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 1.98 2001-06-15 22:17:33 fenner 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 /*
  54  * print the recorded route in an IP RR, LSRR or SSRR option.
  55  */
  56 static void
  57 ip_printroute(const char *type, register const u_char *cp, u_int length)
  58 {
  59         register u_int ptr = cp[2] - 1;
  60         register u_int len;
  61
  62         printf(" %s{", type);
  63         if ((length + 1) & 3)
  64                 printf(" [bad length %d]", length);
  65         if (ptr < 3 || ((ptr + 1) & 3) || ptr > length + 1)
  66                 printf(" [bad ptr %d]", cp[2]);
  67
  68         type = "";
  69         for (len = 3; len < length; len += 4) {
  70                 if (ptr == len)
  71                         type = "#";
  72                 printf("%s%s", type, ipaddr_string(&cp[len]));
  73                 type = " ";
  74         }
  75         printf("%s}", ptr == len? "#" : "");
  76 }
  77
  78 static void
  79 ip_printts(register const u_char *cp, u_int length)
  80 {
  81         register u_int ptr = cp[2] - 1;
  82         register u_int len = 0;
  83         int hoplen;
  84         char *type;
  85
  86         printf(" TS{");
  87         hoplen = ((cp[3]&0xF) != IPOPT_TS_TSONLY) ? 8 : 4;
  88         if ((length - 4) & (hoplen-1))
  89                 printf("[bad length %d]", length);
  90         if (ptr < 4 || ((ptr - 4) & (hoplen-1)) || ptr > length + 1)
  91                 printf("[bad ptr %d]", cp[2]);
  92         switch (cp[3]&0xF) {
  93         case IPOPT_TS_TSONLY:
  94                 printf("TSONLY");
  95                 break;
  96         case IPOPT_TS_TSANDADDR:
  97                 printf("TS+ADDR");
  98                 break;
  99         /*
 100          * prespecified should really be 3, but some ones might send 2
 101          * instead, and the IPOPT_TS_PRESPEC constant can apparently
 102          * have both values, so we have to hard-code it here.
 103          */
 104
 105         case 2:
 106                 printf("PRESPEC2.0");
 107                 break;
 108         case 3:                 /* IPOPT_TS_PRESPEC */
 109                 printf("PRESPEC");
 110                 break;
 111         default:
 112                 printf("[bad ts type %d]", cp[3]&0xF);
 113                 goto done;
 114         }
 115
 116         type = " ";
 117         for (len = 4; len < length; len += hoplen) {
 118                 if (ptr == len)
 119                         type = " ^ ";
 120                 printf("%s%d@%s", type, EXTRACT_32BITS(&cp[len+hoplen-4]),
 121                        hoplen!=8 ? "" : ipaddr_string(&cp[len]));
 122                 type = " ";
 123         }
 124
 125 done:
 126         printf("%s", ptr == len ? " ^ " : "");
 127
 128         if (cp[3]>>4)
 129                 printf(" [%d hops not recorded]} ", cp[3]>>4);
 130         else
 131                 printf("}");
 132 }
 133
 134 /*
 135  * print IP options.
 136  */
 137 static void
 138 ip_optprint(register const u_char *cp, u_int length)
 139 {
 140         register u_int len;
 141
 142         for (; length > 0; cp += len, length -= len) {
 143                 int tt = *cp;
 144
 145                 if (tt == IPOPT_NOP || tt == IPOPT_EOL)
 146                         len = 1;
 147                 else {
 148                         if (&cp[1] >= snapend) {
 149                                 printf("[|ip]");
 150                                 return;
 151                         }
 152                         len = cp[1];
 153                 }
 154                 if (len <= 0) {
 155                         printf("[|ip op len %d]", len);
 156                         return;
 157                 }
 158                 if (&cp[1] >= snapend || cp + len > snapend) {
 159                         printf("[|ip]");
 160                         return;
 161                 }
 162                 switch (tt) {
 163
 164                 case IPOPT_EOL:
 165                         printf(" EOL");
 166                         if (length > 1)
 167                                 printf("-%d", length - 1);
 168                         return;
 169
 170                 case IPOPT_NOP:
 171                         printf(" NOP");
 172                         break;
 173
 174                 case IPOPT_TS:
 175                         ip_printts(cp, len);
 176                         break;
 177
 178 #ifndef IPOPT_SECURITY
 179 #define IPOPT_SECURITY 130
 180 #endif /* IPOPT_SECURITY */
 181                 case IPOPT_SECURITY:
 182                         printf(" SECURITY{%d}", len);
 183                         break;
 184
 185                 case IPOPT_RR:
 186                         ip_printroute("RR", cp, len);
 187                         break;
 188
 189                 case IPOPT_SSRR:
 190                         ip_printroute("SSRR", cp, len);
 191                         break;
 192
 193                 case IPOPT_LSRR:
 194                         ip_printroute("LSRR", cp, len);
 195                         break;
 196
 197 #ifndef IPOPT_RA
 198 #define IPOPT_RA 148            /* router alert */
 199 #endif
 200                 case IPOPT_RA:
 201                         printf(" RA");
 202                         if (len != 4)
 203                                 printf("{%d}", len);
 204                         else if (cp[2] || cp[3])
 205                                 printf("%d.%d", cp[2], cp[3]);
 206                         break;
 207
 208                 default:
 209                         printf(" IPOPT-%d{%d}", cp[0], len);
 210                         break;
 211                 }
 212         }
 213 }
 214
 215 /*
 216  * compute an IP header checksum.
 217  * don't modifiy the packet.
 218  */
 219 u_short
 220 in_cksum(const u_short *addr, register int len, u_short csum)
 221 {
 222         int nleft = len;
 223         const u_short *w = addr;
 224         u_short answer;
 225         int sum = csum;
 226
 227         /*
 228          *  Our algorithm is simple, using a 32 bit accumulator (sum),
 229          *  we add sequential 16 bit words to it, and at the end, fold
 230          *  back all the carry bits from the top 16 bits into the lower
 231          *  16 bits.
 232          */
 233         while (nleft > 1)  {
 234                 sum += *w++;
 235                 nleft -= 2;
 236         }
 237         if (nleft == 1)
 238                 sum += htons(*(u_char *)w<<8);
 239
 240         /*
 241          * add back carry outs from top 16 bits to low 16 bits
 242          */
 243         sum = (sum >> 16) + (sum & 0xffff);     /* add hi 16 to low 16 */
 244         sum += (sum >> 16);                     /* add carry */
 245         answer = ~sum;                          /* truncate to 16 bits */
 246         return (answer);
 247 }
 248
 249 /*
 250  * print an IP datagram.
 251  */
 252 void
 253 ip_print(register const u_char *bp, register u_int length)
 254 {
 255         register const struct ip *ip;
 256         register u_int hlen, len, len0, off;
 257         register const u_char *cp;
 258         u_char nh;
 259         int advance;
 260
 261         ip = (const struct ip *)bp;
 262 #ifdef LBL_ALIGN
 263         /*
 264          * If the IP header is not aligned, copy into abuf.
 265          * This will never happen with BPF.  It does happen raw packet
 266          * dumps from -r.
 267          */
 268         if ((long)ip & 3) {
 269                 static u_char *abuf = NULL;
 270                 static int didwarn = 0;
 271
 272                 if (abuf == NULL) {
 273                         abuf = (u_char *)malloc(snaplen);
 274                         if (abuf == NULL)
 275                                 error("ip_print: malloc");
 276                 }
 277                 memcpy((char *)abuf, (char *)ip, min(length, snaplen));
 278                 snapend += abuf - (u_char *)ip;
 279                 packetp = abuf;
 280                 ip = (struct ip *)abuf;
 281                 /* We really want libpcap to give us aligned packets */
 282                 if (!didwarn) {
 283                         warning("compensating for unaligned libpcap packets");
 284                         ++didwarn;
 285                 }
 286         }
 287 #endif
 288         if ((u_char *)(ip + 1) > snapend) {
 289                 printf("[|ip]");
 290                 return;
 291         }
 292         if (length < sizeof (struct ip)) {
 293                 (void)printf("truncated-ip %d", length);
 294                 return;
 295         }
 296         hlen = IP_HL(ip) * 4;
 297         if (hlen < sizeof (struct ip)) {
 298                 (void)printf("bad-hlen %d", hlen);
 299                 return;
 300         }
 301
 302         len = ntohs(ip->ip_len);
 303         if (length < len)
 304                 (void)printf("truncated-ip - %d bytes missing! ",
 305                         len - length);
 306         len -= hlen;
 307         len0 = len;
 308
 309         /*
 310          * If this is fragment zero, hand it to the next higher
 311          * level protocol.
 312          */
 313         off = ntohs(ip->ip_off);
 314         if ((off & 0x1fff) == 0) {
 315                 cp = (const u_char *)ip + hlen;
 316                 nh = ip->ip_p;
 317
 318 #ifndef IPPROTO_SCTP
 319 #define IPPROTO_SCTP 132
 320 #endif
 321                 if (nh != IPPROTO_TCP && nh != IPPROTO_UDP &&
 322                     nh != IPPROTO_SCTP) {
 323                         (void)printf("%s > %s: ", ipaddr_string(&ip->ip_src),
 324                                 ipaddr_string(&ip->ip_dst));
 325                 }
 326 again:
 327                 switch (nh) {
 328
 329 #ifndef IPPROTO_AH
 330 #define IPPROTO_AH      51
 331 #endif
 332                 case IPPROTO_AH:
 333                         nh = *cp;
 334                         advance = ah_print(cp, (const u_char *)ip);
 335                         cp += advance;
 336                         len -= advance;
 337                         goto again;
 338
 339 #ifndef IPPROTO_ESP
 340 #define IPPROTO_ESP     50
 341 #endif
 342                 case IPPROTO_ESP:
 343                     {
 344                         int enh;
 345                         advance = esp_print(cp, (const u_char *)ip, &enh);
 346                         cp += advance;
 347                         len -= advance;
 348                         if (enh < 0)
 349                                 break;
 350                         nh = enh & 0xff;
 351                         goto again;
 352                     }
 353
 354 #ifndef IPPROTO_IPCOMP
 355 #define IPPROTO_IPCOMP  108
 356 #endif
 357                 case IPPROTO_IPCOMP:
 358                     {
 359                         int enh;
 360                         advance = ipcomp_print(cp, (const u_char *)ip, &enh);
 361                         cp += advance;
 362                         len -= advance;
 363                         if (enh < 0)
 364                                 break;
 365                         nh = enh & 0xff;
 366                         goto again;
 367                     }
 368
 369                 case IPPROTO_SCTP:
 370                         sctp_print(cp, (const u_char *)ip, len);
 371                         break;
 372
 373                 case IPPROTO_TCP:
 374                         tcp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
 375                         break;
 376
 377                 case IPPROTO_UDP:
 378                         udp_print(cp, len, (const u_char *)ip, (off &~ 0x6000));
 379                         break;
 380
 381                 case IPPROTO_ICMP:
 382                         icmp_print(cp, len, (const u_char *)ip);
 383                         break;
 384
 385 #ifndef IPPROTO_IGRP
 386 #define IPPROTO_IGRP 9
 387 #endif
 388                 case IPPROTO_IGRP:
 389                         igrp_print(cp, len, (const u_char *)ip);
 390                         break;
 391
 392                 case IPPROTO_ND:
 393                         (void)printf(" nd %d", len);
 394                         break;
 395
 396                 case IPPROTO_EGP:
 397                         egp_print(cp, len, (const u_char *)ip);
 398                         break;
 399
 400 #ifndef IPPROTO_OSPF
 401 #define IPPROTO_OSPF 89
 402 #endif
 403                 case IPPROTO_OSPF:
 404                         ospf_print(cp, len, (const u_char *)ip);
 405                         break;
 406
 407 #ifndef IPPROTO_IGMP
 408 #define IPPROTO_IGMP 2
 409 #endif
 410                 case IPPROTO_IGMP:
 411                         igmp_print(cp, len, (const u_char *)ip);
 412                         break;
 413
 414                 case 4:
 415                         /* DVMRP multicast tunnel (ip-in-ip encapsulation) */
 416                         ip_print(cp, len);
 417                         if (! vflag) {
 418                                 printf(" (ipip-proto-4)");
 419                                 return;
 420                         }
 421                         break;
 422
 423 #ifdef INET6
 424 #ifndef IP6PROTO_ENCAP
 425 #define IP6PROTO_ENCAP 41
 426 #endif
 427                 case IP6PROTO_ENCAP:
 428                         /* ip6-in-ip encapsulation */
 429                         ip6_print(cp, len);
 430                         break;
 431 #endif /*INET6*/
 432
 433
 434 #ifndef IPPROTO_GRE
 435 #define IPPROTO_GRE 47
 436 #endif
 437                 case IPPROTO_GRE:
 438                         /* do it */
 439                         gre_print(cp, len);
 440                         break;
 441
 442 #ifndef IPPROTO_MOBILE
 443 #define IPPROTO_MOBILE 55
 444 #endif
 445                 case IPPROTO_MOBILE:
 446                         mobile_print(cp, len);
 447                         break;
 448
 449 #ifndef IPPROTO_PIM
 450 #define IPPROTO_PIM     103
 451 #endif
 452                 case IPPROTO_PIM:
 453                         pim_print(cp, len);
 454                         break;
 455
 456 #ifndef IPPROTO_VRRP
 457 #define IPPROTO_VRRP    112
 458 #endif
 459                 case IPPROTO_VRRP:
 460                         vrrp_print(cp, len, ip->ip_ttl);
 461                         break;
 462
 463                 default:
 464                         (void)printf(" ip-proto-%d %d", nh, len);
 465                         break;
 466                 }
 467         }
 468
 469         /* Ultra quiet now means that all this stuff should be suppressed */
 470         /* res 3-Nov-98 */
 471         if (qflag > 1) return;
 472
 473
 474         /*
 475          * for fragmented datagrams, print id:size@offset.  On all
 476          * but the last stick a "+".  For unfragmented datagrams, note
 477          * the don't fragment flag.
 478          */
 479         len = len0;     /* get the original length */
 480         if (off & 0x3fff) {
 481                 /*
 482                  * if this isn't the first frag, we're missing the
 483                  * next level protocol header.  print the ip addr.
 484                  */
 485                 if (off & 0x1fff)
 486                         (void)printf("%s > %s:", ipaddr_string(&ip->ip_src),
 487                                       ipaddr_string(&ip->ip_dst));
 488 #ifndef IP_MF
 489 #define IP_MF 0x2000
 490 #endif /* IP_MF */
 491 #ifndef IP_DF
 492 #define IP_DF 0x4000
 493 #endif /* IP_DF */
 494                 (void)printf(" (frag %d:%u@%d%s)", ntohs(ip->ip_id), len,
 495                         (off & 0x1fff) * 8,
 496                         (off & IP_MF)? "+" : "");
 497
 498         } else if (off & IP_DF)
 499                 (void)printf(" (DF)");
 500
 501         if (ip->ip_tos) {
 502                 (void)printf(" [tos 0x%x", (int)ip->ip_tos);
 503                 /* ECN bits */
 504                 if (ip->ip_tos & 0x03) {
 505                         switch (ip->ip_tos & 0x03) {
 506                         case 1:
 507                                 (void)printf(",ECT(1)");
 508                                 break;
 509                         case 2:
 510                                 (void)printf(",ECT(0)");
 511                                 break;
 512                         case 3:
 513                                 (void)printf(",CE");
 514                         }
 515                 }
 516                 (void)printf("] ");
 517         }
 518
 519         if (ip->ip_ttl <= 1)
 520                 (void)printf(" [ttl %d]", (int)ip->ip_ttl);
 521
 522         if (vflag) {
 523                 int sum;
 524                 char *sep = "";
 525
 526                 printf(" (");
 527                 if (ip->ip_ttl > 1) {
 528                         (void)printf("%sttl %d", sep, (int)ip->ip_ttl);
 529                         sep = ", ";
 530                 }
 531                 if ((off & 0x3fff) == 0) {
 532                         (void)printf("%sid %d", sep, (int)ntohs(ip->ip_id));
 533                         sep = ", ";
 534                 }
 535                 (void)printf("%slen %d", sep, (int)ntohs(ip->ip_len));
 536                 sep = ", ";
 537                 if ((u_char *)ip + hlen <= snapend) {
 538                         sum = in_cksum((const u_short *)ip, hlen, 0);
 539                         if (sum != 0) {
 540                                 (void)printf("%sbad cksum %x!", sep,
 541                                              ntohs(ip->ip_sum));
 542                                 sep = ", ";
 543                         }
 544                 }
 545                 if ((hlen -= sizeof(struct ip)) > 0) {
 546                         (void)printf("%soptlen=%d", sep, hlen);
 547                         ip_optprint((u_char *)(ip + 1), hlen);
 548                 }
 549                 printf(")");
 550         }
 551 }
 552
 553 void
 554 ipN_print(register const u_char *bp, register u_int length)
 555 {
 556         struct ip *ip, hdr;
 557
 558         ip = (struct ip *)bp;
 559         if (length < 4) {
 560                 (void)printf("truncated-ip %d", length);
 561                 return;
 562         }
 563         memcpy (&hdr, (char *)ip, 4);
 564         switch (IP_V(&hdr)) {
 565         case 4:
 566                 ip_print (bp, length);
 567                 return;
 568 #ifdef INET6
 569         case 6:
 570                 ip6_print (bp, length);
 571                 return;
 572 #endif
 573         default:
 574                 (void)printf("unknown ip %d", IP_V(&hdr));
 575                 return;
 576         }
 577 }