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 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) ((addr^(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(u32 remote, u32 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 u32 remote = t->parms.iph.daddr; 105 u32 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 u32 remote = parms->iph.daddr; 147 u32 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 = dev->priv; 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 /* Do not decrement MOD_USE_COUNT here. */ 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((struct ip_tunnel*)dev->priv); 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 = (struct ip_tunnel*)rt6i->rt6i_dev->priv; 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 skb->protocol = htons(ETH_P_IPV6); 385 skb->pkt_type = PACKET_HOST; 386 tunnel->stat.rx_packets++; 387 tunnel->stat.rx_bytes += skb->len; 388 skb->dev = tunnel->dev; 389 dst_release(skb->dst); 390 skb->dst = NULL; 391 nf_reset(skb); 392 ipip6_ecn_decapsulate(iph, skb); 393 netif_rx(skb); 394 read_unlock(&ipip6_lock); 395 return 0; 396 } 397 398 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PROT_UNREACH, 0); 399 kfree_skb(skb); 400 read_unlock(&ipip6_lock); 401 out: 402 return 0; 403 } 404 405 /* Returns the embedded IPv4 address if the IPv6 address 406 comes from 6to4 (RFC 3056) addr space */ 407 408 static inline u32 try_6to4(struct in6_addr *v6dst) 409 { 410 u32 dst = 0; 411 412 if (v6dst->s6_addr16[0] == htons(0x2002)) { 413 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */ 414 memcpy(&dst, &v6dst->s6_addr16[1], 4); 415 } 416 return dst; 417 } 418 419 /* 420 * This function assumes it is being called from dev_queue_xmit() 421 * and that skb is filled properly by that function. 422 */ 423 424 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev) 425 { 426 struct ip_tunnel *tunnel = (struct ip_tunnel*)dev->priv; 427 struct net_device_stats *stats = &tunnel->stat; 428 struct iphdr *tiph = &tunnel->parms.iph; 429 struct ipv6hdr *iph6 = skb->nh.ipv6h; 430 u8 tos = tunnel->parms.iph.tos; 431 struct rtable *rt; /* Route to the other host */ 432 struct net_device *tdev; /* Device to other host */ 433 struct iphdr *iph; /* Our new IP header */ 434 int max_headroom; /* The extra header space needed */ 435 u32 dst = tiph->daddr; 436 int mtu; 437 struct in6_addr *addr6; 438 int addr_type; 439 440 if (tunnel->recursion++) { 441 tunnel->stat.collisions++; 442 goto tx_error; 443 } 444 445 if (skb->protocol != htons(ETH_P_IPV6)) 446 goto tx_error; 447 448 if (!dst) 449 dst = try_6to4(&iph6->daddr); 450 451 if (!dst) { 452 struct neighbour *neigh = NULL; 453 454 if (skb->dst) 455 neigh = skb->dst->neighbour; 456 457 if (neigh == NULL) { 458 if (net_ratelimit()) 459 printk(KERN_DEBUG "sit: nexthop == NULL\n"); 460 goto tx_error; 461 } 462 463 addr6 = (struct in6_addr*)&neigh->primary_key; 464 addr_type = ipv6_addr_type(addr6); 465 466 if (addr_type == IPV6_ADDR_ANY) { 467 addr6 = &skb->nh.ipv6h->daddr; 468 addr_type = ipv6_addr_type(addr6); 469 } 470 471 if ((addr_type & IPV6_ADDR_COMPATv4) == 0) 472 goto tx_error_icmp; 473 474 dst = addr6->s6_addr32[3]; 475 } 476 477 { 478 struct flowi fl = { .nl_u = { .ip4_u = 479 { .daddr = dst, 480 .saddr = tiph->saddr, 481 .tos = RT_TOS(tos) } }, 482 .oif = tunnel->parms.link, 483 .proto = IPPROTO_IPV6 }; 484 if (ip_route_output_key(&rt, &fl)) { 485 tunnel->stat.tx_carrier_errors++; 486 goto tx_error_icmp; 487 } 488 } 489 if (rt->rt_type != RTN_UNICAST) { 490 ip_rt_put(rt); 491 tunnel->stat.tx_carrier_errors++; 492 goto tx_error_icmp; 493 } 494 tdev = rt->u.dst.dev; 495 496 if (tdev == dev) { 497 ip_rt_put(rt); 498 tunnel->stat.collisions++; 499 goto tx_error; 500 } 501 502 if (tiph->frag_off) 503 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr); 504 else 505 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu; 506 507 if (mtu < 68) { 508 tunnel->stat.collisions++; 509 ip_rt_put(rt); 510 goto tx_error; 511 } 512 if (mtu < IPV6_MIN_MTU) 513 mtu = IPV6_MIN_MTU; 514 if (tunnel->parms.iph.daddr && skb->dst) 515 skb->dst->ops->update_pmtu(skb->dst, mtu); 516 517 if (skb->len > mtu) { 518 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev); 519 ip_rt_put(rt); 520 goto tx_error; 521 } 522 523 if (tunnel->err_count > 0) { 524 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) { 525 tunnel->err_count--; 526 dst_link_failure(skb); 527 } else 528 tunnel->err_count = 0; 529 } 530 531 /* 532 * Okay, now see if we can stuff it in the buffer as-is. 533 */ 534 max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr); 535 536 if (skb_headroom(skb) < max_headroom || skb_cloned(skb) || skb_shared(skb)) { 537 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom); 538 if (!new_skb) { 539 ip_rt_put(rt); 540 stats->tx_dropped++; 541 dev_kfree_skb(skb); 542 tunnel->recursion--; 543 return 0; 544 } 545 if (skb->sk) 546 skb_set_owner_w(new_skb, skb->sk); 547 dev_kfree_skb(skb); 548 skb = new_skb; 549 iph6 = skb->nh.ipv6h; 550 } 551 552 skb->h.raw = skb->nh.raw; 553 skb->nh.raw = skb_push(skb, sizeof(struct iphdr)); 554 memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt)); 555 dst_release(skb->dst); 556 skb->dst = &rt->u.dst; 557 558 /* 559 * Push down and install the IPIP header. 560 */ 561 562 iph = skb->nh.iph; 563 iph->version = 4; 564 iph->ihl = sizeof(struct iphdr)>>2; 565 if (mtu > IPV6_MIN_MTU) 566 iph->frag_off = htons(IP_DF); 567 else 568 iph->frag_off = 0; 569 570 iph->protocol = IPPROTO_IPV6; 571 iph->tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6)); 572 iph->daddr = rt->rt_dst; 573 iph->saddr = rt->rt_src; 574 575 if ((iph->ttl = tiph->ttl) == 0) 576 iph->ttl = iph6->hop_limit; 577 578 nf_reset(skb); 579 580 IPTUNNEL_XMIT(); 581 tunnel->recursion--; 582 return 0; 583 584 tx_error_icmp: 585 dst_link_failure(skb); 586 tx_error: 587 stats->tx_errors++; 588 dev_kfree_skb(skb); 589 tunnel->recursion--; 590 return 0; 591 } 592 593 static int 594 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd) 595 { 596 int err = 0; 597 struct ip_tunnel_parm p; 598 struct ip_tunnel *t; 599 600 switch (cmd) { 601 case SIOCGETTUNNEL: 602 t = NULL; 603 if (dev == ipip6_fb_tunnel_dev) { 604 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) { 605 err = -EFAULT; 606 break; 607 } 608 t = ipip6_tunnel_locate(&p, 0); 609 } 610 if (t == NULL) 611 t = (struct ip_tunnel*)dev->priv; 612 memcpy(&p, &t->parms, sizeof(p)); 613 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) 614 err = -EFAULT; 615 break; 616 617 case SIOCADDTUNNEL: 618 case SIOCCHGTUNNEL: 619 err = -EPERM; 620 if (!capable(CAP_NET_ADMIN)) 621 goto done; 622 623 err = -EFAULT; 624 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 625 goto done; 626 627 err = -EINVAL; 628 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 || 629 p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF))) 630 goto done; 631 if (p.iph.ttl) 632 p.iph.frag_off |= htons(IP_DF); 633 634 t = ipip6_tunnel_locate(&p, cmd == SIOCADDTUNNEL); 635 636 if (dev != ipip6_fb_tunnel_dev && cmd == SIOCCHGTUNNEL) { 637 if (t != NULL) { 638 if (t->dev != dev) { 639 err = -EEXIST; 640 break; 641 } 642 } else { 643 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) || 644 (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) { 645 err = -EINVAL; 646 break; 647 } 648 t = (struct ip_tunnel*)dev->priv; 649 ipip6_tunnel_unlink(t); 650 t->parms.iph.saddr = p.iph.saddr; 651 t->parms.iph.daddr = p.iph.daddr; 652 memcpy(dev->dev_addr, &p.iph.saddr, 4); 653 memcpy(dev->broadcast, &p.iph.daddr, 4); 654 ipip6_tunnel_link(t); 655 netdev_state_change(dev); 656 } 657 } 658 659 if (t) { 660 err = 0; 661 if (cmd == SIOCCHGTUNNEL) { 662 t->parms.iph.ttl = p.iph.ttl; 663 t->parms.iph.tos = p.iph.tos; 664 } 665 if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p))) 666 err = -EFAULT; 667 } else 668 err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT); 669 break; 670 671 case SIOCDELTUNNEL: 672 err = -EPERM; 673 if (!capable(CAP_NET_ADMIN)) 674 goto done; 675 676 if (dev == ipip6_fb_tunnel_dev) { 677 err = -EFAULT; 678 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) 679 goto done; 680 err = -ENOENT; 681 if ((t = ipip6_tunnel_locate(&p, 0)) == NULL) 682 goto done; 683 err = -EPERM; 684 if (t == ipip6_fb_tunnel_dev->priv) 685 goto done; 686 dev = t->dev; 687 } 688 err = unregister_netdevice(dev); 689 break; 690 691 default: 692 err = -EINVAL; 693 } 694 695 done: 696 return err; 697 } 698 699 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev) 700 { 701 return &(((struct ip_tunnel*)dev->priv)->stat); 702 } 703 704 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu) 705 { 706 if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr)) 707 return -EINVAL; 708 dev->mtu = new_mtu; 709 return 0; 710 } 711 712 static void ipip6_tunnel_setup(struct net_device *dev) 713 { 714 SET_MODULE_OWNER(dev); 715 dev->uninit = ipip6_tunnel_uninit; 716 dev->destructor = free_netdev; 717 dev->hard_start_xmit = ipip6_tunnel_xmit; 718 dev->get_stats = ipip6_tunnel_get_stats; 719 dev->do_ioctl = ipip6_tunnel_ioctl; 720 dev->change_mtu = ipip6_tunnel_change_mtu; 721 722 dev->type = ARPHRD_SIT; 723 dev->hard_header_len = LL_MAX_HEADER + sizeof(struct iphdr); 724 dev->mtu = 1500 - sizeof(struct iphdr); 725 dev->flags = IFF_NOARP; 726 dev->iflink = 0; 727 dev->addr_len = 4; 728 } 729 730 static int ipip6_tunnel_init(struct net_device *dev) 731 { 732 struct net_device *tdev = NULL; 733 struct ip_tunnel *tunnel; 734 struct iphdr *iph; 735 736 tunnel = (struct ip_tunnel*)dev->priv; 737 iph = &tunnel->parms.iph; 738 739 tunnel->dev = dev; 740 strcpy(tunnel->parms.name, dev->name); 741 742 memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4); 743 memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4); 744 745 if (iph->daddr) { 746 struct flowi fl = { .nl_u = { .ip4_u = 747 { .daddr = iph->daddr, 748 .saddr = iph->saddr, 749 .tos = RT_TOS(iph->tos) } }, 750 .oif = tunnel->parms.link, 751 .proto = IPPROTO_IPV6 }; 752 struct rtable *rt; 753 if (!ip_route_output_key(&rt, &fl)) { 754 tdev = rt->u.dst.dev; 755 ip_rt_put(rt); 756 } 757 dev->flags |= IFF_POINTOPOINT; 758 } 759 760 if (!tdev && tunnel->parms.link) 761 tdev = __dev_get_by_index(tunnel->parms.link); 762 763 if (tdev) { 764 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr); 765 dev->mtu = tdev->mtu - sizeof(struct iphdr); 766 if (dev->mtu < IPV6_MIN_MTU) 767 dev->mtu = IPV6_MIN_MTU; 768 } 769 dev->iflink = tunnel->parms.link; 770 771 return 0; 772 } 773 774 int __init ipip6_fb_tunnel_init(struct net_device *dev) 775 { 776 struct ip_tunnel *tunnel = dev->priv; 777 struct iphdr *iph = &tunnel->parms.iph; 778 779 tunnel->dev = dev; 780 strcpy(tunnel->parms.name, dev->name); 781 782 iph->version = 4; 783 iph->protocol = IPPROTO_IPV6; 784 iph->ihl = 5; 785 iph->ttl = 64; 786 787 dev_hold(dev); 788 tunnels_wc[0] = tunnel; 789 return 0; 790 } 791 792 static struct net_protocol sit_protocol = { 793 .handler = ipip6_rcv, 794 .err_handler = ipip6_err, 795 }; 796 797 void __exit sit_cleanup(void) 798 { 799 inet_del_protocol(&sit_protocol, IPPROTO_IPV6); 800 unregister_netdev(ipip6_fb_tunnel_dev); 801 } 802 803 int __init sit_init(void) 804 { 805 int err; 806 807 printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n"); 808 809 if (inet_add_protocol(&sit_protocol, IPPROTO_IPV6) < 0) { 810 printk(KERN_INFO "sit init: Can't add protocol\n"); 811 return -EAGAIN; 812 } 813 814 ipip6_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0", 815 ipip6_tunnel_setup); 816 if (!ipip6_fb_tunnel_dev) { 817 err = -ENOMEM; 818 goto err1; 819 } 820 821 ipip6_fb_tunnel_dev->init = ipip6_fb_tunnel_init; 822 823 if ((err = register_netdev(ipip6_fb_tunnel_dev))) 824 goto err2; 825 826 out: 827 return err; 828 err2: 829 free_netdev(ipip6_fb_tunnel_dev); 830 err1: 831 inet_del_protocol(&sit_protocol, IPPROTO_IPV6); 832 goto out; 833 } 834