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 #include <config.h>
  34
  35 #include "netdissect-stdinc.h"
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39
  40 #define ND_LONGJMP_FROM_TCHECK
  41 #include "netdissect.h"
  42 #include "addrtoname.h"
  43 #include "extract.h"
  44
  45 #include "diag-control.h"
  46
  47 #include "tcp.h"
  48
  49 #include "ip.h"
  50 #include "ip6.h"
  51 #include "ipproto.h"
  52 #include "rpc_auth.h"
  53 #include "rpc_msg.h"
  54
  55 #ifdef HAVE_LIBCRYPTO
  56 #include <openssl/md5.h>
  57 #include "signature.h"
  58
  59 static int tcp_verify_signature(netdissect_options *ndo,
  60                                 const struct ip *ip, const struct tcphdr *tp,
  61                                 const u_char *data, u_int length, const u_char *rcvsig);
  62 #endif
  63
  64 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length);
  65 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
  66                                       u_int datalen);
  67
  68 #define MAX_RST_DATA_LEN        30
  69
  70
  71 struct tha {
  72         nd_ipv4 src;
  73         nd_ipv4 dst;
  74         u_int port;
  75 };
  76
  77 struct tcp_seq_hash {
  78         struct tcp_seq_hash *nxt;
  79         struct tha addr;
  80         uint32_t seq;
  81         uint32_t ack;
  82 };
  83
  84 struct tha6 {
  85         nd_ipv6 src;
  86         nd_ipv6 dst;
  87         u_int port;
  88 };
  89
  90 struct tcp_seq_hash6 {
  91         struct tcp_seq_hash6 *nxt;
  92         struct tha6 addr;
  93         uint32_t seq;
  94         uint32_t ack;
  95 };
  96
  97 #define TSEQ_HASHSIZE 919
  98
  99 /* These tcp options do not have the size octet */
 100 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 101
 102 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 103 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 104
 105 const struct tok tcp_flag_values[] = {
 106         { TH_FIN, "F" },
 107         { TH_SYN, "S" },
 108         { TH_RST, "R" },
 109         { TH_PUSH, "P" },
 110         { TH_ACK, "." },
 111         { TH_URG, "U" },
 112         { TH_ECNECHO, "E" },
 113         { TH_CWR, "W" },
 114         { TH_AE, "e" },
 115         { 0, NULL }
 116 };
 117
 118 static const struct tok tcp_option_values[] = {
 119         { TCPOPT_EOL, "eol" },
 120         { TCPOPT_NOP, "nop" },
 121         { TCPOPT_MAXSEG, "mss" },
 122         { TCPOPT_WSCALE, "wscale" },
 123         { TCPOPT_SACKOK, "sackOK" },
 124         { TCPOPT_SACK, "sack" },
 125         { TCPOPT_ECHO, "echo" },
 126         { TCPOPT_ECHOREPLY, "echoreply" },
 127         { TCPOPT_TIMESTAMP, "TS" },
 128         { TCPOPT_CC, "cc" },
 129         { TCPOPT_CCNEW, "ccnew" },
 130         { TCPOPT_CCECHO, "ccecho" },
 131         { TCPOPT_SIGNATURE, "md5" },
 132         { TCPOPT_SCPS, "scps" },
 133         { TCPOPT_UTO, "uto" },
 134         { TCPOPT_TCPAO, "tcp-ao" },
 135         { TCPOPT_MPTCP, "mptcp" },
 136         { TCPOPT_FASTOPEN, "tfo" },
 137         { TCPOPT_EXPERIMENT2, "exp" },
 138         { 0, NULL }
 139 };
 140
 141 static uint16_t
 142 tcp_cksum(netdissect_options *ndo,
 143           const struct ip *ip,
 144           const struct tcphdr *tp,
 145           u_int len)
 146 {
 147         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 148                                 IPPROTO_TCP);
 149 }
 150
 151 static uint16_t
 152 tcp6_cksum(netdissect_options *ndo,
 153            const struct ip6_hdr *ip6,
 154            const struct tcphdr *tp,
 155            u_int len)
 156 {
 157         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 158                                 IPPROTO_TCP);
 159 }
 160
 161 void
 162 tcp_print(netdissect_options *ndo,
 163           const u_char *bp, u_int length,
 164           const u_char *bp2, int fragmented)
 165 {
 166         const struct tcphdr *tp;
 167         const struct ip *ip;
 168         uint16_t flags;
 169         u_int hlen;
 170         char ch;
 171         uint16_t sport, dport, win, urp;
 172         uint32_t seq, ack, thseq, thack;
 173         u_int utoval;
 174         uint16_t magic;
 175         int rev;
 176         const struct ip6_hdr *ip6;
 177         u_int header_len;       /* Header length in bytes */
 178
 179         ndo->ndo_protocol = "tcp";
 180         tp = (const struct tcphdr *)bp;
 181         ip = (const struct ip *)bp2;
 182         if (IP_V(ip) == 6)
 183                 ip6 = (const struct ip6_hdr *)bp2;
 184         else
 185                 ip6 = NULL;
 186         ch = '\0';
 187         if (!ND_TTEST_2(tp->th_dport)) {
 188                 if (ip6) {
 189                         ND_PRINT("%s > %s:",
 190                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 191                                  GET_IP6ADDR_STRING(ip6->ip6_dst));
 192                 } else {
 193                         ND_PRINT("%s > %s:",
 194                                  GET_IPADDR_STRING(ip->ip_src),
 195                                  GET_IPADDR_STRING(ip->ip_dst));
 196                 }
 197                 nd_trunc_longjmp(ndo);
 198         }
 199
 200         sport = GET_BE_U_2(tp->th_sport);
 201         dport = GET_BE_U_2(tp->th_dport);
 202
 203         if (ip6) {
 204                 if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
 205                         ND_PRINT("%s.%s > %s.%s: ",
 206                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 207                                  tcpport_string(ndo, sport),
 208                                  GET_IP6ADDR_STRING(ip6->ip6_dst),
 209                                  tcpport_string(ndo, dport));
 210                 } else {
 211                         ND_PRINT("%s > %s: ",
 212                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 213                 }
 214         } else {
 215                 if (GET_U_1(ip->ip_p) == IPPROTO_TCP) {
 216                         ND_PRINT("%s.%s > %s.%s: ",
 217                                  GET_IPADDR_STRING(ip->ip_src),
 218                                  tcpport_string(ndo, sport),
 219                                  GET_IPADDR_STRING(ip->ip_dst),
 220                                  tcpport_string(ndo, dport));
 221                 } else {
 222                         ND_PRINT("%s > %s: ",
 223                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 224                 }
 225         }
 226
 227         hlen = TH_OFF(tp) * 4;
 228
 229         if (hlen < sizeof(*tp)) {
 230                 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]",
 231                          length - hlen, hlen, sizeof(*tp));
 232                 goto invalid;
 233         }
 234
 235         seq = GET_BE_U_4(tp->th_seq);
 236         ack = GET_BE_U_4(tp->th_ack);
 237         win = GET_BE_U_2(tp->th_win);
 238         urp = GET_BE_U_2(tp->th_urp);
 239
 240         if (ndo->ndo_qflag) {
 241                 ND_PRINT("tcp %u", length - hlen);
 242                 if (hlen > length) {
 243                         ND_PRINT(" [bad hdr length %u - too long, > %u]",
 244                                  hlen, length);
 245                         goto invalid;
 246                 }
 247                 return;
 248         }
 249
 250         flags = tcp_get_flags(tp);
 251         ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 252
 253         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 254                 /*
 255                  * Find (or record) the initial sequence numbers for
 256                  * this conversation.  (we pick an arbitrary
 257                  * collating order so there's only one entry for
 258                  * both directions).
 259                  */
 260                 rev = 0;
 261                 if (ip6) {
 262                         struct tcp_seq_hash6 *th;
 263                         struct tcp_seq_hash6 *tcp_seq_hash;
 264                         const void *src, *dst;
 265                         struct tha6 tha;
 266
 267                         tcp_seq_hash = tcp_seq_hash6;
 268                         src = (const void *)ip6->ip6_src;
 269                         dst = (const void *)ip6->ip6_dst;
 270                         if (sport > dport)
 271                                 rev = 1;
 272                         else if (sport == dport) {
 273                                 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0)
 274                                         rev = 1;
 275                         }
 276                         if (rev) {
 277                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst));
 278                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src));
 279                                 tha.port = ((u_int)dport) << 16 | sport;
 280                         } else {
 281                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst));
 282                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src));
 283                                 tha.port = ((u_int)sport) << 16 | dport;
 284                         }
 285
 286                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 287                              th->nxt; th = th->nxt)
 288                                 if (memcmp((char *)&tha, (char *)&th->addr,
 289                                            sizeof(th->addr)) == 0)
 290                                         break;
 291
 292                         if (!th->nxt || (flags & TH_SYN)) {
 293                                 /* didn't find it or new conversation */
 294                                 /* calloc() return used by the 'tcp_seq_hash6'
 295                                    hash table: do not free() */
 296                                 if (th->nxt == NULL) {
 297                                         th->nxt = (struct tcp_seq_hash6 *)
 298                                                 calloc(1, sizeof(*th));
 299                                         if (th->nxt == NULL)
 300                                                 (*ndo->ndo_error)(ndo,
 301                                                         S_ERR_ND_MEM_ALLOC,
 302                                                         "%s: calloc", __func__);
 303                                 }
 304                                 th->addr = tha;
 305                                 if (rev)
 306                                         th->ack = seq, th->seq = ack - 1;
 307                                 else
 308                                         th->seq = seq, th->ack = ack - 1;
 309                         } else {
 310                                 if (rev)
 311                                         seq -= th->ack, ack -= th->seq;
 312                                 else
 313                                         seq -= th->seq, ack -= th->ack;
 314                         }
 315
 316                         thseq = th->seq;
 317                         thack = th->ack;
 318                 } else {
 319                         struct tcp_seq_hash *th;
 320                         struct tcp_seq_hash *tcp_seq_hash;
 321                         struct tha tha;
 322
 323                         tcp_seq_hash = tcp_seq_hash4;
 324                         if (sport > dport)
 325                                 rev = 1;
 326                         else if (sport == dport) {
 327                                 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0)
 328                                         rev = 1;
 329                         }
 330                         if (rev) {
 331                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst,
 332                                                  sizeof(ip->ip_dst));
 333                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src,
 334                                                  sizeof(ip->ip_src));
 335                                 tha.port = ((u_int)dport) << 16 | sport;
 336                         } else {
 337                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst,
 338                                                  sizeof(ip->ip_dst));
 339                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_src,
 340                                                  sizeof(ip->ip_src));
 341                                 tha.port = ((u_int)sport) << 16 | dport;
 342                         }
 343
 344                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 345                              th->nxt; th = th->nxt)
 346                                 if (memcmp((char *)&tha, (char *)&th->addr,
 347                                            sizeof(th->addr)) == 0)
 348                                         break;
 349
 350                         if (!th->nxt || (flags & TH_SYN)) {
 351                                 /* didn't find it or new conversation */
 352                                 /* calloc() return used by the 'tcp_seq_hash4'
 353                                    hash table: do not free() */
 354                                 if (th->nxt == NULL) {
 355                                         th->nxt = (struct tcp_seq_hash *)
 356                                                 calloc(1, sizeof(*th));
 357                                         if (th->nxt == NULL)
 358                                                 (*ndo->ndo_error)(ndo,
 359                                                         S_ERR_ND_MEM_ALLOC,
 360                                                         "%s: calloc", __func__);
 361                                 }
 362                                 th->addr = tha;
 363                                 if (rev)
 364                                         th->ack = seq, th->seq = ack - 1;
 365                                 else
 366                                         th->seq = seq, th->ack = ack - 1;
 367                         } else {
 368                                 if (rev)
 369                                         seq -= th->ack, ack -= th->seq;
 370                                 else
 371                                         seq -= th->seq, ack -= th->ack;
 372                         }
 373
 374                         thseq = th->seq;
 375                         thack = th->ack;
 376                 }
 377         } else {
 378                 /*fool gcc*/
 379                 thseq = thack = rev = 0;
 380         }
 381         if (hlen > length) {
 382                 ND_PRINT(" [bad hdr length %u - too long, > %u]",
 383                          hlen, length);
 384                 goto invalid;
 385         }
 386
 387         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 388                 /* Check the checksum, if possible. */
 389                 uint16_t sum, tcp_sum;
 390
 391                 if (IP_V(ip) == 4) {
 392                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 393                                 sum = tcp_cksum(ndo, ip, tp, length);
 394                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 395
 396                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 397                                 if (sum != 0)
 398                                         ND_PRINT(" (incorrect -> 0x%04x)",
 399                                             in_cksum_shouldbe(tcp_sum, sum));
 400                                 else
 401                                         ND_PRINT(" (correct)");
 402                         }
 403                 } else if (IP_V(ip) == 6) {
 404                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 405                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 406                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 407
 408                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 409                                 if (sum != 0)
 410                                         ND_PRINT(" (incorrect -> 0x%04x)",
 411                                             in_cksum_shouldbe(tcp_sum, sum));
 412                                 else
 413                                         ND_PRINT(" (correct)");
 414
 415                         }
 416                 }
 417         }
 418
 419         length -= hlen;
 420         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 421                 ND_PRINT(", seq %u", seq);
 422
 423                 if (length > 0) {
 424                         ND_PRINT(":%u", seq + length);
 425                 }
 426         }
 427
 428         if (flags & TH_ACK) {
 429                 ND_PRINT(", ack %u", ack);
 430         }
 431
 432         ND_PRINT(", win %u", win);
 433
 434         if (flags & TH_URG)
 435                 ND_PRINT(", urg %u", urp);
 436         /*
 437          * Handle any options.
 438          */
 439         if (hlen > sizeof(*tp)) {
 440                 const u_char *cp;
 441                 u_int i, opt, datalen;
 442                 u_int len;
 443
 444                 hlen -= sizeof(*tp);
 445                 cp = (const u_char *)tp + sizeof(*tp);
 446                 ND_PRINT(", options [");
 447                 while (hlen != 0) {
 448                         if (ch != '\0')
 449                                 ND_PRINT("%c", ch);
 450                         opt = GET_U_1(cp);
 451                         cp++;
 452                         if (ZEROLENOPT(opt))
 453                                 len = 1;
 454                         else {
 455                                 len = GET_U_1(cp);
 456                                 cp++;   /* total including type, len */
 457                                 if (len < 2 || len > hlen)
 458                                         goto bad;
 459                                 --hlen;         /* account for length byte */
 460                         }
 461                         --hlen;                 /* account for type byte */
 462                         datalen = 0;
 463
 464 /* Bail if "l" bytes of data are not left or were not captured  */
 465 #define LENCHECK(l) { if ((l) > hlen) goto bad; }
 466
 467
 468                         ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 469
 470                         switch (opt) {
 471
 472                         case TCPOPT_MAXSEG:
 473                                 datalen = 2;
 474                                 LENCHECK(datalen);
 475                                 ND_PRINT(" %u", GET_BE_U_2(cp));
 476                                 break;
 477
 478                         case TCPOPT_WSCALE:
 479                                 datalen = 1;
 480                                 LENCHECK(datalen);
 481                                 ND_PRINT(" %u", GET_U_1(cp));
 482                                 break;
 483
 484                         case TCPOPT_SACK:
 485                                 datalen = len - 2;
 486                                 if (datalen % 8 != 0) {
 487                                         ND_PRINT(" invalid sack");
 488                                 } else {
 489                                         uint32_t s, e;
 490
 491                                         ND_PRINT(" %u ", datalen / 8);
 492                                         for (i = 0; i < datalen; i += 8) {
 493                                                 LENCHECK(i + 4);
 494                                                 s = GET_BE_U_4(cp + i);
 495                                                 LENCHECK(i + 8);
 496                                                 e = GET_BE_U_4(cp + i + 4);
 497                                                 if (rev) {
 498                                                         s -= thseq;
 499                                                         e -= thseq;
 500                                                 } else {
 501                                                         s -= thack;
 502                                                         e -= thack;
 503                                                 }
 504                                                 ND_PRINT("{%u:%u}", s, e);
 505                                         }
 506                                 }
 507                                 break;
 508
 509                         case TCPOPT_CC:
 510                         case TCPOPT_CCNEW:
 511                         case TCPOPT_CCECHO:
 512                         case TCPOPT_ECHO:
 513                         case TCPOPT_ECHOREPLY:
 514
 515                                 /*
 516                                  * those options share their semantics.
 517                                  * fall through
 518                                  */
 519                                 datalen = 4;
 520                                 LENCHECK(datalen);
 521                                 ND_PRINT(" %u", GET_BE_U_4(cp));
 522                                 break;
 523
 524                         case TCPOPT_TIMESTAMP:
 525                                 datalen = 8;
 526                                 LENCHECK(datalen);
 527                                 ND_PRINT(" val %u ecr %u",
 528                                              GET_BE_U_4(cp),
 529                                              GET_BE_U_4(cp + 4));
 530                                 break;
 531
 532                         case TCPOPT_SIGNATURE:
 533                                 datalen = TCP_SIGLEN;
 534                                 LENCHECK(datalen);
 535                                 ND_TCHECK_LEN(cp, datalen);
 536                                 ND_PRINT(" ");
 537 #ifdef HAVE_LIBCRYPTO
 538                                 switch (tcp_verify_signature(ndo, ip, tp,
 539                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 540
 541                                 case SIGNATURE_VALID:
 542                                         ND_PRINT("valid");
 543                                         break;
 544
 545                                 case SIGNATURE_INVALID:
 546                                         nd_print_invalid(ndo);
 547                                         break;
 548
 549                                 case CANT_CHECK_SIGNATURE:
 550                                         ND_PRINT("can't check - ");
 551                                         for (i = 0; i < TCP_SIGLEN; ++i)
 552                                                 ND_PRINT("%02x",
 553                                                          GET_U_1(cp + i));
 554                                         break;
 555                                 }
 556 #else
 557                                 for (i = 0; i < TCP_SIGLEN; ++i)
 558                                         ND_PRINT("%02x", GET_U_1(cp + i));
 559 #endif
 560                                 break;
 561
 562                         case TCPOPT_SCPS:
 563                                 datalen = 2;
 564                                 LENCHECK(datalen);
 565                                 ND_PRINT(" cap %02x id %u", GET_U_1(cp),
 566                                          GET_U_1(cp + 1));
 567                                 break;
 568
 569                         case TCPOPT_TCPAO:
 570                                 datalen = len - 2;
 571                                 /* RFC 5925 Section 2.2:
 572                                  * "The Length value MUST be greater than or equal to 4."
 573                                  * (This includes the Kind and Length fields already processed
 574                                  * at this point.)
 575                                  */
 576                                 if (datalen < 2) {
 577                                         nd_print_invalid(ndo);
 578                                 } else {
 579                                         LENCHECK(1);
 580                                         ND_PRINT(" keyid %u", GET_U_1(cp));
 581                                         LENCHECK(2);
 582                                         ND_PRINT(" rnextkeyid %u",
 583                                                  GET_U_1(cp + 1));
 584                                         if (datalen > 2) {
 585                                                 ND_PRINT(" mac 0x");
 586                                                 for (i = 2; i < datalen; i++) {
 587                                                         LENCHECK(i + 1);
 588                                                         ND_PRINT("%02x",
 589                                                                  GET_U_1(cp + i));
 590                                                 }
 591                                         }
 592                                 }
 593                                 break;
 594
 595                         case TCPOPT_EOL:
 596                         case TCPOPT_NOP:
 597                         case TCPOPT_SACKOK:
 598                                 /*
 599                                  * Nothing interesting.
 600                                  * fall through
 601                                  */
 602                                 break;
 603
 604                         case TCPOPT_UTO:
 605                                 datalen = 2;
 606                                 LENCHECK(datalen);
 607                                 utoval = GET_BE_U_2(cp);
 608                                 ND_PRINT(" 0x%x", utoval);
 609                                 if (utoval & 0x0001)
 610                                         utoval = (utoval >> 1) * 60;
 611                                 else
 612                                         utoval >>= 1;
 613                                 ND_PRINT(" %u", utoval);
 614                                 break;
 615
 616                         case TCPOPT_MPTCP:
 617                             {
 618                                 const u_char *snapend_save;
 619                                 int ret;
 620
 621                                 datalen = len - 2;
 622                                 LENCHECK(datalen);
 623                                 /* FIXME: Proof-read mptcp_print() and if it
 624                                  * always covers all bytes when it returns 1,
 625                                  * only do ND_TCHECK_LEN() if it returned 0.
 626                                  */
 627                                 ND_TCHECK_LEN(cp, datalen);
 628                                 /* Update the snapend to the end of the option
 629                                  * before calling mptcp_print(). Some options
 630                                  * (MPTCP or others) may be present after a
 631                                  * MPTCP option. This prevents that, in
 632                                  * mptcp_print(), the remaining length < the
 633                                  * remaining caplen.
 634                                  */
 635                                 snapend_save = ndo->ndo_snapend;
 636                                 ndo->ndo_snapend = ND_MIN(cp - 2 + len,
 637                                                           ndo->ndo_snapend);
 638                                 ret = mptcp_print(ndo, cp - 2, len, flags);
 639                                 ndo->ndo_snapend = snapend_save;
 640                                 if (!ret)
 641                                         goto bad;
 642                                 break;
 643                             }
 644
 645                         case TCPOPT_FASTOPEN:
 646                                 datalen = len - 2;
 647                                 LENCHECK(datalen);
 648                                 ND_TCHECK_LEN(cp, datalen);
 649                                 ND_PRINT(" ");
 650                                 print_tcp_fastopen_option(ndo, cp, datalen);
 651                                 break;
 652
 653                         case TCPOPT_EXPERIMENT2:
 654                                 datalen = len - 2;
 655                                 LENCHECK(datalen);
 656                                 ND_TCHECK_LEN(cp, datalen);
 657                                 if (datalen < 2)
 658                                         goto bad;
 659                                 /* RFC6994 */
 660                                 magic = GET_BE_U_2(cp);
 661                                 ND_PRINT("-");
 662
 663                                 switch(magic) {
 664
 665                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 666                                         ND_PRINT("tfo");
 667                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2);
 668                                         break;
 669
 670                                 default:
 671                                         /* Unknown magic number */
 672                                         ND_PRINT("%04x", magic);
 673                                         break;
 674                                 }
 675                                 break;
 676
 677                         default:
 678                                 datalen = len - 2;
 679                                 if (datalen)
 680                                         ND_PRINT(" 0x");
 681                                 for (i = 0; i < datalen; ++i) {
 682                                         LENCHECK(i + 1);
 683                                         ND_PRINT("%02x", GET_U_1(cp + i));
 684                                 }
 685                                 break;
 686                         }
 687
 688                         /* Account for data printed */
 689                         cp += datalen;
 690                         hlen -= datalen;
 691
 692                         /* Check specification against observed length */
 693                         ++datalen;              /* option octet */
 694                         if (!ZEROLENOPT(opt))
 695                                 ++datalen;      /* size octet */
 696                         if (datalen != len)
 697                                 ND_PRINT("[len %u]", len);
 698                         ch = ',';
 699                         if (opt == TCPOPT_EOL)
 700                                 break;
 701                 }
 702                 ND_PRINT("]");
 703         }
 704
 705         /*
 706          * Print length field before crawling down the stack.
 707          */
 708         ND_PRINT(", length %u", length);
 709
 710         if (length == 0)
 711                 return;
 712
 713         /*
 714          * Decode payload if necessary.
 715          */
 716         header_len = TH_OFF(tp) * 4;
 717         /*
 718          * Do a bounds check before decoding the payload.
 719          * At least the header data is required.
 720          */
 721         if (!ND_TTEST_LEN(bp, header_len)) {
 722                 ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
 723                          ND_BYTES_AVAILABLE_AFTER(bp), header_len);
 724                 nd_trunc_longjmp(ndo);
 725         }
 726         bp += header_len;
 727         if ((flags & TH_RST) && ndo->ndo_vflag) {
 728                 print_tcp_rst_data(ndo, bp, length);
 729                 return;
 730         }
 731
 732         if (ndo->ndo_packettype) {
 733                 switch (ndo->ndo_packettype) {
 734                 case PT_ZMTP1:
 735                         zmtp1_print(ndo, bp, length);
 736                         break;
 737                 case PT_RESP:
 738                         resp_print(ndo, bp, length);
 739                         break;
 740                 case PT_DOMAIN:
 741                         /* over_tcp: TRUE, is_mdns: FALSE */
 742                         domain_print(ndo, bp, length, TRUE, FALSE);
 743                         break;
 744                 }
 745                 return;
 746         }
 747
 748         if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 749                 ND_PRINT(": ");
 750                 ftp_print(ndo, bp, length);
 751         } else if (IS_SRC_OR_DST_PORT(SSH_PORT)) {
 752                 ssh_print(ndo, bp, length);
 753         } else if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 754                 telnet_print(ndo, bp, length);
 755         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 756                 ND_PRINT(": ");
 757                 smtp_print(ndo, bp, length);
 758         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 759                 ND_PRINT(": ");
 760                 whois_print(ndo, bp, length);
 761         } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) {
 762                 /* over_tcp: TRUE, is_mdns: FALSE */
 763                 domain_print(ndo, bp, length, TRUE, FALSE);
 764         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT)) {
 765                 ND_PRINT(": ");
 766                 http_print(ndo, bp, length);
 767 #ifdef ENABLE_SMB
 768         } else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) {
 769                 nbt_tcp_print(ndo, bp, length);
 770 #endif
 771         } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) {
 772                 bgp_print(ndo, bp, length);
 773         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 774                 rpki_rtr_print(ndo, bp, length);
 775 #ifdef ENABLE_SMB
 776         } else if (IS_SRC_OR_DST_PORT(SMB_PORT)) {
 777                 smb_tcp_print(ndo, bp, length);
 778 #endif
 779         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT)) {
 780                 ND_PRINT(": ");
 781                 rtsp_print(ndo, bp, length);
 782         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 783                 msdp_print(ndo, bp, length);
 784         } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) {
 785                 ldp_print(ndo, bp, length);
 786         } else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 787                 pptp_print(ndo, bp);
 788         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 789                 resp_print(ndo, bp, length);
 790         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 791                 beep_print(ndo, bp, length);
 792         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) {
 793                 openflow_print(ndo, bp, length);
 794         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 795                 ND_PRINT(": ");
 796                 http_print(ndo, bp, length);
 797         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 798                 ND_PRINT(": ");
 799                 rtsp_print(ndo, bp, length);
 800         } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 801                  length >= 4) {
 802                 /*
 803                  * If data present, header length valid, and NFS port used,
 804                  * assume NFS.
 805                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 806                  * to NFS print routines.
 807                  */
 808                 uint32_t fraglen;
 809                 const struct sunrpc_msg *rp;
 810                 enum sunrpc_msg_type direction;
 811
 812                 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF;
 813                 if (fraglen > (length) - 4)
 814                         fraglen = (length) - 4;
 815                 rp = (const struct sunrpc_msg *)(bp + 4);
 816                 if (ND_TTEST_4(rp->rm_direction)) {
 817                         direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction);
 818                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 819                                 ND_PRINT(": NFS request xid %u ",
 820                                          GET_BE_U_4(rp->rm_xid));
 821                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 822                                 return;
 823                         }
 824                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 825                                 ND_PRINT(": NFS reply xid %u ",
 826                                          GET_BE_U_4(rp->rm_xid));
 827                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 828                                 return;
 829                         }
 830                 }
 831         }
 832
 833         return;
 834 bad:
 835         ND_PRINT("[bad opt]");
 836         if (ch != '\0')
 837                 ND_PRINT("]");
 838         return;
 839 invalid:
 840         nd_print_invalid(ndo);
 841 }
 842
 843 /*
 844  * RFC1122 says the following on data in RST segments:
 845  *
 846  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 847  *
 848  *            A TCP SHOULD allow a received RST segment to include data.
 849  *
 850  *            DISCUSSION
 851  *                 It has been suggested that a RST segment could contain
 852  *                 ASCII text that encoded and explained the cause of the
 853  *                 RST.  No standard has yet been established for such
 854  *                 data.
 855  *
 856  */
 857
 858 static void
 859 print_tcp_rst_data(netdissect_options *ndo,
 860                    const u_char *sp, u_int length)
 861 {
 862         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 863         if (length > MAX_RST_DATA_LEN) {
 864                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 865                 ND_PRINT("+");                  /* indicate we truncate */
 866         }
 867         ND_PRINT(" ");
 868         (void)nd_printn(ndo, sp, length, ndo->ndo_snapend);
 869         ND_PRINT("]");
 870 }
 871
 872 static void
 873 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 874                           u_int datalen)
 875 {
 876         u_int i;
 877
 878         if (datalen == 0) {
 879                 /* Fast Open Cookie Request */
 880                 ND_PRINT(" cookiereq");
 881         } else {
 882                 /* Fast Open Cookie */
 883                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 884                         nd_print_invalid(ndo);
 885                 } else {
 886                         ND_PRINT(" cookie ");
 887                         for (i = 0; i < datalen; ++i)
 888                                 ND_PRINT("%02x", GET_U_1(cp + i));
 889                 }
 890         }
 891 }
 892
 893 #ifdef HAVE_LIBCRYPTO
 894 DIAG_OFF_DEPRECATION
 895 static int
 896 tcp_verify_signature(netdissect_options *ndo,
 897                      const struct ip *ip, const struct tcphdr *tp,
 898                      const u_char *data, u_int length, const u_char *rcvsig)
 899 {
 900         struct tcphdr tp1;
 901         u_char sig[TCP_SIGLEN];
 902         char zero_proto = 0;
 903         MD5_CTX ctx;
 904         uint16_t savecsum, tlen;
 905         const struct ip6_hdr *ip6;
 906         uint32_t len32;
 907         uint8_t nxt;
 908
 909         if (!ND_TTEST_LEN(data, length)) {
 910                 ND_PRINT("snaplen too short, ");
 911                 return (CANT_CHECK_SIGNATURE);
 912         }
 913
 914         tp1 = *tp;
 915
 916         if (ndo->ndo_sigsecret == NULL) {
 917                 ND_PRINT("shared secret not supplied with -M, ");
 918                 return (CANT_CHECK_SIGNATURE);
 919         }
 920
 921         MD5_Init(&ctx);
 922         /*
 923          * Step 1: Update MD5 hash with IP pseudo-header.
 924          */
 925         if (IP_V(ip) == 4) {
 926                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 927                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 928                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 929                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 930                 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 931                 tlen = htons(tlen);
 932                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 933         } else if (IP_V(ip) == 6) {
 934                 ip6 = (const struct ip6_hdr *)ip;
 935                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 936                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 937                 len32 = htonl(GET_BE_U_2(ip6->ip6_plen));
 938                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 939                 nxt = 0;
 940                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 941                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 942                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 943                 nxt = IPPROTO_TCP;
 944                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 945         } else {
 946                 ND_PRINT("IP version not 4 or 6, ");
 947                 return (CANT_CHECK_SIGNATURE);
 948         }
 949
 950         /*
 951          * Step 2: Update MD5 hash with TCP header, excluding options.
 952          * The TCP checksum must be set to zero.
 953          */
 954         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 955         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 956         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 957         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 958         /*
 959          * Step 3: Update MD5 hash with TCP segment data, if present.
 960          */
 961         if (length > 0)
 962                 MD5_Update(&ctx, data, length);
 963         /*
 964          * Step 4: Update MD5 hash with shared secret.
 965          */
 966         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 967         MD5_Final(sig, &ctx);
 968
 969         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 970                 return (SIGNATURE_VALID);
 971         else
 972                 return (SIGNATURE_INVALID);
 973 }
 974 DIAG_ON_DEPRECATION
 975 #endif /* HAVE_LIBCRYPTO */