xref: /netbsd-src/sys/netinet/in_gif.c (revision ca453df649ce9db45b64d73678ba06cbccf9aa11) 
1 /*	$NetBSD: in_gif.c,v 1.61 2011/07/17 20:54:53 joerg 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 1.61 2011/07/17 20:54:53 joerg 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 <net/net_osdep.h>
71 
72 static int gif_validate4(const struct ip *, struct gif_softc *,
73 	struct ifnet *);
74 
75 #if NGIF > 0
76 int ip_gif_ttl = GIF_TTL;
77 #else
78 int ip_gif_ttl = 0;
79 #endif
80 
81 const struct protosw in_gif_protosw =
82 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
83   in_gif_input, rip_output,	0,		rip_ctloutput,
84   rip_usrreq,
85   0,            0,              0,              0,
86 };
87 
88 int
89 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
90 {
91 	struct rtentry *rt;
92 	struct gif_softc *sc = ifp->if_softc;
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 	union {
99 		struct sockaddr		dst;
100 		struct sockaddr_in	dst4;
101 	} u;
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 		const 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 == NULL)
120 				return ENOBUFS;
121 		}
122 		ip = mtod(m, const struct ip *);
123 		tos = ip->ip_tos;
124 		break;
125 	    }
126 #endif /* INET */
127 #ifdef INET6
128 	case AF_INET6:
129 	    {
130 		const 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, const struct ip6_hdr *);
138 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
139 		break;
140 	    }
141 #endif /* INET6 */
142 #ifdef ISO
143 	case AF_ISO:
144 		proto = IPPROTO_EON;
145 		tos = 0;
146 		break;
147 #endif
148 	default:
149 #ifdef DEBUG
150 		printf("in_gif_output: warning: unknown family %d passed\n",
151 			family);
152 #endif
153 		m_freem(m);
154 		return EAFNOSUPPORT;
155 	}
156 
157 	memset(&iphdr, 0, sizeof(iphdr));
158 	iphdr.ip_src = sin_src->sin_addr;
159 	/* bidirectional configured tunnel mode */
160 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
161 		iphdr.ip_dst = sin_dst->sin_addr;
162 	else {
163 		m_freem(m);
164 		return ENETUNREACH;
165 	}
166 	iphdr.ip_p = proto;
167 	/* version will be set in ip_output() */
168 	iphdr.ip_ttl = ip_gif_ttl;
169 	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
170 	if (ifp->if_flags & IFF_LINK1)
171 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
172 	else
173 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
174 
175 	/* prepend new IP header */
176 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
177 	/* XXX Is m_pullup really necessary after M_PREPEND? */
178 	if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip)))
179 		m = m_pullup(m, sizeof(struct ip));
180 	if (m == NULL)
181 		return ENOBUFS;
182 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
183 
184 	sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0);
185 	if ((rt = rtcache_lookup(&sc->gif_ro, &u.dst)) == NULL) {
186 		m_freem(m);
187 		return ENETUNREACH;
188 	}
189 
190 	/* If the route constitutes infinite encapsulation, punt. */
191 	if (rt->rt_ifp == ifp) {
192 		rtcache_free(&sc->gif_ro);
193 		m_freem(m);
194 		return ENETUNREACH;	/*XXX*/
195 	}
196 
197 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
198 	return (error);
199 }
200 
201 void
202 in_gif_input(struct mbuf *m, ...)
203 {
204 	int off, proto;
205 	struct ifnet *gifp = NULL;
206 	const struct ip *ip;
207 	va_list ap;
208 	int af;
209 	u_int8_t otos;
210 
211 	va_start(ap, m);
212 	off = va_arg(ap, int);
213 	proto = va_arg(ap, int);
214 	va_end(ap);
215 
216 	ip = mtod(m, const struct ip *);
217 
218 	gifp = (struct ifnet *)encap_getarg(m);
219 
220 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
221 		m_freem(m);
222 		ip_statinc(IP_STAT_NOGIF);
223 		return;
224 	}
225 #ifndef GIF_ENCAPCHECK
226 	if (!gif_validate4(ip, gifp->if_softc, m->m_pkthdr.rcvif)) {
227 		m_freem(m);
228 		ip_statinc(IP_STAT_NOGIF);
229 		return;
230 	}
231 #endif
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 *xip;
241 		af = AF_INET;
242 		if (M_UNWRITABLE(m, sizeof(*xip))) {
243 			if ((m = m_pullup(m, sizeof(*xip))) == NULL)
244 				return;
245 		}
246 		xip = mtod(m, struct ip *);
247 		if (gifp->if_flags & IFF_LINK1)
248 			ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
249 		else
250 			ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos);
251 		break;
252 	    }
253 #endif
254 #ifdef INET6
255 	case IPPROTO_IPV6:
256 	    {
257 		struct ip6_hdr *ip6;
258 		u_int8_t itos;
259 		af = AF_INET6;
260 		if (M_UNWRITABLE(m, sizeof(*ip6))) {
261 			if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
262 				return;
263 		}
264 		ip6 = mtod(m, struct ip6_hdr *);
265 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
266 		if (gifp->if_flags & IFF_LINK1)
267 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
268 		else
269 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
270 		ip6->ip6_flow &= ~htonl(0xff << 20);
271 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
272 		break;
273 	    }
274 #endif /* INET6 */
275 #ifdef ISO
276 	case IPPROTO_EON:
277 		af = AF_ISO;
278 		break;
279 #endif
280 	default:
281 		ip_statinc(IP_STAT_NOGIF);
282 		m_freem(m);
283 		return;
284 	}
285 	gif_input(m, af, gifp);
286 	return;
287 }
288 
289 /*
290  * validate outer address.
291  */
292 static int
293 gif_validate4(const struct ip *ip, struct gif_softc *sc, 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(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 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
315 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
316 			continue;
317 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
318 			return 0;
319 	}
320 
321 	/* ingress filters on outer source */
322 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
323 		union {
324 			struct sockaddr sa;
325 			struct sockaddr_in sin;
326 		} u;
327 		struct rtentry *rt;
328 
329 		sockaddr_in_init(&u.sin, &ip->ip_src, 0);
330 		rt = rtalloc1(&u.sa, 0);
331 		if (rt == NULL || rt->rt_ifp != ifp) {
332 #if 0
333 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
334 			    "due to ingress filter\n", if_name(&sc->gif_if),
335 			    (u_int32_t)ntohl(u.sin.sin_addr.s_addr));
336 #endif
337 			if (rt != NULL)
338 				rtfree(rt);
339 			return 0;
340 		}
341 		rtfree(rt);
342 	}
343 
344 	return 32 * 2;
345 }
346 
347 #ifdef GIF_ENCAPCHECK
348 /*
349  * we know that we are in IFF_UP, outer address available, and outer family
350  * matched the physical addr family.  see gif_encapcheck().
351  */
352 int
353 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg)
354 {
355 	struct ip ip;
356 	struct gif_softc *sc;
357 	struct ifnet *ifp;
358 
359 	/* sanity check done in caller */
360 	sc = arg;
361 
362 	m_copydata(m, 0, sizeof(ip), &ip);
363 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
364 
365 	return gif_validate4(&ip, sc, ifp);
366 }
367 #endif
368 
369 int
370 in_gif_attach(struct gif_softc *sc)
371 {
372 #ifndef GIF_ENCAPCHECK
373 	struct sockaddr_in mask4;
374 
375 	memset(&mask4, 0, sizeof(mask4));
376 	mask4.sin_len = sizeof(struct sockaddr_in);
377 	mask4.sin_addr.s_addr = ~0;
378 
379 	if (!sc->gif_psrc || !sc->gif_pdst)
380 		return EINVAL;
381 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
382 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
383 	    (const struct protosw *)&in_gif_protosw, sc);
384 #else
385 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
386 	    &in_gif_protosw, sc);
387 #endif
388 	if (sc->encap_cookie4 == NULL)
389 		return EEXIST;
390 	return 0;
391 }
392 
393 int
394 in_gif_detach(struct gif_softc *sc)
395 {
396 	int error;
397 
398 	error = encap_detach(sc->encap_cookie4);
399 	if (error == 0)
400 		sc->encap_cookie4 = NULL;
401 
402 	rtcache_free(&sc->gif_ro);
403 
404 	return error;
405 }
406