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 1.149.2.4 2005-11-13 11:51:52 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     { 0, NULL }
  54 };
  55
  56 /*
  57  * print the recorded route in an IP RR, LSRR or SSRR option.
  58  */
  59 static void
  60 ip_printroute(register const u_char *cp, u_int length)
  61 {
  62         register u_int ptr;
  63         register u_int len;
  64
  65         if (length < 3) {
  66                 printf(" [bad length %u]", length);
  67                 return;
  68         }
  69         if ((length + 1) & 3)
  70                 printf(" [bad length %u]", length);
  71         ptr = cp[2] - 1;
  72         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
  73                 printf(" [bad ptr %u]", cp[2]);
  74
  75         for (len = 3; len < length; len += 4) {
  76                 printf("%s", ipaddr_string(&cp[len]));
  77                 if (ptr > len)
  78                     printf (", ");
  79         }
  80 }
  81
  82 /*
  83  * If source-routing is present and valid, return the final destination.
  84  * Otherwise, return IP destination.
  85  *
  86  * This is used for UDP and TCP pseudo-header in the checksum
  87  * calculation.
  88  */
  89 u_int32_t
  90 ip_finddst(const struct ip *ip)
  91 {
  92         int length;
  93         int len;
  94         const u_char *cp;
  95         u_int32_t retval;
  96
  97         cp = (const u_char *)(ip + 1);
  98         length = (IP_HL(ip) << 2) - sizeof(struct ip);
  99
 100         for (; length > 0; cp += len, length -= len) {
 101                 int tt;
 102
 103                 TCHECK(*cp);
 104                 tt = *cp;
 105                 if (tt == IPOPT_EOL)
 106                         break;
 107                 else if (tt == IPOPT_NOP)
 108                         len = 1;
 109                 else {
 110                         TCHECK(cp[1]);
 111                         len = cp[1];
 112                         if (len < 2)
 113                                 break;
 114                 }
 115                 TCHECK2(*cp, len);
 116                 switch (tt) {
 117
 118                 case IPOPT_SSRR:
 119                 case IPOPT_LSRR:
 120                         if (len < 7)
 121                                 break;
 122                         memcpy(&retval, cp + len - 4, 4);
 123                         return retval;
 124                 }
 125         }
 126 trunc:
 127         memcpy(&retval, &ip->ip_dst.s_addr, sizeof(u_int32_t));
 128         return retval;
 129 }
 130
 131 static void
 132 ip_printts(register const u_char *cp, u_int length)
 133 {
 134         register u_int ptr;
 135         register u_int len;
 136         int hoplen;
 137         const char *type;
 138
 139         if (length < 4) {
 140                 printf("[bad length %d]", length);
 141                 return;
 142         }
 143         printf(" TS{");
 144         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
 145         if ((length - 4) & (hoplen-1))
 146                 printf("[bad length %d]", length);
 147         ptr = cp[2] - 1;
 148         len = 0;
 149         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
 150                 printf("[bad ptr %d]", cp[2]);
 151         switch (cp[3]&0xF) {
 152         case IPOPT_TS_TSONLY:
 153                 printf("TSONLY");
 154                 break;
 155         case IPOPT_TS_TSANDADDR:
 156                 printf("TS+ADDR");
 157                 break;
 158         /*
 159          * prespecified should really be 3, but some ones might send 2
 160          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 161          * have both values, so we have to hard-code it here.
 162          */
 163
 164         case 2:
 165                 printf("PRESPEC2.0");
 166                 break;
 167         case 3:                 /* IPOPT_TS_PRESPEC */
 168                 printf("PRESPEC");
 169                 break;
 170         default:
 171                 printf("[bad ts type %d]", cp[3]&0xF);
 172                 goto done;
 173         }
 174
 175         type = " ";
 176         for (len = 4; len < length; len += hoplen) {
 177                 if (ptr == len)
 178                         type = " ^ ";
 179                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 180                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 181                 type = " ";
 182         }
 183
 184 done:
 185         printf("%s", ptr == len ? " ^ " : "");
 186
 187         if (cp[3]>>4)
 188                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 189         else
 190                 printf("}");
 191 }
 192
 193 /*
 194  * print IP options.
 195  */
 196 static void
 197 ip_optprint(register const u_char *cp, u_int length)
 198 {
 199         register u_int option_len;
 200
 201         for (; length > 0; cp += option_len, length -= option_len) {
 202                 u_int option_code;
 203
 204                 TCHECK(*cp);
 205                 option_code = *cp;
 206
 207                 if (option_code == IPOPT_NOP ||
 208                     option_code == IPOPT_EOL)
 209                         option_len = 1;
 210
 211                 else {
 212                         TCHECK(cp[1]);
 213                         option_len = cp[1];
 214                 }
 215
 216                 printf("%s (%u) len %u",
 217                        tok2str(ip_option_values,"unknown",option_code),
 218                        option_code,
 219                        option_len);
 220
 221                 if (option_len < 2)
 222                         return;
 223
 224                 TCHECK2(*cp, option_len);
 225
 226                 switch (option_code) {
 227                 case IPOPT_EOL:
 228                         return;
 229
 230                 case IPOPT_TS:
 231                         ip_printts(cp, option_len);
 232                         break;
 233
 234                 case IPOPT_RR:       /* fall through */
 235                 case IPOPT_SSRR:
 236                 case IPOPT_LSRR:
 237                         ip_printroute( cp, option_len);
 238                         break;
 239
 240                 case IPOPT_RA:
 241                         TCHECK(cp[3]);
 242                         if (EXTRACT_16BITS(&cp[2]) != 0)
 243                             printf("value %u", EXTRACT_16BITS(&cp[2]));
 244                         break;
 245
 246                 case IPOPT_NOP:       /* nothing to print - fall through */
 247                 case IPOPT_SECURITY:
 248                 default:
 249                         break;
 250                 }
 251         }
 252         return;
 253
 254 trunc:
 255         printf("[|ip]");
 256 }
 257
 258 /*
 259  * compute an IP header checksum.
 260  * don't modifiy the packet.
 261  */
 262 u_short
 263 in_cksum(const u_short *addr, register u_int len, int csum)
 264 {
 265         int nleft = len;
 266         const u_short *w = addr;
 267         u_short answer;
 268         int sum = csum;
 269
 270         /*
 271          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 272          *  we add sequential 16 bit words to it, and at the end, fold
 273          *  back all the carry bits from the top 16 bits into the lower
 274          *  16 bits.
 275          */
 276         while (nleft > 1)  {
 277                 sum += *w++;
 278                 nleft -= 2;
 279         }
 280         if (nleft == 1)
 281                 sum += htons(*(u_char *)w<<8);
 282
 283         /*
 284          * add back carry outs from top 16 bits to low 16 bits
 285          */
 286         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 287         sum += (sum >> 16);                     /* add carry */
 288         answer = ~sum;                          /* truncate to 16 bits */
 289         return (answer);
 290 }
 291
 292 /*
 293  * Given the host-byte-order value of the checksum field in a packet
 294  * header, and the network-byte-order computed checksum of the data
 295  * that the checksum covers (including the checksum itself), compute
 296  * what the checksum field *should* have been.
 297  */
 298 u_int16_t
 299 in_cksum_shouldbe(u_int16_t sum, u_int16_t computed_sum)
 300 {
 301         u_int32_t shouldbe;
 302
 303         /*
 304          * The value that should have gone into the checksum field
 305          * is the negative of the value gotten by summing up everything
 306          * *but* the checksum field.
 307          *
 308          * We can compute that by subtracting the value of the checksum
 309          * field from the sum of all the data in the packet, and then
 310          * computing the negative of that value.
 311          *
 312          * "sum" is the value of the checksum field, and "computed_sum"
 313          * is the negative of the sum of all the data in the packets,
 314          * so that's -(-computed_sum - sum), or (sum + computed_sum).
 315          *
 316          * All the arithmetic in question is one's complement, so the
 317          * addition must include an end-around carry; we do this by
 318          * doing the arithmetic in 32 bits (with no sign-extension),
 319          * and then adding the upper 16 bits of the sum, which contain
 320          * the carry, to the lower 16 bits of the sum, and then do it
 321          * again in case *that* sum produced a carry.
 322          *
 323          * As RFC 1071 notes, the checksum can be computed without
 324          * byte-swapping the 16-bit words; summing 16-bit words
 325          * on a big-endian machine gives a big-endian checksum, which
 326          * can be directly stuffed into the big-endian checksum fields
 327          * in protocol headers, and summing words on a little-endian
 328          * machine gives a little-endian checksum, which must be
 329          * byte-swapped before being stuffed into a big-endian checksum
 330          * field.
 331          *
 332          * "computed_sum" is a network-byte-order value, so we must put
 333          * it in host byte order before subtracting it from the
 334          * host-byte-order value from the header; the adjusted checksum
 335          * will be in host byte order, which is what we'll return.
 336          */
 337         shouldbe = sum;
 338         shouldbe += ntohs(computed_sum);
 339         shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
 340         shouldbe = (shouldbe & 0xFFFF) + (shouldbe >> 16);
 341         return shouldbe;
 342 }
 343
 344 #ifndef IP_MF
 345 #define IP_MF 0x2000
 346 #endif /* IP_MF */
 347 #ifndef IP_DF
 348 #define IP_DF 0x4000
 349 #endif /* IP_DF */
 350 #define IP_RES 0x8000
 351
 352 static struct tok ip_frag_values[] = {
 353         { IP_MF,        "+" },
 354         { IP_DF,        "DF" },
 355         { IP_RES,       "rsvd" }, /* The RFC3514 evil ;-) bit */
 356         { 0,            NULL }
 357 };
 358
 359 struct ip_print_demux_state {
 360         const struct ip *ip;
 361         const u_char *cp;
 362         u_int   len, off;
 363         u_char  nh;
 364         int     advance;
 365 };
 366
 367 static void
 368 ip_print_demux(netdissect_options *ndo,
 369                struct ip_print_demux_state *ipds)
 370 {
 371         struct protoent *proto;
 372
 373 again:
 374         switch (ipds->nh) {
 375
 376         case IPPROTO_AH:
 377                 ipds->nh = *ipds->cp;
 378                 ipds->advance = ah_print(ipds->cp);
 379                 if (ipds->advance <= 0)
 380                         break;
 381                 ipds->cp += ipds->advance;
 382                 ipds->len -= ipds->advance;
 383                 goto again;
 384
 385         case IPPROTO_ESP:
 386         {
 387                 int enh, padlen;
 388                 ipds->advance = esp_print(ndo, ipds->cp, ipds->len,
 389                                     (const u_char *)ipds->ip,
 390                                     &enh, &padlen);
 391                 if (ipds->advance <= 0)
 392                         break;
 393                 ipds->cp += ipds->advance;
 394                 ipds->len -= ipds->advance + padlen;
 395                 ipds->nh = enh & 0xff;
 396                 goto again;
 397         }
 398
 399         case IPPROTO_IPCOMP:
 400         {
 401                 int enh;
 402                 ipds->advance = ipcomp_print(ipds->cp, &enh);
 403                 if (ipds->advance <= 0)
 404                         break;
 405                 ipds->cp += ipds->advance;
 406                 ipds->len -= ipds->advance;
 407                 ipds->nh = enh & 0xff;
 408                 goto again;
 409         }
 410
 411         case IPPROTO_SCTP:
 412                 sctp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 413                 break;
 414
 415         case IPPROTO_DCCP:
 416                 dccp_print(ipds->cp, (const u_char *)ipds->ip, ipds->len);
 417                 break;
 418
 419         case IPPROTO_TCP:
 420                 /* pass on the MF bit plus the offset to detect fragments */
 421                 tcp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 422                           ipds->off & (IP_MF|IP_OFFMASK));
 423                 break;
 424
 425         case IPPROTO_UDP:
 426                 /* pass on the MF bit plus the offset to detect fragments */
 427                 udp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 428                           ipds->off & (IP_MF|IP_OFFMASK));
 429                 break;
 430
 431         case IPPROTO_ICMP:
 432                 /* pass on the MF bit plus the offset to detect fragments */
 433                 icmp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip,
 434                            ipds->off & (IP_MF|IP_OFFMASK));
 435                 break;
 436
 437         case IPPROTO_PIGP:
 438                 /*
 439                  * XXX - the current IANA protocol number assignments
 440                  * page lists 9 as "any private interior gateway
 441                  * (used by Cisco for their IGRP)" and 88 as
 442                  * "EIGRP" from Cisco.
 443                  *
 444                  * Recent BSD <netinet/in.h> headers define
 445                  * IP_PROTO_PIGP as 9 and IP_PROTO_IGRP as 88.
 446                  * We define IP_PROTO_PIGP as 9 and
 447                  * IP_PROTO_EIGRP as 88; those names better
 448                  * match was the current protocol number
 449                  * assignments say.
 450                  */
 451                 igrp_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 452                 break;
 453
 454         case IPPROTO_EIGRP:
 455                 eigrp_print(ipds->cp, ipds->len);
 456                 break;
 457
 458         case IPPROTO_ND:
 459                 ND_PRINT((ndo, " nd %d", ipds->len));
 460                 break;
 461
 462         case IPPROTO_EGP:
 463                 egp_print(ipds->cp, ipds->len);
 464                 break;
 465
 466         case IPPROTO_OSPF:
 467                 ospf_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 468                 break;
 469
 470         case IPPROTO_IGMP:
 471                 igmp_print(ipds->cp, ipds->len);
 472                 break;
 473
 474         case IPPROTO_IPV4:
 475                 /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 476                 ip_print(gndo, ipds->cp, ipds->len);
 477                 if (! vflag) {
 478                         ND_PRINT((ndo, " (ipip-proto-4)"));
 479                         return;
 480                 }
 481                 break;
 482
 483 #ifdef INET6
 484         case IPPROTO_IPV6:
 485                 /* ip6-in-ip encapsulation */
 486                 ip6_print(ipds->cp, ipds->len);
 487                 break;
 488 #endif /*INET6*/
 489
 490         case IPPROTO_RSVP:
 491                 rsvp_print(ipds->cp, ipds->len);
 492                 break;
 493
 494         case IPPROTO_GRE:
 495                 /* do it */
 496                 gre_print(ipds->cp, ipds->len);
 497                 break;
 498
 499         case IPPROTO_MOBILE:
 500                 mobile_print(ipds->cp, ipds->len);
 501                 break;
 502
 503         case IPPROTO_PIM:
 504                 pim_print(ipds->cp,  ipds->len);
 505                 break;
 506
 507         case IPPROTO_VRRP:
 508                 vrrp_print(ipds->cp, ipds->len, ipds->ip->ip_ttl);
 509                 break;
 510
 511         case IPPROTO_PGM:
 512                 pgm_print(ipds->cp, ipds->len, (const u_char *)ipds->ip);
 513                 break;
 514
 515         default:
 516                 if ((proto = getprotobynumber(ipds->nh)) != NULL)
 517                         ND_PRINT((ndo, " %s", proto->p_name));
 518                 else
 519                         ND_PRINT((ndo, " ip-proto-%d", ipds->nh));
 520                 ND_PRINT((ndo, " %d", ipds->len));
 521                 break;
 522         }
 523 }
 524
 525 void
 526 ip_print_inner(netdissect_options *ndo,
 527                const u_char *bp,
 528                u_int length, u_int nh,
 529                const u_char *bp2)
 530 {
 531         struct ip_print_demux_state  ipd;
 532
 533         ipd.ip = (const struct ip *)bp2;
 534         ipd.cp = bp;
 535         ipd.len  = length;
 536         ipd.off  = 0;
 537         ipd.nh   = nh;
 538         ipd.advance = 0;
 539
 540         ip_print_demux(ndo, &ipd);
 541 }
 542
 543
 544 /*
 545  * print an IP datagram.
 546  */
 547 void
 548 ip_print(netdissect_options *ndo,
 549          const u_char *bp,
 550          u_int length)
 551 {
 552         struct ip_print_demux_state  ipd;
 553         struct ip_print_demux_state *ipds=&ipd;
 554         const u_char *ipend;
 555         u_int hlen;
 556         u_int16_t sum, ip_sum;
 557         struct protoent *proto;
 558
 559         ipds->ip = (const struct ip *)bp;
 560         if (IP_V(ipds->ip) != 4) { /* print version if != 4 */
 561             printf("IP%u ", IP_V(ipds->ip));
 562             if (IP_V(ipds->ip) == 6)
 563                 printf(", wrong link-layer encapsulation");
 564         }
 565         else if (!eflag)
 566             printf("IP ");
 567
 568         if ((u_char *)(ipds->ip + 1) > snapend) {
 569                 printf("[|ip]");
 570                 return;
 571         }
 572         if (length < sizeof (struct ip)) {
 573                 (void)printf("truncated-ip %u", length);
 574                 return;
 575         }
 576         hlen = IP_HL(ipds->ip) * 4;
 577         if (hlen < sizeof (struct ip)) {
 578                 (void)printf("bad-hlen %u", hlen);
 579                 return;
 580         }
 581
 582         ipds->len = EXTRACT_16BITS(&ipds->ip->ip_len);
 583         if (length < ipds->len)
 584                 (void)printf("truncated-ip - %u bytes missing! ",
 585                         ipds->len - length);
 586         if (ipds->len < hlen) {
 587 #ifdef GUESS_TSO
 588             if (ipds->len) {
 589                 (void)printf("bad-len %u", ipds->len);
 590                 return;
 591             }
 592             else {
 593                 /* we guess that it is a TSO send */
 594                 ipds->len = length;
 595             }
 596 #else
 597             (void)printf("bad-len %u", ipds->len);
 598             return;
 599 #endif /* GUESS_TSO */
 600         }
 601
 602         /*
 603          * Cut off the snapshot length to the end of the IP payload.
 604          */
 605         ipend = bp + ipds->len;
 606         if (ipend < snapend)
 607                 snapend = ipend;
 608
 609         ipds->len -= hlen;
 610
 611         ipds->off = EXTRACT_16BITS(&ipds->ip->ip_off);
 612
 613         if (vflag) {
 614             (void)printf("(tos 0x%x", (int)ipds->ip->ip_tos);
 615             /* ECN bits */
 616             if (ipds->ip->ip_tos & 0x03) {
 617                 switch (ipds->ip->ip_tos & 0x03) {
 618                 case 1:
 619                     (void)printf(",ECT(1)");
 620                     break;
 621                 case 2:
 622                     (void)printf(",ECT(0)");
 623                     break;
 624                 case 3:
 625                     (void)printf(",CE");
 626                 }
 627             }
 628
 629             if (ipds->ip->ip_ttl >= 1)
 630                 (void)printf(", ttl %3u", ipds->ip->ip_ttl);
 631
 632             /*
 633              * for the firewall guys, print id, offset.
 634              * On all but the last stick a "+" in the flags portion.
 635              * For unfragmented datagrams, note the don't fragment flag.
 636              */
 637
 638             (void)printf(", id %u, offset %u, flags [%s], proto: %s (%u)",
 639                          EXTRACT_16BITS(&ipds->ip->ip_id),
 640                          (ipds->off & 0x1fff) * 8,
 641                          bittok2str(ip_frag_values, "none", ipds->off&0xe000 ),
 642                          tok2str(ipproto_values,"unknown",ipds->ip->ip_p),
 643                          ipds->ip->ip_p);
 644
 645             (void)printf(", length: %u", EXTRACT_16BITS(&ipds->ip->ip_len));
 646
 647             if ((hlen - sizeof(struct ip)) > 0) {
 648                 printf(", options ( ");
 649                 ip_optprint((u_char *)(ipds->ip + 1), hlen - sizeof(struct ip));
 650                 printf(" )");
 651             }
 652
 653             if ((u_char *)ipds->ip + hlen <= snapend) {
 654                 sum = in_cksum((const u_short *)ipds->ip, hlen, 0);
 655                 if (sum != 0) {
 656                     ip_sum = EXTRACT_16BITS(&ipds->ip->ip_sum);
 657                     (void)printf(", bad cksum %x (->%x)!", ip_sum,
 658                              in_cksum_shouldbe(ip_sum, sum));
 659                 }
 660             }
 661
 662             printf(") ");
 663         }
 664
 665         /*
 666          * If this is fragment zero, hand it to the next higher
 667          * level protocol.
 668          */
 669         if ((ipds->off & 0x1fff) == 0) {
 670                 ipds->cp = (const u_char *)ipds->ip + hlen;
 671                 ipds->nh = ipds->ip->ip_p;
 672
 673                 if (ipds->nh != IPPROTO_TCP && ipds->nh != IPPROTO_UDP &&
 674                     ipds->nh != IPPROTO_SCTP && ipds->nh != IPPROTO_DCCP) {
 675                         (void)printf("%s > %s: ",
 676                                      ipaddr_string(&ipds->ip->ip_src),
 677                                      ipaddr_string(&ipds->ip->ip_dst));
 678                 }
 679                 ip_print_demux(ndo, ipds);
 680         } else {
 681             /* Ultra quiet now means that all this stuff should be suppressed */
 682             if (qflag > 1) return;
 683
 684             /*
 685              * if this isn't the first frag, we're missing the
 686              * next level protocol header.  print the ip addr
 687              * and the protocol.
 688              */
 689             if (ipds->off & 0x1fff) {
 690                 (void)printf("%s > %s:", ipaddr_string(&ipds->ip->ip_src),
 691                              ipaddr_string(&ipds->ip->ip_dst));
 692                 if ((proto = getprotobynumber(ipds->ip->ip_p)) != NULL)
 693                     (void)printf(" %s", proto->p_name);
 694                 else
 695                     (void)printf(" ip-proto-%d", ipds->ip->ip_p);
 696             }
 697         }
 698 }
 699
 700 void
 701 ipN_print(register const u_char *bp, register u_int length)
 702 {
 703         struct ip *ip, hdr;
 704
 705         ip = (struct ip *)bp;
 706         if (length < 4) {
 707                 (void)printf("truncated-ip %d", length);
 708                 return;
 709         }
 710         memcpy (&hdr, (char *)ip, 4);
 711         switch (IP_V(&hdr)) {
 712         case 4:
 713                 ip_print (gndo, bp, length);
 714                 return;
 715 #ifdef INET6
 716         case 6:
 717                 ip6_print (bp, length);
 718                 return;
 719 #endif
 720         default:
 721                 (void)printf("unknown ip %d", IP_V(&hdr));
 722                 return;
 723         }
 724 }
 725
 726 /*
 727  * Local Variables:
 728  * c-style: whitesmith
 729  * c-basic-offset: 8
 730  * End:
 731  */
 732
 733