xref: /netbsd-src/sys/netinet6/in6_gif.c (revision 7fa608457b817eca6e0977b37f758ae064f3c99c) 
1 /*	$NetBSD: in6_gif.c,v 1.52 2007/05/23 17:15:01 christos Exp $	*/
2 /*	$KAME: in6_gif.c,v 1.62 2001/07/29 04:27:25 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: in6_gif.c,v 1.52 2007/05/23 17:15:01 christos Exp $");
35 
36 #include "opt_inet.h"
37 #include "opt_iso.h"
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/socket.h>
42 #include <sys/sockio.h>
43 #include <sys/mbuf.h>
44 #include <sys/errno.h>
45 #include <sys/ioctl.h>
46 #include <sys/queue.h>
47 #include <sys/syslog.h>
48 #include <sys/protosw.h>
49 #include <sys/kernel.h>
50 
51 #include <net/if.h>
52 #include <net/route.h>
53 
54 #include <netinet/in.h>
55 #include <netinet/in_systm.h>
56 #ifdef INET
57 #include <netinet/ip.h>
58 #endif
59 #include <netinet/ip_encap.h>
60 #ifdef INET6
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet6/in6_gif.h>
64 #include <netinet6/in6_var.h>
65 #endif
66 #include <netinet6/ip6protosw.h>
67 #include <netinet/ip_ecn.h>
68 
69 #include <net/if_gif.h>
70 
71 #include <net/net_osdep.h>
72 
73 static int gif_validate6 __P((const struct ip6_hdr *, struct gif_softc *,
74 	struct ifnet *));
75 
76 int	ip6_gif_hlim = GIF_HLIM;
77 
78 extern struct domain inet6domain;
79 const struct ip6protosw in6_gif_protosw =
80 { SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
81   in6_gif_input, rip6_output,	in6_gif_ctlinput, rip6_ctloutput,
82   rip6_usrreq,
83   0,            0,              0,              0,
84 };
85 
86 extern LIST_HEAD(, gif_softc) gif_softc_list;
87 
88 /*
89  * family - family of the packet to be encapsulate.
90  */
91 
92 int
93 in6_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
94 {
95 	struct gif_softc *sc = (struct gif_softc*)ifp;
96 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
97 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
98 	struct ip6_hdr *ip6;
99 	int proto, error;
100 	u_int8_t itos, otos;
101 	union {
102 		struct sockaddr		dst;
103 		struct sockaddr_in6	dst6;
104 	} u;
105 
106 	if (sin6_src == NULL || sin6_dst == NULL ||
107 	    sin6_src->sin6_family != AF_INET6 ||
108 	    sin6_dst->sin6_family != AF_INET6) {
109 		m_freem(m);
110 		return EAFNOSUPPORT;
111 	}
112 
113 	switch (family) {
114 #ifdef INET
115 	case AF_INET:
116 	    {
117 		struct ip *ip;
118 
119 		proto = IPPROTO_IPV4;
120 		if (m->m_len < sizeof(*ip)) {
121 			m = m_pullup(m, sizeof(*ip));
122 			if (!m)
123 				return ENOBUFS;
124 		}
125 		ip = mtod(m, struct ip *);
126 		itos = ip->ip_tos;
127 		break;
128 	    }
129 #endif
130 #ifdef INET6
131 	case AF_INET6:
132 	    {
133 		proto = IPPROTO_IPV6;
134 		if (m->m_len < sizeof(*ip6)) {
135 			m = m_pullup(m, sizeof(*ip6));
136 			if (!m)
137 				return ENOBUFS;
138 		}
139 		ip6 = mtod(m, struct ip6_hdr *);
140 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
141 		break;
142 	    }
143 #endif
144 #ifdef ISO
145 	case AF_ISO:
146 		proto = IPPROTO_EON;
147 		itos = 0;
148 		break;
149 #endif
150 	default:
151 #ifdef DEBUG
152 		printf("in6_gif_output: warning: unknown family %d passed\n",
153 			family);
154 #endif
155 		m_freem(m);
156 		return EAFNOSUPPORT;
157 	}
158 
159 	/* prepend new IP header */
160 	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
161 	if (m && m->m_len < sizeof(struct ip6_hdr))
162 		m = m_pullup(m, sizeof(struct ip6_hdr));
163 	if (m == NULL)
164 		return ENOBUFS;
165 
166 	ip6 = mtod(m, struct ip6_hdr *);
167 	ip6->ip6_flow	= 0;
168 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
169 	ip6->ip6_vfc	|= IPV6_VERSION;
170 #if 0	/* ip6->ip6_plen will be filled by ip6_output */
171 	ip6->ip6_plen	= htons((u_int16_t)m->m_pkthdr.len);
172 #endif
173 	ip6->ip6_nxt	= proto;
174 	ip6->ip6_hlim	= ip6_gif_hlim;
175 	ip6->ip6_src	= sin6_src->sin6_addr;
176 	/* bidirectional configured tunnel mode */
177 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
178 		ip6->ip6_dst = sin6_dst->sin6_addr;
179 	else  {
180 		m_freem(m);
181 		return ENETUNREACH;
182 	}
183 	if (ifp->if_flags & IFF_LINK1)
184 		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
185 	else
186 		ip_ecn_ingress(ECN_NOCARE, &otos, &itos);
187 	ip6->ip6_flow &= ~ntohl(0xff00000);
188 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
189 
190 	sockaddr_in6_init(&u.dst6, &sin6_dst->sin6_addr, 0, 0, 0);
191 	if (rtcache_lookup(&sc->gif_ro, &u.dst) == NULL) {
192 		m_freem(m);
193 		return ENETUNREACH;
194 	}
195 
196 	/* If the route constitutes infinite encapsulation, punt. */
197 	if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
198 		m_freem(m);
199 		return ENETUNREACH;	/* XXX */
200 	}
201 
202 #ifdef IPV6_MINMTU
203 	/*
204 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
205 	 * it is too painful to ask for resend of inner packet, to achieve
206 	 * path MTU discovery for encapsulated packets.
207 	 */
208 	error = ip6_output(m, 0, &sc->gif_ro, IPV6_MINMTU,
209 		    (struct ip6_moptions *)NULL, (struct socket *)NULL, NULL);
210 #else
211 	error = ip6_output(m, 0, &sc->gif_ro, 0,
212 		    (struct ip6_moptions *)NULL, (struct socket *)NULL, NULL);
213 #endif
214 
215 	return (error);
216 }
217 
218 int in6_gif_input(struct mbuf **mp, int *offp, int proto)
219 {
220 	struct mbuf *m = *mp;
221 	struct ifnet *gifp = NULL;
222 	struct ip6_hdr *ip6;
223 	int af = 0;
224 	u_int32_t otos;
225 
226 	ip6 = mtod(m, struct ip6_hdr *);
227 
228 	gifp = (struct ifnet *)encap_getarg(m);
229 
230 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
231 		m_freem(m);
232 		ip6stat.ip6s_nogif++;
233 		return IPPROTO_DONE;
234 	}
235 #ifndef GIF_ENCAPCHECK
236 	if (!gif_validate6(ip6, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
237 		m_freem(m);
238 		ip6stat.ip6s_nogif++;
239 		return IPPROTO_DONE;
240 	}
241 #endif
242 
243 	otos = ip6->ip6_flow;
244 	m_adj(m, *offp);
245 
246 	switch (proto) {
247 #ifdef INET
248 	case IPPROTO_IPV4:
249 	    {
250 		struct ip *ip;
251 		u_int8_t otos8;
252 		af = AF_INET;
253 		otos8 = (ntohl(otos) >> 20) & 0xff;
254 		if (m->m_len < sizeof(*ip)) {
255 			m = m_pullup(m, sizeof(*ip));
256 			if (!m)
257 				return IPPROTO_DONE;
258 		}
259 		ip = mtod(m, struct ip *);
260 		if (gifp->if_flags & IFF_LINK1)
261 			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
262 		else
263 			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
264 		break;
265 	    }
266 #endif /* INET */
267 #ifdef INET6
268 	case IPPROTO_IPV6:
269 	    {
270 		struct ip6_hdr *ip6x;
271 		af = AF_INET6;
272 		if (m->m_len < sizeof(*ip6x)) {
273 			m = m_pullup(m, sizeof(*ip6x));
274 			if (!m)
275 				return IPPROTO_DONE;
276 		}
277 		ip6x = mtod(m, struct ip6_hdr *);
278 		if (gifp->if_flags & IFF_LINK1)
279 			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6x->ip6_flow);
280 		else
281 			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6x->ip6_flow);
282 		break;
283 	    }
284 #endif
285 #ifdef ISO
286 	case IPPROTO_EON:
287 		af = AF_ISO;
288 		break;
289 #endif
290 	default:
291 		ip6stat.ip6s_nogif++;
292 		m_freem(m);
293 		return IPPROTO_DONE;
294 	}
295 
296 	gif_input(m, af, gifp);
297 	return IPPROTO_DONE;
298 }
299 
300 /*
301  * validate outer address.
302  */
303 static int
304 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
305 	struct ifnet *ifp)
306 {
307 	const struct sockaddr_in6 *src, *dst;
308 
309 	src = (struct sockaddr_in6 *)sc->gif_psrc;
310 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
311 
312 	/* check for address match */
313 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
314 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
315 		return 0;
316 
317 	/* martian filters on outer source - done in ip6_input */
318 
319 	/* ingress filters on outer source */
320 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
321 		struct sockaddr_in6 sin6;
322 		struct rtentry *rt;
323 
324 		memset(&sin6, 0, sizeof(sin6));
325 		sin6.sin6_family = AF_INET6;
326 		sin6.sin6_len = sizeof(struct sockaddr_in6);
327 		sin6.sin6_addr = ip6->ip6_src;
328 		/* XXX scopeid */
329 		rt = rtalloc1((struct sockaddr *)&sin6, 0);
330 		if (!rt || rt->rt_ifp != ifp) {
331 #if 0
332 			log(LOG_WARNING, "%s: packet from %s dropped "
333 			    "due to ingress filter\n", if_name(&sc->gif_if),
334 			    ip6_sprintf(&sin6.sin6_addr));
335 #endif
336 			if (rt)
337 				rtfree(rt);
338 			return 0;
339 		}
340 		rtfree(rt);
341 	}
342 
343 	return 128 * 2;
344 }
345 
346 #ifdef GIF_ENCAPCHECK
347 /*
348  * we know that we are in IFF_UP, outer address available, and outer family
349  * matched the physical addr family.  see gif_encapcheck().
350  */
351 int
352 gif_encapcheck6(struct mbuf *m, int off, int proto, void *arg)
353 {
354 	struct ip6_hdr ip6;
355 	struct gif_softc *sc;
356 	struct ifnet *ifp;
357 
358 	/* sanity check done in caller */
359 	sc = (struct gif_softc *)arg;
360 
361 	m_copydata(m, 0, sizeof(ip6), (void *)&ip6);
362 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
363 
364 	return gif_validate6(&ip6, sc, ifp);
365 }
366 #endif
367 
368 int
369 in6_gif_attach(struct gif_softc *sc)
370 {
371 #ifndef GIF_ENCAPCHECK
372 	struct sockaddr_in6 mask6;
373 
374 	bzero(&mask6, sizeof(mask6));
375 	mask6.sin6_len = sizeof(struct sockaddr_in6);
376 	mask6.sin6_addr.s6_addr32[0] = mask6.sin6_addr.s6_addr32[1] =
377 	    mask6.sin6_addr.s6_addr32[2] = mask6.sin6_addr.s6_addr32[3] = ~0;
378 
379 	if (!sc->gif_psrc || !sc->gif_pdst)
380 		return EINVAL;
381 	sc->encap_cookie6 = encap_attach(AF_INET6, -1, sc->gif_psrc,
382 	    (struct sockaddr *)&mask6, sc->gif_pdst, (struct sockaddr *)&mask6,
383 	    (const void *)&in6_gif_protosw, sc);
384 #else
385 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
386 	    (struct protosw *)&in6_gif_protosw, sc);
387 #endif
388 	if (sc->encap_cookie6 == NULL)
389 		return EEXIST;
390 	return 0;
391 }
392 
393 int
394 in6_gif_detach(struct gif_softc *sc)
395 {
396 	int error;
397 
398 	error = encap_detach(sc->encap_cookie6);
399 	if (error == 0)
400 		sc->encap_cookie6 = NULL;
401 
402 	rtcache_free(&sc->gif_ro);
403 
404 	return error;
405 }
406 
407 void
408 in6_gif_ctlinput(int cmd, const struct sockaddr *sa, void *d)
409 {
410 	struct gif_softc *sc;
411 	struct ip6ctlparam *ip6cp = NULL;
412 	struct ip6_hdr *ip6;
413 	const struct sockaddr_in6 *dst6;
414 
415 	if (sa->sa_family != AF_INET6 ||
416 	    sa->sa_len != sizeof(struct sockaddr_in6))
417 		return;
418 
419 	if ((unsigned)cmd >= PRC_NCMDS)
420 		return;
421 	if (cmd == PRC_HOSTDEAD)
422 		d = NULL;
423 	else if (inet6ctlerrmap[cmd] == 0)
424 		return;
425 
426 	/* if the parameter is from icmp6, decode it. */
427 	if (d != NULL) {
428 		ip6cp = (struct ip6ctlparam *)d;
429 		ip6 = ip6cp->ip6c_ip6;
430 	} else {
431 		ip6 = NULL;
432 	}
433 
434 	if (!ip6)
435 		return;
436 
437 	/*
438 	 * for now we don't care which type it was, just flush the route cache.
439 	 * XXX slow.  sc (or sc->encap_cookie6) should be passed from
440 	 * ip_encap.c.
441 	 */
442 	LIST_FOREACH(sc, &gif_softc_list, gif_list) {
443 		if ((sc->gif_if.if_flags & IFF_RUNNING) == 0)
444 			continue;
445 		if (sc->gif_psrc->sa_family != AF_INET6)
446 			continue;
447 		if (sc->gif_ro.ro_rt == NULL)
448 			continue;
449 
450 		dst6 = satocsin6(rtcache_getdst(&sc->gif_ro));
451 		/* XXX scope */
452 		if (dst6 == NULL)
453 			;
454 		else if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst6->sin6_addr))
455 			rtcache_free(&sc->gif_ro);
456 	}
457 }
458