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