in6_gif.c revision c625a748346cd7e33dd8e74188155f45a1f83a02
1/*	$FreeBSD$	*/
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 = 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	= 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(mp, offp, proto)
249	struct mbuf **mp;
250	int *offp, proto;
251{
252	struct mbuf *m = *mp;
253	struct ifnet *gifp = NULL;
254	struct gif_softc *sc;
255	struct ip6_hdr *ip6;
256	int af = 0;
257	u_int32_t otos;
258
259	ip6 = mtod(m, struct ip6_hdr *);
260
261	sc = (struct gif_softc *)encap_getarg(m);
262	if (sc == NULL) {
263		m_freem(m);
264		ip6stat.ip6s_nogif++;
265		return IPPROTO_DONE;
266	}
267
268	gifp = GIF2IFP(sc);
269	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
270		m_freem(m);
271		ip6stat.ip6s_nogif++;
272		return IPPROTO_DONE;
273	}
274
275	otos = ip6->ip6_flow;
276	m_adj(m, *offp);
277
278	switch (proto) {
279#ifdef INET
280	case IPPROTO_IPV4:
281	    {
282		struct ip *ip;
283		u_int8_t otos8;
284		af = AF_INET;
285		otos8 = (ntohl(otos) >> 20) & 0xff;
286		if (m->m_len < sizeof(*ip)) {
287			m = m_pullup(m, sizeof(*ip));
288			if (!m)
289				return IPPROTO_DONE;
290		}
291		ip = mtod(m, struct ip *);
292		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
293				  ECN_ALLOWED : ECN_NOCARE,
294				  &otos8, &ip->ip_tos) == 0) {
295			m_freem(m);
296			return IPPROTO_DONE;
297		}
298		break;
299	    }
300#endif /* INET */
301#ifdef INET6
302	case IPPROTO_IPV6:
303	    {
304		struct ip6_hdr *ip6;
305		af = AF_INET6;
306		if (m->m_len < sizeof(*ip6)) {
307			m = m_pullup(m, sizeof(*ip6));
308			if (!m)
309				return IPPROTO_DONE;
310		}
311		ip6 = mtod(m, struct ip6_hdr *);
312		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
313				   ECN_ALLOWED : ECN_NOCARE,
314				   &otos, &ip6->ip6_flow) == 0) {
315			m_freem(m);
316			return IPPROTO_DONE;
317		}
318		break;
319	    }
320#endif
321 	case IPPROTO_ETHERIP:
322 		af = AF_LINK;
323 		break;
324
325	default:
326		ip6stat.ip6s_nogif++;
327		m_freem(m);
328		return IPPROTO_DONE;
329	}
330
331	gif_input(m, af, gifp);
332	return IPPROTO_DONE;
333}
334
335/*
336 * validate outer address.
337 */
338static int
339gif_validate6(ip6, sc, ifp)
340	const struct ip6_hdr *ip6;
341	struct gif_softc *sc;
342	struct ifnet *ifp;
343{
344	struct sockaddr_in6 *src, *dst;
345
346	src = (struct sockaddr_in6 *)sc->gif_psrc;
347	dst = (struct sockaddr_in6 *)sc->gif_pdst;
348
349	/*
350	 * Check for address match.  Note that the check is for an incoming
351	 * packet.  We should compare the *source* address in our configuration
352	 * and the *destination* address of the packet, and vice versa.
353	 */
354	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
355	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
356		return 0;
357
358	/* martian filters on outer source - done in ip6_input */
359
360	/* ingress filters on outer source */
361	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
362		struct sockaddr_in6 sin6;
363		struct rtentry *rt;
364
365		bzero(&sin6, sizeof(sin6));
366		sin6.sin6_family = AF_INET6;
367		sin6.sin6_len = sizeof(struct sockaddr_in6);
368		sin6.sin6_addr = ip6->ip6_src;
369		sin6.sin6_scope_id = 0; /* XXX */
370
371		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
372		if (!rt || rt->rt_ifp != ifp) {
373#if 0
374			log(LOG_WARNING, "%s: packet from %s dropped "
375			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
376			    ip6_sprintf(&sin6.sin6_addr));
377#endif
378			if (rt)
379				rtfree(rt);
380			return 0;
381		}
382		rtfree(rt);
383	}
384
385	return 128 * 2;
386}
387
388/*
389 * we know that we are in IFF_UP, outer address available, and outer family
390 * matched the physical addr family.  see gif_encapcheck().
391 * sanity check for arg should have been done in the caller.
392 */
393int
394gif_encapcheck6(m, off, proto, arg)
395	const struct mbuf *m;
396	int off;
397	int proto;
398	void *arg;
399{
400	struct ip6_hdr ip6;
401	struct gif_softc *sc;
402	struct ifnet *ifp;
403
404	/* sanity check done in caller */
405	sc = (struct gif_softc *)arg;
406
407	/* LINTED const cast */
408	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
409	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
410
411	return gif_validate6(&ip6, sc, ifp);
412}
413
414int
415in6_gif_attach(sc)
416	struct gif_softc *sc;
417{
418	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
419	    (struct protosw *)&in6_gif_protosw, sc);
420	if (sc->encap_cookie6 == NULL)
421		return EEXIST;
422	return 0;
423}
424
425int
426in6_gif_detach(sc)
427	struct gif_softc *sc;
428{
429	int error;
430
431	error = encap_detach(sc->encap_cookie6);
432	if (error == 0)
433		sc->encap_cookie6 = NULL;
434	return error;
435}
436