xref: /netbsd-src/sys/netinet/in_gif.c (revision de1dfb1250df962f1ff3a011772cf58e605aed11) 
1 /*	$NetBSD: in_gif.c,v 1.36 2004/04/26 01:31:56 matt 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 1.36 2004/04/26 01:31:56 matt 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 
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 "gif.h"
68 
69 #include <machine/stdarg.h>
70 
71 #include <net/net_osdep.h>
72 
73 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
74 	struct ifnet *));
75 
76 #if NGIF > 0
77 int ip_gif_ttl = GIF_TTL;
78 #else
79 int ip_gif_ttl = 0;
80 #endif
81 
82 const struct protosw in_gif_protosw =
83 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
84   in_gif_input, rip_output,	0,		rip_ctloutput,
85   rip_usrreq,
86   0,            0,              0,              0,
87 };
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 #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 	bzero(&iphdr, 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 	if (m && m->m_len < sizeof(struct ip))
178 		m = m_pullup(m, sizeof(struct ip));
179 	if (m == NULL)
180 		return ENOBUFS;
181 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
182 
183 	if (dst->sin_family != sin_dst->sin_family ||
184 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
185 		/* cache route doesn't match */
186 		bzero(dst, sizeof(*dst));
187 		dst->sin_family = sin_dst->sin_family;
188 		dst->sin_len = sizeof(struct sockaddr_in);
189 		dst->sin_addr = sin_dst->sin_addr;
190 		if (sc->gif_ro.ro_rt) {
191 			RTFREE(sc->gif_ro.ro_rt);
192 			sc->gif_ro.ro_rt = NULL;
193 		}
194 	}
195 
196 	if (sc->gif_ro.ro_rt == NULL) {
197 		rtalloc(&sc->gif_ro);
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 	}
209 
210 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
211 	return (error);
212 }
213 
214 void
215 in_gif_input(struct mbuf *m, ...)
216 {
217 	int off, proto;
218 	struct ifnet *gifp = NULL;
219 	struct ip *ip;
220 	va_list ap;
221 	int af;
222 	u_int8_t otos;
223 
224 	va_start(ap, m);
225 	off = va_arg(ap, int);
226 	proto = va_arg(ap, int);
227 	va_end(ap);
228 
229 	ip = mtod(m, struct ip *);
230 
231 	gifp = (struct ifnet *)encap_getarg(m);
232 
233 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
234 		m_freem(m);
235 		ipstat.ips_nogif++;
236 		return;
237 	}
238 #ifndef GIF_ENCAPCHECK
239 	if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
240 		m_freem(m);
241 		ipstat.ips_nogif++;
242 		return;
243 	}
244 #endif
245 
246 	otos = ip->ip_tos;
247 	m_adj(m, off);
248 
249 	switch (proto) {
250 #ifdef INET
251 	case IPPROTO_IPV4:
252 	    {
253 		struct ip *ip;
254 		af = AF_INET;
255 		if (m->m_len < sizeof(*ip)) {
256 			m = m_pullup(m, sizeof(*ip));
257 			if (!m)
258 				return;
259 		}
260 		ip = mtod(m, struct ip *);
261 		if (gifp->if_flags & IFF_LINK1)
262 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
263 		else
264 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
265 		break;
266 	    }
267 #endif
268 #ifdef INET6
269 	case IPPROTO_IPV6:
270 	    {
271 		struct ip6_hdr *ip6;
272 		u_int8_t itos;
273 		af = AF_INET6;
274 		if (m->m_len < sizeof(*ip6)) {
275 			m = m_pullup(m, sizeof(*ip6));
276 			if (!m)
277 				return;
278 		}
279 		ip6 = mtod(m, struct ip6_hdr *);
280 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
281 		if (gifp->if_flags & IFF_LINK1)
282 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
283 		else
284 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
285 		ip6->ip6_flow &= ~htonl(0xff << 20);
286 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
287 		break;
288 	    }
289 #endif /* INET6 */
290 #ifdef ISO
291 	case IPPROTO_EON:
292 		af = AF_ISO;
293 		break;
294 #endif
295 	default:
296 		ipstat.ips_nogif++;
297 		m_freem(m);
298 		return;
299 	}
300 	gif_input(m, af, gifp);
301 	return;
302 }
303 
304 /*
305  * validate outer address.
306  */
307 static int
308 gif_validate4(ip, sc, ifp)
309 	const struct ip *ip;
310 	struct gif_softc *sc;
311 	struct ifnet *ifp;
312 {
313 	struct sockaddr_in *src, *dst;
314 	struct in_ifaddr *ia4;
315 
316 	src = (struct sockaddr_in *)sc->gif_psrc;
317 	dst = (struct sockaddr_in *)sc->gif_pdst;
318 
319 	/* check for address match */
320 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
321 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
322 		return 0;
323 
324 	/* martian filters on outer source - NOT done in ip_input! */
325 	if (IN_MULTICAST(ip->ip_src.s_addr))
326 		return 0;
327 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
328 	case 0: case 127: case 255:
329 		return 0;
330 	}
331 	/* reject packets with broadcast on source */
332 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
333 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
334 			continue;
335 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
336 			return 0;
337 	}
338 
339 	/* ingress filters on outer source */
340 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
341 		struct sockaddr_in sin;
342 		struct rtentry *rt;
343 
344 		bzero(&sin, sizeof(sin));
345 		sin.sin_family = AF_INET;
346 		sin.sin_len = sizeof(struct sockaddr_in);
347 		sin.sin_addr = ip->ip_src;
348 		rt = rtalloc1((struct sockaddr *)&sin, 0);
349 		if (!rt || rt->rt_ifp != ifp) {
350 #if 0
351 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
352 			    "due to ingress filter\n", if_name(&sc->gif_if),
353 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
354 #endif
355 			if (rt)
356 				rtfree(rt);
357 			return 0;
358 		}
359 		rtfree(rt);
360 	}
361 
362 	return 32 * 2;
363 }
364 
365 #ifdef GIF_ENCAPCHECK
366 /*
367  * we know that we are in IFF_UP, outer address available, and outer family
368  * matched the physical addr family.  see gif_encapcheck().
369  */
370 int
371 gif_encapcheck4(m, off, proto, arg)
372 	const struct mbuf *m;
373 	int off;
374 	int proto;
375 	void *arg;
376 {
377 	struct ip ip;
378 	struct gif_softc *sc;
379 	struct ifnet *ifp;
380 
381 	/* sanity check done in caller */
382 	sc = (struct gif_softc *)arg;
383 
384 	/* LINTED const cast */
385 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
386 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
387 
388 	return gif_validate4(&ip, sc, ifp);
389 }
390 #endif
391 
392 int
393 in_gif_attach(sc)
394 	struct gif_softc *sc;
395 {
396 #ifndef GIF_ENCAPCHECK
397 	struct sockaddr_in mask4;
398 
399 	bzero(&mask4, sizeof(mask4));
400 	mask4.sin_len = sizeof(struct sockaddr_in);
401 	mask4.sin_addr.s_addr = ~0;
402 
403 	if (!sc->gif_psrc || !sc->gif_pdst)
404 		return EINVAL;
405 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
406 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
407 	    (struct protosw *)&in_gif_protosw, sc);
408 #else
409 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
410 	    &in_gif_protosw, sc);
411 #endif
412 	if (sc->encap_cookie4 == NULL)
413 		return EEXIST;
414 	return 0;
415 }
416 
417 int
418 in_gif_detach(sc)
419 	struct gif_softc *sc;
420 {
421 	int error;
422 
423 	error = encap_detach(sc->encap_cookie4);
424 	if (error == 0)
425 		sc->encap_cookie4 = NULL;
426 	return error;
427 }
428