1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * File: pn_dev.c
4 *
5 * Phonet network device
6 *
7 * Copyright (C) 2008 Nokia Corporation.
8 *
9 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
10 * Rémi Denis-Courmont
11 */
12
13 #include <linux/kernel.h>
14 #include <linux/net.h>
15 #include <linux/slab.h>
16 #include <linux/netdevice.h>
17 #include <linux/phonet.h>
18 #include <linux/proc_fs.h>
19 #include <linux/if_arp.h>
20 #include <net/sock.h>
21 #include <net/netns/generic.h>
22 #include <net/phonet/pn_dev.h>
23
24 struct phonet_routes {
25 struct mutex lock;
26 struct net_device __rcu *table[64];
27 };
28
29 struct phonet_net {
30 struct phonet_device_list pndevs;
31 struct phonet_routes routes;
32 };
33
34 static unsigned int phonet_net_id __read_mostly;
35
phonet_pernet(struct net * net)36 static struct phonet_net *phonet_pernet(struct net *net)
37 {
38 return net_generic(net, phonet_net_id);
39 }
40
phonet_device_list(struct net * net)41 struct phonet_device_list *phonet_device_list(struct net *net)
42 {
43 struct phonet_net *pnn = phonet_pernet(net);
44 return &pnn->pndevs;
45 }
46
47 /* Allocate new Phonet device. */
__phonet_device_alloc(struct net_device * dev)48 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
49 {
50 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
51 struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
52 if (pnd == NULL)
53 return NULL;
54 pnd->netdev = dev;
55 bitmap_zero(pnd->addrs, 64);
56
57 BUG_ON(!mutex_is_locked(&pndevs->lock));
58 list_add_rcu(&pnd->list, &pndevs->list);
59 return pnd;
60 }
61
__phonet_get(struct net_device * dev)62 static struct phonet_device *__phonet_get(struct net_device *dev)
63 {
64 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
65 struct phonet_device *pnd;
66
67 BUG_ON(!mutex_is_locked(&pndevs->lock));
68 list_for_each_entry(pnd, &pndevs->list, list) {
69 if (pnd->netdev == dev)
70 return pnd;
71 }
72 return NULL;
73 }
74
__phonet_get_rcu(struct net_device * dev)75 static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
76 {
77 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
78 struct phonet_device *pnd;
79
80 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
81 if (pnd->netdev == dev)
82 return pnd;
83 }
84 return NULL;
85 }
86
phonet_device_destroy(struct net_device * dev)87 static void phonet_device_destroy(struct net_device *dev)
88 {
89 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
90 struct phonet_device *pnd;
91
92 ASSERT_RTNL();
93
94 mutex_lock(&pndevs->lock);
95 pnd = __phonet_get(dev);
96 if (pnd)
97 list_del_rcu(&pnd->list);
98 mutex_unlock(&pndevs->lock);
99
100 if (pnd) {
101 u8 addr;
102
103 for_each_set_bit(addr, pnd->addrs, 64)
104 phonet_address_notify(RTM_DELADDR, dev, addr);
105 kfree(pnd);
106 }
107 }
108
phonet_device_get(struct net * net)109 struct net_device *phonet_device_get(struct net *net)
110 {
111 struct phonet_device_list *pndevs = phonet_device_list(net);
112 struct phonet_device *pnd;
113 struct net_device *dev = NULL;
114
115 rcu_read_lock();
116 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
117 dev = pnd->netdev;
118 BUG_ON(!dev);
119
120 if ((dev->reg_state == NETREG_REGISTERED) &&
121 ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
122 break;
123 dev = NULL;
124 }
125 if (dev)
126 dev_hold(dev);
127 rcu_read_unlock();
128 return dev;
129 }
130
phonet_address_add(struct net_device * dev,u8 addr)131 int phonet_address_add(struct net_device *dev, u8 addr)
132 {
133 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
134 struct phonet_device *pnd;
135 int err = 0;
136
137 mutex_lock(&pndevs->lock);
138 /* Find or create Phonet-specific device data */
139 pnd = __phonet_get(dev);
140 if (pnd == NULL)
141 pnd = __phonet_device_alloc(dev);
142 if (unlikely(pnd == NULL))
143 err = -ENOMEM;
144 else if (test_and_set_bit(addr >> 2, pnd->addrs))
145 err = -EEXIST;
146 mutex_unlock(&pndevs->lock);
147 return err;
148 }
149
phonet_address_del(struct net_device * dev,u8 addr)150 int phonet_address_del(struct net_device *dev, u8 addr)
151 {
152 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
153 struct phonet_device *pnd;
154 int err = 0;
155
156 mutex_lock(&pndevs->lock);
157 pnd = __phonet_get(dev);
158 if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
159 err = -EADDRNOTAVAIL;
160 pnd = NULL;
161 } else if (bitmap_empty(pnd->addrs, 64))
162 list_del_rcu(&pnd->list);
163 else
164 pnd = NULL;
165 mutex_unlock(&pndevs->lock);
166
167 if (pnd)
168 kfree_rcu(pnd, rcu);
169
170 return err;
171 }
172
173 /* Gets a source address toward a destination, through a interface. */
phonet_address_get(struct net_device * dev,u8 daddr)174 u8 phonet_address_get(struct net_device *dev, u8 daddr)
175 {
176 struct phonet_device *pnd;
177 u8 saddr;
178
179 rcu_read_lock();
180 pnd = __phonet_get_rcu(dev);
181 if (pnd) {
182 BUG_ON(bitmap_empty(pnd->addrs, 64));
183
184 /* Use same source address as destination, if possible */
185 if (test_bit(daddr >> 2, pnd->addrs))
186 saddr = daddr;
187 else
188 saddr = find_first_bit(pnd->addrs, 64) << 2;
189 } else
190 saddr = PN_NO_ADDR;
191 rcu_read_unlock();
192
193 if (saddr == PN_NO_ADDR) {
194 /* Fallback to another device */
195 struct net_device *def_dev;
196
197 def_dev = phonet_device_get(dev_net(dev));
198 if (def_dev) {
199 if (def_dev != dev)
200 saddr = phonet_address_get(def_dev, daddr);
201 dev_put(def_dev);
202 }
203 }
204 return saddr;
205 }
206
phonet_address_lookup(struct net * net,u8 addr)207 int phonet_address_lookup(struct net *net, u8 addr)
208 {
209 struct phonet_device_list *pndevs = phonet_device_list(net);
210 struct phonet_device *pnd;
211 int err = -EADDRNOTAVAIL;
212
213 rcu_read_lock();
214 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
215 /* Don't allow unregistering devices! */
216 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
217 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
218 continue;
219
220 if (test_bit(addr >> 2, pnd->addrs)) {
221 err = 0;
222 goto found;
223 }
224 }
225 found:
226 rcu_read_unlock();
227 return err;
228 }
229
230 /* automatically configure a Phonet device, if supported */
phonet_device_autoconf(struct net_device * dev)231 static int phonet_device_autoconf(struct net_device *dev)
232 {
233 struct if_phonet_req req;
234 int ret;
235
236 if (!dev->netdev_ops->ndo_do_ioctl)
237 return -EOPNOTSUPP;
238
239 ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
240 SIOCPNGAUTOCONF);
241 if (ret < 0)
242 return ret;
243
244 ASSERT_RTNL();
245 ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
246 if (ret)
247 return ret;
248 phonet_address_notify(RTM_NEWADDR, dev,
249 req.ifr_phonet_autoconf.device);
250 return 0;
251 }
252
phonet_route_autodel(struct net_device * dev)253 static void phonet_route_autodel(struct net_device *dev)
254 {
255 struct phonet_net *pnn = phonet_pernet(dev_net(dev));
256 unsigned int i;
257 DECLARE_BITMAP(deleted, 64);
258
259 /* Remove left-over Phonet routes */
260 bitmap_zero(deleted, 64);
261 mutex_lock(&pnn->routes.lock);
262 for (i = 0; i < 64; i++)
263 if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
264 RCU_INIT_POINTER(pnn->routes.table[i], NULL);
265 set_bit(i, deleted);
266 }
267 mutex_unlock(&pnn->routes.lock);
268
269 if (bitmap_empty(deleted, 64))
270 return; /* short-circuit RCU */
271 synchronize_rcu();
272 for_each_set_bit(i, deleted, 64) {
273 rtm_phonet_notify(RTM_DELROUTE, dev, i);
274 dev_put(dev);
275 }
276 }
277
278 /* notify Phonet of device events */
phonet_device_notify(struct notifier_block * me,unsigned long what,void * ptr)279 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
280 void *ptr)
281 {
282 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
283
284 switch (what) {
285 case NETDEV_REGISTER:
286 if (dev->type == ARPHRD_PHONET)
287 phonet_device_autoconf(dev);
288 break;
289 case NETDEV_UNREGISTER:
290 phonet_device_destroy(dev);
291 phonet_route_autodel(dev);
292 break;
293 }
294 return 0;
295
296 }
297
298 static struct notifier_block phonet_device_notifier = {
299 .notifier_call = phonet_device_notify,
300 .priority = 0,
301 };
302
303 /* Per-namespace Phonet devices handling */
phonet_init_net(struct net * net)304 static int __net_init phonet_init_net(struct net *net)
305 {
306 struct phonet_net *pnn = phonet_pernet(net);
307
308 if (!proc_create_net("phonet", 0, net->proc_net, &pn_sock_seq_ops,
309 sizeof(struct seq_net_private)))
310 return -ENOMEM;
311
312 INIT_LIST_HEAD(&pnn->pndevs.list);
313 mutex_init(&pnn->pndevs.lock);
314 mutex_init(&pnn->routes.lock);
315 return 0;
316 }
317
phonet_exit_net(struct net * net)318 static void __net_exit phonet_exit_net(struct net *net)
319 {
320 struct phonet_net *pnn = phonet_pernet(net);
321
322 remove_proc_entry("phonet", net->proc_net);
323 WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
324 }
325
326 static struct pernet_operations phonet_net_ops = {
327 .init = phonet_init_net,
328 .exit = phonet_exit_net,
329 .id = &phonet_net_id,
330 .size = sizeof(struct phonet_net),
331 };
332
333 /* Initialize Phonet devices list */
phonet_device_init(void)334 int __init phonet_device_init(void)
335 {
336 int err = register_pernet_subsys(&phonet_net_ops);
337 if (err)
338 return err;
339
340 proc_create_net("pnresource", 0, init_net.proc_net, &pn_res_seq_ops,
341 sizeof(struct seq_net_private));
342 register_netdevice_notifier(&phonet_device_notifier);
343 err = phonet_netlink_register();
344 if (err)
345 phonet_device_exit();
346 return err;
347 }
348
phonet_device_exit(void)349 void phonet_device_exit(void)
350 {
351 rtnl_unregister_all(PF_PHONET);
352 unregister_netdevice_notifier(&phonet_device_notifier);
353 unregister_pernet_subsys(&phonet_net_ops);
354 remove_proc_entry("pnresource", init_net.proc_net);
355 }
356
phonet_route_add(struct net_device * dev,u8 daddr)357 int phonet_route_add(struct net_device *dev, u8 daddr)
358 {
359 struct phonet_net *pnn = phonet_pernet(dev_net(dev));
360 struct phonet_routes *routes = &pnn->routes;
361 int err = -EEXIST;
362
363 daddr = daddr >> 2;
364 mutex_lock(&routes->lock);
365 if (routes->table[daddr] == NULL) {
366 rcu_assign_pointer(routes->table[daddr], dev);
367 dev_hold(dev);
368 err = 0;
369 }
370 mutex_unlock(&routes->lock);
371 return err;
372 }
373
phonet_route_del(struct net_device * dev,u8 daddr)374 int phonet_route_del(struct net_device *dev, u8 daddr)
375 {
376 struct phonet_net *pnn = phonet_pernet(dev_net(dev));
377 struct phonet_routes *routes = &pnn->routes;
378
379 daddr = daddr >> 2;
380 mutex_lock(&routes->lock);
381 if (rcu_access_pointer(routes->table[daddr]) == dev)
382 RCU_INIT_POINTER(routes->table[daddr], NULL);
383 else
384 dev = NULL;
385 mutex_unlock(&routes->lock);
386
387 if (!dev)
388 return -ENOENT;
389 synchronize_rcu();
390 dev_put(dev);
391 return 0;
392 }
393
phonet_route_get_rcu(struct net * net,u8 daddr)394 struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
395 {
396 struct phonet_net *pnn = phonet_pernet(net);
397 struct phonet_routes *routes = &pnn->routes;
398 struct net_device *dev;
399
400 daddr >>= 2;
401 dev = rcu_dereference(routes->table[daddr]);
402 return dev;
403 }
404
phonet_route_output(struct net * net,u8 daddr)405 struct net_device *phonet_route_output(struct net *net, u8 daddr)
406 {
407 struct phonet_net *pnn = phonet_pernet(net);
408 struct phonet_routes *routes = &pnn->routes;
409 struct net_device *dev;
410
411 daddr >>= 2;
412 rcu_read_lock();
413 dev = rcu_dereference(routes->table[daddr]);
414 if (dev)
415 dev_hold(dev);
416 rcu_read_unlock();
417
418 if (!dev)
419 dev = phonet_device_get(net); /* Default route */
420 return dev;
421 }
422