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