#ifndef _FS_CEPH_AUTH_H
  #define _FS_CEPH_AUTH_H

  #include <linux/ceph/types.h>
  #include <linux/ceph/buffer.h>

  
  /*
   * Abstract interface for communicating with the authenticate module.
   * There is some handshake that takes place between us and the monitor
   * to acquire the necessary keys.  These are used to generate an
   * 'authorizer' that we use when connecting to a service (mds, osd).
   */
  
  struct ceph_auth_client;
  struct ceph_authorizer;
  
  struct ceph_auth_client_ops {

  	const char *name;

  	/*
  	 * true if we are authenticated and can connect to
  	 * services.
  	 */
  	int (*is_authenticated)(struct ceph_auth_client *ac);
  
  	/*

  	 * true if we should (re)authenticate, e.g., when our tickets
  	 * are getting old and crusty.
  	 */
  	int (*should_authenticate)(struct ceph_auth_client *ac);
  
  	/*

  	 * build requests and process replies during monitor
  	 * handshake.  if handle_reply returns -EAGAIN, we build
  	 * another request.
  	 */
  	int (*build_request)(struct ceph_auth_client *ac, void *buf, void *end);
  	int (*handle_reply)(struct ceph_auth_client *ac, int result,
  			    void *buf, void *end);
  
  	/*
  	 * Create authorizer for connecting to a service, and verify
  	 * the response to authenticate the service.
  	 */
  	int (*create_authorizer)(struct ceph_auth_client *ac, int peer_type,
  				 struct ceph_authorizer **a,
  				 void **buf, size_t *len,
  				 void **reply_buf, size_t *reply_len);
  	int (*verify_authorizer_reply)(struct ceph_auth_client *ac,
  				       struct ceph_authorizer *a, size_t len);
  	void (*destroy_authorizer)(struct ceph_auth_client *ac,
  				   struct ceph_authorizer *a);

  	void (*invalidate_authorizer)(struct ceph_auth_client *ac,
  				      int peer_type);

  
  	/* reset when we (re)connect to a monitor */
  	void (*reset)(struct ceph_auth_client *ac);
  
  	void (*destroy)(struct ceph_auth_client *ac);
  };
  
  struct ceph_auth_client {
  	u32 protocol;           /* CEPH_AUTH_* */
  	void *private;          /* for use by protocol implementation */
  	const struct ceph_auth_client_ops *ops;  /* null iff protocol==0 */
  
  	bool negotiating;       /* true if negotiating protocol */
  	const char *name;       /* entity name */
  	u64 global_id;          /* our unique id in system */

  	const struct ceph_crypto_key *key;     /* our secret key */

  	unsigned want_keys;     /* which services we want */
  };
  
  extern struct ceph_auth_client *ceph_auth_init(const char *name,

  					       const struct ceph_crypto_key *key);

  extern void ceph_auth_destroy(struct ceph_auth_client *ac);
  
  extern void ceph_auth_reset(struct ceph_auth_client *ac);
  
  extern int ceph_auth_build_hello(struct ceph_auth_client *ac,
  				 void *buf, size_t len);
  extern int ceph_handle_auth_reply(struct ceph_auth_client *ac,
  				  void *buf, size_t len,
  				  void *reply_buf, size_t reply_len);
  extern int ceph_entity_name_encode(const char *name, void **p, void *end);

  extern int ceph_build_auth(struct ceph_auth_client *ac,
  		    void *msg_buf, size_t msg_len);
  
  extern int ceph_auth_is_authenticated(struct ceph_auth_client *ac);

  #endif