in6_gif.c revision 171260 
1/*	$FreeBSD: head/sys/netinet6/in6_gif.c 171260 2007-07-05 16:29:40Z delphij $	*/
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
71static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
72			 struct ifnet *);
73
74extern  struct domain inet6domain;
75struct ip6protosw in6_gif_protosw =
76{ SOCK_RAW,	&inet6domain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
77  in6_gif_input, rip6_output,	0,		rip6_ctloutput,
78  0,
79  0,		0,		0,		0,
80  &rip6_usrreqs
81};
82
83int
84in6_gif_output(struct ifnet *ifp,
85    int family,			/* family of the packet to be encapsulate */
86    struct mbuf *m)
87{
88	struct gif_softc *sc = ifp->if_softc;
89	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
90	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
91	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
92	struct ip6_hdr *ip6;
93	struct etherip_header eiphdr;
94	int proto, error;
95	u_int8_t itos, otos;
96
97	GIF_LOCK_ASSERT(sc);
98
99	if (sin6_src == NULL || sin6_dst == NULL ||
100	    sin6_src->sin6_family != AF_INET6 ||
101	    sin6_dst->sin6_family != AF_INET6) {
102		m_freem(m);
103		return EAFNOSUPPORT;
104	}
105
106	switch (family) {
107#ifdef INET
108	case AF_INET:
109	    {
110		struct ip *ip;
111
112		proto = IPPROTO_IPV4;
113		if (m->m_len < sizeof(*ip)) {
114			m = m_pullup(m, sizeof(*ip));
115			if (!m)
116				return ENOBUFS;
117		}
118		ip = mtod(m, struct ip *);
119		itos = ip->ip_tos;
120		break;
121	    }
122#endif
123#ifdef INET6
124	case AF_INET6:
125	    {
126		struct ip6_hdr *ip6;
127		proto = IPPROTO_IPV6;
128		if (m->m_len < sizeof(*ip6)) {
129			m = m_pullup(m, sizeof(*ip6));
130			if (!m)
131				return ENOBUFS;
132		}
133		ip6 = mtod(m, struct ip6_hdr *);
134		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
135		break;
136	    }
137#endif
138	case AF_LINK:
139		proto = IPPROTO_ETHERIP;
140		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
141		eiphdr.eip_pad = 0;
142		/* prepend Ethernet-in-IP header */
143		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
144		if (m && m->m_len < sizeof(struct etherip_header))
145			m = m_pullup(m, sizeof(struct etherip_header));
146		if (m == NULL)
147			return ENOBUFS;
148		bcopy(&eiphdr, mtod(m, struct etherip_header *),
149		    sizeof(struct etherip_header));
150		break;
151
152	default:
153#ifdef DEBUG
154		printf("in6_gif_output: warning: unknown family %d passed\n",
155			family);
156#endif
157		m_freem(m);
158		return EAFNOSUPPORT;
159	}
160
161	/* prepend new IP header */
162	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
163	if (m && m->m_len < sizeof(struct ip6_hdr))
164		m = m_pullup(m, sizeof(struct ip6_hdr));
165	if (m == NULL) {
166		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
167		return ENOBUFS;
168	}
169
170	ip6 = mtod(m, struct ip6_hdr *);
171	ip6->ip6_flow	= 0;
172	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
173	ip6->ip6_vfc	|= IPV6_VERSION;
174	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
175	ip6->ip6_nxt	= proto;
176	ip6->ip6_hlim	= ip6_gif_hlim;
177	ip6->ip6_src	= sin6_src->sin6_addr;
178	/* bidirectional configured tunnel mode */
179	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
180		ip6->ip6_dst = sin6_dst->sin6_addr;
181	else  {
182		m_freem(m);
183		return ENETUNREACH;
184	}
185	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
186		       &otos, &itos);
187	ip6->ip6_flow &= ~htonl(0xff << 20);
188	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
189
190	if (dst->sin6_family != sin6_dst->sin6_family ||
191	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
192		/* cache route doesn't match */
193		bzero(dst, sizeof(*dst));
194		dst->sin6_family = sin6_dst->sin6_family;
195		dst->sin6_len = sizeof(struct sockaddr_in6);
196		dst->sin6_addr = sin6_dst->sin6_addr;
197		if (sc->gif_ro6.ro_rt) {
198			RTFREE(sc->gif_ro6.ro_rt);
199			sc->gif_ro6.ro_rt = NULL;
200		}
201#if 0
202		GIF2IFP(sc)->if_mtu = GIF_MTU;
203#endif
204	}
205
206	if (sc->gif_ro6.ro_rt == NULL) {
207		rtalloc((struct route *)&sc->gif_ro6);
208		if (sc->gif_ro6.ro_rt == NULL) {
209			m_freem(m);
210			return ENETUNREACH;
211		}
212
213		/* if it constitutes infinite encapsulation, punt. */
214		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
215			m_freem(m);
216			return ENETUNREACH;	/*XXX*/
217		}
218#if 0
219		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
220			- sizeof(struct ip6_hdr);
221#endif
222	}
223
224#ifdef IPV6_MINMTU
225	/*
226	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
227	 * it is too painful to ask for resend of inner packet, to achieve
228	 * path MTU discovery for encapsulated packets.
229	 */
230	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
231#else
232	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
233#endif
234
235	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
236	    sc->gif_ro6.ro_rt != NULL) {
237		RTFREE(sc->gif_ro6.ro_rt);
238		sc->gif_ro6.ro_rt = NULL;
239	}
240
241	return (error);
242}
243
244int
245in6_gif_input(struct mbuf **mp, int *offp, int proto)
246{
247	struct mbuf *m = *mp;
248	struct ifnet *gifp = NULL;
249	struct gif_softc *sc;
250	struct ip6_hdr *ip6;
251	int af = 0;
252	u_int32_t otos;
253
254	ip6 = mtod(m, struct ip6_hdr *);
255
256	sc = (struct gif_softc *)encap_getarg(m);
257	if (sc == NULL) {
258		m_freem(m);
259		ip6stat.ip6s_nogif++;
260		return IPPROTO_DONE;
261	}
262
263	gifp = GIF2IFP(sc);
264	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
265		m_freem(m);
266		ip6stat.ip6s_nogif++;
267		return IPPROTO_DONE;
268	}
269
270	otos = ip6->ip6_flow;
271	m_adj(m, *offp);
272
273	switch (proto) {
274#ifdef INET
275	case IPPROTO_IPV4:
276	    {
277		struct ip *ip;
278		u_int8_t otos8;
279		af = AF_INET;
280		otos8 = (ntohl(otos) >> 20) & 0xff;
281		if (m->m_len < sizeof(*ip)) {
282			m = m_pullup(m, sizeof(*ip));
283			if (!m)
284				return IPPROTO_DONE;
285		}
286		ip = mtod(m, struct ip *);
287		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
288				  ECN_ALLOWED : ECN_NOCARE,
289				  &otos8, &ip->ip_tos) == 0) {
290			m_freem(m);
291			return IPPROTO_DONE;
292		}
293		break;
294	    }
295#endif /* INET */
296#ifdef INET6
297	case IPPROTO_IPV6:
298	    {
299		struct ip6_hdr *ip6;
300		af = AF_INET6;
301		if (m->m_len < sizeof(*ip6)) {
302			m = m_pullup(m, sizeof(*ip6));
303			if (!m)
304				return IPPROTO_DONE;
305		}
306		ip6 = mtod(m, struct ip6_hdr *);
307		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
308				   ECN_ALLOWED : ECN_NOCARE,
309				   &otos, &ip6->ip6_flow) == 0) {
310			m_freem(m);
311			return IPPROTO_DONE;
312		}
313		break;
314	    }
315#endif
316	case IPPROTO_ETHERIP:
317		af = AF_LINK;
318		break;
319
320	default:
321		ip6stat.ip6s_nogif++;
322		m_freem(m);
323		return IPPROTO_DONE;
324	}
325
326	gif_input(m, af, gifp);
327	return IPPROTO_DONE;
328}
329
330/*
331 * validate outer address.
332 */
333static int
334gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
335    struct ifnet *ifp)
336{
337	struct sockaddr_in6 *src, *dst;
338
339	src = (struct sockaddr_in6 *)sc->gif_psrc;
340	dst = (struct sockaddr_in6 *)sc->gif_pdst;
341
342	/*
343	 * Check for address match.  Note that the check is for an incoming
344	 * packet.  We should compare the *source* address in our configuration
345	 * and the *destination* address of the packet, and vice versa.
346	 */
347	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
348	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
349		return 0;
350
351	/* martian filters on outer source - done in ip6_input */
352
353	/* ingress filters on outer source */
354	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
355		struct sockaddr_in6 sin6;
356		struct rtentry *rt;
357
358		bzero(&sin6, sizeof(sin6));
359		sin6.sin6_family = AF_INET6;
360		sin6.sin6_len = sizeof(struct sockaddr_in6);
361		sin6.sin6_addr = ip6->ip6_src;
362		sin6.sin6_scope_id = 0; /* XXX */
363
364		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
365		if (!rt || rt->rt_ifp != ifp) {
366#if 0
367			char ip6buf[INET6_ADDRSTRLEN];
368			log(LOG_WARNING, "%s: packet from %s dropped "
369			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
370			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
371#endif
372			if (rt)
373				rtfree(rt);
374			return 0;
375		}
376		rtfree(rt);
377	}
378
379	return 128 * 2;
380}
381
382/*
383 * we know that we are in IFF_UP, outer address available, and outer family
384 * matched the physical addr family.  see gif_encapcheck().
385 * sanity check for arg should have been done in the caller.
386 */
387int
388gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
389{
390	struct ip6_hdr ip6;
391	struct gif_softc *sc;
392	struct ifnet *ifp;
393
394	/* sanity check done in caller */
395	sc = (struct gif_softc *)arg;
396
397	/* LINTED const cast */
398	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
399	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
400
401	return gif_validate6(&ip6, sc, ifp);
402}
403
404int
405in6_gif_attach(struct gif_softc *sc)
406{
407	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
408	    (void *)&in6_gif_protosw, sc);
409	if (sc->encap_cookie6 == NULL)
410		return EEXIST;
411	return 0;
412}
413
414int
415in6_gif_detach(struct gif_softc *sc)
416{
417	int error;
418
419	error = encap_detach(sc->encap_cookie6);
420	if (error == 0)
421		sc->encap_cookie6 = NULL;
422	return error;
423}
424