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Instead of calling custom hooks from object locks, we use standard event sending mechanism to inform protocols about object lock changes. This is a backport from version 3 where these events are passed across threads. This implementation of object locks doesn't use mutexes to lock the whole data structure. In version 3, this data structure may get accessed from multiple threads and must be protected by mutex.
55 lines
1.7 KiB
C
55 lines
1.7 KiB
C
/*
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* BIRD Object Locks
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*
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* (c) 1999 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#ifndef _BIRD_LOCKS_H_
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#define _BIRD_LOCKS_H_
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#include "lib/resource.h"
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#include "lib/event.h"
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/*
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* The object locks are used for controlling exclusive access
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* to various physical resources like UDP ports on specific devices.
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* When you want to access such resource, you ask for a object lock
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* structure, fill in specification of the object and your function
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* you want to have called when the object is available and invoke
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* olock_acquire() afterwards. When the object becomes free, the lock
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* manager calls your function. To free the object lock, just call rfree
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* on its resource.
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*/
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struct object_lock {
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resource r;
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ip_addr addr; /* Identification of a object: IP address */
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uint type; /* ... object type (OBJLOCK_xxx) */
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uint port; /* ... port number */
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uint inst; /* ... instance ID */
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struct iface *iface; /* ... interface */
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struct iface *vrf; /* ... or VRF (if iface is unknown) */
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event event; /* Enqueued when the lock succeeds */
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event_list *target; /* Where to put the event */
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/* ... internal to lock manager, don't touch ... */
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node n; /* Node in list of olocks */
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int state; /* OLOCK_STATE_xxx */
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list waiters; /* Locks waiting for the same resource */
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};
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struct object_lock *olock_new(pool *);
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void olock_acquire(struct object_lock *);
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void olock_init(void);
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#define OBJLOCK_UDP 1 /* UDP port */
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#define OBJLOCK_TCP 2 /* TCP port */
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#define OBJLOCK_IP 3 /* IP protocol */
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#define OLOCK_STATE_FREE 0
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#define OLOCK_STATE_LOCKED 1
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#define OLOCK_STATE_WAITING 2
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#endif
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