in_gif.c revision 62587 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 62587 2000-07-04 16:35:15Z itojun $	*/
2/*	$KAME: in_gif.c,v 1.43 2000/06/20 19:45:00 itojun Exp $	*/
3
4/*
5 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the project nor the names of its contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include "opt_mrouting.h"
34#include "opt_inet.h"
35#include "opt_inet6.h"
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/socket.h>
40#include <sys/sockio.h>
41#include <sys/mbuf.h>
42#include <sys/errno.h>
43#include <sys/kernel.h>
44#include <sys/sysctl.h>
45
46#include <sys/malloc.h>
47
48#include <net/if.h>
49#include <net/route.h>
50
51#include <netinet/in.h>
52#include <netinet/in_systm.h>
53#include <netinet/ip.h>
54#include <netinet/ip_var.h>
55#include <netinet/in_gif.h>
56#include <netinet/in_var.h>
57#include <netinet/ip_encap.h>
58#include <netinet/ip_ecn.h>
59
60#ifdef INET6
61#include <netinet/ip6.h>
62#endif
63
64#ifdef MROUTING
65#include <netinet/ip_mroute.h>
66#endif /* MROUTING */
67
68#include <net/if_gif.h>
69
70#include "gif.h"
71
72#include <machine/stdarg.h>
73
74#include <net/net_osdep.h>
75
76#if NGIF > 0
77int ip_gif_ttl = GIF_TTL;
78#else
79int ip_gif_ttl = 0;
80#endif
81SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
82	&ip_gif_ttl,	0, "");
83
84#ifndef offsetof
85#define offsetof(s, e) ((int)&((s *)0)->e)
86#endif
87
88int
89in_gif_output(ifp, family, m, rt)
90	struct ifnet	*ifp;
91	int		family;
92	struct mbuf	*m;
93	struct rtentry *rt;
94{
95	register struct gif_softc *sc = (struct gif_softc*)ifp;
96	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
97	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
98	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
99	struct ip iphdr;	/* capsule IP header, host byte ordered */
100	int proto, error;
101	u_int8_t tos;
102
103	if (sin_src == NULL || sin_dst == NULL ||
104	    sin_src->sin_family != AF_INET ||
105	    sin_dst->sin_family != AF_INET) {
106		m_freem(m);
107		return EAFNOSUPPORT;
108	}
109
110	switch (family) {
111#ifdef INET
112	case AF_INET:
113	    {
114		struct ip *ip;
115
116		proto = IPPROTO_IPV4;
117		if (m->m_len < sizeof(*ip)) {
118			m = m_pullup(m, sizeof(*ip));
119			if (!m)
120				return ENOBUFS;
121		}
122		ip = mtod(m, struct ip *);
123		tos = ip->ip_tos;
124		break;
125	    }
126#endif /*INET*/
127#ifdef INET6
128	case AF_INET6:
129	    {
130		struct ip6_hdr *ip6;
131		proto = IPPROTO_IPV6;
132		if (m->m_len < sizeof(*ip6)) {
133			m = m_pullup(m, sizeof(*ip6));
134			if (!m)
135				return ENOBUFS;
136		}
137		ip6 = mtod(m, struct ip6_hdr *);
138		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139		break;
140	    }
141#endif /*INET6*/
142	default:
143#ifdef DEBUG
144		printf("in_gif_output: warning: unknown family %d passed\n",
145			family);
146#endif
147		m_freem(m);
148		return EAFNOSUPPORT;
149	}
150
151	bzero(&iphdr, sizeof(iphdr));
152	iphdr.ip_src = sin_src->sin_addr;
153	if (ifp->if_flags & IFF_LINK0) {
154		/* multi-destination mode */
155		if (sin_dst->sin_addr.s_addr != INADDR_ANY)
156			iphdr.ip_dst = sin_dst->sin_addr;
157		else if (rt) {
158			if (family != AF_INET) {
159				m_freem(m);
160				return EINVAL;	/*XXX*/
161			}
162			iphdr.ip_dst = ((struct sockaddr_in *)
163					(rt->rt_gateway))->sin_addr;
164		} else {
165			m_freem(m);
166			return ENETUNREACH;
167		}
168	} else {
169		/* bidirectional configured tunnel mode */
170		if (sin_dst->sin_addr.s_addr != INADDR_ANY)
171			iphdr.ip_dst = sin_dst->sin_addr;
172		else {
173			m_freem(m);
174			return ENETUNREACH;
175		}
176	}
177	iphdr.ip_p = proto;
178	/* version will be set in ip_output() */
179	iphdr.ip_ttl = ip_gif_ttl;
180	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
181	if (ifp->if_flags & IFF_LINK1)
182		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
183
184	/* prepend new IP header */
185	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
186	if (m && m->m_len < 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 (dst->sin_family != sin_dst->sin_family ||
195	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
196		/* cache route doesn't match */
197		dst->sin_family = sin_dst->sin_family;
198		dst->sin_len = sizeof(struct sockaddr_in);
199		dst->sin_addr = sin_dst->sin_addr;
200		if (sc->gif_ro.ro_rt) {
201			RTFREE(sc->gif_ro.ro_rt);
202			sc->gif_ro.ro_rt = NULL;
203		}
204#if 0
205		sc->gif_if.if_mtu = GIF_MTU;
206#endif
207	}
208
209	if (sc->gif_ro.ro_rt == NULL) {
210		rtalloc(&sc->gif_ro);
211		if (sc->gif_ro.ro_rt == NULL) {
212			m_freem(m);
213			return ENETUNREACH;
214		}
215
216		/* if it constitutes infinite encapsulation, punt. */
217		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
218			m_freem(m);
219			return ENETUNREACH;	/*XXX*/
220		}
221#if 0
222		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
223			- sizeof(struct ip);
224#endif
225	}
226
227	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
228	return(error);
229}
230
231void
232#if __STDC__
233in_gif_input(struct mbuf *m, ...)
234#else
235in_gif_input(m, va_alist)
236	struct mbuf *m;
237	va_dcl
238#endif
239{
240	int off, proto;
241	struct ifnet *gifp = NULL;
242	struct ip *ip;
243	va_list ap;
244	int af;
245	u_int8_t otos;
246
247	va_start(ap, m);
248	off = va_arg(ap, int);
249	proto = va_arg(ap, int);
250	va_end(ap);
251
252	ip = mtod(m, struct ip *);
253
254	gifp = (struct ifnet *)encap_getarg(m);
255
256	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
257		m_freem(m);
258		ipstat.ips_nogif++;
259		return;
260	}
261
262	otos = ip->ip_tos;
263	m_adj(m, off);
264
265	switch (proto) {
266#ifdef INET
267	case IPPROTO_IPV4:
268	    {
269		struct ip *ip;
270		af = AF_INET;
271		if (m->m_len < sizeof(*ip)) {
272			m = m_pullup(m, sizeof(*ip));
273			if (!m)
274				return;
275		}
276		ip = mtod(m, struct ip *);
277		if (gifp->if_flags & IFF_LINK1)
278			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
279		break;
280	    }
281#endif
282#ifdef INET6
283	case IPPROTO_IPV6:
284	    {
285		struct ip6_hdr *ip6;
286		u_int8_t itos;
287		af = AF_INET6;
288		if (m->m_len < sizeof(*ip6)) {
289			m = m_pullup(m, sizeof(*ip6));
290			if (!m)
291				return;
292		}
293		ip6 = mtod(m, struct ip6_hdr *);
294		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
295		if (gifp->if_flags & IFF_LINK1)
296			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
297		ip6->ip6_flow &= ~htonl(0xff << 20);
298		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
299		break;
300	    }
301#endif /* INET6 */
302	default:
303		ipstat.ips_nogif++;
304		m_freem(m);
305		return;
306	}
307	gif_input(m, af, gifp);
308	return;
309}
310
311/*
312 * we know that we are in IFF_UP, outer address available, and outer family
313 * matched the physical addr family.  see gif_encapcheck().
314 */
315int
316gif_encapcheck4(m, off, proto, arg)
317	const struct mbuf *m;
318	int off;
319	int proto;
320	void *arg;
321{
322	struct ip ip;
323	struct gif_softc *sc;
324	struct sockaddr_in *src, *dst;
325	int addrmatch;
326	struct in_ifaddr *ia4;
327
328	/* sanity check done in caller */
329	sc = (struct gif_softc *)arg;
330	src = (struct sockaddr_in *)sc->gif_psrc;
331	dst = (struct sockaddr_in *)sc->gif_pdst;
332
333	/* LINTED const cast */
334	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
335
336	/* check for address match */
337	addrmatch = 0;
338	if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
339		addrmatch |= 1;
340	if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
341		addrmatch |= 2;
342	else if ((sc->gif_if.if_flags & IFF_LINK0) != 0 &&
343		 dst->sin_addr.s_addr == INADDR_ANY) {
344		addrmatch |= 2; /* we accept any source */
345	}
346	if (addrmatch != 3)
347		return 0;
348
349	/* martian filters on outer source - NOT done in ip_input! */
350	if (IN_MULTICAST(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	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
358	     ia4 = TAILQ_NEXT(ia4, ia_link))
359	{
360		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
361			continue;
362		if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
363			return 0;
364	}
365
366	/* ingress filters on outer source */
367	if ((m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
368		struct sockaddr_in sin;
369		struct rtentry *rt;
370
371		bzero(&sin, sizeof(sin));
372		sin.sin_family = AF_INET;
373		sin.sin_len = sizeof(struct sockaddr_in);
374		sin.sin_addr = ip.ip_src;
375		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
376		if (!rt)
377			return 0;
378		if (rt->rt_ifp != m->m_pkthdr.rcvif) {
379			rtfree(rt);
380			return 0;
381		}
382		rtfree(rt);
383	}
384
385	/* prioritize: IFF_LINK0 mode is less preferred */
386	return (sc->gif_if.if_flags & IFF_LINK0) ? 32 : 32 * 2;
387}
388