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/init.h> 34 #include <linux/netfilter_ipv4.h> 35 #include <linux/if_ether.h> 36 #include <linux/icmpv6.h> 37 38 #include <net/sock.h> 39 #include <net/ip.h> 40 #include <net/icmp.h> 41 #include <net/ip_tunnels.h> 42 #include <net/inet_ecn.h> 43 #include <net/xfrm.h> 44 #include <net/net_namespace.h> 45 #include <net/netns/generic.h> 46 47 static struct rtnl_link_ops vti_link_ops __read_mostly; 48 49 static unsigned int vti_net_id __read_mostly; 50 static int vti_tunnel_init(struct net_device *dev); 51 52 static int vti_input(struct sk_buff *skb, int nexthdr, __be32 spi, 53 int encap_type) 54 { 55 struct ip_tunnel *tunnel; 56 const struct iphdr *iph = ip_hdr(skb); 57 struct net *net = dev_net(skb->dev); 58 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 59 60 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 61 iph->saddr, iph->daddr, 0); 62 if (tunnel) { 63 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 64 goto drop; 65 66 XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = tunnel; 67 68 return xfrm_input(skb, nexthdr, spi, encap_type); 69 } 70 71 return -EINVAL; 72 drop: 73 kfree_skb(skb); 74 return 0; 75 } 76 77 static int vti_rcv(struct sk_buff *skb) 78 { 79 XFRM_SPI_SKB_CB(skb)->family = AF_INET; 80 XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr); 81 82 return vti_input(skb, ip_hdr(skb)->protocol, 0, 0); 83 } 84 85 static int vti_rcv_cb(struct sk_buff *skb, int err) 86 { 87 unsigned short family; 88 struct net_device *dev; 89 struct pcpu_sw_netstats *tstats; 90 struct xfrm_state *x; 91 struct xfrm_mode *inner_mode; 92 struct ip_tunnel *tunnel = XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4; 93 u32 orig_mark = skb->mark; 94 int ret; 95 96 if (!tunnel) 97 return 1; 98 99 dev = tunnel->dev; 100 101 if (err) { 102 dev->stats.rx_errors++; 103 dev->stats.rx_dropped++; 104 105 return 0; 106 } 107 108 x = xfrm_input_state(skb); 109 110 inner_mode = x->inner_mode; 111 112 if (x->sel.family == AF_UNSPEC) { 113 inner_mode = xfrm_ip2inner_mode(x, XFRM_MODE_SKB_CB(skb)->protocol); 114 if (inner_mode == NULL) { 115 XFRM_INC_STATS(dev_net(skb->dev), 116 LINUX_MIB_XFRMINSTATEMODEERROR); 117 return -EINVAL; 118 } 119 } 120 121 family = inner_mode->afinfo->family; 122 123 skb->mark = be32_to_cpu(tunnel->parms.i_key); 124 ret = xfrm_policy_check(NULL, XFRM_POLICY_IN, skb, family); 125 skb->mark = orig_mark; 126 127 if (!ret) 128 return -EPERM; 129 130 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(skb->dev))); 131 skb->dev = dev; 132 133 tstats = this_cpu_ptr(dev->tstats); 134 135 u64_stats_update_begin(&tstats->syncp); 136 tstats->rx_packets++; 137 tstats->rx_bytes += skb->len; 138 u64_stats_update_end(&tstats->syncp); 139 140 return 0; 141 } 142 143 static bool vti_state_check(const struct xfrm_state *x, __be32 dst, __be32 src) 144 { 145 xfrm_address_t *daddr = (xfrm_address_t *)&dst; 146 xfrm_address_t *saddr = (xfrm_address_t *)&src; 147 148 /* if there is no transform then this tunnel is not functional. 149 * Or if the xfrm is not mode tunnel. 150 */ 151 if (!x || x->props.mode != XFRM_MODE_TUNNEL || 152 x->props.family != AF_INET) 153 return false; 154 155 if (!dst) 156 return xfrm_addr_equal(saddr, &x->props.saddr, AF_INET); 157 158 if (!xfrm_state_addr_check(x, daddr, saddr, AF_INET)) 159 return false; 160 161 return true; 162 } 163 164 static netdev_tx_t vti_xmit(struct sk_buff *skb, struct net_device *dev, 165 struct flowi *fl) 166 { 167 struct ip_tunnel *tunnel = netdev_priv(dev); 168 struct ip_tunnel_parm *parms = &tunnel->parms; 169 struct dst_entry *dst = skb_dst(skb); 170 struct net_device *tdev; /* Device to other host */ 171 int err; 172 int mtu; 173 174 if (!dst) { 175 dev->stats.tx_carrier_errors++; 176 goto tx_error_icmp; 177 } 178 179 dst_hold(dst); 180 dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0); 181 if (IS_ERR(dst)) { 182 dev->stats.tx_carrier_errors++; 183 goto tx_error_icmp; 184 } 185 186 if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) { 187 dev->stats.tx_carrier_errors++; 188 dst_release(dst); 189 goto tx_error_icmp; 190 } 191 192 tdev = dst->dev; 193 194 if (tdev == dev) { 195 dst_release(dst); 196 dev->stats.collisions++; 197 goto tx_error; 198 } 199 200 if (tunnel->err_count > 0) { 201 if (time_before(jiffies, 202 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) { 203 tunnel->err_count--; 204 dst_link_failure(skb); 205 } else 206 tunnel->err_count = 0; 207 } 208 209 mtu = dst_mtu(dst); 210 if (skb->len > mtu) { 211 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); 212 if (skb->protocol == htons(ETH_P_IP)) { 213 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 214 htonl(mtu)); 215 } else { 216 if (mtu < IPV6_MIN_MTU) 217 mtu = IPV6_MIN_MTU; 218 219 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 220 } 221 222 dst_release(dst); 223 goto tx_error; 224 } 225 226 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev))); 227 skb_dst_set(skb, dst); 228 skb->dev = skb_dst(skb)->dev; 229 230 err = dst_output(tunnel->net, skb->sk, skb); 231 if (net_xmit_eval(err) == 0) 232 err = skb->len; 233 iptunnel_xmit_stats(dev, err); 234 return NETDEV_TX_OK; 235 236 tx_error_icmp: 237 dst_link_failure(skb); 238 tx_error: 239 dev->stats.tx_errors++; 240 kfree_skb(skb); 241 return NETDEV_TX_OK; 242 } 243 244 /* This function assumes it is being called from dev_queue_xmit() 245 * and that skb is filled properly by that function. 246 */ 247 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 248 { 249 struct ip_tunnel *tunnel = netdev_priv(dev); 250 struct flowi fl; 251 252 memset(&fl, 0, sizeof(fl)); 253 254 switch (skb->protocol) { 255 case htons(ETH_P_IP): 256 xfrm_decode_session(skb, &fl, AF_INET); 257 memset(IPCB(skb), 0, sizeof(*IPCB(skb))); 258 break; 259 case htons(ETH_P_IPV6): 260 xfrm_decode_session(skb, &fl, AF_INET6); 261 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); 262 break; 263 default: 264 dev->stats.tx_errors++; 265 dev_kfree_skb(skb); 266 return NETDEV_TX_OK; 267 } 268 269 /* override mark with tunnel output key */ 270 fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key); 271 272 return vti_xmit(skb, dev, &fl); 273 } 274 275 static int vti4_err(struct sk_buff *skb, u32 info) 276 { 277 __be32 spi; 278 __u32 mark; 279 struct xfrm_state *x; 280 struct ip_tunnel *tunnel; 281 struct ip_esp_hdr *esph; 282 struct ip_auth_hdr *ah ; 283 struct ip_comp_hdr *ipch; 284 struct net *net = dev_net(skb->dev); 285 const struct iphdr *iph = (const struct iphdr *)skb->data; 286 int protocol = iph->protocol; 287 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 288 289 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 290 iph->daddr, iph->saddr, 0); 291 if (!tunnel) 292 return -1; 293 294 mark = be32_to_cpu(tunnel->parms.o_key); 295 296 switch (protocol) { 297 case IPPROTO_ESP: 298 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 299 spi = esph->spi; 300 break; 301 case IPPROTO_AH: 302 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2)); 303 spi = ah->spi; 304 break; 305 case IPPROTO_COMP: 306 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); 307 spi = htonl(ntohs(ipch->cpi)); 308 break; 309 default: 310 return 0; 311 } 312 313 switch (icmp_hdr(skb)->type) { 314 case ICMP_DEST_UNREACH: 315 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 316 return 0; 317 case ICMP_REDIRECT: 318 break; 319 default: 320 return 0; 321 } 322 323 x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr, 324 spi, protocol, AF_INET); 325 if (!x) 326 return 0; 327 328 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 329 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0); 330 else 331 ipv4_redirect(skb, net, 0, 0, protocol, 0); 332 xfrm_state_put(x); 333 334 return 0; 335 } 336 337 static int 338 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 339 { 340 int err = 0; 341 struct ip_tunnel_parm p; 342 343 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 344 return -EFAULT; 345 346 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 347 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || 348 p.iph.ihl != 5) 349 return -EINVAL; 350 } 351 352 if (!(p.i_flags & GRE_KEY)) 353 p.i_key = 0; 354 if (!(p.o_flags & GRE_KEY)) 355 p.o_key = 0; 356 357 p.i_flags = VTI_ISVTI; 358 359 err = ip_tunnel_ioctl(dev, &p, cmd); 360 if (err) 361 return err; 362 363 if (cmd != SIOCDELTUNNEL) { 364 p.i_flags |= GRE_KEY; 365 p.o_flags |= GRE_KEY; 366 } 367 368 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 369 return -EFAULT; 370 return 0; 371 } 372 373 static const struct net_device_ops vti_netdev_ops = { 374 .ndo_init = vti_tunnel_init, 375 .ndo_uninit = ip_tunnel_uninit, 376 .ndo_start_xmit = vti_tunnel_xmit, 377 .ndo_do_ioctl = vti_tunnel_ioctl, 378 .ndo_change_mtu = ip_tunnel_change_mtu, 379 .ndo_get_stats64 = ip_tunnel_get_stats64, 380 .ndo_get_iflink = ip_tunnel_get_iflink, 381 }; 382 383 static void vti_tunnel_setup(struct net_device *dev) 384 { 385 dev->netdev_ops = &vti_netdev_ops; 386 dev->type = ARPHRD_TUNNEL; 387 ip_tunnel_setup(dev, vti_net_id); 388 } 389 390 static int vti_tunnel_init(struct net_device *dev) 391 { 392 struct ip_tunnel *tunnel = netdev_priv(dev); 393 struct iphdr *iph = &tunnel->parms.iph; 394 395 memcpy(dev->dev_addr, &iph->saddr, 4); 396 memcpy(dev->broadcast, &iph->daddr, 4); 397 398 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 399 dev->mtu = ETH_DATA_LEN; 400 dev->flags = IFF_NOARP; 401 dev->addr_len = 4; 402 dev->features |= NETIF_F_LLTX; 403 netif_keep_dst(dev); 404 405 return ip_tunnel_init(dev); 406 } 407 408 static void __net_init vti_fb_tunnel_init(struct net_device *dev) 409 { 410 struct ip_tunnel *tunnel = netdev_priv(dev); 411 struct iphdr *iph = &tunnel->parms.iph; 412 413 iph->version = 4; 414 iph->protocol = IPPROTO_IPIP; 415 iph->ihl = 5; 416 } 417 418 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = { 419 .handler = vti_rcv, 420 .input_handler = vti_input, 421 .cb_handler = vti_rcv_cb, 422 .err_handler = vti4_err, 423 .priority = 100, 424 }; 425 426 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = { 427 .handler = vti_rcv, 428 .input_handler = vti_input, 429 .cb_handler = vti_rcv_cb, 430 .err_handler = vti4_err, 431 .priority = 100, 432 }; 433 434 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = { 435 .handler = vti_rcv, 436 .input_handler = vti_input, 437 .cb_handler = vti_rcv_cb, 438 .err_handler = vti4_err, 439 .priority = 100, 440 }; 441 442 static int __net_init vti_init_net(struct net *net) 443 { 444 int err; 445 struct ip_tunnel_net *itn; 446 447 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0"); 448 if (err) 449 return err; 450 itn = net_generic(net, vti_net_id); 451 vti_fb_tunnel_init(itn->fb_tunnel_dev); 452 return 0; 453 } 454 455 static void __net_exit vti_exit_net(struct net *net) 456 { 457 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 458 ip_tunnel_delete_net(itn, &vti_link_ops); 459 } 460 461 static struct pernet_operations vti_net_ops = { 462 .init = vti_init_net, 463 .exit = vti_exit_net, 464 .id = &vti_net_id, 465 .size = sizeof(struct ip_tunnel_net), 466 }; 467 468 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) 469 { 470 return 0; 471 } 472 473 static void vti_netlink_parms(struct nlattr *data[], 474 struct ip_tunnel_parm *parms) 475 { 476 memset(parms, 0, sizeof(*parms)); 477 478 parms->iph.protocol = IPPROTO_IPIP; 479 480 if (!data) 481 return; 482 483 parms->i_flags = VTI_ISVTI; 484 485 if (data[IFLA_VTI_LINK]) 486 parms->link = nla_get_u32(data[IFLA_VTI_LINK]); 487 488 if (data[IFLA_VTI_IKEY]) 489 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]); 490 491 if (data[IFLA_VTI_OKEY]) 492 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]); 493 494 if (data[IFLA_VTI_LOCAL]) 495 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]); 496 497 if (data[IFLA_VTI_REMOTE]) 498 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]); 499 500 } 501 502 static int vti_newlink(struct net *src_net, struct net_device *dev, 503 struct nlattr *tb[], struct nlattr *data[]) 504 { 505 struct ip_tunnel_parm parms; 506 507 vti_netlink_parms(data, &parms); 508 return ip_tunnel_newlink(dev, tb, &parms); 509 } 510 511 static int vti_changelink(struct net_device *dev, struct nlattr *tb[], 512 struct nlattr *data[]) 513 { 514 struct ip_tunnel_parm p; 515 516 vti_netlink_parms(data, &p); 517 return ip_tunnel_changelink(dev, tb, &p); 518 } 519 520 static size_t vti_get_size(const struct net_device *dev) 521 { 522 return 523 /* IFLA_VTI_LINK */ 524 nla_total_size(4) + 525 /* IFLA_VTI_IKEY */ 526 nla_total_size(4) + 527 /* IFLA_VTI_OKEY */ 528 nla_total_size(4) + 529 /* IFLA_VTI_LOCAL */ 530 nla_total_size(4) + 531 /* IFLA_VTI_REMOTE */ 532 nla_total_size(4) + 533 0; 534 } 535 536 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev) 537 { 538 struct ip_tunnel *t = netdev_priv(dev); 539 struct ip_tunnel_parm *p = &t->parms; 540 541 nla_put_u32(skb, IFLA_VTI_LINK, p->link); 542 nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key); 543 nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key); 544 nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr); 545 nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr); 546 547 return 0; 548 } 549 550 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = { 551 [IFLA_VTI_LINK] = { .type = NLA_U32 }, 552 [IFLA_VTI_IKEY] = { .type = NLA_U32 }, 553 [IFLA_VTI_OKEY] = { .type = NLA_U32 }, 554 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 555 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 556 }; 557 558 static struct rtnl_link_ops vti_link_ops __read_mostly = { 559 .kind = "vti", 560 .maxtype = IFLA_VTI_MAX, 561 .policy = vti_policy, 562 .priv_size = sizeof(struct ip_tunnel), 563 .setup = vti_tunnel_setup, 564 .validate = vti_tunnel_validate, 565 .newlink = vti_newlink, 566 .changelink = vti_changelink, 567 .dellink = ip_tunnel_dellink, 568 .get_size = vti_get_size, 569 .fill_info = vti_fill_info, 570 .get_link_net = ip_tunnel_get_link_net, 571 }; 572 573 static bool is_vti_tunnel(const struct net_device *dev) 574 { 575 return dev->netdev_ops == &vti_netdev_ops; 576 } 577 578 static int vti_device_event(struct notifier_block *unused, 579 unsigned long event, void *ptr) 580 { 581 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 582 struct ip_tunnel *tunnel = netdev_priv(dev); 583 584 if (!is_vti_tunnel(dev)) 585 return NOTIFY_DONE; 586 587 switch (event) { 588 case NETDEV_DOWN: 589 if (!net_eq(tunnel->net, dev_net(dev))) 590 xfrm_garbage_collect(tunnel->net); 591 break; 592 } 593 return NOTIFY_DONE; 594 } 595 596 static struct notifier_block vti_notifier_block __read_mostly = { 597 .notifier_call = vti_device_event, 598 }; 599 600 static int __init vti_init(void) 601 { 602 const char *msg; 603 int err; 604 605 pr_info("IPv4 over IPsec tunneling driver\n"); 606 607 register_netdevice_notifier(&vti_notifier_block); 608 609 msg = "tunnel device"; 610 err = register_pernet_device(&vti_net_ops); 611 if (err < 0) 612 goto pernet_dev_failed; 613 614 msg = "tunnel protocols"; 615 err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP); 616 if (err < 0) 617 goto xfrm_proto_esp_failed; 618 err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH); 619 if (err < 0) 620 goto xfrm_proto_ah_failed; 621 err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP); 622 if (err < 0) 623 goto xfrm_proto_comp_failed; 624 625 msg = "netlink interface"; 626 err = rtnl_link_register(&vti_link_ops); 627 if (err < 0) 628 goto rtnl_link_failed; 629 630 return err; 631 632 rtnl_link_failed: 633 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 634 xfrm_proto_comp_failed: 635 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 636 xfrm_proto_ah_failed: 637 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 638 xfrm_proto_esp_failed: 639 unregister_pernet_device(&vti_net_ops); 640 pernet_dev_failed: 641 unregister_netdevice_notifier(&vti_notifier_block); 642 pr_err("vti init: failed to register %s\n", msg); 643 return err; 644 } 645 646 static void __exit vti_fini(void) 647 { 648 rtnl_link_unregister(&vti_link_ops); 649 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 650 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 651 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 652 unregister_pernet_device(&vti_net_ops); 653 unregister_netdevice_notifier(&vti_notifier_block); 654 } 655 656 module_init(vti_init); 657 module_exit(vti_fini); 658 MODULE_LICENSE("GPL"); 659 MODULE_ALIAS_RTNL_LINK("vti"); 660 MODULE_ALIAS_NETDEV("ip_vti0"); 661