in_gif.c revision 189494 
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 189494 2009-03-07 19:08:58Z marius $");
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 		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
152 		eiphdr.eip_pad = 0;
153 		/* prepend Ethernet-in-IP header */
154 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
155 		if (m && m->m_len < sizeof(struct etherip_header))
156 			m = m_pullup(m, sizeof(struct etherip_header));
157 		if (m == NULL)
158 			return ENOBUFS;
159 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
160		    sizeof(struct etherip_header));
161		break;
162
163	default:
164#ifdef DEBUG
165		printf("in_gif_output: warning: unknown family %d passed\n",
166			family);
167#endif
168		m_freem(m);
169		return EAFNOSUPPORT;
170	}
171
172	bzero(&iphdr, sizeof(iphdr));
173	iphdr.ip_src = sin_src->sin_addr;
174	/* bidirectional configured tunnel mode */
175	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
176		iphdr.ip_dst = sin_dst->sin_addr;
177	else {
178		m_freem(m);
179		return ENETUNREACH;
180	}
181	iphdr.ip_p = proto;
182	/* version will be set in ip_output() */
183	iphdr.ip_ttl = V_ip_gif_ttl;
184	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
185	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
186		       &iphdr.ip_tos, &tos);
187
188	/* prepend new IP header */
189	len = sizeof(struct ip);
190#ifndef __NO_STRICT_ALIGNMENT
191	if (family == AF_LINK)
192		len += ETHERIP_ALIGN;
193#endif
194	M_PREPEND(m, len, M_DONTWAIT);
195	if (m != NULL && m->m_len < len)
196		m = m_pullup(m, len);
197	if (m == NULL) {
198		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
199		return ENOBUFS;
200	}
201#ifndef __NO_STRICT_ALIGNMENT
202	if (family == AF_LINK) {
203		len = mtod(m, vm_offset_t) & 3;
204		KASSERT(len == 0 || len == ETHERIP_ALIGN,
205		    ("in_gif_output: unexpected misalignment"));
206		m->m_data += len;
207		m->m_len -= ETHERIP_ALIGN;
208	}
209#endif
210	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
211
212	M_SETFIB(m, sc->gif_fibnum);
213
214	if (dst->sin_family != sin_dst->sin_family ||
215	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
216		/* cache route doesn't match */
217		bzero(dst, sizeof(*dst));
218		dst->sin_family = sin_dst->sin_family;
219		dst->sin_len = sizeof(struct sockaddr_in);
220		dst->sin_addr = sin_dst->sin_addr;
221		if (sc->gif_ro.ro_rt) {
222			RTFREE(sc->gif_ro.ro_rt);
223			sc->gif_ro.ro_rt = NULL;
224		}
225#if 0
226		GIF2IFP(sc)->if_mtu = GIF_MTU;
227#endif
228	}
229
230	if (sc->gif_ro.ro_rt == NULL) {
231		in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
232		if (sc->gif_ro.ro_rt == NULL) {
233			m_freem(m);
234			return ENETUNREACH;
235		}
236
237		/* if it constitutes infinite encapsulation, punt. */
238		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
239			m_freem(m);
240			return ENETUNREACH;	/* XXX */
241		}
242#if 0
243		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
244			- sizeof(struct ip);
245#endif
246	}
247
248	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
249
250	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
251	    sc->gif_ro.ro_rt != NULL) {
252		RTFREE(sc->gif_ro.ro_rt);
253		sc->gif_ro.ro_rt = NULL;
254	}
255
256	return (error);
257}
258
259void
260in_gif_input(struct mbuf *m, int off)
261{
262	INIT_VNET_INET(curvnet);
263	struct ifnet *gifp = NULL;
264	struct gif_softc *sc;
265	struct ip *ip;
266	int af;
267	u_int8_t otos;
268	int proto;
269
270	ip = mtod(m, struct ip *);
271	proto = ip->ip_p;
272
273	sc = (struct gif_softc *)encap_getarg(m);
274	if (sc == NULL) {
275		m_freem(m);
276		V_ipstat.ips_nogif++;
277		return;
278	}
279
280	gifp = GIF2IFP(sc);
281	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
282		m_freem(m);
283		V_ipstat.ips_nogif++;
284		return;
285	}
286
287	otos = ip->ip_tos;
288	m_adj(m, off);
289
290	switch (proto) {
291#ifdef INET
292	case IPPROTO_IPV4:
293	    {
294		struct ip *ip;
295		af = AF_INET;
296		if (m->m_len < sizeof(*ip)) {
297			m = m_pullup(m, sizeof(*ip));
298			if (!m)
299				return;
300		}
301		ip = mtod(m, struct ip *);
302		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
303				  ECN_ALLOWED : ECN_NOCARE,
304				  &otos, &ip->ip_tos) == 0) {
305			m_freem(m);
306			return;
307		}
308		break;
309	    }
310#endif
311#ifdef INET6
312	case IPPROTO_IPV6:
313	    {
314		struct ip6_hdr *ip6;
315		u_int8_t itos, oitos;
316
317		af = AF_INET6;
318		if (m->m_len < sizeof(*ip6)) {
319			m = m_pullup(m, sizeof(*ip6));
320			if (!m)
321				return;
322		}
323		ip6 = mtod(m, struct ip6_hdr *);
324		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
325		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
326				  ECN_ALLOWED : ECN_NOCARE,
327				  &otos, &itos) == 0) {
328			m_freem(m);
329			return;
330		}
331		if (itos != oitos) {
332			ip6->ip6_flow &= ~htonl(0xff << 20);
333			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
334		}
335		break;
336	    }
337#endif /* INET6 */
338 	case IPPROTO_ETHERIP:
339 		af = AF_LINK;
340 		break;
341
342	default:
343		V_ipstat.ips_nogif++;
344		m_freem(m);
345		return;
346	}
347	gif_input(m, af, gifp);
348	return;
349}
350
351/*
352 * validate outer address.
353 */
354static int
355gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
356{
357	INIT_VNET_INET(curvnet);
358	struct sockaddr_in *src, *dst;
359	struct in_ifaddr *ia4;
360
361	src = (struct sockaddr_in *)sc->gif_psrc;
362	dst = (struct sockaddr_in *)sc->gif_pdst;
363
364	/* check for address match */
365	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
366	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
367		return 0;
368
369	/* martian filters on outer source - NOT done in ip_input! */
370	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
371		return 0;
372	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
373	case 0: case 127: case 255:
374		return 0;
375	}
376	/* reject packets with broadcast on source */
377	TAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
378		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
379			continue;
380		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
381			return 0;
382	}
383
384	/* ingress filters on outer source */
385	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
386		struct sockaddr_in sin;
387		struct rtentry *rt;
388
389		bzero(&sin, sizeof(sin));
390		sin.sin_family = AF_INET;
391		sin.sin_len = sizeof(struct sockaddr_in);
392		sin.sin_addr = ip->ip_src;
393		/* XXX MRT  check for the interface we would use on output */
394		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
395		    0UL, sc->gif_fibnum);
396		if (!rt || rt->rt_ifp != ifp) {
397#if 0
398			log(LOG_WARNING, "%s: packet from 0x%x dropped "
399			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
400			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
401#endif
402			if (rt)
403				RTFREE_LOCKED(rt);
404			return 0;
405		}
406		RTFREE_LOCKED(rt);
407	}
408
409	return 32 * 2;
410}
411
412/*
413 * we know that we are in IFF_UP, outer address available, and outer family
414 * matched the physical addr family.  see gif_encapcheck().
415 */
416int
417gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
418{
419	struct ip ip;
420	struct gif_softc *sc;
421	struct ifnet *ifp;
422
423	/* sanity check done in caller */
424	sc = (struct gif_softc *)arg;
425
426	/* LINTED const cast */
427	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
428	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
429
430	return gif_validate4(&ip, sc, ifp);
431}
432
433int
434in_gif_attach(struct gif_softc *sc)
435{
436	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
437	    &in_gif_protosw, sc);
438	if (sc->encap_cookie4 == NULL)
439		return EEXIST;
440	return 0;
441}
442
443int
444in_gif_detach(struct gif_softc *sc)
445{
446	int error;
447
448	error = encap_detach(sc->encap_cookie4);
449	if (error == 0)
450		sc->encap_cookie4 = NULL;
451	return error;
452}
453