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 #include <config.h>
34
35 #include "netdissect-stdinc.h"
36
37 #include <stdlib.h>
38 #include <string.h>
39
40 #include "netdissect.h"
41 #include "addrtoname.h"
42 #include "extract.h"
43
44 #include "diag-control.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, u_int length, const u_char *rcvsig);
61 #endif
62
63 static void print_tcp_rst_data(netdissect_options *, const u_char *sp, u_int length);
64 static void print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
65 u_int datalen, int exp);
66
67 #define MAX_RST_DATA_LEN 30
68
69
70 struct tha {
71 nd_ipv4 src;
72 nd_ipv4 dst;
73 u_int port;
74 };
75
76 struct tcp_seq_hash {
77 struct tcp_seq_hash *nxt;
78 struct tha addr;
79 uint32_t seq;
80 uint32_t ack;
81 };
82
83 struct tha6 {
84 nd_ipv6 src;
85 nd_ipv6 dst;
86 u_int port;
87 };
88
89 struct tcp_seq_hash6 {
90 struct tcp_seq_hash6 *nxt;
91 struct tha6 addr;
92 uint32_t seq;
93 uint32_t ack;
94 };
95
96 #define TSEQ_HASHSIZE 919
97
98 /* These tcp options 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, "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 uint16_t
tcp_cksum(netdissect_options * ndo,const struct ip * ip,const struct tcphdr * tp,u_int len)140 tcp_cksum(netdissect_options *ndo,
141 const struct ip *ip,
142 const struct tcphdr *tp,
143 u_int len)
144 {
145 return nextproto4_cksum(ndo, ip, (const uint8_t *)tp, len, len,
146 IPPROTO_TCP);
147 }
148
149 static uint16_t
tcp6_cksum(netdissect_options * ndo,const struct ip6_hdr * ip6,const struct tcphdr * tp,u_int len)150 tcp6_cksum(netdissect_options *ndo,
151 const struct ip6_hdr *ip6,
152 const struct tcphdr *tp,
153 u_int len)
154 {
155 return nextproto6_cksum(ndo, ip6, (const uint8_t *)tp, len, len,
156 IPPROTO_TCP);
157 }
158
159 void
tcp_print(netdissect_options * ndo,const u_char * bp,u_int length,const u_char * bp2,int fragmented)160 tcp_print(netdissect_options *ndo,
161 const u_char *bp, u_int length,
162 const u_char *bp2, int fragmented)
163 {
164 const struct tcphdr *tp;
165 const struct ip *ip;
166 u_char flags;
167 u_int hlen;
168 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 int rev;
174 const struct ip6_hdr *ip6;
175 u_int header_len; /* Header length in bytes */
176
177 ndo->ndo_protocol = "tcp";
178 tp = (const struct tcphdr *)bp;
179 ip = (const struct ip *)bp2;
180 if (IP_V(ip) == 6)
181 ip6 = (const struct ip6_hdr *)bp2;
182 else
183 ip6 = NULL;
184 ch = '\0';
185 if (!ND_TTEST_2(tp->th_dport)) {
186 if (ip6) {
187 ND_PRINT("%s > %s:",
188 GET_IP6ADDR_STRING(ip6->ip6_src),
189 GET_IP6ADDR_STRING(ip6->ip6_dst));
190 } else {
191 ND_PRINT("%s > %s:",
192 GET_IPADDR_STRING(ip->ip_src),
193 GET_IPADDR_STRING(ip->ip_dst));
194 }
195 nd_print_trunc(ndo);
196 return;
197 }
198
199 sport = GET_BE_U_2(tp->th_sport);
200 dport = GET_BE_U_2(tp->th_dport);
201
202 if (ip6) {
203 if (GET_U_1(ip6->ip6_nxt) == IPPROTO_TCP) {
204 ND_PRINT("%s.%s > %s.%s: ",
205 GET_IP6ADDR_STRING(ip6->ip6_src),
206 tcpport_string(ndo, sport),
207 GET_IP6ADDR_STRING(ip6->ip6_dst),
208 tcpport_string(ndo, dport));
209 } else {
210 ND_PRINT("%s > %s: ",
211 tcpport_string(ndo, sport), tcpport_string(ndo, dport));
212 }
213 } else {
214 if (GET_U_1(ip->ip_p) == IPPROTO_TCP) {
215 ND_PRINT("%s.%s > %s.%s: ",
216 GET_IPADDR_STRING(ip->ip_src),
217 tcpport_string(ndo, sport),
218 GET_IPADDR_STRING(ip->ip_dst),
219 tcpport_string(ndo, dport));
220 } else {
221 ND_PRINT("%s > %s: ",
222 tcpport_string(ndo, sport), tcpport_string(ndo, dport));
223 }
224 }
225
226 ND_TCHECK_SIZE(tp);
227
228 hlen = TH_OFF(tp) * 4;
229
230 if (hlen < sizeof(*tp)) {
231 ND_PRINT(" tcp %u [bad hdr length %u - too short, < %zu]",
232 length - hlen, hlen, sizeof(*tp));
233 return;
234 }
235
236 seq = GET_BE_U_4(tp->th_seq);
237 ack = GET_BE_U_4(tp->th_ack);
238 win = GET_BE_U_2(tp->th_win);
239 urp = GET_BE_U_2(tp->th_urp);
240
241 if (ndo->ndo_qflag) {
242 ND_PRINT("tcp %u", length - hlen);
243 if (hlen > length) {
244 ND_PRINT(" [bad hdr length %u - too long, > %u]",
245 hlen, length);
246 }
247 return;
248 }
249
250 flags = GET_U_1(tp->th_flags);
251 ND_PRINT("Flags [%s]", bittok2str_nosep(tcp_flag_values, "none", flags));
252
253 if (!ndo->ndo_Sflag && (flags & TH_ACK)) {
254 /*
255 * Find (or record) the initial sequence numbers for
256 * this conversation. (we pick an arbitrary
257 * collating order so there's only one entry for
258 * both directions).
259 */
260 rev = 0;
261 if (ip6) {
262 struct tcp_seq_hash6 *th;
263 struct tcp_seq_hash6 *tcp_seq_hash;
264 const void *src, *dst;
265 struct tha6 tha;
266
267 tcp_seq_hash = tcp_seq_hash6;
268 src = (const void *)ip6->ip6_src;
269 dst = (const void *)ip6->ip6_dst;
270 if (sport > dport)
271 rev = 1;
272 else if (sport == dport) {
273 if (UNALIGNED_MEMCMP(src, dst, sizeof(ip6->ip6_dst)) > 0)
274 rev = 1;
275 }
276 if (rev) {
277 UNALIGNED_MEMCPY(&tha.src, dst, sizeof(ip6->ip6_dst));
278 UNALIGNED_MEMCPY(&tha.dst, src, sizeof(ip6->ip6_src));
279 tha.port = ((u_int)dport) << 16 | sport;
280 } else {
281 UNALIGNED_MEMCPY(&tha.dst, dst, sizeof(ip6->ip6_dst));
282 UNALIGNED_MEMCPY(&tha.src, src, sizeof(ip6->ip6_src));
283 tha.port = ((u_int)sport) << 16 | dport;
284 }
285
286 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
287 th->nxt; th = th->nxt)
288 if (memcmp((char *)&tha, (char *)&th->addr,
289 sizeof(th->addr)) == 0)
290 break;
291
292 if (!th->nxt || (flags & TH_SYN)) {
293 /* didn't find it or new conversation */
294 /* calloc() return used by the 'tcp_seq_hash6'
295 hash table: do not free() */
296 if (th->nxt == NULL) {
297 th->nxt = (struct tcp_seq_hash6 *)
298 calloc(1, sizeof(*th));
299 if (th->nxt == NULL)
300 (*ndo->ndo_error)(ndo,
301 S_ERR_ND_MEM_ALLOC,
302 "%s: calloc", __func__);
303 }
304 th->addr = tha;
305 if (rev)
306 th->ack = seq, th->seq = ack - 1;
307 else
308 th->seq = seq, th->ack = ack - 1;
309 } else {
310 if (rev)
311 seq -= th->ack, ack -= th->seq;
312 else
313 seq -= th->seq, ack -= th->ack;
314 }
315
316 thseq = th->seq;
317 thack = th->ack;
318 } else {
319 struct tcp_seq_hash *th;
320 struct tcp_seq_hash *tcp_seq_hash;
321 struct tha tha;
322
323 tcp_seq_hash = tcp_seq_hash4;
324 if (sport > dport)
325 rev = 1;
326 else if (sport == dport) {
327 if (UNALIGNED_MEMCMP(ip->ip_src, ip->ip_dst, sizeof(ip->ip_dst)) > 0)
328 rev = 1;
329 }
330 if (rev) {
331 UNALIGNED_MEMCPY(&tha.src, ip->ip_dst,
332 sizeof(ip->ip_dst));
333 UNALIGNED_MEMCPY(&tha.dst, ip->ip_src,
334 sizeof(ip->ip_src));
335 tha.port = ((u_int)dport) << 16 | sport;
336 } else {
337 UNALIGNED_MEMCPY(&tha.dst, ip->ip_dst,
338 sizeof(ip->ip_dst));
339 UNALIGNED_MEMCPY(&tha.src, ip->ip_src,
340 sizeof(ip->ip_src));
341 tha.port = ((u_int)sport) << 16 | dport;
342 }
343
344 for (th = &tcp_seq_hash[tha.port % TSEQ_HASHSIZE];
345 th->nxt; th = th->nxt)
346 if (memcmp((char *)&tha, (char *)&th->addr,
347 sizeof(th->addr)) == 0)
348 break;
349
350 if (!th->nxt || (flags & TH_SYN)) {
351 /* didn't find it or new conversation */
352 /* calloc() return used by the 'tcp_seq_hash4'
353 hash table: do not free() */
354 if (th->nxt == NULL) {
355 th->nxt = (struct tcp_seq_hash *)
356 calloc(1, sizeof(*th));
357 if (th->nxt == NULL)
358 (*ndo->ndo_error)(ndo,
359 S_ERR_ND_MEM_ALLOC,
360 "%s: calloc", __func__);
361 }
362 th->addr = tha;
363 if (rev)
364 th->ack = seq, th->seq = ack - 1;
365 else
366 th->seq = seq, th->ack = ack - 1;
367 } else {
368 if (rev)
369 seq -= th->ack, ack -= th->seq;
370 else
371 seq -= th->seq, ack -= th->ack;
372 }
373
374 thseq = th->seq;
375 thack = th->ack;
376 }
377 } else {
378 /*fool gcc*/
379 thseq = thack = rev = 0;
380 }
381 if (hlen > length) {
382 ND_PRINT(" [bad hdr length %u - too long, > %u]",
383 hlen, length);
384 return;
385 }
386
387 if (ndo->ndo_vflag && !ndo->ndo_Kflag && !fragmented) {
388 /* Check the checksum, if possible. */
389 uint16_t sum, tcp_sum;
390
391 if (IP_V(ip) == 4) {
392 if (ND_TTEST_LEN(tp->th_sport, length)) {
393 sum = tcp_cksum(ndo, ip, tp, length);
394 tcp_sum = GET_BE_U_2(tp->th_sum);
395
396 ND_PRINT(", cksum 0x%04x", tcp_sum);
397 if (sum != 0)
398 ND_PRINT(" (incorrect -> 0x%04x)",
399 in_cksum_shouldbe(tcp_sum, sum));
400 else
401 ND_PRINT(" (correct)");
402 }
403 } else if (IP_V(ip) == 6) {
404 if (ND_TTEST_LEN(tp->th_sport, length)) {
405 sum = tcp6_cksum(ndo, ip6, tp, length);
406 tcp_sum = GET_BE_U_2(tp->th_sum);
407
408 ND_PRINT(", cksum 0x%04x", tcp_sum);
409 if (sum != 0)
410 ND_PRINT(" (incorrect -> 0x%04x)",
411 in_cksum_shouldbe(tcp_sum, sum));
412 else
413 ND_PRINT(" (correct)");
414
415 }
416 }
417 }
418
419 length -= hlen;
420 if (ndo->ndo_vflag > 1 || length > 0 || flags & (TH_SYN | TH_FIN | TH_RST)) {
421 ND_PRINT(", seq %u", seq);
422
423 if (length > 0) {
424 ND_PRINT(":%u", seq + length);
425 }
426 }
427
428 if (flags & TH_ACK) {
429 ND_PRINT(", ack %u", ack);
430 }
431
432 ND_PRINT(", win %u", win);
433
434 if (flags & TH_URG)
435 ND_PRINT(", urg %u", urp);
436 /*
437 * Handle any options.
438 */
439 if (hlen > sizeof(*tp)) {
440 const u_char *cp;
441 u_int i, opt, datalen;
442 u_int len;
443
444 hlen -= sizeof(*tp);
445 cp = (const u_char *)tp + sizeof(*tp);
446 ND_PRINT(", options [");
447 while (hlen > 0) {
448 if (ch != '\0')
449 ND_PRINT("%c", ch);
450 opt = GET_U_1(cp);
451 cp++;
452 if (ZEROLENOPT(opt))
453 len = 1;
454 else {
455 len = GET_U_1(cp);
456 cp++; /* total including type, len */
457 if (len < 2 || len > hlen)
458 goto bad;
459 --hlen; /* account for length byte */
460 }
461 --hlen; /* account for type byte */
462 datalen = 0;
463
464 /* Bail if "l" bytes of data are not left or were not captured */
465 #define LENCHECK(l) { if ((l) > hlen) goto bad; ND_TCHECK_LEN(cp, l); }
466
467
468 ND_PRINT("%s", tok2str(tcp_option_values, "unknown-%u", opt));
469
470 switch (opt) {
471
472 case TCPOPT_MAXSEG:
473 datalen = 2;
474 LENCHECK(datalen);
475 ND_PRINT(" %u", GET_BE_U_2(cp));
476 break;
477
478 case TCPOPT_WSCALE:
479 datalen = 1;
480 LENCHECK(datalen);
481 ND_PRINT(" %u", GET_U_1(cp));
482 break;
483
484 case TCPOPT_SACK:
485 datalen = len - 2;
486 if (datalen % 8 != 0) {
487 ND_PRINT(" invalid sack");
488 } else {
489 uint32_t s, e;
490
491 ND_PRINT(" %u ", datalen / 8);
492 for (i = 0; i < datalen; i += 8) {
493 LENCHECK(i + 4);
494 s = GET_BE_U_4(cp + i);
495 LENCHECK(i + 8);
496 e = GET_BE_U_4(cp + i + 4);
497 if (rev) {
498 s -= thseq;
499 e -= thseq;
500 } else {
501 s -= thack;
502 e -= thack;
503 }
504 ND_PRINT("{%u:%u}", s, e);
505 }
506 }
507 break;
508
509 case TCPOPT_CC:
510 case TCPOPT_CCNEW:
511 case TCPOPT_CCECHO:
512 case TCPOPT_ECHO:
513 case TCPOPT_ECHOREPLY:
514
515 /*
516 * those options share their semantics.
517 * fall through
518 */
519 datalen = 4;
520 LENCHECK(datalen);
521 ND_PRINT(" %u", GET_BE_U_4(cp));
522 break;
523
524 case TCPOPT_TIMESTAMP:
525 datalen = 8;
526 LENCHECK(datalen);
527 ND_PRINT(" val %u ecr %u",
528 GET_BE_U_4(cp),
529 GET_BE_U_4(cp + 4));
530 break;
531
532 case TCPOPT_SIGNATURE:
533 datalen = TCP_SIGLEN;
534 LENCHECK(datalen);
535 ND_PRINT(" ");
536 #ifdef HAVE_LIBCRYPTO
537 switch (tcp_verify_signature(ndo, ip, tp,
538 bp + TH_OFF(tp) * 4, length, cp)) {
539
540 case SIGNATURE_VALID:
541 ND_PRINT("valid");
542 break;
543
544 case SIGNATURE_INVALID:
545 nd_print_invalid(ndo);
546 break;
547
548 case CANT_CHECK_SIGNATURE:
549 ND_PRINT("can't check - ");
550 for (i = 0; i < TCP_SIGLEN; ++i)
551 ND_PRINT("%02x",
552 GET_U_1(cp + i));
553 break;
554 }
555 #else
556 for (i = 0; i < TCP_SIGLEN; ++i)
557 ND_PRINT("%02x", GET_U_1(cp + i));
558 #endif
559 break;
560
561 case TCPOPT_SCPS:
562 datalen = 2;
563 LENCHECK(datalen);
564 ND_PRINT(" cap %02x id %u", GET_U_1(cp),
565 GET_U_1(cp + 1));
566 break;
567
568 case TCPOPT_TCPAO:
569 datalen = len - 2;
570 /* RFC 5925 Section 2.2:
571 * "The Length value MUST be greater than or equal to 4."
572 * (This includes the Kind and Length fields already processed
573 * at this point.)
574 */
575 if (datalen < 2) {
576 nd_print_invalid(ndo);
577 } else {
578 LENCHECK(1);
579 ND_PRINT(" keyid %u", GET_U_1(cp));
580 LENCHECK(2);
581 ND_PRINT(" rnextkeyid %u",
582 GET_U_1(cp + 1));
583 if (datalen > 2) {
584 ND_PRINT(" mac 0x");
585 for (i = 2; i < datalen; i++) {
586 LENCHECK(i + 1);
587 ND_PRINT("%02x",
588 GET_U_1(cp + i));
589 }
590 }
591 }
592 break;
593
594 case TCPOPT_EOL:
595 case TCPOPT_NOP:
596 case TCPOPT_SACKOK:
597 /*
598 * Nothing interesting.
599 * fall through
600 */
601 break;
602
603 case TCPOPT_UTO:
604 datalen = 2;
605 LENCHECK(datalen);
606 utoval = GET_BE_U_2(cp);
607 ND_PRINT(" 0x%x", utoval);
608 if (utoval & 0x0001)
609 utoval = (utoval >> 1) * 60;
610 else
611 utoval >>= 1;
612 ND_PRINT(" %u", utoval);
613 break;
614
615 case TCPOPT_MPTCP:
616 {
617 const u_char *snapend_save;
618 int ret;
619
620 datalen = len - 2;
621 LENCHECK(datalen);
622 /* Update the snapend to the end of the option
623 * before calling mptcp_print(). Some options
624 * (MPTCP or others) may be present after a
625 * MPTCP option. This prevents that, in
626 * mptcp_print(), the remaining length < the
627 * remaining caplen.
628 */
629 snapend_save = ndo->ndo_snapend;
630 ndo->ndo_snapend = ND_MIN(cp - 2 + len,
631 ndo->ndo_snapend);
632 ret = mptcp_print(ndo, cp - 2, len, flags);
633 ndo->ndo_snapend = snapend_save;
634 if (!ret)
635 goto bad;
636 break;
637 }
638
639 case TCPOPT_FASTOPEN:
640 datalen = len - 2;
641 LENCHECK(datalen);
642 ND_PRINT(" ");
643 print_tcp_fastopen_option(ndo, cp, datalen, FALSE);
644 break;
645
646 case TCPOPT_EXPERIMENT2:
647 datalen = len - 2;
648 LENCHECK(datalen);
649 if (datalen < 2)
650 goto bad;
651 /* RFC6994 */
652 magic = GET_BE_U_2(cp);
653 ND_PRINT("-");
654
655 switch(magic) {
656
657 case 0xf989: /* TCP Fast Open RFC 7413 */
658 print_tcp_fastopen_option(ndo, cp + 2, datalen - 2, TRUE);
659 break;
660
661 default:
662 /* Unknown magic number */
663 ND_PRINT("%04x", magic);
664 break;
665 }
666 break;
667
668 default:
669 datalen = len - 2;
670 if (datalen)
671 ND_PRINT(" 0x");
672 for (i = 0; i < datalen; ++i) {
673 LENCHECK(i + 1);
674 ND_PRINT("%02x", GET_U_1(cp + i));
675 }
676 break;
677 }
678
679 /* Account for data printed */
680 cp += datalen;
681 hlen -= datalen;
682
683 /* Check specification against observed length */
684 ++datalen; /* option octet */
685 if (!ZEROLENOPT(opt))
686 ++datalen; /* size octet */
687 if (datalen != len)
688 ND_PRINT("[len %u]", len);
689 ch = ',';
690 if (opt == TCPOPT_EOL)
691 break;
692 }
693 ND_PRINT("]");
694 }
695
696 /*
697 * Print length field before crawling down the stack.
698 */
699 ND_PRINT(", length %u", length);
700
701 if (length == 0)
702 return;
703
704 /*
705 * Decode payload if necessary.
706 */
707 header_len = TH_OFF(tp) * 4;
708 /*
709 * Do a bounds check before decoding the payload.
710 * At least the header data is required.
711 */
712 if (!ND_TTEST_LEN(bp, header_len)) {
713 ND_PRINT(" [remaining caplen(%u) < header length(%u)]",
714 ND_BYTES_AVAILABLE_AFTER(bp), header_len);
715 nd_trunc_longjmp(ndo);
716 }
717 bp += header_len;
718 if ((flags & TH_RST) && ndo->ndo_vflag) {
719 print_tcp_rst_data(ndo, bp, length);
720 return;
721 }
722
723 if (ndo->ndo_packettype) {
724 switch (ndo->ndo_packettype) {
725 case PT_ZMTP1:
726 zmtp1_print(ndo, bp, length);
727 break;
728 case PT_RESP:
729 resp_print(ndo, bp, length);
730 break;
731 case PT_DOMAIN:
732 /* over_tcp: TRUE, is_mdns: FALSE */
733 domain_print(ndo, bp, length, TRUE, FALSE);
734 break;
735 }
736 return;
737 }
738
739 if (IS_SRC_OR_DST_PORT(FTP_PORT)) {
740 ND_PRINT(": ");
741 ftp_print(ndo, bp, length);
742 } else if (IS_SRC_OR_DST_PORT(SSH_PORT)) {
743 ssh_print(ndo, bp, length);
744 } else if (IS_SRC_OR_DST_PORT(TELNET_PORT)) {
745 telnet_print(ndo, bp, length);
746 } else if (IS_SRC_OR_DST_PORT(SMTP_PORT)) {
747 ND_PRINT(": ");
748 smtp_print(ndo, bp, length);
749 } else if (IS_SRC_OR_DST_PORT(WHOIS_PORT)) {
750 ND_PRINT(": ");
751 whois_print(ndo, bp, length);
752 } else if (IS_SRC_OR_DST_PORT(NAMESERVER_PORT)) {
753 /* over_tcp: TRUE, is_mdns: FALSE */
754 domain_print(ndo, bp, length, TRUE, FALSE);
755 } else if (IS_SRC_OR_DST_PORT(HTTP_PORT)) {
756 ND_PRINT(": ");
757 http_print(ndo, bp, length);
758 #ifdef ENABLE_SMB
759 } else if (IS_SRC_OR_DST_PORT(NETBIOS_SSN_PORT)) {
760 nbt_tcp_print(ndo, bp, length);
761 #endif
762 } else if (IS_SRC_OR_DST_PORT(BGP_PORT)) {
763 bgp_print(ndo, bp, length);
764 } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT)) {
765 rpki_rtr_print(ndo, bp, length);
766 #ifdef ENABLE_SMB
767 } else if (IS_SRC_OR_DST_PORT(SMB_PORT)) {
768 smb_tcp_print(ndo, bp, length);
769 #endif
770 } else if (IS_SRC_OR_DST_PORT(RTSP_PORT)) {
771 ND_PRINT(": ");
772 rtsp_print(ndo, bp, length);
773 } else if (IS_SRC_OR_DST_PORT(MSDP_PORT)) {
774 msdp_print(ndo, bp, length);
775 } else if (IS_SRC_OR_DST_PORT(LDP_PORT)) {
776 ldp_print(ndo, bp, length);
777 } else if (IS_SRC_OR_DST_PORT(PPTP_PORT))
778 pptp_print(ndo, bp);
779 else if (IS_SRC_OR_DST_PORT(REDIS_PORT))
780 resp_print(ndo, bp, length);
781 else if (IS_SRC_OR_DST_PORT(BEEP_PORT))
782 beep_print(ndo, bp, length);
783 else if (IS_SRC_OR_DST_PORT(OPENFLOW_PORT_OLD) || IS_SRC_OR_DST_PORT(OPENFLOW_PORT_IANA)) {
784 openflow_print(ndo, bp, length);
785 } else if (IS_SRC_OR_DST_PORT(HTTP_PORT_ALT)) {
786 ND_PRINT(": ");
787 http_print(ndo, bp, length);
788 } else if (IS_SRC_OR_DST_PORT(RTSP_PORT_ALT)) {
789 ND_PRINT(": ");
790 rtsp_print(ndo, bp, length);
791 } else if ((IS_SRC_OR_DST_PORT(NFS_PORT)) &&
792 length >= 4 && ND_TTEST_4(bp)) {
793 /*
794 * If data present, header length valid, and NFS port used,
795 * assume NFS.
796 * Pass offset of data plus 4 bytes for RPC TCP msg length
797 * to NFS print routines.
798 */
799 uint32_t fraglen;
800 const struct sunrpc_msg *rp;
801 enum sunrpc_msg_type direction;
802
803 fraglen = GET_BE_U_4(bp) & 0x7FFFFFFF;
804 if (fraglen > (length) - 4)
805 fraglen = (length) - 4;
806 rp = (const struct sunrpc_msg *)(bp + 4);
807 if (ND_TTEST_4(rp->rm_direction)) {
808 direction = (enum sunrpc_msg_type) GET_BE_U_4(rp->rm_direction);
809 if (dport == NFS_PORT && direction == SUNRPC_CALL) {
810 ND_PRINT(": NFS request xid %u ",
811 GET_BE_U_4(rp->rm_xid));
812 nfsreq_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
813 return;
814 }
815 if (sport == NFS_PORT && direction == SUNRPC_REPLY) {
816 ND_PRINT(": NFS reply xid %u ",
817 GET_BE_U_4(rp->rm_xid));
818 nfsreply_noaddr_print(ndo, (const u_char *)rp, fraglen, (const u_char *)ip);
819 return;
820 }
821 }
822 }
823
824 return;
825 bad:
826 ND_PRINT("[bad opt]");
827 if (ch != '\0')
828 ND_PRINT("]");
829 return;
830 trunc:
831 nd_print_trunc(ndo);
832 if (ch != '\0')
833 ND_PRINT(">");
834 }
835
836 /*
837 * RFC1122 says the following on data in RST segments:
838 *
839 * 4.2.2.12 RST Segment: RFC-793 Section 3.4
840 *
841 * A TCP SHOULD allow a received RST segment to include data.
842 *
843 * DISCUSSION
844 * It has been suggested that a RST segment could contain
845 * ASCII text that encoded and explained the cause of the
846 * RST. No standard has yet been established for such
847 * data.
848 *
849 */
850
851 static void
print_tcp_rst_data(netdissect_options * ndo,const u_char * sp,u_int length)852 print_tcp_rst_data(netdissect_options *ndo,
853 const u_char *sp, u_int length)
854 {
855 u_char c;
856
857 ND_PRINT(ND_TTEST_LEN(sp, length) ? " [RST" : " [!RST");
858 if (length > MAX_RST_DATA_LEN) {
859 length = MAX_RST_DATA_LEN; /* can use -X for longer */
860 ND_PRINT("+"); /* indicate we truncate */
861 }
862 ND_PRINT(" ");
863 while (length && sp < ndo->ndo_snapend) {
864 c = GET_U_1(sp);
865 sp++;
866 fn_print_char(ndo, c);
867 length--;
868 }
869 ND_PRINT("]");
870 }
871
872 static void
print_tcp_fastopen_option(netdissect_options * ndo,const u_char * cp,u_int datalen,int exp)873 print_tcp_fastopen_option(netdissect_options *ndo, const u_char *cp,
874 u_int datalen, int exp)
875 {
876 u_int i;
877
878 if (exp)
879 ND_PRINT("tfo");
880
881 if (datalen == 0) {
882 /* Fast Open Cookie Request */
883 ND_PRINT(" cookiereq");
884 } else {
885 /* Fast Open Cookie */
886 if (datalen % 2 != 0 || datalen < 4 || datalen > 16) {
887 nd_print_invalid(ndo);
888 } else {
889 ND_PRINT(" cookie ");
890 for (i = 0; i < datalen; ++i)
891 ND_PRINT("%02x", GET_U_1(cp + i));
892 }
893 }
894 }
895
896 #ifdef HAVE_LIBCRYPTO
897 DIAG_OFF_DEPRECATION
898 static int
tcp_verify_signature(netdissect_options * ndo,const struct ip * ip,const struct tcphdr * tp,const u_char * data,u_int length,const u_char * rcvsig)899 tcp_verify_signature(netdissect_options *ndo,
900 const struct ip *ip, const struct tcphdr *tp,
901 const u_char *data, u_int length, const u_char *rcvsig)
902 {
903 struct tcphdr tp1;
904 u_char sig[TCP_SIGLEN];
905 char zero_proto = 0;
906 MD5_CTX ctx;
907 uint16_t savecsum, tlen;
908 const struct ip6_hdr *ip6;
909 uint32_t len32;
910 uint8_t nxt;
911
912 if (data + length > ndo->ndo_snapend) {
913 ND_PRINT("snaplen too short, ");
914 return (CANT_CHECK_SIGNATURE);
915 }
916
917 tp1 = *tp;
918
919 if (ndo->ndo_sigsecret == NULL) {
920 ND_PRINT("shared secret not supplied with -M, ");
921 return (CANT_CHECK_SIGNATURE);
922 }
923
924 MD5_Init(&ctx);
925 /*
926 * Step 1: Update MD5 hash with IP pseudo-header.
927 */
928 if (IP_V(ip) == 4) {
929 MD5_Update(&ctx, (const char *)&ip->ip_src, sizeof(ip->ip_src));
930 MD5_Update(&ctx, (const char *)&ip->ip_dst, sizeof(ip->ip_dst));
931 MD5_Update(&ctx, (const char *)&zero_proto, sizeof(zero_proto));
932 MD5_Update(&ctx, (const char *)&ip->ip_p, sizeof(ip->ip_p));
933 tlen = GET_BE_U_2(ip->ip_len) - IP_HL(ip) * 4;
934 tlen = htons(tlen);
935 MD5_Update(&ctx, (const char *)&tlen, sizeof(tlen));
936 } else if (IP_V(ip) == 6) {
937 ip6 = (const struct ip6_hdr *)ip;
938 MD5_Update(&ctx, (const char *)&ip6->ip6_src, sizeof(ip6->ip6_src));
939 MD5_Update(&ctx, (const char *)&ip6->ip6_dst, sizeof(ip6->ip6_dst));
940 len32 = htonl(GET_BE_U_2(ip6->ip6_plen));
941 MD5_Update(&ctx, (const char *)&len32, sizeof(len32));
942 nxt = 0;
943 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
944 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
945 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
946 nxt = IPPROTO_TCP;
947 MD5_Update(&ctx, (const char *)&nxt, sizeof(nxt));
948 } else {
949 ND_PRINT("IP version not 4 or 6, ");
950 return (CANT_CHECK_SIGNATURE);
951 }
952
953 /*
954 * Step 2: Update MD5 hash with TCP header, excluding options.
955 * The TCP checksum must be set to zero.
956 */
957 memcpy(&savecsum, tp1.th_sum, sizeof(savecsum));
958 memset(tp1.th_sum, 0, sizeof(tp1.th_sum));
959 MD5_Update(&ctx, (const char *)&tp1, sizeof(struct tcphdr));
960 memcpy(tp1.th_sum, &savecsum, sizeof(tp1.th_sum));
961 /*
962 * Step 3: Update MD5 hash with TCP segment data, if present.
963 */
964 if (length > 0)
965 MD5_Update(&ctx, data, length);
966 /*
967 * Step 4: Update MD5 hash with shared secret.
968 */
969 MD5_Update(&ctx, ndo->ndo_sigsecret, strlen(ndo->ndo_sigsecret));
970 MD5_Final(sig, &ctx);
971
972 if (memcmp(rcvsig, sig, TCP_SIGLEN) == 0)
973 return (SIGNATURE_VALID);
974 else
975 return (SIGNATURE_INVALID);
976 }
977 DIAG_ON_DEPRECATION
978 #endif /* HAVE_LIBCRYPTO */
979