in_gif.c revision 120891 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 120891 2003-10-07 17:46:18Z ume $	*/
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	if (ifp->if_flags & IFF_LINK1)
165		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
166	else
167		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
168
169	/* prepend new IP header */
170	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
171	if (m && m->m_len < sizeof(struct ip))
172		m = m_pullup(m, sizeof(struct ip));
173	if (m == NULL) {
174		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
175		return ENOBUFS;
176	}
177	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
178
179	if (dst->sin_family != sin_dst->sin_family ||
180	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
181		/* cache route doesn't match */
182		dst->sin_family = sin_dst->sin_family;
183		dst->sin_len = sizeof(struct sockaddr_in);
184		dst->sin_addr = sin_dst->sin_addr;
185		if (sc->gif_ro.ro_rt) {
186			RTFREE(sc->gif_ro.ro_rt);
187			sc->gif_ro.ro_rt = NULL;
188		}
189#if 0
190		sc->gif_if.if_mtu = GIF_MTU;
191#endif
192	}
193
194	if (sc->gif_ro.ro_rt == NULL) {
195		rtalloc(&sc->gif_ro);
196		if (sc->gif_ro.ro_rt == NULL) {
197			m_freem(m);
198			return ENETUNREACH;
199		}
200
201		/* if it constitutes infinite encapsulation, punt. */
202		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
203			m_freem(m);
204			return ENETUNREACH;	/* XXX */
205		}
206#if 0
207		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
208			- sizeof(struct ip);
209#endif
210	}
211
212	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
213	return (error);
214}
215
216void
217in_gif_input(m, off)
218	struct mbuf *m;
219	int off;
220{
221	struct ifnet *gifp = NULL;
222	struct ip *ip;
223	int af;
224	u_int8_t otos;
225	int proto;
226
227	ip = mtod(m, struct ip *);
228	proto = ip->ip_p;
229
230	gifp = (struct ifnet *)encap_getarg(m);
231
232	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
233		m_freem(m);
234		ipstat.ips_nogif++;
235		return;
236	}
237
238	otos = ip->ip_tos;
239	m_adj(m, off);
240
241	switch (proto) {
242#ifdef INET
243	case IPPROTO_IPV4:
244	    {
245		struct ip *ip;
246		af = AF_INET;
247		if (m->m_len < sizeof(*ip)) {
248			m = m_pullup(m, sizeof(*ip));
249			if (!m)
250				return;
251		}
252		ip = mtod(m, struct ip *);
253		if (gifp->if_flags & IFF_LINK1)
254			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
255		else
256			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
257		break;
258	    }
259#endif
260#ifdef INET6
261	case IPPROTO_IPV6:
262	    {
263		struct ip6_hdr *ip6;
264		u_int8_t itos;
265		af = AF_INET6;
266		if (m->m_len < sizeof(*ip6)) {
267			m = m_pullup(m, sizeof(*ip6));
268			if (!m)
269				return;
270		}
271		ip6 = mtod(m, struct ip6_hdr *);
272		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
273		if (gifp->if_flags & IFF_LINK1)
274			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
275		else
276			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
277		ip6->ip6_flow &= ~htonl(0xff << 20);
278		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
279		break;
280	    }
281#endif /* INET6 */
282	default:
283		ipstat.ips_nogif++;
284		m_freem(m);
285		return;
286	}
287	gif_input(m, af, gifp);
288	return;
289}
290
291/*
292 * validate outer address.
293 */
294static int
295gif_validate4(ip, sc, ifp)
296	const struct ip *ip;
297	struct gif_softc *sc;
298	struct ifnet *ifp;
299{
300	struct sockaddr_in *src, *dst;
301	struct in_ifaddr *ia4;
302
303	src = (struct sockaddr_in *)sc->gif_psrc;
304	dst = (struct sockaddr_in *)sc->gif_pdst;
305
306	/* check for address match */
307	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
308	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
309		return 0;
310
311	/* martian filters on outer source - NOT done in ip_input! */
312	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
313		return 0;
314	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
315	case 0: case 127: case 255:
316		return 0;
317	}
318	/* reject packets with broadcast on source */
319	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
320		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
321			continue;
322		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
323			return 0;
324	}
325
326	/* ingress filters on outer source */
327	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
328		struct sockaddr_in sin;
329		struct rtentry *rt;
330
331		bzero(&sin, sizeof(sin));
332		sin.sin_family = AF_INET;
333		sin.sin_len = sizeof(struct sockaddr_in);
334		sin.sin_addr = ip->ip_src;
335		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
336		if (!rt || rt->rt_ifp != ifp) {
337#if 0
338			log(LOG_WARNING, "%s: packet from 0x%x dropped "
339			    "due to ingress filter\n", if_name(&sc->gif_if),
340			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
341#endif
342			if (rt)
343				rtfree(rt);
344			return 0;
345		}
346		rtfree(rt);
347	}
348
349	return 32 * 2;
350}
351
352/*
353 * we know that we are in IFF_UP, outer address available, and outer family
354 * matched the physical addr family.  see gif_encapcheck().
355 */
356int
357gif_encapcheck4(m, off, proto, arg)
358	const struct mbuf *m;
359	int off;
360	int proto;
361	void *arg;
362{
363	struct ip ip;
364	struct gif_softc *sc;
365	struct ifnet *ifp;
366
367	/* sanity check done in caller */
368	sc = (struct gif_softc *)arg;
369
370	/* LINTED const cast */
371	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
372	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
373
374	return gif_validate4(&ip, sc, ifp);
375}
376
377int
378in_gif_attach(sc)
379	struct gif_softc *sc;
380{
381	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
382	    &in_gif_protosw, sc);
383	if (sc->encap_cookie4 == NULL)
384		return EEXIST;
385	return 0;
386}
387
388int
389in_gif_detach(sc)
390	struct gif_softc *sc;
391{
392	int error;
393
394	error = encap_detach(sc->encap_cookie4);
395	if (error == 0)
396		sc->encap_cookie4 = NULL;
397	return error;
398}
399