The Tor Browser: comparison netwerk/srtp/src/crypto/include/rdbx.h

--1:000000000000
+:aec040eafa12
+/*
+* 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"
+/* #define ROC_TEST */
+#ifndef ROC_TEST
+typedef uint16_t sequence_number_t;   /* 16 bit sequence number  */
+typedef uint32_t rollover_counter_t;   /* 32 bit rollover counter */
+#else  /* use small seq_num and roc datatypes for testing purposes */
+typedef unsigned char sequence_number_t;         /* 8 bit sequence number   */
+typedef uint16_t rollover_counter_t;   /* 16 bit rollover counter */
+#endif
+#define seq_num_median (1 << (8*sizeof(sequence_number_t) - 1))
+#define seq_num_max    (1 << (8*sizeof(sequence_number_t)))
+/*
+* An xtd_seq_num_t is a 64-bit unsigned integer used as an 'extended'
+* sequence number.
+*/
+typedef uint64_t xtd_seq_num_t;
+/*
+* An 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 {
+xtd_seq_num_t index;
+bitvector_t bitmask;
+} rdbx_t;
+/*
+* 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
+*/
+err_status_t
+rdbx_init(rdbx_t *rdbx, unsigned long ws);
+/*
+* rdbx_dealloc(rdbx_ptr)
+*
+* frees memory associated with the rdbx
+*/
+err_status_t
+rdbx_dealloc(rdbx_t *rdbx);
+/*
+* 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
+*/
+int
+rdbx_estimate_index(const rdbx_t *rdbx,
+		    xtd_seq_num_t *guess,
+		    sequence_number_t s);
+/*
+* rdbx_check(rdbx, delta);
+*
+* rdbx_check(&r, delta) checks to see if the xtd_seq_num_t
+* which is at rdbx->window_start + delta is in the rdb
+*
+*/
+err_status_t
+rdbx_check(const rdbx_t *rdbx, int difference);
+/*
+* replay_add_index(rdbx, delta)
+*
+* adds the 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.
+*/
+err_status_t
+rdbx_add_index(rdbx_t *rdbx, int delta);
+/*
+* rdbx_set_roc(rdbx, roc) initalizes the 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
+* err_status_replay_old; otherwise, err_status_ok is returned.
+*
+*/
+err_status_t
+rdbx_set_roc(rdbx_t *rdbx, uint32_t roc);
+/*
+* rdbx_get_roc(rdbx) returns the value of the rollover counter for
+* the rdbx_t pointed to by rdbx
+*
+*/
+xtd_seq_num_t
+rdbx_get_packet_index(const rdbx_t *rdbx);
+/*
+* 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!
+*/
+/*
+* rdbx_get_ws(rdbx_ptr)
+*
+* gets the window size which was used to initialize the rdbx
+*/
+unsigned long
+rdbx_get_window_size(const rdbx_t *rdbx);
+/* index_init(&pi) initializes a packet index pi (sets it to zero) */
+void
+index_init(xtd_seq_num_t *pi);
+/* index_advance(&pi, s) advances a xtd_seq_num_t forward by s */
+void
+index_advance(xtd_seq_num_t *pi, sequence_number_t s);
+/*
+* index_guess(local, guess, s)
+*
+* given a 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
+*/
+int
+index_guess(const xtd_seq_num_t *local,
+		   xtd_seq_num_t *guess,
+		   sequence_number_t s);
+#endif /* RDBX_H */

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comparison: netwerk/srtp/src/crypto/include/rdbx.h

netwerk/srtp/src/crypto/include/rdbx.h