in6_gif.c revision 226b2a700eecfdf598bf77f229d3a378d11844b4
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#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	.pr_type =	SOCK_RAW,
80	.pr_domain =	&inet6domain,
81	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
82	.pr_flags =	PR_ATOMIC|PR_ADDR,
83	.pr_input =	in6_gif_input,
84	.pr_output =	rip6_output,
85	.pr_ctloutput =	rip6_ctloutput,
86	.pr_usrreqs =	&rip6_usrreqs
87};
88
89int
90in6_gif_output(struct ifnet *ifp,
91    int family,			/* family of the packet to be encapsulate */
92    struct mbuf *m)
93{
94	INIT_VNET_GIF(ifp->if_vnet);
95	struct gif_softc *sc = ifp->if_softc;
96	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
97	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
98	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
99	struct ip6_hdr *ip6;
100	struct etherip_header eiphdr;
101	int proto, error;
102	u_int8_t itos, otos;
103
104	GIF_LOCK_ASSERT(sc);
105
106	if (sin6_src == NULL || sin6_dst == NULL ||
107	    sin6_src->sin6_family != AF_INET6 ||
108	    sin6_dst->sin6_family != AF_INET6) {
109		m_freem(m);
110		return EAFNOSUPPORT;
111	}
112
113	switch (family) {
114#ifdef INET
115	case AF_INET:
116	    {
117		struct ip *ip;
118
119		proto = IPPROTO_IPV4;
120		if (m->m_len < sizeof(*ip)) {
121			m = m_pullup(m, sizeof(*ip));
122			if (!m)
123				return ENOBUFS;
124		}
125		ip = mtod(m, struct ip *);
126		itos = ip->ip_tos;
127		break;
128	    }
129#endif
130#ifdef INET6
131	case AF_INET6:
132	    {
133		struct ip6_hdr *ip6;
134		proto = IPPROTO_IPV6;
135		if (m->m_len < sizeof(*ip6)) {
136			m = m_pullup(m, sizeof(*ip6));
137			if (!m)
138				return ENOBUFS;
139		}
140		ip6 = mtod(m, struct ip6_hdr *);
141		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
142		break;
143	    }
144#endif
145	case AF_LINK:
146		proto = IPPROTO_ETHERIP;
147		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
148		eiphdr.eip_pad = 0;
149		/* prepend Ethernet-in-IP header */
150		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
151		if (m && m->m_len < sizeof(struct etherip_header))
152			m = m_pullup(m, sizeof(struct etherip_header));
153		if (m == NULL)
154			return ENOBUFS;
155		bcopy(&eiphdr, mtod(m, struct etherip_header *),
156		    sizeof(struct etherip_header));
157		break;
158
159	default:
160#ifdef DEBUG
161		printf("in6_gif_output: warning: unknown family %d passed\n",
162			family);
163#endif
164		m_freem(m);
165		return EAFNOSUPPORT;
166	}
167
168	/* prepend new IP header */
169	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
170	if (m && m->m_len < sizeof(struct ip6_hdr))
171		m = m_pullup(m, sizeof(struct ip6_hdr));
172	if (m == NULL) {
173		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
174		return ENOBUFS;
175	}
176
177	ip6 = mtod(m, struct ip6_hdr *);
178	ip6->ip6_flow	= 0;
179	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
180	ip6->ip6_vfc	|= IPV6_VERSION;
181	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
182	ip6->ip6_nxt	= proto;
183	ip6->ip6_hlim	= V_ip6_gif_hlim;
184	ip6->ip6_src	= sin6_src->sin6_addr;
185	/* bidirectional configured tunnel mode */
186	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
187		ip6->ip6_dst = sin6_dst->sin6_addr;
188	else  {
189		m_freem(m);
190		return ENETUNREACH;
191	}
192	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
193		       &otos, &itos);
194	ip6->ip6_flow &= ~htonl(0xff << 20);
195	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
196
197	if (dst->sin6_family != sin6_dst->sin6_family ||
198	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
199		/* cache route doesn't match */
200		bzero(dst, sizeof(*dst));
201		dst->sin6_family = sin6_dst->sin6_family;
202		dst->sin6_len = sizeof(struct sockaddr_in6);
203		dst->sin6_addr = sin6_dst->sin6_addr;
204		if (sc->gif_ro6.ro_rt) {
205			RTFREE(sc->gif_ro6.ro_rt);
206			sc->gif_ro6.ro_rt = NULL;
207		}
208#if 0
209		GIF2IFP(sc)->if_mtu = GIF_MTU;
210#endif
211	}
212
213	if (sc->gif_ro6.ro_rt == NULL) {
214		rtalloc((struct route *)&sc->gif_ro6);
215		if (sc->gif_ro6.ro_rt == NULL) {
216			m_freem(m);
217			return ENETUNREACH;
218		}
219
220		/* if it constitutes infinite encapsulation, punt. */
221		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
222			m_freem(m);
223			return ENETUNREACH;	/*XXX*/
224		}
225#if 0
226		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
227			- sizeof(struct ip6_hdr);
228#endif
229	}
230
231#ifdef IPV6_MINMTU
232	/*
233	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
234	 * it is too painful to ask for resend of inner packet, to achieve
235	 * path MTU discovery for encapsulated packets.
236	 */
237	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
238#else
239	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
240#endif
241
242	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
243	    sc->gif_ro6.ro_rt != NULL) {
244		RTFREE(sc->gif_ro6.ro_rt);
245		sc->gif_ro6.ro_rt = NULL;
246	}
247
248	return (error);
249}
250
251int
252in6_gif_input(struct mbuf **mp, int *offp, int proto)
253{
254	INIT_VNET_INET6(curvnet);
255	struct mbuf *m = *mp;
256	struct ifnet *gifp = NULL;
257	struct gif_softc *sc;
258	struct ip6_hdr *ip6;
259	int af = 0;
260	u_int32_t otos;
261
262	ip6 = mtod(m, struct ip6_hdr *);
263
264	sc = (struct gif_softc *)encap_getarg(m);
265	if (sc == NULL) {
266		m_freem(m);
267		V_ip6stat.ip6s_nogif++;
268		return IPPROTO_DONE;
269	}
270
271	gifp = GIF2IFP(sc);
272	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
273		m_freem(m);
274		V_ip6stat.ip6s_nogif++;
275		return IPPROTO_DONE;
276	}
277
278	otos = ip6->ip6_flow;
279	m_adj(m, *offp);
280
281	switch (proto) {
282#ifdef INET
283	case IPPROTO_IPV4:
284	    {
285		struct ip *ip;
286		u_int8_t otos8;
287		af = AF_INET;
288		otos8 = (ntohl(otos) >> 20) & 0xff;
289		if (m->m_len < sizeof(*ip)) {
290			m = m_pullup(m, sizeof(*ip));
291			if (!m)
292				return IPPROTO_DONE;
293		}
294		ip = mtod(m, struct ip *);
295		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
296				  ECN_ALLOWED : ECN_NOCARE,
297				  &otos8, &ip->ip_tos) == 0) {
298			m_freem(m);
299			return IPPROTO_DONE;
300		}
301		break;
302	    }
303#endif /* INET */
304#ifdef INET6
305	case IPPROTO_IPV6:
306	    {
307		struct ip6_hdr *ip6;
308		af = AF_INET6;
309		if (m->m_len < sizeof(*ip6)) {
310			m = m_pullup(m, sizeof(*ip6));
311			if (!m)
312				return IPPROTO_DONE;
313		}
314		ip6 = mtod(m, struct ip6_hdr *);
315		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
316				   ECN_ALLOWED : ECN_NOCARE,
317				   &otos, &ip6->ip6_flow) == 0) {
318			m_freem(m);
319			return IPPROTO_DONE;
320		}
321		break;
322	    }
323#endif
324	case IPPROTO_ETHERIP:
325		af = AF_LINK;
326		break;
327
328	default:
329		V_ip6stat.ip6s_nogif++;
330		m_freem(m);
331		return IPPROTO_DONE;
332	}
333
334	gif_input(m, af, gifp);
335	return IPPROTO_DONE;
336}
337
338/*
339 * validate outer address.
340 */
341static int
342gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
343    struct ifnet *ifp)
344{
345	struct sockaddr_in6 *src, *dst;
346
347	src = (struct sockaddr_in6 *)sc->gif_psrc;
348	dst = (struct sockaddr_in6 *)sc->gif_pdst;
349
350	/*
351	 * Check for address match.  Note that the check is for an incoming
352	 * packet.  We should compare the *source* address in our configuration
353	 * and the *destination* address of the packet, and vice versa.
354	 */
355	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
356	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
357		return 0;
358
359	/* martian filters on outer source - done in ip6_input */
360
361	/* ingress filters on outer source */
362	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
363		struct sockaddr_in6 sin6;
364		struct rtentry *rt;
365
366		bzero(&sin6, sizeof(sin6));
367		sin6.sin6_family = AF_INET6;
368		sin6.sin6_len = sizeof(struct sockaddr_in6);
369		sin6.sin6_addr = ip6->ip6_src;
370		sin6.sin6_scope_id = 0; /* XXX */
371
372		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
373		if (!rt || rt->rt_ifp != ifp) {
374#if 0
375			char ip6buf[INET6_ADDRSTRLEN];
376			log(LOG_WARNING, "%s: packet from %s dropped "
377			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
378			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
379#endif
380			if (rt)
381				RTFREE_LOCKED(rt);
382			return 0;
383		}
384		RTFREE_LOCKED(rt);
385	}
386
387	return 128 * 2;
388}
389
390/*
391 * we know that we are in IFF_UP, outer address available, and outer family
392 * matched the physical addr family.  see gif_encapcheck().
393 * sanity check for arg should have been done in the caller.
394 */
395int
396gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
397{
398	struct ip6_hdr ip6;
399	struct gif_softc *sc;
400	struct ifnet *ifp;
401
402	/* sanity check done in caller */
403	sc = (struct gif_softc *)arg;
404
405	/* LINTED const cast */
406	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
407	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
408
409	return gif_validate6(&ip6, sc, ifp);
410}
411
412int
413in6_gif_attach(struct gif_softc *sc)
414{
415	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
416	    (void *)&in6_gif_protosw, sc);
417	if (sc->encap_cookie6 == NULL)
418		return EEXIST;
419	return 0;
420}
421
422int
423in6_gif_detach(struct gif_softc *sc)
424{
425	int error;
426
427	error = encap_detach(sc->encap_cookie6);
428	if (error == 0)
429		sc->encap_cookie6 = NULL;
430	return error;
431}
432