linux/net/ipv6/sit.c
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   1/*
   2 *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
   3 *      Linux INET6 implementation
   4 *
   5 *      Authors:
   6 *      Pedro Roque             <roque@di.fc.ul.pt>
   7 *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
   8 *
   9 *      This program is free software; you can redistribute it and/or
  10 *      modify it under the terms of the GNU General Public License
  11 *      as published by the Free Software Foundation; either version
  12 *      2 of the License, or (at your option) any later version.
  13 *
  14 *      Changes:
  15 * Roger Venning <r.venning@telstra.com>:       6to4 support
  16 * Nate Thompson <nate@thebog.net>:             6to4 support
  17 * Fred Templin <fred.l.templin@boeing.com>:    isatap support
  18 */
  19
  20#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  21
  22#include <linux/module.h>
  23#include <linux/capability.h>
  24#include <linux/errno.h>
  25#include <linux/types.h>
  26#include <linux/socket.h>
  27#include <linux/sockios.h>
  28#include <linux/net.h>
  29#include <linux/in6.h>
  30#include <linux/netdevice.h>
  31#include <linux/if_arp.h>
  32#include <linux/icmp.h>
  33#include <linux/slab.h>
  34#include <asm/uaccess.h>
  35#include <linux/init.h>
  36#include <linux/netfilter_ipv4.h>
  37#include <linux/if_ether.h>
  38
  39#include <net/sock.h>
  40#include <net/snmp.h>
  41
  42#include <net/ipv6.h>
  43#include <net/protocol.h>
  44#include <net/transp_v6.h>
  45#include <net/ip6_fib.h>
  46#include <net/ip6_route.h>
  47#include <net/ndisc.h>
  48#include <net/addrconf.h>
  49#include <net/ip.h>
  50#include <net/udp.h>
  51#include <net/icmp.h>
  52#include <net/ip_tunnels.h>
  53#include <net/inet_ecn.h>
  54#include <net/xfrm.h>
  55#include <net/dsfield.h>
  56#include <net/net_namespace.h>
  57#include <net/netns/generic.h>
  58
  59/*
  60   This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
  61
  62   For comments look at net/ipv4/ip_gre.c --ANK
  63 */
  64
  65#define HASH_SIZE  16
  66#define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
  67
  68static bool log_ecn_error = true;
  69module_param(log_ecn_error, bool, 0644);
  70MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
  71
  72static int ipip6_tunnel_init(struct net_device *dev);
  73static void ipip6_tunnel_setup(struct net_device *dev);
  74static void ipip6_dev_free(struct net_device *dev);
  75static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
  76                      __be32 *v4dst);
  77static struct rtnl_link_ops sit_link_ops __read_mostly;
  78
  79static int sit_net_id __read_mostly;
  80struct sit_net {
  81        struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
  82        struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
  83        struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
  84        struct ip_tunnel __rcu *tunnels_wc[1];
  85        struct ip_tunnel __rcu **tunnels[4];
  86
  87        struct net_device *fb_tunnel_dev;
  88};
  89
  90/*
  91 * Must be invoked with rcu_read_lock
  92 */
  93static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
  94                struct net_device *dev, __be32 remote, __be32 local)
  95{
  96        unsigned int h0 = HASH(remote);
  97        unsigned int h1 = HASH(local);
  98        struct ip_tunnel *t;
  99        struct sit_net *sitn = net_generic(net, sit_net_id);
 100
 101        for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
 102                if (local == t->parms.iph.saddr &&
 103                    remote == t->parms.iph.daddr &&
 104                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 105                    (t->dev->flags & IFF_UP))
 106                        return t;
 107        }
 108        for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
 109                if (remote == t->parms.iph.daddr &&
 110                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 111                    (t->dev->flags & IFF_UP))
 112                        return t;
 113        }
 114        for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
 115                if (local == t->parms.iph.saddr &&
 116                    (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
 117                    (t->dev->flags & IFF_UP))
 118                        return t;
 119        }
 120        t = rcu_dereference(sitn->tunnels_wc[0]);
 121        if ((t != NULL) && (t->dev->flags & IFF_UP))
 122                return t;
 123        return NULL;
 124}
 125
 126static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
 127                struct ip_tunnel_parm *parms)
 128{
 129        __be32 remote = parms->iph.daddr;
 130        __be32 local = parms->iph.saddr;
 131        unsigned int h = 0;
 132        int prio = 0;
 133
 134        if (remote) {
 135                prio |= 2;
 136                h ^= HASH(remote);
 137        }
 138        if (local) {
 139                prio |= 1;
 140                h ^= HASH(local);
 141        }
 142        return &sitn->tunnels[prio][h];
 143}
 144
 145static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
 146                struct ip_tunnel *t)
 147{
 148        return __ipip6_bucket(sitn, &t->parms);
 149}
 150
 151static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
 152{
 153        struct ip_tunnel __rcu **tp;
 154        struct ip_tunnel *iter;
 155
 156        for (tp = ipip6_bucket(sitn, t);
 157             (iter = rtnl_dereference(*tp)) != NULL;
 158             tp = &iter->next) {
 159                if (t == iter) {
 160                        rcu_assign_pointer(*tp, t->next);
 161                        break;
 162                }
 163        }
 164}
 165
 166static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
 167{
 168        struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
 169
 170        rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 171        rcu_assign_pointer(*tp, t);
 172}
 173
 174static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
 175{
 176#ifdef CONFIG_IPV6_SIT_6RD
 177        struct ip_tunnel *t = netdev_priv(dev);
 178
 179        if (t->dev == sitn->fb_tunnel_dev) {
 180                ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
 181                t->ip6rd.relay_prefix = 0;
 182                t->ip6rd.prefixlen = 16;
 183                t->ip6rd.relay_prefixlen = 0;
 184        } else {
 185                struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
 186                memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
 187        }
 188#endif
 189}
 190
 191static int ipip6_tunnel_create(struct net_device *dev)
 192{
 193        struct ip_tunnel *t = netdev_priv(dev);
 194        struct net *net = dev_net(dev);
 195        struct sit_net *sitn = net_generic(net, sit_net_id);
 196        int err;
 197
 198        err = ipip6_tunnel_init(dev);
 199        if (err < 0)
 200                goto out;
 201        ipip6_tunnel_clone_6rd(dev, sitn);
 202
 203        if ((__force u16)t->parms.i_flags & SIT_ISATAP)
 204                dev->priv_flags |= IFF_ISATAP;
 205
 206        err = register_netdevice(dev);
 207        if (err < 0)
 208                goto out;
 209
 210        strcpy(t->parms.name, dev->name);
 211        dev->rtnl_link_ops = &sit_link_ops;
 212
 213        dev_hold(dev);
 214
 215        ipip6_tunnel_link(sitn, t);
 216        return 0;
 217
 218out:
 219        return err;
 220}
 221
 222static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
 223                struct ip_tunnel_parm *parms, int create)
 224{
 225        __be32 remote = parms->iph.daddr;
 226        __be32 local = parms->iph.saddr;
 227        struct ip_tunnel *t, *nt;
 228        struct ip_tunnel __rcu **tp;
 229        struct net_device *dev;
 230        char name[IFNAMSIZ];
 231        struct sit_net *sitn = net_generic(net, sit_net_id);
 232
 233        for (tp = __ipip6_bucket(sitn, parms);
 234            (t = rtnl_dereference(*tp)) != NULL;
 235             tp = &t->next) {
 236                if (local == t->parms.iph.saddr &&
 237                    remote == t->parms.iph.daddr &&
 238                    parms->link == t->parms.link) {
 239                        if (create)
 240                                return NULL;
 241                        else
 242                                return t;
 243                }
 244        }
 245        if (!create)
 246                goto failed;
 247
 248        if (parms->name[0])
 249                strlcpy(name, parms->name, IFNAMSIZ);
 250        else
 251                strcpy(name, "sit%d");
 252
 253        dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
 254        if (dev == NULL)
 255                return NULL;
 256
 257        dev_net_set(dev, net);
 258
 259        nt = netdev_priv(dev);
 260
 261        nt->parms = *parms;
 262        if (ipip6_tunnel_create(dev) < 0)
 263                goto failed_free;
 264
 265        return nt;
 266
 267failed_free:
 268        ipip6_dev_free(dev);
 269failed:
 270        return NULL;
 271}
 272
 273#define for_each_prl_rcu(start)                 \
 274        for (prl = rcu_dereference(start);      \
 275             prl;                               \
 276             prl = rcu_dereference(prl->next))
 277
 278static struct ip_tunnel_prl_entry *
 279__ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
 280{
 281        struct ip_tunnel_prl_entry *prl;
 282
 283        for_each_prl_rcu(t->prl)
 284                if (prl->addr == addr)
 285                        break;
 286        return prl;
 287
 288}
 289
 290static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
 291                                struct ip_tunnel_prl __user *a)
 292{
 293        struct ip_tunnel_prl kprl, *kp;
 294        struct ip_tunnel_prl_entry *prl;
 295        unsigned int cmax, c = 0, ca, len;
 296        int ret = 0;
 297
 298        if (copy_from_user(&kprl, a, sizeof(kprl)))
 299                return -EFAULT;
 300        cmax = kprl.datalen / sizeof(kprl);
 301        if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
 302                cmax = 1;
 303
 304        /* For simple GET or for root users,
 305         * we try harder to allocate.
 306         */
 307        kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
 308                kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
 309                NULL;
 310
 311        rcu_read_lock();
 312
 313        ca = t->prl_count < cmax ? t->prl_count : cmax;
 314
 315        if (!kp) {
 316                /* We don't try hard to allocate much memory for
 317                 * non-root users.
 318                 * For root users, retry allocating enough memory for
 319                 * the answer.
 320                 */
 321                kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
 322                if (!kp) {
 323                        ret = -ENOMEM;
 324                        goto out;
 325                }
 326        }
 327
 328        c = 0;
 329        for_each_prl_rcu(t->prl) {
 330                if (c >= cmax)
 331                        break;
 332                if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
 333                        continue;
 334                kp[c].addr = prl->addr;
 335                kp[c].flags = prl->flags;
 336                c++;
 337                if (kprl.addr != htonl(INADDR_ANY))
 338                        break;
 339        }
 340out:
 341        rcu_read_unlock();
 342
 343        len = sizeof(*kp) * c;
 344        ret = 0;
 345        if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
 346                ret = -EFAULT;
 347
 348        kfree(kp);
 349
 350        return ret;
 351}
 352
 353static int
 354ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
 355{
 356        struct ip_tunnel_prl_entry *p;
 357        int err = 0;
 358
 359        if (a->addr == htonl(INADDR_ANY))
 360                return -EINVAL;
 361
 362        ASSERT_RTNL();
 363
 364        for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
 365                if (p->addr == a->addr) {
 366                        if (chg) {
 367                                p->flags = a->flags;
 368                                goto out;
 369                        }
 370                        err = -EEXIST;
 371                        goto out;
 372                }
 373        }
 374
 375        if (chg) {
 376                err = -ENXIO;
 377                goto out;
 378        }
 379
 380        p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
 381        if (!p) {
 382                err = -ENOBUFS;
 383                goto out;
 384        }
 385
 386        p->next = t->prl;
 387        p->addr = a->addr;
 388        p->flags = a->flags;
 389        t->prl_count++;
 390        rcu_assign_pointer(t->prl, p);
 391out:
 392        return err;
 393}
 394
 395static void prl_list_destroy_rcu(struct rcu_head *head)
 396{
 397        struct ip_tunnel_prl_entry *p, *n;
 398
 399        p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
 400        do {
 401                n = rcu_dereference_protected(p->next, 1);
 402                kfree(p);
 403                p = n;
 404        } while (p);
 405}
 406
 407static int
 408ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
 409{
 410        struct ip_tunnel_prl_entry *x;
 411        struct ip_tunnel_prl_entry __rcu **p;
 412        int err = 0;
 413
 414        ASSERT_RTNL();
 415
 416        if (a && a->addr != htonl(INADDR_ANY)) {
 417                for (p = &t->prl;
 418                     (x = rtnl_dereference(*p)) != NULL;
 419                     p = &x->next) {
 420                        if (x->addr == a->addr) {
 421                                *p = x->next;
 422                                kfree_rcu(x, rcu_head);
 423                                t->prl_count--;
 424                                goto out;
 425                        }
 426                }
 427                err = -ENXIO;
 428        } else {
 429                x = rtnl_dereference(t->prl);
 430                if (x) {
 431                        t->prl_count = 0;
 432                        call_rcu(&x->rcu_head, prl_list_destroy_rcu);
 433                        t->prl = NULL;
 434                }
 435        }
 436out:
 437        return err;
 438}
 439
 440static int
 441isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
 442{
 443        struct ip_tunnel_prl_entry *p;
 444        int ok = 1;
 445
 446        rcu_read_lock();
 447        p = __ipip6_tunnel_locate_prl(t, iph->saddr);
 448        if (p) {
 449                if (p->flags & PRL_DEFAULT)
 450                        skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
 451                else
 452                        skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
 453        } else {
 454                const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
 455
 456                if (ipv6_addr_is_isatap(addr6) &&
 457                    (addr6->s6_addr32[3] == iph->saddr) &&
 458                    ipv6_chk_prefix(addr6, t->dev))
 459                        skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
 460                else
 461                        ok = 0;
 462        }
 463        rcu_read_unlock();
 464        return ok;
 465}
 466
 467static void ipip6_tunnel_uninit(struct net_device *dev)
 468{
 469        struct ip_tunnel *tunnel = netdev_priv(dev);
 470        struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
 471
 472        if (dev == sitn->fb_tunnel_dev) {
 473                RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
 474        } else {
 475                ipip6_tunnel_unlink(sitn, tunnel);
 476                ipip6_tunnel_del_prl(tunnel, NULL);
 477        }
 478        dev_put(dev);
 479}
 480
 481
 482static int ipip6_err(struct sk_buff *skb, u32 info)
 483{
 484
 485/* All the routers (except for Linux) return only
 486   8 bytes of packet payload. It means, that precise relaying of
 487   ICMP in the real Internet is absolutely infeasible.
 488 */
 489        const struct iphdr *iph = (const struct iphdr *)skb->data;
 490        const int type = icmp_hdr(skb)->type;
 491        const int code = icmp_hdr(skb)->code;
 492        struct ip_tunnel *t;
 493        int err;
 494
 495        switch (type) {
 496        default:
 497        case ICMP_PARAMETERPROB:
 498                return 0;
 499
 500        case ICMP_DEST_UNREACH:
 501                switch (code) {
 502                case ICMP_SR_FAILED:
 503                case ICMP_PORT_UNREACH:
 504                        /* Impossible event. */
 505                        return 0;
 506                default:
 507                        /* All others are translated to HOST_UNREACH.
 508                           rfc2003 contains "deep thoughts" about NET_UNREACH,
 509                           I believe they are just ether pollution. --ANK
 510                         */
 511                        break;
 512                }
 513                break;
 514        case ICMP_TIME_EXCEEDED:
 515                if (code != ICMP_EXC_TTL)
 516                        return 0;
 517                break;
 518        case ICMP_REDIRECT:
 519                break;
 520        }
 521
 522        err = -ENOENT;
 523
 524        t = ipip6_tunnel_lookup(dev_net(skb->dev),
 525                                skb->dev,
 526                                iph->daddr,
 527                                iph->saddr);
 528        if (t == NULL)
 529                goto out;
 530
 531        if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 532                ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 533                                 t->dev->ifindex, 0, IPPROTO_IPV6, 0);
 534                err = 0;
 535                goto out;
 536        }
 537        if (type == ICMP_REDIRECT) {
 538                ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
 539                              IPPROTO_IPV6, 0);
 540                err = 0;
 541                goto out;
 542        }
 543
 544        if (t->parms.iph.daddr == 0)
 545                goto out;
 546
 547        err = 0;
 548        if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 549                goto out;
 550
 551        if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 552                t->err_count++;
 553        else
 554                t->err_count = 1;
 555        t->err_time = jiffies;
 556out:
 557        return err;
 558}
 559
 560static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
 561                                  const struct in6_addr *v6addr)
 562{
 563        __be32 v4embed = 0;
 564        if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
 565                return true;
 566        return false;
 567}
 568
 569static int ipip6_rcv(struct sk_buff *skb)
 570{
 571        const struct iphdr *iph = ip_hdr(skb);
 572        struct ip_tunnel *tunnel;
 573        int err;
 574
 575        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 576                                     iph->saddr, iph->daddr);
 577        if (tunnel != NULL) {
 578                struct pcpu_tstats *tstats;
 579
 580                if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
 581                    tunnel->parms.iph.protocol != 0)
 582                        goto out;
 583
 584                secpath_reset(skb);
 585                skb->mac_header = skb->network_header;
 586                skb_reset_network_header(skb);
 587                IPCB(skb)->flags = 0;
 588                skb->protocol = htons(ETH_P_IPV6);
 589                skb->pkt_type = PACKET_HOST;
 590
 591                if (tunnel->dev->priv_flags & IFF_ISATAP) {
 592                        if (!isatap_chksrc(skb, iph, tunnel)) {
 593                                tunnel->dev->stats.rx_errors++;
 594                                goto out;
 595                        }
 596                } else if (!(tunnel->dev->flags&IFF_POINTOPOINT)) {
 597                        if (is_spoofed_6rd(tunnel, iph->saddr,
 598                                           &ipv6_hdr(skb)->saddr) ||
 599                            is_spoofed_6rd(tunnel, iph->daddr,
 600                                           &ipv6_hdr(skb)->daddr)) {
 601                                tunnel->dev->stats.rx_errors++;
 602                                goto out;
 603                        }
 604                }
 605
 606                __skb_tunnel_rx(skb, tunnel->dev);
 607
 608                err = IP_ECN_decapsulate(iph, skb);
 609                if (unlikely(err)) {
 610                        if (log_ecn_error)
 611                                net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 612                                                     &iph->saddr, iph->tos);
 613                        if (err > 1) {
 614                                ++tunnel->dev->stats.rx_frame_errors;
 615                                ++tunnel->dev->stats.rx_errors;
 616                                goto out;
 617                        }
 618                }
 619
 620                tstats = this_cpu_ptr(tunnel->dev->tstats);
 621                tstats->rx_packets++;
 622                tstats->rx_bytes += skb->len;
 623
 624                if (tunnel->net != dev_net(tunnel->dev))
 625                        skb_scrub_packet(skb);
 626                netif_rx(skb);
 627
 628                return 0;
 629        }
 630
 631        /* no tunnel matched,  let upstream know, ipsec may handle it */
 632        return 1;
 633out:
 634        kfree_skb(skb);
 635        return 0;
 636}
 637
 638static const struct tnl_ptk_info tpi = {
 639        /* no tunnel info required for ipip. */
 640        .proto = htons(ETH_P_IP),
 641};
 642
 643static int ipip_rcv(struct sk_buff *skb)
 644{
 645        const struct iphdr *iph;
 646        struct ip_tunnel *tunnel;
 647
 648        iph = ip_hdr(skb);
 649        tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
 650                                     iph->saddr, iph->daddr);
 651        if (tunnel != NULL) {
 652                if (tunnel->parms.iph.protocol != IPPROTO_IPIP &&
 653                    tunnel->parms.iph.protocol != 0)
 654                        goto drop;
 655
 656                if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
 657                        goto drop;
 658                if (iptunnel_pull_header(skb, 0, tpi.proto))
 659                        goto drop;
 660                return ip_tunnel_rcv(tunnel, skb, &tpi, log_ecn_error);
 661        }
 662
 663        return 1;
 664
 665drop:
 666        kfree_skb(skb);
 667        return 0;
 668}
 669
 670/*
 671 * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
 672 * stores the embedded IPv4 address in v4dst and returns true.
 673 */
 674static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 675                      __be32 *v4dst)
 676{
 677#ifdef CONFIG_IPV6_SIT_6RD
 678        if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
 679                              tunnel->ip6rd.prefixlen)) {
 680                unsigned int pbw0, pbi0;
 681                int pbi1;
 682                u32 d;
 683
 684                pbw0 = tunnel->ip6rd.prefixlen >> 5;
 685                pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
 686
 687                d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
 688                    tunnel->ip6rd.relay_prefixlen;
 689
 690                pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
 691                if (pbi1 > 0)
 692                        d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
 693                             (32 - pbi1);
 694
 695                *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
 696                return true;
 697        }
 698#else
 699        if (v6dst->s6_addr16[0] == htons(0x2002)) {
 700                /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
 701                memcpy(v4dst, &v6dst->s6_addr16[1], 4);
 702                return true;
 703        }
 704#endif
 705        return false;
 706}
 707
 708static inline __be32 try_6rd(struct ip_tunnel *tunnel,
 709                             const struct in6_addr *v6dst)
 710{
 711        __be32 dst = 0;
 712        check_6rd(tunnel, v6dst, &dst);
 713        return dst;
 714}
 715
 716/*
 717 *      This function assumes it is being called from dev_queue_xmit()
 718 *      and that skb is filled properly by that function.
 719 */
 720
 721static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
 722                                     struct net_device *dev)
 723{
 724        struct ip_tunnel *tunnel = netdev_priv(dev);
 725        const struct iphdr  *tiph = &tunnel->parms.iph;
 726        const struct ipv6hdr *iph6 = ipv6_hdr(skb);
 727        u8     tos = tunnel->parms.iph.tos;
 728        __be16 df = tiph->frag_off;
 729        struct rtable *rt;                      /* Route to the other host */
 730        struct net_device *tdev;                /* Device to other host */
 731        unsigned int max_headroom;              /* The extra header space needed */
 732        __be32 dst = tiph->daddr;
 733        struct flowi4 fl4;
 734        int    mtu;
 735        const struct in6_addr *addr6;
 736        int addr_type;
 737        u8 ttl;
 738        int err;
 739
 740        if (skb->protocol != htons(ETH_P_IPV6))
 741                goto tx_error;
 742
 743        if (tos == 1)
 744                tos = ipv6_get_dsfield(iph6);
 745
 746        /* ISATAP (RFC4214) - must come before 6to4 */
 747        if (dev->priv_flags & IFF_ISATAP) {
 748                struct neighbour *neigh = NULL;
 749                bool do_tx_error = false;
 750
 751                if (skb_dst(skb))
 752                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 753
 754                if (neigh == NULL) {
 755                        net_dbg_ratelimited("sit: nexthop == NULL\n");
 756                        goto tx_error;
 757                }
 758
 759                addr6 = (const struct in6_addr *)&neigh->primary_key;
 760                addr_type = ipv6_addr_type(addr6);
 761
 762                if ((addr_type & IPV6_ADDR_UNICAST) &&
 763                     ipv6_addr_is_isatap(addr6))
 764                        dst = addr6->s6_addr32[3];
 765                else
 766                        do_tx_error = true;
 767
 768                neigh_release(neigh);
 769                if (do_tx_error)
 770                        goto tx_error;
 771        }
 772
 773        if (!dst)
 774                dst = try_6rd(tunnel, &iph6->daddr);
 775
 776        if (!dst) {
 777                struct neighbour *neigh = NULL;
 778                bool do_tx_error = false;
 779
 780                if (skb_dst(skb))
 781                        neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
 782
 783                if (neigh == NULL) {
 784                        net_dbg_ratelimited("sit: nexthop == NULL\n");
 785                        goto tx_error;
 786                }
 787
 788                addr6 = (const struct in6_addr *)&neigh->primary_key;
 789                addr_type = ipv6_addr_type(addr6);
 790
 791                if (addr_type == IPV6_ADDR_ANY) {
 792                        addr6 = &ipv6_hdr(skb)->daddr;
 793                        addr_type = ipv6_addr_type(addr6);
 794                }
 795
 796                if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
 797                        dst = addr6->s6_addr32[3];
 798                else
 799                        do_tx_error = true;
 800
 801                neigh_release(neigh);
 802                if (do_tx_error)
 803                        goto tx_error;
 804        }
 805
 806        rt = ip_route_output_ports(tunnel->net, &fl4, NULL,
 807                                   dst, tiph->saddr,
 808                                   0, 0,
 809                                   IPPROTO_IPV6, RT_TOS(tos),
 810                                   tunnel->parms.link);
 811        if (IS_ERR(rt)) {
 812                dev->stats.tx_carrier_errors++;
 813                goto tx_error_icmp;
 814        }
 815        if (rt->rt_type != RTN_UNICAST) {
 816                ip_rt_put(rt);
 817                dev->stats.tx_carrier_errors++;
 818                goto tx_error_icmp;
 819        }
 820        tdev = rt->dst.dev;
 821
 822        if (tdev == dev) {
 823                ip_rt_put(rt);
 824                dev->stats.collisions++;
 825                goto tx_error;
 826        }
 827
 828        if (df) {
 829                mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 830
 831                if (mtu < 68) {
 832                        dev->stats.collisions++;
 833                        ip_rt_put(rt);
 834                        goto tx_error;
 835                }
 836
 837                if (mtu < IPV6_MIN_MTU) {
 838                        mtu = IPV6_MIN_MTU;
 839                        df = 0;
 840                }
 841
 842                if (tunnel->parms.iph.daddr && skb_dst(skb))
 843                        skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 844
 845                if (skb->len > mtu) {
 846                        icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 847                        ip_rt_put(rt);
 848                        goto tx_error;
 849                }
 850        }
 851
 852        if (tunnel->err_count > 0) {
 853                if (time_before(jiffies,
 854                                tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 855                        tunnel->err_count--;
 856                        dst_link_failure(skb);
 857                } else
 858                        tunnel->err_count = 0;
 859        }
 860
 861        if (tunnel->net != dev_net(dev))
 862                skb_scrub_packet(skb);
 863
 864        /*
 865         * Okay, now see if we can stuff it in the buffer as-is.
 866         */
 867        max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
 868
 869        if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 870            (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 871                struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 872                if (!new_skb) {
 873                        ip_rt_put(rt);
 874                        dev->stats.tx_dropped++;
 875                        dev_kfree_skb(skb);
 876                        return NETDEV_TX_OK;
 877                }
 878                if (skb->sk)
 879                        skb_set_owner_w(new_skb, skb->sk);
 880                dev_kfree_skb(skb);
 881                skb = new_skb;
 882                iph6 = ipv6_hdr(skb);
 883        }
 884        ttl = tiph->ttl;
 885        if (ttl == 0)
 886                ttl = iph6->hop_limit;
 887        tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
 888
 889        if (likely(!skb->encapsulation)) {
 890                skb_reset_inner_headers(skb);
 891                skb->encapsulation = 1;
 892        }
 893
 894        err = iptunnel_xmit(dev_net(dev), rt, skb, fl4.saddr, fl4.daddr,
 895                            IPPROTO_IPV6, tos, ttl, df);
 896        iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 897        return NETDEV_TX_OK;
 898
 899tx_error_icmp:
 900        dst_link_failure(skb);
 901tx_error:
 902        dev->stats.tx_errors++;
 903        dev_kfree_skb(skb);
 904        return NETDEV_TX_OK;
 905}
 906
 907static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 908{
 909        struct ip_tunnel *tunnel = netdev_priv(dev);
 910        const struct iphdr  *tiph = &tunnel->parms.iph;
 911
 912        if (likely(!skb->encapsulation)) {
 913                skb_reset_inner_headers(skb);
 914                skb->encapsulation = 1;
 915        }
 916
 917        ip_tunnel_xmit(skb, dev, tiph, IPPROTO_IPIP);
 918        return NETDEV_TX_OK;
 919}
 920
 921static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
 922                                   struct net_device *dev)
 923{
 924        switch (skb->protocol) {
 925        case htons(ETH_P_IP):
 926                ipip_tunnel_xmit(skb, dev);
 927                break;
 928        case htons(ETH_P_IPV6):
 929                ipip6_tunnel_xmit(skb, dev);
 930                break;
 931        default:
 932                goto tx_err;
 933        }
 934
 935        return NETDEV_TX_OK;
 936
 937tx_err:
 938        dev->stats.tx_errors++;
 939        dev_kfree_skb(skb);
 940        return NETDEV_TX_OK;
 941
 942}
 943
 944static void ipip6_tunnel_bind_dev(struct net_device *dev)
 945{
 946        struct net_device *tdev = NULL;
 947        struct ip_tunnel *tunnel;
 948        const struct iphdr *iph;
 949        struct flowi4 fl4;
 950
 951        tunnel = netdev_priv(dev);
 952        iph = &tunnel->parms.iph;
 953
 954        if (iph->daddr) {
 955                struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
 956                                                          NULL,
 957                                                          iph->daddr, iph->saddr,
 958                                                          0, 0,
 959                                                          IPPROTO_IPV6,
 960                                                          RT_TOS(iph->tos),
 961                                                          tunnel->parms.link);
 962
 963                if (!IS_ERR(rt)) {
 964                        tdev = rt->dst.dev;
 965                        ip_rt_put(rt);
 966                }
 967                dev->flags |= IFF_POINTOPOINT;
 968        }
 969
 970        if (!tdev && tunnel->parms.link)
 971                tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
 972
 973        if (tdev) {
 974                dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 975                dev->mtu = tdev->mtu - sizeof(struct iphdr);
 976                if (dev->mtu < IPV6_MIN_MTU)
 977                        dev->mtu = IPV6_MIN_MTU;
 978        }
 979        dev->iflink = tunnel->parms.link;
 980}
 981
 982static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
 983{
 984        struct net *net = t->net;
 985        struct sit_net *sitn = net_generic(net, sit_net_id);
 986
 987        ipip6_tunnel_unlink(sitn, t);
 988        synchronize_net();
 989        t->parms.iph.saddr = p->iph.saddr;
 990        t->parms.iph.daddr = p->iph.daddr;
 991        memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
 992        memcpy(t->dev->broadcast, &p->iph.daddr, 4);
 993        ipip6_tunnel_link(sitn, t);
 994        t->parms.iph.ttl = p->iph.ttl;
 995        t->parms.iph.tos = p->iph.tos;
 996        if (t->parms.link != p->link) {
 997                t->parms.link = p->link;
 998                ipip6_tunnel_bind_dev(t->dev);
 999        }
1000        netdev_state_change(t->dev);
1001}
1002
1003#ifdef CONFIG_IPV6_SIT_6RD
1004static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1005                                   struct ip_tunnel_6rd *ip6rd)
1006{
1007        struct in6_addr prefix;
1008        __be32 relay_prefix;
1009
1010        if (ip6rd->relay_prefixlen > 32 ||
1011            ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1012                return -EINVAL;
1013
1014        ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1015        if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1016                return -EINVAL;
1017        if (ip6rd->relay_prefixlen)
1018                relay_prefix = ip6rd->relay_prefix &
1019                               htonl(0xffffffffUL <<
1020                                     (32 - ip6rd->relay_prefixlen));
1021        else
1022                relay_prefix = 0;
1023        if (relay_prefix != ip6rd->relay_prefix)
1024                return -EINVAL;
1025
1026        t->ip6rd.prefix = prefix;
1027        t->ip6rd.relay_prefix = relay_prefix;
1028        t->ip6rd.prefixlen = ip6rd->prefixlen;
1029        t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1030        netdev_state_change(t->dev);
1031        return 0;
1032}
1033#endif
1034
1035static int
1036ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
1037{
1038        int err = 0;
1039        struct ip_tunnel_parm p;
1040        struct ip_tunnel_prl prl;
1041        struct ip_tunnel *t;
1042        struct net *net = dev_net(dev);
1043        struct sit_net *sitn = net_generic(net, sit_net_id);
1044#ifdef CONFIG_IPV6_SIT_6RD
1045        struct ip_tunnel_6rd ip6rd;
1046#endif
1047
1048        switch (cmd) {
1049        case SIOCGETTUNNEL:
1050#ifdef CONFIG_IPV6_SIT_6RD
1051        case SIOCGET6RD:
1052#endif
1053                t = NULL;
1054                if (dev == sitn->fb_tunnel_dev) {
1055                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1056                                err = -EFAULT;
1057                                break;
1058                        }
1059                        t = ipip6_tunnel_locate(net, &p, 0);
1060                }
1061                if (t == NULL)
1062                        t = netdev_priv(dev);
1063
1064                err = -EFAULT;
1065                if (cmd == SIOCGETTUNNEL) {
1066                        memcpy(&p, &t->parms, sizeof(p));
1067                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1068                                         sizeof(p)))
1069                                goto done;
1070#ifdef CONFIG_IPV6_SIT_6RD
1071                } else {
1072                        ip6rd.prefix = t->ip6rd.prefix;
1073                        ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1074                        ip6rd.prefixlen = t->ip6rd.prefixlen;
1075                        ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1076                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1077                                         sizeof(ip6rd)))
1078                                goto done;
1079#endif
1080                }
1081                err = 0;
1082                break;
1083
1084        case SIOCADDTUNNEL:
1085        case SIOCCHGTUNNEL:
1086                err = -EPERM;
1087                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1088                        goto done;
1089
1090                err = -EFAULT;
1091                if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1092                        goto done;
1093
1094                err = -EINVAL;
1095                if (p.iph.protocol != IPPROTO_IPV6 &&
1096                    p.iph.protocol != IPPROTO_IPIP &&
1097                    p.iph.protocol != 0)
1098                        goto done;
1099                if (p.iph.version != 4 ||
1100                    p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1101                        goto done;
1102                if (p.iph.ttl)
1103                        p.iph.frag_off |= htons(IP_DF);
1104
1105                t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1106
1107                if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1108                        if (t != NULL) {
1109                                if (t->dev != dev) {
1110                                        err = -EEXIST;
1111                                        break;
1112                                }
1113                        } else {
1114                                if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1115                                    (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1116                                        err = -EINVAL;
1117                                        break;
1118                                }
1119                                t = netdev_priv(dev);
1120                        }
1121
1122                        ipip6_tunnel_update(t, &p);
1123                }
1124
1125                if (t) {
1126                        err = 0;
1127                        if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1128                                err = -EFAULT;
1129                } else
1130                        err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1131                break;
1132
1133        case SIOCDELTUNNEL:
1134                err = -EPERM;
1135                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1136                        goto done;
1137
1138                if (dev == sitn->fb_tunnel_dev) {
1139                        err = -EFAULT;
1140                        if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1141                                goto done;
1142                        err = -ENOENT;
1143                        if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1144                                goto done;
1145                        err = -EPERM;
1146                        if (t == netdev_priv(sitn->fb_tunnel_dev))
1147                                goto done;
1148                        dev = t->dev;
1149                }
1150                unregister_netdevice(dev);
1151                err = 0;
1152                break;
1153
1154        case SIOCGETPRL:
1155                err = -EINVAL;
1156                if (dev == sitn->fb_tunnel_dev)
1157                        goto done;
1158                err = -ENOENT;
1159                if (!(t = netdev_priv(dev)))
1160                        goto done;
1161                err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1162                break;
1163
1164        case SIOCADDPRL:
1165        case SIOCDELPRL:
1166        case SIOCCHGPRL:
1167                err = -EPERM;
1168                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1169                        goto done;
1170                err = -EINVAL;
1171                if (dev == sitn->fb_tunnel_dev)
1172                        goto done;
1173                err = -EFAULT;
1174                if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1175                        goto done;
1176                err = -ENOENT;
1177                if (!(t = netdev_priv(dev)))
1178                        goto done;
1179
1180                switch (cmd) {
1181                case SIOCDELPRL:
1182                        err = ipip6_tunnel_del_prl(t, &prl);
1183                        break;
1184                case SIOCADDPRL:
1185                case SIOCCHGPRL:
1186                        err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1187                        break;
1188                }
1189                netdev_state_change(dev);
1190                break;
1191
1192#ifdef CONFIG_IPV6_SIT_6RD
1193        case SIOCADD6RD:
1194        case SIOCCHG6RD:
1195        case SIOCDEL6RD:
1196                err = -EPERM;
1197                if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1198                        goto done;
1199
1200                err = -EFAULT;
1201                if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1202                                   sizeof(ip6rd)))
1203                        goto done;
1204
1205                t = netdev_priv(dev);
1206
1207                if (cmd != SIOCDEL6RD) {
1208                        err = ipip6_tunnel_update_6rd(t, &ip6rd);
1209                        if (err < 0)
1210                                goto done;
1211                } else
1212                        ipip6_tunnel_clone_6rd(dev, sitn);
1213
1214                err = 0;
1215                break;
1216#endif
1217
1218        default:
1219                err = -EINVAL;
1220        }
1221
1222done:
1223        return err;
1224}
1225
1226static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1227{
1228        if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1229                return -EINVAL;
1230        dev->mtu = new_mtu;
1231        return 0;
1232}
1233
1234static const struct net_device_ops ipip6_netdev_ops = {
1235        .ndo_uninit     = ipip6_tunnel_uninit,
1236        .ndo_start_xmit = sit_tunnel_xmit,
1237        .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1238        .ndo_change_mtu = ipip6_tunnel_change_mtu,
1239        .ndo_get_stats64 = ip_tunnel_get_stats64,
1240};
1241
1242static void ipip6_dev_free(struct net_device *dev)
1243{
1244        free_percpu(dev->tstats);
1245        free_netdev(dev);
1246}
1247
1248static void ipip6_tunnel_setup(struct net_device *dev)
1249{
1250        dev->netdev_ops         = &ipip6_netdev_ops;
1251        dev->destructor         = ipip6_dev_free;
1252
1253        dev->type               = ARPHRD_SIT;
1254        dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1255        dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1256        dev->flags              = IFF_NOARP;
1257        dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1258        dev->iflink             = 0;
1259        dev->addr_len           = 4;
1260        dev->features           |= NETIF_F_LLTX;
1261}
1262
1263static int ipip6_tunnel_init(struct net_device *dev)
1264{
1265        struct ip_tunnel *tunnel = netdev_priv(dev);
1266
1267        tunnel->dev = dev;
1268        tunnel->net = dev_net(dev);
1269
1270        memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1271        memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1272
1273        ipip6_tunnel_bind_dev(dev);
1274        dev->tstats = alloc_percpu(struct pcpu_tstats);
1275        if (!dev->tstats)
1276                return -ENOMEM;
1277
1278        return 0;
1279}
1280
1281static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1282{
1283        struct ip_tunnel *tunnel = netdev_priv(dev);
1284        struct iphdr *iph = &tunnel->parms.iph;
1285        struct net *net = dev_net(dev);
1286        struct sit_net *sitn = net_generic(net, sit_net_id);
1287
1288        tunnel->dev = dev;
1289        tunnel->net = dev_net(dev);
1290        strcpy(tunnel->parms.name, dev->name);
1291
1292        iph->version            = 4;
1293        iph->protocol           = IPPROTO_IPV6;
1294        iph->ihl                = 5;
1295        iph->ttl                = 64;
1296
1297        dev->tstats = alloc_percpu(struct pcpu_tstats);
1298        if (!dev->tstats)
1299                return -ENOMEM;
1300        dev_hold(dev);
1301        rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1302        return 0;
1303}
1304
1305static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[])
1306{
1307        u8 proto;
1308
1309        if (!data || !data[IFLA_IPTUN_PROTO])
1310                return 0;
1311
1312        proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1313        if (proto != IPPROTO_IPV6 &&
1314            proto != IPPROTO_IPIP &&
1315            proto != 0)
1316                return -EINVAL;
1317
1318        return 0;
1319}
1320
1321static void ipip6_netlink_parms(struct nlattr *data[],
1322                                struct ip_tunnel_parm *parms)
1323{
1324        memset(parms, 0, sizeof(*parms));
1325
1326        parms->iph.version = 4;
1327        parms->iph.protocol = IPPROTO_IPV6;
1328        parms->iph.ihl = 5;
1329        parms->iph.ttl = 64;
1330
1331        if (!data)
1332                return;
1333
1334        if (data[IFLA_IPTUN_LINK])
1335                parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1336
1337        if (data[IFLA_IPTUN_LOCAL])
1338                parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1339
1340        if (data[IFLA_IPTUN_REMOTE])
1341                parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1342
1343        if (data[IFLA_IPTUN_TTL]) {
1344                parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1345                if (parms->iph.ttl)
1346                        parms->iph.frag_off = htons(IP_DF);
1347        }
1348
1349        if (data[IFLA_IPTUN_TOS])
1350                parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1351
1352        if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1353                parms->iph.frag_off = htons(IP_DF);
1354
1355        if (data[IFLA_IPTUN_FLAGS])
1356                parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1357
1358        if (data[IFLA_IPTUN_PROTO])
1359                parms->iph.protocol = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1360
1361}
1362
1363#ifdef CONFIG_IPV6_SIT_6RD
1364/* This function returns true when 6RD attributes are present in the nl msg */
1365static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1366                                    struct ip_tunnel_6rd *ip6rd)
1367{
1368        bool ret = false;
1369        memset(ip6rd, 0, sizeof(*ip6rd));
1370
1371        if (!data)
1372                return ret;
1373
1374        if (data[IFLA_IPTUN_6RD_PREFIX]) {
1375                ret = true;
1376                nla_memcpy(&ip6rd->prefix, data[IFLA_IPTUN_6RD_PREFIX],
1377                           sizeof(struct in6_addr));
1378        }
1379
1380        if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1381                ret = true;
1382                ip6rd->relay_prefix =
1383                        nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1384        }
1385
1386        if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1387                ret = true;
1388                ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1389        }
1390
1391        if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1392                ret = true;
1393                ip6rd->relay_prefixlen =
1394                        nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1395        }
1396
1397        return ret;
1398}
1399#endif
1400
1401static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1402                         struct nlattr *tb[], struct nlattr *data[])
1403{
1404        struct net *net = dev_net(dev);
1405        struct ip_tunnel *nt;
1406#ifdef CONFIG_IPV6_SIT_6RD
1407        struct ip_tunnel_6rd ip6rd;
1408#endif
1409        int err;
1410
1411        nt = netdev_priv(dev);
1412        ipip6_netlink_parms(data, &nt->parms);
1413
1414        if (ipip6_tunnel_locate(net, &nt->parms, 0))
1415                return -EEXIST;
1416
1417        err = ipip6_tunnel_create(dev);
1418        if (err < 0)
1419                return err;
1420
1421#ifdef CONFIG_IPV6_SIT_6RD
1422        if (ipip6_netlink_6rd_parms(data, &ip6rd))
1423                err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1424#endif
1425
1426        return err;
1427}
1428
1429static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1430                          struct nlattr *data[])
1431{
1432        struct ip_tunnel *t = netdev_priv(dev);
1433        struct ip_tunnel_parm p;
1434        struct net *net = t->net;
1435        struct sit_net *sitn = net_generic(net, sit_net_id);
1436#ifdef CONFIG_IPV6_SIT_6RD
1437        struct ip_tunnel_6rd ip6rd;
1438#endif
1439
1440        if (dev == sitn->fb_tunnel_dev)
1441                return -EINVAL;
1442
1443        ipip6_netlink_parms(data, &p);
1444
1445        if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1446            (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1447                return -EINVAL;
1448
1449        t = ipip6_tunnel_locate(net, &p, 0);
1450
1451        if (t) {
1452                if (t->dev != dev)
1453                        return -EEXIST;
1454        } else
1455                t = netdev_priv(dev);
1456
1457        ipip6_tunnel_update(t, &p);
1458
1459#ifdef CONFIG_IPV6_SIT_6RD
1460        if (ipip6_netlink_6rd_parms(data, &ip6rd))
1461                return ipip6_tunnel_update_6rd(t, &ip6rd);
1462#endif
1463
1464        return 0;
1465}
1466
1467static size_t ipip6_get_size(const struct net_device *dev)
1468{
1469        return
1470                /* IFLA_IPTUN_LINK */
1471                nla_total_size(4) +
1472                /* IFLA_IPTUN_LOCAL */
1473                nla_total_size(4) +
1474                /* IFLA_IPTUN_REMOTE */
1475                nla_total_size(4) +
1476                /* IFLA_IPTUN_TTL */
1477                nla_total_size(1) +
1478                /* IFLA_IPTUN_TOS */
1479                nla_total_size(1) +
1480                /* IFLA_IPTUN_PMTUDISC */
1481                nla_total_size(1) +
1482                /* IFLA_IPTUN_FLAGS */
1483                nla_total_size(2) +
1484                /* IFLA_IPTUN_PROTO */
1485                nla_total_size(1) +
1486#ifdef CONFIG_IPV6_SIT_6RD
1487                /* IFLA_IPTUN_6RD_PREFIX */
1488                nla_total_size(sizeof(struct in6_addr)) +
1489                /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1490                nla_total_size(4) +
1491                /* IFLA_IPTUN_6RD_PREFIXLEN */
1492                nla_total_size(2) +
1493                /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1494                nla_total_size(2) +
1495#endif
1496                0;
1497}
1498
1499static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1500{
1501        struct ip_tunnel *tunnel = netdev_priv(dev);
1502        struct ip_tunnel_parm *parm = &tunnel->parms;
1503
1504        if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1505            nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1506            nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1507            nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1508            nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1509            nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1510                       !!(parm->iph.frag_off & htons(IP_DF))) ||
1511            nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1512            nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1513                goto nla_put_failure;
1514
1515#ifdef CONFIG_IPV6_SIT_6RD
1516        if (nla_put(skb, IFLA_IPTUN_6RD_PREFIX, sizeof(struct in6_addr),
1517                    &tunnel->ip6rd.prefix) ||
1518            nla_put_be32(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1519                         tunnel->ip6rd.relay_prefix) ||
1520            nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1521                        tunnel->ip6rd.prefixlen) ||
1522            nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1523                        tunnel->ip6rd.relay_prefixlen))
1524                goto nla_put_failure;
1525#endif
1526
1527        return 0;
1528
1529nla_put_failure:
1530        return -EMSGSIZE;
1531}
1532
1533static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1534        [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1535        [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1536        [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1537        [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1538        [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1539        [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1540        [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1541        [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1542#ifdef CONFIG_IPV6_SIT_6RD
1543        [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1544        [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1545        [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1546        [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1547#endif
1548};
1549
1550static struct rtnl_link_ops sit_link_ops __read_mostly = {
1551        .kind           = "sit",
1552        .maxtype        = IFLA_IPTUN_MAX,
1553        .policy         = ipip6_policy,
1554        .priv_size      = sizeof(struct ip_tunnel),
1555        .setup          = ipip6_tunnel_setup,
1556        .validate       = ipip6_validate,
1557        .newlink        = ipip6_newlink,
1558        .changelink     = ipip6_changelink,
1559        .get_size       = ipip6_get_size,
1560        .fill_info      = ipip6_fill_info,
1561};
1562
1563static struct xfrm_tunnel sit_handler __read_mostly = {
1564        .handler        =       ipip6_rcv,
1565        .err_handler    =       ipip6_err,
1566        .priority       =       1,
1567};
1568
1569static struct xfrm_tunnel ipip_handler __read_mostly = {
1570        .handler        =       ipip_rcv,
1571        .err_handler    =       ipip6_err,
1572        .priority       =       2,
1573};
1574
1575static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1576{
1577        struct net *net = dev_net(sitn->fb_tunnel_dev);
1578        struct net_device *dev, *aux;
1579        int prio;
1580
1581        for_each_netdev_safe(net, dev, aux)
1582                if (dev->rtnl_link_ops == &sit_link_ops)
1583                        unregister_netdevice_queue(dev, head);
1584
1585        for (prio = 1; prio < 4; prio++) {
1586                int h;
1587                for (h = 0; h < HASH_SIZE; h++) {
1588                        struct ip_tunnel *t;
1589
1590                        t = rtnl_dereference(sitn->tunnels[prio][h]);
1591                        while (t != NULL) {
1592                                /* If dev is in the same netns, it has already
1593                                 * been added to the list by the previous loop.
1594                                 */
1595                                if (dev_net(t->dev) != net)
1596                                        unregister_netdevice_queue(t->dev,
1597                                                                   head);
1598                                t = rtnl_dereference(t->next);
1599                        }
1600                }
1601        }
1602}
1603
1604static int __net_init sit_init_net(struct net *net)
1605{
1606        struct sit_net *sitn = net_generic(net, sit_net_id);
1607        struct ip_tunnel *t;
1608        int err;
1609
1610        sitn->tunnels[0] = sitn->tunnels_wc;
1611        sitn->tunnels[1] = sitn->tunnels_l;
1612        sitn->tunnels[2] = sitn->tunnels_r;
1613        sitn->tunnels[3] = sitn->tunnels_r_l;
1614
1615        sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1616                                           ipip6_tunnel_setup);
1617        if (!sitn->fb_tunnel_dev) {
1618                err = -ENOMEM;
1619                goto err_alloc_dev;
1620        }
1621        dev_net_set(sitn->fb_tunnel_dev, net);
1622        /* FB netdevice is special: we have one, and only one per netns.
1623         * Allowing to move it to another netns is clearly unsafe.
1624         */
1625        sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1626
1627        err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1628        if (err)
1629                goto err_dev_free;
1630
1631        ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1632
1633        if ((err = register_netdev(sitn->fb_tunnel_dev)))
1634                goto err_reg_dev;
1635
1636        t = netdev_priv(sitn->fb_tunnel_dev);
1637
1638        strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1639        return 0;
1640
1641err_reg_dev:
1642        dev_put(sitn->fb_tunnel_dev);
1643err_dev_free:
1644        ipip6_dev_free(sitn->fb_tunnel_dev);
1645err_alloc_dev:
1646        return err;
1647}
1648
1649static void __net_exit sit_exit_net(struct net *net)
1650{
1651        struct sit_net *sitn = net_generic(net, sit_net_id);
1652        LIST_HEAD(list);
1653
1654        rtnl_lock();
1655        sit_destroy_tunnels(sitn, &list);
1656        unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1657        unregister_netdevice_many(&list);
1658        rtnl_unlock();
1659}
1660
1661static struct pernet_operations sit_net_ops = {
1662        .init = sit_init_net,
1663        .exit = sit_exit_net,
1664        .id   = &sit_net_id,
1665        .size = sizeof(struct sit_net),
1666};
1667
1668static void __exit sit_cleanup(void)
1669{
1670        rtnl_link_unregister(&sit_link_ops);
1671        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1672        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1673
1674        unregister_pernet_device(&sit_net_ops);
1675        rcu_barrier(); /* Wait for completion of call_rcu()'s */
1676}
1677
1678static int __init sit_init(void)
1679{
1680        int err;
1681
1682        pr_info("IPv6 over IPv4 tunneling driver\n");
1683
1684        err = register_pernet_device(&sit_net_ops);
1685        if (err < 0)
1686                return err;
1687        err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1688        if (err < 0) {
1689                pr_info("%s: can't register ip6ip4\n", __func__);
1690                goto xfrm_tunnel_failed;
1691        }
1692        err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1693        if (err < 0) {
1694                pr_info("%s: can't register ip4ip4\n", __func__);
1695                goto xfrm_tunnel4_failed;
1696        }
1697        err = rtnl_link_register(&sit_link_ops);
1698        if (err < 0)
1699                goto rtnl_link_failed;
1700
1701out:
1702        return err;
1703
1704rtnl_link_failed:
1705        xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1706xfrm_tunnel4_failed:
1707        xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1708xfrm_tunnel_failed:
1709        unregister_pernet_device(&sit_net_ops);
1710        goto out;
1711}
1712
1713module_init(sit_init);
1714module_exit(sit_cleanup);
1715MODULE_LICENSE("GPL");
1716MODULE_ALIAS_NETDEV("sit0");
1717