1 /* $NetBSD: print-tcp.c,v 1.9 2007/07/26 18:15:12 plunky Exp $ */
4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
5 * The Regents of the University of California. All rights reserved.
7 * Copyright (c) 1999-2004 The tcpdump.org project
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
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.
26 /* \summary: TCP printer */
30 __RCSID("$NetBSD: print-tcp.c,v 1.8 2007/07/24 11:53:48 drochner Exp $");
37 #include <netdissect-stdinc.h>
42 #include "netdissect.h"
43 #include "addrtoname.h"
55 #include <openssl/md5.h>
56 #include "signature.h"
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
);
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
);
67 #define MAX_RST_DATA_LEN 30
77 struct tcp_seq_hash
*nxt
;
89 struct tcp_seq_hash6
{
90 struct tcp_seq_hash6
*nxt
;
96 #define TSEQ_HASHSIZE 919
98 /* These tcp optinos do not have the size octet */
99 #define ZEROLENOPT(o) ((o) == TCPOPT_EOL || (o) == TCPOPT_NOP)
101 static struct tcp_seq_hash tcp_seq_hash4
[TSEQ_HASHSIZE
];
102 static struct tcp_seq_hash6 tcp_seq_hash6
[TSEQ_HASHSIZE
];
104 static const struct tok tcp_flag_values
[] = {
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" },
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" },
140 tcp_cksum(netdissect_options
*ndo
,
141 register const struct ip
*ip
,
142 register const struct tcphdr
*tp
,
145 return nextproto4_cksum(ndo
, ip
, (const uint8_t *)tp
, len
, len
,
150 tcp6_cksum(netdissect_options
*ndo
,
151 register const struct ip6_hdr
*ip6
,
152 register const struct tcphdr
*tp
,
155 return nextproto6_cksum(ndo
, ip6
, (const uint8_t *)tp
, len
, len
,
160 tcp_print(netdissect_options
*ndo
,
161 register const u_char
*bp
, register u_int length
,
162 register const u_char
*bp2
, int fragmented
)
164 register const struct tcphdr
*tp
;
165 register const struct ip
*ip
;
166 register u_char flags
;
169 uint16_t sport
, dport
, win
, urp
;
170 uint32_t seq
, ack
, thseq
, thack
;
174 register const struct ip6_hdr
*ip6
;
176 tp
= (const struct tcphdr
*)bp
;
177 ip
= (const struct ip
*)bp2
;
179 ip6
= (const struct ip6_hdr
*)bp2
;
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
)));
190 sport
= EXTRACT_16BITS(&tp
->th_sport
);
191 dport
= EXTRACT_16BITS(&tp
->th_dport
);
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
)));
201 ND_PRINT((ndo
, "%s > %s: ",
202 tcpport_string(ndo
, sport
), tcpport_string(ndo
, dport
)));
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
)));
212 ND_PRINT((ndo
, "%s > %s: ",
213 tcpport_string(ndo
, sport
), tcpport_string(ndo
, dport
)));
219 hlen
= TH_OFF(tp
) * 4;
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
)));
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
);
232 if (ndo
->ndo_qflag
) {
233 ND_PRINT((ndo
, "tcp %d", length
- hlen
));
235 ND_PRINT((ndo
, " [bad hdr length %u - too long, > %u]",
241 flags
= tp
->th_flags
;
242 ND_PRINT((ndo
, "Flags [%s]", bittok2str_nosep(tcp_flag_values
, "none", flags
)));
244 if (!ndo
->ndo_Sflag
&& (flags
& TH_ACK
)) {
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
253 register struct tcp_seq_hash6
*th
;
254 struct tcp_seq_hash6
*tcp_seq_hash
;
255 const struct in6_addr
*src
, *dst
;
258 tcp_seq_hash
= tcp_seq_hash6
;
263 else if (sport
== dport
) {
264 if (UNALIGNED_MEMCMP(src
, dst
, sizeof ip6
->ip6_dst
) > 0)
268 UNALIGNED_MEMCPY(&tha
.src
, dst
, sizeof ip6
->ip6_dst
);
269 UNALIGNED_MEMCPY(&tha
.dst
, src
, sizeof ip6
->ip6_src
);
270 tha
.port
= dport
<< 16 | sport
;
272 UNALIGNED_MEMCPY(&tha
.dst
, dst
, sizeof ip6
->ip6_dst
);
273 UNALIGNED_MEMCPY(&tha
.src
, src
, sizeof ip6
->ip6_src
);
274 tha
.port
= sport
<< 16 | dport
;
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)
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
));
289 (*ndo
->ndo_error
)(ndo
,
290 "tcp_print: calloc");
294 th
->ack
= seq
, th
->seq
= ack
- 1;
296 th
->seq
= seq
, th
->ack
= ack
- 1;
299 seq
-= th
->ack
, ack
-= th
->seq
;
301 seq
-= th
->seq
, ack
-= th
->ack
;
307 register struct tcp_seq_hash
*th
;
308 struct tcp_seq_hash
*tcp_seq_hash
;
311 tcp_seq_hash
= tcp_seq_hash4
;
314 else if (sport
== dport
) {
315 if (UNALIGNED_MEMCMP(&ip
->ip_src
, &ip
->ip_dst
, sizeof ip
->ip_dst
) > 0)
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
= dport
<< 16 | sport
;
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
= sport
<< 16 | dport
;
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)
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
));
340 (*ndo
->ndo_error
)(ndo
,
341 "tcp_print: calloc");
345 th
->ack
= seq
, th
->seq
= ack
- 1;
347 th
->seq
= seq
, th
->ack
= ack
- 1;
350 seq
-= th
->ack
, ack
-= th
->seq
;
352 seq
-= th
->seq
, ack
-= th
->ack
;
360 thseq
= thack
= rev
= 0;
363 ND_PRINT((ndo
, " [bad hdr length %u - too long, > %u]",
368 if (ndo
->ndo_vflag
&& !ndo
->ndo_Kflag
&& !fragmented
) {
369 /* Check the checksum, if possible. */
370 uint16_t sum
, tcp_sum
;
373 if (ND_TTEST2(tp
->th_sport
, length
)) {
374 sum
= tcp_cksum(ndo
, ip
, tp
, length
);
375 tcp_sum
= EXTRACT_16BITS(&tp
->th_sum
);
377 ND_PRINT((ndo
, ", cksum 0x%04x", tcp_sum
));
379 ND_PRINT((ndo
, " (incorrect -> 0x%04x)",
380 in_cksum_shouldbe(tcp_sum
, sum
)));
382 ND_PRINT((ndo
, " (correct)"));
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
);
389 ND_PRINT((ndo
, ", cksum 0x%04x", tcp_sum
));
391 ND_PRINT((ndo
, " (incorrect -> 0x%04x)",
392 in_cksum_shouldbe(tcp_sum
, sum
)));
394 ND_PRINT((ndo
, " (correct)"));
401 if (ndo
->ndo_vflag
> 1 || length
> 0 || flags
& (TH_SYN
| TH_FIN
| TH_RST
)) {
402 ND_PRINT((ndo
, ", seq %u", seq
));
405 ND_PRINT((ndo
, ":%u", seq
+ length
));
409 if (flags
& TH_ACK
) {
410 ND_PRINT((ndo
, ", ack %u", ack
));
413 ND_PRINT((ndo
, ", win %d", win
));
416 ND_PRINT((ndo
, ", urg %d", urp
));
418 * Handle any options.
420 if (hlen
> sizeof(*tp
)) {
421 register const u_char
*cp
;
422 register u_int i
, opt
, datalen
;
426 cp
= (const u_char
*)tp
+ sizeof(*tp
);
427 ND_PRINT((ndo
, ", options ["));
430 ND_PRINT((ndo
, "%c", ch
));
437 len
= *cp
++; /* total including type, len */
438 if (len
< 2 || len
> hlen
)
440 --hlen
; /* account for length byte */
442 --hlen
; /* account for type byte */
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); }
449 ND_PRINT((ndo
, "%s", tok2str(tcp_option_values
, "unknown-%u", opt
)));
456 ND_PRINT((ndo
, " %u", EXTRACT_16BITS(cp
)));
462 ND_PRINT((ndo
, " %u", *cp
));
467 if (datalen
% 8 != 0) {
468 ND_PRINT((ndo
, " invalid sack"));
472 ND_PRINT((ndo
, " %d ", datalen
/ 8));
473 for (i
= 0; i
< datalen
; i
+= 8) {
475 s
= EXTRACT_32BITS(cp
+ i
);
477 e
= EXTRACT_32BITS(cp
+ i
+ 4);
485 ND_PRINT((ndo
, "{%u:%u}", s
, e
));
494 case TCPOPT_ECHOREPLY
:
497 * those options share their semantics.
502 ND_PRINT((ndo
, " %u", EXTRACT_32BITS(cp
)));
505 case TCPOPT_TIMESTAMP
:
508 ND_PRINT((ndo
, " val %u ecr %u",
510 EXTRACT_32BITS(cp
+ 4)));
513 case TCPOPT_SIGNATURE
:
514 datalen
= TCP_SIGLEN
;
516 ND_PRINT((ndo
, " "));
517 #ifdef HAVE_LIBCRYPTO
518 switch (tcp_verify_signature(ndo
, ip
, tp
,
519 bp
+ TH_OFF(tp
) * 4, length
, cp
)) {
521 case SIGNATURE_VALID
:
522 ND_PRINT((ndo
, "valid"));
525 case SIGNATURE_INVALID
:
526 ND_PRINT((ndo
, "invalid"));
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
]));
536 for (i
= 0; i
< TCP_SIGLEN
; ++i
)
537 ND_PRINT((ndo
, "%02x", cp
[i
]));
544 ND_PRINT((ndo
, " cap %02x id %u", cp
[0], cp
[1]));
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
555 ND_PRINT((ndo
, " invalid"));
558 ND_PRINT((ndo
, " keyid %u", cp
[0]));
560 ND_PRINT((ndo
, " rnextkeyid %u", cp
[1]));
562 ND_PRINT((ndo
, " mac 0x"));
563 for (i
= 2; i
< datalen
; i
++) {
565 ND_PRINT((ndo
, "%02x", cp
[i
]));
575 * Nothing interesting.
583 utoval
= EXTRACT_16BITS(cp
);
584 ND_PRINT((ndo
, " 0x%x", utoval
));
586 utoval
= (utoval
>> 1) * 60;
589 ND_PRINT((ndo
, " %u", utoval
));
595 if (!mptcp_print(ndo
, cp
-2, len
, flags
))
599 case TCPOPT_FASTOPEN
:
602 ND_PRINT((ndo
, " "));
603 print_tcp_fastopen_option(ndo
, cp
, datalen
, FALSE
);
606 case TCPOPT_EXPERIMENT2
:
612 magic
= EXTRACT_16BITS(cp
);
613 ND_PRINT((ndo
, "-"));
617 case 0xf989: /* TCP Fast Open RFC 7413 */
618 print_tcp_fastopen_option(ndo
, cp
+ 2, datalen
- 2, TRUE
);
622 /* Unknown magic number */
623 ND_PRINT((ndo
, "%04x", magic
));
631 ND_PRINT((ndo
, " 0x"));
632 for (i
= 0; i
< datalen
; ++i
) {
634 ND_PRINT((ndo
, "%02x", cp
[i
]));
639 /* Account for data printed */
643 /* Check specification against observed length */
644 ++datalen
; /* option octet */
645 if (!ZEROLENOPT(opt
))
646 ++datalen
; /* size octet */
648 ND_PRINT((ndo
, "[len %d]", len
));
650 if (opt
== TCPOPT_EOL
)
653 ND_PRINT((ndo
, "]"));
657 * Print length field before crawling down the stack.
659 ND_PRINT((ndo
, ", length %u", length
));
665 * Decode payload if necessary.
667 bp
+= TH_OFF(tp
) * 4;
668 if ((flags
& TH_RST
) && ndo
->ndo_vflag
) {
669 print_tcp_rst_data(ndo
, bp
, length
);
673 if (ndo
->ndo_packettype
) {
674 switch (ndo
->ndo_packettype
) {
676 zmtp1_print(ndo
, bp
, length
);
679 resp_print(ndo
, bp
, length
);
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
))
694 else if (IS_SRC_OR_DST_PORT(REDIS_PORT
))
695 resp_print(ndo
, bp
, length
);
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
);
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
))) {
718 * TCP DNS query has 2byte length at the head.
719 * XXX packet could be unaligned, it can go strange
721 ns_print(ndo
, bp
+ 2, length
- 2, 0);
722 } else if (IS_SRC_OR_DST_PORT(MSDP_PORT
)) {
723 msdp_print(ndo
, bp
, length
);
724 } else if (IS_SRC_OR_DST_PORT(RPKI_RTR_PORT
)) {
725 rpki_rtr_print(ndo
, bp
, length
);
727 else if (length
> 0 && (IS_SRC_OR_DST_PORT(LDP_PORT
))) {
728 ldp_print(ndo
, bp
, length
);
730 else if ((IS_SRC_OR_DST_PORT(NFS_PORT
)) &&
731 length
>= 4 && ND_TTEST2(*bp
, 4)) {
733 * If data present, header length valid, and NFS port used,
735 * Pass offset of data plus 4 bytes for RPC TCP msg length
736 * to NFS print routines.
739 register const struct sunrpc_msg
*rp
;
740 enum sunrpc_msg_type direction
;
742 fraglen
= EXTRACT_32BITS(bp
) & 0x7FFFFFFF;
743 if (fraglen
> (length
) - 4)
744 fraglen
= (length
) - 4;
745 rp
= (const struct sunrpc_msg
*)(bp
+ 4);
746 if (ND_TTEST(rp
->rm_direction
)) {
747 direction
= (enum sunrpc_msg_type
)EXTRACT_32BITS(&rp
->rm_direction
);
748 if (dport
== NFS_PORT
&& direction
== SUNRPC_CALL
) {
749 ND_PRINT((ndo
, ": NFS request xid %u ", EXTRACT_32BITS(&rp
->rm_xid
)));
750 nfsreq_print_noaddr(ndo
, (const u_char
*)rp
, fraglen
, (const u_char
*)ip
);
753 if (sport
== NFS_PORT
&& direction
== SUNRPC_REPLY
) {
754 ND_PRINT((ndo
, ": NFS reply xid %u ", EXTRACT_32BITS(&rp
->rm_xid
)));
755 nfsreply_print_noaddr(ndo
, (const u_char
*)rp
, fraglen
, (const u_char
*)ip
);
763 ND_PRINT((ndo
, "[bad opt]"));
765 ND_PRINT((ndo
, ">"));
768 ND_PRINT((ndo
, "[|tcp]"));
770 ND_PRINT((ndo
, ">"));
774 * RFC1122 says the following on data in RST segments:
776 * 4.2.2.12 RST Segment: RFC-793 Section 3.4
778 * A TCP SHOULD allow a received RST segment to include data.
781 * It has been suggested that a RST segment could contain
782 * ASCII text that encoded and explained the cause of the
783 * RST. No standard has yet been established for such
789 print_tcp_rst_data(netdissect_options
*ndo
,
790 register const u_char
*sp
, u_int length
)
794 ND_PRINT((ndo
, ND_TTEST2(*sp
, length
) ? " [RST" : " [!RST"));
795 if (length
> MAX_RST_DATA_LEN
) {
796 length
= MAX_RST_DATA_LEN
; /* can use -X for longer */
797 ND_PRINT((ndo
, "+")); /* indicate we truncate */
799 ND_PRINT((ndo
, " "));
800 while (length
-- && sp
< ndo
->ndo_snapend
) {
804 ND_PRINT((ndo
, "]"));
808 print_tcp_fastopen_option(netdissect_options
*ndo
, register const u_char
*cp
,
809 u_int datalen
, int exp
)
814 ND_PRINT((ndo
, "tfo"));
817 /* Fast Open Cookie Request */
818 ND_PRINT((ndo
, " cookiereq"));
820 /* Fast Open Cookie */
821 if (datalen
% 2 != 0 || datalen
< 4 || datalen
> 16) {
822 ND_PRINT((ndo
, " invalid"));
824 ND_PRINT((ndo
, " cookie "));
825 for (i
= 0; i
< datalen
; ++i
)
826 ND_PRINT((ndo
, "%02x", cp
[i
]));
831 #ifdef HAVE_LIBCRYPTO
832 USES_APPLE_DEPRECATED_API
834 tcp_verify_signature(netdissect_options
*ndo
,
835 const struct ip
*ip
, const struct tcphdr
*tp
,
836 const u_char
*data
, int length
, const u_char
*rcvsig
)
839 u_char sig
[TCP_SIGLEN
];
842 uint16_t savecsum
, tlen
;
843 const struct ip6_hdr
*ip6
;
847 if (data
+ length
> ndo
->ndo_snapend
) {
848 ND_PRINT((ndo
, "snaplen too short, "));
849 return (CANT_CHECK_SIGNATURE
);
854 if (ndo
->ndo_sigsecret
== NULL
) {
855 ND_PRINT((ndo
, "shared secret not supplied with -M, "));
856 return (CANT_CHECK_SIGNATURE
);
861 * Step 1: Update MD5 hash with IP pseudo-header.
864 MD5_Update(&ctx
, (const char *)&ip
->ip_src
, sizeof(ip
->ip_src
));
865 MD5_Update(&ctx
, (const char *)&ip
->ip_dst
, sizeof(ip
->ip_dst
));
866 MD5_Update(&ctx
, (const char *)&zero_proto
, sizeof(zero_proto
));
867 MD5_Update(&ctx
, (const char *)&ip
->ip_p
, sizeof(ip
->ip_p
));
868 tlen
= EXTRACT_16BITS(&ip
->ip_len
) - IP_HL(ip
) * 4;
870 MD5_Update(&ctx
, (const char *)&tlen
, sizeof(tlen
));
871 } else if (IP_V(ip
) == 6) {
872 ip6
= (const struct ip6_hdr
*)ip
;
873 MD5_Update(&ctx
, (const char *)&ip6
->ip6_src
, sizeof(ip6
->ip6_src
));
874 MD5_Update(&ctx
, (const char *)&ip6
->ip6_dst
, sizeof(ip6
->ip6_dst
));
875 len32
= htonl(EXTRACT_16BITS(&ip6
->ip6_plen
));
876 MD5_Update(&ctx
, (const char *)&len32
, sizeof(len32
));
878 MD5_Update(&ctx
, (const char *)&nxt
, sizeof(nxt
));
879 MD5_Update(&ctx
, (const char *)&nxt
, sizeof(nxt
));
880 MD5_Update(&ctx
, (const char *)&nxt
, sizeof(nxt
));
882 MD5_Update(&ctx
, (const char *)&nxt
, sizeof(nxt
));
884 ND_PRINT((ndo
, "IP version not 4 or 6, "));
885 return (CANT_CHECK_SIGNATURE
);
889 * Step 2: Update MD5 hash with TCP header, excluding options.
890 * The TCP checksum must be set to zero.
892 savecsum
= tp1
.th_sum
;
894 MD5_Update(&ctx
, (const char *)&tp1
, sizeof(struct tcphdr
));
895 tp1
.th_sum
= savecsum
;
897 * Step 3: Update MD5 hash with TCP segment data, if present.
900 MD5_Update(&ctx
, data
, length
);
902 * Step 4: Update MD5 hash with shared secret.
904 MD5_Update(&ctx
, ndo
->ndo_sigsecret
, strlen(ndo
->ndo_sigsecret
));
905 MD5_Final(sig
, &ctx
);
907 if (memcmp(rcvsig
, sig
, TCP_SIGLEN
) == 0)
908 return (SIGNATURE_VALID
);
910 return (SIGNATURE_INVALID
);
913 #endif /* HAVE_LIBCRYPTO */
917 * c-style: whitesmith