in6_gif.c revision 121684 
1/*	$FreeBSD: head/sys/netinet6/in6_gif.c 121684 2003-10-29 15:07:04Z ume $	*/
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
71#include <net/net_osdep.h>
72
73static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
74			 struct ifnet *);
75
76extern  struct domain inet6domain;
77struct ip6protosw in6_gif_protosw =
78{ SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
79  in6_gif_input, rip6_output,	0,		rip6_ctloutput,
80  0,
81  0,		0,		0,		0,
82  &rip6_usrreqs
83};
84
85int
86in6_gif_output(ifp, family, m)
87	struct ifnet *ifp;
88	int family; /* family of the packet to be encapsulate. */
89	struct mbuf *m;
90{
91	struct gif_softc *sc = (struct gif_softc*)ifp;
92	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
93	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
94	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
95	struct ip6_hdr *ip6;
96	int proto;
97	u_int8_t itos, otos;
98
99	if (sin6_src == NULL || sin6_dst == NULL ||
100	    sin6_src->sin6_family != AF_INET6 ||
101	    sin6_dst->sin6_family != AF_INET6) {
102		m_freem(m);
103		return EAFNOSUPPORT;
104	}
105
106	switch (family) {
107#ifdef INET
108	case AF_INET:
109	    {
110		struct ip *ip;
111
112		proto = IPPROTO_IPV4;
113		if (m->m_len < sizeof(*ip)) {
114			m = m_pullup(m, sizeof(*ip));
115			if (!m)
116				return ENOBUFS;
117		}
118		ip = mtod(m, struct ip *);
119		itos = ip->ip_tos;
120		break;
121	    }
122#endif
123#ifdef INET6
124	case AF_INET6:
125	    {
126		struct ip6_hdr *ip6;
127		proto = IPPROTO_IPV6;
128		if (m->m_len < sizeof(*ip6)) {
129			m = m_pullup(m, sizeof(*ip6));
130			if (!m)
131				return ENOBUFS;
132		}
133		ip6 = mtod(m, struct ip6_hdr *);
134		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
135		break;
136	    }
137#endif
138	default:
139#ifdef DEBUG
140		printf("in6_gif_output: warning: unknown family %d passed\n",
141			family);
142#endif
143		m_freem(m);
144		return EAFNOSUPPORT;
145	}
146
147	/* prepend new IP header */
148	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
149	if (m && m->m_len < sizeof(struct ip6_hdr))
150		m = m_pullup(m, sizeof(struct ip6_hdr));
151	if (m == NULL) {
152		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
153		return ENOBUFS;
154	}
155
156	ip6 = mtod(m, struct ip6_hdr *);
157	ip6->ip6_flow	= 0;
158	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
159	ip6->ip6_vfc	|= IPV6_VERSION;
160	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
161	ip6->ip6_nxt	= proto;
162	ip6->ip6_hlim	= ip6_gif_hlim;
163	ip6->ip6_src	= sin6_src->sin6_addr;
164	/* bidirectional configured tunnel mode */
165	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
166		ip6->ip6_dst = sin6_dst->sin6_addr;
167	else  {
168		m_freem(m);
169		return ENETUNREACH;
170	}
171	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
172		       &otos, &itos);
173	ip6->ip6_flow &= ~htonl(0xff << 20);
174	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
175
176	if (dst->sin6_family != sin6_dst->sin6_family ||
177	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
178		/* cache route doesn't match */
179		bzero(dst, sizeof(*dst));
180		dst->sin6_family = sin6_dst->sin6_family;
181		dst->sin6_len = sizeof(struct sockaddr_in6);
182		dst->sin6_addr = sin6_dst->sin6_addr;
183		if (sc->gif_ro6.ro_rt) {
184			RTFREE(sc->gif_ro6.ro_rt);
185			sc->gif_ro6.ro_rt = NULL;
186		}
187#if 0
188		sc->gif_if.if_mtu = GIF_MTU;
189#endif
190	}
191
192	if (sc->gif_ro6.ro_rt == NULL) {
193		rtalloc((struct route *)&sc->gif_ro6);
194		if (sc->gif_ro6.ro_rt == NULL) {
195			m_freem(m);
196			return ENETUNREACH;
197		}
198
199		/* if it constitutes infinite encapsulation, punt. */
200		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
201			m_freem(m);
202			return ENETUNREACH;	/*XXX*/
203		}
204#if 0
205		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
206			- sizeof(struct ip6_hdr);
207#endif
208	}
209
210#ifdef IPV6_MINMTU
211	/*
212	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
213	 * it is too painful to ask for resend of inner packet, to achieve
214	 * path MTU discovery for encapsulated packets.
215	 */
216	return (ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL));
217#else
218	return (ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL));
219#endif
220}
221
222int
223in6_gif_input(mp, offp, proto)
224	struct mbuf **mp;
225	int *offp, proto;
226{
227	struct mbuf *m = *mp;
228	struct ifnet *gifp = NULL;
229	struct ip6_hdr *ip6;
230	int af = 0;
231	u_int32_t otos;
232
233	ip6 = mtod(m, struct ip6_hdr *);
234
235	gifp = (struct ifnet *)encap_getarg(m);
236
237	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
238		m_freem(m);
239		ip6stat.ip6s_nogif++;
240		return IPPROTO_DONE;
241	}
242
243	otos = ip6->ip6_flow;
244	m_adj(m, *offp);
245
246	switch (proto) {
247#ifdef INET
248	case IPPROTO_IPV4:
249	    {
250		struct ip *ip;
251		u_int8_t otos8;
252		af = AF_INET;
253		otos8 = (ntohl(otos) >> 20) & 0xff;
254		if (m->m_len < sizeof(*ip)) {
255			m = m_pullup(m, sizeof(*ip));
256			if (!m)
257				return IPPROTO_DONE;
258		}
259		ip = mtod(m, struct ip *);
260		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
261				  ECN_ALLOWED : ECN_NOCARE,
262				  &otos8, &ip->ip_tos) == 0) {
263			m_freem(m);
264			return IPPROTO_DONE;
265		}
266		break;
267	    }
268#endif /* INET */
269#ifdef INET6
270	case IPPROTO_IPV6:
271	    {
272		struct ip6_hdr *ip6;
273		af = AF_INET6;
274		if (m->m_len < sizeof(*ip6)) {
275			m = m_pullup(m, sizeof(*ip6));
276			if (!m)
277				return IPPROTO_DONE;
278		}
279		ip6 = mtod(m, struct ip6_hdr *);
280		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
281				   ECN_ALLOWED : ECN_NOCARE,
282				   &otos, &ip6->ip6_flow) == 0) {
283			m_freem(m);
284			return IPPROTO_DONE;
285		}
286		break;
287	    }
288#endif
289	default:
290		ip6stat.ip6s_nogif++;
291		m_freem(m);
292		return IPPROTO_DONE;
293	}
294
295	gif_input(m, af, gifp);
296	return IPPROTO_DONE;
297}
298
299/*
300 * validate outer address.
301 */
302static int
303gif_validate6(ip6, sc, ifp)
304	const struct ip6_hdr *ip6;
305	struct gif_softc *sc;
306	struct ifnet *ifp;
307{
308	struct sockaddr_in6 *src, *dst;
309
310	src = (struct sockaddr_in6 *)sc->gif_psrc;
311	dst = (struct sockaddr_in6 *)sc->gif_pdst;
312
313	/*
314	 * Check for address match.  Note that the check is for an incoming
315	 * packet.  We should compare the *source* address in our configuration
316	 * and the *destination* address of the packet, and vice versa.
317	 */
318	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
319	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
320		return 0;
321
322	/* martian filters on outer source - done in ip6_input */
323
324	/* ingress filters on outer source */
325	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
326		struct sockaddr_in6 sin6;
327		struct rtentry *rt;
328
329		bzero(&sin6, sizeof(sin6));
330		sin6.sin6_family = AF_INET6;
331		sin6.sin6_len = sizeof(struct sockaddr_in6);
332		sin6.sin6_addr = ip6->ip6_src;
333		sin6.sin6_scope_id = 0; /* XXX */
334
335		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
336		if (!rt || rt->rt_ifp != ifp) {
337#if 0
338			log(LOG_WARNING, "%s: packet from %s dropped "
339			    "due to ingress filter\n", if_name(&sc->gif_if),
340			    ip6_sprintf(&sin6.sin6_addr));
341#endif
342			if (rt)
343				rtfree(rt);
344			return 0;
345		}
346		rtfree(rt);
347	}
348
349	return 128 * 2;
350}
351
352/*
353 * we know that we are in IFF_UP, outer address available, and outer family
354 * matched the physical addr family.  see gif_encapcheck().
355 * sanity check for arg should have been done in the caller.
356 */
357int
358gif_encapcheck6(m, off, proto, arg)
359	const struct mbuf *m;
360	int off;
361	int proto;
362	void *arg;
363{
364	struct ip6_hdr ip6;
365	struct gif_softc *sc;
366	struct ifnet *ifp;
367
368	/* sanity check done in caller */
369	sc = (struct gif_softc *)arg;
370
371	/* LINTED const cast */
372	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
373	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
374
375	return gif_validate6(&ip6, sc, ifp);
376}
377
378int
379in6_gif_attach(sc)
380	struct gif_softc *sc;
381{
382	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
383	    (struct protosw *)&in6_gif_protosw, sc);
384	if (sc->encap_cookie6 == NULL)
385		return EEXIST;
386	return 0;
387}
388
389int
390in6_gif_detach(sc)
391	struct gif_softc *sc;
392{
393	int error;
394
395	error = encap_detach(sc->encap_cookie6);
396	if (error == 0)
397		sc->encap_cookie6 = NULL;
398	return error;
399}
400