]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - net/ipv6/sit.c
tunnel: eliminate recursion field
[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 (skb->protocol != htons(ETH_P_IPV6))
630                 goto tx_error;
631
632         /* ISATAP (RFC4214) - must come before 6to4 */
633         if (dev->priv_flags & IFF_ISATAP) {
634                 struct neighbour *neigh = NULL;
635
636                 if (skb_dst(skb))
637                         neigh = skb_dst(skb)->neighbour;
638
639                 if (neigh == NULL) {
640                         if (net_ratelimit())
641                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
642                         goto tx_error;
643                 }
644
645                 addr6 = (struct in6_addr*)&neigh->primary_key;
646                 addr_type = ipv6_addr_type(addr6);
647
648                 if ((addr_type & IPV6_ADDR_UNICAST) &&
649                      ipv6_addr_is_isatap(addr6))
650                         dst = addr6->s6_addr32[3];
651                 else
652                         goto tx_error;
653         }
654
655         if (!dst)
656                 dst = try_6to4(&iph6->daddr);
657
658         if (!dst) {
659                 struct neighbour *neigh = NULL;
660
661                 if (skb_dst(skb))
662                         neigh = skb_dst(skb)->neighbour;
663
664                 if (neigh == NULL) {
665                         if (net_ratelimit())
666                                 printk(KERN_DEBUG "sit: nexthop == NULL\n");
667                         goto tx_error;
668                 }
669
670                 addr6 = (struct in6_addr*)&neigh->primary_key;
671                 addr_type = ipv6_addr_type(addr6);
672
673                 if (addr_type == IPV6_ADDR_ANY) {
674                         addr6 = &ipv6_hdr(skb)->daddr;
675                         addr_type = ipv6_addr_type(addr6);
676                 }
677
678                 if ((addr_type & IPV6_ADDR_COMPATv4) == 0)
679                         goto tx_error_icmp;
680
681                 dst = addr6->s6_addr32[3];
682         }
683
684         {
685                 struct flowi fl = { .nl_u = { .ip4_u =
686                                               { .daddr = dst,
687                                                 .saddr = tiph->saddr,
688                                                 .tos = RT_TOS(tos) } },
689                                     .oif = tunnel->parms.link,
690                                     .proto = IPPROTO_IPV6 };
691                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
692                         stats->tx_carrier_errors++;
693                         goto tx_error_icmp;
694                 }
695         }
696         if (rt->rt_type != RTN_UNICAST) {
697                 ip_rt_put(rt);
698                 stats->tx_carrier_errors++;
699                 goto tx_error_icmp;
700         }
701         tdev = rt->u.dst.dev;
702
703         if (tdev == dev) {
704                 ip_rt_put(rt);
705                 stats->collisions++;
706                 goto tx_error;
707         }
708
709         if (tiph->frag_off)
710                 mtu = dst_mtu(&rt->u.dst) - sizeof(struct iphdr);
711         else
712                 mtu = skb_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
713
714         if (mtu < 68) {
715                 stats->collisions++;
716                 ip_rt_put(rt);
717                 goto tx_error;
718         }
719         if (mtu < IPV6_MIN_MTU)
720                 mtu = IPV6_MIN_MTU;
721         if (tunnel->parms.iph.daddr && skb_dst(skb))
722                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
723
724         if (skb->len > mtu) {
725                 icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu, dev);
726                 ip_rt_put(rt);
727                 goto tx_error;
728         }
729
730         if (tunnel->err_count > 0) {
731                 if (time_before(jiffies,
732                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
733                         tunnel->err_count--;
734                         dst_link_failure(skb);
735                 } else
736                         tunnel->err_count = 0;
737         }
738
739         /*
740          * Okay, now see if we can stuff it in the buffer as-is.
741          */
742         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
743
744         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
745             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
746                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
747                 if (!new_skb) {
748                         ip_rt_put(rt);
749                         stats->tx_dropped++;
750                         dev_kfree_skb(skb);
751                         return NETDEV_TX_OK;
752                 }
753                 if (skb->sk)
754                         skb_set_owner_w(new_skb, skb->sk);
755                 dev_kfree_skb(skb);
756                 skb = new_skb;
757                 iph6 = ipv6_hdr(skb);
758         }
759
760         skb->transport_header = skb->network_header;
761         skb_push(skb, sizeof(struct iphdr));
762         skb_reset_network_header(skb);
763         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
764         IPCB(skb)->flags = 0;
765         skb_dst_drop(skb);
766         skb_dst_set(skb, &rt->u.dst);
767
768         /*
769          *      Push down and install the IPIP header.
770          */
771
772         iph                     =       ip_hdr(skb);
773         iph->version            =       4;
774         iph->ihl                =       sizeof(struct iphdr)>>2;
775         if (mtu > IPV6_MIN_MTU)
776                 iph->frag_off   =       tiph->frag_off;
777         else
778                 iph->frag_off   =       0;
779
780         iph->protocol           =       IPPROTO_IPV6;
781         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
782         iph->daddr              =       rt->rt_dst;
783         iph->saddr              =       rt->rt_src;
784
785         if ((iph->ttl = tiph->ttl) == 0)
786                 iph->ttl        =       iph6->hop_limit;
787
788         nf_reset(skb);
789
790         IPTUNNEL_XMIT();
791         return NETDEV_TX_OK;
792
793 tx_error_icmp:
794         dst_link_failure(skb);
795 tx_error:
796         stats->tx_errors++;
797         dev_kfree_skb(skb);
798         return NETDEV_TX_OK;
799 }
800
801 static void ipip6_tunnel_bind_dev(struct net_device *dev)
802 {
803         struct net_device *tdev = NULL;
804         struct ip_tunnel *tunnel;
805         struct iphdr *iph;
806
807         tunnel = netdev_priv(dev);
808         iph = &tunnel->parms.iph;
809
810         if (iph->daddr) {
811                 struct flowi fl = { .nl_u = { .ip4_u =
812                                               { .daddr = iph->daddr,
813                                                 .saddr = iph->saddr,
814                                                 .tos = RT_TOS(iph->tos) } },
815                                     .oif = tunnel->parms.link,
816                                     .proto = IPPROTO_IPV6 };
817                 struct rtable *rt;
818                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
819                         tdev = rt->u.dst.dev;
820                         ip_rt_put(rt);
821                 }
822                 dev->flags |= IFF_POINTOPOINT;
823         }
824
825         if (!tdev && tunnel->parms.link)
826                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
827
828         if (tdev) {
829                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
830                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
831                 if (dev->mtu < IPV6_MIN_MTU)
832                         dev->mtu = IPV6_MIN_MTU;
833         }
834         dev->iflink = tunnel->parms.link;
835 }
836
837 static int
838 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
839 {
840         int err = 0;
841         struct ip_tunnel_parm p;
842         struct ip_tunnel_prl prl;
843         struct ip_tunnel *t;
844         struct net *net = dev_net(dev);
845         struct sit_net *sitn = net_generic(net, sit_net_id);
846
847         switch (cmd) {
848         case SIOCGETTUNNEL:
849                 t = NULL;
850                 if (dev == sitn->fb_tunnel_dev) {
851                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
852                                 err = -EFAULT;
853                                 break;
854                         }
855                         t = ipip6_tunnel_locate(net, &p, 0);
856                 }
857                 if (t == NULL)
858                         t = netdev_priv(dev);
859                 memcpy(&p, &t->parms, sizeof(p));
860                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
861                         err = -EFAULT;
862                 break;
863
864         case SIOCADDTUNNEL:
865         case SIOCCHGTUNNEL:
866                 err = -EPERM;
867                 if (!capable(CAP_NET_ADMIN))
868                         goto done;
869
870                 err = -EFAULT;
871                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
872                         goto done;
873
874                 err = -EINVAL;
875                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
876                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
877                         goto done;
878                 if (p.iph.ttl)
879                         p.iph.frag_off |= htons(IP_DF);
880
881                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
882
883                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
884                         if (t != NULL) {
885                                 if (t->dev != dev) {
886                                         err = -EEXIST;
887                                         break;
888                                 }
889                         } else {
890                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
891                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
892                                         err = -EINVAL;
893                                         break;
894                                 }
895                                 t = netdev_priv(dev);
896                                 ipip6_tunnel_unlink(sitn, t);
897                                 t->parms.iph.saddr = p.iph.saddr;
898                                 t->parms.iph.daddr = p.iph.daddr;
899                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
900                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
901                                 ipip6_tunnel_link(sitn, t);
902                                 netdev_state_change(dev);
903                         }
904                 }
905
906                 if (t) {
907                         err = 0;
908                         if (cmd == SIOCCHGTUNNEL) {
909                                 t->parms.iph.ttl = p.iph.ttl;
910                                 t->parms.iph.tos = p.iph.tos;
911                                 if (t->parms.link != p.link) {
912                                         t->parms.link = p.link;
913                                         ipip6_tunnel_bind_dev(dev);
914                                         netdev_state_change(dev);
915                                 }
916                         }
917                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
918                                 err = -EFAULT;
919                 } else
920                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
921                 break;
922
923         case SIOCDELTUNNEL:
924                 err = -EPERM;
925                 if (!capable(CAP_NET_ADMIN))
926                         goto done;
927
928                 if (dev == sitn->fb_tunnel_dev) {
929                         err = -EFAULT;
930                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
931                                 goto done;
932                         err = -ENOENT;
933                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
934                                 goto done;
935                         err = -EPERM;
936                         if (t == netdev_priv(sitn->fb_tunnel_dev))
937                                 goto done;
938                         dev = t->dev;
939                 }
940                 unregister_netdevice(dev);
941                 err = 0;
942                 break;
943
944         case SIOCGETPRL:
945                 err = -EINVAL;
946                 if (dev == sitn->fb_tunnel_dev)
947                         goto done;
948                 err = -ENOENT;
949                 if (!(t = netdev_priv(dev)))
950                         goto done;
951                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
952                 break;
953
954         case SIOCADDPRL:
955         case SIOCDELPRL:
956         case SIOCCHGPRL:
957                 err = -EPERM;
958                 if (!capable(CAP_NET_ADMIN))
959                         goto done;
960                 err = -EINVAL;
961                 if (dev == sitn->fb_tunnel_dev)
962                         goto done;
963                 err = -EFAULT;
964                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
965                         goto done;
966                 err = -ENOENT;
967                 if (!(t = netdev_priv(dev)))
968                         goto done;
969
970                 switch (cmd) {
971                 case SIOCDELPRL:
972                         err = ipip6_tunnel_del_prl(t, &prl);
973                         break;
974                 case SIOCADDPRL:
975                 case SIOCCHGPRL:
976                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
977                         break;
978                 }
979                 netdev_state_change(dev);
980                 break;
981
982         default:
983                 err = -EINVAL;
984         }
985
986 done:
987         return err;
988 }
989
990 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
991 {
992         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
993                 return -EINVAL;
994         dev->mtu = new_mtu;
995         return 0;
996 }
997
998 static const struct net_device_ops ipip6_netdev_ops = {
999         .ndo_uninit     = ipip6_tunnel_uninit,
1000         .ndo_start_xmit = ipip6_tunnel_xmit,
1001         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1002         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1003 };
1004
1005 static void ipip6_tunnel_setup(struct net_device *dev)
1006 {
1007         dev->netdev_ops         = &ipip6_netdev_ops;
1008         dev->destructor         = free_netdev;
1009
1010         dev->type               = ARPHRD_SIT;
1011         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1012         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1013         dev->flags              = IFF_NOARP;
1014         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1015         dev->iflink             = 0;
1016         dev->addr_len           = 4;
1017         dev->features           |= NETIF_F_NETNS_LOCAL;
1018 }
1019
1020 static void ipip6_tunnel_init(struct net_device *dev)
1021 {
1022         struct ip_tunnel *tunnel = netdev_priv(dev);
1023
1024         tunnel->dev = dev;
1025         strcpy(tunnel->parms.name, dev->name);
1026
1027         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1028         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1029
1030         ipip6_tunnel_bind_dev(dev);
1031 }
1032
1033 static void ipip6_fb_tunnel_init(struct net_device *dev)
1034 {
1035         struct ip_tunnel *tunnel = netdev_priv(dev);
1036         struct iphdr *iph = &tunnel->parms.iph;
1037         struct net *net = dev_net(dev);
1038         struct sit_net *sitn = net_generic(net, sit_net_id);
1039
1040         tunnel->dev = dev;
1041         strcpy(tunnel->parms.name, dev->name);
1042
1043         iph->version            = 4;
1044         iph->protocol           = IPPROTO_IPV6;
1045         iph->ihl                = 5;
1046         iph->ttl                = 64;
1047
1048         dev_hold(dev);
1049         sitn->tunnels_wc[0]     = tunnel;
1050 }
1051
1052 static struct xfrm_tunnel sit_handler = {
1053         .handler        =       ipip6_rcv,
1054         .err_handler    =       ipip6_err,
1055         .priority       =       1,
1056 };
1057
1058 static void sit_destroy_tunnels(struct sit_net *sitn)
1059 {
1060         int prio;
1061
1062         for (prio = 1; prio < 4; prio++) {
1063                 int h;
1064                 for (h = 0; h < HASH_SIZE; h++) {
1065                         struct ip_tunnel *t;
1066                         while ((t = sitn->tunnels[prio][h]) != NULL)
1067                                 unregister_netdevice(t->dev);
1068                 }
1069         }
1070 }
1071
1072 static int sit_init_net(struct net *net)
1073 {
1074         int err;
1075         struct sit_net *sitn;
1076
1077         err = -ENOMEM;
1078         sitn = kzalloc(sizeof(struct sit_net), GFP_KERNEL);
1079         if (sitn == NULL)
1080                 goto err_alloc;
1081
1082         err = net_assign_generic(net, sit_net_id, sitn);
1083         if (err < 0)
1084                 goto err_assign;
1085
1086         sitn->tunnels[0] = sitn->tunnels_wc;
1087         sitn->tunnels[1] = sitn->tunnels_l;
1088         sitn->tunnels[2] = sitn->tunnels_r;
1089         sitn->tunnels[3] = sitn->tunnels_r_l;
1090
1091         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1092                                            ipip6_tunnel_setup);
1093         if (!sitn->fb_tunnel_dev) {
1094                 err = -ENOMEM;
1095                 goto err_alloc_dev;
1096         }
1097         dev_net_set(sitn->fb_tunnel_dev, net);
1098
1099         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1100
1101         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1102                 goto err_reg_dev;
1103
1104         return 0;
1105
1106 err_reg_dev:
1107         dev_put(sitn->fb_tunnel_dev);
1108         free_netdev(sitn->fb_tunnel_dev);
1109 err_alloc_dev:
1110         /* nothing */
1111 err_assign:
1112         kfree(sitn);
1113 err_alloc:
1114         return err;
1115 }
1116
1117 static void sit_exit_net(struct net *net)
1118 {
1119         struct sit_net *sitn;
1120
1121         sitn = net_generic(net, sit_net_id);
1122         rtnl_lock();
1123         sit_destroy_tunnels(sitn);
1124         unregister_netdevice(sitn->fb_tunnel_dev);
1125         rtnl_unlock();
1126         kfree(sitn);
1127 }
1128
1129 static struct pernet_operations sit_net_ops = {
1130         .init = sit_init_net,
1131         .exit = sit_exit_net,
1132 };
1133
1134 static void __exit sit_cleanup(void)
1135 {
1136         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1137
1138         unregister_pernet_gen_device(sit_net_id, &sit_net_ops);
1139 }
1140
1141 static int __init sit_init(void)
1142 {
1143         int err;
1144
1145         printk(KERN_INFO "IPv6 over IPv4 tunneling driver\n");
1146
1147         if (xfrm4_tunnel_register(&sit_handler, AF_INET6) < 0) {
1148                 printk(KERN_INFO "sit init: Can't add protocol\n");
1149                 return -EAGAIN;
1150         }
1151
1152         err = register_pernet_gen_device(&sit_net_id, &sit_net_ops);
1153         if (err < 0)
1154                 xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1155
1156         return err;
1157 }
1158
1159 module_init(sit_init);
1160 module_exit(sit_cleanup);
1161 MODULE_LICENSE("GPL");
1162 MODULE_ALIAS("sit0");