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         uint32_t seq;
  80         uint32_t 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         uint32_t seq;
  93         uint32_t 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_TCPAO, "tcp-ao" },
 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_BE_U_2(&tp->th_sport);
 191         dport = EXTRACT_BE_U_2(&tp->th_dport);
 192
 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(ndo, sport),
 198                                      ip6addr_string(ndo, &ip6->ip6_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         } else {
 205                 if (EXTRACT_U_1(ip->ip_p) == IPPROTO_TCP) {
 206                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
 207                                      ipaddr_string(ndo, &ip->ip_src),
 208                                      tcpport_string(ndo, sport),
 209                                      ipaddr_string(ndo, &ip->ip_dst),
 210                                      tcpport_string(ndo, dport)));
 211                 } else {
 212                         ND_PRINT((ndo, "%s > %s: ",
 213                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
 214                 }
 215         }
 216
 217         ND_TCHECK(*tp);
 218
 219         hlen = TH_OFF(tp) * 4;
 220
 221         if (hlen < sizeof(*tp)) {
 222                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
 223                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
 224                 return;
 225         }
 226
 227         seq = EXTRACT_BE_U_4(&tp->th_seq);
 228         ack = EXTRACT_BE_U_4(&tp->th_ack);
 229         win = EXTRACT_BE_U_2(&tp->th_win);
 230         urp = EXTRACT_BE_U_2(&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 = EXTRACT_U_1(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 void *src, *dst;
 256                         struct tha6 tha;
 257
 258                         tcp_seq_hash = tcp_seq_hash6;
 259                         src = (const void *)&ip6->ip6_src;
 260                         dst = (const void *)&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_BE_U_2(&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_BE_U_2(&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_1(cp);
 432                         opt = EXTRACT_U_1(cp);
 433                         cp++;
 434                         if (ZEROLENOPT(opt))
 435                                 len = 1;
 436                         else {
 437                                 ND_TCHECK_1(cp);
 438                                 len = EXTRACT_U_1(cp);
 439                                 cp++;   /* total including type, len */
 440                                 if (len < 2 || len > hlen)
 441                                         goto bad;
 442                                 --hlen;         /* account for length byte */
 443                         }
 444                         --hlen;                 /* account for type byte */
 445                         datalen = 0;
 446
 447 /* Bail if "l" bytes of data are not left or were not captured  */
 448 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
 449
 450
 451                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
 452
 453                         switch (opt) {
 454
 455                         case TCPOPT_MAXSEG:
 456                                 datalen = 2;
 457                                 LENCHECK(datalen);
 458                                 ND_PRINT((ndo, " %u", EXTRACT_BE_U_2(cp)));
 459                                 break;
 460
 461                         case TCPOPT_WSCALE:
 462                                 datalen = 1;
 463                                 LENCHECK(datalen);
 464                                 ND_PRINT((ndo, " %u", EXTRACT_U_1(cp)));
 465                                 break;
 466
 467                         case TCPOPT_SACK:
 468                                 datalen = len - 2;
 469                                 if (datalen % 8 != 0) {
 470                                         ND_PRINT((ndo, " invalid sack"));
 471                                 } else {
 472                                         uint32_t s, e;
 473
 474                                         ND_PRINT((ndo, " %d ", datalen / 8));
 475                                         for (i = 0; i < datalen; i += 8) {
 476                                                 LENCHECK(i + 4);
 477                                                 s = EXTRACT_BE_U_4(cp + i);
 478                                                 LENCHECK(i + 8);
 479                                                 e = EXTRACT_BE_U_4(cp + i + 4);
 480                                                 if (rev) {
 481                                                         s -= thseq;
 482                                                         e -= thseq;
 483                                                 } else {
 484                                                         s -= thack;
 485                                                         e -= thack;
 486                                                 }
 487                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
 488                                         }
 489                                 }
 490                                 break;
 491
 492                         case TCPOPT_CC:
 493                         case TCPOPT_CCNEW:
 494                         case TCPOPT_CCECHO:
 495                         case TCPOPT_ECHO:
 496                         case TCPOPT_ECHOREPLY:
 497
 498                                 /*
 499                                  * those options share their semantics.
 500                                  * fall through
 501                                  */
 502                                 datalen = 4;
 503                                 LENCHECK(datalen);
 504                                 ND_PRINT((ndo, " %u", EXTRACT_BE_U_4(cp)));
 505                                 break;
 506
 507                         case TCPOPT_TIMESTAMP:
 508                                 datalen = 8;
 509                                 LENCHECK(datalen);
 510                                 ND_PRINT((ndo, " val %u ecr %u",
 511                                              EXTRACT_BE_U_4(cp),
 512                                              EXTRACT_BE_U_4(cp + 4)));
 513                                 break;
 514
 515                         case TCPOPT_SIGNATURE:
 516                                 datalen = TCP_SIGLEN;
 517                                 LENCHECK(datalen);
 518                                 ND_PRINT((ndo, " "));
 519 #ifdef HAVE_LIBCRYPTO
 520                                 switch (tcp_verify_signature(ndo, ip, tp,
 521                                                              bp + TH_OFF(tp) * 4, length, cp)) {
 522
 523                                 case SIGNATURE_VALID:
 524                                         ND_PRINT((ndo, "valid"));
 525                                         break;
 526
 527                                 case SIGNATURE_INVALID:
 528                                         ND_PRINT((ndo, "invalid"));
 529                                         break;
 530
 531                                 case CANT_CHECK_SIGNATURE:
 532                                         ND_PRINT((ndo, "can't check - "));
 533                                         for (i = 0; i < TCP_SIGLEN; ++i)
 534                                                 ND_PRINT((ndo, "%02x", EXTRACT_U_1(cp + i)));
 535                                         break;
 536                                 }
 537 #else
 538                                 for (i = 0; i < TCP_SIGLEN; ++i)
 539                                         ND_PRINT((ndo, "%02x", EXTRACT_U_1(cp + i)));
 540 #endif
 541                                 break;
 542
 543                         case TCPOPT_SCPS:
 544                                 datalen = 2;
 545                                 LENCHECK(datalen);
 546                                 ND_PRINT((ndo, " cap %02x id %u", EXTRACT_U_1(cp), EXTRACT_U_1(cp + 1)));
 547                                 break;
 548
 549                         case TCPOPT_TCPAO:
 550                                 datalen = len - 2;
 551                                 /* RFC 5925 Section 2.2:
 552                                  * "The Length value MUST be greater than or equal to 4."
 553                                  * (This includes the Kind and Length fields already processed
 554                                  * at this point.)
 555                                  */
 556                                 if (datalen < 2) {
 557                                         ND_PRINT((ndo, " invalid"));
 558                                 } else {
 559                                         LENCHECK(1);
 560                                         ND_PRINT((ndo, " keyid %u", EXTRACT_U_1(cp)));
 561                                         LENCHECK(2);
 562                                         ND_PRINT((ndo, " rnextkeyid %u", EXTRACT_U_1(cp + 1)));
 563                                         if (datalen > 2) {
 564                                                 ND_PRINT((ndo, " mac 0x"));
 565                                                 for (i = 2; i < datalen; i++) {
 566                                                         LENCHECK(i + 1);
 567                                                         ND_PRINT((ndo, "%02x", EXTRACT_U_1(cp + i)));
 568                                                 }
 569                                         }
 570                                 }
 571                                 break;
 572
 573                         case TCPOPT_EOL:
 574                         case TCPOPT_NOP:
 575                         case TCPOPT_SACKOK:
 576                                 /*
 577                                  * Nothing interesting.
 578                                  * fall through
 579                                  */
 580                                 break;
 581
 582                         case TCPOPT_UTO:
 583                                 datalen = 2;
 584                                 LENCHECK(datalen);
 585                                 utoval = EXTRACT_BE_U_2(cp);
 586                                 ND_PRINT((ndo, " 0x%x", utoval));
 587                                 if (utoval & 0x0001)
 588                                         utoval = (utoval >> 1) * 60;
 589                                 else
 590                                         utoval >>= 1;
 591                                 ND_PRINT((ndo, " %u", utoval));
 592                                 break;
 593
 594                         case TCPOPT_MPTCP:
 595                                 datalen = len - 2;
 596                                 LENCHECK(datalen);
 597                                 if (!mptcp_print(ndo, cp-2, len, flags))
 598                                         goto bad;
 599                                 break;
 600
 601                         case TCPOPT_FASTOPEN:
 602                                 datalen = len - 2;
 603                                 LENCHECK(datalen);
 604                                 ND_PRINT((ndo, " "));
 605                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
 606                                 break;
 607
 608                         case TCPOPT_EXPERIMENT2:
 609                                 datalen = len - 2;
 610                                 LENCHECK(datalen);
 611                                 if (datalen < 2)
 612                                         goto bad;
 613                                 /* RFC6994 */
 614                                 magic = EXTRACT_BE_U_2(cp);
 615                                 ND_PRINT((ndo, "-"));
 616
 617                                 switch(magic) {
 618
 619                                 case 0xf989: /* TCP Fast Open RFC 7413 */
 620                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
 621                                         break;
 622
 623                                 default:
 624                                         /* Unknown magic number */
 625                                         ND_PRINT((ndo, "%04x", magic));
 626                                         break;
 627                                 }
 628                                 break;
 629
 630                         default:
 631                                 datalen = len - 2;
 632                                 if (datalen)
 633                                         ND_PRINT((ndo, " 0x"));
 634                                 for (i = 0; i < datalen; ++i) {
 635                                         LENCHECK(i + 1);
 636                                         ND_PRINT((ndo, "%02x", EXTRACT_U_1(cp + i)));
 637                                 }
 638                                 break;
 639                         }
 640
 641                         /* Account for data printed */
 642                         cp += datalen;
 643                         hlen -= datalen;
 644
 645                         /* Check specification against observed length */
 646                         ++datalen;                      /* option octet */
 647                         if (!ZEROLENOPT(opt))
 648                                 ++datalen;              /* size octet */
 649                         if (datalen != len)
 650                                 ND_PRINT((ndo, "[len %d]", len));
 651                         ch = ',';
 652                         if (opt == TCPOPT_EOL)
 653                                 break;
 654                 }
 655                 ND_PRINT((ndo, "]"));
 656         }
 657
 658         /*
 659          * Print length field before crawling down the stack.
 660          */
 661         ND_PRINT((ndo, ", length %u", length));
 662
 663         if (length <= 0)
 664                 return;
 665
 666         /*
 667          * Decode payload if necessary.
 668          */
 669         bp += TH_OFF(tp) * 4;
 670         if ((flags & TH_RST) && ndo->ndo_vflag) {
 671                 print_tcp_rst_data(ndo, bp, length);
 672                 return;
 673         }
 674
 675         if (ndo->ndo_packettype) {
 676                 switch (ndo->ndo_packettype) {
 677                 case PT_ZMTP1:
 678                         zmtp1_print(ndo, bp, length);
 679                         break;
 680                 case PT_RESP:
 681                         resp_print(ndo, bp, length);
 682                         break;
 683                 }
 684                 return;
 685         }
 686
 687         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
 688                 telnet_print(ndo, bp, length);
 689         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
 690                 ND_PRINT((ndo, ": "));
 691                 smtp_print(ndo, bp, length);
 692         } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
 693                 ND_PRINT((ndo, ": "));
 694                 txtproto_print(ndo, bp, length, "whois", NULL, 0); /* RFC 3912 */
 695         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
 696                 bgp_print(ndo, bp, length);
 697         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
 698                 pptp_print(ndo, bp);
 699         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
 700                 resp_print(ndo, bp, length);
 701 #ifdef ENABLE_SMB
 702         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
 703                 nbt_tcp_print(ndo, bp, length);
 704         else if (IS_SRC_OR_DST_PORT(SMB_PORT))
 705                 smb_tcp_print(ndo, bp, length);
 706 #endif
 707         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
 708                 beep_print(ndo, bp, length);
 709         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
 710                 openflow_print(ndo, bp, length);
 711         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
 712                 ND_PRINT((ndo, ": "));
 713                 ftp_print(ndo, bp, length);
 714         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
 715                 ND_PRINT((ndo, ": "));
 716                 http_print(ndo, bp, length);
 717         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
 718                 ND_PRINT((ndo, ": "));
 719                 rtsp_print(ndo, bp, length);
 720         } else if (length > 2 &&
 721                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
 722                 /*
 723                  * TCP DNS query has 2byte length at the head.
 724                  * XXX packet could be unaligned, it can go strange
 725                  */
 726                 domain_print(ndo, bp + 2, length - 2, 0);
 727         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
 728                 msdp_print(ndo, bp, length);
 729         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
 730                 rpki_rtr_print(ndo, bp, length);
 731         }
 732         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
 733                 ldp_print(ndo, bp, length);
 734         }
 735         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
 736                  length >= 4 && ND_TTEST_4(bp)) {
 737                 /*
 738                  * If data present, header length valid, and NFS port used,
 739                  * assume NFS.
 740                  * Pass offset of data plus 4 bytes for RPC TCP msg length
 741                  * to NFS print routines.
 742                  */
 743                 uint32_t fraglen;
 744                 register const struct sunrpc_msg *rp;
 745                 enum sunrpc_msg_type direction;
 746
 747                 fraglen = EXTRACT_BE_U_4(bp) & 0x7FFFFFFF;
 748                 if (fraglen > (length) - 4)
 749                         fraglen = (length) - 4;
 750                 rp = (const struct sunrpc_msg *)(bp + 4);
 751                 if (ND_TTEST(rp->rm_direction)) {
 752                         direction = (enum sunrpc_msg_type) EXTRACT_BE_U_4(&rp->rm_direction);
 753                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
 754                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_BE_U_4(&rp->rm_xid)));
 755                                 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 756                                 return;
 757                         }
 758                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
 759                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_BE_U_4(&rp->rm_xid)));
 760                                 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
 761                                 return;
 762                         }
 763                 }
 764         }
 765
 766         return;
 767  bad:
 768         ND_PRINT((ndo, "[bad opt]"));
 769         if (ch != '\0')
 770                 ND_PRINT((ndo, ">"));
 771         return;
 772  trunc:
 773         ND_PRINT((ndo, "[|tcp]"));
 774         if (ch != '\0')
 775                 ND_PRINT((ndo, ">"));
 776 }
 777
 778 /*
 779  * RFC1122 says the following on data in RST segments:
 780  *
 781  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
 782  *
 783  *            A TCP SHOULD allow a received RST segment to include data.
 784  *
 785  *            DISCUSSION
 786  *                 It has been suggested that a RST segment could contain
 787  *                 ASCII text that encoded and explained the cause of the
 788  *                 RST.  No standard has yet been established for such
 789  *                 data.
 790  *
 791  */
 792
 793 static void
 794 print_tcp_rst_data(netdissect_options *ndo,
 795                    register const u_char *sp, u_int length)
 796 {
 797         int c;
 798
 799         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
 800         if (length > MAX_RST_DATA_LEN) {
 801                 length = MAX_RST_DATA_LEN;      /* can use -X for longer */
 802                 ND_PRINT((ndo, "+"));                   /* indicate we truncate */
 803         }
 804         ND_PRINT((ndo, " "));
 805         while (length-- && sp < ndo->ndo_snapend) {
 806                 c = EXTRACT_U_1(sp);
 807                 sp++;
 808                 safeputchar(ndo, c);
 809         }
 810         ND_PRINT((ndo, "]"));
 811 }
 812
 813 static void
 814 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
 815                           u_int datalen, int exp)
 816 {
 817         u_int i;
 818
 819         if (exp)
 820                 ND_PRINT((ndo, "tfo"));
 821
 822         if (datalen == 0) {
 823                 /* Fast Open Cookie Request */
 824                 ND_PRINT((ndo, " cookiereq"));
 825         } else {
 826                 /* Fast Open Cookie */
 827                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
 828                         ND_PRINT((ndo, " invalid"));
 829                 } else {
 830                         ND_PRINT((ndo, " cookie "));
 831                         for (i = 0; i < datalen; ++i)
 832                                 ND_PRINT((ndo, "%02x", EXTRACT_U_1(cp + i)));
 833                 }
 834         }
 835 }
 836
 837 #ifdef HAVE_LIBCRYPTO
 838 USES_APPLE_DEPRECATED_API
 839 static int
 840 tcp_verify_signature(netdissect_options *ndo,
 841                      const struct ip *ip, const struct tcphdr *tp,
 842                      const u_char *data, int length, const u_char *rcvsig)
 843 {
 844         struct tcphdr tp1;
 845         u_char sig[TCP_SIGLEN];
 846         char zero_proto = 0;
 847         MD5_CTX ctx;
 848         uint16_t savecsum, tlen;
 849         const struct ip6_hdr *ip6;
 850         uint32_t len32;
 851         uint8_t nxt;
 852
 853         if (data + length > ndo->ndo_snapend) {
 854                 ND_PRINT((ndo, "snaplen too short, "));
 855                 return (CANT_CHECK_SIGNATURE);
 856         }
 857
 858         tp1 = *tp;
 859
 860         if (ndo->ndo_sigsecret == NULL) {
 861                 ND_PRINT((ndo, "shared secret not supplied with -M, "));
 862                 return (CANT_CHECK_SIGNATURE);
 863         }
 864
 865         MD5_Init(&ctx);
 866         /*
 867          * Step 1: Update MD5 hash with IP pseudo-header.
 868          */
 869         if (IP_V(ip) == 4) {
 870                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
 871                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
 872                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
 873                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
 874                 tlen = EXTRACT_BE_U_2(&ip->ip_len) - IP_HL(ip) * 4;
 875                 tlen = htons(tlen);
 876                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
 877         } else if (IP_V(ip) == 6) {
 878                 ip6 = (const struct ip6_hdr *)ip;
 879                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
 880                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
 881                 len32 = htonl(EXTRACT_BE_U_2(&ip6->ip6_plen));
 882                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
 883                 nxt = 0;
 884                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 885                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 886                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 887                 nxt = IPPROTO_TCP;
 888                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
 889         } else {
 890                 ND_PRINT((ndo, "IP version not 4 or 6, "));
 891                 return (CANT_CHECK_SIGNATURE);
 892         }
 893
 894         /*
 895          * Step 2: Update MD5 hash with TCP header, excluding options.
 896          * The TCP checksum must be set to zero.
 897          */
 898         savecsum = tp1.th_sum;
 899         tp1.th_sum = 0;
 900         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
 901         tp1.th_sum = savecsum;
 902         /*
 903          * Step 3: Update MD5 hash with TCP segment data, if present.
 904          */
 905         if (length > 0)
 906                 MD5_Update(&ctx, data, length);
 907         /*
 908          * Step 4: Update MD5 hash with shared secret.
 909          */
 910         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
 911         MD5_Final(sig, &ctx);
 912
 913         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
 914                 return (SIGNATURE_VALID);
 915         else
 916                 return (SIGNATURE_INVALID);
 917 }
 918 USES_APPLE_RST
 919 #endif /* HAVE_LIBCRYPTO */
 920
 921 /*
 922  * Local Variables:
 923  * c-style: whitesmith
 924  * c-basic-offset: 8
 925  * End:
 926  */