Revert "sit: stateless autoconf for isatap"
[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                 struct net_device *dev, __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 &&
93                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
94                     (t->dev->flags & IFF_UP))
95                         return t;
96         }
97         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
98                 if (remote == t->parms.iph.daddr &&
99                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
100                     (t->dev->flags & IFF_UP))
101                         return t;
102         }
103         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
104                 if (local == t->parms.iph.saddr &&
105                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
106                     (t->dev->flags & IFF_UP))
107                         return t;
108         }
109         t = sitn->tunnels_wc[0];
110         if ((t != NULL) && (t->dev->flags & IFF_UP))
111                 return t;
112         return NULL;
113 }
114
115 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
116                 struct ip_tunnel_parm *parms)
117 {
118         __be32 remote = parms->iph.daddr;
119         __be32 local = parms->iph.saddr;
120         unsigned h = 0;
121         int prio = 0;
122
123         if (remote) {
124                 prio |= 2;
125                 h ^= HASH(remote);
126         }
127         if (local) {
128                 prio |= 1;
129                 h ^= HASH(local);
130         }
131         return &sitn->tunnels[prio][h];
132 }
133
134 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
135                 struct ip_tunnel *t)
136 {
137         return __ipip6_bucket(sitn, &t->parms);
138 }
139
140 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
141 {
142         struct ip_tunnel **tp;
143
144         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
145                 if (t == *tp) {
146                         write_lock_bh(&ipip6_lock);
147                         *tp = t->next;
148                         write_unlock_bh(&ipip6_lock);
149                         break;
150                 }
151         }
152 }
153
154 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
155 {
156         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
157
158         t->next = *tp;
159         write_lock_bh(&ipip6_lock);
160         *tp = t;
161         write_unlock_bh(&ipip6_lock);
162 }
163
164 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
165                 struct ip_tunnel_parm *parms, int create)
166 {
167         __be32 remote = parms->iph.daddr;
168         __be32 local = parms->iph.saddr;
169         struct ip_tunnel *t, **tp, *nt;
170         struct net_device *dev;
171         char name[IFNAMSIZ];
172         struct sit_net *sitn = net_generic(net, sit_net_id);
173
174         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
175                 if (local == t->parms.iph.saddr &&
176                     remote == t->parms.iph.daddr &&
177                     parms->link == t->parms.link) {
178                         if (create)
179                                 return NULL;
180                         else
181                                 return t;
182                 }
183         }
184         if (!create)
185                 goto failed;
186
187         if (parms->name[0])
188                 strlcpy(name, parms->name, IFNAMSIZ);
189         else
190                 sprintf(name, "sit%%d");
191
192         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
193         if (dev == NULL)
194                 return NULL;
195
196         dev_net_set(dev, net);
197
198         if (strchr(name, '%')) {
199                 if (dev_alloc_name(dev, name) < 0)
200                         goto failed_free;
201         }
202
203         nt = netdev_priv(dev);
204
205         nt->parms = *parms;
206         ipip6_tunnel_init(dev);
207
208         if (parms->i_flags & SIT_ISATAP)
209                 dev->priv_flags |= IFF_ISATAP;
210
211         if (register_netdevice(dev) < 0)
212                 goto failed_free;
213
214         dev_hold(dev);
215
216         ipip6_tunnel_link(sitn, nt);
217         return nt;
218
219 failed_free:
220         free_netdev(dev);
221 failed:
222         return NULL;
223 }
224
225 static struct ip_tunnel_prl_entry *
226 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
227 {
228         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
229
230         for (p = t->prl; p; p = p->next)
231                 if (p->addr == addr)
232                         break;
233         return p;
234
235 }
236
237 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
238                                 struct ip_tunnel_prl __user *a)
239 {
240         struct ip_tunnel_prl kprl, *kp;
241         struct ip_tunnel_prl_entry *prl;
242         unsigned int cmax, c = 0, ca, len;
243         int ret = 0;
244
245         if (copy_from_user(&kprl, a, sizeof(kprl)))
246                 return -EFAULT;
247         cmax = kprl.datalen / sizeof(kprl);
248         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
249                 cmax = 1;
250
251         /* For simple GET or for root users,
252          * we try harder to allocate.
253          */
254         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
255                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
256                 NULL;
257
258         read_lock(&ipip6_lock);
259
260         ca = t->prl_count < cmax ? t->prl_count : cmax;
261
262         if (!kp) {
263                 /* We don't try hard to allocate much memory for
264                  * non-root users.
265                  * For root users, retry allocating enough memory for
266                  * the answer.
267                  */
268                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
269                 if (!kp) {
270                         ret = -ENOMEM;
271                         goto out;
272                 }
273         }
274
275         c = 0;
276         for (prl = t->prl; prl; prl = prl->next) {
277                 if (c > cmax)
278                         break;
279                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
280                         continue;
281                 kp[c].addr = prl->addr;
282                 kp[c].flags = prl->flags;
283                 c++;
284                 if (kprl.addr != htonl(INADDR_ANY))
285                         break;
286         }
287 out:
288         read_unlock(&ipip6_lock);
289
290         len = sizeof(*kp) * c;
291         ret = 0;
292         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
293                 ret = -EFAULT;
294
295         kfree(kp);
296
297         return ret;
298 }
299
300 static int
301 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
302 {
303         struct ip_tunnel_prl_entry *p;
304         int err = 0;
305
306         if (a->addr == htonl(INADDR_ANY))
307                 return -EINVAL;
308
309         write_lock(&ipip6_lock);
310
311         for (p = t->prl; p; p = p->next) {
312                 if (p->addr == a->addr) {
313                         if (chg)
314                                 goto update;
315                         err = -EEXIST;
316                         goto out;
317                 }
318         }
319
320         if (chg) {
321                 err = -ENXIO;
322                 goto out;
323         }
324
325         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
326         if (!p) {
327                 err = -ENOBUFS;
328                 goto out;
329         }
330
331         p->next = t->prl;
332         t->prl = p;
333         t->prl_count++;
334 update:
335         p->addr = a->addr;
336         p->flags = a->flags;
337 out:
338         write_unlock(&ipip6_lock);
339         return err;
340 }
341
342 static int
343 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
344 {
345         struct ip_tunnel_prl_entry *x, **p;
346         int err = 0;
347
348         write_lock(&ipip6_lock);
349
350         if (a && a->addr != htonl(INADDR_ANY)) {
351                 for (p = &t->prl; *p; p = &(*p)->next) {
352                         if ((*p)->addr == a->addr) {
353                                 x = *p;
354                                 *p = x->next;
355                                 kfree(x);
356                                 t->prl_count--;
357                                 goto out;
358                         }
359                 }
360                 err = -ENXIO;
361         } else {
362                 while (t->prl) {
363                         x = t->prl;
364                         t->prl = t->prl->next;
365                         kfree(x);
366                         t->prl_count--;
367                 }
368         }
369 out:
370         write_unlock(&ipip6_lock);
371         return err;
372 }
373
374 static int
375 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
376 {
377         struct ip_tunnel_prl_entry *p;
378         int ok = 1;
379
380         read_lock(&ipip6_lock);
381         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
382         if (p) {
383                 if (p->flags & PRL_DEFAULT)
384                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
385                 else
386                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
387         } else {
388                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
389                 if (ipv6_addr_is_isatap(addr6) &&
390                     (addr6->s6_addr32[3] == iph->saddr) &&
391                     ipv6_chk_prefix(addr6, t->dev))
392                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
393                 else
394                         ok = 0;
395         }
396         read_unlock(&ipip6_lock);
397         return ok;
398 }
399
400 static void ipip6_tunnel_uninit(struct net_device *dev)
401 {
402         struct net *net = dev_net(dev);
403         struct sit_net *sitn = net_generic(net, sit_net_id);
404
405         if (dev == sitn->fb_tunnel_dev) {
406                 write_lock_bh(&ipip6_lock);
407                 sitn->tunnels_wc[0] = NULL;
408                 write_unlock_bh(&ipip6_lock);
409                 dev_put(dev);
410         } else {
411                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
412                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
413                 dev_put(dev);
414         }
415 }
416
417
418 static int ipip6_err(struct sk_buff *skb, u32 info)
419 {
420
421 /* All the routers (except for Linux) return only
422    8 bytes of packet payload. It means, that precise relaying of
423    ICMP in the real Internet is absolutely infeasible.
424  */
425         struct iphdr *iph = (struct iphdr*)skb->data;
426         const int type = icmp_hdr(skb)->type;
427         const int code = icmp_hdr(skb)->code;
428         struct ip_tunnel *t;
429         int err;
430
431         switch (type) {
432         default:
433         case ICMP_PARAMETERPROB:
434                 return 0;
435
436         case ICMP_DEST_UNREACH:
437                 switch (code) {
438                 case ICMP_SR_FAILED:
439                 case ICMP_PORT_UNREACH:
440                         /* Impossible event. */
441                         return 0;
442                 case ICMP_FRAG_NEEDED:
443                         /* Soft state for pmtu is maintained by IP core. */
444                         return 0;
445                 default:
446                         /* All others are translated to HOST_UNREACH.
447                            rfc2003 contains "deep thoughts" about NET_UNREACH,
448                            I believe they are just ether pollution. --ANK
449                          */
450                         break;
451                 }
452                 break;
453         case ICMP_TIME_EXCEEDED:
454                 if (code != ICMP_EXC_TTL)
455                         return 0;
456                 break;
457         }
458
459         err = -ENOENT;
460
461         read_lock(&ipip6_lock);
462         t = ipip6_tunnel_lookup(dev_net(skb->dev),
463                                 skb->dev,
464                                 iph->daddr,
465                                 iph->saddr);
466         if (t == NULL || t->parms.iph.daddr == 0)
467                 goto out;
468
469         err = 0;
470         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
471                 goto out;
472
473         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
474                 t->err_count++;
475         else
476                 t->err_count = 1;
477         t->err_time = jiffies;
478 out:
479         read_unlock(&ipip6_lock);
480         return err;
481 }
482
483 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
484 {
485         if (INET_ECN_is_ce(iph->tos))
486                 IP6_ECN_set_ce(ipv6_hdr(skb));
487 }
488
489 static int ipip6_rcv(struct sk_buff *skb)
490 {
491         struct iphdr *iph;
492         struct ip_tunnel *tunnel;
493
494         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
495                 goto out;
496
497         iph = ip_hdr(skb);
498
499         read_lock(&ipip6_lock);
500         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
501                                      iph->saddr, iph->daddr);
502         if (tunnel != NULL) {
503                 secpath_reset(skb);
504                 skb->mac_header = skb->network_header;
505                 skb_reset_network_header(skb);
506                 IPCB(skb)->flags = 0;
507                 skb->protocol = htons(ETH_P_IPV6);
508                 skb->pkt_type = PACKET_HOST;
509
510                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
511                     !isatap_chksrc(skb, iph, tunnel)) {
512                         tunnel->dev->stats.rx_errors++;
513                         read_unlock(&ipip6_lock);
514                         kfree_skb(skb);
515                         return 0;
516                 }
517                 tunnel->dev->stats.rx_packets++;
518                 tunnel->dev->stats.rx_bytes += skb->len;
519                 skb->dev = tunnel->dev;
520                 skb_dst_drop(skb);
521                 nf_reset(skb);
522                 ipip6_ecn_decapsulate(iph, skb);
523                 netif_rx(skb);
524                 read_unlock(&ipip6_lock);
525                 return 0;
526         }
527
528         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
529         read_unlock(&ipip6_lock);
530 out:
531         kfree_skb(skb);
532         return 0;
533 }
534
535 /* Returns the embedded IPv4 address if the IPv6 address
536    comes from 6to4 (RFC 3056) addr space */
537
538 static inline __be32 try_6to4(struct in6_addr *v6dst)
539 {
540         __be32 dst = 0;
541
542         if (v6dst->s6_addr16[0] == htons(0x2002)) {
543                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
544                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
545         }
546         return dst;
547 }
548
549 /*
550  *      This function assumes it is being called from dev_queue_xmit()
551  *      and that skb is filled properly by that function.
552  */
553
554 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
555                                      struct net_device *dev)
556 {
557         struct ip_tunnel *tunnel = netdev_priv(dev);
558         struct net_device_stats *stats = &tunnel->dev->stats;
559         struct iphdr  *tiph = &tunnel->parms.iph;
560         struct ipv6hdr *iph6 = ipv6_hdr(skb);
561         u8     tos = tunnel->parms.iph.tos;
562         struct rtable *rt;                      /* Route to the other host */
563         struct net_device *tdev;                        /* Device to other host */
564         struct iphdr  *iph;                     /* Our new IP header */
565         unsigned int max_headroom;              /* The extra header space needed */
566         __be32 dst = tiph->daddr;
567         int    mtu;
568         struct in6_addr *addr6;
569         int addr_type;
570
571         if (skb->protocol != htons(ETH_P_IPV6))
572                 goto tx_error;
573
574         /* ISATAP (RFC4214) - must come before 6to4 */
575         if (dev->priv_flags & IFF_ISATAP) {
576                 struct neighbour *neigh = NULL;
577
578                 if (skb_dst(skb))
579                         neigh = skb_dst(skb)->neighbour;
580
581                 if (neigh == NULL) {
582                         if (net_ratelimit())
583                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
584                         goto tx_error;
585                 }
586
587                 addr6 = (struct in6_addr*)&neigh->primary_key;
588                 addr_type = ipv6_addr_type(addr6);
589
590                 if ((addr_type & IPV6_ADDR_UNICAST) &&
591                      ipv6_addr_is_isatap(addr6))
592                         dst = addr6->s6_addr32[3];
593                 else
594                         goto tx_error;
595         }
596
597         if (!dst)
598                 dst = try_6to4(&iph6->daddr);
599
600         if (!dst) {
601                 struct neighbour *neigh = NULL;
602
603                 if (skb_dst(skb))
604                         neigh = skb_dst(skb)->neighbour;
605
606                 if (neigh == NULL) {
607                         if (net_ratelimit())
608                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
609                         goto tx_error;
610                 }
611
612                 addr6 = (struct in6_addr*)&neigh->primary_key;
613                 addr_type = ipv6_addr_type(addr6);
614
615                 if (addr_type == IPV6_ADDR_ANY) {
616                         addr6 = &ipv6_hdr(skb)->daddr;
617                         addr_type = ipv6_addr_type(addr6);
618                 }
619
620                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
621                         goto tx_error_icmp;
622
623                 dst = addr6->s6_addr32[3];
624         }
625
626         {
627                 struct flowi fl = { .nl_u = { .ip4_u =
628                                               { .daddr = dst,
629                                                 .saddr = tiph->saddr,
630                                                 .tos = RT_TOS(tos) } },
631                                     .oif = tunnel->parms.link,
632                                     .proto = IPPROTO_IPV6 };
633                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
634                         stats->tx_carrier_errors++;
635                         goto tx_error_icmp;
636                 }
637         }
638         if (rt->rt_type != RTN_UNICAST) {
639                 ip_rt_put(rt);
640                 stats->tx_carrier_errors++;
641                 goto tx_error_icmp;
642         }
643         tdev = rt->u.dst.dev;
644
645         if (tdev == dev) {
646                 ip_rt_put(rt);
647                 stats->collisions++;
648                 goto tx_error;
649         }
650
651         if (tiph->frag_off)
652                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
653         else
654                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
655
656         if (mtu < 68) {
657                 stats->collisions++;
658                 ip_rt_put(rt);
659                 goto tx_error;
660         }
661         if (mtu < IPV6_MIN_MTU)
662                 mtu = IPV6_MIN_MTU;
663         if (tunnel->parms.iph.daddr && skb_dst(skb))
664                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
665
666         if (skb->len > mtu) {
667                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
668                 ip_rt_put(rt);
669                 goto tx_error;
670         }
671
672         if (tunnel->err_count > 0) {
673                 if (time_before(jiffies,
674                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
675                         tunnel->err_count--;
676                         dst_link_failure(skb);
677                 } else
678                         tunnel->err_count = 0;
679         }
680
681         /*
682          * Okay, now see if we can stuff it in the buffer as-is.
683          */
684         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
685
686         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
687             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
688                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
689                 if (!new_skb) {
690                         ip_rt_put(rt);
691                         stats->tx_dropped++;
692                         dev_kfree_skb(skb);
693                         return NETDEV_TX_OK;
694                 }
695                 if (skb->sk)
696                         skb_set_owner_w(new_skb, skb->sk);
697                 dev_kfree_skb(skb);
698                 skb = new_skb;
699                 iph6 = ipv6_hdr(skb);
700         }
701
702         skb->transport_header = skb->network_header;
703         skb_push(skb, sizeof(struct iphdr));
704         skb_reset_network_header(skb);
705         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
706         IPCB(skb)->flags = 0;
707         skb_dst_drop(skb);
708         skb_dst_set(skb, &rt->u.dst);
709
710         /*
711          *      Push down and install the IPIP header.
712          */
713
714         iph                     =       ip_hdr(skb);
715         iph->version            =       4;
716         iph->ihl                =       sizeof(struct iphdr)>>2;
717         if (mtu > IPV6_MIN_MTU)
718                 iph->frag_off   =       tiph->frag_off;
719         else
720                 iph->frag_off   =       0;
721
722         iph->protocol           =       IPPROTO_IPV6;
723         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
724         iph->daddr              =       rt->rt_dst;
725         iph->saddr              =       rt->rt_src;
726
727         if ((iph->ttl = tiph->ttl) == 0)
728                 iph->ttl        =       iph6->hop_limit;
729
730         nf_reset(skb);
731
732         IPTUNNEL_XMIT();
733         return NETDEV_TX_OK;
734
735 tx_error_icmp:
736         dst_link_failure(skb);
737 tx_error:
738         stats->tx_errors++;
739         dev_kfree_skb(skb);
740         return NETDEV_TX_OK;
741 }
742
743 static void ipip6_tunnel_bind_dev(struct net_device *dev)
744 {
745         struct net_device *tdev = NULL;
746         struct ip_tunnel *tunnel;
747         struct iphdr *iph;
748
749         tunnel = netdev_priv(dev);
750         iph = &tunnel->parms.iph;
751
752         if (iph->daddr) {
753                 struct flowi fl = { .nl_u = { .ip4_u =
754                                               { .daddr = iph->daddr,
755                                                 .saddr = iph->saddr,
756                                                 .tos = RT_TOS(iph->tos) } },
757                                     .oif = tunnel->parms.link,
758                                     .proto = IPPROTO_IPV6 };
759                 struct rtable *rt;
760                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
761                         tdev = rt->u.dst.dev;
762                         ip_rt_put(rt);
763                 }
764                 dev->flags |= IFF_POINTOPOINT;
765         }
766
767         if (!tdev && tunnel->parms.link)
768                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
769
770         if (tdev) {
771                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
772                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
773                 if (dev->mtu < IPV6_MIN_MTU)
774                         dev->mtu = IPV6_MIN_MTU;
775         }
776         dev->iflink = tunnel->parms.link;
777 }
778
779 static int
780 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
781 {
782         int err = 0;
783         struct ip_tunnel_parm p;
784         struct ip_tunnel_prl prl;
785         struct ip_tunnel *t;
786         struct net *net = dev_net(dev);
787         struct sit_net *sitn = net_generic(net, sit_net_id);
788
789         switch (cmd) {
790         case SIOCGETTUNNEL:
791                 t = NULL;
792                 if (dev == sitn->fb_tunnel_dev) {
793                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
794                                 err = -EFAULT;
795                                 break;
796                         }
797                         t = ipip6_tunnel_locate(net, &p, 0);
798                 }
799                 if (t == NULL)
800                         t = netdev_priv(dev);
801                 memcpy(&p, &t->parms, sizeof(p));
802                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
803                         err = -EFAULT;
804                 break;
805
806         case SIOCADDTUNNEL:
807         case SIOCCHGTUNNEL:
808                 err = -EPERM;
809                 if (!capable(CAP_NET_ADMIN))
810                         goto done;
811
812                 err = -EFAULT;
813                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
814                         goto done;
815
816                 err = -EINVAL;
817                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
818                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
819                         goto done;
820                 if (p.iph.ttl)
821                         p.iph.frag_off |= htons(IP_DF);
822
823                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
824
825                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
826                         if (t != NULL) {
827                                 if (t->dev != dev) {
828                                         err = -EEXIST;
829                                         break;
830                                 }
831                         } else {
832                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
833                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
834                                         err = -EINVAL;
835                                         break;
836                                 }
837                                 t = netdev_priv(dev);
838                                 ipip6_tunnel_unlink(sitn, t);
839                                 t->parms.iph.saddr = p.iph.saddr;
840                                 t->parms.iph.daddr = p.iph.daddr;
841                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
842                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
843                                 ipip6_tunnel_link(sitn, t);
844                                 netdev_state_change(dev);
845                         }
846                 }
847
848                 if (t) {
849                         err = 0;
850                         if (cmd == SIOCCHGTUNNEL) {
851                                 t->parms.iph.ttl = p.iph.ttl;
852                                 t->parms.iph.tos = p.iph.tos;
853                                 if (t->parms.link != p.link) {
854                                         t->parms.link = p.link;
855                                         ipip6_tunnel_bind_dev(dev);
856                                         netdev_state_change(dev);
857                                 }
858                         }
859                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
860                                 err = -EFAULT;
861                 } else
862                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
863                 break;
864
865         case SIOCDELTUNNEL:
866                 err = -EPERM;
867                 if (!capable(CAP_NET_ADMIN))
868                         goto done;
869
870                 if (dev == sitn->fb_tunnel_dev) {
871                         err = -EFAULT;
872                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
873                                 goto done;
874                         err = -ENOENT;
875                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
876                                 goto done;
877                         err = -EPERM;
878                         if (t == netdev_priv(sitn->fb_tunnel_dev))
879                                 goto done;
880                         dev = t->dev;
881                 }
882                 unregister_netdevice(dev);
883                 err = 0;
884                 break;
885
886         case SIOCGETPRL:
887                 err = -EINVAL;
888                 if (dev == sitn->fb_tunnel_dev)
889                         goto done;
890                 err = -ENOENT;
891                 if (!(t = netdev_priv(dev)))
892                         goto done;
893                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
894                 break;
895
896         case SIOCADDPRL:
897         case SIOCDELPRL:
898         case SIOCCHGPRL:
899                 err = -EPERM;
900                 if (!capable(CAP_NET_ADMIN))
901                         goto done;
902                 err = -EINVAL;
903                 if (dev == sitn->fb_tunnel_dev)
904                         goto done;
905                 err = -EFAULT;
906                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
907                         goto done;
908                 err = -ENOENT;
909                 if (!(t = netdev_priv(dev)))
910                         goto done;
911
912                 switch (cmd) {
913                 case SIOCDELPRL:
914                         err = ipip6_tunnel_del_prl(t, &prl);
915                         break;
916                 case SIOCADDPRL:
917                 case SIOCCHGPRL:
918                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
919                         break;
920                 }
921                 netdev_state_change(dev);
922                 break;
923
924         default:
925                 err = -EINVAL;
926         }
927
928 done:
929         return err;
930 }
931
932 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
933 {
934         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
935                 return -EINVAL;
936         dev->mtu = new_mtu;
937         return 0;
938 }
939
940 static const struct net_device_ops ipip6_netdev_ops = {
941         .ndo_uninit     = ipip6_tunnel_uninit,
942         .ndo_start_xmit = ipip6_tunnel_xmit,
943         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
944         .ndo_change_mtu = ipip6_tunnel_change_mtu,
945 };
946
947 static void ipip6_tunnel_setup(struct net_device *dev)
948 {
949         dev->netdev_ops         = &ipip6_netdev_ops;
950         dev->destructor         = free_netdev;
951
952         dev->type               = ARPHRD_SIT;
953         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
954         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
955         dev->flags              = IFF_NOARP;
956         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
957         dev->iflink             = 0;
958         dev->addr_len           = 4;
959         dev->features           |= NETIF_F_NETNS_LOCAL;
960 }
961
962 static void ipip6_tunnel_init(struct net_device *dev)
963 {
964         struct ip_tunnel *tunnel = netdev_priv(dev);
965
966         tunnel->dev = dev;
967         strcpy(tunnel->parms.name, dev->name);
968
969         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
970         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
971
972         ipip6_tunnel_bind_dev(dev);
973 }
974
975 static void ipip6_fb_tunnel_init(struct net_device *dev)
976 {
977         struct ip_tunnel *tunnel = netdev_priv(dev);
978         struct iphdr *iph = &tunnel->parms.iph;
979         struct net *net = dev_net(dev);
980         struct sit_net *sitn = net_generic(net, sit_net_id);
981
982         tunnel->dev = dev;
983         strcpy(tunnel->parms.name, dev->name);
984
985         iph->version            = 4;
986         iph->protocol           = IPPROTO_IPV6;
987         iph->ihl                = 5;
988         iph->ttl                = 64;
989
990         dev_hold(dev);
991         sitn->tunnels_wc[0]     = tunnel;
992 }
993
994 static struct xfrm_tunnel sit_handler = {
995         .handler        =       ipip6_rcv,
996         .err_handler    =       ipip6_err,
997         .priority       =       1,
998 };
999
1000 static void sit_destroy_tunnels(struct sit_net *sitn)
1001 {
1002         int prio;
1003
1004         for (prio = 1; prio < 4; prio++) {
1005                 int h;
1006                 for (h = 0; h < HASH_SIZE; h++) {
1007                         struct ip_tunnel *t;
1008                         while ((t = sitn->tunnels[prio][h]) != NULL)
1009                                 unregister_netdevice(t->dev);
1010                 }
1011         }
1012 }
1013
1014 static int sit_init_net(struct net *net)
1015 {
1016         int err;
1017         struct sit_net *sitn;
1018
1019         err = -ENOMEM;
1020         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1021         if (sitn == NULL)
1022                 goto err_alloc;
1023
1024         err = net_assign_generic(net, sit_net_id, sitn);
1025         if (err < 0)
1026                 goto err_assign;
1027
1028         sitn->tunnels[0] = sitn->tunnels_wc;
1029         sitn->tunnels[1] = sitn->tunnels_l;
1030         sitn->tunnels[2] = sitn->tunnels_r;
1031         sitn->tunnels[3] = sitn->tunnels_r_l;
1032
1033         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1034                                            ipip6_tunnel_setup);
1035         if (!sitn->fb_tunnel_dev) {
1036                 err = -ENOMEM;
1037                 goto err_alloc_dev;
1038         }
1039         dev_net_set(sitn->fb_tunnel_dev, net);
1040
1041         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1042
1043         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1044                 goto err_reg_dev;
1045
1046         return 0;
1047
1048 err_reg_dev:
1049         dev_put(sitn->fb_tunnel_dev);
1050         free_netdev(sitn->fb_tunnel_dev);
1051 err_alloc_dev:
1052         /* nothing */
1053 err_assign:
1054         kfree(sitn);
1055 err_alloc:
1056         return err;
1057 }
1058
1059 static void sit_exit_net(struct net *net)
1060 {
1061         struct sit_net *sitn;
1062
1063         sitn = net_generic(net, sit_net_id);
1064         rtnl_lock();
1065         sit_destroy_tunnels(sitn);
1066         unregister_netdevice(sitn->fb_tunnel_dev);
1067         rtnl_unlock();
1068         kfree(sitn);
1069 }
1070
1071 static struct pernet_operations sit_net_ops = {
1072         .init = sit_init_net,
1073         .exit = sit_exit_net,
1074 };
1075
1076 static void __exit sit_cleanup(void)
1077 {
1078         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1079
1080         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1081 }
1082
1083 static int __init sit_init(void)
1084 {
1085         int err;
1086
1087         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1088
1089         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1090                 printk(KERN_INFO "sit init: Can't add protocol\n");
1091                 return -EAGAIN;
1092         }
1093
1094         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1095         if (err < 0)
1096                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1097
1098         return err;
1099 }
1100
1101 module_init(sit_init);
1102 module_exit(sit_cleanup);
1103 MODULE_LICENSE("GPL");
1104 MODULE_ALIAS("sit0");