| /* |
| * rdbx.h |
| * |
| * replay database with extended packet indices, using a rollover counter |
| * |
| * David A. McGrew |
| * Cisco Systems, Inc. |
| * |
| */ |
| |
| /* |
| * |
| * Copyright (c) 2001-2006, Cisco Systems, Inc. |
| * All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * Redistributions in binary form must reproduce the above |
| * copyright notice, this list of conditions and the following |
| * disclaimer in the documentation and/or other materials provided |
| * with the distribution. |
| * |
| * Neither the name of the Cisco Systems, Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived |
| * from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, |
| * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
| * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR |
| * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, |
| * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED |
| * OF THE POSSIBILITY OF SUCH DAMAGE. |
| * |
| */ |
| |
| #ifndef RDBX_H |
| #define RDBX_H |
| |
| #include "datatypes.h" |
| #include "err.h" |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /* #define ROC_TEST */ |
| |
| #ifndef ROC_TEST |
| |
| typedef uint16_t srtp_sequence_number_t; /* 16 bit sequence number */ |
| typedef uint32_t srtp_rollover_counter_t; /* 32 bit rollover counter */ |
| |
| #else /* use small seq_num and roc datatypes for testing purposes */ |
| |
| typedef unsigned char srtp_sequence_number_t; /* 8 bit sequence number */ |
| typedef uint16_t srtp_rollover_counter_t; /* 16 bit rollover counter */ |
| |
| #endif |
| |
| #define seq_num_median (1 << (8 * sizeof(srtp_sequence_number_t) - 1)) |
| #define seq_num_max (1 << (8 * sizeof(srtp_sequence_number_t))) |
| |
| /* |
| * An rtp_xtd_seq_num_t is a 64-bit unsigned integer used as an 'extended' |
| * sequence number. |
| */ |
| typedef uint64_t srtp_xtd_seq_num_t; |
| |
| |
| /* |
| * An srtp_rdbx_t is a replay database with extended range; it uses an |
| * xtd_seq_num_t and a bitmask of recently received indices. |
| */ |
| typedef struct { |
| srtp_xtd_seq_num_t index; |
| bitvector_t bitmask; |
| } srtp_rdbx_t; |
| |
| |
| /* |
| * srtp_rdbx_init(rdbx_ptr, ws) |
| * |
| * initializes the rdbx pointed to by its argument with the window size ws, |
| * setting the rollover counter and sequence number to zero |
| */ |
| srtp_err_status_t srtp_rdbx_init(srtp_rdbx_t *rdbx, unsigned long ws); |
| |
| |
| /* |
| * srtp_rdbx_dealloc(rdbx_ptr) |
| * |
| * frees memory associated with the rdbx |
| */ |
| srtp_err_status_t srtp_rdbx_dealloc(srtp_rdbx_t *rdbx); |
| |
| |
| /* |
| * srtp_rdbx_estimate_index(rdbx, guess, s) |
| * |
| * given an rdbx and a sequence number s (from a newly arrived packet), |
| * sets the contents of *guess to contain the best guess of the packet |
| * index to which s corresponds, and returns the difference between |
| * *guess and the locally stored synch info |
| */ |
| int32_t srtp_rdbx_estimate_index(const srtp_rdbx_t *rdbx, srtp_xtd_seq_num_t *guess, srtp_sequence_number_t s); |
| |
| /* |
| * srtp_rdbx_check(rdbx, delta); |
| * |
| * srtp_rdbx_check(&r, delta) checks to see if the xtd_seq_num_t |
| * which is at rdbx->window_start + delta is in the rdb |
| * |
| */ |
| srtp_err_status_t srtp_rdbx_check(const srtp_rdbx_t *rdbx, int difference); |
| |
| /* |
| * srtp_replay_add_index(rdbx, delta) |
| * |
| * adds the srtp_xtd_seq_num_t at rdbx->window_start + delta to replay_db |
| * (and does *not* check if that xtd_seq_num_t appears in db) |
| * |
| * this function should be called *only* after replay_check has |
| * indicated that the index does not appear in the rdbx, and a mutex |
| * should protect the rdbx between these calls if necessary. |
| */ |
| srtp_err_status_t srtp_rdbx_add_index(srtp_rdbx_t *rdbx, int delta); |
| |
| |
| /* |
| * srtp_rdbx_set_roc(rdbx, roc) initalizes the srtp_rdbx_t at the location rdbx |
| * to have the rollover counter value roc. If that value is less than |
| * the current rollover counter value, then the function returns |
| * srtp_err_status_replay_old; otherwise, srtp_err_status_ok is returned. |
| * |
| */ |
| srtp_err_status_t srtp_rdbx_set_roc(srtp_rdbx_t *rdbx, uint32_t roc); |
| |
| /* |
| * srtp_rdbx_get_roc(rdbx) returns the value of the rollover counter for |
| * the srtp_rdbx_t pointed to by rdbx |
| * |
| */ |
| srtp_xtd_seq_num_t srtp_rdbx_get_packet_index(const srtp_rdbx_t *rdbx); |
| |
| /* |
| * srtp_xtd_seq_num_t functions - these are *internal* functions of rdbx, and |
| * shouldn't be used to manipulate rdbx internal values. use the rdbx |
| * api instead! |
| */ |
| |
| /* |
| * srtp_rdbx_get_ws(rdbx_ptr) |
| * |
| * gets the window size which was used to initialize the rdbx |
| */ |
| unsigned long srtp_rdbx_get_window_size(const srtp_rdbx_t *rdbx); |
| |
| |
| /* index_init(&pi) initializes a packet index pi (sets it to zero) */ |
| void srtp_index_init(srtp_xtd_seq_num_t *pi); |
| |
| /* index_advance(&pi, s) advances a xtd_seq_num_t forward by s */ |
| void srtp_index_advance(srtp_xtd_seq_num_t *pi, srtp_sequence_number_t s); |
| |
| |
| /* |
| * srtp_index_guess(local, guess, s) |
| * |
| * given a srtp_xtd_seq_num_t local (which represents the highest |
| * known-to-be-good index) and a sequence number s (from a newly |
| * arrived packet), sets the contents of *guess to contain the best |
| * guess of the packet index to which s corresponds, and returns the |
| * difference between *guess and *local |
| */ |
| int32_t srtp_index_guess(const srtp_xtd_seq_num_t *local, srtp_xtd_seq_num_t *guess, srtp_sequence_number_t s); |
| |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* RDBX_H */ |