xref: /dragonfly/sys/netinet/in_gif.c (revision 984263bc) 
1 /*	$FreeBSD: src/sys/netinet/in_gif.c,v 1.5.2.11 2003/01/23 21:06:45 sam Exp $	*/
2 /*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 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 "opt_inet.h"
34 #include "opt_inet6.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/socket.h>
39 #include <sys/sockio.h>
40 #include <sys/mbuf.h>
41 #include <sys/errno.h>
42 #include <sys/kernel.h>
43 #include <sys/sysctl.h>
44 #include <sys/protosw.h>
45 
46 #include <sys/malloc.h>
47 
48 #include <net/if.h>
49 #include <net/route.h>
50 
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/ip.h>
54 #include <netinet/ip_var.h>
55 #include <netinet/in_gif.h>
56 #include <netinet/in_var.h>
57 #include <netinet/ip_encap.h>
58 #include <netinet/ip_ecn.h>
59 
60 #ifdef INET6
61 #include <netinet/ip6.h>
62 #endif
63 
64 #include <net/if_gif.h>
65 
66 #include <net/net_osdep.h>
67 
68 static int gif_validate4 __P((const struct ip *, struct gif_softc *,
69 	struct ifnet *));
70 
71 extern  struct domain inetdomain;
72 struct protosw in_gif_protosw =
73 { SOCK_RAW,	&inetdomain,	0/*IPPROTO_IPV[46]*/,	PR_ATOMIC|PR_ADDR,
74   in_gif_input,	rip_output,	0,		rip_ctloutput,
75   0,
76   0,		0,		0,		0,
77   &rip_usrreqs
78 };
79 
80 int ip_gif_ttl = GIF_TTL;
81 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
82 	&ip_gif_ttl,	0, "");
83 
84 int
85 in_gif_output(ifp, family, m)
86 	struct ifnet	*ifp;
87 	int		family;
88 	struct mbuf	*m;
89 {
90 	struct gif_softc *sc = (struct gif_softc*)ifp;
91 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
92 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
93 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
94 	struct ip iphdr;	/* capsule IP header, host byte ordered */
95 	int proto, error;
96 	u_int8_t tos;
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 		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)
115 				return ENOBUFS;
116 		}
117 		ip = mtod(m, struct ip *);
118 		tos = ip->ip_tos;
119 		break;
120 	    }
121 #endif /* INET */
122 #ifdef INET6
123 	case AF_INET6:
124 	    {
125 		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)
130 				return ENOBUFS;
131 		}
132 		ip6 = mtod(m, 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 	bzero(&iphdr, 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 = 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 	if (m && m->m_len < sizeof(struct ip))
167 		m = m_pullup(m, sizeof(struct ip));
168 	if (m == NULL) {
169 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
170 		return ENOBUFS;
171 	}
172 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
173 
174 	if (dst->sin_family != sin_dst->sin_family ||
175 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
176 		/* cache route doesn't match */
177 		dst->sin_family = sin_dst->sin_family;
178 		dst->sin_len = sizeof(struct sockaddr_in);
179 		dst->sin_addr = sin_dst->sin_addr;
180 		if (sc->gif_ro.ro_rt) {
181 			RTFREE(sc->gif_ro.ro_rt);
182 			sc->gif_ro.ro_rt = NULL;
183 		}
184 #if 0
185 		sc->gif_if.if_mtu = GIF_MTU;
186 #endif
187 	}
188 
189 	if (sc->gif_ro.ro_rt == NULL) {
190 		rtalloc(&sc->gif_ro);
191 		if (sc->gif_ro.ro_rt == NULL) {
192 			m_freem(m);
193 			return ENETUNREACH;
194 		}
195 
196 		/* if it constitutes infinite encapsulation, punt. */
197 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
198 			m_freem(m);
199 			return ENETUNREACH;	/* XXX */
200 		}
201 #if 0
202 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
203 			- sizeof(struct ip);
204 #endif
205 	}
206 
207 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
208 	return(error);
209 }
210 
211 void
212 in_gif_input(m, off, proto)
213 	struct mbuf *m;
214 	int off;
215 	int proto;
216 {
217 	struct ifnet *gifp = NULL;
218 	struct ip *ip;
219 	int af;
220 	u_int8_t otos;
221 
222 	ip = mtod(m, struct ip *);
223 
224 	gifp = (struct ifnet *)encap_getarg(m);
225 
226 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
227 		m_freem(m);
228 		ipstat.ips_nogif++;
229 		return;
230 	}
231 
232 	otos = ip->ip_tos;
233 	m_adj(m, off);
234 
235 	switch (proto) {
236 #ifdef INET
237 	case IPPROTO_IPV4:
238 	    {
239 		struct ip *ip;
240 		af = AF_INET;
241 		if (m->m_len < sizeof(*ip)) {
242 			m = m_pullup(m, sizeof(*ip));
243 			if (!m)
244 				return;
245 		}
246 		ip = mtod(m, struct ip *);
247 		if (gifp->if_flags & IFF_LINK1)
248 			ip_ecn_egress(ECN_ALLOWED, &otos, &ip->ip_tos);
249 		else
250 			ip_ecn_egress(ECN_NOCARE, &otos, &ip->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->m_len < sizeof(*ip6)) {
261 			m = m_pullup(m, sizeof(*ip6));
262 			if (!m)
263 				return;
264 		}
265 		ip6 = mtod(m, struct ip6_hdr *);
266 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
267 		if (gifp->if_flags & IFF_LINK1)
268 			ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
269 		else
270 			ip_ecn_egress(ECN_NOCARE, &otos, &itos);
271 		ip6->ip6_flow &= ~htonl(0xff << 20);
272 		ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
273 		break;
274 	    }
275 #endif /* INET6 */
276 	default:
277 		ipstat.ips_nogif++;
278 		m_freem(m);
279 		return;
280 	}
281 	gif_input(m, af, gifp);
282 	return;
283 }
284 
285 /*
286  * validate outer address.
287  */
288 static int
289 gif_validate4(ip, sc, ifp)
290 	const struct ip *ip;
291 	struct gif_softc *sc;
292 	struct ifnet *ifp;
293 {
294 	struct sockaddr_in *src, *dst;
295 	struct in_ifaddr *ia4;
296 
297 	src = (struct sockaddr_in *)sc->gif_psrc;
298 	dst = (struct sockaddr_in *)sc->gif_pdst;
299 
300 	/* check for address match */
301 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
302 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
303 		return 0;
304 
305 	/* martian filters on outer source - NOT done in ip_input! */
306 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
307 		return 0;
308 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
309 	case 0: case 127: case 255:
310 		return 0;
311 	}
312 	/* reject packets with broadcast on source */
313 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead); ia4;
314 	     ia4 = TAILQ_NEXT(ia4, ia_link))
315 	{
316 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
317 			continue;
318 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
319 			return 0;
320 	}
321 
322 	/* ingress filters on outer source */
323 	if ((sc->gif_if.if_flags & IFF_LINK2) == 0 && ifp) {
324 		struct sockaddr_in sin;
325 		struct rtentry *rt;
326 
327 		bzero(&sin, sizeof(sin));
328 		sin.sin_family = AF_INET;
329 		sin.sin_len = sizeof(struct sockaddr_in);
330 		sin.sin_addr = ip->ip_src;
331 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
332 		if (!rt || rt->rt_ifp != ifp) {
333 #if 0
334 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
335 			    "due to ingress filter\n", if_name(&sc->gif_if),
336 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
337 #endif
338 			if (rt)
339 				rtfree(rt);
340 			return 0;
341 		}
342 		rtfree(rt);
343 	}
344 
345 	return 32 * 2;
346 }
347 
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(m, off, proto, arg)
354 	const struct mbuf *m;
355 	int off;
356 	int proto;
357 	void *arg;
358 {
359 	struct ip ip;
360 	struct gif_softc *sc;
361 	struct ifnet *ifp;
362 
363 	/* sanity check done in caller */
364 	sc = (struct gif_softc *)arg;
365 
366 	/* LINTED const cast */
367 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
368 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
369 
370 	return gif_validate4(&ip, sc, ifp);
371 }
372 
373 int
374 in_gif_attach(sc)
375 	struct gif_softc *sc;
376 {
377 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
378 	    &in_gif_protosw, sc);
379 	if (sc->encap_cookie4 == NULL)
380 		return EEXIST;
381 	return 0;
382 }
383 
384 int
385 in_gif_detach(sc)
386 	struct gif_softc *sc;
387 {
388 	int error;
389 
390 	error = encap_detach(sc->encap_cookie4);
391 	if (error == 0)
392 		sc->encap_cookie4 = NULL;
393 	return error;
394 }
395