xref: /freebsd/contrib/tcpdump/print-tcp.c (revision b0d29bc47dba79f6f38e67eabadfb4b32ffd9390)
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 /* \summary: TCP printer */
27 
28 #ifndef lint
29 #else
30 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
31 #endif
32 
33 #ifdef HAVE_CONFIG_H
34 #include "config.h"
35 #endif
36 
37 #include <netdissect-stdinc.h>
38 
39 #include <stdlib.h>
40 #include <string.h>
41 
42 #include "netdissect.h"
43 #include "addrtoname.h"
44 #include "extract.h"
45 
46 #include "tcp.h"
47 
48 #include "ip.h"
49 #include "ip6.h"
50 #include "ipproto.h"
51 #include "rpc_auth.h"
52 #include "rpc_msg.h"
53 
54 #ifdef HAVE_LIBCRYPTO
55 #include <openssl/md5.h>
56 #include "signature.h"
57 
58 static int tcp_verify_signature(netdissect_options *ndo,
59                                 const struct ip *ip, const struct tcphdr *tp,
60                                 const u_char *data, int length, const u_char *rcvsig);
61 #endif
62 
63 static void print_tcp_rst_data(netdissect_options *, register const u_char *sp, u_int length);
64 static void print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
65                                       u_int datalen, int exp);
66 
67 #define MAX_RST_DATA_LEN	30
68 
69 
70 struct tha {
71         struct in_addr src;
72         struct in_addr dst;
73         u_int port;
74 };
75 
76 struct tcp_seq_hash {
77         struct tcp_seq_hash *nxt;
78         struct tha addr;
79         tcp_seq seq;
80         tcp_seq ack;
81 };
82 
83 struct tha6 {
84         struct in6_addr src;
85         struct in6_addr dst;
86         u_int port;
87 };
88 
89 struct tcp_seq_hash6 {
90         struct tcp_seq_hash6 *nxt;
91         struct tha6 addr;
92         tcp_seq seq;
93         tcp_seq ack;
94 };
95 
96 #define TSEQ_HASHSIZE 919
97 
98 /* These tcp optinos do not have the size octet */
99 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
100 
101 static struct tcp_seq_hash tcp_seq_hash4[TSEQ_HASHSIZE];
102 static struct tcp_seq_hash6 tcp_seq_hash6[TSEQ_HASHSIZE];
103 
104 static const struct tok tcp_flag_values[] = {
105         { TH_FIN, "F" },
106         { TH_SYN, "S" },
107         { TH_RST, "R" },
108         { TH_PUSH, "P" },
109         { TH_ACK, "." },
110         { TH_URG, "U" },
111         { TH_ECNECHO, "E" },
112         { TH_CWR, "W" },
113         { 0, NULL }
114 };
115 
116 static const struct tok tcp_option_values[] = {
117         { TCPOPT_EOL, "eol" },
118         { TCPOPT_NOP, "nop" },
119         { TCPOPT_MAXSEG, "mss" },
120         { TCPOPT_WSCALE, "wscale" },
121         { TCPOPT_SACKOK, "sackOK" },
122         { TCPOPT_SACK, "sack" },
123         { TCPOPT_ECHO, "echo" },
124         { TCPOPT_ECHOREPLY, "echoreply" },
125         { TCPOPT_TIMESTAMP, "TS" },
126         { TCPOPT_CC, "cc" },
127         { TCPOPT_CCNEW, "ccnew" },
128         { TCPOPT_CCECHO, "" },
129         { TCPOPT_SIGNATURE, "md5" },
130         { TCPOPT_SCPS, "scps" },
131         { TCPOPT_UTO, "uto" },
132         { TCPOPT_TCPAO, "tcp-ao" },
133         { TCPOPT_MPTCP, "mptcp" },
134         { TCPOPT_FASTOPEN, "tfo" },
135         { TCPOPT_EXPERIMENT2, "exp" },
136         { 0, NULL }
137 };
138 
139 static int
140 tcp_cksum(netdissect_options *ndo,
141           register const struct ip *ip,
142           register const struct tcphdr *tp,
143           register u_int len)
144 {
145 	return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
146 				IPPROTO_TCP);
147 }
148 
149 static int
150 tcp6_cksum(netdissect_options *ndo,
151            register const struct ip6_hdr *ip6,
152            register const struct tcphdr *tp,
153            register u_int len)
154 {
155 	return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
156 				IPPROTO_TCP);
157 }
158 
159 void
160 tcp_print(netdissect_options *ndo,
161           register const u_char *bp, register u_int length,
162           register const u_char *bp2, int fragmented)
163 {
164         register const struct tcphdr *tp;
165         register const struct ip *ip;
166         register u_char flags;
167         register u_int hlen;
168         register char ch;
169         uint16_t sport, dport, win, urp;
170         uint32_t seq, ack, thseq, thack;
171         u_int utoval;
172         uint16_t magic;
173         register int rev;
174         register const struct ip6_hdr *ip6;
175 
176         tp = (const struct tcphdr *)bp;
177         ip = (const struct ip *)bp2;
178         if (IP_V(ip) == 6)
179                 ip6 = (const struct ip6_hdr *)bp2;
180         else
181                 ip6 = NULL;
182         ch = '\0';
183         if (!ND_TTEST(tp->th_dport)) {
184                 ND_PRINT((ndo, "%s > %s: [|tcp]",
185                              ipaddr_string(ndo, &ip->ip_src),
186                              ipaddr_string(ndo, &ip->ip_dst)));
187                 return;
188         }
189 
190         sport = EXTRACT_16BITS(&tp->th_sport);
191         dport = EXTRACT_16BITS(&tp->th_dport);
192 
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(ndo, sport),
198                                      ip6addr_string(ndo, &ip6->ip6_dst),
199                                      tcpport_string(ndo, dport)));
200                 } else {
201                         ND_PRINT((ndo, "%s > %s: ",
202                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
203                 }
204         } else {
205                 if (ip->ip_p == IPPROTO_TCP) {
206                         ND_PRINT((ndo, "%s.%s > %s.%s: ",
207                                      ipaddr_string(ndo, &ip->ip_src),
208                                      tcpport_string(ndo, sport),
209                                      ipaddr_string(ndo, &ip->ip_dst),
210                                      tcpport_string(ndo, dport)));
211                 } else {
212                         ND_PRINT((ndo, "%s > %s: ",
213                                      tcpport_string(ndo, sport), tcpport_string(ndo, dport)));
214                 }
215         }
216 
217         ND_TCHECK(*tp);
218 
219         hlen = TH_OFF(tp) * 4;
220 
221         if (hlen < sizeof(*tp)) {
222                 ND_PRINT((ndo, " tcp %d [bad hdr length %u - too short, < %lu]",
223                              length - hlen, hlen, (unsigned long)sizeof(*tp)));
224                 return;
225         }
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                 if (ip6) {
253                         register struct tcp_seq_hash6 *th;
254                         struct tcp_seq_hash6 *tcp_seq_hash;
255                         const struct in6_addr *src, *dst;
256                         struct tha6 tha;
257 
258                         tcp_seq_hash = tcp_seq_hash6;
259                         src = &ip6->ip6_src;
260                         dst = &ip6->ip6_dst;
261                         if (sport > dport)
262                                 rev = 1;
263                         else if (sport == dport) {
264                                 if (UNALIGNED_MEMCMP(src, dst, sizeof ip6->ip6_dst) > 0)
265                                         rev = 1;
266                         }
267                         if (rev) {
268                                 UNALIGNED_MEMCPY(&tha.src, dst, sizeof ip6->ip6_dst);
269                                 UNALIGNED_MEMCPY(&tha.dst, src, sizeof ip6->ip6_src);
270                                 tha.port = ((u_int)dport) << 16 | sport;
271                         } else {
272                                 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof ip6->ip6_dst);
273                                 UNALIGNED_MEMCPY(&tha.src, src, sizeof ip6->ip6_src);
274                                 tha.port = ((u_int)sport) << 16 | dport;
275                         }
276 
277                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
278                              th->nxt; th = th->nxt)
279                                 if (memcmp((char *)&tha, (char *)&th->addr,
280                                            sizeof(th->addr)) == 0)
281                                         break;
282 
283                         if (!th->nxt || (flags & TH_SYN)) {
284                                 /* didn't find it or new conversation */
285                                 if (th->nxt == NULL) {
286                                         th->nxt = (struct tcp_seq_hash6 *)
287                                                 calloc(1, sizeof(*th));
288                                         if (th->nxt == NULL)
289                                                 (*ndo->ndo_error)(ndo,
290 								  "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                         register struct tcp_seq_hash *th;
308                         struct tcp_seq_hash *tcp_seq_hash;
309                         struct tha tha;
310 
311                         tcp_seq_hash = tcp_seq_hash4;
312                         if (sport > dport)
313                                 rev = 1;
314                         else if (sport == dport) {
315                                 if (UNALIGNED_MEMCMP(&ip->ip_src, &ip->ip_dst, sizeof ip->ip_dst) > 0)
316                                         rev = 1;
317                         }
318                         if (rev) {
319                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_dst, sizeof ip->ip_dst);
320                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_src, sizeof ip->ip_src);
321                                 tha.port = ((u_int)dport) << 16 | sport;
322                         } else {
323                                 UNALIGNED_MEMCPY(&tha.dst, &ip->ip_dst, sizeof ip->ip_dst);
324                                 UNALIGNED_MEMCPY(&tha.src, &ip->ip_src, sizeof ip->ip_src);
325                                 tha.port = ((u_int)sport) << 16 | dport;
326                         }
327 
328                         for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
329                              th->nxt; th = th->nxt)
330                                 if (memcmp((char *)&tha, (char *)&th->addr,
331                                            sizeof(th->addr)) == 0)
332                                         break;
333 
334                         if (!th->nxt || (flags & TH_SYN)) {
335                                 /* didn't find it or new conversation */
336                                 if (th->nxt == NULL) {
337                                         th->nxt = (struct tcp_seq_hash *)
338                                                 calloc(1, sizeof(*th));
339                                         if (th->nxt == NULL)
340                                                 (*ndo->ndo_error)(ndo,
341 								  "tcp_print: calloc");
342                                 }
343                                 th->addr = tha;
344                                 if (rev)
345                                         th->ack = seq, th->seq = ack - 1;
346                                 else
347                                         th->seq = seq, th->ack = ack - 1;
348                         } else {
349                                 if (rev)
350                                         seq -= th->ack, ack -= th->seq;
351                                 else
352                                         seq -= th->seq, ack -= th->ack;
353                         }
354 
355                         thseq = th->seq;
356                         thack = th->ack;
357                 }
358         } else {
359                 /*fool gcc*/
360                 thseq = thack = rev = 0;
361         }
362         if (hlen > length) {
363                 ND_PRINT((ndo, " [bad hdr length %u - too long, > %u]",
364                              hlen, length));
365                 return;
366         }
367 
368         if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
369                 /* Check the checksum, if possible. */
370                 uint16_t sum, tcp_sum;
371 
372                 if (IP_V(ip) == 4) {
373                         if (ND_TTEST2(tp->th_sport, length)) {
374                                 sum = tcp_cksum(ndo, ip, tp, length);
375                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
376 
377                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
378                                 if (sum != 0)
379                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
380                                             in_cksum_shouldbe(tcp_sum, sum)));
381                                 else
382                                         ND_PRINT((ndo, " (correct)"));
383                         }
384                 } else if (IP_V(ip) == 6 && ip6->ip6_plen) {
385                         if (ND_TTEST2(tp->th_sport, length)) {
386                                 sum = tcp6_cksum(ndo, ip6, tp, length);
387                                 tcp_sum = EXTRACT_16BITS(&tp->th_sum);
388 
389                                 ND_PRINT((ndo, ", cksum 0x%04x", tcp_sum));
390                                 if (sum != 0)
391                                         ND_PRINT((ndo, " (incorrect -> 0x%04x)",
392                                             in_cksum_shouldbe(tcp_sum, sum)));
393                                 else
394                                         ND_PRINT((ndo, " (correct)"));
395 
396                         }
397                 }
398         }
399 
400         length -= hlen;
401         if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
402                 ND_PRINT((ndo, ", seq %u", seq));
403 
404                 if (length > 0) {
405                         ND_PRINT((ndo, ":%u", seq + length));
406                 }
407         }
408 
409         if (flags & TH_ACK) {
410                 ND_PRINT((ndo, ", ack %u", ack));
411         }
412 
413         ND_PRINT((ndo, ", win %d", win));
414 
415         if (flags & TH_URG)
416                 ND_PRINT((ndo, ", urg %d", urp));
417         /*
418          * Handle any options.
419          */
420         if (hlen > sizeof(*tp)) {
421                 register const u_char *cp;
422                 register u_int i, opt, datalen;
423                 register u_int len;
424 
425                 hlen -= sizeof(*tp);
426                 cp = (const u_char *)tp + sizeof(*tp);
427                 ND_PRINT((ndo, ", options ["));
428                 while (hlen > 0) {
429                         if (ch != '\0')
430                                 ND_PRINT((ndo, "%c", ch));
431                         ND_TCHECK(*cp);
432                         opt = *cp++;
433                         if (ZEROLENOPT(opt))
434                                 len = 1;
435                         else {
436                                 ND_TCHECK(*cp);
437                                 len = *cp++;	/* total including type, len */
438                                 if (len < 2 || len > hlen)
439                                         goto bad;
440                                 --hlen;		/* account for length byte */
441                         }
442                         --hlen;			/* account for type byte */
443                         datalen = 0;
444 
445 /* Bail if "l" bytes of data are not left or were not captured  */
446 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK2(*cp, l); }
447 
448 
449                         ND_PRINT((ndo, "%s", tok2str(tcp_option_values, "unknown-%u", opt)));
450 
451                         switch (opt) {
452 
453                         case TCPOPT_MAXSEG:
454                                 datalen = 2;
455                                 LENCHECK(datalen);
456                                 ND_PRINT((ndo, " %u", EXTRACT_16BITS(cp)));
457                                 break;
458 
459                         case TCPOPT_WSCALE:
460                                 datalen = 1;
461                                 LENCHECK(datalen);
462                                 ND_PRINT((ndo, " %u", *cp));
463                                 break;
464 
465                         case TCPOPT_SACK:
466                                 datalen = len - 2;
467                                 if (datalen % 8 != 0) {
468                                         ND_PRINT((ndo, " invalid sack"));
469                                 } else {
470                                         uint32_t s, e;
471 
472                                         ND_PRINT((ndo, " %d ", datalen / 8));
473                                         for (i = 0; i < datalen; i += 8) {
474                                                 LENCHECK(i + 4);
475                                                 s = EXTRACT_32BITS(cp + i);
476                                                 LENCHECK(i + 8);
477                                                 e = EXTRACT_32BITS(cp + i + 4);
478                                                 if (rev) {
479                                                         s -= thseq;
480                                                         e -= thseq;
481                                                 } else {
482                                                         s -= thack;
483                                                         e -= thack;
484                                                 }
485                                                 ND_PRINT((ndo, "{%u:%u}", s, e));
486                                         }
487                                 }
488                                 break;
489 
490                         case TCPOPT_CC:
491                         case TCPOPT_CCNEW:
492                         case TCPOPT_CCECHO:
493                         case TCPOPT_ECHO:
494                         case TCPOPT_ECHOREPLY:
495 
496                                 /*
497                                  * those options share their semantics.
498                                  * fall through
499                                  */
500                                 datalen = 4;
501                                 LENCHECK(datalen);
502                                 ND_PRINT((ndo, " %u", EXTRACT_32BITS(cp)));
503                                 break;
504 
505                         case TCPOPT_TIMESTAMP:
506                                 datalen = 8;
507                                 LENCHECK(datalen);
508                                 ND_PRINT((ndo, " val %u ecr %u",
509                                              EXTRACT_32BITS(cp),
510                                              EXTRACT_32BITS(cp + 4)));
511                                 break;
512 
513                         case TCPOPT_SIGNATURE:
514                                 datalen = TCP_SIGLEN;
515                                 LENCHECK(datalen);
516                                 ND_PRINT((ndo, " "));
517 #ifdef HAVE_LIBCRYPTO
518                                 switch (tcp_verify_signature(ndo, ip, tp,
519                                                              bp + TH_OFF(tp) * 4, length, cp)) {
520 
521                                 case SIGNATURE_VALID:
522                                         ND_PRINT((ndo, "valid"));
523                                         break;
524 
525                                 case SIGNATURE_INVALID:
526                                         ND_PRINT((ndo, "invalid"));
527                                         break;
528 
529                                 case CANT_CHECK_SIGNATURE:
530                                         ND_PRINT((ndo, "can't check - "));
531                                         for (i = 0; i < TCP_SIGLEN; ++i)
532                                                 ND_PRINT((ndo, "%02x", cp[i]));
533                                         break;
534                                 }
535 #else
536                                 for (i = 0; i < TCP_SIGLEN; ++i)
537                                         ND_PRINT((ndo, "%02x", cp[i]));
538 #endif
539                                 break;
540 
541                         case TCPOPT_SCPS:
542                                 datalen = 2;
543                                 LENCHECK(datalen);
544                                 ND_PRINT((ndo, " cap %02x id %u", cp[0], cp[1]));
545                                 break;
546 
547                         case TCPOPT_TCPAO:
548                                 datalen = len - 2;
549                                 /* RFC 5925 Section 2.2:
550                                  * "The Length value MUST be greater than or equal to 4."
551                                  * (This includes the Kind and Length fields already processed
552                                  * at this point.)
553                                  */
554                                 if (datalen < 2) {
555                                         ND_PRINT((ndo, " invalid"));
556                                 } else {
557                                         LENCHECK(1);
558                                         ND_PRINT((ndo, " keyid %u", cp[0]));
559                                         LENCHECK(2);
560                                         ND_PRINT((ndo, " rnextkeyid %u", cp[1]));
561                                         if (datalen > 2) {
562                                                 ND_PRINT((ndo, " mac 0x"));
563                                                 for (i = 2; i < datalen; i++) {
564                                                         LENCHECK(i + 1);
565                                                         ND_PRINT((ndo, "%02x", cp[i]));
566                                                 }
567                                         }
568                                 }
569                                 break;
570 
571                         case TCPOPT_EOL:
572                         case TCPOPT_NOP:
573                         case TCPOPT_SACKOK:
574                                 /*
575                                  * Nothing interesting.
576                                  * fall through
577                                  */
578                                 break;
579 
580                         case TCPOPT_UTO:
581                                 datalen = 2;
582                                 LENCHECK(datalen);
583                                 utoval = EXTRACT_16BITS(cp);
584                                 ND_PRINT((ndo, " 0x%x", utoval));
585                                 if (utoval & 0x0001)
586                                         utoval = (utoval >> 1) * 60;
587                                 else
588                                         utoval >>= 1;
589                                 ND_PRINT((ndo, " %u", utoval));
590                                 break;
591 
592                         case TCPOPT_MPTCP:
593                                 datalen = len - 2;
594                                 LENCHECK(datalen);
595                                 if (!mptcp_print(ndo, cp-2, len, flags))
596                                         goto bad;
597                                 break;
598 
599                         case TCPOPT_FASTOPEN:
600                                 datalen = len - 2;
601                                 LENCHECK(datalen);
602                                 ND_PRINT((ndo, " "));
603                                 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
604                                 break;
605 
606                         case TCPOPT_EXPERIMENT2:
607                                 datalen = len - 2;
608                                 LENCHECK(datalen);
609                                 if (datalen < 2)
610                                         goto bad;
611                                 /* RFC6994 */
612                                 magic = EXTRACT_16BITS(cp);
613                                 ND_PRINT((ndo, "-"));
614 
615                                 switch(magic) {
616 
617                                 case 0xf989: /* TCP Fast Open RFC 7413 */
618                                         print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
619                                         break;
620 
621                                 default:
622                                         /* Unknown magic number */
623                                         ND_PRINT((ndo, "%04x", magic));
624                                         break;
625                                 }
626                                 break;
627 
628                         default:
629                                 datalen = len - 2;
630                                 if (datalen)
631                                         ND_PRINT((ndo, " 0x"));
632                                 for (i = 0; i < datalen; ++i) {
633                                         LENCHECK(i + 1);
634                                         ND_PRINT((ndo, "%02x", cp[i]));
635                                 }
636                                 break;
637                         }
638 
639                         /* Account for data printed */
640                         cp += datalen;
641                         hlen -= datalen;
642 
643                         /* Check specification against observed length */
644                         ++datalen;			/* option octet */
645                         if (!ZEROLENOPT(opt))
646                                 ++datalen;		/* size octet */
647                         if (datalen != len)
648                                 ND_PRINT((ndo, "[len %d]", len));
649                         ch = ',';
650                         if (opt == TCPOPT_EOL)
651                                 break;
652                 }
653                 ND_PRINT((ndo, "]"));
654         }
655 
656         /*
657          * Print length field before crawling down the stack.
658          */
659         ND_PRINT((ndo, ", length %u", length));
660 
661         if (length <= 0)
662                 return;
663 
664         /*
665          * Decode payload if necessary.
666          */
667         bp += TH_OFF(tp) * 4;
668         if ((flags & TH_RST) && ndo->ndo_vflag) {
669                 print_tcp_rst_data(ndo, bp, length);
670                 return;
671         }
672 
673         if (ndo->ndo_packettype) {
674                 switch (ndo->ndo_packettype) {
675                 case PT_ZMTP1:
676                         zmtp1_print(ndo, bp, length);
677                         break;
678                 case PT_RESP:
679                         resp_print(ndo, bp, length);
680                         break;
681                 }
682                 return;
683         }
684 
685         if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
686                 telnet_print(ndo, bp, length);
687         } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
688                 ND_PRINT((ndo, ": "));
689                 smtp_print(ndo, bp, length);
690         } else if (IS_SRC_OR_DST_PORT(BGP_PORT))
691                 bgp_print(ndo, bp, length);
692         else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
693                 pptp_print(ndo, bp);
694         else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
695                 resp_print(ndo, bp, length);
696 #ifdef ENABLE_SMB
697         else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT))
698                 nbt_tcp_print(ndo, bp, length);
699 	else if (IS_SRC_OR_DST_PORT(SMB_PORT))
700 		smb_tcp_print(ndo, bp, length);
701 #endif
702         else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
703                 beep_print(ndo, bp, length);
704         else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA))
705                 openflow_print(ndo, bp, length);
706         else if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
707                 ND_PRINT((ndo, ": "));
708                 ftp_print(ndo, bp, length);
709         } else if (IS_SRC_OR_DST_PORT(HTTP_PORT) || IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
710                 ND_PRINT((ndo, ": "));
711                 http_print(ndo, bp, length);
712         } else if (IS_SRC_OR_DST_PORT(RTSP_PORT) || IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
713                 ND_PRINT((ndo, ": "));
714                 rtsp_print(ndo, bp, length);
715         } else if (length > 2 &&
716                  (IS_SRC_OR_DST_PORT(NAMESERVER_PORT))) {
717                 /* domain_print() assumes it does not have to prepend a space before its
718                  * own output to separate it from the output of the calling function. This
719                  * works well with udp_print(), but requires a small prop here.
720                  */
721                 ND_PRINT((ndo, " "));
722 
723                 /*
724                  * TCP DNS query has 2byte length at the head.
725                  * XXX packet could be unaligned, it can go strange
726                  */
727                 ns_print(ndo, bp + 2, length - 2, 0);
728         } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
729                 msdp_print(ndo, bp, length);
730         } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
731                 rpki_rtr_print(ndo, bp, length);
732         }
733         else if (length > 0 && (IS_SRC_OR_DST_PORT(LDP_PORT))) {
734                 ldp_print(ndo, bp, length);
735         }
736         else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
737                  length >= 4 && ND_TTEST2(*bp, 4)) {
738                 /*
739                  * If data present, header length valid, and NFS port used,
740                  * assume NFS.
741                  * Pass offset of data plus 4 bytes for RPC TCP msg length
742                  * to NFS print routines.
743                  */
744                 uint32_t fraglen;
745                 register const struct sunrpc_msg *rp;
746                 enum sunrpc_msg_type direction;
747 
748                 fraglen = EXTRACT_32BITS(bp) & 0x7FFFFFFF;
749                 if (fraglen > (length) - 4)
750                         fraglen = (length) - 4;
751                 rp = (const struct sunrpc_msg *)(bp + 4);
752                 if (ND_TTEST(rp->rm_direction)) {
753                         direction = (enum sunrpc_msg_type)EXTRACT_32BITS(&rp->rm_direction);
754                         if (dport == NFS_PORT && direction == SUNRPC_CALL) {
755                                 ND_PRINT((ndo, ": NFS request xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
756                                 nfsreq_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
757                                 return;
758                         }
759                         if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
760                                 ND_PRINT((ndo, ": NFS reply xid %u ", EXTRACT_32BITS(&rp->rm_xid)));
761                                 nfsreply_print_noaddr(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
762                                 return;
763                         }
764                 }
765         }
766 
767         return;
768  bad:
769         ND_PRINT((ndo, "[bad opt]"));
770         if (ch != '\0')
771                 ND_PRINT((ndo, ">"));
772         return;
773  trunc:
774         ND_PRINT((ndo, "[|tcp]"));
775         if (ch != '\0')
776                 ND_PRINT((ndo, ">"));
777 }
778 
779 /*
780  * RFC1122 says the following on data in RST segments:
781  *
782  *         4.2.2.12  RST Segment: RFC-793 Section 3.4
783  *
784  *            A TCP SHOULD allow a received RST segment to include data.
785  *
786  *            DISCUSSION
787  *                 It has been suggested that a RST segment could contain
788  *                 ASCII text that encoded and explained the cause of the
789  *                 RST.  No standard has yet been established for such
790  *                 data.
791  *
792  */
793 
794 static void
795 print_tcp_rst_data(netdissect_options *ndo,
796                    register const u_char *sp, u_int length)
797 {
798         int c;
799 
800         ND_PRINT((ndo, ND_TTEST2(*sp, length) ? " [RST" : " [!RST"));
801         if (length > MAX_RST_DATA_LEN) {
802                 length = MAX_RST_DATA_LEN;	/* can use -X for longer */
803                 ND_PRINT((ndo, "+"));			/* indicate we truncate */
804         }
805         ND_PRINT((ndo, " "));
806         while (length-- && sp < ndo->ndo_snapend) {
807                 c = *sp++;
808                 safeputchar(ndo, c);
809         }
810         ND_PRINT((ndo, "]"));
811 }
812 
813 static void
814 print_tcp_fastopen_option(netdissect_options *ndo, register const u_char *cp,
815                           u_int datalen, int exp)
816 {
817         u_int i;
818 
819         if (exp)
820                 ND_PRINT((ndo, "tfo"));
821 
822         if (datalen == 0) {
823                 /* Fast Open Cookie Request */
824                 ND_PRINT((ndo, " cookiereq"));
825         } else {
826                 /* Fast Open Cookie */
827                 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
828                         ND_PRINT((ndo, " invalid"));
829                 } else {
830                         ND_PRINT((ndo, " cookie "));
831                         for (i = 0; i < datalen; ++i)
832                                 ND_PRINT((ndo, "%02x", cp[i]));
833                 }
834         }
835 }
836 
837 #ifdef HAVE_LIBCRYPTO
838 USES_APPLE_DEPRECATED_API
839 static int
840 tcp_verify_signature(netdissect_options *ndo,
841                      const struct ip *ip, const struct tcphdr *tp,
842                      const u_char *data, int length, const u_char *rcvsig)
843 {
844         struct tcphdr tp1;
845         u_char sig[TCP_SIGLEN];
846         char zero_proto = 0;
847         MD5_CTX ctx;
848         uint16_t savecsum, tlen;
849         const struct ip6_hdr *ip6;
850         uint32_t len32;
851         uint8_t nxt;
852 
853 	if (data + length > ndo->ndo_snapend) {
854 		ND_PRINT((ndo, "snaplen too short, "));
855 		return (CANT_CHECK_SIGNATURE);
856 	}
857 
858         tp1 = *tp;
859 
860         if (ndo->ndo_sigsecret == NULL) {
861 		ND_PRINT((ndo, "shared secret not supplied with -M, "));
862                 return (CANT_CHECK_SIGNATURE);
863         }
864 
865         MD5_Init(&ctx);
866         /*
867          * Step 1: Update MD5 hash with IP pseudo-header.
868          */
869         if (IP_V(ip) == 4) {
870                 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
871                 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
872                 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
873                 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
874                 tlen = EXTRACT_16BITS(&ip->ip_len) - IP_HL(ip) * 4;
875                 tlen = htons(tlen);
876                 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
877         } else if (IP_V(ip) == 6) {
878                 ip6 = (const struct ip6_hdr *)ip;
879                 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
880                 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
881                 len32 = htonl(EXTRACT_16BITS(&ip6->ip6_plen));
882                 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
883                 nxt = 0;
884                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
885                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
886                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
887                 nxt = IPPROTO_TCP;
888                 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
889         } else {
890 		ND_PRINT((ndo, "IP version not 4 or 6, "));
891                 return (CANT_CHECK_SIGNATURE);
892         }
893 
894         /*
895          * Step 2: Update MD5 hash with TCP header, excluding options.
896          * The TCP checksum must be set to zero.
897          */
898         savecsum = tp1.th_sum;
899         tp1.th_sum = 0;
900         MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
901         tp1.th_sum = savecsum;
902         /*
903          * Step 3: Update MD5 hash with TCP segment data, if present.
904          */
905         if (length > 0)
906                 MD5_Update(&ctx, data, length);
907         /*
908          * Step 4: Update MD5 hash with shared secret.
909          */
910         MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
911         MD5_Final(sig, &ctx);
912 
913         if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
914                 return (SIGNATURE_VALID);
915         else
916                 return (SIGNATURE_INVALID);
917 }
918 USES_APPLE_RST
919 #endif /* HAVE_LIBCRYPTO */
920 
921 /*
922  * Local Variables:
923  * c-style: whitesmith
924  * c-basic-offset: 8
925  * End:
926  */
927