xref: /freebsd/contrib/tcpdump/print-frag6.c (revision 2008043f386721d58158e37e0d7e50df8095942d)
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 /* \summary: IPv6 fragmentation header printer */
23 
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27 
28 #include "netdissect-stdinc.h"
29 
30 #include "netdissect.h"
31 #include "extract.h"
32 
33 #include "ip6.h"
34 
35 int
36 frag6_print(netdissect_options *ndo, const u_char *bp, const u_char *bp2)
37 {
38 	const struct ip6_frag *dp;
39 	const struct ip6_hdr *ip6;
40 
41 	ndo->ndo_protocol = "frag6";
42 	dp = (const struct ip6_frag *)bp;
43 	ip6 = (const struct ip6_hdr *)bp2;
44 
45 	if (ndo->ndo_vflag) {
46 		ND_PRINT("frag (0x%08x:%u|%zu)",
47 			 GET_BE_U_4(dp->ip6f_ident),
48 			 GET_BE_U_2(dp->ip6f_offlg) & IP6F_OFF_MASK,
49 			 sizeof(struct ip6_hdr) + GET_BE_U_2(ip6->ip6_plen) -
50 			        (bp - bp2) - sizeof(struct ip6_frag));
51 	} else {
52 		ND_PRINT("frag (%u|%zu)",
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 	}
57 
58 	/* it is meaningless to decode non-first fragment */
59 	if ((GET_BE_U_2(dp->ip6f_offlg) & IP6F_OFF_MASK) != 0)
60 		return -1;
61 	else
62 	{
63 		ND_PRINT(" ");
64 		return sizeof(struct ip6_frag);
65 	}
66 }
67