xref: /netbsd-src/sys/net/if_stf.c (revision 3b01aba77a7a698587faaae455bbfe740923c1f5)
1 /*	$NetBSD: if_stf.c,v 1.17 2001/07/18 16:43:10 thorpej Exp $	*/
2 /*	$KAME: if_stf.c,v 1.62 2001/06/07 22:32:16 itojun Exp $	*/
3 
4 /*
5  * Copyright (C) 2000 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 /*
34  * 6to4 interface, based on RFC3056.
35  *
36  * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting.
37  * There is no address mapping defined from IPv6 multicast address to IPv4
38  * address.  Therefore, we do not have IFF_MULTICAST on the interface.
39  *
40  * Due to the lack of address mapping for link-local addresses, we cannot
41  * throw packets toward link-local addresses (fe80::x).  Also, we cannot throw
42  * packets to link-local multicast addresses (ff02::x).
43  *
44  * Here are interesting symptoms due to the lack of link-local address:
45  *
46  * Unicast routing exchange:
47  * - RIPng: Impossible.  Uses link-local multicast packet toward ff02::9,
48  *   and link-local addresses as nexthop.
49  * - OSPFv6: Impossible.  OSPFv6 assumes that there's link-local address
50  *   assigned to the link, and makes use of them.  Also, HELLO packets use
51  *   link-local multicast addresses (ff02::5 and ff02::6).
52  * - BGP4+: Maybe.  You can only use global address as nexthop, and global
53  *   address as TCP endpoint address.
54  *
55  * Multicast routing protocols:
56  * - PIM: Hello packet cannot be used to discover adjacent PIM routers.
57  *   Adjacent PIM routers must be configured manually (is it really spec-wise
58  *   correct thing to do?).
59  *
60  * ICMPv6:
61  * - Redirects cannot be used due to the lack of link-local address.
62  *
63  * stf interface does not have, and will not need, a link-local address.
64  * It seems to have no real benefit and does not help the above symptoms much.
65  * Even if we assign link-locals to interface, we cannot really
66  * use link-local unicast/multicast on top of 6to4 cloud (since there's no
67  * encapsulation defined for link-local address), and the above analysis does
68  * not change.  RFC3056 does not mandate the assignment of link-local address
69  * either.
70  *
71  * 6to4 interface has security issues.  Refer to
72  * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt
73  * for details.  The code tries to filter out some of malicious packets.
74  * Note that there is no way to be 100% secure.
75  */
76 
77 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
78 #include "opt_inet.h"
79 #include "opt_inet6.h"
80 #endif
81 #ifdef __NetBSD__
82 #include "opt_inet.h"
83 #endif
84 
85 #include <sys/param.h>
86 #include <sys/systm.h>
87 #include <sys/socket.h>
88 #include <sys/sockio.h>
89 #include <sys/mbuf.h>
90 #include <sys/errno.h>
91 #if !(defined(__FreeBSD__) && __FreeBSD__ >= 3)
92 #include <sys/ioctl.h>
93 #endif
94 #include <sys/protosw.h>
95 #ifdef __FreeBSD__
96 #include <sys/kernel.h>
97 #endif
98 #include <sys/queue.h>
99 #include <sys/syslog.h>
100 #include <machine/cpu.h>
101 
102 #if defined(__FreeBSD__) && __FreeBSD__ >= 3
103 #include <sys/malloc.h>
104 #endif
105 
106 #include <net/if.h>
107 #include <net/route.h>
108 #include <net/netisr.h>
109 #include <net/if_types.h>
110 #include <net/if_stf.h>
111 
112 #include <netinet/in.h>
113 #include <netinet/in_systm.h>
114 #include <netinet/ip.h>
115 #include <netinet/ip_var.h>
116 #include <netinet/in_var.h>
117 
118 #include <netinet/ip6.h>
119 #include <netinet6/ip6_var.h>
120 #include <netinet6/in6_gif.h>
121 #include <netinet6/in6_var.h>
122 #include <netinet/ip_ecn.h>
123 
124 #include <netinet/ip_encap.h>
125 
126 #include <machine/stdarg.h>
127 
128 #include <net/net_osdep.h>
129 
130 #if defined(__FreeBSD__) && __FreeBSD__ >= 4
131 #include "bpf.h"
132 #define NBPFILTER	NBPF
133 #else
134 #include "bpfilter.h"
135 #endif
136 #include "stf.h"
137 #include "gif.h"	/*XXX*/
138 
139 #if NBPFILTER > 0
140 #include <net/bpf.h>
141 #endif
142 
143 #if NGIF > 0
144 #include <net/if_gif.h>
145 #endif
146 
147 #if NSTF > 0
148 
149 #define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
150 #define GET_V4(x)	((struct in_addr *)(&(x)->s6_addr16[1]))
151 
152 struct stf_softc {
153 	struct ifnet	sc_if;	   /* common area */
154 	union {
155 		struct route  __sc_ro4;
156 		struct route_in6 __sc_ro6; /* just for safety */
157 	} __sc_ro46;
158 #define sc_ro	__sc_ro46.__sc_ro4
159 	const struct encaptab *encap_cookie;
160 	LIST_ENTRY(stf_softc) sc_list;
161 };
162 
163 LIST_HEAD(, stf_softc) stf_softc_list;
164 
165 int	stf_clone_create __P((struct if_clone *, int));
166 void	stf_clone_destroy __P((struct ifnet *));
167 
168 struct if_clone stf_cloner =
169     IF_CLONE_INITIALIZER("stf", stf_clone_create, stf_clone_destroy);
170 
171 #if NGIF > 0
172 extern int ip_gif_ttl;	/*XXX*/
173 #else
174 static int ip_gif_ttl = 40;	/*XXX*/
175 #endif
176 
177 extern struct protosw in_stf_protosw;
178 
179 #ifdef __FreeBSD__
180 void stfattach __P((void *));
181 #else
182 void stfattach __P((int));
183 #endif
184 static int stf_encapcheck __P((const struct mbuf *, int, int, void *));
185 static struct in6_ifaddr *stf_getsrcifa6 __P((struct ifnet *));
186 static int stf_output __P((struct ifnet *, struct mbuf *, struct sockaddr *,
187 	struct rtentry *));
188 static int stf_checkaddr4 __P((struct stf_softc *, struct in_addr *,
189 	struct ifnet *));
190 static int stf_checkaddr6 __P((struct stf_softc *, struct in6_addr *,
191 	struct ifnet *));
192 static void stf_rtrequest __P((int, struct rtentry *, struct rt_addrinfo *));
193 #if defined(__FreeBSD__) && __FreeBSD__ < 3
194 static int stf_ioctl __P((struct ifnet *, int, caddr_t));
195 #else
196 static int stf_ioctl __P((struct ifnet *, u_long, caddr_t));
197 #endif
198 
199 /* ARGSUSED */
200 void
201 stfattach(count)
202 	int count;
203 {
204 
205 	LIST_INIT(&stf_softc_list);
206 	if_clone_attach(&stf_cloner);
207 }
208 
209 int
210 stf_clone_create(ifc, unit)
211 	struct if_clone *ifc;
212 	int unit;
213 {
214 	struct stf_softc *sc;
215 
216 	if (LIST_FIRST(&stf_softc_list) != NULL) {
217 		/* Only one stf interface is allowed. */
218 		return (EEXIST);
219 	}
220 
221 	sc = malloc(sizeof(struct stf_softc), M_DEVBUF, M_WAIT);
222 	memset(sc, 0, sizeof(struct stf_softc));
223 
224 	sprintf(sc->sc_if.if_xname, "%s%d", ifc->ifc_name, unit);
225 
226 	sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
227 	    stf_encapcheck, &in_stf_protosw, sc);
228 	if (sc->encap_cookie == NULL) {
229 		printf("%s: unable to attach encap\n", if_name(&sc->sc_if));
230 		free(sc, M_DEVBUF);
231 		return (EIO);	/* XXX */
232 	}
233 
234 	sc->sc_if.if_mtu    = IPV6_MMTU;
235 	sc->sc_if.if_flags  = 0;
236 	sc->sc_if.if_ioctl  = stf_ioctl;
237 	sc->sc_if.if_output = stf_output;
238 	sc->sc_if.if_type   = IFT_STF;
239 	sc->sc_if.if_dlt    = DLT_NULL;
240 #if defined(__FreeBSD__) && __FreeBSD__ >= 4
241 	sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
242 #endif
243 	if_attach(&sc->sc_if);
244 	if_alloc_sadl(&sc->sc_if);
245 #if NBPFILTER > 0
246 	bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
247 #endif
248 	LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
249 	return (0);
250 }
251 
252 void
253 stf_clone_destroy(ifp)
254 	struct ifnet *ifp;
255 {
256 	struct stf_softc *sc = (void *) ifp;
257 
258 	LIST_REMOVE(sc, sc_list);
259 	encap_detach(sc->encap_cookie);
260 #if NBPFILTER > 0
261 	bpfdetach(ifp);
262 #endif
263 	if_detach(ifp);
264 	free(sc, M_DEVBUF);
265 }
266 
267 #ifdef __FreeBSD__
268 PSEUDO_SET(stfattach, if_stf);
269 #endif
270 
271 static int
272 stf_encapcheck(m, off, proto, arg)
273 	const struct mbuf *m;
274 	int off;
275 	int proto;
276 	void *arg;
277 {
278 	struct ip ip;
279 	struct in6_ifaddr *ia6;
280 	struct stf_softc *sc;
281 	struct in_addr a, b;
282 
283 	sc = (struct stf_softc *)arg;
284 	if (sc == NULL)
285 		return 0;
286 
287 	if ((sc->sc_if.if_flags & IFF_UP) == 0)
288 		return 0;
289 
290 	/* IFF_LINK0 means "no decapsulation" */
291 	if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
292 		return 0;
293 
294 	if (proto != IPPROTO_IPV6)
295 		return 0;
296 
297 	/* LINTED const cast */
298 	m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
299 
300 	if (ip.ip_v != 4)
301 		return 0;
302 
303 	ia6 = stf_getsrcifa6(&sc->sc_if);
304 	if (ia6 == NULL)
305 		return 0;
306 
307 	/*
308 	 * check if IPv4 dst matches the IPv4 address derived from the
309 	 * local 6to4 address.
310 	 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
311 	 */
312 	if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
313 	    sizeof(ip.ip_dst)) != 0)
314 		return 0;
315 
316 	/*
317 	 * check if IPv4 src matches the IPv4 address derived from the
318 	 * local 6to4 address masked by prefixmask.
319 	 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
320 	 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
321 	 */
322 	memset(&a, 0, sizeof(a));
323 	a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
324 	a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
325 	b = ip.ip_src;
326 	b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
327 	if (a.s_addr != b.s_addr)
328 		return 0;
329 
330 	/* stf interface makes single side match only */
331 	return 32;
332 }
333 
334 static struct in6_ifaddr *
335 stf_getsrcifa6(ifp)
336 	struct ifnet *ifp;
337 {
338 	struct ifaddr *ia;
339 	struct in_ifaddr *ia4;
340 	struct sockaddr_in6 *sin6;
341 	struct in_addr in;
342 
343 #if defined(__bsdi__) || (defined(__FreeBSD__) && __FreeBSD__ < 3)
344 	for (ia = ifp->if_addrlist; ia; ia = ia->ifa_next)
345 #else
346 	for (ia = ifp->if_addrlist.tqh_first;
347 	     ia;
348 	     ia = ia->ifa_list.tqe_next)
349 #endif
350 	{
351 		if (ia->ifa_addr == NULL)
352 			continue;
353 		if (ia->ifa_addr->sa_family != AF_INET6)
354 			continue;
355 		sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
356 		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
357 			continue;
358 
359 		bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
360 #ifdef __NetBSD__
361 		INADDR_TO_IA(in, ia4);
362 #else
363 #ifdef __OpenBSD__
364 		for (ia4 = in_ifaddr.tqh_first;
365 		     ia4;
366 		     ia4 = ia4->ia_list.tqe_next)
367 #elif defined(__FreeBSD__) && __FreeBSD__ >= 3
368 		for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
369 		     ia4;
370 		     ia4 = TAILQ_NEXT(ia4, ia_link))
371 #else
372 		for (ia4 = in_ifaddr; ia4 != NULL; ia4 = ia4->ia_next)
373 #endif
374 		{
375 			if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
376 				break;
377 		}
378 #endif
379 		if (ia4 == NULL)
380 			continue;
381 
382 		return (struct in6_ifaddr *)ia;
383 	}
384 
385 	return NULL;
386 }
387 
388 static int
389 stf_output(ifp, m, dst, rt)
390 	struct ifnet *ifp;
391 	struct mbuf *m;
392 	struct sockaddr *dst;
393 	struct rtentry *rt;
394 {
395 	struct stf_softc *sc;
396 	struct sockaddr_in6 *dst6;
397 	struct in_addr *in4;
398 	struct sockaddr_in *dst4;
399 	u_int8_t tos;
400 	struct ip *ip;
401 	struct ip6_hdr *ip6;
402 	struct in6_ifaddr *ia6;
403 
404 	sc = (struct stf_softc*)ifp;
405 	dst6 = (struct sockaddr_in6 *)dst;
406 
407 	/* just in case */
408 	if ((ifp->if_flags & IFF_UP) == 0) {
409 		m_freem(m);
410 		return ENETDOWN;
411 	}
412 
413 	/*
414 	 * If we don't have an ip4 address that match my inner ip6 address,
415 	 * we shouldn't generate output.  Without this check, we'll end up
416 	 * using wrong IPv4 source.
417 	 */
418 	ia6 = stf_getsrcifa6(ifp);
419 	if (ia6 == NULL) {
420 		m_freem(m);
421 		return ENETDOWN;
422 	}
423 
424 	if (m->m_len < sizeof(*ip6)) {
425 		m = m_pullup(m, sizeof(*ip6));
426 		if (!m)
427 			return ENOBUFS;
428 	}
429 	ip6 = mtod(m, struct ip6_hdr *);
430 	tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
431 
432 	/*
433 	 * Pickup the right outer dst addr from the list of candidates.
434 	 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
435 	 */
436 	if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
437 		in4 = GET_V4(&ip6->ip6_dst);
438 	else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
439 		in4 = GET_V4(&dst6->sin6_addr);
440 	else {
441 		m_freem(m);
442 		return ENETUNREACH;
443 	}
444 
445 #if NBPFILTER > 0
446 	if (ifp->if_bpf) {
447 		/*
448 		 * We need to prepend the address family as
449 		 * a four byte field.  Cons up a dummy header
450 		 * to pacify bpf.  This is safe because bpf
451 		 * will only read from the mbuf (i.e., it won't
452 		 * try to free it or keep a pointer a to it).
453 		 */
454 		struct mbuf m0;
455 		u_int32_t af = AF_INET6;
456 
457 		m0.m_next = m;
458 		m0.m_len = 4;
459 		m0.m_data = (char *)&af;
460 
461 #ifdef HAVE_OLD_BPF
462 		bpf_mtap(ifp, &m0);
463 #else
464 		bpf_mtap(ifp->if_bpf, &m0);
465 #endif
466 	}
467 #endif /*NBPFILTER > 0*/
468 
469 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
470 	if (m && m->m_len < sizeof(struct ip))
471 		m = m_pullup(m, sizeof(struct ip));
472 	if (m == NULL)
473 		return ENOBUFS;
474 	ip = mtod(m, struct ip *);
475 
476 	memset(ip, 0, sizeof(*ip));
477 
478 	bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
479 	    &ip->ip_src, sizeof(ip->ip_src));
480 	bcopy(in4, &ip->ip_dst, sizeof(ip->ip_dst));
481 	ip->ip_p = IPPROTO_IPV6;
482 	ip->ip_ttl = ip_gif_ttl;	/*XXX*/
483 	ip->ip_len = m->m_pkthdr.len;	/*host order*/
484 	if (ifp->if_flags & IFF_LINK1)
485 		ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
486 	else
487 		ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
488 
489 	dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
490 	if (dst4->sin_family != AF_INET ||
491 	    bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
492 		/* cache route doesn't match */
493 		dst4->sin_family = AF_INET;
494 		dst4->sin_len = sizeof(struct sockaddr_in);
495 		bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
496 		if (sc->sc_ro.ro_rt) {
497 			RTFREE(sc->sc_ro.ro_rt);
498 			sc->sc_ro.ro_rt = NULL;
499 		}
500 	}
501 
502 	if (sc->sc_ro.ro_rt == NULL) {
503 		rtalloc(&sc->sc_ro);
504 		if (sc->sc_ro.ro_rt == NULL) {
505 			m_freem(m);
506 			return ENETUNREACH;
507 		}
508 	}
509 
510 #ifndef __OpenBSD__
511 	return ip_output(m, NULL, &sc->sc_ro, 0, NULL);
512 #else
513 	return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
514 #endif
515 }
516 
517 static int
518 stf_checkaddr4(sc, in, inifp)
519 	struct stf_softc *sc;
520 	struct in_addr *in;
521 	struct ifnet *inifp;	/* incoming interface */
522 {
523 	struct in_ifaddr *ia4;
524 
525 	/*
526 	 * reject packets with the following address:
527 	 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
528 	 */
529 	if (IN_MULTICAST(in->s_addr))
530 		return -1;
531 	switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
532 	case 0: case 127: case 255:
533 		return -1;
534 	}
535 
536 	/*
537 	 * reject packets with broadcast
538 	 */
539 #if defined(__OpenBSD__) || defined(__NetBSD__)
540 	for (ia4 = in_ifaddr.tqh_first; ia4; ia4 = ia4->ia_list.tqe_next)
541 #elif defined(__FreeBSD__) && __FreeBSD__ >= 3
542 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
543 	     ia4;
544 	     ia4 = TAILQ_NEXT(ia4, ia_link))
545 #else
546 	for (ia4 = in_ifaddr; ia4 != NULL; ia4 = ia4->ia_next)
547 #endif
548 	{
549 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
550 			continue;
551 		if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
552 			return -1;
553 	}
554 
555 	/*
556 	 * perform ingress filter
557 	 */
558 	if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
559 		struct sockaddr_in sin;
560 		struct rtentry *rt;
561 
562 		memset(&sin, 0, sizeof(sin));
563 		sin.sin_family = AF_INET;
564 		sin.sin_len = sizeof(struct sockaddr_in);
565 		sin.sin_addr = *in;
566 #ifdef __FreeBSD__
567 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
568 #else
569 		rt = rtalloc1((struct sockaddr *)&sin, 0);
570 #endif
571 		if (!rt || rt->rt_ifp != inifp) {
572 #if 0
573 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
574 			    "due to ingress filter\n", if_name(&sc->sc_if),
575 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
576 #endif
577 			if (rt)
578 				rtfree(rt);
579 			return -1;
580 		}
581 		rtfree(rt);
582 	}
583 
584 	return 0;
585 }
586 
587 static int
588 stf_checkaddr6(sc, in6, inifp)
589 	struct stf_softc *sc;
590 	struct in6_addr *in6;
591 	struct ifnet *inifp;	/* incoming interface */
592 {
593 	/*
594 	 * check 6to4 addresses
595 	 */
596 	if (IN6_IS_ADDR_6TO4(in6))
597 		return stf_checkaddr4(sc, GET_V4(in6), inifp);
598 
599 	/*
600 	 * reject anything that look suspicious.  the test is implemented
601 	 * in ip6_input too, but we check here as well to
602 	 * (1) reject bad packets earlier, and
603 	 * (2) to be safe against future ip6_input change.
604 	 */
605 	if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
606 		return -1;
607 
608 	return 0;
609 }
610 
611 void
612 #if __STDC__
613 in_stf_input(struct mbuf *m, ...)
614 #else
615 in_stf_input(m, va_alist)
616 	struct mbuf *m;
617 #endif
618 {
619 	int off, proto;
620 	struct stf_softc *sc;
621 	struct ip *ip;
622 	struct ip6_hdr *ip6;
623 	u_int8_t otos, itos;
624 	int s, isr;
625 	struct ifqueue *ifq = NULL;
626 	struct ifnet *ifp;
627 	va_list ap;
628 
629 	va_start(ap, m);
630 	off = va_arg(ap, int);
631 	proto = va_arg(ap, int);
632 	va_end(ap);
633 
634 	if (proto != IPPROTO_IPV6) {
635 		m_freem(m);
636 		return;
637 	}
638 
639 	ip = mtod(m, struct ip *);
640 
641 	sc = (struct stf_softc *)encap_getarg(m);
642 
643 	if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) {
644 		m_freem(m);
645 		return;
646 	}
647 
648 	ifp = &sc->sc_if;
649 
650 	/*
651 	 * perform sanity check against outer src/dst.
652 	 * for source, perform ingress filter as well.
653 	 */
654 	if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
655 	    stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
656 		m_freem(m);
657 		return;
658 	}
659 
660 	otos = ip->ip_tos;
661 	m_adj(m, off);
662 
663 	if (m->m_len < sizeof(*ip6)) {
664 		m = m_pullup(m, sizeof(*ip6));
665 		if (!m)
666 			return;
667 	}
668 	ip6 = mtod(m, struct ip6_hdr *);
669 
670 	/*
671 	 * perform sanity check against inner src/dst.
672 	 * for source, perform ingress filter as well.
673 	 */
674 	if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
675 	    stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
676 		m_freem(m);
677 		return;
678 	}
679 
680 	itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
681 	if ((ifp->if_flags & IFF_LINK1) != 0)
682 		ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
683 	else
684 		ip_ecn_egress(ECN_NOCARE, &otos, &itos);
685 	ip6->ip6_flow &= ~htonl(0xff << 20);
686 	ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
687 
688 	m->m_pkthdr.rcvif = ifp;
689 
690 #if NBPFILTER > 0
691 	if (ifp->if_bpf) {
692 		/*
693 		 * We need to prepend the address family as
694 		 * a four byte field.  Cons up a dummy header
695 		 * to pacify bpf.  This is safe because bpf
696 		 * will only read from the mbuf (i.e., it won't
697 		 * try to free it or keep a pointer a to it).
698 		 */
699 		struct mbuf m0;
700 		u_int32_t af = AF_INET6;
701 
702 		m0.m_next = m;
703 		m0.m_len = 4;
704 		m0.m_data = (char *)&af;
705 
706 #ifdef HAVE_OLD_BPF
707 		bpf_mtap(ifp, &m0);
708 #else
709 		bpf_mtap(ifp->if_bpf, &m0);
710 #endif
711 	}
712 #endif /*NBPFILTER > 0*/
713 
714 	/*
715 	 * Put the packet to the network layer input queue according to the
716 	 * specified address family.
717 	 * See net/if_gif.c for possible issues with packet processing
718 	 * reorder due to extra queueing.
719 	 */
720 	ifq = &ip6intrq;
721 	isr = NETISR_IPV6;
722 
723 	s = splnet();
724 	if (IF_QFULL(ifq)) {
725 		IF_DROP(ifq);	/* update statistics */
726 		m_freem(m);
727 		splx(s);
728 		return;
729 	}
730 	IF_ENQUEUE(ifq, m);
731 	schednetisr(isr);
732 	ifp->if_ipackets++;
733 	ifp->if_ibytes += m->m_pkthdr.len;
734 	splx(s);
735 }
736 
737 /* ARGSUSED */
738 static void
739 stf_rtrequest(cmd, rt, info)
740 	int cmd;
741 	struct rtentry *rt;
742 	struct rt_addrinfo *info;
743 {
744 
745 	if (rt)
746 		rt->rt_rmx.rmx_mtu = IPV6_MMTU;
747 }
748 
749 static int
750 stf_ioctl(ifp, cmd, data)
751 	struct ifnet *ifp;
752 #if defined(__FreeBSD__) && __FreeBSD__ < 3
753 	int cmd;
754 #else
755 	u_long cmd;
756 #endif
757 	caddr_t data;
758 {
759 	struct ifaddr *ifa;
760 	struct ifreq *ifr;
761 	struct sockaddr_in6 *sin6;
762 	int error;
763 
764 	error = 0;
765 	switch (cmd) {
766 	case SIOCSIFADDR:
767 		ifa = (struct ifaddr *)data;
768 		if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
769 			error = EAFNOSUPPORT;
770 			break;
771 		}
772 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
773 		if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) {
774 			ifa->ifa_rtrequest = stf_rtrequest;
775 			ifp->if_flags |= IFF_UP;
776 		} else
777 			error = EINVAL;
778 		break;
779 
780 	case SIOCADDMULTI:
781 	case SIOCDELMULTI:
782 		ifr = (struct ifreq *)data;
783 		if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
784 			;
785 		else
786 			error = EAFNOSUPPORT;
787 		break;
788 
789 	default:
790 		error = EINVAL;
791 		break;
792 	}
793 
794 	return error;
795 }
796 
797 #endif /* NSTF > 0 */
798