xref: /freebsd/sys/netinet/in_gif.c (revision d876124d6ae9d56da5b4ff4c6015efd1d0c9222a) 
1 /*	$KAME: in_gif.c,v 1.54 2001/05/14 14:02:16 itojun Exp $	*/
2 
3 /*-
4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the project nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_mrouting.h"
36 #include "opt_inet.h"
37 #include "opt_inet6.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/kernel.h>
46 #include <sys/sysctl.h>
47 #include <sys/protosw.h>
48 
49 #include <sys/malloc.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 #ifdef MROUTING
68 #include <netinet/ip_mroute.h>
69 #endif /* MROUTING */
70 
71 #include <net/if_gif.h>
72 
73 static int gif_validate4(const struct ip *, struct gif_softc *,
74 	struct ifnet *);
75 
76 extern  struct domain inetdomain;
77 struct protosw in_gif_protosw = {
78 	.pr_type =		SOCK_RAW,
79 	.pr_domain =		&inetdomain,
80 	.pr_protocol =		0/* IPPROTO_IPV[46] */,
81 	.pr_flags =		PR_ATOMIC|PR_ADDR,
82 	.pr_input =		in_gif_input,
83 	.pr_output =		(pr_output_t*)rip_output,
84 	.pr_ctloutput =		rip_ctloutput,
85 	.pr_usrreqs =		&rip_usrreqs
86 };
87 
88 static int ip_gif_ttl = GIF_TTL;
89 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
90 	&ip_gif_ttl,	0, "");
91 
92 int
93 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
94 {
95 	struct gif_softc *sc = ifp->if_softc;
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 	struct etherip_header eiphdr;
101 	int proto, error;
102 	u_int8_t tos;
103 
104 	GIF_LOCK_ASSERT(sc);
105 
106 	if (sin_src == NULL || sin_dst == NULL ||
107 	    sin_src->sin_family != AF_INET ||
108 	    sin_dst->sin_family != AF_INET) {
109 		m_freem(m);
110 		return EAFNOSUPPORT;
111 	}
112 
113 	switch (family) {
114 #ifdef INET
115 	case AF_INET:
116 	    {
117 		struct ip *ip;
118 
119 		proto = IPPROTO_IPV4;
120 		if (m->m_len < sizeof(*ip)) {
121 			m = m_pullup(m, sizeof(*ip));
122 			if (!m)
123 				return ENOBUFS;
124 		}
125 		ip = mtod(m, struct ip *);
126 		tos = ip->ip_tos;
127 		break;
128 	    }
129 #endif /* INET */
130 #ifdef INET6
131 	case AF_INET6:
132 	    {
133 		struct ip6_hdr *ip6;
134 		proto = IPPROTO_IPV6;
135 		if (m->m_len < sizeof(*ip6)) {
136 			m = m_pullup(m, sizeof(*ip6));
137 			if (!m)
138 				return ENOBUFS;
139 		}
140 		ip6 = mtod(m, struct ip6_hdr *);
141 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
142 		break;
143 	    }
144 #endif /* INET6 */
145 	case AF_LINK:
146  		proto = IPPROTO_ETHERIP;
147  		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
148  		eiphdr.eip_pad = 0;
149  		/* prepend Ethernet-in-IP header */
150  		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
151  		if (m && m->m_len < sizeof(struct etherip_header))
152  			m = m_pullup(m, sizeof(struct etherip_header));
153  		if (m == NULL)
154  			return ENOBUFS;
155  		bcopy(&eiphdr, mtod(m, struct etherip_header *),
156 		    sizeof(struct etherip_header));
157 		break;
158 
159 	default:
160 #ifdef DEBUG
161 		printf("in_gif_output: warning: unknown family %d passed\n",
162 			family);
163 #endif
164 		m_freem(m);
165 		return EAFNOSUPPORT;
166 	}
167 
168 	bzero(&iphdr, sizeof(iphdr));
169 	iphdr.ip_src = sin_src->sin_addr;
170 	/* bidirectional configured tunnel mode */
171 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
172 		iphdr.ip_dst = sin_dst->sin_addr;
173 	else {
174 		m_freem(m);
175 		return ENETUNREACH;
176 	}
177 	iphdr.ip_p = proto;
178 	/* version will be set in ip_output() */
179 	iphdr.ip_ttl = ip_gif_ttl;
180 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
181 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
182 		       &iphdr.ip_tos, &tos);
183 
184 	/* prepend new IP header */
185 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
186 	if (m && m->m_len < sizeof(struct ip))
187 		m = m_pullup(m, sizeof(struct ip));
188 	if (m == NULL) {
189 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
190 		return ENOBUFS;
191 	}
192 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
193 
194 	if (dst->sin_family != sin_dst->sin_family ||
195 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
196 		/* cache route doesn't match */
197 		bzero(dst, sizeof(*dst));
198 		dst->sin_family = sin_dst->sin_family;
199 		dst->sin_len = sizeof(struct sockaddr_in);
200 		dst->sin_addr = sin_dst->sin_addr;
201 		if (sc->gif_ro.ro_rt) {
202 			RTFREE(sc->gif_ro.ro_rt);
203 			sc->gif_ro.ro_rt = NULL;
204 		}
205 #if 0
206 		GIF2IFP(sc)->if_mtu = GIF_MTU;
207 #endif
208 	}
209 
210 	if (sc->gif_ro.ro_rt == NULL) {
211 		rtalloc_ign(&sc->gif_ro, 0);
212 		if (sc->gif_ro.ro_rt == NULL) {
213 			m_freem(m);
214 			return ENETUNREACH;
215 		}
216 
217 		/* if it constitutes infinite encapsulation, punt. */
218 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
219 			m_freem(m);
220 			return ENETUNREACH;	/* XXX */
221 		}
222 #if 0
223 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
224 			- sizeof(struct ip);
225 #endif
226 	}
227 
228 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
229 
230 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
231 	    sc->gif_ro.ro_rt != NULL) {
232 		RTFREE(sc->gif_ro.ro_rt);
233 		sc->gif_ro.ro_rt = NULL;
234 	}
235 
236 	return (error);
237 }
238 
239 void
240 in_gif_input(struct mbuf *m, int off)
241 {
242 	struct ifnet *gifp = NULL;
243 	struct gif_softc *sc;
244 	struct ip *ip;
245 	int af;
246 	u_int8_t otos;
247 	int proto;
248 
249 	ip = mtod(m, struct ip *);
250 	proto = ip->ip_p;
251 
252 	sc = (struct gif_softc *)encap_getarg(m);
253 	if (sc == NULL) {
254 		m_freem(m);
255 		ipstat.ips_nogif++;
256 		return;
257 	}
258 
259 	gifp = GIF2IFP(sc);
260 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
261 		m_freem(m);
262 		ipstat.ips_nogif++;
263 		return;
264 	}
265 
266 	otos = ip->ip_tos;
267 	m_adj(m, off);
268 
269 	switch (proto) {
270 #ifdef INET
271 	case IPPROTO_IPV4:
272 	    {
273 		struct ip *ip;
274 		af = AF_INET;
275 		if (m->m_len < sizeof(*ip)) {
276 			m = m_pullup(m, sizeof(*ip));
277 			if (!m)
278 				return;
279 		}
280 		ip = mtod(m, struct ip *);
281 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
282 				  ECN_ALLOWED : ECN_NOCARE,
283 				  &otos, &ip->ip_tos) == 0) {
284 			m_freem(m);
285 			return;
286 		}
287 		break;
288 	    }
289 #endif
290 #ifdef INET6
291 	case IPPROTO_IPV6:
292 	    {
293 		struct ip6_hdr *ip6;
294 		u_int8_t itos, oitos;
295 
296 		af = AF_INET6;
297 		if (m->m_len < sizeof(*ip6)) {
298 			m = m_pullup(m, sizeof(*ip6));
299 			if (!m)
300 				return;
301 		}
302 		ip6 = mtod(m, struct ip6_hdr *);
303 		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
304 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
305 				  ECN_ALLOWED : ECN_NOCARE,
306 				  &otos, &itos) == 0) {
307 			m_freem(m);
308 			return;
309 		}
310 		if (itos != oitos) {
311 			ip6->ip6_flow &= ~htonl(0xff << 20);
312 			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
313 		}
314 		break;
315 	    }
316 #endif /* INET6 */
317  	case IPPROTO_ETHERIP:
318  		af = AF_LINK;
319  		break;
320 
321 	default:
322 		ipstat.ips_nogif++;
323 		m_freem(m);
324 		return;
325 	}
326 	gif_input(m, af, gifp);
327 	return;
328 }
329 
330 /*
331  * validate outer address.
332  */
333 static int
334 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
335 {
336 	struct sockaddr_in *src, *dst;
337 	struct in_ifaddr *ia4;
338 
339 	src = (struct sockaddr_in *)sc->gif_psrc;
340 	dst = (struct sockaddr_in *)sc->gif_pdst;
341 
342 	/* check for address match */
343 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
344 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
345 		return 0;
346 
347 	/* martian filters on outer source - NOT done in ip_input! */
348 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
349 		return 0;
350 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
351 	case 0: case 127: case 255:
352 		return 0;
353 	}
354 	/* reject packets with broadcast on source */
355 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
356 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
357 			continue;
358 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
359 			return 0;
360 	}
361 
362 	/* ingress filters on outer source */
363 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
364 		struct sockaddr_in sin;
365 		struct rtentry *rt;
366 
367 		bzero(&sin, sizeof(sin));
368 		sin.sin_family = AF_INET;
369 		sin.sin_len = sizeof(struct sockaddr_in);
370 		sin.sin_addr = ip->ip_src;
371 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
372 		if (!rt || rt->rt_ifp != ifp) {
373 #if 0
374 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
375 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
376 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
377 #endif
378 			if (rt)
379 				RTFREE_LOCKED(rt);
380 			return 0;
381 		}
382 		RTFREE_LOCKED(rt);
383 	}
384 
385 	return 32 * 2;
386 }
387 
388 /*
389  * we know that we are in IFF_UP, outer address available, and outer family
390  * matched the physical addr family.  see gif_encapcheck().
391  */
392 int
393 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
394 {
395 	struct ip ip;
396 	struct gif_softc *sc;
397 	struct ifnet *ifp;
398 
399 	/* sanity check done in caller */
400 	sc = (struct gif_softc *)arg;
401 
402 	/* LINTED const cast */
403 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
404 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
405 
406 	return gif_validate4(&ip, sc, ifp);
407 }
408 
409 int
410 in_gif_attach(struct gif_softc *sc)
411 {
412 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
413 	    &in_gif_protosw, sc);
414 	if (sc->encap_cookie4 == NULL)
415 		return EEXIST;
416 	return 0;
417 }
418 
419 int
420 in_gif_detach(struct gif_softc *sc)
421 {
422 	int error;
423 
424 	error = encap_detach(sc->encap_cookie4);
425 	if (error == 0)
426 		sc->encap_cookie4 = NULL;
427 	return error;
428 }
429