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 1.64 2000-04-27 11:09:08 itojun 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 <netinet/in.h>
  35 #include <netinet/in_systm.h>
  36 #include <netinet/ip.h>
  37 #include <netinet/ip_var.h>
  38 #include <netinet/tcp.h>
  39
  40 #ifdef HAVE_MEMORY_H
  41 #include <memory.h>
  42 #endif
  43 #include <stdio.h>
  44 #include <stdlib.h>
  45 #include <string.h>
  46 #include <unistd.h>
  47
  48 #ifdef INET6
  49 #include <netinet/ip6.h>
  50 #endif
  51
  52 #include "interface.h"
  53 #include "addrtoname.h"
  54 #include "extract.h"
  55
  56 /* Compatibility */
  57 #ifndef TCPOPT_WSCALE
  58 #define TCPOPT_WSCALE           3       /* window scale factor (rfc1072) */
  59 #endif
  60 #ifndef TCPOPT_SACKOK
  61 #define TCPOPT_SACKOK           4       /* selective ack ok (rfc1072) */
  62 #endif
  63 #ifndef TCPOPT_SACK
  64 #define TCPOPT_SACK             5       /* selective ack (rfc1072) */
  65 #endif
  66 #ifndef TCPOPT_ECHO
  67 #define TCPOPT_ECHO             6       /* echo (rfc1072) */
  68 #endif
  69 #ifndef TCPOPT_ECHOREPLY
  70 #define TCPOPT_ECHOREPLY        7       /* echo (rfc1072) */
  71 #endif
  72 #ifndef TCPOPT_TIMESTAMP
  73 #define TCPOPT_TIMESTAMP        8       /* timestamps (rfc1323) */
  74 #endif
  75 #ifndef TCPOPT_CC
  76 #define TCPOPT_CC               11      /* T/TCP CC options (rfc1644) */
  77 #endif
  78 #ifndef TCPOPT_CCNEW
  79 #define TCPOPT_CCNEW            12      /* T/TCP CC options (rfc1644) */
  80 #endif
  81 #ifndef TCPOPT_CCECHO
  82 #define TCPOPT_CCECHO           13      /* T/TCP CC options (rfc1644) */
  83 #endif
  84
  85 /*
  86  * Definitions required for ECN
  87  * for use if the OS running tcpdump does not have ECN
  88  */
  89 #ifndef TH_ECNECHO
  90 #define TH_ECNECHO              0x40    /* ECN Echo in tcp header */
  91 #endif
  92 #ifndef TH_CWR
  93 #define TH_CWR                  0x80    /* ECN Cwnd Reduced in tcp header*/
  94 #endif
  95
  96 struct tha {
  97 #ifndef INET6
  98         struct in_addr src;
  99         struct in_addr dst;
 100 #else
 101         struct in6_addr src;
 102         struct in6_addr dst;
 103 #endif /*INET6*/
 104         u_int port;
 105 };
 106
 107 struct tcp_seq_hash {
 108         struct tcp_seq_hash *nxt;
 109         struct tha addr;
 110         tcp_seq seq;
 111         tcp_seq ack;
 112 };
 113
 114 #define TSEQ_HASHSIZE 919
 115
 116 /* These tcp optinos do not have the size octet */
 117 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 118
 119 static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 120
 121
 122 #ifndef TELNET_PORT
 123 #define TELNET_PORT     23
 124 #endif
 125 #ifndef BGP_PORT
 126 #define BGP_PORT        179
 127 #endif
 128 #define NETBIOS_SSN_PORT 139
 129
 130 void
 131 tcp_print(register const u_char *bp, register u_int length,
 132           register const u_char *bp2)
 133 {
 134         register const struct tcphdr *tp;
 135         register const struct ip *ip;
 136         register u_char flags;
 137         register int hlen;
 138         register char ch;
 139         u_int16_t sport, dport, win, urp;
 140         u_int32_t seq, ack, thseq, thack;
 141         int threv;
 142 #ifdef INET6
 143         register const struct ip6_hdr *ip6;
 144 #endif
 145
 146         tp = (struct tcphdr *)bp;
 147         ip = (struct ip *)bp2;
 148 #ifdef INET6
 149         if (ip->ip_v == 6)
 150                 ip6 = (struct ip6_hdr *)bp2;
 151         else
 152                 ip6 = NULL;
 153 #endif /*INET6*/
 154         ch = '\0';
 155         if (!TTEST(tp->th_dport)) {
 156                 (void)printf("%s > %s: [|tcp]",
 157                         ipaddr_string(&ip->ip_src),
 158                         ipaddr_string(&ip->ip_dst));
 159                 return;
 160         }
 161
 162         sport = ntohs(tp->th_sport);
 163         dport = ntohs(tp->th_dport);
 164
 165 #ifdef INET6
 166         if (ip6) {
 167                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 168                         (void)printf("%s.%s > %s.%s: ",
 169                                 ip6addr_string(&ip6->ip6_src),
 170                                 tcpport_string(sport),
 171                                 ip6addr_string(&ip6->ip6_dst),
 172                                 tcpport_string(dport));
 173                 } else {
 174                         (void)printf("%s > %s: ",
 175                                 tcpport_string(sport), tcpport_string(dport));
 176                 }
 177         } else
 178 #endif /*INET6*/
 179         {
 180                 if (ip->ip_p == IPPROTO_TCP) {
 181                         (void)printf("%s.%s > %s.%s: ",
 182                                 ipaddr_string(&ip->ip_src),
 183                                 tcpport_string(sport),
 184                                 ipaddr_string(&ip->ip_dst),
 185                                 tcpport_string(dport));
 186                 } else {
 187                         (void)printf("%s > %s: ",
 188                                 tcpport_string(sport), tcpport_string(dport));
 189                 }
 190         }
 191
 192         TCHECK(*tp);
 193
 194         seq = (u_int32_t)ntohl(tp->th_seq);
 195         ack = (u_int32_t)ntohl(tp->th_ack);
 196         win = ntohs(tp->th_win);
 197         urp = ntohs(tp->th_urp);
 198
 199         if (qflag) {
 200                 (void)printf("tcp %d", length - tp->th_off * 4);
 201                 return;
 202         }
 203         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|
 204                                       TH_ECNECHO|TH_CWR)) {
 205                 if (flags & TH_SYN)
 206                         putchar('S');
 207                 if (flags & TH_FIN)
 208                         putchar('F');
 209                 if (flags & TH_RST)
 210                         putchar('R');
 211                 if (flags & TH_PUSH)
 212                         putchar('P');
 213                 if (flags & TH_CWR)
 214                         putchar('W');   /* congestion _W_indow reduced (ECN) */
 215                 if (flags & TH_ECNECHO)
 216                         putchar('E');   /* ecn _E_cho sent (ECN) */
 217         } else
 218                 putchar('.');
 219
 220         if (!Sflag && (flags & TH_ACK)) {
 221                 register struct tcp_seq_hash *th;
 222                 register int rev;
 223                 struct tha tha;
 224                 /*
 225                  * Find (or record) the initial sequence numbers for
 226                  * this conversation.  (we pick an arbitrary
 227                  * collating order so there's only one entry for
 228                  * both directions).
 229                  */
 230 #ifdef INET6
 231                 bzero(&tha, sizeof(tha));
 232                 rev = 0;
 233                 if (ip6) {
 234                         if (sport > dport) {
 235                                 rev = 1;
 236                         } else if (sport == dport) {
 237                             int i;
 238
 239                             for (i = 0; i < 4; i++) {
 240                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 241                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 242                                         rev = 1;
 243                                         break;
 244                                 }
 245                             }
 246                         }
 247                         if (rev) {
 248                                 tha.src = ip6->ip6_dst;
 249                                 tha.dst = ip6->ip6_src;
 250                                 tha.port = dport << 16 | sport;
 251                         } else {
 252                                 tha.dst = ip6->ip6_dst;
 253                                 tha.src = ip6->ip6_src;
 254                                 tha.port = sport << 16 | dport;
 255                         }
 256                 } else {
 257                         if (sport > dport ||
 258                             (sport == dport &&
 259                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 260                                 rev = 1;
 261                         }
 262                         if (rev) {
 263                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 264                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 265                                 tha.port = dport << 16 | sport;
 266                         } else {
 267                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 268                                 *(struct in_addr *)&tha.src = ip->ip_src;
 269                                 tha.port = sport << 16 | dport;
 270                         }
 271                 }
 272 #else
 273                 if (sport < dport ||
 274                     (sport == dport &&
 275                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 276                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 277                         tha.port = sport << 16 | dport;
 278                         rev = 0;
 279                 } else {
 280                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 281                         tha.port = dport << 16 | sport;
 282                         rev = 1;
 283                 }
 284 #endif
 285
 286                 threv = rev;
 287                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 288                      th->nxt; th = th->nxt)
 289                         if (!memcmp((char *)&tha, (char *)&th->addr,
 290                                   sizeof(th->addr)))
 291                                 break;
 292
 293                 if (!th->nxt || flags & TH_SYN) {
 294                         /* didn't find it or new conversation */
 295                         if (th->nxt == NULL) {
 296                                 th->nxt = (struct tcp_seq_hash *)
 297                                         calloc(1, sizeof(*th));
 298                                 if (th->nxt == NULL)
 299                                         error("tcp_print: calloc");
 300                         }
 301                         th->addr = tha;
 302                         if (rev)
 303                                 th->ack = seq, th->seq = ack - 1;
 304                         else
 305                                 th->seq = seq, th->ack = ack - 1;
 306                 } else {
 307
 308                         thseq = th->seq;
 309                         thack = th->ack;
 310
 311                         if (rev)
 312                                 seq -= th->ack, ack -= th->seq;
 313                         else
 314                                 seq -= th->seq, ack -= th->ack;
 315                 }
 316         }
 317         hlen = tp->th_off * 4;
 318         if (hlen > length) {
 319                 (void)printf(" [bad hdr length]");
 320                 return;
 321         }
 322         length -= hlen;
 323         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 324                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 325         if (flags & TH_ACK)
 326                 (void)printf(" ack %u", ack);
 327
 328         (void)printf(" win %d", win);
 329
 330         if (flags & TH_URG)
 331                 (void)printf(" urg %d", urp);
 332         /*
 333          * Handle any options.
 334          */
 335         if ((hlen -= sizeof(*tp)) > 0) {
 336                 register const u_char *cp;
 337                 register int i, opt, len, datalen;
 338
 339                 cp = (const u_char *)tp + sizeof(*tp);
 340                 putchar(' ');
 341                 ch = '<';
 342                 while (hlen > 0) {
 343                         putchar(ch);
 344                         TCHECK(*cp);
 345                         opt = *cp++;
 346                         if (ZEROLENOPT(opt))
 347                                 len = 1;
 348                         else {
 349                                 TCHECK(*cp);
 350                                 len = *cp++;    /* total including type, len */
 351                                 if (len < 2 || len > hlen)
 352                                         goto bad;
 353                                 --hlen;         /* account for length byte */
 354                         }
 355                         --hlen;                 /* account for type byte */
 356                         datalen = 0;
 357
 358 /* Bail if "l" bytes of data are not left or were not captured  */
 359 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 360
 361                         switch (opt) {
 362
 363                         case TCPOPT_MAXSEG:
 364                                 (void)printf("mss");
 365                                 datalen = 2;
 366                                 LENCHECK(datalen);
 367                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 368
 369                                 break;
 370
 371                         case TCPOPT_EOL:
 372                                 (void)printf("eol");
 373                                 break;
 374
 375                         case TCPOPT_NOP:
 376                                 (void)printf("nop");
 377                                 break;
 378
 379                         case TCPOPT_WSCALE:
 380                                 (void)printf("wscale");
 381                                 datalen = 1;
 382                                 LENCHECK(datalen);
 383                                 (void)printf(" %u", *cp);
 384                                 break;
 385
 386                         case TCPOPT_SACKOK:
 387                                 (void)printf("sackOK");
 388                                 break;
 389
 390                         case TCPOPT_SACK:
 391                                 (void)printf("sack");
 392                                 datalen = len - 2;
 393                                 if (datalen % 8 != 0) {
 394                                         (void)printf(" malformed sack ");
 395                                 } else {
 396                                         u_int32_t s, e;
 397
 398                                         (void)printf(" sack %d ", datalen / 8);
 399                                         for (i = 0; i < datalen; i += 8) {
 400                                                 LENCHECK(i + 4);
 401                                                 s = EXTRACT_32BITS(cp + i);
 402                                                 LENCHECK(i + 8);
 403                                                 e = EXTRACT_32BITS(cp + i + 4);
 404                                                 if (threv) {
 405                                                         s -= thseq;
 406                                                         e -= thseq;
 407                                                 } else {
 408                                                         s -= thack;
 409                                                         e -= thack;
 410                                                 }
 411                                                 (void)printf("{%u:%u}", s, e);
 412                                         }
 413                                         (void)printf(" ");
 414                                 }
 415                                 break;
 416
 417                         case TCPOPT_ECHO:
 418                                 (void)printf("echo");
 419                                 datalen = 4;
 420                                 LENCHECK(datalen);
 421                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 422                                 break;
 423
 424                         case TCPOPT_ECHOREPLY:
 425                                 (void)printf("echoreply");
 426                                 datalen = 4;
 427                                 LENCHECK(datalen);
 428                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 429                                 break;
 430
 431                         case TCPOPT_TIMESTAMP:
 432                                 (void)printf("timestamp");
 433                                 datalen = 8;
 434                                 LENCHECK(4);
 435                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 436                                 LENCHECK(datalen);
 437                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 438                                 break;
 439
 440                         case TCPOPT_CC:
 441                                 (void)printf("cc");
 442                                 datalen = 4;
 443                                 LENCHECK(datalen);
 444                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 445                                 break;
 446
 447                         case TCPOPT_CCNEW:
 448                                 (void)printf("ccnew");
 449                                 datalen = 4;
 450                                 LENCHECK(datalen);
 451                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 452                                 break;
 453
 454                         case TCPOPT_CCECHO:
 455                                 (void)printf("ccecho");
 456                                 datalen = 4;
 457                                 LENCHECK(datalen);
 458                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 459                                 break;
 460
 461                         default:
 462                                 (void)printf("opt-%d:", opt);
 463                                 datalen = len - 2;
 464                                 for (i = 0; i < datalen; ++i) {
 465                                         LENCHECK(i);
 466                                         (void)printf("%02x", cp[i]);
 467                                 }
 468                                 break;
 469                         }
 470
 471                         /* Account for data printed */
 472                         cp += datalen;
 473                         hlen -= datalen;
 474
 475                         /* Check specification against observed length */
 476                         ++datalen;                      /* option octet */
 477                         if (!ZEROLENOPT(opt))
 478                                 ++datalen;              /* size octet */
 479                         if (datalen != len)
 480                                 (void)printf("[len %d]", len);
 481                         ch = ',';
 482                         if (opt == TCPOPT_EOL)
 483                                 break;
 484                 }
 485                 putchar('>');
 486         }
 487
 488         if (length <= 0)
 489                 return;
 490
 491         /*
 492          * Decode payload if necessary.
 493          */
 494         bp += (tp->th_off * 4);
 495         if (!qflag && vflag && length > 0
 496          && (sport == TELNET_PORT || dport == TELNET_PORT))
 497                 telnet_print(bp, length);
 498         else if (sport == BGP_PORT || dport == BGP_PORT)
 499                 bgp_print(bp, length);
 500         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 501                 nbt_tcp_print(bp, length);
 502         return;
 503 bad:
 504         fputs("[bad opt]", stdout);
 505         if (ch != '\0')
 506                 putchar('>');
 507         return;
 508 trunc:
 509         fputs("[|tcp]", stdout);
 510         if (ch != '\0')
 511                 putchar('>');
 512 }
 513