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