xref: /dragonfly/sys/netinet6/in6_gif.c (revision 1847e88f) 
1 /*	$FreeBSD: src/sys/netinet6/in6_gif.c,v 1.2.2.7 2003/01/23 21:06:47 sam Exp $	*/
2 /*	$DragonFly: src/sys/netinet6/in6_gif.c,v 1.15 2006/01/14 11:44:25 swildner Exp $	*/
3 /*	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $	*/
4 
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/socket.h>
40 #include <sys/sockio.h>
41 #include <sys/mbuf.h>
42 #include <sys/errno.h>
43 #include <sys/queue.h>
44 #include <sys/syslog.h>
45 #include <sys/protosw.h>
46 
47 #include <sys/malloc.h>
48 
49 #include <net/if.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #ifdef INET
55 #include <netinet/ip.h>
56 #endif
57 #include <netinet/ip_encap.h>
58 #ifdef INET6
59 #include <netinet/ip6.h>
60 #include <netinet6/ip6_var.h>
61 #include <netinet6/in6_gif.h>
62 #include <netinet6/in6_var.h>
63 #endif
64 #include <netinet6/ip6protosw.h>
65 #include <netinet/ip_ecn.h>
66 #ifdef INET6
67 #include <netinet6/ip6_ecn.h>
68 #endif
69 
70 #include <net/gif/if_gif.h>
71 
72 #include <net/net_osdep.h>
73 
74 #ifdef INET6
75 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
76 			 struct ifnet *);
77 
78 extern  struct domain inet6domain;
79 struct ip6protosw in6_gif_protosw =
80 { SOCK_RAW,	&inet6domain,	0/*IPPROTO_IPV[46]*/,	PR_ATOMIC|PR_ADDR,
81   in6_gif_input, rip6_output,	0,		rip6_ctloutput,
82   cpu0_soport,
83   0,		0,		0,		0,
84   &rip6_usrreqs
85 };
86 
87 int
88 in6_gif_output(struct ifnet *ifp,
89 	       int family,	/* family of the packet to be encapsulate. */
90 	       struct mbuf *m)
91 {
92 	struct gif_softc *sc = (struct gif_softc*)ifp;
93 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
94 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
95 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
96 	struct ip6_hdr *ip6;
97 	int proto;
98 	u_int8_t itos, otos;
99 
100 	if (sin6_src == NULL || sin6_dst == NULL ||
101 	    sin6_src->sin6_family != AF_INET6 ||
102 	    sin6_dst->sin6_family != AF_INET6) {
103 		m_freem(m);
104 		return EAFNOSUPPORT;
105 	}
106 
107 	switch (family) {
108 #ifdef INET
109 	case AF_INET:
110 	    {
111 		struct ip *ip;
112 
113 		proto = IPPROTO_IPV4;
114 		if (m->m_len < sizeof(*ip)) {
115 			m = m_pullup(m, sizeof(*ip));
116 			if (!m)
117 				return ENOBUFS;
118 		}
119 		ip = mtod(m, struct ip *);
120 		itos = ip->ip_tos;
121 		break;
122 	    }
123 #endif
124 #ifdef INET6
125 	case AF_INET6:
126 	    {
127 		struct ip6_hdr *ip6;
128 		proto = IPPROTO_IPV6;
129 		if (m->m_len < sizeof(*ip6)) {
130 			m = m_pullup(m, sizeof(*ip6));
131 			if (!m)
132 				return ENOBUFS;
133 		}
134 		ip6 = mtod(m, struct ip6_hdr *);
135 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
136 		break;
137 	    }
138 #endif
139 	default:
140 #ifdef DEBUG
141 		printf("in6_gif_output: warning: unknown family %d passed\n",
142 			family);
143 #endif
144 		m_freem(m);
145 		return EAFNOSUPPORT;
146 	}
147 
148 	/* prepend new IP header */
149 	M_PREPEND(m, sizeof(struct ip6_hdr), MB_DONTWAIT);
150 	if (m && m->m_len < sizeof(struct ip6_hdr))
151 		m = m_pullup(m, sizeof(struct ip6_hdr));
152 	if (m == NULL) {
153 		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
154 		return ENOBUFS;
155 	}
156 
157 	ip6 = mtod(m, struct ip6_hdr *);
158 	ip6->ip6_flow	= 0;
159 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
160 	ip6->ip6_vfc	|= IPV6_VERSION;
161 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
162 	ip6->ip6_nxt	= proto;
163 	ip6->ip6_hlim	= ip6_gif_hlim;
164 	ip6->ip6_src	= sin6_src->sin6_addr;
165 	/* bidirectional configured tunnel mode */
166 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
167 		ip6->ip6_dst = sin6_dst->sin6_addr;
168 	else  {
169 		m_freem(m);
170 		return ENETUNREACH;
171 	}
172 	if (ifp->if_flags & IFF_LINK1)
173 		ip_ecn_ingress(ECN_ALLOWED, &otos, &itos);
174 	else
175 		ip_ecn_ingress(ECN_NOCARE, &otos, &itos);
176 	ip6->ip6_flow &= ~ntohl(0xff00000);
177 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
178 
179 	if (dst->sin6_family != sin6_dst->sin6_family ||
180 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
181 		/* cache route doesn't match */
182 		bzero(dst, sizeof(*dst));
183 		dst->sin6_family = sin6_dst->sin6_family;
184 		dst->sin6_len = sizeof(struct sockaddr_in6);
185 		dst->sin6_addr = sin6_dst->sin6_addr;
186 		if (sc->gif_ro6.ro_rt != NULL) {
187 			RTFREE(sc->gif_ro6.ro_rt);
188 			sc->gif_ro6.ro_rt = NULL;
189 		}
190 #if 0
191 		sc->gif_if.if_mtu = GIF_MTU;
192 #endif
193 	}
194 
195 	if (sc->gif_ro6.ro_rt == NULL) {
196 		rtalloc((struct route *)&sc->gif_ro6);
197 		if (sc->gif_ro6.ro_rt == NULL) {
198 			m_freem(m);
199 			return ENETUNREACH;
200 		}
201 
202 		/* if it constitutes infinite encapsulation, punt. */
203 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
204 			m_freem(m);
205 			return ENETUNREACH;	/*XXX*/
206 		}
207 #if 0
208 		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
209 			- sizeof(struct ip6_hdr);
210 #endif
211 	}
212 
213 #ifdef IPV6_MINMTU
214 	/*
215 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
216 	 * it is too painful to ask for resend of inner packet, to achieve
217 	 * path MTU discovery for encapsulated packets.
218 	 */
219 	return(ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL));
220 #else
221 	return(ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL));
222 #endif
223 }
224 
225 int
226 in6_gif_input(struct mbuf **mp, int *offp, int proto)
227 {
228 	struct mbuf *m = *mp;
229 	struct ifnet *gifp = NULL;
230 	struct ip6_hdr *ip6;
231 	int af = 0;
232 	u_int32_t otos;
233 
234 	ip6 = mtod(m, struct ip6_hdr *);
235 
236 	gifp = (struct ifnet *)encap_getarg(m);
237 
238 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
239 		m_freem(m);
240 		ip6stat.ip6s_nogif++;
241 		return IPPROTO_DONE;
242 	}
243 
244 	otos = ip6->ip6_flow;
245 	m_adj(m, *offp);
246 
247 	switch (proto) {
248 #ifdef INET
249 	case IPPROTO_IPV4:
250 	    {
251 		struct ip *ip;
252 		u_int8_t otos8;
253 		af = AF_INET;
254 		otos8 = (ntohl(otos) >> 20) & 0xff;
255 		if (m->m_len < sizeof(*ip)) {
256 			m = m_pullup(m, sizeof(*ip));
257 			if (!m)
258 				return IPPROTO_DONE;
259 		}
260 		ip = mtod(m, struct ip *);
261 		if (gifp->if_flags & IFF_LINK1)
262 			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
263 		else
264 			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
265 		break;
266 	    }
267 #endif /* INET */
268 #ifdef INET6
269 	case IPPROTO_IPV6:
270 	    {
271 		struct ip6_hdr *ip6;
272 		af = AF_INET6;
273 		if (m->m_len < sizeof(*ip6)) {
274 			m = m_pullup(m, sizeof(*ip6));
275 			if (!m)
276 				return IPPROTO_DONE;
277 		}
278 		ip6 = mtod(m, struct ip6_hdr *);
279 		if (gifp->if_flags & IFF_LINK1)
280 			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
281 		else
282 			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
283 		break;
284 	    }
285 #endif
286 	default:
287 		ip6stat.ip6s_nogif++;
288 		m_freem(m);
289 		return IPPROTO_DONE;
290 	}
291 
292 	gif_input(m, af, gifp);
293 	return IPPROTO_DONE;
294 }
295 
296 /*
297  * validate outer address.
298  */
299 static int
300 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
301 	      struct ifnet *ifp)
302 {
303 	struct sockaddr_in6 *src, *dst;
304 
305 	src = (struct sockaddr_in6 *)sc->gif_psrc;
306 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
307 
308 	/*
309 	 * Check for address match.  Note that the check is for an incoming
310 	 * packet.  We should compare the *source* address in our configuration
311 	 * and the *destination* address of the packet, and vice versa.
312 	 */
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 		bzero(&sin6, sizeof(sin6));
325 		sin6.sin6_family = AF_INET6;
326 		sin6.sin6_len = sizeof(struct sockaddr_in6);
327 		sin6.sin6_addr = ip6->ip6_src;
328 		sin6.sin6_scope_id = 0; /* XXX */
329 
330 		rt = rtpurelookup((struct sockaddr *)&sin6);
331 		if (rt != NULL)
332 			--rt->rt_refcnt;
333 		if (rt == NULL || rt->rt_ifp != ifp) {
334 #if 0
335 			log(LOG_WARNING, "%s: packet from %s dropped "
336 			    "due to ingress filter\n", if_name(&sc->gif_if),
337 			    ip6_sprintf(&sin6.sin6_addr));
338 #endif
339 			return 0;
340 		}
341 	}
342 
343 	return 128 * 2;
344 }
345 
346 /*
347  * we know that we are in IFF_UP, outer address available, and outer family
348  * matched the physical addr family.  see gif_encapcheck().
349  * sanity check for arg should have been done in the caller.
350  */
351 int
352 gif_encapcheck6(const 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), (caddr_t)&ip6);
362 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
363 
364 	return gif_validate6(&ip6, sc, ifp);
365 }
366 
367 int
368 in6_gif_attach(struct gif_softc *sc)
369 {
370 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
371 	    (struct protosw *)&in6_gif_protosw, sc);
372 	if (sc->encap_cookie6 == NULL)
373 		return EEXIST;
374 	return 0;
375 }
376 
377 int
378 in6_gif_detach(struct gif_softc *sc)
379 {
380 	int error;
381 
382 	error = encap_detach(sc->encap_cookie6);
383 	if (error == 0)
384 		sc->encap_cookie6 = NULL;
385 	return error;
386 }
387 
388 #endif /* INET6 */
389