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/net/phonet/pn_dev.c

http://github.com/mirrors/linux
C | 421 lines | 335 code | 64 blank | 22 comment | 54 complexity | 602c6336c7ffc72db64c2ea12f31abe7 MD5 | raw file
  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 *          RĂ©mi 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
 24struct phonet_routes {
 25	struct mutex		lock;
 26	struct net_device __rcu	*table[64];
 27};
 28
 29struct phonet_net {
 30	struct phonet_device_list pndevs;
 31	struct phonet_routes routes;
 32};
 33
 34static unsigned int phonet_net_id __read_mostly;
 35
 36static struct phonet_net *phonet_pernet(struct net *net)
 37{
 38	return net_generic(net, phonet_net_id);
 39}
 40
 41struct 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. */
 48static 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
 62static 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
 75static 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
 87static 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
109struct 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
131int 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
150int 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. */
174u8 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
207int 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	}
225found:
226	rcu_read_unlock();
227	return err;
228}
229
230/* automatically configure a Phonet device, if supported */
231static 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
253static 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 */
279static 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
298static struct notifier_block phonet_device_notifier = {
299	.notifier_call = phonet_device_notify,
300	.priority = 0,
301};
302
303/* Per-namespace Phonet devices handling */
304static 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
318static 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
326static 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 */
334int __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
349void 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
357int 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
374int 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
394struct 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
405struct 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}