[POWERPC] pasemi: clean up mdio_gpio a bit
[linux-2.6] / net / ipv6 / sit.c
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_parm *parms)
103 {
104         __be32 remote = parms->iph.daddr;
105         __be32 local = 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 inline struct ip_tunnel **ipip6_bucket(struct ip_tunnel *t)
121 {
122         return __ipip6_bucket(&t->parms);
123 }
124
125 static void ipip6_tunnel_unlink(struct ip_tunnel *t)
126 {
127         struct ip_tunnel **tp;
128
129         for (tp = ipip6_bucket(t); *tp; tp = &(*tp)->next) {
130                 if (t == *tp) {
131                         write_lock_bh(&ipip6_lock);
132                         *tp = t->next;
133                         write_unlock_bh(&ipip6_lock);
134                         break;
135                 }
136         }
137 }
138
139 static void ipip6_tunnel_link(struct ip_tunnel *t)
140 {
141         struct ip_tunnel **tp = ipip6_bucket(t);
142
143         t->next = *tp;
144         write_lock_bh(&ipip6_lock);
145         *tp = t;
146         write_unlock_bh(&ipip6_lock);
147 }
148
149 static struct ip_tunnel * ipip6_tunnel_locate(struct ip_tunnel_parm *parms, int create)
150 {
151         __be32 remote = parms->iph.daddr;
152         __be32 local = parms->iph.saddr;
153         struct ip_tunnel *t, **tp, *nt;
154         struct net_device *dev;
155         char name[IFNAMSIZ];
156
157         for (tp = __ipip6_bucket(parms); (t = *tp) != NULL; tp = &t->next) {
158                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
159                         return t;
160         }
161         if (!create)
162                 goto failed;
163
164         if (parms->name[0])
165                 strlcpy(name, parms->name, IFNAMSIZ);
166         else {
167                 int i;
168                 for (i=1; i<100; i++) {
169                         sprintf(name, "sit%d", i);
170                         if (__dev_get_by_name(&init_net, name) == NULL)
171                                 break;
172                 }
173                 if (i==100)
174                         goto failed;
175         }
176
177         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
178         if (dev == NULL)
179                 return NULL;
180
181         nt = netdev_priv(dev);
182         dev->init = ipip6_tunnel_init;
183         nt->parms = *parms;
184
185         if (register_netdevice(dev) < 0) {
186                 free_netdev(dev);
187                 goto failed;
188         }
189
190         dev_hold(dev);
191
192         ipip6_tunnel_link(nt);
193         return nt;
194
195 failed:
196         return NULL;
197 }
198
199 static void ipip6_tunnel_uninit(struct net_device *dev)
200 {
201         if (dev == ipip6_fb_tunnel_dev) {
202                 write_lock_bh(&ipip6_lock);
203                 tunnels_wc[0] = NULL;
204                 write_unlock_bh(&ipip6_lock);
205                 dev_put(dev);
206         } else {
207                 ipip6_tunnel_unlink(netdev_priv(dev));
208                 dev_put(dev);
209         }
210 }
211
212
213 static int ipip6_err(struct sk_buff *skb, u32 info)
214 {
215 #ifndef I_WISH_WORLD_WERE_PERFECT
216
217 /* It is not :-( All the routers (except for Linux) return only
218    8 bytes of packet payload. It means, that precise relaying of
219    ICMP in the real Internet is absolutely infeasible.
220  */
221         struct iphdr *iph = (struct iphdr*)skb->data;
222         const int type = icmp_hdr(skb)->type;
223         const int code = icmp_hdr(skb)->code;
224         struct ip_tunnel *t;
225         int err;
226
227         switch (type) {
228         default:
229         case ICMP_PARAMETERPROB:
230                 return 0;
231
232         case ICMP_DEST_UNREACH:
233                 switch (code) {
234                 case ICMP_SR_FAILED:
235                 case ICMP_PORT_UNREACH:
236                         /* Impossible event. */
237                         return 0;
238                 case ICMP_FRAG_NEEDED:
239                         /* Soft state for pmtu is maintained by IP core. */
240                         return 0;
241                 default:
242                         /* All others are translated to HOST_UNREACH.
243                            rfc2003 contains "deep thoughts" about NET_UNREACH,
244                            I believe they are just ether pollution. --ANK
245                          */
246                         break;
247                 }
248                 break;
249         case ICMP_TIME_EXCEEDED:
250                 if (code != ICMP_EXC_TTL)
251                         return 0;
252                 break;
253         }
254
255         err = -ENOENT;
256
257         read_lock(&ipip6_lock);
258         t = ipip6_tunnel_lookup(iph->daddr, iph->saddr);
259         if (t == NULL || t->parms.iph.daddr == 0)
260                 goto out;
261
262         err = 0;
263         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
264                 goto out;
265
266         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
267                 t->err_count++;
268         else
269                 t->err_count = 1;
270         t->err_time = jiffies;
271 out:
272         read_unlock(&ipip6_lock);
273         return err;
274 #else
275         struct iphdr *iph = (struct iphdr*)dp;
276         int hlen = iph->ihl<<2;
277         struct ipv6hdr *iph6;
278         const int type = icmp_hdr(skb)->type;
279         const int code = icmp_hdr(skb)->code;
280         int rel_type = 0;
281         int rel_code = 0;
282         int rel_info = 0;
283         struct sk_buff *skb2;
284         struct rt6_info *rt6i;
285
286         if (len < hlen + sizeof(struct ipv6hdr))
287                 return;
288         iph6 = (struct ipv6hdr*)(dp + hlen);
289
290         switch (type) {
291         default:
292                 return;
293         case ICMP_PARAMETERPROB:
294                 if (icmp_hdr(skb)->un.gateway < hlen)
295                         return;
296
297                 /* So... This guy found something strange INSIDE encapsulated
298                    packet. Well, he is fool, but what can we do ?
299                  */
300                 rel_type = ICMPV6_PARAMPROB;
301                 rel_info = icmp_hdr(skb)->un.gateway - hlen;
302                 break;
303
304         case ICMP_DEST_UNREACH:
305                 switch (code) {
306                 case ICMP_SR_FAILED:
307                 case ICMP_PORT_UNREACH:
308                         /* Impossible event. */
309                         return;
310                 case ICMP_FRAG_NEEDED:
311                         /* Too complicated case ... */
312                         return;
313                 default:
314                         /* All others are translated to HOST_UNREACH.
315                            rfc2003 contains "deep thoughts" about NET_UNREACH,
316                            I believe, it is just ether pollution. --ANK
317                          */
318                         rel_type = ICMPV6_DEST_UNREACH;
319                         rel_code = ICMPV6_ADDR_UNREACH;
320                         break;
321                 }
322                 break;
323         case ICMP_TIME_EXCEEDED:
324                 if (code != ICMP_EXC_TTL)
325                         return;
326                 rel_type = ICMPV6_TIME_EXCEED;
327                 rel_code = ICMPV6_EXC_HOPLIMIT;
328                 break;
329         }
330
331         /* Prepare fake skb to feed it to icmpv6_send */
332         skb2 = skb_clone(skb, GFP_ATOMIC);
333         if (skb2 == NULL)
334                 return 0;
335         dst_release(skb2->dst);
336         skb2->dst = NULL;
337         skb_pull(skb2, skb->data - (u8*)iph6);
338         skb_reset_network_header(skb2);
339
340         /* Try to guess incoming interface */
341         rt6i = rt6_lookup(&iph6->saddr, NULL, NULL, 0);
342         if (rt6i && rt6i->rt6i_dev) {
343                 skb2->dev = rt6i->rt6i_dev;
344
345                 rt6i = rt6_lookup(&iph6->daddr, &iph6->saddr, NULL, 0);
346
347                 if (rt6i && rt6i->rt6i_dev && rt6i->rt6i_dev->type == ARPHRD_SIT) {
348                         struct ip_tunnel *t = netdev_priv(rt6i->rt6i_dev);
349                         if (rel_type == ICMPV6_TIME_EXCEED && t->parms.iph.ttl) {
350                                 rel_type = ICMPV6_DEST_UNREACH;
351                                 rel_code = ICMPV6_ADDR_UNREACH;
352                         }
353                         icmpv6_send(skb2, rel_type, rel_code, rel_info, skb2->dev);
354                 }
355         }
356         kfree_skb(skb2);
357         return 0;
358 #endif
359 }
360
361 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
362 {
363         if (INET_ECN_is_ce(iph->tos))
364                 IP6_ECN_set_ce(ipv6_hdr(skb));
365 }
366
367 static int ipip6_rcv(struct sk_buff *skb)
368 {
369         struct iphdr *iph;
370         struct ip_tunnel *tunnel;
371
372         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
373                 goto out;
374
375         iph = ip_hdr(skb);
376
377         read_lock(&ipip6_lock);
378         if ((tunnel = ipip6_tunnel_lookup(iph->saddr, iph->daddr)) != NULL) {
379                 secpath_reset(skb);
380                 skb->mac_header = skb->network_header;
381                 skb_reset_network_header(skb);
382                 IPCB(skb)->flags = 0;
383                 skb->protocol = htons(ETH_P_IPV6);
384                 skb->pkt_type = PACKET_HOST;
385                 tunnel->stat.rx_packets++;
386                 tunnel->stat.rx_bytes += skb->len;
387                 skb->dev = tunnel->dev;
388                 dst_release(skb->dst);
389                 skb->dst = NULL;
390                 nf_reset(skb);
391                 ipip6_ecn_decapsulate(iph, skb);
392                 netif_rx(skb);
393                 read_unlock(&ipip6_lock);
394                 return 0;
395         }
396
397         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
398         kfree_skb(skb);
399         read_unlock(&ipip6_lock);
400 out:
401         return 0;
402 }
403
404 /* Returns the embedded IPv4 address if the IPv6 address
405    comes from 6to4 (RFC 3056) addr space */
406
407 static inline __be32 try_6to4(struct in6_addr *v6dst)
408 {
409         __be32 dst = 0;
410
411         if (v6dst->s6_addr16[0] == htons(0x2002)) {
412                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
413                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
414         }
415         return dst;
416 }
417
418 /*
419  *      This function assumes it is being called from dev_queue_xmit()
420  *      and that skb is filled properly by that function.
421  */
422
423 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
424 {
425         struct ip_tunnel *tunnel = netdev_priv(dev);
426         struct net_device_stats *stats = &tunnel->stat;
427         struct iphdr  *tiph = &tunnel->parms.iph;
428         struct ipv6hdr *iph6 = ipv6_hdr(skb);
429         u8     tos = tunnel->parms.iph.tos;
430         struct rtable *rt;                      /* Route to the other host */
431         struct net_device *tdev;                        /* Device to other host */
432         struct iphdr  *iph;                     /* Our new IP header */
433         unsigned int max_headroom;              /* The extra header space needed */
434         __be32 dst = tiph->daddr;
435         int    mtu;
436         struct in6_addr *addr6;
437         int addr_type;
438
439         if (tunnel->recursion++) {
440                 tunnel->stat.collisions++;
441                 goto tx_error;
442         }
443
444         if (skb->protocol != htons(ETH_P_IPV6))
445                 goto tx_error;
446
447         if (!dst)
448                 dst = try_6to4(&iph6->daddr);
449
450         if (!dst) {
451                 struct neighbour *neigh = NULL;
452
453                 if (skb->dst)
454                         neigh = skb->dst->neighbour;
455
456                 if (neigh == NULL) {
457                         if (net_ratelimit())
458                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
459                         goto tx_error;
460                 }
461
462                 addr6 = (struct in6_addr*)&neigh->primary_key;
463                 addr_type = ipv6_addr_type(addr6);
464
465                 if (addr_type == IPV6_ADDR_ANY) {
466                         addr6 = &ipv6_hdr(skb)->daddr;
467                         addr_type = ipv6_addr_type(addr6);
468                 }
469
470                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
471                         goto tx_error_icmp;
472
473                 dst = addr6->s6_addr32[3];
474         }
475
476         {
477                 struct flowi fl = { .nl_u = { .ip4_u =
478                                               { .daddr = dst,
479                                                 .saddr = tiph->saddr,
480                                                 .tos = RT_TOS(tos) } },
481                                     .oif = tunnel->parms.link,
482                                     .proto = IPPROTO_IPV6 };
483                 if (ip_route_output_key(&rt, &fl)) {
484                         tunnel->stat.tx_carrier_errors++;
485                         goto tx_error_icmp;
486                 }
487         }
488         if (rt->rt_type != RTN_UNICAST) {
489                 ip_rt_put(rt);
490                 tunnel->stat.tx_carrier_errors++;
491                 goto tx_error_icmp;
492         }
493         tdev = rt->u.dst.dev;
494
495         if (tdev == dev) {
496                 ip_rt_put(rt);
497                 tunnel->stat.collisions++;
498                 goto tx_error;
499         }
500
501         if (tiph->frag_off)
502                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
503         else
504                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
505
506         if (mtu < 68) {
507                 tunnel->stat.collisions++;
508                 ip_rt_put(rt);
509                 goto tx_error;
510         }
511         if (mtu < IPV6_MIN_MTU)
512                 mtu = IPV6_MIN_MTU;
513         if (tunnel->parms.iph.daddr && skb->dst)
514                 skb->dst->ops->update_pmtu(skb->dst, mtu);
515
516         if (skb->len > mtu) {
517                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
518                 ip_rt_put(rt);
519                 goto tx_error;
520         }
521
522         if (tunnel->err_count > 0) {
523                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
524                         tunnel->err_count--;
525                         dst_link_failure(skb);
526                 } else
527                         tunnel->err_count = 0;
528         }
529
530         /*
531          * Okay, now see if we can stuff it in the buffer as-is.
532          */
533         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
534
535         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
536             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
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 = ipv6_hdr(skb);
550         }
551
552         skb->transport_header = skb->network_header;
553         skb_push(skb, sizeof(struct iphdr));
554         skb_reset_network_header(skb);
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                     =       ip_hdr(skb);
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                 unregister_netdevice(dev);
691                 err = 0;
692                 break;
693
694         default:
695                 err = -EINVAL;
696         }
697
698 done:
699         return err;
700 }
701
702 static struct net_device_stats *ipip6_tunnel_get_stats(struct net_device *dev)
703 {
704         return &(((struct ip_tunnel*)netdev_priv(dev))->stat);
705 }
706
707 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
708 {
709         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
710                 return -EINVAL;
711         dev->mtu = new_mtu;
712         return 0;
713 }
714
715 static void ipip6_tunnel_setup(struct net_device *dev)
716 {
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(&init_net, 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 xfrm_tunnel sit_handler = {
795         .handler        =       ipip6_rcv,
796         .err_handler    =       ipip6_err,
797         .priority       =       1,
798 };
799
800 static void __exit sit_destroy_tunnels(void)
801 {
802         int prio;
803
804         for (prio = 1; prio < 4; prio++) {
805                 int h;
806                 for (h = 0; h < HASH_SIZE; h++) {
807                         struct ip_tunnel *t;
808                         while ((t = tunnels[prio][h]) != NULL)
809                                 unregister_netdevice(t->dev);
810                 }
811         }
812 }
813
814 static void __exit sit_cleanup(void)
815 {
816         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
817
818         rtnl_lock();
819         sit_destroy_tunnels();
820         unregister_netdevice(ipip6_fb_tunnel_dev);
821         rtnl_unlock();
822 }
823
824 static int __init sit_init(void)
825 {
826         int err;
827
828         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
829
830         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
831                 printk(KERN_INFO "sit init: Can't add protocol\n");
832                 return -EAGAIN;
833         }
834
835         ipip6_fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
836                                            ipip6_tunnel_setup);
837         if (!ipip6_fb_tunnel_dev) {
838                 err = -ENOMEM;
839                 goto err1;
840         }
841
842         ipip6_fb_tunnel_dev->init = ipip6_fb_tunnel_init;
843
844         if ((err =  register_netdev(ipip6_fb_tunnel_dev)))
845                 goto err2;
846
847  out:
848         return err;
849  err2:
850         free_netdev(ipip6_fb_tunnel_dev);
851  err1:
852         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
853         goto out;
854 }
855
856 module_init(sit_init);
857 module_exit(sit_cleanup);
858 MODULE_LICENSE("GPL");
859 MODULE_ALIAS("sit0");