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 1.101 2001-10-27 07:42:46 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 <netdb.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42
  43 #include "addrtoname.h"
  44 #include "interface.h"
  45 #include "extract.h"                    /* must come after interface.h */
  46
  47 #include "ip.h"
  48
  49 /* Compatibility */
  50 #ifndef IPPROTO_ND
  51 #define IPPROTO_ND      77
  52 #endif
  53
  54 /*
  55  * print the recorded route in an IP RR, LSRR or SSRR option.
  56  */
  57 static void
  58 ip_printroute(const char *type, register const u_char *cp, u_int length)
  59 {
  60         register u_int ptr = cp[2] - 1;
  61         register u_int len;
  62
  63         printf(" %s{", type);
  64         if ((length + 1) & 3)
  65                 printf(" [bad length %d]", length);
  66         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
  67                 printf(" [bad ptr %d]", cp[2]);
  68
  69         type = "";
  70         for (len = 3; len < length; len += 4) {
  71                 if (ptr == len)
  72                         type = "#";
  73                 printf("%s%s", type, ipaddr_string(&cp[len]));
  74                 type = " ";
  75         }
  76         printf("%s}", ptr == len? "#" : "");
  77 }
  78
  79 static void
  80 ip_printts(register const u_char *cp, u_int length)
  81 {
  82         register u_int ptr = cp[2] - 1;
  83         register u_int len = 0;
  84         int hoplen;
  85         char *type;
  86
  87         printf(" TS{");
  88         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
  89         if ((length - 4) & (hoplen-1))
  90                 printf("[bad length %d]", length);
  91         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
  92                 printf("[bad ptr %d]", cp[2]);
  93         switch (cp[3]&0xF) {
  94         case IPOPT_TS_TSONLY:
  95                 printf("TSONLY");
  96                 break;
  97         case IPOPT_TS_TSANDADDR:
  98                 printf("TS+ADDR");
  99                 break;
 100         /*
 101          * prespecified should really be 3, but some ones might send 2
 102          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 103          * have both values, so we have to hard-code it here.
 104          */
 105
 106         case 2:
 107                 printf("PRESPEC2.0");
 108                 break;
 109         case 3:                 /* IPOPT_TS_PRESPEC */
 110                 printf("PRESPEC");
 111                 break;
 112         default:
 113                 printf("[bad ts type %d]", cp[3]&0xF);
 114                 goto done;
 115         }
 116
 117         type = " ";
 118         for (len = 4; len < length; len += hoplen) {
 119                 if (ptr == len)
 120                         type = " ^ ";
 121                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 122                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 123                 type = " ";
 124         }
 125
 126 done:
 127         printf("%s", ptr == len ? " ^ " : "");
 128
 129         if (cp[3]>>4)
 130                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 131         else
 132                 printf("}");
 133 }
 134
 135 /*
 136  * print IP options.
 137  */
 138 static void
 139 ip_optprint(register const u_char *cp, u_int length)
 140 {
 141         register u_int len;
 142
 143         for (; length > 0; cp += len, length -= len) {
 144                 int tt = *cp;
 145
 146                 if (tt == IPOPT_NOP || tt == IPOPT_EOL)
 147                         len = 1;
 148                 else {
 149                         if (&cp[1] >= snapend) {
 150                                 printf("[|ip]");
 151                                 return;
 152                         }
 153                         len = cp[1];
 154                 }
 155                 if (len <= 0) {
 156                         printf("[|ip op len %d]", len);
 157                         return;
 158                 }
 159                 if (&cp[1] >= snapend || cp + len > snapend) {
 160                         printf("[|ip]");
 161                         return;
 162                 }
 163                 switch (tt) {
 164
 165                 case IPOPT_EOL:
 166                         printf(" EOL");
 167                         if (length > 1)
 168                                 printf("-%d", length - 1);
 169                         return;
 170
 171                 case IPOPT_NOP:
 172                         printf(" NOP");
 173                         break;
 174
 175                 case IPOPT_TS:
 176                         ip_printts(cp, len);
 177                         break;
 178
 179 #ifndef IPOPT_SECURITY
 180 #define IPOPT_SECURITY 130
 181 #endif /* IPOPT_SECURITY */
 182                 case IPOPT_SECURITY:
 183                         printf(" SECURITY{%d}", len);
 184                         break;
 185
 186                 case IPOPT_RR:
 187                         ip_printroute("RR", cp, len);
 188                         break;
 189
 190                 case IPOPT_SSRR:
 191                         ip_printroute("SSRR", cp, len);
 192                         break;
 193
 194                 case IPOPT_LSRR:
 195                         ip_printroute("LSRR", cp, len);
 196                         break;
 197
 198 #ifndef IPOPT_RA
 199 #define IPOPT_RA 148            /* router alert */
 200 #endif
 201                 case IPOPT_RA:
 202                         printf(" RA");
 203                         if (len != 4)
 204                                 printf("{%d}", len);
 205                         else if (cp[2] || cp[3])
 206                                 printf("%d.%d", cp[2], cp[3]);
 207                         break;
 208
 209                 default:
 210                         printf(" IPOPT-%d{%d}", cp[0], len);
 211                         break;
 212                 }
 213         }
 214 }
 215
 216 /*
 217  * compute an IP header checksum.
 218  * don't modifiy the packet.
 219  */
 220 u_short
 221 in_cksum(const u_short *addr, register u_int len, int csum)
 222 {
 223         int nleft = len;
 224         const u_short *w = addr;
 225         u_short answer;
 226         int sum = csum;
 227
 228         /*
 229          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 230          *  we add sequential 16 bit words to it, and at the end, fold
 231          *  back all the carry bits from the top 16 bits into the lower
 232          *  16 bits.
 233          */
 234         while (nleft > 1)  {
 235                 sum += *w++;
 236                 nleft -= 2;
 237         }
 238         if (nleft == 1)
 239                 sum += htons(*(u_char *)w<<8);
 240
 241         /*
 242          * add back carry outs from top 16 bits to low 16 bits
 243          */
 244         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 245         sum += (sum >> 16);                     /* add carry */
 246         answer = ~sum;                          /* truncate to 16 bits */
 247         return (answer);
 248 }
 249
 250 /*
 251  * print an IP datagram.
 252  */
 253 void
 254 ip_print(register const u_char *bp, register u_int length)
 255 {
 256         register const struct ip *ip;
 257         register u_int hlen, len, len0, off;
 258         register const u_char *cp;
 259         u_char nh;
 260         int advance;
 261         struct protoent *proto;
 262
 263         ip = (const struct ip *)bp;
 264 #ifdef LBL_ALIGN
 265         /*
 266          * If the IP header is not aligned, copy into abuf.
 267          * This will never happen with BPF.  It does happen raw packet
 268          * dumps from -r.
 269          */
 270         if ((long)ip & 3) {
 271                 static u_char *abuf = NULL;
 272                 static int didwarn = 0;
 273
 274                 if (abuf == NULL) {
 275                         abuf = (u_char *)malloc(snaplen);
 276                         if (abuf == NULL)
 277                                 error("ip_print: malloc");
 278                 }
 279                 memcpy((char *)abuf, (char *)ip, min(length, snaplen));
 280                 snapend += abuf - (u_char *)ip;
 281                 packetp = abuf;
 282                 ip = (struct ip *)abuf;
 283                 /* We really want libpcap to give us aligned packets */
 284                 if (!didwarn) {
 285                         warning("compensating for unaligned libpcap packets");
 286                         ++didwarn;
 287                 }
 288         }
 289 #endif
 290         if ((u_char *)(ip + 1) > snapend) {
 291                 printf("[|ip]");
 292                 return;
 293         }
 294         if (length < sizeof (struct ip)) {
 295                 (void)printf("truncated-ip %d", length);
 296                 return;
 297         }
 298         hlen = IP_HL(ip) * 4;
 299         if (hlen < sizeof (struct ip)) {
 300                 (void)printf("bad-hlen %d", hlen);
 301                 return;
 302         }
 303
 304         len = ntohs(ip->ip_len);
 305         if (length < len)
 306                 (void)printf("truncated-ip - %d bytes missing! ",
 307                         len - length);
 308         len -= hlen;
 309         len0 = len;
 310
 311         /*
 312          * If this is fragment zero, hand it to the next higher
 313          * level protocol.
 314          */
 315         off = ntohs(ip->ip_off);
 316         if ((off & 0x1fff) == 0) {
 317                 cp = (const u_char *)ip + hlen;
 318                 nh = ip->ip_p;
 319
 320 #ifndef IPPROTO_SCTP
 321 #define IPPROTO_SCTP 132
 322 #endif
 323                 if (nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
 324                     nh != IPPROTO_SCTP) {
 325                         (void)printf("%s > %s: ", ipaddr_string(&ip->ip_src),
 326                                 ipaddr_string(&ip->ip_dst));
 327                 }
 328 again:
 329                 switch (nh) {
 330
 331 #ifndef IPPROTO_AH
 332 #define IPPROTO_AH      51
 333 #endif
 334                 case IPPROTO_AH:
 335                         nh = *cp;
 336                         advance = ah_print(cp, (const u_char *)ip);
 337                         cp += advance;
 338                         len -= advance;
 339                         goto again;
 340
 341 #ifndef IPPROTO_ESP
 342 #define IPPROTO_ESP     50
 343 #endif
 344                 case IPPROTO_ESP:
 345                     {
 346                         int enh, padlen;
 347                         advance = esp_print(cp, (const u_char *)ip, &enh, &padlen);
 348                         cp += advance;
 349                         len -= advance + padlen;
 350                         if (enh < 0)
 351                                 break;
 352                         nh = enh & 0xff;
 353                         goto again;
 354                     }
 355
 356 #ifndef IPPROTO_IPCOMP
 357 #define IPPROTO_IPCOMP  108
 358 #endif
 359                 case IPPROTO_IPCOMP:
 360                     {
 361                         int enh;
 362                         advance = ipcomp_print(cp, (const u_char *)ip, &enh);
 363                         cp += advance;
 364                         len -= advance;
 365                         if (enh < 0)
 366                                 break;
 367                         nh = enh & 0xff;
 368                         goto again;
 369                     }
 370
 371                 case IPPROTO_SCTP:
 372                         sctp_print(cp, (const u_char *)ip, len);
 373                         break;
 374
 375                 case IPPROTO_TCP:
 376                         tcp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
 377                         break;
 378
 379                 case IPPROTO_UDP:
 380                         udp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
 381                         break;
 382
 383                 case IPPROTO_ICMP:
 384                         icmp_print(cp, len, (const u_char *)ip);
 385                         break;
 386
 387 #ifndef IPPROTO_IGRP
 388 #define IPPROTO_IGRP 9
 389 #endif
 390                 case IPPROTO_IGRP:
 391                         igrp_print(cp, len, (const u_char *)ip);
 392                         break;
 393
 394                 case IPPROTO_ND:
 395                         (void)printf(" nd %d", len);
 396                         break;
 397
 398                 case IPPROTO_EGP:
 399                         egp_print(cp, len, (const u_char *)ip);
 400                         break;
 401
 402 #ifndef IPPROTO_OSPF
 403 #define IPPROTO_OSPF 89
 404 #endif
 405                 case IPPROTO_OSPF:
 406                         ospf_print(cp, len, (const u_char *)ip);
 407                         break;
 408
 409 #ifndef IPPROTO_IGMP
 410 #define IPPROTO_IGMP 2
 411 #endif
 412                 case IPPROTO_IGMP:
 413                         igmp_print(cp, len);
 414                         break;
 415
 416                 case 4:
 417                         /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 418                         ip_print(cp, len);
 419                         if (! vflag) {
 420                                 printf(" (ipip-proto-4)");
 421                                 return;
 422                         }
 423                         break;
 424
 425 #ifdef INET6
 426 #ifndef IP6PROTO_ENCAP
 427 #define IP6PROTO_ENCAP 41
 428 #endif
 429                 case IP6PROTO_ENCAP:
 430                         /* ip6-in-ip encapsulation */
 431                         ip6_print(cp, len);
 432                         break;
 433 #endif /*INET6*/
 434
 435
 436 #ifndef IPPROTO_GRE
 437 #define IPPROTO_GRE 47
 438 #endif
 439                 case IPPROTO_GRE:
 440                         /* do it */
 441                         gre_print(cp, len);
 442                         break;
 443
 444 #ifndef IPPROTO_MOBILE
 445 #define IPPROTO_MOBILE 55
 446 #endif
 447                 case IPPROTO_MOBILE:
 448                         mobile_print(cp, len);
 449                         break;
 450
 451 #ifndef IPPROTO_PIM
 452 #define IPPROTO_PIM     103
 453 #endif
 454                 case IPPROTO_PIM:
 455                         pim_print(cp, len);
 456                         break;
 457
 458 #ifndef IPPROTO_VRRP
 459 #define IPPROTO_VRRP    112
 460 #endif
 461                 case IPPROTO_VRRP:
 462                         vrrp_print(cp, len, ip->ip_ttl);
 463                         break;
 464
 465                 default:
 466                         if ((proto = getprotobynumber(nh)) != NULL)
 467                                 (void)printf(" %s", proto->p_name);
 468                         else
 469                                 (void)printf(" ip-proto-%d", nh);
 470                         printf(" %d", len);
 471                         break;
 472                 }
 473         }
 474
 475         /* Ultra quiet now means that all this stuff should be suppressed */
 476         /* res 3-Nov-98 */
 477         if (qflag > 1) return;
 478
 479
 480         /*
 481          * for fragmented datagrams, print id:size@offset.  On all
 482          * but the last stick a "+".  For unfragmented datagrams, note
 483          * the don't fragment flag.
 484          */
 485         len = len0;     /* get the original length */
 486         if (off & 0x3fff) {
 487                 /*
 488                  * if this isn't the first frag, we're missing the
 489                  * next level protocol header.  print the ip addr
 490                  * and the protocol.
 491                  */
 492                 if (off & 0x1fff) {
 493                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 494                                       ipaddr_string(&ip->ip_dst));
 495                         if ((proto = getprotobynumber(ip->ip_p)) != NULL)
 496                                 (void)printf(" %s", proto->p_name);
 497                         else
 498                                 (void)printf(" ip-proto-%d", ip->ip_p);
 499                 }
 500 #ifndef IP_MF
 501 #define IP_MF 0x2000
 502 #endif /* IP_MF */
 503 #ifndef IP_DF
 504 #define IP_DF 0x4000
 505 #endif /* IP_DF */
 506                 (void)printf(" (frag %d:%u@%d%s)", ntohs(ip->ip_id), len,
 507                         (off & 0x1fff) * 8,
 508                         (off & IP_MF)? "+" : "");
 509
 510         } else if (off & IP_DF)
 511                 (void)printf(" (DF)");
 512
 513         if (ip->ip_tos) {
 514                 (void)printf(" [tos 0x%x", (int)ip->ip_tos);
 515                 /* ECN bits */
 516                 if (ip->ip_tos & 0x03) {
 517                         switch (ip->ip_tos & 0x03) {
 518                         case 1:
 519                                 (void)printf(",ECT(1)");
 520                                 break;
 521                         case 2:
 522                                 (void)printf(",ECT(0)");
 523                                 break;
 524                         case 3:
 525                                 (void)printf(",CE");
 526                         }
 527                 }
 528                 (void)printf("] ");
 529         }
 530
 531         if (ip->ip_ttl <= 1)
 532                 (void)printf(" [ttl %d]", (int)ip->ip_ttl);
 533
 534         if (vflag) {
 535                 int sum;
 536                 char *sep = "";
 537
 538                 printf(" (");
 539                 if (ip->ip_ttl > 1) {
 540                         (void)printf("%sttl %d", sep, (int)ip->ip_ttl);
 541                         sep = ", ";
 542                 }
 543                 if ((off & 0x3fff) == 0) {
 544                         (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id));
 545                         sep = ", ";
 546                 }
 547                 (void)printf("%slen %d", sep, (int)ntohs(ip->ip_len));
 548                 sep = ", ";
 549                 if ((u_char *)ip + hlen <= snapend) {
 550                         sum = in_cksum((const u_short *)ip, hlen, 0);
 551                         if (sum != 0) {
 552                                 (void)printf("%sbad cksum %x!", sep,
 553                                              ntohs(ip->ip_sum));
 554                                 sep = ", ";
 555                         }
 556                 }
 557                 if ((hlen -= sizeof(struct ip)) > 0) {
 558                         (void)printf("%soptlen=%d", sep, hlen);
 559                         ip_optprint((u_char *)(ip + 1), hlen);
 560                 }
 561                 printf(")");
 562         }
 563 }
 564
 565 void
 566 ipN_print(register const u_char *bp, register u_int length)
 567 {
 568         struct ip *ip, hdr;
 569
 570         ip = (struct ip *)bp;
 571         if (length < 4) {
 572                 (void)printf("truncated-ip %d", length);
 573                 return;
 574         }
 575         memcpy (&hdr, (char *)ip, 4);
 576         switch (IP_V(&hdr)) {
 577         case 4:
 578                 ip_print (bp, length);
 579                 return;
 580 #ifdef INET6
 581         case 6:
 582                 ip6_print (bp, length);
 583                 return;
 584 #endif
 585         default:
 586                 (void)printf("unknown ip %d", IP_V(&hdr));
 587                 return;
 588         }
 589 }