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