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