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