net/ipv4/ip_vti.c

   1 /*
   2  *      Linux NET3: IP/IP protocol decoder modified to support
   3  *                  virtual tunnel interface
   4  *
   5  *      Authors:
   6  *              Saurabh Mohan (saurabh.mohan@vyatta.com) 05/07/2012
   7  *
   8  *      This program is free software; you can redistribute it and/or
   9  *      modify it under the terms of the GNU General Public License
  10  *      as published by the Free Software Foundation; either version
  11  *      2 of the License, or (at your option) any later version.
  12  *
  13  */
  14
  15 /*
  16    This version of net/ipv4/ip_vti.c is cloned of net/ipv4/ipip.c
  17
  18    For comments look at net/ipv4/ip_gre.c --ANK
  19  */
  20
  21
  22 #include <linux/capability.h>
  23 #include <linux/module.h>
  24 #include <linux/types.h>
  25 #include <linux/kernel.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/netfilter_ipv4.h>
  36 #include <linux/if_ether.h>
  37 #include <linux/icmpv6.h>
  38
  39 #include <net/sock.h>
  40 #include <net/ip.h>
  41 #include <net/icmp.h>
  42 #include <net/ip_tunnels.h>
  43 #include <net/inet_ecn.h>
  44 #include <net/xfrm.h>
  45 #include <net/net_namespace.h>
  46 #include <net/netns/generic.h>
  47
  48 static struct rtnl_link_ops vti_link_ops __read_mostly;
  49
  50 static int vti_net_id __read_mostly;
  51 static int vti_tunnel_init(struct net_device *dev);
  52
  53 static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi,
  54                      int encap_type)
  55 {
  56         struct ip_tunnel *tunnel;
  57         const struct iphdr *iph = ip_hdr(skb);
  58         struct net *net = dev_net(skb->dev);
  59         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
  60
  61         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
  62                                   iph->saddr, iph->daddr, 0);
  63         if (tunnel != NULL) {
  64                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
  65                         goto drop;
  66
  67                 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel;
  68                 skb->mark = be32_to_cpu(tunnel->parms.i_key);
  69
  70                 return xfrm_input(skb, nexthdr, spi, encap_type);
  71         }
  72
  73         return -EINVAL;
  74 drop:
  75         kfree_skb(skb);
  76         return 0;
  77 }
  78
  79 static int vti_rcv(struct sk_buff *skb)
  80 {
  81         XFRM_SPI_SKB_CB(skb)->family = AF_INET;
  82         XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
  83
  84         return vti_input(skb, ip_hdr(skb)->protocol, 0, 0);
  85 }
  86
  87 static int vti_rcv_cb(struct sk_buff *skb, int err)
  88 {
  89         unsigned short family;
  90         struct net_device *dev;
  91         struct pcpu_sw_netstats *tstats;
  92         struct xfrm_state *x;
  93         struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4;
  94
  95         if (!tunnel)
  96                 return 1;
  97
  98         dev = tunnel->dev;
  99
 100         if (err) {
 101                 dev->stats.rx_errors++;
 102                 dev->stats.rx_dropped++;
 103
 104                 return 0;
 105         }
 106
 107         x = xfrm_input_state(skb);
 108         family = x->inner_mode->afinfo->family;
 109
 110         if (!xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family))
 111                 return -EPERM;
 112
 113         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev)));
 114         skb->dev = dev;
 115
 116         tstats = this_cpu_ptr(dev->tstats);
 117
 118         u64_stats_update_begin(&tstats->syncp);
 119         tstats->rx_packets++;
 120         tstats->rx_bytes += skb->len;
 121         u64_stats_update_end(&tstats->syncp);
 122
 123         return 0;
 124 }
 125
 126 static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src)
 127 {
 128         xfrm_address_t *daddr = (xfrm_address_t *)&dst;
 129         xfrm_address_t *saddr = (xfrm_address_t *)&src;
 130
 131         /* if there is no transform then this tunnel is not functional.
 132          * Or if the xfrm is not mode tunnel.
 133          */
 134         if (!x || x->props.mode != XFRM_MODE_TUNNEL ||
 135             x->props.family != AF_INET)
 136                 return false;
 137
 138         if (!dst)
 139                 return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET);
 140
 141         if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET))
 142                 return false;
 143
 144         return true;
 145 }
 146
 147 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev,
 148                             struct flowi *fl)
 149 {
 150         struct ip_tunnel *tunnel = netdev_priv(dev);
 151         struct ip_tunnel_parm *parms = &tunnel->parms;
 152         struct dst_entry *dst = skb_dst(skb);
 153         struct net_device *tdev;        /* Device to other host */
 154         int err;
 155
 156         if (!dst) {
 157                 dev->stats.tx_carrier_errors++;
 158                 goto tx_error_icmp;
 159         }
 160
 161         dst_hold(dst);
 162         dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0);
 163         if (IS_ERR(dst)) {
 164                 dev->stats.tx_carrier_errors++;
 165                 goto tx_error_icmp;
 166         }
 167
 168         if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) {
 169                 dev->stats.tx_carrier_errors++;
 170                 dst_release(dst);
 171                 goto tx_error_icmp;
 172         }
 173
 174         tdev = dst->dev;
 175
 176         if (tdev == dev) {
 177                 dst_release(dst);
 178                 dev->stats.collisions++;
 179                 goto tx_error;
 180         }
 181
 182         if (tunnel->err_count > 0) {
 183                 if (time_before(jiffies,
 184                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
 185                         tunnel->err_count--;
 186                         dst_link_failure(skb);
 187                 } else
 188                         tunnel->err_count = 0;
 189         }
 190
 191         skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev)));
 192         skb_dst_set(skb, dst);
 193         skb->dev = skb_dst(skb)->dev;
 194
 195         err = dst_output(skb);
 196         if (net_xmit_eval(err) == 0)
 197                 err = skb->len;
 198         iptunnel_xmit_stats(err, &dev->stats, dev->tstats);
 199         return NETDEV_TX_OK;
 200
 201 tx_error_icmp:
 202         dst_link_failure(skb);
 203 tx_error:
 204         dev->stats.tx_errors++;
 205         kfree_skb(skb);
 206         return NETDEV_TX_OK;
 207 }
 208
 209 /* This function assumes it is being called from dev_queue_xmit()
 210  * and that skb is filled properly by that function.
 211  */
 212 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
 213 {
 214         struct ip_tunnel *tunnel = netdev_priv(dev);
 215         struct flowi fl;
 216
 217         memset(&fl, 0, sizeof(fl));
 218
 219         skb->mark = be32_to_cpu(tunnel->parms.o_key);
 220
 221         switch (skb->protocol) {
 222         case htons(ETH_P_IP):
 223                 xfrm_decode_session(skb, &fl, AF_INET);
 224                 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 225                 break;
 226         case htons(ETH_P_IPV6):
 227                 xfrm_decode_session(skb, &fl, AF_INET6);
 228                 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
 229                 break;
 230         default:
 231                 dev->stats.tx_errors++;
 232                 dev_kfree_skb(skb);
 233                 return NETDEV_TX_OK;
 234         }
 235
 236         return vti_xmit(skb, dev, &fl);
 237 }
 238
 239 static int vti4_err(struct sk_buff *skb, u32 info)
 240 {
 241         __be32 spi;
 242         struct xfrm_state *x;
 243         struct ip_tunnel *tunnel;
 244         struct ip_esp_hdr *esph;
 245         struct ip_auth_hdr *ah ;
 246         struct ip_comp_hdr *ipch;
 247         struct net *net = dev_net(skb->dev);
 248         const struct iphdr *iph = (const struct iphdr *)skb->data;
 249         int protocol = iph->protocol;
 250         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 251
 252         tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY,
 253                                   iph->daddr, iph->saddr, 0);
 254         if (!tunnel)
 255                 return -1;
 256
 257         switch (protocol) {
 258         case IPPROTO_ESP:
 259                 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2));
 260                 spi = esph->spi;
 261                 break;
 262         case IPPROTO_AH:
 263                 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2));
 264                 spi = ah->spi;
 265                 break;
 266         case IPPROTO_COMP:
 267                 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2));
 268                 spi = htonl(ntohs(ipch->cpi));
 269                 break;
 270         default:
 271                 return 0;
 272         }
 273
 274         switch (icmp_hdr(skb)->type) {
 275         case ICMP_DEST_UNREACH:
 276                 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED)
 277                         return 0;
 278         case ICMP_REDIRECT:
 279                 break;
 280         default:
 281                 return 0;
 282         }
 283
 284         x = xfrm_state_lookup(net, skb->mark, (const xfrm_address_t *)&iph->daddr,
 285                               spi, protocol, AF_INET);
 286         if (!x)
 287                 return 0;
 288
 289         if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH)
 290                 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0);
 291         else
 292                 ipv4_redirect(skb, net, 0, 0, protocol, 0);
 293         xfrm_state_put(x);
 294
 295         return 0;
 296 }
 297
 298 static int
 299 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 300 {
 301         int err = 0;
 302         struct ip_tunnel_parm p;
 303
 304         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
 305                 return -EFAULT;
 306
 307         if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) {
 308                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
 309                     p.iph.ihl != 5)
 310                         return -EINVAL;
 311         }
 312
 313         p.i_flags |= VTI_ISVTI;
 314         err = ip_tunnel_ioctl(dev, &p, cmd);
 315         if (err)
 316                 return err;
 317
 318         if (cmd != SIOCDELTUNNEL) {
 319                 p.i_flags |= GRE_KEY;
 320                 p.o_flags |= GRE_KEY;
 321         }
 322
 323         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
 324                 return -EFAULT;
 325         return 0;
 326 }
 327
 328 static const struct net_device_ops vti_netdev_ops = {
 329         .ndo_init       = vti_tunnel_init,
 330         .ndo_uninit     = ip_tunnel_uninit,
 331         .ndo_start_xmit = vti_tunnel_xmit,
 332         .ndo_do_ioctl   = vti_tunnel_ioctl,
 333         .ndo_change_mtu = ip_tunnel_change_mtu,
 334         .ndo_get_stats64 = ip_tunnel_get_stats64,
 335 };
 336
 337 static void vti_tunnel_setup(struct net_device *dev)
 338 {
 339         dev->netdev_ops         = &vti_netdev_ops;
 340         dev->type               = ARPHRD_TUNNEL;
 341         ip_tunnel_setup(dev, vti_net_id);
 342 }
 343
 344 static int vti_tunnel_init(struct net_device *dev)
 345 {
 346         struct ip_tunnel *tunnel = netdev_priv(dev);
 347         struct iphdr *iph = &tunnel->parms.iph;
 348
 349         memcpy(dev->dev_addr, &iph->saddr, 4);
 350         memcpy(dev->broadcast, &iph->daddr, 4);
 351
 352         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
 353         dev->mtu                = ETH_DATA_LEN;
 354         dev->flags              = IFF_NOARP;
 355         dev->iflink             = 0;
 356         dev->addr_len           = 4;
 357         dev->features           |= NETIF_F_LLTX;
 358         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
 359
 360         return ip_tunnel_init(dev);
 361 }
 362
 363 static void __net_init vti_fb_tunnel_init(struct net_device *dev)
 364 {
 365         struct ip_tunnel *tunnel = netdev_priv(dev);
 366         struct iphdr *iph = &tunnel->parms.iph;
 367
 368         iph->version            = 4;
 369         iph->protocol           = IPPROTO_IPIP;
 370         iph->ihl                = 5;
 371 }
 372
 373 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = {
 374         .handler        =       vti_rcv,
 375         .input_handler  =       vti_input,
 376         .cb_handler     =       vti_rcv_cb,
 377         .err_handler    =       vti4_err,
 378         .priority       =       100,
 379 };
 380
 381 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = {
 382         .handler        =       vti_rcv,
 383         .input_handler  =       vti_input,
 384         .cb_handler     =       vti_rcv_cb,
 385         .err_handler    =       vti4_err,
 386         .priority       =       100,
 387 };
 388
 389 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = {
 390         .handler        =       vti_rcv,
 391         .input_handler  =       vti_input,
 392         .cb_handler     =       vti_rcv_cb,
 393         .err_handler    =       vti4_err,
 394         .priority       =       100,
 395 };
 396
 397 static int __net_init vti_init_net(struct net *net)
 398 {
 399         int err;
 400         struct ip_tunnel_net *itn;
 401
 402         err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0");
 403         if (err)
 404                 return err;
 405         itn = net_generic(net, vti_net_id);
 406         vti_fb_tunnel_init(itn->fb_tunnel_dev);
 407         return 0;
 408 }
 409
 410 static void __net_exit vti_exit_net(struct net *net)
 411 {
 412         struct ip_tunnel_net *itn = net_generic(net, vti_net_id);
 413         ip_tunnel_delete_net(itn, &vti_link_ops);
 414 }
 415
 416 static struct pernet_operations vti_net_ops = {
 417         .init = vti_init_net,
 418         .exit = vti_exit_net,
 419         .id   = &vti_net_id,
 420         .size = sizeof(struct ip_tunnel_net),
 421 };
 422
 423 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[])
 424 {
 425         return 0;
 426 }
 427
 428 static void vti_netlink_parms(struct nlattr *data[],
 429                               struct ip_tunnel_parm *parms)
 430 {
 431         memset(parms, 0, sizeof(*parms));
 432
 433         parms->iph.protocol = IPPROTO_IPIP;
 434
 435         if (!data)
 436                 return;
 437
 438         parms->i_flags = VTI_ISVTI;
 439
 440         if (data[IFLA_VTI_LINK])
 441                 parms->link = nla_get_u32(data[IFLA_VTI_LINK]);
 442
 443         if (data[IFLA_VTI_IKEY])
 444                 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]);
 445
 446         if (data[IFLA_VTI_OKEY])
 447                 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]);
 448
 449         if (data[IFLA_VTI_LOCAL])
 450                 parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]);
 451
 452         if (data[IFLA_VTI_REMOTE])
 453                 parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]);
 454
 455 }
 456
 457 static int vti_newlink(struct net *src_net, struct net_device *dev,
 458                        struct nlattr *tb[], struct nlattr *data[])
 459 {
 460         struct ip_tunnel_parm parms;
 461
 462         vti_netlink_parms(data, &parms);
 463         return ip_tunnel_newlink(dev, tb, &parms);
 464 }
 465
 466 static int vti_changelink(struct net_device *dev, struct nlattr *tb[],
 467                           struct nlattr *data[])
 468 {
 469         struct ip_tunnel_parm p;
 470
 471         vti_netlink_parms(data, &p);
 472         return ip_tunnel_changelink(dev, tb, &p);
 473 }
 474
 475 static size_t vti_get_size(const struct net_device *dev)
 476 {
 477         return
 478                 /* IFLA_VTI_LINK */
 479                 nla_total_size(4) +
 480                 /* IFLA_VTI_IKEY */
 481                 nla_total_size(4) +
 482                 /* IFLA_VTI_OKEY */
 483                 nla_total_size(4) +
 484                 /* IFLA_VTI_LOCAL */
 485                 nla_total_size(4) +
 486                 /* IFLA_VTI_REMOTE */
 487                 nla_total_size(4) +
 488                 0;
 489 }
 490
 491 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev)
 492 {
 493         struct ip_tunnel *t = netdev_priv(dev);
 494         struct ip_tunnel_parm *p = &t->parms;
 495
 496         nla_put_u32(skb, IFLA_VTI_LINK, p->link);
 497         nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key);
 498         nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key);
 499         nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr);
 500         nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr);
 501
 502         return 0;
 503 }
 504
 505 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = {
 506         [IFLA_VTI_LINK]         = { .type = NLA_U32 },
 507         [IFLA_VTI_IKEY]         = { .type = NLA_U32 },
 508         [IFLA_VTI_OKEY]         = { .type = NLA_U32 },
 509         [IFLA_VTI_LOCAL]        = { .len = FIELD_SIZEOF(struct iphdr, saddr) },
 510         [IFLA_VTI_REMOTE]       = { .len = FIELD_SIZEOF(struct iphdr, daddr) },
 511 };
 512
 513 static struct rtnl_link_ops vti_link_ops __read_mostly = {
 514         .kind           = "vti",
 515         .maxtype        = IFLA_VTI_MAX,
 516         .policy         = vti_policy,
 517         .priv_size      = sizeof(struct ip_tunnel),
 518         .setup          = vti_tunnel_setup,
 519         .validate       = vti_tunnel_validate,
 520         .newlink        = vti_newlink,
 521         .changelink     = vti_changelink,
 522         .get_size       = vti_get_size,
 523         .fill_info      = vti_fill_info,
 524 };
 525
 526 static int __init vti_init(void)
 527 {
 528         int err;
 529
 530         pr_info("IPv4 over IPSec tunneling driver\n");
 531
 532         err = register_pernet_device(&vti_net_ops);
 533         if (err < 0)
 534                 return err;
 535         err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP);
 536         if (err < 0) {
 537                 unregister_pernet_device(&vti_net_ops);
 538                 pr_info("vti init: can't register tunnel\n");
 539
 540                 return err;
 541         }
 542
 543         err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH);
 544         if (err < 0) {
 545                 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 546                 unregister_pernet_device(&vti_net_ops);
 547                 pr_info("vti init: can't register tunnel\n");
 548
 549                 return err;
 550         }
 551
 552         err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP);
 553         if (err < 0) {
 554                 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 555                 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 556                 unregister_pernet_device(&vti_net_ops);
 557                 pr_info("vti init: can't register tunnel\n");
 558
 559                 return err;
 560         }
 561
 562         err = rtnl_link_register(&vti_link_ops);
 563         if (err < 0)
 564                 goto rtnl_link_failed;
 565
 566         return err;
 567
 568 rtnl_link_failed:
 569         xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP);
 570         xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH);
 571         xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP);
 572         unregister_pernet_device(&vti_net_ops);
 573         return err;
 574 }
 575
 576 static void __exit vti_fini(void)
 577 {
 578         rtnl_link_unregister(&vti_link_ops);
 579         if (xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP))
 580                 pr_info("vti close: can't deregister tunnel\n");
 581         if (xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH))
 582                 pr_info("vti close: can't deregister tunnel\n");
 583         if (xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP))
 584                 pr_info("vti close: can't deregister tunnel\n");
 585
 586
 587         unregister_pernet_device(&vti_net_ops);
 588 }
 589
 590 module_init(vti_init);
 591 module_exit(vti_fini);
 592 MODULE_LICENSE("GPL");
 593 MODULE_ALIAS_RTNL_LINK("vti");
 594 MODULE_ALIAS_NETDEV("ip_vti0");