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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 | ||
14 | #include <linux/config.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/netdevice.h> | |
17 | #include <linux/if.h> | |
18 | #include <net/sock.h> | |
cacaddf5 | 19 | #include <net/pkt_sched.h> |
1da177e4 LT |
20 | #include <linux/rtnetlink.h> |
21 | #include <linux/jiffies.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/list.h> | |
24 | #include <linux/slab.h> | |
25 | #include <linux/workqueue.h> | |
26 | #include <linux/bitops.h> | |
27 | #include <asm/types.h> | |
28 | ||
29 | ||
30 | enum lw_bits { | |
31 | LW_RUNNING = 0, | |
32 | LW_SE_USED | |
33 | }; | |
34 | ||
35 | static unsigned long linkwatch_flags; | |
36 | static unsigned long linkwatch_nextevent; | |
37 | ||
38 | static void linkwatch_event(void *dummy); | |
39 | static DECLARE_WORK(linkwatch_work, linkwatch_event, NULL); | |
40 | ||
41 | static LIST_HEAD(lweventlist); | |
42 | static DEFINE_SPINLOCK(lweventlist_lock); | |
43 | ||
44 | struct lw_event { | |
45 | struct list_head list; | |
46 | struct net_device *dev; | |
47 | }; | |
48 | ||
49 | /* Avoid kmalloc() for most systems */ | |
50 | static struct lw_event singleevent; | |
51 | ||
b00055aa SR |
52 | static unsigned char default_operstate(const struct net_device *dev) |
53 | { | |
54 | if (!netif_carrier_ok(dev)) | |
55 | return (dev->ifindex != dev->iflink ? | |
56 | IF_OPER_LOWERLAYERDOWN : IF_OPER_DOWN); | |
57 | ||
58 | if (netif_dormant(dev)) | |
59 | return IF_OPER_DORMANT; | |
60 | ||
61 | return IF_OPER_UP; | |
62 | } | |
63 | ||
64 | ||
65 | static void rfc2863_policy(struct net_device *dev) | |
66 | { | |
67 | unsigned char operstate = default_operstate(dev); | |
68 | ||
69 | if (operstate == dev->operstate) | |
70 | return; | |
71 | ||
72 | write_lock_bh(&dev_base_lock); | |
73 | ||
74 | switch(dev->link_mode) { | |
75 | case IF_LINK_MODE_DORMANT: | |
76 | if (operstate == IF_OPER_UP) | |
77 | operstate = IF_OPER_DORMANT; | |
78 | break; | |
79 | ||
80 | case IF_LINK_MODE_DEFAULT: | |
81 | default: | |
82 | break; | |
83 | }; | |
84 | ||
85 | dev->operstate = operstate; | |
86 | ||
87 | write_unlock_bh(&dev_base_lock); | |
88 | } | |
89 | ||
90 | ||
1da177e4 LT |
91 | /* Must be called with the rtnl semaphore held */ |
92 | void linkwatch_run_queue(void) | |
93 | { | |
626ab0e6 | 94 | struct list_head head, *n, *next; |
1da177e4 LT |
95 | |
96 | spin_lock_irq(&lweventlist_lock); | |
626ab0e6 | 97 | list_replace_init(&lweventlist, &head); |
1da177e4 LT |
98 | spin_unlock_irq(&lweventlist_lock); |
99 | ||
100 | list_for_each_safe(n, next, &head) { | |
101 | struct lw_event *event = list_entry(n, struct lw_event, list); | |
102 | struct net_device *dev = event->dev; | |
103 | ||
104 | if (event == &singleevent) { | |
105 | clear_bit(LW_SE_USED, &linkwatch_flags); | |
106 | } else { | |
107 | kfree(event); | |
108 | } | |
109 | ||
110 | /* We are about to handle this device, | |
111 | * so new events can be accepted | |
112 | */ | |
113 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
114 | ||
b00055aa | 115 | rfc2863_policy(dev); |
1da177e4 | 116 | if (dev->flags & IFF_UP) { |
cacaddf5 TC |
117 | if (netif_carrier_ok(dev)) { |
118 | WARN_ON(dev->qdisc_sleeping == &noop_qdisc); | |
119 | dev_activate(dev); | |
120 | } else | |
121 | dev_deactivate(dev); | |
122 | ||
1da177e4 LT |
123 | netdev_state_change(dev); |
124 | } | |
125 | ||
126 | dev_put(dev); | |
127 | } | |
128 | } | |
129 | ||
130 | ||
131 | static void linkwatch_event(void *dummy) | |
132 | { | |
133 | /* Limit the number of linkwatch events to one | |
134 | * per second so that a runaway driver does not | |
135 | * cause a storm of messages on the netlink | |
136 | * socket | |
137 | */ | |
138 | linkwatch_nextevent = jiffies + HZ; | |
139 | clear_bit(LW_RUNNING, &linkwatch_flags); | |
140 | ||
6756ae4b | 141 | rtnl_lock(); |
1da177e4 | 142 | linkwatch_run_queue(); |
6756ae4b | 143 | rtnl_unlock(); |
1da177e4 LT |
144 | } |
145 | ||
146 | ||
147 | void linkwatch_fire_event(struct net_device *dev) | |
148 | { | |
149 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { | |
150 | unsigned long flags; | |
151 | struct lw_event *event; | |
152 | ||
153 | if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) { | |
154 | event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC); | |
155 | ||
156 | if (unlikely(event == NULL)) { | |
157 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); | |
158 | return; | |
159 | } | |
160 | } else { | |
161 | event = &singleevent; | |
162 | } | |
163 | ||
164 | dev_hold(dev); | |
165 | event->dev = dev; | |
166 | ||
167 | spin_lock_irqsave(&lweventlist_lock, flags); | |
168 | list_add_tail(&event->list, &lweventlist); | |
169 | spin_unlock_irqrestore(&lweventlist_lock, flags); | |
170 | ||
171 | if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) { | |
8c105683 | 172 | unsigned long delay = linkwatch_nextevent - jiffies; |
1da177e4 | 173 | |
8c105683 HX |
174 | /* If we wrap around we'll delay it by at most HZ. */ |
175 | if (!delay || delay > HZ) | |
1da177e4 | 176 | schedule_work(&linkwatch_work); |
8c105683 HX |
177 | else |
178 | schedule_delayed_work(&linkwatch_work, delay); | |
1da177e4 LT |
179 | } |
180 | } | |
181 | } | |
182 | ||
183 | EXPORT_SYMBOL(linkwatch_fire_event); |