1 /* 2 * Linux NET3: GRE over IP protocol decoder. 3 * 4 * Authors: Alexey Kuznetsov (kuznet@ms2.inr.ac.ru) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 * 11 */ 12 13 #include <linux/capability.h> 14 #include <linux/module.h> 15 #include <linux/types.h> 16 #include <linux/kernel.h> 17 #include <linux/slab.h> 18 #include <asm/uaccess.h> 19 #include <linux/skbuff.h> 20 #include <linux/netdevice.h> 21 #include <linux/in.h> 22 #include <linux/tcp.h> 23 #include <linux/udp.h> 24 #include <linux/if_arp.h> 25 #include <linux/mroute.h> 26 #include <linux/init.h> 27 #include <linux/in6.h> 28 #include <linux/inetdevice.h> 29 #include <linux/igmp.h> 30 #include <linux/netfilter_ipv4.h> 31 #include <linux/etherdevice.h> 32 #include <linux/if_ether.h> 33 34 #include <net/sock.h> 35 #include <net/ip.h> 36 #include <net/icmp.h> 37 #include <net/protocol.h> 38 #include <net/ipip.h> 39 #include <net/arp.h> 40 #include <net/checksum.h> 41 #include <net/dsfield.h> 42 #include <net/inet_ecn.h> 43 #include <net/xfrm.h> 44 #include <net/net_namespace.h> 45 #include <net/netns/generic.h> 46 #include <net/rtnetlink.h> 47 #include <net/gre.h> 48 49 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 50 #include <net/ipv6.h> 51 #include <net/ip6_fib.h> 52 #include <net/ip6_route.h> 53 #endif 54 55 /* 56 Problems & solutions 57 -------------------- 58 59 1. The most important issue is detecting local dead loops. 60 They would cause complete host lockup in transmit, which 61 would be "resolved" by stack overflow or, if queueing is enabled, 62 with infinite looping in net_bh. 63 64 We cannot track such dead loops during route installation, 65 it is infeasible task. The most general solutions would be 66 to keep skb->encapsulation counter (sort of local ttl), 67 and silently drop packet when it expires. It is a good 68 solution, but it supposes maintaing new variable in ALL 69 skb, even if no tunneling is used. 70 71 Current solution: xmit_recursion breaks dead loops. This is a percpu 72 counter, since when we enter the first ndo_xmit(), cpu migration is 73 forbidden. We force an exit if this counter reaches RECURSION_LIMIT 74 75 2. Networking dead loops would not kill routers, but would really 76 kill network. IP hop limit plays role of "t->recursion" in this case, 77 if we copy it from packet being encapsulated to upper header. 78 It is very good solution, but it introduces two problems: 79 80 - Routing protocols, using packets with ttl=1 (OSPF, RIP2), 81 do not work over tunnels. 82 - traceroute does not work. I planned to relay ICMP from tunnel, 83 so that this problem would be solved and traceroute output 84 would even more informative. This idea appeared to be wrong: 85 only Linux complies to rfc1812 now (yes, guys, Linux is the only 86 true router now :-)), all routers (at least, in neighbourhood of mine) 87 return only 8 bytes of payload. It is the end. 88 89 Hence, if we want that OSPF worked or traceroute said something reasonable, 90 we should search for another solution. 91 92 One of them is to parse packet trying to detect inner encapsulation 93 made by our node. It is difficult or even impossible, especially, 94 taking into account fragmentation. TO be short, tt is not solution at all. 95 96 Current solution: The solution was UNEXPECTEDLY SIMPLE. 97 We force DF flag on tunnels with preconfigured hop limit, 98 that is ALL. :-) Well, it does not remove the problem completely, 99 but exponential growth of network traffic is changed to linear 100 (branches, that exceed pmtu are pruned) and tunnel mtu 101 fastly degrades to value <68, where looping stops. 102 Yes, it is not good if there exists a router in the loop, 103 which does not force DF, even when encapsulating packets have DF set. 104 But it is not our problem! Nobody could accuse us, we made 105 all that we could make. Even if it is your gated who injected 106 fatal route to network, even if it were you who configured 107 fatal static route: you are innocent. :-) 108 109 110 111 3. Really, ipv4/ipip.c, ipv4/ip_gre.c and ipv6/sit.c contain 112 practically identical code. It would be good to glue them 113 together, but it is not very evident, how to make them modular. 114 sit is integral part of IPv6, ipip and gre are naturally modular. 115 We could extract common parts (hash table, ioctl etc) 116 to a separate module (ip_tunnel.c). 117 118 Alexey Kuznetsov. 119 */ 120 121 static struct rtnl_link_ops ipgre_link_ops __read_mostly; 122 static int ipgre_tunnel_init(struct net_device *dev); 123 static void ipgre_tunnel_setup(struct net_device *dev); 124 static int ipgre_tunnel_bind_dev(struct net_device *dev); 125 126 /* Fallback tunnel: no source, no destination, no key, no options */ 127 128 #define HASH_SIZE 16 129 130 static int ipgre_net_id __read_mostly; 131 struct ipgre_net { 132 struct ip_tunnel __rcu *tunnels[4][HASH_SIZE]; 133 134 struct net_device *fb_tunnel_dev; 135 }; 136 137 /* Tunnel hash table */ 138 139 /* 140 4 hash tables: 141 142 3: (remote,local) 143 2: (remote,*) 144 1: (*,local) 145 0: (*,*) 146 147 We require exact key match i.e. if a key is present in packet 148 it will match only tunnel with the same key; if it is not present, 149 it will match only keyless tunnel. 150 151 All keysless packets, if not matched configured keyless tunnels 152 will match fallback tunnel. 153 */ 154 155 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF) 156 157 #define tunnels_r_l tunnels[3] 158 #define tunnels_r tunnels[2] 159 #define tunnels_l tunnels[1] 160 #define tunnels_wc tunnels[0] 161 /* 162 * Locking : hash tables are protected by RCU and RTNL 163 */ 164 165 #define for_each_ip_tunnel_rcu(start) \ 166 for (t = rcu_dereference(start); t; t = rcu_dereference(t->next)) 167 168 /* often modified stats are per cpu, other are shared (netdev->stats) */ 169 struct pcpu_tstats { 170 unsigned long rx_packets; 171 unsigned long rx_bytes; 172 unsigned long tx_packets; 173 unsigned long tx_bytes; 174 }; 175 176 static struct net_device_stats *ipgre_get_stats(struct net_device *dev) 177 { 178 struct pcpu_tstats sum = { 0 }; 179 int i; 180 181 for_each_possible_cpu(i) { 182 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i); 183 184 sum.rx_packets += tstats->rx_packets; 185 sum.rx_bytes += tstats->rx_bytes; 186 sum.tx_packets += tstats->tx_packets; 187 sum.tx_bytes += tstats->tx_bytes; 188 } 189 dev->stats.rx_packets = sum.rx_packets; 190 dev->stats.rx_bytes = sum.rx_bytes; 191 dev->stats.tx_packets = sum.tx_packets; 192 dev->stats.tx_bytes = sum.tx_bytes; 193 return &dev->stats; 194 } 195 196 /* Given src, dst and key, find appropriate for input tunnel. */ 197 198 static struct ip_tunnel * ipgre_tunnel_lookup(struct net_device *dev, 199 __be32 remote, __be32 local, 200 __be32 key, __be16 gre_proto) 201 { 202 struct net *net = dev_net(dev); 203 int link = dev->ifindex; 204 unsigned int h0 = HASH(remote); 205 unsigned int h1 = HASH(key); 206 struct ip_tunnel *t, *cand = NULL; 207 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 208 int dev_type = (gre_proto == htons(ETH_P_TEB)) ? 209 ARPHRD_ETHER : ARPHRD_IPGRE; 210 int score, cand_score = 4; 211 212 for_each_ip_tunnel_rcu(ign->tunnels_r_l[h0 ^ h1]) { 213 if (local != t->parms.iph.saddr || 214 remote != t->parms.iph.daddr || 215 key != t->parms.i_key || 216 !(t->dev->flags & IFF_UP)) 217 continue; 218 219 if (t->dev->type != ARPHRD_IPGRE && 220 t->dev->type != dev_type) 221 continue; 222 223 score = 0; 224 if (t->parms.link != link) 225 score |= 1; 226 if (t->dev->type != dev_type) 227 score |= 2; 228 if (score == 0) 229 return t; 230 231 if (score < cand_score) { 232 cand = t; 233 cand_score = score; 234 } 235 } 236 237 for_each_ip_tunnel_rcu(ign->tunnels_r[h0 ^ h1]) { 238 if (remote != t->parms.iph.daddr || 239 key != t->parms.i_key || 240 !(t->dev->flags & IFF_UP)) 241 continue; 242 243 if (t->dev->type != ARPHRD_IPGRE && 244 t->dev->type != dev_type) 245 continue; 246 247 score = 0; 248 if (t->parms.link != link) 249 score |= 1; 250 if (t->dev->type != dev_type) 251 score |= 2; 252 if (score == 0) 253 return t; 254 255 if (score < cand_score) { 256 cand = t; 257 cand_score = score; 258 } 259 } 260 261 for_each_ip_tunnel_rcu(ign->tunnels_l[h1]) { 262 if ((local != t->parms.iph.saddr && 263 (local != t->parms.iph.daddr || 264 !ipv4_is_multicast(local))) || 265 key != t->parms.i_key || 266 !(t->dev->flags & IFF_UP)) 267 continue; 268 269 if (t->dev->type != ARPHRD_IPGRE && 270 t->dev->type != dev_type) 271 continue; 272 273 score = 0; 274 if (t->parms.link != link) 275 score |= 1; 276 if (t->dev->type != dev_type) 277 score |= 2; 278 if (score == 0) 279 return t; 280 281 if (score < cand_score) { 282 cand = t; 283 cand_score = score; 284 } 285 } 286 287 for_each_ip_tunnel_rcu(ign->tunnels_wc[h1]) { 288 if (t->parms.i_key != key || 289 !(t->dev->flags & IFF_UP)) 290 continue; 291 292 if (t->dev->type != ARPHRD_IPGRE && 293 t->dev->type != dev_type) 294 continue; 295 296 score = 0; 297 if (t->parms.link != link) 298 score |= 1; 299 if (t->dev->type != dev_type) 300 score |= 2; 301 if (score == 0) 302 return t; 303 304 if (score < cand_score) { 305 cand = t; 306 cand_score = score; 307 } 308 } 309 310 if (cand != NULL) 311 return cand; 312 313 dev = ign->fb_tunnel_dev; 314 if (dev->flags & IFF_UP) 315 return netdev_priv(dev); 316 317 return NULL; 318 } 319 320 static struct ip_tunnel __rcu **__ipgre_bucket(struct ipgre_net *ign, 321 struct ip_tunnel_parm *parms) 322 { 323 __be32 remote = parms->iph.daddr; 324 __be32 local = parms->iph.saddr; 325 __be32 key = parms->i_key; 326 unsigned int h = HASH(key); 327 int prio = 0; 328 329 if (local) 330 prio |= 1; 331 if (remote && !ipv4_is_multicast(remote)) { 332 prio |= 2; 333 h ^= HASH(remote); 334 } 335 336 return &ign->tunnels[prio][h]; 337 } 338 339 static inline struct ip_tunnel __rcu **ipgre_bucket(struct ipgre_net *ign, 340 struct ip_tunnel *t) 341 { 342 return __ipgre_bucket(ign, &t->parms); 343 } 344 345 static void ipgre_tunnel_link(struct ipgre_net *ign, struct ip_tunnel *t) 346 { 347 struct ip_tunnel __rcu **tp = ipgre_bucket(ign, t); 348 349 rcu_assign_pointer(t->next, rtnl_dereference(*tp)); 350 rcu_assign_pointer(*tp, t); 351 } 352 353 static void ipgre_tunnel_unlink(struct ipgre_net *ign, struct ip_tunnel *t) 354 { 355 struct ip_tunnel __rcu **tp; 356 struct ip_tunnel *iter; 357 358 for (tp = ipgre_bucket(ign, t); 359 (iter = rtnl_dereference(*tp)) != NULL; 360 tp = &iter->next) { 361 if (t == iter) { 362 rcu_assign_pointer(*tp, t->next); 363 break; 364 } 365 } 366 } 367 368 static struct ip_tunnel *ipgre_tunnel_find(struct net *net, 369 struct ip_tunnel_parm *parms, 370 int type) 371 { 372 __be32 remote = parms->iph.daddr; 373 __be32 local = parms->iph.saddr; 374 __be32 key = parms->i_key; 375 int link = parms->link; 376 struct ip_tunnel *t; 377 struct ip_tunnel __rcu **tp; 378 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 379 380 for (tp = __ipgre_bucket(ign, parms); 381 (t = rtnl_dereference(*tp)) != NULL; 382 tp = &t->next) 383 if (local == t->parms.iph.saddr && 384 remote == t->parms.iph.daddr && 385 key == t->parms.i_key && 386 link == t->parms.link && 387 type == t->dev->type) 388 break; 389 390 return t; 391 } 392 393 static struct ip_tunnel *ipgre_tunnel_locate(struct net *net, 394 struct ip_tunnel_parm *parms, int create) 395 { 396 struct ip_tunnel *t, *nt; 397 struct net_device *dev; 398 char name[IFNAMSIZ]; 399 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 400 401 t = ipgre_tunnel_find(net, parms, ARPHRD_IPGRE); 402 if (t || !create) 403 return t; 404 405 if (parms->name[0]) 406 strlcpy(name, parms->name, IFNAMSIZ); 407 else 408 strcpy(name, "gre%d"); 409 410 dev = alloc_netdev(sizeof(*t), name, ipgre_tunnel_setup); 411 if (!dev) 412 return NULL; 413 414 dev_net_set(dev, net); 415 416 nt = netdev_priv(dev); 417 nt->parms = *parms; 418 dev->rtnl_link_ops = &ipgre_link_ops; 419 420 dev->mtu = ipgre_tunnel_bind_dev(dev); 421 422 if (register_netdevice(dev) < 0) 423 goto failed_free; 424 425 dev_hold(dev); 426 ipgre_tunnel_link(ign, nt); 427 return nt; 428 429 failed_free: 430 free_netdev(dev); 431 return NULL; 432 } 433 434 static void ipgre_tunnel_uninit(struct net_device *dev) 435 { 436 struct net *net = dev_net(dev); 437 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 438 439 ipgre_tunnel_unlink(ign, netdev_priv(dev)); 440 dev_put(dev); 441 } 442 443 444 static void ipgre_err(struct sk_buff *skb, u32 info) 445 { 446 447 /* All the routers (except for Linux) return only 448 8 bytes of packet payload. It means, that precise relaying of 449 ICMP in the real Internet is absolutely infeasible. 450 451 Moreover, Cisco "wise men" put GRE key to the third word 452 in GRE header. It makes impossible maintaining even soft state for keyed 453 GRE tunnels with enabled checksum. Tell them "thank you". 454 455 Well, I wonder, rfc1812 was written by Cisco employee, 456 what the hell these idiots break standrads established 457 by themself??? 458 */ 459 460 const struct iphdr *iph = (const struct iphdr *)skb->data; 461 __be16 *p = (__be16*)(skb->data+(iph->ihl<<2)); 462 int grehlen = (iph->ihl<<2) + 4; 463 const int type = icmp_hdr(skb)->type; 464 const int code = icmp_hdr(skb)->code; 465 struct ip_tunnel *t; 466 __be16 flags; 467 468 flags = p[0]; 469 if (flags&(GRE_CSUM|GRE_KEY|GRE_SEQ|GRE_ROUTING|GRE_VERSION)) { 470 if (flags&(GRE_VERSION|GRE_ROUTING)) 471 return; 472 if (flags&GRE_KEY) { 473 grehlen += 4; 474 if (flags&GRE_CSUM) 475 grehlen += 4; 476 } 477 } 478 479 /* If only 8 bytes returned, keyed message will be dropped here */ 480 if (skb_headlen(skb) < grehlen) 481 return; 482 483 switch (type) { 484 default: 485 case ICMP_PARAMETERPROB: 486 return; 487 488 case ICMP_DEST_UNREACH: 489 switch (code) { 490 case ICMP_SR_FAILED: 491 case ICMP_PORT_UNREACH: 492 /* Impossible event. */ 493 return; 494 case ICMP_FRAG_NEEDED: 495 /* Soft state for pmtu is maintained by IP core. */ 496 return; 497 default: 498 /* All others are translated to HOST_UNREACH. 499 rfc2003 contains "deep thoughts" about NET_UNREACH, 500 I believe they are just ether pollution. --ANK 501 */ 502 break; 503 } 504 break; 505 case ICMP_TIME_EXCEEDED: 506 if (code != ICMP_EXC_TTL) 507 return; 508 break; 509 } 510 511 rcu_read_lock(); 512 t = ipgre_tunnel_lookup(skb->dev, iph->daddr, iph->saddr, 513 flags & GRE_KEY ? 514 *(((__be32 *)p) + (grehlen / 4) - 1) : 0, 515 p[1]); 516 if (t == NULL || t->parms.iph.daddr == 0 || 517 ipv4_is_multicast(t->parms.iph.daddr)) 518 goto out; 519 520 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) 521 goto out; 522 523 if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO)) 524 t->err_count++; 525 else 526 t->err_count = 1; 527 t->err_time = jiffies; 528 out: 529 rcu_read_unlock(); 530 } 531 532 static inline void ipgre_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb) 533 { 534 if (INET_ECN_is_ce(iph->tos)) { 535 if (skb->protocol == htons(ETH_P_IP)) { 536 IP_ECN_set_ce(ip_hdr(skb)); 537 } else if (skb->protocol == htons(ETH_P_IPV6)) { 538 IP6_ECN_set_ce(ipv6_hdr(skb)); 539 } 540 } 541 } 542 543 static inline u8 544 ipgre_ecn_encapsulate(u8 tos, const struct iphdr *old_iph, struct sk_buff *skb) 545 { 546 u8 inner = 0; 547 if (skb->protocol == htons(ETH_P_IP)) 548 inner = old_iph->tos; 549 else if (skb->protocol == htons(ETH_P_IPV6)) 550 inner = ipv6_get_dsfield((const struct ipv6hdr *)old_iph); 551 return INET_ECN_encapsulate(tos, inner); 552 } 553 554 static int ipgre_rcv(struct sk_buff *skb) 555 { 556 const struct iphdr *iph; 557 u8 *h; 558 __be16 flags; 559 __sum16 csum = 0; 560 __be32 key = 0; 561 u32 seqno = 0; 562 struct ip_tunnel *tunnel; 563 int offset = 4; 564 __be16 gre_proto; 565 566 if (!pskb_may_pull(skb, 16)) 567 goto drop_nolock; 568 569 iph = ip_hdr(skb); 570 h = skb->data; 571 flags = *(__be16*)h; 572 573 if (flags&(GRE_CSUM|GRE_KEY|GRE_ROUTING|GRE_SEQ|GRE_VERSION)) { 574 /* - Version must be 0. 575 - We do not support routing headers. 576 */ 577 if (flags&(GRE_VERSION|GRE_ROUTING)) 578 goto drop_nolock; 579 580 if (flags&GRE_CSUM) { 581 switch (skb->ip_summed) { 582 case CHECKSUM_COMPLETE: 583 csum = csum_fold(skb->csum); 584 if (!csum) 585 break; 586 /* fall through */ 587 case CHECKSUM_NONE: 588 skb->csum = 0; 589 csum = __skb_checksum_complete(skb); 590 skb->ip_summed = CHECKSUM_COMPLETE; 591 } 592 offset += 4; 593 } 594 if (flags&GRE_KEY) { 595 key = *(__be32*)(h + offset); 596 offset += 4; 597 } 598 if (flags&GRE_SEQ) { 599 seqno = ntohl(*(__be32*)(h + offset)); 600 offset += 4; 601 } 602 } 603 604 gre_proto = *(__be16 *)(h + 2); 605 606 rcu_read_lock(); 607 if ((tunnel = ipgre_tunnel_lookup(skb->dev, 608 iph->saddr, iph->daddr, key, 609 gre_proto))) { 610 struct pcpu_tstats *tstats; 611 612 secpath_reset(skb); 613 614 skb->protocol = gre_proto; 615 /* WCCP version 1 and 2 protocol decoding. 616 * - Change protocol to IP 617 * - When dealing with WCCPv2, Skip extra 4 bytes in GRE header 618 */ 619 if (flags == 0 && gre_proto == htons(ETH_P_WCCP)) { 620 skb->protocol = htons(ETH_P_IP); 621 if ((*(h + offset) & 0xF0) != 0x40) 622 offset += 4; 623 } 624 625 skb->mac_header = skb->network_header; 626 __pskb_pull(skb, offset); 627 skb_postpull_rcsum(skb, skb_transport_header(skb), offset); 628 skb->pkt_type = PACKET_HOST; 629 #ifdef CONFIG_NET_IPGRE_BROADCAST 630 if (ipv4_is_multicast(iph->daddr)) { 631 /* Looped back packet, drop it! */ 632 if (rt_is_output_route(skb_rtable(skb))) 633 goto drop; 634 tunnel->dev->stats.multicast++; 635 skb->pkt_type = PACKET_BROADCAST; 636 } 637 #endif 638 639 if (((flags&GRE_CSUM) && csum) || 640 (!(flags&GRE_CSUM) && tunnel->parms.i_flags&GRE_CSUM)) { 641 tunnel->dev->stats.rx_crc_errors++; 642 tunnel->dev->stats.rx_errors++; 643 goto drop; 644 } 645 if (tunnel->parms.i_flags&GRE_SEQ) { 646 if (!(flags&GRE_SEQ) || 647 (tunnel->i_seqno && (s32)(seqno - tunnel->i_seqno) < 0)) { 648 tunnel->dev->stats.rx_fifo_errors++; 649 tunnel->dev->stats.rx_errors++; 650 goto drop; 651 } 652 tunnel->i_seqno = seqno + 1; 653 } 654 655 /* Warning: All skb pointers will be invalidated! */ 656 if (tunnel->dev->type == ARPHRD_ETHER) { 657 if (!pskb_may_pull(skb, ETH_HLEN)) { 658 tunnel->dev->stats.rx_length_errors++; 659 tunnel->dev->stats.rx_errors++; 660 goto drop; 661 } 662 663 iph = ip_hdr(skb); 664 skb->protocol = eth_type_trans(skb, tunnel->dev); 665 skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); 666 } 667 668 tstats = this_cpu_ptr(tunnel->dev->tstats); 669 tstats->rx_packets++; 670 tstats->rx_bytes += skb->len; 671 672 __skb_tunnel_rx(skb, tunnel->dev); 673 674 skb_reset_network_header(skb); 675 ipgre_ecn_decapsulate(iph, skb); 676 677 netif_rx(skb); 678 679 rcu_read_unlock(); 680 return 0; 681 } 682 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); 683 684 drop: 685 rcu_read_unlock(); 686 drop_nolock: 687 kfree_skb(skb); 688 return 0; 689 } 690 691 static netdev_tx_t ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 692 { 693 struct ip_tunnel *tunnel = netdev_priv(dev); 694 struct pcpu_tstats *tstats; 695 const struct iphdr *old_iph = ip_hdr(skb); 696 const struct iphdr *tiph; 697 struct flowi4 fl4; 698 u8 tos; 699 __be16 df; 700 struct rtable *rt; /* Route to the other host */ 701 struct net_device *tdev; /* Device to other host */ 702 struct iphdr *iph; /* Our new IP header */ 703 unsigned int max_headroom; /* The extra header space needed */ 704 int gre_hlen; 705 __be32 dst; 706 int mtu; 707 708 if (dev->type == ARPHRD_ETHER) 709 IPCB(skb)->flags = 0; 710 711 if (dev->header_ops && dev->type == ARPHRD_IPGRE) { 712 gre_hlen = 0; 713 tiph = (const struct iphdr *)skb->data; 714 } else { 715 gre_hlen = tunnel->hlen; 716 tiph = &tunnel->parms.iph; 717 } 718 719 if ((dst = tiph->daddr) == 0) { 720 /* NBMA tunnel */ 721 722 if (skb_dst(skb) == NULL) { 723 dev->stats.tx_fifo_errors++; 724 goto tx_error; 725 } 726 727 if (skb->protocol == htons(ETH_P_IP)) { 728 rt = skb_rtable(skb); 729 if ((dst = rt->rt_gateway) == 0) 730 goto tx_error_icmp; 731 } 732 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 733 else if (skb->protocol == htons(ETH_P_IPV6)) { 734 struct neighbour *neigh = dst_get_neighbour(skb_dst(skb)); 735 const struct in6_addr *addr6; 736 int addr_type; 737 738 if (neigh == NULL) 739 goto tx_error; 740 741 addr6 = (const struct in6_addr *)&neigh->primary_key; 742 addr_type = ipv6_addr_type(addr6); 743 744 if (addr_type == IPV6_ADDR_ANY) { 745 addr6 = &ipv6_hdr(skb)->daddr; 746 addr_type = ipv6_addr_type(addr6); 747 } 748 749 if ((addr_type & IPV6_ADDR_COMPATv4) == 0) 750 goto tx_error_icmp; 751 752 dst = addr6->s6_addr32[3]; 753 } 754 #endif 755 else 756 goto tx_error; 757 } 758 759 tos = tiph->tos; 760 if (tos == 1) { 761 tos = 0; 762 if (skb->protocol == htons(ETH_P_IP)) 763 tos = old_iph->tos; 764 else if (skb->protocol == htons(ETH_P_IPV6)) 765 tos = ipv6_get_dsfield((const struct ipv6hdr *)old_iph); 766 } 767 768 rt = ip_route_output_gre(dev_net(dev), &fl4, dst, tiph->saddr, 769 tunnel->parms.o_key, RT_TOS(tos), 770 tunnel->parms.link); 771 if (IS_ERR(rt)) { 772 dev->stats.tx_carrier_errors++; 773 goto tx_error; 774 } 775 tdev = rt->dst.dev; 776 777 if (tdev == dev) { 778 ip_rt_put(rt); 779 dev->stats.collisions++; 780 goto tx_error; 781 } 782 783 df = tiph->frag_off; 784 if (df) 785 mtu = dst_mtu(&rt->dst) - dev->hard_header_len - tunnel->hlen; 786 else 787 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu; 788 789 if (skb_dst(skb)) 790 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu); 791 792 if (skb->protocol == htons(ETH_P_IP)) { 793 df |= (old_iph->frag_off&htons(IP_DF)); 794 795 if ((old_iph->frag_off&htons(IP_DF)) && 796 mtu < ntohs(old_iph->tot_len)) { 797 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu)); 798 ip_rt_put(rt); 799 goto tx_error; 800 } 801 } 802 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 803 else if (skb->protocol == htons(ETH_P_IPV6)) { 804 struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb); 805 806 if (rt6 && mtu < dst_mtu(skb_dst(skb)) && mtu >= IPV6_MIN_MTU) { 807 if ((tunnel->parms.iph.daddr && 808 !ipv4_is_multicast(tunnel->parms.iph.daddr)) || 809 rt6->rt6i_dst.plen == 128) { 810 rt6->rt6i_flags |= RTF_MODIFIED; 811 dst_metric_set(skb_dst(skb), RTAX_MTU, mtu); 812 } 813 } 814 815 if (mtu >= IPV6_MIN_MTU && mtu < skb->len - tunnel->hlen + gre_hlen) { 816 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu); 817 ip_rt_put(rt); 818 goto tx_error; 819 } 820 } 821 #endif 822 823 if (tunnel->err_count > 0) { 824 if (time_before(jiffies, 825 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) { 826 tunnel->err_count--; 827 828 dst_link_failure(skb); 829 } else 830 tunnel->err_count = 0; 831 } 832 833 max_headroom = LL_RESERVED_SPACE(tdev) + gre_hlen + rt->dst.header_len; 834 835 if (skb_headroom(skb) < max_headroom || skb_shared(skb)|| 836 (skb_cloned(skb) && !skb_clone_writable(skb, 0))) { 837 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 838 if (!new_skb) { 839 ip_rt_put(rt); 840 dev->stats.tx_dropped++; 841 dev_kfree_skb(skb); 842 return NETDEV_TX_OK; 843 } 844 if (skb->sk) 845 skb_set_owner_w(new_skb, skb->sk); 846 dev_kfree_skb(skb); 847 skb = new_skb; 848 old_iph = ip_hdr(skb); 849 } 850 851 skb_reset_transport_header(skb); 852 skb_push(skb, gre_hlen); 853 skb_reset_network_header(skb); 854 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 855 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 856 IPSKB_REROUTED); 857 skb_dst_drop(skb); 858 skb_dst_set(skb, &rt->dst); 859 860 /* 861 * Push down and install the IPIP header. 862 */ 863 864 iph = ip_hdr(skb); 865 iph->version = 4; 866 iph->ihl = sizeof(struct iphdr) >> 2; 867 iph->frag_off = df; 868 iph->protocol = IPPROTO_GRE; 869 iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb); 870 iph->daddr = fl4.daddr; 871 iph->saddr = fl4.saddr; 872 873 if ((iph->ttl = tiph->ttl) == 0) { 874 if (skb->protocol == htons(ETH_P_IP)) 875 iph->ttl = old_iph->ttl; 876 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 877 else if (skb->protocol == htons(ETH_P_IPV6)) 878 iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit; 879 #endif 880 else 881 iph->ttl = ip4_dst_hoplimit(&rt->dst); 882 } 883 884 ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags; 885 ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ? 886 htons(ETH_P_TEB) : skb->protocol; 887 888 if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) { 889 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4); 890 891 if (tunnel->parms.o_flags&GRE_SEQ) { 892 ++tunnel->o_seqno; 893 *ptr = htonl(tunnel->o_seqno); 894 ptr--; 895 } 896 if (tunnel->parms.o_flags&GRE_KEY) { 897 *ptr = tunnel->parms.o_key; 898 ptr--; 899 } 900 if (tunnel->parms.o_flags&GRE_CSUM) { 901 *ptr = 0; 902 *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr)); 903 } 904 } 905 906 nf_reset(skb); 907 tstats = this_cpu_ptr(dev->tstats); 908 __IPTUNNEL_XMIT(tstats, &dev->stats); 909 return NETDEV_TX_OK; 910 911 tx_error_icmp: 912 dst_link_failure(skb); 913 914 tx_error: 915 dev->stats.tx_errors++; 916 dev_kfree_skb(skb); 917 return NETDEV_TX_OK; 918 } 919 920 static int ipgre_tunnel_bind_dev(struct net_device *dev) 921 { 922 struct net_device *tdev = NULL; 923 struct ip_tunnel *tunnel; 924 const struct iphdr *iph; 925 int hlen = LL_MAX_HEADER; 926 int mtu = ETH_DATA_LEN; 927 int addend = sizeof(struct iphdr) + 4; 928 929 tunnel = netdev_priv(dev); 930 iph = &tunnel->parms.iph; 931 932 /* Guess output device to choose reasonable mtu and needed_headroom */ 933 934 if (iph->daddr) { 935 struct flowi4 fl4; 936 struct rtable *rt; 937 938 rt = ip_route_output_gre(dev_net(dev), &fl4, 939 iph->daddr, iph->saddr, 940 tunnel->parms.o_key, 941 RT_TOS(iph->tos), 942 tunnel->parms.link); 943 if (!IS_ERR(rt)) { 944 tdev = rt->dst.dev; 945 ip_rt_put(rt); 946 } 947 948 if (dev->type != ARPHRD_ETHER) 949 dev->flags |= IFF_POINTOPOINT; 950 } 951 952 if (!tdev && tunnel->parms.link) 953 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link); 954 955 if (tdev) { 956 hlen = tdev->hard_header_len + tdev->needed_headroom; 957 mtu = tdev->mtu; 958 } 959 dev->iflink = tunnel->parms.link; 960 961 /* Precalculate GRE options length */ 962 if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) { 963 if (tunnel->parms.o_flags&GRE_CSUM) 964 addend += 4; 965 if (tunnel->parms.o_flags&GRE_KEY) 966 addend += 4; 967 if (tunnel->parms.o_flags&GRE_SEQ) 968 addend += 4; 969 } 970 dev->needed_headroom = addend + hlen; 971 mtu -= dev->hard_header_len + addend; 972 973 if (mtu < 68) 974 mtu = 68; 975 976 tunnel->hlen = addend; 977 978 return mtu; 979 } 980 981 static int 982 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) 983 { 984 int err = 0; 985 struct ip_tunnel_parm p; 986 struct ip_tunnel *t; 987 struct net *net = dev_net(dev); 988 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 989 990 switch (cmd) { 991 case SIOCGETTUNNEL: 992 t = NULL; 993 if (dev == ign->fb_tunnel_dev) { 994 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) { 995 err = -EFAULT; 996 break; 997 } 998 t = ipgre_tunnel_locate(net, &p, 0); 999 } 1000 if (t == NULL) 1001 t = netdev_priv(dev); 1002 memcpy(&p, &t->parms, sizeof(p)); 1003 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 1004 err = -EFAULT; 1005 break; 1006 1007 case SIOCADDTUNNEL: 1008 case SIOCCHGTUNNEL: 1009 err = -EPERM; 1010 if (!capable(CAP_NET_ADMIN)) 1011 goto done; 1012 1013 err = -EFAULT; 1014 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 1015 goto done; 1016 1017 err = -EINVAL; 1018 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE || 1019 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) || 1020 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING))) 1021 goto done; 1022 if (p.iph.ttl) 1023 p.iph.frag_off |= htons(IP_DF); 1024 1025 if (!(p.i_flags&GRE_KEY)) 1026 p.i_key = 0; 1027 if (!(p.o_flags&GRE_KEY)) 1028 p.o_key = 0; 1029 1030 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL); 1031 1032 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) { 1033 if (t != NULL) { 1034 if (t->dev != dev) { 1035 err = -EEXIST; 1036 break; 1037 } 1038 } else { 1039 unsigned int nflags = 0; 1040 1041 t = netdev_priv(dev); 1042 1043 if (ipv4_is_multicast(p.iph.daddr)) 1044 nflags = IFF_BROADCAST; 1045 else if (p.iph.daddr) 1046 nflags = IFF_POINTOPOINT; 1047 1048 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) { 1049 err = -EINVAL; 1050 break; 1051 } 1052 ipgre_tunnel_unlink(ign, t); 1053 synchronize_net(); 1054 t->parms.iph.saddr = p.iph.saddr; 1055 t->parms.iph.daddr = p.iph.daddr; 1056 t->parms.i_key = p.i_key; 1057 t->parms.o_key = p.o_key; 1058 memcpy(dev->dev_addr, &p.iph.saddr, 4); 1059 memcpy(dev->broadcast, &p.iph.daddr, 4); 1060 ipgre_tunnel_link(ign, t); 1061 netdev_state_change(dev); 1062 } 1063 } 1064 1065 if (t) { 1066 err = 0; 1067 if (cmd == SIOCCHGTUNNEL) { 1068 t->parms.iph.ttl = p.iph.ttl; 1069 t->parms.iph.tos = p.iph.tos; 1070 t->parms.iph.frag_off = p.iph.frag_off; 1071 if (t->parms.link != p.link) { 1072 t->parms.link = p.link; 1073 dev->mtu = ipgre_tunnel_bind_dev(dev); 1074 netdev_state_change(dev); 1075 } 1076 } 1077 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) 1078 err = -EFAULT; 1079 } else 1080 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT); 1081 break; 1082 1083 case SIOCDELTUNNEL: 1084 err = -EPERM; 1085 if (!capable(CAP_NET_ADMIN)) 1086 goto done; 1087 1088 if (dev == ign->fb_tunnel_dev) { 1089 err = -EFAULT; 1090 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 1091 goto done; 1092 err = -ENOENT; 1093 if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL) 1094 goto done; 1095 err = -EPERM; 1096 if (t == netdev_priv(ign->fb_tunnel_dev)) 1097 goto done; 1098 dev = t->dev; 1099 } 1100 unregister_netdevice(dev); 1101 err = 0; 1102 break; 1103 1104 default: 1105 err = -EINVAL; 1106 } 1107 1108 done: 1109 return err; 1110 } 1111 1112 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu) 1113 { 1114 struct ip_tunnel *tunnel = netdev_priv(dev); 1115 if (new_mtu < 68 || 1116 new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen) 1117 return -EINVAL; 1118 dev->mtu = new_mtu; 1119 return 0; 1120 } 1121 1122 /* Nice toy. Unfortunately, useless in real life :-) 1123 It allows to construct virtual multiprotocol broadcast "LAN" 1124 over the Internet, provided multicast routing is tuned. 1125 1126 1127 I have no idea was this bicycle invented before me, 1128 so that I had to set ARPHRD_IPGRE to a random value. 1129 I have an impression, that Cisco could make something similar, 1130 but this feature is apparently missing in IOS<=11.2(8). 1131 1132 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks 1133 with broadcast 224.66.66.66. If you have access to mbone, play with me :-) 1134 1135 ping -t 255 224.66.66.66 1136 1137 If nobody answers, mbone does not work. 1138 1139 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255 1140 ip addr add 10.66.66.<somewhat>/24 dev Universe 1141 ifconfig Universe up 1142 ifconfig Universe add fe80::<Your_real_addr>/10 1143 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96 1144 ftp 10.66.66.66 1145 ... 1146 ftp fec0:6666:6666::193.233.7.65 1147 ... 1148 1149 */ 1150 1151 static int ipgre_header(struct sk_buff *skb, struct net_device *dev, 1152 unsigned short type, 1153 const void *daddr, const void *saddr, unsigned int len) 1154 { 1155 struct ip_tunnel *t = netdev_priv(dev); 1156 struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen); 1157 __be16 *p = (__be16*)(iph+1); 1158 1159 memcpy(iph, &t->parms.iph, sizeof(struct iphdr)); 1160 p[0] = t->parms.o_flags; 1161 p[1] = htons(type); 1162 1163 /* 1164 * Set the source hardware address. 1165 */ 1166 1167 if (saddr) 1168 memcpy(&iph->saddr, saddr, 4); 1169 if (daddr) 1170 memcpy(&iph->daddr, daddr, 4); 1171 if (iph->daddr) 1172 return t->hlen; 1173 1174 return -t->hlen; 1175 } 1176 1177 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr) 1178 { 1179 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb); 1180 memcpy(haddr, &iph->saddr, 4); 1181 return 4; 1182 } 1183 1184 static const struct header_ops ipgre_header_ops = { 1185 .create = ipgre_header, 1186 .parse = ipgre_header_parse, 1187 }; 1188 1189 #ifdef CONFIG_NET_IPGRE_BROADCAST 1190 static int ipgre_open(struct net_device *dev) 1191 { 1192 struct ip_tunnel *t = netdev_priv(dev); 1193 1194 if (ipv4_is_multicast(t->parms.iph.daddr)) { 1195 struct flowi4 fl4; 1196 struct rtable *rt; 1197 1198 rt = ip_route_output_gre(dev_net(dev), &fl4, 1199 t->parms.iph.daddr, 1200 t->parms.iph.saddr, 1201 t->parms.o_key, 1202 RT_TOS(t->parms.iph.tos), 1203 t->parms.link); 1204 if (IS_ERR(rt)) 1205 return -EADDRNOTAVAIL; 1206 dev = rt->dst.dev; 1207 ip_rt_put(rt); 1208 if (__in_dev_get_rtnl(dev) == NULL) 1209 return -EADDRNOTAVAIL; 1210 t->mlink = dev->ifindex; 1211 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr); 1212 } 1213 return 0; 1214 } 1215 1216 static int ipgre_close(struct net_device *dev) 1217 { 1218 struct ip_tunnel *t = netdev_priv(dev); 1219 1220 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) { 1221 struct in_device *in_dev; 1222 in_dev = inetdev_by_index(dev_net(dev), t->mlink); 1223 if (in_dev) 1224 ip_mc_dec_group(in_dev, t->parms.iph.daddr); 1225 } 1226 return 0; 1227 } 1228 1229 #endif 1230 1231 static const struct net_device_ops ipgre_netdev_ops = { 1232 .ndo_init = ipgre_tunnel_init, 1233 .ndo_uninit = ipgre_tunnel_uninit, 1234 #ifdef CONFIG_NET_IPGRE_BROADCAST 1235 .ndo_open = ipgre_open, 1236 .ndo_stop = ipgre_close, 1237 #endif 1238 .ndo_start_xmit = ipgre_tunnel_xmit, 1239 .ndo_do_ioctl = ipgre_tunnel_ioctl, 1240 .ndo_change_mtu = ipgre_tunnel_change_mtu, 1241 .ndo_get_stats = ipgre_get_stats, 1242 }; 1243 1244 static void ipgre_dev_free(struct net_device *dev) 1245 { 1246 free_percpu(dev->tstats); 1247 free_netdev(dev); 1248 } 1249 1250 static void ipgre_tunnel_setup(struct net_device *dev) 1251 { 1252 dev->netdev_ops = &ipgre_netdev_ops; 1253 dev->destructor = ipgre_dev_free; 1254 1255 dev->type = ARPHRD_IPGRE; 1256 dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4; 1257 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4; 1258 dev->flags = IFF_NOARP; 1259 dev->iflink = 0; 1260 dev->addr_len = 4; 1261 dev->features |= NETIF_F_NETNS_LOCAL; 1262 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; 1263 } 1264 1265 static int ipgre_tunnel_init(struct net_device *dev) 1266 { 1267 struct ip_tunnel *tunnel; 1268 struct iphdr *iph; 1269 1270 tunnel = netdev_priv(dev); 1271 iph = &tunnel->parms.iph; 1272 1273 tunnel->dev = dev; 1274 strcpy(tunnel->parms.name, dev->name); 1275 1276 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); 1277 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); 1278 1279 if (iph->daddr) { 1280 #ifdef CONFIG_NET_IPGRE_BROADCAST 1281 if (ipv4_is_multicast(iph->daddr)) { 1282 if (!iph->saddr) 1283 return -EINVAL; 1284 dev->flags = IFF_BROADCAST; 1285 dev->header_ops = &ipgre_header_ops; 1286 } 1287 #endif 1288 } else 1289 dev->header_ops = &ipgre_header_ops; 1290 1291 dev->tstats = alloc_percpu(struct pcpu_tstats); 1292 if (!dev->tstats) 1293 return -ENOMEM; 1294 1295 return 0; 1296 } 1297 1298 static void ipgre_fb_tunnel_init(struct net_device *dev) 1299 { 1300 struct ip_tunnel *tunnel = netdev_priv(dev); 1301 struct iphdr *iph = &tunnel->parms.iph; 1302 1303 tunnel->dev = dev; 1304 strcpy(tunnel->parms.name, dev->name); 1305 1306 iph->version = 4; 1307 iph->protocol = IPPROTO_GRE; 1308 iph->ihl = 5; 1309 tunnel->hlen = sizeof(struct iphdr) + 4; 1310 1311 dev_hold(dev); 1312 } 1313 1314 1315 static const struct gre_protocol ipgre_protocol = { 1316 .handler = ipgre_rcv, 1317 .err_handler = ipgre_err, 1318 }; 1319 1320 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head) 1321 { 1322 int prio; 1323 1324 for (prio = 0; prio < 4; prio++) { 1325 int h; 1326 for (h = 0; h < HASH_SIZE; h++) { 1327 struct ip_tunnel *t; 1328 1329 t = rtnl_dereference(ign->tunnels[prio][h]); 1330 1331 while (t != NULL) { 1332 unregister_netdevice_queue(t->dev, head); 1333 t = rtnl_dereference(t->next); 1334 } 1335 } 1336 } 1337 } 1338 1339 static int __net_init ipgre_init_net(struct net *net) 1340 { 1341 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1342 int err; 1343 1344 ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0", 1345 ipgre_tunnel_setup); 1346 if (!ign->fb_tunnel_dev) { 1347 err = -ENOMEM; 1348 goto err_alloc_dev; 1349 } 1350 dev_net_set(ign->fb_tunnel_dev, net); 1351 1352 ipgre_fb_tunnel_init(ign->fb_tunnel_dev); 1353 ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops; 1354 1355 if ((err = register_netdev(ign->fb_tunnel_dev))) 1356 goto err_reg_dev; 1357 1358 rcu_assign_pointer(ign->tunnels_wc[0], 1359 netdev_priv(ign->fb_tunnel_dev)); 1360 return 0; 1361 1362 err_reg_dev: 1363 ipgre_dev_free(ign->fb_tunnel_dev); 1364 err_alloc_dev: 1365 return err; 1366 } 1367 1368 static void __net_exit ipgre_exit_net(struct net *net) 1369 { 1370 struct ipgre_net *ign; 1371 LIST_HEAD(list); 1372 1373 ign = net_generic(net, ipgre_net_id); 1374 rtnl_lock(); 1375 ipgre_destroy_tunnels(ign, &list); 1376 unregister_netdevice_many(&list); 1377 rtnl_unlock(); 1378 } 1379 1380 static struct pernet_operations ipgre_net_ops = { 1381 .init = ipgre_init_net, 1382 .exit = ipgre_exit_net, 1383 .id = &ipgre_net_id, 1384 .size = sizeof(struct ipgre_net), 1385 }; 1386 1387 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) 1388 { 1389 __be16 flags; 1390 1391 if (!data) 1392 return 0; 1393 1394 flags = 0; 1395 if (data[IFLA_GRE_IFLAGS]) 1396 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); 1397 if (data[IFLA_GRE_OFLAGS]) 1398 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); 1399 if (flags & (GRE_VERSION|GRE_ROUTING)) 1400 return -EINVAL; 1401 1402 return 0; 1403 } 1404 1405 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[]) 1406 { 1407 __be32 daddr; 1408 1409 if (tb[IFLA_ADDRESS]) { 1410 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 1411 return -EINVAL; 1412 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 1413 return -EADDRNOTAVAIL; 1414 } 1415 1416 if (!data) 1417 goto out; 1418 1419 if (data[IFLA_GRE_REMOTE]) { 1420 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4); 1421 if (!daddr) 1422 return -EINVAL; 1423 } 1424 1425 out: 1426 return ipgre_tunnel_validate(tb, data); 1427 } 1428 1429 static void ipgre_netlink_parms(struct nlattr *data[], 1430 struct ip_tunnel_parm *parms) 1431 { 1432 memset(parms, 0, sizeof(*parms)); 1433 1434 parms->iph.protocol = IPPROTO_GRE; 1435 1436 if (!data) 1437 return; 1438 1439 if (data[IFLA_GRE_LINK]) 1440 parms->link = nla_get_u32(data[IFLA_GRE_LINK]); 1441 1442 if (data[IFLA_GRE_IFLAGS]) 1443 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]); 1444 1445 if (data[IFLA_GRE_OFLAGS]) 1446 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]); 1447 1448 if (data[IFLA_GRE_IKEY]) 1449 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]); 1450 1451 if (data[IFLA_GRE_OKEY]) 1452 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]); 1453 1454 if (data[IFLA_GRE_LOCAL]) 1455 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]); 1456 1457 if (data[IFLA_GRE_REMOTE]) 1458 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]); 1459 1460 if (data[IFLA_GRE_TTL]) 1461 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]); 1462 1463 if (data[IFLA_GRE_TOS]) 1464 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]); 1465 1466 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) 1467 parms->iph.frag_off = htons(IP_DF); 1468 } 1469 1470 static int ipgre_tap_init(struct net_device *dev) 1471 { 1472 struct ip_tunnel *tunnel; 1473 1474 tunnel = netdev_priv(dev); 1475 1476 tunnel->dev = dev; 1477 strcpy(tunnel->parms.name, dev->name); 1478 1479 ipgre_tunnel_bind_dev(dev); 1480 1481 dev->tstats = alloc_percpu(struct pcpu_tstats); 1482 if (!dev->tstats) 1483 return -ENOMEM; 1484 1485 return 0; 1486 } 1487 1488 static const struct net_device_ops ipgre_tap_netdev_ops = { 1489 .ndo_init = ipgre_tap_init, 1490 .ndo_uninit = ipgre_tunnel_uninit, 1491 .ndo_start_xmit = ipgre_tunnel_xmit, 1492 .ndo_set_mac_address = eth_mac_addr, 1493 .ndo_validate_addr = eth_validate_addr, 1494 .ndo_change_mtu = ipgre_tunnel_change_mtu, 1495 .ndo_get_stats = ipgre_get_stats, 1496 }; 1497 1498 static void ipgre_tap_setup(struct net_device *dev) 1499 { 1500 1501 ether_setup(dev); 1502 1503 dev->netdev_ops = &ipgre_tap_netdev_ops; 1504 dev->destructor = ipgre_dev_free; 1505 1506 dev->iflink = 0; 1507 dev->features |= NETIF_F_NETNS_LOCAL; 1508 } 1509 1510 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[], 1511 struct nlattr *data[]) 1512 { 1513 struct ip_tunnel *nt; 1514 struct net *net = dev_net(dev); 1515 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1516 int mtu; 1517 int err; 1518 1519 nt = netdev_priv(dev); 1520 ipgre_netlink_parms(data, &nt->parms); 1521 1522 if (ipgre_tunnel_find(net, &nt->parms, dev->type)) 1523 return -EEXIST; 1524 1525 if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS]) 1526 random_ether_addr(dev->dev_addr); 1527 1528 mtu = ipgre_tunnel_bind_dev(dev); 1529 if (!tb[IFLA_MTU]) 1530 dev->mtu = mtu; 1531 1532 /* Can use a lockless transmit, unless we generate output sequences */ 1533 if (!(nt->parms.o_flags & GRE_SEQ)) 1534 dev->features |= NETIF_F_LLTX; 1535 1536 err = register_netdevice(dev); 1537 if (err) 1538 goto out; 1539 1540 dev_hold(dev); 1541 ipgre_tunnel_link(ign, nt); 1542 1543 out: 1544 return err; 1545 } 1546 1547 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 1548 struct nlattr *data[]) 1549 { 1550 struct ip_tunnel *t, *nt; 1551 struct net *net = dev_net(dev); 1552 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1553 struct ip_tunnel_parm p; 1554 int mtu; 1555 1556 if (dev == ign->fb_tunnel_dev) 1557 return -EINVAL; 1558 1559 nt = netdev_priv(dev); 1560 ipgre_netlink_parms(data, &p); 1561 1562 t = ipgre_tunnel_locate(net, &p, 0); 1563 1564 if (t) { 1565 if (t->dev != dev) 1566 return -EEXIST; 1567 } else { 1568 t = nt; 1569 1570 if (dev->type != ARPHRD_ETHER) { 1571 unsigned int nflags = 0; 1572 1573 if (ipv4_is_multicast(p.iph.daddr)) 1574 nflags = IFF_BROADCAST; 1575 else if (p.iph.daddr) 1576 nflags = IFF_POINTOPOINT; 1577 1578 if ((dev->flags ^ nflags) & 1579 (IFF_POINTOPOINT | IFF_BROADCAST)) 1580 return -EINVAL; 1581 } 1582 1583 ipgre_tunnel_unlink(ign, t); 1584 t->parms.iph.saddr = p.iph.saddr; 1585 t->parms.iph.daddr = p.iph.daddr; 1586 t->parms.i_key = p.i_key; 1587 if (dev->type != ARPHRD_ETHER) { 1588 memcpy(dev->dev_addr, &p.iph.saddr, 4); 1589 memcpy(dev->broadcast, &p.iph.daddr, 4); 1590 } 1591 ipgre_tunnel_link(ign, t); 1592 netdev_state_change(dev); 1593 } 1594 1595 t->parms.o_key = p.o_key; 1596 t->parms.iph.ttl = p.iph.ttl; 1597 t->parms.iph.tos = p.iph.tos; 1598 t->parms.iph.frag_off = p.iph.frag_off; 1599 1600 if (t->parms.link != p.link) { 1601 t->parms.link = p.link; 1602 mtu = ipgre_tunnel_bind_dev(dev); 1603 if (!tb[IFLA_MTU]) 1604 dev->mtu = mtu; 1605 netdev_state_change(dev); 1606 } 1607 1608 return 0; 1609 } 1610 1611 static size_t ipgre_get_size(const struct net_device *dev) 1612 { 1613 return 1614 /* IFLA_GRE_LINK */ 1615 nla_total_size(4) + 1616 /* IFLA_GRE_IFLAGS */ 1617 nla_total_size(2) + 1618 /* IFLA_GRE_OFLAGS */ 1619 nla_total_size(2) + 1620 /* IFLA_GRE_IKEY */ 1621 nla_total_size(4) + 1622 /* IFLA_GRE_OKEY */ 1623 nla_total_size(4) + 1624 /* IFLA_GRE_LOCAL */ 1625 nla_total_size(4) + 1626 /* IFLA_GRE_REMOTE */ 1627 nla_total_size(4) + 1628 /* IFLA_GRE_TTL */ 1629 nla_total_size(1) + 1630 /* IFLA_GRE_TOS */ 1631 nla_total_size(1) + 1632 /* IFLA_GRE_PMTUDISC */ 1633 nla_total_size(1) + 1634 0; 1635 } 1636 1637 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev) 1638 { 1639 struct ip_tunnel *t = netdev_priv(dev); 1640 struct ip_tunnel_parm *p = &t->parms; 1641 1642 NLA_PUT_U32(skb, IFLA_GRE_LINK, p->link); 1643 NLA_PUT_BE16(skb, IFLA_GRE_IFLAGS, p->i_flags); 1644 NLA_PUT_BE16(skb, IFLA_GRE_OFLAGS, p->o_flags); 1645 NLA_PUT_BE32(skb, IFLA_GRE_IKEY, p->i_key); 1646 NLA_PUT_BE32(skb, IFLA_GRE_OKEY, p->o_key); 1647 NLA_PUT_BE32(skb, IFLA_GRE_LOCAL, p->iph.saddr); 1648 NLA_PUT_BE32(skb, IFLA_GRE_REMOTE, p->iph.daddr); 1649 NLA_PUT_U8(skb, IFLA_GRE_TTL, p->iph.ttl); 1650 NLA_PUT_U8(skb, IFLA_GRE_TOS, p->iph.tos); 1651 NLA_PUT_U8(skb, IFLA_GRE_PMTUDISC, !!(p->iph.frag_off & htons(IP_DF))); 1652 1653 return 0; 1654 1655 nla_put_failure: 1656 return -EMSGSIZE; 1657 } 1658 1659 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = { 1660 [IFLA_GRE_LINK] = { .type = NLA_U32 }, 1661 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 }, 1662 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 }, 1663 [IFLA_GRE_IKEY] = { .type = NLA_U32 }, 1664 [IFLA_GRE_OKEY] = { .type = NLA_U32 }, 1665 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 1666 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 1667 [IFLA_GRE_TTL] = { .type = NLA_U8 }, 1668 [IFLA_GRE_TOS] = { .type = NLA_U8 }, 1669 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 }, 1670 }; 1671 1672 static struct rtnl_link_ops ipgre_link_ops __read_mostly = { 1673 .kind = "gre", 1674 .maxtype = IFLA_GRE_MAX, 1675 .policy = ipgre_policy, 1676 .priv_size = sizeof(struct ip_tunnel), 1677 .setup = ipgre_tunnel_setup, 1678 .validate = ipgre_tunnel_validate, 1679 .newlink = ipgre_newlink, 1680 .changelink = ipgre_changelink, 1681 .get_size = ipgre_get_size, 1682 .fill_info = ipgre_fill_info, 1683 }; 1684 1685 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = { 1686 .kind = "gretap", 1687 .maxtype = IFLA_GRE_MAX, 1688 .policy = ipgre_policy, 1689 .priv_size = sizeof(struct ip_tunnel), 1690 .setup = ipgre_tap_setup, 1691 .validate = ipgre_tap_validate, 1692 .newlink = ipgre_newlink, 1693 .changelink = ipgre_changelink, 1694 .get_size = ipgre_get_size, 1695 .fill_info = ipgre_fill_info, 1696 }; 1697 1698 /* 1699 * And now the modules code and kernel interface. 1700 */ 1701 1702 static int __init ipgre_init(void) 1703 { 1704 int err; 1705 1706 printk(KERN_INFO "GRE over IPv4 tunneling driver\n"); 1707 1708 err = register_pernet_device(&ipgre_net_ops); 1709 if (err < 0) 1710 return err; 1711 1712 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO); 1713 if (err < 0) { 1714 printk(KERN_INFO "ipgre init: can't add protocol\n"); 1715 goto add_proto_failed; 1716 } 1717 1718 err = rtnl_link_register(&ipgre_link_ops); 1719 if (err < 0) 1720 goto rtnl_link_failed; 1721 1722 err = rtnl_link_register(&ipgre_tap_ops); 1723 if (err < 0) 1724 goto tap_ops_failed; 1725 1726 out: 1727 return err; 1728 1729 tap_ops_failed: 1730 rtnl_link_unregister(&ipgre_link_ops); 1731 rtnl_link_failed: 1732 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); 1733 add_proto_failed: 1734 unregister_pernet_device(&ipgre_net_ops); 1735 goto out; 1736 } 1737 1738 static void __exit ipgre_fini(void) 1739 { 1740 rtnl_link_unregister(&ipgre_tap_ops); 1741 rtnl_link_unregister(&ipgre_link_ops); 1742 if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) 1743 printk(KERN_INFO "ipgre close: can't remove protocol\n"); 1744 unregister_pernet_device(&ipgre_net_ops); 1745 } 1746 1747 module_init(ipgre_init); 1748 module_exit(ipgre_fini); 1749 MODULE_LICENSE("GPL"); 1750 MODULE_ALIAS_RTNL_LINK("gre"); 1751 MODULE_ALIAS_RTNL_LINK("gretap"); 1752 MODULE_ALIAS_NETDEV("gre0"); 1753