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         rt = ip_route_output_ports(dev_net(dev), NULL,
 464                                    dst, tiph->saddr,
 465                                    0, 0,
 466                                    IPPROTO_IPIP, RT_TOS(tos),
 467                                    tunnel->parms.link);
 468         if (IS_ERR(rt)) {
 469                 dev->stats.tx_carrier_errors++;
 470                 goto tx_error_icmp;
 471         }
 472         tdev = rt->dst.dev;
 473
 474         if (tdev == dev) {
 475                 ip_rt_put(rt);
 476                 dev->stats.collisions++;
 477                 goto tx_error;
 478         }
 479
 480         df |= old_iph->frag_off & htons(IP_DF);
 481
 482         if (df) {
 483                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 484
 485                 if (mtu < 68) {
 486                         dev->stats.collisions++;
 487                         ip_rt_put(rt);
 488                         goto tx_error;
 489                 }
 490
 491                 if (skb_dst(skb))
 492                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 493
 494                 if ((old_iph->frag_off & htons(IP_DF)) &&
 495                     mtu < ntohs(old_iph->tot_len)) {
 496                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 497                                   htonl(mtu));
 498                         ip_rt_put(rt);
 499                         goto tx_error;
 500                 }
 501         }
 502
 503         if (tunnel->err_count > 0) {
 504                 if (time_before(jiffies,
 505                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 506                         tunnel->err_count--;
 507                         dst_link_failure(skb);
 508                 } else
 509                         tunnel->err_count = 0;
 510         }
 511
 512         /*
 513          * Okay, now see if we can stuff it in the buffer as-is.
 514          */
 515         max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
 516
 517         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 518             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 519                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 520                 if (!new_skb) {
 521                         ip_rt_put(rt);
 522                         dev->stats.tx_dropped++;
 523                         dev_kfree_skb(skb);
 524                         return NETDEV_TX_OK;
 525                 }
 526                 if (skb->sk)
 527                         skb_set_owner_w(new_skb, skb->sk);
 528                 dev_kfree_skb(skb);
 529                 skb = new_skb;
 530                 old_iph = ip_hdr(skb);
 531         }
 532
 533         skb->transport_header = skb->network_header;
 534         skb_push(skb, sizeof(struct iphdr));
 535         skb_reset_network_header(skb);
 536         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 537         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 538                               IPSKB_REROUTED);
 539         skb_dst_drop(skb);
 540         skb_dst_set(skb, &rt->dst);
 541
 542         /*
 543          *      Push down and install the IPIP header.
 544          */
 545
 546         iph                     =       ip_hdr(skb);
 547         iph->version            =       4;
 548         iph->ihl                =       sizeof(struct iphdr)>>2;
 549         iph->frag_off           =       df;
 550         iph->protocol           =       IPPROTO_IPIP;
 551         iph->tos                =       INET_ECN_encapsulate(tos, old_iph->tos);
 552         iph->daddr              =       rt->rt_dst;
 553         iph->saddr              =       rt->rt_src;
 554
 555         if ((iph->ttl = tiph->ttl) == 0)
 556                 iph->ttl        =       old_iph->ttl;
 557
 558         nf_reset(skb);
 559         tstats = this_cpu_ptr(dev->tstats);
 560         __IPTUNNEL_XMIT(tstats, &dev->stats);
 561         return NETDEV_TX_OK;
 562
 563 tx_error_icmp:
 564         dst_link_failure(skb);
 565 tx_error:
 566         dev->stats.tx_errors++;
 567         dev_kfree_skb(skb);
 568         return NETDEV_TX_OK;
 569 }
 570
 571 static void ipip_tunnel_bind_dev(struct net_device *dev)
 572 {
 573         struct net_device *tdev = NULL;
 574         struct ip_tunnel *tunnel;
 575         struct iphdr *iph;
 576
 577         tunnel = netdev_priv(dev);
 578         iph = &tunnel->parms.iph;
 579
 580         if (iph->daddr) {
 581                 struct rtable *rt = ip_route_output_ports(dev_net(dev), NULL,
 582                                                           iph->daddr, iph->saddr,
 583                                                           0, 0,
 584                                                           IPPROTO_IPIP,
 585                                                           RT_TOS(iph->tos),
 586                                                           tunnel->parms.link);
 587
 588                 if (!IS_ERR(rt)) {
 589                         tdev = rt->dst.dev;
 590                         ip_rt_put(rt);
 591                 }
 592                 dev->flags |= IFF_POINTOPOINT;
 593         }
 594
 595         if (!tdev && tunnel->parms.link)
 596                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 597
 598         if (tdev) {
 599                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 600                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 601         }
 602         dev->iflink = tunnel->parms.link;
 603 }
 604
 605 static int
 606 ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 607 {
 608         int err = 0;
 609         struct ip_tunnel_parm p;
 610         struct ip_tunnel *t;
 611         struct net *net = dev_net(dev);
 612         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 613
 614         switch (cmd) {
 615         case SIOCGETTUNNEL:
 616                 t = NULL;
 617                 if (dev == ipn->fb_tunnel_dev) {
 618                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 619                                 err = -EFAULT;
 620                                 break;
 621                         }
 622                         t = ipip_tunnel_locate(net, &p, 0);
 623                 }
 624                 if (t == NULL)
 625                         t = netdev_priv(dev);
 626                 memcpy(&p, &t->parms, sizeof(p));
 627                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 628                         err = -EFAULT;
 629                 break;
 630
 631         case SIOCADDTUNNEL:
 632         case SIOCCHGTUNNEL:
 633                 err = -EPERM;
 634                 if (!capable(CAP_NET_ADMIN))
 635                         goto done;
 636
 637                 err = -EFAULT;
 638                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 639                         goto done;
 640
 641                 err = -EINVAL;
 642                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 643                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 644                         goto done;
 645                 if (p.iph.ttl)
 646                         p.iph.frag_off |= htons(IP_DF);
 647
 648                 t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 649
 650                 if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 651                         if (t != NULL) {
 652                                 if (t->dev != dev) {
 653                                         err = -EEXIST;
 654                                         break;
 655                                 }
 656                         } else {
 657                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 658                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 659                                         err = -EINVAL;
 660                                         break;
 661                                 }
 662                                 t = netdev_priv(dev);
 663                                 ipip_tunnel_unlink(ipn, t);
 664                                 synchronize_net();
 665                                 t->parms.iph.saddr = p.iph.saddr;
 666                                 t->parms.iph.daddr = p.iph.daddr;
 667                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 668                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 669                                 ipip_tunnel_link(ipn, t);
 670                                 netdev_state_change(dev);
 671                         }
 672                 }
 673
 674                 if (t) {
 675                         err = 0;
 676                         if (cmd == SIOCCHGTUNNEL) {
 677                                 t->parms.iph.ttl = p.iph.ttl;
 678                                 t->parms.iph.tos = p.iph.tos;
 679                                 t->parms.iph.frag_off = p.iph.frag_off;
 680                                 if (t->parms.link != p.link) {
 681                                         t->parms.link = p.link;
 682                                         ipip_tunnel_bind_dev(dev);
 683                                         netdev_state_change(dev);
 684                                 }
 685                         }
 686                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 687                                 err = -EFAULT;
 688                 } else
 689                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 690                 break;
 691
 692         case SIOCDELTUNNEL:
 693                 err = -EPERM;
 694                 if (!capable(CAP_NET_ADMIN))
 695                         goto done;
 696
 697                 if (dev == ipn->fb_tunnel_dev) {
 698                         err = -EFAULT;
 699                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 700                                 goto done;
 701                         err = -ENOENT;
 702                         if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
 703                                 goto done;
 704                         err = -EPERM;
 705                         if (t->dev == ipn->fb_tunnel_dev)
 706                                 goto done;
 707                         dev = t->dev;
 708                 }
 709                 unregister_netdevice(dev);
 710                 err = 0;
 711                 break;
 712
 713         default:
 714                 err = -EINVAL;
 715         }
 716
 717 done:
 718         return err;
 719 }
 720
 721 static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 722 {
 723         if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 724                 return -EINVAL;
 725         dev->mtu = new_mtu;
 726         return 0;
 727 }
 728
 729 static const struct net_device_ops ipip_netdev_ops = {
 730         .ndo_uninit     = ipip_tunnel_uninit,
 731         .ndo_start_xmit = ipip_tunnel_xmit,
 732         .ndo_do_ioctl   = ipip_tunnel_ioctl,
 733         .ndo_change_mtu = ipip_tunnel_change_mtu,
 734         .ndo_get_stats  = ipip_get_stats,
 735 };
 736
 737 static void ipip_dev_free(struct net_device *dev)
 738 {
 739         free_percpu(dev->tstats);
 740         free_netdev(dev);
 741 }
 742
 743 static void ipip_tunnel_setup(struct net_device *dev)
 744 {
 745         dev->netdev_ops         = &ipip_netdev_ops;
 746         dev->destructor         = ipip_dev_free;
 747
 748         dev->type               = ARPHRD_TUNNEL;
 749         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 750         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 751         dev->flags              = IFF_NOARP;
 752         dev->iflink             = 0;
 753         dev->addr_len           = 4;
 754         dev->features           |= NETIF_F_NETNS_LOCAL;
 755         dev->features           |= NETIF_F_LLTX;
 756         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 757 }
 758
 759 static int ipip_tunnel_init(struct net_device *dev)
 760 {
 761         struct ip_tunnel *tunnel = netdev_priv(dev);
 762
 763         tunnel->dev = dev;
 764         strcpy(tunnel->parms.name, dev->name);
 765
 766         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 767         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 768
 769         ipip_tunnel_bind_dev(dev);
 770
 771         dev->tstats = alloc_percpu(struct pcpu_tstats);
 772         if (!dev->tstats)
 773                 return -ENOMEM;
 774
 775         return 0;
 776 }
 777
 778 static int __net_init ipip_fb_tunnel_init(struct net_device *dev)
 779 {
 780         struct ip_tunnel *tunnel = netdev_priv(dev);
 781         struct iphdr *iph = &tunnel->parms.iph;
 782         struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
 783
 784         tunnel->dev = dev;
 785         strcpy(tunnel->parms.name, dev->name);
 786
 787         iph->version            = 4;
 788         iph->protocol           = IPPROTO_IPIP;
 789         iph->ihl                = 5;
 790
 791         dev->tstats = alloc_percpu(struct pcpu_tstats);
 792         if (!dev->tstats)
 793                 return -ENOMEM;
 794
 795         dev_hold(dev);
 796         rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
 797         return 0;
 798 }
 799
 800 static struct xfrm_tunnel ipip_handler __read_mostly = {
 801         .handler        =       ipip_rcv,
 802         .err_handler    =       ipip_err,
 803         .priority       =       1,
 804 };
 805
 806 static const char banner[] __initconst =
 807         KERN_INFO "IPv4 over IPv4 tunneling driver\n";
 808
 809 static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
 810 {
 811         int prio;
 812
 813         for (prio = 1; prio < 4; prio++) {
 814                 int h;
 815                 for (h = 0; h < HASH_SIZE; h++) {
 816                         struct ip_tunnel *t;
 817
 818                         t = rtnl_dereference(ipn->tunnels[prio][h]);
 819                         while (t != NULL) {
 820                                 unregister_netdevice_queue(t->dev, head);
 821                                 t = rtnl_dereference(t->next);
 822                         }
 823                 }
 824         }
 825 }
 826
 827 static int __net_init ipip_init_net(struct net *net)
 828 {
 829         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 830         int err;
 831
 832         ipn->tunnels[0] = ipn->tunnels_wc;
 833         ipn->tunnels[1] = ipn->tunnels_l;
 834         ipn->tunnels[2] = ipn->tunnels_r;
 835         ipn->tunnels[3] = ipn->tunnels_r_l;
 836
 837         ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
 838                                            "tunl0",
 839                                            ipip_tunnel_setup);
 840         if (!ipn->fb_tunnel_dev) {
 841                 err = -ENOMEM;
 842                 goto err_alloc_dev;
 843         }
 844         dev_net_set(ipn->fb_tunnel_dev, net);
 845
 846         err = ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
 847         if (err)
 848                 goto err_reg_dev;
 849
 850         if ((err = register_netdev(ipn->fb_tunnel_dev)))
 851                 goto err_reg_dev;
 852
 853         return 0;
 854
 855 err_reg_dev:
 856         ipip_dev_free(ipn->fb_tunnel_dev);
 857 err_alloc_dev:
 858         /* nothing */
 859         return err;
 860 }
 861
 862 static void __net_exit ipip_exit_net(struct net *net)
 863 {
 864         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 865         LIST_HEAD(list);
 866
 867         rtnl_lock();
 868         ipip_destroy_tunnels(ipn, &list);
 869         unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
 870         unregister_netdevice_many(&list);
 871         rtnl_unlock();
 872 }
 873
 874 static struct pernet_operations ipip_net_ops = {
 875         .init = ipip_init_net,
 876         .exit = ipip_exit_net,
 877         .id   = &ipip_net_id,
 878         .size = sizeof(struct ipip_net),
 879 };
 880
 881 static int __init ipip_init(void)
 882 {
 883         int err;
 884
 885         printk(banner);
 886
 887         err = register_pernet_device(&ipip_net_ops);
 888         if (err < 0)
 889                 return err;
 890         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
 891         if (err < 0) {
 892                 unregister_pernet_device(&ipip_net_ops);
 893                 printk(KERN_INFO "ipip init: can't register tunnel\n");
 894         }
 895         return err;
 896 }
 897
 898 static void __exit ipip_fini(void)
 899 {
 900         if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
 901                 printk(KERN_INFO "ipip close: can't deregister tunnel\n");
 902
 903         unregister_pernet_device(&ipip_net_ops);
 904 }
 905
 906 module_init(ipip_init);
 907 module_exit(ipip_fini);
 908 MODULE_LICENSE("GPL");
 909 MODULE_ALIAS_NETDEV("tunl0");