net/ipv4/ip_tunnel.c

   1 /*
   2  * Copyright (c) 2013 Nicira, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of version 2 of the GNU General Public
   6  * License as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program; if not, write to the Free Software
  15  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  16  * 02110-1301, USA
  17  */
  18
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/capability.h>
  22 #include <linux/module.h>
  23 #include <linux/types.h>
  24 #include <linux/kernel.h>
  25 #include <linux/slab.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/skbuff.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/in.h>
  30 #include <linux/tcp.h>
  31 #include <linux/udp.h>
  32 #include <linux/if_arp.h>
  33 #include <linux/mroute.h>
  34 #include <linux/init.h>
  35 #include <linux/in6.h>
  36 #include <linux/inetdevice.h>
  37 #include <linux/igmp.h>
  38 #include <linux/netfilter_ipv4.h>
  39 #include <linux/etherdevice.h>
  40 #include <linux/if_ether.h>
  41 #include <linux/if_vlan.h>
  42 #include <linux/rculist.h>
  43 #include <linux/err.h>
  44
  45 #include <net/sock.h>
  46 #include <net/ip.h>
  47 #include <net/icmp.h>
  48 #include <net/protocol.h>
  49 #include <net/ip_tunnels.h>
  50 #include <net/arp.h>
  51 #include <net/checksum.h>
  52 #include <net/dsfield.h>
  53 #include <net/inet_ecn.h>
  54 #include <net/xfrm.h>
  55 #include <net/net_namespace.h>
  56 #include <net/netns/generic.h>
  57 #include <net/rtnetlink.h>
  58 #include <net/udp.h>
  59
  60 #if IS_ENABLED(CONFIG_IPV6)
  61 #include <net/ipv6.h>
  62 #include <net/ip6_fib.h>
  63 #include <net/ip6_route.h>
  64 #endif
  65
  66 static unsigned int ip_tunnel_hash(__be32 key, __be32 remote)
  67 {
  68         return hash_32((__force u32)key ^ (__force u32)remote,
  69                          IP_TNL_HASH_BITS);
  70 }
  71
  72 static void __tunnel_dst_set(struct ip_tunnel_dst *idst,
  73                              struct dst_entry *dst, __be32 saddr)
  74 {
  75         struct dst_entry *old_dst;
  76
  77         dst_clone(dst);
  78         old_dst = xchg((__force struct dst_entry **)&idst->dst, dst);
  79         dst_release(old_dst);
  80         idst->saddr = saddr;
  81 }
  82
  83 static noinline void tunnel_dst_set(struct ip_tunnel *t,
  84                            struct dst_entry *dst, __be32 saddr)
  85 {
  86         __tunnel_dst_set(raw_cpu_ptr(t->dst_cache), dst, saddr);
  87 }
  88
  89 static void tunnel_dst_reset(struct ip_tunnel *t)
  90 {
  91         tunnel_dst_set(t, NULL, 0);
  92 }
  93
  94 void ip_tunnel_dst_reset_all(struct ip_tunnel *t)
  95 {
  96         int i;
  97
  98         for_each_possible_cpu(i)
  99                 __tunnel_dst_set(per_cpu_ptr(t->dst_cache, i), NULL, 0);
 100 }
 101 EXPORT_SYMBOL(ip_tunnel_dst_reset_all);
 102
 103 static struct rtable *tunnel_rtable_get(struct ip_tunnel *t,
 104                                         u32 cookie, __be32 *saddr)
 105 {
 106         struct ip_tunnel_dst *idst;
 107         struct dst_entry *dst;
 108
 109         rcu_read_lock();
 110         idst = raw_cpu_ptr(t->dst_cache);
 111         dst = rcu_dereference(idst->dst);
 112         if (dst && !atomic_inc_not_zero(&dst->__refcnt))
 113                 dst = NULL;
 114         if (dst) {
 115                 if (!dst->obsolete || dst->ops->check(dst, cookie)) {
 116                         *saddr = idst->saddr;
 117                 } else {
 118                         tunnel_dst_reset(t);
 119                         dst_release(dst);
 120                         dst = NULL;
 121                 }
 122         }
 123         rcu_read_unlock();
 124         return (struct rtable *)dst;
 125 }
 126
 127 static bool ip_tunnel_key_match(const struct ip_tunnel_parm *p,
 128                                 __be16 flags, __be32 key)
 129 {
 130         if (p->i_flags & TUNNEL_KEY) {
 131                 if (flags & TUNNEL_KEY)
 132                         return key == p->i_key;
 133                 else
 134                         /* key expected, none present */
 135                         return false;
 136         } else
 137                 return !(flags & TUNNEL_KEY);
 138 }
 139
 140 /* Fallback tunnel: no source, no destination, no key, no options
 141
 142    Tunnel hash table:
 143    We require exact key match i.e. if a key is present in packet
 144    it will match only tunnel with the same key; if it is not present,
 145    it will match only keyless tunnel.
 146
 147    All keysless packets, if not matched configured keyless tunnels
 148    will match fallback tunnel.
 149    Given src, dst and key, find appropriate for input tunnel.
 150 */
 151 struct ip_tunnel *ip_tunnel_lookup(struct ip_tunnel_net *itn,
 152                                    int link, __be16 flags,
 153                                    __be32 remote, __be32 local,
 154                                    __be32 key)
 155 {
 156         unsigned int hash;
 157         struct ip_tunnel *t, *cand = NULL;
 158         struct hlist_head *head;
 159
 160         hash = ip_tunnel_hash(key, remote);
 161         head = &itn->tunnels[hash];
 162
 163         hlist_for_each_entry_rcu(t, head, hash_node) {
 164                 if (local != t->parms.iph.saddr ||
 165                     remote != t->parms.iph.daddr ||
 166                     !(t->dev->flags & IFF_UP))
 167                         continue;
 168
 169                 if (!ip_tunnel_key_match(&t->parms, flags, key))
 170                         continue;
 171
 172                 if (t->parms.link == link)
 173                         return t;
 174                 else
 175                         cand = t;
 176         }
 177
 178         hlist_for_each_entry_rcu(t, head, hash_node) {
 179                 if (remote != t->parms.iph.daddr ||
 180                     t->parms.iph.saddr != 0 ||
 181                     !(t->dev->flags & IFF_UP))
 182                         continue;
 183
 184                 if (!ip_tunnel_key_match(&t->parms, flags, key))
 185                         continue;
 186
 187                 if (t->parms.link == link)
 188                         return t;
 189                 else if (!cand)
 190                         cand = t;
 191         }
 192
 193         hash = ip_tunnel_hash(key, 0);
 194         head = &itn->tunnels[hash];
 195
 196         hlist_for_each_entry_rcu(t, head, hash_node) {
 197                 if ((local != t->parms.iph.saddr || t->parms.iph.daddr != 0) &&
 198                     (local != t->parms.iph.daddr || !ipv4_is_multicast(local)))
 199                         continue;
 200
 201                 if (!(t->dev->flags & IFF_UP))
 202                         continue;
 203
 204                 if (!ip_tunnel_key_match(&t->parms, flags, key))
 205                         continue;
 206
 207                 if (t->parms.link == link)
 208                         return t;
 209                 else if (!cand)
 210                         cand = t;
 211         }
 212
 213         if (flags & TUNNEL_NO_KEY)
 214                 goto skip_key_lookup;
 215
 216         hlist_for_each_entry_rcu(t, head, hash_node) {
 217                 if (t->parms.i_key != key ||
 218                     t->parms.iph.saddr != 0 ||
 219                     t->parms.iph.daddr != 0 ||
 220                     !(t->dev->flags & IFF_UP))
 221                         continue;
 222
 223                 if (t->parms.link == link)
 224                         return t;
 225                 else if (!cand)
 226                         cand = t;
 227         }
 228
 229 skip_key_lookup:
 230         if (cand)
 231                 return cand;
 232
 233         if (itn->fb_tunnel_dev && itn->fb_tunnel_dev->flags & IFF_UP)
 234                 return netdev_priv(itn->fb_tunnel_dev);
 235
 236
 237         return NULL;
 238 }
 239 EXPORT_SYMBOL_GPL(ip_tunnel_lookup);
 240
 241 static struct hlist_head *ip_bucket(struct ip_tunnel_net *itn,
 242                                     struct ip_tunnel_parm *parms)
 243 {
 244         unsigned int h;
 245         __be32 remote;
 246         __be32 i_key = parms->i_key;
 247
 248         if (parms->iph.daddr && !ipv4_is_multicast(parms->iph.daddr))
 249                 remote = parms->iph.daddr;
 250         else
 251                 remote = 0;
 252
 253         if (!(parms->i_flags & TUNNEL_KEY) && (parms->i_flags & VTI_ISVTI))
 254                 i_key = 0;
 255
 256         h = ip_tunnel_hash(i_key, remote);
 257         return &itn->tunnels[h];
 258 }
 259
 260 static void ip_tunnel_add(struct ip_tunnel_net *itn, struct ip_tunnel *t)
 261 {
 262         struct hlist_head *head = ip_bucket(itn, &t->parms);
 263
 264         hlist_add_head_rcu(&t->hash_node, head);
 265 }
 266
 267 static void ip_tunnel_del(struct ip_tunnel *t)
 268 {
 269         hlist_del_init_rcu(&t->hash_node);
 270 }
 271
 272 static struct ip_tunnel *ip_tunnel_find(struct ip_tunnel_net *itn,
 273                                         struct ip_tunnel_parm *parms,
 274                                         int type)
 275 {
 276         __be32 remote = parms->iph.daddr;
 277         __be32 local = parms->iph.saddr;
 278         __be32 key = parms->i_key;
 279         __be16 flags = parms->i_flags;
 280         int link = parms->link;
 281         struct ip_tunnel *t = NULL;
 282         struct hlist_head *head = ip_bucket(itn, parms);
 283
 284         hlist_for_each_entry_rcu(t, head, hash_node) {
 285                 if (local == t->parms.iph.saddr &&
 286                     remote == t->parms.iph.daddr &&
 287                     link == t->parms.link &&
 288                     type == t->dev->type &&
 289                     ip_tunnel_key_match(&t->parms, flags, key))
 290                         break;
 291         }
 292         return t;
 293 }
 294
 295 static struct net_device *__ip_tunnel_create(struct net *net,
 296                                              const struct rtnl_link_ops *ops,
 297                                              struct ip_tunnel_parm *parms)
 298 {
 299         int err;
 300         struct ip_tunnel *tunnel;
 301         struct net_device *dev;
 302         char name[IFNAMSIZ];
 303
 304         if (parms->name[0])
 305                 strlcpy(name, parms->name, IFNAMSIZ);
 306         else {
 307                 if (strlen(ops->kind) > (IFNAMSIZ - 3)) {
 308                         err = -E2BIG;
 309                         goto failed;
 310                 }
 311                 strlcpy(name, ops->kind, IFNAMSIZ);
 312                 strncat(name, "%d", 2);
 313         }
 314
 315         ASSERT_RTNL();
 316         dev = alloc_netdev(ops->priv_size, name, NET_NAME_UNKNOWN, ops->setup);
 317         if (!dev) {
 318                 err = -ENOMEM;
 319                 goto failed;
 320         }
 321         dev_net_set(dev, net);
 322
 323         dev->rtnl_link_ops = ops;
 324
 325         tunnel = netdev_priv(dev);
 326         tunnel->parms = *parms;
 327         tunnel->net = net;
 328
 329         err = register_netdevice(dev);
 330         if (err)
 331                 goto failed_free;
 332
 333         return dev;
 334
 335 failed_free:
 336         free_netdev(dev);
 337 failed:
 338         return ERR_PTR(err);
 339 }
 340
 341 static inline void init_tunnel_flow(struct flowi4 *fl4,
 342                                     int proto,
 343                                     __be32 daddr, __be32 saddr,
 344                                     __be32 key, __u8 tos, int oif)
 345 {
 346         memset(fl4, 0, sizeof(*fl4));
 347         fl4->flowi4_oif = oif;
 348         fl4->daddr = daddr;
 349         fl4->saddr = saddr;
 350         fl4->flowi4_tos = tos;
 351         fl4->flowi4_proto = proto;
 352         fl4->fl4_gre_key = key;
 353 }
 354
 355 static int ip_tunnel_bind_dev(struct net_device *dev)
 356 {
 357         struct net_device *tdev = NULL;
 358         struct ip_tunnel *tunnel = netdev_priv(dev);
 359         const struct iphdr *iph;
 360         int hlen = LL_MAX_HEADER;
 361         int mtu = ETH_DATA_LEN;
 362         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 363
 364         iph = &tunnel->parms.iph;
 365
 366         /* Guess output device to choose reasonable mtu and needed_headroom */
 367         if (iph->daddr) {
 368                 struct flowi4 fl4;
 369                 struct rtable *rt;
 370
 371                 init_tunnel_flow(&fl4, iph->protocol, iph->daddr,
 372                                  iph->saddr, tunnel->parms.o_key,
 373                                  RT_TOS(iph->tos), tunnel->parms.link);
 374                 rt = ip_route_output_key(tunnel->net, &fl4);
 375
 376                 if (!IS_ERR(rt)) {
 377                         tdev = rt->dst.dev;
 378                         tunnel_dst_set(tunnel, &rt->dst, fl4.saddr);
 379                         ip_rt_put(rt);
 380                 }
 381                 if (dev->type != ARPHRD_ETHER)
 382                         dev->flags |= IFF_POINTOPOINT;
 383         }
 384
 385         if (!tdev && tunnel->parms.link)
 386                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
 387
 388         if (tdev) {
 389                 hlen = tdev->hard_header_len + tdev->needed_headroom;
 390                 mtu = tdev->mtu;
 391         }
 392         dev->iflink = tunnel->parms.link;
 393
 394         dev->needed_headroom = t_hlen + hlen;
 395         mtu -= (dev->hard_header_len + t_hlen);
 396
 397         if (mtu < 68)
 398                 mtu = 68;
 399
 400         return mtu;
 401 }
 402
 403 static struct ip_tunnel *ip_tunnel_create(struct net *net,
 404                                           struct ip_tunnel_net *itn,
 405                                           struct ip_tunnel_parm *parms)
 406 {
 407         struct ip_tunnel *nt;
 408         struct net_device *dev;
 409
 410         BUG_ON(!itn->fb_tunnel_dev);
 411         dev = __ip_tunnel_create(net, itn->fb_tunnel_dev->rtnl_link_ops, parms);
 412         if (IS_ERR(dev))
 413                 return ERR_CAST(dev);
 414
 415         dev->mtu = ip_tunnel_bind_dev(dev);
 416
 417         nt = netdev_priv(dev);
 418         ip_tunnel_add(itn, nt);
 419         return nt;
 420 }
 421
 422 int ip_tunnel_rcv(struct ip_tunnel *tunnel, struct sk_buff *skb,
 423                   const struct tnl_ptk_info *tpi, bool log_ecn_error)
 424 {
 425         struct pcpu_sw_netstats *tstats;
 426         const struct iphdr *iph = ip_hdr(skb);
 427         int err;
 428
 429 #ifdef CONFIG_NET_IPGRE_BROADCAST
 430         if (ipv4_is_multicast(iph->daddr)) {
 431                 tunnel->dev->stats.multicast++;
 432                 skb->pkt_type = PACKET_BROADCAST;
 433         }
 434 #endif
 435
 436         if ((!(tpi->flags&TUNNEL_CSUM) &&  (tunnel->parms.i_flags&TUNNEL_CSUM)) ||
 437              ((tpi->flags&TUNNEL_CSUM) && !(tunnel->parms.i_flags&TUNNEL_CSUM))) {
 438                 tunnel->dev->stats.rx_crc_errors++;
 439                 tunnel->dev->stats.rx_errors++;
 440                 goto drop;
 441         }
 442
 443         if (tunnel->parms.i_flags&TUNNEL_SEQ) {
 444                 if (!(tpi->flags&TUNNEL_SEQ) ||
 445                     (tunnel->i_seqno && (s32)(ntohl(tpi->seq) - tunnel->i_seqno) < 0)) {
 446                         tunnel->dev->stats.rx_fifo_errors++;
 447                         tunnel->dev->stats.rx_errors++;
 448                         goto drop;
 449                 }
 450                 tunnel->i_seqno = ntohl(tpi->seq) + 1;
 451         }
 452
 453         skb_reset_network_header(skb);
 454
 455         err = IP_ECN_decapsulate(iph, skb);
 456         if (unlikely(err)) {
 457                 if (log_ecn_error)
 458                         net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
 459                                         &iph->saddr, iph->tos);
 460                 if (err > 1) {
 461                         ++tunnel->dev->stats.rx_frame_errors;
 462                         ++tunnel->dev->stats.rx_errors;
 463                         goto drop;
 464                 }
 465         }
 466
 467         tstats = this_cpu_ptr(tunnel->dev->tstats);
 468         u64_stats_update_begin(&tstats->syncp);
 469         tstats->rx_packets++;
 470         tstats->rx_bytes += skb->len;
 471         u64_stats_update_end(&tstats->syncp);
 472
 473         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(tunnel->dev)));
 474
 475         if (tunnel->dev->type == ARPHRD_ETHER) {
 476                 skb->protocol = eth_type_trans(skb, tunnel->dev);
 477                 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
 478         } else {
 479                 skb->dev = tunnel->dev;
 480         }
 481
 482         gro_cells_receive(&tunnel->gro_cells, skb);
 483         return 0;
 484
 485 drop:
 486         kfree_skb(skb);
 487         return 0;
 488 }
 489 EXPORT_SYMBOL_GPL(ip_tunnel_rcv);
 490
 491 static int ip_encap_hlen(struct ip_tunnel_encap *e)
 492 {
 493         const struct ip_tunnel_encap_ops *ops;
 494         int hlen = -EINVAL;
 495
 496         if (e->type == TUNNEL_ENCAP_NONE)
 497                 return 0;
 498
 499         if (e->type >= MAX_IPTUN_ENCAP_OPS)
 500                 return -EINVAL;
 501
 502         rcu_read_lock();
 503         ops = rcu_dereference(iptun_encaps[e->type]);
 504         if (likely(ops && ops->encap_hlen))
 505                 hlen = ops->encap_hlen(e);
 506         rcu_read_unlock();
 507
 508         return hlen;
 509 }
 510
 511 const struct ip_tunnel_encap_ops __rcu *
 512                 iptun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
 513
 514 int ip_tunnel_encap_add_ops(const struct ip_tunnel_encap_ops *ops,
 515                             unsigned int num)
 516 {
 517         if (num >= MAX_IPTUN_ENCAP_OPS)
 518                 return -ERANGE;
 519
 520         return !cmpxchg((const struct ip_tunnel_encap_ops **)
 521                         &iptun_encaps[num],
 522                         NULL, ops) ? 0 : -1;
 523 }
 524 EXPORT_SYMBOL(ip_tunnel_encap_add_ops);
 525
 526 int ip_tunnel_encap_del_ops(const struct ip_tunnel_encap_ops *ops,
 527                             unsigned int num)
 528 {
 529         int ret;
 530
 531         if (num >= MAX_IPTUN_ENCAP_OPS)
 532                 return -ERANGE;
 533
 534         ret = (cmpxchg((const struct ip_tunnel_encap_ops **)
 535                        &iptun_encaps[num],
 536                        ops, NULL) == ops) ? 0 : -1;
 537
 538         synchronize_net();
 539
 540         return ret;
 541 }
 542 EXPORT_SYMBOL(ip_tunnel_encap_del_ops);
 543
 544 int ip_tunnel_encap_setup(struct ip_tunnel *t,
 545                           struct ip_tunnel_encap *ipencap)
 546 {
 547         int hlen;
 548
 549         memset(&t->encap, 0, sizeof(t->encap));
 550
 551         hlen = ip_encap_hlen(ipencap);
 552         if (hlen < 0)
 553                 return hlen;
 554
 555         t->encap.type = ipencap->type;
 556         t->encap.sport = ipencap->sport;
 557         t->encap.dport = ipencap->dport;
 558         t->encap.flags = ipencap->flags;
 559
 560         t->encap_hlen = hlen;
 561         t->hlen = t->encap_hlen + t->tun_hlen;
 562
 563         return 0;
 564 }
 565 EXPORT_SYMBOL_GPL(ip_tunnel_encap_setup);
 566
 567 int ip_tunnel_encap(struct sk_buff *skb, struct ip_tunnel *t,
 568                     u8 *protocol, struct flowi4 *fl4)
 569 {
 570         const struct ip_tunnel_encap_ops *ops;
 571         int ret = -EINVAL;
 572
 573         if (t->encap.type == TUNNEL_ENCAP_NONE)
 574                 return 0;
 575
 576         if (t->encap.type >= MAX_IPTUN_ENCAP_OPS)
 577                 return -EINVAL;
 578
 579         rcu_read_lock();
 580         ops = rcu_dereference(iptun_encaps[t->encap.type]);
 581         if (likely(ops && ops->build_header))
 582                 ret = ops->build_header(skb, &t->encap, protocol, fl4);
 583         rcu_read_unlock();
 584
 585         return ret;
 586 }
 587 EXPORT_SYMBOL(ip_tunnel_encap);
 588
 589 static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
 590                             struct rtable *rt, __be16 df)
 591 {
 592         struct ip_tunnel *tunnel = netdev_priv(dev);
 593         int pkt_size = skb->len - tunnel->hlen - dev->hard_header_len;
 594         int mtu;
 595
 596         if (df)
 597                 mtu = dst_mtu(&rt->dst) - dev->hard_header_len
 598                                         - sizeof(struct iphdr) - tunnel->hlen;
 599         else
 600                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
 601
 602         if (skb_dst(skb))
 603                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
 604
 605         if (skb->protocol == htons(ETH_P_IP)) {
 606                 if (!skb_is_gso(skb) &&
 607                     (df & htons(IP_DF)) && mtu < pkt_size) {
 608                         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 609                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
 610                         return -E2BIG;
 611                 }
 612         }
 613 #if IS_ENABLED(CONFIG_IPV6)
 614         else if (skb->protocol == htons(ETH_P_IPV6)) {
 615                 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
 616
 617                 if (rt6 && mtu < dst_mtu(skb_dst(skb)) &&
 618                            mtu >= IPV6_MIN_MTU) {
 619                         if ((tunnel->parms.iph.daddr &&
 620                             !ipv4_is_multicast(tunnel->parms.iph.daddr)) ||
 621                             rt6->rt6i_dst.plen == 128) {
 622                                 rt6->rt6i_flags |= RTF_MODIFIED;
 623                                 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu);
 624                         }
 625                 }
 626
 627                 if (!skb_is_gso(skb) && mtu >= IPV6_MIN_MTU &&
 628                                         mtu < pkt_size) {
 629                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
 630                         return -E2BIG;
 631                 }
 632         }
 633 #endif
 634         return 0;
 635 }
 636
 637 void ip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev,
 638                     const struct iphdr *tnl_params, u8 protocol)
 639 {
 640         struct ip_tunnel *tunnel = netdev_priv(dev);
 641         const struct iphdr *inner_iph;
 642         struct flowi4 fl4;
 643         u8     tos, ttl;
 644         __be16 df;
 645         struct rtable *rt;              /* Route to the other host */
 646         unsigned int max_headroom;      /* The extra header space needed */
 647         __be32 dst;
 648         int err;
 649         bool connected;
 650
 651         inner_iph = (const struct iphdr *)skb_inner_network_header(skb);
 652         connected = (tunnel->parms.iph.daddr != 0);
 653
 654         dst = tnl_params->daddr;
 655         if (dst == 0) {
 656                 /* NBMA tunnel */
 657
 658                 if (skb_dst(skb) == NULL) {
 659                         dev->stats.tx_fifo_errors++;
 660                         goto tx_error;
 661                 }
 662
 663                 if (skb->protocol == htons(ETH_P_IP)) {
 664                         rt = skb_rtable(skb);
 665                         dst = rt_nexthop(rt, inner_iph->daddr);
 666                 }
 667 #if IS_ENABLED(CONFIG_IPV6)
 668                 else if (skb->protocol == htons(ETH_P_IPV6)) {
 669                         const struct in6_addr *addr6;
 670                         struct neighbour *neigh;
 671                         bool do_tx_error_icmp;
 672                         int addr_type;
 673
 674                         neigh = dst_neigh_lookup(skb_dst(skb),
 675                                                  &ipv6_hdr(skb)->daddr);
 676                         if (neigh == NULL)
 677                                 goto tx_error;
 678
 679                         addr6 = (const struct in6_addr *)&neigh->primary_key;
 680                         addr_type = ipv6_addr_type(addr6);
 681
 682                         if (addr_type == IPV6_ADDR_ANY) {
 683                                 addr6 = &ipv6_hdr(skb)->daddr;
 684                                 addr_type = ipv6_addr_type(addr6);
 685                         }
 686
 687                         if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
 688                                 do_tx_error_icmp = true;
 689                         else {
 690                                 do_tx_error_icmp = false;
 691                                 dst = addr6->s6_addr32[3];
 692                         }
 693                         neigh_release(neigh);
 694                         if (do_tx_error_icmp)
 695                                 goto tx_error_icmp;
 696                 }
 697 #endif
 698                 else
 699                         goto tx_error;
 700
 701                 connected = false;
 702         }
 703
 704         tos = tnl_params->tos;
 705         if (tos & 0x1) {
 706                 tos &= ~0x1;
 707                 if (skb->protocol == htons(ETH_P_IP)) {
 708                         tos = inner_iph->tos;
 709                         connected = false;
 710                 } else if (skb->protocol == htons(ETH_P_IPV6)) {
 711                         tos = ipv6_get_dsfield((const struct ipv6hdr *)inner_iph);
 712                         connected = false;
 713                 }
 714         }
 715
 716         init_tunnel_flow(&fl4, protocol, dst, tnl_params->saddr,
 717                          tunnel->parms.o_key, RT_TOS(tos), tunnel->parms.link);
 718
 719         if (ip_tunnel_encap(skb, tunnel, &protocol, &fl4) < 0)
 720                 goto tx_error;
 721
 722         rt = connected ? tunnel_rtable_get(tunnel, 0, &fl4.saddr) : NULL;
 723
 724         if (!rt) {
 725                 rt = ip_route_output_key(tunnel->net, &fl4);
 726
 727                 if (IS_ERR(rt)) {
 728                         dev->stats.tx_carrier_errors++;
 729                         goto tx_error;
 730                 }
 731                 if (connected)
 732                         tunnel_dst_set(tunnel, &rt->dst, fl4.saddr);
 733         }
 734
 735         if (rt->dst.dev == dev) {
 736                 ip_rt_put(rt);
 737                 dev->stats.collisions++;
 738                 goto tx_error;
 739         }
 740
 741         if (tnl_update_pmtu(dev, skb, rt, tnl_params->frag_off)) {
 742                 ip_rt_put(rt);
 743                 goto tx_error;
 744         }
 745
 746         if (tunnel->err_count > 0) {
 747                 if (time_before(jiffies,
 748                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 749                         tunnel->err_count--;
 750
 751                         memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 752                         dst_link_failure(skb);
 753                 } else
 754                         tunnel->err_count = 0;
 755         }
 756
 757         tos = ip_tunnel_ecn_encap(tos, inner_iph, skb);
 758         ttl = tnl_params->ttl;
 759         if (ttl == 0) {
 760                 if (skb->protocol == htons(ETH_P_IP))
 761                         ttl = inner_iph->ttl;
 762 #if IS_ENABLED(CONFIG_IPV6)
 763                 else if (skb->protocol == htons(ETH_P_IPV6))
 764                         ttl = ((const struct ipv6hdr *)inner_iph)->hop_limit;
 765 #endif
 766                 else
 767                         ttl = ip4_dst_hoplimit(&rt->dst);
 768         }
 769
 770         df = tnl_params->frag_off;
 771         if (skb->protocol == htons(ETH_P_IP))
 772                 df |= (inner_iph->frag_off&htons(IP_DF));
 773
 774         max_headroom = LL_RESERVED_SPACE(rt->dst.dev) + sizeof(struct iphdr)
 775                         + rt->dst.header_len + ip_encap_hlen(&tunnel->encap);
 776         if (max_headroom > dev->needed_headroom)
 777                 dev->needed_headroom = max_headroom;
 778
 779         if (skb_cow_head(skb, dev->needed_headroom)) {
 780                 ip_rt_put(rt);
 781                 dev->stats.tx_dropped++;
 782                 kfree_skb(skb);
 783                 return;
 784         }
 785
 786         err = iptunnel_xmit(skb->sk, rt, skb, fl4.saddr, fl4.daddr, protocol,
 787                             tos, ttl, df, !net_eq(tunnel->net, dev_net(dev)));
 788         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 789
 790         return;
 791
 792 #if IS_ENABLED(CONFIG_IPV6)
 793 tx_error_icmp:
 794         dst_link_failure(skb);
 795 #endif
 796 tx_error:
 797         dev->stats.tx_errors++;
 798         kfree_skb(skb);
 799 }
 800 EXPORT_SYMBOL_GPL(ip_tunnel_xmit);
 801
 802 static void ip_tunnel_update(struct ip_tunnel_net *itn,
 803                              struct ip_tunnel *t,
 804                              struct net_device *dev,
 805                              struct ip_tunnel_parm *p,
 806                              bool set_mtu)
 807 {
 808         ip_tunnel_del(t);
 809         t->parms.iph.saddr = p->iph.saddr;
 810         t->parms.iph.daddr = p->iph.daddr;
 811         t->parms.i_key = p->i_key;
 812         t->parms.o_key = p->o_key;
 813         if (dev->type != ARPHRD_ETHER) {
 814                 memcpy(dev->dev_addr, &p->iph.saddr, 4);
 815                 memcpy(dev->broadcast, &p->iph.daddr, 4);
 816         }
 817         ip_tunnel_add(itn, t);
 818
 819         t->parms.iph.ttl = p->iph.ttl;
 820         t->parms.iph.tos = p->iph.tos;
 821         t->parms.iph.frag_off = p->iph.frag_off;
 822
 823         if (t->parms.link != p->link) {
 824                 int mtu;
 825
 826                 t->parms.link = p->link;
 827                 mtu = ip_tunnel_bind_dev(dev);
 828                 if (set_mtu)
 829                         dev->mtu = mtu;
 830         }
 831         ip_tunnel_dst_reset_all(t);
 832         netdev_state_change(dev);
 833 }
 834
 835 int ip_tunnel_ioctl(struct net_device *dev, struct ip_tunnel_parm *p, int cmd)
 836 {
 837         int err = 0;
 838         struct ip_tunnel *t = netdev_priv(dev);
 839         struct net *net = t->net;
 840         struct ip_tunnel_net *itn = net_generic(net, t->ip_tnl_net_id);
 841
 842         BUG_ON(!itn->fb_tunnel_dev);
 843         switch (cmd) {
 844         case SIOCGETTUNNEL:
 845                 if (dev == itn->fb_tunnel_dev) {
 846                         t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
 847                         if (t == NULL)
 848                                 t = netdev_priv(dev);
 849                 }
 850                 memcpy(p, &t->parms, sizeof(*p));
 851                 break;
 852
 853         case SIOCADDTUNNEL:
 854         case SIOCCHGTUNNEL:
 855                 err = -EPERM;
 856                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 857                         goto done;
 858                 if (p->iph.ttl)
 859                         p->iph.frag_off |= htons(IP_DF);
 860                 if (!(p->i_flags & VTI_ISVTI)) {
 861                         if (!(p->i_flags & TUNNEL_KEY))
 862                                 p->i_key = 0;
 863                         if (!(p->o_flags & TUNNEL_KEY))
 864                                 p->o_key = 0;
 865                 }
 866
 867                 t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
 868
 869                 if (cmd == SIOCADDTUNNEL) {
 870                         if (!t) {
 871                                 t = ip_tunnel_create(net, itn, p);
 872                                 err = PTR_ERR_OR_ZERO(t);
 873                                 break;
 874                         }
 875
 876                         err = -EEXIST;
 877                         break;
 878                 }
 879                 if (dev != itn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
 880                         if (t != NULL) {
 881                                 if (t->dev != dev) {
 882                                         err = -EEXIST;
 883                                         break;
 884                                 }
 885                         } else {
 886                                 unsigned int nflags = 0;
 887
 888                                 if (ipv4_is_multicast(p->iph.daddr))
 889                                         nflags = IFF_BROADCAST;
 890                                 else if (p->iph.daddr)
 891                                         nflags = IFF_POINTOPOINT;
 892
 893                                 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) {
 894                                         err = -EINVAL;
 895                                         break;
 896                                 }
 897
 898                                 t = netdev_priv(dev);
 899                         }
 900                 }
 901
 902                 if (t) {
 903                         err = 0;
 904                         ip_tunnel_update(itn, t, dev, p, true);
 905                 } else {
 906                         err = -ENOENT;
 907                 }
 908                 break;
 909
 910         case SIOCDELTUNNEL:
 911                 err = -EPERM;
 912                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
 913                         goto done;
 914
 915                 if (dev == itn->fb_tunnel_dev) {
 916                         err = -ENOENT;
 917                         t = ip_tunnel_find(itn, p, itn->fb_tunnel_dev->type);
 918                         if (t == NULL)
 919                                 goto done;
 920                         err = -EPERM;
 921                         if (t == netdev_priv(itn->fb_tunnel_dev))
 922                                 goto done;
 923                         dev = t->dev;
 924                 }
 925                 unregister_netdevice(dev);
 926                 err = 0;
 927                 break;
 928
 929         default:
 930                 err = -EINVAL;
 931         }
 932
 933 done:
 934         return err;
 935 }
 936 EXPORT_SYMBOL_GPL(ip_tunnel_ioctl);
 937
 938 int ip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
 939 {
 940         struct ip_tunnel *tunnel = netdev_priv(dev);
 941         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
 942
 943         if (new_mtu < 68 ||
 944             new_mtu > 0xFFF8 - dev->hard_header_len - t_hlen)
 945                 return -EINVAL;
 946         dev->mtu = new_mtu;
 947         return 0;
 948 }
 949 EXPORT_SYMBOL_GPL(ip_tunnel_change_mtu);
 950
 951 static void ip_tunnel_dev_free(struct net_device *dev)
 952 {
 953         struct ip_tunnel *tunnel = netdev_priv(dev);
 954
 955         gro_cells_destroy(&tunnel->gro_cells);
 956         free_percpu(tunnel->dst_cache);
 957         free_percpu(dev->tstats);
 958         free_netdev(dev);
 959 }
 960
 961 void ip_tunnel_dellink(struct net_device *dev, struct list_head *head)
 962 {
 963         struct ip_tunnel *tunnel = netdev_priv(dev);
 964         struct ip_tunnel_net *itn;
 965
 966         itn = net_generic(tunnel->net, tunnel->ip_tnl_net_id);
 967
 968         if (itn->fb_tunnel_dev != dev) {
 969                 ip_tunnel_del(netdev_priv(dev));
 970                 unregister_netdevice_queue(dev, head);
 971         }
 972 }
 973 EXPORT_SYMBOL_GPL(ip_tunnel_dellink);
 974
 975 int ip_tunnel_init_net(struct net *net, int ip_tnl_net_id,
 976                                   struct rtnl_link_ops *ops, char *devname)
 977 {
 978         struct ip_tunnel_net *itn = net_generic(net, ip_tnl_net_id);
 979         struct ip_tunnel_parm parms;
 980         unsigned int i;
 981
 982         for (i = 0; i < IP_TNL_HASH_SIZE; i++)
 983                 INIT_HLIST_HEAD(&itn->tunnels[i]);
 984
 985         if (!ops) {
 986                 itn->fb_tunnel_dev = NULL;
 987                 return 0;
 988         }
 989
 990         memset(&parms, 0, sizeof(parms));
 991         if (devname)
 992                 strlcpy(parms.name, devname, IFNAMSIZ);
 993
 994         rtnl_lock();
 995         itn->fb_tunnel_dev = __ip_tunnel_create(net, ops, &parms);
 996         /* FB netdevice is special: we have one, and only one per netns.
 997          * Allowing to move it to another netns is clearly unsafe.
 998          */
 999         if (!IS_ERR(itn->fb_tunnel_dev)) {
1000                 itn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1001                 itn->fb_tunnel_dev->mtu = ip_tunnel_bind_dev(itn->fb_tunnel_dev);
1002                 ip_tunnel_add(itn, netdev_priv(itn->fb_tunnel_dev));
1003         }
1004         rtnl_unlock();
1005
1006         return PTR_ERR_OR_ZERO(itn->fb_tunnel_dev);
1007 }
1008 EXPORT_SYMBOL_GPL(ip_tunnel_init_net);
1009
1010 static void ip_tunnel_destroy(struct ip_tunnel_net *itn, struct list_head *head,
1011                               struct rtnl_link_ops *ops)
1012 {
1013         struct net *net = dev_net(itn->fb_tunnel_dev);
1014         struct net_device *dev, *aux;
1015         int h;
1016
1017         for_each_netdev_safe(net, dev, aux)
1018                 if (dev->rtnl_link_ops == ops)
1019                         unregister_netdevice_queue(dev, head);
1020
1021         for (h = 0; h < IP_TNL_HASH_SIZE; h++) {
1022                 struct ip_tunnel *t;
1023                 struct hlist_node *n;
1024                 struct hlist_head *thead = &itn->tunnels[h];
1025
1026                 hlist_for_each_entry_safe(t, n, thead, hash_node)
1027                         /* If dev is in the same netns, it has already
1028                          * been added to the list by the previous loop.
1029                          */
1030                         if (!net_eq(dev_net(t->dev), net))
1031                                 unregister_netdevice_queue(t->dev, head);
1032         }
1033 }
1034
1035 void ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops)
1036 {
1037         LIST_HEAD(list);
1038
1039         rtnl_lock();
1040         ip_tunnel_destroy(itn, &list, ops);
1041         unregister_netdevice_many(&list);
1042         rtnl_unlock();
1043 }
1044 EXPORT_SYMBOL_GPL(ip_tunnel_delete_net);
1045
1046 int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
1047                       struct ip_tunnel_parm *p)
1048 {
1049         struct ip_tunnel *nt;
1050         struct net *net = dev_net(dev);
1051         struct ip_tunnel_net *itn;
1052         int mtu;
1053         int err;
1054
1055         nt = netdev_priv(dev);
1056         itn = net_generic(net, nt->ip_tnl_net_id);
1057
1058         if (ip_tunnel_find(itn, p, dev->type))
1059                 return -EEXIST;
1060
1061         nt->net = net;
1062         nt->parms = *p;
1063         err = register_netdevice(dev);
1064         if (err)
1065                 goto out;
1066
1067         if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS])
1068                 eth_hw_addr_random(dev);
1069
1070         mtu = ip_tunnel_bind_dev(dev);
1071         if (!tb[IFLA_MTU])
1072                 dev->mtu = mtu;
1073
1074         ip_tunnel_add(itn, nt);
1075
1076 out:
1077         return err;
1078 }
1079 EXPORT_SYMBOL_GPL(ip_tunnel_newlink);
1080
1081 int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
1082                          struct ip_tunnel_parm *p)
1083 {
1084         struct ip_tunnel *t;
1085         struct ip_tunnel *tunnel = netdev_priv(dev);
1086         struct net *net = tunnel->net;
1087         struct ip_tunnel_net *itn = net_generic(net, tunnel->ip_tnl_net_id);
1088
1089         if (dev == itn->fb_tunnel_dev)
1090                 return -EINVAL;
1091
1092         t = ip_tunnel_find(itn, p, dev->type);
1093
1094         if (t) {
1095                 if (t->dev != dev)
1096                         return -EEXIST;
1097         } else {
1098                 t = tunnel;
1099
1100                 if (dev->type != ARPHRD_ETHER) {
1101                         unsigned int nflags = 0;
1102
1103                         if (ipv4_is_multicast(p->iph.daddr))
1104                                 nflags = IFF_BROADCAST;
1105                         else if (p->iph.daddr)
1106                                 nflags = IFF_POINTOPOINT;
1107
1108                         if ((dev->flags ^ nflags) &
1109                             (IFF_POINTOPOINT | IFF_BROADCAST))
1110                                 return -EINVAL;
1111                 }
1112         }
1113
1114         ip_tunnel_update(itn, t, dev, p, !tb[IFLA_MTU]);
1115         return 0;
1116 }
1117 EXPORT_SYMBOL_GPL(ip_tunnel_changelink);
1118
1119 int ip_tunnel_init(struct net_device *dev)
1120 {
1121         struct ip_tunnel *tunnel = netdev_priv(dev);
1122         struct iphdr *iph = &tunnel->parms.iph;
1123         int err;
1124
1125         dev->destructor = ip_tunnel_dev_free;
1126         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1127         if (!dev->tstats)
1128                 return -ENOMEM;
1129
1130         tunnel->dst_cache = alloc_percpu(struct ip_tunnel_dst);
1131         if (!tunnel->dst_cache) {
1132                 free_percpu(dev->tstats);
1133                 return -ENOMEM;
1134         }
1135
1136         err = gro_cells_init(&tunnel->gro_cells, dev);
1137         if (err) {
1138                 free_percpu(tunnel->dst_cache);
1139                 free_percpu(dev->tstats);
1140                 return err;
1141         }
1142
1143         tunnel->dev = dev;
1144         tunnel->net = dev_net(dev);
1145         strcpy(tunnel->parms.name, dev->name);
1146         iph->version            = 4;
1147         iph->ihl                = 5;
1148
1149         return 0;
1150 }
1151 EXPORT_SYMBOL_GPL(ip_tunnel_init);
1152
1153 void ip_tunnel_uninit(struct net_device *dev)
1154 {
1155         struct ip_tunnel *tunnel = netdev_priv(dev);
1156         struct net *net = tunnel->net;
1157         struct ip_tunnel_net *itn;
1158
1159         itn = net_generic(net, tunnel->ip_tnl_net_id);
1160         /* fb_tunnel_dev will be unregisted in net-exit call. */
1161         if (itn->fb_tunnel_dev != dev)
1162                 ip_tunnel_del(netdev_priv(dev));
1163
1164         ip_tunnel_dst_reset_all(tunnel);
1165 }
1166 EXPORT_SYMBOL_GPL(ip_tunnel_uninit);
1167
1168 /* Do least required initialization, rest of init is done in tunnel_init call */
1169 void ip_tunnel_setup(struct net_device *dev, int net_id)
1170 {
1171         struct ip_tunnel *tunnel = netdev_priv(dev);
1172         tunnel->ip_tnl_net_id = net_id;
1173 }
1174 EXPORT_SYMBOL_GPL(ip_tunnel_setup);
1175
1176 MODULE_LICENSE("GPL");