The Tcpdump Group git mirrors - tcpdump/blob - print-ip.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 rcsid[] _U_ =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.159 2007-09-14 01:29:28 guy Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <tcpdump-stdinc.h>
  32
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36
  37 #include "addrtoname.h"
  38 #include "interface.h"
  39 #include "extract.h"                    /* must come after interface.h */
  40
  41 #include "ip.h"
  42 #include "ipproto.h"
  43
  44 struct tok ip_option_values[] = {
  45     { IPOPT_EOL, "EOL" },
  46     { IPOPT_NOP, "NOP" },
  47     { IPOPT_TS, "timestamp" },
  48     { IPOPT_SECURITY, "security" },
  49     { IPOPT_RR, "RR" },
  50     { IPOPT_SSRR, "SSRR" },
  51     { IPOPT_LSRR, "LSRR" },
  52     { IPOPT_RA, "RA" },
  53     { IPOPT_RFC1393, "traceroute" },
  54     { 0, NULL }
  55 };
  56
  57 /*
  58  * print the recorded route in an IP RR, LSRR or SSRR option.
  59  */
  60 static void
  61 ip_printroute(register const u_char *cp, u_int length)
  62 {
  63         register u_int ptr;
  64         register u_int len;
  65
  66         if (length < 3) {
  67                 printf(" [bad length %u]", length);
  68                 return;
  69         }
  70         if ((length + 1) & 3)
  71                 printf(" [bad length %u]", length);
  72         ptr = cp[2] - 1;
  73         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
  74                 printf(" [bad ptr %u]", cp[2]);
  75
  76         for (len = 3; len < length; len += 4) {
  77                 printf(" %s", ipaddr_string(&cp[len]));
  78                 if (ptr > len)
  79                         printf(",");
  80         }
  81 }
  82
  83 /*
  84  * If source-routing is present and valid, return the final destination.
  85  * Otherwise, return IP destination.
  86  *
  87  * This is used for UDP and TCP pseudo-header in the checksum
  88  * calculation.
  89  */
  90 u_int32_t
  91 ip_finddst(const struct ip *ip)
  92 {
  93         int length;
  94         int len;
  95         const u_char *cp;
  96         u_int32_t retval;
  97
  98         cp = (const u_char *)(ip + 1);
  99         length = (IP_HL(ip) << 2) - sizeof(struct ip);
 100
 101         for (; length > 0; cp += len, length -= len) {
 102                 int tt;
 103
 104                 TCHECK(*cp);
 105                 tt = *cp;
 106                 if (tt == IPOPT_EOL)
 107                         break;
 108                 else if (tt == IPOPT_NOP)
 109                         len = 1;
 110                 else {
 111                         TCHECK(cp[1]);
 112                         len = cp[1];
 113                         if (len < 2)
 114                                 break;
 115                 }
 116                 TCHECK2(*cp, len);
 117                 switch (tt) {
 118
 119                 case IPOPT_SSRR:
 120                 case IPOPT_LSRR:
 121                         if (len < 7)
 122                                 break;
 123                         memcpy(&retval, cp + len - 4, 4);
 124                         return retval;
 125                 }
 126         }
 127 trunc:
 128         memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
 129         return retval;
 130 }
 131
 132 static void
 133 ip_printts(register const u_char *cp, u_int length)
 134 {
 135         register u_int ptr;
 136         register u_int len;
 137         int hoplen;
 138         const char *type;
 139
 140         if (length < 4) {
 141                 printf("[bad length %u]", length);
 142                 return;
 143         }
 144         printf(" TS{");
 145         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
 146         if ((length - 4) & (hoplen-1))
 147                 printf("[bad length %u]", length);
 148         ptr = cp[2] - 1;
 149         len = 0;
 150         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
 151                 printf("[bad ptr %u]", cp[2]);
 152         switch (cp[3]&0xF) {
 153         case IPOPT_TS_TSONLY:
 154                 printf("TSONLY");
 155                 break;
 156         case IPOPT_TS_TSANDADDR:
 157                 printf("TS+ADDR");
 158                 break;
 159         /*
 160          * prespecified should really be 3, but some ones might send 2
 161          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 162          * have both values, so we have to hard-code it here.
 163          */
 164
 165         case 2:
 166                 printf("PRESPEC2.0");
 167                 break;
 168         case 3:                 /* IPOPT_TS_PRESPEC */
 169                 printf("PRESPEC");
 170                 break;
 171         default:
 172                 printf("[bad ts type %d]", cp[3]&0xF);
 173                 goto done;
 174         }
 175
 176         type = " ";
 177         for (len = 4; len < length; len += hoplen) {
 178                 if (ptr == len)
 179                         type = " ^ ";
 180                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 181                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 182                 type = " ";
 183         }
 184
 185 done:
 186         printf("%s", ptr == len ? " ^ " : "");
 187
 188         if (cp[3]>>4)
 189                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 190         else
 191                 printf("}");
 192 }
 193
 194 /*
 195  * print IP options.
 196  */
 197 static void
 198 ip_optprint(register const u_char *cp, u_int length)
 199 {
 200         register u_int option_len;
 201         const char *sep = "";
 202
 203         for (; length > 0; cp += option_len, length -= option_len) {
 204                 u_int option_code;
 205
 206                 printf("%s", sep);
 207                 sep = ",";
 208
 209                 TCHECK(*cp);
 210                 option_code = *cp;
 211
 212                 printf("%s",
 213                         tok2str(ip_option_values,"unknown %u",option_code));
 214
 215                 if (option_code == IPOPT_NOP ||
 216                     option_code == IPOPT_EOL)
 217                         option_len = 1;
 218
 219                 else {
 220                         TCHECK(cp[1]);
 221                         option_len = cp[1];
 222                         if (option_len < 2) {
 223                                 printf(" [bad length %u]", option_len);
 224                                 return;
 225                         }
 226                 }
 227
 228                 if (option_len > length) {
 229                         printf(" [bad length %u]", option_len);
 230                         return;
 231                 }
 232
 233                 TCHECK2(*cp, option_len);
 234
 235                 switch (option_code) {
 236                 case IPOPT_EOL:
 237                         return;
 238
 239                 case IPOPT_TS:
 240                         ip_printts(cp, option_len);
 241                         break;
 242
 243                 case IPOPT_RR:       /* fall through */
 244                 case IPOPT_SSRR:
 245                 case IPOPT_LSRR:
 246                         ip_printroute(cp, option_len);
 247                         break;
 248
 249                 case IPOPT_RA:
 250                         if (option_len < 4) {
 251                                 printf(" [bad length %u]", option_len);
 252                                 break;
 253                         }
 254                         TCHECK(cp[3]);
 255                         if (EXTRACT_16BITS(&cp[2]) != 0)
 256                             printf(" value %u", EXTRACT_16BITS(&cp[2]));
 257                         break;
 258
 259                 case IPOPT_NOP:       /* nothing to print - fall through */
 260                 case IPOPT_SECURITY:
 261                 default:
 262                         break;
 263                 }
 264         }
 265         return;
 266
 267 trunc:
 268         printf("[|ip]");
 269 }
 270
 271 #define IP_RES 0x8000
 272
 273 static struct tok ip_frag_values[] = {
 274         { IP_MF,        "+" },
 275         { IP_DF,        "DF" },
 276         { IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
 277         { 0,            NULL }
 278 };
 279
 280 struct ip_print_demux_state {
 281         const struct ip *ip;
 282         const u_char *cp;
 283         u_int   len, off;
 284         u_char  nh;
 285         int     advance;
 286 };
 287
 288 static void
 289 ip_print_demux(netdissect_options *ndo,
 290                struct ip_print_demux_state *ipds)
 291 {
 292         struct protoent *proto;
 293         struct cksum_vec vec[1];
 294
 295 again:
 296         switch (ipds->nh) {
 297
 298         case IPPROTO_AH:
 299                 ipds->nh = *ipds->cp;
 300                 ipds->advance = ah_print(ipds->cp);
 301                 if (ipds->advance <= 0)
 302                         break;
 303                 ipds->cp += ipds->advance;
 304                 ipds->len -= ipds->advance;
 305                 goto again;
 306
 307         case IPPROTO_ESP:
 308         {
 309                 int enh, padlen;
 310                 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
 311                                     (const u_char *)ipds->ip,
 312                                     &enh, &padlen);
 313                 if (ipds->advance <= 0)
 314                         break;
 315                 ipds->cp += ipds->advance;
 316                 ipds->len -= ipds->advance + padlen;
 317                 ipds->nh = enh & 0xff;
 318                 goto again;
 319         }
 320
 321         case IPPROTO_IPCOMP:
 322         {
 323                 int enh;
 324                 ipds->advance = ipcomp_print(ipds->cp, &enh);
 325                 if (ipds->advance <= 0)
 326                         break;
 327                 ipds->cp += ipds->advance;
 328                 ipds->len -= ipds->advance;
 329                 ipds->nh = enh & 0xff;
 330                 goto again;
 331         }
 332
 333         case IPPROTO_SCTP:
 334                 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 335                 break;
 336
 337         case IPPROTO_DCCP:
 338                 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 339                 break;
 340
 341         case IPPROTO_TCP:
 342                 /* pass on the MF bit plus the offset to detect fragments */
 343                 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 344                           ipds->off & (IP_MF|IP_OFFMASK));
 345                 break;
 346
 347         case IPPROTO_UDP:
 348                 /* pass on the MF bit plus the offset to detect fragments */
 349                 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 350                           ipds->off & (IP_MF|IP_OFFMASK));
 351                 break;
 352
 353         case IPPROTO_ICMP:
 354                 /* pass on the MF bit plus the offset to detect fragments */
 355                 icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 356                            ipds->off & (IP_MF|IP_OFFMASK));
 357                 break;
 358
 359         case IPPROTO_PIGP:
 360                 /*
 361                  * XXX - the current IANA protocol number assignments
 362                  * page lists 9 as "any private interior gateway
 363                  * (used by Cisco for their IGRP)" and 88 as
 364                  * "EIGRP" from Cisco.
 365                  *
 366                  * Recent BSD <netinet/in.h> headers define
 367                  * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
 368                  * We define IP_PROTO_PIGP as 9 and
 369                  * IP_PROTO_EIGRP as 88; those names better
 370                  * match was the current protocol number
 371                  * assignments say.
 372                  */
 373                 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 374                 break;
 375
 376         case IPPROTO_EIGRP:
 377                 eigrp_print(ipds->cp, ipds->len);
 378                 break;
 379
 380         case IPPROTO_ND:
 381                 ND_PRINT((ndo, " nd %d", ipds->len));
 382                 break;
 383
 384         case IPPROTO_EGP:
 385                 egp_print(ipds->cp, ipds->len);
 386                 break;
 387
 388         case IPPROTO_OSPF:
 389                 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 390                 break;
 391
 392         case IPPROTO_IGMP:
 393                 igmp_print(ipds->cp, ipds->len);
 394                 break;
 395
 396         case IPPROTO_IPV4:
 397                 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 398                 ip_print(ndo, ipds->cp, ipds->len);
 399                 if (! vflag) {
 400                         ND_PRINT((ndo, " (ipip-proto-4)"));
 401                         return;
 402                 }
 403                 break;
 404
 405 #ifdef INET6
 406         case IPPROTO_IPV6:
 407                 /* ip6-in-ip encapsulation */
 408                 ip6_print(ndo, ipds->cp, ipds->len);
 409                 break;
 410 #endif /*INET6*/
 411
 412         case IPPROTO_RSVP:
 413                 rsvp_print(ipds->cp, ipds->len);
 414                 break;
 415
 416         case IPPROTO_GRE:
 417                 /* do it */
 418                 gre_print(ipds->cp, ipds->len);
 419                 break;
 420
 421         case IPPROTO_MOBILE:
 422                 mobile_print(ipds->cp, ipds->len);
 423                 break;
 424
 425         case IPPROTO_PIM:
 426                 vec[0].ptr = ipds->cp;
 427                 vec[0].len = ipds->len;
 428                 pim_print(ipds->cp, ipds->len, in_cksum(vec, 1));
 429                 break;
 430
 431         case IPPROTO_VRRP:
 432                 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
 433                 break;
 434
 435         case IPPROTO_PGM:
 436                 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 437                 break;
 438
 439         default:
 440                 if ((proto = getprotobynumber(ipds->nh)) != NULL)
 441                         ND_PRINT((ndo, " %s", proto->p_name));
 442                 else
 443                         ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
 444                 ND_PRINT((ndo, " %d", ipds->len));
 445                 break;
 446         }
 447 }
 448
 449 void
 450 ip_print_inner(netdissect_options *ndo,
 451                const u_char *bp,
 452                u_int length, u_int nh,
 453                const u_char *bp2)
 454 {
 455         struct ip_print_demux_state  ipd;
 456
 457         ipd.ip = (const struct ip *)bp2;
 458         ipd.cp = bp;
 459         ipd.len  = length;
 460         ipd.off  = 0;
 461         ipd.nh   = nh;
 462         ipd.advance = 0;
 463
 464         ip_print_demux(ndo, &ipd);
 465 }
 466
 467
 468 /*
 469  * print an IP datagram.
 470  */
 471 void
 472 ip_print(netdissect_options *ndo,
 473          const u_char *bp,
 474          u_int length)
 475 {
 476         struct ip_print_demux_state  ipd;
 477         struct ip_print_demux_state *ipds=&ipd;
 478         const u_char *ipend;
 479         u_int hlen;
 480         struct cksum_vec vec[1];
 481         u_int16_t sum, ip_sum;
 482         struct protoent *proto;
 483
 484         ipds->ip = (const struct ip *)bp;
 485         if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
 486             printf("IP%u ", IP_V(ipds->ip));
 487             if (IP_V(ipds->ip) == 6)
 488                 printf(", wrong link-layer encapsulation");
 489         }
 490         else if (!eflag)
 491             printf("IP ");
 492
 493         if ((u_char *)(ipds->ip + 1) > ndo->ndo_snapend) {
 494                 printf("[|ip]");
 495                 return;
 496         }
 497         if (length < sizeof (struct ip)) {
 498                 (void)printf("truncated-ip %u", length);
 499                 return;
 500         }
 501         hlen = IP_HL(ipds->ip) * 4;
 502         if (hlen < sizeof (struct ip)) {
 503                 (void)printf("bad-hlen %u", hlen);
 504                 return;
 505         }
 506
 507         ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
 508         if (length < ipds->len)
 509                 (void)printf("truncated-ip - %u bytes missing! ",
 510                         ipds->len - length);
 511         if (ipds->len < hlen) {
 512 #ifdef GUESS_TSO
 513             if (ipds->len) {
 514                 (void)printf("bad-len %u", ipds->len);
 515                 return;
 516             }
 517             else {
 518                 /* we guess that it is a TSO send */
 519                 ipds->len = length;
 520             }
 521 #else
 522             (void)printf("bad-len %u", ipds->len);
 523             return;
 524 #endif /* GUESS_TSO */
 525         }
 526
 527         /*
 528          * Cut off the snapshot length to the end of the IP payload.
 529          */
 530         ipend = bp + ipds->len;
 531         if (ipend < ndo->ndo_snapend)
 532                 ndo->ndo_snapend = ipend;
 533
 534         ipds->len -= hlen;
 535
 536         ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
 537
 538         if (vflag) {
 539             (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
 540             /* ECN bits */
 541             if (ipds->ip->ip_tos & 0x03) {
 542                 switch (ipds->ip->ip_tos & 0x03) {
 543                 case 1:
 544                     (void)printf(",ECT(1)");
 545                     break;
 546                 case 2:
 547                     (void)printf(",ECT(0)");
 548                     break;
 549                 case 3:
 550                     (void)printf(",CE");
 551                 }
 552             }
 553
 554             if (ipds->ip->ip_ttl >= 1)
 555                 (void)printf(", ttl %u", ipds->ip->ip_ttl);
 556
 557             /*
 558              * for the firewall guys, print id, offset.
 559              * On all but the last stick a "+" in the flags portion.
 560              * For unfragmented datagrams, note the don't fragment flag.
 561              */
 562
 563             (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
 564                          EXTRACT_16BITS(&ipds->ip->ip_id),
 565                          (ipds->off & 0x1fff) * 8,
 566                          bittok2str(ip_frag_values, "none", ipds->off&0xe000),
 567                          tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
 568                          ipds->ip->ip_p);
 569
 570             (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
 571
 572             if ((hlen - sizeof(struct ip)) > 0) {
 573                 printf(", options (");
 574                 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
 575                 printf(")");
 576             }
 577
 578             if (!Kflag && (u_char *)ipds->ip + hlen <= ndo->ndo_snapend) {
 579                 vec[0].ptr = (const u_int8_t *)(void *)ipds->ip;
 580                 vec[0].len = hlen;
 581                 sum = in_cksum(vec, 1);
 582                 if (sum != 0) {
 583                     ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
 584                     (void)printf(", bad cksum %x (->%x)!", ip_sum,
 585                              in_cksum_shouldbe(ip_sum, sum));
 586                 }
 587             }
 588
 589             printf(")\n    ");
 590         }
 591
 592         /*
 593          * If this is fragment zero, hand it to the next higher
 594          * level protocol.
 595          */
 596         if ((ipds->off & 0x1fff) == 0) {
 597                 ipds->cp = (const u_char *)ipds->ip + hlen;
 598                 ipds->nh = ipds->ip->ip_p;
 599
 600                 if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
 601                     ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
 602                         (void)printf("%s > %s: ",
 603                                      ipaddr_string(&ipds->ip->ip_src),
 604                                      ipaddr_string(&ipds->ip->ip_dst));
 605                 }
 606                 ip_print_demux(ndo, ipds);
 607         } else {
 608             /* Ultra quiet now means that all this stuff should be suppressed */
 609             if (qflag > 1) return;
 610
 611             /*
 612              * if this isn't the first frag, we're missing the
 613              * next level protocol header.  print the ip addr
 614              * and the protocol.
 615              */
 616             if (ipds->off & 0x1fff) {
 617                 (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
 618                              ipaddr_string(&ipds->ip->ip_dst));
 619                 if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
 620                     (void)printf(" %s", proto->p_name);
 621                 else
 622                     (void)printf(" ip-proto-%d", ipds->ip->ip_p);
 623             }
 624         }
 625 }
 626
 627 void
 628 ipN_print(register const u_char *bp, register u_int length)
 629 {
 630         struct ip *ip, hdr;
 631
 632         ip = (struct ip *)bp;
 633         if (length < 4) {
 634                 (void)printf("truncated-ip %d", length);
 635                 return;
 636         }
 637         memcpy (&hdr, (char *)ip, 4);
 638         switch (IP_V(&hdr)) {
 639         case 4:
 640                 ip_print (gndo, bp, length);
 641                 return;
 642 #ifdef INET6
 643         case 6:
 644                 ip6_print (gndo, bp, length);
 645                 return;
 646 #endif
 647         default:
 648                 (void)printf("unknown ip %d", IP_V(&hdr));
 649                 return;
 650         }
 651 }
 652
 653 /*
 654  * Local Variables:
 655  * c-style: whitesmith
 656  * c-basic-offset: 8
 657  * End:
 658  */
 659
 660