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 1.58 1999-11-21 03:50:02 assar Exp $ (LBL)";
  25 #endif
  26
  27 #include <sys/param.h>
  28 #include <sys/time.h>
  29
  30 #include <netinet/in.h>
  31 #include <netinet/in_systm.h>
  32 #include <netinet/ip.h>
  33 #include <netinet/ip_var.h>
  34 #include <netinet/tcp.h>
  35
  36 #ifdef HAVE_MEMORY_H
  37 #include <memory.h>
  38 #endif
  39 #include <stdio.h>
  40 #include <stdlib.h>
  41 #include <string.h>
  42 #include <unistd.h>
  43
  44 #ifdef INET6
  45 #include <netinet/ip6.h>
  46 #endif
  47
  48 #include "interface.h"
  49 #include "addrtoname.h"
  50 #include "extract.h"
  51
  52 /* Compatibility */
  53 #ifndef TCPOPT_WSCALE
  54 #define TCPOPT_WSCALE           3       /* window scale factor (rfc1072) */
  55 #endif
  56 #ifndef TCPOPT_SACKOK
  57 #define TCPOPT_SACKOK           4       /* selective ack ok (rfc1072) */
  58 #endif
  59 #ifndef TCPOPT_SACK
  60 #define TCPOPT_SACK             5       /* selective ack (rfc1072) */
  61 #endif
  62 #ifndef TCPOPT_ECHO
  63 #define TCPOPT_ECHO             6       /* echo (rfc1072) */
  64 #endif
  65 #ifndef TCPOPT_ECHOREPLY
  66 #define TCPOPT_ECHOREPLY        7       /* echo (rfc1072) */
  67 #endif
  68 #ifndef TCPOPT_TIMESTAMP
  69 #define TCPOPT_TIMESTAMP        8       /* timestamps (rfc1323) */
  70 #endif
  71 #ifndef TCPOPT_CC
  72 #define TCPOPT_CC               11      /* T/TCP CC options (rfc1644) */
  73 #endif
  74 #ifndef TCPOPT_CCNEW
  75 #define TCPOPT_CCNEW            12      /* T/TCP CC options (rfc1644) */
  76 #endif
  77 #ifndef TCPOPT_CCECHO
  78 #define TCPOPT_CCECHO           13      /* T/TCP CC options (rfc1644) */
  79 #endif
  80
  81 struct tha {
  82 #ifndef INET6
  83         struct in_addr src;
  84         struct in_addr dst;
  85 #else
  86         struct in6_addr src;
  87         struct in6_addr dst;
  88 #endif /*INET6*/
  89         u_int port;
  90 };
  91
  92 struct tcp_seq_hash {
  93         struct tcp_seq_hash *nxt;
  94         struct tha addr;
  95         tcp_seq seq;
  96         tcp_seq ack;
  97 };
  98
  99 #define TSEQ_HASHSIZE 919
 100
 101 /* These tcp optinos do not have the size octet */
 102 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
 103
 104 static struct tcp_seq_hash tcp_seq_hash[TSEQ_HASHSIZE];
 105
 106
 107 void
 108 tcp_print(register const u_char *bp, register u_int length,
 109           register const u_char *bp2)
 110 {
 111         register const struct tcphdr *tp;
 112         register const struct ip *ip;
 113         register u_char flags;
 114         register int hlen;
 115         register char ch;
 116         u_short sport, dport, win, urp;
 117         u_int32_t seq, ack, thseq, thack;
 118         int threv;
 119 #ifdef INET6
 120         register const struct ip6_hdr *ip6;
 121 #endif
 122
 123         tp = (struct tcphdr *)bp;
 124         ip = (struct ip *)bp2;
 125 #ifdef INET6
 126         if (ip->ip_v == 6)
 127                 ip6 = (struct ip6_hdr *)bp2;
 128         else
 129                 ip6 = NULL;
 130 #endif /*INET6*/
 131         ch = '\0';
 132         TCHECK(*tp);
 133         if (length < sizeof(*tp)) {
 134                 (void)printf("truncated-tcp %d", length);
 135                 return;
 136         }
 137
 138         sport = ntohs(tp->th_sport);
 139         dport = ntohs(tp->th_dport);
 140         seq = ntohl(tp->th_seq);
 141         ack = ntohl(tp->th_ack);
 142         win = ntohs(tp->th_win);
 143         urp = ntohs(tp->th_urp);
 144
 145 #ifdef INET6
 146         if (ip6) {
 147                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 148                         (void)printf("%s.%s > %s.%s: ",
 149                                 ip6addr_string(&ip6->ip6_src),
 150                                 tcpport_string(sport),
 151                                 ip6addr_string(&ip6->ip6_dst),
 152                                 tcpport_string(dport));
 153                 } else {
 154                         (void)printf("%s > %s: ",
 155                                 tcpport_string(sport), tcpport_string(dport));
 156                 }
 157         } else
 158 #endif /*INET6*/
 159         {
 160                 if (ip->ip_p == IPPROTO_TCP) {
 161                         (void)printf("%s.%s > %s.%s: ",
 162                                 ipaddr_string(&ip->ip_src),
 163                                 tcpport_string(sport),
 164                                 ipaddr_string(&ip->ip_dst),
 165                                 tcpport_string(dport));
 166                 } else {
 167                         (void)printf("%s > %s: ",
 168                                 tcpport_string(sport), tcpport_string(dport));
 169                 }
 170         }
 171
 172         if (qflag) {
 173                 (void)printf("tcp %d", length - tp->th_off * 4);
 174                 return;
 175         }
 176 #ifdef TH_ECN
 177         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|TH_ECN)) {
 178 #else
 179         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH)) {
 180 #endif
 181                 if (flags & TH_SYN)
 182                         putchar('S');
 183                 if (flags & TH_FIN)
 184                         putchar('F');
 185                 if (flags & TH_RST)
 186                         putchar('R');
 187                 if (flags & TH_PUSH)
 188                         putchar('P');
 189 #ifdef TH_ECN
 190                 if (flags & TH_ECN)
 191                         putchar('C');
 192 #endif
 193         } else
 194                 putchar('.');
 195
 196         if (flags&0xc0) {
 197                 printf(" [");
 198                 if (flags&0x40)
 199                         printf("ECN-Echo");
 200                 if (flags&0x80)
 201                         printf("%sCWR", (flags&0x40) ? "," : "");
 202                 printf("]");
 203         }
 204
 205         if (!Sflag && (flags & TH_ACK)) {
 206                 register struct tcp_seq_hash *th;
 207                 register int rev;
 208                 struct tha tha;
 209                 /*
 210                  * Find (or record) the initial sequence numbers for
 211                  * this conversation.  (we pick an arbitrary
 212                  * collating order so there's only one entry for
 213                  * both directions).
 214                  */
 215 #ifdef INET6
 216                 bzero(&tha, sizeof(tha));
 217                 rev = 0;
 218                 if (ip6) {
 219                         if (sport > dport) {
 220                                 rev = 1;
 221                         } else if (sport == dport) {
 222                             int i;
 223
 224                             for (i = 0; i < 4; i++) {
 225                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 226                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 227                                         rev = 1;
 228                                         break;
 229                                 }
 230                             }
 231                         }
 232                         if (rev) {
 233                                 tha.src = ip6->ip6_dst;
 234                                 tha.dst = ip6->ip6_src;
 235                                 tha.port = dport << 16 | sport;
 236                         } else {
 237                                 tha.dst = ip6->ip6_dst;
 238                                 tha.src = ip6->ip6_src;
 239                                 tha.port = sport << 16 | dport;
 240                         }
 241                 } else {
 242                         if (sport > dport ||
 243                             (sport == dport &&
 244                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 245                                 rev = 1;
 246                         }
 247                         if (rev) {
 248                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 249                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 250                                 tha.port = dport << 16 | sport;
 251                         } else {
 252                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 253                                 *(struct in_addr *)&tha.src = ip->ip_src;
 254                                 tha.port = sport << 16 | dport;
 255                         }
 256                 }
 257 #else
 258                 if (sport < dport ||
 259                     (sport == dport &&
 260                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 261                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 262                         tha.port = sport << 16 | dport;
 263                         rev = 0;
 264                 } else {
 265                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 266                         tha.port = dport << 16 | sport;
 267                         rev = 1;
 268                 }
 269 #endif
 270
 271                 threv = rev;
 272                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 273                      th->nxt; th = th->nxt)
 274                         if (!memcmp((char *)&tha, (char *)&th->addr,
 275                                   sizeof(th->addr)))
 276                                 break;
 277
 278                 if (!th->nxt || flags & TH_SYN) {
 279                         /* didn't find it or new conversation */
 280                         if (th->nxt == NULL) {
 281                                 th->nxt = (struct tcp_seq_hash *)
 282                                         calloc(1, sizeof(*th));
 283                                 if (th->nxt == NULL)
 284                                         error("tcp_print: calloc");
 285                         }
 286                         th->addr = tha;
 287                         if (rev)
 288                                 th->ack = seq, th->seq = ack - 1;
 289                         else
 290                                 th->seq = seq, th->ack = ack - 1;
 291                 } else {
 292
 293                         thseq = th->seq;
 294                         thack = th->ack;
 295
 296                         if (rev)
 297                                 seq -= th->ack, ack -= th->seq;
 298                         else
 299                                 seq -= th->seq, ack -= th->ack;
 300                 }
 301         }
 302         hlen = tp->th_off * 4;
 303         if (hlen > length) {
 304                 (void)printf(" [bad hdr length]");
 305                 return;
 306         }
 307         length -= hlen;
 308         if (length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 309                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 310         if (flags & TH_ACK)
 311                 (void)printf(" ack %u", ack);
 312
 313         (void)printf(" win %d", win);
 314
 315         if (flags & TH_URG)
 316                 (void)printf(" urg %d", urp);
 317         /*
 318          * Handle any options.
 319          */
 320         if ((hlen -= sizeof(*tp)) > 0) {
 321                 register const u_char *cp;
 322                 register int i, opt, len, datalen;
 323
 324                 cp = (const u_char *)tp + sizeof(*tp);
 325                 putchar(' ');
 326                 ch = '<';
 327                 while (hlen > 0) {
 328                         putchar(ch);
 329                         TCHECK(*cp);
 330                         opt = *cp++;
 331                         if (ZEROLENOPT(opt))
 332                                 len = 1;
 333                         else {
 334                                 TCHECK(*cp);
 335                                 len = *cp++;    /* total including type, len */
 336                                 if (len < 2 || len > hlen)
 337                                         goto bad;
 338                                 --hlen;         /* account for length byte */
 339                         }
 340                         --hlen;                 /* account for type byte */
 341                         datalen = 0;
 342
 343 /* Bail if "l" bytes of data are not left or were not captured  */
 344 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 345
 346                         switch (opt) {
 347
 348                         case TCPOPT_MAXSEG:
 349                                 (void)printf("mss");
 350                                 datalen = 2;
 351                                 LENCHECK(datalen);
 352                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 353
 354                                 break;
 355
 356                         case TCPOPT_EOL:
 357                                 (void)printf("eol");
 358                                 break;
 359
 360                         case TCPOPT_NOP:
 361                                 (void)printf("nop");
 362                                 break;
 363
 364                         case TCPOPT_WSCALE:
 365                                 (void)printf("wscale");
 366                                 datalen = 1;
 367                                 LENCHECK(datalen);
 368                                 (void)printf(" %u", *cp);
 369                                 break;
 370
 371                         case TCPOPT_SACKOK:
 372                                 (void)printf("sackOK");
 373                                 break;
 374
 375                         case TCPOPT_SACK:
 376                                 (void)printf("sack");
 377                                 datalen = len - 2;
 378                                 if (datalen % 8 != 0) {
 379                                         (void)printf(" malformed sack ");
 380                                 } else {
 381                                         u_int32_t s, e;
 382
 383                                         (void)printf(" sack %d ", datalen / 8);
 384                                         for (i = 0; i < datalen; i += 8) {
 385                                                 LENCHECK(i + 4);
 386                                                 s = EXTRACT_32BITS(cp + i);
 387                                                 LENCHECK(i + 8);
 388                                                 e = EXTRACT_32BITS(cp + i + 4);
 389                                                 if (threv) {
 390                                                         s -= thseq;
 391                                                         e -= thseq;
 392                                                 } else {
 393                                                         s -= thack;
 394                                                         e -= thack;
 395                                                 }
 396                                                 (void)printf("{%u:%u}", s, e);
 397                                         }
 398                                         (void)printf(" ");
 399                                 }
 400                                 break;
 401
 402                         case TCPOPT_ECHO:
 403                                 (void)printf("echo");
 404                                 datalen = 4;
 405                                 LENCHECK(datalen);
 406                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 407                                 break;
 408
 409                         case TCPOPT_ECHOREPLY:
 410                                 (void)printf("echoreply");
 411                                 datalen = 4;
 412                                 LENCHECK(datalen);
 413                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 414                                 break;
 415
 416                         case TCPOPT_TIMESTAMP:
 417                                 (void)printf("timestamp");
 418                                 datalen = 8;
 419                                 LENCHECK(4);
 420                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 421                                 LENCHECK(datalen);
 422                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 423                                 break;
 424
 425                         case TCPOPT_CC:
 426                                 (void)printf("cc");
 427                                 datalen = 4;
 428                                 LENCHECK(datalen);
 429                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 430                                 break;
 431
 432                         case TCPOPT_CCNEW:
 433                                 (void)printf("ccnew");
 434                                 datalen = 4;
 435                                 LENCHECK(datalen);
 436                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 437                                 break;
 438
 439                         case TCPOPT_CCECHO:
 440                                 (void)printf("ccecho");
 441                                 datalen = 4;
 442                                 LENCHECK(datalen);
 443                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 444                                 break;
 445
 446                         default:
 447                                 (void)printf("opt-%d:", opt);
 448                                 datalen = len - 2;
 449                                 for (i = 0; i < datalen; ++i) {
 450                                         LENCHECK(i);
 451                                         (void)printf("%02x", cp[i]);
 452                                 }
 453                                 break;
 454                         }
 455
 456                         /* Account for data printed */
 457                         cp += datalen;
 458                         hlen -= datalen;
 459
 460                         /* Check specification against observed length */
 461                         ++datalen;                      /* option octet */
 462                         if (!ZEROLENOPT(opt))
 463                                 ++datalen;              /* size octet */
 464                         if (datalen != len)
 465                                 (void)printf("[len %d]", len);
 466                         ch = ',';
 467                         if (opt == TCPOPT_EOL)
 468                                 break;
 469                 }
 470                 putchar('>');
 471         }
 472
 473         if (length <= 0)
 474                 return;
 475
 476         /*
 477          * Decode payload if necessary.
 478          */
 479         bp += (tp->th_off * 4);
 480         if (sport == 179 || dport == 179)
 481                 bgp_print(bp, length);
 482         return;
 483 bad:
 484         fputs("[bad opt]", stdout);
 485         if (ch != '\0')
 486                 putchar('>');
 487         return;
 488 trunc:
 489         fputs("[|tcp]", stdout);
 490         if (ch != '\0')
 491                 putchar('>');
 492 }
 493