1ebf99a6776ef85f54512cd19f4f9dbe44208ac3
[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 static DEFINE_RWLOCK(ipip6_lock);
81
82 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
83                 __be32 remote, __be32 local)
84 {
85         unsigned h0 = HASH(remote);
86         unsigned h1 = HASH(local);
87         struct ip_tunnel *t;
88         struct sit_net *sitn = net_generic(net, sit_net_id);
89
90         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
91                 if (local == t->parms.iph.saddr &&
92                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
93                         return t;
94         }
95         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
96                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
97                         return t;
98         }
99         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
100                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
101                         return t;
102         }
103         if ((t = sitn->tunnels_wc[0]) != NULL && (t->dev->flags&IFF_UP))
104                 return t;
105         return NULL;
106 }
107
108 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
109                 struct ip_tunnel_parm *parms)
110 {
111         __be32 remote = parms->iph.daddr;
112         __be32 local = parms->iph.saddr;
113         unsigned h = 0;
114         int prio = 0;
115
116         if (remote) {
117                 prio |= 2;
118                 h ^= HASH(remote);
119         }
120         if (local) {
121                 prio |= 1;
122                 h ^= HASH(local);
123         }
124         return &sitn->tunnels[prio][h];
125 }
126
127 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
128                 struct ip_tunnel *t)
129 {
130         return __ipip6_bucket(sitn, &t->parms);
131 }
132
133 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
134 {
135         struct ip_tunnel **tp;
136
137         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
138                 if (t == *tp) {
139                         write_lock_bh(&ipip6_lock);
140                         *tp = t->next;
141                         write_unlock_bh(&ipip6_lock);
142                         break;
143                 }
144         }
145 }
146
147 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
148 {
149         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
150
151         t->next = *tp;
152         write_lock_bh(&ipip6_lock);
153         *tp = t;
154         write_unlock_bh(&ipip6_lock);
155 }
156
157 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
158                 struct ip_tunnel_parm *parms, int create)
159 {
160         __be32 remote = parms->iph.daddr;
161         __be32 local = parms->iph.saddr;
162         struct ip_tunnel *t, **tp, *nt;
163         struct net_device *dev;
164         char name[IFNAMSIZ];
165         struct sit_net *sitn = net_generic(net, sit_net_id);
166
167         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
168                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
169                         return t;
170         }
171         if (!create)
172                 goto failed;
173
174         if (parms->name[0])
175                 strlcpy(name, parms->name, IFNAMSIZ);
176         else
177                 sprintf(name, "sit%%d");
178
179         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
180         if (dev == NULL)
181                 return NULL;
182
183         dev_net_set(dev, net);
184
185         if (strchr(name, '%')) {
186                 if (dev_alloc_name(dev, name) < 0)
187                         goto failed_free;
188         }
189
190         nt = netdev_priv(dev);
191         ipip6_tunnel_init(dev);
192
193         nt->parms = *parms;
194
195         if (parms->i_flags & SIT_ISATAP)
196                 dev->priv_flags |= IFF_ISATAP;
197
198         if (register_netdevice(dev) < 0)
199                 goto failed_free;
200
201         dev_hold(dev);
202
203         ipip6_tunnel_link(sitn, nt);
204         return nt;
205
206 failed_free:
207         free_netdev(dev);
208 failed:
209         return NULL;
210 }
211
212 static struct ip_tunnel_prl_entry *
213 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
214 {
215         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
216
217         for (p = t->prl; p; p = p->next)
218                 if (p->addr == addr)
219                         break;
220         return p;
221
222 }
223
224 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
225                                 struct ip_tunnel_prl __user *a)
226 {
227         struct ip_tunnel_prl kprl, *kp;
228         struct ip_tunnel_prl_entry *prl;
229         unsigned int cmax, c = 0, ca, len;
230         int ret = 0;
231
232         if (copy_from_user(&kprl, a, sizeof(kprl)))
233                 return -EFAULT;
234         cmax = kprl.datalen / sizeof(kprl);
235         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
236                 cmax = 1;
237
238         /* For simple GET or for root users,
239          * we try harder to allocate.
240          */
241         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
242                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
243                 NULL;
244
245         read_lock(&ipip6_lock);
246
247         ca = t->prl_count < cmax ? t->prl_count : cmax;
248
249         if (!kp) {
250                 /* We don't try hard to allocate much memory for
251                  * non-root users.
252                  * For root users, retry allocating enough memory for
253                  * the answer.
254                  */
255                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
256                 if (!kp) {
257                         ret = -ENOMEM;
258                         goto out;
259                 }
260         }
261
262         c = 0;
263         for (prl = t->prl; prl; prl = prl->next) {
264                 if (c > cmax)
265                         break;
266                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
267                         continue;
268                 kp[c].addr = prl->addr;
269                 kp[c].flags = prl->flags;
270                 c++;
271                 if (kprl.addr != htonl(INADDR_ANY))
272                         break;
273         }
274 out:
275         read_unlock(&ipip6_lock);
276
277         len = sizeof(*kp) * c;
278         ret = 0;
279         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
280                 ret = -EFAULT;
281
282         kfree(kp);
283
284         return ret;
285 }
286
287 static int
288 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
289 {
290         struct ip_tunnel_prl_entry *p;
291         int err = 0;
292
293         if (a->addr == htonl(INADDR_ANY))
294                 return -EINVAL;
295
296         write_lock(&ipip6_lock);
297
298         for (p = t->prl; p; p = p->next) {
299                 if (p->addr == a->addr) {
300                         if (chg)
301                                 goto update;
302                         err = -EEXIST;
303                         goto out;
304                 }
305         }
306
307         if (chg) {
308                 err = -ENXIO;
309                 goto out;
310         }
311
312         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
313         if (!p) {
314                 err = -ENOBUFS;
315                 goto out;
316         }
317
318         p->next = t->prl;
319         t->prl = p;
320         t->prl_count++;
321 update:
322         p->addr = a->addr;
323         p->flags = a->flags;
324 out:
325         write_unlock(&ipip6_lock);
326         return err;
327 }
328
329 static int
330 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
331 {
332         struct ip_tunnel_prl_entry *x, **p;
333         int err = 0;
334
335         write_lock(&ipip6_lock);
336
337         if (a && a->addr != htonl(INADDR_ANY)) {
338                 for (p = &t->prl; *p; p = &(*p)->next) {
339                         if ((*p)->addr == a->addr) {
340                                 x = *p;
341                                 *p = x->next;
342                                 kfree(x);
343                                 t->prl_count--;
344                                 goto out;
345                         }
346                 }
347                 err = -ENXIO;
348         } else {
349                 while (t->prl) {
350                         x = t->prl;
351                         t->prl = t->prl->next;
352                         kfree(x);
353                         t->prl_count--;
354                 }
355         }
356 out:
357         write_unlock(&ipip6_lock);
358         return 0;
359 }
360
361 static int
362 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
363 {
364         struct ip_tunnel_prl_entry *p;
365         int ok = 1;
366
367         read_lock(&ipip6_lock);
368         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
369         if (p) {
370                 if (p->flags & PRL_DEFAULT)
371                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
372                 else
373                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
374         } else {
375                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
376                 if (ipv6_addr_is_isatap(addr6) &&
377                     (addr6->s6_addr32[3] == iph->saddr) &&
378                     ipv6_chk_prefix(addr6, t->dev))
379                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
380                 else
381                         ok = 0;
382         }
383         read_unlock(&ipip6_lock);
384         return ok;
385 }
386
387 static void ipip6_tunnel_uninit(struct net_device *dev)
388 {
389         struct net *net = dev_net(dev);
390         struct sit_net *sitn = net_generic(net, sit_net_id);
391
392         if (dev == sitn->fb_tunnel_dev) {
393                 write_lock_bh(&ipip6_lock);
394                 sitn->tunnels_wc[0] = NULL;
395                 write_unlock_bh(&ipip6_lock);
396                 dev_put(dev);
397         } else {
398                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
399                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
400                 dev_put(dev);
401         }
402 }
403
404
405 static int ipip6_err(struct sk_buff *skb, u32 info)
406 {
407
408 /* All the routers (except for Linux) return only
409    8 bytes of packet payload. It means, that precise relaying of
410    ICMP in the real Internet is absolutely infeasible.
411  */
412         struct iphdr *iph = (struct iphdr*)skb->data;
413         const int type = icmp_hdr(skb)->type;
414         const int code = icmp_hdr(skb)->code;
415         struct ip_tunnel *t;
416         int err;
417
418         switch (type) {
419         default:
420         case ICMP_PARAMETERPROB:
421                 return 0;
422
423         case ICMP_DEST_UNREACH:
424                 switch (code) {
425                 case ICMP_SR_FAILED:
426                 case ICMP_PORT_UNREACH:
427                         /* Impossible event. */
428                         return 0;
429                 case ICMP_FRAG_NEEDED:
430                         /* Soft state for pmtu is maintained by IP core. */
431                         return 0;
432                 default:
433                         /* All others are translated to HOST_UNREACH.
434                            rfc2003 contains "deep thoughts" about NET_UNREACH,
435                            I believe they are just ether pollution. --ANK
436                          */
437                         break;
438                 }
439                 break;
440         case ICMP_TIME_EXCEEDED:
441                 if (code != ICMP_EXC_TTL)
442                         return 0;
443                 break;
444         }
445
446         err = -ENOENT;
447
448         read_lock(&ipip6_lock);
449         t = ipip6_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
450         if (t == NULL || t->parms.iph.daddr == 0)
451                 goto out;
452
453         err = 0;
454         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
455                 goto out;
456
457         if (jiffies - t->err_time < IPTUNNEL_ERR_TIMEO)
458                 t->err_count++;
459         else
460                 t->err_count = 1;
461         t->err_time = jiffies;
462 out:
463         read_unlock(&ipip6_lock);
464         return err;
465 }
466
467 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
468 {
469         if (INET_ECN_is_ce(iph->tos))
470                 IP6_ECN_set_ce(ipv6_hdr(skb));
471 }
472
473 static int ipip6_rcv(struct sk_buff *skb)
474 {
475         struct iphdr *iph;
476         struct ip_tunnel *tunnel;
477
478         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
479                 goto out;
480
481         iph = ip_hdr(skb);
482
483         read_lock(&ipip6_lock);
484         if ((tunnel = ipip6_tunnel_lookup(dev_net(skb->dev),
485                                         iph->saddr, iph->daddr)) != NULL) {
486                 secpath_reset(skb);
487                 skb->mac_header = skb->network_header;
488                 skb_reset_network_header(skb);
489                 IPCB(skb)->flags = 0;
490                 skb->protocol = htons(ETH_P_IPV6);
491                 skb->pkt_type = PACKET_HOST;
492
493                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
494                     !isatap_chksrc(skb, iph, tunnel)) {
495                         tunnel->dev->stats.rx_errors++;
496                         read_unlock(&ipip6_lock);
497                         kfree_skb(skb);
498                         return 0;
499                 }
500                 tunnel->dev->stats.rx_packets++;
501                 tunnel->dev->stats.rx_bytes += skb->len;
502                 skb->dev = tunnel->dev;
503                 dst_release(skb->dst);
504                 skb->dst = NULL;
505                 nf_reset(skb);
506                 ipip6_ecn_decapsulate(iph, skb);
507                 netif_rx(skb);
508                 read_unlock(&ipip6_lock);
509                 return 0;
510         }
511
512         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
513         read_unlock(&ipip6_lock);
514 out:
515         kfree_skb(skb);
516         return 0;
517 }
518
519 /* Returns the embedded IPv4 address if the IPv6 address
520    comes from 6to4 (RFC 3056) addr space */
521
522 static inline __be32 try_6to4(struct in6_addr *v6dst)
523 {
524         __be32 dst = 0;
525
526         if (v6dst->s6_addr16[0] == htons(0x2002)) {
527                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
528                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
529         }
530         return dst;
531 }
532
533 /*
534  *      This function assumes it is being called from dev_queue_xmit()
535  *      and that skb is filled properly by that function.
536  */
537
538 static int ipip6_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
539 {
540         struct ip_tunnel *tunnel = netdev_priv(dev);
541         struct net_device_stats *stats = &tunnel->dev->stats;
542         struct iphdr  *tiph = &tunnel->parms.iph;
543         struct ipv6hdr *iph6 = ipv6_hdr(skb);
544         u8     tos = tunnel->parms.iph.tos;
545         struct rtable *rt;                      /* Route to the other host */
546         struct net_device *tdev;                        /* Device to other host */
547         struct iphdr  *iph;                     /* Our new IP header */
548         unsigned int max_headroom;              /* The extra header space needed */
549         __be32 dst = tiph->daddr;
550         int    mtu;
551         struct in6_addr *addr6;
552         int addr_type;
553
554         if (tunnel->recursion++) {
555                 stats->collisions++;
556                 goto tx_error;
557         }
558
559         if (skb->protocol != htons(ETH_P_IPV6))
560                 goto tx_error;
561
562         /* ISATAP (RFC4214) - must come before 6to4 */
563         if (dev->priv_flags & IFF_ISATAP) {
564                 struct neighbour *neigh = NULL;
565
566                 if (skb->dst)
567                         neigh = skb->dst->neighbour;
568
569                 if (neigh == NULL) {
570                         if (net_ratelimit())
571                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
572                         goto tx_error;
573                 }
574
575                 addr6 = (struct in6_addr*)&neigh->primary_key;
576                 addr_type = ipv6_addr_type(addr6);
577
578                 if ((addr_type & IPV6_ADDR_UNICAST) &&
579                      ipv6_addr_is_isatap(addr6))
580                         dst = addr6->s6_addr32[3];
581                 else
582                         goto tx_error;
583         }
584
585         if (!dst)
586                 dst = try_6to4(&iph6->daddr);
587
588         if (!dst) {
589                 struct neighbour *neigh = NULL;
590
591                 if (skb->dst)
592                         neigh = skb->dst->neighbour;
593
594                 if (neigh == NULL) {
595                         if (net_ratelimit())
596                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
597                         goto tx_error;
598                 }
599
600                 addr6 = (struct in6_addr*)&neigh->primary_key;
601                 addr_type = ipv6_addr_type(addr6);
602
603                 if (addr_type == IPV6_ADDR_ANY) {
604                         addr6 = &ipv6_hdr(skb)->daddr;
605                         addr_type = ipv6_addr_type(addr6);
606                 }
607
608                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
609                         goto tx_error_icmp;
610
611                 dst = addr6->s6_addr32[3];
612         }
613
614         {
615                 struct flowi fl = { .nl_u = { .ip4_u =
616                                               { .daddr = dst,
617                                                 .saddr = tiph->saddr,
618                                                 .tos = RT_TOS(tos) } },
619                                     .oif = tunnel->parms.link,
620                                     .proto = IPPROTO_IPV6 };
621                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
622                         stats->tx_carrier_errors++;
623                         goto tx_error_icmp;
624                 }
625         }
626         if (rt->rt_type != RTN_UNICAST) {
627                 ip_rt_put(rt);
628                 stats->tx_carrier_errors++;
629                 goto tx_error_icmp;
630         }
631         tdev = rt->u.dst.dev;
632
633         if (tdev == dev) {
634                 ip_rt_put(rt);
635                 stats->collisions++;
636                 goto tx_error;
637         }
638
639         if (tiph->frag_off)
640                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
641         else
642                 mtu = skb->dst ? dst_mtu(skb->dst) : dev->mtu;
643
644         if (mtu < 68) {
645                 stats->collisions++;
646                 ip_rt_put(rt);
647                 goto tx_error;
648         }
649         if (mtu < IPV6_MIN_MTU)
650                 mtu = IPV6_MIN_MTU;
651         if (tunnel->parms.iph.daddr && skb->dst)
652                 skb->dst->ops->update_pmtu(skb->dst, mtu);
653
654         if (skb->len > mtu) {
655                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
656                 ip_rt_put(rt);
657                 goto tx_error;
658         }
659
660         if (tunnel->err_count > 0) {
661                 if (jiffies - tunnel->err_time < IPTUNNEL_ERR_TIMEO) {
662                         tunnel->err_count--;
663                         dst_link_failure(skb);
664                 } else
665                         tunnel->err_count = 0;
666         }
667
668         /*
669          * Okay, now see if we can stuff it in the buffer as-is.
670          */
671         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
672
673         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
674             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
675                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
676                 if (!new_skb) {
677                         ip_rt_put(rt);
678                         stats->tx_dropped++;
679                         dev_kfree_skb(skb);
680                         tunnel->recursion--;
681                         return 0;
682                 }
683                 if (skb->sk)
684                         skb_set_owner_w(new_skb, skb->sk);
685                 dev_kfree_skb(skb);
686                 skb = new_skb;
687                 iph6 = ipv6_hdr(skb);
688         }
689
690         skb->transport_header = skb->network_header;
691         skb_push(skb, sizeof(struct iphdr));
692         skb_reset_network_header(skb);
693         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
694         IPCB(skb)->flags = 0;
695         dst_release(skb->dst);
696         skb->dst = &rt->u.dst;
697
698         /*
699          *      Push down and install the IPIP header.
700          */
701
702         iph                     =       ip_hdr(skb);
703         iph->version            =       4;
704         iph->ihl                =       sizeof(struct iphdr)>>2;
705         if (mtu > IPV6_MIN_MTU)
706                 iph->frag_off   =       htons(IP_DF);
707         else
708                 iph->frag_off   =       0;
709
710         iph->protocol           =       IPPROTO_IPV6;
711         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
712         iph->daddr              =       rt->rt_dst;
713         iph->saddr              =       rt->rt_src;
714
715         if ((iph->ttl = tiph->ttl) == 0)
716                 iph->ttl        =       iph6->hop_limit;
717
718         nf_reset(skb);
719
720         IPTUNNEL_XMIT();
721         tunnel->recursion--;
722         return 0;
723
724 tx_error_icmp:
725         dst_link_failure(skb);
726 tx_error:
727         stats->tx_errors++;
728         dev_kfree_skb(skb);
729         tunnel->recursion--;
730         return 0;
731 }
732
733 static void ipip6_tunnel_bind_dev(struct net_device *dev)
734 {
735         struct net_device *tdev = NULL;
736         struct ip_tunnel *tunnel;
737         struct iphdr *iph;
738
739         tunnel = netdev_priv(dev);
740         iph = &tunnel->parms.iph;
741
742         if (iph->daddr) {
743                 struct flowi fl = { .nl_u = { .ip4_u =
744                                               { .daddr = iph->daddr,
745                                                 .saddr = iph->saddr,
746                                                 .tos = RT_TOS(iph->tos) } },
747                                     .oif = tunnel->parms.link,
748                                     .proto = IPPROTO_IPV6 };
749                 struct rtable *rt;
750                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
751                         tdev = rt->u.dst.dev;
752                         ip_rt_put(rt);
753                 }
754                 dev->flags |= IFF_POINTOPOINT;
755         }
756
757         if (!tdev && tunnel->parms.link)
758                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
759
760         if (tdev) {
761                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
762                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
763                 if (dev->mtu < IPV6_MIN_MTU)
764                         dev->mtu = IPV6_MIN_MTU;
765         }
766         dev->iflink = tunnel->parms.link;
767 }
768
769 static int
770 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
771 {
772         int err = 0;
773         struct ip_tunnel_parm p;
774         struct ip_tunnel_prl prl;
775         struct ip_tunnel *t;
776         struct net *net = dev_net(dev);
777         struct sit_net *sitn = net_generic(net, sit_net_id);
778
779         switch (cmd) {
780         case SIOCGETTUNNEL:
781                 t = NULL;
782                 if (dev == sitn->fb_tunnel_dev) {
783                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
784                                 err = -EFAULT;
785                                 break;
786                         }
787                         t = ipip6_tunnel_locate(net, &p, 0);
788                 }
789                 if (t == NULL)
790                         t = netdev_priv(dev);
791                 memcpy(&p, &t->parms, sizeof(p));
792                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
793                         err = -EFAULT;
794                 break;
795
796         case SIOCADDTUNNEL:
797         case SIOCCHGTUNNEL:
798                 err = -EPERM;
799                 if (!capable(CAP_NET_ADMIN))
800                         goto done;
801
802                 err = -EFAULT;
803                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
804                         goto done;
805
806                 err = -EINVAL;
807                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
808                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
809                         goto done;
810                 if (p.iph.ttl)
811                         p.iph.frag_off |= htons(IP_DF);
812
813                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
814
815                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
816                         if (t != NULL) {
817                                 if (t->dev != dev) {
818                                         err = -EEXIST;
819                                         break;
820                                 }
821                         } else {
822                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
823                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
824                                         err = -EINVAL;
825                                         break;
826                                 }
827                                 t = netdev_priv(dev);
828                                 ipip6_tunnel_unlink(sitn, t);
829                                 t->parms.iph.saddr = p.iph.saddr;
830                                 t->parms.iph.daddr = p.iph.daddr;
831                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
832                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
833                                 ipip6_tunnel_link(sitn, t);
834                                 netdev_state_change(dev);
835                         }
836                 }
837
838                 if (t) {
839                         err = 0;
840                         if (cmd == SIOCCHGTUNNEL) {
841                                 t->parms.iph.ttl = p.iph.ttl;
842                                 t->parms.iph.tos = p.iph.tos;
843                                 if (t->parms.link != p.link) {
844                                         t->parms.link = p.link;
845                                         ipip6_tunnel_bind_dev(dev);
846                                         netdev_state_change(dev);
847                                 }
848                         }
849                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
850                                 err = -EFAULT;
851                 } else
852                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
853                 break;
854
855         case SIOCDELTUNNEL:
856                 err = -EPERM;
857                 if (!capable(CAP_NET_ADMIN))
858                         goto done;
859
860                 if (dev == sitn->fb_tunnel_dev) {
861                         err = -EFAULT;
862                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
863                                 goto done;
864                         err = -ENOENT;
865                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
866                                 goto done;
867                         err = -EPERM;
868                         if (t == netdev_priv(sitn->fb_tunnel_dev))
869                                 goto done;
870                         dev = t->dev;
871                 }
872                 unregister_netdevice(dev);
873                 err = 0;
874                 break;
875
876         case SIOCGETPRL:
877                 err = -EINVAL;
878                 if (dev == sitn->fb_tunnel_dev)
879                         goto done;
880                 err = -ENOENT;
881                 if (!(t = netdev_priv(dev)))
882                         goto done;
883                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
884                 break;
885
886         case SIOCADDPRL:
887         case SIOCDELPRL:
888         case SIOCCHGPRL:
889                 err = -EPERM;
890                 if (!capable(CAP_NET_ADMIN))
891                         goto done;
892                 err = -EINVAL;
893                 if (dev == sitn->fb_tunnel_dev)
894                         goto done;
895                 err = -EFAULT;
896                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
897                         goto done;
898                 err = -ENOENT;
899                 if (!(t = netdev_priv(dev)))
900                         goto done;
901
902                 switch (cmd) {
903                 case SIOCDELPRL:
904                         err = ipip6_tunnel_del_prl(t, &prl);
905                         break;
906                 case SIOCADDPRL:
907                 case SIOCCHGPRL:
908                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
909                         break;
910                 }
911                 netdev_state_change(dev);
912                 break;
913
914         default:
915                 err = -EINVAL;
916         }
917
918 done:
919         return err;
920 }
921
922 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
923 {
924         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
925                 return -EINVAL;
926         dev->mtu = new_mtu;
927         return 0;
928 }
929
930 static const struct net_device_ops ipip6_netdev_ops = {
931         .ndo_uninit     = ipip6_tunnel_uninit,
932         .ndo_start_xmit = ipip6_tunnel_xmit,
933         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
934         .ndo_change_mtu = ipip6_tunnel_change_mtu,
935 };
936
937 static void ipip6_tunnel_setup(struct net_device *dev)
938 {
939         dev->netdev_ops         = &ipip6_netdev_ops;
940         dev->destructor         = free_netdev;
941
942         dev->type               = ARPHRD_SIT;
943         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
944         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
945         dev->flags              = IFF_NOARP;
946         dev->iflink             = 0;
947         dev->addr_len           = 4;
948         dev->features           |= NETIF_F_NETNS_LOCAL;
949 }
950
951 static void ipip6_tunnel_init(struct net_device *dev)
952 {
953         struct ip_tunnel *tunnel = netdev_priv(dev);
954
955         tunnel->dev = dev;
956         strcpy(tunnel->parms.name, dev->name);
957
958         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
959         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
960
961         ipip6_tunnel_bind_dev(dev);
962 }
963
964 static void ipip6_fb_tunnel_init(struct net_device *dev)
965 {
966         struct ip_tunnel *tunnel = netdev_priv(dev);
967         struct iphdr *iph = &tunnel->parms.iph;
968         struct net *net = dev_net(dev);
969         struct sit_net *sitn = net_generic(net, sit_net_id);
970
971         tunnel->dev = dev;
972         strcpy(tunnel->parms.name, dev->name);
973
974         iph->version            = 4;
975         iph->protocol           = IPPROTO_IPV6;
976         iph->ihl                = 5;
977         iph->ttl                = 64;
978
979         dev_hold(dev);
980         sitn->tunnels_wc[0]     = tunnel;
981 }
982
983 static struct xfrm_tunnel sit_handler = {
984         .handler        =       ipip6_rcv,
985         .err_handler    =       ipip6_err,
986         .priority       =       1,
987 };
988
989 static void sit_destroy_tunnels(struct sit_net *sitn)
990 {
991         int prio;
992
993         for (prio = 1; prio < 4; prio++) {
994                 int h;
995                 for (h = 0; h < HASH_SIZE; h++) {
996                         struct ip_tunnel *t;
997                         while ((t = sitn->tunnels[prio][h]) != NULL)
998                                 unregister_netdevice(t->dev);
999                 }
1000         }
1001 }
1002
1003 static int sit_init_net(struct net *net)
1004 {
1005         int err;
1006         struct sit_net *sitn;
1007
1008         err = -ENOMEM;
1009         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1010         if (sitn == NULL)
1011                 goto err_alloc;
1012
1013         err = net_assign_generic(net, sit_net_id, sitn);
1014         if (err < 0)
1015                 goto err_assign;
1016
1017         sitn->tunnels[0] = sitn->tunnels_wc;
1018         sitn->tunnels[1] = sitn->tunnels_l;
1019         sitn->tunnels[2] = sitn->tunnels_r;
1020         sitn->tunnels[3] = sitn->tunnels_r_l;
1021
1022         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1023                                            ipip6_tunnel_setup);
1024         if (!sitn->fb_tunnel_dev) {
1025                 err = -ENOMEM;
1026                 goto err_alloc_dev;
1027         }
1028
1029         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1030         dev_net_set(sitn->fb_tunnel_dev, net);
1031
1032         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1033                 goto err_reg_dev;
1034
1035         return 0;
1036
1037 err_reg_dev:
1038         dev_put(sitn->fb_tunnel_dev);
1039         free_netdev(sitn->fb_tunnel_dev);
1040 err_alloc_dev:
1041         /* nothing */
1042 err_assign:
1043         kfree(sitn);
1044 err_alloc:
1045         return err;
1046 }
1047
1048 static void sit_exit_net(struct net *net)
1049 {
1050         struct sit_net *sitn;
1051
1052         sitn = net_generic(net, sit_net_id);
1053         rtnl_lock();
1054         sit_destroy_tunnels(sitn);
1055         unregister_netdevice(sitn->fb_tunnel_dev);
1056         rtnl_unlock();
1057         kfree(sitn);
1058 }
1059
1060 static struct pernet_operations sit_net_ops = {
1061         .init = sit_init_net,
1062         .exit = sit_exit_net,
1063 };
1064
1065 static void __exit sit_cleanup(void)
1066 {
1067         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1068
1069         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1070 }
1071
1072 static int __init sit_init(void)
1073 {
1074         int err;
1075
1076         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1077
1078         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1079                 printk(KERN_INFO "sit init: Can't add protocol\n");
1080                 return -EAGAIN;
1081         }
1082
1083         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1084         if (err < 0)
1085                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1086
1087         return err;
1088 }
1089
1090 module_init(sit_init);
1091 module_exit(sit_cleanup);
1092 MODULE_LICENSE("GPL");
1093 MODULE_ALIAS("sit0");