xref: /netbsd/sys/netinet6/in6_gif.c (revision bf9ec67e) 
1 /*	$NetBSD: in6_gif.c,v 1.27 2001/12/21 06:30:44 itojun 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 1.27 2001/12/21 06:30:44 itojun Exp $");
35 
36 #include "opt_inet.h"
37 #include "opt_iso.h"
38 
39 /* define it if you want to use encap_attach_func (it helps *BSD merge) */
40 #define USE_ENCAPCHECK
41 
42 #include <sys/param.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/ioctl.h>
49 #include <sys/queue.h>
50 #include <sys/syslog.h>
51 #include <sys/protosw.h>
52 
53 #include <net/if.h>
54 #include <net/route.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #ifdef INET
59 #include <netinet/ip.h>
60 #endif
61 #include <netinet/ip_encap.h>
62 #ifdef INET6
63 #include <netinet/ip6.h>
64 #include <netinet6/ip6_var.h>
65 #include <netinet6/in6_gif.h>
66 #include <netinet6/in6_var.h>
67 #endif
68 #include <netinet6/ip6protosw.h>
69 #include <netinet/ip_ecn.h>
70 
71 #include <net/if_gif.h>
72 
73 #include <net/net_osdep.h>
74 
75 static int gif_validate6 __P((const struct ip6_hdr *, struct gif_softc *,
76 	struct ifnet *));
77 
78 int	ip6_gif_hlim = GIF_HLIM;
79 
80 extern struct domain inet6domain;
81 struct ip6protosw in6_gif_protosw =
82 { SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
83   in6_gif_input, rip6_output,	in6_gif_ctlinput, rip6_ctloutput,
84   rip6_usrreq,
85   0,            0,              0,              0,
86 };
87 
88 extern LIST_HEAD(, gif_softc) gif_softc_list;
89 
90 int
91 in6_gif_output(ifp, family, m)
92 	struct ifnet *ifp;
93 	int family; /* family of the packet to be encapsulate. */
94 	struct mbuf *m;
95 {
96 	struct gif_softc *sc = (struct gif_softc*)ifp;
97 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
98 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
99 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
100 	struct ip6_hdr *ip6;
101 	int proto, error;
102 	u_int8_t itos, otos;
103 
104 	if (sin6_src == NULL || sin6_dst == NULL ||
105 	    sin6_src->sin6_family != AF_INET6 ||
106 	    sin6_dst->sin6_family != AF_INET6) {
107 		m_freem(m);
108 		return EAFNOSUPPORT;
109 	}
110 
111 	switch (family) {
112 #ifdef INET
113 	case AF_INET:
114 	    {
115 		struct ip *ip;
116 
117 		proto = IPPROTO_IPV4;
118 		if (m->m_len < sizeof(*ip)) {
119 			m = m_pullup(m, sizeof(*ip));
120 			if (!m)
121 				return ENOBUFS;
122 		}
123 		ip = mtod(m, struct ip *);
124 		itos = ip->ip_tos;
125 		break;
126 	    }
127 #endif
128 #ifdef INET6
129 	case AF_INET6:
130 	    {
131 		struct ip6_hdr *ip6;
132 		proto = IPPROTO_IPV6;
133 		if (m->m_len < sizeof(*ip6)) {
134 			m = m_pullup(m, sizeof(*ip6));
135 			if (!m)
136 				return ENOBUFS;
137 		}
138 		ip6 = mtod(m, struct ip6_hdr *);
139 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
140 		break;
141 	    }
142 #endif
143 #ifdef ISO
144 	case AF_ISO:
145 		proto = IPPROTO_EON;
146 		itos = 0;
147 		break;
148 #endif
149 	default:
150 #ifdef DEBUG
151 		printf("in6_gif_output: warning: unknown family %d passed\n",
152 			family);
153 #endif
154 		m_freem(m);
155 		return EAFNOSUPPORT;
156 	}
157 
158 	/* prepend new IP header */
159 	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
160 	if (m && m->m_len < sizeof(struct ip6_hdr))
161 		m = m_pullup(m, sizeof(struct ip6_hdr));
162 	if (m == NULL)
163 		return ENOBUFS;
164 
165 	ip6 = mtod(m, struct ip6_hdr *);
166 	ip6->ip6_flow	= 0;
167 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
168 	ip6->ip6_vfc	|= IPV6_VERSION;
169 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
170 	ip6->ip6_nxt	= proto;
171 	ip6->ip6_hlim	= ip6_gif_hlim;
172 	ip6->ip6_src	= sin6_src->sin6_addr;
173 	/* bidirectional configured tunnel mode */
174 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
175 		ip6->ip6_dst = sin6_dst->sin6_addr;
176 	else  {
177 		m_freem(m);
178 		return ENETUNREACH;
179 	}
180 	if (ifp->if_flags & IFF_LINK1)
181 		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
182 	else
183 		ip_ecn_ingress(ECN_NOCARE, &otos, &itos);
184 	ip6->ip6_flow &= ~ntohl(0xff00000);
185 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
186 
187 	if (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 
214 #ifdef IPV6_MINMTU
215 	/*
216 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
217 	 * it is too painful to ask for resend of inner packet, to achieve
218 	 * path MTU discovery for encapsulated packets.
219 	 */
220 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL);
221 #else
222 	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL);
223 #endif
224 
225 	return(error);
226 }
227 
228 int in6_gif_input(mp, offp, proto)
229 	struct mbuf **mp;
230 	int *offp, proto;
231 {
232 	struct mbuf *m = *mp;
233 	struct ifnet *gifp = NULL;
234 	struct ip6_hdr *ip6;
235 	int af = 0;
236 	u_int32_t otos;
237 
238 	ip6 = mtod(m, struct ip6_hdr *);
239 
240 	gifp = (struct ifnet *)encap_getarg(m);
241 
242 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
243 		m_freem(m);
244 		ip6stat.ip6s_nogif++;
245 		return IPPROTO_DONE;
246 	}
247 #ifndef USE_ENCAPCHECK
248 	if (!gif_validate6(ip6, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
249 		m_freem(m);
250 		ip6stat.ip6s_nogif++;
251 		return IPPROTO_DONE;
252 	}
253 #endif
254 
255 	otos = ip6->ip6_flow;
256 	m_adj(m, *offp);
257 
258 	switch (proto) {
259 #ifdef INET
260 	case IPPROTO_IPV4:
261 	    {
262 		struct ip *ip;
263 		u_int8_t otos8;
264 		af = AF_INET;
265 		otos8 = (ntohl(otos) >> 20) & 0xff;
266 		if (m->m_len < sizeof(*ip)) {
267 			m = m_pullup(m, sizeof(*ip));
268 			if (!m)
269 				return IPPROTO_DONE;
270 		}
271 		ip = mtod(m, struct ip *);
272 		if (gifp->if_flags & IFF_LINK1)
273 			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
274 		else
275 			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
276 		break;
277 	    }
278 #endif /* INET */
279 #ifdef INET6
280 	case IPPROTO_IPV6:
281 	    {
282 		struct ip6_hdr *ip6;
283 		af = AF_INET6;
284 		if (m->m_len < sizeof(*ip6)) {
285 			m = m_pullup(m, sizeof(*ip6));
286 			if (!m)
287 				return IPPROTO_DONE;
288 		}
289 		ip6 = mtod(m, struct ip6_hdr *);
290 		if (gifp->if_flags & IFF_LINK1)
291 			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
292 		else
293 			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
294 		break;
295 	    }
296 #endif
297 #ifdef ISO
298 	case IPPROTO_EON:
299 		af = AF_ISO;
300 		break;
301 #endif
302 	default:
303 		ip6stat.ip6s_nogif++;
304 		m_freem(m);
305 		return IPPROTO_DONE;
306 	}
307 
308 	gif_input(m, af, gifp);
309 	return IPPROTO_DONE;
310 }
311 
312 /*
313  * validate outer address.
314  */
315 static int
316 gif_validate6(ip6, sc, ifp)
317 	const struct ip6_hdr *ip6;
318 	struct gif_softc *sc;
319 	struct ifnet *ifp;
320 {
321 	struct sockaddr_in6 *src, *dst;
322 
323 	src = (struct sockaddr_in6 *)sc->gif_psrc;
324 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
325 
326 	/* check for address match */
327 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
328 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
329 		return 0;
330 
331 	/* martian filters on outer source - done in ip6_input */
332 
333 	/* ingress filters on outer source */
334 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
335 		struct sockaddr_in6 sin6;
336 		struct rtentry *rt;
337 
338 		bzero(&sin6, sizeof(sin6));
339 		sin6.sin6_family = AF_INET6;
340 		sin6.sin6_len = sizeof(struct sockaddr_in6);
341 		sin6.sin6_addr = ip6->ip6_src;
342 		/* XXX scopeid */
343 		rt = rtalloc1((struct sockaddr *)&sin6, 0);
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  */
364 int
365 gif_encapcheck6(m, off, proto, arg)
366 	const struct mbuf *m;
367 	int off;
368 	int proto;
369 	void *arg;
370 {
371 	struct ip6_hdr ip6;
372 	struct gif_softc *sc;
373 	struct ifnet *ifp;
374 
375 	/* sanity check done in caller */
376 	sc = (struct gif_softc *)arg;
377 
378 	/* LINTED const cast */
379 	m_copydata((struct mbuf *)m, 0, sizeof(ip6), (caddr_t)&ip6);
380 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
381 
382 	return gif_validate6(&ip6, sc, ifp);
383 }
384 
385 int
386 in6_gif_attach(sc)
387 	struct gif_softc *sc;
388 {
389 #ifndef USE_ENCAPCHECK
390 	struct sockaddr_in6 mask6;
391 
392 	bzero(&mask6, sizeof(mask6));
393 	mask6.sin6_len = sizeof(struct sockaddr_in6);
394 	mask6.sin6_addr.s6_addr32[0] = mask6.sin6_addr.s6_addr32[1] =
395 	    mask6.sin6_addr.s6_addr32[2] = mask6.sin6_addr.s6_addr32[3] = ~0;
396 
397 	if (!sc->gif_psrc || !sc->gif_pdst)
398 		return EINVAL;
399 	sc->encap_cookie6 = encap_attach(AF_INET6, -1, sc->gif_psrc,
400 	    (struct sockaddr *)&mask6, sc->gif_pdst, (struct sockaddr *)&mask6,
401 	    (struct protosw *)&in6_gif_protosw, sc);
402 #else
403 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
404 	    (struct protosw *)&in6_gif_protosw, sc);
405 #endif
406 	if (sc->encap_cookie6 == NULL)
407 		return EEXIST;
408 	return 0;
409 }
410 
411 int
412 in6_gif_detach(sc)
413 	struct gif_softc *sc;
414 {
415 	int error;
416 
417 	error = encap_detach(sc->encap_cookie6);
418 	if (error == 0)
419 		sc->encap_cookie6 = NULL;
420 	return error;
421 }
422 
423 void
424 in6_gif_ctlinput(cmd, sa, d)
425 	int cmd;
426 	struct sockaddr *sa;
427 	void *d;
428 {
429 	struct gif_softc *sc;
430 	struct ip6ctlparam *ip6cp = NULL;
431 	struct mbuf *m;
432 	struct ip6_hdr *ip6;
433 	int off;
434 	void *cmdarg;
435 	const struct sockaddr_in6 *sa6_src = NULL;
436 	struct sockaddr_in6 *dst6;
437 
438 	if (sa->sa_family != AF_INET6 ||
439 	    sa->sa_len != sizeof(struct sockaddr_in6))
440 		return;
441 
442 	if ((unsigned)cmd >= PRC_NCMDS)
443 		return;
444 	if (cmd == PRC_HOSTDEAD)
445 		d = NULL;
446 	else if (inet6ctlerrmap[cmd] == 0)
447 		return;
448 
449 	/* if the parameter is from icmp6, decode it. */
450 	if (d != NULL) {
451 		ip6cp = (struct ip6ctlparam *)d;
452 		m = ip6cp->ip6c_m;
453 		ip6 = ip6cp->ip6c_ip6;
454 		off = ip6cp->ip6c_off;
455 		cmdarg = ip6cp->ip6c_cmdarg;
456 		sa6_src = ip6cp->ip6c_src;
457 	} else {
458 		m = NULL;
459 		ip6 = NULL;
460 		cmdarg = NULL;
461 		sa6_src = &sa6_any;
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