Commit | Line | Data |
---|---|---|
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 LT |
20 | |
21 | ||
22 | enum lw_bits { | |
d9568ba9 | 23 | LW_URGENT = 0, |
1da177e4 LT |
24 | }; |
25 | ||
26 | static unsigned long linkwatch_flags; | |
27 | static unsigned long linkwatch_nextevent; | |
28 | ||
65f27f38 DH |
29 | static void linkwatch_event(struct work_struct *dummy); |
30 | static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event); | |
1da177e4 | 31 | |
e014debe | 32 | static LIST_HEAD(lweventlist); |
1da177e4 LT |
33 | static DEFINE_SPINLOCK(lweventlist_lock); |
34 | ||
b00055aa SR |
35 | static unsigned char default_operstate(const struct net_device *dev) |
36 | { | |
eec517cd AL |
37 | if (netif_testing(dev)) |
38 | return IF_OPER_TESTING; | |
39 | ||
b00055aa | 40 | if (!netif_carrier_ok(dev)) |
a54acb3a | 41 | return (dev->ifindex != dev_get_iflink(dev) ? |
b00055aa SR |
42 | IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN); |
43 | ||
44 | if (netif_dormant(dev)) | |
45 | return IF_OPER_DORMANT; | |
46 | ||
47 | return IF_OPER_UP; | |
48 | } | |
49 | ||
50 | ||
51 | static void rfc2863_policy(struct net_device *dev) | |
52 | { | |
53 | unsigned char operstate = default_operstate(dev); | |
54 | ||
55 | if (operstate == dev->operstate) | |
56 | return; | |
57 | ||
58 | write_lock_bh(&dev_base_lock); | |
59 | ||
60 | switch(dev->link_mode) { | |
eec517cd AL |
61 | case IF_LINK_MODE_TESTING: |
62 | if (operstate == IF_OPER_UP) | |
63 | operstate = IF_OPER_TESTING; | |
64 | break; | |
65 | ||
b00055aa SR |
66 | case IF_LINK_MODE_DORMANT: |
67 | if (operstate == IF_OPER_UP) | |
68 | operstate = IF_OPER_DORMANT; | |
69 | break; | |
b00055aa SR |
70 | case IF_LINK_MODE_DEFAULT: |
71 | default: | |
72 | break; | |
3ff50b79 | 73 | } |
b00055aa SR |
74 | |
75 | dev->operstate = operstate; | |
76 | ||
77 | write_unlock_bh(&dev_base_lock); | |
78 | } | |
79 | ||
80 | ||
8f4cccbb BH |
81 | void linkwatch_init_dev(struct net_device *dev) |
82 | { | |
83 | /* Handle pre-registration link state changes */ | |
eec517cd AL |
84 | if (!netif_carrier_ok(dev) || netif_dormant(dev) || |
85 | netif_testing(dev)) | |
8f4cccbb BH |
86 | rfc2863_policy(dev); |
87 | } | |
88 | ||
89 | ||
6fa9864b | 90 | static bool linkwatch_urgent_event(struct net_device *dev) |
294cc44b | 91 | { |
c37e0c99 ED |
92 | if (!netif_running(dev)) |
93 | return false; | |
94 | ||
a54acb3a | 95 | if (dev->ifindex != dev_get_iflink(dev)) |
c37e0c99 ED |
96 | return true; |
97 | ||
b76f4189 | 98 | if (netif_is_lag_port(dev) || netif_is_lag_master(dev)) |
194f4a6d FL |
99 | return true; |
100 | ||
c37e0c99 | 101 | return netif_carrier_ok(dev) && qdisc_tx_changing(dev); |
294cc44b HX |
102 | } |
103 | ||
104 | ||
105 | static void linkwatch_add_event(struct net_device *dev) | |
106 | { | |
107 | unsigned long flags; | |
108 | ||
109 | spin_lock_irqsave(&lweventlist_lock, flags); | |
e014debe ED |
110 | if (list_empty(&dev->link_watch_list)) { |
111 | list_add_tail(&dev->link_watch_list, &lweventlist); | |
112 | dev_hold(dev); | |
113 | } | |
294cc44b HX |
114 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
115 | } | |
116 | ||
117 | ||
d9568ba9 | 118 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 119 | { |
d9568ba9 HX |
120 | unsigned long delay = linkwatch_nextevent - jiffies; |
121 | ||
122 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
123 | return; |
124 | ||
d9568ba9 HX |
125 | /* Minimise down-time: drop delay for up event. */ |
126 | if (urgent) { | |
127 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
128 | return; | |
294cc44b | 129 | delay = 0; |
db0ccffe | 130 | } |
294cc44b | 131 | |
d9568ba9 HX |
132 | /* If we wrap around we'll delay it by at most HZ. */ |
133 | if (delay > HZ) | |
134 | delay = 0; | |
135 | ||
136 | /* | |
e7c2f967 TH |
137 | * If urgent, schedule immediate execution; otherwise, don't |
138 | * override the existing timer. | |
d9568ba9 | 139 | */ |
e7c2f967 TH |
140 | if (test_bit(LW_URGENT, &linkwatch_flags)) |
141 | mod_delayed_work(system_wq, &linkwatch_work, 0); | |
142 | else | |
143 | schedule_delayed_work(&linkwatch_work, delay); | |
294cc44b HX |
144 | } |
145 | ||
146 | ||
e014debe ED |
147 | static void linkwatch_do_dev(struct net_device *dev) |
148 | { | |
149 | /* | |
150 | * Make sure the above read is complete since it can be | |
151 | * rewritten as soon as we clear the bit below. | |
152 | */ | |
4e857c58 | 153 | smp_mb__before_atomic(); |
e014debe ED |
154 | |
155 | /* We are about to handle this device, | |
156 | * so new events can be accepted | |
157 | */ | |
158 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
159 | ||
160 | rfc2863_policy(dev); | |
124eee3f | 161 | if (dev->flags & IFF_UP && netif_device_present(dev)) { |
e014debe ED |
162 | if (netif_carrier_ok(dev)) |
163 | dev_activate(dev); | |
164 | else | |
165 | dev_deactivate(dev); | |
166 | ||
167 | netdev_state_change(dev); | |
168 | } | |
169 | dev_put(dev); | |
170 | } | |
171 | ||
294cc44b | 172 | static void __linkwatch_run_queue(int urgent_only) |
1da177e4 | 173 | { |
27ba4059 YL |
174 | #define MAX_DO_DEV_PER_LOOP 100 |
175 | ||
176 | int do_dev = MAX_DO_DEV_PER_LOOP; | |
e014debe ED |
177 | struct net_device *dev; |
178 | LIST_HEAD(wrk); | |
1da177e4 | 179 | |
27ba4059 YL |
180 | /* Give urgent case more budget */ |
181 | if (urgent_only) | |
182 | do_dev += MAX_DO_DEV_PER_LOOP; | |
183 | ||
294cc44b HX |
184 | /* |
185 | * Limit the number of linkwatch events to one | |
186 | * per second so that a runaway driver does not | |
187 | * cause a storm of messages on the netlink | |
188 | * socket. This limit does not apply to up events | |
189 | * while the device qdisc is down. | |
190 | */ | |
191 | if (!urgent_only) | |
192 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
193 | /* Limit wrap-around effect on delay. */ |
194 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
195 | linkwatch_nextevent = jiffies; | |
196 | ||
197 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 198 | |
1da177e4 | 199 | spin_lock_irq(&lweventlist_lock); |
e014debe | 200 | list_splice_init(&lweventlist, &wrk); |
1da177e4 | 201 | |
27ba4059 | 202 | while (!list_empty(&wrk) && do_dev > 0) { |
1da177e4 | 203 | |
e014debe ED |
204 | dev = list_first_entry(&wrk, struct net_device, link_watch_list); |
205 | list_del_init(&dev->link_watch_list); | |
572a103d | 206 | |
294cc44b | 207 | if (urgent_only && !linkwatch_urgent_event(dev)) { |
e014debe | 208 | list_add_tail(&dev->link_watch_list, &lweventlist); |
294cc44b HX |
209 | continue; |
210 | } | |
e014debe ED |
211 | spin_unlock_irq(&lweventlist_lock); |
212 | linkwatch_do_dev(dev); | |
27ba4059 | 213 | do_dev--; |
e014debe | 214 | spin_lock_irq(&lweventlist_lock); |
1da177e4 | 215 | } |
294cc44b | 216 | |
27ba4059 YL |
217 | /* Add the remaining work back to lweventlist */ |
218 | list_splice_init(&wrk, &lweventlist); | |
219 | ||
e014debe | 220 | if (!list_empty(&lweventlist)) |
d9568ba9 | 221 | linkwatch_schedule_work(0); |
e014debe ED |
222 | spin_unlock_irq(&lweventlist_lock); |
223 | } | |
224 | ||
225 | void linkwatch_forget_dev(struct net_device *dev) | |
226 | { | |
227 | unsigned long flags; | |
228 | int clean = 0; | |
229 | ||
230 | spin_lock_irqsave(&lweventlist_lock, flags); | |
231 | if (!list_empty(&dev->link_watch_list)) { | |
232 | list_del_init(&dev->link_watch_list); | |
233 | clean = 1; | |
234 | } | |
235 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
236 | if (clean) | |
237 | linkwatch_do_dev(dev); | |
4ec93edb | 238 | } |
1da177e4 LT |
239 | |
240 | ||
294cc44b HX |
241 | /* Must be called with the rtnl semaphore held */ |
242 | void linkwatch_run_queue(void) | |
1da177e4 | 243 | { |
294cc44b HX |
244 | __linkwatch_run_queue(0); |
245 | } | |
246 | ||
1da177e4 | 247 | |
294cc44b HX |
248 | static void linkwatch_event(struct work_struct *dummy) |
249 | { | |
6756ae4b | 250 | rtnl_lock(); |
294cc44b | 251 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 252 | rtnl_unlock(); |
1da177e4 LT |
253 | } |
254 | ||
255 | ||
256 | void linkwatch_fire_event(struct net_device *dev) | |
257 | { | |
6fa9864b | 258 | bool urgent = linkwatch_urgent_event(dev); |
1da177e4 | 259 | |
d9568ba9 | 260 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
294cc44b | 261 | linkwatch_add_event(dev); |
d9568ba9 HX |
262 | } else if (!urgent) |
263 | return; | |
1da177e4 | 264 | |
d9568ba9 | 265 | linkwatch_schedule_work(urgent); |
1da177e4 | 266 | } |
1da177e4 | 267 | EXPORT_SYMBOL(linkwatch_fire_event); |