bsd/net/if_stf.c

   1 /*      $FreeBSD: src/sys/net/if_stf.c,v 1.1.2.6 2001/07/24 19:10:18 brooks 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/param.h>
  78 #include <sys/systm.h>
  79 #include <sys/socket.h>
  80 #include <sys/sockio.h>
  81 #include <sys/mbuf.h>
  82 #include <sys/errno.h>
  83 #include <sys/protosw.h>
  84 #include <sys/kernel.h>
  85 #include <sys/syslog.h>
  86 #include <machine/cpu.h>
  87
  88 #include <sys/malloc.h>
  89
  90 #include <net/if.h>
  91 #include <net/route.h>
  92 #include <net/netisr.h>
  93 #include <net/if_types.h>
  94 #include <net/if_stf.h>
  95
  96 #include <netinet/in.h>
  97 #include <netinet/in_systm.h>
  98 #include <netinet/ip.h>
  99 #include <netinet/ip_var.h>
 100 #include <netinet/in_var.h>
 101
 102 #include <netinet/ip6.h>
 103 #include <netinet6/ip6_var.h>
 104 #include <netinet6/in6_var.h>
 105 #include <netinet/ip_ecn.h>
 106
 107 #include <netinet/ip_encap.h>
 108 #include <net/dlil.h>
 109
 110
 111 #include <net/net_osdep.h>
 112
 113 #include <net/bpf.h>
 114
 115 #define IN6_IS_ADDR_6TO4(x)     (ntohs((x)->s6_addr16[0]) == 0x2002)
 116 #define GET_V4(x)       ((struct in_addr *)(&(x)->s6_addr16[1]))
 117
 118 struct stf_softc {
 119         struct ifnet    sc_if;     /* common area */
 120 #ifdef __APPLE__
 121         struct if_proto *stf_proto; /* dlil protocol attached */
 122 #endif
 123         union {
 124                 struct route  __sc_ro4;
 125                 struct route_in6 __sc_ro6; /* just for safety */
 126         } __sc_ro46;
 127 #define sc_ro   __sc_ro46.__sc_ro4
 128         const struct encaptab *encap_cookie;
 129 };
 130
 131 static struct stf_softc *stf;
 132
 133 #ifdef __APPLE__
 134 void stfattach __P((void));
 135 int stf_pre_output __P((struct ifnet *, register struct mbuf **, struct sockaddr *,
 136         caddr_t, char *, char *, u_long));
 137 static u_long stf_dl_tag=0;
 138 #endif
 139
 140 #ifndef __APPLE__
 141 static MALLOC_DEFINE(M_STF, "stf", "6to4 Tunnel Interface");
 142 #endif
 143 static int ip_stf_ttl = 40;
 144
 145 extern  struct domain inetdomain;
 146 struct protosw in_stf_protosw =
 147 { SOCK_RAW,     &inetdomain,    IPPROTO_IPV6,   PR_ATOMIC|PR_ADDR,
 148   in_stf_input, 0,      0,              rip_ctloutput,
 149   0,
 150   0,            0,              0,              0,
 151   0,
 152   &rip_usrreqs
 153 };
 154
 155 static int stf_encapcheck __P((const struct mbuf *, int, int, void *));
 156 static struct in6_ifaddr *stf_getsrcifa6 __P((struct ifnet *));
 157 int stf_pre_output __P((struct ifnet *, register struct mbuf **, struct sockaddr *,
 158         caddr_t, char *, char *, u_long));
 159 static int stf_checkaddr4 __P((struct stf_softc *, struct in_addr *,
 160         struct ifnet *));
 161 static int stf_checkaddr6 __P((struct stf_softc *, struct in6_addr *,
 162         struct ifnet *));
 163 static void stf_rtrequest __P((int, struct rtentry *, struct sockaddr *));
 164 int stf_ioctl __P((struct ifnet *, u_long, void *));
 165
 166
 167 static
 168 int  stf_add_if(struct ifnet *ifp)
 169 {
 170     ifp->if_demux  = 0;
 171     ifp->if_framer = 0;
 172     return 0;
 173 }
 174
 175 static
 176 int  stf_del_if(struct ifnet *ifp)
 177 {
 178     return 0;
 179 }
 180
 181 static
 182 int  stf_add_proto(struct ddesc_head_str *desc_head, struct if_proto *proto, u_long dl_tag)
 183 {
 184         /* Only one protocol may be attached at a time */
 185         struct stf_softc* stf = (struct stf_softc*)proto->ifp;
 186         if (stf->stf_proto == NULL)
 187                 stf->stf_proto = proto;
 188         else {
 189                 printf("stf_add_proto: stf already has a proto\n");
 190                 return (EBUSY);
 191         }
 192
 193         return (0);
 194 }
 195
 196 static
 197 int  stf_del_proto(struct if_proto *proto, u_long dl_tag)
 198 {
 199         if (((struct stf_softc*)proto->ifp)->stf_proto == proto)
 200                 ((struct stf_softc*)proto->ifp)->stf_proto = NULL;
 201         else
 202                 return ENOENT;
 203
 204         return 0;
 205 }
 206
 207 int stf_shutdown()
 208 {
 209         return 0;
 210 }
 211
 212 int  stf_attach_inet6(struct ifnet *ifp, u_long *dl_tag)
 213 {
 214     struct dlil_proto_reg_str   reg;
 215     struct dlil_demux_desc      desc;
 216     short native=0;
 217     int   stat, i;
 218
 219     if (stf_dl_tag != 0) {
 220                 *dl_tag = stf_dl_tag;
 221                 return 0;
 222     }
 223
 224     TAILQ_INIT(&reg.demux_desc_head);
 225     desc.type = DLIL_DESC_RAW;
 226     desc.variants.bitmask.proto_id_length = 0;
 227     desc.variants.bitmask.proto_id = 0;
 228     desc.variants.bitmask.proto_id_mask = 0;
 229     desc.native_type = (char *) &native;
 230     TAILQ_INSERT_TAIL(&reg.demux_desc_head, &desc, next);
 231     reg.interface_family = ifp->if_family;
 232     reg.unit_number      = ifp->if_unit;
 233     reg.input            = 0;
 234     reg.pre_output       = stf_pre_output;
 235     reg.event            = 0;
 236     reg.offer            = 0;
 237     reg.ioctl            = 0;
 238     reg.default_proto    = 0;
 239     reg.protocol_family  = PF_INET6;
 240
 241     stat = dlil_attach_protocol(&reg, &stf_dl_tag);
 242     *dl_tag = stf_dl_tag;
 243
 244     return stat;
 245 }
 246
 247 int  stf_detach_inet6(struct ifnet *ifp, u_long dl_tag)
 248 {
 249     int         stat;
 250
 251     stat = dlil_find_dltag(ifp->if_family, ifp->if_unit, AF_INET6, &dl_tag);
 252     if (stat == 0) {
 253         stat = dlil_detach_protocol(dl_tag);
 254         if (stat) {
 255             printf("WARNING: stf_detach can't detach IP AF_INET6 from interface\n");
 256         }
 257     }
 258     return (stat);
 259 }
 260
 261 void stf_reg_if_mods()
 262 {
 263         struct dlil_ifmod_reg_str  stf_ifmod;
 264         struct dlil_protomod_reg_str stf_protoreg;
 265         int error;
 266
 267         bzero(&stf_ifmod, sizeof(stf_ifmod));
 268         stf_ifmod.add_if        = stf_add_if;
 269         stf_ifmod.del_if        = stf_del_if;
 270         stf_ifmod.add_proto = stf_add_proto;
 271         stf_ifmod.del_proto = stf_del_proto;
 272         stf_ifmod.ifmod_ioctl = 0;
 273         stf_ifmod.shutdown    = stf_shutdown;
 274
 275
 276         if (dlil_reg_if_modules(APPLE_IF_FAM_STF, &stf_ifmod))
 277         panic("Couldn't register stf modules\n");
 278
 279         /* Register protocol registration functions */
 280
 281         bzero(&stf_protoreg, sizeof(stf_protoreg));
 282         stf_protoreg.attach_proto = stf_attach_inet6;
 283         stf_protoreg.detach_proto = stf_detach_inet6;
 284
 285         if ( error = dlil_reg_proto_module(AF_INET6, APPLE_IF_FAM_STF, &stf_protoreg) != 0)
 286                 kprintf("dlil_reg_proto_module failed for AF_INET6 error=%d\n", error);
 287 }
 288
 289 void
 290 stfattach(void)
 291 {
 292         struct ifnet *ifp;
 293         struct stf_softc *sc;
 294         int i, error;
 295
 296
 297         int err;
 298         const struct encaptab *p;
 299
 300         stf_reg_if_mods(); /* DLIL modules */
 301
 302         sc = _MALLOC(sizeof(struct stf_softc), M_DEVBUF, M_WAITOK);
 303         if (sc == 0) {
 304                 printf("stf softc attach failed\n" );
 305                 return;
 306         }
 307
 308         bzero(sc, sizeof(*sc));
 309         sc->sc_if.if_name = "stf";
 310         sc->sc_if.if_unit = 0;
 311
 312         p = encap_attach_func(AF_INET, IPPROTO_IPV6, stf_encapcheck,
 313             &in_stf_protosw, sc);
 314         if (p == NULL) {
 315                 printf("%s: attach failed\n", if_name(&sc->sc_if));
 316                 FREE(sc, M_DEVBUF);
 317                 return;
 318         }
 319         sc->encap_cookie = p;
 320         sc->sc_if.if_mtu    = IPV6_MMTU;
 321         sc->sc_if.if_flags  = 0;
 322         sc->sc_if.if_ioctl  = stf_ioctl;
 323         sc->sc_if.if_output = NULL; /* processing done in pre_output */
 324         sc->sc_if.if_type   = IFT_STF;
 325         sc->sc_if.if_family= APPLE_IF_FAM_STF;
 326 #if 0
 327         /* turn off ingress filter */
 328         sc->sc_if.if_flags  |= IFF_LINK2;
 329 #endif
 330         sc->sc_if.if_snd.ifq_maxlen = IFQ_MAXLEN;
 331
 332         if (error = dlil_if_attach(&sc->sc_if))
 333                 printf("stfattach: can't dlil_if_attach error=%d\n");
 334         else
 335                 bpfattach(&sc->sc_if, DLT_NULL, sizeof(u_int));
 336
 337         return ;
 338 }
 339
 340 static int
 341 stf_encapcheck(m, off, proto, arg)
 342         const struct mbuf *m;
 343         int off;
 344         int proto;
 345         void *arg;
 346 {
 347         struct ip ip;
 348         struct in6_ifaddr *ia6;
 349         struct stf_softc *sc;
 350         struct in_addr a, b;
 351
 352         sc = (struct stf_softc *)arg;
 353         if (sc == NULL)
 354                 return 0;
 355
 356         if ((sc->sc_if.if_flags & IFF_UP) == 0)
 357                 return 0;
 358
 359         /* IFF_LINK0 means "no decapsulation" */
 360         if ((sc->sc_if.if_flags & IFF_LINK0) != 0)
 361                 return 0;
 362
 363         if (proto != IPPROTO_IPV6)
 364                 return 0;
 365
 366         /* LINTED const cast */
 367         m_copydata((struct mbuf *)m, 0, sizeof(ip), (caddr_t)&ip);
 368
 369         if (ip.ip_v != 4)
 370                 return 0;
 371
 372         ia6 = stf_getsrcifa6(&sc->sc_if);
 373         if (ia6 == NULL)
 374                 return 0;
 375
 376         /*
 377          * check if IPv4 dst matches the IPv4 address derived from the
 378          * local 6to4 address.
 379          * success on: dst = 10.1.1.1, ia6->ia_addr = 2002:0a01:0101:...
 380          */
 381         if (bcmp(GET_V4(&ia6->ia_addr.sin6_addr), &ip.ip_dst,
 382             sizeof(ip.ip_dst)) != 0)
 383                 return 0;
 384
 385         /*
 386          * check if IPv4 src matches the IPv4 address derived from the
 387          * local 6to4 address masked by prefixmask.
 388          * success on: src = 10.1.1.1, ia6->ia_addr = 2002:0a00:.../24
 389          * fail on: src = 10.1.1.1, ia6->ia_addr = 2002:0b00:.../24
 390          */
 391         bzero(&a, sizeof(a));
 392         a.s_addr = GET_V4(&ia6->ia_addr.sin6_addr)->s_addr;
 393         a.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
 394         b = ip.ip_src;
 395         b.s_addr &= GET_V4(&ia6->ia_prefixmask.sin6_addr)->s_addr;
 396         if (a.s_addr != b.s_addr)
 397                 return 0;
 398
 399         /* stf interface makes single side match only */
 400         return 32;
 401 }
 402
 403 static struct in6_ifaddr *
 404 stf_getsrcifa6(ifp)
 405         struct ifnet *ifp;
 406 {
 407         struct ifaddr *ia;
 408         struct in_ifaddr *ia4;
 409         struct sockaddr_in6 *sin6;
 410         struct in_addr in;
 411
 412         for (ia = ifp->if_addrlist.tqh_first;
 413              ia;
 414              ia = ia->ifa_list.tqe_next)
 415         {
 416                 if (ia->ifa_addr == NULL)
 417                         continue;
 418                 if (ia->ifa_addr->sa_family != AF_INET6)
 419                         continue;
 420                 sin6 = (struct sockaddr_in6 *)ia->ifa_addr;
 421                 if (!IN6_IS_ADDR_6TO4(&sin6->sin6_addr))
 422                         continue;
 423
 424                 bcopy(GET_V4(&sin6->sin6_addr), &in, sizeof(in));
 425                 for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
 426                      ia4;
 427                      ia4 = TAILQ_NEXT(ia4, ia_link))
 428                 {
 429                         if (ia4->ia_addr.sin_addr.s_addr == in.s_addr)
 430                                 break;
 431                 }
 432                 if (ia4 == NULL)
 433                         continue;
 434
 435                 return (struct in6_ifaddr *)ia;
 436         }
 437
 438         return NULL;
 439 }
 440
 441 int
 442 stf_pre_output(ifp, m0, dst, rt, frame_type, address, dl_tag)
 443         struct ifnet *ifp;
 444         register struct mbuf **m0;
 445         struct sockaddr *dst;
 446         caddr_t                 rt;
 447         char                 *frame_type;
 448         char                 *address;
 449         u_long               dl_tag;
 450 {
 451         register struct mbuf *m = *m0;
 452         struct stf_softc *sc;
 453         struct sockaddr_in6 *dst6;
 454         struct in_addr *in4;
 455         struct sockaddr_in *dst4;
 456         u_int8_t tos;
 457         struct ip *ip;
 458         struct ip6_hdr *ip6;
 459         struct in6_ifaddr *ia6;
 460         int error = 0 ;
 461
 462         sc = (struct stf_softc*)ifp;
 463         dst6 = (struct sockaddr_in6 *)dst;
 464
 465         /* just in case */
 466         if ((ifp->if_flags & IFF_UP) == 0) {
 467                 printf("stf: IFF_DOWN\n");
 468                 return ENETDOWN;
 469         }
 470
 471         /*
 472          * If we don't have an ip4 address that match my inner ip6 address,
 473          * we shouldn't generate output.  Without this check, we'll end up
 474          * using wrong IPv4 source.
 475          */
 476         ia6 = stf_getsrcifa6(ifp);
 477         if (ia6 == NULL) {
 478                 return ENETDOWN;
 479         }
 480
 481         if (m->m_len < sizeof(*ip6)) {
 482                 m = m_pullup(m, sizeof(*ip6));
 483                 if (!m)
 484                         return ENOBUFS;
 485         }
 486         ip6 = mtod(m, struct ip6_hdr *);
 487         tos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 488
 489         /*
 490          * Pickup the right outer dst addr from the list of candidates.
 491          * ip6_dst has priority as it may be able to give us shorter IPv4 hops.
 492          */
 493         if (IN6_IS_ADDR_6TO4(&ip6->ip6_dst))
 494                 in4 = GET_V4(&ip6->ip6_dst);
 495         else if (IN6_IS_ADDR_6TO4(&dst6->sin6_addr))
 496                 in4 = GET_V4(&dst6->sin6_addr);
 497         else {
 498                 return ENETUNREACH;
 499         }
 500
 501         if (ifp->if_bpf) {
 502                 /*
 503                  * We need to prepend the address family as
 504                  * a four byte field.  Cons up a dummy header
 505                  * to pacify bpf.  This is safe because bpf
 506                  * will only read from the mbuf (i.e., it won't
 507                  * try to free it or keep a pointer a to it).
 508                  */
 509                 struct mbuf m0;
 510                 u_int32_t af = AF_INET6;
 511
 512                 m0.m_next = m;
 513                 m0.m_len = 4;
 514                 m0.m_data = (char *)&af;
 515
 516                 bpf_mtap(ifp, &m0);
 517         }
 518
 519         M_PREPEND(m, sizeof(struct ip), M_DONTWAIT);
 520         if (m && m->m_len < sizeof(struct ip))
 521                 m = m_pullup(m, sizeof(struct ip));
 522         if (m == NULL)
 523                 return ENOBUFS;
 524         ip = mtod(m, struct ip *);
 525
 526         bzero(ip, sizeof(*ip));
 527
 528         bcopy(GET_V4(&((struct sockaddr_in6 *)&ia6->ia_addr)->sin6_addr),
 529             &ip->ip_src, sizeof(ip->ip_src));
 530         bcopy(in4, &ip->ip_dst, sizeof(ip->ip_dst));
 531         ip->ip_p = IPPROTO_IPV6;
 532         ip->ip_ttl = ip_stf_ttl;
 533         ip->ip_len = m->m_pkthdr.len;   /*host order*/
 534         if (ifp->if_flags & IFF_LINK1)
 535                 ip_ecn_ingress(ECN_ALLOWED, &ip->ip_tos, &tos);
 536         else
 537                 ip_ecn_ingress(ECN_NOCARE, &ip->ip_tos, &tos);
 538
 539         dst4 = (struct sockaddr_in *)&sc->sc_ro.ro_dst;
 540         if (dst4->sin_family != AF_INET ||
 541             bcmp(&dst4->sin_addr, &ip->ip_dst, sizeof(ip->ip_dst)) != 0) {
 542                 /* cache route doesn't match */
 543                 dst4->sin_family = AF_INET;
 544                 dst4->sin_len = sizeof(struct sockaddr_in);
 545                 bcopy(&ip->ip_dst, &dst4->sin_addr, sizeof(dst4->sin_addr));
 546                 if (sc->sc_ro.ro_rt) {
 547                         RTFREE(sc->sc_ro.ro_rt);
 548                         sc->sc_ro.ro_rt = NULL;
 549                 }
 550         }
 551
 552         if (sc->sc_ro.ro_rt == NULL) {
 553                 rtalloc(&sc->sc_ro);
 554                 if (sc->sc_ro.ro_rt == NULL) {
 555                         return ENETUNREACH;
 556                 }
 557         }
 558
 559         error = ip_output(m, NULL, &sc->sc_ro, 0, NULL);
 560         if (error == 0)
 561                 return EJUSTRETURN;
 562 }
 563
 564 static int
 565 stf_checkaddr4(sc, in, inifp)
 566         struct stf_softc *sc;
 567         struct in_addr *in;
 568         struct ifnet *inifp;    /* incoming interface */
 569 {
 570         struct in_ifaddr *ia4;
 571
 572         /*
 573          * reject packets with the following address:
 574          * 224.0.0.0/4 0.0.0.0/8 127.0.0.0/8 255.0.0.0/8
 575          */
 576         if (IN_MULTICAST(ntohl(in->s_addr)))
 577                 return -1;
 578         switch ((ntohl(in->s_addr) & 0xff000000) >> 24) {
 579         case 0: case 127: case 255:
 580                 return -1;
 581         }
 582
 583         /*
 584          * reject packets with broadcast
 585          */
 586         for (ia4 = TAILQ_FIRST(&in_ifaddrhead);
 587              ia4;
 588              ia4 = TAILQ_NEXT(ia4, ia_link))
 589         {
 590                 if ((ia4->ia_ifa.ifa_ifp->if_flags & IFF_BROADCAST) == 0)
 591                         continue;
 592                 if (in->s_addr == ia4->ia_broadaddr.sin_addr.s_addr)
 593                         return -1;
 594         }
 595
 596         /*
 597          * perform ingress filter
 598          */
 599         if (sc && (sc->sc_if.if_flags & IFF_LINK2) == 0 && inifp) {
 600                 struct sockaddr_in sin;
 601                 struct rtentry *rt;
 602
 603                 bzero(&sin, sizeof(sin));
 604                 sin.sin_family = AF_INET;
 605                 sin.sin_len = sizeof(struct sockaddr_in);
 606                 sin.sin_addr = *in;
 607                 rt = rtalloc1((struct sockaddr *)&sin, 0, 0UL);
 608                 if (!rt || rt->rt_ifp != inifp) {
 609 #if 1
 610                         log(LOG_WARNING, "%s: packet from 0x%x dropped "
 611                             "due to ingress filter\n", if_name(&sc->sc_if),
 612                             (u_int32_t)ntohl(sin.sin_addr.s_addr));
 613 #endif
 614                         if (rt)
 615                                 rtfree(rt);
 616                         return -1;
 617                 }
 618                 rtfree(rt);
 619         }
 620
 621         return 0;
 622 }
 623
 624 static int
 625 stf_checkaddr6(sc, in6, inifp)
 626         struct stf_softc *sc;
 627         struct in6_addr *in6;
 628         struct ifnet *inifp;    /* incoming interface */
 629 {
 630         /*
 631          * check 6to4 addresses
 632          */
 633         if (IN6_IS_ADDR_6TO4(in6))
 634                 return stf_checkaddr4(sc, GET_V4(in6), inifp);
 635
 636         /*
 637          * reject anything that look suspicious.  the test is implemented
 638          * in ip6_input too, but we check here as well to
 639          * (1) reject bad packets earlier, and
 640          * (2) to be safe against future ip6_input change.
 641          */
 642         if (IN6_IS_ADDR_V4COMPAT(in6) || IN6_IS_ADDR_V4MAPPED(in6))
 643                 return -1;
 644
 645         return 0;
 646 }
 647
 648 void
 649 in_stf_input(m, off)
 650         struct mbuf *m;
 651         int off;
 652 {
 653         struct stf_softc *sc;
 654         struct ip *ip;
 655         struct ip6_hdr *ip6;
 656         u_int8_t otos, itos;
 657         int s, isr, proto;
 658         struct ifqueue *ifq = NULL;
 659         struct ifnet *ifp;
 660
 661         ip = mtod(m, struct ip *);
 662         proto = ip->ip_p;
 663
 664
 665         if (proto != IPPROTO_IPV6) {
 666                 m_freem(m);
 667                 return;
 668         }
 669
 670         ip = mtod(m, struct ip *);
 671
 672         sc = (struct stf_softc *)encap_getarg(m);
 673
 674         if (sc == NULL || (sc->sc_if.if_flags & IFF_UP) == 0) {
 675                 m_freem(m);
 676                 return;
 677         }
 678
 679         ifp = &sc->sc_if;
 680
 681         /*
 682          * perform sanity check against outer src/dst.
 683          * for source, perform ingress filter as well.
 684          */
 685         if (stf_checkaddr4(sc, &ip->ip_dst, NULL) < 0 ||
 686             stf_checkaddr4(sc, &ip->ip_src, m->m_pkthdr.rcvif) < 0) {
 687                 m_freem(m);
 688                 return;
 689         }
 690
 691         otos = ip->ip_tos;
 692         m_adj(m, off);
 693
 694         if (m->m_len < sizeof(*ip6)) {
 695                 m = m_pullup(m, sizeof(*ip6));
 696                 if (!m)
 697                         return;
 698         }
 699         ip6 = mtod(m, struct ip6_hdr *);
 700
 701         /*
 702          * perform sanity check against inner src/dst.
 703          * for source, perform ingress filter as well.
 704          */
 705         if (stf_checkaddr6(sc, &ip6->ip6_dst, NULL) < 0 ||
 706             stf_checkaddr6(sc, &ip6->ip6_src, m->m_pkthdr.rcvif) < 0) {
 707                 m_freem(m);
 708                 return;
 709         }
 710
 711         itos = (ntohl(ip6->ip6_flow) >> 20) & 0xff;
 712         if ((ifp->if_flags & IFF_LINK1) != 0)
 713                 ip_ecn_egress(ECN_ALLOWED, &otos, &itos);
 714         else
 715                 ip_ecn_egress(ECN_NOCARE, &otos, &itos);
 716         ip6->ip6_flow &= ~htonl(0xff << 20);
 717         ip6->ip6_flow |= htonl((u_int32_t)itos << 20);
 718
 719         m->m_pkthdr.rcvif = ifp;
 720
 721         if (ifp->if_bpf) {
 722                 /*
 723                  * We need to prepend the address family as
 724                  * a four byte field.  Cons up a dummy header
 725                  * to pacify bpf.  This is safe because bpf
 726                  * will only read from the mbuf (i.e., it won't
 727                  * try to free it or keep a pointer a to it).
 728                  */
 729                 struct mbuf m0;
 730                 u_int32_t af = AF_INET6;
 731
 732                 m0.m_next = m;
 733                 m0.m_len = 4;
 734                 m0.m_data = (char *)&af;
 735
 736 #ifdef HAVE_OLD_BPF
 737                 bpf_mtap(ifp, &m0);
 738 #else
 739                 bpf_mtap(ifp->if_bpf, &m0);
 740 #endif
 741         }
 742
 743         /*
 744          * Put the packet to the network layer input queue according to the
 745          * specified address family.
 746          * See net/if_gif.c for possible issues with packet processing
 747          * reorder due to extra queueing.
 748          */
 749         ifq = &ip6intrq;
 750         isr = NETISR_IPV6;
 751
 752         s = splimp();
 753         if (IF_QFULL(ifq)) {
 754                 IF_DROP(ifq);   /* update statistics */
 755                 m_freem(m);
 756                 splx(s);
 757                 return;
 758         }
 759         IF_ENQUEUE(ifq, m);
 760         schednetisr(isr);
 761         ifp->if_ipackets++;
 762         ifp->if_ibytes += m->m_pkthdr.len;
 763         splx(s);
 764
 765         return;
 766 }
 767
 768 /* ARGSUSED */
 769 static void
 770 stf_rtrequest(cmd, rt, sa)
 771         int cmd;
 772         struct rtentry *rt;
 773         struct sockaddr *sa;
 774 {
 775
 776         if (rt)
 777                 rt->rt_rmx.rmx_mtu = IPV6_MMTU;
 778 }
 779
 780 int
 781 stf_ioctl(ifp, cmd, data)
 782         struct ifnet *ifp;
 783         u_long cmd;
 784         void *data;
 785 {
 786         struct ifaddr *ifa;
 787         struct ifreq *ifr;
 788         struct sockaddr_in6 *sin6;
 789         int error;
 790
 791         error = 0;
 792         switch (cmd) {
 793         case SIOCSIFADDR:
 794                 ifa = (struct ifaddr *)data;
 795                 if (ifa == NULL || ifa->ifa_addr->sa_family != AF_INET6) {
 796                         error = EAFNOSUPPORT;
 797                         break;
 798                 }
 799                 sin6 = (struct sockaddr_in6 *)ifa->ifa_addr;
 800                 if (IN6_IS_ADDR_6TO4(&sin6->sin6_addr)) {
 801                         ifa->ifa_rtrequest = stf_rtrequest;
 802                         ifp->if_flags |= IFF_UP;
 803                 } else
 804                         error = EINVAL;
 805                 break;
 806
 807         case SIOCADDMULTI:
 808         case SIOCDELMULTI:
 809                 ifr = (struct ifreq *)data;
 810                 if (ifr && ifr->ifr_addr.sa_family == AF_INET6)
 811                         ;
 812                 else
 813                         error = EAFNOSUPPORT;
 814                 break;
 815
 816         default:
 817                 error = EINVAL;
 818                 break;
 819         }
 820
 821         return error;
 822 }