1 /* $FreeBSD$ */
2 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */
3
4 /*-
5 * SPDX-License-Identifier: BSD-3-Clause
6 *
7 * Copyright (C) 2000 WIDE Project.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the project nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 /*
36 * 6to4 interface, based on RFC3056.
37 *
38 * 6to4 interface is NOT capable of link-layer (I mean, IPv4) multicasting.
39 * There is no address mapping defined from IPv6 multicast address to IPv4
40 * address. Therefore, we do not have IFF_MULTICAST on the interface.
41 *
42 * Due to the lack of address mapping for link-local addresses, we cannot
43 * throw packets toward link-local addresses (fe80::x). Also, we cannot throw
44 * packets to link-local multicast addresses (ff02::x).
45 *
46 * Here are interesting symptoms due to the lack of link-local address:
47 *
48 * Unicast routing exchange:
49 * - RIPng: Impossible. Uses link-local multicast packet toward ff02::9,
50 * and link-local addresses as nexthop.
51 * - OSPFv6: Impossible. OSPFv6 assumes that there's link-local address
52 * assigned to the link, and makes use of them. Also, HELLO packets use
53 * link-local multicast addresses (ff02::5 and ff02::6).
54 * - BGP4+: Maybe. You can only use global address as nexthop, and global
55 * address as TCP endpoint address.
56 *
57 * Multicast routing protocols:
58 * - PIM: Hello packet cannot be used to discover adjacent PIM routers.
59 * Adjacent PIM routers must be configured manually (is it really spec-wise
60 * correct thing to do?).
61 *
62 * ICMPv6:
63 * - Redirects cannot be used due to the lack of link-local address.
64 *
65 * stf interface does not have, and will not need, a link-local address.
66 * It seems to have no real benefit and does not help the above symptoms much.
67 * Even if we assign link-locals to interface, we cannot really
68 * use link-local unicast/multicast on top of 6to4 cloud (since there's no
69 * encapsulation defined for link-local address), and the above analysis does
70 * not change. RFC3056 does not mandate the assignment of link-local address
71 * either.
72 *
73 * 6to4 interface has security issues. Refer to
74 * http://playground.iijlab.net/i-d/draft-itojun-ipv6-transition-abuse-00.txt
75 * for details. The code tries to filter out some of malicious packets.
76 * Note that there is no way to be 100% secure.
77 */
78
79 #include <sys/param.h>
80 #include <sys/systm.h>
81 #include <sys/socket.h>
82 #include <sys/sockio.h>
83 #include <sys/mbuf.h>
84 #include <sys/errno.h>
85 #include <sys/kernel.h>
86 #include <sys/lock.h>
87 #include <sys/module.h>
88 #include <sys/proc.h>
89 #include <sys/queue.h>
90 #include <sys/rmlock.h>
91 #include <sys/sysctl.h>
92 #include <machine/cpu.h>
93
94 #include <sys/malloc.h>
95
96 #include <net/if.h>
97 #include <net/if_var.h>
98 #include <net/if_clone.h>
99 #include <net/route.h>
100 #include <net/route/nhop.h>
101 #include <net/netisr.h>
102 #include <net/if_types.h>
103 #include <net/vnet.h>
104
105 #include <netinet/in.h>
106 #include <netinet/in_fib.h>
107 #include <netinet/in_systm.h>
108 #include <netinet/ip.h>
109 #include <netinet/ip_var.h>
110 #include <netinet/in_var.h>
111
112 #include <netinet/ip6.h>
113 #include <netinet6/ip6_var.h>
114 #include <netinet6/in6_var.h>
115 #include <netinet/ip_ecn.h>
116
117 #include <netinet/ip_encap.h>
118
119 #include <machine/stdarg.h>
120
121 #include <net/bpf.h>
122
123 #include <security/mac/mac_framework.h>
124
125 SYSCTL_DECL(_net_link);
126 static SYSCTL_NODE(_net_link, IFT_STF, stf, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
127 "6to4 Interface");
128
129 static int stf_permit_rfc1918 = 0;
130 SYSCTL_INT(_net_link_stf, OID_AUTO, permit_rfc1918, CTLFLAG_RWTUN,
131 &stf_permit_rfc1918, 0, "Permit the use of private IPv4 addresses");
132
133 #define STFUNIT 0
134
135 #define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002)
136
137 /*
138 * XXX: Return a pointer with 16-bit aligned. Don't cast it to
139 * struct in_addr *; use bcopy() instead.
140 */
141 #define GET_V4(x) (&(x)->s6_addr16[1])
142
143 struct stf_softc {
144 struct ifnet *sc_ifp;
145 u_int sc_fibnum;
146 const struct encaptab *encap_cookie;
147 };
148 #define STF2IFP(sc) ((sc)->sc_ifp)
149
150 static const char stfname[] = "stf";
151
152 static MALLOC_DEFINE(M_STF, stfname, "6to4 Tunnel Interface");
153 static const int ip_stf_ttl = 40;
154
155 static int in_stf_input(struct mbuf *, int, int, void *);
156 static char *stfnames[] = {"stf0", "stf", "6to4", NULL};
157
158 static int stfmodevent(module_t, int, void *);
159 static int stf_encapcheck(const struct mbuf *, int, int, void *);
160 static int stf_getsrcifa6(struct ifnet *, struct in6_addr *, struct in6_addr *);
161 static int stf_output(struct ifnet *, struct mbuf *, const struct sockaddr *,
162 struct route *);
163 static int isrfc1918addr(struct in_addr *);
164 static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
165 struct ifnet *);
166 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
167 struct ifnet *);
168 static int stf_ioctl(struct ifnet *, u_long, caddr_t);
169
170 static int stf_clone_match(struct if_clone *, const char *);
171 static int stf_clone_create(struct if_clone *, char *, size_t, caddr_t);
172 static int stf_clone_destroy(struct if_clone *, struct ifnet *);
173 VNET_DEFINE_STATIC(struct if_clone *, stf_cloner);
174 #define V_stf_cloner VNET(stf_cloner)
175
176 static const struct encap_config ipv4_encap_cfg = {
177 .proto = IPPROTO_IPV6,
178 .min_length = sizeof(struct ip),
179 .exact_match = (sizeof(in_addr_t) << 3) + 8,
180 .check = stf_encapcheck,
181 .input = in_stf_input
182 };
183
184 static int
stf_clone_match(struct if_clone * ifc,const char * name)185 stf_clone_match(struct if_clone *ifc, const char *name)
186 {
187 int i;
188
189 for(i = 0; stfnames[i] != NULL; i++) {
190 if (strcmp(stfnames[i], name) == 0)
191 return (1);
192 }
193
194 return (0);
195 }
196
197 static int
stf_clone_create(struct if_clone * ifc,char * name,size_t len,caddr_t params)198 stf_clone_create(struct if_clone *ifc, char *name, size_t len, caddr_t params)
199 {
200 char *dp;
201 int err, unit, wildcard;
202 struct stf_softc *sc;
203 struct ifnet *ifp;
204
205 err = ifc_name2unit(name, &unit);
206 if (err != 0)
207 return (err);
208 wildcard = (unit < 0);
209
210 /*
211 * We can only have one unit, but since unit allocation is
212 * already locked, we use it to keep from allocating extra
213 * interfaces.
214 */
215 unit = STFUNIT;
216 err = ifc_alloc_unit(ifc, &unit);
217 if (err != 0)
218 return (err);
219
220 sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
221 ifp = STF2IFP(sc) = if_alloc(IFT_STF);
222 if (ifp == NULL) {
223 free(sc, M_STF);
224 ifc_free_unit(ifc, unit);
225 return (ENOSPC);
226 }
227 ifp->if_softc = sc;
228 sc->sc_fibnum = curthread->td_proc->p_fibnum;
229
230 /*
231 * Set the name manually rather then using if_initname because
232 * we don't conform to the default naming convention for interfaces.
233 * In the wildcard case, we need to update the name.
234 */
235 if (wildcard) {
236 for (dp = name; *dp != '\0'; dp++);
237 if (snprintf(dp, len - (dp-name), "%d", unit) >
238 len - (dp-name) - 1) {
239 /*
240 * This can only be a programmer error and
241 * there's no straightforward way to recover if
242 * it happens.
243 */
244 panic("if_clone_create(): interface name too long");
245 }
246 }
247 strlcpy(ifp->if_xname, name, IFNAMSIZ);
248 ifp->if_dname = stfname;
249 ifp->if_dunit = IF_DUNIT_NONE;
250
251 sc->encap_cookie = ip_encap_attach(&ipv4_encap_cfg, sc, M_WAITOK);
252 if (sc->encap_cookie == NULL) {
253 if_printf(ifp, "attach failed\n");
254 free(sc, M_STF);
255 ifc_free_unit(ifc, unit);
256 return (ENOMEM);
257 }
258
259 ifp->if_mtu = IPV6_MMTU;
260 ifp->if_ioctl = stf_ioctl;
261 ifp->if_output = stf_output;
262 ifp->if_snd.ifq_maxlen = ifqmaxlen;
263 if_attach(ifp);
264 bpfattach(ifp, DLT_NULL, sizeof(u_int32_t));
265 return (0);
266 }
267
268 static int
stf_clone_destroy(struct if_clone * ifc,struct ifnet * ifp)269 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp)
270 {
271 struct stf_softc *sc = ifp->if_softc;
272 int err __unused;
273
274 err = ip_encap_detach(sc->encap_cookie);
275 KASSERT(err == 0, ("Unexpected error detaching encap_cookie"));
276 bpfdetach(ifp);
277 if_detach(ifp);
278 if_free(ifp);
279
280 free(sc, M_STF);
281 ifc_free_unit(ifc, STFUNIT);
282
283 return (0);
284 }
285
286 static void
vnet_stf_init(const void * unused __unused)287 vnet_stf_init(const void *unused __unused)
288 {
289 V_stf_cloner = if_clone_advanced(stfname, 0, stf_clone_match,
290 stf_clone_create, stf_clone_destroy);
291 }
292 VNET_SYSINIT(vnet_stf_init, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_init, NULL);
293
294 static void
vnet_stf_uninit(const void * unused __unused)295 vnet_stf_uninit(const void *unused __unused)
296 {
297 if_clone_detach(V_stf_cloner);
298 V_stf_cloner = NULL;
299 }
300 VNET_SYSUNINIT(vnet_stf_uninit, SI_SUB_PSEUDO, SI_ORDER_ANY, vnet_stf_uninit,
301 NULL);
302
303 static int
stfmodevent(module_t mod,int type,void * data)304 stfmodevent(module_t mod, int type, void *data)
305 {
306
307 switch (type) {
308 case MOD_LOAD:
309 /* Done in vnet_stf_init() */
310 break;
311 case MOD_UNLOAD:
312 /* Done in vnet_stf_uninit() */
313 break;
314 default:
315 return (EOPNOTSUPP);
316 }
317
318 return (0);
319 }
320
321 static moduledata_t stf_mod = {
322 "if_stf",
323 stfmodevent,
324 0
325 };
326
327 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
328
329 static int
stf_encapcheck(const struct mbuf * m,int off,int proto,void * arg)330 stf_encapcheck(const struct mbuf *m, int off, int proto, void *arg)
331 {
332 struct ip ip;
333 struct stf_softc *sc;
334 struct in_addr a, b, mask;
335 struct in6_addr addr6, mask6;
336
337 sc = (struct stf_softc *)arg;
338 if (sc == NULL)
339 return (0);
340
341 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0)
342 return (0);
343
344 /* IFF_LINK0 means "no decapsulation" */
345 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0)
346 return (0);
347
348 if (proto != IPPROTO_IPV6)
349 return (0);
350
351 m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
352
353 if (ip.ip_v != 4)
354 return (0);
355
356 if (stf_getsrcifa6(STF2IFP(sc), &addr6, &mask6) != 0)
357 return (0);
358
359 /*
360 * check if IPv4 dst matches the IPv4 address derived from the
361 * local 6to4 address.
362 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
363 */
364 if (bcmp(GET_V4(&addr6), &ip.ip_dst, sizeof(ip.ip_dst)) != 0)
365 return (0);
366
367 /*
368 * check if IPv4 src matches the IPv4 address derived from the
369 * local 6to4 address masked by prefixmask.
370 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
371 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
372 */
373 bzero(&a, sizeof(a));
374 bcopy(GET_V4(&addr6), &a, sizeof(a));
375 bcopy(GET_V4(&mask6), &mask, sizeof(mask));
376 a.s_addr &= mask.s_addr;
377 b = ip.ip_src;
378 b.s_addr &= mask.s_addr;
379 if (a.s_addr != b.s_addr)
380 return (0);
381
382 /* stf interface makes single side match only */
383 return (32);
384 }
385
386 static int
stf_getsrcifa6(struct ifnet * ifp,struct in6_addr * addr,struct in6_addr * mask)387 stf_getsrcifa6(struct ifnet *ifp, struct in6_addr *addr, struct in6_addr *mask)
388 {
389 struct rm_priotracker in_ifa_tracker;
390 struct ifaddr *ia;
391 struct in_ifaddr *ia4;
392 struct in6_ifaddr *ia6;
393 struct sockaddr_in6 *sin6;
394 struct in_addr in;
395
396 NET_EPOCH_ASSERT();
397
398 CK_STAILQ_FOREACH(ia, &ifp->if_addrhead, ifa_link) {
399 if (ia->ifa_addr->sa_family != AF_INET6)
400 continue;
401 sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
402 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
403 continue;
404
405 bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
406 IN_IFADDR_RLOCK(&in_ifa_tracker);
407 LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
408 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
409 break;
410 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
411 if (ia4 == NULL)
412 continue;
413
414 ia6 = (struct in6_ifaddr *)ia;
415
416 *addr = sin6->sin6_addr;
417 *mask = ia6->ia_prefixmask.sin6_addr;
418 return (0);
419 }
420
421 return (ENOENT);
422 }
423
424 static int
stf_output(struct ifnet * ifp,struct mbuf * m,const struct sockaddr * dst,struct route * ro)425 stf_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *dst,
426 struct route *ro)
427 {
428 struct stf_softc *sc;
429 const struct sockaddr_in6 *dst6;
430 struct in_addr in4;
431 const void *ptr;
432 u_int8_t tos;
433 struct ip *ip;
434 struct ip6_hdr *ip6;
435 struct in6_addr addr6, mask6;
436 int error;
437
438 #ifdef MAC
439 error = mac_ifnet_check_transmit(ifp, m);
440 if (error) {
441 m_freem(m);
442 return (error);
443 }
444 #endif
445
446 sc = ifp->if_softc;
447 dst6 = (const struct sockaddr_in6 *)dst;
448
449 /* just in case */
450 if ((ifp->if_flags & IFF_UP) == 0) {
451 m_freem(m);
452 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
453 return (ENETDOWN);
454 }
455
456 /*
457 * If we don't have an ip4 address that match my inner ip6 address,
458 * we shouldn't generate output. Without this check, we'll end up
459 * using wrong IPv4 source.
460 */
461 if (stf_getsrcifa6(ifp, &addr6, &mask6) != 0) {
462 m_freem(m);
463 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
464 return (ENETDOWN);
465 }
466
467 if (m->m_len < sizeof(*ip6)) {
468 m = m_pullup(m, sizeof(*ip6));
469 if (!m) {
470 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
471 return (ENOBUFS);
472 }
473 }
474 ip6 = mtod(m, struct ip6_hdr *);
475 tos = IPV6_TRAFFIC_CLASS(ip6);
476
477 /*
478 * Pickup the right outer dst addr from the list of candidates.
479 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
480 */
481 ptr = NULL;
482 if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
483 ptr = GET_V4(&ip6->ip6_dst);
484 else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
485 ptr = GET_V4(&dst6->sin6_addr);
486 else {
487 m_freem(m);
488 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
489 return (ENETUNREACH);
490 }
491 bcopy(ptr, &in4, sizeof(in4));
492
493 if (bpf_peers_present(ifp->if_bpf)) {
494 /*
495 * We need to prepend the address family as
496 * a four byte field. Cons up a dummy header
497 * to pacify bpf. This is safe because bpf
498 * will only read from the mbuf (i.e., it won't
499 * try to free it or keep a pointer a to it).
500 */
501 u_int af = AF_INET6;
502 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
503 }
504
505 M_PREPEND(m, sizeof(struct ip), M_NOWAIT);
506 if (m == NULL) {
507 if_inc_counter(ifp, IFCOUNTER_OERRORS, 1);
508 return (ENOBUFS);
509 }
510 ip = mtod(m, struct ip *);
511
512 bzero(ip, sizeof(*ip));
513
514 bcopy(GET_V4(&addr6), &ip->ip_src, sizeof(ip->ip_src));
515 bcopy(&in4, &ip->ip_dst, sizeof(ip->ip_dst));
516 ip->ip_p = IPPROTO_IPV6;
517 ip->ip_ttl = ip_stf_ttl;
518 ip->ip_len = htons(m->m_pkthdr.len);
519 if (ifp->if_flags & IFF_LINK1)
520 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
521 else
522 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
523
524 M_SETFIB(m, sc->sc_fibnum);
525 if_inc_counter(ifp, IFCOUNTER_OPACKETS, 1);
526 error = ip_output(m, NULL, NULL, 0, NULL, NULL);
527
528 return (error);
529 }
530
531 static int
isrfc1918addr(struct in_addr * in)532 isrfc1918addr(struct in_addr *in)
533 {
534 /*
535 * returns 1 if private address range:
536 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
537 */
538 if (stf_permit_rfc1918 == 0 && (
539 (ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
540 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
541 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168))
542 return (1);
543
544 return (0);
545 }
546
547 static int
stf_checkaddr4(struct stf_softc * sc,struct in_addr * in,struct ifnet * inifp)548 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in, struct ifnet *inifp)
549 {
550 struct rm_priotracker in_ifa_tracker;
551 struct in_ifaddr *ia4;
552
553 /*
554 * reject packets with the following address:
555 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
556 */
557 if (IN_MULTICAST(ntohl(in->s_addr)))
558 return (-1);
559 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
560 case 0: case 127: case 255:
561 return (-1);
562 }
563
564 /*
565 * reject packets with private address range.
566 * (requirement from RFC3056 section 2 1st paragraph)
567 */
568 if (isrfc1918addr(in))
569 return (-1);
570
571 /*
572 * reject packets with broadcast
573 */
574 IN_IFADDR_RLOCK(&in_ifa_tracker);
575 CK_STAILQ_FOREACH(ia4, &V_in_ifaddrhead, ia_link) {
576 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
577 continue;
578 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr) {
579 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
580 return (-1);
581 }
582 }
583 IN_IFADDR_RUNLOCK(&in_ifa_tracker);
584
585 /*
586 * perform ingress filter
587 */
588 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) {
589 struct nhop_object *nh;
590
591 NET_EPOCH_ASSERT();
592 nh = fib4_lookup(sc->sc_fibnum, *in, 0, 0, 0);
593 if (nh == NULL)
594 return (-1);
595
596 if (nh->nh_ifp != inifp)
597 return (-1);
598 }
599
600 return (0);
601 }
602
603 static int
stf_checkaddr6(struct stf_softc * sc,struct in6_addr * in6,struct ifnet * inifp)604 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6, struct ifnet *inifp)
605 {
606 /*
607 * check 6to4 addresses
608 */
609 if (IN6_IS_ADDR_6TO4(in6)) {
610 struct in_addr in4;
611 bcopy(GET_V4(in6), &in4, sizeof(in4));
612 return (stf_checkaddr4(sc, &in4, inifp));
613 }
614
615 /*
616 * reject anything that look suspicious. the test is implemented
617 * in ip6_input too, but we check here as well to
618 * (1) reject bad packets earlier, and
619 * (2) to be safe against future ip6_input change.
620 */
621 if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
622 return (-1);
623
624 return (0);
625 }
626
627 static int
in_stf_input(struct mbuf * m,int off,int proto,void * arg)628 in_stf_input(struct mbuf *m, int off, int proto, void *arg)
629 {
630 struct stf_softc *sc = arg;
631 struct ip *ip;
632 struct ip6_hdr *ip6;
633 u_int8_t otos, itos;
634 struct ifnet *ifp;
635
636 NET_EPOCH_ASSERT();
637
638 if (proto != IPPROTO_IPV6) {
639 m_freem(m);
640 return (IPPROTO_DONE);
641 }
642
643 ip = mtod(m, struct ip *);
644 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) {
645 m_freem(m);
646 return (IPPROTO_DONE);
647 }
648
649 ifp = STF2IFP(sc);
650
651 #ifdef MAC
652 mac_ifnet_create_mbuf(ifp, m);
653 #endif
654
655 /*
656 * perform sanity check against outer src/dst.
657 * for source, perform ingress filter as well.
658 */
659 if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
660 stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
661 m_freem(m);
662 return (IPPROTO_DONE);
663 }
664
665 otos = ip->ip_tos;
666 m_adj(m, off);
667
668 if (m->m_len < sizeof(*ip6)) {
669 m = m_pullup(m, sizeof(*ip6));
670 if (!m)
671 return (IPPROTO_DONE);
672 }
673 ip6 = mtod(m, struct ip6_hdr *);
674
675 /*
676 * perform sanity check against inner src/dst.
677 * for source, perform ingress filter as well.
678 */
679 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
680 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
681 m_freem(m);
682 return (IPPROTO_DONE);
683 }
684
685 itos = IPV6_TRAFFIC_CLASS(ip6);
686 if ((ifp->if_flags & IFF_LINK1) != 0)
687 ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
688 else
689 ip_ecn_egress(ECN_NOCARE, &otos, &itos);
690 ip6->ip6_flow &= ~htonl(0xff << 20);
691 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
692
693 m->m_pkthdr.rcvif = ifp;
694
695 if (bpf_peers_present(ifp->if_bpf)) {
696 /*
697 * We need to prepend the address family as
698 * a four byte field. Cons up a dummy header
699 * to pacify bpf. This is safe because bpf
700 * will only read from the mbuf (i.e., it won't
701 * try to free it or keep a pointer a to it).
702 */
703 u_int32_t af = AF_INET6;
704 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
705 }
706
707 /*
708 * Put the packet to the network layer input queue according to the
709 * specified address family.
710 * See net/if_gif.c for possible issues with packet processing
711 * reorder due to extra queueing.
712 */
713 if_inc_counter(ifp, IFCOUNTER_IPACKETS, 1);
714 if_inc_counter(ifp, IFCOUNTER_IBYTES, m->m_pkthdr.len);
715 M_SETFIB(m, ifp->if_fib);
716 netisr_dispatch(NETISR_IPV6, m);
717 return (IPPROTO_DONE);
718 }
719
720 static int
stf_ioctl(struct ifnet * ifp,u_long cmd,caddr_t data)721 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
722 {
723 struct ifaddr *ifa;
724 struct ifreq *ifr;
725 struct sockaddr_in6 *sin6;
726 struct in_addr addr;
727 int error, mtu;
728
729 error = 0;
730 switch (cmd) {
731 case SIOCSIFADDR:
732 ifa = (struct ifaddr *)data;
733 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
734 error = EAFNOSUPPORT;
735 break;
736 }
737 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
738 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) {
739 error = EINVAL;
740 break;
741 }
742 bcopy(GET_V4(&sin6->sin6_addr), &addr, sizeof(addr));
743 if (isrfc1918addr(&addr)) {
744 error = EINVAL;
745 break;
746 }
747
748 ifp->if_flags |= IFF_UP;
749 ifp->if_drv_flags |= IFF_DRV_RUNNING;
750 break;
751
752 case SIOCADDMULTI:
753 case SIOCDELMULTI:
754 ifr = (struct ifreq *)data;
755 if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
756 ;
757 else
758 error = EAFNOSUPPORT;
759 break;
760
761 case SIOCGIFMTU:
762 break;
763
764 case SIOCSIFMTU:
765 ifr = (struct ifreq *)data;
766 mtu = ifr->ifr_mtu;
767 /* RFC 4213 3.2 ideal world MTU */
768 if (mtu < IPV6_MINMTU || mtu > IF_MAXMTU - 20)
769 return (EINVAL);
770 ifp->if_mtu = mtu;
771 break;
772
773 default:
774 error = EINVAL;
775 break;
776 }
777
778 return (error);
779 }
780