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         if (strchr(name, '%')) {
 417                 if (dev_alloc_name(dev, name) < 0)
 418                         goto failed_free;
 419         }
 420
 421         nt = netdev_priv(dev);
 422         nt->parms = *parms;
 423         dev->rtnl_link_ops = &ipgre_link_ops;
 424
 425         dev->mtu = ipgre_tunnel_bind_dev(dev);
 426
 427         if (register_netdevice(dev) < 0)
 428                 goto failed_free;
 429
 430         dev_hold(dev);
 431         ipgre_tunnel_link(ign, nt);
 432         return nt;
 433
 434 failed_free:
 435         free_netdev(dev);
 436         return NULL;
 437 }
 438
 439 static void ipgre_tunnel_uninit(struct net_device *dev)
 440 {
 441         struct net *net = dev_net(dev);
 442         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 443
 444         ipgre_tunnel_unlink(ign, netdev_priv(dev));
 445         dev_put(dev);
 446 }
 447
 448
 449 static void ipgre_err(struct sk_buff *skb, u32 info)
 450 {
 451
 452 /* All the routers (except for Linux) return only
 453    8 bytes of packet payload. It means, that precise relaying of
 454    ICMP in the real Internet is absolutely infeasible.
 455
 456    Moreover, Cisco "wise men" put GRE key to the third word
 457    in GRE header. It makes impossible maintaining even soft state for keyed
 458    GRE tunnels with enabled checksum. Tell them "thank you".
 459
 460    Well, I wonder, rfc1812 was written by Cisco employee,
 461    what the hell these idiots break standrads established
 462    by themself???
 463  */
 464
 465         struct iphdr *iph = (struct iphdr *)skb->data;
 466         __be16       *p = (__be16*)(skb->data+(iph->ihl<<2));
 467         int grehlen = (iph->ihl<<2) + 4;
 468         const int type = icmp_hdr(skb)->type;
 469         const int code = icmp_hdr(skb)->code;
 470         struct ip_tunnel *t;
 471         __be16 flags;
 472
 473         flags = p[0];
 474         if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) {
 475                 if (flags&(GRE_VERSION|GRE_ROUTING))
 476                         return;
 477                 if (flags&GRE_KEY) {
 478                         grehlen += 4;
 479                         if (flags&GRE_CSUM)
 480                                 grehlen += 4;
 481                 }
 482         }
 483
 484         /* If only 8 bytes returned, keyed message will be dropped here */
 485         if (skb_headlen(skb) < grehlen)
 486                 return;
 487
 488         switch (type) {
 489         default:
 490         case ICMP_PARAMETERPROB:
 491                 return;
 492
 493         case ICMP_DEST_UNREACH:
 494                 switch (code) {
 495                 case ICMP_SR_FAILED:
 496                 case ICMP_PORT_UNREACH:
 497                         /* Impossible event. */
 498                         return;
 499                 case ICMP_FRAG_NEEDED:
 500                         /* Soft state for pmtu is maintained by IP core. */
 501                         return;
 502                 default:
 503                         /* All others are translated to HOST_UNREACH.
 504                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 505                            I believe they are just ether pollution. --ANK
 506                          */
 507                         break;
 508                 }
 509                 break;
 510         case ICMP_TIME_EXCEEDED:
 511                 if (code != ICMP_EXC_TTL)
 512                         return;
 513                 break;
 514         }
 515
 516         rcu_read_lock();
 517         t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr,
 518                                 flags & GRE_KEY ?
 519                                 *(((__be32 *)p) + (grehlen / 4) - 1) : 0,
 520                                 p[1]);
 521         if (t == NULL || t->parms.iph.daddr == 0 ||
 522             ipv4_is_multicast(t->parms.iph.daddr))
 523                 goto out;
 524
 525         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 526                 goto out;
 527
 528         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 529                 t->err_count++;
 530         else
 531                 t->err_count = 1;
 532         t->err_time = jiffies;
 533 out:
 534         rcu_read_unlock();
 535 }
 536
 537 static inline void ipgre_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
 538 {
 539         if (INET_ECN_is_ce(iph->tos)) {
 540                 if (skb->protocol == htons(ETH_P_IP)) {
 541                         IP_ECN_set_ce(ip_hdr(skb));
 542                 } else if (skb->protocol == htons(ETH_P_IPV6)) {
 543                         IP6_ECN_set_ce(ipv6_hdr(skb));
 544                 }
 545         }
 546 }
 547
 548 static inline u8
 549 ipgre_ecn_encapsulate(u8 tos, struct iphdr *old_iph, struct sk_buff *skb)
 550 {
 551         u8 inner = 0;
 552         if (skb->protocol == htons(ETH_P_IP))
 553                 inner = old_iph->tos;
 554         else if (skb->protocol == htons(ETH_P_IPV6))
 555                 inner = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
 556         return INET_ECN_encapsulate(tos, inner);
 557 }
 558
 559 static int ipgre_rcv(struct sk_buff *skb)
 560 {
 561         struct iphdr *iph;
 562         u8     *h;
 563         __be16    flags;
 564         __sum16   csum = 0;
 565         __be32 key = 0;
 566         u32    seqno = 0;
 567         struct ip_tunnel *tunnel;
 568         int    offset = 4;
 569         __be16 gre_proto;
 570
 571         if (!pskb_may_pull(skb, 16))
 572                 goto drop_nolock;
 573
 574         iph = ip_hdr(skb);
 575         h = skb->data;
 576         flags = *(__be16*)h;
 577
 578         if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) {
 579                 /* - Version must be 0.
 580                    - We do not support routing headers.
 581                  */
 582                 if (flags&(GRE_VERSION|GRE_ROUTING))
 583                         goto drop_nolock;
 584
 585                 if (flags&GRE_CSUM) {
 586                         switch (skb->ip_summed) {
 587                         case CHECKSUM_COMPLETE:
 588                                 csum = csum_fold(skb->csum);
 589                                 if (!csum)
 590                                         break;
 591                                 /* fall through */
 592                         case CHECKSUM_NONE:
 593                                 skb->csum = 0;
 594                                 csum = __skb_checksum_complete(skb);
 595                                 skb->ip_summed = CHECKSUM_COMPLETE;
 596                         }
 597                         offset += 4;
 598                 }
 599                 if (flags&GRE_KEY) {
 600                         key = *(__be32*)(h + offset);
 601                         offset += 4;
 602                 }
 603                 if (flags&GRE_SEQ) {
 604                         seqno = ntohl(*(__be32*)(h + offset));
 605                         offset += 4;
 606                 }
 607         }
 608
 609         gre_proto = *(__be16 *)(h + 2);
 610
 611         rcu_read_lock();
 612         if ((tunnel = ipgre_tunnel_lookup(skb->dev,
 613                                           iph->saddr, iph->daddr, key,
 614                                           gre_proto))) {
 615                 struct pcpu_tstats *tstats;
 616
 617                 secpath_reset(skb);
 618
 619                 skb->protocol = gre_proto;
 620                 /* WCCP version 1 and 2 protocol decoding.
 621                  * - Change protocol to IP
 622                  * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header
 623                  */
 624                 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) {
 625                         skb->protocol = htons(ETH_P_IP);
 626                         if ((*(h + offset) & 0xF0) != 0x40)
 627                                 offset += 4;
 628                 }
 629
 630                 skb->mac_header = skb->network_header;
 631                 __pskb_pull(skb, offset);
 632                 skb_postpull_rcsum(skb, skb_transport_header(skb), offset);
 633                 skb->pkt_type = PACKET_HOST;
 634 #ifdef CONFIG_NET_IPGRE_BROADCAST
 635                 if (ipv4_is_multicast(iph->daddr)) {
 636                         /* Looped back packet, drop it! */
 637                         if (rt_is_output_route(skb_rtable(skb)))
 638                                 goto drop;
 639                         tunnel->dev->stats.multicast++;
 640                         skb->pkt_type = PACKET_BROADCAST;
 641                 }
 642 #endif
 643
 644                 if (((flags&GRE_CSUM) && csum) ||
 645                     (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) {
 646                         tunnel->dev->stats.rx_crc_errors++;
 647                         tunnel->dev->stats.rx_errors++;
 648                         goto drop;
 649                 }
 650                 if (tunnel->parms.i_flags&GRE_SEQ) {
 651                         if (!(flags&GRE_SEQ) ||
 652                             (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) {
 653                                 tunnel->dev->stats.rx_fifo_errors++;
 654                                 tunnel->dev->stats.rx_errors++;
 655                                 goto drop;
 656                         }
 657                         tunnel->i_seqno = seqno + 1;
 658                 }
 659
 660                 /* Warning: All skb pointers will be invalidated! */
 661                 if (tunnel->dev->type == ARPHRD_ETHER) {
 662                         if (!pskb_may_pull(skb, ETH_HLEN)) {
 663                                 tunnel->dev->stats.rx_length_errors++;
 664                                 tunnel->dev->stats.rx_errors++;
 665                                 goto drop;
 666                         }
 667
 668                         iph = ip_hdr(skb);
 669                         skb->protocol = eth_type_trans(skb, tunnel->dev);
 670                         skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
 671                 }
 672
 673                 tstats = this_cpu_ptr(tunnel->dev->tstats);
 674                 tstats->rx_packets++;
 675                 tstats->rx_bytes += skb->len;
 676
 677                 __skb_tunnel_rx(skb, tunnel->dev);
 678
 679                 skb_reset_network_header(skb);
 680                 ipgre_ecn_decapsulate(iph, skb);
 681
 682                 netif_rx(skb);
 683
 684                 rcu_read_unlock();
 685                 return 0;
 686         }
 687         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 688
 689 drop:
 690         rcu_read_unlock();
 691 drop_nolock:
 692         kfree_skb(skb);
 693         return 0;
 694 }
 695
 696 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 697 {
 698         struct ip_tunnel *tunnel = netdev_priv(dev);
 699         struct pcpu_tstats *tstats;
 700         struct iphdr  *old_iph = ip_hdr(skb);
 701         struct iphdr  *tiph;
 702         u8     tos;
 703         __be16 df;
 704         struct rtable *rt;                      /* Route to the other host */
 705         struct net_device *tdev;                /* Device to other host */
 706         struct iphdr  *iph;                     /* Our new IP header */
 707         unsigned int max_headroom;              /* The extra header space needed */
 708         int    gre_hlen;
 709         __be32 dst;
 710         int    mtu;
 711
 712         if (dev->type == ARPHRD_ETHER)
 713                 IPCB(skb)->flags = 0;
 714
 715         if (dev->header_ops && dev->type == ARPHRD_IPGRE) {
 716                 gre_hlen = 0;
 717                 tiph = (struct iphdr *)skb->data;
 718         } else {
 719                 gre_hlen = tunnel->hlen;
 720                 tiph = &tunnel->parms.iph;
 721         }
 722
 723         if ((dst = tiph->daddr) == 0) {
 724                 /* NBMA tunnel */
 725
 726                 if (skb_dst(skb) == NULL) {
 727                         dev->stats.tx_fifo_errors++;
 728                         goto tx_error;
 729                 }
 730
 731                 if (skb->protocol == htons(ETH_P_IP)) {
 732                         rt = skb_rtable(skb);
 733                         if ((dst = rt->rt_gateway) == 0)
 734                                 goto tx_error_icmp;
 735                 }
 736 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 737                 else if (skb->protocol == htons(ETH_P_IPV6)) {
 738                         struct in6_addr *addr6;
 739                         int addr_type;
 740                         struct neighbour *neigh = skb_dst(skb)->neighbour;
 741
 742                         if (neigh == NULL)
 743                                 goto tx_error;
 744
 745                         addr6 = (struct in6_addr *)&neigh->primary_key;
 746                         addr_type = ipv6_addr_type(addr6);
 747
 748                         if (addr_type == IPV6_ADDR_ANY) {
 749                                 addr6 = &ipv6_hdr(skb)->daddr;
 750                                 addr_type = ipv6_addr_type(addr6);
 751                         }
 752
 753                         if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 754                                 goto tx_error_icmp;
 755
 756                         dst = addr6->s6_addr32[3];
 757                 }
 758 #endif
 759                 else
 760                         goto tx_error;
 761         }
 762
 763         tos = tiph->tos;
 764         if (tos == 1) {
 765                 tos = 0;
 766                 if (skb->protocol == htons(ETH_P_IP))
 767                         tos = old_iph->tos;
 768                 else if (skb->protocol == htons(ETH_P_IPV6))
 769                         tos = ipv6_get_dsfield((struct ipv6hdr *)old_iph);
 770         }
 771
 772         rt = ip_route_output_gre(dev_net(dev), dst, tiph->saddr,
 773                                  tunnel->parms.o_key, RT_TOS(tos),
 774                                  tunnel->parms.link);
 775         if (IS_ERR(rt)) {
 776                 dev->stats.tx_carrier_errors++;
 777                 goto tx_error;
 778         }
 779         tdev = rt->dst.dev;
 780
 781         if (tdev == dev) {
 782                 ip_rt_put(rt);
 783                 dev->stats.collisions++;
 784                 goto tx_error;
 785         }
 786
 787         df = tiph->frag_off;
 788         if (df)
 789                 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - tunnel->hlen;
 790         else
 791                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 792
 793         if (skb_dst(skb))
 794                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
 795
 796         if (skb->protocol == htons(ETH_P_IP)) {
 797                 df |= (old_iph->frag_off&htons(IP_DF));
 798
 799                 if ((old_iph->frag_off&htons(IP_DF)) &&
 800                     mtu < ntohs(old_iph->tot_len)) {
 801                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
 802                         ip_rt_put(rt);
 803                         goto tx_error;
 804                 }
 805         }
 806 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 807         else if (skb->protocol == htons(ETH_P_IPV6)) {
 808                 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
 809
 810                 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) {
 811                         if ((tunnel->parms.iph.daddr &&
 812                              !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
 813                             rt6->rt6i_dst.plen == 128) {
 814                                 rt6->rt6i_flags |= RTF_MODIFIED;
 815                                 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
 816                         }
 817                 }
 818
 819                 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) {
 820                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 821                         ip_rt_put(rt);
 822                         goto tx_error;
 823                 }
 824         }
 825 #endif
 826
 827         if (tunnel->err_count > 0) {
 828                 if (time_before(jiffies,
 829                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 830                         tunnel->err_count--;
 831
 832                         dst_link_failure(skb);
 833                 } else
 834                         tunnel->err_count = 0;
 835         }
 836
 837         max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->dst.header_len;
 838
 839         if (skb_headroom(skb) < max_headroom || skb_shared(skb)||
 840             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
 841                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
 842                 if (max_headroom > dev->needed_headroom)
 843                         dev->needed_headroom = max_headroom;
 844                 if (!new_skb) {
 845                         ip_rt_put(rt);
 846                         dev->stats.tx_dropped++;
 847                         dev_kfree_skb(skb);
 848                         return NETDEV_TX_OK;
 849                 }
 850                 if (skb->sk)
 851                         skb_set_owner_w(new_skb, skb->sk);
 852                 dev_kfree_skb(skb);
 853                 skb = new_skb;
 854                 old_iph = ip_hdr(skb);
 855         }
 856
 857         skb_reset_transport_header(skb);
 858         skb_push(skb, gre_hlen);
 859         skb_reset_network_header(skb);
 860         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 861         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
 862                               IPSKB_REROUTED);
 863         skb_dst_drop(skb);
 864         skb_dst_set(skb, &rt->dst);
 865
 866         /*
 867          *      Push down and install the IPIP header.
 868          */
 869
 870         iph                     =       ip_hdr(skb);
 871         iph->version            =       4;
 872         iph->ihl                =       sizeof(struct iphdr) >> 2;
 873         iph->frag_off           =       df;
 874         iph->protocol           =       IPPROTO_GRE;
 875         iph->tos                =       ipgre_ecn_encapsulate(tos, old_iph, skb);
 876         iph->daddr              =       rt->rt_dst;
 877         iph->saddr              =       rt->rt_src;
 878
 879         if ((iph->ttl = tiph->ttl) == 0) {
 880                 if (skb->protocol == htons(ETH_P_IP))
 881                         iph->ttl = old_iph->ttl;
 882 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
 883                 else if (skb->protocol == htons(ETH_P_IPV6))
 884                         iph->ttl = ((struct ipv6hdr *)old_iph)->hop_limit;
 885 #endif
 886                 else
 887                         iph->ttl = ip4_dst_hoplimit(&rt->dst);
 888         }
 889
 890         ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags;
 891         ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ?
 892                                    htons(ETH_P_TEB) : skb->protocol;
 893
 894         if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) {
 895                 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4);
 896
 897                 if (tunnel->parms.o_flags&GRE_SEQ) {
 898                         ++tunnel->o_seqno;
 899                         *ptr = htonl(tunnel->o_seqno);
 900                         ptr--;
 901                 }
 902                 if (tunnel->parms.o_flags&GRE_KEY) {
 903                         *ptr = tunnel->parms.o_key;
 904                         ptr--;
 905                 }
 906                 if (tunnel->parms.o_flags&GRE_CSUM) {
 907                         *ptr = 0;
 908                         *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr));
 909                 }
 910         }
 911
 912         nf_reset(skb);
 913         tstats = this_cpu_ptr(dev->tstats);
 914         __IPTUNNEL_XMIT(tstats, &dev->stats);
 915         return NETDEV_TX_OK;
 916
 917 tx_error_icmp:
 918         dst_link_failure(skb);
 919
 920 tx_error:
 921         dev->stats.tx_errors++;
 922         dev_kfree_skb(skb);
 923         return NETDEV_TX_OK;
 924 }
 925
 926 static int ipgre_tunnel_bind_dev(struct net_device *dev)
 927 {
 928         struct net_device *tdev = NULL;
 929         struct ip_tunnel *tunnel;
 930         struct iphdr *iph;
 931         int hlen = LL_MAX_HEADER;
 932         int mtu = ETH_DATA_LEN;
 933         int addend = sizeof(struct iphdr) + 4;
 934
 935         tunnel = netdev_priv(dev);
 936         iph = &tunnel->parms.iph;
 937
 938         /* Guess output device to choose reasonable mtu and needed_headroom */
 939
 940         if (iph->daddr) {
 941                 struct rtable *rt = ip_route_output_gre(dev_net(dev),
 942                                                         iph->daddr, iph->saddr,
 943                                                         tunnel->parms.o_key,
 944                                                         RT_TOS(iph->tos),
 945                                                         tunnel->parms.link);
 946
 947                 if (!IS_ERR(rt)) {
 948                         tdev = rt->dst.dev;
 949                         ip_rt_put(rt);
 950                 }
 951
 952                 if (dev->type != ARPHRD_ETHER)
 953                         dev->flags |= IFF_POINTOPOINT;
 954         }
 955
 956         if (!tdev && tunnel->parms.link)
 957                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
 958
 959         if (tdev) {
 960                 hlen = tdev->hard_header_len + tdev->needed_headroom;
 961                 mtu = tdev->mtu;
 962         }
 963         dev->iflink = tunnel->parms.link;
 964
 965         /* Precalculate GRE options length */
 966         if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) {
 967                 if (tunnel->parms.o_flags&GRE_CSUM)
 968                         addend += 4;
 969                 if (tunnel->parms.o_flags&GRE_KEY)
 970                         addend += 4;
 971                 if (tunnel->parms.o_flags&GRE_SEQ)
 972                         addend += 4;
 973         }
 974         dev->needed_headroom = addend + hlen;
 975         mtu -= dev->hard_header_len + addend;
 976
 977         if (mtu < 68)
 978                 mtu = 68;
 979
 980         tunnel->hlen = addend;
 981
 982         return mtu;
 983 }
 984
 985 static int
 986 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
 987 {
 988         int err = 0;
 989         struct ip_tunnel_parm p;
 990         struct ip_tunnel *t;
 991         struct net *net = dev_net(dev);
 992         struct ipgre_net *ign = net_generic(net, ipgre_net_id);
 993
 994         switch (cmd) {
 995         case SIOCGETTUNNEL:
 996                 t = NULL;
 997                 if (dev == ign->fb_tunnel_dev) {
 998                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
 999                                 err = -EFAULT;
1000                                 break;
1001                         }
1002                         t = ipgre_tunnel_locate(net, &p, 0);
1003                 }
1004                 if (t == NULL)
1005                         t = netdev_priv(dev);
1006                 memcpy(&p, &t->parms, sizeof(p));
1007                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1008                         err = -EFAULT;
1009                 break;
1010
1011         case SIOCADDTUNNEL:
1012         case SIOCCHGTUNNEL:
1013                 err = -EPERM;
1014                 if (!capable(CAP_NET_ADMIN))
1015                         goto done;
1016
1017                 err = -EFAULT;
1018                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1019                         goto done;
1020
1021                 err = -EINVAL;
1022                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
1023                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) ||
1024                     ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING)))
1025                         goto done;
1026                 if (p.iph.ttl)
1027                         p.iph.frag_off |= htons(IP_DF);
1028
1029                 if (!(p.i_flags&GRE_KEY))
1030                         p.i_key = 0;
1031                 if (!(p.o_flags&GRE_KEY))
1032                         p.o_key = 0;
1033
1034                 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1035
1036                 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1037                         if (t != NULL) {
1038                                 if (t->dev != dev) {
1039                                         err = -EEXIST;
1040                                         break;
1041                                 }
1042                         } else {
1043                                 unsigned int nflags = 0;
1044
1045                                 t = netdev_priv(dev);
1046
1047                                 if (ipv4_is_multicast(p.iph.daddr))
1048                                         nflags = IFF_BROADCAST;
1049                                 else if (p.iph.daddr)
1050                                         nflags = IFF_POINTOPOINT;
1051
1052                                 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
1053                                         err = -EINVAL;
1054                                         break;
1055                                 }
1056                                 ipgre_tunnel_unlink(ign, t);
1057                                 synchronize_net();
1058                                 t->parms.iph.saddr = p.iph.saddr;
1059                                 t->parms.iph.daddr = p.iph.daddr;
1060                                 t->parms.i_key = p.i_key;
1061                                 t->parms.o_key = p.o_key;
1062                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
1063                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
1064                                 ipgre_tunnel_link(ign, t);
1065                                 netdev_state_change(dev);
1066                         }
1067                 }
1068
1069                 if (t) {
1070                         err = 0;
1071                         if (cmd == SIOCCHGTUNNEL) {
1072                                 t->parms.iph.ttl = p.iph.ttl;
1073                                 t->parms.iph.tos = p.iph.tos;
1074                                 t->parms.iph.frag_off = p.iph.frag_off;
1075                                 if (t->parms.link != p.link) {
1076                                         t->parms.link = p.link;
1077                                         dev->mtu = ipgre_tunnel_bind_dev(dev);
1078                                         netdev_state_change(dev);
1079                                 }
1080                         }
1081                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1082                                 err = -EFAULT;
1083                 } else
1084                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1085                 break;
1086
1087         case SIOCDELTUNNEL:
1088                 err = -EPERM;
1089                 if (!capable(CAP_NET_ADMIN))
1090                         goto done;
1091
1092                 if (dev == ign->fb_tunnel_dev) {
1093                         err = -EFAULT;
1094                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1095                                 goto done;
1096                         err = -ENOENT;
1097                         if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL)
1098                                 goto done;
1099                         err = -EPERM;
1100                         if (t == netdev_priv(ign->fb_tunnel_dev))
1101                                 goto done;
1102                         dev = t->dev;
1103                 }
1104                 unregister_netdevice(dev);
1105                 err = 0;
1106                 break;
1107
1108         default:
1109                 err = -EINVAL;
1110         }
1111
1112 done:
1113         return err;
1114 }
1115
1116 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1117 {
1118         struct ip_tunnel *tunnel = netdev_priv(dev);
1119         if (new_mtu < 68 ||
1120             new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen)
1121                 return -EINVAL;
1122         dev->mtu = new_mtu;
1123         return 0;
1124 }
1125
1126 /* Nice toy. Unfortunately, useless in real life :-)
1127    It allows to construct virtual multiprotocol broadcast "LAN"
1128    over the Internet, provided multicast routing is tuned.
1129
1130
1131    I have no idea was this bicycle invented before me,
1132    so that I had to set ARPHRD_IPGRE to a random value.
1133    I have an impression, that Cisco could make something similar,
1134    but this feature is apparently missing in IOS<=11.2(8).
1135
1136    I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
1137    with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
1138
1139    ping -t 255 224.66.66.66
1140
1141    If nobody answers, mbone does not work.
1142
1143    ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
1144    ip addr add 10.66.66.<somewhat>/24 dev Universe
1145    ifconfig Universe up
1146    ifconfig Universe add fe80::<Your_real_addr>/10
1147    ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
1148    ftp 10.66.66.66
1149    ...
1150    ftp fec0:6666:6666::193.233.7.65
1151    ...
1152
1153  */
1154
1155 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
1156                         unsigned short type,
1157                         const void *daddr, const void *saddr, unsigned int len)
1158 {
1159         struct ip_tunnel *t = netdev_priv(dev);
1160         struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen);
1161         __be16 *p = (__be16*)(iph+1);
1162
1163         memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
1164         p[0]            = t->parms.o_flags;
1165         p[1]            = htons(type);
1166
1167         /*
1168          *      Set the source hardware address.
1169          */
1170
1171         if (saddr)
1172                 memcpy(&iph->saddr, saddr, 4);
1173         if (daddr)
1174                 memcpy(&iph->daddr, daddr, 4);
1175         if (iph->daddr)
1176                 return t->hlen;
1177
1178         return -t->hlen;
1179 }
1180
1181 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
1182 {
1183         struct iphdr *iph = (struct iphdr *) skb_mac_header(skb);
1184         memcpy(haddr, &iph->saddr, 4);
1185         return 4;
1186 }
1187
1188 static const struct header_ops ipgre_header_ops = {
1189         .create = ipgre_header,
1190         .parse  = ipgre_header_parse,
1191 };
1192
1193 #ifdef CONFIG_NET_IPGRE_BROADCAST
1194 static int ipgre_open(struct net_device *dev)
1195 {
1196         struct ip_tunnel *t = netdev_priv(dev);
1197
1198         if (ipv4_is_multicast(t->parms.iph.daddr)) {
1199                 struct rtable *rt = ip_route_output_gre(dev_net(dev),
1200                                                         t->parms.iph.daddr,
1201                                                         t->parms.iph.saddr,
1202                                                         t->parms.o_key,
1203                                                         RT_TOS(t->parms.iph.tos),
1204                                                         t->parms.link);
1205
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");