xref: /netbsd-src/sys/netinet/in_gif.c (revision caa46aef53e2498cff6070c42d8e8ae8fd7f6a51) 
1 /*	$NetBSD: in_gif.c,v 1.67 2015/12/25 06:47:56 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 1.67 2015/12/25 06:47:56 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/protosw.h>
49 #include <sys/kernel.h>
50 
51 #include <net/if.h>
52 #include <net/route.h>
53 
54 #include <netinet/in.h>
55 #include <netinet/in_systm.h>
56 #include <netinet/ip.h>
57 #include <netinet/ip_var.h>
58 #include <netinet/in_gif.h>
59 #include <netinet/in_var.h>
60 #include <netinet/ip_encap.h>
61 #include <netinet/ip_ecn.h>
62 
63 #ifdef INET6
64 #include <netinet/ip6.h>
65 #endif
66 
67 #include <net/if_gif.h>
68 
69 #include "gif.h"
70 
71 #include <net/net_osdep.h>
72 
73 static int gif_validate4(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 	.pr_type	= SOCK_RAW,
84 	.pr_domain	= &inetdomain,
85 	.pr_protocol	= 0 /* IPPROTO_IPV[46] */,
86 	.pr_flags	= PR_ATOMIC|PR_ADDR,
87 	.pr_input	= in_gif_input,
88 	.pr_output	= rip_output,
89 	.pr_ctlinput	= NULL,
90 	.pr_ctloutput	= rip_ctloutput,
91 	.pr_usrreqs	= &rip_usrreqs,
92 };
93 
94 int
95 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
96 {
97 	struct rtentry *rt;
98 	struct gif_softc *sc = ifp->if_softc;
99 	struct sockaddr_in *sin_src = satosin(sc->gif_psrc);
100 	struct sockaddr_in *sin_dst = satosin(sc->gif_pdst);
101 	struct ip iphdr;	/* capsule IP header, host byte ordered */
102 	int proto, error;
103 	u_int8_t tos;
104 	union {
105 		struct sockaddr		dst;
106 		struct sockaddr_in	dst4;
107 	} u;
108 
109 	if (sin_src == NULL || sin_dst == NULL ||
110 	    sin_src->sin_family != AF_INET ||
111 	    sin_dst->sin_family != AF_INET) {
112 		m_freem(m);
113 		return EAFNOSUPPORT;
114 	}
115 
116 	switch (family) {
117 #ifdef INET
118 	case AF_INET:
119 	    {
120 		const struct ip *ip;
121 
122 		proto = IPPROTO_IPV4;
123 		if (m->m_len < sizeof(*ip)) {
124 			m = m_pullup(m, sizeof(*ip));
125 			if (m == NULL)
126 				return ENOBUFS;
127 		}
128 		ip = mtod(m, const struct ip *);
129 		tos = ip->ip_tos;
130 		break;
131 	    }
132 #endif /* INET */
133 #ifdef INET6
134 	case AF_INET6:
135 	    {
136 		const struct ip6_hdr *ip6;
137 		proto = IPPROTO_IPV6;
138 		if (m->m_len < sizeof(*ip6)) {
139 			m = m_pullup(m, sizeof(*ip6));
140 			if (m == NULL)
141 				return ENOBUFS;
142 		}
143 		ip6 = mtod(m, const struct ip6_hdr *);
144 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
145 		break;
146 	    }
147 #endif /* INET6 */
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 	struct gif_softc *sc = (struct gif_softc *)gifp->if_softc;
227 	/* other CPU do delete_tunnel */
228 	if (sc->gif_psrc == NULL || sc->gif_pdst == NULL) {
229 		m_freem(m);
230 		ip_statinc(IP_STAT_NOGIF);
231 		return;
232 	}
233 
234 	if (!gif_validate4(ip, sc, m->m_pkthdr.rcvif)) {
235 		m_freem(m);
236 		ip_statinc(IP_STAT_NOGIF);
237 		return;
238 	}
239 #endif
240 	otos = ip->ip_tos;
241 	m_adj(m, off);
242 
243 	switch (proto) {
244 #ifdef INET
245 	case IPPROTO_IPV4:
246 	    {
247 		struct ip *xip;
248 		af = AF_INET;
249 		if (M_UNWRITABLE(m, sizeof(*xip))) {
250 			if ((m = m_pullup(m, sizeof(*xip))) == NULL)
251 				return;
252 		}
253 		xip = mtod(m, struct ip *);
254 		if (gifp->if_flags & IFF_LINK1)
255 			ip_ecn_egress(ECN_ALLOWED, &otos, &xip->ip_tos);
256 		else
257 			ip_ecn_egress(ECN_NOCARE, &otos, &xip->ip_tos);
258 		break;
259 	    }
260 #endif
261 #ifdef INET6
262 	case IPPROTO_IPV6:
263 	    {
264 		struct ip6_hdr *ip6;
265 		u_int8_t itos;
266 		af = AF_INET6;
267 		if (M_UNWRITABLE(m, sizeof(*ip6))) {
268 			if ((m = m_pullup(m, sizeof(*ip6))) == NULL)
269 				return;
270 		}
271 		ip6 = mtod(m, struct ip6_hdr *);
272 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
273 		if (gifp->if_flags & IFF_LINK1)
274 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
275 		else
276 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
277 		ip6->ip6_flow &= ~htonl(0xff << 20);
278 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
279 		break;
280 	    }
281 #endif /* INET6 */
282 	default:
283 		ip_statinc(IP_STAT_NOGIF);
284 		m_freem(m);
285 		return;
286 	}
287 	gif_input(m, af, gifp);
288 	return;
289 }
290 
291 /*
292  * validate outer address.
293  */
294 static int
295 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
296 {
297 	struct sockaddr_in *src, *dst;
298 	struct in_ifaddr *ia4;
299 
300 	src = satosin(sc->gif_psrc);
301 	dst = satosin(sc->gif_pdst);
302 
303 	/* check for address match */
304 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
305 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
306 		return 0;
307 
308 	/* martian filters on outer source - NOT done in ip_input! */
309 	if (IN_MULTICAST(ip->ip_src.s_addr))
310 		return 0;
311 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
312 	case 0: case 127: case 255:
313 		return 0;
314 	}
315 	/* reject packets with broadcast on source */
316 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list) {
317 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
318 			continue;
319 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
320 			return 0;
321 	}
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 				rtfree(rt);
341 			return 0;
342 		}
343 		rtfree(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;
360 
361 	/* sanity check done in caller */
362 	sc = arg;
363 
364 	m_copydata(m, 0, sizeof(ip), &ip);
365 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
366 
367 	return gif_validate4(&ip, sc, ifp);
368 }
369 #endif
370 
371 int
372 in_gif_attach(struct gif_softc *sc)
373 {
374 #ifndef GIF_ENCAPCHECK
375 	struct sockaddr_in mask4;
376 
377 	memset(&mask4, 0, sizeof(mask4));
378 	mask4.sin_len = sizeof(struct sockaddr_in);
379 	mask4.sin_addr.s_addr = ~0;
380 
381 	if (!sc->gif_psrc || !sc->gif_pdst)
382 		return EINVAL;
383 	sc->encap_cookie4 = encap_attach(AF_INET, -1, sc->gif_psrc,
384 	    (struct sockaddr *)&mask4, sc->gif_pdst, (struct sockaddr *)&mask4,
385 	    (const struct protosw *)&in_gif_protosw, sc);
386 #else
387 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
388 	    &in_gif_protosw, sc);
389 #endif
390 	if (sc->encap_cookie4 == NULL)
391 		return EEXIST;
392 	return 0;
393 }
394 
395 int
396 in_gif_detach(struct gif_softc *sc)
397 {
398 	int error;
399 
400 	error = encap_detach(sc->encap_cookie4);
401 	if (error == 0)
402 		sc->encap_cookie4 = NULL;
403 
404 	rtcache_free(&sc->gif_ro);
405 
406 	return error;
407 }
408