1/*
2 * Copyright (c) 2009-2013 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28
29/* $FreeBSD: src/sys/netinet6/in6_gif.c,v 1.2.2.3 2001/07/03 11:01:52 ume Exp $ */
30/* $KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $ */
31
32/*
33 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
34 * All rights reserved.
35 *
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
38 * are met:
39 * 1. Redistributions of source code must retain the above copyright
40 *    notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 *    notice, this list of conditions and the following disclaimer in the
43 *    documentation and/or other materials provided with the distribution.
44 * 3. Neither the name of the project nor the names of its contributors
45 *    may be used to endorse or promote products derived from this software
46 *    without specific prior written permission.
47 *
48 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58 * SUCH DAMAGE.
59 */
60
61
62#include <sys/param.h>
63#include <sys/systm.h>
64#include <sys/socket.h>
65#include <sys/sockio.h>
66#include <sys/mbuf.h>
67#include <sys/errno.h>
68#include <sys/queue.h>
69#include <sys/syslog.h>
70
71#include <sys/malloc.h>
72#include <sys/protosw.h>
73
74#include <net/if.h>
75#include <net/route.h>
76
77#include <netinet/in.h>
78#include <netinet/in_systm.h>
79#if INET
80#include <netinet/ip.h>
81#endif
82#include <netinet/ip_encap.h>
83#if INET6
84#include <netinet/ip6.h>
85#include <netinet6/ip6_var.h>
86#include <netinet6/in6_gif.h>
87#include <netinet6/in6_var.h>
88#endif
89#include <netinet/ip_ecn.h>
90#if INET6
91#include <netinet6/ip6_ecn.h>
92#endif
93
94#include <net/if_gif.h>
95
96#include <net/net_osdep.h>
97
98int
99in6_gif_output(
100	struct ifnet *ifp,
101	int family, /* family of the packet to be encapsulate. */
102	struct mbuf *m,
103	__unused struct rtentry *rt)
104{
105	struct gif_softc *sc = ifnet_softc(ifp);
106	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
107	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)
108	    (void *)sc->gif_psrc;
109	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)
110	    (void *)sc->gif_pdst;
111	struct ip6_hdr *ip6;
112	int proto;
113	u_int8_t itos, otos;
114
115	GIF_LOCK_ASSERT(sc);
116
117	if (sin6_src == NULL || sin6_dst == NULL ||
118	    sin6_src->sin6_family != AF_INET6 ||
119	    sin6_dst->sin6_family != AF_INET6) {
120		m_freem(m);
121		return (EAFNOSUPPORT);
122	}
123
124	switch (family) {
125#if INET
126	case AF_INET:
127	    {
128		struct ip *ip;
129
130		proto = IPPROTO_IPV4;
131		if (mbuf_len(m) < sizeof (*ip)) {
132			m = m_pullup(m, sizeof (*ip));
133			if (!m)
134				return (ENOBUFS);
135		}
136		ip = mtod(m, struct ip *);
137		itos = ip->ip_tos;
138		break;
139	    }
140#endif
141#if INET6
142	case AF_INET6:
143	    {
144		proto = IPPROTO_IPV6;
145		if (mbuf_len(m) < sizeof (*ip6)) {
146			m = m_pullup(m, sizeof (*ip6));
147			if (!m)
148				return (ENOBUFS);
149		}
150		ip6 = mtod(m, struct ip6_hdr *);
151		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
152		break;
153	    }
154#endif
155	default:
156#if DEBUG
157		printf("in6_gif_output: warning: unknown family %d passed\n",
158			family);
159#endif
160		m_freem(m);
161		return (EAFNOSUPPORT);
162	}
163
164	/* prepend new IP header */
165	M_PREPEND(m, sizeof (struct ip6_hdr), M_DONTWAIT);
166	if (m && mbuf_len(m) < sizeof (struct ip6_hdr))
167		m = m_pullup(m, sizeof (struct ip6_hdr));
168	if (m == NULL) {
169		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
170		return (ENOBUFS);
171	}
172
173	ip6 = mtod(m, struct ip6_hdr *);
174	ip6->ip6_flow	= 0;
175	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
176	ip6->ip6_vfc	|= IPV6_VERSION;
177	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
178	ip6->ip6_nxt	= proto;
179	ip6->ip6_hlim	= ip6_gif_hlim;
180	ip6->ip6_src	= sin6_src->sin6_addr;
181	/* bidirectional configured tunnel mode */
182	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
183		ip6->ip6_dst = sin6_dst->sin6_addr;
184	else  {
185		m_freem(m);
186		return (ENETUNREACH);
187	}
188	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
189	    &otos, &itos);
190	ip6->ip6_flow &= ~htonl(0xff << 20);
191	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
192
193	if (ROUTE_UNUSABLE(&sc->gif_ro6) ||
194	    dst->sin6_family != sin6_dst->sin6_family ||
195	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr) ||
196	    (sc->gif_ro6.ro_rt != NULL && sc->gif_ro6.ro_rt->rt_ifp == ifp)) {
197		/* cache route doesn't match or recursive route */
198		bzero(dst, sizeof (*dst));
199		dst->sin6_family = sin6_dst->sin6_family;
200		dst->sin6_len = sizeof (struct sockaddr_in6);
201		dst->sin6_addr = sin6_dst->sin6_addr;
202		ROUTE_RELEASE(&sc->gif_ro6);
203#if 0
204		sc->gif_if.if_mtu = GIF_MTU;
205#endif
206	}
207
208	if (sc->gif_ro6.ro_rt == NULL) {
209		rtalloc((struct route *)&sc->gif_ro6);
210		if (sc->gif_ro6.ro_rt == NULL) {
211			m_freem(m);
212			return (ENETUNREACH);
213		}
214		RT_LOCK(sc->gif_ro6.ro_rt);
215		/* if it constitutes infinite encapsulation, punt. */
216		if (sc->gif_ro6.ro_rt->rt_ifp == ifp) {
217			RT_UNLOCK(sc->gif_ro6.ro_rt);
218			m_freem(m);
219			return (ENETUNREACH); /* XXX */
220		}
221#if 0
222		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
223			- sizeof (struct ip6_hdr);
224#endif
225		RT_UNLOCK(sc->gif_ro6.ro_rt);
226	}
227
228#if IPV6_MINMTU
229	/*
230	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
231	 * it is too painful to ask for resend of inner packet, to achieve
232	 * path MTU discovery for encapsulated packets.
233	 */
234	return (ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL));
235#else
236	return (ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL));
237#endif
238}
239
240int
241in6_gif_input(struct mbuf **mp, int *offp, int proto)
242{
243	struct mbuf *m = *mp;
244	struct ifnet *gifp = NULL;
245	struct ip6_hdr *ip6;
246	int af = 0;
247	u_int32_t otos;
248
249	ip6 = mtod(m, struct ip6_hdr *);
250
251	gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
252
253	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
254		m_freem(m);
255		ip6stat.ip6s_nogif++;
256		return (IPPROTO_DONE);
257	}
258
259	otos = ip6->ip6_flow;
260	m_adj(m, *offp);
261
262	switch (proto) {
263#if INET
264	case IPPROTO_IPV4:
265	    {
266		struct ip *ip;
267		u_int8_t otos8;
268		af = AF_INET;
269		otos8 = (ntohl(otos) >> 20) & 0xff;
270		if (mbuf_len(m) < sizeof (*ip)) {
271			m = m_pullup(m, sizeof (*ip));
272			if (!m)
273				return (IPPROTO_DONE);
274		}
275		ip = mtod(m, struct ip *);
276		if (gifp->if_flags & IFF_LINK1)
277			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
278		else
279			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
280		break;
281	    }
282#endif /* INET */
283#if INET6
284	case IPPROTO_IPV6:
285	    {
286		af = AF_INET6;
287		if (mbuf_len(m) < sizeof (*ip6)) {
288			m = m_pullup(m, sizeof (*ip6));
289			if (!m)
290				return (IPPROTO_DONE);
291		}
292		ip6 = mtod(m, struct ip6_hdr *);
293		if (gifp->if_flags & IFF_LINK1)
294			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
295		else
296			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
297		break;
298	    }
299#endif
300	default:
301		ip6stat.ip6s_nogif++;
302		m_freem(m);
303		return (IPPROTO_DONE);
304	}
305
306	/* Replace the rcvif by gifp for ifnet_input to route it correctly */
307	if (m->m_pkthdr.rcvif)
308		m->m_pkthdr.rcvif = gifp;
309
310	ifnet_input(gifp, m, NULL);
311	return (IPPROTO_DONE);
312}
313
314/*
315 * validate outer address.
316 */
317static int
318gif_validate6(
319	const struct ip6_hdr *ip6,
320	struct gif_softc *sc,
321	struct ifnet *ifp)
322{
323	struct sockaddr_in6 *src, *dst;
324
325	src = (struct sockaddr_in6 *)(void *)sc->gif_psrc;
326	dst = (struct sockaddr_in6 *)(void *)sc->gif_pdst;
327
328	/*
329	 * Check for address match.  Note that the check is for an incoming
330	 * packet.  We should compare the *source* address in our configuration
331	 * and the *destination* address of the packet, and vice versa.
332	 */
333	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
334	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
335		return (0);
336
337	/* martian filters on outer source - done in ip6_input */
338
339	/* ingress filters on outer source */
340	if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 && ifp) {
341		struct sockaddr_in6 sin6;
342		struct rtentry *rt;
343
344		bzero(&sin6, sizeof (sin6));
345		sin6.sin6_family = AF_INET6;
346		sin6.sin6_len = sizeof (struct sockaddr_in6);
347		sin6.sin6_addr = ip6->ip6_src;
348
349		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);
350		if (rt != NULL)
351			RT_LOCK(rt);
352		if (!rt || rt->rt_ifp != ifp) {
353#if 0
354			log(LOG_WARNING, "%s: packet from %s dropped "
355			    "due to ingress filter\n", if_name(&sc->gif_if),
356			    ip6_sprintf(&sin6.sin6_addr));
357#endif
358			if (rt != NULL) {
359				RT_UNLOCK(rt);
360				rtfree(rt);
361			}
362			return (0);
363		}
364		RT_UNLOCK(rt);
365		rtfree(rt);
366	}
367
368	return (128 * 2);
369}
370
371/*
372 * we know that we are in IFF_UP, outer address available, and outer family
373 * matched the physical addr family.  see gif_encapcheck().
374 * sanity check for arg should have been done in the caller.
375 */
376int
377gif_encapcheck6(
378	const struct mbuf *m,
379	__unused int off,
380	__unused int proto,
381	void *arg)
382{
383	struct ip6_hdr ip6;
384	struct gif_softc *sc;
385	struct ifnet *ifp;
386
387	/* sanity check done in caller */
388	sc = (struct gif_softc *)arg;
389
390	GIF_LOCK_ASSERT(sc);
391
392	mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof (ip6), &ip6);
393	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
394
395	return (gif_validate6(&ip6, sc, ifp));
396}
397