x86/PCI: remove redundant warnings
[linux-2.6.git] / 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  *      This program is free software; you can redistribute it and/or
10  *      modify it under the terms of the GNU General Public License
11  *      as published by the Free Software Foundation; either version
12  *      2 of the License, or (at your option) any later version.
13  *
14  *      Changes:
15  * Roger Venning <r.venning@telstra.com>:       6to4 support
16  * Nate Thompson <nate@thebog.net>:             6to4 support
17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
18  */
19
20 #include <linux/module.h>
21 #include <linux/capability.h>
22 #include <linux/errno.h>
23 #include <linux/types.h>
24 #include <linux/socket.h>
25 #include <linux/sockios.h>
26 #include <linux/net.h>
27 #include <linux/in6.h>
28 #include <linux/netdevice.h>
29 #include <linux/if_arp.h>
30 #include <linux/icmp.h>
31 #include <asm/uaccess.h>
32 #include <linux/init.h>
33 #include <linux/netfilter_ipv4.h>
34 #include <linux/if_ether.h>
35
36 #include <net/sock.h>
37 #include <net/snmp.h>
38
39 #include <net/ipv6.h>
40 #include <net/protocol.h>
41 #include <net/transp_v6.h>
42 #include <net/ip6_fib.h>
43 #include <net/ip6_route.h>
44 #include <net/ndisc.h>
45 #include <net/addrconf.h>
46 #include <net/ip.h>
47 #include <net/udp.h>
48 #include <net/icmp.h>
49 #include <net/ipip.h>
50 #include <net/inet_ecn.h>
51 #include <net/xfrm.h>
52 #include <net/dsfield.h>
53 #include <net/net_namespace.h>
54 #include <net/netns/generic.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) (((__force u32)addr^((__force u32)addr>>4))&0xF)
64
65 static void ipip6_tunnel_init(struct net_device *dev);
66 static void ipip6_tunnel_setup(struct net_device *dev);
67
68 static int sit_net_id __read_mostly;
69 struct sit_net {
70         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
71         struct ip_tunnel *tunnels_r[HASH_SIZE];
72         struct ip_tunnel *tunnels_l[HASH_SIZE];
73         struct ip_tunnel *tunnels_wc[1];
74         struct ip_tunnel **tunnels[4];
75
76         struct net_device *fb_tunnel_dev;
77 };
78
79 /*
80  * Locking : hash tables are protected by RCU and a spinlock
81  */
82 static DEFINE_SPINLOCK(ipip6_lock);
83
84 #define for_each_ip_tunnel_rcu(start) \
85         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
86
87 /*
88  * Must be invoked with rcu_read_lock
89  */
90 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
91                 struct net_device *dev, __be32 remote, __be32 local)
92 {
93         unsigned h0 = HASH(remote);
94         unsigned h1 = HASH(local);
95         struct ip_tunnel *t;
96         struct sit_net *sitn = net_generic(net, sit_net_id);
97
98         for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
99                 if (local == t->parms.iph.saddr &&
100                     remote == t->parms.iph.daddr &&
101                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
102                     (t->dev->flags & IFF_UP))
103                         return t;
104         }
105         for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
106                 if (remote == t->parms.iph.daddr &&
107                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
108                     (t->dev->flags & IFF_UP))
109                         return t;
110         }
111         for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
112                 if (local == t->parms.iph.saddr &&
113                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
114                     (t->dev->flags & IFF_UP))
115                         return t;
116         }
117         t = rcu_dereference(sitn->tunnels_wc[0]);
118         if ((t != NULL) && (t->dev->flags & IFF_UP))
119                 return t;
120         return NULL;
121 }
122
123 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
124                 struct ip_tunnel_parm *parms)
125 {
126         __be32 remote = parms->iph.daddr;
127         __be32 local = parms->iph.saddr;
128         unsigned h = 0;
129         int prio = 0;
130
131         if (remote) {
132                 prio |= 2;
133                 h ^= HASH(remote);
134         }
135         if (local) {
136                 prio |= 1;
137                 h ^= HASH(local);
138         }
139         return &sitn->tunnels[prio][h];
140 }
141
142 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
143                 struct ip_tunnel *t)
144 {
145         return __ipip6_bucket(sitn, &t->parms);
146 }
147
148 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
149 {
150         struct ip_tunnel **tp;
151
152         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
153                 if (t == *tp) {
154                         spin_lock_bh(&ipip6_lock);
155                         *tp = t->next;
156                         spin_unlock_bh(&ipip6_lock);
157                         break;
158                 }
159         }
160 }
161
162 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
163 {
164         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
165
166         spin_lock_bh(&ipip6_lock);
167         t->next = *tp;
168         rcu_assign_pointer(*tp, t);
169         spin_unlock_bh(&ipip6_lock);
170 }
171
172 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
173 {
174 #ifdef CONFIG_IPV6_SIT_6RD
175         struct ip_tunnel *t = netdev_priv(dev);
176
177         if (t->dev == sitn->fb_tunnel_dev) {
178                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
179                 t->ip6rd.relay_prefix = 0;
180                 t->ip6rd.prefixlen = 16;
181                 t->ip6rd.relay_prefixlen = 0;
182         } else {
183                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
184                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
185         }
186 #endif
187 }
188
189 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
190                 struct ip_tunnel_parm *parms, int create)
191 {
192         __be32 remote = parms->iph.daddr;
193         __be32 local = parms->iph.saddr;
194         struct ip_tunnel *t, **tp, *nt;
195         struct net_device *dev;
196         char name[IFNAMSIZ];
197         struct sit_net *sitn = net_generic(net, sit_net_id);
198
199         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
200                 if (local == t->parms.iph.saddr &&
201                     remote == t->parms.iph.daddr &&
202                     parms->link == t->parms.link) {
203                         if (create)
204                                 return NULL;
205                         else
206                                 return t;
207                 }
208         }
209         if (!create)
210                 goto failed;
211
212         if (parms->name[0])
213                 strlcpy(name, parms->name, IFNAMSIZ);
214         else
215                 sprintf(name, "sit%%d");
216
217         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
218         if (dev == NULL)
219                 return NULL;
220
221         dev_net_set(dev, net);
222
223         if (strchr(name, '%')) {
224                 if (dev_alloc_name(dev, name) < 0)
225                         goto failed_free;
226         }
227
228         nt = netdev_priv(dev);
229
230         nt->parms = *parms;
231         ipip6_tunnel_init(dev);
232         ipip6_tunnel_clone_6rd(dev, sitn);
233
234         if (parms->i_flags & SIT_ISATAP)
235                 dev->priv_flags |= IFF_ISATAP;
236
237         if (register_netdevice(dev) < 0)
238                 goto failed_free;
239
240         dev_hold(dev);
241
242         ipip6_tunnel_link(sitn, nt);
243         return nt;
244
245 failed_free:
246         free_netdev(dev);
247 failed:
248         return NULL;
249 }
250
251 static DEFINE_SPINLOCK(ipip6_prl_lock);
252
253 #define for_each_prl_rcu(start)                 \
254         for (prl = rcu_dereference(start);      \
255              prl;                               \
256              prl = rcu_dereference(prl->next))
257
258 static struct ip_tunnel_prl_entry *
259 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
260 {
261         struct ip_tunnel_prl_entry *prl;
262
263         for_each_prl_rcu(t->prl)
264                 if (prl->addr == addr)
265                         break;
266         return prl;
267
268 }
269
270 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
271                                 struct ip_tunnel_prl __user *a)
272 {
273         struct ip_tunnel_prl kprl, *kp;
274         struct ip_tunnel_prl_entry *prl;
275         unsigned int cmax, c = 0, ca, len;
276         int ret = 0;
277
278         if (copy_from_user(&kprl, a, sizeof(kprl)))
279                 return -EFAULT;
280         cmax = kprl.datalen / sizeof(kprl);
281         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
282                 cmax = 1;
283
284         /* For simple GET or for root users,
285          * we try harder to allocate.
286          */
287         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
288                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
289                 NULL;
290
291         rcu_read_lock();
292
293         ca = t->prl_count < cmax ? t->prl_count : cmax;
294
295         if (!kp) {
296                 /* We don't try hard to allocate much memory for
297                  * non-root users.
298                  * For root users, retry allocating enough memory for
299                  * the answer.
300                  */
301                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
302                 if (!kp) {
303                         ret = -ENOMEM;
304                         goto out;
305                 }
306         }
307
308         c = 0;
309         for_each_prl_rcu(t->prl) {
310                 if (c >= cmax)
311                         break;
312                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
313                         continue;
314                 kp[c].addr = prl->addr;
315                 kp[c].flags = prl->flags;
316                 c++;
317                 if (kprl.addr != htonl(INADDR_ANY))
318                         break;
319         }
320 out:
321         rcu_read_unlock();
322
323         len = sizeof(*kp) * c;
324         ret = 0;
325         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
326                 ret = -EFAULT;
327
328         kfree(kp);
329
330         return ret;
331 }
332
333 static int
334 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
335 {
336         struct ip_tunnel_prl_entry *p;
337         int err = 0;
338
339         if (a->addr == htonl(INADDR_ANY))
340                 return -EINVAL;
341
342         spin_lock(&ipip6_prl_lock);
343
344         for (p = t->prl; p; p = p->next) {
345                 if (p->addr == a->addr) {
346                         if (chg) {
347                                 p->flags = a->flags;
348                                 goto out;
349                         }
350                         err = -EEXIST;
351                         goto out;
352                 }
353         }
354
355         if (chg) {
356                 err = -ENXIO;
357                 goto out;
358         }
359
360         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
361         if (!p) {
362                 err = -ENOBUFS;
363                 goto out;
364         }
365
366         p->next = t->prl;
367         p->addr = a->addr;
368         p->flags = a->flags;
369         t->prl_count++;
370         rcu_assign_pointer(t->prl, p);
371 out:
372         spin_unlock(&ipip6_prl_lock);
373         return err;
374 }
375
376 static void prl_entry_destroy_rcu(struct rcu_head *head)
377 {
378         kfree(container_of(head, struct ip_tunnel_prl_entry, rcu_head));
379 }
380
381 static void prl_list_destroy_rcu(struct rcu_head *head)
382 {
383         struct ip_tunnel_prl_entry *p, *n;
384
385         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
386         do {
387                 n = p->next;
388                 kfree(p);
389                 p = n;
390         } while (p);
391 }
392
393 static int
394 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
395 {
396         struct ip_tunnel_prl_entry *x, **p;
397         int err = 0;
398
399         spin_lock(&ipip6_prl_lock);
400
401         if (a && a->addr != htonl(INADDR_ANY)) {
402                 for (p = &t->prl; *p; p = &(*p)->next) {
403                         if ((*p)->addr == a->addr) {
404                                 x = *p;
405                                 *p = x->next;
406                                 call_rcu(&x->rcu_head, prl_entry_destroy_rcu);
407                                 t->prl_count--;
408                                 goto out;
409                         }
410                 }
411                 err = -ENXIO;
412         } else {
413                 if (t->prl) {
414                         t->prl_count = 0;
415                         x = t->prl;
416                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
417                         t->prl = NULL;
418                 }
419         }
420 out:
421         spin_unlock(&ipip6_prl_lock);
422         return err;
423 }
424
425 static int
426 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
427 {
428         struct ip_tunnel_prl_entry *p;
429         int ok = 1;
430
431         rcu_read_lock();
432         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
433         if (p) {
434                 if (p->flags & PRL_DEFAULT)
435                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
436                 else
437                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
438         } else {
439                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
440                 if (ipv6_addr_is_isatap(addr6) &&
441                     (addr6->s6_addr32[3] == iph->saddr) &&
442                     ipv6_chk_prefix(addr6, t->dev))
443                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
444                 else
445                         ok = 0;
446         }
447         rcu_read_unlock();
448         return ok;
449 }
450
451 static void ipip6_tunnel_uninit(struct net_device *dev)
452 {
453         struct net *net = dev_net(dev);
454         struct sit_net *sitn = net_generic(net, sit_net_id);
455
456         if (dev == sitn->fb_tunnel_dev) {
457                 spin_lock_bh(&ipip6_lock);
458                 sitn->tunnels_wc[0] = NULL;
459                 spin_unlock_bh(&ipip6_lock);
460                 dev_put(dev);
461         } else {
462                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
463                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
464                 dev_put(dev);
465         }
466 }
467
468
469 static int ipip6_err(struct sk_buff *skb, u32 info)
470 {
471
472 /* All the routers (except for Linux) return only
473    8 bytes of packet payload. It means, that precise relaying of
474    ICMP in the real Internet is absolutely infeasible.
475  */
476         struct iphdr *iph = (struct iphdr*)skb->data;
477         const int type = icmp_hdr(skb)->type;
478         const int code = icmp_hdr(skb)->code;
479         struct ip_tunnel *t;
480         int err;
481
482         switch (type) {
483         default:
484         case ICMP_PARAMETERPROB:
485                 return 0;
486
487         case ICMP_DEST_UNREACH:
488                 switch (code) {
489                 case ICMP_SR_FAILED:
490                 case ICMP_PORT_UNREACH:
491                         /* Impossible event. */
492                         return 0;
493                 case ICMP_FRAG_NEEDED:
494                         /* Soft state for pmtu is maintained by IP core. */
495                         return 0;
496                 default:
497                         /* All others are translated to HOST_UNREACH.
498                            rfc2003 contains "deep thoughts" about NET_UNREACH,
499                            I believe they are just ether pollution. --ANK
500                          */
501                         break;
502                 }
503                 break;
504         case ICMP_TIME_EXCEEDED:
505                 if (code != ICMP_EXC_TTL)
506                         return 0;
507                 break;
508         }
509
510         err = -ENOENT;
511
512         rcu_read_lock();
513         t = ipip6_tunnel_lookup(dev_net(skb->dev),
514                                 skb->dev,
515                                 iph->daddr,
516                                 iph->saddr);
517         if (t == NULL || t->parms.iph.daddr == 0)
518                 goto out;
519
520         err = 0;
521         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
522                 goto out;
523
524         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
525                 t->err_count++;
526         else
527                 t->err_count = 1;
528         t->err_time = jiffies;
529 out:
530         rcu_read_unlock();
531         return err;
532 }
533
534 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
535 {
536         if (INET_ECN_is_ce(iph->tos))
537                 IP6_ECN_set_ce(ipv6_hdr(skb));
538 }
539
540 static int ipip6_rcv(struct sk_buff *skb)
541 {
542         struct iphdr *iph;
543         struct ip_tunnel *tunnel;
544
545         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
546                 goto out;
547
548         iph = ip_hdr(skb);
549
550         rcu_read_lock();
551         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
552                                      iph->saddr, iph->daddr);
553         if (tunnel != NULL) {
554                 secpath_reset(skb);
555                 skb->mac_header = skb->network_header;
556                 skb_reset_network_header(skb);
557                 IPCB(skb)->flags = 0;
558                 skb->protocol = htons(ETH_P_IPV6);
559                 skb->pkt_type = PACKET_HOST;
560
561                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
562                     !isatap_chksrc(skb, iph, tunnel)) {
563                         tunnel->dev->stats.rx_errors++;
564                         rcu_read_unlock();
565                         kfree_skb(skb);
566                         return 0;
567                 }
568                 tunnel->dev->stats.rx_packets++;
569                 tunnel->dev->stats.rx_bytes += skb->len;
570                 skb->dev = tunnel->dev;
571                 skb_dst_drop(skb);
572                 nf_reset(skb);
573                 ipip6_ecn_decapsulate(iph, skb);
574                 netif_rx(skb);
575                 rcu_read_unlock();
576                 return 0;
577         }
578
579         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
580         rcu_read_unlock();
581 out:
582         kfree_skb(skb);
583         return 0;
584 }
585
586 /*
587  * Returns the embedded IPv4 address if the IPv6 address
588  * comes from 6rd / 6to4 (RFC 3056) addr space.
589  */
590 static inline
591 __be32 try_6rd(struct in6_addr *v6dst, struct ip_tunnel *tunnel)
592 {
593         __be32 dst = 0;
594
595 #ifdef CONFIG_IPV6_SIT_6RD
596         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
597                               tunnel->ip6rd.prefixlen)) {
598                 unsigned pbw0, pbi0;
599                 int pbi1;
600                 u32 d;
601
602                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
603                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
604
605                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
606                     tunnel->ip6rd.relay_prefixlen;
607
608                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
609                 if (pbi1 > 0)
610                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
611                              (32 - pbi1);
612
613                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
614         }
615 #else
616         if (v6dst->s6_addr16[0] == htons(0x2002)) {
617                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
618                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
619         }
620 #endif
621         return dst;
622 }
623
624 /*
625  *      This function assumes it is being called from dev_queue_xmit()
626  *      and that skb is filled properly by that function.
627  */
628
629 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
630                                      struct net_device *dev)
631 {
632         struct ip_tunnel *tunnel = netdev_priv(dev);
633         struct net_device_stats *stats = &dev->stats;
634         struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
635         struct iphdr  *tiph = &tunnel->parms.iph;
636         struct ipv6hdr *iph6 = ipv6_hdr(skb);
637         u8     tos = tunnel->parms.iph.tos;
638         __be16 df = tiph->frag_off;
639         struct rtable *rt;                      /* Route to the other host */
640         struct net_device *tdev;                        /* Device to other host */
641         struct iphdr  *iph;                     /* Our new IP header */
642         unsigned int max_headroom;              /* The extra header space needed */
643         __be32 dst = tiph->daddr;
644         int    mtu;
645         struct in6_addr *addr6;
646         int addr_type;
647
648         if (skb->protocol != htons(ETH_P_IPV6))
649                 goto tx_error;
650
651         /* ISATAP (RFC4214) - must come before 6to4 */
652         if (dev->priv_flags & IFF_ISATAP) {
653                 struct neighbour *neigh = NULL;
654
655                 if (skb_dst(skb))
656                         neigh = skb_dst(skb)->neighbour;
657
658                 if (neigh == NULL) {
659                         if (net_ratelimit())
660                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
661                         goto tx_error;
662                 }
663
664                 addr6 = (struct in6_addr*)&neigh->primary_key;
665                 addr_type = ipv6_addr_type(addr6);
666
667                 if ((addr_type & IPV6_ADDR_UNICAST) &&
668                      ipv6_addr_is_isatap(addr6))
669                         dst = addr6->s6_addr32[3];
670                 else
671                         goto tx_error;
672         }
673
674         if (!dst)
675                 dst = try_6rd(&iph6->daddr, tunnel);
676
677         if (!dst) {
678                 struct neighbour *neigh = NULL;
679
680                 if (skb_dst(skb))
681                         neigh = skb_dst(skb)->neighbour;
682
683                 if (neigh == NULL) {
684                         if (net_ratelimit())
685                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
686                         goto tx_error;
687                 }
688
689                 addr6 = (struct in6_addr*)&neigh->primary_key;
690                 addr_type = ipv6_addr_type(addr6);
691
692                 if (addr_type == IPV6_ADDR_ANY) {
693                         addr6 = &ipv6_hdr(skb)->daddr;
694                         addr_type = ipv6_addr_type(addr6);
695                 }
696
697                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
698                         goto tx_error_icmp;
699
700                 dst = addr6->s6_addr32[3];
701         }
702
703         {
704                 struct flowi fl = { .nl_u = { .ip4_u =
705                                               { .daddr = dst,
706                                                 .saddr = tiph->saddr,
707                                                 .tos = RT_TOS(tos) } },
708                                     .oif = tunnel->parms.link,
709                                     .proto = IPPROTO_IPV6 };
710                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
711                         stats->tx_carrier_errors++;
712                         goto tx_error_icmp;
713                 }
714         }
715         if (rt->rt_type != RTN_UNICAST) {
716                 ip_rt_put(rt);
717                 stats->tx_carrier_errors++;
718                 goto tx_error_icmp;
719         }
720         tdev = rt->u.dst.dev;
721
722         if (tdev == dev) {
723                 ip_rt_put(rt);
724                 stats->collisions++;
725                 goto tx_error;
726         }
727
728         if (df) {
729                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
730
731                 if (mtu < 68) {
732                         stats->collisions++;
733                         ip_rt_put(rt);
734                         goto tx_error;
735                 }
736
737                 if (mtu < IPV6_MIN_MTU) {
738                         mtu = IPV6_MIN_MTU;
739                         df = 0;
740                 }
741
742                 if (tunnel->parms.iph.daddr && skb_dst(skb))
743                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
744
745                 if (skb->len > mtu) {
746                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
747                         ip_rt_put(rt);
748                         goto tx_error;
749                 }
750         }
751
752         if (tunnel->err_count > 0) {
753                 if (time_before(jiffies,
754                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
755                         tunnel->err_count--;
756                         dst_link_failure(skb);
757                 } else
758                         tunnel->err_count = 0;
759         }
760
761         /*
762          * Okay, now see if we can stuff it in the buffer as-is.
763          */
764         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
765
766         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
767             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
768                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
769                 if (!new_skb) {
770                         ip_rt_put(rt);
771                         txq->tx_dropped++;
772                         dev_kfree_skb(skb);
773                         return NETDEV_TX_OK;
774                 }
775                 if (skb->sk)
776                         skb_set_owner_w(new_skb, skb->sk);
777                 dev_kfree_skb(skb);
778                 skb = new_skb;
779                 iph6 = ipv6_hdr(skb);
780         }
781
782         skb->transport_header = skb->network_header;
783         skb_push(skb, sizeof(struct iphdr));
784         skb_reset_network_header(skb);
785         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
786         IPCB(skb)->flags = 0;
787         skb_dst_drop(skb);
788         skb_dst_set(skb, &rt->u.dst);
789
790         /*
791          *      Push down and install the IPIP header.
792          */
793
794         iph                     =       ip_hdr(skb);
795         iph->version            =       4;
796         iph->ihl                =       sizeof(struct iphdr)>>2;
797         iph->frag_off           =       df;
798         iph->protocol           =       IPPROTO_IPV6;
799         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
800         iph->daddr              =       rt->rt_dst;
801         iph->saddr              =       rt->rt_src;
802
803         if ((iph->ttl = tiph->ttl) == 0)
804                 iph->ttl        =       iph6->hop_limit;
805
806         nf_reset(skb);
807
808         IPTUNNEL_XMIT();
809         return NETDEV_TX_OK;
810
811 tx_error_icmp:
812         dst_link_failure(skb);
813 tx_error:
814         stats->tx_errors++;
815         dev_kfree_skb(skb);
816         return NETDEV_TX_OK;
817 }
818
819 static void ipip6_tunnel_bind_dev(struct net_device *dev)
820 {
821         struct net_device *tdev = NULL;
822         struct ip_tunnel *tunnel;
823         struct iphdr *iph;
824
825         tunnel = netdev_priv(dev);
826         iph = &tunnel->parms.iph;
827
828         if (iph->daddr) {
829                 struct flowi fl = { .nl_u = { .ip4_u =
830                                               { .daddr = iph->daddr,
831                                                 .saddr = iph->saddr,
832                                                 .tos = RT_TOS(iph->tos) } },
833                                     .oif = tunnel->parms.link,
834                                     .proto = IPPROTO_IPV6 };
835                 struct rtable *rt;
836                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
837                         tdev = rt->u.dst.dev;
838                         ip_rt_put(rt);
839                 }
840                 dev->flags |= IFF_POINTOPOINT;
841         }
842
843         if (!tdev && tunnel->parms.link)
844                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
845
846         if (tdev) {
847                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
848                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
849                 if (dev->mtu < IPV6_MIN_MTU)
850                         dev->mtu = IPV6_MIN_MTU;
851         }
852         dev->iflink = tunnel->parms.link;
853 }
854
855 static int
856 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
857 {
858         int err = 0;
859         struct ip_tunnel_parm p;
860         struct ip_tunnel_prl prl;
861         struct ip_tunnel *t;
862         struct net *net = dev_net(dev);
863         struct sit_net *sitn = net_generic(net, sit_net_id);
864 #ifdef CONFIG_IPV6_SIT_6RD
865         struct ip_tunnel_6rd ip6rd;
866 #endif
867
868         switch (cmd) {
869         case SIOCGETTUNNEL:
870 #ifdef CONFIG_IPV6_SIT_6RD
871         case SIOCGET6RD:
872 #endif
873                 t = NULL;
874                 if (dev == sitn->fb_tunnel_dev) {
875                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
876                                 err = -EFAULT;
877                                 break;
878                         }
879                         t = ipip6_tunnel_locate(net, &p, 0);
880                 }
881                 if (t == NULL)
882                         t = netdev_priv(dev);
883
884                 err = -EFAULT;
885                 if (cmd == SIOCGETTUNNEL) {
886                         memcpy(&p, &t->parms, sizeof(p));
887                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
888                                          sizeof(p)))
889                                 goto done;
890 #ifdef CONFIG_IPV6_SIT_6RD
891                 } else {
892                         ipv6_addr_copy(&ip6rd.prefix, &t->ip6rd.prefix);
893                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
894                         ip6rd.prefixlen = t->ip6rd.prefixlen;
895                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
896                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
897                                          sizeof(ip6rd)))
898                                 goto done;
899 #endif
900                 }
901                 err = 0;
902                 break;
903
904         case SIOCADDTUNNEL:
905         case SIOCCHGTUNNEL:
906                 err = -EPERM;
907                 if (!capable(CAP_NET_ADMIN))
908                         goto done;
909
910                 err = -EFAULT;
911                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
912                         goto done;
913
914                 err = -EINVAL;
915                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
916                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
917                         goto done;
918                 if (p.iph.ttl)
919                         p.iph.frag_off |= htons(IP_DF);
920
921                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
922
923                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
924                         if (t != NULL) {
925                                 if (t->dev != dev) {
926                                         err = -EEXIST;
927                                         break;
928                                 }
929                         } else {
930                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
931                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
932                                         err = -EINVAL;
933                                         break;
934                                 }
935                                 t = netdev_priv(dev);
936                                 ipip6_tunnel_unlink(sitn, t);
937                                 t->parms.iph.saddr = p.iph.saddr;
938                                 t->parms.iph.daddr = p.iph.daddr;
939                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
940                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
941                                 ipip6_tunnel_link(sitn, t);
942                                 netdev_state_change(dev);
943                         }
944                 }
945
946                 if (t) {
947                         err = 0;
948                         if (cmd == SIOCCHGTUNNEL) {
949                                 t->parms.iph.ttl = p.iph.ttl;
950                                 t->parms.iph.tos = p.iph.tos;
951                                 if (t->parms.link != p.link) {
952                                         t->parms.link = p.link;
953                                         ipip6_tunnel_bind_dev(dev);
954                                         netdev_state_change(dev);
955                                 }
956                         }
957                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
958                                 err = -EFAULT;
959                 } else
960                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
961                 break;
962
963         case SIOCDELTUNNEL:
964                 err = -EPERM;
965                 if (!capable(CAP_NET_ADMIN))
966                         goto done;
967
968                 if (dev == sitn->fb_tunnel_dev) {
969                         err = -EFAULT;
970                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
971                                 goto done;
972                         err = -ENOENT;
973                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
974                                 goto done;
975                         err = -EPERM;
976                         if (t == netdev_priv(sitn->fb_tunnel_dev))
977                                 goto done;
978                         dev = t->dev;
979                 }
980                 unregister_netdevice(dev);
981                 err = 0;
982                 break;
983
984         case SIOCGETPRL:
985                 err = -EINVAL;
986                 if (dev == sitn->fb_tunnel_dev)
987                         goto done;
988                 err = -ENOENT;
989                 if (!(t = netdev_priv(dev)))
990                         goto done;
991                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
992                 break;
993
994         case SIOCADDPRL:
995         case SIOCDELPRL:
996         case SIOCCHGPRL:
997                 err = -EPERM;
998                 if (!capable(CAP_NET_ADMIN))
999                         goto done;
1000                 err = -EINVAL;
1001                 if (dev == sitn->fb_tunnel_dev)
1002                         goto done;
1003                 err = -EFAULT;
1004                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1005                         goto done;
1006                 err = -ENOENT;
1007                 if (!(t = netdev_priv(dev)))
1008                         goto done;
1009
1010                 switch (cmd) {
1011                 case SIOCDELPRL:
1012                         err = ipip6_tunnel_del_prl(t, &prl);
1013                         break;
1014                 case SIOCADDPRL:
1015                 case SIOCCHGPRL:
1016                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1017                         break;
1018                 }
1019                 netdev_state_change(dev);
1020                 break;
1021
1022 #ifdef CONFIG_IPV6_SIT_6RD
1023         case SIOCADD6RD:
1024         case SIOCCHG6RD:
1025         case SIOCDEL6RD:
1026                 err = -EPERM;
1027                 if (!capable(CAP_NET_ADMIN))
1028                         goto done;
1029
1030                 err = -EFAULT;
1031                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1032                                    sizeof(ip6rd)))
1033                         goto done;
1034
1035                 t = netdev_priv(dev);
1036
1037                 if (cmd != SIOCDEL6RD) {
1038                         struct in6_addr prefix;
1039                         __be32 relay_prefix;
1040
1041                         err = -EINVAL;
1042                         if (ip6rd.relay_prefixlen > 32 ||
1043                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1044                                 goto done;
1045
1046                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1047                                          ip6rd.prefixlen);
1048                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1049                                 goto done;
1050                         if (ip6rd.relay_prefixlen)
1051                                 relay_prefix = ip6rd.relay_prefix &
1052                                                htonl(0xffffffffUL <<
1053                                                      (32 - ip6rd.relay_prefixlen));
1054                         else
1055                                 relay_prefix = 0;
1056                         if (relay_prefix != ip6rd.relay_prefix)
1057                                 goto done;
1058
1059                         ipv6_addr_copy(&t->ip6rd.prefix, &prefix);
1060                         t->ip6rd.relay_prefix = relay_prefix;
1061                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1062                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1063                 } else
1064                         ipip6_tunnel_clone_6rd(dev, sitn);
1065
1066                 err = 0;
1067                 break;
1068 #endif
1069
1070         default:
1071                 err = -EINVAL;
1072         }
1073
1074 done:
1075         return err;
1076 }
1077
1078 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1079 {
1080         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1081                 return -EINVAL;
1082         dev->mtu = new_mtu;
1083         return 0;
1084 }
1085
1086 static const struct net_device_ops ipip6_netdev_ops = {
1087         .ndo_uninit     = ipip6_tunnel_uninit,
1088         .ndo_start_xmit = ipip6_tunnel_xmit,
1089         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1090         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1091 };
1092
1093 static void ipip6_tunnel_setup(struct net_device *dev)
1094 {
1095         dev->netdev_ops         = &ipip6_netdev_ops;
1096         dev->destructor         = free_netdev;
1097
1098         dev->type               = ARPHRD_SIT;
1099         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1100         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1101         dev->flags              = IFF_NOARP;
1102         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1103         dev->iflink             = 0;
1104         dev->addr_len           = 4;
1105         dev->features           |= NETIF_F_NETNS_LOCAL;
1106 }
1107
1108 static void ipip6_tunnel_init(struct net_device *dev)
1109 {
1110         struct ip_tunnel *tunnel = netdev_priv(dev);
1111
1112         tunnel->dev = dev;
1113         strcpy(tunnel->parms.name, dev->name);
1114
1115         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1116         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1117
1118         ipip6_tunnel_bind_dev(dev);
1119 }
1120
1121 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1122 {
1123         struct ip_tunnel *tunnel = netdev_priv(dev);
1124         struct iphdr *iph = &tunnel->parms.iph;
1125         struct net *net = dev_net(dev);
1126         struct sit_net *sitn = net_generic(net, sit_net_id);
1127
1128         tunnel->dev = dev;
1129         strcpy(tunnel->parms.name, dev->name);
1130
1131         iph->version            = 4;
1132         iph->protocol           = IPPROTO_IPV6;
1133         iph->ihl                = 5;
1134         iph->ttl                = 64;
1135
1136         dev_hold(dev);
1137         sitn->tunnels_wc[0]     = tunnel;
1138 }
1139
1140 static struct xfrm_tunnel sit_handler = {
1141         .handler        =       ipip6_rcv,
1142         .err_handler    =       ipip6_err,
1143         .priority       =       1,
1144 };
1145
1146 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1147 {
1148         int prio;
1149
1150         for (prio = 1; prio < 4; prio++) {
1151                 int h;
1152                 for (h = 0; h < HASH_SIZE; h++) {
1153                         struct ip_tunnel *t = sitn->tunnels[prio][h];
1154
1155                         while (t != NULL) {
1156                                 unregister_netdevice_queue(t->dev, head);
1157                                 t = t->next;
1158                         }
1159                 }
1160         }
1161 }
1162
1163 static int __net_init sit_init_net(struct net *net)
1164 {
1165         struct sit_net *sitn = net_generic(net, sit_net_id);
1166         int err;
1167
1168         sitn->tunnels[0] = sitn->tunnels_wc;
1169         sitn->tunnels[1] = sitn->tunnels_l;
1170         sitn->tunnels[2] = sitn->tunnels_r;
1171         sitn->tunnels[3] = sitn->tunnels_r_l;
1172
1173         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1174                                            ipip6_tunnel_setup);
1175         if (!sitn->fb_tunnel_dev) {
1176                 err = -ENOMEM;
1177                 goto err_alloc_dev;
1178         }
1179         dev_net_set(sitn->fb_tunnel_dev, net);
1180
1181         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1182         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1183
1184         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1185                 goto err_reg_dev;
1186
1187         return 0;
1188
1189 err_reg_dev:
1190         dev_put(sitn->fb_tunnel_dev);
1191         free_netdev(sitn->fb_tunnel_dev);
1192 err_alloc_dev:
1193         return err;
1194 }
1195
1196 static void __net_exit sit_exit_net(struct net *net)
1197 {
1198         struct sit_net *sitn = net_generic(net, sit_net_id);
1199         LIST_HEAD(list);
1200
1201         rtnl_lock();
1202         sit_destroy_tunnels(sitn, &list);
1203         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1204         unregister_netdevice_many(&list);
1205         rtnl_unlock();
1206 }
1207
1208 static struct pernet_operations sit_net_ops = {
1209         .init = sit_init_net,
1210         .exit = sit_exit_net,
1211         .id   = &sit_net_id,
1212         .size = sizeof(struct sit_net),
1213 };
1214
1215 static void __exit sit_cleanup(void)
1216 {
1217         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1218
1219         unregister_pernet_device(&sit_net_ops);
1220         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1221 }
1222
1223 static int __init sit_init(void)
1224 {
1225         int err;
1226
1227         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1228
1229         err = register_pernet_device(&sit_net_ops);
1230         if (err < 0)
1231                 return err;
1232         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1233         if (err < 0) {
1234                 unregister_pernet_device(&sit_net_ops);
1235                 printk(KERN_INFO "sit init: Can't add protocol\n");
1236         }
1237         return err;
1238 }
1239
1240 module_init(sit_init);
1241 module_exit(sit_cleanup);
1242 MODULE_LICENSE("GPL");
1243 MODULE_ALIAS("sit0");