xref: /openbmc/linux/net/phonet/pn_dev.c (revision 565d76cb)
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(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 	ASSERT_RTNL(); /* no need to hold the device */
436 
437 	daddr >>= 2;
438 	rcu_read_lock();
439 	dev = rcu_dereference(routes->table[daddr]);
440 	rcu_read_unlock();
441 	return dev;
442 }
443 
444 struct net_device *phonet_route_output(struct net *net, u8 daddr)
445 {
446 	struct phonet_net *pnn = phonet_pernet(net);
447 	struct phonet_routes *routes = &pnn->routes;
448 	struct net_device *dev;
449 
450 	daddr >>= 2;
451 	rcu_read_lock();
452 	dev = rcu_dereference(routes->table[daddr]);
453 	if (dev)
454 		dev_hold(dev);
455 	rcu_read_unlock();
456 
457 	if (!dev)
458 		dev = phonet_device_get(net); /* Default route */
459 	return dev;
460 }
461