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#if MROUTING
89#include <netinet/ip_mroute.h>
90#endif /* MROUTING */
91
92#include <net/if_gif.h>
93
94#include <net/net_osdep.h>
95
96int ip_gif_ttl = GIF_TTL;
97SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW | CTLFLAG_LOCKED,
98	&ip_gif_ttl,	0, "");
99
100int
101in_gif_output(
102	struct ifnet	*ifp,
103	int		family,
104	struct mbuf	*m,
105	__unused struct rtentry *rt)
106{
107	struct gif_softc *sc = ifnet_softc(ifp);
108	struct sockaddr_in *dst = (struct sockaddr_in *)
109	    (void *)&sc->gif_ro.ro_dst;
110	struct sockaddr_in *sin_src = (struct sockaddr_in *)
111	    (void *)sc->gif_psrc;
112	struct sockaddr_in *sin_dst = (struct sockaddr_in *)
113	    (void *)sc->gif_pdst;
114	struct ip iphdr;	/* capsule IP header, host byte ordered */
115	int proto, error;
116	u_int8_t tos;
117	struct ip_out_args ipoa =
118	    { IFSCOPE_NONE, { 0 }, IPOAF_SELECT_SRCIF, 0 };
119
120	GIF_LOCK_ASSERT(sc);
121
122	if (sin_src == NULL || sin_dst == NULL ||
123	    sin_src->sin_family != AF_INET ||
124	    sin_dst->sin_family != AF_INET) {
125		m_freem(m);
126		return (EAFNOSUPPORT);
127	}
128
129	switch (family) {
130#if INET
131	case AF_INET:
132	    {
133		struct ip *ip;
134
135		proto = IPPROTO_IPV4;
136		if (mbuf_len(m) < sizeof (*ip)) {
137			m = m_pullup(m, sizeof (*ip));
138			if (!m)
139				return (ENOBUFS);
140		}
141		ip = mtod(m, struct ip *);
142		tos = ip->ip_tos;
143		break;
144	    }
145#endif /* INET */
146#if INET6
147	case AF_INET6:
148	    {
149		struct ip6_hdr *ip6;
150		proto = IPPROTO_IPV6;
151		if (mbuf_len(m) < sizeof (*ip6)) {
152			m = m_pullup(m, sizeof (*ip6));
153			if (!m)
154				return (ENOBUFS);
155		}
156		ip6 = mtod(m, struct ip6_hdr *);
157		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
158		break;
159	    }
160#endif /* INET6 */
161	default:
162#if DEBUG
163		printf("in_gif_output: warning: unknown family %d passed\n",
164			family);
165#endif
166		m_freem(m);
167		return (EAFNOSUPPORT);
168	}
169
170	bzero(&iphdr, sizeof (iphdr));
171	iphdr.ip_src = sin_src->sin_addr;
172	/* bidirectional configured tunnel mode */
173	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
174		iphdr.ip_dst = sin_dst->sin_addr;
175	else {
176		m_freem(m);
177		return (ENETUNREACH);
178	}
179	iphdr.ip_p = proto;
180	/* version will be set in ip_output() */
181	iphdr.ip_ttl = ip_gif_ttl;
182	iphdr.ip_len = m->m_pkthdr.len + sizeof (struct ip);
183	if (ifp->if_flags & IFF_LINK1)
184		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
185	else
186		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
187
188	/* prepend new IP header */
189	M_PREPEND(m, sizeof (struct ip), M_DONTWAIT);
190	if (m && mbuf_len(m) < sizeof (struct ip))
191		m = m_pullup(m, sizeof (struct ip));
192	if (m == NULL) {
193		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
194		return (ENOBUFS);
195	}
196	bcopy(&iphdr, mtod(m, struct ip *), sizeof (struct ip));
197
198	if (ROUTE_UNUSABLE(&sc->gif_ro) ||
199	    dst->sin_family != sin_dst->sin_family ||
200	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr ||
201	    (sc->gif_ro.ro_rt != NULL && sc->gif_ro.ro_rt->rt_ifp == ifp)) {
202		/* cache route doesn't match or recursive route */
203		dst->sin_family = sin_dst->sin_family;
204		dst->sin_len = sizeof (struct sockaddr_in);
205		dst->sin_addr = sin_dst->sin_addr;
206		ROUTE_RELEASE(&sc->gif_ro);
207#if 0
208		sc->gif_if.if_mtu = GIF_MTU;
209#endif
210	}
211
212	if (sc->gif_ro.ro_rt == NULL) {
213		rtalloc(&sc->gif_ro);
214		if (sc->gif_ro.ro_rt == NULL) {
215			m_freem(m);
216			return (ENETUNREACH);
217		}
218
219		/* if it constitutes infinite encapsulation, punt. */
220		RT_LOCK(sc->gif_ro.ro_rt);
221		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
222			RT_UNLOCK(sc->gif_ro.ro_rt);
223			m_freem(m);
224			return (ENETUNREACH); /* XXX */
225		}
226#if 0
227		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
228		    - sizeof (struct ip);
229#endif
230		RT_UNLOCK(sc->gif_ro.ro_rt);
231	}
232
233	error = ip_output(m, NULL, &sc->gif_ro, IP_OUTARGS, NULL, &ipoa);
234
235	return (error);
236}
237
238void
239in_gif_input(m, off)
240	struct mbuf *m;
241	int off;
242{
243	struct ifnet *gifp = NULL;
244	struct ip *ip;
245	int af, proto;
246	u_int8_t otos;
247
248	ip = mtod(m, struct ip *);
249	proto = ip->ip_p;
250
251
252	gifp = ((struct gif_softc *)encap_getarg(m))->gif_if;
253
254	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
255		m_freem(m);
256		OSAddAtomic(1, &ipstat.ips_nogif);
257		return;
258	}
259
260	otos = ip->ip_tos;
261	m_adj(m, off);
262
263	switch (proto) {
264#if INET
265	case IPPROTO_IPV4:
266	    {
267		af = AF_INET;
268		if (mbuf_len(m) < sizeof (*ip)) {
269			m = m_pullup(m, sizeof (*ip));
270			if (!m)
271				return;
272		}
273		ip = mtod(m, struct ip *);
274		if (gifp->if_flags & IFF_LINK1)
275			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
276		else
277			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
278		break;
279	    }
280#endif
281#if INET6
282	case IPPROTO_IPV6:
283	    {
284		struct ip6_hdr *ip6;
285		u_int8_t itos;
286		af = AF_INET6;
287		if (mbuf_len(m) < sizeof (*ip6)) {
288			m = m_pullup(m, sizeof (*ip6));
289			if (!m)
290				return;
291		}
292		ip6 = mtod(m, struct ip6_hdr *);
293		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
294		if (gifp->if_flags & IFF_LINK1)
295			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
296		else
297			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
298		ip6->ip6_flow &= ~htonl(0xff << 20);
299		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
300		break;
301	    }
302#endif /* INET6 */
303	default:
304		OSAddAtomic(1, &ipstat.ips_nogif);
305		m_freem(m);
306		return;
307	}
308#ifdef __APPLE__
309	/* Replace the rcvif by gifp for dlil to route it correctly */
310	if (m->m_pkthdr.rcvif)
311		m->m_pkthdr.rcvif = gifp;
312	ifnet_input(gifp, m, NULL);
313#else
314	gif_input(m, af, gifp);
315#endif
316}
317
318/*
319 * We know that we are in IFF_UP, outer address available, and outer family
320 * matched the physical addr family.  see gif_encapcheck().
321 */
322int
323gif_encapcheck4(
324	const struct mbuf *m,
325	__unused int off,
326	__unused int proto,
327	void *arg)
328{
329	struct ip ip;
330	struct gif_softc *sc;
331	struct sockaddr_in *src, *dst;
332	int addrmatch;
333	struct in_ifaddr *ia4;
334
335	/* sanity check done in caller */
336	sc = (struct gif_softc *)arg;
337	src = (struct sockaddr_in *)(void *)sc->gif_psrc;
338	dst = (struct sockaddr_in *)(void *)sc->gif_pdst;
339
340	GIF_LOCK_ASSERT(sc);
341
342	mbuf_copydata((struct mbuf *)(size_t)m, 0, sizeof (ip), &ip);
343
344	/* check for address match */
345	addrmatch = 0;
346	if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
347		addrmatch |= 1;
348	if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
349		addrmatch |= 2;
350	if (addrmatch != 3)
351		return (0);
352
353	/* martian filters on outer source - NOT done in ip_input! */
354	if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
355		return (0);
356	switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
357	case 0: case 127: case 255:
358		return (0);
359	}
360	/* reject packets with broadcast on source */
361	lck_rw_lock_shared(in_ifaddr_rwlock);
362	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
363	    ia4 = TAILQ_NEXT(ia4, ia_link)) {
364		if ((ifnet_flags(ia4->ia_ifa.ifa_ifp) & IFF_BROADCAST) == 0)
365			continue;
366		IFA_LOCK(&ia4->ia_ifa);
367		if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
368			IFA_UNLOCK(&ia4->ia_ifa);
369			lck_rw_done(in_ifaddr_rwlock);
370			return (0);
371		}
372		IFA_UNLOCK(&ia4->ia_ifa);
373	}
374	lck_rw_done(in_ifaddr_rwlock);
375
376	/* ingress filters on outer source */
377	if ((ifnet_flags(sc->gif_if) & IFF_LINK2) == 0 &&
378	    (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
379		struct sockaddr_in sin;
380		struct rtentry *rt;
381
382		bzero(&sin, sizeof (sin));
383		sin.sin_family = AF_INET;
384		sin.sin_len = sizeof (struct sockaddr_in);
385		sin.sin_addr = ip.ip_src;
386		rt = rtalloc1_scoped((struct sockaddr *)&sin, 0, 0,
387		    m->m_pkthdr.rcvif->if_index);
388		if (rt != NULL)
389			RT_LOCK(rt);
390		if (rt == NULL || rt->rt_ifp != m->m_pkthdr.rcvif) {
391			if (rt != NULL) {
392				RT_UNLOCK(rt);
393				rtfree(rt);
394			}
395			return (0);
396		}
397		RT_UNLOCK(rt);
398		rtfree(rt);
399	}
400
401	return (32 * 2);
402}
403