xref: /netbsd-src/sys/net/if_stf.c (revision 2c6fc41c810f5088457889d00eba558e8bc74d9e)
1 /*	$NetBSD: if_stf.c,v 1.78 2014/05/18 14:46:16 rmind 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 1.78 2014/05/18 14:46:16 rmind 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 
94 #include <sys/cpu.h>
95 
96 #include <net/if.h>
97 #include <net/route.h>
98 #include <net/netisr.h>
99 #include <net/if_types.h>
100 #include <net/if_stf.h>
101 
102 #include <netinet/in.h>
103 #include <netinet/in_systm.h>
104 #include <netinet/ip.h>
105 #include <netinet/ip_var.h>
106 #include <netinet/in_var.h>
107 
108 #include <netinet/ip6.h>
109 #include <netinet6/ip6_var.h>
110 #include <netinet6/in6_gif.h>
111 #include <netinet6/in6_var.h>
112 #include <netinet/ip_ecn.h>
113 
114 #include <netinet/ip_encap.h>
115 
116 #include <net/net_osdep.h>
117 
118 #include "stf.h"
119 #include "gif.h"	/*XXX*/
120 
121 #include <net/bpf.h>
122 
123 #if NGIF > 0
124 #include <net/if_gif.h>
125 #endif
126 
127 #define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
128 #define GET_V4(x)	((const struct in_addr *)(&(x)->s6_addr16[1]))
129 
130 struct stf_softc {
131 	struct ifnet	sc_if;	   /* common area */
132 	struct route	sc_ro;
133 	const struct encaptab *encap_cookie;
134 	LIST_ENTRY(stf_softc) sc_list;
135 };
136 
137 static LIST_HEAD(, stf_softc) stf_softc_list;
138 
139 static int	stf_clone_create(struct if_clone *, int);
140 static int	stf_clone_destroy(struct ifnet *);
141 
142 struct if_clone stf_cloner =
143     IF_CLONE_INITIALIZER("stf", stf_clone_create, stf_clone_destroy);
144 
145 #if NGIF > 0
146 extern int ip_gif_ttl;	/*XXX*/
147 #else
148 static int ip_gif_ttl = 40;	/*XXX*/
149 #endif
150 
151 extern struct domain inetdomain;
152 
153 static const struct protosw in_stf_protosw =
154 {
155 	.pr_type	= SOCK_RAW,
156 	.pr_domain	= &inetdomain,
157 	.pr_protocol	= IPPROTO_IPV6,
158 	.pr_flags	= PR_ATOMIC|PR_ADDR,
159 	.pr_input	= in_stf_input,
160 	.pr_output	= rip_output,
161 	.pr_ctlinput	= NULL,
162 	.pr_ctloutput	= rip_ctloutput,
163 	.pr_usrreqs	= &rip_usrreqs,
164 };
165 
166 void	stfattach(int);
167 
168 static int stf_encapcheck(struct mbuf *, int, int, void *);
169 static struct in6_ifaddr *stf_getsrcifa6(struct ifnet *);
170 static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
171 	struct rtentry *);
172 static int isrfc1918addr(const struct in_addr *);
173 static int stf_checkaddr4(struct stf_softc *, const struct in_addr *,
174 	struct ifnet *);
175 static int stf_checkaddr6(struct stf_softc *, const struct in6_addr *,
176 	struct ifnet *);
177 static void stf_rtrequest(int, struct rtentry *, const struct rt_addrinfo *);
178 static int stf_ioctl(struct ifnet *, u_long, void *);
179 
180 /* ARGSUSED */
181 void
182 stfattach(int count)
183 {
184 
185 	LIST_INIT(&stf_softc_list);
186 	if_clone_attach(&stf_cloner);
187 }
188 
189 static int
190 stf_clone_create(struct if_clone *ifc, int unit)
191 {
192 	struct stf_softc *sc;
193 
194 	if (LIST_FIRST(&stf_softc_list) != NULL) {
195 		/* Only one stf interface is allowed. */
196 		return (EEXIST);
197 	}
198 
199 	sc = malloc(sizeof(struct stf_softc), M_DEVBUF, M_WAIT|M_ZERO);
200 
201 	if_initname(&sc->sc_if, ifc->ifc_name, unit);
202 
203 	sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
204 	    stf_encapcheck, &in_stf_protosw, sc);
205 	if (sc->encap_cookie == NULL) {
206 		printf("%s: unable to attach encap\n", if_name(&sc->sc_if));
207 		free(sc, M_DEVBUF);
208 		return (EIO);	/* XXX */
209 	}
210 
211 	sc->sc_if.if_mtu    = STF_MTU;
212 	sc->sc_if.if_flags  = 0;
213 	sc->sc_if.if_ioctl  = stf_ioctl;
214 	sc->sc_if.if_output = stf_output;
215 	sc->sc_if.if_type   = IFT_STF;
216 	sc->sc_if.if_dlt    = DLT_NULL;
217 	if_attach(&sc->sc_if);
218 	if_alloc_sadl(&sc->sc_if);
219 	bpf_attach(&sc->sc_if, DLT_NULL, sizeof(u_int));
220 	LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
221 	return (0);
222 }
223 
224 static int
225 stf_clone_destroy(struct ifnet *ifp)
226 {
227 	struct stf_softc *sc = (void *) ifp;
228 
229 	LIST_REMOVE(sc, sc_list);
230 	encap_detach(sc->encap_cookie);
231 	bpf_detach(ifp);
232 	if_detach(ifp);
233 	rtcache_free(&sc->sc_ro);
234 	free(sc, M_DEVBUF);
235 
236 	return (0);
237 }
238 
239 static int
240 stf_encapcheck(struct mbuf *m, int off, int proto, void *arg)
241 {
242 	struct ip ip;
243 	struct in6_ifaddr *ia6;
244 	struct stf_softc *sc;
245 	struct in_addr a, b;
246 
247 	sc = (struct stf_softc *)arg;
248 	if (sc == NULL)
249 		return 0;
250 
251 	if ((sc->sc_if.if_flags & IFF_UP) == 0)
252 		return 0;
253 
254 	/* IFF_LINK0 means "no decapsulation" */
255 	if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
256 		return 0;
257 
258 	if (proto != IPPROTO_IPV6)
259 		return 0;
260 
261 	m_copydata(m, 0, sizeof(ip), (void *)&ip);
262 
263 	if (ip.ip_v != 4)
264 		return 0;
265 
266 	ia6 = stf_getsrcifa6(&sc->sc_if);
267 	if (ia6 == NULL)
268 		return 0;
269 
270 	/*
271 	 * check if IPv4 dst matches the IPv4 address derived from the
272 	 * local 6to4 address.
273 	 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
274 	 */
275 	if (memcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
276 	    sizeof(ip.ip_dst)) != 0)
277 		return 0;
278 
279 	/*
280 	 * check if IPv4 src matches the IPv4 address derived from the
281 	 * local 6to4 address masked by prefixmask.
282 	 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
283 	 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
284 	 */
285 	memset(&a, 0, sizeof(a));
286 	a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
287 	a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
288 	b = ip.ip_src;
289 	b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
290 	if (a.s_addr != b.s_addr)
291 		return 0;
292 
293 	/* stf interface makes single side match only */
294 	return 32;
295 }
296 
297 static struct in6_ifaddr *
298 stf_getsrcifa6(struct ifnet *ifp)
299 {
300 	struct ifaddr *ifa;
301 	struct in_ifaddr *ia4;
302 	struct sockaddr_in6 *sin6;
303 	struct in_addr in;
304 
305 	IFADDR_FOREACH(ifa, ifp)
306 	{
307 		if (ifa->ifa_addr == NULL)
308 			continue;
309 		if (ifa->ifa_addr->sa_family != AF_INET6)
310 			continue;
311 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
312 		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
313 			continue;
314 
315 		memcpy(&in, GET_V4(&sin6->sin6_addr), sizeof(in));
316 		INADDR_TO_IA(in, ia4);
317 		if (ia4 == NULL)
318 			continue;
319 
320 		return (struct in6_ifaddr *)ifa;
321 	}
322 
323 	return NULL;
324 }
325 
326 static int
327 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
328     struct rtentry *rt0)
329 {
330 	struct rtentry *rt;
331 	struct stf_softc *sc;
332 	const struct sockaddr_in6 *dst6;
333 	const struct in_addr *in4;
334 	uint8_t tos;
335 	struct ip *ip;
336 	struct ip6_hdr *ip6;
337 	struct in6_ifaddr *ia6;
338 	union {
339 		struct sockaddr		dst;
340 		struct sockaddr_in	dst4;
341 	} u;
342 
343 	sc = (struct stf_softc*)ifp;
344 	dst6 = (const struct sockaddr_in6 *)dst;
345 
346 	/* just in case */
347 	if ((ifp->if_flags & IFF_UP) == 0) {
348 		m_freem(m);
349 		return ENETDOWN;
350 	}
351 
352 	/*
353 	 * If we don't have an ip4 address that match my inner ip6 address,
354 	 * we shouldn't generate output.  Without this check, we'll end up
355 	 * using wrong IPv4 source.
356 	 */
357 	ia6 = stf_getsrcifa6(ifp);
358 	if (ia6 == NULL) {
359 		m_freem(m);
360 		ifp->if_oerrors++;
361 		return ENETDOWN;
362 	}
363 
364 	if (m->m_len < sizeof(*ip6)) {
365 		m = m_pullup(m, sizeof(*ip6));
366 		if (m == NULL) {
367 			ifp->if_oerrors++;
368 			return ENOBUFS;
369 		}
370 	}
371 	ip6 = mtod(m, struct ip6_hdr *);
372 	tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
373 
374 	/*
375 	 * Pickup the right outer dst addr from the list of candidates.
376 	 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
377 	 */
378 	if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
379 		in4 = GET_V4(&ip6->ip6_dst);
380 	else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
381 		in4 = GET_V4(&dst6->sin6_addr);
382 	else {
383 		m_freem(m);
384 		ifp->if_oerrors++;
385 		return ENETUNREACH;
386 	}
387 
388 	bpf_mtap_af(ifp, AF_INET6, m);
389 
390 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
391 	if (m && m->m_len < sizeof(struct ip))
392 		m = m_pullup(m, sizeof(struct ip));
393 	if (m == NULL) {
394 		ifp->if_oerrors++;
395 		return ENOBUFS;
396 	}
397 	ip = mtod(m, struct ip *);
398 
399 	memset(ip, 0, sizeof(*ip));
400 
401 	bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
402 	    &ip->ip_src, sizeof(ip->ip_src));
403 	memcpy(&ip->ip_dst, in4, sizeof(ip->ip_dst));
404 	ip->ip_p = IPPROTO_IPV6;
405 	ip->ip_ttl = ip_gif_ttl;	/*XXX*/
406 	ip->ip_len = htons(m->m_pkthdr.len);
407 	if (ifp->if_flags & IFF_LINK1)
408 		ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
409 	else
410 		ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
411 
412 	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
413 	if ((rt = rtcache_lookup(&sc->sc_ro, &u.dst)) == NULL) {
414 		m_freem(m);
415 		ifp->if_oerrors++;
416 		return ENETUNREACH;
417 	}
418 
419 	/* If the route constitutes infinite encapsulation, punt. */
420 	if (rt->rt_ifp == ifp) {
421 		rtcache_free(&sc->sc_ro);
422 		m_freem(m);
423 		ifp->if_oerrors++;
424 		return ENETUNREACH;
425 	}
426 
427 	ifp->if_opackets++;
428 	ifp->if_obytes += m->m_pkthdr.len - sizeof(struct ip);
429 	return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
430 }
431 
432 static int
433 isrfc1918addr(const struct in_addr *in)
434 {
435 	/*
436 	 * returns 1 if private address range:
437 	 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
438 	 */
439 	if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
440 	    (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
441 	    (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
442 		return 1;
443 
444 	return 0;
445 }
446 
447 static int
448 stf_checkaddr4(struct stf_softc *sc, const struct in_addr *in,
449     struct ifnet *inifp /*incoming interface*/)
450 {
451 	struct in_ifaddr *ia4;
452 
453 	/*
454 	 * reject packets with the following address:
455 	 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
456 	 */
457 	if (IN_MULTICAST(in->s_addr))
458 		return -1;
459 	switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
460 	case 0: case 127: case 255:
461 		return -1;
462 	}
463 
464 	/*
465 	 * reject packets with private address range.
466 	 * (requirement from RFC3056 section 2 1st paragraph)
467 	 */
468 	if (isrfc1918addr(in))
469 		return -1;
470 
471 	/*
472 	 * reject packet with IPv4 link-local (169.254.0.0/16),
473 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
474 	 */
475 	if (((ntohl(in->s_addr) & 0xff000000) >> 24) == 169 &&
476 	    ((ntohl(in->s_addr) & 0x00ff0000) >> 16) == 254)
477 		return -1;
478 
479 	/*
480 	 * reject packets with broadcast
481 	 */
482 	TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list)
483 	{
484 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
485 			continue;
486 		if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
487 			return -1;
488 	}
489 
490 	/*
491 	 * perform ingress filter
492 	 */
493 	if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
494 		struct sockaddr_in sin;
495 		struct rtentry *rt;
496 
497 		memset(&sin, 0, sizeof(sin));
498 		sin.sin_family = AF_INET;
499 		sin.sin_len = sizeof(struct sockaddr_in);
500 		sin.sin_addr = *in;
501 		rt = rtalloc1((struct sockaddr *)&sin, 0);
502 		if (!rt || rt->rt_ifp != inifp) {
503 #if 0
504 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
505 			    "due to ingress filter\n", if_name(&sc->sc_if),
506 			    (uint32_t)ntohl(sin.sin_addr.s_addr));
507 #endif
508 			if (rt)
509 				rtfree(rt);
510 			return -1;
511 		}
512 		rtfree(rt);
513 	}
514 
515 	return 0;
516 }
517 
518 static int
519 stf_checkaddr6(struct stf_softc *sc, const struct in6_addr *in6,
520     struct ifnet *inifp /*incoming interface*/)
521 {
522 
523 	/*
524 	 * check 6to4 addresses
525 	 */
526 	if (IN6_IS_ADDR_6TO4(in6))
527 		return stf_checkaddr4(sc, GET_V4(in6), inifp);
528 
529 	/*
530 	 * reject anything that look suspicious.  the test is implemented
531 	 * in ip6_input too, but we check here as well to
532 	 * (1) reject bad packets earlier, and
533 	 * (2) to be safe against future ip6_input change.
534 	 */
535 	if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
536 		return -1;
537 
538 	/*
539 	 * reject link-local and site-local unicast
540 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
541 	 */
542 	if (IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_SITELOCAL(in6))
543 		return -1;
544 
545 	/*
546 	 * reject node-local and link-local multicast
547 	 * as suggested in draft-savola-v6ops-6to4-security-00.txt
548 	 */
549 	if (IN6_IS_ADDR_MC_NODELOCAL(in6) || IN6_IS_ADDR_MC_LINKLOCAL(in6))
550 		return -1;
551 
552 	return 0;
553 }
554 
555 void
556 in_stf_input(struct mbuf *m, ...)
557 {
558 	int off, proto;
559 	struct stf_softc *sc;
560 	struct ip *ip;
561 	struct ip6_hdr *ip6;
562 	uint8_t otos, itos;
563 	int s, isr;
564 	struct ifqueue *ifq = NULL;
565 	struct ifnet *ifp;
566 	va_list ap;
567 
568 	va_start(ap, m);
569 	off = va_arg(ap, int);
570 	proto = va_arg(ap, int);
571 	va_end(ap);
572 
573 	if (proto != IPPROTO_IPV6) {
574 		m_freem(m);
575 		return;
576 	}
577 
578 	ip = mtod(m, struct ip *);
579 
580 	sc = (struct stf_softc *)encap_getarg(m);
581 
582 	if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) {
583 		m_freem(m);
584 		return;
585 	}
586 
587 	ifp = &sc->sc_if;
588 
589 	/*
590 	 * perform sanity check against outer src/dst.
591 	 * for source, perform ingress filter as well.
592 	 */
593 	if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
594 	    stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
595 		m_freem(m);
596 		return;
597 	}
598 
599 	otos = ip->ip_tos;
600 	m_adj(m, off);
601 
602 	if (m->m_len < sizeof(*ip6)) {
603 		m = m_pullup(m, sizeof(*ip6));
604 		if (!m)
605 			return;
606 	}
607 	ip6 = mtod(m, struct ip6_hdr *);
608 
609 	/*
610 	 * perform sanity check against inner src/dst.
611 	 * for source, perform ingress filter as well.
612 	 */
613 	if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
614 	    stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
615 		m_freem(m);
616 		return;
617 	}
618 
619 	itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
620 	if ((ifp->if_flags & IFF_LINK1) != 0)
621 		ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
622 	else
623 		ip_ecn_egress(ECN_NOCARE, &otos, &itos);
624 	ip6->ip6_flow &= ~htonl(0xff << 20);
625 	ip6->ip6_flow |= htonl((uint32_t)itos << 20);
626 
627 	m->m_pkthdr.rcvif = ifp;
628 
629 	bpf_mtap_af(ifp, AF_INET6, m);
630 
631 	/*
632 	 * Put the packet to the network layer input queue according to the
633 	 * specified address family.
634 	 * See net/if_gif.c for possible issues with packet processing
635 	 * reorder due to extra queueing.
636 	 */
637 	ifq = &ip6intrq;
638 	isr = NETISR_IPV6;
639 
640 	s = splnet();
641 	if (IF_QFULL(ifq)) {
642 		IF_DROP(ifq);	/* update statistics */
643 		m_freem(m);
644 		splx(s);
645 		return;
646 	}
647 	IF_ENQUEUE(ifq, m);
648 	schednetisr(isr);
649 	ifp->if_ipackets++;
650 	ifp->if_ibytes += m->m_pkthdr.len;
651 	splx(s);
652 }
653 
654 /* ARGSUSED */
655 static void
656 stf_rtrequest(int cmd, struct rtentry *rt,
657     const struct rt_addrinfo *info)
658 {
659 	if (rt != NULL) {
660 		struct stf_softc *sc;
661 
662 		sc = LIST_FIRST(&stf_softc_list);
663 		rt->rt_rmx.rmx_mtu = (sc != NULL) ? sc->sc_if.if_mtu : STF_MTU;
664 	}
665 }
666 
667 static int
668 stf_ioctl(struct ifnet *ifp, u_long cmd, void *data)
669 {
670 	struct ifaddr		*ifa;
671 	struct ifreq		*ifr = data;
672 	struct sockaddr_in6	*sin6;
673 	int			error;
674 
675 	error = 0;
676 	switch (cmd) {
677 	case SIOCINITIFADDR:
678 		ifa = (struct ifaddr *)data;
679 		if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
680 			error = EAFNOSUPPORT;
681 			break;
682 		}
683 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
684 		if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr) &&
685 		    !isrfc1918addr(GET_V4(&sin6->sin6_addr))) {
686 			ifa->ifa_rtrequest = stf_rtrequest;
687 			ifp->if_flags |= IFF_UP;
688 		} else
689 			error = EINVAL;
690 		break;
691 
692 	case SIOCADDMULTI:
693 	case SIOCDELMULTI:
694 		if (ifr != NULL &&
695 		    ifreq_getaddr(cmd, ifr)->sa_family == AF_INET6)
696 			;
697 		else
698 			error = EAFNOSUPPORT;
699 		break;
700 
701 	case SIOCSIFMTU:
702 		if (ifr->ifr_mtu < STF_MTU_MIN || ifr->ifr_mtu > STF_MTU_MAX)
703 			return EINVAL;
704 		else if ((error = ifioctl_common(ifp, cmd, data)) == ENETRESET)
705 			error = 0;
706 		break;
707 
708 	default:
709 		error = ifioctl_common(ifp, cmd, data);
710 		break;
711 	}
712 
713 	return error;
714 }
715