xref: /openbmc/linux/net/phonet/pn_dev.c (revision 7dd65feb)
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/netdevice.h>
29 #include <linux/phonet.h>
30 #include <linux/proc_fs.h>
31 #include <linux/if_arp.h>
32 #include <net/sock.h>
33 #include <net/netns/generic.h>
34 #include <net/phonet/pn_dev.h>
35 
36 struct phonet_routes {
37 	struct mutex		lock;
38 	struct net_device	*table[64];
39 };
40 
41 struct phonet_net {
42 	struct phonet_device_list pndevs;
43 	struct phonet_routes routes;
44 };
45 
46 int phonet_net_id __read_mostly;
47 
48 struct phonet_device_list *phonet_device_list(struct net *net)
49 {
50 	struct phonet_net *pnn = net_generic(net, phonet_net_id);
51 	return &pnn->pndevs;
52 }
53 
54 /* Allocate new Phonet device. */
55 static struct phonet_device *__phonet_device_alloc(struct net_device *dev)
56 {
57 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
58 	struct phonet_device *pnd = kmalloc(sizeof(*pnd), GFP_ATOMIC);
59 	if (pnd == NULL)
60 		return NULL;
61 	pnd->netdev = dev;
62 	bitmap_zero(pnd->addrs, 64);
63 
64 	BUG_ON(!mutex_is_locked(&pndevs->lock));
65 	list_add_rcu(&pnd->list, &pndevs->list);
66 	return pnd;
67 }
68 
69 static struct phonet_device *__phonet_get(struct net_device *dev)
70 {
71 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
72 	struct phonet_device *pnd;
73 
74 	BUG_ON(!mutex_is_locked(&pndevs->lock));
75 	list_for_each_entry(pnd, &pndevs->list, list) {
76 		if (pnd->netdev == dev)
77 			return pnd;
78 	}
79 	return NULL;
80 }
81 
82 static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
83 {
84 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
85 	struct phonet_device *pnd;
86 
87 	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
88 		if (pnd->netdev == dev)
89 			return pnd;
90 	}
91 	return NULL;
92 }
93 
94 static void phonet_device_destroy(struct net_device *dev)
95 {
96 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
97 	struct phonet_device *pnd;
98 
99 	ASSERT_RTNL();
100 
101 	mutex_lock(&pndevs->lock);
102 	pnd = __phonet_get(dev);
103 	if (pnd)
104 		list_del_rcu(&pnd->list);
105 	mutex_unlock(&pndevs->lock);
106 
107 	if (pnd) {
108 		u8 addr;
109 
110 		for (addr = find_first_bit(pnd->addrs, 64); addr < 64;
111 			addr = find_next_bit(pnd->addrs, 64, 1+addr))
112 			phonet_address_notify(RTM_DELADDR, dev, addr);
113 		kfree(pnd);
114 	}
115 }
116 
117 struct net_device *phonet_device_get(struct net *net)
118 {
119 	struct phonet_device_list *pndevs = phonet_device_list(net);
120 	struct phonet_device *pnd;
121 	struct net_device *dev = NULL;
122 
123 	rcu_read_lock();
124 	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
125 		dev = pnd->netdev;
126 		BUG_ON(!dev);
127 
128 		if ((dev->reg_state == NETREG_REGISTERED) &&
129 			((pnd->netdev->flags & IFF_UP)) == IFF_UP)
130 			break;
131 		dev = NULL;
132 	}
133 	if (dev)
134 		dev_hold(dev);
135 	rcu_read_unlock();
136 	return dev;
137 }
138 
139 int phonet_address_add(struct net_device *dev, u8 addr)
140 {
141 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
142 	struct phonet_device *pnd;
143 	int err = 0;
144 
145 	mutex_lock(&pndevs->lock);
146 	/* Find or create Phonet-specific device data */
147 	pnd = __phonet_get(dev);
148 	if (pnd == NULL)
149 		pnd = __phonet_device_alloc(dev);
150 	if (unlikely(pnd == NULL))
151 		err = -ENOMEM;
152 	else if (test_and_set_bit(addr >> 2, pnd->addrs))
153 		err = -EEXIST;
154 	mutex_unlock(&pndevs->lock);
155 	return err;
156 }
157 
158 int phonet_address_del(struct net_device *dev, u8 addr)
159 {
160 	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
161 	struct phonet_device *pnd;
162 	int err = 0;
163 
164 	mutex_lock(&pndevs->lock);
165 	pnd = __phonet_get(dev);
166 	if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
167 		err = -EADDRNOTAVAIL;
168 		pnd = NULL;
169 	} else if (bitmap_empty(pnd->addrs, 64))
170 		list_del_rcu(&pnd->list);
171 	else
172 		pnd = NULL;
173 	mutex_unlock(&pndevs->lock);
174 
175 	if (pnd) {
176 		synchronize_rcu();
177 		kfree(pnd);
178 	}
179 	return err;
180 }
181 
182 /* Gets a source address toward a destination, through a interface. */
183 u8 phonet_address_get(struct net_device *dev, u8 daddr)
184 {
185 	struct phonet_device *pnd;
186 	u8 saddr;
187 
188 	rcu_read_lock();
189 	pnd = __phonet_get_rcu(dev);
190 	if (pnd) {
191 		BUG_ON(bitmap_empty(pnd->addrs, 64));
192 
193 		/* Use same source address as destination, if possible */
194 		if (test_bit(daddr >> 2, pnd->addrs))
195 			saddr = daddr;
196 		else
197 			saddr = find_first_bit(pnd->addrs, 64) << 2;
198 	} else
199 		saddr = PN_NO_ADDR;
200 	rcu_read_unlock();
201 
202 	if (saddr == PN_NO_ADDR) {
203 		/* Fallback to another device */
204 		struct net_device *def_dev;
205 
206 		def_dev = phonet_device_get(dev_net(dev));
207 		if (def_dev) {
208 			if (def_dev != dev)
209 				saddr = phonet_address_get(def_dev, daddr);
210 			dev_put(def_dev);
211 		}
212 	}
213 	return saddr;
214 }
215 
216 int phonet_address_lookup(struct net *net, u8 addr)
217 {
218 	struct phonet_device_list *pndevs = phonet_device_list(net);
219 	struct phonet_device *pnd;
220 	int err = -EADDRNOTAVAIL;
221 
222 	rcu_read_lock();
223 	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
224 		/* Don't allow unregistering devices! */
225 		if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
226 				((pnd->netdev->flags & IFF_UP)) != IFF_UP)
227 			continue;
228 
229 		if (test_bit(addr >> 2, pnd->addrs)) {
230 			err = 0;
231 			goto found;
232 		}
233 	}
234 found:
235 	rcu_read_unlock();
236 	return err;
237 }
238 
239 /* automatically configure a Phonet device, if supported */
240 static int phonet_device_autoconf(struct net_device *dev)
241 {
242 	struct if_phonet_req req;
243 	int ret;
244 
245 	if (!dev->netdev_ops->ndo_do_ioctl)
246 		return -EOPNOTSUPP;
247 
248 	ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
249 						SIOCPNGAUTOCONF);
250 	if (ret < 0)
251 		return ret;
252 
253 	ASSERT_RTNL();
254 	ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
255 	if (ret)
256 		return ret;
257 	phonet_address_notify(RTM_NEWADDR, dev,
258 				req.ifr_phonet_autoconf.device);
259 	return 0;
260 }
261 
262 static void phonet_route_autodel(struct net_device *dev)
263 {
264 	struct phonet_net *pnn = net_generic(dev_net(dev), phonet_net_id);
265 	unsigned i;
266 	DECLARE_BITMAP(deleted, 64);
267 
268 	/* Remove left-over Phonet routes */
269 	bitmap_zero(deleted, 64);
270 	mutex_lock(&pnn->routes.lock);
271 	for (i = 0; i < 64; i++)
272 		if (dev == pnn->routes.table[i]) {
273 			rcu_assign_pointer(pnn->routes.table[i], NULL);
274 			set_bit(i, deleted);
275 		}
276 	mutex_unlock(&pnn->routes.lock);
277 
278 	if (bitmap_empty(deleted, 64))
279 		return; /* short-circuit RCU */
280 	synchronize_rcu();
281 	for (i = find_first_bit(deleted, 64); i < 64;
282 			i = find_next_bit(deleted, 64, i + 1)) {
283 		rtm_phonet_notify(RTM_DELROUTE, dev, i);
284 		dev_put(dev);
285 	}
286 }
287 
288 /* notify Phonet of device events */
289 static int phonet_device_notify(struct notifier_block *me, unsigned long what,
290 				void *arg)
291 {
292 	struct net_device *dev = arg;
293 
294 	switch (what) {
295 	case NETDEV_REGISTER:
296 		if (dev->type == ARPHRD_PHONET)
297 			phonet_device_autoconf(dev);
298 		break;
299 	case NETDEV_UNREGISTER:
300 		phonet_device_destroy(dev);
301 		phonet_route_autodel(dev);
302 		break;
303 	}
304 	return 0;
305 
306 }
307 
308 static struct notifier_block phonet_device_notifier = {
309 	.notifier_call = phonet_device_notify,
310 	.priority = 0,
311 };
312 
313 /* Per-namespace Phonet devices handling */
314 static int phonet_init_net(struct net *net)
315 {
316 	struct phonet_net *pnn = net_generic(net, phonet_net_id);
317 
318 	if (!proc_net_fops_create(net, "phonet", 0, &pn_sock_seq_fops))
319 		return -ENOMEM;
320 
321 	INIT_LIST_HEAD(&pnn->pndevs.list);
322 	mutex_init(&pnn->pndevs.lock);
323 	mutex_init(&pnn->routes.lock);
324 	return 0;
325 }
326 
327 static void phonet_exit_net(struct net *net)
328 {
329 	struct phonet_net *pnn = net_generic(net, phonet_net_id);
330 	struct net_device *dev;
331 	unsigned i;
332 
333 	rtnl_lock();
334 	for_each_netdev(net, dev)
335 		phonet_device_destroy(dev);
336 
337 	for (i = 0; i < 64; i++) {
338 		dev = pnn->routes.table[i];
339 		if (dev) {
340 			rtm_phonet_notify(RTM_DELROUTE, dev, i);
341 			dev_put(dev);
342 		}
343 	}
344 	rtnl_unlock();
345 
346 	proc_net_remove(net, "phonet");
347 }
348 
349 static struct pernet_operations phonet_net_ops = {
350 	.init = phonet_init_net,
351 	.exit = phonet_exit_net,
352 	.id   = &phonet_net_id,
353 	.size = sizeof(struct phonet_net),
354 };
355 
356 /* Initialize Phonet devices list */
357 int __init phonet_device_init(void)
358 {
359 	int err = register_pernet_device(&phonet_net_ops);
360 	if (err)
361 		return err;
362 
363 	register_netdevice_notifier(&phonet_device_notifier);
364 	err = phonet_netlink_register();
365 	if (err)
366 		phonet_device_exit();
367 	return err;
368 }
369 
370 void phonet_device_exit(void)
371 {
372 	rtnl_unregister_all(PF_PHONET);
373 	unregister_netdevice_notifier(&phonet_device_notifier);
374 	unregister_pernet_device(&phonet_net_ops);
375 }
376 
377 int phonet_route_add(struct net_device *dev, u8 daddr)
378 {
379 	struct phonet_net *pnn = net_generic(dev_net(dev), phonet_net_id);
380 	struct phonet_routes *routes = &pnn->routes;
381 	int err = -EEXIST;
382 
383 	daddr = daddr >> 2;
384 	mutex_lock(&routes->lock);
385 	if (routes->table[daddr] == NULL) {
386 		rcu_assign_pointer(routes->table[daddr], dev);
387 		dev_hold(dev);
388 		err = 0;
389 	}
390 	mutex_unlock(&routes->lock);
391 	return err;
392 }
393 
394 int phonet_route_del(struct net_device *dev, u8 daddr)
395 {
396 	struct phonet_net *pnn = net_generic(dev_net(dev), phonet_net_id);
397 	struct phonet_routes *routes = &pnn->routes;
398 
399 	daddr = daddr >> 2;
400 	mutex_lock(&routes->lock);
401 	if (dev == routes->table[daddr])
402 		rcu_assign_pointer(routes->table[daddr], NULL);
403 	else
404 		dev = NULL;
405 	mutex_unlock(&routes->lock);
406 
407 	if (!dev)
408 		return -ENOENT;
409 	synchronize_rcu();
410 	dev_put(dev);
411 	return 0;
412 }
413 
414 struct net_device *phonet_route_get(struct net *net, u8 daddr)
415 {
416 	struct phonet_net *pnn = net_generic(net, phonet_net_id);
417 	struct phonet_routes *routes = &pnn->routes;
418 	struct net_device *dev;
419 
420 	ASSERT_RTNL(); /* no need to hold the device */
421 
422 	daddr >>= 2;
423 	rcu_read_lock();
424 	dev = rcu_dereference(routes->table[daddr]);
425 	rcu_read_unlock();
426 	return dev;
427 }
428 
429 struct net_device *phonet_route_output(struct net *net, u8 daddr)
430 {
431 	struct phonet_net *pnn = net_generic(net, phonet_net_id);
432 	struct phonet_routes *routes = &pnn->routes;
433 	struct net_device *dev;
434 
435 	daddr >>= 2;
436 	rcu_read_lock();
437 	dev = rcu_dereference(routes->table[daddr]);
438 	if (dev)
439 		dev_hold(dev);
440 	rcu_read_unlock();
441 
442 	if (!dev)
443 		dev = phonet_device_get(net); /* Default route */
444 	return dev;
445 }
446