can: fix setting mcp251x bit timing on open
[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_fb_tunnel_init(struct net_device *dev);
66 static void ipip6_tunnel_init(struct net_device *dev);
67 static void ipip6_tunnel_setup(struct net_device *dev);
68
69 static int sit_net_id;
70 struct sit_net {
71         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
72         struct ip_tunnel *tunnels_r[HASH_SIZE];
73         struct ip_tunnel *tunnels_l[HASH_SIZE];
74         struct ip_tunnel *tunnels_wc[1];
75         struct ip_tunnel **tunnels[4];
76
77         struct net_device *fb_tunnel_dev;
78 };
79
80 /*
81  * Locking : hash tables are protected by RCU and a spinlock
82  */
83 static DEFINE_SPINLOCK(ipip6_lock);
84
85 #define for_each_ip_tunnel_rcu(start) \
86         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
87
88 /*
89  * Must be invoked with rcu_read_lock
90  */
91 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
92                 struct net_device *dev, __be32 remote, __be32 local)
93 {
94         unsigned h0 = HASH(remote);
95         unsigned h1 = HASH(local);
96         struct ip_tunnel *t;
97         struct sit_net *sitn = net_generic(net, sit_net_id);
98
99         for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
100                 if (local == t->parms.iph.saddr &&
101                     remote == t->parms.iph.daddr &&
102                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
103                     (t->dev->flags & IFF_UP))
104                         return t;
105         }
106         for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
107                 if (remote == t->parms.iph.daddr &&
108                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
109                     (t->dev->flags & IFF_UP))
110                         return t;
111         }
112         for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
113                 if (local == t->parms.iph.saddr &&
114                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
115                     (t->dev->flags & IFF_UP))
116                         return t;
117         }
118         t = rcu_dereference(sitn->tunnels_wc[0]);
119         if ((t != NULL) && (t->dev->flags & IFF_UP))
120                 return t;
121         return NULL;
122 }
123
124 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
125                 struct ip_tunnel_parm *parms)
126 {
127         __be32 remote = parms->iph.daddr;
128         __be32 local = parms->iph.saddr;
129         unsigned h = 0;
130         int prio = 0;
131
132         if (remote) {
133                 prio |= 2;
134                 h ^= HASH(remote);
135         }
136         if (local) {
137                 prio |= 1;
138                 h ^= HASH(local);
139         }
140         return &sitn->tunnels[prio][h];
141 }
142
143 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
144                 struct ip_tunnel *t)
145 {
146         return __ipip6_bucket(sitn, &t->parms);
147 }
148
149 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
150 {
151         struct ip_tunnel **tp;
152
153         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
154                 if (t == *tp) {
155                         spin_lock_bh(&ipip6_lock);
156                         *tp = t->next;
157                         spin_unlock_bh(&ipip6_lock);
158                         break;
159                 }
160         }
161 }
162
163 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
164 {
165         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
166
167         spin_lock_bh(&ipip6_lock);
168         t->next = *tp;
169         rcu_assign_pointer(*tp, t);
170         spin_unlock_bh(&ipip6_lock);
171 }
172
173 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
174 {
175 #ifdef CONFIG_IPV6_SIT_6RD
176         struct ip_tunnel *t = netdev_priv(dev);
177
178         if (t->dev == sitn->fb_tunnel_dev) {
179                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
180                 t->ip6rd.relay_prefix = 0;
181                 t->ip6rd.prefixlen = 16;
182                 t->ip6rd.relay_prefixlen = 0;
183         } else {
184                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
185                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
186         }
187 #endif
188 }
189
190 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
191                 struct ip_tunnel_parm *parms, int create)
192 {
193         __be32 remote = parms->iph.daddr;
194         __be32 local = parms->iph.saddr;
195         struct ip_tunnel *t, **tp, *nt;
196         struct net_device *dev;
197         char name[IFNAMSIZ];
198         struct sit_net *sitn = net_generic(net, sit_net_id);
199
200         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
201                 if (local == t->parms.iph.saddr &&
202                     remote == t->parms.iph.daddr &&
203                     parms->link == t->parms.link) {
204                         if (create)
205                                 return NULL;
206                         else
207                                 return t;
208                 }
209         }
210         if (!create)
211                 goto failed;
212
213         if (parms->name[0])
214                 strlcpy(name, parms->name, IFNAMSIZ);
215         else
216                 sprintf(name, "sit%%d");
217
218         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
219         if (dev == NULL)
220                 return NULL;
221
222         dev_net_set(dev, net);
223
224         if (strchr(name, '%')) {
225                 if (dev_alloc_name(dev, name) < 0)
226                         goto failed_free;
227         }
228
229         nt = netdev_priv(dev);
230
231         nt->parms = *parms;
232         ipip6_tunnel_init(dev);
233         ipip6_tunnel_clone_6rd(dev, sitn);
234
235         if (parms->i_flags & SIT_ISATAP)
236                 dev->priv_flags |= IFF_ISATAP;
237
238         if (register_netdevice(dev) < 0)
239                 goto failed_free;
240
241         dev_hold(dev);
242
243         ipip6_tunnel_link(sitn, nt);
244         return nt;
245
246 failed_free:
247         free_netdev(dev);
248 failed:
249         return NULL;
250 }
251
252 static DEFINE_SPINLOCK(ipip6_prl_lock);
253
254 #define for_each_prl_rcu(start)                 \
255         for (prl = rcu_dereference(start);      \
256              prl;                               \
257              prl = rcu_dereference(prl->next))
258
259 static struct ip_tunnel_prl_entry *
260 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
261 {
262         struct ip_tunnel_prl_entry *prl;
263
264         for_each_prl_rcu(t->prl)
265                 if (prl->addr == addr)
266                         break;
267         return prl;
268
269 }
270
271 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
272                                 struct ip_tunnel_prl __user *a)
273 {
274         struct ip_tunnel_prl kprl, *kp;
275         struct ip_tunnel_prl_entry *prl;
276         unsigned int cmax, c = 0, ca, len;
277         int ret = 0;
278
279         if (copy_from_user(&kprl, a, sizeof(kprl)))
280                 return -EFAULT;
281         cmax = kprl.datalen / sizeof(kprl);
282         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
283                 cmax = 1;
284
285         /* For simple GET or for root users,
286          * we try harder to allocate.
287          */
288         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
289                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
290                 NULL;
291
292         rcu_read_lock();
293
294         ca = t->prl_count < cmax ? t->prl_count : cmax;
295
296         if (!kp) {
297                 /* We don't try hard to allocate much memory for
298                  * non-root users.
299                  * For root users, retry allocating enough memory for
300                  * the answer.
301                  */
302                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
303                 if (!kp) {
304                         ret = -ENOMEM;
305                         goto out;
306                 }
307         }
308
309         c = 0;
310         for_each_prl_rcu(t->prl) {
311                 if (c >= cmax)
312                         break;
313                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
314                         continue;
315                 kp[c].addr = prl->addr;
316                 kp[c].flags = prl->flags;
317                 c++;
318                 if (kprl.addr != htonl(INADDR_ANY))
319                         break;
320         }
321 out:
322         rcu_read_unlock();
323
324         len = sizeof(*kp) * c;
325         ret = 0;
326         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
327                 ret = -EFAULT;
328
329         kfree(kp);
330
331         return ret;
332 }
333
334 static int
335 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
336 {
337         struct ip_tunnel_prl_entry *p;
338         int err = 0;
339
340         if (a->addr == htonl(INADDR_ANY))
341                 return -EINVAL;
342
343         spin_lock(&ipip6_prl_lock);
344
345         for (p = t->prl; p; p = p->next) {
346                 if (p->addr == a->addr) {
347                         if (chg) {
348                                 p->flags = a->flags;
349                                 goto out;
350                         }
351                         err = -EEXIST;
352                         goto out;
353                 }
354         }
355
356         if (chg) {
357                 err = -ENXIO;
358                 goto out;
359         }
360
361         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
362         if (!p) {
363                 err = -ENOBUFS;
364                 goto out;
365         }
366
367         INIT_RCU_HEAD(&p->rcu_head);
368         p->next = t->prl;
369         p->addr = a->addr;
370         p->flags = a->flags;
371         t->prl_count++;
372         rcu_assign_pointer(t->prl, p);
373 out:
374         spin_unlock(&ipip6_prl_lock);
375         return err;
376 }
377
378 static void prl_entry_destroy_rcu(struct rcu_head *head)
379 {
380         kfree(container_of(head, struct ip_tunnel_prl_entry, rcu_head));
381 }
382
383 static void prl_list_destroy_rcu(struct rcu_head *head)
384 {
385         struct ip_tunnel_prl_entry *p, *n;
386
387         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
388         do {
389                 n = p->next;
390                 kfree(p);
391                 p = n;
392         } while (p);
393 }
394
395 static int
396 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
397 {
398         struct ip_tunnel_prl_entry *x, **p;
399         int err = 0;
400
401         spin_lock(&ipip6_prl_lock);
402
403         if (a && a->addr != htonl(INADDR_ANY)) {
404                 for (p = &t->prl; *p; p = &(*p)->next) {
405                         if ((*p)->addr == a->addr) {
406                                 x = *p;
407                                 *p = x->next;
408                                 call_rcu(&x->rcu_head, prl_entry_destroy_rcu);
409                                 t->prl_count--;
410                                 goto out;
411                         }
412                 }
413                 err = -ENXIO;
414         } else {
415                 if (t->prl) {
416                         t->prl_count = 0;
417                         x = t->prl;
418                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
419                         t->prl = NULL;
420                 }
421         }
422 out:
423         spin_unlock(&ipip6_prl_lock);
424         return err;
425 }
426
427 static int
428 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
429 {
430         struct ip_tunnel_prl_entry *p;
431         int ok = 1;
432
433         rcu_read_lock();
434         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
435         if (p) {
436                 if (p->flags & PRL_DEFAULT)
437                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
438                 else
439                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
440         } else {
441                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
442                 if (ipv6_addr_is_isatap(addr6) &&
443                     (addr6->s6_addr32[3] == iph->saddr) &&
444                     ipv6_chk_prefix(addr6, t->dev))
445                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
446                 else
447                         ok = 0;
448         }
449         rcu_read_unlock();
450         return ok;
451 }
452
453 static void ipip6_tunnel_uninit(struct net_device *dev)
454 {
455         struct net *net = dev_net(dev);
456         struct sit_net *sitn = net_generic(net, sit_net_id);
457
458         if (dev == sitn->fb_tunnel_dev) {
459                 spin_lock_bh(&ipip6_lock);
460                 sitn->tunnels_wc[0] = NULL;
461                 spin_unlock_bh(&ipip6_lock);
462                 dev_put(dev);
463         } else {
464                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
465                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
466                 dev_put(dev);
467         }
468 }
469
470
471 static int ipip6_err(struct sk_buff *skb, u32 info)
472 {
473
474 /* All the routers (except for Linux) return only
475    8 bytes of packet payload. It means, that precise relaying of
476    ICMP in the real Internet is absolutely infeasible.
477  */
478         struct iphdr *iph = (struct iphdr*)skb->data;
479         const int type = icmp_hdr(skb)->type;
480         const int code = icmp_hdr(skb)->code;
481         struct ip_tunnel *t;
482         int err;
483
484         switch (type) {
485         default:
486         case ICMP_PARAMETERPROB:
487                 return 0;
488
489         case ICMP_DEST_UNREACH:
490                 switch (code) {
491                 case ICMP_SR_FAILED:
492                 case ICMP_PORT_UNREACH:
493                         /* Impossible event. */
494                         return 0;
495                 case ICMP_FRAG_NEEDED:
496                         /* Soft state for pmtu is maintained by IP core. */
497                         return 0;
498                 default:
499                         /* All others are translated to HOST_UNREACH.
500                            rfc2003 contains "deep thoughts" about NET_UNREACH,
501                            I believe they are just ether pollution. --ANK
502                          */
503                         break;
504                 }
505                 break;
506         case ICMP_TIME_EXCEEDED:
507                 if (code != ICMP_EXC_TTL)
508                         return 0;
509                 break;
510         }
511
512         err = -ENOENT;
513
514         rcu_read_lock();
515         t = ipip6_tunnel_lookup(dev_net(skb->dev),
516                                 skb->dev,
517                                 iph->daddr,
518                                 iph->saddr);
519         if (t == NULL || t->parms.iph.daddr == 0)
520                 goto out;
521
522         err = 0;
523         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
524                 goto out;
525
526         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
527                 t->err_count++;
528         else
529                 t->err_count = 1;
530         t->err_time = jiffies;
531 out:
532         rcu_read_unlock();
533         return err;
534 }
535
536 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
537 {
538         if (INET_ECN_is_ce(iph->tos))
539                 IP6_ECN_set_ce(ipv6_hdr(skb));
540 }
541
542 static int ipip6_rcv(struct sk_buff *skb)
543 {
544         struct iphdr *iph;
545         struct ip_tunnel *tunnel;
546
547         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
548                 goto out;
549
550         iph = ip_hdr(skb);
551
552         rcu_read_lock();
553         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
554                                      iph->saddr, iph->daddr);
555         if (tunnel != NULL) {
556                 secpath_reset(skb);
557                 skb->mac_header = skb->network_header;
558                 skb_reset_network_header(skb);
559                 IPCB(skb)->flags = 0;
560                 skb->protocol = htons(ETH_P_IPV6);
561                 skb->pkt_type = PACKET_HOST;
562
563                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
564                     !isatap_chksrc(skb, iph, tunnel)) {
565                         tunnel->dev->stats.rx_errors++;
566                         rcu_read_unlock();
567                         kfree_skb(skb);
568                         return 0;
569                 }
570                 tunnel->dev->stats.rx_packets++;
571                 tunnel->dev->stats.rx_bytes += skb->len;
572                 skb->dev = tunnel->dev;
573                 skb_dst_drop(skb);
574                 nf_reset(skb);
575                 ipip6_ecn_decapsulate(iph, skb);
576                 netif_rx(skb);
577                 rcu_read_unlock();
578                 return 0;
579         }
580
581         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
582         rcu_read_unlock();
583 out:
584         kfree_skb(skb);
585         return 0;
586 }
587
588 /*
589  * Returns the embedded IPv4 address if the IPv6 address
590  * comes from 6rd / 6to4 (RFC 3056) addr space.
591  */
592 static inline
593 __be32 try_6rd(struct in6_addr *v6dst, struct ip_tunnel *tunnel)
594 {
595         __be32 dst = 0;
596
597 #ifdef CONFIG_IPV6_SIT_6RD
598         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
599                               tunnel->ip6rd.prefixlen)) {
600                 unsigned pbw0, pbi0;
601                 int pbi1;
602                 u32 d;
603
604                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
605                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
606
607                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
608                     tunnel->ip6rd.relay_prefixlen;
609
610                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
611                 if (pbi1 > 0)
612                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
613                              (32 - pbi1);
614
615                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
616         }
617 #else
618         if (v6dst->s6_addr16[0] == htons(0x2002)) {
619                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
620                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
621         }
622 #endif
623         return dst;
624 }
625
626 /*
627  *      This function assumes it is being called from dev_queue_xmit()
628  *      and that skb is filled properly by that function.
629  */
630
631 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
632                                      struct net_device *dev)
633 {
634         struct ip_tunnel *tunnel = netdev_priv(dev);
635         struct net_device_stats *stats = &dev->stats;
636         struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
637         struct iphdr  *tiph = &tunnel->parms.iph;
638         struct ipv6hdr *iph6 = ipv6_hdr(skb);
639         u8     tos = tunnel->parms.iph.tos;
640         __be16 df = tiph->frag_off;
641         struct rtable *rt;                      /* Route to the other host */
642         struct net_device *tdev;                        /* Device to other host */
643         struct iphdr  *iph;                     /* Our new IP header */
644         unsigned int max_headroom;              /* The extra header space needed */
645         __be32 dst = tiph->daddr;
646         int    mtu;
647         struct in6_addr *addr6;
648         int addr_type;
649
650         if (skb->protocol != htons(ETH_P_IPV6))
651                 goto tx_error;
652
653         /* ISATAP (RFC4214) - must come before 6to4 */
654         if (dev->priv_flags & IFF_ISATAP) {
655                 struct neighbour *neigh = NULL;
656
657                 if (skb_dst(skb))
658                         neigh = skb_dst(skb)->neighbour;
659
660                 if (neigh == NULL) {
661                         if (net_ratelimit())
662                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
663                         goto tx_error;
664                 }
665
666                 addr6 = (struct in6_addr*)&neigh->primary_key;
667                 addr_type = ipv6_addr_type(addr6);
668
669                 if ((addr_type & IPV6_ADDR_UNICAST) &&
670                      ipv6_addr_is_isatap(addr6))
671                         dst = addr6->s6_addr32[3];
672                 else
673                         goto tx_error;
674         }
675
676         if (!dst)
677                 dst = try_6rd(&iph6->daddr, tunnel);
678
679         if (!dst) {
680                 struct neighbour *neigh = NULL;
681
682                 if (skb_dst(skb))
683                         neigh = skb_dst(skb)->neighbour;
684
685                 if (neigh == NULL) {
686                         if (net_ratelimit())
687                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
688                         goto tx_error;
689                 }
690
691                 addr6 = (struct in6_addr*)&neigh->primary_key;
692                 addr_type = ipv6_addr_type(addr6);
693
694                 if (addr_type == IPV6_ADDR_ANY) {
695                         addr6 = &ipv6_hdr(skb)->daddr;
696                         addr_type = ipv6_addr_type(addr6);
697                 }
698
699                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
700                         goto tx_error_icmp;
701
702                 dst = addr6->s6_addr32[3];
703         }
704
705         {
706                 struct flowi fl = { .nl_u = { .ip4_u =
707                                               { .daddr = dst,
708                                                 .saddr = tiph->saddr,
709                                                 .tos = RT_TOS(tos) } },
710                                     .oif = tunnel->parms.link,
711                                     .proto = IPPROTO_IPV6 };
712                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
713                         stats->tx_carrier_errors++;
714                         goto tx_error_icmp;
715                 }
716         }
717         if (rt->rt_type != RTN_UNICAST) {
718                 ip_rt_put(rt);
719                 stats->tx_carrier_errors++;
720                 goto tx_error_icmp;
721         }
722         tdev = rt->u.dst.dev;
723
724         if (tdev == dev) {
725                 ip_rt_put(rt);
726                 stats->collisions++;
727                 goto tx_error;
728         }
729
730         if (df) {
731                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
732
733                 if (mtu < 68) {
734                         stats->collisions++;
735                         ip_rt_put(rt);
736                         goto tx_error;
737                 }
738
739                 if (mtu < IPV6_MIN_MTU) {
740                         mtu = IPV6_MIN_MTU;
741                         df = 0;
742                 }
743
744                 if (tunnel->parms.iph.daddr && skb_dst(skb))
745                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
746
747                 if (skb->len > mtu) {
748                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
749                         ip_rt_put(rt);
750                         goto tx_error;
751                 }
752         }
753
754         if (tunnel->err_count > 0) {
755                 if (time_before(jiffies,
756                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
757                         tunnel->err_count--;
758                         dst_link_failure(skb);
759                 } else
760                         tunnel->err_count = 0;
761         }
762
763         /*
764          * Okay, now see if we can stuff it in the buffer as-is.
765          */
766         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
767
768         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
769             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
770                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
771                 if (!new_skb) {
772                         ip_rt_put(rt);
773                         txq->tx_dropped++;
774                         dev_kfree_skb(skb);
775                         return NETDEV_TX_OK;
776                 }
777                 if (skb->sk)
778                         skb_set_owner_w(new_skb, skb->sk);
779                 dev_kfree_skb(skb);
780                 skb = new_skb;
781                 iph6 = ipv6_hdr(skb);
782         }
783
784         skb->transport_header = skb->network_header;
785         skb_push(skb, sizeof(struct iphdr));
786         skb_reset_network_header(skb);
787         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
788         IPCB(skb)->flags = 0;
789         skb_dst_drop(skb);
790         skb_dst_set(skb, &rt->u.dst);
791
792         /*
793          *      Push down and install the IPIP header.
794          */
795
796         iph                     =       ip_hdr(skb);
797         iph->version            =       4;
798         iph->ihl                =       sizeof(struct iphdr)>>2;
799         iph->frag_off           =       df;
800         iph->protocol           =       IPPROTO_IPV6;
801         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
802         iph->daddr              =       rt->rt_dst;
803         iph->saddr              =       rt->rt_src;
804
805         if ((iph->ttl = tiph->ttl) == 0)
806                 iph->ttl        =       iph6->hop_limit;
807
808         nf_reset(skb);
809
810         IPTUNNEL_XMIT();
811         return NETDEV_TX_OK;
812
813 tx_error_icmp:
814         dst_link_failure(skb);
815 tx_error:
816         stats->tx_errors++;
817         dev_kfree_skb(skb);
818         return NETDEV_TX_OK;
819 }
820
821 static void ipip6_tunnel_bind_dev(struct net_device *dev)
822 {
823         struct net_device *tdev = NULL;
824         struct ip_tunnel *tunnel;
825         struct iphdr *iph;
826
827         tunnel = netdev_priv(dev);
828         iph = &tunnel->parms.iph;
829
830         if (iph->daddr) {
831                 struct flowi fl = { .nl_u = { .ip4_u =
832                                               { .daddr = iph->daddr,
833                                                 .saddr = iph->saddr,
834                                                 .tos = RT_TOS(iph->tos) } },
835                                     .oif = tunnel->parms.link,
836                                     .proto = IPPROTO_IPV6 };
837                 struct rtable *rt;
838                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
839                         tdev = rt->u.dst.dev;
840                         ip_rt_put(rt);
841                 }
842                 dev->flags |= IFF_POINTOPOINT;
843         }
844
845         if (!tdev && tunnel->parms.link)
846                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
847
848         if (tdev) {
849                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
850                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
851                 if (dev->mtu < IPV6_MIN_MTU)
852                         dev->mtu = IPV6_MIN_MTU;
853         }
854         dev->iflink = tunnel->parms.link;
855 }
856
857 static int
858 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
859 {
860         int err = 0;
861         struct ip_tunnel_parm p;
862         struct ip_tunnel_prl prl;
863         struct ip_tunnel *t;
864         struct net *net = dev_net(dev);
865         struct sit_net *sitn = net_generic(net, sit_net_id);
866 #ifdef CONFIG_IPV6_SIT_6RD
867         struct ip_tunnel_6rd ip6rd;
868 #endif
869
870         switch (cmd) {
871         case SIOCGETTUNNEL:
872 #ifdef CONFIG_IPV6_SIT_6RD
873         case SIOCGET6RD:
874 #endif
875                 t = NULL;
876                 if (dev == sitn->fb_tunnel_dev) {
877                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
878                                 err = -EFAULT;
879                                 break;
880                         }
881                         t = ipip6_tunnel_locate(net, &p, 0);
882                 }
883                 if (t == NULL)
884                         t = netdev_priv(dev);
885
886                 err = -EFAULT;
887                 if (cmd == SIOCGETTUNNEL) {
888                         memcpy(&p, &t->parms, sizeof(p));
889                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
890                                          sizeof(p)))
891                                 goto done;
892 #ifdef CONFIG_IPV6_SIT_6RD
893                 } else {
894                         ipv6_addr_copy(&ip6rd.prefix, &t->ip6rd.prefix);
895                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
896                         ip6rd.prefixlen = t->ip6rd.prefixlen;
897                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
898                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
899                                          sizeof(ip6rd)))
900                                 goto done;
901 #endif
902                 }
903                 err = 0;
904                 break;
905
906         case SIOCADDTUNNEL:
907         case SIOCCHGTUNNEL:
908                 err = -EPERM;
909                 if (!capable(CAP_NET_ADMIN))
910                         goto done;
911
912                 err = -EFAULT;
913                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
914                         goto done;
915
916                 err = -EINVAL;
917                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
918                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
919                         goto done;
920                 if (p.iph.ttl)
921                         p.iph.frag_off |= htons(IP_DF);
922
923                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
924
925                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
926                         if (t != NULL) {
927                                 if (t->dev != dev) {
928                                         err = -EEXIST;
929                                         break;
930                                 }
931                         } else {
932                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
933                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
934                                         err = -EINVAL;
935                                         break;
936                                 }
937                                 t = netdev_priv(dev);
938                                 ipip6_tunnel_unlink(sitn, t);
939                                 t->parms.iph.saddr = p.iph.saddr;
940                                 t->parms.iph.daddr = p.iph.daddr;
941                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
942                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
943                                 ipip6_tunnel_link(sitn, t);
944                                 netdev_state_change(dev);
945                         }
946                 }
947
948                 if (t) {
949                         err = 0;
950                         if (cmd == SIOCCHGTUNNEL) {
951                                 t->parms.iph.ttl = p.iph.ttl;
952                                 t->parms.iph.tos = p.iph.tos;
953                                 if (t->parms.link != p.link) {
954                                         t->parms.link = p.link;
955                                         ipip6_tunnel_bind_dev(dev);
956                                         netdev_state_change(dev);
957                                 }
958                         }
959                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
960                                 err = -EFAULT;
961                 } else
962                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
963                 break;
964
965         case SIOCDELTUNNEL:
966                 err = -EPERM;
967                 if (!capable(CAP_NET_ADMIN))
968                         goto done;
969
970                 if (dev == sitn->fb_tunnel_dev) {
971                         err = -EFAULT;
972                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
973                                 goto done;
974                         err = -ENOENT;
975                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
976                                 goto done;
977                         err = -EPERM;
978                         if (t == netdev_priv(sitn->fb_tunnel_dev))
979                                 goto done;
980                         dev = t->dev;
981                 }
982                 unregister_netdevice(dev);
983                 err = 0;
984                 break;
985
986         case SIOCGETPRL:
987                 err = -EINVAL;
988                 if (dev == sitn->fb_tunnel_dev)
989                         goto done;
990                 err = -ENOENT;
991                 if (!(t = netdev_priv(dev)))
992                         goto done;
993                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
994                 break;
995
996         case SIOCADDPRL:
997         case SIOCDELPRL:
998         case SIOCCHGPRL:
999                 err = -EPERM;
1000                 if (!capable(CAP_NET_ADMIN))
1001                         goto done;
1002                 err = -EINVAL;
1003                 if (dev == sitn->fb_tunnel_dev)
1004                         goto done;
1005                 err = -EFAULT;
1006                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1007                         goto done;
1008                 err = -ENOENT;
1009                 if (!(t = netdev_priv(dev)))
1010                         goto done;
1011
1012                 switch (cmd) {
1013                 case SIOCDELPRL:
1014                         err = ipip6_tunnel_del_prl(t, &prl);
1015                         break;
1016                 case SIOCADDPRL:
1017                 case SIOCCHGPRL:
1018                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1019                         break;
1020                 }
1021                 netdev_state_change(dev);
1022                 break;
1023
1024 #ifdef CONFIG_IPV6_SIT_6RD
1025         case SIOCADD6RD:
1026         case SIOCCHG6RD:
1027         case SIOCDEL6RD:
1028                 err = -EPERM;
1029                 if (!capable(CAP_NET_ADMIN))
1030                         goto done;
1031
1032                 err = -EFAULT;
1033                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1034                                    sizeof(ip6rd)))
1035                         goto done;
1036
1037                 t = netdev_priv(dev);
1038
1039                 if (cmd != SIOCDEL6RD) {
1040                         struct in6_addr prefix;
1041                         __be32 relay_prefix;
1042
1043                         err = -EINVAL;
1044                         if (ip6rd.relay_prefixlen > 32 ||
1045                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1046                                 goto done;
1047
1048                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1049                                          ip6rd.prefixlen);
1050                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1051                                 goto done;
1052                         if (ip6rd.relay_prefixlen)
1053                                 relay_prefix = ip6rd.relay_prefix &
1054                                                htonl(0xffffffffUL <<
1055                                                      (32 - ip6rd.relay_prefixlen));
1056                         else
1057                                 relay_prefix = 0;
1058                         if (relay_prefix != ip6rd.relay_prefix)
1059                                 goto done;
1060
1061                         ipv6_addr_copy(&t->ip6rd.prefix, &prefix);
1062                         t->ip6rd.relay_prefix = relay_prefix;
1063                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1064                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1065                 } else
1066                         ipip6_tunnel_clone_6rd(dev, sitn);
1067
1068                 err = 0;
1069                 break;
1070 #endif
1071
1072         default:
1073                 err = -EINVAL;
1074         }
1075
1076 done:
1077         return err;
1078 }
1079
1080 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1081 {
1082         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1083                 return -EINVAL;
1084         dev->mtu = new_mtu;
1085         return 0;
1086 }
1087
1088 static const struct net_device_ops ipip6_netdev_ops = {
1089         .ndo_uninit     = ipip6_tunnel_uninit,
1090         .ndo_start_xmit = ipip6_tunnel_xmit,
1091         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1092         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1093 };
1094
1095 static void ipip6_tunnel_setup(struct net_device *dev)
1096 {
1097         dev->netdev_ops         = &ipip6_netdev_ops;
1098         dev->destructor         = free_netdev;
1099
1100         dev->type               = ARPHRD_SIT;
1101         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1102         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1103         dev->flags              = IFF_NOARP;
1104         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1105         dev->iflink             = 0;
1106         dev->addr_len           = 4;
1107         dev->features           |= NETIF_F_NETNS_LOCAL;
1108 }
1109
1110 static void ipip6_tunnel_init(struct net_device *dev)
1111 {
1112         struct ip_tunnel *tunnel = netdev_priv(dev);
1113
1114         tunnel->dev = dev;
1115         strcpy(tunnel->parms.name, dev->name);
1116
1117         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1118         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1119
1120         ipip6_tunnel_bind_dev(dev);
1121 }
1122
1123 static void ipip6_fb_tunnel_init(struct net_device *dev)
1124 {
1125         struct ip_tunnel *tunnel = netdev_priv(dev);
1126         struct iphdr *iph = &tunnel->parms.iph;
1127         struct net *net = dev_net(dev);
1128         struct sit_net *sitn = net_generic(net, sit_net_id);
1129
1130         tunnel->dev = dev;
1131         strcpy(tunnel->parms.name, dev->name);
1132
1133         iph->version            = 4;
1134         iph->protocol           = IPPROTO_IPV6;
1135         iph->ihl                = 5;
1136         iph->ttl                = 64;
1137
1138         dev_hold(dev);
1139         sitn->tunnels_wc[0]     = tunnel;
1140 }
1141
1142 static struct xfrm_tunnel sit_handler = {
1143         .handler        =       ipip6_rcv,
1144         .err_handler    =       ipip6_err,
1145         .priority       =       1,
1146 };
1147
1148 static void sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1149 {
1150         int prio;
1151
1152         for (prio = 1; prio < 4; prio++) {
1153                 int h;
1154                 for (h = 0; h < HASH_SIZE; h++) {
1155                         struct ip_tunnel *t = sitn->tunnels[prio][h];
1156
1157                         while (t != NULL) {
1158                                 unregister_netdevice_queue(t->dev, head);
1159                                 t = t->next;
1160                         }
1161                 }
1162         }
1163 }
1164
1165 static int sit_init_net(struct net *net)
1166 {
1167         int err;
1168         struct sit_net *sitn;
1169
1170         err = -ENOMEM;
1171         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1172         if (sitn == NULL)
1173                 goto err_alloc;
1174
1175         err = net_assign_generic(net, sit_net_id, sitn);
1176         if (err < 0)
1177                 goto err_assign;
1178
1179         sitn->tunnels[0] = sitn->tunnels_wc;
1180         sitn->tunnels[1] = sitn->tunnels_l;
1181         sitn->tunnels[2] = sitn->tunnels_r;
1182         sitn->tunnels[3] = sitn->tunnels_r_l;
1183
1184         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1185                                            ipip6_tunnel_setup);
1186         if (!sitn->fb_tunnel_dev) {
1187                 err = -ENOMEM;
1188                 goto err_alloc_dev;
1189         }
1190         dev_net_set(sitn->fb_tunnel_dev, net);
1191
1192         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1193         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1194
1195         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1196                 goto err_reg_dev;
1197
1198         return 0;
1199
1200 err_reg_dev:
1201         dev_put(sitn->fb_tunnel_dev);
1202         free_netdev(sitn->fb_tunnel_dev);
1203 err_alloc_dev:
1204         /* nothing */
1205 err_assign:
1206         kfree(sitn);
1207 err_alloc:
1208         return err;
1209 }
1210
1211 static void sit_exit_net(struct net *net)
1212 {
1213         struct sit_net *sitn;
1214         LIST_HEAD(list);
1215
1216         sitn = net_generic(net, sit_net_id);
1217         rtnl_lock();
1218         sit_destroy_tunnels(sitn, &list);
1219         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1220         unregister_netdevice_many(&list);
1221         rtnl_unlock();
1222         kfree(sitn);
1223 }
1224
1225 static struct pernet_operations sit_net_ops = {
1226         .init = sit_init_net,
1227         .exit = sit_exit_net,
1228 };
1229
1230 static void __exit sit_cleanup(void)
1231 {
1232         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1233
1234         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1235         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1236 }
1237
1238 static int __init sit_init(void)
1239 {
1240         int err;
1241
1242         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1243
1244         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1245                 printk(KERN_INFO "sit init: Can't add protocol\n");
1246                 return -EAGAIN;
1247         }
1248
1249         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1250         if (err < 0)
1251                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1252
1253         return err;
1254 }
1255
1256 module_init(sit_init);
1257 module_exit(sit_cleanup);
1258 MODULE_LICENSE("GPL");
1259 MODULE_ALIAS("sit0");