netdev: convert pseudo-devices to netdev_tx_t
[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  * Sascha Hlusiak <mail@saschahlusiak.de>:      stateless autoconf for isatap
19  */
20
21 #include <linux/module.h>
22 #include <linux/capability.h>
23 #include <linux/errno.h>
24 #include <linux/types.h>
25 #include <linux/socket.h>
26 #include <linux/sockios.h>
27 #include <linux/net.h>
28 #include <linux/in6.h>
29 #include <linux/netdevice.h>
30 #include <linux/if_arp.h>
31 #include <linux/icmp.h>
32 #include <asm/uaccess.h>
33 #include <linux/init.h>
34 #include <linux/netfilter_ipv4.h>
35 #include <linux/if_ether.h>
36
37 #include <net/sock.h>
38 #include <net/snmp.h>
39
40 #include <net/ipv6.h>
41 #include <net/protocol.h>
42 #include <net/transp_v6.h>
43 #include <net/ip6_fib.h>
44 #include <net/ip6_route.h>
45 #include <net/ndisc.h>
46 #include <net/addrconf.h>
47 #include <net/ip.h>
48 #include <net/udp.h>
49 #include <net/icmp.h>
50 #include <net/ipip.h>
51 #include <net/inet_ecn.h>
52 #include <net/xfrm.h>
53 #include <net/dsfield.h>
54 #include <net/net_namespace.h>
55 #include <net/netns/generic.h>
56
57 /*
58    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
59
60    For comments look at net/ipv4/ip_gre.c --ANK
61  */
62
63 #define HASH_SIZE  16
64 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
65
66 static void ipip6_fb_tunnel_init(struct net_device *dev);
67 static void ipip6_tunnel_init(struct net_device *dev);
68 static void ipip6_tunnel_setup(struct net_device *dev);
69
70 static int sit_net_id;
71 struct sit_net {
72         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
73         struct ip_tunnel *tunnels_r[HASH_SIZE];
74         struct ip_tunnel *tunnels_l[HASH_SIZE];
75         struct ip_tunnel *tunnels_wc[1];
76         struct ip_tunnel **tunnels[4];
77
78         struct net_device *fb_tunnel_dev;
79 };
80
81 static DEFINE_RWLOCK(ipip6_lock);
82
83 static struct ip_tunnel * ipip6_tunnel_lookup(struct net *net,
84                 struct net_device *dev, __be32 remote, __be32 local)
85 {
86         unsigned h0 = HASH(remote);
87         unsigned h1 = HASH(local);
88         struct ip_tunnel *t;
89         struct sit_net *sitn = net_generic(net, sit_net_id);
90
91         for (t = sitn->tunnels_r_l[h0^h1]; t; t = t->next) {
92                 if (local == t->parms.iph.saddr &&
93                     remote == t->parms.iph.daddr &&
94                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
95                     (t->dev->flags & IFF_UP))
96                         return t;
97         }
98         for (t = sitn->tunnels_r[h0]; t; t = t->next) {
99                 if (remote == t->parms.iph.daddr &&
100                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
101                     (t->dev->flags & IFF_UP))
102                         return t;
103         }
104         for (t = sitn->tunnels_l[h1]; t; t = t->next) {
105                 if (local == t->parms.iph.saddr &&
106                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
107                     (t->dev->flags & IFF_UP))
108                         return t;
109         }
110         t = sitn->tunnels_wc[0];
111         if ((t != NULL) && (t->dev->flags & IFF_UP))
112                 return t;
113         return NULL;
114 }
115
116 static struct ip_tunnel **__ipip6_bucket(struct sit_net *sitn,
117                 struct ip_tunnel_parm *parms)
118 {
119         __be32 remote = parms->iph.daddr;
120         __be32 local = parms->iph.saddr;
121         unsigned h = 0;
122         int prio = 0;
123
124         if (remote) {
125                 prio |= 2;
126                 h ^= HASH(remote);
127         }
128         if (local) {
129                 prio |= 1;
130                 h ^= HASH(local);
131         }
132         return &sitn->tunnels[prio][h];
133 }
134
135 static inline struct ip_tunnel **ipip6_bucket(struct sit_net *sitn,
136                 struct ip_tunnel *t)
137 {
138         return __ipip6_bucket(sitn, &t->parms);
139 }
140
141 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
142 {
143         struct ip_tunnel **tp;
144
145         for (tp = ipip6_bucket(sitn, t); *tp; tp = &(*tp)->next) {
146                 if (t == *tp) {
147                         write_lock_bh(&ipip6_lock);
148                         *tp = t->next;
149                         write_unlock_bh(&ipip6_lock);
150                         break;
151                 }
152         }
153 }
154
155 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
156 {
157         struct ip_tunnel **tp = ipip6_bucket(sitn, t);
158
159         t->next = *tp;
160         write_lock_bh(&ipip6_lock);
161         *tp = t;
162         write_unlock_bh(&ipip6_lock);
163 }
164
165 static struct ip_tunnel * ipip6_tunnel_locate(struct net *net,
166                 struct ip_tunnel_parm *parms, int create)
167 {
168         __be32 remote = parms->iph.daddr;
169         __be32 local = parms->iph.saddr;
170         struct ip_tunnel *t, **tp, *nt;
171         struct net_device *dev;
172         char name[IFNAMSIZ];
173         struct sit_net *sitn = net_generic(net, sit_net_id);
174
175         for (tp = __ipip6_bucket(sitn, parms); (t = *tp) != NULL; tp = &t->next) {
176                 if (local == t->parms.iph.saddr &&
177                     remote == t->parms.iph.daddr &&
178                     parms->link == t->parms.link) {
179                         if (create)
180                                 return NULL;
181                         else
182                                 return t;
183                 }
184         }
185         if (!create)
186                 goto failed;
187
188         if (parms->name[0])
189                 strlcpy(name, parms->name, IFNAMSIZ);
190         else
191                 sprintf(name, "sit%%d");
192
193         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
194         if (dev == NULL)
195                 return NULL;
196
197         dev_net_set(dev, net);
198
199         if (strchr(name, '%')) {
200                 if (dev_alloc_name(dev, name) < 0)
201                         goto failed_free;
202         }
203
204         nt = netdev_priv(dev);
205
206         nt->parms = *parms;
207         ipip6_tunnel_init(dev);
208
209         if (parms->i_flags & SIT_ISATAP)
210                 dev->priv_flags |= IFF_ISATAP;
211
212         if (register_netdevice(dev) < 0)
213                 goto failed_free;
214
215         dev_hold(dev);
216
217         ipip6_tunnel_link(sitn, nt);
218         return nt;
219
220 failed_free:
221         free_netdev(dev);
222 failed:
223         return NULL;
224 }
225
226 static void ipip6_tunnel_rs_timer(unsigned long data)
227 {
228         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *) data;
229         struct inet6_dev *ifp;
230         struct inet6_ifaddr *addr;
231
232         spin_lock(&p->lock);
233         ifp = __in6_dev_get(p->tunnel->dev);
234
235         read_lock_bh(&ifp->lock);
236         for (addr = ifp->addr_list; addr; addr = addr->if_next) {
237                 struct in6_addr rtr;
238
239                 if (!(ipv6_addr_type(&addr->addr) & IPV6_ADDR_LINKLOCAL))
240                         continue;
241
242                 /* Send RS to guessed linklocal address of router
243                  *
244                  * Better: send to ff02::2 encapsuled in unicast directly
245                  * to router-v4 instead of guessing the v6 address.
246                  *
247                  * Cisco/Windows seem to not set the u/l bit correctly,
248                  * so we won't guess right.
249                  */
250                 ipv6_addr_set(&rtr,  htonl(0xFE800000), 0, 0, 0);
251                 if (!__ipv6_isatap_ifid(rtr.s6_addr + 8,
252                                         p->addr)) {
253                         ndisc_send_rs(p->tunnel->dev, &addr->addr, &rtr);
254                 }
255         }
256         read_unlock_bh(&ifp->lock);
257
258         mod_timer(&p->rs_timer, jiffies + HZ * p->rs_delay);
259         spin_unlock(&p->lock);
260
261         return;
262 }
263
264 static struct ip_tunnel_prl_entry *
265 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
266 {
267         struct ip_tunnel_prl_entry *p = (struct ip_tunnel_prl_entry *)NULL;
268
269         for (p = t->prl; p; p = p->next)
270                 if (p->addr == addr)
271                         break;
272         return p;
273
274 }
275
276 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
277                                 struct ip_tunnel_prl __user *a)
278 {
279         struct ip_tunnel_prl kprl, *kp;
280         struct ip_tunnel_prl_entry *prl;
281         unsigned int cmax, c = 0, ca, len;
282         int ret = 0;
283
284         if (copy_from_user(&kprl, a, sizeof(kprl)))
285                 return -EFAULT;
286         cmax = kprl.datalen / sizeof(kprl);
287         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
288                 cmax = 1;
289
290         /* For simple GET or for root users,
291          * we try harder to allocate.
292          */
293         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
294                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
295                 NULL;
296
297         read_lock(&ipip6_lock);
298
299         ca = t->prl_count < cmax ? t->prl_count : cmax;
300
301         if (!kp) {
302                 /* We don't try hard to allocate much memory for
303                  * non-root users.
304                  * For root users, retry allocating enough memory for
305                  * the answer.
306                  */
307                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
308                 if (!kp) {
309                         ret = -ENOMEM;
310                         goto out;
311                 }
312         }
313
314         c = 0;
315         for (prl = t->prl; prl; prl = prl->next) {
316                 if (c > cmax)
317                         break;
318                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
319                         continue;
320                 kp[c].addr = prl->addr;
321                 kp[c].flags = prl->flags;
322                 kp[c].rs_delay = prl->rs_delay;
323                 c++;
324                 if (kprl.addr != htonl(INADDR_ANY))
325                         break;
326         }
327 out:
328         read_unlock(&ipip6_lock);
329
330         len = sizeof(*kp) * c;
331         ret = 0;
332         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
333                 ret = -EFAULT;
334
335         kfree(kp);
336
337         return ret;
338 }
339
340 static int
341 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
342 {
343         struct ip_tunnel_prl_entry *p;
344         int err = 0;
345
346         if (a->addr == htonl(INADDR_ANY))
347                 return -EINVAL;
348
349         write_lock(&ipip6_lock);
350
351         for (p = t->prl; p; p = p->next) {
352                 if (p->addr == a->addr) {
353                         if (chg)
354                                 goto update;
355                         err = -EEXIST;
356                         goto out;
357                 }
358         }
359
360         if (chg) {
361                 err = -ENXIO;
362                 goto out;
363         }
364
365         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
366         if (!p) {
367                 err = -ENOBUFS;
368                 goto out;
369         }
370
371         p->next = t->prl;
372         p->tunnel = t;
373         t->prl = p;
374         t->prl_count++;
375
376         spin_lock_init(&p->lock);
377         setup_timer(&p->rs_timer, ipip6_tunnel_rs_timer, (unsigned long) p);
378 update:
379         p->addr = a->addr;
380         p->flags = a->flags;
381         p->rs_delay = a->rs_delay;
382         if (p->rs_delay == 0)
383                 p->rs_delay = IPTUNNEL_RS_DEFAULT_DELAY;
384         spin_lock(&p->lock);
385         del_timer(&p->rs_timer);
386         if (p->flags & PRL_DEFAULT)
387                 mod_timer(&p->rs_timer, jiffies + 1);
388         spin_unlock(&p->lock);
389 out:
390         write_unlock(&ipip6_lock);
391         return err;
392 }
393
394 static int
395 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
396 {
397         struct ip_tunnel_prl_entry *x, **p;
398         int err = 0;
399
400         write_lock(&ipip6_lock);
401
402         if (a && a->addr != htonl(INADDR_ANY)) {
403                 for (p = &t->prl; *p; p = &(*p)->next) {
404                         if ((*p)->addr == a->addr) {
405                                 x = *p;
406                                 *p = x->next;
407                                 spin_lock(&x->lock);
408                                 del_timer(&x->rs_timer);
409                                 spin_unlock(&x->lock);
410                                 kfree(x);
411                                 t->prl_count--;
412                                 goto out;
413                         }
414                 }
415                 err = -ENXIO;
416         } else {
417                 while (t->prl) {
418                         x = t->prl;
419                         t->prl = t->prl->next;
420                         spin_lock(&x->lock);
421                         del_timer(&x->rs_timer);
422                         spin_unlock(&x->lock);
423                         kfree(x);
424                         t->prl_count--;
425                 }
426         }
427 out:
428         write_unlock(&ipip6_lock);
429         return err;
430 }
431
432 static int
433 isatap_chksrc(struct sk_buff *skb, struct iphdr *iph, struct ip_tunnel *t)
434 {
435         struct ip_tunnel_prl_entry *p;
436         int ok = 1;
437
438         read_lock(&ipip6_lock);
439         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
440         if (p) {
441                 if (p->flags & PRL_DEFAULT)
442                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
443                 else
444                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
445         } else {
446                 struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
447                 if (ipv6_addr_is_isatap(addr6) &&
448                     (addr6->s6_addr32[3] == iph->saddr) &&
449                     ipv6_chk_prefix(addr6, t->dev))
450                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
451                 else
452                         ok = 0;
453         }
454         read_unlock(&ipip6_lock);
455         return ok;
456 }
457
458 static void ipip6_tunnel_uninit(struct net_device *dev)
459 {
460         struct net *net = dev_net(dev);
461         struct sit_net *sitn = net_generic(net, sit_net_id);
462
463         if (dev == sitn->fb_tunnel_dev) {
464                 write_lock_bh(&ipip6_lock);
465                 sitn->tunnels_wc[0] = NULL;
466                 write_unlock_bh(&ipip6_lock);
467                 dev_put(dev);
468         } else {
469                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
470                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
471                 dev_put(dev);
472         }
473 }
474
475
476 static int ipip6_err(struct sk_buff *skb, u32 info)
477 {
478
479 /* All the routers (except for Linux) return only
480    8 bytes of packet payload. It means, that precise relaying of
481    ICMP in the real Internet is absolutely infeasible.
482  */
483         struct iphdr *iph = (struct iphdr*)skb->data;
484         const int type = icmp_hdr(skb)->type;
485         const int code = icmp_hdr(skb)->code;
486         struct ip_tunnel *t;
487         int err;
488
489         switch (type) {
490         default:
491         case ICMP_PARAMETERPROB:
492                 return 0;
493
494         case ICMP_DEST_UNREACH:
495                 switch (code) {
496                 case ICMP_SR_FAILED:
497                 case ICMP_PORT_UNREACH:
498                         /* Impossible event. */
499                         return 0;
500                 case ICMP_FRAG_NEEDED:
501                         /* Soft state for pmtu is maintained by IP core. */
502                         return 0;
503                 default:
504                         /* All others are translated to HOST_UNREACH.
505                            rfc2003 contains "deep thoughts" about NET_UNREACH,
506                            I believe they are just ether pollution. --ANK
507                          */
508                         break;
509                 }
510                 break;
511         case ICMP_TIME_EXCEEDED:
512                 if (code != ICMP_EXC_TTL)
513                         return 0;
514                 break;
515         }
516
517         err = -ENOENT;
518
519         read_lock(&ipip6_lock);
520         t = ipip6_tunnel_lookup(dev_net(skb->dev),
521                                 skb->dev,
522                                 iph->daddr,
523                                 iph->saddr);
524         if (t == NULL || t->parms.iph.daddr == 0)
525                 goto out;
526
527         err = 0;
528         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
529                 goto out;
530
531         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
532                 t->err_count++;
533         else
534                 t->err_count = 1;
535         t->err_time = jiffies;
536 out:
537         read_unlock(&ipip6_lock);
538         return err;
539 }
540
541 static inline void ipip6_ecn_decapsulate(struct iphdr *iph, struct sk_buff *skb)
542 {
543         if (INET_ECN_is_ce(iph->tos))
544                 IP6_ECN_set_ce(ipv6_hdr(skb));
545 }
546
547 static int ipip6_rcv(struct sk_buff *skb)
548 {
549         struct iphdr *iph;
550         struct ip_tunnel *tunnel;
551
552         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
553                 goto out;
554
555         iph = ip_hdr(skb);
556
557         read_lock(&ipip6_lock);
558         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
559                                      iph->saddr, iph->daddr);
560         if (tunnel != NULL) {
561                 secpath_reset(skb);
562                 skb->mac_header = skb->network_header;
563                 skb_reset_network_header(skb);
564                 IPCB(skb)->flags = 0;
565                 skb->protocol = htons(ETH_P_IPV6);
566                 skb->pkt_type = PACKET_HOST;
567
568                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
569                     !isatap_chksrc(skb, iph, tunnel)) {
570                         tunnel->dev->stats.rx_errors++;
571                         read_unlock(&ipip6_lock);
572                         kfree_skb(skb);
573                         return 0;
574                 }
575                 tunnel->dev->stats.rx_packets++;
576                 tunnel->dev->stats.rx_bytes += skb->len;
577                 skb->dev = tunnel->dev;
578                 skb_dst_drop(skb);
579                 nf_reset(skb);
580                 ipip6_ecn_decapsulate(iph, skb);
581                 netif_rx(skb);
582                 read_unlock(&ipip6_lock);
583                 return 0;
584         }
585
586         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
587         read_unlock(&ipip6_lock);
588 out:
589         kfree_skb(skb);
590         return 0;
591 }
592
593 /* Returns the embedded IPv4 address if the IPv6 address
594    comes from 6to4 (RFC 3056) addr space */
595
596 static inline __be32 try_6to4(struct in6_addr *v6dst)
597 {
598         __be32 dst = 0;
599
600         if (v6dst->s6_addr16[0] == htons(0x2002)) {
601                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
602                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
603         }
604         return dst;
605 }
606
607 /*
608  *      This function assumes it is being called from dev_queue_xmit()
609  *      and that skb is filled properly by that function.
610  */
611
612 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
613                                      struct net_device *dev)
614 {
615         struct ip_tunnel *tunnel = netdev_priv(dev);
616         struct net_device_stats *stats = &tunnel->dev->stats;
617         struct iphdr  *tiph = &tunnel->parms.iph;
618         struct ipv6hdr *iph6 = ipv6_hdr(skb);
619         u8     tos = tunnel->parms.iph.tos;
620         struct rtable *rt;                      /* Route to the other host */
621         struct net_device *tdev;                        /* Device to other host */
622         struct iphdr  *iph;                     /* Our new IP header */
623         unsigned int max_headroom;              /* The extra header space needed */
624         __be32 dst = tiph->daddr;
625         int    mtu;
626         struct in6_addr *addr6;
627         int addr_type;
628
629         if (tunnel->recursion++) {
630                 stats->collisions++;
631                 goto tx_error;
632         }
633
634         if (skb->protocol != htons(ETH_P_IPV6))
635                 goto tx_error;
636
637         /* ISATAP (RFC4214) - must come before 6to4 */
638         if (dev->priv_flags & IFF_ISATAP) {
639                 struct neighbour *neigh = NULL;
640
641                 if (skb_dst(skb))
642                         neigh = skb_dst(skb)->neighbour;
643
644                 if (neigh == NULL) {
645                         if (net_ratelimit())
646                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
647                         goto tx_error;
648                 }
649
650                 addr6 = (struct in6_addr*)&neigh->primary_key;
651                 addr_type = ipv6_addr_type(addr6);
652
653                 if ((addr_type & IPV6_ADDR_UNICAST) &&
654                      ipv6_addr_is_isatap(addr6))
655                         dst = addr6->s6_addr32[3];
656                 else
657                         goto tx_error;
658         }
659
660         if (!dst)
661                 dst = try_6to4(&iph6->daddr);
662
663         if (!dst) {
664                 struct neighbour *neigh = NULL;
665
666                 if (skb_dst(skb))
667                         neigh = skb_dst(skb)->neighbour;
668
669                 if (neigh == NULL) {
670                         if (net_ratelimit())
671                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
672                         goto tx_error;
673                 }
674
675                 addr6 = (struct in6_addr*)&neigh->primary_key;
676                 addr_type = ipv6_addr_type(addr6);
677
678                 if (addr_type == IPV6_ADDR_ANY) {
679                         addr6 = &ipv6_hdr(skb)->daddr;
680                         addr_type = ipv6_addr_type(addr6);
681                 }
682
683                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
684                         goto tx_error_icmp;
685
686                 dst = addr6->s6_addr32[3];
687         }
688
689         {
690                 struct flowi fl = { .nl_u = { .ip4_u =
691                                               { .daddr = dst,
692                                                 .saddr = tiph->saddr,
693                                                 .tos = RT_TOS(tos) } },
694                                     .oif = tunnel->parms.link,
695                                     .proto = IPPROTO_IPV6 };
696                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
697                         stats->tx_carrier_errors++;
698                         goto tx_error_icmp;
699                 }
700         }
701         if (rt->rt_type != RTN_UNICAST) {
702                 ip_rt_put(rt);
703                 stats->tx_carrier_errors++;
704                 goto tx_error_icmp;
705         }
706         tdev = rt->u.dst.dev;
707
708         if (tdev == dev) {
709                 ip_rt_put(rt);
710                 stats->collisions++;
711                 goto tx_error;
712         }
713
714         if (tiph->frag_off)
715                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
716         else
717                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
718
719         if (mtu < 68) {
720                 stats->collisions++;
721                 ip_rt_put(rt);
722                 goto tx_error;
723         }
724         if (mtu < IPV6_MIN_MTU)
725                 mtu = IPV6_MIN_MTU;
726         if (tunnel->parms.iph.daddr && skb_dst(skb))
727                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
728
729         if (skb->len > mtu) {
730                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
731                 ip_rt_put(rt);
732                 goto tx_error;
733         }
734
735         if (tunnel->err_count > 0) {
736                 if (time_before(jiffies,
737                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
738                         tunnel->err_count--;
739                         dst_link_failure(skb);
740                 } else
741                         tunnel->err_count = 0;
742         }
743
744         /*
745          * Okay, now see if we can stuff it in the buffer as-is.
746          */
747         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
748
749         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
750             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
751                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
752                 if (!new_skb) {
753                         ip_rt_put(rt);
754                         stats->tx_dropped++;
755                         dev_kfree_skb(skb);
756                         tunnel->recursion--;
757                         return NETDEV_TX_OK;
758                 }
759                 if (skb->sk)
760                         skb_set_owner_w(new_skb, skb->sk);
761                 dev_kfree_skb(skb);
762                 skb = new_skb;
763                 iph6 = ipv6_hdr(skb);
764         }
765
766         skb->transport_header = skb->network_header;
767         skb_push(skb, sizeof(struct iphdr));
768         skb_reset_network_header(skb);
769         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
770         IPCB(skb)->flags = 0;
771         skb_dst_drop(skb);
772         skb_dst_set(skb, &rt->u.dst);
773
774         /*
775          *      Push down and install the IPIP header.
776          */
777
778         iph                     =       ip_hdr(skb);
779         iph->version            =       4;
780         iph->ihl                =       sizeof(struct iphdr)>>2;
781         if (mtu > IPV6_MIN_MTU)
782                 iph->frag_off   =       tiph->frag_off;
783         else
784                 iph->frag_off   =       0;
785
786         iph->protocol           =       IPPROTO_IPV6;
787         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
788         iph->daddr              =       rt->rt_dst;
789         iph->saddr              =       rt->rt_src;
790
791         if ((iph->ttl = tiph->ttl) == 0)
792                 iph->ttl        =       iph6->hop_limit;
793
794         nf_reset(skb);
795
796         IPTUNNEL_XMIT();
797         tunnel->recursion--;
798         return NETDEV_TX_OK;
799
800 tx_error_icmp:
801         dst_link_failure(skb);
802 tx_error:
803         stats->tx_errors++;
804         dev_kfree_skb(skb);
805         tunnel->recursion--;
806         return NETDEV_TX_OK;
807 }
808
809 static void ipip6_tunnel_bind_dev(struct net_device *dev)
810 {
811         struct net_device *tdev = NULL;
812         struct ip_tunnel *tunnel;
813         struct iphdr *iph;
814
815         tunnel = netdev_priv(dev);
816         iph = &tunnel->parms.iph;
817
818         if (iph->daddr) {
819                 struct flowi fl = { .nl_u = { .ip4_u =
820                                               { .daddr = iph->daddr,
821                                                 .saddr = iph->saddr,
822                                                 .tos = RT_TOS(iph->tos) } },
823                                     .oif = tunnel->parms.link,
824                                     .proto = IPPROTO_IPV6 };
825                 struct rtable *rt;
826                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
827                         tdev = rt->u.dst.dev;
828                         ip_rt_put(rt);
829                 }
830                 dev->flags |= IFF_POINTOPOINT;
831         }
832
833         if (!tdev && tunnel->parms.link)
834                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
835
836         if (tdev) {
837                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
838                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
839                 if (dev->mtu < IPV6_MIN_MTU)
840                         dev->mtu = IPV6_MIN_MTU;
841         }
842         dev->iflink = tunnel->parms.link;
843 }
844
845 static int
846 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
847 {
848         int err = 0;
849         struct ip_tunnel_parm p;
850         struct ip_tunnel_prl prl;
851         struct ip_tunnel *t;
852         struct net *net = dev_net(dev);
853         struct sit_net *sitn = net_generic(net, sit_net_id);
854
855         switch (cmd) {
856         case SIOCGETTUNNEL:
857                 t = NULL;
858                 if (dev == sitn->fb_tunnel_dev) {
859                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
860                                 err = -EFAULT;
861                                 break;
862                         }
863                         t = ipip6_tunnel_locate(net, &p, 0);
864                 }
865                 if (t == NULL)
866                         t = netdev_priv(dev);
867                 memcpy(&p, &t->parms, sizeof(p));
868                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
869                         err = -EFAULT;
870                 break;
871
872         case SIOCADDTUNNEL:
873         case SIOCCHGTUNNEL:
874                 err = -EPERM;
875                 if (!capable(CAP_NET_ADMIN))
876                         goto done;
877
878                 err = -EFAULT;
879                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
880                         goto done;
881
882                 err = -EINVAL;
883                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
884                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
885                         goto done;
886                 if (p.iph.ttl)
887                         p.iph.frag_off |= htons(IP_DF);
888
889                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
890
891                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
892                         if (t != NULL) {
893                                 if (t->dev != dev) {
894                                         err = -EEXIST;
895                                         break;
896                                 }
897                         } else {
898                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
899                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
900                                         err = -EINVAL;
901                                         break;
902                                 }
903                                 t = netdev_priv(dev);
904                                 ipip6_tunnel_unlink(sitn, t);
905                                 t->parms.iph.saddr = p.iph.saddr;
906                                 t->parms.iph.daddr = p.iph.daddr;
907                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
908                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
909                                 ipip6_tunnel_link(sitn, t);
910                                 netdev_state_change(dev);
911                         }
912                 }
913
914                 if (t) {
915                         err = 0;
916                         if (cmd == SIOCCHGTUNNEL) {
917                                 t->parms.iph.ttl = p.iph.ttl;
918                                 t->parms.iph.tos = p.iph.tos;
919                                 if (t->parms.link != p.link) {
920                                         t->parms.link = p.link;
921                                         ipip6_tunnel_bind_dev(dev);
922                                         netdev_state_change(dev);
923                                 }
924                         }
925                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
926                                 err = -EFAULT;
927                 } else
928                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
929                 break;
930
931         case SIOCDELTUNNEL:
932                 err = -EPERM;
933                 if (!capable(CAP_NET_ADMIN))
934                         goto done;
935
936                 if (dev == sitn->fb_tunnel_dev) {
937                         err = -EFAULT;
938                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
939                                 goto done;
940                         err = -ENOENT;
941                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
942                                 goto done;
943                         err = -EPERM;
944                         if (t == netdev_priv(sitn->fb_tunnel_dev))
945                                 goto done;
946                         dev = t->dev;
947                 }
948                 unregister_netdevice(dev);
949                 err = 0;
950                 break;
951
952         case SIOCGETPRL:
953                 err = -EINVAL;
954                 if (dev == sitn->fb_tunnel_dev)
955                         goto done;
956                 err = -ENOENT;
957                 if (!(t = netdev_priv(dev)))
958                         goto done;
959                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
960                 break;
961
962         case SIOCADDPRL:
963         case SIOCDELPRL:
964         case SIOCCHGPRL:
965                 err = -EPERM;
966                 if (!capable(CAP_NET_ADMIN))
967                         goto done;
968                 err = -EINVAL;
969                 if (dev == sitn->fb_tunnel_dev)
970                         goto done;
971                 err = -EFAULT;
972                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
973                         goto done;
974                 err = -ENOENT;
975                 if (!(t = netdev_priv(dev)))
976                         goto done;
977
978                 switch (cmd) {
979                 case SIOCDELPRL:
980                         err = ipip6_tunnel_del_prl(t, &prl);
981                         break;
982                 case SIOCADDPRL:
983                 case SIOCCHGPRL:
984                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
985                         break;
986                 }
987                 netdev_state_change(dev);
988                 break;
989
990         default:
991                 err = -EINVAL;
992         }
993
994 done:
995         return err;
996 }
997
998 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
999 {
1000         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1001                 return -EINVAL;
1002         dev->mtu = new_mtu;
1003         return 0;
1004 }
1005
1006 static const struct net_device_ops ipip6_netdev_ops = {
1007         .ndo_uninit     = ipip6_tunnel_uninit,
1008         .ndo_start_xmit = ipip6_tunnel_xmit,
1009         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1010         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1011 };
1012
1013 static void ipip6_tunnel_setup(struct net_device *dev)
1014 {
1015         dev->netdev_ops         = &ipip6_netdev_ops;
1016         dev->destructor         = free_netdev;
1017
1018         dev->type               = ARPHRD_SIT;
1019         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1020         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1021         dev->flags              = IFF_NOARP;
1022         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1023         dev->iflink             = 0;
1024         dev->addr_len           = 4;
1025         dev->features           |= NETIF_F_NETNS_LOCAL;
1026 }
1027
1028 static void ipip6_tunnel_init(struct net_device *dev)
1029 {
1030         struct ip_tunnel *tunnel = netdev_priv(dev);
1031
1032         tunnel->dev = dev;
1033         strcpy(tunnel->parms.name, dev->name);
1034
1035         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1036         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1037
1038         ipip6_tunnel_bind_dev(dev);
1039 }
1040
1041 static void ipip6_fb_tunnel_init(struct net_device *dev)
1042 {
1043         struct ip_tunnel *tunnel = netdev_priv(dev);
1044         struct iphdr *iph = &tunnel->parms.iph;
1045         struct net *net = dev_net(dev);
1046         struct sit_net *sitn = net_generic(net, sit_net_id);
1047
1048         tunnel->dev = dev;
1049         strcpy(tunnel->parms.name, dev->name);
1050
1051         iph->version            = 4;
1052         iph->protocol           = IPPROTO_IPV6;
1053         iph->ihl                = 5;
1054         iph->ttl                = 64;
1055
1056         dev_hold(dev);
1057         sitn->tunnels_wc[0]     = tunnel;
1058 }
1059
1060 static struct xfrm_tunnel sit_handler = {
1061         .handler        =       ipip6_rcv,
1062         .err_handler    =       ipip6_err,
1063         .priority       =       1,
1064 };
1065
1066 static void sit_destroy_tunnels(struct sit_net *sitn)
1067 {
1068         int prio;
1069
1070         for (prio = 1; prio < 4; prio++) {
1071                 int h;
1072                 for (h = 0; h < HASH_SIZE; h++) {
1073                         struct ip_tunnel *t;
1074                         while ((t = sitn->tunnels[prio][h]) != NULL)
1075                                 unregister_netdevice(t->dev);
1076                 }
1077         }
1078 }
1079
1080 static int sit_init_net(struct net *net)
1081 {
1082         int err;
1083         struct sit_net *sitn;
1084
1085         err = -ENOMEM;
1086         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1087         if (sitn == NULL)
1088                 goto err_alloc;
1089
1090         err = net_assign_generic(net, sit_net_id, sitn);
1091         if (err < 0)
1092                 goto err_assign;
1093
1094         sitn->tunnels[0] = sitn->tunnels_wc;
1095         sitn->tunnels[1] = sitn->tunnels_l;
1096         sitn->tunnels[2] = sitn->tunnels_r;
1097         sitn->tunnels[3] = sitn->tunnels_r_l;
1098
1099         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1100                                            ipip6_tunnel_setup);
1101         if (!sitn->fb_tunnel_dev) {
1102                 err = -ENOMEM;
1103                 goto err_alloc_dev;
1104         }
1105         dev_net_set(sitn->fb_tunnel_dev, net);
1106
1107         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1108
1109         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1110                 goto err_reg_dev;
1111
1112         return 0;
1113
1114 err_reg_dev:
1115         dev_put(sitn->fb_tunnel_dev);
1116         free_netdev(sitn->fb_tunnel_dev);
1117 err_alloc_dev:
1118         /* nothing */
1119 err_assign:
1120         kfree(sitn);
1121 err_alloc:
1122         return err;
1123 }
1124
1125 static void sit_exit_net(struct net *net)
1126 {
1127         struct sit_net *sitn;
1128
1129         sitn = net_generic(net, sit_net_id);
1130         rtnl_lock();
1131         sit_destroy_tunnels(sitn);
1132         unregister_netdevice(sitn->fb_tunnel_dev);
1133         rtnl_unlock();
1134         kfree(sitn);
1135 }
1136
1137 static struct pernet_operations sit_net_ops = {
1138         .init = sit_init_net,
1139         .exit = sit_exit_net,
1140 };
1141
1142 static void __exit sit_cleanup(void)
1143 {
1144         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1145
1146         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1147 }
1148
1149 static int __init sit_init(void)
1150 {
1151         int err;
1152
1153         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1154
1155         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1156                 printk(KERN_INFO "sit init: Can't add protocol\n");
1157                 return -EAGAIN;
1158         }
1159
1160         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1161         if (err < 0)
1162                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1163
1164         return err;
1165 }
1166
1167 module_init(sit_init);
1168 module_exit(sit_cleanup);
1169 MODULE_LICENSE("GPL");
1170 MODULE_ALIAS("sit0");