util.c revision 1.1 
1/*	$OpenBSD: util.c,v 1.1 2012/10/21 21:30:44 bluhm Exp $ */
2
3/*
4 * Copyright (c) 2012 Alexander Bluhm <bluhm@openbsd.org>
5 * Copyright (c) 2004 Esben Norby <norby@openbsd.org>
6 * Copyright (c) 2003, 2004 Henning Brauer <henning@openbsd.org>
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 */
20
21#include <netinet/in.h>
22#include <string.h>
23
24#include "ospf6d.h"
25#include "log.h"
26
27#define IN6_IS_SCOPE_EMBED(a)   \
28	((IN6_IS_ADDR_LINKLOCAL(a)) ||  \
29	 (IN6_IS_ADDR_MC_LINKLOCAL(a)) || \
30	 (IN6_IS_ADDR_MC_INTFACELOCAL(a)))
31
32void
33embedscope(struct sockaddr_in6 *sin6)
34{
35	u_int16_t	 tmp16;
36
37	if (IN6_IS_SCOPE_EMBED(&sin6->sin6_addr)) {
38		bcopy(&sin6->sin6_addr.s6_addr[2], &tmp16, sizeof(tmp16));
39		if (tmp16 != 0) {
40			log_warnx("embedscope: address %s already has embeded "
41			    "scope %u", log_sockaddr(sin6), ntohs(tmp16));
42		}
43		tmp16 = htons(sin6->sin6_scope_id);
44		bcopy(&tmp16, &sin6->sin6_addr.s6_addr[2], sizeof(tmp16));
45		sin6->sin6_scope_id = 0;
46	}
47}
48
49void
50recoverscope(struct sockaddr_in6 *sin6)
51{
52	u_int16_t	 tmp16;
53
54	if (sin6->sin6_scope_id != 0) {
55		log_warnx("recoverscope: address %s already has scope id %u",
56		    log_sockaddr(sin6), sin6->sin6_scope_id);
57	}
58
59	if (IN6_IS_SCOPE_EMBED(&sin6->sin6_addr)) {
60		bcopy(&sin6->sin6_addr.s6_addr[2], &tmp16, sizeof(tmp16));
61		sin6->sin6_scope_id = ntohs(tmp16);
62		sin6->sin6_addr.s6_addr[2] = 0;
63		sin6->sin6_addr.s6_addr[3] = 0;
64	}
65}
66
67void
68clearscope(struct in6_addr *in6)
69{
70	if (IN6_IS_SCOPE_EMBED(in6)) {
71		in6->s6_addr[2] = 0;
72		in6->s6_addr[3] = 0;
73	}
74}
75
76#undef IN6_IS_SCOPE_EMBED
77
78u_int8_t
79mask2prefixlen(struct sockaddr_in6 *sa_in6)
80{
81	u_int8_t	l = 0, *ap, *ep;
82
83	/*
84	 * sin6_len is the size of the sockaddr so substract the offset of
85	 * the possibly truncated sin6_addr struct.
86	 */
87	ap = (u_int8_t *)&sa_in6->sin6_addr;
88	ep = (u_int8_t *)sa_in6 + sa_in6->sin6_len;
89	for (; ap < ep; ap++) {
90		/* this "beauty" is adopted from sbin/route/show.c ... */
91		switch (*ap) {
92		case 0xff:
93			l += 8;
94			break;
95		case 0xfe:
96			l += 7;
97			return (l);
98		case 0xfc:
99			l += 6;
100			return (l);
101		case 0xf8:
102			l += 5;
103			return (l);
104		case 0xf0:
105			l += 4;
106			return (l);
107		case 0xe0:
108			l += 3;
109			return (l);
110		case 0xc0:
111			l += 2;
112			return (l);
113		case 0x80:
114			l += 1;
115			return (l);
116		case 0x00:
117			return (l);
118		default:
119			fatalx("non contiguous inet6 netmask");
120		}
121	}
122
123	return (l);
124}
125
126struct in6_addr *
127prefixlen2mask(u_int8_t prefixlen)
128{
129	static struct in6_addr	mask;
130	int			i;
131
132	bzero(&mask, sizeof(mask));
133	for (i = 0; i < prefixlen / 8; i++)
134		mask.s6_addr[i] = 0xff;
135	i = prefixlen % 8;
136	if (i)
137		mask.s6_addr[prefixlen / 8] = 0xff00 >> i;
138
139	return (&mask);
140}
141
142void
143inet6applymask(struct in6_addr *dest, const struct in6_addr *src, int prefixlen)
144{
145	struct in6_addr	mask;
146	int		i;
147
148	bzero(&mask, sizeof(mask));
149	for (i = 0; i < prefixlen / 8; i++)
150		mask.s6_addr[i] = 0xff;
151	i = prefixlen % 8;
152	if (i)
153		mask.s6_addr[prefixlen / 8] = 0xff00 >> i;
154
155	for (i = 0; i < 16; i++)
156		dest->s6_addr[i] = src->s6_addr[i] & mask.s6_addr[i];
157}
158