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

Version: ~ [ linux-5.3-rc5 ] ~ [ linux-5.2.9 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.67 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.139 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.189 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.189 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.72 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /*
  2  *      IPv6 over IPv4 tunnel device - Simple Internet Transition (SIT)
  3  *      Linux INET6 implementation
  4  *
  5  *      Authors:
  6  *      Pedro Roque             <roque@di.fc.ul.pt>
  7  *      Alexey Kuznetsov        <kuznet@ms2.inr.ac.ru>
  8  *
  9  *      This program is free software; you can redistribute it and/or
 10  *      modify it under the terms of the GNU General Public License
 11  *      as published by the Free Software Foundation; either version
 12  *      2 of the License, or (at your option) any later version.
 13  *
 14  *      Changes:
 15  * Roger Venning <r.venning@telstra.com>:       6to4 support
 16  * Nate Thompson <nate@thebog.net>:             6to4 support
 17  * Fred Templin <fred.l.templin@boeing.com>:    isatap support
 18  */
 19 
 20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 21 
 22 #include <linux/module.h>
 23 #include <linux/capability.h>
 24 #include <linux/errno.h>
 25 #include <linux/types.h>
 26 #include <linux/socket.h>
 27 #include <linux/sockios.h>
 28 #include <linux/net.h>
 29 #include <linux/in6.h>
 30 #include <linux/netdevice.h>
 31 #include <linux/if_arp.h>
 32 #include <linux/icmp.h>
 33 #include <linux/slab.h>
 34 #include <asm/uaccess.h>
 35 #include <linux/init.h>
 36 #include <linux/netfilter_ipv4.h>
 37 #include <linux/if_ether.h>
 38 
 39 #include <net/sock.h>
 40 #include <net/snmp.h>
 41 
 42 #include <net/ipv6.h>
 43 #include <net/protocol.h>
 44 #include <net/transp_v6.h>
 45 #include <net/ip6_fib.h>
 46 #include <net/ip6_route.h>
 47 #include <net/ndisc.h>
 48 #include <net/addrconf.h>
 49 #include <net/ip.h>
 50 #include <net/udp.h>
 51 #include <net/icmp.h>
 52 #include <net/ipip.h>
 53 #include <net/inet_ecn.h>
 54 #include <net/xfrm.h>
 55 #include <net/dsfield.h>
 56 #include <net/net_namespace.h>
 57 #include <net/netns/generic.h>
 58 
 59 /*
 60    This version of net/ipv6/sit.c is cloned of net/ipv4/ip_gre.c
 61 
 62    For comments look at net/ipv4/ip_gre.c --ANK
 63  */
 64 
 65 #define HASH_SIZE  16
 66 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
 67 
 68 static bool log_ecn_error = true;
 69 module_param(log_ecn_error, bool, 0644);
 70 MODULE_PARM_DESC(log_ecn_error, "Log packets received with corrupted ECN");
 71 
 72 static int ipip6_tunnel_init(struct net_device *dev);
 73 static void ipip6_tunnel_setup(struct net_device *dev);
 74 static void ipip6_dev_free(struct net_device *dev);
 75 static struct rtnl_link_ops sit_link_ops __read_mostly;
 76 
 77 static int sit_net_id __read_mostly;
 78 struct sit_net {
 79         struct ip_tunnel __rcu *tunnels_r_l[HASH_SIZE];
 80         struct ip_tunnel __rcu *tunnels_r[HASH_SIZE];
 81         struct ip_tunnel __rcu *tunnels_l[HASH_SIZE];
 82         struct ip_tunnel __rcu *tunnels_wc[1];
 83         struct ip_tunnel __rcu **tunnels[4];
 84 
 85         struct net_device *fb_tunnel_dev;
 86 };
 87 
 88 static struct rtnl_link_stats64 *ipip6_get_stats64(struct net_device *dev,
 89                                                    struct rtnl_link_stats64 *tot)
 90 {
 91         int i;
 92 
 93         for_each_possible_cpu(i) {
 94                 const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 95                 u64 rx_packets, rx_bytes, tx_packets, tx_bytes;
 96                 unsigned int start;
 97 
 98                 do {
 99                         start = u64_stats_fetch_begin_bh(&tstats->syncp);
100                         rx_packets = tstats->rx_packets;
101                         tx_packets = tstats->tx_packets;
102                         rx_bytes = tstats->rx_bytes;
103                         tx_bytes = tstats->tx_bytes;
104                 } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
105 
106                 tot->rx_packets += rx_packets;
107                 tot->tx_packets += tx_packets;
108                 tot->rx_bytes   += rx_bytes;
109                 tot->tx_bytes   += tx_bytes;
110         }
111 
112         tot->rx_errors = dev->stats.rx_errors;
113         tot->rx_frame_errors = dev->stats.rx_frame_errors;
114         tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
115         tot->tx_carrier_errors = dev->stats.tx_carrier_errors;
116         tot->tx_dropped = dev->stats.tx_dropped;
117         tot->tx_aborted_errors = dev->stats.tx_aborted_errors;
118         tot->tx_errors = dev->stats.tx_errors;
119 
120         return tot;
121 }
122 
123 /*
124  * Must be invoked with rcu_read_lock
125  */
126 static struct ip_tunnel *ipip6_tunnel_lookup(struct net *net,
127                 struct net_device *dev, __be32 remote, __be32 local)
128 {
129         unsigned int h0 = HASH(remote);
130         unsigned int h1 = HASH(local);
131         struct ip_tunnel *t;
132         struct sit_net *sitn = net_generic(net, sit_net_id);
133 
134         for_each_ip_tunnel_rcu(t, sitn->tunnels_r_l[h0 ^ h1]) {
135                 if (local == t->parms.iph.saddr &&
136                     remote == t->parms.iph.daddr &&
137                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
138                     (t->dev->flags & IFF_UP))
139                         return t;
140         }
141         for_each_ip_tunnel_rcu(t, sitn->tunnels_r[h0]) {
142                 if (remote == t->parms.iph.daddr &&
143                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
144                     (t->dev->flags & IFF_UP))
145                         return t;
146         }
147         for_each_ip_tunnel_rcu(t, sitn->tunnels_l[h1]) {
148                 if (local == t->parms.iph.saddr &&
149                     (!dev || !t->parms.link || dev->iflink == t->parms.link) &&
150                     (t->dev->flags & IFF_UP))
151                         return t;
152         }
153         t = rcu_dereference(sitn->tunnels_wc[0]);
154         if ((t != NULL) && (t->dev->flags & IFF_UP))
155                 return t;
156         return NULL;
157 }
158 
159 static struct ip_tunnel __rcu **__ipip6_bucket(struct sit_net *sitn,
160                 struct ip_tunnel_parm *parms)
161 {
162         __be32 remote = parms->iph.daddr;
163         __be32 local = parms->iph.saddr;
164         unsigned int h = 0;
165         int prio = 0;
166 
167         if (remote) {
168                 prio |= 2;
169                 h ^= HASH(remote);
170         }
171         if (local) {
172                 prio |= 1;
173                 h ^= HASH(local);
174         }
175         return &sitn->tunnels[prio][h];
176 }
177 
178 static inline struct ip_tunnel __rcu **ipip6_bucket(struct sit_net *sitn,
179                 struct ip_tunnel *t)
180 {
181         return __ipip6_bucket(sitn, &t->parms);
182 }
183 
184 static void ipip6_tunnel_unlink(struct sit_net *sitn, struct ip_tunnel *t)
185 {
186         struct ip_tunnel __rcu **tp;
187         struct ip_tunnel *iter;
188 
189         for (tp = ipip6_bucket(sitn, t);
190              (iter = rtnl_dereference(*tp)) != NULL;
191              tp = &iter->next) {
192                 if (t == iter) {
193                         rcu_assign_pointer(*tp, t->next);
194                         break;
195                 }
196         }
197 }
198 
199 static void ipip6_tunnel_link(struct sit_net *sitn, struct ip_tunnel *t)
200 {
201         struct ip_tunnel __rcu **tp = ipip6_bucket(sitn, t);
202 
203         rcu_assign_pointer(t->next, rtnl_dereference(*tp));
204         rcu_assign_pointer(*tp, t);
205 }
206 
207 static void ipip6_tunnel_clone_6rd(struct net_device *dev, struct sit_net *sitn)
208 {
209 #ifdef CONFIG_IPV6_SIT_6RD
210         struct ip_tunnel *t = netdev_priv(dev);
211 
212         if (t->dev == sitn->fb_tunnel_dev) {
213                 ipv6_addr_set(&t->ip6rd.prefix, htonl(0x20020000), 0, 0, 0);
214                 t->ip6rd.relay_prefix = 0;
215                 t->ip6rd.prefixlen = 16;
216                 t->ip6rd.relay_prefixlen = 0;
217         } else {
218                 struct ip_tunnel *t0 = netdev_priv(sitn->fb_tunnel_dev);
219                 memcpy(&t->ip6rd, &t0->ip6rd, sizeof(t->ip6rd));
220         }
221 #endif
222 }
223 
224 static int ipip6_tunnel_create(struct net_device *dev)
225 {
226         struct ip_tunnel *t = netdev_priv(dev);
227         struct net *net = dev_net(dev);
228         struct sit_net *sitn = net_generic(net, sit_net_id);
229         int err;
230 
231         err = ipip6_tunnel_init(dev);
232         if (err < 0)
233                 goto out;
234         ipip6_tunnel_clone_6rd(dev, sitn);
235 
236         if ((__force u16)t->parms.i_flags & SIT_ISATAP)
237                 dev->priv_flags |= IFF_ISATAP;
238 
239         err = register_netdevice(dev);
240         if (err < 0)
241                 goto out;
242 
243         strcpy(t->parms.name, dev->name);
244         dev->rtnl_link_ops = &sit_link_ops;
245 
246         dev_hold(dev);
247 
248         ipip6_tunnel_link(sitn, t);
249         return 0;
250 
251 out:
252         return err;
253 }
254 
255 static struct ip_tunnel *ipip6_tunnel_locate(struct net *net,
256                 struct ip_tunnel_parm *parms, int create)
257 {
258         __be32 remote = parms->iph.daddr;
259         __be32 local = parms->iph.saddr;
260         struct ip_tunnel *t, *nt;
261         struct ip_tunnel __rcu **tp;
262         struct net_device *dev;
263         char name[IFNAMSIZ];
264         struct sit_net *sitn = net_generic(net, sit_net_id);
265 
266         for (tp = __ipip6_bucket(sitn, parms);
267             (t = rtnl_dereference(*tp)) != NULL;
268              tp = &t->next) {
269                 if (local == t->parms.iph.saddr &&
270                     remote == t->parms.iph.daddr &&
271                     parms->link == t->parms.link) {
272                         if (create)
273                                 return NULL;
274                         else
275                                 return t;
276                 }
277         }
278         if (!create)
279                 goto failed;
280 
281         if (parms->name[0])
282                 strlcpy(name, parms->name, IFNAMSIZ);
283         else
284                 strcpy(name, "sit%d");
285 
286         dev = alloc_netdev(sizeof(*t), name, ipip6_tunnel_setup);
287         if (dev == NULL)
288                 return NULL;
289 
290         dev_net_set(dev, net);
291 
292         nt = netdev_priv(dev);
293 
294         nt->parms = *parms;
295         if (ipip6_tunnel_create(dev) < 0)
296                 goto failed_free;
297 
298         return nt;
299 
300 failed_free:
301         ipip6_dev_free(dev);
302 failed:
303         return NULL;
304 }
305 
306 #define for_each_prl_rcu(start)                 \
307         for (prl = rcu_dereference(start);      \
308              prl;                               \
309              prl = rcu_dereference(prl->next))
310 
311 static struct ip_tunnel_prl_entry *
312 __ipip6_tunnel_locate_prl(struct ip_tunnel *t, __be32 addr)
313 {
314         struct ip_tunnel_prl_entry *prl;
315 
316         for_each_prl_rcu(t->prl)
317                 if (prl->addr == addr)
318                         break;
319         return prl;
320 
321 }
322 
323 static int ipip6_tunnel_get_prl(struct ip_tunnel *t,
324                                 struct ip_tunnel_prl __user *a)
325 {
326         struct ip_tunnel_prl kprl, *kp;
327         struct ip_tunnel_prl_entry *prl;
328         unsigned int cmax, c = 0, ca, len;
329         int ret = 0;
330 
331         if (copy_from_user(&kprl, a, sizeof(kprl)))
332                 return -EFAULT;
333         cmax = kprl.datalen / sizeof(kprl);
334         if (cmax > 1 && kprl.addr != htonl(INADDR_ANY))
335                 cmax = 1;
336 
337         /* For simple GET or for root users,
338          * we try harder to allocate.
339          */
340         kp = (cmax <= 1 || capable(CAP_NET_ADMIN)) ?
341                 kcalloc(cmax, sizeof(*kp), GFP_KERNEL) :
342                 NULL;
343 
344         rcu_read_lock();
345 
346         ca = t->prl_count < cmax ? t->prl_count : cmax;
347 
348         if (!kp) {
349                 /* We don't try hard to allocate much memory for
350                  * non-root users.
351                  * For root users, retry allocating enough memory for
352                  * the answer.
353                  */
354                 kp = kcalloc(ca, sizeof(*kp), GFP_ATOMIC);
355                 if (!kp) {
356                         ret = -ENOMEM;
357                         goto out;
358                 }
359         }
360 
361         c = 0;
362         for_each_prl_rcu(t->prl) {
363                 if (c >= cmax)
364                         break;
365                 if (kprl.addr != htonl(INADDR_ANY) && prl->addr != kprl.addr)
366                         continue;
367                 kp[c].addr = prl->addr;
368                 kp[c].flags = prl->flags;
369                 c++;
370                 if (kprl.addr != htonl(INADDR_ANY))
371                         break;
372         }
373 out:
374         rcu_read_unlock();
375 
376         len = sizeof(*kp) * c;
377         ret = 0;
378         if ((len && copy_to_user(a + 1, kp, len)) || put_user(len, &a->datalen))
379                 ret = -EFAULT;
380 
381         kfree(kp);
382 
383         return ret;
384 }
385 
386 static int
387 ipip6_tunnel_add_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a, int chg)
388 {
389         struct ip_tunnel_prl_entry *p;
390         int err = 0;
391 
392         if (a->addr == htonl(INADDR_ANY))
393                 return -EINVAL;
394 
395         ASSERT_RTNL();
396 
397         for (p = rtnl_dereference(t->prl); p; p = rtnl_dereference(p->next)) {
398                 if (p->addr == a->addr) {
399                         if (chg) {
400                                 p->flags = a->flags;
401                                 goto out;
402                         }
403                         err = -EEXIST;
404                         goto out;
405                 }
406         }
407 
408         if (chg) {
409                 err = -ENXIO;
410                 goto out;
411         }
412 
413         p = kzalloc(sizeof(struct ip_tunnel_prl_entry), GFP_KERNEL);
414         if (!p) {
415                 err = -ENOBUFS;
416                 goto out;
417         }
418 
419         p->next = t->prl;
420         p->addr = a->addr;
421         p->flags = a->flags;
422         t->prl_count++;
423         rcu_assign_pointer(t->prl, p);
424 out:
425         return err;
426 }
427 
428 static void prl_list_destroy_rcu(struct rcu_head *head)
429 {
430         struct ip_tunnel_prl_entry *p, *n;
431 
432         p = container_of(head, struct ip_tunnel_prl_entry, rcu_head);
433         do {
434                 n = rcu_dereference_protected(p->next, 1);
435                 kfree(p);
436                 p = n;
437         } while (p);
438 }
439 
440 static int
441 ipip6_tunnel_del_prl(struct ip_tunnel *t, struct ip_tunnel_prl *a)
442 {
443         struct ip_tunnel_prl_entry *x;
444         struct ip_tunnel_prl_entry __rcu **p;
445         int err = 0;
446 
447         ASSERT_RTNL();
448 
449         if (a && a->addr != htonl(INADDR_ANY)) {
450                 for (p = &t->prl;
451                      (x = rtnl_dereference(*p)) != NULL;
452                      p = &x->next) {
453                         if (x->addr == a->addr) {
454                                 *p = x->next;
455                                 kfree_rcu(x, rcu_head);
456                                 t->prl_count--;
457                                 goto out;
458                         }
459                 }
460                 err = -ENXIO;
461         } else {
462                 x = rtnl_dereference(t->prl);
463                 if (x) {
464                         t->prl_count = 0;
465                         call_rcu(&x->rcu_head, prl_list_destroy_rcu);
466                         t->prl = NULL;
467                 }
468         }
469 out:
470         return err;
471 }
472 
473 static int
474 isatap_chksrc(struct sk_buff *skb, const struct iphdr *iph, struct ip_tunnel *t)
475 {
476         struct ip_tunnel_prl_entry *p;
477         int ok = 1;
478 
479         rcu_read_lock();
480         p = __ipip6_tunnel_locate_prl(t, iph->saddr);
481         if (p) {
482                 if (p->flags & PRL_DEFAULT)
483                         skb->ndisc_nodetype = NDISC_NODETYPE_DEFAULT;
484                 else
485                         skb->ndisc_nodetype = NDISC_NODETYPE_NODEFAULT;
486         } else {
487                 const struct in6_addr *addr6 = &ipv6_hdr(skb)->saddr;
488 
489                 if (ipv6_addr_is_isatap(addr6) &&
490                     (addr6->s6_addr32[3] == iph->saddr) &&
491                     ipv6_chk_prefix(addr6, t->dev))
492                         skb->ndisc_nodetype = NDISC_NODETYPE_HOST;
493                 else
494                         ok = 0;
495         }
496         rcu_read_unlock();
497         return ok;
498 }
499 
500 static void ipip6_tunnel_uninit(struct net_device *dev)
501 {
502         struct net *net = dev_net(dev);
503         struct sit_net *sitn = net_generic(net, sit_net_id);
504 
505         if (dev == sitn->fb_tunnel_dev) {
506                 RCU_INIT_POINTER(sitn->tunnels_wc[0], NULL);
507         } else {
508                 ipip6_tunnel_unlink(sitn, netdev_priv(dev));
509                 ipip6_tunnel_del_prl(netdev_priv(dev), NULL);
510         }
511         dev_put(dev);
512 }
513 
514 
515 static int ipip6_err(struct sk_buff *skb, u32 info)
516 {
517 
518 /* All the routers (except for Linux) return only
519    8 bytes of packet payload. It means, that precise relaying of
520    ICMP in the real Internet is absolutely infeasible.
521  */
522         const struct iphdr *iph = (const struct iphdr *)skb->data;
523         const int type = icmp_hdr(skb)->type;
524         const int code = icmp_hdr(skb)->code;
525         struct ip_tunnel *t;
526         int err;
527 
528         switch (type) {
529         default:
530         case ICMP_PARAMETERPROB:
531                 return 0;
532 
533         case ICMP_DEST_UNREACH:
534                 switch (code) {
535                 case ICMP_SR_FAILED:
536                 case ICMP_PORT_UNREACH:
537                         /* Impossible event. */
538                         return 0;
539                 default:
540                         /* All others are translated to HOST_UNREACH.
541                            rfc2003 contains "deep thoughts" about NET_UNREACH,
542                            I believe they are just ether pollution. --ANK
543                          */
544                         break;
545                 }
546                 break;
547         case ICMP_TIME_EXCEEDED:
548                 if (code != ICMP_EXC_TTL)
549                         return 0;
550                 break;
551         case ICMP_REDIRECT:
552                 break;
553         }
554 
555         err = -ENOENT;
556 
557         t = ipip6_tunnel_lookup(dev_net(skb->dev),
558                                 skb->dev,
559                                 iph->daddr,
560                                 iph->saddr);
561         if (t == NULL)
562                 goto out;
563 
564         if (type == ICMP_DEST_UNREACH && code == ICMP_FRAG_NEEDED) {
565                 ipv4_update_pmtu(skb, dev_net(skb->dev), info,
566                                  t->dev->ifindex, 0, IPPROTO_IPV6, 0);
567                 err = 0;
568                 goto out;
569         }
570         if (type == ICMP_REDIRECT) {
571                 ipv4_redirect(skb, dev_net(skb->dev), t->dev->ifindex, 0,
572                               IPPROTO_IPV6, 0);
573                 err = 0;
574                 goto out;
575         }
576 
577         if (t->parms.iph.daddr == 0)
578                 goto out;
579 
580         err = 0;
581         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
582                 goto out;
583 
584         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
585                 t->err_count++;
586         else
587                 t->err_count = 1;
588         t->err_time = jiffies;
589 out:
590         return err;
591 }
592 
593 static int ipip6_rcv(struct sk_buff *skb)
594 {
595         const struct iphdr *iph;
596         struct ip_tunnel *tunnel;
597         int err;
598 
599         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
600                 goto out;
601 
602         iph = ip_hdr(skb);
603 
604         tunnel = ipip6_tunnel_lookup(dev_net(skb->dev), skb->dev,
605                                      iph->saddr, iph->daddr);
606         if (tunnel != NULL) {
607                 struct pcpu_tstats *tstats;
608 
609                 secpath_reset(skb);
610                 skb->mac_header = skb->network_header;
611                 skb_reset_network_header(skb);
612                 IPCB(skb)->flags = 0;
613                 skb->protocol = htons(ETH_P_IPV6);
614                 skb->pkt_type = PACKET_HOST;
615 
616                 if ((tunnel->dev->priv_flags & IFF_ISATAP) &&
617                     !isatap_chksrc(skb, iph, tunnel)) {
618                         tunnel->dev->stats.rx_errors++;
619                         goto out;
620                 }
621 
622                 __skb_tunnel_rx(skb, tunnel->dev);
623 
624                 err = IP_ECN_decapsulate(iph, skb);
625                 if (unlikely(err)) {
626                         if (log_ecn_error)
627                                 net_info_ratelimited("non-ECT from %pI4 with TOS=%#x\n",
628                                                      &iph->saddr, iph->tos);
629                         if (err > 1) {
630                                 ++tunnel->dev->stats.rx_frame_errors;
631                                 ++tunnel->dev->stats.rx_errors;
632                                 goto out;
633                         }
634                 }
635 
636                 tstats = this_cpu_ptr(tunnel->dev->tstats);
637                 tstats->rx_packets++;
638                 tstats->rx_bytes += skb->len;
639 
640                 netif_rx(skb);
641 
642                 return 0;
643         }
644 
645         /* no tunnel matched,  let upstream know, ipsec may handle it */
646         return 1;
647 out:
648         kfree_skb(skb);
649         return 0;
650 }
651 
652 /*
653  * Returns the embedded IPv4 address if the IPv6 address
654  * comes from 6rd / 6to4 (RFC 3056) addr space.
655  */
656 static inline
657 __be32 try_6rd(const struct in6_addr *v6dst, struct ip_tunnel *tunnel)
658 {
659         __be32 dst = 0;
660 
661 #ifdef CONFIG_IPV6_SIT_6RD
662         if (ipv6_prefix_equal(v6dst, &tunnel->ip6rd.prefix,
663                               tunnel->ip6rd.prefixlen)) {
664                 unsigned int pbw0, pbi0;
665                 int pbi1;
666                 u32 d;
667 
668                 pbw0 = tunnel->ip6rd.prefixlen >> 5;
669                 pbi0 = tunnel->ip6rd.prefixlen & 0x1f;
670 
671                 d = (ntohl(v6dst->s6_addr32[pbw0]) << pbi0) >>
672                     tunnel->ip6rd.relay_prefixlen;
673 
674                 pbi1 = pbi0 - tunnel->ip6rd.relay_prefixlen;
675                 if (pbi1 > 0)
676                         d |= ntohl(v6dst->s6_addr32[pbw0 + 1]) >>
677                              (32 - pbi1);
678 
679                 dst = tunnel->ip6rd.relay_prefix | htonl(d);
680         }
681 #else
682         if (v6dst->s6_addr16[0] == htons(0x2002)) {
683                 /* 6to4 v6 addr has 16 bits prefix, 32 v4addr, 16 SLA, ... */
684                 memcpy(&dst, &v6dst->s6_addr16[1], 4);
685         }
686 #endif
687         return dst;
688 }
689 
690 /*
691  *      This function assumes it is being called from dev_queue_xmit()
692  *      and that skb is filled properly by that function.
693  */
694 
695 static netdev_tx_t ipip6_tunnel_xmit(struct sk_buff *skb,
696                                      struct net_device *dev)
697 {
698         struct ip_tunnel *tunnel = netdev_priv(dev);
699         const struct iphdr  *tiph = &tunnel->parms.iph;
700         const struct ipv6hdr *iph6 = ipv6_hdr(skb);
701         u8     tos = tunnel->parms.iph.tos;
702         __be16 df = tiph->frag_off;
703         struct rtable *rt;                      /* Route to the other host */
704         struct net_device *tdev;                /* Device to other host */
705         struct iphdr  *iph;                     /* Our new IP header */
706         unsigned int max_headroom;              /* The extra header space needed */
707         __be32 dst = tiph->daddr;
708         struct flowi4 fl4;
709         int    mtu;
710         const struct in6_addr *addr6;
711         int addr_type;
712 
713         if (skb->protocol != htons(ETH_P_IPV6))
714                 goto tx_error;
715 
716         if (tos == 1)
717                 tos = ipv6_get_dsfield(iph6);
718 
719         /* ISATAP (RFC4214) - must come before 6to4 */
720         if (dev->priv_flags & IFF_ISATAP) {
721                 struct neighbour *neigh = NULL;
722                 bool do_tx_error = false;
723 
724                 if (skb_dst(skb))
725                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
726 
727                 if (neigh == NULL) {
728                         net_dbg_ratelimited("sit: nexthop == NULL\n");
729                         goto tx_error;
730                 }
731 
732                 addr6 = (const struct in6_addr *)&neigh->primary_key;
733                 addr_type = ipv6_addr_type(addr6);
734 
735                 if ((addr_type & IPV6_ADDR_UNICAST) &&
736                      ipv6_addr_is_isatap(addr6))
737                         dst = addr6->s6_addr32[3];
738                 else
739                         do_tx_error = true;
740 
741                 neigh_release(neigh);
742                 if (do_tx_error)
743                         goto tx_error;
744         }
745 
746         if (!dst)
747                 dst = try_6rd(&iph6->daddr, tunnel);
748 
749         if (!dst) {
750                 struct neighbour *neigh = NULL;
751                 bool do_tx_error = false;
752 
753                 if (skb_dst(skb))
754                         neigh = dst_neigh_lookup(skb_dst(skb), &iph6->daddr);
755 
756                 if (neigh == NULL) {
757                         net_dbg_ratelimited("sit: nexthop == NULL\n");
758                         goto tx_error;
759                 }
760 
761                 addr6 = (const struct in6_addr *)&neigh->primary_key;
762                 addr_type = ipv6_addr_type(addr6);
763 
764                 if (addr_type == IPV6_ADDR_ANY) {
765                         addr6 = &ipv6_hdr(skb)->daddr;
766                         addr_type = ipv6_addr_type(addr6);
767                 }
768 
769                 if ((addr_type & IPV6_ADDR_COMPATv4) != 0)
770                         dst = addr6->s6_addr32[3];
771                 else
772                         do_tx_error = true;
773 
774                 neigh_release(neigh);
775                 if (do_tx_error)
776                         goto tx_error;
777         }
778 
779         rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
780                                    dst, tiph->saddr,
781                                    0, 0,
782                                    IPPROTO_IPV6, RT_TOS(tos),
783                                    tunnel->parms.link);
784         if (IS_ERR(rt)) {
785                 dev->stats.tx_carrier_errors++;
786                 goto tx_error_icmp;
787         }
788         if (rt->rt_type != RTN_UNICAST) {
789                 ip_rt_put(rt);
790                 dev->stats.tx_carrier_errors++;
791                 goto tx_error_icmp;
792         }
793         tdev = rt->dst.dev;
794 
795         if (tdev == dev) {
796                 ip_rt_put(rt);
797                 dev->stats.collisions++;
798                 goto tx_error;
799         }
800 
801         if (df) {
802                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
803 
804                 if (mtu < 68) {
805                         dev->stats.collisions++;
806                         ip_rt_put(rt);
807                         goto tx_error;
808                 }
809 
810                 if (mtu < IPV6_MIN_MTU) {
811                         mtu = IPV6_MIN_MTU;
812                         df = 0;
813                 }
814 
815                 if (tunnel->parms.iph.daddr && skb_dst(skb))
816                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), NULL, skb, mtu);
817 
818                 if (skb->len > mtu) {
819                         icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
820                         ip_rt_put(rt);
821                         goto tx_error;
822                 }
823         }
824 
825         if (tunnel->err_count > 0) {
826                 if (time_before(jiffies,
827                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
828                         tunnel->err_count--;
829                         dst_link_failure(skb);
830                 } else
831                         tunnel->err_count = 0;
832         }
833 
834         /*
835          * Okay, now see if we can stuff it in the buffer as-is.
836          */
837         max_headroom = LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr);
838 
839         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
840             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
841                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
842                 if (!new_skb) {
843                         ip_rt_put(rt);
844                         dev->stats.tx_dropped++;
845                         dev_kfree_skb(skb);
846                         return NETDEV_TX_OK;
847                 }
848                 if (skb->sk)
849                         skb_set_owner_w(new_skb, skb->sk);
850                 dev_kfree_skb(skb);
851                 skb = new_skb;
852                 iph6 = ipv6_hdr(skb);
853         }
854 
855         skb->transport_header = skb->network_header;
856         skb_push(skb, sizeof(struct iphdr));
857         skb_reset_network_header(skb);
858         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
859         IPCB(skb)->flags = 0;
860         skb_dst_drop(skb);
861         skb_dst_set(skb, &rt->dst);
862 
863         /*
864          *      Push down and install the IPIP header.
865          */
866 
867         iph                     =       ip_hdr(skb);
868         iph->version            =       4;
869         iph->ihl                =       sizeof(struct iphdr)>>2;
870         iph->frag_off           =       df;
871         iph->protocol           =       IPPROTO_IPV6;
872         iph->tos                =       INET_ECN_encapsulate(tos, ipv6_get_dsfield(iph6));
873         iph->daddr              =       fl4.daddr;
874         iph->saddr              =       fl4.saddr;
875 
876         if ((iph->ttl = tiph->ttl) == 0)
877                 iph->ttl        =       iph6->hop_limit;
878 
879         iptunnel_xmit(skb, dev);
880         return NETDEV_TX_OK;
881 
882 tx_error_icmp:
883         dst_link_failure(skb);
884 tx_error:
885         dev->stats.tx_errors++;
886         dev_kfree_skb(skb);
887         return NETDEV_TX_OK;
888 }
889 
890 static void ipip6_tunnel_bind_dev(struct net_device *dev)
891 {
892         struct net_device *tdev = NULL;
893         struct ip_tunnel *tunnel;
894         const struct iphdr *iph;
895         struct flowi4 fl4;
896 
897         tunnel = netdev_priv(dev);
898         iph = &tunnel->parms.iph;
899 
900         if (iph->daddr) {
901                 struct rtable *rt = ip_route_output_ports(dev_net(dev), &fl4, NULL,
902                                                           iph->daddr, iph->saddr,
903                                                           0, 0,
904                                                           IPPROTO_IPV6,
905                                                           RT_TOS(iph->tos),
906                                                           tunnel->parms.link);
907 
908                 if (!IS_ERR(rt)) {
909                         tdev = rt->dst.dev;
910                         ip_rt_put(rt);
911                 }
912                 dev->flags |= IFF_POINTOPOINT;
913         }
914 
915         if (!tdev && tunnel->parms.link)
916                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
917 
918         if (tdev) {
919                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
920                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
921                 if (dev->mtu < IPV6_MIN_MTU)
922                         dev->mtu = IPV6_MIN_MTU;
923         }
924         dev->iflink = tunnel->parms.link;
925 }
926 
927 static void ipip6_tunnel_update(struct ip_tunnel *t, struct ip_tunnel_parm *p)
928 {
929         struct net *net = dev_net(t->dev);
930         struct sit_net *sitn = net_generic(net, sit_net_id);
931 
932         ipip6_tunnel_unlink(sitn, t);
933         synchronize_net();
934         t->parms.iph.saddr = p->iph.saddr;
935         t->parms.iph.daddr = p->iph.daddr;
936         memcpy(t->dev->dev_addr, &p->iph.saddr, 4);
937         memcpy(t->dev->broadcast, &p->iph.daddr, 4);
938         ipip6_tunnel_link(sitn, t);
939         t->parms.iph.ttl = p->iph.ttl;
940         t->parms.iph.tos = p->iph.tos;
941         if (t->parms.link != p->link) {
942                 t->parms.link = p->link;
943                 ipip6_tunnel_bind_dev(t->dev);
944         }
945         netdev_state_change(t->dev);
946 }
947 
948 #ifdef CONFIG_IPV6_SIT_6RD
949 static int ipip6_tunnel_update_6rd(struct ip_tunnel *t,
950                                    struct ip_tunnel_6rd *ip6rd)
951 {
952         struct in6_addr prefix;
953         __be32 relay_prefix;
954 
955         if (ip6rd->relay_prefixlen > 32 ||
956             ip6rd->prefixlen + (32 - ip6rd->relay_prefixlen) > 64)
957                 return -EINVAL;
958 
959         ipv6_addr_prefix(&prefix, &ip6rd->prefix, ip6rd->prefixlen);
960         if (!ipv6_addr_equal(&prefix, &ip6rd->prefix))
961                 return -EINVAL;
962         if (ip6rd->relay_prefixlen)
963                 relay_prefix = ip6rd->relay_prefix &
964                                htonl(0xffffffffUL <<
965                                      (32 - ip6rd->relay_prefixlen));
966         else
967                 relay_prefix = 0;
968         if (relay_prefix != ip6rd->relay_prefix)
969                 return -EINVAL;
970 
971         t->ip6rd.prefix = prefix;
972         t->ip6rd.relay_prefix = relay_prefix;
973         t->ip6rd.prefixlen = ip6rd->prefixlen;
974         t->ip6rd.relay_prefixlen = ip6rd->relay_prefixlen;
975         netdev_state_change(t->dev);
976         return 0;
977 }
978 #endif
979 
980 static int
981 ipip6_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
982 {
983         int err = 0;
984         struct ip_tunnel_parm p;
985         struct ip_tunnel_prl prl;
986         struct ip_tunnel *t;
987         struct net *net = dev_net(dev);
988         struct sit_net *sitn = net_generic(net, sit_net_id);
989 #ifdef CONFIG_IPV6_SIT_6RD
990         struct ip_tunnel_6rd ip6rd;
991 #endif
992 
993         switch (cmd) {
994         case SIOCGETTUNNEL:
995 #ifdef CONFIG_IPV6_SIT_6RD
996         case SIOCGET6RD:
997 #endif
998                 t = NULL;
999                 if (dev == sitn->fb_tunnel_dev) {
1000                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
1001                                 err = -EFAULT;
1002                                 break;
1003                         }
1004                         t = ipip6_tunnel_locate(net, &p, 0);
1005                 }
1006                 if (t == NULL)
1007                         t = netdev_priv(dev);
1008 
1009                 err = -EFAULT;
1010                 if (cmd == SIOCGETTUNNEL) {
1011                         memcpy(&p, &t->parms, sizeof(p));
1012                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &p,
1013                                          sizeof(p)))
1014                                 goto done;
1015 #ifdef CONFIG_IPV6_SIT_6RD
1016                 } else {
1017                         ip6rd.prefix = t->ip6rd.prefix;
1018                         ip6rd.relay_prefix = t->ip6rd.relay_prefix;
1019                         ip6rd.prefixlen = t->ip6rd.prefixlen;
1020                         ip6rd.relay_prefixlen = t->ip6rd.relay_prefixlen;
1021                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &ip6rd,
1022                                          sizeof(ip6rd)))
1023                                 goto done;
1024 #endif
1025                 }
1026                 err = 0;
1027                 break;
1028 
1029         case SIOCADDTUNNEL:
1030         case SIOCCHGTUNNEL:
1031                 err = -EPERM;
1032                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1033                         goto done;
1034 
1035                 err = -EFAULT;
1036                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1037                         goto done;
1038 
1039                 err = -EINVAL;
1040                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPV6 ||
1041                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
1042                         goto done;
1043                 if (p.iph.ttl)
1044                         p.iph.frag_off |= htons(IP_DF);
1045 
1046                 t = ipip6_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
1047 
1048                 if (dev != sitn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
1049                         if (t != NULL) {
1050                                 if (t->dev != dev) {
1051                                         err = -EEXIST;
1052                                         break;
1053                                 }
1054                         } else {
1055                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
1056                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
1057                                         err = -EINVAL;
1058                                         break;
1059                                 }
1060                                 t = netdev_priv(dev);
1061                         }
1062 
1063                         ipip6_tunnel_update(t, &p);
1064                 }
1065 
1066                 if (t) {
1067                         err = 0;
1068                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
1069                                 err = -EFAULT;
1070                 } else
1071                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
1072                 break;
1073 
1074         case SIOCDELTUNNEL:
1075                 err = -EPERM;
1076                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1077                         goto done;
1078 
1079                 if (dev == sitn->fb_tunnel_dev) {
1080                         err = -EFAULT;
1081                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
1082                                 goto done;
1083                         err = -ENOENT;
1084                         if ((t = ipip6_tunnel_locate(net, &p, 0)) == NULL)
1085                                 goto done;
1086                         err = -EPERM;
1087                         if (t == netdev_priv(sitn->fb_tunnel_dev))
1088                                 goto done;
1089                         dev = t->dev;
1090                 }
1091                 unregister_netdevice(dev);
1092                 err = 0;
1093                 break;
1094 
1095         case SIOCGETPRL:
1096                 err = -EINVAL;
1097                 if (dev == sitn->fb_tunnel_dev)
1098                         goto done;
1099                 err = -ENOENT;
1100                 if (!(t = netdev_priv(dev)))
1101                         goto done;
1102                 err = ipip6_tunnel_get_prl(t, ifr->ifr_ifru.ifru_data);
1103                 break;
1104 
1105         case SIOCADDPRL:
1106         case SIOCDELPRL:
1107         case SIOCCHGPRL:
1108                 err = -EPERM;
1109                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1110                         goto done;
1111                 err = -EINVAL;
1112                 if (dev == sitn->fb_tunnel_dev)
1113                         goto done;
1114                 err = -EFAULT;
1115                 if (copy_from_user(&prl, ifr->ifr_ifru.ifru_data, sizeof(prl)))
1116                         goto done;
1117                 err = -ENOENT;
1118                 if (!(t = netdev_priv(dev)))
1119                         goto done;
1120 
1121                 switch (cmd) {
1122                 case SIOCDELPRL:
1123                         err = ipip6_tunnel_del_prl(t, &prl);
1124                         break;
1125                 case SIOCADDPRL:
1126                 case SIOCCHGPRL:
1127                         err = ipip6_tunnel_add_prl(t, &prl, cmd == SIOCCHGPRL);
1128                         break;
1129                 }
1130                 netdev_state_change(dev);
1131                 break;
1132 
1133 #ifdef CONFIG_IPV6_SIT_6RD
1134         case SIOCADD6RD:
1135         case SIOCCHG6RD:
1136         case SIOCDEL6RD:
1137                 err = -EPERM;
1138                 if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
1139                         goto done;
1140 
1141                 err = -EFAULT;
1142                 if (copy_from_user(&ip6rd, ifr->ifr_ifru.ifru_data,
1143                                    sizeof(ip6rd)))
1144                         goto done;
1145 
1146                 t = netdev_priv(dev);
1147 
1148                 if (cmd != SIOCDEL6RD) {
1149                         err = ipip6_tunnel_update_6rd(t, &ip6rd);
1150                         if (err < 0)
1151                                 goto done;
1152                 } else
1153                         ipip6_tunnel_clone_6rd(dev, sitn);
1154 
1155                 err = 0;
1156                 break;
1157 #endif
1158 
1159         default:
1160                 err = -EINVAL;
1161         }
1162 
1163 done:
1164         return err;
1165 }
1166 
1167 static int ipip6_tunnel_change_mtu(struct net_device *dev, int new_mtu)
1168 {
1169         if (new_mtu < IPV6_MIN_MTU || new_mtu > 0xFFF8 - sizeof(struct iphdr))
1170                 return -EINVAL;
1171         dev->mtu = new_mtu;
1172         return 0;
1173 }
1174 
1175 static const struct net_device_ops ipip6_netdev_ops = {
1176         .ndo_uninit     = ipip6_tunnel_uninit,
1177         .ndo_start_xmit = ipip6_tunnel_xmit,
1178         .ndo_do_ioctl   = ipip6_tunnel_ioctl,
1179         .ndo_change_mtu = ipip6_tunnel_change_mtu,
1180         .ndo_get_stats64= ipip6_get_stats64,
1181 };
1182 
1183 static void ipip6_dev_free(struct net_device *dev)
1184 {
1185         free_percpu(dev->tstats);
1186         free_netdev(dev);
1187 }
1188 
1189 static void ipip6_tunnel_setup(struct net_device *dev)
1190 {
1191         dev->netdev_ops         = &ipip6_netdev_ops;
1192         dev->destructor         = ipip6_dev_free;
1193 
1194         dev->type               = ARPHRD_SIT;
1195         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
1196         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
1197         dev->flags              = IFF_NOARP;
1198         dev->priv_flags        &= ~IFF_XMIT_DST_RELEASE;
1199         dev->iflink             = 0;
1200         dev->addr_len           = 4;
1201         dev->features           |= NETIF_F_NETNS_LOCAL;
1202         dev->features           |= NETIF_F_LLTX;
1203 }
1204 
1205 static int ipip6_tunnel_init(struct net_device *dev)
1206 {
1207         struct ip_tunnel *tunnel = netdev_priv(dev);
1208 
1209         tunnel->dev = dev;
1210 
1211         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
1212         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
1213 
1214         ipip6_tunnel_bind_dev(dev);
1215         dev->tstats = alloc_percpu(struct pcpu_tstats);
1216         if (!dev->tstats)
1217                 return -ENOMEM;
1218 
1219         return 0;
1220 }
1221 
1222 static int __net_init ipip6_fb_tunnel_init(struct net_device *dev)
1223 {
1224         struct ip_tunnel *tunnel = netdev_priv(dev);
1225         struct iphdr *iph = &tunnel->parms.iph;
1226         struct net *net = dev_net(dev);
1227         struct sit_net *sitn = net_generic(net, sit_net_id);
1228 
1229         tunnel->dev = dev;
1230         strcpy(tunnel->parms.name, dev->name);
1231 
1232         iph->version            = 4;
1233         iph->protocol           = IPPROTO_IPV6;
1234         iph->ihl                = 5;
1235         iph->ttl                = 64;
1236 
1237         dev->tstats = alloc_percpu(struct pcpu_tstats);
1238         if (!dev->tstats)
1239                 return -ENOMEM;
1240         dev_hold(dev);
1241         rcu_assign_pointer(sitn->tunnels_wc[0], tunnel);
1242         return 0;
1243 }
1244 
1245 static void ipip6_netlink_parms(struct nlattr *data[],
1246                                 struct ip_tunnel_parm *parms)
1247 {
1248         memset(parms, 0, sizeof(*parms));
1249 
1250         parms->iph.version = 4;
1251         parms->iph.protocol = IPPROTO_IPV6;
1252         parms->iph.ihl = 5;
1253         parms->iph.ttl = 64;
1254 
1255         if (!data)
1256                 return;
1257 
1258         if (data[IFLA_IPTUN_LINK])
1259                 parms->link = nla_get_u32(data[IFLA_IPTUN_LINK]);
1260 
1261         if (data[IFLA_IPTUN_LOCAL])
1262                 parms->iph.saddr = nla_get_be32(data[IFLA_IPTUN_LOCAL]);
1263 
1264         if (data[IFLA_IPTUN_REMOTE])
1265                 parms->iph.daddr = nla_get_be32(data[IFLA_IPTUN_REMOTE]);
1266 
1267         if (data[IFLA_IPTUN_TTL]) {
1268                 parms->iph.ttl = nla_get_u8(data[IFLA_IPTUN_TTL]);
1269                 if (parms->iph.ttl)
1270                         parms->iph.frag_off = htons(IP_DF);
1271         }
1272 
1273         if (data[IFLA_IPTUN_TOS])
1274                 parms->iph.tos = nla_get_u8(data[IFLA_IPTUN_TOS]);
1275 
1276         if (!data[IFLA_IPTUN_PMTUDISC] || nla_get_u8(data[IFLA_IPTUN_PMTUDISC]))
1277                 parms->iph.frag_off = htons(IP_DF);
1278 
1279         if (data[IFLA_IPTUN_FLAGS])
1280                 parms->i_flags = nla_get_be16(data[IFLA_IPTUN_FLAGS]);
1281 }
1282 
1283 #ifdef CONFIG_IPV6_SIT_6RD
1284 /* This function returns true when 6RD attributes are present in the nl msg */
1285 static bool ipip6_netlink_6rd_parms(struct nlattr *data[],
1286                                     struct ip_tunnel_6rd *ip6rd)
1287 {
1288         bool ret = false;
1289         memset(ip6rd, 0, sizeof(*ip6rd));
1290 
1291         if (!data)
1292                 return ret;
1293 
1294         if (data[IFLA_IPTUN_6RD_PREFIX]) {
1295                 ret = true;
1296                 nla_memcpy(&ip6rd->prefix, data[IFLA_IPTUN_6RD_PREFIX],
1297                            sizeof(struct in6_addr));
1298         }
1299 
1300         if (data[IFLA_IPTUN_6RD_RELAY_PREFIX]) {
1301                 ret = true;
1302                 ip6rd->relay_prefix =
1303                         nla_get_be32(data[IFLA_IPTUN_6RD_RELAY_PREFIX]);
1304         }
1305 
1306         if (data[IFLA_IPTUN_6RD_PREFIXLEN]) {
1307                 ret = true;
1308                 ip6rd->prefixlen = nla_get_u16(data[IFLA_IPTUN_6RD_PREFIXLEN]);
1309         }
1310 
1311         if (data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]) {
1312                 ret = true;
1313                 ip6rd->relay_prefixlen =
1314                         nla_get_u16(data[IFLA_IPTUN_6RD_RELAY_PREFIXLEN]);
1315         }
1316 
1317         return ret;
1318 }
1319 #endif
1320 
1321 static int ipip6_newlink(struct net *src_net, struct net_device *dev,
1322                          struct nlattr *tb[], struct nlattr *data[])
1323 {
1324         struct net *net = dev_net(dev);
1325         struct ip_tunnel *nt;
1326 #ifdef CONFIG_IPV6_SIT_6RD
1327         struct ip_tunnel_6rd ip6rd;
1328 #endif
1329         int err;
1330 
1331         nt = netdev_priv(dev);
1332         ipip6_netlink_parms(data, &nt->parms);
1333 
1334         if (ipip6_tunnel_locate(net, &nt->parms, 0))
1335                 return -EEXIST;
1336 
1337         err = ipip6_tunnel_create(dev);
1338         if (err < 0)
1339                 return err;
1340 
1341 #ifdef CONFIG_IPV6_SIT_6RD
1342         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1343                 err = ipip6_tunnel_update_6rd(nt, &ip6rd);
1344 #endif
1345 
1346         return err;
1347 }
1348 
1349 static int ipip6_changelink(struct net_device *dev, struct nlattr *tb[],
1350                           struct nlattr *data[])
1351 {
1352         struct ip_tunnel *t;
1353         struct ip_tunnel_parm p;
1354         struct net *net = dev_net(dev);
1355         struct sit_net *sitn = net_generic(net, sit_net_id);
1356 #ifdef CONFIG_IPV6_SIT_6RD
1357         struct ip_tunnel_6rd ip6rd;
1358 #endif
1359 
1360         if (dev == sitn->fb_tunnel_dev)
1361                 return -EINVAL;
1362 
1363         ipip6_netlink_parms(data, &p);
1364 
1365         if (((dev->flags & IFF_POINTOPOINT) && !p.iph.daddr) ||
1366             (!(dev->flags & IFF_POINTOPOINT) && p.iph.daddr))
1367                 return -EINVAL;
1368 
1369         t = ipip6_tunnel_locate(net, &p, 0);
1370 
1371         if (t) {
1372                 if (t->dev != dev)
1373                         return -EEXIST;
1374         } else
1375                 t = netdev_priv(dev);
1376 
1377         ipip6_tunnel_update(t, &p);
1378 
1379 #ifdef CONFIG_IPV6_SIT_6RD
1380         if (ipip6_netlink_6rd_parms(data, &ip6rd))
1381                 return ipip6_tunnel_update_6rd(t, &ip6rd);
1382 #endif
1383 
1384         return 0;
1385 }
1386 
1387 static size_t ipip6_get_size(const struct net_device *dev)
1388 {
1389         return
1390                 /* IFLA_IPTUN_LINK */
1391                 nla_total_size(4) +
1392                 /* IFLA_IPTUN_LOCAL */
1393                 nla_total_size(4) +
1394                 /* IFLA_IPTUN_REMOTE */
1395                 nla_total_size(4) +
1396                 /* IFLA_IPTUN_TTL */
1397                 nla_total_size(1) +
1398                 /* IFLA_IPTUN_TOS */
1399                 nla_total_size(1) +
1400                 /* IFLA_IPTUN_PMTUDISC */
1401                 nla_total_size(1) +
1402                 /* IFLA_IPTUN_FLAGS */
1403                 nla_total_size(2) +
1404 #ifdef CONFIG_IPV6_SIT_6RD
1405                 /* IFLA_IPTUN_6RD_PREFIX */
1406                 nla_total_size(sizeof(struct in6_addr)) +
1407                 /* IFLA_IPTUN_6RD_RELAY_PREFIX */
1408                 nla_total_size(4) +
1409                 /* IFLA_IPTUN_6RD_PREFIXLEN */
1410                 nla_total_size(2) +
1411                 /* IFLA_IPTUN_6RD_RELAY_PREFIXLEN */
1412                 nla_total_size(2) +
1413 #endif
1414                 0;
1415 }
1416 
1417 static int ipip6_fill_info(struct sk_buff *skb, const struct net_device *dev)
1418 {
1419         struct ip_tunnel *tunnel = netdev_priv(dev);
1420         struct ip_tunnel_parm *parm = &tunnel->parms;
1421 
1422         if (nla_put_u32(skb, IFLA_IPTUN_LINK, parm->link) ||
1423             nla_put_be32(skb, IFLA_IPTUN_LOCAL, parm->iph.saddr) ||
1424             nla_put_be32(skb, IFLA_IPTUN_REMOTE, parm->iph.daddr) ||
1425             nla_put_u8(skb, IFLA_IPTUN_TTL, parm->iph.ttl) ||
1426             nla_put_u8(skb, IFLA_IPTUN_TOS, parm->iph.tos) ||
1427             nla_put_u8(skb, IFLA_IPTUN_PMTUDISC,
1428                        !!(parm->iph.frag_off & htons(IP_DF))) ||
1429             nla_put_be16(skb, IFLA_IPTUN_FLAGS, parm->i_flags))
1430                 goto nla_put_failure;
1431 
1432 #ifdef CONFIG_IPV6_SIT_6RD
1433         if (nla_put(skb, IFLA_IPTUN_6RD_PREFIX, sizeof(struct in6_addr),
1434                     &tunnel->ip6rd.prefix) ||
1435             nla_put_be32(skb, IFLA_IPTUN_6RD_RELAY_PREFIX,
1436                          tunnel->ip6rd.relay_prefix) ||
1437             nla_put_u16(skb, IFLA_IPTUN_6RD_PREFIXLEN,
1438                         tunnel->ip6rd.prefixlen) ||
1439             nla_put_u16(skb, IFLA_IPTUN_6RD_RELAY_PREFIXLEN,
1440                         tunnel->ip6rd.relay_prefixlen))
1441                 goto nla_put_failure;
1442 #endif
1443 
1444         return 0;
1445 
1446 nla_put_failure:
1447         return -EMSGSIZE;
1448 }
1449 
1450 static const struct nla_policy ipip6_policy[IFLA_IPTUN_MAX + 1] = {
1451         [IFLA_IPTUN_LINK]               = { .type = NLA_U32 },
1452         [IFLA_IPTUN_LOCAL]              = { .type = NLA_U32 },
1453         [IFLA_IPTUN_REMOTE]             = { .type = NLA_U32 },
1454         [IFLA_IPTUN_TTL]                = { .type = NLA_U8 },
1455         [IFLA_IPTUN_TOS]                = { .type = NLA_U8 },
1456         [IFLA_IPTUN_PMTUDISC]           = { .type = NLA_U8 },
1457         [IFLA_IPTUN_FLAGS]              = { .type = NLA_U16 },
1458 #ifdef CONFIG_IPV6_SIT_6RD
1459         [IFLA_IPTUN_6RD_PREFIX]         = { .len = sizeof(struct in6_addr) },
1460         [IFLA_IPTUN_6RD_RELAY_PREFIX]   = { .type = NLA_U32 },
1461         [IFLA_IPTUN_6RD_PREFIXLEN]      = { .type = NLA_U16 },
1462         [IFLA_IPTUN_6RD_RELAY_PREFIXLEN] = { .type = NLA_U16 },
1463 #endif
1464 };
1465 
1466 static struct rtnl_link_ops sit_link_ops __read_mostly = {
1467         .kind           = "sit",
1468         .maxtype        = IFLA_IPTUN_MAX,
1469         .policy         = ipip6_policy,
1470         .priv_size      = sizeof(struct ip_tunnel),
1471         .setup          = ipip6_tunnel_setup,
1472         .newlink        = ipip6_newlink,
1473         .changelink     = ipip6_changelink,
1474         .get_size       = ipip6_get_size,
1475         .fill_info      = ipip6_fill_info,
1476 };
1477 
1478 static struct xfrm_tunnel sit_handler __read_mostly = {
1479         .handler        =       ipip6_rcv,
1480         .err_handler    =       ipip6_err,
1481         .priority       =       1,
1482 };
1483 
1484 static void __net_exit sit_destroy_tunnels(struct sit_net *sitn, struct list_head *head)
1485 {
1486         int prio;
1487 
1488         for (prio = 1; prio < 4; prio++) {
1489                 int h;
1490                 for (h = 0; h < HASH_SIZE; h++) {
1491                         struct ip_tunnel *t;
1492 
1493                         t = rtnl_dereference(sitn->tunnels[prio][h]);
1494                         while (t != NULL) {
1495                                 unregister_netdevice_queue(t->dev, head);
1496                                 t = rtnl_dereference(t->next);
1497                         }
1498                 }
1499         }
1500 }
1501 
1502 static int __net_init sit_init_net(struct net *net)
1503 {
1504         struct sit_net *sitn = net_generic(net, sit_net_id);
1505         struct ip_tunnel *t;
1506         int err;
1507 
1508         sitn->tunnels[0] = sitn->tunnels_wc;
1509         sitn->tunnels[1] = sitn->tunnels_l;
1510         sitn->tunnels[2] = sitn->tunnels_r;
1511         sitn->tunnels[3] = sitn->tunnels_r_l;
1512 
1513         sitn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel), "sit0",
1514                                            ipip6_tunnel_setup);
1515         if (!sitn->fb_tunnel_dev) {
1516                 err = -ENOMEM;
1517                 goto err_alloc_dev;
1518         }
1519         dev_net_set(sitn->fb_tunnel_dev, net);
1520 
1521         err = ipip6_fb_tunnel_init(sitn->fb_tunnel_dev);
1522         if (err)
1523                 goto err_dev_free;
1524 
1525         ipip6_tunnel_clone_6rd(sitn->fb_tunnel_dev, sitn);
1526 
1527         if ((err = register_netdev(sitn->fb_tunnel_dev)))
1528                 goto err_reg_dev;
1529 
1530         t = netdev_priv(sitn->fb_tunnel_dev);
1531 
1532         strcpy(t->parms.name, sitn->fb_tunnel_dev->name);
1533         return 0;
1534 
1535 err_reg_dev:
1536         dev_put(sitn->fb_tunnel_dev);
1537 err_dev_free:
1538         ipip6_dev_free(sitn->fb_tunnel_dev);
1539 err_alloc_dev:
1540         return err;
1541 }
1542 
1543 static void __net_exit sit_exit_net(struct net *net)
1544 {
1545         struct sit_net *sitn = net_generic(net, sit_net_id);
1546         LIST_HEAD(list);
1547 
1548         rtnl_lock();
1549         sit_destroy_tunnels(sitn, &list);
1550         unregister_netdevice_queue(sitn->fb_tunnel_dev, &list);
1551         unregister_netdevice_many(&list);
1552         rtnl_unlock();
1553 }
1554 
1555 static struct pernet_operations sit_net_ops = {
1556         .init = sit_init_net,
1557         .exit = sit_exit_net,
1558         .id   = &sit_net_id,
1559         .size = sizeof(struct sit_net),
1560 };
1561 
1562 static void __exit sit_cleanup(void)
1563 {
1564         rtnl_link_unregister(&sit_link_ops);
1565         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1566 
1567         unregister_pernet_device(&sit_net_ops);
1568         rcu_barrier(); /* Wait for completion of call_rcu()'s */
1569 }
1570 
1571 static int __init sit_init(void)
1572 {
1573         int err;
1574 
1575         pr_info("IPv6 over IPv4 tunneling driver\n");
1576 
1577         err = register_pernet_device(&sit_net_ops);
1578         if (err < 0)
1579                 return err;
1580         err = xfrm4_tunnel_register(&sit_handler, AF_INET6);
1581         if (err < 0) {
1582                 pr_info("%s: can't add protocol\n", __func__);
1583                 goto xfrm_tunnel_failed;
1584         }
1585         err = rtnl_link_register(&sit_link_ops);
1586         if (err < 0)
1587                 goto rtnl_link_failed;
1588 
1589 out:
1590         return err;
1591 
1592 rtnl_link_failed:
1593         xfrm4_tunnel_deregister(&sit_handler, AF_INET6);
1594 xfrm_tunnel_failed:
1595         unregister_pernet_device(&sit_net_ops);
1596         goto out;
1597 }
1598 
1599 module_init(sit_init);
1600 module_exit(sit_cleanup);
1601 MODULE_LICENSE("GPL");
1602 MODULE_ALIAS_NETDEV("sit0");
1603 

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