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