in_gif.c revision 194951 
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 194951 2009-06-25 11:52:33Z rwatson $");
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#include <sys/malloc.h>
49#include <sys/vimage.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#include <netinet/vinet.h>
63
64#ifdef INET6
65#include <netinet/ip6.h>
66#endif
67
68#ifdef MROUTING
69#include <netinet/ip_mroute.h>
70#endif /* MROUTING */
71
72#include <net/if_gif.h>
73
74static int gif_validate4(const struct ip *, struct gif_softc *,
75	struct ifnet *);
76
77extern  struct domain inetdomain;
78struct protosw in_gif_protosw = {
79	.pr_type =		SOCK_RAW,
80	.pr_domain =		&inetdomain,
81	.pr_protocol =		0/* IPPROTO_IPV[46] */,
82	.pr_flags =		PR_ATOMIC|PR_ADDR,
83	.pr_input =		in_gif_input,
84	.pr_output =		(pr_output_t*)rip_output,
85	.pr_ctloutput =		rip_ctloutput,
86	.pr_usrreqs =		&rip_usrreqs
87};
88
89#ifdef VIMAGE_GLOBALS
90extern int ip_gif_ttl;
91#endif
92SYSCTL_V_INT(V_NET, vnet_gif, _net_inet_ip, IPCTL_GIF_TTL, gifttl,
93	CTLFLAG_RW, ip_gif_ttl,	0, "");
94
95int
96in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
97{
98	INIT_VNET_GIF(ifp->if_vnet);
99	struct gif_softc *sc = ifp->if_softc;
100	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
101	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
102	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
103	struct ip iphdr;	/* capsule IP header, host byte ordered */
104	struct etherip_header eiphdr;
105	int error, len, proto;
106	u_int8_t tos;
107
108	GIF_LOCK_ASSERT(sc);
109
110	if (sin_src == NULL || sin_dst == NULL ||
111	    sin_src->sin_family != AF_INET ||
112	    sin_dst->sin_family != AF_INET) {
113		m_freem(m);
114		return EAFNOSUPPORT;
115	}
116
117	switch (family) {
118#ifdef INET
119	case AF_INET:
120	    {
121		struct ip *ip;
122
123		proto = IPPROTO_IPV4;
124		if (m->m_len < sizeof(*ip)) {
125			m = m_pullup(m, sizeof(*ip));
126			if (!m)
127				return ENOBUFS;
128		}
129		ip = mtod(m, struct ip *);
130		tos = ip->ip_tos;
131		break;
132	    }
133#endif /* INET */
134#ifdef INET6
135	case AF_INET6:
136	    {
137		struct ip6_hdr *ip6;
138		proto = IPPROTO_IPV6;
139		if (m->m_len < sizeof(*ip6)) {
140			m = m_pullup(m, sizeof(*ip6));
141			if (!m)
142				return ENOBUFS;
143		}
144		ip6 = mtod(m, struct ip6_hdr *);
145		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
146		break;
147	    }
148#endif /* INET6 */
149	case AF_LINK:
150 		proto = IPPROTO_ETHERIP;
151
152		/*
153		 * GIF_SEND_REVETHIP (disabled by default) intentionally
154		 * sends an EtherIP packet with revered version field in
155		 * the header.  This is a knob for backward compatibility
156		 * with FreeBSD 7.2R or prior.
157		 */
158		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
159 			eiphdr.eip_ver = 0;
160 			eiphdr.eip_resvl = ETHERIP_VERSION;
161 			eiphdr.eip_resvh = 0;
162		} else {
163 			eiphdr.eip_ver = ETHERIP_VERSION;
164 			eiphdr.eip_resvl = 0;
165 			eiphdr.eip_resvh = 0;
166		}
167 		/* prepend Ethernet-in-IP header */
168 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
169 		if (m && m->m_len < sizeof(struct etherip_header))
170 			m = m_pullup(m, sizeof(struct etherip_header));
171 		if (m == NULL)
172 			return ENOBUFS;
173 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
174		    sizeof(struct etherip_header));
175		break;
176
177	default:
178#ifdef DEBUG
179		printf("in_gif_output: warning: unknown family %d passed\n",
180			family);
181#endif
182		m_freem(m);
183		return EAFNOSUPPORT;
184	}
185
186	bzero(&iphdr, sizeof(iphdr));
187	iphdr.ip_src = sin_src->sin_addr;
188	/* bidirectional configured tunnel mode */
189	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
190		iphdr.ip_dst = sin_dst->sin_addr;
191	else {
192		m_freem(m);
193		return ENETUNREACH;
194	}
195	iphdr.ip_p = proto;
196	/* version will be set in ip_output() */
197	iphdr.ip_ttl = V_ip_gif_ttl;
198	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
199	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
200		       &iphdr.ip_tos, &tos);
201
202	/* prepend new IP header */
203	len = sizeof(struct ip);
204#ifndef __NO_STRICT_ALIGNMENT
205	if (family == AF_LINK)
206		len += ETHERIP_ALIGN;
207#endif
208	M_PREPEND(m, len, M_DONTWAIT);
209	if (m != NULL && m->m_len < len)
210		m = m_pullup(m, len);
211	if (m == NULL) {
212		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
213		return ENOBUFS;
214	}
215#ifndef __NO_STRICT_ALIGNMENT
216	if (family == AF_LINK) {
217		len = mtod(m, vm_offset_t) & 3;
218		KASSERT(len == 0 || len == ETHERIP_ALIGN,
219		    ("in_gif_output: unexpected misalignment"));
220		m->m_data += len;
221		m->m_len -= ETHERIP_ALIGN;
222	}
223#endif
224	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
225
226	M_SETFIB(m, sc->gif_fibnum);
227
228	if (dst->sin_family != sin_dst->sin_family ||
229	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
230		/* cache route doesn't match */
231		bzero(dst, sizeof(*dst));
232		dst->sin_family = sin_dst->sin_family;
233		dst->sin_len = sizeof(struct sockaddr_in);
234		dst->sin_addr = sin_dst->sin_addr;
235		if (sc->gif_ro.ro_rt) {
236			RTFREE(sc->gif_ro.ro_rt);
237			sc->gif_ro.ro_rt = NULL;
238		}
239#if 0
240		GIF2IFP(sc)->if_mtu = GIF_MTU;
241#endif
242	}
243
244	if (sc->gif_ro.ro_rt == NULL) {
245		in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
246		if (sc->gif_ro.ro_rt == NULL) {
247			m_freem(m);
248			return ENETUNREACH;
249		}
250
251		/* if it constitutes infinite encapsulation, punt. */
252		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
253			m_freem(m);
254			return ENETUNREACH;	/* XXX */
255		}
256#if 0
257		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
258			- sizeof(struct ip);
259#endif
260	}
261
262	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
263
264	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
265	    sc->gif_ro.ro_rt != NULL) {
266		RTFREE(sc->gif_ro.ro_rt);
267		sc->gif_ro.ro_rt = NULL;
268	}
269
270	return (error);
271}
272
273void
274in_gif_input(struct mbuf *m, int off)
275{
276	INIT_VNET_INET(curvnet);
277	struct ifnet *gifp = NULL;
278	struct gif_softc *sc;
279	struct ip *ip;
280	int af;
281	u_int8_t otos;
282	int proto;
283
284	ip = mtod(m, struct ip *);
285	proto = ip->ip_p;
286
287	sc = (struct gif_softc *)encap_getarg(m);
288	if (sc == NULL) {
289		m_freem(m);
290		IPSTAT_INC(ips_nogif);
291		return;
292	}
293
294	gifp = GIF2IFP(sc);
295	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
296		m_freem(m);
297		IPSTAT_INC(ips_nogif);
298		return;
299	}
300
301	otos = ip->ip_tos;
302	m_adj(m, off);
303
304	switch (proto) {
305#ifdef INET
306	case IPPROTO_IPV4:
307	    {
308		struct ip *ip;
309		af = AF_INET;
310		if (m->m_len < sizeof(*ip)) {
311			m = m_pullup(m, sizeof(*ip));
312			if (!m)
313				return;
314		}
315		ip = mtod(m, struct ip *);
316		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
317				  ECN_ALLOWED : ECN_NOCARE,
318				  &otos, &ip->ip_tos) == 0) {
319			m_freem(m);
320			return;
321		}
322		break;
323	    }
324#endif
325#ifdef INET6
326	case IPPROTO_IPV6:
327	    {
328		struct ip6_hdr *ip6;
329		u_int8_t itos, oitos;
330
331		af = AF_INET6;
332		if (m->m_len < sizeof(*ip6)) {
333			m = m_pullup(m, sizeof(*ip6));
334			if (!m)
335				return;
336		}
337		ip6 = mtod(m, struct ip6_hdr *);
338		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
339		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
340				  ECN_ALLOWED : ECN_NOCARE,
341				  &otos, &itos) == 0) {
342			m_freem(m);
343			return;
344		}
345		if (itos != oitos) {
346			ip6->ip6_flow &= ~htonl(0xff << 20);
347			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
348		}
349		break;
350	    }
351#endif /* INET6 */
352 	case IPPROTO_ETHERIP:
353 		af = AF_LINK;
354 		break;
355
356	default:
357		IPSTAT_INC(ips_nogif);
358		m_freem(m);
359		return;
360	}
361	gif_input(m, af, gifp);
362	return;
363}
364
365/*
366 * validate outer address.
367 */
368static int
369gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
370{
371	INIT_VNET_INET(curvnet);
372	struct sockaddr_in *src, *dst;
373	struct in_ifaddr *ia4;
374
375	src = (struct sockaddr_in *)sc->gif_psrc;
376	dst = (struct sockaddr_in *)sc->gif_pdst;
377
378	/* check for address match */
379	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
380	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
381		return 0;
382
383	/* martian filters on outer source - NOT done in ip_input! */
384	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
385		return 0;
386	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
387	case 0: case 127: case 255:
388		return 0;
389	}
390
391	/* reject packets with broadcast on source */
392	/* XXXRW: should use hash lists? */
393	IN_IFADDR_RLOCK();
394	TAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
395		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
396			continue;
397		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
398			IN_IFADDR_RUNLOCK();
399			return 0;
400		}
401	}
402	IN_IFADDR_RUNLOCK();
403
404	/* ingress filters on outer source */
405	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
406		struct sockaddr_in sin;
407		struct rtentry *rt;
408
409		bzero(&sin, sizeof(sin));
410		sin.sin_family = AF_INET;
411		sin.sin_len = sizeof(struct sockaddr_in);
412		sin.sin_addr = ip->ip_src;
413		/* XXX MRT  check for the interface we would use on output */
414		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
415		    0UL, sc->gif_fibnum);
416		if (!rt || rt->rt_ifp != ifp) {
417#if 0
418			log(LOG_WARNING, "%s: packet from 0x%x dropped "
419			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
420			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
421#endif
422			if (rt)
423				RTFREE_LOCKED(rt);
424			return 0;
425		}
426		RTFREE_LOCKED(rt);
427	}
428
429	return 32 * 2;
430}
431
432/*
433 * we know that we are in IFF_UP, outer address available, and outer family
434 * matched the physical addr family.  see gif_encapcheck().
435 */
436int
437gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
438{
439	struct ip ip;
440	struct gif_softc *sc;
441	struct ifnet *ifp;
442
443	/* sanity check done in caller */
444	sc = (struct gif_softc *)arg;
445
446	/* LINTED const cast */
447	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
448	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
449
450	return gif_validate4(&ip, sc, ifp);
451}
452
453int
454in_gif_attach(struct gif_softc *sc)
455{
456	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
457	    &in_gif_protosw, sc);
458	if (sc->encap_cookie4 == NULL)
459		return EEXIST;
460	return 0;
461}
462
463int
464in_gif_detach(struct gif_softc *sc)
465{
466	int error;
467
468	error = encap_detach(sc->encap_cookie4);
469	if (error == 0)
470		sc->encap_cookie4 = NULL;
471	return error;
472}
473