xref: /freebsd/contrib/tcpdump/print-frag6.c (revision d4eeb02986980bf33dd56c41ceb9fc5f180c0d47)
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, register const u_char *bp, register const u_char *bp2)
37 {
38 	register const struct ip6_frag *dp;
39 	register const struct ip6_hdr *ip6;
40 
41 	dp = (const struct ip6_frag *)bp;
42 	ip6 = (const struct ip6_hdr *)bp2;
43 
44 	ND_TCHECK(*dp);
45 
46 	if (ndo->ndo_vflag) {
47 		ND_PRINT((ndo, "frag (0x%08x:%d|%ld)",
48 		       EXTRACT_32BITS(&dp->ip6f_ident),
49 		       EXTRACT_16BITS(&dp->ip6f_offlg) & IP6F_OFF_MASK,
50 		       sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen) -
51 			       (long)(bp - bp2) - sizeof(struct ip6_frag)));
52 	} else {
53 		ND_PRINT((ndo, "frag (%d|%ld)",
54 		       EXTRACT_16BITS(&dp->ip6f_offlg) & IP6F_OFF_MASK,
55 		       sizeof(struct ip6_hdr) + EXTRACT_16BITS(&ip6->ip6_plen) -
56 			       (long)(bp - bp2) - sizeof(struct ip6_frag)));
57 	}
58 
59 	/* it is meaningless to decode non-first fragment */
60 	if ((EXTRACT_16BITS(&dp->ip6f_offlg) & IP6F_OFF_MASK) != 0)
61 		return -1;
62 	else
63 	{
64 		ND_PRINT((ndo, " "));
65 		return sizeof(struct ip6_frag);
66 	}
67 trunc:
68 	ND_PRINT((ndo, "[|frag]"));
69 	return -1;
70 }
71