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 <linux/slab.h>
  99 #include <asm/uaccess.h>
 100 #include <linux/skbuff.h>
 101 #include <linux/netdevice.h>
 102 #include <linux/in.h>
 103 #include <linux/tcp.h>
 104 #include <linux/udp.h>
 105 #include <linux/if_arp.h>
 106 #include <linux/mroute.h>
 107 #include <linux/init.h>
 108 #include <linux/netfilter_ipv4.h>
 109 #include <linux/if_ether.h>
 110
 111 #include <net/sock.h>
 112 #include <net/ip.h>
 113 #include <net/icmp.h>
 114 #include <net/ipip.h>
 115 #include <net/inet_ecn.h>
 116 #include <net/xfrm.h>
 117 #include <net/net_namespace.h>
 118 #include <net/netns/generic.h>
 119
 120 #define HASH_SIZE  16
 121 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 122
 123 static int ipip_net_id __read_mostly;
 124 struct ipip_net {
 125         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
 126         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
 127         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
 128         struct ip_tunnel __rcu *tunnels_wc[1];
 129         struct ip_tunnel __rcu **tunnels[4];
 130
 131         struct net_device *fb_tunnel_dev;
 132 };
 133
 134 static int ipip_tunnel_init(struct net_device *dev);
 135 static void ipip_tunnel_setup(struct net_device *dev);
 136 static void ipip_dev_free(struct net_device *dev);
 137
 138 /*
 139  * Locking : hash tables are protected by RCU and RTNL
 140  */
 141
 142 #define for_each_ip_tunnel_rcu(start) \
 143         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 144
 145 /* often modified stats are per cpu, other are shared (netdev->stats) */
 146 struct pcpu_tstats {
 147         unsigned long   rx_packets;
 148         unsigned long   rx_bytes;
 149         unsigned long   tx_packets;
 150         unsigned long   tx_bytes;
 151 };
 152
 153 static struct net_device_stats *ipip_get_stats(struct net_device *dev)
 154 {
 155         struct pcpu_tstats sum = { 0 };
 156         int i;
 157
 158         for_each_possible_cpu(i) {
 159                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 160
 161                 sum.rx_packets += tstats->rx_packets;
 162                 sum.rx_bytes   += tstats->rx_bytes;
 163                 sum.tx_packets += tstats->tx_packets;
 164                 sum.tx_bytes   += tstats->tx_bytes;
 165         }
 166         dev->stats.rx_packets = sum.rx_packets;
 167         dev->stats.rx_bytes   = sum.rx_bytes;
 168         dev->stats.tx_packets = sum.tx_packets;
 169         dev->stats.tx_bytes   = sum.tx_bytes;
 170         return &dev->stats;
 171 }
 172
 173 static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
 174                 __be32 remote, __be32 local)
 175 {
 176         unsigned int h0 = HASH(remote);
 177         unsigned int h1 = HASH(local);
 178         struct ip_tunnel *t;
 179         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 180
 181         for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
 182                 if (local == t->parms.iph.saddr &&
 183                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
 184                         return t;
 185
 186         for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
 187                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
 188                         return t;
 189
 190         for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
 191                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
 192                         return t;
 193
 194         t = rcu_dereference(ipn->tunnels_wc[0]);
 195         if (t && (t->dev->flags&IFF_UP))
 196                 return t;
 197         return NULL;
 198 }
 199
 200 static struct ip_tunnel __rcu **__ipip_bucket(struct ipip_net *ipn,
 201                 struct ip_tunnel_parm *parms)
 202 {
 203         __be32 remote = parms->iph.daddr;
 204         __be32 local = parms->iph.saddr;
 205         unsigned int h = 0;
 206         int prio = 0;
 207
 208         if (remote) {
 209                 prio |= 2;
 210                 h ^= HASH(remote);
 211         }
 212         if (local) {
 213                 prio |= 1;
 214                 h ^= HASH(local);
 215         }
 216         return &ipn->tunnels[prio][h];
 217 }
 218
 219 static inline struct ip_tunnel __rcu **ipip_bucket(struct ipip_net *ipn,
 220                 struct ip_tunnel *t)
 221 {
 222         return __ipip_bucket(ipn, &t->parms);
 223 }
 224
 225 static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
 226 {
 227         struct ip_tunnel __rcu **tp;
 228         struct ip_tunnel *iter;
 229
 230         for (tp = ipip_bucket(ipn, t);
 231              (iter = rtnl_dereference(*tp)) != NULL;
 232              tp = &iter->next) {
 233                 if (t == iter) {
 234                         rcu_assign_pointer(*tp, t->next);
 235                         break;
 236                 }
 237         }
 238 }
 239
 240 static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
 241 {
 242         struct ip_tunnel __rcu **tp = ipip_bucket(ipn, t);
 243
 244         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 245         rcu_assign_pointer(*tp, t);
 246 }
 247
 248 static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
 249                 struct ip_tunnel_parm *parms, int create)
 250 {
 251         __be32 remote = parms->iph.daddr;
 252         __be32 local = parms->iph.saddr;
 253         struct ip_tunnel *t, *nt;
 254         struct ip_tunnel __rcu **tp;
 255         struct net_device *dev;
 256         char name[IFNAMSIZ];
 257         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 258
 259         for (tp = __ipip_bucket(ipn, parms);
 260                  (t = rtnl_dereference(*tp)) != NULL;
 261                  tp = &t->next) {
 262                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
 263                         return t;
 264         }
 265         if (!create)
 266                 return NULL;
 267
 268         if (parms->name[0])
 269                 strlcpy(name, parms->name, IFNAMSIZ);
 270         else
 271                 strcpy(name, "tunl%d");
 272
 273         dev = alloc_netdev(sizeof(*t), name, ipip_tunnel_setup);
 274         if (dev == NULL)
 275                 return NULL;
 276
 277         dev_net_set(dev, net);
 278
 279         if (strchr(name, '%')) {
 280                 if (dev_alloc_name(dev, name) < 0)
 281                         goto failed_free;
 282         }
 283
 284         nt = netdev_priv(dev);
 285         nt->parms = *parms;
 286
 287         if (ipip_tunnel_init(dev) < 0)
 288                 goto failed_free;
 289
 290         if (register_netdevice(dev) < 0)
 291                 goto failed_free;
 292
 293         dev_hold(dev);
 294         ipip_tunnel_link(ipn, nt);
 295         return nt;
 296
 297 failed_free:
 298         ipip_dev_free(dev);
 299         return NULL;
 300 }
 301
 302 /* called with RTNL */
 303 static void ipip_tunnel_uninit(struct net_device *dev)
 304 {
 305         struct net *net = dev_net(dev);
 306         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 307
 308         if (dev == ipn->fb_tunnel_dev)
 309                 rcu_assign_pointer(ipn->tunnels_wc[0], NULL);
 310         else
 311                 ipip_tunnel_unlink(ipn, netdev_priv(dev));
 312         dev_put(dev);
 313 }
 314
 315 static int ipip_err(struct sk_buff *skb, u32 info)
 316 {
 317
 318 /* All the routers (except for Linux) return only
 319    8 bytes of packet payload. It means, that precise relaying of
 320    ICMP in the real Internet is absolutely infeasible.
 321  */
 322         struct iphdr *iph = (struct iphdr *)skb->data;
 323         const int type = icmp_hdr(skb)->type;
 324         const int code = icmp_hdr(skb)->code;
 325         struct ip_tunnel *t;
 326         int err;
 327
 328         switch (type) {
 329         default:
 330         case ICMP_PARAMETERPROB:
 331                 return 0;
 332
 333         case ICMP_DEST_UNREACH:
 334                 switch (code) {
 335                 case ICMP_SR_FAILED:
 336                 case ICMP_PORT_UNREACH:
 337                         /* Impossible event. */
 338                         return 0;
 339                 case ICMP_FRAG_NEEDED:
 340                         /* Soft state for pmtu is maintained by IP core. */
 341                         return 0;
 342                 default:
 343                         /* All others are translated to HOST_UNREACH.
 344                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 345                            I believe they are just ether pollution. --ANK
 346                          */
 347                         break;
 348                 }
 349                 break;
 350         case ICMP_TIME_EXCEEDED:
 351                 if (code != ICMP_EXC_TTL)
 352                         return 0;
 353                 break;
 354         }
 355
 356         err = -ENOENT;
 357
 358         rcu_read_lock();
 359         t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
 360         if (t == NULL || t->parms.iph.daddr == 0)
 361                 goto out;
 362
 363         err = 0;
 364         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 365                 goto out;
 366
 367         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 368                 t->err_count++;
 369         else
 370                 t->err_count = 1;
 371         t->err_time = jiffies;
 372 out:
 373         rcu_read_unlock();
 374         return err;
 375 }
 376
 377 static inline void ipip_ecn_decapsulate(const struct iphdr *outer_iph,
 378                                         struct sk_buff *skb)
 379 {
 380         struct iphdr *inner_iph = ip_hdr(skb);
 381
 382         if (INET_ECN_is_ce(outer_iph->tos))
 383                 IP_ECN_set_ce(inner_iph);
 384 }
 385
 386 static int ipip_rcv(struct sk_buff *skb)
 387 {
 388         struct ip_tunnel *tunnel;
 389         const struct iphdr *iph = ip_hdr(skb);
 390
 391         rcu_read_lock();
 392         tunnel = ipip_tunnel_lookup(dev_net(skb->dev), iph->saddr, iph->daddr);
 393         if (tunnel != NULL) {
 394                 struct pcpu_tstats *tstats;
 395
 396                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
 397                         rcu_read_unlock();
 398                         kfree_skb(skb);
 399                         return 0;
 400                 }
 401
 402                 secpath_reset(skb);
 403
 404                 skb->mac_header = skb->network_header;
 405                 skb_reset_network_header(skb);
 406                 skb->protocol = htons(ETH_P_IP);
 407                 skb->pkt_type = PACKET_HOST;
 408
 409                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 410                 tstats->rx_packets++;
 411                 tstats->rx_bytes += skb->len;
 412
 413                 __skb_tunnel_rx(skb, tunnel->dev);
 414
 415                 ipip_ecn_decapsulate(iph, skb);
 416
 417                 netif_rx(skb);
 418
 419                 rcu_read_unlock();
 420                 return 0;
 421         }
 422         rcu_read_unlock();
 423
 424         return -1;
 425 }
 426
 427 /*
 428  *      This function assumes it is being called from dev_queue_xmit()
 429  *      and that skb is filled properly by that function.
 430  */
 431
 432 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 433 {
 434         struct ip_tunnel *tunnel = netdev_priv(dev);
 435         struct pcpu_tstats *tstats;
 436         struct iphdr  *tiph = &tunnel->parms.iph;
 437         u8     tos = tunnel->parms.iph.tos;
 438         __be16 df = tiph->frag_off;
 439         struct rtable *rt;                      /* Route to the other host */
 440         struct net_device *tdev;                /* Device to other host */
 441         struct iphdr  *old_iph = ip_hdr(skb);
 442         struct iphdr  *iph;                     /* Our new IP header */
 443         unsigned int max_headroom;              /* The extra header space needed */
 444         __be32 dst = tiph->daddr;
 445         int    mtu;
 446
 447         if (skb->protocol != htons(ETH_P_IP))
 448                 goto tx_error;
 449
 450         if (tos & 1)
 451                 tos = old_iph->tos;
 452
 453         if (!dst) {
 454                 /* NBMA tunnel */
 455                 if ((rt = skb_rtable(skb)) == NULL) {
 456                         dev->stats.tx_fifo_errors++;
 457                         goto tx_error;
 458                 }
 459                 if ((dst = rt->rt_gateway) == 0)
 460                         goto tx_error_icmp;
 461         }
 462
 463         {
 464                 struct flowi fl = {
 465                         .oif = tunnel->parms.link,
 466                         .nl_u = {
 467                                 .ip4_u = {
 468                                         .daddr = dst,
 469                                         .saddr = tiph->saddr,
 470                                         .tos = RT_TOS(tos)
 471                                 }
 472                         },
 473                         .proto = IPPROTO_IPIP
 474                 };
 475
 476                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 477                         dev->stats.tx_carrier_errors++;
 478                         goto tx_error_icmp;
 479                 }
 480         }
 481         tdev = rt->dst.dev;
 482
 483         if (tdev == dev) {
 484                 ip_rt_put(rt);
 485                 dev->stats.collisions++;
 486                 goto tx_error;
 487         }
 488
 489         df |= old_iph->frag_off & htons(IP_DF);
 490
 491         if (df) {
 492                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 493
 494                 if (mtu < 68) {
 495                         dev->stats.collisions++;
 496                         ip_rt_put(rt);
 497                         goto tx_error;
 498                 }
 499
 500                 if (skb_dst(skb))
 501                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 502
 503                 if ((old_iph->frag_off & htons(IP_DF)) &&
 504                     mtu < ntohs(old_iph->tot_len)) {
 505                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 506                                   htonl(mtu));
 507                         ip_rt_put(rt);
 508                         goto tx_error;
 509                 }
 510         }
 511
 512         if (tunnel->err_count > 0) {
 513                 if (time_before(jiffies,
 514                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 515                         tunnel->err_count--;
 516                         dst_link_failure(skb);
 517                 } else
 518                         tunnel->err_count = 0;
 519         }
 520
 521         /*
 522          * Okay, now see if we can stuff it in the buffer as-is.
 523          */
 524         max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
 525
 526         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 527             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 528                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 529                 if (!new_skb) {
 530                         ip_rt_put(rt);
 531                         dev->stats.tx_dropped++;
 532                         dev_kfree_skb(skb);
 533                         return NETDEV_TX_OK;
 534                 }
 535                 if (skb->sk)
 536                         skb_set_owner_w(new_skb, skb->sk);
 537                 dev_kfree_skb(skb);
 538                 skb = new_skb;
 539                 old_iph = ip_hdr(skb);
 540         }
 541
 542         skb->transport_header = skb->network_header;
 543         skb_push(skb, sizeof(struct iphdr));
 544         skb_reset_network_header(skb);
 545         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 546         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 547                               IPSKB_REROUTED);
 548         skb_dst_drop(skb);
 549         skb_dst_set(skb, &rt->dst);
 550
 551         /*
 552          *      Push down and install the IPIP header.
 553          */
 554
 555         iph                     =       ip_hdr(skb);
 556         iph->version            =       4;
 557         iph->ihl                =       sizeof(struct iphdr)>>2;
 558         iph->frag_off           =       df;
 559         iph->protocol           =       IPPROTO_IPIP;
 560         iph->tos                =       INET_ECN_encapsulate(tos, old_iph->tos);
 561         iph->daddr              =       rt->rt_dst;
 562         iph->saddr              =       rt->rt_src;
 563
 564         if ((iph->ttl = tiph->ttl) == 0)
 565                 iph->ttl        =       old_iph->ttl;
 566
 567         nf_reset(skb);
 568         tstats = this_cpu_ptr(dev->tstats);
 569         __IPTUNNEL_XMIT(tstats, &dev->stats);
 570         return NETDEV_TX_OK;
 571
 572 tx_error_icmp:
 573         dst_link_failure(skb);
 574 tx_error:
 575         dev->stats.tx_errors++;
 576         dev_kfree_skb(skb);
 577         return NETDEV_TX_OK;
 578 }
 579
 580 static void ipip_tunnel_bind_dev(struct net_device *dev)
 581 {
 582         struct net_device *tdev = NULL;
 583         struct ip_tunnel *tunnel;
 584         struct iphdr *iph;
 585
 586         tunnel = netdev_priv(dev);
 587         iph = &tunnel->parms.iph;
 588
 589         if (iph->daddr) {
 590                 struct flowi fl = {
 591                         .oif = tunnel->parms.link,
 592                         .nl_u = {
 593                                 .ip4_u = {
 594                                         .daddr = iph->daddr,
 595                                         .saddr = iph->saddr,
 596                                         .tos = RT_TOS(iph->tos)
 597                                 }
 598                         },
 599                         .proto = IPPROTO_IPIP
 600                 };
 601                 struct rtable *rt;
 602
 603                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 604                         tdev = rt->dst.dev;
 605                         ip_rt_put(rt);
 606                 }
 607                 dev->flags |= IFF_POINTOPOINT;
 608         }
 609
 610         if (!tdev && tunnel->parms.link)
 611                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 612
 613         if (tdev) {
 614                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 615                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 616         }
 617         dev->iflink = tunnel->parms.link;
 618 }
 619
 620 static int
 621 ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 622 {
 623         int err = 0;
 624         struct ip_tunnel_parm p;
 625         struct ip_tunnel *t;
 626         struct net *net = dev_net(dev);
 627         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 628
 629         switch (cmd) {
 630         case SIOCGETTUNNEL:
 631                 t = NULL;
 632                 if (dev == ipn->fb_tunnel_dev) {
 633                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 634                                 err = -EFAULT;
 635                                 break;
 636                         }
 637                         t = ipip_tunnel_locate(net, &p, 0);
 638                 }
 639                 if (t == NULL)
 640                         t = netdev_priv(dev);
 641                 memcpy(&p, &t->parms, sizeof(p));
 642                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 643                         err = -EFAULT;
 644                 break;
 645
 646         case SIOCADDTUNNEL:
 647         case SIOCCHGTUNNEL:
 648                 err = -EPERM;
 649                 if (!capable(CAP_NET_ADMIN))
 650                         goto done;
 651
 652                 err = -EFAULT;
 653                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 654                         goto done;
 655
 656                 err = -EINVAL;
 657                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 658                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 659                         goto done;
 660                 if (p.iph.ttl)
 661                         p.iph.frag_off |= htons(IP_DF);
 662
 663                 t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 664
 665                 if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 666                         if (t != NULL) {
 667                                 if (t->dev != dev) {
 668                                         err = -EEXIST;
 669                                         break;
 670                                 }
 671                         } else {
 672                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 673                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 674                                         err = -EINVAL;
 675                                         break;
 676                                 }
 677                                 t = netdev_priv(dev);
 678                                 ipip_tunnel_unlink(ipn, t);
 679                                 synchronize_net();
 680                                 t->parms.iph.saddr = p.iph.saddr;
 681                                 t->parms.iph.daddr = p.iph.daddr;
 682                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 683                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 684                                 ipip_tunnel_link(ipn, t);
 685                                 netdev_state_change(dev);
 686                         }
 687                 }
 688
 689                 if (t) {
 690                         err = 0;
 691                         if (cmd == SIOCCHGTUNNEL) {
 692                                 t->parms.iph.ttl = p.iph.ttl;
 693                                 t->parms.iph.tos = p.iph.tos;
 694                                 t->parms.iph.frag_off = p.iph.frag_off;
 695                                 if (t->parms.link != p.link) {
 696                                         t->parms.link = p.link;
 697                                         ipip_tunnel_bind_dev(dev);
 698                                         netdev_state_change(dev);
 699                                 }
 700                         }
 701                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 702                                 err = -EFAULT;
 703                 } else
 704                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 705                 break;
 706
 707         case SIOCDELTUNNEL:
 708                 err = -EPERM;
 709                 if (!capable(CAP_NET_ADMIN))
 710                         goto done;
 711
 712                 if (dev == ipn->fb_tunnel_dev) {
 713                         err = -EFAULT;
 714                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 715                                 goto done;
 716                         err = -ENOENT;
 717                         if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
 718                                 goto done;
 719                         err = -EPERM;
 720                         if (t->dev == ipn->fb_tunnel_dev)
 721                                 goto done;
 722                         dev = t->dev;
 723                 }
 724                 unregister_netdevice(dev);
 725                 err = 0;
 726                 break;
 727
 728         default:
 729                 err = -EINVAL;
 730         }
 731
 732 done:
 733         return err;
 734 }
 735
 736 static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 737 {
 738         if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 739                 return -EINVAL;
 740         dev->mtu = new_mtu;
 741         return 0;
 742 }
 743
 744 static const struct net_device_ops ipip_netdev_ops = {
 745         .ndo_uninit     = ipip_tunnel_uninit,
 746         .ndo_start_xmit = ipip_tunnel_xmit,
 747         .ndo_do_ioctl   = ipip_tunnel_ioctl,
 748         .ndo_change_mtu = ipip_tunnel_change_mtu,
 749         .ndo_get_stats  = ipip_get_stats,
 750 };
 751
 752 static void ipip_dev_free(struct net_device *dev)
 753 {
 754         free_percpu(dev->tstats);
 755         free_netdev(dev);
 756 }
 757
 758 static void ipip_tunnel_setup(struct net_device *dev)
 759 {
 760         dev->netdev_ops         = &ipip_netdev_ops;
 761         dev->destructor         = ipip_dev_free;
 762
 763         dev->type               = ARPHRD_TUNNEL;
 764         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 765         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 766         dev->flags              = IFF_NOARP;
 767         dev->iflink             = 0;
 768         dev->addr_len           = 4;
 769         dev->features           |= NETIF_F_NETNS_LOCAL;
 770         dev->features           |= NETIF_F_LLTX;
 771         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 772 }
 773
 774 static int ipip_tunnel_init(struct net_device *dev)
 775 {
 776         struct ip_tunnel *tunnel = netdev_priv(dev);
 777
 778         tunnel->dev = dev;
 779         strcpy(tunnel->parms.name, dev->name);
 780
 781         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 782         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 783
 784         ipip_tunnel_bind_dev(dev);
 785
 786         dev->tstats = alloc_percpu(struct pcpu_tstats);
 787         if (!dev->tstats)
 788                 return -ENOMEM;
 789
 790         return 0;
 791 }
 792
 793 static int __net_init ipip_fb_tunnel_init(struct net_device *dev)
 794 {
 795         struct ip_tunnel *tunnel = netdev_priv(dev);
 796         struct iphdr *iph = &tunnel->parms.iph;
 797         struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
 798
 799         tunnel->dev = dev;
 800         strcpy(tunnel->parms.name, dev->name);
 801
 802         iph->version            = 4;
 803         iph->protocol           = IPPROTO_IPIP;
 804         iph->ihl                = 5;
 805
 806         dev->tstats = alloc_percpu(struct pcpu_tstats);
 807         if (!dev->tstats)
 808                 return -ENOMEM;
 809
 810         dev_hold(dev);
 811         rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
 812         return 0;
 813 }
 814
 815 static struct xfrm_tunnel ipip_handler __read_mostly = {
 816         .handler        =       ipip_rcv,
 817         .err_handler    =       ipip_err,
 818         .priority       =       1,
 819 };
 820
 821 static const char banner[] __initconst =
 822         KERN_INFO "IPv4 over IPv4 tunneling driver\n";
 823
 824 static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
 825 {
 826         int prio;
 827
 828         for (prio = 1; prio < 4; prio++) {
 829                 int h;
 830                 for (h = 0; h < HASH_SIZE; h++) {
 831                         struct ip_tunnel *t;
 832
 833                         t = rtnl_dereference(ipn->tunnels[prio][h]);
 834                         while (t != NULL) {
 835                                 unregister_netdevice_queue(t->dev, head);
 836                                 t = rtnl_dereference(t->next);
 837                         }
 838                 }
 839         }
 840 }
 841
 842 static int __net_init ipip_init_net(struct net *net)
 843 {
 844         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 845         int err;
 846
 847         ipn->tunnels[0] = ipn->tunnels_wc;
 848         ipn->tunnels[1] = ipn->tunnels_l;
 849         ipn->tunnels[2] = ipn->tunnels_r;
 850         ipn->tunnels[3] = ipn->tunnels_r_l;
 851
 852         ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
 853                                            "tunl0",
 854                                            ipip_tunnel_setup);
 855         if (!ipn->fb_tunnel_dev) {
 856                 err = -ENOMEM;
 857                 goto err_alloc_dev;
 858         }
 859         dev_net_set(ipn->fb_tunnel_dev, net);
 860
 861         err = ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
 862         if (err)
 863                 goto err_reg_dev;
 864
 865         if ((err = register_netdev(ipn->fb_tunnel_dev)))
 866                 goto err_reg_dev;
 867
 868         return 0;
 869
 870 err_reg_dev:
 871         ipip_dev_free(ipn->fb_tunnel_dev);
 872 err_alloc_dev:
 873         /* nothing */
 874         return err;
 875 }
 876
 877 static void __net_exit ipip_exit_net(struct net *net)
 878 {
 879         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 880         LIST_HEAD(list);
 881
 882         rtnl_lock();
 883         ipip_destroy_tunnels(ipn, &list);
 884         unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
 885         unregister_netdevice_many(&list);
 886         rtnl_unlock();
 887 }
 888
 889 static struct pernet_operations ipip_net_ops = {
 890         .init = ipip_init_net,
 891         .exit = ipip_exit_net,
 892         .id   = &ipip_net_id,
 893         .size = sizeof(struct ipip_net),
 894 };
 895
 896 static int __init ipip_init(void)
 897 {
 898         int err;
 899
 900         printk(banner);
 901
 902         err = register_pernet_device(&ipip_net_ops);
 903         if (err < 0)
 904                 return err;
 905         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
 906         if (err < 0) {
 907                 unregister_pernet_device(&ipip_net_ops);
 908                 printk(KERN_INFO "ipip init: can't register tunnel\n");
 909         }
 910         return err;
 911 }
 912
 913 static void __exit ipip_fini(void)
 914 {
 915         if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
 916                 printk(KERN_INFO "ipip close: can't deregister tunnel\n");
 917
 918         unregister_pernet_device(&ipip_net_ops);
 919 }
 920
 921 module_init(ipip_init);
 922 module_exit(ipip_fini);
 923 MODULE_LICENSE("GPL");