Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Linux network device link state notification | |
3 | * | |
4 | * Author: | |
5 | * Stefan Rompf <sux@loplof.de> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License | |
9 | * as published by the Free Software Foundation; either version | |
10 | * 2 of the License, or (at your option) any later version. | |
11 | * | |
12 | */ | |
13 | ||
1da177e4 LT |
14 | #include <linux/module.h> |
15 | #include <linux/netdevice.h> | |
16 | #include <linux/if.h> | |
17 | #include <net/sock.h> | |
cacaddf5 | 18 | #include <net/pkt_sched.h> |
1da177e4 LT |
19 | #include <linux/rtnetlink.h> |
20 | #include <linux/jiffies.h> | |
21 | #include <linux/spinlock.h> | |
1da177e4 LT |
22 | #include <linux/workqueue.h> |
23 | #include <linux/bitops.h> | |
24 | #include <asm/types.h> | |
25 | ||
26 | ||
27 | enum lw_bits { | |
d9568ba9 | 28 | LW_URGENT = 0, |
1da177e4 LT |
29 | }; |
30 | ||
31 | static unsigned long linkwatch_flags; | |
32 | static unsigned long linkwatch_nextevent; | |
33 | ||
65f27f38 DH |
34 | static void linkwatch_event(struct work_struct *dummy); |
35 | static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event); | |
1da177e4 | 36 | |
e014debe | 37 | static LIST_HEAD(lweventlist); |
1da177e4 LT |
38 | static DEFINE_SPINLOCK(lweventlist_lock); |
39 | ||
b00055aa SR |
40 | static unsigned char default_operstate(const struct net_device *dev) |
41 | { | |
42 | if (!netif_carrier_ok(dev)) | |
43 | return (dev->ifindex != dev->iflink ? | |
44 | IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN); | |
45 | ||
46 | if (netif_dormant(dev)) | |
47 | return IF_OPER_DORMANT; | |
48 | ||
49 | return IF_OPER_UP; | |
50 | } | |
51 | ||
52 | ||
53 | static void rfc2863_policy(struct net_device *dev) | |
54 | { | |
55 | unsigned char operstate = default_operstate(dev); | |
56 | ||
57 | if (operstate == dev->operstate) | |
58 | return; | |
59 | ||
60 | write_lock_bh(&dev_base_lock); | |
61 | ||
62 | switch(dev->link_mode) { | |
63 | case IF_LINK_MODE_DORMANT: | |
64 | if (operstate == IF_OPER_UP) | |
65 | operstate = IF_OPER_DORMANT; | |
66 | break; | |
67 | ||
68 | case IF_LINK_MODE_DEFAULT: | |
69 | default: | |
70 | break; | |
3ff50b79 | 71 | } |
b00055aa SR |
72 | |
73 | dev->operstate = operstate; | |
74 | ||
75 | write_unlock_bh(&dev_base_lock); | |
76 | } | |
77 | ||
78 | ||
8f4cccbb BH |
79 | void linkwatch_init_dev(struct net_device *dev) |
80 | { | |
81 | /* Handle pre-registration link state changes */ | |
82 | if (!netif_carrier_ok(dev) || netif_dormant(dev)) | |
83 | rfc2863_policy(dev); | |
84 | } | |
85 | ||
86 | ||
6fa9864b | 87 | static bool linkwatch_urgent_event(struct net_device *dev) |
294cc44b | 88 | { |
c37e0c99 ED |
89 | if (!netif_running(dev)) |
90 | return false; | |
91 | ||
92 | if (dev->ifindex != dev->iflink) | |
93 | return true; | |
94 | ||
95 | return netif_carrier_ok(dev) && qdisc_tx_changing(dev); | |
294cc44b HX |
96 | } |
97 | ||
98 | ||
99 | static void linkwatch_add_event(struct net_device *dev) | |
100 | { | |
101 | unsigned long flags; | |
102 | ||
103 | spin_lock_irqsave(&lweventlist_lock, flags); | |
e014debe ED |
104 | if (list_empty(&dev->link_watch_list)) { |
105 | list_add_tail(&dev->link_watch_list, &lweventlist); | |
106 | dev_hold(dev); | |
107 | } | |
294cc44b HX |
108 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
109 | } | |
110 | ||
111 | ||
d9568ba9 | 112 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 113 | { |
d9568ba9 HX |
114 | unsigned long delay = linkwatch_nextevent - jiffies; |
115 | ||
116 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
117 | return; |
118 | ||
d9568ba9 HX |
119 | /* Minimise down-time: drop delay for up event. */ |
120 | if (urgent) { | |
121 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
122 | return; | |
294cc44b | 123 | delay = 0; |
db0ccffe | 124 | } |
294cc44b | 125 | |
d9568ba9 HX |
126 | /* If we wrap around we'll delay it by at most HZ. */ |
127 | if (delay > HZ) | |
128 | delay = 0; | |
129 | ||
130 | /* | |
e7c2f967 TH |
131 | * If urgent, schedule immediate execution; otherwise, don't |
132 | * override the existing timer. | |
d9568ba9 | 133 | */ |
e7c2f967 TH |
134 | if (test_bit(LW_URGENT, &linkwatch_flags)) |
135 | mod_delayed_work(system_wq, &linkwatch_work, 0); | |
136 | else | |
137 | schedule_delayed_work(&linkwatch_work, delay); | |
294cc44b HX |
138 | } |
139 | ||
140 | ||
e014debe ED |
141 | static void linkwatch_do_dev(struct net_device *dev) |
142 | { | |
143 | /* | |
144 | * Make sure the above read is complete since it can be | |
145 | * rewritten as soon as we clear the bit below. | |
146 | */ | |
147 | smp_mb__before_clear_bit(); | |
148 | ||
149 | /* We are about to handle this device, | |
150 | * so new events can be accepted | |
151 | */ | |
152 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
153 | ||
154 | rfc2863_policy(dev); | |
155 | if (dev->flags & IFF_UP) { | |
156 | if (netif_carrier_ok(dev)) | |
157 | dev_activate(dev); | |
158 | else | |
159 | dev_deactivate(dev); | |
160 | ||
161 | netdev_state_change(dev); | |
162 | } | |
163 | dev_put(dev); | |
164 | } | |
165 | ||
294cc44b | 166 | static void __linkwatch_run_queue(int urgent_only) |
1da177e4 | 167 | { |
e014debe ED |
168 | struct net_device *dev; |
169 | LIST_HEAD(wrk); | |
1da177e4 | 170 | |
294cc44b HX |
171 | /* |
172 | * Limit the number of linkwatch events to one | |
173 | * per second so that a runaway driver does not | |
174 | * cause a storm of messages on the netlink | |
175 | * socket. This limit does not apply to up events | |
176 | * while the device qdisc is down. | |
177 | */ | |
178 | if (!urgent_only) | |
179 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
180 | /* Limit wrap-around effect on delay. */ |
181 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
182 | linkwatch_nextevent = jiffies; | |
183 | ||
184 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 185 | |
1da177e4 | 186 | spin_lock_irq(&lweventlist_lock); |
e014debe | 187 | list_splice_init(&lweventlist, &wrk); |
1da177e4 | 188 | |
e014debe | 189 | while (!list_empty(&wrk)) { |
1da177e4 | 190 | |
e014debe ED |
191 | dev = list_first_entry(&wrk, struct net_device, link_watch_list); |
192 | list_del_init(&dev->link_watch_list); | |
572a103d | 193 | |
294cc44b | 194 | if (urgent_only && !linkwatch_urgent_event(dev)) { |
e014debe | 195 | list_add_tail(&dev->link_watch_list, &lweventlist); |
294cc44b HX |
196 | continue; |
197 | } | |
e014debe ED |
198 | spin_unlock_irq(&lweventlist_lock); |
199 | linkwatch_do_dev(dev); | |
200 | spin_lock_irq(&lweventlist_lock); | |
1da177e4 | 201 | } |
294cc44b | 202 | |
e014debe | 203 | if (!list_empty(&lweventlist)) |
d9568ba9 | 204 | linkwatch_schedule_work(0); |
e014debe ED |
205 | spin_unlock_irq(&lweventlist_lock); |
206 | } | |
207 | ||
208 | void linkwatch_forget_dev(struct net_device *dev) | |
209 | { | |
210 | unsigned long flags; | |
211 | int clean = 0; | |
212 | ||
213 | spin_lock_irqsave(&lweventlist_lock, flags); | |
214 | if (!list_empty(&dev->link_watch_list)) { | |
215 | list_del_init(&dev->link_watch_list); | |
216 | clean = 1; | |
217 | } | |
218 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
219 | if (clean) | |
220 | linkwatch_do_dev(dev); | |
4ec93edb | 221 | } |
1da177e4 LT |
222 | |
223 | ||
294cc44b HX |
224 | /* Must be called with the rtnl semaphore held */ |
225 | void linkwatch_run_queue(void) | |
1da177e4 | 226 | { |
294cc44b HX |
227 | __linkwatch_run_queue(0); |
228 | } | |
229 | ||
1da177e4 | 230 | |
294cc44b HX |
231 | static void linkwatch_event(struct work_struct *dummy) |
232 | { | |
6756ae4b | 233 | rtnl_lock(); |
294cc44b | 234 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 235 | rtnl_unlock(); |
1da177e4 LT |
236 | } |
237 | ||
238 | ||
239 | void linkwatch_fire_event(struct net_device *dev) | |
240 | { | |
6fa9864b | 241 | bool urgent = linkwatch_urgent_event(dev); |
1da177e4 | 242 | |
d9568ba9 | 243 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
294cc44b | 244 | linkwatch_add_event(dev); |
d9568ba9 HX |
245 | } else if (!urgent) |
246 | return; | |
1da177e4 | 247 | |
d9568ba9 | 248 | linkwatch_schedule_work(urgent); |
1da177e4 | 249 | } |
1da177e4 | 250 | EXPORT_SYMBOL(linkwatch_fire_event); |