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 *          R��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	dev_hold(dev);
126	rcu_read_unlock();
127	return dev;
128}
129
130int phonet_address_add(struct net_device *dev, u8 addr)
131{
132	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
133	struct phonet_device *pnd;
134	int err = 0;
135
136	mutex_lock(&pndevs->lock);
137	/* Find or create Phonet-specific device data */
138	pnd = __phonet_get(dev);
139	if (pnd == NULL)
140		pnd = __phonet_device_alloc(dev);
141	if (unlikely(pnd == NULL))
142		err = -ENOMEM;
143	else if (test_and_set_bit(addr >> 2, pnd->addrs))
144		err = -EEXIST;
145	mutex_unlock(&pndevs->lock);
146	return err;
147}
148
149int phonet_address_del(struct net_device *dev, u8 addr)
150{
151	struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
152	struct phonet_device *pnd;
153	int err = 0;
154
155	mutex_lock(&pndevs->lock);
156	pnd = __phonet_get(dev);
157	if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
158		err = -EADDRNOTAVAIL;
159		pnd = NULL;
160	} else if (bitmap_empty(pnd->addrs, 64))
161		list_del_rcu(&pnd->list);
162	else
163		pnd = NULL;
164	mutex_unlock(&pndevs->lock);
165
166	if (pnd)
167		kfree_rcu(pnd, rcu);
168
169	return err;
170}
171
172/* Gets a source address toward a destination, through a interface. */
173u8 phonet_address_get(struct net_device *dev, u8 daddr)
174{
175	struct phonet_device *pnd;
176	u8 saddr;
177
178	rcu_read_lock();
179	pnd = __phonet_get_rcu(dev);
180	if (pnd) {
181		BUG_ON(bitmap_empty(pnd->addrs, 64));
182
183		/* Use same source address as destination, if possible */
184		if (test_bit(daddr >> 2, pnd->addrs))
185			saddr = daddr;
186		else
187			saddr = find_first_bit(pnd->addrs, 64) << 2;
188	} else
189		saddr = PN_NO_ADDR;
190	rcu_read_unlock();
191
192	if (saddr == PN_NO_ADDR) {
193		/* Fallback to another device */
194		struct net_device *def_dev;
195
196		def_dev = phonet_device_get(dev_net(dev));
197		if (def_dev) {
198			if (def_dev != dev)
199				saddr = phonet_address_get(def_dev, daddr);
200			dev_put(def_dev);
201		}
202	}
203	return saddr;
204}
205
206int phonet_address_lookup(struct net *net, u8 addr)
207{
208	struct phonet_device_list *pndevs = phonet_device_list(net);
209	struct phonet_device *pnd;
210	int err = -EADDRNOTAVAIL;
211
212	rcu_read_lock();
213	list_for_each_entry_rcu(pnd, &pndevs->list, list) {
214		/* Don't allow unregistering devices! */
215		if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
216				((pnd->netdev->flags & IFF_UP)) != IFF_UP)
217			continue;
218
219		if (test_bit(addr >> 2, pnd->addrs)) {
220			err = 0;
221			goto found;
222		}
223	}
224found:
225	rcu_read_unlock();
226	return err;
227}
228
229/* automatically configure a Phonet device, if supported */
230static int phonet_device_autoconf(struct net_device *dev)
231{
232	struct if_phonet_req req;
233	int ret;
234
235	if (!dev->netdev_ops->ndo_siocdevprivate)
236		return -EOPNOTSUPP;
237
238	ret = dev->netdev_ops->ndo_siocdevprivate(dev, (struct ifreq *)&req,
239						  NULL, SIOCPNGAUTOCONF);
240	if (ret < 0)
241		return ret;
242
243	ASSERT_RTNL();
244	ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
245	if (ret)
246		return ret;
247	phonet_address_notify(RTM_NEWADDR, dev,
248				req.ifr_phonet_autoconf.device);
249	return 0;
250}
251
252static void phonet_route_autodel(struct net_device *dev)
253{
254	struct phonet_net *pnn = phonet_pernet(dev_net(dev));
255	unsigned int i;
256	DECLARE_BITMAP(deleted, 64);
257
258	/* Remove left-over Phonet routes */
259	bitmap_zero(deleted, 64);
260	mutex_lock(&pnn->routes.lock);
261	for (i = 0; i < 64; i++)
262		if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
263			RCU_INIT_POINTER(pnn->routes.table[i], NULL);
264			set_bit(i, deleted);
265		}
266	mutex_unlock(&pnn->routes.lock);
267
268	if (bitmap_empty(deleted, 64))
269		return; /* short-circuit RCU */
270	synchronize_rcu();
271	for_each_set_bit(i, deleted, 64) {
272		rtm_phonet_notify(RTM_DELROUTE, dev, i);
273		dev_put(dev);
274	}
275}
276
277/* notify Phonet of device events */
278static int phonet_device_notify(struct notifier_block *me, unsigned long what,
279				void *ptr)
280{
281	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
282
283	switch (what) {
284	case NETDEV_REGISTER:
285		if (dev->type == ARPHRD_PHONET)
286			phonet_device_autoconf(dev);
287		break;
288	case NETDEV_UNREGISTER:
289		phonet_device_destroy(dev);
290		phonet_route_autodel(dev);
291		break;
292	}
293	return 0;
294
295}
296
297static struct notifier_block phonet_device_notifier = {
298	.notifier_call = phonet_device_notify,
299	.priority = 0,
300};
301
302/* Per-namespace Phonet devices handling */
303static int __net_init phonet_init_net(struct net *net)
304{
305	struct phonet_net *pnn = phonet_pernet(net);
306
307	if (!proc_create_net("phonet", 0, net->proc_net, &pn_sock_seq_ops,
308			sizeof(struct seq_net_private)))
309		return -ENOMEM;
310
311	INIT_LIST_HEAD(&pnn->pndevs.list);
312	mutex_init(&pnn->pndevs.lock);
313	mutex_init(&pnn->routes.lock);
314	return 0;
315}
316
317static void __net_exit phonet_exit_net(struct net *net)
318{
319	struct phonet_net *pnn = phonet_pernet(net);
320
321	remove_proc_entry("phonet", net->proc_net);
322	WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
323}
324
325static struct pernet_operations phonet_net_ops = {
326	.init = phonet_init_net,
327	.exit = phonet_exit_net,
328	.id   = &phonet_net_id,
329	.size = sizeof(struct phonet_net),
330};
331
332/* Initialize Phonet devices list */
333int __init phonet_device_init(void)
334{
335	int err = register_pernet_subsys(&phonet_net_ops);
336	if (err)
337		return err;
338
339	proc_create_net("pnresource", 0, init_net.proc_net, &pn_res_seq_ops,
340			sizeof(struct seq_net_private));
341	register_netdevice_notifier(&phonet_device_notifier);
342	err = phonet_netlink_register();
343	if (err)
344		phonet_device_exit();
345	return err;
346}
347
348void phonet_device_exit(void)
349{
350	rtnl_unregister_all(PF_PHONET);
351	unregister_netdevice_notifier(&phonet_device_notifier);
352	unregister_pernet_subsys(&phonet_net_ops);
353	remove_proc_entry("pnresource", init_net.proc_net);
354}
355
356int phonet_route_add(struct net_device *dev, u8 daddr)
357{
358	struct phonet_net *pnn = phonet_pernet(dev_net(dev));
359	struct phonet_routes *routes = &pnn->routes;
360	int err = -EEXIST;
361
362	daddr = daddr >> 2;
363	mutex_lock(&routes->lock);
364	if (routes->table[daddr] == NULL) {
365		rcu_assign_pointer(routes->table[daddr], dev);
366		dev_hold(dev);
367		err = 0;
368	}
369	mutex_unlock(&routes->lock);
370	return err;
371}
372
373int phonet_route_del(struct net_device *dev, u8 daddr)
374{
375	struct phonet_net *pnn = phonet_pernet(dev_net(dev));
376	struct phonet_routes *routes = &pnn->routes;
377
378	daddr = daddr >> 2;
379	mutex_lock(&routes->lock);
380	if (rcu_access_pointer(routes->table[daddr]) == dev)
381		RCU_INIT_POINTER(routes->table[daddr], NULL);
382	else
383		dev = NULL;
384	mutex_unlock(&routes->lock);
385
386	if (!dev)
387		return -ENOENT;
388	synchronize_rcu();
389	dev_put(dev);
390	return 0;
391}
392
393struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
394{
395	struct phonet_net *pnn = phonet_pernet(net);
396	struct phonet_routes *routes = &pnn->routes;
397	struct net_device *dev;
398
399	daddr >>= 2;
400	dev = rcu_dereference(routes->table[daddr]);
401	return dev;
402}
403
404struct net_device *phonet_route_output(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	rcu_read_lock();
412	dev = rcu_dereference(routes->table[daddr]);
413	dev_hold(dev);
414	rcu_read_unlock();
415
416	if (!dev)
417		dev = phonet_device_get(net); /* Default route */
418	return dev;
419}
420