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/slab.h> |
23 | #include <linux/workqueue.h> | |
24 | #include <linux/bitops.h> | |
25 | #include <asm/types.h> | |
26 | ||
27 | ||
28 | enum lw_bits { | |
d9568ba9 | 29 | LW_URGENT = 0, |
1da177e4 LT |
30 | }; |
31 | ||
32 | static unsigned long linkwatch_flags; | |
33 | static unsigned long linkwatch_nextevent; | |
34 | ||
65f27f38 DH |
35 | static void linkwatch_event(struct work_struct *dummy); |
36 | static DECLARE_DELAYED_WORK(linkwatch_work, linkwatch_event); | |
1da177e4 | 37 | |
e014debe | 38 | static LIST_HEAD(lweventlist); |
1da177e4 LT |
39 | static DEFINE_SPINLOCK(lweventlist_lock); |
40 | ||
b00055aa SR |
41 | static unsigned char default_operstate(const struct net_device *dev) |
42 | { | |
43 | if (!netif_carrier_ok(dev)) | |
44 | return (dev->ifindex != dev->iflink ? | |
45 | IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN); | |
46 | ||
47 | if (netif_dormant(dev)) | |
48 | return IF_OPER_DORMANT; | |
49 | ||
50 | return IF_OPER_UP; | |
51 | } | |
52 | ||
53 | ||
54 | static void rfc2863_policy(struct net_device *dev) | |
55 | { | |
56 | unsigned char operstate = default_operstate(dev); | |
57 | ||
58 | if (operstate == dev->operstate) | |
59 | return; | |
60 | ||
61 | write_lock_bh(&dev_base_lock); | |
62 | ||
63 | switch(dev->link_mode) { | |
64 | case IF_LINK_MODE_DORMANT: | |
65 | if (operstate == IF_OPER_UP) | |
66 | operstate = IF_OPER_DORMANT; | |
67 | break; | |
68 | ||
69 | case IF_LINK_MODE_DEFAULT: | |
70 | default: | |
71 | break; | |
3ff50b79 | 72 | } |
b00055aa SR |
73 | |
74 | dev->operstate = operstate; | |
75 | ||
76 | write_unlock_bh(&dev_base_lock); | |
77 | } | |
78 | ||
79 | ||
6fa9864b | 80 | static bool linkwatch_urgent_event(struct net_device *dev) |
294cc44b HX |
81 | { |
82 | return netif_running(dev) && netif_carrier_ok(dev) && | |
6fa9864b | 83 | qdisc_tx_changing(dev); |
294cc44b HX |
84 | } |
85 | ||
86 | ||
87 | static void linkwatch_add_event(struct net_device *dev) | |
88 | { | |
89 | unsigned long flags; | |
90 | ||
91 | spin_lock_irqsave(&lweventlist_lock, flags); | |
e014debe ED |
92 | if (list_empty(&dev->link_watch_list)) { |
93 | list_add_tail(&dev->link_watch_list, &lweventlist); | |
94 | dev_hold(dev); | |
95 | } | |
294cc44b HX |
96 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
97 | } | |
98 | ||
99 | ||
d9568ba9 | 100 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 101 | { |
d9568ba9 HX |
102 | unsigned long delay = linkwatch_nextevent - jiffies; |
103 | ||
104 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
105 | return; |
106 | ||
d9568ba9 HX |
107 | /* Minimise down-time: drop delay for up event. */ |
108 | if (urgent) { | |
109 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
110 | return; | |
294cc44b | 111 | delay = 0; |
db0ccffe | 112 | } |
294cc44b | 113 | |
d9568ba9 HX |
114 | /* If we wrap around we'll delay it by at most HZ. */ |
115 | if (delay > HZ) | |
116 | delay = 0; | |
117 | ||
118 | /* | |
119 | * This is true if we've scheduled it immeditately or if we don't | |
120 | * need an immediate execution and it's already pending. | |
121 | */ | |
122 | if (schedule_delayed_work(&linkwatch_work, delay) == !delay) | |
123 | return; | |
124 | ||
125 | /* Don't bother if there is nothing urgent. */ | |
126 | if (!test_bit(LW_URGENT, &linkwatch_flags)) | |
127 | return; | |
128 | ||
129 | /* It's already running which is good enough. */ | |
130 | if (!cancel_delayed_work(&linkwatch_work)) | |
131 | return; | |
132 | ||
133 | /* Otherwise we reschedule it again for immediate exection. */ | |
134 | schedule_delayed_work(&linkwatch_work, 0); | |
294cc44b HX |
135 | } |
136 | ||
137 | ||
e014debe ED |
138 | static void linkwatch_do_dev(struct net_device *dev) |
139 | { | |
140 | /* | |
141 | * Make sure the above read is complete since it can be | |
142 | * rewritten as soon as we clear the bit below. | |
143 | */ | |
144 | smp_mb__before_clear_bit(); | |
145 | ||
146 | /* We are about to handle this device, | |
147 | * so new events can be accepted | |
148 | */ | |
149 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
150 | ||
151 | rfc2863_policy(dev); | |
152 | if (dev->flags & IFF_UP) { | |
153 | if (netif_carrier_ok(dev)) | |
154 | dev_activate(dev); | |
155 | else | |
156 | dev_deactivate(dev); | |
157 | ||
158 | netdev_state_change(dev); | |
159 | } | |
160 | dev_put(dev); | |
161 | } | |
162 | ||
294cc44b | 163 | static void __linkwatch_run_queue(int urgent_only) |
1da177e4 | 164 | { |
e014debe ED |
165 | struct net_device *dev; |
166 | LIST_HEAD(wrk); | |
1da177e4 | 167 | |
294cc44b HX |
168 | /* |
169 | * Limit the number of linkwatch events to one | |
170 | * per second so that a runaway driver does not | |
171 | * cause a storm of messages on the netlink | |
172 | * socket. This limit does not apply to up events | |
173 | * while the device qdisc is down. | |
174 | */ | |
175 | if (!urgent_only) | |
176 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
177 | /* Limit wrap-around effect on delay. */ |
178 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
179 | linkwatch_nextevent = jiffies; | |
180 | ||
181 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 182 | |
1da177e4 | 183 | spin_lock_irq(&lweventlist_lock); |
e014debe | 184 | list_splice_init(&lweventlist, &wrk); |
1da177e4 | 185 | |
e014debe | 186 | while (!list_empty(&wrk)) { |
1da177e4 | 187 | |
e014debe ED |
188 | dev = list_first_entry(&wrk, struct net_device, link_watch_list); |
189 | list_del_init(&dev->link_watch_list); | |
572a103d | 190 | |
294cc44b | 191 | if (urgent_only && !linkwatch_urgent_event(dev)) { |
e014debe | 192 | list_add_tail(&dev->link_watch_list, &lweventlist); |
294cc44b HX |
193 | continue; |
194 | } | |
e014debe ED |
195 | spin_unlock_irq(&lweventlist_lock); |
196 | linkwatch_do_dev(dev); | |
197 | spin_lock_irq(&lweventlist_lock); | |
1da177e4 | 198 | } |
294cc44b | 199 | |
e014debe | 200 | if (!list_empty(&lweventlist)) |
d9568ba9 | 201 | linkwatch_schedule_work(0); |
e014debe ED |
202 | spin_unlock_irq(&lweventlist_lock); |
203 | } | |
204 | ||
205 | void linkwatch_forget_dev(struct net_device *dev) | |
206 | { | |
207 | unsigned long flags; | |
208 | int clean = 0; | |
209 | ||
210 | spin_lock_irqsave(&lweventlist_lock, flags); | |
211 | if (!list_empty(&dev->link_watch_list)) { | |
212 | list_del_init(&dev->link_watch_list); | |
213 | clean = 1; | |
214 | } | |
215 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
216 | if (clean) | |
217 | linkwatch_do_dev(dev); | |
4ec93edb | 218 | } |
1da177e4 LT |
219 | |
220 | ||
294cc44b HX |
221 | /* Must be called with the rtnl semaphore held */ |
222 | void linkwatch_run_queue(void) | |
1da177e4 | 223 | { |
294cc44b HX |
224 | __linkwatch_run_queue(0); |
225 | } | |
226 | ||
1da177e4 | 227 | |
294cc44b HX |
228 | static void linkwatch_event(struct work_struct *dummy) |
229 | { | |
6756ae4b | 230 | rtnl_lock(); |
294cc44b | 231 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 232 | rtnl_unlock(); |
1da177e4 LT |
233 | } |
234 | ||
235 | ||
236 | void linkwatch_fire_event(struct net_device *dev) | |
237 | { | |
6fa9864b | 238 | bool urgent = linkwatch_urgent_event(dev); |
1da177e4 | 239 | |
d9568ba9 | 240 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
294cc44b | 241 | linkwatch_add_event(dev); |
d9568ba9 HX |
242 | } else if (!urgent) |
243 | return; | |
1da177e4 | 244 | |
d9568ba9 | 245 | linkwatch_schedule_work(urgent); |
1da177e4 LT |
246 | } |
247 | ||
248 | EXPORT_SYMBOL(linkwatch_fire_event); |