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 1.61 1999-11-22 04:27:10 fenner 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 #define NETBIOS_SSN_PORT 139
 112
 113 void
 114 tcp_print(register const u_char *bp, register u_int length,
 115           register const u_char *bp2)
 116 {
 117         register const struct tcphdr *tp;
 118         register const struct ip *ip;
 119         register u_char flags;
 120         register int hlen;
 121         register char ch;
 122         u_short sport, dport, win, urp;
 123         u_int32_t seq, ack, thseq, thack;
 124         int threv;
 125 #ifdef INET6
 126         register const struct ip6_hdr *ip6;
 127 #endif
 128
 129         tp = (struct tcphdr *)bp;
 130         ip = (struct ip *)bp2;
 131 #ifdef INET6
 132         if (ip->ip_v == 6)
 133                 ip6 = (struct ip6_hdr *)bp2;
 134         else
 135                 ip6 = NULL;
 136 #endif /*INET6*/
 137         ch = '\0';
 138         if (!TTEST(tp->th_dport)) {
 139                 (void)printf("%s > %s: [|tcp]",
 140                         ipaddr_string(&ip->ip_src),
 141                         ipaddr_string(&ip->ip_dst));
 142                 return;
 143         }
 144
 145         sport = ntohs(tp->th_sport);
 146         dport = ntohs(tp->th_dport);
 147
 148 #ifdef INET6
 149         if (ip6) {
 150                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 151                         (void)printf("%s.%s > %s.%s: ",
 152                                 ip6addr_string(&ip6->ip6_src),
 153                                 tcpport_string(sport),
 154                                 ip6addr_string(&ip6->ip6_dst),
 155                                 tcpport_string(dport));
 156                 } else {
 157                         (void)printf("%s > %s: ",
 158                                 tcpport_string(sport), tcpport_string(dport));
 159                 }
 160         } else
 161 #endif /*INET6*/
 162         {
 163                 if (ip->ip_p == IPPROTO_TCP) {
 164                         (void)printf("%s.%s > %s.%s: ",
 165                                 ipaddr_string(&ip->ip_src),
 166                                 tcpport_string(sport),
 167                                 ipaddr_string(&ip->ip_dst),
 168                                 tcpport_string(dport));
 169                 } else {
 170                         (void)printf("%s > %s: ",
 171                                 tcpport_string(sport), tcpport_string(dport));
 172                 }
 173         }
 174
 175         TCHECK(*tp);
 176
 177         seq = ntohl(tp->th_seq);
 178         ack = ntohl(tp->th_ack);
 179         win = ntohs(tp->th_win);
 180         urp = ntohs(tp->th_urp);
 181
 182         if (qflag) {
 183                 (void)printf("tcp %d", length - tp->th_off * 4);
 184                 return;
 185         }
 186 #ifdef TH_ECN
 187         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|TH_ECN)) {
 188 #else
 189         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH)) {
 190 #endif
 191                 if (flags & TH_SYN)
 192                         putchar('S');
 193                 if (flags & TH_FIN)
 194                         putchar('F');
 195                 if (flags & TH_RST)
 196                         putchar('R');
 197                 if (flags & TH_PUSH)
 198                         putchar('P');
 199 #ifdef TH_ECN
 200                 if (flags & TH_ECN)
 201                         putchar('C');
 202 #endif
 203         } else
 204                 putchar('.');
 205
 206         if (flags&0xc0) {
 207                 printf(" [");
 208                 if (flags&0x40)
 209                         printf("ECN-Echo");
 210                 if (flags&0x80)
 211                         printf("%sCWR", (flags&0x40) ? "," : "");
 212                 printf("]");
 213         }
 214
 215         if (!Sflag && (flags & TH_ACK)) {
 216                 register struct tcp_seq_hash *th;
 217                 register int rev;
 218                 struct tha tha;
 219                 /*
 220                  * Find (or record) the initial sequence numbers for
 221                  * this conversation.  (we pick an arbitrary
 222                  * collating order so there's only one entry for
 223                  * both directions).
 224                  */
 225 #ifdef INET6
 226                 bzero(&tha, sizeof(tha));
 227                 rev = 0;
 228                 if (ip6) {
 229                         if (sport > dport) {
 230                                 rev = 1;
 231                         } else if (sport == dport) {
 232                             int i;
 233
 234                             for (i = 0; i < 4; i++) {
 235                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 236                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 237                                         rev = 1;
 238                                         break;
 239                                 }
 240                             }
 241                         }
 242                         if (rev) {
 243                                 tha.src = ip6->ip6_dst;
 244                                 tha.dst = ip6->ip6_src;
 245                                 tha.port = dport << 16 | sport;
 246                         } else {
 247                                 tha.dst = ip6->ip6_dst;
 248                                 tha.src = ip6->ip6_src;
 249                                 tha.port = sport << 16 | dport;
 250                         }
 251                 } else {
 252                         if (sport > dport ||
 253                             (sport == dport &&
 254                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 255                                 rev = 1;
 256                         }
 257                         if (rev) {
 258                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 259                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 260                                 tha.port = dport << 16 | sport;
 261                         } else {
 262                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 263                                 *(struct in_addr *)&tha.src = ip->ip_src;
 264                                 tha.port = sport << 16 | dport;
 265                         }
 266                 }
 267 #else
 268                 if (sport < dport ||
 269                     (sport == dport &&
 270                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 271                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 272                         tha.port = sport << 16 | dport;
 273                         rev = 0;
 274                 } else {
 275                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 276                         tha.port = dport << 16 | sport;
 277                         rev = 1;
 278                 }
 279 #endif
 280
 281                 threv = rev;
 282                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 283                      th->nxt; th = th->nxt)
 284                         if (!memcmp((char *)&tha, (char *)&th->addr,
 285                                   sizeof(th->addr)))
 286                                 break;
 287
 288                 if (!th->nxt || flags & TH_SYN) {
 289                         /* didn't find it or new conversation */
 290                         if (th->nxt == NULL) {
 291                                 th->nxt = (struct tcp_seq_hash *)
 292                                         calloc(1, sizeof(*th));
 293                                 if (th->nxt == NULL)
 294                                         error("tcp_print: calloc");
 295                         }
 296                         th->addr = tha;
 297                         if (rev)
 298                                 th->ack = seq, th->seq = ack - 1;
 299                         else
 300                                 th->seq = seq, th->ack = ack - 1;
 301                 } else {
 302
 303                         thseq = th->seq;
 304                         thack = th->ack;
 305
 306                         if (rev)
 307                                 seq -= th->ack, ack -= th->seq;
 308                         else
 309                                 seq -= th->seq, ack -= th->ack;
 310                 }
 311         }
 312         hlen = tp->th_off * 4;
 313         if (hlen > length) {
 314                 (void)printf(" [bad hdr length]");
 315                 return;
 316         }
 317         length -= hlen;
 318         if (vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 319                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 320         if (flags & TH_ACK)
 321                 (void)printf(" ack %u", ack);
 322
 323         (void)printf(" win %d", win);
 324
 325         if (flags & TH_URG)
 326                 (void)printf(" urg %d", urp);
 327         /*
 328          * Handle any options.
 329          */
 330         if ((hlen -= sizeof(*tp)) > 0) {
 331                 register const u_char *cp;
 332                 register int i, opt, len, datalen;
 333
 334                 cp = (const u_char *)tp + sizeof(*tp);
 335                 putchar(' ');
 336                 ch = '<';
 337                 while (hlen > 0) {
 338                         putchar(ch);
 339                         TCHECK(*cp);
 340                         opt = *cp++;
 341                         if (ZEROLENOPT(opt))
 342                                 len = 1;
 343                         else {
 344                                 TCHECK(*cp);
 345                                 len = *cp++;    /* total including type, len */
 346                                 if (len < 2 || len > hlen)
 347                                         goto bad;
 348                                 --hlen;         /* account for length byte */
 349                         }
 350                         --hlen;                 /* account for type byte */
 351                         datalen = 0;
 352
 353 /* Bail if "l" bytes of data are not left or were not captured  */
 354 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 355
 356                         switch (opt) {
 357
 358                         case TCPOPT_MAXSEG:
 359                                 (void)printf("mss");
 360                                 datalen = 2;
 361                                 LENCHECK(datalen);
 362                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 363
 364                                 break;
 365
 366                         case TCPOPT_EOL:
 367                                 (void)printf("eol");
 368                                 break;
 369
 370                         case TCPOPT_NOP:
 371                                 (void)printf("nop");
 372                                 break;
 373
 374                         case TCPOPT_WSCALE:
 375                                 (void)printf("wscale");
 376                                 datalen = 1;
 377                                 LENCHECK(datalen);
 378                                 (void)printf(" %u", *cp);
 379                                 break;
 380
 381                         case TCPOPT_SACKOK:
 382                                 (void)printf("sackOK");
 383                                 break;
 384
 385                         case TCPOPT_SACK:
 386                                 (void)printf("sack");
 387                                 datalen = len - 2;
 388                                 if (datalen % 8 != 0) {
 389                                         (void)printf(" malformed sack ");
 390                                 } else {
 391                                         u_int32_t s, e;
 392
 393                                         (void)printf(" sack %d ", datalen / 8);
 394                                         for (i = 0; i < datalen; i += 8) {
 395                                                 LENCHECK(i + 4);
 396                                                 s = EXTRACT_32BITS(cp + i);
 397                                                 LENCHECK(i + 8);
 398                                                 e = EXTRACT_32BITS(cp + i + 4);
 399                                                 if (threv) {
 400                                                         s -= thseq;
 401                                                         e -= thseq;
 402                                                 } else {
 403                                                         s -= thack;
 404                                                         e -= thack;
 405                                                 }
 406                                                 (void)printf("{%u:%u}", s, e);
 407                                         }
 408                                         (void)printf(" ");
 409                                 }
 410                                 break;
 411
 412                         case TCPOPT_ECHO:
 413                                 (void)printf("echo");
 414                                 datalen = 4;
 415                                 LENCHECK(datalen);
 416                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 417                                 break;
 418
 419                         case TCPOPT_ECHOREPLY:
 420                                 (void)printf("echoreply");
 421                                 datalen = 4;
 422                                 LENCHECK(datalen);
 423                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 424                                 break;
 425
 426                         case TCPOPT_TIMESTAMP:
 427                                 (void)printf("timestamp");
 428                                 datalen = 8;
 429                                 LENCHECK(4);
 430                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 431                                 LENCHECK(datalen);
 432                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 433                                 break;
 434
 435                         case TCPOPT_CC:
 436                                 (void)printf("cc");
 437                                 datalen = 4;
 438                                 LENCHECK(datalen);
 439                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 440                                 break;
 441
 442                         case TCPOPT_CCNEW:
 443                                 (void)printf("ccnew");
 444                                 datalen = 4;
 445                                 LENCHECK(datalen);
 446                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 447                                 break;
 448
 449                         case TCPOPT_CCECHO:
 450                                 (void)printf("ccecho");
 451                                 datalen = 4;
 452                                 LENCHECK(datalen);
 453                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 454                                 break;
 455
 456                         default:
 457                                 (void)printf("opt-%d:", opt);
 458                                 datalen = len - 2;
 459                                 for (i = 0; i < datalen; ++i) {
 460                                         LENCHECK(i);
 461                                         (void)printf("%02x", cp[i]);
 462                                 }
 463                                 break;
 464                         }
 465
 466                         /* Account for data printed */
 467                         cp += datalen;
 468                         hlen -= datalen;
 469
 470                         /* Check specification against observed length */
 471                         ++datalen;                      /* option octet */
 472                         if (!ZEROLENOPT(opt))
 473                                 ++datalen;              /* size octet */
 474                         if (datalen != len)
 475                                 (void)printf("[len %d]", len);
 476                         ch = ',';
 477                         if (opt == TCPOPT_EOL)
 478                                 break;
 479                 }
 480                 putchar('>');
 481         }
 482
 483         if (length <= 0)
 484                 return;
 485
 486         /*
 487          * Decode payload if necessary.
 488          */
 489         bp += (tp->th_off * 4);
 490         if (sport == 179 || dport == 179)
 491                 bgp_print(bp, length);
 492         if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
 493                 nbt_tcp_print(bp, length);
 494         return;
 495 bad:
 496         fputs("[bad opt]", stdout);
 497         if (ch != '\0')
 498                 putchar('>');
 499         return;
 500 trunc:
 501         fputs("[|tcp]", stdout);
 502         if (ch != '\0')
 503                 putchar('>');
 504 }
 505