xref: /freebsd/sys/netinet6/in6_gif.c (revision 6af83ee0d2941d18880b6aaa2b4facd1d30c6106) 
1 /*	$FreeBSD$	*/
2 /*	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 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 "opt_inet.h"
34 #include "opt_inet6.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/socket.h>
39 #include <sys/sockio.h>
40 #include <sys/mbuf.h>
41 #include <sys/errno.h>
42 #include <sys/queue.h>
43 #include <sys/syslog.h>
44 #include <sys/protosw.h>
45 
46 #include <sys/malloc.h>
47 
48 #include <net/if.h>
49 #include <net/route.h>
50 
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #ifdef INET
54 #include <netinet/ip.h>
55 #endif
56 #include <netinet/ip_encap.h>
57 #ifdef INET6
58 #include <netinet/ip6.h>
59 #include <netinet6/ip6_var.h>
60 #include <netinet6/in6_gif.h>
61 #include <netinet6/in6_var.h>
62 #endif
63 #include <netinet6/ip6protosw.h>
64 #include <netinet/ip_ecn.h>
65 #ifdef INET6
66 #include <netinet6/ip6_ecn.h>
67 #endif
68 
69 #include <net/if_gif.h>
70 
71 #include <net/net_osdep.h>
72 
73 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
74 			 struct ifnet *);
75 
76 extern  struct domain inet6domain;
77 struct ip6protosw in6_gif_protosw =
78 { SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
79   in6_gif_input, rip6_output,	0,		rip6_ctloutput,
80   0,
81   0,		0,		0,		0,
82   &rip6_usrreqs
83 };
84 
85 int
86 in6_gif_output(ifp, family, m)
87 	struct ifnet *ifp;
88 	int family; /* family of the packet to be encapsulate. */
89 	struct mbuf *m;
90 {
91 	struct gif_softc *sc = (struct gif_softc*)ifp;
92 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
93 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
94 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
95 	struct ip6_hdr *ip6;
96 	int proto, error;
97 	u_int8_t itos, otos;
98 
99 	if (sin6_src == NULL || sin6_dst == NULL ||
100 	    sin6_src->sin6_family != AF_INET6 ||
101 	    sin6_dst->sin6_family != AF_INET6) {
102 		m_freem(m);
103 		return EAFNOSUPPORT;
104 	}
105 
106 	switch (family) {
107 #ifdef INET
108 	case AF_INET:
109 	    {
110 		struct ip *ip;
111 
112 		proto = IPPROTO_IPV4;
113 		if (m->m_len < sizeof(*ip)) {
114 			m = m_pullup(m, sizeof(*ip));
115 			if (!m)
116 				return ENOBUFS;
117 		}
118 		ip = mtod(m, struct ip *);
119 		itos = ip->ip_tos;
120 		break;
121 	    }
122 #endif
123 #ifdef INET6
124 	case AF_INET6:
125 	    {
126 		struct ip6_hdr *ip6;
127 		proto = IPPROTO_IPV6;
128 		if (m->m_len < sizeof(*ip6)) {
129 			m = m_pullup(m, sizeof(*ip6));
130 			if (!m)
131 				return ENOBUFS;
132 		}
133 		ip6 = mtod(m, struct ip6_hdr *);
134 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
135 		break;
136 	    }
137 #endif
138 	default:
139 #ifdef DEBUG
140 		printf("in6_gif_output: warning: unknown family %d passed\n",
141 			family);
142 #endif
143 		m_freem(m);
144 		return EAFNOSUPPORT;
145 	}
146 
147 	/* prepend new IP header */
148 	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
149 	if (m && m->m_len < sizeof(struct ip6_hdr))
150 		m = m_pullup(m, sizeof(struct ip6_hdr));
151 	if (m == NULL) {
152 		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
153 		return ENOBUFS;
154 	}
155 
156 	ip6 = mtod(m, struct ip6_hdr *);
157 	ip6->ip6_flow	= 0;
158 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
159 	ip6->ip6_vfc	|= IPV6_VERSION;
160 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
161 	ip6->ip6_nxt	= proto;
162 	ip6->ip6_hlim	= ip6_gif_hlim;
163 	ip6->ip6_src	= sin6_src->sin6_addr;
164 	/* bidirectional configured tunnel mode */
165 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
166 		ip6->ip6_dst = sin6_dst->sin6_addr;
167 	else  {
168 		m_freem(m);
169 		return ENETUNREACH;
170 	}
171 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
172 		       &otos, &itos);
173 	ip6->ip6_flow &= ~htonl(0xff << 20);
174 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
175 
176 	if (dst->sin6_family != sin6_dst->sin6_family ||
177 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
178 		/* cache route doesn't match */
179 		bzero(dst, sizeof(*dst));
180 		dst->sin6_family = sin6_dst->sin6_family;
181 		dst->sin6_len = sizeof(struct sockaddr_in6);
182 		dst->sin6_addr = sin6_dst->sin6_addr;
183 		if (sc->gif_ro6.ro_rt) {
184 			RTFREE(sc->gif_ro6.ro_rt);
185 			sc->gif_ro6.ro_rt = NULL;
186 		}
187 #if 0
188 		sc->gif_if.if_mtu = GIF_MTU;
189 #endif
190 	}
191 
192 	if (sc->gif_ro6.ro_rt == NULL) {
193 		rtalloc((struct route *)&sc->gif_ro6);
194 		if (sc->gif_ro6.ro_rt == NULL) {
195 			m_freem(m);
196 			return ENETUNREACH;
197 		}
198 
199 		/* if it constitutes infinite encapsulation, punt. */
200 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
201 			m_freem(m);
202 			return ENETUNREACH;	/*XXX*/
203 		}
204 #if 0
205 		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
206 			- sizeof(struct ip6_hdr);
207 #endif
208 	}
209 
210 #ifdef IPV6_MINMTU
211 	/*
212 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
213 	 * it is too painful to ask for resend of inner packet, to achieve
214 	 * path MTU discovery for encapsulated packets.
215 	 */
216 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
217 #else
218 	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
219 #endif
220 
221 	if (!(sc->gif_if.if_flags & IFF_LINK0) &&
222 	    sc->gif_ro6.ro_rt != NULL) {
223 		RTFREE(sc->gif_ro6.ro_rt);
224 		sc->gif_ro6.ro_rt = NULL;
225 	}
226 
227 	return (error);
228 }
229 
230 int
231 in6_gif_input(mp, offp, proto)
232 	struct mbuf **mp;
233 	int *offp, proto;
234 {
235 	struct mbuf *m = *mp;
236 	struct ifnet *gifp = NULL;
237 	struct ip6_hdr *ip6;
238 	int af = 0;
239 	u_int32_t otos;
240 
241 	ip6 = mtod(m, struct ip6_hdr *);
242 
243 	gifp = (struct ifnet *)encap_getarg(m);
244 
245 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
246 		m_freem(m);
247 		ip6stat.ip6s_nogif++;
248 		return IPPROTO_DONE;
249 	}
250 
251 	otos = ip6->ip6_flow;
252 	m_adj(m, *offp);
253 
254 	switch (proto) {
255 #ifdef INET
256 	case IPPROTO_IPV4:
257 	    {
258 		struct ip *ip;
259 		u_int8_t otos8;
260 		af = AF_INET;
261 		otos8 = (ntohl(otos) >> 20) & 0xff;
262 		if (m->m_len < sizeof(*ip)) {
263 			m = m_pullup(m, sizeof(*ip));
264 			if (!m)
265 				return IPPROTO_DONE;
266 		}
267 		ip = mtod(m, struct ip *);
268 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
269 				  ECN_ALLOWED : ECN_NOCARE,
270 				  &otos8, &ip->ip_tos) == 0) {
271 			m_freem(m);
272 			return IPPROTO_DONE;
273 		}
274 		break;
275 	    }
276 #endif /* INET */
277 #ifdef INET6
278 	case IPPROTO_IPV6:
279 	    {
280 		struct ip6_hdr *ip6;
281 		af = AF_INET6;
282 		if (m->m_len < sizeof(*ip6)) {
283 			m = m_pullup(m, sizeof(*ip6));
284 			if (!m)
285 				return IPPROTO_DONE;
286 		}
287 		ip6 = mtod(m, struct ip6_hdr *);
288 		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
289 				   ECN_ALLOWED : ECN_NOCARE,
290 				   &otos, &ip6->ip6_flow) == 0) {
291 			m_freem(m);
292 			return IPPROTO_DONE;
293 		}
294 		break;
295 	    }
296 #endif
297 	default:
298 		ip6stat.ip6s_nogif++;
299 		m_freem(m);
300 		return IPPROTO_DONE;
301 	}
302 
303 	gif_input(m, af, gifp);
304 	return IPPROTO_DONE;
305 }
306 
307 /*
308  * validate outer address.
309  */
310 static int
311 gif_validate6(ip6, sc, ifp)
312 	const struct ip6_hdr *ip6;
313 	struct gif_softc *sc;
314 	struct ifnet *ifp;
315 {
316 	struct sockaddr_in6 *src, *dst;
317 
318 	src = (struct sockaddr_in6 *)sc->gif_psrc;
319 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
320 
321 	/*
322 	 * Check for address match.  Note that the check is for an incoming
323 	 * packet.  We should compare the *source* address in our configuration
324 	 * and the *destination* address of the packet, and vice versa.
325 	 */
326 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
327 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
328 		return 0;
329 
330 	/* martian filters on outer source - done in ip6_input */
331 
332 	/* ingress filters on outer source */
333 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
334 		struct sockaddr_in6 sin6;
335 		struct rtentry *rt;
336 
337 		bzero(&sin6, sizeof(sin6));
338 		sin6.sin6_family = AF_INET6;
339 		sin6.sin6_len = sizeof(struct sockaddr_in6);
340 		sin6.sin6_addr = ip6->ip6_src;
341 		sin6.sin6_scope_id = 0; /* XXX */
342 
343 		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
344 		if (!rt || rt->rt_ifp != ifp) {
345 #if 0
346 			log(LOG_WARNING, "%s: packet from %s dropped "
347 			    "due to ingress filter\n", if_name(&sc->gif_if),
348 			    ip6_sprintf(&sin6.sin6_addr));
349 #endif
350 			if (rt)
351 				rtfree(rt);
352 			return 0;
353 		}
354 		rtfree(rt);
355 	}
356 
357 	return 128 * 2;
358 }
359 
360 /*
361  * we know that we are in IFF_UP, outer address available, and outer family
362  * matched the physical addr family.  see gif_encapcheck().
363  * sanity check for arg should have been done in the caller.
364  */
365 int
366 gif_encapcheck6(m, off, proto, arg)
367 	const struct mbuf *m;
368 	int off;
369 	int proto;
370 	void *arg;
371 {
372 	struct ip6_hdr ip6;
373 	struct gif_softc *sc;
374 	struct ifnet *ifp;
375 
376 	/* sanity check done in caller */
377 	sc = (struct gif_softc *)arg;
378 
379 	/* LINTED const cast */
380 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
381 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
382 
383 	return gif_validate6(&ip6, sc, ifp);
384 }
385 
386 int
387 in6_gif_attach(sc)
388 	struct gif_softc *sc;
389 {
390 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
391 	    (struct protosw *)&in6_gif_protosw, sc);
392 	if (sc->encap_cookie6 == NULL)
393 		return EEXIST;
394 	return 0;
395 }
396 
397 int
398 in6_gif_detach(sc)
399 	struct gif_softc *sc;
400 {
401 	int error;
402 
403 	error = encap_detach(sc->encap_cookie6);
404 	if (error == 0)
405 		sc->encap_cookie6 = NULL;
406 	return error;
407 }
408