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) { 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 __u32 mark; 243 struct xfrm_state *x; 244 struct ip_tunnel *tunnel; 245 struct ip_esp_hdr *esph; 246 struct ip_auth_hdr *ah ; 247 struct ip_comp_hdr *ipch; 248 struct net *net = dev_net(skb->dev); 249 const struct iphdr *iph = (const struct iphdr *)skb->data; 250 int protocol = iph->protocol; 251 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 252 253 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 254 iph->daddr, iph->saddr, 0); 255 if (!tunnel) 256 return -1; 257 258 mark = be32_to_cpu(tunnel->parms.o_key); 259 260 switch (protocol) { 261 case IPPROTO_ESP: 262 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 263 spi = esph->spi; 264 break; 265 case IPPROTO_AH: 266 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2)); 267 spi = ah->spi; 268 break; 269 case IPPROTO_COMP: 270 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); 271 spi = htonl(ntohs(ipch->cpi)); 272 break; 273 default: 274 return 0; 275 } 276 277 switch (icmp_hdr(skb)->type) { 278 case ICMP_DEST_UNREACH: 279 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 280 return 0; 281 case ICMP_REDIRECT: 282 break; 283 default: 284 return 0; 285 } 286 287 x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr, 288 spi, protocol, AF_INET); 289 if (!x) 290 return 0; 291 292 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 293 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0); 294 else 295 ipv4_redirect(skb, net, 0, 0, protocol, 0); 296 xfrm_state_put(x); 297 298 return 0; 299 } 300 301 static int 302 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 303 { 304 int err = 0; 305 struct ip_tunnel_parm p; 306 307 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 308 return -EFAULT; 309 310 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 311 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || 312 p.iph.ihl != 5) 313 return -EINVAL; 314 } 315 316 if (!(p.i_flags & GRE_KEY)) 317 p.i_key = 0; 318 if (!(p.o_flags & GRE_KEY)) 319 p.o_key = 0; 320 321 p.i_flags = VTI_ISVTI; 322 323 err = ip_tunnel_ioctl(dev, &p, cmd); 324 if (err) 325 return err; 326 327 if (cmd != SIOCDELTUNNEL) { 328 p.i_flags |= GRE_KEY; 329 p.o_flags |= GRE_KEY; 330 } 331 332 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 333 return -EFAULT; 334 return 0; 335 } 336 337 static const struct net_device_ops vti_netdev_ops = { 338 .ndo_init = vti_tunnel_init, 339 .ndo_uninit = ip_tunnel_uninit, 340 .ndo_start_xmit = vti_tunnel_xmit, 341 .ndo_do_ioctl = vti_tunnel_ioctl, 342 .ndo_change_mtu = ip_tunnel_change_mtu, 343 .ndo_get_stats64 = ip_tunnel_get_stats64, 344 .ndo_get_iflink = ip_tunnel_get_iflink, 345 }; 346 347 static void vti_tunnel_setup(struct net_device *dev) 348 { 349 dev->netdev_ops = &vti_netdev_ops; 350 dev->type = ARPHRD_TUNNEL; 351 ip_tunnel_setup(dev, vti_net_id); 352 } 353 354 static int vti_tunnel_init(struct net_device *dev) 355 { 356 struct ip_tunnel *tunnel = netdev_priv(dev); 357 struct iphdr *iph = &tunnel->parms.iph; 358 359 memcpy(dev->dev_addr, &iph->saddr, 4); 360 memcpy(dev->broadcast, &iph->daddr, 4); 361 362 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 363 dev->mtu = ETH_DATA_LEN; 364 dev->flags = IFF_NOARP; 365 dev->addr_len = 4; 366 dev->features |= NETIF_F_LLTX; 367 netif_keep_dst(dev); 368 369 return ip_tunnel_init(dev); 370 } 371 372 static void __net_init vti_fb_tunnel_init(struct net_device *dev) 373 { 374 struct ip_tunnel *tunnel = netdev_priv(dev); 375 struct iphdr *iph = &tunnel->parms.iph; 376 377 iph->version = 4; 378 iph->protocol = IPPROTO_IPIP; 379 iph->ihl = 5; 380 } 381 382 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = { 383 .handler = vti_rcv, 384 .input_handler = vti_input, 385 .cb_handler = vti_rcv_cb, 386 .err_handler = vti4_err, 387 .priority = 100, 388 }; 389 390 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = { 391 .handler = vti_rcv, 392 .input_handler = vti_input, 393 .cb_handler = vti_rcv_cb, 394 .err_handler = vti4_err, 395 .priority = 100, 396 }; 397 398 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = { 399 .handler = vti_rcv, 400 .input_handler = vti_input, 401 .cb_handler = vti_rcv_cb, 402 .err_handler = vti4_err, 403 .priority = 100, 404 }; 405 406 static int __net_init vti_init_net(struct net *net) 407 { 408 int err; 409 struct ip_tunnel_net *itn; 410 411 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0"); 412 if (err) 413 return err; 414 itn = net_generic(net, vti_net_id); 415 vti_fb_tunnel_init(itn->fb_tunnel_dev); 416 return 0; 417 } 418 419 static void __net_exit vti_exit_net(struct net *net) 420 { 421 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 422 ip_tunnel_delete_net(itn, &vti_link_ops); 423 } 424 425 static struct pernet_operations vti_net_ops = { 426 .init = vti_init_net, 427 .exit = vti_exit_net, 428 .id = &vti_net_id, 429 .size = sizeof(struct ip_tunnel_net), 430 }; 431 432 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) 433 { 434 return 0; 435 } 436 437 static void vti_netlink_parms(struct nlattr *data[], 438 struct ip_tunnel_parm *parms) 439 { 440 memset(parms, 0, sizeof(*parms)); 441 442 parms->iph.protocol = IPPROTO_IPIP; 443 444 if (!data) 445 return; 446 447 parms->i_flags = VTI_ISVTI; 448 449 if (data[IFLA_VTI_LINK]) 450 parms->link = nla_get_u32(data[IFLA_VTI_LINK]); 451 452 if (data[IFLA_VTI_IKEY]) 453 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]); 454 455 if (data[IFLA_VTI_OKEY]) 456 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]); 457 458 if (data[IFLA_VTI_LOCAL]) 459 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]); 460 461 if (data[IFLA_VTI_REMOTE]) 462 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]); 463 464 } 465 466 static int vti_newlink(struct net *src_net, struct net_device *dev, 467 struct nlattr *tb[], struct nlattr *data[]) 468 { 469 struct ip_tunnel_parm parms; 470 471 vti_netlink_parms(data, &parms); 472 return ip_tunnel_newlink(dev, tb, &parms); 473 } 474 475 static int vti_changelink(struct net_device *dev, struct nlattr *tb[], 476 struct nlattr *data[]) 477 { 478 struct ip_tunnel_parm p; 479 480 vti_netlink_parms(data, &p); 481 return ip_tunnel_changelink(dev, tb, &p); 482 } 483 484 static size_t vti_get_size(const struct net_device *dev) 485 { 486 return 487 /* IFLA_VTI_LINK */ 488 nla_total_size(4) + 489 /* IFLA_VTI_IKEY */ 490 nla_total_size(4) + 491 /* IFLA_VTI_OKEY */ 492 nla_total_size(4) + 493 /* IFLA_VTI_LOCAL */ 494 nla_total_size(4) + 495 /* IFLA_VTI_REMOTE */ 496 nla_total_size(4) + 497 0; 498 } 499 500 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev) 501 { 502 struct ip_tunnel *t = netdev_priv(dev); 503 struct ip_tunnel_parm *p = &t->parms; 504 505 nla_put_u32(skb, IFLA_VTI_LINK, p->link); 506 nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key); 507 nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key); 508 nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr); 509 nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr); 510 511 return 0; 512 } 513 514 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = { 515 [IFLA_VTI_LINK] = { .type = NLA_U32 }, 516 [IFLA_VTI_IKEY] = { .type = NLA_U32 }, 517 [IFLA_VTI_OKEY] = { .type = NLA_U32 }, 518 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 519 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 520 }; 521 522 static struct rtnl_link_ops vti_link_ops __read_mostly = { 523 .kind = "vti", 524 .maxtype = IFLA_VTI_MAX, 525 .policy = vti_policy, 526 .priv_size = sizeof(struct ip_tunnel), 527 .setup = vti_tunnel_setup, 528 .validate = vti_tunnel_validate, 529 .newlink = vti_newlink, 530 .changelink = vti_changelink, 531 .dellink = ip_tunnel_dellink, 532 .get_size = vti_get_size, 533 .fill_info = vti_fill_info, 534 .get_link_net = ip_tunnel_get_link_net, 535 }; 536 537 static int __init vti_init(void) 538 { 539 const char *msg; 540 int err; 541 542 pr_info("IPv4 over IPsec tunneling driver\n"); 543 544 msg = "tunnel device"; 545 err = register_pernet_device(&vti_net_ops); 546 if (err < 0) 547 goto pernet_dev_failed; 548 549 msg = "tunnel protocols"; 550 err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP); 551 if (err < 0) 552 goto xfrm_proto_esp_failed; 553 err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH); 554 if (err < 0) 555 goto xfrm_proto_ah_failed; 556 err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP); 557 if (err < 0) 558 goto xfrm_proto_comp_failed; 559 560 msg = "netlink interface"; 561 err = rtnl_link_register(&vti_link_ops); 562 if (err < 0) 563 goto rtnl_link_failed; 564 565 return err; 566 567 rtnl_link_failed: 568 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 569 xfrm_proto_comp_failed: 570 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 571 xfrm_proto_ah_failed: 572 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 573 xfrm_proto_esp_failed: 574 unregister_pernet_device(&vti_net_ops); 575 pernet_dev_failed: 576 pr_err("vti init: failed to register %s\n", msg); 577 return err; 578 } 579 580 static void __exit vti_fini(void) 581 { 582 rtnl_link_unregister(&vti_link_ops); 583 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 584 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 585 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 586 unregister_pernet_device(&vti_net_ops); 587 } 588 589 module_init(vti_init); 590 module_exit(vti_fini); 591 MODULE_LICENSE("GPL"); 592 MODULE_ALIAS_RTNL_LINK("vti"); 593 MODULE_ALIAS_NETDEV("ip_vti0"); 594