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 1.88 2000-09-29 04:58:40 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
  37 #include <stdio.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <unistd.h>
  41
  42 #include "addrtoname.h"
  43 #include "interface.h"
  44 #include "extract.h"                    /* must come after interface.h */
  45
  46 #include "ip.h"
  47
  48 /* Compatibility */
  49 #ifndef IPPROTO_ND
  50 #define IPPROTO_ND      77
  51 #endif
  52
  53 #ifndef IN_CLASSD
  54 #define IN_CLASSD(i) (((int32_t)(i) & 0xf0000000) == 0xe0000000)
  55 #endif
  56
  57 /* (following from ipmulti/mrouted/prune.h) */
  58
  59 /*
  60  * The packet format for a traceroute request.
  61  */
  62 struct tr_query {
  63         u_int  tr_src;                  /* traceroute source */
  64         u_int  tr_dst;                  /* traceroute destination */
  65         u_int  tr_raddr;                /* traceroute response address */
  66         u_int  tr_rttlqid;              /* response ttl and qid */
  67 };
  68
  69 #define TR_GETTTL(x)            (int)(((x) >> 24) & 0xff)
  70 #define TR_GETQID(x)            ((x) & 0x00ffffff)
  71
  72 /*
  73  * Traceroute response format.  A traceroute response has a tr_query at the
  74  * beginning, followed by one tr_resp for each hop taken.
  75  */
  76 struct tr_resp {
  77         u_int tr_qarr;                  /* query arrival time */
  78         u_int tr_inaddr;                /* incoming interface address */
  79         u_int tr_outaddr;               /* outgoing interface address */
  80         u_int tr_rmtaddr;               /* parent address in source tree */
  81         u_int tr_vifin;                 /* input packet count on interface */
  82         u_int tr_vifout;                /* output packet count on interface */
  83         u_int tr_pktcnt;                /* total incoming packets for src-grp */
  84         u_char  tr_rproto;              /* routing proto deployed on router */
  85         u_char  tr_fttl;                /* ttl required to forward on outvif */
  86         u_char  tr_smask;               /* subnet mask for src addr */
  87         u_char  tr_rflags;              /* forwarding error codes */
  88 };
  89
  90 /* defs within mtrace */
  91 #define TR_QUERY 1
  92 #define TR_RESP 2
  93
  94 /* fields for tr_rflags (forwarding error codes) */
  95 #define TR_NO_ERR       0
  96 #define TR_WRONG_IF     1
  97 #define TR_PRUNED       2
  98 #define TR_OPRUNED      3
  99 #define TR_SCOPED       4
 100 #define TR_NO_RTE       5
 101 #define TR_NO_FWD       7
 102 #define TR_NO_SPACE     0x81
 103 #define TR_OLD_ROUTER   0x82
 104
 105 /* fields for tr_rproto (routing protocol) */
 106 #define TR_PROTO_DVMRP  1
 107 #define TR_PROTO_MOSPF  2
 108 #define TR_PROTO_PIM    3
 109 #define TR_PROTO_CBT    4
 110
 111 static void print_mtrace(register const u_char *bp, register u_int len)
 112 {
 113         register struct tr_query *tr = (struct tr_query *)(bp + 8);
 114
 115         printf("mtrace %lu: %s to %s reply-to %s",
 116                 (u_long)TR_GETQID(ntohl(tr->tr_rttlqid)),
 117                 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
 118                 ipaddr_string(&tr->tr_raddr));
 119         if (IN_CLASSD(ntohl(tr->tr_raddr)))
 120                 printf(" with-ttl %d", TR_GETTTL(ntohl(tr->tr_rttlqid)));
 121 }
 122
 123 static void print_mresp(register const u_char *bp, register u_int len)
 124 {
 125         register struct tr_query *tr = (struct tr_query *)(bp + 8);
 126
 127         printf("mresp %lu: %s to %s reply-to %s",
 128                 (u_long)TR_GETQID(ntohl(tr->tr_rttlqid)),
 129                 ipaddr_string(&tr->tr_src), ipaddr_string(&tr->tr_dst),
 130                 ipaddr_string(&tr->tr_raddr));
 131         if (IN_CLASSD(ntohl(tr->tr_raddr)))
 132                 printf(" with-ttl %d", TR_GETTTL(ntohl(tr->tr_rttlqid)));
 133 }
 134
 135 static void
 136 igmp_print(register const u_char *bp, register u_int len,
 137            register const u_char *bp2)
 138 {
 139         register const struct ip *ip;
 140
 141         ip = (const struct ip *)bp2;
 142         (void)printf("%s > %s: ",
 143                 ipaddr_string(&ip->ip_src),
 144                 ipaddr_string(&ip->ip_dst));
 145
 146         if (qflag) {
 147                 (void)printf("igmp");
 148                 return;
 149         }
 150
 151         TCHECK2(bp[0], 8);
 152         switch (bp[0]) {
 153         case 0x11:
 154                 (void)printf("igmp query");
 155                 if (EXTRACT_32BITS(&bp[4]))
 156                         (void)printf(" [gaddr %s]", ipaddr_string(&bp[4]));
 157                 if (len != 8)
 158                         (void)printf(" [len %d]", len);
 159                 break;
 160         case 0x12:
 161                 (void)printf("igmp v1 report %s", ipaddr_string(&bp[4]));
 162                 if (len != 8)
 163                         (void)printf(" [len %d]", len);
 164                 break;
 165         case 0x16:
 166                 (void)printf("igmp v2 report %s", ipaddr_string(&bp[4]));
 167                 break;
 168         case 0x17:
 169                 (void)printf("igmp leave %s", ipaddr_string(&bp[4]));
 170                 break;
 171         case 0x13:
 172                 (void)printf("igmp dvmrp");
 173                 if (len < 8)
 174                         (void)printf(" [len %d]", len);
 175                 else
 176                         dvmrp_print(bp, len);
 177                 break;
 178         case 0x14:
 179                 (void)printf("igmp pimv1");
 180                 pimv1_print(bp, len);
 181                 break;
 182         case 0x1e:
 183                 print_mresp(bp, len);
 184                 break;
 185         case 0x1f:
 186                 print_mtrace(bp, len);
 187                 break;
 188         default:
 189                 (void)printf("igmp-%d", bp[0]);
 190                 break;
 191         }
 192
 193         if (vflag && TTEST2(bp[0], len)) {
 194                 /* Check the IGMP checksum */
 195                 if (in_cksum((const u_short*)bp, len, 0))
 196                         printf(" bad igmp cksum %x!", EXTRACT_16BITS(&bp[2]));
 197         }
 198         return;
 199 trunc:
 200         fputs("[|igmp]", stdout);
 201 }
 202
 203 /*
 204  * print the recorded route in an IP RR, LSRR or SSRR option.
 205  */
 206 static void
 207 ip_printroute(const char *type, register const u_char *cp, u_int length)
 208 {
 209         register u_int ptr = cp[2] - 1;
 210         register u_int len;
 211
 212         printf(" %s{", type);
 213         if ((length + 1) & 3)
 214                 printf(" [bad length %d]", length);
 215         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
 216                 printf(" [bad ptr %d]", cp[2]);
 217
 218         type = "";
 219         for (len = 3; len < length; len += 4) {
 220                 if (ptr == len)
 221                         type = "#";
 222                 printf("%s%s", type, ipaddr_string(&cp[len]));
 223                 type = " ";
 224         }
 225         printf("%s}", ptr == len? "#" : "");
 226 }
 227
 228 static void
 229 ip_printts(register const u_char *cp, u_int length)
 230 {
 231         register u_int ptr = cp[2] - 1;
 232         register u_int len = 0;
 233         int hoplen;
 234         char *type;
 235
 236         printf(" TS{");
 237         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
 238         if ((length - 4) & (hoplen-1))
 239                 printf("[bad length %d]", length);
 240         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
 241                 printf("[bad ptr %d]", cp[2]);
 242         switch (cp[3]&0xF) {
 243         case IPOPT_TS_TSONLY:
 244                 printf("TSONLY");
 245                 break;
 246         case IPOPT_TS_TSANDADDR:
 247                 printf("TS+ADDR");
 248                 break;
 249         /*
 250          * prespecified should really be 3, but some ones might send 2
 251          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 252          * have both values, so we have to hard-code it here.
 253          */
 254
 255         case 2:
 256                 printf("PRESPEC2.0");
 257                 break;
 258         case 3:                 /* IPOPT_TS_PRESPEC */
 259                 printf("PRESPEC");
 260                 break;
 261         default:
 262                 printf("[bad ts type %d]", cp[3]&0xF);
 263                 goto done;
 264         }
 265
 266         type = " ";
 267         for (len = 4; len < length; len += hoplen) {
 268                 if (ptr == len)
 269                         type = " ^ ";
 270                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 271                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 272                 type = " ";
 273         }
 274
 275 done:
 276         printf("%s", ptr == len ? " ^ " : "");
 277
 278         if (cp[3]>>4)
 279                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 280         else
 281                 printf("}");
 282 }
 283
 284 /*
 285  * print IP options.
 286  */
 287 static void
 288 ip_optprint(register const u_char *cp, u_int length)
 289 {
 290         register u_int len;
 291
 292         for (; length > 0; cp += len, length -= len) {
 293                 int tt = *cp;
 294
 295                 if (tt == IPOPT_NOP || tt == IPOPT_EOL)
 296                         len = 1;
 297                 else {
 298                         if (&cp[1] >= snapend) {
 299                                 printf("[|ip]");
 300                                 return;
 301                         }
 302                         len = cp[1];
 303                 }
 304                 if (len <= 0) {
 305                         printf("[|ip op len %d]", len);
 306                         return;
 307                 }
 308                 if (&cp[1] >= snapend || cp + len > snapend) {
 309                         printf("[|ip]");
 310                         return;
 311                 }
 312                 switch (tt) {
 313
 314                 case IPOPT_EOL:
 315                         printf(" EOL");
 316                         if (length > 1)
 317                                 printf("-%d", length - 1);
 318                         return;
 319
 320                 case IPOPT_NOP:
 321                         printf(" NOP");
 322                         break;
 323
 324                 case IPOPT_TS:
 325                         ip_printts(cp, len);
 326                         break;
 327
 328 #ifndef IPOPT_SECURITY
 329 #define IPOPT_SECURITY 130
 330 #endif /* IPOPT_SECURITY */
 331                 case IPOPT_SECURITY:
 332                         printf(" SECURITY{%d}", len);
 333                         break;
 334
 335                 case IPOPT_RR:
 336                         ip_printroute("RR", cp, len);
 337                         break;
 338
 339                 case IPOPT_SSRR:
 340                         ip_printroute("SSRR", cp, len);
 341                         break;
 342
 343                 case IPOPT_LSRR:
 344                         ip_printroute("LSRR", cp, len);
 345                         break;
 346
 347 #ifndef IPOPT_RA
 348 #define IPOPT_RA 148            /* router alert */
 349 #endif
 350                 case IPOPT_RA:
 351                         printf(" RA");
 352                         if (len != 4)
 353                                 printf("{%d}", len);
 354                         else if (cp[2] || cp[3])
 355                                 printf("%d.%d", cp[2], cp[3]);
 356                         break;
 357
 358                 default:
 359                         printf(" IPOPT-%d{%d}", cp[0], len);
 360                         break;
 361                 }
 362         }
 363 }
 364
 365 /*
 366  * compute an IP header checksum.
 367  * don't modifiy the packet.
 368  */
 369 u_short
 370 in_cksum(const u_short *addr, register int len, u_short csum)
 371 {
 372         int nleft = len;
 373         const u_short *w = addr;
 374         u_short answer;
 375         int sum = csum;
 376
 377         /*
 378          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 379          *  we add sequential 16 bit words to it, and at the end, fold
 380          *  back all the carry bits from the top 16 bits into the lower
 381          *  16 bits.
 382          */
 383         while (nleft > 1)  {
 384                 sum += *w++;
 385                 nleft -= 2;
 386         }
 387         if (nleft == 1)
 388                 sum += htons(*(u_char *)w<<8);
 389
 390         /*
 391          * add back carry outs from top 16 bits to low 16 bits
 392          */
 393         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 394         sum += (sum >> 16);                     /* add carry */
 395         answer = ~sum;                          /* truncate to 16 bits */
 396         return (answer);
 397 }
 398
 399 /*
 400  * print an IP datagram.
 401  */
 402 void
 403 ip_print(register const u_char *bp, register u_int length)
 404 {
 405         register const struct ip *ip;
 406         register u_int hlen, len, len0, off;
 407         register const u_char *cp;
 408         u_char nh;
 409         int advance;
 410
 411         ip = (const struct ip *)bp;
 412 #ifdef LBL_ALIGN
 413         /*
 414          * If the IP header is not aligned, copy into abuf.
 415          * This will never happen with BPF.  It does happen raw packet
 416          * dumps from -r.
 417          */
 418         if ((long)ip & 3) {
 419                 static u_char *abuf = NULL;
 420                 static int didwarn = 0;
 421
 422                 if (abuf == NULL) {
 423                         abuf = (u_char *)malloc(snaplen);
 424                         if (abuf == NULL)
 425                                 error("ip_print: malloc");
 426                 }
 427                 memcpy((char *)abuf, (char *)ip, min(length, snaplen));
 428                 snapend += abuf - (u_char *)ip;
 429                 packetp = abuf;
 430                 ip = (struct ip *)abuf;
 431                 /* We really want libpcap to give us aligned packets */
 432                 if (!didwarn) {
 433                         warning("compensating for unaligned libpcap packets");
 434                         ++didwarn;
 435                 }
 436         }
 437 #endif
 438         if ((u_char *)(ip + 1) > snapend) {
 439                 printf("[|ip]");
 440                 return;
 441         }
 442         if (length < sizeof (struct ip)) {
 443                 (void)printf("truncated-ip %d", length);
 444                 return;
 445         }
 446         hlen = ip->ip_hl * 4;
 447         if (hlen < sizeof (struct ip)) {
 448                 (void)printf("bad-hlen %d", hlen);
 449                 return;
 450         }
 451
 452         len = ntohs(ip->ip_len);
 453         if (length < len)
 454                 (void)printf("truncated-ip - %d bytes missing!",
 455                         len - length);
 456         len -= hlen;
 457         len0 = len;
 458
 459         /*
 460          * If this is fragment zero, hand it to the next higher
 461          * level protocol.
 462          */
 463         off = ntohs(ip->ip_off);
 464         if ((off & 0x1fff) == 0) {
 465                 cp = (const u_char *)ip + hlen;
 466                 nh = ip->ip_p;
 467
 468                 if (nh != IPPROTO_TCP && nh != IPPROTO_UDP) {
 469                         (void)printf("%s > %s: ", ipaddr_string(&ip->ip_src),
 470                                 ipaddr_string(&ip->ip_dst));
 471                 }
 472 again:
 473                 switch (nh) {
 474
 475 #ifndef IPPROTO_AH
 476 #define IPPROTO_AH      51
 477 #endif
 478                 case IPPROTO_AH:
 479                         nh = *cp;
 480                         advance = ah_print(cp, (const u_char *)ip);
 481                         cp += advance;
 482                         len -= advance;
 483                         goto again;
 484
 485 #ifndef IPPROTO_ESP
 486 #define IPPROTO_ESP     50
 487 #endif
 488                 case IPPROTO_ESP:
 489                     {
 490                         int enh;
 491                         advance = esp_print(cp, (const u_char *)ip, &enh);
 492                         cp += advance;
 493                         len -= advance;
 494                         if (enh < 0)
 495                                 break;
 496                         nh = enh & 0xff;
 497                         goto again;
 498                     }
 499
 500 #ifndef IPPROTO_IPCOMP
 501 #define IPPROTO_IPCOMP  108
 502 #endif
 503                 case IPPROTO_IPCOMP:
 504                     {
 505                         int enh;
 506                         advance = ipcomp_print(cp, (const u_char *)ip, &enh);
 507                         cp += advance;
 508                         len -= advance;
 509                         if (enh < 0)
 510                                 break;
 511                         nh = enh & 0xff;
 512                         goto again;
 513                     }
 514
 515                 case IPPROTO_TCP:
 516                         tcp_print(cp, len, (const u_char *)ip);
 517                         break;
 518
 519                 case IPPROTO_UDP:
 520                         udp_print(cp, len, (const u_char *)ip);
 521                         break;
 522
 523                 case IPPROTO_ICMP:
 524                         icmp_print(cp, len, (const u_char *)ip);
 525                         break;
 526
 527 #ifndef IPPROTO_IGRP
 528 #define IPPROTO_IGRP 9
 529 #endif
 530                 case IPPROTO_IGRP:
 531                         igrp_print(cp, len, (const u_char *)ip);
 532                         break;
 533
 534                 case IPPROTO_ND:
 535 #if 0
 536                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 537                                 ipaddr_string(&ip->ip_dst));
 538 #endif
 539                         (void)printf(" nd %d", len);
 540                         break;
 541
 542                 case IPPROTO_EGP:
 543                         egp_print(cp, len, (const u_char *)ip);
 544                         break;
 545
 546 #ifndef IPPROTO_OSPF
 547 #define IPPROTO_OSPF 89
 548 #endif
 549                 case IPPROTO_OSPF:
 550                         ospf_print(cp, len, (const u_char *)ip);
 551                         break;
 552
 553 #ifndef IPPROTO_IGMP
 554 #define IPPROTO_IGMP 2
 555 #endif
 556                 case IPPROTO_IGMP:
 557                         igmp_print(cp, len, (const u_char *)ip);
 558                         break;
 559
 560                 case 4:
 561                         /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 562 #if 0
 563                         if (vflag)
 564                                 (void)printf("%s > %s: ",
 565                                              ipaddr_string(&ip->ip_src),
 566                                              ipaddr_string(&ip->ip_dst));
 567 #endif
 568                         ip_print(cp, len);
 569                         if (! vflag) {
 570                                 printf(" (ipip)");
 571                                 return;
 572                         }
 573                         break;
 574
 575 #ifdef INET6
 576 #ifndef IP6PROTO_ENCAP
 577 #define IP6PROTO_ENCAP 41
 578 #endif
 579                 case IP6PROTO_ENCAP:
 580                         /* ip6-in-ip encapsulation */
 581 #if 0
 582                         if (vflag)
 583                                 (void)printf("%s > %s: ",
 584                                              ipaddr_string(&ip->ip_src),
 585                                              ipaddr_string(&ip->ip_dst));
 586 #endif
 587                         ip6_print(cp, len);
 588                         if (! vflag) {
 589                                 printf(" (encap)");
 590                                 return;
 591                         }
 592                         break;
 593 #endif /*INET6*/
 594
 595
 596 #ifndef IPPROTO_GRE
 597 #define IPPROTO_GRE 47
 598 #endif
 599                 case IPPROTO_GRE:
 600                         if (vflag)
 601                                 (void)printf("gre %s > %s: ",
 602                                              ipaddr_string(&ip->ip_src),
 603                                              ipaddr_string(&ip->ip_dst));
 604                         /* do it */
 605                         gre_print(cp, len);
 606                         if (! vflag) {
 607                                 printf(" (gre encap)");
 608                                 return;
 609                         }
 610                         break;
 611
 612 #ifndef IPPROTO_MOBILE
 613 #define IPPROTO_MOBILE 55
 614 #endif
 615                 case IPPROTO_MOBILE:
 616                         if (vflag)
 617                                 (void)printf("mobile %s > %s: ",
 618                                              ipaddr_string(&ip->ip_src),
 619                                              ipaddr_string(&ip->ip_dst));
 620                         mobile_print(cp, len);
 621                         if (! vflag) {
 622                                 printf(" (mobile encap)");
 623                                 return;
 624                         }
 625                         break;
 626
 627 #ifndef IPPROTO_PIM
 628 #define IPPROTO_PIM     103
 629 #endif
 630                 case IPPROTO_PIM:
 631                         pim_print(cp, len);
 632                         break;
 633
 634 #ifndef IPPROTO_VRRP
 635 #define IPPROTO_VRRP    112
 636 #endif
 637                 case IPPROTO_VRRP:
 638                         vrrp_print(cp, len, ip->ip_ttl);
 639                         break;
 640
 641                 default:
 642 #if 0
 643                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 644                                 ipaddr_string(&ip->ip_dst));
 645 #endif
 646                         (void)printf(" ip-proto-%d %d", nh, len);
 647                         break;
 648                 }
 649         }
 650
 651         /* Ultra quiet now means that all this stuff should be suppressed */
 652         /* res 3-Nov-98 */
 653         if (qflag > 1) return;
 654
 655
 656         /*
 657          * for fragmented datagrams, print id:size@offset.  On all
 658          * but the last stick a "+".  For unfragmented datagrams, note
 659          * the don't fragment flag.
 660          */
 661         len = len0;     /* get the original length */
 662         if (off & 0x3fff) {
 663                 /*
 664                  * if this isn't the first frag, we're missing the
 665                  * next level protocol header.  print the ip addr.
 666                  */
 667                 if (off & 0x1fff)
 668                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 669                                       ipaddr_string(&ip->ip_dst));
 670 #ifndef IP_MF
 671 #define IP_MF 0x2000
 672 #endif /* IP_MF */
 673 #ifndef IP_DF
 674 #define IP_DF 0x4000
 675 #endif /* IP_DF */
 676                 (void)printf(" (frag %d:%u@%d%s)", ntohs(ip->ip_id), len,
 677                         (off & 0x1fff) * 8,
 678                         (off & IP_MF)? "+" : "");
 679
 680         } else if (off & IP_DF)
 681                 (void)printf(" (DF)");
 682
 683         if (ip->ip_tos) {
 684                 (void)printf(" [tos 0x%x", (int)ip->ip_tos);
 685                 /* ECN bits */
 686                 if (ip->ip_tos&0x02) {
 687                         (void)printf(",ECT");
 688                         if (ip->ip_tos&0x01)
 689                                 (void)printf(",CE");
 690                 }
 691                 (void)printf("] ");
 692         }
 693
 694         if (ip->ip_ttl <= 1)
 695                 (void)printf(" [ttl %d]", (int)ip->ip_ttl);
 696
 697         if (vflag) {
 698                 int sum;
 699                 char *sep = "";
 700
 701                 printf(" (");
 702                 if (ip->ip_ttl > 1) {
 703                         (void)printf("%sttl %d", sep, (int)ip->ip_ttl);
 704                         sep = ", ";
 705                 }
 706                 if ((off & 0x3fff) == 0) {
 707                         (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id));
 708                         sep = ", ";
 709                 }
 710                 (void)printf("%slen %d", sep, (int)ntohs(ip->ip_len));
 711                 sep = ", ";
 712                 if ((u_char *)ip + hlen <= snapend) {
 713                         sum = in_cksum((const u_short *)ip, hlen, 0);
 714                         if (sum != 0) {
 715                                 (void)printf("%sbad cksum %x!", sep,
 716                                              ntohs(ip->ip_sum));
 717                                 sep = ", ";
 718                         }
 719                 }
 720                 if ((hlen -= sizeof(struct ip)) > 0) {
 721                         (void)printf("%soptlen=%d", sep, hlen);
 722                         ip_optprint((u_char *)(ip + 1), hlen);
 723                 }
 724                 printf(")");
 725         }
 726 }
 727
 728 void
 729 ipN_print(register const u_char *bp, register u_int length)
 730 {
 731         struct ip *ip, hdr;
 732
 733         ip = (struct ip *)bp;
 734         if (length < 4) {
 735                 (void)printf("truncated-ip %d", length);
 736                 return;
 737         }
 738         memcpy (&hdr, (char *)ip, 4);
 739         switch (hdr.ip_v) {
 740         case 4:
 741             ip_print (bp, length);
 742             return;
 743 #ifdef INET6
 744         case 6:
 745             ip6_print (bp, length);
 746             return;
 747 #endif
 748         default:
 749             (void)printf("unknown ip %d", hdr.ip_v);
 750             return;
 751         }
 752 }