xref: /netbsd-src/sys/netinet/in_gif.c (revision 8b0f9554ff8762542c4defc4f70e1eb76fb508fa) 
1 /*	$NetBSD: in_gif.c,v 1.56 2007/05/02 20:40:24 dyoung Exp $	*/
2 /*	$KAME: in_gif.c,v 1.66 2001/07/29 04:46:09 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 <sys/cdefs.h>
34 __KERNEL_RCSID(0, "$NetBSD: in_gif.c,v 1.56 2007/05/02 20:40:24 dyoung Exp $");
35 
36 #include "opt_inet.h"
37 #include "opt_iso.h"
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/socket.h>
42 #include <sys/sockio.h>
43 #include <sys/mbuf.h>
44 #include <sys/errno.h>
45 #include <sys/ioctl.h>
46 #include <sys/syslog.h>
47 #include <sys/protosw.h>
48 #include <sys/kernel.h>
49 
50 #include <net/if.h>
51 #include <net/route.h>
52 
53 #include <netinet/in.h>
54 #include <netinet/in_systm.h>
55 #include <netinet/ip.h>
56 #include <netinet/ip_var.h>
57 #include <netinet/in_gif.h>
58 #include <netinet/in_var.h>
59 #include <netinet/ip_encap.h>
60 #include <netinet/ip_ecn.h>
61 
62 #ifdef INET6
63 #include <netinet/ip6.h>
64 #endif
65 
66 #include <net/if_gif.h>
67 
68 #include "gif.h"
69 
70 #include <machine/stdarg.h>
71 
72 #include <net/net_osdep.h>
73 
74 static int gif_validate4(const struct ip *, struct gif_softc *,
75 	struct ifnet *);
76 
77 #if NGIF > 0
78 int ip_gif_ttl = GIF_TTL;
79 #else
80 int ip_gif_ttl = 0;
81 #endif
82 
83 const struct protosw in_gif_protosw =
84 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
85   in_gif_input, rip_output,	0,		rip_ctloutput,
86   rip_usrreq,
87   0,            0,              0,              0,
88 };
89 
90 int
91 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
92 {
93 	struct gif_softc *sc = (struct gif_softc*)ifp;
94 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
95 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
96 	struct ip iphdr;	/* capsule IP header, host byte ordered */
97 	int proto, error;
98 	u_int8_t tos;
99 	union {
100 		struct sockaddr		dst;
101 		struct sockaddr_in	dst4;
102 	} u;
103 
104 	if (sin_src == NULL || sin_dst == NULL ||
105 	    sin_src->sin_family != AF_INET ||
106 	    sin_dst->sin_family != AF_INET) {
107 		m_freem(m);
108 		return EAFNOSUPPORT;
109 	}
110 
111 	switch (family) {
112 #ifdef INET
113 	case AF_INET:
114 	    {
115 		const struct ip *ip;
116 
117 		proto = IPPROTO_IPV4;
118 		if (m->m_len < sizeof(*ip)) {
119 			m = m_pullup(m, sizeof(*ip));
120 			if (m == NULL)
121 				return ENOBUFS;
122 		}
123 		ip = mtod(m, const struct ip *);
124 		tos = ip->ip_tos;
125 		break;
126 	    }
127 #endif /* INET */
128 #ifdef INET6
129 	case AF_INET6:
130 	    {
131 		const struct ip6_hdr *ip6;
132 		proto = IPPROTO_IPV6;
133 		if (m->m_len < sizeof(*ip6)) {
134 			m = m_pullup(m, sizeof(*ip6));
135 			if (!m)
136 				return ENOBUFS;
137 		}
138 		ip6 = mtod(m, const struct ip6_hdr *);
139 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
140 		break;
141 	    }
142 #endif /* INET6 */
143 #ifdef ISO
144 	case AF_ISO:
145 		proto = IPPROTO_EON;
146 		tos = 0;
147 		break;
148 #endif
149 	default:
150 #ifdef DEBUG
151 		printf("in_gif_output: warning: unknown family %d passed\n",
152 			family);
153 #endif
154 		m_freem(m);
155 		return EAFNOSUPPORT;
156 	}
157 
158 	bzero(&iphdr, sizeof(iphdr));
159 	iphdr.ip_src = sin_src->sin_addr;
160 	/* bidirectional configured tunnel mode */
161 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
162 		iphdr.ip_dst = sin_dst->sin_addr;
163 	else {
164 		m_freem(m);
165 		return ENETUNREACH;
166 	}
167 	iphdr.ip_p = proto;
168 	/* version will be set in ip_output() */
169 	iphdr.ip_ttl = ip_gif_ttl;
170 	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
171 	if (ifp->if_flags & IFF_LINK1)
172 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
173 	else
174 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
175 
176 	/* prepend new IP header */
177 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
178 	/* XXX Is m_pullup really necessary after M_PREPEND? */
179 	if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip)))
180 		m = m_pullup(m, sizeof(struct ip));
181 	if (m == NULL)
182 		return ENOBUFS;
183 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
184 
185 	sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0);
186 	if (rtcache_lookup(&sc->gif_ro, &u.dst) == NULL) {
187 		m_freem(m);
188 		return ENETUNREACH;
189 	}
190 
191 	/* If the route constitutes infinite encapsulation, punt. */
192 	if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
193 		rtcache_free(&sc->gif_ro);
194 		m_freem(m);
195 		return ENETUNREACH;	/*XXX*/
196 	}
197 
198 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
199 	return (error);
200 }
201 
202 void
203 in_gif_input(struct mbuf *m, ...)
204 {
205 	int off, proto;
206 	struct ifnet *gifp = NULL;
207 	const struct ip *ip;
208 	va_list ap;
209 	int af;
210 	u_int8_t otos;
211 
212 	va_start(ap, m);
213 	off = va_arg(ap, int);
214 	proto = va_arg(ap, int);
215 	va_end(ap);
216 
217 	ip = mtod(m, const struct ip *);
218 
219 	gifp = (struct ifnet *)encap_getarg(m);
220 
221 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
222 		m_freem(m);
223 		ipstat.ips_nogif++;
224 		return;
225 	}
226 #ifndef GIF_ENCAPCHECK
227 	if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
228 		m_freem(m);
229 		ipstat.ips_nogif++;
230 		return;
231 	}
232 #endif
233 
234 	otos = ip->ip_tos;
235 	m_adj(m, off);
236 
237 	switch (proto) {
238 #ifdef INET
239 	case IPPROTO_IPV4:
240 	    {
241 		struct ip *xip;
242 		af = AF_INET;
243 		if (M_UNWRITABLE(m, sizeof(*xip))) {
244 			if ((m = m_pullup(m, sizeof(*xip))) == NULL)
245 				return;
246 		}
247 		xip = mtod(m, struct ip *);
248 		if (gifp->if_flags & IFF_LINK1)
249 			ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
250 		else
251 			ip_ecn_egress(ECN_NOCARE, &otos, &xip->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_UNWRITABLE(m, sizeof(*ip6))) {
262 			if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
263 				return;
264 		}
265 		ip6 = mtod(m, struct ip6_hdr *);
266 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
267 		if (gifp->if_flags & IFF_LINK1)
268 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
269 		else
270 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
271 		ip6->ip6_flow &= ~htonl(0xff << 20);
272 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
273 		break;
274 	    }
275 #endif /* INET6 */
276 #ifdef ISO
277 	case IPPROTO_EON:
278 		af = AF_ISO;
279 		break;
280 #endif
281 	default:
282 		ipstat.ips_nogif++;
283 		m_freem(m);
284 		return;
285 	}
286 	gif_input(m, af, gifp);
287 	return;
288 }
289 
290 /*
291  * validate outer address.
292  */
293 static int
294 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
295 {
296 	struct sockaddr_in *src, *dst;
297 	struct in_ifaddr *ia4;
298 
299 	src = (struct sockaddr_in *)sc->gif_psrc;
300 	dst = (struct sockaddr_in *)sc->gif_pdst;
301 
302 	/* check for address match */
303 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
304 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
305 		return 0;
306 
307 	/* martian filters on outer source - NOT done in ip_input! */
308 	if (IN_MULTICAST(ip->ip_src.s_addr))
309 		return 0;
310 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
311 	case 0: case 127: case 255:
312 		return 0;
313 	}
314 	/* reject packets with broadcast on source */
315 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
316 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
317 			continue;
318 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
319 			return 0;
320 	}
321 
322 	/* ingress filters on outer source */
323 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
324 		struct sockaddr_in sin;
325 		struct rtentry *rt;
326 
327 		bzero(&sin, sizeof(sin));
328 		sin.sin_family = AF_INET;
329 		sin.sin_len = sizeof(struct sockaddr_in);
330 		sin.sin_addr = ip->ip_src;
331 		rt = rtalloc1((struct sockaddr *)&sin, 0);
332 		if (!rt || rt->rt_ifp != ifp) {
333 #if 0
334 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
335 			    "due to ingress filter\n", if_name(&sc->gif_if),
336 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
337 #endif
338 			if (rt)
339 				rtfree(rt);
340 			return 0;
341 		}
342 		rtfree(rt);
343 	}
344 
345 	return 32 * 2;
346 }
347 
348 #ifdef GIF_ENCAPCHECK
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(struct mbuf *m, int off, int proto, void *arg)
355 {
356 	struct ip ip;
357 	struct gif_softc *sc;
358 	struct ifnet *ifp;
359 
360 	/* sanity check done in caller */
361 	sc = (struct gif_softc *)arg;
362 
363 	m_copydata(m, 0, sizeof(ip), (void *)&ip);
364 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
365 
366 	return gif_validate4(&ip, sc, ifp);
367 }
368 #endif
369 
370 int
371 in_gif_attach(struct gif_softc *sc)
372 {
373 #ifndef GIF_ENCAPCHECK
374 	struct sockaddr_in mask4;
375 
376 	bzero(&mask4, sizeof(mask4));
377 	mask4.sin_len = sizeof(struct sockaddr_in);
378 	mask4.sin_addr.s_addr = ~0;
379 
380 	if (!sc->gif_psrc || !sc->gif_pdst)
381 		return EINVAL;
382 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
383 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
384 	    (const struct protosw *)&in_gif_protosw, sc);
385 #else
386 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
387 	    &in_gif_protosw, sc);
388 #endif
389 	if (sc->encap_cookie4 == NULL)
390 		return EEXIST;
391 	return 0;
392 }
393 
394 int
395 in_gif_detach(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 
403 	rtcache_free(&sc->gif_ro);
404 
405 	return error;
406 }
407