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Diffstat (limited to 'third_party/libsrtp/src/crypto/include/rdbx.h')
| -rw-r--r-- | third_party/libsrtp/src/crypto/include/rdbx.h | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/third_party/libsrtp/src/crypto/include/rdbx.h b/third_party/libsrtp/src/crypto/include/rdbx.h new file mode 100644 index 0000000000..2194178ee2 --- /dev/null +++ b/third_party/libsrtp/src/crypto/include/rdbx.h @@ -0,0 +1,209 @@ +/* + * rdbx.h + * + * replay database with extended packet indices, using a rollover counter + * + * David A. McGrew + * Cisco Systems, Inc. + * + */ + +/* + * + * Copyright (c) 2001-2017, 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_packet_index(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); + +/* + * srtp_rdbx_get_roc(rdbx) + * + * Get the current rollover counter + * + */ +uint32_t srtp_rdbx_get_roc(const srtp_rdbx_t *rdbx); + +/* + * srtp_rdbx_set_roc_seq(rdbx, roc, seq) initalizes the srtp_rdbx_t at the + * location rdbx to have the rollover counter value roc and packet sequence + * number seq. If the new rollover counter 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_seq(srtp_rdbx_t *rdbx, + uint32_t roc, + uint16_t seq); + +#ifdef __cplusplus +} +#endif + +#endif /* RDBX_H */ |