in6_gif.c revision 269054 
1/*-
2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the project nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30 */
31
32#include <sys/cdefs.h>
33__FBSDID("$FreeBSD: head/sys/netinet6/in6_gif.c 269054 2014-07-24 10:42:47Z hrs $");
34
35#include "opt_inet.h"
36#include "opt_inet6.h"
37
38#include <sys/param.h>
39#include <sys/systm.h>
40#include <sys/socket.h>
41#include <sys/sockio.h>
42#include <sys/mbuf.h>
43#include <sys/errno.h>
44#include <sys/kernel.h>
45#include <sys/queue.h>
46#include <sys/syslog.h>
47#include <sys/sysctl.h>
48#include <sys/protosw.h>
49#include <sys/malloc.h>
50
51#include <net/if.h>
52#include <net/if_var.h>
53#include <net/route.h>
54#include <net/vnet.h>
55
56#include <netinet/in.h>
57#include <netinet/in_systm.h>
58#ifdef INET
59#include <netinet/ip.h>
60#endif
61#include <netinet/ip_encap.h>
62#ifdef INET6
63#include <netinet/ip6.h>
64#include <netinet6/ip6_var.h>
65#include <netinet6/in6_gif.h>
66#include <netinet6/in6_var.h>
67#endif
68#include <netinet6/ip6protosw.h>
69#include <netinet/ip_ecn.h>
70#ifdef INET6
71#include <netinet6/ip6_ecn.h>
72#endif
73
74#include <net/if_gif.h>
75
76VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
77#define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
78
79SYSCTL_DECL(_net_inet6_ip6);
80SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
81    &VNET_NAME(ip6_gif_hlim), 0, "");
82
83static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
84			 struct ifnet *);
85
86extern  struct domain inet6domain;
87struct ip6protosw in6_gif_protosw = {
88	.pr_type =	SOCK_RAW,
89	.pr_domain =	&inet6domain,
90	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
91	.pr_flags =	PR_ATOMIC|PR_ADDR,
92	.pr_input =	in6_gif_input,
93	.pr_output =	rip6_output,
94	.pr_ctloutput =	rip6_ctloutput,
95	.pr_usrreqs =	&rip6_usrreqs
96};
97
98int
99in6_gif_output(struct ifnet *ifp,
100    int family,			/* family of the packet to be encapsulate */
101    struct mbuf *m)
102{
103	struct gif_softc *sc = ifp->if_softc;
104	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
105	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
106	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
107	struct ip6_hdr *ip6;
108	struct etherip_header eiphdr;
109	int error, len, proto;
110	u_int8_t itos, otos;
111
112	GIF_LOCK_ASSERT(sc);
113
114	if (sin6_src == NULL || sin6_dst == NULL ||
115	    sin6_src->sin6_family != AF_INET6 ||
116	    sin6_dst->sin6_family != AF_INET6) {
117		m_freem(m);
118		return EAFNOSUPPORT;
119	}
120
121	switch (family) {
122#ifdef INET
123	case AF_INET:
124	    {
125		struct ip *ip;
126
127		proto = IPPROTO_IPV4;
128		if (m->m_len < sizeof(*ip)) {
129			m = m_pullup(m, sizeof(*ip));
130			if (!m)
131				return ENOBUFS;
132		}
133		ip = mtod(m, struct ip *);
134		itos = ip->ip_tos;
135		break;
136	    }
137#endif
138#ifdef INET6
139	case AF_INET6:
140	    {
141		struct ip6_hdr *ip6;
142		proto = IPPROTO_IPV6;
143		if (m->m_len < sizeof(*ip6)) {
144			m = m_pullup(m, sizeof(*ip6));
145			if (!m)
146				return ENOBUFS;
147		}
148		ip6 = mtod(m, struct ip6_hdr *);
149		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
150		break;
151	    }
152#endif
153	case AF_LINK:
154		proto = IPPROTO_ETHERIP;
155
156		/*
157		 * GIF_SEND_REVETHIP (disabled by default) intentionally
158		 * sends an EtherIP packet with revered version field in
159		 * the header.  This is a knob for backward compatibility
160		 * with FreeBSD 7.2R or prior.
161		 */
162		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
163			eiphdr.eip_ver = 0;
164			eiphdr.eip_resvl = ETHERIP_VERSION;
165			eiphdr.eip_resvh = 0;
166		} else {
167			eiphdr.eip_ver = ETHERIP_VERSION;
168			eiphdr.eip_resvl = 0;
169			eiphdr.eip_resvh = 0;
170		}
171		/* prepend Ethernet-in-IP header */
172		M_PREPEND(m, sizeof(struct etherip_header), M_NOWAIT);
173		if (m && m->m_len < sizeof(struct etherip_header))
174			m = m_pullup(m, sizeof(struct etherip_header));
175		if (m == NULL)
176			return ENOBUFS;
177		bcopy(&eiphdr, mtod(m, struct etherip_header *),
178		    sizeof(struct etherip_header));
179		itos = 0;
180		break;
181
182	default:
183#ifdef DEBUG
184		printf("in6_gif_output: warning: unknown family %d passed\n",
185			family);
186#endif
187		m_freem(m);
188		return EAFNOSUPPORT;
189	}
190
191	/* prepend new IP header */
192	len = sizeof(struct ip6_hdr);
193#ifndef __NO_STRICT_ALIGNMENT
194	if (family == AF_LINK)
195		len += ETHERIP_ALIGN;
196#endif
197	M_PREPEND(m, len, M_NOWAIT);
198	if (m != NULL && m->m_len < len)
199		m = m_pullup(m, len);
200	if (m == NULL) {
201		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
202		return ENOBUFS;
203	}
204#ifndef __NO_STRICT_ALIGNMENT
205	if (family == AF_LINK) {
206		len = mtod(m, vm_offset_t) & 3;
207		KASSERT(len == 0 || len == ETHERIP_ALIGN,
208		    ("in6_gif_output: unexpected misalignment"));
209		m->m_data += len;
210		m->m_len -= ETHERIP_ALIGN;
211	}
212#endif
213
214	ip6 = mtod(m, struct ip6_hdr *);
215	ip6->ip6_flow	= 0;
216	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
217	ip6->ip6_vfc	|= IPV6_VERSION;
218	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
219	ip6->ip6_nxt	= proto;
220	ip6->ip6_hlim	= V_ip6_gif_hlim;
221	ip6->ip6_src	= sin6_src->sin6_addr;
222	/* bidirectional configured tunnel mode */
223	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
224		ip6->ip6_dst = sin6_dst->sin6_addr;
225	else  {
226		m_freem(m);
227		return ENETUNREACH;
228	}
229	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
230		       &otos, &itos);
231	ip6->ip6_flow &= ~htonl(0xff << 20);
232	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
233
234	M_SETFIB(m, sc->gif_fibnum);
235
236	if (dst->sin6_family != sin6_dst->sin6_family ||
237	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
238		/* cache route doesn't match */
239		bzero(dst, sizeof(*dst));
240		dst->sin6_family = sin6_dst->sin6_family;
241		dst->sin6_len = sizeof(struct sockaddr_in6);
242		dst->sin6_addr = sin6_dst->sin6_addr;
243		if (sc->gif_ro6.ro_rt) {
244			RTFREE(sc->gif_ro6.ro_rt);
245			sc->gif_ro6.ro_rt = NULL;
246		}
247#if 0
248		GIF2IFP(sc)->if_mtu = GIF_MTU;
249#endif
250	}
251
252	if (sc->gif_ro6.ro_rt == NULL) {
253		in6_rtalloc(&sc->gif_ro6, sc->gif_fibnum);
254		if (sc->gif_ro6.ro_rt == NULL) {
255			m_freem(m);
256			return ENETUNREACH;
257		}
258
259		/* if it constitutes infinite encapsulation, punt. */
260		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
261			m_freem(m);
262			return ENETUNREACH;	/*XXX*/
263		}
264#if 0
265		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
266			- sizeof(struct ip6_hdr);
267#endif
268	}
269
270	m->m_flags &= ~(M_BCAST|M_MCAST);
271#ifdef IPV6_MINMTU
272	/*
273	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
274	 * it is too painful to ask for resend of inner packet, to achieve
275	 * path MTU discovery for encapsulated packets.
276	 */
277	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
278#else
279	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
280#endif
281
282	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
283	    sc->gif_ro6.ro_rt != NULL) {
284		RTFREE(sc->gif_ro6.ro_rt);
285		sc->gif_ro6.ro_rt = NULL;
286	}
287
288	return (error);
289}
290
291int
292in6_gif_input(struct mbuf **mp, int *offp, int proto)
293{
294	struct mbuf *m = *mp;
295	struct ifnet *gifp = NULL;
296	struct gif_softc *sc;
297	struct ip6_hdr *ip6;
298	int af = 0;
299	u_int32_t otos;
300
301	ip6 = mtod(m, struct ip6_hdr *);
302
303	sc = (struct gif_softc *)encap_getarg(m);
304	if (sc == NULL) {
305		m_freem(m);
306		IP6STAT_INC(ip6s_nogif);
307		return IPPROTO_DONE;
308	}
309
310	gifp = GIF2IFP(sc);
311	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
312		m_freem(m);
313		IP6STAT_INC(ip6s_nogif);
314		return IPPROTO_DONE;
315	}
316
317	otos = ip6->ip6_flow;
318	m_adj(m, *offp);
319
320	switch (proto) {
321#ifdef INET
322	case IPPROTO_IPV4:
323	    {
324		struct ip *ip;
325		u_int8_t otos8;
326		af = AF_INET;
327		otos8 = (ntohl(otos) >> 20) & 0xff;
328		if (m->m_len < sizeof(*ip)) {
329			m = m_pullup(m, sizeof(*ip));
330			if (!m)
331				return IPPROTO_DONE;
332		}
333		ip = mtod(m, struct ip *);
334		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
335				  ECN_ALLOWED : ECN_NOCARE,
336				  &otos8, &ip->ip_tos) == 0) {
337			m_freem(m);
338			return IPPROTO_DONE;
339		}
340		break;
341	    }
342#endif /* INET */
343#ifdef INET6
344	case IPPROTO_IPV6:
345	    {
346		struct ip6_hdr *ip6;
347		af = AF_INET6;
348		if (m->m_len < sizeof(*ip6)) {
349			m = m_pullup(m, sizeof(*ip6));
350			if (!m)
351				return IPPROTO_DONE;
352		}
353		ip6 = mtod(m, struct ip6_hdr *);
354		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
355				   ECN_ALLOWED : ECN_NOCARE,
356				   &otos, &ip6->ip6_flow) == 0) {
357			m_freem(m);
358			return IPPROTO_DONE;
359		}
360		break;
361	    }
362#endif
363	case IPPROTO_ETHERIP:
364		af = AF_LINK;
365		break;
366
367	default:
368		IP6STAT_INC(ip6s_nogif);
369		m_freem(m);
370		return IPPROTO_DONE;
371	}
372
373	gif_input(m, af, gifp);
374	return IPPROTO_DONE;
375}
376
377/*
378 * validate outer address.
379 */
380static int
381gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
382    struct ifnet *ifp)
383{
384	struct sockaddr_in6 *src, *dst;
385
386	src = (struct sockaddr_in6 *)sc->gif_psrc;
387	dst = (struct sockaddr_in6 *)sc->gif_pdst;
388
389	/*
390	 * Check for address match.  Note that the check is for an incoming
391	 * packet.  We should compare the *source* address in our configuration
392	 * and the *destination* address of the packet, and vice versa.
393	 */
394	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
395	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
396		return 0;
397
398	/* martian filters on outer source - done in ip6_input */
399
400	/* ingress filters on outer source */
401	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
402		struct sockaddr_in6 sin6;
403		struct rtentry *rt;
404
405		bzero(&sin6, sizeof(sin6));
406		sin6.sin6_family = AF_INET6;
407		sin6.sin6_len = sizeof(struct sockaddr_in6);
408		sin6.sin6_addr = ip6->ip6_src;
409		sin6.sin6_scope_id = 0; /* XXX */
410
411		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
412		    sc->gif_fibnum);
413		if (!rt || rt->rt_ifp != ifp) {
414#if 0
415			char ip6buf[INET6_ADDRSTRLEN];
416			log(LOG_WARNING, "%s: packet from %s dropped "
417			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
418			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
419#endif
420			if (rt)
421				RTFREE_LOCKED(rt);
422			return 0;
423		}
424		RTFREE_LOCKED(rt);
425	}
426
427	return 128 * 2;
428}
429
430/*
431 * we know that we are in IFF_UP, outer address available, and outer family
432 * matched the physical addr family.  see gif_encapcheck().
433 * sanity check for arg should have been done in the caller.
434 */
435int
436gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
437{
438	struct ip6_hdr ip6;
439	struct gif_softc *sc;
440	struct ifnet *ifp;
441
442	/* sanity check done in caller */
443	sc = (struct gif_softc *)arg;
444
445	/* LINTED const cast */
446	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
447	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
448
449	return gif_validate6(&ip6, sc, ifp);
450}
451
452int
453in6_gif_attach(struct gif_softc *sc)
454{
455	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
456	    (void *)&in6_gif_protosw, sc);
457	if (sc->encap_cookie6 == NULL)
458		return EEXIST;
459	return 0;
460}
461
462int
463in6_gif_detach(struct gif_softc *sc)
464{
465	int error;
466
467	error = encap_detach(sc->encap_cookie6);
468	if (error == 0)
469		sc->encap_cookie6 = NULL;
470	return error;
471}
472