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#include <linux/module.h>
  21#include <linux/capability.h>
  22#include <linux/errno.h>
  23#include <linux/types.h>
  24#include <linux/socket.h>
  25#include <linux/sockios.h>
  26#include <linux/net.h>
  27#include <linux/in6.h>
  28#include <linux/netdevice.h>
  29#include <linux/if_arp.h>
  30#include <linux/icmp.h>
  31#include <asm/uaccess.h>
  32#include <linux/init.h>
  33#include <linux/netfilter_ipv4.h>
  34#include <linux/if_ether.h>
  35
  36#include <net/sock.h>
  37#include <net/snmp.h>
  38
  39#include <net/ipv6.h>
  40#include <net/protocol.h>
  41#include <net/transp_v6.h>
  42#include <net/ip6_fib.h>
  43#include <net/ip6_route.h>
  44#include <net/ndisc.h>
  45#include <net/addrconf.h>
  46#include <net/ip.h>
  47#include <net/udp.h>
  48#include <net/icmp.h>
  49#include <net/ipip.h>
  50#include <net/inet_ecn.h>
  51#include <net/xfrm.h>
  52#include <net/dsfield.h>
  53#include <net/net_namespace.h>
  54#include <net/netns/generic.h>
  55
  56/*
  57   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  58
  59   For comments look at net/ipv4/ip_gre.c --ANK
  60 */
  61
  62#define HASH_SIZE  16
  63#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  64
  65static void ipip6_fb_tunnel_init(struct net_device *dev);
  66static void ipip6_tunnel_init(struct net_device *dev);
  67static void ipip6_tunnel_setup(struct net_device *dev);
  68
  69static int sit_net_id __read_mostly;
  70struct sit_net {
  71        struct ip_tunnel *tunnels_r_l[HASH_SIZE];
  72        struct ip_tunnel *tunnels_r[HASH_SIZE];
  73        struct ip_tunnel *tunnels_l[HASH_SIZE];
  74        struct ip_tunnel *tunnels_wc[1];
  75        struct ip_tunnel **tunnels[4];
  76
  77        struct net_device *fb_tunnel_dev;
  78};
  79
  80/*
  81 * Locking : hash tables are protected by RCU and a spinlock
  82 */
  83static DEFINE_SPINLOCK(ipip6_lock);
  84
  85#define for_each_ip_tunnel_rcu(start) \
  86        for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
  87
  88/*
  89 * Must be invoked with rcu_read_lock
  90 */
  91static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
  92                struct net_device *dev, __be32 remote, __be32 local)
  93{
  94        unsigned h0 = HASH(remote);
  95        unsigned h1 = HASH(local);
  96        struct ip_tunnel *t;
  97        struct sit_net *sitn = net_generic(net, sit_net_id);
  98
  99        for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
 100                if (local == t->parms.iph.saddr &&
 101                    remote == t->parms.iph.daddr &&
 102                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 103                    (t->dev->flags & IFF_UP))
 104                        return t;
 105        }
 106        for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
 107                if (remote == t->parms.iph.daddr &&
 108                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 109                    (t->dev->flags & IFF_UP))
 110                        return t;
 111        }
 112        for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
 113                if (local == t->parms.iph.saddr &&
 114                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 115                    (t->dev->flags & IFF_UP))
 116                        return t;
 117        }
 118        t = rcu_dereference(sitn->tunnels_wc[0]);
 119        if ((t != NULL) && (t->dev->flags & IFF_UP))
 120                return t;
 121        return NULL;
 122}
 123
 124static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
 125                struct ip_tunnel_parm *parms)
 126{
 127        __be32 remote = parms->iph.daddr;
 128        __be32 local = parms->iph.saddr;
 129        unsigned h = 0;
 130        int prio = 0;
 131
 132        if (remote) {
 133                prio |= 2;
 134                h ^= HASH(remote);
 135        }
 136        if (local) {
 137                prio |= 1;
 138                h ^= HASH(local);
 139        }
 140        return &sitn->tunnels[prio][h];
 141}
 142
 143static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
 144                struct ip_tunnel *t)
 145{
 146        return __ipip6_bucket(sitn, &t->parms);
 147}
 148
 149static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 150{
 151        struct ip_tunnel **tp;
 152
 153        for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
 154                if (t == *tp) {
 155                        spin_lock_bh(&ipip6_lock);
 156                        *tp = t->next;
 157                        spin_unlock_bh(&ipip6_lock);
 158                        break;
 159                }
 160        }
 161}
 162
 163static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 164{
 165        struct ip_tunnel **tp = ipip6_bucket(sitn, t);
 166
 167        spin_lock_bh(&ipip6_lock);
 168        t->next = *tp;
 169        rcu_assign_pointer(*tp, t);
 170        spin_unlock_bh(&ipip6_lock);
 171}
 172
 173static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 174{
 175#ifdef CONFIG_IPV6_SIT_6RD
 176        struct ip_tunnel *t = netdev_priv(dev);
 177
 178        if (t->dev == sitn->fb_tunnel_dev) {
 179                ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 180                t->ip6rd.relay_prefix = 0;
 181                t->ip6rd.prefixlen = 16;
 182                t->ip6rd.relay_prefixlen = 0;
 183        } else {
 184                struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 185                memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 186        }
 187#endif
 188}
 189
 190static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
 191                struct ip_tunnel_parm *parms, int create)
 192{
 193        __be32 remote = parms->iph.daddr;
 194        __be32 local = parms->iph.saddr;
 195        struct ip_tunnel *t, **tp, *nt;
 196        struct net_device *dev;
 197        char name[IFNAMSIZ];
 198        struct sit_net *sitn = net_generic(net, sit_net_id);
 199
 200        for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
 201                if (local == t->parms.iph.saddr &&
 202                    remote == t->parms.iph.daddr &&
 203                    parms->link == t->parms.link) {
 204                        if (create)
 205                                return NULL;
 206                        else
 207                                return t;
 208                }
 209        }
 210        if (!create)
 211                goto failed;
 212
 213        if (parms->name[0])
 214                strlcpy(name, parms->name, IFNAMSIZ);
 215        else
 216                sprintf(name, "sit%%d");
 217
 218        dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 219        if (dev == NULL)
 220                return NULL;
 221
 222        dev_net_set(dev, net);
 223
 224        if (strchr(name, '%')) {
 225                if (dev_alloc_name(dev, name) < 0)
 226                        goto failed_free;
 227        }
 228
 229        nt = netdev_priv(dev);
 230
 231        nt->parms = *parms;
 232        ipip6_tunnel_init(dev);
 233        ipip6_tunnel_clone_6rd(dev, sitn);
 234
 235        if (parms->i_flags & SIT_ISATAP)
 236                dev->priv_flags |= IFF_ISATAP;
 237
 238        if (register_netdevice(dev) < 0)
 239                goto failed_free;
 240
 241        dev_hold(dev);
 242
 243        ipip6_tunnel_link(sitn, nt);
 244        return nt;
 245
 246failed_free:
 247        free_netdev(dev);
 248failed:
 249        return NULL;
 250}
 251
 252static DEFINE_SPINLOCK(ipip6_prl_lock);
 253
 254#define for_each_prl_rcu(start)                 \
 255        for (prl = rcu_dereference(start);      \
 256             prl;                               \
 257             prl = rcu_dereference(prl->next))
 258
 259static struct ip_tunnel_prl_entry *
 260__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 261{
 262        struct ip_tunnel_prl_entry *prl;
 263
 264        for_each_prl_rcu(t->prl)
 265                if (prl->addr == addr)
 266                        break;
 267        return prl;
 268
 269}
 270
 271static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 272                                struct ip_tunnel_prl __user *a)
 273{
 274        struct ip_tunnel_prl kprl, *kp;
 275        struct ip_tunnel_prl_entry *prl;
 276        unsigned int cmax, c = 0, ca, len;
 277        int ret = 0;
 278
 279        if (copy_from_user(&kprl, a, sizeof(kprl)))
 280                return -EFAULT;
 281        cmax = kprl.datalen / sizeof(kprl);
 282        if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 283                cmax = 1;
 284
 285        /* For simple GET or for root users,
 286         * we try harder to allocate.
 287         */
 288        kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 289                kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 290                NULL;
 291
 292        rcu_read_lock();
 293
 294        ca = t->prl_count < cmax ? t->prl_count : cmax;
 295
 296        if (!kp) {
 297                /* We don't try hard to allocate much memory for
 298                 * non-root users.
 299                 * For root users, retry allocating enough memory for
 300                 * the answer.
 301                 */
 302                kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 303                if (!kp) {
 304                        ret = -ENOMEM;
 305                        goto out;
 306                }
 307        }
 308
 309        c = 0;
 310        for_each_prl_rcu(t->prl) {
 311                if (c >= cmax)
 312                        break;
 313                if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 314                        continue;
 315                kp[c].addr = prl->addr;
 316                kp[c].flags = prl->flags;
 317                c++;
 318                if (kprl.addr != htonl(INADDR_ANY))
 319                        break;
 320        }
 321out:
 322        rcu_read_unlock();
 323
 324        len = sizeof(*kp) * c;
 325        ret = 0;
 326        if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 327                ret = -EFAULT;
 328
 329        kfree(kp);
 330
 331        return ret;
 332}
 333
 334static int
 335ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 336{
 337        struct ip_tunnel_prl_entry *p;
 338        int err = 0;
 339
 340        if (a->addr == htonl(INADDR_ANY))
 341                return -EINVAL;
 342
 343        spin_lock(&ipip6_prl_lock);
 344
 345        for (p = t->prl; p; p = p->next) {
 346                if (p->addr == a->addr) {
 347                        if (chg) {
 348                                p->flags = a->flags;
 349                                goto out;
 350                        }
 351                        err = -EEXIST;
 352                        goto out;
 353                }
 354        }
 355
 356        if (chg) {
 357                err = -ENXIO;
 358                goto out;
 359        }
 360
 361        p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 362        if (!p) {
 363                err = -ENOBUFS;
 364                goto out;
 365        }
 366
 367        INIT_RCU_HEAD(&p->rcu_head);
 368        p->next = t->prl;
 369        p->addr = a->addr;
 370        p->flags = a->flags;
 371        t->prl_count++;
 372        rcu_assign_pointer(t->prl, p);
 373out:
 374        spin_unlock(&ipip6_prl_lock);
 375        return err;
 376}
 377
 378static void prl_entry_destroy_rcu(struct rcu_head *head)
 379{
 380        kfree(container_of(head, struct ip_tunnel_prl_entry, rcu_head));
 381}
 382
 383static void prl_list_destroy_rcu(struct rcu_head *head)
 384{
 385        struct ip_tunnel_prl_entry *p, *n;
 386
 387        p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 388        do {
 389                n = p->next;
 390                kfree(p);
 391                p = n;
 392        } while (p);
 393}
 394
 395static int
 396ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 397{
 398        struct ip_tunnel_prl_entry *x, **p;
 399        int err = 0;
 400
 401        spin_lock(&ipip6_prl_lock);
 402
 403        if (a && a->addr != htonl(INADDR_ANY)) {
 404                for (p = &t->prl; *p; p = &(*p)->next) {
 405                        if ((*p)->addr == a->addr) {
 406                                x = *p;
 407                                *p = x->next;
 408                                call_rcu(&x->rcu_head, prl_entry_destroy_rcu);
 409                                t->prl_count--;
 410                                goto out;
 411                        }
 412                }
 413                err = -ENXIO;
 414        } else {
 415                if (t->prl) {
 416                        t->prl_count = 0;
 417                        x = t->prl;
 418                        call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 419                        t->prl = NULL;
 420                }
 421        }
 422out:
 423        spin_unlock(&ipip6_prl_lock);
 424        return err;
 425}
 426
 427static int
 428isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
 429{
 430        struct ip_tunnel_prl_entry *p;
 431        int ok = 1;
 432
 433        rcu_read_lock();
 434        p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 435        if (p) {
 436                if (p->flags & PRL_DEFAULT)
 437                        skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 438                else
 439                        skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 440        } else {
 441                struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 442                if (ipv6_addr_is_isatap(addr6) &&
 443                    (addr6->s6_addr32[3] == iph->saddr) &&
 444                    ipv6_chk_prefix(addr6, t->dev))
 445                        skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 446                else
 447                        ok = 0;
 448        }
 449        rcu_read_unlock();
 450        return ok;
 451}
 452
 453static void ipip6_tunnel_uninit(struct net_device *dev)
 454{
 455        struct net *net = dev_net(dev);
 456        struct sit_net *sitn = net_generic(net, sit_net_id);
 457
 458        if (dev == sitn->fb_tunnel_dev) {
 459                spin_lock_bh(&ipip6_lock);
 460                sitn->tunnels_wc[0] = NULL;
 461                spin_unlock_bh(&ipip6_lock);
 462                dev_put(dev);
 463        } else {
 464                ipip6_tunnel_unlink(sitn, netdev_priv(dev));
 465                ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
 466                dev_put(dev);
 467        }
 468}
 469
 470
 471static int ipip6_err(struct sk_buff *skb, u32 info)
 472{
 473
 474/* All the routers (except for Linux) return only
 475   8 bytes of packet payload. It means, that precise relaying of
 476   ICMP in the real Internet is absolutely infeasible.
 477 */
 478        struct iphdr *iph = (struct iphdr*)skb->data;
 479        const int type = icmp_hdr(skb)->type;
 480        const int code = icmp_hdr(skb)->code;
 481        struct ip_tunnel *t;
 482        int err;
 483
 484        switch (type) {
 485        default:
 486        case ICMP_PARAMETERPROB:
 487                return 0;
 488
 489        case ICMP_DEST_UNREACH:
 490                switch (code) {
 491                case ICMP_SR_FAILED:
 492                case ICMP_PORT_UNREACH:
 493                        /* Impossible event. */
 494                        return 0;
 495                case ICMP_FRAG_NEEDED:
 496                        /* Soft state for pmtu is maintained by IP core. */
 497                        return 0;
 498                default:
 499                        /* All others are translated to HOST_UNREACH.
 500                           rfc2003 contains "deep thoughts" about NET_UNREACH,
 501                           I believe they are just ether pollution. --ANK
 502                         */
 503                        break;
 504                }
 505                break;
 506        case ICMP_TIME_EXCEEDED:
 507                if (code != ICMP_EXC_TTL)
 508                        return 0;
 509                break;
 510        }
 511
 512        err = -ENOENT;
 513
 514        rcu_read_lock();
 515        t = ipip6_tunnel_lookup(dev_net(skb->dev),
 516                                skb->dev,
 517                                iph->daddr,
 518                                iph->saddr);
 519        if (t == NULL || t->parms.iph.daddr == 0)
 520                goto out;
 521
 522        err = 0;
 523        if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 524                goto out;
 525
 526        if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 527                t->err_count++;
 528        else
 529                t->err_count = 1;
 530        t->err_time = jiffies;
 531out:
 532        rcu_read_unlock();
 533        return err;
 534}
 535
 536static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 537{
 538        if (INET_ECN_is_ce(iph->tos))
 539                IP6_ECN_set_ce(ipv6_hdr(skb));
 540}
 541
 542static int ipip6_rcv(struct sk_buff *skb)
 543{
 544        struct iphdr *iph;
 545        struct ip_tunnel *tunnel;
 546
 547        if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
 548                goto out;
 549
 550        iph = ip_hdr(skb);
 551
 552        rcu_read_lock();
 553        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 554                                     iph->saddr, iph->daddr);
 555        if (tunnel != NULL) {
 556                secpath_reset(skb);
 557                skb->mac_header = skb->network_header;
 558                skb_reset_network_header(skb);
 559                IPCB(skb)->flags = 0;
 560                skb->protocol = htons(ETH_P_IPV6);
 561                skb->pkt_type = PACKET_HOST;
 562
 563                if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
 564                    !isatap_chksrc(skb, iph, tunnel)) {
 565                        tunnel->dev->stats.rx_errors++;
 566                        rcu_read_unlock();
 567                        kfree_skb(skb);
 568                        return 0;
 569                }
 570                tunnel->dev->stats.rx_packets++;
 571                tunnel->dev->stats.rx_bytes += skb->len;
 572                skb->dev = tunnel->dev;
 573                skb_dst_drop(skb);
 574                nf_reset(skb);
 575                ipip6_ecn_decapsulate(iph, skb);
 576                netif_rx(skb);
 577                rcu_read_unlock();
 578                return 0;
 579        }
 580
 581        icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 582        rcu_read_unlock();
 583out:
 584        kfree_skb(skb);
 585        return 0;
 586}
 587
 588/*
 589 * Returns the embedded IPv4 address if the IPv6 address
 590 * comes from 6rd / 6to4 (RFC 3056) addr space.
 591 */
 592static inline
 593__be32 try_6rd(struct in6_addr *v6dst, struct ip_tunnel *tunnel)
 594{
 595        __be32 dst = 0;
 596
 597#ifdef CONFIG_IPV6_SIT_6RD
 598        if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 599                              tunnel->ip6rd.prefixlen)) {
 600                unsigned pbw0, pbi0;
 601                int pbi1;
 602                u32 d;
 603
 604                pbw0 = tunnel->ip6rd.prefixlen >> 5;
 605                pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 606
 607                d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 608                    tunnel->ip6rd.relay_prefixlen;
 609
 610                pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 611                if (pbi1 > 0)
 612                        d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 613                             (32 - pbi1);
 614
 615                dst = tunnel->ip6rd.relay_prefix | htonl(d);
 616        }
 617#else
 618        if (v6dst->s6_addr16[0] == htons(0x2002)) {
 619                /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 620                memcpy(&dst, &v6dst->s6_addr16[1], 4);
 621        }
 622#endif
 623        return dst;
 624}
 625
 626/*
 627 *      This function assumes it is being called from dev_queue_xmit()
 628 *      and that skb is filled properly by that function.
 629 */
 630
 631static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 632                                     struct net_device *dev)
 633{
 634        struct ip_tunnel *tunnel = netdev_priv(dev);
 635        struct net_device_stats *stats = &dev->stats;
 636        struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
 637        struct iphdr  *tiph = &tunnel->parms.iph;
 638        struct ipv6hdr *iph6 = ipv6_hdr(skb);
 639        u8     tos = tunnel->parms.iph.tos;
 640        __be16 df = tiph->frag_off;
 641        struct rtable *rt;                      /* Route to the other host */
 642        struct net_device *tdev;                        /* Device to other host */
 643        struct iphdr  *iph;                     /* Our new IP header */
 644        unsigned int max_headroom;              /* The extra header space needed */
 645        __be32 dst = tiph->daddr;
 646        int    mtu;
 647        struct in6_addr *addr6;
 648        int addr_type;
 649
 650        if (skb->protocol != htons(ETH_P_IPV6))
 651                goto tx_error;
 652
 653        /* ISATAP (RFC4214) - must come before 6to4 */
 654        if (dev->priv_flags & IFF_ISATAP) {
 655                struct neighbour *neigh = NULL;
 656
 657                if (skb_dst(skb))
 658                        neigh = skb_dst(skb)->neighbour;
 659
 660                if (neigh == NULL) {
 661                        if (net_ratelimit())
 662                                printk(KERN_DEBUG "sit: nexthop == NULL\n");
 663                        goto tx_error;
 664                }
 665
 666                addr6 = (struct in6_addr*)&neigh->primary_key;
 667                addr_type = ipv6_addr_type(addr6);
 668
 669                if ((addr_type & IPV6_ADDR_UNICAST) &&
 670                     ipv6_addr_is_isatap(addr6))
 671                        dst = addr6->s6_addr32[3];
 672                else
 673                        goto tx_error;
 674        }
 675
 676        if (!dst)
 677                dst = try_6rd(&iph6->daddr, tunnel);
 678
 679        if (!dst) {
 680                struct neighbour *neigh = NULL;
 681
 682                if (skb_dst(skb))
 683                        neigh = skb_dst(skb)->neighbour;
 684
 685                if (neigh == NULL) {
 686                        if (net_ratelimit())
 687                                printk(KERN_DEBUG "sit: nexthop == NULL\n");
 688                        goto tx_error;
 689                }
 690
 691                addr6 = (struct in6_addr*)&neigh->primary_key;
 692                addr_type = ipv6_addr_type(addr6);
 693
 694                if (addr_type == IPV6_ADDR_ANY) {
 695                        addr6 = &ipv6_hdr(skb)->daddr;
 696                        addr_type = ipv6_addr_type(addr6);
 697                }
 698
 699                if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 700                        goto tx_error_icmp;
 701
 702                dst = addr6->s6_addr32[3];
 703        }
 704
 705        {
 706                struct flowi fl = { .nl_u = { .ip4_u =
 707                                              { .daddr = dst,
 708                                                .saddr = tiph->saddr,
 709                                                .tos = RT_TOS(tos) } },
 710                                    .oif = tunnel->parms.link,
 711                                    .proto = IPPROTO_IPV6 };
 712                if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 713                        stats->tx_carrier_errors++;
 714                        goto tx_error_icmp;
 715                }
 716        }
 717        if (rt->rt_type != RTN_UNICAST) {
 718                ip_rt_put(rt);
 719                stats->tx_carrier_errors++;
 720                goto tx_error_icmp;
 721        }
 722        tdev = rt->u.dst.dev;
 723
 724        if (tdev == dev) {
 725                ip_rt_put(rt);
 726                stats->collisions++;
 727                goto tx_error;
 728        }
 729
 730        if (df) {
 731                mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 732
 733                if (mtu < 68) {
 734                        stats->collisions++;
 735                        ip_rt_put(rt);
 736                        goto tx_error;
 737                }
 738
 739                if (mtu < IPV6_MIN_MTU) {
 740                        mtu = IPV6_MIN_MTU;
 741                        df = 0;
 742                }
 743
 744                if (tunnel->parms.iph.daddr && skb_dst(skb))
 745                        skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 746
 747                if (skb->len > mtu) {
 748                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
 749                        ip_rt_put(rt);
 750                        goto tx_error;
 751                }
 752        }
 753
 754        if (tunnel->err_count > 0) {
 755                if (time_before(jiffies,
 756                                tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 757                        tunnel->err_count--;
 758                        dst_link_failure(skb);
 759                } else
 760                        tunnel->err_count = 0;
 761        }
 762
 763        /*
 764         * Okay, now see if we can stuff it in the buffer as-is.
 765         */
 766        max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 767
 768        if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 769            (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 770                struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 771                if (!new_skb) {
 772                        ip_rt_put(rt);
 773                        txq->tx_dropped++;
 774                        dev_kfree_skb(skb);
 775                        return NETDEV_TX_OK;
 776                }
 777                if (skb->sk)
 778                        skb_set_owner_w(new_skb, skb->sk);
 779                dev_kfree_skb(skb);
 780                skb = new_skb;
 781                iph6 = ipv6_hdr(skb);
 782        }
 783
 784        skb->transport_header = skb->network_header;
 785        skb_push(skb, sizeof(struct iphdr));
 786        skb_reset_network_header(skb);
 787        memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 788        IPCB(skb)->flags = 0;
 789        skb_dst_drop(skb);
 790        skb_dst_set(skb, &rt->u.dst);
 791
 792        /*
 793         *      Push down and install the IPIP header.
 794         */
 795
 796        iph                     =       ip_hdr(skb);
 797        iph->version            =       4;
 798        iph->ihl                =       sizeof(struct iphdr)>>2;
 799        iph->frag_off           =       df;
 800        iph->protocol           =       IPPROTO_IPV6;
 801        iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 802        iph->daddr              =       rt->rt_dst;
 803        iph->saddr              =       rt->rt_src;
 804
 805        if ((iph->ttl = tiph->ttl) == 0)
 806                iph->ttl        =       iph6->hop_limit;
 807
 808        nf_reset(skb);
 809
 810        IPTUNNEL_XMIT();
 811        return NETDEV_TX_OK;
 812
 813tx_error_icmp:
 814        dst_link_failure(skb);
 815tx_error:
 816        stats->tx_errors++;
 817        dev_kfree_skb(skb);
 818        return NETDEV_TX_OK;
 819}
 820
 821static void ipip6_tunnel_bind_dev(struct net_device *dev)
 822{
 823        struct net_device *tdev = NULL;
 824        struct ip_tunnel *tunnel;
 825        struct iphdr *iph;
 826
 827        tunnel = netdev_priv(dev);
 828        iph = &tunnel->parms.iph;
 829
 830        if (iph->daddr) {
 831                struct flowi fl = { .nl_u = { .ip4_u =
 832                                              { .daddr = iph->daddr,
 833                                                .saddr = iph->saddr,
 834                                                .tos = RT_TOS(iph->tos) } },
 835                                    .oif = tunnel->parms.link,
 836                                    .proto = IPPROTO_IPV6 };
 837                struct rtable *rt;
 838                if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 839                        tdev = rt->u.dst.dev;
 840                        ip_rt_put(rt);
 841                }
 842                dev->flags |= IFF_POINTOPOINT;
 843        }
 844
 845        if (!tdev && tunnel->parms.link)
 846                tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 847
 848        if (tdev) {
 849                dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 850                dev->mtu = tdev->mtu - sizeof(struct iphdr);
 851                if (dev->mtu < IPV6_MIN_MTU)
 852                        dev->mtu = IPV6_MIN_MTU;
 853        }
 854        dev->iflink = tunnel->parms.link;
 855}
 856
 857static int
 858ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 859{
 860        int err = 0;
 861        struct ip_tunnel_parm p;
 862        struct ip_tunnel_prl prl;
 863        struct ip_tunnel *t;
 864        struct net *net = dev_net(dev);
 865        struct sit_net *sitn = net_generic(net, sit_net_id);
 866#ifdef CONFIG_IPV6_SIT_6RD
 867        struct ip_tunnel_6rd ip6rd;
 868#endif
 869
 870        switch (cmd) {
 871        case SIOCGETTUNNEL:
 872#ifdef CONFIG_IPV6_SIT_6RD
 873        case SIOCGET6RD:
 874#endif
 875                t = NULL;
 876                if (dev == sitn->fb_tunnel_dev) {
 877                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 878                                err = -EFAULT;
 879                                break;
 880                        }
 881                        t = ipip6_tunnel_locate(net, &p, 0);
 882                }
 883                if (t == NULL)
 884                        t = netdev_priv(dev);
 885
 886                err = -EFAULT;
 887                if (cmd == SIOCGETTUNNEL) {
 888                        memcpy(&p, &t->parms, sizeof(p));
 889                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
 890                                         sizeof(p)))
 891                                goto done;
 892#ifdef CONFIG_IPV6_SIT_6RD
 893                } else {
 894                        ipv6_addr_copy(&ip6rd.prefix, &t->ip6rd.prefix);
 895                        ip6rd.relay_prefix = t->ip6rd.relay_prefix;
 896                        ip6rd.prefixlen = t->ip6rd.prefixlen;
 897                        ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
 898                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
 899                                         sizeof(ip6rd)))
 900                                goto done;
 901#endif
 902                }
 903                err = 0;
 904                break;
 905
 906        case SIOCADDTUNNEL:
 907        case SIOCCHGTUNNEL:
 908                err = -EPERM;
 909                if (!capable(CAP_NET_ADMIN))
 910                        goto done;
 911
 912                err = -EFAULT;
 913                if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 914                        goto done;
 915
 916                err = -EINVAL;
 917                if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
 918                    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 919                        goto done;
 920                if (p.iph.ttl)
 921                        p.iph.frag_off |= htons(IP_DF);
 922
 923                t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 924
 925                if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 926                        if (t != NULL) {
 927                                if (t->dev != dev) {
 928                                        err = -EEXIST;
 929                                        break;
 930                                }
 931                        } else {
 932                                if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 933                                    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 934                                        err = -EINVAL;
 935                                        break;
 936                                }
 937                                t = netdev_priv(dev);
 938                                ipip6_tunnel_unlink(sitn, t);
 939                                t->parms.iph.saddr = p.iph.saddr;
 940                                t->parms.iph.daddr = p.iph.daddr;
 941                                memcpy(dev->dev_addr, &p.iph.saddr, 4);
 942                                memcpy(dev->broadcast, &p.iph.daddr, 4);
 943                                ipip6_tunnel_link(sitn, t);
 944                                netdev_state_change(dev);
 945                        }
 946                }
 947
 948                if (t) {
 949                        err = 0;
 950                        if (cmd == SIOCCHGTUNNEL) {
 951                                t->parms.iph.ttl = p.iph.ttl;
 952                                t->parms.iph.tos = p.iph.tos;
 953                                if (t->parms.link != p.link) {
 954                                        t->parms.link = p.link;
 955                                        ipip6_tunnel_bind_dev(dev);
 956                                        netdev_state_change(dev);
 957                                }
 958                        }
 959                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 960                                err = -EFAULT;
 961                } else
 962                        err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 963                break;
 964
 965        case SIOCDELTUNNEL:
 966                err = -EPERM;
 967                if (!capable(CAP_NET_ADMIN))
 968                        goto done;
 969
 970                if (dev == sitn->fb_tunnel_dev) {
 971                        err = -EFAULT;
 972                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 973                                goto done;
 974                        err = -ENOENT;
 975                        if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
 976                                goto done;
 977                        err = -EPERM;
 978                        if (t == netdev_priv(sitn->fb_tunnel_dev))
 979                                goto done;
 980                        dev = t->dev;
 981                }
 982                unregister_netdevice(dev);
 983                err = 0;
 984                break;
 985
 986        case SIOCGETPRL:
 987                err = -EINVAL;
 988                if (dev == sitn->fb_tunnel_dev)
 989                        goto done;
 990                err = -ENOENT;
 991                if (!(t = netdev_priv(dev)))
 992                        goto done;
 993                err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
 994                break;
 995
 996        case SIOCADDPRL:
 997        case SIOCDELPRL:
 998        case SIOCCHGPRL:
 999                err = -EPERM;
1000                if (!capable(CAP_NET_ADMIN))
1001                        goto done;
1002                err = -EINVAL;
1003                if (dev == sitn->fb_tunnel_dev)
1004                        goto done;
1005                err = -EFAULT;
1006                if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1007                        goto done;
1008                err = -ENOENT;
1009                if (!(t = netdev_priv(dev)))
1010                        goto done;
1011
1012                switch (cmd) {
1013                case SIOCDELPRL:
1014                        err = ipip6_tunnel_del_prl(t, &prl);
1015                        break;
1016                case SIOCADDPRL:
1017                case SIOCCHGPRL:
1018                        err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1019                        break;
1020                }
1021                netdev_state_change(dev);
1022                break;
1023
1024#ifdef CONFIG_IPV6_SIT_6RD
1025        case SIOCADD6RD:
1026        case SIOCCHG6RD:
1027        case SIOCDEL6RD:
1028                err = -EPERM;
1029                if (!capable(CAP_NET_ADMIN))
1030                        goto done;
1031
1032                err = -EFAULT;
1033                if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1034                                   sizeof(ip6rd)))
1035                        goto done;
1036
1037                t = netdev_priv(dev);
1038
1039                if (cmd != SIOCDEL6RD) {
1040                        struct in6_addr prefix;
1041                        __be32 relay_prefix;
1042
1043                        err = -EINVAL;
1044                        if (ip6rd.relay_prefixlen > 32 ||
1045                            ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1046                                goto done;
1047
1048                        ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1049                                         ip6rd.prefixlen);
1050                        if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1051                                goto done;
1052                        if (ip6rd.relay_prefixlen)
1053                                relay_prefix = ip6rd.relay_prefix &
1054                                               htonl(0xffffffffUL <<
1055                                                     (32 - ip6rd.relay_prefixlen));
1056                        else
1057                                relay_prefix = 0;
1058                        if (relay_prefix != ip6rd.relay_prefix)
1059                                goto done;
1060
1061                        ipv6_addr_copy(&t->ip6rd.prefix, &prefix);
1062                        t->ip6rd.relay_prefix = relay_prefix;
1063                        t->ip6rd.prefixlen = ip6rd.prefixlen;
1064                        t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1065                } else
1066                        ipip6_tunnel_clone_6rd(dev, sitn);
1067
1068                err = 0;
1069                break;
1070#endif
1071
1072        default:
1073                err = -EINVAL;
1074        }
1075
1076done:
1077        return err;
1078}
1079
1080static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1081{
1082        if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1083                return -EINVAL;
1084        dev->mtu = new_mtu;
1085        return 0;
1086}
1087
1088static const struct net_device_ops ipip6_netdev_ops = {
1089        .ndo_uninit     = ipip6_tunnel_uninit,
1090        .ndo_start_xmit = ipip6_tunnel_xmit,
1091        .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1092        .ndo_change_mtu = ipip6_tunnel_change_mtu,
1093};
1094
1095static void ipip6_tunnel_setup(struct net_device *dev)
1096{
1097        dev->netdev_ops         = &ipip6_netdev_ops;
1098        dev->destructor         = free_netdev;
1099
1100        dev->type               = ARPHRD_SIT;
1101        dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1102        dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1103        dev->flags              = IFF_NOARP;
1104        dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1105        dev->iflink             = 0;
1106        dev->addr_len           = 4;
1107        dev->features           |= NETIF_F_NETNS_LOCAL;
1108}
1109
1110static void ipip6_tunnel_init(struct net_device *dev)
1111{
1112        struct ip_tunnel *tunnel = netdev_priv(dev);
1113
1114        tunnel->dev = dev;
1115        strcpy(tunnel->parms.name, dev->name);
1116
1117        memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1118        memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1119
1120        ipip6_tunnel_bind_dev(dev);
1121}
1122
1123static void ipip6_fb_tunnel_init(struct net_device *dev)
1124{
1125        struct ip_tunnel *tunnel = netdev_priv(dev);
1126        struct iphdr *iph = &tunnel->parms.iph;
1127        struct net *net = dev_net(dev);
1128        struct sit_net *sitn = net_generic(net, sit_net_id);
1129
1130        tunnel->dev = dev;
1131        strcpy(tunnel->parms.name, dev->name);
1132
1133        iph->version            = 4;
1134        iph->protocol           = IPPROTO_IPV6;
1135        iph->ihl                = 5;
1136        iph->ttl                = 64;
1137
1138        dev_hold(dev);
1139        sitn->tunnels_wc[0]     = tunnel;
1140}
1141
1142static struct xfrm_tunnel sit_handler = {
1143        .handler        =       ipip6_rcv,
1144        .err_handler    =       ipip6_err,
1145        .priority       =       1,
1146};
1147
1148static void sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1149{
1150        int prio;
1151
1152        for (prio = 1; prio < 4; prio++) {
1153                int h;
1154                for (h = 0; h < HASH_SIZE; h++) {
1155                        struct ip_tunnel *t = sitn->tunnels[prio][h];
1156
1157                        while (t != NULL) {
1158                                unregister_netdevice_queue(t->dev, head);
1159                                t = t->next;
1160                        }
1161                }
1162        }
1163}
1164
1165static int sit_init_net(struct net *net)
1166{
1167        struct sit_net *sitn = net_generic(net, sit_net_id);
1168        int err;
1169
1170        sitn->tunnels[0] = sitn->tunnels_wc;
1171        sitn->tunnels[1] = sitn->tunnels_l;
1172        sitn->tunnels[2] = sitn->tunnels_r;
1173        sitn->tunnels[3] = sitn->tunnels_r_l;
1174
1175        sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1176                                           ipip6_tunnel_setup);
1177        if (!sitn->fb_tunnel_dev) {
1178                err = -ENOMEM;
1179                goto err_alloc_dev;
1180        }
1181        dev_net_set(sitn->fb_tunnel_dev, net);
1182
1183        ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1184        ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1185
1186        if ((err = register_netdev(sitn->fb_tunnel_dev)))
1187                goto err_reg_dev;
1188
1189        return 0;
1190
1191err_reg_dev:
1192        dev_put(sitn->fb_tunnel_dev);
1193        free_netdev(sitn->fb_tunnel_dev);
1194err_alloc_dev:
1195        return err;
1196}
1197
1198static void sit_exit_net(struct net *net)
1199{
1200        struct sit_net *sitn = net_generic(net, sit_net_id);
1201        LIST_HEAD(list);
1202
1203        rtnl_lock();
1204        sit_destroy_tunnels(sitn, &list);
1205        unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1206        unregister_netdevice_many(&list);
1207        rtnl_unlock();
1208}
1209
1210static struct pernet_operations sit_net_ops = {
1211        .init = sit_init_net,
1212        .exit = sit_exit_net,
1213        .id   = &sit_net_id,
1214        .size = sizeof(struct sit_net),
1215};
1216
1217static void __exit sit_cleanup(void)
1218{
1219        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1220
1221        unregister_pernet_device(&sit_net_ops);
1222        rcu_barrier(); /* Wait for completion of call_rcu()'s */
1223}
1224
1225static int __init sit_init(void)
1226{
1227        int err;
1228
1229        printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1230
1231        if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1232                printk(KERN_INFO "sit init: Can't add protocol\n");
1233                return -EAGAIN;
1234        }
1235
1236        err = register_pernet_device(&sit_net_ops);
1237        if (err < 0)
1238                xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1239
1240        return err;
1241}
1242
1243module_init(sit_init);
1244module_exit(sit_cleanup);
1245MODULE_LICENSE("GPL");
1246MODULE_ALIAS("sit0");
1247