Commit | Line | Data |
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2874c5fd | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
1da177e4 LT |
2 | /* |
3 | * Linux network device link state notification | |
4 | * | |
5 | * Author: | |
6 | * Stefan Rompf <sux@loplof.de> | |
1da177e4 LT |
7 | */ |
8 | ||
1da177e4 LT |
9 | #include <linux/module.h> |
10 | #include <linux/netdevice.h> | |
11 | #include <linux/if.h> | |
12 | #include <net/sock.h> | |
cacaddf5 | 13 | #include <net/pkt_sched.h> |
1da177e4 LT |
14 | #include <linux/rtnetlink.h> |
15 | #include <linux/jiffies.h> | |
16 | #include <linux/spinlock.h> | |
1da177e4 LT |
17 | #include <linux/workqueue.h> |
18 | #include <linux/bitops.h> | |
e56f7359 | 19 | #include <linux/types.h> |
1da177e4 | 20 | |
6264f58c | 21 | #include "dev.h" |
1da177e4 LT |
22 | |
23 | enum lw_bits { | |
d9568ba9 | 24 | LW_URGENT = 0, |
1da177e4 LT |
25 | }; |
26 | ||
27 | static unsigned long linkwatch_flags; | |
28 | static unsigned long linkwatch_nextevent; | |
29 | ||
65f27f38 DH |
30 | static void linkwatch_event(struct work_struct *dummy); |
31 | static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event); | |
1da177e4 | 32 | |
e014debe | 33 | static LIST_HEAD(lweventlist); |
1da177e4 LT |
34 | static DEFINE_SPINLOCK(lweventlist_lock); |
35 | ||
b00055aa SR |
36 | static unsigned char default_operstate(const struct net_device *dev) |
37 | { | |
eec517cd AL |
38 | if (netif_testing(dev)) |
39 | return IF_OPER_TESTING; | |
40 | ||
8c55face VO |
41 | /* Some uppers (DSA) have additional sources for being down, so |
42 | * first check whether lower is indeed the source of its down state. | |
43 | */ | |
44 | if (!netif_carrier_ok(dev)) { | |
45 | int iflink = dev_get_iflink(dev); | |
46 | struct net_device *peer; | |
47 | ||
48 | if (iflink == dev->ifindex) | |
49 | return IF_OPER_DOWN; | |
50 | ||
51 | peer = __dev_get_by_index(dev_net(dev), iflink); | |
52 | if (!peer) | |
53 | return IF_OPER_DOWN; | |
54 | ||
55 | return netif_carrier_ok(peer) ? IF_OPER_DOWN : | |
56 | IF_OPER_LOWERLAYERDOWN; | |
57 | } | |
b00055aa SR |
58 | |
59 | if (netif_dormant(dev)) | |
60 | return IF_OPER_DORMANT; | |
61 | ||
62 | return IF_OPER_UP; | |
63 | } | |
64 | ||
65 | ||
66 | static void rfc2863_policy(struct net_device *dev) | |
67 | { | |
68 | unsigned char operstate = default_operstate(dev); | |
69 | ||
70 | if (operstate == dev->operstate) | |
71 | return; | |
72 | ||
fd888e85 | 73 | write_lock(&dev_base_lock); |
b00055aa SR |
74 | |
75 | switch(dev->link_mode) { | |
eec517cd AL |
76 | case IF_LINK_MODE_TESTING: |
77 | if (operstate == IF_OPER_UP) | |
78 | operstate = IF_OPER_TESTING; | |
79 | break; | |
80 | ||
b00055aa SR |
81 | case IF_LINK_MODE_DORMANT: |
82 | if (operstate == IF_OPER_UP) | |
83 | operstate = IF_OPER_DORMANT; | |
84 | break; | |
b00055aa SR |
85 | case IF_LINK_MODE_DEFAULT: |
86 | default: | |
87 | break; | |
3ff50b79 | 88 | } |
b00055aa SR |
89 | |
90 | dev->operstate = operstate; | |
91 | ||
fd888e85 | 92 | write_unlock(&dev_base_lock); |
b00055aa SR |
93 | } |
94 | ||
95 | ||
8f4cccbb BH |
96 | void linkwatch_init_dev(struct net_device *dev) |
97 | { | |
98 | /* Handle pre-registration link state changes */ | |
eec517cd AL |
99 | if (!netif_carrier_ok(dev) || netif_dormant(dev) || |
100 | netif_testing(dev)) | |
8f4cccbb BH |
101 | rfc2863_policy(dev); |
102 | } | |
103 | ||
104 | ||
6fa9864b | 105 | static bool linkwatch_urgent_event(struct net_device *dev) |
294cc44b | 106 | { |
c37e0c99 ED |
107 | if (!netif_running(dev)) |
108 | return false; | |
109 | ||
a54acb3a | 110 | if (dev->ifindex != dev_get_iflink(dev)) |
c37e0c99 ED |
111 | return true; |
112 | ||
b76f4189 | 113 | if (netif_is_lag_port(dev) || netif_is_lag_master(dev)) |
194f4a6d FL |
114 | return true; |
115 | ||
c37e0c99 | 116 | return netif_carrier_ok(dev) && qdisc_tx_changing(dev); |
294cc44b HX |
117 | } |
118 | ||
119 | ||
120 | static void linkwatch_add_event(struct net_device *dev) | |
121 | { | |
122 | unsigned long flags; | |
123 | ||
124 | spin_lock_irqsave(&lweventlist_lock, flags); | |
e014debe ED |
125 | if (list_empty(&dev->link_watch_list)) { |
126 | list_add_tail(&dev->link_watch_list, &lweventlist); | |
d62607c3 | 127 | netdev_hold(dev, &dev->linkwatch_dev_tracker, GFP_ATOMIC); |
e014debe | 128 | } |
294cc44b HX |
129 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
130 | } | |
131 | ||
132 | ||
d9568ba9 | 133 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 134 | { |
d9568ba9 HX |
135 | unsigned long delay = linkwatch_nextevent - jiffies; |
136 | ||
137 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
138 | return; |
139 | ||
d9568ba9 HX |
140 | /* Minimise down-time: drop delay for up event. */ |
141 | if (urgent) { | |
142 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
143 | return; | |
294cc44b | 144 | delay = 0; |
db0ccffe | 145 | } |
294cc44b | 146 | |
d9568ba9 HX |
147 | /* If we wrap around we'll delay it by at most HZ. */ |
148 | if (delay > HZ) | |
149 | delay = 0; | |
150 | ||
151 | /* | |
e7c2f967 TH |
152 | * If urgent, schedule immediate execution; otherwise, don't |
153 | * override the existing timer. | |
d9568ba9 | 154 | */ |
e7c2f967 TH |
155 | if (test_bit(LW_URGENT, &linkwatch_flags)) |
156 | mod_delayed_work(system_wq, &linkwatch_work, 0); | |
157 | else | |
158 | schedule_delayed_work(&linkwatch_work, delay); | |
294cc44b HX |
159 | } |
160 | ||
161 | ||
e014debe ED |
162 | static void linkwatch_do_dev(struct net_device *dev) |
163 | { | |
164 | /* | |
165 | * Make sure the above read is complete since it can be | |
166 | * rewritten as soon as we clear the bit below. | |
167 | */ | |
4e857c58 | 168 | smp_mb__before_atomic(); |
e014debe ED |
169 | |
170 | /* We are about to handle this device, | |
171 | * so new events can be accepted | |
172 | */ | |
173 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
174 | ||
175 | rfc2863_policy(dev); | |
6922110d | 176 | if (dev->flags & IFF_UP) { |
e014debe ED |
177 | if (netif_carrier_ok(dev)) |
178 | dev_activate(dev); | |
179 | else | |
180 | dev_deactivate(dev); | |
181 | ||
182 | netdev_state_change(dev); | |
183 | } | |
4c6c11ea ED |
184 | /* Note: our callers are responsible for calling netdev_tracker_free(). |
185 | * This is the reason we use __dev_put() instead of dev_put(). | |
123e495e | 186 | */ |
4c6c11ea | 187 | __dev_put(dev); |
e014debe ED |
188 | } |
189 | ||
294cc44b | 190 | static void __linkwatch_run_queue(int urgent_only) |
1da177e4 | 191 | { |
27ba4059 YL |
192 | #define MAX_DO_DEV_PER_LOOP 100 |
193 | ||
194 | int do_dev = MAX_DO_DEV_PER_LOOP; | |
e014debe ED |
195 | struct net_device *dev; |
196 | LIST_HEAD(wrk); | |
1da177e4 | 197 | |
27ba4059 YL |
198 | /* Give urgent case more budget */ |
199 | if (urgent_only) | |
200 | do_dev += MAX_DO_DEV_PER_LOOP; | |
201 | ||
294cc44b HX |
202 | /* |
203 | * Limit the number of linkwatch events to one | |
204 | * per second so that a runaway driver does not | |
205 | * cause a storm of messages on the netlink | |
206 | * socket. This limit does not apply to up events | |
207 | * while the device qdisc is down. | |
208 | */ | |
209 | if (!urgent_only) | |
210 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
211 | /* Limit wrap-around effect on delay. */ |
212 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
213 | linkwatch_nextevent = jiffies; | |
214 | ||
215 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 216 | |
1da177e4 | 217 | spin_lock_irq(&lweventlist_lock); |
e014debe | 218 | list_splice_init(&lweventlist, &wrk); |
1da177e4 | 219 | |
27ba4059 | 220 | while (!list_empty(&wrk) && do_dev > 0) { |
1da177e4 | 221 | |
e014debe ED |
222 | dev = list_first_entry(&wrk, struct net_device, link_watch_list); |
223 | list_del_init(&dev->link_watch_list); | |
572a103d | 224 | |
6922110d WT |
225 | if (!netif_device_present(dev) || |
226 | (urgent_only && !linkwatch_urgent_event(dev))) { | |
e014debe | 227 | list_add_tail(&dev->link_watch_list, &lweventlist); |
294cc44b HX |
228 | continue; |
229 | } | |
123e495e ED |
230 | /* We must free netdev tracker under |
231 | * the spinlock protection. | |
232 | */ | |
233 | netdev_tracker_free(dev, &dev->linkwatch_dev_tracker); | |
e014debe ED |
234 | spin_unlock_irq(&lweventlist_lock); |
235 | linkwatch_do_dev(dev); | |
27ba4059 | 236 | do_dev--; |
e014debe | 237 | spin_lock_irq(&lweventlist_lock); |
1da177e4 | 238 | } |
294cc44b | 239 | |
27ba4059 YL |
240 | /* Add the remaining work back to lweventlist */ |
241 | list_splice_init(&wrk, &lweventlist); | |
242 | ||
e014debe | 243 | if (!list_empty(&lweventlist)) |
d9568ba9 | 244 | linkwatch_schedule_work(0); |
e014debe ED |
245 | spin_unlock_irq(&lweventlist_lock); |
246 | } | |
247 | ||
248 | void linkwatch_forget_dev(struct net_device *dev) | |
249 | { | |
250 | unsigned long flags; | |
251 | int clean = 0; | |
252 | ||
253 | spin_lock_irqsave(&lweventlist_lock, flags); | |
254 | if (!list_empty(&dev->link_watch_list)) { | |
255 | list_del_init(&dev->link_watch_list); | |
256 | clean = 1; | |
123e495e ED |
257 | /* We must release netdev tracker under |
258 | * the spinlock protection. | |
259 | */ | |
260 | netdev_tracker_free(dev, &dev->linkwatch_dev_tracker); | |
e014debe ED |
261 | } |
262 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
263 | if (clean) | |
264 | linkwatch_do_dev(dev); | |
4ec93edb | 265 | } |
1da177e4 LT |
266 | |
267 | ||
294cc44b HX |
268 | /* Must be called with the rtnl semaphore held */ |
269 | void linkwatch_run_queue(void) | |
1da177e4 | 270 | { |
294cc44b HX |
271 | __linkwatch_run_queue(0); |
272 | } | |
273 | ||
1da177e4 | 274 | |
294cc44b HX |
275 | static void linkwatch_event(struct work_struct *dummy) |
276 | { | |
6756ae4b | 277 | rtnl_lock(); |
294cc44b | 278 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 279 | rtnl_unlock(); |
1da177e4 LT |
280 | } |
281 | ||
282 | ||
283 | void linkwatch_fire_event(struct net_device *dev) | |
284 | { | |
6fa9864b | 285 | bool urgent = linkwatch_urgent_event(dev); |
1da177e4 | 286 | |
d9568ba9 | 287 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
294cc44b | 288 | linkwatch_add_event(dev); |
d9568ba9 HX |
289 | } else if (!urgent) |
290 | return; | |
1da177e4 | 291 | |
d9568ba9 | 292 | linkwatch_schedule_work(urgent); |
1da177e4 | 293 | } |
1da177e4 | 294 | EXPORT_SYMBOL(linkwatch_fire_event); |