in6_gif.c revision 186751 
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: head/sys/netinet6/in6_gif.c 186751 2009-01-04 21:53:42Z rwatson $");
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#include <sys/vimage.h>
49
50#include <net/if.h>
51#include <net/route.h>
52
53#include <netinet/in.h>
54#include <netinet/in_systm.h>
55#ifdef INET
56#include <netinet/ip.h>
57#endif
58#include <netinet/ip_encap.h>
59#ifdef INET6
60#include <netinet/ip6.h>
61#include <netinet6/ip6_var.h>
62#include <netinet6/in6_gif.h>
63#include <netinet6/in6_var.h>
64#endif
65#include <netinet6/ip6protosw.h>
66#include <netinet/ip_ecn.h>
67#ifdef INET6
68#include <netinet6/ip6_ecn.h>
69#include <netinet6/vinet6.h>
70#endif
71
72#include <net/if_gif.h>
73
74static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
75			 struct ifnet *);
76
77extern  struct domain inet6domain;
78struct ip6protosw in6_gif_protosw =
79{ SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
80  in6_gif_input, rip6_output,	0,		rip6_ctloutput,
81  0,		0,		0,		0,
82  &rip6_usrreqs
83};
84
85int
86in6_gif_output(struct ifnet *ifp,
87    int family,			/* family of the packet to be encapsulate */
88    struct mbuf *m)
89{
90	INIT_VNET_GIF(ifp->if_vnet);
91	struct gif_softc *sc = ifp->if_softc;
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	struct etherip_header eiphdr;
97	int proto, error;
98	u_int8_t itos, otos;
99
100	GIF_LOCK_ASSERT(sc);
101
102	if (sin6_src == NULL || sin6_dst == NULL ||
103	    sin6_src->sin6_family != AF_INET6 ||
104	    sin6_dst->sin6_family != AF_INET6) {
105		m_freem(m);
106		return EAFNOSUPPORT;
107	}
108
109	switch (family) {
110#ifdef INET
111	case AF_INET:
112	    {
113		struct ip *ip;
114
115		proto = IPPROTO_IPV4;
116		if (m->m_len < sizeof(*ip)) {
117			m = m_pullup(m, sizeof(*ip));
118			if (!m)
119				return ENOBUFS;
120		}
121		ip = mtod(m, struct ip *);
122		itos = ip->ip_tos;
123		break;
124	    }
125#endif
126#ifdef INET6
127	case AF_INET6:
128	    {
129		struct ip6_hdr *ip6;
130		proto = IPPROTO_IPV6;
131		if (m->m_len < sizeof(*ip6)) {
132			m = m_pullup(m, sizeof(*ip6));
133			if (!m)
134				return ENOBUFS;
135		}
136		ip6 = mtod(m, struct ip6_hdr *);
137		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
138		break;
139	    }
140#endif
141	case AF_LINK:
142		proto = IPPROTO_ETHERIP;
143		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
144		eiphdr.eip_pad = 0;
145		/* prepend Ethernet-in-IP header */
146		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
147		if (m && m->m_len < sizeof(struct etherip_header))
148			m = m_pullup(m, sizeof(struct etherip_header));
149		if (m == NULL)
150			return ENOBUFS;
151		bcopy(&eiphdr, mtod(m, struct etherip_header *),
152		    sizeof(struct etherip_header));
153		break;
154
155	default:
156#ifdef DEBUG
157		printf("in6_gif_output: warning: unknown family %d passed\n",
158			family);
159#endif
160		m_freem(m);
161		return EAFNOSUPPORT;
162	}
163
164	/* prepend new IP header */
165	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
166	if (m && m->m_len < sizeof(struct ip6_hdr))
167		m = m_pullup(m, sizeof(struct ip6_hdr));
168	if (m == NULL) {
169		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
170		return ENOBUFS;
171	}
172
173	ip6 = mtod(m, struct ip6_hdr *);
174	ip6->ip6_flow	= 0;
175	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
176	ip6->ip6_vfc	|= IPV6_VERSION;
177	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
178	ip6->ip6_nxt	= proto;
179	ip6->ip6_hlim	= V_ip6_gif_hlim;
180	ip6->ip6_src	= sin6_src->sin6_addr;
181	/* bidirectional configured tunnel mode */
182	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
183		ip6->ip6_dst = sin6_dst->sin6_addr;
184	else  {
185		m_freem(m);
186		return ENETUNREACH;
187	}
188	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
189		       &otos, &itos);
190	ip6->ip6_flow &= ~htonl(0xff << 20);
191	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
192
193	if (dst->sin6_family != sin6_dst->sin6_family ||
194	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
195		/* cache route doesn't match */
196		bzero(dst, sizeof(*dst));
197		dst->sin6_family = sin6_dst->sin6_family;
198		dst->sin6_len = sizeof(struct sockaddr_in6);
199		dst->sin6_addr = sin6_dst->sin6_addr;
200		if (sc->gif_ro6.ro_rt) {
201			RTFREE(sc->gif_ro6.ro_rt);
202			sc->gif_ro6.ro_rt = NULL;
203		}
204#if 0
205		GIF2IFP(sc)->if_mtu = GIF_MTU;
206#endif
207	}
208
209	if (sc->gif_ro6.ro_rt == NULL) {
210		rtalloc((struct route *)&sc->gif_ro6);
211		if (sc->gif_ro6.ro_rt == NULL) {
212			m_freem(m);
213			return ENETUNREACH;
214		}
215
216		/* if it constitutes infinite encapsulation, punt. */
217		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
218			m_freem(m);
219			return ENETUNREACH;	/*XXX*/
220		}
221#if 0
222		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
223			- sizeof(struct ip6_hdr);
224#endif
225	}
226
227#ifdef IPV6_MINMTU
228	/*
229	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
230	 * it is too painful to ask for resend of inner packet, to achieve
231	 * path MTU discovery for encapsulated packets.
232	 */
233	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
234#else
235	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
236#endif
237
238	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
239	    sc->gif_ro6.ro_rt != NULL) {
240		RTFREE(sc->gif_ro6.ro_rt);
241		sc->gif_ro6.ro_rt = NULL;
242	}
243
244	return (error);
245}
246
247int
248in6_gif_input(struct mbuf **mp, int *offp, int proto)
249{
250	INIT_VNET_INET6(curvnet);
251	struct mbuf *m = *mp;
252	struct ifnet *gifp = NULL;
253	struct gif_softc *sc;
254	struct ip6_hdr *ip6;
255	int af = 0;
256	u_int32_t otos;
257
258	ip6 = mtod(m, struct ip6_hdr *);
259
260	sc = (struct gif_softc *)encap_getarg(m);
261	if (sc == NULL) {
262		m_freem(m);
263		V_ip6stat.ip6s_nogif++;
264		return IPPROTO_DONE;
265	}
266
267	gifp = GIF2IFP(sc);
268	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
269		m_freem(m);
270		V_ip6stat.ip6s_nogif++;
271		return IPPROTO_DONE;
272	}
273
274	otos = ip6->ip6_flow;
275	m_adj(m, *offp);
276
277	switch (proto) {
278#ifdef INET
279	case IPPROTO_IPV4:
280	    {
281		struct ip *ip;
282		u_int8_t otos8;
283		af = AF_INET;
284		otos8 = (ntohl(otos) >> 20) & 0xff;
285		if (m->m_len < sizeof(*ip)) {
286			m = m_pullup(m, sizeof(*ip));
287			if (!m)
288				return IPPROTO_DONE;
289		}
290		ip = mtod(m, struct ip *);
291		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
292				  ECN_ALLOWED : ECN_NOCARE,
293				  &otos8, &ip->ip_tos) == 0) {
294			m_freem(m);
295			return IPPROTO_DONE;
296		}
297		break;
298	    }
299#endif /* INET */
300#ifdef INET6
301	case IPPROTO_IPV6:
302	    {
303		struct ip6_hdr *ip6;
304		af = AF_INET6;
305		if (m->m_len < sizeof(*ip6)) {
306			m = m_pullup(m, sizeof(*ip6));
307			if (!m)
308				return IPPROTO_DONE;
309		}
310		ip6 = mtod(m, struct ip6_hdr *);
311		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
312				   ECN_ALLOWED : ECN_NOCARE,
313				   &otos, &ip6->ip6_flow) == 0) {
314			m_freem(m);
315			return IPPROTO_DONE;
316		}
317		break;
318	    }
319#endif
320	case IPPROTO_ETHERIP:
321		af = AF_LINK;
322		break;
323
324	default:
325		V_ip6stat.ip6s_nogif++;
326		m_freem(m);
327		return IPPROTO_DONE;
328	}
329
330	gif_input(m, af, gifp);
331	return IPPROTO_DONE;
332}
333
334/*
335 * validate outer address.
336 */
337static int
338gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
339    struct ifnet *ifp)
340{
341	struct sockaddr_in6 *src, *dst;
342
343	src = (struct sockaddr_in6 *)sc->gif_psrc;
344	dst = (struct sockaddr_in6 *)sc->gif_pdst;
345
346	/*
347	 * Check for address match.  Note that the check is for an incoming
348	 * packet.  We should compare the *source* address in our configuration
349	 * and the *destination* address of the packet, and vice versa.
350	 */
351	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
352	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
353		return 0;
354
355	/* martian filters on outer source - done in ip6_input */
356
357	/* ingress filters on outer source */
358	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
359		struct sockaddr_in6 sin6;
360		struct rtentry *rt;
361
362		bzero(&sin6, sizeof(sin6));
363		sin6.sin6_family = AF_INET6;
364		sin6.sin6_len = sizeof(struct sockaddr_in6);
365		sin6.sin6_addr = ip6->ip6_src;
366		sin6.sin6_scope_id = 0; /* XXX */
367
368		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
369		if (!rt || rt->rt_ifp != ifp) {
370#if 0
371			char ip6buf[INET6_ADDRSTRLEN];
372			log(LOG_WARNING, "%s: packet from %s dropped "
373			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
374			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
375#endif
376			if (rt)
377				rtfree(rt);
378			return 0;
379		}
380		rtfree(rt);
381	}
382
383	return 128 * 2;
384}
385
386/*
387 * we know that we are in IFF_UP, outer address available, and outer family
388 * matched the physical addr family.  see gif_encapcheck().
389 * sanity check for arg should have been done in the caller.
390 */
391int
392gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
393{
394	struct ip6_hdr ip6;
395	struct gif_softc *sc;
396	struct ifnet *ifp;
397
398	/* sanity check done in caller */
399	sc = (struct gif_softc *)arg;
400
401	/* LINTED const cast */
402	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
403	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
404
405	return gif_validate6(&ip6, sc, ifp);
406}
407
408int
409in6_gif_attach(struct gif_softc *sc)
410{
411	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
412	    (void *)&in6_gif_protosw, sc);
413	if (sc->encap_cookie6 == NULL)
414		return EEXIST;
415	return 0;
416}
417
418int
419in6_gif_detach(struct gif_softc *sc)
420{
421	int error;
422
423	error = encap_detach(sc->encap_cookie6);
424	if (error == 0)
425		sc->encap_cookie6 = NULL;
426	return error;
427}
428