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 | ||
6fa9864b | 79 | static bool linkwatch_urgent_event(struct net_device *dev) |
294cc44b | 80 | { |
c37e0c99 ED |
81 | if (!netif_running(dev)) |
82 | return false; | |
83 | ||
84 | if (dev->ifindex != dev->iflink) | |
85 | return true; | |
86 | ||
87 | return netif_carrier_ok(dev) && qdisc_tx_changing(dev); | |
294cc44b HX |
88 | } |
89 | ||
90 | ||
91 | static void linkwatch_add_event(struct net_device *dev) | |
92 | { | |
93 | unsigned long flags; | |
94 | ||
95 | spin_lock_irqsave(&lweventlist_lock, flags); | |
e014debe ED |
96 | if (list_empty(&dev->link_watch_list)) { |
97 | list_add_tail(&dev->link_watch_list, &lweventlist); | |
98 | dev_hold(dev); | |
99 | } | |
294cc44b HX |
100 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
101 | } | |
102 | ||
103 | ||
d9568ba9 | 104 | static void linkwatch_schedule_work(int urgent) |
294cc44b | 105 | { |
d9568ba9 HX |
106 | unsigned long delay = linkwatch_nextevent - jiffies; |
107 | ||
108 | if (test_bit(LW_URGENT, &linkwatch_flags)) | |
294cc44b HX |
109 | return; |
110 | ||
d9568ba9 HX |
111 | /* Minimise down-time: drop delay for up event. */ |
112 | if (urgent) { | |
113 | if (test_and_set_bit(LW_URGENT, &linkwatch_flags)) | |
114 | return; | |
294cc44b | 115 | delay = 0; |
db0ccffe | 116 | } |
294cc44b | 117 | |
d9568ba9 HX |
118 | /* If we wrap around we'll delay it by at most HZ. */ |
119 | if (delay > HZ) | |
120 | delay = 0; | |
121 | ||
122 | /* | |
123 | * This is true if we've scheduled it immeditately or if we don't | |
124 | * need an immediate execution and it's already pending. | |
125 | */ | |
126 | if (schedule_delayed_work(&linkwatch_work, delay) == !delay) | |
127 | return; | |
128 | ||
129 | /* Don't bother if there is nothing urgent. */ | |
130 | if (!test_bit(LW_URGENT, &linkwatch_flags)) | |
131 | return; | |
132 | ||
133 | /* It's already running which is good enough. */ | |
1821f7cd | 134 | if (!__cancel_delayed_work(&linkwatch_work)) |
d9568ba9 HX |
135 | return; |
136 | ||
25985edc | 137 | /* Otherwise we reschedule it again for immediate execution. */ |
d9568ba9 | 138 | schedule_delayed_work(&linkwatch_work, 0); |
294cc44b HX |
139 | } |
140 | ||
141 | ||
e014debe ED |
142 | static void linkwatch_do_dev(struct net_device *dev) |
143 | { | |
144 | /* | |
145 | * Make sure the above read is complete since it can be | |
146 | * rewritten as soon as we clear the bit below. | |
147 | */ | |
148 | smp_mb__before_clear_bit(); | |
149 | ||
150 | /* We are about to handle this device, | |
151 | * so new events can be accepted | |
152 | */ | |
153 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
154 | ||
155 | rfc2863_policy(dev); | |
156 | if (dev->flags & IFF_UP) { | |
157 | if (netif_carrier_ok(dev)) | |
158 | dev_activate(dev); | |
159 | else | |
160 | dev_deactivate(dev); | |
161 | ||
162 | netdev_state_change(dev); | |
163 | } | |
164 | dev_put(dev); | |
165 | } | |
166 | ||
294cc44b | 167 | static void __linkwatch_run_queue(int urgent_only) |
1da177e4 | 168 | { |
e014debe ED |
169 | struct net_device *dev; |
170 | LIST_HEAD(wrk); | |
1da177e4 | 171 | |
294cc44b HX |
172 | /* |
173 | * Limit the number of linkwatch events to one | |
174 | * per second so that a runaway driver does not | |
175 | * cause a storm of messages on the netlink | |
176 | * socket. This limit does not apply to up events | |
177 | * while the device qdisc is down. | |
178 | */ | |
179 | if (!urgent_only) | |
180 | linkwatch_nextevent = jiffies + HZ; | |
d9568ba9 HX |
181 | /* Limit wrap-around effect on delay. */ |
182 | else if (time_after(linkwatch_nextevent, jiffies + HZ)) | |
183 | linkwatch_nextevent = jiffies; | |
184 | ||
185 | clear_bit(LW_URGENT, &linkwatch_flags); | |
294cc44b | 186 | |
1da177e4 | 187 | spin_lock_irq(&lweventlist_lock); |
e014debe | 188 | list_splice_init(&lweventlist, &wrk); |
1da177e4 | 189 | |
e014debe | 190 | while (!list_empty(&wrk)) { |
1da177e4 | 191 | |
e014debe ED |
192 | dev = list_first_entry(&wrk, struct net_device, link_watch_list); |
193 | list_del_init(&dev->link_watch_list); | |
572a103d | 194 | |
294cc44b | 195 | if (urgent_only && !linkwatch_urgent_event(dev)) { |
e014debe | 196 | list_add_tail(&dev->link_watch_list, &lweventlist); |
294cc44b HX |
197 | continue; |
198 | } | |
e014debe ED |
199 | spin_unlock_irq(&lweventlist_lock); |
200 | linkwatch_do_dev(dev); | |
201 | spin_lock_irq(&lweventlist_lock); | |
1da177e4 | 202 | } |
294cc44b | 203 | |
e014debe | 204 | if (!list_empty(&lweventlist)) |
d9568ba9 | 205 | linkwatch_schedule_work(0); |
e014debe ED |
206 | spin_unlock_irq(&lweventlist_lock); |
207 | } | |
208 | ||
209 | void linkwatch_forget_dev(struct net_device *dev) | |
210 | { | |
211 | unsigned long flags; | |
212 | int clean = 0; | |
213 | ||
214 | spin_lock_irqsave(&lweventlist_lock, flags); | |
215 | if (!list_empty(&dev->link_watch_list)) { | |
216 | list_del_init(&dev->link_watch_list); | |
217 | clean = 1; | |
218 | } | |
219 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
220 | if (clean) | |
221 | linkwatch_do_dev(dev); | |
4ec93edb | 222 | } |
1da177e4 LT |
223 | |
224 | ||
294cc44b HX |
225 | /* Must be called with the rtnl semaphore held */ |
226 | void linkwatch_run_queue(void) | |
1da177e4 | 227 | { |
294cc44b HX |
228 | __linkwatch_run_queue(0); |
229 | } | |
230 | ||
1da177e4 | 231 | |
294cc44b HX |
232 | static void linkwatch_event(struct work_struct *dummy) |
233 | { | |
6756ae4b | 234 | rtnl_lock(); |
294cc44b | 235 | __linkwatch_run_queue(time_after(linkwatch_nextevent, jiffies)); |
6756ae4b | 236 | rtnl_unlock(); |
1da177e4 LT |
237 | } |
238 | ||
239 | ||
240 | void linkwatch_fire_event(struct net_device *dev) | |
241 | { | |
6fa9864b | 242 | bool urgent = linkwatch_urgent_event(dev); |
1da177e4 | 243 | |
d9568ba9 | 244 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
294cc44b | 245 | linkwatch_add_event(dev); |
d9568ba9 HX |
246 | } else if (!urgent) |
247 | return; | |
1da177e4 | 248 | |
d9568ba9 | 249 | linkwatch_schedule_work(urgent); |
1da177e4 | 250 | } |
1da177e4 | 251 | EXPORT_SYMBOL(linkwatch_fire_event); |