1 /* $OpenBSD: tcpdump.c,v 1.88 2018/11/08 14:06:09 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 { ppp_hdlc_if_print, DLT_PPP_SERIAL }, 119 { fddi_if_print, DLT_FDDI }, 120 { null_if_print, DLT_NULL }, 121 { raw_if_print, DLT_RAW }, 122 { atm_if_print, DLT_ATM_RFC1483 }, 123 { loop_if_print, DLT_LOOP }, 124 { enc_if_print, DLT_ENC }, 125 { pflog_if_print, DLT_PFLOG }, 126 { pfsync_if_print, DLT_PFSYNC }, 127 { ppp_ether_if_print, DLT_PPP_ETHER }, 128 { ieee802_11_if_print, DLT_IEEE802_11 }, 129 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 130 { ofp_if_print, DLT_OPENFLOW }, 131 { usbpcap_if_print, DLT_USBPCAP }, 132 { NULL, 0 }, 133 }; 134 135 static pcap_handler 136 lookup_printer(int type) 137 { 138 struct printer *p; 139 140 for (p = printers; p->f; ++p) { 141 if (type == p->type) 142 return p->f; 143 } 144 145 error("unknown data link type 0x%x", type); 146 /* NOTREACHED */ 147 } 148 149 static int 150 init_pfosfp(void) 151 { 152 pf_osfp_initialize(); 153 if (pfctl_file_fingerprints(-1, 154 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 155 return 1; 156 return 0; 157 } 158 159 static pcap_t *pd; 160 161 /* Multiple DLT support */ 162 void pcap_list_linktypes(pcap_t *); 163 void pcap_print_linktype(u_int); 164 165 void 166 pcap_print_linktype(u_int dlt) 167 { 168 const char *name; 169 170 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 171 fprintf(stderr, "%s\n", name); 172 else 173 fprintf(stderr, "<unknown: %u>\n", dlt); 174 } 175 176 void 177 pcap_list_linktypes(pcap_t *p) 178 { 179 int fd = p->fd; 180 u_int n; 181 182 #define MAXDLT 100 183 184 u_int dltlist[MAXDLT]; 185 struct bpf_dltlist dl = {MAXDLT, dltlist}; 186 187 if (fd < 0) 188 error("Invalid bpf descriptor"); 189 190 if (ioctl(fd, BIOCGDLTLIST, &dl) < 0) 191 err(1, "BIOCGDLTLIST"); 192 193 if (dl.bfl_len > MAXDLT) 194 error("Invalid number of linktypes: %u", dl.bfl_len); 195 196 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 197 dl.bfl_len == 1 ? "" : "s"); 198 199 for (n = 0; n < dl.bfl_len; n++) { 200 fprintf(stderr, "\t"); 201 pcap_print_linktype(dltlist[n]); 202 } 203 } 204 205 int 206 main(int argc, char **argv) 207 { 208 int cnt = -1, op, i; 209 bpf_u_int32 localnet, netmask; 210 char *cp, *infile = NULL, *RFileName = NULL; 211 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 212 pcap_handler printer; 213 struct bpf_program *fcode; 214 u_char *pcap_userdata; 215 u_int dirfilt = 0, dlt = (u_int) -1; 216 const char *errstr; 217 218 if ((cp = strrchr(argv[0], '/')) != NULL) 219 program_name = cp + 1; 220 else 221 program_name = argv[0]; 222 223 /* '-P' used internally, exec privileged portion */ 224 if (argc >= 2 && strcmp("-P", argv[1]) == 0) 225 priv_exec(argc, argv); 226 227 if (priv_init(argc, argv)) 228 error("Failed to setup privsep"); 229 230 /* state: STATE_INIT */ 231 232 opterr = 0; 233 while ((op = getopt(argc, argv, 234 "Aac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 235 switch (op) { 236 237 case 'A': 238 xflag = 1; 239 Aflag = 1; 240 break; 241 242 case 'a': 243 aflag = 1; 244 break; 245 246 case 'c': 247 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 248 if (errstr) 249 error("invalid packet count %s: %s", 250 optarg, errstr); 251 break; 252 253 case 'D': 254 if (strcasecmp(optarg, "in") == 0) 255 dirfilt = BPF_DIRECTION_OUT; 256 else if (strcasecmp(optarg, "out") == 0) 257 dirfilt = BPF_DIRECTION_IN; 258 else 259 error("invalid traffic direction %s", optarg); 260 break; 261 262 case 'd': 263 ++dflag; 264 break; 265 case 'e': 266 eflag = 1; 267 break; 268 269 case 'f': 270 fflag = 1; 271 break; 272 273 case 'F': 274 infile = optarg; 275 break; 276 277 case 'i': 278 device = optarg; 279 break; 280 281 case 'I': 282 Iflag = 1; 283 break; 284 285 case 'l': 286 setvbuf(stdout, NULL, _IOLBF, 0); 287 break; 288 case 'L': 289 Lflag = 1; 290 break; 291 case 'n': 292 nflag = 1; 293 break; 294 295 case 'N': 296 Nflag = 1; 297 break; 298 299 case 'O': 300 Oflag = 0; 301 break; 302 303 case 'o': 304 oflag = 1; 305 break; 306 307 case 'p': 308 pflag = 1; 309 break; 310 311 case 'q': 312 qflag = 1; 313 break; 314 315 case 'r': 316 RFileName = optarg; 317 break; 318 319 case 's': 320 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 321 if (errstr) 322 error("invalid snaplen %s: %s", optarg, errstr); 323 break; 324 325 case 'S': 326 Sflag = 1; 327 break; 328 329 case 't': 330 --tflag; 331 break; 332 333 case 'T': 334 if (strcasecmp(optarg, "vat") == 0) 335 packettype = PT_VAT; 336 else if (strcasecmp(optarg, "wb") == 0) 337 packettype = PT_WB; 338 else if (strcasecmp(optarg, "rpc") == 0) 339 packettype = PT_RPC; 340 else if (strcasecmp(optarg, "rtp") == 0) 341 packettype = PT_RTP; 342 else if (strcasecmp(optarg, "rtcp") == 0) 343 packettype = PT_RTCP; 344 else if (strcasecmp(optarg, "cnfp") == 0) 345 packettype = PT_CNFP; 346 else if (strcasecmp(optarg, "vrrp") == 0) 347 packettype = PT_VRRP; 348 else if (strcasecmp(optarg, "tcp") == 0) 349 packettype = PT_TCP; 350 else if (strcasecmp(optarg, "gre") == 0) 351 packettype = PT_GRE; 352 else if (strcasecmp(optarg, "vxlan") == 0) 353 packettype = PT_VXLAN; 354 else if (strcasecmp(optarg, "mpls") == 0) 355 packettype = PT_MPLS; 356 else if (strcasecmp(optarg, "tftp") == 0) 357 packettype = PT_TFTP; 358 else if (strcasecmp(optarg, "sack") == 0) 359 /* 360 * kept for compatibility; DEFAULT_SNAPLEN 361 * used to be too short to capture SACK. 362 */ 363 ; 364 else 365 error("unknown packet type `%s'", optarg); 366 break; 367 368 case 'v': 369 ++vflag; 370 break; 371 372 case 'w': 373 WFileName = optarg; 374 break; 375 #ifdef YYDEBUG 376 case 'Y': 377 { 378 /* Undocumented flag */ 379 extern int yydebug; 380 yydebug = 1; 381 } 382 break; 383 #endif 384 case 'y': 385 i = pcap_datalink_name_to_val(optarg); 386 if (i < 0) 387 error("invalid data link type: %s", optarg); 388 dlt = (u_int)i; 389 break; 390 391 case 'x': 392 xflag = 1; 393 break; 394 395 case 'X': 396 Xflag = 1; 397 xflag = 1; 398 break; 399 400 case 'E': 401 if (esp_init(optarg) < 0) 402 error("bad esp specification `%s'", optarg); 403 break; 404 405 default: 406 usage(); 407 /* NOTREACHED */ 408 } 409 410 if (snaplen == 0) { 411 switch (dlt) { 412 case DLT_IEEE802_11: 413 snaplen = IEEE802_11_SNAPLEN; 414 break; 415 case DLT_IEEE802_11_RADIO: 416 snaplen = IEEE802_11_RADIO_SNAPLEN; 417 break; 418 default: 419 snaplen = DEFAULT_SNAPLEN; 420 break; 421 } 422 } 423 424 if (aflag && nflag) 425 error("-a and -n options are incompatible"); 426 427 if (RFileName != NULL) { 428 pd = priv_pcap_offline(RFileName, ebuf); 429 if (pd == NULL) 430 error("%s", ebuf); 431 /* state: STATE_BPF */ 432 localnet = 0; 433 netmask = 0; 434 if (fflag != 0) 435 error("-f and -r options are incompatible"); 436 } else { 437 if (device == NULL) { 438 device = pcap_lookupdev(ebuf); 439 if (device == NULL) 440 error("%s", ebuf); 441 } 442 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 443 dlt, dirfilt); 444 if (pd == NULL) 445 error("%s", ebuf); 446 447 /* state: STATE_BPF */ 448 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 449 if (fflag) 450 warning("%s", ebuf); 451 localnet = 0; 452 netmask = 0; 453 } 454 } 455 i = pcap_snapshot(pd); 456 if (snaplen < i) { 457 warning("snaplen raised from %d to %d", snaplen, i); 458 snaplen = i; 459 } 460 461 if (Lflag) { 462 pcap_list_linktypes(pd); 463 exit(0); 464 } 465 466 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 467 /* state: STATE_FILTER */ 468 if (fcode == NULL) 469 error("%s", pcap_geterr(pd)); 470 if (dflag) { 471 bpf_dump(fcode, dflag); 472 exit(0); 473 } 474 if (oflag) 475 oflag = init_pfosfp(); 476 init_addrtoname(localnet, netmask); 477 478 if (WFileName) { 479 pcap_dumper_t *p; 480 481 p = priv_pcap_dump_open(pd, WFileName); 482 /* state: STATE_RUN */ 483 if (p == NULL) 484 error("%s", pcap_geterr(pd)); 485 { 486 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 487 fflush(fp); 488 setvbuf(fp, NULL, _IONBF, 0); 489 } 490 printer = pcap_dump; 491 pcap_userdata = (u_char *)p; 492 } else { 493 printer = lookup_printer(pcap_datalink(pd)); 494 pcap_userdata = NULL; 495 priv_init_done(); 496 /* state: STATE_RUN */ 497 } 498 if (RFileName == NULL) { 499 (void)fprintf(stderr, "%s: listening on %s, link-type ", 500 program_name, device); 501 pcap_print_linktype(pd->linktype); 502 (void)fflush(stderr); 503 } 504 505 if (tflag > 0) 506 thiszone = gmt2local(0); 507 508 if (pledge("stdio", NULL) == -1) 509 err(1, "pledge"); 510 511 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 512 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 513 program_name, pcap_geterr(pd)); 514 exit(1); 515 } 516 pcap_close(pd); 517 exit(0); 518 } 519 520 /* make a clean exit on interrupts */ 521 void 522 cleanup(int signo) 523 { 524 struct pcap_stat stat; 525 sigset_t allsigs; 526 527 sigfillset(&allsigs); 528 sigprocmask(SIG_BLOCK, &allsigs, NULL); 529 530 /* Can't print the summary if reading from a savefile */ 531 dprintf(STDERR_FILENO, "\n"); 532 if (pd != NULL && pcap_file(pd) == NULL) { 533 if (priv_pcap_stats(&stat) < 0) { 534 dprintf(STDERR_FILENO, 535 "pcap_stats: %s\n", pcap_geterr(pd)); 536 } else { 537 dprintf(STDERR_FILENO, 538 "%u packets received by filter\n", stat.ps_recv); 539 dprintf(STDERR_FILENO, 540 "%u packets dropped by kernel\n", stat.ps_drop); 541 } 542 } 543 _exit(0); 544 } 545 546 void 547 gotchld(int signo) 548 { 549 pid_t pid; 550 int status; 551 int save_err = errno; 552 553 do { 554 pid = waitpid(child_pid, &status, WNOHANG); 555 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 556 cleanup(0); 557 } while (pid == -1 && errno == EINTR); 558 559 if (pid == -1) 560 _exit(1); 561 562 errno = save_err; 563 } 564 565 /* dump the buffer in `emacs-hexl' style */ 566 void 567 default_print_hexl(const u_char *cp, unsigned int length) 568 { 569 unsigned int i, j, jm; 570 int c; 571 char ln[128], buf[128]; 572 573 printf("\n"); 574 for (i = 0; i < length; i += 0x10) { 575 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 576 jm = length - i; 577 jm = jm > 16 ? 16 : jm; 578 579 for (j = 0; j < jm; j++) { 580 if ((j % 2) == 1) 581 snprintf(buf, sizeof(buf), "%02x ", 582 (unsigned int)cp[i+j]); 583 else 584 snprintf(buf, sizeof(buf), "%02x", 585 (unsigned int)cp[i+j]); 586 strlcat(ln, buf, sizeof ln); 587 } 588 for (; j < 16; j++) { 589 if ((j % 2) == 1) 590 snprintf(buf, sizeof buf, " "); 591 else 592 snprintf(buf, sizeof buf, " "); 593 strlcat(ln, buf, sizeof ln); 594 } 595 596 strlcat(ln, " ", sizeof ln); 597 for (j = 0; j < jm; j++) { 598 c = cp[i+j]; 599 c = isprint(c) ? c : '.'; 600 buf[0] = c; 601 buf[1] = '\0'; 602 strlcat(ln, buf, sizeof ln); 603 } 604 printf("%s\n", ln); 605 } 606 } 607 608 /* dump the text from the buffer */ 609 void 610 default_print_ascii(const u_char *cp, unsigned int length) 611 { 612 int c, i; 613 614 printf("\n"); 615 for (i = 0; i < length; i++) { 616 c = cp[i]; 617 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 618 putchar(c); 619 else 620 putchar('.'); 621 } 622 } 623 624 /* Like default_print() but data need not be aligned */ 625 void 626 default_print_unaligned(const u_char *cp, u_int length) 627 { 628 u_int i, s; 629 int nshorts; 630 631 if (Xflag) { 632 /* dump the buffer in `emacs-hexl' style */ 633 default_print_hexl(cp, length); 634 } else if (Aflag) { 635 /* dump the text in the buffer */ 636 default_print_ascii(cp, length); 637 } else { 638 /* dump the buffer in old tcpdump style */ 639 nshorts = (u_int) length / sizeof(u_short); 640 i = 0; 641 while (--nshorts >= 0) { 642 if ((i++ % 8) == 0) 643 (void)printf("\n\t\t\t"); 644 s = *cp++; 645 (void)printf(" %02x%02x", s, *cp++); 646 } 647 if (length & 1) { 648 if ((i % 8) == 0) 649 (void)printf("\n\t\t\t"); 650 (void)printf(" %02x", *cp); 651 } 652 } 653 } 654 655 void 656 default_print(const u_char *bp, u_int length) 657 { 658 const u_short *sp; 659 u_int i; 660 int nshorts; 661 662 if (Xflag) { 663 /* dump the buffer in `emacs-hexl' style */ 664 default_print_hexl(bp, length); 665 } else if (Aflag) { 666 /* dump the text in the buffer */ 667 default_print_ascii(bp, length); 668 } else { 669 /* dump the buffer in old tcpdump style */ 670 if ((long)bp & 1) { 671 default_print_unaligned(bp, length); 672 return; 673 } 674 sp = (u_short *)bp; 675 nshorts = (u_int) length / sizeof(u_short); 676 i = 0; 677 while (--nshorts >= 0) { 678 if ((i++ % 8) == 0) 679 (void)printf("\n\t\t\t"); 680 (void)printf(" %04x", ntohs(*sp++)); 681 } 682 if (length & 1) { 683 if ((i % 8) == 0) 684 (void)printf("\n\t\t\t"); 685 (void)printf(" %02x", *(u_char *)sp); 686 } 687 } 688 } 689 690 void 691 set_slave_signals(void) 692 { 693 setsignal(SIGTERM, cleanup); 694 setsignal(SIGINT, cleanup); 695 setsignal(SIGCHLD, gotchld); 696 setsignal(SIGHUP, cleanup); 697 } 698 699 __dead void 700 usage(void) 701 { 702 (void)fprintf(stderr, 703 "Usage: %s [-AadefILlNnOopqStvXx] [-c count] [-D direction]\n", 704 program_name); 705 (void)fprintf(stderr, 706 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 707 (void)fprintf(stderr, 708 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 709 exit(1); 710 } 711