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TOMOYO Linux Cross Reference
Linux/net/ipv6/ip6_tunnel.c

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  1 /*
  2  *      IPv6 tunneling device
  3  *      Linux INET6 implementation
  4  *
  5  *      Authors:
  6  *      Ville Nuorvala          <vnuorval@tcs.hut.fi>
  7  *      Yasuyuki Kozakai        <kozakai@linux-ipv6.org>
  8  *
  9  *      Based on:
 10  *      linux/net/ipv6/sit.c and linux/net/ipv4/ipip.c
 11  *
 12  *      RFC 2473
 13  *
 14  *      This program is free software; you can redistribute it and/or
 15  *      modify it under the terms of the GNU General Public License
 16  *      as published by the Free Software Foundation; either version
 17  *      2 of the License, or (at your option) any later version.
 18  *
 19  */
 20 
 21 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 22 
 23 #include <linux/module.h>
 24 #include <linux/capability.h>
 25 #include <linux/errno.h>
 26 #include <linux/types.h>
 27 #include <linux/sockios.h>
 28 #include <linux/icmp.h>
 29 #include <linux/if.h>
 30 #include <linux/in.h>
 31 #include <linux/ip.h>
 32 #include <linux/net.h>
 33 #include <linux/in6.h>
 34 #include <linux/netdevice.h>
 35 #include <linux/if_arp.h>
 36 #include <linux/icmpv6.h>
 37 #include <linux/init.h>
 38 #include <linux/route.h>
 39 #include <linux/rtnetlink.h>
 40 #include <linux/netfilter_ipv6.h>
 41 #include <linux/slab.h>
 42 #include <linux/hash.h>
 43 #include <linux/etherdevice.h>
 44 
 45 #include <asm/uaccess.h>
 46 #include <linux/atomic.h>
 47 
 48 #include <net/icmp.h>
 49 #include <net/ip.h>
 50 #include <net/ip_tunnels.h>
 51 #include <net/ipv6.h>
 52 #include <net/ip6_route.h>
 53 #include <net/addrconf.h>
 54 #include <net/ip6_tunnel.h>
 55 #include <net/xfrm.h>
 56 #include <net/dsfield.h>
 57 #include <net/inet_ecn.h>
 58 #include <net/net_namespace.h>
 59 #include <net/netns/generic.h>
 60 
 61 MODULE_AUTHOR("Ville Nuorvala");
 62 MODULE_DESCRIPTION("IPv6 tunneling device");
 63 MODULE_LICENSE("GPL");
 64 MODULE_ALIAS_RTNL_LINK("ip6tnl");
 65 MODULE_ALIAS_NETDEV("ip6tnl0");
 66 
 67 #define HASH_SIZE_SHIFT  5
 68 #define HASH_SIZE (1 << HASH_SIZE_SHIFT)
 69 
 70 static bool log_ecn_error = true;
 71 module_param(log_ecn_error, bool, 0644);
 72 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
 73 
 74 static u32 HASH(const struct in6_addr *addr1, const struct in6_addr *addr2)
 75 {
 76         u32 hash = ipv6_addr_hash(addr1) ^ ipv6_addr_hash(addr2);
 77 
 78         return hash_32(hash, HASH_SIZE_SHIFT);
 79 }
 80 
 81 static int ip6_tnl_dev_init(struct net_device *dev);
 82 static void ip6_tnl_dev_setup(struct net_device *dev);
 83 static struct rtnl_link_ops ip6_link_ops __read_mostly;
 84 
 85 static int ip6_tnl_net_id __read_mostly;
 86 struct ip6_tnl_net {
 87         /* the IPv6 tunnel fallback device */
 88         struct net_device *fb_tnl_dev;
 89         /* lists for storing tunnels in use */
 90         struct ip6_tnl __rcu *tnls_r_l[HASH_SIZE];
 91         struct ip6_tnl __rcu *tnls_wc[1];
 92         struct ip6_tnl __rcu **tnls[2];
 93 };
 94 
 95 static struct net_device_stats *ip6_get_stats(struct net_device *dev)
 96 {
 97         struct pcpu_sw_netstats tmp, sum = { 0 };
 98         int i;
 99 
100         for_each_possible_cpu(i) {
101                 unsigned int start;
102                 const struct pcpu_sw_netstats *tstats =
103                                                    per_cpu_ptr(dev->tstats, i);
104 
105                 do {
106                         start = u64_stats_fetch_begin_irq(&tstats->syncp);
107                         tmp.rx_packets = tstats->rx_packets;
108                         tmp.rx_bytes = tstats->rx_bytes;
109                         tmp.tx_packets = tstats->tx_packets;
110                         tmp.tx_bytes =  tstats->tx_bytes;
111                 } while (u64_stats_fetch_retry_irq(&tstats->syncp, start));
112 
113                 sum.rx_packets += tmp.rx_packets;
114                 sum.rx_bytes   += tmp.rx_bytes;
115                 sum.tx_packets += tmp.tx_packets;
116                 sum.tx_bytes   += tmp.tx_bytes;
117         }
118         dev->stats.rx_packets = sum.rx_packets;
119         dev->stats.rx_bytes   = sum.rx_bytes;
120         dev->stats.tx_packets = sum.tx_packets;
121         dev->stats.tx_bytes   = sum.tx_bytes;
122         return &dev->stats;
123 }
124 
125 /*
126  * Locking : hash tables are protected by RCU and RTNL
127  */
128 
129 static void ip6_tnl_per_cpu_dst_set(struct ip6_tnl_dst *idst,
130                                     struct dst_entry *dst)
131 {
132         write_seqlock_bh(&idst->lock);
133         dst_release(rcu_dereference_protected(
134                             idst->dst,
135                             lockdep_is_held(&idst->lock.lock)));
136         if (dst) {
137                 dst_hold(dst);
138                 idst->cookie = rt6_get_cookie((struct rt6_info *)dst);
139         } else {
140                 idst->cookie = 0;
141         }
142         rcu_assign_pointer(idst->dst, dst);
143         write_sequnlock_bh(&idst->lock);
144 }
145 
146 struct dst_entry *ip6_tnl_dst_get(struct ip6_tnl *t)
147 {
148         struct ip6_tnl_dst *idst;
149         struct dst_entry *dst;
150         unsigned int seq;
151         u32 cookie;
152 
153         idst = raw_cpu_ptr(t->dst_cache);
154 
155         rcu_read_lock();
156         do {
157                 seq = read_seqbegin(&idst->lock);
158                 dst = rcu_dereference(idst->dst);
159                 cookie = idst->cookie;
160         } while (read_seqretry(&idst->lock, seq));
161 
162         if (dst && !atomic_inc_not_zero(&dst->__refcnt))
163                 dst = NULL;
164         rcu_read_unlock();
165 
166         if (dst && dst->obsolete && !dst->ops->check(dst, cookie)) {
167                 ip6_tnl_per_cpu_dst_set(idst, NULL);
168                 dst_release(dst);
169                 dst = NULL;
170         }
171         return dst;
172 }
173 EXPORT_SYMBOL_GPL(ip6_tnl_dst_get);
174 
175 void ip6_tnl_dst_reset(struct ip6_tnl *t)
176 {
177         int i;
178 
179         for_each_possible_cpu(i)
180                 ip6_tnl_per_cpu_dst_set(per_cpu_ptr(t->dst_cache, i), NULL);
181 }
182 EXPORT_SYMBOL_GPL(ip6_tnl_dst_reset);
183 
184 void ip6_tnl_dst_set(struct ip6_tnl *t, struct dst_entry *dst)
185 {
186         ip6_tnl_per_cpu_dst_set(raw_cpu_ptr(t->dst_cache), dst);
187 
188 }
189 EXPORT_SYMBOL_GPL(ip6_tnl_dst_set);
190 
191 void ip6_tnl_dst_destroy(struct ip6_tnl *t)
192 {
193         if (!t->dst_cache)
194                 return;
195 
196         ip6_tnl_dst_reset(t);
197         free_percpu(t->dst_cache);
198 }
199 EXPORT_SYMBOL_GPL(ip6_tnl_dst_destroy);
200 
201 int ip6_tnl_dst_init(struct ip6_tnl *t)
202 {
203         int i;
204 
205         t->dst_cache = alloc_percpu(struct ip6_tnl_dst);
206         if (!t->dst_cache)
207                 return -ENOMEM;
208 
209         for_each_possible_cpu(i)
210                 seqlock_init(&per_cpu_ptr(t->dst_cache, i)->lock);
211 
212         return 0;
213 }
214 EXPORT_SYMBOL_GPL(ip6_tnl_dst_init);
215 
216 /**
217  * ip6_tnl_lookup - fetch tunnel matching the end-point addresses
218  *   @remote: the address of the tunnel exit-point
219  *   @local: the address of the tunnel entry-point
220  *
221  * Return:
222  *   tunnel matching given end-points if found,
223  *   else fallback tunnel if its device is up,
224  *   else %NULL
225  **/
226 
227 #define for_each_ip6_tunnel_rcu(start) \
228         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
229 
230 static struct ip6_tnl *
231 ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_addr *local)
232 {
233         unsigned int hash = HASH(remote, local);
234         struct ip6_tnl *t;
235         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
236         struct in6_addr any;
237 
238         for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
239                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
240                     ipv6_addr_equal(remote, &t->parms.raddr) &&
241                     (t->dev->flags & IFF_UP))
242                         return t;
243         }
244 
245         memset(&any, 0, sizeof(any));
246         hash = HASH(&any, local);
247         for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
248                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
249                     (t->dev->flags & IFF_UP))
250                         return t;
251         }
252 
253         hash = HASH(remote, &any);
254         for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
255                 if (ipv6_addr_equal(remote, &t->parms.raddr) &&
256                     (t->dev->flags & IFF_UP))
257                         return t;
258         }
259 
260         t = rcu_dereference(ip6n->tnls_wc[0]);
261         if (t && (t->dev->flags & IFF_UP))
262                 return t;
263 
264         return NULL;
265 }
266 
267 /**
268  * ip6_tnl_bucket - get head of list matching given tunnel parameters
269  *   @p: parameters containing tunnel end-points
270  *
271  * Description:
272  *   ip6_tnl_bucket() returns the head of the list matching the
273  *   &struct in6_addr entries laddr and raddr in @p.
274  *
275  * Return: head of IPv6 tunnel list
276  **/
277 
278 static struct ip6_tnl __rcu **
279 ip6_tnl_bucket(struct ip6_tnl_net *ip6n, const struct __ip6_tnl_parm *p)
280 {
281         const struct in6_addr *remote = &p->raddr;
282         const struct in6_addr *local = &p->laddr;
283         unsigned int h = 0;
284         int prio = 0;
285 
286         if (!ipv6_addr_any(remote) || !ipv6_addr_any(local)) {
287                 prio = 1;
288                 h = HASH(remote, local);
289         }
290         return &ip6n->tnls[prio][h];
291 }
292 
293 /**
294  * ip6_tnl_link - add tunnel to hash table
295  *   @t: tunnel to be added
296  **/
297 
298 static void
299 ip6_tnl_link(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
300 {
301         struct ip6_tnl __rcu **tp = ip6_tnl_bucket(ip6n, &t->parms);
302 
303         rcu_assign_pointer(t->next , rtnl_dereference(*tp));
304         rcu_assign_pointer(*tp, t);
305 }
306 
307 /**
308  * ip6_tnl_unlink - remove tunnel from hash table
309  *   @t: tunnel to be removed
310  **/
311 
312 static void
313 ip6_tnl_unlink(struct ip6_tnl_net *ip6n, struct ip6_tnl *t)
314 {
315         struct ip6_tnl __rcu **tp;
316         struct ip6_tnl *iter;
317 
318         for (tp = ip6_tnl_bucket(ip6n, &t->parms);
319              (iter = rtnl_dereference(*tp)) != NULL;
320              tp = &iter->next) {
321                 if (t == iter) {
322                         rcu_assign_pointer(*tp, t->next);
323                         break;
324                 }
325         }
326 }
327 
328 static void ip6_dev_free(struct net_device *dev)
329 {
330         struct ip6_tnl *t = netdev_priv(dev);
331 
332         ip6_tnl_dst_destroy(t);
333         free_percpu(dev->tstats);
334         free_netdev(dev);
335 }
336 
337 static int ip6_tnl_create2(struct net_device *dev)
338 {
339         struct ip6_tnl *t = netdev_priv(dev);
340         struct net *net = dev_net(dev);
341         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
342         int err;
343 
344         t = netdev_priv(dev);
345 
346         err = register_netdevice(dev);
347         if (err < 0)
348                 goto out;
349 
350         strcpy(t->parms.name, dev->name);
351         dev->rtnl_link_ops = &ip6_link_ops;
352 
353         dev_hold(dev);
354         ip6_tnl_link(ip6n, t);
355         return 0;
356 
357 out:
358         return err;
359 }
360 
361 /**
362  * ip6_tnl_create - create a new tunnel
363  *   @p: tunnel parameters
364  *   @pt: pointer to new tunnel
365  *
366  * Description:
367  *   Create tunnel matching given parameters.
368  *
369  * Return:
370  *   created tunnel or error pointer
371  **/
372 
373 static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
374 {
375         struct net_device *dev;
376         struct ip6_tnl *t;
377         char name[IFNAMSIZ];
378         int err = -ENOMEM;
379 
380         if (p->name[0])
381                 strlcpy(name, p->name, IFNAMSIZ);
382         else
383                 sprintf(name, "ip6tnl%%d");
384 
385         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
386                            ip6_tnl_dev_setup);
387         if (!dev)
388                 goto failed;
389 
390         dev_net_set(dev, net);
391 
392         t = netdev_priv(dev);
393         t->parms = *p;
394         t->net = dev_net(dev);
395         err = ip6_tnl_create2(dev);
396         if (err < 0)
397                 goto failed_free;
398 
399         return t;
400 
401 failed_free:
402         ip6_dev_free(dev);
403 failed:
404         return ERR_PTR(err);
405 }
406 
407 /**
408  * ip6_tnl_locate - find or create tunnel matching given parameters
409  *   @p: tunnel parameters
410  *   @create: != 0 if allowed to create new tunnel if no match found
411  *
412  * Description:
413  *   ip6_tnl_locate() first tries to locate an existing tunnel
414  *   based on @parms. If this is unsuccessful, but @create is set a new
415  *   tunnel device is created and registered for use.
416  *
417  * Return:
418  *   matching tunnel or error pointer
419  **/
420 
421 static struct ip6_tnl *ip6_tnl_locate(struct net *net,
422                 struct __ip6_tnl_parm *p, int create)
423 {
424         const struct in6_addr *remote = &p->raddr;
425         const struct in6_addr *local = &p->laddr;
426         struct ip6_tnl __rcu **tp;
427         struct ip6_tnl *t;
428         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
429 
430         for (tp = ip6_tnl_bucket(ip6n, p);
431              (t = rtnl_dereference(*tp)) != NULL;
432              tp = &t->next) {
433                 if (ipv6_addr_equal(local, &t->parms.laddr) &&
434                     ipv6_addr_equal(remote, &t->parms.raddr)) {
435                         if (create)
436                                 return ERR_PTR(-EEXIST);
437 
438                         return t;
439                 }
440         }
441         if (!create)
442                 return ERR_PTR(-ENODEV);
443         return ip6_tnl_create(net, p);
444 }
445 
446 /**
447  * ip6_tnl_dev_uninit - tunnel device uninitializer
448  *   @dev: the device to be destroyed
449  *
450  * Description:
451  *   ip6_tnl_dev_uninit() removes tunnel from its list
452  **/
453 
454 static void
455 ip6_tnl_dev_uninit(struct net_device *dev)
456 {
457         struct ip6_tnl *t = netdev_priv(dev);
458         struct net *net = t->net;
459         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
460 
461         if (dev == ip6n->fb_tnl_dev)
462                 RCU_INIT_POINTER(ip6n->tnls_wc[0], NULL);
463         else
464                 ip6_tnl_unlink(ip6n, t);
465         ip6_tnl_dst_reset(t);
466         dev_put(dev);
467 }
468 
469 /**
470  * parse_tvl_tnl_enc_lim - handle encapsulation limit option
471  *   @skb: received socket buffer
472  *
473  * Return:
474  *   0 if none was found,
475  *   else index to encapsulation limit
476  **/
477 
478 __u16 ip6_tnl_parse_tlv_enc_lim(struct sk_buff *skb, __u8 *raw)
479 {
480         const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) raw;
481         __u8 nexthdr = ipv6h->nexthdr;
482         __u16 off = sizeof(*ipv6h);
483 
484         while (ipv6_ext_hdr(nexthdr) && nexthdr != NEXTHDR_NONE) {
485                 __u16 optlen = 0;
486                 struct ipv6_opt_hdr *hdr;
487                 if (raw + off + sizeof(*hdr) > skb->data &&
488                     !pskb_may_pull(skb, raw - skb->data + off + sizeof (*hdr)))
489                         break;
490 
491                 hdr = (struct ipv6_opt_hdr *) (raw + off);
492                 if (nexthdr == NEXTHDR_FRAGMENT) {
493                         struct frag_hdr *frag_hdr = (struct frag_hdr *) hdr;
494                         if (frag_hdr->frag_off)
495                                 break;
496                         optlen = 8;
497                 } else if (nexthdr == NEXTHDR_AUTH) {
498                         optlen = (hdr->hdrlen + 2) << 2;
499                 } else {
500                         optlen = ipv6_optlen(hdr);
501                 }
502                 if (nexthdr == NEXTHDR_DEST) {
503                         __u16 i = off + 2;
504                         while (1) {
505                                 struct ipv6_tlv_tnl_enc_lim *tel;
506 
507                                 /* No more room for encapsulation limit */
508                                 if (i + sizeof (*tel) > off + optlen)
509                                         break;
510 
511                                 tel = (struct ipv6_tlv_tnl_enc_lim *) &raw[i];
512                                 /* return index of option if found and valid */
513                                 if (tel->type == IPV6_TLV_TNL_ENCAP_LIMIT &&
514                                     tel->length == 1)
515                                         return i;
516                                 /* else jump to next option */
517                                 if (tel->type)
518                                         i += tel->length + 2;
519                                 else
520                                         i++;
521                         }
522                 }
523                 nexthdr = hdr->nexthdr;
524                 off += optlen;
525         }
526         return 0;
527 }
528 EXPORT_SYMBOL(ip6_tnl_parse_tlv_enc_lim);
529 
530 /**
531  * ip6_tnl_err - tunnel error handler
532  *
533  * Description:
534  *   ip6_tnl_err() should handle errors in the tunnel according
535  *   to the specifications in RFC 2473.
536  **/
537 
538 static int
539 ip6_tnl_err(struct sk_buff *skb, __u8 ipproto, struct inet6_skb_parm *opt,
540             u8 *type, u8 *code, int *msg, __u32 *info, int offset)
541 {
542         const struct ipv6hdr *ipv6h = (const struct ipv6hdr *) skb->data;
543         struct ip6_tnl *t;
544         int rel_msg = 0;
545         u8 rel_type = ICMPV6_DEST_UNREACH;
546         u8 rel_code = ICMPV6_ADDR_UNREACH;
547         u8 tproto;
548         __u32 rel_info = 0;
549         __u16 len;
550         int err = -ENOENT;
551 
552         /* If the packet doesn't contain the original IPv6 header we are
553            in trouble since we might need the source address for further
554            processing of the error. */
555 
556         rcu_read_lock();
557         t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->daddr, &ipv6h->saddr);
558         if (!t)
559                 goto out;
560 
561         tproto = ACCESS_ONCE(t->parms.proto);
562         if (tproto != ipproto && tproto != 0)
563                 goto out;
564 
565         err = 0;
566 
567         switch (*type) {
568                 __u32 teli;
569                 struct ipv6_tlv_tnl_enc_lim *tel;
570                 __u32 mtu;
571         case ICMPV6_DEST_UNREACH:
572                 net_dbg_ratelimited("%s: Path to destination invalid or inactive!\n",
573                                     t->parms.name);
574                 rel_msg = 1;
575                 break;
576         case ICMPV6_TIME_EXCEED:
577                 if ((*code) == ICMPV6_EXC_HOPLIMIT) {
578                         net_dbg_ratelimited("%s: Too small hop limit or routing loop in tunnel!\n",
579                                             t->parms.name);
580                         rel_msg = 1;
581                 }
582                 break;
583         case ICMPV6_PARAMPROB:
584                 teli = 0;
585                 if ((*code) == ICMPV6_HDR_FIELD)
586                         teli = ip6_tnl_parse_tlv_enc_lim(skb, skb->data);
587 
588                 if (teli && teli == *info - 2) {
589                         tel = (struct ipv6_tlv_tnl_enc_lim *) &skb->data[teli];
590                         if (tel->encap_limit == 0) {
591                                 net_dbg_ratelimited("%s: Too small encapsulation limit or routing loop in tunnel!\n",
592                                                     t->parms.name);
593                                 rel_msg = 1;
594                         }
595                 } else {
596                         net_dbg_ratelimited("%s: Recipient unable to parse tunneled packet!\n",
597                                             t->parms.name);
598                 }
599                 break;
600         case ICMPV6_PKT_TOOBIG:
601                 mtu = *info - offset;
602                 if (mtu < IPV6_MIN_MTU)
603                         mtu = IPV6_MIN_MTU;
604                 t->dev->mtu = mtu;
605 
606                 len = sizeof(*ipv6h) + ntohs(ipv6h->payload_len);
607                 if (len > mtu) {
608                         rel_type = ICMPV6_PKT_TOOBIG;
609                         rel_code = 0;
610                         rel_info = mtu;
611                         rel_msg = 1;
612                 }
613                 break;
614         }
615 
616         *type = rel_type;
617         *code = rel_code;
618         *info = rel_info;
619         *msg = rel_msg;
620 
621 out:
622         rcu_read_unlock();
623         return err;
624 }
625 
626 static int
627 ip4ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
628            u8 type, u8 code, int offset, __be32 info)
629 {
630         int rel_msg = 0;
631         u8 rel_type = type;
632         u8 rel_code = code;
633         __u32 rel_info = ntohl(info);
634         int err;
635         struct sk_buff *skb2;
636         const struct iphdr *eiph;
637         struct rtable *rt;
638         struct flowi4 fl4;
639 
640         err = ip6_tnl_err(skb, IPPROTO_IPIP, opt, &rel_type, &rel_code,
641                           &rel_msg, &rel_info, offset);
642         if (err < 0)
643                 return err;
644 
645         if (rel_msg == 0)
646                 return 0;
647 
648         switch (rel_type) {
649         case ICMPV6_DEST_UNREACH:
650                 if (rel_code != ICMPV6_ADDR_UNREACH)
651                         return 0;
652                 rel_type = ICMP_DEST_UNREACH;
653                 rel_code = ICMP_HOST_UNREACH;
654                 break;
655         case ICMPV6_PKT_TOOBIG:
656                 if (rel_code != 0)
657                         return 0;
658                 rel_type = ICMP_DEST_UNREACH;
659                 rel_code = ICMP_FRAG_NEEDED;
660                 break;
661         case NDISC_REDIRECT:
662                 rel_type = ICMP_REDIRECT;
663                 rel_code = ICMP_REDIR_HOST;
664         default:
665                 return 0;
666         }
667 
668         if (!pskb_may_pull(skb, offset + sizeof(struct iphdr)))
669                 return 0;
670 
671         skb2 = skb_clone(skb, GFP_ATOMIC);
672         if (!skb2)
673                 return 0;
674 
675         skb_dst_drop(skb2);
676 
677         skb_pull(skb2, offset);
678         skb_reset_network_header(skb2);
679         eiph = ip_hdr(skb2);
680 
681         /* Try to guess incoming interface */
682         rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
683                                    eiph->saddr, 0,
684                                    0, 0,
685                                    IPPROTO_IPIP, RT_TOS(eiph->tos), 0);
686         if (IS_ERR(rt))
687                 goto out;
688 
689         skb2->dev = rt->dst.dev;
690 
691         /* route "incoming" packet */
692         if (rt->rt_flags & RTCF_LOCAL) {
693                 ip_rt_put(rt);
694                 rt = NULL;
695                 rt = ip_route_output_ports(dev_net(skb->dev), &fl4, NULL,
696                                            eiph->daddr, eiph->saddr,
697                                            0, 0,
698                                            IPPROTO_IPIP,
699                                            RT_TOS(eiph->tos), 0);
700                 if (IS_ERR(rt) ||
701                     rt->dst.dev->type != ARPHRD_TUNNEL) {
702                         if (!IS_ERR(rt))
703                                 ip_rt_put(rt);
704                         goto out;
705                 }
706                 skb_dst_set(skb2, &rt->dst);
707         } else {
708                 ip_rt_put(rt);
709                 if (ip_route_input(skb2, eiph->daddr, eiph->saddr, eiph->tos,
710                                    skb2->dev) ||
711                     skb_dst(skb2)->dev->type != ARPHRD_TUNNEL)
712                         goto out;
713         }
714 
715         /* change mtu on this route */
716         if (rel_type == ICMP_DEST_UNREACH && rel_code == ICMP_FRAG_NEEDED) {
717                 if (rel_info > dst_mtu(skb_dst(skb2)))
718                         goto out;
719 
720                 skb_dst(skb2)->ops->update_pmtu(skb_dst(skb2), NULL, skb2, rel_info);
721         }
722         if (rel_type == ICMP_REDIRECT)
723                 skb_dst(skb2)->ops->redirect(skb_dst(skb2), NULL, skb2);
724 
725         icmp_send(skb2, rel_type, rel_code, htonl(rel_info));
726 
727 out:
728         kfree_skb(skb2);
729         return 0;
730 }
731 
732 static int
733 ip6ip6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
734            u8 type, u8 code, int offset, __be32 info)
735 {
736         int rel_msg = 0;
737         u8 rel_type = type;
738         u8 rel_code = code;
739         __u32 rel_info = ntohl(info);
740         int err;
741 
742         err = ip6_tnl_err(skb, IPPROTO_IPV6, opt, &rel_type, &rel_code,
743                           &rel_msg, &rel_info, offset);
744         if (err < 0)
745                 return err;
746 
747         if (rel_msg && pskb_may_pull(skb, offset + sizeof(struct ipv6hdr))) {
748                 struct rt6_info *rt;
749                 struct sk_buff *skb2 = skb_clone(skb, GFP_ATOMIC);
750 
751                 if (!skb2)
752                         return 0;
753 
754                 skb_dst_drop(skb2);
755                 skb_pull(skb2, offset);
756                 skb_reset_network_header(skb2);
757 
758                 /* Try to guess incoming interface */
759                 rt = rt6_lookup(dev_net(skb->dev), &ipv6_hdr(skb2)->saddr,
760                                 NULL, 0, 0);
761 
762                 if (rt && rt->dst.dev)
763                         skb2->dev = rt->dst.dev;
764 
765                 icmpv6_send(skb2, rel_type, rel_code, rel_info);
766 
767                 ip6_rt_put(rt);
768 
769                 kfree_skb(skb2);
770         }
771 
772         return 0;
773 }
774 
775 static int ip4ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
776                                        const struct ipv6hdr *ipv6h,
777                                        struct sk_buff *skb)
778 {
779         __u8 dsfield = ipv6_get_dsfield(ipv6h) & ~INET_ECN_MASK;
780 
781         if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
782                 ipv4_change_dsfield(ip_hdr(skb), INET_ECN_MASK, dsfield);
783 
784         return IP6_ECN_decapsulate(ipv6h, skb);
785 }
786 
787 static int ip6ip6_dscp_ecn_decapsulate(const struct ip6_tnl *t,
788                                        const struct ipv6hdr *ipv6h,
789                                        struct sk_buff *skb)
790 {
791         if (t->parms.flags & IP6_TNL_F_RCV_DSCP_COPY)
792                 ipv6_copy_dscp(ipv6_get_dsfield(ipv6h), ipv6_hdr(skb));
793 
794         return IP6_ECN_decapsulate(ipv6h, skb);
795 }
796 
797 __u32 ip6_tnl_get_cap(struct ip6_tnl *t,
798                              const struct in6_addr *laddr,
799                              const struct in6_addr *raddr)
800 {
801         struct __ip6_tnl_parm *p = &t->parms;
802         int ltype = ipv6_addr_type(laddr);
803         int rtype = ipv6_addr_type(raddr);
804         __u32 flags = 0;
805 
806         if (ltype == IPV6_ADDR_ANY || rtype == IPV6_ADDR_ANY) {
807                 flags = IP6_TNL_F_CAP_PER_PACKET;
808         } else if (ltype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
809                    rtype & (IPV6_ADDR_UNICAST|IPV6_ADDR_MULTICAST) &&
810                    !((ltype|rtype) & IPV6_ADDR_LOOPBACK) &&
811                    (!((ltype|rtype) & IPV6_ADDR_LINKLOCAL) || p->link)) {
812                 if (ltype&IPV6_ADDR_UNICAST)
813                         flags |= IP6_TNL_F_CAP_XMIT;
814                 if (rtype&IPV6_ADDR_UNICAST)
815                         flags |= IP6_TNL_F_CAP_RCV;
816         }
817         return flags;
818 }
819 EXPORT_SYMBOL(ip6_tnl_get_cap);
820 
821 /* called with rcu_read_lock() */
822 int ip6_tnl_rcv_ctl(struct ip6_tnl *t,
823                                   const struct in6_addr *laddr,
824                                   const struct in6_addr *raddr)
825 {
826         struct __ip6_tnl_parm *p = &t->parms;
827         int ret = 0;
828         struct net *net = t->net;
829 
830         if ((p->flags & IP6_TNL_F_CAP_RCV) ||
831             ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
832              (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_RCV))) {
833                 struct net_device *ldev = NULL;
834 
835                 if (p->link)
836                         ldev = dev_get_by_index_rcu(net, p->link);
837 
838                 if ((ipv6_addr_is_multicast(laddr) ||
839                      likely(ipv6_chk_addr(net, laddr, ldev, 0))) &&
840                     likely(!ipv6_chk_addr(net, raddr, NULL, 0)))
841                         ret = 1;
842         }
843         return ret;
844 }
845 EXPORT_SYMBOL_GPL(ip6_tnl_rcv_ctl);
846 
847 /**
848  * ip6_tnl_rcv - decapsulate IPv6 packet and retransmit it locally
849  *   @skb: received socket buffer
850  *   @protocol: ethernet protocol ID
851  *   @dscp_ecn_decapsulate: the function to decapsulate DSCP code and ECN
852  *
853  * Return: 0
854  **/
855 
856 static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
857                        __u8 ipproto,
858                        int (*dscp_ecn_decapsulate)(const struct ip6_tnl *t,
859                                                    const struct ipv6hdr *ipv6h,
860                                                    struct sk_buff *skb))
861 {
862         struct ip6_tnl *t;
863         const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
864         u8 tproto;
865         int err;
866 
867         rcu_read_lock();
868         t = ip6_tnl_lookup(dev_net(skb->dev), &ipv6h->saddr, &ipv6h->daddr);
869         if (t) {
870                 struct pcpu_sw_netstats *tstats;
871 
872                 tproto = ACCESS_ONCE(t->parms.proto);
873                 if (tproto != ipproto && tproto != 0) {
874                         rcu_read_unlock();
875                         goto discard;
876                 }
877 
878                 if (!xfrm6_policy_check(NULL, XFRM_POLICY_IN, skb)) {
879                         rcu_read_unlock();
880                         goto discard;
881                 }
882 
883                 if (!ip6_tnl_rcv_ctl(t, &ipv6h->daddr, &ipv6h->saddr)) {
884                         t->dev->stats.rx_dropped++;
885                         rcu_read_unlock();
886                         goto discard;
887                 }
888                 skb->mac_header = skb->network_header;
889                 skb_reset_network_header(skb);
890                 skb->protocol = htons(protocol);
891                 memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
892 
893                 __skb_tunnel_rx(skb, t->dev, t->net);
894 
895                 err = dscp_ecn_decapsulate(t, ipv6h, skb);
896                 if (unlikely(err)) {
897                         if (log_ecn_error)
898                                 net_info_ratelimited("non-ECT from %pI6 with dsfield=%#x\n",
899                                                      &ipv6h->saddr,
900                                                      ipv6_get_dsfield(ipv6h));
901                         if (err > 1) {
902                                 ++t->dev->stats.rx_frame_errors;
903                                 ++t->dev->stats.rx_errors;
904                                 rcu_read_unlock();
905                                 goto discard;
906                         }
907                 }
908 
909                 tstats = this_cpu_ptr(t->dev->tstats);
910                 u64_stats_update_begin(&tstats->syncp);
911                 tstats->rx_packets++;
912                 tstats->rx_bytes += skb->len;
913                 u64_stats_update_end(&tstats->syncp);
914 
915                 netif_rx(skb);
916 
917                 rcu_read_unlock();
918                 return 0;
919         }
920         rcu_read_unlock();
921         return 1;
922 
923 discard:
924         kfree_skb(skb);
925         return 0;
926 }
927 
928 static int ip4ip6_rcv(struct sk_buff *skb)
929 {
930         return ip6_tnl_rcv(skb, ETH_P_IP, IPPROTO_IPIP,
931                            ip4ip6_dscp_ecn_decapsulate);
932 }
933 
934 static int ip6ip6_rcv(struct sk_buff *skb)
935 {
936         return ip6_tnl_rcv(skb, ETH_P_IPV6, IPPROTO_IPV6,
937                            ip6ip6_dscp_ecn_decapsulate);
938 }
939 
940 struct ipv6_tel_txoption {
941         struct ipv6_txoptions ops;
942         __u8 dst_opt[8];
943 };
944 
945 static void init_tel_txopt(struct ipv6_tel_txoption *opt, __u8 encap_limit)
946 {
947         memset(opt, 0, sizeof(struct ipv6_tel_txoption));
948 
949         opt->dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT;
950         opt->dst_opt[3] = 1;
951         opt->dst_opt[4] = encap_limit;
952         opt->dst_opt[5] = IPV6_TLV_PADN;
953         opt->dst_opt[6] = 1;
954 
955         opt->ops.dst0opt = (struct ipv6_opt_hdr *) opt->dst_opt;
956         opt->ops.opt_nflen = 8;
957 }
958 
959 /**
960  * ip6_tnl_addr_conflict - compare packet addresses to tunnel's own
961  *   @t: the outgoing tunnel device
962  *   @hdr: IPv6 header from the incoming packet
963  *
964  * Description:
965  *   Avoid trivial tunneling loop by checking that tunnel exit-point
966  *   doesn't match source of incoming packet.
967  *
968  * Return:
969  *   1 if conflict,
970  *   0 else
971  **/
972 
973 static inline bool
974 ip6_tnl_addr_conflict(const struct ip6_tnl *t, const struct ipv6hdr *hdr)
975 {
976         return ipv6_addr_equal(&t->parms.raddr, &hdr->saddr);
977 }
978 
979 int ip6_tnl_xmit_ctl(struct ip6_tnl *t,
980                      const struct in6_addr *laddr,
981                      const struct in6_addr *raddr)
982 {
983         struct __ip6_tnl_parm *p = &t->parms;
984         int ret = 0;
985         struct net *net = t->net;
986 
987         if ((p->flags & IP6_TNL_F_CAP_XMIT) ||
988             ((p->flags & IP6_TNL_F_CAP_PER_PACKET) &&
989              (ip6_tnl_get_cap(t, laddr, raddr) & IP6_TNL_F_CAP_XMIT))) {
990                 struct net_device *ldev = NULL;
991 
992                 rcu_read_lock();
993                 if (p->link)
994                         ldev = dev_get_by_index_rcu(net, p->link);
995 
996                 if (unlikely(!ipv6_chk_addr(net, laddr, ldev, 0)))
997                         pr_warn("%s xmit: Local address not yet configured!\n",
998                                 p->name);
999                 else if (!ipv6_addr_is_multicast(raddr) &&
1000                          unlikely(ipv6_chk_addr(net, raddr, NULL, 0)))
1001                         pr_warn("%s xmit: Routing loop! Remote address found on this node!\n",
1002                                 p->name);
1003                 else
1004                         ret = 1;
1005                 rcu_read_unlock();
1006         }
1007         return ret;
1008 }
1009 EXPORT_SYMBOL_GPL(ip6_tnl_xmit_ctl);
1010 
1011 /**
1012  * ip6_tnl_xmit2 - encapsulate packet and send
1013  *   @skb: the outgoing socket buffer
1014  *   @dev: the outgoing tunnel device
1015  *   @dsfield: dscp code for outer header
1016  *   @fl: flow of tunneled packet
1017  *   @encap_limit: encapsulation limit
1018  *   @pmtu: Path MTU is stored if packet is too big
1019  *
1020  * Description:
1021  *   Build new header and do some sanity checks on the packet before sending
1022  *   it.
1023  *
1024  * Return:
1025  *   0 on success
1026  *   -1 fail
1027  *   %-EMSGSIZE message too big. return mtu in this case.
1028  **/
1029 
1030 static int ip6_tnl_xmit2(struct sk_buff *skb,
1031                          struct net_device *dev,
1032                          __u8 dsfield,
1033                          struct flowi6 *fl6,
1034                          int encap_limit,
1035                          __u32 *pmtu)
1036 {
1037         struct ip6_tnl *t = netdev_priv(dev);
1038         struct net *net = t->net;
1039         struct net_device_stats *stats = &t->dev->stats;
1040         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
1041         struct ipv6_tel_txoption opt;
1042         struct dst_entry *dst = NULL, *ndst = NULL;
1043         struct net_device *tdev;
1044         int mtu;
1045         unsigned int max_headroom = sizeof(struct ipv6hdr);
1046         u8 proto;
1047         int err = -1;
1048 
1049         /* NBMA tunnel */
1050         if (ipv6_addr_any(&t->parms.raddr)) {
1051                 struct in6_addr *addr6;
1052                 struct neighbour *neigh;
1053                 int addr_type;
1054 
1055                 if (!skb_dst(skb))
1056                         goto tx_err_link_failure;
1057 
1058                 neigh = dst_neigh_lookup(skb_dst(skb),
1059                                          &ipv6_hdr(skb)->daddr);
1060                 if (!neigh)
1061                         goto tx_err_link_failure;
1062 
1063                 addr6 = (struct in6_addr *)&neigh->primary_key;
1064                 addr_type = ipv6_addr_type(addr6);
1065 
1066                 if (addr_type == IPV6_ADDR_ANY)
1067                         addr6 = &ipv6_hdr(skb)->daddr;
1068 
1069                 memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
1070                 neigh_release(neigh);
1071         } else if (!fl6->flowi6_mark)
1072                 dst = ip6_tnl_dst_get(t);
1073 
1074         if (!ip6_tnl_xmit_ctl(t, &fl6->saddr, &fl6->daddr))
1075                 goto tx_err_link_failure;
1076 
1077         if (!dst) {
1078                 dst = ip6_route_output(net, NULL, fl6);
1079 
1080                 if (dst->error)
1081                         goto tx_err_link_failure;
1082                 dst = xfrm_lookup(net, dst, flowi6_to_flowi(fl6), NULL, 0);
1083                 if (IS_ERR(dst)) {
1084                         err = PTR_ERR(dst);
1085                         dst = NULL;
1086                         goto tx_err_link_failure;
1087                 }
1088                 ndst = dst;
1089         }
1090 
1091         tdev = dst->dev;
1092 
1093         if (tdev == dev) {
1094                 stats->collisions++;
1095                 net_warn_ratelimited("%s: Local routing loop detected!\n",
1096                                      t->parms.name);
1097                 goto tx_err_dst_release;
1098         }
1099         mtu = dst_mtu(dst) - sizeof(*ipv6h);
1100         if (encap_limit >= 0) {
1101                 max_headroom += 8;
1102                 mtu -= 8;
1103         }
1104         if (mtu < IPV6_MIN_MTU)
1105                 mtu = IPV6_MIN_MTU;
1106         if (skb_dst(skb))
1107                 skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
1108         if (skb->len > mtu) {
1109                 *pmtu = mtu;
1110                 err = -EMSGSIZE;
1111                 goto tx_err_dst_release;
1112         }
1113 
1114         skb_scrub_packet(skb, !net_eq(t->net, dev_net(dev)));
1115 
1116         /*
1117          * Okay, now see if we can stuff it in the buffer as-is.
1118          */
1119         max_headroom += LL_RESERVED_SPACE(tdev);
1120 
1121         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1122             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1123                 struct sk_buff *new_skb;
1124 
1125                 new_skb = skb_realloc_headroom(skb, max_headroom);
1126                 if (!new_skb)
1127                         goto tx_err_dst_release;
1128 
1129                 if (skb->sk)
1130                         skb_set_owner_w(new_skb, skb->sk);
1131                 consume_skb(skb);
1132                 skb = new_skb;
1133         }
1134 
1135         if (!fl6->flowi6_mark && ndst)
1136                 ip6_tnl_dst_set(t, ndst);
1137         skb_dst_set(skb, dst);
1138 
1139         skb->transport_header = skb->network_header;
1140 
1141         proto = fl6->flowi6_proto;
1142         if (encap_limit >= 0) {
1143                 init_tel_txopt(&opt, encap_limit);
1144                 ipv6_push_nfrag_opts(skb, &opt.ops, &proto, NULL);
1145         }
1146 
1147         if (likely(!skb->encapsulation)) {
1148                 skb_reset_inner_headers(skb);
1149                 skb->encapsulation = 1;
1150         }
1151 
1152         skb_push(skb, sizeof(struct ipv6hdr));
1153         skb_reset_network_header(skb);
1154         ipv6h = ipv6_hdr(skb);
1155         ip6_flow_hdr(ipv6h, INET_ECN_encapsulate(0, dsfield),
1156                      ip6_make_flowlabel(net, skb, fl6->flowlabel, true, fl6));
1157         ipv6h->hop_limit = t->parms.hop_limit;
1158         ipv6h->nexthdr = proto;
1159         ipv6h->saddr = fl6->saddr;
1160         ipv6h->daddr = fl6->daddr;
1161         ip6tunnel_xmit(NULL, skb, dev);
1162         return 0;
1163 tx_err_link_failure:
1164         stats->tx_carrier_errors++;
1165         dst_link_failure(skb);
1166 tx_err_dst_release:
1167         dst_release(dst);
1168         return err;
1169 }
1170 
1171 static inline int
1172 ip4ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1173 {
1174         struct ip6_tnl *t = netdev_priv(dev);
1175         const struct iphdr  *iph = ip_hdr(skb);
1176         int encap_limit = -1;
1177         struct flowi6 fl6;
1178         __u8 dsfield;
1179         __u32 mtu;
1180         u8 tproto;
1181         int err;
1182 
1183         tproto = ACCESS_ONCE(t->parms.proto);
1184         if (tproto != IPPROTO_IPIP && tproto != 0)
1185                 return -1;
1186 
1187         if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1188                 encap_limit = t->parms.encap_limit;
1189 
1190         memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
1191         fl6.flowi6_proto = IPPROTO_IPIP;
1192 
1193         dsfield = ipv4_get_dsfield(iph);
1194 
1195         if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1196                 fl6.flowlabel |= htonl((__u32)iph->tos << IPV6_TCLASS_SHIFT)
1197                                           & IPV6_TCLASS_MASK;
1198         if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1199                 fl6.flowi6_mark = skb->mark;
1200 
1201         err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1202         if (err != 0) {
1203                 /* XXX: send ICMP error even if DF is not set. */
1204                 if (err == -EMSGSIZE)
1205                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
1206                                   htonl(mtu));
1207                 return -1;
1208         }
1209 
1210         return 0;
1211 }
1212 
1213 static inline int
1214 ip6ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1215 {
1216         struct ip6_tnl *t = netdev_priv(dev);
1217         struct ipv6hdr *ipv6h = ipv6_hdr(skb);
1218         int encap_limit = -1;
1219         __u16 offset;
1220         struct flowi6 fl6;
1221         __u8 dsfield;
1222         __u32 mtu;
1223         u8 tproto;
1224         int err;
1225 
1226         tproto = ACCESS_ONCE(t->parms.proto);
1227         if ((tproto != IPPROTO_IPV6 && tproto != 0) ||
1228             ip6_tnl_addr_conflict(t, ipv6h))
1229                 return -1;
1230 
1231         offset = ip6_tnl_parse_tlv_enc_lim(skb, skb_network_header(skb));
1232         if (offset > 0) {
1233                 struct ipv6_tlv_tnl_enc_lim *tel;
1234                 tel = (struct ipv6_tlv_tnl_enc_lim *)&skb_network_header(skb)[offset];
1235                 if (tel->encap_limit == 0) {
1236                         icmpv6_send(skb, ICMPV6_PARAMPROB,
1237                                     ICMPV6_HDR_FIELD, offset + 2);
1238                         return -1;
1239                 }
1240                 encap_limit = tel->encap_limit - 1;
1241         } else if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1242                 encap_limit = t->parms.encap_limit;
1243 
1244         memcpy(&fl6, &t->fl.u.ip6, sizeof(fl6));
1245         fl6.flowi6_proto = IPPROTO_IPV6;
1246 
1247         dsfield = ipv6_get_dsfield(ipv6h);
1248         if (t->parms.flags & IP6_TNL_F_USE_ORIG_TCLASS)
1249                 fl6.flowlabel |= (*(__be32 *) ipv6h & IPV6_TCLASS_MASK);
1250         if (t->parms.flags & IP6_TNL_F_USE_ORIG_FLOWLABEL)
1251                 fl6.flowlabel |= ip6_flowlabel(ipv6h);
1252         if (t->parms.flags & IP6_TNL_F_USE_ORIG_FWMARK)
1253                 fl6.flowi6_mark = skb->mark;
1254 
1255         err = ip6_tnl_xmit2(skb, dev, dsfield, &fl6, encap_limit, &mtu);
1256         if (err != 0) {
1257                 if (err == -EMSGSIZE)
1258                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1259                 return -1;
1260         }
1261 
1262         return 0;
1263 }
1264 
1265 static netdev_tx_t
1266 ip6_tnl_xmit(struct sk_buff *skb, struct net_device *dev)
1267 {
1268         struct ip6_tnl *t = netdev_priv(dev);
1269         struct net_device_stats *stats = &t->dev->stats;
1270         int ret;
1271 
1272         switch (skb->protocol) {
1273         case htons(ETH_P_IP):
1274                 ret = ip4ip6_tnl_xmit(skb, dev);
1275                 break;
1276         case htons(ETH_P_IPV6):
1277                 ret = ip6ip6_tnl_xmit(skb, dev);
1278                 break;
1279         default:
1280                 goto tx_err;
1281         }
1282 
1283         if (ret < 0)
1284                 goto tx_err;
1285 
1286         return NETDEV_TX_OK;
1287 
1288 tx_err:
1289         stats->tx_errors++;
1290         stats->tx_dropped++;
1291         kfree_skb(skb);
1292         return NETDEV_TX_OK;
1293 }
1294 
1295 static void ip6_tnl_link_config(struct ip6_tnl *t)
1296 {
1297         struct net_device *dev = t->dev;
1298         struct __ip6_tnl_parm *p = &t->parms;
1299         struct flowi6 *fl6 = &t->fl.u.ip6;
1300 
1301         memcpy(dev->dev_addr, &p->laddr, sizeof(struct in6_addr));
1302         memcpy(dev->broadcast, &p->raddr, sizeof(struct in6_addr));
1303 
1304         /* Set up flowi template */
1305         fl6->saddr = p->laddr;
1306         fl6->daddr = p->raddr;
1307         fl6->flowi6_oif = p->link;
1308         fl6->flowlabel = 0;
1309 
1310         if (!(p->flags&IP6_TNL_F_USE_ORIG_TCLASS))
1311                 fl6->flowlabel |= IPV6_TCLASS_MASK & p->flowinfo;
1312         if (!(p->flags&IP6_TNL_F_USE_ORIG_FLOWLABEL))
1313                 fl6->flowlabel |= IPV6_FLOWLABEL_MASK & p->flowinfo;
1314 
1315         p->flags &= ~(IP6_TNL_F_CAP_XMIT|IP6_TNL_F_CAP_RCV|IP6_TNL_F_CAP_PER_PACKET);
1316         p->flags |= ip6_tnl_get_cap(t, &p->laddr, &p->raddr);
1317 
1318         if (p->flags&IP6_TNL_F_CAP_XMIT && p->flags&IP6_TNL_F_CAP_RCV)
1319                 dev->flags |= IFF_POINTOPOINT;
1320         else
1321                 dev->flags &= ~IFF_POINTOPOINT;
1322 
1323         if (p->flags & IP6_TNL_F_CAP_XMIT) {
1324                 int strict = (ipv6_addr_type(&p->raddr) &
1325                               (IPV6_ADDR_MULTICAST|IPV6_ADDR_LINKLOCAL));
1326 
1327                 struct rt6_info *rt = rt6_lookup(t->net,
1328                                                  &p->raddr, &p->laddr,
1329                                                  p->link, strict);
1330 
1331                 if (!rt)
1332                         return;
1333 
1334                 if (rt->dst.dev) {
1335                         dev->hard_header_len = rt->dst.dev->hard_header_len +
1336                                 sizeof(struct ipv6hdr);
1337 
1338                         dev->mtu = rt->dst.dev->mtu - sizeof(struct ipv6hdr);
1339                         if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1340                                 dev->mtu -= 8;
1341 
1342                         if (dev->mtu < IPV6_MIN_MTU)
1343                                 dev->mtu = IPV6_MIN_MTU;
1344                 }
1345                 ip6_rt_put(rt);
1346         }
1347 }
1348 
1349 /**
1350  * ip6_tnl_change - update the tunnel parameters
1351  *   @t: tunnel to be changed
1352  *   @p: tunnel configuration parameters
1353  *
1354  * Description:
1355  *   ip6_tnl_change() updates the tunnel parameters
1356  **/
1357 
1358 static int
1359 ip6_tnl_change(struct ip6_tnl *t, const struct __ip6_tnl_parm *p)
1360 {
1361         t->parms.laddr = p->laddr;
1362         t->parms.raddr = p->raddr;
1363         t->parms.flags = p->flags;
1364         t->parms.hop_limit = p->hop_limit;
1365         t->parms.encap_limit = p->encap_limit;
1366         t->parms.flowinfo = p->flowinfo;
1367         t->parms.link = p->link;
1368         t->parms.proto = p->proto;
1369         ip6_tnl_dst_reset(t);
1370         ip6_tnl_link_config(t);
1371         return 0;
1372 }
1373 
1374 static int ip6_tnl_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
1375 {
1376         struct net *net = t->net;
1377         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1378         int err;
1379 
1380         ip6_tnl_unlink(ip6n, t);
1381         synchronize_net();
1382         err = ip6_tnl_change(t, p);
1383         ip6_tnl_link(ip6n, t);
1384         netdev_state_change(t->dev);
1385         return err;
1386 }
1387 
1388 static int ip6_tnl0_update(struct ip6_tnl *t, struct __ip6_tnl_parm *p)
1389 {
1390         /* for default tnl0 device allow to change only the proto */
1391         t->parms.proto = p->proto;
1392         netdev_state_change(t->dev);
1393         return 0;
1394 }
1395 
1396 static void
1397 ip6_tnl_parm_from_user(struct __ip6_tnl_parm *p, const struct ip6_tnl_parm *u)
1398 {
1399         p->laddr = u->laddr;
1400         p->raddr = u->raddr;
1401         p->flags = u->flags;
1402         p->hop_limit = u->hop_limit;
1403         p->encap_limit = u->encap_limit;
1404         p->flowinfo = u->flowinfo;
1405         p->link = u->link;
1406         p->proto = u->proto;
1407         memcpy(p->name, u->name, sizeof(u->name));
1408 }
1409 
1410 static void
1411 ip6_tnl_parm_to_user(struct ip6_tnl_parm *u, const struct __ip6_tnl_parm *p)
1412 {
1413         u->laddr = p->laddr;
1414         u->raddr = p->raddr;
1415         u->flags = p->flags;
1416         u->hop_limit = p->hop_limit;
1417         u->encap_limit = p->encap_limit;
1418         u->flowinfo = p->flowinfo;
1419         u->link = p->link;
1420         u->proto = p->proto;
1421         memcpy(u->name, p->name, sizeof(u->name));
1422 }
1423 
1424 /**
1425  * ip6_tnl_ioctl - configure ipv6 tunnels from userspace
1426  *   @dev: virtual device associated with tunnel
1427  *   @ifr: parameters passed from userspace
1428  *   @cmd: command to be performed
1429  *
1430  * Description:
1431  *   ip6_tnl_ioctl() is used for managing IPv6 tunnels
1432  *   from userspace.
1433  *
1434  *   The possible commands are the following:
1435  *     %SIOCGETTUNNEL: get tunnel parameters for device
1436  *     %SIOCADDTUNNEL: add tunnel matching given tunnel parameters
1437  *     %SIOCCHGTUNNEL: change tunnel parameters to those given
1438  *     %SIOCDELTUNNEL: delete tunnel
1439  *
1440  *   The fallback device "ip6tnl0", created during module
1441  *   initialization, can be used for creating other tunnel devices.
1442  *
1443  * Return:
1444  *   0 on success,
1445  *   %-EFAULT if unable to copy data to or from userspace,
1446  *   %-EPERM if current process hasn't %CAP_NET_ADMIN set
1447  *   %-EINVAL if passed tunnel parameters are invalid,
1448  *   %-EEXIST if changing a tunnel's parameters would cause a conflict
1449  *   %-ENODEV if attempting to change or delete a nonexisting device
1450  **/
1451 
1452 static int
1453 ip6_tnl_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
1454 {
1455         int err = 0;
1456         struct ip6_tnl_parm p;
1457         struct __ip6_tnl_parm p1;
1458         struct ip6_tnl *t = netdev_priv(dev);
1459         struct net *net = t->net;
1460         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1461 
1462         switch (cmd) {
1463         case SIOCGETTUNNEL:
1464                 if (dev == ip6n->fb_tnl_dev) {
1465                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1466                                 err = -EFAULT;
1467                                 break;
1468                         }
1469                         ip6_tnl_parm_from_user(&p1, &p);
1470                         t = ip6_tnl_locate(net, &p1, 0);
1471                         if (IS_ERR(t))
1472                                 t = netdev_priv(dev);
1473                 } else {
1474                         memset(&p, 0, sizeof(p));
1475                 }
1476                 ip6_tnl_parm_to_user(&p, &t->parms);
1477                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p))) {
1478                         err = -EFAULT;
1479                 }
1480                 break;
1481         case SIOCADDTUNNEL:
1482         case SIOCCHGTUNNEL:
1483                 err = -EPERM;
1484                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1485                         break;
1486                 err = -EFAULT;
1487                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1488                         break;
1489                 err = -EINVAL;
1490                 if (p.proto != IPPROTO_IPV6 && p.proto != IPPROTO_IPIP &&
1491                     p.proto != 0)
1492                         break;
1493                 ip6_tnl_parm_from_user(&p1, &p);
1494                 t = ip6_tnl_locate(net, &p1, cmd == SIOCADDTUNNEL);
1495                 if (cmd == SIOCCHGTUNNEL) {
1496                         if (!IS_ERR(t)) {
1497                                 if (t->dev != dev) {
1498                                         err = -EEXIST;
1499                                         break;
1500                                 }
1501                         } else
1502                                 t = netdev_priv(dev);
1503                         if (dev == ip6n->fb_tnl_dev)
1504                                 err = ip6_tnl0_update(t, &p1);
1505                         else
1506                                 err = ip6_tnl_update(t, &p1);
1507                 }
1508                 if (!IS_ERR(t)) {
1509                         err = 0;
1510                         ip6_tnl_parm_to_user(&p, &t->parms);
1511                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
1512                                 err = -EFAULT;
1513 
1514                 } else {
1515                         err = PTR_ERR(t);
1516                 }
1517                 break;
1518         case SIOCDELTUNNEL:
1519                 err = -EPERM;
1520                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1521                         break;
1522 
1523                 if (dev == ip6n->fb_tnl_dev) {
1524                         err = -EFAULT;
1525                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1526                                 break;
1527                         err = -ENOENT;
1528                         ip6_tnl_parm_from_user(&p1, &p);
1529                         t = ip6_tnl_locate(net, &p1, 0);
1530                         if (IS_ERR(t))
1531                                 break;
1532                         err = -EPERM;
1533                         if (t->dev == ip6n->fb_tnl_dev)
1534                                 break;
1535                         dev = t->dev;
1536                 }
1537                 err = 0;
1538                 unregister_netdevice(dev);
1539                 break;
1540         default:
1541                 err = -EINVAL;
1542         }
1543         return err;
1544 }
1545 
1546 /**
1547  * ip6_tnl_change_mtu - change mtu manually for tunnel device
1548  *   @dev: virtual device associated with tunnel
1549  *   @new_mtu: the new mtu
1550  *
1551  * Return:
1552  *   0 on success,
1553  *   %-EINVAL if mtu too small
1554  **/
1555 
1556 static int
1557 ip6_tnl_change_mtu(struct net_device *dev, int new_mtu)
1558 {
1559         struct ip6_tnl *tnl = netdev_priv(dev);
1560 
1561         if (tnl->parms.proto == IPPROTO_IPIP) {
1562                 if (new_mtu < 68)
1563                         return -EINVAL;
1564         } else {
1565                 if (new_mtu < IPV6_MIN_MTU)
1566                         return -EINVAL;
1567         }
1568         if (new_mtu > 0xFFF8 - dev->hard_header_len)
1569                 return -EINVAL;
1570         dev->mtu = new_mtu;
1571         return 0;
1572 }
1573 
1574 int ip6_tnl_get_iflink(const struct net_device *dev)
1575 {
1576         struct ip6_tnl *t = netdev_priv(dev);
1577 
1578         return t->parms.link;
1579 }
1580 EXPORT_SYMBOL(ip6_tnl_get_iflink);
1581 
1582 static const struct net_device_ops ip6_tnl_netdev_ops = {
1583         .ndo_init       = ip6_tnl_dev_init,
1584         .ndo_uninit     = ip6_tnl_dev_uninit,
1585         .ndo_start_xmit = ip6_tnl_xmit,
1586         .ndo_do_ioctl   = ip6_tnl_ioctl,
1587         .ndo_change_mtu = ip6_tnl_change_mtu,
1588         .ndo_get_stats  = ip6_get_stats,
1589         .ndo_get_iflink = ip6_tnl_get_iflink,
1590 };
1591 
1592 
1593 /**
1594  * ip6_tnl_dev_setup - setup virtual tunnel device
1595  *   @dev: virtual device associated with tunnel
1596  *
1597  * Description:
1598  *   Initialize function pointers and device parameters
1599  **/
1600 
1601 static void ip6_tnl_dev_setup(struct net_device *dev)
1602 {
1603         struct ip6_tnl *t;
1604 
1605         dev->netdev_ops = &ip6_tnl_netdev_ops;
1606         dev->destructor = ip6_dev_free;
1607 
1608         dev->type = ARPHRD_TUNNEL6;
1609         dev->hard_header_len = LL_MAX_HEADER + sizeof(struct ipv6hdr);
1610         dev->mtu = ETH_DATA_LEN - sizeof(struct ipv6hdr);
1611         t = netdev_priv(dev);
1612         if (!(t->parms.flags & IP6_TNL_F_IGN_ENCAP_LIMIT))
1613                 dev->mtu -= 8;
1614         dev->flags |= IFF_NOARP;
1615         dev->addr_len = sizeof(struct in6_addr);
1616         netif_keep_dst(dev);
1617         /* This perm addr will be used as interface identifier by IPv6 */
1618         dev->addr_assign_type = NET_ADDR_RANDOM;
1619         eth_random_addr(dev->perm_addr);
1620 }
1621 
1622 
1623 /**
1624  * ip6_tnl_dev_init_gen - general initializer for all tunnel devices
1625  *   @dev: virtual device associated with tunnel
1626  **/
1627 
1628 static inline int
1629 ip6_tnl_dev_init_gen(struct net_device *dev)
1630 {
1631         struct ip6_tnl *t = netdev_priv(dev);
1632         int ret;
1633 
1634         t->dev = dev;
1635         t->net = dev_net(dev);
1636         dev->tstats = netdev_alloc_pcpu_stats(struct pcpu_sw_netstats);
1637         if (!dev->tstats)
1638                 return -ENOMEM;
1639 
1640         ret = ip6_tnl_dst_init(t);
1641         if (ret) {
1642                 free_percpu(dev->tstats);
1643                 dev->tstats = NULL;
1644                 return ret;
1645         }
1646 
1647         return 0;
1648 }
1649 
1650 /**
1651  * ip6_tnl_dev_init - initializer for all non fallback tunnel devices
1652  *   @dev: virtual device associated with tunnel
1653  **/
1654 
1655 static int ip6_tnl_dev_init(struct net_device *dev)
1656 {
1657         struct ip6_tnl *t = netdev_priv(dev);
1658         int err = ip6_tnl_dev_init_gen(dev);
1659 
1660         if (err)
1661                 return err;
1662         ip6_tnl_link_config(t);
1663         return 0;
1664 }
1665 
1666 /**
1667  * ip6_fb_tnl_dev_init - initializer for fallback tunnel device
1668  *   @dev: fallback device
1669  *
1670  * Return: 0
1671  **/
1672 
1673 static int __net_init ip6_fb_tnl_dev_init(struct net_device *dev)
1674 {
1675         struct ip6_tnl *t = netdev_priv(dev);
1676         struct net *net = dev_net(dev);
1677         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1678 
1679         t->parms.proto = IPPROTO_IPV6;
1680         dev_hold(dev);
1681 
1682         rcu_assign_pointer(ip6n->tnls_wc[0], t);
1683         return 0;
1684 }
1685 
1686 static int ip6_tnl_validate(struct nlattr *tb[], struct nlattr *data[])
1687 {
1688         u8 proto;
1689 
1690         if (!data || !data[IFLA_IPTUN_PROTO])
1691                 return 0;
1692 
1693         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1694         if (proto != IPPROTO_IPV6 &&
1695             proto != IPPROTO_IPIP &&
1696             proto != 0)
1697                 return -EINVAL;
1698 
1699         return 0;
1700 }
1701 
1702 static void ip6_tnl_netlink_parms(struct nlattr *data[],
1703                                   struct __ip6_tnl_parm *parms)
1704 {
1705         memset(parms, 0, sizeof(*parms));
1706 
1707         if (!data)
1708                 return;
1709 
1710         if (data[IFLA_IPTUN_LINK])
1711                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1712 
1713         if (data[IFLA_IPTUN_LOCAL])
1714                 parms->laddr = nla_get_in6_addr(data[IFLA_IPTUN_LOCAL]);
1715 
1716         if (data[IFLA_IPTUN_REMOTE])
1717                 parms->raddr = nla_get_in6_addr(data[IFLA_IPTUN_REMOTE]);
1718 
1719         if (data[IFLA_IPTUN_TTL])
1720                 parms->hop_limit = nla_get_u8(data[IFLA_IPTUN_TTL]);
1721 
1722         if (data[IFLA_IPTUN_ENCAP_LIMIT])
1723                 parms->encap_limit = nla_get_u8(data[IFLA_IPTUN_ENCAP_LIMIT]);
1724 
1725         if (data[IFLA_IPTUN_FLOWINFO])
1726                 parms->flowinfo = nla_get_be32(data[IFLA_IPTUN_FLOWINFO]);
1727 
1728         if (data[IFLA_IPTUN_FLAGS])
1729                 parms->flags = nla_get_u32(data[IFLA_IPTUN_FLAGS]);
1730 
1731         if (data[IFLA_IPTUN_PROTO])
1732                 parms->proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1733 }
1734 
1735 static int ip6_tnl_newlink(struct net *src_net, struct net_device *dev,
1736                            struct nlattr *tb[], struct nlattr *data[])
1737 {
1738         struct net *net = dev_net(dev);
1739         struct ip6_tnl *nt, *t;
1740 
1741         nt = netdev_priv(dev);
1742         ip6_tnl_netlink_parms(data, &nt->parms);
1743 
1744         t = ip6_tnl_locate(net, &nt->parms, 0);
1745         if (!IS_ERR(t))
1746                 return -EEXIST;
1747 
1748         return ip6_tnl_create2(dev);
1749 }
1750 
1751 static int ip6_tnl_changelink(struct net_device *dev, struct nlattr *tb[],
1752                               struct nlattr *data[])
1753 {
1754         struct ip6_tnl *t = netdev_priv(dev);
1755         struct __ip6_tnl_parm p;
1756         struct net *net = t->net;
1757         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1758 
1759         if (dev == ip6n->fb_tnl_dev)
1760                 return -EINVAL;
1761 
1762         ip6_tnl_netlink_parms(data, &p);
1763 
1764         t = ip6_tnl_locate(net, &p, 0);
1765         if (!IS_ERR(t)) {
1766                 if (t->dev != dev)
1767                         return -EEXIST;
1768         } else
1769                 t = netdev_priv(dev);
1770 
1771         return ip6_tnl_update(t, &p);
1772 }
1773 
1774 static void ip6_tnl_dellink(struct net_device *dev, struct list_head *head)
1775 {
1776         struct net *net = dev_net(dev);
1777         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1778 
1779         if (dev != ip6n->fb_tnl_dev)
1780                 unregister_netdevice_queue(dev, head);
1781 }
1782 
1783 static size_t ip6_tnl_get_size(const struct net_device *dev)
1784 {
1785         return
1786                 /* IFLA_IPTUN_LINK */
1787                 nla_total_size(4) +
1788                 /* IFLA_IPTUN_LOCAL */
1789                 nla_total_size(sizeof(struct in6_addr)) +
1790                 /* IFLA_IPTUN_REMOTE */
1791                 nla_total_size(sizeof(struct in6_addr)) +
1792                 /* IFLA_IPTUN_TTL */
1793                 nla_total_size(1) +
1794                 /* IFLA_IPTUN_ENCAP_LIMIT */
1795                 nla_total_size(1) +
1796                 /* IFLA_IPTUN_FLOWINFO */
1797                 nla_total_size(4) +
1798                 /* IFLA_IPTUN_FLAGS */
1799                 nla_total_size(4) +
1800                 /* IFLA_IPTUN_PROTO */
1801                 nla_total_size(1) +
1802                 0;
1803 }
1804 
1805 static int ip6_tnl_fill_info(struct sk_buff *skb, const struct net_device *dev)
1806 {
1807         struct ip6_tnl *tunnel = netdev_priv(dev);
1808         struct __ip6_tnl_parm *parm = &tunnel->parms;
1809 
1810         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1811             nla_put_in6_addr(skb, IFLA_IPTUN_LOCAL, &parm->laddr) ||
1812             nla_put_in6_addr(skb, IFLA_IPTUN_REMOTE, &parm->raddr) ||
1813             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->hop_limit) ||
1814             nla_put_u8(skb, IFLA_IPTUN_ENCAP_LIMIT, parm->encap_limit) ||
1815             nla_put_be32(skb, IFLA_IPTUN_FLOWINFO, parm->flowinfo) ||
1816             nla_put_u32(skb, IFLA_IPTUN_FLAGS, parm->flags) ||
1817             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->proto))
1818                 goto nla_put_failure;
1819         return 0;
1820 
1821 nla_put_failure:
1822         return -EMSGSIZE;
1823 }
1824 
1825 struct net *ip6_tnl_get_link_net(const struct net_device *dev)
1826 {
1827         struct ip6_tnl *tunnel = netdev_priv(dev);
1828 
1829         return tunnel->net;
1830 }
1831 EXPORT_SYMBOL(ip6_tnl_get_link_net);
1832 
1833 static const struct nla_policy ip6_tnl_policy[IFLA_IPTUN_MAX + 1] = {
1834         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1835         [IFLA_IPTUN_LOCAL]              = { .len = sizeof(struct in6_addr) },
1836         [IFLA_IPTUN_REMOTE]             = { .len = sizeof(struct in6_addr) },
1837         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1838         [IFLA_IPTUN_ENCAP_LIMIT]        = { .type = NLA_U8 },
1839         [IFLA_IPTUN_FLOWINFO]           = { .type = NLA_U32 },
1840         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U32 },
1841         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1842 };
1843 
1844 static struct rtnl_link_ops ip6_link_ops __read_mostly = {
1845         .kind           = "ip6tnl",
1846         .maxtype        = IFLA_IPTUN_MAX,
1847         .policy         = ip6_tnl_policy,
1848         .priv_size      = sizeof(struct ip6_tnl),
1849         .setup          = ip6_tnl_dev_setup,
1850         .validate       = ip6_tnl_validate,
1851         .newlink        = ip6_tnl_newlink,
1852         .changelink     = ip6_tnl_changelink,
1853         .dellink        = ip6_tnl_dellink,
1854         .get_size       = ip6_tnl_get_size,
1855         .fill_info      = ip6_tnl_fill_info,
1856         .get_link_net   = ip6_tnl_get_link_net,
1857 };
1858 
1859 static struct xfrm6_tunnel ip4ip6_handler __read_mostly = {
1860         .handler        = ip4ip6_rcv,
1861         .err_handler    = ip4ip6_err,
1862         .priority       =       1,
1863 };
1864 
1865 static struct xfrm6_tunnel ip6ip6_handler __read_mostly = {
1866         .handler        = ip6ip6_rcv,
1867         .err_handler    = ip6ip6_err,
1868         .priority       =       1,
1869 };
1870 
1871 static void __net_exit ip6_tnl_destroy_tunnels(struct net *net)
1872 {
1873         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1874         struct net_device *dev, *aux;
1875         int h;
1876         struct ip6_tnl *t;
1877         LIST_HEAD(list);
1878 
1879         for_each_netdev_safe(net, dev, aux)
1880                 if (dev->rtnl_link_ops == &ip6_link_ops)
1881                         unregister_netdevice_queue(dev, &list);
1882 
1883         for (h = 0; h < HASH_SIZE; h++) {
1884                 t = rtnl_dereference(ip6n->tnls_r_l[h]);
1885                 while (t) {
1886                         /* If dev is in the same netns, it has already
1887                          * been added to the list by the previous loop.
1888                          */
1889                         if (!net_eq(dev_net(t->dev), net))
1890                                 unregister_netdevice_queue(t->dev, &list);
1891                         t = rtnl_dereference(t->next);
1892                 }
1893         }
1894 
1895         unregister_netdevice_many(&list);
1896 }
1897 
1898 static int __net_init ip6_tnl_init_net(struct net *net)
1899 {
1900         struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
1901         struct ip6_tnl *t = NULL;
1902         int err;
1903 
1904         ip6n->tnls[0] = ip6n->tnls_wc;
1905         ip6n->tnls[1] = ip6n->tnls_r_l;
1906 
1907         err = -ENOMEM;
1908         ip6n->fb_tnl_dev = alloc_netdev(sizeof(struct ip6_tnl), "ip6tnl0",
1909                                         NET_NAME_UNKNOWN, ip6_tnl_dev_setup);
1910 
1911         if (!ip6n->fb_tnl_dev)
1912                 goto err_alloc_dev;
1913         dev_net_set(ip6n->fb_tnl_dev, net);
1914         ip6n->fb_tnl_dev->rtnl_link_ops = &ip6_link_ops;
1915         /* FB netdevice is special: we have one, and only one per netns.
1916          * Allowing to move it to another netns is clearly unsafe.
1917          */
1918         ip6n->fb_tnl_dev->features |= NETIF_F_NETNS_LOCAL;
1919 
1920         err = ip6_fb_tnl_dev_init(ip6n->fb_tnl_dev);
1921         if (err < 0)
1922                 goto err_register;
1923 
1924         err = register_netdev(ip6n->fb_tnl_dev);
1925         if (err < 0)
1926                 goto err_register;
1927 
1928         t = netdev_priv(ip6n->fb_tnl_dev);
1929 
1930         strcpy(t->parms.name, ip6n->fb_tnl_dev->name);
1931         return 0;
1932 
1933 err_register:
1934         ip6_dev_free(ip6n->fb_tnl_dev);
1935 err_alloc_dev:
1936         return err;
1937 }
1938 
1939 static void __net_exit ip6_tnl_exit_net(struct net *net)
1940 {
1941         rtnl_lock();
1942         ip6_tnl_destroy_tunnels(net);
1943         rtnl_unlock();
1944 }
1945 
1946 static struct pernet_operations ip6_tnl_net_ops = {
1947         .init = ip6_tnl_init_net,
1948         .exit = ip6_tnl_exit_net,
1949         .id   = &ip6_tnl_net_id,
1950         .size = sizeof(struct ip6_tnl_net),
1951 };
1952 
1953 /**
1954  * ip6_tunnel_init - register protocol and reserve needed resources
1955  *
1956  * Return: 0 on success
1957  **/
1958 
1959 static int __init ip6_tunnel_init(void)
1960 {
1961         int  err;
1962 
1963         err = register_pernet_device(&ip6_tnl_net_ops);
1964         if (err < 0)
1965                 goto out_pernet;
1966 
1967         err = xfrm6_tunnel_register(&ip4ip6_handler, AF_INET);
1968         if (err < 0) {
1969                 pr_err("%s: can't register ip4ip6\n", __func__);
1970                 goto out_ip4ip6;
1971         }
1972 
1973         err = xfrm6_tunnel_register(&ip6ip6_handler, AF_INET6);
1974         if (err < 0) {
1975                 pr_err("%s: can't register ip6ip6\n", __func__);
1976                 goto out_ip6ip6;
1977         }
1978         err = rtnl_link_register(&ip6_link_ops);
1979         if (err < 0)
1980                 goto rtnl_link_failed;
1981 
1982         return 0;
1983 
1984 rtnl_link_failed:
1985         xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6);
1986 out_ip6ip6:
1987         xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET);
1988 out_ip4ip6:
1989         unregister_pernet_device(&ip6_tnl_net_ops);
1990 out_pernet:
1991         return err;
1992 }
1993 
1994 /**
1995  * ip6_tunnel_cleanup - free resources and unregister protocol
1996  **/
1997 
1998 static void __exit ip6_tunnel_cleanup(void)
1999 {
2000         rtnl_link_unregister(&ip6_link_ops);
2001         if (xfrm6_tunnel_deregister(&ip4ip6_handler, AF_INET))
2002                 pr_info("%s: can't deregister ip4ip6\n", __func__);
2003 
2004         if (xfrm6_tunnel_deregister(&ip6ip6_handler, AF_INET6))
2005                 pr_info("%s: can't deregister ip6ip6\n", __func__);
2006 
2007         unregister_pernet_device(&ip6_tnl_net_ops);
2008 }
2009 
2010 module_init(ip6_tunnel_init);
2011 module_exit(ip6_tunnel_cleanup);
2012 

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