xref: /freebsd/contrib/tcpdump/print-tcp.c (revision 1fb62fb074788ca4713551be09d6569966a3abee)
1 /*	$NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $	*/
2 
3 /*
4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Copyright (c) 1999-2004 The tcpdump.org project
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that: (1) source code distributions
11  * retain the above copyright notice and this paragraph in its entirety, (2)
12  * distributions including binary code include the above copyright notice and
13  * this paragraph in its entirety in the documentation or other materials
14  * provided with the distribution, and (3) all advertising materials mentioning
15  * features or use of this software display the following acknowledgement:
16  * ``This product includes software developed by the University of California,
17  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
18  * the University nor the names of its contributors may be used to endorse
19  * or promote products derived from this software without specific prior
20  * written permission.
21  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
22  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
23  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
24  */
25 
26 #ifndef lint
27 #else
28 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
29 #endif
30 
31 #define NETDISSECT_REWORKED
32 #ifdef HAVE_CONFIG_H
33 #include "config.h"
34 #endif
35 
36 #include <tcpdump-stdinc.h>
37 
38 #include <stdlib.h>
39 #include <string.h>
40 
41 #include "interface.h"
42 #include "addrtoname.h"
43 #include "extract.h"
44 
45 #include "tcp.h"
46 
47 #include "ip.h"
48 #ifdef INET6
49 #include "ip6.h"
50 #endif
51 #include "ipproto.h"
52 #include "rpc_auth.h"
53 #include "rpc_msg.h"
54 
55 #include "nameser.h"
56 
57 #ifdef HAVE_LIBCRYPTO
58 #include <openssl/md5.h>
59 #include <signature.h>
60 
61 static int tcp_verify_signature(netdissect_options *ndo,
62                                 const struct ip *ip, const struct tcphdr *tp,
63                                 const u_char *data, int length, const u_char *rcvsig);
64 #endif
65 
66 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
67 
68 #define MAX_RST_DATA_LEN	30
69 
70 
71 struct tha {
72         struct in_addr src;
73         struct in_addr dst;
74         u_int port;
75 };
76 
77 struct tcp_seq_hash {
78         struct tcp_seq_hash *nxt;
79         struct tha addr;
80         tcp_seq seq;
81         tcp_seq ack;
82 };
83 
84 #ifdef INET6
85 struct tha6 {
86         struct in6_addr src;
87         struct in6_addr dst;
88         u_int port;
89 };
90 
91 struct tcp_seq_hash6 {
92         struct tcp_seq_hash6 *nxt;
93         struct tha6 addr;
94         tcp_seq seq;
95         tcp_seq ack;
96 };
97 #endif
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_hash4[TSEQ_HASHSIZE];
105 #ifdef INET6
106 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
107 #endif
108 
109 static const struct tok tcp_flag_values[] = {
110         { TH_FIN, "F" },
111         { TH_SYN, "S" },
112         { TH_RST, "R" },
113         { TH_PUSH, "P" },
114         { TH_ACK, "." },
115         { TH_URG, "U" },
116         { TH_ECNECHO, "E" },
117         { TH_CWR, "W" },
118         { 0, NULL }
119 };
120 
121 static const struct tok tcp_option_values[] = {
122         { TCPOPT_EOL, "eol" },
123         { TCPOPT_NOP, "nop" },
124         { TCPOPT_MAXSEG, "mss" },
125         { TCPOPT_WSCALE, "wscale" },
126         { TCPOPT_SACKOK, "sackOK" },
127         { TCPOPT_SACK, "sack" },
128         { TCPOPT_ECHO, "echo" },
129         { TCPOPT_ECHOREPLY, "echoreply" },
130         { TCPOPT_TIMESTAMP, "TS" },
131         { TCPOPT_CC, "cc" },
132         { TCPOPT_CCNEW, "ccnew" },
133         { TCPOPT_CCECHO, "" },
134         { TCPOPT_SIGNATURE, "md5" },
135         { TCPOPT_AUTH, "enhanced auth" },
136         { TCPOPT_UTO, "uto" },
137         { TCPOPT_MPTCP, "mptcp" },
138         { TCPOPT_EXPERIMENT2, "exp" },
139         { 0, NULL }
140 };
141 
142 static int
143 tcp_cksum(netdissect_options *ndo,
144           register const struct ip *ip,
145           register const struct tcphdr *tp,
146           register u_int len)
147 {
148 	return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
149 				IPPROTO_TCP);
150 }
151 
152 void
153 tcp_print(netdissect_options *ndo,
154           register const u_char *bp, register u_int length,
155           register const u_char *bp2, int fragmented)
156 {
157         register const struct tcphdr *tp;
158         register const struct ip *ip;
159         register u_char flags;
160         register u_int hlen;
161         register char ch;
162         uint16_t sport, dport, win, urp;
163         uint32_t seq, ack, thseq, thack;
164         u_int utoval;
165         uint16_t magic;
166         register int rev;
167 #ifdef INET6
168         register const struct ip6_hdr *ip6;
169 #endif
170 
171         tp = (struct tcphdr *)bp;
172         ip = (struct ip *)bp2;
173 #ifdef INET6
174         if (IP_V(ip) == 6)
175                 ip6 = (struct ip6_hdr *)bp2;
176         else
177                 ip6 = NULL;
178 #endif /*INET6*/
179         ch = '\0';
180         if (!ND_TTEST(tp->th_dport)) {
181                 ND_PRINT((ndo, "%s > %s: [|tcp]",
182                              ipaddr_string(ndo, &ip->ip_src),
183                              ipaddr_string(ndo, &ip->ip_dst)));
184                 return;
185         }
186 
187         sport = EXTRACT_16BITS(&tp->th_sport);
188         dport = EXTRACT_16BITS(&tp->th_dport);
189 
190         hlen = TH_OFF(tp) * 4;
191 
192 #ifdef INET6
193         if (ip6) {
194                 if (ip6->ip6_nxt == IPPROTO_TCP) {
195                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
196                                      ip6addr_string(ndo, &ip6->ip6_src),
197                                      tcpport_string(sport),
198                                      ip6addr_string(ndo, &ip6->ip6_dst),
199                                      tcpport_string(dport)));
200                 } else {
201                         ND_PRINT((ndo, "%s > %s: ",
202                                      tcpport_string(sport), tcpport_string(dport)));
203                 }
204         } else
205 #endif /*INET6*/
206         {
207                 if (ip->ip_p == IPPROTO_TCP) {
208                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
209                                      ipaddr_string(ndo, &ip->ip_src),
210                                      tcpport_string(sport),
211                                      ipaddr_string(ndo, &ip->ip_dst),
212                                      tcpport_string(dport)));
213                 } else {
214                         ND_PRINT((ndo, "%s > %s: ",
215                                      tcpport_string(sport), tcpport_string(dport)));
216                 }
217         }
218 
219         if (hlen < sizeof(*tp)) {
220                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
221                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
222                 return;
223         }
224 
225         ND_TCHECK(*tp);
226 
227         seq = EXTRACT_32BITS(&tp->th_seq);
228         ack = EXTRACT_32BITS(&tp->th_ack);
229         win = EXTRACT_16BITS(&tp->th_win);
230         urp = EXTRACT_16BITS(&tp->th_urp);
231 
232         if (ndo->ndo_qflag) {
233                 ND_PRINT((ndo, "tcp %d", length - hlen));
234                 if (hlen > length) {
235                         ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
236                                      hlen, length));
237                 }
238                 return;
239         }
240 
241         flags = tp->th_flags;
242         ND_PRINT((ndo, "Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags)));
243 
244         if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
245                 /*
246                  * Find (or record) the initial sequence numbers for
247                  * this conversation.  (we pick an arbitrary
248                  * collating order so there's only one entry for
249                  * both directions).
250                  */
251                 rev = 0;
252 #ifdef INET6
253                 if (ip6) {
254                         register struct tcp_seq_hash6 *th;
255                         struct tcp_seq_hash6 *tcp_seq_hash;
256                         const struct in6_addr *src, *dst;
257                         struct tha6 tha;
258 
259                         tcp_seq_hash = tcp_seq_hash6;
260                         src = &ip6->ip6_src;
261                         dst = &ip6->ip6_dst;
262                         if (sport > dport)
263                                 rev = 1;
264                         else if (sport == dport) {
265                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
266                                         rev = 1;
267                         }
268                         if (rev) {
269                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
270                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
271                                 tha.port = dport << 16 | sport;
272                         } else {
273                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
274                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
275                                 tha.port = sport << 16 | dport;
276                         }
277 
278                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
279                              th->nxt; th = th->nxt)
280                                 if (memcmp((char *)&tha, (char *)&th->addr,
281                                            sizeof(th->addr)) == 0)
282                                         break;
283 
284                         if (!th->nxt || (flags & TH_SYN)) {
285                                 /* didn't find it or new conversation */
286                                 if (th->nxt == NULL) {
287                                         th->nxt = (struct tcp_seq_hash6 *)
288                                                 calloc(1, sizeof(*th));
289                                         if (th->nxt == NULL)
290                                                 error("tcp_print: calloc");
291                                 }
292                                 th->addr = tha;
293                                 if (rev)
294                                         th->ack = seq, th->seq = ack - 1;
295                                 else
296                                         th->seq = seq, th->ack = ack - 1;
297                         } else {
298                                 if (rev)
299                                         seq -= th->ack, ack -= th->seq;
300                                 else
301                                         seq -= th->seq, ack -= th->ack;
302                         }
303 
304                         thseq = th->seq;
305                         thack = th->ack;
306                 } else {
307 #else  /*INET6*/
308                 {
309 #endif /*INET6*/
310                         register struct tcp_seq_hash *th;
311                         struct tcp_seq_hash *tcp_seq_hash;
312                         const struct in_addr *src, *dst;
313                         struct tha tha;
314 
315                         tcp_seq_hash = tcp_seq_hash4;
316                         src = &ip->ip_src;
317                         dst = &ip->ip_dst;
318                         if (sport > dport)
319                                 rev = 1;
320                         else if (sport == dport) {
321                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip->ip_dst) > 0)
322                                         rev = 1;
323                         }
324                         if (rev) {
325                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip->ip_dst);
326                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip->ip_src);
327                                 tha.port = dport << 16 | sport;
328                         } else {
329                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip->ip_dst);
330                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip->ip_src);
331                                 tha.port = sport << 16 | dport;
332                         }
333 
334                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
335                              th->nxt; th = th->nxt)
336                                 if (memcmp((char *)&tha, (char *)&th->addr,
337                                            sizeof(th->addr)) == 0)
338                                         break;
339 
340                         if (!th->nxt || (flags & TH_SYN)) {
341                                 /* didn't find it or new conversation */
342                                 if (th->nxt == NULL) {
343                                         th->nxt = (struct tcp_seq_hash *)
344                                                 calloc(1, sizeof(*th));
345                                         if (th->nxt == NULL)
346                                                 error("tcp_print: calloc");
347                                 }
348                                 th->addr = tha;
349                                 if (rev)
350                                         th->ack = seq, th->seq = ack - 1;
351                                 else
352                                         th->seq = seq, th->ack = ack - 1;
353                         } else {
354                                 if (rev)
355                                         seq -= th->ack, ack -= th->seq;
356                                 else
357                                         seq -= th->seq, ack -= th->ack;
358                         }
359 
360                         thseq = th->seq;
361                         thack = th->ack;
362                 }
363         } else {
364                 /*fool gcc*/
365                 thseq = thack = rev = 0;
366         }
367         if (hlen > length) {
368                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
369                              hlen, length));
370                 return;
371         }
372 
373         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
374                 /* Check the checksum, if possible. */
375                 uint16_t sum, tcp_sum;
376 
377                 if (IP_V(ip) == 4) {
378                         if (ND_TTEST2(tp->th_sport, length)) {
379                                 sum = tcp_cksum(ndo, ip, tp, length);
380                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
381 
382                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
383                                 if (sum != 0)
384                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
385                                             in_cksum_shouldbe(tcp_sum, sum)));
386                                 else
387                                         ND_PRINT((ndo, " (correct)"));
388                         }
389                 }
390 #ifdef INET6
391                 else if (IP_V(ip) == 6 && ip6->ip6_plen) {
392                         if (ND_TTEST2(tp->th_sport, length)) {
393                                 sum = nextproto6_cksum(ip6, (const uint8_t *)tp,
394 							length, length, IPPROTO_TCP);
395                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
396 
397                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
398                                 if (sum != 0)
399                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
400                                             in_cksum_shouldbe(tcp_sum, sum)));
401                                 else
402                                         ND_PRINT((ndo, " (correct)"));
403 
404                         }
405                 }
406 #endif
407         }
408 
409         length -= hlen;
410         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
411                 ND_PRINT((ndo, ", seq %u", seq));
412 
413                 if (length > 0) {
414                         ND_PRINT((ndo, ":%u", seq + length));
415                 }
416         }
417 
418         if (flags & TH_ACK) {
419                 ND_PRINT((ndo, ", ack %u", ack));
420         }
421 
422         ND_PRINT((ndo, ", win %d", win));
423 
424         if (flags & TH_URG)
425                 ND_PRINT((ndo, ", urg %d", urp));
426         /*
427          * Handle any options.
428          */
429         if (hlen > sizeof(*tp)) {
430                 register const u_char *cp;
431                 register u_int i, opt, datalen;
432                 register u_int len;
433 
434                 hlen -= sizeof(*tp);
435                 cp = (const u_char *)tp + sizeof(*tp);
436                 ND_PRINT((ndo, ", options ["));
437                 while (hlen > 0) {
438                         if (ch != '\0')
439                                 ND_PRINT((ndo, "%c", ch));
440                         ND_TCHECK(*cp);
441                         opt = *cp++;
442                         if (ZEROLENOPT(opt))
443                                 len = 1;
444                         else {
445                                 ND_TCHECK(*cp);
446                                 len = *cp++;	/* total including type, len */
447                                 if (len < 2 || len > hlen)
448                                         goto bad;
449                                 --hlen;		/* account for length byte */
450                         }
451                         --hlen;			/* account for type byte */
452                         datalen = 0;
453 
454 /* Bail if "l" bytes of data are not left or were not captured  */
455 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
456 
457 
458                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
459 
460                         switch (opt) {
461 
462                         case TCPOPT_MAXSEG:
463                                 datalen = 2;
464                                 LENCHECK(datalen);
465                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
466                                 break;
467 
468                         case TCPOPT_WSCALE:
469                                 datalen = 1;
470                                 LENCHECK(datalen);
471                                 ND_PRINT((ndo, " %u", *cp));
472                                 break;
473 
474                         case TCPOPT_SACK:
475                                 datalen = len - 2;
476                                 if (datalen % 8 != 0) {
477                                         ND_PRINT((ndo, "malformed sack"));
478                                 } else {
479                                         uint32_t s, e;
480 
481                                         ND_PRINT((ndo, " %d ", datalen / 8));
482                                         for (i = 0; i < datalen; i += 8) {
483                                                 LENCHECK(i + 4);
484                                                 s = EXTRACT_32BITS(cp + i);
485                                                 LENCHECK(i + 8);
486                                                 e = EXTRACT_32BITS(cp + i + 4);
487                                                 if (rev) {
488                                                         s -= thseq;
489                                                         e -= thseq;
490                                                 } else {
491                                                         s -= thack;
492                                                         e -= thack;
493                                                 }
494                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
495                                         }
496                                 }
497                                 break;
498 
499                         case TCPOPT_CC:
500                         case TCPOPT_CCNEW:
501                         case TCPOPT_CCECHO:
502                         case TCPOPT_ECHO:
503                         case TCPOPT_ECHOREPLY:
504 
505                                 /*
506                                  * those options share their semantics.
507                                  * fall through
508                                  */
509                                 datalen = 4;
510                                 LENCHECK(datalen);
511                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
512                                 break;
513 
514                         case TCPOPT_TIMESTAMP:
515                                 datalen = 8;
516                                 LENCHECK(datalen);
517                                 ND_PRINT((ndo, " val %u ecr %u",
518                                              EXTRACT_32BITS(cp),
519                                              EXTRACT_32BITS(cp + 4)));
520                                 break;
521 
522                         case TCPOPT_SIGNATURE:
523                                 datalen = TCP_SIGLEN;
524                                 LENCHECK(datalen);
525 #ifdef HAVE_LIBCRYPTO
526                                 switch (tcp_verify_signature(ndo, ip, tp,
527                                                              bp + TH_OFF(tp) * 4, length, cp)) {
528 
529                                 case SIGNATURE_VALID:
530                                         ND_PRINT((ndo, "valid"));
531                                         break;
532 
533                                 case SIGNATURE_INVALID:
534                                         ND_PRINT((ndo, "invalid"));
535                                         break;
536 
537                                 case CANT_CHECK_SIGNATURE:
538                                         ND_PRINT((ndo, "can't check - "));
539                                         for (i = 0; i < TCP_SIGLEN; ++i)
540                                                 ND_PRINT((ndo, "%02x", cp[i]));
541                                         break;
542                                 }
543 #else
544                                 for (i = 0; i < TCP_SIGLEN; ++i)
545                                         ND_PRINT((ndo, "%02x", cp[i]));
546 #endif
547                                 break;
548 
549                         case TCPOPT_AUTH:
550                                 ND_PRINT((ndo, "keyid %d", *cp++));
551                                 datalen = len - 3;
552                                 for (i = 0; i < datalen; ++i) {
553                                         LENCHECK(i);
554                                         ND_PRINT((ndo, "%02x", cp[i]));
555                                 }
556                                 break;
557 
558 
559                         case TCPOPT_EOL:
560                         case TCPOPT_NOP:
561                         case TCPOPT_SACKOK:
562                                 /*
563                                  * Nothing interesting.
564                                  * fall through
565                                  */
566                                 break;
567 
568                         case TCPOPT_UTO:
569                                 datalen = 2;
570                                 LENCHECK(datalen);
571                                 utoval = EXTRACT_16BITS(cp);
572                                 ND_PRINT((ndo, "0x%x", utoval));
573                                 if (utoval & 0x0001)
574                                         utoval = (utoval >> 1) * 60;
575                                 else
576                                         utoval >>= 1;
577                                 ND_PRINT((ndo, " %u", utoval));
578                                 break;
579 
580                         case TCPOPT_MPTCP:
581                                 datalen = len - 2;
582                                 LENCHECK(datalen);
583                                 if (!mptcp_print(ndo, cp-2, len, flags))
584                                         goto bad;
585                                 break;
586 
587                         case TCPOPT_EXPERIMENT2:
588                                 datalen = len - 2;
589                                 LENCHECK(datalen);
590                                 if (datalen < 2)
591                                         goto bad;
592                                 /* RFC6994 */
593                                 magic = EXTRACT_16BITS(cp);
594                                 ND_PRINT((ndo, "-"));
595 
596                                 switch(magic) {
597 
598                                 case 0xf989:
599                                         /* TCP Fast Open: RFC 7413 */
600                                         if (datalen == 2) {
601                                                 /* Fast Open Cookie Request */
602                                                 ND_PRINT((ndo, "tfo cookiereq"));
603                                         } else {
604                                                 /* Fast Open Cookie */
605                                                 if (datalen % 2 != 0 || datalen < 6 || datalen > 18) {
606                                                         ND_PRINT((ndo, "tfo malformed"));
607                                                 } else {
608                                                         ND_PRINT((ndo, "tfo cookie "));
609                                                         for (i = 2; i < datalen; ++i)
610                                                                 ND_PRINT((ndo, "%02x", cp[i]));
611                                                 }
612                                         }
613                                         break;
614 
615                                 default:
616                                         /* Unknown magic number */
617                                         ND_PRINT((ndo, "%04x", magic));
618                                         break;
619                                 }
620                                 break;
621 
622                         default:
623                                 datalen = len - 2;
624                                 if (datalen)
625                                         ND_PRINT((ndo, " 0x"));
626                                 for (i = 0; i < datalen; ++i) {
627                                         LENCHECK(i);
628                                         ND_PRINT((ndo, "%02x", cp[i]));
629                                 }
630                                 break;
631                         }
632 
633                         /* Account for data printed */
634                         cp += datalen;
635                         hlen -= datalen;
636 
637                         /* Check specification against observed length */
638                         ++datalen;			/* option octet */
639                         if (!ZEROLENOPT(opt))
640                                 ++datalen;		/* size octet */
641                         if (datalen != len)
642                                 ND_PRINT((ndo, "[len %d]", len));
643                         ch = ',';
644                         if (opt == TCPOPT_EOL)
645                                 break;
646                 }
647                 ND_PRINT((ndo, "]"));
648         }
649 
650         /*
651          * Print length field before crawling down the stack.
652          */
653         ND_PRINT((ndo, ", length %u", length));
654 
655         if (length <= 0)
656                 return;
657 
658         /*
659          * Decode payload if necessary.
660          */
661         bp += TH_OFF(tp) * 4;
662         if ((flags & TH_RST) && ndo->ndo_vflag) {
663                 print_tcp_rst_data(ndo, bp, length);
664                 return;
665         }
666 
667         if (ndo->ndo_packettype) {
668                 switch (ndo->ndo_packettype) {
669                 case PT_ZMTP1:
670                         zmtp1_print(ndo, bp, length);
671                         break;
672                 }
673                 return;
674         }
675 
676         if (sport == TELNET_PORT || dport == TELNET_PORT) {
677                 telnet_print(ndo, bp, length);
678         } else if (sport == SMTP_PORT || dport == SMTP_PORT) {
679                 ND_PRINT((ndo, ": "));
680                 smtp_print(ndo, bp, length);
681         } else if (sport == BGP_PORT || dport == BGP_PORT)
682                 bgp_print(ndo, bp, length);
683         else if (sport == PPTP_PORT || dport == PPTP_PORT)
684                 pptp_print(ndo, bp);
685 #ifdef TCPDUMP_DO_SMB
686         else if (sport == NETBIOS_SSN_PORT || dport == NETBIOS_SSN_PORT)
687                 nbt_tcp_print(ndo, bp, length);
688 	else if (sport == SMB_PORT || dport == SMB_PORT)
689 		smb_tcp_print(ndo, bp, length);
690 #endif
691         else if (sport == BEEP_PORT || dport == BEEP_PORT)
692                 beep_print(ndo, bp, length);
693         else if (sport == OPENFLOW_PORT_OLD || dport == OPENFLOW_PORT_OLD ||
694                  sport == OPENFLOW_PORT_IANA || dport == OPENFLOW_PORT_IANA)
695                 openflow_print(ndo, bp, length);
696         else if (sport == FTP_PORT || dport == FTP_PORT) {
697                 ND_PRINT((ndo, ": "));
698                 ftp_print(ndo, bp, length);
699         } else if (sport == HTTP_PORT || dport == HTTP_PORT ||
700             sport == HTTP_PORT_ALT || dport == HTTP_PORT_ALT) {
701                 ND_PRINT((ndo, ": "));
702                 http_print(ndo, bp, length);
703         } else if (sport == RTSP_PORT || dport == RTSP_PORT ||
704             sport == RTSP_PORT_ALT || dport == RTSP_PORT_ALT) {
705                 ND_PRINT((ndo, ": "));
706                 rtsp_print(ndo, bp, length);
707         } else if (length > 2 &&
708                  (sport == NAMESERVER_PORT || dport == NAMESERVER_PORT ||
709                   sport == MULTICASTDNS_PORT || dport == MULTICASTDNS_PORT)) {
710                 /*
711                  * TCP DNS query has 2byte length at the head.
712                  * XXX packet could be unaligned, it can go strange
713                  */
714                 ns_print(ndo, bp + 2, length - 2, 0);
715         } else if (sport == MSDP_PORT || dport == MSDP_PORT) {
716                 msdp_print(ndo, bp, length);
717         } else if (sport == RPKI_RTR_PORT || dport == RPKI_RTR_PORT) {
718                 rpki_rtr_print(ndo, bp, length);
719         }
720         else if (length > 0 && (sport == LDP_PORT || dport == LDP_PORT)) {
721                 ldp_print(ndo, bp, length);
722         }
723         else if ((sport == NFS_PORT || dport == NFS_PORT) &&
724                  length >= 4 && ND_TTEST2(*bp, 4)) {
725                 /*
726                  * If data present, header length valid, and NFS port used,
727                  * assume NFS.
728                  * Pass offset of data plus 4 bytes for RPC TCP msg length
729                  * to NFS print routines.
730                  */
731                 uint32_t fraglen;
732                 register struct sunrpc_msg *rp;
733                 enum sunrpc_msg_type direction;
734 
735                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
736                 if (fraglen > (length) - 4)
737                         fraglen = (length) - 4;
738                 rp = (struct sunrpc_msg *)(bp + 4);
739                 if (ND_TTEST(rp->rm_direction)) {
740                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
741                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
742                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
743                                 nfsreq_print_noaddr(ndo, (u_char *)rp, fraglen, (u_char *)ip);
744                                 return;
745                         }
746                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
747                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
748                                 nfsreply_print_noaddr(ndo, (u_char *)rp, fraglen, (u_char *)ip);
749                                 return;
750                         }
751                 }
752         }
753 
754         return;
755  bad:
756         ND_PRINT((ndo, "[bad opt]"));
757         if (ch != '\0')
758                 ND_PRINT((ndo, ">"));
759         return;
760  trunc:
761         ND_PRINT((ndo, "[|tcp]"));
762         if (ch != '\0')
763                 ND_PRINT((ndo, ">"));
764 }
765 
766 /*
767  * RFC1122 says the following on data in RST segments:
768  *
769  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
770  *
771  *            A TCP SHOULD allow a received RST segment to include data.
772  *
773  *            DISCUSSION
774  *                 It has been suggested that a RST segment could contain
775  *                 ASCII text that encoded and explained the cause of the
776  *                 RST.  No standard has yet been established for such
777  *                 data.
778  *
779  */
780 
781 static void
782 print_tcp_rst_data(netdissect_options *ndo,
783                    register const u_char *sp, u_int length)
784 {
785         int c;
786 
787         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
788         if (length > MAX_RST_DATA_LEN) {
789                 length = MAX_RST_DATA_LEN;	/* can use -X for longer */
790                 ND_PRINT((ndo, "+"));			/* indicate we truncate */
791         }
792         ND_PRINT((ndo, " "));
793         while (length-- && sp <= ndo->ndo_snapend) {
794                 c = *sp++;
795                 safeputchar(ndo, c);
796         }
797         ND_PRINT((ndo, "]"));
798 }
799 
800 #ifdef HAVE_LIBCRYPTO
801 USES_APPLE_DEPRECATED_API
802 static int
803 tcp_verify_signature(netdissect_options *ndo,
804                      const struct ip *ip, const struct tcphdr *tp,
805                      const u_char *data, int length, const u_char *rcvsig)
806 {
807         struct tcphdr tp1;
808         u_char sig[TCP_SIGLEN];
809         char zero_proto = 0;
810         MD5_CTX ctx;
811         uint16_t savecsum, tlen;
812 #ifdef INET6
813         struct ip6_hdr *ip6;
814         uint32_t len32;
815         uint8_t nxt;
816 #endif
817 
818 	if (data + length > ndo->ndo_snapend) {
819 		ND_PRINT((ndo, "snaplen too short, "));
820 		return (CANT_CHECK_SIGNATURE);
821 	}
822 
823         tp1 = *tp;
824 
825         if (ndo->ndo_sigsecret == NULL) {
826 		ND_PRINT((ndo, "shared secret not supplied with -M, "));
827                 return (CANT_CHECK_SIGNATURE);
828         }
829 
830         MD5_Init(&ctx);
831         /*
832          * Step 1: Update MD5 hash with IP pseudo-header.
833          */
834         if (IP_V(ip) == 4) {
835                 MD5_Update(&ctx, (char *)&ip->ip_src, sizeof(ip->ip_src));
836                 MD5_Update(&ctx, (char *)&ip->ip_dst, sizeof(ip->ip_dst));
837                 MD5_Update(&ctx, (char *)&zero_proto, sizeof(zero_proto));
838                 MD5_Update(&ctx, (char *)&ip->ip_p, sizeof(ip->ip_p));
839                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
840                 tlen = htons(tlen);
841                 MD5_Update(&ctx, (char *)&tlen, sizeof(tlen));
842 #ifdef INET6
843         } else if (IP_V(ip) == 6) {
844                 ip6 = (struct ip6_hdr *)ip;
845                 MD5_Update(&ctx, (char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
846                 MD5_Update(&ctx, (char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
847                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
848                 MD5_Update(&ctx, (char *)&len32, sizeof(len32));
849                 nxt = 0;
850                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
851                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
852                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
853                 nxt = IPPROTO_TCP;
854                 MD5_Update(&ctx, (char *)&nxt, sizeof(nxt));
855 #endif
856         } else {
857 #ifdef INET6
858 		ND_PRINT((ndo, "IP version not 4 or 6, "));
859 #else
860 		ND_PRINT((ndo, "IP version not 4, "));
861 #endif
862                 return (CANT_CHECK_SIGNATURE);
863         }
864 
865         /*
866          * Step 2: Update MD5 hash with TCP header, excluding options.
867          * The TCP checksum must be set to zero.
868          */
869         savecsum = tp1.th_sum;
870         tp1.th_sum = 0;
871         MD5_Update(&ctx, (char *)&tp1, sizeof(struct tcphdr));
872         tp1.th_sum = savecsum;
873         /*
874          * Step 3: Update MD5 hash with TCP segment data, if present.
875          */
876         if (length > 0)
877                 MD5_Update(&ctx, data, length);
878         /*
879          * Step 4: Update MD5 hash with shared secret.
880          */
881         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
882         MD5_Final(sig, &ctx);
883 
884         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
885                 return (SIGNATURE_VALID);
886         else
887                 return (SIGNATURE_INVALID);
888 }
889 USES_APPLE_RST
890 #endif /* HAVE_LIBCRYPTO */
891 
892 /*
893  * Local Variables:
894  * c-style: whitesmith
895  * c-basic-offset: 8
896  * End:
897  */
898