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/*
* replay-database.h
*
* interface for a replay database for packet security
*
* David A. McGrew
* Cisco Systems, Inc.
*/
#ifndef REPLAY_DB_H
#define REPLAY_DB_H
#include "integers.h" /* for uint32_t */
#include "datatypes.h" /* for v128_t */
#include "err.h" /* for err_status_t */
/*
* if the ith least significant bit is one, then the packet index
* window_end-i is in the database
*/
typedef struct {
uint32_t window_start; /* packet index of the first bit in bitmask */
v128_t bitmask;
} rdb_t;
#define rdb_bits_in_bitmask (8*sizeof(v128_t))
/*
* rdb init
*
* initalizes rdb
*
* returns err_status_ok on success, err_status_t_fail otherwise
*/
err_status_t
rdb_init(rdb_t *rdb);
/*
* rdb_check
*
* checks to see if index appears in rdb
*
* returns err_status_fail if the index already appears in rdb,
* returns err_status_ok otherwise
*/
err_status_t
rdb_check(const rdb_t *rdb, uint32_t rdb_index);
/*
* rdb_add_index
*
* adds index to rdb_t (and does *not* check if index appears in db)
*
* returns err_status_ok on success, err_status_fail otherwise
*
*/
err_status_t
rdb_add_index(rdb_t *rdb, uint32_t rdb_index);
/*
* the functions rdb_increment() and rdb_get_value() are for use by
* senders, not receivers - DO NOT use these functions on the same
* rdb_t upon which rdb_add_index is used!
*/
/*
* rdb_increment(db) increments the sequence number in db, if it is
* not too high
*
* return values:
*
* err_status_ok no problem
* err_status_key_expired sequence number too high
*
*/
err_status_t
rdb_increment(rdb_t *rdb);
/*
* rdb_get_value(db) returns the current sequence number of db
*/
uint32_t
rdb_get_value(const rdb_t *rdb);
#endif /* REPLAY_DB_H */
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