1/*
2 * replay-database.h
3 *
4 * interface for a replay database for packet security
5 *
6 * David A. McGrew
7 * Cisco Systems, Inc.
8 */
9
10
11#ifndef REPLAY_DB_H
12#define REPLAY_DB_H
13
14#include "integers.h"         /* for uint32_t     */
15#include "datatypes.h"        /* for v128_t       */
16#include "err.h"              /* for err_status_t */
17
18/*
19 * if the ith least significant bit is one, then the packet index
20 * window_end-i is in the database
21 */
22
23typedef struct {
24  uint32_t window_start;   /* packet index of the first bit in bitmask */
25  v128_t bitmask;
26} rdb_t;
27
28#define rdb_bits_in_bitmask (8*sizeof(v128_t))
29
30/*
31 * rdb init
32 *
33 * initalizes rdb
34 *
35 * returns err_status_ok on success, err_status_t_fail otherwise
36 */
37
38err_status_t
39rdb_init(rdb_t *rdb);
40
41
42/*
43 * rdb_check
44 *
45 * checks to see if index appears in rdb
46 *
47 * returns err_status_fail if the index already appears in rdb,
48 * returns err_status_ok otherwise
49 */
50
51err_status_t
52rdb_check(const rdb_t *rdb, uint32_t index);
53
54/*
55 * rdb_add_index
56 *
57 * adds index to rdb_t (and does *not* check if index appears in db)
58 *
59 * returns err_status_ok on success, err_status_fail otherwise
60 *
61 */
62
63err_status_t
64rdb_add_index(rdb_t *rdb, uint32_t index);
65
66/*
67 * the functions rdb_increment() and rdb_get_value() are for use by
68 * senders, not receivers - DO NOT use these functions on the same
69 * rdb_t upon which rdb_add_index is used!
70 */
71
72
73/*
74 * rdb_increment(db) increments the sequence number in db, if it is
75 * not too high
76 *
77 * return values:
78 *
79 *    err_status_ok            no problem
80 *    err_status_key_expired   sequence number too high
81 *
82 */
83err_status_t
84rdb_increment(rdb_t *rdb);
85
86/*
87 * rdb_get_value(db) returns the current sequence number of db
88 */
89
90uint32_t
91rdb_get_value(const rdb_t *rdb);
92
93
94#endif /* REPLAY_DB_H */
95