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 1.66 2000-06-01 01:09:32 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 #ifdef HAVE_MEMORY_H
  43 #include <memory.h>
  44 #endif
  45 #include <stdio.h>
  46 #include <stdlib.h>
  47 #include <string.h>
  48 #include <unistd.h>
  49
  50 #ifdef INET6
  51 #include <netinet/ip6.h>
  52 #endif
  53
  54 #include "interface.h"
  55 #include "addrtoname.h"
  56 #include "extract.h"
  57
  58 /* Compatibility */
  59 #ifndef TCPOPT_WSCALE
  60 #define TCPOPT_WSCALE           3       /* window scale factor (rfc1072) */
  61 #endif
  62 #ifndef TCPOPT_SACKOK
  63 #define TCPOPT_SACKOK           4       /* selective ack ok (rfc1072) */
  64 #endif
  65 #ifndef TCPOPT_SACK
  66 #define TCPOPT_SACK             5       /* selective ack (rfc1072) */
  67 #endif
  68 #ifndef TCPOPT_ECHO
  69 #define TCPOPT_ECHO             6       /* echo (rfc1072) */
  70 #endif
  71 #ifndef TCPOPT_ECHOREPLY
  72 #define TCPOPT_ECHOREPLY        7       /* echo (rfc1072) */
  73 #endif
  74 #ifndef TCPOPT_TIMESTAMP
  75 #define TCPOPT_TIMESTAMP        8       /* timestamps (rfc1323) */
  76 #endif
  77 #ifndef TCPOPT_CC
  78 #define TCPOPT_CC               11      /* T/TCP CC options (rfc1644) */
  79 #endif
  80 #ifndef TCPOPT_CCNEW
  81 #define TCPOPT_CCNEW            12      /* T/TCP CC options (rfc1644) */
  82 #endif
  83 #ifndef TCPOPT_CCECHO
  84 #define TCPOPT_CCECHO           13      /* T/TCP CC options (rfc1644) */
  85 #endif
  86
  87 /*
  88  * Definitions required for ECN
  89  * for use if the OS running tcpdump does not have ECN
  90  */
  91 #ifndef TH_ECNECHO
  92 #define TH_ECNECHO              0x40    /* ECN Echo in tcp header */
  93 #endif
  94 #ifndef TH_CWR
  95 #define TH_CWR                  0x80    /* ECN Cwnd Reduced in tcp header*/
  96 #endif
  97
  98 struct tha {
  99 #ifndef INET6
 100         struct in_addr src;
 101         struct in_addr dst;
 102 #else
 103         struct in6_addr src;
 104         struct in6_addr dst;
 105 #endif /*INET6*/
 106         u_int port;
 107 };
 108
 109 struct tcp_seq_hash {
 110         struct tcp_seq_hash *nxt;
 111         struct tha addr;
 112         tcp_seq seq;
 113         tcp_seq ack;
 114 };
 115
 116 #define TSEQ_HASHSIZE 919
 117
 118 /* These tcp optinos do not have the size octet */
 119 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 120
 121 static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 122
 123
 124 #ifndef TELNET_PORT
 125 #define TELNET_PORT     23
 126 #endif
 127 #ifndef BGP_PORT
 128 #define BGP_PORT        179
 129 #endif
 130 #define NETBIOS_SSN_PORT 139
 131 #ifndef NFS_PORT
 132 #define NFS_PORT        2049
 133 #endif
 134
 135 void
 136 tcp_print(register const u_char *bp, register u_int length,
 137           register const u_char *bp2)
 138 {
 139         register const struct tcphdr *tp;
 140         register const struct ip *ip;
 141         register u_char flags;
 142         register int hlen;
 143         register char ch;
 144         u_int16_t sport, dport, win, urp;
 145         u_int32_t seq, ack, thseq, thack;
 146         int threv;
 147 #ifdef INET6
 148         register const struct ip6_hdr *ip6;
 149 #endif
 150
 151         tp = (struct tcphdr *)bp;
 152         ip = (struct ip *)bp2;
 153 #ifdef INET6
 154         if (ip->ip_v == 6)
 155                 ip6 = (struct ip6_hdr *)bp2;
 156         else
 157                 ip6 = NULL;
 158 #endif /*INET6*/
 159         ch = '\0';
 160         if (!TTEST(tp->th_dport)) {
 161                 (void)printf("%s > %s: [|tcp]",
 162                         ipaddr_string(&ip->ip_src),
 163                         ipaddr_string(&ip->ip_dst));
 164                 return;
 165         }
 166
 167         sport = ntohs(tp->th_sport);
 168         dport = ntohs(tp->th_dport);
 169
 170
 171         hlen = tp->th_off * 4;
 172
 173         /*
 174          * If data present and NFS port used, assume NFS.
 175          * Pass offset of data plus 4 bytes for RPC TCP msg length
 176          * to NFS print routines.
 177          */
 178         if (!qflag) {
 179                 if ((u_char *)tp + 4 + sizeof(struct rpc_msg) <= snapend &&
 180                     dport == NFS_PORT) {
 181                         nfsreq_print((u_char *)tp + hlen + 4, length-hlen,
 182                                      (u_char *)ip);
 183                         return;
 184                 } else if ((u_char *)tp + 4 + sizeof(struct rpc_msg)
 185                            <= snapend &&
 186                            sport == NFS_PORT) {
 187                         nfsreply_print((u_char *)tp + hlen + 4,length-hlen,
 188                                        (u_char *)ip);
 189                         return;
 190                 }
 191         }
 192 #ifdef INET6
 193         if (ip6) {
 194                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 195                         (void)printf("%s.%s > %s.%s: ",
 196                                 ip6addr_string(&ip6->ip6_src),
 197                                 tcpport_string(sport),
 198                                 ip6addr_string(&ip6->ip6_dst),
 199                                 tcpport_string(dport));
 200                 } else {
 201                         (void)printf("%s > %s: ",
 202                                 tcpport_string(sport), tcpport_string(dport));
 203                 }
 204         } else
 205 #endif /*INET6*/
 206         {
 207                 if (ip->ip_p == IPPROTO_TCP) {
 208                         (void)printf("%s.%s > %s.%s: ",
 209                                 ipaddr_string(&ip->ip_src),
 210                                 tcpport_string(sport),
 211                                 ipaddr_string(&ip->ip_dst),
 212                                 tcpport_string(dport));
 213                 } else {
 214                         (void)printf("%s > %s: ",
 215                                 tcpport_string(sport), tcpport_string(dport));
 216                 }
 217         }
 218
 219         TCHECK(*tp);
 220
 221         seq = (u_int32_t)ntohl(tp->th_seq);
 222         ack = (u_int32_t)ntohl(tp->th_ack);
 223         win = ntohs(tp->th_win);
 224         urp = ntohs(tp->th_urp);
 225
 226         if (qflag) {
 227                 (void)printf("tcp %d", length - tp->th_off * 4);
 228                 return;
 229         }
 230         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|
 231                                       TH_ECNECHO|TH_CWR)) {
 232                 if (flags & TH_SYN)
 233                         putchar('S');
 234                 if (flags & TH_FIN)
 235                         putchar('F');
 236                 if (flags & TH_RST)
 237                         putchar('R');
 238                 if (flags & TH_PUSH)
 239                         putchar('P');
 240                 if (flags & TH_CWR)
 241                         putchar('W');   /* congestion _W_indow reduced (ECN) */
 242                 if (flags & TH_ECNECHO)
 243                         putchar('E');   /* ecn _E_cho sent (ECN) */
 244         } else
 245                 putchar('.');
 246
 247         if (!Sflag && (flags & TH_ACK)) {
 248                 register struct tcp_seq_hash *th;
 249                 register int rev;
 250                 struct tha tha;
 251                 /*
 252                  * Find (or record) the initial sequence numbers for
 253                  * this conversation.  (we pick an arbitrary
 254                  * collating order so there's only one entry for
 255                  * both directions).
 256                  */
 257 #ifdef INET6
 258                 bzero(&tha, sizeof(tha));
 259                 rev = 0;
 260                 if (ip6) {
 261                         if (sport > dport) {
 262                                 rev = 1;
 263                         } else if (sport == dport) {
 264                             int i;
 265
 266                             for (i = 0; i < 4; i++) {
 267                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 268                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 269                                         rev = 1;
 270                                         break;
 271                                 }
 272                             }
 273                         }
 274                         if (rev) {
 275                                 tha.src = ip6->ip6_dst;
 276                                 tha.dst = ip6->ip6_src;
 277                                 tha.port = dport << 16 | sport;
 278                         } else {
 279                                 tha.dst = ip6->ip6_dst;
 280                                 tha.src = ip6->ip6_src;
 281                                 tha.port = sport << 16 | dport;
 282                         }
 283                 } else {
 284                         if (sport > dport ||
 285                             (sport == dport &&
 286                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 287                                 rev = 1;
 288                         }
 289                         if (rev) {
 290                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 291                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 292                                 tha.port = dport << 16 | sport;
 293                         } else {
 294                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 295                                 *(struct in_addr *)&tha.src = ip->ip_src;
 296                                 tha.port = sport << 16 | dport;
 297                         }
 298                 }
 299 #else
 300                 if (sport < dport ||
 301                     (sport == dport &&
 302                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 303                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 304                         tha.port = sport << 16 | dport;
 305                         rev = 0;
 306                 } else {
 307                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 308                         tha.port = dport << 16 | sport;
 309                         rev = 1;
 310                 }
 311 #endif
 312
 313                 threv = rev;
 314                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 315                      th->nxt; th = th->nxt)
 316                         if (!memcmp((char *)&tha, (char *)&th->addr,
 317                                   sizeof(th->addr)))
 318                                 break;
 319
 320                 if (!th->nxt || (flags & TH_SYN)) {
 321                         /* didn't find it or new conversation */
 322                         if (th->nxt == NULL) {
 323                                 th->nxt = (struct tcp_seq_hash *)
 324                                         calloc(1, sizeof(*th));
 325                                 if (th->nxt == NULL)
 326                                         error("tcp_print: calloc");
 327                         }
 328                         th->addr = tha;
 329                         if (rev)
 330                                 th->ack = seq, th->seq = ack - 1;
 331                         else
 332                                 th->seq = seq, th->ack = ack - 1;
 333
 334                 } else {
 335                         if (rev)
 336                                 seq -= th->ack, ack -= th->seq;
 337                         else
 338                                 seq -= th->seq, ack -= th->ack;
 339                 }
 340
 341                 thseq = th->seq;
 342                 thack = th->ack;
 343         } else {
 344                 /*fool gcc*/
 345                 thseq = thack = threv = 0;
 346         }
 347         if (hlen > length) {
 348                 (void)printf(" [bad hdr length]");
 349                 return;
 350         }
 351         length -= hlen;
 352         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 353                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 354         if (flags & TH_ACK)
 355                 (void)printf(" ack %u", ack);
 356
 357         (void)printf(" win %d", win);
 358
 359         if (flags & TH_URG)
 360                 (void)printf(" urg %d", urp);
 361         /*
 362          * Handle any options.
 363          */
 364         if ((hlen -= sizeof(*tp)) > 0) {
 365                 register const u_char *cp;
 366                 register int i, opt, len, datalen;
 367
 368                 cp = (const u_char *)tp + sizeof(*tp);
 369                 putchar(' ');
 370                 ch = '<';
 371                 while (hlen > 0) {
 372                         putchar(ch);
 373                         TCHECK(*cp);
 374                         opt = *cp++;
 375                         if (ZEROLENOPT(opt))
 376                                 len = 1;
 377                         else {
 378                                 TCHECK(*cp);
 379                                 len = *cp++;    /* total including type, len */
 380                                 if (len < 2 || len > hlen)
 381                                         goto bad;
 382                                 --hlen;         /* account for length byte */
 383                         }
 384                         --hlen;                 /* account for type byte */
 385                         datalen = 0;
 386
 387 /* Bail if "l" bytes of data are not left or were not captured  */
 388 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 389
 390                         switch (opt) {
 391
 392                         case TCPOPT_MAXSEG:
 393                                 (void)printf("mss");
 394                                 datalen = 2;
 395                                 LENCHECK(datalen);
 396                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 397
 398                                 break;
 399
 400                         case TCPOPT_EOL:
 401                                 (void)printf("eol");
 402                                 break;
 403
 404                         case TCPOPT_NOP:
 405                                 (void)printf("nop");
 406                                 break;
 407
 408                         case TCPOPT_WSCALE:
 409                                 (void)printf("wscale");
 410                                 datalen = 1;
 411                                 LENCHECK(datalen);
 412                                 (void)printf(" %u", *cp);
 413                                 break;
 414
 415                         case TCPOPT_SACKOK:
 416                                 (void)printf("sackOK");
 417                                 break;
 418
 419                         case TCPOPT_SACK:
 420                                 (void)printf("sack");
 421                                 datalen = len - 2;
 422                                 if (datalen % 8 != 0) {
 423                                         (void)printf(" malformed sack ");
 424                                 } else {
 425                                         u_int32_t s, e;
 426
 427                                         (void)printf(" sack %d ", datalen / 8);
 428                                         for (i = 0; i < datalen; i += 8) {
 429                                                 LENCHECK(i + 4);
 430                                                 s = EXTRACT_32BITS(cp + i);
 431                                                 LENCHECK(i + 8);
 432                                                 e = EXTRACT_32BITS(cp + i + 4);
 433                                                 if (threv) {
 434                                                         s -= thseq;
 435                                                         e -= thseq;
 436                                                 } else {
 437                                                         s -= thack;
 438                                                         e -= thack;
 439                                                 }
 440                                                 (void)printf("{%u:%u}", s, e);
 441                                         }
 442                                         (void)printf(" ");
 443                                 }
 444                                 break;
 445
 446                         case TCPOPT_ECHO:
 447                                 (void)printf("echo");
 448                                 datalen = 4;
 449                                 LENCHECK(datalen);
 450                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 451                                 break;
 452
 453                         case TCPOPT_ECHOREPLY:
 454                                 (void)printf("echoreply");
 455                                 datalen = 4;
 456                                 LENCHECK(datalen);
 457                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 458                                 break;
 459
 460                         case TCPOPT_TIMESTAMP:
 461                                 (void)printf("timestamp");
 462                                 datalen = 8;
 463                                 LENCHECK(4);
 464                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 465                                 LENCHECK(datalen);
 466                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 467                                 break;
 468
 469                         case TCPOPT_CC:
 470                                 (void)printf("cc");
 471                                 datalen = 4;
 472                                 LENCHECK(datalen);
 473                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 474                                 break;
 475
 476                         case TCPOPT_CCNEW:
 477                                 (void)printf("ccnew");
 478                                 datalen = 4;
 479                                 LENCHECK(datalen);
 480                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 481                                 break;
 482
 483                         case TCPOPT_CCECHO:
 484                                 (void)printf("ccecho");
 485                                 datalen = 4;
 486                                 LENCHECK(datalen);
 487                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 488                                 break;
 489
 490                         default:
 491                                 (void)printf("opt-%d:", opt);
 492                                 datalen = len - 2;
 493                                 for (i = 0; i < datalen; ++i) {
 494                                         LENCHECK(i);
 495                                         (void)printf("%02x", cp[i]);
 496                                 }
 497                                 break;
 498                         }
 499
 500                         /* Account for data printed */
 501                         cp += datalen;
 502                         hlen -= datalen;
 503
 504                         /* Check specification against observed length */
 505                         ++datalen;                      /* option octet */
 506                         if (!ZEROLENOPT(opt))
 507                                 ++datalen;              /* size octet */
 508                         if (datalen != len)
 509                                 (void)printf("[len %d]", len);
 510                         ch = ',';
 511                         if (opt == TCPOPT_EOL)
 512                                 break;
 513                 }
 514                 putchar('>');
 515         }
 516
 517         if (length <= 0)
 518                 return;
 519
 520         /*
 521          * Decode payload if necessary.
 522          */
 523         bp += (tp->th_off * 4);
 524         if (!qflag && vflag && length > 0
 525          && (sport == TELNET_PORT || dport == TELNET_PORT))
 526                 telnet_print(bp, length);
 527         else if (sport == BGP_PORT || dport == BGP_PORT)
 528                 bgp_print(bp, length);
 529         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 530                 nbt_tcp_print(bp, length);
 531         return;
 532 bad:
 533         fputs("[bad opt]", stdout);
 534         if (ch != '\0')
 535                 putchar('>');
 536         return;
 537 trunc:
 538         fputs("[|tcp]", stdout);
 539         if (ch != '\0')
 540                 putchar('>');
 541 }
 542