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 #ifndef lint
  27 #else
  28 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
  29 #endif
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <tcpdump-stdinc.h>
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39
  40 #include "netdissect.h"
  41 #include "addrtoname.h"
  42 #include "extract.h"
  43
  44 #include "tcp.h"
  45
  46 #include "ip.h"
  47 #ifdef INET6
  48 #include "ip6.h"
  49 #endif
  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, int length, const u_char *rcvsig);
  61 #endif
  62
  63 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
  64 static void print_tcp_fastopen_option(netdissect_options *ndo, register 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         tcp_seq seq;
  80         tcp_seq ack;
  81 };
  82
  83 #ifdef INET6
  84 struct tha6 {
  85         struct in6_addr src;
  86         struct in6_addr dst;
  87         u_int port;
  88 };
  89
  90 struct tcp_seq_hash6 {
  91         struct tcp_seq_hash6 *nxt;
  92         struct tha6 addr;
  93         tcp_seq seq;
  94         tcp_seq ack;
  95 };
  96 #endif
  97
  98 #define TSEQ_HASHSIZE 919
  99
 100 /* These tcp optinos 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 #ifdef INET6
 105 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 106 #endif
 107
 108 static const struct tok tcp_flag_values[] = {
 109         { TH_FIN, "F" },
 110         { TH_SYN, "S" },
 111         { TH_RST, "R" },
 112         { TH_PUSH, "P" },
 113         { TH_ACK, "." },
 114         { TH_URG, "U" },
 115         { TH_ECNECHO, "E" },
 116         { TH_CWR, "W" },
 117         { 0, NULL }
 118 };
 119
 120 static const struct tok tcp_option_values[] = {
 121         { TCPOPT_EOL, "eol" },
 122         { TCPOPT_NOP, "nop" },
 123         { TCPOPT_MAXSEG, "mss" },
 124         { TCPOPT_WSCALE, "wscale" },
 125         { TCPOPT_SACKOK, "sackOK" },
 126         { TCPOPT_SACK, "sack" },
 127         { TCPOPT_ECHO, "echo" },
 128         { TCPOPT_ECHOREPLY, "echoreply" },
 129         { TCPOPT_TIMESTAMP, "TS" },
 130         { TCPOPT_CC, "cc" },
 131         { TCPOPT_CCNEW, "ccnew" },
 132         { TCPOPT_CCECHO, "" },
 133         { TCPOPT_SIGNATURE, "md5" },
 134         { TCPOPT_AUTH, "enhanced auth" },
 135         { TCPOPT_UTO, "uto" },
 136         { TCPOPT_MPTCP, "mptcp" },
 137         { TCPOPT_FASTOPEN, "tfo" },
 138         { TCPOPT_EXPERIMENT2, "exp" },
 139         { 0, NULL }
 140 };
 141
 142 static int
 143 tcp_cksum(netdissect_options *ndo,
 144           register const struct ip *ip,
 145           register const struct tcphdr *tp,
 146           register u_int len)
 147 {
 148         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 149                                 IPPROTO_TCP);
 150 }
 151
 152 void
 153 tcp_print(netdissect_options *ndo,
 154           register const u_char *bp, register u_int length,
 155           register const u_char *bp2, int fragmented)
 156 {
 157         register const struct tcphdr *tp;
 158         register const struct ip *ip;
 159         register u_char flags;
 160         register u_int hlen;
 161         register char ch;
 162         uint16_t sport, dport, win, urp;
 163         uint32_t seq, ack, thseq, thack;
 164         u_int utoval;
 165         uint16_t magic;
 166         register int rev;
 167 #ifdef INET6
 168         register const struct ip6_hdr *ip6;
 169 #endif
 170
 171         tp = (const struct tcphdr *)bp;
 172         ip = (const struct ip *)bp2;
 173 #ifdef INET6
 174         if (IP_V(ip) == 6)
 175                 ip6 = (const struct ip6_hdr *)bp2;
 176         else
 177                 ip6 = NULL;
 178 #endif /*INET6*/
 179         ch = '\0';
 180         if (!ND_TTEST(tp->th_dport)) {
 181                 ND_PRINT((ndo, "%s > %s: [|tcp]",
 182                              ipaddr_string(ndo, &ip->ip_src),
 183                              ipaddr_string(ndo, &ip->ip_dst)));
 184                 return;
 185         }
 186
 187         sport = EXTRACT_16BITS(&tp->th_sport);
 188         dport = EXTRACT_16BITS(&tp->th_dport);
 189
 190         hlen = TH_OFF(tp) * 4;
 191
 192 #ifdef INET6
 193         if (ip6) {
 194                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 195                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 196                                      ip6addr_string(ndo, &ip6->ip6_src),
 197                                      tcpport_string(ndo, sport),
 198                                      ip6addr_string(ndo, &ip6->ip6_dst),
 199                                      tcpport_string(ndo, dport)));
 200                 } else {
 201                         ND_PRINT((ndo, "%s > %s: ",
 202                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 203                 }
 204         } else
 205 #endif /*INET6*/
 206         {
 207                 if (ip->ip_p == IPPROTO_TCP) {
 208                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 209                                      ipaddr_string(ndo, &ip->ip_src),
 210                                      tcpport_string(ndo, sport),
 211                                      ipaddr_string(ndo, &ip->ip_dst),
 212                                      tcpport_string(ndo, dport)));
 213                 } else {
 214                         ND_PRINT((ndo, "%s > %s: ",
 215                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 216                 }
 217         }
 218
 219         if (hlen < sizeof(*tp)) {
 220                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 221                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 222                 return;
 223         }
 224
 225         ND_TCHECK(*tp);
 226
 227         seq = EXTRACT_32BITS(&tp->th_seq);
 228         ack = EXTRACT_32BITS(&tp->th_ack);
 229         win = EXTRACT_16BITS(&tp->th_win);
 230         urp = EXTRACT_16BITS(&tp->th_urp);
 231
 232         if (ndo->ndo_qflag) {
 233                 ND_PRINT((ndo, "tcp %d", length - hlen));
 234                 if (hlen > length) {
 235                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 236                                      hlen, length));
 237                 }
 238                 return;
 239         }
 240
 241         flags = tp->th_flags;
 242         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
 243
 244         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 245                 /*
 246                  * Find (or record) the initial sequence numbers for
 247                  * this conversation.  (we pick an arbitrary
 248                  * collating order so there's only one entry for
 249                  * both directions).
 250                  */
 251                 rev = 0;
 252 #ifdef INET6
 253                 if (ip6) {
 254                         register struct tcp_seq_hash6 *th;
 255                         struct tcp_seq_hash6 *tcp_seq_hash;
 256                         const struct in6_addr *src, *dst;
 257                         struct tha6 tha;
 258
 259                         tcp_seq_hash = tcp_seq_hash6;
 260                         src = &ip6->ip6_src;
 261                         dst = &ip6->ip6_dst;
 262                         if (sport > dport)
 263                                 rev = 1;
 264                         else if (sport == dport) {
 265                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 266                                         rev = 1;
 267                         }
 268                         if (rev) {
 269                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 270                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 271                                 tha.port = dport << 16 | sport;
 272                         } else {
 273                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 274                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 275                                 tha.port = sport << 16 | dport;
 276                         }
 277
 278                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 279                              th->nxt; th = th->nxt)
 280                                 if (memcmp((char *)&tha, (char *)&th->addr,
 281                                            sizeof(th->addr)) == 0)
 282                                         break;
 283
 284                         if (!th->nxt || (flags & TH_SYN)) {
 285                                 /* didn't find it or new conversation */
 286                                 if (th->nxt == NULL) {
 287                                         th->nxt = (struct tcp_seq_hash6 *)
 288                                                 calloc(1, sizeof(*th));
 289                                         if (th->nxt == NULL)
 290                                                 (*ndo->ndo_error)(ndo,
 291                                                                   "tcp_print: calloc");
 292                                 }
 293                                 th->addr = tha;
 294                                 if (rev)
 295                                         th->ack = seq, th->seq = ack - 1;
 296                                 else
 297                                         th->seq = seq, th->ack = ack - 1;
 298                         } else {
 299                                 if (rev)
 300                                         seq -= th->ack, ack -= th->seq;
 301                                 else
 302                                         seq -= th->seq, ack -= th->ack;
 303                         }
 304
 305                         thseq = th->seq;
 306                         thack = th->ack;
 307                 } else {
 308 #else  /*INET6*/
 309                 {
 310 #endif /*INET6*/
 311                         register struct tcp_seq_hash *th;
 312                         struct tcp_seq_hash *tcp_seq_hash;
 313                         const struct in_addr *src, *dst;
 314                         struct tha tha;
 315
 316                         tcp_seq_hash = tcp_seq_hash4;
 317                         src = &ip->ip_src;
 318                         dst = &ip->ip_dst;
 319                         if (sport > dport)
 320                                 rev = 1;
 321                         else if (sport == dport) {
 322                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip->ip_dst) > 0)
 323                                         rev = 1;
 324                         }
 325                         if (rev) {
 326                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip->ip_dst);
 327                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip->ip_src);
 328                                 tha.port = dport << 16 | sport;
 329                         } else {
 330                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip->ip_dst);
 331                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip->ip_src);
 332                                 tha.port = sport << 16 | dport;
 333                         }
 334
 335                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 336                              th->nxt; th = th->nxt)
 337                                 if (memcmp((char *)&tha, (char *)&th->addr,
 338                                            sizeof(th->addr)) == 0)
 339                                         break;
 340
 341                         if (!th->nxt || (flags & TH_SYN)) {
 342                                 /* didn't find it or new conversation */
 343                                 if (th->nxt == NULL) {
 344                                         th->nxt = (struct tcp_seq_hash *)
 345                                                 calloc(1, sizeof(*th));
 346                                         if (th->nxt == NULL)
 347                                                 (*ndo->ndo_error)(ndo,
 348                                                                   "tcp_print: calloc");
 349                                 }
 350                                 th->addr = tha;
 351                                 if (rev)
 352                                         th->ack = seq, th->seq = ack - 1;
 353                                 else
 354                                         th->seq = seq, th->ack = ack - 1;
 355                         } else {
 356                                 if (rev)
 357                                         seq -= th->ack, ack -= th->seq;
 358                                 else
 359                                         seq -= th->seq, ack -= th->ack;
 360                         }
 361
 362                         thseq = th->seq;
 363                         thack = th->ack;
 364                 }
 365         } else {
 366                 /*fool gcc*/
 367                 thseq = thack = rev = 0;
 368         }
 369         if (hlen > length) {
 370                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 371                              hlen, length));
 372                 return;
 373         }
 374
 375         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 376                 /* Check the checksum, if possible. */
 377                 uint16_t sum, tcp_sum;
 378
 379                 if (IP_V(ip) == 4) {
 380                         if (ND_TTEST2(tp->th_sport, length)) {
 381                                 sum = tcp_cksum(ndo, ip, tp, length);
 382                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 383
 384                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 385                                 if (sum != 0)
 386                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 387                                             in_cksum_shouldbe(tcp_sum, sum)));
 388                                 else
 389                                         ND_PRINT((ndo, " (correct)"));
 390                         }
 391                 }
 392 #ifdef INET6
 393                 else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 394                         if (ND_TTEST2(tp->th_sport, length)) {
 395                                 sum = nextproto6_cksum(ip6, (const uint8_t *)tp,
 396                                                         length, length, IPPROTO_TCP);
 397                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 398
 399                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 400                                 if (sum != 0)
 401                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 402                                             in_cksum_shouldbe(tcp_sum, sum)));
 403                                 else
 404                                         ND_PRINT((ndo, " (correct)"));
 405
 406                         }
 407                 }
 408 #endif
 409         }
 410
 411         length -= hlen;
 412         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 413                 ND_PRINT((ndo, ", seq %u", seq));
 414
 415                 if (length > 0) {
 416                         ND_PRINT((ndo, ":%u", seq + length));
 417                 }
 418         }
 419
 420         if (flags & TH_ACK) {
 421                 ND_PRINT((ndo, ", ack %u", ack));
 422         }
 423
 424         ND_PRINT((ndo, ", win %d", win));
 425
 426         if (flags & TH_URG)
 427                 ND_PRINT((ndo, ", urg %d", urp));
 428         /*
 429          * Handle any options.
 430          */
 431         if (hlen > sizeof(*tp)) {
 432                 register const u_char *cp;
 433                 register u_int i, opt, datalen;
 434                 register u_int len;
 435
 436                 hlen -= sizeof(*tp);
 437                 cp = (const u_char *)tp + sizeof(*tp);
 438                 ND_PRINT((ndo, ", options ["));
 439                 while (hlen > 0) {
 440                         if (ch != '\0')
 441                                 ND_PRINT((ndo, "%c", ch));
 442                         ND_TCHECK(*cp);
 443                         opt = *cp++;
 444                         if (ZEROLENOPT(opt))
 445                                 len = 1;
 446                         else {
 447                                 ND_TCHECK(*cp);
 448                                 len = *cp++;    /* total including type, len */
 449                                 if (len < 2 || len > hlen)
 450                                         goto bad;
 451                                 --hlen;         /* account for length byte */
 452                         }
 453                         --hlen;                 /* account for type byte */
 454                         datalen = 0;
 455
 456 /* Bail if "l" bytes of data are not left or were not captured  */
 457 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 458
 459
 460                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 461
 462                         switch (opt) {
 463
 464                         case TCPOPT_MAXSEG:
 465                                 datalen = 2;
 466                                 LENCHECK(datalen);
 467                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 468                                 break;
 469
 470                         case TCPOPT_WSCALE:
 471                                 datalen = 1;
 472                                 LENCHECK(datalen);
 473                                 ND_PRINT((ndo, " %u", *cp));
 474                                 break;
 475
 476                         case TCPOPT_SACK:
 477                                 datalen = len - 2;
 478                                 if (datalen % 8 != 0) {
 479                                         ND_PRINT((ndo, "invalid sack"));
 480                                 } else {
 481                                         uint32_t s, e;
 482
 483                                         ND_PRINT((ndo, " %d ", datalen / 8));
 484                                         for (i = 0; i < datalen; i += 8) {
 485                                                 LENCHECK(i + 4);
 486                                                 s = EXTRACT_32BITS(cp + i);
 487                                                 LENCHECK(i + 8);
 488                                                 e = EXTRACT_32BITS(cp + i + 4);
 489                                                 if (rev) {
 490                                                         s -= thseq;
 491                                                         e -= thseq;
 492                                                 } else {
 493                                                         s -= thack;
 494                                                         e -= thack;
 495                                                 }
 496                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 497                                         }
 498                                 }
 499                                 break;
 500
 501                         case TCPOPT_CC:
 502                         case TCPOPT_CCNEW:
 503                         case TCPOPT_CCECHO:
 504                         case TCPOPT_ECHO:
 505                         case TCPOPT_ECHOREPLY:
 506
 507                                 /*
 508                                  * those options share their semantics.
 509                                  * fall through
 510                                  */
 511                                 datalen = 4;
 512                                 LENCHECK(datalen);
 513                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 514                                 break;
 515
 516                         case TCPOPT_TIMESTAMP:
 517                                 datalen = 8;
 518                                 LENCHECK(datalen);
 519                                 ND_PRINT((ndo, " val %u ecr %u",
 520                                              EXTRACT_32BITS(cp),
 521                                              EXTRACT_32BITS(cp + 4)));
 522                                 break;
 523
 524                         case TCPOPT_SIGNATURE:
 525                                 datalen = TCP_SIGLEN;
 526                                 LENCHECK(datalen);
 527 #ifdef HAVE_LIBCRYPTO
 528                                 switch (tcp_verify_signature(ndo, ip, tp,
 529                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 530
 531                                 case SIGNATURE_VALID:
 532                                         ND_PRINT((ndo, "valid"));
 533                                         break;
 534
 535                                 case SIGNATURE_INVALID:
 536                                         ND_PRINT((ndo, "invalid"));
 537                                         break;
 538
 539                                 case CANT_CHECK_SIGNATURE:
 540                                         ND_PRINT((ndo, "can't check - "));
 541                                         for (i = 0; i < TCP_SIGLEN; ++i)
 542                                                 ND_PRINT((ndo, "%02x", cp[i]));
 543                                         break;
 544                                 }
 545 #else
 546                                 for (i = 0; i < TCP_SIGLEN; ++i)
 547                                         ND_PRINT((ndo, "%02x", cp[i]));
 548 #endif
 549                                 break;
 550
 551                         case TCPOPT_AUTH:
 552                                 ND_PRINT((ndo, "keyid %d", *cp++));
 553                                 datalen = len - 3;
 554                                 for (i = 0; i < datalen; ++i) {
 555                                         LENCHECK(i);
 556                                         ND_PRINT((ndo, "%02x", cp[i]));
 557                                 }
 558                                 break;
 559
 560
 561                         case TCPOPT_EOL:
 562                         case TCPOPT_NOP:
 563                         case TCPOPT_SACKOK:
 564                                 /*
 565                                  * Nothing interesting.
 566                                  * fall through
 567                                  */
 568                                 break;
 569
 570                         case TCPOPT_UTO:
 571                                 datalen = 2;
 572                                 LENCHECK(datalen);
 573                                 utoval = EXTRACT_16BITS(cp);
 574                                 ND_PRINT((ndo, "0x%x", utoval));
 575                                 if (utoval & 0x0001)
 576                                         utoval = (utoval >> 1) * 60;
 577                                 else
 578                                         utoval >>= 1;
 579                                 ND_PRINT((ndo, " %u", utoval));
 580                                 break;
 581
 582                         case TCPOPT_MPTCP:
 583                                 datalen = len - 2;
 584                                 LENCHECK(datalen);
 585                                 if (!mptcp_print(ndo, cp-2, len, flags))
 586                                         goto bad;
 587                                 break;
 588
 589                         case TCPOPT_FASTOPEN:
 590                                 datalen = len - 2;
 591                                 LENCHECK(datalen);
 592                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 593                                 break;
 594
 595                         case TCPOPT_EXPERIMENT2:
 596                                 datalen = len - 2;
 597                                 LENCHECK(datalen);
 598                                 if (datalen < 2)
 599                                         goto bad;
 600                                 /* RFC6994 */
 601                                 magic = EXTRACT_16BITS(cp);
 602                                 ND_PRINT((ndo, "-"));
 603
 604                                 switch(magic) {
 605
 606                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 607                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 608                                         break;
 609
 610                                 default:
 611                                         /* Unknown magic number */
 612                                         ND_PRINT((ndo, "%04x", magic));
 613                                         break;
 614                                 }
 615                                 break;
 616
 617                         default:
 618                                 datalen = len - 2;
 619                                 if (datalen)
 620                                         ND_PRINT((ndo, " 0x"));
 621                                 for (i = 0; i < datalen; ++i) {
 622                                         LENCHECK(i);
 623                                         ND_PRINT((ndo, "%02x", cp[i]));
 624                                 }
 625                                 break;
 626                         }
 627
 628                         /* Account for data printed */
 629                         cp += datalen;
 630                         hlen -= datalen;
 631
 632                         /* Check specification against observed length */
 633                         ++datalen;                      /* option octet */
 634                         if (!ZEROLENOPT(opt))
 635                                 ++datalen;              /* size octet */
 636                         if (datalen != len)
 637                                 ND_PRINT((ndo, "[len %d]", len));
 638                         ch = ',';
 639                         if (opt == TCPOPT_EOL)
 640                                 break;
 641                 }
 642                 ND_PRINT((ndo, "]"));
 643         }
 644
 645         /*
 646          * Print length field before crawling down the stack.
 647          */
 648         ND_PRINT((ndo, ", length %u", length));
 649
 650         if (length <= 0)
 651                 return;
 652
 653         /*
 654          * Decode payload if necessary.
 655          */
 656         bp += TH_OFF(tp) * 4;
 657         if ((flags & TH_RST) && ndo->ndo_vflag) {
 658                 print_tcp_rst_data(ndo, bp, length);
 659                 return;
 660         }
 661
 662         if (ndo->ndo_packettype) {
 663                 switch (ndo->ndo_packettype) {
 664                 case PT_ZMTP1:
 665                         zmtp1_print(ndo, bp, length);
 666                         break;
 667                 }
 668                 return;
 669         }
 670
 671         if (sport == TELNET_PORT || dport == TELNET_PORT) {
 672                 telnet_print(ndo, bp, length);
 673         } else if (sport == SMTP_PORT || dport == SMTP_PORT) {
 674                 ND_PRINT((ndo, ": "));
 675                 smtp_print(ndo, bp, length);
 676         } else if (sport == BGP_PORT || dport == BGP_PORT)
 677                 bgp_print(ndo, bp, length);
 678         else if (sport == PPTP_PORT || dport == PPTP_PORT)
 679                 pptp_print(ndo, bp);
 680 #ifdef TCPDUMP_DO_SMB
 681         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 682                 nbt_tcp_print(ndo, bp, length);
 683         else if (sport == SMB_PORT || dport == SMB_PORT)
 684                 smb_tcp_print(ndo, bp, length);
 685 #endif
 686         else if (sport == BEEP_PORT || dport == BEEP_PORT)
 687                 beep_print(ndo, bp, length);
 688         else if (sport == OPENFLOW_PORT_OLD || dport == OPENFLOW_PORT_OLD ||
 689                  sport == OPENFLOW_PORT_IANA || dport == OPENFLOW_PORT_IANA)
 690                 openflow_print(ndo, bp, length);
 691         else if (sport == FTP_PORT || dport == FTP_PORT) {
 692                 ND_PRINT((ndo, ": "));
 693                 ftp_print(ndo, bp, length);
 694         } else if (sport == HTTP_PORT || dport == HTTP_PORT ||
 695             sport == HTTP_PORT_ALT || dport == HTTP_PORT_ALT) {
 696                 ND_PRINT((ndo, ": "));
 697                 http_print(ndo, bp, length);
 698         } else if (sport == RTSP_PORT || dport == RTSP_PORT ||
 699             sport == RTSP_PORT_ALT || dport == RTSP_PORT_ALT) {
 700                 ND_PRINT((ndo, ": "));
 701                 rtsp_print(ndo, bp, length);
 702         } else if (length > 2 &&
 703                  (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT)) {
 704                 /*
 705                  * TCP DNS query has 2byte length at the head.
 706                  * XXX packet could be unaligned, it can go strange
 707                  */
 708                 ns_print(ndo, bp + 2, length - 2, 0);
 709         } else if (sport == MSDP_PORT || dport == MSDP_PORT) {
 710                 msdp_print(ndo, bp, length);
 711         } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) {
 712                 rpki_rtr_print(ndo, bp, length);
 713         }
 714         else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) {
 715                 ldp_print(ndo, bp, length);
 716         }
 717         else if ((sport == NFS_PORT || dport == NFS_PORT) &&
 718                  length >= 4 && ND_TTEST2(*bp, 4)) {
 719                 /*
 720                  * If data present, header length valid, and NFS port used,
 721                  * assume NFS.
 722                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 723                  * to NFS print routines.
 724                  */
 725                 uint32_t fraglen;
 726                 register const struct sunrpc_msg *rp;
 727                 enum sunrpc_msg_type direction;
 728
 729                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 730                 if (fraglen > (length) - 4)
 731                         fraglen = (length) - 4;
 732                 rp = (const struct sunrpc_msg *)(bp + 4);
 733                 if (ND_TTEST(rp->rm_direction)) {
 734                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 735                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 736                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 737                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 738                                 return;
 739                         }
 740                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 741                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 742                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 743                                 return;
 744                         }
 745                 }
 746         }
 747
 748         return;
 749  bad:
 750         ND_PRINT((ndo, "[bad opt]"));
 751         if (ch != '\0')
 752                 ND_PRINT((ndo, ">"));
 753         return;
 754  trunc:
 755         ND_PRINT((ndo, "[|tcp]"));
 756         if (ch != '\0')
 757                 ND_PRINT((ndo, ">"));
 758 }
 759
 760 /*
 761  * RFC1122 says the following on data in RST segments:
 762  *
 763  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 764  *
 765  *            A TCP SHOULD allow a received RST segment to include data.
 766  *
 767  *            DISCUSSION
 768  *                 It has been suggested that a RST segment could contain
 769  *                 ASCII text that encoded and explained the cause of the
 770  *                 RST.  No standard has yet been established for such
 771  *                 data.
 772  *
 773  */
 774
 775 static void
 776 print_tcp_rst_data(netdissect_options *ndo,
 777                    register const u_char *sp, u_int length)
 778 {
 779         int c;
 780
 781         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 782         if (length > MAX_RST_DATA_LEN) {
 783                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 784                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 785         }
 786         ND_PRINT((ndo, " "));
 787         while (length-- && sp <= ndo->ndo_snapend) {
 788                 c = *sp++;
 789                 safeputchar(ndo, c);
 790         }
 791         ND_PRINT((ndo, "]"));
 792 }
 793
 794 static void
 795 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 796                           u_int datalen, int exp)
 797 {
 798         u_int i;
 799
 800         if (exp)
 801                 ND_PRINT((ndo, "tfo"));
 802
 803         if (datalen == 0) {
 804                 /* Fast Open Cookie Request */
 805                 ND_PRINT((ndo, " cookiereq"));
 806         } else {
 807                 /* Fast Open Cookie */
 808                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 809                         ND_PRINT((ndo, " invalid"));
 810                 } else {
 811                         ND_PRINT((ndo, " cookie "));
 812                         for (i = 0; i < datalen; ++i)
 813                                 ND_PRINT((ndo, "%02x", cp[i]));
 814                 }
 815         }
 816 }
 817
 818 #ifdef HAVE_LIBCRYPTO
 819 USES_APPLE_DEPRECATED_API
 820 static int
 821 tcp_verify_signature(netdissect_options *ndo,
 822                      const struct ip *ip, const struct tcphdr *tp,
 823                      const u_char *data, int length, const u_char *rcvsig)
 824 {
 825         struct tcphdr tp1;
 826         u_char sig[TCP_SIGLEN];
 827         char zero_proto = 0;
 828         MD5_CTX ctx;
 829         uint16_t savecsum, tlen;
 830 #ifdef INET6
 831         const struct ip6_hdr *ip6;
 832         uint32_t len32;
 833         uint8_t nxt;
 834 #endif
 835
 836         if (data + length > ndo->ndo_snapend) {
 837                 ND_PRINT((ndo, "snaplen too short, "));
 838                 return (CANT_CHECK_SIGNATURE);
 839         }
 840
 841         tp1 = *tp;
 842
 843         if (ndo->ndo_sigsecret == NULL) {
 844                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 845                 return (CANT_CHECK_SIGNATURE);
 846         }
 847
 848         MD5_Init(&ctx);
 849         /*
 850          * Step 1: Update MD5 hash with IP pseudo-header.
 851          */
 852         if (IP_V(ip) == 4) {
 853                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 854                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 855                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 856                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 857                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 858                 tlen = htons(tlen);
 859                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 860 #ifdef INET6
 861         } else if (IP_V(ip) == 6) {
 862                 ip6 = (const struct ip6_hdr *)ip;
 863                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 864                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 865                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 866                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 867                 nxt = 0;
 868                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 869                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 870                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 871                 nxt = IPPROTO_TCP;
 872                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 873 #endif
 874         } else {
 875 #ifdef INET6
 876                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 877 #else
 878                 ND_PRINT((ndo, "IP version not 4, "));
 879 #endif
 880                 return (CANT_CHECK_SIGNATURE);
 881         }
 882
 883         /*
 884          * Step 2: Update MD5 hash with TCP header, excluding options.
 885          * The TCP checksum must be set to zero.
 886          */
 887         savecsum = tp1.th_sum;
 888         tp1.th_sum = 0;
 889         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 890         tp1.th_sum = savecsum;
 891         /*
 892          * Step 3: Update MD5 hash with TCP segment data, if present.
 893          */
 894         if (length > 0)
 895                 MD5_Update(&ctx, data, length);
 896         /*
 897          * Step 4: Update MD5 hash with shared secret.
 898          */
 899         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 900         MD5_Final(sig, &ctx);
 901
 902         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 903                 return (SIGNATURE_VALID);
 904         else
 905                 return (SIGNATURE_INVALID);
 906 }
 907 USES_APPLE_RST
 908 #endif /* HAVE_LIBCRYPTO */
 909
 910 /*
 911  * Local Variables:
 912  * c-style: whitesmith
 913  * c-basic-offset: 8
 914  * End:
 915  */