xref: /freebsd/sys/netinet6/in6_gif.c (revision 884a2a699669ec61e2366e3e358342dbc94be24a) 
1 /*-
2  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the project nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	$KAME: in6_gif.c,v 1.49 2001/05/14 14:02:17 itojun Exp $
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include "opt_inet.h"
36 #include "opt_inet6.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/mbuf.h>
43 #include <sys/errno.h>
44 #include <sys/kernel.h>
45 #include <sys/queue.h>
46 #include <sys/syslog.h>
47 #include <sys/sysctl.h>
48 #include <sys/protosw.h>
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 #ifdef INET
57 #include <netinet/ip.h>
58 #endif
59 #include <netinet/ip_encap.h>
60 #ifdef INET6
61 #include <netinet/ip6.h>
62 #include <netinet6/ip6_var.h>
63 #include <netinet6/in6_gif.h>
64 #include <netinet6/in6_var.h>
65 #endif
66 #include <netinet6/ip6protosw.h>
67 #include <netinet/ip_ecn.h>
68 #ifdef INET6
69 #include <netinet6/ip6_ecn.h>
70 #endif
71 
72 #include <net/if_gif.h>
73 
74 VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
75 #define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
76 
77 SYSCTL_DECL(_net_inet6_ip6);
78 SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
79     &VNET_NAME(ip6_gif_hlim), 0, "");
80 
81 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
82 			 struct ifnet *);
83 
84 extern  struct domain inet6domain;
85 struct ip6protosw in6_gif_protosw = {
86 	.pr_type =	SOCK_RAW,
87 	.pr_domain =	&inet6domain,
88 	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
89 	.pr_flags =	PR_ATOMIC|PR_ADDR,
90 	.pr_input =	in6_gif_input,
91 	.pr_output =	rip6_output,
92 	.pr_ctloutput =	rip6_ctloutput,
93 	.pr_usrreqs =	&rip6_usrreqs
94 };
95 
96 int
97 in6_gif_output(struct ifnet *ifp,
98     int family,			/* family of the packet to be encapsulate */
99     struct mbuf *m)
100 {
101 	struct gif_softc *sc = ifp->if_softc;
102 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
103 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
104 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
105 	struct ip6_hdr *ip6;
106 	struct etherip_header eiphdr;
107 	int error, len, proto;
108 	u_int8_t itos, otos;
109 
110 	GIF_LOCK_ASSERT(sc);
111 
112 	if (sin6_src == NULL || sin6_dst == NULL ||
113 	    sin6_src->sin6_family != AF_INET6 ||
114 	    sin6_dst->sin6_family != AF_INET6) {
115 		m_freem(m);
116 		return EAFNOSUPPORT;
117 	}
118 
119 	switch (family) {
120 #ifdef INET
121 	case AF_INET:
122 	    {
123 		struct ip *ip;
124 
125 		proto = IPPROTO_IPV4;
126 		if (m->m_len < sizeof(*ip)) {
127 			m = m_pullup(m, sizeof(*ip));
128 			if (!m)
129 				return ENOBUFS;
130 		}
131 		ip = mtod(m, struct ip *);
132 		itos = ip->ip_tos;
133 		break;
134 	    }
135 #endif
136 #ifdef INET6
137 	case AF_INET6:
138 	    {
139 		struct ip6_hdr *ip6;
140 		proto = IPPROTO_IPV6;
141 		if (m->m_len < sizeof(*ip6)) {
142 			m = m_pullup(m, sizeof(*ip6));
143 			if (!m)
144 				return ENOBUFS;
145 		}
146 		ip6 = mtod(m, struct ip6_hdr *);
147 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
148 		break;
149 	    }
150 #endif
151 	case AF_LINK:
152 		proto = IPPROTO_ETHERIP;
153 
154 		/*
155 		 * GIF_SEND_REVETHIP (disabled by default) intentionally
156 		 * sends an EtherIP packet with revered version field in
157 		 * the header.  This is a knob for backward compatibility
158 		 * with FreeBSD 7.2R or prior.
159 		 */
160 		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
161 			eiphdr.eip_ver = 0;
162 			eiphdr.eip_resvl = ETHERIP_VERSION;
163 			eiphdr.eip_resvh = 0;
164 		} else {
165 			eiphdr.eip_ver = ETHERIP_VERSION;
166 			eiphdr.eip_resvl = 0;
167 			eiphdr.eip_resvh = 0;
168 		}
169 		/* prepend Ethernet-in-IP header */
170 		M_PREPEND(m, sizeof(struct etherip_header), M_DONTWAIT);
171 		if (m && m->m_len < sizeof(struct etherip_header))
172 			m = m_pullup(m, sizeof(struct etherip_header));
173 		if (m == NULL)
174 			return ENOBUFS;
175 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
176 		    sizeof(struct etherip_header));
177 		break;
178 
179 	default:
180 #ifdef DEBUG
181 		printf("in6_gif_output: warning: unknown family %d passed\n",
182 			family);
183 #endif
184 		m_freem(m);
185 		return EAFNOSUPPORT;
186 	}
187 
188 	/* prepend new IP header */
189 	len = sizeof(struct ip6_hdr);
190 #ifndef __NO_STRICT_ALIGNMENT
191 	if (family == AF_LINK)
192 		len += ETHERIP_ALIGN;
193 #endif
194 	M_PREPEND(m, len, M_DONTWAIT);
195 	if (m != NULL && m->m_len < len)
196 		m = m_pullup(m, len);
197 	if (m == NULL) {
198 		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
199 		return ENOBUFS;
200 	}
201 #ifndef __NO_STRICT_ALIGNMENT
202 	if (family == AF_LINK) {
203 		len = mtod(m, vm_offset_t) & 3;
204 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
205 		    ("in6_gif_output: unexpected misalignment"));
206 		m->m_data += len;
207 		m->m_len -= ETHERIP_ALIGN;
208 	}
209 #endif
210 
211 	ip6 = mtod(m, struct ip6_hdr *);
212 	ip6->ip6_flow	= 0;
213 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
214 	ip6->ip6_vfc	|= IPV6_VERSION;
215 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
216 	ip6->ip6_nxt	= proto;
217 	ip6->ip6_hlim	= V_ip6_gif_hlim;
218 	ip6->ip6_src	= sin6_src->sin6_addr;
219 	/* bidirectional configured tunnel mode */
220 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
221 		ip6->ip6_dst = sin6_dst->sin6_addr;
222 	else  {
223 		m_freem(m);
224 		return ENETUNREACH;
225 	}
226 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
227 		       &otos, &itos);
228 	ip6->ip6_flow &= ~htonl(0xff << 20);
229 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
230 
231 	if (dst->sin6_family != sin6_dst->sin6_family ||
232 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
233 		/* cache route doesn't match */
234 		bzero(dst, sizeof(*dst));
235 		dst->sin6_family = sin6_dst->sin6_family;
236 		dst->sin6_len = sizeof(struct sockaddr_in6);
237 		dst->sin6_addr = sin6_dst->sin6_addr;
238 		if (sc->gif_ro6.ro_rt) {
239 			RTFREE(sc->gif_ro6.ro_rt);
240 			sc->gif_ro6.ro_rt = NULL;
241 		}
242 #if 0
243 		GIF2IFP(sc)->if_mtu = GIF_MTU;
244 #endif
245 	}
246 
247 	if (sc->gif_ro6.ro_rt == NULL) {
248 		rtalloc((struct route *)&sc->gif_ro6);
249 		if (sc->gif_ro6.ro_rt == NULL) {
250 			m_freem(m);
251 			return ENETUNREACH;
252 		}
253 
254 		/* if it constitutes infinite encapsulation, punt. */
255 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
256 			m_freem(m);
257 			return ENETUNREACH;	/*XXX*/
258 		}
259 #if 0
260 		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
261 			- sizeof(struct ip6_hdr);
262 #endif
263 	}
264 
265 #ifdef IPV6_MINMTU
266 	/*
267 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
268 	 * it is too painful to ask for resend of inner packet, to achieve
269 	 * path MTU discovery for encapsulated packets.
270 	 */
271 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
272 #else
273 	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
274 #endif
275 
276 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
277 	    sc->gif_ro6.ro_rt != NULL) {
278 		RTFREE(sc->gif_ro6.ro_rt);
279 		sc->gif_ro6.ro_rt = NULL;
280 	}
281 
282 	return (error);
283 }
284 
285 int
286 in6_gif_input(struct mbuf **mp, int *offp, int proto)
287 {
288 	struct mbuf *m = *mp;
289 	struct ifnet *gifp = NULL;
290 	struct gif_softc *sc;
291 	struct ip6_hdr *ip6;
292 	int af = 0;
293 	u_int32_t otos;
294 
295 	ip6 = mtod(m, struct ip6_hdr *);
296 
297 	sc = (struct gif_softc *)encap_getarg(m);
298 	if (sc == NULL) {
299 		m_freem(m);
300 		V_ip6stat.ip6s_nogif++;
301 		return IPPROTO_DONE;
302 	}
303 
304 	gifp = GIF2IFP(sc);
305 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
306 		m_freem(m);
307 		V_ip6stat.ip6s_nogif++;
308 		return IPPROTO_DONE;
309 	}
310 
311 	otos = ip6->ip6_flow;
312 	m_adj(m, *offp);
313 
314 	switch (proto) {
315 #ifdef INET
316 	case IPPROTO_IPV4:
317 	    {
318 		struct ip *ip;
319 		u_int8_t otos8;
320 		af = AF_INET;
321 		otos8 = (ntohl(otos) >> 20) & 0xff;
322 		if (m->m_len < sizeof(*ip)) {
323 			m = m_pullup(m, sizeof(*ip));
324 			if (!m)
325 				return IPPROTO_DONE;
326 		}
327 		ip = mtod(m, struct ip *);
328 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
329 				  ECN_ALLOWED : ECN_NOCARE,
330 				  &otos8, &ip->ip_tos) == 0) {
331 			m_freem(m);
332 			return IPPROTO_DONE;
333 		}
334 		break;
335 	    }
336 #endif /* INET */
337 #ifdef INET6
338 	case IPPROTO_IPV6:
339 	    {
340 		struct ip6_hdr *ip6;
341 		af = AF_INET6;
342 		if (m->m_len < sizeof(*ip6)) {
343 			m = m_pullup(m, sizeof(*ip6));
344 			if (!m)
345 				return IPPROTO_DONE;
346 		}
347 		ip6 = mtod(m, struct ip6_hdr *);
348 		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
349 				   ECN_ALLOWED : ECN_NOCARE,
350 				   &otos, &ip6->ip6_flow) == 0) {
351 			m_freem(m);
352 			return IPPROTO_DONE;
353 		}
354 		break;
355 	    }
356 #endif
357 	case IPPROTO_ETHERIP:
358 		af = AF_LINK;
359 		break;
360 
361 	default:
362 		V_ip6stat.ip6s_nogif++;
363 		m_freem(m);
364 		return IPPROTO_DONE;
365 	}
366 
367 	gif_input(m, af, gifp);
368 	return IPPROTO_DONE;
369 }
370 
371 /*
372  * validate outer address.
373  */
374 static int
375 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
376     struct ifnet *ifp)
377 {
378 	struct sockaddr_in6 *src, *dst;
379 
380 	src = (struct sockaddr_in6 *)sc->gif_psrc;
381 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
382 
383 	/*
384 	 * Check for address match.  Note that the check is for an incoming
385 	 * packet.  We should compare the *source* address in our configuration
386 	 * and the *destination* address of the packet, and vice versa.
387 	 */
388 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
389 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
390 		return 0;
391 
392 	/* martian filters on outer source - done in ip6_input */
393 
394 	/* ingress filters on outer source */
395 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
396 		struct sockaddr_in6 sin6;
397 		struct rtentry *rt;
398 
399 		bzero(&sin6, sizeof(sin6));
400 		sin6.sin6_family = AF_INET6;
401 		sin6.sin6_len = sizeof(struct sockaddr_in6);
402 		sin6.sin6_addr = ip6->ip6_src;
403 		sin6.sin6_scope_id = 0; /* XXX */
404 
405 		rt = rtalloc1((struct sockaddr *)&sin6, 0, 0UL);
406 		if (!rt || rt->rt_ifp != ifp) {
407 #if 0
408 			char ip6buf[INET6_ADDRSTRLEN];
409 			log(LOG_WARNING, "%s: packet from %s dropped "
410 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
411 			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
412 #endif
413 			if (rt)
414 				RTFREE_LOCKED(rt);
415 			return 0;
416 		}
417 		RTFREE_LOCKED(rt);
418 	}
419 
420 	return 128 * 2;
421 }
422 
423 /*
424  * we know that we are in IFF_UP, outer address available, and outer family
425  * matched the physical addr family.  see gif_encapcheck().
426  * sanity check for arg should have been done in the caller.
427  */
428 int
429 gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
430 {
431 	struct ip6_hdr ip6;
432 	struct gif_softc *sc;
433 	struct ifnet *ifp;
434 
435 	/* sanity check done in caller */
436 	sc = (struct gif_softc *)arg;
437 
438 	/* LINTED const cast */
439 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
440 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
441 
442 	return gif_validate6(&ip6, sc, ifp);
443 }
444 
445 int
446 in6_gif_attach(struct gif_softc *sc)
447 {
448 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
449 	    (void *)&in6_gif_protosw, sc);
450 	if (sc->encap_cookie6 == NULL)
451 		return EEXIST;
452 	return 0;
453 }
454 
455 int
456 in6_gif_detach(struct gif_softc *sc)
457 {
458 	int error;
459 
460 	error = encap_detach(sc->encap_cookie6);
461 	if (error == 0)
462 		sc->encap_cookie6 = NULL;
463 	return error;
464 }
465