in6_gif.c revision 195699 
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 195699 2009-07-14 22:48:30Z rwatson $");
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/queue.h>
45#include <sys/syslog.h>
46#include <sys/protosw.h>
47#include <sys/malloc.h>
48#include <sys/vimage.h>
49
50#include <net/if.h>
51#include <net/route.h>
52
53#include <netinet/in.h>
54#include <netinet/in_systm.h>
55#ifdef INET
56#include <netinet/ip.h>
57#endif
58#include <netinet/ip_encap.h>
59#ifdef INET6
60#include <netinet/ip6.h>
61#include <netinet6/ip6_var.h>
62#include <netinet6/in6_gif.h>
63#include <netinet6/in6_var.h>
64#endif
65#include <netinet6/ip6protosw.h>
66#include <netinet/ip_ecn.h>
67#ifdef INET6
68#include <netinet6/ip6_ecn.h>
69#endif
70
71#include <net/if_gif.h>
72
73static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
74			 struct ifnet *);
75
76extern  struct domain inet6domain;
77struct ip6protosw in6_gif_protosw = {
78	.pr_type =	SOCK_RAW,
79	.pr_domain =	&inet6domain,
80	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
81	.pr_flags =	PR_ATOMIC|PR_ADDR,
82	.pr_input =	in6_gif_input,
83	.pr_output =	rip6_output,
84	.pr_ctloutput =	rip6_ctloutput,
85	.pr_usrreqs =	&rip6_usrreqs
86};
87
88int
89in6_gif_output(struct ifnet *ifp,
90    int family,			/* family of the packet to be encapsulate */
91    struct mbuf *m)
92{
93	struct gif_softc *sc = ifp->if_softc;
94	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
95	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
96	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
97	struct ip6_hdr *ip6;
98	struct etherip_header eiphdr;
99	int error, len, proto;
100	u_int8_t itos, otos;
101
102	GIF_LOCK_ASSERT(sc);
103
104	if (sin6_src == NULL || sin6_dst == NULL ||
105	    sin6_src->sin6_family != AF_INET6 ||
106	    sin6_dst->sin6_family != AF_INET6) {
107		m_freem(m);
108		return EAFNOSUPPORT;
109	}
110
111	switch (family) {
112#ifdef INET
113	case AF_INET:
114	    {
115		struct ip *ip;
116
117		proto = IPPROTO_IPV4;
118		if (m->m_len < sizeof(*ip)) {
119			m = m_pullup(m, sizeof(*ip));
120			if (!m)
121				return ENOBUFS;
122		}
123		ip = mtod(m, struct ip *);
124		itos = ip->ip_tos;
125		break;
126	    }
127#endif
128#ifdef INET6
129	case AF_INET6:
130	    {
131		struct ip6_hdr *ip6;
132		proto = IPPROTO_IPV6;
133		if (m->m_len < sizeof(*ip6)) {
134			m = m_pullup(m, sizeof(*ip6));
135			if (!m)
136				return ENOBUFS;
137		}
138		ip6 = mtod(m, struct ip6_hdr *);
139		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
140		break;
141	    }
142#endif
143	case AF_LINK:
144		proto = IPPROTO_ETHERIP;
145
146		/*
147		 * GIF_SEND_REVETHIP (disabled by default) intentionally
148		 * sends an EtherIP packet with revered version field in
149		 * the header.  This is a knob for backward compatibility
150		 * with FreeBSD 7.2R or prior.
151		 */
152		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
153			eiphdr.eip_ver = 0;
154			eiphdr.eip_resvl = ETHERIP_VERSION;
155			eiphdr.eip_resvh = 0;
156		} else {
157			eiphdr.eip_ver = ETHERIP_VERSION;
158			eiphdr.eip_resvl = 0;
159			eiphdr.eip_resvh = 0;
160		}
161		/* prepend Ethernet-in-IP header */
162		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
163		if (m && m->m_len < sizeof(struct etherip_header))
164			m = m_pullup(m, sizeof(struct etherip_header));
165		if (m == NULL)
166			return ENOBUFS;
167		bcopy(&eiphdr, mtod(m, struct etherip_header *),
168		    sizeof(struct etherip_header));
169		break;
170
171	default:
172#ifdef DEBUG
173		printf("in6_gif_output: warning: unknown family %d passed\n",
174			family);
175#endif
176		m_freem(m);
177		return EAFNOSUPPORT;
178	}
179
180	/* prepend new IP header */
181	len = sizeof(struct ip6_hdr);
182#ifndef __NO_STRICT_ALIGNMENT
183	if (family == AF_LINK)
184		len += ETHERIP_ALIGN;
185#endif
186	M_PREPEND(m, len, M_DONTWAIT);
187	if (m != NULL && m->m_len < len)
188		m = m_pullup(m, len);
189	if (m == NULL) {
190		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
191		return ENOBUFS;
192	}
193#ifndef __NO_STRICT_ALIGNMENT
194	if (family == AF_LINK) {
195		len = mtod(m, vm_offset_t) & 3;
196		KASSERT(len == 0 || len == ETHERIP_ALIGN,
197		    ("in6_gif_output: unexpected misalignment"));
198		m->m_data += len;
199		m->m_len -= ETHERIP_ALIGN;
200	}
201#endif
202
203	ip6 = mtod(m, struct ip6_hdr *);
204	ip6->ip6_flow	= 0;
205	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
206	ip6->ip6_vfc	|= IPV6_VERSION;
207	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
208	ip6->ip6_nxt	= proto;
209	ip6->ip6_hlim	= V_ip6_gif_hlim;
210	ip6->ip6_src	= sin6_src->sin6_addr;
211	/* bidirectional configured tunnel mode */
212	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
213		ip6->ip6_dst = sin6_dst->sin6_addr;
214	else  {
215		m_freem(m);
216		return ENETUNREACH;
217	}
218	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
219		       &otos, &itos);
220	ip6->ip6_flow &= ~htonl(0xff << 20);
221	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
222
223	if (dst->sin6_family != sin6_dst->sin6_family ||
224	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
225		/* cache route doesn't match */
226		bzero(dst, sizeof(*dst));
227		dst->sin6_family = sin6_dst->sin6_family;
228		dst->sin6_len = sizeof(struct sockaddr_in6);
229		dst->sin6_addr = sin6_dst->sin6_addr;
230		if (sc->gif_ro6.ro_rt) {
231			RTFREE(sc->gif_ro6.ro_rt);
232			sc->gif_ro6.ro_rt = NULL;
233		}
234#if 0
235		GIF2IFP(sc)->if_mtu = GIF_MTU;
236#endif
237	}
238
239	if (sc->gif_ro6.ro_rt == NULL) {
240		rtalloc((struct route *)&sc->gif_ro6);
241		if (sc->gif_ro6.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_ro6.ro_rt->rt_ifp->if_mtu
253			- sizeof(struct ip6_hdr);
254#endif
255	}
256
257#ifdef IPV6_MINMTU
258	/*
259	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
260	 * it is too painful to ask for resend of inner packet, to achieve
261	 * path MTU discovery for encapsulated packets.
262	 */
263	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
264#else
265	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
266#endif
267
268	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
269	    sc->gif_ro6.ro_rt != NULL) {
270		RTFREE(sc->gif_ro6.ro_rt);
271		sc->gif_ro6.ro_rt = NULL;
272	}
273
274	return (error);
275}
276
277int
278in6_gif_input(struct mbuf **mp, int *offp, int proto)
279{
280	struct mbuf *m = *mp;
281	struct ifnet *gifp = NULL;
282	struct gif_softc *sc;
283	struct ip6_hdr *ip6;
284	int af = 0;
285	u_int32_t otos;
286
287	ip6 = mtod(m, struct ip6_hdr *);
288
289	sc = (struct gif_softc *)encap_getarg(m);
290	if (sc == NULL) {
291		m_freem(m);
292		V_ip6stat.ip6s_nogif++;
293		return IPPROTO_DONE;
294	}
295
296	gifp = GIF2IFP(sc);
297	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
298		m_freem(m);
299		V_ip6stat.ip6s_nogif++;
300		return IPPROTO_DONE;
301	}
302
303	otos = ip6->ip6_flow;
304	m_adj(m, *offp);
305
306	switch (proto) {
307#ifdef INET
308	case IPPROTO_IPV4:
309	    {
310		struct ip *ip;
311		u_int8_t otos8;
312		af = AF_INET;
313		otos8 = (ntohl(otos) >> 20) & 0xff;
314		if (m->m_len < sizeof(*ip)) {
315			m = m_pullup(m, sizeof(*ip));
316			if (!m)
317				return IPPROTO_DONE;
318		}
319		ip = mtod(m, struct ip *);
320		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
321				  ECN_ALLOWED : ECN_NOCARE,
322				  &otos8, &ip->ip_tos) == 0) {
323			m_freem(m);
324			return IPPROTO_DONE;
325		}
326		break;
327	    }
328#endif /* INET */
329#ifdef INET6
330	case IPPROTO_IPV6:
331	    {
332		struct ip6_hdr *ip6;
333		af = AF_INET6;
334		if (m->m_len < sizeof(*ip6)) {
335			m = m_pullup(m, sizeof(*ip6));
336			if (!m)
337				return IPPROTO_DONE;
338		}
339		ip6 = mtod(m, struct ip6_hdr *);
340		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
341				   ECN_ALLOWED : ECN_NOCARE,
342				   &otos, &ip6->ip6_flow) == 0) {
343			m_freem(m);
344			return IPPROTO_DONE;
345		}
346		break;
347	    }
348#endif
349	case IPPROTO_ETHERIP:
350		af = AF_LINK;
351		break;
352
353	default:
354		V_ip6stat.ip6s_nogif++;
355		m_freem(m);
356		return IPPROTO_DONE;
357	}
358
359	gif_input(m, af, gifp);
360	return IPPROTO_DONE;
361}
362
363/*
364 * validate outer address.
365 */
366static int
367gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
368    struct ifnet *ifp)
369{
370	struct sockaddr_in6 *src, *dst;
371
372	src = (struct sockaddr_in6 *)sc->gif_psrc;
373	dst = (struct sockaddr_in6 *)sc->gif_pdst;
374
375	/*
376	 * Check for address match.  Note that the check is for an incoming
377	 * packet.  We should compare the *source* address in our configuration
378	 * and the *destination* address of the packet, and vice versa.
379	 */
380	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
381	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
382		return 0;
383
384	/* martian filters on outer source - done in ip6_input */
385
386	/* ingress filters on outer source */
387	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
388		struct sockaddr_in6 sin6;
389		struct rtentry *rt;
390
391		bzero(&sin6, sizeof(sin6));
392		sin6.sin6_family = AF_INET6;
393		sin6.sin6_len = sizeof(struct sockaddr_in6);
394		sin6.sin6_addr = ip6->ip6_src;
395		sin6.sin6_scope_id = 0; /* XXX */
396
397		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
398		if (!rt || rt->rt_ifp != ifp) {
399#if 0
400			char ip6buf[INET6_ADDRSTRLEN];
401			log(LOG_WARNING, "%s: packet from %s dropped "
402			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
403			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
404#endif
405			if (rt)
406				RTFREE_LOCKED(rt);
407			return 0;
408		}
409		RTFREE_LOCKED(rt);
410	}
411
412	return 128 * 2;
413}
414
415/*
416 * we know that we are in IFF_UP, outer address available, and outer family
417 * matched the physical addr family.  see gif_encapcheck().
418 * sanity check for arg should have been done in the caller.
419 */
420int
421gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
422{
423	struct ip6_hdr ip6;
424	struct gif_softc *sc;
425	struct ifnet *ifp;
426
427	/* sanity check done in caller */
428	sc = (struct gif_softc *)arg;
429
430	/* LINTED const cast */
431	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
432	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
433
434	return gif_validate6(&ip6, sc, ifp);
435}
436
437int
438in6_gif_attach(struct gif_softc *sc)
439{
440	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
441	    (void *)&in6_gif_protosw, sc);
442	if (sc->encap_cookie6 == NULL)
443		return EEXIST;
444	return 0;
445}
446
447int
448in6_gif_detach(struct gif_softc *sc)
449{
450	int error;
451
452	error = encap_detach(sc->encap_cookie6);
453	if (error == 0)
454		sc->encap_cookie6 = NULL;
455	return error;
456}
457