xref: /freebsd/sys/netinet6/dest6.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/malloc.h>
41 #include <sys/mbuf.h>
42 #include <sys/domain.h>
43 #include <sys/protosw.h>
44 #include <sys/socket.h>
45 #include <sys/errno.h>
46 #include <sys/time.h>
47 #include <sys/kernel.h>
48 
49 #include <net/if.h>
50 #include <net/if_var.h>
51 #include <net/route.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_var.h>
55 #include <netinet/ip6.h>
56 #include <netinet6/ip6_var.h>
57 #include <netinet/icmp6.h>
58 
59 /*
60  * Destination options header processing.
61  */
62 int
63 dest6_input(struct mbuf **mp, int *offp, int proto)
64 {
65 	struct mbuf *m;
66 	int off, dstoptlen, optlen;
67 	struct ip6_dest *dstopts;
68 	u_int8_t *opt;
69 
70 	m = *mp;
71 	off = *offp;
72 
73 	/* Validation of the length of the header. */
74 	if (m->m_len < off + sizeof(*dstopts)) {
75 		m = m_pullup(m, off + sizeof(*dstopts));
76 		if (m == NULL) {
77 			IP6STAT_INC(ip6s_exthdrtoolong);
78 			*mp = m;
79 			return (IPPROTO_DONE);
80 		}
81 	}
82 	dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
83 	dstoptlen = (dstopts->ip6d_len + 1) << 3;
84 
85 	if (m->m_len < off + dstoptlen) {
86 		m = m_pullup(m, off + dstoptlen);
87 		if (m == NULL) {
88 			IP6STAT_INC(ip6s_exthdrtoolong);
89 			*mp = m;
90 			return (IPPROTO_DONE);
91 		}
92 	}
93 	dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);
94 	off += dstoptlen;
95 	dstoptlen -= sizeof(struct ip6_dest);
96 	opt = (u_int8_t *)dstopts + sizeof(struct ip6_dest);
97 
98 	/* search header for all options. */
99 	for (; dstoptlen > 0; dstoptlen -= optlen, opt += optlen) {
100 		if (*opt != IP6OPT_PAD1 &&
101 		    (dstoptlen < IP6OPT_MINLEN || *(opt + 1) + 2 > dstoptlen)) {
102 			IP6STAT_INC(ip6s_toosmall);
103 			goto bad;
104 		}
105 
106 		switch (*opt) {
107 		case IP6OPT_PAD1:
108 			optlen = 1;
109 			break;
110 		case IP6OPT_PADN:
111 			optlen = *(opt + 1) + 2;
112 			break;
113 		default:		/* unknown option */
114 			optlen = ip6_unknown_opt(opt, m,
115 			    opt - mtod(m, u_int8_t *));
116 			if (optlen == -1) {
117 				*mp = NULL;
118 				return (IPPROTO_DONE);
119 			}
120 			optlen += 2;
121 			break;
122 		}
123 	}
124 
125 	*offp = off;
126 	*mp = m;
127 	return (dstopts->ip6d_nxt);
128 
129   bad:
130 	m_freem(m);
131 	*mp = NULL;
132 	return (IPPROTO_DONE);
133 }
134