in_gif.c revision 153621 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 153621 2005-12-21 21:29:45Z thompsa $	*/
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	struct etherip_header eiphdr;
104	int proto, error;
105	u_int8_t tos;
106
107	if (sin_src == NULL || sin_dst == NULL ||
108	    sin_src->sin_family != AF_INET ||
109	    sin_dst->sin_family != AF_INET) {
110		m_freem(m);
111		return EAFNOSUPPORT;
112	}
113
114	switch (family) {
115#ifdef INET
116	case AF_INET:
117	    {
118		struct ip *ip;
119
120		proto = IPPROTO_IPV4;
121		if (m->m_len < sizeof(*ip)) {
122			m = m_pullup(m, sizeof(*ip));
123			if (!m)
124				return ENOBUFS;
125		}
126		ip = mtod(m, struct ip *);
127		tos = ip->ip_tos;
128		break;
129	    }
130#endif /* INET */
131#ifdef INET6
132	case AF_INET6:
133	    {
134		struct ip6_hdr *ip6;
135		proto = IPPROTO_IPV6;
136		if (m->m_len < sizeof(*ip6)) {
137			m = m_pullup(m, sizeof(*ip6));
138			if (!m)
139				return ENOBUFS;
140		}
141		ip6 = mtod(m, struct ip6_hdr *);
142		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
143		break;
144	    }
145#endif /* INET6 */
146	case AF_LINK:
147 		proto = IPPROTO_ETHERIP;
148 		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
149 		eiphdr.eip_pad = 0;
150 		/* prepend Ethernet-in-IP header */
151 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
152 		if (m && m->m_len < sizeof(struct etherip_header))
153 			m = m_pullup(m, sizeof(struct etherip_header));
154 		if (m == NULL)
155 			return ENOBUFS;
156 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
157		    sizeof(struct etherip_header));
158		break;
159
160	default:
161#ifdef DEBUG
162		printf("in_gif_output: warning: unknown family %d passed\n",
163			family);
164#endif
165		m_freem(m);
166		return EAFNOSUPPORT;
167	}
168
169	bzero(&iphdr, sizeof(iphdr));
170	iphdr.ip_src = sin_src->sin_addr;
171	/* bidirectional configured tunnel mode */
172	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
173		iphdr.ip_dst = sin_dst->sin_addr;
174	else {
175		m_freem(m);
176		return ENETUNREACH;
177	}
178	iphdr.ip_p = proto;
179	/* version will be set in ip_output() */
180	iphdr.ip_ttl = ip_gif_ttl;
181	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
182	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
183		       &iphdr.ip_tos, &tos);
184
185	/* prepend new IP header */
186	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
187	if (m && m->m_len < sizeof(struct ip))
188		m = m_pullup(m, sizeof(struct ip));
189	if (m == NULL) {
190		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
191		return ENOBUFS;
192	}
193	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
194
195	if (dst->sin_family != sin_dst->sin_family ||
196	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
197		/* cache route doesn't match */
198		bzero(dst, sizeof(*dst));
199		dst->sin_family = sin_dst->sin_family;
200		dst->sin_len = sizeof(struct sockaddr_in);
201		dst->sin_addr = sin_dst->sin_addr;
202		if (sc->gif_ro.ro_rt) {
203			RTFREE(sc->gif_ro.ro_rt);
204			sc->gif_ro.ro_rt = NULL;
205		}
206#if 0
207		GIF2IFP(sc)->if_mtu = GIF_MTU;
208#endif
209	}
210
211	if (sc->gif_ro.ro_rt == NULL) {
212		rtalloc_ign(&sc->gif_ro, 0);
213		if (sc->gif_ro.ro_rt == NULL) {
214			m_freem(m);
215			return ENETUNREACH;
216		}
217
218		/* if it constitutes infinite encapsulation, punt. */
219		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
220			m_freem(m);
221			return ENETUNREACH;	/* XXX */
222		}
223#if 0
224		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
225			- sizeof(struct ip);
226#endif
227	}
228
229	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
230
231	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
232	    sc->gif_ro.ro_rt != NULL) {
233		RTFREE(sc->gif_ro.ro_rt);
234		sc->gif_ro.ro_rt = NULL;
235	}
236
237	return (error);
238}
239
240void
241in_gif_input(m, off)
242	struct mbuf *m;
243	int off;
244{
245	struct ifnet *gifp = NULL;
246	struct gif_softc *sc;
247	struct ip *ip;
248	int af;
249	u_int8_t otos;
250	int proto;
251
252	ip = mtod(m, struct ip *);
253	proto = ip->ip_p;
254
255	sc = (struct gif_softc *)encap_getarg(m);
256	if (sc == NULL) {
257		m_freem(m);
258		ipstat.ips_nogif++;
259		return;
260	}
261
262	gifp = GIF2IFP(sc);
263	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
264		m_freem(m);
265		ipstat.ips_nogif++;
266		return;
267	}
268
269	otos = ip->ip_tos;
270	m_adj(m, off);
271
272	switch (proto) {
273#ifdef INET
274	case IPPROTO_IPV4:
275	    {
276		struct ip *ip;
277		af = AF_INET;
278		if (m->m_len < sizeof(*ip)) {
279			m = m_pullup(m, sizeof(*ip));
280			if (!m)
281				return;
282		}
283		ip = mtod(m, struct ip *);
284		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
285				  ECN_ALLOWED : ECN_NOCARE,
286				  &otos, &ip->ip_tos) == 0) {
287			m_freem(m);
288			return;
289		}
290		break;
291	    }
292#endif
293#ifdef INET6
294	case IPPROTO_IPV6:
295	    {
296		struct ip6_hdr *ip6;
297		u_int8_t itos, oitos;
298
299		af = AF_INET6;
300		if (m->m_len < sizeof(*ip6)) {
301			m = m_pullup(m, sizeof(*ip6));
302			if (!m)
303				return;
304		}
305		ip6 = mtod(m, struct ip6_hdr *);
306		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
307		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
308				  ECN_ALLOWED : ECN_NOCARE,
309				  &otos, &itos) == 0) {
310			m_freem(m);
311			return;
312		}
313		if (itos != oitos) {
314			ip6->ip6_flow &= ~htonl(0xff << 20);
315			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
316		}
317		break;
318	    }
319#endif /* INET6 */
320 	case IPPROTO_ETHERIP:
321 		af = AF_LINK;
322 		break;
323
324	default:
325		ipstat.ips_nogif++;
326		m_freem(m);
327		return;
328	}
329	gif_input(m, af, gifp);
330	return;
331}
332
333/*
334 * validate outer address.
335 */
336static int
337gif_validate4(ip, sc, ifp)
338	const struct ip *ip;
339	struct gif_softc *sc;
340	struct ifnet *ifp;
341{
342	struct sockaddr_in *src, *dst;
343	struct in_ifaddr *ia4;
344
345	src = (struct sockaddr_in *)sc->gif_psrc;
346	dst = (struct sockaddr_in *)sc->gif_pdst;
347
348	/* check for address match */
349	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
350	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
351		return 0;
352
353	/* martian filters on outer source - NOT done in ip_input! */
354	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
355		return 0;
356	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
357	case 0: case 127: case 255:
358		return 0;
359	}
360	/* reject packets with broadcast on source */
361	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
362		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
363			continue;
364		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
365			return 0;
366	}
367
368	/* ingress filters on outer source */
369	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
370		struct sockaddr_in sin;
371		struct rtentry *rt;
372
373		bzero(&sin, sizeof(sin));
374		sin.sin_family = AF_INET;
375		sin.sin_len = sizeof(struct sockaddr_in);
376		sin.sin_addr = ip->ip_src;
377		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
378		if (!rt || rt->rt_ifp != ifp) {
379#if 0
380			log(LOG_WARNING, "%s: packet from 0x%x dropped "
381			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
382			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
383#endif
384			if (rt)
385				rtfree(rt);
386			return 0;
387		}
388		rtfree(rt);
389	}
390
391	return 32 * 2;
392}
393
394/*
395 * we know that we are in IFF_UP, outer address available, and outer family
396 * matched the physical addr family.  see gif_encapcheck().
397 */
398int
399gif_encapcheck4(m, off, proto, arg)
400	const struct mbuf *m;
401	int off;
402	int proto;
403	void *arg;
404{
405	struct ip ip;
406	struct gif_softc *sc;
407	struct ifnet *ifp;
408
409	/* sanity check done in caller */
410	sc = (struct gif_softc *)arg;
411
412	/* LINTED const cast */
413	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
414	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
415
416	return gif_validate4(&ip, sc, ifp);
417}
418
419int
420in_gif_attach(sc)
421	struct gif_softc *sc;
422{
423	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
424	    &in_gif_protosw, sc);
425	if (sc->encap_cookie4 == NULL)
426		return EEXIST;
427	return 0;
428}
429
430int
431in_gif_detach(sc)
432	struct gif_softc *sc;
433{
434	int error;
435
436	error = encap_detach(sc->encap_cookie4);
437	if (error == 0)
438		sc->encap_cookie4 = NULL;
439	return error;
440}
441