net: dont hold rtnl mutex during netlink dump callbacks
[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 static void phonet_device_rcu_free(struct rcu_head *head)
166 {
167         struct phonet_device *pnd;
168
169         pnd = container_of(head, struct phonet_device, rcu);
170         kfree(pnd);
171 }
172
173 int phonet_address_del(struct net_device *dev, u8 addr)
174 {
175         struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
176         struct phonet_device *pnd;
177         int err = 0;
178
179         mutex_lock(&pndevs->lock);
180         pnd = __phonet_get(dev);
181         if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
182                 err = -EADDRNOTAVAIL;
183                 pnd = NULL;
184         } else if (bitmap_empty(pnd->addrs, 64))
185                 list_del_rcu(&pnd->list);
186         else
187                 pnd = NULL;
188         mutex_unlock(&pndevs->lock);
189
190         if (pnd)
191                 call_rcu(&pnd->rcu, phonet_device_rcu_free);
192
193         return err;
194 }
195
196 /* Gets a source address toward a destination, through a interface. */
197 u8 phonet_address_get(struct net_device *dev, u8 daddr)
198 {
199         struct phonet_device *pnd;
200         u8 saddr;
201
202         rcu_read_lock();
203         pnd = __phonet_get_rcu(dev);
204         if (pnd) {
205                 BUG_ON(bitmap_empty(pnd->addrs, 64));
206
207                 /* Use same source address as destination, if possible */
208                 if (test_bit(daddr >> 2, pnd->addrs))
209                         saddr = daddr;
210                 else
211                         saddr = find_first_bit(pnd->addrs, 64) << 2;
212         } else
213                 saddr = PN_NO_ADDR;
214         rcu_read_unlock();
215
216         if (saddr == PN_NO_ADDR) {
217                 /* Fallback to another device */
218                 struct net_device *def_dev;
219
220                 def_dev = phonet_device_get(dev_net(dev));
221                 if (def_dev) {
222                         if (def_dev != dev)
223                                 saddr = phonet_address_get(def_dev, daddr);
224                         dev_put(def_dev);
225                 }
226         }
227         return saddr;
228 }
229
230 int phonet_address_lookup(struct net *net, u8 addr)
231 {
232         struct phonet_device_list *pndevs = phonet_device_list(net);
233         struct phonet_device *pnd;
234         int err = -EADDRNOTAVAIL;
235
236         rcu_read_lock();
237         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
238                 /* Don't allow unregistering devices! */
239                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
240                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
241                         continue;
242
243                 if (test_bit(addr >> 2, pnd->addrs)) {
244                         err = 0;
245                         goto found;
246                 }
247         }
248 found:
249         rcu_read_unlock();
250         return err;
251 }
252
253 /* automatically configure a Phonet device, if supported */
254 static int phonet_device_autoconf(struct net_device *dev)
255 {
256         struct if_phonet_req req;
257         int ret;
258
259         if (!dev->netdev_ops->ndo_do_ioctl)
260                 return -EOPNOTSUPP;
261
262         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
263                                                 SIOCPNGAUTOCONF);
264         if (ret < 0)
265                 return ret;
266
267         ASSERT_RTNL();
268         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
269         if (ret)
270                 return ret;
271         phonet_address_notify(RTM_NEWADDR, dev,
272                                 req.ifr_phonet_autoconf.device);
273         return 0;
274 }
275
276 static void phonet_route_autodel(struct net_device *dev)
277 {
278         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
279         unsigned i;
280         DECLARE_BITMAP(deleted, 64);
281
282         /* Remove left-over Phonet routes */
283         bitmap_zero(deleted, 64);
284         mutex_lock(&pnn->routes.lock);
285         for (i = 0; i < 64; i++)
286                 if (dev == pnn->routes.table[i]) {
287                         rcu_assign_pointer(pnn->routes.table[i], NULL);
288                         set_bit(i, deleted);
289                 }
290         mutex_unlock(&pnn->routes.lock);
291
292         if (bitmap_empty(deleted, 64))
293                 return; /* short-circuit RCU */
294         synchronize_rcu();
295         for_each_set_bit(i, deleted, 64) {
296                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
297                 dev_put(dev);
298         }
299 }
300
301 /* notify Phonet of device events */
302 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
303                                 void *arg)
304 {
305         struct net_device *dev = arg;
306
307         switch (what) {
308         case NETDEV_REGISTER:
309                 if (dev->type == ARPHRD_PHONET)
310                         phonet_device_autoconf(dev);
311                 break;
312         case NETDEV_UNREGISTER:
313                 phonet_device_destroy(dev);
314                 phonet_route_autodel(dev);
315                 break;
316         }
317         return 0;
318
319 }
320
321 static struct notifier_block phonet_device_notifier = {
322         .notifier_call = phonet_device_notify,
323         .priority = 0,
324 };
325
326 /* Per-namespace Phonet devices handling */
327 static int __net_init phonet_init_net(struct net *net)
328 {
329         struct phonet_net *pnn = phonet_pernet(net);
330
331         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
332                 return -ENOMEM;
333
334         INIT_LIST_HEAD(&pnn->pndevs.list);
335         mutex_init(&pnn->pndevs.lock);
336         mutex_init(&pnn->routes.lock);
337         return 0;
338 }
339
340 static void __net_exit phonet_exit_net(struct net *net)
341 {
342         struct phonet_net *pnn = phonet_pernet(net);
343         struct net_device *dev;
344         unsigned i;
345
346         rtnl_lock();
347         for_each_netdev(net, dev)
348                 phonet_device_destroy(dev);
349
350         for (i = 0; i < 64; i++) {
351                 dev = pnn->routes.table[i];
352                 if (dev) {
353                         rtm_phonet_notify(RTM_DELROUTE, dev, i);
354                         dev_put(dev);
355                 }
356         }
357         rtnl_unlock();
358
359         proc_net_remove(net, "phonet");
360 }
361
362 static struct pernet_operations phonet_net_ops = {
363         .init = phonet_init_net,
364         .exit = phonet_exit_net,
365         .id   = &phonet_net_id,
366         .size = sizeof(struct phonet_net),
367 };
368
369 /* Initialize Phonet devices list */
370 int __init phonet_device_init(void)
371 {
372         int err = register_pernet_device(&phonet_net_ops);
373         if (err)
374                 return err;
375
376         proc_net_fops_create(&init_net, "pnresource", 0, &pn_res_seq_fops);
377         register_netdevice_notifier(&phonet_device_notifier);
378         err = phonet_netlink_register();
379         if (err)
380                 phonet_device_exit();
381         return err;
382 }
383
384 void phonet_device_exit(void)
385 {
386         rtnl_unregister_all(PF_PHONET);
387         unregister_netdevice_notifier(&phonet_device_notifier);
388         unregister_pernet_device(&phonet_net_ops);
389         proc_net_remove(&init_net, "pnresource");
390 }
391
392 int phonet_route_add(struct net_device *dev, u8 daddr)
393 {
394         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
395         struct phonet_routes *routes = &pnn->routes;
396         int err = -EEXIST;
397
398         daddr = daddr >> 2;
399         mutex_lock(&routes->lock);
400         if (routes->table[daddr] == NULL) {
401                 rcu_assign_pointer(routes->table[daddr], dev);
402                 dev_hold(dev);
403                 err = 0;
404         }
405         mutex_unlock(&routes->lock);
406         return err;
407 }
408
409 int phonet_route_del(struct net_device *dev, u8 daddr)
410 {
411         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
412         struct phonet_routes *routes = &pnn->routes;
413
414         daddr = daddr >> 2;
415         mutex_lock(&routes->lock);
416         if (dev == routes->table[daddr])
417                 rcu_assign_pointer(routes->table[daddr], NULL);
418         else
419                 dev = NULL;
420         mutex_unlock(&routes->lock);
421
422         if (!dev)
423                 return -ENOENT;
424         synchronize_rcu();
425         dev_put(dev);
426         return 0;
427 }
428
429 struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
430 {
431         struct phonet_net *pnn = phonet_pernet(net);
432         struct phonet_routes *routes = &pnn->routes;
433         struct net_device *dev;
434
435         daddr >>= 2;
436         dev = rcu_dereference(routes->table[daddr]);
437         return dev;
438 }
439
440 struct net_device *phonet_route_output(struct net *net, u8 daddr)
441 {
442         struct phonet_net *pnn = phonet_pernet(net);
443         struct phonet_routes *routes = &pnn->routes;
444         struct net_device *dev;
445
446         daddr >>= 2;
447         rcu_read_lock();
448         dev = rcu_dereference(routes->table[daddr]);
449         if (dev)
450                 dev_hold(dev);
451         rcu_read_unlock();
452
453         if (!dev)
454                 dev = phonet_device_get(net); /* Default route */
455         return dev;
456 }