in_gif.c revision 169454 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 169454 2007-05-10 15:58:48Z rwatson $	*/
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
71static int gif_validate4(const struct ip *, struct gif_softc *,
72	struct ifnet *);
73
74extern  struct domain inetdomain;
75struct protosw in_gif_protosw = {
76	.pr_type =		SOCK_RAW,
77	.pr_domain =		&inetdomain,
78	.pr_protocol =		0/* IPPROTO_IPV[46] */,
79	.pr_flags =		PR_ATOMIC|PR_ADDR,
80	.pr_input =		in_gif_input,
81	.pr_output =		(pr_output_t*)rip_output,
82	.pr_ctloutput =		rip_ctloutput,
83	.pr_usrreqs =		&rip_usrreqs
84};
85
86static int ip_gif_ttl = GIF_TTL;
87SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
88	&ip_gif_ttl,	0, "");
89
90int
91in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
92{
93	struct gif_softc *sc = ifp->if_softc;
94	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
95	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
96	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
97	struct ip iphdr;	/* capsule IP header, host byte ordered */
98	struct etherip_header eiphdr;
99	int proto, error;
100	u_int8_t tos;
101
102	GIF_LOCK_ASSERT(sc);
103
104	if (sin_src == NULL || sin_dst == NULL ||
105	    sin_src->sin_family != AF_INET ||
106	    sin_dst->sin_family != AF_INET) {
107		m_freem(m);
108		return EAFNOSUPPORT;
109	}
110
111	switch (family) {
112#ifdef INET
113	case AF_INET:
114	    {
115		struct ip *ip;
116
117		proto = IPPROTO_IPV4;
118		if (m->m_len < sizeof(*ip)) {
119			m = m_pullup(m, sizeof(*ip));
120			if (!m)
121				return ENOBUFS;
122		}
123		ip = mtod(m, struct ip *);
124		tos = ip->ip_tos;
125		break;
126	    }
127#endif /* INET */
128#ifdef INET6
129	case AF_INET6:
130	    {
131		struct ip6_hdr *ip6;
132		proto = IPPROTO_IPV6;
133		if (m->m_len < sizeof(*ip6)) {
134			m = m_pullup(m, sizeof(*ip6));
135			if (!m)
136				return ENOBUFS;
137		}
138		ip6 = mtod(m, struct ip6_hdr *);
139		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
140		break;
141	    }
142#endif /* INET6 */
143	case AF_LINK:
144 		proto = IPPROTO_ETHERIP;
145 		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
146 		eiphdr.eip_pad = 0;
147 		/* prepend Ethernet-in-IP header */
148 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
149 		if (m && m->m_len < sizeof(struct etherip_header))
150 			m = m_pullup(m, sizeof(struct etherip_header));
151 		if (m == NULL)
152 			return ENOBUFS;
153 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
154		    sizeof(struct etherip_header));
155		break;
156
157	default:
158#ifdef DEBUG
159		printf("in_gif_output: warning: unknown family %d passed\n",
160			family);
161#endif
162		m_freem(m);
163		return EAFNOSUPPORT;
164	}
165
166	bzero(&iphdr, sizeof(iphdr));
167	iphdr.ip_src = sin_src->sin_addr;
168	/* bidirectional configured tunnel mode */
169	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
170		iphdr.ip_dst = sin_dst->sin_addr;
171	else {
172		m_freem(m);
173		return ENETUNREACH;
174	}
175	iphdr.ip_p = proto;
176	/* version will be set in ip_output() */
177	iphdr.ip_ttl = ip_gif_ttl;
178	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
179	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
180		       &iphdr.ip_tos, &tos);
181
182	/* prepend new IP header */
183	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
184	if (m && m->m_len < sizeof(struct ip))
185		m = m_pullup(m, sizeof(struct ip));
186	if (m == NULL) {
187		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
188		return ENOBUFS;
189	}
190	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
191
192	if (dst->sin_family != sin_dst->sin_family ||
193	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
194		/* cache route doesn't match */
195		bzero(dst, sizeof(*dst));
196		dst->sin_family = sin_dst->sin_family;
197		dst->sin_len = sizeof(struct sockaddr_in);
198		dst->sin_addr = sin_dst->sin_addr;
199		if (sc->gif_ro.ro_rt) {
200			RTFREE(sc->gif_ro.ro_rt);
201			sc->gif_ro.ro_rt = NULL;
202		}
203#if 0
204		GIF2IFP(sc)->if_mtu = GIF_MTU;
205#endif
206	}
207
208	if (sc->gif_ro.ro_rt == NULL) {
209		rtalloc_ign(&sc->gif_ro, 0);
210		if (sc->gif_ro.ro_rt == NULL) {
211			m_freem(m);
212			return ENETUNREACH;
213		}
214
215		/* if it constitutes infinite encapsulation, punt. */
216		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
217			m_freem(m);
218			return ENETUNREACH;	/* XXX */
219		}
220#if 0
221		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
222			- sizeof(struct ip);
223#endif
224	}
225
226	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
227
228	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
229	    sc->gif_ro.ro_rt != NULL) {
230		RTFREE(sc->gif_ro.ro_rt);
231		sc->gif_ro.ro_rt = NULL;
232	}
233
234	return (error);
235}
236
237void
238in_gif_input(struct mbuf *m, int off)
239{
240	struct ifnet *gifp = NULL;
241	struct gif_softc *sc;
242	struct ip *ip;
243	int af;
244	u_int8_t otos;
245	int proto;
246
247	ip = mtod(m, struct ip *);
248	proto = ip->ip_p;
249
250	sc = (struct gif_softc *)encap_getarg(m);
251	if (sc == NULL) {
252		m_freem(m);
253		ipstat.ips_nogif++;
254		return;
255	}
256
257	gifp = GIF2IFP(sc);
258	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
259		m_freem(m);
260		ipstat.ips_nogif++;
261		return;
262	}
263
264	otos = ip->ip_tos;
265	m_adj(m, off);
266
267	switch (proto) {
268#ifdef INET
269	case IPPROTO_IPV4:
270	    {
271		struct ip *ip;
272		af = AF_INET;
273		if (m->m_len < sizeof(*ip)) {
274			m = m_pullup(m, sizeof(*ip));
275			if (!m)
276				return;
277		}
278		ip = mtod(m, struct ip *);
279		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
280				  ECN_ALLOWED : ECN_NOCARE,
281				  &otos, &ip->ip_tos) == 0) {
282			m_freem(m);
283			return;
284		}
285		break;
286	    }
287#endif
288#ifdef INET6
289	case IPPROTO_IPV6:
290	    {
291		struct ip6_hdr *ip6;
292		u_int8_t itos, oitos;
293
294		af = AF_INET6;
295		if (m->m_len < sizeof(*ip6)) {
296			m = m_pullup(m, sizeof(*ip6));
297			if (!m)
298				return;
299		}
300		ip6 = mtod(m, struct ip6_hdr *);
301		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
302		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
303				  ECN_ALLOWED : ECN_NOCARE,
304				  &otos, &itos) == 0) {
305			m_freem(m);
306			return;
307		}
308		if (itos != oitos) {
309			ip6->ip6_flow &= ~htonl(0xff << 20);
310			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
311		}
312		break;
313	    }
314#endif /* INET6 */
315 	case IPPROTO_ETHERIP:
316 		af = AF_LINK;
317 		break;
318
319	default:
320		ipstat.ips_nogif++;
321		m_freem(m);
322		return;
323	}
324	gif_input(m, af, gifp);
325	return;
326}
327
328/*
329 * validate outer address.
330 */
331static int
332gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
333{
334	struct sockaddr_in *src, *dst;
335	struct in_ifaddr *ia4;
336
337	src = (struct sockaddr_in *)sc->gif_psrc;
338	dst = (struct sockaddr_in *)sc->gif_pdst;
339
340	/* check for address match */
341	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
342	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
343		return 0;
344
345	/* martian filters on outer source - NOT done in ip_input! */
346	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
347		return 0;
348	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
349	case 0: case 127: case 255:
350		return 0;
351	}
352	/* reject packets with broadcast on source */
353	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
354		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
355			continue;
356		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
357			return 0;
358	}
359
360	/* ingress filters on outer source */
361	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
362		struct sockaddr_in sin;
363		struct rtentry *rt;
364
365		bzero(&sin, sizeof(sin));
366		sin.sin_family = AF_INET;
367		sin.sin_len = sizeof(struct sockaddr_in);
368		sin.sin_addr = ip->ip_src;
369		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
370		if (!rt || rt->rt_ifp != ifp) {
371#if 0
372			log(LOG_WARNING, "%s: packet from 0x%x dropped "
373			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
374			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
375#endif
376			if (rt)
377				rtfree(rt);
378			return 0;
379		}
380		rtfree(rt);
381	}
382
383	return 32 * 2;
384}
385
386/*
387 * we know that we are in IFF_UP, outer address available, and outer family
388 * matched the physical addr family.  see gif_encapcheck().
389 */
390int
391gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
392{
393	struct ip ip;
394	struct gif_softc *sc;
395	struct ifnet *ifp;
396
397	/* sanity check done in caller */
398	sc = (struct gif_softc *)arg;
399
400	/* LINTED const cast */
401	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
402	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
403
404	return gif_validate4(&ip, sc, ifp);
405}
406
407int
408in_gif_attach(struct gif_softc *sc)
409{
410	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
411	    &in_gif_protosw, sc);
412	if (sc->encap_cookie4 == NULL)
413		return EEXIST;
414	return 0;
415}
416
417int
418in_gif_detach(struct gif_softc *sc)
419{
420	int error;
421
422	error = encap_detach(sc->encap_cookie4);
423	if (error == 0)
424		sc->encap_cookie4 = NULL;
425	return error;
426}
427