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

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  1 // SPDX-License-Identifier: GPL-2.0-or-later
  2 /*
  3  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
  4  *      Linux INET6 implementation
  5  *
  6  *      Authors:
  7  *      Pedro Roque             <roque@di.fc.ul.pt>
  8  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  9  *
 10  *      Changes:
 11  * Roger Venning <r.venning@telstra.com>:       6to4 support
 12  * Nate Thompson <nate@thebog.net>:             6to4 support
 13  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
 14  */
 15 
 16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 17 
 18 #include <linux/module.h>
 19 #include <linux/capability.h>
 20 #include <linux/errno.h>
 21 #include <linux/types.h>
 22 #include <linux/socket.h>
 23 #include <linux/sockios.h>
 24 #include <linux/net.h>
 25 #include <linux/in6.h>
 26 #include <linux/netdevice.h>
 27 #include <linux/if_arp.h>
 28 #include <linux/icmp.h>
 29 #include <linux/slab.h>
 30 #include <linux/uaccess.h>
 31 #include <linux/init.h>
 32 #include <linux/netfilter_ipv4.h>
 33 #include <linux/if_ether.h>
 34 
 35 #include <net/sock.h>
 36 #include <net/snmp.h>
 37 
 38 #include <net/ipv6.h>
 39 #include <net/protocol.h>
 40 #include <net/transp_v6.h>
 41 #include <net/ip6_fib.h>
 42 #include <net/ip6_route.h>
 43 #include <net/ndisc.h>
 44 #include <net/addrconf.h>
 45 #include <net/ip.h>
 46 #include <net/udp.h>
 47 #include <net/icmp.h>
 48 #include <net/ip_tunnels.h>
 49 #include <net/inet_ecn.h>
 50 #include <net/xfrm.h>
 51 #include <net/dsfield.h>
 52 #include <net/net_namespace.h>
 53 #include <net/netns/generic.h>
 54 
 55 /*
 56    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
 57 
 58    For comments look at net/ipv4/ip_gre.c --ANK
 59  */
 60 
 61 #define IP6_SIT_HASH_SIZE  16
 62 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 63 
 64 static bool log_ecn_error = true;
 65 module_param(log_ecn_error, bool, 0644);
 66 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
 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 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
 72                       __be32 *v4dst);
 73 static struct rtnl_link_ops sit_link_ops __read_mostly;
 74 
 75 static unsigned int sit_net_id __read_mostly;
 76 struct sit_net {
 77         struct ip_tunnel __rcu *tunnels_r_l[IP6_SIT_HASH_SIZE];
 78         struct ip_tunnel __rcu *tunnels_r[IP6_SIT_HASH_SIZE];
 79         struct ip_tunnel __rcu *tunnels_l[IP6_SIT_HASH_SIZE];
 80         struct ip_tunnel __rcu *tunnels_wc[1];
 81         struct ip_tunnel __rcu **tunnels[4];
 82 
 83         struct net_device *fb_tunnel_dev;
 84 };
 85 
 86 static inline struct sit_net *dev_to_sit_net(struct net_device *dev)
 87 {
 88         struct ip_tunnel *t = netdev_priv(dev);
 89 
 90         return net_generic(t->net, sit_net_id);
 91 }
 92 
 93 /*
 94  * Must be invoked with rcu_read_lock
 95  */
 96 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
 97                                              struct net_device *dev,
 98                                              __be32 remote, __be32 local,
 99                                              int sifindex)
100 {
101         unsigned int h0 = HASH(remote);
102         unsigned int h1 = HASH(local);
103         struct ip_tunnel *t;
104         struct sit_net *sitn = net_generic(net, sit_net_id);
105         int ifindex = dev ? dev->ifindex : 0;
106 
107         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
108                 if (local == t->parms.iph.saddr &&
109                     remote == t->parms.iph.daddr &&
110                     (!dev || !t->parms.link || ifindex == t->parms.link ||
111                      sifindex == t->parms.link) &&
112                     (t->dev->flags & IFF_UP))
113                         return t;
114         }
115         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
116                 if (remote == t->parms.iph.daddr &&
117                     (!dev || !t->parms.link || ifindex == t->parms.link ||
118                      sifindex == t->parms.link) &&
119                     (t->dev->flags & IFF_UP))
120                         return t;
121         }
122         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
123                 if (local == t->parms.iph.saddr &&
124                     (!dev || !t->parms.link || ifindex == t->parms.link ||
125                      sifindex == t->parms.link) &&
126                     (t->dev->flags & IFF_UP))
127                         return t;
128         }
129         t = rcu_dereference(sitn->tunnels_wc[0]);
130         if (t && (t->dev->flags & IFF_UP))
131                 return t;
132         return NULL;
133 }
134 
135 static struct ip_tunnel __rcu **
136 __ipip6_bucket(struct sit_net *sitn, struct ip_tunnel_parm_kern *parms)
137 {
138         __be32 remote = parms->iph.daddr;
139         __be32 local = parms->iph.saddr;
140         unsigned int h = 0;
141         int prio = 0;
142 
143         if (remote) {
144                 prio |= 2;
145                 h ^= HASH(remote);
146         }
147         if (local) {
148                 prio |= 1;
149                 h ^= HASH(local);
150         }
151         return &sitn->tunnels[prio][h];
152 }
153 
154 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
155                 struct ip_tunnel *t)
156 {
157         return __ipip6_bucket(sitn, &t->parms);
158 }
159 
160 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
161 {
162         struct ip_tunnel __rcu **tp;
163         struct ip_tunnel *iter;
164 
165         for (tp = ipip6_bucket(sitn, t);
166              (iter = rtnl_dereference(*tp)) != NULL;
167              tp = &iter->next) {
168                 if (t == iter) {
169                         rcu_assign_pointer(*tp, t->next);
170                         break;
171                 }
172         }
173 }
174 
175 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
176 {
177         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
178 
179         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
180         rcu_assign_pointer(*tp, t);
181 }
182 
183 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
184 {
185 #ifdef CONFIG_IPV6_SIT_6RD
186         struct ip_tunnel *t = netdev_priv(dev);
187 
188         if (dev == sitn->fb_tunnel_dev || !sitn->fb_tunnel_dev) {
189                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
190                 t->ip6rd.relay_prefix = 0;
191                 t->ip6rd.prefixlen = 16;
192                 t->ip6rd.relay_prefixlen = 0;
193         } else {
194                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
195                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
196         }
197 #endif
198 }
199 
200 static int ipip6_tunnel_create(struct net_device *dev)
201 {
202         struct ip_tunnel *t = netdev_priv(dev);
203         struct net *net = dev_net(dev);
204         struct sit_net *sitn = net_generic(net, sit_net_id);
205         int err;
206 
207         __dev_addr_set(dev, &t->parms.iph.saddr, 4);
208         memcpy(dev->broadcast, &t->parms.iph.daddr, 4);
209 
210         if (test_bit(IP_TUNNEL_SIT_ISATAP_BIT, t->parms.i_flags))
211                 dev->priv_flags |= IFF_ISATAP;
212 
213         dev->rtnl_link_ops = &sit_link_ops;
214 
215         err = register_netdevice(dev);
216         if (err < 0)
217                 goto out;
218 
219         ipip6_tunnel_clone_6rd(dev, sitn);
220 
221         ipip6_tunnel_link(sitn, t);
222         return 0;
223 
224 out:
225         return err;
226 }
227 
228 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
229                                              struct ip_tunnel_parm_kern *parms,
230                                              int create)
231 {
232         __be32 remote = parms->iph.daddr;
233         __be32 local = parms->iph.saddr;
234         struct ip_tunnel *t, *nt;
235         struct ip_tunnel __rcu **tp;
236         struct net_device *dev;
237         char name[IFNAMSIZ];
238         struct sit_net *sitn = net_generic(net, sit_net_id);
239 
240         for (tp = __ipip6_bucket(sitn, parms);
241             (t = rtnl_dereference(*tp)) != NULL;
242              tp = &t->next) {
243                 if (local == t->parms.iph.saddr &&
244                     remote == t->parms.iph.daddr &&
245                     parms->link == t->parms.link) {
246                         if (create)
247                                 return NULL;
248                         else
249                                 return t;
250                 }
251         }
252         if (!create)
253                 goto failed;
254 
255         if (parms->name[0]) {
256                 if (!dev_valid_name(parms->name))
257                         goto failed;
258                 strscpy(name, parms->name, IFNAMSIZ);
259         } else {
260                 strcpy(name, "sit%d");
261         }
262         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
263                            ipip6_tunnel_setup);
264         if (!dev)
265                 return NULL;
266 
267         dev_net_set(dev, net);
268 
269         nt = netdev_priv(dev);
270 
271         nt->parms = *parms;
272         if (ipip6_tunnel_create(dev) < 0)
273                 goto failed_free;
274 
275         if (!parms->name[0])
276                 strcpy(parms->name, dev->name);
277 
278         return nt;
279 
280 failed_free:
281         free_netdev(dev);
282 failed:
283         return NULL;
284 }
285 
286 #define for_each_prl_rcu(start)                 \
287         for (prl = rcu_dereference(start);      \
288              prl;                               \
289              prl = rcu_dereference(prl->next))
290 
291 static struct ip_tunnel_prl_entry *
292 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
293 {
294         struct ip_tunnel_prl_entry *prl;
295 
296         for_each_prl_rcu(t->prl)
297                 if (prl->addr == addr)
298                         break;
299         return prl;
300 
301 }
302 
303 static int ipip6_tunnel_get_prl(struct net_device *dev, struct ip_tunnel_prl __user *a)
304 {
305         struct ip_tunnel *t = netdev_priv(dev);
306         struct ip_tunnel_prl kprl, *kp;
307         struct ip_tunnel_prl_entry *prl;
308         unsigned int cmax, c = 0, ca, len;
309         int ret = 0;
310 
311         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
312                 return -EINVAL;
313 
314         if (copy_from_user(&kprl, a, sizeof(kprl)))
315                 return -EFAULT;
316         cmax = kprl.datalen / sizeof(kprl);
317         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
318                 cmax = 1;
319 
320         /* For simple GET or for root users,
321          * we try harder to allocate.
322          */
323         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
324                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL_ACCOUNT | __GFP_NOWARN) :
325                 NULL;
326 
327         ca = min(t->prl_count, cmax);
328 
329         if (!kp) {
330                 /* We don't try hard to allocate much memory for
331                  * non-root users.
332                  * For root users, retry allocating enough memory for
333                  * the answer.
334                  */
335                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC | __GFP_ACCOUNT |
336                                               __GFP_NOWARN);
337                 if (!kp) {
338                         ret = -ENOMEM;
339                         goto out;
340                 }
341         }
342 
343         rcu_read_lock();
344         for_each_prl_rcu(t->prl) {
345                 if (c >= cmax)
346                         break;
347                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
348                         continue;
349                 kp[c].addr = prl->addr;
350                 kp[c].flags = prl->flags;
351                 c++;
352                 if (kprl.addr != htonl(INADDR_ANY))
353                         break;
354         }
355 
356         rcu_read_unlock();
357 
358         len = sizeof(*kp) * c;
359         ret = 0;
360         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
361                 ret = -EFAULT;
362 
363         kfree(kp);
364 out:
365         return ret;
366 }
367 
368 static int
369 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
370 {
371         struct ip_tunnel_prl_entry *p;
372         int err = 0;
373 
374         if (a->addr == htonl(INADDR_ANY))
375                 return -EINVAL;
376 
377         ASSERT_RTNL();
378 
379         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
380                 if (p->addr == a->addr) {
381                         if (chg) {
382                                 p->flags = a->flags;
383                                 goto out;
384                         }
385                         err = -EEXIST;
386                         goto out;
387                 }
388         }
389 
390         if (chg) {
391                 err = -ENXIO;
392                 goto out;
393         }
394 
395         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
396         if (!p) {
397                 err = -ENOBUFS;
398                 goto out;
399         }
400 
401         p->next = t->prl;
402         p->addr = a->addr;
403         p->flags = a->flags;
404         t->prl_count++;
405         rcu_assign_pointer(t->prl, p);
406 out:
407         return err;
408 }
409 
410 static void prl_list_destroy_rcu(struct rcu_head *head)
411 {
412         struct ip_tunnel_prl_entry *p, *n;
413 
414         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
415         do {
416                 n = rcu_dereference_protected(p->next, 1);
417                 kfree(p);
418                 p = n;
419         } while (p);
420 }
421 
422 static int
423 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
424 {
425         struct ip_tunnel_prl_entry *x;
426         struct ip_tunnel_prl_entry __rcu **p;
427         int err = 0;
428 
429         ASSERT_RTNL();
430 
431         if (a && a->addr != htonl(INADDR_ANY)) {
432                 for (p = &t->prl;
433                      (x = rtnl_dereference(*p)) != NULL;
434                      p = &x->next) {
435                         if (x->addr == a->addr) {
436                                 *p = x->next;
437                                 kfree_rcu(x, rcu_head);
438                                 t->prl_count--;
439                                 goto out;
440                         }
441                 }
442                 err = -ENXIO;
443         } else {
444                 x = rtnl_dereference(t->prl);
445                 if (x) {
446                         t->prl_count = 0;
447                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
448                         t->prl = NULL;
449                 }
450         }
451 out:
452         return err;
453 }
454 
455 static int ipip6_tunnel_prl_ctl(struct net_device *dev,
456                                 struct ip_tunnel_prl __user *data, int cmd)
457 {
458         struct ip_tunnel *t = netdev_priv(dev);
459         struct ip_tunnel_prl prl;
460         int err;
461 
462         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
463                 return -EPERM;
464         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
465                 return -EINVAL;
466 
467         if (copy_from_user(&prl, data, sizeof(prl)))
468                 return -EFAULT;
469 
470         switch (cmd) {
471         case SIOCDELPRL:
472                 err = ipip6_tunnel_del_prl(t, &prl);
473                 break;
474         case SIOCADDPRL:
475         case SIOCCHGPRL:
476                 err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
477                 break;
478         }
479         dst_cache_reset(&t->dst_cache);
480         netdev_state_change(dev);
481         return err;
482 }
483 
484 static int
485 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
486 {
487         struct ip_tunnel_prl_entry *p;
488         int ok = 1;
489 
490         rcu_read_lock();
491         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
492         if (p) {
493                 if (p->flags & PRL_DEFAULT)
494                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
495                 else
496                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
497         } else {
498                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
499 
500                 if (ipv6_addr_is_isatap(addr6) &&
501                     (addr6->s6_addr32[3] == iph->saddr) &&
502                     ipv6_chk_prefix(addr6, t->dev))
503                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
504                 else
505                         ok = 0;
506         }
507         rcu_read_unlock();
508         return ok;
509 }
510 
511 static void ipip6_tunnel_uninit(struct net_device *dev)
512 {
513         struct ip_tunnel *tunnel = netdev_priv(dev);
514         struct sit_net *sitn = net_generic(tunnel->net, sit_net_id);
515 
516         if (dev == sitn->fb_tunnel_dev) {
517                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
518         } else {
519                 ipip6_tunnel_unlink(sitn, tunnel);
520                 ipip6_tunnel_del_prl(tunnel, NULL);
521         }
522         dst_cache_reset(&tunnel->dst_cache);
523         netdev_put(dev, &tunnel->dev_tracker);
524 }
525 
526 static int ipip6_err(struct sk_buff *skb, u32 info)
527 {
528         const struct iphdr *iph = (const struct iphdr *)skb->data;
529         const int type = icmp_hdr(skb)->type;
530         const int code = icmp_hdr(skb)->code;
531         unsigned int data_len = 0;
532         struct ip_tunnel *t;
533         int sifindex;
534         int err;
535 
536         switch (type) {
537         default:
538         case ICMP_PARAMETERPROB:
539                 return 0;
540 
541         case ICMP_DEST_UNREACH:
542                 switch (code) {
543                 case ICMP_SR_FAILED:
544                         /* Impossible event. */
545                         return 0;
546                 default:
547                         /* All others are translated to HOST_UNREACH.
548                            rfc2003 contains "deep thoughts" about NET_UNREACH,
549                            I believe they are just ether pollution. --ANK
550                          */
551                         break;
552                 }
553                 break;
554         case ICMP_TIME_EXCEEDED:
555                 if (code != ICMP_EXC_TTL)
556                         return 0;
557                 data_len = icmp_hdr(skb)->un.reserved[1] * 4; /* RFC 4884 4.1 */
558                 break;
559         case ICMP_REDIRECT:
560                 break;
561         }
562 
563         err = -ENOENT;
564 
565         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
566         t = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
567                                 iph->daddr, iph->saddr, sifindex);
568         if (!t)
569                 goto out;
570 
571         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
572                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
573                                  t->parms.link, iph->protocol);
574                 err = 0;
575                 goto out;
576         }
577         if (type == ICMP_REDIRECT) {
578                 ipv4_redirect(skb, dev_net(skb->dev), t->parms.link,
579                               iph->protocol);
580                 err = 0;
581                 goto out;
582         }
583 
584         err = 0;
585         if (__in6_dev_get(skb->dev) &&
586             !ip6_err_gen_icmpv6_unreach(skb, iph->ihl * 4, type, data_len))
587                 goto out;
588 
589         if (t->parms.iph.daddr == 0)
590                 goto out;
591 
592         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
593                 goto out;
594 
595         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
596                 t->err_count++;
597         else
598                 t->err_count = 1;
599         t->err_time = jiffies;
600 out:
601         return err;
602 }
603 
604 static inline bool is_spoofed_6rd(struct ip_tunnel *tunnel, const __be32 v4addr,
605                                   const struct in6_addr *v6addr)
606 {
607         __be32 v4embed = 0;
608         if (check_6rd(tunnel, v6addr, &v4embed) && v4addr != v4embed)
609                 return true;
610         return false;
611 }
612 
613 /* Checks if an address matches an address on the tunnel interface.
614  * Used to detect the NAT of proto 41 packets and let them pass spoofing test.
615  * Long story:
616  * This function is called after we considered the packet as spoofed
617  * in is_spoofed_6rd.
618  * We may have a router that is doing NAT for proto 41 packets
619  * for an internal station. Destination a.a.a.a/PREFIX:bbbb:bbbb
620  * will be translated to n.n.n.n/PREFIX:bbbb:bbbb. And is_spoofed_6rd
621  * function will return true, dropping the packet.
622  * But, we can still check if is spoofed against the IP
623  * addresses associated with the interface.
624  */
625 static bool only_dnatted(const struct ip_tunnel *tunnel,
626         const struct in6_addr *v6dst)
627 {
628         int prefix_len;
629 
630 #ifdef CONFIG_IPV6_SIT_6RD
631         prefix_len = tunnel->ip6rd.prefixlen + 32
632                 - tunnel->ip6rd.relay_prefixlen;
633 #else
634         prefix_len = 48;
635 #endif
636         return ipv6_chk_custom_prefix(v6dst, prefix_len, tunnel->dev);
637 }
638 
639 /* Returns true if a packet is spoofed */
640 static bool packet_is_spoofed(struct sk_buff *skb,
641                               const struct iphdr *iph,
642                               struct ip_tunnel *tunnel)
643 {
644         const struct ipv6hdr *ipv6h;
645 
646         if (tunnel->dev->priv_flags & IFF_ISATAP) {
647                 if (!isatap_chksrc(skb, iph, tunnel))
648                         return true;
649 
650                 return false;
651         }
652 
653         if (tunnel->dev->flags & IFF_POINTOPOINT)
654                 return false;
655 
656         ipv6h = ipv6_hdr(skb);
657 
658         if (unlikely(is_spoofed_6rd(tunnel, iph->saddr, &ipv6h->saddr))) {
659                 net_warn_ratelimited("Src spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
660                                      &iph->saddr, &ipv6h->saddr,
661                                      &iph->daddr, &ipv6h->daddr);
662                 return true;
663         }
664 
665         if (likely(!is_spoofed_6rd(tunnel, iph->daddr, &ipv6h->daddr)))
666                 return false;
667 
668         if (only_dnatted(tunnel, &ipv6h->daddr))
669                 return false;
670 
671         net_warn_ratelimited("Dst spoofed %pI4/%pI6c -> %pI4/%pI6c\n",
672                              &iph->saddr, &ipv6h->saddr,
673                              &iph->daddr, &ipv6h->daddr);
674         return true;
675 }
676 
677 static int ipip6_rcv(struct sk_buff *skb)
678 {
679         const struct iphdr *iph = ip_hdr(skb);
680         struct ip_tunnel *tunnel;
681         int sifindex;
682         int err;
683 
684         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
685         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
686                                      iph->saddr, iph->daddr, sifindex);
687         if (tunnel) {
688                 if (tunnel->parms.iph.protocol != IPPROTO_IPV6 &&
689                     tunnel->parms.iph.protocol != 0)
690                         goto out;
691 
692                 skb->mac_header = skb->network_header;
693                 skb_reset_network_header(skb);
694                 IPCB(skb)->flags = 0;
695                 skb->dev = tunnel->dev;
696 
697                 if (packet_is_spoofed(skb, iph, tunnel)) {
698                         DEV_STATS_INC(tunnel->dev, rx_errors);
699                         goto out;
700                 }
701 
702                 if (iptunnel_pull_header(skb, 0, htons(ETH_P_IPV6),
703                     !net_eq(tunnel->net, dev_net(tunnel->dev))))
704                         goto out;
705 
706                 /* skb can be uncloned in iptunnel_pull_header, so
707                  * old iph is no longer valid
708                  */
709                 iph = (const struct iphdr *)skb_mac_header(skb);
710                 skb_reset_mac_header(skb);
711 
712                 err = IP_ECN_decapsulate(iph, skb);
713                 if (unlikely(err)) {
714                         if (log_ecn_error)
715                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
716                                                      &iph->saddr, iph->tos);
717                         if (err > 1) {
718                                 DEV_STATS_INC(tunnel->dev, rx_frame_errors);
719                                 DEV_STATS_INC(tunnel->dev, rx_errors);
720                                 goto out;
721                         }
722                 }
723 
724                 dev_sw_netstats_rx_add(tunnel->dev, skb->len);
725 
726                 netif_rx(skb);
727 
728                 return 0;
729         }
730 
731         /* no tunnel matched,  let upstream know, ipsec may handle it */
732         return 1;
733 out:
734         kfree_skb(skb);
735         return 0;
736 }
737 
738 static const struct tnl_ptk_info ipip_tpi = {
739         /* no tunnel info required for ipip. */
740         .proto = htons(ETH_P_IP),
741 };
742 
743 #if IS_ENABLED(CONFIG_MPLS)
744 static const struct tnl_ptk_info mplsip_tpi = {
745         /* no tunnel info required for mplsip. */
746         .proto = htons(ETH_P_MPLS_UC),
747 };
748 #endif
749 
750 static int sit_tunnel_rcv(struct sk_buff *skb, u8 ipproto)
751 {
752         const struct iphdr *iph;
753         struct ip_tunnel *tunnel;
754         int sifindex;
755 
756         sifindex = netif_is_l3_master(skb->dev) ? IPCB(skb)->iif : 0;
757 
758         iph = ip_hdr(skb);
759         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
760                                      iph->saddr, iph->daddr, sifindex);
761         if (tunnel) {
762                 const struct tnl_ptk_info *tpi;
763 
764                 if (tunnel->parms.iph.protocol != ipproto &&
765                     tunnel->parms.iph.protocol != 0)
766                         goto drop;
767 
768                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
769                         goto drop;
770 #if IS_ENABLED(CONFIG_MPLS)
771                 if (ipproto == IPPROTO_MPLS)
772                         tpi = &mplsip_tpi;
773                 else
774 #endif
775                         tpi = &ipip_tpi;
776                 if (iptunnel_pull_header(skb, 0, tpi->proto, false))
777                         goto drop;
778                 skb_reset_mac_header(skb);
779 
780                 return ip_tunnel_rcv(tunnel, skb, tpi, NULL, log_ecn_error);
781         }
782 
783         return 1;
784 
785 drop:
786         kfree_skb(skb);
787         return 0;
788 }
789 
790 static int ipip_rcv(struct sk_buff *skb)
791 {
792         return sit_tunnel_rcv(skb, IPPROTO_IPIP);
793 }
794 
795 #if IS_ENABLED(CONFIG_MPLS)
796 static int mplsip_rcv(struct sk_buff *skb)
797 {
798         return sit_tunnel_rcv(skb, IPPROTO_MPLS);
799 }
800 #endif
801 
802 /*
803  * If the IPv6 address comes from 6rd / 6to4 (RFC 3056) addr space this function
804  * stores the embedded IPv4 address in v4dst and returns true.
805  */
806 static bool check_6rd(struct ip_tunnel *tunnel, const struct in6_addr *v6dst,
807                       __be32 *v4dst)
808 {
809 #ifdef CONFIG_IPV6_SIT_6RD
810         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
811                               tunnel->ip6rd.prefixlen)) {
812                 unsigned int pbw0, pbi0;
813                 int pbi1;
814                 u32 d;
815 
816                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
817                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
818 
819                 d = tunnel->ip6rd.relay_prefixlen < 32 ?
820                         (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
821                     tunnel->ip6rd.relay_prefixlen : 0;
822 
823                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
824                 if (pbi1 > 0)
825                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
826                              (32 - pbi1);
827 
828                 *v4dst = tunnel->ip6rd.relay_prefix | htonl(d);
829                 return true;
830         }
831 #else
832         if (v6dst->s6_addr16[0] == htons(0x2002)) {
833                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
834                 memcpy(v4dst, &v6dst->s6_addr16[1], 4);
835                 return true;
836         }
837 #endif
838         return false;
839 }
840 
841 static inline __be32 try_6rd(struct ip_tunnel *tunnel,
842                              const struct in6_addr *v6dst)
843 {
844         __be32 dst = 0;
845         check_6rd(tunnel, v6dst, &dst);
846         return dst;
847 }
848 
849 /*
850  *      This function assumes it is being called from dev_queue_xmit()
851  *      and that skb is filled properly by that function.
852  */
853 
854 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
855                                      struct net_device *dev)
856 {
857         struct ip_tunnel *tunnel = netdev_priv(dev);
858         const struct iphdr  *tiph = &tunnel->parms.iph;
859         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
860         u8     tos = tunnel->parms.iph.tos;
861         __be16 df = tiph->frag_off;
862         struct rtable *rt;              /* Route to the other host */
863         struct net_device *tdev;        /* Device to other host */
864         unsigned int max_headroom;      /* The extra header space needed */
865         __be32 dst = tiph->daddr;
866         struct flowi4 fl4;
867         int    mtu;
868         const struct in6_addr *addr6;
869         int addr_type;
870         u8 ttl;
871         u8 protocol = IPPROTO_IPV6;
872         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
873 
874         if (tos == 1)
875                 tos = ipv6_get_dsfield(iph6);
876 
877         /* ISATAP (RFC4214) - must come before 6to4 */
878         if (dev->priv_flags & IFF_ISATAP) {
879                 struct neighbour *neigh = NULL;
880                 bool do_tx_error = false;
881 
882                 if (skb_dst(skb))
883                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
884 
885                 if (!neigh) {
886                         net_dbg_ratelimited("nexthop == NULL\n");
887                         goto tx_error;
888                 }
889 
890                 addr6 = (const struct in6_addr *)&neigh->primary_key;
891                 addr_type = ipv6_addr_type(addr6);
892 
893                 if ((addr_type & IPV6_ADDR_UNICAST) &&
894                      ipv6_addr_is_isatap(addr6))
895                         dst = addr6->s6_addr32[3];
896                 else
897                         do_tx_error = true;
898 
899                 neigh_release(neigh);
900                 if (do_tx_error)
901                         goto tx_error;
902         }
903 
904         if (!dst)
905                 dst = try_6rd(tunnel, &iph6->daddr);
906 
907         if (!dst) {
908                 struct neighbour *neigh = NULL;
909                 bool do_tx_error = false;
910 
911                 if (skb_dst(skb))
912                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
913 
914                 if (!neigh) {
915                         net_dbg_ratelimited("nexthop == NULL\n");
916                         goto tx_error;
917                 }
918 
919                 addr6 = (const struct in6_addr *)&neigh->primary_key;
920                 addr_type = ipv6_addr_type(addr6);
921 
922                 if (addr_type == IPV6_ADDR_ANY) {
923                         addr6 = &ipv6_hdr(skb)->daddr;
924                         addr_type = ipv6_addr_type(addr6);
925                 }
926 
927                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
928                         dst = addr6->s6_addr32[3];
929                 else
930                         do_tx_error = true;
931 
932                 neigh_release(neigh);
933                 if (do_tx_error)
934                         goto tx_error;
935         }
936 
937         flowi4_init_output(&fl4, tunnel->parms.link, tunnel->fwmark,
938                            RT_TOS(tos), RT_SCOPE_UNIVERSE, IPPROTO_IPV6,
939                            0, dst, tiph->saddr, 0, 0,
940                            sock_net_uid(tunnel->net, NULL));
941 
942         rt = dst_cache_get_ip4(&tunnel->dst_cache, &fl4.saddr);
943         if (!rt) {
944                 rt = ip_route_output_flow(tunnel->net, &fl4, NULL);
945                 if (IS_ERR(rt)) {
946                         DEV_STATS_INC(dev, tx_carrier_errors);
947                         goto tx_error_icmp;
948                 }
949                 dst_cache_set_ip4(&tunnel->dst_cache, &rt->dst, fl4.saddr);
950         }
951 
952         if (rt->rt_type != RTN_UNICAST && rt->rt_type != RTN_LOCAL) {
953                 ip_rt_put(rt);
954                 DEV_STATS_INC(dev, tx_carrier_errors);
955                 goto tx_error_icmp;
956         }
957         tdev = rt->dst.dev;
958 
959         if (tdev == dev) {
960                 ip_rt_put(rt);
961                 DEV_STATS_INC(dev, collisions);
962                 goto tx_error;
963         }
964 
965         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4)) {
966                 ip_rt_put(rt);
967                 goto tx_error;
968         }
969 
970         if (df) {
971                 mtu = dst_mtu(&rt->dst) - t_hlen;
972 
973                 if (mtu < IPV4_MIN_MTU) {
974                         DEV_STATS_INC(dev, collisions);
975                         ip_rt_put(rt);
976                         goto tx_error;
977                 }
978 
979                 if (mtu < IPV6_MIN_MTU) {
980                         mtu = IPV6_MIN_MTU;
981                         df = 0;
982                 }
983 
984                 if (tunnel->parms.iph.daddr)
985                         skb_dst_update_pmtu_no_confirm(skb, mtu);
986 
987                 if (skb->len > mtu && !skb_is_gso(skb)) {
988                         icmpv6_ndo_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
989                         ip_rt_put(rt);
990                         goto tx_error;
991                 }
992         }
993 
994         if (tunnel->err_count > 0) {
995                 if (time_before(jiffies,
996                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
997                         tunnel->err_count--;
998                         dst_link_failure(skb);
999                 } else
1000                         tunnel->err_count = 0;
1001         }
1002 
1003         /*
1004          * Okay, now see if we can stuff it in the buffer as-is.
1005          */
1006         max_headroom = LL_RESERVED_SPACE(tdev) + t_hlen;
1007 
1008         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
1009             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
1010                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
1011                 if (!new_skb) {
1012                         ip_rt_put(rt);
1013                         DEV_STATS_INC(dev, tx_dropped);
1014                         kfree_skb(skb);
1015                         return NETDEV_TX_OK;
1016                 }
1017                 if (skb->sk)
1018                         skb_set_owner_w(new_skb, skb->sk);
1019                 dev_kfree_skb(skb);
1020                 skb = new_skb;
1021                 iph6 = ipv6_hdr(skb);
1022         }
1023         ttl = tiph->ttl;
1024         if (ttl == 0)
1025                 ttl = iph6->hop_limit;
1026         tos = INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
1027 
1028         if (ip_tunnel_encap(skb, &tunnel->encap, &protocol, &fl4) < 0) {
1029                 ip_rt_put(rt);
1030                 goto tx_error;
1031         }
1032 
1033         skb_set_inner_ipproto(skb, IPPROTO_IPV6);
1034 
1035         iptunnel_xmit(NULL, rt, skb, fl4.saddr, fl4.daddr, protocol, tos, ttl,
1036                       df, !net_eq(tunnel->net, dev_net(dev)));
1037         return NETDEV_TX_OK;
1038 
1039 tx_error_icmp:
1040         dst_link_failure(skb);
1041 tx_error:
1042         kfree_skb(skb);
1043         DEV_STATS_INC(dev, tx_errors);
1044         return NETDEV_TX_OK;
1045 }
1046 
1047 static netdev_tx_t sit_tunnel_xmit__(struct sk_buff *skb,
1048                                      struct net_device *dev, u8 ipproto)
1049 {
1050         struct ip_tunnel *tunnel = netdev_priv(dev);
1051         const struct iphdr  *tiph = &tunnel->parms.iph;
1052 
1053         if (iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4))
1054                 goto tx_error;
1055 
1056         skb_set_inner_ipproto(skb, ipproto);
1057 
1058         ip_tunnel_xmit(skb, dev, tiph, ipproto);
1059         return NETDEV_TX_OK;
1060 tx_error:
1061         kfree_skb(skb);
1062         DEV_STATS_INC(dev, tx_errors);
1063         return NETDEV_TX_OK;
1064 }
1065 
1066 static netdev_tx_t sit_tunnel_xmit(struct sk_buff *skb,
1067                                    struct net_device *dev)
1068 {
1069         if (!pskb_inet_may_pull(skb))
1070                 goto tx_err;
1071 
1072         switch (skb->protocol) {
1073         case htons(ETH_P_IP):
1074                 sit_tunnel_xmit__(skb, dev, IPPROTO_IPIP);
1075                 break;
1076         case htons(ETH_P_IPV6):
1077                 ipip6_tunnel_xmit(skb, dev);
1078                 break;
1079 #if IS_ENABLED(CONFIG_MPLS)
1080         case htons(ETH_P_MPLS_UC):
1081                 sit_tunnel_xmit__(skb, dev, IPPROTO_MPLS);
1082                 break;
1083 #endif
1084         default:
1085                 goto tx_err;
1086         }
1087 
1088         return NETDEV_TX_OK;
1089 
1090 tx_err:
1091         DEV_STATS_INC(dev, tx_errors);
1092         kfree_skb(skb);
1093         return NETDEV_TX_OK;
1094 
1095 }
1096 
1097 static void ipip6_tunnel_bind_dev(struct net_device *dev)
1098 {
1099         struct ip_tunnel *tunnel = netdev_priv(dev);
1100         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1101         struct net_device *tdev = NULL;
1102         int hlen = LL_MAX_HEADER;
1103         const struct iphdr *iph;
1104         struct flowi4 fl4;
1105 
1106         iph = &tunnel->parms.iph;
1107 
1108         if (iph->daddr) {
1109                 struct rtable *rt = ip_route_output_ports(tunnel->net, &fl4,
1110                                                           NULL,
1111                                                           iph->daddr, iph->saddr,
1112                                                           0, 0,
1113                                                           IPPROTO_IPV6,
1114                                                           RT_TOS(iph->tos),
1115                                                           tunnel->parms.link);
1116 
1117                 if (!IS_ERR(rt)) {
1118                         tdev = rt->dst.dev;
1119                         ip_rt_put(rt);
1120                 }
1121                 dev->flags |= IFF_POINTOPOINT;
1122         }
1123 
1124         if (!tdev && tunnel->parms.link)
1125                 tdev = __dev_get_by_index(tunnel->net, tunnel->parms.link);
1126 
1127         if (tdev && !netif_is_l3_master(tdev)) {
1128                 int mtu;
1129 
1130                 mtu = tdev->mtu - t_hlen;
1131                 if (mtu < IPV6_MIN_MTU)
1132                         mtu = IPV6_MIN_MTU;
1133                 WRITE_ONCE(dev->mtu, mtu);
1134                 hlen = tdev->hard_header_len + tdev->needed_headroom;
1135         }
1136         dev->needed_headroom = t_hlen + hlen;
1137 }
1138 
1139 static void ipip6_tunnel_update(struct ip_tunnel *t,
1140                                 struct ip_tunnel_parm_kern *p,
1141                                 __u32 fwmark)
1142 {
1143         struct net *net = t->net;
1144         struct sit_net *sitn = net_generic(net, sit_net_id);
1145 
1146         ipip6_tunnel_unlink(sitn, t);
1147         synchronize_net();
1148         t->parms.iph.saddr = p->iph.saddr;
1149         t->parms.iph.daddr = p->iph.daddr;
1150         __dev_addr_set(t->dev, &p->iph.saddr, 4);
1151         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
1152         ipip6_tunnel_link(sitn, t);
1153         t->parms.iph.ttl = p->iph.ttl;
1154         t->parms.iph.tos = p->iph.tos;
1155         t->parms.iph.frag_off = p->iph.frag_off;
1156         if (t->parms.link != p->link || t->fwmark != fwmark) {
1157                 t->parms.link = p->link;
1158                 t->fwmark = fwmark;
1159                 ipip6_tunnel_bind_dev(t->dev);
1160         }
1161         dst_cache_reset(&t->dst_cache);
1162         netdev_state_change(t->dev);
1163 }
1164 
1165 #ifdef CONFIG_IPV6_SIT_6RD
1166 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
1167                                    struct ip_tunnel_6rd *ip6rd)
1168 {
1169         struct in6_addr prefix;
1170         __be32 relay_prefix;
1171 
1172         if (ip6rd->relay_prefixlen > 32 ||
1173             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
1174                 return -EINVAL;
1175 
1176         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
1177         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
1178                 return -EINVAL;
1179         if (ip6rd->relay_prefixlen)
1180                 relay_prefix = ip6rd->relay_prefix &
1181                                htonl(0xffffffffUL <<
1182                                      (32 - ip6rd->relay_prefixlen));
1183         else
1184                 relay_prefix = 0;
1185         if (relay_prefix != ip6rd->relay_prefix)
1186                 return -EINVAL;
1187 
1188         t->ip6rd.prefix = prefix;
1189         t->ip6rd.relay_prefix = relay_prefix;
1190         t->ip6rd.prefixlen = ip6rd->prefixlen;
1191         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
1192         dst_cache_reset(&t->dst_cache);
1193         netdev_state_change(t->dev);
1194         return 0;
1195 }
1196 
1197 static int
1198 ipip6_tunnel_get6rd(struct net_device *dev, struct ip_tunnel_parm __user *data)
1199 {
1200         struct ip_tunnel *t = netdev_priv(dev);
1201         struct ip_tunnel_parm_kern p;
1202         struct ip_tunnel_6rd ip6rd;
1203 
1204         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1205                 if (!ip_tunnel_parm_from_user(&p, data))
1206                         return -EFAULT;
1207                 t = ipip6_tunnel_locate(t->net, &p, 0);
1208         }
1209         if (!t)
1210                 t = netdev_priv(dev);
1211 
1212         ip6rd.prefix = t->ip6rd.prefix;
1213         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1214         ip6rd.prefixlen = t->ip6rd.prefixlen;
1215         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1216         if (copy_to_user(data, &ip6rd, sizeof(ip6rd)))
1217                 return -EFAULT;
1218         return 0;
1219 }
1220 
1221 static int
1222 ipip6_tunnel_6rdctl(struct net_device *dev, struct ip_tunnel_6rd __user *data,
1223                     int cmd)
1224 {
1225         struct ip_tunnel *t = netdev_priv(dev);
1226         struct ip_tunnel_6rd ip6rd;
1227         int err;
1228 
1229         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1230                 return -EPERM;
1231         if (copy_from_user(&ip6rd, data, sizeof(ip6rd)))
1232                 return -EFAULT;
1233 
1234         if (cmd != SIOCDEL6RD) {
1235                 err = ipip6_tunnel_update_6rd(t, &ip6rd);
1236                 if (err < 0)
1237                         return err;
1238         } else
1239                 ipip6_tunnel_clone_6rd(dev, dev_to_sit_net(dev));
1240         return 0;
1241 }
1242 
1243 #endif /* CONFIG_IPV6_SIT_6RD */
1244 
1245 static bool ipip6_valid_ip_proto(u8 ipproto)
1246 {
1247         return ipproto == IPPROTO_IPV6 ||
1248                 ipproto == IPPROTO_IPIP ||
1249 #if IS_ENABLED(CONFIG_MPLS)
1250                 ipproto == IPPROTO_MPLS ||
1251 #endif
1252                 ipproto == 0;
1253 }
1254 
1255 static int
1256 __ipip6_tunnel_ioctl_validate(struct net *net, struct ip_tunnel_parm_kern *p)
1257 {
1258         if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1259                 return -EPERM;
1260 
1261         if (!ipip6_valid_ip_proto(p->iph.protocol))
1262                 return -EINVAL;
1263         if (p->iph.version != 4 ||
1264             p->iph.ihl != 5 || (p->iph.frag_off & htons(~IP_DF)))
1265                 return -EINVAL;
1266 
1267         if (p->iph.ttl)
1268                 p->iph.frag_off |= htons(IP_DF);
1269         return 0;
1270 }
1271 
1272 static int
1273 ipip6_tunnel_get(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1274 {
1275         struct ip_tunnel *t = netdev_priv(dev);
1276 
1277         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev)
1278                 t = ipip6_tunnel_locate(t->net, p, 0);
1279         if (!t)
1280                 t = netdev_priv(dev);
1281         memcpy(p, &t->parms, sizeof(*p));
1282         return 0;
1283 }
1284 
1285 static int
1286 ipip6_tunnel_add(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1287 {
1288         struct ip_tunnel *t = netdev_priv(dev);
1289         int err;
1290 
1291         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1292         if (err)
1293                 return err;
1294 
1295         t = ipip6_tunnel_locate(t->net, p, 1);
1296         if (!t)
1297                 return -ENOBUFS;
1298         return 0;
1299 }
1300 
1301 static int
1302 ipip6_tunnel_change(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1303 {
1304         struct ip_tunnel *t = netdev_priv(dev);
1305         int err;
1306 
1307         err = __ipip6_tunnel_ioctl_validate(t->net, p);
1308         if (err)
1309                 return err;
1310 
1311         t = ipip6_tunnel_locate(t->net, p, 0);
1312         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1313                 if (!t)
1314                         return -ENOENT;
1315         } else {
1316                 if (t) {
1317                         if (t->dev != dev)
1318                                 return -EEXIST;
1319                 } else {
1320                         if (((dev->flags & IFF_POINTOPOINT) && !p->iph.daddr) ||
1321                             (!(dev->flags & IFF_POINTOPOINT) && p->iph.daddr))
1322                                 return -EINVAL;
1323                         t = netdev_priv(dev);
1324                 }
1325 
1326                 ipip6_tunnel_update(t, p, t->fwmark);
1327         }
1328 
1329         return 0;
1330 }
1331 
1332 static int
1333 ipip6_tunnel_del(struct net_device *dev, struct ip_tunnel_parm_kern *p)
1334 {
1335         struct ip_tunnel *t = netdev_priv(dev);
1336 
1337         if (!ns_capable(t->net->user_ns, CAP_NET_ADMIN))
1338                 return -EPERM;
1339 
1340         if (dev == dev_to_sit_net(dev)->fb_tunnel_dev) {
1341                 t = ipip6_tunnel_locate(t->net, p, 0);
1342                 if (!t)
1343                         return -ENOENT;
1344                 if (t == netdev_priv(dev_to_sit_net(dev)->fb_tunnel_dev))
1345                         return -EPERM;
1346                 dev = t->dev;
1347         }
1348         unregister_netdevice(dev);
1349         return 0;
1350 }
1351 
1352 static int
1353 ipip6_tunnel_ctl(struct net_device *dev, struct ip_tunnel_parm_kern *p,
1354                  int cmd)
1355 {
1356         switch (cmd) {
1357         case SIOCGETTUNNEL:
1358                 return ipip6_tunnel_get(dev, p);
1359         case SIOCADDTUNNEL:
1360                 return ipip6_tunnel_add(dev, p);
1361         case SIOCCHGTUNNEL:
1362                 return ipip6_tunnel_change(dev, p);
1363         case SIOCDELTUNNEL:
1364                 return ipip6_tunnel_del(dev, p);
1365         default:
1366                 return -EINVAL;
1367         }
1368 }
1369 
1370 static int
1371 ipip6_tunnel_siocdevprivate(struct net_device *dev, struct ifreq *ifr,
1372                             void __user *data, int cmd)
1373 {
1374         switch (cmd) {
1375         case SIOCGETTUNNEL:
1376         case SIOCADDTUNNEL:
1377         case SIOCCHGTUNNEL:
1378         case SIOCDELTUNNEL:
1379                 return ip_tunnel_siocdevprivate(dev, ifr, data, cmd);
1380         case SIOCGETPRL:
1381                 return ipip6_tunnel_get_prl(dev, data);
1382         case SIOCADDPRL:
1383         case SIOCDELPRL:
1384         case SIOCCHGPRL:
1385                 return ipip6_tunnel_prl_ctl(dev, data, cmd);
1386 #ifdef CONFIG_IPV6_SIT_6RD
1387         case SIOCGET6RD:
1388                 return ipip6_tunnel_get6rd(dev, data);
1389         case SIOCADD6RD:
1390         case SIOCCHG6RD:
1391         case SIOCDEL6RD:
1392                 return ipip6_tunnel_6rdctl(dev, data, cmd);
1393 #endif
1394         default:
1395                 return -EINVAL;
1396         }
1397 }
1398 
1399 static const struct net_device_ops ipip6_netdev_ops = {
1400         .ndo_init       = ipip6_tunnel_init,
1401         .ndo_uninit     = ipip6_tunnel_uninit,
1402         .ndo_start_xmit = sit_tunnel_xmit,
1403         .ndo_siocdevprivate = ipip6_tunnel_siocdevprivate,
1404         .ndo_get_iflink = ip_tunnel_get_iflink,
1405         .ndo_tunnel_ctl = ipip6_tunnel_ctl,
1406 };
1407 
1408 static void ipip6_dev_free(struct net_device *dev)
1409 {
1410         struct ip_tunnel *tunnel = netdev_priv(dev);
1411 
1412         dst_cache_destroy(&tunnel->dst_cache);
1413 }
1414 
1415 #define SIT_FEATURES (NETIF_F_SG           | \
1416                       NETIF_F_FRAGLIST     | \
1417                       NETIF_F_HIGHDMA      | \
1418                       NETIF_F_GSO_SOFTWARE | \
1419                       NETIF_F_HW_CSUM)
1420 
1421 static void ipip6_tunnel_setup(struct net_device *dev)
1422 {
1423         struct ip_tunnel *tunnel = netdev_priv(dev);
1424         int t_hlen = tunnel->hlen + sizeof(struct iphdr);
1425 
1426         dev->netdev_ops         = &ipip6_netdev_ops;
1427         dev->header_ops         = &ip_tunnel_header_ops;
1428         dev->needs_free_netdev  = true;
1429         dev->priv_destructor    = ipip6_dev_free;
1430 
1431         dev->type               = ARPHRD_SIT;
1432         dev->mtu                = ETH_DATA_LEN - t_hlen;
1433         dev->min_mtu            = IPV6_MIN_MTU;
1434         dev->max_mtu            = IP6_MAX_MTU - t_hlen;
1435         dev->flags              = IFF_NOARP;
1436         netif_keep_dst(dev);
1437         dev->addr_len           = 4;
1438         dev->features           |= NETIF_F_LLTX;
1439         dev->features           |= SIT_FEATURES;
1440         dev->hw_features        |= SIT_FEATURES;
1441         dev->pcpu_stat_type     = NETDEV_PCPU_STAT_TSTATS;
1442 
1443 }
1444 
1445 static int ipip6_tunnel_init(struct net_device *dev)
1446 {
1447         struct ip_tunnel *tunnel = netdev_priv(dev);
1448         int err;
1449 
1450         tunnel->dev = dev;
1451         tunnel->net = dev_net(dev);
1452         strcpy(tunnel->parms.name, dev->name);
1453 
1454         ipip6_tunnel_bind_dev(dev);
1455 
1456         err = dst_cache_init(&tunnel->dst_cache, GFP_KERNEL);
1457         if (err)
1458                 return err;
1459 
1460         netdev_hold(dev, &tunnel->dev_tracker, GFP_KERNEL);
1461         netdev_lockdep_set_classes(dev);
1462         return 0;
1463 }
1464 
1465 static void __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1466 {
1467         struct ip_tunnel *tunnel = netdev_priv(dev);
1468         struct iphdr *iph = &tunnel->parms.iph;
1469         struct net *net = dev_net(dev);
1470         struct sit_net *sitn = net_generic(net, sit_net_id);
1471 
1472         iph->version            = 4;
1473         iph->protocol           = IPPROTO_IPV6;
1474         iph->ihl                = 5;
1475         iph->ttl                = 64;
1476 
1477         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1478 }
1479 
1480 static int ipip6_validate(struct nlattr *tb[], struct nlattr *data[],
1481                           struct netlink_ext_ack *extack)
1482 {
1483         u8 proto;
1484 
1485         if (!data || !data[IFLA_IPTUN_PROTO])
1486                 return 0;
1487 
1488         proto = nla_get_u8(data[IFLA_IPTUN_PROTO]);
1489         if (!ipip6_valid_ip_proto(proto))
1490                 return -EINVAL;
1491 
1492         return 0;
1493 }
1494 
1495 static void ipip6_netlink_parms(struct nlattr *data[],
1496                                 struct ip_tunnel_parm_kern *parms,
1497                                 __u32 *fwmark)
1498 {
1499         memset(parms, 0, sizeof(*parms));
1500 
1501         parms->iph.version = 4;
1502         parms->iph.protocol = IPPROTO_IPV6;
1503         parms->iph.ihl = 5;
1504         parms->iph.ttl = 64;
1505 
1506         if (!data)
1507                 return;
1508 
1509         ip_tunnel_netlink_parms(data, parms);
1510 
1511         if (data[IFLA_IPTUN_FWMARK])
1512                 *fwmark = nla_get_u32(data[IFLA_IPTUN_FWMARK]);
1513 }
1514 
1515 #ifdef CONFIG_IPV6_SIT_6RD
1516 /* This function returns true when 6RD attributes are present in the nl msg */
1517 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1518                                     struct ip_tunnel_6rd *ip6rd)
1519 {
1520         bool ret = false;
1521         memset(ip6rd, 0, sizeof(*ip6rd));
1522 
1523         if (!data)
1524                 return ret;
1525 
1526         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1527                 ret = true;
1528                 ip6rd->prefix = nla_get_in6_addr(data[IFLA_IPTUN_6RD_PREFIX]);
1529         }
1530 
1531         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1532                 ret = true;
1533                 ip6rd->relay_prefix =
1534                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1535         }
1536 
1537         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1538                 ret = true;
1539                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1540         }
1541 
1542         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1543                 ret = true;
1544                 ip6rd->relay_prefixlen =
1545                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1546         }
1547 
1548         return ret;
1549 }
1550 #endif
1551 
1552 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1553                          struct nlattr *tb[], struct nlattr *data[],
1554                          struct netlink_ext_ack *extack)
1555 {
1556         struct net *net = dev_net(dev);
1557         struct ip_tunnel *nt;
1558         struct ip_tunnel_encap ipencap;
1559 #ifdef CONFIG_IPV6_SIT_6RD
1560         struct ip_tunnel_6rd ip6rd;
1561 #endif
1562         int err;
1563 
1564         nt = netdev_priv(dev);
1565 
1566         if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
1567                 err = ip_tunnel_encap_setup(nt, &ipencap);
1568                 if (err < 0)
1569                         return err;
1570         }
1571 
1572         ipip6_netlink_parms(data, &nt->parms, &nt->fwmark);
1573 
1574         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1575                 return -EEXIST;
1576 
1577         err = ipip6_tunnel_create(dev);
1578         if (err < 0)
1579                 return err;
1580 
1581         if (tb[IFLA_MTU]) {
1582                 u32 mtu = nla_get_u32(tb[IFLA_MTU]);
1583 
1584                 if (mtu >= IPV6_MIN_MTU &&
1585                     mtu <= IP6_MAX_MTU - dev->hard_header_len)
1586                         dev->mtu = mtu;
1587         }
1588 
1589 #ifdef CONFIG_IPV6_SIT_6RD
1590         if (ipip6_netlink_6rd_parms(data, &ip6rd)) {
1591                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1592                 if (err < 0)
1593                         unregister_netdevice_queue(dev, NULL);
1594         }
1595 #endif
1596 
1597         return err;
1598 }
1599 
1600 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1601                             struct nlattr *data[],
1602                             struct netlink_ext_ack *extack)
1603 {
1604         struct ip_tunnel *t = netdev_priv(dev);
1605         struct ip_tunnel_encap ipencap;
1606         struct ip_tunnel_parm_kern p;
1607         struct net *net = t->net;
1608         struct sit_net *sitn = net_generic(net, sit_net_id);
1609 #ifdef CONFIG_IPV6_SIT_6RD
1610         struct ip_tunnel_6rd ip6rd;
1611 #endif
1612         __u32 fwmark = t->fwmark;
1613         int err;
1614 
1615         if (dev == sitn->fb_tunnel_dev)
1616                 return -EINVAL;
1617 
1618         if (ip_tunnel_netlink_encap_parms(data, &ipencap)) {
1619                 err = ip_tunnel_encap_setup(t, &ipencap);
1620                 if (err < 0)
1621                         return err;
1622         }
1623 
1624         ipip6_netlink_parms(data, &p, &fwmark);
1625 
1626         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1627             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1628                 return -EINVAL;
1629 
1630         t = ipip6_tunnel_locate(net, &p, 0);
1631 
1632         if (t) {
1633                 if (t->dev != dev)
1634                         return -EEXIST;
1635         } else
1636                 t = netdev_priv(dev);
1637 
1638         ipip6_tunnel_update(t, &p, fwmark);
1639 
1640 #ifdef CONFIG_IPV6_SIT_6RD
1641         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1642                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1643 #endif
1644 
1645         return 0;
1646 }
1647 
1648 static size_t ipip6_get_size(const struct net_device *dev)
1649 {
1650         return
1651                 /* IFLA_IPTUN_LINK */
1652                 nla_total_size(4) +
1653                 /* IFLA_IPTUN_LOCAL */
1654                 nla_total_size(4) +
1655                 /* IFLA_IPTUN_REMOTE */
1656                 nla_total_size(4) +
1657                 /* IFLA_IPTUN_TTL */
1658                 nla_total_size(1) +
1659                 /* IFLA_IPTUN_TOS */
1660                 nla_total_size(1) +
1661                 /* IFLA_IPTUN_PMTUDISC */
1662                 nla_total_size(1) +
1663                 /* IFLA_IPTUN_FLAGS */
1664                 nla_total_size(2) +
1665                 /* IFLA_IPTUN_PROTO */
1666                 nla_total_size(1) +
1667 #ifdef CONFIG_IPV6_SIT_6RD
1668                 /* IFLA_IPTUN_6RD_PREFIX */
1669                 nla_total_size(sizeof(struct in6_addr)) +
1670                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1671                 nla_total_size(4) +
1672                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1673                 nla_total_size(2) +
1674                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1675                 nla_total_size(2) +
1676 #endif
1677                 /* IFLA_IPTUN_ENCAP_TYPE */
1678                 nla_total_size(2) +
1679                 /* IFLA_IPTUN_ENCAP_FLAGS */
1680                 nla_total_size(2) +
1681                 /* IFLA_IPTUN_ENCAP_SPORT */
1682                 nla_total_size(2) +
1683                 /* IFLA_IPTUN_ENCAP_DPORT */
1684                 nla_total_size(2) +
1685                 /* IFLA_IPTUN_FWMARK */
1686                 nla_total_size(4) +
1687                 0;
1688 }
1689 
1690 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1691 {
1692         struct ip_tunnel *tunnel = netdev_priv(dev);
1693         struct ip_tunnel_parm_kern *parm = &tunnel->parms;
1694 
1695         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1696             nla_put_in_addr(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1697             nla_put_in_addr(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1698             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1699             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1700             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1701                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1702             nla_put_u8(skb, IFLA_IPTUN_PROTO, parm->iph.protocol) ||
1703             nla_put_be16(skb, IFLA_IPTUN_FLAGS,
1704                          ip_tunnel_flags_to_be16(parm->i_flags)) ||
1705             nla_put_u32(skb, IFLA_IPTUN_FWMARK, tunnel->fwmark))
1706                 goto nla_put_failure;
1707 
1708 #ifdef CONFIG_IPV6_SIT_6RD
1709         if (nla_put_in6_addr(skb, IFLA_IPTUN_6RD_PREFIX,
1710                              &tunnel->ip6rd.prefix) ||
1711             nla_put_in_addr(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1712                             tunnel->ip6rd.relay_prefix) ||
1713             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1714                         tunnel->ip6rd.prefixlen) ||
1715             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1716                         tunnel->ip6rd.relay_prefixlen))
1717                 goto nla_put_failure;
1718 #endif
1719 
1720         if (nla_put_u16(skb, IFLA_IPTUN_ENCAP_TYPE,
1721                         tunnel->encap.type) ||
1722             nla_put_be16(skb, IFLA_IPTUN_ENCAP_SPORT,
1723                         tunnel->encap.sport) ||
1724             nla_put_be16(skb, IFLA_IPTUN_ENCAP_DPORT,
1725                         tunnel->encap.dport) ||
1726             nla_put_u16(skb, IFLA_IPTUN_ENCAP_FLAGS,
1727                         tunnel->encap.flags))
1728                 goto nla_put_failure;
1729 
1730         return 0;
1731 
1732 nla_put_failure:
1733         return -EMSGSIZE;
1734 }
1735 
1736 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1737         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1738         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1739         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1740         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1741         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1742         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1743         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1744         [IFLA_IPTUN_PROTO]              = { .type = NLA_U8 },
1745 #ifdef CONFIG_IPV6_SIT_6RD
1746         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1747         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1748         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1749         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1750 #endif
1751         [IFLA_IPTUN_ENCAP_TYPE]         = { .type = NLA_U16 },
1752         [IFLA_IPTUN_ENCAP_FLAGS]        = { .type = NLA_U16 },
1753         [IFLA_IPTUN_ENCAP_SPORT]        = { .type = NLA_U16 },
1754         [IFLA_IPTUN_ENCAP_DPORT]        = { .type = NLA_U16 },
1755         [IFLA_IPTUN_FWMARK]             = { .type = NLA_U32 },
1756 };
1757 
1758 static void ipip6_dellink(struct net_device *dev, struct list_head *head)
1759 {
1760         struct net *net = dev_net(dev);
1761         struct sit_net *sitn = net_generic(net, sit_net_id);
1762 
1763         if (dev != sitn->fb_tunnel_dev)
1764                 unregister_netdevice_queue(dev, head);
1765 }
1766 
1767 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1768         .kind           = "sit",
1769         .maxtype        = IFLA_IPTUN_MAX,
1770         .policy         = ipip6_policy,
1771         .priv_size      = sizeof(struct ip_tunnel),
1772         .setup          = ipip6_tunnel_setup,
1773         .validate       = ipip6_validate,
1774         .newlink        = ipip6_newlink,
1775         .changelink     = ipip6_changelink,
1776         .get_size       = ipip6_get_size,
1777         .fill_info      = ipip6_fill_info,
1778         .dellink        = ipip6_dellink,
1779         .get_link_net   = ip_tunnel_get_link_net,
1780 };
1781 
1782 static struct xfrm_tunnel sit_handler __read_mostly = {
1783         .handler        =       ipip6_rcv,
1784         .err_handler    =       ipip6_err,
1785         .priority       =       1,
1786 };
1787 
1788 static struct xfrm_tunnel ipip_handler __read_mostly = {
1789         .handler        =       ipip_rcv,
1790         .err_handler    =       ipip6_err,
1791         .priority       =       2,
1792 };
1793 
1794 #if IS_ENABLED(CONFIG_MPLS)
1795 static struct xfrm_tunnel mplsip_handler __read_mostly = {
1796         .handler        =       mplsip_rcv,
1797         .err_handler    =       ipip6_err,
1798         .priority       =       2,
1799 };
1800 #endif
1801 
1802 static void __net_exit sit_destroy_tunnels(struct net *net,
1803                                            struct list_head *head)
1804 {
1805         struct sit_net *sitn = net_generic(net, sit_net_id);
1806         struct net_device *dev, *aux;
1807         int prio;
1808 
1809         for_each_netdev_safe(net, dev, aux)
1810                 if (dev->rtnl_link_ops == &sit_link_ops)
1811                         unregister_netdevice_queue(dev, head);
1812 
1813         for (prio = 0; prio < 4; prio++) {
1814                 int h;
1815                 for (h = 0; h < (prio ? IP6_SIT_HASH_SIZE : 1); h++) {
1816                         struct ip_tunnel *t;
1817 
1818                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1819                         while (t) {
1820                                 /* If dev is in the same netns, it has already
1821                                  * been added to the list by the previous loop.
1822                                  */
1823                                 if (!net_eq(dev_net(t->dev), net))
1824                                         unregister_netdevice_queue(t->dev,
1825                                                                    head);
1826                                 t = rtnl_dereference(t->next);
1827                         }
1828                 }
1829         }
1830 }
1831 
1832 static int __net_init sit_init_net(struct net *net)
1833 {
1834         struct sit_net *sitn = net_generic(net, sit_net_id);
1835         struct ip_tunnel *t;
1836         int err;
1837 
1838         sitn->tunnels[0] = sitn->tunnels_wc;
1839         sitn->tunnels[1] = sitn->tunnels_l;
1840         sitn->tunnels[2] = sitn->tunnels_r;
1841         sitn->tunnels[3] = sitn->tunnels_r_l;
1842 
1843         if (!net_has_fallback_tunnels(net))
1844                 return 0;
1845 
1846         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1847                                            NET_NAME_UNKNOWN,
1848                                            ipip6_tunnel_setup);
1849         if (!sitn->fb_tunnel_dev) {
1850                 err = -ENOMEM;
1851                 goto err_alloc_dev;
1852         }
1853         dev_net_set(sitn->fb_tunnel_dev, net);
1854         sitn->fb_tunnel_dev->rtnl_link_ops = &sit_link_ops;
1855         /* FB netdevice is special: we have one, and only one per netns.
1856          * Allowing to move it to another netns is clearly unsafe.
1857          */
1858         sitn->fb_tunnel_dev->features |= NETIF_F_NETNS_LOCAL;
1859 
1860         err = register_netdev(sitn->fb_tunnel_dev);
1861         if (err)
1862                 goto err_reg_dev;
1863 
1864         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1865         ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1866 
1867         t = netdev_priv(sitn->fb_tunnel_dev);
1868 
1869         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1870         return 0;
1871 
1872 err_reg_dev:
1873         free_netdev(sitn->fb_tunnel_dev);
1874 err_alloc_dev:
1875         return err;
1876 }
1877 
1878 static void __net_exit sit_exit_batch_rtnl(struct list_head *net_list,
1879                                            struct list_head *dev_to_kill)
1880 {
1881         struct net *net;
1882 
1883         ASSERT_RTNL();
1884         list_for_each_entry(net, net_list, exit_list)
1885                 sit_destroy_tunnels(net, dev_to_kill);
1886 }
1887 
1888 static struct pernet_operations sit_net_ops = {
1889         .init = sit_init_net,
1890         .exit_batch_rtnl = sit_exit_batch_rtnl,
1891         .id   = &sit_net_id,
1892         .size = sizeof(struct sit_net),
1893 };
1894 
1895 static void __exit sit_cleanup(void)
1896 {
1897         rtnl_link_unregister(&sit_link_ops);
1898         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1899         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1900 #if IS_ENABLED(CONFIG_MPLS)
1901         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1902 #endif
1903 
1904         unregister_pernet_device(&sit_net_ops);
1905         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1906 }
1907 
1908 static int __init sit_init(void)
1909 {
1910         int err;
1911 
1912         pr_info("IPv6, IPv4 and MPLS over IPv4 tunneling driver\n");
1913 
1914         err = register_pernet_device(&sit_net_ops);
1915         if (err < 0)
1916                 return err;
1917         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1918         if (err < 0) {
1919                 pr_info("%s: can't register ip6ip4\n", __func__);
1920                 goto xfrm_tunnel_failed;
1921         }
1922         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
1923         if (err < 0) {
1924                 pr_info("%s: can't register ip4ip4\n", __func__);
1925                 goto xfrm_tunnel4_failed;
1926         }
1927 #if IS_ENABLED(CONFIG_MPLS)
1928         err = xfrm4_tunnel_register(&mplsip_handler, AF_MPLS);
1929         if (err < 0) {
1930                 pr_info("%s: can't register mplsip\n", __func__);
1931                 goto xfrm_tunnel_mpls_failed;
1932         }
1933 #endif
1934         err = rtnl_link_register(&sit_link_ops);
1935         if (err < 0)
1936                 goto rtnl_link_failed;
1937 
1938 out:
1939         return err;
1940 
1941 rtnl_link_failed:
1942 #if IS_ENABLED(CONFIG_MPLS)
1943         xfrm4_tunnel_deregister(&mplsip_handler, AF_MPLS);
1944 xfrm_tunnel_mpls_failed:
1945 #endif
1946         xfrm4_tunnel_deregister(&ipip_handler, AF_INET);
1947 xfrm_tunnel4_failed:
1948         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1949 xfrm_tunnel_failed:
1950         unregister_pernet_device(&sit_net_ops);
1951         goto out;
1952 }
1953 
1954 module_init(sit_init);
1955 module_exit(sit_cleanup);
1956 MODULE_DESCRIPTION("IPv6-in-IPv4 tunnel SIT driver");
1957 MODULE_LICENSE("GPL");
1958 MODULE_ALIAS_RTNL_LINK("sit");
1959 MODULE_ALIAS_NETDEV("sit0");
1960 

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