xref: /freebsd/sys/netinet6/dest6.c (revision 882f88ff77194ef2eea005232780468404438788)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	$KAME: dest6.c,v 1.59 2003/07/11 13:21:16 t-momose Exp $
32  */
33 
34 #include <sys/cdefs.h>
35 __FBSDID("$FreeBSD$");
36 
37 #include "opt_inet.h"
38 #include "opt_inet6.h"
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/malloc.h>
43 #include <sys/mbuf.h>
44 #include <sys/domain.h>
45 #include <sys/protosw.h>
46 #include <sys/socket.h>
47 #include <sys/errno.h>
48 #include <sys/time.h>
49 #include <sys/kernel.h>
50 
51 #include <net/if.h>
52 #include <net/if_var.h>
53 #include <net/route.h>
54 
55 #include <netinet/in.h>
56 #include <netinet/in_var.h>
57 #include <netinet/ip6.h>
58 #include <netinet6/ip6_var.h>
59 #include <netinet/icmp6.h>
60 
61 /*
62  * Destination options header processing.
63  */
64 int
65 dest6_input(struct mbuf **mp, int *offp, int proto)
66 {
67 	struct mbuf *m;
68 	int off, dstoptlen, optlen;
69 	struct ip6_dest *dstopts;
70 	u_int8_t *opt;
71 
72 	m = *mp;
73 	off = *offp;
74 
75 	/* Validation of the length of the header. */
76 	if (m->m_len < off + sizeof(*dstopts)) {
77 		m = m_pullup(m, off + sizeof(*dstopts));
78 		if (m == NULL) {
79 			IP6STAT_INC(ip6s_exthdrtoolong);
80 			*mp = m;
81 			return (IPPROTO_DONE);
82 		}
83 	}
84 	dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
85 	dstoptlen = (dstopts->ip6d_len + 1) << 3;
86 
87 	if (m->m_len < off + dstoptlen) {
88 		m = m_pullup(m, off + dstoptlen);
89 		if (m == NULL) {
90 			IP6STAT_INC(ip6s_exthdrtoolong);
91 			*mp = m;
92 			return (IPPROTO_DONE);
93 		}
94 	}
95 	dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
96 	off += dstoptlen;
97 	dstoptlen -= sizeof(struct ip6_dest);
98 	opt = (u_int8_t *)dstopts + sizeof(struct ip6_dest);
99 
100 	/* search header for all options. */
101 	for (; dstoptlen > 0; dstoptlen -= optlen, opt += optlen) {
102 		if (*opt != IP6OPT_PAD1 &&
103 		    (dstoptlen < IP6OPT_MINLEN || *(opt + 1) + 2 > dstoptlen)) {
104 			IP6STAT_INC(ip6s_toosmall);
105 			goto bad;
106 		}
107 
108 		switch (*opt) {
109 		case IP6OPT_PAD1:
110 			optlen = 1;
111 			break;
112 		case IP6OPT_PADN:
113 			optlen = *(opt + 1) + 2;
114 			break;
115 		default:		/* unknown option */
116 			optlen = ip6_unknown_opt(opt, m,
117 			    opt - mtod(m, u_int8_t *));
118 			if (optlen == -1) {
119 				*mp = NULL;
120 				return (IPPROTO_DONE);
121 			}
122 			optlen += 2;
123 			break;
124 		}
125 	}
126 
127 	*offp = off;
128 	*mp = m;
129 	return (dstopts->ip6d_nxt);
130 
131   bad:
132 	m_freem(m);
133 	*mp = NULL;
134 	return (IPPROTO_DONE);
135 }
136