1/*
2 * Copyright (c) 2000-2013 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/* $KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $ */
29
30/*
31 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
32 * All rights reserved.
33 *
34 * Redistribution and use in source and binary forms, with or without
35 * modification, are permitted provided that the following conditions
36 * are met:
37 * 1. Redistributions of source code must retain the above copyright
38 *    notice, this list of conditions and the following disclaimer.
39 * 2. Redistributions in binary form must reproduce the above copyright
40 *    notice, this list of conditions and the following disclaimer in the
41 *    documentation and/or other materials provided with the distribution.
42 * 3. Neither the name of the project nor the names of its contributors
43 *    may be used to endorse or promote products derived from this software
44 *    without specific prior written permission.
45 *
46 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
47 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
48 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
49 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
50 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
51 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
52 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
53 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
54 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
55 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
56 * SUCH DAMAGE.
57 */
58
59
60#include <sys/param.h>
61#include <sys/systm.h>
62#include <sys/socket.h>
63#include <sys/sockio.h>
64#include <sys/mbuf.h>
65#include <sys/errno.h>
66#include <sys/kernel.h>
67#include <sys/sysctl.h>
68
69#include <sys/malloc.h>
70#include <libkern/OSAtomic.h>
71
72#include <net/if.h>
73#include <net/route.h>
74
75#include <netinet/in.h>
76#include <netinet/in_systm.h>
77#include <netinet/ip.h>
78#include <netinet/ip_var.h>
79#include <netinet/in_gif.h>
80#include <netinet/in_var.h>
81#include <netinet/ip_encap.h>
82#include <netinet/ip_ecn.h>
83
84#if INET6
85#include <netinet/ip6.h>
86#endif
87
88#include <net/if_gif.h>
89
90#include <net/net_osdep.h>
91
92int ip_gif_ttl = GIF_TTL;
93SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW | CTLFLAG_LOCKED,
94	&ip_gif_ttl,	0, "");
95
96int
97in_gif_output(
98	struct ifnet	*ifp,
99	int		family,
100	struct mbuf	*m,
101	__unused struct rtentry *rt)
102{
103	struct gif_softc *sc = ifnet_softc(ifp);
104	struct sockaddr_in *dst = (struct sockaddr_in *)
105	    (void *)&sc->gif_ro.ro_dst;
106	struct sockaddr_in *sin_src = (struct sockaddr_in *)
107	    (void *)sc->gif_psrc;
108	struct sockaddr_in *sin_dst = (struct sockaddr_in *)
109	    (void *)sc->gif_pdst;
110	struct ip iphdr;	/* capsule IP header, host byte ordered */
111	int proto, error;
112	u_int8_t tos;
113	struct ip_out_args ipoa =
114	    { IFSCOPE_NONE, { 0 }, IPOAF_SELECT_SRCIF, 0 };
115
116	GIF_LOCK_ASSERT(sc);
117
118	if (sin_src == NULL || sin_dst == NULL ||
119	    sin_src->sin_family != AF_INET ||
120	    sin_dst->sin_family != AF_INET) {
121		m_freem(m);
122		return (EAFNOSUPPORT);
123	}
124
125	switch (family) {
126#if INET
127	case AF_INET:
128	    {
129		struct ip *ip;
130
131		proto = IPPROTO_IPV4;
132		if (mbuf_len(m) < sizeof (*ip)) {
133			m = m_pullup(m, sizeof (*ip));
134			if (!m)
135				return (ENOBUFS);
136		}
137		ip = mtod(m, struct ip *);
138		tos = ip->ip_tos;
139		break;
140	    }
141#endif /* INET */
142#if INET6
143	case AF_INET6:
144	    {
145		struct ip6_hdr *ip6;
146		proto = IPPROTO_IPV6;
147		if (mbuf_len(m) < sizeof (*ip6)) {
148			m = m_pullup(m, sizeof (*ip6));
149			if (!m)
150				return (ENOBUFS);
151		}
152		ip6 = mtod(m, struct ip6_hdr *);
153		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
154		break;
155	    }
156#endif /* INET6 */
157	default:
158#if DEBUG
159		printf("in_gif_output: warning: unknown family %d passed\n",
160			family);
161#endif
162		m_freem(m);
163		return (EAFNOSUPPORT);
164	}
165
166	bzero(&iphdr, sizeof (iphdr));
167	iphdr.ip_src = sin_src->sin_addr;
168	/* bidirectional configured tunnel mode */
169	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
170		iphdr.ip_dst = sin_dst->sin_addr;
171	else {
172		m_freem(m);
173		return (ENETUNREACH);
174	}
175	iphdr.ip_p = proto;
176	/* version will be set in ip_output() */
177	iphdr.ip_ttl = ip_gif_ttl;
178	iphdr.ip_len = m->m_pkthdr.len + sizeof (struct ip);
179	if (ifp->if_flags & IFF_LINK1)
180		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
181	else
182		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
183
184	/* prepend new IP header */
185	M_PREPEND(m, sizeof (struct ip), M_DONTWAIT);
186	if (m && mbuf_len(m) < sizeof (struct ip))
187		m = m_pullup(m, sizeof (struct ip));
188	if (m == NULL) {
189		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
190		return (ENOBUFS);
191	}
192	bcopy(&iphdr, mtod(m, struct ip *), sizeof (struct ip));
193
194	if (ROUTE_UNUSABLE(&sc->gif_ro) ||
195	    dst->sin_family != sin_dst->sin_family ||
196	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
197	    (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
198		/* cache route doesn't match or recursive route */
199		dst->sin_family = sin_dst->sin_family;
200		dst->sin_len = sizeof (struct sockaddr_in);
201		dst->sin_addr = sin_dst->sin_addr;
202		ROUTE_RELEASE(&sc->gif_ro);
203#if 0
204		sc->gif_if.if_mtu = GIF_MTU;
205#endif
206	}
207
208	if (sc->gif_ro.ro_rt == NULL) {
209		rtalloc(&sc->gif_ro);
210		if (sc->gif_ro.ro_rt == NULL) {
211			m_freem(m);
212			return (ENETUNREACH);
213		}
214
215		/* if it constitutes infinite encapsulation, punt. */
216		RT_LOCK(sc->gif_ro.ro_rt);
217		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
218			RT_UNLOCK(sc->gif_ro.ro_rt);
219			m_freem(m);
220			return (ENETUNREACH); /* XXX */
221		}
222#if 0
223		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
224		    - sizeof (struct ip);
225#endif
226		RT_UNLOCK(sc->gif_ro.ro_rt);
227	}
228
229	error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
230
231	return (error);
232}
233
234void
235in_gif_input(m, off)
236	struct mbuf *m;
237	int off;
238{
239	struct ifnet *gifp = NULL;
240	struct ip *ip;
241	int af, proto;
242	u_int8_t otos;
243
244	ip = mtod(m, struct ip *);
245	proto = ip->ip_p;
246
247
248	gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
249
250	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
251		m_freem(m);
252		OSAddAtomic(1, &ipstat.ips_nogif);
253		return;
254	}
255
256	otos = ip->ip_tos;
257	m_adj(m, off);
258
259	switch (proto) {
260#if INET
261	case IPPROTO_IPV4:
262	    {
263		af = AF_INET;
264		if (mbuf_len(m) < sizeof (*ip)) {
265			m = m_pullup(m, sizeof (*ip));
266			if (!m)
267				return;
268		}
269		ip = mtod(m, struct ip *);
270		if (gifp->if_flags & IFF_LINK1)
271			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
272		else
273			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
274		break;
275	    }
276#endif
277#if INET6
278	case IPPROTO_IPV6:
279	    {
280		struct ip6_hdr *ip6;
281		u_int8_t itos;
282		af = AF_INET6;
283		if (mbuf_len(m) < sizeof (*ip6)) {
284			m = m_pullup(m, sizeof (*ip6));
285			if (!m)
286				return;
287		}
288		ip6 = mtod(m, struct ip6_hdr *);
289		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
290		if (gifp->if_flags & IFF_LINK1)
291			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
292		else
293			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
294		ip6->ip6_flow &= ~htonl(0xff << 20);
295		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
296		break;
297	    }
298#endif /* INET6 */
299	default:
300		OSAddAtomic(1, &ipstat.ips_nogif);
301		m_freem(m);
302		return;
303	}
304#ifdef __APPLE__
305	/* Replace the rcvif by gifp for dlil to route it correctly */
306	if (m->m_pkthdr.rcvif)
307		m->m_pkthdr.rcvif = gifp;
308	ifnet_input(gifp, m, NULL);
309#else
310	gif_input(m, af, gifp);
311#endif
312}
313
314/*
315 * We know that we are in IFF_UP, outer address available, and outer family
316 * matched the physical addr family.  see gif_encapcheck().
317 */
318int
319gif_encapcheck4(
320	const struct mbuf *m,
321	__unused int off,
322	__unused int proto,
323	void *arg)
324{
325	struct ip ip;
326	struct gif_softc *sc;
327	struct sockaddr_in *src, *dst;
328	int addrmatch;
329	struct in_ifaddr *ia4;
330
331	/* sanity check done in caller */
332	sc = (struct gif_softc *)arg;
333	src = (struct sockaddr_in *)(void *)sc->gif_psrc;
334	dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
335
336	GIF_LOCK_ASSERT(sc);
337
338	mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof (ip), &ip);
339
340	/* check for address match */
341	addrmatch = 0;
342	if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
343		addrmatch |= 1;
344	if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
345		addrmatch |= 2;
346	if (addrmatch != 3)
347		return (0);
348
349	/* martian filters on outer source - NOT done in ip_input! */
350	if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
351		return (0);
352	switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
353	case 0: case 127: case 255:
354		return (0);
355	}
356	/* reject packets with broadcast on source */
357	lck_rw_lock_shared(in_ifaddr_rwlock);
358	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
359	    ia4 = TAILQ_NEXT(ia4, ia_link)) {
360		if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
361			continue;
362		IFA_LOCK(&ia4->ia_ifa);
363		if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
364			IFA_UNLOCK(&ia4->ia_ifa);
365			lck_rw_done(in_ifaddr_rwlock);
366			return (0);
367		}
368		IFA_UNLOCK(&ia4->ia_ifa);
369	}
370	lck_rw_done(in_ifaddr_rwlock);
371
372	/* ingress filters on outer source */
373	if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
374	    (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
375		struct sockaddr_in sin;
376		struct rtentry *rt;
377
378		bzero(&sin, sizeof (sin));
379		sin.sin_family = AF_INET;
380		sin.sin_len = sizeof (struct sockaddr_in);
381		sin.sin_addr = ip.ip_src;
382		rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
383		    m->m_pkthdr.rcvif->if_index);
384		if (rt != NULL)
385			RT_LOCK(rt);
386		if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
387			if (rt != NULL) {
388				RT_UNLOCK(rt);
389				rtfree(rt);
390			}
391			return (0);
392		}
393		RT_UNLOCK(rt);
394		rtfree(rt);
395	}
396
397	return (32 * 2);
398}
399