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         tp = (const struct tcphdr *)bp;
 177         ip = (const struct ip *)bp2;
 178         if (IP_V(ip) == 6)
 179                 ip6 = (const struct ip6_hdr *)bp2;
 180         else
 181                 ip6 = NULL;
 182         ch = '\0';
 183         if (!ND_TTEST_2(tp->th_dport)) {
 184                 if (ip6) {
 185                         ND_PRINT("%s > %s: ",
 186                                      ip6addr_string(ndo, ip6->ip6_src),
 187                                      ip6addr_string(ndo, ip6->ip6_dst));
 188                 } else {
 189                         ND_PRINT("%s > %s: [|tcp]",
 190                                      ipaddr_string(ndo, ip->ip_src),
 191                                      ipaddr_string(ndo, ip->ip_dst));
 192                 }
 193                 return;
 194         }
 195
 196         sport = EXTRACT_BE_U_2(tp->th_sport);
 197         dport = EXTRACT_BE_U_2(tp->th_dport);
 198
 199         if (ip6) {
 200                 if (EXTRACT_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
 201                         ND_PRINT("%s.%s > %s.%s: ",
 202                                      ip6addr_string(ndo, ip6->ip6_src),
 203                                      tcpport_string(ndo, sport),
 204                                      ip6addr_string(ndo, ip6->ip6_dst),
 205                                      tcpport_string(ndo, dport));
 206                 } else {
 207                         ND_PRINT("%s > %s: ",
 208                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 209                 }
 210         } else {
 211                 if (EXTRACT_U_1(ip->ip_p) == IPPROTO_TCP) {
 212                         ND_PRINT("%s.%s > %s.%s: ",
 213                                      ipaddr_string(ndo, ip->ip_src),
 214                                      tcpport_string(ndo, sport),
 215                                      ipaddr_string(ndo, ip->ip_dst),
 216                                      tcpport_string(ndo, dport));
 217                 } else {
 218                         ND_PRINT("%s > %s: ",
 219                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport));
 220                 }
 221         }
 222
 223         ND_TCHECK_SIZE(tp);
 224
 225         hlen = TH_OFF(tp) * 4;
 226
 227         if (hlen < sizeof(*tp)) {
 228                 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %lu]",
 229                              length - hlen, hlen, (unsigned long)sizeof(*tp));
 230                 return;
 231         }
 232
 233         seq = EXTRACT_BE_U_4(tp->th_seq);
 234         ack = EXTRACT_BE_U_4(tp->th_ack);
 235         win = EXTRACT_BE_U_2(tp->th_win);
 236         urp = EXTRACT_BE_U_2(tp->th_urp);
 237
 238         if (ndo->ndo_qflag) {
 239                 ND_PRINT("tcp %u", length - hlen);
 240                 if (hlen > length) {
 241                         ND_PRINT(" [bad hdr length %u - too long, > %u]",
 242                                      hlen, length);
 243                 }
 244                 return;
 245         }
 246
 247         flags = EXTRACT_U_1(tp->th_flags);
 248         ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
 249
 250         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 251                 /*
 252                  * Find (or record) the initial sequence numbers for
 253                  * this conversation.  (we pick an arbitrary
 254                  * collating order so there's only one entry for
 255                  * both directions).
 256                  */
 257                 rev = 0;
 258                 if (ip6) {
 259                         struct tcp_seq_hash6 *th;
 260                         struct tcp_seq_hash6 *tcp_seq_hash;
 261                         const void *src, *dst;
 262                         struct tha6 tha;
 263
 264                         tcp_seq_hash = tcp_seq_hash6;
 265                         src = (const void *)&ip6->ip6_src;
 266                         dst = (const void *)&ip6->ip6_dst;
 267                         if (sport > dport)
 268                                 rev = 1;
 269                         else if (sport == dport) {
 270                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 271                                         rev = 1;
 272                         }
 273                         if (rev) {
 274                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 275                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 276                                 tha.port = dport << 16 | sport;
 277                         } else {
 278                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 279                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 280                                 tha.port = sport << 16 | dport;
 281                         }
 282
 283                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 284                              th->nxt; th = th->nxt)
 285                                 if (memcmp((char *)&tha, (char *)&th->addr,
 286                                            sizeof(th->addr)) == 0)
 287                                         break;
 288
 289                         if (!th->nxt || (flags & TH_SYN)) {
 290                                 /* didn't find it or new conversation */
 291                                 if (th->nxt == NULL) {
 292                                         th->nxt = (struct tcp_seq_hash6 *)
 293                                                 calloc(1, sizeof(*th));
 294                                         if (th->nxt == NULL)
 295                                                 (*ndo->ndo_error)(ndo,
 296                                                                   "tcp_print: calloc");
 297                                 }
 298                                 th->addr = tha;
 299                                 if (rev)
 300                                         th->ack = seq, th->seq = ack - 1;
 301                                 else
 302                                         th->seq = seq, th->ack = ack - 1;
 303                         } else {
 304                                 if (rev)
 305                                         seq -= th->ack, ack -= th->seq;
 306                                 else
 307                                         seq -= th->seq, ack -= th->ack;
 308                         }
 309
 310                         thseq = th->seq;
 311                         thack = th->ack;
 312                 } else {
 313                         struct tcp_seq_hash *th;
 314                         struct tcp_seq_hash *tcp_seq_hash;
 315                         struct tha tha;
 316
 317                         tcp_seq_hash = tcp_seq_hash4;
 318                         if (sport > dport)
 319                                 rev = 1;
 320                         else if (sport == dport) {
 321                                 if (UNALIGNED_MEMCMP(&ip->ip_src, &ip->ip_dst, sizeof ip->ip_dst) > 0)
 322                                         rev = 1;
 323                         }
 324                         if (rev) {
 325                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_dst, sizeof ip->ip_dst);
 326                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_src, sizeof ip->ip_src);
 327                                 tha.port = dport << 16 | sport;
 328                         } else {
 329                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_dst, sizeof ip->ip_dst);
 330                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_src, sizeof ip->ip_src);
 331                                 tha.port = sport << 16 | dport;
 332                         }
 333
 334                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 335                              th->nxt; th = th->nxt)
 336                                 if (memcmp((char *)&tha, (char *)&th->addr,
 337                                            sizeof(th->addr)) == 0)
 338                                         break;
 339
 340                         if (!th->nxt || (flags & TH_SYN)) {
 341                                 /* didn't find it or new conversation */
 342                                 if (th->nxt == NULL) {
 343                                         th->nxt = (struct tcp_seq_hash *)
 344                                                 calloc(1, sizeof(*th));
 345                                         if (th->nxt == NULL)
 346                                                 (*ndo->ndo_error)(ndo,
 347                                                                   "tcp_print: calloc");
 348                                 }
 349                                 th->addr = tha;
 350                                 if (rev)
 351                                         th->ack = seq, th->seq = ack - 1;
 352                                 else
 353                                         th->seq = seq, th->ack = ack - 1;
 354                         } else {
 355                                 if (rev)
 356                                         seq -= th->ack, ack -= th->seq;
 357                                 else
 358                                         seq -= th->seq, ack -= th->ack;
 359                         }
 360
 361                         thseq = th->seq;
 362                         thack = th->ack;
 363                 }
 364         } else {
 365                 /*fool gcc*/
 366                 thseq = thack = rev = 0;
 367         }
 368         if (hlen > length) {
 369                 ND_PRINT(" [bad hdr length %u - too long, > %u]",
 370                              hlen, length);
 371                 return;
 372         }
 373
 374         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 375                 /* Check the checksum, if possible. */
 376                 uint16_t sum, tcp_sum;
 377
 378                 if (IP_V(ip) == 4) {
 379                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 380                                 sum = tcp_cksum(ndo, ip, tp, length);
 381                                 tcp_sum = EXTRACT_BE_U_2(tp->th_sum);
 382
 383                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 384                                 if (sum != 0)
 385                                         ND_PRINT(" (incorrect -> 0x%04x)",
 386                                             in_cksum_shouldbe(tcp_sum, sum));
 387                                 else
 388                                         ND_PRINT(" (correct)");
 389                         }
 390                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 391                         if (ND_TTEST_LEN(tp->th_sport, length)) {
 392                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 393                                 tcp_sum = EXTRACT_BE_U_2(tp->th_sum);
 394
 395                                 ND_PRINT(", cksum 0x%04x", tcp_sum);
 396                                 if (sum != 0)
 397                                         ND_PRINT(" (incorrect -> 0x%04x)",
 398                                             in_cksum_shouldbe(tcp_sum, sum));
 399                                 else
 400                                         ND_PRINT(" (correct)");
 401
 402                         }
 403                 }
 404         }
 405
 406         length -= hlen;
 407         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 408                 ND_PRINT(", seq %u", seq);
 409
 410                 if (length > 0) {
 411                         ND_PRINT(":%u", seq + length);
 412                 }
 413         }
 414
 415         if (flags & TH_ACK) {
 416                 ND_PRINT(", ack %u", ack);
 417         }
 418
 419         ND_PRINT(", win %u", win);
 420
 421         if (flags & TH_URG)
 422                 ND_PRINT(", urg %u", urp);
 423         /*
 424          * Handle any options.
 425          */
 426         if (hlen > sizeof(*tp)) {
 427                 const u_char *cp;
 428                 u_int i, opt, datalen;
 429                 u_int len;
 430
 431                 hlen -= sizeof(*tp);
 432                 cp = (const u_char *)tp + sizeof(*tp);
 433                 ND_PRINT(", options [");
 434                 while (hlen > 0) {
 435                         if (ch != '\0')
 436                                 ND_PRINT("%c", ch);
 437                         ND_TCHECK_1(cp);
 438                         opt = EXTRACT_U_1(cp);
 439                         cp++;
 440                         if (ZEROLENOPT(opt))
 441                                 len = 1;
 442                         else {
 443                                 ND_TCHECK_1(cp);
 444                                 len = EXTRACT_U_1(cp);
 445                                 cp++;   /* total including type, len */
 446                                 if (len < 2 || len > hlen)
 447                                         goto bad;
 448                                 --hlen;         /* account for length byte */
 449                         }
 450                         --hlen;                 /* account for type byte */
 451                         datalen = 0;
 452
 453 /* Bail if "l" bytes of data are not left or were not captured  */
 454 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK_LEN(cp, l); }
 455
 456
 457                         ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
 458
 459                         switch (opt) {
 460
 461                         case TCPOPT_MAXSEG:
 462                                 datalen = 2;
 463                                 LENCHECK(datalen);
 464                                 ND_PRINT(" %u", EXTRACT_BE_U_2(cp));
 465                                 break;
 466
 467                         case TCPOPT_WSCALE:
 468                                 datalen = 1;
 469                                 LENCHECK(datalen);
 470                                 ND_PRINT(" %u", EXTRACT_U_1(cp));
 471                                 break;
 472
 473                         case TCPOPT_SACK:
 474                                 datalen = len - 2;
 475                                 if (datalen % 8 != 0) {
 476                                         ND_PRINT(" invalid sack");
 477                                 } else {
 478                                         uint32_t s, e;
 479
 480                                         ND_PRINT(" %u ", datalen / 8);
 481                                         for (i = 0; i < datalen; i += 8) {
 482                                                 LENCHECK(i + 4);
 483                                                 s = EXTRACT_BE_U_4(cp + i);
 484                                                 LENCHECK(i + 8);
 485                                                 e = EXTRACT_BE_U_4(cp + i + 4);
 486                                                 if (rev) {
 487                                                         s -= thseq;
 488                                                         e -= thseq;
 489                                                 } else {
 490                                                         s -= thack;
 491                                                         e -= thack;
 492                                                 }
 493                                                 ND_PRINT("{%u:%u}", s, e);
 494                                         }
 495                                 }
 496                                 break;
 497
 498                         case TCPOPT_CC:
 499                         case TCPOPT_CCNEW:
 500                         case TCPOPT_CCECHO:
 501                         case TCPOPT_ECHO:
 502                         case TCPOPT_ECHOREPLY:
 503
 504                                 /*
 505                                  * those options share their semantics.
 506                                  * fall through
 507                                  */
 508                                 datalen = 4;
 509                                 LENCHECK(datalen);
 510                                 ND_PRINT(" %u", EXTRACT_BE_U_4(cp));
 511                                 break;
 512
 513                         case TCPOPT_TIMESTAMP:
 514                                 datalen = 8;
 515                                 LENCHECK(datalen);
 516                                 ND_PRINT(" val %u ecr %u",
 517                                              EXTRACT_BE_U_4(cp),
 518                                              EXTRACT_BE_U_4(cp + 4));
 519                                 break;
 520
 521                         case TCPOPT_SIGNATURE:
 522                                 datalen = TCP_SIGLEN;
 523                                 LENCHECK(datalen);
 524                                 ND_PRINT(" ");
 525 #ifdef HAVE_LIBCRYPTO
 526                                 switch (tcp_verify_signature(ndo, ip, tp,
 527                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 528
 529                                 case SIGNATURE_VALID:
 530                                         ND_PRINT("valid");
 531                                         break;
 532
 533                                 case SIGNATURE_INVALID:
 534                                         ND_PRINT("invalid");
 535                                         break;
 536
 537                                 case CANT_CHECK_SIGNATURE:
 538                                         ND_PRINT("can't check - ");
 539                                         for (i = 0; i < TCP_SIGLEN; ++i)
 540                                                 ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 541                                         break;
 542                                 }
 543 #else
 544                                 for (i = 0; i < TCP_SIGLEN; ++i)
 545                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 546 #endif
 547                                 break;
 548
 549                         case TCPOPT_SCPS:
 550                                 datalen = 2;
 551                                 LENCHECK(datalen);
 552                                 ND_PRINT(" cap %02x id %u", EXTRACT_U_1(cp), EXTRACT_U_1(cp + 1));
 553                                 break;
 554
 555                         case TCPOPT_TCPAO:
 556                                 datalen = len - 2;
 557                                 /* RFC 5925 Section 2.2:
 558                                  * "The Length value MUST be greater than or equal to 4."
 559                                  * (This includes the Kind and Length fields already processed
 560                                  * at this point.)
 561                                  */
 562                                 if (datalen < 2) {
 563                                         ND_PRINT(" invalid");
 564                                 } else {
 565                                         LENCHECK(1);
 566                                         ND_PRINT(" keyid %u", EXTRACT_U_1(cp));
 567                                         LENCHECK(2);
 568                                         ND_PRINT(" rnextkeyid %u", EXTRACT_U_1(cp + 1));
 569                                         if (datalen > 2) {
 570                                                 ND_PRINT(" mac 0x");
 571                                                 for (i = 2; i < datalen; i++) {
 572                                                         LENCHECK(i + 1);
 573                                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 574                                                 }
 575                                         }
 576                                 }
 577                                 break;
 578
 579                         case TCPOPT_EOL:
 580                         case TCPOPT_NOP:
 581                         case TCPOPT_SACKOK:
 582                                 /*
 583                                  * Nothing interesting.
 584                                  * fall through
 585                                  */
 586                                 break;
 587
 588                         case TCPOPT_UTO:
 589                                 datalen = 2;
 590                                 LENCHECK(datalen);
 591                                 utoval = EXTRACT_BE_U_2(cp);
 592                                 ND_PRINT(" 0x%x", utoval);
 593                                 if (utoval & 0x0001)
 594                                         utoval = (utoval >> 1) * 60;
 595                                 else
 596                                         utoval >>= 1;
 597                                 ND_PRINT(" %u", utoval);
 598                                 break;
 599
 600                         case TCPOPT_MPTCP:
 601                                 datalen = len - 2;
 602                                 LENCHECK(datalen);
 603                                 if (!mptcp_print(ndo, cp-2, len, flags))
 604                                         goto bad;
 605                                 break;
 606
 607                         case TCPOPT_FASTOPEN:
 608                                 datalen = len - 2;
 609                                 LENCHECK(datalen);
 610                                 ND_PRINT(" ");
 611                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 612                                 break;
 613
 614                         case TCPOPT_EXPERIMENT2:
 615                                 datalen = len - 2;
 616                                 LENCHECK(datalen);
 617                                 if (datalen < 2)
 618                                         goto bad;
 619                                 /* RFC6994 */
 620                                 magic = EXTRACT_BE_U_2(cp);
 621                                 ND_PRINT("-");
 622
 623                                 switch(magic) {
 624
 625                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 626                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 627                                         break;
 628
 629                                 default:
 630                                         /* Unknown magic number */
 631                                         ND_PRINT("%04x", magic);
 632                                         break;
 633                                 }
 634                                 break;
 635
 636                         default:
 637                                 datalen = len - 2;
 638                                 if (datalen)
 639                                         ND_PRINT(" 0x");
 640                                 for (i = 0; i < datalen; ++i) {
 641                                         LENCHECK(i + 1);
 642                                         ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 643                                 }
 644                                 break;
 645                         }
 646
 647                         /* Account for data printed */
 648                         cp += datalen;
 649                         hlen -= datalen;
 650
 651                         /* Check specification against observed length */
 652                         ++datalen;                      /* option octet */
 653                         if (!ZEROLENOPT(opt))
 654                                 ++datalen;              /* size octet */
 655                         if (datalen != len)
 656                                 ND_PRINT("[len %u]", len);
 657                         ch = ',';
 658                         if (opt == TCPOPT_EOL)
 659                                 break;
 660                 }
 661                 ND_PRINT("]");
 662         }
 663
 664         /*
 665          * Print length field before crawling down the stack.
 666          */
 667         ND_PRINT(", length %u", length);
 668
 669         if (length <= 0)
 670                 return;
 671
 672         /*
 673          * Decode payload if necessary.
 674          */
 675         bp += TH_OFF(tp) * 4;
 676         if ((flags & TH_RST) && ndo->ndo_vflag) {
 677                 print_tcp_rst_data(ndo, bp, length);
 678                 return;
 679         }
 680
 681         if (ndo->ndo_packettype) {
 682                 switch (ndo->ndo_packettype) {
 683                 case PT_ZMTP1:
 684                         zmtp1_print(ndo, bp, length);
 685                         break;
 686                 case PT_RESP:
 687                         resp_print(ndo, bp, length);
 688                         break;
 689                 }
 690                 return;
 691         }
 692
 693         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 694                 telnet_print(ndo, bp, length);
 695         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 696                 ND_PRINT(": ");
 697                 smtp_print(ndo, bp, length);
 698         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 699                 ND_PRINT(": ");
 700                 txtproto_print(ndo, bp, length, "whois", NULL, 0); /* RFC 3912 */
 701         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 702                 bgp_print(ndo, bp, length);
 703         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 704                 pptp_print(ndo, bp);
 705         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 706                 resp_print(ndo, bp, length);
 707 #ifdef ENABLE_SMB
 708         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 709                 nbt_tcp_print(ndo, bp, length);
 710         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 711                 smb_tcp_print(ndo, bp, length);
 712 #endif
 713         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 714                 beep_print(ndo, bp, length);
 715         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 716                 openflow_print(ndo, bp, length);
 717         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 718                 ND_PRINT(": ");
 719                 ftp_print(ndo, bp, length);
 720         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 721                 ND_PRINT(": ");
 722                 http_print(ndo, bp, length);
 723         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 724                 ND_PRINT(": ");
 725                 rtsp_print(ndo, bp, length);
 726         } else if (length > 2 &&
 727                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 728                 /*
 729                  * TCP DNS query has 2byte length at the head.
 730                  * XXX packet could be unaligned, it can go strange
 731                  */
 732                 domain_print(ndo, bp + 2, length - 2, 0);
 733         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 734                 msdp_print(ndo, bp, length);
 735         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 736                 rpki_rtr_print(ndo, bp, length);
 737         }
 738         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 739                 ldp_print(ndo, bp, length);
 740         }
 741         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 742                  length >= 4 && ND_TTEST_4(bp)) {
 743                 /*
 744                  * If data present, header length valid, and NFS port used,
 745                  * assume NFS.
 746                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 747                  * to NFS print routines.
 748                  */
 749                 uint32_t fraglen;
 750                 const struct sunrpc_msg *rp;
 751                 enum sunrpc_msg_type direction;
 752
 753                 fraglen = EXTRACT_BE_U_4(bp) & 0x7FFFFFFF;
 754                 if (fraglen > (length) - 4)
 755                         fraglen = (length) - 4;
 756                 rp = (const struct sunrpc_msg *)(bp + 4);
 757                 if (ND_TTEST_4(rp->rm_direction)) {
 758                         direction = (enum sunrpc_msg_type) EXTRACT_BE_U_4(rp->rm_direction);
 759                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 760                                 ND_PRINT(": NFS request xid %u ",
 761                                          EXTRACT_BE_U_4(rp->rm_xid));
 762                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 763                                 return;
 764                         }
 765                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 766                                 ND_PRINT(": NFS reply xid %u ",
 767                                          EXTRACT_BE_U_4(rp->rm_xid));
 768                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 769                                 return;
 770                         }
 771                 }
 772         }
 773
 774         return;
 775  bad:
 776         ND_PRINT("[bad opt]");
 777         if (ch != '\0')
 778                 ND_PRINT(">");
 779         return;
 780  trunc:
 781         ND_PRINT("[|tcp]");
 782         if (ch != '\0')
 783                 ND_PRINT(">");
 784 }
 785
 786 /*
 787  * RFC1122 says the following on data in RST segments:
 788  *
 789  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 790  *
 791  *            A TCP SHOULD allow a received RST segment to include data.
 792  *
 793  *            DISCUSSION
 794  *                 It has been suggested that a RST segment could contain
 795  *                 ASCII text that encoded and explained the cause of the
 796  *                 RST.  No standard has yet been established for such
 797  *                 data.
 798  *
 799  */
 800
 801 static void
 802 print_tcp_rst_data(netdissect_options *ndo,
 803                    const u_char *sp, u_int length)
 804 {
 805         int c;
 806
 807         ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
 808         if (length > MAX_RST_DATA_LEN) {
 809                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 810                 ND_PRINT("+");                  /* indicate we truncate */
 811         }
 812         ND_PRINT(" ");
 813         while (length-- && sp < ndo->ndo_snapend) {
 814                 c = EXTRACT_U_1(sp);
 815                 sp++;
 816                 safeputchar(ndo, c);
 817         }
 818         ND_PRINT("]");
 819 }
 820
 821 static void
 822 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
 823                           u_int datalen, int exp)
 824 {
 825         u_int i;
 826
 827         if (exp)
 828                 ND_PRINT("tfo");
 829
 830         if (datalen == 0) {
 831                 /* Fast Open Cookie Request */
 832                 ND_PRINT(" cookiereq");
 833         } else {
 834                 /* Fast Open Cookie */
 835                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 836                         ND_PRINT(" invalid");
 837                 } else {
 838                         ND_PRINT(" cookie ");
 839                         for (i = 0; i < datalen; ++i)
 840                                 ND_PRINT("%02x", EXTRACT_U_1(cp + i));
 841                 }
 842         }
 843 }
 844
 845 #ifdef HAVE_LIBCRYPTO
 846 USES_APPLE_DEPRECATED_API
 847 static int
 848 tcp_verify_signature(netdissect_options *ndo,
 849                      const struct ip *ip, const struct tcphdr *tp,
 850                      const u_char *data, u_int length, const u_char *rcvsig)
 851 {
 852         struct tcphdr tp1;
 853         u_char sig[TCP_SIGLEN];
 854         char zero_proto = 0;
 855         MD5_CTX ctx;
 856         uint16_t savecsum, tlen;
 857         const struct ip6_hdr *ip6;
 858         uint32_t len32;
 859         uint8_t nxt;
 860
 861         if (data + length > ndo->ndo_snapend) {
 862                 ND_PRINT("snaplen too short, ");
 863                 return (CANT_CHECK_SIGNATURE);
 864         }
 865
 866         tp1 = *tp;
 867
 868         if (ndo->ndo_sigsecret == NULL) {
 869                 ND_PRINT("shared secret not supplied with -M, ");
 870                 return (CANT_CHECK_SIGNATURE);
 871         }
 872
 873         MD5_Init(&ctx);
 874         /*
 875          * Step 1: Update MD5 hash with IP pseudo-header.
 876          */
 877         if (IP_V(ip) == 4) {
 878                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 879                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 880                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 881                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 882                 tlen = EXTRACT_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
 883                 tlen = htons(tlen);
 884                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 885         } else if (IP_V(ip) == 6) {
 886                 ip6 = (const struct ip6_hdr *)ip;
 887                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 888                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 889                 len32 = htonl(EXTRACT_BE_U_2(ip6->ip6_plen));
 890                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 891                 nxt = 0;
 892                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 893                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 894                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 895                 nxt = IPPROTO_TCP;
 896                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 897         } else {
 898                 ND_PRINT("IP version not 4 or 6, ");
 899                 return (CANT_CHECK_SIGNATURE);
 900         }
 901
 902         /*
 903          * Step 2: Update MD5 hash with TCP header, excluding options.
 904          * The TCP checksum must be set to zero.
 905          */
 906         memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
 907         memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
 908         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 909         memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
 910         /*
 911          * Step 3: Update MD5 hash with TCP segment data, if present.
 912          */
 913         if (length > 0)
 914                 MD5_Update(&ctx, data, length);
 915         /*
 916          * Step 4: Update MD5 hash with shared secret.
 917          */
 918         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 919         MD5_Final(sig, &ctx);
 920
 921         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 922                 return (SIGNATURE_VALID);
 923         else
 924                 return (SIGNATURE_INVALID);
 925 }
 926 USES_APPLE_RST
 927 #endif /* HAVE_LIBCRYPTO */
 928
 929 /*
 930  * Local Variables:
 931  * c-style: whitesmith
 932  * c-basic-offset: 8
 933  * End:
 934  */