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 1.57 1999-10-30 05:11:21 itojun 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;
 118 #ifdef INET6
 119         register const struct ip6_hdr *ip6;
 120 #endif
 121
 122         tp = (struct tcphdr *)bp;
 123         ip = (struct ip *)bp2;
 124 #ifdef INET6
 125         if (ip->ip_v == 6)
 126                 ip6 = (struct ip6_hdr *)bp2;
 127         else
 128                 ip6 = NULL;
 129 #endif /*INET6*/
 130         ch = '\0';
 131         TCHECK(*tp);
 132         if (length < sizeof(*tp)) {
 133                 (void)printf("truncated-tcp %d", length);
 134                 return;
 135         }
 136
 137         sport = ntohs(tp->th_sport);
 138         dport = ntohs(tp->th_dport);
 139         seq = ntohl(tp->th_seq);
 140         ack = ntohl(tp->th_ack);
 141         win = ntohs(tp->th_win);
 142         urp = ntohs(tp->th_urp);
 143
 144 #ifdef INET6
 145         if (ip6) {
 146                 if (ip6->ip6_nxt == IPPROTO_TCP) {
 147                         (void)printf("%s.%s > %s.%s: ",
 148                                 ip6addr_string(&ip6->ip6_src),
 149                                 tcpport_string(sport),
 150                                 ip6addr_string(&ip6->ip6_dst),
 151                                 tcpport_string(dport));
 152                 } else {
 153                         (void)printf("%s > %s: ",
 154                                 tcpport_string(sport), tcpport_string(dport));
 155                 }
 156         } else
 157 #endif /*INET6*/
 158         {
 159                 if (ip->ip_p == IPPROTO_TCP) {
 160                         (void)printf("%s.%s > %s.%s: ",
 161                                 ipaddr_string(&ip->ip_src),
 162                                 tcpport_string(sport),
 163                                 ipaddr_string(&ip->ip_dst),
 164                                 tcpport_string(dport));
 165                 } else {
 166                         (void)printf("%s > %s: ",
 167                                 tcpport_string(sport), tcpport_string(dport));
 168                 }
 169         }
 170
 171         if (qflag) {
 172                 (void)printf("tcp %d", length - tp->th_off * 4);
 173                 return;
 174         }
 175 #ifdef TH_ECN
 176         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH|TH_ECN)) {
 177 #else
 178         if ((flags = tp->th_flags) & (TH_SYN|TH_FIN|TH_RST|TH_PUSH)) {
 179 #endif
 180                 if (flags & TH_SYN)
 181                         putchar('S');
 182                 if (flags & TH_FIN)
 183                         putchar('F');
 184                 if (flags & TH_RST)
 185                         putchar('R');
 186                 if (flags & TH_PUSH)
 187                         putchar('P');
 188 #ifdef TH_ECN
 189                 if (flags & TH_ECN)
 190                         putchar('C');
 191 #endif
 192         } else
 193                 putchar('.');
 194
 195         if (!Sflag && (flags & TH_ACK)) {
 196                 register struct tcp_seq_hash *th;
 197                 register int rev;
 198                 struct tha tha;
 199                 /*
 200                  * Find (or record) the initial sequence numbers for
 201                  * this conversation.  (we pick an arbitrary
 202                  * collating order so there's only one entry for
 203                  * both directions).
 204                  */
 205 #ifdef INET6
 206                 bzero(&tha, sizeof(tha));
 207                 rev = 0;
 208                 if (ip6) {
 209                         if (sport > dport) {
 210                                 rev = 1;
 211                         } else if (sport == dport) {
 212                             int i;
 213
 214                             for (i = 0; i < 4; i++) {
 215                                 if (((u_int32_t *)(&ip6->ip6_src))[i] >
 216                                     ((u_int32_t *)(&ip6->ip6_dst))[i]) {
 217                                         rev = 1;
 218                                         break;
 219                                 }
 220                             }
 221                         }
 222                         if (rev) {
 223                                 tha.src = ip6->ip6_dst;
 224                                 tha.dst = ip6->ip6_src;
 225                                 tha.port = dport << 16 | sport;
 226                         } else {
 227                                 tha.dst = ip6->ip6_dst;
 228                                 tha.src = ip6->ip6_src;
 229                                 tha.port = sport << 16 | dport;
 230                         }
 231                 } else {
 232                         if (sport > dport ||
 233                             (sport == dport &&
 234                              ip->ip_src.s_addr > ip->ip_dst.s_addr)) {
 235                                 rev = 1;
 236                         }
 237                         if (rev) {
 238                                 *(struct in_addr *)&tha.src = ip->ip_dst;
 239                                 *(struct in_addr *)&tha.dst = ip->ip_src;
 240                                 tha.port = dport << 16 | sport;
 241                         } else {
 242                                 *(struct in_addr *)&tha.dst = ip->ip_dst;
 243                                 *(struct in_addr *)&tha.src = ip->ip_src;
 244                                 tha.port = sport << 16 | dport;
 245                         }
 246                 }
 247 #else
 248                 if (sport < dport ||
 249                     (sport == dport &&
 250                      ip->ip_src.s_addr < ip->ip_dst.s_addr)) {
 251                         tha.src = ip->ip_src, tha.dst = ip->ip_dst;
 252                         tha.port = sport << 16 | dport;
 253                         rev = 0;
 254                 } else {
 255                         tha.src = ip->ip_dst, tha.dst = ip->ip_src;
 256                         tha.port = dport << 16 | sport;
 257                         rev = 1;
 258                 }
 259 #endif
 260
 261                 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
 262                      th->nxt; th = th->nxt)
 263                         if (!memcmp((char *)&tha, (char *)&th->addr,
 264                                   sizeof(th->addr)))
 265                                 break;
 266
 267                 if (!th->nxt || flags & TH_SYN) {
 268                         /* didn't find it or new conversation */
 269                         if (th->nxt == NULL) {
 270                                 th->nxt = (struct tcp_seq_hash *)
 271                                         calloc(1, sizeof(*th));
 272                                 if (th->nxt == NULL)
 273                                         error("tcp_print: calloc");
 274                         }
 275                         th->addr = tha;
 276                         if (rev)
 277                                 th->ack = seq, th->seq = ack - 1;
 278                         else
 279                                 th->seq = seq, th->ack = ack - 1;
 280                 } else {
 281                         if (rev)
 282                                 seq -= th->ack, ack -= th->seq;
 283                         else
 284                                 seq -= th->seq, ack -= th->ack;
 285                 }
 286         }
 287         hlen = tp->th_off * 4;
 288         if (hlen > length) {
 289                 (void)printf(" [bad hdr length]");
 290                 return;
 291         }
 292         length -= hlen;
 293         if (length > 0 || flags & (TH_SYN | TH_FIN | TH_RST))
 294                 (void)printf(" %u:%u(%d)", seq, seq + length, length);
 295         if (flags & TH_ACK)
 296                 (void)printf(" ack %u", ack);
 297
 298         (void)printf(" win %d", win);
 299
 300         if (flags & TH_URG)
 301                 (void)printf(" urg %d", urp);
 302         /*
 303          * Handle any options.
 304          */
 305         if ((hlen -= sizeof(*tp)) > 0) {
 306                 register const u_char *cp;
 307                 register int i, opt, len, datalen;
 308
 309                 cp = (const u_char *)tp + sizeof(*tp);
 310                 putchar(' ');
 311                 ch = '<';
 312                 while (hlen > 0) {
 313                         putchar(ch);
 314                         TCHECK(*cp);
 315                         opt = *cp++;
 316                         if (ZEROLENOPT(opt))
 317                                 len = 1;
 318                         else {
 319                                 TCHECK(*cp);
 320                                 len = *cp++;    /* total including type, len */
 321                                 if (len < 2 || len > hlen)
 322                                         goto bad;
 323                                 --hlen;         /* account for length byte */
 324                         }
 325                         --hlen;                 /* account for type byte */
 326                         datalen = 0;
 327
 328 /* Bail if "l" bytes of data are not left or were not captured  */
 329 #define LENCHECK(l) { if ((l) > hlen) goto bad; TCHECK2(*cp, l); }
 330
 331                         switch (opt) {
 332
 333                         case TCPOPT_MAXSEG:
 334                                 (void)printf("mss");
 335                                 datalen = 2;
 336                                 LENCHECK(datalen);
 337                                 (void)printf(" %u", EXTRACT_16BITS(cp));
 338
 339                                 break;
 340
 341                         case TCPOPT_EOL:
 342                                 (void)printf("eol");
 343                                 break;
 344
 345                         case TCPOPT_NOP:
 346                                 (void)printf("nop");
 347                                 break;
 348
 349                         case TCPOPT_WSCALE:
 350                                 (void)printf("wscale");
 351                                 datalen = 1;
 352                                 LENCHECK(datalen);
 353                                 (void)printf(" %u", *cp);
 354                                 break;
 355
 356                         case TCPOPT_SACKOK:
 357                                 (void)printf("sackOK");
 358                                 break;
 359
 360                         case TCPOPT_SACK:
 361                                 (void)printf("sack");
 362                                 datalen = len - 2;
 363                                 for (i = 0; i < datalen; i += 4) {
 364                                         LENCHECK(i + 4);
 365                                         /* block-size@relative-origin */
 366                                         (void)printf(" %u@%u",
 367                                             EXTRACT_16BITS(cp + i + 2),
 368                                             EXTRACT_16BITS(cp + i));
 369                                 }
 370                                 if (datalen % 4)
 371                                         (void)printf("[len %d]", len);
 372                                 break;
 373
 374                         case TCPOPT_ECHO:
 375                                 (void)printf("echo");
 376                                 datalen = 4;
 377                                 LENCHECK(datalen);
 378                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 379                                 break;
 380
 381                         case TCPOPT_ECHOREPLY:
 382                                 (void)printf("echoreply");
 383                                 datalen = 4;
 384                                 LENCHECK(datalen);
 385                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 386                                 break;
 387
 388                         case TCPOPT_TIMESTAMP:
 389                                 (void)printf("timestamp");
 390                                 datalen = 8;
 391                                 LENCHECK(4);
 392                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 393                                 LENCHECK(datalen);
 394                                 (void)printf(" %u", EXTRACT_32BITS(cp + 4));
 395                                 break;
 396
 397                         case TCPOPT_CC:
 398                                 (void)printf("cc");
 399                                 datalen = 4;
 400                                 LENCHECK(datalen);
 401                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 402                                 break;
 403
 404                         case TCPOPT_CCNEW:
 405                                 (void)printf("ccnew");
 406                                 datalen = 4;
 407                                 LENCHECK(datalen);
 408                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 409                                 break;
 410
 411                         case TCPOPT_CCECHO:
 412                                 (void)printf("ccecho");
 413                                 datalen = 4;
 414                                 LENCHECK(datalen);
 415                                 (void)printf(" %u", EXTRACT_32BITS(cp));
 416                                 break;
 417
 418                         default:
 419                                 (void)printf("opt-%d:", opt);
 420                                 datalen = len - 2;
 421                                 for (i = 0; i < datalen; ++i) {
 422                                         LENCHECK(i);
 423                                         (void)printf("%02x", cp[i]);
 424                                 }
 425                                 break;
 426                         }
 427
 428                         /* Account for data printed */
 429                         cp += datalen;
 430                         hlen -= datalen;
 431
 432                         /* Check specification against observed length */
 433                         ++datalen;                      /* option octet */
 434                         if (!ZEROLENOPT(opt))
 435                                 ++datalen;              /* size octet */
 436                         if (datalen != len)
 437                                 (void)printf("[len %d]", len);
 438                         ch = ',';
 439                         if (opt == TCPOPT_EOL)
 440                                 break;
 441                 }
 442                 putchar('>');
 443         }
 444
 445         if (length <= 0)
 446                 return;
 447
 448         /*
 449          * Decode payload if necessary.
 450          */
 451         bp += (tp->th_off * 4);
 452         if (sport == 179 || dport == 179)
 453                 bgp_print(bp, length);
 454         return;
 455 bad:
 456         fputs("[bad opt]", stdout);
 457         if (ch != '\0')
 458                 putchar('>');
 459         return;
 460 trunc:
 461         fputs("[|tcp]", stdout);
 462         if (ch != '\0')
 463                 putchar('>');
 464 }
 465