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 | |
572a103d | 38 | static struct net_device *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 | ||
294cc44b HX |
80 | static int linkwatch_urgent_event(struct net_device *dev) |
81 | { | |
82 | return netif_running(dev) && netif_carrier_ok(dev) && | |
83 | dev->qdisc != dev->qdisc_sleeping; | |
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); | |
92 | dev->link_watch_next = lweventlist; | |
93 | lweventlist = dev; | |
94 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
95 | } | |
96 | ||
97 | ||
d9568ba9 | 98 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 99 | { |
d9568ba9 HX |
100 | unsigned long delay = linkwatch_nextevent - jiffies; |
101 | ||
102 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
103 | return; |
104 | ||
d9568ba9 HX |
105 | /* Minimise down-time: drop delay for up event. */ |
106 | if (urgent) { | |
107 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
108 | return; | |
294cc44b | 109 | delay = 0; |
db0ccffe | 110 | } |
294cc44b | 111 | |
d9568ba9 HX |
112 | /* If we wrap around we'll delay it by at most HZ. */ |
113 | if (delay > HZ) | |
114 | delay = 0; | |
115 | ||
116 | /* | |
117 | * This is true if we've scheduled it immeditately or if we don't | |
118 | * need an immediate execution and it's already pending. | |
119 | */ | |
120 | if (schedule_delayed_work(&linkwatch_work, delay) == !delay) | |
121 | return; | |
122 | ||
123 | /* Don't bother if there is nothing urgent. */ | |
124 | if (!test_bit(LW_URGENT, &linkwatch_flags)) | |
125 | return; | |
126 | ||
127 | /* It's already running which is good enough. */ | |
128 | if (!cancel_delayed_work(&linkwatch_work)) | |
129 | return; | |
130 | ||
131 | /* Otherwise we reschedule it again for immediate exection. */ | |
132 | schedule_delayed_work(&linkwatch_work, 0); | |
294cc44b HX |
133 | } |
134 | ||
135 | ||
136 | static void __linkwatch_run_queue(int urgent_only) | |
1da177e4 | 137 | { |
572a103d | 138 | struct net_device *next; |
1da177e4 | 139 | |
294cc44b HX |
140 | /* |
141 | * Limit the number of linkwatch events to one | |
142 | * per second so that a runaway driver does not | |
143 | * cause a storm of messages on the netlink | |
144 | * socket. This limit does not apply to up events | |
145 | * while the device qdisc is down. | |
146 | */ | |
147 | if (!urgent_only) | |
148 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
149 | /* Limit wrap-around effect on delay. */ |
150 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
151 | linkwatch_nextevent = jiffies; | |
152 | ||
153 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 154 | |
1da177e4 | 155 | spin_lock_irq(&lweventlist_lock); |
572a103d HX |
156 | next = lweventlist; |
157 | lweventlist = NULL; | |
1da177e4 LT |
158 | spin_unlock_irq(&lweventlist_lock); |
159 | ||
572a103d HX |
160 | while (next) { |
161 | struct net_device *dev = next; | |
1da177e4 | 162 | |
572a103d HX |
163 | next = dev->link_watch_next; |
164 | ||
294cc44b HX |
165 | if (urgent_only && !linkwatch_urgent_event(dev)) { |
166 | linkwatch_add_event(dev); | |
167 | continue; | |
168 | } | |
169 | ||
572a103d HX |
170 | /* |
171 | * Make sure the above read is complete since it can be | |
172 | * rewritten as soon as we clear the bit below. | |
173 | */ | |
174 | smp_mb__before_clear_bit(); | |
1da177e4 LT |
175 | |
176 | /* We are about to handle this device, | |
177 | * so new events can be accepted | |
178 | */ | |
179 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
180 | ||
b00055aa | 181 | rfc2863_policy(dev); |
1da177e4 | 182 | if (dev->flags & IFF_UP) { |
cacaddf5 TC |
183 | if (netif_carrier_ok(dev)) { |
184 | WARN_ON(dev->qdisc_sleeping == &noop_qdisc); | |
185 | dev_activate(dev); | |
186 | } else | |
187 | dev_deactivate(dev); | |
188 | ||
1da177e4 LT |
189 | netdev_state_change(dev); |
190 | } | |
191 | ||
192 | dev_put(dev); | |
193 | } | |
294cc44b HX |
194 | |
195 | if (lweventlist) | |
d9568ba9 | 196 | linkwatch_schedule_work(0); |
4ec93edb | 197 | } |
1da177e4 LT |
198 | |
199 | ||
294cc44b HX |
200 | /* Must be called with the rtnl semaphore held */ |
201 | void linkwatch_run_queue(void) | |
1da177e4 | 202 | { |
294cc44b HX |
203 | __linkwatch_run_queue(0); |
204 | } | |
205 | ||
1da177e4 | 206 | |
294cc44b HX |
207 | static void linkwatch_event(struct work_struct *dummy) |
208 | { | |
6756ae4b | 209 | rtnl_lock(); |
294cc44b | 210 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 211 | rtnl_unlock(); |
1da177e4 LT |
212 | } |
213 | ||
214 | ||
215 | void linkwatch_fire_event(struct net_device *dev) | |
216 | { | |
d9568ba9 | 217 | int urgent = linkwatch_urgent_event(dev); |
1da177e4 | 218 | |
d9568ba9 | 219 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
1da177e4 | 220 | dev_hold(dev); |
1da177e4 | 221 | |
294cc44b | 222 | linkwatch_add_event(dev); |
d9568ba9 HX |
223 | } else if (!urgent) |
224 | return; | |
1da177e4 | 225 | |
d9568ba9 | 226 | linkwatch_schedule_work(urgent); |
1da177e4 LT |
227 | } |
228 | ||
229 | EXPORT_SYMBOL(linkwatch_fire_event); |