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