1 /* $OpenBSD: tcpdump.c,v 1.89 2019/03/18 00:09:22 dlg 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 Bflag; /* BPF fildrop setting */ 65 int dflag; /* print filter code */ 66 int eflag; /* print ethernet header */ 67 int fflag; /* don't translate "foreign" IP address */ 68 int Iflag; /* include interface in output */ 69 int Lflag; /* List available link types */ 70 int nflag; /* leave addresses as numbers */ 71 int Nflag; /* remove domains from printed host names */ 72 int Oflag = 1; /* run filter code optimizer */ 73 int oflag; /* print passive OS fingerprints */ 74 int pflag; /* don't go promiscuous */ 75 int qflag; /* quick (shorter) output */ 76 int Sflag; /* print raw TCP sequence numbers */ 77 int tflag = 1; /* print packet arrival time */ 78 int vflag; /* verbose */ 79 int xflag; /* print packet in hex */ 80 int Xflag; /* print packet in emacs-hexl style */ 81 82 int packettype; 83 84 char *program_name; 85 char *device = NULL; 86 87 int32_t thiszone; /* seconds offset from gmt to local time */ 88 89 extern volatile pid_t child_pid; 90 91 /* Externs */ 92 extern void bpf_dump(struct bpf_program *, int); 93 extern int esp_init(char *); 94 95 /* Forwards */ 96 void cleanup(int); 97 void gotchld(int); 98 extern __dead void usage(void); 99 100 /* Length of saved portion of packet. */ 101 int snaplen = 0; 102 103 struct printer { 104 pcap_handler f; 105 int type; 106 }; 107 108 /* XXX needed if using old bpf.h */ 109 #ifndef DLT_ATM_RFC1483 110 #define DLT_ATM_RFC1483 11 111 #endif 112 113 static struct printer printers[] = { 114 { ether_if_print, DLT_EN10MB }, 115 { ether_if_print, DLT_IEEE802 }, 116 { sl_if_print, DLT_SLIP }, 117 { sl_bsdos_if_print, DLT_SLIP_BSDOS }, 118 { ppp_if_print, DLT_PPP }, 119 { ppp_hdlc_if_print, DLT_PPP_SERIAL }, 120 { fddi_if_print, DLT_FDDI }, 121 { null_if_print, DLT_NULL }, 122 { raw_if_print, DLT_RAW }, 123 { atm_if_print, DLT_ATM_RFC1483 }, 124 { loop_if_print, DLT_LOOP }, 125 { enc_if_print, DLT_ENC }, 126 { pflog_if_print, DLT_PFLOG }, 127 { pfsync_if_print, DLT_PFSYNC }, 128 { ppp_ether_if_print, DLT_PPP_ETHER }, 129 { ieee802_11_if_print, DLT_IEEE802_11 }, 130 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 131 { ofp_if_print, DLT_OPENFLOW }, 132 { usbpcap_if_print, DLT_USBPCAP }, 133 { NULL, 0 }, 134 }; 135 136 static pcap_handler 137 lookup_printer(int type) 138 { 139 struct printer *p; 140 141 for (p = printers; p->f; ++p) { 142 if (type == p->type) 143 return p->f; 144 } 145 146 error("unknown data link type 0x%x", type); 147 /* NOTREACHED */ 148 } 149 150 static int 151 init_pfosfp(void) 152 { 153 pf_osfp_initialize(); 154 if (pfctl_file_fingerprints(-1, 155 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 156 return 1; 157 return 0; 158 } 159 160 static pcap_t *pd; 161 162 /* Multiple DLT support */ 163 void pcap_list_linktypes(pcap_t *); 164 void pcap_print_linktype(u_int); 165 166 void 167 pcap_print_linktype(u_int dlt) 168 { 169 const char *name; 170 171 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 172 fprintf(stderr, "%s\n", name); 173 else 174 fprintf(stderr, "<unknown: %u>\n", dlt); 175 } 176 177 void 178 pcap_list_linktypes(pcap_t *p) 179 { 180 int fd = p->fd; 181 u_int n; 182 183 #define MAXDLT 100 184 185 u_int dltlist[MAXDLT]; 186 struct bpf_dltlist dl = {MAXDLT, dltlist}; 187 188 if (fd < 0) 189 error("Invalid bpf descriptor"); 190 191 if (ioctl(fd, BIOCGDLTLIST, &dl) < 0) 192 err(1, "BIOCGDLTLIST"); 193 194 if (dl.bfl_len > MAXDLT) 195 error("Invalid number of linktypes: %u", dl.bfl_len); 196 197 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 198 dl.bfl_len == 1 ? "" : "s"); 199 200 for (n = 0; n < dl.bfl_len; n++) { 201 fprintf(stderr, "\t"); 202 pcap_print_linktype(dltlist[n]); 203 } 204 } 205 206 int 207 main(int argc, char **argv) 208 { 209 int cnt = -1, op, i; 210 bpf_u_int32 localnet, netmask; 211 char *cp, *infile = NULL, *RFileName = NULL; 212 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 213 pcap_handler printer; 214 struct bpf_program *fcode; 215 u_char *pcap_userdata; 216 u_int dirfilt = 0, dlt = (u_int) -1; 217 const char *errstr; 218 219 if ((cp = strrchr(argv[0], '/')) != NULL) 220 program_name = cp + 1; 221 else 222 program_name = argv[0]; 223 224 /* '-P' used internally, exec privileged portion */ 225 if (argc >= 2 && strcmp("-P", argv[1]) == 0) 226 priv_exec(argc, argv); 227 228 if (priv_init(argc, argv)) 229 error("Failed to setup privsep"); 230 231 /* state: STATE_INIT */ 232 233 opterr = 0; 234 while ((op = getopt(argc, argv, 235 "AaB:c:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 236 switch (op) { 237 238 case 'A': 239 xflag = 1; 240 Aflag = 1; 241 break; 242 243 case 'a': 244 aflag = 1; 245 break; 246 247 case 'B': 248 if (strcasecmp(optarg, "pass") == 0) 249 Bflag = BPF_FILDROP_PASS; 250 else if (strcasecmp(optarg, "capture") == 0) 251 Bflag = BPF_FILDROP_CAPTURE; 252 else if (strcasecmp(optarg, "drop") == 0) 253 Bflag = BPF_FILDROP_DROP; 254 else { 255 error("invalid BPF fildrop option: %s", 256 optarg); 257 } 258 break; 259 260 case 'c': 261 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 262 if (errstr) 263 error("invalid packet count %s: %s", 264 optarg, errstr); 265 break; 266 267 case 'D': 268 if (strcasecmp(optarg, "in") == 0) 269 dirfilt = BPF_DIRECTION_OUT; 270 else if (strcasecmp(optarg, "out") == 0) 271 dirfilt = BPF_DIRECTION_IN; 272 else 273 error("invalid traffic direction %s", optarg); 274 break; 275 276 case 'd': 277 ++dflag; 278 break; 279 case 'e': 280 eflag = 1; 281 break; 282 283 case 'f': 284 fflag = 1; 285 break; 286 287 case 'F': 288 infile = optarg; 289 break; 290 291 case 'i': 292 device = optarg; 293 break; 294 295 case 'I': 296 Iflag = 1; 297 break; 298 299 case 'l': 300 setvbuf(stdout, NULL, _IOLBF, 0); 301 break; 302 case 'L': 303 Lflag = 1; 304 break; 305 case 'n': 306 nflag = 1; 307 break; 308 309 case 'N': 310 Nflag = 1; 311 break; 312 313 case 'O': 314 Oflag = 0; 315 break; 316 317 case 'o': 318 oflag = 1; 319 break; 320 321 case 'p': 322 pflag = 1; 323 break; 324 325 case 'q': 326 qflag = 1; 327 break; 328 329 case 'r': 330 RFileName = optarg; 331 break; 332 333 case 's': 334 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 335 if (errstr) 336 error("invalid snaplen %s: %s", optarg, errstr); 337 break; 338 339 case 'S': 340 Sflag = 1; 341 break; 342 343 case 't': 344 --tflag; 345 break; 346 347 case 'T': 348 if (strcasecmp(optarg, "vat") == 0) 349 packettype = PT_VAT; 350 else if (strcasecmp(optarg, "wb") == 0) 351 packettype = PT_WB; 352 else if (strcasecmp(optarg, "rpc") == 0) 353 packettype = PT_RPC; 354 else if (strcasecmp(optarg, "rtp") == 0) 355 packettype = PT_RTP; 356 else if (strcasecmp(optarg, "rtcp") == 0) 357 packettype = PT_RTCP; 358 else if (strcasecmp(optarg, "cnfp") == 0) 359 packettype = PT_CNFP; 360 else if (strcasecmp(optarg, "vrrp") == 0) 361 packettype = PT_VRRP; 362 else if (strcasecmp(optarg, "tcp") == 0) 363 packettype = PT_TCP; 364 else if (strcasecmp(optarg, "gre") == 0) 365 packettype = PT_GRE; 366 else if (strcasecmp(optarg, "vxlan") == 0) 367 packettype = PT_VXLAN; 368 else if (strcasecmp(optarg, "mpls") == 0) 369 packettype = PT_MPLS; 370 else if (strcasecmp(optarg, "tftp") == 0) 371 packettype = PT_TFTP; 372 else if (strcasecmp(optarg, "sack") == 0) 373 /* 374 * kept for compatibility; DEFAULT_SNAPLEN 375 * used to be too short to capture SACK. 376 */ 377 ; 378 else 379 error("unknown packet type `%s'", optarg); 380 break; 381 382 case 'v': 383 ++vflag; 384 break; 385 386 case 'w': 387 WFileName = optarg; 388 break; 389 #ifdef YYDEBUG 390 case 'Y': 391 { 392 /* Undocumented flag */ 393 extern int yydebug; 394 yydebug = 1; 395 } 396 break; 397 #endif 398 case 'y': 399 i = pcap_datalink_name_to_val(optarg); 400 if (i < 0) 401 error("invalid data link type: %s", optarg); 402 dlt = (u_int)i; 403 break; 404 405 case 'x': 406 xflag = 1; 407 break; 408 409 case 'X': 410 Xflag = 1; 411 xflag = 1; 412 break; 413 414 case 'E': 415 if (esp_init(optarg) < 0) 416 error("bad esp specification `%s'", optarg); 417 break; 418 419 default: 420 usage(); 421 /* NOTREACHED */ 422 } 423 424 if (snaplen == 0) { 425 switch (dlt) { 426 case DLT_IEEE802_11: 427 snaplen = IEEE802_11_SNAPLEN; 428 break; 429 case DLT_IEEE802_11_RADIO: 430 snaplen = IEEE802_11_RADIO_SNAPLEN; 431 break; 432 default: 433 snaplen = DEFAULT_SNAPLEN; 434 break; 435 } 436 } 437 438 if (aflag && nflag) 439 error("-a and -n options are incompatible"); 440 441 if (RFileName != NULL) { 442 pd = priv_pcap_offline(RFileName, ebuf); 443 if (pd == NULL) 444 error("%s", ebuf); 445 /* state: STATE_BPF */ 446 localnet = 0; 447 netmask = 0; 448 if (fflag != 0) 449 error("-f and -r options are incompatible"); 450 } else { 451 if (device == NULL) { 452 device = pcap_lookupdev(ebuf); 453 if (device == NULL) 454 error("%s", ebuf); 455 } 456 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 457 dlt, dirfilt, Bflag); 458 if (pd == NULL) 459 error("%s", ebuf); 460 461 /* state: STATE_BPF */ 462 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 463 if (fflag) 464 warning("%s", ebuf); 465 localnet = 0; 466 netmask = 0; 467 } 468 } 469 i = pcap_snapshot(pd); 470 if (snaplen < i) { 471 warning("snaplen raised from %d to %d", snaplen, i); 472 snaplen = i; 473 } 474 475 if (Lflag) { 476 pcap_list_linktypes(pd); 477 exit(0); 478 } 479 480 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 481 /* state: STATE_FILTER */ 482 if (fcode == NULL) 483 error("%s", pcap_geterr(pd)); 484 if (dflag) { 485 bpf_dump(fcode, dflag); 486 exit(0); 487 } 488 if (oflag) 489 oflag = init_pfosfp(); 490 init_addrtoname(localnet, netmask); 491 492 if (WFileName) { 493 pcap_dumper_t *p; 494 495 p = priv_pcap_dump_open(pd, WFileName); 496 /* state: STATE_RUN */ 497 if (p == NULL) 498 error("%s", pcap_geterr(pd)); 499 { 500 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 501 fflush(fp); 502 setvbuf(fp, NULL, _IONBF, 0); 503 } 504 printer = pcap_dump; 505 pcap_userdata = (u_char *)p; 506 } else { 507 printer = lookup_printer(pcap_datalink(pd)); 508 pcap_userdata = NULL; 509 priv_init_done(); 510 /* state: STATE_RUN */ 511 } 512 if (RFileName == NULL) { 513 (void)fprintf(stderr, "%s: listening on %s, link-type ", 514 program_name, device); 515 pcap_print_linktype(pd->linktype); 516 (void)fflush(stderr); 517 } 518 519 if (tflag > 0) 520 thiszone = gmt2local(0); 521 522 if (pledge("stdio", NULL) == -1) 523 err(1, "pledge"); 524 525 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 526 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 527 program_name, pcap_geterr(pd)); 528 exit(1); 529 } 530 pcap_close(pd); 531 exit(0); 532 } 533 534 /* make a clean exit on interrupts */ 535 void 536 cleanup(int signo) 537 { 538 struct pcap_stat stat; 539 sigset_t allsigs; 540 541 sigfillset(&allsigs); 542 sigprocmask(SIG_BLOCK, &allsigs, NULL); 543 544 /* Can't print the summary if reading from a savefile */ 545 dprintf(STDERR_FILENO, "\n"); 546 if (pd != NULL && pcap_file(pd) == NULL) { 547 if (priv_pcap_stats(&stat) < 0) { 548 dprintf(STDERR_FILENO, 549 "pcap_stats: %s\n", pcap_geterr(pd)); 550 } else { 551 dprintf(STDERR_FILENO, 552 "%u packets received by filter\n", stat.ps_recv); 553 dprintf(STDERR_FILENO, 554 "%u packets dropped by kernel\n", stat.ps_drop); 555 } 556 } 557 _exit(0); 558 } 559 560 void 561 gotchld(int signo) 562 { 563 pid_t pid; 564 int status; 565 int save_err = errno; 566 567 do { 568 pid = waitpid(child_pid, &status, WNOHANG); 569 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 570 cleanup(0); 571 } while (pid == -1 && errno == EINTR); 572 573 if (pid == -1) 574 _exit(1); 575 576 errno = save_err; 577 } 578 579 /* dump the buffer in `emacs-hexl' style */ 580 void 581 default_print_hexl(const u_char *cp, unsigned int length) 582 { 583 unsigned int i, j, jm; 584 int c; 585 char ln[128], buf[128]; 586 587 printf("\n"); 588 for (i = 0; i < length; i += 0x10) { 589 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 590 jm = length - i; 591 jm = jm > 16 ? 16 : jm; 592 593 for (j = 0; j < jm; j++) { 594 if ((j % 2) == 1) 595 snprintf(buf, sizeof(buf), "%02x ", 596 (unsigned int)cp[i+j]); 597 else 598 snprintf(buf, sizeof(buf), "%02x", 599 (unsigned int)cp[i+j]); 600 strlcat(ln, buf, sizeof ln); 601 } 602 for (; j < 16; j++) { 603 if ((j % 2) == 1) 604 snprintf(buf, sizeof buf, " "); 605 else 606 snprintf(buf, sizeof buf, " "); 607 strlcat(ln, buf, sizeof ln); 608 } 609 610 strlcat(ln, " ", sizeof ln); 611 for (j = 0; j < jm; j++) { 612 c = cp[i+j]; 613 c = isprint(c) ? c : '.'; 614 buf[0] = c; 615 buf[1] = '\0'; 616 strlcat(ln, buf, sizeof ln); 617 } 618 printf("%s\n", ln); 619 } 620 } 621 622 /* dump the text from the buffer */ 623 void 624 default_print_ascii(const u_char *cp, unsigned int length) 625 { 626 int c, i; 627 628 printf("\n"); 629 for (i = 0; i < length; i++) { 630 c = cp[i]; 631 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 632 putchar(c); 633 else 634 putchar('.'); 635 } 636 } 637 638 /* Like default_print() but data need not be aligned */ 639 void 640 default_print_unaligned(const u_char *cp, u_int length) 641 { 642 u_int i, s; 643 int nshorts; 644 645 if (Xflag) { 646 /* dump the buffer in `emacs-hexl' style */ 647 default_print_hexl(cp, length); 648 } else if (Aflag) { 649 /* dump the text in the buffer */ 650 default_print_ascii(cp, length); 651 } else { 652 /* dump the buffer in old tcpdump style */ 653 nshorts = (u_int) length / sizeof(u_short); 654 i = 0; 655 while (--nshorts >= 0) { 656 if ((i++ % 8) == 0) 657 (void)printf("\n\t\t\t"); 658 s = *cp++; 659 (void)printf(" %02x%02x", s, *cp++); 660 } 661 if (length & 1) { 662 if ((i % 8) == 0) 663 (void)printf("\n\t\t\t"); 664 (void)printf(" %02x", *cp); 665 } 666 } 667 } 668 669 void 670 default_print(const u_char *bp, u_int length) 671 { 672 const u_short *sp; 673 u_int i; 674 int nshorts; 675 676 if (Xflag) { 677 /* dump the buffer in `emacs-hexl' style */ 678 default_print_hexl(bp, length); 679 } else if (Aflag) { 680 /* dump the text in the buffer */ 681 default_print_ascii(bp, length); 682 } else { 683 /* dump the buffer in old tcpdump style */ 684 if ((long)bp & 1) { 685 default_print_unaligned(bp, length); 686 return; 687 } 688 sp = (u_short *)bp; 689 nshorts = (u_int) length / sizeof(u_short); 690 i = 0; 691 while (--nshorts >= 0) { 692 if ((i++ % 8) == 0) 693 (void)printf("\n\t\t\t"); 694 (void)printf(" %04x", ntohs(*sp++)); 695 } 696 if (length & 1) { 697 if ((i % 8) == 0) 698 (void)printf("\n\t\t\t"); 699 (void)printf(" %02x", *(u_char *)sp); 700 } 701 } 702 } 703 704 void 705 set_slave_signals(void) 706 { 707 setsignal(SIGTERM, cleanup); 708 setsignal(SIGINT, cleanup); 709 setsignal(SIGCHLD, gotchld); 710 setsignal(SIGHUP, cleanup); 711 } 712 713 __dead void 714 usage(void) 715 { 716 (void)fprintf(stderr, 717 "Usage: %s [-AadefILlNnOopqStvXx] [-B fildrop] [-c count] [-D direction]\n", 718 program_name); 719 (void)fprintf(stderr, 720 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 721 (void)fprintf(stderr, 722 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 723 exit(1); 724 } 725