in6_gif.c revision 165118 
1/*	$FreeBSD: head/sys/netinet6/in6_gif.c 165118 2006-12-12 12:17:58Z bz $	*/
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/if_gif.h>
70
71static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
72			 struct ifnet *);
73
74extern  struct domain inet6domain;
75struct ip6protosw in6_gif_protosw =
76{ SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
77  in6_gif_input, rip6_output,	0,		rip6_ctloutput,
78  0,
79  0,		0,		0,		0,
80  &rip6_usrreqs
81};
82
83int
84in6_gif_output(ifp, family, m)
85	struct ifnet *ifp;
86	int family; /* family of the packet to be encapsulate. */
87	struct mbuf *m;
88{
89	struct gif_softc *sc = ifp->if_softc;
90	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
91	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
92	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
93	struct ip6_hdr *ip6;
94	struct etherip_header eiphdr;
95	int proto, error;
96	u_int8_t itos, otos;
97
98	GIF_LOCK_ASSERT(sc);
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	case AF_LINK:
140 		proto = IPPROTO_ETHERIP;
141 		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
142 		eiphdr.eip_pad = 0;
143 		/* prepend Ethernet-in-IP header */
144 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
145 		if (m && m->m_len < sizeof(struct etherip_header))
146 			m = m_pullup(m, sizeof(struct etherip_header));
147 		if (m == NULL)
148 			return ENOBUFS;
149 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
150		    sizeof(struct etherip_header));
151		break;
152
153	default:
154#ifdef DEBUG
155		printf("in6_gif_output: warning: unknown family %d passed\n",
156			family);
157#endif
158		m_freem(m);
159		return EAFNOSUPPORT;
160	}
161
162	/* prepend new IP header */
163	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
164	if (m && m->m_len < sizeof(struct ip6_hdr))
165		m = m_pullup(m, sizeof(struct ip6_hdr));
166	if (m == NULL) {
167		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
168		return ENOBUFS;
169	}
170
171	ip6 = mtod(m, struct ip6_hdr *);
172	ip6->ip6_flow	= 0;
173	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
174	ip6->ip6_vfc	|= IPV6_VERSION;
175	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
176	ip6->ip6_nxt	= proto;
177	ip6->ip6_hlim	= ip6_gif_hlim;
178	ip6->ip6_src	= sin6_src->sin6_addr;
179	/* bidirectional configured tunnel mode */
180	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
181		ip6->ip6_dst = sin6_dst->sin6_addr;
182	else  {
183		m_freem(m);
184		return ENETUNREACH;
185	}
186	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
187		       &otos, &itos);
188	ip6->ip6_flow &= ~htonl(0xff << 20);
189	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
190
191	if (dst->sin6_family != sin6_dst->sin6_family ||
192	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
193		/* cache route doesn't match */
194		bzero(dst, sizeof(*dst));
195		dst->sin6_family = sin6_dst->sin6_family;
196		dst->sin6_len = sizeof(struct sockaddr_in6);
197		dst->sin6_addr = sin6_dst->sin6_addr;
198		if (sc->gif_ro6.ro_rt) {
199			RTFREE(sc->gif_ro6.ro_rt);
200			sc->gif_ro6.ro_rt = NULL;
201		}
202#if 0
203		GIF2IFP(sc)->if_mtu = GIF_MTU;
204#endif
205	}
206
207	if (sc->gif_ro6.ro_rt == NULL) {
208		rtalloc((struct route *)&sc->gif_ro6);
209		if (sc->gif_ro6.ro_rt == NULL) {
210			m_freem(m);
211			return ENETUNREACH;
212		}
213
214		/* if it constitutes infinite encapsulation, punt. */
215		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
216			m_freem(m);
217			return ENETUNREACH;	/*XXX*/
218		}
219#if 0
220		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
221			- sizeof(struct ip6_hdr);
222#endif
223	}
224
225#ifdef IPV6_MINMTU
226	/*
227	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
228	 * it is too painful to ask for resend of inner packet, to achieve
229	 * path MTU discovery for encapsulated packets.
230	 */
231	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
232#else
233	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
234#endif
235
236	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
237	    sc->gif_ro6.ro_rt != NULL) {
238		RTFREE(sc->gif_ro6.ro_rt);
239		sc->gif_ro6.ro_rt = NULL;
240	}
241
242	return (error);
243}
244
245int
246in6_gif_input(mp, offp, proto)
247	struct mbuf **mp;
248	int *offp, proto;
249{
250	struct mbuf *m = *mp;
251	struct ifnet *gifp = NULL;
252	struct gif_softc *sc;
253	struct ip6_hdr *ip6;
254	int af = 0;
255	u_int32_t otos;
256
257	ip6 = mtod(m, struct ip6_hdr *);
258
259	sc = (struct gif_softc *)encap_getarg(m);
260	if (sc == NULL) {
261		m_freem(m);
262		ip6stat.ip6s_nogif++;
263		return IPPROTO_DONE;
264	}
265
266	gifp = GIF2IFP(sc);
267	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
268		m_freem(m);
269		ip6stat.ip6s_nogif++;
270		return IPPROTO_DONE;
271	}
272
273	otos = ip6->ip6_flow;
274	m_adj(m, *offp);
275
276	switch (proto) {
277#ifdef INET
278	case IPPROTO_IPV4:
279	    {
280		struct ip *ip;
281		u_int8_t otos8;
282		af = AF_INET;
283		otos8 = (ntohl(otos) >> 20) & 0xff;
284		if (m->m_len < sizeof(*ip)) {
285			m = m_pullup(m, sizeof(*ip));
286			if (!m)
287				return IPPROTO_DONE;
288		}
289		ip = mtod(m, struct ip *);
290		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
291				  ECN_ALLOWED : ECN_NOCARE,
292				  &otos8, &ip->ip_tos) == 0) {
293			m_freem(m);
294			return IPPROTO_DONE;
295		}
296		break;
297	    }
298#endif /* INET */
299#ifdef INET6
300	case IPPROTO_IPV6:
301	    {
302		struct ip6_hdr *ip6;
303		af = AF_INET6;
304		if (m->m_len < sizeof(*ip6)) {
305			m = m_pullup(m, sizeof(*ip6));
306			if (!m)
307				return IPPROTO_DONE;
308		}
309		ip6 = mtod(m, struct ip6_hdr *);
310		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
311				   ECN_ALLOWED : ECN_NOCARE,
312				   &otos, &ip6->ip6_flow) == 0) {
313			m_freem(m);
314			return IPPROTO_DONE;
315		}
316		break;
317	    }
318#endif
319 	case IPPROTO_ETHERIP:
320 		af = AF_LINK;
321 		break;
322
323	default:
324		ip6stat.ip6s_nogif++;
325		m_freem(m);
326		return IPPROTO_DONE;
327	}
328
329	gif_input(m, af, gifp);
330	return IPPROTO_DONE;
331}
332
333/*
334 * validate outer address.
335 */
336static int
337gif_validate6(ip6, sc, ifp)
338	const struct ip6_hdr *ip6;
339	struct gif_softc *sc;
340	struct ifnet *ifp;
341{
342	struct sockaddr_in6 *src, *dst;
343
344	src = (struct sockaddr_in6 *)sc->gif_psrc;
345	dst = (struct sockaddr_in6 *)sc->gif_pdst;
346
347	/*
348	 * Check for address match.  Note that the check is for an incoming
349	 * packet.  We should compare the *source* address in our configuration
350	 * and the *destination* address of the packet, and vice versa.
351	 */
352	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
353	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
354		return 0;
355
356	/* martian filters on outer source - done in ip6_input */
357
358	/* ingress filters on outer source */
359	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
360		struct sockaddr_in6 sin6;
361		struct rtentry *rt;
362
363		bzero(&sin6, sizeof(sin6));
364		sin6.sin6_family = AF_INET6;
365		sin6.sin6_len = sizeof(struct sockaddr_in6);
366		sin6.sin6_addr = ip6->ip6_src;
367		sin6.sin6_scope_id = 0; /* XXX */
368
369		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
370		if (!rt || rt->rt_ifp != ifp) {
371#if 0
372			char ip6buf[INET6_ADDRSTRLEN];
373			log(LOG_WARNING, "%s: packet from %s dropped "
374			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
375			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
376#endif
377			if (rt)
378				rtfree(rt);
379			return 0;
380		}
381		rtfree(rt);
382	}
383
384	return 128 * 2;
385}
386
387/*
388 * we know that we are in IFF_UP, outer address available, and outer family
389 * matched the physical addr family.  see gif_encapcheck().
390 * sanity check for arg should have been done in the caller.
391 */
392int
393gif_encapcheck6(m, off, proto, arg)
394	const struct mbuf *m;
395	int off;
396	int proto;
397	void *arg;
398{
399	struct ip6_hdr ip6;
400	struct gif_softc *sc;
401	struct ifnet *ifp;
402
403	/* sanity check done in caller */
404	sc = (struct gif_softc *)arg;
405
406	/* LINTED const cast */
407	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
408	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
409
410	return gif_validate6(&ip6, sc, ifp);
411}
412
413int
414in6_gif_attach(sc)
415	struct gif_softc *sc;
416{
417	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
418	    (void *)&in6_gif_protosw, sc);
419	if (sc->encap_cookie6 == NULL)
420		return EEXIST;
421	return 0;
422}
423
424int
425in6_gif_detach(sc)
426	struct gif_softc *sc;
427{
428	int error;
429
430	error = encap_detach(sc->encap_cookie6);
431	if (error == 0)
432		sc->encap_cookie6 = NULL;
433	return error;
434}
435