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 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_err(struct sk_buff *skb, u32 info) 53 { 54 55 /* All the routers (except for Linux) return only 56 * 8 bytes of packet payload. It means, that precise relaying of 57 * ICMP in the real Internet is absolutely infeasible. 58 */ 59 struct net *net = dev_net(skb->dev); 60 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 61 struct iphdr *iph = (struct iphdr *)skb->data; 62 const int type = icmp_hdr(skb)->type; 63 const int code = icmp_hdr(skb)->code; 64 struct ip_tunnel *t; 65 int err; 66 67 switch (type) { 68 default: 69 case ICMP_PARAMETERPROB: 70 return 0; 71 72 case ICMP_DEST_UNREACH: 73 switch (code) { 74 case ICMP_SR_FAILED: 75 case ICMP_PORT_UNREACH: 76 /* Impossible event. */ 77 return 0; 78 default: 79 /* All others are translated to HOST_UNREACH. */ 80 break; 81 } 82 break; 83 case ICMP_TIME_EXCEEDED: 84 if (code != ICMP_EXC_TTL) 85 return 0; 86 break; 87 } 88 89 err = -ENOENT; 90 91 t = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 92 iph->daddr, iph->saddr, 0); 93 if (t == NULL) 94 goto out; 95 96 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { 97 ipv4_update_pmtu(skb, dev_net(skb->dev), info, 98 t->parms.link, 0, IPPROTO_IPIP, 0); 99 err = 0; 100 goto out; 101 } 102 103 err = 0; 104 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) 105 goto out; 106 107 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) 108 t->err_count++; 109 else 110 t->err_count = 1; 111 t->err_time = jiffies; 112 out: 113 return err; 114 } 115 116 /* We dont digest the packet therefore let the packet pass */ 117 static int vti_rcv(struct sk_buff *skb) 118 { 119 struct ip_tunnel *tunnel; 120 const struct iphdr *iph = ip_hdr(skb); 121 struct net *net = dev_net(skb->dev); 122 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 123 124 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, TUNNEL_NO_KEY, 125 iph->saddr, iph->daddr, 0); 126 if (tunnel != NULL) { 127 struct pcpu_tstats *tstats; 128 129 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) 130 return -1; 131 132 tstats = this_cpu_ptr(tunnel->dev->tstats); 133 u64_stats_update_begin(&tstats->syncp); 134 tstats->rx_packets++; 135 tstats->rx_bytes += skb->len; 136 u64_stats_update_end(&tstats->syncp); 137 138 skb->mark = 0; 139 secpath_reset(skb); 140 skb->dev = tunnel->dev; 141 return 1; 142 } 143 144 return -1; 145 } 146 147 /* This function assumes it is being called from dev_queue_xmit() 148 * and that skb is filled properly by that function. 149 */ 150 151 static netdev_tx_t vti_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 152 { 153 struct ip_tunnel *tunnel = netdev_priv(dev); 154 struct iphdr *tiph = &tunnel->parms.iph; 155 u8 tos; 156 struct rtable *rt; /* Route to the other host */ 157 struct net_device *tdev; /* Device to other host */ 158 struct iphdr *old_iph = ip_hdr(skb); 159 __be32 dst = tiph->daddr; 160 struct flowi4 fl4; 161 int err; 162 163 if (skb->protocol != htons(ETH_P_IP)) 164 goto tx_error; 165 166 tos = old_iph->tos; 167 168 memset(&fl4, 0, sizeof(fl4)); 169 flowi4_init_output(&fl4, tunnel->parms.link, 170 be32_to_cpu(tunnel->parms.i_key), RT_TOS(tos), 171 RT_SCOPE_UNIVERSE, 172 IPPROTO_IPIP, 0, 173 dst, tiph->saddr, 0, 0); 174 rt = ip_route_output_key(dev_net(dev), &fl4); 175 if (IS_ERR(rt)) { 176 dev->stats.tx_carrier_errors++; 177 goto tx_error_icmp; 178 } 179 /* if there is no transform then this tunnel is not functional. 180 * Or if the xfrm is not mode tunnel. 181 */ 182 if (!rt->dst.xfrm || 183 rt->dst.xfrm->props.mode != XFRM_MODE_TUNNEL) { 184 dev->stats.tx_carrier_errors++; 185 goto tx_error_icmp; 186 } 187 tdev = rt->dst.dev; 188 189 if (tdev == dev) { 190 ip_rt_put(rt); 191 dev->stats.collisions++; 192 goto tx_error; 193 } 194 195 if (tunnel->err_count > 0) { 196 if (time_before(jiffies, 197 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) { 198 tunnel->err_count--; 199 dst_link_failure(skb); 200 } else 201 tunnel->err_count = 0; 202 } 203 204 memset(IPCB(skb), 0, sizeof(*IPCB(skb))); 205 skb_dst_drop(skb); 206 skb_dst_set(skb, &rt->dst); 207 nf_reset(skb); 208 skb->dev = skb_dst(skb)->dev; 209 210 err = dst_output(skb); 211 if (net_xmit_eval(err) == 0) 212 err = skb->len; 213 iptunnel_xmit_stats(err, &dev->stats, dev->tstats); 214 return NETDEV_TX_OK; 215 216 tx_error_icmp: 217 dst_link_failure(skb); 218 tx_error: 219 dev->stats.tx_errors++; 220 dev_kfree_skb(skb); 221 return NETDEV_TX_OK; 222 } 223 224 static int 225 vti_tunnel_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd) 226 { 227 int err = 0; 228 struct ip_tunnel_parm p; 229 230 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 231 return -EFAULT; 232 233 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 234 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP || 235 p.iph.ihl != 5) 236 return -EINVAL; 237 } 238 239 err = ip_tunnel_ioctl(dev, &p, cmd); 240 if (err) 241 return err; 242 243 if (cmd != SIOCDELTUNNEL) { 244 p.i_flags |= GRE_KEY | VTI_ISVTI; 245 p.o_flags |= GRE_KEY; 246 } 247 248 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 249 return -EFAULT; 250 return 0; 251 } 252 253 static const struct net_device_ops vti_netdev_ops = { 254 .ndo_init = vti_tunnel_init, 255 .ndo_uninit = ip_tunnel_uninit, 256 .ndo_start_xmit = vti_tunnel_xmit, 257 .ndo_do_ioctl = vti_tunnel_ioctl, 258 .ndo_change_mtu = ip_tunnel_change_mtu, 259 .ndo_get_stats64 = ip_tunnel_get_stats64, 260 }; 261 262 static void vti_tunnel_setup(struct net_device *dev) 263 { 264 dev->netdev_ops = &vti_netdev_ops; 265 ip_tunnel_setup(dev, vti_net_id); 266 } 267 268 static int vti_tunnel_init(struct net_device *dev) 269 { 270 struct ip_tunnel *tunnel = netdev_priv(dev); 271 struct iphdr *iph = &tunnel->parms.iph; 272 273 memcpy(dev->dev_addr, &iph->saddr, 4); 274 memcpy(dev->broadcast, &iph->daddr, 4); 275 276 dev->type = ARPHRD_TUNNEL; 277 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 278 dev->mtu = ETH_DATA_LEN; 279 dev->flags = IFF_NOARP; 280 dev->iflink = 0; 281 dev->addr_len = 4; 282 dev->features |= NETIF_F_NETNS_LOCAL; 283 dev->features |= NETIF_F_LLTX; 284 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; 285 286 return ip_tunnel_init(dev); 287 } 288 289 static void __net_init vti_fb_tunnel_init(struct net_device *dev) 290 { 291 struct ip_tunnel *tunnel = netdev_priv(dev); 292 struct iphdr *iph = &tunnel->parms.iph; 293 294 iph->version = 4; 295 iph->protocol = IPPROTO_IPIP; 296 iph->ihl = 5; 297 } 298 299 static struct xfrm_tunnel vti_handler __read_mostly = { 300 .handler = vti_rcv, 301 .err_handler = vti_err, 302 .priority = 1, 303 }; 304 305 static int __net_init vti_init_net(struct net *net) 306 { 307 int err; 308 struct ip_tunnel_net *itn; 309 310 err = ip_tunnel_init_net(net, vti_net_id, &vti_link_ops, "ip_vti0"); 311 if (err) 312 return err; 313 itn = net_generic(net, vti_net_id); 314 vti_fb_tunnel_init(itn->fb_tunnel_dev); 315 return 0; 316 } 317 318 static void __net_exit vti_exit_net(struct net *net) 319 { 320 struct ip_tunnel_net *itn = net_generic(net, vti_net_id); 321 ip_tunnel_delete_net(itn, &vti_link_ops); 322 } 323 324 static struct pernet_operations vti_net_ops = { 325 .init = vti_init_net, 326 .exit = vti_exit_net, 327 .id = &vti_net_id, 328 .size = sizeof(struct ip_tunnel_net), 329 }; 330 331 static int vti_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) 332 { 333 return 0; 334 } 335 336 static void vti_netlink_parms(struct nlattr *data[], 337 struct ip_tunnel_parm *parms) 338 { 339 memset(parms, 0, sizeof(*parms)); 340 341 parms->iph.protocol = IPPROTO_IPIP; 342 343 if (!data) 344 return; 345 346 if (data[IFLA_VTI_LINK]) 347 parms->link = nla_get_u32(data[IFLA_VTI_LINK]); 348 349 if (data[IFLA_VTI_IKEY]) 350 parms->i_key = nla_get_be32(data[IFLA_VTI_IKEY]); 351 352 if (data[IFLA_VTI_OKEY]) 353 parms->o_key = nla_get_be32(data[IFLA_VTI_OKEY]); 354 355 if (data[IFLA_VTI_LOCAL]) 356 parms->iph.saddr = nla_get_be32(data[IFLA_VTI_LOCAL]); 357 358 if (data[IFLA_VTI_REMOTE]) 359 parms->iph.daddr = nla_get_be32(data[IFLA_VTI_REMOTE]); 360 361 } 362 363 static int vti_newlink(struct net *src_net, struct net_device *dev, 364 struct nlattr *tb[], struct nlattr *data[]) 365 { 366 struct ip_tunnel_parm parms; 367 368 vti_netlink_parms(data, &parms); 369 return ip_tunnel_newlink(dev, tb, &parms); 370 } 371 372 static int vti_changelink(struct net_device *dev, struct nlattr *tb[], 373 struct nlattr *data[]) 374 { 375 struct ip_tunnel_parm p; 376 377 vti_netlink_parms(data, &p); 378 return ip_tunnel_changelink(dev, tb, &p); 379 } 380 381 static size_t vti_get_size(const struct net_device *dev) 382 { 383 return 384 /* IFLA_VTI_LINK */ 385 nla_total_size(4) + 386 /* IFLA_VTI_IKEY */ 387 nla_total_size(4) + 388 /* IFLA_VTI_OKEY */ 389 nla_total_size(4) + 390 /* IFLA_VTI_LOCAL */ 391 nla_total_size(4) + 392 /* IFLA_VTI_REMOTE */ 393 nla_total_size(4) + 394 0; 395 } 396 397 static int vti_fill_info(struct sk_buff *skb, const struct net_device *dev) 398 { 399 struct ip_tunnel *t = netdev_priv(dev); 400 struct ip_tunnel_parm *p = &t->parms; 401 402 nla_put_u32(skb, IFLA_VTI_LINK, p->link); 403 nla_put_be32(skb, IFLA_VTI_IKEY, p->i_key); 404 nla_put_be32(skb, IFLA_VTI_OKEY, p->o_key); 405 nla_put_be32(skb, IFLA_VTI_LOCAL, p->iph.saddr); 406 nla_put_be32(skb, IFLA_VTI_REMOTE, p->iph.daddr); 407 408 return 0; 409 } 410 411 static const struct nla_policy vti_policy[IFLA_VTI_MAX + 1] = { 412 [IFLA_VTI_LINK] = { .type = NLA_U32 }, 413 [IFLA_VTI_IKEY] = { .type = NLA_U32 }, 414 [IFLA_VTI_OKEY] = { .type = NLA_U32 }, 415 [IFLA_VTI_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 416 [IFLA_VTI_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 417 }; 418 419 static struct rtnl_link_ops vti_link_ops __read_mostly = { 420 .kind = "vti", 421 .maxtype = IFLA_VTI_MAX, 422 .policy = vti_policy, 423 .priv_size = sizeof(struct ip_tunnel), 424 .setup = vti_tunnel_setup, 425 .validate = vti_tunnel_validate, 426 .newlink = vti_newlink, 427 .changelink = vti_changelink, 428 .get_size = vti_get_size, 429 .fill_info = vti_fill_info, 430 }; 431 432 static int __init vti_init(void) 433 { 434 int err; 435 436 pr_info("IPv4 over IPSec tunneling driver\n"); 437 438 err = register_pernet_device(&vti_net_ops); 439 if (err < 0) 440 return err; 441 err = xfrm4_mode_tunnel_input_register(&vti_handler); 442 if (err < 0) { 443 unregister_pernet_device(&vti_net_ops); 444 pr_info("vti init: can't register tunnel\n"); 445 } 446 447 err = rtnl_link_register(&vti_link_ops); 448 if (err < 0) 449 goto rtnl_link_failed; 450 451 return err; 452 453 rtnl_link_failed: 454 xfrm4_mode_tunnel_input_deregister(&vti_handler); 455 unregister_pernet_device(&vti_net_ops); 456 return err; 457 } 458 459 static void __exit vti_fini(void) 460 { 461 rtnl_link_unregister(&vti_link_ops); 462 if (xfrm4_mode_tunnel_input_deregister(&vti_handler)) 463 pr_info("vti close: can't deregister tunnel\n"); 464 465 unregister_pernet_device(&vti_net_ops); 466 } 467 468 module_init(vti_init); 469 module_exit(vti_fini); 470 MODULE_LICENSE("GPL"); 471 MODULE_ALIAS_RTNL_LINK("vti"); 472 MODULE_ALIAS_NETDEV("ip_vti0"); 473