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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14
  15 #include <linux/capability.h>
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/slab.h>
  20 #include <linux/uaccess.h>
  21 #include <linux/skbuff.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/in.h>
  24 #include <linux/tcp.h>
  25 #include <linux/udp.h>
  26 #include <linux/if_arp.h>
  27 #include <linux/if_vlan.h>
  28 #include <linux/init.h>
  29 #include <linux/in6.h>
  30 #include <linux/inetdevice.h>
  31 #include <linux/igmp.h>
  32 #include <linux/netfilter_ipv4.h>
  33 #include <linux/etherdevice.h>
  34 #include <linux/if_ether.h>
  35
  36 #include <net/sock.h>
  37 #include <net/ip.h>
  38 #include <net/icmp.h>
  39 #include <net/protocol.h>
  40 #include <net/ip_tunnels.h>
  41 #include <net/arp.h>
  42 #include <net/checksum.h>
  43 #include <net/dsfield.h>
  44 #include <net/inet_ecn.h>
  45 #include <net/xfrm.h>
  46 #include <net/net_namespace.h>
  47 #include <net/netns/generic.h>
  48 #include <net/rtnetlink.h>
  49 #include <net/gre.h>
  50 #include <net/dst_metadata.h>
  51 #include <net/erspan.h>
  52
  53 /*
  54    Problems & solutions
  55    --------------------
  56
  57    1. The most important issue is detecting local dead loops.
  58    They would cause complete host lockup in transmit, which
  59    would be "resolved" by stack overflow or, if queueing is enabled,
  60    with infinite looping in net_bh.
  61
  62    We cannot track such dead loops during route installation,
  63    it is infeasible task. The most general solutions would be
  64    to keep skb->encapsulation counter (sort of local ttl),
  65    and silently drop packet when it expires. It is a good
  66    solution, but it supposes maintaining new variable in ALL
  67    skb, even if no tunneling is used.
  68
  69    Current solution: xmit_recursion breaks dead loops. This is a percpu
  70    counter, since when we enter the first ndo_xmit(), cpu migration is
  71    forbidden. We force an exit if this counter reaches RECURSION_LIMIT
  72
  73    2. Networking dead loops would not kill routers, but would really
  74    kill network. IP hop limit plays role of "t->recursion" in this case,
  75    if we copy it from packet being encapsulated to upper header.
  76    It is very good solution, but it introduces two problems:
  77
  78    - Routing protocols, using packets with ttl=1 (OSPF, RIP2),
  79      do not work over tunnels.
  80    - traceroute does not work. I planned to relay ICMP from tunnel,
  81      so that this problem would be solved and traceroute output
  82      would even more informative. This idea appeared to be wrong:
  83      only Linux complies to rfc1812 now (yes, guys, Linux is the only
  84      true router now :-)), all routers (at least, in neighbourhood of mine)
  85      return only 8 bytes of payload. It is the end.
  86
  87    Hence, if we want that OSPF worked or traceroute said something reasonable,
  88    we should search for another solution.
  89
  90    One of them is to parse packet trying to detect inner encapsulation
  91    made by our node. It is difficult or even impossible, especially,
  92    taking into account fragmentation. TO be short, ttl is not solution at all.
  93
  94    Current solution: The solution was UNEXPECTEDLY SIMPLE.
  95    We force DF flag on tunnels with preconfigured hop limit,
  96    that is ALL. :-) Well, it does not remove the problem completely,
  97    but exponential growth of network traffic is changed to linear
  98    (branches, that exceed pmtu are pruned) and tunnel mtu
  99    rapidly degrades to value <68, where looping stops.
 100    Yes, it is not good if there exists a router in the loop,
 101    which does not force DF, even when encapsulating packets have DF set.
 102    But it is not our problem! Nobody could accuse us, we made
 103    all that we could make. Even if it is your gated who injected
 104    fatal route to network, even if it were you who configured
 105    fatal static route: you are innocent. :-)
 106
 107    Alexey Kuznetsov.
 108  */
 109
 110 static bool log_ecn_error = true;
 111 module_param(log_ecn_error, bool, 0644);
 112 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
 113
 114 static struct rtnl_link_ops ipgre_link_ops __read_mostly;
 115 static int ipgre_tunnel_init(struct net_device *dev);
 116 static void erspan_build_header(struct sk_buff *skb,
 117                                 u32 id, u32 index,
 118                                 bool truncate, bool is_ipv4);
 119
 120 static unsigned int ipgre_net_id __read_mostly;
 121 static unsigned int gre_tap_net_id __read_mostly;
 122 static unsigned int erspan_net_id __read_mostly;
 123
 124 static int ipgre_err(struct sk_buff *skb, u32 info,
 125                      const struct tnl_ptk_info *tpi)
 126 {
 127
 128         /* All the routers (except for Linux) return only
 129            8 bytes of packet payload. It means, that precise relaying of
 130            ICMP in the real Internet is absolutely infeasible.
 131
 132            Moreover, Cisco "wise men" put GRE key to the third word
 133            in GRE header. It makes impossible maintaining even soft
 134            state for keyed GRE tunnels with enabled checksum. Tell
 135            them "thank you".
 136
 137            Well, I wonder, rfc1812 was written by Cisco employee,
 138            what the hell these idiots break standards established
 139            by themselves???
 140            */
 141         struct net *net = dev_net(skb->dev);
 142         struct ip_tunnel_net *itn;
 143         const struct iphdr *iph;
 144         const int type = icmp_hdr(skb)->type;
 145         const int code = icmp_hdr(skb)->code;
 146         unsigned int data_len = 0;
 147         struct ip_tunnel *t;
 148
 149         if (tpi->proto == htons(ETH_P_TEB))
 150                 itn = net_generic(net, gre_tap_net_id);
 151         else if (tpi->proto == htons(ETH_P_ERSPAN) ||
 152                  tpi->proto == htons(ETH_P_ERSPAN2))
 153                 itn = net_generic(net, erspan_net_id);
 154         else
 155                 itn = net_generic(net, ipgre_net_id);
 156
 157         iph = (const struct iphdr *)(icmp_hdr(skb) + 1);
 158         t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
 159                              iph->daddr, iph->saddr, tpi->key);
 160
 161         if (!t)
 162                 return -ENOENT;
 163
 164         switch (type) {
 165         default:
 166         case ICMP_PARAMETERPROB:
 167                 return 0;
 168
 169         case ICMP_DEST_UNREACH:
 170                 switch (code) {
 171                 case ICMP_SR_FAILED:
 172                 case ICMP_PORT_UNREACH:
 173                         /* Impossible event. */
 174                         return 0;
 175                 default:
 176                         /* All others are translated to HOST_UNREACH.
 177                            rfc2003 contains "deep thoughts" about NET_UNREACH,
 178                            I believe they are just ether pollution. --ANK
 179                          */
 180                         break;
 181                 }
 182                 break;
 183
 184         case ICMP_TIME_EXCEEDED:
 185                 if (code != ICMP_EXC_TTL)
 186                         return 0;
 187                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
 188                 break;
 189
 190         case ICMP_REDIRECT:
 191                 break;
 192         }
 193
 194 #if IS_ENABLED(CONFIG_IPV6)
 195        if (tpi->proto == htons(ETH_P_IPV6) &&
 196            !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len,
 197                                        type, data_len))
 198                return 0;
 199 #endif
 200
 201         if (t->parms.iph.daddr == 0 ||
 202             ipv4_is_multicast(t->parms.iph.daddr))
 203                 return 0;
 204
 205         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
 206                 return 0;
 207
 208         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
 209                 t->err_count++;
 210         else
 211                 t->err_count = 1;
 212         t->err_time = jiffies;
 213
 214         return 0;
 215 }
 216
 217 static void gre_err(struct sk_buff *skb, u32 info)
 218 {
 219         /* All the routers (except for Linux) return only
 220          * 8 bytes of packet payload. It means, that precise relaying of
 221          * ICMP in the real Internet is absolutely infeasible.
 222          *
 223          * Moreover, Cisco "wise men" put GRE key to the third word
 224          * in GRE header. It makes impossible maintaining even soft
 225          * state for keyed
 226          * GRE tunnels with enabled checksum. Tell them "thank you".
 227          *
 228          * Well, I wonder, rfc1812 was written by Cisco employee,
 229          * what the hell these idiots break standards established
 230          * by themselves???
 231          */
 232
 233         const struct iphdr *iph = (struct iphdr *)skb->data;
 234         const int type = icmp_hdr(skb)->type;
 235         const int code = icmp_hdr(skb)->code;
 236         struct tnl_ptk_info tpi;
 237
 238         if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IP),
 239                              iph->ihl * 4) < 0)
 240                 return;
 241
 242         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
 243                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
 244                                  skb->dev->ifindex, IPPROTO_GRE);
 245                 return;
 246         }
 247         if (type == ICMP_REDIRECT) {
 248                 ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex,
 249                               IPPROTO_GRE);
 250                 return;
 251         }
 252
 253         ipgre_err(skb, info, &tpi);
 254 }
 255
 256 static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi,
 257                       int gre_hdr_len)
 258 {
 259         struct net *net = dev_net(skb->dev);
 260         struct metadata_dst *tun_dst = NULL;
 261         struct erspan_base_hdr *ershdr;
 262         struct erspan_metadata *pkt_md;
 263         struct ip_tunnel_net *itn;
 264         struct ip_tunnel *tunnel;
 265         const struct iphdr *iph;
 266         struct erspan_md2 *md2;
 267         int ver;
 268         int len;
 269
 270         itn = net_generic(net, erspan_net_id);
 271         len = gre_hdr_len + sizeof(*ershdr);
 272
 273         /* Check based hdr len */
 274         if (unlikely(!pskb_may_pull(skb, len)))
 275                 return PACKET_REJECT;
 276
 277         iph = ip_hdr(skb);
 278         ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
 279         ver = ershdr->ver;
 280
 281         /* The original GRE header does not have key field,
 282          * Use ERSPAN 10-bit session ID as key.
 283          */
 284         tpi->key = cpu_to_be32(get_session_id(ershdr));
 285         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex,
 286                                   tpi->flags | TUNNEL_KEY,
 287                                   iph->saddr, iph->daddr, tpi->key);
 288
 289         if (tunnel) {
 290                 len = gre_hdr_len + erspan_hdr_len(ver);
 291                 if (unlikely(!pskb_may_pull(skb, len)))
 292                         return PACKET_REJECT;
 293
 294                 ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len);
 295                 pkt_md = (struct erspan_metadata *)(ershdr + 1);
 296
 297                 if (__iptunnel_pull_header(skb,
 298                                            len,
 299                                            htons(ETH_P_TEB),
 300                                            false, false) < 0)
 301                         goto drop;
 302
 303                 if (tunnel->collect_md) {
 304                         struct ip_tunnel_info *info;
 305                         struct erspan_metadata *md;
 306                         __be64 tun_id;
 307                         __be16 flags;
 308
 309                         tpi->flags |= TUNNEL_KEY;
 310                         flags = tpi->flags;
 311                         tun_id = key32_to_tunnel_id(tpi->key);
 312
 313                         tun_dst = ip_tun_rx_dst(skb, flags,
 314                                                 tun_id, sizeof(*md));
 315                         if (!tun_dst)
 316                                 return PACKET_REJECT;
 317
 318                         md = ip_tunnel_info_opts(&tun_dst->u.tun_info);
 319                         md->version = ver;
 320                         md2 = &md->u.md2;
 321                         memcpy(md2, pkt_md, ver == 1 ? ERSPAN_V1_MDSIZE :
 322                                                        ERSPAN_V2_MDSIZE);
 323
 324                         info = &tun_dst->u.tun_info;
 325                         info->key.tun_flags |= TUNNEL_ERSPAN_OPT;
 326                         info->options_len = sizeof(*md);
 327                 }
 328
 329                 skb_reset_mac_header(skb);
 330                 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
 331                 return PACKET_RCVD;
 332         }
 333         return PACKET_REJECT;
 334
 335 drop:
 336         kfree_skb(skb);
 337         return PACKET_RCVD;
 338 }
 339
 340 static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 341                        struct ip_tunnel_net *itn, int hdr_len, bool raw_proto)
 342 {
 343         struct metadata_dst *tun_dst = NULL;
 344         const struct iphdr *iph;
 345         struct ip_tunnel *tunnel;
 346
 347         iph = ip_hdr(skb);
 348         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags,
 349                                   iph->saddr, iph->daddr, tpi->key);
 350
 351         if (tunnel) {
 352                 if (__iptunnel_pull_header(skb, hdr_len, tpi->proto,
 353                                            raw_proto, false) < 0)
 354                         goto drop;
 355
 356                 if (tunnel->dev->type != ARPHRD_NONE)
 357                         skb_pop_mac_header(skb);
 358                 else
 359                         skb_reset_mac_header(skb);
 360                 if (tunnel->collect_md) {
 361                         __be16 flags;
 362                         __be64 tun_id;
 363
 364                         flags = tpi->flags & (TUNNEL_CSUM | TUNNEL_KEY);
 365                         tun_id = key32_to_tunnel_id(tpi->key);
 366                         tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0);
 367                         if (!tun_dst)
 368                                 return PACKET_REJECT;
 369                 }
 370
 371                 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error);
 372                 return PACKET_RCVD;
 373         }
 374         return PACKET_NEXT;
 375
 376 drop:
 377         kfree_skb(skb);
 378         return PACKET_RCVD;
 379 }
 380
 381 static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi,
 382                      int hdr_len)
 383 {
 384         struct net *net = dev_net(skb->dev);
 385         struct ip_tunnel_net *itn;
 386         int res;
 387
 388         if (tpi->proto == htons(ETH_P_TEB))
 389                 itn = net_generic(net, gre_tap_net_id);
 390         else
 391                 itn = net_generic(net, ipgre_net_id);
 392
 393         res = __ipgre_rcv(skb, tpi, itn, hdr_len, false);
 394         if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) {
 395                 /* ipgre tunnels in collect metadata mode should receive
 396                  * also ETH_P_TEB traffic.
 397                  */
 398                 itn = net_generic(net, ipgre_net_id);
 399                 res = __ipgre_rcv(skb, tpi, itn, hdr_len, true);
 400         }
 401         return res;
 402 }
 403
 404 static int gre_rcv(struct sk_buff *skb)
 405 {
 406         struct tnl_ptk_info tpi;
 407         bool csum_err = false;
 408         int hdr_len;
 409
 410 #ifdef CONFIG_NET_IPGRE_BROADCAST
 411         if (ipv4_is_multicast(ip_hdr(skb)->daddr)) {
 412                 /* Looped back packet, drop it! */
 413                 if (rt_is_output_route(skb_rtable(skb)))
 414                         goto drop;
 415         }
 416 #endif
 417
 418         hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0);
 419         if (hdr_len < 0)
 420                 goto drop;
 421
 422         if (unlikely(tpi.proto == htons(ETH_P_ERSPAN) ||
 423                      tpi.proto == htons(ETH_P_ERSPAN2))) {
 424                 if (erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
 425                         return 0;
 426                 goto out;
 427         }
 428
 429         if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD)
 430                 return 0;
 431
 432 out:
 433         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
 434 drop:
 435         kfree_skb(skb);
 436         return 0;
 437 }
 438
 439 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev,
 440                        const struct iphdr *tnl_params,
 441                        __be16 proto)
 442 {
 443         struct ip_tunnel *tunnel = netdev_priv(dev);
 444
 445         if (tunnel->parms.o_flags & TUNNEL_SEQ)
 446                 tunnel->o_seqno++;
 447
 448         /* Push GRE header. */
 449         gre_build_header(skb, tunnel->tun_hlen,
 450                          tunnel->parms.o_flags, proto, tunnel->parms.o_key,
 451                          htonl(tunnel->o_seqno));
 452
 453         ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol);
 454 }
 455
 456 static int gre_handle_offloads(struct sk_buff *skb, bool csum)
 457 {
 458         return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE);
 459 }
 460
 461 static struct rtable *gre_get_rt(struct sk_buff *skb,
 462                                  struct net_device *dev,
 463                                  struct flowi4 *fl,
 464                                  const struct ip_tunnel_key *key)
 465 {
 466         struct net *net = dev_net(dev);
 467
 468         memset(fl, 0, sizeof(*fl));
 469         fl->daddr = key->u.ipv4.dst;
 470         fl->saddr = key->u.ipv4.src;
 471         fl->flowi4_tos = RT_TOS(key->tos);
 472         fl->flowi4_mark = skb->mark;
 473         fl->flowi4_proto = IPPROTO_GRE;
 474
 475         return ip_route_output_key(net, fl);
 476 }
 477
 478 static struct rtable *prepare_fb_xmit(struct sk_buff *skb,
 479                                       struct net_device *dev,
 480                                       struct flowi4 *fl,
 481                                       int tunnel_hlen)
 482 {
 483         struct ip_tunnel_info *tun_info;
 484         const struct ip_tunnel_key *key;
 485         struct rtable *rt = NULL;
 486         int min_headroom;
 487         bool use_cache;
 488         int err;
 489
 490         tun_info = skb_tunnel_info(skb);
 491         key = &tun_info->key;
 492         use_cache = ip_tunnel_dst_cache_usable(skb, tun_info);
 493
 494         if (use_cache)
 495                 rt = dst_cache_get_ip4(&tun_info->dst_cache, &fl->saddr);
 496         if (!rt) {
 497                 rt = gre_get_rt(skb, dev, fl, key);
 498                 if (IS_ERR(rt))
 499                         goto err_free_skb;
 500                 if (use_cache)
 501                         dst_cache_set_ip4(&tun_info->dst_cache, &rt->dst,
 502                                           fl->saddr);
 503         }
 504
 505         min_headroom = LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len
 506                         + tunnel_hlen + sizeof(struct iphdr);
 507         if (skb_headroom(skb) < min_headroom || skb_header_cloned(skb)) {
 508                 int head_delta = SKB_DATA_ALIGN(min_headroom -
 509                                                 skb_headroom(skb) +
 510                                                 16);
 511                 err = pskb_expand_head(skb, max_t(int, head_delta, 0),
 512                                        0, GFP_ATOMIC);
 513                 if (unlikely(err))
 514                         goto err_free_rt;
 515         }
 516         return rt;
 517
 518 err_free_rt:
 519         ip_rt_put(rt);
 520 err_free_skb:
 521         kfree_skb(skb);
 522         dev->stats.tx_dropped++;
 523         return NULL;
 524 }
 525
 526 static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 527                         __be16 proto)
 528 {
 529         struct ip_tunnel *tunnel = netdev_priv(dev);
 530         struct ip_tunnel_info *tun_info;
 531         const struct ip_tunnel_key *key;
 532         struct rtable *rt = NULL;
 533         struct flowi4 fl;
 534         int tunnel_hlen;
 535         __be16 df, flags;
 536
 537         tun_info = skb_tunnel_info(skb);
 538         if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
 539                      ip_tunnel_info_af(tun_info) != AF_INET))
 540                 goto err_free_skb;
 541
 542         key = &tun_info->key;
 543         tunnel_hlen = gre_calc_hlen(key->tun_flags);
 544
 545         rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
 546         if (!rt)
 547                 return;
 548
 549         /* Push Tunnel header. */
 550         if (gre_handle_offloads(skb, !!(tun_info->key.tun_flags & TUNNEL_CSUM)))
 551                 goto err_free_rt;
 552
 553         flags = tun_info->key.tun_flags &
 554                 (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
 555         gre_build_header(skb, tunnel_hlen, flags, proto,
 556                          tunnel_id_to_key32(tun_info->key.tun_id),
 557                          (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
 558
 559         df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
 560
 561         iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
 562                       key->tos, key->ttl, df, false);
 563         return;
 564
 565 err_free_rt:
 566         ip_rt_put(rt);
 567 err_free_skb:
 568         kfree_skb(skb);
 569         dev->stats.tx_dropped++;
 570 }
 571
 572 static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev,
 573                            __be16 proto)
 574 {
 575         struct ip_tunnel *tunnel = netdev_priv(dev);
 576         struct ip_tunnel_info *tun_info;
 577         const struct ip_tunnel_key *key;
 578         struct erspan_metadata *md;
 579         struct rtable *rt = NULL;
 580         bool truncate = false;
 581         struct flowi4 fl;
 582         int tunnel_hlen;
 583         int version;
 584         __be16 df;
 585         int nhoff;
 586         int thoff;
 587
 588         tun_info = skb_tunnel_info(skb);
 589         if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) ||
 590                      ip_tunnel_info_af(tun_info) != AF_INET))
 591                 goto err_free_skb;
 592
 593         key = &tun_info->key;
 594         if (!(tun_info->key.tun_flags & TUNNEL_ERSPAN_OPT))
 595                 goto err_free_rt;
 596         md = ip_tunnel_info_opts(tun_info);
 597         if (!md)
 598                 goto err_free_rt;
 599
 600         /* ERSPAN has fixed 8 byte GRE header */
 601         version = md->version;
 602         tunnel_hlen = 8 + erspan_hdr_len(version);
 603
 604         rt = prepare_fb_xmit(skb, dev, &fl, tunnel_hlen);
 605         if (!rt)
 606                 return;
 607
 608         if (gre_handle_offloads(skb, false))
 609                 goto err_free_rt;
 610
 611         if (skb->len > dev->mtu + dev->hard_header_len) {
 612                 pskb_trim(skb, dev->mtu + dev->hard_header_len);
 613                 truncate = true;
 614         }
 615
 616         nhoff = skb_network_header(skb) - skb_mac_header(skb);
 617         if (skb->protocol == htons(ETH_P_IP) &&
 618             (ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff))
 619                 truncate = true;
 620
 621         thoff = skb_transport_header(skb) - skb_mac_header(skb);
 622         if (skb->protocol == htons(ETH_P_IPV6) &&
 623             (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff))
 624                 truncate = true;
 625
 626         if (version == 1) {
 627                 erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)),
 628                                     ntohl(md->u.index), truncate, true);
 629         } else if (version == 2) {
 630                 erspan_build_header_v2(skb,
 631                                        ntohl(tunnel_id_to_key32(key->tun_id)),
 632                                        md->u.md2.dir,
 633                                        get_hwid(&md->u.md2),
 634                                        truncate, true);
 635         } else {
 636                 goto err_free_rt;
 637         }
 638
 639         gre_build_header(skb, 8, TUNNEL_SEQ,
 640                          htons(ETH_P_ERSPAN), 0, htonl(tunnel->o_seqno++));
 641
 642         df = key->tun_flags & TUNNEL_DONT_FRAGMENT ?  htons(IP_DF) : 0;
 643
 644         iptunnel_xmit(skb->sk, rt, skb, fl.saddr, key->u.ipv4.dst, IPPROTO_GRE,
 645                       key->tos, key->ttl, df, false);
 646         return;
 647
 648 err_free_rt:
 649         ip_rt_put(rt);
 650 err_free_skb:
 651         kfree_skb(skb);
 652         dev->stats.tx_dropped++;
 653 }
 654
 655 static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb)
 656 {
 657         struct ip_tunnel_info *info = skb_tunnel_info(skb);
 658         struct rtable *rt;
 659         struct flowi4 fl4;
 660
 661         if (ip_tunnel_info_af(info) != AF_INET)
 662                 return -EINVAL;
 663
 664         rt = gre_get_rt(skb, dev, &fl4, &info->key);
 665         if (IS_ERR(rt))
 666                 return PTR_ERR(rt);
 667
 668         ip_rt_put(rt);
 669         info->key.u.ipv4.src = fl4.saddr;
 670         return 0;
 671 }
 672
 673 static netdev_tx_t ipgre_xmit(struct sk_buff *skb,
 674                               struct net_device *dev)
 675 {
 676         struct ip_tunnel *tunnel = netdev_priv(dev);
 677         const struct iphdr *tnl_params;
 678
 679         if (!pskb_inet_may_pull(skb))
 680                 goto free_skb;
 681
 682         if (tunnel->collect_md) {
 683                 gre_fb_xmit(skb, dev, skb->protocol);
 684                 return NETDEV_TX_OK;
 685         }
 686
 687         if (dev->header_ops) {
 688                 /* Need space for new headers */
 689                 if (skb_cow_head(skb, dev->needed_headroom -
 690                                       (tunnel->hlen + sizeof(struct iphdr))))
 691                         goto free_skb;
 692
 693                 tnl_params = (const struct iphdr *)skb->data;
 694
 695                 /* Pull skb since ip_tunnel_xmit() needs skb->data pointing
 696                  * to gre header.
 697                  */
 698                 skb_pull(skb, tunnel->hlen + sizeof(struct iphdr));
 699                 skb_reset_mac_header(skb);
 700         } else {
 701                 if (skb_cow_head(skb, dev->needed_headroom))
 702                         goto free_skb;
 703
 704                 tnl_params = &tunnel->parms.iph;
 705         }
 706
 707         if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
 708                 goto free_skb;
 709
 710         __gre_xmit(skb, dev, tnl_params, skb->protocol);
 711         return NETDEV_TX_OK;
 712
 713 free_skb:
 714         kfree_skb(skb);
 715         dev->stats.tx_dropped++;
 716         return NETDEV_TX_OK;
 717 }
 718
 719 static netdev_tx_t erspan_xmit(struct sk_buff *skb,
 720                                struct net_device *dev)
 721 {
 722         struct ip_tunnel *tunnel = netdev_priv(dev);
 723         bool truncate = false;
 724
 725         if (!pskb_inet_may_pull(skb))
 726                 goto free_skb;
 727
 728         if (tunnel->collect_md) {
 729                 erspan_fb_xmit(skb, dev, skb->protocol);
 730                 return NETDEV_TX_OK;
 731         }
 732
 733         if (gre_handle_offloads(skb, false))
 734                 goto free_skb;
 735
 736         if (skb_cow_head(skb, dev->needed_headroom))
 737                 goto free_skb;
 738
 739         if (skb->len > dev->mtu + dev->hard_header_len) {
 740                 pskb_trim(skb, dev->mtu + dev->hard_header_len);
 741                 truncate = true;
 742         }
 743
 744         /* Push ERSPAN header */
 745         if (tunnel->erspan_ver == 1)
 746                 erspan_build_header(skb, ntohl(tunnel->parms.o_key),
 747                                     tunnel->index,
 748                                     truncate, true);
 749         else if (tunnel->erspan_ver == 2)
 750                 erspan_build_header_v2(skb, ntohl(tunnel->parms.o_key),
 751                                        tunnel->dir, tunnel->hwid,
 752                                        truncate, true);
 753         else
 754                 goto free_skb;
 755
 756         tunnel->parms.o_flags &= ~TUNNEL_KEY;
 757         __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_ERSPAN));
 758         return NETDEV_TX_OK;
 759
 760 free_skb:
 761         kfree_skb(skb);
 762         dev->stats.tx_dropped++;
 763         return NETDEV_TX_OK;
 764 }
 765
 766 static netdev_tx_t gre_tap_xmit(struct sk_buff *skb,
 767                                 struct net_device *dev)
 768 {
 769         struct ip_tunnel *tunnel = netdev_priv(dev);
 770
 771         if (!pskb_inet_may_pull(skb))
 772                 goto free_skb;
 773
 774         if (tunnel->collect_md) {
 775                 gre_fb_xmit(skb, dev, htons(ETH_P_TEB));
 776                 return NETDEV_TX_OK;
 777         }
 778
 779         if (gre_handle_offloads(skb, !!(tunnel->parms.o_flags & TUNNEL_CSUM)))
 780                 goto free_skb;
 781
 782         if (skb_cow_head(skb, dev->needed_headroom))
 783                 goto free_skb;
 784
 785         __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB));
 786         return NETDEV_TX_OK;
 787
 788 free_skb:
 789         kfree_skb(skb);
 790         dev->stats.tx_dropped++;
 791         return NETDEV_TX_OK;
 792 }
 793
 794 static void ipgre_link_update(struct net_device *dev, bool set_mtu)
 795 {
 796         struct ip_tunnel *tunnel = netdev_priv(dev);
 797         int len;
 798
 799         len = tunnel->tun_hlen;
 800         tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
 801         len = tunnel->tun_hlen - len;
 802         tunnel->hlen = tunnel->hlen + len;
 803
 804         dev->needed_headroom = dev->needed_headroom + len;
 805         if (set_mtu)
 806                 dev->mtu = max_t(int, dev->mtu - len, 68);
 807
 808         if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
 809                 if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
 810                     tunnel->encap.type == TUNNEL_ENCAP_NONE) {
 811                         dev->features |= NETIF_F_GSO_SOFTWARE;
 812                         dev->hw_features |= NETIF_F_GSO_SOFTWARE;
 813                 } else {
 814                         dev->features &= ~NETIF_F_GSO_SOFTWARE;
 815                         dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
 816                 }
 817                 dev->features |= NETIF_F_LLTX;
 818         } else {
 819                 dev->hw_features &= ~NETIF_F_GSO_SOFTWARE;
 820                 dev->features &= ~(NETIF_F_LLTX | NETIF_F_GSO_SOFTWARE);
 821         }
 822 }
 823
 824 static int ipgre_tunnel_ioctl(struct net_device *dev,
 825                               struct ifreq *ifr, int cmd)
 826 {
 827         struct ip_tunnel_parm p;
 828         int err;
 829
 830         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 831                 return -EFAULT;
 832
 833         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 834                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
 835                     p.iph.ihl != 5 || (p.iph.frag_off & htons(~IP_DF)) ||
 836                     ((p.i_flags | p.o_flags) & (GRE_VERSION | GRE_ROUTING)))
 837                         return -EINVAL;
 838         }
 839
 840         p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
 841         p.o_flags = gre_flags_to_tnl_flags(p.o_flags);
 842
 843         err = ip_tunnel_ioctl(dev, &p, cmd);
 844         if (err)
 845                 return err;
 846
 847         if (cmd == SIOCCHGTUNNEL) {
 848                 struct ip_tunnel *t = netdev_priv(dev);
 849
 850                 t->parms.i_flags = p.i_flags;
 851                 t->parms.o_flags = p.o_flags;
 852
 853                 if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
 854                         ipgre_link_update(dev, true);
 855         }
 856
 857         p.i_flags = gre_tnl_flags_to_gre_flags(p.i_flags);
 858         p.o_flags = gre_tnl_flags_to_gre_flags(p.o_flags);
 859
 860         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 861                 return -EFAULT;
 862
 863         return 0;
 864 }
 865
 866 /* Nice toy. Unfortunately, useless in real life :-)
 867    It allows to construct virtual multiprotocol broadcast "LAN"
 868    over the Internet, provided multicast routing is tuned.
 869
 870
 871    I have no idea was this bicycle invented before me,
 872    so that I had to set ARPHRD_IPGRE to a random value.
 873    I have an impression, that Cisco could make something similar,
 874    but this feature is apparently missing in IOS<=11.2(8).
 875
 876    I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
 877    with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
 878
 879    ping -t 255 224.66.66.66
 880
 881    If nobody answers, mbone does not work.
 882
 883    ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
 884    ip addr add 10.66.66.<somewhat>/24 dev Universe
 885    ifconfig Universe up
 886    ifconfig Universe add fe80::<Your_real_addr>/10
 887    ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
 888    ftp 10.66.66.66
 889    ...
 890    ftp fec0:6666:6666::193.233.7.65
 891    ...
 892  */
 893 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
 894                         unsigned short type,
 895                         const void *daddr, const void *saddr, unsigned int len)
 896 {
 897         struct ip_tunnel *t = netdev_priv(dev);
 898         struct iphdr *iph;
 899         struct gre_base_hdr *greh;
 900
 901         iph = skb_push(skb, t->hlen + sizeof(*iph));
 902         greh = (struct gre_base_hdr *)(iph+1);
 903         greh->flags = gre_tnl_flags_to_gre_flags(t->parms.o_flags);
 904         greh->protocol = htons(type);
 905
 906         memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
 907
 908         /* Set the source hardware address. */
 909         if (saddr)
 910                 memcpy(&iph->saddr, saddr, 4);
 911         if (daddr)
 912                 memcpy(&iph->daddr, daddr, 4);
 913         if (iph->daddr)
 914                 return t->hlen + sizeof(*iph);
 915
 916         return -(t->hlen + sizeof(*iph));
 917 }
 918
 919 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
 920 {
 921         const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
 922         memcpy(haddr, &iph->saddr, 4);
 923         return 4;
 924 }
 925
 926 static const struct header_ops ipgre_header_ops = {
 927         .create = ipgre_header,
 928         .parse  = ipgre_header_parse,
 929 };
 930
 931 #ifdef CONFIG_NET_IPGRE_BROADCAST
 932 static int ipgre_open(struct net_device *dev)
 933 {
 934         struct ip_tunnel *t = netdev_priv(dev);
 935
 936         if (ipv4_is_multicast(t->parms.iph.daddr)) {
 937                 struct flowi4 fl4;
 938                 struct rtable *rt;
 939
 940                 rt = ip_route_output_gre(t->net, &fl4,
 941                                          t->parms.iph.daddr,
 942                                          t->parms.iph.saddr,
 943                                          t->parms.o_key,
 944                                          RT_TOS(t->parms.iph.tos),
 945                                          t->parms.link);
 946                 if (IS_ERR(rt))
 947                         return -EADDRNOTAVAIL;
 948                 dev = rt->dst.dev;
 949                 ip_rt_put(rt);
 950                 if (!__in_dev_get_rtnl(dev))
 951                         return -EADDRNOTAVAIL;
 952                 t->mlink = dev->ifindex;
 953                 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
 954         }
 955         return 0;
 956 }
 957
 958 static int ipgre_close(struct net_device *dev)
 959 {
 960         struct ip_tunnel *t = netdev_priv(dev);
 961
 962         if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
 963                 struct in_device *in_dev;
 964                 in_dev = inetdev_by_index(t->net, t->mlink);
 965                 if (in_dev)
 966                         ip_mc_dec_group(in_dev, t->parms.iph.daddr);
 967         }
 968         return 0;
 969 }
 970 #endif
 971
 972 static const struct net_device_ops ipgre_netdev_ops = {
 973         .ndo_init               = ipgre_tunnel_init,
 974         .ndo_uninit             = ip_tunnel_uninit,
 975 #ifdef CONFIG_NET_IPGRE_BROADCAST
 976         .ndo_open               = ipgre_open,
 977         .ndo_stop               = ipgre_close,
 978 #endif
 979         .ndo_start_xmit         = ipgre_xmit,
 980         .ndo_do_ioctl           = ipgre_tunnel_ioctl,
 981         .ndo_change_mtu         = ip_tunnel_change_mtu,
 982         .ndo_get_stats64        = ip_tunnel_get_stats64,
 983         .ndo_get_iflink         = ip_tunnel_get_iflink,
 984 };
 985
 986 #define GRE_FEATURES (NETIF_F_SG |              \
 987                       NETIF_F_FRAGLIST |        \
 988                       NETIF_F_HIGHDMA |         \
 989                       NETIF_F_HW_CSUM)
 990
 991 static void ipgre_tunnel_setup(struct net_device *dev)
 992 {
 993         dev->netdev_ops         = &ipgre_netdev_ops;
 994         dev->type               = ARPHRD_IPGRE;
 995         ip_tunnel_setup(dev, ipgre_net_id);
 996 }
 997
 998 static void __gre_tunnel_init(struct net_device *dev)
 999 {
1000         struct ip_tunnel *tunnel;
1001
1002         tunnel = netdev_priv(dev);
1003         tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
1004         tunnel->parms.iph.protocol = IPPROTO_GRE;
1005
1006         tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
1007
1008         dev->features           |= GRE_FEATURES;
1009         dev->hw_features        |= GRE_FEATURES;
1010
1011         if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
1012                 /* TCP offload with GRE SEQ is not supported, nor
1013                  * can we support 2 levels of outer headers requiring
1014                  * an update.
1015                  */
1016                 if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
1017                     (tunnel->encap.type == TUNNEL_ENCAP_NONE)) {
1018                         dev->features    |= NETIF_F_GSO_SOFTWARE;
1019                         dev->hw_features |= NETIF_F_GSO_SOFTWARE;
1020                 }
1021
1022                 /* Can use a lockless transmit, unless we generate
1023                  * output sequences
1024                  */
1025                 dev->features |= NETIF_F_LLTX;
1026         }
1027 }
1028
1029 static int ipgre_tunnel_init(struct net_device *dev)
1030 {
1031         struct ip_tunnel *tunnel = netdev_priv(dev);
1032         struct iphdr *iph = &tunnel->parms.iph;
1033
1034         __gre_tunnel_init(dev);
1035
1036         memcpy(dev->dev_addr, &iph->saddr, 4);
1037         memcpy(dev->broadcast, &iph->daddr, 4);
1038
1039         dev->flags              = IFF_NOARP;
1040         netif_keep_dst(dev);
1041         dev->addr_len           = 4;
1042
1043         if (iph->daddr && !tunnel->collect_md) {
1044 #ifdef CONFIG_NET_IPGRE_BROADCAST
1045                 if (ipv4_is_multicast(iph->daddr)) {
1046                         if (!iph->saddr)
1047                                 return -EINVAL;
1048                         dev->flags = IFF_BROADCAST;
1049                         dev->header_ops = &ipgre_header_ops;
1050                 }
1051 #endif
1052         } else if (!tunnel->collect_md) {
1053                 dev->header_ops = &ipgre_header_ops;
1054         }
1055
1056         return ip_tunnel_init(dev);
1057 }
1058
1059 static const struct gre_protocol ipgre_protocol = {
1060         .handler     = gre_rcv,
1061         .err_handler = gre_err,
1062 };
1063
1064 static int __net_init ipgre_init_net(struct net *net)
1065 {
1066         return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL);
1067 }
1068
1069 static void __net_exit ipgre_exit_batch_net(struct list_head *list_net)
1070 {
1071         ip_tunnel_delete_nets(list_net, ipgre_net_id, &ipgre_link_ops);
1072 }
1073
1074 static struct pernet_operations ipgre_net_ops = {
1075         .init = ipgre_init_net,
1076         .exit_batch = ipgre_exit_batch_net,
1077         .id   = &ipgre_net_id,
1078         .size = sizeof(struct ip_tunnel_net),
1079 };
1080
1081 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
1082                                  struct netlink_ext_ack *extack)
1083 {
1084         __be16 flags;
1085
1086         if (!data)
1087                 return 0;
1088
1089         flags = 0;
1090         if (data[IFLA_GRE_IFLAGS])
1091                 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1092         if (data[IFLA_GRE_OFLAGS])
1093                 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1094         if (flags & (GRE_VERSION|GRE_ROUTING))
1095                 return -EINVAL;
1096
1097         if (data[IFLA_GRE_COLLECT_METADATA] &&
1098             data[IFLA_GRE_ENCAP_TYPE] &&
1099             nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE)
1100                 return -EINVAL;
1101
1102         return 0;
1103 }
1104
1105 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[],
1106                               struct netlink_ext_ack *extack)
1107 {
1108         __be32 daddr;
1109
1110         if (tb[IFLA_ADDRESS]) {
1111                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1112                         return -EINVAL;
1113                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1114                         return -EADDRNOTAVAIL;
1115         }
1116
1117         if (!data)
1118                 goto out;
1119
1120         if (data[IFLA_GRE_REMOTE]) {
1121                 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1122                 if (!daddr)
1123                         return -EINVAL;
1124         }
1125
1126 out:
1127         return ipgre_tunnel_validate(tb, data, extack);
1128 }
1129
1130 static int erspan_validate(struct nlattr *tb[], struct nlattr *data[],
1131                            struct netlink_ext_ack *extack)
1132 {
1133         __be16 flags = 0;
1134         int ret;
1135
1136         if (!data)
1137                 return 0;
1138
1139         ret = ipgre_tap_validate(tb, data, extack);
1140         if (ret)
1141                 return ret;
1142
1143         /* ERSPAN should only have GRE sequence and key flag */
1144         if (data[IFLA_GRE_OFLAGS])
1145                 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1146         if (data[IFLA_GRE_IFLAGS])
1147                 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1148         if (!data[IFLA_GRE_COLLECT_METADATA] &&
1149             flags != (GRE_SEQ | GRE_KEY))
1150                 return -EINVAL;
1151
1152         /* ERSPAN Session ID only has 10-bit. Since we reuse
1153          * 32-bit key field as ID, check it's range.
1154          */
1155         if (data[IFLA_GRE_IKEY] &&
1156             (ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
1157                 return -EINVAL;
1158
1159         if (data[IFLA_GRE_OKEY] &&
1160             (ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))
1161                 return -EINVAL;
1162
1163         return 0;
1164 }
1165
1166 static int ipgre_netlink_parms(struct net_device *dev,
1167                                 struct nlattr *data[],
1168                                 struct nlattr *tb[],
1169                                 struct ip_tunnel_parm *parms,
1170                                 __u32 *fwmark)
1171 {
1172         struct ip_tunnel *t = netdev_priv(dev);
1173
1174         memset(parms, 0, sizeof(*parms));
1175
1176         parms->iph.protocol = IPPROTO_GRE;
1177
1178         if (!data)
1179                 return 0;
1180
1181         if (data[IFLA_GRE_LINK])
1182                 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1183
1184         if (data[IFLA_GRE_IFLAGS])
1185                 parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS]));
1186
1187         if (data[IFLA_GRE_OFLAGS])
1188                 parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS]));
1189
1190         if (data[IFLA_GRE_IKEY])
1191                 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1192
1193         if (data[IFLA_GRE_OKEY])
1194                 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1195
1196         if (data[IFLA_GRE_LOCAL])
1197                 parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]);
1198
1199         if (data[IFLA_GRE_REMOTE])
1200                 parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]);
1201
1202         if (data[IFLA_GRE_TTL])
1203                 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1204
1205         if (data[IFLA_GRE_TOS])
1206                 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1207
1208         if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) {
1209                 if (t->ignore_df)
1210                         return -EINVAL;
1211                 parms->iph.frag_off = htons(IP_DF);
1212         }
1213
1214         if (data[IFLA_GRE_COLLECT_METADATA]) {
1215                 t->collect_md = true;
1216                 if (dev->type == ARPHRD_IPGRE)
1217                         dev->type = ARPHRD_NONE;
1218         }
1219
1220         if (data[IFLA_GRE_IGNORE_DF]) {
1221                 if (nla_get_u8(data[IFLA_GRE_IGNORE_DF])
1222                   && (parms->iph.frag_off & htons(IP_DF)))
1223                         return -EINVAL;
1224                 t->ignore_df = !!nla_get_u8(data[IFLA_GRE_IGNORE_DF]);
1225         }
1226
1227         if (data[IFLA_GRE_FWMARK])
1228                 *fwmark = nla_get_u32(data[IFLA_GRE_FWMARK]);
1229
1230         if (data[IFLA_GRE_ERSPAN_VER]) {
1231                 t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);
1232
1233                 if (t->erspan_ver != 1 && t->erspan_ver != 2)
1234                         return -EINVAL;
1235         }
1236
1237         if (t->erspan_ver == 1) {
1238                 if (data[IFLA_GRE_ERSPAN_INDEX]) {
1239                         t->index = nla_get_u32(data[IFLA_GRE_ERSPAN_INDEX]);
1240                         if (t->index & ~INDEX_MASK)
1241                                 return -EINVAL;
1242                 }
1243         } else if (t->erspan_ver == 2) {
1244                 if (data[IFLA_GRE_ERSPAN_DIR]) {
1245                         t->dir = nla_get_u8(data[IFLA_GRE_ERSPAN_DIR]);
1246                         if (t->dir & ~(DIR_MASK >> DIR_OFFSET))
1247                                 return -EINVAL;
1248                 }
1249                 if (data[IFLA_GRE_ERSPAN_HWID]) {
1250                         t->hwid = nla_get_u16(data[IFLA_GRE_ERSPAN_HWID]);
1251                         if (t->hwid & ~(HWID_MASK >> HWID_OFFSET))
1252                                 return -EINVAL;
1253                 }
1254         }
1255
1256         return 0;
1257 }
1258
1259 /* This function returns true when ENCAP attributes are present in the nl msg */
1260 static bool ipgre_netlink_encap_parms(struct nlattr *data[],
1261                                       struct ip_tunnel_encap *ipencap)
1262 {
1263         bool ret = false;
1264
1265         memset(ipencap, 0, sizeof(*ipencap));
1266
1267         if (!data)
1268                 return ret;
1269
1270         if (data[IFLA_GRE_ENCAP_TYPE]) {
1271                 ret = true;
1272                 ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]);
1273         }
1274
1275         if (data[IFLA_GRE_ENCAP_FLAGS]) {
1276                 ret = true;
1277                 ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]);
1278         }
1279
1280         if (data[IFLA_GRE_ENCAP_SPORT]) {
1281                 ret = true;
1282                 ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]);
1283         }
1284
1285         if (data[IFLA_GRE_ENCAP_DPORT]) {
1286                 ret = true;
1287                 ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]);
1288         }
1289
1290         return ret;
1291 }
1292
1293 static int gre_tap_init(struct net_device *dev)
1294 {
1295         __gre_tunnel_init(dev);
1296         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1297         netif_keep_dst(dev);
1298
1299         return ip_tunnel_init(dev);
1300 }
1301
1302 static const struct net_device_ops gre_tap_netdev_ops = {
1303         .ndo_init               = gre_tap_init,
1304         .ndo_uninit             = ip_tunnel_uninit,
1305         .ndo_start_xmit         = gre_tap_xmit,
1306         .ndo_set_mac_address    = eth_mac_addr,
1307         .ndo_validate_addr      = eth_validate_addr,
1308         .ndo_change_mtu         = ip_tunnel_change_mtu,
1309         .ndo_get_stats64        = ip_tunnel_get_stats64,
1310         .ndo_get_iflink         = ip_tunnel_get_iflink,
1311         .ndo_fill_metadata_dst  = gre_fill_metadata_dst,
1312 };
1313
1314 static int erspan_tunnel_init(struct net_device *dev)
1315 {
1316         struct ip_tunnel *tunnel = netdev_priv(dev);
1317
1318         tunnel->tun_hlen = 8;
1319         tunnel->parms.iph.protocol = IPPROTO_GRE;
1320         tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
1321                        erspan_hdr_len(tunnel->erspan_ver);
1322
1323         dev->features           |= GRE_FEATURES;
1324         dev->hw_features        |= GRE_FEATURES;
1325         dev->priv_flags         |= IFF_LIVE_ADDR_CHANGE;
1326         netif_keep_dst(dev);
1327
1328         return ip_tunnel_init(dev);
1329 }
1330
1331 static const struct net_device_ops erspan_netdev_ops = {
1332         .ndo_init               = erspan_tunnel_init,
1333         .ndo_uninit             = ip_tunnel_uninit,
1334         .ndo_start_xmit         = erspan_xmit,
1335         .ndo_set_mac_address    = eth_mac_addr,
1336         .ndo_validate_addr      = eth_validate_addr,
1337         .ndo_change_mtu         = ip_tunnel_change_mtu,
1338         .ndo_get_stats64        = ip_tunnel_get_stats64,
1339         .ndo_get_iflink         = ip_tunnel_get_iflink,
1340         .ndo_fill_metadata_dst  = gre_fill_metadata_dst,
1341 };
1342
1343 static void ipgre_tap_setup(struct net_device *dev)
1344 {
1345         ether_setup(dev);
1346         dev->max_mtu = 0;
1347         dev->netdev_ops = &gre_tap_netdev_ops;
1348         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1349         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1350         ip_tunnel_setup(dev, gre_tap_net_id);
1351 }
1352
1353 static int ipgre_newlink(struct net *src_net, struct net_device *dev,
1354                          struct nlattr *tb[], struct nlattr *data[],
1355                          struct netlink_ext_ack *extack)
1356 {
1357         struct ip_tunnel_parm p;
1358         struct ip_tunnel_encap ipencap;
1359         __u32 fwmark = 0;
1360         int err;
1361
1362         if (ipgre_netlink_encap_parms(data, &ipencap)) {
1363                 struct ip_tunnel *t = netdev_priv(dev);
1364                 err = ip_tunnel_encap_setup(t, &ipencap);
1365
1366                 if (err < 0)
1367                         return err;
1368         }
1369
1370         err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1371         if (err < 0)
1372                 return err;
1373         return ip_tunnel_newlink(dev, tb, &p, fwmark);
1374 }
1375
1376 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1377                             struct nlattr *data[],
1378                             struct netlink_ext_ack *extack)
1379 {
1380         struct ip_tunnel *t = netdev_priv(dev);
1381         struct ip_tunnel_encap ipencap;
1382         __u32 fwmark = t->fwmark;
1383         struct ip_tunnel_parm p;
1384         int err;
1385
1386         if (ipgre_netlink_encap_parms(data, &ipencap)) {
1387                 err = ip_tunnel_encap_setup(t, &ipencap);
1388
1389                 if (err < 0)
1390                         return err;
1391         }
1392
1393         err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1394         if (err < 0)
1395                 return err;
1396
1397         err = ip_tunnel_changelink(dev, tb, &p, fwmark);
1398         if (err < 0)
1399                 return err;
1400
1401         t->parms.i_flags = p.i_flags;
1402         t->parms.o_flags = p.o_flags;
1403
1404         if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
1405                 ipgre_link_update(dev, !tb[IFLA_MTU]);
1406
1407         return 0;
1408 }
1409
1410 static size_t ipgre_get_size(const struct net_device *dev)
1411 {
1412         return
1413                 /* IFLA_GRE_LINK */
1414                 nla_total_size(4) +
1415                 /* IFLA_GRE_IFLAGS */
1416                 nla_total_size(2) +
1417                 /* IFLA_GRE_OFLAGS */
1418                 nla_total_size(2) +
1419                 /* IFLA_GRE_IKEY */
1420                 nla_total_size(4) +
1421                 /* IFLA_GRE_OKEY */
1422                 nla_total_size(4) +
1423                 /* IFLA_GRE_LOCAL */
1424                 nla_total_size(4) +
1425                 /* IFLA_GRE_REMOTE */
1426                 nla_total_size(4) +
1427                 /* IFLA_GRE_TTL */
1428                 nla_total_size(1) +
1429                 /* IFLA_GRE_TOS */
1430                 nla_total_size(1) +
1431                 /* IFLA_GRE_PMTUDISC */
1432                 nla_total_size(1) +
1433                 /* IFLA_GRE_ENCAP_TYPE */
1434                 nla_total_size(2) +
1435                 /* IFLA_GRE_ENCAP_FLAGS */
1436                 nla_total_size(2) +
1437                 /* IFLA_GRE_ENCAP_SPORT */
1438                 nla_total_size(2) +
1439                 /* IFLA_GRE_ENCAP_DPORT */
1440                 nla_total_size(2) +
1441                 /* IFLA_GRE_COLLECT_METADATA */
1442                 nla_total_size(0) +
1443                 /* IFLA_GRE_IGNORE_DF */
1444                 nla_total_size(1) +
1445                 /* IFLA_GRE_FWMARK */
1446                 nla_total_size(4) +
1447                 /* IFLA_GRE_ERSPAN_INDEX */
1448                 nla_total_size(4) +
1449                 /* IFLA_GRE_ERSPAN_VER */
1450                 nla_total_size(1) +
1451                 /* IFLA_GRE_ERSPAN_DIR */
1452                 nla_total_size(1) +
1453                 /* IFLA_GRE_ERSPAN_HWID */
1454                 nla_total_size(2) +
1455                 0;
1456 }
1457
1458 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1459 {
1460         struct ip_tunnel *t = netdev_priv(dev);
1461         struct ip_tunnel_parm *p = &t->parms;
1462
1463         if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1464             nla_put_be16(skb, IFLA_GRE_IFLAGS,
1465                          gre_tnl_flags_to_gre_flags(p->i_flags)) ||
1466             nla_put_be16(skb, IFLA_GRE_OFLAGS,
1467                          gre_tnl_flags_to_gre_flags(p->o_flags)) ||
1468             nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1469             nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1470             nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1471             nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1472             nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1473             nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1474             nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1475                        !!(p->iph.frag_off & htons(IP_DF))) ||
1476             nla_put_u32(skb, IFLA_GRE_FWMARK, t->fwmark))
1477                 goto nla_put_failure;
1478
1479         if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE,
1480                         t->encap.type) ||
1481             nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT,
1482                          t->encap.sport) ||
1483             nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT,
1484                          t->encap.dport) ||
1485             nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
1486                         t->encap.flags))
1487                 goto nla_put_failure;
1488
1489         if (nla_put_u8(skb, IFLA_GRE_IGNORE_DF, t->ignore_df))
1490                 goto nla_put_failure;
1491
1492         if (t->collect_md) {
1493                 if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA))
1494                         goto nla_put_failure;
1495         }
1496
1497         if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
1498                 goto nla_put_failure;
1499
1500         if (t->erspan_ver == 1) {
1501                 if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
1502                         goto nla_put_failure;
1503         } else if (t->erspan_ver == 2) {
1504                 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
1505                         goto nla_put_failure;
1506                 if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
1507                         goto nla_put_failure;
1508         }
1509
1510         return 0;
1511
1512 nla_put_failure:
1513         return -EMSGSIZE;
1514 }
1515
1516 static void erspan_setup(struct net_device *dev)
1517 {
1518         struct ip_tunnel *t = netdev_priv(dev);
1519
1520         ether_setup(dev);
1521         dev->netdev_ops = &erspan_netdev_ops;
1522         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1523         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1524         ip_tunnel_setup(dev, erspan_net_id);
1525         t->erspan_ver = 1;
1526 }
1527
1528 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1529         [IFLA_GRE_LINK]         = { .type = NLA_U32 },
1530         [IFLA_GRE_IFLAGS]       = { .type = NLA_U16 },
1531         [IFLA_GRE_OFLAGS]       = { .type = NLA_U16 },
1532         [IFLA_GRE_IKEY]         = { .type = NLA_U32 },
1533         [IFLA_GRE_OKEY]         = { .type = NLA_U32 },
1534         [IFLA_GRE_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1535         [IFLA_GRE_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1536         [IFLA_GRE_TTL]          = { .type = NLA_U8 },
1537         [IFLA_GRE_TOS]          = { .type = NLA_U8 },
1538         [IFLA_GRE_PMTUDISC]     = { .type = NLA_U8 },
1539         [IFLA_GRE_ENCAP_TYPE]   = { .type = NLA_U16 },
1540         [IFLA_GRE_ENCAP_FLAGS]  = { .type = NLA_U16 },
1541         [IFLA_GRE_ENCAP_SPORT]  = { .type = NLA_U16 },
1542         [IFLA_GRE_ENCAP_DPORT]  = { .type = NLA_U16 },
1543         [IFLA_GRE_COLLECT_METADATA]     = { .type = NLA_FLAG },
1544         [IFLA_GRE_IGNORE_DF]    = { .type = NLA_U8 },
1545         [IFLA_GRE_FWMARK]       = { .type = NLA_U32 },
1546         [IFLA_GRE_ERSPAN_INDEX] = { .type = NLA_U32 },
1547         [IFLA_GRE_ERSPAN_VER]   = { .type = NLA_U8 },
1548         [IFLA_GRE_ERSPAN_DIR]   = { .type = NLA_U8 },
1549         [IFLA_GRE_ERSPAN_HWID]  = { .type = NLA_U16 },
1550 };
1551
1552 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1553         .kind           = "gre",
1554         .maxtype        = IFLA_GRE_MAX,
1555         .policy         = ipgre_policy,
1556         .priv_size      = sizeof(struct ip_tunnel),
1557         .setup          = ipgre_tunnel_setup,
1558         .validate       = ipgre_tunnel_validate,
1559         .newlink        = ipgre_newlink,
1560         .changelink     = ipgre_changelink,
1561         .dellink        = ip_tunnel_dellink,
1562         .get_size       = ipgre_get_size,
1563         .fill_info      = ipgre_fill_info,
1564         .get_link_net   = ip_tunnel_get_link_net,
1565 };
1566
1567 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1568         .kind           = "gretap",
1569         .maxtype        = IFLA_GRE_MAX,
1570         .policy         = ipgre_policy,
1571         .priv_size      = sizeof(struct ip_tunnel),
1572         .setup          = ipgre_tap_setup,
1573         .validate       = ipgre_tap_validate,
1574         .newlink        = ipgre_newlink,
1575         .changelink     = ipgre_changelink,
1576         .dellink        = ip_tunnel_dellink,
1577         .get_size       = ipgre_get_size,
1578         .fill_info      = ipgre_fill_info,
1579         .get_link_net   = ip_tunnel_get_link_net,
1580 };
1581
1582 static struct rtnl_link_ops erspan_link_ops __read_mostly = {
1583         .kind           = "erspan",
1584         .maxtype        = IFLA_GRE_MAX,
1585         .policy         = ipgre_policy,
1586         .priv_size      = sizeof(struct ip_tunnel),
1587         .setup          = erspan_setup,
1588         .validate       = erspan_validate,
1589         .newlink        = ipgre_newlink,
1590         .changelink     = ipgre_changelink,
1591         .dellink        = ip_tunnel_dellink,
1592         .get_size       = ipgre_get_size,
1593         .fill_info      = ipgre_fill_info,
1594         .get_link_net   = ip_tunnel_get_link_net,
1595 };
1596
1597 struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
1598                                         u8 name_assign_type)
1599 {
1600         struct nlattr *tb[IFLA_MAX + 1];
1601         struct net_device *dev;
1602         LIST_HEAD(list_kill);
1603         struct ip_tunnel *t;
1604         int err;
1605
1606         memset(&tb, 0, sizeof(tb));
1607
1608         dev = rtnl_create_link(net, name, name_assign_type,
1609                                &ipgre_tap_ops, tb, NULL);
1610         if (IS_ERR(dev))
1611                 return dev;
1612
1613         /* Configure flow based GRE device. */
1614         t = netdev_priv(dev);
1615         t->collect_md = true;
1616
1617         err = ipgre_newlink(net, dev, tb, NULL, NULL);
1618         if (err < 0) {
1619                 free_netdev(dev);
1620                 return ERR_PTR(err);
1621         }
1622
1623         /* openvswitch users expect packet sizes to be unrestricted,
1624          * so set the largest MTU we can.
1625          */
1626         err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false);
1627         if (err)
1628                 goto out;
1629
1630         err = rtnl_configure_link(dev, NULL);
1631         if (err < 0)
1632                 goto out;
1633
1634         return dev;
1635 out:
1636         ip_tunnel_dellink(dev, &list_kill);
1637         unregister_netdevice_many(&list_kill);
1638         return ERR_PTR(err);
1639 }
1640 EXPORT_SYMBOL_GPL(gretap_fb_dev_create);
1641
1642 static int __net_init ipgre_tap_init_net(struct net *net)
1643 {
1644         return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
1645 }
1646
1647 static void __net_exit ipgre_tap_exit_batch_net(struct list_head *list_net)
1648 {
1649         ip_tunnel_delete_nets(list_net, gre_tap_net_id, &ipgre_tap_ops);
1650 }
1651
1652 static struct pernet_operations ipgre_tap_net_ops = {
1653         .init = ipgre_tap_init_net,
1654         .exit_batch = ipgre_tap_exit_batch_net,
1655         .id   = &gre_tap_net_id,
1656         .size = sizeof(struct ip_tunnel_net),
1657 };
1658
1659 static int __net_init erspan_init_net(struct net *net)
1660 {
1661         return ip_tunnel_init_net(net, erspan_net_id,
1662                                   &erspan_link_ops, "erspan0");
1663 }
1664
1665 static void __net_exit erspan_exit_batch_net(struct list_head *net_list)
1666 {
1667         ip_tunnel_delete_nets(net_list, erspan_net_id, &erspan_link_ops);
1668 }
1669
1670 static struct pernet_operations erspan_net_ops = {
1671         .init = erspan_init_net,
1672         .exit_batch = erspan_exit_batch_net,
1673         .id   = &erspan_net_id,
1674         .size = sizeof(struct ip_tunnel_net),
1675 };
1676
1677 static int __init ipgre_init(void)
1678 {
1679         int err;
1680
1681         pr_info("GRE over IPv4 tunneling driver\n");
1682
1683         err = register_pernet_device(&ipgre_net_ops);
1684         if (err < 0)
1685                 return err;
1686
1687         err = register_pernet_device(&ipgre_tap_net_ops);
1688         if (err < 0)
1689                 goto pnet_tap_failed;
1690
1691         err = register_pernet_device(&erspan_net_ops);
1692         if (err < 0)
1693                 goto pnet_erspan_failed;
1694
1695         err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1696         if (err < 0) {
1697                 pr_info("%s: can't add protocol\n", __func__);
1698                 goto add_proto_failed;
1699         }
1700
1701         err = rtnl_link_register(&ipgre_link_ops);
1702         if (err < 0)
1703                 goto rtnl_link_failed;
1704
1705         err = rtnl_link_register(&ipgre_tap_ops);
1706         if (err < 0)
1707                 goto tap_ops_failed;
1708
1709         err = rtnl_link_register(&erspan_link_ops);
1710         if (err < 0)
1711                 goto erspan_link_failed;
1712
1713         return 0;
1714
1715 erspan_link_failed:
1716         rtnl_link_unregister(&ipgre_tap_ops);
1717 tap_ops_failed:
1718         rtnl_link_unregister(&ipgre_link_ops);
1719 rtnl_link_failed:
1720         gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1721 add_proto_failed:
1722         unregister_pernet_device(&erspan_net_ops);
1723 pnet_erspan_failed:
1724         unregister_pernet_device(&ipgre_tap_net_ops);
1725 pnet_tap_failed:
1726         unregister_pernet_device(&ipgre_net_ops);
1727         return err;
1728 }
1729
1730 static void __exit ipgre_fini(void)
1731 {
1732         rtnl_link_unregister(&ipgre_tap_ops);
1733         rtnl_link_unregister(&ipgre_link_ops);
1734         rtnl_link_unregister(&erspan_link_ops);
1735         gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1736         unregister_pernet_device(&ipgre_tap_net_ops);
1737         unregister_pernet_device(&ipgre_net_ops);
1738         unregister_pernet_device(&erspan_net_ops);
1739 }
1740
1741 module_init(ipgre_init);
1742 module_exit(ipgre_fini);
1743 MODULE_LICENSE("GPL");
1744 MODULE_ALIAS_RTNL_LINK("gre");
1745 MODULE_ALIAS_RTNL_LINK("gretap");
1746 MODULE_ALIAS_RTNL_LINK("erspan");
1747 MODULE_ALIAS_NETDEV("gre0");
1748 MODULE_ALIAS_NETDEV("gretap0");
1749 MODULE_ALIAS_NETDEV("erspan0");