xref: /netbsd-src/sys/netinet/in_gif.c (revision 2e2322c9c07009df921d11b1268f8506affbb8ba) 
1 /*	$NetBSD: in_gif.c,v 1.86 2016/12/14 11:19:15 knakahara 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 1.86 2016/12/14 11:19:15 knakahara Exp $");
35 
36 #ifdef _KERNEL_OPT
37 #include "opt_inet.h"
38 #endif
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/socket.h>
43 #include <sys/sockio.h>
44 #include <sys/mbuf.h>
45 #include <sys/errno.h>
46 #include <sys/ioctl.h>
47 #include <sys/syslog.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 <net/net_osdep.h>
69 
70 static int gif_validate4(const struct ip *, struct gif_softc *,
71 	struct ifnet *);
72 
73 int ip_gif_ttl = GIF_TTL;
74 
75 static const struct encapsw in_gif_encapsw = {
76 	.encapsw4 = {
77 		.pr_input	= in_gif_input,
78 		.pr_ctlinput	= NULL,
79 	}
80 };
81 
82 int
83 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
84 {
85 	struct rtentry *rt;
86 	struct route *ro;
87 	struct gif_softc *sc = ifp->if_softc;
88 	struct sockaddr_in *sin_src = satosin(sc->gif_psrc);
89 	struct sockaddr_in *sin_dst = satosin(sc->gif_pdst);
90 	struct ip iphdr;	/* capsule IP header, host byte ordered */
91 	int proto, error;
92 	u_int8_t tos;
93 	union {
94 		struct sockaddr		dst;
95 		struct sockaddr_in	dst4;
96 	} u;
97 
98 	if (sin_src == NULL || sin_dst == NULL ||
99 	    sin_src->sin_family != AF_INET ||
100 	    sin_dst->sin_family != AF_INET) {
101 		m_freem(m);
102 		return EAFNOSUPPORT;
103 	}
104 
105 	switch (family) {
106 #ifdef INET
107 	case AF_INET:
108 	    {
109 		const struct ip *ip;
110 
111 		proto = IPPROTO_IPV4;
112 		if (m->m_len < sizeof(*ip)) {
113 			m = m_pullup(m, sizeof(*ip));
114 			if (m == NULL)
115 				return ENOBUFS;
116 		}
117 		ip = mtod(m, const struct ip *);
118 		tos = ip->ip_tos;
119 		break;
120 	    }
121 #endif /* INET */
122 #ifdef INET6
123 	case AF_INET6:
124 	    {
125 		const struct ip6_hdr *ip6;
126 		proto = IPPROTO_IPV6;
127 		if (m->m_len < sizeof(*ip6)) {
128 			m = m_pullup(m, sizeof(*ip6));
129 			if (m == NULL)
130 				return ENOBUFS;
131 		}
132 		ip6 = mtod(m, const struct ip6_hdr *);
133 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
134 		break;
135 	    }
136 #endif /* INET6 */
137 	default:
138 #ifdef DEBUG
139 		printf("in_gif_output: warning: unknown family %d passed\n",
140 			family);
141 #endif
142 		m_freem(m);
143 		return EAFNOSUPPORT;
144 	}
145 
146 	memset(&iphdr, 0, sizeof(iphdr));
147 	iphdr.ip_src = sin_src->sin_addr;
148 	/* bidirectional configured tunnel mode */
149 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
150 		iphdr.ip_dst = sin_dst->sin_addr;
151 	else {
152 		m_freem(m);
153 		return ENETUNREACH;
154 	}
155 	iphdr.ip_p = proto;
156 	/* version will be set in ip_output() */
157 	iphdr.ip_ttl = ip_gif_ttl;
158 	iphdr.ip_len = htons(m->m_pkthdr.len + sizeof(struct ip));
159 	if (ifp->if_flags & IFF_LINK1)
160 		ip_ecn_ingress(ECN_ALLOWED, &iphdr.ip_tos, &tos);
161 	else
162 		ip_ecn_ingress(ECN_NOCARE, &iphdr.ip_tos, &tos);
163 
164 	/* prepend new IP header */
165 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
166 	/* XXX Is m_pullup really necessary after M_PREPEND? */
167 	if (m != NULL && M_UNWRITABLE(m, sizeof(struct ip)))
168 		m = m_pullup(m, sizeof(struct ip));
169 	if (m == NULL)
170 		return ENOBUFS;
171 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
172 
173 	sockaddr_in_init(&u.dst4, &sin_dst->sin_addr, 0);
174 
175 	ro = percpu_getref(sc->gif_ro_percpu);
176 	if ((rt = rtcache_lookup(ro, &u.dst)) == NULL) {
177 		percpu_putref(sc->gif_ro_percpu);
178 		m_freem(m);
179 		return ENETUNREACH;
180 	}
181 
182 	/* If the route constitutes infinite encapsulation, punt. */
183 	if (rt->rt_ifp == ifp) {
184 		rtcache_unref(rt, ro);
185 		rtcache_free(ro);
186 		percpu_putref(sc->gif_ro_percpu);
187 		m_freem(m);
188 		return ENETUNREACH;	/*XXX*/
189 	}
190 	rtcache_unref(rt, ro);
191 
192 	error = ip_output(m, NULL, ro, 0, NULL, NULL);
193 	percpu_putref(sc->gif_ro_percpu);
194 	return (error);
195 }
196 
197 void
198 in_gif_input(struct mbuf *m, int off, int proto)
199 {
200 	struct ifnet *gifp = NULL;
201 	const struct ip *ip;
202 	int af;
203 	u_int8_t otos;
204 
205 	ip = mtod(m, const struct ip *);
206 
207 	gifp = (struct ifnet *)encap_getarg(m);
208 
209 	if (gifp == NULL || (gifp->if_flags & (IFF_UP|IFF_RUNNING))
210 		!= (IFF_UP|IFF_RUNNING)) {
211 		m_freem(m);
212 		ip_statinc(IP_STAT_NOGIF);
213 		return;
214 	}
215 #ifndef GIF_ENCAPCHECK
216 	struct gif_softc *sc = (struct gif_softc *)gifp->if_softc;
217 	/* other CPU do delete_tunnel */
218 	if (sc->gif_psrc == NULL || sc->gif_pdst == NULL) {
219 		m_freem(m);
220 		ip_statinc(IP_STAT_NOGIF);
221 		return;
222 	}
223 
224 	struct ifnet *rcvif;
225 	struct psref psref;
226 	rcvif = m_get_rcvif_psref(m, &psref);
227 	if (!gif_validate4(ip, sc, rcvif)) {
228 		m_put_rcvif_psref(rcvif, &psref);
229 		m_freem(m);
230 		ip_statinc(IP_STAT_NOGIF);
231 		return;
232 	}
233 	m_put_rcvif_psref(rcvif, &psref);
234 #endif
235 	otos = ip->ip_tos;
236 	m_adj(m, off);
237 
238 	switch (proto) {
239 #ifdef INET
240 	case IPPROTO_IPV4:
241 	    {
242 		struct ip *xip;
243 		af = AF_INET;
244 		if (M_UNWRITABLE(m, sizeof(*xip))) {
245 			if ((m = m_pullup(m, sizeof(*xip))) == NULL)
246 				return;
247 		}
248 		xip = mtod(m, struct ip *);
249 		if (gifp->if_flags & IFF_LINK1)
250 			ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
251 		else
252 			ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos);
253 		break;
254 	    }
255 #endif
256 #ifdef INET6
257 	case IPPROTO_IPV6:
258 	    {
259 		struct ip6_hdr *ip6;
260 		u_int8_t itos;
261 		af = AF_INET6;
262 		if (M_UNWRITABLE(m, sizeof(*ip6))) {
263 			if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
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 		ip_statinc(IP_STAT_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(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
291 {
292 	struct sockaddr_in *src, *dst;
293 	struct in_ifaddr *ia4;
294 	int s;
295 
296 	src = satosin(sc->gif_psrc);
297 	dst = satosin(sc->gif_pdst);
298 
299 	/* check for address match */
300 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
301 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
302 		return 0;
303 
304 	/* martian filters on outer source - NOT done in ip_input! */
305 	if (IN_MULTICAST(ip->ip_src.s_addr))
306 		return 0;
307 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
308 	case 0: case 127: case 255:
309 		return 0;
310 	}
311 	/* reject packets with broadcast on source */
312 	s = pserialize_read_enter();
313 	IN_ADDRLIST_READER_FOREACH(ia4) {
314 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
315 			continue;
316 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
317 			pserialize_read_exit(s);
318 			return 0;
319 		}
320 	}
321 	pserialize_read_exit(s);
322 
323 	/* ingress filters on outer source */
324 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
325 		union {
326 			struct sockaddr sa;
327 			struct sockaddr_in sin;
328 		} u;
329 		struct rtentry *rt;
330 
331 		sockaddr_in_init(&u.sin, &ip->ip_src, 0);
332 		rt = rtalloc1(&u.sa, 0);
333 		if (rt == NULL || 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(u.sin.sin_addr.s_addr));
338 #endif
339 			if (rt != NULL)
340 				rt_unref(rt);
341 			return 0;
342 		}
343 		rt_unref(rt);
344 	}
345 
346 	return 32 * 2;
347 }
348 
349 #ifdef GIF_ENCAPCHECK
350 /*
351  * we know that we are in IFF_UP, outer address available, and outer family
352  * matched the physical addr family.  see gif_encapcheck().
353  */
354 int
355 gif_encapcheck4(struct mbuf *m, int off, int proto, void *arg)
356 {
357 	struct ip ip;
358 	struct gif_softc *sc;
359 	struct ifnet *ifp = NULL;
360 	int r;
361 	struct psref psref;
362 
363 	/* sanity check done in caller */
364 	sc = arg;
365 
366 	m_copydata(m, 0, sizeof(ip), &ip);
367 	if ((m->m_flags & M_PKTHDR) != 0)
368 		ifp = m_get_rcvif_psref(m, &psref);
369 
370 	r = gif_validate4(&ip, sc, ifp);
371 
372 	m_put_rcvif_psref(ifp, &psref);
373 	return r;
374 }
375 #endif
376 
377 int
378 in_gif_attach(struct gif_softc *sc)
379 {
380 #ifndef GIF_ENCAPCHECK
381 	struct sockaddr_in mask4;
382 
383 	memset(&mask4, 0, sizeof(mask4));
384 	mask4.sin_len = sizeof(struct sockaddr_in);
385 	mask4.sin_addr.s_addr = ~0;
386 
387 	if (!sc->gif_psrc || !sc->gif_pdst)
388 		return EINVAL;
389 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
390 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
391 	    &in_gif_encapsw, sc);
392 #else
393 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
394 	    &in_gif_encapsw, sc);
395 #endif
396 	if (sc->encap_cookie4 == NULL)
397 		return EEXIST;
398 	return 0;
399 }
400 
401 int
402 in_gif_detach(struct gif_softc *sc)
403 {
404 	int error;
405 
406 	error = in_gif_pause(sc);
407 
408 	percpu_foreach(sc->gif_ro_percpu, gif_rtcache_free_pc, NULL);
409 
410 	return error;
411 }
412 
413 int
414 in_gif_pause(struct gif_softc *sc)
415 {
416 	int error;
417 
418 	error = encap_detach(sc->encap_cookie4);
419 	if (error == 0)
420 		sc->encap_cookie4 = NULL;
421 
422 	return error;
423 }
424