in6_gif.c revision 9bf362d0cc3f533a0c7e793fd354bfabfce44de6
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
148		/*
149		 * GIF_SEND_REVETHIP (disabled by default) intentionally
150		 * sends an EtherIP packet with revered version field in
151		 * the header.  This is a knob for backward compatibility
152		 * with FreeBSD 7.2R or prior.
153		 */
154		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
155			eiphdr.eip_ver = 0;
156			eiphdr.eip_resvl = ETHERIP_VERSION;
157			eiphdr.eip_resvh = 0;
158		} else {
159			eiphdr.eip_ver = ETHERIP_VERSION;
160			eiphdr.eip_resvl = 0;
161			eiphdr.eip_resvh = 0;
162		}
163		/* prepend Ethernet-in-IP header */
164		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
165		if (m && m->m_len < sizeof(struct etherip_header))
166			m = m_pullup(m, sizeof(struct etherip_header));
167		if (m == NULL)
168			return ENOBUFS;
169		bcopy(&eiphdr, mtod(m, struct etherip_header *),
170		    sizeof(struct etherip_header));
171		break;
172
173	default:
174#ifdef DEBUG
175		printf("in6_gif_output: warning: unknown family %d passed\n",
176			family);
177#endif
178		m_freem(m);
179		return EAFNOSUPPORT;
180	}
181
182	/* prepend new IP header */
183	len = sizeof(struct ip6_hdr);
184#ifndef __NO_STRICT_ALIGNMENT
185	if (family == AF_LINK)
186		len += ETHERIP_ALIGN;
187#endif
188	M_PREPEND(m, len, M_DONTWAIT);
189	if (m != NULL && m->m_len < len)
190		m = m_pullup(m, len);
191	if (m == NULL) {
192		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
193		return ENOBUFS;
194	}
195#ifndef __NO_STRICT_ALIGNMENT
196	if (family == AF_LINK) {
197		len = mtod(m, vm_offset_t) & 3;
198		KASSERT(len == 0 || len == ETHERIP_ALIGN,
199		    ("in6_gif_output: unexpected misalignment"));
200		m->m_data += len;
201		m->m_len -= ETHERIP_ALIGN;
202	}
203#endif
204
205	ip6 = mtod(m, struct ip6_hdr *);
206	ip6->ip6_flow	= 0;
207	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
208	ip6->ip6_vfc	|= IPV6_VERSION;
209	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
210	ip6->ip6_nxt	= proto;
211	ip6->ip6_hlim	= V_ip6_gif_hlim;
212	ip6->ip6_src	= sin6_src->sin6_addr;
213	/* bidirectional configured tunnel mode */
214	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
215		ip6->ip6_dst = sin6_dst->sin6_addr;
216	else  {
217		m_freem(m);
218		return ENETUNREACH;
219	}
220	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
221		       &otos, &itos);
222	ip6->ip6_flow &= ~htonl(0xff << 20);
223	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
224
225	if (dst->sin6_family != sin6_dst->sin6_family ||
226	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
227		/* cache route doesn't match */
228		bzero(dst, sizeof(*dst));
229		dst->sin6_family = sin6_dst->sin6_family;
230		dst->sin6_len = sizeof(struct sockaddr_in6);
231		dst->sin6_addr = sin6_dst->sin6_addr;
232		if (sc->gif_ro6.ro_rt) {
233			RTFREE(sc->gif_ro6.ro_rt);
234			sc->gif_ro6.ro_rt = NULL;
235		}
236#if 0
237		GIF2IFP(sc)->if_mtu = GIF_MTU;
238#endif
239	}
240
241	if (sc->gif_ro6.ro_rt == NULL) {
242		rtalloc((struct route *)&sc->gif_ro6);
243		if (sc->gif_ro6.ro_rt == NULL) {
244			m_freem(m);
245			return ENETUNREACH;
246		}
247
248		/* if it constitutes infinite encapsulation, punt. */
249		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
250			m_freem(m);
251			return ENETUNREACH;	/*XXX*/
252		}
253#if 0
254		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
255			- sizeof(struct ip6_hdr);
256#endif
257	}
258
259#ifdef IPV6_MINMTU
260	/*
261	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
262	 * it is too painful to ask for resend of inner packet, to achieve
263	 * path MTU discovery for encapsulated packets.
264	 */
265	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
266#else
267	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
268#endif
269
270	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
271	    sc->gif_ro6.ro_rt != NULL) {
272		RTFREE(sc->gif_ro6.ro_rt);
273		sc->gif_ro6.ro_rt = NULL;
274	}
275
276	return (error);
277}
278
279int
280in6_gif_input(struct mbuf **mp, int *offp, int proto)
281{
282	INIT_VNET_INET6(curvnet);
283	struct mbuf *m = *mp;
284	struct ifnet *gifp = NULL;
285	struct gif_softc *sc;
286	struct ip6_hdr *ip6;
287	int af = 0;
288	u_int32_t otos;
289
290	ip6 = mtod(m, struct ip6_hdr *);
291
292	sc = (struct gif_softc *)encap_getarg(m);
293	if (sc == NULL) {
294		m_freem(m);
295		V_ip6stat.ip6s_nogif++;
296		return IPPROTO_DONE;
297	}
298
299	gifp = GIF2IFP(sc);
300	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
301		m_freem(m);
302		V_ip6stat.ip6s_nogif++;
303		return IPPROTO_DONE;
304	}
305
306	otos = ip6->ip6_flow;
307	m_adj(m, *offp);
308
309	switch (proto) {
310#ifdef INET
311	case IPPROTO_IPV4:
312	    {
313		struct ip *ip;
314		u_int8_t otos8;
315		af = AF_INET;
316		otos8 = (ntohl(otos) >> 20) & 0xff;
317		if (m->m_len < sizeof(*ip)) {
318			m = m_pullup(m, sizeof(*ip));
319			if (!m)
320				return IPPROTO_DONE;
321		}
322		ip = mtod(m, struct ip *);
323		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
324				  ECN_ALLOWED : ECN_NOCARE,
325				  &otos8, &ip->ip_tos) == 0) {
326			m_freem(m);
327			return IPPROTO_DONE;
328		}
329		break;
330	    }
331#endif /* INET */
332#ifdef INET6
333	case IPPROTO_IPV6:
334	    {
335		struct ip6_hdr *ip6;
336		af = AF_INET6;
337		if (m->m_len < sizeof(*ip6)) {
338			m = m_pullup(m, sizeof(*ip6));
339			if (!m)
340				return IPPROTO_DONE;
341		}
342		ip6 = mtod(m, struct ip6_hdr *);
343		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
344				   ECN_ALLOWED : ECN_NOCARE,
345				   &otos, &ip6->ip6_flow) == 0) {
346			m_freem(m);
347			return IPPROTO_DONE;
348		}
349		break;
350	    }
351#endif
352	case IPPROTO_ETHERIP:
353		af = AF_LINK;
354		break;
355
356	default:
357		V_ip6stat.ip6s_nogif++;
358		m_freem(m);
359		return IPPROTO_DONE;
360	}
361
362	gif_input(m, af, gifp);
363	return IPPROTO_DONE;
364}
365
366/*
367 * validate outer address.
368 */
369static int
370gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
371    struct ifnet *ifp)
372{
373	struct sockaddr_in6 *src, *dst;
374
375	src = (struct sockaddr_in6 *)sc->gif_psrc;
376	dst = (struct sockaddr_in6 *)sc->gif_pdst;
377
378	/*
379	 * Check for address match.  Note that the check is for an incoming
380	 * packet.  We should compare the *source* address in our configuration
381	 * and the *destination* address of the packet, and vice versa.
382	 */
383	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
384	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
385		return 0;
386
387	/* martian filters on outer source - done in ip6_input */
388
389	/* ingress filters on outer source */
390	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
391		struct sockaddr_in6 sin6;
392		struct rtentry *rt;
393
394		bzero(&sin6, sizeof(sin6));
395		sin6.sin6_family = AF_INET6;
396		sin6.sin6_len = sizeof(struct sockaddr_in6);
397		sin6.sin6_addr = ip6->ip6_src;
398		sin6.sin6_scope_id = 0; /* XXX */
399
400		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
401		if (!rt || rt->rt_ifp != ifp) {
402#if 0
403			char ip6buf[INET6_ADDRSTRLEN];
404			log(LOG_WARNING, "%s: packet from %s dropped "
405			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
406			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
407#endif
408			if (rt)
409				RTFREE_LOCKED(rt);
410			return 0;
411		}
412		RTFREE_LOCKED(rt);
413	}
414
415	return 128 * 2;
416}
417
418/*
419 * we know that we are in IFF_UP, outer address available, and outer family
420 * matched the physical addr family.  see gif_encapcheck().
421 * sanity check for arg should have been done in the caller.
422 */
423int
424gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
425{
426	struct ip6_hdr ip6;
427	struct gif_softc *sc;
428	struct ifnet *ifp;
429
430	/* sanity check done in caller */
431	sc = (struct gif_softc *)arg;
432
433	/* LINTED const cast */
434	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
435	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
436
437	return gif_validate6(&ip6, sc, ifp);
438}
439
440int
441in6_gif_attach(struct gif_softc *sc)
442{
443	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
444	    (void *)&in6_gif_protosw, sc);
445	if (sc->encap_cookie6 == NULL)
446		return EEXIST;
447	return 0;
448}
449
450int
451in6_gif_detach(struct gif_softc *sc)
452{
453	int error;
454
455	error = encap_detach(sc->encap_cookie6);
456	if (error == 0)
457		sc->encap_cookie6 = NULL;
458	return error;
459}
460