linux/net/ipv6/sit.c
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   1/*
   2 *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3 *      Linux INET6 implementation
   4 *
   5 *      Authors:
   6 *      Pedro Roque             <roque@di.fc.ul.pt>
   7 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   8 *
   9 *      This program is free software; you can redistribute it and/or
  10 *      modify it under the terms of the GNU General Public License
  11 *      as published by the Free Software Foundation; either version
  12 *      2 of the License, or (at your option) any later version.
  13 *
  14 *      Changes:
  15 * Roger Venning <r.venning@telstra.com>:       6to4 support
  16 * Nate Thompson <nate@thebog.net>:             6to4 support
  17 * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  18 */
  19
  20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22#include <linux/module.h>
  23#include <linux/capability.h>
  24#include <linux/errno.h>
  25#include <linux/types.h>
  26#include <linux/socket.h>
  27#include <linux/sockios.h>
  28#include <linux/net.h>
  29#include <linux/in6.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_arp.h>
  32#include <linux/icmp.h>
  33#include <linux/slab.h>
  34#include <asm/uaccess.h>
  35#include <linux/init.h>
  36#include <linux/netfilter_ipv4.h>
  37#include <linux/if_ether.h>
  38
  39#include <net/sock.h>
  40#include <net/snmp.h>
  41
  42#include <net/ipv6.h>
  43#include <net/protocol.h>
  44#include <net/transp_v6.h>
  45#include <net/ip6_fib.h>
  46#include <net/ip6_route.h>
  47#include <net/ndisc.h>
  48#include <net/addrconf.h>
  49#include <net/ip.h>
  50#include <net/udp.h>
  51#include <net/icmp.h>
  52#include <net/ip_tunnels.h>
  53#include <net/inet_ecn.h>
  54#include <net/xfrm.h>
  55#include <net/dsfield.h>
  56#include <net/net_namespace.h>
  57#include <net/netns/generic.h>
  58
  59/*
  60   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  61
  62   For comments look at net/ipv4/ip_gre.c --ANK
  63 */
  64
  65#define HASH_SIZE  16
  66#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  67
  68static bool log_ecn_error = true;
  69module_param(log_ecn_error, bool, 0644);
  70MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  71
  72static int ipip6_tunnel_init(struct net_device *dev);
  73static void ipip6_tunnel_setup(struct net_device *dev);
  74static void ipip6_dev_free(struct net_device *dev);
  75static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  76                      __be32 *v4dst);
  77static struct rtnl_link_ops sit_link_ops __read_mostly;
  78
  79static int sit_net_id __read_mostly;
  80struct sit_net {
  81        struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  82        struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  83        struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  84        struct ip_tunnel __rcu *tunnels_wc[1];
  85        struct ip_tunnel __rcu **tunnels[4];
  86
  87        struct net_device *fb_tunnel_dev;
  88};
  89
  90/*
  91 * Must be invoked with rcu_read_lock
  92 */
  93static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  94                struct net_device *dev, __be32 remote, __be32 local)
  95{
  96        unsigned int h0 = HASH(remote);
  97        unsigned int h1 = HASH(local);
  98        struct ip_tunnel *t;
  99        struct sit_net *sitn = net_generic(net, sit_net_id);
 100
 101        for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 102                if (local == t->parms.iph.saddr &&
 103                    remote == t->parms.iph.daddr &&
 104                    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 105                    (t->dev->flags & IFF_UP))
 106                        return t;
 107        }
 108        for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 109                if (remote == t->parms.iph.daddr &&
 110                    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 111                    (t->dev->flags & IFF_UP))
 112                        return t;
 113        }
 114        for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 115                if (local == t->parms.iph.saddr &&
 116                    (!dev || !t->parms.link || dev->ifindex == t->parms.link) &&
 117                    (t->dev->flags & IFF_UP))
 118                        return t;
 119        }
 120        t = rcu_dereference(sitn->tunnels_wc[0]);
 121        if (t && (t->dev->flags & IFF_UP))
 122                return t;
 123        return NULL;
 124}
 125
 126static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 127                struct ip_tunnel_parm *parms)
 128{
 129        __be32 remote = parms->iph.daddr;
 130        __be32 local = parms->iph.saddr;
 131        unsigned int h = 0;
 132        int prio = 0;
 133
 134        if (remote) {
 135                prio |= 2;
 136                h ^= HASH(remote);
 137        }
 138        if (local) {
 139                prio |= 1;
 140                h ^= HASH(local);
 141        }
 142        return &sitn->tunnels[prio][h];
 143}
 144
 145static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 146                struct ip_tunnel *t)
 147{
 148        return __ipip6_bucket(sitn, &t->parms);
 149}
 150
 151static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 152{
 153        struct ip_tunnel __rcu **tp;
 154        struct ip_tunnel *iter;
 155
 156        for (tp = ipip6_bucket(sitn, t);
 157             (iter = rtnl_dereference(*tp)) != NULL;
 158             tp = &iter->next) {
 159                if (t == iter) {
 160                        rcu_assign_pointer(*tp, t->next);
 161                        break;
 162                }
 163        }
 164}
 165
 166static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 167{
 168        struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 169
 170        rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 171        rcu_assign_pointer(*tp, t);
 172}
 173
 174static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 175{
 176#ifdef CONFIG_IPV6_SIT_6RD
 177        struct ip_tunnel *t = netdev_priv(dev);
 178
 179        if (t->dev == sitn->fb_tunnel_dev) {
 180                ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 181                t->ip6rd.relay_prefix = 0;
 182                t->ip6rd.prefixlen = 16;
 183                t->ip6rd.relay_prefixlen = 0;
 184        } else {
 185                struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 186                memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 187        }
 188#endif
 189}
 190
 191static int ipip6_tunnel_create(struct net_device *dev)
 192{
 193        struct ip_tunnel *t = netdev_priv(dev);
 194        struct net *net = dev_net(dev);
 195        struct sit_net *sitn = net_generic(net, sit_net_id);
 196        int err;
 197
 198        memcpy(dev->dev_addr, &t->parms.iph.saddr, 4);
 199        memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
 200
 201        if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 202                dev->priv_flags |= IFF_ISATAP;
 203
 204        dev->rtnl_link_ops = &sit_link_ops;
 205
 206        err = register_netdevice(dev);
 207        if (err < 0)
 208                goto out;
 209
 210        ipip6_tunnel_clone_6rd(dev, sitn);
 211
 212        dev_hold(dev);
 213
 214        ipip6_tunnel_link(sitn, t);
 215        return 0;
 216
 217out:
 218        return err;
 219}
 220
 221static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 222                struct ip_tunnel_parm *parms, int create)
 223{
 224        __be32 remote = parms->iph.daddr;
 225        __be32 local = parms->iph.saddr;
 226        struct ip_tunnel *t, *nt;
 227        struct ip_tunnel __rcu **tp;
 228        struct net_device *dev;
 229        char name[IFNAMSIZ];
 230        struct sit_net *sitn = net_generic(net, sit_net_id);
 231
 232        for (tp = __ipip6_bucket(sitn, parms);
 233            (t = rtnl_dereference(*tp)) != NULL;
 234             tp = &t->next) {
 235                if (local == t->parms.iph.saddr &&
 236                    remote == t->parms.iph.daddr &&
 237                    parms->link == t->parms.link) {
 238                        if (create)
 239                                return NULL;
 240                        else
 241                                return t;
 242                }
 243        }
 244        if (!create)
 245                goto failed;
 246
 247        if (parms->name[0])
 248                strlcpy(name, parms->name, IFNAMSIZ);
 249        else
 250                strcpy(name, "sit%d");
 251
 252        dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
 253                           ipip6_tunnel_setup);
 254        if (!dev)
 255                return NULL;
 256
 257        dev_net_set(dev, net);
 258
 259        nt = netdev_priv(dev);
 260
 261        nt->parms = *parms;
 262        if (ipip6_tunnel_create(dev) < 0)
 263                goto failed_free;
 264
 265        return nt;
 266
 267failed_free:
 268        ipip6_dev_free(dev);
 269failed:
 270        return NULL;
 271}
 272
 273#define for_each_prl_rcu(start)                 \
 274        for (prl = rcu_dereference(start);      \
 275             prl;                               \
 276             prl = rcu_dereference(prl->next))
 277
 278static struct ip_tunnel_prl_entry *
 279__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 280{
 281        struct ip_tunnel_prl_entry *prl;
 282
 283        for_each_prl_rcu(t->prl)
 284                if (prl->addr == addr)
 285                        break;
 286        return prl;
 287
 288}
 289
 290static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 291                                struct ip_tunnel_prl __user *a)
 292{
 293        struct ip_tunnel_prl kprl, *kp;
 294        struct ip_tunnel_prl_entry *prl;
 295        unsigned int cmax, c = 0, ca, len;
 296        int ret = 0;
 297
 298        if (copy_from_user(&kprl, a, sizeof(kprl)))
 299                return -EFAULT;
 300        cmax = kprl.datalen / sizeof(kprl);
 301        if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 302                cmax = 1;
 303
 304        /* For simple GET or for root users,
 305         * we try harder to allocate.
 306         */
 307        kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 308                kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 309                NULL;
 310
 311        rcu_read_lock();
 312
 313        ca = t->prl_count < cmax ? t->prl_count : cmax;
 314
 315        if (!kp) {
 316                /* We don't try hard to allocate much memory for
 317                 * non-root users.
 318                 * For root users, retry allocating enough memory for
 319                 * the answer.
 320                 */
 321                kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 322                if (!kp) {
 323                        ret = -ENOMEM;
 324                        goto out;
 325                }
 326        }
 327
 328        c = 0;
 329        for_each_prl_rcu(t->prl) {
 330                if (c >= cmax)
 331                        break;
 332                if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 333                        continue;
 334                kp[c].addr = prl->addr;
 335                kp[c].flags = prl->flags;
 336                c++;
 337                if (kprl.addr != htonl(INADDR_ANY))
 338                        break;
 339        }
 340out:
 341        rcu_read_unlock();
 342
 343        len = sizeof(*kp) * c;
 344        ret = 0;
 345        if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 346                ret = -EFAULT;
 347
 348        kfree(kp);
 349
 350        return ret;
 351}
 352
 353static int
 354ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 355{
 356        struct ip_tunnel_prl_entry *p;
 357        int err = 0;
 358
 359        if (a->addr == htonl(INADDR_ANY))
 360                return -EINVAL;
 361
 362        ASSERT_RTNL();
 363
 364        for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 365                if (p->addr == a->addr) {
 366                        if (chg) {
 367                                p->flags = a->flags;
 368                                goto out;
 369                        }
 370                        err = -EEXIST;
 371                        goto out;
 372                }
 373        }
 374
 375        if (chg) {
 376                err = -ENXIO;
 377                goto out;
 378        }
 379
 380        p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 381        if (!p) {
 382                err = -ENOBUFS;
 383                goto out;
 384        }
 385
 386        p->next = t->prl;
 387        p->addr = a->addr;
 388        p->flags = a->flags;
 389        t->prl_count++;
 390        rcu_assign_pointer(t->prl, p);
 391out:
 392        return err;
 393}
 394
 395static void prl_list_destroy_rcu(struct rcu_head *head)
 396{
 397        struct ip_tunnel_prl_entry *p, *n;
 398
 399        p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 400        do {
 401                n = rcu_dereference_protected(p->next, 1);
 402                kfree(p);
 403                p = n;
 404        } while (p);
 405}
 406
 407static int
 408ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 409{
 410        struct ip_tunnel_prl_entry *x;
 411        struct ip_tunnel_prl_entry __rcu **p;
 412        int err = 0;
 413
 414        ASSERT_RTNL();
 415
 416        if (a && a->addr != htonl(INADDR_ANY)) {
 417                for (p = &t->prl;
 418                     (x = rtnl_dereference(*p)) != NULL;
 419                     p = &x->next) {
 420                        if (x->addr == a->addr) {
 421                                *p = x->next;
 422                                kfree_rcu(x, rcu_head);
 423                                t->prl_count--;
 424                                goto out;
 425                        }
 426                }
 427                err = -ENXIO;
 428        } else {
 429                x = rtnl_dereference(t->prl);
 430                if (x) {
 431                        t->prl_count = 0;
 432                        call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 433                        t->prl = NULL;
 434                }
 435        }
 436out:
 437        return err;
 438}
 439
 440static int
 441isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 442{
 443        struct ip_tunnel_prl_entry *p;
 444        int ok = 1;
 445
 446        rcu_read_lock();
 447        p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 448        if (p) {
 449                if (p->flags & PRL_DEFAULT)
 450                        skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 451                else
 452                        skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 453        } else {
 454                const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 455
 456                if (ipv6_addr_is_isatap(addr6) &&
 457                    (addr6->s6_addr32[3] == iph->saddr) &&
 458                    ipv6_chk_prefix(addr6, t->dev))
 459                        skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 460                else
 461                        ok = 0;
 462        }
 463        rcu_read_unlock();
 464        return ok;
 465}
 466
 467static void ipip6_tunnel_uninit(struct net_device *dev)
 468{
 469        struct ip_tunnel *tunnel = netdev_priv(dev);
 470        struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 471
 472        if (dev == sitn->fb_tunnel_dev) {
 473                RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 474        } else {
 475                ipip6_tunnel_unlink(sitn, tunnel);
 476                ipip6_tunnel_del_prl(tunnel, NULL);
 477        }
 478        dst_cache_reset(&tunnel->dst_cache);
 479        dev_put(dev);
 480}
 481
 482/* Generate icmpv6 with type/code ICMPV6_DEST_UNREACH/ICMPV6_ADDR_UNREACH
 483 * if sufficient data bytes are available
 484 */
 485static int ipip6_err_gen_icmpv6_unreach(struct sk_buff *skb)
 486{
 487        int ihl = ((const struct iphdr *)skb->data)->ihl*4;
 488        struct rt6_info *rt;
 489        struct sk_buff *skb2;
 490
 491        if (!pskb_may_pull(skb, ihl + sizeof(struct ipv6hdr) + 8))
 492                return 1;
 493
 494        skb2 = skb_clone(skb, GFP_ATOMIC);
 495
 496        if (!skb2)
 497                return 1;
 498
 499        skb_dst_drop(skb2);
 500        skb_pull(skb2, ihl);
 501        skb_reset_network_header(skb2);
 502
 503        rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr, NULL, 0, 0);
 504
 505        if (rt && rt->dst.dev)
 506                skb2->dev = rt->dst.dev;
 507
 508        icmpv6_send(skb2, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0);
 509
 510        if (rt)
 511                ip6_rt_put(rt);
 512
 513        kfree_skb(skb2);
 514
 515        return 0;
 516}
 517
 518static int ipip6_err(struct sk_buff *skb, u32 info)
 519{
 520        const struct iphdr *iph = (const struct iphdr *)skb->data;
 521        const int type = icmp_hdr(skb)->type;
 522        const int code = icmp_hdr(skb)->code;
 523        struct ip_tunnel *t;
 524        int err;
 525
 526        switch (type) {
 527        default:
 528        case ICMP_PARAMETERPROB:
 529                return 0;
 530
 531        case ICMP_DEST_UNREACH:
 532                switch (code) {
 533                case ICMP_SR_FAILED:
 534                        /* Impossible event. */
 535                        return 0;
 536                default:
 537                        /* All others are translated to HOST_UNREACH.
 538                           rfc2003 contains "deep thoughts" about NET_UNREACH,
 539                           I believe they are just ether pollution. --ANK
 540                         */
 541                        break;
 542                }
 543                break;
 544        case ICMP_TIME_EXCEEDED:
 545                if (code != ICMP_EXC_TTL)
 546                        return 0;
 547                break;
 548        case ICMP_REDIRECT:
 549                break;
 550        }
 551
 552        err = -ENOENT;
 553
 554        t = ipip6_tunnel_lookup(dev_net(skb->dev),
 555                                skb->dev,
 556                                iph->daddr,
 557                                iph->saddr);
 558        if (!t)
 559                goto out;
 560
 561        if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 562                ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 563                                 t->parms.link, 0, IPPROTO_IPV6, 0);
 564                err = 0;
 565                goto out;
 566        }
 567        if (type == ICMP_REDIRECT) {
 568                ipv4_redirect(skb, dev_net(skb->dev), t->parms.link, 0,
 569                              IPPROTO_IPV6, 0);
 570                err = 0;
 571                goto out;
 572        }
 573
 574        if (t->parms.iph.daddr == 0)
 575                goto out;
 576
 577        err = 0;
 578        if (!ipip6_err_gen_icmpv6_unreach(skb))
 579                goto out;
 580
 581        if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 582                goto out;
 583
 584        if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 585                t->err_count++;
 586        else
 587                t->err_count = 1;
 588        t->err_time = jiffies;
 589out:
 590        return err;
 591}
 592
 593static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 594                                  const struct in6_addr *v6addr)
 595{
 596        __be32 v4embed = 0;
 597        if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 598                return true;
 599        return false;
 600}
 601
 602/* Checks if an address matches an address on the tunnel interface.
 603 * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
 604 * Long story:
 605 * This function is called after we considered the packet as spoofed
 606 * in is_spoofed_6rd.
 607 * We may have a router that is doing NAT for proto 41 packets
 608 * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
 609 * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
 610 * function will return true, dropping the packet.
 611 * But, we can still check if is spoofed against the IP
 612 * addresses associated with the interface.
 613 */
 614static bool only_dnatted(const struct ip_tunnel *tunnel,
 615        const struct in6_addr *v6dst)
 616{
 617        int prefix_len;
 618
 619#ifdef CONFIG_IPV6_SIT_6RD
 620        prefix_len = tunnel->ip6rd.prefixlen + 32
 621                - tunnel->ip6rd.relay_prefixlen;
 622#else
 623        prefix_len = 48;
 624#endif
 625        return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
 626}
 627
 628/* Returns true if a packet is spoofed */
 629static bool packet_is_spoofed(struct sk_buff *skb,
 630                              const struct iphdr *iph,
 631                              struct ip_tunnel *tunnel)
 632{
 633        const struct ipv6hdr *ipv6h;
 634
 635        if (tunnel->dev->priv_flags & IFF_ISATAP) {
 636                if (!isatap_chksrc(skb, iph, tunnel))
 637                        return true;
 638
 639                return false;
 640        }
 641
 642        if (tunnel->dev->flags & IFF_POINTOPOINT)
 643                return false;
 644
 645        ipv6h = ipv6_hdr(skb);
 646
 647        if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
 648                net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 649                                     &iph->saddr, &ipv6h->saddr,
 650                                     &iph->daddr, &ipv6h->daddr);
 651                return true;
 652        }
 653
 654        if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
 655                return false;
 656
 657        if (only_dnatted(tunnel, &ipv6h->daddr))
 658                return false;
 659
 660        net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
 661                             &iph->saddr, &ipv6h->saddr,
 662                             &iph->daddr, &ipv6h->daddr);
 663        return true;
 664}
 665
 666static int ipip6_rcv(struct sk_buff *skb)
 667{
 668        const struct iphdr *iph = ip_hdr(skb);
 669        struct ip_tunnel *tunnel;
 670        int err;
 671
 672        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 673                                     iph->saddr, iph->daddr);
 674        if (tunnel) {
 675                struct pcpu_sw_netstats *tstats;
 676
 677                if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 678                    tunnel->parms.iph.protocol != 0)
 679                        goto out;
 680
 681                skb->mac_header = skb->network_header;
 682                skb_reset_network_header(skb);
 683                IPCB(skb)->flags = 0;
 684                skb->dev = tunnel->dev;
 685
 686                if (packet_is_spoofed(skb, iph, tunnel)) {
 687                        tunnel->dev->stats.rx_errors++;
 688                        goto out;
 689                }
 690
 691                if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
 692                    !net_eq(tunnel->net, dev_net(tunnel->dev))))
 693                        goto out;
 694
 695                err = IP_ECN_decapsulate(iph, skb);
 696                if (unlikely(err)) {
 697                        if (log_ecn_error)
 698                                net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 699                                                     &iph->saddr, iph->tos);
 700                        if (err > 1) {
 701                                ++tunnel->dev->stats.rx_frame_errors;
 702                                ++tunnel->dev->stats.rx_errors;
 703                                goto out;
 704                        }
 705                }
 706
 707                tstats = this_cpu_ptr(tunnel->dev->tstats);
 708                u64_stats_update_begin(&tstats->syncp);
 709                tstats->rx_packets++;
 710                tstats->rx_bytes += skb->len;
 711                u64_stats_update_end(&tstats->syncp);
 712
 713                netif_rx(skb);
 714
 715                return 0;
 716        }
 717
 718        /* no tunnel matched,  let upstream know, ipsec may handle it */
 719        return 1;
 720out:
 721        kfree_skb(skb);
 722        return 0;
 723}
 724
 725static const struct tnl_ptk_info tpi = {
 726        /* no tunnel info required for ipip. */
 727        .proto = htons(ETH_P_IP),
 728};
 729
 730static int ipip_rcv(struct sk_buff *skb)
 731{
 732        const struct iphdr *iph;
 733        struct ip_tunnel *tunnel;
 734
 735        iph = ip_hdr(skb);
 736        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 737                                     iph->saddr, iph->daddr);
 738        if (tunnel) {
 739                if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 740                    tunnel->parms.iph.protocol != 0)
 741                        goto drop;
 742
 743                if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 744                        goto drop;
 745                if (iptunnel_pull_header(skb, 0, tpi.proto, false))
 746                        goto drop;
 747                return ip_tunnel_rcv(tunnel, skb, &tpi, NULL, log_ecn_error);
 748        }
 749
 750        return 1;
 751
 752drop:
 753        kfree_skb(skb);
 754        return 0;
 755}
 756
 757/*
 758 * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 759 * stores the embedded IPv4 address in v4dst and returns true.
 760 */
 761static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 762                      __be32 *v4dst)
 763{
 764#ifdef CONFIG_IPV6_SIT_6RD
 765        if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 766                              tunnel->ip6rd.prefixlen)) {
 767                unsigned int pbw0, pbi0;
 768                int pbi1;
 769                u32 d;
 770
 771                pbw0 = tunnel->ip6rd.prefixlen >> 5;
 772                pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 773
 774                d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 775                    tunnel->ip6rd.relay_prefixlen;
 776
 777                pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 778                if (pbi1 > 0)
 779                        d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 780                             (32 - pbi1);
 781
 782                *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 783                return true;
 784        }
 785#else
 786        if (v6dst->s6_addr16[0] == htons(0x2002)) {
 787                /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 788                memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 789                return true;
 790        }
 791#endif
 792        return false;
 793}
 794
 795static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 796                             const struct in6_addr *v6dst)
 797{
 798        __be32 dst = 0;
 799        check_6rd(tunnel, v6dst, &dst);
 800        return dst;
 801}
 802
 803/*
 804 *      This function assumes it is being called from dev_queue_xmit()
 805 *      and that skb is filled properly by that function.
 806 */
 807
 808static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 809                                     struct net_device *dev)
 810{
 811        struct ip_tunnel *tunnel = netdev_priv(dev);
 812        const struct iphdr  *tiph = &tunnel->parms.iph;
 813        const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 814        u8     tos = tunnel->parms.iph.tos;
 815        __be16 df = tiph->frag_off;
 816        struct rtable *rt;              /* Route to the other host */
 817        struct net_device *tdev;        /* Device to other host */
 818        unsigned int max_headroom;      /* The extra header space needed */
 819        __be32 dst = tiph->daddr;
 820        struct flowi4 fl4;
 821        int    mtu;
 822        const struct in6_addr *addr6;
 823        int addr_type;
 824        u8 ttl;
 825        u8 protocol = IPPROTO_IPV6;
 826        int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 827
 828        if (skb->protocol != htons(ETH_P_IPV6))
 829                goto tx_error;
 830
 831        if (tos == 1)
 832                tos = ipv6_get_dsfield(iph6);
 833
 834        /* ISATAP (RFC4214) - must come before 6to4 */
 835        if (dev->priv_flags & IFF_ISATAP) {
 836                struct neighbour *neigh = NULL;
 837                bool do_tx_error = false;
 838
 839                if (skb_dst(skb))
 840                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 841
 842                if (!neigh) {
 843                        net_dbg_ratelimited("nexthop == NULL\n");
 844                        goto tx_error;
 845                }
 846
 847                addr6 = (const struct in6_addr *)&neigh->primary_key;
 848                addr_type = ipv6_addr_type(addr6);
 849
 850                if ((addr_type & IPV6_ADDR_UNICAST) &&
 851                     ipv6_addr_is_isatap(addr6))
 852                        dst = addr6->s6_addr32[3];
 853                else
 854                        do_tx_error = true;
 855
 856                neigh_release(neigh);
 857                if (do_tx_error)
 858                        goto tx_error;
 859        }
 860
 861        if (!dst)
 862                dst = try_6rd(tunnel, &iph6->daddr);
 863
 864        if (!dst) {
 865                struct neighbour *neigh = NULL;
 866                bool do_tx_error = false;
 867
 868                if (skb_dst(skb))
 869                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 870
 871                if (!neigh) {
 872                        net_dbg_ratelimited("nexthop == NULL\n");
 873                        goto tx_error;
 874                }
 875
 876                addr6 = (const struct in6_addr *)&neigh->primary_key;
 877                addr_type = ipv6_addr_type(addr6);
 878
 879                if (addr_type == IPV6_ADDR_ANY) {
 880                        addr6 = &ipv6_hdr(skb)->daddr;
 881                        addr_type = ipv6_addr_type(addr6);
 882                }
 883
 884                if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 885                        dst = addr6->s6_addr32[3];
 886                else
 887                        do_tx_error = true;
 888
 889                neigh_release(neigh);
 890                if (do_tx_error)
 891                        goto tx_error;
 892        }
 893
 894        rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 895                                   dst, tiph->saddr,
 896                                   0, 0,
 897                                   IPPROTO_IPV6, RT_TOS(tos),
 898                                   tunnel->parms.link);
 899        if (IS_ERR(rt)) {
 900                dev->stats.tx_carrier_errors++;
 901                goto tx_error_icmp;
 902        }
 903        if (rt->rt_type != RTN_UNICAST) {
 904                ip_rt_put(rt);
 905                dev->stats.tx_carrier_errors++;
 906                goto tx_error_icmp;
 907        }
 908        tdev = rt->dst.dev;
 909
 910        if (tdev == dev) {
 911                ip_rt_put(rt);
 912                dev->stats.collisions++;
 913                goto tx_error;
 914        }
 915
 916        skb = iptunnel_handle_offloads(skb, SKB_GSO_SIT);
 917        if (IS_ERR(skb)) {
 918                ip_rt_put(rt);
 919                goto out;
 920        }
 921
 922        if (df) {
 923                mtu = dst_mtu(&rt->dst) - t_hlen;
 924
 925                if (mtu < 68) {
 926                        dev->stats.collisions++;
 927                        ip_rt_put(rt);
 928                        goto tx_error;
 929                }
 930
 931                if (mtu < IPV6_MIN_MTU) {
 932                        mtu = IPV6_MIN_MTU;
 933                        df = 0;
 934                }
 935
 936                if (tunnel->parms.iph.daddr && skb_dst(skb))
 937                        skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 938
 939                if (skb->len > mtu && !skb_is_gso(skb)) {
 940                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 941                        ip_rt_put(rt);
 942                        goto tx_error;
 943                }
 944        }
 945
 946        if (tunnel->err_count > 0) {
 947                if (time_before(jiffies,
 948                                tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 949                        tunnel->err_count--;
 950                        dst_link_failure(skb);
 951                } else
 952                        tunnel->err_count = 0;
 953        }
 954
 955        /*
 956         * Okay, now see if we can stuff it in the buffer as-is.
 957         */
 958        max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
 959
 960        if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 961            (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 962                struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 963                if (!new_skb) {
 964                        ip_rt_put(rt);
 965                        dev->stats.tx_dropped++;
 966                        kfree_skb(skb);
 967                        return NETDEV_TX_OK;
 968                }
 969                if (skb->sk)
 970                        skb_set_owner_w(new_skb, skb->sk);
 971                dev_kfree_skb(skb);
 972                skb = new_skb;
 973                iph6 = ipv6_hdr(skb);
 974        }
 975        ttl = tiph->ttl;
 976        if (ttl == 0)
 977                ttl = iph6->hop_limit;
 978        tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 979
 980        if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0) {
 981                ip_rt_put(rt);
 982                goto tx_error;
 983        }
 984
 985        skb_set_inner_ipproto(skb, IPPROTO_IPV6);
 986
 987        iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
 988                      df, !net_eq(tunnel->net, dev_net(dev)));
 989        return NETDEV_TX_OK;
 990
 991tx_error_icmp:
 992        dst_link_failure(skb);
 993tx_error:
 994        kfree_skb(skb);
 995out:
 996        dev->stats.tx_errors++;
 997        return NETDEV_TX_OK;
 998}
 999
1000static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
1001{
1002        struct ip_tunnel *tunnel = netdev_priv(dev);
1003        const struct iphdr  *tiph = &tunnel->parms.iph;
1004
1005        skb = iptunnel_handle_offloads(skb, SKB_GSO_IPIP);
1006        if (IS_ERR(skb))
1007                goto out;
1008
1009        skb_set_inner_ipproto(skb, IPPROTO_IPIP);
1010
1011        ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
1012        return NETDEV_TX_OK;
1013out:
1014        dev->stats.tx_errors++;
1015        return NETDEV_TX_OK;
1016}
1017
1018static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1019                                   struct net_device *dev)
1020{
1021        switch (skb->protocol) {
1022        case htons(ETH_P_IP):
1023                ipip_tunnel_xmit(skb, dev);
1024                break;
1025        case htons(ETH_P_IPV6):
1026                ipip6_tunnel_xmit(skb, dev);
1027                break;
1028        default:
1029                goto tx_err;
1030        }
1031
1032        return NETDEV_TX_OK;
1033
1034tx_err:
1035        dev->stats.tx_errors++;
1036        kfree_skb(skb);
1037        return NETDEV_TX_OK;
1038
1039}
1040
1041static void ipip6_tunnel_bind_dev(struct net_device *dev)
1042{
1043        struct net_device *tdev = NULL;
1044        struct ip_tunnel *tunnel;
1045        const struct iphdr *iph;
1046        struct flowi4 fl4;
1047
1048        tunnel = netdev_priv(dev);
1049        iph = &tunnel->parms.iph;
1050
1051        if (iph->daddr) {
1052                struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1053                                                          NULL,
1054                                                          iph->daddr, iph->saddr,
1055                                                          0, 0,
1056                                                          IPPROTO_IPV6,
1057                                                          RT_TOS(iph->tos),
1058                                                          tunnel->parms.link);
1059
1060                if (!IS_ERR(rt)) {
1061                        tdev = rt->dst.dev;
1062                        ip_rt_put(rt);
1063                }
1064                dev->flags |= IFF_POINTOPOINT;
1065        }
1066
1067        if (!tdev && tunnel->parms.link)
1068                tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1069
1070        if (tdev) {
1071                int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1072
1073                dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
1074                dev->mtu = tdev->mtu - t_hlen;
1075                if (dev->mtu < IPV6_MIN_MTU)
1076                        dev->mtu = IPV6_MIN_MTU;
1077        }
1078}
1079
1080static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
1081{
1082        struct net *net = t->net;
1083        struct sit_net *sitn = net_generic(net, sit_net_id);
1084
1085        ipip6_tunnel_unlink(sitn, t);
1086        synchronize_net();
1087        t->parms.iph.saddr = p->iph.saddr;
1088        t->parms.iph.daddr = p->iph.daddr;
1089        memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
1090        memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1091        ipip6_tunnel_link(sitn, t);
1092        t->parms.iph.ttl = p->iph.ttl;
1093        t->parms.iph.tos = p->iph.tos;
1094        if (t->parms.link != p->link) {
1095                t->parms.link = p->link;
1096                ipip6_tunnel_bind_dev(t->dev);
1097        }
1098        dst_cache_reset(&t->dst_cache);
1099        netdev_state_change(t->dev);
1100}
1101
1102#ifdef CONFIG_IPV6_SIT_6RD
1103static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1104                                   struct ip_tunnel_6rd *ip6rd)
1105{
1106        struct in6_addr prefix;
1107        __be32 relay_prefix;
1108
1109        if (ip6rd->relay_prefixlen > 32 ||
1110            ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1111                return -EINVAL;
1112
1113        ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1114        if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1115                return -EINVAL;
1116        if (ip6rd->relay_prefixlen)
1117                relay_prefix = ip6rd->relay_prefix &
1118                               htonl(0xffffffffUL <<
1119                                     (32 - ip6rd->relay_prefixlen));
1120        else
1121                relay_prefix = 0;
1122        if (relay_prefix != ip6rd->relay_prefix)
1123                return -EINVAL;
1124
1125        t->ip6rd.prefix = prefix;
1126        t->ip6rd.relay_prefix = relay_prefix;
1127        t->ip6rd.prefixlen = ip6rd->prefixlen;
1128        t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1129        dst_cache_reset(&t->dst_cache);
1130        netdev_state_change(t->dev);
1131        return 0;
1132}
1133#endif
1134
1135static int
1136ipip6_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1137{
1138        int err = 0;
1139        struct ip_tunnel_parm p;
1140        struct ip_tunnel_prl prl;
1141        struct ip_tunnel *t = netdev_priv(dev);
1142        struct net *net = t->net;
1143        struct sit_net *sitn = net_generic(net, sit_net_id);
1144#ifdef CONFIG_IPV6_SIT_6RD
1145        struct ip_tunnel_6rd ip6rd;
1146#endif
1147
1148        switch (cmd) {
1149        case SIOCGETTUNNEL:
1150#ifdef CONFIG_IPV6_SIT_6RD
1151        case SIOCGET6RD:
1152#endif
1153                if (dev == sitn->fb_tunnel_dev) {
1154                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1155                                err = -EFAULT;
1156                                break;
1157                        }
1158                        t = ipip6_tunnel_locate(net, &p, 0);
1159                        if (!t)
1160                                t = netdev_priv(dev);
1161                }
1162
1163                err = -EFAULT;
1164                if (cmd == SIOCGETTUNNEL) {
1165                        memcpy(&p, &t->parms, sizeof(p));
1166                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1167                                         sizeof(p)))
1168                                goto done;
1169#ifdef CONFIG_IPV6_SIT_6RD
1170                } else {
1171                        ip6rd.prefix = t->ip6rd.prefix;
1172                        ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1173                        ip6rd.prefixlen = t->ip6rd.prefixlen;
1174                        ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1175                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1176                                         sizeof(ip6rd)))
1177                                goto done;
1178#endif
1179                }
1180                err = 0;
1181                break;
1182
1183        case SIOCADDTUNNEL:
1184        case SIOCCHGTUNNEL:
1185                err = -EPERM;
1186                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1187                        goto done;
1188
1189                err = -EFAULT;
1190                if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1191                        goto done;
1192
1193                err = -EINVAL;
1194                if (p.iph.protocol != IPPROTO_IPV6 &&
1195                    p.iph.protocol != IPPROTO_IPIP &&
1196                    p.iph.protocol != 0)
1197                        goto done;
1198                if (p.iph.version != 4 ||
1199                    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1200                        goto done;
1201                if (p.iph.ttl)
1202                        p.iph.frag_off |= htons(IP_DF);
1203
1204                t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1205
1206                if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1207                        if (t) {
1208                                if (t->dev != dev) {
1209                                        err = -EEXIST;
1210                                        break;
1211                                }
1212                        } else {
1213                                if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1214                                    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1215                                        err = -EINVAL;
1216                                        break;
1217                                }
1218                                t = netdev_priv(dev);
1219                        }
1220
1221                        ipip6_tunnel_update(t, &p);
1222                }
1223
1224                if (t) {
1225                        err = 0;
1226                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1227                                err = -EFAULT;
1228                } else
1229                        err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1230                break;
1231
1232        case SIOCDELTUNNEL:
1233                err = -EPERM;
1234                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1235                        goto done;
1236
1237                if (dev == sitn->fb_tunnel_dev) {
1238                        err = -EFAULT;
1239                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1240                                goto done;
1241                        err = -ENOENT;
1242                        t = ipip6_tunnel_locate(net, &p, 0);
1243                        if (!t)
1244                                goto done;
1245                        err = -EPERM;
1246                        if (t == netdev_priv(sitn->fb_tunnel_dev))
1247                                goto done;
1248                        dev = t->dev;
1249                }
1250                unregister_netdevice(dev);
1251                err = 0;
1252                break;
1253
1254        case SIOCGETPRL:
1255                err = -EINVAL;
1256                if (dev == sitn->fb_tunnel_dev)
1257                        goto done;
1258                err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1259                break;
1260
1261        case SIOCADDPRL:
1262        case SIOCDELPRL:
1263        case SIOCCHGPRL:
1264                err = -EPERM;
1265                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1266                        goto done;
1267                err = -EINVAL;
1268                if (dev == sitn->fb_tunnel_dev)
1269                        goto done;
1270                err = -EFAULT;
1271                if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1272                        goto done;
1273
1274                switch (cmd) {
1275                case SIOCDELPRL:
1276                        err = ipip6_tunnel_del_prl(t, &prl);
1277                        break;
1278                case SIOCADDPRL:
1279                case SIOCCHGPRL:
1280                        err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1281                        break;
1282                }
1283                dst_cache_reset(&t->dst_cache);
1284                netdev_state_change(dev);
1285                break;
1286
1287#ifdef CONFIG_IPV6_SIT_6RD
1288        case SIOCADD6RD:
1289        case SIOCCHG6RD:
1290        case SIOCDEL6RD:
1291                err = -EPERM;
1292                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1293                        goto done;
1294
1295                err = -EFAULT;
1296                if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1297                                   sizeof(ip6rd)))
1298                        goto done;
1299
1300                if (cmd != SIOCDEL6RD) {
1301                        err = ipip6_tunnel_update_6rd(t, &ip6rd);
1302                        if (err < 0)
1303                                goto done;
1304                } else
1305                        ipip6_tunnel_clone_6rd(dev, sitn);
1306
1307                err = 0;
1308                break;
1309#endif
1310
1311        default:
1312                err = -EINVAL;
1313        }
1314
1315done:
1316        return err;
1317}
1318
1319static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1320{
1321        struct ip_tunnel *tunnel = netdev_priv(dev);
1322        int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1323
1324        if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - t_hlen)
1325                return -EINVAL;
1326        dev->mtu = new_mtu;
1327        return 0;
1328}
1329
1330static const struct net_device_ops ipip6_netdev_ops = {
1331        .ndo_init       = ipip6_tunnel_init,
1332        .ndo_uninit     = ipip6_tunnel_uninit,
1333        .ndo_start_xmit = sit_tunnel_xmit,
1334        .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1335        .ndo_change_mtu = ipip6_tunnel_change_mtu,
1336        .ndo_get_stats64 = ip_tunnel_get_stats64,
1337        .ndo_get_iflink = ip_tunnel_get_iflink,
1338};
1339
1340static void ipip6_dev_free(struct net_device *dev)
1341{
1342        struct ip_tunnel *tunnel = netdev_priv(dev);
1343
1344        dst_cache_destroy(&tunnel->dst_cache);
1345        free_percpu(dev->tstats);
1346        free_netdev(dev);
1347}
1348
1349#define SIT_FEATURES (NETIF_F_SG           | \
1350                      NETIF_F_FRAGLIST     | \
1351                      NETIF_F_HIGHDMA      | \
1352                      NETIF_F_GSO_SOFTWARE | \
1353                      NETIF_F_HW_CSUM)
1354
1355static void ipip6_tunnel_setup(struct net_device *dev)
1356{
1357        struct ip_tunnel *tunnel = netdev_priv(dev);
1358        int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1359
1360        dev->netdev_ops         = &ipip6_netdev_ops;
1361        dev->destructor         = ipip6_dev_free;
1362
1363        dev->type               = ARPHRD_SIT;
1364        dev->hard_header_len    = LL_MAX_HEADER + t_hlen;
1365        dev->mtu                = ETH_DATA_LEN - t_hlen;
1366        dev->flags              = IFF_NOARP;
1367        netif_keep_dst(dev);
1368        dev->addr_len           = 4;
1369        dev->features           |= NETIF_F_LLTX;
1370        dev->features           |= SIT_FEATURES;
1371        dev->hw_features        |= SIT_FEATURES;
1372}
1373
1374static int ipip6_tunnel_init(struct net_device *dev)
1375{
1376        struct ip_tunnel *tunnel = netdev_priv(dev);
1377        int err;
1378
1379        tunnel->dev = dev;
1380        tunnel->net = dev_net(dev);
1381        strcpy(tunnel->parms.name, dev->name);
1382
1383        ipip6_tunnel_bind_dev(dev);
1384        dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1385        if (!dev->tstats)
1386                return -ENOMEM;
1387
1388        err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1389        if (err) {
1390                free_percpu(dev->tstats);
1391                return err;
1392        }
1393
1394        return 0;
1395}
1396
1397static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1398{
1399        struct ip_tunnel *tunnel = netdev_priv(dev);
1400        struct iphdr *iph = &tunnel->parms.iph;
1401        struct net *net = dev_net(dev);
1402        struct sit_net *sitn = net_generic(net, sit_net_id);
1403
1404        iph->version            = 4;
1405        iph->protocol           = IPPROTO_IPV6;
1406        iph->ihl                = 5;
1407        iph->ttl                = 64;
1408
1409        dev_hold(dev);
1410        rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1411}
1412
1413static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1414{
1415        u8 proto;
1416
1417        if (!data || !data[IFLA_IPTUN_PROTO])
1418                return 0;
1419
1420        proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1421        if (proto != IPPROTO_IPV6 &&
1422            proto != IPPROTO_IPIP &&
1423            proto != 0)
1424                return -EINVAL;
1425
1426        return 0;
1427}
1428
1429static void ipip6_netlink_parms(struct nlattr *data[],
1430                                struct ip_tunnel_parm *parms)
1431{
1432        memset(parms, 0, sizeof(*parms));
1433
1434        parms->iph.version = 4;
1435        parms->iph.protocol = IPPROTO_IPV6;
1436        parms->iph.ihl = 5;
1437        parms->iph.ttl = 64;
1438
1439        if (!data)
1440                return;
1441
1442        if (data[IFLA_IPTUN_LINK])
1443                parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1444
1445        if (data[IFLA_IPTUN_LOCAL])
1446                parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1447
1448        if (data[IFLA_IPTUN_REMOTE])
1449                parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1450
1451        if (data[IFLA_IPTUN_TTL]) {
1452                parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1453                if (parms->iph.ttl)
1454                        parms->iph.frag_off = htons(IP_DF);
1455        }
1456
1457        if (data[IFLA_IPTUN_TOS])
1458                parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1459
1460        if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1461                parms->iph.frag_off = htons(IP_DF);
1462
1463        if (data[IFLA_IPTUN_FLAGS])
1464                parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1465
1466        if (data[IFLA_IPTUN_PROTO])
1467                parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1468
1469}
1470
1471/* This function returns true when ENCAP attributes are present in the nl msg */
1472static bool ipip6_netlink_encap_parms(struct nlattr *data[],
1473                                      struct ip_tunnel_encap *ipencap)
1474{
1475        bool ret = false;
1476
1477        memset(ipencap, 0, sizeof(*ipencap));
1478
1479        if (!data)
1480                return ret;
1481
1482        if (data[IFLA_IPTUN_ENCAP_TYPE]) {
1483                ret = true;
1484                ipencap->type = nla_get_u16(data[IFLA_IPTUN_ENCAP_TYPE]);
1485        }
1486
1487        if (data[IFLA_IPTUN_ENCAP_FLAGS]) {
1488                ret = true;
1489                ipencap->flags = nla_get_u16(data[IFLA_IPTUN_ENCAP_FLAGS]);
1490        }
1491
1492        if (data[IFLA_IPTUN_ENCAP_SPORT]) {
1493                ret = true;
1494                ipencap->sport = nla_get_be16(data[IFLA_IPTUN_ENCAP_SPORT]);
1495        }
1496
1497        if (data[IFLA_IPTUN_ENCAP_DPORT]) {
1498                ret = true;
1499                ipencap->dport = nla_get_be16(data[IFLA_IPTUN_ENCAP_DPORT]);
1500        }
1501
1502        return ret;
1503}
1504
1505#ifdef CONFIG_IPV6_SIT_6RD
1506/* This function returns true when 6RD attributes are present in the nl msg */
1507static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1508                                    struct ip_tunnel_6rd *ip6rd)
1509{
1510        bool ret = false;
1511        memset(ip6rd, 0, sizeof(*ip6rd));
1512
1513        if (!data)
1514                return ret;
1515
1516        if (data[IFLA_IPTUN_6RD_PREFIX]) {
1517                ret = true;
1518                ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1519        }
1520
1521        if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1522                ret = true;
1523                ip6rd->relay_prefix =
1524                        nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1525        }
1526
1527        if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1528                ret = true;
1529                ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1530        }
1531
1532        if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1533                ret = true;
1534                ip6rd->relay_prefixlen =
1535                        nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1536        }
1537
1538        return ret;
1539}
1540#endif
1541
1542static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1543                         struct nlattr *tb[], struct nlattr *data[])
1544{
1545        struct net *net = dev_net(dev);
1546        struct ip_tunnel *nt;
1547        struct ip_tunnel_encap ipencap;
1548#ifdef CONFIG_IPV6_SIT_6RD
1549        struct ip_tunnel_6rd ip6rd;
1550#endif
1551        int err;
1552
1553        nt = netdev_priv(dev);
1554
1555        if (ipip6_netlink_encap_parms(data, &ipencap)) {
1556                err = ip_tunnel_encap_setup(nt, &ipencap);
1557                if (err < 0)
1558                        return err;
1559        }
1560
1561        ipip6_netlink_parms(data, &nt->parms);
1562
1563        if (ipip6_tunnel_locate(net, &nt->parms, 0))
1564                return -EEXIST;
1565
1566        err = ipip6_tunnel_create(dev);
1567        if (err < 0)
1568                return err;
1569
1570#ifdef CONFIG_IPV6_SIT_6RD
1571        if (ipip6_netlink_6rd_parms(data, &ip6rd))
1572                err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1573#endif
1574
1575        return err;
1576}
1577
1578static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1579                          struct nlattr *data[])
1580{
1581        struct ip_tunnel *t = netdev_priv(dev);
1582        struct ip_tunnel_parm p;
1583        struct ip_tunnel_encap ipencap;
1584        struct net *net = t->net;
1585        struct sit_net *sitn = net_generic(net, sit_net_id);
1586#ifdef CONFIG_IPV6_SIT_6RD
1587        struct ip_tunnel_6rd ip6rd;
1588#endif
1589        int err;
1590
1591        if (dev == sitn->fb_tunnel_dev)
1592                return -EINVAL;
1593
1594        if (ipip6_netlink_encap_parms(data, &ipencap)) {
1595                err = ip_tunnel_encap_setup(t, &ipencap);
1596                if (err < 0)
1597                        return err;
1598        }
1599
1600        ipip6_netlink_parms(data, &p);
1601
1602        if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1603            (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1604                return -EINVAL;
1605
1606        t = ipip6_tunnel_locate(net, &p, 0);
1607
1608        if (t) {
1609                if (t->dev != dev)
1610                        return -EEXIST;
1611        } else
1612                t = netdev_priv(dev);
1613
1614        ipip6_tunnel_update(t, &p);
1615
1616#ifdef CONFIG_IPV6_SIT_6RD
1617        if (ipip6_netlink_6rd_parms(data, &ip6rd))
1618                return ipip6_tunnel_update_6rd(t, &ip6rd);
1619#endif
1620
1621        return 0;
1622}
1623
1624static size_t ipip6_get_size(const struct net_device *dev)
1625{
1626        return
1627                /* IFLA_IPTUN_LINK */
1628                nla_total_size(4) +
1629                /* IFLA_IPTUN_LOCAL */
1630                nla_total_size(4) +
1631                /* IFLA_IPTUN_REMOTE */
1632                nla_total_size(4) +
1633                /* IFLA_IPTUN_TTL */
1634                nla_total_size(1) +
1635                /* IFLA_IPTUN_TOS */
1636                nla_total_size(1) +
1637                /* IFLA_IPTUN_PMTUDISC */
1638                nla_total_size(1) +
1639                /* IFLA_IPTUN_FLAGS */
1640                nla_total_size(2) +
1641                /* IFLA_IPTUN_PROTO */
1642                nla_total_size(1) +
1643#ifdef CONFIG_IPV6_SIT_6RD
1644                /* IFLA_IPTUN_6RD_PREFIX */
1645                nla_total_size(sizeof(struct in6_addr)) +
1646                /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1647                nla_total_size(4) +
1648                /* IFLA_IPTUN_6RD_PREFIXLEN */
1649                nla_total_size(2) +
1650                /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1651                nla_total_size(2) +
1652#endif
1653                /* IFLA_IPTUN_ENCAP_TYPE */
1654                nla_total_size(2) +
1655                /* IFLA_IPTUN_ENCAP_FLAGS */
1656                nla_total_size(2) +
1657                /* IFLA_IPTUN_ENCAP_SPORT */
1658                nla_total_size(2) +
1659                /* IFLA_IPTUN_ENCAP_DPORT */
1660                nla_total_size(2) +
1661                0;
1662}
1663
1664static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1665{
1666        struct ip_tunnel *tunnel = netdev_priv(dev);
1667        struct ip_tunnel_parm *parm = &tunnel->parms;
1668
1669        if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1670            nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1671            nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1672            nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1673            nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1674            nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1675                       !!(parm->iph.frag_off & htons(IP_DF))) ||
1676            nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1677            nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1678                goto nla_put_failure;
1679
1680#ifdef CONFIG_IPV6_SIT_6RD
1681        if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1682                             &tunnel->ip6rd.prefix) ||
1683            nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1684                            tunnel->ip6rd.relay_prefix) ||
1685            nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1686                        tunnel->ip6rd.prefixlen) ||
1687            nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1688                        tunnel->ip6rd.relay_prefixlen))
1689                goto nla_put_failure;
1690#endif
1691
1692        if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1693                        tunnel->encap.type) ||
1694            nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1695                        tunnel->encap.sport) ||
1696            nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1697                        tunnel->encap.dport) ||
1698            nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1699                        tunnel->encap.flags))
1700                goto nla_put_failure;
1701
1702        return 0;
1703
1704nla_put_failure:
1705        return -EMSGSIZE;
1706}
1707
1708static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1709        [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1710        [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1711        [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1712        [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1713        [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1714        [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1715        [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1716        [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1717#ifdef CONFIG_IPV6_SIT_6RD
1718        [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1719        [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1720        [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1721        [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1722#endif
1723        [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1724        [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1725        [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1726        [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1727};
1728
1729static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1730{
1731        struct net *net = dev_net(dev);
1732        struct sit_net *sitn = net_generic(net, sit_net_id);
1733
1734        if (dev != sitn->fb_tunnel_dev)
1735                unregister_netdevice_queue(dev, head);
1736}
1737
1738static struct rtnl_link_ops sit_link_ops __read_mostly = {
1739        .kind           = "sit",
1740        .maxtype        = IFLA_IPTUN_MAX,
1741        .policy         = ipip6_policy,
1742        .priv_size      = sizeof(struct ip_tunnel),
1743        .setup          = ipip6_tunnel_setup,
1744        .validate       = ipip6_validate,
1745        .newlink        = ipip6_newlink,
1746        .changelink     = ipip6_changelink,
1747        .get_size       = ipip6_get_size,
1748        .fill_info      = ipip6_fill_info,
1749        .dellink        = ipip6_dellink,
1750        .get_link_net   = ip_tunnel_get_link_net,
1751};
1752
1753static struct xfrm_tunnel sit_handler __read_mostly = {
1754        .handler        =       ipip6_rcv,
1755        .err_handler    =       ipip6_err,
1756        .priority       =       1,
1757};
1758
1759static struct xfrm_tunnel ipip_handler __read_mostly = {
1760        .handler        =       ipip_rcv,
1761        .err_handler    =       ipip6_err,
1762        .priority       =       2,
1763};
1764
1765static void __net_exit sit_destroy_tunnels(struct net *net,
1766                                           struct list_head *head)
1767{
1768        struct sit_net *sitn = net_generic(net, sit_net_id);
1769        struct net_device *dev, *aux;
1770        int prio;
1771
1772        for_each_netdev_safe(net, dev, aux)
1773                if (dev->rtnl_link_ops == &sit_link_ops)
1774                        unregister_netdevice_queue(dev, head);
1775
1776        for (prio = 1; prio < 4; prio++) {
1777                int h;
1778                for (h = 0; h < HASH_SIZE; h++) {
1779                        struct ip_tunnel *t;
1780
1781                        t = rtnl_dereference(sitn->tunnels[prio][h]);
1782                        while (t) {
1783                                /* If dev is in the same netns, it has already
1784                                 * been added to the list by the previous loop.
1785                                 */
1786                                if (!net_eq(dev_net(t->dev), net))
1787                                        unregister_netdevice_queue(t->dev,
1788                                                                   head);
1789                                t = rtnl_dereference(t->next);
1790                        }
1791                }
1792        }
1793}
1794
1795static int __net_init sit_init_net(struct net *net)
1796{
1797        struct sit_net *sitn = net_generic(net, sit_net_id);
1798        struct ip_tunnel *t;
1799        int err;
1800
1801        sitn->tunnels[0] = sitn->tunnels_wc;
1802        sitn->tunnels[1] = sitn->tunnels_l;
1803        sitn->tunnels[2] = sitn->tunnels_r;
1804        sitn->tunnels[3] = sitn->tunnels_r_l;
1805
1806        sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1807                                           NET_NAME_UNKNOWN,
1808                                           ipip6_tunnel_setup);
1809        if (!sitn->fb_tunnel_dev) {
1810                err = -ENOMEM;
1811                goto err_alloc_dev;
1812        }
1813        dev_net_set(sitn->fb_tunnel_dev, net);
1814        sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1815        /* FB netdevice is special: we have one, and only one per netns.
1816         * Allowing to move it to another netns is clearly unsafe.
1817         */
1818        sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1819
1820        err = register_netdev(sitn->fb_tunnel_dev);
1821        if (err)
1822                goto err_reg_dev;
1823
1824        ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1825        ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1826
1827        t = netdev_priv(sitn->fb_tunnel_dev);
1828
1829        strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1830        return 0;
1831
1832err_reg_dev:
1833        ipip6_dev_free(sitn->fb_tunnel_dev);
1834err_alloc_dev:
1835        return err;
1836}
1837
1838static void __net_exit sit_exit_net(struct net *net)
1839{
1840        LIST_HEAD(list);
1841
1842        rtnl_lock();
1843        sit_destroy_tunnels(net, &list);
1844        unregister_netdevice_many(&list);
1845        rtnl_unlock();
1846}
1847
1848static struct pernet_operations sit_net_ops = {
1849        .init = sit_init_net,
1850        .exit = sit_exit_net,
1851        .id   = &sit_net_id,
1852        .size = sizeof(struct sit_net),
1853};
1854
1855static void __exit sit_cleanup(void)
1856{
1857        rtnl_link_unregister(&sit_link_ops);
1858        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1859        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1860
1861        unregister_pernet_device(&sit_net_ops);
1862        rcu_barrier(); /* Wait for completion of call_rcu()'s */
1863}
1864
1865static int __init sit_init(void)
1866{
1867        int err;
1868
1869        pr_info("IPv6 over IPv4 tunneling driver\n");
1870
1871        err = register_pernet_device(&sit_net_ops);
1872        if (err < 0)
1873                return err;
1874        err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1875        if (err < 0) {
1876                pr_info("%s: can't register ip6ip4\n", __func__);
1877                goto xfrm_tunnel_failed;
1878        }
1879        err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1880        if (err < 0) {
1881                pr_info("%s: can't register ip4ip4\n", __func__);
1882                goto xfrm_tunnel4_failed;
1883        }
1884        err = rtnl_link_register(&sit_link_ops);
1885        if (err < 0)
1886                goto rtnl_link_failed;
1887
1888out:
1889        return err;
1890
1891rtnl_link_failed:
1892        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1893xfrm_tunnel4_failed:
1894        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1895xfrm_tunnel_failed:
1896        unregister_pernet_device(&sit_net_ops);
1897        goto out;
1898}
1899
1900module_init(sit_init);
1901module_exit(sit_cleanup);
1902MODULE_LICENSE("GPL");
1903MODULE_ALIAS_RTNL_LINK("sit");
1904MODULE_ALIAS_NETDEV("sit0");
1905