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/ipip.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 int ipip6_tunnel_init(struct net_device *dev);
  69static void ipip6_tunnel_setup(struct net_device *dev);
  70static void ipip6_dev_free(struct net_device *dev);
  71
  72static int sit_net_id __read_mostly;
  73struct sit_net {
  74        struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  75        struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  76        struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  77        struct ip_tunnel __rcu *tunnels_wc[1];
  78        struct ip_tunnel __rcu **tunnels[4];
  79
  80        struct net_device *fb_tunnel_dev;
  81};
  82
  83/*
  84 * Locking : hash tables are protected by RCU and RTNL
  85 */
  86
  87#define for_each_ip_tunnel_rcu(start) \
  88        for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
  89
  90/* often modified stats are per cpu, other are shared (netdev->stats) */
  91struct pcpu_tstats {
  92        u64     rx_packets;
  93        u64     rx_bytes;
  94        u64     tx_packets;
  95        u64     tx_bytes;
  96        struct u64_stats_sync   syncp;
  97};
  98
  99static struct rtnl_link_stats64 *ipip6_get_stats64(struct net_device *dev,
 100                                                   struct rtnl_link_stats64 *tot)
 101{
 102        int i;
 103
 104        for_each_possible_cpu(i) {
 105                const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 106                u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 107                unsigned int start;
 108
 109                do {
 110                        start = u64_stats_fetch_begin_bh(&tstats->syncp);
 111                        rx_packets = tstats->rx_packets;
 112                        tx_packets = tstats->tx_packets;
 113                        rx_bytes = tstats->rx_bytes;
 114                        tx_bytes = tstats->tx_bytes;
 115                } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
 116
 117                tot->rx_packets += rx_packets;
 118                tot->tx_packets += tx_packets;
 119                tot->rx_bytes   += rx_bytes;
 120                tot->tx_bytes   += tx_bytes;
 121        }
 122
 123        tot->rx_errors = dev->stats.rx_errors;
 124        tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
 125        tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
 126        tot->tx_dropped = dev->stats.tx_dropped;
 127        tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
 128        tot->tx_errors = dev->stats.tx_errors;
 129
 130        return tot;
 131}
 132
 133/*
 134 * Must be invoked with rcu_read_lock
 135 */
 136static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
 137                struct net_device *dev, __be32 remote, __be32 local)
 138{
 139        unsigned int h0 = HASH(remote);
 140        unsigned int h1 = HASH(local);
 141        struct ip_tunnel *t;
 142        struct sit_net *sitn = net_generic(net, sit_net_id);
 143
 144        for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
 145                if (local == t->parms.iph.saddr &&
 146                    remote == t->parms.iph.daddr &&
 147                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 148                    (t->dev->flags & IFF_UP))
 149                        return t;
 150        }
 151        for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
 152                if (remote == t->parms.iph.daddr &&
 153                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 154                    (t->dev->flags & IFF_UP))
 155                        return t;
 156        }
 157        for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
 158                if (local == t->parms.iph.saddr &&
 159                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 160                    (t->dev->flags & IFF_UP))
 161                        return t;
 162        }
 163        t = rcu_dereference(sitn->tunnels_wc[0]);
 164        if ((t != NULL) && (t->dev->flags & IFF_UP))
 165                return t;
 166        return NULL;
 167}
 168
 169static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 170                struct ip_tunnel_parm *parms)
 171{
 172        __be32 remote = parms->iph.daddr;
 173        __be32 local = parms->iph.saddr;
 174        unsigned int h = 0;
 175        int prio = 0;
 176
 177        if (remote) {
 178                prio |= 2;
 179                h ^= HASH(remote);
 180        }
 181        if (local) {
 182                prio |= 1;
 183                h ^= HASH(local);
 184        }
 185        return &sitn->tunnels[prio][h];
 186}
 187
 188static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 189                struct ip_tunnel *t)
 190{
 191        return __ipip6_bucket(sitn, &t->parms);
 192}
 193
 194static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 195{
 196        struct ip_tunnel __rcu **tp;
 197        struct ip_tunnel *iter;
 198
 199        for (tp = ipip6_bucket(sitn, t);
 200             (iter = rtnl_dereference(*tp)) != NULL;
 201             tp = &iter->next) {
 202                if (t == iter) {
 203                        rcu_assign_pointer(*tp, t->next);
 204                        break;
 205                }
 206        }
 207}
 208
 209static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 210{
 211        struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 212
 213        rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 214        rcu_assign_pointer(*tp, t);
 215}
 216
 217static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 218{
 219#ifdef CONFIG_IPV6_SIT_6RD
 220        struct ip_tunnel *t = netdev_priv(dev);
 221
 222        if (t->dev == sitn->fb_tunnel_dev) {
 223                ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 224                t->ip6rd.relay_prefix = 0;
 225                t->ip6rd.prefixlen = 16;
 226                t->ip6rd.relay_prefixlen = 0;
 227        } else {
 228                struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 229                memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 230        }
 231#endif
 232}
 233
 234static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 235                struct ip_tunnel_parm *parms, int create)
 236{
 237        __be32 remote = parms->iph.daddr;
 238        __be32 local = parms->iph.saddr;
 239        struct ip_tunnel *t, *nt;
 240        struct ip_tunnel __rcu **tp;
 241        struct net_device *dev;
 242        char name[IFNAMSIZ];
 243        struct sit_net *sitn = net_generic(net, sit_net_id);
 244
 245        for (tp = __ipip6_bucket(sitn, parms);
 246            (t = rtnl_dereference(*tp)) != NULL;
 247             tp = &t->next) {
 248                if (local == t->parms.iph.saddr &&
 249                    remote == t->parms.iph.daddr &&
 250                    parms->link == t->parms.link) {
 251                        if (create)
 252                                return NULL;
 253                        else
 254                                return t;
 255                }
 256        }
 257        if (!create)
 258                goto failed;
 259
 260        if (parms->name[0])
 261                strlcpy(name, parms->name, IFNAMSIZ);
 262        else
 263                strcpy(name, "sit%d");
 264
 265        dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 266        if (dev == NULL)
 267                return NULL;
 268
 269        dev_net_set(dev, net);
 270
 271        nt = netdev_priv(dev);
 272
 273        nt->parms = *parms;
 274        if (ipip6_tunnel_init(dev) < 0)
 275                goto failed_free;
 276        ipip6_tunnel_clone_6rd(dev, sitn);
 277
 278        if (parms->i_flags & SIT_ISATAP)
 279                dev->priv_flags |= IFF_ISATAP;
 280
 281        if (register_netdevice(dev) < 0)
 282                goto failed_free;
 283
 284        strcpy(nt->parms.name, dev->name);
 285
 286        dev_hold(dev);
 287
 288        ipip6_tunnel_link(sitn, nt);
 289        return nt;
 290
 291failed_free:
 292        ipip6_dev_free(dev);
 293failed:
 294        return NULL;
 295}
 296
 297#define for_each_prl_rcu(start)                 \
 298        for (prl = rcu_dereference(start);      \
 299             prl;                               \
 300             prl = rcu_dereference(prl->next))
 301
 302static struct ip_tunnel_prl_entry *
 303__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 304{
 305        struct ip_tunnel_prl_entry *prl;
 306
 307        for_each_prl_rcu(t->prl)
 308                if (prl->addr == addr)
 309                        break;
 310        return prl;
 311
 312}
 313
 314static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 315                                struct ip_tunnel_prl __user *a)
 316{
 317        struct ip_tunnel_prl kprl, *kp;
 318        struct ip_tunnel_prl_entry *prl;
 319        unsigned int cmax, c = 0, ca, len;
 320        int ret = 0;
 321
 322        if (copy_from_user(&kprl, a, sizeof(kprl)))
 323                return -EFAULT;
 324        cmax = kprl.datalen / sizeof(kprl);
 325        if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 326                cmax = 1;
 327
 328        /* For simple GET or for root users,
 329         * we try harder to allocate.
 330         */
 331        kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 332                kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 333                NULL;
 334
 335        rcu_read_lock();
 336
 337        ca = t->prl_count < cmax ? t->prl_count : cmax;
 338
 339        if (!kp) {
 340                /* We don't try hard to allocate much memory for
 341                 * non-root users.
 342                 * For root users, retry allocating enough memory for
 343                 * the answer.
 344                 */
 345                kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 346                if (!kp) {
 347                        ret = -ENOMEM;
 348                        goto out;
 349                }
 350        }
 351
 352        c = 0;
 353        for_each_prl_rcu(t->prl) {
 354                if (c >= cmax)
 355                        break;
 356                if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 357                        continue;
 358                kp[c].addr = prl->addr;
 359                kp[c].flags = prl->flags;
 360                c++;
 361                if (kprl.addr != htonl(INADDR_ANY))
 362                        break;
 363        }
 364out:
 365        rcu_read_unlock();
 366
 367        len = sizeof(*kp) * c;
 368        ret = 0;
 369        if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 370                ret = -EFAULT;
 371
 372        kfree(kp);
 373
 374        return ret;
 375}
 376
 377static int
 378ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 379{
 380        struct ip_tunnel_prl_entry *p;
 381        int err = 0;
 382
 383        if (a->addr == htonl(INADDR_ANY))
 384                return -EINVAL;
 385
 386        ASSERT_RTNL();
 387
 388        for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 389                if (p->addr == a->addr) {
 390                        if (chg) {
 391                                p->flags = a->flags;
 392                                goto out;
 393                        }
 394                        err = -EEXIST;
 395                        goto out;
 396                }
 397        }
 398
 399        if (chg) {
 400                err = -ENXIO;
 401                goto out;
 402        }
 403
 404        p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 405        if (!p) {
 406                err = -ENOBUFS;
 407                goto out;
 408        }
 409
 410        p->next = t->prl;
 411        p->addr = a->addr;
 412        p->flags = a->flags;
 413        t->prl_count++;
 414        rcu_assign_pointer(t->prl, p);
 415out:
 416        return err;
 417}
 418
 419static void prl_list_destroy_rcu(struct rcu_head *head)
 420{
 421        struct ip_tunnel_prl_entry *p, *n;
 422
 423        p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 424        do {
 425                n = rcu_dereference_protected(p->next, 1);
 426                kfree(p);
 427                p = n;
 428        } while (p);
 429}
 430
 431static int
 432ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 433{
 434        struct ip_tunnel_prl_entry *x;
 435        struct ip_tunnel_prl_entry __rcu **p;
 436        int err = 0;
 437
 438        ASSERT_RTNL();
 439
 440        if (a && a->addr != htonl(INADDR_ANY)) {
 441                for (p = &t->prl;
 442                     (x = rtnl_dereference(*p)) != NULL;
 443                     p = &x->next) {
 444                        if (x->addr == a->addr) {
 445                                *p = x->next;
 446                                kfree_rcu(x, rcu_head);
 447                                t->prl_count--;
 448                                goto out;
 449                        }
 450                }
 451                err = -ENXIO;
 452        } else {
 453                x = rtnl_dereference(t->prl);
 454                if (x) {
 455                        t->prl_count = 0;
 456                        call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 457                        t->prl = NULL;
 458                }
 459        }
 460out:
 461        return err;
 462}
 463
 464static int
 465isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 466{
 467        struct ip_tunnel_prl_entry *p;
 468        int ok = 1;
 469
 470        rcu_read_lock();
 471        p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 472        if (p) {
 473                if (p->flags & PRL_DEFAULT)
 474                        skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 475                else
 476                        skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 477        } else {
 478                const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 479
 480                if (ipv6_addr_is_isatap(addr6) &&
 481                    (addr6->s6_addr32[3] == iph->saddr) &&
 482                    ipv6_chk_prefix(addr6, t->dev))
 483                        skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 484                else
 485                        ok = 0;
 486        }
 487        rcu_read_unlock();
 488        return ok;
 489}
 490
 491static void ipip6_tunnel_uninit(struct net_device *dev)
 492{
 493        struct net *net = dev_net(dev);
 494        struct sit_net *sitn = net_generic(net, sit_net_id);
 495
 496        if (dev == sitn->fb_tunnel_dev) {
 497                RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 498        } else {
 499                ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 500                ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 501        }
 502        dev_put(dev);
 503}
 504
 505
 506static int ipip6_err(struct sk_buff *skb, u32 info)
 507{
 508
 509/* All the routers (except for Linux) return only
 510   8 bytes of packet payload. It means, that precise relaying of
 511   ICMP in the real Internet is absolutely infeasible.
 512 */
 513        const struct iphdr *iph = (const struct iphdr *)skb->data;
 514        const int type = icmp_hdr(skb)->type;
 515        const int code = icmp_hdr(skb)->code;
 516        struct ip_tunnel *t;
 517        int err;
 518
 519        switch (type) {
 520        default:
 521        case ICMP_PARAMETERPROB:
 522                return 0;
 523
 524        case ICMP_DEST_UNREACH:
 525                switch (code) {
 526                case ICMP_SR_FAILED:
 527                case ICMP_PORT_UNREACH:
 528                        /* Impossible event. */
 529                        return 0;
 530                default:
 531                        /* All others are translated to HOST_UNREACH.
 532                           rfc2003 contains "deep thoughts" about NET_UNREACH,
 533                           I believe they are just ether pollution. --ANK
 534                         */
 535                        break;
 536                }
 537                break;
 538        case ICMP_TIME_EXCEEDED:
 539                if (code != ICMP_EXC_TTL)
 540                        return 0;
 541                break;
 542        case ICMP_REDIRECT:
 543                break;
 544        }
 545
 546        err = -ENOENT;
 547
 548        t = ipip6_tunnel_lookup(dev_net(skb->dev),
 549                                skb->dev,
 550                                iph->daddr,
 551                                iph->saddr);
 552        if (t == NULL)
 553                goto out;
 554
 555        if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 556                ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 557                                 t->dev->ifindex, 0, IPPROTO_IPV6, 0);
 558                err = 0;
 559                goto out;
 560        }
 561        if (type == ICMP_REDIRECT) {
 562                ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
 563                              IPPROTO_IPV6, 0);
 564                err = 0;
 565                goto out;
 566        }
 567
 568        if (t->parms.iph.daddr == 0)
 569                goto out;
 570
 571        err = 0;
 572        if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 573                goto out;
 574
 575        if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 576                t->err_count++;
 577        else
 578                t->err_count = 1;
 579        t->err_time = jiffies;
 580out:
 581        return err;
 582}
 583
 584static inline void ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 585{
 586        if (INET_ECN_is_ce(iph->tos))
 587                IP6_ECN_set_ce(ipv6_hdr(skb));
 588}
 589
 590static int ipip6_rcv(struct sk_buff *skb)
 591{
 592        const struct iphdr *iph;
 593        struct ip_tunnel *tunnel;
 594
 595        if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 596                goto out;
 597
 598        iph = ip_hdr(skb);
 599
 600        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 601                                     iph->saddr, iph->daddr);
 602        if (tunnel != NULL) {
 603                struct pcpu_tstats *tstats;
 604
 605                secpath_reset(skb);
 606                skb->mac_header = skb->network_header;
 607                skb_reset_network_header(skb);
 608                IPCB(skb)->flags = 0;
 609                skb->protocol = htons(ETH_P_IPV6);
 610                skb->pkt_type = PACKET_HOST;
 611
 612                if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 613                    !isatap_chksrc(skb, iph, tunnel)) {
 614                        tunnel->dev->stats.rx_errors++;
 615                        kfree_skb(skb);
 616                        return 0;
 617                }
 618
 619                tstats = this_cpu_ptr(tunnel->dev->tstats);
 620                tstats->rx_packets++;
 621                tstats->rx_bytes += skb->len;
 622
 623                __skb_tunnel_rx(skb, tunnel->dev);
 624
 625                ipip6_ecn_decapsulate(iph, skb);
 626
 627                netif_rx(skb);
 628
 629                return 0;
 630        }
 631
 632        /* no tunnel matched,  let upstream know, ipsec may handle it */
 633        return 1;
 634out:
 635        kfree_skb(skb);
 636        return 0;
 637}
 638
 639/*
 640 * Returns the embedded IPv4 address if the IPv6 address
 641 * comes from 6rd / 6to4 (RFC 3056) addr space.
 642 */
 643static inline
 644__be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 645{
 646        __be32 dst = 0;
 647
 648#ifdef CONFIG_IPV6_SIT_6RD
 649        if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 650                              tunnel->ip6rd.prefixlen)) {
 651                unsigned int pbw0, pbi0;
 652                int pbi1;
 653                u32 d;
 654
 655                pbw0 = tunnel->ip6rd.prefixlen >> 5;
 656                pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 657
 658                d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 659                    tunnel->ip6rd.relay_prefixlen;
 660
 661                pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 662                if (pbi1 > 0)
 663                        d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 664                             (32 - pbi1);
 665
 666                dst = tunnel->ip6rd.relay_prefix | htonl(d);
 667        }
 668#else
 669        if (v6dst->s6_addr16[0] == htons(0x2002)) {
 670                /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 671                memcpy(&dst, &v6dst->s6_addr16[1], 4);
 672        }
 673#endif
 674        return dst;
 675}
 676
 677/*
 678 *      This function assumes it is being called from dev_queue_xmit()
 679 *      and that skb is filled properly by that function.
 680 */
 681
 682static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 683                                     struct net_device *dev)
 684{
 685        struct ip_tunnel *tunnel = netdev_priv(dev);
 686        struct pcpu_tstats *tstats;
 687        const struct iphdr  *tiph = &tunnel->parms.iph;
 688        const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 689        u8     tos = tunnel->parms.iph.tos;
 690        __be16 df = tiph->frag_off;
 691        struct rtable *rt;                      /* Route to the other host */
 692        struct net_device *tdev;                /* Device to other host */
 693        struct iphdr  *iph;                     /* Our new IP header */
 694        unsigned int max_headroom;              /* The extra header space needed */
 695        __be32 dst = tiph->daddr;
 696        struct flowi4 fl4;
 697        int    mtu;
 698        const struct in6_addr *addr6;
 699        int addr_type;
 700
 701        if (skb->protocol != htons(ETH_P_IPV6))
 702                goto tx_error;
 703
 704        if (tos == 1)
 705                tos = ipv6_get_dsfield(iph6);
 706
 707        /* ISATAP (RFC4214) - must come before 6to4 */
 708        if (dev->priv_flags & IFF_ISATAP) {
 709                struct neighbour *neigh = NULL;
 710                bool do_tx_error = false;
 711
 712                if (skb_dst(skb))
 713                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 714
 715                if (neigh == NULL) {
 716                        net_dbg_ratelimited("sit: nexthop == NULL\n");
 717                        goto tx_error;
 718                }
 719
 720                addr6 = (const struct in6_addr *)&neigh->primary_key;
 721                addr_type = ipv6_addr_type(addr6);
 722
 723                if ((addr_type & IPV6_ADDR_UNICAST) &&
 724                     ipv6_addr_is_isatap(addr6))
 725                        dst = addr6->s6_addr32[3];
 726                else
 727                        do_tx_error = true;
 728
 729                neigh_release(neigh);
 730                if (do_tx_error)
 731                        goto tx_error;
 732        }
 733
 734        if (!dst)
 735                dst = try_6rd(&iph6->daddr, tunnel);
 736
 737        if (!dst) {
 738                struct neighbour *neigh = NULL;
 739                bool do_tx_error = false;
 740
 741                if (skb_dst(skb))
 742                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 743
 744                if (neigh == NULL) {
 745                        net_dbg_ratelimited("sit: nexthop == NULL\n");
 746                        goto tx_error;
 747                }
 748
 749                addr6 = (const struct in6_addr *)&neigh->primary_key;
 750                addr_type = ipv6_addr_type(addr6);
 751
 752                if (addr_type == IPV6_ADDR_ANY) {
 753                        addr6 = &ipv6_hdr(skb)->daddr;
 754                        addr_type = ipv6_addr_type(addr6);
 755                }
 756
 757                if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 758                        dst = addr6->s6_addr32[3];
 759                else
 760                        do_tx_error = true;
 761
 762                neigh_release(neigh);
 763                if (do_tx_error)
 764                        goto tx_error;
 765        }
 766
 767        rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 768                                   dst, tiph->saddr,
 769                                   0, 0,
 770                                   IPPROTO_IPV6, RT_TOS(tos),
 771                                   tunnel->parms.link);
 772        if (IS_ERR(rt)) {
 773                dev->stats.tx_carrier_errors++;
 774                goto tx_error_icmp;
 775        }
 776        if (rt->rt_type != RTN_UNICAST) {
 777                ip_rt_put(rt);
 778                dev->stats.tx_carrier_errors++;
 779                goto tx_error_icmp;
 780        }
 781        tdev = rt->dst.dev;
 782
 783        if (tdev == dev) {
 784                ip_rt_put(rt);
 785                dev->stats.collisions++;
 786                goto tx_error;
 787        }
 788
 789        if (df) {
 790                mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 791
 792                if (mtu < 68) {
 793                        dev->stats.collisions++;
 794                        ip_rt_put(rt);
 795                        goto tx_error;
 796                }
 797
 798                if (mtu < IPV6_MIN_MTU) {
 799                        mtu = IPV6_MIN_MTU;
 800                        df = 0;
 801                }
 802
 803                if (tunnel->parms.iph.daddr && skb_dst(skb))
 804                        skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 805
 806                if (skb->len > mtu) {
 807                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 808                        ip_rt_put(rt);
 809                        goto tx_error;
 810                }
 811        }
 812
 813        if (tunnel->err_count > 0) {
 814                if (time_before(jiffies,
 815                                tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 816                        tunnel->err_count--;
 817                        dst_link_failure(skb);
 818                } else
 819                        tunnel->err_count = 0;
 820        }
 821
 822        /*
 823         * Okay, now see if we can stuff it in the buffer as-is.
 824         */
 825        max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 826
 827        if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 828            (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 829                struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 830                if (!new_skb) {
 831                        ip_rt_put(rt);
 832                        dev->stats.tx_dropped++;
 833                        dev_kfree_skb(skb);
 834                        return NETDEV_TX_OK;
 835                }
 836                if (skb->sk)
 837                        skb_set_owner_w(new_skb, skb->sk);
 838                dev_kfree_skb(skb);
 839                skb = new_skb;
 840                iph6 = ipv6_hdr(skb);
 841        }
 842
 843        skb->transport_header = skb->network_header;
 844        skb_push(skb, sizeof(struct iphdr));
 845        skb_reset_network_header(skb);
 846        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 847        IPCB(skb)->flags = 0;
 848        skb_dst_drop(skb);
 849        skb_dst_set(skb, &rt->dst);
 850
 851        /*
 852         *      Push down and install the IPIP header.
 853         */
 854
 855        iph                     =       ip_hdr(skb);
 856        iph->version            =       4;
 857        iph->ihl                =       sizeof(struct iphdr)>>2;
 858        iph->frag_off           =       df;
 859        iph->protocol           =       IPPROTO_IPV6;
 860        iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 861        iph->daddr              =       fl4.daddr;
 862        iph->saddr              =       fl4.saddr;
 863
 864        if ((iph->ttl = tiph->ttl) == 0)
 865                iph->ttl        =       iph6->hop_limit;
 866
 867        nf_reset(skb);
 868        tstats = this_cpu_ptr(dev->tstats);
 869        __IPTUNNEL_XMIT(tstats, &dev->stats);
 870        return NETDEV_TX_OK;
 871
 872tx_error_icmp:
 873        dst_link_failure(skb);
 874tx_error:
 875        dev->stats.tx_errors++;
 876        dev_kfree_skb(skb);
 877        return NETDEV_TX_OK;
 878}
 879
 880static void ipip6_tunnel_bind_dev(struct net_device *dev)
 881{
 882        struct net_device *tdev = NULL;
 883        struct ip_tunnel *tunnel;
 884        const struct iphdr *iph;
 885        struct flowi4 fl4;
 886
 887        tunnel = netdev_priv(dev);
 888        iph = &tunnel->parms.iph;
 889
 890        if (iph->daddr) {
 891                struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
 892                                                          iph->daddr, iph->saddr,
 893                                                          0, 0,
 894                                                          IPPROTO_IPV6,
 895                                                          RT_TOS(iph->tos),
 896                                                          tunnel->parms.link);
 897
 898                if (!IS_ERR(rt)) {
 899                        tdev = rt->dst.dev;
 900                        ip_rt_put(rt);
 901                }
 902                dev->flags |= IFF_POINTOPOINT;
 903        }
 904
 905        if (!tdev && tunnel->parms.link)
 906                tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 907
 908        if (tdev) {
 909                dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 910                dev->mtu = tdev->mtu - sizeof(struct iphdr);
 911                if (dev->mtu < IPV6_MIN_MTU)
 912                        dev->mtu = IPV6_MIN_MTU;
 913        }
 914        dev->iflink = tunnel->parms.link;
 915}
 916
 917static int
 918ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 919{
 920        int err = 0;
 921        struct ip_tunnel_parm p;
 922        struct ip_tunnel_prl prl;
 923        struct ip_tunnel *t;
 924        struct net *net = dev_net(dev);
 925        struct sit_net *sitn = net_generic(net, sit_net_id);
 926#ifdef CONFIG_IPV6_SIT_6RD
 927        struct ip_tunnel_6rd ip6rd;
 928#endif
 929
 930        switch (cmd) {
 931        case SIOCGETTUNNEL:
 932#ifdef CONFIG_IPV6_SIT_6RD
 933        case SIOCGET6RD:
 934#endif
 935                t = NULL;
 936                if (dev == sitn->fb_tunnel_dev) {
 937                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 938                                err = -EFAULT;
 939                                break;
 940                        }
 941                        t = ipip6_tunnel_locate(net, &p, 0);
 942                }
 943                if (t == NULL)
 944                        t = netdev_priv(dev);
 945
 946                err = -EFAULT;
 947                if (cmd == SIOCGETTUNNEL) {
 948                        memcpy(&p, &t->parms, sizeof(p));
 949                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
 950                                         sizeof(p)))
 951                                goto done;
 952#ifdef CONFIG_IPV6_SIT_6RD
 953                } else {
 954                        ip6rd.prefix = t->ip6rd.prefix;
 955                        ip6rd.relay_prefix = t->ip6rd.relay_prefix;
 956                        ip6rd.prefixlen = t->ip6rd.prefixlen;
 957                        ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
 958                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
 959                                         sizeof(ip6rd)))
 960                                goto done;
 961#endif
 962                }
 963                err = 0;
 964                break;
 965
 966        case SIOCADDTUNNEL:
 967        case SIOCCHGTUNNEL:
 968                err = -EPERM;
 969                if (!capable(CAP_NET_ADMIN))
 970                        goto done;
 971
 972                err = -EFAULT;
 973                if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 974                        goto done;
 975
 976                err = -EINVAL;
 977                if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 978                    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 979                        goto done;
 980                if (p.iph.ttl)
 981                        p.iph.frag_off |= htons(IP_DF);
 982
 983                t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 984
 985                if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 986                        if (t != NULL) {
 987                                if (t->dev != dev) {
 988                                        err = -EEXIST;
 989                                        break;
 990                                }
 991                        } else {
 992                                if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 993                                    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 994                                        err = -EINVAL;
 995                                        break;
 996                                }
 997                                t = netdev_priv(dev);
 998                                ipip6_tunnel_unlink(sitn, t);
 999                                synchronize_net();
1000                                t->parms.iph.saddr = p.iph.saddr;
1001                                t->parms.iph.daddr = p.iph.daddr;
1002                                memcpy(dev->dev_addr, &p.iph.saddr, 4);
1003                                memcpy(dev->broadcast, &p.iph.daddr, 4);
1004                                ipip6_tunnel_link(sitn, t);
1005                                netdev_state_change(dev);
1006                        }
1007                }
1008
1009                if (t) {
1010                        err = 0;
1011                        if (cmd == SIOCCHGTUNNEL) {
1012                                t->parms.iph.ttl = p.iph.ttl;
1013                                t->parms.iph.tos = p.iph.tos;
1014                                if (t->parms.link != p.link) {
1015                                        t->parms.link = p.link;
1016                                        ipip6_tunnel_bind_dev(dev);
1017                                        netdev_state_change(dev);
1018                                }
1019                        }
1020                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1021                                err = -EFAULT;
1022                } else
1023                        err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1024                break;
1025
1026        case SIOCDELTUNNEL:
1027                err = -EPERM;
1028                if (!capable(CAP_NET_ADMIN))
1029                        goto done;
1030
1031                if (dev == sitn->fb_tunnel_dev) {
1032                        err = -EFAULT;
1033                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1034                                goto done;
1035                        err = -ENOENT;
1036                        if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1037                                goto done;
1038                        err = -EPERM;
1039                        if (t == netdev_priv(sitn->fb_tunnel_dev))
1040                                goto done;
1041                        dev = t->dev;
1042                }
1043                unregister_netdevice(dev);
1044                err = 0;
1045                break;
1046
1047        case SIOCGETPRL:
1048                err = -EINVAL;
1049                if (dev == sitn->fb_tunnel_dev)
1050                        goto done;
1051                err = -ENOENT;
1052                if (!(t = netdev_priv(dev)))
1053                        goto done;
1054                err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1055                break;
1056
1057        case SIOCADDPRL:
1058        case SIOCDELPRL:
1059        case SIOCCHGPRL:
1060                err = -EPERM;
1061                if (!capable(CAP_NET_ADMIN))
1062                        goto done;
1063                err = -EINVAL;
1064                if (dev == sitn->fb_tunnel_dev)
1065                        goto done;
1066                err = -EFAULT;
1067                if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1068                        goto done;
1069                err = -ENOENT;
1070                if (!(t = netdev_priv(dev)))
1071                        goto done;
1072
1073                switch (cmd) {
1074                case SIOCDELPRL:
1075                        err = ipip6_tunnel_del_prl(t, &prl);
1076                        break;
1077                case SIOCADDPRL:
1078                case SIOCCHGPRL:
1079                        err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1080                        break;
1081                }
1082                netdev_state_change(dev);
1083                break;
1084
1085#ifdef CONFIG_IPV6_SIT_6RD
1086        case SIOCADD6RD:
1087        case SIOCCHG6RD:
1088        case SIOCDEL6RD:
1089                err = -EPERM;
1090                if (!capable(CAP_NET_ADMIN))
1091                        goto done;
1092
1093                err = -EFAULT;
1094                if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1095                                   sizeof(ip6rd)))
1096                        goto done;
1097
1098                t = netdev_priv(dev);
1099
1100                if (cmd != SIOCDEL6RD) {
1101                        struct in6_addr prefix;
1102                        __be32 relay_prefix;
1103
1104                        err = -EINVAL;
1105                        if (ip6rd.relay_prefixlen > 32 ||
1106                            ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1107                                goto done;
1108
1109                        ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1110                                         ip6rd.prefixlen);
1111                        if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1112                                goto done;
1113                        if (ip6rd.relay_prefixlen)
1114                                relay_prefix = ip6rd.relay_prefix &
1115                                               htonl(0xffffffffUL <<
1116                                                     (32 - ip6rd.relay_prefixlen));
1117                        else
1118                                relay_prefix = 0;
1119                        if (relay_prefix != ip6rd.relay_prefix)
1120                                goto done;
1121
1122                        t->ip6rd.prefix = prefix;
1123                        t->ip6rd.relay_prefix = relay_prefix;
1124                        t->ip6rd.prefixlen = ip6rd.prefixlen;
1125                        t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1126                } else
1127                        ipip6_tunnel_clone_6rd(dev, sitn);
1128
1129                err = 0;
1130                break;
1131#endif
1132
1133        default:
1134                err = -EINVAL;
1135        }
1136
1137done:
1138        return err;
1139}
1140
1141static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1142{
1143        if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1144                return -EINVAL;
1145        dev->mtu = new_mtu;
1146        return 0;
1147}
1148
1149static const struct net_device_ops ipip6_netdev_ops = {
1150        .ndo_uninit     = ipip6_tunnel_uninit,
1151        .ndo_start_xmit = ipip6_tunnel_xmit,
1152        .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1153        .ndo_change_mtu = ipip6_tunnel_change_mtu,
1154        .ndo_get_stats64= ipip6_get_stats64,
1155};
1156
1157static void ipip6_dev_free(struct net_device *dev)
1158{
1159        free_percpu(dev->tstats);
1160        free_netdev(dev);
1161}
1162
1163static void ipip6_tunnel_setup(struct net_device *dev)
1164{
1165        dev->netdev_ops         = &ipip6_netdev_ops;
1166        dev->destructor         = ipip6_dev_free;
1167
1168        dev->type               = ARPHRD_SIT;
1169        dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1170        dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1171        dev->flags              = IFF_NOARP;
1172        dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1173        dev->iflink             = 0;
1174        dev->addr_len           = 4;
1175        dev->features           |= NETIF_F_NETNS_LOCAL;
1176        dev->features           |= NETIF_F_LLTX;
1177}
1178
1179static int ipip6_tunnel_init(struct net_device *dev)
1180{
1181        struct ip_tunnel *tunnel = netdev_priv(dev);
1182
1183        tunnel->dev = dev;
1184
1185        memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1186        memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1187
1188        ipip6_tunnel_bind_dev(dev);
1189        dev->tstats = alloc_percpu(struct pcpu_tstats);
1190        if (!dev->tstats)
1191                return -ENOMEM;
1192
1193        return 0;
1194}
1195
1196static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1197{
1198        struct ip_tunnel *tunnel = netdev_priv(dev);
1199        struct iphdr *iph = &tunnel->parms.iph;
1200        struct net *net = dev_net(dev);
1201        struct sit_net *sitn = net_generic(net, sit_net_id);
1202
1203        tunnel->dev = dev;
1204        strcpy(tunnel->parms.name, dev->name);
1205
1206        iph->version            = 4;
1207        iph->protocol           = IPPROTO_IPV6;
1208        iph->ihl                = 5;
1209        iph->ttl                = 64;
1210
1211        dev->tstats = alloc_percpu(struct pcpu_tstats);
1212        if (!dev->tstats)
1213                return -ENOMEM;
1214        dev_hold(dev);
1215        rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1216        return 0;
1217}
1218
1219static struct xfrm_tunnel sit_handler __read_mostly = {
1220        .handler        =       ipip6_rcv,
1221        .err_handler    =       ipip6_err,
1222        .priority       =       1,
1223};
1224
1225static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1226{
1227        int prio;
1228
1229        for (prio = 1; prio < 4; prio++) {
1230                int h;
1231                for (h = 0; h < HASH_SIZE; h++) {
1232                        struct ip_tunnel *t;
1233
1234                        t = rtnl_dereference(sitn->tunnels[prio][h]);
1235                        while (t != NULL) {
1236                                unregister_netdevice_queue(t->dev, head);
1237                                t = rtnl_dereference(t->next);
1238                        }
1239                }
1240        }
1241}
1242
1243static int __net_init sit_init_net(struct net *net)
1244{
1245        struct sit_net *sitn = net_generic(net, sit_net_id);
1246        struct ip_tunnel *t;
1247        int err;
1248
1249        sitn->tunnels[0] = sitn->tunnels_wc;
1250        sitn->tunnels[1] = sitn->tunnels_l;
1251        sitn->tunnels[2] = sitn->tunnels_r;
1252        sitn->tunnels[3] = sitn->tunnels_r_l;
1253
1254        sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1255                                           ipip6_tunnel_setup);
1256        if (!sitn->fb_tunnel_dev) {
1257                err = -ENOMEM;
1258                goto err_alloc_dev;
1259        }
1260        dev_net_set(sitn->fb_tunnel_dev, net);
1261
1262        err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1263        if (err)
1264                goto err_dev_free;
1265
1266        ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1267
1268        if ((err = register_netdev(sitn->fb_tunnel_dev)))
1269                goto err_reg_dev;
1270
1271        t = netdev_priv(sitn->fb_tunnel_dev);
1272
1273        strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1274        return 0;
1275
1276err_reg_dev:
1277        dev_put(sitn->fb_tunnel_dev);
1278err_dev_free:
1279        ipip6_dev_free(sitn->fb_tunnel_dev);
1280err_alloc_dev:
1281        return err;
1282}
1283
1284static void __net_exit sit_exit_net(struct net *net)
1285{
1286        struct sit_net *sitn = net_generic(net, sit_net_id);
1287        LIST_HEAD(list);
1288
1289        rtnl_lock();
1290        sit_destroy_tunnels(sitn, &list);
1291        unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1292        unregister_netdevice_many(&list);
1293        rtnl_unlock();
1294}
1295
1296static struct pernet_operations sit_net_ops = {
1297        .init = sit_init_net,
1298        .exit = sit_exit_net,
1299        .id   = &sit_net_id,
1300        .size = sizeof(struct sit_net),
1301};
1302
1303static void __exit sit_cleanup(void)
1304{
1305        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1306
1307        unregister_pernet_device(&sit_net_ops);
1308        rcu_barrier(); /* Wait for completion of call_rcu()'s */
1309}
1310
1311static int __init sit_init(void)
1312{
1313        int err;
1314
1315        pr_info("IPv6 over IPv4 tunneling driver\n");
1316
1317        err = register_pernet_device(&sit_net_ops);
1318        if (err < 0)
1319                return err;
1320        err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1321        if (err < 0) {
1322                unregister_pernet_device(&sit_net_ops);
1323                pr_info("%s: can't add protocol\n", __func__);
1324        }
1325        return err;
1326}
1327
1328module_init(sit_init);
1329module_exit(sit_cleanup);
1330MODULE_LICENSE("GPL");
1331MODULE_ALIAS_NETDEV("sit0");
1332
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