1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
3 *
4 * RMNET configuration engine
5 */
6
7 #include <net/sock.h>
8 #include <linux/module.h>
9 #include <linux/netlink.h>
10 #include <linux/netdevice.h>
11 #include "rmnet_config.h"
12 #include "rmnet_handlers.h"
13 #include "rmnet_vnd.h"
14 #include "rmnet_private.h"
15 #include "rmnet_map.h"
16
17 /* Local Definitions and Declarations */
18
19 static const struct nla_policy rmnet_policy[IFLA_RMNET_MAX + 1] = {
20 [IFLA_RMNET_MUX_ID] = { .type = NLA_U16 },
21 [IFLA_RMNET_FLAGS] = { .len = sizeof(struct ifla_rmnet_flags) },
22 };
23
rmnet_is_real_dev_registered(const struct net_device * real_dev)24 static int rmnet_is_real_dev_registered(const struct net_device *real_dev)
25 {
26 return rcu_access_pointer(real_dev->rx_handler) == rmnet_rx_handler;
27 }
28
29 /* Needs rtnl lock */
30 struct rmnet_port*
rmnet_get_port_rtnl(const struct net_device * real_dev)31 rmnet_get_port_rtnl(const struct net_device *real_dev)
32 {
33 return rtnl_dereference(real_dev->rx_handler_data);
34 }
35
rmnet_unregister_real_device(struct net_device * real_dev)36 static int rmnet_unregister_real_device(struct net_device *real_dev)
37 {
38 struct rmnet_port *port = rmnet_get_port_rtnl(real_dev);
39
40 if (port->nr_rmnet_devs)
41 return -EINVAL;
42
43 rmnet_map_tx_aggregate_exit(port);
44
45 netdev_rx_handler_unregister(real_dev);
46
47 kfree(port);
48
49 netdev_dbg(real_dev, "Removed from rmnet\n");
50 return 0;
51 }
52
rmnet_register_real_device(struct net_device * real_dev,struct netlink_ext_ack * extack)53 static int rmnet_register_real_device(struct net_device *real_dev,
54 struct netlink_ext_ack *extack)
55 {
56 struct rmnet_port *port;
57 int rc, entry;
58
59 ASSERT_RTNL();
60
61 if (rmnet_is_real_dev_registered(real_dev)) {
62 port = rmnet_get_port_rtnl(real_dev);
63 if (port->rmnet_mode != RMNET_EPMODE_VND) {
64 NL_SET_ERR_MSG_MOD(extack, "bridge device already exists");
65 return -EINVAL;
66 }
67
68 return 0;
69 }
70
71 port = kzalloc(sizeof(*port), GFP_KERNEL);
72 if (!port)
73 return -ENOMEM;
74
75 port->dev = real_dev;
76 rc = netdev_rx_handler_register(real_dev, rmnet_rx_handler, port);
77 if (rc) {
78 kfree(port);
79 return -EBUSY;
80 }
81
82 for (entry = 0; entry < RMNET_MAX_LOGICAL_EP; entry++)
83 INIT_HLIST_HEAD(&port->muxed_ep[entry]);
84
85 rmnet_map_tx_aggregate_init(port);
86
87 netdev_dbg(real_dev, "registered with rmnet\n");
88 return 0;
89 }
90
rmnet_unregister_bridge(struct rmnet_port * port)91 static void rmnet_unregister_bridge(struct rmnet_port *port)
92 {
93 struct net_device *bridge_dev, *real_dev, *rmnet_dev;
94 struct rmnet_port *real_port;
95
96 if (port->rmnet_mode != RMNET_EPMODE_BRIDGE)
97 return;
98
99 rmnet_dev = port->rmnet_dev;
100 if (!port->nr_rmnet_devs) {
101 /* bridge device */
102 real_dev = port->bridge_ep;
103 bridge_dev = port->dev;
104
105 real_port = rmnet_get_port_rtnl(real_dev);
106 real_port->bridge_ep = NULL;
107 real_port->rmnet_mode = RMNET_EPMODE_VND;
108 } else {
109 /* real device */
110 bridge_dev = port->bridge_ep;
111
112 port->bridge_ep = NULL;
113 port->rmnet_mode = RMNET_EPMODE_VND;
114 }
115
116 netdev_upper_dev_unlink(bridge_dev, rmnet_dev);
117 rmnet_unregister_real_device(bridge_dev);
118 }
119
rmnet_newlink(struct net * src_net,struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)120 static int rmnet_newlink(struct net *src_net, struct net_device *dev,
121 struct nlattr *tb[], struct nlattr *data[],
122 struct netlink_ext_ack *extack)
123 {
124 u32 data_format = RMNET_FLAGS_INGRESS_DEAGGREGATION;
125 struct net_device *real_dev;
126 int mode = RMNET_EPMODE_VND;
127 struct rmnet_endpoint *ep;
128 struct rmnet_port *port;
129 int err = 0;
130 u16 mux_id;
131
132 if (!tb[IFLA_LINK]) {
133 NL_SET_ERR_MSG_MOD(extack, "link not specified");
134 return -EINVAL;
135 }
136
137 real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
138 if (!real_dev) {
139 NL_SET_ERR_MSG_MOD(extack, "link does not exist");
140 return -ENODEV;
141 }
142
143 ep = kzalloc(sizeof(*ep), GFP_KERNEL);
144 if (!ep)
145 return -ENOMEM;
146
147 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
148
149 err = rmnet_register_real_device(real_dev, extack);
150 if (err)
151 goto err0;
152
153 port = rmnet_get_port_rtnl(real_dev);
154 err = rmnet_vnd_newlink(mux_id, dev, port, real_dev, ep, extack);
155 if (err)
156 goto err1;
157
158 err = netdev_upper_dev_link(real_dev, dev, extack);
159 if (err < 0)
160 goto err2;
161
162 port->rmnet_mode = mode;
163 port->rmnet_dev = dev;
164
165 hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
166
167 if (data[IFLA_RMNET_FLAGS]) {
168 struct ifla_rmnet_flags *flags;
169
170 flags = nla_data(data[IFLA_RMNET_FLAGS]);
171 data_format &= ~flags->mask;
172 data_format |= flags->flags & flags->mask;
173 }
174
175 netdev_dbg(dev, "data format [0x%08X]\n", data_format);
176 port->data_format = data_format;
177
178 return 0;
179
180 err2:
181 unregister_netdevice(dev);
182 rmnet_vnd_dellink(mux_id, port, ep);
183 err1:
184 rmnet_unregister_real_device(real_dev);
185 err0:
186 kfree(ep);
187 return err;
188 }
189
rmnet_dellink(struct net_device * dev,struct list_head * head)190 static void rmnet_dellink(struct net_device *dev, struct list_head *head)
191 {
192 struct rmnet_priv *priv = netdev_priv(dev);
193 struct net_device *real_dev, *bridge_dev;
194 struct rmnet_port *real_port, *bridge_port;
195 struct rmnet_endpoint *ep;
196 u8 mux_id = priv->mux_id;
197
198 real_dev = priv->real_dev;
199
200 if (!rmnet_is_real_dev_registered(real_dev))
201 return;
202
203 real_port = rmnet_get_port_rtnl(real_dev);
204 bridge_dev = real_port->bridge_ep;
205 if (bridge_dev) {
206 bridge_port = rmnet_get_port_rtnl(bridge_dev);
207 rmnet_unregister_bridge(bridge_port);
208 }
209
210 ep = rmnet_get_endpoint(real_port, mux_id);
211 if (ep) {
212 hlist_del_init_rcu(&ep->hlnode);
213 rmnet_vnd_dellink(mux_id, real_port, ep);
214 kfree(ep);
215 }
216
217 netdev_upper_dev_unlink(real_dev, dev);
218 rmnet_unregister_real_device(real_dev);
219 unregister_netdevice_queue(dev, head);
220 }
221
rmnet_force_unassociate_device(struct net_device * real_dev)222 static void rmnet_force_unassociate_device(struct net_device *real_dev)
223 {
224 struct hlist_node *tmp_ep;
225 struct rmnet_endpoint *ep;
226 struct rmnet_port *port;
227 unsigned long bkt_ep;
228 LIST_HEAD(list);
229
230 port = rmnet_get_port_rtnl(real_dev);
231
232 if (port->nr_rmnet_devs) {
233 /* real device */
234 rmnet_unregister_bridge(port);
235 hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
236 unregister_netdevice_queue(ep->egress_dev, &list);
237 netdev_upper_dev_unlink(real_dev, ep->egress_dev);
238 rmnet_vnd_dellink(ep->mux_id, port, ep);
239 hlist_del_init_rcu(&ep->hlnode);
240 kfree(ep);
241 }
242 rmnet_unregister_real_device(real_dev);
243 unregister_netdevice_many(&list);
244 } else {
245 rmnet_unregister_bridge(port);
246 }
247 }
248
rmnet_config_notify_cb(struct notifier_block * nb,unsigned long event,void * data)249 static int rmnet_config_notify_cb(struct notifier_block *nb,
250 unsigned long event, void *data)
251 {
252 struct net_device *real_dev = netdev_notifier_info_to_dev(data);
253
254 if (!rmnet_is_real_dev_registered(real_dev))
255 return NOTIFY_DONE;
256
257 switch (event) {
258 case NETDEV_UNREGISTER:
259 netdev_dbg(real_dev, "Kernel unregister\n");
260 rmnet_force_unassociate_device(real_dev);
261 break;
262 case NETDEV_CHANGEMTU:
263 if (rmnet_vnd_validate_real_dev_mtu(real_dev))
264 return NOTIFY_BAD;
265 break;
266 default:
267 break;
268 }
269
270 return NOTIFY_DONE;
271 }
272
273 static struct notifier_block rmnet_dev_notifier __read_mostly = {
274 .notifier_call = rmnet_config_notify_cb,
275 };
276
rmnet_rtnl_validate(struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)277 static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
278 struct netlink_ext_ack *extack)
279 {
280 u16 mux_id;
281
282 if (!data || !data[IFLA_RMNET_MUX_ID]) {
283 NL_SET_ERR_MSG_MOD(extack, "MUX ID not specified");
284 return -EINVAL;
285 }
286
287 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
288 if (mux_id > (RMNET_MAX_LOGICAL_EP - 1)) {
289 NL_SET_ERR_MSG_MOD(extack, "invalid MUX ID");
290 return -ERANGE;
291 }
292
293 return 0;
294 }
295
rmnet_changelink(struct net_device * dev,struct nlattr * tb[],struct nlattr * data[],struct netlink_ext_ack * extack)296 static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
297 struct nlattr *data[],
298 struct netlink_ext_ack *extack)
299 {
300 struct rmnet_priv *priv = netdev_priv(dev);
301 struct net_device *real_dev;
302 struct rmnet_port *port;
303 u16 mux_id;
304
305 if (!dev)
306 return -ENODEV;
307
308 real_dev = priv->real_dev;
309 if (!rmnet_is_real_dev_registered(real_dev))
310 return -ENODEV;
311
312 port = rmnet_get_port_rtnl(real_dev);
313
314 if (data[IFLA_RMNET_MUX_ID]) {
315 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
316
317 if (mux_id != priv->mux_id) {
318 struct rmnet_endpoint *ep;
319
320 ep = rmnet_get_endpoint(port, priv->mux_id);
321 if (!ep)
322 return -ENODEV;
323
324 if (rmnet_get_endpoint(port, mux_id)) {
325 NL_SET_ERR_MSG_MOD(extack,
326 "MUX ID already exists");
327 return -EINVAL;
328 }
329
330 hlist_del_init_rcu(&ep->hlnode);
331 hlist_add_head_rcu(&ep->hlnode,
332 &port->muxed_ep[mux_id]);
333
334 ep->mux_id = mux_id;
335 priv->mux_id = mux_id;
336 }
337 }
338
339 if (data[IFLA_RMNET_FLAGS]) {
340 struct ifla_rmnet_flags *flags;
341 u32 old_data_format;
342
343 old_data_format = port->data_format;
344 flags = nla_data(data[IFLA_RMNET_FLAGS]);
345 port->data_format &= ~flags->mask;
346 port->data_format |= flags->flags & flags->mask;
347
348 if (rmnet_vnd_update_dev_mtu(port, real_dev)) {
349 port->data_format = old_data_format;
350 NL_SET_ERR_MSG_MOD(extack, "Invalid MTU on real dev");
351 return -EINVAL;
352 }
353 }
354
355 return 0;
356 }
357
rmnet_get_size(const struct net_device * dev)358 static size_t rmnet_get_size(const struct net_device *dev)
359 {
360 return
361 /* IFLA_RMNET_MUX_ID */
362 nla_total_size(2) +
363 /* IFLA_RMNET_FLAGS */
364 nla_total_size(sizeof(struct ifla_rmnet_flags));
365 }
366
rmnet_fill_info(struct sk_buff * skb,const struct net_device * dev)367 static int rmnet_fill_info(struct sk_buff *skb, const struct net_device *dev)
368 {
369 struct rmnet_priv *priv = netdev_priv(dev);
370 struct net_device *real_dev;
371 struct ifla_rmnet_flags f;
372 struct rmnet_port *port;
373
374 real_dev = priv->real_dev;
375
376 if (nla_put_u16(skb, IFLA_RMNET_MUX_ID, priv->mux_id))
377 goto nla_put_failure;
378
379 if (rmnet_is_real_dev_registered(real_dev)) {
380 port = rmnet_get_port_rtnl(real_dev);
381 f.flags = port->data_format;
382 } else {
383 f.flags = 0;
384 }
385
386 f.mask = ~0;
387
388 if (nla_put(skb, IFLA_RMNET_FLAGS, sizeof(f), &f))
389 goto nla_put_failure;
390
391 return 0;
392
393 nla_put_failure:
394 return -EMSGSIZE;
395 }
396
397 struct rtnl_link_ops rmnet_link_ops __read_mostly = {
398 .kind = "rmnet",
399 .maxtype = IFLA_RMNET_MAX,
400 .priv_size = sizeof(struct rmnet_priv),
401 .setup = rmnet_vnd_setup,
402 .validate = rmnet_rtnl_validate,
403 .newlink = rmnet_newlink,
404 .dellink = rmnet_dellink,
405 .get_size = rmnet_get_size,
406 .changelink = rmnet_changelink,
407 .policy = rmnet_policy,
408 .fill_info = rmnet_fill_info,
409 };
410
rmnet_get_port_rcu(struct net_device * real_dev)411 struct rmnet_port *rmnet_get_port_rcu(struct net_device *real_dev)
412 {
413 if (rmnet_is_real_dev_registered(real_dev))
414 return rcu_dereference_bh(real_dev->rx_handler_data);
415 else
416 return NULL;
417 }
418
rmnet_get_endpoint(struct rmnet_port * port,u8 mux_id)419 struct rmnet_endpoint *rmnet_get_endpoint(struct rmnet_port *port, u8 mux_id)
420 {
421 struct rmnet_endpoint *ep;
422
423 hlist_for_each_entry_rcu(ep, &port->muxed_ep[mux_id], hlnode) {
424 if (ep->mux_id == mux_id)
425 return ep;
426 }
427
428 return NULL;
429 }
430
rmnet_add_bridge(struct net_device * rmnet_dev,struct net_device * slave_dev,struct netlink_ext_ack * extack)431 int rmnet_add_bridge(struct net_device *rmnet_dev,
432 struct net_device *slave_dev,
433 struct netlink_ext_ack *extack)
434 {
435 struct rmnet_priv *priv = netdev_priv(rmnet_dev);
436 struct net_device *real_dev = priv->real_dev;
437 struct rmnet_port *port, *slave_port;
438 int err;
439
440 port = rmnet_get_port_rtnl(real_dev);
441
442 /* If there is more than one rmnet dev attached, its probably being
443 * used for muxing. Skip the briding in that case
444 */
445 if (port->nr_rmnet_devs > 1) {
446 NL_SET_ERR_MSG_MOD(extack, "more than one rmnet dev attached");
447 return -EINVAL;
448 }
449
450 if (port->rmnet_mode != RMNET_EPMODE_VND) {
451 NL_SET_ERR_MSG_MOD(extack, "more than one bridge dev attached");
452 return -EINVAL;
453 }
454
455 if (rmnet_is_real_dev_registered(slave_dev)) {
456 NL_SET_ERR_MSG_MOD(extack,
457 "slave cannot be another rmnet dev");
458
459 return -EBUSY;
460 }
461
462 err = rmnet_register_real_device(slave_dev, extack);
463 if (err)
464 return -EBUSY;
465
466 err = netdev_master_upper_dev_link(slave_dev, rmnet_dev, NULL, NULL,
467 extack);
468 if (err) {
469 rmnet_unregister_real_device(slave_dev);
470 return err;
471 }
472
473 slave_port = rmnet_get_port_rtnl(slave_dev);
474 slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE;
475 slave_port->bridge_ep = real_dev;
476 slave_port->rmnet_dev = rmnet_dev;
477
478 port->rmnet_mode = RMNET_EPMODE_BRIDGE;
479 port->bridge_ep = slave_dev;
480
481 netdev_dbg(slave_dev, "registered with rmnet as slave\n");
482 return 0;
483 }
484
rmnet_del_bridge(struct net_device * rmnet_dev,struct net_device * slave_dev)485 int rmnet_del_bridge(struct net_device *rmnet_dev,
486 struct net_device *slave_dev)
487 {
488 struct rmnet_port *port = rmnet_get_port_rtnl(slave_dev);
489
490 rmnet_unregister_bridge(port);
491
492 netdev_dbg(slave_dev, "removed from rmnet as slave\n");
493 return 0;
494 }
495
496 /* Startup/Shutdown */
497
rmnet_init(void)498 static int __init rmnet_init(void)
499 {
500 int rc;
501
502 rc = register_netdevice_notifier(&rmnet_dev_notifier);
503 if (rc != 0)
504 return rc;
505
506 rc = rtnl_link_register(&rmnet_link_ops);
507 if (rc != 0) {
508 unregister_netdevice_notifier(&rmnet_dev_notifier);
509 return rc;
510 }
511 return rc;
512 }
513
rmnet_exit(void)514 static void __exit rmnet_exit(void)
515 {
516 rtnl_link_unregister(&rmnet_link_ops);
517 unregister_netdevice_notifier(&rmnet_dev_notifier);
518 }
519
520 module_init(rmnet_init)
521 module_exit(rmnet_exit)
522 MODULE_ALIAS_RTNL_LINK("rmnet");
523 MODULE_LICENSE("GPL v2");
524