in_gif.c revision 78064 
1/*	$FreeBSD: head/sys/netinet/in_gif.c 78064 2001-06-11 12:39:29Z ume $	*/
2/*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 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
84int
85in_gif_output(ifp, family, m, rt)
86	struct ifnet	*ifp;
87	int		family;
88	struct mbuf	*m;
89	struct rtentry *rt;
90{
91	struct gif_softc *sc = (struct gif_softc*)ifp;
92	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
93	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
94	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
95	struct ip iphdr;	/* capsule IP header, host byte ordered */
96	int proto, error;
97	u_int8_t tos;
98
99	if (sin_src == NULL || sin_dst == NULL ||
100	    sin_src->sin_family != AF_INET ||
101	    sin_dst->sin_family != AF_INET) {
102		m_freem(m);
103		return EAFNOSUPPORT;
104	}
105
106	switch (family) {
107#ifdef INET
108	case AF_INET:
109	    {
110		struct ip *ip;
111
112		proto = IPPROTO_IPV4;
113		if (m->m_len < sizeof(*ip)) {
114			m = m_pullup(m, sizeof(*ip));
115			if (!m)
116				return ENOBUFS;
117		}
118		ip = mtod(m, struct ip *);
119		tos = ip->ip_tos;
120		break;
121	    }
122#endif /*INET*/
123#ifdef INET6
124	case AF_INET6:
125	    {
126		struct ip6_hdr *ip6;
127		proto = IPPROTO_IPV6;
128		if (m->m_len < sizeof(*ip6)) {
129			m = m_pullup(m, sizeof(*ip6));
130			if (!m)
131				return ENOBUFS;
132		}
133		ip6 = mtod(m, struct ip6_hdr *);
134		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
135		break;
136	    }
137#endif /*INET6*/
138	default:
139#ifdef DEBUG
140		printf("in_gif_output: warning: unknown family %d passed\n",
141			family);
142#endif
143		m_freem(m);
144		return EAFNOSUPPORT;
145	}
146
147	bzero(&iphdr, sizeof(iphdr));
148	iphdr.ip_src = sin_src->sin_addr;
149	/* bidirectional configured tunnel mode */
150	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
151		iphdr.ip_dst = sin_dst->sin_addr;
152	else {
153		m_freem(m);
154		return ENETUNREACH;
155	}
156	iphdr.ip_p = proto;
157	/* version will be set in ip_output() */
158	iphdr.ip_ttl = ip_gif_ttl;
159	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
160	if (ifp->if_flags & IFF_LINK1)
161		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
162	else
163		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
164
165	/* prepend new IP header */
166	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
167	if (m && m->m_len < sizeof(struct ip))
168		m = m_pullup(m, sizeof(struct ip));
169	if (m == NULL) {
170		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
171		return ENOBUFS;
172	}
173	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
174
175	if (dst->sin_family != sin_dst->sin_family ||
176	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
177		/* cache route doesn't match */
178		dst->sin_family = sin_dst->sin_family;
179		dst->sin_len = sizeof(struct sockaddr_in);
180		dst->sin_addr = sin_dst->sin_addr;
181		if (sc->gif_ro.ro_rt) {
182			RTFREE(sc->gif_ro.ro_rt);
183			sc->gif_ro.ro_rt = NULL;
184		}
185#if 0
186		sc->gif_if.if_mtu = GIF_MTU;
187#endif
188	}
189
190	if (sc->gif_ro.ro_rt == NULL) {
191		rtalloc(&sc->gif_ro);
192		if (sc->gif_ro.ro_rt == NULL) {
193			m_freem(m);
194			return ENETUNREACH;
195		}
196
197		/* if it constitutes infinite encapsulation, punt. */
198		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
199			m_freem(m);
200			return ENETUNREACH;	/*XXX*/
201		}
202#if 0
203		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
204			- sizeof(struct ip);
205#endif
206	}
207
208	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
209	return(error);
210}
211
212void
213#if __STDC__
214in_gif_input(struct mbuf *m, ...)
215#else
216in_gif_input(m, va_alist)
217	struct mbuf *m;
218	va_dcl
219#endif
220{
221	int off, proto;
222	struct ifnet *gifp = NULL;
223	struct ip *ip;
224	va_list ap;
225	int af;
226	u_int8_t otos;
227
228	va_start(ap, m);
229	off = va_arg(ap, int);
230	proto = va_arg(ap, int);
231	va_end(ap);
232
233	ip = mtod(m, struct ip *);
234
235	gifp = (struct ifnet *)encap_getarg(m);
236
237	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
238		m_freem(m);
239		ipstat.ips_nogif++;
240		return;
241	}
242
243	otos = ip->ip_tos;
244	m_adj(m, off);
245
246	switch (proto) {
247#ifdef INET
248	case IPPROTO_IPV4:
249	    {
250		struct ip *ip;
251		af = AF_INET;
252		if (m->m_len < sizeof(*ip)) {
253			m = m_pullup(m, sizeof(*ip));
254			if (!m)
255				return;
256		}
257		ip = mtod(m, struct ip *);
258		if (gifp->if_flags & IFF_LINK1)
259			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
260		else
261			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
262		break;
263	    }
264#endif
265#ifdef INET6
266	case IPPROTO_IPV6:
267	    {
268		struct ip6_hdr *ip6;
269		u_int8_t itos;
270		af = AF_INET6;
271		if (m->m_len < sizeof(*ip6)) {
272			m = m_pullup(m, sizeof(*ip6));
273			if (!m)
274				return;
275		}
276		ip6 = mtod(m, struct ip6_hdr *);
277		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
278		if (gifp->if_flags & IFF_LINK1)
279			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
280		else
281			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
282		ip6->ip6_flow &= ~htonl(0xff << 20);
283		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
284		break;
285	    }
286#endif /* INET6 */
287	default:
288		ipstat.ips_nogif++;
289		m_freem(m);
290		return;
291	}
292	gif_input(m, af, gifp);
293	return;
294}
295
296/*
297 * we know that we are in IFF_UP, outer address available, and outer family
298 * matched the physical addr family.  see gif_encapcheck().
299 */
300int
301gif_encapcheck4(m, off, proto, arg)
302	const struct mbuf *m;
303	int off;
304	int proto;
305	void *arg;
306{
307	struct ip ip;
308	struct gif_softc *sc;
309	struct sockaddr_in *src, *dst;
310	int addrmatch;
311	struct in_ifaddr *ia4;
312
313	/* sanity check done in caller */
314	sc = (struct gif_softc *)arg;
315	src = (struct sockaddr_in *)sc->gif_psrc;
316	dst = (struct sockaddr_in *)sc->gif_pdst;
317
318	/* LINTED const cast */
319	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
320
321	/* check for address match */
322	addrmatch = 0;
323	if (src->sin_addr.s_addr == ip.ip_dst.s_addr)
324		addrmatch |= 1;
325	if (dst->sin_addr.s_addr == ip.ip_src.s_addr)
326		addrmatch |= 2;
327	if (addrmatch != 3)
328		return 0;
329
330	/* martian filters on outer source - NOT done in ip_input! */
331	if (IN_MULTICAST(ntohl(ip.ip_src.s_addr)))
332		return 0;
333	switch ((ntohl(ip.ip_src.s_addr) & 0xff000000) >> 24) {
334	case 0: case 127: case 255:
335		return 0;
336	}
337	/* reject packets with broadcast on source */
338	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link)
339	{
340		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
341			continue;
342		if (ip.ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
343			return 0;
344	}
345
346	/* ingress filters on outer source */
347	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 &&
348	    (m->m_flags & M_PKTHDR) != 0 && m->m_pkthdr.rcvif) {
349		struct sockaddr_in sin;
350		struct rtentry *rt;
351
352		bzero(&sin, sizeof(sin));
353		sin.sin_family = AF_INET;
354		sin.sin_len = sizeof(struct sockaddr_in);
355		sin.sin_addr = ip.ip_src;
356		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
357		if (!rt || rt->rt_ifp != m->m_pkthdr.rcvif) {
358#if 0
359			log(LOG_WARNING, "%s: packet from 0x%x dropped "
360			    "due to ingress filter\n", if_name(&sc->gif_if),
361			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
362#endif
363			if (rt)
364				rtfree(rt);
365			return 0;
366		}
367		rtfree(rt);
368	}
369
370	return 32 * 2;
371}
372