xref: /freebsd/sys/netinet6/in6_gif.c (revision 6186fd1857626de0f7cb1a9e4dff19082f9ebb11) 
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/if_var.h>
53 #include <net/route.h>
54 #include <net/vnet.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/in_systm.h>
58 #ifdef INET
59 #include <netinet/ip.h>
60 #endif
61 #include <netinet/ip_encap.h>
62 #ifdef INET6
63 #include <netinet/ip6.h>
64 #include <netinet6/ip6_var.h>
65 #include <netinet6/in6_gif.h>
66 #include <netinet6/in6_var.h>
67 #endif
68 #include <netinet/ip_ecn.h>
69 #ifdef INET6
70 #include <netinet6/ip6_ecn.h>
71 #endif
72 
73 #include <net/if_gif.h>
74 
75 VNET_DEFINE(int, ip6_gif_hlim) = GIF_HLIM;
76 #define	V_ip6_gif_hlim			VNET(ip6_gif_hlim)
77 
78 SYSCTL_DECL(_net_inet6_ip6);
79 SYSCTL_VNET_INT(_net_inet6_ip6, IPV6CTL_GIF_HLIM, gifhlim, CTLFLAG_RW,
80     &VNET_NAME(ip6_gif_hlim), 0, "");
81 
82 static int gif_validate6(const struct ip6_hdr *, struct gif_softc *,
83 			 struct ifnet *);
84 
85 extern  struct domain inet6domain;
86 struct protosw in6_gif_protosw = {
87 	.pr_type =	SOCK_RAW,
88 	.pr_domain =	&inet6domain,
89 	.pr_protocol =	0,			/* IPPROTO_IPV[46] */
90 	.pr_flags =	PR_ATOMIC|PR_ADDR,
91 	.pr_input =	in6_gif_input,
92 	.pr_output =	rip6_output,
93 	.pr_ctloutput =	rip6_ctloutput,
94 	.pr_usrreqs =	&rip6_usrreqs
95 };
96 
97 int
98 in6_gif_output(struct ifnet *ifp,
99     int family,			/* family of the packet to be encapsulate */
100     struct mbuf *m)
101 {
102 	struct gif_softc *sc = ifp->if_softc;
103 	struct sockaddr_in6 *dst = (struct sockaddr_in6 *)&sc->gif_ro6.ro_dst;
104 	struct sockaddr_in6 *sin6_src = (struct sockaddr_in6 *)sc->gif_psrc;
105 	struct sockaddr_in6 *sin6_dst = (struct sockaddr_in6 *)sc->gif_pdst;
106 	struct ip6_hdr *ip6;
107 	struct etherip_header eiphdr;
108 	int error, len, proto;
109 	u_int8_t itos, otos;
110 
111 	GIF_LOCK_ASSERT(sc);
112 
113 	if (sin6_src == NULL || sin6_dst == NULL ||
114 	    sin6_src->sin6_family != AF_INET6 ||
115 	    sin6_dst->sin6_family != AF_INET6) {
116 		m_freem(m);
117 		return EAFNOSUPPORT;
118 	}
119 
120 	switch (family) {
121 #ifdef INET
122 	case AF_INET:
123 	    {
124 		struct ip *ip;
125 
126 		proto = IPPROTO_IPV4;
127 		if (m->m_len < sizeof(*ip)) {
128 			m = m_pullup(m, sizeof(*ip));
129 			if (!m)
130 				return ENOBUFS;
131 		}
132 		ip = mtod(m, struct ip *);
133 		itos = ip->ip_tos;
134 		break;
135 	    }
136 #endif
137 #ifdef INET6
138 	case AF_INET6:
139 	    {
140 		struct ip6_hdr *ip6;
141 		proto = IPPROTO_IPV6;
142 		if (m->m_len < sizeof(*ip6)) {
143 			m = m_pullup(m, sizeof(*ip6));
144 			if (!m)
145 				return ENOBUFS;
146 		}
147 		ip6 = mtod(m, struct ip6_hdr *);
148 		itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
149 		break;
150 	    }
151 #endif
152 	case AF_LINK:
153 		proto = IPPROTO_ETHERIP;
154 
155 		/*
156 		 * GIF_SEND_REVETHIP (disabled by default) intentionally
157 		 * sends an EtherIP packet with revered version field in
158 		 * the header.  This is a knob for backward compatibility
159 		 * with FreeBSD 7.2R or prior.
160 		 */
161 		if ((sc->gif_options & GIF_SEND_REVETHIP)) {
162 			eiphdr.eip_ver = 0;
163 			eiphdr.eip_resvl = ETHERIP_VERSION;
164 			eiphdr.eip_resvh = 0;
165 		} else {
166 			eiphdr.eip_ver = ETHERIP_VERSION;
167 			eiphdr.eip_resvl = 0;
168 			eiphdr.eip_resvh = 0;
169 		}
170 		/* prepend Ethernet-in-IP header */
171 		M_PREPEND(m, sizeof(struct etherip_header), M_NOWAIT);
172 		if (m && m->m_len < sizeof(struct etherip_header))
173 			m = m_pullup(m, sizeof(struct etherip_header));
174 		if (m == NULL)
175 			return ENOBUFS;
176 		bcopy(&eiphdr, mtod(m, struct etherip_header *),
177 		    sizeof(struct etherip_header));
178 		itos = 0;
179 		break;
180 
181 	default:
182 #ifdef DEBUG
183 		printf("in6_gif_output: warning: unknown family %d passed\n",
184 			family);
185 #endif
186 		m_freem(m);
187 		return EAFNOSUPPORT;
188 	}
189 
190 	/* prepend new IP header */
191 	len = sizeof(struct ip6_hdr);
192 #ifndef __NO_STRICT_ALIGNMENT
193 	if (family == AF_LINK)
194 		len += ETHERIP_ALIGN;
195 #endif
196 	M_PREPEND(m, len, M_NOWAIT);
197 	if (m != NULL && m->m_len < len)
198 		m = m_pullup(m, len);
199 	if (m == NULL) {
200 		printf("ENOBUFS in in6_gif_output %d\n", __LINE__);
201 		return ENOBUFS;
202 	}
203 #ifndef __NO_STRICT_ALIGNMENT
204 	if (family == AF_LINK) {
205 		len = mtod(m, vm_offset_t) & 3;
206 		KASSERT(len == 0 || len == ETHERIP_ALIGN,
207 		    ("in6_gif_output: unexpected misalignment"));
208 		m->m_data += len;
209 		m->m_len -= ETHERIP_ALIGN;
210 	}
211 #endif
212 
213 	ip6 = mtod(m, struct ip6_hdr *);
214 	ip6->ip6_flow	= 0;
215 	ip6->ip6_vfc	&= ~IPV6_VERSION_MASK;
216 	ip6->ip6_vfc	|= IPV6_VERSION;
217 	ip6->ip6_plen	= htons((u_short)m->m_pkthdr.len);
218 	ip6->ip6_nxt	= proto;
219 	ip6->ip6_hlim	= V_ip6_gif_hlim;
220 	ip6->ip6_src	= sin6_src->sin6_addr;
221 	/* bidirectional configured tunnel mode */
222 	if (!IN6_IS_ADDR_UNSPECIFIED(&sin6_dst->sin6_addr))
223 		ip6->ip6_dst = sin6_dst->sin6_addr;
224 	else  {
225 		m_freem(m);
226 		return ENETUNREACH;
227 	}
228 	ip_ecn_ingress((ifp->if_flags & IFF_LINK1) ? ECN_ALLOWED : ECN_NOCARE,
229 		       &otos, &itos);
230 	ip6->ip6_flow &= ~htonl(0xff << 20);
231 	ip6->ip6_flow |= htonl((u_int32_t)otos << 20);
232 
233 	M_SETFIB(m, sc->gif_fibnum);
234 
235 	if (dst->sin6_family != sin6_dst->sin6_family ||
236 	     !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &sin6_dst->sin6_addr)) {
237 		/* cache route doesn't match */
238 		bzero(dst, sizeof(*dst));
239 		dst->sin6_family = sin6_dst->sin6_family;
240 		dst->sin6_len = sizeof(struct sockaddr_in6);
241 		dst->sin6_addr = sin6_dst->sin6_addr;
242 		if (sc->gif_ro6.ro_rt) {
243 			RTFREE(sc->gif_ro6.ro_rt);
244 			sc->gif_ro6.ro_rt = NULL;
245 		}
246 #if 0
247 		GIF2IFP(sc)->if_mtu = GIF_MTU;
248 #endif
249 	}
250 
251 	if (sc->gif_ro6.ro_rt == NULL) {
252 		in6_rtalloc(&sc->gif_ro6, sc->gif_fibnum);
253 		if (sc->gif_ro6.ro_rt == NULL) {
254 			m_freem(m);
255 			return ENETUNREACH;
256 		}
257 
258 		/* if it constitutes infinite encapsulation, punt. */
259 		if (sc->gif_ro.ro_rt->rt_ifp == ifp) {
260 			m_freem(m);
261 			return ENETUNREACH;	/*XXX*/
262 		}
263 #if 0
264 		ifp->if_mtu = sc->gif_ro6.ro_rt->rt_ifp->if_mtu
265 			- sizeof(struct ip6_hdr);
266 #endif
267 	}
268 
269 	m->m_flags &= ~(M_BCAST|M_MCAST);
270 #ifdef IPV6_MINMTU
271 	/*
272 	 * force fragmentation to minimum MTU, to avoid path MTU discovery.
273 	 * it is too painful to ask for resend of inner packet, to achieve
274 	 * path MTU discovery for encapsulated packets.
275 	 */
276 	error = ip6_output(m, 0, &sc->gif_ro6, IPV6_MINMTU, 0, NULL, NULL);
277 #else
278 	error = ip6_output(m, 0, &sc->gif_ro6, 0, 0, NULL, NULL);
279 #endif
280 
281 	if (!(GIF2IFP(sc)->if_flags & IFF_LINK0) &&
282 	    sc->gif_ro6.ro_rt != NULL) {
283 		RTFREE(sc->gif_ro6.ro_rt);
284 		sc->gif_ro6.ro_rt = NULL;
285 	}
286 
287 	return (error);
288 }
289 
290 int
291 in6_gif_input(struct mbuf **mp, int *offp, int proto)
292 {
293 	struct mbuf *m = *mp;
294 	struct ifnet *gifp = NULL;
295 	struct gif_softc *sc;
296 	struct ip6_hdr *ip6;
297 	int af = 0;
298 	u_int32_t otos;
299 
300 	ip6 = mtod(m, struct ip6_hdr *);
301 
302 	sc = (struct gif_softc *)encap_getarg(m);
303 	if (sc == NULL) {
304 		m_freem(m);
305 		IP6STAT_INC(ip6s_nogif);
306 		return IPPROTO_DONE;
307 	}
308 
309 	gifp = GIF2IFP(sc);
310 	if (gifp == NULL || (gifp->if_flags & IFF_UP) == 0) {
311 		m_freem(m);
312 		IP6STAT_INC(ip6s_nogif);
313 		return IPPROTO_DONE;
314 	}
315 
316 	otos = ip6->ip6_flow;
317 	m_adj(m, *offp);
318 
319 	switch (proto) {
320 #ifdef INET
321 	case IPPROTO_IPV4:
322 	    {
323 		struct ip *ip;
324 		u_int8_t otos8;
325 		af = AF_INET;
326 		otos8 = (ntohl(otos) >> 20) & 0xff;
327 		if (m->m_len < sizeof(*ip)) {
328 			m = m_pullup(m, sizeof(*ip));
329 			if (!m)
330 				return IPPROTO_DONE;
331 		}
332 		ip = mtod(m, struct ip *);
333 		if (ip_ecn_egress((gifp->if_flags & IFF_LINK1) ?
334 				  ECN_ALLOWED : ECN_NOCARE,
335 				  &otos8, &ip->ip_tos) == 0) {
336 			m_freem(m);
337 			return IPPROTO_DONE;
338 		}
339 		break;
340 	    }
341 #endif /* INET */
342 #ifdef INET6
343 	case IPPROTO_IPV6:
344 	    {
345 		struct ip6_hdr *ip6;
346 		af = AF_INET6;
347 		if (m->m_len < sizeof(*ip6)) {
348 			m = m_pullup(m, sizeof(*ip6));
349 			if (!m)
350 				return IPPROTO_DONE;
351 		}
352 		ip6 = mtod(m, struct ip6_hdr *);
353 		if (ip6_ecn_egress((gifp->if_flags & IFF_LINK1) ?
354 				   ECN_ALLOWED : ECN_NOCARE,
355 				   &otos, &ip6->ip6_flow) == 0) {
356 			m_freem(m);
357 			return IPPROTO_DONE;
358 		}
359 		break;
360 	    }
361 #endif
362 	case IPPROTO_ETHERIP:
363 		af = AF_LINK;
364 		break;
365 
366 	default:
367 		IP6STAT_INC(ip6s_nogif);
368 		m_freem(m);
369 		return IPPROTO_DONE;
370 	}
371 
372 	gif_input(m, af, gifp);
373 	return IPPROTO_DONE;
374 }
375 
376 /*
377  * validate outer address.
378  */
379 static int
380 gif_validate6(const struct ip6_hdr *ip6, struct gif_softc *sc,
381     struct ifnet *ifp)
382 {
383 	struct sockaddr_in6 *src, *dst;
384 
385 	src = (struct sockaddr_in6 *)sc->gif_psrc;
386 	dst = (struct sockaddr_in6 *)sc->gif_pdst;
387 
388 	/*
389 	 * Check for address match.  Note that the check is for an incoming
390 	 * packet.  We should compare the *source* address in our configuration
391 	 * and the *destination* address of the packet, and vice versa.
392 	 */
393 	if (!IN6_ARE_ADDR_EQUAL(&src->sin6_addr, &ip6->ip6_dst) ||
394 	    !IN6_ARE_ADDR_EQUAL(&dst->sin6_addr, &ip6->ip6_src))
395 		return 0;
396 
397 	/* martian filters on outer source - done in ip6_input */
398 
399 	/* ingress filters on outer source */
400 	if ((GIF2IFP(sc)->if_flags & IFF_LINK2) == 0 && ifp) {
401 		struct sockaddr_in6 sin6;
402 		struct rtentry *rt;
403 
404 		bzero(&sin6, sizeof(sin6));
405 		sin6.sin6_family = AF_INET6;
406 		sin6.sin6_len = sizeof(struct sockaddr_in6);
407 		sin6.sin6_addr = ip6->ip6_src;
408 		sin6.sin6_scope_id = 0; /* XXX */
409 
410 		rt = in6_rtalloc1((struct sockaddr *)&sin6, 0, 0UL,
411 		    sc->gif_fibnum);
412 		if (!rt || rt->rt_ifp != ifp) {
413 #if 0
414 			char ip6buf[INET6_ADDRSTRLEN];
415 			log(LOG_WARNING, "%s: packet from %s dropped "
416 			    "due to ingress filter\n", if_name(GIF2IFP(sc)),
417 			    ip6_sprintf(ip6buf, &sin6.sin6_addr));
418 #endif
419 			if (rt)
420 				RTFREE_LOCKED(rt);
421 			return 0;
422 		}
423 		RTFREE_LOCKED(rt);
424 	}
425 
426 	return 128 * 2;
427 }
428 
429 /*
430  * we know that we are in IFF_UP, outer address available, and outer family
431  * matched the physical addr family.  see gif_encapcheck().
432  * sanity check for arg should have been done in the caller.
433  */
434 int
435 gif_encapcheck6(const struct mbuf *m, int off, int proto, void *arg)
436 {
437 	struct ip6_hdr ip6;
438 	struct gif_softc *sc;
439 	struct ifnet *ifp;
440 
441 	/* sanity check done in caller */
442 	sc = (struct gif_softc *)arg;
443 
444 	/* LINTED const cast */
445 	m_copydata(m, 0, sizeof(ip6), (caddr_t)&ip6);
446 	ifp = ((m->m_flags & M_PKTHDR) != 0) ? m->m_pkthdr.rcvif : NULL;
447 
448 	return gif_validate6(&ip6, sc, ifp);
449 }
450 
451 int
452 in6_gif_attach(struct gif_softc *sc)
453 {
454 	sc->encap_cookie6 = encap_attach_func(AF_INET6, -1, gif_encapcheck,
455 	    (void *)&in6_gif_protosw, sc);
456 	if (sc->encap_cookie6 == NULL)
457 		return EEXIST;
458 	return 0;
459 }
460 
461 int
462 in6_gif_detach(struct gif_softc *sc)
463 {
464 	int error;
465 
466 	error = encap_detach(sc->encap_cookie6);
467 	if (error == 0)
468 		sc->encap_cookie6 = NULL;
469 	return error;
470 }
471