nest/locks.h

   1 /*
   2  *      BIRD Object Locks
   3  *
   4  *      (c) 1999 Martin Mares <mj@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL.
   7  */
   8
   9 #ifndef _BIRD_LOCKS_H_
  10 #define _BIRD_LOCKS_H_
  11
  12 #include "lib/resource.h"
  13 #include "lib/event.h"
  14
  15 /*
  16  *  The object locks are used for controlling exclusive access
  17  *  to various physical resources like UDP ports on specific devices.
  18  *  When you want to access such resource, you ask for a object lock
  19  *  structure, fill in specification of the object and your function
  20  *  you want to have called when the object is available and invoke
  21  *  olock_acquire() afterwards. When the object becomes free, the lock
  22  *  manager calls your function. To free the object lock, just call rfree
  23  *  on its resource.
  24  */
  25
  26 struct object_lock {
  27   resource r;
  28   ip_addr addr;         /* Identification of a object: IP address */
  29   uint type;            /* ... object type (OBJLOCK_xxx) */
  30   uint port;            /* ... port number */
  31   uint inst;            /* ... instance ID */
  32   struct iface *iface;  /* ... interface */
  33   struct iface *vrf;    /* ... or VRF (if iface is unknown) */
  34   void (*hook)(struct object_lock *);   /* Called when the lock succeeds */
  35   void *data;           /* User data */
  36   /* ... internal to lock manager, don't touch ... */
  37   node n;               /* Node in list of olocks */
  38   int state;            /* OLOCK_STATE_xxx */
  39   list waiters;         /* Locks waiting for the same resource */
  40 };
  41
  42 struct object_lock *olock_new(pool *);
  43 void olock_acquire(struct object_lock *);
  44 void olock_init(void);
  45
  46 #define OBJLOCK_UDP 1                   /* UDP port */
  47 #define OBJLOCK_TCP 2                   /* TCP port */
  48 #define OBJLOCK_IP 3                    /* IP protocol */
  49
  50 #define OLOCK_STATE_FREE 0
  51 #define OLOCK_STATE_LOCKED 1
  52 #define OLOCK_STATE_WAITING 2
  53 #define OLOCK_STATE_EVENT 3             /* waiting for unlock processing */
  54
  55 #endif