The Tcpdump Group git mirrors - tcpdump/blob - print-tcp.c

   1 /*      $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Copyright (c) 1999-2004 The tcpdump.org project
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that: (1) source code distributions
  11  * retain the above copyright notice and this paragraph in its entirety, (2)
  12  * distributions including binary code include the above copyright notice and
  13  * this paragraph in its entirety in the documentation or other materials
  14  * provided with the distribution, and (3) all advertising materials mentioning
  15  * features or use of this software display the following acknowledgement:
  16  * ``This product includes software developed by the University of California,
  17  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  18  * the University nor the names of its contributors may be used to endorse
  19  * or promote products derived from this software without specific prior
  20  * written permission.
  21  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  24  */
  25
  26 #ifndef lint
  27 static const char rcsid[] _U_ =
  28 "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.135 2008-11-09 23:35:03 mcr Exp $ (LBL)";
  29 #else
  30 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
  31 #endif
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include "config.h"
  35 #endif
  36
  37 #include <tcpdump-stdinc.h>
  38
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42
  43 #include "interface.h"
  44 #include "addrtoname.h"
  45 #include "extract.h"
  46
  47 #include "tcp.h"
  48
  49 #include "ip.h"
  50 #ifdef INET6
  51 #include "ip6.h"
  52 #endif
  53 #include "ipproto.h"
  54 #include "rpc_auth.h"
  55 #include "rpc_msg.h"
  56
  57 #include "nameser.h"
  58
  59 #ifdef HAVE_LIBCRYPTO
  60 #include <openssl/md5.h>
  61 #include <signature.h>
  62
  63 static int tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
  64                                 const u_char *data, int length, const u_char *rcvsig);
  65 #endif
  66
  67 static void print_tcp_rst_data(register const u_char *sp, u_int length);
  68
  69 #define MAX_RST_DATA_LEN        30
  70
  71
  72 struct tha {
  73         struct in_addr src;
  74         struct in_addr dst;
  75         u_int port;
  76 };
  77
  78 struct tcp_seq_hash {
  79         struct tcp_seq_hash *nxt;
  80         struct tha addr;
  81         tcp_seq seq;
  82         tcp_seq ack;
  83 };
  84
  85 #ifdef INET6
  86 struct tha6 {
  87         struct in6_addr src;
  88         struct in6_addr dst;
  89         u_int port;
  90 };
  91
  92 struct tcp_seq_hash6 {
  93         struct tcp_seq_hash6 *nxt;
  94         struct tha6 addr;
  95         tcp_seq seq;
  96         tcp_seq ack;
  97 };
  98 #endif
  99
 100 #define TSEQ_HASHSIZE 919
 101
 102 /* These tcp optinos do not have the size octet */
 103 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 104
 105 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 106 #ifdef INET6
 107 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 108 #endif
 109
 110 static const struct tok tcp_flag_values[] = {
 111         { TH_FIN, "F" },
 112         { TH_SYN, "S" },
 113         { TH_RST, "R" },
 114         { TH_PUSH, "P" },
 115         { TH_ACK, "." },
 116         { TH_URG, "U" },
 117         { TH_ECNECHO, "E" },
 118         { TH_CWR, "W" },
 119         { 0, NULL }
 120 };
 121
 122 static const struct tok tcp_option_values[] = {
 123         { TCPOPT_EOL, "eol" },
 124         { TCPOPT_NOP, "nop" },
 125         { TCPOPT_MAXSEG, "mss" },
 126         { TCPOPT_WSCALE, "wscale" },
 127         { TCPOPT_SACKOK, "sackOK" },
 128         { TCPOPT_SACK, "sack" },
 129         { TCPOPT_ECHO, "echo" },
 130         { TCPOPT_ECHOREPLY, "echoreply" },
 131         { TCPOPT_TIMESTAMP, "TS" },
 132         { TCPOPT_CC, "cc" },
 133         { TCPOPT_CCNEW, "ccnew" },
 134         { TCPOPT_CCECHO, "" },
 135         { TCPOPT_SIGNATURE, "md5" },
 136         { TCPOPT_AUTH, "enhanced auth" },
 137         { TCPOPT_UTO, "uto" },
 138         { TCPOPT_MPTCP, "mptcp" },
 139         { TCPOPT_EXPERIMENT2, "exp" },
 140         { 0, NULL }
 141 };
 142
 143 static int tcp_cksum(register const struct ip *ip,
 144                      register const struct tcphdr *tp,
 145                      register u_int len)
 146 {
 147         return (nextproto4_cksum(ip, (const u_int8_t *)tp, len,
 148             IPPROTO_TCP));
 149 }
 150
 151 void
 152 tcp_print(register const u_char *bp, register u_int length,
 153           register const u_char *bp2, int fragmented)
 154 {
 155         register const struct tcphdr *tp;
 156         register const struct ip *ip;
 157         register u_char flags;
 158         register u_int hlen;
 159         register char ch;
 160         u_int16_t sport, dport, win, urp;
 161         u_int32_t seq, ack, thseq, thack;
 162         u_int utoval;
 163         u_int16_t magic;
 164         register int rev;
 165 #ifdef INET6
 166         register const struct ip6_hdr *ip6;
 167 #endif
 168
 169         tp = (struct tcphdr *)bp;
 170         ip = (struct ip *)bp2;
 171 #ifdef INET6
 172         if (IP_V(ip) == 6)
 173                 ip6 = (struct ip6_hdr *)bp2;
 174         else
 175                 ip6 = NULL;
 176 #endif /*INET6*/
 177         ch = '\0';
 178         if (!TTEST(tp->th_dport)) {
 179                 (void)printf("%s > %s: [|tcp]",
 180                              ipaddr_string(&ip->ip_src),
 181                              ipaddr_string(&ip->ip_dst));
 182                 return;
 183         }
 184
 185         sport = EXTRACT_16BITS(&tp->th_sport);
 186         dport = EXTRACT_16BITS(&tp->th_dport);
 187
 188         hlen = TH_OFF(tp) * 4;
 189
 190         /*
 191          * If data present, header length valid, and NFS port used,
 192          * assume NFS.
 193          * Pass offset of data plus 4 bytes for RPC TCP msg length
 194          * to NFS print routines.
 195          */
 196         if (!qflag && hlen >= sizeof(*tp) && hlen <= length &&
 197             (length - hlen) >= 4) {
 198                 u_char *fraglenp;
 199                 u_int32_t fraglen;
 200                 register struct sunrpc_msg *rp;
 201                 enum sunrpc_msg_type direction;
 202
 203                 fraglenp = (u_char *)tp + hlen;
 204                 if (TTEST2(*fraglenp, 4)) {
 205                         fraglen = EXTRACT_32BITS(fraglenp) & 0x7FFFFFFF;
 206                         if (fraglen > (length - hlen) - 4)
 207                                 fraglen = (length - hlen) - 4;
 208                         rp = (struct sunrpc_msg *)(fraglenp + 4);
 209                         if (TTEST(rp->rm_direction)) {
 210                                 direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 211                                 if (dport == NFS_PORT &&
 212                                     direction == SUNRPC_CALL) {
 213                                         nfsreq_print((u_char *)rp, fraglen,
 214                                             (u_char *)ip);
 215                                         return;
 216                                 }
 217                                 if (sport == NFS_PORT &&
 218                                     direction == SUNRPC_REPLY) {
 219                                         nfsreply_print((u_char *)rp, fraglen,
 220                                             (u_char *)ip);
 221                                         return;
 222                                 }
 223                         }
 224                 }
 225         }
 226 #ifdef INET6
 227         if (ip6) {
 228                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 229                         (void)printf("%s.%s > %s.%s: ",
 230                                      ip6addr_string(&ip6->ip6_src),
 231                                      tcpport_string(sport),
 232                                      ip6addr_string(&ip6->ip6_dst),
 233                                      tcpport_string(dport));
 234                 } else {
 235                         (void)printf("%s > %s: ",
 236                                      tcpport_string(sport), tcpport_string(dport));
 237                 }
 238         } else
 239 #endif /*INET6*/
 240         {
 241                 if (ip->ip_p == IPPROTO_TCP) {
 242                         (void)printf("%s.%s > %s.%s: ",
 243                                      ipaddr_string(&ip->ip_src),
 244                                      tcpport_string(sport),
 245                                      ipaddr_string(&ip->ip_dst),
 246                                      tcpport_string(dport));
 247                 } else {
 248                         (void)printf("%s > %s: ",
 249                                      tcpport_string(sport), tcpport_string(dport));
 250                 }
 251         }
 252
 253         if (hlen < sizeof(*tp)) {
 254                 (void)printf(" tcp %d [bad hdr length %u - too short, < %lu]",
 255                              length - hlen, hlen, (unsigned long)sizeof(*tp));
 256                 return;
 257         }
 258
 259         TCHECK(*tp);
 260
 261         seq = EXTRACT_32BITS(&tp->th_seq);
 262         ack = EXTRACT_32BITS(&tp->th_ack);
 263         win = EXTRACT_16BITS(&tp->th_win);
 264         urp = EXTRACT_16BITS(&tp->th_urp);
 265
 266         if (qflag) {
 267                 (void)printf("tcp %d", length - hlen);
 268                 if (hlen > length) {
 269                         (void)printf(" [bad hdr length %u - too long, > %u]",
 270                                      hlen, length);
 271                 }
 272                 return;
 273         }
 274
 275         flags = tp->th_flags;
 276         printf("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 277
 278         if (!Sflag && (flags & TH_ACK)) {
 279                 /*
 280                  * Find (or record) the initial sequence numbers for
 281                  * this conversation.  (we pick an arbitrary
 282                  * collating order so there's only one entry for
 283                  * both directions).
 284                  */
 285                 rev = 0;
 286 #ifdef INET6
 287                 if (ip6) {
 288                         register struct tcp_seq_hash6 *th;
 289                         struct tcp_seq_hash6 *tcp_seq_hash;
 290                         const struct in6_addr *src, *dst;
 291                         struct tha6 tha;
 292
 293                         tcp_seq_hash = tcp_seq_hash6;
 294                         src = &ip6->ip6_src;
 295                         dst = &ip6->ip6_dst;
 296                         if (sport > dport)
 297                                 rev = 1;
 298                         else if (sport == dport) {
 299                                 if (memcmp(src, dst, sizeof ip6->ip6_dst) > 0)
 300                                         rev = 1;
 301                         }
 302                         if (rev) {
 303                                 memcpy(&tha.src, dst, sizeof ip6->ip6_dst);
 304                                 memcpy(&tha.dst, src, sizeof ip6->ip6_src);
 305                                 tha.port = dport << 16 | sport;
 306                         } else {
 307                                 memcpy(&tha.dst, dst, sizeof ip6->ip6_dst);
 308                                 memcpy(&tha.src, src, sizeof ip6->ip6_src);
 309                                 tha.port = sport << 16 | dport;
 310                         }
 311
 312                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 313                              th->nxt; th = th->nxt)
 314                                 if (memcmp((char *)&tha, (char *)&th->addr,
 315                                            sizeof(th->addr)) == 0)
 316                                         break;
 317
 318                         if (!th->nxt || (flags & TH_SYN)) {
 319                                 /* didn't find it or new conversation */
 320                                 if (th->nxt == NULL) {
 321                                         th->nxt = (struct tcp_seq_hash6 *)
 322                                                 calloc(1, sizeof(*th));
 323                                         if (th->nxt == NULL)
 324                                                 error("tcp_print: calloc");
 325                                 }
 326                                 th->addr = tha;
 327                                 if (rev)
 328                                         th->ack = seq, th->seq = ack - 1;
 329                                 else
 330                                         th->seq = seq, th->ack = ack - 1;
 331                         } else {
 332                                 if (rev)
 333                                         seq -= th->ack, ack -= th->seq;
 334                                 else
 335                                         seq -= th->seq, ack -= th->ack;
 336                         }
 337
 338                         thseq = th->seq;
 339                         thack = th->ack;
 340                 } else {
 341 #else  /*INET6*/
 342                 {
 343 #endif /*INET6*/
 344                         register struct tcp_seq_hash *th;
 345                         struct tcp_seq_hash *tcp_seq_hash;
 346                         const struct in_addr *src, *dst;
 347                         struct tha tha;
 348
 349                         tcp_seq_hash = tcp_seq_hash4;
 350                         src = &ip->ip_src;
 351                         dst = &ip->ip_dst;
 352                         if (sport > dport)
 353                                 rev = 1;
 354                         else if (sport == dport) {
 355                                 if (memcmp(src, dst, sizeof ip->ip_dst) > 0)
 356                                         rev = 1;
 357                         }
 358                         if (rev) {
 359                                 memcpy(&tha.src, dst, sizeof ip->ip_dst);
 360                                 memcpy(&tha.dst, src, sizeof ip->ip_src);
 361                                 tha.port = dport << 16 | sport;
 362                         } else {
 363                                 memcpy(&tha.dst, dst, sizeof ip->ip_dst);
 364                                 memcpy(&tha.src, src, sizeof ip->ip_src);
 365                                 tha.port = sport << 16 | dport;
 366                         }
 367
 368                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 369                              th->nxt; th = th->nxt)
 370                                 if (memcmp((char *)&tha, (char *)&th->addr,
 371                                            sizeof(th->addr)) == 0)
 372                                         break;
 373
 374                         if (!th->nxt || (flags & TH_SYN)) {
 375                                 /* didn't find it or new conversation */
 376                                 if (th->nxt == NULL) {
 377                                         th->nxt = (struct tcp_seq_hash *)
 378                                                 calloc(1, sizeof(*th));
 379                                         if (th->nxt == NULL)
 380                                                 error("tcp_print: calloc");
 381                                 }
 382                                 th->addr = tha;
 383                                 if (rev)
 384                                         th->ack = seq, th->seq = ack - 1;
 385                                 else
 386                                         th->seq = seq, th->ack = ack - 1;
 387                         } else {
 388                                 if (rev)
 389                                         seq -= th->ack, ack -= th->seq;
 390                                 else
 391                                         seq -= th->seq, ack -= th->ack;
 392                         }
 393
 394                         thseq = th->seq;
 395                         thack = th->ack;
 396                 }
 397         } else {
 398                 /*fool gcc*/
 399                 thseq = thack = rev = 0;
 400         }
 401         if (hlen > length) {
 402                 (void)printf(" [bad hdr length %u - too long, > %u]",
 403                              hlen, length);
 404                 return;
 405         }
 406
 407         if (vflag && !Kflag && !fragmented) {
 408                 /* Check the checksum, if possible. */
 409                 u_int16_t sum, tcp_sum;
 410
 411                 if (IP_V(ip) == 4) {
 412                         if (TTEST2(tp->th_sport, length)) {
 413                                 sum = tcp_cksum(ip, tp, length);
 414                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 415
 416                                 (void)printf(", cksum 0x%04x", tcp_sum);
 417                                 if (sum != 0)
 418                                         (void)printf(" (incorrect -> 0x%04x)",
 419                                             in_cksum_shouldbe(tcp_sum, sum));
 420                                 else
 421                                         (void)printf(" (correct)");
 422                         }
 423                 }
 424 #ifdef INET6
 425                 else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 426                         if (TTEST2(tp->th_sport, length)) {
 427                                 sum = nextproto6_cksum(ip6, (const u_int8_t *)tp, length, IPPROTO_TCP);
 428                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 429
 430                                 (void)printf(", cksum 0x%04x", tcp_sum);
 431                                 if (sum != 0)
 432                                         (void)printf(" (incorrect -> 0x%04x)",
 433                                             in_cksum_shouldbe(tcp_sum, sum));
 434                                 else
 435                                         (void)printf(" (correct)");
 436
 437                         }
 438                 }
 439 #endif
 440         }
 441
 442         length -= hlen;
 443         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 444                 (void)printf(", seq %u", seq);
 445
 446                 if (length > 0) {
 447                         (void)printf(":%u", seq + length);
 448                 }
 449         }
 450
 451         if (flags & TH_ACK) {
 452                 (void)printf(", ack %u", ack);
 453         }
 454
 455         (void)printf(", win %d", win);
 456
 457         if (flags & TH_URG)
 458                 (void)printf(", urg %d", urp);
 459         /*
 460          * Handle any options.
 461          */
 462         if (hlen > sizeof(*tp)) {
 463                 register const u_char *cp;
 464                 register u_int i, opt, datalen;
 465                 register u_int len;
 466
 467                 hlen -= sizeof(*tp);
 468                 cp = (const u_char *)tp + sizeof(*tp);
 469                 printf(", options [");
 470                 while (hlen > 0) {
 471                         if (ch != '\0')
 472                                 putchar(ch);
 473                         TCHECK(*cp);
 474                         opt = *cp++;
 475                         if (ZEROLENOPT(opt))
 476                                 len = 1;
 477                         else {
 478                                 TCHECK(*cp);
 479                                 len = *cp++;    /* total including type, len */
 480                                 if (len < 2 || len > hlen)
 481                                         goto bad;
 482                                 --hlen;         /* account for length byte */
 483                         }
 484                         --hlen;                 /* account for type byte */
 485                         datalen = 0;
 486
 487 /* Bail if "l" bytes of data are not left or were not captured  */
 488 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 489
 490
 491                         printf("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 492
 493                         switch (opt) {
 494
 495                         case TCPOPT_MAXSEG:
 496                                 datalen = 2;
 497                                 LENCHECK(datalen);
 498                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 499                                 break;
 500
 501                         case TCPOPT_WSCALE:
 502                                 datalen = 1;
 503                                 LENCHECK(datalen);
 504                                 (void)printf(" %u", *cp);
 505                                 break;
 506
 507                         case TCPOPT_SACK:
 508                                 datalen = len - 2;
 509                                 if (datalen % 8 != 0) {
 510                                         (void)printf("malformed sack");
 511                                 } else {
 512                                         u_int32_t s, e;
 513
 514                                         (void)printf(" %d ", datalen / 8);
 515                                         for (i = 0; i < datalen; i += 8) {
 516                                                 LENCHECK(i + 4);
 517                                                 s = EXTRACT_32BITS(cp + i);
 518                                                 LENCHECK(i + 8);
 519                                                 e = EXTRACT_32BITS(cp + i + 4);
 520                                                 if (rev) {
 521                                                         s -= thseq;
 522                                                         e -= thseq;
 523                                                 } else {
 524                                                         s -= thack;
 525                                                         e -= thack;
 526                                                 }
 527                                                 (void)printf("{%u:%u}", s, e);
 528                                         }
 529                                 }
 530                                 break;
 531
 532                         case TCPOPT_CC:
 533                         case TCPOPT_CCNEW:
 534                         case TCPOPT_CCECHO:
 535                         case TCPOPT_ECHO:
 536                         case TCPOPT_ECHOREPLY:
 537
 538                                 /*
 539                                  * those options share their semantics.
 540                                  * fall through
 541                                  */
 542                                 datalen = 4;
 543                                 LENCHECK(datalen);
 544                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 545                                 break;
 546
 547                         case TCPOPT_TIMESTAMP:
 548                                 datalen = 8;
 549                                 LENCHECK(datalen);
 550                                 (void)printf(" val %u ecr %u",
 551                                              EXTRACT_32BITS(cp),
 552                                              EXTRACT_32BITS(cp + 4));
 553                                 break;
 554
 555                         case TCPOPT_SIGNATURE:
 556                                 datalen = TCP_SIGLEN;
 557                                 LENCHECK(datalen);
 558 #ifdef HAVE_LIBCRYPTO
 559                                 switch (tcp_verify_signature(ip, tp,
 560                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 561
 562                                 case SIGNATURE_VALID:
 563                                         (void)printf("valid");
 564                                         break;
 565
 566                                 case SIGNATURE_INVALID:
 567                                         (void)printf("invalid");
 568                                         break;
 569
 570                                 case CANT_CHECK_SIGNATURE:
 571                                         (void)printf("can't check - ");
 572                                         for (i = 0; i < TCP_SIGLEN; ++i)
 573                                                 (void)printf("%02x", cp[i]);
 574                                         break;
 575                                 }
 576 #else
 577                                 for (i = 0; i < TCP_SIGLEN; ++i)
 578                                         (void)printf("%02x", cp[i]);
 579 #endif
 580                                 break;
 581
 582                         case TCPOPT_AUTH:
 583                                 (void)printf("keyid %d", *cp++);
 584                                 datalen = len - 3;
 585                                 for (i = 0; i < datalen; ++i) {
 586                                         LENCHECK(i);
 587                                         (void)printf("%02x", cp[i]);
 588                                 }
 589                                 break;
 590
 591
 592                         case TCPOPT_EOL:
 593                         case TCPOPT_NOP:
 594                         case TCPOPT_SACKOK:
 595                                 /*
 596                                  * Nothing interesting.
 597                                  * fall through
 598                                  */
 599                                 break;
 600
 601                         case TCPOPT_UTO:
 602                                 datalen = 2;
 603                                 LENCHECK(datalen);
 604                                 utoval = EXTRACT_16BITS(cp);
 605                                 (void)printf("0x%x", utoval);
 606                                 if (utoval & 0x0001)
 607                                         utoval = (utoval >> 1) * 60;
 608                                 else
 609                                         utoval >>= 1;
 610                                 (void)printf(" %u", utoval);
 611                                 break;
 612
 613                         case TCPOPT_MPTCP:
 614                                 datalen = len - 2;
 615                                 LENCHECK(datalen);
 616                                 if (!mptcp_print(cp-2, len, flags))
 617                                         goto bad;
 618                                 break;
 619
 620                         case TCPOPT_EXPERIMENT2:
 621                                 datalen = len - 2;
 622                                 LENCHECK(datalen);
 623                                 if (datalen < 2)
 624                                         goto bad;
 625                                 /* RFC6994 */
 626                                 magic = EXTRACT_16BITS(cp);
 627                                 (void)printf("-");
 628
 629                                 switch(magic) {
 630
 631                                 case 0xf989:
 632                                         /* TCP Fast Open: draft-ietf-tcpm-fastopen-04 */
 633                                         if (datalen == 2) {
 634                                                 /* Fast Open Cookie Request */
 635                                                 (void)printf("tfo cookiereq");
 636                                         } else {
 637                                                 /* Fast Open Cookie */
 638                                                 if (datalen % 2 != 0 || datalen < 6 || datalen > 18) {
 639                                                         (void)printf("tfo malformed");
 640                                                 } else {
 641                                                         (void)printf("tfo cookie ");
 642                                                         for (i = 2; i < datalen; ++i)
 643                                                                 (void)printf("%02x", cp[i]);
 644                                                 }
 645                                         }
 646                                         break;
 647
 648                                 default:
 649                                         /* Unknown magic number */
 650                                         (void)printf("%04x", magic);
 651                                         break;
 652                                 }
 653                                 break;
 654
 655                         default:
 656                                 datalen = len - 2;
 657                                 if (datalen)
 658                                         printf(" 0x");
 659                                 for (i = 0; i < datalen; ++i) {
 660                                         LENCHECK(i);
 661                                         (void)printf("%02x", cp[i]);
 662                                 }
 663                                 break;
 664                         }
 665
 666                         /* Account for data printed */
 667                         cp += datalen;
 668                         hlen -= datalen;
 669
 670                         /* Check specification against observed length */
 671                         ++datalen;                      /* option octet */
 672                         if (!ZEROLENOPT(opt))
 673                                 ++datalen;              /* size octet */
 674                         if (datalen != len)
 675                                 (void)printf("[len %d]", len);
 676                         ch = ',';
 677                         if (opt == TCPOPT_EOL)
 678                                 break;
 679                 }
 680                 putchar(']');
 681         }
 682
 683         /*
 684          * Print length field before crawling down the stack.
 685          */
 686         printf(", length %u", length);
 687
 688         if (length <= 0)
 689                 return;
 690
 691         /*
 692          * Decode payload if necessary.
 693          */
 694         bp += TH_OFF(tp) * 4;
 695         if ((flags & TH_RST) && vflag) {
 696                 print_tcp_rst_data(bp, length);
 697                 return;
 698         }
 699
 700         if (packettype) {
 701                 switch (packettype) {
 702                 case PT_ZMTP1:
 703                         zmtp1_print(bp, length);
 704                         break;
 705                 }
 706                 return;
 707         }
 708
 709         if (sport == TELNET_PORT || dport == TELNET_PORT) {
 710                 if (!qflag && vflag)
 711                         telnet_print(bp, length);
 712         } else if (sport == BGP_PORT || dport == BGP_PORT)
 713                 bgp_print(bp, length);
 714         else if (sport == PPTP_PORT || dport == PPTP_PORT)
 715                 pptp_print(bp);
 716 #ifdef TCPDUMP_DO_SMB
 717         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 718                 nbt_tcp_print(bp, length);
 719         else if (sport == SMB_PORT || dport == SMB_PORT)
 720                 smb_tcp_print(bp, length);
 721 #endif
 722         else if (sport == BEEP_PORT || dport == BEEP_PORT)
 723                 beep_print(bp, length);
 724         else if (sport == OPENFLOW_PORT || dport == OPENFLOW_PORT)
 725                 openflow_print(bp, length);
 726         else if (length > 2 &&
 727                  (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT ||
 728                   sport == MULTICASTDNS_PORT || dport == MULTICASTDNS_PORT)) {
 729                 /*
 730                  * TCP DNS query has 2byte length at the head.
 731                  * XXX packet could be unaligned, it can go strange
 732                  */
 733                 ns_print(bp + 2, length - 2, 0);
 734         } else if (sport == MSDP_PORT || dport == MSDP_PORT) {
 735                 msdp_print(bp, length);
 736         } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) {
 737                 rpki_rtr_print(bp, length);
 738         }
 739         else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) {
 740                 ldp_print(bp, length);
 741         }
 742
 743         return;
 744  bad:
 745         fputs("[bad opt]", stdout);
 746         if (ch != '\0')
 747                 putchar('>');
 748         return;
 749  trunc:
 750         fputs("[|tcp]", stdout);
 751         if (ch != '\0')
 752                 putchar('>');
 753 }
 754
 755 /*
 756  * RFC1122 says the following on data in RST segments:
 757  *
 758  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 759  *
 760  *            A TCP SHOULD allow a received RST segment to include data.
 761  *
 762  *            DISCUSSION
 763  *                 It has been suggested that a RST segment could contain
 764  *                 ASCII text that encoded and explained the cause of the
 765  *                 RST.  No standard has yet been established for such
 766  *                 data.
 767  *
 768  */
 769
 770 static void
 771 print_tcp_rst_data(register const u_char *sp, u_int length)
 772 {
 773         int c;
 774
 775         if (TTEST2(*sp, length))
 776                 printf(" [RST");
 777         else
 778                 printf(" [!RST");
 779         if (length > MAX_RST_DATA_LEN) {
 780                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 781                 putchar('+');                   /* indicate we truncate */
 782         }
 783         putchar(' ');
 784         while (length-- && sp <= snapend) {
 785                 c = *sp++;
 786                 safeputchar(c);
 787         }
 788         putchar(']');
 789 }
 790
 791 #ifdef HAVE_LIBCRYPTO
 792 USES_APPLE_DEPRECATED_API
 793 static int
 794 tcp_verify_signature(const struct ip *ip, const struct tcphdr *tp,
 795                      const u_char *data, int length, const u_char *rcvsig)
 796 {
 797         struct tcphdr tp1;
 798         u_char sig[TCP_SIGLEN];
 799         char zero_proto = 0;
 800         MD5_CTX ctx;
 801         u_int16_t savecsum, tlen;
 802 #ifdef INET6
 803         struct ip6_hdr *ip6;
 804         u_int32_t len32;
 805         u_int8_t nxt;
 806 #endif
 807
 808         if (data + length > snapend) {
 809                 printf("snaplen too short, ");
 810                 return (CANT_CHECK_SIGNATURE);
 811         }
 812
 813         tp1 = *tp;
 814
 815         if (sigsecret == NULL) {
 816                 printf("shared secret not supplied with -M, ");
 817                 return (CANT_CHECK_SIGNATURE);
 818         }
 819
 820         MD5_Init(&ctx);
 821         /*
 822          * Step 1: Update MD5 hash with IP pseudo-header.
 823          */
 824         if (IP_V(ip) == 4) {
 825                 MD5_Update(&ctx, (char *)&ip->ip_src, sizeof(ip->ip_src));
 826                 MD5_Update(&ctx, (char *)&ip->ip_dst, sizeof(ip->ip_dst));
 827                 MD5_Update(&ctx, (char *)&zero_proto, sizeof(zero_proto));
 828                 MD5_Update(&ctx, (char *)&ip->ip_p, sizeof(ip->ip_p));
 829                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 830                 tlen = htons(tlen);
 831                 MD5_Update(&ctx, (char *)&tlen, sizeof(tlen));
 832 #ifdef INET6
 833         } else if (IP_V(ip) == 6) {
 834                 ip6 = (struct ip6_hdr *)ip;
 835                 MD5_Update(&ctx, (char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 836                 MD5_Update(&ctx, (char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 837                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 838                 MD5_Update(&ctx, (char *)&len32, sizeof(len32));
 839                 nxt = 0;
 840                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
 841                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
 842                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
 843                 nxt = IPPROTO_TCP;
 844                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
 845 #endif
 846         } else {
 847 #ifdef INET6
 848                 printf("IP version not 4 or 6, ");
 849 #else
 850                 printf("IP version not 4, ");
 851 #endif
 852                 return (CANT_CHECK_SIGNATURE);
 853         }
 854
 855         /*
 856          * Step 2: Update MD5 hash with TCP header, excluding options.
 857          * The TCP checksum must be set to zero.
 858          */
 859         savecsum = tp1.th_sum;
 860         tp1.th_sum = 0;
 861         MD5_Update(&ctx, (char *)&tp1, sizeof(struct tcphdr));
 862         tp1.th_sum = savecsum;
 863         /*
 864          * Step 3: Update MD5 hash with TCP segment data, if present.
 865          */
 866         if (length > 0)
 867                 MD5_Update(&ctx, data, length);
 868         /*
 869          * Step 4: Update MD5 hash with shared secret.
 870          */
 871         MD5_Update(&ctx, sigsecret, strlen(sigsecret));
 872         MD5_Final(sig, &ctx);
 873
 874         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 875                 return (SIGNATURE_VALID);
 876         else
 877                 return (SIGNATURE_INVALID);
 878 }
 879 USES_APPLE_RST
 880 #endif /* HAVE_LIBCRYPTO */
 881
 882 /*
 883  * Local Variables:
 884  * c-style: whitesmith
 885  * c-basic-offset: 8
 886  * End:
 887  */