1 /* 2 * IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT) 3 * Linux INET6 implementation 4 * 5 * Authors: 6 * Pedro Roque <roque@di.fc.ul.pt> 7 * Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> 8 * 9 * $Id: sit.c,v 1.53 2001/09/25 05:09:53 davem Exp $ 10 * 11 * This program is free software; you can redistribute it and/or 12 * modify it under the terms of the GNU General Public License 13 * as published by the Free Software Foundation; either version 14 * 2 of the License, or (at your option) any later version. 15 * 16 * Changes: 17 * Roger Venning <r.venning@telstra.com>: 6to4 support 18 * Nate Thompson <nate@thebog.net>: 6to4 support 19 */ 20 21 #include <linux/module.h> 22 #include <linux/capability.h> 23 #include <linux/errno.h> 24 #include <linux/types.h> 25 #include <linux/socket.h> 26 #include <linux/sockios.h> 27 #include <linux/net.h> 28 #include <linux/in6.h> 29 #include <linux/netdevice.h> 30 #include <linux/if_arp.h> 31 #include <linux/icmp.h> 32 #include <asm/uaccess.h> 33 #include <linux/init.h> 34 #include <linux/netfilter_ipv4.h> 35 #include <linux/if_ether.h> 36 37 #include <net/sock.h> 38 #include <net/snmp.h> 39 40 #include <net/ipv6.h> 41 #include <net/protocol.h> 42 #include <net/transp_v6.h> 43 #include <net/ip6_fib.h> 44 #include <net/ip6_route.h> 45 #include <net/ndisc.h> 46 #include <net/addrconf.h> 47 #include <net/ip.h> 48 #include <net/udp.h> 49 #include <net/icmp.h> 50 #include <net/ipip.h> 51 #include <net/inet_ecn.h> 52 #include <net/xfrm.h> 53 #include <net/dsfield.h> 54 55 /* 56 This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c 57 58 For comments look at net/ipv4/ip_gre.c --ANK 59 */ 60 61 #define HASH_SIZE 16 62 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF) 63 64 static int ipip6_fb_tunnel_init(struct net_device *dev); 65 static int ipip6_tunnel_init(struct net_device *dev); 66 static void ipip6_tunnel_setup(struct net_device *dev); 67 68 static struct net_device *ipip6_fb_tunnel_dev; 69 70 static struct ip_tunnel *tunnels_r_l[HASH_SIZE]; 71 static struct ip_tunnel *tunnels_r[HASH_SIZE]; 72 static struct ip_tunnel *tunnels_l[HASH_SIZE]; 73 static struct ip_tunnel *tunnels_wc[1]; 74 static struct ip_tunnel **tunnels[4] = { tunnels_wc, tunnels_l, tunnels_r, tunnels_r_l }; 75 76 static DEFINE_RWLOCK(ipip6_lock); 77 78 static struct ip_tunnel * ipip6_tunnel_lookup(__be32 remote, __be32 local) 79 { 80 unsigned h0 = HASH(remote); 81 unsigned h1 = HASH(local); 82 struct ip_tunnel *t; 83 84 for (t = tunnels_r_l[h0^h1]; t; t = t->next) { 85 if (local == t->parms.iph.saddr && 86 remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP)) 87 return t; 88 } 89 for (t = tunnels_r[h0]; t; t = t->next) { 90 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP)) 91 return t; 92 } 93 for (t = tunnels_l[h1]; t; t = t->next) { 94 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP)) 95 return t; 96 } 97 if ((t = tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP)) 98 return t; 99 return NULL; 100 } 101 102 static struct ip_tunnel ** ipip6_bucket(struct ip_tunnel *t) 103 { 104 __be32 remote = t->parms.iph.daddr; 105 __be32 local = t->parms.iph.saddr; 106 unsigned h = 0; 107 int prio = 0; 108 109 if (remote) { 110 prio |= 2; 111 h ^= HASH(remote); 112 } 113 if (local) { 114 prio |= 1; 115 h ^= HASH(local); 116 } 117 return &tunnels[prio][h]; 118 } 119 120 static void ipip6_tunnel_unlink(struct ip_tunnel *t) 121 { 122 struct ip_tunnel **tp; 123 124 for (tp = ipip6_bucket(t); *tp; tp = &(*tp)->next) { 125 if (t == *tp) { 126 write_lock_bh(&ipip6_lock); 127 *tp = t->next; 128 write_unlock_bh(&ipip6_lock); 129 break; 130 } 131 } 132 } 133 134 static void ipip6_tunnel_link(struct ip_tunnel *t) 135 { 136 struct ip_tunnel **tp = ipip6_bucket(t); 137 138 t->next = *tp; 139 write_lock_bh(&ipip6_lock); 140 *tp = t; 141 write_unlock_bh(&ipip6_lock); 142 } 143 144 static struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int create) 145 { 146 __be32 remote = parms->iph.daddr; 147 __be32 local = parms->iph.saddr; 148 struct ip_tunnel *t, **tp, *nt; 149 struct net_device *dev; 150 unsigned h = 0; 151 int prio = 0; 152 char name[IFNAMSIZ]; 153 154 if (remote) { 155 prio |= 2; 156 h ^= HASH(remote); 157 } 158 if (local) { 159 prio |= 1; 160 h ^= HASH(local); 161 } 162 for (tp = &tunnels[prio][h]; (t = *tp) != NULL; tp = &t->next) { 163 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr) 164 return t; 165 } 166 if (!create) 167 goto failed; 168 169 if (parms->name[0]) 170 strlcpy(name, parms->name, IFNAMSIZ); 171 else { 172 int i; 173 for (i=1; i<100; i++) { 174 sprintf(name, "sit%d", i); 175 if (__dev_get_by_name(name) == NULL) 176 break; 177 } 178 if (i==100) 179 goto failed; 180 } 181 182 dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup); 183 if (dev == NULL) 184 return NULL; 185 186 nt = netdev_priv(dev); 187 dev->init = ipip6_tunnel_init; 188 nt->parms = *parms; 189 190 if (register_netdevice(dev) < 0) { 191 free_netdev(dev); 192 goto failed; 193 } 194 195 dev_hold(dev); 196 197 ipip6_tunnel_link(nt); 198 return nt; 199 200 failed: 201 return NULL; 202 } 203 204 static void ipip6_tunnel_uninit(struct net_device *dev) 205 { 206 if (dev == ipip6_fb_tunnel_dev) { 207 write_lock_bh(&ipip6_lock); 208 tunnels_wc[0] = NULL; 209 write_unlock_bh(&ipip6_lock); 210 dev_put(dev); 211 } else { 212 ipip6_tunnel_unlink(netdev_priv(dev)); 213 dev_put(dev); 214 } 215 } 216 217 218 static int ipip6_err(struct sk_buff *skb, u32 info) 219 { 220 #ifndef I_WISH_WORLD_WERE_PERFECT 221 222 /* It is not :-( All the routers (except for Linux) return only 223 8 bytes of packet payload. It means, that precise relaying of 224 ICMP in the real Internet is absolutely infeasible. 225 */ 226 struct iphdr *iph = (struct iphdr*)skb->data; 227 int type = skb->h.icmph->type; 228 int code = skb->h.icmph->code; 229 struct ip_tunnel *t; 230 int err; 231 232 switch (type) { 233 default: 234 case ICMP_PARAMETERPROB: 235 return 0; 236 237 case ICMP_DEST_UNREACH: 238 switch (code) { 239 case ICMP_SR_FAILED: 240 case ICMP_PORT_UNREACH: 241 /* Impossible event. */ 242 return 0; 243 case ICMP_FRAG_NEEDED: 244 /* Soft state for pmtu is maintained by IP core. */ 245 return 0; 246 default: 247 /* All others are translated to HOST_UNREACH. 248 rfc2003 contains "deep thoughts" about NET_UNREACH, 249 I believe they are just ether pollution. --ANK 250 */ 251 break; 252 } 253 break; 254 case ICMP_TIME_EXCEEDED: 255 if (code != ICMP_EXC_TTL) 256 return 0; 257 break; 258 } 259 260 err = -ENOENT; 261 262 read_lock(&ipip6_lock); 263 t = ipip6_tunnel_lookup(iph->daddr, iph->saddr); 264 if (t == NULL || t->parms.iph.daddr == 0) 265 goto out; 266 267 err = 0; 268 if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED) 269 goto out; 270 271 if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO) 272 t->err_count++; 273 else 274 t->err_count = 1; 275 t->err_time = jiffies; 276 out: 277 read_unlock(&ipip6_lock); 278 return err; 279 #else 280 struct iphdr *iph = (struct iphdr*)dp; 281 int hlen = iph->ihl<<2; 282 struct ipv6hdr *iph6; 283 int type = skb->h.icmph->type; 284 int code = skb->h.icmph->code; 285 int rel_type = 0; 286 int rel_code = 0; 287 int rel_info = 0; 288 struct sk_buff *skb2; 289 struct rt6_info *rt6i; 290 291 if (len < hlen + sizeof(struct ipv6hdr)) 292 return; 293 iph6 = (struct ipv6hdr*)(dp + hlen); 294 295 switch (type) { 296 default: 297 return; 298 case ICMP_PARAMETERPROB: 299 if (skb->h.icmph->un.gateway < hlen) 300 return; 301 302 /* So... This guy found something strange INSIDE encapsulated 303 packet. Well, he is fool, but what can we do ? 304 */ 305 rel_type = ICMPV6_PARAMPROB; 306 rel_info = skb->h.icmph->un.gateway - hlen; 307 break; 308 309 case ICMP_DEST_UNREACH: 310 switch (code) { 311 case ICMP_SR_FAILED: 312 case ICMP_PORT_UNREACH: 313 /* Impossible event. */ 314 return; 315 case ICMP_FRAG_NEEDED: 316 /* Too complicated case ... */ 317 return; 318 default: 319 /* All others are translated to HOST_UNREACH. 320 rfc2003 contains "deep thoughts" about NET_UNREACH, 321 I believe, it is just ether pollution. --ANK 322 */ 323 rel_type = ICMPV6_DEST_UNREACH; 324 rel_code = ICMPV6_ADDR_UNREACH; 325 break; 326 } 327 break; 328 case ICMP_TIME_EXCEEDED: 329 if (code != ICMP_EXC_TTL) 330 return; 331 rel_type = ICMPV6_TIME_EXCEED; 332 rel_code = ICMPV6_EXC_HOPLIMIT; 333 break; 334 } 335 336 /* Prepare fake skb to feed it to icmpv6_send */ 337 skb2 = skb_clone(skb, GFP_ATOMIC); 338 if (skb2 == NULL) 339 return 0; 340 dst_release(skb2->dst); 341 skb2->dst = NULL; 342 skb_pull(skb2, skb->data - (u8*)iph6); 343 skb2->nh.raw = skb2->data; 344 345 /* Try to guess incoming interface */ 346 rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0); 347 if (rt6i && rt6i->rt6i_dev) { 348 skb2->dev = rt6i->rt6i_dev; 349 350 rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0); 351 352 if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) { 353 struct ip_tunnel *t = netdev_priv(rt6i->rt6i_dev); 354 if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) { 355 rel_type = ICMPV6_DEST_UNREACH; 356 rel_code = ICMPV6_ADDR_UNREACH; 357 } 358 icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev); 359 } 360 } 361 kfree_skb(skb2); 362 return 0; 363 #endif 364 } 365 366 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb) 367 { 368 if (INET_ECN_is_ce(iph->tos)) 369 IP6_ECN_set_ce(skb->nh.ipv6h); 370 } 371 372 static int ipip6_rcv(struct sk_buff *skb) 373 { 374 struct iphdr *iph; 375 struct ip_tunnel *tunnel; 376 377 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr))) 378 goto out; 379 380 iph = skb->nh.iph; 381 382 read_lock(&ipip6_lock); 383 if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) { 384 secpath_reset(skb); 385 skb->mac.raw = skb->nh.raw; 386 skb->nh.raw = skb->data; 387 IPCB(skb)->flags = 0; 388 skb->protocol = htons(ETH_P_IPV6); 389 skb->pkt_type = PACKET_HOST; 390 tunnel->stat.rx_packets++; 391 tunnel->stat.rx_bytes += skb->len; 392 skb->dev = tunnel->dev; 393 dst_release(skb->dst); 394 skb->dst = NULL; 395 nf_reset(skb); 396 ipip6_ecn_decapsulate(iph, skb); 397 netif_rx(skb); 398 read_unlock(&ipip6_lock); 399 return 0; 400 } 401 402 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0); 403 kfree_skb(skb); 404 read_unlock(&ipip6_lock); 405 out: 406 return 0; 407 } 408 409 /* Returns the embedded IPv4 address if the IPv6 address 410 comes from 6to4 (RFC 3056) addr space */ 411 412 static inline __be32 try_6to4(struct in6_addr *v6dst) 413 { 414 __be32 dst = 0; 415 416 if (v6dst->s6_addr16[0] == htons(0x2002)) { 417 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */ 418 memcpy(&dst, &v6dst->s6_addr16[1], 4); 419 } 420 return dst; 421 } 422 423 /* 424 * This function assumes it is being called from dev_queue_xmit() 425 * and that skb is filled properly by that function. 426 */ 427 428 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 429 { 430 struct ip_tunnel *tunnel = netdev_priv(dev); 431 struct net_device_stats *stats = &tunnel->stat; 432 struct iphdr *tiph = &tunnel->parms.iph; 433 struct ipv6hdr *iph6 = skb->nh.ipv6h; 434 u8 tos = tunnel->parms.iph.tos; 435 struct rtable *rt; /* Route to the other host */ 436 struct net_device *tdev; /* Device to other host */ 437 struct iphdr *iph; /* Our new IP header */ 438 int max_headroom; /* The extra header space needed */ 439 __be32 dst = tiph->daddr; 440 int mtu; 441 struct in6_addr *addr6; 442 int addr_type; 443 444 if (tunnel->recursion++) { 445 tunnel->stat.collisions++; 446 goto tx_error; 447 } 448 449 if (skb->protocol != htons(ETH_P_IPV6)) 450 goto tx_error; 451 452 if (!dst) 453 dst = try_6to4(&iph6->daddr); 454 455 if (!dst) { 456 struct neighbour *neigh = NULL; 457 458 if (skb->dst) 459 neigh = skb->dst->neighbour; 460 461 if (neigh == NULL) { 462 if (net_ratelimit()) 463 printk(KERN_DEBUG "sit: nexthop == NULL\n"); 464 goto tx_error; 465 } 466 467 addr6 = (struct in6_addr*)&neigh->primary_key; 468 addr_type = ipv6_addr_type(addr6); 469 470 if (addr_type == IPV6_ADDR_ANY) { 471 addr6 = &skb->nh.ipv6h->daddr; 472 addr_type = ipv6_addr_type(addr6); 473 } 474 475 if ((addr_type & IPV6_ADDR_COMPATv4) == 0) 476 goto tx_error_icmp; 477 478 dst = addr6->s6_addr32[3]; 479 } 480 481 { 482 struct flowi fl = { .nl_u = { .ip4_u = 483 { .daddr = dst, 484 .saddr = tiph->saddr, 485 .tos = RT_TOS(tos) } }, 486 .oif = tunnel->parms.link, 487 .proto = IPPROTO_IPV6 }; 488 if (ip_route_output_key(&rt, &fl)) { 489 tunnel->stat.tx_carrier_errors++; 490 goto tx_error_icmp; 491 } 492 } 493 if (rt->rt_type != RTN_UNICAST) { 494 ip_rt_put(rt); 495 tunnel->stat.tx_carrier_errors++; 496 goto tx_error_icmp; 497 } 498 tdev = rt->u.dst.dev; 499 500 if (tdev == dev) { 501 ip_rt_put(rt); 502 tunnel->stat.collisions++; 503 goto tx_error; 504 } 505 506 if (tiph->frag_off) 507 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr); 508 else 509 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu; 510 511 if (mtu < 68) { 512 tunnel->stat.collisions++; 513 ip_rt_put(rt); 514 goto tx_error; 515 } 516 if (mtu < IPV6_MIN_MTU) 517 mtu = IPV6_MIN_MTU; 518 if (tunnel->parms.iph.daddr && skb->dst) 519 skb->dst->ops->update_pmtu(skb->dst, mtu); 520 521 if (skb->len > mtu) { 522 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev); 523 ip_rt_put(rt); 524 goto tx_error; 525 } 526 527 if (tunnel->err_count > 0) { 528 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) { 529 tunnel->err_count--; 530 dst_link_failure(skb); 531 } else 532 tunnel->err_count = 0; 533 } 534 535 /* 536 * Okay, now see if we can stuff it in the buffer as-is. 537 */ 538 max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr); 539 540 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { 541 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 542 if (!new_skb) { 543 ip_rt_put(rt); 544 stats->tx_dropped++; 545 dev_kfree_skb(skb); 546 tunnel->recursion--; 547 return 0; 548 } 549 if (skb->sk) 550 skb_set_owner_w(new_skb, skb->sk); 551 dev_kfree_skb(skb); 552 skb = new_skb; 553 iph6 = skb->nh.ipv6h; 554 } 555 556 skb->h.raw = skb->nh.raw; 557 skb->nh.raw = skb_push(skb, sizeof(struct iphdr)); 558 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 559 IPCB(skb)->flags = 0; 560 dst_release(skb->dst); 561 skb->dst = &rt->u.dst; 562 563 /* 564 * Push down and install the IPIP header. 565 */ 566 567 iph = skb->nh.iph; 568 iph->version = 4; 569 iph->ihl = sizeof(struct iphdr)>>2; 570 if (mtu > IPV6_MIN_MTU) 571 iph->frag_off = htons(IP_DF); 572 else 573 iph->frag_off = 0; 574 575 iph->protocol = IPPROTO_IPV6; 576 iph->tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6)); 577 iph->daddr = rt->rt_dst; 578 iph->saddr = rt->rt_src; 579 580 if ((iph->ttl = tiph->ttl) == 0) 581 iph->ttl = iph6->hop_limit; 582 583 nf_reset(skb); 584 585 IPTUNNEL_XMIT(); 586 tunnel->recursion--; 587 return 0; 588 589 tx_error_icmp: 590 dst_link_failure(skb); 591 tx_error: 592 stats->tx_errors++; 593 dev_kfree_skb(skb); 594 tunnel->recursion--; 595 return 0; 596 } 597 598 static int 599 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) 600 { 601 int err = 0; 602 struct ip_tunnel_parm p; 603 struct ip_tunnel *t; 604 605 switch (cmd) { 606 case SIOCGETTUNNEL: 607 t = NULL; 608 if (dev == ipip6_fb_tunnel_dev) { 609 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) { 610 err = -EFAULT; 611 break; 612 } 613 t = ipip6_tunnel_locate(&p, 0); 614 } 615 if (t == NULL) 616 t = netdev_priv(dev); 617 memcpy(&p, &t->parms, sizeof(p)); 618 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 619 err = -EFAULT; 620 break; 621 622 case SIOCADDTUNNEL: 623 case SIOCCHGTUNNEL: 624 err = -EPERM; 625 if (!capable(CAP_NET_ADMIN)) 626 goto done; 627 628 err = -EFAULT; 629 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 630 goto done; 631 632 err = -EINVAL; 633 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 || 634 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF))) 635 goto done; 636 if (p.iph.ttl) 637 p.iph.frag_off |= htons(IP_DF); 638 639 t = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL); 640 641 if (dev != ipip6_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) { 642 if (t != NULL) { 643 if (t->dev != dev) { 644 err = -EEXIST; 645 break; 646 } 647 } else { 648 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) || 649 (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) { 650 err = -EINVAL; 651 break; 652 } 653 t = netdev_priv(dev); 654 ipip6_tunnel_unlink(t); 655 t->parms.iph.saddr = p.iph.saddr; 656 t->parms.iph.daddr = p.iph.daddr; 657 memcpy(dev->dev_addr, &p.iph.saddr, 4); 658 memcpy(dev->broadcast, &p.iph.daddr, 4); 659 ipip6_tunnel_link(t); 660 netdev_state_change(dev); 661 } 662 } 663 664 if (t) { 665 err = 0; 666 if (cmd == SIOCCHGTUNNEL) { 667 t->parms.iph.ttl = p.iph.ttl; 668 t->parms.iph.tos = p.iph.tos; 669 } 670 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) 671 err = -EFAULT; 672 } else 673 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT); 674 break; 675 676 case SIOCDELTUNNEL: 677 err = -EPERM; 678 if (!capable(CAP_NET_ADMIN)) 679 goto done; 680 681 if (dev == ipip6_fb_tunnel_dev) { 682 err = -EFAULT; 683 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 684 goto done; 685 err = -ENOENT; 686 if ((t = ipip6_tunnel_locate(&p, 0)) == NULL) 687 goto done; 688 err = -EPERM; 689 if (t == netdev_priv(ipip6_fb_tunnel_dev)) 690 goto done; 691 dev = t->dev; 692 } 693 unregister_netdevice(dev); 694 err = 0; 695 break; 696 697 default: 698 err = -EINVAL; 699 } 700 701 done: 702 return err; 703 } 704 705 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev) 706 { 707 return &(((struct ip_tunnel*)netdev_priv(dev))->stat); 708 } 709 710 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu) 711 { 712 if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr)) 713 return -EINVAL; 714 dev->mtu = new_mtu; 715 return 0; 716 } 717 718 static void ipip6_tunnel_setup(struct net_device *dev) 719 { 720 SET_MODULE_OWNER(dev); 721 dev->uninit = ipip6_tunnel_uninit; 722 dev->destructor = free_netdev; 723 dev->hard_start_xmit = ipip6_tunnel_xmit; 724 dev->get_stats = ipip6_tunnel_get_stats; 725 dev->do_ioctl = ipip6_tunnel_ioctl; 726 dev->change_mtu = ipip6_tunnel_change_mtu; 727 728 dev->type = ARPHRD_SIT; 729 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 730 dev->mtu = ETH_DATA_LEN - sizeof(struct iphdr); 731 dev->flags = IFF_NOARP; 732 dev->iflink = 0; 733 dev->addr_len = 4; 734 } 735 736 static int ipip6_tunnel_init(struct net_device *dev) 737 { 738 struct net_device *tdev = NULL; 739 struct ip_tunnel *tunnel; 740 struct iphdr *iph; 741 742 tunnel = netdev_priv(dev); 743 iph = &tunnel->parms.iph; 744 745 tunnel->dev = dev; 746 strcpy(tunnel->parms.name, dev->name); 747 748 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); 749 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); 750 751 if (iph->daddr) { 752 struct flowi fl = { .nl_u = { .ip4_u = 753 { .daddr = iph->daddr, 754 .saddr = iph->saddr, 755 .tos = RT_TOS(iph->tos) } }, 756 .oif = tunnel->parms.link, 757 .proto = IPPROTO_IPV6 }; 758 struct rtable *rt; 759 if (!ip_route_output_key(&rt, &fl)) { 760 tdev = rt->u.dst.dev; 761 ip_rt_put(rt); 762 } 763 dev->flags |= IFF_POINTOPOINT; 764 } 765 766 if (!tdev && tunnel->parms.link) 767 tdev = __dev_get_by_index(tunnel->parms.link); 768 769 if (tdev) { 770 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr); 771 dev->mtu = tdev->mtu - sizeof(struct iphdr); 772 if (dev->mtu < IPV6_MIN_MTU) 773 dev->mtu = IPV6_MIN_MTU; 774 } 775 dev->iflink = tunnel->parms.link; 776 777 return 0; 778 } 779 780 static int __init ipip6_fb_tunnel_init(struct net_device *dev) 781 { 782 struct ip_tunnel *tunnel = netdev_priv(dev); 783 struct iphdr *iph = &tunnel->parms.iph; 784 785 tunnel->dev = dev; 786 strcpy(tunnel->parms.name, dev->name); 787 788 iph->version = 4; 789 iph->protocol = IPPROTO_IPV6; 790 iph->ihl = 5; 791 iph->ttl = 64; 792 793 dev_hold(dev); 794 tunnels_wc[0] = tunnel; 795 return 0; 796 } 797 798 static struct xfrm_tunnel sit_handler = { 799 .handler = ipip6_rcv, 800 .err_handler = ipip6_err, 801 .priority = 1, 802 }; 803 804 static void __exit sit_destroy_tunnels(void) 805 { 806 int prio; 807 808 for (prio = 1; prio < 4; prio++) { 809 int h; 810 for (h = 0; h < HASH_SIZE; h++) { 811 struct ip_tunnel *t; 812 while ((t = tunnels[prio][h]) != NULL) 813 unregister_netdevice(t->dev); 814 } 815 } 816 } 817 818 static void __exit sit_cleanup(void) 819 { 820 xfrm4_tunnel_deregister(&sit_handler, AF_INET6); 821 822 rtnl_lock(); 823 sit_destroy_tunnels(); 824 unregister_netdevice(ipip6_fb_tunnel_dev); 825 rtnl_unlock(); 826 } 827 828 static int __init sit_init(void) 829 { 830 int err; 831 832 printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n"); 833 834 if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) { 835 printk(KERN_INFO "sit init: Can't add protocol\n"); 836 return -EAGAIN; 837 } 838 839 ipip6_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0", 840 ipip6_tunnel_setup); 841 if (!ipip6_fb_tunnel_dev) { 842 err = -ENOMEM; 843 goto err1; 844 } 845 846 ipip6_fb_tunnel_dev->init = ipip6_fb_tunnel_init; 847 848 if ((err = register_netdev(ipip6_fb_tunnel_dev))) 849 goto err2; 850 851 out: 852 return err; 853 err2: 854 free_netdev(ipip6_fb_tunnel_dev); 855 err1: 856 xfrm4_tunnel_deregister(&sit_handler, AF_INET6); 857 goto out; 858 } 859 860 module_init(sit_init); 861 module_exit(sit_cleanup); 862 MODULE_LICENSE("GPL"); 863 MODULE_ALIAS("sit0"); 864