c33da65769420555a4a3cb60c0d5585519111f11
[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                 synchronize_rcu();
184                 kfree(pnd);
185         }
186         return err;
187 }
188
189 /* Gets a source address toward a destination, through a interface. */
190 u8 phonet_address_get(struct net_device *dev, u8 daddr)
191 {
192         struct phonet_device *pnd;
193         u8 saddr;
194
195         rcu_read_lock();
196         pnd = __phonet_get_rcu(dev);
197         if (pnd) {
198                 BUG_ON(bitmap_empty(pnd->addrs, 64));
199
200                 /* Use same source address as destination, if possible */
201                 if (test_bit(daddr >> 2, pnd->addrs))
202                         saddr = daddr;
203                 else
204                         saddr = find_first_bit(pnd->addrs, 64) << 2;
205         } else
206                 saddr = PN_NO_ADDR;
207         rcu_read_unlock();
208
209         if (saddr == PN_NO_ADDR) {
210                 /* Fallback to another device */
211                 struct net_device *def_dev;
212
213                 def_dev = phonet_device_get(dev_net(dev));
214                 if (def_dev) {
215                         if (def_dev != dev)
216                                 saddr = phonet_address_get(def_dev, daddr);
217                         dev_put(def_dev);
218                 }
219         }
220         return saddr;
221 }
222
223 int phonet_address_lookup(struct net *net, u8 addr)
224 {
225         struct phonet_device_list *pndevs = phonet_device_list(net);
226         struct phonet_device *pnd;
227         int err = -EADDRNOTAVAIL;
228
229         rcu_read_lock();
230         list_for_each_entry_rcu(pnd, &pndevs->list, list) {
231                 /* Don't allow unregistering devices! */
232                 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
233                                 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
234                         continue;
235
236                 if (test_bit(addr >> 2, pnd->addrs)) {
237                         err = 0;
238                         goto found;
239                 }
240         }
241 found:
242         rcu_read_unlock();
243         return err;
244 }
245
246 /* automatically configure a Phonet device, if supported */
247 static int phonet_device_autoconf(struct net_device *dev)
248 {
249         struct if_phonet_req req;
250         int ret;
251
252         if (!dev->netdev_ops->ndo_do_ioctl)
253                 return -EOPNOTSUPP;
254
255         ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
256                                                 SIOCPNGAUTOCONF);
257         if (ret < 0)
258                 return ret;
259
260         ASSERT_RTNL();
261         ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
262         if (ret)
263                 return ret;
264         phonet_address_notify(RTM_NEWADDR, dev,
265                                 req.ifr_phonet_autoconf.device);
266         return 0;
267 }
268
269 static void phonet_route_autodel(struct net_device *dev)
270 {
271         struct phonet_net *pnn = phonet_pernet(dev_net(dev));
272         unsigned i;
273         DECLARE_BITMAP(deleted, 64);
274
275         /* Remove left-over Phonet routes */
276         bitmap_zero(deleted, 64);
277         mutex_lock(&pnn->routes.lock);
278         for (i = 0; i < 64; i++)
279                 if (dev == pnn->routes.table[i]) {
280                         rcu_assign_pointer(pnn->routes.table[i], NULL);
281                         set_bit(i, deleted);
282                 }
283         mutex_unlock(&pnn->routes.lock);
284
285         if (bitmap_empty(deleted, 64))
286                 return; /* short-circuit RCU */
287         synchronize_rcu();
288         for (i = find_first_bit(deleted, 64); i < 64;
289                         i = find_next_bit(deleted, 64, i + 1)) {
290                 rtm_phonet_notify(RTM_DELROUTE, dev, i);
291                 dev_put(dev);
292         }
293 }
294
295 /* notify Phonet of device events */
296 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
297                                 void *arg)
298 {
299         struct net_device *dev = arg;
300
301         switch (what) {
302         case NETDEV_REGISTER:
303                 if (dev->type == ARPHRD_PHONET)
304                         phonet_device_autoconf(dev);
305                 break;
306         case NETDEV_UNREGISTER:
307                 phonet_device_destroy(dev);
308                 phonet_route_autodel(dev);
309                 break;
310         }
311         return 0;
312
313 }
314
315 static struct notifier_block phonet_device_notifier = {
316         .notifier_call = phonet_device_notify,
317         .priority = 0,
318 };
319
320 /* Per-namespace Phonet devices handling */
321 static int __net_init phonet_init_net(struct net *net)
322 {
323         struct phonet_net *pnn = phonet_pernet(net);
324
325         if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
326                 return -ENOMEM;
327
328         INIT_LIST_HEAD(&pnn->pndevs.list);
329         mutex_init(&pnn->pndevs.lock);
330         mutex_init(&pnn->routes.lock);
331         return 0;
332 }
333
334 static void __net_exit phonet_exit_net(struct net *net)
335 {
336         struct phonet_net *pnn = phonet_pernet(net);
337         struct net_device *dev;
338         unsigned i;
339
340         rtnl_lock();
341         for_each_netdev(net, dev)
342                 phonet_device_destroy(dev);
343
344         for (i = 0; i < 64; i++) {
345                 dev = pnn->routes.table[i];
346                 if (dev) {
347                         rtm_phonet_notify(RTM_DELROUTE, dev, i);
348                         dev_put(dev);
349                 }
350         }
351         rtnl_unlock();
352
353         proc_net_remove(net, "phonet");
354 }
355
356 static struct pernet_operations phonet_net_ops = {
357         .init = phonet_init_net,
358         .exit = phonet_exit_net,
359         .id   = &phonet_net_id,
360         .size = sizeof(struct phonet_net),
361 };
362
363 /* Initialize Phonet devices list */
364 int __init phonet_device_init(void)
365 {
366         int err = register_pernet_device(&phonet_net_ops);
367         if (err)
368                 return err;
369
370         register_netdevice_notifier(&phonet_device_notifier);
371         err = phonet_netlink_register();
372         if (err)
373                 phonet_device_exit();
374         return err;
375 }
376
377 void phonet_device_exit(void)
378 {
379         rtnl_unregister_all(PF_PHONET);
380         unregister_netdevice_notifier(&phonet_device_notifier);
381         unregister_pernet_device(&phonet_net_ops);
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(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         ASSERT_RTNL(); /* no need to hold the device */
428
429         daddr >>= 2;
430         rcu_read_lock();
431         dev = rcu_dereference(routes->table[daddr]);
432         rcu_read_unlock();
433         return dev;
434 }
435
436 struct net_device *phonet_route_output(struct net *net, u8 daddr)
437 {
438         struct phonet_net *pnn = phonet_pernet(net);
439         struct phonet_routes *routes = &pnn->routes;
440         struct net_device *dev;
441
442         daddr >>= 2;
443         rcu_read_lock();
444         dev = rcu_dereference(routes->table[daddr]);
445         if (dev)
446                 dev_hold(dev);
447         rcu_read_unlock();
448
449         if (!dev)
450                 dev = phonet_device_get(net); /* Default route */
451         return dev;
452 }