xref: /freebsd/sys/netinet/in_gif.c (revision 63f9a4cb2684a303e3eb2ffed39c03a2e2b28ae0) 
1 /*	$FreeBSD$	*/
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 #include <sys/protosw.h>
46 
47 #include <sys/malloc.h>
48 
49 #include <net/if.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/ip.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/in_gif.h>
57 #include <netinet/in_var.h>
58 #include <netinet/ip_encap.h>
59 #include <netinet/ip_ecn.h>
60 
61 #ifdef INET6
62 #include <netinet/ip6.h>
63 #endif
64 
65 #ifdef MROUTING
66 #include <netinet/ip_mroute.h>
67 #endif /* MROUTING */
68 
69 #include <net/if_gif.h>
70 
71 #include <net/net_osdep.h>
72 
73 static int gif_validate4(const struct ip *, struct gif_softc *,
74 	struct ifnet *);
75 
76 extern  struct domain inetdomain;
77 struct protosw in_gif_protosw =
78 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
79   in_gif_input,	(pr_output_t*)rip_output, 0,	rip_ctloutput,
80   0,
81   0,		0,		0,		0,
82   &rip_usrreqs
83 };
84 
85 static int ip_gif_ttl = GIF_TTL;
86 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
87 	&ip_gif_ttl,	0, "");
88 
89 int
90 in_gif_output(ifp, family, m)
91 	struct ifnet	*ifp;
92 	int		family;
93 	struct mbuf	*m;
94 {
95 	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 	/* bidirectional configured tunnel mode */
154 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
155 		iphdr.ip_dst = sin_dst->sin_addr;
156 	else {
157 		m_freem(m);
158 		return ENETUNREACH;
159 	}
160 	iphdr.ip_p = proto;
161 	/* version will be set in ip_output() */
162 	iphdr.ip_ttl = ip_gif_ttl;
163 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
164 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
165 		       &iphdr.ip_tos, &tos);
166 
167 	/* prepend new IP header */
168 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
169 	if (m && m->m_len < sizeof(struct ip))
170 		m = m_pullup(m, sizeof(struct ip));
171 	if (m == NULL) {
172 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
173 		return ENOBUFS;
174 	}
175 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
176 
177 	if (dst->sin_family != sin_dst->sin_family ||
178 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
179 		/* cache route doesn't match */
180 		bzero(dst, sizeof(*dst));
181 		dst->sin_family = sin_dst->sin_family;
182 		dst->sin_len = sizeof(struct sockaddr_in);
183 		dst->sin_addr = sin_dst->sin_addr;
184 		if (sc->gif_ro.ro_rt) {
185 			RTFREE(sc->gif_ro.ro_rt);
186 			sc->gif_ro.ro_rt = NULL;
187 		}
188 #if 0
189 		sc->gif_if.if_mtu = GIF_MTU;
190 #endif
191 	}
192 
193 	if (sc->gif_ro.ro_rt == NULL) {
194 		rtalloc_ign(&sc->gif_ro, 0);
195 		if (sc->gif_ro.ro_rt == NULL) {
196 			m_freem(m);
197 			return ENETUNREACH;
198 		}
199 
200 		/* if it constitutes infinite encapsulation, punt. */
201 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
202 			m_freem(m);
203 			return ENETUNREACH;	/* XXX */
204 		}
205 #if 0
206 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
207 			- sizeof(struct ip);
208 #endif
209 	}
210 
211 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
212 
213 	if ((sc->gif_if.if_flags & IFF_LINK0) == 0) {
214 		RTFREE(sc->gif_ro.ro_rt);
215 		sc->gif_ro.ro_rt = NULL;
216 	}
217 
218 	return (error);
219 }
220 
221 void
222 in_gif_input(m, off)
223 	struct mbuf *m;
224 	int off;
225 {
226 	struct ifnet *gifp = NULL;
227 	struct ip *ip;
228 	int af;
229 	u_int8_t otos;
230 	int proto;
231 
232 	ip = mtod(m, struct ip *);
233 	proto = ip->ip_p;
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 (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
259 				  ECN_ALLOWED : ECN_NOCARE,
260 				  &otos, &ip->ip_tos) == 0) {
261 			m_freem(m);
262 			return;
263 		}
264 		break;
265 	    }
266 #endif
267 #ifdef INET6
268 	case IPPROTO_IPV6:
269 	    {
270 		struct ip6_hdr *ip6;
271 		u_int8_t itos, oitos;
272 
273 		af = AF_INET6;
274 		if (m->m_len < sizeof(*ip6)) {
275 			m = m_pullup(m, sizeof(*ip6));
276 			if (!m)
277 				return;
278 		}
279 		ip6 = mtod(m, struct ip6_hdr *);
280 		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
281 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
282 				  ECN_ALLOWED : ECN_NOCARE,
283 				  &otos, &itos) == 0) {
284 			m_freem(m);
285 			return;
286 		}
287 		if (itos != oitos) {
288 			ip6->ip6_flow &= ~htonl(0xff << 20);
289 			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
290 		}
291 		break;
292 	    }
293 #endif /* INET6 */
294 	default:
295 		ipstat.ips_nogif++;
296 		m_freem(m);
297 		return;
298 	}
299 	gif_input(m, af, gifp);
300 	return;
301 }
302 
303 /*
304  * validate outer address.
305  */
306 static int
307 gif_validate4(ip, sc, ifp)
308 	const struct ip *ip;
309 	struct gif_softc *sc;
310 	struct ifnet *ifp;
311 {
312 	struct sockaddr_in *src, *dst;
313 	struct in_ifaddr *ia4;
314 
315 	src = (struct sockaddr_in *)sc->gif_psrc;
316 	dst = (struct sockaddr_in *)sc->gif_pdst;
317 
318 	/* check for address match */
319 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
320 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
321 		return 0;
322 
323 	/* martian filters on outer source - NOT done in ip_input! */
324 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
325 		return 0;
326 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
327 	case 0: case 127: case 255:
328 		return 0;
329 	}
330 	/* reject packets with broadcast on source */
331 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
332 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
333 			continue;
334 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
335 			return 0;
336 	}
337 
338 	/* ingress filters on outer source */
339 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
340 		struct sockaddr_in sin;
341 		struct rtentry *rt;
342 
343 		bzero(&sin, sizeof(sin));
344 		sin.sin_family = AF_INET;
345 		sin.sin_len = sizeof(struct sockaddr_in);
346 		sin.sin_addr = ip->ip_src;
347 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
348 		if (!rt || rt->rt_ifp != ifp) {
349 #if 0
350 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
351 			    "due to ingress filter\n", if_name(&sc->gif_if),
352 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
353 #endif
354 			if (rt)
355 				rtfree(rt);
356 			return 0;
357 		}
358 		rtfree(rt);
359 	}
360 
361 	return 32 * 2;
362 }
363 
364 /*
365  * we know that we are in IFF_UP, outer address available, and outer family
366  * matched the physical addr family.  see gif_encapcheck().
367  */
368 int
369 gif_encapcheck4(m, off, proto, arg)
370 	const struct mbuf *m;
371 	int off;
372 	int proto;
373 	void *arg;
374 {
375 	struct ip ip;
376 	struct gif_softc *sc;
377 	struct ifnet *ifp;
378 
379 	/* sanity check done in caller */
380 	sc = (struct gif_softc *)arg;
381 
382 	/* LINTED const cast */
383 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
384 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
385 
386 	return gif_validate4(&ip, sc, ifp);
387 }
388 
389 int
390 in_gif_attach(sc)
391 	struct gif_softc *sc;
392 {
393 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
394 	    &in_gif_protosw, sc);
395 	if (sc->encap_cookie4 == NULL)
396 		return EEXIST;
397 	return 0;
398 }
399 
400 int
401 in_gif_detach(sc)
402 	struct gif_softc *sc;
403 {
404 	int error;
405 
406 	error = encap_detach(sc->encap_cookie4);
407 	if (error == 0)
408 		sc->encap_cookie4 = NULL;
409 	return error;
410 }
411