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diff --git a/third_party/libsrtp/src/crypto/include/rdbx.h b/third_party/libsrtp/src/crypto/include/rdbx.h
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+/*
+ * 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 */