1 /* $OpenBSD: tcpdump.c,v 1.80 2017/09/08 19:10:57 brynet Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 24 /* 25 * tcpdump - monitor tcp/ip traffic on an ethernet. 26 * 27 * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory. 28 * Mercilessly hacked and occasionally improved since then via the 29 * combined efforts of Van, Steve McCanne and Craig Leres of LBL. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/time.h> 34 #include <sys/ioctl.h> 35 #include <sys/wait.h> 36 37 #include <netinet/in.h> 38 39 #include <pcap.h> 40 #include <signal.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <limits.h> 46 #include <ctype.h> 47 #include <err.h> 48 #include <errno.h> 49 50 #include "interface.h" 51 #include "addrtoname.h" 52 #include "setsignal.h" 53 #include "gmt2local.h" 54 55 #include <sys/socket.h> 56 #include <net/if.h> 57 #include <net/pfvar.h> 58 #include "pfctl.h" 59 #include "pfctl_parser.h" 60 #include "privsep.h" 61 62 int Aflag; /* dump ascii */ 63 int aflag; /* translate network and broadcast addresses */ 64 int dflag; /* print filter code */ 65 int eflag; /* print ethernet header */ 66 int fflag; /* don't translate "foreign" IP address */ 67 int Iflag; /* include interface in output */ 68 int Lflag; /* List available link types */ 69 int nflag; /* leave addresses as numbers */ 70 int Nflag; /* remove domains from printed host names */ 71 int Oflag = 1; /* run filter code optimizer */ 72 int oflag; /* print passive OS fingerprints */ 73 int pflag; /* don't go promiscuous */ 74 int qflag; /* quick (shorter) output */ 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 int Xflag; /* print packet in emacs-hexl style */ 80 81 int packettype; 82 83 char *program_name; 84 char *device = NULL; 85 86 int32_t thiszone; /* seconds offset from gmt to local time */ 87 88 extern volatile pid_t child_pid; 89 90 /* Externs */ 91 extern void bpf_dump(struct bpf_program *, int); 92 extern int esp_init(char *); 93 94 /* Forwards */ 95 void cleanup(int); 96 void gotchld(int); 97 extern __dead void usage(void); 98 99 /* Length of saved portion of packet. */ 100 int snaplen = 0; 101 102 struct printer { 103 pcap_handler f; 104 int type; 105 }; 106 107 /* XXX needed if using old bpf.h */ 108 #ifndef DLT_ATM_RFC1483 109 #define DLT_ATM_RFC1483 11 110 #endif 111 112 static struct printer printers[] = { 113 { ether_if_print, DLT_EN10MB }, 114 { ether_if_print, DLT_IEEE802 }, 115 { sl_if_print, DLT_SLIP }, 116 { sl_bsdos_if_print, DLT_SLIP_BSDOS }, 117 { ppp_if_print, DLT_PPP }, 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 { loop_if_print, DLT_LOOP }, 123 { enc_if_print, DLT_ENC }, 124 { pflog_if_print, DLT_PFLOG }, 125 { pfsync_if_print, DLT_PFSYNC }, 126 { ppp_ether_if_print, DLT_PPP_ETHER }, 127 { ieee802_11_if_print, DLT_IEEE802_11 }, 128 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 129 { ofp_if_print, DLT_OPENFLOW }, 130 { NULL, 0 }, 131 }; 132 133 static pcap_handler 134 lookup_printer(int type) 135 { 136 struct printer *p; 137 138 for (p = printers; p->f; ++p) { 139 if (type == p->type) 140 return p->f; 141 } 142 143 error("unknown data link type 0x%x", type); 144 /* NOTREACHED */ 145 } 146 147 static int 148 init_pfosfp(void) 149 { 150 pf_osfp_initialize(); 151 if (pfctl_file_fingerprints(-1, 152 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 153 return 1; 154 return 0; 155 } 156 157 static pcap_t *pd; 158 159 /* Multiple DLT support */ 160 void pcap_list_linktypes(pcap_t *); 161 void pcap_print_linktype(u_int); 162 163 void 164 pcap_print_linktype(u_int dlt) 165 { 166 const char *name; 167 168 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 169 fprintf(stderr, "%s\n", name); 170 else 171 fprintf(stderr, "<unknown: %u>\n", dlt); 172 } 173 174 void 175 pcap_list_linktypes(pcap_t *p) 176 { 177 int fd = p->fd; 178 u_int n; 179 180 #define MAXDLT 100 181 182 u_int dltlist[MAXDLT]; 183 struct bpf_dltlist dl = {MAXDLT, dltlist}; 184 185 if (fd < 0) 186 error("Invalid bpf descriptor"); 187 188 if (ioctl(fd, BIOCGDLTLIST, &dl) < 0) 189 err(1, "BIOCGDLTLIST"); 190 191 if (dl.bfl_len > MAXDLT) 192 error("Invalid number of linktypes: %u", dl.bfl_len); 193 194 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 195 dl.bfl_len == 1 ? "" : "s"); 196 197 for (n = 0; n < dl.bfl_len; n++) { 198 fprintf(stderr, "\t"); 199 pcap_print_linktype(dltlist[n]); 200 } 201 } 202 203 int 204 main(int argc, char **argv) 205 { 206 int cnt = -1, op, i; 207 bpf_u_int32 localnet, netmask; 208 char *cp, *infile = NULL, *RFileName = NULL; 209 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 210 pcap_handler printer; 211 struct bpf_program *fcode; 212 u_char *pcap_userdata; 213 u_int dirfilt = 0, dlt = (u_int) -1; 214 const char *errstr; 215 216 if ((cp = strrchr(argv[0], '/')) != NULL) 217 program_name = cp + 1; 218 else 219 program_name = argv[0]; 220 221 /* '-P' used internally, exec privileged portion */ 222 if (argc >= 2 && strcmp("-P", argv[1]) == 0) 223 priv_exec(argc, argv); 224 225 if (priv_init(argc, argv)) 226 error("Failed to setup privsep"); 227 228 /* state: STATE_INIT */ 229 230 opterr = 0; 231 while ((op = getopt(argc, argv, 232 "Aac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 233 switch (op) { 234 235 case 'A': 236 xflag = 1; 237 Aflag = 1; 238 break; 239 240 case 'a': 241 aflag = 1; 242 break; 243 244 case 'c': 245 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 246 if (errstr) 247 error("invalid packet count %s: %s", 248 optarg, errstr); 249 break; 250 251 case 'D': 252 if (strcasecmp(optarg, "in") == 0) 253 dirfilt = BPF_DIRECTION_OUT; 254 else if (strcasecmp(optarg, "out") == 0) 255 dirfilt = BPF_DIRECTION_IN; 256 else 257 error("invalid traffic direction %s", optarg); 258 break; 259 260 case 'd': 261 ++dflag; 262 break; 263 case 'e': 264 eflag = 1; 265 break; 266 267 case 'f': 268 fflag = 1; 269 break; 270 271 case 'F': 272 infile = optarg; 273 break; 274 275 case 'i': 276 device = optarg; 277 break; 278 279 case 'I': 280 Iflag = 1; 281 break; 282 283 case 'l': 284 setvbuf(stdout, NULL, _IOLBF, 0); 285 break; 286 case 'L': 287 Lflag = 1; 288 break; 289 case 'n': 290 nflag = 1; 291 break; 292 293 case 'N': 294 Nflag = 1; 295 break; 296 297 case 'O': 298 Oflag = 0; 299 break; 300 301 case 'o': 302 oflag = 1; 303 break; 304 305 case 'p': 306 pflag = 1; 307 break; 308 309 case 'q': 310 qflag = 1; 311 break; 312 313 case 'r': 314 RFileName = optarg; 315 break; 316 317 case 's': 318 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 319 if (errstr) 320 error("invalid snaplen %s: %s", optarg, errstr); 321 break; 322 323 case 'S': 324 Sflag = 1; 325 break; 326 327 case 't': 328 --tflag; 329 break; 330 331 case 'T': 332 if (strcasecmp(optarg, "vat") == 0) 333 packettype = PT_VAT; 334 else if (strcasecmp(optarg, "wb") == 0) 335 packettype = PT_WB; 336 else if (strcasecmp(optarg, "rpc") == 0) 337 packettype = PT_RPC; 338 else if (strcasecmp(optarg, "rtp") == 0) 339 packettype = PT_RTP; 340 else if (strcasecmp(optarg, "rtcp") == 0) 341 packettype = PT_RTCP; 342 else if (strcasecmp(optarg, "cnfp") == 0) 343 packettype = PT_CNFP; 344 else if (strcasecmp(optarg, "vrrp") == 0) 345 packettype = PT_VRRP; 346 else if (strcasecmp(optarg, "tcp") == 0) 347 packettype = PT_TCP; 348 else if (strcasecmp(optarg, "sack") == 0) 349 /* 350 * kept for compatibility; DEFAULT_SNAPLEN 351 * used to be too short to capture SACK. 352 */ 353 ; 354 else 355 error("unknown packet type `%s'", optarg); 356 break; 357 358 case 'v': 359 ++vflag; 360 break; 361 362 case 'w': 363 WFileName = optarg; 364 break; 365 #ifdef YYDEBUG 366 case 'Y': 367 { 368 /* Undocumented flag */ 369 extern int yydebug; 370 yydebug = 1; 371 } 372 break; 373 #endif 374 case 'y': 375 i = pcap_datalink_name_to_val(optarg); 376 if (i < 0) 377 error("invalid data link type: %s", optarg); 378 dlt = (u_int)i; 379 break; 380 381 case 'x': 382 xflag = 1; 383 break; 384 385 case 'X': 386 Xflag = 1; 387 xflag = 1; 388 break; 389 390 case 'E': 391 if (esp_init(optarg) < 0) 392 error("bad esp specification `%s'", optarg); 393 break; 394 395 default: 396 usage(); 397 /* NOTREACHED */ 398 } 399 400 if (snaplen == 0) { 401 switch (dlt) { 402 case DLT_IEEE802_11: 403 snaplen = IEEE802_11_SNAPLEN; 404 break; 405 case DLT_IEEE802_11_RADIO: 406 snaplen = IEEE802_11_RADIO_SNAPLEN; 407 break; 408 default: 409 snaplen = DEFAULT_SNAPLEN; 410 break; 411 } 412 } 413 414 if (aflag && nflag) 415 error("-a and -n options are incompatible"); 416 417 if (RFileName != NULL) { 418 pd = priv_pcap_offline(RFileName, ebuf); 419 if (pd == NULL) 420 error("%s", ebuf); 421 /* state: STATE_BPF */ 422 localnet = 0; 423 netmask = 0; 424 if (fflag != 0) 425 error("-f and -r options are incompatible"); 426 } else { 427 if (device == NULL) { 428 device = pcap_lookupdev(ebuf); 429 if (device == NULL) 430 error("%s", ebuf); 431 } 432 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 433 dlt, dirfilt); 434 if (pd == NULL) 435 error("%s", ebuf); 436 437 /* state: STATE_BPF */ 438 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 439 if (fflag) 440 warning("%s", ebuf); 441 localnet = 0; 442 netmask = 0; 443 } 444 } 445 i = pcap_snapshot(pd); 446 if (snaplen < i) { 447 warning("snaplen raised from %d to %d", snaplen, i); 448 snaplen = i; 449 } 450 451 if (Lflag) { 452 pcap_list_linktypes(pd); 453 exit(0); 454 } 455 456 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 457 /* state: STATE_FILTER */ 458 if (fcode == NULL) 459 error("%s", pcap_geterr(pd)); 460 if (dflag) { 461 bpf_dump(fcode, dflag); 462 exit(0); 463 } 464 init_addrtoname(localnet, netmask); 465 466 if (WFileName) { 467 pcap_dumper_t *p; 468 469 p = priv_pcap_dump_open(pd, WFileName); 470 /* state: STATE_RUN */ 471 if (p == NULL) 472 error("%s", pcap_geterr(pd)); 473 { 474 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 475 fflush(fp); 476 setvbuf(fp, NULL, _IONBF, 0); 477 } 478 printer = pcap_dump; 479 pcap_userdata = (u_char *)p; 480 } else { 481 printer = lookup_printer(pcap_datalink(pd)); 482 pcap_userdata = NULL; 483 priv_init_done(); 484 /* state: STATE_RUN */ 485 } 486 if (RFileName == NULL) { 487 (void)fprintf(stderr, "%s: listening on %s, link-type ", 488 program_name, device); 489 pcap_print_linktype(pd->linktype); 490 (void)fflush(stderr); 491 } 492 493 if (oflag) 494 oflag = init_pfosfp(); 495 if (tflag > 0) 496 thiszone = gmt2local(0); 497 498 if (pledge("stdio", NULL) == -1) 499 err(1, "pledge"); 500 501 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 502 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 503 program_name, pcap_geterr(pd)); 504 exit(1); 505 } 506 pcap_close(pd); 507 exit(0); 508 } 509 510 /* make a clean exit on interrupts */ 511 void 512 cleanup(int signo) 513 { 514 struct pcap_stat stat; 515 sigset_t allsigs; 516 char buf[1024]; 517 518 sigfillset(&allsigs); 519 sigprocmask(SIG_BLOCK, &allsigs, NULL); 520 521 /* Can't print the summary if reading from a savefile */ 522 (void)write(STDERR_FILENO, "\n", 1); 523 if (pd != NULL && pcap_file(pd) == NULL) { 524 if (priv_pcap_stats(&stat) < 0) { 525 (void)snprintf(buf, sizeof buf, 526 "pcap_stats: %s\n", pcap_geterr(pd)); 527 write(STDERR_FILENO, buf, strlen(buf)); 528 } else { 529 (void)snprintf(buf, sizeof buf, 530 "%u packets received by filter\n", stat.ps_recv); 531 write(STDERR_FILENO, buf, strlen(buf)); 532 (void)snprintf(buf, sizeof buf, 533 "%u packets dropped by kernel\n", stat.ps_drop); 534 write(STDERR_FILENO, buf, strlen(buf)); 535 } 536 } 537 _exit(0); 538 } 539 540 void 541 gotchld(int signo) 542 { 543 pid_t pid; 544 int status; 545 int save_err = errno; 546 547 do { 548 pid = waitpid(child_pid, &status, WNOHANG); 549 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 550 cleanup(0); 551 } while (pid == -1 && errno == EINTR); 552 553 if (pid == -1) 554 _exit(1); 555 556 errno = save_err; 557 } 558 559 /* dump the buffer in `emacs-hexl' style */ 560 void 561 default_print_hexl(const u_char *cp, unsigned int length) 562 { 563 unsigned int i, j, jm; 564 int c; 565 char ln[128], buf[128]; 566 567 printf("\n"); 568 for (i = 0; i < length; i += 0x10) { 569 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 570 jm = length - i; 571 jm = jm > 16 ? 16 : jm; 572 573 for (j = 0; j < jm; j++) { 574 if ((j % 2) == 1) 575 snprintf(buf, sizeof(buf), "%02x ", 576 (unsigned int)cp[i+j]); 577 else 578 snprintf(buf, sizeof(buf), "%02x", 579 (unsigned int)cp[i+j]); 580 strlcat(ln, buf, sizeof ln); 581 } 582 for (; j < 16; j++) { 583 if ((j % 2) == 1) 584 snprintf(buf, sizeof buf, " "); 585 else 586 snprintf(buf, sizeof buf, " "); 587 strlcat(ln, buf, sizeof ln); 588 } 589 590 strlcat(ln, " ", sizeof ln); 591 for (j = 0; j < jm; j++) { 592 c = cp[i+j]; 593 c = isprint(c) ? c : '.'; 594 buf[0] = c; 595 buf[1] = '\0'; 596 strlcat(ln, buf, sizeof ln); 597 } 598 printf("%s\n", ln); 599 } 600 } 601 602 /* dump the text from the buffer */ 603 void 604 default_print_ascii(const u_char *cp, unsigned int length) 605 { 606 int c, i; 607 608 printf("\n"); 609 for (i = 0; i < length; i++) { 610 c = cp[i]; 611 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 612 putchar(c); 613 else 614 putchar('.'); 615 } 616 } 617 618 /* Like default_print() but data need not be aligned */ 619 void 620 default_print_unaligned(const u_char *cp, u_int length) 621 { 622 u_int i, s; 623 int nshorts; 624 625 if (Xflag) { 626 /* dump the buffer in `emacs-hexl' style */ 627 default_print_hexl(cp, length); 628 } else if (Aflag) { 629 /* dump the text in the buffer */ 630 default_print_ascii(cp, length); 631 } else { 632 /* dump the buffer in old tcpdump style */ 633 nshorts = (u_int) length / sizeof(u_short); 634 i = 0; 635 while (--nshorts >= 0) { 636 if ((i++ % 8) == 0) 637 (void)printf("\n\t\t\t"); 638 s = *cp++; 639 (void)printf(" %02x%02x", s, *cp++); 640 } 641 if (length & 1) { 642 if ((i % 8) == 0) 643 (void)printf("\n\t\t\t"); 644 (void)printf(" %02x", *cp); 645 } 646 } 647 } 648 649 void 650 default_print(const u_char *bp, u_int length) 651 { 652 const u_short *sp; 653 u_int i; 654 int nshorts; 655 656 if (Xflag) { 657 /* dump the buffer in `emacs-hexl' style */ 658 default_print_hexl(bp, length); 659 } else if (Aflag) { 660 /* dump the text in the buffer */ 661 default_print_ascii(bp, length); 662 } else { 663 /* dump the buffer in old tcpdump style */ 664 if ((long)bp & 1) { 665 default_print_unaligned(bp, length); 666 return; 667 } 668 sp = (u_short *)bp; 669 nshorts = (u_int) length / sizeof(u_short); 670 i = 0; 671 while (--nshorts >= 0) { 672 if ((i++ % 8) == 0) 673 (void)printf("\n\t\t\t"); 674 (void)printf(" %04x", ntohs(*sp++)); 675 } 676 if (length & 1) { 677 if ((i % 8) == 0) 678 (void)printf("\n\t\t\t"); 679 (void)printf(" %02x", *(u_char *)sp); 680 } 681 } 682 } 683 684 void 685 set_slave_signals(void) 686 { 687 setsignal(SIGTERM, cleanup); 688 setsignal(SIGINT, cleanup); 689 setsignal(SIGCHLD, gotchld); 690 setsignal(SIGHUP, cleanup); 691 } 692 693 __dead void 694 usage(void) 695 { 696 (void)fprintf(stderr, 697 "Usage: %s [-AadefILlNnOopqStvXx] [-c count] [-D direction]\n", 698 program_name); 699 (void)fprintf(stderr, 700 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 701 (void)fprintf(stderr, 702 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 703 exit(1); 704 } 705