xref: /freebsd/sys/netinet/in_gif.c (revision 262e143bd46171a6415a5b28af260a5efa2a3db8) 
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 	.pr_type =		SOCK_RAW,
79 	.pr_domain =		&inetdomain,
80 	.pr_protocol =		0/* IPPROTO_IPV[46] */,
81 	.pr_flags =		PR_ATOMIC|PR_ADDR,
82 	.pr_input =		in_gif_input,
83 	.pr_output =		(pr_output_t*)rip_output,
84 	.pr_ctloutput =		rip_ctloutput,
85 	.pr_usrreqs =		&rip_usrreqs
86 };
87 
88 static int ip_gif_ttl = GIF_TTL;
89 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
90 	&ip_gif_ttl,	0, "");
91 
92 int
93 in_gif_output(ifp, family, m)
94 	struct ifnet	*ifp;
95 	int		family;
96 	struct mbuf	*m;
97 {
98 	struct gif_softc *sc = ifp->if_softc;
99 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
100 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
101 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
102 	struct ip iphdr;	/* capsule IP header, host byte ordered */
103 	int proto, error;
104 	u_int8_t tos;
105 
106 	if (sin_src == NULL || sin_dst == NULL ||
107 	    sin_src->sin_family != AF_INET ||
108 	    sin_dst->sin_family != AF_INET) {
109 		m_freem(m);
110 		return EAFNOSUPPORT;
111 	}
112 
113 	switch (family) {
114 #ifdef INET
115 	case AF_INET:
116 	    {
117 		struct ip *ip;
118 
119 		proto = IPPROTO_IPV4;
120 		if (m->m_len < sizeof(*ip)) {
121 			m = m_pullup(m, sizeof(*ip));
122 			if (!m)
123 				return ENOBUFS;
124 		}
125 		ip = mtod(m, struct ip *);
126 		tos = ip->ip_tos;
127 		break;
128 	    }
129 #endif /* INET */
130 #ifdef INET6
131 	case AF_INET6:
132 	    {
133 		struct ip6_hdr *ip6;
134 		proto = IPPROTO_IPV6;
135 		if (m->m_len < sizeof(*ip6)) {
136 			m = m_pullup(m, sizeof(*ip6));
137 			if (!m)
138 				return ENOBUFS;
139 		}
140 		ip6 = mtod(m, struct ip6_hdr *);
141 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
142 		break;
143 	    }
144 #endif /* INET6 */
145 	default:
146 #ifdef DEBUG
147 		printf("in_gif_output: warning: unknown family %d passed\n",
148 			family);
149 #endif
150 		m_freem(m);
151 		return EAFNOSUPPORT;
152 	}
153 
154 	bzero(&iphdr, sizeof(iphdr));
155 	iphdr.ip_src = sin_src->sin_addr;
156 	/* bidirectional configured tunnel mode */
157 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
158 		iphdr.ip_dst = sin_dst->sin_addr;
159 	else {
160 		m_freem(m);
161 		return ENETUNREACH;
162 	}
163 	iphdr.ip_p = proto;
164 	/* version will be set in ip_output() */
165 	iphdr.ip_ttl = ip_gif_ttl;
166 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
167 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
168 		       &iphdr.ip_tos, &tos);
169 
170 	/* prepend new IP header */
171 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
172 	if (m && m->m_len < sizeof(struct ip))
173 		m = m_pullup(m, sizeof(struct ip));
174 	if (m == NULL) {
175 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
176 		return ENOBUFS;
177 	}
178 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
179 
180 	if (dst->sin_family != sin_dst->sin_family ||
181 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
182 		/* cache route doesn't match */
183 		bzero(dst, sizeof(*dst));
184 		dst->sin_family = sin_dst->sin_family;
185 		dst->sin_len = sizeof(struct sockaddr_in);
186 		dst->sin_addr = sin_dst->sin_addr;
187 		if (sc->gif_ro.ro_rt) {
188 			RTFREE(sc->gif_ro.ro_rt);
189 			sc->gif_ro.ro_rt = NULL;
190 		}
191 #if 0
192 		GIF2IFP(sc)->if_mtu = GIF_MTU;
193 #endif
194 	}
195 
196 	if (sc->gif_ro.ro_rt == NULL) {
197 		rtalloc_ign(&sc->gif_ro, 0);
198 		if (sc->gif_ro.ro_rt == NULL) {
199 			m_freem(m);
200 			return ENETUNREACH;
201 		}
202 
203 		/* if it constitutes infinite encapsulation, punt. */
204 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
205 			m_freem(m);
206 			return ENETUNREACH;	/* XXX */
207 		}
208 #if 0
209 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
210 			- sizeof(struct ip);
211 #endif
212 	}
213 
214 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
215 
216 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
217 	    sc->gif_ro.ro_rt != NULL) {
218 		RTFREE(sc->gif_ro.ro_rt);
219 		sc->gif_ro.ro_rt = NULL;
220 	}
221 
222 	return (error);
223 }
224 
225 void
226 in_gif_input(m, off)
227 	struct mbuf *m;
228 	int off;
229 {
230 	struct ifnet *gifp = NULL;
231 	struct gif_softc *sc;
232 	struct ip *ip;
233 	int af;
234 	u_int8_t otos;
235 	int proto;
236 
237 	ip = mtod(m, struct ip *);
238 	proto = ip->ip_p;
239 
240 	sc = (struct gif_softc *)encap_getarg(m);
241 	if (sc == NULL) {
242 		m_freem(m);
243 		ipstat.ips_nogif++;
244 		return;
245 	}
246 
247 	gifp = GIF2IFP(sc);
248 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
249 		m_freem(m);
250 		ipstat.ips_nogif++;
251 		return;
252 	}
253 
254 	otos = ip->ip_tos;
255 	m_adj(m, off);
256 
257 	switch (proto) {
258 #ifdef INET
259 	case IPPROTO_IPV4:
260 	    {
261 		struct ip *ip;
262 		af = AF_INET;
263 		if (m->m_len < sizeof(*ip)) {
264 			m = m_pullup(m, sizeof(*ip));
265 			if (!m)
266 				return;
267 		}
268 		ip = mtod(m, struct ip *);
269 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
270 				  ECN_ALLOWED : ECN_NOCARE,
271 				  &otos, &ip->ip_tos) == 0) {
272 			m_freem(m);
273 			return;
274 		}
275 		break;
276 	    }
277 #endif
278 #ifdef INET6
279 	case IPPROTO_IPV6:
280 	    {
281 		struct ip6_hdr *ip6;
282 		u_int8_t itos, oitos;
283 
284 		af = AF_INET6;
285 		if (m->m_len < sizeof(*ip6)) {
286 			m = m_pullup(m, sizeof(*ip6));
287 			if (!m)
288 				return;
289 		}
290 		ip6 = mtod(m, struct ip6_hdr *);
291 		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
292 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
293 				  ECN_ALLOWED : ECN_NOCARE,
294 				  &otos, &itos) == 0) {
295 			m_freem(m);
296 			return;
297 		}
298 		if (itos != oitos) {
299 			ip6->ip6_flow &= ~htonl(0xff << 20);
300 			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
301 		}
302 		break;
303 	    }
304 #endif /* INET6 */
305 	default:
306 		ipstat.ips_nogif++;
307 		m_freem(m);
308 		return;
309 	}
310 	gif_input(m, af, gifp);
311 	return;
312 }
313 
314 /*
315  * validate outer address.
316  */
317 static int
318 gif_validate4(ip, sc, ifp)
319 	const struct ip *ip;
320 	struct gif_softc *sc;
321 	struct ifnet *ifp;
322 {
323 	struct sockaddr_in *src, *dst;
324 	struct in_ifaddr *ia4;
325 
326 	src = (struct sockaddr_in *)sc->gif_psrc;
327 	dst = (struct sockaddr_in *)sc->gif_pdst;
328 
329 	/* check for address match */
330 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
331 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
332 		return 0;
333 
334 	/* martian filters on outer source - NOT done in ip_input! */
335 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
336 		return 0;
337 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
338 	case 0: case 127: case 255:
339 		return 0;
340 	}
341 	/* reject packets with broadcast on source */
342 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
343 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
344 			continue;
345 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
346 			return 0;
347 	}
348 
349 	/* ingress filters on outer source */
350 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
351 		struct sockaddr_in sin;
352 		struct rtentry *rt;
353 
354 		bzero(&sin, sizeof(sin));
355 		sin.sin_family = AF_INET;
356 		sin.sin_len = sizeof(struct sockaddr_in);
357 		sin.sin_addr = ip->ip_src;
358 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
359 		if (!rt || rt->rt_ifp != ifp) {
360 #if 0
361 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
362 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
363 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
364 #endif
365 			if (rt)
366 				rtfree(rt);
367 			return 0;
368 		}
369 		rtfree(rt);
370 	}
371 
372 	return 32 * 2;
373 }
374 
375 /*
376  * we know that we are in IFF_UP, outer address available, and outer family
377  * matched the physical addr family.  see gif_encapcheck().
378  */
379 int
380 gif_encapcheck4(m, off, proto, arg)
381 	const struct mbuf *m;
382 	int off;
383 	int proto;
384 	void *arg;
385 {
386 	struct ip ip;
387 	struct gif_softc *sc;
388 	struct ifnet *ifp;
389 
390 	/* sanity check done in caller */
391 	sc = (struct gif_softc *)arg;
392 
393 	/* LINTED const cast */
394 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
395 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
396 
397 	return gif_validate4(&ip, sc, ifp);
398 }
399 
400 int
401 in_gif_attach(sc)
402 	struct gif_softc *sc;
403 {
404 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
405 	    &in_gif_protosw, sc);
406 	if (sc->encap_cookie4 == NULL)
407 		return EEXIST;
408 	return 0;
409 }
410 
411 int
412 in_gif_detach(sc)
413 	struct gif_softc *sc;
414 {
415 	int error;
416 
417 	error = encap_detach(sc->encap_cookie4);
418 	if (error == 0)
419 		sc->encap_cookie4 = NULL;
420 	return error;
421 }
422