ipv4: fix redirect handling
[linux-2.6.git] / net / phonet / pn_dev.c
1 /*
2  * File: pn_dev.c
3  *
4  * Phonet network device
5  *
6  * Copyright (C) 2008 Nokia Corporation.
7  *
8  * Contact: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
9  * Original author: Sakari Ailus <sakari.ailus@nokia.com>
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License
13  * version 2 as published by the Free Software Foundation.
14  *
15  * This program is distributed in the hope that it will be useful, but
16  * WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
18  * General Public License for more details.
19  *
20  * You should have received a copy of the GNU General Public License
21  * along with this program; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
23  * 02110-1301 USA
24  */
25
26 #include <linux/kernel.h>
27 #include <linux/net.h>
28 #include <linux/slab.h>
29 #include <linux/netdevice.h>
30 #include <linux/phonet.h>
31 #include <linux/proc_fs.h>
32 #include <linux/if_arp.h>
33 #include <net/sock.h>
34 #include <net/netns/generic.h>
35 #include <net/phonet/pn_dev.h>
36
37 struct phonet_routes {
38         struct mutex            lock;
39         struct net_device       *table[64];
40 };
41
42 struct phonet_net {
43         struct phonet_device_list pndevs;
44         struct phonet_routes routes;
45 };
46
47 int phonet_net_id __read_mostly;
48
49 static struct phonet_net *phonet_pernet(struct net *net)
50 {
51         BUG_ON(!net);
52
53         return net_generic(net, phonet_net_id);
54 }
55
56 struct phonet_device_list *phonet_device_list(struct net *net)
57 {
58         struct phonet_net *pnn = phonet_pernet(net);
59         return &pnn->pndevs;
60 }
61
62 /* Allocate new Phonet device. */
63 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
64 {
65         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
66         struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
67         if (pnd == NULL)
68                 return NULL;
69         pnd->netdev = dev;
70         bitmap_zero(pnd->addrs, 64);
71
72         BUG_ON(!mutex_is_locked(&pndevs->lock));
73         list_add_rcu(&pnd->list, &pndevs->list);
74         return pnd;
75 }
76
77 static struct phonet_device *__phonet_get(struct net_device *dev)
78 {
79         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
80         struct phonet_device *pnd;
81
82         BUG_ON(!mutex_is_locked(&pndevs->lock));
83         list_for_each_entry(pnd, &pndevs->list, list) {
84                 if (pnd->netdev == dev)
85                         return pnd;
86         }
87         return NULL;
88 }
89
90 static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
91 {
92         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
93         struct phonet_device *pnd;
94
95         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
96                 if (pnd->netdev == dev)
97                         return pnd;
98         }
99         return NULL;
100 }
101
102 static void phonet_device_destroy(struct net_device *dev)
103 {
104         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
105         struct phonet_device *pnd;
106
107         ASSERT_RTNL();
108
109         mutex_lock(&pndevs->lock);
110         pnd = __phonet_get(dev);
111         if (pnd)
112                 list_del_rcu(&pnd->list);
113         mutex_unlock(&pndevs->lock);
114
115         if (pnd) {
116                 u8 addr;
117
118                 for_each_set_bit(addr, pnd->addrs, 64)
119                         phonet_address_notify(RTM_DELADDR, dev, addr);
120                 kfree(pnd);
121         }
122 }
123
124 struct net_device *phonet_device_get(struct net *net)
125 {
126         struct phonet_device_list *pndevs = phonet_device_list(net);
127         struct phonet_device *pnd;
128         struct net_device *dev = NULL;
129
130         rcu_read_lock();
131         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
132                 dev = pnd->netdev;
133                 BUG_ON(!dev);
134
135                 if ((dev->reg_state == NETREG_REGISTERED) &&
136                         ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
137                         break;
138                 dev = NULL;
139         }
140         if (dev)
141                 dev_hold(dev);
142         rcu_read_unlock();
143         return dev;
144 }
145
146 int phonet_address_add(struct net_device *dev, u8 addr)
147 {
148         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
149         struct phonet_device *pnd;
150         int err = 0;
151
152         mutex_lock(&pndevs->lock);
153         /* Find or create Phonet-specific device data */
154         pnd = __phonet_get(dev);
155         if (pnd == NULL)
156                 pnd = __phonet_device_alloc(dev);
157         if (unlikely(pnd == NULL))
158                 err = -ENOMEM;
159         else if (test_and_set_bit(addr >> 2, pnd->addrs))
160                 err = -EEXIST;
161         mutex_unlock(&pndevs->lock);
162         return err;
163 }
164
165 int phonet_address_del(struct net_device *dev, u8 addr)
166 {
167         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
168         struct phonet_device *pnd;
169         int err = 0;
170
171         mutex_lock(&pndevs->lock);
172         pnd = __phonet_get(dev);
173         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
174                 err = -EADDRNOTAVAIL;
175                 pnd = NULL;
176         } else if (bitmap_empty(pnd->addrs, 64))
177                 list_del_rcu(&pnd->list);
178         else
179                 pnd = NULL;
180         mutex_unlock(&pndevs->lock);
181
182         if (pnd)
183                 kfree_rcu(pnd, rcu);
184
185         return err;
186 }
187
188 /* Gets a source address toward a destination, through a interface. */
189 u8 phonet_address_get(struct net_device *dev, u8 daddr)
190 {
191         struct phonet_device *pnd;
192         u8 saddr;
193
194         rcu_read_lock();
195         pnd = __phonet_get_rcu(dev);
196         if (pnd) {
197                 BUG_ON(bitmap_empty(pnd->addrs, 64));
198
199                 /* Use same source address as destination, if possible */
200                 if (test_bit(daddr >> 2, pnd->addrs))
201                         saddr = daddr;
202                 else
203                         saddr = find_first_bit(pnd->addrs, 64) << 2;
204         } else
205                 saddr = PN_NO_ADDR;
206         rcu_read_unlock();
207
208         if (saddr == PN_NO_ADDR) {
209                 /* Fallback to another device */
210                 struct net_device *def_dev;
211
212                 def_dev = phonet_device_get(dev_net(dev));
213                 if (def_dev) {
214                         if (def_dev != dev)
215                                 saddr = phonet_address_get(def_dev, daddr);
216                         dev_put(def_dev);
217                 }
218         }
219         return saddr;
220 }
221
222 int phonet_address_lookup(struct net *net, u8 addr)
223 {
224         struct phonet_device_list *pndevs = phonet_device_list(net);
225         struct phonet_device *pnd;
226         int err = -EADDRNOTAVAIL;
227
228         rcu_read_lock();
229         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
230                 /* Don't allow unregistering devices! */
231                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
232                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
233                         continue;
234
235                 if (test_bit(addr >> 2, pnd->addrs)) {
236                         err = 0;
237                         goto found;
238                 }
239         }
240 found:
241         rcu_read_unlock();
242         return err;
243 }
244
245 /* automatically configure a Phonet device, if supported */
246 static int phonet_device_autoconf(struct net_device *dev)
247 {
248         struct if_phonet_req req;
249         int ret;
250
251         if (!dev->netdev_ops->ndo_do_ioctl)
252                 return -EOPNOTSUPP;
253
254         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
255                                                 SIOCPNGAUTOCONF);
256         if (ret < 0)
257                 return ret;
258
259         ASSERT_RTNL();
260         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
261         if (ret)
262                 return ret;
263         phonet_address_notify(RTM_NEWADDR, dev,
264                                 req.ifr_phonet_autoconf.device);
265         return 0;
266 }
267
268 static void phonet_route_autodel(struct net_device *dev)
269 {
270         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
271         unsigned i;
272         DECLARE_BITMAP(deleted, 64);
273
274         /* Remove left-over Phonet routes */
275         bitmap_zero(deleted, 64);
276         mutex_lock(&pnn->routes.lock);
277         for (i = 0; i < 64; i++)
278                 if (dev == pnn->routes.table[i]) {
279                         rcu_assign_pointer(pnn->routes.table[i], NULL);
280                         set_bit(i, deleted);
281                 }
282         mutex_unlock(&pnn->routes.lock);
283
284         if (bitmap_empty(deleted, 64))
285                 return; /* short-circuit RCU */
286         synchronize_rcu();
287         for_each_set_bit(i, deleted, 64) {
288                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
289                 dev_put(dev);
290         }
291 }
292
293 /* notify Phonet of device events */
294 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
295                                 void *arg)
296 {
297         struct net_device *dev = arg;
298
299         switch (what) {
300         case NETDEV_REGISTER:
301                 if (dev->type == ARPHRD_PHONET)
302                         phonet_device_autoconf(dev);
303                 break;
304         case NETDEV_UNREGISTER:
305                 phonet_device_destroy(dev);
306                 phonet_route_autodel(dev);
307                 break;
308         }
309         return 0;
310
311 }
312
313 static struct notifier_block phonet_device_notifier = {
314         .notifier_call = phonet_device_notify,
315         .priority = 0,
316 };
317
318 /* Per-namespace Phonet devices handling */
319 static int __net_init phonet_init_net(struct net *net)
320 {
321         struct phonet_net *pnn = phonet_pernet(net);
322
323         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
324                 return -ENOMEM;
325
326         INIT_LIST_HEAD(&pnn->pndevs.list);
327         mutex_init(&pnn->pndevs.lock);
328         mutex_init(&pnn->routes.lock);
329         return 0;
330 }
331
332 static void __net_exit phonet_exit_net(struct net *net)
333 {
334         struct phonet_net *pnn = phonet_pernet(net);
335         struct net_device *dev;
336         unsigned i;
337
338         rtnl_lock();
339         for_each_netdev(net, dev)
340                 phonet_device_destroy(dev);
341
342         for (i = 0; i < 64; i++) {
343                 dev = pnn->routes.table[i];
344                 if (dev) {
345                         rtm_phonet_notify(RTM_DELROUTE, dev, i);
346                         dev_put(dev);
347                 }
348         }
349         rtnl_unlock();
350
351         proc_net_remove(net, "phonet");
352 }
353
354 static struct pernet_operations phonet_net_ops = {
355         .init = phonet_init_net,
356         .exit = phonet_exit_net,
357         .id   = &phonet_net_id,
358         .size = sizeof(struct phonet_net),
359 };
360
361 /* Initialize Phonet devices list */
362 int __init phonet_device_init(void)
363 {
364         int err = register_pernet_device(&phonet_net_ops);
365         if (err)
366                 return err;
367
368         proc_net_fops_create(&init_net, "pnresource", 0, &pn_res_seq_fops);
369         register_netdevice_notifier(&phonet_device_notifier);
370         err = phonet_netlink_register();
371         if (err)
372                 phonet_device_exit();
373         return err;
374 }
375
376 void phonet_device_exit(void)
377 {
378         rtnl_unregister_all(PF_PHONET);
379         unregister_netdevice_notifier(&phonet_device_notifier);
380         unregister_pernet_device(&phonet_net_ops);
381         proc_net_remove(&init_net, "pnresource");
382 }
383
384 int phonet_route_add(struct net_device *dev, u8 daddr)
385 {
386         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
387         struct phonet_routes *routes = &pnn->routes;
388         int err = -EEXIST;
389
390         daddr = daddr >> 2;
391         mutex_lock(&routes->lock);
392         if (routes->table[daddr] == NULL) {
393                 rcu_assign_pointer(routes->table[daddr], dev);
394                 dev_hold(dev);
395                 err = 0;
396         }
397         mutex_unlock(&routes->lock);
398         return err;
399 }
400
401 int phonet_route_del(struct net_device *dev, u8 daddr)
402 {
403         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
404         struct phonet_routes *routes = &pnn->routes;
405
406         daddr = daddr >> 2;
407         mutex_lock(&routes->lock);
408         if (dev == routes->table[daddr])
409                 rcu_assign_pointer(routes->table[daddr], NULL);
410         else
411                 dev = NULL;
412         mutex_unlock(&routes->lock);
413
414         if (!dev)
415                 return -ENOENT;
416         synchronize_rcu();
417         dev_put(dev);
418         return 0;
419 }
420
421 struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
422 {
423         struct phonet_net *pnn = phonet_pernet(net);
424         struct phonet_routes *routes = &pnn->routes;
425         struct net_device *dev;
426
427         daddr >>= 2;
428         dev = rcu_dereference(routes->table[daddr]);
429         return dev;
430 }
431
432 struct net_device *phonet_route_output(struct net *net, u8 daddr)
433 {
434         struct phonet_net *pnn = phonet_pernet(net);
435         struct phonet_routes *routes = &pnn->routes;
436         struct net_device *dev;
437
438         daddr >>= 2;
439         rcu_read_lock();
440         dev = rcu_dereference(routes->table[daddr]);
441         if (dev)
442                 dev_hold(dev);
443         rcu_read_unlock();
444
445         if (!dev)
446                 dev = phonet_device_get(net); /* Default route */
447         return dev;
448 }