1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2018, Intel Corporation. */
3
4 /* A common module to handle registrations and notifications for paravirtual
5 * drivers to enable accelerated datapath and support VF live migration.
6 *
7 * The notifier and event handling code is based on netvsc driver.
8 */
9
10 #include <linux/module.h>
11 #include <linux/etherdevice.h>
12 #include <uapi/linux/if_arp.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/if_vlan.h>
15 #include <net/failover.h>
16
17 static LIST_HEAD(failover_list);
18 static DEFINE_SPINLOCK(failover_lock);
19
failover_get_bymac(u8 * mac,struct failover_ops ** ops)20 static struct net_device *failover_get_bymac(u8 *mac, struct failover_ops **ops)
21 {
22 struct net_device *failover_dev;
23 struct failover *failover;
24
25 spin_lock(&failover_lock);
26 list_for_each_entry(failover, &failover_list, list) {
27 failover_dev = rtnl_dereference(failover->failover_dev);
28 if (ether_addr_equal(failover_dev->perm_addr, mac)) {
29 *ops = rtnl_dereference(failover->ops);
30 spin_unlock(&failover_lock);
31 return failover_dev;
32 }
33 }
34 spin_unlock(&failover_lock);
35 return NULL;
36 }
37
38 /**
39 * failover_slave_register - Register a slave netdev
40 *
41 * @slave_dev: slave netdev that is being registered
42 *
43 * Registers a slave device to a failover instance. Only ethernet devices
44 * are supported.
45 */
failover_slave_register(struct net_device * slave_dev)46 static int failover_slave_register(struct net_device *slave_dev)
47 {
48 struct netdev_lag_upper_info lag_upper_info;
49 struct net_device *failover_dev;
50 struct failover_ops *fops;
51 int err;
52
53 if (slave_dev->type != ARPHRD_ETHER)
54 goto done;
55
56 ASSERT_RTNL();
57
58 failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
59 if (!failover_dev)
60 goto done;
61
62 if (fops && fops->slave_pre_register &&
63 fops->slave_pre_register(slave_dev, failover_dev))
64 goto done;
65
66 err = netdev_rx_handler_register(slave_dev, fops->slave_handle_frame,
67 failover_dev);
68 if (err) {
69 netdev_err(slave_dev, "can not register failover rx handler (err = %d)\n",
70 err);
71 goto done;
72 }
73
74 lag_upper_info.tx_type = NETDEV_LAG_TX_TYPE_ACTIVEBACKUP;
75 err = netdev_master_upper_dev_link(slave_dev, failover_dev, NULL,
76 &lag_upper_info, NULL);
77 if (err) {
78 netdev_err(slave_dev, "can not set failover device %s (err = %d)\n",
79 failover_dev->name, err);
80 goto err_upper_link;
81 }
82
83 slave_dev->priv_flags |= (IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
84
85 if (fops && fops->slave_register &&
86 !fops->slave_register(slave_dev, failover_dev))
87 return NOTIFY_OK;
88
89 netdev_upper_dev_unlink(slave_dev, failover_dev);
90 slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
91 err_upper_link:
92 netdev_rx_handler_unregister(slave_dev);
93 done:
94 return NOTIFY_DONE;
95 }
96
97 /**
98 * failover_slave_unregister - Unregister a slave netdev
99 *
100 * @slave_dev: slave netdev that is being unregistered
101 *
102 * Unregisters a slave device from a failover instance.
103 */
failover_slave_unregister(struct net_device * slave_dev)104 int failover_slave_unregister(struct net_device *slave_dev)
105 {
106 struct net_device *failover_dev;
107 struct failover_ops *fops;
108
109 if (!netif_is_failover_slave(slave_dev))
110 goto done;
111
112 ASSERT_RTNL();
113
114 failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
115 if (!failover_dev)
116 goto done;
117
118 if (fops && fops->slave_pre_unregister &&
119 fops->slave_pre_unregister(slave_dev, failover_dev))
120 goto done;
121
122 netdev_rx_handler_unregister(slave_dev);
123 netdev_upper_dev_unlink(slave_dev, failover_dev);
124 slave_dev->priv_flags &= ~(IFF_FAILOVER_SLAVE | IFF_NO_ADDRCONF);
125
126 if (fops && fops->slave_unregister &&
127 !fops->slave_unregister(slave_dev, failover_dev))
128 return NOTIFY_OK;
129
130 done:
131 return NOTIFY_DONE;
132 }
133 EXPORT_SYMBOL_GPL(failover_slave_unregister);
134
failover_slave_link_change(struct net_device * slave_dev)135 static int failover_slave_link_change(struct net_device *slave_dev)
136 {
137 struct net_device *failover_dev;
138 struct failover_ops *fops;
139
140 if (!netif_is_failover_slave(slave_dev))
141 goto done;
142
143 ASSERT_RTNL();
144
145 failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
146 if (!failover_dev)
147 goto done;
148
149 if (!netif_running(failover_dev))
150 goto done;
151
152 if (fops && fops->slave_link_change &&
153 !fops->slave_link_change(slave_dev, failover_dev))
154 return NOTIFY_OK;
155
156 done:
157 return NOTIFY_DONE;
158 }
159
failover_slave_name_change(struct net_device * slave_dev)160 static int failover_slave_name_change(struct net_device *slave_dev)
161 {
162 struct net_device *failover_dev;
163 struct failover_ops *fops;
164
165 if (!netif_is_failover_slave(slave_dev))
166 goto done;
167
168 ASSERT_RTNL();
169
170 failover_dev = failover_get_bymac(slave_dev->perm_addr, &fops);
171 if (!failover_dev)
172 goto done;
173
174 if (!netif_running(failover_dev))
175 goto done;
176
177 if (fops && fops->slave_name_change &&
178 !fops->slave_name_change(slave_dev, failover_dev))
179 return NOTIFY_OK;
180
181 done:
182 return NOTIFY_DONE;
183 }
184
185 static int
failover_event(struct notifier_block * this,unsigned long event,void * ptr)186 failover_event(struct notifier_block *this, unsigned long event, void *ptr)
187 {
188 struct net_device *event_dev = netdev_notifier_info_to_dev(ptr);
189
190 /* Skip parent events */
191 if (netif_is_failover(event_dev))
192 return NOTIFY_DONE;
193
194 switch (event) {
195 case NETDEV_REGISTER:
196 return failover_slave_register(event_dev);
197 case NETDEV_UNREGISTER:
198 return failover_slave_unregister(event_dev);
199 case NETDEV_UP:
200 case NETDEV_DOWN:
201 case NETDEV_CHANGE:
202 return failover_slave_link_change(event_dev);
203 case NETDEV_CHANGENAME:
204 return failover_slave_name_change(event_dev);
205 default:
206 return NOTIFY_DONE;
207 }
208 }
209
210 static struct notifier_block failover_notifier = {
211 .notifier_call = failover_event,
212 };
213
214 static void
failover_existing_slave_register(struct net_device * failover_dev)215 failover_existing_slave_register(struct net_device *failover_dev)
216 {
217 struct net *net = dev_net(failover_dev);
218 struct net_device *dev;
219
220 rtnl_lock();
221 for_each_netdev(net, dev) {
222 if (netif_is_failover(dev))
223 continue;
224 if (ether_addr_equal(failover_dev->perm_addr, dev->perm_addr))
225 failover_slave_register(dev);
226 }
227 rtnl_unlock();
228 }
229
230 /**
231 * failover_register - Register a failover instance
232 *
233 * @dev: failover netdev
234 * @ops: failover ops
235 *
236 * Allocate and register a failover instance for a failover netdev. ops
237 * provides handlers for slave device register/unregister/link change/
238 * name change events.
239 *
240 * Return: pointer to failover instance
241 */
failover_register(struct net_device * dev,struct failover_ops * ops)242 struct failover *failover_register(struct net_device *dev,
243 struct failover_ops *ops)
244 {
245 struct failover *failover;
246
247 if (dev->type != ARPHRD_ETHER)
248 return ERR_PTR(-EINVAL);
249
250 failover = kzalloc(sizeof(*failover), GFP_KERNEL);
251 if (!failover)
252 return ERR_PTR(-ENOMEM);
253
254 rcu_assign_pointer(failover->ops, ops);
255 netdev_hold(dev, &failover->dev_tracker, GFP_KERNEL);
256 dev->priv_flags |= IFF_FAILOVER;
257 rcu_assign_pointer(failover->failover_dev, dev);
258
259 spin_lock(&failover_lock);
260 list_add_tail(&failover->list, &failover_list);
261 spin_unlock(&failover_lock);
262
263 netdev_info(dev, "failover master:%s registered\n", dev->name);
264
265 failover_existing_slave_register(dev);
266
267 return failover;
268 }
269 EXPORT_SYMBOL_GPL(failover_register);
270
271 /**
272 * failover_unregister - Unregister a failover instance
273 *
274 * @failover: pointer to failover instance
275 *
276 * Unregisters and frees a failover instance.
277 */
failover_unregister(struct failover * failover)278 void failover_unregister(struct failover *failover)
279 {
280 struct net_device *failover_dev;
281
282 failover_dev = rcu_dereference(failover->failover_dev);
283
284 netdev_info(failover_dev, "failover master:%s unregistered\n",
285 failover_dev->name);
286
287 failover_dev->priv_flags &= ~IFF_FAILOVER;
288 netdev_put(failover_dev, &failover->dev_tracker);
289
290 spin_lock(&failover_lock);
291 list_del(&failover->list);
292 spin_unlock(&failover_lock);
293
294 kfree(failover);
295 }
296 EXPORT_SYMBOL_GPL(failover_unregister);
297
298 static __init int
failover_init(void)299 failover_init(void)
300 {
301 register_netdevice_notifier(&failover_notifier);
302
303 return 0;
304 }
305 module_init(failover_init);
306
307 static __exit
failover_exit(void)308 void failover_exit(void)
309 {
310 unregister_netdevice_notifier(&failover_notifier);
311 }
312 module_exit(failover_exit);
313
314 MODULE_DESCRIPTION("Generic failover infrastructure/interface");
315 MODULE_LICENSE("GPL v2");
316