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 #include "netdissect.h"
  41 #include "addrtoname.h"
  42 #include "extract.h"
  43
  44 #include "diag-control.h"
  45
  46 #include "tcp.h"
  47
  48 #include "ip.h"
  49 #include "ip6.h"
  50 #include "ipproto.h"
  51 #include "rpc_auth.h"
  52 #include "rpc_msg.h"
  53
  54 #ifdef HAVE_LIBCRYPTO
  55 #include <openssl/md5.h>
  56 #include "signature.h"
  57
  58 static int tcp_verify_signature(netdissect_options *ndo,
  59                                 const struct ip *ip, const struct tcphdr *tp,
  60                                 const u_char *data, u_int length, const u_char *rcvsig);
  61 #endif
  62
  63 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length);
  64 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
  65                                       u_int datalen, int exp);
  66
  67 #define MAX_RST_DATA_LEN        30
  68
  69
  70 struct tha {
  71         nd_ipv4 src;
  72         nd_ipv4 dst;
  73         u_int port;
  74 };
  75
  76 struct tcp_seq_hash {
  77         struct tcp_seq_hash *nxt;
  78         struct tha addr;
  79         uint32_t seq;
  80         uint32_t ack;
  81 };
  82
  83 struct tha6 {
  84         nd_ipv6 src;
  85         nd_ipv6 dst;
  86         u_int port;
  87 };
  88
  89 struct tcp_seq_hash6 {
  90         struct tcp_seq_hash6 *nxt;
  91         struct tha6 addr;
  92         uint32_t seq;
  93         uint32_t ack;
  94 };
  95
  96 #define TSEQ_HASHSIZE 919
  97
  98 /* These tcp options do not have the size octet */
  99 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 100
 101 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 102 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 103
 104 static const struct tok tcp_flag_values[] = {
 105         { TH_FIN, "F" },
 106         { TH_SYN, "S" },
 107         { TH_RST, "R" },
 108         { TH_PUSH, "P" },
 109         { TH_ACK, "." },
 110         { TH_URG, "U" },
 111         { TH_ECNECHO, "E" },
 112         { TH_CWR, "W" },
 113         { 0, NULL }
 114 };
 115
 116 static const struct tok tcp_option_values[] = {
 117         { TCPOPT_EOL, "eol" },
 118         { TCPOPT_NOP, "nop" },
 119         { TCPOPT_MAXSEG, "mss" },
 120         { TCPOPT_WSCALE, "wscale" },
 121         { TCPOPT_SACKOK, "sackOK" },
 122         { TCPOPT_SACK, "sack" },
 123         { TCPOPT_ECHO, "echo" },
 124         { TCPOPT_ECHOREPLY, "echoreply" },
 125         { TCPOPT_TIMESTAMP, "TS" },
 126         { TCPOPT_CC, "cc" },
 127         { TCPOPT_CCNEW, "ccnew" },
 128         { TCPOPT_CCECHO, "ccecho" },
 129         { TCPOPT_SIGNATURE, "md5" },
 130         { TCPOPT_SCPS, "scps" },
 131         { TCPOPT_UTO, "uto" },
 132         { TCPOPT_TCPAO, "tcp-ao" },
 133         { TCPOPT_MPTCP, "mptcp" },
 134         { TCPOPT_FASTOPEN, "tfo" },
 135         { TCPOPT_EXPERIMENT2, "exp" },
 136         { 0, NULL }
 137 };
 138
 139 static uint16_t
 140 tcp_cksum(netdissect_options *ndo,
 141           const struct ip *ip,
 142           const struct tcphdr *tp,
 143           u_int len)
 144 {
 145         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 146                                 IPPROTO_TCP);
 147 }
 148
 149 static uint16_t
 150 tcp6_cksum(netdissect_options *ndo,
 151            const struct ip6_hdr *ip6,
 152            const struct tcphdr *tp,
 153            u_int len)
 154 {
 155         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 156                                 IPPROTO_TCP);
 157 }
 158
 159 void
 160 tcp_print(netdissect_options *ndo,
 161           const u_char *bp, u_int length,
 162           const u_char *bp2, int fragmented)
 163 {
 164         const struct tcphdr *tp;
 165         const struct ip *ip;
 166         u_char flags;
 167         u_int hlen;
 168         char ch;
 169         uint16_t sport, dport, win, urp;
 170         uint32_t seq, ack, thseq, thack;
 171         u_int utoval;
 172         uint16_t magic;
 173         int rev;
 174         const struct ip6_hdr *ip6;
 175         u_int header_len;       /* Header length in bytes */
 176
 177         ndo->ndo_protocol = "tcp";
 178         tp = (const struct tcphdr *)bp;
 179         ip = (const struct ip *)bp2;
 180         if (IP_V(ip) == 6)
 181                 ip6 = (const struct ip6_hdr *)bp2;
 182         else
 183                 ip6 = NULL;
 184         ch = '\0';
 185         if (!ND_TTEST_2(tp->th_dport)) {
 186                 if (ip6) {
 187                         ND_PRINT("%s > %s:",
 188                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 189                                  GET_IP6ADDR_STRING(ip6->ip6_dst));
 190                 } else {
 191                         ND_PRINT("%s > %s:",
 192                                  GET_IPADDR_STRING(ip->ip_src),
 193                                  GET_IPADDR_STRING(ip->ip_dst));
 194                 }
 195                 nd_print_trunc(ndo);
 196                 return;
 197         }
 198
 199         sport = GET_BE_U_2(tp->th_sport);
 200         dport = GET_BE_U_2(tp->th_dport);
 201
 202         if (ip6) {
 203                 if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
 204                         ND_PRINT("%s.%s > %s.%s: ",
 205                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 206                                  tcpport_string(ndo, sport),
 207                                  GET_IP6ADDR_STRING(ip6->ip6_dst),
 208                                  tcpport_string(ndo, dport));
 209                 } else {
 210                         ND_PRINT("%s > %s: ",
 211                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 212                 }
 213         } else {
 214                 if (GET_U_1(ip->ip_p) == IPPROTO_TCP) {
 215                         ND_PRINT("%s.%s > %s.%s: ",
 216                                  GET_IPADDR_STRING(ip->ip_src),
 217                                  tcpport_string(ndo, sport),
 218                                  GET_IPADDR_STRING(ip->ip_dst),
 219                                  tcpport_string(ndo, dport));
 220                 } else {
 221                         ND_PRINT("%s > %s: ",
 222                                  tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 223                 }
 224         }
 225
 226         ND_TCHECK_SIZE(tp);
 227
 228         hlen = TH_OFF(tp) * 4;
 229
 230         if (hlen < sizeof(*tp)) {
 231                 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]",
 232                          length - hlen, hlen, sizeof(*tp));
 233                 return;
 234         }
 235
 236         seq = GET_BE_U_4(tp->th_seq);
 237         ack = GET_BE_U_4(tp->th_ack);
 238         win = GET_BE_U_2(tp->th_win);
 239         urp = GET_BE_U_2(tp->th_urp);
 240
 241         if (ndo->ndo_qflag) {
 242                 ND_PRINT("tcp %u", length - hlen);
 243                 if (hlen > length) {
 244                         ND_PRINT(" [bad hdr length %u - too long, > %u]",
 245                                  hlen, length);
 246                 }
 247                 return;
 248         }
 249
 250         flags = GET_U_1(tp->th_flags);
 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                 return;
 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         else
 431                 if (ndo->ndo_vflag > 1 && ack != 0)
 432                         ND_PRINT(", [ack %u != 0 while ACK flag not set]", ack);
 433
 434         ND_PRINT(", win %u", win);
 435
 436         if (flags & TH_URG)
 437                 ND_PRINT(", urg %u", urp);
 438         else
 439                 if (ndo->ndo_vflag > 1 && urp != 0)
 440                         ND_PRINT(", [urg %u != 0 while URG flag not set]", urp);
 441         /*
 442          * Handle any options.
 443          */
 444         if (hlen > sizeof(*tp)) {
 445                 const u_char *cp;
 446                 u_int i, opt, datalen;
 447                 u_int len;
 448
 449                 hlen -= sizeof(*tp);
 450                 cp = (const u_char *)tp + sizeof(*tp);
 451                 ND_PRINT(", options [");
 452                 while (hlen > 0) {
 453                         if (ch != '\0')
 454                                 ND_PRINT("%c", ch);
 455                         opt = GET_U_1(cp);
 456                         cp++;
 457                         if (ZEROLENOPT(opt))
 458                                 len = 1;
 459                         else {
 460                                 len = GET_U_1(cp);
 461                                 cp++;   /* total including type, len */
 462                                 if (len < 2 || len > hlen)
 463                                         goto bad;
 464                                 --hlen;         /* account for length byte */
 465                         }
 466                         --hlen;                 /* account for type byte */
 467                         datalen = 0;
 468
 469 /* Bail if "l" bytes of data are not left or were not captured  */
 470 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK_LEN(cp, l); }
 471
 472
 473                         ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 474
 475                         switch (opt) {
 476
 477                         case TCPOPT_MAXSEG:
 478                                 datalen = 2;
 479                                 LENCHECK(datalen);
 480                                 ND_PRINT(" %u", GET_BE_U_2(cp));
 481                                 break;
 482
 483                         case TCPOPT_WSCALE:
 484                                 datalen = 1;
 485                                 LENCHECK(datalen);
 486                                 ND_PRINT(" %u", GET_U_1(cp));
 487                                 break;
 488
 489                         case TCPOPT_SACK:
 490                                 datalen = len - 2;
 491                                 if (datalen % 8 != 0) {
 492                                         ND_PRINT(" invalid sack");
 493                                 } else {
 494                                         uint32_t s, e;
 495
 496                                         ND_PRINT(" %u ", datalen / 8);
 497                                         for (i = 0; i < datalen; i += 8) {
 498                                                 LENCHECK(i + 4);
 499                                                 s = GET_BE_U_4(cp + i);
 500                                                 LENCHECK(i + 8);
 501                                                 e = GET_BE_U_4(cp + i + 4);
 502                                                 if (rev) {
 503                                                         s -= thseq;
 504                                                         e -= thseq;
 505                                                 } else {
 506                                                         s -= thack;
 507                                                         e -= thack;
 508                                                 }
 509                                                 ND_PRINT("{%u:%u}", s, e);
 510                                         }
 511                                 }
 512                                 break;
 513
 514                         case TCPOPT_CC:
 515                         case TCPOPT_CCNEW:
 516                         case TCPOPT_CCECHO:
 517                         case TCPOPT_ECHO:
 518                         case TCPOPT_ECHOREPLY:
 519
 520                                 /*
 521                                  * those options share their semantics.
 522                                  * fall through
 523                                  */
 524                                 datalen = 4;
 525                                 LENCHECK(datalen);
 526                                 ND_PRINT(" %u", GET_BE_U_4(cp));
 527                                 break;
 528
 529                         case TCPOPT_TIMESTAMP:
 530                                 datalen = 8;
 531                                 LENCHECK(datalen);
 532                                 ND_PRINT(" val %u ecr %u",
 533                                              GET_BE_U_4(cp),
 534                                              GET_BE_U_4(cp + 4));
 535                                 break;
 536
 537                         case TCPOPT_SIGNATURE:
 538                                 datalen = TCP_SIGLEN;
 539                                 LENCHECK(datalen);
 540                                 ND_PRINT(" ");
 541 #ifdef HAVE_LIBCRYPTO
 542                                 switch (tcp_verify_signature(ndo, ip, tp,
 543                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 544
 545                                 case SIGNATURE_VALID:
 546                                         ND_PRINT("valid");
 547                                         break;
 548
 549                                 case SIGNATURE_INVALID:
 550                                         nd_print_invalid(ndo);
 551                                         break;
 552
 553                                 case CANT_CHECK_SIGNATURE:
 554                                         ND_PRINT("can't check - ");
 555                                         for (i = 0; i < TCP_SIGLEN; ++i)
 556                                                 ND_PRINT("%02x",
 557                                                          GET_U_1(cp + i));
 558                                         break;
 559                                 }
 560 #else
 561                                 for (i = 0; i < TCP_SIGLEN; ++i)
 562                                         ND_PRINT("%02x", GET_U_1(cp + i));
 563 #endif
 564                                 break;
 565
 566                         case TCPOPT_SCPS:
 567                                 datalen = 2;
 568                                 LENCHECK(datalen);
 569                                 ND_PRINT(" cap %02x id %u", GET_U_1(cp),
 570                                          GET_U_1(cp + 1));
 571                                 break;
 572
 573                         case TCPOPT_TCPAO:
 574                                 datalen = len - 2;
 575                                 /* RFC 5925 Section 2.2:
 576                                  * "The Length value MUST be greater than or equal to 4."
 577                                  * (This includes the Kind and Length fields already processed
 578                                  * at this point.)
 579                                  */
 580                                 if (datalen < 2) {
 581                                         nd_print_invalid(ndo);
 582                                 } else {
 583                                         LENCHECK(1);
 584                                         ND_PRINT(" keyid %u", GET_U_1(cp));
 585                                         LENCHECK(2);
 586                                         ND_PRINT(" rnextkeyid %u",
 587                                                  GET_U_1(cp + 1));
 588                                         if (datalen > 2) {
 589                                                 ND_PRINT(" mac 0x");
 590                                                 for (i = 2; i < datalen; i++) {
 591                                                         LENCHECK(i + 1);
 592                                                         ND_PRINT("%02x",
 593                                                                  GET_U_1(cp + i));
 594                                                 }
 595                                         }
 596                                 }
 597                                 break;
 598
 599                         case TCPOPT_EOL:
 600                         case TCPOPT_NOP:
 601                         case TCPOPT_SACKOK:
 602                                 /*
 603                                  * Nothing interesting.
 604                                  * fall through
 605                                  */
 606                                 break;
 607
 608                         case TCPOPT_UTO:
 609                                 datalen = 2;
 610                                 LENCHECK(datalen);
 611                                 utoval = GET_BE_U_2(cp);
 612                                 ND_PRINT(" 0x%x", utoval);
 613                                 if (utoval & 0x0001)
 614                                         utoval = (utoval >> 1) * 60;
 615                                 else
 616                                         utoval >>= 1;
 617                                 ND_PRINT(" %u", utoval);
 618                                 break;
 619
 620                         case TCPOPT_MPTCP:
 621                             {
 622                                 const u_char *snapend_save;
 623                                 int ret;
 624
 625                                 datalen = len - 2;
 626                                 LENCHECK(datalen);
 627                                 /* Update the snapend to the end of the option
 628                                  * before calling mptcp_print(). Some options
 629                                  * (MPTCP or others) may be present after a
 630                                  * MPTCP option. This prevents that, in
 631                                  * mptcp_print(), the remaining length < the
 632                                  * remaining caplen.
 633                                  */
 634                                 snapend_save = ndo->ndo_snapend;
 635                                 ndo->ndo_snapend = ND_MIN(cp - 2 + len,
 636                                                           ndo->ndo_snapend);
 637                                 ret = mptcp_print(ndo, cp - 2, len, flags);
 638                                 ndo->ndo_snapend = snapend_save;
 639                                 if (!ret)
 640                                         goto bad;
 641                                 break;
 642                             }
 643
 644                         case TCPOPT_FASTOPEN:
 645                                 datalen = len - 2;
 646                                 LENCHECK(datalen);
 647                                 ND_PRINT(" ");
 648                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 649                                 break;
 650
 651                         case TCPOPT_EXPERIMENT2:
 652                                 datalen = len - 2;
 653                                 LENCHECK(datalen);
 654                                 if (datalen < 2)
 655                                         goto bad;
 656                                 /* RFC6994 */
 657                                 magic = GET_BE_U_2(cp);
 658                                 ND_PRINT("-");
 659
 660                                 switch(magic) {
 661
 662                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 663                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 664                                         break;
 665
 666                                 default:
 667                                         /* Unknown magic number */
 668                                         ND_PRINT("%04x", magic);
 669                                         break;
 670                                 }
 671                                 break;
 672
 673                         default:
 674                                 datalen = len - 2;
 675                                 if (datalen)
 676                                         ND_PRINT(" 0x");
 677                                 for (i = 0; i < datalen; ++i) {
 678                                         LENCHECK(i + 1);
 679                                         ND_PRINT("%02x", GET_U_1(cp + i));
 680                                 }
 681                                 break;
 682                         }
 683
 684                         /* Account for data printed */
 685                         cp += datalen;
 686                         hlen -= datalen;
 687
 688                         /* Check specification against observed length */
 689                         ++datalen;              /* option octet */
 690                         if (!ZEROLENOPT(opt))
 691                                 ++datalen;      /* size octet */
 692                         if (datalen != len)
 693                                 ND_PRINT("[len %u]", len);
 694                         ch = ',';
 695                         if (opt == TCPOPT_EOL)
 696                                 break;
 697                 }
 698                 ND_PRINT("]");
 699         }
 700
 701         /*
 702          * Print length field before crawling down the stack.
 703          */
 704         ND_PRINT(", length %u", length);
 705
 706         if (length == 0)
 707                 return;
 708
 709         /*
 710          * Decode payload if necessary.
 711          */
 712         header_len = TH_OFF(tp) * 4;
 713         /*
 714          * Do a bounds check before decoding the payload.
 715          * At least the header data is required.
 716          */
 717         if (!ND_TTEST_LEN(bp, header_len)) {
 718                 ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
 719                          ND_BYTES_AVAILABLE_AFTER(bp), header_len);
 720                 nd_trunc_longjmp(ndo);
 721         }
 722         bp += header_len;
 723         if (flags & TH_RST) {
 724                 if(ndo->ndo_vflag)
 725                         print_tcp_rst_data(ndo, bp, length);
 726                 else
 727                         ND_TCHECK_LEN(bp, length);
 728                 return;
 729         }
 730
 731         if (ndo->ndo_packettype) {
 732                 switch (ndo->ndo_packettype) {
 733                 case PT_ZMTP1:
 734                         zmtp1_print(ndo, bp, length);
 735                         break;
 736                 case PT_RESP:
 737                         resp_print(ndo, bp, length);
 738                         break;
 739                 case PT_DOMAIN:
 740                         /* over_tcp: TRUE, is_mdns: FALSE */
 741                         domain_print(ndo, bp, length, TRUE, FALSE);
 742                         break;
 743                 }
 744                 return;
 745         }
 746
 747         if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 748                 ND_PRINT(": ");
 749                 ftp_print(ndo, bp, length);
 750         } else if (IS_SRC_OR_DST_PORT(SSH_PORT)) {
 751                 ssh_print(ndo, bp, length);
 752         } else if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 753                 telnet_print(ndo, bp, length);
 754         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 755                 ND_PRINT(": ");
 756                 smtp_print(ndo, bp, length);
 757         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 758                 ND_PRINT(": ");
 759                 whois_print(ndo, bp, length);
 760         } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) {
 761                 /* over_tcp: TRUE, is_mdns: FALSE */
 762                 domain_print(ndo, bp, length, TRUE, FALSE);
 763         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT)) {
 764                 ND_PRINT(": ");
 765                 http_print(ndo, bp, length);
 766 #ifdef ENABLE_SMB
 767         } else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) {
 768                 nbt_tcp_print(ndo, bp, length);
 769 #endif
 770         } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) {
 771                 bgp_print(ndo, bp, length);
 772         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 773                 rpki_rtr_print(ndo, bp, length);
 774 #ifdef ENABLE_SMB
 775         } else if (IS_SRC_OR_DST_PORT(SMB_PORT)) {
 776                 smb_tcp_print(ndo, bp, length);
 777 #endif
 778         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT)) {
 779                 ND_PRINT(": ");
 780                 rtsp_print(ndo, bp, length);
 781         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 782                 msdp_print(ndo, bp, length);
 783         } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) {
 784                 ldp_print(ndo, bp, length);
 785         } else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 786                 pptp_print(ndo, bp);
 787         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 788                 resp_print(ndo, bp, length);
 789         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 790                 beep_print(ndo, bp, length);
 791         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) {
 792                 openflow_print(ndo, bp, length);
 793         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 794                 ND_PRINT(": ");
 795                 http_print(ndo, bp, length);
 796         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 797                 ND_PRINT(": ");
 798                 rtsp_print(ndo, bp, length);
 799         } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 800                  length >= 4 && ND_TTEST_4(bp)) {
 801                 /*
 802                  * If data present, header length valid, and NFS port used,
 803                  * assume NFS.
 804                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 805                  * to NFS print routines.
 806                  */
 807                 uint32_t fraglen;
 808                 const struct sunrpc_msg *rp;
 809                 enum sunrpc_msg_type direction;
 810
 811                 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF;
 812                 if (fraglen > (length) - 4)
 813                         fraglen = (length) - 4;
 814                 rp = (const struct sunrpc_msg *)(bp + 4);
 815                 if (ND_TTEST_4(rp->rm_direction)) {
 816                         direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction);
 817                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 818                                 ND_PRINT(": NFS request xid %u ",
 819                                          GET_BE_U_4(rp->rm_xid));
 820                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 821                                 return;
 822                         }
 823                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 824                                 ND_PRINT(": NFS reply xid %u ",
 825                                          GET_BE_U_4(rp->rm_xid));
 826                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 827                                 return;
 828                         }
 829                 }
 830         }
 831
 832         return;
 833 bad:
 834         ND_PRINT("[bad opt]");
 835         if (ch != '\0')
 836                 ND_PRINT("]");
 837         return;
 838 trunc:
 839         nd_print_trunc(ndo);
 840         if (ch != '\0')
 841                 ND_PRINT(">");
 842 }
 843
 844 /*
 845  * RFC1122 says the following on data in RST segments:
 846  *
 847  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 848  *
 849  *            A TCP SHOULD allow a received RST segment to include data.
 850  *
 851  *            DISCUSSION
 852  *                 It has been suggested that a RST segment could contain
 853  *                 ASCII text that encoded and explained the cause of the
 854  *                 RST.  No standard has yet been established for such
 855  *                 data.
 856  *
 857  */
 858
 859 static void
 860 print_tcp_rst_data(netdissect_options *ndo,
 861                    const u_char *sp, u_int length)
 862 {
 863         u_char c;
 864
 865         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 866         if (length > MAX_RST_DATA_LEN) {
 867                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 868                 ND_PRINT("+");                  /* indicate we truncate */
 869         }
 870         ND_PRINT(" ");
 871         while (length && sp < ndo->ndo_snapend) {
 872                 c = GET_U_1(sp);
 873                 sp++;
 874                 fn_print_char(ndo, c);
 875                 length--;
 876         }
 877         ND_PRINT("]");
 878 }
 879
 880 static void
 881 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 882                           u_int datalen, int exp)
 883 {
 884         u_int i;
 885
 886         if (exp)
 887                 ND_PRINT("tfo");
 888
 889         if (datalen == 0) {
 890                 /* Fast Open Cookie Request */
 891                 ND_PRINT(" cookiereq");
 892         } else {
 893                 /* Fast Open Cookie */
 894                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 895                         nd_print_invalid(ndo);
 896                 } else {
 897                         ND_PRINT(" cookie ");
 898                         for (i = 0; i < datalen; ++i)
 899                                 ND_PRINT("%02x", GET_U_1(cp + i));
 900                 }
 901         }
 902 }
 903
 904 #ifdef HAVE_LIBCRYPTO
 905 DIAG_OFF_DEPRECATION
 906 static int
 907 tcp_verify_signature(netdissect_options *ndo,
 908                      const struct ip *ip, const struct tcphdr *tp,
 909                      const u_char *data, u_int length, const u_char *rcvsig)
 910 {
 911         struct tcphdr tp1;
 912         u_char sig[TCP_SIGLEN];
 913         char zero_proto = 0;
 914         MD5_CTX ctx;
 915         uint16_t savecsum, tlen;
 916         const struct ip6_hdr *ip6;
 917         uint32_t len32;
 918         uint8_t nxt;
 919
 920         if (data + length > ndo->ndo_snapend) {
 921                 ND_PRINT("snaplen too short, ");
 922                 return (CANT_CHECK_SIGNATURE);
 923         }
 924
 925         tp1 = *tp;
 926
 927         if (ndo->ndo_sigsecret == NULL) {
 928                 ND_PRINT("shared secret not supplied with -M, ");
 929                 return (CANT_CHECK_SIGNATURE);
 930         }
 931
 932         MD5_Init(&ctx);
 933         /*
 934          * Step 1: Update MD5 hash with IP pseudo-header.
 935          */
 936         if (IP_V(ip) == 4) {
 937                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 938                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 939                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 940                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 941                 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 942                 tlen = htons(tlen);
 943                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 944         } else if (IP_V(ip) == 6) {
 945                 ip6 = (const struct ip6_hdr *)ip;
 946                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 947                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 948                 len32 = htonl(GET_BE_U_2(ip6->ip6_plen));
 949                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 950                 nxt = 0;
 951                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 952                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 953                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 954                 nxt = IPPROTO_TCP;
 955                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 956         } else {
 957                 ND_PRINT("IP version not 4 or 6, ");
 958                 return (CANT_CHECK_SIGNATURE);
 959         }
 960
 961         /*
 962          * Step 2: Update MD5 hash with TCP header, excluding options.
 963          * The TCP checksum must be set to zero.
 964          */
 965         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 966         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 967         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 968         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 969         /*
 970          * Step 3: Update MD5 hash with TCP segment data, if present.
 971          */
 972         if (length > 0)
 973                 MD5_Update(&ctx, data, length);
 974         /*
 975          * Step 4: Update MD5 hash with shared secret.
 976          */
 977         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 978         MD5_Final(sig, &ctx);
 979
 980         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 981                 return (SIGNATURE_VALID);
 982         else
 983                 return (SIGNATURE_INVALID);
 984 }
 985 DIAG_ON_DEPRECATION
 986 #endif /* HAVE_LIBCRYPTO */