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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 <[email protected]>
10 * Rémi 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 spinlock_t 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_obj(*pnd, GFP_ATOMIC);
52 if (pnd == NULL)
53 return NULL;
54 pnd->netdev = dev;
55 bitmap_zero(pnd->addrs, 64);
56
57 lockdep_assert_held(&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 lockdep_assert_held(&pndevs->lock);
68
69 list_for_each_entry(pnd, &pndevs->list, list) {
70 if (pnd->netdev == dev)
71 return pnd;
72 }
73 return NULL;
74}
75
76static struct phonet_device *__phonet_get_rcu(struct net_device *dev)
77{
78 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
79 struct phonet_device *pnd;
80
81 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
82 if (pnd->netdev == dev)
83 return pnd;
84 }
85 return NULL;
86}
87
88static void phonet_device_destroy(struct net_device *dev)
89{
90 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
91 struct phonet_device *pnd;
92
93 ASSERT_RTNL();
94
95 spin_lock(&pndevs->lock);
96
97 pnd = __phonet_get(dev);
98 if (pnd)
99 list_del_rcu(&pnd->list);
100
101 spin_unlock(&pndevs->lock);
102
103 if (pnd) {
104 struct net *net = dev_net(dev);
105 u32 ifindex = dev->ifindex;
106 u8 addr;
107
108 for_each_set_bit(addr, pnd->addrs, 64)
109 phonet_address_notify(net, RTM_DELADDR, ifindex, addr);
110
111 kfree_rcu(pnd, rcu);
112 }
113}
114
115struct net_device *phonet_device_get(struct net *net)
116{
117 struct phonet_device_list *pndevs = phonet_device_list(net);
118 struct phonet_device *pnd;
119 struct net_device *dev = NULL;
120
121 rcu_read_lock();
122 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
123 dev = pnd->netdev;
124 BUG_ON(!dev);
125
126 if ((dev->reg_state == NETREG_REGISTERED) &&
127 ((pnd->netdev->flags & IFF_UP)) == IFF_UP)
128 break;
129 dev = NULL;
130 }
131 dev_hold(dev);
132 rcu_read_unlock();
133 return dev;
134}
135
136int phonet_address_add(struct net_device *dev, u8 addr)
137{
138 struct phonet_device_list *pndevs = phonet_device_list(dev_net(dev));
139 struct phonet_device *pnd;
140 int err = 0;
141
142 spin_lock(&pndevs->lock);
143
144 /* Find or create Phonet-specific device data */
145 pnd = __phonet_get(dev);
146 if (pnd == NULL)
147 pnd = __phonet_device_alloc(dev);
148 if (unlikely(pnd == NULL))
149 err = -ENOMEM;
150 else if (test_and_set_bit(addr >> 2, pnd->addrs))
151 err = -EEXIST;
152
153 spin_unlock(&pndevs->lock);
154
155 return err;
156}
157
158int 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 spin_lock(&pndevs->lock);
165
166 pnd = __phonet_get(dev);
167 if (!pnd || !test_and_clear_bit(addr >> 2, pnd->addrs)) {
168 err = -EADDRNOTAVAIL;
169 pnd = NULL;
170 } else if (bitmap_empty(pnd->addrs, 64))
171 list_del_rcu(&pnd->list);
172 else
173 pnd = NULL;
174
175 spin_unlock(&pndevs->lock);
176
177 if (pnd)
178 kfree_rcu(pnd, rcu);
179
180 return err;
181}
182
183/* Gets a source address toward a destination, through a interface. */
184u8 phonet_address_get(struct net_device *dev, u8 daddr)
185{
186 struct phonet_device *pnd;
187 u8 saddr;
188
189 rcu_read_lock();
190 pnd = __phonet_get_rcu(dev);
191 if (pnd) {
192 BUG_ON(bitmap_empty(pnd->addrs, 64));
193
194 /* Use same source address as destination, if possible */
195 if (test_bit(daddr >> 2, pnd->addrs))
196 saddr = daddr;
197 else
198 saddr = find_first_bit(pnd->addrs, 64) << 2;
199 } else
200 saddr = PN_NO_ADDR;
201 rcu_read_unlock();
202
203 if (saddr == PN_NO_ADDR) {
204 /* Fallback to another device */
205 struct net_device *def_dev;
206
207 def_dev = phonet_device_get(dev_net(dev));
208 if (def_dev) {
209 if (def_dev != dev)
210 saddr = phonet_address_get(def_dev, daddr);
211 dev_put(def_dev);
212 }
213 }
214 return saddr;
215}
216
217int phonet_address_lookup(struct net *net, u8 addr)
218{
219 struct phonet_device_list *pndevs = phonet_device_list(net);
220 struct phonet_device *pnd;
221 int err = -EADDRNOTAVAIL;
222
223 rcu_read_lock();
224 list_for_each_entry_rcu(pnd, &pndevs->list, list) {
225 /* Don't allow unregistering devices! */
226 if ((pnd->netdev->reg_state != NETREG_REGISTERED) ||
227 ((pnd->netdev->flags & IFF_UP)) != IFF_UP)
228 continue;
229
230 if (test_bit(addr >> 2, pnd->addrs)) {
231 err = 0;
232 goto found;
233 }
234 }
235found:
236 rcu_read_unlock();
237 return err;
238}
239
240/* automatically configure a Phonet device, if supported */
241static int phonet_device_autoconf(struct net_device *dev)
242{
243 struct if_phonet_req req;
244 int ret;
245
246 if (!dev->netdev_ops->ndo_siocdevprivate)
247 return -EOPNOTSUPP;
248
249 ret = dev->netdev_ops->ndo_siocdevprivate(dev, (struct ifreq *)&req,
250 NULL, SIOCPNGAUTOCONF);
251 if (ret < 0)
252 return ret;
253
254 ASSERT_RTNL();
255 ret = phonet_address_add(dev, req.ifr_phonet_autoconf.device);
256 if (ret)
257 return ret;
258
259 phonet_address_notify(dev_net(dev), RTM_NEWADDR, dev->ifindex,
260 req.ifr_phonet_autoconf.device);
261 return 0;
262}
263
264static void phonet_route_autodel(struct net_device *dev)
265{
266 struct net *net = dev_net(dev);
267 DECLARE_BITMAP(deleted, 64);
268 u32 ifindex = dev->ifindex;
269 struct phonet_net *pnn;
270 unsigned int i;
271
272 pnn = phonet_pernet(net);
273
274 /* Remove left-over Phonet routes */
275 bitmap_zero(deleted, 64);
276
277 spin_lock(&pnn->routes.lock);
278 for (i = 0; i < 64; i++) {
279 if (rcu_access_pointer(pnn->routes.table[i]) == dev) {
280 RCU_INIT_POINTER(pnn->routes.table[i], NULL);
281 set_bit(i, deleted);
282 }
283 }
284 spin_unlock(&pnn->routes.lock);
285
286 if (bitmap_empty(deleted, 64))
287 return; /* short-circuit RCU */
288 synchronize_rcu();
289 for_each_set_bit(i, deleted, 64) {
290 rtm_phonet_notify(net, RTM_DELROUTE, ifindex, i);
291 dev_put(dev);
292 }
293}
294
295/* notify Phonet of device events */
296static int phonet_device_notify(struct notifier_block *me, unsigned long what,
297 void *ptr)
298{
299 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
300
301 switch (what) {
302 case NETDEV_REGISTER:
303 if (dev->type == ARPHRD_PHONET)
304 phonet_device_autoconf(dev);
305 break;
306 case NETDEV_UNREGISTER:
307 phonet_device_destroy(dev);
308 phonet_route_autodel(dev);
309 break;
310 }
311 return 0;
312
313}
314
315static struct notifier_block phonet_device_notifier = {
316 .notifier_call = phonet_device_notify,
317 .priority = 0,
318};
319
320/* Per-namespace Phonet devices handling */
321static int __net_init phonet_init_net(struct net *net)
322{
323 struct phonet_net *pnn = phonet_pernet(net);
324
325 if (!proc_create_net("phonet", 0, net->proc_net, &pn_sock_seq_ops,
326 sizeof(struct seq_net_private)))
327 return -ENOMEM;
328
329 INIT_LIST_HEAD(&pnn->pndevs.list);
330 spin_lock_init(&pnn->pndevs.lock);
331 spin_lock_init(&pnn->routes.lock);
332 return 0;
333}
334
335static void __net_exit phonet_exit_net(struct net *net)
336{
337 struct phonet_net *pnn = phonet_pernet(net);
338
339 remove_proc_entry("phonet", net->proc_net);
340 WARN_ON_ONCE(!list_empty(&pnn->pndevs.list));
341}
342
343static struct pernet_operations phonet_net_ops = {
344 .init = phonet_init_net,
345 .exit = phonet_exit_net,
346 .id = &phonet_net_id,
347 .size = sizeof(struct phonet_net),
348};
349
350/* Initialize Phonet devices list */
351int __init phonet_device_init(void)
352{
353 int err;
354
355 err = register_pernet_subsys(&phonet_net_ops);
356 if (err)
357 return err;
358
359 if (!proc_create_net("pnresource", 0, init_net.proc_net,
360 &pn_res_seq_ops, sizeof(struct seq_net_private))) {
361 err = -ENOMEM;
362 goto err_pernet;
363 }
364
365 err = register_netdevice_notifier(&phonet_device_notifier);
366 if (err)
367 goto err_proc;
368
369 err = phonet_netlink_register();
370 if (err)
371 goto err_notifier;
372
373 return 0;
374
375err_notifier:
376 unregister_netdevice_notifier(&phonet_device_notifier);
377err_proc:
378 remove_proc_entry("pnresource", init_net.proc_net);
379err_pernet:
380 unregister_pernet_subsys(&phonet_net_ops);
381 return err;
382}
383
384void phonet_device_exit(void)
385{
386 rtnl_unregister_all(PF_PHONET);
387 unregister_netdevice_notifier(&phonet_device_notifier);
388 remove_proc_entry("pnresource", init_net.proc_net);
389 unregister_pernet_subsys(&phonet_net_ops);
390}
391
392int 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
400 spin_lock(&routes->lock);
401 if (routes->table[daddr] == NULL) {
402 rcu_assign_pointer(routes->table[daddr], dev);
403 dev_hold(dev);
404 err = 0;
405 }
406 spin_unlock(&routes->lock);
407
408 return err;
409}
410
411int phonet_route_del(struct net_device *dev, u8 daddr)
412{
413 struct phonet_net *pnn = phonet_pernet(dev_net(dev));
414 struct phonet_routes *routes = &pnn->routes;
415
416 daddr = daddr >> 2;
417
418 spin_lock(&routes->lock);
419 if (rcu_access_pointer(routes->table[daddr]) == dev)
420 RCU_INIT_POINTER(routes->table[daddr], NULL);
421 else
422 dev = NULL;
423 spin_unlock(&routes->lock);
424
425 if (!dev)
426 return -ENOENT;
427
428 /* Note : our caller must call synchronize_rcu() and dev_put(dev) */
429
430 return 0;
431}
432
433struct net_device *phonet_route_get_rcu(struct net *net, u8 daddr)
434{
435 struct phonet_net *pnn = phonet_pernet(net);
436 struct phonet_routes *routes = &pnn->routes;
437 struct net_device *dev;
438
439 daddr >>= 2;
440 dev = rcu_dereference(routes->table[daddr]);
441 return dev;
442}
443
444struct 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 dev_hold(dev);
454 rcu_read_unlock();
455
456 if (!dev)
457 dev = phonet_device_get(net); /* Default route */
458 return dev;
459}