in6_gif.c revision 196019 
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: head/sys/netinet6/in6_gif.c 196019 2009-08-01 19:26:27Z rwatson $");
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
49#include <net/if.h>
50#include <net/route.h>
51
52#include <netinet/in.h>
53#include <netinet/in_systm.h>
54#ifdef INET
55#include <netinet/ip.h>
56#endif
57#include <netinet/ip_encap.h>
58#ifdef INET6
59#include <netinet/ip6.h>
60#include <netinet6/ip6_var.h>
61#include <netinet6/in6_gif.h>
62#include <netinet6/in6_var.h>
63#endif
64#include <netinet6/ip6protosw.h>
65#include <netinet/ip_ecn.h>
66#ifdef INET6
67#include <netinet6/ip6_ecn.h>
68#endif
69
70#include <net/if_gif.h>
71
72static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
73			 struct ifnet *);
74
75extern  struct domain inet6domain;
76struct ip6protosw in6_gif_protosw = {
77	.pr_type =	SOCK_RAW,
78	.pr_domain =	&inet6domain,
79	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
80	.pr_flags =	PR_ATOMIC|PR_ADDR,
81	.pr_input =	in6_gif_input,
82	.pr_output =	rip6_output,
83	.pr_ctloutput =	rip6_ctloutput,
84	.pr_usrreqs =	&rip6_usrreqs
85};
86
87int
88in6_gif_output(struct ifnet *ifp,
89    int family,			/* family of the packet to be encapsulate */
90    struct mbuf *m)
91{
92	struct gif_softc *sc = ifp->if_softc;
93	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
94	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
95	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
96	struct ip6_hdr *ip6;
97	struct etherip_header eiphdr;
98	int error, len, proto;
99	u_int8_t itos, otos;
100
101	GIF_LOCK_ASSERT(sc);
102
103	if (sin6_src == NULL || sin6_dst == NULL ||
104	    sin6_src->sin6_family != AF_INET6 ||
105	    sin6_dst->sin6_family != AF_INET6) {
106		m_freem(m);
107		return EAFNOSUPPORT;
108	}
109
110	switch (family) {
111#ifdef INET
112	case AF_INET:
113	    {
114		struct ip *ip;
115
116		proto = IPPROTO_IPV4;
117		if (m->m_len < sizeof(*ip)) {
118			m = m_pullup(m, sizeof(*ip));
119			if (!m)
120				return ENOBUFS;
121		}
122		ip = mtod(m, struct ip *);
123		itos = ip->ip_tos;
124		break;
125	    }
126#endif
127#ifdef INET6
128	case AF_INET6:
129	    {
130		struct ip6_hdr *ip6;
131		proto = IPPROTO_IPV6;
132		if (m->m_len < sizeof(*ip6)) {
133			m = m_pullup(m, sizeof(*ip6));
134			if (!m)
135				return ENOBUFS;
136		}
137		ip6 = mtod(m, struct ip6_hdr *);
138		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139		break;
140	    }
141#endif
142	case AF_LINK:
143		proto = IPPROTO_ETHERIP;
144
145		/*
146		 * GIF_SEND_REVETHIP (disabled by default) intentionally
147		 * sends an EtherIP packet with revered version field in
148		 * the header.  This is a knob for backward compatibility
149		 * with FreeBSD 7.2R or prior.
150		 */
151		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
152			eiphdr.eip_ver = 0;
153			eiphdr.eip_resvl = ETHERIP_VERSION;
154			eiphdr.eip_resvh = 0;
155		} else {
156			eiphdr.eip_ver = ETHERIP_VERSION;
157			eiphdr.eip_resvl = 0;
158			eiphdr.eip_resvh = 0;
159		}
160		/* prepend Ethernet-in-IP header */
161		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
162		if (m && m->m_len < sizeof(struct etherip_header))
163			m = m_pullup(m, sizeof(struct etherip_header));
164		if (m == NULL)
165			return ENOBUFS;
166		bcopy(&eiphdr, mtod(m, struct etherip_header *),
167		    sizeof(struct etherip_header));
168		break;
169
170	default:
171#ifdef DEBUG
172		printf("in6_gif_output: warning: unknown family %d passed\n",
173			family);
174#endif
175		m_freem(m);
176		return EAFNOSUPPORT;
177	}
178
179	/* prepend new IP header */
180	len = sizeof(struct ip6_hdr);
181#ifndef __NO_STRICT_ALIGNMENT
182	if (family == AF_LINK)
183		len += ETHERIP_ALIGN;
184#endif
185	M_PREPEND(m, len, M_DONTWAIT);
186	if (m != NULL && m->m_len < len)
187		m = m_pullup(m, len);
188	if (m == NULL) {
189		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
190		return ENOBUFS;
191	}
192#ifndef __NO_STRICT_ALIGNMENT
193	if (family == AF_LINK) {
194		len = mtod(m, vm_offset_t) & 3;
195		KASSERT(len == 0 || len == ETHERIP_ALIGN,
196		    ("in6_gif_output: unexpected misalignment"));
197		m->m_data += len;
198		m->m_len -= ETHERIP_ALIGN;
199	}
200#endif
201
202	ip6 = mtod(m, struct ip6_hdr *);
203	ip6->ip6_flow	= 0;
204	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
205	ip6->ip6_vfc	|= IPV6_VERSION;
206	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
207	ip6->ip6_nxt	= proto;
208	ip6->ip6_hlim	= V_ip6_gif_hlim;
209	ip6->ip6_src	= sin6_src->sin6_addr;
210	/* bidirectional configured tunnel mode */
211	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
212		ip6->ip6_dst = sin6_dst->sin6_addr;
213	else  {
214		m_freem(m);
215		return ENETUNREACH;
216	}
217	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
218		       &otos, &itos);
219	ip6->ip6_flow &= ~htonl(0xff << 20);
220	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
221
222	if (dst->sin6_family != sin6_dst->sin6_family ||
223	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
224		/* cache route doesn't match */
225		bzero(dst, sizeof(*dst));
226		dst->sin6_family = sin6_dst->sin6_family;
227		dst->sin6_len = sizeof(struct sockaddr_in6);
228		dst->sin6_addr = sin6_dst->sin6_addr;
229		if (sc->gif_ro6.ro_rt) {
230			RTFREE(sc->gif_ro6.ro_rt);
231			sc->gif_ro6.ro_rt = NULL;
232		}
233#if 0
234		GIF2IFP(sc)->if_mtu = GIF_MTU;
235#endif
236	}
237
238	if (sc->gif_ro6.ro_rt == NULL) {
239		rtalloc((struct route *)&sc->gif_ro6);
240		if (sc->gif_ro6.ro_rt == NULL) {
241			m_freem(m);
242			return ENETUNREACH;
243		}
244
245		/* if it constitutes infinite encapsulation, punt. */
246		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
247			m_freem(m);
248			return ENETUNREACH;	/*XXX*/
249		}
250#if 0
251		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
252			- sizeof(struct ip6_hdr);
253#endif
254	}
255
256#ifdef IPV6_MINMTU
257	/*
258	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
259	 * it is too painful to ask for resend of inner packet, to achieve
260	 * path MTU discovery for encapsulated packets.
261	 */
262	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
263#else
264	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
265#endif
266
267	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
268	    sc->gif_ro6.ro_rt != NULL) {
269		RTFREE(sc->gif_ro6.ro_rt);
270		sc->gif_ro6.ro_rt = NULL;
271	}
272
273	return (error);
274}
275
276int
277in6_gif_input(struct mbuf **mp, int *offp, int proto)
278{
279	struct mbuf *m = *mp;
280	struct ifnet *gifp = NULL;
281	struct gif_softc *sc;
282	struct ip6_hdr *ip6;
283	int af = 0;
284	u_int32_t otos;
285
286	ip6 = mtod(m, struct ip6_hdr *);
287
288	sc = (struct gif_softc *)encap_getarg(m);
289	if (sc == NULL) {
290		m_freem(m);
291		V_ip6stat.ip6s_nogif++;
292		return IPPROTO_DONE;
293	}
294
295	gifp = GIF2IFP(sc);
296	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
297		m_freem(m);
298		V_ip6stat.ip6s_nogif++;
299		return IPPROTO_DONE;
300	}
301
302	otos = ip6->ip6_flow;
303	m_adj(m, *offp);
304
305	switch (proto) {
306#ifdef INET
307	case IPPROTO_IPV4:
308	    {
309		struct ip *ip;
310		u_int8_t otos8;
311		af = AF_INET;
312		otos8 = (ntohl(otos) >> 20) & 0xff;
313		if (m->m_len < sizeof(*ip)) {
314			m = m_pullup(m, sizeof(*ip));
315			if (!m)
316				return IPPROTO_DONE;
317		}
318		ip = mtod(m, struct ip *);
319		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
320				  ECN_ALLOWED : ECN_NOCARE,
321				  &otos8, &ip->ip_tos) == 0) {
322			m_freem(m);
323			return IPPROTO_DONE;
324		}
325		break;
326	    }
327#endif /* INET */
328#ifdef INET6
329	case IPPROTO_IPV6:
330	    {
331		struct ip6_hdr *ip6;
332		af = AF_INET6;
333		if (m->m_len < sizeof(*ip6)) {
334			m = m_pullup(m, sizeof(*ip6));
335			if (!m)
336				return IPPROTO_DONE;
337		}
338		ip6 = mtod(m, struct ip6_hdr *);
339		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
340				   ECN_ALLOWED : ECN_NOCARE,
341				   &otos, &ip6->ip6_flow) == 0) {
342			m_freem(m);
343			return IPPROTO_DONE;
344		}
345		break;
346	    }
347#endif
348	case IPPROTO_ETHERIP:
349		af = AF_LINK;
350		break;
351
352	default:
353		V_ip6stat.ip6s_nogif++;
354		m_freem(m);
355		return IPPROTO_DONE;
356	}
357
358	gif_input(m, af, gifp);
359	return IPPROTO_DONE;
360}
361
362/*
363 * validate outer address.
364 */
365static int
366gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
367    struct ifnet *ifp)
368{
369	struct sockaddr_in6 *src, *dst;
370
371	src = (struct sockaddr_in6 *)sc->gif_psrc;
372	dst = (struct sockaddr_in6 *)sc->gif_pdst;
373
374	/*
375	 * Check for address match.  Note that the check is for an incoming
376	 * packet.  We should compare the *source* address in our configuration
377	 * and the *destination* address of the packet, and vice versa.
378	 */
379	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
380	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
381		return 0;
382
383	/* martian filters on outer source - done in ip6_input */
384
385	/* ingress filters on outer source */
386	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
387		struct sockaddr_in6 sin6;
388		struct rtentry *rt;
389
390		bzero(&sin6, sizeof(sin6));
391		sin6.sin6_family = AF_INET6;
392		sin6.sin6_len = sizeof(struct sockaddr_in6);
393		sin6.sin6_addr = ip6->ip6_src;
394		sin6.sin6_scope_id = 0; /* XXX */
395
396		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
397		if (!rt || rt->rt_ifp != ifp) {
398#if 0
399			char ip6buf[INET6_ADDRSTRLEN];
400			log(LOG_WARNING, "%s: packet from %s dropped "
401			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
402			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
403#endif
404			if (rt)
405				RTFREE_LOCKED(rt);
406			return 0;
407		}
408		RTFREE_LOCKED(rt);
409	}
410
411	return 128 * 2;
412}
413
414/*
415 * we know that we are in IFF_UP, outer address available, and outer family
416 * matched the physical addr family.  see gif_encapcheck().
417 * sanity check for arg should have been done in the caller.
418 */
419int
420gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
421{
422	struct ip6_hdr ip6;
423	struct gif_softc *sc;
424	struct ifnet *ifp;
425
426	/* sanity check done in caller */
427	sc = (struct gif_softc *)arg;
428
429	/* LINTED const cast */
430	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
431	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
432
433	return gif_validate6(&ip6, sc, ifp);
434}
435
436int
437in6_gif_attach(struct gif_softc *sc)
438{
439	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
440	    (void *)&in6_gif_protosw, sc);
441	if (sc->encap_cookie6 == NULL)
442		return EEXIST;
443	return 0;
444}
445
446int
447in6_gif_detach(struct gif_softc *sc)
448{
449	int error;
450
451	error = encap_detach(sc->encap_cookie6);
452	if (error == 0)
453		sc->encap_cookie6 = NULL;
454	return error;
455}
456