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

   1 /*      $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $     */
   2
   3 /*
   4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * Copyright (c) 1999-2004 The tcpdump.org project
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that: (1) source code distributions
  11  * retain the above copyright notice and this paragraph in its entirety, (2)
  12  * distributions including binary code include the above copyright notice and
  13  * this paragraph in its entirety in the documentation or other materials
  14  * provided with the distribution, and (3) all advertising materials mentioning
  15  * features or use of this software display the following acknowledgement:
  16  * ``This product includes software developed by the University of California,
  17  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  18  * the University nor the names of its contributors may be used to endorse
  19  * or promote products derived from this software without specific prior
  20  * written permission.
  21  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  22  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  24  */
  25
  26 /* \summary: TCP printer */
  27
  28 #ifndef lint
  29 #else
  30 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
  31 #endif
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include "config.h"
  35 #endif
  36
  37 #include <netdissect-stdinc.h>
  38
  39 #include <stdlib.h>
  40 #include <string.h>
  41
  42 #include "netdissect.h"
  43 #include "addrtoname.h"
  44 #include "extract.h"
  45
  46 #include "tcp.h"
  47
  48 #include "ip.h"
  49 #include "ip6.h"
  50 #include "ipproto.h"
  51 #include "rpc_auth.h"
  52 #include "rpc_msg.h"
  53
  54 #ifdef HAVE_LIBCRYPTO
  55 #include <openssl/md5.h>
  56 #include "signature.h"
  57
  58 static int tcp_verify_signature(netdissect_options *ndo,
  59                                 const struct ip *ip, const struct tcphdr *tp,
  60                                 const u_char *data, int length, const u_char *rcvsig);
  61 #endif
  62
  63 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
  64 static void print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
  65                                       u_int datalen, int exp);
  66
  67 #define MAX_RST_DATA_LEN        30
  68
  69
  70 struct tha {
  71         struct in_addr src;
  72         struct in_addr dst;
  73         u_int port;
  74 };
  75
  76 struct tcp_seq_hash {
  77         struct tcp_seq_hash *nxt;
  78         struct tha addr;
  79         tcp_seq seq;
  80         tcp_seq ack;
  81 };
  82
  83 struct tha6 {
  84         struct in6_addr src;
  85         struct in6_addr dst;
  86         u_int port;
  87 };
  88
  89 struct tcp_seq_hash6 {
  90         struct tcp_seq_hash6 *nxt;
  91         struct tha6 addr;
  92         tcp_seq seq;
  93         tcp_seq ack;
  94 };
  95
  96 #define TSEQ_HASHSIZE 919
  97
  98 /* These tcp optinos do not have the size octet */
  99 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 100
 101 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
 102 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
 103
 104 static const struct tok tcp_flag_values[] = {
 105         { TH_FIN, "F" },
 106         { TH_SYN, "S" },
 107         { TH_RST, "R" },
 108         { TH_PUSH, "P" },
 109         { TH_ACK, "." },
 110         { TH_URG, "U" },
 111         { TH_ECNECHO, "E" },
 112         { TH_CWR, "W" },
 113         { 0, NULL }
 114 };
 115
 116 static const struct tok tcp_option_values[] = {
 117         { TCPOPT_EOL, "eol" },
 118         { TCPOPT_NOP, "nop" },
 119         { TCPOPT_MAXSEG, "mss" },
 120         { TCPOPT_WSCALE, "wscale" },
 121         { TCPOPT_SACKOK, "sackOK" },
 122         { TCPOPT_SACK, "sack" },
 123         { TCPOPT_ECHO, "echo" },
 124         { TCPOPT_ECHOREPLY, "echoreply" },
 125         { TCPOPT_TIMESTAMP, "TS" },
 126         { TCPOPT_CC, "cc" },
 127         { TCPOPT_CCNEW, "ccnew" },
 128         { TCPOPT_CCECHO, "" },
 129         { TCPOPT_SIGNATURE, "md5" },
 130         { TCPOPT_SCPS, "scps" },
 131         { TCPOPT_UTO, "uto" },
 132         { TCPOPT_AUTH, "enhanced auth" },
 133         { TCPOPT_MPTCP, "mptcp" },
 134         { TCPOPT_FASTOPEN, "tfo" },
 135         { TCPOPT_EXPERIMENT2, "exp" },
 136         { 0, NULL }
 137 };
 138
 139 static int
 140 tcp_cksum(netdissect_options *ndo,
 141           register const struct ip *ip,
 142           register const struct tcphdr *tp,
 143           register u_int len)
 144 {
 145         return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
 146                                 IPPROTO_TCP);
 147 }
 148
 149 static int
 150 tcp6_cksum(netdissect_options *ndo,
 151            register const struct ip6_hdr *ip6,
 152            register const struct tcphdr *tp,
 153            register u_int len)
 154 {
 155         return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
 156                                 IPPROTO_TCP);
 157 }
 158
 159 void
 160 tcp_print(netdissect_options *ndo,
 161           register const u_char *bp, register u_int length,
 162           register const u_char *bp2, int fragmented)
 163 {
 164         register const struct tcphdr *tp;
 165         register const struct ip *ip;
 166         register u_char flags;
 167         register u_int hlen;
 168         register char ch;
 169         uint16_t sport, dport, win, urp;
 170         uint32_t seq, ack, thseq, thack;
 171         u_int utoval;
 172         uint16_t magic;
 173         register int rev;
 174         register const struct ip6_hdr *ip6;
 175
 176         tp = (const struct tcphdr *)bp;
 177         ip = (const struct ip *)bp2;
 178         if (IP_V(ip) == 6)
 179                 ip6 = (const struct ip6_hdr *)bp2;
 180         else
 181                 ip6 = NULL;
 182         ch = '\0';
 183         if (!ND_TTEST(tp->th_dport)) {
 184                 ND_PRINT((ndo, "%s > %s: [|tcp]",
 185                              ipaddr_string(ndo, &ip->ip_src),
 186                              ipaddr_string(ndo, &ip->ip_dst)));
 187                 return;
 188         }
 189
 190         sport = EXTRACT_16BITS(&tp->th_sport);
 191         dport = EXTRACT_16BITS(&tp->th_dport);
 192
 193         hlen = TH_OFF(tp) * 4;
 194
 195         if (ip6) {
 196                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 197                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 198                                      ip6addr_string(ndo, &ip6->ip6_src),
 199                                      tcpport_string(ndo, sport),
 200                                      ip6addr_string(ndo, &ip6->ip6_dst),
 201                                      tcpport_string(ndo, dport)));
 202                 } else {
 203                         ND_PRINT((ndo, "%s > %s: ",
 204                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 205                 }
 206         } else {
 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(ndo, sport),
 211                                      ipaddr_string(ndo, &ip->ip_dst),
 212                                      tcpport_string(ndo, dport)));
 213                 } else {
 214                         ND_PRINT((ndo, "%s > %s: ",
 215                                      tcpport_string(ndo, sport), tcpport_string(ndo, 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                 if (ip6) {
 253                         register struct tcp_seq_hash6 *th;
 254                         struct tcp_seq_hash6 *tcp_seq_hash;
 255                         const struct in6_addr *src, *dst;
 256                         struct tha6 tha;
 257
 258                         tcp_seq_hash = tcp_seq_hash6;
 259                         src = &ip6->ip6_src;
 260                         dst = &ip6->ip6_dst;
 261                         if (sport > dport)
 262                                 rev = 1;
 263                         else if (sport == dport) {
 264                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
 265                                         rev = 1;
 266                         }
 267                         if (rev) {
 268                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
 269                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
 270                                 tha.port = dport << 16 | sport;
 271                         } else {
 272                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
 273                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
 274                                 tha.port = sport << 16 | dport;
 275                         }
 276
 277                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 278                              th->nxt; th = th->nxt)
 279                                 if (memcmp((char *)&tha, (char *)&th->addr,
 280                                            sizeof(th->addr)) == 0)
 281                                         break;
 282
 283                         if (!th->nxt || (flags & TH_SYN)) {
 284                                 /* didn't find it or new conversation */
 285                                 if (th->nxt == NULL) {
 286                                         th->nxt = (struct tcp_seq_hash6 *)
 287                                                 calloc(1, sizeof(*th));
 288                                         if (th->nxt == NULL)
 289                                                 (*ndo->ndo_error)(ndo,
 290                                                                   "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                         register struct tcp_seq_hash *th;
 308                         struct tcp_seq_hash *tcp_seq_hash;
 309                         struct tha tha;
 310
 311                         tcp_seq_hash = tcp_seq_hash4;
 312                         if (sport > dport)
 313                                 rev = 1;
 314                         else if (sport == dport) {
 315                                 if (UNALIGNED_MEMCMP(&ip->ip_src, &ip->ip_dst, sizeof ip->ip_dst) > 0)
 316                                         rev = 1;
 317                         }
 318                         if (rev) {
 319                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_dst, sizeof ip->ip_dst);
 320                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_src, sizeof ip->ip_src);
 321                                 tha.port = dport << 16 | sport;
 322                         } else {
 323                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_dst, sizeof ip->ip_dst);
 324                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_src, sizeof ip->ip_src);
 325                                 tha.port = sport << 16 | dport;
 326                         }
 327
 328                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 329                              th->nxt; th = th->nxt)
 330                                 if (memcmp((char *)&tha, (char *)&th->addr,
 331                                            sizeof(th->addr)) == 0)
 332                                         break;
 333
 334                         if (!th->nxt || (flags & TH_SYN)) {
 335                                 /* didn't find it or new conversation */
 336                                 if (th->nxt == NULL) {
 337                                         th->nxt = (struct tcp_seq_hash *)
 338                                                 calloc(1, sizeof(*th));
 339                                         if (th->nxt == NULL)
 340                                                 (*ndo->ndo_error)(ndo,
 341                                                                   "tcp_print: calloc");
 342                                 }
 343                                 th->addr = tha;
 344                                 if (rev)
 345                                         th->ack = seq, th->seq = ack - 1;
 346                                 else
 347                                         th->seq = seq, th->ack = ack - 1;
 348                         } else {
 349                                 if (rev)
 350                                         seq -= th->ack, ack -= th->seq;
 351                                 else
 352                                         seq -= th->seq, ack -= th->ack;
 353                         }
 354
 355                         thseq = th->seq;
 356                         thack = th->ack;
 357                 }
 358         } else {
 359                 /*fool gcc*/
 360                 thseq = thack = rev = 0;
 361         }
 362         if (hlen > length) {
 363                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
 364                              hlen, length));
 365                 return;
 366         }
 367
 368         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
 369                 /* Check the checksum, if possible. */
 370                 uint16_t sum, tcp_sum;
 371
 372                 if (IP_V(ip) == 4) {
 373                         if (ND_TTEST2(tp->th_sport, length)) {
 374                                 sum = tcp_cksum(ndo, ip, tp, length);
 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                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
 385                         if (ND_TTEST2(tp->th_sport, length)) {
 386                                 sum = tcp6_cksum(ndo, ip6, tp, length);
 387                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
 388
 389                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
 390                                 if (sum != 0)
 391                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
 392                                             in_cksum_shouldbe(tcp_sum, sum)));
 393                                 else
 394                                         ND_PRINT((ndo, " (correct)"));
 395
 396                         }
 397                 }
 398         }
 399
 400         length -= hlen;
 401         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
 402                 ND_PRINT((ndo, ", seq %u", seq));
 403
 404                 if (length > 0) {
 405                         ND_PRINT((ndo, ":%u", seq + length));
 406                 }
 407         }
 408
 409         if (flags & TH_ACK) {
 410                 ND_PRINT((ndo, ", ack %u", ack));
 411         }
 412
 413         ND_PRINT((ndo, ", win %d", win));
 414
 415         if (flags & TH_URG)
 416                 ND_PRINT((ndo, ", urg %d", urp));
 417         /*
 418          * Handle any options.
 419          */
 420         if (hlen > sizeof(*tp)) {
 421                 register const u_char *cp;
 422                 register u_int i, opt, datalen;
 423                 register u_int len;
 424
 425                 hlen -= sizeof(*tp);
 426                 cp = (const u_char *)tp + sizeof(*tp);
 427                 ND_PRINT((ndo, ", options ["));
 428                 while (hlen > 0) {
 429                         if (ch != '\0')
 430                                 ND_PRINT((ndo, "%c", ch));
 431                         ND_TCHECK(*cp);
 432                         opt = *cp++;
 433                         if (ZEROLENOPT(opt))
 434                                 len = 1;
 435                         else {
 436                                 ND_TCHECK(*cp);
 437                                 len = *cp++;    /* total including type, len */
 438                                 if (len < 2 || len > hlen)
 439                                         goto bad;
 440                                 --hlen;         /* account for length byte */
 441                         }
 442                         --hlen;                 /* account for type byte */
 443                         datalen = 0;
 444
 445 /* Bail if "l" bytes of data are not left or were not captured  */
 446 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 447
 448
 449                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 450
 451                         switch (opt) {
 452
 453                         case TCPOPT_MAXSEG:
 454                                 datalen = 2;
 455                                 LENCHECK(datalen);
 456                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
 457                                 break;
 458
 459                         case TCPOPT_WSCALE:
 460                                 datalen = 1;
 461                                 LENCHECK(datalen);
 462                                 ND_PRINT((ndo, " %u", *cp));
 463                                 break;
 464
 465                         case TCPOPT_SACK:
 466                                 datalen = len - 2;
 467                                 if (datalen % 8 != 0) {
 468                                         ND_PRINT((ndo, " invalid sack"));
 469                                 } else {
 470                                         uint32_t s, e;
 471
 472                                         ND_PRINT((ndo, " %d ", datalen / 8));
 473                                         for (i = 0; i < datalen; i += 8) {
 474                                                 LENCHECK(i + 4);
 475                                                 s = EXTRACT_32BITS(cp + i);
 476                                                 LENCHECK(i + 8);
 477                                                 e = EXTRACT_32BITS(cp + i + 4);
 478                                                 if (rev) {
 479                                                         s -= thseq;
 480                                                         e -= thseq;
 481                                                 } else {
 482                                                         s -= thack;
 483                                                         e -= thack;
 484                                                 }
 485                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 486                                         }
 487                                 }
 488                                 break;
 489
 490                         case TCPOPT_CC:
 491                         case TCPOPT_CCNEW:
 492                         case TCPOPT_CCECHO:
 493                         case TCPOPT_ECHO:
 494                         case TCPOPT_ECHOREPLY:
 495
 496                                 /*
 497                                  * those options share their semantics.
 498                                  * fall through
 499                                  */
 500                                 datalen = 4;
 501                                 LENCHECK(datalen);
 502                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
 503                                 break;
 504
 505                         case TCPOPT_TIMESTAMP:
 506                                 datalen = 8;
 507                                 LENCHECK(datalen);
 508                                 ND_PRINT((ndo, " val %u ecr %u",
 509                                              EXTRACT_32BITS(cp),
 510                                              EXTRACT_32BITS(cp + 4)));
 511                                 break;
 512
 513                         case TCPOPT_SIGNATURE:
 514                                 datalen = TCP_SIGLEN;
 515                                 LENCHECK(datalen);
 516                                 ND_PRINT((ndo, " "));
 517 #ifdef HAVE_LIBCRYPTO
 518                                 switch (tcp_verify_signature(ndo, ip, tp,
 519                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 520
 521                                 case SIGNATURE_VALID:
 522                                         ND_PRINT((ndo, "valid"));
 523                                         break;
 524
 525                                 case SIGNATURE_INVALID:
 526                                         ND_PRINT((ndo, "invalid"));
 527                                         break;
 528
 529                                 case CANT_CHECK_SIGNATURE:
 530                                         ND_PRINT((ndo, "can't check - "));
 531                                         for (i = 0; i < TCP_SIGLEN; ++i)
 532                                                 ND_PRINT((ndo, "%02x", cp[i]));
 533                                         break;
 534                                 }
 535 #else
 536                                 for (i = 0; i < TCP_SIGLEN; ++i)
 537                                         ND_PRINT((ndo, "%02x", cp[i]));
 538 #endif
 539                                 break;
 540
 541                         case TCPOPT_SCPS:
 542                                 datalen = 2;
 543                                 LENCHECK(datalen);
 544                                 ND_PRINT((ndo, " cap %02x id %u", cp[0], cp[1]));
 545                                 break;
 546
 547                         case TCPOPT_AUTH:
 548                                 ND_PRINT((ndo, " keyid %d", *cp++));
 549                                 datalen = len - 3;
 550                                 for (i = 0; i < datalen; ++i) {
 551                                         LENCHECK(i);
 552                                         ND_PRINT((ndo, "%02x", cp[i]));
 553                                 }
 554                                 break;
 555
 556
 557                         case TCPOPT_EOL:
 558                         case TCPOPT_NOP:
 559                         case TCPOPT_SACKOK:
 560                                 /*
 561                                  * Nothing interesting.
 562                                  * fall through
 563                                  */
 564                                 break;
 565
 566                         case TCPOPT_UTO:
 567                                 datalen = 2;
 568                                 LENCHECK(datalen);
 569                                 utoval = EXTRACT_16BITS(cp);
 570                                 ND_PRINT((ndo, " 0x%x", utoval));
 571                                 if (utoval & 0x0001)
 572                                         utoval = (utoval >> 1) * 60;
 573                                 else
 574                                         utoval >>= 1;
 575                                 ND_PRINT((ndo, " %u", utoval));
 576                                 break;
 577
 578                         case TCPOPT_MPTCP:
 579                                 datalen = len - 2;
 580                                 LENCHECK(datalen);
 581                                 if (!mptcp_print(ndo, cp-2, len, flags))
 582                                         goto bad;
 583                                 break;
 584
 585                         case TCPOPT_FASTOPEN:
 586                                 datalen = len - 2;
 587                                 LENCHECK(datalen);
 588                                 ND_PRINT((ndo, " "));
 589                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 590                                 break;
 591
 592                         case TCPOPT_EXPERIMENT2:
 593                                 datalen = len - 2;
 594                                 LENCHECK(datalen);
 595                                 if (datalen < 2)
 596                                         goto bad;
 597                                 /* RFC6994 */
 598                                 magic = EXTRACT_16BITS(cp);
 599                                 ND_PRINT((ndo, "-"));
 600
 601                                 switch(magic) {
 602
 603                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 604                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 605                                         break;
 606
 607                                 default:
 608                                         /* Unknown magic number */
 609                                         ND_PRINT((ndo, "%04x", magic));
 610                                         break;
 611                                 }
 612                                 break;
 613
 614                         default:
 615                                 datalen = len - 2;
 616                                 if (datalen)
 617                                         ND_PRINT((ndo, " 0x"));
 618                                 for (i = 0; i < datalen; ++i) {
 619                                         LENCHECK(i);
 620                                         ND_PRINT((ndo, "%02x", cp[i]));
 621                                 }
 622                                 break;
 623                         }
 624
 625                         /* Account for data printed */
 626                         cp += datalen;
 627                         hlen -= datalen;
 628
 629                         /* Check specification against observed length */
 630                         ++datalen;                      /* option octet */
 631                         if (!ZEROLENOPT(opt))
 632                                 ++datalen;              /* size octet */
 633                         if (datalen != len)
 634                                 ND_PRINT((ndo, "[len %d]", len));
 635                         ch = ',';
 636                         if (opt == TCPOPT_EOL)
 637                                 break;
 638                 }
 639                 ND_PRINT((ndo, "]"));
 640         }
 641
 642         /*
 643          * Print length field before crawling down the stack.
 644          */
 645         ND_PRINT((ndo, ", length %u", length));
 646
 647         if (length <= 0)
 648                 return;
 649
 650         /*
 651          * Decode payload if necessary.
 652          */
 653         bp += TH_OFF(tp) * 4;
 654         if ((flags & TH_RST) && ndo->ndo_vflag) {
 655                 print_tcp_rst_data(ndo, bp, length);
 656                 return;
 657         }
 658
 659         if (ndo->ndo_packettype) {
 660                 switch (ndo->ndo_packettype) {
 661                 case PT_ZMTP1:
 662                         zmtp1_print(ndo, bp, length);
 663                         break;
 664                 case PT_RESP:
 665                         resp_print(ndo, bp, length);
 666                         break;
 667                 }
 668                 return;
 669         }
 670
 671         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 672                 telnet_print(ndo, bp, length);
 673         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 674                 ND_PRINT((ndo, ": "));
 675                 smtp_print(ndo, bp, length);
 676         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 677                 bgp_print(ndo, bp, length);
 678         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 679                 pptp_print(ndo, bp);
 680         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 681                 resp_print(ndo, bp, length);
 682 #ifdef ENABLE_SMB
 683         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 684                 nbt_tcp_print(ndo, bp, length);
 685         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 686                 smb_tcp_print(ndo, bp, length);
 687 #endif
 688         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 689                 beep_print(ndo, bp, length);
 690         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 691                 openflow_print(ndo, bp, length);
 692         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 693                 ND_PRINT((ndo, ": "));
 694                 ftp_print(ndo, bp, length);
 695         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 696                 ND_PRINT((ndo, ": "));
 697                 http_print(ndo, bp, length);
 698         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 699                 ND_PRINT((ndo, ": "));
 700                 rtsp_print(ndo, bp, length);
 701         } else if (length > 2 &&
 702                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 703                 /*
 704                  * TCP DNS query has 2byte length at the head.
 705                  * XXX packet could be unaligned, it can go strange
 706                  */
 707                 ns_print(ndo, bp + 2, length - 2, 0);
 708         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 709                 msdp_print(ndo, bp, length);
 710         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 711                 rpki_rtr_print(ndo, bp, length);
 712         }
 713         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 714                 ldp_print(ndo, bp, length);
 715         }
 716         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 717                  length >= 4 && ND_TTEST2(*bp, 4)) {
 718                 /*
 719                  * If data present, header length valid, and NFS port used,
 720                  * assume NFS.
 721                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 722                  * to NFS print routines.
 723                  */
 724                 uint32_t fraglen;
 725                 register const struct sunrpc_msg *rp;
 726                 enum sunrpc_msg_type direction;
 727
 728                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
 729                 if (fraglen > (length) - 4)
 730                         fraglen = (length) - 4;
 731                 rp = (const struct sunrpc_msg *)(bp + 4);
 732                 if (ND_TTEST(rp->rm_direction)) {
 733                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
 734                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 735                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 736                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 737                                 return;
 738                         }
 739                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 740                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
 741                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 742                                 return;
 743                         }
 744                 }
 745         }
 746
 747         return;
 748  bad:
 749         ND_PRINT((ndo, "[bad opt]"));
 750         if (ch != '\0')
 751                 ND_PRINT((ndo, ">"));
 752         return;
 753  trunc:
 754         ND_PRINT((ndo, "[|tcp]"));
 755         if (ch != '\0')
 756                 ND_PRINT((ndo, ">"));
 757 }
 758
 759 /*
 760  * RFC1122 says the following on data in RST segments:
 761  *
 762  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 763  *
 764  *            A TCP SHOULD allow a received RST segment to include data.
 765  *
 766  *            DISCUSSION
 767  *                 It has been suggested that a RST segment could contain
 768  *                 ASCII text that encoded and explained the cause of the
 769  *                 RST.  No standard has yet been established for such
 770  *                 data.
 771  *
 772  */
 773
 774 static void
 775 print_tcp_rst_data(netdissect_options *ndo,
 776                    register const u_char *sp, u_int length)
 777 {
 778         int c;
 779
 780         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 781         if (length > MAX_RST_DATA_LEN) {
 782                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 783                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 784         }
 785         ND_PRINT((ndo, " "));
 786         while (length-- && sp < ndo->ndo_snapend) {
 787                 c = *sp++;
 788                 safeputchar(ndo, c);
 789         }
 790         ND_PRINT((ndo, "]"));
 791 }
 792
 793 static void
 794 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 795                           u_int datalen, int exp)
 796 {
 797         u_int i;
 798
 799         if (exp)
 800                 ND_PRINT((ndo, "tfo"));
 801
 802         if (datalen == 0) {
 803                 /* Fast Open Cookie Request */
 804                 ND_PRINT((ndo, " cookiereq"));
 805         } else {
 806                 /* Fast Open Cookie */
 807                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 808                         ND_PRINT((ndo, " invalid"));
 809                 } else {
 810                         ND_PRINT((ndo, " cookie "));
 811                         for (i = 0; i < datalen; ++i)
 812                                 ND_PRINT((ndo, "%02x", cp[i]));
 813                 }
 814         }
 815 }
 816
 817 #ifdef HAVE_LIBCRYPTO
 818 USES_APPLE_DEPRECATED_API
 819 static int
 820 tcp_verify_signature(netdissect_options *ndo,
 821                      const struct ip *ip, const struct tcphdr *tp,
 822                      const u_char *data, int length, const u_char *rcvsig)
 823 {
 824         struct tcphdr tp1;
 825         u_char sig[TCP_SIGLEN];
 826         char zero_proto = 0;
 827         MD5_CTX ctx;
 828         uint16_t savecsum, tlen;
 829         const struct ip6_hdr *ip6;
 830         uint32_t len32;
 831         uint8_t nxt;
 832
 833         if (data + length > ndo->ndo_snapend) {
 834                 ND_PRINT((ndo, "snaplen too short, "));
 835                 return (CANT_CHECK_SIGNATURE);
 836         }
 837
 838         tp1 = *tp;
 839
 840         if (ndo->ndo_sigsecret == NULL) {
 841                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 842                 return (CANT_CHECK_SIGNATURE);
 843         }
 844
 845         MD5_Init(&ctx);
 846         /*
 847          * Step 1: Update MD5 hash with IP pseudo-header.
 848          */
 849         if (IP_V(ip) == 4) {
 850                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 851                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 852                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 853                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 854                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
 855                 tlen = htons(tlen);
 856                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 857         } else if (IP_V(ip) == 6) {
 858                 ip6 = (const struct ip6_hdr *)ip;
 859                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 860                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 861                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
 862                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 863                 nxt = 0;
 864                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 865                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 866                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 867                 nxt = IPPROTO_TCP;
 868                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 869         } else {
 870                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 871                 return (CANT_CHECK_SIGNATURE);
 872         }
 873
 874         /*
 875          * Step 2: Update MD5 hash with TCP header, excluding options.
 876          * The TCP checksum must be set to zero.
 877          */
 878         savecsum = tp1.th_sum;
 879         tp1.th_sum = 0;
 880         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 881         tp1.th_sum = savecsum;
 882         /*
 883          * Step 3: Update MD5 hash with TCP segment data, if present.
 884          */
 885         if (length > 0)
 886                 MD5_Update(&ctx, data, length);
 887         /*
 888          * Step 4: Update MD5 hash with shared secret.
 889          */
 890         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 891         MD5_Final(sig, &ctx);
 892
 893         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 894                 return (SIGNATURE_VALID);
 895         else
 896                 return (SIGNATURE_INVALID);
 897 }
 898 USES_APPLE_RST
 899 #endif /* HAVE_LIBCRYPTO */
 900
 901 /*
 902  * Local Variables:
 903  * c-style: whitesmith
 904  * c-basic-offset: 8
 905  * End:
 906  */