1 #ifndef REPLAY_PROTECTION_H 2 #define REPLAY_PROTECTION_H 3 4 #include <stdint.h> 5 #include <stdbool.h> 6 7 #include "common/oscore_edhoc_error.h" 8 #include "common/byte_array.h" 9 10 /* Replay window size - it can be defined by the user here or outside of this file. */ 11 /* NOTE: window size of 32 is the MINUMUM that is RFC-compliant. */ 12 #ifndef OSCORE_SERVER_REPLAY_WINDOW_SIZE 13 #define OSCORE_SERVER_REPLAY_WINDOW_SIZE 32 14 #endif 15 16 /* Replay window structure, used internally. */ 17 struct server_replay_window_t { 18 uint64_t window[OSCORE_SERVER_REPLAY_WINDOW_SIZE]; 19 bool seq_num_zero_received; /* helper flag used for validation of sequence number 0 */ 20 }; 21 22 /** 23 * @brief Initialize given replay window with default values. 24 * 25 * @param replay_window [out] a pointer to replay window structure 26 * @return err 27 */ 28 enum err server_replay_window_init(struct server_replay_window_t *replay_window); 29 30 /** 31 * @brief Re-initialize given replay window based on current sequence number. 32 * 33 * This could be used by the user to restore the session. 34 * After restoring, replay protection will reject any packet with sequence number 35 * that is not greater than the one provided in the argument. 36 * 37 * @param current_sequence_number [in] last sequence number that was received before the session was stored 38 * @param replay_window [out] a pointer to replay window structure 39 * @return err 40 */ 41 enum err server_replay_window_reinit(uint64_t current_sequence_number, 42 struct server_replay_window_t *replay_window); 43 44 /** 45 * @brief Check whether given sequence number is valid in terms of server replay protection. 46 * 47 * @param seq_number [in] sequence number of the message received by the server 48 * @param replay_window [in] a pointer to replay window structure 49 * @return true if ok, false otherwise 50 */ 51 bool server_is_sequence_number_valid(uint64_t seq_number, 52 struct server_replay_window_t *replay_window); 53 54 /** 55 * @brief Update given replay window with last received sequence number. 56 * 57 * @param seq_number [in] sequence number of the message received by the server 58 * @param replay_window [out] a pointer to replay window structure 59 * @return true if ok, false if sequence number is not valid (this indicates that calling function hasn't check the sequence number before) 60 */ 61 bool server_replay_window_update(uint64_t seq_number, 62 struct server_replay_window_t *replay_window); 63 64 /** 65 * @brief Checks if an notification is replayed 66 * @param notification_num the notification number 67 * @param notification_num_initialized flag used to indicated if the 68 * notification number was initialized 69 * @param piv the PIV 70 * @retval error code or ok 71 */ 72 enum err replay_protection_check_notification(uint64_t notification_num, 73 bool notification_num_initialized, 74 struct byte_array *piv); 75 76 /** 77 * @brief Updates the notification number with value of the PIV 78 * @param notification_num pointer to the notification number 79 * @param notification_num_initialized flag used to indicated if the 80 * notification number was initialized 81 * @param piv the PIV 82 * @retval error code or ok 83 */ 84 enum err notification_number_update(uint64_t *notification_num, 85 bool *notification_num_initialized, 86 struct byte_array *piv); 87 #endif 88
