xref: /freebsd/sys/netinet6/in6_gif.c (revision 830940567b49bb0c08dfaed40418999e76616909) 
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/mbuf.h>
43 #include <sys/errno.h>
44 #include <sys/queue.h>
45 #include <sys/syslog.h>
46 #include <sys/protosw.h>
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/if_gif.h>
71 
72 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
73 			 struct ifnet *);
74 
75 extern  struct domain inet6domain;
76 struct ip6protosw in6_gif_protosw = {
77 	.pr_type =	SOCK_RAW,
78 	.pr_domain =	&inet6domain,
79 	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
80 	.pr_flags =	PR_ATOMIC|PR_ADDR,
81 	.pr_input =	in6_gif_input,
82 	.pr_output =	rip6_output,
83 	.pr_ctloutput =	rip6_ctloutput,
84 	.pr_usrreqs =	&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 = ifp->if_softc;
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 	struct etherip_header eiphdr;
98 	int error, len, proto;
99 	u_int8_t itos, otos;
100 
101 	GIF_LOCK_ASSERT(sc);
102 
103 	if (sin6_src == NULL || sin6_dst == NULL ||
104 	    sin6_src->sin6_family != AF_INET6 ||
105 	    sin6_dst->sin6_family != AF_INET6) {
106 		m_freem(m);
107 		return EAFNOSUPPORT;
108 	}
109 
110 	switch (family) {
111 #ifdef INET
112 	case AF_INET:
113 	    {
114 		struct ip *ip;
115 
116 		proto = IPPROTO_IPV4;
117 		if (m->m_len < sizeof(*ip)) {
118 			m = m_pullup(m, sizeof(*ip));
119 			if (!m)
120 				return ENOBUFS;
121 		}
122 		ip = mtod(m, struct ip *);
123 		itos = ip->ip_tos;
124 		break;
125 	    }
126 #endif
127 #ifdef INET6
128 	case AF_INET6:
129 	    {
130 		struct ip6_hdr *ip6;
131 		proto = IPPROTO_IPV6;
132 		if (m->m_len < sizeof(*ip6)) {
133 			m = m_pullup(m, sizeof(*ip6));
134 			if (!m)
135 				return ENOBUFS;
136 		}
137 		ip6 = mtod(m, struct ip6_hdr *);
138 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139 		break;
140 	    }
141 #endif
142 	case AF_LINK:
143 		proto = IPPROTO_ETHERIP;
144 
145 		/*
146 		 * GIF_SEND_REVETHIP (disabled by default) intentionally
147 		 * sends an EtherIP packet with revered version field in
148 		 * the header.  This is a knob for backward compatibility
149 		 * with FreeBSD 7.2R or prior.
150 		 */
151 		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
152 			eiphdr.eip_ver = 0;
153 			eiphdr.eip_resvl = ETHERIP_VERSION;
154 			eiphdr.eip_resvh = 0;
155 		} else {
156 			eiphdr.eip_ver = ETHERIP_VERSION;
157 			eiphdr.eip_resvl = 0;
158 			eiphdr.eip_resvh = 0;
159 		}
160 		/* prepend Ethernet-in-IP header */
161 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
162 		if (m && m->m_len < sizeof(struct etherip_header))
163 			m = m_pullup(m, sizeof(struct etherip_header));
164 		if (m == NULL)
165 			return ENOBUFS;
166 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
167 		    sizeof(struct etherip_header));
168 		break;
169 
170 	default:
171 #ifdef DEBUG
172 		printf("in6_gif_output: warning: unknown family %d passed\n",
173 			family);
174 #endif
175 		m_freem(m);
176 		return EAFNOSUPPORT;
177 	}
178 
179 	/* prepend new IP header */
180 	len = sizeof(struct ip6_hdr);
181 #ifndef __NO_STRICT_ALIGNMENT
182 	if (family == AF_LINK)
183 		len += ETHERIP_ALIGN;
184 #endif
185 	M_PREPEND(m, len, M_DONTWAIT);
186 	if (m != NULL && m->m_len < len)
187 		m = m_pullup(m, len);
188 	if (m == NULL) {
189 		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
190 		return ENOBUFS;
191 	}
192 #ifndef __NO_STRICT_ALIGNMENT
193 	if (family == AF_LINK) {
194 		len = mtod(m, vm_offset_t) & 3;
195 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
196 		    ("in6_gif_output: unexpected misalignment"));
197 		m->m_data += len;
198 		m->m_len -= ETHERIP_ALIGN;
199 	}
200 #endif
201 
202 	ip6 = mtod(m, struct ip6_hdr *);
203 	ip6->ip6_flow	= 0;
204 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
205 	ip6->ip6_vfc	|= IPV6_VERSION;
206 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
207 	ip6->ip6_nxt	= proto;
208 	ip6->ip6_hlim	= V_ip6_gif_hlim;
209 	ip6->ip6_src	= sin6_src->sin6_addr;
210 	/* bidirectional configured tunnel mode */
211 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
212 		ip6->ip6_dst = sin6_dst->sin6_addr;
213 	else  {
214 		m_freem(m);
215 		return ENETUNREACH;
216 	}
217 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
218 		       &otos, &itos);
219 	ip6->ip6_flow &= ~htonl(0xff << 20);
220 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
221 
222 	if (dst->sin6_family != sin6_dst->sin6_family ||
223 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
224 		/* cache route doesn't match */
225 		bzero(dst, sizeof(*dst));
226 		dst->sin6_family = sin6_dst->sin6_family;
227 		dst->sin6_len = sizeof(struct sockaddr_in6);
228 		dst->sin6_addr = sin6_dst->sin6_addr;
229 		if (sc->gif_ro6.ro_rt) {
230 			RTFREE(sc->gif_ro6.ro_rt);
231 			sc->gif_ro6.ro_rt = NULL;
232 		}
233 #if 0
234 		GIF2IFP(sc)->if_mtu = GIF_MTU;
235 #endif
236 	}
237 
238 	if (sc->gif_ro6.ro_rt == NULL) {
239 		rtalloc((struct route *)&sc->gif_ro6);
240 		if (sc->gif_ro6.ro_rt == NULL) {
241 			m_freem(m);
242 			return ENETUNREACH;
243 		}
244 
245 		/* if it constitutes infinite encapsulation, punt. */
246 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
247 			m_freem(m);
248 			return ENETUNREACH;	/*XXX*/
249 		}
250 #if 0
251 		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
252 			- sizeof(struct ip6_hdr);
253 #endif
254 	}
255 
256 #ifdef IPV6_MINMTU
257 	/*
258 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
259 	 * it is too painful to ask for resend of inner packet, to achieve
260 	 * path MTU discovery for encapsulated packets.
261 	 */
262 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
263 #else
264 	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
265 #endif
266 
267 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
268 	    sc->gif_ro6.ro_rt != NULL) {
269 		RTFREE(sc->gif_ro6.ro_rt);
270 		sc->gif_ro6.ro_rt = NULL;
271 	}
272 
273 	return (error);
274 }
275 
276 int
277 in6_gif_input(struct mbuf **mp, int *offp, int proto)
278 {
279 	struct mbuf *m = *mp;
280 	struct ifnet *gifp = NULL;
281 	struct gif_softc *sc;
282 	struct ip6_hdr *ip6;
283 	int af = 0;
284 	u_int32_t otos;
285 
286 	ip6 = mtod(m, struct ip6_hdr *);
287 
288 	sc = (struct gif_softc *)encap_getarg(m);
289 	if (sc == NULL) {
290 		m_freem(m);
291 		V_ip6stat.ip6s_nogif++;
292 		return IPPROTO_DONE;
293 	}
294 
295 	gifp = GIF2IFP(sc);
296 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
297 		m_freem(m);
298 		V_ip6stat.ip6s_nogif++;
299 		return IPPROTO_DONE;
300 	}
301 
302 	otos = ip6->ip6_flow;
303 	m_adj(m, *offp);
304 
305 	switch (proto) {
306 #ifdef INET
307 	case IPPROTO_IPV4:
308 	    {
309 		struct ip *ip;
310 		u_int8_t otos8;
311 		af = AF_INET;
312 		otos8 = (ntohl(otos) >> 20) & 0xff;
313 		if (m->m_len < sizeof(*ip)) {
314 			m = m_pullup(m, sizeof(*ip));
315 			if (!m)
316 				return IPPROTO_DONE;
317 		}
318 		ip = mtod(m, struct ip *);
319 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
320 				  ECN_ALLOWED : ECN_NOCARE,
321 				  &otos8, &ip->ip_tos) == 0) {
322 			m_freem(m);
323 			return IPPROTO_DONE;
324 		}
325 		break;
326 	    }
327 #endif /* INET */
328 #ifdef INET6
329 	case IPPROTO_IPV6:
330 	    {
331 		struct ip6_hdr *ip6;
332 		af = AF_INET6;
333 		if (m->m_len < sizeof(*ip6)) {
334 			m = m_pullup(m, sizeof(*ip6));
335 			if (!m)
336 				return IPPROTO_DONE;
337 		}
338 		ip6 = mtod(m, struct ip6_hdr *);
339 		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
340 				   ECN_ALLOWED : ECN_NOCARE,
341 				   &otos, &ip6->ip6_flow) == 0) {
342 			m_freem(m);
343 			return IPPROTO_DONE;
344 		}
345 		break;
346 	    }
347 #endif
348 	case IPPROTO_ETHERIP:
349 		af = AF_LINK;
350 		break;
351 
352 	default:
353 		V_ip6stat.ip6s_nogif++;
354 		m_freem(m);
355 		return IPPROTO_DONE;
356 	}
357 
358 	gif_input(m, af, gifp);
359 	return IPPROTO_DONE;
360 }
361 
362 /*
363  * validate outer address.
364  */
365 static int
366 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
367     struct ifnet *ifp)
368 {
369 	struct sockaddr_in6 *src, *dst;
370 
371 	src = (struct sockaddr_in6 *)sc->gif_psrc;
372 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
373 
374 	/*
375 	 * Check for address match.  Note that the check is for an incoming
376 	 * packet.  We should compare the *source* address in our configuration
377 	 * and the *destination* address of the packet, and vice versa.
378 	 */
379 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
380 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
381 		return 0;
382 
383 	/* martian filters on outer source - done in ip6_input */
384 
385 	/* ingress filters on outer source */
386 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
387 		struct sockaddr_in6 sin6;
388 		struct rtentry *rt;
389 
390 		bzero(&sin6, sizeof(sin6));
391 		sin6.sin6_family = AF_INET6;
392 		sin6.sin6_len = sizeof(struct sockaddr_in6);
393 		sin6.sin6_addr = ip6->ip6_src;
394 		sin6.sin6_scope_id = 0; /* XXX */
395 
396 		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
397 		if (!rt || rt->rt_ifp != ifp) {
398 #if 0
399 			char ip6buf[INET6_ADDRSTRLEN];
400 			log(LOG_WARNING, "%s: packet from %s dropped "
401 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
402 			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
403 #endif
404 			if (rt)
405 				RTFREE_LOCKED(rt);
406 			return 0;
407 		}
408 		RTFREE_LOCKED(rt);
409 	}
410 
411 	return 128 * 2;
412 }
413 
414 /*
415  * we know that we are in IFF_UP, outer address available, and outer family
416  * matched the physical addr family.  see gif_encapcheck().
417  * sanity check for arg should have been done in the caller.
418  */
419 int
420 gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
421 {
422 	struct ip6_hdr ip6;
423 	struct gif_softc *sc;
424 	struct ifnet *ifp;
425 
426 	/* sanity check done in caller */
427 	sc = (struct gif_softc *)arg;
428 
429 	/* LINTED const cast */
430 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
431 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
432 
433 	return gif_validate6(&ip6, sc, ifp);
434 }
435 
436 int
437 in6_gif_attach(struct gif_softc *sc)
438 {
439 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
440 	    (void *)&in6_gif_protosw, sc);
441 	if (sc->encap_cookie6 == NULL)
442 		return EEXIST;
443 	return 0;
444 }
445 
446 int
447 in6_gif_detach(struct gif_softc *sc)
448 {
449 	int error;
450 
451 	error = encap_detach(sc->encap_cookie6);
452 	if (error == 0)
453 		sc->encap_cookie6 = NULL;
454 	return error;
455 }
456