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"); 595