1/*
2 * Copyright (c) 2009-2012 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
98static __inline__ void*
99_cast_non_const(const void * ptr) {
100	union {
101		const void*		cval;
102		void*			val;
103	} ret;
104
105	ret.cval = ptr;
106	return (ret.val);
107}
108
109int
110in6_gif_output(
111	struct ifnet *ifp,
112	int family, /* family of the packet to be encapsulate. */
113	struct mbuf *m,
114	__unused struct rtentry *rt)
115{
116	struct gif_softc *sc = ifnet_softc(ifp);
117	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
118	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)(void *)sc->gif_psrc;
119	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)(void *)sc->gif_pdst;
120	struct ip6_hdr *ip6;
121	int proto;
122	u_int8_t itos, otos;
123
124	if (sin6_src == NULL || sin6_dst == NULL ||
125	    sin6_src->sin6_family != AF_INET6 ||
126	    sin6_dst->sin6_family != AF_INET6) {
127		m_freem(m);
128		return EAFNOSUPPORT;
129	}
130
131	switch (family) {
132#if INET
133	case AF_INET:
134	    {
135		struct ip *ip;
136
137		proto = IPPROTO_IPV4;
138		if (mbuf_len(m) < sizeof(*ip)) {
139			m = m_pullup(m, sizeof(*ip));
140			if (!m)
141				return ENOBUFS;
142		}
143		ip = mtod(m, struct ip *);
144		itos = ip->ip_tos;
145		break;
146	    }
147#endif
148#if INET6
149	case AF_INET6:
150	    {
151		proto = IPPROTO_IPV6;
152		if (mbuf_len(m) < sizeof(*ip6)) {
153			m = m_pullup(m, sizeof(*ip6));
154			if (!m)
155				return ENOBUFS;
156		}
157		ip6 = mtod(m, struct ip6_hdr *);
158		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
159		break;
160	    }
161#endif
162	default:
163#if DEBUG
164		printf("in6_gif_output: warning: unknown family %d passed\n",
165			family);
166#endif
167		m_freem(m);
168		return EAFNOSUPPORT;
169	}
170
171	/* prepend new IP header */
172	M_PREPEND(m, sizeof(struct ip6_hdr), M_DONTWAIT);
173	if (m && mbuf_len(m) < sizeof(struct ip6_hdr))
174		m = m_pullup(m, sizeof(struct ip6_hdr));
175	if (m == NULL) {
176		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
177		return ENOBUFS;
178	}
179
180	ip6 = mtod(m, struct ip6_hdr *);
181	ip6->ip6_flow	= 0;
182	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
183	ip6->ip6_vfc	|= IPV6_VERSION;
184	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
185	ip6->ip6_nxt	= proto;
186	ip6->ip6_hlim	= ip6_gif_hlim;
187	ip6->ip6_src	= sin6_src->sin6_addr;
188	/* bidirectional configured tunnel mode */
189	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
190		ip6->ip6_dst = sin6_dst->sin6_addr;
191	else  {
192		m_freem(m);
193		return ENETUNREACH;
194	}
195	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
196		       &otos, &itos);
197	ip6->ip6_flow &= ~htonl(0xff << 20);
198	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
199
200	if (dst->sin6_family != sin6_dst->sin6_family ||
201	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr) ||
202	    (sc->gif_ro6.ro_rt != NULL &&
203	    (sc->gif_ro6.ro_rt->generation_id != route_generation ||
204	    sc->gif_ro6.ro_rt->rt_ifp == ifp))) {
205		/* cache route doesn't match or recursive route */
206		bzero(dst, sizeof(*dst));
207		dst->sin6_family = sin6_dst->sin6_family;
208		dst->sin6_len = sizeof(struct sockaddr_in6);
209		dst->sin6_addr = sin6_dst->sin6_addr;
210		if (sc->gif_ro6.ro_rt) {
211			rtfree(sc->gif_ro6.ro_rt);
212			sc->gif_ro6.ro_rt = NULL;
213		}
214#if 0
215		sc->gif_if.if_mtu = GIF_MTU;
216#endif
217	}
218
219	if (sc->gif_ro6.ro_rt == NULL) {
220		rtalloc((struct route *)&sc->gif_ro6);
221		if (sc->gif_ro6.ro_rt == NULL) {
222			m_freem(m);
223			return ENETUNREACH;
224		}
225		RT_LOCK(sc->gif_ro6.ro_rt);
226		/* if it constitutes infinite encapsulation, punt. */
227		if (sc->gif_ro6.ro_rt->rt_ifp == ifp) {
228			RT_UNLOCK(sc->gif_ro6.ro_rt);
229			m_freem(m);
230			return ENETUNREACH;	/*XXX*/
231		}
232#if 0
233		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
234			- sizeof(struct ip6_hdr);
235#endif
236		RT_UNLOCK(sc->gif_ro6.ro_rt);
237	}
238
239#if IPV6_MINMTU
240	/*
241	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
242	 * it is too painful to ask for resend of inner packet, to achieve
243	 * path MTU discovery for encapsulated packets.
244	 */
245	return(ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL));
246#else
247	return(ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL));
248#endif
249}
250
251int in6_gif_input(struct mbuf **mp, int *offp, int proto)
252{
253	struct mbuf *m = *mp;
254	struct ifnet *gifp = NULL;
255	struct ip6_hdr *ip6;
256	int af = 0;
257	u_int32_t otos;
258
259	ip6 = mtod(m, struct ip6_hdr *);
260
261	gifp = ((struct gif_softc*)encap_getarg(m))->gif_if;
262
263	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
264		m_freem(m);
265		ip6stat.ip6s_nogif++;
266		return IPPROTO_DONE;
267	}
268
269	otos = ip6->ip6_flow;
270	m_adj(m, *offp);
271
272	switch (proto) {
273#if INET
274	case IPPROTO_IPV4:
275	    {
276		struct ip *ip;
277		u_int8_t otos8;
278		af = AF_INET;
279		otos8 = (ntohl(otos) >> 20) & 0xff;
280		if (mbuf_len(m) < sizeof(*ip)) {
281			m = m_pullup(m, sizeof(*ip));
282			if (!m)
283				return IPPROTO_DONE;
284		}
285		ip = mtod(m, struct ip *);
286		if (gifp->if_flags & IFF_LINK1)
287			ip_ecn_egress(ECN_ALLOWED, &otos8, &ip->ip_tos);
288		else
289			ip_ecn_egress(ECN_NOCARE, &otos8, &ip->ip_tos);
290		break;
291	    }
292#endif /* INET */
293#if INET6
294	case IPPROTO_IPV6:
295	    {
296		af = AF_INET6;
297		if (mbuf_len(m) < sizeof(*ip6)) {
298			m = m_pullup(m, sizeof(*ip6));
299			if (!m)
300				return IPPROTO_DONE;
301		}
302		ip6 = mtod(m, struct ip6_hdr *);
303		if (gifp->if_flags & IFF_LINK1)
304			ip6_ecn_egress(ECN_ALLOWED, &otos, &ip6->ip6_flow);
305		else
306			ip6_ecn_egress(ECN_NOCARE, &otos, &ip6->ip6_flow);
307		break;
308	    }
309#endif
310	default:
311		ip6stat.ip6s_nogif++;
312		m_freem(m);
313		return IPPROTO_DONE;
314	}
315
316	if (m->m_pkthdr.rcvif)  /* replace the rcvif by gifp for ifnet_input to route it correctly */
317		m->m_pkthdr.rcvif = gifp;
318
319	ifnet_input(gifp, m, NULL);
320	return IPPROTO_DONE;
321}
322
323/*
324 * validate outer address.
325 */
326static int
327gif_validate6(
328	const struct ip6_hdr *ip6,
329	struct gif_softc *sc,
330	struct ifnet *ifp)
331{
332	struct sockaddr_in6 *src, *dst;
333
334	src = (struct sockaddr_in6 *)(void *)sc->gif_psrc;
335	dst = (struct sockaddr_in6 *)(void *)sc->gif_pdst;
336
337	/*
338	 * Check for address match.  Note that the check is for an incoming
339	 * packet.  We should compare the *source* address in our configuration
340	 * and the *destination* address of the packet, and vice versa.
341	 */
342	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
343	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
344		return 0;
345
346	/* martian filters on outer source - done in ip6_input */
347
348	/* ingress filters on outer source */
349	if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 && ifp) {
350		struct sockaddr_in6 sin6;
351		struct rtentry *rt;
352
353		bzero(&sin6, sizeof(sin6));
354		sin6.sin6_family = AF_INET6;
355		sin6.sin6_len = sizeof(struct sockaddr_in6);
356		sin6.sin6_addr = ip6->ip6_src;
357
358		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0);
359		if (rt != NULL)
360			RT_LOCK(rt);
361		if (!rt || rt->rt_ifp != ifp) {
362#if 0
363			log(LOG_WARNING, "%s: packet from %s dropped "
364			    "due to ingress filter\n", if_name(&sc->gif_if),
365			    ip6_sprintf(&sin6.sin6_addr));
366#endif
367			if (rt != NULL) {
368				RT_UNLOCK(rt);
369				rtfree(rt);
370			}
371			return 0;
372		}
373		RT_UNLOCK(rt);
374		rtfree(rt);
375	}
376
377	return 128 * 2;
378}
379
380/*
381 * we know that we are in IFF_UP, outer address available, and outer family
382 * matched the physical addr family.  see gif_encapcheck().
383 * sanity check for arg should have been done in the caller.
384 */
385int
386gif_encapcheck6(
387	const struct mbuf *m,
388	__unused int off,
389	__unused int proto,
390	void *arg)
391{
392	struct ip6_hdr ip6;
393	struct gif_softc *sc;
394	struct ifnet *ifp;
395
396	/* sanity check done in caller */
397	sc = (struct gif_softc *)arg;
398
399	mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof(ip6), &ip6);
400	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
401
402	return gif_validate6(&ip6, sc, ifp);
403}
404