xref: /netbsd-src/sys/net/if_stf.c (revision aaf4ece63a859a04e37cf3a7229b5fab0157cc06)
1 /*	$NetBSD: if_stf.c,v 1.50 2005/12/11 23:05:25 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 #include <sys/cdefs.h>
78 __KERNEL_RCSID(0, "$NetBSD: if_stf.c,v 1.50 2005/12/11 23:05:25 thorpej Exp $");
79 
80 #include "opt_inet.h"
81 
82 #include <sys/param.h>
83 #include <sys/systm.h>
84 #include <sys/socket.h>
85 #include <sys/sockio.h>
86 #include <sys/mbuf.h>
87 #include <sys/errno.h>
88 #include <sys/ioctl.h>
89 #include <sys/proc.h>
90 #include <sys/protosw.h>
91 #include <sys/queue.h>
92 #include <sys/syslog.h>
93 #include <machine/cpu.h>
94 
95 #include <net/if.h>
96 #include <net/route.h>
97 #include <net/netisr.h>
98 #include <net/if_types.h>
99 #include <net/if_stf.h>
100 
101 #include <netinet/in.h>
102 #include <netinet/in_systm.h>
103 #include <netinet/ip.h>
104 #include <netinet/ip_var.h>
105 #include <netinet/in_var.h>
106 
107 #include <netinet/ip6.h>
108 #include <netinet6/ip6_var.h>
109 #include <netinet6/in6_gif.h>
110 #include <netinet6/in6_var.h>
111 #include <netinet/ip_ecn.h>
112 
113 #include <netinet/ip_encap.h>
114 
115 #include <machine/stdarg.h>
116 
117 #include <net/net_osdep.h>
118 
119 #include "bpfilter.h"
120 #include "stf.h"
121 #include "gif.h"	/*XXX*/
122 
123 #if NBPFILTER > 0
124 #include <net/bpf.h>
125 #endif
126 
127 #if NGIF > 0
128 #include <net/if_gif.h>
129 #endif
130 
131 #define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
132 #define GET_V4(x)	((struct in_addr *)(&(x)->s6_addr16[1]))
133 
134 struct stf_softc {
135 	struct ifnet	sc_if;	   /* common area */
136 	union {
137 		struct route  __sc_ro4;
138 		struct route_in6 __sc_ro6; /* just for safety */
139 	} __sc_ro46;
140 #define sc_ro	__sc_ro46.__sc_ro4
141 	const struct encaptab *encap_cookie;
142 	LIST_ENTRY(stf_softc) sc_list;
143 };
144 
145 static LIST_HEAD(, stf_softc) stf_softc_list;
146 
147 static int	stf_clone_create(struct if_clone *, int);
148 static int	stf_clone_destroy(struct ifnet *);
149 
150 struct if_clone stf_cloner =
151     IF_CLONE_INITIALIZER("stf", stf_clone_create, stf_clone_destroy);
152 
153 #if NGIF > 0
154 extern int ip_gif_ttl;	/*XXX*/
155 #else
156 static int ip_gif_ttl = 40;	/*XXX*/
157 #endif
158 
159 extern struct domain inetdomain;
160 static const struct protosw in_stf_protosw =
161 { SOCK_RAW,	&inetdomain,	IPPROTO_IPV6,	PR_ATOMIC|PR_ADDR,
162   in_stf_input, rip_output,	0,		rip_ctloutput,
163   rip_usrreq,
164   0,            0,              0,              0
165 };
166 
167 void	stfattach(int);
168 
169 static int stf_encapcheck(struct mbuf *, int, int, void *);
170 static struct in6_ifaddr *stf_getsrcifa6(struct ifnet *);
171 static int stf_output(struct ifnet *, struct mbuf *, struct sockaddr *,
172 	struct rtentry *);
173 static int isrfc1918addr(struct in_addr *);
174 static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
175 	struct ifnet *);
176 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
177 	struct ifnet *);
178 static void stf_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
179 static int stf_ioctl(struct ifnet *, u_long, caddr_t);
180 
181 /* ARGSUSED */
182 void
183 stfattach(int count)
184 {
185 
186 	LIST_INIT(&stf_softc_list);
187 	if_clone_attach(&stf_cloner);
188 }
189 
190 static int
191 stf_clone_create(struct if_clone *ifc, int unit)
192 {
193 	struct stf_softc *sc;
194 
195 	if (LIST_FIRST(&stf_softc_list) != NULL) {
196 		/* Only one stf interface is allowed. */
197 		return (EEXIST);
198 	}
199 
200 	sc = malloc(sizeof(struct stf_softc), M_DEVBUF, M_WAIT);
201 	memset(sc, 0, sizeof(struct stf_softc));
202 
203 	snprintf(sc->sc_if.if_xname, sizeof(sc->sc_if.if_xname), "%s%d",
204 	    ifc->ifc_name, unit);
205 
206 	sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
207 	    stf_encapcheck, &in_stf_protosw, sc);
208 	if (sc->encap_cookie == NULL) {
209 		printf("%s: unable to attach encap\n", if_name(&sc->sc_if));
210 		free(sc, M_DEVBUF);
211 		return (EIO);	/* XXX */
212 	}
213 
214 	sc->sc_if.if_mtu    = STF_MTU;
215 	sc->sc_if.if_flags  = 0;
216 	sc->sc_if.if_ioctl  = stf_ioctl;
217 	sc->sc_if.if_output = stf_output;
218 	sc->sc_if.if_type   = IFT_STF;
219 	sc->sc_if.if_dlt    = DLT_NULL;
220 	if_attach(&sc->sc_if);
221 	if_alloc_sadl(&sc->sc_if);
222 #if NBPFILTER > 0
223 	bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
224 #endif
225 	LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
226 	return (0);
227 }
228 
229 static int
230 stf_clone_destroy(struct ifnet *ifp)
231 {
232 	struct stf_softc *sc = (void *) ifp;
233 
234 	LIST_REMOVE(sc, sc_list);
235 	encap_detach(sc->encap_cookie);
236 #if NBPFILTER > 0
237 	bpfdetach(ifp);
238 #endif
239 	if_detach(ifp);
240 	free(sc, M_DEVBUF);
241 
242 	return (0);
243 }
244 
245 static int
246 stf_encapcheck(struct mbuf *m, int off, int proto, void *arg)
247 {
248 	struct ip ip;
249 	struct in6_ifaddr *ia6;
250 	struct stf_softc *sc;
251 	struct in_addr a, b;
252 
253 	sc = (struct stf_softc *)arg;
254 	if (sc == NULL)
255 		return 0;
256 
257 	if ((sc->sc_if.if_flags & IFF_UP) == 0)
258 		return 0;
259 
260 	/* IFF_LINK0 means "no decapsulation" */
261 	if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
262 		return 0;
263 
264 	if (proto != IPPROTO_IPV6)
265 		return 0;
266 
267 	m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
268 
269 	if (ip.ip_v != 4)
270 		return 0;
271 
272 	ia6 = stf_getsrcifa6(&sc->sc_if);
273 	if (ia6 == NULL)
274 		return 0;
275 
276 	/*
277 	 * check if IPv4 dst matches the IPv4 address derived from the
278 	 * local 6to4 address.
279 	 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
280 	 */
281 	if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
282 	    sizeof(ip.ip_dst)) != 0)
283 		return 0;
284 
285 	/*
286 	 * check if IPv4 src matches the IPv4 address derived from the
287 	 * local 6to4 address masked by prefixmask.
288 	 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
289 	 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
290 	 */
291 	memset(&a, 0, sizeof(a));
292 	a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
293 	a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
294 	b = ip.ip_src;
295 	b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
296 	if (a.s_addr != b.s_addr)
297 		return 0;
298 
299 	/* stf interface makes single side match only */
300 	return 32;
301 }
302 
303 static struct in6_ifaddr *
304 stf_getsrcifa6(struct ifnet *ifp)
305 {
306 	struct ifaddr *ifa;
307 	struct in_ifaddr *ia4;
308 	struct sockaddr_in6 *sin6;
309 	struct in_addr in;
310 
311 	IFADDR_FOREACH(ifa, ifp)
312 	{
313 		if (ifa->ifa_addr == NULL)
314 			continue;
315 		if (ifa->ifa_addr->sa_family != AF_INET6)
316 			continue;
317 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
318 		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
319 			continue;
320 
321 		bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
322 		INADDR_TO_IA(in, ia4);
323 		if (ia4 == NULL)
324 			continue;
325 
326 		return (struct in6_ifaddr *)ifa;
327 	}
328 
329 	return NULL;
330 }
331 
332 static int
333 stf_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
334     struct rtentry *rt)
335 {
336 	struct stf_softc *sc;
337 	struct sockaddr_in6 *dst6;
338 	struct in_addr *in4;
339 	struct sockaddr_in *dst4;
340 	u_int8_t tos;
341 	struct ip *ip;
342 	struct ip6_hdr *ip6;
343 	struct in6_ifaddr *ia6;
344 
345 	sc = (struct stf_softc*)ifp;
346 	dst6 = (struct sockaddr_in6 *)dst;
347 
348 	/* just in case */
349 	if ((ifp->if_flags & IFF_UP) == 0) {
350 		m_freem(m);
351 		return ENETDOWN;
352 	}
353 
354 	/*
355 	 * If we don't have an ip4 address that match my inner ip6 address,
356 	 * we shouldn't generate output.  Without this check, we'll end up
357 	 * using wrong IPv4 source.
358 	 */
359 	ia6 = stf_getsrcifa6(ifp);
360 	if (ia6 == NULL) {
361 		m_freem(m);
362 		ifp->if_oerrors++;
363 		return ENETDOWN;
364 	}
365 
366 	if (m->m_len < sizeof(*ip6)) {
367 		m = m_pullup(m, sizeof(*ip6));
368 		if (m == NULL) {
369 			ifp->if_oerrors++;
370 			return ENOBUFS;
371 		}
372 	}
373 	ip6 = mtod(m, struct ip6_hdr *);
374 	tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
375 
376 	/*
377 	 * Pickup the right outer dst addr from the list of candidates.
378 	 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
379 	 */
380 	if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
381 		in4 = GET_V4(&ip6->ip6_dst);
382 	else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
383 		in4 = GET_V4(&dst6->sin6_addr);
384 	else {
385 		m_freem(m);
386 		ifp->if_oerrors++;
387 		return ENETUNREACH;
388 	}
389 
390 #if NBPFILTER > 0
391 	if (ifp->if_bpf)
392 		bpf_mtap_af(ifp->if_bpf, AF_INET6, m);
393 #endif /*NBPFILTER > 0*/
394 
395 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
396 	if (m && m->m_len < sizeof(struct ip))
397 		m = m_pullup(m, sizeof(struct ip));
398 	if (m == NULL) {
399 		ifp->if_oerrors++;
400 		return ENOBUFS;
401 	}
402 	ip = mtod(m, struct ip *);
403 
404 	memset(ip, 0, sizeof(*ip));
405 
406 	bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
407 	    &ip->ip_src, sizeof(ip->ip_src));
408 	bcopy(in4, &ip->ip_dst, sizeof(ip->ip_dst));
409 	ip->ip_p = IPPROTO_IPV6;
410 	ip->ip_ttl = ip_gif_ttl;	/*XXX*/
411 	ip->ip_len = htons(m->m_pkthdr.len);
412 	if (ifp->if_flags & IFF_LINK1)
413 		ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
414 	else
415 		ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
416 
417 	dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
418 	if (dst4->sin_family != AF_INET ||
419 	    bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
420 		/* cache route doesn't match */
421 		dst4->sin_family = AF_INET;
422 		dst4->sin_len = sizeof(struct sockaddr_in);
423 		bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
424 		if (sc->sc_ro.ro_rt) {
425 			RTFREE(sc->sc_ro.ro_rt);
426 			sc->sc_ro.ro_rt = NULL;
427 		}
428 	}
429 
430 	if (sc->sc_ro.ro_rt == NULL) {
431 		rtalloc(&sc->sc_ro);
432 		if (sc->sc_ro.ro_rt == NULL) {
433 			m_freem(m);
434 			ifp->if_oerrors++;
435 			return ENETUNREACH;
436 		}
437 	}
438 
439 	ifp->if_opackets++;
440 	return ip_output(m, NULL, &sc->sc_ro, 0,
441 	    (struct ip_moptions *)NULL, (struct socket *)NULL);
442 }
443 
444 static int
445 isrfc1918addr(struct in_addr *in)
446 {
447 	/*
448 	 * returns 1 if private address range:
449 	 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
450 	 */
451 	if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
452 	    (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
453 	    (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
454 		return 1;
455 
456 	return 0;
457 }
458 
459 static int
460 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in,
461     struct ifnet *inifp /*incoming interface*/)
462 {
463 	struct in_ifaddr *ia4;
464 
465 	/*
466 	 * reject packets with the following address:
467 	 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
468 	 */
469 	if (IN_MULTICAST(in->s_addr))
470 		return -1;
471 	switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
472 	case 0: case 127: case 255:
473 		return -1;
474 	}
475 
476 	/*
477 	 * reject packets with private address range.
478 	 * (requirement from RFC3056 section 2 1st paragraph)
479 	 */
480 	if (isrfc1918addr(in))
481 		return -1;
482 
483 	/*
484 	 * reject packet with IPv4 link-local (169.254.0.0/16),
485 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
486 	 */
487 	if (((ntohl(in->s_addr) & 0xff000000) >> 24) == 169 &&
488 	    ((ntohl(in->s_addr) & 0x00ff0000) >> 16) == 254)
489 		return -1;
490 
491 	/*
492 	 * reject packets with broadcast
493 	 */
494 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list)
495 	{
496 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
497 			continue;
498 		if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
499 			return -1;
500 	}
501 
502 	/*
503 	 * perform ingress filter
504 	 */
505 	if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
506 		struct sockaddr_in sin;
507 		struct rtentry *rt;
508 
509 		memset(&sin, 0, sizeof(sin));
510 		sin.sin_family = AF_INET;
511 		sin.sin_len = sizeof(struct sockaddr_in);
512 		sin.sin_addr = *in;
513 		rt = rtalloc1((struct sockaddr *)&sin, 0);
514 		if (!rt || rt->rt_ifp != inifp) {
515 #if 0
516 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
517 			    "due to ingress filter\n", if_name(&sc->sc_if),
518 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
519 #endif
520 			if (rt)
521 				rtfree(rt);
522 			return -1;
523 		}
524 		rtfree(rt);
525 	}
526 
527 	return 0;
528 }
529 
530 static int
531 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6,
532     struct ifnet *inifp /*incoming interface*/)
533 {
534 
535 	/*
536 	 * check 6to4 addresses
537 	 */
538 	if (IN6_IS_ADDR_6TO4(in6))
539 		return stf_checkaddr4(sc, GET_V4(in6), inifp);
540 
541 	/*
542 	 * reject anything that look suspicious.  the test is implemented
543 	 * in ip6_input too, but we check here as well to
544 	 * (1) reject bad packets earlier, and
545 	 * (2) to be safe against future ip6_input change.
546 	 */
547 	if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
548 		return -1;
549 
550 	/*
551 	 * reject link-local and site-local unicast
552 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
553 	 */
554 	if (IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_SITELOCAL(in6))
555 		return -1;
556 
557 	/*
558 	 * reject node-local and link-local multicast
559 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
560 	 */
561 	if (IN6_IS_ADDR_MC_NODELOCAL(in6) || IN6_IS_ADDR_MC_LINKLOCAL(in6))
562 		return -1;
563 
564 	return 0;
565 }
566 
567 void
568 in_stf_input(struct mbuf *m, ...)
569 {
570 	int off, proto;
571 	struct stf_softc *sc;
572 	struct ip *ip;
573 	struct ip6_hdr *ip6;
574 	u_int8_t otos, itos;
575 	int s, isr;
576 	struct ifqueue *ifq = NULL;
577 	struct ifnet *ifp;
578 	va_list ap;
579 
580 	va_start(ap, m);
581 	off = va_arg(ap, int);
582 	proto = va_arg(ap, int);
583 	va_end(ap);
584 
585 	if (proto != IPPROTO_IPV6) {
586 		m_freem(m);
587 		return;
588 	}
589 
590 	ip = mtod(m, struct ip *);
591 
592 	sc = (struct stf_softc *)encap_getarg(m);
593 
594 	if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) {
595 		m_freem(m);
596 		return;
597 	}
598 
599 	ifp = &sc->sc_if;
600 
601 	/*
602 	 * perform sanity check against outer src/dst.
603 	 * for source, perform ingress filter as well.
604 	 */
605 	if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
606 	    stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
607 		m_freem(m);
608 		return;
609 	}
610 
611 	otos = ip->ip_tos;
612 	m_adj(m, off);
613 
614 	if (m->m_len < sizeof(*ip6)) {
615 		m = m_pullup(m, sizeof(*ip6));
616 		if (!m)
617 			return;
618 	}
619 	ip6 = mtod(m, struct ip6_hdr *);
620 
621 	/*
622 	 * perform sanity check against inner src/dst.
623 	 * for source, perform ingress filter as well.
624 	 */
625 	if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
626 	    stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
627 		m_freem(m);
628 		return;
629 	}
630 
631 	itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
632 	if ((ifp->if_flags & IFF_LINK1) != 0)
633 		ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
634 	else
635 		ip_ecn_egress(ECN_NOCARE, &otos, &itos);
636 	ip6->ip6_flow &= ~htonl(0xff << 20);
637 	ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
638 
639 	m->m_pkthdr.rcvif = ifp;
640 
641 #if NBPFILTER > 0
642 	if (ifp->if_bpf)
643 		bpf_mtap_af(ifp->if_bpf, AF_INET6, m);
644 #endif /*NBPFILTER > 0*/
645 
646 	/*
647 	 * Put the packet to the network layer input queue according to the
648 	 * specified address family.
649 	 * See net/if_gif.c for possible issues with packet processing
650 	 * reorder due to extra queueing.
651 	 */
652 	ifq = &ip6intrq;
653 	isr = NETISR_IPV6;
654 
655 	s = splnet();
656 	if (IF_QFULL(ifq)) {
657 		IF_DROP(ifq);	/* update statistics */
658 		m_freem(m);
659 		splx(s);
660 		return;
661 	}
662 	IF_ENQUEUE(ifq, m);
663 	schednetisr(isr);
664 	ifp->if_ipackets++;
665 	ifp->if_ibytes += m->m_pkthdr.len;
666 	splx(s);
667 }
668 
669 /* ARGSUSED */
670 static void
671 stf_rtrequest(int cmd, struct rtentry *rt, struct rt_addrinfo *info)
672 {
673 	if (rt != NULL) {
674 		struct stf_softc *sc;
675 
676 		sc = LIST_FIRST(&stf_softc_list);
677 		rt->rt_rmx.rmx_mtu = (sc != NULL) ? sc->sc_if.if_mtu : STF_MTU;
678 	}
679 }
680 
681 static int
682 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
683 {
684 	struct proc 		*p = curproc;	/* XXX */
685 	struct ifaddr		*ifa;
686 	struct ifreq		*ifr;
687 	struct sockaddr_in6	*sin6;
688 	int			error;
689 	u_long			mtu;
690 
691 	error = 0;
692 	switch (cmd) {
693 	case SIOCSIFADDR:
694 		ifa = (struct ifaddr *)data;
695 		if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
696 			error = EAFNOSUPPORT;
697 			break;
698 		}
699 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
700 		if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr) &&
701 		    !isrfc1918addr(GET_V4(&sin6->sin6_addr))) {
702 			ifa->ifa_rtrequest = stf_rtrequest;
703 			ifp->if_flags |= IFF_UP;
704 		} else
705 			error = EINVAL;
706 		break;
707 
708 	case SIOCADDMULTI:
709 	case SIOCDELMULTI:
710 		ifr = (struct ifreq *)data;
711 		if (ifr != NULL && ifr->ifr_addr.sa_family == AF_INET6)
712 			;
713 		else
714 			error = EAFNOSUPPORT;
715 		break;
716 
717 	case SIOCSIFMTU:
718 		if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
719 			break;
720 		ifr = (struct ifreq *)data;
721 		mtu = ifr->ifr_mtu;
722 		if (mtu < STF_MTU_MIN || mtu > STF_MTU_MAX)
723 			return EINVAL;
724 		ifp->if_mtu = mtu;
725 		break;
726 
727 	default:
728 		error = EINVAL;
729 		break;
730 	}
731 
732 	return error;
733 }
734