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