The Tcpdump Group git mirrors - tcpdump/blob - print-tcp.c

   1 /*      $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Copyright (c) 1999-2004 The tcpdump.org project
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that: (1) source code distributions
  11  * retain the above copyright notice and this paragraph in its entirety, (2)
  12  * distributions including binary code include the above copyright notice and
  13  * this paragraph in its entirety in the documentation or other materials
  14  * provided with the distribution, and (3) all advertising materials mentioning
  15  * features or use of this software display the following acknowledgement:
  16  * ``This product includes software developed by the University of California,
  17  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  18  * the University nor the names of its contributors may be used to endorse
  19  * or promote products derived from this software without specific prior
  20  * written permission.
  21  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  24  */
  25
  26 #ifndef lint
  27 #else
  28 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
  29 #endif
  30
  31 #ifdef HAVE_CONFIG_H
  32 #include "config.h"
  33 #endif
  34
  35 #include <tcpdump-stdinc.h>
  36
  37 #include <stdlib.h>
  38 #include <string.h>
  39
  40 #include "interface.h"
  41 #include "addrtoname.h"
  42 #include "extract.h"
  43
  44 #include "tcp.h"
  45
  46 #include "ip.h"
  47 #ifdef INET6
  48 #include "ip6.h"
  49 #endif
  50 #include "ipproto.h"
  51 #include "rpc_auth.h"
  52 #include "rpc_msg.h"
  53
  54 #ifdef HAVE_LIBCRYPTO
  55 #include <openssl/md5.h>
  56 #include "signature.h"
  57
  58 static int tcp_verify_signature(netdissect_options *ndo,
  59                                 const struct ip *ip, const struct tcphdr *tp,
  60                                 const u_char *data, int length, const u_char *rcvsig);
  61 #endif
  62
  63 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
  64 static void print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
  65                                       u_int datalen, int exp);
  66
  67 #define MAX_RST_DATA_LEN        30
  68
  69
  70 struct tha {
  71         struct in_addr src;
  72         struct in_addr dst;
  73         u_int port;
  74 };
  75
  76 struct tcp_seq_hash {
  77         struct tcp_seq_hash *nxt;
  78         struct tha addr;
  79         tcp_seq seq;
  80         tcp_seq ack;
  81 };
  82
  83 #ifdef INET6
  84 struct tha6 {
  85         struct in6_addr src;
  86         struct in6_addr dst;
  87         u_int port;
  88 };
  89
  90 struct tcp_seq_hash6 {
  91         struct tcp_seq_hash6 *nxt;
  92         struct tha6 addr;
  93         tcp_seq seq;
  94         tcp_seq ack;
  95 };
  96 #endif
  97
  98 #define TSEQ_HASHSIZE 919
  99
 100 /* These tcp optinos do not have the size octet */
 101 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 102
 103 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 104 #ifdef INET6
 105 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 106 #endif
 107
 108 static const struct tok tcp_flag_values[] = {
 109         { TH_FIN, "F" },
 110         { TH_SYN, "S" },
 111         { TH_RST, "R" },
 112         { TH_PUSH, "P" },
 113         { TH_ACK, "." },
 114         { TH_URG, "U" },
 115         { TH_ECNECHO, "E" },
 116         { TH_CWR, "W" },
 117         { 0, NULL }
 118 };
 119
 120 static const struct tok tcp_option_values[] = {
 121         { TCPOPT_EOL, "eol" },
 122         { TCPOPT_NOP, "nop" },
 123         { TCPOPT_MAXSEG, "mss" },
 124         { TCPOPT_WSCALE, "wscale" },
 125         { TCPOPT_SACKOK, "sackOK" },
 126         { TCPOPT_SACK, "sack" },
 127         { TCPOPT_ECHO, "echo" },
 128         { TCPOPT_ECHOREPLY, "echoreply" },
 129         { TCPOPT_TIMESTAMP, "TS" },
 130         { TCPOPT_CC, "cc" },
 131         { TCPOPT_CCNEW, "ccnew" },
 132         { TCPOPT_CCECHO, "" },
 133         { TCPOPT_SIGNATURE, "md5" },
 134         { TCPOPT_AUTH, "enhanced auth" },
 135         { TCPOPT_UTO, "uto" },
 136         { TCPOPT_MPTCP, "mptcp" },
 137         { TCPOPT_FASTOPEN, "tfo" },
 138         { TCPOPT_EXPERIMENT2, "exp" },
 139         { 0, NULL }
 140 };
 141
 142 static int
 143 tcp_cksum(netdissect_options *ndo,
 144           register const struct ip *ip,
 145           register const struct tcphdr *tp,
 146           register u_int len)
 147 {
 148         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 149                                 IPPROTO_TCP);
 150 }
 151
 152 void
 153 tcp_print(netdissect_options *ndo,
 154           register const u_char *bp, register u_int length,
 155           register const u_char *bp2, int fragmented)
 156 {
 157         register const struct tcphdr *tp;
 158         register const struct ip *ip;
 159         register u_char flags;
 160         register u_int hlen;
 161         register char ch;
 162         uint16_t sport, dport, win, urp;
 163         uint32_t seq, ack, thseq, thack;
 164         u_int utoval;
 165         uint16_t magic;
 166         register int rev;
 167 #ifdef INET6
 168         register const struct ip6_hdr *ip6;
 169 #endif
 170
 171         tp = (const struct tcphdr *)bp;
 172         ip = (const struct ip *)bp2;
 173 #ifdef INET6
 174         if (IP_V(ip) == 6)
 175                 ip6 = (const struct ip6_hdr *)bp2;
 176         else
 177                 ip6 = NULL;
 178 #endif /*INET6*/
 179         ch = '\0';
 180         if (!ND_TTEST(tp->th_dport)) {
 181                 ND_PRINT((ndo, "%s > %s: [|tcp]",
 182                              ipaddr_string(ndo, &ip->ip_src),
 183                              ipaddr_string(ndo, &ip->ip_dst)));
 184                 return;
 185         }
 186
 187         sport = EXTRACT_16BITS(&tp->th_sport);
 188         dport = EXTRACT_16BITS(&tp->th_dport);
 189
 190         hlen = TH_OFF(tp) * 4;
 191
 192 #ifdef INET6
 193         if (ip6) {
 194                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 195                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 196                                      ip6addr_string(ndo, &ip6->ip6_src),
 197                                      tcpport_string(sport),
 198                                      ip6addr_string(ndo, &ip6->ip6_dst),
 199                                      tcpport_string(dport)));
 200                 } else {
 201                         ND_PRINT((ndo, "%s > %s: ",
 202                                      tcpport_string(sport), tcpport_string(dport)));
 203                 }
 204         } else
 205 #endif /*INET6*/
 206         {
 207                 if (ip->ip_p == IPPROTO_TCP) {
 208                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 209                                      ipaddr_string(ndo, &ip->ip_src),
 210                                      tcpport_string(sport),
 211                                      ipaddr_string(ndo, &ip->ip_dst),
 212                                      tcpport_string(dport)));
 213                 } else {
 214                         ND_PRINT((ndo, "%s > %s: ",
 215                                      tcpport_string(sport), tcpport_string(dport)));
 216                 }
 217         }
 218
 219         if (hlen < sizeof(*tp)) {
 220                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 221                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 222                 return;
 223         }
 224
 225         ND_TCHECK(*tp);
 226
 227         seq = EXTRACT_32BITS(&tp->th_seq);
 228         ack = EXTRACT_32BITS(&tp->th_ack);
 229         win = EXTRACT_16BITS(&tp->th_win);
 230         urp = EXTRACT_16BITS(&tp->th_urp);
 231
 232         if (ndo->ndo_qflag) {
 233                 ND_PRINT((ndo, "tcp %d", length - hlen));
 234                 if (hlen > length) {
 235                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 236                                      hlen, length));
 237                 }
 238                 return;
 239         }
 240
 241         flags = tp->th_flags;
 242         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
 243
 244         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
 245                 /*
 246                  * Find (or record) the initial sequence numbers for
 247                  * this conversation.  (we pick an arbitrary
 248                  * collating order so there's only one entry for
 249                  * both directions).
 250                  */
 251                 rev = 0;
 252 #ifdef INET6
 253                 if (ip6) {
 254                         register struct tcp_seq_hash6 *th;
 255                         struct tcp_seq_hash6 *tcp_seq_hash;
 256                         const struct in6_addr *src, *dst;
 257                         struct tha6 tha;
 258
 259                         tcp_seq_hash = tcp_seq_hash6;
 260                         src = &ip6->ip6_src;
 261                         dst = &ip6->ip6_dst;
 262                         if (sport > dport)
 263                                 rev = 1;
 264                         else if (sport == dport) {
 265                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 266                                         rev = 1;
 267                         }
 268                         if (rev) {
 269                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 270                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 271                                 tha.port = dport << 16 | sport;
 272                         } else {
 273                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 274                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 275                                 tha.port = sport << 16 | dport;
 276                         }
 277
 278                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 279                              th->nxt; th = th->nxt)
 280                                 if (memcmp((char *)&tha, (char *)&th->addr,
 281                                            sizeof(th->addr)) == 0)
 282                                         break;
 283
 284                         if (!th->nxt || (flags & TH_SYN)) {
 285                                 /* didn't find it or new conversation */
 286                                 if (th->nxt == NULL) {
 287                                         th->nxt = (struct tcp_seq_hash6 *)
 288                                                 calloc(1, sizeof(*th));
 289                                         if (th->nxt == NULL)
 290                                                 error("tcp_print: calloc");
 291                                 }
 292                                 th->addr = tha;
 293                                 if (rev)
 294                                         th->ack = seq, th->seq = ack - 1;
 295                                 else
 296                                         th->seq = seq, th->ack = ack - 1;
 297                         } else {
 298                                 if (rev)
 299                                         seq -= th->ack, ack -= th->seq;
 300                                 else
 301                                         seq -= th->seq, ack -= th->ack;
 302                         }
 303
 304                         thseq = th->seq;
 305                         thack = th->ack;
 306                 } else {
 307 #else  /*INET6*/
 308                 {
 309 #endif /*INET6*/
 310                         register struct tcp_seq_hash *th;
 311                         struct tcp_seq_hash *tcp_seq_hash;
 312                         const struct in_addr *src, *dst;
 313                         struct tha tha;
 314
 315                         tcp_seq_hash = tcp_seq_hash4;
 316                         src = &ip->ip_src;
 317                         dst = &ip->ip_dst;
 318                         if (sport > dport)
 319                                 rev = 1;
 320                         else if (sport == dport) {
 321                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip->ip_dst) > 0)
 322                                         rev = 1;
 323                         }
 324                         if (rev) {
 325                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip->ip_dst);
 326                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip->ip_src);
 327                                 tha.port = dport << 16 | sport;
 328                         } else {
 329                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip->ip_dst);
 330                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip->ip_src);
 331                                 tha.port = sport << 16 | dport;
 332                         }
 333
 334                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 335                              th->nxt; th = th->nxt)
 336                                 if (memcmp((char *)&tha, (char *)&th->addr,
 337                                            sizeof(th->addr)) == 0)
 338                                         break;
 339
 340                         if (!th->nxt || (flags & TH_SYN)) {
 341                                 /* didn't find it or new conversation */
 342                                 if (th->nxt == NULL) {
 343                                         th->nxt = (struct tcp_seq_hash *)
 344                                                 calloc(1, sizeof(*th));
 345                                         if (th->nxt == NULL)
 346                                                 error("tcp_print: calloc");
 347                                 }
 348                                 th->addr = tha;
 349                                 if (rev)
 350                                         th->ack = seq, th->seq = ack - 1;
 351                                 else
 352                                         th->seq = seq, th->ack = ack - 1;
 353                         } else {
 354                                 if (rev)
 355                                         seq -= th->ack, ack -= th->seq;
 356                                 else
 357                                         seq -= th->seq, ack -= th->ack;
 358                         }
 359
 360                         thseq = th->seq;
 361                         thack = th->ack;
 362                 }
 363         } else {
 364                 /*fool gcc*/
 365                 thseq = thack = rev = 0;
 366         }
 367         if (hlen > length) {
 368                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 369                              hlen, length));
 370                 return;
 371         }
 372
 373         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 374                 /* Check the checksum, if possible. */
 375                 uint16_t sum, tcp_sum;
 376
 377                 if (IP_V(ip) == 4) {
 378                         if (ND_TTEST2(tp->th_sport, length)) {
 379                                 sum = tcp_cksum(ndo, ip, tp, length);
 380                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 381
 382                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 383                                 if (sum != 0)
 384                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 385                                             in_cksum_shouldbe(tcp_sum, sum)));
 386                                 else
 387                                         ND_PRINT((ndo, " (correct)"));
 388                         }
 389                 }
 390 #ifdef INET6
 391                 else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 392                         if (ND_TTEST2(tp->th_sport, length)) {
 393                                 sum = nextproto6_cksum(ip6, (const uint8_t *)tp,
 394                                                         length, length, IPPROTO_TCP);
 395                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 396
 397                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 398                                 if (sum != 0)
 399                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 400                                             in_cksum_shouldbe(tcp_sum, sum)));
 401                                 else
 402                                         ND_PRINT((ndo, " (correct)"));
 403
 404                         }
 405                 }
 406 #endif
 407         }
 408
 409         length -= hlen;
 410         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 411                 ND_PRINT((ndo, ", seq %u", seq));
 412
 413                 if (length > 0) {
 414                         ND_PRINT((ndo, ":%u", seq + length));
 415                 }
 416         }
 417
 418         if (flags & TH_ACK) {
 419                 ND_PRINT((ndo, ", ack %u", ack));
 420         }
 421
 422         ND_PRINT((ndo, ", win %d", win));
 423
 424         if (flags & TH_URG)
 425                 ND_PRINT((ndo, ", urg %d", urp));
 426         /*
 427          * Handle any options.
 428          */
 429         if (hlen > sizeof(*tp)) {
 430                 register const u_char *cp;
 431                 register u_int i, opt, datalen;
 432                 register u_int len;
 433
 434                 hlen -= sizeof(*tp);
 435                 cp = (const u_char *)tp + sizeof(*tp);
 436                 ND_PRINT((ndo, ", options ["));
 437                 while (hlen > 0) {
 438                         if (ch != '\0')
 439                                 ND_PRINT((ndo, "%c", ch));
 440                         ND_TCHECK(*cp);
 441                         opt = *cp++;
 442                         if (ZEROLENOPT(opt))
 443                                 len = 1;
 444                         else {
 445                                 ND_TCHECK(*cp);
 446                                 len = *cp++;    /* total including type, len */
 447                                 if (len < 2 || len > hlen)
 448                                         goto bad;
 449                                 --hlen;         /* account for length byte */
 450                         }
 451                         --hlen;                 /* account for type byte */
 452                         datalen = 0;
 453
 454 /* Bail if "l" bytes of data are not left or were not captured  */
 455 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 456
 457
 458                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 459
 460                         switch (opt) {
 461
 462                         case TCPOPT_MAXSEG:
 463                                 datalen = 2;
 464                                 LENCHECK(datalen);
 465                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 466                                 break;
 467
 468                         case TCPOPT_WSCALE:
 469                                 datalen = 1;
 470                                 LENCHECK(datalen);
 471                                 ND_PRINT((ndo, " %u", *cp));
 472                                 break;
 473
 474                         case TCPOPT_SACK:
 475                                 datalen = len - 2;
 476                                 if (datalen % 8 != 0) {
 477                                         ND_PRINT((ndo, "malformed sack"));
 478                                 } else {
 479                                         uint32_t s, e;
 480
 481                                         ND_PRINT((ndo, " %d ", datalen / 8));
 482                                         for (i = 0; i < datalen; i += 8) {
 483                                                 LENCHECK(i + 4);
 484                                                 s = EXTRACT_32BITS(cp + i);
 485                                                 LENCHECK(i + 8);
 486                                                 e = EXTRACT_32BITS(cp + i + 4);
 487                                                 if (rev) {
 488                                                         s -= thseq;
 489                                                         e -= thseq;
 490                                                 } else {
 491                                                         s -= thack;
 492                                                         e -= thack;
 493                                                 }
 494                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 495                                         }
 496                                 }
 497                                 break;
 498
 499                         case TCPOPT_CC:
 500                         case TCPOPT_CCNEW:
 501                         case TCPOPT_CCECHO:
 502                         case TCPOPT_ECHO:
 503                         case TCPOPT_ECHOREPLY:
 504
 505                                 /*
 506                                  * those options share their semantics.
 507                                  * fall through
 508                                  */
 509                                 datalen = 4;
 510                                 LENCHECK(datalen);
 511                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 512                                 break;
 513
 514                         case TCPOPT_TIMESTAMP:
 515                                 datalen = 8;
 516                                 LENCHECK(datalen);
 517                                 ND_PRINT((ndo, " val %u ecr %u",
 518                                              EXTRACT_32BITS(cp),
 519                                              EXTRACT_32BITS(cp + 4)));
 520                                 break;
 521
 522                         case TCPOPT_SIGNATURE:
 523                                 datalen = TCP_SIGLEN;
 524                                 LENCHECK(datalen);
 525 #ifdef HAVE_LIBCRYPTO
 526                                 switch (tcp_verify_signature(ndo, ip, tp,
 527                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 528
 529                                 case SIGNATURE_VALID:
 530                                         ND_PRINT((ndo, "valid"));
 531                                         break;
 532
 533                                 case SIGNATURE_INVALID:
 534                                         ND_PRINT((ndo, "invalid"));
 535                                         break;
 536
 537                                 case CANT_CHECK_SIGNATURE:
 538                                         ND_PRINT((ndo, "can't check - "));
 539                                         for (i = 0; i < TCP_SIGLEN; ++i)
 540                                                 ND_PRINT((ndo, "%02x", cp[i]));
 541                                         break;
 542                                 }
 543 #else
 544                                 for (i = 0; i < TCP_SIGLEN; ++i)
 545                                         ND_PRINT((ndo, "%02x", cp[i]));
 546 #endif
 547                                 break;
 548
 549                         case TCPOPT_AUTH:
 550                                 ND_PRINT((ndo, "keyid %d", *cp++));
 551                                 datalen = len - 3;
 552                                 for (i = 0; i < datalen; ++i) {
 553                                         LENCHECK(i);
 554                                         ND_PRINT((ndo, "%02x", cp[i]));
 555                                 }
 556                                 break;
 557
 558
 559                         case TCPOPT_EOL:
 560                         case TCPOPT_NOP:
 561                         case TCPOPT_SACKOK:
 562                                 /*
 563                                  * Nothing interesting.
 564                                  * fall through
 565                                  */
 566                                 break;
 567
 568                         case TCPOPT_UTO:
 569                                 datalen = 2;
 570                                 LENCHECK(datalen);
 571                                 utoval = EXTRACT_16BITS(cp);
 572                                 ND_PRINT((ndo, "0x%x", utoval));
 573                                 if (utoval & 0x0001)
 574                                         utoval = (utoval >> 1) * 60;
 575                                 else
 576                                         utoval >>= 1;
 577                                 ND_PRINT((ndo, " %u", utoval));
 578                                 break;
 579
 580                         case TCPOPT_MPTCP:
 581                                 datalen = len - 2;
 582                                 LENCHECK(datalen);
 583                                 if (!mptcp_print(ndo, cp-2, len, flags))
 584                                         goto bad;
 585                                 break;
 586
 587                         case TCPOPT_FASTOPEN:
 588                                 datalen = len - 2;
 589                                 LENCHECK(datalen);
 590                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 591                                 break;
 592
 593                         case TCPOPT_EXPERIMENT2:
 594                                 datalen = len - 2;
 595                                 LENCHECK(datalen);
 596                                 if (datalen < 2)
 597                                         goto bad;
 598                                 /* RFC6994 */
 599                                 magic = EXTRACT_16BITS(cp);
 600                                 ND_PRINT((ndo, "-"));
 601
 602                                 switch(magic) {
 603
 604                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 605                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 606                                         break;
 607
 608                                 default:
 609                                         /* Unknown magic number */
 610                                         ND_PRINT((ndo, "%04x", magic));
 611                                         break;
 612                                 }
 613                                 break;
 614
 615                         default:
 616                                 datalen = len - 2;
 617                                 if (datalen)
 618                                         ND_PRINT((ndo, " 0x"));
 619                                 for (i = 0; i < datalen; ++i) {
 620                                         LENCHECK(i);
 621                                         ND_PRINT((ndo, "%02x", cp[i]));
 622                                 }
 623                                 break;
 624                         }
 625
 626                         /* Account for data printed */
 627                         cp += datalen;
 628                         hlen -= datalen;
 629
 630                         /* Check specification against observed length */
 631                         ++datalen;                      /* option octet */
 632                         if (!ZEROLENOPT(opt))
 633                                 ++datalen;              /* size octet */
 634                         if (datalen != len)
 635                                 ND_PRINT((ndo, "[len %d]", len));
 636                         ch = ',';
 637                         if (opt == TCPOPT_EOL)
 638                                 break;
 639                 }
 640                 ND_PRINT((ndo, "]"));
 641         }
 642
 643         /*
 644          * Print length field before crawling down the stack.
 645          */
 646         ND_PRINT((ndo, ", length %u", length));
 647
 648         if (length <= 0)
 649                 return;
 650
 651         /*
 652          * Decode payload if necessary.
 653          */
 654         bp += TH_OFF(tp) * 4;
 655         if ((flags & TH_RST) && ndo->ndo_vflag) {
 656                 print_tcp_rst_data(ndo, bp, length);
 657                 return;
 658         }
 659
 660         if (ndo->ndo_packettype) {
 661                 switch (ndo->ndo_packettype) {
 662                 case PT_ZMTP1:
 663                         zmtp1_print(ndo, bp, length);
 664                         break;
 665                 }
 666                 return;
 667         }
 668
 669         if (sport == TELNET_PORT || dport == TELNET_PORT) {
 670                 telnet_print(ndo, bp, length);
 671         } else if (sport == SMTP_PORT || dport == SMTP_PORT) {
 672                 ND_PRINT((ndo, ": "));
 673                 smtp_print(ndo, bp, length);
 674         } else if (sport == BGP_PORT || dport == BGP_PORT)
 675                 bgp_print(ndo, bp, length);
 676         else if (sport == PPTP_PORT || dport == PPTP_PORT)
 677                 pptp_print(ndo, bp);
 678 #ifdef TCPDUMP_DO_SMB
 679         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 680                 nbt_tcp_print(ndo, bp, length);
 681         else if (sport == SMB_PORT || dport == SMB_PORT)
 682                 smb_tcp_print(ndo, bp, length);
 683 #endif
 684         else if (sport == BEEP_PORT || dport == BEEP_PORT)
 685                 beep_print(ndo, bp, length);
 686         else if (sport == OPENFLOW_PORT_OLD || dport == OPENFLOW_PORT_OLD ||
 687                  sport == OPENFLOW_PORT_IANA || dport == OPENFLOW_PORT_IANA)
 688                 openflow_print(ndo, bp, length);
 689         else if (sport == FTP_PORT || dport == FTP_PORT) {
 690                 ND_PRINT((ndo, ": "));
 691                 ftp_print(ndo, bp, length);
 692         } else if (sport == HTTP_PORT || dport == HTTP_PORT ||
 693             sport == HTTP_PORT_ALT || dport == HTTP_PORT_ALT) {
 694                 ND_PRINT((ndo, ": "));
 695                 http_print(ndo, bp, length);
 696         } else if (sport == RTSP_PORT || dport == RTSP_PORT ||
 697             sport == RTSP_PORT_ALT || dport == RTSP_PORT_ALT) {
 698                 ND_PRINT((ndo, ": "));
 699                 rtsp_print(ndo, bp, length);
 700         } else if (length > 2 &&
 701                  (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT)) {
 702                 /*
 703                  * TCP DNS query has 2byte length at the head.
 704                  * XXX packet could be unaligned, it can go strange
 705                  */
 706                 ns_print(ndo, bp + 2, length - 2, 0);
 707         } else if (sport == MSDP_PORT || dport == MSDP_PORT) {
 708                 msdp_print(ndo, bp, length);
 709         } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) {
 710                 rpki_rtr_print(ndo, bp, length);
 711         }
 712         else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) {
 713                 ldp_print(ndo, bp, length);
 714         }
 715         else if ((sport == NFS_PORT || dport == NFS_PORT) &&
 716                  length >= 4 && ND_TTEST2(*bp, 4)) {
 717                 /*
 718                  * If data present, header length valid, and NFS port used,
 719                  * assume NFS.
 720                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 721                  * to NFS print routines.
 722                  */
 723                 uint32_t fraglen;
 724                 register const struct sunrpc_msg *rp;
 725                 enum sunrpc_msg_type direction;
 726
 727                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 728                 if (fraglen > (length) - 4)
 729                         fraglen = (length) - 4;
 730                 rp = (const struct sunrpc_msg *)(bp + 4);
 731                 if (ND_TTEST(rp->rm_direction)) {
 732                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 733                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 734                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 735                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 736                                 return;
 737                         }
 738                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 739                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 740                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 741                                 return;
 742                         }
 743                 }
 744         }
 745
 746         return;
 747  bad:
 748         ND_PRINT((ndo, "[bad opt]"));
 749         if (ch != '\0')
 750                 ND_PRINT((ndo, ">"));
 751         return;
 752  trunc:
 753         ND_PRINT((ndo, "[|tcp]"));
 754         if (ch != '\0')
 755                 ND_PRINT((ndo, ">"));
 756 }
 757
 758 /*
 759  * RFC1122 says the following on data in RST segments:
 760  *
 761  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 762  *
 763  *            A TCP SHOULD allow a received RST segment to include data.
 764  *
 765  *            DISCUSSION
 766  *                 It has been suggested that a RST segment could contain
 767  *                 ASCII text that encoded and explained the cause of the
 768  *                 RST.  No standard has yet been established for such
 769  *                 data.
 770  *
 771  */
 772
 773 static void
 774 print_tcp_rst_data(netdissect_options *ndo,
 775                    register const u_char *sp, u_int length)
 776 {
 777         int c;
 778
 779         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 780         if (length > MAX_RST_DATA_LEN) {
 781                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 782                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 783         }
 784         ND_PRINT((ndo, " "));
 785         while (length-- && sp <= ndo->ndo_snapend) {
 786                 c = *sp++;
 787                 safeputchar(ndo, c);
 788         }
 789         ND_PRINT((ndo, "]"));
 790 }
 791
 792 static void
 793 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 794                           u_int datalen, int exp)
 795 {
 796         u_int i;
 797
 798         if (exp)
 799                 ND_PRINT((ndo, "tfo"));
 800
 801         if (datalen == 0) {
 802                 /* Fast Open Cookie Request */
 803                 ND_PRINT((ndo, " cookiereq"));
 804         } else {
 805                 /* Fast Open Cookie */
 806                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 807                         ND_PRINT((ndo, " malformed"));
 808                 } else {
 809                         ND_PRINT((ndo, " cookie "));
 810                         for (i = 0; i < datalen; ++i)
 811                                 ND_PRINT((ndo, "%02x", cp[i]));
 812                 }
 813         }
 814 }
 815
 816 #ifdef HAVE_LIBCRYPTO
 817 USES_APPLE_DEPRECATED_API
 818 static int
 819 tcp_verify_signature(netdissect_options *ndo,
 820                      const struct ip *ip, const struct tcphdr *tp,
 821                      const u_char *data, int length, const u_char *rcvsig)
 822 {
 823         struct tcphdr tp1;
 824         u_char sig[TCP_SIGLEN];
 825         char zero_proto = 0;
 826         MD5_CTX ctx;
 827         uint16_t savecsum, tlen;
 828 #ifdef INET6
 829         const struct ip6_hdr *ip6;
 830         uint32_t len32;
 831         uint8_t nxt;
 832 #endif
 833
 834         if (data + length > ndo->ndo_snapend) {
 835                 ND_PRINT((ndo, "snaplen too short, "));
 836                 return (CANT_CHECK_SIGNATURE);
 837         }
 838
 839         tp1 = *tp;
 840
 841         if (ndo->ndo_sigsecret == NULL) {
 842                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 843                 return (CANT_CHECK_SIGNATURE);
 844         }
 845
 846         MD5_Init(&ctx);
 847         /*
 848          * Step 1: Update MD5 hash with IP pseudo-header.
 849          */
 850         if (IP_V(ip) == 4) {
 851                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 852                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 853                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 854                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 855                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 856                 tlen = htons(tlen);
 857                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 858 #ifdef INET6
 859         } else if (IP_V(ip) == 6) {
 860                 ip6 = (const struct ip6_hdr *)ip;
 861                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 862                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 863                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 864                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 865                 nxt = 0;
 866                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 867                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 868                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 869                 nxt = IPPROTO_TCP;
 870                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 871 #endif
 872         } else {
 873 #ifdef INET6
 874                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 875 #else
 876                 ND_PRINT((ndo, "IP version not 4, "));
 877 #endif
 878                 return (CANT_CHECK_SIGNATURE);
 879         }
 880
 881         /*
 882          * Step 2: Update MD5 hash with TCP header, excluding options.
 883          * The TCP checksum must be set to zero.
 884          */
 885         savecsum = tp1.th_sum;
 886         tp1.th_sum = 0;
 887         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 888         tp1.th_sum = savecsum;
 889         /*
 890          * Step 3: Update MD5 hash with TCP segment data, if present.
 891          */
 892         if (length > 0)
 893                 MD5_Update(&ctx, data, length);
 894         /*
 895          * Step 4: Update MD5 hash with shared secret.
 896          */
 897         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 898         MD5_Final(sig, &ctx);
 899
 900         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 901                 return (SIGNATURE_VALID);
 902         else
 903                 return (SIGNATURE_INVALID);
 904 }
 905 USES_APPLE_RST
 906 #endif /* HAVE_LIBCRYPTO */
 907
 908 /*
 909  * Local Variables:
 910  * c-style: whitesmith
 911  * c-basic-offset: 8
 912  * End:
 913  */