Internet on FIRE

/*

 *        BIRD Object Locks

 *

 *        (c) 1999 Martin Mares <mj@ucw.cz>

 *

 *        Can be freely distributed and used under the terms of the GNU GPL.

 */

#ifndef _BIRD_LOCKS_H_

#define _BIRD_LOCKS_H_

#include "lib/resource.h"

#include "lib/event.h"

/*

 *  The object locks are used for controlling exclusive access

 *  to various physical resources like UDP ports on specific devices.

 *  When you want to access such resource, you ask for a object lock

 *  structure, fill in specification of the object and your function

 *  you want to have called when the object is available and invoke

 *  olock_acquire() afterwards. When the object becomes free, the lock

 *  manager calls your function. To free the object lock, just call rfree

 *  on its resource.

 */

struct object_lock {

  resource r;

  ip_addr addr;                /* Identification of a object: IP address */

  uint type;                /* ... object type (OBJLOCK_xxx) */

  uint port;                /* ... port number */

  uint inst;                /* ... instance ID */

  struct iface *iface;        /* ... interface */

  void (*hook)(struct object_lock *);        /* Called when the lock succeeds */

  void *data;                /* User data */

  /* ... internal to lock manager, don't touch ... */

  node n;                /* Node in list of olocks */

  int state;                /* OLOCK_STATE_xxx */

  list waiters;                /* Locks waiting for the same resource */

};

struct object_lock *olock_new(pool *);

void olock_acquire(struct object_lock *);

void olock_init(void);

#define OBJLOCK_UDP 1                        /* UDP port */

#define OBJLOCK_TCP 2                        /* TCP port */

#define OBJLOCK_IP 3                        /* IP protocol */

#define OLOCK_STATE_FREE 0

#define OLOCK_STATE_LOCKED 1

#define OLOCK_STATE_WAITING 2

#define OLOCK_STATE_EVENT 3                /* waiting for unlock processing */

#endif