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, 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 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         tcp_seq seq;
  93         tcp_seq 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_AUTH, "enhanced auth" },
 131         { TCPOPT_UTO, "uto" },
 132         { TCPOPT_MPTCP, "mptcp" },
 133         { TCPOPT_FASTOPEN, "tfo" },
 134         { TCPOPT_EXPERIMENT2, "exp" },
 135         { 0, NULL }
 136 };
 137
 138 static int
 139 tcp_cksum(netdissect_options *ndo,
 140           register const struct ip *ip,
 141           register const struct tcphdr *tp,
 142           register u_int len)
 143 {
 144         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 145                                 IPPROTO_TCP);
 146 }
 147
 148 static int
 149 tcp6_cksum(netdissect_options *ndo,
 150            register const struct ip6_hdr *ip6,
 151            register const struct tcphdr *tp,
 152            register u_int len)
 153 {
 154         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 155                                 IPPROTO_TCP);
 156 }
 157
 158 void
 159 tcp_print(netdissect_options *ndo,
 160           register const u_char *bp, register u_int length,
 161           register const u_char *bp2, int fragmented)
 162 {
 163         register const struct tcphdr *tp;
 164         register const struct ip *ip;
 165         register u_char flags;
 166         register u_int hlen;
 167         register char ch;
 168         uint16_t sport, dport, win, urp;
 169         uint32_t seq, ack, thseq, thack;
 170         u_int utoval;
 171         uint16_t magic;
 172         register int rev;
 173         register const struct ip6_hdr *ip6;
 174
 175         tp = (const struct tcphdr *)bp;
 176         ip = (const struct ip *)bp2;
 177         if (IP_V(ip) == 6)
 178                 ip6 = (const struct ip6_hdr *)bp2;
 179         else
 180                 ip6 = NULL;
 181         ch = '\0';
 182         if (!ND_TTEST(tp->th_dport)) {
 183                 ND_PRINT((ndo, "%s > %s: [|tcp]",
 184                              ipaddr_string(ndo, &ip->ip_src),
 185                              ipaddr_string(ndo, &ip->ip_dst)));
 186                 return;
 187         }
 188
 189         sport = EXTRACT_16BITS(&tp->th_sport);
 190         dport = EXTRACT_16BITS(&tp->th_dport);
 191
 192         hlen = TH_OFF(tp) * 4;
 193
 194         if (ip6) {
 195                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 196                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 197                                      ip6addr_string(ndo, &ip6->ip6_src),
 198                                      tcpport_string(ndo, sport),
 199                                      ip6addr_string(ndo, &ip6->ip6_dst),
 200                                      tcpport_string(ndo, dport)));
 201                 } else {
 202                         ND_PRINT((ndo, "%s > %s: ",
 203                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 204                 }
 205         } else {
 206                 if (ip->ip_p == IPPROTO_TCP) {
 207                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 208                                      ipaddr_string(ndo, &ip->ip_src),
 209                                      tcpport_string(ndo, sport),
 210                                      ipaddr_string(ndo, &ip->ip_dst),
 211                                      tcpport_string(ndo, dport)));
 212                 } else {
 213                         ND_PRINT((ndo, "%s > %s: ",
 214                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 215                 }
 216         }
 217
 218         if (hlen < sizeof(*tp)) {
 219                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 220                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 221                 return;
 222         }
 223
 224         ND_TCHECK(*tp);
 225
 226         seq = EXTRACT_32BITS(&tp->th_seq);
 227         ack = EXTRACT_32BITS(&tp->th_ack);
 228         win = EXTRACT_16BITS(&tp->th_win);
 229         urp = EXTRACT_16BITS(&tp->th_urp);
 230
 231         if (ndo->ndo_qflag) {
 232                 ND_PRINT((ndo, "tcp %d", length - hlen));
 233                 if (hlen > length) {
 234                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 235                                      hlen, length));
 236                 }
 237                 return;
 238         }
 239
 240         flags = tp->th_flags;
 241         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
 242
 243         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 244                 /*
 245                  * Find (or record) the initial sequence numbers for
 246                  * this conversation.  (we pick an arbitrary
 247                  * collating order so there's only one entry for
 248                  * both directions).
 249                  */
 250                 rev = 0;
 251                 if (ip6) {
 252                         register struct tcp_seq_hash6 *th;
 253                         struct tcp_seq_hash6 *tcp_seq_hash;
 254                         const struct in6_addr *src, *dst;
 255                         struct tha6 tha;
 256
 257                         tcp_seq_hash = tcp_seq_hash6;
 258                         src = &ip6->ip6_src;
 259                         dst = &ip6->ip6_dst;
 260                         if (sport > dport)
 261                                 rev = 1;
 262                         else if (sport == dport) {
 263                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 264                                         rev = 1;
 265                         }
 266                         if (rev) {
 267                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 268                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 269                                 tha.port = dport << 16 | sport;
 270                         } else {
 271                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 272                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 273                                 tha.port = sport << 16 | dport;
 274                         }
 275
 276                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 277                              th->nxt; th = th->nxt)
 278                                 if (memcmp((char *)&tha, (char *)&th->addr,
 279                                            sizeof(th->addr)) == 0)
 280                                         break;
 281
 282                         if (!th->nxt || (flags & TH_SYN)) {
 283                                 /* didn't find it or new conversation */
 284                                 if (th->nxt == NULL) {
 285                                         th->nxt = (struct tcp_seq_hash6 *)
 286                                                 calloc(1, sizeof(*th));
 287                                         if (th->nxt == NULL)
 288                                                 (*ndo->ndo_error)(ndo,
 289                                                                   "tcp_print: calloc");
 290                                 }
 291                                 th->addr = tha;
 292                                 if (rev)
 293                                         th->ack = seq, th->seq = ack - 1;
 294                                 else
 295                                         th->seq = seq, th->ack = ack - 1;
 296                         } else {
 297                                 if (rev)
 298                                         seq -= th->ack, ack -= th->seq;
 299                                 else
 300                                         seq -= th->seq, ack -= th->ack;
 301                         }
 302
 303                         thseq = th->seq;
 304                         thack = th->ack;
 305                 } else {
 306                         register struct tcp_seq_hash *th;
 307                         struct tcp_seq_hash *tcp_seq_hash;
 308                         struct tha tha;
 309
 310                         tcp_seq_hash = tcp_seq_hash4;
 311                         if (sport > dport)
 312                                 rev = 1;
 313                         else if (sport == dport) {
 314                                 if (UNALIGNED_MEMCMP(&ip->ip_src, &ip->ip_dst, sizeof ip->ip_dst) > 0)
 315                                         rev = 1;
 316                         }
 317                         if (rev) {
 318                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_dst, sizeof ip->ip_dst);
 319                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_src, sizeof ip->ip_src);
 320                                 tha.port = dport << 16 | sport;
 321                         } else {
 322                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_dst, sizeof ip->ip_dst);
 323                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_src, sizeof ip->ip_src);
 324                                 tha.port = sport << 16 | dport;
 325                         }
 326
 327                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 328                              th->nxt; th = th->nxt)
 329                                 if (memcmp((char *)&tha, (char *)&th->addr,
 330                                            sizeof(th->addr)) == 0)
 331                                         break;
 332
 333                         if (!th->nxt || (flags & TH_SYN)) {
 334                                 /* didn't find it or new conversation */
 335                                 if (th->nxt == NULL) {
 336                                         th->nxt = (struct tcp_seq_hash *)
 337                                                 calloc(1, sizeof(*th));
 338                                         if (th->nxt == NULL)
 339                                                 (*ndo->ndo_error)(ndo,
 340                                                                   "tcp_print: calloc");
 341                                 }
 342                                 th->addr = tha;
 343                                 if (rev)
 344                                         th->ack = seq, th->seq = ack - 1;
 345                                 else
 346                                         th->seq = seq, th->ack = ack - 1;
 347                         } else {
 348                                 if (rev)
 349                                         seq -= th->ack, ack -= th->seq;
 350                                 else
 351                                         seq -= th->seq, ack -= th->ack;
 352                         }
 353
 354                         thseq = th->seq;
 355                         thack = th->ack;
 356                 }
 357         } else {
 358                 /*fool gcc*/
 359                 thseq = thack = rev = 0;
 360         }
 361         if (hlen > length) {
 362                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 363                              hlen, length));
 364                 return;
 365         }
 366
 367         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 368                 /* Check the checksum, if possible. */
 369                 uint16_t sum, tcp_sum;
 370
 371                 if (IP_V(ip) == 4) {
 372                         if (ND_TTEST2(tp->th_sport, length)) {
 373                                 sum = tcp_cksum(ndo, ip, tp, length);
 374                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 375
 376                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 377                                 if (sum != 0)
 378                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 379                                             in_cksum_shouldbe(tcp_sum, sum)));
 380                                 else
 381                                         ND_PRINT((ndo, " (correct)"));
 382                         }
 383                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 384                         if (ND_TTEST2(tp->th_sport, length)) {
 385                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 386                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 387
 388                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 389                                 if (sum != 0)
 390                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 391                                             in_cksum_shouldbe(tcp_sum, sum)));
 392                                 else
 393                                         ND_PRINT((ndo, " (correct)"));
 394
 395                         }
 396                 }
 397         }
 398
 399         length -= hlen;
 400         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 401                 ND_PRINT((ndo, ", seq %u", seq));
 402
 403                 if (length > 0) {
 404                         ND_PRINT((ndo, ":%u", seq + length));
 405                 }
 406         }
 407
 408         if (flags & TH_ACK) {
 409                 ND_PRINT((ndo, ", ack %u", ack));
 410         }
 411
 412         ND_PRINT((ndo, ", win %d", win));
 413
 414         if (flags & TH_URG)
 415                 ND_PRINT((ndo, ", urg %d", urp));
 416         /*
 417          * Handle any options.
 418          */
 419         if (hlen > sizeof(*tp)) {
 420                 register const u_char *cp;
 421                 register u_int i, opt, datalen;
 422                 register u_int len;
 423
 424                 hlen -= sizeof(*tp);
 425                 cp = (const u_char *)tp + sizeof(*tp);
 426                 ND_PRINT((ndo, ", options ["));
 427                 while (hlen > 0) {
 428                         if (ch != '\0')
 429                                 ND_PRINT((ndo, "%c", ch));
 430                         ND_TCHECK(*cp);
 431                         opt = *cp++;
 432                         if (ZEROLENOPT(opt))
 433                                 len = 1;
 434                         else {
 435                                 ND_TCHECK(*cp);
 436                                 len = *cp++;    /* total including type, len */
 437                                 if (len < 2 || len > hlen)
 438                                         goto bad;
 439                                 --hlen;         /* account for length byte */
 440                         }
 441                         --hlen;                 /* account for type byte */
 442                         datalen = 0;
 443
 444 /* Bail if "l" bytes of data are not left or were not captured  */
 445 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 446
 447
 448                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 449
 450                         switch (opt) {
 451
 452                         case TCPOPT_MAXSEG:
 453                                 datalen = 2;
 454                                 LENCHECK(datalen);
 455                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 456                                 break;
 457
 458                         case TCPOPT_WSCALE:
 459                                 datalen = 1;
 460                                 LENCHECK(datalen);
 461                                 ND_PRINT((ndo, " %u", *cp));
 462                                 break;
 463
 464                         case TCPOPT_SACK:
 465                                 datalen = len - 2;
 466                                 if (datalen % 8 != 0) {
 467                                         ND_PRINT((ndo, " invalid sack"));
 468                                 } else {
 469                                         uint32_t s, e;
 470
 471                                         ND_PRINT((ndo, " %d ", datalen / 8));
 472                                         for (i = 0; i < datalen; i += 8) {
 473                                                 LENCHECK(i + 4);
 474                                                 s = EXTRACT_32BITS(cp + i);
 475                                                 LENCHECK(i + 8);
 476                                                 e = EXTRACT_32BITS(cp + i + 4);
 477                                                 if (rev) {
 478                                                         s -= thseq;
 479                                                         e -= thseq;
 480                                                 } else {
 481                                                         s -= thack;
 482                                                         e -= thack;
 483                                                 }
 484                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 485                                         }
 486                                 }
 487                                 break;
 488
 489                         case TCPOPT_CC:
 490                         case TCPOPT_CCNEW:
 491                         case TCPOPT_CCECHO:
 492                         case TCPOPT_ECHO:
 493                         case TCPOPT_ECHOREPLY:
 494
 495                                 /*
 496                                  * those options share their semantics.
 497                                  * fall through
 498                                  */
 499                                 datalen = 4;
 500                                 LENCHECK(datalen);
 501                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 502                                 break;
 503
 504                         case TCPOPT_TIMESTAMP:
 505                                 datalen = 8;
 506                                 LENCHECK(datalen);
 507                                 ND_PRINT((ndo, " val %u ecr %u",
 508                                              EXTRACT_32BITS(cp),
 509                                              EXTRACT_32BITS(cp + 4)));
 510                                 break;
 511
 512                         case TCPOPT_SIGNATURE:
 513                                 datalen = TCP_SIGLEN;
 514                                 LENCHECK(datalen);
 515                                 ND_PRINT((ndo, " "));
 516 #ifdef HAVE_LIBCRYPTO
 517                                 switch (tcp_verify_signature(ndo, ip, tp,
 518                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 519
 520                                 case SIGNATURE_VALID:
 521                                         ND_PRINT((ndo, "valid"));
 522                                         break;
 523
 524                                 case SIGNATURE_INVALID:
 525                                         ND_PRINT((ndo, "invalid"));
 526                                         break;
 527
 528                                 case CANT_CHECK_SIGNATURE:
 529                                         ND_PRINT((ndo, "can't check - "));
 530                                         for (i = 0; i < TCP_SIGLEN; ++i)
 531                                                 ND_PRINT((ndo, "%02x", cp[i]));
 532                                         break;
 533                                 }
 534 #else
 535                                 for (i = 0; i < TCP_SIGLEN; ++i)
 536                                         ND_PRINT((ndo, "%02x", cp[i]));
 537 #endif
 538                                 break;
 539
 540                         case TCPOPT_AUTH:
 541                                 ND_PRINT((ndo, " keyid %d", *cp++));
 542                                 datalen = len - 3;
 543                                 for (i = 0; i < datalen; ++i) {
 544                                         LENCHECK(i + 1);
 545                                         ND_PRINT((ndo, "%02x", cp[i]));
 546                                 }
 547                                 break;
 548
 549
 550                         case TCPOPT_EOL:
 551                         case TCPOPT_NOP:
 552                         case TCPOPT_SACKOK:
 553                                 /*
 554                                  * Nothing interesting.
 555                                  * fall through
 556                                  */
 557                                 break;
 558
 559                         case TCPOPT_UTO:
 560                                 datalen = 2;
 561                                 LENCHECK(datalen);
 562                                 utoval = EXTRACT_16BITS(cp);
 563                                 ND_PRINT((ndo, " 0x%x", utoval));
 564                                 if (utoval & 0x0001)
 565                                         utoval = (utoval >> 1) * 60;
 566                                 else
 567                                         utoval >>= 1;
 568                                 ND_PRINT((ndo, " %u", utoval));
 569                                 break;
 570
 571                         case TCPOPT_MPTCP:
 572                                 datalen = len - 2;
 573                                 LENCHECK(datalen);
 574                                 if (!mptcp_print(ndo, cp-2, len, flags))
 575                                         goto bad;
 576                                 break;
 577
 578                         case TCPOPT_FASTOPEN:
 579                                 datalen = len - 2;
 580                                 LENCHECK(datalen);
 581                                 ND_PRINT((ndo, " "));
 582                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 583                                 break;
 584
 585                         case TCPOPT_EXPERIMENT2:
 586                                 datalen = len - 2;
 587                                 LENCHECK(datalen);
 588                                 if (datalen < 2)
 589                                         goto bad;
 590                                 /* RFC6994 */
 591                                 magic = EXTRACT_16BITS(cp);
 592                                 ND_PRINT((ndo, "-"));
 593
 594                                 switch(magic) {
 595
 596                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 597                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 598                                         break;
 599
 600                                 default:
 601                                         /* Unknown magic number */
 602                                         ND_PRINT((ndo, "%04x", magic));
 603                                         break;
 604                                 }
 605                                 break;
 606
 607                         default:
 608                                 datalen = len - 2;
 609                                 if (datalen)
 610                                         ND_PRINT((ndo, " 0x"));
 611                                 for (i = 0; i < datalen; ++i) {
 612                                         LENCHECK(i + 1);
 613                                         ND_PRINT((ndo, "%02x", cp[i]));
 614                                 }
 615                                 break;
 616                         }
 617
 618                         /* Account for data printed */
 619                         cp += datalen;
 620                         hlen -= datalen;
 621
 622                         /* Check specification against observed length */
 623                         ++datalen;                      /* option octet */
 624                         if (!ZEROLENOPT(opt))
 625                                 ++datalen;              /* size octet */
 626                         if (datalen != len)
 627                                 ND_PRINT((ndo, "[len %d]", len));
 628                         ch = ',';
 629                         if (opt == TCPOPT_EOL)
 630                                 break;
 631                 }
 632                 ND_PRINT((ndo, "]"));
 633         }
 634
 635         /*
 636          * Print length field before crawling down the stack.
 637          */
 638         ND_PRINT((ndo, ", length %u", length));
 639
 640         if (length <= 0)
 641                 return;
 642
 643         /*
 644          * Decode payload if necessary.
 645          */
 646         bp += TH_OFF(tp) * 4;
 647         if ((flags & TH_RST) && ndo->ndo_vflag) {
 648                 print_tcp_rst_data(ndo, bp, length);
 649                 return;
 650         }
 651
 652         if (ndo->ndo_packettype) {
 653                 switch (ndo->ndo_packettype) {
 654                 case PT_ZMTP1:
 655                         zmtp1_print(ndo, bp, length);
 656                         break;
 657                 case PT_RESP:
 658                         resp_print(ndo, bp, length);
 659                         break;
 660                 }
 661                 return;
 662         }
 663
 664         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 665                 telnet_print(ndo, bp, length);
 666         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 667                 ND_PRINT((ndo, ": "));
 668                 smtp_print(ndo, bp, length);
 669         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 670                 bgp_print(ndo, bp, length);
 671         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 672                 pptp_print(ndo, bp);
 673         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 674                 resp_print(ndo, bp, length);
 675 #ifdef ENABLE_SMB
 676         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 677                 nbt_tcp_print(ndo, bp, length);
 678         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 679                 smb_tcp_print(ndo, bp, length);
 680 #endif
 681         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 682                 beep_print(ndo, bp, length);
 683         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 684                 openflow_print(ndo, bp, length);
 685         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 686                 ND_PRINT((ndo, ": "));
 687                 ftp_print(ndo, bp, length);
 688         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 689                 ND_PRINT((ndo, ": "));
 690                 http_print(ndo, bp, length);
 691         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 692                 ND_PRINT((ndo, ": "));
 693                 rtsp_print(ndo, bp, length);
 694         } else if (length > 2 &&
 695                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 696                 /*
 697                  * TCP DNS query has 2byte length at the head.
 698                  * XXX packet could be unaligned, it can go strange
 699                  */
 700                 ns_print(ndo, bp + 2, length - 2, 0);
 701         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 702                 msdp_print(ndo, bp, length);
 703         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 704                 rpki_rtr_print(ndo, bp, length);
 705         }
 706         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 707                 ldp_print(ndo, bp, length);
 708         }
 709         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 710                  length >= 4 && ND_TTEST2(*bp, 4)) {
 711                 /*
 712                  * If data present, header length valid, and NFS port used,
 713                  * assume NFS.
 714                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 715                  * to NFS print routines.
 716                  */
 717                 uint32_t fraglen;
 718                 register const struct sunrpc_msg *rp;
 719                 enum sunrpc_msg_type direction;
 720
 721                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 722                 if (fraglen > (length) - 4)
 723                         fraglen = (length) - 4;
 724                 rp = (const struct sunrpc_msg *)(bp + 4);
 725                 if (ND_TTEST(rp->rm_direction)) {
 726                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 727                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 728                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 729                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 730                                 return;
 731                         }
 732                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 733                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 734                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 735                                 return;
 736                         }
 737                 }
 738         }
 739
 740         return;
 741  bad:
 742         ND_PRINT((ndo, "[bad opt]"));
 743         if (ch != '\0')
 744                 ND_PRINT((ndo, ">"));
 745         return;
 746  trunc:
 747         ND_PRINT((ndo, "[|tcp]"));
 748         if (ch != '\0')
 749                 ND_PRINT((ndo, ">"));
 750 }
 751
 752 /*
 753  * RFC1122 says the following on data in RST segments:
 754  *
 755  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 756  *
 757  *            A TCP SHOULD allow a received RST segment to include data.
 758  *
 759  *            DISCUSSION
 760  *                 It has been suggested that a RST segment could contain
 761  *                 ASCII text that encoded and explained the cause of the
 762  *                 RST.  No standard has yet been established for such
 763  *                 data.
 764  *
 765  */
 766
 767 static void
 768 print_tcp_rst_data(netdissect_options *ndo,
 769                    register const u_char *sp, u_int length)
 770 {
 771         int c;
 772
 773         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 774         if (length > MAX_RST_DATA_LEN) {
 775                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 776                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 777         }
 778         ND_PRINT((ndo, " "));
 779         while (length-- && sp < ndo->ndo_snapend) {
 780                 c = *sp++;
 781                 safeputchar(ndo, c);
 782         }
 783         ND_PRINT((ndo, "]"));
 784 }
 785
 786 static void
 787 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 788                           u_int datalen, int exp)
 789 {
 790         u_int i;
 791
 792         if (exp)
 793                 ND_PRINT((ndo, "tfo"));
 794
 795         if (datalen == 0) {
 796                 /* Fast Open Cookie Request */
 797                 ND_PRINT((ndo, " cookiereq"));
 798         } else {
 799                 /* Fast Open Cookie */
 800                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 801                         ND_PRINT((ndo, " invalid"));
 802                 } else {
 803                         ND_PRINT((ndo, " cookie "));
 804                         for (i = 0; i < datalen; ++i)
 805                                 ND_PRINT((ndo, "%02x", cp[i]));
 806                 }
 807         }
 808 }
 809
 810 #ifdef HAVE_LIBCRYPTO
 811 USES_APPLE_DEPRECATED_API
 812 static int
 813 tcp_verify_signature(netdissect_options *ndo,
 814                      const struct ip *ip, const struct tcphdr *tp,
 815                      const u_char *data, int length, const u_char *rcvsig)
 816 {
 817         struct tcphdr tp1;
 818         u_char sig[TCP_SIGLEN];
 819         char zero_proto = 0;
 820         MD5_CTX ctx;
 821         uint16_t savecsum, tlen;
 822         const struct ip6_hdr *ip6;
 823         uint32_t len32;
 824         uint8_t nxt;
 825
 826         if (data + length > ndo->ndo_snapend) {
 827                 ND_PRINT((ndo, "snaplen too short, "));
 828                 return (CANT_CHECK_SIGNATURE);
 829         }
 830
 831         tp1 = *tp;
 832
 833         if (ndo->ndo_sigsecret == NULL) {
 834                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 835                 return (CANT_CHECK_SIGNATURE);
 836         }
 837
 838         MD5_Init(&ctx);
 839         /*
 840          * Step 1: Update MD5 hash with IP pseudo-header.
 841          */
 842         if (IP_V(ip) == 4) {
 843                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 844                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 845                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 846                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 847                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 848                 tlen = htons(tlen);
 849                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 850         } else if (IP_V(ip) == 6) {
 851                 ip6 = (const struct ip6_hdr *)ip;
 852                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 853                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 854                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 855                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 856                 nxt = 0;
 857                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 858                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 859                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 860                 nxt = IPPROTO_TCP;
 861                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 862         } else {
 863                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 864                 return (CANT_CHECK_SIGNATURE);
 865         }
 866
 867         /*
 868          * Step 2: Update MD5 hash with TCP header, excluding options.
 869          * The TCP checksum must be set to zero.
 870          */
 871         savecsum = tp1.th_sum;
 872         tp1.th_sum = 0;
 873         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 874         tp1.th_sum = savecsum;
 875         /*
 876          * Step 3: Update MD5 hash with TCP segment data, if present.
 877          */
 878         if (length > 0)
 879                 MD5_Update(&ctx, data, length);
 880         /*
 881          * Step 4: Update MD5 hash with shared secret.
 882          */
 883         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 884         MD5_Final(sig, &ctx);
 885
 886         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 887                 return (SIGNATURE_VALID);
 888         else
 889                 return (SIGNATURE_INVALID);
 890 }
 891 USES_APPLE_RST
 892 #endif /* HAVE_LIBCRYPTO */
 893
 894 /*
 895  * Local Variables:
 896  * c-style: whitesmith
 897  * c-basic-offset: 8
 898  * End:
 899  */