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 <netdissect-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 #include "ip6.h"
  48 #include "ipproto.h"
  49 #include "rpc_auth.h"
  50 #include "rpc_msg.h"
  51
  52 #ifdef HAVE_LIBCRYPTO
  53 #include <openssl/md5.h>
  54 #include "signature.h"
  55
  56 static int tcp_verify_signature(netdissect_options *ndo,
  57                                 const struct ip *ip, const struct tcphdr *tp,
  58                                 const u_char *data, int length, const u_char *rcvsig);
  59 #endif
  60
  61 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
  62 static void print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
  63                                       u_int datalen, int exp);
  64
  65 #define MAX_RST_DATA_LEN        30
  66
  67
  68 struct tha {
  69         struct in_addr src;
  70         struct in_addr dst;
  71         u_int port;
  72 };
  73
  74 struct tcp_seq_hash {
  75         struct tcp_seq_hash *nxt;
  76         struct tha addr;
  77         tcp_seq seq;
  78         tcp_seq ack;
  79 };
  80
  81 struct tha6 {
  82         struct in6_addr src;
  83         struct in6_addr dst;
  84         u_int port;
  85 };
  86
  87 struct tcp_seq_hash6 {
  88         struct tcp_seq_hash6 *nxt;
  89         struct tha6 addr;
  90         tcp_seq seq;
  91         tcp_seq ack;
  92 };
  93
  94 #define TSEQ_HASHSIZE 919
  95
  96 /* These tcp optinos do not have the size octet */
  97 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
  98
  99 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 100 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 101
 102 static const struct tok tcp_flag_values[] = {
 103         { TH_FIN, "F" },
 104         { TH_SYN, "S" },
 105         { TH_RST, "R" },
 106         { TH_PUSH, "P" },
 107         { TH_ACK, "." },
 108         { TH_URG, "U" },
 109         { TH_ECNECHO, "E" },
 110         { TH_CWR, "W" },
 111         { 0, NULL }
 112 };
 113
 114 static const struct tok tcp_option_values[] = {
 115         { TCPOPT_EOL, "eol" },
 116         { TCPOPT_NOP, "nop" },
 117         { TCPOPT_MAXSEG, "mss" },
 118         { TCPOPT_WSCALE, "wscale" },
 119         { TCPOPT_SACKOK, "sackOK" },
 120         { TCPOPT_SACK, "sack" },
 121         { TCPOPT_ECHO, "echo" },
 122         { TCPOPT_ECHOREPLY, "echoreply" },
 123         { TCPOPT_TIMESTAMP, "TS" },
 124         { TCPOPT_CC, "cc" },
 125         { TCPOPT_CCNEW, "ccnew" },
 126         { TCPOPT_CCECHO, "" },
 127         { TCPOPT_SIGNATURE, "md5" },
 128         { TCPOPT_AUTH, "enhanced auth" },
 129         { TCPOPT_UTO, "uto" },
 130         { TCPOPT_MPTCP, "mptcp" },
 131         { TCPOPT_FASTOPEN, "tfo" },
 132         { TCPOPT_EXPERIMENT2, "exp" },
 133         { 0, NULL }
 134 };
 135
 136 static int
 137 tcp_cksum(netdissect_options *ndo,
 138           register const struct ip *ip,
 139           register const struct tcphdr *tp,
 140           register u_int len)
 141 {
 142         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 143                                 IPPROTO_TCP);
 144 }
 145
 146 static int
 147 tcp6_cksum(netdissect_options *ndo,
 148            register const struct ip6_hdr *ip6,
 149            register const struct tcphdr *tp,
 150            register u_int len)
 151 {
 152         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 153                                 IPPROTO_TCP);
 154 }
 155
 156 void
 157 tcp_print(netdissect_options *ndo,
 158           register const u_char *bp, register u_int length,
 159           register const u_char *bp2, int fragmented)
 160 {
 161         register const struct tcphdr *tp;
 162         register const struct ip *ip;
 163         register u_char flags;
 164         register u_int hlen;
 165         register char ch;
 166         uint16_t sport, dport, win, urp;
 167         uint32_t seq, ack, thseq, thack;
 168         u_int utoval;
 169         uint16_t magic;
 170         register int rev;
 171         register const struct ip6_hdr *ip6;
 172
 173         tp = (const struct tcphdr *)bp;
 174         ip = (const struct ip *)bp2;
 175         if (IP_V(ip) == 6)
 176                 ip6 = (const struct ip6_hdr *)bp2;
 177         else
 178                 ip6 = NULL;
 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         if (ip6) {
 193                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 194                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 195                                      ip6addr_string(ndo, &ip6->ip6_src),
 196                                      tcpport_string(ndo, sport),
 197                                      ip6addr_string(ndo, &ip6->ip6_dst),
 198                                      tcpport_string(ndo, dport)));
 199                 } else {
 200                         ND_PRINT((ndo, "%s > %s: ",
 201                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 202                 }
 203         } else {
 204                 if (ip->ip_p == IPPROTO_TCP) {
 205                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 206                                      ipaddr_string(ndo, &ip->ip_src),
 207                                      tcpport_string(ndo, sport),
 208                                      ipaddr_string(ndo, &ip->ip_dst),
 209                                      tcpport_string(ndo, dport)));
 210                 } else {
 211                         ND_PRINT((ndo, "%s > %s: ",
 212                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 213                 }
 214         }
 215
 216         if (hlen < sizeof(*tp)) {
 217                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 218                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 219                 return;
 220         }
 221
 222         ND_TCHECK(*tp);
 223
 224         seq = EXTRACT_32BITS(&tp->th_seq);
 225         ack = EXTRACT_32BITS(&tp->th_ack);
 226         win = EXTRACT_16BITS(&tp->th_win);
 227         urp = EXTRACT_16BITS(&tp->th_urp);
 228
 229         if (ndo->ndo_qflag) {
 230                 ND_PRINT((ndo, "tcp %d", length - hlen));
 231                 if (hlen > length) {
 232                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 233                                      hlen, length));
 234                 }
 235                 return;
 236         }
 237
 238         flags = tp->th_flags;
 239         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
 240
 241         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 242                 /*
 243                  * Find (or record) the initial sequence numbers for
 244                  * this conversation.  (we pick an arbitrary
 245                  * collating order so there's only one entry for
 246                  * both directions).
 247                  */
 248                 rev = 0;
 249                 if (ip6) {
 250                         register struct tcp_seq_hash6 *th;
 251                         struct tcp_seq_hash6 *tcp_seq_hash;
 252                         const struct in6_addr *src, *dst;
 253                         struct tha6 tha;
 254
 255                         tcp_seq_hash = tcp_seq_hash6;
 256                         src = &ip6->ip6_src;
 257                         dst = &ip6->ip6_dst;
 258                         if (sport > dport)
 259                                 rev = 1;
 260                         else if (sport == dport) {
 261                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 262                                         rev = 1;
 263                         }
 264                         if (rev) {
 265                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 266                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 267                                 tha.port = dport << 16 | sport;
 268                         } else {
 269                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 270                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 271                                 tha.port = sport << 16 | dport;
 272                         }
 273
 274                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 275                              th->nxt; th = th->nxt)
 276                                 if (memcmp((char *)&tha, (char *)&th->addr,
 277                                            sizeof(th->addr)) == 0)
 278                                         break;
 279
 280                         if (!th->nxt || (flags & TH_SYN)) {
 281                                 /* didn't find it or new conversation */
 282                                 if (th->nxt == NULL) {
 283                                         th->nxt = (struct tcp_seq_hash6 *)
 284                                                 calloc(1, sizeof(*th));
 285                                         if (th->nxt == NULL)
 286                                                 (*ndo->ndo_error)(ndo,
 287                                                                   "tcp_print: calloc");
 288                                 }
 289                                 th->addr = tha;
 290                                 if (rev)
 291                                         th->ack = seq, th->seq = ack - 1;
 292                                 else
 293                                         th->seq = seq, th->ack = ack - 1;
 294                         } else {
 295                                 if (rev)
 296                                         seq -= th->ack, ack -= th->seq;
 297                                 else
 298                                         seq -= th->seq, ack -= th->ack;
 299                         }
 300
 301                         thseq = th->seq;
 302                         thack = th->ack;
 303                 } else {
 304                         register struct tcp_seq_hash *th;
 305                         struct tcp_seq_hash *tcp_seq_hash;
 306                         struct tha tha;
 307
 308                         tcp_seq_hash = tcp_seq_hash4;
 309                         if (sport > dport)
 310                                 rev = 1;
 311                         else if (sport == dport) {
 312                                 if (UNALIGNED_MEMCMP(&ip->ip_src, &ip->ip_dst, sizeof ip->ip_dst) > 0)
 313                                         rev = 1;
 314                         }
 315                         if (rev) {
 316                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_dst, sizeof ip->ip_dst);
 317                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_src, sizeof ip->ip_src);
 318                                 tha.port = dport << 16 | sport;
 319                         } else {
 320                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_dst, sizeof ip->ip_dst);
 321                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_src, sizeof ip->ip_src);
 322                                 tha.port = sport << 16 | dport;
 323                         }
 324
 325                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 326                              th->nxt; th = th->nxt)
 327                                 if (memcmp((char *)&tha, (char *)&th->addr,
 328                                            sizeof(th->addr)) == 0)
 329                                         break;
 330
 331                         if (!th->nxt || (flags & TH_SYN)) {
 332                                 /* didn't find it or new conversation */
 333                                 if (th->nxt == NULL) {
 334                                         th->nxt = (struct tcp_seq_hash *)
 335                                                 calloc(1, sizeof(*th));
 336                                         if (th->nxt == NULL)
 337                                                 (*ndo->ndo_error)(ndo,
 338                                                                   "tcp_print: calloc");
 339                                 }
 340                                 th->addr = tha;
 341                                 if (rev)
 342                                         th->ack = seq, th->seq = ack - 1;
 343                                 else
 344                                         th->seq = seq, th->ack = ack - 1;
 345                         } else {
 346                                 if (rev)
 347                                         seq -= th->ack, ack -= th->seq;
 348                                 else
 349                                         seq -= th->seq, ack -= th->ack;
 350                         }
 351
 352                         thseq = th->seq;
 353                         thack = th->ack;
 354                 }
 355         } else {
 356                 /*fool gcc*/
 357                 thseq = thack = rev = 0;
 358         }
 359         if (hlen > length) {
 360                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 361                              hlen, length));
 362                 return;
 363         }
 364
 365         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 366                 /* Check the checksum, if possible. */
 367                 uint16_t sum, tcp_sum;
 368
 369                 if (IP_V(ip) == 4) {
 370                         if (ND_TTEST2(tp->th_sport, length)) {
 371                                 sum = tcp_cksum(ndo, ip, tp, length);
 372                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 373
 374                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 375                                 if (sum != 0)
 376                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 377                                             in_cksum_shouldbe(tcp_sum, sum)));
 378                                 else
 379                                         ND_PRINT((ndo, " (correct)"));
 380                         }
 381                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 382                         if (ND_TTEST2(tp->th_sport, length)) {
 383                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 384                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 385
 386                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 387                                 if (sum != 0)
 388                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 389                                             in_cksum_shouldbe(tcp_sum, sum)));
 390                                 else
 391                                         ND_PRINT((ndo, " (correct)"));
 392
 393                         }
 394                 }
 395         }
 396
 397         length -= hlen;
 398         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 399                 ND_PRINT((ndo, ", seq %u", seq));
 400
 401                 if (length > 0) {
 402                         ND_PRINT((ndo, ":%u", seq + length));
 403                 }
 404         }
 405
 406         if (flags & TH_ACK) {
 407                 ND_PRINT((ndo, ", ack %u", ack));
 408         }
 409
 410         ND_PRINT((ndo, ", win %d", win));
 411
 412         if (flags & TH_URG)
 413                 ND_PRINT((ndo, ", urg %d", urp));
 414         /*
 415          * Handle any options.
 416          */
 417         if (hlen > sizeof(*tp)) {
 418                 register const u_char *cp;
 419                 register u_int i, opt, datalen;
 420                 register u_int len;
 421
 422                 hlen -= sizeof(*tp);
 423                 cp = (const u_char *)tp + sizeof(*tp);
 424                 ND_PRINT((ndo, ", options ["));
 425                 while (hlen > 0) {
 426                         if (ch != '\0')
 427                                 ND_PRINT((ndo, "%c", ch));
 428                         ND_TCHECK(*cp);
 429                         opt = *cp++;
 430                         if (ZEROLENOPT(opt))
 431                                 len = 1;
 432                         else {
 433                                 ND_TCHECK(*cp);
 434                                 len = *cp++;    /* total including type, len */
 435                                 if (len < 2 || len > hlen)
 436                                         goto bad;
 437                                 --hlen;         /* account for length byte */
 438                         }
 439                         --hlen;                 /* account for type byte */
 440                         datalen = 0;
 441
 442 /* Bail if "l" bytes of data are not left or were not captured  */
 443 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 444
 445
 446                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 447
 448                         switch (opt) {
 449
 450                         case TCPOPT_MAXSEG:
 451                                 datalen = 2;
 452                                 LENCHECK(datalen);
 453                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 454                                 break;
 455
 456                         case TCPOPT_WSCALE:
 457                                 datalen = 1;
 458                                 LENCHECK(datalen);
 459                                 ND_PRINT((ndo, " %u", *cp));
 460                                 break;
 461
 462                         case TCPOPT_SACK:
 463                                 datalen = len - 2;
 464                                 if (datalen % 8 != 0) {
 465                                         ND_PRINT((ndo, "invalid sack"));
 466                                 } else {
 467                                         uint32_t s, e;
 468
 469                                         ND_PRINT((ndo, " %d ", datalen / 8));
 470                                         for (i = 0; i < datalen; i += 8) {
 471                                                 LENCHECK(i + 4);
 472                                                 s = EXTRACT_32BITS(cp + i);
 473                                                 LENCHECK(i + 8);
 474                                                 e = EXTRACT_32BITS(cp + i + 4);
 475                                                 if (rev) {
 476                                                         s -= thseq;
 477                                                         e -= thseq;
 478                                                 } else {
 479                                                         s -= thack;
 480                                                         e -= thack;
 481                                                 }
 482                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 483                                         }
 484                                 }
 485                                 break;
 486
 487                         case TCPOPT_CC:
 488                         case TCPOPT_CCNEW:
 489                         case TCPOPT_CCECHO:
 490                         case TCPOPT_ECHO:
 491                         case TCPOPT_ECHOREPLY:
 492
 493                                 /*
 494                                  * those options share their semantics.
 495                                  * fall through
 496                                  */
 497                                 datalen = 4;
 498                                 LENCHECK(datalen);
 499                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 500                                 break;
 501
 502                         case TCPOPT_TIMESTAMP:
 503                                 datalen = 8;
 504                                 LENCHECK(datalen);
 505                                 ND_PRINT((ndo, " val %u ecr %u",
 506                                              EXTRACT_32BITS(cp),
 507                                              EXTRACT_32BITS(cp + 4)));
 508                                 break;
 509
 510                         case TCPOPT_SIGNATURE:
 511                                 datalen = TCP_SIGLEN;
 512                                 LENCHECK(datalen);
 513 #ifdef HAVE_LIBCRYPTO
 514                                 switch (tcp_verify_signature(ndo, ip, tp,
 515                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 516
 517                                 case SIGNATURE_VALID:
 518                                         ND_PRINT((ndo, "valid"));
 519                                         break;
 520
 521                                 case SIGNATURE_INVALID:
 522                                         ND_PRINT((ndo, "invalid"));
 523                                         break;
 524
 525                                 case CANT_CHECK_SIGNATURE:
 526                                         ND_PRINT((ndo, "can't check - "));
 527                                         for (i = 0; i < TCP_SIGLEN; ++i)
 528                                                 ND_PRINT((ndo, "%02x", cp[i]));
 529                                         break;
 530                                 }
 531 #else
 532                                 for (i = 0; i < TCP_SIGLEN; ++i)
 533                                         ND_PRINT((ndo, "%02x", cp[i]));
 534 #endif
 535                                 break;
 536
 537                         case TCPOPT_AUTH:
 538                                 ND_PRINT((ndo, "keyid %d", *cp++));
 539                                 datalen = len - 3;
 540                                 for (i = 0; i < datalen; ++i) {
 541                                         LENCHECK(i);
 542                                         ND_PRINT((ndo, "%02x", cp[i]));
 543                                 }
 544                                 break;
 545
 546
 547                         case TCPOPT_EOL:
 548                         case TCPOPT_NOP:
 549                         case TCPOPT_SACKOK:
 550                                 /*
 551                                  * Nothing interesting.
 552                                  * fall through
 553                                  */
 554                                 break;
 555
 556                         case TCPOPT_UTO:
 557                                 datalen = 2;
 558                                 LENCHECK(datalen);
 559                                 utoval = EXTRACT_16BITS(cp);
 560                                 ND_PRINT((ndo, "0x%x", utoval));
 561                                 if (utoval & 0x0001)
 562                                         utoval = (utoval >> 1) * 60;
 563                                 else
 564                                         utoval >>= 1;
 565                                 ND_PRINT((ndo, " %u", utoval));
 566                                 break;
 567
 568                         case TCPOPT_MPTCP:
 569                                 datalen = len - 2;
 570                                 LENCHECK(datalen);
 571                                 if (!mptcp_print(ndo, cp-2, len, flags))
 572                                         goto bad;
 573                                 break;
 574
 575                         case TCPOPT_FASTOPEN:
 576                                 datalen = len - 2;
 577                                 LENCHECK(datalen);
 578                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 579                                 break;
 580
 581                         case TCPOPT_EXPERIMENT2:
 582                                 datalen = len - 2;
 583                                 LENCHECK(datalen);
 584                                 if (datalen < 2)
 585                                         goto bad;
 586                                 /* RFC6994 */
 587                                 magic = EXTRACT_16BITS(cp);
 588                                 ND_PRINT((ndo, "-"));
 589
 590                                 switch(magic) {
 591
 592                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 593                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 594                                         break;
 595
 596                                 default:
 597                                         /* Unknown magic number */
 598                                         ND_PRINT((ndo, "%04x", magic));
 599                                         break;
 600                                 }
 601                                 break;
 602
 603                         default:
 604                                 datalen = len - 2;
 605                                 if (datalen)
 606                                         ND_PRINT((ndo, " 0x"));
 607                                 for (i = 0; i < datalen; ++i) {
 608                                         LENCHECK(i);
 609                                         ND_PRINT((ndo, "%02x", cp[i]));
 610                                 }
 611                                 break;
 612                         }
 613
 614                         /* Account for data printed */
 615                         cp += datalen;
 616                         hlen -= datalen;
 617
 618                         /* Check specification against observed length */
 619                         ++datalen;                      /* option octet */
 620                         if (!ZEROLENOPT(opt))
 621                                 ++datalen;              /* size octet */
 622                         if (datalen != len)
 623                                 ND_PRINT((ndo, "[len %d]", len));
 624                         ch = ',';
 625                         if (opt == TCPOPT_EOL)
 626                                 break;
 627                 }
 628                 ND_PRINT((ndo, "]"));
 629         }
 630
 631         /*
 632          * Print length field before crawling down the stack.
 633          */
 634         ND_PRINT((ndo, ", length %u", length));
 635
 636         if (length <= 0)
 637                 return;
 638
 639         /*
 640          * Decode payload if necessary.
 641          */
 642         bp += TH_OFF(tp) * 4;
 643         if ((flags & TH_RST) && ndo->ndo_vflag) {
 644                 print_tcp_rst_data(ndo, bp, length);
 645                 return;
 646         }
 647
 648         if (ndo->ndo_packettype) {
 649                 switch (ndo->ndo_packettype) {
 650                 case PT_ZMTP1:
 651                         zmtp1_print(ndo, bp, length);
 652                         break;
 653                 }
 654                 return;
 655         }
 656
 657         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 658                 telnet_print(ndo, bp, length);
 659         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 660                 ND_PRINT((ndo, ": "));
 661                 smtp_print(ndo, bp, length);
 662         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 663                 bgp_print(ndo, bp, length);
 664         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 665                 pptp_print(ndo, bp);
 666 #ifdef ENABLE_SMB
 667         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 668                 nbt_tcp_print(ndo, bp, length);
 669         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 670                 smb_tcp_print(ndo, bp, length);
 671 #endif
 672         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 673                 beep_print(ndo, bp, length);
 674         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 675                 openflow_print(ndo, bp, length);
 676         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 677                 ND_PRINT((ndo, ": "));
 678                 ftp_print(ndo, bp, length);
 679         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 680                 ND_PRINT((ndo, ": "));
 681                 http_print(ndo, bp, length);
 682         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 683                 ND_PRINT((ndo, ": "));
 684                 rtsp_print(ndo, bp, length);
 685         } else if (length > 2 &&
 686                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 687                 /*
 688                  * TCP DNS query has 2byte length at the head.
 689                  * XXX packet could be unaligned, it can go strange
 690                  */
 691                 ns_print(ndo, bp + 2, length - 2, 0);
 692         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 693                 msdp_print(ndo, bp, length);
 694         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 695                 rpki_rtr_print(ndo, bp, length);
 696         }
 697         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 698                 ldp_print(ndo, bp, length);
 699         }
 700         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 701                  length >= 4 && ND_TTEST2(*bp, 4)) {
 702                 /*
 703                  * If data present, header length valid, and NFS port used,
 704                  * assume NFS.
 705                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 706                  * to NFS print routines.
 707                  */
 708                 uint32_t fraglen;
 709                 register const struct sunrpc_msg *rp;
 710                 enum sunrpc_msg_type direction;
 711
 712                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 713                 if (fraglen > (length) - 4)
 714                         fraglen = (length) - 4;
 715                 rp = (const struct sunrpc_msg *)(bp + 4);
 716                 if (ND_TTEST(rp->rm_direction)) {
 717                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 718                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 719                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 720                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 721                                 return;
 722                         }
 723                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 724                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 725                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 726                                 return;
 727                         }
 728                 }
 729         }
 730
 731         return;
 732  bad:
 733         ND_PRINT((ndo, "[bad opt]"));
 734         if (ch != '\0')
 735                 ND_PRINT((ndo, ">"));
 736         return;
 737  trunc:
 738         ND_PRINT((ndo, "[|tcp]"));
 739         if (ch != '\0')
 740                 ND_PRINT((ndo, ">"));
 741 }
 742
 743 /*
 744  * RFC1122 says the following on data in RST segments:
 745  *
 746  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 747  *
 748  *            A TCP SHOULD allow a received RST segment to include data.
 749  *
 750  *            DISCUSSION
 751  *                 It has been suggested that a RST segment could contain
 752  *                 ASCII text that encoded and explained the cause of the
 753  *                 RST.  No standard has yet been established for such
 754  *                 data.
 755  *
 756  */
 757
 758 static void
 759 print_tcp_rst_data(netdissect_options *ndo,
 760                    register const u_char *sp, u_int length)
 761 {
 762         int c;
 763
 764         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 765         if (length > MAX_RST_DATA_LEN) {
 766                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 767                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 768         }
 769         ND_PRINT((ndo, " "));
 770         while (length-- && sp < ndo->ndo_snapend) {
 771                 c = *sp++;
 772                 safeputchar(ndo, c);
 773         }
 774         ND_PRINT((ndo, "]"));
 775 }
 776
 777 static void
 778 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 779                           u_int datalen, int exp)
 780 {
 781         u_int i;
 782
 783         if (exp)
 784                 ND_PRINT((ndo, "tfo"));
 785
 786         if (datalen == 0) {
 787                 /* Fast Open Cookie Request */
 788                 ND_PRINT((ndo, " cookiereq"));
 789         } else {
 790                 /* Fast Open Cookie */
 791                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 792                         ND_PRINT((ndo, " invalid"));
 793                 } else {
 794                         ND_PRINT((ndo, " cookie "));
 795                         for (i = 0; i < datalen; ++i)
 796                                 ND_PRINT((ndo, "%02x", cp[i]));
 797                 }
 798         }
 799 }
 800
 801 #ifdef HAVE_LIBCRYPTO
 802 USES_APPLE_DEPRECATED_API
 803 static int
 804 tcp_verify_signature(netdissect_options *ndo,
 805                      const struct ip *ip, const struct tcphdr *tp,
 806                      const u_char *data, int length, const u_char *rcvsig)
 807 {
 808         struct tcphdr tp1;
 809         u_char sig[TCP_SIGLEN];
 810         char zero_proto = 0;
 811         MD5_CTX ctx;
 812         uint16_t savecsum, tlen;
 813         const struct ip6_hdr *ip6;
 814         uint32_t len32;
 815         uint8_t nxt;
 816
 817         if (data + length > ndo->ndo_snapend) {
 818                 ND_PRINT((ndo, "snaplen too short, "));
 819                 return (CANT_CHECK_SIGNATURE);
 820         }
 821
 822         tp1 = *tp;
 823
 824         if (ndo->ndo_sigsecret == NULL) {
 825                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 826                 return (CANT_CHECK_SIGNATURE);
 827         }
 828
 829         MD5_Init(&ctx);
 830         /*
 831          * Step 1: Update MD5 hash with IP pseudo-header.
 832          */
 833         if (IP_V(ip) == 4) {
 834                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 835                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 836                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 837                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 838                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 839                 tlen = htons(tlen);
 840                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 841         } else if (IP_V(ip) == 6) {
 842                 ip6 = (const struct ip6_hdr *)ip;
 843                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 844                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 845                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 846                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 847                 nxt = 0;
 848                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 849                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 850                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 851                 nxt = IPPROTO_TCP;
 852                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 853         } else {
 854                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 855                 return (CANT_CHECK_SIGNATURE);
 856         }
 857
 858         /*
 859          * Step 2: Update MD5 hash with TCP header, excluding options.
 860          * The TCP checksum must be set to zero.
 861          */
 862         savecsum = tp1.th_sum;
 863         tp1.th_sum = 0;
 864         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 865         tp1.th_sum = savecsum;
 866         /*
 867          * Step 3: Update MD5 hash with TCP segment data, if present.
 868          */
 869         if (length > 0)
 870                 MD5_Update(&ctx, data, length);
 871         /*
 872          * Step 4: Update MD5 hash with shared secret.
 873          */
 874         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 875         MD5_Final(sig, &ctx);
 876
 877         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 878                 return (SIGNATURE_VALID);
 879         else
 880                 return (SIGNATURE_INVALID);
 881 }
 882 USES_APPLE_RST
 883 #endif /* HAVE_LIBCRYPTO */
 884
 885 /*
 886  * Local Variables:
 887  * c-style: whitesmith
 888  * c-basic-offset: 8
 889  * End:
 890  */