net/ipv4/ipip.c

   1 /*
   2  *      Linux NET3:     IP/IP protocol decoder.
   3  *
   4  *      Authors:
   5  *              Sam Lantinga (slouken@cs.ucdavis.edu)  02/01/95
   6  *
   7  *      Fixes:
   8  *              Alan Cox        :       Merged and made usable non modular (its so tiny its silly as
   9  *                                      a module taking up 2 pages).
  10  *              Alan Cox        :       Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph)
  11  *                                      to keep ip_forward happy.
  12  *              Alan Cox        :       More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8).
  13  *              Kai Schulte     :       Fixed #defines for IP_FIREWALL->FIREWALL
  14  *              David Woodhouse :       Perform some basic ICMP handling.
  15  *                                      IPIP Routing without decapsulation.
  16  *              Carlos Picoto   :       GRE over IP support
  17  *              Alexey Kuznetsov:       Reworked. Really, now it is truncated version of ipv4/ip_gre.c.
  18  *                                      I do not want to merge them together.
  19  *
  20  *      This program is free software; you can redistribute it and/or
  21  *      modify it under the terms of the GNU General Public License
  22  *      as published by the Free Software Foundation; either version
  23  *      2 of the License, or (at your option) any later version.
  24  *
  25  */
  26
  27 /* tunnel.c: an IP tunnel driver
  28
  29         The purpose of this driver is to provide an IP tunnel through
  30         which you can tunnel network traffic transparently across subnets.
  31
  32         This was written by looking at Nick Holloway's dummy driver
  33         Thanks for the great code!
  34
  35                 -Sam Lantinga   (slouken@cs.ucdavis.edu)  02/01/95
  36
  37         Minor tweaks:
  38                 Cleaned up the code a little and added some pre-1.3.0 tweaks.
  39                 dev->hard_header/hard_header_len changed to use no headers.
  40                 Comments/bracketing tweaked.
  41                 Made the tunnels use dev->name not tunnel: when error reporting.
  42                 Added tx_dropped stat
  43
  44                 -Alan Cox       (alan@lxorguk.ukuu.org.uk) 21 March 95
  45
  46         Reworked:
  47                 Changed to tunnel to destination gateway in addition to the
  48                         tunnel's pointopoint address
  49                 Almost completely rewritten
  50                 Note:  There is currently no firewall or ICMP handling done.
  51
  52                 -Sam Lantinga   (slouken@cs.ucdavis.edu) 02/13/96
  53
  54 */
  55
  56 /* Things I wish I had known when writing the tunnel driver:
  57
  58         When the tunnel_xmit() function is called, the skb contains the
  59         packet to be sent (plus a great deal of extra info), and dev
  60         contains the tunnel device that _we_ are.
  61
  62         When we are passed a packet, we are expected to fill in the
  63         source address with our source IP address.
  64
  65         What is the proper way to allocate, copy and free a buffer?
  66         After you allocate it, it is a "0 length" chunk of memory
  67         starting at zero.  If you want to add headers to the buffer
  68         later, you'll have to call "skb_reserve(skb, amount)" with
  69         the amount of memory you want reserved.  Then, you call
  70         "skb_put(skb, amount)" with the amount of space you want in
  71         the buffer.  skb_put() returns a pointer to the top (#0) of
  72         that buffer.  skb->len is set to the amount of space you have
  73         "allocated" with skb_put().  You can then write up to skb->len
  74         bytes to that buffer.  If you need more, you can call skb_put()
  75         again with the additional amount of space you need.  You can
  76         find out how much more space you can allocate by calling
  77         "skb_tailroom(skb)".
  78         Now, to add header space, call "skb_push(skb, header_len)".
  79         This creates space at the beginning of the buffer and returns
  80         a pointer to this new space.  If later you need to strip a
  81         header from a buffer, call "skb_pull(skb, header_len)".
  82         skb_headroom() will return how much space is left at the top
  83         of the buffer (before the main data).  Remember, this headroom
  84         space must be reserved before the skb_put() function is called.
  85         */
  86
  87 /*
  88    This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c
  89
  90    For comments look at net/ipv4/ip_gre.c --ANK
  91  */
  92
  93
  94 #include <linux/capability.h>
  95 #include <linux/module.h>
  96 #include <linux/types.h>
  97 #include <linux/kernel.h>
  98 #include <asm/uaccess.h>
  99 #include <linux/skbuff.h>
 100 #include <linux/netdevice.h>
 101 #include <linux/in.h>
 102 #include <linux/tcp.h>
 103 #include <linux/udp.h>
 104 #include <linux/if_arp.h>
 105 #include <linux/mroute.h>
 106 #include <linux/init.h>
 107 #include <linux/netfilter_ipv4.h>
 108 #include <linux/if_ether.h>
 109
 110 #include <net/sock.h>
 111 #include <net/ip.h>
 112 #include <net/icmp.h>
 113 #include <net/ipip.h>
 114 #include <net/inet_ecn.h>
 115 #include <net/xfrm.h>
 116 #include <net/net_namespace.h>
 117 #include <net/netns/generic.h>
 118
 119 #define HASH_SIZE  16
 120 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 121
 122 static int ipip_net_id __read_mostly;
 123 struct ipip_net {
 124         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
 125         struct ip_tunnel *tunnels_r[HASH_SIZE];
 126         struct ip_tunnel *tunnels_l[HASH_SIZE];
 127         struct ip_tunnel *tunnels_wc[1];
 128         struct ip_tunnel **tunnels[4];
 129
 130         struct net_device *fb_tunnel_dev;
 131 };
 132
 133 static void ipip_fb_tunnel_init(struct net_device *dev);
 134 static void ipip_tunnel_init(struct net_device *dev);
 135 static void ipip_tunnel_setup(struct net_device *dev);
 136
 137 /*
 138  * Locking : hash tables are protected by RCU and a spinlock
 139  */
 140 static DEFINE_SPINLOCK(ipip_lock);
 141
 142 #define for_each_ip_tunnel_rcu(start) \
 143         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 144
 145 static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
 146                 __be32 remote, __be32 local)
 147 {
 148         unsigned h0 = HASH(remote);
 149         unsigned h1 = HASH(local);
 150         struct ip_tunnel *t;
 151         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 152
 153         for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
 154                 if (local == t->parms.iph.saddr &&
 155                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
 156                         return t;
 157
 158         for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
 159                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
 160                         return t;
 161
 162         for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
 163                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
 164                         return t;
 165
 166         t = rcu_dereference(ipn->tunnels_wc[0]);
 167         if (t && (t->dev->flags&IFF_UP))
 168                 return t;
 169         return NULL;
 170 }
 171
 172 static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn,
 173                 struct ip_tunnel_parm *parms)
 174 {
 175         __be32 remote = parms->iph.daddr;
 176         __be32 local = parms->iph.saddr;
 177         unsigned h = 0;
 178         int prio = 0;
 179
 180         if (remote) {
 181                 prio |= 2;
 182                 h ^= HASH(remote);
 183         }
 184         if (local) {
 185                 prio |= 1;
 186                 h ^= HASH(local);
 187         }
 188         return &ipn->tunnels[prio][h];
 189 }
 190
 191 static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn,
 192                 struct ip_tunnel *t)
 193 {
 194         return __ipip_bucket(ipn, &t->parms);
 195 }
 196
 197 static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
 198 {
 199         struct ip_tunnel **tp;
 200
 201         for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {
 202                 if (t == *tp) {
 203                         spin_lock_bh(&ipip_lock);
 204                         *tp = t->next;
 205                         spin_unlock_bh(&ipip_lock);
 206                         break;
 207                 }
 208         }
 209 }
 210
 211 static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
 212 {
 213         struct ip_tunnel **tp = ipip_bucket(ipn, t);
 214
 215         spin_lock_bh(&ipip_lock);
 216         t->next = *tp;
 217         rcu_assign_pointer(*tp, t);
 218         spin_unlock_bh(&ipip_lock);
 219 }
 220
 221 static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
 222                 struct ip_tunnel_parm *parms, int create)
 223 {
 224         __be32 remote = parms->iph.daddr;
 225         __be32 local = parms->iph.saddr;
 226         struct ip_tunnel *t, **tp, *nt;
 227         struct net_device *dev;
 228         char name[IFNAMSIZ];
 229         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 230
 231         for (tp = __ipip_bucket(ipn, parms); (t = *tp) != NULL; tp = &t->next) {
 232                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
 233                         return t;
 234         }
 235         if (!create)
 236                 return NULL;
 237
 238         if (parms->name[0])
 239                 strlcpy(name, parms->name, IFNAMSIZ);
 240         else
 241                 sprintf(name, "tunl%%d");
 242
 243         dev = alloc_netdev(sizeof(*t), name, ipip_tunnel_setup);
 244         if (dev == NULL)
 245                 return NULL;
 246
 247         dev_net_set(dev, net);
 248
 249         if (strchr(name, '%')) {
 250                 if (dev_alloc_name(dev, name) < 0)
 251                         goto failed_free;
 252         }
 253
 254         nt = netdev_priv(dev);
 255         nt->parms = *parms;
 256
 257         ipip_tunnel_init(dev);
 258
 259         if (register_netdevice(dev) < 0)
 260                 goto failed_free;
 261
 262         dev_hold(dev);
 263         ipip_tunnel_link(ipn, nt);
 264         return nt;
 265
 266 failed_free:
 267         free_netdev(dev);
 268         return NULL;
 269 }
 270
 271 static void ipip_tunnel_uninit(struct net_device *dev)
 272 {
 273         struct net *net = dev_net(dev);
 274         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 275
 276         if (dev == ipn->fb_tunnel_dev) {
 277                 spin_lock_bh(&ipip_lock);
 278                 ipn->tunnels_wc[0] = NULL;
 279                 spin_unlock_bh(&ipip_lock);
 280         } else
 281                 ipip_tunnel_unlink(ipn, netdev_priv(dev));
 282         dev_put(dev);
 283 }
 284
 285 static int ipip_err(struct sk_buff *skb, u32 info)
 286 {
 287
 288 /* All the routers (except for Linux) return only
 289    8 bytes of packet payload. It means, that precise relaying of
 290    ICMP in the real Internet is absolutely infeasible.
 291  */
 292         struct iphdr *iph = (struct iphdr *)skb->data;
 293         const int type = icmp_hdr(skb)->type;
 294         const int code = icmp_hdr(skb)->code;
 295         struct ip_tunnel *t;
 296         int err;
 297
 298         switch (type) {
 299         default:
 300         case ICMP_PARAMETERPROB:
 301                 return 0;
 302
 303         case ICMP_DEST_UNREACH:
 304                 switch (code) {
 305                 case ICMP_SR_FAILED:
 306                 case ICMP_PORT_UNREACH:
 307                         /* Impossible event. */
 308                         return 0;
 309                 case ICMP_FRAG_NEEDED:
 310                         /* Soft state for pmtu is maintained by IP core. */
 311                         return 0;
 312                 default:
 313                         /* All others are translated to HOST_UNREACH.
 314                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 315                            I believe they are just ether pollution. --ANK
 316                          */
 317                         break;
 318                 }
 319                 break;
 320         case ICMP_TIME_EXCEEDED:
 321                 if (code != ICMP_EXC_TTL)
 322                         return 0;
 323                 break;
 324         }
 325
 326         err = -ENOENT;
 327
 328         rcu_read_lock();
 329         t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
 330         if (t == NULL || t->parms.iph.daddr == 0)
 331                 goto out;
 332
 333         err = 0;
 334         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 335                 goto out;
 336
 337         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 338                 t->err_count++;
 339         else
 340                 t->err_count = 1;
 341         t->err_time = jiffies;
 342 out:
 343         rcu_read_unlock();
 344         return err;
 345 }
 346
 347 static inline void ipip_ecn_decapsulate(const struct iphdr *outer_iph,
 348                                         struct sk_buff *skb)
 349 {
 350         struct iphdr *inner_iph = ip_hdr(skb);
 351
 352         if (INET_ECN_is_ce(outer_iph->tos))
 353                 IP_ECN_set_ce(inner_iph);
 354 }
 355
 356 static int ipip_rcv(struct sk_buff *skb)
 357 {
 358         struct ip_tunnel *tunnel;
 359         const struct iphdr *iph = ip_hdr(skb);
 360
 361         rcu_read_lock();
 362         if ((tunnel = ipip_tunnel_lookup(dev_net(skb->dev),
 363                                         iph->saddr, iph->daddr)) != NULL) {
 364                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 365                         rcu_read_unlock();
 366                         kfree_skb(skb);
 367                         return 0;
 368                 }
 369
 370                 secpath_reset(skb);
 371
 372                 skb->mac_header = skb->network_header;
 373                 skb_reset_network_header(skb);
 374                 skb->protocol = htons(ETH_P_IP);
 375                 skb->pkt_type = PACKET_HOST;
 376
 377                 tunnel->dev->stats.rx_packets++;
 378                 tunnel->dev->stats.rx_bytes += skb->len;
 379                 skb->dev = tunnel->dev;
 380                 skb_dst_drop(skb);
 381                 nf_reset(skb);
 382                 ipip_ecn_decapsulate(iph, skb);
 383                 netif_rx(skb);
 384                 rcu_read_unlock();
 385                 return 0;
 386         }
 387         rcu_read_unlock();
 388
 389         return -1;
 390 }
 391
 392 /*
 393  *      This function assumes it is being called from dev_queue_xmit()
 394  *      and that skb is filled properly by that function.
 395  */
 396
 397 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 398 {
 399         struct ip_tunnel *tunnel = netdev_priv(dev);
 400         struct net_device_stats *stats = &dev->stats;
 401         struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
 402         struct iphdr  *tiph = &tunnel->parms.iph;
 403         u8     tos = tunnel->parms.iph.tos;
 404         __be16 df = tiph->frag_off;
 405         struct rtable *rt;                      /* Route to the other host */
 406         struct net_device *tdev;                        /* Device to other host */
 407         struct iphdr  *old_iph = ip_hdr(skb);
 408         struct iphdr  *iph;                     /* Our new IP header */
 409         unsigned int max_headroom;              /* The extra header space needed */
 410         __be32 dst = tiph->daddr;
 411         int    mtu;
 412
 413         if (skb->protocol != htons(ETH_P_IP))
 414                 goto tx_error;
 415
 416         if (tos&1)
 417                 tos = old_iph->tos;
 418
 419         if (!dst) {
 420                 /* NBMA tunnel */
 421                 if ((rt = skb_rtable(skb)) == NULL) {
 422                         stats->tx_fifo_errors++;
 423                         goto tx_error;
 424                 }
 425                 if ((dst = rt->rt_gateway) == 0)
 426                         goto tx_error_icmp;
 427         }
 428
 429         {
 430                 struct flowi fl = { .oif = tunnel->parms.link,
 431                                     .nl_u = { .ip4_u =
 432                                               { .daddr = dst,
 433                                                 .saddr = tiph->saddr,
 434                                                 .tos = RT_TOS(tos) } },
 435                                     .proto = IPPROTO_IPIP };
 436                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 437                         stats->tx_carrier_errors++;
 438                         goto tx_error_icmp;
 439                 }
 440         }
 441         tdev = rt->u.dst.dev;
 442
 443         if (tdev == dev) {
 444                 ip_rt_put(rt);
 445                 stats->collisions++;
 446                 goto tx_error;
 447         }
 448
 449         df |= old_iph->frag_off & htons(IP_DF);
 450
 451         if (df) {
 452                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
 453
 454                 if (mtu < 68) {
 455                         stats->collisions++;
 456                         ip_rt_put(rt);
 457                         goto tx_error;
 458                 }
 459
 460                 if (skb_dst(skb))
 461                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 462
 463                 if ((old_iph->frag_off & htons(IP_DF)) &&
 464                     mtu < ntohs(old_iph->tot_len)) {
 465                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 466                                   htonl(mtu));
 467                         ip_rt_put(rt);
 468                         goto tx_error;
 469                 }
 470         }
 471
 472         if (tunnel->err_count > 0) {
 473                 if (time_before(jiffies,
 474                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 475                         tunnel->err_count--;
 476                         dst_link_failure(skb);
 477                 } else
 478                         tunnel->err_count = 0;
 479         }
 480
 481         /*
 482          * Okay, now see if we can stuff it in the buffer as-is.
 483          */
 484         max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
 485
 486         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 487             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 488                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 489                 if (!new_skb) {
 490                         ip_rt_put(rt);
 491                         txq->tx_dropped++;
 492                         dev_kfree_skb(skb);
 493                         return NETDEV_TX_OK;
 494                 }
 495                 if (skb->sk)
 496                         skb_set_owner_w(new_skb, skb->sk);
 497                 dev_kfree_skb(skb);
 498                 skb = new_skb;
 499                 old_iph = ip_hdr(skb);
 500         }
 501
 502         skb->transport_header = skb->network_header;
 503         skb_push(skb, sizeof(struct iphdr));
 504         skb_reset_network_header(skb);
 505         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 506         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 507                               IPSKB_REROUTED);
 508         skb_dst_drop(skb);
 509         skb_dst_set(skb, &rt->u.dst);
 510
 511         /*
 512          *      Push down and install the IPIP header.
 513          */
 514
 515         iph                     =       ip_hdr(skb);
 516         iph->version            =       4;
 517         iph->ihl                =       sizeof(struct iphdr)>>2;
 518         iph->frag_off           =       df;
 519         iph->protocol           =       IPPROTO_IPIP;
 520         iph->tos                =       INET_ECN_encapsulate(tos, old_iph->tos);
 521         iph->daddr              =       rt->rt_dst;
 522         iph->saddr              =       rt->rt_src;
 523
 524         if ((iph->ttl = tiph->ttl) == 0)
 525                 iph->ttl        =       old_iph->ttl;
 526
 527         nf_reset(skb);
 528
 529         IPTUNNEL_XMIT();
 530         return NETDEV_TX_OK;
 531
 532 tx_error_icmp:
 533         dst_link_failure(skb);
 534 tx_error:
 535         stats->tx_errors++;
 536         dev_kfree_skb(skb);
 537         return NETDEV_TX_OK;
 538 }
 539
 540 static void ipip_tunnel_bind_dev(struct net_device *dev)
 541 {
 542         struct net_device *tdev = NULL;
 543         struct ip_tunnel *tunnel;
 544         struct iphdr *iph;
 545
 546         tunnel = netdev_priv(dev);
 547         iph = &tunnel->parms.iph;
 548
 549         if (iph->daddr) {
 550                 struct flowi fl = { .oif = tunnel->parms.link,
 551                                     .nl_u = { .ip4_u =
 552                                               { .daddr = iph->daddr,
 553                                                 .saddr = iph->saddr,
 554                                                 .tos = RT_TOS(iph->tos) } },
 555                                     .proto = IPPROTO_IPIP };
 556                 struct rtable *rt;
 557                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 558                         tdev = rt->u.dst.dev;
 559                         ip_rt_put(rt);
 560                 }
 561                 dev->flags |= IFF_POINTOPOINT;
 562         }
 563
 564         if (!tdev && tunnel->parms.link)
 565                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 566
 567         if (tdev) {
 568                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 569                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 570         }
 571         dev->iflink = tunnel->parms.link;
 572 }
 573
 574 static int
 575 ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 576 {
 577         int err = 0;
 578         struct ip_tunnel_parm p;
 579         struct ip_tunnel *t;
 580         struct net *net = dev_net(dev);
 581         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 582
 583         switch (cmd) {
 584         case SIOCGETTUNNEL:
 585                 t = NULL;
 586                 if (dev == ipn->fb_tunnel_dev) {
 587                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 588                                 err = -EFAULT;
 589                                 break;
 590                         }
 591                         t = ipip_tunnel_locate(net, &p, 0);
 592                 }
 593                 if (t == NULL)
 594                         t = netdev_priv(dev);
 595                 memcpy(&p, &t->parms, sizeof(p));
 596                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 597                         err = -EFAULT;
 598                 break;
 599
 600         case SIOCADDTUNNEL:
 601         case SIOCCHGTUNNEL:
 602                 err = -EPERM;
 603                 if (!capable(CAP_NET_ADMIN))
 604                         goto done;
 605
 606                 err = -EFAULT;
 607                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 608                         goto done;
 609
 610                 err = -EINVAL;
 611                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 612                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 613                         goto done;
 614                 if (p.iph.ttl)
 615                         p.iph.frag_off |= htons(IP_DF);
 616
 617                 t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 618
 619                 if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 620                         if (t != NULL) {
 621                                 if (t->dev != dev) {
 622                                         err = -EEXIST;
 623                                         break;
 624                                 }
 625                         } else {
 626                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 627                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 628                                         err = -EINVAL;
 629                                         break;
 630                                 }
 631                                 t = netdev_priv(dev);
 632                                 ipip_tunnel_unlink(ipn, t);
 633                                 t->parms.iph.saddr = p.iph.saddr;
 634                                 t->parms.iph.daddr = p.iph.daddr;
 635                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 636                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 637                                 ipip_tunnel_link(ipn, t);
 638                                 netdev_state_change(dev);
 639                         }
 640                 }
 641
 642                 if (t) {
 643                         err = 0;
 644                         if (cmd == SIOCCHGTUNNEL) {
 645                                 t->parms.iph.ttl = p.iph.ttl;
 646                                 t->parms.iph.tos = p.iph.tos;
 647                                 t->parms.iph.frag_off = p.iph.frag_off;
 648                                 if (t->parms.link != p.link) {
 649                                         t->parms.link = p.link;
 650                                         ipip_tunnel_bind_dev(dev);
 651                                         netdev_state_change(dev);
 652                                 }
 653                         }
 654                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 655                                 err = -EFAULT;
 656                 } else
 657                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 658                 break;
 659
 660         case SIOCDELTUNNEL:
 661                 err = -EPERM;
 662                 if (!capable(CAP_NET_ADMIN))
 663                         goto done;
 664
 665                 if (dev == ipn->fb_tunnel_dev) {
 666                         err = -EFAULT;
 667                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 668                                 goto done;
 669                         err = -ENOENT;
 670                         if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
 671                                 goto done;
 672                         err = -EPERM;
 673                         if (t->dev == ipn->fb_tunnel_dev)
 674                                 goto done;
 675                         dev = t->dev;
 676                 }
 677                 unregister_netdevice(dev);
 678                 err = 0;
 679                 break;
 680
 681         default:
 682                 err = -EINVAL;
 683         }
 684
 685 done:
 686         return err;
 687 }
 688
 689 static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 690 {
 691         if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 692                 return -EINVAL;
 693         dev->mtu = new_mtu;
 694         return 0;
 695 }
 696
 697 static const struct net_device_ops ipip_netdev_ops = {
 698         .ndo_uninit     = ipip_tunnel_uninit,
 699         .ndo_start_xmit = ipip_tunnel_xmit,
 700         .ndo_do_ioctl   = ipip_tunnel_ioctl,
 701         .ndo_change_mtu = ipip_tunnel_change_mtu,
 702
 703 };
 704
 705 static void ipip_tunnel_setup(struct net_device *dev)
 706 {
 707         dev->netdev_ops         = &ipip_netdev_ops;
 708         dev->destructor         = free_netdev;
 709
 710         dev->type               = ARPHRD_TUNNEL;
 711         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 712         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 713         dev->flags              = IFF_NOARP;
 714         dev->iflink             = 0;
 715         dev->addr_len           = 4;
 716         dev->features           |= NETIF_F_NETNS_LOCAL;
 717         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 718 }
 719
 720 static void ipip_tunnel_init(struct net_device *dev)
 721 {
 722         struct ip_tunnel *tunnel = netdev_priv(dev);
 723
 724         tunnel->dev = dev;
 725         strcpy(tunnel->parms.name, dev->name);
 726
 727         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 728         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 729
 730         ipip_tunnel_bind_dev(dev);
 731 }
 732
 733 static void ipip_fb_tunnel_init(struct net_device *dev)
 734 {
 735         struct ip_tunnel *tunnel = netdev_priv(dev);
 736         struct iphdr *iph = &tunnel->parms.iph;
 737         struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
 738
 739         tunnel->dev = dev;
 740         strcpy(tunnel->parms.name, dev->name);
 741
 742         iph->version            = 4;
 743         iph->protocol           = IPPROTO_IPIP;
 744         iph->ihl                = 5;
 745
 746         dev_hold(dev);
 747         ipn->tunnels_wc[0]      = tunnel;
 748 }
 749
 750 static struct xfrm_tunnel ipip_handler = {
 751         .handler        =       ipip_rcv,
 752         .err_handler    =       ipip_err,
 753         .priority       =       1,
 754 };
 755
 756 static const char banner[] __initconst =
 757         KERN_INFO "IPv4 over IPv4 tunneling driver\n";
 758
 759 static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
 760 {
 761         int prio;
 762
 763         for (prio = 1; prio < 4; prio++) {
 764                 int h;
 765                 for (h = 0; h < HASH_SIZE; h++) {
 766                         struct ip_tunnel *t = ipn->tunnels[prio][h];
 767
 768                         while (t != NULL) {
 769                                 unregister_netdevice_queue(t->dev, head);
 770                                 t = t->next;
 771                         }
 772                 }
 773         }
 774 }
 775
 776 static int ipip_init_net(struct net *net)
 777 {
 778         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 779         int err;
 780
 781         ipn->tunnels[0] = ipn->tunnels_wc;
 782         ipn->tunnels[1] = ipn->tunnels_l;
 783         ipn->tunnels[2] = ipn->tunnels_r;
 784         ipn->tunnels[3] = ipn->tunnels_r_l;
 785
 786         ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
 787                                            "tunl0",
 788                                            ipip_tunnel_setup);
 789         if (!ipn->fb_tunnel_dev) {
 790                 err = -ENOMEM;
 791                 goto err_alloc_dev;
 792         }
 793         dev_net_set(ipn->fb_tunnel_dev, net);
 794
 795         ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
 796
 797         if ((err = register_netdev(ipn->fb_tunnel_dev)))
 798                 goto err_reg_dev;
 799
 800         return 0;
 801
 802 err_reg_dev:
 803         free_netdev(ipn->fb_tunnel_dev);
 804 err_alloc_dev:
 805         /* nothing */
 806         return err;
 807 }
 808
 809 static void ipip_exit_net(struct net *net)
 810 {
 811         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 812         LIST_HEAD(list);
 813
 814         rtnl_lock();
 815         ipip_destroy_tunnels(ipn, &list);
 816         unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
 817         unregister_netdevice_many(&list);
 818         rtnl_unlock();
 819 }
 820
 821 static struct pernet_operations ipip_net_ops = {
 822         .init = ipip_init_net,
 823         .exit = ipip_exit_net,
 824         .id   = &ipip_net_id,
 825         .size = sizeof(struct ipip_net),
 826 };
 827
 828 static int __init ipip_init(void)
 829 {
 830         int err;
 831
 832         printk(banner);
 833
 834         if (xfrm4_tunnel_register(&ipip_handler, AF_INET)) {
 835                 printk(KERN_INFO "ipip init: can't register tunnel\n");
 836                 return -EAGAIN;
 837         }
 838
 839         err = register_pernet_device(&ipip_net_ops);
 840         if (err)
 841                 xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
 842
 843         return err;
 844 }
 845
 846 static void __exit ipip_fini(void)
 847 {
 848         if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
 849                 printk(KERN_INFO "ipip close: can't deregister tunnel\n");
 850
 851         unregister_pernet_device(&ipip_net_ops);
 852 }
 853
 854 module_init(ipip_init);
 855 module_exit(ipip_fini);
 856 MODULE_LICENSE("GPL");