1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Linux NET3: GRE over IP protocol decoder. 4 * 5 * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/capability.h> 11 #include <linux/module.h> 12 #include <linux/types.h> 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <linux/uaccess.h> 16 #include <linux/skbuff.h> 17 #include <linux/netdevice.h> 18 #include <linux/in.h> 19 #include <linux/tcp.h> 20 #include <linux/udp.h> 21 #include <linux/if_arp.h> 22 #include <linux/if_vlan.h> 23 #include <linux/init.h> 24 #include <linux/in6.h> 25 #include <linux/inetdevice.h> 26 #include <linux/igmp.h> 27 #include <linux/netfilter_ipv4.h> 28 #include <linux/etherdevice.h> 29 #include <linux/if_ether.h> 30 31 #include <net/sock.h> 32 #include <net/ip.h> 33 #include <net/icmp.h> 34 #include <net/protocol.h> 35 #include <net/ip_tunnels.h> 36 #include <net/arp.h> 37 #include <net/checksum.h> 38 #include <net/dsfield.h> 39 #include <net/inet_ecn.h> 40 #include <net/xfrm.h> 41 #include <net/net_namespace.h> 42 #include <net/netns/generic.h> 43 #include <net/rtnetlink.h> 44 #include <net/gre.h> 45 #include <net/dst_metadata.h> 46 #include <net/erspan.h> 47 #include <net/inet_dscp.h> 48 49 /* 50 Problems & solutions 51 -------------------- 52 53 1. The most important issue is detecting local dead loops. 54 They would cause complete host lockup in transmit, which 55 would be "resolved" by stack overflow or, if queueing is enabled, 56 with infinite looping in net_bh. 57 58 We cannot track such dead loops during route installation, 59 it is infeasible task. The most general solutions would be 60 to keep skb->encapsulation counter (sort of local ttl), 61 and silently drop packet when it expires. It is a good 62 solution, but it supposes maintaining new variable in ALL 63 skb, even if no tunneling is used. 64 65 Current solution: xmit_recursion breaks dead loops. This is a percpu 66 counter, since when we enter the first ndo_xmit(), cpu migration is 67 forbidden. We force an exit if this counter reaches RECURSION_LIMIT 68 69 2. Networking dead loops would not kill routers, but would really 70 kill network. IP hop limit plays role of "t->recursion" in this case, 71 if we copy it from packet being encapsulated to upper header. 72 It is very good solution, but it introduces two problems: 73 74 - Routing protocols, using packets with ttl=1 (OSPF, RIP2), 75 do not work over tunnels. 76 - traceroute does not work. I planned to relay ICMP from tunnel, 77 so that this problem would be solved and traceroute output 78 would even more informative. This idea appeared to be wrong: 79 only Linux complies to rfc1812 now (yes, guys, Linux is the only 80 true router now :-)), all routers (at least, in neighbourhood of mine) 81 return only 8 bytes of payload. It is the end. 82 83 Hence, if we want that OSPF worked or traceroute said something reasonable, 84 we should search for another solution. 85 86 One of them is to parse packet trying to detect inner encapsulation 87 made by our node. It is difficult or even impossible, especially, 88 taking into account fragmentation. TO be short, ttl is not solution at all. 89 90 Current solution: The solution was UNEXPECTEDLY SIMPLE. 91 We force DF flag on tunnels with preconfigured hop limit, 92 that is ALL. :-) Well, it does not remove the problem completely, 93 but exponential growth of network traffic is changed to linear 94 (branches, that exceed pmtu are pruned) and tunnel mtu 95 rapidly degrades to value <68, where looping stops. 96 Yes, it is not good if there exists a router in the loop, 97 which does not force DF, even when encapsulating packets have DF set. 98 But it is not our problem! Nobody could accuse us, we made 99 all that we could make. Even if it is your gated who injected 100 fatal route to network, even if it were you who configured 101 fatal static route: you are innocent. :-) 102 103 Alexey Kuznetsov. 104 */ 105 106 static bool log_ecn_error = true; 107 module_param(log_ecn_error, bool, 0644); 108 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN"); 109 110 static struct rtnl_link_ops ipgre_link_ops __read_mostly; 111 static const struct header_ops ipgre_header_ops; 112 113 static int ipgre_tunnel_init(struct net_device *dev); 114 static void erspan_build_header(struct sk_buff *skb, 115 u32 id, u32 index, 116 bool truncate, bool is_ipv4); 117 118 static unsigned int ipgre_net_id __read_mostly; 119 static unsigned int gre_tap_net_id __read_mostly; 120 static unsigned int erspan_net_id __read_mostly; 121 122 static int ipgre_err(struct sk_buff *skb, u32 info, 123 const struct tnl_ptk_info *tpi) 124 { 125 126 /* All the routers (except for Linux) return only 127 8 bytes of packet payload. It means, that precise relaying of 128 ICMP in the real Internet is absolutely infeasible. 129 130 Moreover, Cisco "wise men" put GRE key to the third word 131 in GRE header. It makes impossible maintaining even soft 132 state for keyed GRE tunnels with enabled checksum. Tell 133 them "thank you". 134 135 Well, I wonder, rfc1812 was written by Cisco employee, 136 what the hell these idiots break standards established 137 by themselves??? 138 */ 139 struct net *net = dev_net(skb->dev); 140 struct ip_tunnel_net *itn; 141 const struct iphdr *iph; 142 const int type = icmp_hdr(skb)->type; 143 const int code = icmp_hdr(skb)->code; 144 unsigned int data_len = 0; 145 struct ip_tunnel *t; 146 147 if (tpi->proto == htons(ETH_P_TEB)) 148 itn = net_generic(net, gre_tap_net_id); 149 else if (tpi->proto == htons(ETH_P_ERSPAN) || 150 tpi->proto == htons(ETH_P_ERSPAN2)) 151 itn = net_generic(net, erspan_net_id); 152 else 153 itn = net_generic(net, ipgre_net_id); 154 155 iph = (const struct iphdr *)(icmp_hdr(skb) + 1); 156 t = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags, 157 iph->daddr, iph->saddr, tpi->key); 158 159 if (!t) 160 return -ENOENT; 161 162 switch (type) { 163 default: 164 case ICMP_PARAMETERPROB: 165 return 0; 166 167 case ICMP_DEST_UNREACH: 168 switch (code) { 169 case ICMP_SR_FAILED: 170 case ICMP_PORT_UNREACH: 171 /* Impossible event. */ 172 return 0; 173 default: 174 /* All others are translated to HOST_UNREACH. 175 rfc2003 contains "deep thoughts" about NET_UNREACH, 176 I believe they are just ether pollution. --ANK 177 */ 178 break; 179 } 180 break; 181 182 case ICMP_TIME_EXCEEDED: 183 if (code != ICMP_EXC_TTL) 184 return 0; 185 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */ 186 break; 187 188 case ICMP_REDIRECT: 189 break; 190 } 191 192 #if IS_ENABLED(CONFIG_IPV6) 193 if (tpi->proto == htons(ETH_P_IPV6) && 194 !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4 + tpi->hdr_len, 195 type, data_len)) 196 return 0; 197 #endif 198 199 if (t->parms.iph.daddr == 0 || 200 ipv4_is_multicast(t->parms.iph.daddr)) 201 return 0; 202 203 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) 204 return 0; 205 206 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) 207 t->err_count++; 208 else 209 t->err_count = 1; 210 t->err_time = jiffies; 211 212 return 0; 213 } 214 215 static void gre_err(struct sk_buff *skb, u32 info) 216 { 217 /* All the routers (except for Linux) return only 218 * 8 bytes of packet payload. It means, that precise relaying of 219 * ICMP in the real Internet is absolutely infeasible. 220 * 221 * Moreover, Cisco "wise men" put GRE key to the third word 222 * in GRE header. It makes impossible maintaining even soft 223 * state for keyed 224 * GRE tunnels with enabled checksum. Tell them "thank you". 225 * 226 * Well, I wonder, rfc1812 was written by Cisco employee, 227 * what the hell these idiots break standards established 228 * by themselves??? 229 */ 230 231 const struct iphdr *iph = (struct iphdr *)skb->data; 232 const int type = icmp_hdr(skb)->type; 233 const int code = icmp_hdr(skb)->code; 234 struct tnl_ptk_info tpi; 235 236 if (gre_parse_header(skb, &tpi, NULL, htons(ETH_P_IP), 237 iph->ihl * 4) < 0) 238 return; 239 240 if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) { 241 ipv4_update_pmtu(skb, dev_net(skb->dev), info, 242 skb->dev->ifindex, IPPROTO_GRE); 243 return; 244 } 245 if (type == ICMP_REDIRECT) { 246 ipv4_redirect(skb, dev_net(skb->dev), skb->dev->ifindex, 247 IPPROTO_GRE); 248 return; 249 } 250 251 ipgre_err(skb, info, &tpi); 252 } 253 254 static bool is_erspan_type1(int gre_hdr_len) 255 { 256 /* Both ERSPAN type I (version 0) and type II (version 1) use 257 * protocol 0x88BE, but the type I has only 4-byte GRE header, 258 * while type II has 8-byte. 259 */ 260 return gre_hdr_len == 4; 261 } 262 263 static int erspan_rcv(struct sk_buff *skb, struct tnl_ptk_info *tpi, 264 int gre_hdr_len) 265 { 266 struct net *net = dev_net(skb->dev); 267 struct metadata_dst *tun_dst = NULL; 268 struct erspan_base_hdr *ershdr; 269 IP_TUNNEL_DECLARE_FLAGS(flags); 270 struct ip_tunnel_net *itn; 271 struct ip_tunnel *tunnel; 272 const struct iphdr *iph; 273 struct erspan_md2 *md2; 274 int ver; 275 int len; 276 277 ip_tunnel_flags_copy(flags, tpi->flags); 278 279 itn = net_generic(net, erspan_net_id); 280 iph = ip_hdr(skb); 281 if (is_erspan_type1(gre_hdr_len)) { 282 ver = 0; 283 __set_bit(IP_TUNNEL_NO_KEY_BIT, flags); 284 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, flags, 285 iph->saddr, iph->daddr, 0); 286 } else { 287 if (unlikely(!pskb_may_pull(skb, 288 gre_hdr_len + sizeof(*ershdr)))) 289 return PACKET_REJECT; 290 291 ershdr = (struct erspan_base_hdr *)(skb->data + gre_hdr_len); 292 ver = ershdr->ver; 293 iph = ip_hdr(skb); 294 __set_bit(IP_TUNNEL_KEY_BIT, flags); 295 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, flags, 296 iph->saddr, iph->daddr, tpi->key); 297 } 298 299 if (tunnel) { 300 if (is_erspan_type1(gre_hdr_len)) 301 len = gre_hdr_len; 302 else 303 len = gre_hdr_len + erspan_hdr_len(ver); 304 305 if (unlikely(!pskb_may_pull(skb, len))) 306 return PACKET_REJECT; 307 308 if (__iptunnel_pull_header(skb, 309 len, 310 htons(ETH_P_TEB), 311 false, false) < 0) 312 goto drop; 313 314 if (tunnel->collect_md) { 315 struct erspan_metadata *pkt_md, *md; 316 struct ip_tunnel_info *info; 317 unsigned char *gh; 318 __be64 tun_id; 319 320 __set_bit(IP_TUNNEL_KEY_BIT, tpi->flags); 321 ip_tunnel_flags_copy(flags, tpi->flags); 322 tun_id = key32_to_tunnel_id(tpi->key); 323 324 tun_dst = ip_tun_rx_dst(skb, flags, 325 tun_id, sizeof(*md)); 326 if (!tun_dst) 327 return PACKET_REJECT; 328 329 /* skb can be uncloned in __iptunnel_pull_header, so 330 * old pkt_md is no longer valid and we need to reset 331 * it 332 */ 333 gh = skb_network_header(skb) + 334 skb_network_header_len(skb); 335 pkt_md = (struct erspan_metadata *)(gh + gre_hdr_len + 336 sizeof(*ershdr)); 337 md = ip_tunnel_info_opts(&tun_dst->u.tun_info); 338 md->version = ver; 339 md2 = &md->u.md2; 340 memcpy(md2, pkt_md, ver == 1 ? ERSPAN_V1_MDSIZE : 341 ERSPAN_V2_MDSIZE); 342 343 info = &tun_dst->u.tun_info; 344 __set_bit(IP_TUNNEL_ERSPAN_OPT_BIT, 345 info->key.tun_flags); 346 info->options_len = sizeof(*md); 347 } 348 349 skb_reset_mac_header(skb); 350 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); 351 return PACKET_RCVD; 352 } 353 return PACKET_REJECT; 354 355 drop: 356 kfree_skb(skb); 357 return PACKET_RCVD; 358 } 359 360 static int __ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi, 361 struct ip_tunnel_net *itn, int hdr_len, bool raw_proto) 362 { 363 struct metadata_dst *tun_dst = NULL; 364 const struct iphdr *iph; 365 struct ip_tunnel *tunnel; 366 367 iph = ip_hdr(skb); 368 tunnel = ip_tunnel_lookup(itn, skb->dev->ifindex, tpi->flags, 369 iph->saddr, iph->daddr, tpi->key); 370 371 if (tunnel) { 372 const struct iphdr *tnl_params; 373 374 if (__iptunnel_pull_header(skb, hdr_len, tpi->proto, 375 raw_proto, false) < 0) 376 goto drop; 377 378 /* Special case for ipgre_header_parse(), which expects the 379 * mac_header to point to the outer IP header. 380 */ 381 if (tunnel->dev->header_ops == &ipgre_header_ops) 382 skb_pop_mac_header(skb); 383 else 384 skb_reset_mac_header(skb); 385 386 tnl_params = &tunnel->parms.iph; 387 if (tunnel->collect_md || tnl_params->daddr == 0) { 388 IP_TUNNEL_DECLARE_FLAGS(flags) = { }; 389 __be64 tun_id; 390 391 __set_bit(IP_TUNNEL_CSUM_BIT, flags); 392 __set_bit(IP_TUNNEL_KEY_BIT, flags); 393 ip_tunnel_flags_and(flags, tpi->flags, flags); 394 395 tun_id = key32_to_tunnel_id(tpi->key); 396 tun_dst = ip_tun_rx_dst(skb, flags, tun_id, 0); 397 if (!tun_dst) 398 return PACKET_REJECT; 399 } 400 401 ip_tunnel_rcv(tunnel, skb, tpi, tun_dst, log_ecn_error); 402 return PACKET_RCVD; 403 } 404 return PACKET_NEXT; 405 406 drop: 407 kfree_skb(skb); 408 return PACKET_RCVD; 409 } 410 411 static int ipgre_rcv(struct sk_buff *skb, const struct tnl_ptk_info *tpi, 412 int hdr_len) 413 { 414 struct net *net = dev_net(skb->dev); 415 struct ip_tunnel_net *itn; 416 int res; 417 418 if (tpi->proto == htons(ETH_P_TEB)) 419 itn = net_generic(net, gre_tap_net_id); 420 else 421 itn = net_generic(net, ipgre_net_id); 422 423 res = __ipgre_rcv(skb, tpi, itn, hdr_len, false); 424 if (res == PACKET_NEXT && tpi->proto == htons(ETH_P_TEB)) { 425 /* ipgre tunnels in collect metadata mode should receive 426 * also ETH_P_TEB traffic. 427 */ 428 itn = net_generic(net, ipgre_net_id); 429 res = __ipgre_rcv(skb, tpi, itn, hdr_len, true); 430 } 431 return res; 432 } 433 434 static int gre_rcv(struct sk_buff *skb) 435 { 436 struct tnl_ptk_info tpi; 437 bool csum_err = false; 438 int hdr_len; 439 440 #ifdef CONFIG_NET_IPGRE_BROADCAST 441 if (ipv4_is_multicast(ip_hdr(skb)->daddr)) { 442 /* Looped back packet, drop it! */ 443 if (rt_is_output_route(skb_rtable(skb))) 444 goto drop; 445 } 446 #endif 447 448 hdr_len = gre_parse_header(skb, &tpi, &csum_err, htons(ETH_P_IP), 0); 449 if (hdr_len < 0) 450 goto drop; 451 452 if (unlikely(tpi.proto == htons(ETH_P_ERSPAN) || 453 tpi.proto == htons(ETH_P_ERSPAN2))) { 454 if (erspan_rcv(skb, &tpi, hdr_len) == PACKET_RCVD) 455 return 0; 456 goto out; 457 } 458 459 if (ipgre_rcv(skb, &tpi, hdr_len) == PACKET_RCVD) 460 return 0; 461 462 out: 463 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); 464 drop: 465 kfree_skb(skb); 466 return 0; 467 } 468 469 static void __gre_xmit(struct sk_buff *skb, struct net_device *dev, 470 const struct iphdr *tnl_params, 471 __be16 proto) 472 { 473 struct ip_tunnel *tunnel = netdev_priv(dev); 474 IP_TUNNEL_DECLARE_FLAGS(flags); 475 476 ip_tunnel_flags_copy(flags, tunnel->parms.o_flags); 477 478 /* Push GRE header. */ 479 gre_build_header(skb, tunnel->tun_hlen, 480 flags, proto, tunnel->parms.o_key, 481 test_bit(IP_TUNNEL_SEQ_BIT, flags) ? 482 htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0); 483 484 ip_tunnel_xmit(skb, dev, tnl_params, tnl_params->protocol); 485 } 486 487 static int gre_handle_offloads(struct sk_buff *skb, bool csum) 488 { 489 return iptunnel_handle_offloads(skb, csum ? SKB_GSO_GRE_CSUM : SKB_GSO_GRE); 490 } 491 492 static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev, 493 __be16 proto) 494 { 495 struct ip_tunnel *tunnel = netdev_priv(dev); 496 IP_TUNNEL_DECLARE_FLAGS(flags) = { }; 497 struct ip_tunnel_info *tun_info; 498 const struct ip_tunnel_key *key; 499 int tunnel_hlen; 500 501 tun_info = skb_tunnel_info(skb); 502 if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) || 503 ip_tunnel_info_af(tun_info) != AF_INET)) 504 goto err_free_skb; 505 506 key = &tun_info->key; 507 tunnel_hlen = gre_calc_hlen(key->tun_flags); 508 509 if (skb_cow_head(skb, dev->needed_headroom)) 510 goto err_free_skb; 511 512 /* Push Tunnel header. */ 513 if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, 514 tunnel->parms.o_flags))) 515 goto err_free_skb; 516 517 __set_bit(IP_TUNNEL_CSUM_BIT, flags); 518 __set_bit(IP_TUNNEL_KEY_BIT, flags); 519 __set_bit(IP_TUNNEL_SEQ_BIT, flags); 520 ip_tunnel_flags_and(flags, tun_info->key.tun_flags, flags); 521 522 gre_build_header(skb, tunnel_hlen, flags, proto, 523 tunnel_id_to_key32(tun_info->key.tun_id), 524 test_bit(IP_TUNNEL_SEQ_BIT, flags) ? 525 htonl(atomic_fetch_inc(&tunnel->o_seqno)) : 0); 526 527 ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen); 528 529 return; 530 531 err_free_skb: 532 kfree_skb(skb); 533 DEV_STATS_INC(dev, tx_dropped); 534 } 535 536 static void erspan_fb_xmit(struct sk_buff *skb, struct net_device *dev) 537 { 538 struct ip_tunnel *tunnel = netdev_priv(dev); 539 IP_TUNNEL_DECLARE_FLAGS(flags) = { }; 540 struct ip_tunnel_info *tun_info; 541 const struct ip_tunnel_key *key; 542 struct erspan_metadata *md; 543 bool truncate = false; 544 __be16 proto; 545 int tunnel_hlen; 546 int version; 547 int nhoff; 548 549 tun_info = skb_tunnel_info(skb); 550 if (unlikely(!tun_info || !(tun_info->mode & IP_TUNNEL_INFO_TX) || 551 ip_tunnel_info_af(tun_info) != AF_INET)) 552 goto err_free_skb; 553 554 key = &tun_info->key; 555 if (!test_bit(IP_TUNNEL_ERSPAN_OPT_BIT, tun_info->key.tun_flags)) 556 goto err_free_skb; 557 if (tun_info->options_len < sizeof(*md)) 558 goto err_free_skb; 559 md = ip_tunnel_info_opts(tun_info); 560 561 /* ERSPAN has fixed 8 byte GRE header */ 562 version = md->version; 563 tunnel_hlen = 8 + erspan_hdr_len(version); 564 565 if (skb_cow_head(skb, dev->needed_headroom)) 566 goto err_free_skb; 567 568 if (gre_handle_offloads(skb, false)) 569 goto err_free_skb; 570 571 if (skb->len > dev->mtu + dev->hard_header_len) { 572 if (pskb_trim(skb, dev->mtu + dev->hard_header_len)) 573 goto err_free_skb; 574 truncate = true; 575 } 576 577 nhoff = skb_network_offset(skb); 578 if (skb->protocol == htons(ETH_P_IP) && 579 (ntohs(ip_hdr(skb)->tot_len) > skb->len - nhoff)) 580 truncate = true; 581 582 if (skb->protocol == htons(ETH_P_IPV6)) { 583 int thoff; 584 585 if (skb_transport_header_was_set(skb)) 586 thoff = skb_transport_offset(skb); 587 else 588 thoff = nhoff + sizeof(struct ipv6hdr); 589 if (ntohs(ipv6_hdr(skb)->payload_len) > skb->len - thoff) 590 truncate = true; 591 } 592 593 if (version == 1) { 594 erspan_build_header(skb, ntohl(tunnel_id_to_key32(key->tun_id)), 595 ntohl(md->u.index), truncate, true); 596 proto = htons(ETH_P_ERSPAN); 597 } else if (version == 2) { 598 erspan_build_header_v2(skb, 599 ntohl(tunnel_id_to_key32(key->tun_id)), 600 md->u.md2.dir, 601 get_hwid(&md->u.md2), 602 truncate, true); 603 proto = htons(ETH_P_ERSPAN2); 604 } else { 605 goto err_free_skb; 606 } 607 608 __set_bit(IP_TUNNEL_SEQ_BIT, flags); 609 gre_build_header(skb, 8, flags, proto, 0, 610 htonl(atomic_fetch_inc(&tunnel->o_seqno))); 611 612 ip_md_tunnel_xmit(skb, dev, IPPROTO_GRE, tunnel_hlen); 613 614 return; 615 616 err_free_skb: 617 kfree_skb(skb); 618 DEV_STATS_INC(dev, tx_dropped); 619 } 620 621 static int gre_fill_metadata_dst(struct net_device *dev, struct sk_buff *skb) 622 { 623 struct ip_tunnel_info *info = skb_tunnel_info(skb); 624 const struct ip_tunnel_key *key; 625 struct rtable *rt; 626 struct flowi4 fl4; 627 628 if (ip_tunnel_info_af(info) != AF_INET) 629 return -EINVAL; 630 631 key = &info->key; 632 ip_tunnel_init_flow(&fl4, IPPROTO_GRE, key->u.ipv4.dst, key->u.ipv4.src, 633 tunnel_id_to_key32(key->tun_id), 634 key->tos & ~INET_ECN_MASK, dev_net(dev), 0, 635 skb->mark, skb_get_hash(skb), key->flow_flags); 636 rt = ip_route_output_key(dev_net(dev), &fl4); 637 if (IS_ERR(rt)) 638 return PTR_ERR(rt); 639 640 ip_rt_put(rt); 641 info->key.u.ipv4.src = fl4.saddr; 642 return 0; 643 } 644 645 static netdev_tx_t ipgre_xmit(struct sk_buff *skb, 646 struct net_device *dev) 647 { 648 struct ip_tunnel *tunnel = netdev_priv(dev); 649 const struct iphdr *tnl_params; 650 651 if (!pskb_inet_may_pull(skb)) 652 goto free_skb; 653 654 if (tunnel->collect_md) { 655 gre_fb_xmit(skb, dev, skb->protocol); 656 return NETDEV_TX_OK; 657 } 658 659 if (dev->header_ops) { 660 int pull_len = tunnel->hlen + sizeof(struct iphdr); 661 662 if (skb_cow_head(skb, 0)) 663 goto free_skb; 664 665 if (!pskb_may_pull(skb, pull_len)) 666 goto free_skb; 667 668 tnl_params = (const struct iphdr *)skb->data; 669 670 /* ip_tunnel_xmit() needs skb->data pointing to gre header. */ 671 skb_pull(skb, pull_len); 672 skb_reset_mac_header(skb); 673 674 if (skb->ip_summed == CHECKSUM_PARTIAL && 675 skb_checksum_start(skb) < skb->data) 676 goto free_skb; 677 } else { 678 if (skb_cow_head(skb, dev->needed_headroom)) 679 goto free_skb; 680 681 tnl_params = &tunnel->parms.iph; 682 } 683 684 if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, 685 tunnel->parms.o_flags))) 686 goto free_skb; 687 688 __gre_xmit(skb, dev, tnl_params, skb->protocol); 689 return NETDEV_TX_OK; 690 691 free_skb: 692 kfree_skb(skb); 693 DEV_STATS_INC(dev, tx_dropped); 694 return NETDEV_TX_OK; 695 } 696 697 static netdev_tx_t erspan_xmit(struct sk_buff *skb, 698 struct net_device *dev) 699 { 700 struct ip_tunnel *tunnel = netdev_priv(dev); 701 bool truncate = false; 702 __be16 proto; 703 704 if (!pskb_inet_may_pull(skb)) 705 goto free_skb; 706 707 if (tunnel->collect_md) { 708 erspan_fb_xmit(skb, dev); 709 return NETDEV_TX_OK; 710 } 711 712 if (gre_handle_offloads(skb, false)) 713 goto free_skb; 714 715 if (skb_cow_head(skb, dev->needed_headroom)) 716 goto free_skb; 717 718 if (skb->len > dev->mtu + dev->hard_header_len) { 719 if (pskb_trim(skb, dev->mtu + dev->hard_header_len)) 720 goto free_skb; 721 truncate = true; 722 } 723 724 /* Push ERSPAN header */ 725 if (tunnel->erspan_ver == 0) { 726 proto = htons(ETH_P_ERSPAN); 727 __clear_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags); 728 } else if (tunnel->erspan_ver == 1) { 729 erspan_build_header(skb, ntohl(tunnel->parms.o_key), 730 tunnel->index, 731 truncate, true); 732 proto = htons(ETH_P_ERSPAN); 733 } else if (tunnel->erspan_ver == 2) { 734 erspan_build_header_v2(skb, ntohl(tunnel->parms.o_key), 735 tunnel->dir, tunnel->hwid, 736 truncate, true); 737 proto = htons(ETH_P_ERSPAN2); 738 } else { 739 goto free_skb; 740 } 741 742 __clear_bit(IP_TUNNEL_KEY_BIT, tunnel->parms.o_flags); 743 __gre_xmit(skb, dev, &tunnel->parms.iph, proto); 744 return NETDEV_TX_OK; 745 746 free_skb: 747 kfree_skb(skb); 748 DEV_STATS_INC(dev, tx_dropped); 749 return NETDEV_TX_OK; 750 } 751 752 static netdev_tx_t gre_tap_xmit(struct sk_buff *skb, 753 struct net_device *dev) 754 { 755 struct ip_tunnel *tunnel = netdev_priv(dev); 756 757 if (!pskb_inet_may_pull(skb)) 758 goto free_skb; 759 760 if (tunnel->collect_md) { 761 gre_fb_xmit(skb, dev, htons(ETH_P_TEB)); 762 return NETDEV_TX_OK; 763 } 764 765 if (gre_handle_offloads(skb, test_bit(IP_TUNNEL_CSUM_BIT, 766 tunnel->parms.o_flags))) 767 goto free_skb; 768 769 if (skb_cow_head(skb, dev->needed_headroom)) 770 goto free_skb; 771 772 __gre_xmit(skb, dev, &tunnel->parms.iph, htons(ETH_P_TEB)); 773 return NETDEV_TX_OK; 774 775 free_skb: 776 kfree_skb(skb); 777 DEV_STATS_INC(dev, tx_dropped); 778 return NETDEV_TX_OK; 779 } 780 781 static void ipgre_link_update(struct net_device *dev, bool set_mtu) 782 { 783 struct ip_tunnel *tunnel = netdev_priv(dev); 784 int len; 785 786 len = tunnel->tun_hlen; 787 tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags); 788 len = tunnel->tun_hlen - len; 789 tunnel->hlen = tunnel->hlen + len; 790 791 if (dev->header_ops) 792 dev->hard_header_len += len; 793 else 794 dev->needed_headroom += len; 795 796 if (set_mtu) 797 WRITE_ONCE(dev->mtu, max_t(int, dev->mtu - len, 68)); 798 799 if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags) || 800 (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.o_flags) && 801 tunnel->encap.type != TUNNEL_ENCAP_NONE)) { 802 dev->features &= ~NETIF_F_GSO_SOFTWARE; 803 dev->hw_features &= ~NETIF_F_GSO_SOFTWARE; 804 } else { 805 dev->features |= NETIF_F_GSO_SOFTWARE; 806 dev->hw_features |= NETIF_F_GSO_SOFTWARE; 807 } 808 } 809 810 static int ipgre_tunnel_ctl(struct net_device *dev, 811 struct ip_tunnel_parm_kern *p, 812 int cmd) 813 { 814 __be16 i_flags, o_flags; 815 int err; 816 817 if (!ip_tunnel_flags_is_be16_compat(p->i_flags) || 818 !ip_tunnel_flags_is_be16_compat(p->o_flags)) 819 return -EOVERFLOW; 820 821 i_flags = ip_tunnel_flags_to_be16(p->i_flags); 822 o_flags = ip_tunnel_flags_to_be16(p->o_flags); 823 824 if (cmd == SIOCADDTUNNEL || cmd == SIOCCHGTUNNEL) { 825 if (p->iph.version != 4 || p->iph.protocol != IPPROTO_GRE || 826 p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)) || 827 ((i_flags | o_flags) & (GRE_VERSION | GRE_ROUTING))) 828 return -EINVAL; 829 } 830 831 gre_flags_to_tnl_flags(p->i_flags, i_flags); 832 gre_flags_to_tnl_flags(p->o_flags, o_flags); 833 834 err = ip_tunnel_ctl(dev, p, cmd); 835 if (err) 836 return err; 837 838 if (cmd == SIOCCHGTUNNEL) { 839 struct ip_tunnel *t = netdev_priv(dev); 840 841 ip_tunnel_flags_copy(t->parms.i_flags, p->i_flags); 842 ip_tunnel_flags_copy(t->parms.o_flags, p->o_flags); 843 844 if (strcmp(dev->rtnl_link_ops->kind, "erspan")) 845 ipgre_link_update(dev, true); 846 } 847 848 i_flags = gre_tnl_flags_to_gre_flags(p->i_flags); 849 ip_tunnel_flags_from_be16(p->i_flags, i_flags); 850 o_flags = gre_tnl_flags_to_gre_flags(p->o_flags); 851 ip_tunnel_flags_from_be16(p->o_flags, o_flags); 852 853 return 0; 854 } 855 856 /* Nice toy. Unfortunately, useless in real life :-) 857 It allows to construct virtual multiprotocol broadcast "LAN" 858 over the Internet, provided multicast routing is tuned. 859 860 861 I have no idea was this bicycle invented before me, 862 so that I had to set ARPHRD_IPGRE to a random value. 863 I have an impression, that Cisco could make something similar, 864 but this feature is apparently missing in IOS<=11.2(8). 865 866 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks 867 with broadcast 224.66.66.66. If you have access to mbone, play with me :-) 868 869 ping -t 255 224.66.66.66 870 871 If nobody answers, mbone does not work. 872 873 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255 874 ip addr add 10.66.66.<somewhat>/24 dev Universe 875 ifconfig Universe up 876 ifconfig Universe add fe80::<Your_real_addr>/10 877 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96 878 ftp 10.66.66.66 879 ... 880 ftp fec0:6666:6666::193.233.7.65 881 ... 882 */ 883 static int ipgre_header(struct sk_buff *skb, struct net_device *dev, 884 unsigned short type, 885 const void *daddr, const void *saddr, unsigned int len) 886 { 887 struct ip_tunnel *t = netdev_priv(dev); 888 struct iphdr *iph; 889 struct gre_base_hdr *greh; 890 891 iph = skb_push(skb, t->hlen + sizeof(*iph)); 892 greh = (struct gre_base_hdr *)(iph+1); 893 greh->flags = gre_tnl_flags_to_gre_flags(t->parms.o_flags); 894 greh->protocol = htons(type); 895 896 memcpy(iph, &t->parms.iph, sizeof(struct iphdr)); 897 898 /* Set the source hardware address. */ 899 if (saddr) 900 memcpy(&iph->saddr, saddr, 4); 901 if (daddr) 902 memcpy(&iph->daddr, daddr, 4); 903 if (iph->daddr) 904 return t->hlen + sizeof(*iph); 905 906 return -(t->hlen + sizeof(*iph)); 907 } 908 909 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr) 910 { 911 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb); 912 memcpy(haddr, &iph->saddr, 4); 913 return 4; 914 } 915 916 static const struct header_ops ipgre_header_ops = { 917 .create = ipgre_header, 918 .parse = ipgre_header_parse, 919 }; 920 921 #ifdef CONFIG_NET_IPGRE_BROADCAST 922 static int ipgre_open(struct net_device *dev) 923 { 924 struct ip_tunnel *t = netdev_priv(dev); 925 926 if (ipv4_is_multicast(t->parms.iph.daddr)) { 927 struct flowi4 fl4; 928 struct rtable *rt; 929 930 rt = ip_route_output_gre(t->net, &fl4, 931 t->parms.iph.daddr, 932 t->parms.iph.saddr, 933 t->parms.o_key, 934 t->parms.iph.tos & INET_DSCP_MASK, 935 t->parms.link); 936 if (IS_ERR(rt)) 937 return -EADDRNOTAVAIL; 938 dev = rt->dst.dev; 939 ip_rt_put(rt); 940 if (!__in_dev_get_rtnl(dev)) 941 return -EADDRNOTAVAIL; 942 t->mlink = dev->ifindex; 943 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr); 944 } 945 return 0; 946 } 947 948 static int ipgre_close(struct net_device *dev) 949 { 950 struct ip_tunnel *t = netdev_priv(dev); 951 952 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) { 953 struct in_device *in_dev; 954 in_dev = inetdev_by_index(t->net, t->mlink); 955 if (in_dev) 956 ip_mc_dec_group(in_dev, t->parms.iph.daddr); 957 } 958 return 0; 959 } 960 #endif 961 962 static const struct net_device_ops ipgre_netdev_ops = { 963 .ndo_init = ipgre_tunnel_init, 964 .ndo_uninit = ip_tunnel_uninit, 965 #ifdef CONFIG_NET_IPGRE_BROADCAST 966 .ndo_open = ipgre_open, 967 .ndo_stop = ipgre_close, 968 #endif 969 .ndo_start_xmit = ipgre_xmit, 970 .ndo_siocdevprivate = ip_tunnel_siocdevprivate, 971 .ndo_change_mtu = ip_tunnel_change_mtu, 972 .ndo_get_stats64 = dev_get_tstats64, 973 .ndo_get_iflink = ip_tunnel_get_iflink, 974 .ndo_tunnel_ctl = ipgre_tunnel_ctl, 975 }; 976 977 #define GRE_FEATURES (NETIF_F_SG | \ 978 NETIF_F_FRAGLIST | \ 979 NETIF_F_HIGHDMA | \ 980 NETIF_F_HW_CSUM) 981 982 static void ipgre_tunnel_setup(struct net_device *dev) 983 { 984 dev->netdev_ops = &ipgre_netdev_ops; 985 dev->type = ARPHRD_IPGRE; 986 ip_tunnel_setup(dev, ipgre_net_id); 987 } 988 989 static void __gre_tunnel_init(struct net_device *dev) 990 { 991 struct ip_tunnel *tunnel; 992 993 tunnel = netdev_priv(dev); 994 tunnel->tun_hlen = gre_calc_hlen(tunnel->parms.o_flags); 995 tunnel->parms.iph.protocol = IPPROTO_GRE; 996 997 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen; 998 dev->needed_headroom = tunnel->hlen + sizeof(tunnel->parms.iph); 999 1000 dev->features |= GRE_FEATURES; 1001 dev->hw_features |= GRE_FEATURES; 1002 1003 /* TCP offload with GRE SEQ is not supported, nor can we support 2 1004 * levels of outer headers requiring an update. 1005 */ 1006 if (test_bit(IP_TUNNEL_SEQ_BIT, tunnel->parms.o_flags)) 1007 return; 1008 if (test_bit(IP_TUNNEL_CSUM_BIT, tunnel->parms.o_flags) && 1009 tunnel->encap.type != TUNNEL_ENCAP_NONE) 1010 return; 1011 1012 dev->features |= NETIF_F_GSO_SOFTWARE; 1013 dev->hw_features |= NETIF_F_GSO_SOFTWARE; 1014 1015 dev->lltx = true; 1016 } 1017 1018 static int ipgre_tunnel_init(struct net_device *dev) 1019 { 1020 struct ip_tunnel *tunnel = netdev_priv(dev); 1021 struct iphdr *iph = &tunnel->parms.iph; 1022 1023 __gre_tunnel_init(dev); 1024 1025 __dev_addr_set(dev, &iph->saddr, 4); 1026 memcpy(dev->broadcast, &iph->daddr, 4); 1027 1028 dev->flags = IFF_NOARP; 1029 netif_keep_dst(dev); 1030 dev->addr_len = 4; 1031 1032 if (iph->daddr && !tunnel->collect_md) { 1033 #ifdef CONFIG_NET_IPGRE_BROADCAST 1034 if (ipv4_is_multicast(iph->daddr)) { 1035 if (!iph->saddr) 1036 return -EINVAL; 1037 dev->flags = IFF_BROADCAST; 1038 dev->header_ops = &ipgre_header_ops; 1039 dev->hard_header_len = tunnel->hlen + sizeof(*iph); 1040 dev->needed_headroom = 0; 1041 } 1042 #endif 1043 } else if (!tunnel->collect_md) { 1044 dev->header_ops = &ipgre_header_ops; 1045 dev->hard_header_len = tunnel->hlen + sizeof(*iph); 1046 dev->needed_headroom = 0; 1047 } 1048 1049 return ip_tunnel_init(dev); 1050 } 1051 1052 static const struct gre_protocol ipgre_protocol = { 1053 .handler = gre_rcv, 1054 .err_handler = gre_err, 1055 }; 1056 1057 static int __net_init ipgre_init_net(struct net *net) 1058 { 1059 return ip_tunnel_init_net(net, ipgre_net_id, &ipgre_link_ops, NULL); 1060 } 1061 1062 static void __net_exit ipgre_exit_batch_rtnl(struct list_head *list_net, 1063 struct list_head *dev_to_kill) 1064 { 1065 ip_tunnel_delete_nets(list_net, ipgre_net_id, &ipgre_link_ops, 1066 dev_to_kill); 1067 } 1068 1069 static struct pernet_operations ipgre_net_ops = { 1070 .init = ipgre_init_net, 1071 .exit_batch_rtnl = ipgre_exit_batch_rtnl, 1072 .id = &ipgre_net_id, 1073 .size = sizeof(struct ip_tunnel_net), 1074 }; 1075 1076 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[], 1077 struct netlink_ext_ack *extack) 1078 { 1079 __be16 flags; 1080 1081 if (!data) 1082 return 0; 1083 1084 flags = 0; 1085 if (data[IFLA_GRE_IFLAGS]) 1086 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); 1087 if (data[IFLA_GRE_OFLAGS]) 1088 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); 1089 if (flags & (GRE_VERSION|GRE_ROUTING)) 1090 return -EINVAL; 1091 1092 if (data[IFLA_GRE_COLLECT_METADATA] && 1093 data[IFLA_GRE_ENCAP_TYPE] && 1094 nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]) != TUNNEL_ENCAP_NONE) 1095 return -EINVAL; 1096 1097 return 0; 1098 } 1099 1100 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[], 1101 struct netlink_ext_ack *extack) 1102 { 1103 __be32 daddr; 1104 1105 if (tb[IFLA_ADDRESS]) { 1106 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 1107 return -EINVAL; 1108 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 1109 return -EADDRNOTAVAIL; 1110 } 1111 1112 if (!data) 1113 goto out; 1114 1115 if (data[IFLA_GRE_REMOTE]) { 1116 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4); 1117 if (!daddr) 1118 return -EINVAL; 1119 } 1120 1121 out: 1122 return ipgre_tunnel_validate(tb, data, extack); 1123 } 1124 1125 static int erspan_validate(struct nlattr *tb[], struct nlattr *data[], 1126 struct netlink_ext_ack *extack) 1127 { 1128 __be16 flags = 0; 1129 int ret; 1130 1131 if (!data) 1132 return 0; 1133 1134 ret = ipgre_tap_validate(tb, data, extack); 1135 if (ret) 1136 return ret; 1137 1138 if (data[IFLA_GRE_ERSPAN_VER] && 1139 nla_get_u8(data[IFLA_GRE_ERSPAN_VER]) == 0) 1140 return 0; 1141 1142 /* ERSPAN type II/III should only have GRE sequence and key flag */ 1143 if (data[IFLA_GRE_OFLAGS]) 1144 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); 1145 if (data[IFLA_GRE_IFLAGS]) 1146 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); 1147 if (!data[IFLA_GRE_COLLECT_METADATA] && 1148 flags != (GRE_SEQ | GRE_KEY)) 1149 return -EINVAL; 1150 1151 /* ERSPAN Session ID only has 10-bit. Since we reuse 1152 * 32-bit key field as ID, check it's range. 1153 */ 1154 if (data[IFLA_GRE_IKEY] && 1155 (ntohl(nla_get_be32(data[IFLA_GRE_IKEY])) & ~ID_MASK)) 1156 return -EINVAL; 1157 1158 if (data[IFLA_GRE_OKEY] && 1159 (ntohl(nla_get_be32(data[IFLA_GRE_OKEY])) & ~ID_MASK)) 1160 return -EINVAL; 1161 1162 return 0; 1163 } 1164 1165 static int ipgre_netlink_parms(struct net_device *dev, 1166 struct nlattr *data[], 1167 struct nlattr *tb[], 1168 struct ip_tunnel_parm_kern *parms, 1169 __u32 *fwmark) 1170 { 1171 struct ip_tunnel *t = netdev_priv(dev); 1172 1173 memset(parms, 0, sizeof(*parms)); 1174 1175 parms->iph.protocol = IPPROTO_GRE; 1176 1177 if (!data) 1178 return 0; 1179 1180 if (data[IFLA_GRE_LINK]) 1181 parms->link = nla_get_u32(data[IFLA_GRE_LINK]); 1182 1183 if (data[IFLA_GRE_IFLAGS]) 1184 gre_flags_to_tnl_flags(parms->i_flags, 1185 nla_get_be16(data[IFLA_GRE_IFLAGS])); 1186 1187 if (data[IFLA_GRE_OFLAGS]) 1188 gre_flags_to_tnl_flags(parms->o_flags, 1189 nla_get_be16(data[IFLA_GRE_OFLAGS])); 1190 1191 if (data[IFLA_GRE_IKEY]) 1192 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]); 1193 1194 if (data[IFLA_GRE_OKEY]) 1195 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]); 1196 1197 if (data[IFLA_GRE_LOCAL]) 1198 parms->iph.saddr = nla_get_in_addr(data[IFLA_GRE_LOCAL]); 1199 1200 if (data[IFLA_GRE_REMOTE]) 1201 parms->iph.daddr = nla_get_in_addr(data[IFLA_GRE_REMOTE]); 1202 1203 if (data[IFLA_GRE_TTL]) 1204 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]); 1205 1206 if (data[IFLA_GRE_TOS]) 1207 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]); 1208 1209 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) { 1210 if (t->ignore_df) 1211 return -EINVAL; 1212 parms->iph.frag_off = htons(IP_DF); 1213 } 1214 1215 if (data[IFLA_GRE_COLLECT_METADATA]) { 1216 t->collect_md = true; 1217 if (dev->type == ARPHRD_IPGRE) 1218 dev->type = ARPHRD_NONE; 1219 } 1220 1221 if (data[IFLA_GRE_IGNORE_DF]) { 1222 if (nla_get_u8(data[IFLA_GRE_IGNORE_DF]) 1223 && (parms->iph.frag_off & htons(IP_DF))) 1224 return -EINVAL; 1225 t->ignore_df = !!nla_get_u8(data[IFLA_GRE_IGNORE_DF]); 1226 } 1227 1228 if (data[IFLA_GRE_FWMARK]) 1229 *fwmark = nla_get_u32(data[IFLA_GRE_FWMARK]); 1230 1231 return 0; 1232 } 1233 1234 static int erspan_netlink_parms(struct net_device *dev, 1235 struct nlattr *data[], 1236 struct nlattr *tb[], 1237 struct ip_tunnel_parm_kern *parms, 1238 __u32 *fwmark) 1239 { 1240 struct ip_tunnel *t = netdev_priv(dev); 1241 int err; 1242 1243 err = ipgre_netlink_parms(dev, data, tb, parms, fwmark); 1244 if (err) 1245 return err; 1246 if (!data) 1247 return 0; 1248 1249 if (data[IFLA_GRE_ERSPAN_VER]) { 1250 t->erspan_ver = nla_get_u8(data[IFLA_GRE_ERSPAN_VER]); 1251 1252 if (t->erspan_ver > 2) 1253 return -EINVAL; 1254 } 1255 1256 if (t->erspan_ver == 1) { 1257 if (data[IFLA_GRE_ERSPAN_INDEX]) { 1258 t->index = nla_get_u32(data[IFLA_GRE_ERSPAN_INDEX]); 1259 if (t->index & ~INDEX_MASK) 1260 return -EINVAL; 1261 } 1262 } else if (t->erspan_ver == 2) { 1263 if (data[IFLA_GRE_ERSPAN_DIR]) { 1264 t->dir = nla_get_u8(data[IFLA_GRE_ERSPAN_DIR]); 1265 if (t->dir & ~(DIR_MASK >> DIR_OFFSET)) 1266 return -EINVAL; 1267 } 1268 if (data[IFLA_GRE_ERSPAN_HWID]) { 1269 t->hwid = nla_get_u16(data[IFLA_GRE_ERSPAN_HWID]); 1270 if (t->hwid & ~(HWID_MASK >> HWID_OFFSET)) 1271 return -EINVAL; 1272 } 1273 } 1274 1275 return 0; 1276 } 1277 1278 /* This function returns true when ENCAP attributes are present in the nl msg */ 1279 static bool ipgre_netlink_encap_parms(struct nlattr *data[], 1280 struct ip_tunnel_encap *ipencap) 1281 { 1282 bool ret = false; 1283 1284 memset(ipencap, 0, sizeof(*ipencap)); 1285 1286 if (!data) 1287 return ret; 1288 1289 if (data[IFLA_GRE_ENCAP_TYPE]) { 1290 ret = true; 1291 ipencap->type = nla_get_u16(data[IFLA_GRE_ENCAP_TYPE]); 1292 } 1293 1294 if (data[IFLA_GRE_ENCAP_FLAGS]) { 1295 ret = true; 1296 ipencap->flags = nla_get_u16(data[IFLA_GRE_ENCAP_FLAGS]); 1297 } 1298 1299 if (data[IFLA_GRE_ENCAP_SPORT]) { 1300 ret = true; 1301 ipencap->sport = nla_get_be16(data[IFLA_GRE_ENCAP_SPORT]); 1302 } 1303 1304 if (data[IFLA_GRE_ENCAP_DPORT]) { 1305 ret = true; 1306 ipencap->dport = nla_get_be16(data[IFLA_GRE_ENCAP_DPORT]); 1307 } 1308 1309 return ret; 1310 } 1311 1312 static int gre_tap_init(struct net_device *dev) 1313 { 1314 __gre_tunnel_init(dev); 1315 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1316 netif_keep_dst(dev); 1317 1318 return ip_tunnel_init(dev); 1319 } 1320 1321 static const struct net_device_ops gre_tap_netdev_ops = { 1322 .ndo_init = gre_tap_init, 1323 .ndo_uninit = ip_tunnel_uninit, 1324 .ndo_start_xmit = gre_tap_xmit, 1325 .ndo_set_mac_address = eth_mac_addr, 1326 .ndo_validate_addr = eth_validate_addr, 1327 .ndo_change_mtu = ip_tunnel_change_mtu, 1328 .ndo_get_stats64 = dev_get_tstats64, 1329 .ndo_get_iflink = ip_tunnel_get_iflink, 1330 .ndo_fill_metadata_dst = gre_fill_metadata_dst, 1331 }; 1332 1333 static int erspan_tunnel_init(struct net_device *dev) 1334 { 1335 struct ip_tunnel *tunnel = netdev_priv(dev); 1336 1337 if (tunnel->erspan_ver == 0) 1338 tunnel->tun_hlen = 4; /* 4-byte GRE hdr. */ 1339 else 1340 tunnel->tun_hlen = 8; /* 8-byte GRE hdr. */ 1341 1342 tunnel->parms.iph.protocol = IPPROTO_GRE; 1343 tunnel->hlen = tunnel->tun_hlen + tunnel->encap_hlen + 1344 erspan_hdr_len(tunnel->erspan_ver); 1345 1346 dev->features |= GRE_FEATURES; 1347 dev->hw_features |= GRE_FEATURES; 1348 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1349 netif_keep_dst(dev); 1350 1351 return ip_tunnel_init(dev); 1352 } 1353 1354 static const struct net_device_ops erspan_netdev_ops = { 1355 .ndo_init = erspan_tunnel_init, 1356 .ndo_uninit = ip_tunnel_uninit, 1357 .ndo_start_xmit = erspan_xmit, 1358 .ndo_set_mac_address = eth_mac_addr, 1359 .ndo_validate_addr = eth_validate_addr, 1360 .ndo_change_mtu = ip_tunnel_change_mtu, 1361 .ndo_get_stats64 = dev_get_tstats64, 1362 .ndo_get_iflink = ip_tunnel_get_iflink, 1363 .ndo_fill_metadata_dst = gre_fill_metadata_dst, 1364 }; 1365 1366 static void ipgre_tap_setup(struct net_device *dev) 1367 { 1368 ether_setup(dev); 1369 dev->max_mtu = 0; 1370 dev->netdev_ops = &gre_tap_netdev_ops; 1371 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 1372 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1373 ip_tunnel_setup(dev, gre_tap_net_id); 1374 } 1375 1376 static int 1377 ipgre_newlink_encap_setup(struct net_device *dev, struct nlattr *data[]) 1378 { 1379 struct ip_tunnel_encap ipencap; 1380 1381 if (ipgre_netlink_encap_parms(data, &ipencap)) { 1382 struct ip_tunnel *t = netdev_priv(dev); 1383 int err = ip_tunnel_encap_setup(t, &ipencap); 1384 1385 if (err < 0) 1386 return err; 1387 } 1388 1389 return 0; 1390 } 1391 1392 static int ipgre_newlink(struct net *src_net, struct net_device *dev, 1393 struct nlattr *tb[], struct nlattr *data[], 1394 struct netlink_ext_ack *extack) 1395 { 1396 struct ip_tunnel_parm_kern p; 1397 __u32 fwmark = 0; 1398 int err; 1399 1400 err = ipgre_newlink_encap_setup(dev, data); 1401 if (err) 1402 return err; 1403 1404 err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark); 1405 if (err < 0) 1406 return err; 1407 return ip_tunnel_newlink(dev, tb, &p, fwmark); 1408 } 1409 1410 static int erspan_newlink(struct net *src_net, struct net_device *dev, 1411 struct nlattr *tb[], struct nlattr *data[], 1412 struct netlink_ext_ack *extack) 1413 { 1414 struct ip_tunnel_parm_kern p; 1415 __u32 fwmark = 0; 1416 int err; 1417 1418 err = ipgre_newlink_encap_setup(dev, data); 1419 if (err) 1420 return err; 1421 1422 err = erspan_netlink_parms(dev, data, tb, &p, &fwmark); 1423 if (err) 1424 return err; 1425 return ip_tunnel_newlink(dev, tb, &p, fwmark); 1426 } 1427 1428 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 1429 struct nlattr *data[], 1430 struct netlink_ext_ack *extack) 1431 { 1432 struct ip_tunnel *t = netdev_priv(dev); 1433 struct ip_tunnel_parm_kern p; 1434 __u32 fwmark = t->fwmark; 1435 int err; 1436 1437 err = ipgre_newlink_encap_setup(dev, data); 1438 if (err) 1439 return err; 1440 1441 err = ipgre_netlink_parms(dev, data, tb, &p, &fwmark); 1442 if (err < 0) 1443 return err; 1444 1445 err = ip_tunnel_changelink(dev, tb, &p, fwmark); 1446 if (err < 0) 1447 return err; 1448 1449 ip_tunnel_flags_copy(t->parms.i_flags, p.i_flags); 1450 ip_tunnel_flags_copy(t->parms.o_flags, p.o_flags); 1451 1452 ipgre_link_update(dev, !tb[IFLA_MTU]); 1453 1454 return 0; 1455 } 1456 1457 static int erspan_changelink(struct net_device *dev, struct nlattr *tb[], 1458 struct nlattr *data[], 1459 struct netlink_ext_ack *extack) 1460 { 1461 struct ip_tunnel *t = netdev_priv(dev); 1462 struct ip_tunnel_parm_kern p; 1463 __u32 fwmark = t->fwmark; 1464 int err; 1465 1466 err = ipgre_newlink_encap_setup(dev, data); 1467 if (err) 1468 return err; 1469 1470 err = erspan_netlink_parms(dev, data, tb, &p, &fwmark); 1471 if (err < 0) 1472 return err; 1473 1474 err = ip_tunnel_changelink(dev, tb, &p, fwmark); 1475 if (err < 0) 1476 return err; 1477 1478 ip_tunnel_flags_copy(t->parms.i_flags, p.i_flags); 1479 ip_tunnel_flags_copy(t->parms.o_flags, p.o_flags); 1480 1481 return 0; 1482 } 1483 1484 static size_t ipgre_get_size(const struct net_device *dev) 1485 { 1486 return 1487 /* IFLA_GRE_LINK */ 1488 nla_total_size(4) + 1489 /* IFLA_GRE_IFLAGS */ 1490 nla_total_size(2) + 1491 /* IFLA_GRE_OFLAGS */ 1492 nla_total_size(2) + 1493 /* IFLA_GRE_IKEY */ 1494 nla_total_size(4) + 1495 /* IFLA_GRE_OKEY */ 1496 nla_total_size(4) + 1497 /* IFLA_GRE_LOCAL */ 1498 nla_total_size(4) + 1499 /* IFLA_GRE_REMOTE */ 1500 nla_total_size(4) + 1501 /* IFLA_GRE_TTL */ 1502 nla_total_size(1) + 1503 /* IFLA_GRE_TOS */ 1504 nla_total_size(1) + 1505 /* IFLA_GRE_PMTUDISC */ 1506 nla_total_size(1) + 1507 /* IFLA_GRE_ENCAP_TYPE */ 1508 nla_total_size(2) + 1509 /* IFLA_GRE_ENCAP_FLAGS */ 1510 nla_total_size(2) + 1511 /* IFLA_GRE_ENCAP_SPORT */ 1512 nla_total_size(2) + 1513 /* IFLA_GRE_ENCAP_DPORT */ 1514 nla_total_size(2) + 1515 /* IFLA_GRE_COLLECT_METADATA */ 1516 nla_total_size(0) + 1517 /* IFLA_GRE_IGNORE_DF */ 1518 nla_total_size(1) + 1519 /* IFLA_GRE_FWMARK */ 1520 nla_total_size(4) + 1521 /* IFLA_GRE_ERSPAN_INDEX */ 1522 nla_total_size(4) + 1523 /* IFLA_GRE_ERSPAN_VER */ 1524 nla_total_size(1) + 1525 /* IFLA_GRE_ERSPAN_DIR */ 1526 nla_total_size(1) + 1527 /* IFLA_GRE_ERSPAN_HWID */ 1528 nla_total_size(2) + 1529 0; 1530 } 1531 1532 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev) 1533 { 1534 struct ip_tunnel *t = netdev_priv(dev); 1535 struct ip_tunnel_parm_kern *p = &t->parms; 1536 IP_TUNNEL_DECLARE_FLAGS(o_flags); 1537 1538 ip_tunnel_flags_copy(o_flags, p->o_flags); 1539 1540 if (nla_put_u32(skb, IFLA_GRE_LINK, p->link) || 1541 nla_put_be16(skb, IFLA_GRE_IFLAGS, 1542 gre_tnl_flags_to_gre_flags(p->i_flags)) || 1543 nla_put_be16(skb, IFLA_GRE_OFLAGS, 1544 gre_tnl_flags_to_gre_flags(o_flags)) || 1545 nla_put_be32(skb, IFLA_GRE_IKEY, p->i_key) || 1546 nla_put_be32(skb, IFLA_GRE_OKEY, p->o_key) || 1547 nla_put_in_addr(skb, IFLA_GRE_LOCAL, p->iph.saddr) || 1548 nla_put_in_addr(skb, IFLA_GRE_REMOTE, p->iph.daddr) || 1549 nla_put_u8(skb, IFLA_GRE_TTL, p->iph.ttl) || 1550 nla_put_u8(skb, IFLA_GRE_TOS, p->iph.tos) || 1551 nla_put_u8(skb, IFLA_GRE_PMTUDISC, 1552 !!(p->iph.frag_off & htons(IP_DF))) || 1553 nla_put_u32(skb, IFLA_GRE_FWMARK, t->fwmark)) 1554 goto nla_put_failure; 1555 1556 if (nla_put_u16(skb, IFLA_GRE_ENCAP_TYPE, 1557 t->encap.type) || 1558 nla_put_be16(skb, IFLA_GRE_ENCAP_SPORT, 1559 t->encap.sport) || 1560 nla_put_be16(skb, IFLA_GRE_ENCAP_DPORT, 1561 t->encap.dport) || 1562 nla_put_u16(skb, IFLA_GRE_ENCAP_FLAGS, 1563 t->encap.flags)) 1564 goto nla_put_failure; 1565 1566 if (nla_put_u8(skb, IFLA_GRE_IGNORE_DF, t->ignore_df)) 1567 goto nla_put_failure; 1568 1569 if (t->collect_md) { 1570 if (nla_put_flag(skb, IFLA_GRE_COLLECT_METADATA)) 1571 goto nla_put_failure; 1572 } 1573 1574 return 0; 1575 1576 nla_put_failure: 1577 return -EMSGSIZE; 1578 } 1579 1580 static int erspan_fill_info(struct sk_buff *skb, const struct net_device *dev) 1581 { 1582 struct ip_tunnel *t = netdev_priv(dev); 1583 1584 if (t->erspan_ver <= 2) { 1585 if (t->erspan_ver != 0 && !t->collect_md) 1586 __set_bit(IP_TUNNEL_KEY_BIT, t->parms.o_flags); 1587 1588 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_VER, t->erspan_ver)) 1589 goto nla_put_failure; 1590 1591 if (t->erspan_ver == 1) { 1592 if (nla_put_u32(skb, IFLA_GRE_ERSPAN_INDEX, t->index)) 1593 goto nla_put_failure; 1594 } else if (t->erspan_ver == 2) { 1595 if (nla_put_u8(skb, IFLA_GRE_ERSPAN_DIR, t->dir)) 1596 goto nla_put_failure; 1597 if (nla_put_u16(skb, IFLA_GRE_ERSPAN_HWID, t->hwid)) 1598 goto nla_put_failure; 1599 } 1600 } 1601 1602 return ipgre_fill_info(skb, dev); 1603 1604 nla_put_failure: 1605 return -EMSGSIZE; 1606 } 1607 1608 static void erspan_setup(struct net_device *dev) 1609 { 1610 struct ip_tunnel *t = netdev_priv(dev); 1611 1612 ether_setup(dev); 1613 dev->max_mtu = 0; 1614 dev->netdev_ops = &erspan_netdev_ops; 1615 dev->priv_flags &= ~IFF_TX_SKB_SHARING; 1616 dev->priv_flags |= IFF_LIVE_ADDR_CHANGE; 1617 ip_tunnel_setup(dev, erspan_net_id); 1618 t->erspan_ver = 1; 1619 } 1620 1621 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = { 1622 [IFLA_GRE_LINK] = { .type = NLA_U32 }, 1623 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 }, 1624 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 }, 1625 [IFLA_GRE_IKEY] = { .type = NLA_U32 }, 1626 [IFLA_GRE_OKEY] = { .type = NLA_U32 }, 1627 [IFLA_GRE_LOCAL] = { .len = sizeof_field(struct iphdr, saddr) }, 1628 [IFLA_GRE_REMOTE] = { .len = sizeof_field(struct iphdr, daddr) }, 1629 [IFLA_GRE_TTL] = { .type = NLA_U8 }, 1630 [IFLA_GRE_TOS] = { .type = NLA_U8 }, 1631 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 }, 1632 [IFLA_GRE_ENCAP_TYPE] = { .type = NLA_U16 }, 1633 [IFLA_GRE_ENCAP_FLAGS] = { .type = NLA_U16 }, 1634 [IFLA_GRE_ENCAP_SPORT] = { .type = NLA_U16 }, 1635 [IFLA_GRE_ENCAP_DPORT] = { .type = NLA_U16 }, 1636 [IFLA_GRE_COLLECT_METADATA] = { .type = NLA_FLAG }, 1637 [IFLA_GRE_IGNORE_DF] = { .type = NLA_U8 }, 1638 [IFLA_GRE_FWMARK] = { .type = NLA_U32 }, 1639 [IFLA_GRE_ERSPAN_INDEX] = { .type = NLA_U32 }, 1640 [IFLA_GRE_ERSPAN_VER] = { .type = NLA_U8 }, 1641 [IFLA_GRE_ERSPAN_DIR] = { .type = NLA_U8 }, 1642 [IFLA_GRE_ERSPAN_HWID] = { .type = NLA_U16 }, 1643 }; 1644 1645 static struct rtnl_link_ops ipgre_link_ops __read_mostly = { 1646 .kind = "gre", 1647 .maxtype = IFLA_GRE_MAX, 1648 .policy = ipgre_policy, 1649 .priv_size = sizeof(struct ip_tunnel), 1650 .setup = ipgre_tunnel_setup, 1651 .validate = ipgre_tunnel_validate, 1652 .newlink = ipgre_newlink, 1653 .changelink = ipgre_changelink, 1654 .dellink = ip_tunnel_dellink, 1655 .get_size = ipgre_get_size, 1656 .fill_info = ipgre_fill_info, 1657 .get_link_net = ip_tunnel_get_link_net, 1658 }; 1659 1660 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = { 1661 .kind = "gretap", 1662 .maxtype = IFLA_GRE_MAX, 1663 .policy = ipgre_policy, 1664 .priv_size = sizeof(struct ip_tunnel), 1665 .setup = ipgre_tap_setup, 1666 .validate = ipgre_tap_validate, 1667 .newlink = ipgre_newlink, 1668 .changelink = ipgre_changelink, 1669 .dellink = ip_tunnel_dellink, 1670 .get_size = ipgre_get_size, 1671 .fill_info = ipgre_fill_info, 1672 .get_link_net = ip_tunnel_get_link_net, 1673 }; 1674 1675 static struct rtnl_link_ops erspan_link_ops __read_mostly = { 1676 .kind = "erspan", 1677 .maxtype = IFLA_GRE_MAX, 1678 .policy = ipgre_policy, 1679 .priv_size = sizeof(struct ip_tunnel), 1680 .setup = erspan_setup, 1681 .validate = erspan_validate, 1682 .newlink = erspan_newlink, 1683 .changelink = erspan_changelink, 1684 .dellink = ip_tunnel_dellink, 1685 .get_size = ipgre_get_size, 1686 .fill_info = erspan_fill_info, 1687 .get_link_net = ip_tunnel_get_link_net, 1688 }; 1689 1690 struct net_device *gretap_fb_dev_create(struct net *net, const char *name, 1691 u8 name_assign_type) 1692 { 1693 struct nlattr *tb[IFLA_MAX + 1]; 1694 struct net_device *dev; 1695 LIST_HEAD(list_kill); 1696 struct ip_tunnel *t; 1697 int err; 1698 1699 memset(&tb, 0, sizeof(tb)); 1700 1701 dev = rtnl_create_link(net, name, name_assign_type, 1702 &ipgre_tap_ops, tb, NULL); 1703 if (IS_ERR(dev)) 1704 return dev; 1705 1706 /* Configure flow based GRE device. */ 1707 t = netdev_priv(dev); 1708 t->collect_md = true; 1709 1710 err = ipgre_newlink(net, dev, tb, NULL, NULL); 1711 if (err < 0) { 1712 free_netdev(dev); 1713 return ERR_PTR(err); 1714 } 1715 1716 /* openvswitch users expect packet sizes to be unrestricted, 1717 * so set the largest MTU we can. 1718 */ 1719 err = __ip_tunnel_change_mtu(dev, IP_MAX_MTU, false); 1720 if (err) 1721 goto out; 1722 1723 err = rtnl_configure_link(dev, NULL, 0, NULL); 1724 if (err < 0) 1725 goto out; 1726 1727 return dev; 1728 out: 1729 ip_tunnel_dellink(dev, &list_kill); 1730 unregister_netdevice_many(&list_kill); 1731 return ERR_PTR(err); 1732 } 1733 EXPORT_SYMBOL_GPL(gretap_fb_dev_create); 1734 1735 static int __net_init ipgre_tap_init_net(struct net *net) 1736 { 1737 return ip_tunnel_init_net(net, gre_tap_net_id, &ipgre_tap_ops, "gretap0"); 1738 } 1739 1740 static void __net_exit ipgre_tap_exit_batch_rtnl(struct list_head *list_net, 1741 struct list_head *dev_to_kill) 1742 { 1743 ip_tunnel_delete_nets(list_net, gre_tap_net_id, &ipgre_tap_ops, 1744 dev_to_kill); 1745 } 1746 1747 static struct pernet_operations ipgre_tap_net_ops = { 1748 .init = ipgre_tap_init_net, 1749 .exit_batch_rtnl = ipgre_tap_exit_batch_rtnl, 1750 .id = &gre_tap_net_id, 1751 .size = sizeof(struct ip_tunnel_net), 1752 }; 1753 1754 static int __net_init erspan_init_net(struct net *net) 1755 { 1756 return ip_tunnel_init_net(net, erspan_net_id, 1757 &erspan_link_ops, "erspan0"); 1758 } 1759 1760 static void __net_exit erspan_exit_batch_rtnl(struct list_head *net_list, 1761 struct list_head *dev_to_kill) 1762 { 1763 ip_tunnel_delete_nets(net_list, erspan_net_id, &erspan_link_ops, 1764 dev_to_kill); 1765 } 1766 1767 static struct pernet_operations erspan_net_ops = { 1768 .init = erspan_init_net, 1769 .exit_batch_rtnl = erspan_exit_batch_rtnl, 1770 .id = &erspan_net_id, 1771 .size = sizeof(struct ip_tunnel_net), 1772 }; 1773 1774 static int __init ipgre_init(void) 1775 { 1776 int err; 1777 1778 pr_info("GRE over IPv4 tunneling driver\n"); 1779 1780 err = register_pernet_device(&ipgre_net_ops); 1781 if (err < 0) 1782 return err; 1783 1784 err = register_pernet_device(&ipgre_tap_net_ops); 1785 if (err < 0) 1786 goto pnet_tap_failed; 1787 1788 err = register_pernet_device(&erspan_net_ops); 1789 if (err < 0) 1790 goto pnet_erspan_failed; 1791 1792 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO); 1793 if (err < 0) { 1794 pr_info("%s: can't add protocol\n", __func__); 1795 goto add_proto_failed; 1796 } 1797 1798 err = rtnl_link_register(&ipgre_link_ops); 1799 if (err < 0) 1800 goto rtnl_link_failed; 1801 1802 err = rtnl_link_register(&ipgre_tap_ops); 1803 if (err < 0) 1804 goto tap_ops_failed; 1805 1806 err = rtnl_link_register(&erspan_link_ops); 1807 if (err < 0) 1808 goto erspan_link_failed; 1809 1810 return 0; 1811 1812 erspan_link_failed: 1813 rtnl_link_unregister(&ipgre_tap_ops); 1814 tap_ops_failed: 1815 rtnl_link_unregister(&ipgre_link_ops); 1816 rtnl_link_failed: 1817 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); 1818 add_proto_failed: 1819 unregister_pernet_device(&erspan_net_ops); 1820 pnet_erspan_failed: 1821 unregister_pernet_device(&ipgre_tap_net_ops); 1822 pnet_tap_failed: 1823 unregister_pernet_device(&ipgre_net_ops); 1824 return err; 1825 } 1826 1827 static void __exit ipgre_fini(void) 1828 { 1829 rtnl_link_unregister(&ipgre_tap_ops); 1830 rtnl_link_unregister(&ipgre_link_ops); 1831 rtnl_link_unregister(&erspan_link_ops); 1832 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); 1833 unregister_pernet_device(&ipgre_tap_net_ops); 1834 unregister_pernet_device(&ipgre_net_ops); 1835 unregister_pernet_device(&erspan_net_ops); 1836 } 1837 1838 module_init(ipgre_init); 1839 module_exit(ipgre_fini); 1840 MODULE_DESCRIPTION("IPv4 GRE tunnels over IP library"); 1841 MODULE_LICENSE("GPL"); 1842 MODULE_ALIAS_RTNL_LINK("gre"); 1843 MODULE_ALIAS_RTNL_LINK("gretap"); 1844 MODULE_ALIAS_RTNL_LINK("erspan"); 1845 MODULE_ALIAS_NETDEV("gre0"); 1846 MODULE_ALIAS_NETDEV("gretap0"); 1847 MODULE_ALIAS_NETDEV("erspan0"); 1848