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 (max_headroom > dev->needed_headroom) 839 dev->needed_headroom = max_headroom; 840 if (!new_skb) { 841 ip_rt_put(rt); 842 dev->stats.tx_dropped++; 843 dev_kfree_skb(skb); 844 return NETDEV_TX_OK; 845 } 846 if (skb->sk) 847 skb_set_owner_w(new_skb, skb->sk); 848 dev_kfree_skb(skb); 849 skb = new_skb; 850 old_iph = ip_hdr(skb); 851 } 852 853 skb_reset_transport_header(skb); 854 skb_push(skb, gre_hlen); 855 skb_reset_network_header(skb); 856 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 857 IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED | 858 IPSKB_REROUTED); 859 skb_dst_drop(skb); 860 skb_dst_set(skb, &rt->dst); 861 862 /* 863 * Push down and install the IPIP header. 864 */ 865 866 iph = ip_hdr(skb); 867 iph->version = 4; 868 iph->ihl = sizeof(struct iphdr) >> 2; 869 iph->frag_off = df; 870 iph->protocol = IPPROTO_GRE; 871 iph->tos = ipgre_ecn_encapsulate(tos, old_iph, skb); 872 iph->daddr = fl4.daddr; 873 iph->saddr = fl4.saddr; 874 875 if ((iph->ttl = tiph->ttl) == 0) { 876 if (skb->protocol == htons(ETH_P_IP)) 877 iph->ttl = old_iph->ttl; 878 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 879 else if (skb->protocol == htons(ETH_P_IPV6)) 880 iph->ttl = ((const struct ipv6hdr *)old_iph)->hop_limit; 881 #endif 882 else 883 iph->ttl = ip4_dst_hoplimit(&rt->dst); 884 } 885 886 ((__be16 *)(iph + 1))[0] = tunnel->parms.o_flags; 887 ((__be16 *)(iph + 1))[1] = (dev->type == ARPHRD_ETHER) ? 888 htons(ETH_P_TEB) : skb->protocol; 889 890 if (tunnel->parms.o_flags&(GRE_KEY|GRE_CSUM|GRE_SEQ)) { 891 __be32 *ptr = (__be32*)(((u8*)iph) + tunnel->hlen - 4); 892 893 if (tunnel->parms.o_flags&GRE_SEQ) { 894 ++tunnel->o_seqno; 895 *ptr = htonl(tunnel->o_seqno); 896 ptr--; 897 } 898 if (tunnel->parms.o_flags&GRE_KEY) { 899 *ptr = tunnel->parms.o_key; 900 ptr--; 901 } 902 if (tunnel->parms.o_flags&GRE_CSUM) { 903 *ptr = 0; 904 *(__sum16*)ptr = ip_compute_csum((void*)(iph+1), skb->len - sizeof(struct iphdr)); 905 } 906 } 907 908 nf_reset(skb); 909 tstats = this_cpu_ptr(dev->tstats); 910 __IPTUNNEL_XMIT(tstats, &dev->stats); 911 return NETDEV_TX_OK; 912 913 tx_error_icmp: 914 dst_link_failure(skb); 915 916 tx_error: 917 dev->stats.tx_errors++; 918 dev_kfree_skb(skb); 919 return NETDEV_TX_OK; 920 } 921 922 static int ipgre_tunnel_bind_dev(struct net_device *dev) 923 { 924 struct net_device *tdev = NULL; 925 struct ip_tunnel *tunnel; 926 const struct iphdr *iph; 927 int hlen = LL_MAX_HEADER; 928 int mtu = ETH_DATA_LEN; 929 int addend = sizeof(struct iphdr) + 4; 930 931 tunnel = netdev_priv(dev); 932 iph = &tunnel->parms.iph; 933 934 /* Guess output device to choose reasonable mtu and needed_headroom */ 935 936 if (iph->daddr) { 937 struct flowi4 fl4; 938 struct rtable *rt; 939 940 rt = ip_route_output_gre(dev_net(dev), &fl4, 941 iph->daddr, iph->saddr, 942 tunnel->parms.o_key, 943 RT_TOS(iph->tos), 944 tunnel->parms.link); 945 if (!IS_ERR(rt)) { 946 tdev = rt->dst.dev; 947 ip_rt_put(rt); 948 } 949 950 if (dev->type != ARPHRD_ETHER) 951 dev->flags |= IFF_POINTOPOINT; 952 } 953 954 if (!tdev && tunnel->parms.link) 955 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link); 956 957 if (tdev) { 958 hlen = tdev->hard_header_len + tdev->needed_headroom; 959 mtu = tdev->mtu; 960 } 961 dev->iflink = tunnel->parms.link; 962 963 /* Precalculate GRE options length */ 964 if (tunnel->parms.o_flags&(GRE_CSUM|GRE_KEY|GRE_SEQ)) { 965 if (tunnel->parms.o_flags&GRE_CSUM) 966 addend += 4; 967 if (tunnel->parms.o_flags&GRE_KEY) 968 addend += 4; 969 if (tunnel->parms.o_flags&GRE_SEQ) 970 addend += 4; 971 } 972 dev->needed_headroom = addend + hlen; 973 mtu -= dev->hard_header_len + addend; 974 975 if (mtu < 68) 976 mtu = 68; 977 978 tunnel->hlen = addend; 979 980 return mtu; 981 } 982 983 static int 984 ipgre_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) 985 { 986 int err = 0; 987 struct ip_tunnel_parm p; 988 struct ip_tunnel *t; 989 struct net *net = dev_net(dev); 990 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 991 992 switch (cmd) { 993 case SIOCGETTUNNEL: 994 t = NULL; 995 if (dev == ign->fb_tunnel_dev) { 996 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) { 997 err = -EFAULT; 998 break; 999 } 1000 t = ipgre_tunnel_locate(net, &p, 0); 1001 } 1002 if (t == NULL) 1003 t = netdev_priv(dev); 1004 memcpy(&p, &t->parms, sizeof(p)); 1005 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 1006 err = -EFAULT; 1007 break; 1008 1009 case SIOCADDTUNNEL: 1010 case SIOCCHGTUNNEL: 1011 err = -EPERM; 1012 if (!capable(CAP_NET_ADMIN)) 1013 goto done; 1014 1015 err = -EFAULT; 1016 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 1017 goto done; 1018 1019 err = -EINVAL; 1020 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_GRE || 1021 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)) || 1022 ((p.i_flags|p.o_flags)&(GRE_VERSION|GRE_ROUTING))) 1023 goto done; 1024 if (p.iph.ttl) 1025 p.iph.frag_off |= htons(IP_DF); 1026 1027 if (!(p.i_flags&GRE_KEY)) 1028 p.i_key = 0; 1029 if (!(p.o_flags&GRE_KEY)) 1030 p.o_key = 0; 1031 1032 t = ipgre_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL); 1033 1034 if (dev != ign->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) { 1035 if (t != NULL) { 1036 if (t->dev != dev) { 1037 err = -EEXIST; 1038 break; 1039 } 1040 } else { 1041 unsigned int nflags = 0; 1042 1043 t = netdev_priv(dev); 1044 1045 if (ipv4_is_multicast(p.iph.daddr)) 1046 nflags = IFF_BROADCAST; 1047 else if (p.iph.daddr) 1048 nflags = IFF_POINTOPOINT; 1049 1050 if ((dev->flags^nflags)&(IFF_POINTOPOINT|IFF_BROADCAST)) { 1051 err = -EINVAL; 1052 break; 1053 } 1054 ipgre_tunnel_unlink(ign, t); 1055 synchronize_net(); 1056 t->parms.iph.saddr = p.iph.saddr; 1057 t->parms.iph.daddr = p.iph.daddr; 1058 t->parms.i_key = p.i_key; 1059 t->parms.o_key = p.o_key; 1060 memcpy(dev->dev_addr, &p.iph.saddr, 4); 1061 memcpy(dev->broadcast, &p.iph.daddr, 4); 1062 ipgre_tunnel_link(ign, t); 1063 netdev_state_change(dev); 1064 } 1065 } 1066 1067 if (t) { 1068 err = 0; 1069 if (cmd == SIOCCHGTUNNEL) { 1070 t->parms.iph.ttl = p.iph.ttl; 1071 t->parms.iph.tos = p.iph.tos; 1072 t->parms.iph.frag_off = p.iph.frag_off; 1073 if (t->parms.link != p.link) { 1074 t->parms.link = p.link; 1075 dev->mtu = ipgre_tunnel_bind_dev(dev); 1076 netdev_state_change(dev); 1077 } 1078 } 1079 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) 1080 err = -EFAULT; 1081 } else 1082 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT); 1083 break; 1084 1085 case SIOCDELTUNNEL: 1086 err = -EPERM; 1087 if (!capable(CAP_NET_ADMIN)) 1088 goto done; 1089 1090 if (dev == ign->fb_tunnel_dev) { 1091 err = -EFAULT; 1092 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 1093 goto done; 1094 err = -ENOENT; 1095 if ((t = ipgre_tunnel_locate(net, &p, 0)) == NULL) 1096 goto done; 1097 err = -EPERM; 1098 if (t == netdev_priv(ign->fb_tunnel_dev)) 1099 goto done; 1100 dev = t->dev; 1101 } 1102 unregister_netdevice(dev); 1103 err = 0; 1104 break; 1105 1106 default: 1107 err = -EINVAL; 1108 } 1109 1110 done: 1111 return err; 1112 } 1113 1114 static int ipgre_tunnel_change_mtu(struct net_device *dev, int new_mtu) 1115 { 1116 struct ip_tunnel *tunnel = netdev_priv(dev); 1117 if (new_mtu < 68 || 1118 new_mtu > 0xFFF8 - dev->hard_header_len - tunnel->hlen) 1119 return -EINVAL; 1120 dev->mtu = new_mtu; 1121 return 0; 1122 } 1123 1124 /* Nice toy. Unfortunately, useless in real life :-) 1125 It allows to construct virtual multiprotocol broadcast "LAN" 1126 over the Internet, provided multicast routing is tuned. 1127 1128 1129 I have no idea was this bicycle invented before me, 1130 so that I had to set ARPHRD_IPGRE to a random value. 1131 I have an impression, that Cisco could make something similar, 1132 but this feature is apparently missing in IOS<=11.2(8). 1133 1134 I set up 10.66.66/24 and fec0:6666:6666::0/96 as virtual networks 1135 with broadcast 224.66.66.66. If you have access to mbone, play with me :-) 1136 1137 ping -t 255 224.66.66.66 1138 1139 If nobody answers, mbone does not work. 1140 1141 ip tunnel add Universe mode gre remote 224.66.66.66 local <Your_real_addr> ttl 255 1142 ip addr add 10.66.66.<somewhat>/24 dev Universe 1143 ifconfig Universe up 1144 ifconfig Universe add fe80::<Your_real_addr>/10 1145 ifconfig Universe add fec0:6666:6666::<Your_real_addr>/96 1146 ftp 10.66.66.66 1147 ... 1148 ftp fec0:6666:6666::193.233.7.65 1149 ... 1150 1151 */ 1152 1153 static int ipgre_header(struct sk_buff *skb, struct net_device *dev, 1154 unsigned short type, 1155 const void *daddr, const void *saddr, unsigned int len) 1156 { 1157 struct ip_tunnel *t = netdev_priv(dev); 1158 struct iphdr *iph = (struct iphdr *)skb_push(skb, t->hlen); 1159 __be16 *p = (__be16*)(iph+1); 1160 1161 memcpy(iph, &t->parms.iph, sizeof(struct iphdr)); 1162 p[0] = t->parms.o_flags; 1163 p[1] = htons(type); 1164 1165 /* 1166 * Set the source hardware address. 1167 */ 1168 1169 if (saddr) 1170 memcpy(&iph->saddr, saddr, 4); 1171 if (daddr) 1172 memcpy(&iph->daddr, daddr, 4); 1173 if (iph->daddr) 1174 return t->hlen; 1175 1176 return -t->hlen; 1177 } 1178 1179 static int ipgre_header_parse(const struct sk_buff *skb, unsigned char *haddr) 1180 { 1181 const struct iphdr *iph = (const struct iphdr *) skb_mac_header(skb); 1182 memcpy(haddr, &iph->saddr, 4); 1183 return 4; 1184 } 1185 1186 static const struct header_ops ipgre_header_ops = { 1187 .create = ipgre_header, 1188 .parse = ipgre_header_parse, 1189 }; 1190 1191 #ifdef CONFIG_NET_IPGRE_BROADCAST 1192 static int ipgre_open(struct net_device *dev) 1193 { 1194 struct ip_tunnel *t = netdev_priv(dev); 1195 1196 if (ipv4_is_multicast(t->parms.iph.daddr)) { 1197 struct flowi4 fl4; 1198 struct rtable *rt; 1199 1200 rt = ip_route_output_gre(dev_net(dev), &fl4, 1201 t->parms.iph.daddr, 1202 t->parms.iph.saddr, 1203 t->parms.o_key, 1204 RT_TOS(t->parms.iph.tos), 1205 t->parms.link); 1206 if (IS_ERR(rt)) 1207 return -EADDRNOTAVAIL; 1208 dev = rt->dst.dev; 1209 ip_rt_put(rt); 1210 if (__in_dev_get_rtnl(dev) == NULL) 1211 return -EADDRNOTAVAIL; 1212 t->mlink = dev->ifindex; 1213 ip_mc_inc_group(__in_dev_get_rtnl(dev), t->parms.iph.daddr); 1214 } 1215 return 0; 1216 } 1217 1218 static int ipgre_close(struct net_device *dev) 1219 { 1220 struct ip_tunnel *t = netdev_priv(dev); 1221 1222 if (ipv4_is_multicast(t->parms.iph.daddr) && t->mlink) { 1223 struct in_device *in_dev; 1224 in_dev = inetdev_by_index(dev_net(dev), t->mlink); 1225 if (in_dev) 1226 ip_mc_dec_group(in_dev, t->parms.iph.daddr); 1227 } 1228 return 0; 1229 } 1230 1231 #endif 1232 1233 static const struct net_device_ops ipgre_netdev_ops = { 1234 .ndo_init = ipgre_tunnel_init, 1235 .ndo_uninit = ipgre_tunnel_uninit, 1236 #ifdef CONFIG_NET_IPGRE_BROADCAST 1237 .ndo_open = ipgre_open, 1238 .ndo_stop = ipgre_close, 1239 #endif 1240 .ndo_start_xmit = ipgre_tunnel_xmit, 1241 .ndo_do_ioctl = ipgre_tunnel_ioctl, 1242 .ndo_change_mtu = ipgre_tunnel_change_mtu, 1243 .ndo_get_stats = ipgre_get_stats, 1244 }; 1245 1246 static void ipgre_dev_free(struct net_device *dev) 1247 { 1248 free_percpu(dev->tstats); 1249 free_netdev(dev); 1250 } 1251 1252 static void ipgre_tunnel_setup(struct net_device *dev) 1253 { 1254 dev->netdev_ops = &ipgre_netdev_ops; 1255 dev->destructor = ipgre_dev_free; 1256 1257 dev->type = ARPHRD_IPGRE; 1258 dev->needed_headroom = LL_MAX_HEADER + sizeof(struct iphdr) + 4; 1259 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr) - 4; 1260 dev->flags = IFF_NOARP; 1261 dev->iflink = 0; 1262 dev->addr_len = 4; 1263 dev->features |= NETIF_F_NETNS_LOCAL; 1264 dev->priv_flags &= ~IFF_XMIT_DST_RELEASE; 1265 } 1266 1267 static int ipgre_tunnel_init(struct net_device *dev) 1268 { 1269 struct ip_tunnel *tunnel; 1270 struct iphdr *iph; 1271 1272 tunnel = netdev_priv(dev); 1273 iph = &tunnel->parms.iph; 1274 1275 tunnel->dev = dev; 1276 strcpy(tunnel->parms.name, dev->name); 1277 1278 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); 1279 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); 1280 1281 if (iph->daddr) { 1282 #ifdef CONFIG_NET_IPGRE_BROADCAST 1283 if (ipv4_is_multicast(iph->daddr)) { 1284 if (!iph->saddr) 1285 return -EINVAL; 1286 dev->flags = IFF_BROADCAST; 1287 dev->header_ops = &ipgre_header_ops; 1288 } 1289 #endif 1290 } else 1291 dev->header_ops = &ipgre_header_ops; 1292 1293 dev->tstats = alloc_percpu(struct pcpu_tstats); 1294 if (!dev->tstats) 1295 return -ENOMEM; 1296 1297 return 0; 1298 } 1299 1300 static void ipgre_fb_tunnel_init(struct net_device *dev) 1301 { 1302 struct ip_tunnel *tunnel = netdev_priv(dev); 1303 struct iphdr *iph = &tunnel->parms.iph; 1304 1305 tunnel->dev = dev; 1306 strcpy(tunnel->parms.name, dev->name); 1307 1308 iph->version = 4; 1309 iph->protocol = IPPROTO_GRE; 1310 iph->ihl = 5; 1311 tunnel->hlen = sizeof(struct iphdr) + 4; 1312 1313 dev_hold(dev); 1314 } 1315 1316 1317 static const struct gre_protocol ipgre_protocol = { 1318 .handler = ipgre_rcv, 1319 .err_handler = ipgre_err, 1320 }; 1321 1322 static void ipgre_destroy_tunnels(struct ipgre_net *ign, struct list_head *head) 1323 { 1324 int prio; 1325 1326 for (prio = 0; prio < 4; prio++) { 1327 int h; 1328 for (h = 0; h < HASH_SIZE; h++) { 1329 struct ip_tunnel *t; 1330 1331 t = rtnl_dereference(ign->tunnels[prio][h]); 1332 1333 while (t != NULL) { 1334 unregister_netdevice_queue(t->dev, head); 1335 t = rtnl_dereference(t->next); 1336 } 1337 } 1338 } 1339 } 1340 1341 static int __net_init ipgre_init_net(struct net *net) 1342 { 1343 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1344 int err; 1345 1346 ign->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "gre0", 1347 ipgre_tunnel_setup); 1348 if (!ign->fb_tunnel_dev) { 1349 err = -ENOMEM; 1350 goto err_alloc_dev; 1351 } 1352 dev_net_set(ign->fb_tunnel_dev, net); 1353 1354 ipgre_fb_tunnel_init(ign->fb_tunnel_dev); 1355 ign->fb_tunnel_dev->rtnl_link_ops = &ipgre_link_ops; 1356 1357 if ((err = register_netdev(ign->fb_tunnel_dev))) 1358 goto err_reg_dev; 1359 1360 rcu_assign_pointer(ign->tunnels_wc[0], 1361 netdev_priv(ign->fb_tunnel_dev)); 1362 return 0; 1363 1364 err_reg_dev: 1365 ipgre_dev_free(ign->fb_tunnel_dev); 1366 err_alloc_dev: 1367 return err; 1368 } 1369 1370 static void __net_exit ipgre_exit_net(struct net *net) 1371 { 1372 struct ipgre_net *ign; 1373 LIST_HEAD(list); 1374 1375 ign = net_generic(net, ipgre_net_id); 1376 rtnl_lock(); 1377 ipgre_destroy_tunnels(ign, &list); 1378 unregister_netdevice_many(&list); 1379 rtnl_unlock(); 1380 } 1381 1382 static struct pernet_operations ipgre_net_ops = { 1383 .init = ipgre_init_net, 1384 .exit = ipgre_exit_net, 1385 .id = &ipgre_net_id, 1386 .size = sizeof(struct ipgre_net), 1387 }; 1388 1389 static int ipgre_tunnel_validate(struct nlattr *tb[], struct nlattr *data[]) 1390 { 1391 __be16 flags; 1392 1393 if (!data) 1394 return 0; 1395 1396 flags = 0; 1397 if (data[IFLA_GRE_IFLAGS]) 1398 flags |= nla_get_be16(data[IFLA_GRE_IFLAGS]); 1399 if (data[IFLA_GRE_OFLAGS]) 1400 flags |= nla_get_be16(data[IFLA_GRE_OFLAGS]); 1401 if (flags & (GRE_VERSION|GRE_ROUTING)) 1402 return -EINVAL; 1403 1404 return 0; 1405 } 1406 1407 static int ipgre_tap_validate(struct nlattr *tb[], struct nlattr *data[]) 1408 { 1409 __be32 daddr; 1410 1411 if (tb[IFLA_ADDRESS]) { 1412 if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN) 1413 return -EINVAL; 1414 if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS]))) 1415 return -EADDRNOTAVAIL; 1416 } 1417 1418 if (!data) 1419 goto out; 1420 1421 if (data[IFLA_GRE_REMOTE]) { 1422 memcpy(&daddr, nla_data(data[IFLA_GRE_REMOTE]), 4); 1423 if (!daddr) 1424 return -EINVAL; 1425 } 1426 1427 out: 1428 return ipgre_tunnel_validate(tb, data); 1429 } 1430 1431 static void ipgre_netlink_parms(struct nlattr *data[], 1432 struct ip_tunnel_parm *parms) 1433 { 1434 memset(parms, 0, sizeof(*parms)); 1435 1436 parms->iph.protocol = IPPROTO_GRE; 1437 1438 if (!data) 1439 return; 1440 1441 if (data[IFLA_GRE_LINK]) 1442 parms->link = nla_get_u32(data[IFLA_GRE_LINK]); 1443 1444 if (data[IFLA_GRE_IFLAGS]) 1445 parms->i_flags = nla_get_be16(data[IFLA_GRE_IFLAGS]); 1446 1447 if (data[IFLA_GRE_OFLAGS]) 1448 parms->o_flags = nla_get_be16(data[IFLA_GRE_OFLAGS]); 1449 1450 if (data[IFLA_GRE_IKEY]) 1451 parms->i_key = nla_get_be32(data[IFLA_GRE_IKEY]); 1452 1453 if (data[IFLA_GRE_OKEY]) 1454 parms->o_key = nla_get_be32(data[IFLA_GRE_OKEY]); 1455 1456 if (data[IFLA_GRE_LOCAL]) 1457 parms->iph.saddr = nla_get_be32(data[IFLA_GRE_LOCAL]); 1458 1459 if (data[IFLA_GRE_REMOTE]) 1460 parms->iph.daddr = nla_get_be32(data[IFLA_GRE_REMOTE]); 1461 1462 if (data[IFLA_GRE_TTL]) 1463 parms->iph.ttl = nla_get_u8(data[IFLA_GRE_TTL]); 1464 1465 if (data[IFLA_GRE_TOS]) 1466 parms->iph.tos = nla_get_u8(data[IFLA_GRE_TOS]); 1467 1468 if (!data[IFLA_GRE_PMTUDISC] || nla_get_u8(data[IFLA_GRE_PMTUDISC])) 1469 parms->iph.frag_off = htons(IP_DF); 1470 } 1471 1472 static int ipgre_tap_init(struct net_device *dev) 1473 { 1474 struct ip_tunnel *tunnel; 1475 1476 tunnel = netdev_priv(dev); 1477 1478 tunnel->dev = dev; 1479 strcpy(tunnel->parms.name, dev->name); 1480 1481 ipgre_tunnel_bind_dev(dev); 1482 1483 dev->tstats = alloc_percpu(struct pcpu_tstats); 1484 if (!dev->tstats) 1485 return -ENOMEM; 1486 1487 return 0; 1488 } 1489 1490 static const struct net_device_ops ipgre_tap_netdev_ops = { 1491 .ndo_init = ipgre_tap_init, 1492 .ndo_uninit = ipgre_tunnel_uninit, 1493 .ndo_start_xmit = ipgre_tunnel_xmit, 1494 .ndo_set_mac_address = eth_mac_addr, 1495 .ndo_validate_addr = eth_validate_addr, 1496 .ndo_change_mtu = ipgre_tunnel_change_mtu, 1497 .ndo_get_stats = ipgre_get_stats, 1498 }; 1499 1500 static void ipgre_tap_setup(struct net_device *dev) 1501 { 1502 1503 ether_setup(dev); 1504 1505 dev->netdev_ops = &ipgre_tap_netdev_ops; 1506 dev->destructor = ipgre_dev_free; 1507 1508 dev->iflink = 0; 1509 dev->features |= NETIF_F_NETNS_LOCAL; 1510 } 1511 1512 static int ipgre_newlink(struct net *src_net, struct net_device *dev, struct nlattr *tb[], 1513 struct nlattr *data[]) 1514 { 1515 struct ip_tunnel *nt; 1516 struct net *net = dev_net(dev); 1517 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1518 int mtu; 1519 int err; 1520 1521 nt = netdev_priv(dev); 1522 ipgre_netlink_parms(data, &nt->parms); 1523 1524 if (ipgre_tunnel_find(net, &nt->parms, dev->type)) 1525 return -EEXIST; 1526 1527 if (dev->type == ARPHRD_ETHER && !tb[IFLA_ADDRESS]) 1528 random_ether_addr(dev->dev_addr); 1529 1530 mtu = ipgre_tunnel_bind_dev(dev); 1531 if (!tb[IFLA_MTU]) 1532 dev->mtu = mtu; 1533 1534 /* Can use a lockless transmit, unless we generate output sequences */ 1535 if (!(nt->parms.o_flags & GRE_SEQ)) 1536 dev->features |= NETIF_F_LLTX; 1537 1538 err = register_netdevice(dev); 1539 if (err) 1540 goto out; 1541 1542 dev_hold(dev); 1543 ipgre_tunnel_link(ign, nt); 1544 1545 out: 1546 return err; 1547 } 1548 1549 static int ipgre_changelink(struct net_device *dev, struct nlattr *tb[], 1550 struct nlattr *data[]) 1551 { 1552 struct ip_tunnel *t, *nt; 1553 struct net *net = dev_net(dev); 1554 struct ipgre_net *ign = net_generic(net, ipgre_net_id); 1555 struct ip_tunnel_parm p; 1556 int mtu; 1557 1558 if (dev == ign->fb_tunnel_dev) 1559 return -EINVAL; 1560 1561 nt = netdev_priv(dev); 1562 ipgre_netlink_parms(data, &p); 1563 1564 t = ipgre_tunnel_locate(net, &p, 0); 1565 1566 if (t) { 1567 if (t->dev != dev) 1568 return -EEXIST; 1569 } else { 1570 t = nt; 1571 1572 if (dev->type != ARPHRD_ETHER) { 1573 unsigned int nflags = 0; 1574 1575 if (ipv4_is_multicast(p.iph.daddr)) 1576 nflags = IFF_BROADCAST; 1577 else if (p.iph.daddr) 1578 nflags = IFF_POINTOPOINT; 1579 1580 if ((dev->flags ^ nflags) & 1581 (IFF_POINTOPOINT | IFF_BROADCAST)) 1582 return -EINVAL; 1583 } 1584 1585 ipgre_tunnel_unlink(ign, t); 1586 t->parms.iph.saddr = p.iph.saddr; 1587 t->parms.iph.daddr = p.iph.daddr; 1588 t->parms.i_key = p.i_key; 1589 if (dev->type != ARPHRD_ETHER) { 1590 memcpy(dev->dev_addr, &p.iph.saddr, 4); 1591 memcpy(dev->broadcast, &p.iph.daddr, 4); 1592 } 1593 ipgre_tunnel_link(ign, t); 1594 netdev_state_change(dev); 1595 } 1596 1597 t->parms.o_key = p.o_key; 1598 t->parms.iph.ttl = p.iph.ttl; 1599 t->parms.iph.tos = p.iph.tos; 1600 t->parms.iph.frag_off = p.iph.frag_off; 1601 1602 if (t->parms.link != p.link) { 1603 t->parms.link = p.link; 1604 mtu = ipgre_tunnel_bind_dev(dev); 1605 if (!tb[IFLA_MTU]) 1606 dev->mtu = mtu; 1607 netdev_state_change(dev); 1608 } 1609 1610 return 0; 1611 } 1612 1613 static size_t ipgre_get_size(const struct net_device *dev) 1614 { 1615 return 1616 /* IFLA_GRE_LINK */ 1617 nla_total_size(4) + 1618 /* IFLA_GRE_IFLAGS */ 1619 nla_total_size(2) + 1620 /* IFLA_GRE_OFLAGS */ 1621 nla_total_size(2) + 1622 /* IFLA_GRE_IKEY */ 1623 nla_total_size(4) + 1624 /* IFLA_GRE_OKEY */ 1625 nla_total_size(4) + 1626 /* IFLA_GRE_LOCAL */ 1627 nla_total_size(4) + 1628 /* IFLA_GRE_REMOTE */ 1629 nla_total_size(4) + 1630 /* IFLA_GRE_TTL */ 1631 nla_total_size(1) + 1632 /* IFLA_GRE_TOS */ 1633 nla_total_size(1) + 1634 /* IFLA_GRE_PMTUDISC */ 1635 nla_total_size(1) + 1636 0; 1637 } 1638 1639 static int ipgre_fill_info(struct sk_buff *skb, const struct net_device *dev) 1640 { 1641 struct ip_tunnel *t = netdev_priv(dev); 1642 struct ip_tunnel_parm *p = &t->parms; 1643 1644 NLA_PUT_U32(skb, IFLA_GRE_LINK, p->link); 1645 NLA_PUT_BE16(skb, IFLA_GRE_IFLAGS, p->i_flags); 1646 NLA_PUT_BE16(skb, IFLA_GRE_OFLAGS, p->o_flags); 1647 NLA_PUT_BE32(skb, IFLA_GRE_IKEY, p->i_key); 1648 NLA_PUT_BE32(skb, IFLA_GRE_OKEY, p->o_key); 1649 NLA_PUT_BE32(skb, IFLA_GRE_LOCAL, p->iph.saddr); 1650 NLA_PUT_BE32(skb, IFLA_GRE_REMOTE, p->iph.daddr); 1651 NLA_PUT_U8(skb, IFLA_GRE_TTL, p->iph.ttl); 1652 NLA_PUT_U8(skb, IFLA_GRE_TOS, p->iph.tos); 1653 NLA_PUT_U8(skb, IFLA_GRE_PMTUDISC, !!(p->iph.frag_off & htons(IP_DF))); 1654 1655 return 0; 1656 1657 nla_put_failure: 1658 return -EMSGSIZE; 1659 } 1660 1661 static const struct nla_policy ipgre_policy[IFLA_GRE_MAX + 1] = { 1662 [IFLA_GRE_LINK] = { .type = NLA_U32 }, 1663 [IFLA_GRE_IFLAGS] = { .type = NLA_U16 }, 1664 [IFLA_GRE_OFLAGS] = { .type = NLA_U16 }, 1665 [IFLA_GRE_IKEY] = { .type = NLA_U32 }, 1666 [IFLA_GRE_OKEY] = { .type = NLA_U32 }, 1667 [IFLA_GRE_LOCAL] = { .len = FIELD_SIZEOF(struct iphdr, saddr) }, 1668 [IFLA_GRE_REMOTE] = { .len = FIELD_SIZEOF(struct iphdr, daddr) }, 1669 [IFLA_GRE_TTL] = { .type = NLA_U8 }, 1670 [IFLA_GRE_TOS] = { .type = NLA_U8 }, 1671 [IFLA_GRE_PMTUDISC] = { .type = NLA_U8 }, 1672 }; 1673 1674 static struct rtnl_link_ops ipgre_link_ops __read_mostly = { 1675 .kind = "gre", 1676 .maxtype = IFLA_GRE_MAX, 1677 .policy = ipgre_policy, 1678 .priv_size = sizeof(struct ip_tunnel), 1679 .setup = ipgre_tunnel_setup, 1680 .validate = ipgre_tunnel_validate, 1681 .newlink = ipgre_newlink, 1682 .changelink = ipgre_changelink, 1683 .get_size = ipgre_get_size, 1684 .fill_info = ipgre_fill_info, 1685 }; 1686 1687 static struct rtnl_link_ops ipgre_tap_ops __read_mostly = { 1688 .kind = "gretap", 1689 .maxtype = IFLA_GRE_MAX, 1690 .policy = ipgre_policy, 1691 .priv_size = sizeof(struct ip_tunnel), 1692 .setup = ipgre_tap_setup, 1693 .validate = ipgre_tap_validate, 1694 .newlink = ipgre_newlink, 1695 .changelink = ipgre_changelink, 1696 .get_size = ipgre_get_size, 1697 .fill_info = ipgre_fill_info, 1698 }; 1699 1700 /* 1701 * And now the modules code and kernel interface. 1702 */ 1703 1704 static int __init ipgre_init(void) 1705 { 1706 int err; 1707 1708 printk(KERN_INFO "GRE over IPv4 tunneling driver\n"); 1709 1710 err = register_pernet_device(&ipgre_net_ops); 1711 if (err < 0) 1712 return err; 1713 1714 err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO); 1715 if (err < 0) { 1716 printk(KERN_INFO "ipgre init: can't add protocol\n"); 1717 goto add_proto_failed; 1718 } 1719 1720 err = rtnl_link_register(&ipgre_link_ops); 1721 if (err < 0) 1722 goto rtnl_link_failed; 1723 1724 err = rtnl_link_register(&ipgre_tap_ops); 1725 if (err < 0) 1726 goto tap_ops_failed; 1727 1728 out: 1729 return err; 1730 1731 tap_ops_failed: 1732 rtnl_link_unregister(&ipgre_link_ops); 1733 rtnl_link_failed: 1734 gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO); 1735 add_proto_failed: 1736 unregister_pernet_device(&ipgre_net_ops); 1737 goto out; 1738 } 1739 1740 static void __exit ipgre_fini(void) 1741 { 1742 rtnl_link_unregister(&ipgre_tap_ops); 1743 rtnl_link_unregister(&ipgre_link_ops); 1744 if (gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO) < 0) 1745 printk(KERN_INFO "ipgre close: can't remove protocol\n"); 1746 unregister_pernet_device(&ipgre_net_ops); 1747 } 1748 1749 module_init(ipgre_init); 1750 module_exit(ipgre_fini); 1751 MODULE_LICENSE("GPL"); 1752 MODULE_ALIAS_RTNL_LINK("gre"); 1753 MODULE_ALIAS_RTNL_LINK("gretap"); 1754 MODULE_ALIAS_NETDEV("gre0"); 1755