1 /* $NetBSD: nd6_rtr.c,v 1.149 2020/06/12 11:04:45 roy Exp $ */
2 /* $KAME: nd6_rtr.c,v 1.95 2001/02/07 08:09:47 itojun Exp $ */
3
4 /*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #include <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: nd6_rtr.c,v 1.149 2020/06/12 11:04:45 roy Exp $");
35
36 #ifdef _KERNEL_OPT
37 #include "opt_net_mpsafe.h"
38 #endif
39
40 #include <sys/mbuf.h>
41 #include <sys/syslog.h>
42
43 #include <net/if.h>
44
45 #include <netinet/in.h>
46 #include <netinet6/in6_var.h>
47 #include <netinet/ip6.h>
48 #include <netinet6/nd6.h>
49 #include <netinet/icmp6.h>
50 #include <netinet6/icmp6_private.h>
51
52 /*
53 * Cache the source link layer address of Router Advertisement
54 * and Solicition messages.
55 */
56 void
nd6_rtr_cache(struct mbuf * m,int off,int icmp6len,int icmp6_type)57 nd6_rtr_cache(struct mbuf *m, int off, int icmp6len, int icmp6_type)
58 {
59 struct ifnet *ifp;
60 struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
61 struct nd_router_solicit *nd_rs;
62 struct nd_router_advert *nd_ra;
63 struct in6_addr saddr6 = ip6->ip6_src;
64 char *lladdr = NULL;
65 int lladdrlen = 0;
66 union nd_opts ndopts;
67 struct psref psref;
68 char ip6bufs[INET6_ADDRSTRLEN], ip6bufd[INET6_ADDRSTRLEN];
69
70 ifp = m_get_rcvif_psref(m, &psref);
71 if (ifp == NULL)
72 goto freeit;
73
74 /* Sanity checks */
75 if (ip6->ip6_hlim != 255) {
76 nd6log(LOG_ERR, "invalid hlim (%d) from %s to %s on %s\n",
77 ip6->ip6_hlim, IN6_PRINT(ip6bufs, &ip6->ip6_src),
78 IN6_PRINT(ip6bufd, &ip6->ip6_dst), if_name(ifp));
79 goto bad;
80 }
81
82 switch (icmp6_type) {
83 case ND_ROUTER_SOLICIT:
84 /*
85 * Don't update the neighbor cache, if src = ::.
86 * This indicates that the src has no IP address assigned yet.
87 */
88 if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
89 goto freeit;
90
91 IP6_EXTHDR_GET(nd_rs, struct nd_router_solicit *, m, off,
92 icmp6len);
93 if (nd_rs == NULL) {
94 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
95 m_put_rcvif_psref(ifp, &psref);
96 return;
97 }
98
99 icmp6len -= sizeof(*nd_rs);
100 nd6_option_init(nd_rs + 1, icmp6len, &ndopts);
101 break;
102 case ND_ROUTER_ADVERT:
103 if (!IN6_IS_ADDR_LINKLOCAL(&saddr6)) {
104 nd6log(LOG_ERR, "src %s is not link-local\n",
105 IN6_PRINT(ip6bufs, &saddr6));
106 goto bad;
107 }
108
109 IP6_EXTHDR_GET(nd_ra, struct nd_router_advert *, m, off,
110 icmp6len);
111 if (nd_ra == NULL) {
112 ICMP6_STATINC(ICMP6_STAT_TOOSHORT);
113 m_put_rcvif_psref(ifp, &psref);
114 return;
115 }
116
117 icmp6len -= sizeof(*nd_ra);
118 nd6_option_init(nd_ra + 1, icmp6len, &ndopts);
119 break;
120 }
121
122 if (nd6_options(&ndopts) < 0) {
123 nd6log(LOG_INFO, "invalid ND option, ignored\n");
124 /* nd6_options have incremented stats */
125 goto freeit;
126 }
127
128 if (ndopts.nd_opts_src_lladdr) {
129 lladdr = (char *)(ndopts.nd_opts_src_lladdr + 1);
130 lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
131 }
132
133 if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
134 nd6log(LOG_INFO, "lladdrlen mismatch for %s "
135 "(if %d, %s packet %d)\n",
136 IN6_PRINT(ip6bufs, &saddr6),
137 ifp->if_addrlen,
138 icmp6_type == ND_ROUTER_SOLICIT ? "RS" : "RA",
139 lladdrlen - 2);
140 goto bad;
141 }
142
143 nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, icmp6_type, 0);
144
145 freeit:
146 m_put_rcvif_psref(ifp, &psref);
147 m_freem(m);
148 return;
149
150 bad:
151 ICMP6_STATINC(icmp6_type == ND_ROUTER_SOLICIT ?
152 ICMP6_STAT_BADRS : ICMP6_STAT_BADRA);
153 m_put_rcvif_psref(ifp, &psref);
154 m_freem(m);
155 }
156