xref: /freebsd/sys/netinet/in_gif.c (revision 94942af266ac119ede0ca836f9aa5a5ac0582938) 
1 /*	$FreeBSD$	*/
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_mrouting.h"
34 #include "opt_inet.h"
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/socket.h>
40 #include <sys/sockio.h>
41 #include <sys/mbuf.h>
42 #include <sys/errno.h>
43 #include <sys/kernel.h>
44 #include <sys/sysctl.h>
45 #include <sys/protosw.h>
46 
47 #include <sys/malloc.h>
48 
49 #include <net/if.h>
50 #include <net/route.h>
51 
52 #include <netinet/in.h>
53 #include <netinet/in_systm.h>
54 #include <netinet/ip.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/in_gif.h>
57 #include <netinet/in_var.h>
58 #include <netinet/ip_encap.h>
59 #include <netinet/ip_ecn.h>
60 
61 #ifdef INET6
62 #include <netinet/ip6.h>
63 #endif
64 
65 #ifdef MROUTING
66 #include <netinet/ip_mroute.h>
67 #endif /* MROUTING */
68 
69 #include <net/if_gif.h>
70 
71 static int gif_validate4(const struct ip *, struct gif_softc *,
72 	struct ifnet *);
73 
74 extern  struct domain inetdomain;
75 struct protosw in_gif_protosw = {
76 	.pr_type =		SOCK_RAW,
77 	.pr_domain =		&inetdomain,
78 	.pr_protocol =		0/* IPPROTO_IPV[46] */,
79 	.pr_flags =		PR_ATOMIC|PR_ADDR,
80 	.pr_input =		in_gif_input,
81 	.pr_output =		(pr_output_t*)rip_output,
82 	.pr_ctloutput =		rip_ctloutput,
83 	.pr_usrreqs =		&rip_usrreqs
84 };
85 
86 static int ip_gif_ttl = GIF_TTL;
87 SYSCTL_INT(_net_inet_ip, IPCTL_GIF_TTL, gifttl, CTLFLAG_RW,
88 	&ip_gif_ttl,	0, "");
89 
90 int
91 in_gif_output(struct ifnet *ifp, int family, struct mbuf *m)
92 {
93 	struct gif_softc *sc = ifp->if_softc;
94 	struct sockaddr_in *dst = (struct sockaddr_in *)&sc->gif_ro.ro_dst;
95 	struct sockaddr_in *sin_src = (struct sockaddr_in *)sc->gif_psrc;
96 	struct sockaddr_in *sin_dst = (struct sockaddr_in *)sc->gif_pdst;
97 	struct ip iphdr;	/* capsule IP header, host byte ordered */
98 	struct etherip_header eiphdr;
99 	int proto, error;
100 	u_int8_t tos;
101 
102 	GIF_LOCK_ASSERT(sc);
103 
104 	if (sin_src == NULL || sin_dst == NULL ||
105 	    sin_src->sin_family != AF_INET ||
106 	    sin_dst->sin_family != AF_INET) {
107 		m_freem(m);
108 		return EAFNOSUPPORT;
109 	}
110 
111 	switch (family) {
112 #ifdef INET
113 	case AF_INET:
114 	    {
115 		struct ip *ip;
116 
117 		proto = IPPROTO_IPV4;
118 		if (m->m_len < sizeof(*ip)) {
119 			m = m_pullup(m, sizeof(*ip));
120 			if (!m)
121 				return ENOBUFS;
122 		}
123 		ip = mtod(m, struct ip *);
124 		tos = ip->ip_tos;
125 		break;
126 	    }
127 #endif /* INET */
128 #ifdef INET6
129 	case AF_INET6:
130 	    {
131 		struct ip6_hdr *ip6;
132 		proto = IPPROTO_IPV6;
133 		if (m->m_len < sizeof(*ip6)) {
134 			m = m_pullup(m, sizeof(*ip6));
135 			if (!m)
136 				return ENOBUFS;
137 		}
138 		ip6 = mtod(m, struct ip6_hdr *);
139 		tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
140 		break;
141 	    }
142 #endif /* INET6 */
143 	case AF_LINK:
144  		proto = IPPROTO_ETHERIP;
145  		eiphdr.eip_ver = ETHERIP_VERSION & ETHERIP_VER_VERS_MASK;
146  		eiphdr.eip_pad = 0;
147  		/* prepend Ethernet-in-IP header */
148  		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
149  		if (m && m->m_len < sizeof(struct etherip_header))
150  			m = m_pullup(m, sizeof(struct etherip_header));
151  		if (m == NULL)
152  			return ENOBUFS;
153  		bcopy(&eiphdr, mtod(m, struct etherip_header *),
154 		    sizeof(struct etherip_header));
155 		break;
156 
157 	default:
158 #ifdef DEBUG
159 		printf("in_gif_output: warning: unknown family %d passed\n",
160 			family);
161 #endif
162 		m_freem(m);
163 		return EAFNOSUPPORT;
164 	}
165 
166 	bzero(&iphdr, sizeof(iphdr));
167 	iphdr.ip_src = sin_src->sin_addr;
168 	/* bidirectional configured tunnel mode */
169 	if (sin_dst->sin_addr.s_addr != INADDR_ANY)
170 		iphdr.ip_dst = sin_dst->sin_addr;
171 	else {
172 		m_freem(m);
173 		return ENETUNREACH;
174 	}
175 	iphdr.ip_p = proto;
176 	/* version will be set in ip_output() */
177 	iphdr.ip_ttl = ip_gif_ttl;
178 	iphdr.ip_len = m->m_pkthdr.len + sizeof(struct ip);
179 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
180 		       &iphdr.ip_tos, &tos);
181 
182 	/* prepend new IP header */
183 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
184 	if (m && m->m_len < sizeof(struct ip))
185 		m = m_pullup(m, sizeof(struct ip));
186 	if (m == NULL) {
187 		printf("ENOBUFS in in_gif_output %d\n", __LINE__);
188 		return ENOBUFS;
189 	}
190 	bcopy(&iphdr, mtod(m, struct ip *), sizeof(struct ip));
191 
192 	if (dst->sin_family != sin_dst->sin_family ||
193 	    dst->sin_addr.s_addr != sin_dst->sin_addr.s_addr) {
194 		/* cache route doesn't match */
195 		bzero(dst, sizeof(*dst));
196 		dst->sin_family = sin_dst->sin_family;
197 		dst->sin_len = sizeof(struct sockaddr_in);
198 		dst->sin_addr = sin_dst->sin_addr;
199 		if (sc->gif_ro.ro_rt) {
200 			RTFREE(sc->gif_ro.ro_rt);
201 			sc->gif_ro.ro_rt = NULL;
202 		}
203 #if 0
204 		GIF2IFP(sc)->if_mtu = GIF_MTU;
205 #endif
206 	}
207 
208 	if (sc->gif_ro.ro_rt == NULL) {
209 		rtalloc_ign(&sc->gif_ro, 0);
210 		if (sc->gif_ro.ro_rt == NULL) {
211 			m_freem(m);
212 			return ENETUNREACH;
213 		}
214 
215 		/* if it constitutes infinite encapsulation, punt. */
216 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
217 			m_freem(m);
218 			return ENETUNREACH;	/* XXX */
219 		}
220 #if 0
221 		ifp->if_mtu = sc->gif_ro.ro_rt->rt_ifp->if_mtu
222 			- sizeof(struct ip);
223 #endif
224 	}
225 
226 	error = ip_output(m, NULL, &sc->gif_ro, 0, NULL, NULL);
227 
228 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
229 	    sc->gif_ro.ro_rt != NULL) {
230 		RTFREE(sc->gif_ro.ro_rt);
231 		sc->gif_ro.ro_rt = NULL;
232 	}
233 
234 	return (error);
235 }
236 
237 void
238 in_gif_input(struct mbuf *m, int off)
239 {
240 	struct ifnet *gifp = NULL;
241 	struct gif_softc *sc;
242 	struct ip *ip;
243 	int af;
244 	u_int8_t otos;
245 	int proto;
246 
247 	ip = mtod(m, struct ip *);
248 	proto = ip->ip_p;
249 
250 	sc = (struct gif_softc *)encap_getarg(m);
251 	if (sc == NULL) {
252 		m_freem(m);
253 		ipstat.ips_nogif++;
254 		return;
255 	}
256 
257 	gifp = GIF2IFP(sc);
258 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
259 		m_freem(m);
260 		ipstat.ips_nogif++;
261 		return;
262 	}
263 
264 	otos = ip->ip_tos;
265 	m_adj(m, off);
266 
267 	switch (proto) {
268 #ifdef INET
269 	case IPPROTO_IPV4:
270 	    {
271 		struct ip *ip;
272 		af = AF_INET;
273 		if (m->m_len < sizeof(*ip)) {
274 			m = m_pullup(m, sizeof(*ip));
275 			if (!m)
276 				return;
277 		}
278 		ip = mtod(m, struct ip *);
279 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
280 				  ECN_ALLOWED : ECN_NOCARE,
281 				  &otos, &ip->ip_tos) == 0) {
282 			m_freem(m);
283 			return;
284 		}
285 		break;
286 	    }
287 #endif
288 #ifdef INET6
289 	case IPPROTO_IPV6:
290 	    {
291 		struct ip6_hdr *ip6;
292 		u_int8_t itos, oitos;
293 
294 		af = AF_INET6;
295 		if (m->m_len < sizeof(*ip6)) {
296 			m = m_pullup(m, sizeof(*ip6));
297 			if (!m)
298 				return;
299 		}
300 		ip6 = mtod(m, struct ip6_hdr *);
301 		itos = oitos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
302 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
303 				  ECN_ALLOWED : ECN_NOCARE,
304 				  &otos, &itos) == 0) {
305 			m_freem(m);
306 			return;
307 		}
308 		if (itos != oitos) {
309 			ip6->ip6_flow &= ~htonl(0xff << 20);
310 			ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
311 		}
312 		break;
313 	    }
314 #endif /* INET6 */
315  	case IPPROTO_ETHERIP:
316  		af = AF_LINK;
317  		break;
318 
319 	default:
320 		ipstat.ips_nogif++;
321 		m_freem(m);
322 		return;
323 	}
324 	gif_input(m, af, gifp);
325 	return;
326 }
327 
328 /*
329  * validate outer address.
330  */
331 static int
332 gif_validate4(const struct ip *ip, struct gif_softc *sc, struct ifnet *ifp)
333 {
334 	struct sockaddr_in *src, *dst;
335 	struct in_ifaddr *ia4;
336 
337 	src = (struct sockaddr_in *)sc->gif_psrc;
338 	dst = (struct sockaddr_in *)sc->gif_pdst;
339 
340 	/* check for address match */
341 	if (src->sin_addr.s_addr != ip->ip_dst.s_addr ||
342 	    dst->sin_addr.s_addr != ip->ip_src.s_addr)
343 		return 0;
344 
345 	/* martian filters on outer source - NOT done in ip_input! */
346 	if (IN_MULTICAST(ntohl(ip->ip_src.s_addr)))
347 		return 0;
348 	switch ((ntohl(ip->ip_src.s_addr) & 0xff000000) >> 24) {
349 	case 0: case 127: case 255:
350 		return 0;
351 	}
352 	/* reject packets with broadcast on source */
353 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_link) {
354 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
355 			continue;
356 		if (ip->ip_src.s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
357 			return 0;
358 	}
359 
360 	/* ingress filters on outer source */
361 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
362 		struct sockaddr_in sin;
363 		struct rtentry *rt;
364 
365 		bzero(&sin, sizeof(sin));
366 		sin.sin_family = AF_INET;
367 		sin.sin_len = sizeof(struct sockaddr_in);
368 		sin.sin_addr = ip->ip_src;
369 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
370 		if (!rt || rt->rt_ifp != ifp) {
371 #if 0
372 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
373 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
374 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
375 #endif
376 			if (rt)
377 				rtfree(rt);
378 			return 0;
379 		}
380 		rtfree(rt);
381 	}
382 
383 	return 32 * 2;
384 }
385 
386 /*
387  * we know that we are in IFF_UP, outer address available, and outer family
388  * matched the physical addr family.  see gif_encapcheck().
389  */
390 int
391 gif_encapcheck4(const struct mbuf *m, int off, int proto, void *arg)
392 {
393 	struct ip ip;
394 	struct gif_softc *sc;
395 	struct ifnet *ifp;
396 
397 	/* sanity check done in caller */
398 	sc = (struct gif_softc *)arg;
399 
400 	/* LINTED const cast */
401 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
402 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
403 
404 	return gif_validate4(&ip, sc, ifp);
405 }
406 
407 int
408 in_gif_attach(struct gif_softc *sc)
409 {
410 	sc->encap_cookie4 = encap_attach_func(AF_INET, -1, gif_encapcheck,
411 	    &in_gif_protosw, sc);
412 	if (sc->encap_cookie4 == NULL)
413 		return EEXIST;
414 	return 0;
415 }
416 
417 int
418 in_gif_detach(struct gif_softc *sc)
419 {
420 	int error;
421 
422 	error = encap_detach(sc->encap_cookie4);
423 	if (error == 0)
424 		sc->encap_cookie4 = NULL;
425 	return error;
426 }
427