xref: /netbsd-src/external/bsd/tcpdump/dist/print-ah.c (revision ccd9df534e375a4366c5b55f23782053c7a98d82)
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 #include <sys/cdefs.h>
25 #ifndef lint
26 __RCSID("$NetBSD: print-ah.c,v 1.8 2023/08/17 20:19:40 christos Exp $");
27 #endif
28 
29 /* \summary: IPSEC Authentication Header printer */
30 
31 #ifdef HAVE_CONFIG_H
32 #include <config.h>
33 #endif
34 
35 #include "netdissect-stdinc.h"
36 
37 #include "netdissect.h"
38 #include "extract.h"
39 
40 #include "ah.h"
41 
42 int
43 ah_print(netdissect_options *ndo, const u_char *bp)
44 {
45 	const struct ah *ah;
46 	uint8_t ah_len;
47 	u_int ah_hdr_len;
48 	uint16_t reserved;
49 	const u_char *p;
50 
51 	ndo->ndo_protocol = "ah";
52 	ah = (const struct ah *)bp;
53 
54 	nd_print_protocol_caps(ndo);
55 /*
56  * RFC4302
57  *
58  * 2.2.  Payload Length
59  *
60  *    This 8-bit field specifies the length of AH in 32-bit words (4-byte
61  *    units), minus "2".
62  */
63 	ah_len = GET_U_1(ah->ah_len);
64 	ah_hdr_len = (ah_len + 2) * 4;
65 
66 	ND_PRINT("(");
67 	if (ndo->ndo_vflag)
68 		ND_PRINT("length=%u(%u-bytes),", ah_len, ah_hdr_len);
69 	reserved = GET_BE_U_2(ah->ah_reserved);
70 	if (reserved)
71 		ND_PRINT("reserved=0x%x[MustBeZero],", reserved);
72 	ND_PRINT("spi=0x%08x,", GET_BE_U_4(ah->ah_spi));
73 	ND_PRINT("seq=0x%x,", GET_BE_U_4(ah->ah_seq));
74 	ND_PRINT("icv=0x");
75 	for (p = (const u_char *)(ah + 1); p < bp + ah_hdr_len; p++)
76 		ND_PRINT("%02x", GET_U_1(p));
77 	ND_PRINT("): ");
78 
79 	return ah_hdr_len;
80 }
81