in_gif.c revision 138653 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 138653 2004-12-10 07:51:14Z glebius $	*/
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
213	if (!(sc->gif_if.if_flags & IFF_LINK0) &&
214	    sc->gif_ro.ro_rt != NULL) {
215		RTFREE(sc->gif_ro.ro_rt);
216		sc->gif_ro.ro_rt = NULL;
217	}
218
219	return (error);
220}
221
222void
223in_gif_input(m, off)
224	struct mbuf *m;
225	int off;
226{
227	struct ifnet *gifp = NULL;
228	struct ip *ip;
229	int af;
230	u_int8_t otos;
231	int proto;
232
233	ip = mtod(m, struct ip *);
234	proto = ip->ip_p;
235
236	gifp = (struct ifnet *)encap_getarg(m);
237
238	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
239		m_freem(m);
240		ipstat.ips_nogif++;
241		return;
242	}
243
244	otos = ip->ip_tos;
245	m_adj(m, off);
246
247	switch (proto) {
248#ifdef INET
249	case IPPROTO_IPV4:
250	    {
251		struct ip *ip;
252		af = AF_INET;
253		if (m->m_len < sizeof(*ip)) {
254			m = m_pullup(m, sizeof(*ip));
255			if (!m)
256				return;
257		}
258		ip = mtod(m, struct ip *);
259		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
260				  ECN_ALLOWED : ECN_NOCARE,
261				  &otos, &ip->ip_tos) == 0) {
262			m_freem(m);
263			return;
264		}
265		break;
266	    }
267#endif
268#ifdef INET6
269	case IPPROTO_IPV6:
270	    {
271		struct ip6_hdr *ip6;
272		u_int8_t itos, oitos;
273
274		af = AF_INET6;
275		if (m->m_len < sizeof(*ip6)) {
276			m = m_pullup(m, sizeof(*ip6));
277			if (!m)
278				return;
279		}
280		ip6 = mtod(m, struct ip6_hdr *);
281		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
282		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
283				  ECN_ALLOWED : ECN_NOCARE,
284				  &otos, &itos) == 0) {
285			m_freem(m);
286			return;
287		}
288		if (itos != oitos) {
289			ip6->ip6_flow &= ~htonl(0xff << 20);
290			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
291		}
292		break;
293	    }
294#endif /* INET6 */
295	default:
296		ipstat.ips_nogif++;
297		m_freem(m);
298		return;
299	}
300	gif_input(m, af, gifp);
301	return;
302}
303
304/*
305 * validate outer address.
306 */
307static int
308gif_validate4(ip, sc, ifp)
309	const struct ip *ip;
310	struct gif_softc *sc;
311	struct ifnet *ifp;
312{
313	struct sockaddr_in *src, *dst;
314	struct in_ifaddr *ia4;
315
316	src = (struct sockaddr_in *)sc->gif_psrc;
317	dst = (struct sockaddr_in *)sc->gif_pdst;
318
319	/* check for address match */
320	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
321	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
322		return 0;
323
324	/* martian filters on outer source - NOT done in ip_input! */
325	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
326		return 0;
327	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
328	case 0: case 127: case 255:
329		return 0;
330	}
331	/* reject packets with broadcast on source */
332	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
333		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
334			continue;
335		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
336			return 0;
337	}
338
339	/* ingress filters on outer source */
340	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
341		struct sockaddr_in sin;
342		struct rtentry *rt;
343
344		bzero(&sin, sizeof(sin));
345		sin.sin_family = AF_INET;
346		sin.sin_len = sizeof(struct sockaddr_in);
347		sin.sin_addr = ip->ip_src;
348		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
349		if (!rt || rt->rt_ifp != ifp) {
350#if 0
351			log(LOG_WARNING, "%s: packet from 0x%x dropped "
352			    "due to ingress filter\n", if_name(&sc->gif_if),
353			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
354#endif
355			if (rt)
356				rtfree(rt);
357			return 0;
358		}
359		rtfree(rt);
360	}
361
362	return 32 * 2;
363}
364
365/*
366 * we know that we are in IFF_UP, outer address available, and outer family
367 * matched the physical addr family.  see gif_encapcheck().
368 */
369int
370gif_encapcheck4(m, off, proto, arg)
371	const struct mbuf *m;
372	int off;
373	int proto;
374	void *arg;
375{
376	struct ip ip;
377	struct gif_softc *sc;
378	struct ifnet *ifp;
379
380	/* sanity check done in caller */
381	sc = (struct gif_softc *)arg;
382
383	/* LINTED const cast */
384	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
385	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
386
387	return gif_validate4(&ip, sc, ifp);
388}
389
390int
391in_gif_attach(sc)
392	struct gif_softc *sc;
393{
394	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
395	    &in_gif_protosw, sc);
396	if (sc->encap_cookie4 == NULL)
397		return EEXIST;
398	return 0;
399}
400
401int
402in_gif_detach(sc)
403	struct gif_softc *sc;
404{
405	int error;
406
407	error = encap_detach(sc->encap_cookie4);
408	if (error == 0)
409		sc->encap_cookie4 = NULL;
410	return error;
411}
412