in_gif.c revision 152242 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 152242 2005-11-09 13:29:16Z ru $	*/
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	.pr_type =		SOCK_RAW,
79	.pr_domain =		&inetdomain,
80	.pr_protocol =		0/* IPPROTO_IPV[46] */,
81	.pr_flags =		PR_ATOMIC|PR_ADDR,
82	.pr_input =		in_gif_input,
83	.pr_output =		(pr_output_t*)rip_output,
84	.pr_ctloutput =		rip_ctloutput,
85	.pr_usrreqs =		&rip_usrreqs
86};
87
88static int ip_gif_ttl = GIF_TTL;
89SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
90	&ip_gif_ttl,	0, "");
91
92int
93in_gif_output(ifp, family, m)
94	struct ifnet	*ifp;
95	int		family;
96	struct mbuf	*m;
97{
98	struct gif_softc *sc = ifp->if_softc;
99	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
100	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
101	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
102	struct ip iphdr;	/* capsule IP header, host byte ordered */
103	int proto, error;
104	u_int8_t tos;
105
106	if (sin_src == NULL || sin_dst == NULL ||
107	    sin_src->sin_family != AF_INET ||
108	    sin_dst->sin_family != AF_INET) {
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		tos = ip->ip_tos;
127		break;
128	    }
129#endif /* INET */
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		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
142		break;
143	    }
144#endif /* INET6 */
145	default:
146#ifdef DEBUG
147		printf("in_gif_output: warning: unknown family %d passed\n",
148			family);
149#endif
150		m_freem(m);
151		return EAFNOSUPPORT;
152	}
153
154	bzero(&iphdr, sizeof(iphdr));
155	iphdr.ip_src = sin_src->sin_addr;
156	/* bidirectional configured tunnel mode */
157	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
158		iphdr.ip_dst = sin_dst->sin_addr;
159	else {
160		m_freem(m);
161		return ENETUNREACH;
162	}
163	iphdr.ip_p = proto;
164	/* version will be set in ip_output() */
165	iphdr.ip_ttl = ip_gif_ttl;
166	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
167	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
168		       &iphdr.ip_tos, &tos);
169
170	/* prepend new IP header */
171	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
172	if (m && m->m_len < sizeof(struct ip))
173		m = m_pullup(m, sizeof(struct ip));
174	if (m == NULL) {
175		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
176		return ENOBUFS;
177	}
178	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
179
180	if (dst->sin_family != sin_dst->sin_family ||
181	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
182		/* cache route doesn't match */
183		bzero(dst, sizeof(*dst));
184		dst->sin_family = sin_dst->sin_family;
185		dst->sin_len = sizeof(struct sockaddr_in);
186		dst->sin_addr = sin_dst->sin_addr;
187		if (sc->gif_ro.ro_rt) {
188			RTFREE(sc->gif_ro.ro_rt);
189			sc->gif_ro.ro_rt = NULL;
190		}
191#if 0
192		GIF2IFP(sc)->if_mtu = GIF_MTU;
193#endif
194	}
195
196	if (sc->gif_ro.ro_rt == NULL) {
197		rtalloc_ign(&sc->gif_ro, 0);
198		if (sc->gif_ro.ro_rt == NULL) {
199			m_freem(m);
200			return ENETUNREACH;
201		}
202
203		/* if it constitutes infinite encapsulation, punt. */
204		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
205			m_freem(m);
206			return ENETUNREACH;	/* XXX */
207		}
208#if 0
209		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
210			- sizeof(struct ip);
211#endif
212	}
213
214	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
215
216	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
217	    sc->gif_ro.ro_rt != NULL) {
218		RTFREE(sc->gif_ro.ro_rt);
219		sc->gif_ro.ro_rt = NULL;
220	}
221
222	return (error);
223}
224
225void
226in_gif_input(m, off)
227	struct mbuf *m;
228	int off;
229{
230	struct ifnet *gifp = NULL;
231	struct gif_softc *sc;
232	struct ip *ip;
233	int af;
234	u_int8_t otos;
235	int proto;
236
237	ip = mtod(m, struct ip *);
238	proto = ip->ip_p;
239
240	sc = (struct gif_softc *)encap_getarg(m);
241	if (sc == NULL) {
242		m_freem(m);
243		ipstat.ips_nogif++;
244		return;
245	}
246
247	gifp = GIF2IFP(sc);
248	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
249		m_freem(m);
250		ipstat.ips_nogif++;
251		return;
252	}
253
254	otos = ip->ip_tos;
255	m_adj(m, off);
256
257	switch (proto) {
258#ifdef INET
259	case IPPROTO_IPV4:
260	    {
261		struct ip *ip;
262		af = AF_INET;
263		if (m->m_len < sizeof(*ip)) {
264			m = m_pullup(m, sizeof(*ip));
265			if (!m)
266				return;
267		}
268		ip = mtod(m, struct ip *);
269		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
270				  ECN_ALLOWED : ECN_NOCARE,
271				  &otos, &ip->ip_tos) == 0) {
272			m_freem(m);
273			return;
274		}
275		break;
276	    }
277#endif
278#ifdef INET6
279	case IPPROTO_IPV6:
280	    {
281		struct ip6_hdr *ip6;
282		u_int8_t itos, oitos;
283
284		af = AF_INET6;
285		if (m->m_len < sizeof(*ip6)) {
286			m = m_pullup(m, sizeof(*ip6));
287			if (!m)
288				return;
289		}
290		ip6 = mtod(m, struct ip6_hdr *);
291		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
292		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
293				  ECN_ALLOWED : ECN_NOCARE,
294				  &otos, &itos) == 0) {
295			m_freem(m);
296			return;
297		}
298		if (itos != oitos) {
299			ip6->ip6_flow &= ~htonl(0xff << 20);
300			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
301		}
302		break;
303	    }
304#endif /* INET6 */
305	default:
306		ipstat.ips_nogif++;
307		m_freem(m);
308		return;
309	}
310	gif_input(m, af, gifp);
311	return;
312}
313
314/*
315 * validate outer address.
316 */
317static int
318gif_validate4(ip, sc, ifp)
319	const struct ip *ip;
320	struct gif_softc *sc;
321	struct ifnet *ifp;
322{
323	struct sockaddr_in *src, *dst;
324	struct in_ifaddr *ia4;
325
326	src = (struct sockaddr_in *)sc->gif_psrc;
327	dst = (struct sockaddr_in *)sc->gif_pdst;
328
329	/* check for address match */
330	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
331	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
332		return 0;
333
334	/* martian filters on outer source - NOT done in ip_input! */
335	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
336		return 0;
337	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
338	case 0: case 127: case 255:
339		return 0;
340	}
341	/* reject packets with broadcast on source */
342	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
343		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
344			continue;
345		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
346			return 0;
347	}
348
349	/* ingress filters on outer source */
350	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
351		struct sockaddr_in sin;
352		struct rtentry *rt;
353
354		bzero(&sin, sizeof(sin));
355		sin.sin_family = AF_INET;
356		sin.sin_len = sizeof(struct sockaddr_in);
357		sin.sin_addr = ip->ip_src;
358		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
359		if (!rt || rt->rt_ifp != ifp) {
360#if 0
361			log(LOG_WARNING, "%s: packet from 0x%x dropped "
362			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
363			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
364#endif
365			if (rt)
366				rtfree(rt);
367			return 0;
368		}
369		rtfree(rt);
370	}
371
372	return 32 * 2;
373}
374
375/*
376 * we know that we are in IFF_UP, outer address available, and outer family
377 * matched the physical addr family.  see gif_encapcheck().
378 */
379int
380gif_encapcheck4(m, off, proto, arg)
381	const struct mbuf *m;
382	int off;
383	int proto;
384	void *arg;
385{
386	struct ip ip;
387	struct gif_softc *sc;
388	struct ifnet *ifp;
389
390	/* sanity check done in caller */
391	sc = (struct gif_softc *)arg;
392
393	/* LINTED const cast */
394	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
395	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
396
397	return gif_validate4(&ip, sc, ifp);
398}
399
400int
401in_gif_attach(sc)
402	struct gif_softc *sc;
403{
404	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
405	    &in_gif_protosw, sc);
406	if (sc->encap_cookie4 == NULL)
407		return EEXIST;
408	return 0;
409}
410
411int
412in_gif_detach(sc)
413	struct gif_softc *sc;
414{
415	int error;
416
417	error = encap_detach(sc->encap_cookie4);
418	if (error == 0)
419		sc->encap_cookie4 = NULL;
420	return error;
421}
422