xref: /netbsd-src/external/bsd/tcpdump/dist/print-frag6.c (revision ccd9df534e375a4366c5b55f23782053c7a98d82)
1 /*
2  * Copyright (c) 1988, 1989, 1990, 1991, 1993, 1994
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that: (1) source code distributions
7  * retain the above copyright notice and this paragraph in its entirety, (2)
8  * distributions including binary code include the above copyright notice and
9  * this paragraph in its entirety in the documentation or other materials
10  * provided with the distribution, and (3) all advertising materials mentioning
11  * features or use of this software display the following acknowledgement:
12  * ``This product includes software developed by the University of California,
13  * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14  * the University nor the names of its contributors may be used to endorse
15  * or promote products derived from this software without specific prior
16  * written permission.
17  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18  * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20  */
21 
22 #include <sys/cdefs.h>
23 #ifndef lint
24 __RCSID("$NetBSD: print-frag6.c,v 1.8 2023/08/17 20:19:40 christos Exp $");
25 #endif
26 
27 /* \summary: IPv6 fragmentation header printer */
28 
29 #ifdef HAVE_CONFIG_H
30 #include <config.h>
31 #endif
32 
33 #include "netdissect-stdinc.h"
34 
35 #include "netdissect.h"
36 #include "extract.h"
37 
38 #include "ip6.h"
39 
40 int
41 frag6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2)
42 {
43 	const struct ip6_frag *dp;
44 	const struct ip6_hdr *ip6;
45 
46 	ndo->ndo_protocol = "frag6";
47 	dp = (const struct ip6_frag *)bp;
48 	ip6 = (const struct ip6_hdr *)bp2;
49 
50 	if (ndo->ndo_vflag) {
51 		ND_PRINT("frag (0x%08x:%u|%zu)",
52 			 GET_BE_U_4(dp->ip6f_ident),
53 			 GET_BE_U_2(dp->ip6f_offlg) & IP6F_OFF_MASK,
54 			 sizeof(struct ip6_hdr) + GET_BE_U_2(ip6->ip6_plen) -
55 			        (bp - bp2) - sizeof(struct ip6_frag));
56 	} else {
57 		ND_PRINT("frag (%u|%zu)",
58 		         GET_BE_U_2(dp->ip6f_offlg) & IP6F_OFF_MASK,
59 		         sizeof(struct ip6_hdr) + GET_BE_U_2(ip6->ip6_plen) -
60 			         (bp - bp2) - sizeof(struct ip6_frag));
61 	}
62 
63 	/* it is meaningless to decode non-first fragment */
64 	if ((GET_BE_U_2(dp->ip6f_offlg) & IP6F_OFF_MASK) != 0)
65 		return -1;
66 	else
67 	{
68 		ND_PRINT(" ");
69 		return sizeof(struct ip6_frag);
70 	}
71 }
72