xref: /freebsd/sys/netinet6/in6_gif.c (revision 8a4217aacf57330755501a349d0ea662d4880386)
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: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun 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/lock.h>
42 #include <sys/rmlock.h>
43 #include <sys/systm.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/mbuf.h>
47 #include <sys/errno.h>
48 #include <sys/kernel.h>
49 #include <sys/queue.h>
50 #include <sys/syslog.h>
51 #include <sys/sysctl.h>
52 #include <sys/protosw.h>
53 #include <sys/malloc.h>
54 
55 #include <net/if.h>
56 #include <net/if_var.h>
57 #include <net/route.h>
58 #include <net/vnet.h>
59 
60 #include <netinet/in.h>
61 #include <netinet/in_systm.h>
62 #ifdef INET
63 #include <netinet/ip.h>
64 #endif
65 #include <netinet/ip_encap.h>
66 #ifdef INET6
67 #include <netinet/ip6.h>
68 #include <netinet6/ip6_var.h>
69 #include <netinet6/in6_var.h>
70 #endif
71 #include <netinet/ip_ecn.h>
72 #ifdef INET6
73 #include <netinet6/ip6_ecn.h>
74 #include <netinet6/in6_fib.h>
75 #endif
76 
77 #include <net/if_gif.h>
78 
79 #define GIF_HLIM	30
80 static VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
81 #define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
82 
83 SYSCTL_DECL(_net_inet6_ip6);
84 SYSCTL_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_VNET | CTLFLAG_RW,
85     &VNET_NAME(ip6_gif_hlim), 0, "");
86 
87 static int in6_gif_input(struct mbuf **, int *, int);
88 
89 extern  struct domain inet6domain;
90 static struct protosw in6_gif_protosw = {
91 	.pr_type =	SOCK_RAW,
92 	.pr_domain =	&inet6domain,
93 	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
94 	.pr_flags =	PR_ATOMIC|PR_ADDR,
95 	.pr_input =	in6_gif_input,
96 	.pr_output =	rip6_output,
97 	.pr_ctloutput =	rip6_ctloutput,
98 	.pr_usrreqs =	&rip6_usrreqs
99 };
100 
101 int
102 in6_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
103 {
104 	GIF_RLOCK_TRACKER;
105 	struct gif_softc *sc = ifp->if_softc;
106 	struct ip6_hdr *ip6;
107 	int len;
108 
109 	/* prepend new IP header */
110 	len = sizeof(struct ip6_hdr);
111 #ifndef __NO_STRICT_ALIGNMENT
112 	if (proto == IPPROTO_ETHERIP)
113 		len += ETHERIP_ALIGN;
114 #endif
115 	M_PREPEND(m, len, M_NOWAIT);
116 	if (m == NULL)
117 		return (ENOBUFS);
118 #ifndef __NO_STRICT_ALIGNMENT
119 	if (proto == IPPROTO_ETHERIP) {
120 		len = mtod(m, vm_offset_t) & 3;
121 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
122 		    ("in6_gif_output: unexpected misalignment"));
123 		m->m_data += len;
124 		m->m_len -= ETHERIP_ALIGN;
125 	}
126 #endif
127 
128 	ip6 = mtod(m, struct ip6_hdr *);
129 	GIF_RLOCK(sc);
130 	if (sc->gif_family != AF_INET6) {
131 		m_freem(m);
132 		GIF_RUNLOCK(sc);
133 		return (ENETDOWN);
134 	}
135 	bcopy(sc->gif_ip6hdr, ip6, sizeof(struct ip6_hdr));
136 	GIF_RUNLOCK(sc);
137 
138 	ip6->ip6_flow  |= htonl((uint32_t)ecn << 20);
139 	ip6->ip6_nxt	= proto;
140 	ip6->ip6_hlim	= V_ip6_gif_hlim;
141 	/*
142 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
143 	 * it is too painful to ask for resend of inner packet, to achieve
144 	 * path MTU discovery for encapsulated packets.
145 	 */
146 	return (ip6_output(m, 0, NULL, IPV6_MINMTU, 0, NULL, NULL));
147 }
148 
149 static int
150 in6_gif_input(struct mbuf **mp, int *offp, int proto)
151 {
152 	struct mbuf *m = *mp;
153 	struct ifnet *gifp;
154 	struct gif_softc *sc;
155 	struct ip6_hdr *ip6;
156 	uint8_t ecn;
157 
158 	sc = encap_getarg(m);
159 	if (sc == NULL) {
160 		m_freem(m);
161 		IP6STAT_INC(ip6s_nogif);
162 		return (IPPROTO_DONE);
163 	}
164 	gifp = GIF2IFP(sc);
165 	if ((gifp->if_flags & IFF_UP) != 0) {
166 		ip6 = mtod(m, struct ip6_hdr *);
167 		ecn = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
168 		m_adj(m, *offp);
169 		gif_input(m, gifp, proto, ecn);
170 	} else {
171 		m_freem(m);
172 		IP6STAT_INC(ip6s_nogif);
173 	}
174 	return (IPPROTO_DONE);
175 }
176 
177 /*
178  * we know that we are in IFF_UP, outer address available, and outer family
179  * matched the physical addr family.  see gif_encapcheck().
180  */
181 int
182 in6_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
183 {
184 	const struct ip6_hdr *ip6;
185 	struct gif_softc *sc;
186 	int ret;
187 
188 	/* sanity check done in caller */
189 	sc = (struct gif_softc *)arg;
190 	GIF_RLOCK_ASSERT(sc);
191 
192 	/*
193 	 * Check for address match.  Note that the check is for an incoming
194 	 * packet.  We should compare the *source* address in our configuration
195 	 * and the *destination* address of the packet, and vice versa.
196 	 */
197 	ip6 = mtod(m, const struct ip6_hdr *);
198 	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_src, &ip6->ip6_dst))
199 		return (0);
200 	ret = 128;
201 	if (!IN6_ARE_ADDR_EQUAL(&sc->gif_ip6hdr->ip6_dst, &ip6->ip6_src)) {
202 		if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0)
203 			return (0);
204 	} else
205 		ret += 128;
206 
207 	/* ingress filters on outer source */
208 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
209 		struct nhop6_basic nh6;
210 
211 		/* XXX empty scope id */
212 		if (fib6_lookup_nh_basic(sc->gif_fibnum, &ip6->ip6_src, 0, 0, 0,
213 		    &nh6) != 0)
214 			return (0);
215 
216 		if (nh6.nh_ifp != m->m_pkthdr.rcvif)
217 			return (0);
218 	}
219 	return (ret);
220 }
221 
222 int
223 in6_gif_attach(struct gif_softc *sc)
224 {
225 
226 	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
227 	sc->gif_ecookie = encap_attach_func(AF_INET6, -1, gif_encapcheck,
228 	    (void *)&in6_gif_protosw, sc);
229 	if (sc->gif_ecookie == NULL)
230 		return (EEXIST);
231 	return (0);
232 }
233