in6_gif.c revision 0d684d927bf42ec9c53b0f921e6aaa42e7236cd7
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
48#include <sys/malloc.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#endif
70
71#include <net/if_gif.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(struct ifnet *ifp,
87    int family,			/* family of the packet to be encapsulate */
88    struct mbuf *m)
89{
90	struct gif_softc *sc = ifp->if_softc;
91	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
92	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
93	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
94	struct ip6_hdr *ip6;
95	struct etherip_header eiphdr;
96	int proto, error;
97	u_int8_t itos, otos;
98
99	GIF_LOCK_ASSERT(sc);
100
101	if (sin6_src == NULL || sin6_dst == NULL ||
102	    sin6_src->sin6_family != AF_INET6 ||
103	    sin6_dst->sin6_family != AF_INET6) {
104		m_freem(m);
105		return EAFNOSUPPORT;
106	}
107
108	switch (family) {
109#ifdef INET
110	case AF_INET:
111	    {
112		struct ip *ip;
113
114		proto = IPPROTO_IPV4;
115		if (m->m_len < sizeof(*ip)) {
116			m = m_pullup(m, sizeof(*ip));
117			if (!m)
118				return ENOBUFS;
119		}
120		ip = mtod(m, struct ip *);
121		itos = ip->ip_tos;
122		break;
123	    }
124#endif
125#ifdef INET6
126	case AF_INET6:
127	    {
128		struct ip6_hdr *ip6;
129		proto = IPPROTO_IPV6;
130		if (m->m_len < sizeof(*ip6)) {
131			m = m_pullup(m, sizeof(*ip6));
132			if (!m)
133				return ENOBUFS;
134		}
135		ip6 = mtod(m, struct ip6_hdr *);
136		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
137		break;
138	    }
139#endif
140	case AF_LINK:
141		proto = IPPROTO_ETHERIP;
142		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
143		eiphdr.eip_pad = 0;
144		/* prepend Ethernet-in-IP header */
145		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
146		if (m && m->m_len < sizeof(struct etherip_header))
147			m = m_pullup(m, sizeof(struct etherip_header));
148		if (m == NULL)
149			return ENOBUFS;
150		bcopy(&eiphdr, mtod(m, struct etherip_header *),
151		    sizeof(struct etherip_header));
152		break;
153
154	default:
155#ifdef DEBUG
156		printf("in6_gif_output: warning: unknown family %d passed\n",
157			family);
158#endif
159		m_freem(m);
160		return EAFNOSUPPORT;
161	}
162
163	/* prepend new IP header */
164	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
165	if (m && m->m_len < sizeof(struct ip6_hdr))
166		m = m_pullup(m, sizeof(struct ip6_hdr));
167	if (m == NULL) {
168		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
169		return ENOBUFS;
170	}
171
172	ip6 = mtod(m, struct ip6_hdr *);
173	ip6->ip6_flow	= 0;
174	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
175	ip6->ip6_vfc	|= IPV6_VERSION;
176	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
177	ip6->ip6_nxt	= proto;
178	ip6->ip6_hlim	= ip6_gif_hlim;
179	ip6->ip6_src	= sin6_src->sin6_addr;
180	/* bidirectional configured tunnel mode */
181	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
182		ip6->ip6_dst = sin6_dst->sin6_addr;
183	else  {
184		m_freem(m);
185		return ENETUNREACH;
186	}
187	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
188		       &otos, &itos);
189	ip6->ip6_flow &= ~htonl(0xff << 20);
190	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
191
192	if (dst->sin6_family != sin6_dst->sin6_family ||
193	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
194		/* cache route doesn't match */
195		bzero(dst, sizeof(*dst));
196		dst->sin6_family = sin6_dst->sin6_family;
197		dst->sin6_len = sizeof(struct sockaddr_in6);
198		dst->sin6_addr = sin6_dst->sin6_addr;
199		if (sc->gif_ro6.ro_rt) {
200			RTFREE(sc->gif_ro6.ro_rt);
201			sc->gif_ro6.ro_rt = NULL;
202		}
203#if 0
204		GIF2IFP(sc)->if_mtu = GIF_MTU;
205#endif
206	}
207
208	if (sc->gif_ro6.ro_rt == NULL) {
209		rtalloc((struct route *)&sc->gif_ro6);
210		if (sc->gif_ro6.ro_rt == NULL) {
211			m_freem(m);
212			return ENETUNREACH;
213		}
214
215		/* if it constitutes infinite encapsulation, punt. */
216		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
217			m_freem(m);
218			return ENETUNREACH;	/*XXX*/
219		}
220#if 0
221		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
222			- sizeof(struct ip6_hdr);
223#endif
224	}
225
226#ifdef IPV6_MINMTU
227	/*
228	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
229	 * it is too painful to ask for resend of inner packet, to achieve
230	 * path MTU discovery for encapsulated packets.
231	 */
232	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
233#else
234	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
235#endif
236
237	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
238	    sc->gif_ro6.ro_rt != NULL) {
239		RTFREE(sc->gif_ro6.ro_rt);
240		sc->gif_ro6.ro_rt = NULL;
241	}
242
243	return (error);
244}
245
246int
247in6_gif_input(struct mbuf **mp, int *offp, int proto)
248{
249	struct mbuf *m = *mp;
250	struct ifnet *gifp = NULL;
251	struct gif_softc *sc;
252	struct ip6_hdr *ip6;
253	int af = 0;
254	u_int32_t otos;
255
256	ip6 = mtod(m, struct ip6_hdr *);
257
258	sc = (struct gif_softc *)encap_getarg(m);
259	if (sc == NULL) {
260		m_freem(m);
261		ip6stat.ip6s_nogif++;
262		return IPPROTO_DONE;
263	}
264
265	gifp = GIF2IFP(sc);
266	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
267		m_freem(m);
268		ip6stat.ip6s_nogif++;
269		return IPPROTO_DONE;
270	}
271
272	otos = ip6->ip6_flow;
273	m_adj(m, *offp);
274
275	switch (proto) {
276#ifdef INET
277	case IPPROTO_IPV4:
278	    {
279		struct ip *ip;
280		u_int8_t otos8;
281		af = AF_INET;
282		otos8 = (ntohl(otos) >> 20) & 0xff;
283		if (m->m_len < sizeof(*ip)) {
284			m = m_pullup(m, sizeof(*ip));
285			if (!m)
286				return IPPROTO_DONE;
287		}
288		ip = mtod(m, struct ip *);
289		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
290				  ECN_ALLOWED : ECN_NOCARE,
291				  &otos8, &ip->ip_tos) == 0) {
292			m_freem(m);
293			return IPPROTO_DONE;
294		}
295		break;
296	    }
297#endif /* INET */
298#ifdef INET6
299	case IPPROTO_IPV6:
300	    {
301		struct ip6_hdr *ip6;
302		af = AF_INET6;
303		if (m->m_len < sizeof(*ip6)) {
304			m = m_pullup(m, sizeof(*ip6));
305			if (!m)
306				return IPPROTO_DONE;
307		}
308		ip6 = mtod(m, struct ip6_hdr *);
309		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
310				   ECN_ALLOWED : ECN_NOCARE,
311				   &otos, &ip6->ip6_flow) == 0) {
312			m_freem(m);
313			return IPPROTO_DONE;
314		}
315		break;
316	    }
317#endif
318	case IPPROTO_ETHERIP:
319		af = AF_LINK;
320		break;
321
322	default:
323		ip6stat.ip6s_nogif++;
324		m_freem(m);
325		return IPPROTO_DONE;
326	}
327
328	gif_input(m, af, gifp);
329	return IPPROTO_DONE;
330}
331
332/*
333 * validate outer address.
334 */
335static int
336gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
337    struct ifnet *ifp)
338{
339	struct sockaddr_in6 *src, *dst;
340
341	src = (struct sockaddr_in6 *)sc->gif_psrc;
342	dst = (struct sockaddr_in6 *)sc->gif_pdst;
343
344	/*
345	 * Check for address match.  Note that the check is for an incoming
346	 * packet.  We should compare the *source* address in our configuration
347	 * and the *destination* address of the packet, and vice versa.
348	 */
349	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
350	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
351		return 0;
352
353	/* martian filters on outer source - done in ip6_input */
354
355	/* ingress filters on outer source */
356	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
357		struct sockaddr_in6 sin6;
358		struct rtentry *rt;
359
360		bzero(&sin6, sizeof(sin6));
361		sin6.sin6_family = AF_INET6;
362		sin6.sin6_len = sizeof(struct sockaddr_in6);
363		sin6.sin6_addr = ip6->ip6_src;
364		sin6.sin6_scope_id = 0; /* XXX */
365
366		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
367		if (!rt || rt->rt_ifp != ifp) {
368#if 0
369			char ip6buf[INET6_ADDRSTRLEN];
370			log(LOG_WARNING, "%s: packet from %s dropped "
371			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
372			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
373#endif
374			if (rt)
375				rtfree(rt);
376			return 0;
377		}
378		rtfree(rt);
379	}
380
381	return 128 * 2;
382}
383
384/*
385 * we know that we are in IFF_UP, outer address available, and outer family
386 * matched the physical addr family.  see gif_encapcheck().
387 * sanity check for arg should have been done in the caller.
388 */
389int
390gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
391{
392	struct ip6_hdr ip6;
393	struct gif_softc *sc;
394	struct ifnet *ifp;
395
396	/* sanity check done in caller */
397	sc = (struct gif_softc *)arg;
398
399	/* LINTED const cast */
400	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
401	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
402
403	return gif_validate6(&ip6, sc, ifp);
404}
405
406int
407in6_gif_attach(struct gif_softc *sc)
408{
409	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
410	    (void *)&in6_gif_protosw, sc);
411	if (sc->encap_cookie6 == NULL)
412		return EEXIST;
413	return 0;
414}
415
416int
417in6_gif_detach(struct gif_softc *sc)
418{
419	int error;
420
421	error = encap_detach(sc->encap_cookie6);
422	if (error == 0)
423		sc->encap_cookie6 = NULL;
424	return error;
425}
426