xref: /dragonfly/sys/netinet/in_gif.c (revision 9c600e7d) 
1 /*	$FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $	*/
2 /*	$DragonFly: src/sys/netinet/in_gif.c,v 1.3 2003/06/23 17:55:46 dillon Exp $	*/
3 /*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $	*/
4 
5 /*
6  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. Neither the name of the project nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
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 #include <net/if_gif.h>
66 
67 #include <net/net_osdep.h>
68 
69 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
70 	struct ifnet *));
71 
72 extern  struct domain inetdomain;
73 struct protosw in_gif_protosw =
74 { SOCK_RAW,	&inetdomain,	0/*IPPROTO_IPV[46]*/,	PR_ATOMIC|PR_ADDR,
75   in_gif_input, rip_output,	0,	rip_ctloutput,
76   0,
77   0,		0,		0,		0,
78   &rip_usrreqs
79 };
80 
81 int ip_gif_ttl = GIF_TTL;
82 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
83 	&ip_gif_ttl,	0, "");
84 
85 int
86 in_gif_output(ifp, family, m)
87 	struct ifnet	*ifp;
88 	int		family;
89 	struct mbuf	*m;
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, NULL);
209 	return(error);
210 }
211 
212 void
213 in_gif_input(m, off, proto)
214 	struct mbuf *m;
215 	int off;
216 	int proto;
217 {
218 	struct ifnet *gifp = NULL;
219 	struct ip *ip;
220 	int af;
221 	u_int8_t otos;
222 
223 	ip = mtod(m, struct ip *);
224 
225 	gifp = (struct ifnet *)encap_getarg(m);
226 
227 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
228 		m_freem(m);
229 		ipstat.ips_nogif++;
230 		return;
231 	}
232 
233 	otos = ip->ip_tos;
234 	m_adj(m, off);
235 
236 	switch (proto) {
237 #ifdef INET
238 	case IPPROTO_IPV4:
239 	    {
240 		struct ip *ip;
241 		af = AF_INET;
242 		if (m->m_len < sizeof(*ip)) {
243 			m = m_pullup(m, sizeof(*ip));
244 			if (!m)
245 				return;
246 		}
247 		ip = mtod(m, struct ip *);
248 		if (gifp->if_flags & IFF_LINK1)
249 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
250 		else
251 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
252 		break;
253 	    }
254 #endif
255 #ifdef INET6
256 	case IPPROTO_IPV6:
257 	    {
258 		struct ip6_hdr *ip6;
259 		u_int8_t itos;
260 		af = AF_INET6;
261 		if (m->m_len < sizeof(*ip6)) {
262 			m = m_pullup(m, sizeof(*ip6));
263 			if (!m)
264 				return;
265 		}
266 		ip6 = mtod(m, struct ip6_hdr *);
267 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
268 		if (gifp->if_flags & IFF_LINK1)
269 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
270 		else
271 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
272 		ip6->ip6_flow &= ~htonl(0xff << 20);
273 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
274 		break;
275 	    }
276 #endif /* INET6 */
277 	default:
278 		ipstat.ips_nogif++;
279 		m_freem(m);
280 		return;
281 	}
282 	gif_input(m, af, gifp);
283 	return;
284 }
285 
286 /*
287  * validate outer address.
288  */
289 static int
290 gif_validate4(ip, sc, ifp)
291 	const struct ip *ip;
292 	struct gif_softc *sc;
293 	struct ifnet *ifp;
294 {
295 	struct sockaddr_in *src, *dst;
296 	struct in_ifaddr *ia4;
297 
298 	src = (struct sockaddr_in *)sc->gif_psrc;
299 	dst = (struct sockaddr_in *)sc->gif_pdst;
300 
301 	/* check for address match */
302 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
303 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
304 		return 0;
305 
306 	/* martian filters on outer source - NOT done in ip_input! */
307 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
308 		return 0;
309 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
310 	case 0: case 127: case 255:
311 		return 0;
312 	}
313 	/* reject packets with broadcast on source */
314 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
315 	     ia4 = TAILQ_NEXT(ia4, ia_link))
316 	{
317 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
318 			continue;
319 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
320 			return 0;
321 	}
322 
323 	/* ingress filters on outer source */
324 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
325 		struct sockaddr_in sin;
326 		struct rtentry *rt;
327 
328 		bzero(&sin, sizeof(sin));
329 		sin.sin_family = AF_INET;
330 		sin.sin_len = sizeof(struct sockaddr_in);
331 		sin.sin_addr = ip->ip_src;
332 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
333 		if (!rt || rt->rt_ifp != ifp) {
334 #if 0
335 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
336 			    "due to ingress filter\n", if_name(&sc->gif_if),
337 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
338 #endif
339 			if (rt)
340 				rtfree(rt);
341 			return 0;
342 		}
343 		rtfree(rt);
344 	}
345 
346 	return 32 * 2;
347 }
348 
349 /*
350  * we know that we are in IFF_UP, outer address available, and outer family
351  * matched the physical addr family.  see gif_encapcheck().
352  */
353 int
354 gif_encapcheck4(m, off, proto, arg)
355 	const struct mbuf *m;
356 	int off;
357 	int proto;
358 	void *arg;
359 {
360 	struct ip ip;
361 	struct gif_softc *sc;
362 	struct ifnet *ifp;
363 
364 	/* sanity check done in caller */
365 	sc = (struct gif_softc *)arg;
366 
367 	/* LINTED const cast */
368 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
369 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
370 
371 	return gif_validate4(&ip, sc, ifp);
372 }
373 
374 int
375 in_gif_attach(sc)
376 	struct gif_softc *sc;
377 {
378 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
379 	    &in_gif_protosw, sc);
380 	if (sc->encap_cookie4 == NULL)
381 		return EEXIST;
382 	return 0;
383 }
384 
385 int
386 in_gif_detach(sc)
387 	struct gif_softc *sc;
388 {
389 	int error;
390 
391 	error = encap_detach(sc->encap_cookie4);
392 	if (error == 0)
393 		sc->encap_cookie4 = NULL;
394 	return error;
395 }
396