xref: /freebsd/contrib/tcpdump/print-ah.c (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1 /*	$NetBSD: print-ah.c,v 1.4 1996/05/20 00:41:16 fvdl Exp $	*/
2 
3 /*
4  * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that: (1) source code distributions
9  * retain the above copyright notice and this paragraph in its entirety, (2)
10  * distributions including binary code include the above copyright notice and
11  * this paragraph in its entirety in the documentation or other materials
12  * provided with the distribution, and (3) all advertising materials mentioning
13  * features or use of this software display the following acknowledgement:
14  * ``This product includes software developed by the University of California,
15  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16  * the University nor the names of its contributors may be used to endorse
17  * or promote products derived from this software without specific prior
18  * written permission.
19  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22  */
23 
24 /* \summary: IPSEC Authentication Header printer */
25 
26 #ifdef HAVE_CONFIG_H
27 #include <config.h>
28 #endif
29 
30 #include "netdissect-stdinc.h"
31 
32 #include "netdissect.h"
33 #include "extract.h"
34 
35 #include "ah.h"
36 
37 int
38 ah_print(netdissect_options *ndo, const u_char *bp)
39 {
40 	const struct ah *ah;
41 	uint8_t ah_len;
42 	u_int ah_hdr_len;
43 	uint16_t reserved;
44 	const u_char *p;
45 
46 	ndo->ndo_protocol = "ah";
47 	ah = (const struct ah *)bp;
48 
49 	nd_print_protocol_caps(ndo);
50 /*
51  * RFC4302
52  *
53  * 2.2.  Payload Length
54  *
55  *    This 8-bit field specifies the length of AH in 32-bit words (4-byte
56  *    units), minus "2".
57  */
58 	ah_len = GET_U_1(ah->ah_len);
59 	ah_hdr_len = (ah_len + 2) * 4;
60 
61 	ND_PRINT("(");
62 	if (ndo->ndo_vflag)
63 		ND_PRINT("length=%u(%u-bytes),", ah_len, ah_hdr_len);
64 	reserved = GET_BE_U_2(ah->ah_reserved);
65 	if (reserved)
66 		ND_PRINT("reserved=0x%x[MustBeZero],", reserved);
67 	ND_PRINT("spi=0x%08x,", GET_BE_U_4(ah->ah_spi));
68 	ND_PRINT("seq=0x%x,", GET_BE_U_4(ah->ah_seq));
69 	ND_PRINT("icv=0x");
70 	for (p = (const u_char *)(ah + 1); p < bp + ah_hdr_len; p++)
71 		ND_PRINT("%02x", GET_U_1(p));
72 	ND_PRINT("): ");
73 
74 	return ah_hdr_len;
75 }
76