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 pkt_len = skb->len; 172 int err; 173 int mtu; 174 175 if (!dst) { 176 dev->stats.tx_carrier_errors++; 177 goto tx_error_icmp; 178 } 179 180 dst_hold(dst); 181 dst = xfrm_lookup(tunnel->net, dst, fl, NULL, 0); 182 if (IS_ERR(dst)) { 183 dev->stats.tx_carrier_errors++; 184 goto tx_error_icmp; 185 } 186 187 if (!vti_state_check(dst->xfrm, parms->iph.daddr, parms->iph.saddr)) { 188 dev->stats.tx_carrier_errors++; 189 dst_release(dst); 190 goto tx_error_icmp; 191 } 192 193 tdev = dst->dev; 194 195 if (tdev == dev) { 196 dst_release(dst); 197 dev->stats.collisions++; 198 goto tx_error; 199 } 200 201 mtu = dst_mtu(dst); 202 if (skb->len > mtu) { 203 skb_dst_update_pmtu(skb, mtu); 204 if (skb->protocol == htons(ETH_P_IP)) { 205 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 206 htonl(mtu)); 207 } else { 208 if (mtu < IPV6_MIN_MTU) 209 mtu = IPV6_MIN_MTU; 210 211 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 212 } 213 214 dst_release(dst); 215 goto tx_error; 216 } 217 218 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev))); 219 skb_dst_set(skb, dst); 220 skb->dev = skb_dst(skb)->dev; 221 222 err = dst_output(tunnel->net, skb->sk, skb); 223 if (net_xmit_eval(err) == 0) 224 err = pkt_len; 225 iptunnel_xmit_stats(dev, err); 226 return NETDEV_TX_OK; 227 228 tx_error_icmp: 229 dst_link_failure(skb); 230 tx_error: 231 dev->stats.tx_errors++; 232 kfree_skb(skb); 233 return NETDEV_TX_OK; 234 } 235 236 /* This function assumes it is being called from dev_queue_xmit() 237 * and that skb is filled properly by that function. 238 */ 239 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 240 { 241 struct ip_tunnel *tunnel = netdev_priv(dev); 242 struct flowi fl; 243 244 memset(&fl, 0, sizeof(fl)); 245 246 switch (skb->protocol) { 247 case htons(ETH_P_IP): 248 xfrm_decode_session(skb, &fl, AF_INET); 249 memset(IPCB(skb), 0, sizeof(*IPCB(skb))); 250 break; 251 case htons(ETH_P_IPV6): 252 xfrm_decode_session(skb, &fl, AF_INET6); 253 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); 254 break; 255 default: 256 dev->stats.tx_errors++; 257 dev_kfree_skb(skb); 258 return NETDEV_TX_OK; 259 } 260 261 /* override mark with tunnel output key */ 262 fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key); 263 264 return vti_xmit(skb, dev, &fl); 265 } 266 267 static int vti4_err(struct sk_buff *skb, u32 info) 268 { 269 __be32 spi; 270 __u32 mark; 271 struct xfrm_state *x; 272 struct ip_tunnel *tunnel; 273 struct ip_esp_hdr *esph; 274 struct ip_auth_hdr *ah ; 275 struct ip_comp_hdr *ipch; 276 struct net *net = dev_net(skb->dev); 277 const struct iphdr *iph = (const struct iphdr *)skb->data; 278 int protocol = iph->protocol; 279 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 280 281 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 282 iph->daddr, iph->saddr, 0); 283 if (!tunnel) 284 return -1; 285 286 mark = be32_to_cpu(tunnel->parms.o_key); 287 288 switch (protocol) { 289 case IPPROTO_ESP: 290 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 291 spi = esph->spi; 292 break; 293 case IPPROTO_AH: 294 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2)); 295 spi = ah->spi; 296 break; 297 case IPPROTO_COMP: 298 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); 299 spi = htonl(ntohs(ipch->cpi)); 300 break; 301 default: 302 return 0; 303 } 304 305 switch (icmp_hdr(skb)->type) { 306 case ICMP_DEST_UNREACH: 307 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 308 return 0; 309 case ICMP_REDIRECT: 310 break; 311 default: 312 return 0; 313 } 314 315 x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr, 316 spi, protocol, AF_INET); 317 if (!x) 318 return 0; 319 320 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 321 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0); 322 else 323 ipv4_redirect(skb, net, 0, 0, protocol, 0); 324 xfrm_state_put(x); 325 326 return 0; 327 } 328 329 static int 330 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 331 { 332 int err = 0; 333 struct ip_tunnel_parm p; 334 335 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 336 return -EFAULT; 337 338 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 339 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || 340 p.iph.ihl != 5) 341 return -EINVAL; 342 } 343 344 if (!(p.i_flags & GRE_KEY)) 345 p.i_key = 0; 346 if (!(p.o_flags & GRE_KEY)) 347 p.o_key = 0; 348 349 p.i_flags = VTI_ISVTI; 350 351 err = ip_tunnel_ioctl(dev, &p, cmd); 352 if (err) 353 return err; 354 355 if (cmd != SIOCDELTUNNEL) { 356 p.i_flags |= GRE_KEY; 357 p.o_flags |= GRE_KEY; 358 } 359 360 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 361 return -EFAULT; 362 return 0; 363 } 364 365 static const struct net_device_ops vti_netdev_ops = { 366 .ndo_init = vti_tunnel_init, 367 .ndo_uninit = ip_tunnel_uninit, 368 .ndo_start_xmit = vti_tunnel_xmit, 369 .ndo_do_ioctl = vti_tunnel_ioctl, 370 .ndo_change_mtu = ip_tunnel_change_mtu, 371 .ndo_get_stats64 = ip_tunnel_get_stats64, 372 .ndo_get_iflink = ip_tunnel_get_iflink, 373 }; 374 375 static void vti_tunnel_setup(struct net_device *dev) 376 { 377 dev->netdev_ops = &vti_netdev_ops; 378 dev->type = ARPHRD_TUNNEL; 379 ip_tunnel_setup(dev, vti_net_id); 380 } 381 382 static int vti_tunnel_init(struct net_device *dev) 383 { 384 struct ip_tunnel *tunnel = netdev_priv(dev); 385 struct iphdr *iph = &tunnel->parms.iph; 386 387 memcpy(dev->dev_addr, &iph->saddr, 4); 388 memcpy(dev->broadcast, &iph->daddr, 4); 389 390 dev->flags = IFF_NOARP; 391 dev->addr_len = 4; 392 dev->features |= NETIF_F_LLTX; 393 netif_keep_dst(dev); 394 395 return ip_tunnel_init(dev); 396 } 397 398 static void __net_init vti_fb_tunnel_init(struct net_device *dev) 399 { 400 struct ip_tunnel *tunnel = netdev_priv(dev); 401 struct iphdr *iph = &tunnel->parms.iph; 402 403 iph->version = 4; 404 iph->protocol = IPPROTO_IPIP; 405 iph->ihl = 5; 406 } 407 408 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = { 409 .handler = vti_rcv, 410 .input_handler = vti_input, 411 .cb_handler = vti_rcv_cb, 412 .err_handler = vti4_err, 413 .priority = 100, 414 }; 415 416 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = { 417 .handler = vti_rcv, 418 .input_handler = vti_input, 419 .cb_handler = vti_rcv_cb, 420 .err_handler = vti4_err, 421 .priority = 100, 422 }; 423 424 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = { 425 .handler = vti_rcv, 426 .input_handler = vti_input, 427 .cb_handler = vti_rcv_cb, 428 .err_handler = vti4_err, 429 .priority = 100, 430 }; 431 432 static int __net_init vti_init_net(struct net *net) 433 { 434 int err; 435 struct ip_tunnel_net *itn; 436 437 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0"); 438 if (err) 439 return err; 440 itn = net_generic(net, vti_net_id); 441 vti_fb_tunnel_init(itn->fb_tunnel_dev); 442 return 0; 443 } 444 445 static void __net_exit vti_exit_batch_net(struct list_head *list_net) 446 { 447 ip_tunnel_delete_nets(list_net, vti_net_id, &vti_link_ops); 448 } 449 450 static struct pernet_operations vti_net_ops = { 451 .init = vti_init_net, 452 .exit_batch = vti_exit_batch_net, 453 .id = &vti_net_id, 454 .size = sizeof(struct ip_tunnel_net), 455 }; 456 457 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[], 458 struct netlink_ext_ack *extack) 459 { 460 return 0; 461 } 462 463 static void vti_netlink_parms(struct nlattr *data[], 464 struct ip_tunnel_parm *parms, 465 __u32 *fwmark) 466 { 467 memset(parms, 0, sizeof(*parms)); 468 469 parms->iph.protocol = IPPROTO_IPIP; 470 471 if (!data) 472 return; 473 474 parms->i_flags = VTI_ISVTI; 475 476 if (data[IFLA_VTI_LINK]) 477 parms->link = nla_get_u32(data[IFLA_VTI_LINK]); 478 479 if (data[IFLA_VTI_IKEY]) 480 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]); 481 482 if (data[IFLA_VTI_OKEY]) 483 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]); 484 485 if (data[IFLA_VTI_LOCAL]) 486 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]); 487 488 if (data[IFLA_VTI_REMOTE]) 489 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]); 490 491 if (data[IFLA_VTI_FWMARK]) 492 *fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]); 493 } 494 495 static int vti_newlink(struct net *src_net, struct net_device *dev, 496 struct nlattr *tb[], struct nlattr *data[], 497 struct netlink_ext_ack *extack) 498 { 499 struct ip_tunnel_parm parms; 500 __u32 fwmark = 0; 501 502 vti_netlink_parms(data, &parms, &fwmark); 503 return ip_tunnel_newlink(dev, tb, &parms, fwmark); 504 } 505 506 static int vti_changelink(struct net_device *dev, struct nlattr *tb[], 507 struct nlattr *data[], 508 struct netlink_ext_ack *extack) 509 { 510 struct ip_tunnel *t = netdev_priv(dev); 511 __u32 fwmark = t->fwmark; 512 struct ip_tunnel_parm p; 513 514 vti_netlink_parms(data, &p, &fwmark); 515 return ip_tunnel_changelink(dev, tb, &p, fwmark); 516 } 517 518 static size_t vti_get_size(const struct net_device *dev) 519 { 520 return 521 /* IFLA_VTI_LINK */ 522 nla_total_size(4) + 523 /* IFLA_VTI_IKEY */ 524 nla_total_size(4) + 525 /* IFLA_VTI_OKEY */ 526 nla_total_size(4) + 527 /* IFLA_VTI_LOCAL */ 528 nla_total_size(4) + 529 /* IFLA_VTI_REMOTE */ 530 nla_total_size(4) + 531 /* IFLA_VTI_FWMARK */ 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 if (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 nla_put_u32(skb, IFLA_VTI_FWMARK, t->fwmark)) 547 return -EMSGSIZE; 548 549 return 0; 550 } 551 552 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = { 553 [IFLA_VTI_LINK] = { .type = NLA_U32 }, 554 [IFLA_VTI_IKEY] = { .type = NLA_U32 }, 555 [IFLA_VTI_OKEY] = { .type = NLA_U32 }, 556 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 557 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 558 [IFLA_VTI_FWMARK] = { .type = NLA_U32 }, 559 }; 560 561 static struct rtnl_link_ops vti_link_ops __read_mostly = { 562 .kind = "vti", 563 .maxtype = IFLA_VTI_MAX, 564 .policy = vti_policy, 565 .priv_size = sizeof(struct ip_tunnel), 566 .setup = vti_tunnel_setup, 567 .validate = vti_tunnel_validate, 568 .newlink = vti_newlink, 569 .changelink = vti_changelink, 570 .dellink = ip_tunnel_dellink, 571 .get_size = vti_get_size, 572 .fill_info = vti_fill_info, 573 .get_link_net = ip_tunnel_get_link_net, 574 }; 575 576 static int __init vti_init(void) 577 { 578 const char *msg; 579 int err; 580 581 pr_info("IPv4 over IPsec tunneling driver\n"); 582 583 msg = "tunnel device"; 584 err = register_pernet_device(&vti_net_ops); 585 if (err < 0) 586 goto pernet_dev_failed; 587 588 msg = "tunnel protocols"; 589 err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP); 590 if (err < 0) 591 goto xfrm_proto_esp_failed; 592 err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH); 593 if (err < 0) 594 goto xfrm_proto_ah_failed; 595 err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP); 596 if (err < 0) 597 goto xfrm_proto_comp_failed; 598 599 msg = "netlink interface"; 600 err = rtnl_link_register(&vti_link_ops); 601 if (err < 0) 602 goto rtnl_link_failed; 603 604 return err; 605 606 rtnl_link_failed: 607 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 608 xfrm_proto_comp_failed: 609 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 610 xfrm_proto_ah_failed: 611 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 612 xfrm_proto_esp_failed: 613 unregister_pernet_device(&vti_net_ops); 614 pernet_dev_failed: 615 pr_err("vti init: failed to register %s\n", msg); 616 return err; 617 } 618 619 static void __exit vti_fini(void) 620 { 621 rtnl_link_unregister(&vti_link_ops); 622 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 623 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 624 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 625 unregister_pernet_device(&vti_net_ops); 626 } 627 628 module_init(vti_init); 629 module_exit(vti_fini); 630 MODULE_LICENSE("GPL"); 631 MODULE_ALIAS_RTNL_LINK("vti"); 632 MODULE_ALIAS_NETDEV("ip_vti0"); 633