Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Tommy S. Christensen | cacaddf | 2005-05-03 16:18:52 -0700 | [diff] [blame] | 19 | #include <net/pkt_sched.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Stefan Rompf | b00055a | 2006-03-20 17:09:11 -0800 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 91 | /* Must be called with the rtnl semaphore held */ |
| 92 | void linkwatch_run_queue(void) |
| 93 | { |
| 94 | LIST_HEAD(head); |
| 95 | struct list_head *n, *next; |
| 96 | |
| 97 | spin_lock_irq(&lweventlist_lock); |
| 98 | list_splice_init(&lweventlist, &head); |
| 99 | spin_unlock_irq(&lweventlist_lock); |
| 100 | |
| 101 | list_for_each_safe(n, next, &head) { |
| 102 | struct lw_event *event = list_entry(n, struct lw_event, list); |
| 103 | struct net_device *dev = event->dev; |
| 104 | |
| 105 | if (event == &singleevent) { |
| 106 | clear_bit(LW_SE_USED, &linkwatch_flags); |
| 107 | } else { |
| 108 | kfree(event); |
| 109 | } |
| 110 | |
| 111 | /* We are about to handle this device, |
| 112 | * so new events can be accepted |
| 113 | */ |
| 114 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); |
| 115 | |
Stefan Rompf | b00055a | 2006-03-20 17:09:11 -0800 | [diff] [blame] | 116 | rfc2863_policy(dev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | if (dev->flags & IFF_UP) { |
Tommy S. Christensen | cacaddf | 2005-05-03 16:18:52 -0700 | [diff] [blame] | 118 | if (netif_carrier_ok(dev)) { |
| 119 | WARN_ON(dev->qdisc_sleeping == &noop_qdisc); |
| 120 | dev_activate(dev); |
| 121 | } else |
| 122 | dev_deactivate(dev); |
| 123 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | netdev_state_change(dev); |
| 125 | } |
| 126 | |
| 127 | dev_put(dev); |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | |
| 132 | static void linkwatch_event(void *dummy) |
| 133 | { |
| 134 | /* Limit the number of linkwatch events to one |
| 135 | * per second so that a runaway driver does not |
| 136 | * cause a storm of messages on the netlink |
| 137 | * socket |
| 138 | */ |
| 139 | linkwatch_nextevent = jiffies + HZ; |
| 140 | clear_bit(LW_RUNNING, &linkwatch_flags); |
| 141 | |
Stephen Hemminger | 6756ae4 | 2006-03-20 22:23:58 -0800 | [diff] [blame] | 142 | rtnl_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | linkwatch_run_queue(); |
Stephen Hemminger | 6756ae4 | 2006-03-20 22:23:58 -0800 | [diff] [blame] | 144 | rtnl_unlock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | } |
| 146 | |
| 147 | |
| 148 | void linkwatch_fire_event(struct net_device *dev) |
| 149 | { |
| 150 | if (!test_and_set_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { |
| 151 | unsigned long flags; |
| 152 | struct lw_event *event; |
| 153 | |
| 154 | if (test_and_set_bit(LW_SE_USED, &linkwatch_flags)) { |
| 155 | event = kmalloc(sizeof(struct lw_event), GFP_ATOMIC); |
| 156 | |
| 157 | if (unlikely(event == NULL)) { |
| 158 | clear_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state); |
| 159 | return; |
| 160 | } |
| 161 | } else { |
| 162 | event = &singleevent; |
| 163 | } |
| 164 | |
| 165 | dev_hold(dev); |
| 166 | event->dev = dev; |
| 167 | |
| 168 | spin_lock_irqsave(&lweventlist_lock, flags); |
| 169 | list_add_tail(&event->list, &lweventlist); |
| 170 | spin_unlock_irqrestore(&lweventlist_lock, flags); |
| 171 | |
| 172 | if (!test_and_set_bit(LW_RUNNING, &linkwatch_flags)) { |
| 173 | unsigned long thisevent = jiffies; |
| 174 | |
| 175 | if (thisevent >= linkwatch_nextevent) { |
| 176 | schedule_work(&linkwatch_work); |
| 177 | } else { |
| 178 | schedule_delayed_work(&linkwatch_work, linkwatch_nextevent - thisevent); |
| 179 | } |
| 180 | } |
| 181 | } |
| 182 | } |
| 183 | |
| 184 | EXPORT_SYMBOL(linkwatch_fire_event); |