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                         .fl4_dst = dst,
 467                         .fl4_src= tiph->saddr,
 468                         .fl4_tos = RT_TOS(tos),
 469                         .proto = IPPROTO_IPIP
 470                 };
 471
 472                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
 473                         dev->stats.tx_carrier_errors++;
 474                         goto tx_error_icmp;
 475                 }
 476         }
 477         tdev = rt->dst.dev;
 478
 479         if (tdev == dev) {
 480                 ip_rt_put(rt);
 481                 dev->stats.collisions++;
 482                 goto tx_error;
 483         }
 484
 485         df |= old_iph->frag_off & htons(IP_DF);
 486
 487         if (df) {
 488                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
 489
 490                 if (mtu < 68) {
 491                         dev->stats.collisions++;
 492                         ip_rt_put(rt);
 493                         goto tx_error;
 494                 }
 495
 496                 if (skb_dst(skb))
 497                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 498
 499                 if ((old_iph->frag_off & htons(IP_DF)) &&
 500                     mtu < ntohs(old_iph->tot_len)) {
 501                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
 502                                   htonl(mtu));
 503                         ip_rt_put(rt);
 504                         goto tx_error;
 505                 }
 506         }
 507
 508         if (tunnel->err_count > 0) {
 509                 if (time_before(jiffies,
 510                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 511                         tunnel->err_count--;
 512                         dst_link_failure(skb);
 513                 } else
 514                         tunnel->err_count = 0;
 515         }
 516
 517         /*
 518          * Okay, now see if we can stuff it in the buffer as-is.
 519          */
 520         max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
 521
 522         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
 523             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 524                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 525                 if (!new_skb) {
 526                         ip_rt_put(rt);
 527                         dev->stats.tx_dropped++;
 528                         dev_kfree_skb(skb);
 529                         return NETDEV_TX_OK;
 530                 }
 531                 if (skb->sk)
 532                         skb_set_owner_w(new_skb, skb->sk);
 533                 dev_kfree_skb(skb);
 534                 skb = new_skb;
 535                 old_iph = ip_hdr(skb);
 536         }
 537
 538         skb->transport_header = skb->network_header;
 539         skb_push(skb, sizeof(struct iphdr));
 540         skb_reset_network_header(skb);
 541         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 542         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 543                               IPSKB_REROUTED);
 544         skb_dst_drop(skb);
 545         skb_dst_set(skb, &rt->dst);
 546
 547         /*
 548          *      Push down and install the IPIP header.
 549          */
 550
 551         iph                     =       ip_hdr(skb);
 552         iph->version            =       4;
 553         iph->ihl                =       sizeof(struct iphdr)>>2;
 554         iph->frag_off           =       df;
 555         iph->protocol           =       IPPROTO_IPIP;
 556         iph->tos                =       INET_ECN_encapsulate(tos, old_iph->tos);
 557         iph->daddr              =       rt->rt_dst;
 558         iph->saddr              =       rt->rt_src;
 559
 560         if ((iph->ttl = tiph->ttl) == 0)
 561                 iph->ttl        =       old_iph->ttl;
 562
 563         nf_reset(skb);
 564         tstats = this_cpu_ptr(dev->tstats);
 565         __IPTUNNEL_XMIT(tstats, &dev->stats);
 566         return NETDEV_TX_OK;
 567
 568 tx_error_icmp:
 569         dst_link_failure(skb);
 570 tx_error:
 571         dev->stats.tx_errors++;
 572         dev_kfree_skb(skb);
 573         return NETDEV_TX_OK;
 574 }
 575
 576 static void ipip_tunnel_bind_dev(struct net_device *dev)
 577 {
 578         struct net_device *tdev = NULL;
 579         struct ip_tunnel *tunnel;
 580         struct iphdr *iph;
 581
 582         tunnel = netdev_priv(dev);
 583         iph = &tunnel->parms.iph;
 584
 585         if (iph->daddr) {
 586                 struct flowi fl = {
 587                         .oif = tunnel->parms.link,
 588                         .fl4_dst = iph->daddr,
 589                         .fl4_src = iph->saddr,
 590                         .fl4_tos = RT_TOS(iph->tos),
 591                         .proto = IPPROTO_IPIP
 592                 };
 593                 struct rtable *rt;
 594
 595                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
 596                         tdev = rt->dst.dev;
 597                         ip_rt_put(rt);
 598                 }
 599                 dev->flags |= IFF_POINTOPOINT;
 600         }
 601
 602         if (!tdev && tunnel->parms.link)
 603                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 604
 605         if (tdev) {
 606                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
 607                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
 608         }
 609         dev->iflink = tunnel->parms.link;
 610 }
 611
 612 static int
 613 ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 614 {
 615         int err = 0;
 616         struct ip_tunnel_parm p;
 617         struct ip_tunnel *t;
 618         struct net *net = dev_net(dev);
 619         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 620
 621         switch (cmd) {
 622         case SIOCGETTUNNEL:
 623                 t = NULL;
 624                 if (dev == ipn->fb_tunnel_dev) {
 625                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 626                                 err = -EFAULT;
 627                                 break;
 628                         }
 629                         t = ipip_tunnel_locate(net, &p, 0);
 630                 }
 631                 if (t == NULL)
 632                         t = netdev_priv(dev);
 633                 memcpy(&p, &t->parms, sizeof(p));
 634                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 635                         err = -EFAULT;
 636                 break;
 637
 638         case SIOCADDTUNNEL:
 639         case SIOCCHGTUNNEL:
 640                 err = -EPERM;
 641                 if (!capable(CAP_NET_ADMIN))
 642                         goto done;
 643
 644                 err = -EFAULT;
 645                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 646                         goto done;
 647
 648                 err = -EINVAL;
 649                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 650                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
 651                         goto done;
 652                 if (p.iph.ttl)
 653                         p.iph.frag_off |= htons(IP_DF);
 654
 655                 t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
 656
 657                 if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 658                         if (t != NULL) {
 659                                 if (t->dev != dev) {
 660                                         err = -EEXIST;
 661                                         break;
 662                                 }
 663                         } else {
 664                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
 665                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
 666                                         err = -EINVAL;
 667                                         break;
 668                                 }
 669                                 t = netdev_priv(dev);
 670                                 ipip_tunnel_unlink(ipn, t);
 671                                 synchronize_net();
 672                                 t->parms.iph.saddr = p.iph.saddr;
 673                                 t->parms.iph.daddr = p.iph.daddr;
 674                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
 675                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
 676                                 ipip_tunnel_link(ipn, t);
 677                                 netdev_state_change(dev);
 678                         }
 679                 }
 680
 681                 if (t) {
 682                         err = 0;
 683                         if (cmd == SIOCCHGTUNNEL) {
 684                                 t->parms.iph.ttl = p.iph.ttl;
 685                                 t->parms.iph.tos = p.iph.tos;
 686                                 t->parms.iph.frag_off = p.iph.frag_off;
 687                                 if (t->parms.link != p.link) {
 688                                         t->parms.link = p.link;
 689                                         ipip_tunnel_bind_dev(dev);
 690                                         netdev_state_change(dev);
 691                                 }
 692                         }
 693                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
 694                                 err = -EFAULT;
 695                 } else
 696                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
 697                 break;
 698
 699         case SIOCDELTUNNEL:
 700                 err = -EPERM;
 701                 if (!capable(CAP_NET_ADMIN))
 702                         goto done;
 703
 704                 if (dev == ipn->fb_tunnel_dev) {
 705                         err = -EFAULT;
 706                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 707                                 goto done;
 708                         err = -ENOENT;
 709                         if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
 710                                 goto done;
 711                         err = -EPERM;
 712                         if (t->dev == ipn->fb_tunnel_dev)
 713                                 goto done;
 714                         dev = t->dev;
 715                 }
 716                 unregister_netdevice(dev);
 717                 err = 0;
 718                 break;
 719
 720         default:
 721                 err = -EINVAL;
 722         }
 723
 724 done:
 725         return err;
 726 }
 727
 728 static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 729 {
 730         if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
 731                 return -EINVAL;
 732         dev->mtu = new_mtu;
 733         return 0;
 734 }
 735
 736 static const struct net_device_ops ipip_netdev_ops = {
 737         .ndo_uninit     = ipip_tunnel_uninit,
 738         .ndo_start_xmit = ipip_tunnel_xmit,
 739         .ndo_do_ioctl   = ipip_tunnel_ioctl,
 740         .ndo_change_mtu = ipip_tunnel_change_mtu,
 741         .ndo_get_stats  = ipip_get_stats,
 742 };
 743
 744 static void ipip_dev_free(struct net_device *dev)
 745 {
 746         free_percpu(dev->tstats);
 747         free_netdev(dev);
 748 }
 749
 750 static void ipip_tunnel_setup(struct net_device *dev)
 751 {
 752         dev->netdev_ops         = &ipip_netdev_ops;
 753         dev->destructor         = ipip_dev_free;
 754
 755         dev->type               = ARPHRD_TUNNEL;
 756         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 757         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
 758         dev->flags              = IFF_NOARP;
 759         dev->iflink             = 0;
 760         dev->addr_len           = 4;
 761         dev->features           |= NETIF_F_NETNS_LOCAL;
 762         dev->features           |= NETIF_F_LLTX;
 763         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 764 }
 765
 766 static int ipip_tunnel_init(struct net_device *dev)
 767 {
 768         struct ip_tunnel *tunnel = netdev_priv(dev);
 769
 770         tunnel->dev = dev;
 771         strcpy(tunnel->parms.name, dev->name);
 772
 773         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
 774         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
 775
 776         ipip_tunnel_bind_dev(dev);
 777
 778         dev->tstats = alloc_percpu(struct pcpu_tstats);
 779         if (!dev->tstats)
 780                 return -ENOMEM;
 781
 782         return 0;
 783 }
 784
 785 static int __net_init ipip_fb_tunnel_init(struct net_device *dev)
 786 {
 787         struct ip_tunnel *tunnel = netdev_priv(dev);
 788         struct iphdr *iph = &tunnel->parms.iph;
 789         struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
 790
 791         tunnel->dev = dev;
 792         strcpy(tunnel->parms.name, dev->name);
 793
 794         iph->version            = 4;
 795         iph->protocol           = IPPROTO_IPIP;
 796         iph->ihl                = 5;
 797
 798         dev->tstats = alloc_percpu(struct pcpu_tstats);
 799         if (!dev->tstats)
 800                 return -ENOMEM;
 801
 802         dev_hold(dev);
 803         rcu_assign_pointer(ipn->tunnels_wc[0], tunnel);
 804         return 0;
 805 }
 806
 807 static struct xfrm_tunnel ipip_handler __read_mostly = {
 808         .handler        =       ipip_rcv,
 809         .err_handler    =       ipip_err,
 810         .priority       =       1,
 811 };
 812
 813 static const char banner[] __initconst =
 814         KERN_INFO "IPv4 over IPv4 tunneling driver\n";
 815
 816 static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
 817 {
 818         int prio;
 819
 820         for (prio = 1; prio < 4; prio++) {
 821                 int h;
 822                 for (h = 0; h < HASH_SIZE; h++) {
 823                         struct ip_tunnel *t;
 824
 825                         t = rtnl_dereference(ipn->tunnels[prio][h]);
 826                         while (t != NULL) {
 827                                 unregister_netdevice_queue(t->dev, head);
 828                                 t = rtnl_dereference(t->next);
 829                         }
 830                 }
 831         }
 832 }
 833
 834 static int __net_init ipip_init_net(struct net *net)
 835 {
 836         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 837         int err;
 838
 839         ipn->tunnels[0] = ipn->tunnels_wc;
 840         ipn->tunnels[1] = ipn->tunnels_l;
 841         ipn->tunnels[2] = ipn->tunnels_r;
 842         ipn->tunnels[3] = ipn->tunnels_r_l;
 843
 844         ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
 845                                            "tunl0",
 846                                            ipip_tunnel_setup);
 847         if (!ipn->fb_tunnel_dev) {
 848                 err = -ENOMEM;
 849                 goto err_alloc_dev;
 850         }
 851         dev_net_set(ipn->fb_tunnel_dev, net);
 852
 853         err = ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
 854         if (err)
 855                 goto err_reg_dev;
 856
 857         if ((err = register_netdev(ipn->fb_tunnel_dev)))
 858                 goto err_reg_dev;
 859
 860         return 0;
 861
 862 err_reg_dev:
 863         ipip_dev_free(ipn->fb_tunnel_dev);
 864 err_alloc_dev:
 865         /* nothing */
 866         return err;
 867 }
 868
 869 static void __net_exit ipip_exit_net(struct net *net)
 870 {
 871         struct ipip_net *ipn = net_generic(net, ipip_net_id);
 872         LIST_HEAD(list);
 873
 874         rtnl_lock();
 875         ipip_destroy_tunnels(ipn, &list);
 876         unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
 877         unregister_netdevice_many(&list);
 878         rtnl_unlock();
 879 }
 880
 881 static struct pernet_operations ipip_net_ops = {
 882         .init = ipip_init_net,
 883         .exit = ipip_exit_net,
 884         .id   = &ipip_net_id,
 885         .size = sizeof(struct ipip_net),
 886 };
 887
 888 static int __init ipip_init(void)
 889 {
 890         int err;
 891
 892         printk(banner);
 893
 894         err = register_pernet_device(&ipip_net_ops);
 895         if (err < 0)
 896                 return err;
 897         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
 898         if (err < 0) {
 899                 unregister_pernet_device(&ipip_net_ops);
 900                 printk(KERN_INFO "ipip init: can't register tunnel\n");
 901         }
 902         return err;
 903 }
 904
 905 static void __exit ipip_fini(void)
 906 {
 907         if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
 908                 printk(KERN_INFO "ipip close: can't deregister tunnel\n");
 909
 910         unregister_pernet_device(&ipip_net_ops);
 911 }
 912
 913 module_init(ipip_init);
 914 module_exit(ipip_fini);
 915 MODULE_LICENSE("GPL");