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 1.63 1999-12-22 15:44:10 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 struct tha {
  86 #ifndef INET6
  87         struct in_addr src;
  88         struct in_addr dst;
  89 #else
  90         struct in6_addr src;
  91         struct in6_addr dst;
  92 #endif /*INET6*/
  93         u_int port;
  94 };
  95
  96 struct tcp_seq_hash {
  97         struct tcp_seq_hash *nxt;
  98         struct tha addr;
  99         tcp_seq seq;
 100         tcp_seq ack;
 101 };
 102
 103 #define TSEQ_HASHSIZE 919
 104
 105 /* These tcp optinos do not have the size octet */
 106 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 107
 108 static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 109
 110
 111 #ifndef TELNET_PORT
 112 #define TELNET_PORT     23
 113 #endif
 114 #ifndef BGP_PORT
 115 #define BGP_PORT        179
 116 #endif
 117 #define NETBIOS_SSN_PORT 139
 118
 119 void
 120 tcp_print(register const u_char *bp, register u_int length,
 121           register const u_char *bp2)
 122 {
 123         register const struct tcphdr *tp;
 124         register const struct ip *ip;
 125         register u_char flags;
 126         register int hlen;
 127         register char ch;
 128         u_short sport, dport, win, urp;
 129         u_int32_t seq, ack, thseq, thack;
 130         int threv;
 131 #ifdef INET6
 132         register const struct ip6_hdr *ip6;
 133 #endif
 134
 135         tp = (struct tcphdr *)bp;
 136         ip = (struct ip *)bp2;
 137 #ifdef INET6
 138         if (ip->ip_v == 6)
 139                 ip6 = (struct ip6_hdr *)bp2;
 140         else
 141                 ip6 = NULL;
 142 #endif /*INET6*/
 143         ch = '\0';
 144         if (!TTEST(tp->th_dport)) {
 145                 (void)printf("%s > %s: [|tcp]",
 146                         ipaddr_string(&ip->ip_src),
 147                         ipaddr_string(&ip->ip_dst));
 148                 return;
 149         }
 150
 151         sport = ntohs(tp->th_sport);
 152         dport = ntohs(tp->th_dport);
 153
 154 #ifdef INET6
 155         if (ip6) {
 156                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 157                         (void)printf("%s.%s > %s.%s: ",
 158                                 ip6addr_string(&ip6->ip6_src),
 159                                 tcpport_string(sport),
 160                                 ip6addr_string(&ip6->ip6_dst),
 161                                 tcpport_string(dport));
 162                 } else {
 163                         (void)printf("%s > %s: ",
 164                                 tcpport_string(sport), tcpport_string(dport));
 165                 }
 166         } else
 167 #endif /*INET6*/
 168         {
 169                 if (ip->ip_p == IPPROTO_TCP) {
 170                         (void)printf("%s.%s > %s.%s: ",
 171                                 ipaddr_string(&ip->ip_src),
 172                                 tcpport_string(sport),
 173                                 ipaddr_string(&ip->ip_dst),
 174                                 tcpport_string(dport));
 175                 } else {
 176                         (void)printf("%s > %s: ",
 177                                 tcpport_string(sport), tcpport_string(dport));
 178                 }
 179         }
 180
 181         TCHECK(*tp);
 182
 183         seq = ntohl(tp->th_seq);
 184         ack = ntohl(tp->th_ack);
 185         win = ntohs(tp->th_win);
 186         urp = ntohs(tp->th_urp);
 187
 188         if (qflag) {
 189                 (void)printf("tcp %d", length - tp->th_off * 4);
 190                 return;
 191         }
 192 #ifdef TH_ECN
 193         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|TH_ECN))
 194 #else
 195         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH))
 196 #endif
 197         {
 198                 if (flags & TH_SYN)
 199                         putchar('S');
 200                 if (flags & TH_FIN)
 201                         putchar('F');
 202                 if (flags & TH_RST)
 203                         putchar('R');
 204                 if (flags & TH_PUSH)
 205                         putchar('P');
 206 #ifdef TH_ECN
 207                 if (flags & TH_ECN)
 208                         putchar('C');
 209 #endif
 210         } else
 211                 putchar('.');
 212
 213         if (flags&0xc0) {
 214                 printf(" [");
 215                 if (flags&0x40)
 216                         printf("ECN-Echo");
 217                 if (flags&0x80)
 218                         printf("%sCWR", (flags&0x40) ? "," : "");
 219                 printf("]");
 220         }
 221
 222         if (!Sflag && (flags & TH_ACK)) {
 223                 register struct tcp_seq_hash *th;
 224                 register int rev;
 225                 struct tha tha;
 226                 /*
 227                  * Find (or record) the initial sequence numbers for
 228                  * this conversation.  (we pick an arbitrary
 229                  * collating order so there's only one entry for
 230                  * both directions).
 231                  */
 232 #ifdef INET6
 233                 bzero(&tha, sizeof(tha));
 234                 rev = 0;
 235                 if (ip6) {
 236                         if (sport > dport) {
 237                                 rev = 1;
 238                         } else if (sport == dport) {
 239                             int i;
 240
 241                             for (i = 0; i < 4; i++) {
 242                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 243                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 244                                         rev = 1;
 245                                         break;
 246                                 }
 247                             }
 248                         }
 249                         if (rev) {
 250                                 tha.src = ip6->ip6_dst;
 251                                 tha.dst = ip6->ip6_src;
 252                                 tha.port = dport << 16 | sport;
 253                         } else {
 254                                 tha.dst = ip6->ip6_dst;
 255                                 tha.src = ip6->ip6_src;
 256                                 tha.port = sport << 16 | dport;
 257                         }
 258                 } else {
 259                         if (sport > dport ||
 260                             (sport == dport &&
 261                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 262                                 rev = 1;
 263                         }
 264                         if (rev) {
 265                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 266                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 267                                 tha.port = dport << 16 | sport;
 268                         } else {
 269                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 270                                 *(struct in_addr *)&tha.src = ip->ip_src;
 271                                 tha.port = sport << 16 | dport;
 272                         }
 273                 }
 274 #else
 275                 if (sport < dport ||
 276                     (sport == dport &&
 277                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 278                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 279                         tha.port = sport << 16 | dport;
 280                         rev = 0;
 281                 } else {
 282                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 283                         tha.port = dport << 16 | sport;
 284                         rev = 1;
 285                 }
 286 #endif
 287
 288                 threv = rev;
 289                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 290                      th->nxt; th = th->nxt)
 291                         if (!memcmp((char *)&tha, (char *)&th->addr,
 292                                   sizeof(th->addr)))
 293                                 break;
 294
 295                 if (!th->nxt || flags & TH_SYN) {
 296                         /* didn't find it or new conversation */
 297                         if (th->nxt == NULL) {
 298                                 th->nxt = (struct tcp_seq_hash *)
 299                                         calloc(1, sizeof(*th));
 300                                 if (th->nxt == NULL)
 301                                         error("tcp_print: calloc");
 302                         }
 303                         th->addr = tha;
 304                         if (rev)
 305                                 th->ack = seq, th->seq = ack - 1;
 306                         else
 307                                 th->seq = seq, th->ack = ack - 1;
 308                 } else {
 309
 310                         thseq = th->seq;
 311                         thack = th->ack;
 312
 313                         if (rev)
 314                                 seq -= th->ack, ack -= th->seq;
 315                         else
 316                                 seq -= th->seq, ack -= th->ack;
 317                 }
 318         }
 319         hlen = tp->th_off * 4;
 320         if (hlen > length) {
 321                 (void)printf(" [bad hdr length]");
 322                 return;
 323         }
 324         length -= hlen;
 325         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 326                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 327         if (flags & TH_ACK)
 328                 (void)printf(" ack %u", ack);
 329
 330         (void)printf(" win %d", win);
 331
 332         if (flags & TH_URG)
 333                 (void)printf(" urg %d", urp);
 334         /*
 335          * Handle any options.
 336          */
 337         if ((hlen -= sizeof(*tp)) > 0) {
 338                 register const u_char *cp;
 339                 register int i, opt, len, datalen;
 340
 341                 cp = (const u_char *)tp + sizeof(*tp);
 342                 putchar(' ');
 343                 ch = '<';
 344                 while (hlen > 0) {
 345                         putchar(ch);
 346                         TCHECK(*cp);
 347                         opt = *cp++;
 348                         if (ZEROLENOPT(opt))
 349                                 len = 1;
 350                         else {
 351                                 TCHECK(*cp);
 352                                 len = *cp++;    /* total including type, len */
 353                                 if (len < 2 || len > hlen)
 354                                         goto bad;
 355                                 --hlen;         /* account for length byte */
 356                         }
 357                         --hlen;                 /* account for type byte */
 358                         datalen = 0;
 359
 360 /* Bail if "l" bytes of data are not left or were not captured  */
 361 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 362
 363                         switch (opt) {
 364
 365                         case TCPOPT_MAXSEG:
 366                                 (void)printf("mss");
 367                                 datalen = 2;
 368                                 LENCHECK(datalen);
 369                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 370
 371                                 break;
 372
 373                         case TCPOPT_EOL:
 374                                 (void)printf("eol");
 375                                 break;
 376
 377                         case TCPOPT_NOP:
 378                                 (void)printf("nop");
 379                                 break;
 380
 381                         case TCPOPT_WSCALE:
 382                                 (void)printf("wscale");
 383                                 datalen = 1;
 384                                 LENCHECK(datalen);
 385                                 (void)printf(" %u", *cp);
 386                                 break;
 387
 388                         case TCPOPT_SACKOK:
 389                                 (void)printf("sackOK");
 390                                 break;
 391
 392                         case TCPOPT_SACK:
 393                                 (void)printf("sack");
 394                                 datalen = len - 2;
 395                                 if (datalen % 8 != 0) {
 396                                         (void)printf(" malformed sack ");
 397                                 } else {
 398                                         u_int32_t s, e;
 399
 400                                         (void)printf(" sack %d ", datalen / 8);
 401                                         for (i = 0; i < datalen; i += 8) {
 402                                                 LENCHECK(i + 4);
 403                                                 s = EXTRACT_32BITS(cp + i);
 404                                                 LENCHECK(i + 8);
 405                                                 e = EXTRACT_32BITS(cp + i + 4);
 406                                                 if (threv) {
 407                                                         s -= thseq;
 408                                                         e -= thseq;
 409                                                 } else {
 410                                                         s -= thack;
 411                                                         e -= thack;
 412                                                 }
 413                                                 (void)printf("{%u:%u}", s, e);
 414                                         }
 415                                         (void)printf(" ");
 416                                 }
 417                                 break;
 418
 419                         case TCPOPT_ECHO:
 420                                 (void)printf("echo");
 421                                 datalen = 4;
 422                                 LENCHECK(datalen);
 423                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 424                                 break;
 425
 426                         case TCPOPT_ECHOREPLY:
 427                                 (void)printf("echoreply");
 428                                 datalen = 4;
 429                                 LENCHECK(datalen);
 430                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 431                                 break;
 432
 433                         case TCPOPT_TIMESTAMP:
 434                                 (void)printf("timestamp");
 435                                 datalen = 8;
 436                                 LENCHECK(4);
 437                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 438                                 LENCHECK(datalen);
 439                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 440                                 break;
 441
 442                         case TCPOPT_CC:
 443                                 (void)printf("cc");
 444                                 datalen = 4;
 445                                 LENCHECK(datalen);
 446                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 447                                 break;
 448
 449                         case TCPOPT_CCNEW:
 450                                 (void)printf("ccnew");
 451                                 datalen = 4;
 452                                 LENCHECK(datalen);
 453                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 454                                 break;
 455
 456                         case TCPOPT_CCECHO:
 457                                 (void)printf("ccecho");
 458                                 datalen = 4;
 459                                 LENCHECK(datalen);
 460                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 461                                 break;
 462
 463                         default:
 464                                 (void)printf("opt-%d:", opt);
 465                                 datalen = len - 2;
 466                                 for (i = 0; i < datalen; ++i) {
 467                                         LENCHECK(i);
 468                                         (void)printf("%02x", cp[i]);
 469                                 }
 470                                 break;
 471                         }
 472
 473                         /* Account for data printed */
 474                         cp += datalen;
 475                         hlen -= datalen;
 476
 477                         /* Check specification against observed length */
 478                         ++datalen;                      /* option octet */
 479                         if (!ZEROLENOPT(opt))
 480                                 ++datalen;              /* size octet */
 481                         if (datalen != len)
 482                                 (void)printf("[len %d]", len);
 483                         ch = ',';
 484                         if (opt == TCPOPT_EOL)
 485                                 break;
 486                 }
 487                 putchar('>');
 488         }
 489
 490         if (length <= 0)
 491                 return;
 492
 493         /*
 494          * Decode payload if necessary.
 495          */
 496         bp += (tp->th_off * 4);
 497         if (!qflag && vflag && length > 0
 498          && (sport == TELNET_PORT || dport == TELNET_PORT))
 499                 telnet_print(bp, length);
 500         else if (sport == BGP_PORT || dport == BGP_PORT)
 501                 bgp_print(bp, length);
 502         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 503                 nbt_tcp_print(bp, length);
 504         return;
 505 bad:
 506         fputs("[bad opt]", stdout);
 507         if (ch != '\0')
 508                 putchar('>');
 509         return;
 510 trunc:
 511         fputs("[|tcp]", stdout);
 512         if (ch != '\0')
 513                 putchar('>');
 514 }
 515