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 #include "netdissect.h"
  43 #include "addrtoname.h"
  44 #include "extract.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         struct in_addr src;
  72         struct in_addr dst;
  73         u_int port;
  74 };
  75
  76 struct tcp_seq_hash {
  77         struct tcp_seq_hash *nxt;
  78         struct tha addr;
  79         uint32_t seq;
  80         uint32_t ack;
  81 };
  82
  83 struct tha6 {
  84         struct in6_addr src;
  85         struct in6_addr 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 optinos 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, "" },
 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 int
 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 int
 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
 176         ndo->ndo_protocol = "tcp";
 177         tp = (const struct tcphdr *)bp;
 178         ip = (const struct ip *)bp2;
 179         if (IP_V(ip) == 6)
 180                 ip6 = (const struct ip6_hdr *)bp2;
 181         else
 182                 ip6 = NULL;
 183         ch = '\0';
 184         if (!ND_TTEST_2(tp->th_dport)) {
 185                 if (ip6) {
 186                         ND_PRINT("%s > %s: ",
 187                                      ip6addr_string(ndo, ip6->ip6_src),
 188                                      ip6addr_string(ndo, ip6->ip6_dst));
 189                 } else {
 190                         ND_PRINT("%s > %s: [|tcp]",
 191                                      ipaddr_string(ndo, ip->ip_src),
 192                                      ipaddr_string(ndo, ip->ip_dst));
 193                 }
 194                 return;
 195         }
 196
 197         sport = EXTRACT_BE_U_2(tp->th_sport);
 198         dport = EXTRACT_BE_U_2(tp->th_dport);
 199
 200         if (ip6) {
 201                 if (EXTRACT_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
 202                         ND_PRINT("%s.%s > %s.%s: ",
 203                                      ip6addr_string(ndo, ip6->ip6_src),
 204                                      tcpport_string(ndo, sport),
 205                                      ip6addr_string(ndo, ip6->ip6_dst),
 206                                      tcpport_string(ndo, dport));
 207                 } else {
 208                         ND_PRINT("%s > %s: ",
 209                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 210                 }
 211         } else {
 212                 if (EXTRACT_U_1(ip->ip_p) == IPPROTO_TCP) {
 213                         ND_PRINT("%s.%s > %s.%s: ",
 214                                      ipaddr_string(ndo, ip->ip_src),
 215                                      tcpport_string(ndo, sport),
 216                                      ipaddr_string(ndo, ip->ip_dst),
 217                                      tcpport_string(ndo, dport));
 218                 } else {
 219                         ND_PRINT("%s > %s: ",
 220                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 221                 }
 222         }
 223
 224         ND_TCHECK_SIZE(tp);
 225
 226         hlen = TH_OFF(tp) * 4;
 227
 228         if (hlen < sizeof(*tp)) {
 229                 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %lu]",
 230                              length - hlen, hlen, (unsigned long)sizeof(*tp));
 231                 return;
 232         }
 233
 234         seq = EXTRACT_BE_U_4(tp->th_seq);
 235         ack = EXTRACT_BE_U_4(tp->th_ack);
 236         win = EXTRACT_BE_U_2(tp->th_win);
 237         urp = EXTRACT_BE_U_2(tp->th_urp);
 238
 239         if (ndo->ndo_qflag) {
 240                 ND_PRINT("tcp %u", length - hlen);
 241                 if (hlen > length) {
 242                         ND_PRINT(" [bad hdr length %u - too long, > %u]",
 243                                      hlen, length);
 244                 }
 245                 return;
 246         }
 247
 248         flags = EXTRACT_U_1(tp->th_flags);
 249         ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 250
 251         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 252                 /*
 253                  * Find (or record) the initial sequence numbers for
 254                  * this conversation.  (we pick an arbitrary
 255                  * collating order so there's only one entry for
 256                  * both directions).
 257                  */
 258                 rev = 0;
 259                 if (ip6) {
 260                         struct tcp_seq_hash6 *th;
 261                         struct tcp_seq_hash6 *tcp_seq_hash;
 262                         const void *src, *dst;
 263                         struct tha6 tha;
 264
 265                         tcp_seq_hash = tcp_seq_hash6;
 266                         src = (const void *)ip6->ip6_src;
 267                         dst = (const void *)ip6->ip6_dst;
 268                         if (sport > dport)
 269                                 rev = 1;
 270                         else if (sport == dport) {
 271                                 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0)
 272                                         rev = 1;
 273                         }
 274                         if (rev) {
 275                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst));
 276                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src));
 277                                 tha.port = dport << 16 | sport;
 278                         } else {
 279                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst));
 280                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src));
 281                                 tha.port = sport << 16 | dport;
 282                         }
 283
 284                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 285                              th->nxt; th = th->nxt)
 286                                 if (memcmp((char *)&tha, (char *)&th->addr,
 287                                            sizeof(th->addr)) == 0)
 288                                         break;
 289
 290                         if (!th->nxt || (flags & TH_SYN)) {
 291                                 /* didn't find it or new conversation */
 292                                 /* calloc() return used by the 'tcp_seq_hash6'
 293                                    hash table: do not free() */
 294                                 if (th->nxt == NULL) {
 295                                         th->nxt = (struct tcp_seq_hash6 *)
 296                                                 calloc(1, sizeof(*th));
 297                                         if (th->nxt == NULL)
 298                                                 (*ndo->ndo_error)(ndo,
 299                                                         S_ERR_ND_MEM_ALLOC,
 300                                                         "tcp_print: calloc");
 301                                 }
 302                                 th->addr = tha;
 303                                 if (rev)
 304                                         th->ack = seq, th->seq = ack - 1;
 305                                 else
 306                                         th->seq = seq, th->ack = ack - 1;
 307                         } else {
 308                                 if (rev)
 309                                         seq -= th->ack, ack -= th->seq;
 310                                 else
 311                                         seq -= th->seq, ack -= th->ack;
 312                         }
 313
 314                         thseq = th->seq;
 315                         thack = th->ack;
 316                 } else {
 317                         struct tcp_seq_hash *th;
 318                         struct tcp_seq_hash *tcp_seq_hash;
 319                         struct tha tha;
 320
 321                         tcp_seq_hash = tcp_seq_hash4;
 322                         if (sport > dport)
 323                                 rev = 1;
 324                         else if (sport == dport) {
 325                                 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0)
 326                                         rev = 1;
 327                         }
 328                         if (rev) {
 329                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst,
 330                                                  sizeof(ip->ip_dst));
 331                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src,
 332                                                  sizeof(ip->ip_src));
 333                                 tha.port = dport << 16 | sport;
 334                         } else {
 335                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst,
 336                                                  sizeof(ip->ip_dst));
 337                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_src,
 338                                                  sizeof(ip->ip_src));
 339                                 tha.port = sport << 16 | dport;
 340                         }
 341
 342                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 343                              th->nxt; th = th->nxt)
 344                                 if (memcmp((char *)&tha, (char *)&th->addr,
 345                                            sizeof(th->addr)) == 0)
 346                                         break;
 347
 348                         if (!th->nxt || (flags & TH_SYN)) {
 349                                 /* didn't find it or new conversation */
 350                                 /* calloc() return used by the 'tcp_seq_hash4'
 351                                    hash table: do not free() */
 352                                 if (th->nxt == NULL) {
 353                                         th->nxt = (struct tcp_seq_hash *)
 354                                                 calloc(1, sizeof(*th));
 355                                         if (th->nxt == NULL)
 356                                                 (*ndo->ndo_error)(ndo,
 357                                                         S_ERR_ND_MEM_ALLOC,
 358                                                         "tcp_print: calloc");
 359                                 }
 360                                 th->addr = tha;
 361                                 if (rev)
 362                                         th->ack = seq, th->seq = ack - 1;
 363                                 else
 364                                         th->seq = seq, th->ack = ack - 1;
 365                         } else {
 366                                 if (rev)
 367                                         seq -= th->ack, ack -= th->seq;
 368                                 else
 369                                         seq -= th->seq, ack -= th->ack;
 370                         }
 371
 372                         thseq = th->seq;
 373                         thack = th->ack;
 374                 }
 375         } else {
 376                 /*fool gcc*/
 377                 thseq = thack = rev = 0;
 378         }
 379         if (hlen > length) {
 380                 ND_PRINT(" [bad hdr length %u - too long, > %u]",
 381                              hlen, length);
 382                 return;
 383         }
 384
 385         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 386                 /* Check the checksum, if possible. */
 387                 uint16_t sum, tcp_sum;
 388
 389                 if (IP_V(ip) == 4) {
 390                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 391                                 sum = tcp_cksum(ndo, ip, tp, length);
 392                                 tcp_sum = EXTRACT_BE_U_2(tp->th_sum);
 393
 394                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 395                                 if (sum != 0)
 396                                         ND_PRINT(" (incorrect -> 0x%04x)",
 397                                             in_cksum_shouldbe(tcp_sum, sum));
 398                                 else
 399                                         ND_PRINT(" (correct)");
 400                         }
 401                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 402                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 403                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 404                                 tcp_sum = EXTRACT_BE_U_2(tp->th_sum);
 405
 406                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 407                                 if (sum != 0)
 408                                         ND_PRINT(" (incorrect -> 0x%04x)",
 409                                             in_cksum_shouldbe(tcp_sum, sum));
 410                                 else
 411                                         ND_PRINT(" (correct)");
 412
 413                         }
 414                 }
 415         }
 416
 417         length -= hlen;
 418         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 419                 ND_PRINT(", seq %u", seq);
 420
 421                 if (length > 0) {
 422                         ND_PRINT(":%u", seq + length);
 423                 }
 424         }
 425
 426         if (flags & TH_ACK) {
 427                 ND_PRINT(", ack %u", ack);
 428         }
 429
 430         ND_PRINT(", win %u", win);
 431
 432         if (flags & TH_URG)
 433                 ND_PRINT(", urg %u", urp);
 434         /*
 435          * Handle any options.
 436          */
 437         if (hlen > sizeof(*tp)) {
 438                 const u_char *cp;
 439                 u_int i, opt, datalen;
 440                 u_int len;
 441
 442                 hlen -= sizeof(*tp);
 443                 cp = (const u_char *)tp + sizeof(*tp);
 444                 ND_PRINT(", options [");
 445                 while (hlen > 0) {
 446                         if (ch != '\0')
 447                                 ND_PRINT("%c", ch);
 448                         ND_TCHECK_1(cp);
 449                         opt = EXTRACT_U_1(cp);
 450                         cp++;
 451                         if (ZEROLENOPT(opt))
 452                                 len = 1;
 453                         else {
 454                                 ND_TCHECK_1(cp);
 455                                 len = EXTRACT_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; ND_TCHECK_LEN(cp, l); }
 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", EXTRACT_BE_U_2(cp));
 476                                 break;
 477
 478                         case TCPOPT_WSCALE:
 479                                 datalen = 1;
 480                                 LENCHECK(datalen);
 481                                 ND_PRINT(" %u", EXTRACT_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 = EXTRACT_BE_U_4(cp + i);
 495                                                 LENCHECK(i + 8);
 496                                                 e = EXTRACT_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", EXTRACT_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                                              EXTRACT_BE_U_4(cp),
 529                                              EXTRACT_BE_U_4(cp + 4));
 530                                 break;
 531
 532                         case TCPOPT_SIGNATURE:
 533                                 datalen = TCP_SIGLEN;
 534                                 LENCHECK(datalen);
 535                                 ND_PRINT(" ");
 536 #ifdef HAVE_LIBCRYPTO
 537                                 switch (tcp_verify_signature(ndo, ip, tp,
 538                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 539
 540                                 case SIGNATURE_VALID:
 541                                         ND_PRINT("valid");
 542                                         break;
 543
 544                                 case SIGNATURE_INVALID:
 545                                         ND_PRINT("invalid");
 546                                         break;
 547
 548                                 case CANT_CHECK_SIGNATURE:
 549                                         ND_PRINT("can't check - ");
 550                                         for (i = 0; i < TCP_SIGLEN; ++i)
 551                                                 ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 552                                         break;
 553                                 }
 554 #else
 555                                 for (i = 0; i < TCP_SIGLEN; ++i)
 556                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 557 #endif
 558                                 break;
 559
 560                         case TCPOPT_SCPS:
 561                                 datalen = 2;
 562                                 LENCHECK(datalen);
 563                                 ND_PRINT(" cap %02x id %u", EXTRACT_U_1(cp), EXTRACT_U_1(cp + 1));
 564                                 break;
 565
 566                         case TCPOPT_TCPAO:
 567                                 datalen = len - 2;
 568                                 /* RFC 5925 Section 2.2:
 569                                  * "The Length value MUST be greater than or equal to 4."
 570                                  * (This includes the Kind and Length fields already processed
 571                                  * at this point.)
 572                                  */
 573                                 if (datalen < 2) {
 574                                         ND_PRINT(" invalid");
 575                                 } else {
 576                                         LENCHECK(1);
 577                                         ND_PRINT(" keyid %u", EXTRACT_U_1(cp));
 578                                         LENCHECK(2);
 579                                         ND_PRINT(" rnextkeyid %u", EXTRACT_U_1(cp + 1));
 580                                         if (datalen > 2) {
 581                                                 ND_PRINT(" mac 0x");
 582                                                 for (i = 2; i < datalen; i++) {
 583                                                         LENCHECK(i + 1);
 584                                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 585                                                 }
 586                                         }
 587                                 }
 588                                 break;
 589
 590                         case TCPOPT_EOL:
 591                         case TCPOPT_NOP:
 592                         case TCPOPT_SACKOK:
 593                                 /*
 594                                  * Nothing interesting.
 595                                  * fall through
 596                                  */
 597                                 break;
 598
 599                         case TCPOPT_UTO:
 600                                 datalen = 2;
 601                                 LENCHECK(datalen);
 602                                 utoval = EXTRACT_BE_U_2(cp);
 603                                 ND_PRINT(" 0x%x", utoval);
 604                                 if (utoval & 0x0001)
 605                                         utoval = (utoval >> 1) * 60;
 606                                 else
 607                                         utoval >>= 1;
 608                                 ND_PRINT(" %u", utoval);
 609                                 break;
 610
 611                         case TCPOPT_MPTCP:
 612                                 datalen = len - 2;
 613                                 LENCHECK(datalen);
 614                                 if (!mptcp_print(ndo, cp-2, len, flags))
 615                                         goto bad;
 616                                 break;
 617
 618                         case TCPOPT_FASTOPEN:
 619                                 datalen = len - 2;
 620                                 LENCHECK(datalen);
 621                                 ND_PRINT(" ");
 622                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 623                                 break;
 624
 625                         case TCPOPT_EXPERIMENT2:
 626                                 datalen = len - 2;
 627                                 LENCHECK(datalen);
 628                                 if (datalen < 2)
 629                                         goto bad;
 630                                 /* RFC6994 */
 631                                 magic = EXTRACT_BE_U_2(cp);
 632                                 ND_PRINT("-");
 633
 634                                 switch(magic) {
 635
 636                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 637                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 638                                         break;
 639
 640                                 default:
 641                                         /* Unknown magic number */
 642                                         ND_PRINT("%04x", magic);
 643                                         break;
 644                                 }
 645                                 break;
 646
 647                         default:
 648                                 datalen = len - 2;
 649                                 if (datalen)
 650                                         ND_PRINT(" 0x");
 651                                 for (i = 0; i < datalen; ++i) {
 652                                         LENCHECK(i + 1);
 653                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 654                                 }
 655                                 break;
 656                         }
 657
 658                         /* Account for data printed */
 659                         cp += datalen;
 660                         hlen -= datalen;
 661
 662                         /* Check specification against observed length */
 663                         ++datalen;                      /* option octet */
 664                         if (!ZEROLENOPT(opt))
 665                                 ++datalen;              /* size octet */
 666                         if (datalen != len)
 667                                 ND_PRINT("[len %u]", len);
 668                         ch = ',';
 669                         if (opt == TCPOPT_EOL)
 670                                 break;
 671                 }
 672                 ND_PRINT("]");
 673         }
 674
 675         /*
 676          * Print length field before crawling down the stack.
 677          */
 678         ND_PRINT(", length %u", length);
 679
 680         if (length <= 0)
 681                 return;
 682
 683         /*
 684          * Decode payload if necessary.
 685          */
 686         bp += TH_OFF(tp) * 4;
 687         if ((flags & TH_RST) && ndo->ndo_vflag) {
 688                 print_tcp_rst_data(ndo, bp, length);
 689                 return;
 690         }
 691
 692         if (ndo->ndo_packettype) {
 693                 switch (ndo->ndo_packettype) {
 694                 case PT_ZMTP1:
 695                         zmtp1_print(ndo, bp, length);
 696                         break;
 697                 case PT_RESP:
 698                         resp_print(ndo, bp, length);
 699                         break;
 700                 }
 701                 return;
 702         }
 703
 704         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 705                 telnet_print(ndo, bp, length);
 706         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 707                 ND_PRINT(": ");
 708                 smtp_print(ndo, bp, length);
 709         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 710                 ND_PRINT(": ");
 711                 txtproto_print(ndo, bp, length, "whois", NULL, 0); /* RFC 3912 */
 712         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 713                 bgp_print(ndo, bp, length);
 714         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 715                 pptp_print(ndo, bp);
 716         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 717                 resp_print(ndo, bp, length);
 718 #ifdef ENABLE_SMB
 719         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 720                 nbt_tcp_print(ndo, bp, length);
 721         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 722                 smb_tcp_print(ndo, bp, length);
 723 #endif
 724         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 725                 beep_print(ndo, bp, length);
 726         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 727                 openflow_print(ndo, bp, length);
 728         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 729                 ND_PRINT(": ");
 730                 ftp_print(ndo, bp, length);
 731         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 732                 ND_PRINT(": ");
 733                 http_print(ndo, bp, length);
 734         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 735                 ND_PRINT(": ");
 736                 rtsp_print(ndo, bp, length);
 737         } else if (length > 2 &&
 738                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 739                 /*
 740                  * TCP DNS query has 2byte length at the head.
 741                  * XXX packet could be unaligned, it can go strange
 742                  */
 743                 domain_print(ndo, bp + 2, length - 2, 0);
 744         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 745                 msdp_print(ndo, bp, length);
 746         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 747                 rpki_rtr_print(ndo, bp, length);
 748         }
 749         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 750                 ldp_print(ndo, bp, length);
 751         }
 752         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 753                  length >= 4 && ND_TTEST_4(bp)) {
 754                 /*
 755                  * If data present, header length valid, and NFS port used,
 756                  * assume NFS.
 757                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 758                  * to NFS print routines.
 759                  */
 760                 uint32_t fraglen;
 761                 const struct sunrpc_msg *rp;
 762                 enum sunrpc_msg_type direction;
 763
 764                 fraglen = EXTRACT_BE_U_4(bp) & 0x7FFFFFFF;
 765                 if (fraglen > (length) - 4)
 766                         fraglen = (length) - 4;
 767                 rp = (const struct sunrpc_msg *)(bp + 4);
 768                 if (ND_TTEST_4(rp->rm_direction)) {
 769                         direction = (enum sunrpc_msg_type) EXTRACT_BE_U_4(rp->rm_direction);
 770                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 771                                 ND_PRINT(": NFS request xid %u ",
 772                                          EXTRACT_BE_U_4(rp->rm_xid));
 773                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 774                                 return;
 775                         }
 776                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 777                                 ND_PRINT(": NFS reply xid %u ",
 778                                          EXTRACT_BE_U_4(rp->rm_xid));
 779                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 780                                 return;
 781                         }
 782                 }
 783         }
 784
 785         return;
 786  bad:
 787         ND_PRINT("[bad opt]");
 788         if (ch != '\0')
 789                 ND_PRINT(">");
 790         return;
 791  trunc:
 792         ND_PRINT("[|tcp]");
 793         if (ch != '\0')
 794                 ND_PRINT(">");
 795 }
 796
 797 /*
 798  * RFC1122 says the following on data in RST segments:
 799  *
 800  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 801  *
 802  *            A TCP SHOULD allow a received RST segment to include data.
 803  *
 804  *            DISCUSSION
 805  *                 It has been suggested that a RST segment could contain
 806  *                 ASCII text that encoded and explained the cause of the
 807  *                 RST.  No standard has yet been established for such
 808  *                 data.
 809  *
 810  */
 811
 812 static void
 813 print_tcp_rst_data(netdissect_options *ndo,
 814                    const u_char *sp, u_int length)
 815 {
 816         int c;
 817
 818         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 819         if (length > MAX_RST_DATA_LEN) {
 820                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 821                 ND_PRINT("+");                  /* indicate we truncate */
 822         }
 823         ND_PRINT(" ");
 824         while (length-- && sp < ndo->ndo_snapend) {
 825                 c = EXTRACT_U_1(sp);
 826                 sp++;
 827                 fn_print_char(ndo, c);
 828         }
 829         ND_PRINT("]");
 830 }
 831
 832 static void
 833 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 834                           u_int datalen, int exp)
 835 {
 836         u_int i;
 837
 838         if (exp)
 839                 ND_PRINT("tfo");
 840
 841         if (datalen == 0) {
 842                 /* Fast Open Cookie Request */
 843                 ND_PRINT(" cookiereq");
 844         } else {
 845                 /* Fast Open Cookie */
 846                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 847                         ND_PRINT(" invalid");
 848                 } else {
 849                         ND_PRINT(" cookie ");
 850                         for (i = 0; i < datalen; ++i)
 851                                 ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 852                 }
 853         }
 854 }
 855
 856 #ifdef HAVE_LIBCRYPTO
 857 USES_APPLE_DEPRECATED_API
 858 static int
 859 tcp_verify_signature(netdissect_options *ndo,
 860                      const struct ip *ip, const struct tcphdr *tp,
 861                      const u_char *data, u_int length, const u_char *rcvsig)
 862 {
 863         struct tcphdr tp1;
 864         u_char sig[TCP_SIGLEN];
 865         char zero_proto = 0;
 866         MD5_CTX ctx;
 867         uint16_t savecsum, tlen;
 868         const struct ip6_hdr *ip6;
 869         uint32_t len32;
 870         uint8_t nxt;
 871
 872         if (data + length > ndo->ndo_snapend) {
 873                 ND_PRINT("snaplen too short, ");
 874                 return (CANT_CHECK_SIGNATURE);
 875         }
 876
 877         tp1 = *tp;
 878
 879         if (ndo->ndo_sigsecret == NULL) {
 880                 ND_PRINT("shared secret not supplied with -M, ");
 881                 return (CANT_CHECK_SIGNATURE);
 882         }
 883
 884         MD5_Init(&ctx);
 885         /*
 886          * Step 1: Update MD5 hash with IP pseudo-header.
 887          */
 888         if (IP_V(ip) == 4) {
 889                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 890                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 891                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 892                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 893                 tlen = EXTRACT_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 894                 tlen = htons(tlen);
 895                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 896         } else if (IP_V(ip) == 6) {
 897                 ip6 = (const struct ip6_hdr *)ip;
 898                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 899                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 900                 len32 = htonl(EXTRACT_BE_U_2(ip6->ip6_plen));
 901                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 902                 nxt = 0;
 903                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 904                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 905                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 906                 nxt = IPPROTO_TCP;
 907                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 908         } else {
 909                 ND_PRINT("IP version not 4 or 6, ");
 910                 return (CANT_CHECK_SIGNATURE);
 911         }
 912
 913         /*
 914          * Step 2: Update MD5 hash with TCP header, excluding options.
 915          * The TCP checksum must be set to zero.
 916          */
 917         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 918         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 919         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 920         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 921         /*
 922          * Step 3: Update MD5 hash with TCP segment data, if present.
 923          */
 924         if (length > 0)
 925                 MD5_Update(&ctx, data, length);
 926         /*
 927          * Step 4: Update MD5 hash with shared secret.
 928          */
 929         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 930         MD5_Final(sig, &ctx);
 931
 932         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 933                 return (SIGNATURE_VALID);
 934         else
 935                 return (SIGNATURE_INVALID);
 936 }
 937 USES_APPLE_RST
 938 #endif /* HAVE_LIBCRYPTO */