net/ipv4/ip_gre.c

   1 /*
   2  *      Linux NET3:     GRE over IP protocol decoder.
   3  *
   4  *      Authors: Alexey Kuznetsov ([email protected])
   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                 }
 785                 dev->features |= NETIF_F_LLTX;
 786         }
 787 }
 788
 789 static int ipgre_tunnel_ioctl(struct net_device *dev,
 790                               struct ifreq *ifr, int cmd)
 791 {
 792         struct ip_tunnel_parm p;
 793         int err;
 794
 795         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 796                 return -EFAULT;
 797
 798         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 799                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE ||
 800                     p.iph.ihl != 5 || (p.iph.frag_off & htons(~IP_DF)) ||
 801                     ((p.i_flags | p.o_flags) & (GRE_VERSION | GRE_ROUTING)))
 802                         return -EINVAL;
 803         }
 804
 805         p.i_flags = gre_flags_to_tnl_flags(p.i_flags);
 806         p.o_flags = gre_flags_to_tnl_flags(p.o_flags);
 807
 808         err = ip_tunnel_ioctl(dev, &p, cmd);
 809         if (err)
 810                 return err;
 811
 812         if (cmd == SIOCCHGTUNNEL) {
 813                 struct ip_tunnel *t = netdev_priv(dev);
 814
 815                 t->parms.i_flags = p.i_flags;
 816                 t->parms.o_flags = p.o_flags;
 817
 818                 if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
 819                         ipgre_link_update(dev, true);
 820         }
 821
 822         p.i_flags = gre_tnl_flags_to_gre_flags(p.i_flags);
 823         p.o_flags = gre_tnl_flags_to_gre_flags(p.o_flags);
 824
 825         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 826                 return -EFAULT;
 827
 828         return 0;
 829 }
 830
 831 /* Nice toy. Unfortunately, useless in real life :-)
 832    It allows to construct virtual multiprotocol broadcast "LAN"
 833    over the Internet, provided multicast routing is tuned.
 834
 835
 836    I have no idea was this bicycle invented before me,
 837    so that I had to set ARPHRD_IPGRE to a random value.
 838    I have an impression, that Cisco could make something similar,
 839    but this feature is apparently missing in IOS<=11.2(8).
 840
 841    I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks
 842    with broadcast 224.66.66.66. If you have access to mbone, play with me :-)
 843
 844    ping -t 255 224.66.66.66
 845
 846    If nobody answers, mbone does not work.
 847
 848    ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255
 849    ip addr add 10.66.66.<somewhat>/24 dev Universe
 850    ifconfig Universe up
 851    ifconfig Universe add fe80::<Your_real_addr>/10
 852    ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96
 853    ftp 10.66.66.66
 854    ...
 855    ftp fec0:6666:6666::193.233.7.65
 856    ...
 857  */
 858 static int ipgre_header(struct sk_buff *skb, struct net_device *dev,
 859                         unsigned short type,
 860                         const void *daddr, const void *saddr, unsigned int len)
 861 {
 862         struct ip_tunnel *t = netdev_priv(dev);
 863         struct iphdr *iph;
 864         struct gre_base_hdr *greh;
 865
 866         iph = skb_push(skb, t->hlen + sizeof(*iph));
 867         greh = (struct gre_base_hdr *)(iph+1);
 868         greh->flags = gre_tnl_flags_to_gre_flags(t->parms.o_flags);
 869         greh->protocol = htons(type);
 870
 871         memcpy(iph, &t->parms.iph, sizeof(struct iphdr));
 872
 873         /* Set the source hardware address. */
 874         if (saddr)
 875                 memcpy(&iph->saddr, saddr, 4);
 876         if (daddr)
 877                 memcpy(&iph->daddr, daddr, 4);
 878         if (iph->daddr)
 879                 return t->hlen + sizeof(*iph);
 880
 881         return -(t->hlen + sizeof(*iph));
 882 }
 883
 884 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr)
 885 {
 886         const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb);
 887         memcpy(haddr, &iph->saddr, 4);
 888         return 4;
 889 }
 890
 891 static const struct header_ops ipgre_header_ops = {
 892         .create = ipgre_header,
 893         .parse  = ipgre_header_parse,
 894 };
 895
 896 #ifdef CONFIG_NET_IPGRE_BROADCAST
 897 static int ipgre_open(struct net_device *dev)
 898 {
 899         struct ip_tunnel *t = netdev_priv(dev);
 900
 901         if (ipv4_is_multicast(t->parms.iph.daddr)) {
 902                 struct flowi4 fl4;
 903                 struct rtable *rt;
 904
 905                 rt = ip_route_output_gre(t->net, &fl4,
 906                                          t->parms.iph.daddr,
 907                                          t->parms.iph.saddr,
 908                                          t->parms.o_key,
 909                                          RT_TOS(t->parms.iph.tos),
 910                                          t->parms.link);
 911                 if (IS_ERR(rt))
 912                         return -EADDRNOTAVAIL;
 913                 dev = rt->dst.dev;
 914                 ip_rt_put(rt);
 915                 if (!__in_dev_get_rtnl(dev))
 916                         return -EADDRNOTAVAIL;
 917                 t->mlink = dev->ifindex;
 918                 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr);
 919         }
 920         return 0;
 921 }
 922
 923 static int ipgre_close(struct net_device *dev)
 924 {
 925         struct ip_tunnel *t = netdev_priv(dev);
 926
 927         if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) {
 928                 struct in_device *in_dev;
 929                 in_dev = inetdev_by_index(t->net, t->mlink);
 930                 if (in_dev)
 931                         ip_mc_dec_group(in_dev, t->parms.iph.daddr);
 932         }
 933         return 0;
 934 }
 935 #endif
 936
 937 static const struct net_device_ops ipgre_netdev_ops = {
 938         .ndo_init               = ipgre_tunnel_init,
 939         .ndo_uninit             = ip_tunnel_uninit,
 940 #ifdef CONFIG_NET_IPGRE_BROADCAST
 941         .ndo_open               = ipgre_open,
 942         .ndo_stop               = ipgre_close,
 943 #endif
 944         .ndo_start_xmit         = ipgre_xmit,
 945         .ndo_do_ioctl           = ipgre_tunnel_ioctl,
 946         .ndo_change_mtu         = ip_tunnel_change_mtu,
 947         .ndo_get_stats64        = ip_tunnel_get_stats64,
 948         .ndo_get_iflink         = ip_tunnel_get_iflink,
 949 };
 950
 951 #define GRE_FEATURES (NETIF_F_SG |              \
 952                       NETIF_F_FRAGLIST |        \
 953                       NETIF_F_HIGHDMA |         \
 954                       NETIF_F_HW_CSUM)
 955
 956 static void ipgre_tunnel_setup(struct net_device *dev)
 957 {
 958         dev->netdev_ops         = &ipgre_netdev_ops;
 959         dev->type               = ARPHRD_IPGRE;
 960         ip_tunnel_setup(dev, ipgre_net_id);
 961 }
 962
 963 static void __gre_tunnel_init(struct net_device *dev)
 964 {
 965         struct ip_tunnel *tunnel;
 966         int t_hlen;
 967
 968         tunnel = netdev_priv(dev);
 969         tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags);
 970         tunnel->parms.iph.protocol = IPPROTO_GRE;
 971
 972         tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen;
 973
 974         t_hlen = tunnel->hlen + sizeof(struct iphdr);
 975
 976         dev->features           |= GRE_FEATURES;
 977         dev->hw_features        |= GRE_FEATURES;
 978
 979         if (!(tunnel->parms.o_flags & TUNNEL_SEQ)) {
 980                 /* TCP offload with GRE SEQ is not supported, nor
 981                  * can we support 2 levels of outer headers requiring
 982                  * an update.
 983                  */
 984                 if (!(tunnel->parms.o_flags & TUNNEL_CSUM) ||
 985                     (tunnel->encap.type == TUNNEL_ENCAP_NONE)) {
 986                         dev->features    |= NETIF_F_GSO_SOFTWARE;
 987                         dev->hw_features |= NETIF_F_GSO_SOFTWARE;
 988                 }
 989
 990                 /* Can use a lockless transmit, unless we generate
 991                  * output sequences
 992                  */
 993                 dev->features |= NETIF_F_LLTX;
 994         }
 995 }
 996
 997 static int ipgre_tunnel_init(struct net_device *dev)
 998 {
 999         struct ip_tunnel *tunnel = netdev_priv(dev);
1000         struct iphdr *iph = &tunnel->parms.iph;
1001
1002         __gre_tunnel_init(dev);
1003
1004         memcpy(dev->dev_addr, &iph->saddr, 4);
1005         memcpy(dev->broadcast, &iph->daddr, 4);
1006
1007         dev->flags              = IFF_NOARP;
1008         netif_keep_dst(dev);
1009         dev->addr_len           = 4;
1010
1011         if (iph->daddr && !tunnel->collect_md) {
1012 #ifdef CONFIG_NET_IPGRE_BROADCAST
1013                 if (ipv4_is_multicast(iph->daddr)) {
1014                         if (!iph->saddr)
1015                                 return -EINVAL;
1016                         dev->flags = IFF_BROADCAST;
1017                         dev->header_ops = &ipgre_header_ops;
1018                 }
1019 #endif
1020         } else if (!tunnel->collect_md) {
1021                 dev->header_ops = &ipgre_header_ops;
1022         }
1023
1024         return ip_tunnel_init(dev);
1025 }
1026
1027 static const struct gre_protocol ipgre_protocol = {
1028         .handler     = gre_rcv,
1029         .err_handler = gre_err,
1030 };
1031
1032 static int __net_init ipgre_init_net(struct net *net)
1033 {
1034         return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL);
1035 }
1036
1037 static void __net_exit ipgre_exit_batch_net(struct list_head *list_net)
1038 {
1039         ip_tunnel_delete_nets(list_net, ipgre_net_id, &ipgre_link_ops);
1040 }
1041
1042 static struct pernet_operations ipgre_net_ops = {
1043         .init = ipgre_init_net,
1044         .exit_batch = ipgre_exit_batch_net,
1045         .id   = &ipgre_net_id,
1046         .size = sizeof(struct ip_tunnel_net),
1047 };
1048
1049 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[],
1050                                  struct netlink_ext_ack *extack)
1051 {
1052         __be16 flags;
1053
1054         if (!data)
1055                 return 0;
1056
1057         flags = 0;
1058         if (data[IFLA_GRE_IFLAGS])
1059                 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1060         if (data[IFLA_GRE_OFLAGS])
1061                 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1062         if (flags & (GRE_VERSION|GRE_ROUTING))
1063                 return -EINVAL;
1064
1065         if (data[IFLA_GRE_COLLECT_METADATA] &&
1066             data[IFLA_GRE_ENCAP_TYPE] &&
1067             nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE)
1068                 return -EINVAL;
1069
1070         return 0;
1071 }
1072
1073 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[],
1074                               struct netlink_ext_ack *extack)
1075 {
1076         __be32 daddr;
1077
1078         if (tb[IFLA_ADDRESS]) {
1079                 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
1080                         return -EINVAL;
1081                 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
1082                         return -EADDRNOTAVAIL;
1083         }
1084
1085         if (!data)
1086                 goto out;
1087
1088         if (data[IFLA_GRE_REMOTE]) {
1089                 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4);
1090                 if (!daddr)
1091                         return -EINVAL;
1092         }
1093
1094 out:
1095         return ipgre_tunnel_validate(tb, data, extack);
1096 }
1097
1098 static int erspan_validate(struct nlattr *tb[], struct nlattr *data[],
1099                            struct netlink_ext_ack *extack)
1100 {
1101         __be16 flags = 0;
1102         int ret;
1103
1104         if (!data)
1105                 return 0;
1106
1107         ret = ipgre_tap_validate(tb, data, extack);
1108         if (ret)
1109                 return ret;
1110
1111         /* ERSPAN should only have GRE sequence and key flag */
1112         if (data[IFLA_GRE_OFLAGS])
1113                 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]);
1114         if (data[IFLA_GRE_IFLAGS])
1115                 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]);
1116         if (!data[IFLA_GRE_COLLECT_METADATA] &&
1117             flags != (GRE_SEQ | GRE_KEY))
1118                 return -EINVAL;
1119
1120         /* ERSPAN Session ID only has 10-bit. Since we reuse
1121          * 32-bit key field as ID, check it's range.
1122          */
1123         if (data[IFLA_GRE_IKEY] &&
1124             (ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK))
1125                 return -EINVAL;
1126
1127         if (data[IFLA_GRE_OKEY] &&
1128             (ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK))
1129                 return -EINVAL;
1130
1131         return 0;
1132 }
1133
1134 static int ipgre_netlink_parms(struct net_device *dev,
1135                                 struct nlattr *data[],
1136                                 struct nlattr *tb[],
1137                                 struct ip_tunnel_parm *parms,
1138                                 __u32 *fwmark)
1139 {
1140         struct ip_tunnel *t = netdev_priv(dev);
1141
1142         memset(parms, 0, sizeof(*parms));
1143
1144         parms->iph.protocol = IPPROTO_GRE;
1145
1146         if (!data)
1147                 return 0;
1148
1149         if (data[IFLA_GRE_LINK])
1150                 parms->link = nla_get_u32(data[IFLA_GRE_LINK]);
1151
1152         if (data[IFLA_GRE_IFLAGS])
1153                 parms->i_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_IFLAGS]));
1154
1155         if (data[IFLA_GRE_OFLAGS])
1156                 parms->o_flags = gre_flags_to_tnl_flags(nla_get_be16(data[IFLA_GRE_OFLAGS]));
1157
1158         if (data[IFLA_GRE_IKEY])
1159                 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]);
1160
1161         if (data[IFLA_GRE_OKEY])
1162                 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]);
1163
1164         if (data[IFLA_GRE_LOCAL])
1165                 parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]);
1166
1167         if (data[IFLA_GRE_REMOTE])
1168                 parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]);
1169
1170         if (data[IFLA_GRE_TTL])
1171                 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]);
1172
1173         if (data[IFLA_GRE_TOS])
1174                 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]);
1175
1176         if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) {
1177                 if (t->ignore_df)
1178                         return -EINVAL;
1179                 parms->iph.frag_off = htons(IP_DF);
1180         }
1181
1182         if (data[IFLA_GRE_COLLECT_METADATA]) {
1183                 t->collect_md = true;
1184                 if (dev->type == ARPHRD_IPGRE)
1185                         dev->type = ARPHRD_NONE;
1186         }
1187
1188         if (data[IFLA_GRE_IGNORE_DF]) {
1189                 if (nla_get_u8(data[IFLA_GRE_IGNORE_DF])
1190                   && (parms->iph.frag_off & htons(IP_DF)))
1191                         return -EINVAL;
1192                 t->ignore_df = !!nla_get_u8(data[IFLA_GRE_IGNORE_DF]);
1193         }
1194
1195         if (data[IFLA_GRE_FWMARK])
1196                 *fwmark = nla_get_u32(data[IFLA_GRE_FWMARK]);
1197
1198         if (data[IFLA_GRE_ERSPAN_VER]) {
1199                 t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]);
1200
1201                 if (t->erspan_ver != 1 && t->erspan_ver != 2)
1202                         return -EINVAL;
1203         }
1204
1205         if (t->erspan_ver == 1) {
1206                 if (data[IFLA_GRE_ERSPAN_INDEX]) {
1207                         t->index = nla_get_u32(data[IFLA_GRE_ERSPAN_INDEX]);
1208                         if (t->index & ~INDEX_MASK)
1209                                 return -EINVAL;
1210                 }
1211         } else if (t->erspan_ver == 2) {
1212                 if (data[IFLA_GRE_ERSPAN_DIR]) {
1213                         t->dir = nla_get_u8(data[IFLA_GRE_ERSPAN_DIR]);
1214                         if (t->dir & ~(DIR_MASK >> DIR_OFFSET))
1215                                 return -EINVAL;
1216                 }
1217                 if (data[IFLA_GRE_ERSPAN_HWID]) {
1218                         t->hwid = nla_get_u16(data[IFLA_GRE_ERSPAN_HWID]);
1219                         if (t->hwid & ~(HWID_MASK >> HWID_OFFSET))
1220                                 return -EINVAL;
1221                 }
1222         }
1223
1224         return 0;
1225 }
1226
1227 /* This function returns true when ENCAP attributes are present in the nl msg */
1228 static bool ipgre_netlink_encap_parms(struct nlattr *data[],
1229                                       struct ip_tunnel_encap *ipencap)
1230 {
1231         bool ret = false;
1232
1233         memset(ipencap, 0, sizeof(*ipencap));
1234
1235         if (!data)
1236                 return ret;
1237
1238         if (data[IFLA_GRE_ENCAP_TYPE]) {
1239                 ret = true;
1240                 ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]);
1241         }
1242
1243         if (data[IFLA_GRE_ENCAP_FLAGS]) {
1244                 ret = true;
1245                 ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]);
1246         }
1247
1248         if (data[IFLA_GRE_ENCAP_SPORT]) {
1249                 ret = true;
1250                 ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]);
1251         }
1252
1253         if (data[IFLA_GRE_ENCAP_DPORT]) {
1254                 ret = true;
1255                 ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]);
1256         }
1257
1258         return ret;
1259 }
1260
1261 static int gre_tap_init(struct net_device *dev)
1262 {
1263         __gre_tunnel_init(dev);
1264         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1265         netif_keep_dst(dev);
1266
1267         return ip_tunnel_init(dev);
1268 }
1269
1270 static const struct net_device_ops gre_tap_netdev_ops = {
1271         .ndo_init               = gre_tap_init,
1272         .ndo_uninit             = ip_tunnel_uninit,
1273         .ndo_start_xmit         = gre_tap_xmit,
1274         .ndo_set_mac_address    = eth_mac_addr,
1275         .ndo_validate_addr      = eth_validate_addr,
1276         .ndo_change_mtu         = ip_tunnel_change_mtu,
1277         .ndo_get_stats64        = ip_tunnel_get_stats64,
1278         .ndo_get_iflink         = ip_tunnel_get_iflink,
1279         .ndo_fill_metadata_dst  = gre_fill_metadata_dst,
1280 };
1281
1282 static int erspan_tunnel_init(struct net_device *dev)
1283 {
1284         struct ip_tunnel *tunnel = netdev_priv(dev);
1285         int t_hlen;
1286
1287         tunnel->tun_hlen = 8;
1288         tunnel->parms.iph.protocol = IPPROTO_GRE;
1289         tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen +
1290                        erspan_hdr_len(tunnel->erspan_ver);
1291         t_hlen = tunnel->hlen + sizeof(struct iphdr);
1292
1293         dev->features           |= GRE_FEATURES;
1294         dev->hw_features        |= GRE_FEATURES;
1295         dev->priv_flags         |= IFF_LIVE_ADDR_CHANGE;
1296         netif_keep_dst(dev);
1297
1298         return ip_tunnel_init(dev);
1299 }
1300
1301 static const struct net_device_ops erspan_netdev_ops = {
1302         .ndo_init               = erspan_tunnel_init,
1303         .ndo_uninit             = ip_tunnel_uninit,
1304         .ndo_start_xmit         = erspan_xmit,
1305         .ndo_set_mac_address    = eth_mac_addr,
1306         .ndo_validate_addr      = eth_validate_addr,
1307         .ndo_change_mtu         = ip_tunnel_change_mtu,
1308         .ndo_get_stats64        = ip_tunnel_get_stats64,
1309         .ndo_get_iflink         = ip_tunnel_get_iflink,
1310         .ndo_fill_metadata_dst  = gre_fill_metadata_dst,
1311 };
1312
1313 static void ipgre_tap_setup(struct net_device *dev)
1314 {
1315         ether_setup(dev);
1316         dev->max_mtu = 0;
1317         dev->netdev_ops = &gre_tap_netdev_ops;
1318         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1319         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1320         ip_tunnel_setup(dev, gre_tap_net_id);
1321 }
1322
1323 bool is_gretap_dev(const struct net_device *dev)
1324 {
1325         return dev->netdev_ops == &gre_tap_netdev_ops;
1326 }
1327 EXPORT_SYMBOL_GPL(is_gretap_dev);
1328
1329 static int ipgre_newlink(struct net *src_net, struct net_device *dev,
1330                          struct nlattr *tb[], struct nlattr *data[],
1331                          struct netlink_ext_ack *extack)
1332 {
1333         struct ip_tunnel_parm p;
1334         struct ip_tunnel_encap ipencap;
1335         __u32 fwmark = 0;
1336         int err;
1337
1338         if (ipgre_netlink_encap_parms(data, &ipencap)) {
1339                 struct ip_tunnel *t = netdev_priv(dev);
1340                 err = ip_tunnel_encap_setup(t, &ipencap);
1341
1342                 if (err < 0)
1343                         return err;
1344         }
1345
1346         err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1347         if (err < 0)
1348                 return err;
1349         return ip_tunnel_newlink(dev, tb, &p, fwmark);
1350 }
1351
1352 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[],
1353                             struct nlattr *data[],
1354                             struct netlink_ext_ack *extack)
1355 {
1356         struct ip_tunnel *t = netdev_priv(dev);
1357         struct ip_tunnel_encap ipencap;
1358         __u32 fwmark = t->fwmark;
1359         struct ip_tunnel_parm p;
1360         int err;
1361
1362         if (ipgre_netlink_encap_parms(data, &ipencap)) {
1363                 err = ip_tunnel_encap_setup(t, &ipencap);
1364
1365                 if (err < 0)
1366                         return err;
1367         }
1368
1369         err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark);
1370         if (err < 0)
1371                 return err;
1372
1373         err = ip_tunnel_changelink(dev, tb, &p, fwmark);
1374         if (err < 0)
1375                 return err;
1376
1377         t->parms.i_flags = p.i_flags;
1378         t->parms.o_flags = p.o_flags;
1379
1380         if (strcmp(dev->rtnl_link_ops->kind, "erspan"))
1381                 ipgre_link_update(dev, !tb[IFLA_MTU]);
1382
1383         return 0;
1384 }
1385
1386 static size_t ipgre_get_size(const struct net_device *dev)
1387 {
1388         return
1389                 /* IFLA_GRE_LINK */
1390                 nla_total_size(4) +
1391                 /* IFLA_GRE_IFLAGS */
1392                 nla_total_size(2) +
1393                 /* IFLA_GRE_OFLAGS */
1394                 nla_total_size(2) +
1395                 /* IFLA_GRE_IKEY */
1396                 nla_total_size(4) +
1397                 /* IFLA_GRE_OKEY */
1398                 nla_total_size(4) +
1399                 /* IFLA_GRE_LOCAL */
1400                 nla_total_size(4) +
1401                 /* IFLA_GRE_REMOTE */
1402                 nla_total_size(4) +
1403                 /* IFLA_GRE_TTL */
1404                 nla_total_size(1) +
1405                 /* IFLA_GRE_TOS */
1406                 nla_total_size(1) +
1407                 /* IFLA_GRE_PMTUDISC */
1408                 nla_total_size(1) +
1409                 /* IFLA_GRE_ENCAP_TYPE */
1410                 nla_total_size(2) +
1411                 /* IFLA_GRE_ENCAP_FLAGS */
1412                 nla_total_size(2) +
1413                 /* IFLA_GRE_ENCAP_SPORT */
1414                 nla_total_size(2) +
1415                 /* IFLA_GRE_ENCAP_DPORT */
1416                 nla_total_size(2) +
1417                 /* IFLA_GRE_COLLECT_METADATA */
1418                 nla_total_size(0) +
1419                 /* IFLA_GRE_IGNORE_DF */
1420                 nla_total_size(1) +
1421                 /* IFLA_GRE_FWMARK */
1422                 nla_total_size(4) +
1423                 /* IFLA_GRE_ERSPAN_INDEX */
1424                 nla_total_size(4) +
1425                 /* IFLA_GRE_ERSPAN_VER */
1426                 nla_total_size(1) +
1427                 /* IFLA_GRE_ERSPAN_DIR */
1428                 nla_total_size(1) +
1429                 /* IFLA_GRE_ERSPAN_HWID */
1430                 nla_total_size(2) +
1431                 0;
1432 }
1433
1434 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev)
1435 {
1436         struct ip_tunnel *t = netdev_priv(dev);
1437         struct ip_tunnel_parm *p = &t->parms;
1438
1439         if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) ||
1440             nla_put_be16(skb, IFLA_GRE_IFLAGS,
1441                          gre_tnl_flags_to_gre_flags(p->i_flags)) ||
1442             nla_put_be16(skb, IFLA_GRE_OFLAGS,
1443                          gre_tnl_flags_to_gre_flags(p->o_flags)) ||
1444             nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) ||
1445             nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) ||
1446             nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) ||
1447             nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) ||
1448             nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) ||
1449             nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) ||
1450             nla_put_u8(skb, IFLA_GRE_PMTUDISC,
1451                        !!(p->iph.frag_off & htons(IP_DF))) ||
1452             nla_put_u32(skb, IFLA_GRE_FWMARK, t->fwmark))
1453                 goto nla_put_failure;
1454
1455         if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE,
1456                         t->encap.type) ||
1457             nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT,
1458                          t->encap.sport) ||
1459             nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT,
1460                          t->encap.dport) ||
1461             nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS,
1462                         t->encap.flags))
1463                 goto nla_put_failure;
1464
1465         if (nla_put_u8(skb, IFLA_GRE_IGNORE_DF, t->ignore_df))
1466                 goto nla_put_failure;
1467
1468         if (t->collect_md) {
1469                 if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA))
1470                         goto nla_put_failure;
1471         }
1472
1473         if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver))
1474                 goto nla_put_failure;
1475
1476         if (t->erspan_ver == 1) {
1477                 if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index))
1478                         goto nla_put_failure;
1479         } else if (t->erspan_ver == 2) {
1480                 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir))
1481                         goto nla_put_failure;
1482                 if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid))
1483                         goto nla_put_failure;
1484         }
1485
1486         return 0;
1487
1488 nla_put_failure:
1489         return -EMSGSIZE;
1490 }
1491
1492 static void erspan_setup(struct net_device *dev)
1493 {
1494         ether_setup(dev);
1495         dev->netdev_ops = &erspan_netdev_ops;
1496         dev->priv_flags &= ~IFF_TX_SKB_SHARING;
1497         dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;
1498         ip_tunnel_setup(dev, erspan_net_id);
1499 }
1500
1501 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = {
1502         [IFLA_GRE_LINK]         = { .type = NLA_U32 },
1503         [IFLA_GRE_IFLAGS]       = { .type = NLA_U16 },
1504         [IFLA_GRE_OFLAGS]       = { .type = NLA_U16 },
1505         [IFLA_GRE_IKEY]         = { .type = NLA_U32 },
1506         [IFLA_GRE_OKEY]         = { .type = NLA_U32 },
1507         [IFLA_GRE_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
1508         [IFLA_GRE_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
1509         [IFLA_GRE_TTL]          = { .type = NLA_U8 },
1510         [IFLA_GRE_TOS]          = { .type = NLA_U8 },
1511         [IFLA_GRE_PMTUDISC]     = { .type = NLA_U8 },
1512         [IFLA_GRE_ENCAP_TYPE]   = { .type = NLA_U16 },
1513         [IFLA_GRE_ENCAP_FLAGS]  = { .type = NLA_U16 },
1514         [IFLA_GRE_ENCAP_SPORT]  = { .type = NLA_U16 },
1515         [IFLA_GRE_ENCAP_DPORT]  = { .type = NLA_U16 },
1516         [IFLA_GRE_COLLECT_METADATA]     = { .type = NLA_FLAG },
1517         [IFLA_GRE_IGNORE_DF]    = { .type = NLA_U8 },
1518         [IFLA_GRE_FWMARK]       = { .type = NLA_U32 },
1519         [IFLA_GRE_ERSPAN_INDEX] = { .type = NLA_U32 },
1520         [IFLA_GRE_ERSPAN_VER]   = { .type = NLA_U8 },
1521         [IFLA_GRE_ERSPAN_DIR]   = { .type = NLA_U8 },
1522         [IFLA_GRE_ERSPAN_HWID]  = { .type = NLA_U16 },
1523 };
1524
1525 static struct rtnl_link_ops ipgre_link_ops __read_mostly = {
1526         .kind           = "gre",
1527         .maxtype        = IFLA_GRE_MAX,
1528         .policy         = ipgre_policy,
1529         .priv_size      = sizeof(struct ip_tunnel),
1530         .setup          = ipgre_tunnel_setup,
1531         .validate       = ipgre_tunnel_validate,
1532         .newlink        = ipgre_newlink,
1533         .changelink     = ipgre_changelink,
1534         .dellink        = ip_tunnel_dellink,
1535         .get_size       = ipgre_get_size,
1536         .fill_info      = ipgre_fill_info,
1537         .get_link_net   = ip_tunnel_get_link_net,
1538 };
1539
1540 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = {
1541         .kind           = "gretap",
1542         .maxtype        = IFLA_GRE_MAX,
1543         .policy         = ipgre_policy,
1544         .priv_size      = sizeof(struct ip_tunnel),
1545         .setup          = ipgre_tap_setup,
1546         .validate       = ipgre_tap_validate,
1547         .newlink        = ipgre_newlink,
1548         .changelink     = ipgre_changelink,
1549         .dellink        = ip_tunnel_dellink,
1550         .get_size       = ipgre_get_size,
1551         .fill_info      = ipgre_fill_info,
1552         .get_link_net   = ip_tunnel_get_link_net,
1553 };
1554
1555 static struct rtnl_link_ops erspan_link_ops __read_mostly = {
1556         .kind           = "erspan",
1557         .maxtype        = IFLA_GRE_MAX,
1558         .policy         = ipgre_policy,
1559         .priv_size      = sizeof(struct ip_tunnel),
1560         .setup          = erspan_setup,
1561         .validate       = erspan_validate,
1562         .newlink        = ipgre_newlink,
1563         .changelink     = ipgre_changelink,
1564         .dellink        = ip_tunnel_dellink,
1565         .get_size       = ipgre_get_size,
1566         .fill_info      = ipgre_fill_info,
1567         .get_link_net   = ip_tunnel_get_link_net,
1568 };
1569
1570 struct net_device *gretap_fb_dev_create(struct net *net, const char *name,
1571                                         u8 name_assign_type)
1572 {
1573         struct nlattr *tb[IFLA_MAX + 1];
1574         struct net_device *dev;
1575         LIST_HEAD(list_kill);
1576         struct ip_tunnel *t;
1577         int err;
1578
1579         memset(&tb, 0, sizeof(tb));
1580
1581         dev = rtnl_create_link(net, name, name_assign_type,
1582                                &ipgre_tap_ops, tb);
1583         if (IS_ERR(dev))
1584                 return dev;
1585
1586         /* Configure flow based GRE device. */
1587         t = netdev_priv(dev);
1588         t->collect_md = true;
1589
1590         err = ipgre_newlink(net, dev, tb, NULL, NULL);
1591         if (err < 0) {
1592                 free_netdev(dev);
1593                 return ERR_PTR(err);
1594         }
1595
1596         /* openvswitch users expect packet sizes to be unrestricted,
1597          * so set the largest MTU we can.
1598          */
1599         err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false);
1600         if (err)
1601                 goto out;
1602
1603         err = rtnl_configure_link(dev, NULL);
1604         if (err < 0)
1605                 goto out;
1606
1607         return dev;
1608 out:
1609         ip_tunnel_dellink(dev, &list_kill);
1610         unregister_netdevice_many(&list_kill);
1611         return ERR_PTR(err);
1612 }
1613 EXPORT_SYMBOL_GPL(gretap_fb_dev_create);
1614
1615 static int __net_init ipgre_tap_init_net(struct net *net)
1616 {
1617         return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0");
1618 }
1619
1620 static void __net_exit ipgre_tap_exit_batch_net(struct list_head *list_net)
1621 {
1622         ip_tunnel_delete_nets(list_net, gre_tap_net_id, &ipgre_tap_ops);
1623 }
1624
1625 static struct pernet_operations ipgre_tap_net_ops = {
1626         .init = ipgre_tap_init_net,
1627         .exit_batch = ipgre_tap_exit_batch_net,
1628         .id   = &gre_tap_net_id,
1629         .size = sizeof(struct ip_tunnel_net),
1630 };
1631
1632 static int __net_init erspan_init_net(struct net *net)
1633 {
1634         return ip_tunnel_init_net(net, erspan_net_id,
1635                                   &erspan_link_ops, "erspan0");
1636 }
1637
1638 static void __net_exit erspan_exit_batch_net(struct list_head *net_list)
1639 {
1640         ip_tunnel_delete_nets(net_list, erspan_net_id, &erspan_link_ops);
1641 }
1642
1643 static struct pernet_operations erspan_net_ops = {
1644         .init = erspan_init_net,
1645         .exit_batch = erspan_exit_batch_net,
1646         .id   = &erspan_net_id,
1647         .size = sizeof(struct ip_tunnel_net),
1648 };
1649
1650 static int __init ipgre_init(void)
1651 {
1652         int err;
1653
1654         pr_info("GRE over IPv4 tunneling driver\n");
1655
1656         err = register_pernet_device(&ipgre_net_ops);
1657         if (err < 0)
1658                 return err;
1659
1660         err = register_pernet_device(&ipgre_tap_net_ops);
1661         if (err < 0)
1662                 goto pnet_tap_failed;
1663
1664         err = register_pernet_device(&erspan_net_ops);
1665         if (err < 0)
1666                 goto pnet_erspan_failed;
1667
1668         err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
1669         if (err < 0) {
1670                 pr_info("%s: can't add protocol\n", __func__);
1671                 goto add_proto_failed;
1672         }
1673
1674         err = rtnl_link_register(&ipgre_link_ops);
1675         if (err < 0)
1676                 goto rtnl_link_failed;
1677
1678         err = rtnl_link_register(&ipgre_tap_ops);
1679         if (err < 0)
1680                 goto tap_ops_failed;
1681
1682         err = rtnl_link_register(&erspan_link_ops);
1683         if (err < 0)
1684                 goto erspan_link_failed;
1685
1686         return 0;
1687
1688 erspan_link_failed:
1689         rtnl_link_unregister(&ipgre_tap_ops);
1690 tap_ops_failed:
1691         rtnl_link_unregister(&ipgre_link_ops);
1692 rtnl_link_failed:
1693         gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1694 add_proto_failed:
1695         unregister_pernet_device(&erspan_net_ops);
1696 pnet_erspan_failed:
1697         unregister_pernet_device(&ipgre_tap_net_ops);
1698 pnet_tap_failed:
1699         unregister_pernet_device(&ipgre_net_ops);
1700         return err;
1701 }
1702
1703 static void __exit ipgre_fini(void)
1704 {
1705         rtnl_link_unregister(&ipgre_tap_ops);
1706         rtnl_link_unregister(&ipgre_link_ops);
1707         rtnl_link_unregister(&erspan_link_ops);
1708         gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
1709         unregister_pernet_device(&ipgre_tap_net_ops);
1710         unregister_pernet_device(&ipgre_net_ops);
1711         unregister_pernet_device(&erspan_net_ops);
1712 }
1713
1714 module_init(ipgre_init);
1715 module_exit(ipgre_fini);
1716 MODULE_LICENSE("GPL");
1717 MODULE_ALIAS_RTNL_LINK("gre");
1718 MODULE_ALIAS_RTNL_LINK("gretap");
1719 MODULE_ALIAS_RTNL_LINK("erspan");
1720 MODULE_ALIAS_NETDEV("gre0");
1721 MODULE_ALIAS_NETDEV("gretap0");
1722 MODULE_ALIAS_NETDEV("erspan0");