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 /* \summary: TCP printer */
  27
  28 #ifndef lint
  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 "netdissect-stdinc.h"
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #define ND_LONGJMP_FROM_TCHECK
  43 #include "netdissect.h"
  44 #include "addrtoname.h"
  45 #include "extract.h"
  46
  47 #include "diag-control.h"
  48
  49 #include "tcp.h"
  50
  51 #include "ip.h"
  52 #include "ip6.h"
  53 #include "ipproto.h"
  54 #include "rpc_auth.h"
  55 #include "rpc_msg.h"
  56
  57 #ifdef HAVE_LIBCRYPTO
  58 #include <openssl/md5.h>
  59 #include "signature.h"
  60
  61 static int tcp_verify_signature(netdissect_options *ndo,
  62                                 const struct ip *ip, const struct tcphdr *tp,
  63                                 const u_char *data, u_int length, const u_char *rcvsig);
  64 #endif
  65
  66 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length);
  67 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
  68                                       u_int datalen);
  69
  70 #define MAX_RST_DATA_LEN        30
  71
  72
  73 struct tha {
  74         nd_ipv4 src;
  75         nd_ipv4 dst;
  76         u_int port;
  77 };
  78
  79 struct tcp_seq_hash {
  80         struct tcp_seq_hash *nxt;
  81         struct tha addr;
  82         uint32_t seq;
  83         uint32_t ack;
  84 };
  85
  86 struct tha6 {
  87         nd_ipv6 src;
  88         nd_ipv6 dst;
  89         u_int port;
  90 };
  91
  92 struct tcp_seq_hash6 {
  93         struct tcp_seq_hash6 *nxt;
  94         struct tha6 addr;
  95         uint32_t seq;
  96         uint32_t ack;
  97 };
  98
  99 #define TSEQ_HASHSIZE 919
 100
 101 /* These tcp options do not have the size octet */
 102 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 103
 104 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 105 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 106
 107 const struct tok tcp_flag_values[] = {
 108         { TH_FIN, "F" },
 109         { TH_SYN, "S" },
 110         { TH_RST, "R" },
 111         { TH_PUSH, "P" },
 112         { TH_ACK, "." },
 113         { TH_URG, "U" },
 114         { TH_ECNECHO, "E" },
 115         { TH_CWR, "W" },
 116         { TH_AE, "e" },
 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, "ccecho" },
 133         { TCPOPT_SIGNATURE, "md5" },
 134         { TCPOPT_SCPS, "scps" },
 135         { TCPOPT_UTO, "uto" },
 136         { TCPOPT_TCPAO, "tcp-ao" },
 137         { TCPOPT_MPTCP, "mptcp" },
 138         { TCPOPT_FASTOPEN, "tfo" },
 139         { TCPOPT_EXPERIMENT2, "exp" },
 140         { 0, NULL }
 141 };
 142
 143 static uint16_t
 144 tcp_cksum(netdissect_options *ndo,
 145           const struct ip *ip,
 146           const struct tcphdr *tp,
 147           u_int len)
 148 {
 149         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 150                                 IPPROTO_TCP);
 151 }
 152
 153 static uint16_t
 154 tcp6_cksum(netdissect_options *ndo,
 155            const struct ip6_hdr *ip6,
 156            const struct tcphdr *tp,
 157            u_int len)
 158 {
 159         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 160                                 IPPROTO_TCP);
 161 }
 162
 163 void
 164 tcp_print(netdissect_options *ndo,
 165           const u_char *bp, u_int length,
 166           const u_char *bp2, int fragmented)
 167 {
 168         const struct tcphdr *tp;
 169         const struct ip *ip;
 170         uint16_t flags;
 171         u_int hlen;
 172         char ch;
 173         uint16_t sport, dport, win, urp;
 174         uint32_t seq, ack, thseq, thack;
 175         u_int utoval;
 176         uint16_t magic;
 177         int rev;
 178         const struct ip6_hdr *ip6;
 179         u_int header_len;       /* Header length in bytes */
 180
 181         ndo->ndo_protocol = "tcp";
 182         tp = (const struct tcphdr *)bp;
 183         ip = (const struct ip *)bp2;
 184         if (IP_V(ip) == 6)
 185                 ip6 = (const struct ip6_hdr *)bp2;
 186         else
 187                 ip6 = NULL;
 188         ch = '\0';
 189         if (!ND_TTEST_2(tp->th_dport)) {
 190                 if (ip6) {
 191                         ND_PRINT("%s > %s:",
 192                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 193                                  GET_IP6ADDR_STRING(ip6->ip6_dst));
 194                 } else {
 195                         ND_PRINT("%s > %s:",
 196                                  GET_IPADDR_STRING(ip->ip_src),
 197                                  GET_IPADDR_STRING(ip->ip_dst));
 198                 }
 199                 nd_trunc_longjmp(ndo);
 200         }
 201
 202         sport = GET_BE_U_2(tp->th_sport);
 203         dport = GET_BE_U_2(tp->th_dport);
 204
 205         if (ip6) {
 206                 if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
 207                         ND_PRINT("%s.%s > %s.%s: ",
 208                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 209                                  tcpport_string(ndo, sport),
 210                                  GET_IP6ADDR_STRING(ip6->ip6_dst),
 211                                  tcpport_string(ndo, dport));
 212                 } else {
 213                         ND_PRINT("%s > %s: ",
 214                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 215                 }
 216         } else {
 217                 if (GET_U_1(ip->ip_p) == IPPROTO_TCP) {
 218                         ND_PRINT("%s.%s > %s.%s: ",
 219                                  GET_IPADDR_STRING(ip->ip_src),
 220                                  tcpport_string(ndo, sport),
 221                                  GET_IPADDR_STRING(ip->ip_dst),
 222                                  tcpport_string(ndo, dport));
 223                 } else {
 224                         ND_PRINT("%s > %s: ",
 225                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 226                 }
 227         }
 228
 229         hlen = TH_OFF(tp) * 4;
 230
 231         if (hlen < sizeof(*tp)) {
 232                 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]",
 233                          length - hlen, hlen, sizeof(*tp));
 234                 goto invalid;
 235         }
 236
 237         seq = GET_BE_U_4(tp->th_seq);
 238         ack = GET_BE_U_4(tp->th_ack);
 239         win = GET_BE_U_2(tp->th_win);
 240         urp = GET_BE_U_2(tp->th_urp);
 241
 242         if (ndo->ndo_qflag) {
 243                 ND_PRINT("tcp %u", length - hlen);
 244                 if (hlen > length) {
 245                         ND_PRINT(" [bad hdr length %u - too long, > %u]",
 246                                  hlen, length);
 247                         goto invalid;
 248                 }
 249                 return;
 250         }
 251
 252         flags = tcp_get_flags(tp);
 253         ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 254
 255         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 256                 /*
 257                  * Find (or record) the initial sequence numbers for
 258                  * this conversation.  (we pick an arbitrary
 259                  * collating order so there's only one entry for
 260                  * both directions).
 261                  */
 262                 rev = 0;
 263                 if (ip6) {
 264                         struct tcp_seq_hash6 *th;
 265                         struct tcp_seq_hash6 *tcp_seq_hash;
 266                         const void *src, *dst;
 267                         struct tha6 tha;
 268
 269                         tcp_seq_hash = tcp_seq_hash6;
 270                         src = (const void *)ip6->ip6_src;
 271                         dst = (const void *)ip6->ip6_dst;
 272                         if (sport > dport)
 273                                 rev = 1;
 274                         else if (sport == dport) {
 275                                 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0)
 276                                         rev = 1;
 277                         }
 278                         if (rev) {
 279                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst));
 280                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src));
 281                                 tha.port = ((u_int)dport) << 16 | sport;
 282                         } else {
 283                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst));
 284                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src));
 285                                 tha.port = ((u_int)sport) << 16 | dport;
 286                         }
 287
 288                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 289                              th->nxt; th = th->nxt)
 290                                 if (memcmp((char *)&tha, (char *)&th->addr,
 291                                            sizeof(th->addr)) == 0)
 292                                         break;
 293
 294                         if (!th->nxt || (flags & TH_SYN)) {
 295                                 /* didn't find it or new conversation */
 296                                 /* calloc() return used by the 'tcp_seq_hash6'
 297                                    hash table: do not free() */
 298                                 if (th->nxt == NULL) {
 299                                         th->nxt = (struct tcp_seq_hash6 *)
 300                                                 calloc(1, sizeof(*th));
 301                                         if (th->nxt == NULL)
 302                                                 (*ndo->ndo_error)(ndo,
 303                                                         S_ERR_ND_MEM_ALLOC,
 304                                                         "%s: calloc", __func__);
 305                                 }
 306                                 th->addr = tha;
 307                                 if (rev)
 308                                         th->ack = seq, th->seq = ack - 1;
 309                                 else
 310                                         th->seq = seq, th->ack = ack - 1;
 311                         } else {
 312                                 if (rev)
 313                                         seq -= th->ack, ack -= th->seq;
 314                                 else
 315                                         seq -= th->seq, ack -= th->ack;
 316                         }
 317
 318                         thseq = th->seq;
 319                         thack = th->ack;
 320                 } else {
 321                         struct tcp_seq_hash *th;
 322                         struct tcp_seq_hash *tcp_seq_hash;
 323                         struct tha tha;
 324
 325                         tcp_seq_hash = tcp_seq_hash4;
 326                         if (sport > dport)
 327                                 rev = 1;
 328                         else if (sport == dport) {
 329                                 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0)
 330                                         rev = 1;
 331                         }
 332                         if (rev) {
 333                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst,
 334                                                  sizeof(ip->ip_dst));
 335                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src,
 336                                                  sizeof(ip->ip_src));
 337                                 tha.port = ((u_int)dport) << 16 | sport;
 338                         } else {
 339                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst,
 340                                                  sizeof(ip->ip_dst));
 341                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_src,
 342                                                  sizeof(ip->ip_src));
 343                                 tha.port = ((u_int)sport) << 16 | dport;
 344                         }
 345
 346                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 347                              th->nxt; th = th->nxt)
 348                                 if (memcmp((char *)&tha, (char *)&th->addr,
 349                                            sizeof(th->addr)) == 0)
 350                                         break;
 351
 352                         if (!th->nxt || (flags & TH_SYN)) {
 353                                 /* didn't find it or new conversation */
 354                                 /* calloc() return used by the 'tcp_seq_hash4'
 355                                    hash table: do not free() */
 356                                 if (th->nxt == NULL) {
 357                                         th->nxt = (struct tcp_seq_hash *)
 358                                                 calloc(1, sizeof(*th));
 359                                         if (th->nxt == NULL)
 360                                                 (*ndo->ndo_error)(ndo,
 361                                                         S_ERR_ND_MEM_ALLOC,
 362                                                         "%s: calloc", __func__);
 363                                 }
 364                                 th->addr = tha;
 365                                 if (rev)
 366                                         th->ack = seq, th->seq = ack - 1;
 367                                 else
 368                                         th->seq = seq, th->ack = ack - 1;
 369                         } else {
 370                                 if (rev)
 371                                         seq -= th->ack, ack -= th->seq;
 372                                 else
 373                                         seq -= th->seq, ack -= th->ack;
 374                         }
 375
 376                         thseq = th->seq;
 377                         thack = th->ack;
 378                 }
 379         } else {
 380                 /*fool gcc*/
 381                 thseq = thack = rev = 0;
 382         }
 383         if (hlen > length) {
 384                 ND_PRINT(" [bad hdr length %u - too long, > %u]",
 385                          hlen, length);
 386                 goto invalid;
 387         }
 388
 389         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 390                 /* Check the checksum, if possible. */
 391                 uint16_t sum, tcp_sum;
 392
 393                 if (IP_V(ip) == 4) {
 394                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 395                                 sum = tcp_cksum(ndo, ip, tp, length);
 396                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 397
 398                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 399                                 if (sum != 0)
 400                                         ND_PRINT(" (incorrect -> 0x%04x)",
 401                                             in_cksum_shouldbe(tcp_sum, sum));
 402                                 else
 403                                         ND_PRINT(" (correct)");
 404                         }
 405                 } else if (IP_V(ip) == 6) {
 406                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 407                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 408                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 409
 410                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 411                                 if (sum != 0)
 412                                         ND_PRINT(" (incorrect -> 0x%04x)",
 413                                             in_cksum_shouldbe(tcp_sum, sum));
 414                                 else
 415                                         ND_PRINT(" (correct)");
 416
 417                         }
 418                 }
 419         }
 420
 421         length -= hlen;
 422         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 423                 ND_PRINT(", seq %u", seq);
 424
 425                 if (length > 0) {
 426                         ND_PRINT(":%u", seq + length);
 427                 }
 428         }
 429
 430         if (flags & TH_ACK) {
 431                 ND_PRINT(", ack %u", ack);
 432         }
 433
 434         ND_PRINT(", win %u", win);
 435
 436         if (flags & TH_URG)
 437                 ND_PRINT(", urg %u", urp);
 438         /*
 439          * Handle any options.
 440          */
 441         if (hlen > sizeof(*tp)) {
 442                 const u_char *cp;
 443                 u_int i, opt, datalen;
 444                 u_int len;
 445
 446                 hlen -= sizeof(*tp);
 447                 cp = (const u_char *)tp + sizeof(*tp);
 448                 ND_PRINT(", options [");
 449                 while (hlen != 0) {
 450                         if (ch != '\0')
 451                                 ND_PRINT("%c", ch);
 452                         opt = GET_U_1(cp);
 453                         cp++;
 454                         if (ZEROLENOPT(opt))
 455                                 len = 1;
 456                         else {
 457                                 len = GET_U_1(cp);
 458                                 cp++;   /* total including type, len */
 459                                 if (len < 2 || len > hlen)
 460                                         goto bad;
 461                                 --hlen;         /* account for length byte */
 462                         }
 463                         --hlen;                 /* account for type byte */
 464                         datalen = 0;
 465
 466 /* Bail if "l" bytes of data are not left or were not captured  */
 467 #define LENCHECK(l) { if ((l) > hlen) goto bad; }
 468
 469
 470                         ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 471
 472                         switch (opt) {
 473
 474                         case TCPOPT_MAXSEG:
 475                                 datalen = 2;
 476                                 LENCHECK(datalen);
 477                                 ND_PRINT(" %u", GET_BE_U_2(cp));
 478                                 break;
 479
 480                         case TCPOPT_WSCALE:
 481                                 datalen = 1;
 482                                 LENCHECK(datalen);
 483                                 ND_PRINT(" %u", GET_U_1(cp));
 484                                 break;
 485
 486                         case TCPOPT_SACK:
 487                                 datalen = len - 2;
 488                                 if (datalen % 8 != 0) {
 489                                         ND_PRINT(" invalid sack");
 490                                 } else {
 491                                         uint32_t s, e;
 492
 493                                         ND_PRINT(" %u ", datalen / 8);
 494                                         for (i = 0; i < datalen; i += 8) {
 495                                                 LENCHECK(i + 4);
 496                                                 s = GET_BE_U_4(cp + i);
 497                                                 LENCHECK(i + 8);
 498                                                 e = GET_BE_U_4(cp + i + 4);
 499                                                 if (rev) {
 500                                                         s -= thseq;
 501                                                         e -= thseq;
 502                                                 } else {
 503                                                         s -= thack;
 504                                                         e -= thack;
 505                                                 }
 506                                                 ND_PRINT("{%u:%u}", s, e);
 507                                         }
 508                                 }
 509                                 break;
 510
 511                         case TCPOPT_CC:
 512                         case TCPOPT_CCNEW:
 513                         case TCPOPT_CCECHO:
 514                         case TCPOPT_ECHO:
 515                         case TCPOPT_ECHOREPLY:
 516
 517                                 /*
 518                                  * those options share their semantics.
 519                                  * fall through
 520                                  */
 521                                 datalen = 4;
 522                                 LENCHECK(datalen);
 523                                 ND_PRINT(" %u", GET_BE_U_4(cp));
 524                                 break;
 525
 526                         case TCPOPT_TIMESTAMP:
 527                                 datalen = 8;
 528                                 LENCHECK(datalen);
 529                                 ND_PRINT(" val %u ecr %u",
 530                                              GET_BE_U_4(cp),
 531                                              GET_BE_U_4(cp + 4));
 532                                 break;
 533
 534                         case TCPOPT_SIGNATURE:
 535                                 datalen = TCP_SIGLEN;
 536                                 LENCHECK(datalen);
 537                                 ND_TCHECK_LEN(cp, datalen);
 538                                 ND_PRINT(" ");
 539 #ifdef HAVE_LIBCRYPTO
 540                                 switch (tcp_verify_signature(ndo, ip, tp,
 541                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 542
 543                                 case SIGNATURE_VALID:
 544                                         ND_PRINT("valid");
 545                                         break;
 546
 547                                 case SIGNATURE_INVALID:
 548                                         nd_print_invalid(ndo);
 549                                         break;
 550
 551                                 case CANT_CHECK_SIGNATURE:
 552                                         ND_PRINT("can't check - ");
 553                                         for (i = 0; i < TCP_SIGLEN; ++i)
 554                                                 ND_PRINT("%02x",
 555                                                          GET_U_1(cp + i));
 556                                         break;
 557                                 }
 558 #else
 559                                 for (i = 0; i < TCP_SIGLEN; ++i)
 560                                         ND_PRINT("%02x", GET_U_1(cp + i));
 561 #endif
 562                                 break;
 563
 564                         case TCPOPT_SCPS:
 565                                 datalen = 2;
 566                                 LENCHECK(datalen);
 567                                 ND_PRINT(" cap %02x id %u", GET_U_1(cp),
 568                                          GET_U_1(cp + 1));
 569                                 break;
 570
 571                         case TCPOPT_TCPAO:
 572                                 datalen = len - 2;
 573                                 /* RFC 5925 Section 2.2:
 574                                  * "The Length value MUST be greater than or equal to 4."
 575                                  * (This includes the Kind and Length fields already processed
 576                                  * at this point.)
 577                                  */
 578                                 if (datalen < 2) {
 579                                         nd_print_invalid(ndo);
 580                                 } else {
 581                                         LENCHECK(1);
 582                                         ND_PRINT(" keyid %u", GET_U_1(cp));
 583                                         LENCHECK(2);
 584                                         ND_PRINT(" rnextkeyid %u",
 585                                                  GET_U_1(cp + 1));
 586                                         if (datalen > 2) {
 587                                                 ND_PRINT(" mac 0x");
 588                                                 for (i = 2; i < datalen; i++) {
 589                                                         LENCHECK(i + 1);
 590                                                         ND_PRINT("%02x",
 591                                                                  GET_U_1(cp + i));
 592                                                 }
 593                                         }
 594                                 }
 595                                 break;
 596
 597                         case TCPOPT_EOL:
 598                         case TCPOPT_NOP:
 599                         case TCPOPT_SACKOK:
 600                                 /*
 601                                  * Nothing interesting.
 602                                  * fall through
 603                                  */
 604                                 break;
 605
 606                         case TCPOPT_UTO:
 607                                 datalen = 2;
 608                                 LENCHECK(datalen);
 609                                 utoval = GET_BE_U_2(cp);
 610                                 ND_PRINT(" 0x%x", utoval);
 611                                 if (utoval & 0x0001)
 612                                         utoval = (utoval >> 1) * 60;
 613                                 else
 614                                         utoval >>= 1;
 615                                 ND_PRINT(" %u", utoval);
 616                                 break;
 617
 618                         case TCPOPT_MPTCP:
 619                             {
 620                                 const u_char *snapend_save;
 621                                 int ret;
 622
 623                                 datalen = len - 2;
 624                                 LENCHECK(datalen);
 625                                 /* FIXME: Proof-read mptcp_print() and if it
 626                                  * always covers all bytes when it returns 1,
 627                                  * only do ND_TCHECK_LEN() if it returned 0.
 628                                  */
 629                                 ND_TCHECK_LEN(cp, datalen);
 630                                 /* Update the snapend to the end of the option
 631                                  * before calling mptcp_print(). Some options
 632                                  * (MPTCP or others) may be present after a
 633                                  * MPTCP option. This prevents that, in
 634                                  * mptcp_print(), the remaining length < the
 635                                  * remaining caplen.
 636                                  */
 637                                 snapend_save = ndo->ndo_snapend;
 638                                 ndo->ndo_snapend = ND_MIN(cp - 2 + len,
 639                                                           ndo->ndo_snapend);
 640                                 ret = mptcp_print(ndo, cp - 2, len, flags);
 641                                 ndo->ndo_snapend = snapend_save;
 642                                 if (!ret)
 643                                         goto bad;
 644                                 break;
 645                             }
 646
 647                         case TCPOPT_FASTOPEN:
 648                                 datalen = len - 2;
 649                                 LENCHECK(datalen);
 650                                 ND_TCHECK_LEN(cp, datalen);
 651                                 ND_PRINT(" ");
 652                                 print_tcp_fastopen_option(ndo, cp, datalen);
 653                                 break;
 654
 655                         case TCPOPT_EXPERIMENT2:
 656                                 datalen = len - 2;
 657                                 LENCHECK(datalen);
 658                                 ND_TCHECK_LEN(cp, datalen);
 659                                 if (datalen < 2)
 660                                         goto bad;
 661                                 /* RFC6994 */
 662                                 magic = GET_BE_U_2(cp);
 663                                 ND_PRINT("-");
 664
 665                                 switch(magic) {
 666
 667                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 668                                         ND_PRINT("tfo");
 669                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2);
 670                                         break;
 671
 672                                 default:
 673                                         /* Unknown magic number */
 674                                         ND_PRINT("%04x", magic);
 675                                         break;
 676                                 }
 677                                 break;
 678
 679                         default:
 680                                 datalen = len - 2;
 681                                 if (datalen)
 682                                         ND_PRINT(" 0x");
 683                                 for (i = 0; i < datalen; ++i) {
 684                                         LENCHECK(i + 1);
 685                                         ND_PRINT("%02x", GET_U_1(cp + i));
 686                                 }
 687                                 break;
 688                         }
 689
 690                         /* Account for data printed */
 691                         cp += datalen;
 692                         hlen -= datalen;
 693
 694                         /* Check specification against observed length */
 695                         ++datalen;              /* option octet */
 696                         if (!ZEROLENOPT(opt))
 697                                 ++datalen;      /* size octet */
 698                         if (datalen != len)
 699                                 ND_PRINT("[len %u]", len);
 700                         ch = ',';
 701                         if (opt == TCPOPT_EOL)
 702                                 break;
 703                 }
 704                 ND_PRINT("]");
 705         }
 706
 707         /*
 708          * Print length field before crawling down the stack.
 709          */
 710         ND_PRINT(", length %u", length);
 711
 712         if (length == 0)
 713                 return;
 714
 715         /*
 716          * Decode payload if necessary.
 717          */
 718         header_len = TH_OFF(tp) * 4;
 719         /*
 720          * Do a bounds check before decoding the payload.
 721          * At least the header data is required.
 722          */
 723         if (!ND_TTEST_LEN(bp, header_len)) {
 724                 ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
 725                          ND_BYTES_AVAILABLE_AFTER(bp), header_len);
 726                 nd_trunc_longjmp(ndo);
 727         }
 728         bp += header_len;
 729         if ((flags & TH_RST) && ndo->ndo_vflag) {
 730                 print_tcp_rst_data(ndo, bp, length);
 731                 return;
 732         }
 733
 734         if (ndo->ndo_packettype) {
 735                 switch (ndo->ndo_packettype) {
 736                 case PT_ZMTP1:
 737                         zmtp1_print(ndo, bp, length);
 738                         break;
 739                 case PT_RESP:
 740                         resp_print(ndo, bp, length);
 741                         break;
 742                 case PT_DOMAIN:
 743                         /* over_tcp: TRUE, is_mdns: FALSE */
 744                         domain_print(ndo, bp, length, TRUE, FALSE);
 745                         break;
 746                 }
 747                 return;
 748         }
 749
 750         if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 751                 ND_PRINT(": ");
 752                 ftp_print(ndo, bp, length);
 753         } else if (IS_SRC_OR_DST_PORT(SSH_PORT)) {
 754                 ssh_print(ndo, bp, length);
 755         } else if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 756                 telnet_print(ndo, bp, length);
 757         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 758                 ND_PRINT(": ");
 759                 smtp_print(ndo, bp, length);
 760         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 761                 ND_PRINT(": ");
 762                 whois_print(ndo, bp, length);
 763         } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) {
 764                 /* over_tcp: TRUE, is_mdns: FALSE */
 765                 domain_print(ndo, bp, length, TRUE, FALSE);
 766         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT)) {
 767                 ND_PRINT(": ");
 768                 http_print(ndo, bp, length);
 769 #ifdef ENABLE_SMB
 770         } else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) {
 771                 nbt_tcp_print(ndo, bp, length);
 772 #endif
 773         } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) {
 774                 bgp_print(ndo, bp, length);
 775         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 776                 rpki_rtr_print(ndo, bp, length);
 777 #ifdef ENABLE_SMB
 778         } else if (IS_SRC_OR_DST_PORT(SMB_PORT)) {
 779                 smb_tcp_print(ndo, bp, length);
 780 #endif
 781         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT)) {
 782                 ND_PRINT(": ");
 783                 rtsp_print(ndo, bp, length);
 784         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 785                 msdp_print(ndo, bp, length);
 786         } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) {
 787                 ldp_print(ndo, bp, length);
 788         } else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 789                 pptp_print(ndo, bp);
 790         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 791                 resp_print(ndo, bp, length);
 792         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 793                 beep_print(ndo, bp, length);
 794         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) {
 795                 openflow_print(ndo, bp, length);
 796         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 797                 ND_PRINT(": ");
 798                 http_print(ndo, bp, length);
 799         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 800                 ND_PRINT(": ");
 801                 rtsp_print(ndo, bp, length);
 802         } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 803                  length >= 4) {
 804                 /*
 805                  * If data present, header length valid, and NFS port used,
 806                  * assume NFS.
 807                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 808                  * to NFS print routines.
 809                  */
 810                 uint32_t fraglen;
 811                 const struct sunrpc_msg *rp;
 812                 enum sunrpc_msg_type direction;
 813
 814                 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF;
 815                 if (fraglen > (length) - 4)
 816                         fraglen = (length) - 4;
 817                 rp = (const struct sunrpc_msg *)(bp + 4);
 818                 if (ND_TTEST_4(rp->rm_direction)) {
 819                         direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction);
 820                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 821                                 ND_PRINT(": NFS request xid %u ",
 822                                          GET_BE_U_4(rp->rm_xid));
 823                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 824                                 return;
 825                         }
 826                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 827                                 ND_PRINT(": NFS reply xid %u ",
 828                                          GET_BE_U_4(rp->rm_xid));
 829                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 830                                 return;
 831                         }
 832                 }
 833         }
 834
 835         return;
 836 bad:
 837         ND_PRINT("[bad opt]");
 838         if (ch != '\0')
 839                 ND_PRINT("]");
 840         return;
 841 invalid:
 842         nd_print_invalid(ndo);
 843 }
 844
 845 /*
 846  * RFC1122 says the following on data in RST segments:
 847  *
 848  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 849  *
 850  *            A TCP SHOULD allow a received RST segment to include data.
 851  *
 852  *            DISCUSSION
 853  *                 It has been suggested that a RST segment could contain
 854  *                 ASCII text that encoded and explained the cause of the
 855  *                 RST.  No standard has yet been established for such
 856  *                 data.
 857  *
 858  */
 859
 860 static void
 861 print_tcp_rst_data(netdissect_options *ndo,
 862                    const u_char *sp, u_int length)
 863 {
 864         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 865         if (length > MAX_RST_DATA_LEN) {
 866                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 867                 ND_PRINT("+");                  /* indicate we truncate */
 868         }
 869         ND_PRINT(" ");
 870         (void)nd_printn(ndo, sp, length, ndo->ndo_snapend);
 871         ND_PRINT("]");
 872 }
 873
 874 static void
 875 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 876                           u_int datalen)
 877 {
 878         u_int i;
 879
 880         if (datalen == 0) {
 881                 /* Fast Open Cookie Request */
 882                 ND_PRINT(" cookiereq");
 883         } else {
 884                 /* Fast Open Cookie */
 885                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 886                         nd_print_invalid(ndo);
 887                 } else {
 888                         ND_PRINT(" cookie ");
 889                         for (i = 0; i < datalen; ++i)
 890                                 ND_PRINT("%02x", GET_U_1(cp + i));
 891                 }
 892         }
 893 }
 894
 895 #ifdef HAVE_LIBCRYPTO
 896 DIAG_OFF_DEPRECATION
 897 static int
 898 tcp_verify_signature(netdissect_options *ndo,
 899                      const struct ip *ip, const struct tcphdr *tp,
 900                      const u_char *data, u_int length, const u_char *rcvsig)
 901 {
 902         struct tcphdr tp1;
 903         u_char sig[TCP_SIGLEN];
 904         char zero_proto = 0;
 905         MD5_CTX ctx;
 906         uint16_t savecsum, tlen;
 907         const struct ip6_hdr *ip6;
 908         uint32_t len32;
 909         uint8_t nxt;
 910
 911         if (!ND_TTEST_LEN(data, length)) {
 912                 ND_PRINT("snaplen too short, ");
 913                 return (CANT_CHECK_SIGNATURE);
 914         }
 915
 916         tp1 = *tp;
 917
 918         if (ndo->ndo_sigsecret == NULL) {
 919                 ND_PRINT("shared secret not supplied with -M, ");
 920                 return (CANT_CHECK_SIGNATURE);
 921         }
 922
 923         MD5_Init(&ctx);
 924         /*
 925          * Step 1: Update MD5 hash with IP pseudo-header.
 926          */
 927         if (IP_V(ip) == 4) {
 928                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 929                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 930                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 931                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 932                 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 933                 tlen = htons(tlen);
 934                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 935         } else if (IP_V(ip) == 6) {
 936                 ip6 = (const struct ip6_hdr *)ip;
 937                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 938                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 939                 len32 = htonl(GET_BE_U_2(ip6->ip6_plen));
 940                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 941                 nxt = 0;
 942                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 943                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 944                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 945                 nxt = IPPROTO_TCP;
 946                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 947         } else {
 948                 ND_PRINT("IP version not 4 or 6, ");
 949                 return (CANT_CHECK_SIGNATURE);
 950         }
 951
 952         /*
 953          * Step 2: Update MD5 hash with TCP header, excluding options.
 954          * The TCP checksum must be set to zero.
 955          */
 956         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 957         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 958         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 959         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 960         /*
 961          * Step 3: Update MD5 hash with TCP segment data, if present.
 962          */
 963         if (length > 0)
 964                 MD5_Update(&ctx, data, length);
 965         /*
 966          * Step 4: Update MD5 hash with shared secret.
 967          */
 968         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 969         MD5_Final(sig, &ctx);
 970
 971         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 972                 return (SIGNATURE_VALID);
 973         else
 974                 return (SIGNATURE_INVALID);
 975 }
 976 DIAG_ON_DEPRECATION
 977 #endif /* HAVE_LIBCRYPTO */