The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/net/if_stf.c

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    1 /*      $NetBSD: if_stf.c,v 1.54 2006/11/16 01:33:40 christos 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 1.54 2006/11/16 01:33:40 christos 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 <sys/kauth.h>
   94 
   95 #include <machine/cpu.h>
   96 
   97 #include <net/if.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_gif.h>
  112 #include <netinet6/in6_var.h>
  113 #include <netinet/ip_ecn.h>
  114 
  115 #include <netinet/ip_encap.h>
  116 
  117 #include <machine/stdarg.h>
  118 
  119 #include <net/net_osdep.h>
  120 
  121 #include "bpfilter.h"
  122 #include "stf.h"
  123 #include "gif.h"        /*XXX*/
  124 
  125 #if NBPFILTER > 0
  126 #include <net/bpf.h>
  127 #endif
  128 
  129 #if NGIF > 0
  130 #include <net/if_gif.h>
  131 #endif
  132 
  133 #define IN6_IS_ADDR_6TO4(x)     (ntohs((x)->s6_addr16[0]) == 0x2002)
  134 #define GET_V4(x)       ((struct in_addr *)(&(x)->s6_addr16[1]))
  135 
  136 struct stf_softc {
  137         struct ifnet    sc_if;     /* common area */
  138         union {
  139                 struct route  __sc_ro4;
  140                 struct route_in6 __sc_ro6; /* just for safety */
  141         } __sc_ro46;
  142 #define sc_ro   __sc_ro46.__sc_ro4
  143         const struct encaptab *encap_cookie;
  144         LIST_ENTRY(stf_softc) sc_list;
  145 };
  146 
  147 static LIST_HEAD(, stf_softc) stf_softc_list;
  148 
  149 static int      stf_clone_create(struct if_clone *, int);
  150 static int      stf_clone_destroy(struct ifnet *);
  151 
  152 struct if_clone stf_cloner =
  153     IF_CLONE_INITIALIZER("stf", stf_clone_create, stf_clone_destroy);
  154 
  155 #if NGIF > 0
  156 extern int ip_gif_ttl;  /*XXX*/
  157 #else
  158 static int ip_gif_ttl = 40;     /*XXX*/
  159 #endif
  160 
  161 extern struct domain inetdomain;
  162 static const struct protosw in_stf_protosw =
  163 { SOCK_RAW,     &inetdomain,    IPPROTO_IPV6,   PR_ATOMIC|PR_ADDR,
  164   in_stf_input, rip_output,     0,              rip_ctloutput,
  165   rip_usrreq,
  166   0,            0,              0,              0
  167 };
  168 
  169 void    stfattach(int);
  170 
  171 static int stf_encapcheck(struct mbuf *, int, int, void *);
  172 static struct in6_ifaddr *stf_getsrcifa6(struct ifnet *);
  173 static int stf_output(struct ifnet *, struct mbuf *, struct sockaddr *,
  174         struct rtentry *);
  175 static int isrfc1918addr(struct in_addr *);
  176 static int stf_checkaddr4(struct stf_softc *, struct in_addr *,
  177         struct ifnet *);
  178 static int stf_checkaddr6(struct stf_softc *, struct in6_addr *,
  179         struct ifnet *);
  180 static void stf_rtrequest(int, struct rtentry *, struct rt_addrinfo *);
  181 static int stf_ioctl(struct ifnet *, u_long, caddr_t);
  182 
  183 /* ARGSUSED */
  184 void
  185 stfattach(int count)
  186 {
  187 
  188         LIST_INIT(&stf_softc_list);
  189         if_clone_attach(&stf_cloner);
  190 }
  191 
  192 static int
  193 stf_clone_create(struct if_clone *ifc, int unit)
  194 {
  195         struct stf_softc *sc;
  196 
  197         if (LIST_FIRST(&stf_softc_list) != NULL) {
  198                 /* Only one stf interface is allowed. */
  199                 return (EEXIST);
  200         }
  201 
  202         sc = malloc(sizeof(struct stf_softc), M_DEVBUF, M_WAIT);
  203         memset(sc, 0, sizeof(struct stf_softc));
  204 
  205         snprintf(sc->sc_if.if_xname, sizeof(sc->sc_if.if_xname), "%s%d",
  206             ifc->ifc_name, unit);
  207 
  208         sc->encap_cookie = encap_attach_func(AF_INET, IPPROTO_IPV6,
  209             stf_encapcheck, &in_stf_protosw, sc);
  210         if (sc->encap_cookie == NULL) {
  211                 printf("%s: unable to attach encap\n", if_name(&sc->sc_if));
  212                 free(sc, M_DEVBUF);
  213                 return (EIO);   /* XXX */
  214         }
  215 
  216         sc->sc_if.if_mtu    = STF_MTU;
  217         sc->sc_if.if_flags  = 0;
  218         sc->sc_if.if_ioctl  = stf_ioctl;
  219         sc->sc_if.if_output = stf_output;
  220         sc->sc_if.if_type   = IFT_STF;
  221         sc->sc_if.if_dlt    = DLT_NULL;
  222         if_attach(&sc->sc_if);
  223         if_alloc_sadl(&sc->sc_if);
  224 #if NBPFILTER > 0
  225         bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
  226 #endif
  227         LIST_INSERT_HEAD(&stf_softc_list, sc, sc_list);
  228         return (0);
  229 }
  230 
  231 static int
  232 stf_clone_destroy(struct ifnet *ifp)
  233 {
  234         struct stf_softc *sc = (void *) ifp;
  235 
  236         LIST_REMOVE(sc, sc_list);
  237         encap_detach(sc->encap_cookie);
  238 #if NBPFILTER > 0
  239         bpfdetach(ifp);
  240 #endif
  241         if_detach(ifp);
  242         free(sc, M_DEVBUF);
  243 
  244         return (0);
  245 }
  246 
  247 static int
  248 stf_encapcheck(struct mbuf *m, int off, int proto, void *arg)
  249 {
  250         struct ip ip;
  251         struct in6_ifaddr *ia6;
  252         struct stf_softc *sc;
  253         struct in_addr a, b;
  254 
  255         sc = (struct stf_softc *)arg;
  256         if (sc == NULL)
  257                 return 0;
  258 
  259         if ((sc->sc_if.if_flags & IFF_UP) == 0)
  260                 return 0;
  261 
  262         /* IFF_LINK0 means "no decapsulation" */
  263         if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
  264                 return 0;
  265 
  266         if (proto != IPPROTO_IPV6)
  267                 return 0;
  268 
  269         m_copydata(m, 0, sizeof(ip), (caddr_t)&ip);
  270 
  271         if (ip.ip_v != 4)
  272                 return 0;
  273 
  274         ia6 = stf_getsrcifa6(&sc->sc_if);
  275         if (ia6 == NULL)
  276                 return 0;
  277 
  278         /*
  279          * check if IPv4 dst matches the IPv4 address derived from the
  280          * local 6to4 address.
  281          * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
  282          */
  283         if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
  284             sizeof(ip.ip_dst)) != 0)
  285                 return 0;
  286 
  287         /*
  288          * check if IPv4 src matches the IPv4 address derived from the
  289          * local 6to4 address masked by prefixmask.
  290          * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
  291          * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
  292          */
  293         memset(&a, 0, sizeof(a));
  294         a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
  295         a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
  296         b = ip.ip_src;
  297         b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
  298         if (a.s_addr != b.s_addr)
  299                 return 0;
  300 
  301         /* stf interface makes single side match only */
  302         return 32;
  303 }
  304 
  305 static struct in6_ifaddr *
  306 stf_getsrcifa6(struct ifnet *ifp)
  307 {
  308         struct ifaddr *ifa;
  309         struct in_ifaddr *ia4;
  310         struct sockaddr_in6 *sin6;
  311         struct in_addr in;
  312 
  313         IFADDR_FOREACH(ifa, ifp)
  314         {
  315                 if (ifa->ifa_addr == NULL)
  316                         continue;
  317                 if (ifa->ifa_addr->sa_family != AF_INET6)
  318                         continue;
  319                 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
  320                 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
  321                         continue;
  322 
  323                 bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
  324                 INADDR_TO_IA(in, ia4);
  325                 if (ia4 == NULL)
  326                         continue;
  327 
  328                 return (struct in6_ifaddr *)ifa;
  329         }
  330 
  331         return NULL;
  332 }
  333 
  334 static int
  335 stf_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
  336     struct rtentry *rt)
  337 {
  338         struct stf_softc *sc;
  339         struct sockaddr_in6 *dst6;
  340         struct in_addr *in4;
  341         struct sockaddr_in *dst4;
  342         u_int8_t tos;
  343         struct ip *ip;
  344         struct ip6_hdr *ip6;
  345         struct in6_ifaddr *ia6;
  346 
  347         sc = (struct stf_softc*)ifp;
  348         dst6 = (struct sockaddr_in6 *)dst;
  349 
  350         /* just in case */
  351         if ((ifp->if_flags & IFF_UP) == 0) {
  352                 m_freem(m);
  353                 return ENETDOWN;
  354         }
  355 
  356         /*
  357          * If we don't have an ip4 address that match my inner ip6 address,
  358          * we shouldn't generate output.  Without this check, we'll end up
  359          * using wrong IPv4 source.
  360          */
  361         ia6 = stf_getsrcifa6(ifp);
  362         if (ia6 == NULL) {
  363                 m_freem(m);
  364                 ifp->if_oerrors++;
  365                 return ENETDOWN;
  366         }
  367 
  368         if (m->m_len < sizeof(*ip6)) {
  369                 m = m_pullup(m, sizeof(*ip6));
  370                 if (m == NULL) {
  371                         ifp->if_oerrors++;
  372                         return ENOBUFS;
  373                 }
  374         }
  375         ip6 = mtod(m, struct ip6_hdr *);
  376         tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  377 
  378         /*
  379          * Pickup the right outer dst addr from the list of candidates.
  380          * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
  381          */
  382         if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
  383                 in4 = GET_V4(&ip6->ip6_dst);
  384         else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
  385                 in4 = GET_V4(&dst6->sin6_addr);
  386         else {
  387                 m_freem(m);
  388                 ifp->if_oerrors++;
  389                 return ENETUNREACH;
  390         }
  391 
  392 #if NBPFILTER > 0
  393         if (ifp->if_bpf)
  394                 bpf_mtap_af(ifp->if_bpf, AF_INET6, m);
  395 #endif /*NBPFILTER > 0*/
  396 
  397         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
  398         if (m && m->m_len < sizeof(struct ip))
  399                 m = m_pullup(m, sizeof(struct ip));
  400         if (m == NULL) {
  401                 ifp->if_oerrors++;
  402                 return ENOBUFS;
  403         }
  404         ip = mtod(m, struct ip *);
  405 
  406         memset(ip, 0, sizeof(*ip));
  407 
  408         bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
  409             &ip->ip_src, sizeof(ip->ip_src));
  410         bcopy(in4, &ip->ip_dst, sizeof(ip->ip_dst));
  411         ip->ip_p = IPPROTO_IPV6;
  412         ip->ip_ttl = ip_gif_ttl;        /*XXX*/
  413         ip->ip_len = htons(m->m_pkthdr.len);
  414         if (ifp->if_flags & IFF_LINK1)
  415                 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
  416         else
  417                 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
  418 
  419         dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
  420         if (dst4->sin_family != AF_INET ||
  421             bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
  422                 /* cache route doesn't match */
  423                 dst4->sin_family = AF_INET;
  424                 dst4->sin_len = sizeof(struct sockaddr_in);
  425                 bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
  426                 if (sc->sc_ro.ro_rt) {
  427                         RTFREE(sc->sc_ro.ro_rt);
  428                         sc->sc_ro.ro_rt = NULL;
  429                 }
  430         }
  431 
  432         if (sc->sc_ro.ro_rt == NULL) {
  433                 rtalloc(&sc->sc_ro);
  434                 if (sc->sc_ro.ro_rt == NULL) {
  435                         m_freem(m);
  436                         ifp->if_oerrors++;
  437                         return ENETUNREACH;
  438                 }
  439         }
  440 
  441         ifp->if_opackets++;
  442         return ip_output(m, NULL, &sc->sc_ro, 0,
  443             (struct ip_moptions *)NULL, (struct socket *)NULL);
  444 }
  445 
  446 static int
  447 isrfc1918addr(struct in_addr *in)
  448 {
  449         /*
  450          * returns 1 if private address range:
  451          * 10.0.0.0/8 172.16.0.0/12 192.168.0.0/16
  452          */
  453         if ((ntohl(in->s_addr) & 0xff000000) >> 24 == 10 ||
  454             (ntohl(in->s_addr) & 0xfff00000) >> 16 == 172 * 256 + 16 ||
  455             (ntohl(in->s_addr) & 0xffff0000) >> 16 == 192 * 256 + 168)
  456                 return 1;
  457 
  458         return 0;
  459 }
  460 
  461 static int
  462 stf_checkaddr4(struct stf_softc *sc, struct in_addr *in,
  463     struct ifnet *inifp /*incoming interface*/)
  464 {
  465         struct in_ifaddr *ia4;
  466 
  467         /*
  468          * reject packets with the following address:
  469          * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
  470          */
  471         if (IN_MULTICAST(in->s_addr))
  472                 return -1;
  473         switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
  474         case 0: case 127: case 255:
  475                 return -1;
  476         }
  477 
  478         /*
  479          * reject packets with private address range.
  480          * (requirement from RFC3056 section 2 1st paragraph)
  481          */
  482         if (isrfc1918addr(in))
  483                 return -1;
  484 
  485         /*
  486          * reject packet with IPv4 link-local (169.254.0.0/16),
  487          * as suggested in draft-savola-v6ops-6to4-security-00.txt
  488          */
  489         if (((ntohl(in->s_addr) & 0xff000000) >> 24) == 169 &&
  490             ((ntohl(in->s_addr) & 0x00ff0000) >> 16) == 254)
  491                 return -1;
  492 
  493         /*
  494          * reject packets with broadcast
  495          */
  496         TAILQ_FOREACH(ia4, &in_ifaddrhead, ia_list)
  497         {
  498                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
  499                         continue;
  500                 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
  501                         return -1;
  502         }
  503 
  504         /*
  505          * perform ingress filter
  506          */
  507         if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
  508                 struct sockaddr_in sin;
  509                 struct rtentry *rt;
  510 
  511                 memset(&sin, 0, sizeof(sin));
  512                 sin.sin_family = AF_INET;
  513                 sin.sin_len = sizeof(struct sockaddr_in);
  514                 sin.sin_addr = *in;
  515                 rt = rtalloc1((struct sockaddr *)&sin, 0);
  516                 if (!rt || rt->rt_ifp != inifp) {
  517 #if 0
  518                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
  519                             "due to ingress filter\n", if_name(&sc->sc_if),
  520                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
  521 #endif
  522                         if (rt)
  523                                 rtfree(rt);
  524                         return -1;
  525                 }
  526                 rtfree(rt);
  527         }
  528 
  529         return 0;
  530 }
  531 
  532 static int
  533 stf_checkaddr6(struct stf_softc *sc, struct in6_addr *in6,
  534     struct ifnet *inifp /*incoming interface*/)
  535 {
  536 
  537         /*
  538          * check 6to4 addresses
  539          */
  540         if (IN6_IS_ADDR_6TO4(in6))
  541                 return stf_checkaddr4(sc, GET_V4(in6), inifp);
  542 
  543         /*
  544          * reject anything that look suspicious.  the test is implemented
  545          * in ip6_input too, but we check here as well to
  546          * (1) reject bad packets earlier, and
  547          * (2) to be safe against future ip6_input change.
  548          */
  549         if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
  550                 return -1;
  551 
  552         /*
  553          * reject link-local and site-local unicast
  554          * as suggested in draft-savola-v6ops-6to4-security-00.txt
  555          */
  556         if (IN6_IS_ADDR_LINKLOCAL(in6) || IN6_IS_ADDR_SITELOCAL(in6))
  557                 return -1;
  558 
  559         /*
  560          * reject node-local and link-local multicast
  561          * as suggested in draft-savola-v6ops-6to4-security-00.txt
  562          */
  563         if (IN6_IS_ADDR_MC_NODELOCAL(in6) || IN6_IS_ADDR_MC_LINKLOCAL(in6))
  564                 return -1;
  565 
  566         return 0;
  567 }
  568 
  569 void
  570 in_stf_input(struct mbuf *m, ...)
  571 {
  572         int off, proto;
  573         struct stf_softc *sc;
  574         struct ip *ip;
  575         struct ip6_hdr *ip6;
  576         u_int8_t otos, itos;
  577         int s, isr;
  578         struct ifqueue *ifq = NULL;
  579         struct ifnet *ifp;
  580         va_list ap;
  581 
  582         va_start(ap, m);
  583         off = va_arg(ap, int);
  584         proto = va_arg(ap, int);
  585         va_end(ap);
  586 
  587         if (proto != IPPROTO_IPV6) {
  588                 m_freem(m);
  589                 return;
  590         }
  591 
  592         ip = mtod(m, struct ip *);
  593 
  594         sc = (struct stf_softc *)encap_getarg(m);
  595 
  596         if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) {
  597                 m_freem(m);
  598                 return;
  599         }
  600 
  601         ifp = &sc->sc_if;
  602 
  603         /*
  604          * perform sanity check against outer src/dst.
  605          * for source, perform ingress filter as well.
  606          */
  607         if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
  608             stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
  609                 m_freem(m);
  610                 return;
  611         }
  612 
  613         otos = ip->ip_tos;
  614         m_adj(m, off);
  615 
  616         if (m->m_len < sizeof(*ip6)) {
  617                 m = m_pullup(m, sizeof(*ip6));
  618                 if (!m)
  619                         return;
  620         }
  621         ip6 = mtod(m, struct ip6_hdr *);
  622 
  623         /*
  624          * perform sanity check against inner src/dst.
  625          * for source, perform ingress filter as well.
  626          */
  627         if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
  628             stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
  629                 m_freem(m);
  630                 return;
  631         }
  632 
  633         itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
  634         if ((ifp->if_flags & IFF_LINK1) != 0)
  635                 ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
  636         else
  637                 ip_ecn_egress(ECN_NOCARE, &otos, &itos);
  638         ip6->ip6_flow &= ~htonl(0xff << 20);
  639         ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
  640 
  641         m->m_pkthdr.rcvif = ifp;
  642 
  643 #if NBPFILTER > 0
  644         if (ifp->if_bpf)
  645                 bpf_mtap_af(ifp->if_bpf, AF_INET6, m);
  646 #endif /*NBPFILTER > 0*/
  647 
  648         /*
  649          * Put the packet to the network layer input queue according to the
  650          * specified address family.
  651          * See net/if_gif.c for possible issues with packet processing
  652          * reorder due to extra queueing.
  653          */
  654         ifq = &ip6intrq;
  655         isr = NETISR_IPV6;
  656 
  657         s = splnet();
  658         if (IF_QFULL(ifq)) {
  659                 IF_DROP(ifq);   /* update statistics */
  660                 m_freem(m);
  661                 splx(s);
  662                 return;
  663         }
  664         IF_ENQUEUE(ifq, m);
  665         schednetisr(isr);
  666         ifp->if_ipackets++;
  667         ifp->if_ibytes += m->m_pkthdr.len;
  668         splx(s);
  669 }
  670 
  671 /* ARGSUSED */
  672 static void
  673 stf_rtrequest(int cmd, struct rtentry *rt,
  674     struct rt_addrinfo *info)
  675 {
  676         if (rt != NULL) {
  677                 struct stf_softc *sc;
  678 
  679                 sc = LIST_FIRST(&stf_softc_list);
  680                 rt->rt_rmx.rmx_mtu = (sc != NULL) ? sc->sc_if.if_mtu : STF_MTU;
  681         }
  682 }
  683 
  684 static int
  685 stf_ioctl(struct ifnet *ifp, u_long cmd, caddr_t data)
  686 {
  687         struct lwp              *l = curlwp;    /* XXX */
  688         struct ifaddr           *ifa;
  689         struct ifreq            *ifr;
  690         struct sockaddr_in6     *sin6;
  691         int                     error;
  692         u_long                  mtu;
  693 
  694         error = 0;
  695         switch (cmd) {
  696         case SIOCSIFADDR:
  697                 ifa = (struct ifaddr *)data;
  698                 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
  699                         error = EAFNOSUPPORT;
  700                         break;
  701                 }
  702                 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
  703                 if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr) &&
  704                     !isrfc1918addr(GET_V4(&sin6->sin6_addr))) {
  705                         ifa->ifa_rtrequest = stf_rtrequest;
  706                         ifp->if_flags |= IFF_UP;
  707                 } else
  708                         error = EINVAL;
  709                 break;
  710 
  711         case SIOCADDMULTI:
  712         case SIOCDELMULTI:
  713                 ifr = (struct ifreq *)data;
  714                 if (ifr != NULL && ifr->ifr_addr.sa_family == AF_INET6)
  715                         ;
  716                 else
  717                         error = EAFNOSUPPORT;
  718                 break;
  719 
  720         case SIOCSIFMTU:
  721                 if ((error = kauth_authorize_generic(l->l_cred,
  722                     KAUTH_GENERIC_ISSUSER, &l->l_acflag)) != 0)
  723                         break;
  724                 ifr = (struct ifreq *)data;
  725                 mtu = ifr->ifr_mtu;
  726                 if (mtu < STF_MTU_MIN || mtu > STF_MTU_MAX)
  727                         return EINVAL;
  728                 ifp->if_mtu = mtu;
  729                 break;
  730 
  731         default:
  732                 error = EINVAL;
  733                 break;
  734         }
  735 
  736         return error;
  737 }

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