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

   1 /*
   2  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code distributions
   7  * retain the above copyright notice and this paragraph in its entirety, (2)
   8  * distributions including binary code include the above copyright notice and
   9  * this paragraph in its entirety in the documentation or other materials
  10  * provided with the distribution, and (3) all advertising materials mentioning
  11  * features or use of this software display the following acknowledgement:
  12  * ``This product includes software developed by the University of California,
  13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
  14  * the University nor the names of its contributors may be used to endorse
  15  * or promote products derived from this software without specific prior
  16  * written permission.
  17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
  18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
  19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  20  */
  21
  22 #ifndef lint
  23 static const char rcsid[] =
  24     "@(#) $Header: /tcpdump/master/tcpdump/print-tcp.c,v 1.68 2000-07-29 08:03:05 assar Exp $ (LBL)";
  25 #endif
  26
  27 #ifdef HAVE_CONFIG_H
  28 #include "config.h"
  29 #endif
  30
  31 #include <sys/param.h>
  32 #include <sys/time.h>
  33
  34 #include <rpc/rpc.h>
  35
  36 #include <netinet/in.h>
  37 #include <netinet/in_systm.h>
  38 #include <netinet/ip.h>
  39 #include <netinet/ip_var.h>
  40 #include <netinet/tcp.h>
  41
  42 #include <stdio.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46
  47 #ifdef INET6
  48 #include <netinet/ip6.h>
  49 #endif
  50
  51 #include "interface.h"
  52 #include "addrtoname.h"
  53 #include "extract.h"
  54
  55 /* Compatibility */
  56 #ifndef TCPOPT_WSCALE
  57 #define TCPOPT_WSCALE           3       /* window scale factor (rfc1072) */
  58 #endif
  59 #ifndef TCPOPT_SACKOK
  60 #define TCPOPT_SACKOK           4       /* selective ack ok (rfc1072) */
  61 #endif
  62 #ifndef TCPOPT_SACK
  63 #define TCPOPT_SACK             5       /* selective ack (rfc1072) */
  64 #endif
  65 #ifndef TCPOPT_ECHO
  66 #define TCPOPT_ECHO             6       /* echo (rfc1072) */
  67 #endif
  68 #ifndef TCPOPT_ECHOREPLY
  69 #define TCPOPT_ECHOREPLY        7       /* echo (rfc1072) */
  70 #endif
  71 #ifndef TCPOPT_TIMESTAMP
  72 #define TCPOPT_TIMESTAMP        8       /* timestamps (rfc1323) */
  73 #endif
  74 #ifndef TCPOPT_CC
  75 #define TCPOPT_CC               11      /* T/TCP CC options (rfc1644) */
  76 #endif
  77 #ifndef TCPOPT_CCNEW
  78 #define TCPOPT_CCNEW            12      /* T/TCP CC options (rfc1644) */
  79 #endif
  80 #ifndef TCPOPT_CCECHO
  81 #define TCPOPT_CCECHO           13      /* T/TCP CC options (rfc1644) */
  82 #endif
  83
  84 /*
  85  * Definitions required for ECN
  86  * for use if the OS running tcpdump does not have ECN
  87  */
  88 #ifndef TH_ECNECHO
  89 #define TH_ECNECHO              0x40    /* ECN Echo in tcp header */
  90 #endif
  91 #ifndef TH_CWR
  92 #define TH_CWR                  0x80    /* ECN Cwnd Reduced in tcp header*/
  93 #endif
  94
  95 struct tha {
  96 #ifndef INET6
  97         struct in_addr src;
  98         struct in_addr dst;
  99 #else
 100         struct in6_addr src;
 101         struct in6_addr dst;
 102 #endif /*INET6*/
 103         u_int port;
 104 };
 105
 106 struct tcp_seq_hash {
 107         struct tcp_seq_hash *nxt;
 108         struct tha addr;
 109         tcp_seq seq;
 110         tcp_seq ack;
 111 };
 112
 113 #define TSEQ_HASHSIZE 919
 114
 115 /* These tcp optinos do not have the size octet */
 116 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 117
 118 static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 119
 120
 121 #ifndef TELNET_PORT
 122 #define TELNET_PORT     23
 123 #endif
 124 #ifndef BGP_PORT
 125 #define BGP_PORT        179
 126 #endif
 127 #define NETBIOS_SSN_PORT 139
 128 #ifndef NFS_PORT
 129 #define NFS_PORT        2049
 130 #endif
 131
 132 void
 133 tcp_print(register const u_char *bp, register u_int length,
 134           register const u_char *bp2)
 135 {
 136         register const struct tcphdr *tp;
 137         register const struct ip *ip;
 138         register u_char flags;
 139         register int hlen;
 140         register char ch;
 141         u_int16_t sport, dport, win, urp;
 142         u_int32_t seq, ack, thseq, thack;
 143         int threv;
 144 #ifdef INET6
 145         register const struct ip6_hdr *ip6;
 146 #endif
 147
 148         tp = (struct tcphdr *)bp;
 149         ip = (struct ip *)bp2;
 150 #ifdef INET6
 151         if (ip->ip_v == 6)
 152                 ip6 = (struct ip6_hdr *)bp2;
 153         else
 154                 ip6 = NULL;
 155 #endif /*INET6*/
 156         ch = '\0';
 157         if (!TTEST(tp->th_dport)) {
 158                 (void)printf("%s > %s: [|tcp]",
 159                         ipaddr_string(&ip->ip_src),
 160                         ipaddr_string(&ip->ip_dst));
 161                 return;
 162         }
 163
 164         sport = ntohs(tp->th_sport);
 165         dport = ntohs(tp->th_dport);
 166
 167
 168         hlen = tp->th_off * 4;
 169
 170         /*
 171          * If data present and NFS port used, assume NFS.
 172          * Pass offset of data plus 4 bytes for RPC TCP msg length
 173          * to NFS print routines.
 174          */
 175         if (!qflag) {
 176                 if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend &&
 177                     dport == NFS_PORT) {
 178                         nfsreq_print((u_char *)tp + hlen + 4, length-hlen,
 179                                      (u_char *)ip);
 180                         return;
 181                 } else if ((u_char *)tp + 4 + sizeof(struct rpc_msg)
 182                            <= snapend &&
 183                            sport == NFS_PORT) {
 184                         nfsreply_print((u_char *)tp + hlen + 4,length-hlen,
 185                                        (u_char *)ip);
 186                         return;
 187                 }
 188         }
 189 #ifdef INET6
 190         if (ip6) {
 191                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 192                         (void)printf("%s.%s > %s.%s: ",
 193                                 ip6addr_string(&ip6->ip6_src),
 194                                 tcpport_string(sport),
 195                                 ip6addr_string(&ip6->ip6_dst),
 196                                 tcpport_string(dport));
 197                 } else {
 198                         (void)printf("%s > %s: ",
 199                                 tcpport_string(sport), tcpport_string(dport));
 200                 }
 201         } else
 202 #endif /*INET6*/
 203         {
 204                 if (ip->ip_p == IPPROTO_TCP) {
 205                         (void)printf("%s.%s > %s.%s: ",
 206                                 ipaddr_string(&ip->ip_src),
 207                                 tcpport_string(sport),
 208                                 ipaddr_string(&ip->ip_dst),
 209                                 tcpport_string(dport));
 210                 } else {
 211                         (void)printf("%s > %s: ",
 212                                 tcpport_string(sport), tcpport_string(dport));
 213                 }
 214         }
 215
 216         TCHECK(*tp);
 217
 218         seq = (u_int32_t)ntohl(tp->th_seq);
 219         ack = (u_int32_t)ntohl(tp->th_ack);
 220         win = ntohs(tp->th_win);
 221         urp = ntohs(tp->th_urp);
 222
 223         if (qflag) {
 224                 (void)printf("tcp %d", length - tp->th_off * 4);
 225                 return;
 226         }
 227         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|
 228                                       TH_ECNECHO|TH_CWR)) {
 229                 if (flags & TH_SYN)
 230                         putchar('S');
 231                 if (flags & TH_FIN)
 232                         putchar('F');
 233                 if (flags & TH_RST)
 234                         putchar('R');
 235                 if (flags & TH_PUSH)
 236                         putchar('P');
 237                 if (flags & TH_CWR)
 238                         putchar('W');   /* congestion _W_indow reduced (ECN) */
 239                 if (flags & TH_ECNECHO)
 240                         putchar('E');   /* ecn _E_cho sent (ECN) */
 241         } else
 242                 putchar('.');
 243
 244         if (!Sflag && (flags & TH_ACK)) {
 245                 register struct tcp_seq_hash *th;
 246                 register int rev;
 247                 struct tha tha;
 248                 /*
 249                  * Find (or record) the initial sequence numbers for
 250                  * this conversation.  (we pick an arbitrary
 251                  * collating order so there's only one entry for
 252                  * both directions).
 253                  */
 254 #ifdef INET6
 255                 memset(&tha, 0, sizeof(tha));
 256                 rev = 0;
 257                 if (ip6) {
 258                         if (sport > dport) {
 259                                 rev = 1;
 260                         } else if (sport == dport) {
 261                             int i;
 262
 263                             for (i = 0; i < 4; i++) {
 264                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 265                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 266                                         rev = 1;
 267                                         break;
 268                                 }
 269                             }
 270                         }
 271                         if (rev) {
 272                                 tha.src = ip6->ip6_dst;
 273                                 tha.dst = ip6->ip6_src;
 274                                 tha.port = dport << 16 | sport;
 275                         } else {
 276                                 tha.dst = ip6->ip6_dst;
 277                                 tha.src = ip6->ip6_src;
 278                                 tha.port = sport << 16 | dport;
 279                         }
 280                 } else {
 281                         if (sport > dport ||
 282                             (sport == dport &&
 283                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 284                                 rev = 1;
 285                         }
 286                         if (rev) {
 287                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 288                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 289                                 tha.port = dport << 16 | sport;
 290                         } else {
 291                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 292                                 *(struct in_addr *)&tha.src = ip->ip_src;
 293                                 tha.port = sport << 16 | dport;
 294                         }
 295                 }
 296 #else
 297                 if (sport < dport ||
 298                     (sport == dport &&
 299                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 300                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 301                         tha.port = sport << 16 | dport;
 302                         rev = 0;
 303                 } else {
 304                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 305                         tha.port = dport << 16 | sport;
 306                         rev = 1;
 307                 }
 308 #endif
 309
 310                 threv = rev;
 311                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 312                      th->nxt; th = th->nxt)
 313                         if (!memcmp((char *)&tha, (char *)&th->addr,
 314                                   sizeof(th->addr)))
 315                                 break;
 316
 317                 if (!th->nxt || (flags & TH_SYN)) {
 318                         /* didn't find it or new conversation */
 319                         if (th->nxt == NULL) {
 320                                 th->nxt = (struct tcp_seq_hash *)
 321                                         calloc(1, sizeof(*th));
 322                                 if (th->nxt == NULL)
 323                                         error("tcp_print: calloc");
 324                         }
 325                         th->addr = tha;
 326                         if (rev)
 327                                 th->ack = seq, th->seq = ack - 1;
 328                         else
 329                                 th->seq = seq, th->ack = ack - 1;
 330
 331                 } else {
 332                         if (rev)
 333                                 seq -= th->ack, ack -= th->seq;
 334                         else
 335                                 seq -= th->seq, ack -= th->ack;
 336                 }
 337
 338                 thseq = th->seq;
 339                 thack = th->ack;
 340         } else {
 341                 /*fool gcc*/
 342                 thseq = thack = threv = 0;
 343         }
 344         if (hlen > length) {
 345                 (void)printf(" [bad hdr length]");
 346                 return;
 347         }
 348         length -= hlen;
 349         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 350                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 351         if (flags & TH_ACK)
 352                 (void)printf(" ack %u", ack);
 353
 354         (void)printf(" win %d", win);
 355
 356         if (flags & TH_URG)
 357                 (void)printf(" urg %d", urp);
 358         /*
 359          * Handle any options.
 360          */
 361         if ((hlen -= sizeof(*tp)) > 0) {
 362                 register const u_char *cp;
 363                 register int i, opt, len, datalen;
 364
 365                 cp = (const u_char *)tp + sizeof(*tp);
 366                 putchar(' ');
 367                 ch = '<';
 368                 while (hlen > 0) {
 369                         putchar(ch);
 370                         TCHECK(*cp);
 371                         opt = *cp++;
 372                         if (ZEROLENOPT(opt))
 373                                 len = 1;
 374                         else {
 375                                 TCHECK(*cp);
 376                                 len = *cp++;    /* total including type, len */
 377                                 if (len < 2 || len > hlen)
 378                                         goto bad;
 379                                 --hlen;         /* account for length byte */
 380                         }
 381                         --hlen;                 /* account for type byte */
 382                         datalen = 0;
 383
 384 /* Bail if "l" bytes of data are not left or were not captured  */
 385 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 386
 387                         switch (opt) {
 388
 389                         case TCPOPT_MAXSEG:
 390                                 (void)printf("mss");
 391                                 datalen = 2;
 392                                 LENCHECK(datalen);
 393                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 394
 395                                 break;
 396
 397                         case TCPOPT_EOL:
 398                                 (void)printf("eol");
 399                                 break;
 400
 401                         case TCPOPT_NOP:
 402                                 (void)printf("nop");
 403                                 break;
 404
 405                         case TCPOPT_WSCALE:
 406                                 (void)printf("wscale");
 407                                 datalen = 1;
 408                                 LENCHECK(datalen);
 409                                 (void)printf(" %u", *cp);
 410                                 break;
 411
 412                         case TCPOPT_SACKOK:
 413                                 (void)printf("sackOK");
 414                                 break;
 415
 416                         case TCPOPT_SACK:
 417                                 (void)printf("sack");
 418                                 datalen = len - 2;
 419                                 if (datalen % 8 != 0) {
 420                                         (void)printf(" malformed sack ");
 421                                 } else {
 422                                         u_int32_t s, e;
 423
 424                                         (void)printf(" sack %d ", datalen / 8);
 425                                         for (i = 0; i < datalen; i += 8) {
 426                                                 LENCHECK(i + 4);
 427                                                 s = EXTRACT_32BITS(cp + i);
 428                                                 LENCHECK(i + 8);
 429                                                 e = EXTRACT_32BITS(cp + i + 4);
 430                                                 if (threv) {
 431                                                         s -= thseq;
 432                                                         e -= thseq;
 433                                                 } else {
 434                                                         s -= thack;
 435                                                         e -= thack;
 436                                                 }
 437                                                 (void)printf("{%u:%u}", s, e);
 438                                         }
 439                                         (void)printf(" ");
 440                                 }
 441                                 break;
 442
 443                         case TCPOPT_ECHO:
 444                                 (void)printf("echo");
 445                                 datalen = 4;
 446                                 LENCHECK(datalen);
 447                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 448                                 break;
 449
 450                         case TCPOPT_ECHOREPLY:
 451                                 (void)printf("echoreply");
 452                                 datalen = 4;
 453                                 LENCHECK(datalen);
 454                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 455                                 break;
 456
 457                         case TCPOPT_TIMESTAMP:
 458                                 (void)printf("timestamp");
 459                                 datalen = 8;
 460                                 LENCHECK(4);
 461                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 462                                 LENCHECK(datalen);
 463                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 464                                 break;
 465
 466                         case TCPOPT_CC:
 467                                 (void)printf("cc");
 468                                 datalen = 4;
 469                                 LENCHECK(datalen);
 470                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 471                                 break;
 472
 473                         case TCPOPT_CCNEW:
 474                                 (void)printf("ccnew");
 475                                 datalen = 4;
 476                                 LENCHECK(datalen);
 477                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 478                                 break;
 479
 480                         case TCPOPT_CCECHO:
 481                                 (void)printf("ccecho");
 482                                 datalen = 4;
 483                                 LENCHECK(datalen);
 484                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 485                                 break;
 486
 487                         default:
 488                                 (void)printf("opt-%d:", opt);
 489                                 datalen = len - 2;
 490                                 for (i = 0; i < datalen; ++i) {
 491                                         LENCHECK(i);
 492                                         (void)printf("%02x", cp[i]);
 493                                 }
 494                                 break;
 495                         }
 496
 497                         /* Account for data printed */
 498                         cp += datalen;
 499                         hlen -= datalen;
 500
 501                         /* Check specification against observed length */
 502                         ++datalen;                      /* option octet */
 503                         if (!ZEROLENOPT(opt))
 504                                 ++datalen;              /* size octet */
 505                         if (datalen != len)
 506                                 (void)printf("[len %d]", len);
 507                         ch = ',';
 508                         if (opt == TCPOPT_EOL)
 509                                 break;
 510                 }
 511                 putchar('>');
 512         }
 513
 514         if (length <= 0)
 515                 return;
 516
 517         /*
 518          * Decode payload if necessary.
 519          */
 520         bp += (tp->th_off * 4);
 521         if (!qflag && vflag && length > 0
 522          && (sport == TELNET_PORT || dport == TELNET_PORT))
 523                 telnet_print(bp, length);
 524         else if (sport == BGP_PORT || dport == BGP_PORT)
 525                 bgp_print(bp, length);
 526         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 527                 nbt_tcp_print(bp, length);
 528         return;
 529 bad:
 530         fputs("[bad opt]", stdout);
 531         if (ch != '\0')
 532                 putchar('>');
 533         return;
 534 trunc:
 535         fputs("[|tcp]", stdout);
 536         if (ch != '\0')
 537                 putchar('>');
 538 }
 539