/*
   * A security identifier table (sidtab) is a hash table
   * of security context structures indexed by SID value.
   *
   * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
   */
  #ifndef _SS_SIDTAB_H_
  #define _SS_SIDTAB_H_
  
  #include "context.h"
  
  struct sidtab_node {
  	u32 sid;		/* security identifier */
  	struct context context;	/* security context structure */
  	struct sidtab_node *next;
  };
  
  #define SIDTAB_HASH_BITS 7
  #define SIDTAB_HASH_BUCKETS (1 << SIDTAB_HASH_BITS)
  #define SIDTAB_HASH_MASK (SIDTAB_HASH_BUCKETS-1)
  
  #define SIDTAB_SIZE SIDTAB_HASH_BUCKETS
  
  struct sidtab {
  	struct sidtab_node **htable;
  	unsigned int nel;	/* number of elements */
  	unsigned int next_sid;	/* next SID to allocate */
  	unsigned char shutdown;

  #define SIDTAB_CACHE_LEN	3
  	struct sidtab_node *cache[SIDTAB_CACHE_LEN];

  	spinlock_t lock;
  };
  
  int sidtab_init(struct sidtab *s);
  int sidtab_insert(struct sidtab *s, u32 sid, struct context *context);
  struct context *sidtab_search(struct sidtab *s, u32 sid);

  struct context *sidtab_search_force(struct sidtab *s, u32 sid);

  
  int sidtab_map(struct sidtab *s,
  	       int (*apply) (u32 sid,
  			     struct context *context,
  			     void *args),
  	       void *args);

  int sidtab_context_to_sid(struct sidtab *s,
  			  struct context *context,
  			  u32 *sid);
  
  void sidtab_hash_eval(struct sidtab *h, char *tag);
  void sidtab_destroy(struct sidtab *s);
  void sidtab_set(struct sidtab *dst, struct sidtab *src);
  void sidtab_shutdown(struct sidtab *s);
  
  #endif	/* _SS_SIDTAB_H_ */