The Tcpdump Group git mirrors - tcpdump/blob - print-tcp.c

   1 /*      $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Copyright (c) 1999-2004 The tcpdump.org project
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that: (1) source code distributions
  11  * retain the above copyright notice and this paragraph in its entirety, (2)
  12  * distributions including binary code include the above copyright notice and
  13  * this paragraph in its entirety in the documentation or other materials
  14  * provided with the distribution, and (3) all advertising materials mentioning
  15  * features or use of this software display the following acknowledgement:
  16  * ``This product includes software developed by the University of California,
  17  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  18  * the University nor the names of its contributors may be used to endorse
  19  * or promote products derived from this software without specific prior
  20  * written permission.
  21  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  24  */
  25
  26 /* \summary: TCP printer */
  27
  28 #ifndef lint
  29 #else
  30 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
  31 #endif
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include <config.h>
  35 #endif
  36
  37 #include "netdissect-stdinc.h"
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #define ND_LONGJMP_FROM_TCHECK
  43 #include "netdissect.h"
  44 #include "addrtoname.h"
  45 #include "extract.h"
  46
  47 #include "diag-control.h"
  48
  49 #include "tcp.h"
  50
  51 #include "ip.h"
  52 #include "ip6.h"
  53 #include "ipproto.h"
  54 #include "rpc_auth.h"
  55 #include "rpc_msg.h"
  56
  57 #ifdef HAVE_LIBCRYPTO
  58 #include <openssl/md5.h>
  59 #include "signature.h"
  60
  61 static int tcp_verify_signature(netdissect_options *ndo,
  62                                 const struct ip *ip, const struct tcphdr *tp,
  63                                 const u_char *data, u_int length, const u_char *rcvsig);
  64 #endif
  65
  66 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length);
  67 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
  68                                       u_int datalen);
  69
  70 #define MAX_RST_DATA_LEN        30
  71
  72
  73 struct tha {
  74         nd_ipv4 src;
  75         nd_ipv4 dst;
  76         u_int port;
  77 };
  78
  79 struct tcp_seq_hash {
  80         struct tcp_seq_hash *nxt;
  81         struct tha addr;
  82         uint32_t seq;
  83         uint32_t ack;
  84 };
  85
  86 struct tha6 {
  87         nd_ipv6 src;
  88         nd_ipv6 dst;
  89         u_int port;
  90 };
  91
  92 struct tcp_seq_hash6 {
  93         struct tcp_seq_hash6 *nxt;
  94         struct tha6 addr;
  95         uint32_t seq;
  96         uint32_t ack;
  97 };
  98
  99 #define TSEQ_HASHSIZE 919
 100
 101 /* These tcp options do not have the size octet */
 102 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 103
 104 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 105 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 106
 107 const struct tok tcp_flag_values[] = {
 108         { TH_FIN, "F" },
 109         { TH_SYN, "S" },
 110         { TH_RST, "R" },
 111         { TH_PUSH, "P" },
 112         { TH_ACK, "." },
 113         { TH_URG, "U" },
 114         { TH_ECNECHO, "E" },
 115         { TH_CWR, "W" },
 116         { 0, NULL }
 117 };
 118
 119 static const struct tok tcp_option_values[] = {
 120         { TCPOPT_EOL, "eol" },
 121         { TCPOPT_NOP, "nop" },
 122         { TCPOPT_MAXSEG, "mss" },
 123         { TCPOPT_WSCALE, "wscale" },
 124         { TCPOPT_SACKOK, "sackOK" },
 125         { TCPOPT_SACK, "sack" },
 126         { TCPOPT_ECHO, "echo" },
 127         { TCPOPT_ECHOREPLY, "echoreply" },
 128         { TCPOPT_TIMESTAMP, "TS" },
 129         { TCPOPT_CC, "cc" },
 130         { TCPOPT_CCNEW, "ccnew" },
 131         { TCPOPT_CCECHO, "" },
 132         { TCPOPT_SIGNATURE, "md5" },
 133         { TCPOPT_SCPS, "scps" },
 134         { TCPOPT_UTO, "uto" },
 135         { TCPOPT_TCPAO, "tcp-ao" },
 136         { TCPOPT_MPTCP, "mptcp" },
 137         { TCPOPT_FASTOPEN, "tfo" },
 138         { TCPOPT_EXPERIMENT2, "exp" },
 139         { 0, NULL }
 140 };
 141
 142 static uint16_t
 143 tcp_cksum(netdissect_options *ndo,
 144           const struct ip *ip,
 145           const struct tcphdr *tp,
 146           u_int len)
 147 {
 148         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 149                                 IPPROTO_TCP);
 150 }
 151
 152 static uint16_t
 153 tcp6_cksum(netdissect_options *ndo,
 154            const struct ip6_hdr *ip6,
 155            const struct tcphdr *tp,
 156            u_int len)
 157 {
 158         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 159                                 IPPROTO_TCP);
 160 }
 161
 162 void
 163 tcp_print(netdissect_options *ndo,
 164           const u_char *bp, u_int length,
 165           const u_char *bp2, int fragmented)
 166 {
 167         const struct tcphdr *tp;
 168         const struct ip *ip;
 169         u_char flags;
 170         u_int hlen;
 171         char ch;
 172         uint16_t sport, dport, win, urp;
 173         uint32_t seq, ack, thseq, thack;
 174         u_int utoval;
 175         uint16_t magic;
 176         int rev;
 177         const struct ip6_hdr *ip6;
 178         u_int header_len;       /* Header length in bytes */
 179
 180         ndo->ndo_protocol = "tcp";
 181         tp = (const struct tcphdr *)bp;
 182         ip = (const struct ip *)bp2;
 183         if (IP_V(ip) == 6)
 184                 ip6 = (const struct ip6_hdr *)bp2;
 185         else
 186                 ip6 = NULL;
 187         ch = '\0';
 188         if (!ND_TTEST_2(tp->th_dport)) {
 189                 if (ip6) {
 190                         ND_PRINT("%s > %s:",
 191                                  GET_IP6ADDR_STRING(ip6->ip6_src),
 192                                  GET_IP6ADDR_STRING(ip6->ip6_dst));
 193                 } else {
 194                         ND_PRINT("%s > %s:",
 195                                  GET_IPADDR_STRING(ip->ip_src),
 196                                  GET_IPADDR_STRING(ip->ip_dst));
 197                 }
 198                 nd_trunc_longjmp(ndo);
 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         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                 goto invalid;
 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                         goto invalid;
 247                 }
 248                 return;
 249         }
 250
 251         flags = GET_U_1(tp->th_flags);
 252         ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 253
 254         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 255                 /*
 256                  * Find (or record) the initial sequence numbers for
 257                  * this conversation.  (we pick an arbitrary
 258                  * collating order so there's only one entry for
 259                  * both directions).
 260                  */
 261                 rev = 0;
 262                 if (ip6) {
 263                         struct tcp_seq_hash6 *th;
 264                         struct tcp_seq_hash6 *tcp_seq_hash;
 265                         const void *src, *dst;
 266                         struct tha6 tha;
 267
 268                         tcp_seq_hash = tcp_seq_hash6;
 269                         src = (const void *)ip6->ip6_src;
 270                         dst = (const void *)ip6->ip6_dst;
 271                         if (sport > dport)
 272                                 rev = 1;
 273                         else if (sport == dport) {
 274                                 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0)
 275                                         rev = 1;
 276                         }
 277                         if (rev) {
 278                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst));
 279                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src));
 280                                 tha.port = ((u_int)dport) << 16 | sport;
 281                         } else {
 282                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst));
 283                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src));
 284                                 tha.port = ((u_int)sport) << 16 | dport;
 285                         }
 286
 287                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 288                              th->nxt; th = th->nxt)
 289                                 if (memcmp((char *)&tha, (char *)&th->addr,
 290                                            sizeof(th->addr)) == 0)
 291                                         break;
 292
 293                         if (!th->nxt || (flags & TH_SYN)) {
 294                                 /* didn't find it or new conversation */
 295                                 /* calloc() return used by the 'tcp_seq_hash6'
 296                                    hash table: do not free() */
 297                                 if (th->nxt == NULL) {
 298                                         th->nxt = (struct tcp_seq_hash6 *)
 299                                                 calloc(1, sizeof(*th));
 300                                         if (th->nxt == NULL)
 301                                                 (*ndo->ndo_error)(ndo,
 302                                                         S_ERR_ND_MEM_ALLOC,
 303                                                         "%s: calloc", __func__);
 304                                 }
 305                                 th->addr = tha;
 306                                 if (rev)
 307                                         th->ack = seq, th->seq = ack - 1;
 308                                 else
 309                                         th->seq = seq, th->ack = ack - 1;
 310                         } else {
 311                                 if (rev)
 312                                         seq -= th->ack, ack -= th->seq;
 313                                 else
 314                                         seq -= th->seq, ack -= th->ack;
 315                         }
 316
 317                         thseq = th->seq;
 318                         thack = th->ack;
 319                 } else {
 320                         struct tcp_seq_hash *th;
 321                         struct tcp_seq_hash *tcp_seq_hash;
 322                         struct tha tha;
 323
 324                         tcp_seq_hash = tcp_seq_hash4;
 325                         if (sport > dport)
 326                                 rev = 1;
 327                         else if (sport == dport) {
 328                                 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0)
 329                                         rev = 1;
 330                         }
 331                         if (rev) {
 332                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst,
 333                                                  sizeof(ip->ip_dst));
 334                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src,
 335                                                  sizeof(ip->ip_src));
 336                                 tha.port = ((u_int)dport) << 16 | sport;
 337                         } else {
 338                                 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst,
 339                                                  sizeof(ip->ip_dst));
 340                                 UNALIGNED_MEMCPY(&tha.src, ip->ip_src,
 341                                                  sizeof(ip->ip_src));
 342                                 tha.port = ((u_int)sport) << 16 | dport;
 343                         }
 344
 345                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 346                              th->nxt; th = th->nxt)
 347                                 if (memcmp((char *)&tha, (char *)&th->addr,
 348                                            sizeof(th->addr)) == 0)
 349                                         break;
 350
 351                         if (!th->nxt || (flags & TH_SYN)) {
 352                                 /* didn't find it or new conversation */
 353                                 /* calloc() return used by the 'tcp_seq_hash4'
 354                                    hash table: do not free() */
 355                                 if (th->nxt == NULL) {
 356                                         th->nxt = (struct tcp_seq_hash *)
 357                                                 calloc(1, sizeof(*th));
 358                                         if (th->nxt == NULL)
 359                                                 (*ndo->ndo_error)(ndo,
 360                                                         S_ERR_ND_MEM_ALLOC,
 361                                                         "%s: calloc", __func__);
 362                                 }
 363                                 th->addr = tha;
 364                                 if (rev)
 365                                         th->ack = seq, th->seq = ack - 1;
 366                                 else
 367                                         th->seq = seq, th->ack = ack - 1;
 368                         } else {
 369                                 if (rev)
 370                                         seq -= th->ack, ack -= th->seq;
 371                                 else
 372                                         seq -= th->seq, ack -= th->ack;
 373                         }
 374
 375                         thseq = th->seq;
 376                         thack = th->ack;
 377                 }
 378         } else {
 379                 /*fool gcc*/
 380                 thseq = thack = rev = 0;
 381         }
 382         if (hlen > length) {
 383                 ND_PRINT(" [bad hdr length %u - too long, > %u]",
 384                          hlen, length);
 385                 goto invalid;
 386         }
 387
 388         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 389                 /* Check the checksum, if possible. */
 390                 uint16_t sum, tcp_sum;
 391
 392                 if (IP_V(ip) == 4) {
 393                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 394                                 sum = tcp_cksum(ndo, ip, tp, length);
 395                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 396
 397                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 398                                 if (sum != 0)
 399                                         ND_PRINT(" (incorrect -> 0x%04x)",
 400                                             in_cksum_shouldbe(tcp_sum, sum));
 401                                 else
 402                                         ND_PRINT(" (correct)");
 403                         }
 404                 } else if (IP_V(ip) == 6) {
 405                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 406                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 407                                 tcp_sum = GET_BE_U_2(tp->th_sum);
 408
 409                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 410                                 if (sum != 0)
 411                                         ND_PRINT(" (incorrect -> 0x%04x)",
 412                                             in_cksum_shouldbe(tcp_sum, sum));
 413                                 else
 414                                         ND_PRINT(" (correct)");
 415
 416                         }
 417                 }
 418         }
 419
 420         length -= hlen;
 421         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 422                 ND_PRINT(", seq %u", seq);
 423
 424                 if (length > 0) {
 425                         ND_PRINT(":%u", seq + length);
 426                 }
 427         }
 428
 429         if (flags & TH_ACK) {
 430                 ND_PRINT(", ack %u", ack);
 431         }
 432
 433         ND_PRINT(", win %u", win);
 434
 435         if (flags & TH_URG)
 436                 ND_PRINT(", urg %u", urp);
 437         /*
 438          * Handle any options.
 439          */
 440         if (hlen > sizeof(*tp)) {
 441                 const u_char *cp;
 442                 u_int i, opt, datalen;
 443                 u_int len;
 444
 445                 hlen -= sizeof(*tp);
 446                 cp = (const u_char *)tp + sizeof(*tp);
 447                 ND_PRINT(", options [");
 448                 while (hlen > 0) {
 449                         if (ch != '\0')
 450                                 ND_PRINT("%c", ch);
 451                         opt = GET_U_1(cp);
 452                         cp++;
 453                         if (ZEROLENOPT(opt))
 454                                 len = 1;
 455                         else {
 456                                 len = GET_U_1(cp);
 457                                 cp++;   /* total including type, len */
 458                                 if (len < 2 || len > hlen)
 459                                         goto bad;
 460                                 --hlen;         /* account for length byte */
 461                         }
 462                         --hlen;                 /* account for type byte */
 463                         datalen = 0;
 464
 465 /* Bail if "l" bytes of data are not left or were not captured  */
 466 #define LENCHECK(l) { if ((l) > hlen) goto bad; }
 467
 468
 469                         ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 470
 471                         switch (opt) {
 472
 473                         case TCPOPT_MAXSEG:
 474                                 datalen = 2;
 475                                 LENCHECK(datalen);
 476                                 ND_PRINT(" %u", GET_BE_U_2(cp));
 477                                 break;
 478
 479                         case TCPOPT_WSCALE:
 480                                 datalen = 1;
 481                                 LENCHECK(datalen);
 482                                 ND_PRINT(" %u", GET_U_1(cp));
 483                                 break;
 484
 485                         case TCPOPT_SACK:
 486                                 datalen = len - 2;
 487                                 if (datalen % 8 != 0) {
 488                                         ND_PRINT(" invalid sack");
 489                                 } else {
 490                                         uint32_t s, e;
 491
 492                                         ND_PRINT(" %u ", datalen / 8);
 493                                         for (i = 0; i < datalen; i += 8) {
 494                                                 LENCHECK(i + 4);
 495                                                 s = GET_BE_U_4(cp + i);
 496                                                 LENCHECK(i + 8);
 497                                                 e = GET_BE_U_4(cp + i + 4);
 498                                                 if (rev) {
 499                                                         s -= thseq;
 500                                                         e -= thseq;
 501                                                 } else {
 502                                                         s -= thack;
 503                                                         e -= thack;
 504                                                 }
 505                                                 ND_PRINT("{%u:%u}", s, e);
 506                                         }
 507                                 }
 508                                 break;
 509
 510                         case TCPOPT_CC:
 511                         case TCPOPT_CCNEW:
 512                         case TCPOPT_CCECHO:
 513                         case TCPOPT_ECHO:
 514                         case TCPOPT_ECHOREPLY:
 515
 516                                 /*
 517                                  * those options share their semantics.
 518                                  * fall through
 519                                  */
 520                                 datalen = 4;
 521                                 LENCHECK(datalen);
 522                                 ND_PRINT(" %u", GET_BE_U_4(cp));
 523                                 break;
 524
 525                         case TCPOPT_TIMESTAMP:
 526                                 datalen = 8;
 527                                 LENCHECK(datalen);
 528                                 ND_PRINT(" val %u ecr %u",
 529                                              GET_BE_U_4(cp),
 530                                              GET_BE_U_4(cp + 4));
 531                                 break;
 532
 533                         case TCPOPT_SIGNATURE:
 534                                 datalen = TCP_SIGLEN;
 535                                 LENCHECK(datalen);
 536                                 ND_TCHECK_LEN(cp, 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                                 /* FIXME: Proof-read mptcp_print() and if it
 625                                  * always covers all bytes when it returns 1,
 626                                  * only do ND_TCHECK_LEN() if it returned 0.
 627                                  */
 628                                 ND_TCHECK_LEN(cp, datalen);
 629                                 /* Update the snapend to the end of the option
 630                                  * before calling mptcp_print(). Some options
 631                                  * (MPTCP or others) may be present after a
 632                                  * MPTCP option. This prevents that, in
 633                                  * mptcp_print(), the remaining length < the
 634                                  * remaining caplen.
 635                                  */
 636                                 snapend_save = ndo->ndo_snapend;
 637                                 ndo->ndo_snapend = ND_MIN(cp - 2 + len,
 638                                                           ndo->ndo_snapend);
 639                                 ret = mptcp_print(ndo, cp - 2, len, flags);
 640                                 ndo->ndo_snapend = snapend_save;
 641                                 if (!ret)
 642                                         goto bad;
 643                                 break;
 644                             }
 645
 646                         case TCPOPT_FASTOPEN:
 647                                 datalen = len - 2;
 648                                 LENCHECK(datalen);
 649                                 ND_TCHECK_LEN(cp, datalen);
 650                                 ND_PRINT(" ");
 651                                 print_tcp_fastopen_option(ndo, cp, datalen);
 652                                 break;
 653
 654                         case TCPOPT_EXPERIMENT2:
 655                                 datalen = len - 2;
 656                                 LENCHECK(datalen);
 657                                 ND_TCHECK_LEN(cp, datalen);
 658                                 if (datalen < 2)
 659                                         goto bad;
 660                                 /* RFC6994 */
 661                                 magic = GET_BE_U_2(cp);
 662                                 ND_PRINT("-");
 663
 664                                 switch(magic) {
 665
 666                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 667                                         ND_PRINT("tfo");
 668                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2);
 669                                         break;
 670
 671                                 default:
 672                                         /* Unknown magic number */
 673                                         ND_PRINT("%04x", magic);
 674                                         break;
 675                                 }
 676                                 break;
 677
 678                         default:
 679                                 datalen = len - 2;
 680                                 if (datalen)
 681                                         ND_PRINT(" 0x");
 682                                 for (i = 0; i < datalen; ++i) {
 683                                         LENCHECK(i + 1);
 684                                         ND_PRINT("%02x", GET_U_1(cp + i));
 685                                 }
 686                                 break;
 687                         }
 688
 689                         /* Account for data printed */
 690                         cp += datalen;
 691                         hlen -= datalen;
 692
 693                         /* Check specification against observed length */
 694                         ++datalen;              /* option octet */
 695                         if (!ZEROLENOPT(opt))
 696                                 ++datalen;      /* size octet */
 697                         if (datalen != len)
 698                                 ND_PRINT("[len %u]", len);
 699                         ch = ',';
 700                         if (opt == TCPOPT_EOL)
 701                                 break;
 702                 }
 703                 ND_PRINT("]");
 704         }
 705
 706         /*
 707          * Print length field before crawling down the stack.
 708          */
 709         ND_PRINT(", length %u", length);
 710
 711         if (length == 0)
 712                 return;
 713
 714         /*
 715          * Decode payload if necessary.
 716          */
 717         header_len = TH_OFF(tp) * 4;
 718         /*
 719          * Do a bounds check before decoding the payload.
 720          * At least the header data is required.
 721          */
 722         if (!ND_TTEST_LEN(bp, header_len)) {
 723                 ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
 724                          ND_BYTES_AVAILABLE_AFTER(bp), header_len);
 725                 nd_trunc_longjmp(ndo);
 726         }
 727         bp += header_len;
 728         if ((flags & TH_RST) && ndo->ndo_vflag) {
 729                 print_tcp_rst_data(ndo, bp, length);
 730                 return;
 731         }
 732
 733         if (ndo->ndo_packettype) {
 734                 switch (ndo->ndo_packettype) {
 735                 case PT_ZMTP1:
 736                         zmtp1_print(ndo, bp, length);
 737                         break;
 738                 case PT_RESP:
 739                         resp_print(ndo, bp, length);
 740                         break;
 741                 case PT_DOMAIN:
 742                         /* over_tcp: TRUE, is_mdns: FALSE */
 743                         domain_print(ndo, bp, length, TRUE, FALSE);
 744                         break;
 745                 }
 746                 return;
 747         }
 748
 749         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 750                 telnet_print(ndo, bp, length);
 751         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 752                 ND_PRINT(": ");
 753                 smtp_print(ndo, bp, length);
 754         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 755                 ND_PRINT(": ");
 756                 whois_print(ndo, bp, length);
 757         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 758                 bgp_print(ndo, bp, length);
 759         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 760                 pptp_print(ndo, bp);
 761         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 762                 resp_print(ndo, bp, length);
 763         else if (IS_SRC_OR_DST_PORT(SSH_PORT))
 764                 ssh_print(ndo, bp, length);
 765 #ifdef ENABLE_SMB
 766         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 767                 nbt_tcp_print(ndo, bp, length);
 768         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 769                 smb_tcp_print(ndo, bp, length);
 770 #endif
 771         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 772                 beep_print(ndo, bp, length);
 773         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 774                 openflow_print(ndo, bp, length);
 775         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 776                 ND_PRINT(": ");
 777                 ftp_print(ndo, bp, length);
 778         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 779                 ND_PRINT(": ");
 780                 http_print(ndo, bp, length);
 781         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 782                 ND_PRINT(": ");
 783                 rtsp_print(ndo, bp, length);
 784         } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) {
 785                 /* over_tcp: TRUE, is_mdns: FALSE */
 786                 domain_print(ndo, bp, length, TRUE, FALSE);
 787         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 788                 msdp_print(ndo, bp, length);
 789         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 790                 rpki_rtr_print(ndo, bp, length);
 791         } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) {
 792                 ldp_print(ndo, bp, length);
 793         } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 794                  length >= 4) {
 795                 /*
 796                  * If data present, header length valid, and NFS port used,
 797                  * assume NFS.
 798                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 799                  * to NFS print routines.
 800                  */
 801                 uint32_t fraglen;
 802                 const struct sunrpc_msg *rp;
 803                 enum sunrpc_msg_type direction;
 804
 805                 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF;
 806                 if (fraglen > (length) - 4)
 807                         fraglen = (length) - 4;
 808                 rp = (const struct sunrpc_msg *)(bp + 4);
 809                 if (ND_TTEST_4(rp->rm_direction)) {
 810                         direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction);
 811                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 812                                 ND_PRINT(": NFS request xid %u ",
 813                                          GET_BE_U_4(rp->rm_xid));
 814                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 815                                 return;
 816                         }
 817                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 818                                 ND_PRINT(": NFS reply xid %u ",
 819                                          GET_BE_U_4(rp->rm_xid));
 820                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 821                                 return;
 822                         }
 823                 }
 824         }
 825
 826         return;
 827 bad:
 828         ND_PRINT("[bad opt]");
 829         if (ch != '\0')
 830                 ND_PRINT("]");
 831         return;
 832 invalid:
 833         nd_print_invalid(ndo);
 834 }
 835
 836 /*
 837  * RFC1122 says the following on data in RST segments:
 838  *
 839  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 840  *
 841  *            A TCP SHOULD allow a received RST segment to include data.
 842  *
 843  *            DISCUSSION
 844  *                 It has been suggested that a RST segment could contain
 845  *                 ASCII text that encoded and explained the cause of the
 846  *                 RST.  No standard has yet been established for such
 847  *                 data.
 848  *
 849  */
 850
 851 static void
 852 print_tcp_rst_data(netdissect_options *ndo,
 853                    const u_char *sp, u_int length)
 854 {
 855         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 856         if (length > MAX_RST_DATA_LEN) {
 857                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 858                 ND_PRINT("+");                  /* indicate we truncate */
 859         }
 860         ND_PRINT(" ");
 861         (void)nd_printn(ndo, sp, length, ndo->ndo_snapend);
 862         ND_PRINT("]");
 863 }
 864
 865 static void
 866 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 867                           u_int datalen)
 868 {
 869         u_int i;
 870
 871         if (datalen == 0) {
 872                 /* Fast Open Cookie Request */
 873                 ND_PRINT(" cookiereq");
 874         } else {
 875                 /* Fast Open Cookie */
 876                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 877                         nd_print_invalid(ndo);
 878                 } else {
 879                         ND_PRINT(" cookie ");
 880                         for (i = 0; i < datalen; ++i)
 881                                 ND_PRINT("%02x", GET_U_1(cp + i));
 882                 }
 883         }
 884 }
 885
 886 #ifdef HAVE_LIBCRYPTO
 887 DIAG_OFF_DEPRECATION
 888 static int
 889 tcp_verify_signature(netdissect_options *ndo,
 890                      const struct ip *ip, const struct tcphdr *tp,
 891                      const u_char *data, u_int length, const u_char *rcvsig)
 892 {
 893         struct tcphdr tp1;
 894         u_char sig[TCP_SIGLEN];
 895         char zero_proto = 0;
 896         MD5_CTX ctx;
 897         uint16_t savecsum, tlen;
 898         const struct ip6_hdr *ip6;
 899         uint32_t len32;
 900         uint8_t nxt;
 901
 902         if (!ND_TTEST_LEN(data, length)) {
 903                 ND_PRINT("snaplen too short, ");
 904                 return (CANT_CHECK_SIGNATURE);
 905         }
 906
 907         tp1 = *tp;
 908
 909         if (ndo->ndo_sigsecret == NULL) {
 910                 ND_PRINT("shared secret not supplied with -M, ");
 911                 return (CANT_CHECK_SIGNATURE);
 912         }
 913
 914         MD5_Init(&ctx);
 915         /*
 916          * Step 1: Update MD5 hash with IP pseudo-header.
 917          */
 918         if (IP_V(ip) == 4) {
 919                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 920                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 921                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 922                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 923                 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 924                 tlen = htons(tlen);
 925                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 926         } else if (IP_V(ip) == 6) {
 927                 ip6 = (const struct ip6_hdr *)ip;
 928                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 929                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 930                 len32 = htonl(GET_BE_U_2(ip6->ip6_plen));
 931                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 932                 nxt = 0;
 933                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 934                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 935                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 936                 nxt = IPPROTO_TCP;
 937                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 938         } else {
 939                 ND_PRINT("IP version not 4 or 6, ");
 940                 return (CANT_CHECK_SIGNATURE);
 941         }
 942
 943         /*
 944          * Step 2: Update MD5 hash with TCP header, excluding options.
 945          * The TCP checksum must be set to zero.
 946          */
 947         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 948         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 949         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 950         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 951         /*
 952          * Step 3: Update MD5 hash with TCP segment data, if present.
 953          */
 954         if (length > 0)
 955                 MD5_Update(&ctx, data, length);
 956         /*
 957          * Step 4: Update MD5 hash with shared secret.
 958          */
 959         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 960         MD5_Final(sig, &ctx);
 961
 962         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 963                 return (SIGNATURE_VALID);
 964         else
 965                 return (SIGNATURE_INVALID);
 966 }
 967 DIAG_ON_DEPRECATION
 968 #endif /* HAVE_LIBCRYPTO */