net/ipv4/ip_gre.c

   1 /*
   2  *      Linux NET3:     GRE over IP protocol decoder.
   3  *
   4  *      Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru)
   5  *
   6  *      This program is free software; you can redistribute it and/or
   7  *      modify it under the terms of the GNU General Public License
   8  *      as published by the Free Software Foundation; either version
   9  *      2 of the License, or (at your option) any later version.
  10  *
  11  */
  12
  13 #include <linux/capability.h>
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/slab.h>
  18 #include <asm/uaccess.h>
  19 #include <linux/skbuff.h>
  20 #include <linux/netdevice.h>
  21 #include <linux/in.h>
  22 #include <linux/tcp.h>
  23 #include <linux/udp.h>
  24 #include <linux/if_arp.h>
  25 #include <linux/mroute.h>
  26 #include <linux/init.h>
  27 #include <linux/in6.h>
  28 #include <linux/inetdevice.h>
  29 #include <linux/igmp.h>
  30 #include <linux/netfilter_ipv4.h>
  31 #include <linux/etherdevice.h>
  32 #include <linux/if_ether.h>
  33
  34 #include <net/sock.h>
  35 #include <net/ip.h>
  36 #include <net/icmp.h>
  37 #include <net/protocol.h>
  38 #include <net/ipip.h>
  39 #include <net/arp.h>
  40 #include <net/checksum.h>
  41 #include <net/dsfield.h>
  42 #include <net/inet_ecn.h>
  43 #include <net/xfrm.h>
  44 #include <net/net_namespace.h>
  45 #include <net/netns/generic.h>
  46 #include <net/rtnetlink.h>
  47 #include <net/gre.h>
  48
  49 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
  50 #include <net/ipv6.h>
  51 #include <net/ip6_fib.h>
  52 #include <net/ip6_route.h>
  53 #endif
  54
  55 /*
  56    Problems & solutions
  57    --------------------
  58
  59    1. The most important issue is detecting local dead loops.
  60    They would cause complete host lockup in transmit, which
  61    would be "resolved" by stack overflow or, if queueing is enabled,
  62    with infinite looping in net_bh.
  63
  64    We cannot track such dead loops during route installation,
  65    it is infeasible task. The most general solutions would be
  66    to keep skb->encapsulation counter (sort of local ttl),
  67    and silently drop packet when it expires. It is a good
  68    solution, but it supposes maintaing new variable in ALL
  69    skb, even if no tunneling is used.
  70
  71    Current solution: xmit_recursion breaks dead loops. This is a percpu
  72    counter, since when we enter the first ndo_xmit(), cpu migration is
  73    forbidden. We force an exit if this counter reaches RECURSION_LIMIT
  74
  75    2. Networking dead loops would not kill routers, but would really
  76    kill network. IP hop limit plays role of "t->recursion" in this case,
  77    if we copy it from packet being encapsulated to upper header.
  78    It is very good solution, but it introduces two problems:
  79
  80    - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
  81      do not work over tunnels.
  82    - traceroute does not work. I planned to relay ICMP from tunnel,
  83      so that this problem would be solved and traceroute output
  84      would even more informative. This idea appeared to be wrong:
  85      only Linux complies to rfc1812 now (yes, guys, Linux is the only
  86      true router now :-)), all routers (at least, in neighbourhood of mine)
  87      return only 8 bytes of payload. It is the end.
  88
  89    Hence, if we want that OSPF worked or traceroute said something reasonable,
  90    we should search for another solution.
  91
  92    One of them is to parse packet trying to detect inner encapsulation
  93    made by our node. It is difficult or even impossible, especially,
  94    taking into account fragmentation. TO be short, tt is not solution at all.
  95
  96    Current solution: The solution was UNEXPECTEDLY SIMPLE.
  97    We force DF flag on tunnels with preconfigured hop limit,
  98    that is ALL. :-) Well, it does not remove the problem completely,
  99    but exponential growth of network traffic is changed to linear
 100    (branches, that exceed pmtu are pruned) and tunnel mtu
 101    fastly degrades to value <68, where looping stops.
 102    Yes, it is not good if there exists a router in the loop,
 103    which does not force DF, even when encapsulating packets have DF set.
 104    But it is not our problem! Nobody could accuse us, we made
 105    all that we could make. Even if it is your gated who injected
 106    fatal route to network, even if it were you who configured
 107    fatal static route: you are innocent. :-)
 108
 109
 110
 111    3. Really, ipv4/ipip.c, ipv4/ip_gre.c and ipv6/sit.c contain
 112    practically identical code. It would be good to glue them
 113    together, but it is not very evident, how to make them modular.
 114    sit is integral part of IPv6, ipip and gre are naturally modular.
 115    We could extract common parts (hash table, ioctl etc)
 116    to a separate module (ip_tunnel.c).
 117
 118    Alexey Kuznetsov.
 119  */
 120
 121 static struct rtnl_link_ops ipgre_link_ops __read_mostly;
 122 static int ipgre_tunnel_init(struct net_device *dev);
 123 static void ipgre_tunnel_setup(struct net_device *dev);
 124 static int ipgre_tunnel_bind_dev(struct net_device *dev);
 125
 126 /* Fallback tunnel: no source, no destination, no key, no options */
 127
 128 #define HASH_SIZE  16
 129
 130 static int ipgre_net_id __read_mostly;
 131 struct ipgre_net {
 132         struct ip_tunnel __rcu *tunnels[4][HASH_SIZE];
 133
 134         struct net_device *fb_tunnel_dev;
 135 };
 136
 137 /* Tunnel hash table */
 138
 139 /*
 140    4 hash tables:
 141
 142    3: (remote,local)
 143    2: (remote,*)
 144    1: (*,local)
 145    0: (*,*)
 146
 147    We require exact key match i.e. if a key is present in packet
 148    it will match only tunnel with the same key; if it is not present,
 149    it will match only keyless tunnel.
 150
 151    All keysless packets, if not matched configured keyless tunnels
 152    will match fallback tunnel.
 153  */
 154
 155 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 156
 157 #define tunnels_r_l     tunnels[3]
 158 #define tunnels_r       tunnels[2]
 159 #define tunnels_l       tunnels[1]
 160 #define tunnels_wc      tunnels[0]
 161 /*
 162  * Locking : hash tables are protected by RCU and RTNL
 163  */
 164
 165 #define for_each_ip_tunnel_rcu(start) \
 166         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 167
 168 /* often modified stats are per cpu, other are shared (netdev->stats) */
 169 struct pcpu_tstats {
 170         unsigned long   rx_packets;
 171         unsigned long   rx_bytes;
 172         unsigned long   tx_packets;
 173         unsigned long   tx_bytes;
 174 };
 175
 176 static struct net_device_stats *ipgre_get_stats(struct net_device *dev)
 177 {
 178         struct pcpu_tstats sum = { 0 };
 179         int i;
 180
 181         for_each_possible_cpu(i) {
 182                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 183
 184                 sum.rx_packets += tstats->rx_packets;
 185                 sum.rx_bytes   += tstats->rx_bytes;
 186                 sum.tx_packets += tstats->tx_packets;
 187                 sum.tx_bytes   += tstats->tx_bytes;
 188         }
 189         dev->stats.rx_packets = sum.rx_packets;
 190         dev->stats.rx_bytes   = sum.rx_bytes;
 191         dev->stats.tx_packets = sum.tx_packets;
 192         dev->stats.tx_bytes   = sum.tx_bytes;
 193         return &dev->stats;
 194 }
 195
 196 /* Given src, dst and key, find appropriate for input tunnel. */
 197
 198 static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev,
 199                                               __be32 remote, __be32 local,
 200                                               __be32 key, __be16 gre_proto)
 201 {
 202         struct net *net = dev_net(dev);
 203         int link = dev->ifindex;
 204         unsigned int h0 = HASH(remote);
 205         unsigned int h1 = HASH(key);
 206         struct ip_tunnel *t, *cand = NULL;
 207         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 208         int dev_type = (gre_proto == htons(ETH_P_TEB)) ?
 209                        ARPHRD_ETHER : ARPHRD_IPGRE;
 210         int score, cand_score = 4;
 211
 212         for_each_ip_tunnel_rcu(ign->tunnels_r_l[h0 ^ h1]) {
 213                 if (local != t->parms.iph.saddr ||
 214                     remote != t->parms.iph.daddr ||
 215                     key != t->parms.i_key ||
 216                     !(t->dev->flags & IFF_UP))
 217                         continue;
 218
 219                 if (t->dev->type != ARPHRD_IPGRE &&
 220                     t->dev->type != dev_type)
 221                         continue;
 222
 223                 score = 0;
 224                 if (t->parms.link != link)
 225                         score |= 1;
 226                 if (t->dev->type != dev_type)
 227                         score |= 2;
 228                 if (score == 0)
 229                         return t;
 230
 231                 if (score < cand_score) {
 232                         cand = t;
 233                         cand_score = score;
 234                 }
 235         }
 236
 237         for_each_ip_tunnel_rcu(ign->tunnels_r[h0 ^ h1]) {
 238                 if (remote != t->parms.iph.daddr ||
 239                     key != t->parms.i_key ||
 240                     !(t->dev->flags & IFF_UP))
 241                         continue;
 242
 243                 if (t->dev->type != ARPHRD_IPGRE &&
 244                     t->dev->type != dev_type)
 245                         continue;
 246
 247                 score = 0;
 248                 if (t->parms.link != link)
 249                         score |= 1;
 250                 if (t->dev->type != dev_type)
 251                         score |= 2;
 252                 if (score == 0)
 253                         return t;
 254
 255                 if (score < cand_score) {
 256                         cand = t;
 257                         cand_score = score;
 258                 }
 259         }
 260
 261         for_each_ip_tunnel_rcu(ign->tunnels_l[h1]) {
 262                 if ((local != t->parms.iph.saddr &&
 263                      (local != t->parms.iph.daddr ||
 264                       !ipv4_is_multicast(local))) ||
 265                     key != t->parms.i_key ||
 266                     !(t->dev->flags & IFF_UP))
 267                         continue;
 268
 269                 if (t->dev->type != ARPHRD_IPGRE &&
 270                     t->dev->type != dev_type)
 271                         continue;
 272
 273                 score = 0;
 274                 if (t->parms.link != link)
 275                         score |= 1;
 276                 if (t->dev->type != dev_type)
 277                         score |= 2;
 278                 if (score == 0)
 279                         return t;
 280
 281                 if (score < cand_score) {
 282                         cand = t;
 283                         cand_score = score;
 284                 }
 285         }
 286
 287         for_each_ip_tunnel_rcu(ign->tunnels_wc[h1]) {
 288                 if (t->parms.i_key != key ||
 289                     !(t->dev->flags & IFF_UP))
 290                         continue;
 291
 292                 if (t->dev->type != ARPHRD_IPGRE &&
 293                     t->dev->type != dev_type)
 294                         continue;
 295
 296                 score = 0;
 297                 if (t->parms.link != link)
 298                         score |= 1;
 299                 if (t->dev->type != dev_type)
 300                         score |= 2;
 301                 if (score == 0)
 302                         return t;
 303
 304                 if (score < cand_score) {
 305                         cand = t;
 306                         cand_score = score;
 307                 }
 308         }
 309
 310         if (cand != NULL)
 311                 return cand;
 312
 313         dev = ign->fb_tunnel_dev;
 314         if (dev->flags & IFF_UP)
 315                 return netdev_priv(dev);
 316
 317         return NULL;
 318 }
 319
 320 static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign,
 321                 struct ip_tunnel_parm *parms)
 322 {
 323         __be32 remote = parms->iph.daddr;
 324         __be32 local = parms->iph.saddr;
 325         __be32 key = parms->i_key;
 326         unsigned int h = HASH(key);
 327         int prio = 0;
 328
 329         if (local)
 330                 prio |= 1;
 331         if (remote && !ipv4_is_multicast(remote)) {
 332                 prio |= 2;
 333                 h ^= HASH(remote);
 334         }
 335
 336         return &ign->tunnels[prio][h];
 337 }
 338
 339 static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign,
 340                 struct ip_tunnel *t)
 341 {
 342         return __ipgre_bucket(ign, &t->parms);
 343 }
 344
 345 static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t)
 346 {
 347         struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t);
 348
 349         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
 350         rcu_assign_pointer(*tp, t);
 351 }
 352
 353 static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t)
 354 {
 355         struct ip_tunnel __rcu **tp;
 356         struct ip_tunnel *iter;
 357
 358         for (tp = ipgre_bucket(ign, t);
 359              (iter = rtnl_dereference(*tp)) != NULL;
 360              tp = &iter->next) {
 361                 if (t == iter) {
 362                         rcu_assign_pointer(*tp, t->next);
 363                         break;
 364                 }
 365         }
 366 }
 367
 368 static struct ip_tunnel *ipgre_tunnel_find(struct net *net,
 369                                            struct ip_tunnel_parm *parms,
 370                                            int type)
 371 {
 372         __be32 remote = parms->iph.daddr;
 373         __be32 local = parms->iph.saddr;
 374         __be32 key = parms->i_key;
 375         int link = parms->link;
 376         struct ip_tunnel *t;
 377         struct ip_tunnel __rcu **tp;
 378         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 379
 380         for (tp = __ipgre_bucket(ign, parms);
 381              (t = rtnl_dereference(*tp)) != NULL;
 382              tp = &t->next)
 383                 if (local == t->parms.iph.saddr &&
 384                     remote == t->parms.iph.daddr &&
 385                     key == t->parms.i_key &&
 386                     link == t->parms.link &&
 387                     type == t->dev->type)
 388                         break;
 389
 390         return t;
 391 }
 392
 393 static struct ip_tunnel *ipgre_tunnel_locate(struct net *net,
 394                 struct ip_tunnel_parm *parms, int create)
 395 {
 396         struct ip_tunnel *t, *nt;
 397         struct net_device *dev;
 398         char name[IFNAMSIZ];
 399         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 400
 401         t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE);
 402         if (t || !create)
 403                 return t;
 404
 405         if (parms->name[0])
 406                 strlcpy(name, parms->name, IFNAMSIZ);
 407         else
 408                 strcpy(name, "gre%d");
 409
 410         dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup);
 411         if (!dev)
 412                 return NULL;
 413
 414         dev_net_set(dev, net);
 415
 416         nt = netdev_priv(dev);
 417         nt->parms = *parms;
 418         dev->rtnl_link_ops = &ipgre_link_ops;
 419
 420         dev->mtu = ipgre_tunnel_bind_dev(dev);
 421
 422         if (register_netdevice(dev) < 0)
 423                 goto failed_free;
 424
 425         dev_hold(dev);
 426         ipgre_tunnel_link(ign, nt);
 427         return nt;
 428
 429 failed_free:
 430         free_netdev(dev);
 431         return NULL;
 432 }
 433
 434 static void ipgre_tunnel_uninit(struct net_device *dev)
 435 {
 436         struct net *net = dev_net(dev);
 437         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 438
 439         ipgre_tunnel_unlink(ign, netdev_priv(dev));
 440         dev_put(dev);
 441 }
 442
 443
 444 static void ipgre_err(struct sk_buff *skb, u32 info)
 445 {
 446
 447 /* All the routers (except for Linux) return only
 448    8 bytes of packet payload. It means, that precise relaying of
 449    ICMP in the real Internet is absolutely infeasible.
 450
 451    Moreover, Cisco "wise men" put GRE key to the third word
 452    in GRE header. It makes impossible maintaining even soft state for keyed
 453    GRE tunnels with enabled checksum. Tell them "thank you".
 454
 455    Well, I wonder, rfc1812 was written by Cisco employee,
 456    what the hell these idiots break standrads established
 457    by themself???
 458  */
 459
 460         const struct iphdr *iph = (const struct iphdr *)skb->data;
 461         __be16       *p = (__be16*)(skb->data+(iph->ihl<<2));
 462         int grehlen = (iph->ihl<<2) + 4;
 463         const int type = icmp_hdr(skb)->type;
 464         const int code = icmp_hdr(skb)->code;
 465         struct ip_tunnel *t;
 466         __be16 flags;
 467
 468         flags = p[0];
 469         if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
 470                 if (flags&(GRE_VERSION|GRE_ROUTING))
 471                         return;
 472                 if (flags&GRE_KEY) {
 473                         grehlen += 4;
 474                         if (flags&GRE_CSUM)
 475                                 grehlen += 4;
 476                 }
 477         }
 478
 479         /* If only 8 bytes returned, keyed message will be dropped here */
 480         if (skb_headlen(skb) < grehlen)
 481                 return;
 482
 483         switch (type) {
 484         default:
 485         case ICMP_PARAMETERPROB:
 486                 return;
 487
 488         case ICMP_DEST_UNREACH:
 489                 switch (code) {
 490                 case ICMP_SR_FAILED:
 491                 case ICMP_PORT_UNREACH:
 492                         /* Impossible event. */
 493                         return;
 494                 case ICMP_FRAG_NEEDED:
 495                         /* Soft state for pmtu is maintained by IP core. */
 496                         return;
 497                 default:
 498                         /* All others are translated to HOST_UNREACH.
 499                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 500                            I believe they are just ether pollution. --ANK
 501                          */
 502                         break;
 503                 }
 504                 break;
 505         case ICMP_TIME_EXCEEDED:
 506                 if (code != ICMP_EXC_TTL)
 507                         return;
 508                 break;
 509         }
 510
 511         rcu_read_lock();
 512         t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr,
 513                                 flags & GRE_KEY ?
 514                                 *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
 515                                 p[1]);
 516         if (t == NULL || t->parms.iph.daddr == 0 ||
 517             ipv4_is_multicast(t->parms.iph.daddr))
 518                 goto out;
 519
 520         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 521                 goto out;
 522
 523         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 524                 t->err_count++;
 525         else
 526                 t->err_count = 1;
 527         t->err_time = jiffies;
 528 out:
 529         rcu_read_unlock();
 530 }
 531
 532 static inline void ipgre_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
 533 {
 534         if (INET_ECN_is_ce(iph->tos)) {
 535                 if (skb->protocol == htons(ETH_P_IP)) {
 536                         IP_ECN_set_ce(ip_hdr(skb));
 537                 } else if (skb->protocol == htons(ETH_P_IPV6)) {
 538                         IP6_ECN_set_ce(ipv6_hdr(skb));
 539                 }
 540         }
 541 }
 542
 543 static inline u8
 544 ipgre_ecn_encapsulate(u8 tos, const struct iphdr *old_iph, struct sk_buff *skb)
 545 {
 546         u8 inner = 0;
 547         if (skb->protocol == htons(ETH_P_IP))
 548                 inner = old_iph->tos;
 549         else if (skb->protocol == htons(ETH_P_IPV6))
 550                 inner = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
 551         return INET_ECN_encapsulate(tos, inner);
 552 }
 553
 554 static int ipgre_rcv(struct sk_buff *skb)
 555 {
 556         const struct iphdr *iph;
 557         u8     *h;
 558         __be16    flags;
 559         __sum16   csum = 0;
 560         __be32 key = 0;
 561         u32    seqno = 0;
 562         struct ip_tunnel *tunnel;
 563         int    offset = 4;
 564         __be16 gre_proto;
 565
 566         if (!pskb_may_pull(skb, 16))
 567                 goto drop_nolock;
 568
 569         iph = ip_hdr(skb);
 570         h = skb->data;
 571         flags = *(__be16*)h;
 572
 573         if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
 574                 /* - Version must be 0.
 575                    - We do not support routing headers.
 576                  */
 577                 if (flags&(GRE_VERSION|GRE_ROUTING))
 578                         goto drop_nolock;
 579
 580                 if (flags&GRE_CSUM) {
 581                         switch (skb->ip_summed) {
 582                         case CHECKSUM_COMPLETE:
 583                                 csum = csum_fold(skb->csum);
 584                                 if (!csum)
 585                                         break;
 586                                 /* fall through */
 587                         case CHECKSUM_NONE:
 588                                 skb->csum = 0;
 589                                 csum = __skb_checksum_complete(skb);
 590                                 skb->ip_summed = CHECKSUM_COMPLETE;
 591                         }
 592                         offset += 4;
 593                 }
 594                 if (flags&GRE_KEY) {
 595                         key = *(__be32*)(h + offset);
 596                         offset += 4;
 597                 }
 598                 if (flags&GRE_SEQ) {
 599                         seqno = ntohl(*(__be32*)(h + offset));
 600                         offset += 4;
 601                 }
 602         }
 603
 604         gre_proto = *(__be16 *)(h + 2);
 605
 606         rcu_read_lock();
 607         if ((tunnel = ipgre_tunnel_lookup(skb->dev,
 608                                           iph->saddr, iph->daddr, key,
 609                                           gre_proto))) {
 610                 struct pcpu_tstats *tstats;
 611
 612                 secpath_reset(skb);
 613
 614                 skb->protocol = gre_proto;
 615                 /* WCCP version 1 and 2 protocol decoding.
 616                  * - Change protocol to IP
 617                  * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
 618                  */
 619                 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
 620                         skb->protocol = htons(ETH_P_IP);
 621                         if ((*(h + offset) & 0xF0) != 0x40)
 622                                 offset += 4;
 623                 }
 624
 625                 skb->mac_header = skb->network_header;
 626                 __pskb_pull(skb, offset);
 627                 skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
 628                 skb->pkt_type = PACKET_HOST;
 629 #ifdef CONFIG_NET_IPGRE_BROADCAST
 630                 if (ipv4_is_multicast(iph->daddr)) {
 631                         /* Looped back packet, drop it! */
 632                         if (rt_is_output_route(skb_rtable(skb)))
 633                                 goto drop;
 634                         tunnel->dev->stats.multicast++;
 635                         skb->pkt_type = PACKET_BROADCAST;
 636                 }
 637 #endif
 638
 639                 if (((flags&GRE_CSUM) && csum) ||
 640                     (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
 641                         tunnel->dev->stats.rx_crc_errors++;
 642                         tunnel->dev->stats.rx_errors++;
 643                         goto drop;
 644                 }
 645                 if (tunnel->parms.i_flags&GRE_SEQ) {
 646                         if (!(flags&GRE_SEQ) ||
 647                             (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
 648                                 tunnel->dev->stats.rx_fifo_errors++;
 649                                 tunnel->dev->stats.rx_errors++;
 650                                 goto drop;
 651                         }
 652                         tunnel->i_seqno = seqno + 1;
 653                 }
 654
 655                 /* Warning: All skb pointers will be invalidated! */
 656                 if (tunnel->dev->type == ARPHRD_ETHER) {
 657                         if (!pskb_may_pull(skb, ETH_HLEN)) {
 658                                 tunnel->dev->stats.rx_length_errors++;
 659                                 tunnel->dev->stats.rx_errors++;
 660                                 goto drop;
 661                         }
 662
 663                         iph = ip_hdr(skb);
 664                         skb->protocol = eth_type_trans(skb, tunnel->dev);
 665                         skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
 666                 }
 667
 668                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 669                 tstats->rx_packets++;
 670                 tstats->rx_bytes += skb->len;
 671
 672                 __skb_tunnel_rx(skb, tunnel->dev);
 673
 674                 skb_reset_network_header(skb);
 675                 ipgre_ecn_decapsulate(iph, skb);
 676
 677                 netif_rx(skb);
 678
 679                 rcu_read_unlock();
 680                 return 0;
 681         }
 682         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 683
 684 drop:
 685         rcu_read_unlock();
 686 drop_nolock:
 687         kfree_skb(skb);
 688         return 0;
 689 }
 690
 691 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 692 {
 693         struct ip_tunnel *tunnel = netdev_priv(dev);
 694         struct pcpu_tstats *tstats;
 695         const struct iphdr  *old_iph = ip_hdr(skb);
 696         const struct iphdr  *tiph;
 697         struct flowi4 fl4;
 698         u8     tos;
 699         __be16 df;
 700         struct rtable *rt;                      /* Route to the other host */
 701         struct net_device *tdev;                /* Device to other host */
 702         struct iphdr  *iph;                     /* Our new IP header */
 703         unsigned int max_headroom;              /* The extra header space needed */
 704         int    gre_hlen;
 705         __be32 dst;
 706         int    mtu;
 707
 708         if (dev->type == ARPHRD_ETHER)
 709                 IPCB(skb)->flags = 0;
 710
 711         if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
 712                 gre_hlen = 0;
 713                 tiph = (const struct iphdr *)skb->data;
 714         } else {
 715                 gre_hlen = tunnel->hlen;
 716                 tiph = &tunnel->parms.iph;
 717         }
 718
 719         if ((dst = tiph->daddr) == 0) {
 720                 /* NBMA tunnel */
 721
 722                 if (skb_dst(skb) == NULL) {
 723                         dev->stats.tx_fifo_errors++;
 724                         goto tx_error;
 725                 }
 726
 727                 if (skb->protocol == htons(ETH_P_IP)) {
 728                         rt = skb_rtable(skb);
 729                         if ((dst = rt->rt_gateway) == 0)
 730                                 goto tx_error_icmp;
 731                 }
 732 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 733                 else if (skb->protocol == htons(ETH_P_IPV6)) {
 734                         const struct in6_addr *addr6;
 735                         int addr_type;
 736                         struct neighbour *neigh = skb_dst(skb)->neighbour;
 737
 738                         if (neigh == NULL)
 739                                 goto tx_error;
 740
 741                         addr6 = (const struct in6_addr *)&neigh->primary_key;
 742                         addr_type = ipv6_addr_type(addr6);
 743
 744                         if (addr_type == IPV6_ADDR_ANY) {
 745                                 addr6 = &ipv6_hdr(skb)->daddr;
 746                                 addr_type = ipv6_addr_type(addr6);
 747                         }
 748
 749                         if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 750                                 goto tx_error_icmp;
 751
 752                         dst = addr6->s6_addr32[3];
 753                 }
 754 #endif
 755                 else
 756                         goto tx_error;
 757         }
 758
 759         tos = tiph->tos;
 760         if (tos == 1) {
 761                 tos = 0;
 762                 if (skb->protocol == htons(ETH_P_IP))
 763                         tos = old_iph->tos;
 764                 else if (skb->protocol == htons(ETH_P_IPV6))
 765                         tos = ipv6_get_dsfield((const struct ipv6hdr *)old_iph);
 766         }
 767
 768         rt = ip_route_output_gre(dev_net(dev), &fl4, dst, tiph->saddr,
 769                                  tunnel->parms.o_key, RT_TOS(tos),
 770                                  tunnel->parms.link);
 771         if (IS_ERR(rt)) {
 772                 dev->stats.tx_carrier_errors++;
 773                 goto tx_error;
 774         }
 775         tdev = rt->dst.dev;
 776
 777         if (tdev == dev) {
 778                 ip_rt_put(rt);
 779                 dev->stats.collisions++;
 780                 goto tx_error;
 781         }
 782
 783         df = tiph->frag_off;
 784         if (df)
 785                 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - tunnel->hlen;
 786         else
 787                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 788
 789         if (skb_dst(skb))
 790                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 791
 792         if (skb->protocol == htons(ETH_P_IP)) {
 793                 df |= (old_iph->frag_off&htons(IP_DF));
 794
 795                 if ((old_iph->frag_off&htons(IP_DF)) &&
 796                     mtu < ntohs(old_iph->tot_len)) {
 797                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
 798                         ip_rt_put(rt);
 799                         goto tx_error;
 800                 }
 801         }
 802 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 803         else if (skb->protocol == htons(ETH_P_IPV6)) {
 804                 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
 805
 806                 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) {
 807                         if ((tunnel->parms.iph.daddr &&
 808                              !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
 809                             rt6->rt6i_dst.plen == 128) {
 810                                 rt6->rt6i_flags |= RTF_MODIFIED;
 811                                 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
 812                         }
 813                 }
 814
 815                 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
 816                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 817                         ip_rt_put(rt);
 818                         goto tx_error;
 819                 }
 820         }
 821 #endif
 822
 823         if (tunnel->err_count > 0) {
 824                 if (time_before(jiffies,
 825                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 826                         tunnel->err_count--;
 827
 828                         dst_link_failure(skb);
 829                 } else
 830                         tunnel->err_count = 0;
 831         }
 832
 833         max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->dst.header_len;
 834
 835         if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
 836             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 837                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 838                 if (max_headroom > dev->needed_headroom)
 839                         dev->needed_headroom = max_headroom;
 840                 if (!new_skb) {
 841                         ip_rt_put(rt);
 842                         dev->stats.tx_dropped++;
 843                         dev_kfree_skb(skb);
 844                         return NETDEV_TX_OK;
 845                 }
 846                 if (skb->sk)
 847                         skb_set_owner_w(new_skb, skb->sk);
 848                 dev_kfree_skb(skb);
 849                 skb = new_skb;
 850                 old_iph = ip_hdr(skb);
 851         }
 852
 853         skb_reset_transport_header(skb);
 854         skb_push(skb, gre_hlen);
 855         skb_reset_network_header(skb);
 856         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 857         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 858                               IPSKB_REROUTED);
 859         skb_dst_drop(skb);
 860         skb_dst_set(skb, &rt->dst);
 861
 862         /*
 863          *      Push down and install the IPIP header.
 864          */
 865
 866         iph                     =       ip_hdr(skb);
 867         iph->version            =       4;
 868         iph->ihl                =       sizeof(struct iphdr) >> 2;
 869         iph->frag_off           =       df;
 870         iph->protocol           =       IPPROTO_GRE;
 871         iph->tos                =       ipgre_ecn_encapsulate(tos, old_iph, skb);
 872         iph->daddr              =       fl4.daddr;
 873         iph->saddr              =       fl4.saddr;
 874
 875         if ((iph->ttl = tiph->ttl) == 0) {
 876                 if (skb->protocol == htons(ETH_P_IP))
 877                         iph->ttl = old_iph->ttl;
 878 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 879                 else if (skb->protocol == htons(ETH_P_IPV6))
 880                         iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit;
 881 #endif
 882                 else
 883                         iph->ttl = ip4_dst_hoplimit(&rt->dst);
 884         }
 885
 886         ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
 887         ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
 888                                    htons(ETH_P_TEB) : skb->protocol;
 889
 890         if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
 891                 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4);
 892
 893                 if (tunnel->parms.o_flags&GRE_SEQ) {
 894                         ++tunnel->o_seqno;
 895                         *ptr = htonl(tunnel->o_seqno);
 896                         ptr--;
 897                 }
 898                 if (tunnel->parms.o_flags&GRE_KEY) {
 899                         *ptr = tunnel->parms.o_key;
 900                         ptr--;
 901                 }
 902                 if (tunnel->parms.o_flags&GRE_CSUM) {
 903                         *ptr = 0;
 904                         *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr));
 905                 }
 906         }
 907
 908         nf_reset(skb);
 909         tstats = this_cpu_ptr(dev->tstats);
 910         __IPTUNNEL_XMIT(tstats, &dev->stats);
 911         return NETDEV_TX_OK;
 912
 913 tx_error_icmp:
 914         dst_link_failure(skb);
 915
 916 tx_error:
 917         dev->stats.tx_errors++;
 918         dev_kfree_skb(skb);
 919         return NETDEV_TX_OK;
 920 }
 921
 922 static int ipgre_tunnel_bind_dev(struct net_device *dev)
 923 {
 924         struct net_device *tdev = NULL;
 925         struct ip_tunnel *tunnel;
 926         const struct iphdr *iph;
 927         int hlen = LL_MAX_HEADER;
 928         int mtu = ETH_DATA_LEN;
 929         int addend = sizeof(struct iphdr) + 4;
 930
 931         tunnel = netdev_priv(dev);
 932         iph = &tunnel->parms.iph;
 933
 934         /* Guess output device to choose reasonable mtu and needed_headroom */
 935
 936         if (iph->daddr) {
 937                 struct flowi4 fl4;
 938                 struct rtable *rt;
 939
 940                 rt = ip_route_output_gre(dev_net(dev), &fl4,
 941                                          iph->daddr, iph->saddr,
 942                                          tunnel->parms.o_key,
 943                                          RT_TOS(iph->tos),
 944                                          tunnel->parms.link);
 945                 if (!IS_ERR(rt)) {
 946                         tdev = rt->dst.dev;
 947                         ip_rt_put(rt);
 948                 }
 949
 950                 if (dev->type != ARPHRD_ETHER)
 951                         dev->flags |= IFF_POINTOPOINT;
 952         }
 953
 954         if (!tdev && tunnel->parms.link)
 955                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 956
 957         if (tdev) {
 958                 hlen = tdev->hard_header_len + tdev->needed_headroom;
 959                 mtu = tdev->mtu;
 960         }
 961         dev->iflink = tunnel->parms.link;
 962
 963         /* Precalculate GRE options length */
 964         if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
 965                 if (tunnel->parms.o_flags&GRE_CSUM)
 966                         addend += 4;
 967                 if (tunnel->parms.o_flags&GRE_KEY)
 968                         addend += 4;
 969                 if (tunnel->parms.o_flags&GRE_SEQ)
 970                         addend += 4;
 971         }
 972         dev->needed_headroom = addend + hlen;
 973         mtu -= dev->hard_header_len + addend;
 974
 975         if (mtu < 68)
 976                 mtu = 68;
 977
 978         tunnel->hlen = addend;
 979
 980         return mtu;
 981 }
 982
 983 static int
 984 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 985 {
 986         int err = 0;
 987         struct ip_tunnel_parm p;
 988         struct ip_tunnel *t;
 989         struct net *net = dev_net(dev);
 990         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 991
 992         switch (cmd) {
 993         case SIOCGETTUNNEL:
 994                 t = NULL;
 995                 if (dev == ign->fb_tunnel_dev) {
 996                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 997                                 err = -EFAULT;
 998                                 break;
 999                         }
1000                         t = ipgre_tunnel_locate(net, &p, 0);
1001                 }
1002                 if (t == NULL)
1003                         t = netdev_priv(dev);
1004                 memcpy(&p, &t->parms, sizeof(p));
1005                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1006                         err = -EFAULT;
1007                 break;
1008
1009         case SIOCADDTUNNEL:
1010         case SIOCCHGTUNNEL:
1011                 err = -EPERM;
1012                 if (!capable(CAP_NET_ADMIN))
1013                         goto done;
1014
1015                 err = -EFAULT;
1016                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1017                         goto done;
1018
1019                 err = -EINVAL;
1020                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
1021                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
1022                     ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
1023                         goto done;
1024                 if (p.iph.ttl)
1025                         p.iph.frag_off |= htons(IP_DF);
1026
1027                 if (!(p.i_flags&GRE_KEY))
1028                         p.i_key = 0;
1029                 if (!(p.o_flags&GRE_KEY))
1030                         p.o_key = 0;
1031
1032                 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1033
1034                 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1035                         if (t != NULL) {
1036                                 if (t->dev != dev) {
1037                                         err = -EEXIST;
1038                                         break;
1039                                 }
1040                         } else {
1041                                 unsigned int nflags = 0;
1042
1043                                 t = netdev_priv(dev);
1044
1045                                 if (ipv4_is_multicast(p.iph.daddr))
1046                                         nflags = IFF_BROADCAST;
1047                                 else if (p.iph.daddr)
1048                                         nflags = IFF_POINTOPOINT;
1049
1050                                 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
1051                                         err = -EINVAL;
1052                                         break;
1053                                 }
1054                                 ipgre_tunnel_unlink(ign, t);
1055                                 synchronize_net();
1056                                 t->parms.iph.saddr = p.iph.saddr;
1057                                 t->parms.iph.daddr = p.iph.daddr;
1058                                 t->parms.i_key = p.i_key;
1059                                 t->parms.o_key = p.o_key;
1060                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1061                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
1062                                 ipgre_tunnel_link(ign, t);
1063                                 netdev_state_change(dev);
1064                         }
1065                 }
1066
1067                 if (t) {
1068                         err = 0;
1069                         if (cmd == SIOCCHGTUNNEL) {
1070                                 t->parms.iph.ttl = p.iph.ttl;
1071                                 t->parms.iph.tos = p.iph.tos;
1072                                 t->parms.iph.frag_off = p.iph.frag_off;
1073                                 if (t->parms.link != p.link) {
1074                                         t->parms.link = p.link;
1075                                         dev->mtu = ipgre_tunnel_bind_dev(dev);
1076                                         netdev_state_change(dev);
1077                                 }
1078                         }
1079                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1080                                 err = -EFAULT;
1081                 } else
1082                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1083                 break;
1084
1085         case SIOCDELTUNNEL:
1086                 err = -EPERM;
1087                 if (!capable(CAP_NET_ADMIN))
1088                         goto done;
1089
1090                 if (dev == ign->fb_tunnel_dev) {
1091                         err = -EFAULT;
1092                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1093                                 goto done;
1094                         err = -ENOENT;
1095                         if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL)
1096                                 goto done;
1097                         err = -EPERM;
1098                         if (t == netdev_priv(ign->fb_tunnel_dev))
1099                                 goto done;
1100                         dev = t->dev;
1101                 }
1102                 unregister_netdevice(dev);
1103                 err = 0;
1104                 break;
1105
1106         default:
1107                 err = -EINVAL;
1108         }
1109
1110 done:
1111         return err;
1112 }
1113
1114 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1115 {
1116         struct ip_tunnel *tunnel = netdev_priv(dev);
1117         if (new_mtu < 68 ||
1118             new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen)
1119                 return -EINVAL;
1120         dev->mtu = new_mtu;
1121         return 0;
1122 }
1123
1124 /* Nice toy. Unfortunately, useless in real life :-)
1125    It allows to construct virtual multiprotocol broadcast "LAN"
1126    over the Internet, provided multicast routing is tuned.
1127
1128
1129    I have no idea was this bicycle invented before me,
1130    so that I had to set ARPHRD_IPGRE to a random value.
1131    I have an impression, that Cisco could make something similar,
1132    but this feature is apparently missing in IOS<=11.2(8).
1133
1134    I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
1135    with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
1136
1137    ping -t 255 224.66.66.66
1138
1139    If nobody answers, mbone does not work.
1140
1141    ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
1142    ip addr add 10.66.66.<somewhat>/24 dev Universe
1143    ifconfig Universe up
1144    ifconfig Universe add fe80::<Your_real_addr>/10
1145    ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
1146    ftp 10.66.66.66
1147    ...
1148    ftp fec0:6666:6666::193.233.7.65
1149    ...
1150
1151  */
1152
1153 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
1154                         unsigned short type,
1155                         const void *daddr, const void *saddr, unsigned int len)
1156 {
1157         struct ip_tunnel *t = netdev_priv(dev);
1158         struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
1159         __be16 *p = (__be16*)(iph+1);
1160
1161         memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
1162         p[0]            = t->parms.o_flags;
1163         p[1]            = htons(type);
1164
1165         /*
1166          *      Set the source hardware address.
1167          */
1168
1169         if (saddr)
1170                 memcpy(&iph->saddr, saddr, 4);
1171         if (daddr)
1172                 memcpy(&iph->daddr, daddr, 4);
1173         if (iph->daddr)
1174                 return t->hlen;
1175
1176         return -t->hlen;
1177 }
1178
1179 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
1180 {
1181         const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
1182         memcpy(haddr, &iph->saddr, 4);
1183         return 4;
1184 }
1185
1186 static const struct header_ops ipgre_header_ops = {
1187         .create = ipgre_header,
1188         .parse  = ipgre_header_parse,
1189 };
1190
1191 #ifdef CONFIG_NET_IPGRE_BROADCAST
1192 static int ipgre_open(struct net_device *dev)
1193 {
1194         struct ip_tunnel *t = netdev_priv(dev);
1195
1196         if (ipv4_is_multicast(t->parms.iph.daddr)) {
1197                 struct flowi4 fl4;
1198                 struct rtable *rt;
1199
1200                 rt = ip_route_output_gre(dev_net(dev), &fl4,
1201                                          t->parms.iph.daddr,
1202                                          t->parms.iph.saddr,
1203                                          t->parms.o_key,
1204                                          RT_TOS(t->parms.iph.tos),
1205                                          t->parms.link);
1206                 if (IS_ERR(rt))
1207                         return -EADDRNOTAVAIL;
1208                 dev = rt->dst.dev;
1209                 ip_rt_put(rt);
1210                 if (__in_dev_get_rtnl(dev) == NULL)
1211                         return -EADDRNOTAVAIL;
1212                 t->mlink = dev->ifindex;
1213                 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
1214         }
1215         return 0;
1216 }
1217
1218 static int ipgre_close(struct net_device *dev)
1219 {
1220         struct ip_tunnel *t = netdev_priv(dev);
1221
1222         if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
1223                 struct in_device *in_dev;
1224                 in_dev = inetdev_by_index(dev_net(dev), t->mlink);
1225                 if (in_dev)
1226                         ip_mc_dec_group(in_dev, t->parms.iph.daddr);
1227         }
1228         return 0;
1229 }
1230
1231 #endif
1232
1233 static const struct net_device_ops ipgre_netdev_ops = {
1234         .ndo_init               = ipgre_tunnel_init,
1235         .ndo_uninit             = ipgre_tunnel_uninit,
1236 #ifdef CONFIG_NET_IPGRE_BROADCAST
1237         .ndo_open               = ipgre_open,
1238         .ndo_stop               = ipgre_close,
1239 #endif
1240         .ndo_start_xmit         = ipgre_tunnel_xmit,
1241         .ndo_do_ioctl           = ipgre_tunnel_ioctl,
1242         .ndo_change_mtu         = ipgre_tunnel_change_mtu,
1243         .ndo_get_stats          = ipgre_get_stats,
1244 };
1245
1246 static void ipgre_dev_free(struct net_device *dev)
1247 {
1248         free_percpu(dev->tstats);
1249         free_netdev(dev);
1250 }
1251
1252 static void ipgre_tunnel_setup(struct net_device *dev)
1253 {
1254         dev->netdev_ops         = &ipgre_netdev_ops;
1255         dev->destructor         = ipgre_dev_free;
1256
1257         dev->type               = ARPHRD_IPGRE;
1258         dev->needed_headroom    = LL_MAX_HEADER + sizeof(struct iphdr) + 4;
1259         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr) - 4;
1260         dev->flags              = IFF_NOARP;
1261         dev->iflink             = 0;
1262         dev->addr_len           = 4;
1263         dev->features           |= NETIF_F_NETNS_LOCAL;
1264         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
1265 }
1266
1267 static int ipgre_tunnel_init(struct net_device *dev)
1268 {
1269         struct ip_tunnel *tunnel;
1270         struct iphdr *iph;
1271
1272         tunnel = netdev_priv(dev);
1273         iph = &tunnel->parms.iph;
1274
1275         tunnel->dev = dev;
1276         strcpy(tunnel->parms.name, dev->name);
1277
1278         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1279         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1280
1281         if (iph->daddr) {
1282 #ifdef CONFIG_NET_IPGRE_BROADCAST
1283                 if (ipv4_is_multicast(iph->daddr)) {
1284                         if (!iph->saddr)
1285                                 return -EINVAL;
1286                         dev->flags = IFF_BROADCAST;
1287                         dev->header_ops = &ipgre_header_ops;
1288                 }
1289 #endif
1290         } else
1291                 dev->header_ops = &ipgre_header_ops;
1292
1293         dev->tstats = alloc_percpu(struct pcpu_tstats);
1294         if (!dev->tstats)
1295                 return -ENOMEM;
1296
1297         return 0;
1298 }
1299
1300 static void ipgre_fb_tunnel_init(struct net_device *dev)
1301 {
1302         struct ip_tunnel *tunnel = netdev_priv(dev);
1303         struct iphdr *iph = &tunnel->parms.iph;
1304
1305         tunnel->dev = dev;
1306         strcpy(tunnel->parms.name, dev->name);
1307
1308         iph->version            = 4;
1309         iph->protocol           = IPPROTO_GRE;
1310         iph->ihl                = 5;
1311         tunnel->hlen            = sizeof(struct iphdr) + 4;
1312
1313         dev_hold(dev);
1314 }
1315
1316
1317 static const struct gre_protocol ipgre_protocol = {
1318         .handler     = ipgre_rcv,
1319         .err_handler = ipgre_err,
1320 };
1321
1322 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head)
1323 {
1324         int prio;
1325
1326         for (prio = 0; prio < 4; prio++) {
1327                 int h;
1328                 for (h = 0; h < HASH_SIZE; h++) {
1329                         struct ip_tunnel *t;
1330
1331                         t = rtnl_dereference(ign->tunnels[prio][h]);
1332
1333                         while (t != NULL) {
1334                                 unregister_netdevice_queue(t->dev, head);
1335                                 t = rtnl_dereference(t->next);
1336                         }
1337                 }
1338         }
1339 }
1340
1341 static int __net_init ipgre_init_net(struct net *net)
1342 {
1343         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1344         int err;
1345
1346         ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0",
1347                                            ipgre_tunnel_setup);
1348         if (!ign->fb_tunnel_dev) {
1349                 err = -ENOMEM;
1350                 goto err_alloc_dev;
1351         }
1352         dev_net_set(ign->fb_tunnel_dev, net);
1353
1354         ipgre_fb_tunnel_init(ign->fb_tunnel_dev);
1355         ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops;
1356
1357         if ((err = register_netdev(ign->fb_tunnel_dev)))
1358                 goto err_reg_dev;
1359
1360         rcu_assign_pointer(ign->tunnels_wc[0],
1361                            netdev_priv(ign->fb_tunnel_dev));
1362         return 0;
1363
1364 err_reg_dev:
1365         ipgre_dev_free(ign->fb_tunnel_dev);
1366 err_alloc_dev:
1367         return err;
1368 }
1369
1370 static void __net_exit ipgre_exit_net(struct net *net)
1371 {
1372         struct ipgre_net *ign;
1373         LIST_HEAD(list);
1374
1375         ign = net_generic(net, ipgre_net_id);
1376         rtnl_lock();
1377         ipgre_destroy_tunnels(ign, &list);
1378         unregister_netdevice_many(&list);
1379         rtnl_unlock();
1380 }
1381
1382 static struct pernet_operations ipgre_net_ops = {
1383         .init = ipgre_init_net,
1384         .exit = ipgre_exit_net,
1385         .id   = &ipgre_net_id,
1386         .size = sizeof(struct ipgre_net),
1387 };
1388
1389 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
1390 {
1391         __be16 flags;
1392
1393         if (!data)
1394                 return 0;
1395
1396         flags = 0;
1397         if (data[IFLA_GRE_IFLAGS])
1398                 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1399         if (data[IFLA_GRE_OFLAGS])
1400                 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1401         if (flags & (GRE_VERSION|GRE_ROUTING))
1402                 return -EINVAL;
1403
1404         return 0;
1405 }
1406
1407 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[])
1408 {
1409         __be32 daddr;
1410
1411         if (tb[IFLA_ADDRESS]) {
1412                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1413                         return -EINVAL;
1414                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1415                         return -EADDRNOTAVAIL;
1416         }
1417
1418         if (!data)
1419                 goto out;
1420
1421         if (data[IFLA_GRE_REMOTE]) {
1422                 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1423                 if (!daddr)
1424                         return -EINVAL;
1425         }
1426
1427 out:
1428         return ipgre_tunnel_validate(tb, data);
1429 }
1430
1431 static void ipgre_netlink_parms(struct nlattr *data[],
1432                                 struct ip_tunnel_parm *parms)
1433 {
1434         memset(parms, 0, sizeof(*parms));
1435
1436         parms->iph.protocol = IPPROTO_GRE;
1437
1438         if (!data)
1439                 return;
1440
1441         if (data[IFLA_GRE_LINK])
1442                 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1443
1444         if (data[IFLA_GRE_IFLAGS])
1445                 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]);
1446
1447         if (data[IFLA_GRE_OFLAGS])
1448                 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]);
1449
1450         if (data[IFLA_GRE_IKEY])
1451                 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1452
1453         if (data[IFLA_GRE_OKEY])
1454                 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1455
1456         if (data[IFLA_GRE_LOCAL])
1457                 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]);
1458
1459         if (data[IFLA_GRE_REMOTE])
1460                 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]);
1461
1462         if (data[IFLA_GRE_TTL])
1463                 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1464
1465         if (data[IFLA_GRE_TOS])
1466                 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1467
1468         if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC]))
1469                 parms->iph.frag_off = htons(IP_DF);
1470 }
1471
1472 static int ipgre_tap_init(struct net_device *dev)
1473 {
1474         struct ip_tunnel *tunnel;
1475
1476         tunnel = netdev_priv(dev);
1477
1478         tunnel->dev = dev;
1479         strcpy(tunnel->parms.name, dev->name);
1480
1481         ipgre_tunnel_bind_dev(dev);
1482
1483         dev->tstats = alloc_percpu(struct pcpu_tstats);
1484         if (!dev->tstats)
1485                 return -ENOMEM;
1486
1487         return 0;
1488 }
1489
1490 static const struct net_device_ops ipgre_tap_netdev_ops = {
1491         .ndo_init               = ipgre_tap_init,
1492         .ndo_uninit             = ipgre_tunnel_uninit,
1493         .ndo_start_xmit         = ipgre_tunnel_xmit,
1494         .ndo_set_mac_address    = eth_mac_addr,
1495         .ndo_validate_addr      = eth_validate_addr,
1496         .ndo_change_mtu         = ipgre_tunnel_change_mtu,
1497         .ndo_get_stats          = ipgre_get_stats,
1498 };
1499
1500 static void ipgre_tap_setup(struct net_device *dev)
1501 {
1502
1503         ether_setup(dev);
1504
1505         dev->netdev_ops         = &ipgre_tap_netdev_ops;
1506         dev->destructor         = ipgre_dev_free;
1507
1508         dev->iflink             = 0;
1509         dev->features           |= NETIF_F_NETNS_LOCAL;
1510 }
1511
1512 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[],
1513                          struct nlattr *data[])
1514 {
1515         struct ip_tunnel *nt;
1516         struct net *net = dev_net(dev);
1517         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1518         int mtu;
1519         int err;
1520
1521         nt = netdev_priv(dev);
1522         ipgre_netlink_parms(data, &nt->parms);
1523
1524         if (ipgre_tunnel_find(net, &nt->parms, dev->type))
1525                 return -EEXIST;
1526
1527         if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1528                 random_ether_addr(dev->dev_addr);
1529
1530         mtu = ipgre_tunnel_bind_dev(dev);
1531         if (!tb[IFLA_MTU])
1532                 dev->mtu = mtu;
1533
1534         /* Can use a lockless transmit, unless we generate output sequences */
1535         if (!(nt->parms.o_flags & GRE_SEQ))
1536                 dev->features |= NETIF_F_LLTX;
1537
1538         err = register_netdevice(dev);
1539         if (err)
1540                 goto out;
1541
1542         dev_hold(dev);
1543         ipgre_tunnel_link(ign, nt);
1544
1545 out:
1546         return err;
1547 }
1548
1549 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1550                             struct nlattr *data[])
1551 {
1552         struct ip_tunnel *t, *nt;
1553         struct net *net = dev_net(dev);
1554         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
1555         struct ip_tunnel_parm p;
1556         int mtu;
1557
1558         if (dev == ign->fb_tunnel_dev)
1559                 return -EINVAL;
1560
1561         nt = netdev_priv(dev);
1562         ipgre_netlink_parms(data, &p);
1563
1564         t = ipgre_tunnel_locate(net, &p, 0);
1565
1566         if (t) {
1567                 if (t->dev != dev)
1568                         return -EEXIST;
1569         } else {
1570                 t = nt;
1571
1572                 if (dev->type != ARPHRD_ETHER) {
1573                         unsigned int nflags = 0;
1574
1575                         if (ipv4_is_multicast(p.iph.daddr))
1576                                 nflags = IFF_BROADCAST;
1577                         else if (p.iph.daddr)
1578                                 nflags = IFF_POINTOPOINT;
1579
1580                         if ((dev->flags ^ nflags) &
1581                             (IFF_POINTOPOINT | IFF_BROADCAST))
1582                                 return -EINVAL;
1583                 }
1584
1585                 ipgre_tunnel_unlink(ign, t);
1586                 t->parms.iph.saddr = p.iph.saddr;
1587                 t->parms.iph.daddr = p.iph.daddr;
1588                 t->parms.i_key = p.i_key;
1589                 if (dev->type != ARPHRD_ETHER) {
1590                         memcpy(dev->dev_addr, &p.iph.saddr, 4);
1591                         memcpy(dev->broadcast, &p.iph.daddr, 4);
1592                 }
1593                 ipgre_tunnel_link(ign, t);
1594                 netdev_state_change(dev);
1595         }
1596
1597         t->parms.o_key = p.o_key;
1598         t->parms.iph.ttl = p.iph.ttl;
1599         t->parms.iph.tos = p.iph.tos;
1600         t->parms.iph.frag_off = p.iph.frag_off;
1601
1602         if (t->parms.link != p.link) {
1603                 t->parms.link = p.link;
1604                 mtu = ipgre_tunnel_bind_dev(dev);
1605                 if (!tb[IFLA_MTU])
1606                         dev->mtu = mtu;
1607                 netdev_state_change(dev);
1608         }
1609
1610         return 0;
1611 }
1612
1613 static size_t ipgre_get_size(const struct net_device *dev)
1614 {
1615         return
1616                 /* IFLA_GRE_LINK */
1617                 nla_total_size(4) +
1618                 /* IFLA_GRE_IFLAGS */
1619                 nla_total_size(2) +
1620                 /* IFLA_GRE_OFLAGS */
1621                 nla_total_size(2) +
1622                 /* IFLA_GRE_IKEY */
1623                 nla_total_size(4) +
1624                 /* IFLA_GRE_OKEY */
1625                 nla_total_size(4) +
1626                 /* IFLA_GRE_LOCAL */
1627                 nla_total_size(4) +
1628                 /* IFLA_GRE_REMOTE */
1629                 nla_total_size(4) +
1630                 /* IFLA_GRE_TTL */
1631                 nla_total_size(1) +
1632                 /* IFLA_GRE_TOS */
1633                 nla_total_size(1) +
1634                 /* IFLA_GRE_PMTUDISC */
1635                 nla_total_size(1) +
1636                 0;
1637 }
1638
1639 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1640 {
1641         struct ip_tunnel *t = netdev_priv(dev);
1642         struct ip_tunnel_parm *p = &t->parms;
1643
1644         NLA_PUT_U32(skb, IFLA_GRE_LINK, p->link);
1645         NLA_PUT_BE16(skb, IFLA_GRE_IFLAGS, p->i_flags);
1646         NLA_PUT_BE16(skb, IFLA_GRE_OFLAGS, p->o_flags);
1647         NLA_PUT_BE32(skb, IFLA_GRE_IKEY, p->i_key);
1648         NLA_PUT_BE32(skb, IFLA_GRE_OKEY, p->o_key);
1649         NLA_PUT_BE32(skb, IFLA_GRE_LOCAL, p->iph.saddr);
1650         NLA_PUT_BE32(skb, IFLA_GRE_REMOTE, p->iph.daddr);
1651         NLA_PUT_U8(skb, IFLA_GRE_TTL, p->iph.ttl);
1652         NLA_PUT_U8(skb, IFLA_GRE_TOS, p->iph.tos);
1653         NLA_PUT_U8(skb, IFLA_GRE_PMTUDISC, !!(p->iph.frag_off & htons(IP_DF)));
1654
1655         return 0;
1656
1657 nla_put_failure:
1658         return -EMSGSIZE;
1659 }
1660
1661 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1662         [IFLA_GRE_LINK]         = { .type = NLA_U32 },
1663         [IFLA_GRE_IFLAGS]       = { .type = NLA_U16 },
1664         [IFLA_GRE_OFLAGS]       = { .type = NLA_U16 },
1665         [IFLA_GRE_IKEY]         = { .type = NLA_U32 },
1666         [IFLA_GRE_OKEY]         = { .type = NLA_U32 },
1667         [IFLA_GRE_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1668         [IFLA_GRE_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1669         [IFLA_GRE_TTL]          = { .type = NLA_U8 },
1670         [IFLA_GRE_TOS]          = { .type = NLA_U8 },
1671         [IFLA_GRE_PMTUDISC]     = { .type = NLA_U8 },
1672 };
1673
1674 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1675         .kind           = "gre",
1676         .maxtype        = IFLA_GRE_MAX,
1677         .policy         = ipgre_policy,
1678         .priv_size      = sizeof(struct ip_tunnel),
1679         .setup          = ipgre_tunnel_setup,
1680         .validate       = ipgre_tunnel_validate,
1681         .newlink        = ipgre_newlink,
1682         .changelink     = ipgre_changelink,
1683         .get_size       = ipgre_get_size,
1684         .fill_info      = ipgre_fill_info,
1685 };
1686
1687 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1688         .kind           = "gretap",
1689         .maxtype        = IFLA_GRE_MAX,
1690         .policy         = ipgre_policy,
1691         .priv_size      = sizeof(struct ip_tunnel),
1692         .setup          = ipgre_tap_setup,
1693         .validate       = ipgre_tap_validate,
1694         .newlink        = ipgre_newlink,
1695         .changelink     = ipgre_changelink,
1696         .get_size       = ipgre_get_size,
1697         .fill_info      = ipgre_fill_info,
1698 };
1699
1700 /*
1701  *      And now the modules code and kernel interface.
1702  */
1703
1704 static int __init ipgre_init(void)
1705 {
1706         int err;
1707
1708         printk(KERN_INFO "GRE over IPv4 tunneling driver\n");
1709
1710         err = register_pernet_device(&ipgre_net_ops);
1711         if (err < 0)
1712                 return err;
1713
1714         err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1715         if (err < 0) {
1716                 printk(KERN_INFO "ipgre init: can't add protocol\n");
1717                 goto add_proto_failed;
1718         }
1719
1720         err = rtnl_link_register(&ipgre_link_ops);
1721         if (err < 0)
1722                 goto rtnl_link_failed;
1723
1724         err = rtnl_link_register(&ipgre_tap_ops);
1725         if (err < 0)
1726                 goto tap_ops_failed;
1727
1728 out:
1729         return err;
1730
1731 tap_ops_failed:
1732         rtnl_link_unregister(&ipgre_link_ops);
1733 rtnl_link_failed:
1734         gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1735 add_proto_failed:
1736         unregister_pernet_device(&ipgre_net_ops);
1737         goto out;
1738 }
1739
1740 static void __exit ipgre_fini(void)
1741 {
1742         rtnl_link_unregister(&ipgre_tap_ops);
1743         rtnl_link_unregister(&ipgre_link_ops);
1744         if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0)
1745                 printk(KERN_INFO "ipgre close: can't remove protocol\n");
1746         unregister_pernet_device(&ipgre_net_ops);
1747 }
1748
1749 module_init(ipgre_init);
1750 module_exit(ipgre_fini);
1751 MODULE_LICENSE("GPL");
1752 MODULE_ALIAS_RTNL_LINK("gre");
1753 MODULE_ALIAS_RTNL_LINK("gretap");
1754 MODULE_ALIAS_NETDEV("gre0");