in_gif.c revision 196039 
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 196039 2009-08-02 19:43:32Z 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
50#include <net/if.h>
51#include <net/route.h>
52#include <net/vnet.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
88SYSCTL_VNET_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
89	&VNET_NAME(ip_gif_ttl), 0, "");
90
91int
92in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
93{
94	struct gif_softc *sc = ifp->if_softc;
95	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
96	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
97	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
98	struct ip iphdr;	/* capsule IP header, host byte ordered */
99	struct etherip_header eiphdr;
100	int error, len, proto;
101	u_int8_t tos;
102
103	GIF_LOCK_ASSERT(sc);
104
105	if (sin_src == NULL || sin_dst == NULL ||
106	    sin_src->sin_family != AF_INET ||
107	    sin_dst->sin_family != AF_INET) {
108		m_freem(m);
109		return EAFNOSUPPORT;
110	}
111
112	switch (family) {
113#ifdef INET
114	case AF_INET:
115	    {
116		struct ip *ip;
117
118		proto = IPPROTO_IPV4;
119		if (m->m_len < sizeof(*ip)) {
120			m = m_pullup(m, sizeof(*ip));
121			if (!m)
122				return ENOBUFS;
123		}
124		ip = mtod(m, struct ip *);
125		tos = ip->ip_tos;
126		break;
127	    }
128#endif /* INET */
129#ifdef INET6
130	case AF_INET6:
131	    {
132		struct ip6_hdr *ip6;
133		proto = IPPROTO_IPV6;
134		if (m->m_len < sizeof(*ip6)) {
135			m = m_pullup(m, sizeof(*ip6));
136			if (!m)
137				return ENOBUFS;
138		}
139		ip6 = mtod(m, struct ip6_hdr *);
140		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
141		break;
142	    }
143#endif /* INET6 */
144	case AF_LINK:
145 		proto = IPPROTO_ETHERIP;
146
147		/*
148		 * GIF_SEND_REVETHIP (disabled by default) intentionally
149		 * sends an EtherIP packet with revered version field in
150		 * the header.  This is a knob for backward compatibility
151		 * with FreeBSD 7.2R or prior.
152		 */
153		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
154 			eiphdr.eip_ver = 0;
155 			eiphdr.eip_resvl = ETHERIP_VERSION;
156 			eiphdr.eip_resvh = 0;
157		} else {
158 			eiphdr.eip_ver = ETHERIP_VERSION;
159 			eiphdr.eip_resvl = 0;
160 			eiphdr.eip_resvh = 0;
161		}
162 		/* prepend Ethernet-in-IP header */
163 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
164 		if (m && m->m_len < sizeof(struct etherip_header))
165 			m = m_pullup(m, sizeof(struct etherip_header));
166 		if (m == NULL)
167 			return ENOBUFS;
168 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
169		    sizeof(struct etherip_header));
170		break;
171
172	default:
173#ifdef DEBUG
174		printf("in_gif_output: warning: unknown family %d passed\n",
175			family);
176#endif
177		m_freem(m);
178		return EAFNOSUPPORT;
179	}
180
181	bzero(&iphdr, sizeof(iphdr));
182	iphdr.ip_src = sin_src->sin_addr;
183	/* bidirectional configured tunnel mode */
184	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
185		iphdr.ip_dst = sin_dst->sin_addr;
186	else {
187		m_freem(m);
188		return ENETUNREACH;
189	}
190	iphdr.ip_p = proto;
191	/* version will be set in ip_output() */
192	iphdr.ip_ttl = V_ip_gif_ttl;
193	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
194	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
195		       &iphdr.ip_tos, &tos);
196
197	/* prepend new IP header */
198	len = sizeof(struct ip);
199#ifndef __NO_STRICT_ALIGNMENT
200	if (family == AF_LINK)
201		len += ETHERIP_ALIGN;
202#endif
203	M_PREPEND(m, len, M_DONTWAIT);
204	if (m != NULL && m->m_len < len)
205		m = m_pullup(m, len);
206	if (m == NULL) {
207		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
208		return ENOBUFS;
209	}
210#ifndef __NO_STRICT_ALIGNMENT
211	if (family == AF_LINK) {
212		len = mtod(m, vm_offset_t) & 3;
213		KASSERT(len == 0 || len == ETHERIP_ALIGN,
214		    ("in_gif_output: unexpected misalignment"));
215		m->m_data += len;
216		m->m_len -= ETHERIP_ALIGN;
217	}
218#endif
219	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
220
221	M_SETFIB(m, sc->gif_fibnum);
222
223	if (dst->sin_family != sin_dst->sin_family ||
224	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
225		/* cache route doesn't match */
226		bzero(dst, sizeof(*dst));
227		dst->sin_family = sin_dst->sin_family;
228		dst->sin_len = sizeof(struct sockaddr_in);
229		dst->sin_addr = sin_dst->sin_addr;
230		if (sc->gif_ro.ro_rt) {
231			RTFREE(sc->gif_ro.ro_rt);
232			sc->gif_ro.ro_rt = NULL;
233		}
234#if 0
235		GIF2IFP(sc)->if_mtu = GIF_MTU;
236#endif
237	}
238
239	if (sc->gif_ro.ro_rt == NULL) {
240		in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
241		if (sc->gif_ro.ro_rt == NULL) {
242			m_freem(m);
243			return ENETUNREACH;
244		}
245
246		/* if it constitutes infinite encapsulation, punt. */
247		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
248			m_freem(m);
249			return ENETUNREACH;	/* XXX */
250		}
251#if 0
252		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
253			- sizeof(struct ip);
254#endif
255	}
256
257	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
258
259	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
260	    sc->gif_ro.ro_rt != NULL) {
261		RTFREE(sc->gif_ro.ro_rt);
262		sc->gif_ro.ro_rt = NULL;
263	}
264
265	return (error);
266}
267
268void
269in_gif_input(struct mbuf *m, int off)
270{
271	struct ifnet *gifp = NULL;
272	struct gif_softc *sc;
273	struct ip *ip;
274	int af;
275	u_int8_t otos;
276	int proto;
277
278	ip = mtod(m, struct ip *);
279	proto = ip->ip_p;
280
281	sc = (struct gif_softc *)encap_getarg(m);
282	if (sc == NULL) {
283		m_freem(m);
284		KMOD_IPSTAT_INC(ips_nogif);
285		return;
286	}
287
288	gifp = GIF2IFP(sc);
289	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
290		m_freem(m);
291		KMOD_IPSTAT_INC(ips_nogif);
292		return;
293	}
294
295	otos = ip->ip_tos;
296	m_adj(m, off);
297
298	switch (proto) {
299#ifdef INET
300	case IPPROTO_IPV4:
301	    {
302		struct ip *ip;
303		af = AF_INET;
304		if (m->m_len < sizeof(*ip)) {
305			m = m_pullup(m, sizeof(*ip));
306			if (!m)
307				return;
308		}
309		ip = mtod(m, struct ip *);
310		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
311				  ECN_ALLOWED : ECN_NOCARE,
312				  &otos, &ip->ip_tos) == 0) {
313			m_freem(m);
314			return;
315		}
316		break;
317	    }
318#endif
319#ifdef INET6
320	case IPPROTO_IPV6:
321	    {
322		struct ip6_hdr *ip6;
323		u_int8_t itos, oitos;
324
325		af = AF_INET6;
326		if (m->m_len < sizeof(*ip6)) {
327			m = m_pullup(m, sizeof(*ip6));
328			if (!m)
329				return;
330		}
331		ip6 = mtod(m, struct ip6_hdr *);
332		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
333		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
334				  ECN_ALLOWED : ECN_NOCARE,
335				  &otos, &itos) == 0) {
336			m_freem(m);
337			return;
338		}
339		if (itos != oitos) {
340			ip6->ip6_flow &= ~htonl(0xff << 20);
341			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
342		}
343		break;
344	    }
345#endif /* INET6 */
346 	case IPPROTO_ETHERIP:
347 		af = AF_LINK;
348 		break;
349
350	default:
351		KMOD_IPSTAT_INC(ips_nogif);
352		m_freem(m);
353		return;
354	}
355	gif_input(m, af, gifp);
356	return;
357}
358
359/*
360 * validate outer address.
361 */
362static int
363gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
364{
365	struct sockaddr_in *src, *dst;
366	struct in_ifaddr *ia4;
367
368	src = (struct sockaddr_in *)sc->gif_psrc;
369	dst = (struct sockaddr_in *)sc->gif_pdst;
370
371	/* check for address match */
372	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
373	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
374		return 0;
375
376	/* martian filters on outer source - NOT done in ip_input! */
377	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
378		return 0;
379	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
380	case 0: case 127: case 255:
381		return 0;
382	}
383
384	/* reject packets with broadcast on source */
385	/* XXXRW: should use hash lists? */
386	IN_IFADDR_RLOCK();
387	TAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
388		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
389			continue;
390		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
391			IN_IFADDR_RUNLOCK();
392			return 0;
393		}
394	}
395	IN_IFADDR_RUNLOCK();
396
397	/* ingress filters on outer source */
398	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
399		struct sockaddr_in sin;
400		struct rtentry *rt;
401
402		bzero(&sin, sizeof(sin));
403		sin.sin_family = AF_INET;
404		sin.sin_len = sizeof(struct sockaddr_in);
405		sin.sin_addr = ip->ip_src;
406		/* XXX MRT  check for the interface we would use on output */
407		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
408		    0UL, sc->gif_fibnum);
409		if (!rt || rt->rt_ifp != ifp) {
410#if 0
411			log(LOG_WARNING, "%s: packet from 0x%x dropped "
412			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
413			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
414#endif
415			if (rt)
416				RTFREE_LOCKED(rt);
417			return 0;
418		}
419		RTFREE_LOCKED(rt);
420	}
421
422	return 32 * 2;
423}
424
425/*
426 * we know that we are in IFF_UP, outer address available, and outer family
427 * matched the physical addr family.  see gif_encapcheck().
428 */
429int
430gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
431{
432	struct ip ip;
433	struct gif_softc *sc;
434	struct ifnet *ifp;
435
436	/* sanity check done in caller */
437	sc = (struct gif_softc *)arg;
438
439	/* LINTED const cast */
440	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
441	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
442
443	return gif_validate4(&ip, sc, ifp);
444}
445
446int
447in_gif_attach(struct gif_softc *sc)
448{
449	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
450	    &in_gif_protosw, sc);
451	if (sc->encap_cookie4 == NULL)
452		return EEXIST;
453	return 0;
454}
455
456int
457in_gif_detach(struct gif_softc *sc)
458{
459	int error;
460
461	error = encap_detach(sc->encap_cookie4);
462	if (error == 0)
463		sc->encap_cookie4 = NULL;
464	return error;
465}
466