xref: /freebsd/sys/netinet/in_gif.c (revision 2357939bc239bd5334a169b62313806178dd8f30) 
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 		dst->sin_family = sin_dst->sin_family;
181 		dst->sin_len = sizeof(struct sockaddr_in);
182 		dst->sin_addr = sin_dst->sin_addr;
183 		if (sc->gif_ro.ro_rt) {
184 			RTFREE(sc->gif_ro.ro_rt);
185 			sc->gif_ro.ro_rt = NULL;
186 		}
187 #if 0
188 		sc->gif_if.if_mtu = GIF_MTU;
189 #endif
190 	}
191 
192 	if (sc->gif_ro.ro_rt == NULL) {
193 		rtalloc_ign(&sc->gif_ro, 0);
194 		if (sc->gif_ro.ro_rt == NULL) {
195 			m_freem(m);
196 			return ENETUNREACH;
197 		}
198 
199 		/* if it constitutes infinite encapsulation, punt. */
200 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
201 			m_freem(m);
202 			return ENETUNREACH;	/* XXX */
203 		}
204 #if 0
205 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
206 			- sizeof(struct ip);
207 #endif
208 	}
209 
210 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
211 	return (error);
212 }
213 
214 void
215 in_gif_input(m, off)
216 	struct mbuf *m;
217 	int off;
218 {
219 	struct ifnet *gifp = NULL;
220 	struct ip *ip;
221 	int af;
222 	u_int8_t otos;
223 	int proto;
224 
225 	ip = mtod(m, struct ip *);
226 	proto = ip->ip_p;
227 
228 	gifp = (struct ifnet *)encap_getarg(m);
229 
230 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
231 		m_freem(m);
232 		ipstat.ips_nogif++;
233 		return;
234 	}
235 
236 	otos = ip->ip_tos;
237 	m_adj(m, off);
238 
239 	switch (proto) {
240 #ifdef INET
241 	case IPPROTO_IPV4:
242 	    {
243 		struct ip *ip;
244 		af = AF_INET;
245 		if (m->m_len < sizeof(*ip)) {
246 			m = m_pullup(m, sizeof(*ip));
247 			if (!m)
248 				return;
249 		}
250 		ip = mtod(m, struct ip *);
251 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
252 				  ECN_ALLOWED : ECN_NOCARE,
253 				  &otos, &ip->ip_tos) == 0) {
254 			m_freem(m);
255 			return;
256 		}
257 		break;
258 	    }
259 #endif
260 #ifdef INET6
261 	case IPPROTO_IPV6:
262 	    {
263 		struct ip6_hdr *ip6;
264 		u_int8_t itos, oitos;
265 
266 		af = AF_INET6;
267 		if (m->m_len < sizeof(*ip6)) {
268 			m = m_pullup(m, sizeof(*ip6));
269 			if (!m)
270 				return;
271 		}
272 		ip6 = mtod(m, struct ip6_hdr *);
273 		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
274 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
275 				  ECN_ALLOWED : ECN_NOCARE,
276 				  &otos, &itos) == 0) {
277 			m_freem(m);
278 			return;
279 		}
280 		if (itos != oitos) {
281 			ip6->ip6_flow &= ~htonl(0xff << 20);
282 			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
283 		}
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  * validate outer address.
298  */
299 static int
300 gif_validate4(ip, sc, ifp)
301 	const struct ip *ip;
302 	struct gif_softc *sc;
303 	struct ifnet *ifp;
304 {
305 	struct sockaddr_in *src, *dst;
306 	struct in_ifaddr *ia4;
307 
308 	src = (struct sockaddr_in *)sc->gif_psrc;
309 	dst = (struct sockaddr_in *)sc->gif_pdst;
310 
311 	/* check for address match */
312 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
313 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
314 		return 0;
315 
316 	/* martian filters on outer source - NOT done in ip_input! */
317 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
318 		return 0;
319 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
320 	case 0: case 127: case 255:
321 		return 0;
322 	}
323 	/* reject packets with broadcast on source */
324 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
325 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
326 			continue;
327 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
328 			return 0;
329 	}
330 
331 	/* ingress filters on outer source */
332 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
333 		struct sockaddr_in sin;
334 		struct rtentry *rt;
335 
336 		bzero(&sin, sizeof(sin));
337 		sin.sin_family = AF_INET;
338 		sin.sin_len = sizeof(struct sockaddr_in);
339 		sin.sin_addr = ip->ip_src;
340 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
341 		if (!rt || rt->rt_ifp != ifp) {
342 #if 0
343 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
344 			    "due to ingress filter\n", if_name(&sc->gif_if),
345 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
346 #endif
347 			if (rt)
348 				rtfree(rt);
349 			return 0;
350 		}
351 		rtfree(rt);
352 	}
353 
354 	return 32 * 2;
355 }
356 
357 /*
358  * we know that we are in IFF_UP, outer address available, and outer family
359  * matched the physical addr family.  see gif_encapcheck().
360  */
361 int
362 gif_encapcheck4(m, off, proto, arg)
363 	const struct mbuf *m;
364 	int off;
365 	int proto;
366 	void *arg;
367 {
368 	struct ip ip;
369 	struct gif_softc *sc;
370 	struct ifnet *ifp;
371 
372 	/* sanity check done in caller */
373 	sc = (struct gif_softc *)arg;
374 
375 	/* LINTED const cast */
376 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
377 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
378 
379 	return gif_validate4(&ip, sc, ifp);
380 }
381 
382 int
383 in_gif_attach(sc)
384 	struct gif_softc *sc;
385 {
386 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
387 	    &in_gif_protosw, sc);
388 	if (sc->encap_cookie4 == NULL)
389 		return EEXIST;
390 	return 0;
391 }
392 
393 int
394 in_gif_detach(sc)
395 	struct gif_softc *sc;
396 {
397 	int error;
398 
399 	error = encap_detach(sc->encap_cookie4);
400 	if (error == 0)
401 		sc->encap_cookie4 = NULL;
402 	return error;
403 }
404