ec036731a70ba0774164de8574c30d0f0e1baa64
[linux-2.6.git] / net / ipv4 / ipip.c
1 /*
2  *      Linux NET3:     IP/IP protocol decoder.
3  *
4  *      Authors:
5  *              Sam Lantinga (slouken@cs.ucdavis.edu)  02/01/95
6  *
7  *      Fixes:
8  *              Alan Cox        :       Merged and made usable non modular (its so tiny its silly as
9  *                                      a module taking up 2 pages).
10  *              Alan Cox        :       Fixed bug with 1.3.18 and IPIP not working (now needs to set skb->h.iph)
11  *                                      to keep ip_forward happy.
12  *              Alan Cox        :       More fixes for 1.3.21, and firewall fix. Maybe this will work soon 8).
13  *              Kai Schulte     :       Fixed #defines for IP_FIREWALL->FIREWALL
14  *              David Woodhouse :       Perform some basic ICMP handling.
15  *                                      IPIP Routing without decapsulation.
16  *              Carlos Picoto   :       GRE over IP support
17  *              Alexey Kuznetsov:       Reworked. Really, now it is truncated version of ipv4/ip_gre.c.
18  *                                      I do not want to merge them together.
19  *
20  *      This program is free software; you can redistribute it and/or
21  *      modify it under the terms of the GNU General Public License
22  *      as published by the Free Software Foundation; either version
23  *      2 of the License, or (at your option) any later version.
24  *
25  */
26
27 /* tunnel.c: an IP tunnel driver
28
29         The purpose of this driver is to provide an IP tunnel through
30         which you can tunnel network traffic transparently across subnets.
31
32         This was written by looking at Nick Holloway's dummy driver
33         Thanks for the great code!
34
35                 -Sam Lantinga   (slouken@cs.ucdavis.edu)  02/01/95
36
37         Minor tweaks:
38                 Cleaned up the code a little and added some pre-1.3.0 tweaks.
39                 dev->hard_header/hard_header_len changed to use no headers.
40                 Comments/bracketing tweaked.
41                 Made the tunnels use dev->name not tunnel: when error reporting.
42                 Added tx_dropped stat
43
44                 -Alan Cox       (alan@lxorguk.ukuu.org.uk) 21 March 95
45
46         Reworked:
47                 Changed to tunnel to destination gateway in addition to the
48                         tunnel's pointopoint address
49                 Almost completely rewritten
50                 Note:  There is currently no firewall or ICMP handling done.
51
52                 -Sam Lantinga   (slouken@cs.ucdavis.edu) 02/13/96
53
54 */
55
56 /* Things I wish I had known when writing the tunnel driver:
57
58         When the tunnel_xmit() function is called, the skb contains the
59         packet to be sent (plus a great deal of extra info), and dev
60         contains the tunnel device that _we_ are.
61
62         When we are passed a packet, we are expected to fill in the
63         source address with our source IP address.
64
65         What is the proper way to allocate, copy and free a buffer?
66         After you allocate it, it is a "0 length" chunk of memory
67         starting at zero.  If you want to add headers to the buffer
68         later, you'll have to call "skb_reserve(skb, amount)" with
69         the amount of memory you want reserved.  Then, you call
70         "skb_put(skb, amount)" with the amount of space you want in
71         the buffer.  skb_put() returns a pointer to the top (#0) of
72         that buffer.  skb->len is set to the amount of space you have
73         "allocated" with skb_put().  You can then write up to skb->len
74         bytes to that buffer.  If you need more, you can call skb_put()
75         again with the additional amount of space you need.  You can
76         find out how much more space you can allocate by calling
77         "skb_tailroom(skb)".
78         Now, to add header space, call "skb_push(skb, header_len)".
79         This creates space at the beginning of the buffer and returns
80         a pointer to this new space.  If later you need to strip a
81         header from a buffer, call "skb_pull(skb, header_len)".
82         skb_headroom() will return how much space is left at the top
83         of the buffer (before the main data).  Remember, this headroom
84         space must be reserved before the skb_put() function is called.
85         */
86
87 /*
88    This version of net/ipv4/ipip.c is cloned of net/ipv4/ip_gre.c
89
90    For comments look at net/ipv4/ip_gre.c --ANK
91  */
92
93
94 #include <linux/capability.h>
95 #include <linux/module.h>
96 #include <linux/types.h>
97 #include <linux/kernel.h>
98 #include <linux/slab.h>
99 #include <asm/uaccess.h>
100 #include <linux/skbuff.h>
101 #include <linux/netdevice.h>
102 #include <linux/in.h>
103 #include <linux/tcp.h>
104 #include <linux/udp.h>
105 #include <linux/if_arp.h>
106 #include <linux/mroute.h>
107 #include <linux/init.h>
108 #include <linux/netfilter_ipv4.h>
109 #include <linux/if_ether.h>
110
111 #include <net/sock.h>
112 #include <net/ip.h>
113 #include <net/icmp.h>
114 #include <net/ipip.h>
115 #include <net/inet_ecn.h>
116 #include <net/xfrm.h>
117 #include <net/net_namespace.h>
118 #include <net/netns/generic.h>
119
120 #define HASH_SIZE  16
121 #define HASH(addr) (((__force u32)addr^((__force u32)addr>>4))&0xF)
122
123 static int ipip_net_id __read_mostly;
124 struct ipip_net {
125         struct ip_tunnel *tunnels_r_l[HASH_SIZE];
126         struct ip_tunnel *tunnels_r[HASH_SIZE];
127         struct ip_tunnel *tunnels_l[HASH_SIZE];
128         struct ip_tunnel *tunnels_wc[1];
129         struct ip_tunnel **tunnels[4];
130
131         struct net_device *fb_tunnel_dev;
132 };
133
134 static void ipip_tunnel_init(struct net_device *dev);
135 static void ipip_tunnel_setup(struct net_device *dev);
136
137 /*
138  * Locking : hash tables are protected by RCU and a spinlock
139  */
140 static DEFINE_SPINLOCK(ipip_lock);
141
142 #define for_each_ip_tunnel_rcu(start) \
143         for (t = rcu_dereference(start); t; t = rcu_dereference(t->next))
144
145 static struct ip_tunnel * ipip_tunnel_lookup(struct net *net,
146                 __be32 remote, __be32 local)
147 {
148         unsigned h0 = HASH(remote);
149         unsigned h1 = HASH(local);
150         struct ip_tunnel *t;
151         struct ipip_net *ipn = net_generic(net, ipip_net_id);
152
153         for_each_ip_tunnel_rcu(ipn->tunnels_r_l[h0 ^ h1])
154                 if (local == t->parms.iph.saddr &&
155                     remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
156                         return t;
157
158         for_each_ip_tunnel_rcu(ipn->tunnels_r[h0])
159                 if (remote == t->parms.iph.daddr && (t->dev->flags&IFF_UP))
160                         return t;
161
162         for_each_ip_tunnel_rcu(ipn->tunnels_l[h1])
163                 if (local == t->parms.iph.saddr && (t->dev->flags&IFF_UP))
164                         return t;
165
166         t = rcu_dereference(ipn->tunnels_wc[0]);
167         if (t && (t->dev->flags&IFF_UP))
168                 return t;
169         return NULL;
170 }
171
172 static struct ip_tunnel **__ipip_bucket(struct ipip_net *ipn,
173                 struct ip_tunnel_parm *parms)
174 {
175         __be32 remote = parms->iph.daddr;
176         __be32 local = parms->iph.saddr;
177         unsigned h = 0;
178         int prio = 0;
179
180         if (remote) {
181                 prio |= 2;
182                 h ^= HASH(remote);
183         }
184         if (local) {
185                 prio |= 1;
186                 h ^= HASH(local);
187         }
188         return &ipn->tunnels[prio][h];
189 }
190
191 static inline struct ip_tunnel **ipip_bucket(struct ipip_net *ipn,
192                 struct ip_tunnel *t)
193 {
194         return __ipip_bucket(ipn, &t->parms);
195 }
196
197 static void ipip_tunnel_unlink(struct ipip_net *ipn, struct ip_tunnel *t)
198 {
199         struct ip_tunnel **tp;
200
201         for (tp = ipip_bucket(ipn, t); *tp; tp = &(*tp)->next) {
202                 if (t == *tp) {
203                         spin_lock_bh(&ipip_lock);
204                         *tp = t->next;
205                         spin_unlock_bh(&ipip_lock);
206                         break;
207                 }
208         }
209 }
210
211 static void ipip_tunnel_link(struct ipip_net *ipn, struct ip_tunnel *t)
212 {
213         struct ip_tunnel **tp = ipip_bucket(ipn, t);
214
215         spin_lock_bh(&ipip_lock);
216         t->next = *tp;
217         rcu_assign_pointer(*tp, t);
218         spin_unlock_bh(&ipip_lock);
219 }
220
221 static struct ip_tunnel * ipip_tunnel_locate(struct net *net,
222                 struct ip_tunnel_parm *parms, int create)
223 {
224         __be32 remote = parms->iph.daddr;
225         __be32 local = parms->iph.saddr;
226         struct ip_tunnel *t, **tp, *nt;
227         struct net_device *dev;
228         char name[IFNAMSIZ];
229         struct ipip_net *ipn = net_generic(net, ipip_net_id);
230
231         for (tp = __ipip_bucket(ipn, parms); (t = *tp) != NULL; tp = &t->next) {
232                 if (local == t->parms.iph.saddr && remote == t->parms.iph.daddr)
233                         return t;
234         }
235         if (!create)
236                 return NULL;
237
238         if (parms->name[0])
239                 strlcpy(name, parms->name, IFNAMSIZ);
240         else
241                 sprintf(name, "tunl%%d");
242
243         dev = alloc_netdev(sizeof(*t), name, ipip_tunnel_setup);
244         if (dev == NULL)
245                 return NULL;
246
247         dev_net_set(dev, net);
248
249         if (strchr(name, '%')) {
250                 if (dev_alloc_name(dev, name) < 0)
251                         goto failed_free;
252         }
253
254         nt = netdev_priv(dev);
255         nt->parms = *parms;
256
257         ipip_tunnel_init(dev);
258
259         if (register_netdevice(dev) < 0)
260                 goto failed_free;
261
262         dev_hold(dev);
263         ipip_tunnel_link(ipn, nt);
264         return nt;
265
266 failed_free:
267         free_netdev(dev);
268         return NULL;
269 }
270
271 static void ipip_tunnel_uninit(struct net_device *dev)
272 {
273         struct net *net = dev_net(dev);
274         struct ipip_net *ipn = net_generic(net, ipip_net_id);
275
276         if (dev == ipn->fb_tunnel_dev) {
277                 spin_lock_bh(&ipip_lock);
278                 ipn->tunnels_wc[0] = NULL;
279                 spin_unlock_bh(&ipip_lock);
280         } else
281                 ipip_tunnel_unlink(ipn, netdev_priv(dev));
282         dev_put(dev);
283 }
284
285 static int ipip_err(struct sk_buff *skb, u32 info)
286 {
287
288 /* All the routers (except for Linux) return only
289    8 bytes of packet payload. It means, that precise relaying of
290    ICMP in the real Internet is absolutely infeasible.
291  */
292         struct iphdr *iph = (struct iphdr *)skb->data;
293         const int type = icmp_hdr(skb)->type;
294         const int code = icmp_hdr(skb)->code;
295         struct ip_tunnel *t;
296         int err;
297
298         switch (type) {
299         default:
300         case ICMP_PARAMETERPROB:
301                 return 0;
302
303         case ICMP_DEST_UNREACH:
304                 switch (code) {
305                 case ICMP_SR_FAILED:
306                 case ICMP_PORT_UNREACH:
307                         /* Impossible event. */
308                         return 0;
309                 case ICMP_FRAG_NEEDED:
310                         /* Soft state for pmtu is maintained by IP core. */
311                         return 0;
312                 default:
313                         /* All others are translated to HOST_UNREACH.
314                            rfc2003 contains "deep thoughts" about NET_UNREACH,
315                            I believe they are just ether pollution. --ANK
316                          */
317                         break;
318                 }
319                 break;
320         case ICMP_TIME_EXCEEDED:
321                 if (code != ICMP_EXC_TTL)
322                         return 0;
323                 break;
324         }
325
326         err = -ENOENT;
327
328         rcu_read_lock();
329         t = ipip_tunnel_lookup(dev_net(skb->dev), iph->daddr, iph->saddr);
330         if (t == NULL || t->parms.iph.daddr == 0)
331                 goto out;
332
333         err = 0;
334         if (t->parms.iph.ttl == 0 && type == ICMP_TIME_EXCEEDED)
335                 goto out;
336
337         if (time_before(jiffies, t->err_time + IPTUNNEL_ERR_TIMEO))
338                 t->err_count++;
339         else
340                 t->err_count = 1;
341         t->err_time = jiffies;
342 out:
343         rcu_read_unlock();
344         return err;
345 }
346
347 static inline void ipip_ecn_decapsulate(const struct iphdr *outer_iph,
348                                         struct sk_buff *skb)
349 {
350         struct iphdr *inner_iph = ip_hdr(skb);
351
352         if (INET_ECN_is_ce(outer_iph->tos))
353                 IP_ECN_set_ce(inner_iph);
354 }
355
356 static int ipip_rcv(struct sk_buff *skb)
357 {
358         struct ip_tunnel *tunnel;
359         const struct iphdr *iph = ip_hdr(skb);
360
361         rcu_read_lock();
362         if ((tunnel = ipip_tunnel_lookup(dev_net(skb->dev),
363                                         iph->saddr, iph->daddr)) != NULL) {
364                 if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb)) {
365                         rcu_read_unlock();
366                         kfree_skb(skb);
367                         return 0;
368                 }
369
370                 secpath_reset(skb);
371
372                 skb->mac_header = skb->network_header;
373                 skb_reset_network_header(skb);
374                 skb->protocol = htons(ETH_P_IP);
375                 skb->pkt_type = PACKET_HOST;
376
377                 skb_tunnel_rx(skb, tunnel->dev);
378
379                 ipip_ecn_decapsulate(iph, skb);
380                 netif_rx(skb);
381                 rcu_read_unlock();
382                 return 0;
383         }
384         rcu_read_unlock();
385
386         return -1;
387 }
388
389 /*
390  *      This function assumes it is being called from dev_queue_xmit()
391  *      and that skb is filled properly by that function.
392  */
393
394 static netdev_tx_t ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
395 {
396         struct ip_tunnel *tunnel = netdev_priv(dev);
397         struct net_device_stats *stats = &dev->stats;
398         struct netdev_queue *txq = netdev_get_tx_queue(dev, 0);
399         struct iphdr  *tiph = &tunnel->parms.iph;
400         u8     tos = tunnel->parms.iph.tos;
401         __be16 df = tiph->frag_off;
402         struct rtable *rt;                      /* Route to the other host */
403         struct net_device *tdev;                        /* Device to other host */
404         struct iphdr  *old_iph = ip_hdr(skb);
405         struct iphdr  *iph;                     /* Our new IP header */
406         unsigned int max_headroom;              /* The extra header space needed */
407         __be32 dst = tiph->daddr;
408         int    mtu;
409
410         if (skb->protocol != htons(ETH_P_IP))
411                 goto tx_error;
412
413         if (tos&1)
414                 tos = old_iph->tos;
415
416         if (!dst) {
417                 /* NBMA tunnel */
418                 if ((rt = skb_rtable(skb)) == NULL) {
419                         stats->tx_fifo_errors++;
420                         goto tx_error;
421                 }
422                 if ((dst = rt->rt_gateway) == 0)
423                         goto tx_error_icmp;
424         }
425
426         {
427                 struct flowi fl = { .oif = tunnel->parms.link,
428                                     .nl_u = { .ip4_u =
429                                               { .daddr = dst,
430                                                 .saddr = tiph->saddr,
431                                                 .tos = RT_TOS(tos) } },
432                                     .proto = IPPROTO_IPIP };
433                 if (ip_route_output_key(dev_net(dev), &rt, &fl)) {
434                         stats->tx_carrier_errors++;
435                         goto tx_error_icmp;
436                 }
437         }
438         tdev = rt->dst.dev;
439
440         if (tdev == dev) {
441                 ip_rt_put(rt);
442                 stats->collisions++;
443                 goto tx_error;
444         }
445
446         df |= old_iph->frag_off & htons(IP_DF);
447
448         if (df) {
449                 mtu = dst_mtu(&rt->dst) - sizeof(struct iphdr);
450
451                 if (mtu < 68) {
452                         stats->collisions++;
453                         ip_rt_put(rt);
454                         goto tx_error;
455                 }
456
457                 if (skb_dst(skb))
458                         skb_dst(skb)->ops->update_pmtu(skb_dst(skb), mtu);
459
460                 if ((old_iph->frag_off & htons(IP_DF)) &&
461                     mtu < ntohs(old_iph->tot_len)) {
462                         icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
463                                   htonl(mtu));
464                         ip_rt_put(rt);
465                         goto tx_error;
466                 }
467         }
468
469         if (tunnel->err_count > 0) {
470                 if (time_before(jiffies,
471                                 tunnel->err_time + IPTUNNEL_ERR_TIMEO)) {
472                         tunnel->err_count--;
473                         dst_link_failure(skb);
474                 } else
475                         tunnel->err_count = 0;
476         }
477
478         /*
479          * Okay, now see if we can stuff it in the buffer as-is.
480          */
481         max_headroom = (LL_RESERVED_SPACE(tdev)+sizeof(struct iphdr));
482
483         if (skb_headroom(skb) < max_headroom || skb_shared(skb) ||
484             (skb_cloned(skb) && !skb_clone_writable(skb, 0))) {
485                 struct sk_buff *new_skb = skb_realloc_headroom(skb, max_headroom);
486                 if (!new_skb) {
487                         ip_rt_put(rt);
488                         txq->tx_dropped++;
489                         dev_kfree_skb(skb);
490                         return NETDEV_TX_OK;
491                 }
492                 if (skb->sk)
493                         skb_set_owner_w(new_skb, skb->sk);
494                 dev_kfree_skb(skb);
495                 skb = new_skb;
496                 old_iph = ip_hdr(skb);
497         }
498
499         skb->transport_header = skb->network_header;
500         skb_push(skb, sizeof(struct iphdr));
501         skb_reset_network_header(skb);
502         memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
503         IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
504                               IPSKB_REROUTED);
505         skb_dst_drop(skb);
506         skb_dst_set(skb, &rt->dst);
507
508         /*
509          *      Push down and install the IPIP header.
510          */
511
512         iph                     =       ip_hdr(skb);
513         iph->version            =       4;
514         iph->ihl                =       sizeof(struct iphdr)>>2;
515         iph->frag_off           =       df;
516         iph->protocol           =       IPPROTO_IPIP;
517         iph->tos                =       INET_ECN_encapsulate(tos, old_iph->tos);
518         iph->daddr              =       rt->rt_dst;
519         iph->saddr              =       rt->rt_src;
520
521         if ((iph->ttl = tiph->ttl) == 0)
522                 iph->ttl        =       old_iph->ttl;
523
524         nf_reset(skb);
525
526         IPTUNNEL_XMIT();
527         return NETDEV_TX_OK;
528
529 tx_error_icmp:
530         dst_link_failure(skb);
531 tx_error:
532         stats->tx_errors++;
533         dev_kfree_skb(skb);
534         return NETDEV_TX_OK;
535 }
536
537 static void ipip_tunnel_bind_dev(struct net_device *dev)
538 {
539         struct net_device *tdev = NULL;
540         struct ip_tunnel *tunnel;
541         struct iphdr *iph;
542
543         tunnel = netdev_priv(dev);
544         iph = &tunnel->parms.iph;
545
546         if (iph->daddr) {
547                 struct flowi fl = { .oif = tunnel->parms.link,
548                                     .nl_u = { .ip4_u =
549                                               { .daddr = iph->daddr,
550                                                 .saddr = iph->saddr,
551                                                 .tos = RT_TOS(iph->tos) } },
552                                     .proto = IPPROTO_IPIP };
553                 struct rtable *rt;
554                 if (!ip_route_output_key(dev_net(dev), &rt, &fl)) {
555                         tdev = rt->dst.dev;
556                         ip_rt_put(rt);
557                 }
558                 dev->flags |= IFF_POINTOPOINT;
559         }
560
561         if (!tdev && tunnel->parms.link)
562                 tdev = __dev_get_by_index(dev_net(dev), tunnel->parms.link);
563
564         if (tdev) {
565                 dev->hard_header_len = tdev->hard_header_len + sizeof(struct iphdr);
566                 dev->mtu = tdev->mtu - sizeof(struct iphdr);
567         }
568         dev->iflink = tunnel->parms.link;
569 }
570
571 static int
572 ipip_tunnel_ioctl (struct net_device *dev, struct ifreq *ifr, int cmd)
573 {
574         int err = 0;
575         struct ip_tunnel_parm p;
576         struct ip_tunnel *t;
577         struct net *net = dev_net(dev);
578         struct ipip_net *ipn = net_generic(net, ipip_net_id);
579
580         switch (cmd) {
581         case SIOCGETTUNNEL:
582                 t = NULL;
583                 if (dev == ipn->fb_tunnel_dev) {
584                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p))) {
585                                 err = -EFAULT;
586                                 break;
587                         }
588                         t = ipip_tunnel_locate(net, &p, 0);
589                 }
590                 if (t == NULL)
591                         t = netdev_priv(dev);
592                 memcpy(&p, &t->parms, sizeof(p));
593                 if (copy_to_user(ifr->ifr_ifru.ifru_data, &p, sizeof(p)))
594                         err = -EFAULT;
595                 break;
596
597         case SIOCADDTUNNEL:
598         case SIOCCHGTUNNEL:
599                 err = -EPERM;
600                 if (!capable(CAP_NET_ADMIN))
601                         goto done;
602
603                 err = -EFAULT;
604                 if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
605                         goto done;
606
607                 err = -EINVAL;
608                 if (p.iph.version != 4 || p.iph.protocol != IPPROTO_IPIP ||
609                     p.iph.ihl != 5 || (p.iph.frag_off&htons(~IP_DF)))
610                         goto done;
611                 if (p.iph.ttl)
612                         p.iph.frag_off |= htons(IP_DF);
613
614                 t = ipip_tunnel_locate(net, &p, cmd == SIOCADDTUNNEL);
615
616                 if (dev != ipn->fb_tunnel_dev && cmd == SIOCCHGTUNNEL) {
617                         if (t != NULL) {
618                                 if (t->dev != dev) {
619                                         err = -EEXIST;
620                                         break;
621                                 }
622                         } else {
623                                 if (((dev->flags&IFF_POINTOPOINT) && !p.iph.daddr) ||
624                                     (!(dev->flags&IFF_POINTOPOINT) && p.iph.daddr)) {
625                                         err = -EINVAL;
626                                         break;
627                                 }
628                                 t = netdev_priv(dev);
629                                 ipip_tunnel_unlink(ipn, t);
630                                 t->parms.iph.saddr = p.iph.saddr;
631                                 t->parms.iph.daddr = p.iph.daddr;
632                                 memcpy(dev->dev_addr, &p.iph.saddr, 4);
633                                 memcpy(dev->broadcast, &p.iph.daddr, 4);
634                                 ipip_tunnel_link(ipn, t);
635                                 netdev_state_change(dev);
636                         }
637                 }
638
639                 if (t) {
640                         err = 0;
641                         if (cmd == SIOCCHGTUNNEL) {
642                                 t->parms.iph.ttl = p.iph.ttl;
643                                 t->parms.iph.tos = p.iph.tos;
644                                 t->parms.iph.frag_off = p.iph.frag_off;
645                                 if (t->parms.link != p.link) {
646                                         t->parms.link = p.link;
647                                         ipip_tunnel_bind_dev(dev);
648                                         netdev_state_change(dev);
649                                 }
650                         }
651                         if (copy_to_user(ifr->ifr_ifru.ifru_data, &t->parms, sizeof(p)))
652                                 err = -EFAULT;
653                 } else
654                         err = (cmd == SIOCADDTUNNEL ? -ENOBUFS : -ENOENT);
655                 break;
656
657         case SIOCDELTUNNEL:
658                 err = -EPERM;
659                 if (!capable(CAP_NET_ADMIN))
660                         goto done;
661
662                 if (dev == ipn->fb_tunnel_dev) {
663                         err = -EFAULT;
664                         if (copy_from_user(&p, ifr->ifr_ifru.ifru_data, sizeof(p)))
665                                 goto done;
666                         err = -ENOENT;
667                         if ((t = ipip_tunnel_locate(net, &p, 0)) == NULL)
668                                 goto done;
669                         err = -EPERM;
670                         if (t->dev == ipn->fb_tunnel_dev)
671                                 goto done;
672                         dev = t->dev;
673                 }
674                 unregister_netdevice(dev);
675                 err = 0;
676                 break;
677
678         default:
679                 err = -EINVAL;
680         }
681
682 done:
683         return err;
684 }
685
686 static int ipip_tunnel_change_mtu(struct net_device *dev, int new_mtu)
687 {
688         if (new_mtu < 68 || new_mtu > 0xFFF8 - sizeof(struct iphdr))
689                 return -EINVAL;
690         dev->mtu = new_mtu;
691         return 0;
692 }
693
694 static const struct net_device_ops ipip_netdev_ops = {
695         .ndo_uninit     = ipip_tunnel_uninit,
696         .ndo_start_xmit = ipip_tunnel_xmit,
697         .ndo_do_ioctl   = ipip_tunnel_ioctl,
698         .ndo_change_mtu = ipip_tunnel_change_mtu,
699
700 };
701
702 static void ipip_tunnel_setup(struct net_device *dev)
703 {
704         dev->netdev_ops         = &ipip_netdev_ops;
705         dev->destructor         = free_netdev;
706
707         dev->type               = ARPHRD_TUNNEL;
708         dev->hard_header_len    = LL_MAX_HEADER + sizeof(struct iphdr);
709         dev->mtu                = ETH_DATA_LEN - sizeof(struct iphdr);
710         dev->flags              = IFF_NOARP;
711         dev->iflink             = 0;
712         dev->addr_len           = 4;
713         dev->features           |= NETIF_F_NETNS_LOCAL;
714         dev->priv_flags         &= ~IFF_XMIT_DST_RELEASE;
715 }
716
717 static void ipip_tunnel_init(struct net_device *dev)
718 {
719         struct ip_tunnel *tunnel = netdev_priv(dev);
720
721         tunnel->dev = dev;
722         strcpy(tunnel->parms.name, dev->name);
723
724         memcpy(dev->dev_addr, &tunnel->parms.iph.saddr, 4);
725         memcpy(dev->broadcast, &tunnel->parms.iph.daddr, 4);
726
727         ipip_tunnel_bind_dev(dev);
728 }
729
730 static void __net_init ipip_fb_tunnel_init(struct net_device *dev)
731 {
732         struct ip_tunnel *tunnel = netdev_priv(dev);
733         struct iphdr *iph = &tunnel->parms.iph;
734         struct ipip_net *ipn = net_generic(dev_net(dev), ipip_net_id);
735
736         tunnel->dev = dev;
737         strcpy(tunnel->parms.name, dev->name);
738
739         iph->version            = 4;
740         iph->protocol           = IPPROTO_IPIP;
741         iph->ihl                = 5;
742
743         dev_hold(dev);
744         ipn->tunnels_wc[0]      = tunnel;
745 }
746
747 static struct xfrm_tunnel ipip_handler = {
748         .handler        =       ipip_rcv,
749         .err_handler    =       ipip_err,
750         .priority       =       1,
751 };
752
753 static const char banner[] __initconst =
754         KERN_INFO "IPv4 over IPv4 tunneling driver\n";
755
756 static void ipip_destroy_tunnels(struct ipip_net *ipn, struct list_head *head)
757 {
758         int prio;
759
760         for (prio = 1; prio < 4; prio++) {
761                 int h;
762                 for (h = 0; h < HASH_SIZE; h++) {
763                         struct ip_tunnel *t = ipn->tunnels[prio][h];
764
765                         while (t != NULL) {
766                                 unregister_netdevice_queue(t->dev, head);
767                                 t = t->next;
768                         }
769                 }
770         }
771 }
772
773 static int __net_init ipip_init_net(struct net *net)
774 {
775         struct ipip_net *ipn = net_generic(net, ipip_net_id);
776         int err;
777
778         ipn->tunnels[0] = ipn->tunnels_wc;
779         ipn->tunnels[1] = ipn->tunnels_l;
780         ipn->tunnels[2] = ipn->tunnels_r;
781         ipn->tunnels[3] = ipn->tunnels_r_l;
782
783         ipn->fb_tunnel_dev = alloc_netdev(sizeof(struct ip_tunnel),
784                                            "tunl0",
785                                            ipip_tunnel_setup);
786         if (!ipn->fb_tunnel_dev) {
787                 err = -ENOMEM;
788                 goto err_alloc_dev;
789         }
790         dev_net_set(ipn->fb_tunnel_dev, net);
791
792         ipip_fb_tunnel_init(ipn->fb_tunnel_dev);
793
794         if ((err = register_netdev(ipn->fb_tunnel_dev)))
795                 goto err_reg_dev;
796
797         return 0;
798
799 err_reg_dev:
800         free_netdev(ipn->fb_tunnel_dev);
801 err_alloc_dev:
802         /* nothing */
803         return err;
804 }
805
806 static void __net_exit ipip_exit_net(struct net *net)
807 {
808         struct ipip_net *ipn = net_generic(net, ipip_net_id);
809         LIST_HEAD(list);
810
811         rtnl_lock();
812         ipip_destroy_tunnels(ipn, &list);
813         unregister_netdevice_queue(ipn->fb_tunnel_dev, &list);
814         unregister_netdevice_many(&list);
815         rtnl_unlock();
816 }
817
818 static struct pernet_operations ipip_net_ops = {
819         .init = ipip_init_net,
820         .exit = ipip_exit_net,
821         .id   = &ipip_net_id,
822         .size = sizeof(struct ipip_net),
823 };
824
825 static int __init ipip_init(void)
826 {
827         int err;
828
829         printk(banner);
830
831         err = register_pernet_device(&ipip_net_ops);
832         if (err < 0)
833                 return err;
834         err = xfrm4_tunnel_register(&ipip_handler, AF_INET);
835         if (err < 0) {
836                 unregister_pernet_device(&ipip_net_ops);
837                 printk(KERN_INFO "ipip init: can't register tunnel\n");
838         }
839         return err;
840 }
841
842 static void __exit ipip_fini(void)
843 {
844         if (xfrm4_tunnel_deregister(&ipip_handler, AF_INET))
845                 printk(KERN_INFO "ipip close: can't deregister tunnel\n");
846
847         unregister_pernet_device(&ipip_net_ops);
848 }
849
850 module_init(ipip_init);
851 module_exit(ipip_fini);
852 MODULE_LICENSE("GPL");