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 if (tunnel->err_count > 0) { 202 if (time_before(jiffies, 203 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) { 204 tunnel->err_count--; 205 dst_link_failure(skb); 206 } else 207 tunnel->err_count = 0; 208 } 209 210 mtu = dst_mtu(dst); 211 if (skb->len > mtu) { 212 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu); 213 if (skb->protocol == htons(ETH_P_IP)) { 214 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, 215 htonl(mtu)); 216 } else { 217 if (mtu < IPV6_MIN_MTU) 218 mtu = IPV6_MIN_MTU; 219 220 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 221 } 222 223 dst_release(dst); 224 goto tx_error; 225 } 226 227 skb_scrub_packet(skb, !net_eq(tunnel->net, dev_net(dev))); 228 skb_dst_set(skb, dst); 229 skb->dev = skb_dst(skb)->dev; 230 231 err = dst_output(tunnel->net, skb->sk, skb); 232 if (net_xmit_eval(err) == 0) 233 err = pkt_len; 234 iptunnel_xmit_stats(dev, err); 235 return NETDEV_TX_OK; 236 237 tx_error_icmp: 238 dst_link_failure(skb); 239 tx_error: 240 dev->stats.tx_errors++; 241 kfree_skb(skb); 242 return NETDEV_TX_OK; 243 } 244 245 /* This function assumes it is being called from dev_queue_xmit() 246 * and that skb is filled properly by that function. 247 */ 248 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 249 { 250 struct ip_tunnel *tunnel = netdev_priv(dev); 251 struct flowi fl; 252 253 memset(&fl, 0, sizeof(fl)); 254 255 switch (skb->protocol) { 256 case htons(ETH_P_IP): 257 xfrm_decode_session(skb, &fl, AF_INET); 258 memset(IPCB(skb), 0, sizeof(*IPCB(skb))); 259 break; 260 case htons(ETH_P_IPV6): 261 xfrm_decode_session(skb, &fl, AF_INET6); 262 memset(IP6CB(skb), 0, sizeof(*IP6CB(skb))); 263 break; 264 default: 265 dev->stats.tx_errors++; 266 dev_kfree_skb(skb); 267 return NETDEV_TX_OK; 268 } 269 270 /* override mark with tunnel output key */ 271 fl.flowi_mark = be32_to_cpu(tunnel->parms.o_key); 272 273 return vti_xmit(skb, dev, &fl); 274 } 275 276 static int vti4_err(struct sk_buff *skb, u32 info) 277 { 278 __be32 spi; 279 __u32 mark; 280 struct xfrm_state *x; 281 struct ip_tunnel *tunnel; 282 struct ip_esp_hdr *esph; 283 struct ip_auth_hdr *ah ; 284 struct ip_comp_hdr *ipch; 285 struct net *net = dev_net(skb->dev); 286 const struct iphdr *iph = (const struct iphdr *)skb->data; 287 int protocol = iph->protocol; 288 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 289 290 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 291 iph->daddr, iph->saddr, 0); 292 if (!tunnel) 293 return -1; 294 295 mark = be32_to_cpu(tunnel->parms.o_key); 296 297 switch (protocol) { 298 case IPPROTO_ESP: 299 esph = (struct ip_esp_hdr *)(skb->data+(iph->ihl<<2)); 300 spi = esph->spi; 301 break; 302 case IPPROTO_AH: 303 ah = (struct ip_auth_hdr *)(skb->data+(iph->ihl<<2)); 304 spi = ah->spi; 305 break; 306 case IPPROTO_COMP: 307 ipch = (struct ip_comp_hdr *)(skb->data+(iph->ihl<<2)); 308 spi = htonl(ntohs(ipch->cpi)); 309 break; 310 default: 311 return 0; 312 } 313 314 switch (icmp_hdr(skb)->type) { 315 case ICMP_DEST_UNREACH: 316 if (icmp_hdr(skb)->code != ICMP_FRAG_NEEDED) 317 return 0; 318 case ICMP_REDIRECT: 319 break; 320 default: 321 return 0; 322 } 323 324 x = xfrm_state_lookup(net, mark, (const xfrm_address_t *)&iph->daddr, 325 spi, protocol, AF_INET); 326 if (!x) 327 return 0; 328 329 if (icmp_hdr(skb)->type == ICMP_DEST_UNREACH) 330 ipv4_update_pmtu(skb, net, info, 0, 0, protocol, 0); 331 else 332 ipv4_redirect(skb, net, 0, 0, protocol, 0); 333 xfrm_state_put(x); 334 335 return 0; 336 } 337 338 static int 339 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 340 { 341 int err = 0; 342 struct ip_tunnel_parm p; 343 344 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 345 return -EFAULT; 346 347 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 348 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || 349 p.iph.ihl != 5) 350 return -EINVAL; 351 } 352 353 if (!(p.i_flags & GRE_KEY)) 354 p.i_key = 0; 355 if (!(p.o_flags & GRE_KEY)) 356 p.o_key = 0; 357 358 p.i_flags = VTI_ISVTI; 359 360 err = ip_tunnel_ioctl(dev, &p, cmd); 361 if (err) 362 return err; 363 364 if (cmd != SIOCDELTUNNEL) { 365 p.i_flags |= GRE_KEY; 366 p.o_flags |= GRE_KEY; 367 } 368 369 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 370 return -EFAULT; 371 return 0; 372 } 373 374 static const struct net_device_ops vti_netdev_ops = { 375 .ndo_init = vti_tunnel_init, 376 .ndo_uninit = ip_tunnel_uninit, 377 .ndo_start_xmit = vti_tunnel_xmit, 378 .ndo_do_ioctl = vti_tunnel_ioctl, 379 .ndo_change_mtu = ip_tunnel_change_mtu, 380 .ndo_get_stats64 = ip_tunnel_get_stats64, 381 .ndo_get_iflink = ip_tunnel_get_iflink, 382 }; 383 384 static void vti_tunnel_setup(struct net_device *dev) 385 { 386 dev->netdev_ops = &vti_netdev_ops; 387 dev->type = ARPHRD_TUNNEL; 388 ip_tunnel_setup(dev, vti_net_id); 389 } 390 391 static int vti_tunnel_init(struct net_device *dev) 392 { 393 struct ip_tunnel *tunnel = netdev_priv(dev); 394 struct iphdr *iph = &tunnel->parms.iph; 395 396 memcpy(dev->dev_addr, &iph->saddr, 4); 397 memcpy(dev->broadcast, &iph->daddr, 4); 398 399 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 400 dev->mtu = ETH_DATA_LEN; 401 dev->flags = IFF_NOARP; 402 dev->addr_len = 4; 403 dev->features |= NETIF_F_LLTX; 404 netif_keep_dst(dev); 405 406 return ip_tunnel_init(dev); 407 } 408 409 static void __net_init vti_fb_tunnel_init(struct net_device *dev) 410 { 411 struct ip_tunnel *tunnel = netdev_priv(dev); 412 struct iphdr *iph = &tunnel->parms.iph; 413 414 iph->version = 4; 415 iph->protocol = IPPROTO_IPIP; 416 iph->ihl = 5; 417 } 418 419 static struct xfrm4_protocol vti_esp4_protocol __read_mostly = { 420 .handler = vti_rcv, 421 .input_handler = vti_input, 422 .cb_handler = vti_rcv_cb, 423 .err_handler = vti4_err, 424 .priority = 100, 425 }; 426 427 static struct xfrm4_protocol vti_ah4_protocol __read_mostly = { 428 .handler = vti_rcv, 429 .input_handler = vti_input, 430 .cb_handler = vti_rcv_cb, 431 .err_handler = vti4_err, 432 .priority = 100, 433 }; 434 435 static struct xfrm4_protocol vti_ipcomp4_protocol __read_mostly = { 436 .handler = vti_rcv, 437 .input_handler = vti_input, 438 .cb_handler = vti_rcv_cb, 439 .err_handler = vti4_err, 440 .priority = 100, 441 }; 442 443 static int __net_init vti_init_net(struct net *net) 444 { 445 int err; 446 struct ip_tunnel_net *itn; 447 448 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0"); 449 if (err) 450 return err; 451 itn = net_generic(net, vti_net_id); 452 vti_fb_tunnel_init(itn->fb_tunnel_dev); 453 return 0; 454 } 455 456 static void __net_exit vti_exit_net(struct net *net) 457 { 458 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 459 ip_tunnel_delete_net(itn, &vti_link_ops); 460 } 461 462 static struct pernet_operations vti_net_ops = { 463 .init = vti_init_net, 464 .exit = vti_exit_net, 465 .id = &vti_net_id, 466 .size = sizeof(struct ip_tunnel_net), 467 }; 468 469 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[], 470 struct netlink_ext_ack *extack) 471 { 472 return 0; 473 } 474 475 static void vti_netlink_parms(struct nlattr *data[], 476 struct ip_tunnel_parm *parms, 477 __u32 *fwmark) 478 { 479 memset(parms, 0, sizeof(*parms)); 480 481 parms->iph.protocol = IPPROTO_IPIP; 482 483 if (!data) 484 return; 485 486 parms->i_flags = VTI_ISVTI; 487 488 if (data[IFLA_VTI_LINK]) 489 parms->link = nla_get_u32(data[IFLA_VTI_LINK]); 490 491 if (data[IFLA_VTI_IKEY]) 492 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]); 493 494 if (data[IFLA_VTI_OKEY]) 495 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]); 496 497 if (data[IFLA_VTI_LOCAL]) 498 parms->iph.saddr = nla_get_in_addr(data[IFLA_VTI_LOCAL]); 499 500 if (data[IFLA_VTI_REMOTE]) 501 parms->iph.daddr = nla_get_in_addr(data[IFLA_VTI_REMOTE]); 502 503 if (data[IFLA_VTI_FWMARK]) 504 *fwmark = nla_get_u32(data[IFLA_VTI_FWMARK]); 505 } 506 507 static int vti_newlink(struct net *src_net, struct net_device *dev, 508 struct nlattr *tb[], struct nlattr *data[], 509 struct netlink_ext_ack *extack) 510 { 511 struct ip_tunnel_parm parms; 512 __u32 fwmark = 0; 513 514 vti_netlink_parms(data, &parms, &fwmark); 515 return ip_tunnel_newlink(dev, tb, &parms, fwmark); 516 } 517 518 static int vti_changelink(struct net_device *dev, struct nlattr *tb[], 519 struct nlattr *data[], 520 struct netlink_ext_ack *extack) 521 { 522 struct ip_tunnel *t = netdev_priv(dev); 523 __u32 fwmark = t->fwmark; 524 struct ip_tunnel_parm p; 525 526 vti_netlink_parms(data, &p, &fwmark); 527 return ip_tunnel_changelink(dev, tb, &p, fwmark); 528 } 529 530 static size_t vti_get_size(const struct net_device *dev) 531 { 532 return 533 /* IFLA_VTI_LINK */ 534 nla_total_size(4) + 535 /* IFLA_VTI_IKEY */ 536 nla_total_size(4) + 537 /* IFLA_VTI_OKEY */ 538 nla_total_size(4) + 539 /* IFLA_VTI_LOCAL */ 540 nla_total_size(4) + 541 /* IFLA_VTI_REMOTE */ 542 nla_total_size(4) + 543 /* IFLA_VTI_FWMARK */ 544 nla_total_size(4) + 545 0; 546 } 547 548 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev) 549 { 550 struct ip_tunnel *t = netdev_priv(dev); 551 struct ip_tunnel_parm *p = &t->parms; 552 553 if (nla_put_u32(skb, IFLA_VTI_LINK, p->link) || 554 nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key) || 555 nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key) || 556 nla_put_in_addr(skb, IFLA_VTI_LOCAL, p->iph.saddr) || 557 nla_put_in_addr(skb, IFLA_VTI_REMOTE, p->iph.daddr) || 558 nla_put_u32(skb, IFLA_VTI_FWMARK, t->fwmark)) 559 return -EMSGSIZE; 560 561 return 0; 562 } 563 564 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = { 565 [IFLA_VTI_LINK] = { .type = NLA_U32 }, 566 [IFLA_VTI_IKEY] = { .type = NLA_U32 }, 567 [IFLA_VTI_OKEY] = { .type = NLA_U32 }, 568 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 569 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 570 [IFLA_VTI_FWMARK] = { .type = NLA_U32 }, 571 }; 572 573 static struct rtnl_link_ops vti_link_ops __read_mostly = { 574 .kind = "vti", 575 .maxtype = IFLA_VTI_MAX, 576 .policy = vti_policy, 577 .priv_size = sizeof(struct ip_tunnel), 578 .setup = vti_tunnel_setup, 579 .validate = vti_tunnel_validate, 580 .newlink = vti_newlink, 581 .changelink = vti_changelink, 582 .dellink = ip_tunnel_dellink, 583 .get_size = vti_get_size, 584 .fill_info = vti_fill_info, 585 .get_link_net = ip_tunnel_get_link_net, 586 }; 587 588 static int __init vti_init(void) 589 { 590 const char *msg; 591 int err; 592 593 pr_info("IPv4 over IPsec tunneling driver\n"); 594 595 msg = "tunnel device"; 596 err = register_pernet_device(&vti_net_ops); 597 if (err < 0) 598 goto pernet_dev_failed; 599 600 msg = "tunnel protocols"; 601 err = xfrm4_protocol_register(&vti_esp4_protocol, IPPROTO_ESP); 602 if (err < 0) 603 goto xfrm_proto_esp_failed; 604 err = xfrm4_protocol_register(&vti_ah4_protocol, IPPROTO_AH); 605 if (err < 0) 606 goto xfrm_proto_ah_failed; 607 err = xfrm4_protocol_register(&vti_ipcomp4_protocol, IPPROTO_COMP); 608 if (err < 0) 609 goto xfrm_proto_comp_failed; 610 611 msg = "netlink interface"; 612 err = rtnl_link_register(&vti_link_ops); 613 if (err < 0) 614 goto rtnl_link_failed; 615 616 return err; 617 618 rtnl_link_failed: 619 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 620 xfrm_proto_comp_failed: 621 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 622 xfrm_proto_ah_failed: 623 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 624 xfrm_proto_esp_failed: 625 unregister_pernet_device(&vti_net_ops); 626 pernet_dev_failed: 627 pr_err("vti init: failed to register %s\n", msg); 628 return err; 629 } 630 631 static void __exit vti_fini(void) 632 { 633 rtnl_link_unregister(&vti_link_ops); 634 xfrm4_protocol_deregister(&vti_ipcomp4_protocol, IPPROTO_COMP); 635 xfrm4_protocol_deregister(&vti_ah4_protocol, IPPROTO_AH); 636 xfrm4_protocol_deregister(&vti_esp4_protocol, IPPROTO_ESP); 637 unregister_pernet_device(&vti_net_ops); 638 } 639 640 module_init(vti_init); 641 module_exit(vti_fini); 642 MODULE_LICENSE("GPL"); 643 MODULE_ALIAS_RTNL_LINK("vti"); 644 MODULE_ALIAS_NETDEV("ip_vti0"); 645