in6_gif.c revision 74f63d4ce14b7d970f6fe45d8d855faaaf5f7ed5
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 error, len, proto;
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	len = sizeof(struct ip6_hdr);
170#ifndef __NO_STRICT_ALIGNMENT
171	if (family == AF_LINK)
172		len += ETHERIP_ALIGN;
173#endif
174	M_PREPEND(m, len, M_DONTWAIT);
175	if (m != NULL && m->m_len < len)
176		m = m_pullup(m, len);
177	if (m == NULL) {
178		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
179		return ENOBUFS;
180	}
181#ifndef __NO_STRICT_ALIGNMENT
182	if (family == AF_LINK) {
183		len = mtod(m, vm_offset_t) & 3;
184		KASSERT(len == 0 || len == ETHERIP_ALIGN,
185		    ("in6_gif_output: unexpected misalignment"));
186		m->m_data += len;
187		m->m_len -= ETHERIP_ALIGN;
188	}
189#endif
190
191	ip6 = mtod(m, struct ip6_hdr *);
192	ip6->ip6_flow	= 0;
193	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
194	ip6->ip6_vfc	|= IPV6_VERSION;
195	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
196	ip6->ip6_nxt	= proto;
197	ip6->ip6_hlim	= V_ip6_gif_hlim;
198	ip6->ip6_src	= sin6_src->sin6_addr;
199	/* bidirectional configured tunnel mode */
200	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
201		ip6->ip6_dst = sin6_dst->sin6_addr;
202	else  {
203		m_freem(m);
204		return ENETUNREACH;
205	}
206	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
207		       &otos, &itos);
208	ip6->ip6_flow &= ~htonl(0xff << 20);
209	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
210
211	if (dst->sin6_family != sin6_dst->sin6_family ||
212	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
213		/* cache route doesn't match */
214		bzero(dst, sizeof(*dst));
215		dst->sin6_family = sin6_dst->sin6_family;
216		dst->sin6_len = sizeof(struct sockaddr_in6);
217		dst->sin6_addr = sin6_dst->sin6_addr;
218		if (sc->gif_ro6.ro_rt) {
219			RTFREE(sc->gif_ro6.ro_rt);
220			sc->gif_ro6.ro_rt = NULL;
221		}
222#if 0
223		GIF2IFP(sc)->if_mtu = GIF_MTU;
224#endif
225	}
226
227	if (sc->gif_ro6.ro_rt == NULL) {
228		rtalloc((struct route *)&sc->gif_ro6);
229		if (sc->gif_ro6.ro_rt == NULL) {
230			m_freem(m);
231			return ENETUNREACH;
232		}
233
234		/* if it constitutes infinite encapsulation, punt. */
235		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
236			m_freem(m);
237			return ENETUNREACH;	/*XXX*/
238		}
239#if 0
240		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
241			- sizeof(struct ip6_hdr);
242#endif
243	}
244
245#ifdef IPV6_MINMTU
246	/*
247	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
248	 * it is too painful to ask for resend of inner packet, to achieve
249	 * path MTU discovery for encapsulated packets.
250	 */
251	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
252#else
253	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
254#endif
255
256	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
257	    sc->gif_ro6.ro_rt != NULL) {
258		RTFREE(sc->gif_ro6.ro_rt);
259		sc->gif_ro6.ro_rt = NULL;
260	}
261
262	return (error);
263}
264
265int
266in6_gif_input(struct mbuf **mp, int *offp, int proto)
267{
268	INIT_VNET_INET6(curvnet);
269	struct mbuf *m = *mp;
270	struct ifnet *gifp = NULL;
271	struct gif_softc *sc;
272	struct ip6_hdr *ip6;
273	int af = 0;
274	u_int32_t otos;
275
276	ip6 = mtod(m, struct ip6_hdr *);
277
278	sc = (struct gif_softc *)encap_getarg(m);
279	if (sc == NULL) {
280		m_freem(m);
281		V_ip6stat.ip6s_nogif++;
282		return IPPROTO_DONE;
283	}
284
285	gifp = GIF2IFP(sc);
286	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
287		m_freem(m);
288		V_ip6stat.ip6s_nogif++;
289		return IPPROTO_DONE;
290	}
291
292	otos = ip6->ip6_flow;
293	m_adj(m, *offp);
294
295	switch (proto) {
296#ifdef INET
297	case IPPROTO_IPV4:
298	    {
299		struct ip *ip;
300		u_int8_t otos8;
301		af = AF_INET;
302		otos8 = (ntohl(otos) >> 20) & 0xff;
303		if (m->m_len < sizeof(*ip)) {
304			m = m_pullup(m, sizeof(*ip));
305			if (!m)
306				return IPPROTO_DONE;
307		}
308		ip = mtod(m, struct ip *);
309		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
310				  ECN_ALLOWED : ECN_NOCARE,
311				  &otos8, &ip->ip_tos) == 0) {
312			m_freem(m);
313			return IPPROTO_DONE;
314		}
315		break;
316	    }
317#endif /* INET */
318#ifdef INET6
319	case IPPROTO_IPV6:
320	    {
321		struct ip6_hdr *ip6;
322		af = AF_INET6;
323		if (m->m_len < sizeof(*ip6)) {
324			m = m_pullup(m, sizeof(*ip6));
325			if (!m)
326				return IPPROTO_DONE;
327		}
328		ip6 = mtod(m, struct ip6_hdr *);
329		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
330				   ECN_ALLOWED : ECN_NOCARE,
331				   &otos, &ip6->ip6_flow) == 0) {
332			m_freem(m);
333			return IPPROTO_DONE;
334		}
335		break;
336	    }
337#endif
338	case IPPROTO_ETHERIP:
339		af = AF_LINK;
340		break;
341
342	default:
343		V_ip6stat.ip6s_nogif++;
344		m_freem(m);
345		return IPPROTO_DONE;
346	}
347
348	gif_input(m, af, gifp);
349	return IPPROTO_DONE;
350}
351
352/*
353 * validate outer address.
354 */
355static int
356gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
357    struct ifnet *ifp)
358{
359	struct sockaddr_in6 *src, *dst;
360
361	src = (struct sockaddr_in6 *)sc->gif_psrc;
362	dst = (struct sockaddr_in6 *)sc->gif_pdst;
363
364	/*
365	 * Check for address match.  Note that the check is for an incoming
366	 * packet.  We should compare the *source* address in our configuration
367	 * and the *destination* address of the packet, and vice versa.
368	 */
369	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
370	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
371		return 0;
372
373	/* martian filters on outer source - done in ip6_input */
374
375	/* ingress filters on outer source */
376	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
377		struct sockaddr_in6 sin6;
378		struct rtentry *rt;
379
380		bzero(&sin6, sizeof(sin6));
381		sin6.sin6_family = AF_INET6;
382		sin6.sin6_len = sizeof(struct sockaddr_in6);
383		sin6.sin6_addr = ip6->ip6_src;
384		sin6.sin6_scope_id = 0; /* XXX */
385
386		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
387		if (!rt || rt->rt_ifp != ifp) {
388#if 0
389			char ip6buf[INET6_ADDRSTRLEN];
390			log(LOG_WARNING, "%s: packet from %s dropped "
391			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
392			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
393#endif
394			if (rt)
395				RTFREE_LOCKED(rt);
396			return 0;
397		}
398		RTFREE_LOCKED(rt);
399	}
400
401	return 128 * 2;
402}
403
404/*
405 * we know that we are in IFF_UP, outer address available, and outer family
406 * matched the physical addr family.  see gif_encapcheck().
407 * sanity check for arg should have been done in the caller.
408 */
409int
410gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
411{
412	struct ip6_hdr ip6;
413	struct gif_softc *sc;
414	struct ifnet *ifp;
415
416	/* sanity check done in caller */
417	sc = (struct gif_softc *)arg;
418
419	/* LINTED const cast */
420	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
421	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
422
423	return gif_validate6(&ip6, sc, ifp);
424}
425
426int
427in6_gif_attach(struct gif_softc *sc)
428{
429	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
430	    (void *)&in6_gif_protosw, sc);
431	if (sc->encap_cookie6 == NULL)
432		return EEXIST;
433	return 0;
434}
435
436int
437in6_gif_detach(struct gif_softc *sc)
438{
439	int error;
440
441	error = encap_detach(sc->encap_cookie6);
442	if (error == 0)
443		sc->encap_cookie6 = NULL;
444	return error;
445}
446