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 <stdlib.h>
  38 #include <string.h>
  39
  40 #include "interface.h"
  41 #include "addrtoname.h"
  42 #include "extract.h"
  43
  44 #include "tcp.h"
  45
  46 #include "ip.h"
  47 #ifdef INET6
  48 #include "ip6.h"
  49 #endif
  50 #include "ipproto.h"
  51 #include "rpc_auth.h"
  52 #include "rpc_msg.h"
  53
  54 #include "nameser.h"
  55
  56 #ifdef HAVE_LIBCRYPTO
  57 #include <openssl/md5.h>
  58 #include <signature.h>
  59
  60 static int tcp_verify_signature(netdissect_options *ndo,
  61                                 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(netdissect_options *, register const u_char *sp, u_int length);
  66 static void print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
  67                                       u_int datalen, int exp);
  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_FASTOPEN, "tfo" },
 140         { TCPOPT_EXPERIMENT2, "exp" },
 141         { 0, NULL }
 142 };
 143
 144 static int
 145 tcp_cksum(netdissect_options *ndo,
 146           register const struct ip *ip,
 147           register const struct tcphdr *tp,
 148           register u_int len)
 149 {
 150         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 151                                 IPPROTO_TCP);
 152 }
 153
 154 void
 155 tcp_print(netdissect_options *ndo,
 156           register const u_char *bp, register u_int length,
 157           register const u_char *bp2, int fragmented)
 158 {
 159         register const struct tcphdr *tp;
 160         register const struct ip *ip;
 161         register u_char flags;
 162         register u_int hlen;
 163         register char ch;
 164         uint16_t sport, dport, win, urp;
 165         uint32_t seq, ack, thseq, thack;
 166         u_int utoval;
 167         uint16_t magic;
 168         register int rev;
 169 #ifdef INET6
 170         register const struct ip6_hdr *ip6;
 171 #endif
 172
 173         tp = (const struct tcphdr *)bp;
 174         ip = (const struct ip *)bp2;
 175 #ifdef INET6
 176         if (IP_V(ip) == 6)
 177                 ip6 = (const struct ip6_hdr *)bp2;
 178         else
 179                 ip6 = NULL;
 180 #endif /*INET6*/
 181         ch = '\0';
 182         if (!ND_TTEST(tp->th_dport)) {
 183                 ND_PRINT((ndo, "%s > %s: [|tcp]",
 184                              ipaddr_string(ndo, &ip->ip_src),
 185                              ipaddr_string(ndo, &ip->ip_dst)));
 186                 return;
 187         }
 188
 189         sport = EXTRACT_16BITS(&tp->th_sport);
 190         dport = EXTRACT_16BITS(&tp->th_dport);
 191
 192         hlen = TH_OFF(tp) * 4;
 193
 194 #ifdef INET6
 195         if (ip6) {
 196                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 197                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 198                                      ip6addr_string(ndo, &ip6->ip6_src),
 199                                      tcpport_string(sport),
 200                                      ip6addr_string(ndo, &ip6->ip6_dst),
 201                                      tcpport_string(dport)));
 202                 } else {
 203                         ND_PRINT((ndo, "%s > %s: ",
 204                                      tcpport_string(sport), tcpport_string(dport)));
 205                 }
 206         } else
 207 #endif /*INET6*/
 208         {
 209                 if (ip->ip_p == IPPROTO_TCP) {
 210                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 211                                      ipaddr_string(ndo, &ip->ip_src),
 212                                      tcpport_string(sport),
 213                                      ipaddr_string(ndo, &ip->ip_dst),
 214                                      tcpport_string(dport)));
 215                 } else {
 216                         ND_PRINT((ndo, "%s > %s: ",
 217                                      tcpport_string(sport), tcpport_string(dport)));
 218                 }
 219         }
 220
 221         if (hlen < sizeof(*tp)) {
 222                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 223                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 224                 return;
 225         }
 226
 227         ND_TCHECK(*tp);
 228
 229         seq = EXTRACT_32BITS(&tp->th_seq);
 230         ack = EXTRACT_32BITS(&tp->th_ack);
 231         win = EXTRACT_16BITS(&tp->th_win);
 232         urp = EXTRACT_16BITS(&tp->th_urp);
 233
 234         if (ndo->ndo_qflag) {
 235                 ND_PRINT((ndo, "tcp %d", length - hlen));
 236                 if (hlen > length) {
 237                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 238                                      hlen, length));
 239                 }
 240                 return;
 241         }
 242
 243         flags = tp->th_flags;
 244         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
 245
 246         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 247                 /*
 248                  * Find (or record) the initial sequence numbers for
 249                  * this conversation.  (we pick an arbitrary
 250                  * collating order so there's only one entry for
 251                  * both directions).
 252                  */
 253                 rev = 0;
 254 #ifdef INET6
 255                 if (ip6) {
 256                         register struct tcp_seq_hash6 *th;
 257                         struct tcp_seq_hash6 *tcp_seq_hash;
 258                         const struct in6_addr *src, *dst;
 259                         struct tha6 tha;
 260
 261                         tcp_seq_hash = tcp_seq_hash6;
 262                         src = &ip6->ip6_src;
 263                         dst = &ip6->ip6_dst;
 264                         if (sport > dport)
 265                                 rev = 1;
 266                         else if (sport == dport) {
 267                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 268                                         rev = 1;
 269                         }
 270                         if (rev) {
 271                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 272                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 273                                 tha.port = dport << 16 | sport;
 274                         } else {
 275                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 276                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 277                                 tha.port = sport << 16 | dport;
 278                         }
 279
 280                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 281                              th->nxt; th = th->nxt)
 282                                 if (memcmp((char *)&tha, (char *)&th->addr,
 283                                            sizeof(th->addr)) == 0)
 284                                         break;
 285
 286                         if (!th->nxt || (flags & TH_SYN)) {
 287                                 /* didn't find it or new conversation */
 288                                 if (th->nxt == NULL) {
 289                                         th->nxt = (struct tcp_seq_hash6 *)
 290                                                 calloc(1, sizeof(*th));
 291                                         if (th->nxt == NULL)
 292                                                 error("tcp_print: calloc");
 293                                 }
 294                                 th->addr = tha;
 295                                 if (rev)
 296                                         th->ack = seq, th->seq = ack - 1;
 297                                 else
 298                                         th->seq = seq, th->ack = ack - 1;
 299                         } else {
 300                                 if (rev)
 301                                         seq -= th->ack, ack -= th->seq;
 302                                 else
 303                                         seq -= th->seq, ack -= th->ack;
 304                         }
 305
 306                         thseq = th->seq;
 307                         thack = th->ack;
 308                 } else {
 309 #else  /*INET6*/
 310                 {
 311 #endif /*INET6*/
 312                         register struct tcp_seq_hash *th;
 313                         struct tcp_seq_hash *tcp_seq_hash;
 314                         const struct in_addr *src, *dst;
 315                         struct tha tha;
 316
 317                         tcp_seq_hash = tcp_seq_hash4;
 318                         src = &ip->ip_src;
 319                         dst = &ip->ip_dst;
 320                         if (sport > dport)
 321                                 rev = 1;
 322                         else if (sport == dport) {
 323                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip->ip_dst) > 0)
 324                                         rev = 1;
 325                         }
 326                         if (rev) {
 327                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip->ip_dst);
 328                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip->ip_src);
 329                                 tha.port = dport << 16 | sport;
 330                         } else {
 331                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip->ip_dst);
 332                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip->ip_src);
 333                                 tha.port = sport << 16 | dport;
 334                         }
 335
 336                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 337                              th->nxt; th = th->nxt)
 338                                 if (memcmp((char *)&tha, (char *)&th->addr,
 339                                            sizeof(th->addr)) == 0)
 340                                         break;
 341
 342                         if (!th->nxt || (flags & TH_SYN)) {
 343                                 /* didn't find it or new conversation */
 344                                 if (th->nxt == NULL) {
 345                                         th->nxt = (struct tcp_seq_hash *)
 346                                                 calloc(1, sizeof(*th));
 347                                         if (th->nxt == NULL)
 348                                                 error("tcp_print: calloc");
 349                                 }
 350                                 th->addr = tha;
 351                                 if (rev)
 352                                         th->ack = seq, th->seq = ack - 1;
 353                                 else
 354                                         th->seq = seq, th->ack = ack - 1;
 355                         } else {
 356                                 if (rev)
 357                                         seq -= th->ack, ack -= th->seq;
 358                                 else
 359                                         seq -= th->seq, ack -= th->ack;
 360                         }
 361
 362                         thseq = th->seq;
 363                         thack = th->ack;
 364                 }
 365         } else {
 366                 /*fool gcc*/
 367                 thseq = thack = rev = 0;
 368         }
 369         if (hlen > length) {
 370                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 371                              hlen, length));
 372                 return;
 373         }
 374
 375         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 376                 /* Check the checksum, if possible. */
 377                 uint16_t sum, tcp_sum;
 378
 379                 if (IP_V(ip) == 4) {
 380                         if (ND_TTEST2(tp->th_sport, length)) {
 381                                 sum = tcp_cksum(ndo, ip, tp, length);
 382                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 383
 384                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 385                                 if (sum != 0)
 386                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 387                                             in_cksum_shouldbe(tcp_sum, sum)));
 388                                 else
 389                                         ND_PRINT((ndo, " (correct)"));
 390                         }
 391                 }
 392 #ifdef INET6
 393                 else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 394                         if (ND_TTEST2(tp->th_sport, length)) {
 395                                 sum = nextproto6_cksum(ip6, (const uint8_t *)tp,
 396                                                         length, length, IPPROTO_TCP);
 397                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 398
 399                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 400                                 if (sum != 0)
 401                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 402                                             in_cksum_shouldbe(tcp_sum, sum)));
 403                                 else
 404                                         ND_PRINT((ndo, " (correct)"));
 405
 406                         }
 407                 }
 408 #endif
 409         }
 410
 411         length -= hlen;
 412         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 413                 ND_PRINT((ndo, ", seq %u", seq));
 414
 415                 if (length > 0) {
 416                         ND_PRINT((ndo, ":%u", seq + length));
 417                 }
 418         }
 419
 420         if (flags & TH_ACK) {
 421                 ND_PRINT((ndo, ", ack %u", ack));
 422         }
 423
 424         ND_PRINT((ndo, ", win %d", win));
 425
 426         if (flags & TH_URG)
 427                 ND_PRINT((ndo, ", urg %d", urp));
 428         /*
 429          * Handle any options.
 430          */
 431         if (hlen > sizeof(*tp)) {
 432                 register const u_char *cp;
 433                 register u_int i, opt, datalen;
 434                 register u_int len;
 435
 436                 hlen -= sizeof(*tp);
 437                 cp = (const u_char *)tp + sizeof(*tp);
 438                 ND_PRINT((ndo, ", options ["));
 439                 while (hlen > 0) {
 440                         if (ch != '\0')
 441                                 ND_PRINT((ndo, "%c", ch));
 442                         ND_TCHECK(*cp);
 443                         opt = *cp++;
 444                         if (ZEROLENOPT(opt))
 445                                 len = 1;
 446                         else {
 447                                 ND_TCHECK(*cp);
 448                                 len = *cp++;    /* total including type, len */
 449                                 if (len < 2 || len > hlen)
 450                                         goto bad;
 451                                 --hlen;         /* account for length byte */
 452                         }
 453                         --hlen;                 /* account for type byte */
 454                         datalen = 0;
 455
 456 /* Bail if "l" bytes of data are not left or were not captured  */
 457 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 458
 459
 460                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 461
 462                         switch (opt) {
 463
 464                         case TCPOPT_MAXSEG:
 465                                 datalen = 2;
 466                                 LENCHECK(datalen);
 467                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 468                                 break;
 469
 470                         case TCPOPT_WSCALE:
 471                                 datalen = 1;
 472                                 LENCHECK(datalen);
 473                                 ND_PRINT((ndo, " %u", *cp));
 474                                 break;
 475
 476                         case TCPOPT_SACK:
 477                                 datalen = len - 2;
 478                                 if (datalen % 8 != 0) {
 479                                         ND_PRINT((ndo, "malformed sack"));
 480                                 } else {
 481                                         uint32_t s, e;
 482
 483                                         ND_PRINT((ndo, " %d ", datalen / 8));
 484                                         for (i = 0; i < datalen; i += 8) {
 485                                                 LENCHECK(i + 4);
 486                                                 s = EXTRACT_32BITS(cp + i);
 487                                                 LENCHECK(i + 8);
 488                                                 e = EXTRACT_32BITS(cp + i + 4);
 489                                                 if (rev) {
 490                                                         s -= thseq;
 491                                                         e -= thseq;
 492                                                 } else {
 493                                                         s -= thack;
 494                                                         e -= thack;
 495                                                 }
 496                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 497                                         }
 498                                 }
 499                                 break;
 500
 501                         case TCPOPT_CC:
 502                         case TCPOPT_CCNEW:
 503                         case TCPOPT_CCECHO:
 504                         case TCPOPT_ECHO:
 505                         case TCPOPT_ECHOREPLY:
 506
 507                                 /*
 508                                  * those options share their semantics.
 509                                  * fall through
 510                                  */
 511                                 datalen = 4;
 512                                 LENCHECK(datalen);
 513                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 514                                 break;
 515
 516                         case TCPOPT_TIMESTAMP:
 517                                 datalen = 8;
 518                                 LENCHECK(datalen);
 519                                 ND_PRINT((ndo, " val %u ecr %u",
 520                                              EXTRACT_32BITS(cp),
 521                                              EXTRACT_32BITS(cp + 4)));
 522                                 break;
 523
 524                         case TCPOPT_SIGNATURE:
 525                                 datalen = TCP_SIGLEN;
 526                                 LENCHECK(datalen);
 527 #ifdef HAVE_LIBCRYPTO
 528                                 switch (tcp_verify_signature(ndo, ip, tp,
 529                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 530
 531                                 case SIGNATURE_VALID:
 532                                         ND_PRINT((ndo, "valid"));
 533                                         break;
 534
 535                                 case SIGNATURE_INVALID:
 536                                         ND_PRINT((ndo, "invalid"));
 537                                         break;
 538
 539                                 case CANT_CHECK_SIGNATURE:
 540                                         ND_PRINT((ndo, "can't check - "));
 541                                         for (i = 0; i < TCP_SIGLEN; ++i)
 542                                                 ND_PRINT((ndo, "%02x", cp[i]));
 543                                         break;
 544                                 }
 545 #else
 546                                 for (i = 0; i < TCP_SIGLEN; ++i)
 547                                         ND_PRINT((ndo, "%02x", cp[i]));
 548 #endif
 549                                 break;
 550
 551                         case TCPOPT_AUTH:
 552                                 ND_PRINT((ndo, "keyid %d", *cp++));
 553                                 datalen = len - 3;
 554                                 for (i = 0; i < datalen; ++i) {
 555                                         LENCHECK(i);
 556                                         ND_PRINT((ndo, "%02x", cp[i]));
 557                                 }
 558                                 break;
 559
 560
 561                         case TCPOPT_EOL:
 562                         case TCPOPT_NOP:
 563                         case TCPOPT_SACKOK:
 564                                 /*
 565                                  * Nothing interesting.
 566                                  * fall through
 567                                  */
 568                                 break;
 569
 570                         case TCPOPT_UTO:
 571                                 datalen = 2;
 572                                 LENCHECK(datalen);
 573                                 utoval = EXTRACT_16BITS(cp);
 574                                 ND_PRINT((ndo, "0x%x", utoval));
 575                                 if (utoval & 0x0001)
 576                                         utoval = (utoval >> 1) * 60;
 577                                 else
 578                                         utoval >>= 1;
 579                                 ND_PRINT((ndo, " %u", utoval));
 580                                 break;
 581
 582                         case TCPOPT_MPTCP:
 583                                 datalen = len - 2;
 584                                 LENCHECK(datalen);
 585                                 if (!mptcp_print(ndo, cp-2, len, flags))
 586                                         goto bad;
 587                                 break;
 588
 589                         case TCPOPT_FASTOPEN:
 590                                 datalen = len - 2;
 591                                 LENCHECK(datalen);
 592                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 593                                 break;
 594
 595                         case TCPOPT_EXPERIMENT2:
 596                                 datalen = len - 2;
 597                                 LENCHECK(datalen);
 598                                 if (datalen < 2)
 599                                         goto bad;
 600                                 /* RFC6994 */
 601                                 magic = EXTRACT_16BITS(cp);
 602                                 ND_PRINT((ndo, "-"));
 603
 604                                 switch(magic) {
 605
 606                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 607                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 608                                         break;
 609
 610                                 default:
 611                                         /* Unknown magic number */
 612                                         ND_PRINT((ndo, "%04x", magic));
 613                                         break;
 614                                 }
 615                                 break;
 616
 617                         default:
 618                                 datalen = len - 2;
 619                                 if (datalen)
 620                                         ND_PRINT((ndo, " 0x"));
 621                                 for (i = 0; i < datalen; ++i) {
 622                                         LENCHECK(i);
 623                                         ND_PRINT((ndo, "%02x", cp[i]));
 624                                 }
 625                                 break;
 626                         }
 627
 628                         /* Account for data printed */
 629                         cp += datalen;
 630                         hlen -= datalen;
 631
 632                         /* Check specification against observed length */
 633                         ++datalen;                      /* option octet */
 634                         if (!ZEROLENOPT(opt))
 635                                 ++datalen;              /* size octet */
 636                         if (datalen != len)
 637                                 ND_PRINT((ndo, "[len %d]", len));
 638                         ch = ',';
 639                         if (opt == TCPOPT_EOL)
 640                                 break;
 641                 }
 642                 ND_PRINT((ndo, "]"));
 643         }
 644
 645         /*
 646          * Print length field before crawling down the stack.
 647          */
 648         ND_PRINT((ndo, ", length %u", length));
 649
 650         if (length <= 0)
 651                 return;
 652
 653         /*
 654          * Decode payload if necessary.
 655          */
 656         bp += TH_OFF(tp) * 4;
 657         if ((flags & TH_RST) && ndo->ndo_vflag) {
 658                 print_tcp_rst_data(ndo, bp, length);
 659                 return;
 660         }
 661
 662         if (ndo->ndo_packettype) {
 663                 switch (ndo->ndo_packettype) {
 664                 case PT_ZMTP1:
 665                         zmtp1_print(ndo, bp, length);
 666                         break;
 667                 }
 668                 return;
 669         }
 670
 671         if (sport == TELNET_PORT || dport == TELNET_PORT) {
 672                 telnet_print(ndo, bp, length);
 673         } else if (sport == SMTP_PORT || dport == SMTP_PORT) {
 674                 ND_PRINT((ndo, ": "));
 675                 smtp_print(ndo, bp, length);
 676         } else if (sport == BGP_PORT || dport == BGP_PORT)
 677                 bgp_print(ndo, bp, length);
 678         else if (sport == PPTP_PORT || dport == PPTP_PORT)
 679                 pptp_print(ndo, bp);
 680 #ifdef TCPDUMP_DO_SMB
 681         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 682                 nbt_tcp_print(ndo, bp, length);
 683         else if (sport == SMB_PORT || dport == SMB_PORT)
 684                 smb_tcp_print(ndo, bp, length);
 685 #endif
 686         else if (sport == BEEP_PORT || dport == BEEP_PORT)
 687                 beep_print(ndo, bp, length);
 688         else if (sport == OPENFLOW_PORT_OLD || dport == OPENFLOW_PORT_OLD ||
 689                  sport == OPENFLOW_PORT_IANA || dport == OPENFLOW_PORT_IANA)
 690                 openflow_print(ndo, bp, length);
 691         else if (sport == FTP_PORT || dport == FTP_PORT) {
 692                 ND_PRINT((ndo, ": "));
 693                 ftp_print(ndo, bp, length);
 694         } else if (sport == HTTP_PORT || dport == HTTP_PORT ||
 695             sport == HTTP_PORT_ALT || dport == HTTP_PORT_ALT) {
 696                 ND_PRINT((ndo, ": "));
 697                 http_print(ndo, bp, length);
 698         } else if (sport == RTSP_PORT || dport == RTSP_PORT ||
 699             sport == RTSP_PORT_ALT || dport == RTSP_PORT_ALT) {
 700                 ND_PRINT((ndo, ": "));
 701                 rtsp_print(ndo, bp, length);
 702         } else if (length > 2 &&
 703                  (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT ||
 704                   sport == MULTICASTDNS_PORT || dport == MULTICASTDNS_PORT)) {
 705                 /*
 706                  * TCP DNS query has 2byte length at the head.
 707                  * XXX packet could be unaligned, it can go strange
 708                  */
 709                 ns_print(ndo, bp + 2, length - 2, 0);
 710         } else if (sport == MSDP_PORT || dport == MSDP_PORT) {
 711                 msdp_print(ndo, bp, length);
 712         } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) {
 713                 rpki_rtr_print(ndo, bp, length);
 714         }
 715         else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) {
 716                 ldp_print(ndo, bp, length);
 717         }
 718         else if ((sport == NFS_PORT || dport == NFS_PORT) &&
 719                  length >= 4 && ND_TTEST2(*bp, 4)) {
 720                 /*
 721                  * If data present, header length valid, and NFS port used,
 722                  * assume NFS.
 723                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 724                  * to NFS print routines.
 725                  */
 726                 uint32_t fraglen;
 727                 register const struct sunrpc_msg *rp;
 728                 enum sunrpc_msg_type direction;
 729
 730                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 731                 if (fraglen > (length) - 4)
 732                         fraglen = (length) - 4;
 733                 rp = (const struct sunrpc_msg *)(bp + 4);
 734                 if (ND_TTEST(rp->rm_direction)) {
 735                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 736                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 737                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 738                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 739                                 return;
 740                         }
 741                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 742                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 743                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 744                                 return;
 745                         }
 746                 }
 747         }
 748
 749         return;
 750  bad:
 751         ND_PRINT((ndo, "[bad opt]"));
 752         if (ch != '\0')
 753                 ND_PRINT((ndo, ">"));
 754         return;
 755  trunc:
 756         ND_PRINT((ndo, "[|tcp]"));
 757         if (ch != '\0')
 758                 ND_PRINT((ndo, ">"));
 759 }
 760
 761 /*
 762  * RFC1122 says the following on data in RST segments:
 763  *
 764  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 765  *
 766  *            A TCP SHOULD allow a received RST segment to include data.
 767  *
 768  *            DISCUSSION
 769  *                 It has been suggested that a RST segment could contain
 770  *                 ASCII text that encoded and explained the cause of the
 771  *                 RST.  No standard has yet been established for such
 772  *                 data.
 773  *
 774  */
 775
 776 static void
 777 print_tcp_rst_data(netdissect_options *ndo,
 778                    register const u_char *sp, u_int length)
 779 {
 780         int c;
 781
 782         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 783         if (length > MAX_RST_DATA_LEN) {
 784                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 785                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 786         }
 787         ND_PRINT((ndo, " "));
 788         while (length-- && sp <= ndo->ndo_snapend) {
 789                 c = *sp++;
 790                 safeputchar(ndo, c);
 791         }
 792         ND_PRINT((ndo, "]"));
 793 }
 794
 795 static void
 796 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 797                           u_int datalen, int exp)
 798 {
 799         u_int i;
 800
 801         if (exp)
 802                 ND_PRINT((ndo, "tfo"));
 803
 804         if (datalen == 0) {
 805                 /* Fast Open Cookie Request */
 806                 ND_PRINT((ndo, " cookiereq"));
 807         } else {
 808                 /* Fast Open Cookie */
 809                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 810                         ND_PRINT((ndo, " malformed"));
 811                 } else {
 812                         ND_PRINT((ndo, " cookie "));
 813                         for (i = 0; i < datalen; ++i)
 814                                 ND_PRINT((ndo, "%02x", cp[i]));
 815                 }
 816         }
 817 }
 818
 819 #ifdef HAVE_LIBCRYPTO
 820 USES_APPLE_DEPRECATED_API
 821 static int
 822 tcp_verify_signature(netdissect_options *ndo,
 823                      const struct ip *ip, const struct tcphdr *tp,
 824                      const u_char *data, int length, const u_char *rcvsig)
 825 {
 826         struct tcphdr tp1;
 827         u_char sig[TCP_SIGLEN];
 828         char zero_proto = 0;
 829         MD5_CTX ctx;
 830         uint16_t savecsum, tlen;
 831 #ifdef INET6
 832         const struct ip6_hdr *ip6;
 833         uint32_t len32;
 834         uint8_t nxt;
 835 #endif
 836
 837         if (data + length > ndo->ndo_snapend) {
 838                 ND_PRINT((ndo, "snaplen too short, "));
 839                 return (CANT_CHECK_SIGNATURE);
 840         }
 841
 842         tp1 = *tp;
 843
 844         if (ndo->ndo_sigsecret == NULL) {
 845                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 846                 return (CANT_CHECK_SIGNATURE);
 847         }
 848
 849         MD5_Init(&ctx);
 850         /*
 851          * Step 1: Update MD5 hash with IP pseudo-header.
 852          */
 853         if (IP_V(ip) == 4) {
 854                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 855                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 856                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 857                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 858                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 859                 tlen = htons(tlen);
 860                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 861 #ifdef INET6
 862         } else if (IP_V(ip) == 6) {
 863                 ip6 = (const struct ip6_hdr *)ip;
 864                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 865                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 866                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 867                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 868                 nxt = 0;
 869                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 870                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 871                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 872                 nxt = IPPROTO_TCP;
 873                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 874 #endif
 875         } else {
 876 #ifdef INET6
 877                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 878 #else
 879                 ND_PRINT((ndo, "IP version not 4, "));
 880 #endif
 881                 return (CANT_CHECK_SIGNATURE);
 882         }
 883
 884         /*
 885          * Step 2: Update MD5 hash with TCP header, excluding options.
 886          * The TCP checksum must be set to zero.
 887          */
 888         savecsum = tp1.th_sum;
 889         tp1.th_sum = 0;
 890         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 891         tp1.th_sum = savecsum;
 892         /*
 893          * Step 3: Update MD5 hash with TCP segment data, if present.
 894          */
 895         if (length > 0)
 896                 MD5_Update(&ctx, data, length);
 897         /*
 898          * Step 4: Update MD5 hash with shared secret.
 899          */
 900         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 901         MD5_Final(sig, &ctx);
 902
 903         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 904                 return (SIGNATURE_VALID);
 905         else
 906                 return (SIGNATURE_INVALID);
 907 }
 908 USES_APPLE_RST
 909 #endif /* HAVE_LIBCRYPTO */
 910
 911 /*
 912  * Local Variables:
 913  * c-style: whitesmith
 914  * c-basic-offset: 8
 915  * End:
 916  */