xref: /netbsd/sys/netinet/in_gif.c (revision bf9ec67e) 
1 /*	$NetBSD: in_gif.c,v 1.26 2001/12/21 03:21:51 itojun 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 1.26 2001/12/21 03:21:51 itojun Exp $");
35 
36 #include "opt_inet.h"
37 #include "opt_iso.h"
38 
39 /* define it if you want to use encap_attach_func (it helps *BSD merge) */
40 #define USE_ENCAPCHECK
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/socket.h>
45 #include <sys/sockio.h>
46 #include <sys/mbuf.h>
47 #include <sys/errno.h>
48 #include <sys/ioctl.h>
49 #include <sys/syslog.h>
50 #include <sys/protosw.h>
51 
52 #include <net/if.h>
53 #include <net/route.h>
54 
55 #include <netinet/in.h>
56 #include <netinet/in_systm.h>
57 #include <netinet/ip.h>
58 #include <netinet/ip_var.h>
59 #include <netinet/in_gif.h>
60 #include <netinet/in_var.h>
61 #include <netinet/ip_encap.h>
62 #include <netinet/ip_ecn.h>
63 
64 #ifdef INET6
65 #include <netinet/ip6.h>
66 #endif
67 
68 #include <net/if_gif.h>
69 
70 #include "gif.h"
71 
72 #include <machine/stdarg.h>
73 
74 #include <net/net_osdep.h>
75 
76 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
77 	struct ifnet *));
78 
79 #if NGIF > 0
80 int ip_gif_ttl = GIF_TTL;
81 #else
82 int ip_gif_ttl = 0;
83 #endif
84 
85 extern struct domain inetdomain;
86 struct protosw in_gif_protosw =
87 { SOCK_RAW,	&inetdomain,	0/* IPPROTO_IPV[46] */,	PR_ATOMIC|PR_ADDR,
88   in_gif_input, rip_output,	0,		rip_ctloutput,
89   rip_usrreq,
90   0,            0,              0,              0,
91 };
92 
93 int
94 in_gif_output(ifp, family, m)
95 	struct ifnet	*ifp;
96 	int		family;
97 	struct mbuf	*m;
98 {
99 	struct gif_softc *sc = (struct gif_softc*)ifp;
100 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
101 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
102 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
103 	struct ip iphdr;	/* capsule IP header, host byte ordered */
104 	int proto, error;
105 	u_int8_t tos;
106 
107 	if (sin_src == NULL || sin_dst == NULL ||
108 	    sin_src->sin_family != AF_INET ||
109 	    sin_dst->sin_family != AF_INET) {
110 		m_freem(m);
111 		return EAFNOSUPPORT;
112 	}
113 
114 	switch (family) {
115 #ifdef INET
116 	case AF_INET:
117 	    {
118 		struct ip *ip;
119 
120 		proto = IPPROTO_IPV4;
121 		if (m->m_len < sizeof(*ip)) {
122 			m = m_pullup(m, sizeof(*ip));
123 			if (!m)
124 				return ENOBUFS;
125 		}
126 		ip = mtod(m, struct ip *);
127 		tos = ip->ip_tos;
128 		break;
129 	    }
130 #endif /* INET */
131 #ifdef INET6
132 	case AF_INET6:
133 	    {
134 		struct ip6_hdr *ip6;
135 		proto = IPPROTO_IPV6;
136 		if (m->m_len < sizeof(*ip6)) {
137 			m = m_pullup(m, sizeof(*ip6));
138 			if (!m)
139 				return ENOBUFS;
140 		}
141 		ip6 = mtod(m, struct ip6_hdr *);
142 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
143 		break;
144 	    }
145 #endif /* INET6 */
146 #ifdef ISO
147 	case AF_ISO:
148 		proto = IPPROTO_EON;
149 		tos = 0;
150 		break;
151 #endif
152 	default:
153 #ifdef DEBUG
154 		printf("in_gif_output: warning: unknown family %d passed\n",
155 			family);
156 #endif
157 		m_freem(m);
158 		return EAFNOSUPPORT;
159 	}
160 
161 	bzero(&iphdr, sizeof(iphdr));
162 	iphdr.ip_src = sin_src->sin_addr;
163 	/* bidirectional configured tunnel mode */
164 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
165 		iphdr.ip_dst = sin_dst->sin_addr;
166 	else {
167 		m_freem(m);
168 		return ENETUNREACH;
169 	}
170 	iphdr.ip_p = proto;
171 	/* version will be set in ip_output() */
172 	iphdr.ip_ttl = ip_gif_ttl;
173 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
174 	if (ifp->if_flags & IFF_LINK1)
175 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
176 	else
177 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
178 
179 	/* prepend new IP header */
180 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
181 	if (m && m->m_len < sizeof(struct ip))
182 		m = m_pullup(m, sizeof(struct ip));
183 	if (m == NULL)
184 		return ENOBUFS;
185 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
186 
187 	if (dst->sin_family != sin_dst->sin_family ||
188 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
189 		/* cache route doesn't match */
190 		dst->sin_family = sin_dst->sin_family;
191 		dst->sin_len = sizeof(struct sockaddr_in);
192 		dst->sin_addr = sin_dst->sin_addr;
193 		if (sc->gif_ro.ro_rt) {
194 			RTFREE(sc->gif_ro.ro_rt);
195 			sc->gif_ro.ro_rt = NULL;
196 		}
197 	}
198 
199 	if (sc->gif_ro.ro_rt == NULL) {
200 		rtalloc(&sc->gif_ro);
201 		if (sc->gif_ro.ro_rt == NULL) {
202 			m_freem(m);
203 			return ENETUNREACH;
204 		}
205 
206 		/* if it constitutes infinite encapsulation, punt. */
207 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
208 			m_freem(m);
209 			return ENETUNREACH;	/*XXX*/
210 		}
211 	}
212 
213 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL);
214 	return(error);
215 }
216 
217 void
218 #if __STDC__
219 in_gif_input(struct mbuf *m, ...)
220 #else
221 in_gif_input(m, va_alist)
222 	struct mbuf *m;
223 	va_dcl
224 #endif
225 {
226 	int off, proto;
227 	struct ifnet *gifp = NULL;
228 	struct ip *ip;
229 	va_list ap;
230 	int af;
231 	u_int8_t otos;
232 
233 	va_start(ap, m);
234 	off = va_arg(ap, int);
235 	proto = va_arg(ap, int);
236 	va_end(ap);
237 
238 	ip = mtod(m, struct ip *);
239 
240 	gifp = (struct ifnet *)encap_getarg(m);
241 
242 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
243 		m_freem(m);
244 		ipstat.ips_nogif++;
245 		return;
246 	}
247 #ifndef USE_ENCAPCHECK
248 	if (!gif_validate4(ip, (struct gif_softc *)gifp, m->m_pkthdr.rcvif)) {
249 		m_freem(m);
250 		ipstat.ips_nogif++;
251 		return;
252 	}
253 #endif
254 
255 	otos = ip->ip_tos;
256 	m_adj(m, off);
257 
258 	switch (proto) {
259 #ifdef INET
260 	case IPPROTO_IPV4:
261 	    {
262 		struct ip *ip;
263 		af = AF_INET;
264 		if (m->m_len < sizeof(*ip)) {
265 			m = m_pullup(m, sizeof(*ip));
266 			if (!m)
267 				return;
268 		}
269 		ip = mtod(m, struct ip *);
270 		if (gifp->if_flags & IFF_LINK1)
271 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
272 		else
273 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->ip_tos);
274 		break;
275 	    }
276 #endif
277 #ifdef INET6
278 	case IPPROTO_IPV6:
279 	    {
280 		struct ip6_hdr *ip6;
281 		u_int8_t itos;
282 		af = AF_INET6;
283 		if (m->m_len < sizeof(*ip6)) {
284 			m = m_pullup(m, sizeof(*ip6));
285 			if (!m)
286 				return;
287 		}
288 		ip6 = mtod(m, struct ip6_hdr *);
289 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
290 		if (gifp->if_flags & IFF_LINK1)
291 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
292 		else
293 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
294 		ip6->ip6_flow &= ~htonl(0xff << 20);
295 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
296 		break;
297 	    }
298 #endif /* INET6 */
299 #ifdef ISO
300 	case IPPROTO_EON:
301 		af = AF_ISO;
302 		break;
303 #endif
304 	default:
305 		ipstat.ips_nogif++;
306 		m_freem(m);
307 		return;
308 	}
309 	gif_input(m, af, gifp);
310 	return;
311 }
312 
313 /*
314  * validate outer address.
315  */
316 static int
317 gif_validate4(ip, sc, ifp)
318 	const struct ip *ip;
319 	struct gif_softc *sc;
320 	struct ifnet *ifp;
321 {
322 	struct sockaddr_in *src, *dst;
323 	struct in_ifaddr *ia4;
324 
325 	src = (struct sockaddr_in *)sc->gif_psrc;
326 	dst = (struct sockaddr_in *)sc->gif_pdst;
327 
328 	/* check for address match */
329 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
330 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
331 		return 0;
332 
333 	/* martian filters on outer source - NOT done in ip_input! */
334 	if (IN_MULTICAST(ip->ip_src.s_addr))
335 		return 0;
336 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
337 	case 0: case 127: case 255:
338 		return 0;
339 	}
340 	/* reject packets with broadcast on source */
341 	TAILQ_FOREACH(ia4, &in_ifaddr, ia_list) {
342 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
343 			continue;
344 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
345 			return 0;
346 	}
347 
348 	/* ingress filters on outer source */
349 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
350 		struct sockaddr_in sin;
351 		struct rtentry *rt;
352 
353 		bzero(&sin, sizeof(sin));
354 		sin.sin_family = AF_INET;
355 		sin.sin_len = sizeof(struct sockaddr_in);
356 		sin.sin_addr = ip->ip_src;
357 		rt = rtalloc1((struct sockaddr *)&sin, 0);
358 		if (!rt || rt->rt_ifp != ifp) {
359 #if 0
360 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
361 			    "due to ingress filter\n", if_name(&sc->gif_if),
362 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
363 #endif
364 			if (rt)
365 				rtfree(rt);
366 			return 0;
367 		}
368 		rtfree(rt);
369 	}
370 
371 	return 32 * 2;
372 }
373 
374 /*
375  * we know that we are in IFF_UP, outer address available, and outer family
376  * matched the physical addr family.  see gif_encapcheck().
377  */
378 int
379 gif_encapcheck4(m, off, proto, arg)
380 	const struct mbuf *m;
381 	int off;
382 	int proto;
383 	void *arg;
384 {
385 	struct ip ip;
386 	struct gif_softc *sc;
387 	struct ifnet *ifp;
388 
389 	/* sanity check done in caller */
390 	sc = (struct gif_softc *)arg;
391 
392 	/* LINTED const cast */
393 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
394 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
395 
396 	return gif_validate4(&ip, sc, ifp);
397 }
398 
399 int
400 in_gif_attach(sc)
401 	struct gif_softc *sc;
402 {
403 #ifndef USE_ENCAPCHECK
404 	struct sockaddr_in mask4;
405 
406 	bzero(&mask4, sizeof(mask4));
407 	mask4.sin_len = sizeof(struct sockaddr_in);
408 	mask4.sin_addr.s_addr = ~0;
409 
410 	if (!sc->gif_psrc || !sc->gif_pdst)
411 		return EINVAL;
412 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
413 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
414 	    (struct protosw *)&in_gif_protosw, sc);
415 #else
416 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
417 	    &in_gif_protosw, sc);
418 #endif
419 	if (sc->encap_cookie4 == NULL)
420 		return EEXIST;
421 	return 0;
422 }
423 
424 int
425 in_gif_detach(sc)
426 	struct gif_softc *sc;
427 {
428 	int error;
429 
430 	error = encap_detach(sc->encap_cookie4);
431 	if (error == 0)
432 		sc->encap_cookie4 = NULL;
433 	return error;
434 }
435