag;
 207                         break;
 208
 209                 case 'F':
 210                         infile = optarg;
 211                         break;
 212
 213                 case 'i':
 214                         device = optarg;
 215                         break;
 216
 217                 case 'l':
 218 #ifdef HAVE_SETLINEBUF
 219                         setlinebuf(stdout);
 220 #else
 221                         setvbuf(stdout, NULL, _IOLBF, 0);
 222 #endif
 223                         break;
 224
 225                 case 'n':
 226                         ++nflag;
 227                         break;
 228
 229                 case 'N':
 230                         ++Nflag;
 231                         break;
 232
 233                 case 'O':
 234                         Oflag = 0;
 235                         break;
 236
 237                 case 'p':
 238                         ++pflag;
 239                         break;
 240
 241                 case 'q':
 242                         ++qflag;
 243                         break;
 244
 245                 case 'r':
 246                         RFileName = optarg;
 247                         break;
 248
 249                 case 'R':
 250                         Rflag = 0;
 251                         break;
 252
 253                 case 's':
 254                         snaplen = atoi(optarg);
 255                         if (snaplen <= 0)
 256                                 error("invalid snaplen %s", optarg);
 257                         break;
 258
 259                 case 'S':
 260                         ++Sflag;
 261                         break;
 262
 263                 case 't':
 264                         --tflag;
 265                         break;
 266
 267                 case 'T':
 268                         if (strcasecmp(optarg, "vat") == 0)
 269                                 packettype = PT_VAT;
 270                         else if (strcasecmp(optarg, "wb") == 0)
 271                                 packettype = PT_WB;
 272                         else if (strcasecmp(optarg, "rpc") == 0)
 273                                 packettype = PT_RPC;
 274                         else if (strcasecmp(optarg, "rtp") == 0)
 275                                 packettype = PT_RTP;
 276                         else if (strcasecmp(optarg, "rtcp") == 0)
 277                                 packettype = PT_RTCP;
 278                         else if (strcasecmp(optarg, "snmp") == 0)
 279                                 packettype = PT_SNMP;
 280                         else
 281                                 error("unknown packet type `%s'", optarg);
 282                         break;
 283
 284                 case 'v':
 285                         ++vflag;
 286                         break;
 287
 288                 case 'w':
 289                         WFileName = optarg;
 290                         break;
 291 #ifdef YYDEBUG
 292                 case 'Y':
 293                         {
 294                         /* Undocumented flag */
 295                         extern int yydebug;
 296                         yydebug = 1;
 297                         }
 298                         break;
 299 #endif
 300                 case 'x':
 301                         ++xflag;
 302                         break;
 303
 304                 default:
 305                         usage();
 306                         /* NOTREACHED */
 307                 }
 308
 309         if (aflag && nflag)
 310                 error("-a and -n options are incompatible");
 311
 312         if (tflag > 0)
 313                 thiszone = gmt2local(0);
 314
 315         if (RFileName != NULL) {
 316                 /*
 317                  * We don't need network access, so set it back to the user id.
 318                  * Also, this prevents the user from reading anyone's
 319                  * trace file.
 320                  */
 321                 setuid(getuid());
 322
 323                 pd = pcap_open_offline(RFileName, ebuf);
 324                 if (pd == NULL)
 325                         error("%s", ebuf);
 326                 localnet = 0;
 327                 netmask = 0;
 328                 if (fflag != 0)
 329                         error("-f and -r options are incompatible");
 330         } else {
 331                 if (device == NULL) {
 332                         device = pcap_lookupdev(ebuf);
 333                         if (device == NULL)
 334                                 error("%s", ebuf);
 335                 }
 336                 pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
 337                 if (pd == NULL)
 338                         error("%s", ebuf);
 339                 i = pcap_snapshot(pd);
 340                 if (snaplen < i) {
 341                         warning("snaplen raised from %d to %d", snaplen, i);
 342                         snaplen = i;
 343                 }
 344                 if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
 345                         localnet = 0;
 346                         netmask = 0;
 347                         warning("%s", ebuf);
 348                 }
 349                 /*
 350                  * Let user own process after socket has been opened.
 351                  */
 352                 setuid(getuid());
 353         }
 354         if (infile)
 355                 cmdbuf = read_infile(infile);
 356         else
 357                 cmdbuf = copy_argv(&argv[optind]);
 358
 359         if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
 360                 error("%s", pcap_geterr(pd));
 361         if (dflag) {
 362                 bpf_dump(&fcode, dflag);
 363                 exit(0);
 364         }
 365         init_addrtoname(localnet, netmask);
 366
 367         (void)setsignal(SIGTERM, cleanup);
 368         (void)setsignal(SIGINT, cleanup);
 369         /* Cooperate with nohup(1) */
 370         if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
 371                 (void)setsignal(SIGHUP, oldhandler);
 372
 373         if (pcap_setfilter(pd, &fcode) < 0)
 374                 error("%s", pcap_geterr(pd));
 375         if (WFileName) {
 376                 pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
 377                 if (p == NULL)
 378                         error("%s", pcap_geterr(pd));
 379                 printer = pcap_dump;
 380                 pcap_userdata = (u_char *)p;
 381         } else {
 382                 printer = lookup_printer(pcap_datalink(pd));
 383                 pcap_userdata = 0;
 384         }
 385         if (RFileName == NULL) {
 386                 (void)fprintf(stderr, "%s: listening on %s\n",
 387                     program_name, device);
 388                 (void)fflush(stderr);
 389         }
 390         if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) {
 391                 (void)fprintf(stderr, "%s: pcap_loop: %s\n",
 392                     program_name, pcap_geterr(pd));
 393                 exit(1);
 394         }
 395         pcap_close(pd);
 396         exit(0);
 397 }
 398
 399 /* make a clean exit on interrupts */
 400 RETSIGTYPE
 401 cleanup(int signo)
 402 {
 403         struct pcap_stat stat;
 404
 405         /* Can't print the summary if reading from a savefile */
 406         if (pd != NULL && pcap_file(pd) == NULL) {
 407                 (void)fflush(stdout);
 408                 putc('\n', stderr);
 409                 if (pcap_stats(pd, &stat) < 0)
 410                         (void)fprintf(stderr, "pcap_stats: %s\n",
 411                             pcap_geterr(pd));
 412                 else {
 413                         (void)fprintf(stderr, "%d packets received by filter\n",
 414                             stat.ps_recv);
 415                         (void)fprintf(stderr, "%d packets dropped by kernel\n",
 416                             stat.ps_drop);
 417                 }
 418         }
 419         exit(0);
 420 }
 421
 422 /* Like default_print() but data need not be aligned */
 423 void
 424 default_print_unaligned(register const u_char *cp, register u_int length)
 425 {
 426   register u_int i, s;
 427   register int nshorts;
 428
 429   char line[81];
 430
 431   nshorts = (u_int) length / sizeof(u_short);
 432   i = 0;
 433   memset(line, ' ', 80);
 434   line[81]='\0';
 435
 436   putchar('\n');
 437   while (nshorts >= 0) {
 438
 439     sprintf(line+20+i*5, "%02x%02x  ", cp[0], cp[1]);
 440
 441     if(isprint(cp[0])) {
 442       line[62+i*2]=cp[0];
 443     } else {
 444       line[62+i*2]='.';
 445     }
 446     if(isprint(cp[1])) {
 447       line[62+i*2+1]=cp[1];
 448     } else {
 449       line[62+i*2+1]='.';
 450     }
 451     i++;
 452     if (i == 8) {
 453       line[60]=' ';
 454       line[61]=' ';
 455       line[62+16]='\0';
 456       puts(line);
 457       i=0;
 458     }
 459     cp += 2;
 460     nshorts--;
 461   }
 462 }
 463
 464 /*
 465  * By default, print the packet out in hex.
 466  *
 467  * (BTW, please don't send us patches to print the packet out in ascii)
 468  */
 469 void
 470 default_print(register const u_char *bp, register u_int length)
 471 {
 472         register const u_short *sp;
 473         register u_int i;
 474         register int nshorts;
 475
 476         default_print_unaligned(bp, length);
 477 }
 478
 479 __dead void
 480 usage(void)
 481 {
 482         extern char version[];
 483         extern char pcap_version[];
 484
 485         (void)fprintf(stderr, "%s version %s\n", program_name, version);
 486         (void)fprintf(stderr, "libpcap version %s\n", pcap_version);
 487         (void)fprintf(stderr,
 488 "Usage: %s [-adeflnNOpqStvx] [-c count] [ -F file ]\n", program_name);
 489         (void)fprintf(stderr,
 490 "\t\t[ -i interface ] [ -r file ] [ -s snaplen ]\n");
 491         (void)fprintf(stderr,
 492 "\t\t[ -T type ] [ -w file ] [ expression ]\n");
 493         exit(-1);
 494 }