2 /* $KAME: if_stf.c,v 1.73 2001/12/03 11:08:30 keiichi Exp $ */
5 * Copyright (C) 2000 WIDE Project.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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.
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
34 * 6to4 interface, based on RFC3056.
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.
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).
44 * Here are interesting symptoms due to the lack of link-local address:
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.
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?).
61 * - Redirects cannot be used due to the lack of link-local address.
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
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.
78 #include "opt_inet6.h"
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/socket.h>
84 #include <sys/sockio.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>
94 #include <sys/malloc.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>
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>
109 #include <netinet/ip6.h>
110 #include <netinet6/ip6_var.h>
111 #include <netinet6/in6_var.h>
112 #include <netinet/ip_ecn.h>
114 #include <netinet/ip_encap.h>
116 #include <machine/stdarg.h>
118 #include <net/net_osdep.h>
122 #define STFNAME "stf"
125 #define IN6_IS_ADDR_6TO4(x) (ntohs((x)->s6_addr16[0]) == 0x2002)
128 * XXX: Return a pointer with 16-bit aligned. Don't cast it to
129 * struct in_addr *; use bcopy() instead.
131 #define GET_V4(x) ((caddr_t)(&(x)->s6_addr16[1]))
134 struct ifnet *sc_ifp;
136 struct route __sc_ro4;
137 struct route_in6 __sc_ro6; /* just for safety */
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 */
143 #define STF2IFP(sc) ((sc)->sc_ifp)
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
151 static struct mtx stf_mtx;
152 static LIST_HEAD(, stf_softc) stf_softc_list;
154 static MALLOC_DEFINE(M_STF, STFNAME, "6to4 Tunnel Interface");
155 static const int ip_stf_ttl = 40;
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,
166 static char *stfnames[] = {"stf0", "stf", "6to4", NULL};
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 *,
173 static int isrfc1918addr(struct in_addr *);
174 static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
176 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
178 static void stf_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
179 static int stf_ioctl(struct ifnet *, u_long, caddr_t);
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);
188 stf_clone_match(struct if_clone *ifc, const char *name)
192 for(i = 0; stfnames[i] != NULL; i++) {
193 if (strcmp(stfnames[i], name) == 0)
201 stf_clone_create(struct if_clone *ifc, char *name, size_t len)
204 struct stf_softc *sc;
208 * We can only have one unit, but since unit allocation is
209 * already locked, we use it to keep from allocating extra
213 err = ifc_alloc_unit(ifc, &unit);
217 sc = malloc(sizeof(struct stf_softc), M_STF, M_WAITOK | M_ZERO);
218 ifp = sc->sc_ifp = if_alloc(IFT_STF);
221 ifc_free_unit(ifc, unit);
225 * Set the name manually rather then using if_initname because
226 * we don't conform to the default naming convention for interfaces.
228 strlcpy(ifp->if_xname, name, IFNAMSIZ);
229 ifp->if_dname = ifc->ifc_name;
230 ifp->if_dunit = IF_DUNIT_NONE;
232 sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
233 stf_encapcheck, &in_stf_protosw, sc);
234 if (sc->encap_cookie == NULL) {
235 if_printf(ifp, "attach failed\n");
237 ifc_free_unit(ifc, unit);
241 ifp->if_mtu = IPV6_MMTU;
242 ifp->if_ioctl = stf_ioctl;
243 ifp->if_output = stf_output;
244 ifp->if_snd.ifq_maxlen = IFQ_MAXLEN;
246 bpfattach(ifp, DLT_NULL, sizeof(u_int));
248 LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
249 mtx_unlock(&stf_mtx);
254 stf_destroy(struct stf_softc *sc)
258 err = encap_detach(sc->encap_cookie);
259 KASSERT(err == 0, ("Unexpected error detaching encap_cookie"));
260 bpfdetach(STF2IFP(sc));
261 if_detach(STF2IFP(sc));
262 if_free(STF2IFP(sc));
268 stf_clone_destroy(struct if_clone *ifc, struct ifnet *ifp)
270 struct stf_softc *sc = ifp->if_softc;
273 LIST_REMOVE(sc, sc_list);
274 mtx_unlock(&stf_mtx);
277 ifc_free_unit(ifc, STFUNIT);
283 stfmodevent(mod, type, data)
288 struct stf_softc *sc;
292 mtx_init(&stf_mtx, "stf_mtx", NULL, MTX_DEF);
293 LIST_INIT(&stf_softc_list);
294 if_clone_attach(&stf_cloner);
298 if_clone_detach(&stf_cloner);
301 while ((sc = LIST_FIRST(&stf_softc_list)) != NULL) {
302 LIST_REMOVE(sc, sc_list);
303 mtx_unlock(&stf_mtx);
307 mtx_unlock(&stf_mtx);
308 mtx_destroy(&stf_mtx);
317 static moduledata_t stf_mod = {
323 DECLARE_MODULE(if_stf, stf_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
326 stf_encapcheck(m, off, proto, arg)
327 const struct mbuf *m;
333 struct in6_ifaddr *ia6;
334 struct stf_softc *sc;
335 struct in_addr a, b, mask;
337 sc = (struct stf_softc *)arg;
341 if ((STF2IFP(sc)->if_flags & IFF_UP) == 0)
344 /* IFF_LINK0 means "no decapsulation" */
345 if ((STF2IFP(sc)->if_flags & IFF_LINK0) != 0)
348 if (proto != IPPROTO_IPV6)
351 /* LINTED const cast */
352 m_copydata((struct mbuf *)(uintptr_t)m, 0, sizeof(ip), (caddr_t)&ip);
357 ia6 = stf_getsrcifa6(STF2IFP(sc));
362 * check if IPv4 dst matches the IPv4 address derived from the
363 * local 6to4 address.
364 * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
366 if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
367 sizeof(ip.ip_dst)) != 0)
371 * check if IPv4 src matches the IPv4 address derived from the
372 * local 6to4 address masked by prefixmask.
373 * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
374 * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
376 bzero(&a, sizeof(a));
377 bcopy(GET_V4(&ia6->ia_addr.sin6_addr), &a, sizeof(a));
378 bcopy(GET_V4(&ia6->ia_prefixmask.sin6_addr), &mask, sizeof(mask));
379 a.s_addr &= mask.s_addr;
381 b.s_addr &= mask.s_addr;
382 if (a.s_addr != b.s_addr)
385 /* stf interface makes single side match only */
389 static struct in6_ifaddr *
394 struct in_ifaddr *ia4;
395 struct sockaddr_in6 *sin6;
398 for (ia = TAILQ_FIRST(&ifp->if_addrlist);
400 ia = TAILQ_NEXT(ia, ifa_list))
402 if (ia->ifa_addr == NULL)
404 if (ia->ifa_addr->sa_family != AF_INET6)
406 sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
407 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
410 bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
411 LIST_FOREACH(ia4, INADDR_HASH(in.s_addr), ia_hash)
412 if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
417 return (struct in6_ifaddr *)ia;
424 stf_output(ifp, m, dst, rt)
427 struct sockaddr *dst;
430 struct stf_softc *sc;
431 struct sockaddr_in6 *dst6;
434 struct sockaddr_in *dst4;
438 struct in6_ifaddr *ia6;
442 error = mac_check_ifnet_transmit(ifp, m);
450 dst6 = (struct sockaddr_in6 *)dst;
453 if ((ifp->if_flags & IFF_UP) == 0) {
460 * If we don't have an ip4 address that match my inner ip6 address,
461 * we shouldn't generate output. Without this check, we'll end up
462 * using wrong IPv4 source.
464 ia6 = stf_getsrcifa6(ifp);
471 if (m->m_len < sizeof(*ip6)) {
472 m = m_pullup(m, sizeof(*ip6));
478 ip6 = mtod(m, struct ip6_hdr *);
479 tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
482 * Pickup the right outer dst addr from the list of candidates.
483 * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
486 if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
487 ptr = GET_V4(&ip6->ip6_dst);
488 else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
489 ptr = GET_V4(&dst6->sin6_addr);
495 bcopy(ptr, &in4, sizeof(in4));
499 * We need to prepend the address family as
500 * a four byte field. Cons up a dummy header
501 * to pacify bpf. This is safe because bpf
502 * will only read from the mbuf (i.e., it won't
503 * try to free it or keep a pointer a to it).
505 u_int32_t af = AF_INET6;
506 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
509 M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
510 if (m && m->m_len < sizeof(struct ip))
511 m = m_pullup(m, sizeof(struct ip));
516 ip = mtod(m, struct ip *);
518 bzero(ip, sizeof(*ip));
520 bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
521 &ip->ip_src, sizeof(ip->ip_src));
522 bcopy(&in4, &ip->ip_dst, sizeof(ip->ip_dst));
523 ip->ip_p = IPPROTO_IPV6;
524 ip->ip_ttl = ip_stf_ttl;
525 ip->ip_len = m->m_pkthdr.len; /*host order*/
526 if (ifp->if_flags & IFF_LINK1)
527 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
529 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
532 * XXXRW: Locking of sc_ro required.
534 dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
535 if (dst4->sin_family != AF_INET ||
536 bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
537 /* cache route doesn't match */
538 dst4->sin_family = AF_INET;
539 dst4->sin_len = sizeof(struct sockaddr_in);
540 bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
541 if (sc->sc_ro.ro_rt) {
542 RTFREE(sc->sc_ro.ro_rt);
543 sc->sc_ro.ro_rt = NULL;
547 if (sc->sc_ro.ro_rt == NULL) {
549 if (sc->sc_ro.ro_rt == NULL) {
557 return ip_output(m, NULL, &sc->sc_ro, 0, NULL, NULL);
565 * returns 1 if private address range:
566 * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
568 if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
569 (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
570 (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
577 stf_checkaddr4(sc, in, inifp)
578 struct stf_softc *sc;
580 struct ifnet *inifp; /* incoming interface */
582 struct in_ifaddr *ia4;
585 * reject packets with the following address:
586 * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
588 if (IN_MULTICAST(ntohl(in->s_addr)))
590 switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
591 case 0: case 127: case 255:
596 * reject packets with private address range.
597 * (requirement from RFC3056 section 2 1st paragraph)
599 if (isrfc1918addr(in))
603 * reject packets with broadcast
605 for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
607 ia4 = TAILQ_NEXT(ia4, ia_link))
609 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
611 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
616 * perform ingress filter
618 if (sc && (STF2IFP(sc)->if_flags & IFF_LINK2) == 0 && inifp) {
619 struct sockaddr_in sin;
622 bzero(&sin, sizeof(sin));
623 sin.sin_family = AF_INET;
624 sin.sin_len = sizeof(struct sockaddr_in);
626 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
627 if (!rt || rt->rt_ifp != inifp) {
629 log(LOG_WARNING, "%s: packet from 0x%x dropped "
630 "due to ingress filter\n", if_name(STF2IFP(sc)),
631 (u_int32_t)ntohl(sin.sin_addr.s_addr));
644 stf_checkaddr6(sc, in6, inifp)
645 struct stf_softc *sc;
646 struct in6_addr *in6;
647 struct ifnet *inifp; /* incoming interface */
650 * check 6to4 addresses
652 if (IN6_IS_ADDR_6TO4(in6)) {
654 bcopy(GET_V4(in6), &in4, sizeof(in4));
655 return stf_checkaddr4(sc, &in4, inifp);
659 * reject anything that look suspicious. the test is implemented
660 * in ip6_input too, but we check here as well to
661 * (1) reject bad packets earlier, and
662 * (2) to be safe against future ip6_input change.
664 if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
676 struct stf_softc *sc;
682 proto = mtod(m, struct ip *)->ip_p;
684 if (proto != IPPROTO_IPV6) {
689 ip = mtod(m, struct ip *);
691 sc = (struct stf_softc *)encap_getarg(m);
693 if (sc == NULL || (STF2IFP(sc)->if_flags & IFF_UP) == 0) {
701 mac_create_mbuf_from_ifnet(ifp, m);
705 * perform sanity check against outer src/dst.
706 * for source, perform ingress filter as well.
708 if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
709 stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
717 if (m->m_len < sizeof(*ip6)) {
718 m = m_pullup(m, sizeof(*ip6));
722 ip6 = mtod(m, struct ip6_hdr *);
725 * perform sanity check against inner src/dst.
726 * for source, perform ingress filter as well.
728 if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
729 stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
734 itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
735 if ((ifp->if_flags & IFF_LINK1) != 0)
736 ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
738 ip_ecn_egress(ECN_NOCARE, &otos, &itos);
739 ip6->ip6_flow &= ~htonl(0xff << 20);
740 ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
742 m->m_pkthdr.rcvif = ifp;
746 * We need to prepend the address family as
747 * a four byte field. Cons up a dummy header
748 * to pacify bpf. This is safe because bpf
749 * will only read from the mbuf (i.e., it won't
750 * try to free it or keep a pointer a to it).
752 u_int32_t af = AF_INET6;
753 bpf_mtap2(ifp->if_bpf, &af, sizeof(af), m);
757 * Put the packet to the network layer input queue according to the
758 * specified address family.
759 * See net/if_gif.c for possible issues with packet processing
760 * reorder due to extra queueing.
763 ifp->if_ibytes += m->m_pkthdr.len;
764 netisr_dispatch(NETISR_IPV6, m);
769 stf_rtrequest(cmd, rt, info)
772 struct rt_addrinfo *info;
775 rt->rt_rmx.rmx_mtu = IPV6_MMTU;
779 stf_ioctl(ifp, cmd, data)
786 struct sockaddr_in6 *sin6;
793 ifa = (struct ifaddr *)data;
794 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
795 error = EAFNOSUPPORT;
798 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
799 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) {
803 bcopy(GET_V4(&sin6->sin6_addr), &addr, sizeof(addr));
804 if (isrfc1918addr(&addr)) {
809 ifa->ifa_rtrequest = stf_rtrequest;
810 ifp->if_flags |= IFF_UP;
815 ifr = (struct ifreq *)data;
816 if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
819 error = EAFNOSUPPORT;