xref: /freebsd/sys/net/if_stf.c (revision 3642298923e528d795e3a30ec165d2b469e28b40) 
1 /*	$FreeBSD$	*/
2 /*	$KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi 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 "opt_inet.h"
78 #include "opt_inet6.h"
79 #include "opt_mac.h"
80 
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/socket.h>
84 #include <sys/sockio.h>
85 #include <sys/mac.h>
86 #include <sys/mbuf.h>
87 #include <sys/errno.h>
88 #include <sys/kernel.h>
89 #include <sys/module.h>
90 #include <sys/protosw.h>
91 #include <sys/queue.h>
92 #include <machine/cpu.h>
93 
94 #include <sys/malloc.h>
95 
96 #include <net/if.h>
97 #include <net/if_clone.h>
98 #include <net/route.h>
99 #include <net/netisr.h>
100 #include <net/if_types.h>
101 #include <net/if_stf.h>
102 
103 #include <netinet/in.h>
104 #include <netinet/in_systm.h>
105 #include <netinet/ip.h>
106 #include <netinet/ip_var.h>
107 #include <netinet/in_var.h>
108 
109 #include <netinet/ip6.h>
110 #include <netinet6/ip6_var.h>
111 #include <netinet6/in6_var.h>
112 #include <netinet/ip_ecn.h>
113 
114 #include <netinet/ip_encap.h>
115 
116 #include <machine/stdarg.h>
117 
118 #include <net/net_osdep.h>
119 
120 #include <net/bpf.h>
121 
122 #define STFNAME		"stf"
123 #define STFUNIT		0
124 
125 #define IN6_IS_ADDR_6TO4(x)	(ntohs((x)->s6_addr16[0]) == 0x2002)
126 
127 /*
128  * XXX: Return a pointer with 16-bit aligned.  Don't cast it to
129  * struct in_addr *; use bcopy() instead.
130  */
131 #define GET_V4(x)	((caddr_t)(&(x)->s6_addr16[1]))
132 
133 struct stf_softc {
134 	struct ifnet	*sc_ifp;
135 	union {
136 		struct route  __sc_ro4;
137 		struct route_in6 __sc_ro6; /* just for safety */
138 	} __sc_ro46;
139 #define sc_ro	__sc_ro46.__sc_ro4
140 	const struct encaptab *encap_cookie;
141 	LIST_ENTRY(stf_softc) sc_list;	/* all stf's are linked */
142 };
143 #define STF2IFP(sc)	((sc)->sc_ifp)
144 
145 /*
146  * All mutable global variables in if_stf.c are protected by stf_mtx.
147  * XXXRW: Note that mutable fields in the softc are not currently locked:
148  * in particular, sc_ro needs to be protected from concurrent entrance
149  * of stf_output().
150  */
151 static struct mtx stf_mtx;
152 static LIST_HEAD(, stf_softc) stf_softc_list;
153 
154 static MALLOC_DEFINE(M_STF, STFNAME, "6to4 Tunnel Interface");
155 static const int ip_stf_ttl = 40;
156 
157 extern  struct domain inetdomain;
158 struct protosw in_stf_protosw =
159 { SOCK_RAW,	&inetdomain,	IPPROTO_IPV6,	PR_ATOMIC|PR_ADDR,
160   in_stf_input,	(pr_output_t*)rip_output, 0,	rip_ctloutput,
161   0,
162   0,            0,              0,              0,
163   &rip_usrreqs
164 };
165 
166 static char *stfnames[] = {"stf0", "stf", "6to4", NULL};
167 
168 static int stfmodevent(module_t, int, void *);
169 static int stf_encapcheck(const 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 static int stf_clone_match(struct if_clone *, const char *);
182 static int stf_clone_create(struct if_clone *, char *, size_t);
183 static int stf_clone_destroy(struct if_clone *, struct ifnet *);
184 struct if_clone stf_cloner = IFC_CLONE_INITIALIZER(STFNAME, NULL, 0,
185     NULL, stf_clone_match, stf_clone_create, stf_clone_destroy);
186 
187 static int
188 stf_clone_match(struct if_clone *ifc, const char *name)
189 {
190 	int i;
191 
192 	for(i = 0; stfnames[i] != NULL; i++) {
193 		if (strcmp(stfnames[i], name) == 0)
194 			return (1);
195 	}
196 
197 	return (0);
198 }
199 
200 static int
201 stf_clone_create(struct if_clone *ifc, char *name, size_t len)
202 {
203 	int err, unit;
204 	struct stf_softc *sc;
205 	struct ifnet *ifp;
206 
207 	/*
208 	 * We can only have one unit, but since unit allocation is
209 	 * already locked, we use it to keep from allocating extra
210 	 * interfaces.
211 	 */
212 	unit = STFUNIT;
213 	err = ifc_alloc_unit(ifc, &unit);
214 	if (err != 0)
215 		return (err);
216 
217 	sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
218 	ifp = STF2IFP(sc) = if_alloc(IFT_STF);
219 	if (ifp == NULL) {
220 		free(sc, M_STF);
221 		ifc_free_unit(ifc, unit);
222 		return (ENOSPC);
223 	}
224 	ifp->if_softc = sc;
225 
226 	/*
227 	 * Set the name manually rather then using if_initname because
228 	 * we don't conform to the default naming convention for interfaces.
229 	 */
230 	strlcpy(ifp->if_xname, name, IFNAMSIZ);
231 	ifp->if_dname = ifc->ifc_name;
232 	ifp->if_dunit = IF_DUNIT_NONE;
233 
234 	sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
235 	    stf_encapcheck, &in_stf_protosw, sc);
236 	if (sc->encap_cookie == NULL) {
237 		if_printf(ifp, "attach failed\n");
238 		free(sc, M_STF);
239 		ifc_free_unit(ifc, unit);
240 		return (ENOMEM);
241 	}
242 
243 	ifp->if_mtu    = IPV6_MMTU;
244 	ifp->if_ioctl  = stf_ioctl;
245 	ifp->if_output = stf_output;
246 	ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
247 	if_attach(ifp);
248 	bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
249 	mtx_lock(&stf_mtx);
250 	LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
251 	mtx_unlock(&stf_mtx);
252 	return (0);
253 }
254 
255 static void
256 stf_destroy(struct stf_softc *sc)
257 {
258 	int err;
259 
260 	err = encap_detach(sc->encap_cookie);
261 	KASSERT(err == 0, ("Unexpected error detaching encap_cookie"));
262 	bpfdetach(STF2IFP(sc));
263 	if_detach(STF2IFP(sc));
264 	if_free(STF2IFP(sc));
265 
266 	free(sc, M_STF);
267 }
268 
269 static int
270 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp)
271 {
272 	struct stf_softc *sc = ifp->if_softc;
273 
274 	mtx_lock(&stf_mtx);
275 	LIST_REMOVE(sc, sc_list);
276 	mtx_unlock(&stf_mtx);
277 
278 	stf_destroy(sc);
279 	ifc_free_unit(ifc, STFUNIT);
280 
281 	return (0);
282 }
283 
284 static int
285 stfmodevent(mod, type, data)
286 	module_t mod;
287 	int type;
288 	void *data;
289 {
290 	struct stf_softc *sc;
291 
292 	switch (type) {
293 	case MOD_LOAD:
294 		mtx_init(&stf_mtx, "stf_mtx", NULL, MTX_DEF);
295 		LIST_INIT(&stf_softc_list);
296 		if_clone_attach(&stf_cloner);
297 
298 		break;
299 	case MOD_UNLOAD:
300 		if_clone_detach(&stf_cloner);
301 
302 		mtx_lock(&stf_mtx);
303 		while ((sc = LIST_FIRST(&stf_softc_list)) != NULL) {
304 			LIST_REMOVE(sc, sc_list);
305 			mtx_unlock(&stf_mtx);
306 			stf_destroy(sc);
307 			mtx_lock(&stf_mtx);
308 		}
309 		mtx_unlock(&stf_mtx);
310 		mtx_destroy(&stf_mtx);
311 		break;
312 	default:
313 		return (EOPNOTSUPP);
314 	}
315 
316 	return (0);
317 }
318 
319 static moduledata_t stf_mod = {
320 	"if_stf",
321 	stfmodevent,
322 	0
323 };
324 
325 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
326 
327 static int
328 stf_encapcheck(m, off, proto, arg)
329 	const struct mbuf *m;
330 	int off;
331 	int proto;
332 	void *arg;
333 {
334 	struct ip ip;
335 	struct in6_ifaddr *ia6;
336 	struct stf_softc *sc;
337 	struct in_addr a, b, mask;
338 
339 	sc = (struct stf_softc *)arg;
340 	if (sc == NULL)
341 		return 0;
342 
343 	if ((STF2IFP(sc)->if_flags & IFF_UP) == 0)
344 		return 0;
345 
346 	/* IFF_LINK0 means "no decapsulation" */
347 	if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0)
348 		return 0;
349 
350 	if (proto != IPPROTO_IPV6)
351 		return 0;
352 
353 	/* LINTED const cast */
354 	m_copydata((struct mbuf *)(uintptr_t)m, 0, sizeof(ip), (caddr_t)&ip);
355 
356 	if (ip.ip_v != 4)
357 		return 0;
358 
359 	ia6 = stf_getsrcifa6(STF2IFP(sc));
360 	if (ia6 == NULL)
361 		return 0;
362 
363 	/*
364 	 * check if IPv4 dst matches the IPv4 address derived from the
365 	 * local 6to4 address.
366 	 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
367 	 */
368 	if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
369 	    sizeof(ip.ip_dst)) != 0)
370 		return 0;
371 
372 	/*
373 	 * check if IPv4 src matches the IPv4 address derived from the
374 	 * local 6to4 address masked by prefixmask.
375 	 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
376 	 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
377 	 */
378 	bzero(&a, sizeof(a));
379 	bcopy(GET_V4(&ia6->ia_addr.sin6_addr), &a, sizeof(a));
380 	bcopy(GET_V4(&ia6->ia_prefixmask.sin6_addr), &mask, sizeof(mask));
381 	a.s_addr &= mask.s_addr;
382 	b = ip.ip_src;
383 	b.s_addr &= mask.s_addr;
384 	if (a.s_addr != b.s_addr)
385 		return 0;
386 
387 	/* stf interface makes single side match only */
388 	return 32;
389 }
390 
391 static struct in6_ifaddr *
392 stf_getsrcifa6(ifp)
393 	struct ifnet *ifp;
394 {
395 	struct ifaddr *ia;
396 	struct in_ifaddr *ia4;
397 	struct sockaddr_in6 *sin6;
398 	struct in_addr in;
399 
400 	for (ia = TAILQ_FIRST(&ifp->if_addrlist);
401 	     ia;
402 	     ia = TAILQ_NEXT(ia, ifa_list))
403 	{
404 		if (ia->ifa_addr == NULL)
405 			continue;
406 		if (ia->ifa_addr->sa_family != AF_INET6)
407 			continue;
408 		sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
409 		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
410 			continue;
411 
412 		bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
413 		LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
414 			if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
415 				break;
416 		if (ia4 == NULL)
417 			continue;
418 
419 		return (struct in6_ifaddr *)ia;
420 	}
421 
422 	return NULL;
423 }
424 
425 static int
426 stf_output(ifp, m, dst, rt)
427 	struct ifnet *ifp;
428 	struct mbuf *m;
429 	struct sockaddr *dst;
430 	struct rtentry *rt;
431 {
432 	struct stf_softc *sc;
433 	struct sockaddr_in6 *dst6;
434 	struct in_addr in4;
435 	caddr_t ptr;
436 	struct sockaddr_in *dst4;
437 	u_int8_t tos;
438 	struct ip *ip;
439 	struct ip6_hdr *ip6;
440 	struct in6_ifaddr *ia6;
441 	u_int32_t af;
442 #ifdef MAC
443 	int error;
444 
445 	error = mac_check_ifnet_transmit(ifp, m);
446 	if (error) {
447 		m_freem(m);
448 		return (error);
449 	}
450 #endif
451 
452 	sc = ifp->if_softc;
453 	dst6 = (struct sockaddr_in6 *)dst;
454 
455 	/* just in case */
456 	if ((ifp->if_flags & IFF_UP) == 0) {
457 		m_freem(m);
458 		ifp->if_oerrors++;
459 		return ENETDOWN;
460 	}
461 
462 	/*
463 	 * If we don't have an ip4 address that match my inner ip6 address,
464 	 * we shouldn't generate output.  Without this check, we'll end up
465 	 * using wrong IPv4 source.
466 	 */
467 	ia6 = stf_getsrcifa6(ifp);
468 	if (ia6 == NULL) {
469 		m_freem(m);
470 		ifp->if_oerrors++;
471 		return ENETDOWN;
472 	}
473 
474 	if (m->m_len < sizeof(*ip6)) {
475 		m = m_pullup(m, sizeof(*ip6));
476 		if (!m) {
477 			ifp->if_oerrors++;
478 			return ENOBUFS;
479 		}
480 	}
481 	ip6 = mtod(m, struct ip6_hdr *);
482 	tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
483 
484 	/*
485 	 * BPF writes need to be handled specially.
486 	 * This is a null operation, nothing here checks dst->sa_family.
487 	 */
488 	if (dst->sa_family == AF_UNSPEC) {
489 		bcopy(dst->sa_data, &af, sizeof(af));
490 		dst->sa_family = af;
491 	}
492 
493 	/*
494 	 * Pickup the right outer dst addr from the list of candidates.
495 	 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
496 	 */
497 	ptr = NULL;
498 	if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
499 		ptr = GET_V4(&ip6->ip6_dst);
500 	else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
501 		ptr = GET_V4(&dst6->sin6_addr);
502 	else {
503 		m_freem(m);
504 		ifp->if_oerrors++;
505 		return ENETUNREACH;
506 	}
507 	bcopy(ptr, &in4, sizeof(in4));
508 
509 	if (ifp->if_bpf) {
510 		/*
511 		 * We need to prepend the address family as
512 		 * a four byte field.  Cons up a dummy header
513 		 * to pacify bpf.  This is safe because bpf
514 		 * will only read from the mbuf (i.e., it won't
515 		 * try to free it or keep a pointer a to it).
516 		 */
517 		af = AF_INET6;
518 		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
519 	}
520 
521 	M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
522 	if (m && m->m_len < sizeof(struct ip))
523 		m = m_pullup(m, sizeof(struct ip));
524 	if (m == NULL) {
525 		ifp->if_oerrors++;
526 		return ENOBUFS;
527 	}
528 	ip = mtod(m, struct ip *);
529 
530 	bzero(ip, sizeof(*ip));
531 
532 	bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
533 	    &ip->ip_src, sizeof(ip->ip_src));
534 	bcopy(&in4, &ip->ip_dst, sizeof(ip->ip_dst));
535 	ip->ip_p = IPPROTO_IPV6;
536 	ip->ip_ttl = ip_stf_ttl;
537 	ip->ip_len = m->m_pkthdr.len;	/*host order*/
538 	if (ifp->if_flags & IFF_LINK1)
539 		ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
540 	else
541 		ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
542 
543 	/*
544 	 * XXXRW: Locking of sc_ro required.
545 	 */
546 	dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
547 	if (dst4->sin_family != AF_INET ||
548 	    bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
549 		/* cache route doesn't match */
550 		dst4->sin_family = AF_INET;
551 		dst4->sin_len = sizeof(struct sockaddr_in);
552 		bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
553 		if (sc->sc_ro.ro_rt) {
554 			RTFREE(sc->sc_ro.ro_rt);
555 			sc->sc_ro.ro_rt = NULL;
556 		}
557 	}
558 
559 	if (sc->sc_ro.ro_rt == NULL) {
560 		rtalloc(&sc->sc_ro);
561 		if (sc->sc_ro.ro_rt == NULL) {
562 			m_freem(m);
563 			ifp->if_oerrors++;
564 			return ENETUNREACH;
565 		}
566 	}
567 
568 	ifp->if_opackets++;
569 	return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
570 }
571 
572 static int
573 isrfc1918addr(in)
574 	struct in_addr *in;
575 {
576 	/*
577 	 * returns 1 if private address range:
578 	 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
579 	 */
580 	if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
581 	    (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
582 	    (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
583 		return 1;
584 
585 	return 0;
586 }
587 
588 static int
589 stf_checkaddr4(sc, in, inifp)
590 	struct stf_softc *sc;
591 	struct in_addr *in;
592 	struct ifnet *inifp;	/* incoming interface */
593 {
594 	struct in_ifaddr *ia4;
595 
596 	/*
597 	 * reject packets with the following address:
598 	 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
599 	 */
600 	if (IN_MULTICAST(ntohl(in->s_addr)))
601 		return -1;
602 	switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
603 	case 0: case 127: case 255:
604 		return -1;
605 	}
606 
607 	/*
608 	 * reject packets with private address range.
609 	 * (requirement from RFC3056 section 2 1st paragraph)
610 	 */
611 	if (isrfc1918addr(in))
612 		return -1;
613 
614 	/*
615 	 * reject packets with broadcast
616 	 */
617 	for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
618 	     ia4;
619 	     ia4 = TAILQ_NEXT(ia4, ia_link))
620 	{
621 		if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
622 			continue;
623 		if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
624 			return -1;
625 	}
626 
627 	/*
628 	 * perform ingress filter
629 	 */
630 	if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) {
631 		struct sockaddr_in sin;
632 		struct rtentry *rt;
633 
634 		bzero(&sin, sizeof(sin));
635 		sin.sin_family = AF_INET;
636 		sin.sin_len = sizeof(struct sockaddr_in);
637 		sin.sin_addr = *in;
638 		rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
639 		if (!rt || rt->rt_ifp != inifp) {
640 #if 0
641 			log(LOG_WARNING, "%s: packet from 0x%x dropped "
642 			    "due to ingress filter\n", if_name(STF2IFP(sc)),
643 			    (u_int32_t)ntohl(sin.sin_addr.s_addr));
644 #endif
645 			if (rt)
646 				rtfree(rt);
647 			return -1;
648 		}
649 		rtfree(rt);
650 	}
651 
652 	return 0;
653 }
654 
655 static int
656 stf_checkaddr6(sc, in6, inifp)
657 	struct stf_softc *sc;
658 	struct in6_addr *in6;
659 	struct ifnet *inifp;	/* incoming interface */
660 {
661 	/*
662 	 * check 6to4 addresses
663 	 */
664 	if (IN6_IS_ADDR_6TO4(in6)) {
665 		struct in_addr in4;
666 		bcopy(GET_V4(in6), &in4, sizeof(in4));
667 		return stf_checkaddr4(sc, &in4, inifp);
668 	}
669 
670 	/*
671 	 * reject anything that look suspicious.  the test is implemented
672 	 * in ip6_input too, but we check here as well to
673 	 * (1) reject bad packets earlier, and
674 	 * (2) to be safe against future ip6_input change.
675 	 */
676 	if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
677 		return -1;
678 
679 	return 0;
680 }
681 
682 void
683 in_stf_input(m, off)
684 	struct mbuf *m;
685 	int off;
686 {
687 	int proto;
688 	struct stf_softc *sc;
689 	struct ip *ip;
690 	struct ip6_hdr *ip6;
691 	u_int8_t otos, itos;
692 	struct ifnet *ifp;
693 
694 	proto = mtod(m, struct ip *)->ip_p;
695 
696 	if (proto != IPPROTO_IPV6) {
697 		m_freem(m);
698 		return;
699 	}
700 
701 	ip = mtod(m, struct ip *);
702 
703 	sc = (struct stf_softc *)encap_getarg(m);
704 
705 	if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) {
706 		m_freem(m);
707 		return;
708 	}
709 
710 	ifp = STF2IFP(sc);
711 
712 #ifdef MAC
713 	mac_create_mbuf_from_ifnet(ifp, m);
714 #endif
715 
716 	/*
717 	 * perform sanity check against outer src/dst.
718 	 * for source, perform ingress filter as well.
719 	 */
720 	if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
721 	    stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
722 		m_freem(m);
723 		return;
724 	}
725 
726 	otos = ip->ip_tos;
727 	m_adj(m, off);
728 
729 	if (m->m_len < sizeof(*ip6)) {
730 		m = m_pullup(m, sizeof(*ip6));
731 		if (!m)
732 			return;
733 	}
734 	ip6 = mtod(m, struct ip6_hdr *);
735 
736 	/*
737 	 * perform sanity check against inner src/dst.
738 	 * for source, perform ingress filter as well.
739 	 */
740 	if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
741 	    stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
742 		m_freem(m);
743 		return;
744 	}
745 
746 	itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
747 	if ((ifp->if_flags & IFF_LINK1) != 0)
748 		ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
749 	else
750 		ip_ecn_egress(ECN_NOCARE, &otos, &itos);
751 	ip6->ip6_flow &= ~htonl(0xff << 20);
752 	ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
753 
754 	m->m_pkthdr.rcvif = ifp;
755 
756 	if (ifp->if_bpf) {
757 		/*
758 		 * We need to prepend the address family as
759 		 * a four byte field.  Cons up a dummy header
760 		 * to pacify bpf.  This is safe because bpf
761 		 * will only read from the mbuf (i.e., it won't
762 		 * try to free it or keep a pointer a to it).
763 		 */
764 		u_int32_t af = AF_INET6;
765 		bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
766 	}
767 
768 	/*
769 	 * Put the packet to the network layer input queue according to the
770 	 * specified address family.
771 	 * See net/if_gif.c for possible issues with packet processing
772 	 * reorder due to extra queueing.
773 	 */
774 	ifp->if_ipackets++;
775 	ifp->if_ibytes += m->m_pkthdr.len;
776 	netisr_dispatch(NETISR_IPV6, m);
777 }
778 
779 /* ARGSUSED */
780 static void
781 stf_rtrequest(cmd, rt, info)
782 	int cmd;
783 	struct rtentry *rt;
784 	struct rt_addrinfo *info;
785 {
786 	RT_LOCK_ASSERT(rt);
787 	rt->rt_rmx.rmx_mtu = IPV6_MMTU;
788 }
789 
790 static int
791 stf_ioctl(ifp, cmd, data)
792 	struct ifnet *ifp;
793 	u_long cmd;
794 	caddr_t data;
795 {
796 	struct ifaddr *ifa;
797 	struct ifreq *ifr;
798 	struct sockaddr_in6 *sin6;
799 	struct in_addr addr;
800 	int error;
801 
802 	error = 0;
803 	switch (cmd) {
804 	case SIOCSIFADDR:
805 		ifa = (struct ifaddr *)data;
806 		if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
807 			error = EAFNOSUPPORT;
808 			break;
809 		}
810 		sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
811 		if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) {
812 			error = EINVAL;
813 			break;
814 		}
815 		bcopy(GET_V4(&sin6->sin6_addr), &addr, sizeof(addr));
816 		if (isrfc1918addr(&addr)) {
817 			error = EINVAL;
818 			break;
819 		}
820 
821 		ifa->ifa_rtrequest = stf_rtrequest;
822 		ifp->if_flags |= IFF_UP;
823 		break;
824 
825 	case SIOCADDMULTI:
826 	case SIOCDELMULTI:
827 		ifr = (struct ifreq *)data;
828 		if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
829 			;
830 		else
831 			error = EAFNOSUPPORT;
832 		break;
833 
834 	default:
835 		error = EINVAL;
836 		break;
837 	}
838 
839 	return error;
840 }
841