xref: /freebsd/sys/netinet/in_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: in_gif.c,v 1.54 2001/05/14 14:02:16 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/sysctl.h>
48 #include <sys/protosw.h>
49 #include <sys/malloc.h>
50 
51 #include <net/if.h>
52 #include <net/if_var.h>
53 #include <net/route.h>
54 #include <net/vnet.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #include <netinet/ip.h>
59 #include <netinet/ip_var.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip_encap.h>
62 #include <netinet/ip_ecn.h>
63 
64 #ifdef INET6
65 #include <netinet/ip6.h>
66 #endif
67 
68 #include <net/if_gif.h>
69 
70 static int in_gif_input(struct mbuf **, int *, int);
71 
72 extern  struct domain inetdomain;
73 static struct protosw in_gif_protosw = {
74 	.pr_type =		SOCK_RAW,
75 	.pr_domain =		&inetdomain,
76 	.pr_protocol =		0/* IPPROTO_IPV[46] */,
77 	.pr_flags =		PR_ATOMIC|PR_ADDR,
78 	.pr_input =		in_gif_input,
79 	.pr_output =		rip_output,
80 	.pr_ctloutput =		rip_ctloutput,
81 	.pr_usrreqs =		&rip_usrreqs
82 };
83 
84 #define GIF_TTL		30
85 static VNET_DEFINE(int, ip_gif_ttl) = GIF_TTL;
86 #define	V_ip_gif_ttl		VNET(ip_gif_ttl)
87 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_VNET | CTLFLAG_RW,
88 	&VNET_NAME(ip_gif_ttl), 0, "");
89 
90 int
91 in_gif_output(struct ifnet *ifp, struct mbuf *m, int proto, uint8_t ecn)
92 {
93 	GIF_RLOCK_TRACKER;
94 	struct gif_softc *sc = ifp->if_softc;
95 	struct ip *ip;
96 	int len;
97 
98 	/* prepend new IP header */
99 	len = sizeof(struct ip);
100 #ifndef __NO_STRICT_ALIGNMENT
101 	if (proto == IPPROTO_ETHERIP)
102 		len += ETHERIP_ALIGN;
103 #endif
104 	M_PREPEND(m, len, M_NOWAIT);
105 	if (m == NULL)
106 		return (ENOBUFS);
107 #ifndef __NO_STRICT_ALIGNMENT
108 	if (proto == IPPROTO_ETHERIP) {
109 		len = mtod(m, vm_offset_t) & 3;
110 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
111 		    ("in_gif_output: unexpected misalignment"));
112 		m->m_data += len;
113 		m->m_len -= ETHERIP_ALIGN;
114 	}
115 #endif
116 	ip = mtod(m, struct ip *);
117 	GIF_RLOCK(sc);
118 	if (sc->gif_family != AF_INET) {
119 		m_freem(m);
120 		GIF_RUNLOCK(sc);
121 		return (ENETDOWN);
122 	}
123 	bcopy(sc->gif_iphdr, ip, sizeof(struct ip));
124 	GIF_RUNLOCK(sc);
125 
126 	ip->ip_p = proto;
127 	/* version will be set in ip_output() */
128 	ip->ip_ttl = V_ip_gif_ttl;
129 	ip->ip_len = htons(m->m_pkthdr.len);
130 	ip->ip_tos = ecn;
131 
132 	return (ip_output(m, NULL, NULL, 0, NULL, NULL));
133 }
134 
135 static int
136 in_gif_input(struct mbuf **mp, int *offp, int proto)
137 {
138 	struct mbuf *m = *mp;
139 	struct gif_softc *sc;
140 	struct ifnet *gifp;
141 	struct ip *ip;
142 	uint8_t ecn;
143 
144 	sc = encap_getarg(m);
145 	if (sc == NULL) {
146 		m_freem(m);
147 		KMOD_IPSTAT_INC(ips_nogif);
148 		return (IPPROTO_DONE);
149 	}
150 	gifp = GIF2IFP(sc);
151 	if ((gifp->if_flags & IFF_UP) != 0) {
152 		ip = mtod(m, struct ip *);
153 		ecn = ip->ip_tos;
154 		m_adj(m, *offp);
155 		gif_input(m, gifp, proto, ecn);
156 	} else {
157 		m_freem(m);
158 		KMOD_IPSTAT_INC(ips_nogif);
159 	}
160 	return (IPPROTO_DONE);
161 }
162 
163 /*
164  * we know that we are in IFF_UP, outer address available, and outer family
165  * matched the physical addr family.  see gif_encapcheck().
166  */
167 int
168 in_gif_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
169 {
170 	const struct ip *ip;
171 	struct gif_softc *sc;
172 	int ret;
173 
174 	/* sanity check done in caller */
175 	sc = (struct gif_softc *)arg;
176 	GIF_RLOCK_ASSERT(sc);
177 
178 	/* check for address match */
179 	ip = mtod(m, const struct ip *);
180 	if (sc->gif_iphdr->ip_src.s_addr != ip->ip_dst.s_addr)
181 		return (0);
182 	ret = 32;
183 	if (sc->gif_iphdr->ip_dst.s_addr != ip->ip_src.s_addr) {
184 		if ((sc->gif_options & GIF_IGNORE_SOURCE) == 0)
185 			return (0);
186 	} else
187 		ret += 32;
188 
189 	/* ingress filters on outer source */
190 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0) {
191 		struct sockaddr_in sin;
192 		struct rtentry *rt;
193 
194 		bzero(&sin, sizeof(sin));
195 		sin.sin_family = AF_INET;
196 		sin.sin_len = sizeof(struct sockaddr_in);
197 		sin.sin_addr = ip->ip_src;
198 		/* XXX MRT  check for the interface we would use on output */
199 		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
200 		    0UL, sc->gif_fibnum);
201 		if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
202 			if (rt != NULL)
203 				RTFREE_LOCKED(rt);
204 			return (0);
205 		}
206 		RTFREE_LOCKED(rt);
207 	}
208 	return (ret);
209 }
210 
211 int
212 in_gif_attach(struct gif_softc *sc)
213 {
214 
215 	KASSERT(sc->gif_ecookie == NULL, ("gif_ecookie isn't NULL"));
216 	sc->gif_ecookie = encap_attach_func(AF_INET, -1, gif_encapcheck,
217 	    &in_gif_protosw, sc);
218 	if (sc->gif_ecookie == NULL)
219 		return (EEXIST);
220 	return (0);
221 }
222