contrib/tcpdump/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 /*
 272  * compute an IP header checksum.
 273  * don't modifiy the packet.
 274  */
 275 u_short
 276 in_cksum(const u_short *addr, register u_int len, int csum)
 277 {
 278         int nleft = len;
 279         const u_short *w = addr;
 280         u_short answer;
 281         int sum = csum;
 282
 283         /*
 284          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 285          *  we add sequential 16 bit words to it, and at the end, fold
 286          *  back all the carry bits from the top 16 bits into the lower
 287          *  16 bits.
 288          */
 289         while (nleft > 1)  {
 290                 sum += *w++;
 291                 nleft -= 2;
 292         }
 293         if (nleft == 1)
 294                 sum += htons(*(u_char *)w<<8);
 295
 296         /*
 297          * add back carry outs from top 16 bits to low 16 bits
 298          */
 299         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 300         sum += (sum >> 16);                     /* add carry */
 301         answer = ~sum;                          /* truncate to 16 bits */
 302         return (answer);
 303 }
 304
 305 /*
 306  * Given the host-byte-order value of the checksum field in a packet
 307  * header, and the network-byte-order computed checksum of the data
 308  * that the checksum covers (including the checksum itself), compute
 309  * what the checksum field *should* have been.
 310  */
 311 u_int16_t
 312 in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
 313 {
 314         u_int32_t shouldbe;
 315
 316         /*
 317          * The value that should have gone into the checksum field
 318          * is the negative of the value gotten by summing up everything
 319          * *but* the checksum field.
 320          *
 321          * We can compute that by subtracting the value of the checksum
 322          * field from the sum of all the data in the packet, and then
 323          * computing the negative of that value.
 324          *
 325          * "sum" is the value of the checksum field, and "computed_sum"
 326          * is the negative of the sum of all the data in the packets,
 327          * so that's -(-computed_sum - sum), or (sum + computed_sum).
 328          *
 329          * All the arithmetic in question is one's complement, so the
 330          * addition must include an end-around carry; we do this by
 331          * doing the arithmetic in 32 bits (with no sign-extension),
 332          * and then adding the upper 16 bits of the sum, which contain
 333          * the carry, to the lower 16 bits of the sum, and then do it
 334          * again in case *that* sum produced a carry.
 335          *
 336          * As RFC 1071 notes, the checksum can be computed without
 337          * byte-swapping the 16-bit words; summing 16-bit words
 338          * on a big-endian machine gives a big-endian checksum, which
 339          * can be directly stuffed into the big-endian checksum fields
 340          * in protocol headers, and summing words on a little-endian
 341          * machine gives a little-endian checksum, which must be
 342          * byte-swapped before being stuffed into a big-endian checksum
 343          * field.
 344          *
 345          * "computed_sum" is a network-byte-order value, so we must put
 346          * it in host byte order before subtracting it from the
 347          * host-byte-order value from the header; the adjusted checksum
 348          * will be in host byte order, which is what we'll return.
 349          */
 350         shouldbe = sum;
 351         shouldbe += ntohs(computed_sum);
 352         shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
 353         shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
 354         return shouldbe;
 355 }
 356
 357 #define IP_RES 0x8000
 358
 359 static struct tok ip_frag_values[] = {
 360         { IP_MF,        "+" },
 361         { IP_DF,        "DF" },
 362         { IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
 363         { 0,            NULL }
 364 };
 365
 366 struct ip_print_demux_state {
 367         const struct ip *ip;
 368         const u_char *cp;
 369         u_int   len, off;
 370         u_char  nh;
 371         int     advance;
 372 };
 373
 374 static void
 375 ip_print_demux(netdissect_options *ndo,
 376                struct ip_print_demux_state *ipds)
 377 {
 378         struct protoent *proto;
 379
 380 again:
 381         switch (ipds->nh) {
 382
 383         case IPPROTO_AH:
 384                 ipds->nh = *ipds->cp;
 385                 ipds->advance = ah_print(ipds->cp);
 386                 if (ipds->advance <= 0)
 387                         break;
 388                 ipds->cp += ipds->advance;
 389                 ipds->len -= ipds->advance;
 390                 goto again;
 391
 392         case IPPROTO_ESP:
 393         {
 394                 int enh, padlen;
 395                 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
 396                                     (const u_char *)ipds->ip,
 397                                     &enh, &padlen);
 398                 if (ipds->advance <= 0)
 399                         break;
 400                 ipds->cp += ipds->advance;
 401                 ipds->len -= ipds->advance + padlen;
 402                 ipds->nh = enh & 0xff;
 403                 goto again;
 404         }
 405
 406         case IPPROTO_IPCOMP:
 407         {
 408                 int enh;
 409                 ipds->advance = ipcomp_print(ipds->cp, &enh);
 410                 if (ipds->advance <= 0)
 411                         break;
 412                 ipds->cp += ipds->advance;
 413                 ipds->len -= ipds->advance;
 414                 ipds->nh = enh & 0xff;
 415                 goto again;
 416         }
 417
 418         case IPPROTO_SCTP:
 419                 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 420                 break;
 421
 422         case IPPROTO_DCCP:
 423                 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 424                 break;
 425
 426         case IPPROTO_TCP:
 427                 /* pass on the MF bit plus the offset to detect fragments */
 428                 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 429                           ipds->off & (IP_MF|IP_OFFMASK));
 430                 break;
 431
 432         case IPPROTO_UDP:
 433                 /* pass on the MF bit plus the offset to detect fragments */
 434                 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 435                           ipds->off & (IP_MF|IP_OFFMASK));
 436                 break;
 437
 438         case IPPROTO_ICMP:
 439                 /* pass on the MF bit plus the offset to detect fragments */
 440                 icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 441                            ipds->off & (IP_MF|IP_OFFMASK));
 442                 break;
 443
 444         case IPPROTO_PIGP:
 445                 /*
 446                  * XXX - the current IANA protocol number assignments
 447                  * page lists 9 as "any private interior gateway
 448                  * (used by Cisco for their IGRP)" and 88 as
 449                  * "EIGRP" from Cisco.
 450                  *
 451                  * Recent BSD <netinet/in.h> headers define
 452                  * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
 453                  * We define IP_PROTO_PIGP as 9 and
 454                  * IP_PROTO_EIGRP as 88; those names better
 455                  * match was the current protocol number
 456                  * assignments say.
 457                  */
 458                 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 459                 break;
 460
 461         case IPPROTO_EIGRP:
 462                 eigrp_print(ipds->cp, ipds->len);
 463                 break;
 464
 465         case IPPROTO_ND:
 466                 ND_PRINT((ndo, " nd %d", ipds->len));
 467                 break;
 468
 469         case IPPROTO_EGP:
 470                 egp_print(ipds->cp, ipds->len);
 471                 break;
 472
 473         case IPPROTO_OSPF:
 474                 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 475                 break;
 476
 477         case IPPROTO_IGMP:
 478                 igmp_print(ipds->cp, ipds->len);
 479                 break;
 480
 481         case IPPROTO_IPV4:
 482                 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 483                 ip_print(gndo, ipds->cp, ipds->len);
 484                 if (! vflag) {
 485                         ND_PRINT((ndo, " (ipip-proto-4)"));
 486                         return;
 487                 }
 488                 break;
 489
 490 #ifdef INET6
 491         case IPPROTO_IPV6:
 492                 /* ip6-in-ip encapsulation */
 493                 ip6_print(ipds->cp, ipds->len);
 494                 break;
 495 #endif /*INET6*/
 496
 497         case IPPROTO_RSVP:
 498                 rsvp_print(ipds->cp, ipds->len);
 499                 break;
 500
 501         case IPPROTO_GRE:
 502                 /* do it */
 503                 gre_print(ipds->cp, ipds->len);
 504                 break;
 505
 506         case IPPROTO_MOBILE:
 507                 mobile_print(ipds->cp, ipds->len);
 508                 break;
 509
 510         case IPPROTO_PIM:
 511                 pim_print(ipds->cp,  ipds->len);
 512                 break;
 513
 514         case IPPROTO_VRRP:
 515                 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
 516                 break;
 517
 518         case IPPROTO_PGM:
 519                 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 520                 break;
 521
 522         default:
 523                 if ((proto = getprotobynumber(ipds->nh)) != NULL)
 524                         ND_PRINT((ndo, " %s", proto->p_name));
 525                 else
 526                         ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
 527                 ND_PRINT((ndo, " %d", ipds->len));
 528                 break;
 529         }
 530 }
 531
 532 void
 533 ip_print_inner(netdissect_options *ndo,
 534                const u_char *bp,
 535                u_int length, u_int nh,
 536                const u_char *bp2)
 537 {
 538         struct ip_print_demux_state  ipd;
 539
 540         ipd.ip = (const struct ip *)bp2;
 541         ipd.cp = bp;
 542         ipd.len  = length;
 543         ipd.off  = 0;
 544         ipd.nh   = nh;
 545         ipd.advance = 0;
 546
 547         ip_print_demux(ndo, &ipd);
 548 }
 549
 550
 551 /*
 552  * print an IP datagram.
 553  */
 554 void
 555 ip_print(netdissect_options *ndo,
 556          const u_char *bp,
 557          u_int length)
 558 {
 559         struct ip_print_demux_state  ipd;
 560         struct ip_print_demux_state *ipds=&ipd;
 561         const u_char *ipend;
 562         u_int hlen;
 563         u_int16_t sum, ip_sum;
 564         struct protoent *proto;
 565
 566         ipds->ip = (const struct ip *)bp;
 567         if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
 568             printf("IP%u ", IP_V(ipds->ip));
 569             if (IP_V(ipds->ip) == 6)
 570                 printf(", wrong link-layer encapsulation");
 571         }
 572         else if (!eflag)
 573             printf("IP ");
 574
 575         if ((u_char *)(ipds->ip + 1) > snapend) {
 576                 printf("[|ip]");
 577                 return;
 578         }
 579         if (length < sizeof (struct ip)) {
 580                 (void)printf("truncated-ip %u", length);
 581                 return;
 582         }
 583         hlen = IP_HL(ipds->ip) * 4;
 584         if (hlen < sizeof (struct ip)) {
 585                 (void)printf("bad-hlen %u", hlen);
 586                 return;
 587         }
 588
 589         ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
 590         if (length < ipds->len)
 591                 (void)printf("truncated-ip - %u bytes missing! ",
 592                         ipds->len - length);
 593         if (ipds->len < hlen) {
 594 #ifdef GUESS_TSO
 595             if (ipds->len) {
 596                 (void)printf("bad-len %u", ipds->len);
 597                 return;
 598             }
 599             else {
 600                 /* we guess that it is a TSO send */
 601                 ipds->len = length;
 602             }
 603 #else
 604             (void)printf("bad-len %u", ipds->len);
 605             return;
 606 #endif /* GUESS_TSO */
 607         }
 608
 609         /*
 610          * Cut off the snapshot length to the end of the IP payload.
 611          */
 612         ipend = bp + ipds->len;
 613         if (ipend < snapend)
 614                 snapend = ipend;
 615
 616         ipds->len -= hlen;
 617
 618         ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
 619
 620         if (vflag) {
 621             (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
 622             /* ECN bits */
 623             if (ipds->ip->ip_tos & 0x03) {
 624                 switch (ipds->ip->ip_tos & 0x03) {
 625                 case 1:
 626                     (void)printf(",ECT(1)");
 627                     break;
 628                 case 2:
 629                     (void)printf(",ECT(0)");
 630                     break;
 631                 case 3:
 632                     (void)printf(",CE");
 633                 }
 634             }
 635
 636             if (ipds->ip->ip_ttl >= 1)
 637                 (void)printf(", ttl %u", ipds->ip->ip_ttl);
 638
 639             /*
 640              * for the firewall guys, print id, offset.
 641              * On all but the last stick a "+" in the flags portion.
 642              * For unfragmented datagrams, note the don't fragment flag.
 643              */
 644
 645             (void)printf(", id %u, offset %u, flags [%s], proto %s (%u)",
 646                          EXTRACT_16BITS(&ipds->ip->ip_id),
 647                          (ipds->off & 0x1fff) * 8,
 648                          bittok2str(ip_frag_values, "none", ipds->off&0xe000),
 649                          tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
 650                          ipds->ip->ip_p);
 651
 652             (void)printf(", length %u", EXTRACT_16BITS(&ipds->ip->ip_len));
 653
 654             if ((hlen - sizeof(struct ip)) > 0) {
 655                 printf(", options (");
 656                 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
 657                 printf(")");
 658             }
 659
 660             if ((u_char *)ipds->ip + hlen <= snapend) {
 661                 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
 662                 if (sum != 0) {
 663                     ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
 664                     (void)printf(", bad cksum %x (->%x)!", ip_sum,
 665                              in_cksum_shouldbe(ip_sum, sum));
 666                 }
 667             }
 668
 669             printf(")\n    ");
 670         }
 671
 672         /*
 673          * If this is fragment zero, hand it to the next higher
 674          * level protocol.
 675          */
 676         if ((ipds->off & 0x1fff) == 0) {
 677                 ipds->cp = (const u_char *)ipds->ip + hlen;
 678                 ipds->nh = ipds->ip->ip_p;
 679
 680                 if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
 681                     ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
 682                         (void)printf("%s > %s: ",
 683                                      ipaddr_string(&ipds->ip->ip_src),
 684                                      ipaddr_string(&ipds->ip->ip_dst));
 685                 }
 686                 ip_print_demux(ndo, ipds);
 687         } else {
 688             /* Ultra quiet now means that all this stuff should be suppressed */
 689             if (qflag > 1) return;
 690
 691             /*
 692              * if this isn't the first frag, we're missing the
 693              * next level protocol header.  print the ip addr
 694              * and the protocol.
 695              */
 696             if (ipds->off & 0x1fff) {
 697                 (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
 698                              ipaddr_string(&ipds->ip->ip_dst));
 699                 if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
 700                     (void)printf(" %s", proto->p_name);
 701                 else
 702                     (void)printf(" ip-proto-%d", ipds->ip->ip_p);
 703             }
 704         }
 705 }
 706
 707 void
 708 ipN_print(register const u_char *bp, register u_int length)
 709 {
 710         struct ip *ip, hdr;
 711
 712         ip = (struct ip *)bp;
 713         if (length < 4) {
 714                 (void)printf("truncated-ip %d", length);
 715                 return;
 716         }
 717         memcpy (&hdr, (char *)ip, 4);
 718         switch (IP_V(&hdr)) {
 719         case 4:
 720                 ip_print (gndo, bp, length);
 721                 return;
 722 #ifdef INET6
 723         case 6:
 724                 ip6_print (bp, length);
 725                 return;
 726 #endif
 727         default:
 728                 (void)printf("unknown ip %d", IP_V(&hdr));
 729                 return;
 730         }
 731 }
 732
 733 /*
 734  * Local Variables:
 735  * c-style: whitesmith
 736  * c-basic-offset: 8
 737  * End:
 738  */
 739
 740