1 /* Copyright (c) 2013-2018, The Linux Foundation. All rights reserved.
3 * This program is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License version 2 and
5 * only version 2 as published by the Free Software Foundation.
7 * This program is distributed in the hope that it will be useful,
8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
10 * GNU General Public License for more details.
12 * RMNET configuration engine
17 #include <linux/module.h>
18 #include <linux/netlink.h>
19 #include <linux/netdevice.h>
20 #include "rmnet_config.h"
21 #include "rmnet_handlers.h"
22 #include "rmnet_vnd.h"
23 #include "rmnet_private.h"
26 * The shared resource which needs to be protected is realdev->rx_handler_data.
27 * For the writer path, this is using rtnl_lock(). The writer paths are
28 * rmnet_newlink(), rmnet_dellink() and rmnet_force_unassociate_device(). These
29 * paths are already called with rtnl_lock() acquired in. There is also an
30 * ASSERT_RTNL() to ensure that we are calling with rtnl acquired. For
31 * dereference here, we will need to use rtnl_dereference(). Dev list writing
32 * needs to happen with rtnl_lock() acquired for netdev_master_upper_dev_link().
33 * For the reader path, the real_dev->rx_handler_data is called in the TX / RX
34 * path. We only need rcu_read_lock() for these scenarios. In these cases,
35 * the rcu_read_lock() is held in __dev_queue_xmit() and
36 * netif_receive_skb_internal(), so readers need to use rcu_dereference_rtnl()
37 * to get the relevant information. For dev list reading, we again acquire
38 * rcu_read_lock() in rmnet_dellink() for netdev_master_upper_dev_get_rcu().
39 * We also use unregister_netdevice_many() to free all rmnet devices in
40 * rmnet_force_unassociate_device() so we dont lose the rtnl_lock() and free in
44 /* Local Definitions and Declarations */
46 static const struct nla_policy rmnet_policy[IFLA_RMNET_MAX + 1] = {
47 [IFLA_RMNET_MUX_ID] = { .type = NLA_U16 },
48 [IFLA_RMNET_FLAGS] = { .len = sizeof(struct ifla_rmnet_flags) },
51 static int rmnet_is_real_dev_registered(const struct net_device *real_dev)
53 return rcu_access_pointer(real_dev->rx_handler) == rmnet_rx_handler;
57 static struct rmnet_port*
58 rmnet_get_port_rtnl(const struct net_device *real_dev)
60 return rtnl_dereference(real_dev->rx_handler_data);
63 static int rmnet_unregister_real_device(struct net_device *real_dev,
64 struct rmnet_port *port)
66 if (port->nr_rmnet_devs)
71 netdev_rx_handler_unregister(real_dev);
73 /* release reference on real_dev */
76 netdev_dbg(real_dev, "Removed from rmnet\n");
80 static int rmnet_register_real_device(struct net_device *real_dev)
82 struct rmnet_port *port;
87 if (rmnet_is_real_dev_registered(real_dev))
90 port = kzalloc(sizeof(*port), GFP_ATOMIC);
95 rc = netdev_rx_handler_register(real_dev, rmnet_rx_handler, port);
101 /* hold on to real dev for MAP data */
104 for (entry = 0; entry < RMNET_MAX_LOGICAL_EP; entry++)
105 INIT_HLIST_HEAD(&port->muxed_ep[entry]);
107 netdev_dbg(real_dev, "registered with rmnet\n");
111 static void rmnet_unregister_bridge(struct net_device *dev,
112 struct rmnet_port *port)
114 struct rmnet_port *bridge_port;
115 struct net_device *bridge_dev;
117 if (port->rmnet_mode != RMNET_EPMODE_BRIDGE)
120 /* bridge slave handling */
121 if (!port->nr_rmnet_devs) {
122 bridge_dev = port->bridge_ep;
124 bridge_port = rmnet_get_port_rtnl(bridge_dev);
125 bridge_port->bridge_ep = NULL;
126 bridge_port->rmnet_mode = RMNET_EPMODE_VND;
128 bridge_dev = port->bridge_ep;
130 bridge_port = rmnet_get_port_rtnl(bridge_dev);
131 rmnet_unregister_real_device(bridge_dev, bridge_port);
135 static int rmnet_newlink(struct net *src_net, struct net_device *dev,
136 struct nlattr *tb[], struct nlattr *data[],
137 struct netlink_ext_ack *extack)
139 u32 data_format = RMNET_FLAGS_INGRESS_DEAGGREGATION;
140 struct net_device *real_dev;
141 int mode = RMNET_EPMODE_VND;
142 struct rmnet_endpoint *ep;
143 struct rmnet_port *port;
147 real_dev = __dev_get_by_index(src_net, nla_get_u32(tb[IFLA_LINK]));
148 if (!real_dev || !dev)
151 if (!data[IFLA_RMNET_MUX_ID])
154 ep = kzalloc(sizeof(*ep), GFP_ATOMIC);
158 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
160 err = rmnet_register_real_device(real_dev);
164 port = rmnet_get_port_rtnl(real_dev);
165 err = rmnet_vnd_newlink(mux_id, dev, port, real_dev, ep);
169 port->rmnet_mode = mode;
171 hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
173 if (data[IFLA_RMNET_FLAGS]) {
174 struct ifla_rmnet_flags *flags;
176 flags = nla_data(data[IFLA_RMNET_FLAGS]);
177 data_format = flags->flags & flags->mask;
180 netdev_dbg(dev, "data format [0x%08X]\n", data_format);
181 port->data_format = data_format;
186 rmnet_unregister_real_device(real_dev, port);
192 static void rmnet_dellink(struct net_device *dev, struct list_head *head)
194 struct rmnet_priv *priv = netdev_priv(dev);
195 struct net_device *real_dev;
196 struct rmnet_endpoint *ep;
197 struct rmnet_port *port;
200 real_dev = priv->real_dev;
202 if (!real_dev || !rmnet_is_real_dev_registered(real_dev))
205 port = rmnet_get_port_rtnl(real_dev);
207 mux_id = rmnet_vnd_get_mux(dev);
209 ep = rmnet_get_endpoint(port, mux_id);
211 hlist_del_init_rcu(&ep->hlnode);
212 rmnet_unregister_bridge(dev, port);
213 rmnet_vnd_dellink(mux_id, port, ep);
216 rmnet_unregister_real_device(real_dev, port);
218 unregister_netdevice_queue(dev, head);
221 static void rmnet_force_unassociate_device(struct net_device *dev)
223 struct net_device *real_dev = dev;
224 struct hlist_node *tmp_ep;
225 struct rmnet_endpoint *ep;
226 struct rmnet_port *port;
227 unsigned long bkt_ep;
230 if (!rmnet_is_real_dev_registered(real_dev))
235 port = rmnet_get_port_rtnl(dev);
238 rmnet_unregister_bridge(dev, port);
240 hash_for_each_safe(port->muxed_ep, bkt_ep, tmp_ep, ep, hlnode) {
241 unregister_netdevice_queue(ep->egress_dev, &list);
242 rmnet_vnd_dellink(ep->mux_id, port, ep);
244 hlist_del_init_rcu(&ep->hlnode);
249 unregister_netdevice_many(&list);
251 rmnet_unregister_real_device(real_dev, port);
254 static int rmnet_config_notify_cb(struct notifier_block *nb,
255 unsigned long event, void *data)
257 struct net_device *dev = netdev_notifier_info_to_dev(data);
263 case NETDEV_UNREGISTER:
264 netdev_dbg(dev, "Kernel unregister\n");
265 rmnet_force_unassociate_device(dev);
275 static struct notifier_block rmnet_dev_notifier __read_mostly = {
276 .notifier_call = rmnet_config_notify_cb,
279 static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
280 struct netlink_ext_ack *extack)
284 if (!data || !data[IFLA_RMNET_MUX_ID])
287 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
288 if (mux_id > (RMNET_MAX_LOGICAL_EP - 1))
294 static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
295 struct nlattr *data[],
296 struct netlink_ext_ack *extack)
298 struct rmnet_priv *priv = netdev_priv(dev);
299 struct net_device *real_dev;
300 struct rmnet_endpoint *ep;
301 struct rmnet_port *port;
304 real_dev = __dev_get_by_index(dev_net(dev),
305 nla_get_u32(tb[IFLA_LINK]));
307 if (!real_dev || !dev || !rmnet_is_real_dev_registered(real_dev))
310 port = rmnet_get_port_rtnl(real_dev);
312 if (data[IFLA_RMNET_MUX_ID]) {
313 mux_id = nla_get_u16(data[IFLA_RMNET_MUX_ID]);
314 ep = rmnet_get_endpoint(port, priv->mux_id);
318 hlist_del_init_rcu(&ep->hlnode);
319 hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
322 priv->mux_id = mux_id;
325 if (data[IFLA_RMNET_FLAGS]) {
326 struct ifla_rmnet_flags *flags;
328 flags = nla_data(data[IFLA_RMNET_FLAGS]);
329 port->data_format = flags->flags & flags->mask;
335 static size_t rmnet_get_size(const struct net_device *dev)
338 /* IFLA_RMNET_MUX_ID */
340 /* IFLA_RMNET_FLAGS */
341 nla_total_size(sizeof(struct ifla_rmnet_flags));
344 static int rmnet_fill_info(struct sk_buff *skb, const struct net_device *dev)
346 struct rmnet_priv *priv = netdev_priv(dev);
347 struct net_device *real_dev;
348 struct ifla_rmnet_flags f;
349 struct rmnet_port *port;
351 real_dev = priv->real_dev;
353 if (nla_put_u16(skb, IFLA_RMNET_MUX_ID, priv->mux_id))
354 goto nla_put_failure;
356 if (rmnet_is_real_dev_registered(real_dev)) {
357 port = rmnet_get_port_rtnl(real_dev);
358 f.flags = port->data_format;
365 if (nla_put(skb, IFLA_RMNET_FLAGS, sizeof(f), &f))
366 goto nla_put_failure;
374 struct rtnl_link_ops rmnet_link_ops __read_mostly = {
376 .maxtype = __IFLA_RMNET_MAX,
377 .priv_size = sizeof(struct rmnet_priv),
378 .setup = rmnet_vnd_setup,
379 .validate = rmnet_rtnl_validate,
380 .newlink = rmnet_newlink,
381 .dellink = rmnet_dellink,
382 .get_size = rmnet_get_size,
383 .changelink = rmnet_changelink,
384 .policy = rmnet_policy,
385 .fill_info = rmnet_fill_info,
388 /* Needs either rcu_read_lock() or rtnl lock */
389 struct rmnet_port *rmnet_get_port(struct net_device *real_dev)
391 if (rmnet_is_real_dev_registered(real_dev))
392 return rcu_dereference_rtnl(real_dev->rx_handler_data);
397 struct rmnet_endpoint *rmnet_get_endpoint(struct rmnet_port *port, u8 mux_id)
399 struct rmnet_endpoint *ep;
401 hlist_for_each_entry_rcu(ep, &port->muxed_ep[mux_id], hlnode) {
402 if (ep->mux_id == mux_id)
409 int rmnet_add_bridge(struct net_device *rmnet_dev,
410 struct net_device *slave_dev,
411 struct netlink_ext_ack *extack)
413 struct rmnet_priv *priv = netdev_priv(rmnet_dev);
414 struct net_device *real_dev = priv->real_dev;
415 struct rmnet_port *port, *slave_port;
418 port = rmnet_get_port(real_dev);
420 /* If there is more than one rmnet dev attached, its probably being
421 * used for muxing. Skip the briding in that case
423 if (port->nr_rmnet_devs > 1)
426 if (rmnet_is_real_dev_registered(slave_dev))
429 err = rmnet_register_real_device(slave_dev);
433 slave_port = rmnet_get_port(slave_dev);
434 slave_port->rmnet_mode = RMNET_EPMODE_BRIDGE;
435 slave_port->bridge_ep = real_dev;
437 port->rmnet_mode = RMNET_EPMODE_BRIDGE;
438 port->bridge_ep = slave_dev;
440 netdev_dbg(slave_dev, "registered with rmnet as slave\n");
444 int rmnet_del_bridge(struct net_device *rmnet_dev,
445 struct net_device *slave_dev)
447 struct rmnet_priv *priv = netdev_priv(rmnet_dev);
448 struct net_device *real_dev = priv->real_dev;
449 struct rmnet_port *port, *slave_port;
451 port = rmnet_get_port(real_dev);
452 port->rmnet_mode = RMNET_EPMODE_VND;
453 port->bridge_ep = NULL;
455 slave_port = rmnet_get_port(slave_dev);
456 rmnet_unregister_real_device(slave_dev, slave_port);
458 netdev_dbg(slave_dev, "removed from rmnet as slave\n");
462 /* Startup/Shutdown */
464 static int __init rmnet_init(void)
468 rc = register_netdevice_notifier(&rmnet_dev_notifier);
472 rc = rtnl_link_register(&rmnet_link_ops);
474 unregister_netdevice_notifier(&rmnet_dev_notifier);
480 static void __exit rmnet_exit(void)
482 unregister_netdevice_notifier(&rmnet_dev_notifier);
483 rtnl_link_unregister(&rmnet_link_ops);
486 module_init(rmnet_init)
487 module_exit(rmnet_exit)
488 MODULE_LICENSE("GPL v2");