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TOMOYO Linux Cross Reference
Linux/net/ipv6/sit.c

Version: ~ [ linux-5.5-rc7 ] ~ [ linux-5.4.13 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.97 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.166 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.210 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.210 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.81 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 21 
 22 #include <linux/module.h>
 23 #include <linux/capability.h>
 24 #include <linux/errno.h>
 25 #include <linux/types.h>
 26 #include <linux/socket.h>
 27 #include <linux/sockios.h>
 28 #include <linux/net.h>
 29 #include <linux/in6.h>
 30 #include <linux/netdevice.h>
 31 #include <linux/if_arp.h>
 32 #include <linux/icmp.h>
 33 #include <linux/slab.h>
 34 #include <asm/uaccess.h>
 35 #include <linux/init.h>
 36 #include <linux/netfilter_ipv4.h>
 37 #include <linux/if_ether.h>
 38 
 39 #include <net/sock.h>
 40 #include <net/snmp.h>
 41 
 42 #include <net/ipv6.h>
 43 #include <net/protocol.h>
 44 #include <net/transp_v6.h>
 45 #include <net/ip6_fib.h>
 46 #include <net/ip6_route.h>
 47 #include <net/ndisc.h>
 48 #include <net/addrconf.h>
 49 #include <net/ip.h>
 50 #include <net/udp.h>
 51 #include <net/icmp.h>
 52 #include <net/ipip.h>
 53 #include <net/inet_ecn.h>
 54 #include <net/xfrm.h>
 55 #include <net/dsfield.h>
 56 #include <net/net_namespace.h>
 57 #include <net/netns/generic.h>
 58 
 59 /*
 60    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
 61 
 62    For comments look at net/ipv4/ip_gre.c --ANK
 63  */
 64 
 65 #define HASH_SIZE  16
 66 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 67 
 68 static int ipip6_tunnel_init(struct net_device *dev);
 69 static void ipip6_tunnel_setup(struct net_device *dev);
 70 static void ipip6_dev_free(struct net_device *dev);
 71 
 72 static int sit_net_id __read_mostly;
 73 struct sit_net {
 74         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
 75         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
 76         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
 77         struct ip_tunnel __rcu *tunnels_wc[1];
 78         struct ip_tunnel __rcu **tunnels[4];
 79 
 80         struct net_device *fb_tunnel_dev;
 81 };
 82 
 83 /*
 84  * Locking : hash tables are protected by RCU and RTNL
 85  */
 86 
 87 #define for_each_ip_tunnel_rcu(start) \
 88         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
 89 
 90 /* often modified stats are per cpu, other are shared (netdev->stats) */
 91 struct pcpu_tstats {
 92         u64     rx_packets;
 93         u64     rx_bytes;
 94         u64     tx_packets;
 95         u64     tx_bytes;
 96         struct u64_stats_sync   syncp;
 97 };
 98 
 99 static struct rtnl_link_stats64 *ipip6_get_stats64(struct net_device *dev,
100                                                    struct rtnl_link_stats64 *tot)
101 {
102         int i;
103 
104         for_each_possible_cpu(i) {
105                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
106                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
107                 unsigned int start;
108 
109                 do {
110                         start = u64_stats_fetch_begin_bh(&tstats->syncp);
111                         rx_packets = tstats->rx_packets;
112                         tx_packets = tstats->tx_packets;
113                         rx_bytes = tstats->rx_bytes;
114                         tx_bytes = tstats->tx_bytes;
115                 } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
116 
117                 tot->rx_packets += rx_packets;
118                 tot->tx_packets += tx_packets;
119                 tot->rx_bytes   += rx_bytes;
120                 tot->tx_bytes   += tx_bytes;
121         }
122 
123         tot->rx_errors = dev->stats.rx_errors;
124         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
125         tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
126         tot->tx_dropped = dev->stats.tx_dropped;
127         tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
128         tot->tx_errors = dev->stats.tx_errors;
129 
130         return tot;
131 }
132 
133 /*
134  * Must be invoked with rcu_read_lock
135  */
136 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
137                 struct net_device *dev, __be32 remote, __be32 local)
138 {
139         unsigned int h0 = HASH(remote);
140         unsigned int h1 = HASH(local);
141         struct ip_tunnel *t;
142         struct sit_net *sitn = net_generic(net, sit_net_id);
143 
144         for_each_ip_tunnel_rcu(sitn->tunnels_r_l[h0 ^ h1]) {
145                 if (local == t->parms.iph.saddr &&
146                     remote == t->parms.iph.daddr &&
147                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
148                     (t->dev->flags & IFF_UP))
149                         return t;
150         }
151         for_each_ip_tunnel_rcu(sitn->tunnels_r[h0]) {
152                 if (remote == t->parms.iph.daddr &&
153                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
154                     (t->dev->flags & IFF_UP))
155                         return t;
156         }
157         for_each_ip_tunnel_rcu(sitn->tunnels_l[h1]) {
158                 if (local == t->parms.iph.saddr &&
159                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
160                     (t->dev->flags & IFF_UP))
161                         return t;
162         }
163         t = rcu_dereference(sitn->tunnels_wc[0]);
164         if ((t != NULL) && (t->dev->flags & IFF_UP))
165                 return t;
166         return NULL;
167 }
168 
169 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
170                 struct ip_tunnel_parm *parms)
171 {
172         __be32 remote = parms->iph.daddr;
173         __be32 local = parms->iph.saddr;
174         unsigned int h = 0;
175         int prio = 0;
176 
177         if (remote) {
178                 prio |= 2;
179                 h ^= HASH(remote);
180         }
181         if (local) {
182                 prio |= 1;
183                 h ^= HASH(local);
184         }
185         return &sitn->tunnels[prio][h];
186 }
187 
188 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
189                 struct ip_tunnel *t)
190 {
191         return __ipip6_bucket(sitn, &t->parms);
192 }
193 
194 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
195 {
196         struct ip_tunnel __rcu **tp;
197         struct ip_tunnel *iter;
198 
199         for (tp = ipip6_bucket(sitn, t);
200              (iter = rtnl_dereference(*tp)) != NULL;
201              tp = &iter->next) {
202                 if (t == iter) {
203                         rcu_assign_pointer(*tp, t->next);
204                         break;
205                 }
206         }
207 }
208 
209 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
210 {
211         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
212 
213         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
214         rcu_assign_pointer(*tp, t);
215 }
216 
217 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
218 {
219 #ifdef CONFIG_IPV6_SIT_6RD
220         struct ip_tunnel *t = netdev_priv(dev);
221 
222         if (t->dev == sitn->fb_tunnel_dev) {
223                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
224                 t->ip6rd.relay_prefix = 0;
225                 t->ip6rd.prefixlen = 16;
226                 t->ip6rd.relay_prefixlen = 0;
227         } else {
228                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
229                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
230         }
231 #endif
232 }
233 
234 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
235                 struct ip_tunnel_parm *parms, int create)
236 {
237         __be32 remote = parms->iph.daddr;
238         __be32 local = parms->iph.saddr;
239         struct ip_tunnel *t, *nt;
240         struct ip_tunnel __rcu **tp;
241         struct net_device *dev;
242         char name[IFNAMSIZ];
243         struct sit_net *sitn = net_generic(net, sit_net_id);
244 
245         for (tp = __ipip6_bucket(sitn, parms);
246             (t = rtnl_dereference(*tp)) != NULL;
247              tp = &t->next) {
248                 if (local == t->parms.iph.saddr &&
249                     remote == t->parms.iph.daddr &&
250                     parms->link == t->parms.link) {
251                         if (create)
252                                 return NULL;
253                         else
254                                 return t;
255                 }
256         }
257         if (!create)
258                 goto failed;
259 
260         if (parms->name[0])
261                 strlcpy(name, parms->name, IFNAMSIZ);
262         else
263                 strcpy(name, "sit%d");
264 
265         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
266         if (dev == NULL)
267                 return NULL;
268 
269         dev_net_set(dev, net);
270 
271         nt = netdev_priv(dev);
272 
273         nt->parms = *parms;
274         if (ipip6_tunnel_init(dev) < 0)
275                 goto failed_free;
276         ipip6_tunnel_clone_6rd(dev, sitn);
277 
278         if (parms->i_flags & SIT_ISATAP)
279                 dev->priv_flags |= IFF_ISATAP;
280 
281         if (register_netdevice(dev) < 0)
282                 goto failed_free;
283 
284         strcpy(nt->parms.name, dev->name);
285 
286         dev_hold(dev);
287 
288         ipip6_tunnel_link(sitn, nt);
289         return nt;
290 
291 failed_free:
292         ipip6_dev_free(dev);
293 failed:
294         return NULL;
295 }
296 
297 #define for_each_prl_rcu(start)                 \
298         for (prl = rcu_dereference(start);      \
299              prl;                               \
300              prl = rcu_dereference(prl->next))
301 
302 static struct ip_tunnel_prl_entry *
303 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
304 {
305         struct ip_tunnel_prl_entry *prl;
306 
307         for_each_prl_rcu(t->prl)
308                 if (prl->addr == addr)
309                         break;
310         return prl;
311 
312 }
313 
314 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
315                                 struct ip_tunnel_prl __user *a)
316 {
317         struct ip_tunnel_prl kprl, *kp;
318         struct ip_tunnel_prl_entry *prl;
319         unsigned int cmax, c = 0, ca, len;
320         int ret = 0;
321 
322         if (copy_from_user(&kprl, a, sizeof(kprl)))
323                 return -EFAULT;
324         cmax = kprl.datalen / sizeof(kprl);
325         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
326                 cmax = 1;
327 
328         /* For simple GET or for root users,
329          * we try harder to allocate.
330          */
331         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
332                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
333                 NULL;
334 
335         rcu_read_lock();
336 
337         ca = t->prl_count < cmax ? t->prl_count : cmax;
338 
339         if (!kp) {
340                 /* We don't try hard to allocate much memory for
341                  * non-root users.
342                  * For root users, retry allocating enough memory for
343                  * the answer.
344                  */
345                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
346                 if (!kp) {
347                         ret = -ENOMEM;
348                         goto out;
349                 }
350         }
351 
352         c = 0;
353         for_each_prl_rcu(t->prl) {
354                 if (c >= cmax)
355                         break;
356                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
357                         continue;
358                 kp[c].addr = prl->addr;
359                 kp[c].flags = prl->flags;
360                 c++;
361                 if (kprl.addr != htonl(INADDR_ANY))
362                         break;
363         }
364 out:
365         rcu_read_unlock();
366 
367         len = sizeof(*kp) * c;
368         ret = 0;
369         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
370                 ret = -EFAULT;
371 
372         kfree(kp);
373 
374         return ret;
375 }
376 
377 static int
378 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
379 {
380         struct ip_tunnel_prl_entry *p;
381         int err = 0;
382 
383         if (a->addr == htonl(INADDR_ANY))
384                 return -EINVAL;
385 
386         ASSERT_RTNL();
387 
388         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
389                 if (p->addr == a->addr) {
390                         if (chg) {
391                                 p->flags = a->flags;
392                                 goto out;
393                         }
394                         err = -EEXIST;
395                         goto out;
396                 }
397         }
398 
399         if (chg) {
400                 err = -ENXIO;
401                 goto out;
402         }
403 
404         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
405         if (!p) {
406                 err = -ENOBUFS;
407                 goto out;
408         }
409 
410         p->next = t->prl;
411         p->addr = a->addr;
412         p->flags = a->flags;
413         t->prl_count++;
414         rcu_assign_pointer(t->prl, p);
415 out:
416         return err;
417 }
418 
419 static void prl_list_destroy_rcu(struct rcu_head *head)
420 {
421         struct ip_tunnel_prl_entry *p, *n;
422 
423         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
424         do {
425                 n = rcu_dereference_protected(p->next, 1);
426                 kfree(p);
427                 p = n;
428         } while (p);
429 }
430 
431 static int
432 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
433 {
434         struct ip_tunnel_prl_entry *x;
435         struct ip_tunnel_prl_entry __rcu **p;
436         int err = 0;
437 
438         ASSERT_RTNL();
439 
440         if (a && a->addr != htonl(INADDR_ANY)) {
441                 for (p = &t->prl;
442                      (x = rtnl_dereference(*p)) != NULL;
443                      p = &x->next) {
444                         if (x->addr == a->addr) {
445                                 *p = x->next;
446                                 kfree_rcu(x, rcu_head);
447                                 t->prl_count--;
448                                 goto out;
449                         }
450                 }
451                 err = -ENXIO;
452         } else {
453                 x = rtnl_dereference(t->prl);
454                 if (x) {
455                         t->prl_count = 0;
456                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
457                         t->prl = NULL;
458                 }
459         }
460 out:
461         return err;
462 }
463 
464 static int
465 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
466 {
467         struct ip_tunnel_prl_entry *p;
468         int ok = 1;
469 
470         rcu_read_lock();
471         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
472         if (p) {
473                 if (p->flags & PRL_DEFAULT)
474                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
475                 else
476                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
477         } else {
478                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
479 
480                 if (ipv6_addr_is_isatap(addr6) &&
481                     (addr6->s6_addr32[3] == iph->saddr) &&
482                     ipv6_chk_prefix(addr6, t->dev))
483                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
484                 else
485                         ok = 0;
486         }
487         rcu_read_unlock();
488         return ok;
489 }
490 
491 static void ipip6_tunnel_uninit(struct net_device *dev)
492 {
493         struct net *net = dev_net(dev);
494         struct sit_net *sitn = net_generic(net, sit_net_id);
495 
496         if (dev == sitn->fb_tunnel_dev) {
497                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
498         } else {
499                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
500                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
501         }
502         dev_put(dev);
503 }
504 
505 
506 static int ipip6_err(struct sk_buff *skb, u32 info)
507 {
508 
509 /* All the routers (except for Linux) return only
510    8 bytes of packet payload. It means, that precise relaying of
511    ICMP in the real Internet is absolutely infeasible.
512  */
513         const struct iphdr *iph = (const struct iphdr *)skb->data;
514         const int type = icmp_hdr(skb)->type;
515         const int code = icmp_hdr(skb)->code;
516         struct ip_tunnel *t;
517         int err;
518 
519         switch (type) {
520         default:
521         case ICMP_PARAMETERPROB:
522                 return 0;
523 
524         case ICMP_DEST_UNREACH:
525                 switch (code) {
526                 case ICMP_SR_FAILED:
527                 case ICMP_PORT_UNREACH:
528                         /* Impossible event. */
529                         return 0;
530                 case ICMP_FRAG_NEEDED:
531                         /* Soft state for pmtu is maintained by IP core. */
532                         return 0;
533                 default:
534                         /* All others are translated to HOST_UNREACH.
535                            rfc2003 contains "deep thoughts" about NET_UNREACH,
536                            I believe they are just ether pollution. --ANK
537                          */
538                         break;
539                 }
540                 break;
541         case ICMP_TIME_EXCEEDED:
542                 if (code != ICMP_EXC_TTL)
543                         return 0;
544                 break;
545         }
546 
547         err = -ENOENT;
548 
549         rcu_read_lock();
550         t = ipip6_tunnel_lookup(dev_net(skb->dev),
551                                 skb->dev,
552                                 iph->daddr,
553                                 iph->saddr);
554         if (t == NULL || t->parms.iph.daddr == 0)
555                 goto out;
556 
557         err = 0;
558         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
559                 goto out;
560 
561         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
562                 t->err_count++;
563         else
564                 t->err_count = 1;
565         t->err_time = jiffies;
566 out:
567         rcu_read_unlock();
568         return err;
569 }
570 
571 static inline void ipip6_ecn_decapsulate(const struct iphdr *iph, struct sk_buff *skb)
572 {
573         if (INET_ECN_is_ce(iph->tos))
574                 IP6_ECN_set_ce(ipv6_hdr(skb));
575 }
576 
577 static int ipip6_rcv(struct sk_buff *skb)
578 {
579         const struct iphdr *iph;
580         struct ip_tunnel *tunnel;
581 
582         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
583                 goto out;
584 
585         iph = ip_hdr(skb);
586 
587         rcu_read_lock();
588         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
589                                      iph->saddr, iph->daddr);
590         if (tunnel != NULL) {
591                 struct pcpu_tstats *tstats;
592 
593                 secpath_reset(skb);
594                 skb->mac_header = skb->network_header;
595                 skb_reset_network_header(skb);
596                 IPCB(skb)->flags = 0;
597                 skb->protocol = htons(ETH_P_IPV6);
598                 skb->pkt_type = PACKET_HOST;
599 
600                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
601                     !isatap_chksrc(skb, iph, tunnel)) {
602                         tunnel->dev->stats.rx_errors++;
603                         rcu_read_unlock();
604                         kfree_skb(skb);
605                         return 0;
606                 }
607 
608                 tstats = this_cpu_ptr(tunnel->dev->tstats);
609                 tstats->rx_packets++;
610                 tstats->rx_bytes += skb->len;
611 
612                 __skb_tunnel_rx(skb, tunnel->dev);
613 
614                 ipip6_ecn_decapsulate(iph, skb);
615 
616                 netif_rx(skb);
617 
618                 rcu_read_unlock();
619                 return 0;
620         }
621 
622         /* no tunnel matched,  let upstream know, ipsec may handle it */
623         rcu_read_unlock();
624         return 1;
625 out:
626         kfree_skb(skb);
627         return 0;
628 }
629 
630 /*
631  * Returns the embedded IPv4 address if the IPv6 address
632  * comes from 6rd / 6to4 (RFC 3056) addr space.
633  */
634 static inline
635 __be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
636 {
637         __be32 dst = 0;
638 
639 #ifdef CONFIG_IPV6_SIT_6RD
640         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
641                               tunnel->ip6rd.prefixlen)) {
642                 unsigned int pbw0, pbi0;
643                 int pbi1;
644                 u32 d;
645 
646                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
647                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
648 
649                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
650                     tunnel->ip6rd.relay_prefixlen;
651 
652                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
653                 if (pbi1 > 0)
654                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
655                              (32 - pbi1);
656 
657                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
658         }
659 #else
660         if (v6dst->s6_addr16[0] == htons(0x2002)) {
661                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
662                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
663         }
664 #endif
665         return dst;
666 }
667 
668 /*
669  *      This function assumes it is being called from dev_queue_xmit()
670  *      and that skb is filled properly by that function.
671  */
672 
673 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
674                                      struct net_device *dev)
675 {
676         struct ip_tunnel *tunnel = netdev_priv(dev);
677         struct pcpu_tstats *tstats;
678         const struct iphdr  *tiph = &tunnel->parms.iph;
679         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
680         u8     tos = tunnel->parms.iph.tos;
681         __be16 df = tiph->frag_off;
682         struct rtable *rt;                      /* Route to the other host */
683         struct net_device *tdev;                /* Device to other host */
684         struct iphdr  *iph;                     /* Our new IP header */
685         unsigned int max_headroom;              /* The extra header space needed */
686         __be32 dst = tiph->daddr;
687         struct flowi4 fl4;
688         int    mtu;
689         const struct in6_addr *addr6;
690         int addr_type;
691 
692         if (skb->protocol != htons(ETH_P_IPV6))
693                 goto tx_error;
694 
695         if (tos == 1)
696                 tos = ipv6_get_dsfield(iph6);
697 
698         /* ISATAP (RFC4214) - must come before 6to4 */
699         if (dev->priv_flags & IFF_ISATAP) {
700                 struct neighbour *neigh = NULL;
701                 bool do_tx_error = false;
702 
703                 if (skb_dst(skb))
704                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
705 
706                 if (neigh == NULL) {
707                         net_dbg_ratelimited("sit: nexthop == NULL\n");
708                         goto tx_error;
709                 }
710 
711                 addr6 = (const struct in6_addr *)&neigh->primary_key;
712                 addr_type = ipv6_addr_type(addr6);
713 
714                 if ((addr_type & IPV6_ADDR_UNICAST) &&
715                      ipv6_addr_is_isatap(addr6))
716                         dst = addr6->s6_addr32[3];
717                 else
718                         do_tx_error = true;
719 
720                 neigh_release(neigh);
721                 if (do_tx_error)
722                         goto tx_error;
723         }
724 
725         if (!dst)
726                 dst = try_6rd(&iph6->daddr, tunnel);
727 
728         if (!dst) {
729                 struct neighbour *neigh = NULL;
730                 bool do_tx_error = false;
731 
732                 if (skb_dst(skb))
733                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
734 
735                 if (neigh == NULL) {
736                         net_dbg_ratelimited("sit: nexthop == NULL\n");
737                         goto tx_error;
738                 }
739 
740                 addr6 = (const struct in6_addr *)&neigh->primary_key;
741                 addr_type = ipv6_addr_type(addr6);
742 
743                 if (addr_type == IPV6_ADDR_ANY) {
744                         addr6 = &ipv6_hdr(skb)->daddr;
745                         addr_type = ipv6_addr_type(addr6);
746                 }
747 
748                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
749                         dst = addr6->s6_addr32[3];
750                 else
751                         do_tx_error = true;
752 
753                 neigh_release(neigh);
754                 if (do_tx_error)
755                         goto tx_error;
756         }
757 
758         rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
759                                    dst, tiph->saddr,
760                                    0, 0,
761                                    IPPROTO_IPV6, RT_TOS(tos),
762                                    tunnel->parms.link);
763         if (IS_ERR(rt)) {
764                 dev->stats.tx_carrier_errors++;
765                 goto tx_error_icmp;
766         }
767         if (rt->rt_type != RTN_UNICAST) {
768                 ip_rt_put(rt);
769                 dev->stats.tx_carrier_errors++;
770                 goto tx_error_icmp;
771         }
772         tdev = rt->dst.dev;
773 
774         if (tdev == dev) {
775                 ip_rt_put(rt);
776                 dev->stats.collisions++;
777                 goto tx_error;
778         }
779 
780         if (df) {
781                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
782 
783                 if (mtu < 68) {
784                         dev->stats.collisions++;
785                         ip_rt_put(rt);
786                         goto tx_error;
787                 }
788 
789                 if (mtu < IPV6_MIN_MTU) {
790                         mtu = IPV6_MIN_MTU;
791                         df = 0;
792                 }
793 
794                 if (tunnel->parms.iph.daddr && skb_dst(skb))
795                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
796 
797                 if (skb->len > mtu) {
798                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
799                         ip_rt_put(rt);
800                         goto tx_error;
801                 }
802         }
803 
804         if (tunnel->err_count > 0) {
805                 if (time_before(jiffies,
806                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
807                         tunnel->err_count--;
808                         dst_link_failure(skb);
809                 } else
810                         tunnel->err_count = 0;
811         }
812 
813         /*
814          * Okay, now see if we can stuff it in the buffer as-is.
815          */
816         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
817 
818         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
819             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
820                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
821                 if (!new_skb) {
822                         ip_rt_put(rt);
823                         dev->stats.tx_dropped++;
824                         dev_kfree_skb(skb);
825                         return NETDEV_TX_OK;
826                 }
827                 if (skb->sk)
828                         skb_set_owner_w(new_skb, skb->sk);
829                 dev_kfree_skb(skb);
830                 skb = new_skb;
831                 iph6 = ipv6_hdr(skb);
832         }
833 
834         skb->transport_header = skb->network_header;
835         skb_push(skb, sizeof(struct iphdr));
836         skb_reset_network_header(skb);
837         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
838         IPCB(skb)->flags = 0;
839         skb_dst_drop(skb);
840         skb_dst_set(skb, &rt->dst);
841 
842         /*
843          *      Push down and install the IPIP header.
844          */
845 
846         iph                     =       ip_hdr(skb);
847         iph->version            =       4;
848         iph->ihl                =       sizeof(struct iphdr)>>2;
849         iph->frag_off           =       df;
850         iph->protocol           =       IPPROTO_IPV6;
851         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
852         iph->daddr              =       fl4.daddr;
853         iph->saddr              =       fl4.saddr;
854 
855         if ((iph->ttl = tiph->ttl) == 0)
856                 iph->ttl        =       iph6->hop_limit;
857 
858         nf_reset(skb);
859         tstats = this_cpu_ptr(dev->tstats);
860         __IPTUNNEL_XMIT(tstats, &dev->stats);
861         return NETDEV_TX_OK;
862 
863 tx_error_icmp:
864         dst_link_failure(skb);
865 tx_error:
866         dev->stats.tx_errors++;
867         dev_kfree_skb(skb);
868         return NETDEV_TX_OK;
869 }
870 
871 static void ipip6_tunnel_bind_dev(struct net_device *dev)
872 {
873         struct net_device *tdev = NULL;
874         struct ip_tunnel *tunnel;
875         const struct iphdr *iph;
876         struct flowi4 fl4;
877 
878         tunnel = netdev_priv(dev);
879         iph = &tunnel->parms.iph;
880 
881         if (iph->daddr) {
882                 struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
883                                                           iph->daddr, iph->saddr,
884                                                           0, 0,
885                                                           IPPROTO_IPV6,
886                                                           RT_TOS(iph->tos),
887                                                           tunnel->parms.link);
888 
889                 if (!IS_ERR(rt)) {
890                         tdev = rt->dst.dev;
891                         ip_rt_put(rt);
892                 }
893                 dev->flags |= IFF_POINTOPOINT;
894         }
895 
896         if (!tdev && tunnel->parms.link)
897                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
898 
899         if (tdev) {
900                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
901                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
902                 if (dev->mtu < IPV6_MIN_MTU)
903                         dev->mtu = IPV6_MIN_MTU;
904         }
905         dev->iflink = tunnel->parms.link;
906 }
907 
908 static int
909 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
910 {
911         int err = 0;
912         struct ip_tunnel_parm p;
913         struct ip_tunnel_prl prl;
914         struct ip_tunnel *t;
915         struct net *net = dev_net(dev);
916         struct sit_net *sitn = net_generic(net, sit_net_id);
917 #ifdef CONFIG_IPV6_SIT_6RD
918         struct ip_tunnel_6rd ip6rd;
919 #endif
920 
921         switch (cmd) {
922         case SIOCGETTUNNEL:
923 #ifdef CONFIG_IPV6_SIT_6RD
924         case SIOCGET6RD:
925 #endif
926                 t = NULL;
927                 if (dev == sitn->fb_tunnel_dev) {
928                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
929                                 err = -EFAULT;
930                                 break;
931                         }
932                         t = ipip6_tunnel_locate(net, &p, 0);
933                 }
934                 if (t == NULL)
935                         t = netdev_priv(dev);
936 
937                 err = -EFAULT;
938                 if (cmd == SIOCGETTUNNEL) {
939                         memcpy(&p, &t->parms, sizeof(p));
940                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
941                                          sizeof(p)))
942                                 goto done;
943 #ifdef CONFIG_IPV6_SIT_6RD
944                 } else {
945                         ip6rd.prefix = t->ip6rd.prefix;
946                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
947                         ip6rd.prefixlen = t->ip6rd.prefixlen;
948                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
949                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
950                                          sizeof(ip6rd)))
951                                 goto done;
952 #endif
953                 }
954                 err = 0;
955                 break;
956 
957         case SIOCADDTUNNEL:
958         case SIOCCHGTUNNEL:
959                 err = -EPERM;
960                 if (!capable(CAP_NET_ADMIN))
961                         goto done;
962 
963                 err = -EFAULT;
964                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
965                         goto done;
966 
967                 err = -EINVAL;
968                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
969                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
970                         goto done;
971                 if (p.iph.ttl)
972                         p.iph.frag_off |= htons(IP_DF);
973 
974                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
975 
976                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
977                         if (t != NULL) {
978                                 if (t->dev != dev) {
979                                         err = -EEXIST;
980                                         break;
981                                 }
982                         } else {
983                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
984                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
985                                         err = -EINVAL;
986                                         break;
987                                 }
988                                 t = netdev_priv(dev);
989                                 ipip6_tunnel_unlink(sitn, t);
990                                 synchronize_net();
991                                 t->parms.iph.saddr = p.iph.saddr;
992                                 t->parms.iph.daddr = p.iph.daddr;
993                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
994                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
995                                 ipip6_tunnel_link(sitn, t);
996                                 netdev_state_change(dev);
997                         }
998                 }
999 
1000                 if (t) {
1001                         err = 0;
1002                         if (cmd == SIOCCHGTUNNEL) {
1003                                 t->parms.iph.ttl = p.iph.ttl;
1004                                 t->parms.iph.tos = p.iph.tos;
1005                                 if (t->parms.link != p.link) {
1006                                         t->parms.link = p.link;
1007                                         ipip6_tunnel_bind_dev(dev);
1008                                         netdev_state_change(dev);
1009                                 }
1010                         }
1011                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1012                                 err = -EFAULT;
1013                 } else
1014                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1015                 break;
1016 
1017         case SIOCDELTUNNEL:
1018                 err = -EPERM;
1019                 if (!capable(CAP_NET_ADMIN))
1020                         goto done;
1021 
1022                 if (dev == sitn->fb_tunnel_dev) {
1023                         err = -EFAULT;
1024                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1025                                 goto done;
1026                         err = -ENOENT;
1027                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1028                                 goto done;
1029                         err = -EPERM;
1030                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1031                                 goto done;
1032                         dev = t->dev;
1033                 }
1034                 unregister_netdevice(dev);
1035                 err = 0;
1036                 break;
1037 
1038         case SIOCGETPRL:
1039                 err = -EINVAL;
1040                 if (dev == sitn->fb_tunnel_dev)
1041                         goto done;
1042                 err = -ENOENT;
1043                 if (!(t = netdev_priv(dev)))
1044                         goto done;
1045                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1046                 break;
1047 
1048         case SIOCADDPRL:
1049         case SIOCDELPRL:
1050         case SIOCCHGPRL:
1051                 err = -EPERM;
1052                 if (!capable(CAP_NET_ADMIN))
1053                         goto done;
1054                 err = -EINVAL;
1055                 if (dev == sitn->fb_tunnel_dev)
1056                         goto done;
1057                 err = -EFAULT;
1058                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1059                         goto done;
1060                 err = -ENOENT;
1061                 if (!(t = netdev_priv(dev)))
1062                         goto done;
1063 
1064                 switch (cmd) {
1065                 case SIOCDELPRL:
1066                         err = ipip6_tunnel_del_prl(t, &prl);
1067                         break;
1068                 case SIOCADDPRL:
1069                 case SIOCCHGPRL:
1070                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1071                         break;
1072                 }
1073                 netdev_state_change(dev);
1074                 break;
1075 
1076 #ifdef CONFIG_IPV6_SIT_6RD
1077         case SIOCADD6RD:
1078         case SIOCCHG6RD:
1079         case SIOCDEL6RD:
1080                 err = -EPERM;
1081                 if (!capable(CAP_NET_ADMIN))
1082                         goto done;
1083 
1084                 err = -EFAULT;
1085                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1086                                    sizeof(ip6rd)))
1087                         goto done;
1088 
1089                 t = netdev_priv(dev);
1090 
1091                 if (cmd != SIOCDEL6RD) {
1092                         struct in6_addr prefix;
1093                         __be32 relay_prefix;
1094 
1095                         err = -EINVAL;
1096                         if (ip6rd.relay_prefixlen > 32 ||
1097                             ip6rd.prefixlen + (32 - ip6rd.relay_prefixlen) > 64)
1098                                 goto done;
1099 
1100                         ipv6_addr_prefix(&prefix, &ip6rd.prefix,
1101                                          ip6rd.prefixlen);
1102                         if (!ipv6_addr_equal(&prefix, &ip6rd.prefix))
1103                                 goto done;
1104                         if (ip6rd.relay_prefixlen)
1105                                 relay_prefix = ip6rd.relay_prefix &
1106                                                htonl(0xffffffffUL <<
1107                                                      (32 - ip6rd.relay_prefixlen));
1108                         else
1109                                 relay_prefix = 0;
1110                         if (relay_prefix != ip6rd.relay_prefix)
1111                                 goto done;
1112 
1113                         t->ip6rd.prefix = prefix;
1114                         t->ip6rd.relay_prefix = relay_prefix;
1115                         t->ip6rd.prefixlen = ip6rd.prefixlen;
1116                         t->ip6rd.relay_prefixlen = ip6rd.relay_prefixlen;
1117                 } else
1118                         ipip6_tunnel_clone_6rd(dev, sitn);
1119 
1120                 err = 0;
1121                 break;
1122 #endif
1123 
1124         default:
1125                 err = -EINVAL;
1126         }
1127 
1128 done:
1129         return err;
1130 }
1131 
1132 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1133 {
1134         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1135                 return -EINVAL;
1136         dev->mtu = new_mtu;
1137         return 0;
1138 }
1139 
1140 static const struct net_device_ops ipip6_netdev_ops = {
1141         .ndo_uninit     = ipip6_tunnel_uninit,
1142         .ndo_start_xmit = ipip6_tunnel_xmit,
1143         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1144         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1145         .ndo_get_stats64= ipip6_get_stats64,
1146 };
1147 
1148 static void ipip6_dev_free(struct net_device *dev)
1149 {
1150         free_percpu(dev->tstats);
1151         free_netdev(dev);
1152 }
1153 
1154 static void ipip6_tunnel_setup(struct net_device *dev)
1155 {
1156         dev->netdev_ops         = &ipip6_netdev_ops;
1157         dev->destructor         = ipip6_dev_free;
1158 
1159         dev->type               = ARPHRD_SIT;
1160         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1161         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1162         dev->flags              = IFF_NOARP;
1163         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1164         dev->iflink             = 0;
1165         dev->addr_len           = 4;
1166         dev->features           |= NETIF_F_NETNS_LOCAL;
1167         dev->features           |= NETIF_F_LLTX;
1168 }
1169 
1170 static int ipip6_tunnel_init(struct net_device *dev)
1171 {
1172         struct ip_tunnel *tunnel = netdev_priv(dev);
1173 
1174         tunnel->dev = dev;
1175 
1176         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1177         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1178 
1179         ipip6_tunnel_bind_dev(dev);
1180         dev->tstats = alloc_percpu(struct pcpu_tstats);
1181         if (!dev->tstats)
1182                 return -ENOMEM;
1183 
1184         return 0;
1185 }
1186 
1187 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1188 {
1189         struct ip_tunnel *tunnel = netdev_priv(dev);
1190         struct iphdr *iph = &tunnel->parms.iph;
1191         struct net *net = dev_net(dev);
1192         struct sit_net *sitn = net_generic(net, sit_net_id);
1193 
1194         tunnel->dev = dev;
1195         strcpy(tunnel->parms.name, dev->name);
1196 
1197         iph->version            = 4;
1198         iph->protocol           = IPPROTO_IPV6;
1199         iph->ihl                = 5;
1200         iph->ttl                = 64;
1201 
1202         dev->tstats = alloc_percpu(struct pcpu_tstats);
1203         if (!dev->tstats)
1204                 return -ENOMEM;
1205         dev_hold(dev);
1206         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1207         return 0;
1208 }
1209 
1210 static struct xfrm_tunnel sit_handler __read_mostly = {
1211         .handler        =       ipip6_rcv,
1212         .err_handler    =       ipip6_err,
1213         .priority       =       1,
1214 };
1215 
1216 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1217 {
1218         int prio;
1219 
1220         for (prio = 1; prio < 4; prio++) {
1221                 int h;
1222                 for (h = 0; h < HASH_SIZE; h++) {
1223                         struct ip_tunnel *t;
1224 
1225                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1226                         while (t != NULL) {
1227                                 unregister_netdevice_queue(t->dev, head);
1228                                 t = rtnl_dereference(t->next);
1229                         }
1230                 }
1231         }
1232 }
1233 
1234 static int __net_init sit_init_net(struct net *net)
1235 {
1236         struct sit_net *sitn = net_generic(net, sit_net_id);
1237         struct ip_tunnel *t;
1238         int err;
1239 
1240         sitn->tunnels[0] = sitn->tunnels_wc;
1241         sitn->tunnels[1] = sitn->tunnels_l;
1242         sitn->tunnels[2] = sitn->tunnels_r;
1243         sitn->tunnels[3] = sitn->tunnels_r_l;
1244 
1245         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1246                                            ipip6_tunnel_setup);
1247         if (!sitn->fb_tunnel_dev) {
1248                 err = -ENOMEM;
1249                 goto err_alloc_dev;
1250         }
1251         dev_net_set(sitn->fb_tunnel_dev, net);
1252 
1253         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1254         if (err)
1255                 goto err_dev_free;
1256 
1257         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1258 
1259         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1260                 goto err_reg_dev;
1261 
1262         t = netdev_priv(sitn->fb_tunnel_dev);
1263 
1264         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1265         return 0;
1266 
1267 err_reg_dev:
1268         dev_put(sitn->fb_tunnel_dev);
1269 err_dev_free:
1270         ipip6_dev_free(sitn->fb_tunnel_dev);
1271 err_alloc_dev:
1272         return err;
1273 }
1274 
1275 static void __net_exit sit_exit_net(struct net *net)
1276 {
1277         struct sit_net *sitn = net_generic(net, sit_net_id);
1278         LIST_HEAD(list);
1279 
1280         rtnl_lock();
1281         sit_destroy_tunnels(sitn, &list);
1282         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1283         unregister_netdevice_many(&list);
1284         rtnl_unlock();
1285 }
1286 
1287 static struct pernet_operations sit_net_ops = {
1288         .init = sit_init_net,
1289         .exit = sit_exit_net,
1290         .id   = &sit_net_id,
1291         .size = sizeof(struct sit_net),
1292 };
1293 
1294 static void __exit sit_cleanup(void)
1295 {
1296         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1297 
1298         unregister_pernet_device(&sit_net_ops);
1299         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1300 }
1301 
1302 static int __init sit_init(void)
1303 {
1304         int err;
1305 
1306         pr_info("IPv6 over IPv4 tunneling driver\n");
1307 
1308         err = register_pernet_device(&sit_net_ops);
1309         if (err < 0)
1310                 return err;
1311         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1312         if (err < 0) {
1313                 unregister_pernet_device(&sit_net_ops);
1314                 pr_info("%s: can't add protocol\n", __func__);
1315         }
1316         return err;
1317 }
1318 
1319 module_init(sit_init);
1320 module_exit(sit_cleanup);
1321 MODULE_LICENSE("GPL");
1322 MODULE_ALIAS_NETDEV("sit0");
1323 

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