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[] =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-ip.c,v 1.86 2000-09-23 08:26:34 guy Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/param.h>
  32 #include <sys/time.h>
  33 #include <sys/socket.h>
  34
  35 #include <netinet/in.h>
  36 #include <netinet/in_systm.h>
  37 #include <netinet/ip.h>
  38 #include <netinet/ip_var.h>
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44
  45 #include "addrtoname.h"
  46 #include "interface.h"
  47 #include "extract.h"                    /* must come after interface.h */
  48
  49 /* Compatibility */
  50 #ifndef IPPROTO_ND
  51 #define IPPROTO_ND      77
  52 #endif
  53
  54 #ifndef IN_CLASSD
  55 #define IN_CLASSD(i) (((int32_t)(i) & 0xf0000000) == 0xe0000000)
  56 #endif
  57
  58 /* (following from ipmulti/mrouted/prune.h) */
  59
  60 /*
  61  * The packet format for a traceroute request.
  62  */
  63 struct tr_query {
  64         u_int  tr_src;                  /* traceroute source */
  65         u_int  tr_dst;                  /* traceroute destination */
  66         u_int  tr_raddr;                /* traceroute response address */
  67         u_int  tr_rttlqid;              /* response ttl and qid */
  68 };
  69
  70 #define TR_GETTTL(x)            (int)(((x) >> 24) & 0xff)
  71 #define TR_GETQID(x)            ((x) & 0x00ffffff)
  72
  73 /*
  74  * Traceroute response format.  A traceroute response has a tr_query at the
  75  * beginning, followed by one tr_resp for each hop taken.
  76  */
  77 struct tr_resp {
  78         u_int tr_qarr;                  /* query arrival time */
  79         u_int tr_inaddr;                /* incoming interface address */
  80         u_int tr_outaddr;               /* outgoing interface address */
  81         u_int tr_rmtaddr;               /* parent address in source tree */
  82         u_int tr_vifin;                 /* input packet count on interface */
  83         u_int tr_vifout;                /* output packet count on interface */
  84         u_int tr_pktcnt;                /* total incoming packets for src-grp */
  85         u_char  tr_rproto;              /* routing proto deployed on router */
  86         u_char  tr_fttl;                /* ttl required to forward on outvif */
  87         u_char  tr_smask;               /* subnet mask for src addr */
  88         u_char  tr_rflags;              /* forwarding error codes */
  89 };
  90
  91 /* defs within mtrace */
  92 #define TR_QUERY 1
  93 #define TR_RESP 2
  94
  95 /* fields for tr_rflags (forwarding error codes) */
  96 #define TR_NO_ERR       0
  97 #define TR_WRONG_IF     1
  98 #define TR_PRUNED       2
  99 #define TR_OPRUNED      3
 100 #define TR_SCOPED       4
 101 #define TR_NO_RTE       5
 102 #define TR_NO_FWD       7
 103 #define TR_NO_SPACE     0x81
 104 #define TR_OLD_ROUTER   0x82
 105
 106 /* fields for tr_rproto (routing protocol) */
 107 #define TR_PROTO_DVMRP  1
 108 #define TR_PROTO_MOSPF  2
 109 #define TR_PROTO_PIM    3
 110 #define TR_PROTO_CBT    4
 111
 112 static void print_mtrace(register const u_char *bp, register u_int len)
 113 {
 114         register struct tr_query *tr = (struct tr_query *)(bp + 8);
 115
 116         printf("mtrace %lu: %s to %s reply-to %s",
 117                 (u_long)TR_GETQID(ntohl(tr->tr_rttlqid)),
 118                 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
 119                 ipaddr_string(&tr->tr_raddr));
 120         if (IN_CLASSD(ntohl(tr->tr_raddr)))
 121                 printf(" with-ttl %d", TR_GETTTL(ntohl(tr->tr_rttlqid)));
 122 }
 123
 124 static void print_mresp(register const u_char *bp, register u_int len)
 125 {
 126         register struct tr_query *tr = (struct tr_query *)(bp + 8);
 127
 128         printf("mresp %lu: %s to %s reply-to %s",
 129                 (u_long)TR_GETQID(ntohl(tr->tr_rttlqid)),
 130                 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
 131                 ipaddr_string(&tr->tr_raddr));
 132         if (IN_CLASSD(ntohl(tr->tr_raddr)))
 133                 printf(" with-ttl %d", TR_GETTTL(ntohl(tr->tr_rttlqid)));
 134 }
 135
 136 static void
 137 igmp_print(register const u_char *bp, register u_int len,
 138            register const u_char *bp2)
 139 {
 140         register const struct ip *ip;
 141
 142         ip = (const struct ip *)bp2;
 143         (void)printf("%s > %s: ",
 144                 ipaddr_string(&ip->ip_src),
 145                 ipaddr_string(&ip->ip_dst));
 146
 147         if (qflag) {
 148                 (void)printf("igmp");
 149                 return;
 150         }
 151
 152         TCHECK2(bp[0], 8);
 153         switch (bp[0]) {
 154         case 0x11:
 155                 (void)printf("igmp query");
 156                 if (EXTRACT_32BITS(&bp[4]))
 157                         (void)printf(" [gaddr %s]", ipaddr_string(&bp[4]));
 158                 if (len != 8)
 159                         (void)printf(" [len %d]", len);
 160                 break;
 161         case 0x12:
 162                 (void)printf("igmp v1 report %s", ipaddr_string(&bp[4]));
 163                 if (len != 8)
 164                         (void)printf(" [len %d]", len);
 165                 break;
 166         case 0x16:
 167                 (void)printf("igmp v2 report %s", ipaddr_string(&bp[4]));
 168                 break;
 169         case 0x17:
 170                 (void)printf("igmp leave %s", ipaddr_string(&bp[4]));
 171                 break;
 172         case 0x13:
 173                 (void)printf("igmp dvmrp");
 174                 if (len < 8)
 175                         (void)printf(" [len %d]", len);
 176                 else
 177                         dvmrp_print(bp, len);
 178                 break;
 179         case 0x14:
 180                 (void)printf("igmp pimv1");
 181                 pimv1_print(bp, len);
 182                 break;
 183         case 0x1e:
 184                 print_mresp(bp, len);
 185                 break;
 186         case 0x1f:
 187                 print_mtrace(bp, len);
 188                 break;
 189         default:
 190                 (void)printf("igmp-%d", bp[0]);
 191                 break;
 192         }
 193
 194         if (vflag && TTEST2(bp[0], len)) {
 195                 /* Check the IGMP checksum */
 196                 if (in_cksum((const u_short*)bp, len, 0))
 197                         printf(" bad igmp cksum %x!", EXTRACT_16BITS(&bp[2]));
 198         }
 199         return;
 200 trunc:
 201         fputs("[|igmp]", stdout);
 202 }
 203
 204 /*
 205  * print the recorded route in an IP RR, LSRR or SSRR option.
 206  */
 207 static void
 208 ip_printroute(const char *type, register const u_char *cp, u_int length)
 209 {
 210         register u_int ptr = cp[2] - 1;
 211         register u_int len;
 212
 213         printf(" %s{", type);
 214         if ((length + 1) & 3)
 215                 printf(" [bad length %d]", length);
 216         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
 217                 printf(" [bad ptr %d]", cp[2]);
 218
 219         type = "";
 220         for (len = 3; len < length; len += 4) {
 221                 if (ptr == len)
 222                         type = "#";
 223                 printf("%s%s", type, ipaddr_string(&cp[len]));
 224                 type = " ";
 225         }
 226         printf("%s}", ptr == len? "#" : "");
 227 }
 228
 229 static void
 230 ip_printts(register const u_char *cp, u_int length)
 231 {
 232         register u_int ptr = cp[2] - 1;
 233         register u_int len = 0;
 234         int hoplen;
 235         char *type;
 236
 237         printf(" TS{");
 238         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
 239         if ((length - 4) & (hoplen-1))
 240                 printf("[bad length %d]", length);
 241         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
 242                 printf("[bad ptr %d]", cp[2]);
 243         switch (cp[3]&0xF) {
 244         case IPOPT_TS_TSONLY:
 245                 printf("TSONLY");
 246                 break;
 247         case IPOPT_TS_TSANDADDR:
 248                 printf("TS+ADDR");
 249                 break;
 250         /*
 251          * prespecified should really be 3, but some ones might send 2
 252          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 253          * have both values, so we have to hard-code it here.
 254          */
 255
 256         case 2:
 257                 printf("PRESPEC2.0");
 258                 break;
 259         case 3:                 /* IPOPT_TS_PRESPEC */
 260                 printf("PRESPEC");
 261                 break;
 262         default:
 263                 printf("[bad ts type %d]", cp[3]&0xF);
 264                 goto done;
 265         }
 266
 267         type = " ";
 268         for (len = 4; len < length; len += hoplen) {
 269                 if (ptr == len)
 270                         type = " ^ ";
 271                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 272                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 273                 type = " ";
 274         }
 275
 276 done:
 277         printf("%s", ptr == len ? " ^ " : "");
 278
 279         if (cp[3]>>4)
 280                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 281         else
 282                 printf("}");
 283 }
 284
 285 /*
 286  * print IP options.
 287  */
 288 static void
 289 ip_optprint(register const u_char *cp, u_int length)
 290 {
 291         register u_int len;
 292
 293         for (; length > 0; cp += len, length -= len) {
 294                 int tt = *cp;
 295
 296                 if (tt == IPOPT_NOP || tt == IPOPT_EOL)
 297                         len = 1;
 298                 else {
 299                         if (&cp[1] >= snapend) {
 300                                 printf("[|ip]");
 301                                 return;
 302                         }
 303                         len = cp[1];
 304                 }
 305                 if (len <= 0) {
 306                         printf("[|ip op len %d]", len);
 307                         return;
 308                 }
 309                 if (&cp[1] >= snapend || cp + len > snapend) {
 310                         printf("[|ip]");
 311                         return;
 312                 }
 313                 switch (tt) {
 314
 315                 case IPOPT_EOL:
 316                         printf(" EOL");
 317                         if (length > 1)
 318                                 printf("-%d", length - 1);
 319                         return;
 320
 321                 case IPOPT_NOP:
 322                         printf(" NOP");
 323                         break;
 324
 325                 case IPOPT_TS:
 326                         ip_printts(cp, len);
 327                         break;
 328
 329 #ifndef IPOPT_SECURITY
 330 #define IPOPT_SECURITY 130
 331 #endif /* IPOPT_SECURITY */
 332                 case IPOPT_SECURITY:
 333                         printf(" SECURITY{%d}", len);
 334                         break;
 335
 336                 case IPOPT_RR:
 337                         ip_printroute("RR", cp, len);
 338                         break;
 339
 340                 case IPOPT_SSRR:
 341                         ip_printroute("SSRR", cp, len);
 342                         break;
 343
 344                 case IPOPT_LSRR:
 345                         ip_printroute("LSRR", cp, len);
 346                         break;
 347
 348 #ifndef IPOPT_RA
 349 #define IPOPT_RA 148            /* router alert */
 350 #endif
 351                 case IPOPT_RA:
 352                         printf(" RA");
 353                         if (len != 4)
 354                                 printf("{%d}", len);
 355                         else if (cp[2] || cp[3])
 356                                 printf("%d.%d", cp[2], cp[3]);
 357                         break;
 358
 359                 default:
 360                         printf(" IPOPT-%d{%d}", cp[0], len);
 361                         break;
 362                 }
 363         }
 364 }
 365
 366 /*
 367  * compute an IP header checksum.
 368  * don't modifiy the packet.
 369  */
 370 u_short
 371 in_cksum(const u_short *addr, register int len, u_short csum)
 372 {
 373         int nleft = len;
 374         const u_short *w = addr;
 375         u_short answer;
 376         int sum = csum;
 377
 378         /*
 379          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 380          *  we add sequential 16 bit words to it, and at the end, fold
 381          *  back all the carry bits from the top 16 bits into the lower
 382          *  16 bits.
 383          */
 384         while (nleft > 1)  {
 385                 sum += *w++;
 386                 nleft -= 2;
 387         }
 388         if (nleft == 1)
 389                 sum += htons(*(u_char *)w<<8);
 390
 391         /*
 392          * add back carry outs from top 16 bits to low 16 bits
 393          */
 394         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 395         sum += (sum >> 16);                     /* add carry */
 396         answer = ~sum;                          /* truncate to 16 bits */
 397         return (answer);
 398 }
 399
 400 /*
 401  * print an IP datagram.
 402  */
 403 void
 404 ip_print(register const u_char *bp, register u_int length)
 405 {
 406         register const struct ip *ip;
 407         register u_int hlen, len, len0, off;
 408         register const u_char *cp;
 409         u_char nh;
 410         int advance;
 411
 412         ip = (const struct ip *)bp;
 413 #ifdef LBL_ALIGN
 414         /*
 415          * If the IP header is not aligned, copy into abuf.
 416          * This will never happen with BPF.  It does happen raw packet
 417          * dumps from -r.
 418          */
 419         if ((long)ip & 3) {
 420                 static u_char *abuf = NULL;
 421                 static int didwarn = 0;
 422
 423                 if (abuf == NULL) {
 424                         abuf = (u_char *)malloc(snaplen);
 425                         if (abuf == NULL)
 426                                 error("ip_print: malloc");
 427                 }
 428                 memcpy((char *)abuf, (char *)ip, min(length, snaplen));
 429                 snapend += abuf - (u_char *)ip;
 430                 packetp = abuf;
 431                 ip = (struct ip *)abuf;
 432                 /* We really want libpcap to give us aligned packets */
 433                 if (!didwarn) {
 434                         warning("compensating for unaligned libpcap packets");
 435                         ++didwarn;
 436                 }
 437         }
 438 #endif
 439         if ((u_char *)(ip + 1) > snapend) {
 440                 printf("[|ip]");
 441                 return;
 442         }
 443         if (length < sizeof (struct ip)) {
 444                 (void)printf("truncated-ip %d", length);
 445                 return;
 446         }
 447         hlen = ip->ip_hl * 4;
 448         if (hlen < sizeof (struct ip)) {
 449                 (void)printf("bad-hlen %d", hlen);
 450                 return;
 451         }
 452
 453         len = ntohs(ip->ip_len);
 454         if (length < len)
 455                 (void)printf("truncated-ip - %d bytes missing!",
 456                         len - length);
 457         len -= hlen;
 458         len0 = len;
 459
 460         /*
 461          * If this is fragment zero, hand it to the next higher
 462          * level protocol.
 463          */
 464         off = ntohs(ip->ip_off);
 465         if ((off & 0x1fff) == 0) {
 466                 cp = (const u_char *)ip + hlen;
 467                 nh = ip->ip_p;
 468
 469                 if (nh != IPPROTO_TCP && nh != IPPROTO_UDP) {
 470                         (void)printf("%s > %s: ", ipaddr_string(&ip->ip_src),
 471                                 ipaddr_string(&ip->ip_dst));
 472                 }
 473 again:
 474                 switch (nh) {
 475
 476 #ifndef IPPROTO_AH
 477 #define IPPROTO_AH      51
 478 #endif
 479                 case IPPROTO_AH:
 480                         nh = *cp;
 481                         advance = ah_print(cp, (const u_char *)ip);
 482                         cp += advance;
 483                         len -= advance;
 484                         goto again;
 485
 486 #ifndef IPPROTO_ESP
 487 #define IPPROTO_ESP     50
 488 #endif
 489                 case IPPROTO_ESP:
 490                     {
 491                         int enh;
 492                         advance = esp_print(cp, (const u_char *)ip, &enh);
 493                         cp += advance;
 494                         len -= advance;
 495                         if (enh < 0)
 496                                 break;
 497                         nh = enh & 0xff;
 498                         goto again;
 499                     }
 500
 501 #ifndef IPPROTO_IPCOMP
 502 #define IPPROTO_IPCOMP  108
 503 #endif
 504                 case IPPROTO_IPCOMP:
 505                     {
 506                         int enh;
 507                         advance = ipcomp_print(cp, (const u_char *)ip, &enh);
 508                         cp += advance;
 509                         len -= advance;
 510                         if (enh < 0)
 511                                 break;
 512                         nh = enh & 0xff;
 513                         goto again;
 514                     }
 515
 516                 case IPPROTO_TCP:
 517                         tcp_print(cp, len, (const u_char *)ip);
 518                         break;
 519
 520                 case IPPROTO_UDP:
 521                         udp_print(cp, len, (const u_char *)ip);
 522                         break;
 523
 524                 case IPPROTO_ICMP:
 525                         icmp_print(cp, len, (const u_char *)ip);
 526                         break;
 527
 528 #ifndef IPPROTO_IGRP
 529 #define IPPROTO_IGRP 9
 530 #endif
 531                 case IPPROTO_IGRP:
 532                         igrp_print(cp, len, (const u_char *)ip);
 533                         break;
 534
 535                 case IPPROTO_ND:
 536 #if 0
 537                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 538                                 ipaddr_string(&ip->ip_dst));
 539 #endif
 540                         (void)printf(" nd %d", len);
 541                         break;
 542
 543                 case IPPROTO_EGP:
 544                         egp_print(cp, len, (const u_char *)ip);
 545                         break;
 546
 547 #ifndef IPPROTO_OSPF
 548 #define IPPROTO_OSPF 89
 549 #endif
 550                 case IPPROTO_OSPF:
 551                         ospf_print(cp, len, (const u_char *)ip);
 552                         break;
 553
 554 #ifndef IPPROTO_IGMP
 555 #define IPPROTO_IGMP 2
 556 #endif
 557                 case IPPROTO_IGMP:
 558                         igmp_print(cp, len, (const u_char *)ip);
 559                         break;
 560
 561                 case 4:
 562                         /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 563 #if 0
 564                         if (vflag)
 565                                 (void)printf("%s > %s: ",
 566                                              ipaddr_string(&ip->ip_src),
 567                                              ipaddr_string(&ip->ip_dst));
 568 #endif
 569                         ip_print(cp, len);
 570                         if (! vflag) {
 571                                 printf(" (ipip)");
 572                                 return;
 573                         }
 574                         break;
 575
 576 #ifdef INET6
 577 #ifndef IP6PROTO_ENCAP
 578 #define IP6PROTO_ENCAP 41
 579 #endif
 580                 case IP6PROTO_ENCAP:
 581                         /* ip6-in-ip encapsulation */
 582 #if 0
 583                         if (vflag)
 584                                 (void)printf("%s > %s: ",
 585                                              ipaddr_string(&ip->ip_src),
 586                                              ipaddr_string(&ip->ip_dst));
 587 #endif
 588                         ip6_print(cp, len);
 589                         if (! vflag) {
 590                                 printf(" (encap)");
 591                                 return;
 592                         }
 593                         break;
 594 #endif /*INET6*/
 595
 596
 597 #ifndef IPPROTO_GRE
 598 #define IPPROTO_GRE 47
 599 #endif
 600                 case IPPROTO_GRE:
 601                         if (vflag)
 602                                 (void)printf("gre %s > %s: ",
 603                                              ipaddr_string(&ip->ip_src),
 604                                              ipaddr_string(&ip->ip_dst));
 605                         /* do it */
 606                         gre_print(cp, len);
 607                         if (! vflag) {
 608                                 printf(" (gre encap)");
 609                                 return;
 610                         }
 611                         break;
 612
 613 #ifndef IPPROTO_MOBILE
 614 #define IPPROTO_MOBILE 55
 615 #endif
 616                 case IPPROTO_MOBILE:
 617                         if (vflag)
 618                                 (void)printf("mobile %s > %s: ",
 619                                              ipaddr_string(&ip->ip_src),
 620                                              ipaddr_string(&ip->ip_dst));
 621                         mobile_print(cp, len);
 622                         if (! vflag) {
 623                                 printf(" (mobile encap)");
 624                                 return;
 625                         }
 626                         break;
 627
 628 #ifndef IPPROTO_PIM
 629 #define IPPROTO_PIM     103
 630 #endif
 631                 case IPPROTO_PIM:
 632                         pim_print(cp, len);
 633                         break;
 634
 635 #ifndef IPPROTO_VRRP
 636 #define IPPROTO_VRRP    112
 637 #endif
 638                 case IPPROTO_VRRP:
 639                         vrrp_print(cp, len, ip->ip_ttl);
 640                         break;
 641
 642                 default:
 643 #if 0
 644                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 645                                 ipaddr_string(&ip->ip_dst));
 646 #endif
 647                         (void)printf(" ip-proto-%d %d", nh, len);
 648                         break;
 649                 }
 650         }
 651
 652         /* Ultra quiet now means that all this stuff should be suppressed */
 653         /* res 3-Nov-98 */
 654         if (qflag > 1) return;
 655
 656
 657         /*
 658          * for fragmented datagrams, print id:size@offset.  On all
 659          * but the last stick a "+".  For unfragmented datagrams, note
 660          * the don't fragment flag.
 661          */
 662         len = len0;     /* get the original length */
 663         if (off & 0x3fff) {
 664                 /*
 665                  * if this isn't the first frag, we're missing the
 666                  * next level protocol header.  print the ip addr.
 667                  */
 668                 if (off & 0x1fff)
 669                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 670                                       ipaddr_string(&ip->ip_dst));
 671 #ifndef IP_MF
 672 #define IP_MF 0x2000
 673 #endif /* IP_MF */
 674 #ifndef IP_DF
 675 #define IP_DF 0x4000
 676 #endif /* IP_DF */
 677                 (void)printf(" (frag %d:%u@%d%s)", ntohs(ip->ip_id), len,
 678                         (off & 0x1fff) * 8,
 679                         (off & IP_MF)? "+" : "");
 680
 681         } else if (off & IP_DF)
 682                 (void)printf(" (DF)");
 683
 684         if (ip->ip_tos) {
 685                 (void)printf(" [tos 0x%x", (int)ip->ip_tos);
 686                 /* ECN bits */
 687                 if (ip->ip_tos&0x02) {
 688                         (void)printf(",ECT");
 689                         if (ip->ip_tos&0x01)
 690                                 (void)printf(",CE");
 691                 }
 692                 (void)printf("] ");
 693         }
 694
 695         if (ip->ip_ttl <= 1)
 696                 (void)printf(" [ttl %d]", (int)ip->ip_ttl);
 697
 698         if (vflag) {
 699                 int sum;
 700                 char *sep = "";
 701
 702                 printf(" (");
 703                 if (ip->ip_ttl > 1) {
 704                         (void)printf("%sttl %d", sep, (int)ip->ip_ttl);
 705                         sep = ", ";
 706                 }
 707                 if ((off & 0x3fff) == 0) {
 708                         (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id));
 709                         sep = ", ";
 710                 }
 711                 (void)printf("%slen %d", sep, (int)ntohs(ip->ip_len));
 712                 sep = ", ";
 713                 if ((u_char *)ip + hlen <= snapend) {
 714                         sum = in_cksum((const u_short *)ip, hlen, 0);
 715                         if (sum != 0) {
 716                                 (void)printf("%sbad cksum %x!", sep,
 717                                              ntohs(ip->ip_sum));
 718                                 sep = ", ";
 719                         }
 720                 }
 721                 if ((hlen -= sizeof(struct ip)) > 0) {
 722                         (void)printf("%soptlen=%d", sep, hlen);
 723                         ip_optprint((u_char *)(ip + 1), hlen);
 724                 }
 725                 printf(")");
 726         }
 727 }
 728
 729 void
 730 ipN_print(register const u_char *bp, register u_int length)
 731 {
 732         struct ip *ip, hdr;
 733
 734         ip = (struct ip *)bp;
 735         if (length < 4) {
 736                 (void)printf("truncated-ip %d", length);
 737                 return;
 738         }
 739         memcpy (&hdr, (char *)ip, 4);
 740         switch (hdr.ip_v) {
 741         case 4:
 742             ip_print (bp, length);
 743             return;
 744 #ifdef INET6
 745         case 6:
 746             ip6_print (bp, length);
 747             return;
 748 #endif
 749         default:
 750             (void)printf("unknown ip %d", hdr.ip_v);
 751             return;
 752         }
 753 }