in_gif.c revision 130662 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 130662 2004-06-18 02:04:07Z bms $	*/
2/*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 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_mrouting.h"
34#include "opt_inet.h"
35#include "opt_inet6.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/socket.h>
40#include <sys/sockio.h>
41#include <sys/mbuf.h>
42#include <sys/errno.h>
43#include <sys/kernel.h>
44#include <sys/sysctl.h>
45#include <sys/protosw.h>
46
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#include <netinet/ip.h>
55#include <netinet/ip_var.h>
56#include <netinet/in_gif.h>
57#include <netinet/in_var.h>
58#include <netinet/ip_encap.h>
59#include <netinet/ip_ecn.h>
60
61#ifdef INET6
62#include <netinet/ip6.h>
63#endif
64
65#ifdef MROUTING
66#include <netinet/ip_mroute.h>
67#endif /* MROUTING */
68
69#include <net/if_gif.h>
70
71#include <net/net_osdep.h>
72
73static int gif_validate4(const struct ip *, struct gif_softc *,
74	struct ifnet *);
75
76extern  struct domain inetdomain;
77struct protosw in_gif_protosw =
78{ SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
79  in_gif_input,	(pr_output_t*)rip_output, 0,	rip_ctloutput,
80  0,
81  0,		0,		0,		0,
82  &rip_usrreqs
83};
84
85static int ip_gif_ttl = GIF_TTL;
86SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
87	&ip_gif_ttl,	0, "");
88
89int
90in_gif_output(ifp, family, m)
91	struct ifnet	*ifp;
92	int		family;
93	struct mbuf	*m;
94{
95	struct gif_softc *sc = (struct gif_softc*)ifp;
96	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
97	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
98	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
99	struct ip iphdr;	/* capsule IP header, host byte ordered */
100	int proto, error;
101	u_int8_t tos;
102
103	if (sin_src == NULL || sin_dst == NULL ||
104	    sin_src->sin_family != AF_INET ||
105	    sin_dst->sin_family != AF_INET) {
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		tos = ip->ip_tos;
124		break;
125	    }
126#endif /* INET */
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		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139		break;
140	    }
141#endif /* INET6 */
142	default:
143#ifdef DEBUG
144		printf("in_gif_output: warning: unknown family %d passed\n",
145			family);
146#endif
147		m_freem(m);
148		return EAFNOSUPPORT;
149	}
150
151	bzero(&iphdr, sizeof(iphdr));
152	iphdr.ip_src = sin_src->sin_addr;
153	/* bidirectional configured tunnel mode */
154	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
155		iphdr.ip_dst = sin_dst->sin_addr;
156	else {
157		m_freem(m);
158		return ENETUNREACH;
159	}
160	iphdr.ip_p = proto;
161	/* version will be set in ip_output() */
162	iphdr.ip_ttl = ip_gif_ttl;
163	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
164	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
165		       &iphdr.ip_tos, &tos);
166
167	/* prepend new IP header */
168	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
169	if (m && m->m_len < sizeof(struct ip))
170		m = m_pullup(m, sizeof(struct ip));
171	if (m == NULL) {
172		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
173		return ENOBUFS;
174	}
175	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
176
177	if (dst->sin_family != sin_dst->sin_family ||
178	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
179		/* cache route doesn't match */
180		bzero(dst, sizeof(*dst));
181		dst->sin_family = sin_dst->sin_family;
182		dst->sin_len = sizeof(struct sockaddr_in);
183		dst->sin_addr = sin_dst->sin_addr;
184		if (sc->gif_ro.ro_rt) {
185			RTFREE(sc->gif_ro.ro_rt);
186			sc->gif_ro.ro_rt = NULL;
187		}
188#if 0
189		sc->gif_if.if_mtu = GIF_MTU;
190#endif
191	}
192
193	if (sc->gif_ro.ro_rt == NULL) {
194		rtalloc_ign(&sc->gif_ro, 0);
195		if (sc->gif_ro.ro_rt == NULL) {
196			m_freem(m);
197			return ENETUNREACH;
198		}
199
200		/* if it constitutes infinite encapsulation, punt. */
201		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
202			m_freem(m);
203			return ENETUNREACH;	/* XXX */
204		}
205#if 0
206		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
207			- sizeof(struct ip);
208#endif
209	}
210
211	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
212	return (error);
213}
214
215void
216in_gif_input(m, off)
217	struct mbuf *m;
218	int off;
219{
220	struct ifnet *gifp = NULL;
221	struct ip *ip;
222	int af;
223	u_int8_t otos;
224	int proto;
225
226	ip = mtod(m, struct ip *);
227	proto = ip->ip_p;
228
229	gifp = (struct ifnet *)encap_getarg(m);
230
231	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
232		m_freem(m);
233		ipstat.ips_nogif++;
234		return;
235	}
236
237	otos = ip->ip_tos;
238	m_adj(m, off);
239
240	switch (proto) {
241#ifdef INET
242	case IPPROTO_IPV4:
243	    {
244		struct ip *ip;
245		af = AF_INET;
246		if (m->m_len < sizeof(*ip)) {
247			m = m_pullup(m, sizeof(*ip));
248			if (!m)
249				return;
250		}
251		ip = mtod(m, struct ip *);
252		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
253				  ECN_ALLOWED : ECN_NOCARE,
254				  &otos, &ip->ip_tos) == 0) {
255			m_freem(m);
256			return;
257		}
258		break;
259	    }
260#endif
261#ifdef INET6
262	case IPPROTO_IPV6:
263	    {
264		struct ip6_hdr *ip6;
265		u_int8_t itos, oitos;
266
267		af = AF_INET6;
268		if (m->m_len < sizeof(*ip6)) {
269			m = m_pullup(m, sizeof(*ip6));
270			if (!m)
271				return;
272		}
273		ip6 = mtod(m, struct ip6_hdr *);
274		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
275		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
276				  ECN_ALLOWED : ECN_NOCARE,
277				  &otos, &itos) == 0) {
278			m_freem(m);
279			return;
280		}
281		if (itos != oitos) {
282			ip6->ip6_flow &= ~htonl(0xff << 20);
283			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
284		}
285		break;
286	    }
287#endif /* INET6 */
288	default:
289		ipstat.ips_nogif++;
290		m_freem(m);
291		return;
292	}
293	gif_input(m, af, gifp);
294	return;
295}
296
297/*
298 * validate outer address.
299 */
300static int
301gif_validate4(ip, sc, ifp)
302	const struct ip *ip;
303	struct gif_softc *sc;
304	struct ifnet *ifp;
305{
306	struct sockaddr_in *src, *dst;
307	struct in_ifaddr *ia4;
308
309	src = (struct sockaddr_in *)sc->gif_psrc;
310	dst = (struct sockaddr_in *)sc->gif_pdst;
311
312	/* check for address match */
313	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
314	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
315		return 0;
316
317	/* martian filters on outer source - NOT done in ip_input! */
318	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
319		return 0;
320	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
321	case 0: case 127: case 255:
322		return 0;
323	}
324	/* reject packets with broadcast on source */
325	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
326		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
327			continue;
328		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
329			return 0;
330	}
331
332	/* ingress filters on outer source */
333	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
334		struct sockaddr_in sin;
335		struct rtentry *rt;
336
337		bzero(&sin, sizeof(sin));
338		sin.sin_family = AF_INET;
339		sin.sin_len = sizeof(struct sockaddr_in);
340		sin.sin_addr = ip->ip_src;
341		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
342		if (!rt || rt->rt_ifp != ifp) {
343#if 0
344			log(LOG_WARNING, "%s: packet from 0x%x dropped "
345			    "due to ingress filter\n", if_name(&sc->gif_if),
346			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
347#endif
348			if (rt)
349				rtfree(rt);
350			return 0;
351		}
352		rtfree(rt);
353	}
354
355	return 32 * 2;
356}
357
358/*
359 * we know that we are in IFF_UP, outer address available, and outer family
360 * matched the physical addr family.  see gif_encapcheck().
361 */
362int
363gif_encapcheck4(m, off, proto, arg)
364	const struct mbuf *m;
365	int off;
366	int proto;
367	void *arg;
368{
369	struct ip ip;
370	struct gif_softc *sc;
371	struct ifnet *ifp;
372
373	/* sanity check done in caller */
374	sc = (struct gif_softc *)arg;
375
376	/* LINTED const cast */
377	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
378	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
379
380	return gif_validate4(&ip, sc, ifp);
381}
382
383int
384in_gif_attach(sc)
385	struct gif_softc *sc;
386{
387	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
388	    &in_gif_protosw, sc);
389	if (sc->encap_cookie4 == NULL)
390		return EEXIST;
391	return 0;
392}
393
394int
395in_gif_detach(sc)
396	struct gif_softc *sc;
397{
398	int error;
399
400	error = encap_detach(sc->encap_cookie4);
401	if (error == 0)
402		sc->encap_cookie4 = NULL;
403	return error;
404}
405