1 /* $OpenBSD: print-ip.c,v 1.39 2014/08/14 12:44:44 mpi 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 #include <sys/param.h> 25 #include <sys/time.h> 26 #include <sys/socket.h> 27 28 #include <netinet/in.h> 29 #include <netinet/ip.h> 30 #include <netinet/ip_var.h> 31 #include <netinet/udp.h> 32 #include <netinet/udp_var.h> 33 #include <netinet/tcp.h> 34 35 #include <inttypes.h> 36 #include <stdio.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <unistd.h> 40 41 #include "addrtoname.h" 42 #include "interface.h" 43 #include "extract.h" /* must come after interface.h */ 44 45 /* Compatibility */ 46 #ifndef IPPROTO_ND 47 #define IPPROTO_ND 77 48 #endif 49 50 #ifndef IN_CLASSD 51 #define IN_CLASSD(i) (((int32_t)(i) & 0xf0000000) == 0xe0000000) 52 #endif 53 54 /* Definitions required for ECN 55 for use if the OS running tcpdump does not have ECN */ 56 #ifndef IPTOS_ECT 57 #define IPTOS_ECT 0x02 /* ECN Capable Transport in IP header*/ 58 #endif 59 #ifndef IPTOS_CE 60 #define IPTOS_CE 0x01 /* ECN Cong. Experienced in IP header*/ 61 #endif 62 63 /* (following from ipmulti/mrouted/prune.h) */ 64 65 /* 66 * The packet format for a traceroute request. 67 */ 68 struct tr_query { 69 u_int tr_src; /* traceroute source */ 70 u_int tr_dst; /* traceroute destination */ 71 u_int tr_raddr; /* traceroute response address */ 72 #if BYTE_ORDER == BIG_ENDIAN 73 struct { 74 u_int ttl : 8; /* traceroute response ttl */ 75 u_int qid : 24; /* traceroute query id */ 76 } q; 77 #else 78 struct { 79 u_int qid : 24; /* traceroute query id */ 80 u_int ttl : 8; /* traceroute response ttl */ 81 } q; 82 #endif 83 }; 84 85 #define tr_rttl q.ttl 86 #define tr_qid q.qid 87 88 /* 89 * Traceroute response format. A traceroute response has a tr_query at the 90 * beginning, followed by one tr_resp for each hop taken. 91 */ 92 struct tr_resp { 93 u_int tr_qarr; /* query arrival time */ 94 u_int tr_inaddr; /* incoming interface address */ 95 u_int tr_outaddr; /* outgoing interface address */ 96 u_int tr_rmtaddr; /* parent address in source tree */ 97 u_int tr_vifin; /* input packet count on interface */ 98 u_int tr_vifout; /* output packet count on interface */ 99 u_int tr_pktcnt; /* total incoming packets for src-grp */ 100 u_char tr_rproto; /* routing proto deployed on router */ 101 u_char tr_fttl; /* ttl required to forward on outvif */ 102 u_char tr_smask; /* subnet mask for src addr */ 103 u_char tr_rflags; /* forwarding error codes */ 104 }; 105 106 /* defs within mtrace */ 107 #define TR_QUERY 1 108 #define TR_RESP 2 109 110 /* fields for tr_rflags (forwarding error codes) */ 111 #define TR_NO_ERR 0 112 #define TR_WRONG_IF 1 113 #define TR_PRUNED 2 114 #define TR_OPRUNED 3 115 #define TR_SCOPED 4 116 #define TR_NO_RTE 5 117 #define TR_NO_FWD 7 118 #define TR_NO_SPACE 0x81 119 #define TR_OLD_ROUTER 0x82 120 121 /* fields for tr_rproto (routing protocol) */ 122 #define TR_PROTO_DVMRP 1 123 #define TR_PROTO_MOSPF 2 124 #define TR_PROTO_PIM 3 125 #define TR_PROTO_CBT 4 126 127 static void print_mtrace(register const u_char *bp, register u_int len) 128 { 129 register struct tr_query *tr = (struct tr_query *)(bp + 8); 130 131 printf("mtrace %d: %s to %s reply-to %s", tr->tr_qid, 132 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst), 133 ipaddr_string(&tr->tr_raddr)); 134 if (IN_CLASSD(ntohl(tr->tr_raddr))) 135 printf(" with-ttl %d", tr->tr_rttl); 136 } 137 138 static void print_mresp(register const u_char *bp, register u_int len) 139 { 140 register struct tr_query *tr = (struct tr_query *)(bp + 8); 141 142 printf("mresp %d: %s to %s reply-to %s", tr->tr_qid, 143 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst), 144 ipaddr_string(&tr->tr_raddr)); 145 if (IN_CLASSD(ntohl(tr->tr_raddr))) 146 printf(" with-ttl %d", tr->tr_rttl); 147 } 148 149 static void 150 igmp_print(register const u_char *bp, register u_int len, 151 register const u_char *bp2) 152 { 153 register const struct ip *ip; 154 155 ip = (const struct ip *)bp2; 156 (void)printf("%s > %s: ", 157 ipaddr_string(&ip->ip_src), 158 ipaddr_string(&ip->ip_dst)); 159 160 TCHECK2(bp[0], 8); 161 switch (bp[0]) { 162 case 0x11: 163 (void)printf("igmp query"); 164 if (*(int *)&bp[4]) 165 (void)printf(" [gaddr %s]", ipaddr_string(&bp[4])); 166 if (len != 8) 167 (void)printf(" [len %d]", len); 168 break; 169 case 0x12: 170 (void)printf("igmp report %s", ipaddr_string(&bp[4])); 171 if (len != 8) 172 (void)printf(" [len %d]", len); 173 break; 174 case 0x16: 175 (void)printf("igmp nreport %s", ipaddr_string(&bp[4])); 176 break; 177 case 0x17: 178 (void)printf("igmp leave %s", ipaddr_string(&bp[4])); 179 break; 180 case 0x13: 181 (void)printf("igmp dvmrp"); 182 if (len < 8) 183 (void)printf(" [len %d]", len); 184 else 185 dvmrp_print(bp, len); 186 break; 187 case 0x14: 188 (void)printf("igmp pim"); 189 pim_print(bp, len); 190 break; 191 case 0x1e: 192 print_mresp(bp, len); 193 break; 194 case 0x1f: 195 print_mtrace(bp, len); 196 break; 197 default: 198 (void)printf("igmp-%d", bp[0] & 0xf); 199 break; 200 } 201 if ((bp[0] >> 4) != 1) 202 (void)printf(" [v%d]", bp[0] >> 4); 203 204 TCHECK2(bp[0], len); 205 if (vflag) { 206 /* Check the IGMP checksum */ 207 u_int32_t sum = 0; 208 int count; 209 const u_short *sp = (u_short *)bp; 210 211 for (count = len / 2; --count >= 0; ) 212 sum += *sp++; 213 if (len & 1) 214 sum += ntohs(*(u_char *) sp << 8); 215 while (sum >> 16) 216 sum = (sum & 0xffff) + (sum >> 16); 217 sum = 0xffff & ~sum; 218 if (sum != 0) 219 printf(" bad igmp cksum %x!", EXTRACT_16BITS(&bp[2])); 220 } 221 return; 222 trunc: 223 fputs("[|igmp]", stdout); 224 } 225 226 /* 227 * print the recorded route in an IP RR, LSRR or SSRR option. 228 */ 229 static void 230 ip_printroute(const char *type, register const u_char *cp, u_int length) 231 { 232 register u_int ptr = cp[2] - 1; 233 register u_int len; 234 235 printf(" %s{", type); 236 if ((length + 1) & 3) 237 printf(" [bad length %d]", length); 238 if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1) 239 printf(" [bad ptr %d]", cp[2]); 240 241 type = ""; 242 for (len = 3; len < length; len += 4) { 243 if (ptr == len) 244 type = "#"; 245 printf("%s%s", type, ipaddr_string(&cp[len])); 246 type = " "; 247 } 248 printf("%s}", ptr == len? "#" : ""); 249 } 250 251 /* 252 * print IP options. 253 */ 254 static void 255 ip_optprint(register const u_char *cp, u_int length) 256 { 257 register u_int len; 258 int tt; 259 260 for (; length > 0; cp += len, length -= len) { 261 TCHECK(cp[1]); 262 tt = *cp; 263 len = (tt == IPOPT_NOP || tt == IPOPT_EOL) ? 1 : cp[1]; 264 if (len <= 0) { 265 printf("[|ip op len %d]", len); 266 return; 267 } 268 if (&cp[1] >= snapend || cp + len > snapend) { 269 printf("[|ip]"); 270 return; 271 } 272 switch (tt) { 273 274 case IPOPT_EOL: 275 printf(" EOL"); 276 if (length > 1) 277 printf("-%d", length - 1); 278 return; 279 280 case IPOPT_NOP: 281 printf(" NOP"); 282 break; 283 284 case IPOPT_TS: 285 printf(" TS{%d}", len); 286 break; 287 288 case IPOPT_SECURITY: 289 printf(" SECURITY{%d}", len); 290 break; 291 292 case IPOPT_RR: 293 printf(" RR{%d}=", len); 294 ip_printroute("RR", cp, len); 295 break; 296 297 case IPOPT_SSRR: 298 ip_printroute("SSRR", cp, len); 299 break; 300 301 case IPOPT_LSRR: 302 ip_printroute("LSRR", cp, len); 303 break; 304 305 default: 306 printf(" IPOPT-%d{%d}", cp[0], len); 307 break; 308 } 309 } 310 return; 311 312 trunc: 313 printf("[|ip]"); 314 } 315 316 /* 317 * compute an IP header checksum. 318 * don't modifiy the packet. 319 */ 320 u_short 321 in_cksum(const u_short *addr, register int len, int csum) 322 { 323 int nleft = len; 324 const u_short *w = addr; 325 u_short answer; 326 int sum = csum; 327 328 /* 329 * Our algorithm is simple, using a 32 bit accumulator (sum), 330 * we add sequential 16 bit words to it, and at the end, fold 331 * back all the carry bits from the top 16 bits into the lower 332 * 16 bits. 333 */ 334 while (nleft > 1) { 335 sum += *w++; 336 nleft -= 2; 337 } 338 if (nleft == 1) 339 sum += htons(*(u_char *)w<<8); 340 341 /* 342 * add back carry outs from top 16 bits to low 16 bits 343 */ 344 sum = (sum >> 16) + (sum & 0xffff); /* add hi 16 to low 16 */ 345 sum += (sum >> 16); /* add carry */ 346 answer = ~sum; /* truncate to 16 bits */ 347 return (answer); 348 } 349 350 /* 351 * print an IP datagram. 352 */ 353 void 354 ip_print(register const u_char *bp, register u_int length) 355 { 356 register const struct ip *ip; 357 register u_int hlen, len, off; 358 register const u_char *cp; 359 360 ip = (const struct ip *)bp; 361 /* 362 * If the IP header is not aligned, copy into abuf. 363 * This will never happen with BPF. It does happen with raw packet 364 * dumps from -r. 365 */ 366 if ((intptr_t)ip & (sizeof(long)-1)) { 367 static u_char *abuf = NULL; 368 static int didwarn = 0; 369 int clen = snapend - bp; 370 371 if (clen > snaplen) 372 clen = snaplen; 373 if (abuf == NULL) { 374 abuf = (u_char *)malloc(snaplen); 375 if (abuf == NULL) 376 error("ip_print: malloc"); 377 } 378 memmove((char *)abuf, (char *)ip, min(length, clen)); 379 snapend = abuf + clen; 380 packetp = abuf; 381 ip = (struct ip *)abuf; 382 /* We really want libpcap to give us aligned packets */ 383 if (!didwarn) { 384 warning("compensating for unaligned libpcap packets"); 385 ++didwarn; 386 } 387 } 388 389 TCHECK(*ip); 390 if (ip->ip_v != IPVERSION) { 391 (void)printf("bad-ip-version %u", ip->ip_v); 392 return; 393 } 394 395 len = ntohs(ip->ip_len); 396 if (length < len) { 397 (void)printf("truncated-ip - %d bytes missing!", 398 len - length); 399 len = length; 400 } 401 402 hlen = ip->ip_hl * 4; 403 if (hlen < sizeof(struct ip) || hlen > len) { 404 (void)printf("bad-hlen %d", hlen); 405 return; 406 } 407 408 len -= hlen; 409 410 /* 411 * If this is fragment zero, hand it to the next higher 412 * level protocol. 413 */ 414 off = ntohs(ip->ip_off); 415 if ((off & 0x1fff) == 0) { 416 cp = (const u_char *)ip + hlen; 417 switch (ip->ip_p) { 418 419 case IPPROTO_TCP: 420 tcp_print(cp, len, (const u_char *)ip); 421 break; 422 423 case IPPROTO_UDP: 424 udp_print(cp, len, (const u_char *)ip); 425 break; 426 427 case IPPROTO_ICMP: 428 icmp_print(cp, len, (const u_char *)ip); 429 break; 430 431 #ifndef IPPROTO_IGRP 432 #define IPPROTO_IGRP 9 433 #endif 434 case IPPROTO_IGRP: 435 igrp_print(cp, len, (const u_char *)ip); 436 break; 437 438 case IPPROTO_ND: 439 (void)printf("%s > %s:", ipaddr_string(&ip->ip_src), 440 ipaddr_string(&ip->ip_dst)); 441 (void)printf(" nd %d", len); 442 break; 443 444 #ifndef IPPROTO_OSPF 445 #define IPPROTO_OSPF 89 446 #endif 447 case IPPROTO_OSPF: 448 ospf_print(cp, len, (const u_char *)ip); 449 break; 450 451 #ifndef IPPROTO_IGMP 452 #define IPPROTO_IGMP 2 453 #endif 454 case IPPROTO_IGMP: 455 igmp_print(cp, len, (const u_char *)ip); 456 break; 457 458 #ifndef IPPROTO_IPIP 459 #define IPPROTO_IPIP 4 460 #endif 461 case IPPROTO_IPIP: 462 /* ip-in-ip encapsulation */ 463 if (vflag) 464 (void)printf("%s > %s: ", 465 ipaddr_string(&ip->ip_src), 466 ipaddr_string(&ip->ip_dst)); 467 ip_print(cp, len); 468 if (! vflag) { 469 printf(" (encap)"); 470 return; 471 } 472 break; 473 474 #ifdef INET6 475 #ifndef IPPROTO_IPV6 476 #define IPPROTO_IPV6 477 #endif 478 case IPPROTO_IPV6: 479 /* ip6-in-ip encapsulation */ 480 if (vflag) 481 (void)printf("%s > %s: ", 482 ipaddr_string(&ip->ip_src), 483 ipaddr_string(&ip->ip_dst)); 484 ip6_print(cp, len); 485 if (! vflag) { 486 printf(" (encap)"); 487 return; 488 } 489 break; 490 #endif /*INET6*/ 491 492 #ifndef IPPROTO_GRE 493 #define IPPROTO_GRE 47 494 #endif 495 case IPPROTO_GRE: 496 if (vflag) 497 (void)printf("gre %s > %s: ", 498 ipaddr_string(&ip->ip_src), 499 ipaddr_string(&ip->ip_dst)); 500 /* do it */ 501 gre_print(cp, len); 502 if (! vflag) { 503 printf(" (gre encap)"); 504 return; 505 } 506 break; 507 508 #ifndef IPPROTO_ESP 509 #define IPPROTO_ESP 50 510 #endif 511 case IPPROTO_ESP: 512 esp_print(cp, len, (const u_char *)ip); 513 break; 514 515 #ifndef IPPROTO_AH 516 #define IPPROTO_AH 51 517 #endif 518 case IPPROTO_AH: 519 ah_print(cp, len, (const u_char *)ip); 520 break; 521 522 #ifndef IPPROTO_MOBILE 523 #define IPPROTO_MOBILE 55 524 #endif 525 case IPPROTO_MOBILE: 526 if (vflag) 527 (void)printf("mobile %s > %s: ", 528 ipaddr_string(&ip->ip_src), 529 ipaddr_string(&ip->ip_dst)); 530 mobile_print(cp, len); 531 if (! vflag) { 532 printf(" (mobile encap)"); 533 return; 534 } 535 break; 536 537 #ifndef IPPROTO_ETHERIP 538 #define IPPROTO_ETHERIP 97 539 #endif 540 case IPPROTO_ETHERIP: 541 etherip_print(cp, snapend - cp, len, 542 (const u_char *)ip); 543 break; 544 545 #ifndef IPPROTO_IPCOMP 546 #define IPPROTO_IPCOMP 108 547 #endif 548 case IPPROTO_IPCOMP: 549 ipcomp_print(cp, len, (const u_char *)ip); 550 break; 551 552 #ifndef IPPROTO_CARP 553 #define IPPROTO_CARP 112 554 #endif 555 case IPPROTO_CARP: 556 if (packettype == PT_VRRP) { 557 if (vflag) 558 (void)printf("vrrp %s > %s: ", 559 ipaddr_string(&ip->ip_src), 560 ipaddr_string(&ip->ip_dst)); 561 vrrp_print(cp, len, ip->ip_ttl); 562 } else { 563 if (vflag) 564 (void)printf("carp %s > %s: ", 565 ipaddr_string(&ip->ip_src), 566 ipaddr_string(&ip->ip_dst)); 567 carp_print(cp, len, ip->ip_ttl); 568 } 569 break; 570 571 #ifndef IPPROTO_PFSYNC 572 #define IPPROTO_PFSYNC 240 573 #endif 574 case IPPROTO_PFSYNC: 575 pfsync_ip_print(cp, 576 (int)(snapend - (u_char *)ip) - hlen, 577 (const u_char *)ip); 578 break; 579 580 default: 581 (void)printf("%s > %s:", ipaddr_string(&ip->ip_src), 582 ipaddr_string(&ip->ip_dst)); 583 (void)printf(" ip-proto-%d %d", ip->ip_p, len); 584 break; 585 } 586 } 587 /* 588 * for fragmented datagrams, print id:size@offset. On all 589 * but the last stick a "+". For unfragmented datagrams, note 590 * the don't fragment flag. 591 */ 592 if (off & 0x3fff) { 593 /* 594 * if this isn't the first frag, we're missing the 595 * next level protocol header. print the ip addr. 596 */ 597 if (off & 0x1fff) 598 (void)printf("%s > %s:", ipaddr_string(&ip->ip_src), 599 ipaddr_string(&ip->ip_dst)); 600 (void)printf(" (frag %d:%d@%d%s)", ntohs(ip->ip_id), len, 601 (off & 0x1fff) * 8, 602 (off & IP_MF)? "+" : ""); 603 } 604 if (off & IP_DF) 605 (void)printf(" (DF)"); 606 607 if (ip->ip_tos) { 608 (void)printf(" [tos 0x%x", (int)ip->ip_tos); 609 if (ip->ip_tos & (IPTOS_CE|IPTOS_ECT)) { 610 (void)printf(" ("); 611 if (ip->ip_tos & IPTOS_ECT) { 612 /* ECN-capable transport */ 613 putchar('E'); 614 } 615 if (ip->ip_tos & IPTOS_CE) { 616 /* _C_ongestion experienced (ECN) */ 617 putchar('C'); 618 } 619 (void)printf(")"); 620 } 621 (void)printf("]"); 622 } 623 624 if (ip->ip_ttl <= 1) 625 (void)printf(" [ttl %d]", (int)ip->ip_ttl); 626 627 if (vflag) { 628 char *sep = ""; 629 630 printf(" ("); 631 if (ip->ip_ttl > 1) { 632 (void)printf("%sttl %d", sep, (int)ip->ip_ttl); 633 sep = ", "; 634 } 635 if ((off & 0x3fff) == 0) { 636 (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id)); 637 sep = ", "; 638 } 639 (void)printf("%slen %u", sep, ntohs(ip->ip_len)); 640 sep = ", "; 641 if ((u_char *)ip + hlen <= snapend) { 642 u_int16_t sum, ip_sum; 643 sum = in_cksum((const u_short *)ip, hlen, 0); 644 if (sum != 0) { 645 ip_sum = EXTRACT_16BITS(&ip->ip_sum); 646 (void)printf("%sbad ip cksum %x! -> %x", sep, ip_sum, 647 in_cksum_shouldbe(ip_sum, sum)); 648 sep = ", "; 649 } 650 } 651 if (hlen > sizeof(struct ip)) { 652 hlen -= sizeof(struct ip); 653 (void)printf("%soptlen=%d", sep, hlen); 654 ip_optprint((u_char *)(ip + 1), hlen); 655 } 656 printf(")"); 657 } 658 return; 659 660 trunc: 661 printf("[|ip]"); 662 } 663