xref: /netbsd-src/sys/netinet6/in6_gif.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06) 
1 /*	$NetBSD: in6_gif.c,v 1.44 2005/12/11 12:25:02 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 1.44 2005/12/11 12:25:02 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 int
89 in6_gif_output(ifp, family, m)
90 	struct ifnet *ifp;
91 	int family; /* family of the packet to be encapsulate. */
92 	struct mbuf *m;
93 {
94 	struct gif_softc *sc = (struct gif_softc*)ifp;
95 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
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 
102 	if (sin6_src == NULL || sin6_dst == NULL ||
103 	    sin6_src->sin6_family != AF_INET6 ||
104 	    sin6_dst->sin6_family != AF_INET6) {
105 		m_freem(m);
106 		return EAFNOSUPPORT;
107 	}
108 
109 	switch (family) {
110 #ifdef INET
111 	case AF_INET:
112 	    {
113 		struct ip *ip;
114 
115 		proto = IPPROTO_IPV4;
116 		if (m->m_len < sizeof(*ip)) {
117 			m = m_pullup(m, sizeof(*ip));
118 			if (!m)
119 				return ENOBUFS;
120 		}
121 		ip = mtod(m, struct ip *);
122 		itos = ip->ip_tos;
123 		break;
124 	    }
125 #endif
126 #ifdef INET6
127 	case AF_INET6:
128 	    {
129 		proto = IPPROTO_IPV6;
130 		if (m->m_len < sizeof(*ip6)) {
131 			m = m_pullup(m, sizeof(*ip6));
132 			if (!m)
133 				return ENOBUFS;
134 		}
135 		ip6 = mtod(m, struct ip6_hdr *);
136 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
137 		break;
138 	    }
139 #endif
140 #ifdef ISO
141 	case AF_ISO:
142 		proto = IPPROTO_EON;
143 		itos = 0;
144 		break;
145 #endif
146 	default:
147 #ifdef DEBUG
148 		printf("in6_gif_output: warning: unknown family %d passed\n",
149 			family);
150 #endif
151 		m_freem(m);
152 		return EAFNOSUPPORT;
153 	}
154 
155 	/* prepend new IP header */
156 	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
157 	if (m && m->m_len < sizeof(struct ip6_hdr))
158 		m = m_pullup(m, sizeof(struct ip6_hdr));
159 	if (m == NULL)
160 		return ENOBUFS;
161 
162 	ip6 = mtod(m, struct ip6_hdr *);
163 	ip6->ip6_flow	= 0;
164 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
165 	ip6->ip6_vfc	|= IPV6_VERSION;
166 #if 0	/* ip6->ip6_plen will be filled by ip6_output */
167 	ip6->ip6_plen	= htons((u_int16_t)m->m_pkthdr.len);
168 #endif
169 	ip6->ip6_nxt	= proto;
170 	ip6->ip6_hlim	= ip6_gif_hlim;
171 	ip6->ip6_src	= sin6_src->sin6_addr;
172 	/* bidirectional configured tunnel mode */
173 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
174 		ip6->ip6_dst = sin6_dst->sin6_addr;
175 	else  {
176 		m_freem(m);
177 		return ENETUNREACH;
178 	}
179 	if (ifp->if_flags & IFF_LINK1)
180 		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
181 	else
182 		ip_ecn_ingress(ECN_NOCARE, &otos, &itos);
183 	ip6->ip6_flow &= ~ntohl(0xff00000);
184 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
185 
186 	if (sc->gif_route_expire - time.tv_sec <= 0 ||
187 	     dst->sin6_family != sin6_dst->sin6_family ||
188 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
189 		/* cache route doesn't match */
190 		bzero(dst, sizeof(*dst));
191 		dst->sin6_family = sin6_dst->sin6_family;
192 		dst->sin6_len = sizeof(struct sockaddr_in6);
193 		dst->sin6_addr = sin6_dst->sin6_addr;
194 		if (sc->gif_ro6.ro_rt) {
195 			RTFREE(sc->gif_ro6.ro_rt);
196 			sc->gif_ro6.ro_rt = NULL;
197 		}
198 	}
199 
200 	if (sc->gif_ro6.ro_rt == NULL) {
201 		rtalloc((struct route *)&sc->gif_ro6);
202 		if (sc->gif_ro6.ro_rt == NULL) {
203 			m_freem(m);
204 			return ENETUNREACH;
205 		}
206 
207 		/* if it constitutes infinite encapsulation, punt. */
208 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
209 			m_freem(m);
210 			return ENETUNREACH;	/* XXX */
211 		}
212 
213 		sc->gif_route_expire = time.tv_sec + GIF_ROUTE_TTL;
214 	}
215 
216 #ifdef IPV6_MINMTU
217 	/*
218 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
219 	 * it is too painful to ask for resend of inner packet, to achieve
220 	 * path MTU discovery for encapsulated packets.
221 	 */
222 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU,
223 		    (struct ip6_moptions *)NULL, (struct socket *)NULL, NULL);
224 #else
225 	error = ip6_output(m, 0, &sc->gif_ro6, 0,
226 		    (struct ip6_moptions *)NULL, (struct socket *)NULL, NULL);
227 #endif
228 
229 	return (error);
230 }
231 
232 int in6_gif_input(mp, offp, proto)
233 	struct mbuf **mp;
234 	int *offp, proto;
235 {
236 	struct mbuf *m = *mp;
237 	struct ifnet *gifp = NULL;
238 	struct ip6_hdr *ip6;
239 	int af = 0;
240 	u_int32_t otos;
241 
242 	ip6 = mtod(m, struct ip6_hdr *);
243 
244 	gifp = (struct ifnet *)encap_getarg(m);
245 
246 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
247 		m_freem(m);
248 		ip6stat.ip6s_nogif++;
249 		return IPPROTO_DONE;
250 	}
251 #ifndef GIF_ENCAPCHECK
252 	if (!gif_validate6(ip6, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
253 		m_freem(m);
254 		ip6stat.ip6s_nogif++;
255 		return IPPROTO_DONE;
256 	}
257 #endif
258 
259 	otos = ip6->ip6_flow;
260 	m_adj(m, *offp);
261 
262 	switch (proto) {
263 #ifdef INET
264 	case IPPROTO_IPV4:
265 	    {
266 		struct ip *ip;
267 		u_int8_t otos8;
268 		af = AF_INET;
269 		otos8 = (ntohl(otos) >> 20) & 0xff;
270 		if (m->m_len < sizeof(*ip)) {
271 			m = m_pullup(m, sizeof(*ip));
272 			if (!m)
273 				return IPPROTO_DONE;
274 		}
275 		ip = mtod(m, struct ip *);
276 		if (gifp->if_flags & IFF_LINK1)
277 			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
278 		else
279 			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
280 		break;
281 	    }
282 #endif /* INET */
283 #ifdef INET6
284 	case IPPROTO_IPV6:
285 	    {
286 		struct ip6_hdr *ip6x;
287 		af = AF_INET6;
288 		if (m->m_len < sizeof(*ip6x)) {
289 			m = m_pullup(m, sizeof(*ip6x));
290 			if (!m)
291 				return IPPROTO_DONE;
292 		}
293 		ip6x = mtod(m, struct ip6_hdr *);
294 		if (gifp->if_flags & IFF_LINK1)
295 			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6x->ip6_flow);
296 		else
297 			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6x->ip6_flow);
298 		break;
299 	    }
300 #endif
301 #ifdef ISO
302 	case IPPROTO_EON:
303 		af = AF_ISO;
304 		break;
305 #endif
306 	default:
307 		ip6stat.ip6s_nogif++;
308 		m_freem(m);
309 		return IPPROTO_DONE;
310 	}
311 
312 	gif_input(m, af, gifp);
313 	return IPPROTO_DONE;
314 }
315 
316 /*
317  * validate outer address.
318  */
319 static int
320 gif_validate6(ip6, sc, ifp)
321 	const struct ip6_hdr *ip6;
322 	struct gif_softc *sc;
323 	struct ifnet *ifp;
324 {
325 	struct sockaddr_in6 *src, *dst;
326 
327 	src = (struct sockaddr_in6 *)sc->gif_psrc;
328 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
329 
330 	/* check for address match */
331 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
332 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
333 		return 0;
334 
335 	/* martian filters on outer source - done in ip6_input */
336 
337 	/* ingress filters on outer source */
338 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
339 		struct sockaddr_in6 sin6;
340 		struct rtentry *rt;
341 
342 		bzero(&sin6, sizeof(sin6));
343 		sin6.sin6_family = AF_INET6;
344 		sin6.sin6_len = sizeof(struct sockaddr_in6);
345 		sin6.sin6_addr = ip6->ip6_src;
346 		/* XXX scopeid */
347 		rt = rtalloc1((struct sockaddr *)&sin6, 0);
348 		if (!rt || rt->rt_ifp != ifp) {
349 #if 0
350 			log(LOG_WARNING, "%s: packet from %s dropped "
351 			    "due to ingress filter\n", if_name(&sc->gif_if),
352 			    ip6_sprintf(&sin6.sin6_addr));
353 #endif
354 			if (rt)
355 				rtfree(rt);
356 			return 0;
357 		}
358 		rtfree(rt);
359 	}
360 
361 	return 128 * 2;
362 }
363 
364 #ifdef GIF_ENCAPCHECK
365 /*
366  * we know that we are in IFF_UP, outer address available, and outer family
367  * matched the physical addr family.  see gif_encapcheck().
368  */
369 int
370 gif_encapcheck6(m, off, proto, arg)
371 	struct mbuf *m;
372 	int off;
373 	int proto;
374 	void *arg;
375 {
376 	struct ip6_hdr ip6;
377 	struct gif_softc *sc;
378 	struct ifnet *ifp;
379 
380 	/* sanity check done in caller */
381 	sc = (struct gif_softc *)arg;
382 
383 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
384 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
385 
386 	return gif_validate6(&ip6, sc, ifp);
387 }
388 #endif
389 
390 int
391 in6_gif_attach(sc)
392 	struct gif_softc *sc;
393 {
394 #ifndef GIF_ENCAPCHECK
395 	struct sockaddr_in6 mask6;
396 
397 	bzero(&mask6, sizeof(mask6));
398 	mask6.sin6_len = sizeof(struct sockaddr_in6);
399 	mask6.sin6_addr.s6_addr32[0] = mask6.sin6_addr.s6_addr32[1] =
400 	    mask6.sin6_addr.s6_addr32[2] = mask6.sin6_addr.s6_addr32[3] = ~0;
401 
402 	if (!sc->gif_psrc || !sc->gif_pdst)
403 		return EINVAL;
404 	sc->encap_cookie6 = encap_attach(AF_INET6, -1, sc->gif_psrc,
405 	    (struct sockaddr *)&mask6, sc->gif_pdst, (struct sockaddr *)&mask6,
406 	    (const void *)&in6_gif_protosw, sc);
407 #else
408 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
409 	    (struct protosw *)&in6_gif_protosw, sc);
410 #endif
411 	if (sc->encap_cookie6 == NULL)
412 		return EEXIST;
413 	return 0;
414 }
415 
416 int
417 in6_gif_detach(sc)
418 	struct gif_softc *sc;
419 {
420 	int error;
421 
422 	error = encap_detach(sc->encap_cookie6);
423 	if (error == 0)
424 		sc->encap_cookie6 = NULL;
425 
426 	if (sc->gif_ro6.ro_rt) {
427 		RTFREE(sc->gif_ro6.ro_rt);
428 		sc->gif_ro6.ro_rt = NULL;
429 	}
430 
431 	return error;
432 }
433 
434 void
435 in6_gif_ctlinput(cmd, sa, d)
436 	int cmd;
437 	struct sockaddr *sa;
438 	void *d;
439 {
440 	struct gif_softc *sc;
441 	struct ip6ctlparam *ip6cp = NULL;
442 	struct ip6_hdr *ip6;
443 	struct sockaddr_in6 *dst6;
444 
445 	if (sa->sa_family != AF_INET6 ||
446 	    sa->sa_len != sizeof(struct sockaddr_in6))
447 		return;
448 
449 	if ((unsigned)cmd >= PRC_NCMDS)
450 		return;
451 	if (cmd == PRC_HOSTDEAD)
452 		d = NULL;
453 	else if (inet6ctlerrmap[cmd] == 0)
454 		return;
455 
456 	/* if the parameter is from icmp6, decode it. */
457 	if (d != NULL) {
458 		ip6cp = (struct ip6ctlparam *)d;
459 		ip6 = ip6cp->ip6c_ip6;
460 	} else {
461 		ip6 = NULL;
462 	}
463 
464 	if (!ip6)
465 		return;
466 
467 	/*
468 	 * for now we don't care which type it was, just flush the route cache.
469 	 * XXX slow.  sc (or sc->encap_cookie6) should be passed from
470 	 * ip_encap.c.
471 	 */
472 	for (sc = LIST_FIRST(&gif_softc_list); sc;
473 	     sc = LIST_NEXT(sc, gif_list)) {
474 		if ((sc->gif_if.if_flags & IFF_RUNNING) == 0)
475 			continue;
476 		if (sc->gif_psrc->sa_family != AF_INET6)
477 			continue;
478 		if (!sc->gif_ro6.ro_rt)
479 			continue;
480 
481 		dst6 = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
482 		/* XXX scope */
483 		if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &dst6->sin6_addr)) {
484 			/* flush route cache */
485 			RTFREE(sc->gif_ro6.ro_rt);
486 			sc->gif_ro6.ro_rt = NULL;
487 		}
488 	}
489 }
490