1/*
2 * File: pn_dev.c
3 *
4 * Phonet network device
5 *
6 * Copyright (C) 2008 Nokia Corporation.
7 *
8 * Authors: Sakari Ailus <sakari.ailus@nokia.com>
9 *          Rémi Denis-Courmont
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
37struct phonet_routes {
38	struct mutex		lock;
39	struct net_device __rcu	*table[64];
40};
41
42struct phonet_net {
43	struct phonet_device_list pndevs;
44	struct phonet_routes routes;
45};
46
47static int phonet_net_id __read_mostly;
48
49static struct phonet_net *phonet_pernet(struct net *net)
50{
51	BUG_ON(!net);
52
53	return net_generic(net, phonet_net_id);
54}
55
56struct 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. */
63static 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
77static 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
90static 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
102static 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
124struct 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
146int 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
165int 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		kfree_rcu(pnd, rcu);
184
185	return err;
186}
187
188/* Gets a source address toward a destination, through a interface. */
189u8 phonet_address_get(struct net_device *dev, u8 daddr)
190{
191	struct phonet_device *pnd;
192	u8 saddr;
193
194	rcu_read_lock();
195	pnd = __phonet_get_rcu(dev);
196	if (pnd) {
197		BUG_ON(bitmap_empty(pnd->addrs, 64));
198
199		/* Use same source address as destination, if possible */
200		if (test_bit(daddr >> 2, pnd->addrs))
201			saddr = daddr;
202		else
203			saddr = find_first_bit(pnd->addrs, 64) << 2;
204	} else
205		saddr = PN_NO_ADDR;
206	rcu_read_unlock();
207
208	if (saddr == PN_NO_ADDR) {
209		/* Fallback to another device */
210		struct net_device *def_dev;
211
212		def_dev = phonet_device_get(dev_net(dev));
213		if (def_dev) {
214			if (def_dev != dev)
215				saddr = phonet_address_get(def_dev, daddr);
216			dev_put(def_dev);
217		}
218	}
219	return saddr;
220}
221
222int phonet_address_lookup(struct net *net, u8 addr)
223{
224	struct phonet_device_list *pndevs = phonet_device_list(net);
225	struct phonet_device *pnd;
226	int err = -EADDRNOTAVAIL;
227
228	rcu_read_lock();
229	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
230		/* Don't allow unregistering devices! */
231		if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
232				((pnd->netdev->flags & IFF_UP)) != IFF_UP)
233			continue;
234
235		if (test_bit(addr >> 2, pnd->addrs)) {
236			err = 0;
237			goto found;
238		}
239	}
240found:
241	rcu_read_unlock();
242	return err;
243}
244
245/* automatically configure a Phonet device, if supported */
246static int phonet_device_autoconf(struct net_device *dev)
247{
248	struct if_phonet_req req;
249	int ret;
250
251	if (!dev->netdev_ops->ndo_do_ioctl)
252		return -EOPNOTSUPP;
253
254	ret = dev->netdev_ops->ndo_do_ioctl(dev, (struct ifreq *)&req,
255						SIOCPNGAUTOCONF);
256	if (ret < 0)
257		return ret;
258
259	ASSERT_RTNL();
260	ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
261	if (ret)
262		return ret;
263	phonet_address_notify(RTM_NEWADDR, dev,
264				req.ifr_phonet_autoconf.device);
265	return 0;
266}
267
268static void phonet_route_autodel(struct net_device *dev)
269{
270	struct phonet_net *pnn = phonet_pernet(dev_net(dev));
271	unsigned int i;
272	DECLARE_BITMAP(deleted, 64);
273
274	/* Remove left-over Phonet routes */
275	bitmap_zero(deleted, 64);
276	mutex_lock(&pnn->routes.lock);
277	for (i = 0; i < 64; i++)
278		if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
279			RCU_INIT_POINTER(pnn->routes.table[i], NULL);
280			set_bit(i, deleted);
281		}
282	mutex_unlock(&pnn->routes.lock);
283
284	if (bitmap_empty(deleted, 64))
285		return; /* short-circuit RCU */
286	synchronize_rcu();
287	for_each_set_bit(i, deleted, 64) {
288		rtm_phonet_notify(RTM_DELROUTE, dev, i);
289		dev_put(dev);
290	}
291}
292
293/* notify Phonet of device events */
294static int phonet_device_notify(struct notifier_block *me, unsigned long what,
295				void *ptr)
296{
297	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
298
299	switch (what) {
300	case NETDEV_REGISTER:
301		if (dev->type == ARPHRD_PHONET)
302			phonet_device_autoconf(dev);
303		break;
304	case NETDEV_UNREGISTER:
305		phonet_device_destroy(dev);
306		phonet_route_autodel(dev);
307		break;
308	}
309	return 0;
310
311}
312
313static struct notifier_block phonet_device_notifier = {
314	.notifier_call = phonet_device_notify,
315	.priority = 0,
316};
317
318/* Per-namespace Phonet devices handling */
319static int __net_init phonet_init_net(struct net *net)
320{
321	struct phonet_net *pnn = phonet_pernet(net);
322
323	if (!proc_create("phonet", 0, net->proc_net, &pn_sock_seq_fops))
324		return -ENOMEM;
325
326	INIT_LIST_HEAD(&pnn->pndevs.list);
327	mutex_init(&pnn->pndevs.lock);
328	mutex_init(&pnn->routes.lock);
329	return 0;
330}
331
332static void __net_exit phonet_exit_net(struct net *net)
333{
334	remove_proc_entry("phonet", net->proc_net);
335}
336
337static struct pernet_operations phonet_net_ops = {
338	.init = phonet_init_net,
339	.exit = phonet_exit_net,
340	.id   = &phonet_net_id,
341	.size = sizeof(struct phonet_net),
342};
343
344/* Initialize Phonet devices list */
345int __init phonet_device_init(void)
346{
347	int err = register_pernet_subsys(&phonet_net_ops);
348	if (err)
349		return err;
350
351	proc_create("pnresource", 0, init_net.proc_net, &pn_res_seq_fops);
352	register_netdevice_notifier(&phonet_device_notifier);
353	err = phonet_netlink_register();
354	if (err)
355		phonet_device_exit();
356	return err;
357}
358
359void phonet_device_exit(void)
360{
361	rtnl_unregister_all(PF_PHONET);
362	unregister_netdevice_notifier(&phonet_device_notifier);
363	unregister_pernet_subsys(&phonet_net_ops);
364	remove_proc_entry("pnresource", init_net.proc_net);
365}
366
367int phonet_route_add(struct net_device *dev, u8 daddr)
368{
369	struct phonet_net *pnn = phonet_pernet(dev_net(dev));
370	struct phonet_routes *routes = &pnn->routes;
371	int err = -EEXIST;
372
373	daddr = daddr >> 2;
374	mutex_lock(&routes->lock);
375	if (routes->table[daddr] == NULL) {
376		rcu_assign_pointer(routes->table[daddr], dev);
377		dev_hold(dev);
378		err = 0;
379	}
380	mutex_unlock(&routes->lock);
381	return err;
382}
383
384int phonet_route_del(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
389	daddr = daddr >> 2;
390	mutex_lock(&routes->lock);
391	if (rcu_access_pointer(routes->table[daddr]) == dev)
392		RCU_INIT_POINTER(routes->table[daddr], NULL);
393	else
394		dev = NULL;
395	mutex_unlock(&routes->lock);
396
397	if (!dev)
398		return -ENOENT;
399	synchronize_rcu();
400	dev_put(dev);
401	return 0;
402}
403
404struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
405{
406	struct phonet_net *pnn = phonet_pernet(net);
407	struct phonet_routes *routes = &pnn->routes;
408	struct net_device *dev;
409
410	daddr >>= 2;
411	dev = rcu_dereference(routes->table[daddr]);
412	return dev;
413}
414
415struct net_device *phonet_route_output(struct net *net, u8 daddr)
416{
417	struct phonet_net *pnn = phonet_pernet(net);
418	struct phonet_routes *routes = &pnn->routes;
419	struct net_device *dev;
420
421	daddr >>= 2;
422	rcu_read_lock();
423	dev = rcu_dereference(routes->table[daddr]);
424	if (dev)
425		dev_hold(dev);
426	rcu_read_unlock();
427
428	if (!dev)
429		dev = phonet_device_get(net); /* Default route */
430	return dev;
431}
432