xref: /dragonfly/sys/netinet6/in6_gif.c (revision 25a2db75) 
1 /*	$FreeBSD: src/sys/netinet6/in6_gif.c,v 1.2.2.7 2003/01/23 21:06:47 sam Exp $	*/
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/gif/if_gif.h>
70 
71 #include <net/net_osdep.h>
72 
73 #ifdef INET6
74 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
75 			 struct ifnet *);
76 
77 extern  struct domain inet6domain;
78 struct protosw in6_gif_protosw =
79     {
80 	.pr_type = SOCK_RAW,
81 	.pr_domain = &inet6domain,
82 	.pr_protocol = 0/*IPPROTO_IPV[46]*/,
83 	.pr_flags = PR_ATOMIC|PR_ADDR,
84 
85 	.pr_input = in6_gif_input,
86 	.pr_output = rip6_output,
87 	.pr_ctlinput = NULL,
88 	.pr_ctloutput = rip6_ctloutput,
89 
90 	.pr_usrreqs = &rip6_usrreqs
91     };
92 
93 /*
94  * family = family of the packet to be encapsulate.
95  */
96 int
97 in6_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
98 {
99 	struct gif_softc *sc = (struct gif_softc*)ifp;
100 	struct route_in6 *ro = &sc->gif_ro6[mycpu->gd_cpuid];
101 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&ro->ro_dst;
102 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
103 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
104 	struct ip6_hdr *ip6;
105 	int proto;
106 	u_int8_t itos, otos;
107 
108 	if (sin6_src == NULL || sin6_dst == NULL ||
109 	    sin6_src->sin6_family != AF_INET6 ||
110 	    sin6_dst->sin6_family != AF_INET6) {
111 		m_freem(m);
112 		return EAFNOSUPPORT;
113 	}
114 
115 	switch (family) {
116 #ifdef INET
117 	case AF_INET:
118 	    {
119 		struct ip *ip;
120 
121 		proto = IPPROTO_IPV4;
122 		if (m->m_len < sizeof(*ip)) {
123 			m = m_pullup(m, sizeof(*ip));
124 			if (!m)
125 				return ENOBUFS;
126 		}
127 		ip = mtod(m, struct ip *);
128 		itos = ip->ip_tos;
129 		break;
130 	    }
131 #endif
132 #ifdef INET6
133 	case AF_INET6:
134 	    {
135 		struct ip6_hdr *ip6;
136 		proto = IPPROTO_IPV6;
137 		if (m->m_len < sizeof(*ip6)) {
138 			m = m_pullup(m, sizeof(*ip6));
139 			if (!m)
140 				return ENOBUFS;
141 		}
142 		ip6 = mtod(m, struct ip6_hdr *);
143 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
144 		break;
145 	    }
146 #endif
147 	default:
148 #ifdef DEBUG
149 		kprintf("in6_gif_output: warning: unknown family %d passed\n",
150 			family);
151 #endif
152 		m_freem(m);
153 		return EAFNOSUPPORT;
154 	}
155 
156 	/* prepend new IP header */
157 	M_PREPEND(m, sizeof(struct ip6_hdr), MB_DONTWAIT);
158 	if (m && m->m_len < sizeof(struct ip6_hdr))
159 		m = m_pullup(m, sizeof(struct ip6_hdr));
160 	if (m == NULL) {
161 		kprintf("ENOBUFS in in6_gif_output %d\n", __LINE__);
162 		return ENOBUFS;
163 	}
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 (ro->ro_rt != NULL) {
195 			RTFREE(ro->ro_rt);
196 			ro->ro_rt = NULL;
197 		}
198 #if 0
199 		sc->gif_if.if_mtu = GIF_MTU;
200 #endif
201 	}
202 
203 	if (ro->ro_rt == NULL) {
204 		rtalloc((struct route *)ro);
205 		if (ro->ro_rt == NULL) {
206 			m_freem(m);
207 			return ENETUNREACH;
208 		}
209 
210 		/* if it constitutes infinite encapsulation, punt. */
211 		if (ro->ro_rt->rt_ifp == ifp) {
212 			m_freem(m);
213 			return ENETUNREACH;	/*XXX*/
214 		}
215 #if 0
216 		ifp->if_mtu = ro->ro_rt->rt_ifp->if_mtu -
217 			      sizeof(struct ip6_hdr);
218 #endif
219 	}
220 
221 #ifdef IPV6_MINMTU
222 	/*
223 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
224 	 * it is too painful to ask for resend of inner packet, to achieve
225 	 * path MTU discovery for encapsulated packets.
226 	 */
227 	return (ip6_output(m, 0, ro, IPV6_MINMTU, 0, NULL, NULL));
228 #else
229 	return (ip6_output(m, 0, ro, 0, 0, NULL, NULL));
230 #endif
231 }
232 
233 int
234 in6_gif_input(struct mbuf **mp, int *offp, int 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)) {
247 		m_freem(m);
248 		ip6stat.ip6s_nogif++;
249 		return IPPROTO_DONE;
250 	}
251 
252 	otos = ip6->ip6_flow;
253 	m_adj(m, *offp);
254 
255 	switch (proto) {
256 #ifdef INET
257 	case IPPROTO_IPV4:
258 	    {
259 		struct ip *ip;
260 		u_int8_t otos8;
261 		af = AF_INET;
262 		otos8 = (ntohl(otos) >> 20) & 0xff;
263 		if (m->m_len < sizeof(*ip)) {
264 			m = m_pullup(m, sizeof(*ip));
265 			if (!m)
266 				return IPPROTO_DONE;
267 		}
268 		ip = mtod(m, struct ip *);
269 		if (gifp->if_flags & IFF_LINK1)
270 			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
271 		else
272 			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
273 		break;
274 	    }
275 #endif /* INET */
276 #ifdef INET6
277 	case IPPROTO_IPV6:
278 	    {
279 		struct ip6_hdr *ip6;
280 		af = AF_INET6;
281 		if (m->m_len < sizeof(*ip6)) {
282 			m = m_pullup(m, sizeof(*ip6));
283 			if (!m)
284 				return IPPROTO_DONE;
285 		}
286 		ip6 = mtod(m, struct ip6_hdr *);
287 		if (gifp->if_flags & IFF_LINK1)
288 			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
289 		else
290 			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
291 		break;
292 	    }
293 #endif
294 	default:
295 		ip6stat.ip6s_nogif++;
296 		m_freem(m);
297 		return IPPROTO_DONE;
298 	}
299 
300 	gif_input(m, af, gifp);
301 	return IPPROTO_DONE;
302 }
303 
304 /*
305  * validate outer address.
306  */
307 static int
308 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
309 	      struct ifnet *ifp)
310 {
311 	struct sockaddr_in6 *src, *dst;
312 
313 	src = (struct sockaddr_in6 *)sc->gif_psrc;
314 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
315 
316 	/*
317 	 * Check for address match.  Note that the check is for an incoming
318 	 * packet.  We should compare the *source* address in our configuration
319 	 * and the *destination* address of the packet, and vice versa.
320 	 */
321 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
322 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
323 		return 0;
324 
325 	/* martian filters on outer source - done in ip6_input */
326 
327 	/* ingress filters on outer source */
328 	if (!(sc->gif_if.if_flags & IFF_LINK2) && ifp) {
329 		struct sockaddr_in6 sin6;
330 		struct rtentry *rt;
331 
332 		bzero(&sin6, sizeof(sin6));
333 		sin6.sin6_family = AF_INET6;
334 		sin6.sin6_len = sizeof(struct sockaddr_in6);
335 		sin6.sin6_addr = ip6->ip6_src;
336 		sin6.sin6_scope_id = 0; /* XXX */
337 
338 		rt = rtpurelookup((struct sockaddr *)&sin6);
339 		if (rt != NULL)
340 			--rt->rt_refcnt;
341 		if (rt == NULL || rt->rt_ifp != ifp) {
342 #if 0
343 			log(LOG_WARNING, "%s: packet from %s dropped "
344 			    "due to ingress filter\n", if_name(&sc->gif_if),
345 			    ip6_sprintf(&sin6.sin6_addr));
346 #endif
347 			return 0;
348 		}
349 	}
350 
351 	return 128 * 2;
352 }
353 
354 /*
355  * we know that we are in IFF_UP, outer address available, and outer family
356  * matched the physical addr family.  see gif_encapcheck().
357  * sanity check for arg should have been done in the caller.
358  */
359 int
360 gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
361 {
362 	struct ip6_hdr ip6;
363 	struct gif_softc *sc;
364 	struct ifnet *ifp;
365 
366 	/* sanity check done in caller */
367 	sc = (struct gif_softc *)arg;
368 
369 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
370 	ifp = (m->m_flags & M_PKTHDR) ? m->m_pkthdr.rcvif : NULL;
371 
372 	return gif_validate6(&ip6, sc, ifp);
373 }
374 
375 int
376 in6_gif_attach(struct gif_softc *sc)
377 {
378 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
379 	    &in6_gif_protosw, sc);
380 	if (sc->encap_cookie6 == NULL)
381 		return EEXIST;
382 	return 0;
383 }
384 
385 int
386 in6_gif_detach(struct gif_softc *sc)
387 {
388 	int error;
389 
390 	error = encap_detach(sc->encap_cookie6);
391 	if (error == 0)
392 		sc->encap_cookie6 = NULL;
393 	return error;
394 }
395 
396 #endif /* INET6 */
397