in_gif.c revision 178888 
1/*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $	*/
2
3/*-
4 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the project nor the names of its contributors
16 *    may be used to endorse or promote products derived from this software
17 *    without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/netinet/in_gif.c 178888 2008-05-09 23:03:00Z julian $");
34
35#include "opt_mrouting.h"
36#include "opt_inet.h"
37#include "opt_inet6.h"
38
39#include <sys/param.h>
40#include <sys/systm.h>
41#include <sys/socket.h>
42#include <sys/sockio.h>
43#include <sys/mbuf.h>
44#include <sys/errno.h>
45#include <sys/kernel.h>
46#include <sys/sysctl.h>
47#include <sys/protosw.h>
48
49#include <sys/malloc.h>
50
51#include <net/if.h>
52#include <net/route.h>
53
54#include <netinet/in.h>
55#include <netinet/in_systm.h>
56#include <netinet/ip.h>
57#include <netinet/ip_var.h>
58#include <netinet/in_gif.h>
59#include <netinet/in_var.h>
60#include <netinet/ip_encap.h>
61#include <netinet/ip_ecn.h>
62
63#ifdef INET6
64#include <netinet/ip6.h>
65#endif
66
67#ifdef MROUTING
68#include <netinet/ip_mroute.h>
69#endif /* MROUTING */
70
71#include <net/if_gif.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(struct ifnet *ifp, int family, struct mbuf *m)
94{
95	struct gif_softc *sc = ifp->if_softc;
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	struct etherip_header eiphdr;
101	int proto, error;
102	u_int8_t tos;
103
104	GIF_LOCK_ASSERT(sc);
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	case AF_LINK:
146 		proto = IPPROTO_ETHERIP;
147 		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
148 		eiphdr.eip_pad = 0;
149 		/* prepend Ethernet-in-IP header */
150 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
151 		if (m && m->m_len < sizeof(struct etherip_header))
152 			m = m_pullup(m, sizeof(struct etherip_header));
153 		if (m == NULL)
154 			return ENOBUFS;
155 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
156		    sizeof(struct etherip_header));
157		break;
158
159	default:
160#ifdef DEBUG
161		printf("in_gif_output: warning: unknown family %d passed\n",
162			family);
163#endif
164		m_freem(m);
165		return EAFNOSUPPORT;
166	}
167
168	bzero(&iphdr, sizeof(iphdr));
169	iphdr.ip_src = sin_src->sin_addr;
170	/* bidirectional configured tunnel mode */
171	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
172		iphdr.ip_dst = sin_dst->sin_addr;
173	else {
174		m_freem(m);
175		return ENETUNREACH;
176	}
177	iphdr.ip_p = proto;
178	/* version will be set in ip_output() */
179	iphdr.ip_ttl = ip_gif_ttl;
180	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
181	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
182		       &iphdr.ip_tos, &tos);
183
184	/* prepend new IP header */
185	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
186	if (m && m->m_len < sizeof(struct ip))
187		m = m_pullup(m, sizeof(struct ip));
188	if (m == NULL) {
189		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
190		return ENOBUFS;
191	}
192	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
193
194	M_SETFIB(m, sc->gif_fibnum);
195
196	if (dst->sin_family != sin_dst->sin_family ||
197	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
198		/* cache route doesn't match */
199		bzero(dst, sizeof(*dst));
200		dst->sin_family = sin_dst->sin_family;
201		dst->sin_len = sizeof(struct sockaddr_in);
202		dst->sin_addr = sin_dst->sin_addr;
203		if (sc->gif_ro.ro_rt) {
204			RTFREE(sc->gif_ro.ro_rt);
205			sc->gif_ro.ro_rt = NULL;
206		}
207#if 0
208		GIF2IFP(sc)->if_mtu = GIF_MTU;
209#endif
210	}
211
212	if (sc->gif_ro.ro_rt == NULL) {
213		in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
214		if (sc->gif_ro.ro_rt == NULL) {
215			m_freem(m);
216			return ENETUNREACH;
217		}
218
219		/* if it constitutes infinite encapsulation, punt. */
220		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
221			m_freem(m);
222			return ENETUNREACH;	/* XXX */
223		}
224#if 0
225		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
226			- sizeof(struct ip);
227#endif
228	}
229
230	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
231
232	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
233	    sc->gif_ro.ro_rt != NULL) {
234		RTFREE(sc->gif_ro.ro_rt);
235		sc->gif_ro.ro_rt = NULL;
236	}
237
238	return (error);
239}
240
241void
242in_gif_input(struct mbuf *m, int off)
243{
244	struct ifnet *gifp = NULL;
245	struct gif_softc *sc;
246	struct ip *ip;
247	int af;
248	u_int8_t otos;
249	int proto;
250
251	ip = mtod(m, struct ip *);
252	proto = ip->ip_p;
253
254	sc = (struct gif_softc *)encap_getarg(m);
255	if (sc == NULL) {
256		m_freem(m);
257		ipstat.ips_nogif++;
258		return;
259	}
260
261	gifp = GIF2IFP(sc);
262	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
263		m_freem(m);
264		ipstat.ips_nogif++;
265		return;
266	}
267
268	otos = ip->ip_tos;
269	m_adj(m, off);
270
271	switch (proto) {
272#ifdef INET
273	case IPPROTO_IPV4:
274	    {
275		struct ip *ip;
276		af = AF_INET;
277		if (m->m_len < sizeof(*ip)) {
278			m = m_pullup(m, sizeof(*ip));
279			if (!m)
280				return;
281		}
282		ip = mtod(m, struct ip *);
283		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
284				  ECN_ALLOWED : ECN_NOCARE,
285				  &otos, &ip->ip_tos) == 0) {
286			m_freem(m);
287			return;
288		}
289		break;
290	    }
291#endif
292#ifdef INET6
293	case IPPROTO_IPV6:
294	    {
295		struct ip6_hdr *ip6;
296		u_int8_t itos, oitos;
297
298		af = AF_INET6;
299		if (m->m_len < sizeof(*ip6)) {
300			m = m_pullup(m, sizeof(*ip6));
301			if (!m)
302				return;
303		}
304		ip6 = mtod(m, struct ip6_hdr *);
305		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
306		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
307				  ECN_ALLOWED : ECN_NOCARE,
308				  &otos, &itos) == 0) {
309			m_freem(m);
310			return;
311		}
312		if (itos != oitos) {
313			ip6->ip6_flow &= ~htonl(0xff << 20);
314			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
315		}
316		break;
317	    }
318#endif /* INET6 */
319 	case IPPROTO_ETHERIP:
320 		af = AF_LINK;
321 		break;
322
323	default:
324		ipstat.ips_nogif++;
325		m_freem(m);
326		return;
327	}
328	gif_input(m, af, gifp);
329	return;
330}
331
332/*
333 * validate outer address.
334 */
335static int
336gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
337{
338	struct sockaddr_in *src, *dst;
339	struct in_ifaddr *ia4;
340
341	src = (struct sockaddr_in *)sc->gif_psrc;
342	dst = (struct sockaddr_in *)sc->gif_pdst;
343
344	/* check for address match */
345	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
346	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
347		return 0;
348
349	/* martian filters on outer source - NOT done in ip_input! */
350	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
351		return 0;
352	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
353	case 0: case 127: case 255:
354		return 0;
355	}
356	/* reject packets with broadcast on source */
357	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
358		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
359			continue;
360		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
361			return 0;
362	}
363
364	/* ingress filters on outer source */
365	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
366		struct sockaddr_in sin;
367		struct rtentry *rt;
368
369		bzero(&sin, sizeof(sin));
370		sin.sin_family = AF_INET;
371		sin.sin_len = sizeof(struct sockaddr_in);
372		sin.sin_addr = ip->ip_src;
373		/* XXX MRT  check for the interface we would use on output */
374		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
375		    0UL, sc->gif_fibnum);
376		if (!rt || rt->rt_ifp != ifp) {
377#if 0
378			log(LOG_WARNING, "%s: packet from 0x%x dropped "
379			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
380			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
381#endif
382			if (rt)
383				RTFREE_LOCKED(rt);
384			return 0;
385		}
386		RTFREE_LOCKED(rt);
387	}
388
389	return 32 * 2;
390}
391
392/*
393 * we know that we are in IFF_UP, outer address available, and outer family
394 * matched the physical addr family.  see gif_encapcheck().
395 */
396int
397gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
398{
399	struct ip ip;
400	struct gif_softc *sc;
401	struct ifnet *ifp;
402
403	/* sanity check done in caller */
404	sc = (struct gif_softc *)arg;
405
406	/* LINTED const cast */
407	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
408	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
409
410	return gif_validate4(&ip, sc, ifp);
411}
412
413int
414in_gif_attach(struct gif_softc *sc)
415{
416	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
417	    &in_gif_protosw, sc);
418	if (sc->encap_cookie4 == NULL)
419		return EEXIST;
420	return 0;
421}
422
423int
424in_gif_detach(struct gif_softc *sc)
425{
426	int error;
427
428	error = encap_detach(sc->encap_cookie4);
429	if (error == 0)
430		sc->encap_cookie4 = NULL;
431	return error;
432}
433