xref: /freebsd/sys/netinet6/in6_gif.c (revision 3fe401a500cdfc73d8c066da3c577c4b9f0aa953)
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/lock.h>
40 #include <sys/rmlock.h>
41 #include <sys/systm.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/mbuf.h>
45 #include <sys/errno.h>
46 #include <sys/kernel.h>
47 #include <sys/queue.h>
48 #include <sys/syslog.h>
49 #include <sys/sysctl.h>
50 #include <sys/protosw.h>
51 #include <sys/malloc.h>
52 
53 #include <net/if.h>
54 #include <net/if_var.h>
55 #include <net/route.h>
56 #include <net/vnet.h>
57 
58 #include <netinet/in.h>
59 #include <netinet/in_systm.h>
60 #ifdef INET
61 #include <netinet/ip.h>
62 #endif
63 #include <netinet/ip_encap.h>
64 #ifdef INET6
65 #include <netinet/ip6.h>
66 #include <netinet6/ip6_var.h>
67 #include <netinet6/in6_var.h>
68 #endif
69 #include <netinet/ip_ecn.h>
70 #ifdef INET6
71 #include <netinet6/ip6_ecn.h>
72 #endif
73 
74 #include <net/if_gif.h>
75 
76 #define GIF_HLIM	30
77 static VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
78 #define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
79 
80 SYSCTL_DECL(_net_inet6_ip6);
81 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_VNET | CTLFLAG_RW,
82     &VNET_NAME(ip6_gif_hlim), 0, "");
83 
84 static int in6_gif_input(struct mbuf **, int *, int);
85 
86 extern  struct domain inet6domain;
87 static struct protosw in6_gif_protosw = {
88 	.pr_type =	SOCK_RAW,
89 	.pr_domain =	&inet6domain,
90 	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
91 	.pr_flags =	PR_ATOMIC|PR_ADDR,
92 	.pr_input =	in6_gif_input,
93 	.pr_output =	rip6_output,
94 	.pr_ctloutput =	rip6_ctloutput,
95 	.pr_usrreqs =	&rip6_usrreqs
96 };
97 
98 int
99 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
100 {
101 	GIF_RLOCK_TRACKER;
102 	struct gif_softc *sc = ifp->if_softc;
103 	struct ip6_hdr *ip6;
104 	int len;
105 
106 	/* prepend new IP header */
107 	len = sizeof(struct ip6_hdr);
108 #ifndef __NO_STRICT_ALIGNMENT
109 	if (proto == IPPROTO_ETHERIP)
110 		len += ETHERIP_ALIGN;
111 #endif
112 	M_PREPEND(m, len, M_NOWAIT);
113 	if (m == NULL)
114 		return (ENOBUFS);
115 #ifndef __NO_STRICT_ALIGNMENT
116 	if (proto == IPPROTO_ETHERIP) {
117 		len = mtod(m, vm_offset_t) & 3;
118 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
119 		    ("in6_gif_output: unexpected misalignment"));
120 		m->m_data += len;
121 		m->m_len -= ETHERIP_ALIGN;
122 	}
123 #endif
124 
125 	ip6 = mtod(m, struct ip6_hdr *);
126 	GIF_RLOCK(sc);
127 	if (sc->gif_family != AF_INET6) {
128 		m_freem(m);
129 		GIF_RUNLOCK(sc);
130 		return (ENETDOWN);
131 	}
132 	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
133 	GIF_RUNLOCK(sc);
134 
135 	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
136 	ip6->ip6_nxt	= proto;
137 	ip6->ip6_hlim	= V_ip6_gif_hlim;
138 	/*
139 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
140 	 * it is too painful to ask for resend of inner packet, to achieve
141 	 * path MTU discovery for encapsulated packets.
142 	 */
143 	return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
144 }
145 
146 static int
147 in6_gif_input(struct mbuf **mp, int *offp, int proto)
148 {
149 	struct mbuf *m = *mp;
150 	struct ifnet *gifp;
151 	struct gif_softc *sc;
152 	struct ip6_hdr *ip6;
153 	uint8_t ecn;
154 
155 	sc = encap_getarg(m);
156 	if (sc == NULL) {
157 		m_freem(m);
158 		IP6STAT_INC(ip6s_nogif);
159 		return (IPPROTO_DONE);
160 	}
161 	gifp = GIF2IFP(sc);
162 	if ((gifp->if_flags & IFF_UP) != 0) {
163 		ip6 = mtod(m, struct ip6_hdr *);
164 		ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
165 		m_adj(m, *offp);
166 		gif_input(m, gifp, proto, ecn);
167 	} else {
168 		m_freem(m);
169 		IP6STAT_INC(ip6s_nogif);
170 	}
171 	return (IPPROTO_DONE);
172 }
173 
174 /*
175  * we know that we are in IFF_UP, outer address available, and outer family
176  * matched the physical addr family.  see gif_encapcheck().
177  */
178 int
179 in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
180 {
181 	const struct ip6_hdr *ip6;
182 	struct gif_softc *sc;
183 	int ret;
184 
185 	/* sanity check done in caller */
186 	sc = (struct gif_softc *)arg;
187 	GIF_RLOCK_ASSERT(sc);
188 
189 	/*
190 	 * Check for address match.  Note that the check is for an incoming
191 	 * packet.  We should compare the *source* address in our configuration
192 	 * and the *destination* address of the packet, and vice versa.
193 	 */
194 	ip6 = mtod(m, const struct ip6_hdr *);
195 	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst))
196 		return (0);
197 	ret = 128;
198 	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src)) {
199 		if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0)
200 			return (0);
201 	} else
202 		ret += 128;
203 
204 	/* ingress filters on outer source */
205 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
206 		struct sockaddr_in6 sin6;
207 		struct rtentry *rt;
208 
209 		bzero(&sin6, sizeof(sin6));
210 		sin6.sin6_family = AF_INET6;
211 		sin6.sin6_len = sizeof(struct sockaddr_in6);
212 		sin6.sin6_addr = ip6->ip6_src;
213 		sin6.sin6_scope_id = 0; /* XXX */
214 
215 		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
216 		    sc->gif_fibnum);
217 		if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
218 			if (rt != NULL)
219 				RTFREE_LOCKED(rt);
220 			return (0);
221 		}
222 		RTFREE_LOCKED(rt);
223 	}
224 	return (ret);
225 }
226 
227 int
228 in6_gif_attach(struct gif_softc *sc)
229 {
230 
231 	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
232 	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
233 	    (void *)&in6_gif_protosw, sc);
234 	if (sc->gif_ecookie == NULL)
235 		return (EEXIST);
236 	return (0);
237 }
238