in_gif.c revision 273188 
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: releng/10.1/sys/netinet/in_gif.c 273188 2014-10-16 22:00:24Z hrs $");
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
88VNET_DEFINE(int, ip_gif_ttl) = GIF_TTL;
89#define	V_ip_gif_ttl		VNET(ip_gif_ttl)
90SYSCTL_VNET_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
91	&VNET_NAME(ip_gif_ttl), 0, "");
92
93int
94in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
95{
96	struct gif_softc *sc = ifp->if_softc;
97	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
98	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
99	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
100	struct ip iphdr;	/* capsule IP header, host byte ordered */
101	struct etherip_header eiphdr;
102	int error, len, proto;
103	u_int8_t tos;
104
105	GIF_LOCK_ASSERT(sc);
106
107	if (sin_src == NULL || sin_dst == NULL ||
108	    sin_src->sin_family != AF_INET ||
109	    sin_dst->sin_family != AF_INET) {
110		m_freem(m);
111		return EAFNOSUPPORT;
112	}
113
114	switch (family) {
115#ifdef INET
116	case AF_INET:
117	    {
118		struct ip *ip;
119
120		proto = IPPROTO_IPV4;
121		if (m->m_len < sizeof(*ip)) {
122			m = m_pullup(m, sizeof(*ip));
123			if (!m)
124				return ENOBUFS;
125		}
126		ip = mtod(m, struct ip *);
127		tos = ip->ip_tos;
128		break;
129	    }
130#endif /* INET */
131#ifdef INET6
132	case AF_INET6:
133	    {
134		struct ip6_hdr *ip6;
135		proto = IPPROTO_IPV6;
136		if (m->m_len < sizeof(*ip6)) {
137			m = m_pullup(m, sizeof(*ip6));
138			if (!m)
139				return ENOBUFS;
140		}
141		ip6 = mtod(m, struct ip6_hdr *);
142		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
143		break;
144	    }
145#endif /* INET6 */
146	case AF_LINK:
147 		proto = IPPROTO_ETHERIP;
148
149		/*
150		 * GIF_SEND_REVETHIP (disabled by default) intentionally
151		 * sends an EtherIP packet with revered version field in
152		 * the header.  This is a knob for backward compatibility
153		 * with FreeBSD 7.2R or prior.
154		 */
155		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
156 			eiphdr.eip_ver = 0;
157 			eiphdr.eip_resvl = ETHERIP_VERSION;
158 			eiphdr.eip_resvh = 0;
159		} else {
160 			eiphdr.eip_ver = ETHERIP_VERSION;
161 			eiphdr.eip_resvl = 0;
162 			eiphdr.eip_resvh = 0;
163		}
164 		/* prepend Ethernet-in-IP header */
165 		M_PREPEND(m, sizeof(struct etherip_header), M_NOWAIT);
166 		if (m && m->m_len < sizeof(struct etherip_header))
167 			m = m_pullup(m, sizeof(struct etherip_header));
168 		if (m == NULL)
169 			return ENOBUFS;
170 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
171		    sizeof(struct etherip_header));
172		tos = 0;
173		break;
174
175	default:
176#ifdef DEBUG
177		printf("in_gif_output: warning: unknown family %d passed\n",
178			family);
179#endif
180		m_freem(m);
181		return EAFNOSUPPORT;
182	}
183
184	bzero(&iphdr, sizeof(iphdr));
185	iphdr.ip_src = sin_src->sin_addr;
186	/* bidirectional configured tunnel mode */
187	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
188		iphdr.ip_dst = sin_dst->sin_addr;
189	else {
190		m_freem(m);
191		return ENETUNREACH;
192	}
193	iphdr.ip_p = proto;
194	/* version will be set in ip_output() */
195	iphdr.ip_ttl = V_ip_gif_ttl;
196	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
197	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
198		       &iphdr.ip_tos, &tos);
199
200	/* prepend new IP header */
201	len = sizeof(struct ip);
202#ifndef __NO_STRICT_ALIGNMENT
203	if (family == AF_LINK)
204		len += ETHERIP_ALIGN;
205#endif
206	M_PREPEND(m, len, M_NOWAIT);
207	if (m != NULL && m->m_len < len)
208		m = m_pullup(m, len);
209	if (m == NULL) {
210		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
211		return ENOBUFS;
212	}
213#ifndef __NO_STRICT_ALIGNMENT
214	if (family == AF_LINK) {
215		len = mtod(m, vm_offset_t) & 3;
216		KASSERT(len == 0 || len == ETHERIP_ALIGN,
217		    ("in_gif_output: unexpected misalignment"));
218		m->m_data += len;
219		m->m_len -= ETHERIP_ALIGN;
220	}
221#endif
222	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
223
224	M_SETFIB(m, sc->gif_fibnum);
225
226	if (dst->sin_family != sin_dst->sin_family ||
227	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
228		/* cache route doesn't match */
229		bzero(dst, sizeof(*dst));
230		dst->sin_family = sin_dst->sin_family;
231		dst->sin_len = sizeof(struct sockaddr_in);
232		dst->sin_addr = sin_dst->sin_addr;
233		if (sc->gif_ro.ro_rt) {
234			RTFREE(sc->gif_ro.ro_rt);
235			sc->gif_ro.ro_rt = NULL;
236		}
237#if 0
238		GIF2IFP(sc)->if_mtu = GIF_MTU;
239#endif
240	}
241
242	if (sc->gif_ro.ro_rt == NULL) {
243		in_rtalloc_ign(&sc->gif_ro, 0, sc->gif_fibnum);
244		if (sc->gif_ro.ro_rt == NULL) {
245			m_freem(m);
246			return ENETUNREACH;
247		}
248
249		/* if it constitutes infinite encapsulation, punt. */
250		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
251			m_freem(m);
252			return ENETUNREACH;	/* XXX */
253		}
254#if 0
255		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
256			- sizeof(struct ip);
257#endif
258	}
259
260	m->m_flags &= ~(M_BCAST|M_MCAST);
261	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
262
263	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
264	    sc->gif_ro.ro_rt != NULL) {
265		RTFREE(sc->gif_ro.ro_rt);
266		sc->gif_ro.ro_rt = NULL;
267	}
268
269	return (error);
270}
271
272void
273in_gif_input(struct mbuf *m, int off)
274{
275	struct ifnet *gifp = NULL;
276	struct gif_softc *sc;
277	struct ip *ip;
278	int af;
279	u_int8_t otos;
280	int proto;
281
282	ip = mtod(m, struct ip *);
283	proto = ip->ip_p;
284
285	sc = (struct gif_softc *)encap_getarg(m);
286	if (sc == NULL) {
287		m_freem(m);
288		KMOD_IPSTAT_INC(ips_nogif);
289		return;
290	}
291
292	gifp = GIF2IFP(sc);
293	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
294		m_freem(m);
295		KMOD_IPSTAT_INC(ips_nogif);
296		return;
297	}
298
299	otos = ip->ip_tos;
300	m_adj(m, off);
301
302	switch (proto) {
303#ifdef INET
304	case IPPROTO_IPV4:
305	    {
306		struct ip *ip;
307		af = AF_INET;
308		if (m->m_len < sizeof(*ip)) {
309			m = m_pullup(m, sizeof(*ip));
310			if (!m)
311				return;
312		}
313		ip = mtod(m, struct ip *);
314		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
315				  ECN_ALLOWED : ECN_NOCARE,
316				  &otos, &ip->ip_tos) == 0) {
317			m_freem(m);
318			return;
319		}
320		break;
321	    }
322#endif
323#ifdef INET6
324	case IPPROTO_IPV6:
325	    {
326		struct ip6_hdr *ip6;
327		u_int8_t itos, oitos;
328
329		af = AF_INET6;
330		if (m->m_len < sizeof(*ip6)) {
331			m = m_pullup(m, sizeof(*ip6));
332			if (!m)
333				return;
334		}
335		ip6 = mtod(m, struct ip6_hdr *);
336		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
337		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
338				  ECN_ALLOWED : ECN_NOCARE,
339				  &otos, &itos) == 0) {
340			m_freem(m);
341			return;
342		}
343		if (itos != oitos) {
344			ip6->ip6_flow &= ~htonl(0xff << 20);
345			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
346		}
347		break;
348	    }
349#endif /* INET6 */
350 	case IPPROTO_ETHERIP:
351 		af = AF_LINK;
352 		break;
353
354	default:
355		KMOD_IPSTAT_INC(ips_nogif);
356		m_freem(m);
357		return;
358	}
359	gif_input(m, af, gifp);
360	return;
361}
362
363/*
364 * validate outer address.
365 */
366static int
367gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
368{
369	struct sockaddr_in *src, *dst;
370	struct in_ifaddr *ia4;
371
372	src = (struct sockaddr_in *)sc->gif_psrc;
373	dst = (struct sockaddr_in *)sc->gif_pdst;
374
375	/* check for address match */
376	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
377	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
378		return 0;
379
380	/* martian filters on outer source - NOT done in ip_input! */
381	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
382		return 0;
383	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
384	case 0: case 127: case 255:
385		return 0;
386	}
387
388	/* reject packets with broadcast on source */
389	/* XXXRW: should use hash lists? */
390	IN_IFADDR_RLOCK();
391	TAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
392		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
393			continue;
394		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
395			IN_IFADDR_RUNLOCK();
396			return 0;
397		}
398	}
399	IN_IFADDR_RUNLOCK();
400
401	/* ingress filters on outer source */
402	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
403		struct sockaddr_in sin;
404		struct rtentry *rt;
405
406		bzero(&sin, sizeof(sin));
407		sin.sin_family = AF_INET;
408		sin.sin_len = sizeof(struct sockaddr_in);
409		sin.sin_addr = ip->ip_src;
410		/* XXX MRT  check for the interface we would use on output */
411		rt = in_rtalloc1((struct sockaddr *)&sin, 0,
412		    0UL, sc->gif_fibnum);
413		if (!rt || rt->rt_ifp != ifp) {
414#if 0
415			log(LOG_WARNING, "%s: packet from 0x%x dropped "
416			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
417			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
418#endif
419			if (rt)
420				RTFREE_LOCKED(rt);
421			return 0;
422		}
423		RTFREE_LOCKED(rt);
424	}
425
426	return 32 * 2;
427}
428
429/*
430 * we know that we are in IFF_UP, outer address available, and outer family
431 * matched the physical addr family.  see gif_encapcheck().
432 */
433int
434gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
435{
436	struct ip ip;
437	struct gif_softc *sc;
438	struct ifnet *ifp;
439
440	/* sanity check done in caller */
441	sc = (struct gif_softc *)arg;
442
443	/* LINTED const cast */
444	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
445	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
446
447	return gif_validate4(&ip, sc, ifp);
448}
449
450int
451in_gif_attach(struct gif_softc *sc)
452{
453	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
454	    &in_gif_protosw, sc);
455	if (sc->encap_cookie4 == NULL)
456		return EEXIST;
457	return 0;
458}
459
460int
461in_gif_detach(struct gif_softc *sc)
462{
463	int error;
464
465	error = encap_detach(sc->encap_cookie4);
466	if (error == 0)
467		sc->encap_cookie4 = NULL;
468	return error;
469}
470