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

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