| 1 | /*
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| 2 | * Routines to manage notifier chains for passing status changes to any
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| 3 | * interested routines. We need this instead of hard coded call lists so
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| 4 | * that modules can poke their nose into the innards. The network devices
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| 5 | * needed them so here they are for the rest of you.
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| 6 | *
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| 7 | * Alan Cox <Alan.Cox@linux.org>
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| 8 | */
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| 9 |
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| 10 | #ifndef _LINUX_NOTIFIER_H
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| 11 | #define _LINUX_NOTIFIER_H
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| 12 | #include <linux/errno.h>
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| 13 |
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| 14 | struct notifier_block
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| 15 | {
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| 16 | int (*notifier_call)(struct notifier_block *self, unsigned long, void *);
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| 17 | struct notifier_block *next;
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| 18 | int priority;
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| 19 | };
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| 20 |
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| 21 |
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| 22 | #ifdef __KERNEL__
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| 23 |
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| 24 | #define NOTIFY_DONE 0x0000 /* Don't care */
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| 25 | #define NOTIFY_OK 0x0001 /* Suits me */
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| 26 | #define NOTIFY_STOP_MASK 0x8000 /* Don't call further */
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| 27 | #define NOTIFY_BAD (NOTIFY_STOP_MASK|0x0002) /* Bad/Veto action */
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| 28 |
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| 29 | extern __inline__ int notifier_chain_register(struct notifier_block **list, struct notifier_block *n)
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| 30 | {
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| 31 | while(*list)
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| 32 | {
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| 33 | if(n->priority > (*list)->priority)
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| 34 | break;
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| 35 | list= &((*list)->next);
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| 36 | }
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| 37 | n->next = *list;
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| 38 | *list=n;
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| 39 | return 0;
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| 40 | }
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| 41 |
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| 42 | /*
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| 43 | * Warning to any non GPL module writers out there.. these functions are
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| 44 | * GPL'd
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| 45 | */
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| 46 |
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| 47 | extern __inline__ int notifier_chain_unregister(struct notifier_block **nl, struct notifier_block *n)
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| 48 | {
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| 49 | while((*nl)!=NULL)
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| 50 | {
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| 51 | if((*nl)==n)
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| 52 | {
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| 53 | *nl=n->next;
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| 54 | return 0;
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| 55 | }
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| 56 | nl=&((*nl)->next);
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| 57 | }
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| 58 | return -ENOENT;
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| 59 | }
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| 60 |
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| 61 | /*
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| 62 | * This is one of these things that is generally shorter inline
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| 63 | */
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| 64 |
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| 65 | extern __inline__ int notifier_call_chain(struct notifier_block **n, unsigned long val, void *v)
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| 66 | {
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| 67 | int ret=NOTIFY_DONE;
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| 68 | struct notifier_block *nb = *n;
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| 69 | while(nb)
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| 70 | {
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| 71 | ret=nb->notifier_call(nb,val,v);
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| 72 | if(ret&NOTIFY_STOP_MASK)
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| 73 | return ret;
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| 74 | nb=nb->next;
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| 75 | }
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| 76 | return ret;
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| 77 | }
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| 78 |
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| 79 |
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| 80 | /*
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| 81 | * Declared notifiers so far. I can imagine quite a few more chains
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| 82 | * over time (eg laptop power reset chains, reboot chain (to clean
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| 83 | * device units up), device [un]mount chain, module load/unload chain,
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| 84 | * low memory chain, screenblank chain (for plug in modular screenblankers)
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| 85 | * VC switch chains (for loadable kernel svgalib VC switch helpers) etc...
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| 86 | */
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| 87 |
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| 88 | /* netdevice notifier chain */
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| 89 | #define NETDEV_UP 0x0001 /* For now you can't veto a device up/down */
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| 90 | #define NETDEV_DOWN 0x0002
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| 91 | #define NETDEV_REBOOT 0x0003 /* Tell a protocol stack a network interface
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| 92 | detected a hardware crash and restarted
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| 93 | - we can use this eg to kick tcp sessions
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| 94 | once done */
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| 95 | #define NETDEV_CHANGE 0x0004 /* Notify device state change */
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| 96 | #define NETDEV_REGISTER 0x0005
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| 97 | #define NETDEV_UNREGISTER 0x0006
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| 98 | #define NETDEV_CHANGEMTU 0x0007
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| 99 | #define NETDEV_CHANGEADDR 0x0008
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| 100 | #define NETDEV_GOING_DOWN 0x0009
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| 101 | #define NETDEV_CHANGENAME 0x000A
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| 102 |
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| 103 | #define SYS_DOWN 0x0001 /* Notify of system down */
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| 104 | #define SYS_RESTART SYS_DOWN
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| 105 | #define SYS_HALT 0x0002 /* Notify of system halt */
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| 106 | #define SYS_POWER_OFF 0x0003 /* Notify of system power off */
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| 107 |
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| 108 | /*
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| 109 | * Publically visible notifier objects
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| 110 | */
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| 111 |
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| 112 | extern struct notifier_block *boot_notifier_list;
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| 113 |
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| 114 | #endif
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| 115 | #endif
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