Adding upstream version 86.0.1.upstream/86.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

6 files changed, 2376 insertions, 0 deletions

diff --git a/netwerk/srtp/src/include/config.h b/netwerk/srtp/src/include/config.h
new file mode 100644
index 0000000000..75e05e897f
--- /dev/null
+++ b/netwerk/srtp/src/include/config.h
@@ -0,0 +1,6 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+/* empty file; config done via Makefile.in & configure.in */
diff --git a/netwerk/srtp/src/include/ekt.h b/netwerk/srtp/src/include/ekt.h
new file mode 100644
index 0000000000..a289a53dab
--- /dev/null
+++ b/netwerk/srtp/src/include/ekt.h
@@ -0,0 +1,181 @@
+/*
+ * ekt.h
+ *
+ * interface to Encrypted Key Transport for SRTP
+ *
+ * David 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.
+ *
+ */
+
+/*
+ * EKT implementation strategy
+ *
+ * use stream_template approach
+ *
+ * in srtp_unprotect, when a new stream appears, check if template has
+ * EKT defined, and if it does, then apply EKT processing
+ *
+ * question: will we want to allow key-sharing templates in addition
+ * to EKT templates?  could define a new ssrc_type_t that's associated
+ * with an EKT, e.g.  ssrc_any_ekt.
+ *
+ *
+ */
+
+#ifndef SRTP_EKT_H
+#define SRTP_EKT_H
+
+// left in commented out as reminder to not include private headers
+//#include "srtp_priv.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SRTP_EKT_CIPHER_DEFAULT 1
+#define SRTP_EKT_CIPHER_AES_128_ECB 1
+#define SRTP_EKT_CIPHER_AES_192_KEY_WRAP 2
+#define SRTP_EKT_CIPHER_AES_256_KEY_WRAP 3
+
+typedef uint16_t srtp_ekt_spi_t;
+
+unsigned srtp_ekt_octets_after_base_tag(srtp_ekt_stream_t ekt);
+
+/*
+ * an srtp_policy_t structure can contain a pointer to an
+ * srtp_ekt_policy_t structure
+ *
+ * this structure holds all of the high level EKT information, and it
+ * is passed into libsrtp to indicate what policy should be in effect
+ */
+
+typedef struct srtp_ekt_policy_ctx_t {
+    srtp_ekt_spi_t spi; /* security parameter index */
+    uint8_t ekt_cipher_type;
+    uint8_t *ekt_key;
+    struct srtp_ekt_policy_ctx_t *next_ekt_policy;
+} srtp_ekt_policy_ctx_t;
+
+/*
+ * an srtp_ekt_data_t structure holds the data corresponding to an ekt key,
+ * spi, and so on
+ */
+
+typedef struct srtp_ekt_data_t {
+    srtp_ekt_spi_t spi;
+    uint8_t ekt_cipher_type;
+    srtp_aes_expanded_key_t ekt_enc_key;
+    srtp_aes_expanded_key_t ekt_dec_key;
+    struct ekt_data_t *next_ekt_data;
+} srtp_ekt_data_t;
+
+/*
+ * an srtp_stream_ctx_t can contain an srtp_ekt_stream_ctx_t
+ *
+ * an srtp_ekt_stream_ctx_t structure holds all of the EKT information for
+ * a specific SRTP stream
+ */
+
+typedef struct srtp_ekt_stream_ctx_t {
+    srtp_ekt_data_t *data;
+    uint16_t isn; /* initial sequence number  */
+    uint8_t encrypted_master_key[SRTP_MAX_KEY_LEN];
+} srtp_ekt_stream_ctx_t;
+
+srtp_err_status_t srtp_ekt_alloc(srtp_ekt_stream_t *stream_data,
+                                 srtp_ekt_policy_t policy);
+
+srtp_err_status_t srtp_ekt_stream_init(srtp_ekt_stream_t e,
+                                       srtp_ekt_spi_t spi,
+                                       void *ekt_key,
+                                       unsigned ekt_cipher_type);
+
+srtp_err_status_t srtp_ekt_stream_init_from_policy(srtp_ekt_stream_t e,
+                                                   srtp_ekt_policy_t p);
+
+srtp_err_status_t srtp_stream_init_from_ekt(srtp_stream_t stream,
+                                            const void *srtcp_hdr,
+                                            unsigned pkt_octet_len);
+
+void srtp_ekt_write_data(srtp_ekt_stream_t ekt,
+                         uint8_t *base_tag,
+                         unsigned base_tag_len,
+                         int *packet_len,
+                         srtp_xtd_seq_num_t pkt_index);
+
+/*
+ * We handle EKT by performing some additional steps before
+ * authentication (copying the auth tag into a temporary location,
+ * zeroizing the "base tag" field in the packet)
+ *
+ * With EKT, the tag_len parameter is actually the base tag
+ * length
+ */
+srtp_err_status_t srtp_ekt_tag_verification_preproces(uint8_t *pkt_tag,
+                                                      uint8_t *pkt_tag_copy,
+                                                      unsigned tag_len);
+
+srtp_err_status_t srtp_ekt_tag_verification_postproces(uint8_t *pkt_tag,
+                                                       uint8_t *pkt_tag_copy,
+                                                       unsigned tag_len);
+
+/*
+ * @brief EKT pre-processing for srtcp tag generation
+ *
+ * This function does the pre-processing of the SRTCP authentication
+ * tag format.  When EKT is used, it consists of writing the Encrypted
+ * Master Key, the SRTP ROC, the Initial Sequence Number, and SPI
+ * fields.  The Base Authentication Tag field is set to the all-zero
+ * value
+ *
+ * When EKT is not used, this function is a no-op.
+ *
+ */
+srtp_err_status_t srtp_stream_srtcp_auth_tag_generation_preprocess(
+    const srtp_stream_t *s,
+    uint8_t *pkt_tag,
+    unsigned pkt_octet_len);
+
+/* it's not clear that a tag_generation_postprocess function is needed */
+srtp_err_status_t srtcp_auth_tag_generation_postprocess(void);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SRTP_EKT_H */
diff --git a/netwerk/srtp/src/include/getopt_s.h b/netwerk/srtp/src/include/getopt_s.h
new file mode 100644
index 0000000000..53fb25ba71
--- /dev/null
+++ b/netwerk/srtp/src/include/getopt_s.h
@@ -0,0 +1,67 @@
+/*
+ * getopt.h
+ *
+ * interface to a minimal implementation of the getopt() function,
+ * written so that test applications that use that function can run on
+ * non-POSIX platforms
+ *
+ */
+/*
+ *
+ * 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 GETOPT_S_H
+#define GETOPT_S_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * getopt_s(), optarg_s, and optind_s are small, locally defined
+ * versions of the POSIX standard getopt() interface.
+ */
+
+int getopt_s(int argc, char *const argv[], const char *optstring);
+
+extern char *optarg_s; /* defined in getopt.c */
+
+extern int optind_s; /* defined in getopt.c */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* GETOPT_S_H */
diff --git a/netwerk/srtp/src/include/srtp.h b/netwerk/srtp/src/include/srtp.h
new file mode 100644
index 0000000000..1fdd6c3aff
--- /dev/null
+++ b/netwerk/srtp/src/include/srtp.h
@@ -0,0 +1,1759 @@
+/*
+ * srtp.h
+ *
+ * interface to libsrtp
+ *
+ * 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 SRTP_SRTP_H
+#define SRTP_SRTP_H
+
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @defgroup SRTP Secure RTP
+ *
+ * @brief libSRTP provides functions for protecting RTP and RTCP.  See
+ * Section @ref Overview for an introduction to the use of the library.
+ *
+ * @{
+ */
+
+/*
+ * SRTP_MASTER_KEY_LEN is the nominal master key length supported by libSRTP
+ */
+
+#define SRTP_MASTER_KEY_LEN 30
+
+/*
+ * SRTP_MAX_KEY_LEN is the maximum key length supported by libSRTP
+ */
+#define SRTP_MAX_KEY_LEN 64
+
+/*
+ * SRTP_MAX_TAG_LEN is the maximum tag length supported by libSRTP
+ */
+
+#define SRTP_MAX_TAG_LEN 16
+
+/**
+ * SRTP_MAX_MKI_LEN is the maximum size the MKI could be which is
+ * 128 bytes
+ */
+#define SRTP_MAX_MKI_LEN 128
+
+/**
+ * SRTP_MAX_TRAILER_LEN is the maximum length of the SRTP trailer
+ * (authentication tag and MKI) supported by libSRTP.  This value is
+ * the maixmum number of octets that will be added to an RTP packet by
+ * srtp_protect().
+ *
+ * @brief the maximum number of octets added by srtp_protect().
+ */
+#define SRTP_MAX_TRAILER_LEN (SRTP_MAX_TAG_LEN + SRTP_MAX_MKI_LEN)
+
+/**
+ * SRTP_MAX_NUM_MASTER_KEYS is the maximum number of Master keys for
+ * MKI supported by libSRTP.
+ *
+ */
+#define SRTP_MAX_NUM_MASTER_KEYS 16
+
+#define SRTP_SALT_LEN 14
+
+/*
+ * SRTP_AEAD_SALT_LEN is the length of the SALT values used with
+ * GCM mode.  GCM mode requires an IV.  The SALT value is used
+ * as part of the IV formation logic applied to each RTP packet.
+ */
+#define SRTP_AEAD_SALT_LEN 12
+
+#define SRTP_AES_128_KEY_LEN 16
+#define SRTP_AES_192_KEY_LEN 24
+#define SRTP_AES_256_KEY_LEN 32
+
+#define SRTP_AES_ICM_128_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_128_KEY_LEN)
+#define SRTP_AES_ICM_192_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_192_KEY_LEN)
+#define SRTP_AES_ICM_256_KEY_LEN_WSALT (SRTP_SALT_LEN + SRTP_AES_256_KEY_LEN)
+
+#define SRTP_AES_GCM_128_KEY_LEN_WSALT                                         \
+    (SRTP_AEAD_SALT_LEN + SRTP_AES_128_KEY_LEN)
+#define SRTP_AES_GCM_192_KEY_LEN_WSALT                                         \
+    (SRTP_AEAD_SALT_LEN + SRTP_AES_192_KEY_LEN)
+#define SRTP_AES_GCM_256_KEY_LEN_WSALT                                         \
+    (SRTP_AEAD_SALT_LEN + SRTP_AES_256_KEY_LEN)
+
+/**
+ *  @brief A srtp_cipher_type_id_t is an identifier for a particular cipher
+ *  type.
+ *
+ *  A srtp_cipher_type_id_t is an integer that represents a particular
+ *  cipher type, e.g. the Advanced Encryption Standard (AES).  A
+ *  SRTP_NULL_CIPHER is avaliable; this cipher leaves the data unchanged,
+ *  and can be selected to indicate that no encryption is to take
+ *  place.
+ *
+ *  @ingroup Ciphers
+ */
+typedef uint32_t srtp_cipher_type_id_t;
+
+/**
+ *  @brief An srtp_auth_type_id_t is an identifier for a particular
+ * authentication
+ *   function.
+ *
+ *  An srtp_auth_type_id_t is an integer that represents a particular
+ *  authentication function type, e.g. HMAC-SHA1.  A SRTP_NULL_AUTH is
+ *  avaliable; this authentication function performs no computation,
+ *  and can be selected to indicate that no authentication is to take
+ *  place.
+ *
+ *  @ingroup Authentication
+ */
+typedef uint32_t srtp_auth_type_id_t;
+
+/**
+ * @brief srtp_err_status_t defines error codes.
+ *
+ * The enumeration srtp_err_status_t defines error codes.  Note that the
+ * value of srtp_err_status_ok is equal to zero, which can simplify error
+ * checking somewhat.
+ *
+ */
+typedef enum {
+    srtp_err_status_ok = 0,             /**< nothing to report               */
+    srtp_err_status_fail = 1,           /**< unspecified failure             */
+    srtp_err_status_bad_param = 2,      /**< unsupported parameter           */
+    srtp_err_status_alloc_fail = 3,     /**< couldn't allocate memory        */
+    srtp_err_status_dealloc_fail = 4,   /**< couldn't deallocate properly    */
+    srtp_err_status_init_fail = 5,      /**< couldn't initialize             */
+    srtp_err_status_terminus = 6,       /**< can't process as much data as   */
+                                        /**< requested                       */
+    srtp_err_status_auth_fail = 7,      /**< authentication failure          */
+    srtp_err_status_cipher_fail = 8,    /**< cipher failure                  */
+    srtp_err_status_replay_fail = 9,    /**< replay check failed (bad index) */
+    srtp_err_status_replay_old = 10,    /**< replay check failed (index too  */
+                                        /**< old)                            */
+    srtp_err_status_algo_fail = 11,     /**< algorithm failed test routine   */
+    srtp_err_status_no_such_op = 12,    /**< unsupported operation           */
+    srtp_err_status_no_ctx = 13,        /**< no appropriate context found    */
+    srtp_err_status_cant_check = 14,    /**< unable to perform desired       */
+                                        /**< validation                      */
+    srtp_err_status_key_expired = 15,   /**< can't use key any more          */
+    srtp_err_status_socket_err = 16,    /**< error in use of socket          */
+    srtp_err_status_signal_err = 17,    /**< error in use POSIX signals      */
+    srtp_err_status_nonce_bad = 18,     /**< nonce check failed              */
+    srtp_err_status_read_fail = 19,     /**< couldn't read data              */
+    srtp_err_status_write_fail = 20,    /**< couldn't write data             */
+    srtp_err_status_parse_err = 21,     /**< error parsing data              */
+    srtp_err_status_encode_err = 22,    /**< error encoding data             */
+    srtp_err_status_semaphore_err = 23, /**< error while using semaphores    */
+    srtp_err_status_pfkey_err = 24,     /**< error while using pfkey         */
+    srtp_err_status_bad_mki = 25,       /**< error MKI present in packet is  */
+                                        /**< invalid                         */
+    srtp_err_status_pkt_idx_old = 26,   /**< packet index is too old to      */
+                                        /**< consider                        */
+    srtp_err_status_pkt_idx_adv = 27    /**< packet index advanced, reset    */
+                                        /**< needed                          */
+} srtp_err_status_t;
+
+typedef struct srtp_ctx_t_ srtp_ctx_t;
+
+/**
+ * @brief srtp_sec_serv_t describes a set of security services.
+ *
+ * A srtp_sec_serv_t enumeration is used to describe the particular
+ * security services that will be applied by a particular crypto
+ * policy (or other mechanism).
+ */
+typedef enum {
+    sec_serv_none = 0,         /**< no services                        */
+    sec_serv_conf = 1,         /**< confidentiality                    */
+    sec_serv_auth = 2,         /**< authentication                     */
+    sec_serv_conf_and_auth = 3 /**< confidentiality and authentication */
+} srtp_sec_serv_t;
+
+/**
+ * @brief srtp_crypto_policy_t describes a particular crypto policy that
+ * can be applied to an SRTP stream.
+ *
+ * A srtp_crypto_policy_t describes a particular cryptographic policy that
+ * can be applied to an SRTP or SRTCP stream.  An SRTP session policy
+ * consists of a list of these policies, one for each SRTP stream
+ * in the session.
+ */
+typedef struct srtp_crypto_policy_t {
+    srtp_cipher_type_id_t cipher_type; /**< An integer representing          */
+                                       /**< the type of cipher.              */
+    int cipher_key_len;                /**< The length of the cipher key     */
+                                       /**< in octets.                       */
+    srtp_auth_type_id_t auth_type;     /**< An integer representing the      */
+                                       /**< authentication function.         */
+    int auth_key_len;                  /**< The length of the authentication */
+                                       /**< function key in octets.          */
+    int auth_tag_len;                  /**< The length of the authentication */
+                                       /**< tag in octets.                   */
+    srtp_sec_serv_t sec_serv;          /**< The flag indicating the security */
+                                       /**< services to be applied.          */
+} srtp_crypto_policy_t;
+
+/**
+ * @brief srtp_ssrc_type_t describes the type of an SSRC.
+ *
+ * An srtp_ssrc_type_t enumeration is used to indicate a type of SSRC.  See
+ * @ref srtp_policy_t for more informataion.
+ */
+typedef enum {
+    ssrc_undefined = 0,   /**< Indicates an undefined SSRC type.    */
+    ssrc_specific = 1,    /**< Indicates a specific SSRC value      */
+    ssrc_any_inbound = 2, /**< Indicates any inbound SSRC value     */
+                          /**< (i.e. a value that is used in the    */
+                          /**< function srtp_unprotect())           */
+    ssrc_any_outbound = 3 /**< Indicates any outbound SSRC value    */
+                          /**< (i.e. a value that is used in the    */
+                          /**< function srtp_protect())             */
+} srtp_ssrc_type_t;
+
+/**
+ * @brief An srtp_ssrc_t represents a particular SSRC value, or a `wildcard'
+ * SSRC.
+ *
+ * An srtp_ssrc_t represents a particular SSRC value (if its type is
+ * ssrc_specific), or a wildcard SSRC value that will match all
+ * outbound SSRCs (if its type is ssrc_any_outbound) or all inbound
+ * SSRCs (if its type is ssrc_any_inbound).
+ */
+typedef struct {
+    srtp_ssrc_type_t type; /**< The type of this particular SSRC */
+    unsigned int value;    /**< The value of this SSRC, if it is not a */
+                           /**< wildcard */
+} srtp_ssrc_t;
+
+/**
+ * @brief points to an EKT policy
+ */
+typedef struct srtp_ekt_policy_ctx_t *srtp_ekt_policy_t;
+
+/**
+ * @brief points to EKT stream data
+ */
+typedef struct srtp_ekt_stream_ctx_t *srtp_ekt_stream_t;
+
+/**
+ * @brief srtp_master_key_t represents a master key.  There will
+ * be a Master Key Index and the Master Key associated with the
+ * Master Key Index.  Need to also keep track of the Master Key
+ * Index Size to correctly read it from a packet.
+ */
+typedef struct srtp_master_key_t {
+    unsigned char *key;
+    unsigned char *mki_id;
+    unsigned int mki_size;
+} srtp_master_key_t;
+
+/**
+ * @brief represents the policy for an SRTP session.
+ *
+ * A single srtp_policy_t struct represents the policy for a single
+ * SRTP stream, and a linked list of these elements represents the
+ * policy for an entire SRTP session.  Each element contains the SRTP
+ * and SRTCP crypto policies for that stream, a pointer to the SRTP
+ * master key for that stream, the SSRC describing that stream, or a
+ * flag indicating a `wildcard' SSRC value, and a `next' field that
+ * holds a pointer to the next element in the list of policy elements,
+ * or NULL if it is the last element.
+ *
+ * The wildcard value SSRC_ANY_INBOUND matches any SSRC from an
+ * inbound stream that for which there is no explicit SSRC entry in
+ * another policy element.  Similarly, the value SSRC_ANY_OUTBOUND
+ * will matches any SSRC from an outbound stream that does not appear
+ * in another policy element.  Note that wildcard SSRCs &b cannot be
+ * used to match both inbound and outbound traffic.  This restriction
+ * is intentional, and it allows libSRTP to ensure that no security
+ * lapses result from accidental re-use of SSRC values during key
+ * sharing.
+ *
+ * @warning The final element of the list @b must have its `next' pointer
+ *          set to NULL.
+ */
+
+typedef struct srtp_policy_t {
+    srtp_ssrc_t ssrc;              /**< The SSRC value of stream, or the    */
+                                   /**< flags SSRC_ANY_INBOUND or           */
+                                   /**< SSRC_ANY_OUTBOUND if key sharing    */
+                                   /**< is used for this policy element.    */
+    srtp_crypto_policy_t rtp;      /**< SRTP crypto policy.                 */
+    srtp_crypto_policy_t rtcp;     /**< SRTCP crypto policy.                */
+    unsigned char *key;            /**< Pointer to the SRTP master key for  */
+                                   /**< this stream.                        */
+    srtp_master_key_t **keys;      /** Array of Master Key structures       */
+    unsigned long num_master_keys; /** Number of master keys                */
+    srtp_ekt_policy_t ekt;         /**< Pointer to the EKT policy structure */
+                                   /**< for this stream (if any)            */
+    unsigned long window_size;     /**< The window size to use for replay   */
+                                   /**< protection.                         */
+    int allow_repeat_tx;           /**< Whether retransmissions of          */
+                                   /**< packets with the same sequence      */
+                                   /**< number are allowed.                 */
+                                   /**< (Note that such repeated            */
+                                   /**< transmissions must have the same    */
+                                   /**< RTP payload, or a severe security   */
+                                   /**< weakness is introduced!)            */
+    int *enc_xtn_hdr;              /**< List of header ids to encrypt.      */
+    int enc_xtn_hdr_count;         /**< Number of entries in list of header */
+                                   /**<  ids.                               */
+    struct srtp_policy_t *next;    /**< Pointer to next stream policy.      */
+} srtp_policy_t;
+
+/**
+ * @brief An srtp_t points to an SRTP session structure.
+ *
+ * The typedef srtp_t is a pointer to a structure that represents
+ * an SRTP session.  This datatype is intentially opaque in
+ * order to separate the interface from the implementation.
+ *
+ * An SRTP session consists of all of the traffic sent to the RTP and
+ * RTCP destination transport addresses, using the RTP/SAVP (Secure
+ * Audio/Video Profile).  A session can be viewed as a set of SRTP
+ * streams, each of which originates with a different participant.
+ */
+typedef srtp_ctx_t *srtp_t;
+
+/**
+ * @brief srtp_init() initializes the srtp library.
+ *
+ * @warning This function @b must be called before any other srtp
+ * functions.
+ */
+srtp_err_status_t srtp_init(void);
+
+/**
+ * @brief srtp_shutdown() de-initializes the srtp library.
+ *
+ * @warning No srtp functions may be called after calling this function.
+ */
+srtp_err_status_t srtp_shutdown(void);
+
+/**
+ * @brief srtp_protect() is the Secure RTP sender-side packet processing
+ * function.
+ *
+ * The function call srtp_protect(ctx, rtp_hdr, len_ptr) applies SRTP
+ * protection to the RTP packet rtp_hdr (which has length *len_ptr) using
+ * the SRTP context ctx.  If srtp_err_status_ok is returned, then rtp_hdr
+ * points to the resulting SRTP packet and *len_ptr is the number of
+ * octets in that packet; otherwise, no assumptions should be made
+ * about the value of either data elements.
+ *
+ * The sequence numbers of the RTP packets presented to this function
+ * need not be consecutive, but they @b must be out of order by less
+ * than 2^15 = 32,768 packets.
+ *
+ * @warning This function assumes that it can write the authentication
+ * tag into the location in memory immediately following the RTP
+ * packet, and assumes that the RTP packet is aligned on a 32-bit
+ * boundary.
+ *
+ * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN
+ * into the location in memory immediately following the RTP packet.
+ * Callers MUST ensure that this much writable memory is available in
+ * the buffer that holds the RTP packet.
+ *
+ * @param ctx is the SRTP context to use in processing the packet.
+ *
+ * @param rtp_hdr is a pointer to the RTP packet (before the call); after
+ * the function returns, it points to the srtp packet.
+ *
+ * @param len_ptr is a pointer to the length in octets of the complete
+ * RTP packet (header and body) before the function call, and of the
+ * complete SRTP packet after the call, if srtp_err_status_ok was returned.
+ * Otherwise, the value of the data to which it points is undefined.
+ *
+ * @return
+ *    - srtp_err_status_ok            no problems
+ *    - srtp_err_status_replay_fail   rtp sequence number was non-increasing
+ *    - @e other                 failure in cryptographic mechanisms
+ */
+srtp_err_status_t srtp_protect(srtp_t ctx, void *rtp_hdr, int *len_ptr);
+
+/**
+ * @brief srtp_protect_mki() is the Secure RTP sender-side packet processing
+ * function that can utilize MKI.
+ *
+ * The function call srtp_protect(ctx, rtp_hdr, len_ptr) applies SRTP
+ * protection to the RTP packet rtp_hdr (which has length *len_ptr) using
+ * the SRTP context ctx.  If srtp_err_status_ok is returned, then rtp_hdr
+ * points to the resulting SRTP packet and *len_ptr is the number of
+ * octets in that packet; otherwise, no assumptions should be made
+ * about the value of either data elements.
+ *
+ * The sequence numbers of the RTP packets presented to this function
+ * need not be consecutive, but they @b must be out of order by less
+ * than 2^15 = 32,768 packets.
+ *
+ * @warning This function assumes that it can write the authentication
+ * tag into the location in memory immediately following the RTP
+ * packet, and assumes that the RTP packet is aligned on a 32-bit
+ * boundary.
+ *
+ * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN
+ * into the location in memory immediately following the RTP packet.
+ * Callers MUST ensure that this much writable memory is available in
+ * the buffer that holds the RTP packet.
+ *
+ * @param ctx is the SRTP context to use in processing the packet.
+ *
+ * @param rtp_hdr is a pointer to the RTP packet (before the call); after
+ * the function returns, it points to the srtp packet.
+ *
+ * @param pkt_octet_len is a pointer to the length in octets of the complete
+ * RTP packet (header and body) before the function call, and of the
+ * complete SRTP packet after the call, if srtp_err_status_ok was returned.
+ * Otherwise, the value of the data to which it points is undefined.
+ *
+ * @param use_mki is a boolean to tell the system if mki is being used.  If
+ * set to false then will use the first set of session keys.  If set to true
+ * will
+ * use the session keys identified by the mki_index
+ *
+ * @param mki_index integer value specifying which set of session keys should be
+ * used if use_mki is set to true.
+ *
+ * @return
+ *    - srtp_err_status_ok            no problems
+ *    - srtp_err_status_replay_fail   rtp sequence number was non-increasing
+ *    - @e other                 failure in cryptographic mechanisms
+ */
+srtp_err_status_t srtp_protect_mki(srtp_ctx_t *ctx,
+                                   void *rtp_hdr,
+                                   int *pkt_octet_len,
+                                   unsigned int use_mki,
+                                   unsigned int mki_index);
+
+/**
+ * @brief srtp_unprotect() is the Secure RTP receiver-side packet
+ * processing function.
+ *
+ * The function call srtp_unprotect(ctx, srtp_hdr, len_ptr) verifies
+ * the Secure RTP protection of the SRTP packet pointed to by srtp_hdr
+ * (which has length *len_ptr), using the SRTP context ctx.  If
+ * srtp_err_status_ok is returned, then srtp_hdr points to the resulting
+ * RTP packet and *len_ptr is the number of octets in that packet;
+ * otherwise, no assumptions should be made about the value of either
+ * data elements.
+ *
+ * The sequence numbers of the RTP packets presented to this function
+ * need not be consecutive, but they @b must be out of order by less
+ * than 2^15 = 32,768 packets.
+ *
+ * @warning This function assumes that the SRTP packet is aligned on a
+ * 32-bit boundary.
+ *
+ * @param ctx is the SRTP session which applies to the particular packet.
+ *
+ * @param srtp_hdr is a pointer to the header of the SRTP packet
+ * (before the call).  after the function returns, it points to the
+ * rtp packet if srtp_err_status_ok was returned; otherwise, the value of
+ * the data to which it points is undefined.
+ *
+ * @param len_ptr is a pointer to the length in octets of the complete
+ * srtp packet (header and body) before the function call, and of the
+ * complete rtp packet after the call, if srtp_err_status_ok was returned.
+ * Otherwise, the value of the data to which it points is undefined.
+ *
+ * @return
+ *    - srtp_err_status_ok          if the RTP packet is valid.
+ *    - srtp_err_status_auth_fail   if the SRTP packet failed the message
+ *                                  authentication check.
+ *    - srtp_err_status_replay_fail if the SRTP packet is a replay (e.g. packet
+ *                                  has already been processed and accepted).
+ *    - [other]  if there has been an error in the cryptographic mechanisms.
+ *
+ */
+srtp_err_status_t srtp_unprotect(srtp_t ctx, void *srtp_hdr, int *len_ptr);
+
+/**
+ * @brief srtp_unprotect_mki() is the Secure RTP receiver-side packet
+ * processing function that checks for MKI.
+ *
+ * The function call srtp_unprotect(ctx, srtp_hdr, len_ptr) verifies
+ * the Secure RTP protection of the SRTP packet pointed to by srtp_hdr
+ * (which has length *len_ptr), using the SRTP context ctx.  If
+ * srtp_err_status_ok is returned, then srtp_hdr points to the resulting
+ * RTP packet and *len_ptr is the number of octets in that packet;
+ * otherwise, no assumptions should be made about the value of either
+ * data elements.
+ *
+ * The sequence numbers of the RTP packets presented to this function
+ * need not be consecutive, but they @b must be out of order by less
+ * than 2^15 = 32,768 packets.
+ *
+ * @warning This function assumes that the SRTP packet is aligned on a
+ * 32-bit boundary.
+ *
+ * @param ctx is the SRTP session which applies to the particular packet.
+ *
+ * @param srtp_hdr is a pointer to the header of the SRTP packet
+ * (before the call).  after the function returns, it points to the
+ * rtp packet if srtp_err_status_ok was returned; otherwise, the value of
+ * the data to which it points is undefined.
+ *
+ * @param len_ptr is a pointer to the length in octets of the complete
+ * srtp packet (header and body) before the function call, and of the
+ * complete rtp packet after the call, if srtp_err_status_ok was returned.
+ * Otherwise, the value of the data to which it points is undefined.
+ *
+ * @param use_mki is a boolean to tell the system if mki is being used.  If
+ * set to false then will use the first set of session keys.  If set to true
+ * will
+ * use the session keys identified by the mki_index
+ *
+ * @return
+ *    - srtp_err_status_ok          if the RTP packet is valid.
+ *    - srtp_err_status_auth_fail   if the SRTP packet failed the message
+ *                                  authentication check.
+ *    - srtp_err_status_replay_fail if the SRTP packet is a replay (e.g. packet
+ *                                  has already been processed and accepted).
+ *    - srtp_err_status_bad_mki if the MKI in the packet is not a known MKI id
+ *    - [other]  if there has been an error in the cryptographic mechanisms.
+ *
+ */
+srtp_err_status_t srtp_unprotect_mki(srtp_t ctx,
+                                     void *srtp_hdr,
+                                     int *len_ptr,
+                                     unsigned int use_mki);
+
+/**
+ * @brief srtp_create() allocates and initializes an SRTP session.
+
+ * The function call srtp_create(session, policy) allocates and
+ * initializes an SRTP session context, applying the given policy.
+ *
+ * @param session is a pointer to the SRTP session to which the policy is
+ * to be added.
+ *
+ * @param policy is the srtp_policy_t struct that describes the policy
+ * for the session.  The struct may be a single element, or it may be
+ * the head of a list, in which case each element of the list is
+ * processed.  It may also be NULL, in which case streams should be added
+ * later using srtp_add_stream().  The final element of the list @b must
+ * have its `next' field set to NULL.
+ *
+ * @return
+ *    - srtp_err_status_ok           if creation succeded.
+ *    - srtp_err_status_alloc_fail   if allocation failed.
+ *    - srtp_err_status_init_fail    if initialization failed.
+ */
+srtp_err_status_t srtp_create(srtp_t *session, const srtp_policy_t *policy);
+
+/**
+ * @brief srtp_add_stream() allocates and initializes an SRTP stream
+ * within a given SRTP session.
+ *
+ * The function call srtp_add_stream(session, policy) allocates and
+ * initializes a new SRTP stream within a given, previously created
+ * session, applying the policy given as the other argument to that
+ * stream.
+ *
+ * @return values:
+ *    - srtp_err_status_ok           if stream creation succeded.
+ *    - srtp_err_status_alloc_fail   if stream allocation failed
+ *    - srtp_err_status_init_fail    if stream initialization failed.
+ */
+srtp_err_status_t srtp_add_stream(srtp_t session, const srtp_policy_t *policy);
+
+/**
+ * @brief srtp_remove_stream() deallocates an SRTP stream.
+ *
+ * The function call srtp_remove_stream(session, ssrc) removes
+ * the SRTP stream with the SSRC value ssrc from the SRTP session
+ * context given by the argument session.
+ *
+ * @param session is the SRTP session from which the stream
+ *        will be removed.
+ *
+ * @param ssrc is the SSRC value of the stream to be removed
+ *             in network byte order.
+ *
+ * @warning Wildcard SSRC values cannot be removed from a
+ *          session.
+ *
+ * @return
+ *    - srtp_err_status_ok     if the stream deallocation succeded.
+ *    - [other]           otherwise.
+ *
+ */
+srtp_err_status_t srtp_remove_stream(srtp_t session, unsigned int ssrc);
+
+/**
+ * @brief srtp_update() udpates all streams in the session.
+ *
+ * The function call srtp_update(session, policy) updates
+ * all the streams in the session applying the given policy
+ * and key. The exsisting ROC value of all streams will be
+ * preserved.
+ *
+ * @param session is the SRTP session that contains the streams
+ *        to be updated.
+ *
+ * @param policy is the srtp_policy_t struct that describes the policy
+ * for the session.  The struct may be a single element, or it may be
+ * the head of a list, in which case each element of the list is
+ * processed. The final element of the list @b must
+ * have its `next' field set to NULL.
+ *
+ * @return
+ *    - srtp_err_status_ok           if stream creation succeded.
+ *    - srtp_err_status_alloc_fail   if stream allocation failed
+ *    - srtp_err_status_init_fail    if stream initialization failed.
+ *    - [other]                 otherwise.
+ *
+ */
+srtp_err_status_t srtp_update(srtp_t session, const srtp_policy_t *policy);
+
+/**
+ * @brief srtp_update_stream() udpates a SRTP stream.
+ *
+ * The function call srtp_update_stream(session, policy) updates
+ * the stream(s) in the session that match applying the given
+ * policy and key. The exsisting ROC value of all stream(s) will
+ * be preserved.
+ *
+ * @param session is the SRTP session that contains the streams
+ *        to be updated.
+ *
+ * @param policy is the srtp_policy_t struct that describes the policy
+ * for the session.
+ *
+ * @return
+ *    - srtp_err_status_ok           if stream creation succeded.
+ *    - srtp_err_status_alloc_fail   if stream allocation failed
+ *    - srtp_err_status_init_fail    if stream initialization failed.
+ *    - [other]                      otherwise.
+ *
+ */
+srtp_err_status_t srtp_update_stream(srtp_t session,
+                                     const srtp_policy_t *policy);
+
+/**
+ * @brief srtp_crypto_policy_set_rtp_default() sets a crypto policy
+ * structure to the SRTP default policy for RTP protection.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call crypto_policy_set_rtp_default(&p) sets the
+ * crypto_policy_t at location p to the SRTP default policy for RTP
+ * protection, as defined in the specification.  This function is a
+ * convenience that helps to avoid dealing directly with the policy
+ * data structure.  You are encouraged to initialize policy elements
+ * with this function call.  Doing so may allow your code to be
+ * forward compatible with later versions of libSRTP that include more
+ * elements in the crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_rtp_default(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_rtcp_default() sets a crypto policy
+ * structure to the SRTP default policy for RTCP protection.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_rtcp_default(&p) sets the
+ * srtp_crypto_policy_t at location p to the SRTP default policy for RTCP
+ * protection, as defined in the specification.  This function is a
+ * convenience that helps to avoid dealing directly with the policy
+ * data structure.  You are encouraged to initialize policy elements
+ * with this function call.  Doing so may allow your code to be
+ * forward compatible with later versions of libSRTP that include more
+ * elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_rtcp_default(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80() sets a crypto
+ * policy structure to the SRTP default policy for RTP protection.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80() is a
+ * synonym for srtp_crypto_policy_set_rtp_default().  It conforms to the
+ * naming convention used in RFC 4568 (SDP Security Descriptions for
+ * Media Streams).
+ *
+ * @return void.
+ *
+ */
+#define srtp_crypto_policy_set_aes_cm_128_hmac_sha1_80(p)                      \
+    srtp_crypto_policy_set_rtp_default(p)
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32() sets a crypto
+ * policy structure to a short-authentication tag policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32(&p)
+ * sets the srtp_crypto_policy_t at location p to use policy
+ * AES_CM_128_HMAC_SHA1_32 as defined in RFC 4568.
+ * This policy uses AES-128
+ * Counter Mode encryption and HMAC-SHA1 authentication, with an
+ * authentication tag that is only 32 bits long.  This length is
+ * considered adequate only for protecting audio and video media that
+ * use a stateless playback function.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This crypto policy is intended for use in SRTP, but not in
+ * SRTCP.  It is recommended that a policy that uses longer
+ * authentication tags be used for SRTCP.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_128_hmac_sha1_32(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_128_null_auth() sets a crypto
+ * policy structure to an encryption-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_128_null_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-128 Counter Mode), but to use no authentication method.  This
+ * policy is NOT RECOMMENDED unless it is unavoidable; see Section 7.5
+ * of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This policy is NOT RECOMMENDED for SRTP unless it is
+ * unavoidable, and it is NOT RECOMMENDED at all for SRTCP; see
+ * Section 7.5 of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_128_null_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_null_cipher_hmac_sha1_80() sets a crypto
+ * policy structure to an authentication-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_null_cipher_hmac_sha1_80(&p)
+ * sets the srtp_crypto_policy_t at location p to use HMAC-SHA1 with an 80
+ * bit authentication tag to provide message authentication, but to
+ * use no encryption.  This policy is NOT RECOMMENDED for SRTP unless
+ * there is a requirement to forego encryption.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This policy is NOT RECOMMENDED for SRTP unless there is a
+ * requirement to forego encryption.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_null_cipher_hmac_sha1_80(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_null_cipher_hmac_null() sets a crypto
+ * policy structure to use no encryption or authentication.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_null_cipher_hmac_null(&p)
+ * sets the srtp_crypto_policy_t at location p to use no encryption and
+ * no authentication.  This policy should only be used for testing and
+ * troubleshootingl.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This policy is NOT RECOMMENDED for SRTP unless there is a
+ * requirement to forego encryption and authentication.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_null_cipher_hmac_null(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80() sets a crypto
+ * policy structure to a encryption and authentication policy using AES-256
+ * for RTP protection.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80(&p)
+ * sets the srtp_crypto_policy_t at location p to use policy
+ * AES_CM_256_HMAC_SHA1_80 as defined in RFC 6188.  This policy uses AES-256
+ * Counter Mode encryption and HMAC-SHA1 authentication, with an 80 bit
+ * authentication tag.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_256_hmac_sha1_80(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32() sets a crypto
+ * policy structure to a short-authentication tag policy using AES-256
+ * encryption.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32(&p)
+ * sets the srtp_crypto_policy_t at location p to use policy
+ * AES_CM_256_HMAC_SHA1_32 as defined in RFC 6188.  This policy uses AES-256
+ * Counter Mode encryption and HMAC-SHA1 authentication, with an
+ * authentication tag that is only 32 bits long.  This length is
+ * considered adequate only for protecting audio and video media that
+ * use a stateless playback function.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This crypto policy is intended for use in SRTP, but not in
+ * SRTCP.  It is recommended that a policy that uses longer
+ * authentication tags be used for SRTCP.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_256_hmac_sha1_32(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_256_null_auth() sets a crypto
+ * policy structure to an encryption-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_256_null_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-256 Counter Mode), but to use no authentication method.  This
+ * policy is NOT RECOMMENDED unless it is unavoidable; see Section 7.5
+ * of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @warning This policy is NOT RECOMMENDED for SRTP unless it is
+ * unavoidable, and it is NOT RECOMMENDED at all for SRTCP; see
+ * Section 7.5 of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_256_null_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80() sets a crypto
+ * policy structure to a encryption and authentication policy using AES-192
+ * for RTP protection.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80(&p)
+ * sets the crypto_policy_t at location p to use policy
+ * AES_CM_192_HMAC_SHA1_80 as defined in RFC 6188.  This policy uses AES-192
+ * Counter Mode encryption and HMAC-SHA1 authentication, with an 80 bit
+ * authentication tag.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_192_hmac_sha1_80(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32() sets a crypto
+ * policy structure to a short-authentication tag policy using AES-192
+ * encryption.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32(&p)
+ * sets the crypto_policy_t at location p to use policy
+ * AES_CM_192_HMAC_SHA1_32 as defined in RFC 6188.  This policy uses AES-192
+ * Counter Mode encryption and HMAC-SHA1 authentication, with an
+ * authentication tag that is only 32 bits long.  This length is
+ * considered adequate only for protecting audio and video media that
+ * use a stateless playback function.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the crypto_policy_t datatype.
+ *
+ * @warning This crypto policy is intended for use in SRTP, but not in
+ * SRTCP.  It is recommended that a policy that uses longer
+ * authentication tags be used for SRTCP.  See Section 7.5 of RFC 3711
+ * (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_192_hmac_sha1_32(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_cm_192_null_auth() sets a crypto
+ * policy structure to an encryption-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_cm_192_null_auth(&p) sets
+ * the crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-192 Counter Mode), but to use no authentication method.  This
+ * policy is NOT RECOMMENDED unless it is unavoidable; see Section 7.5
+ * of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the crypto_policy_t datatype.
+ *
+ * @warning This policy is NOT RECOMMENDED for SRTP unless it is
+ * unavoidable, and it is NOT RECOMMENDED at all for SRTCP; see
+ * Section 7.5 of RFC 3711 (http://www.ietf.org/rfc/rfc3711.txt).
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_cm_192_null_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_128_8_auth() sets a crypto
+ * policy structure to an AEAD encryption policy.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_128_8_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-128 Galois Counter Mode) with 8 octet auth tag.  This
+ * policy applies confidentiality and authentication to both the
+ * RTP and RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_128_8_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_256_8_auth() sets a crypto
+ * policy structure to an AEAD encryption policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_256_8_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-256 Galois Counter Mode) with 8 octet auth tag.  This
+ * policy applies confidentiality and authentication to both the
+ * RTP and RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_256_8_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_128_8_only_auth() sets a crypto
+ * policy structure to an AEAD authentication-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_128_8_only_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-128 Galois Counter Mode) with 8 octet auth tag.  This policy
+ * applies confidentiality and authentication to the RTP packets,
+ * but only authentication to the RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_128_8_only_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_256_8_only_auth() sets a crypto
+ * policy structure to an AEAD authentication-only policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_256_8_only_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-256 Galois Counter Mode) with 8 octet auth tag.  This policy
+ * applies confidentiality and authentication to the RTP packets,
+ * but only authentication to the RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_256_8_only_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_128_16_auth() sets a crypto
+ * policy structure to an AEAD encryption policy.
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_128_16_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-128 Galois Counter Mode) with 16 octet auth tag.  This
+ * policy applies confidentiality and authentication to both the
+ * RTP and RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_128_16_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_crypto_policy_set_aes_gcm_256_16_auth() sets a crypto
+ * policy structure to an AEAD encryption policy
+ *
+ * @param p is a pointer to the policy structure to be set
+ *
+ * The function call srtp_crypto_policy_set_aes_gcm_256_16_auth(&p) sets
+ * the srtp_crypto_policy_t at location p to use the SRTP default cipher
+ * (AES-256 Galois Counter Mode) with 16 octet auth tag.  This
+ * policy applies confidentiality and authentication to both the
+ * RTP and RTCP packets.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return void.
+ *
+ */
+void srtp_crypto_policy_set_aes_gcm_256_16_auth(srtp_crypto_policy_t *p);
+
+/**
+ * @brief srtp_dealloc() deallocates storage for an SRTP session
+ * context.
+ *
+ * The function call srtp_dealloc(s) deallocates storage for the
+ * SRTP session context s.  This function should be called no more
+ * than one time for each of the contexts allocated by the function
+ * srtp_create().
+ *
+ * @param s is the srtp_t for the session to be deallocated.
+ *
+ * @return
+ *    - srtp_err_status_ok             if there no problems.
+ *    - srtp_err_status_dealloc_fail   a memory deallocation failure occured.
+ */
+srtp_err_status_t srtp_dealloc(srtp_t s);
+
+/*
+ * @brief identifies a particular SRTP profile
+ *
+ * An srtp_profile_t enumeration is used to identify a particular SRTP
+ * profile (that is, a set of algorithms and parameters). These profiles
+ * are defined for DTLS-SRTP:
+ * https://www.iana.org/assignments/srtp-protection/srtp-protection.xhtml
+ */
+typedef enum {
+    srtp_profile_reserved = 0,
+    srtp_profile_aes128_cm_sha1_80 = 1,
+    srtp_profile_aes128_cm_sha1_32 = 2,
+    srtp_profile_null_sha1_80 = 5,
+    srtp_profile_null_sha1_32 = 6,
+    srtp_profile_aead_aes_128_gcm = 7,
+    srtp_profile_aead_aes_256_gcm = 8,
+} srtp_profile_t;
+
+/**
+ * @brief srtp_crypto_policy_set_from_profile_for_rtp() sets a crypto policy
+ * structure to the appropriate value for RTP based on an srtp_profile_t
+ *
+ * @param policy is a pointer to the policy structure to be set
+ *
+ * @param profile is an enumeration for the policy to be set
+ *
+ * The function call srtp_crypto_policy_set_rtp_default(&policy, profile)
+ * sets the srtp_crypto_policy_t at location policy to the policy for RTP
+ * protection, as defined by the srtp_profile_t profile.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return values
+ *     - srtp_err_status_ok         no problems were encountered
+ *     - srtp_err_status_bad_param  the profile is not supported
+ *
+ */
+srtp_err_status_t srtp_crypto_policy_set_from_profile_for_rtp(
+    srtp_crypto_policy_t *policy,
+    srtp_profile_t profile);
+
+/**
+ * @brief srtp_crypto_policy_set_from_profile_for_rtcp() sets a crypto policy
+ * structure to the appropriate value for RTCP based on an srtp_profile_t
+ *
+ * @param policy is a pointer to the policy structure to be set
+ *
+ * @param profile is an enumeration for the policy to be set
+ *
+ * The function call srtp_crypto_policy_set_rtcp_default(&policy, profile)
+ * sets the srtp_crypto_policy_t at location policy to the policy for RTCP
+ * protection, as defined by the srtp_profile_t profile.
+ *
+ * This function is a convenience that helps to avoid dealing directly
+ * with the policy data structure.  You are encouraged to initialize
+ * policy elements with this function call.  Doing so may allow your
+ * code to be forward compatible with later versions of libSRTP that
+ * include more elements in the srtp_crypto_policy_t datatype.
+ *
+ * @return values
+ *     - srtp_err_status_ok         no problems were encountered
+ *     - srtp_err_status_bad_param  the profile is not supported
+ *
+ */
+srtp_err_status_t srtp_crypto_policy_set_from_profile_for_rtcp(
+    srtp_crypto_policy_t *policy,
+    srtp_profile_t profile);
+
+/**
+ * @brief returns the master key length for a given SRTP profile
+ */
+unsigned int srtp_profile_get_master_key_length(srtp_profile_t profile);
+
+/**
+ * @brief returns the master salt length for a given SRTP profile
+ */
+unsigned int srtp_profile_get_master_salt_length(srtp_profile_t profile);
+
+/**
+ * @brief appends the salt to the key
+ *
+ * The function call srtp_append_salt_to_key(k, klen, s, slen)
+ * copies the string s to the location at klen bytes following
+ * the location k.
+ *
+ * @warning There must be at least bytes_in_salt + bytes_in_key bytes
+ *          available at the location pointed to by key.
+ *
+ */
+void srtp_append_salt_to_key(unsigned char *key,
+                             unsigned int bytes_in_key,
+                             unsigned char *salt,
+                             unsigned int bytes_in_salt);
+
+/**
+ * @}
+ */
+
+/**
+ * @defgroup SRTCP Secure RTCP
+ * @ingroup  SRTP
+ *
+ * @brief Secure RTCP functions are used to protect RTCP traffic.
+ *
+ * RTCP is the control protocol for RTP.  libSRTP protects RTCP
+ * traffic in much the same way as it does RTP traffic.  The function
+ * srtp_protect_rtcp() applies cryptographic protections to outbound
+ * RTCP packets, and srtp_unprotect_rtcp() verifies the protections on
+ * inbound RTCP packets.
+ *
+ * A note on the naming convention: srtp_protect_rtcp() has an srtp_t
+ * as its first argument, and thus has `srtp_' as its prefix.  The
+ * trailing `_rtcp' indicates the protocol on which it acts.
+ *
+ * @{
+ */
+
+/**
+ * @brief srtp_protect_rtcp() is the Secure RTCP sender-side packet
+ * processing function.
+ *
+ * The function call srtp_protect_rtcp(ctx, rtp_hdr, len_ptr) applies
+ * SRTCP protection to the RTCP packet rtcp_hdr (which has length
+ * *len_ptr) using the SRTP session context ctx.  If srtp_err_status_ok is
+ * returned, then rtp_hdr points to the resulting SRTCP packet and
+ * *len_ptr is the number of octets in that packet; otherwise, no
+ * assumptions should be made about the value of either data elements.
+ *
+ * @warning This function assumes that it can write the authentication
+ * tag into the location in memory immediately following the RTCP
+ * packet, and assumes that the RTCP packet is aligned on a 32-bit
+ * boundary.
+ *
+ * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN+4
+ * into the location in memory immediately following the RTCP packet.
+ * Callers MUST ensure that this much writable memory is available in
+ * the buffer that holds the RTCP packet.
+ *
+ * @param ctx is the SRTP context to use in processing the packet.
+ *
+ * @param rtcp_hdr is a pointer to the RTCP packet (before the call); after
+ * the function returns, it points to the srtp packet.
+ *
+ * @param pkt_octet_len is a pointer to the length in octets of the
+ * complete RTCP packet (header and body) before the function call,
+ * and of the complete SRTCP packet after the call, if srtp_err_status_ok
+ * was returned.  Otherwise, the value of the data to which it points
+ * is undefined.
+ *
+ * @return
+ *    - srtp_err_status_ok            if there were no problems.
+ *    - [other]                  if there was a failure in
+ *                               the cryptographic mechanisms.
+ */
+srtp_err_status_t srtp_protect_rtcp(srtp_t ctx,
+                                    void *rtcp_hdr,
+                                    int *pkt_octet_len);
+
+/**
+ * @brief srtp_protect_rtcp_mki() is the Secure RTCP sender-side packet
+ * processing function that can utilize mki.
+ *
+ * The function call srtp_protect_rtcp(ctx, rtp_hdr, len_ptr) applies
+ * SRTCP protection to the RTCP packet rtcp_hdr (which has length
+ * *len_ptr) using the SRTP session context ctx.  If srtp_err_status_ok is
+ * returned, then rtp_hdr points to the resulting SRTCP packet and
+ * *len_ptr is the number of octets in that packet; otherwise, no
+ * assumptions should be made about the value of either data elements.
+ *
+ * @warning This function assumes that it can write the authentication
+ * tag into the location in memory immediately following the RTCP
+ * packet, and assumes that the RTCP packet is aligned on a 32-bit
+ * boundary.
+ *
+ * @warning This function assumes that it can write SRTP_MAX_TRAILER_LEN+4
+ * into the location in memory immediately following the RTCP packet.
+ * Callers MUST ensure that this much writable memory is available in
+ * the buffer that holds the RTCP packet.
+ *
+ * @param ctx is the SRTP context to use in processing the packet.
+ *
+ * @param rtcp_hdr is a pointer to the RTCP packet (before the call); after
+ * the function returns, it points to the srtp packet.
+ *
+ * @param pkt_octet_len is a pointer to the length in octets of the
+ * complete RTCP packet (header and body) before the function call,
+ * and of the complete SRTCP packet after the call, if srtp_err_status_ok
+ * was returned.  Otherwise, the value of the data to which it points
+ * is undefined.
+ *
+ * @param use_mki is a boolean to tell the system if mki is being used.  If
+ * set to false then will use the first set of session keys.  If set to true
+ * will
+ * use the session keys identified by the mki_index
+ *
+ * @param mki_index integer value specifying which set of session kesy should be
+ * used if use_mki is set to true.
+ *
+ * @return
+ *    - srtp_err_status_ok            if there were no problems.
+ *    - [other]                  if there was a failure in
+ *                               the cryptographic mechanisms.
+ */
+srtp_err_status_t srtp_protect_rtcp_mki(srtp_t ctx,
+                                        void *rtcp_hdr,
+                                        int *pkt_octet_len,
+                                        unsigned int use_mki,
+                                        unsigned int mki_index);
+
+/**
+ * @brief srtp_unprotect_rtcp() is the Secure RTCP receiver-side packet
+ * processing function.
+ *
+ * The function call srtp_unprotect_rtcp(ctx, srtp_hdr, len_ptr)
+ * verifies the Secure RTCP protection of the SRTCP packet pointed to
+ * by srtcp_hdr (which has length *len_ptr), using the SRTP session
+ * context ctx.  If srtp_err_status_ok is returned, then srtcp_hdr points
+ * to the resulting RTCP packet and *len_ptr is the number of octets
+ * in that packet; otherwise, no assumptions should be made about the
+ * value of either data elements.
+ *
+ * @warning This function assumes that the SRTCP packet is aligned on a
+ * 32-bit boundary.
+ *
+ * @param ctx is a pointer to the srtp_t which applies to the
+ * particular packet.
+ *
+ * @param srtcp_hdr is a pointer to the header of the SRTCP packet
+ * (before the call).  After the function returns, it points to the
+ * rtp packet if srtp_err_status_ok was returned; otherwise, the value of
+ * the data to which it points is undefined.
+ *
+ * @param pkt_octet_len is a pointer to the length in octets of the
+ * complete SRTCP packet (header and body) before the function call,
+ * and of the complete rtp packet after the call, if srtp_err_status_ok was
+ * returned.  Otherwise, the value of the data to which it points is
+ * undefined.
+ *
+ * @return
+ *    - srtp_err_status_ok          if the RTCP packet is valid.
+ *    - srtp_err_status_auth_fail   if the SRTCP packet failed the message
+ *                             authentication check.
+ *    - srtp_err_status_replay_fail if the SRTCP packet is a replay (e.g. has
+ *                             already been processed and accepted).
+ *    - [other]  if there has been an error in the cryptographic mechanisms.
+ *
+ */
+srtp_err_status_t srtp_unprotect_rtcp(srtp_t ctx,
+                                      void *srtcp_hdr,
+                                      int *pkt_octet_len);
+
+/**
+ * @brief srtp_unprotect_rtcp() is the Secure RTCP receiver-side packet
+ * processing function.
+ *
+ * The function call srtp_unprotect_rtcp(ctx, srtp_hdr, len_ptr)
+ * verifies the Secure RTCP protection of the SRTCP packet pointed to
+ * by srtcp_hdr (which has length *len_ptr), using the SRTP session
+ * context ctx.  If srtp_err_status_ok is returned, then srtcp_hdr points
+ * to the resulting RTCP packet and *len_ptr is the number of octets
+ * in that packet; otherwise, no assumptions should be made about the
+ * value of either data elements.
+ *
+ * @warning This function assumes that the SRTCP packet is aligned on a
+ * 32-bit boundary.
+ *
+ * @param ctx is a pointer to the srtp_t which applies to the
+ * particular packet.
+ *
+ * @param srtcp_hdr is a pointer to the header of the SRTCP packet
+ * (before the call).  After the function returns, it points to the
+ * rtp packet if srtp_err_status_ok was returned; otherwise, the value of
+ * the data to which it points is undefined.
+ *
+ * @param pkt_octet_len is a pointer to the length in octets of the
+ * complete SRTCP packet (header and body) before the function call,
+ * and of the complete rtp packet after the call, if srtp_err_status_ok was
+ * returned.  Otherwise, the value of the data to which it points is
+ * undefined.
+ *
+ * @param use_mki is a boolean to tell the system if mki is being used.  If
+ * set to false then will use the first set of session keys.  If set to true
+ * will use the session keys identified by the mki_index
+ *
+ * @return
+ *    - srtp_err_status_ok          if the RTCP packet is valid.
+ *    - srtp_err_status_auth_fail   if the SRTCP packet failed the message
+ *                                  authentication check.
+ *    - srtp_err_status_replay_fail if the SRTCP packet is a replay (e.g. has
+ *                                  already been processed and accepted).
+ *    - srtp_err_status_bad_mki     if the MKI in the packet is not a known MKI
+ *                                  id
+ *    - [other]                     if there has been an error in the
+ *                                  cryptographic mechanisms.
+ *
+ */
+srtp_err_status_t srtp_unprotect_rtcp_mki(srtp_t ctx,
+                                          void *srtcp_hdr,
+                                          int *pkt_octet_len,
+                                          unsigned int use_mki);
+
+/**
+ * @}
+ */
+
+/**
+ * @defgroup User data associated to a SRTP session.
+ * @ingroup  SRTP
+ *
+ * @brief Store custom user data within a SRTP session.
+ *
+ * @{
+ */
+
+/**
+ * @brief srtp_set_user_data() stores the given pointer into the SRTP
+ * session for later retrieval.
+ *
+ * @param ctx is the srtp_t context in which the given data pointer is
+ * stored.
+ *
+ * @param data is a pointer to the custom information (struct, function,
+ * etc) associated with the SRTP session.
+ *
+ * @return void.
+ *
+ */
+void srtp_set_user_data(srtp_t ctx, void *data);
+
+/**
+ * @brief srtp_get_user_data() retrieves the pointer to the custom data
+ * previously stored with srtp_set_user_data().
+ *
+ * This function is mostly useful for retrieving data associated to a
+ * SRTP session when an event fires. The user can then get such a custom
+ * data by calling this function with the session field of the
+ * srtp_event_data_t struct as argument.
+ *
+ * @param ctx is the srtp_t context in which the given data pointer was
+ * stored.
+ *
+ * @return void* pointer to the user data.
+ *
+ */
+void *srtp_get_user_data(srtp_t ctx);
+
+/**
+ * @}
+ */
+
+/**
+ * @defgroup SRTPevents SRTP events and callbacks
+ * @ingroup  SRTP
+ *
+ * @brief libSRTP can use a user-provided callback function to
+ * handle events.
+ *
+ *
+ * libSRTP allows a user to provide a callback function to handle
+ * events that need to be dealt with outside of the data plane (see
+ * the enum srtp_event_t for a description of these events).  Dealing
+ * with these events is not a strict necessity; they are not
+ * security-critical, but the application may suffer if they are not
+ * handled.  The function srtp_set_event_handler() is used to provide
+ * the callback function.
+ *
+ * A default event handler that merely reports on the events as they
+ * happen is included.  It is also possible to set the event handler
+ * function to NULL, in which case all events will just be silently
+ * ignored.
+ *
+ * @{
+ */
+
+/**
+ * @brief srtp_event_t defines events that need to be handled
+ *
+ * The enum srtp_event_t defines events that need to be handled
+ * outside the `data plane', such as SSRC collisions and
+ * key expirations.
+ *
+ * When a key expires or the maximum number of packets has been
+ * reached, an SRTP stream will enter an `expired' state in which no
+ * more packets can be protected or unprotected.  When this happens,
+ * it is likely that you will want to either deallocate the stream
+ * (using srtp_remove_stream()), and possibly allocate a new one.
+ *
+ * When an SRTP stream expires, the other streams in the same session
+ * are unaffected, unless key sharing is used by that stream.  In the
+ * latter case, all of the streams in the session will expire.
+ */
+typedef enum {
+    event_ssrc_collision,    /**< An SSRC collision occured.            */
+    event_key_soft_limit,    /**< An SRTP stream reached the soft key   */
+                             /**< usage limit and will expire soon.     */
+    event_key_hard_limit,    /**< An SRTP stream reached the hard       */
+                             /**< key usage limit and has expired.      */
+    event_packet_index_limit /**< An SRTP stream reached the hard       */
+                             /**< packet limit (2^48 packets).          */
+} srtp_event_t;
+
+/**
+ * @brief srtp_event_data_t is the structure passed as a callback to
+ * the event handler function
+ *
+ * The struct srtp_event_data_t holds the data passed to the event
+ * handler function.
+ */
+typedef struct srtp_event_data_t {
+    srtp_t session;     /**< The session in which the event happend.        */
+    uint32_t ssrc;      /**< The ssrc in host order of the stream in which  */
+                        /**< the event happend                              */
+    srtp_event_t event; /**< An enum indicating the type of event.          */
+} srtp_event_data_t;
+
+/**
+ * @brief srtp_event_handler_func_t is the function prototype for
+ * the event handler.
+ *
+ * The typedef srtp_event_handler_func_t is the prototype for the
+ * event handler function.  It has as its only argument an
+ * srtp_event_data_t which describes the event that needs to be handled.
+ * There can only be a single, global handler for all events in
+ * libSRTP.
+ */
+typedef void(srtp_event_handler_func_t)(srtp_event_data_t *data);
+
+/**
+ * @brief sets the event handler to the function supplied by the caller.
+ *
+ * The function call srtp_install_event_handler(func) sets the event
+ * handler function to the value func.  The value NULL is acceptable
+ * as an argument; in this case, events will be ignored rather than
+ * handled.
+ *
+ * @param func is a pointer to a fuction that takes an srtp_event_data_t
+ *             pointer as an argument and returns void.  This function
+ *             will be used by libSRTP to handle events.
+ */
+srtp_err_status_t srtp_install_event_handler(srtp_event_handler_func_t func);
+
+/**
+ * @brief Returns the version string of the library.
+ *
+ */
+const char *srtp_get_version_string(void);
+
+/**
+ * @brief Returns the numeric representation of the library version.
+ *
+ */
+unsigned int srtp_get_version(void);
+
+/**
+ * @brief srtp_set_debug_module(mod_name, v)
+ *
+ * sets dynamic debugging to the value v (0 for off, 1 for on) for the
+ * debug module with the name mod_name
+ *
+ * returns err_status_ok on success, err_status_fail otherwise
+ */
+srtp_err_status_t srtp_set_debug_module(const char *mod_name, int v);
+
+/**
+ * @brief srtp_list_debug_modules() outputs a list of debugging modules
+ *
+ */
+srtp_err_status_t srtp_list_debug_modules(void);
+
+/**
+ * @brief srtp_log_level_t defines log levels.
+ *
+ * The enumeration srtp_log_level_t defines log levels reported
+ * in the srtp_log_handler_func_t.
+ *
+ */
+typedef enum {
+    srtp_log_level_error,   /**< log level is reporting an error message  */
+    srtp_log_level_warning, /**< log level is reporting a warning message */
+    srtp_log_level_info,    /**< log level is reporting an info message   */
+    srtp_log_level_debug    /**< log level is reporting a debug message   */
+} srtp_log_level_t;
+
+/**
+ * @brief srtp_log_handler_func_t is the function prototype for
+ * the log handler.
+ *
+ * The typedef srtp_event_handler_func_t is the prototype for the
+ * event handler function.  It has as srtp_log_level_t, log
+ * message and data as arguments.
+ * There can only be a single, global handler for all log messages in
+ * libSRTP.
+ */
+typedef void(srtp_log_handler_func_t)(srtp_log_level_t level,
+                                      const char *msg,
+                                      void *data);
+
+/**
+ * @brief sets the log handler to the function supplied by the caller.
+ *
+ * The function call srtp_install_log_handler(func) sets the log
+ * handler function to the value func.  The value NULL is acceptable
+ * as an argument; in this case, log messages will be ignored.
+ * This function can be called before srtp_init() inorder to capture
+ * any logging during start up.
+ *
+ * @param func is a pointer to a fuction of type srtp_log_handler_func_t.
+ *             This function will be used by libSRTP to output log messages.
+ * @param data is a user pointer that will be returned as the data argument in
+ * func.
+ */
+srtp_err_status_t srtp_install_log_handler(srtp_log_handler_func_t func,
+                                           void *data);
+
+/**
+ * @brief srtp_get_protect_trailer_length(session, use_mki, mki_index, length)
+ *
+ * Determines the length of the amount of data Lib SRTP will add to the
+ * packet during the protect process. The length is returned in the length
+ * parameter
+ *
+ * returns err_status_ok on success, err_status_bad_mki if the MKI index is
+ * invalid
+ *
+ */
+srtp_err_status_t srtp_get_protect_trailer_length(srtp_t session,
+                                                  uint32_t use_mki,
+                                                  uint32_t mki_index,
+                                                  uint32_t *length);
+
+/**
+ * @brief srtp_get_protect_rtcp_trailer_length(session, use_mki, mki_index,
+ * length)
+ *
+ * Determines the length of the amount of data Lib SRTP will add to the
+ * packet during the protect process. The length is returned in the length
+ * parameter
+ *
+ * returns err_status_ok on success, err_status_bad_mki if the MKI index is
+ * invalid
+ *
+ */
+srtp_err_status_t srtp_get_protect_rtcp_trailer_length(srtp_t session,
+                                                       uint32_t use_mki,
+                                                       uint32_t mki_index,
+                                                       uint32_t *length);
+
+/**
+ * @brief srtp_set_stream_roc(session, ssrc, roc)
+ *
+ * Set the roll-over-counter on a session for a given SSRC
+ *
+ * returns err_status_ok on success, srtp_err_status_bad_param if there is no
+ * stream found
+ *
+ */
+srtp_err_status_t srtp_set_stream_roc(srtp_t session,
+                                      uint32_t ssrc,
+                                      uint32_t roc);
+
+/**
+ * @brief srtp_get_stream_roc(session, ssrc, roc)
+ *
+ * Get the roll-over-counter on a session for a given SSRC
+ *
+ * returns err_status_ok on success, srtp_err_status_bad_param if there is no
+ * stream found
+ *
+ */
+srtp_err_status_t srtp_get_stream_roc(srtp_t session,
+                                      uint32_t ssrc,
+                                      uint32_t *roc);
+
+/**
+ * @}
+ */
+
+/* in host order, so outside the #if */
+#define SRTCP_E_BIT 0x80000000
+
+/* for byte-access */
+#define SRTCP_E_BYTE_BIT 0x80
+#define SRTCP_INDEX_MASK 0x7fffffff
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SRTP_SRTP_H */
diff --git a/netwerk/srtp/src/include/srtp_priv.h b/netwerk/srtp/src/include/srtp_priv.h
new file mode 100644
index 0000000000..988efc4164
--- /dev/null
+++ b/netwerk/srtp/src/include/srtp_priv.h
@@ -0,0 +1,280 @@
+/*
+ * srtp_priv.h
+ *
+ * private internal data structures and functions for libSRTP
+ *
+ * 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 SRTP_PRIV_H
+#define SRTP_PRIV_H
+
+// Leave this as the top level import. Ensures the existence of defines
+#include "config.h"
+
+#include "srtp.h"
+#include "rdbx.h"
+#include "rdb.h"
+#include "integers.h"
+#include "cipher.h"
+#include "auth.h"
+#include "aes.h"
+#include "key.h"
+#include "crypto_kernel.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define SRTP_VER_STRING PACKAGE_STRING
+#define SRTP_VERSION PACKAGE_VERSION
+
+typedef struct srtp_stream_ctx_t_ srtp_stream_ctx_t;
+typedef srtp_stream_ctx_t *srtp_stream_t;
+
+/*
+ * the following declarations are libSRTP internal functions
+ */
+
+/*
+ * srtp_get_stream(ssrc) returns a pointer to the stream corresponding
+ * to ssrc, or NULL if no stream exists for that ssrc
+ */
+srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
+
+/*
+ * srtp_stream_init_keys(s, k) (re)initializes the srtp_stream_t s by
+ * deriving all of the needed keys using the KDF and the key k.
+ */
+srtp_err_status_t srtp_stream_init_keys(srtp_stream_ctx_t *srtp,
+                                        srtp_master_key_t *master_key,
+                                        const unsigned int current_mki_index);
+
+/*
+ * srtp_stream_init_all_master_keys(s, k, m) (re)initializes the srtp_stream_t s
+ * by deriving all of the needed keys for all the master keys using the KDF and
+ * the keys from k.
+ */
+srtp_err_status_t srtp_steam_init_all_master_keys(
+    srtp_stream_ctx_t *srtp,
+    unsigned char *key,
+    srtp_master_key_t **keys,
+    const unsigned int max_master_keys);
+
+/*
+ * srtp_stream_init(s, p) initializes the srtp_stream_t s to
+ * use the policy at the location p
+ */
+srtp_err_status_t srtp_stream_init(srtp_stream_t srtp, const srtp_policy_t *p);
+
+/*
+ * libsrtp internal datatypes
+ */
+typedef enum direction_t {
+    dir_unknown = 0,
+    dir_srtp_sender = 1,
+    dir_srtp_receiver = 2
+} direction_t;
+
+/*
+ * srtp_session_keys_t will contain the encryption, hmac, salt keys
+ * for both SRTP and SRTCP.  The session keys will also contain the
+ * MKI ID which is used to identify the session keys.
+ */
+typedef struct srtp_session_keys_t {
+    srtp_cipher_t *rtp_cipher;
+    srtp_cipher_t *rtp_xtn_hdr_cipher;
+    srtp_auth_t *rtp_auth;
+    srtp_cipher_t *rtcp_cipher;
+    srtp_auth_t *rtcp_auth;
+    uint8_t salt[SRTP_AEAD_SALT_LEN];
+    uint8_t c_salt[SRTP_AEAD_SALT_LEN];
+    uint8_t *mki_id;
+    unsigned int mki_size;
+    srtp_key_limit_ctx_t *limit;
+} srtp_session_keys_t;
+
+/*
+ * an srtp_stream_t has its own SSRC, encryption key, authentication
+ * key, sequence number, and replay database
+ *
+ * note that the keys might not actually be unique, in which case the
+ * srtp_cipher_t and srtp_auth_t pointers will point to the same structures
+ */
+typedef struct srtp_stream_ctx_t_ {
+    uint32_t ssrc;
+    srtp_session_keys_t *session_keys;
+    unsigned int num_master_keys;
+    srtp_rdbx_t rtp_rdbx;
+    srtp_sec_serv_t rtp_services;
+    srtp_rdb_t rtcp_rdb;
+    srtp_sec_serv_t rtcp_services;
+    direction_t direction;
+    int allow_repeat_tx;
+    srtp_ekt_stream_t ekt;
+    int *enc_xtn_hdr;
+    int enc_xtn_hdr_count;
+    uint32_t pending_roc;
+    struct srtp_stream_ctx_t_ *next; /* linked list of streams */
+} strp_stream_ctx_t_;
+
+/*
+ * an srtp_ctx_t holds a stream list and a service description
+ */
+typedef struct srtp_ctx_t_ {
+    struct srtp_stream_ctx_t_ *stream_list;     /* linked list of streams     */
+    struct srtp_stream_ctx_t_ *stream_template; /* act as template for other  */
+                                                /* streams                    */
+    void *user_data;                            /* user custom data           */
+} srtp_ctx_t_;
+
+/*
+ * srtp_hdr_t represents an RTP or SRTP header.  The bit-fields in
+ * this structure should be declared "unsigned int" instead of
+ * "unsigned char", but doing so causes the MS compiler to not
+ * fully pack the bit fields.
+ *
+ * In this implementation, an srtp_hdr_t is assumed to be 32-bit aligned
+ *
+ * (note that this definition follows that of RFC 1889 Appendix A, but
+ * is not identical)
+ */
+
+#ifndef WORDS_BIGENDIAN
+
+typedef struct {
+    unsigned char cc : 4;      /* CSRC count             */
+    unsigned char x : 1;       /* header extension flag  */
+    unsigned char p : 1;       /* padding flag           */
+    unsigned char version : 2; /* protocol version       */
+    unsigned char pt : 7;      /* payload type           */
+    unsigned char m : 1;       /* marker bit             */
+    uint16_t seq;              /* sequence number        */
+    uint32_t ts;               /* timestamp              */
+    uint32_t ssrc;             /* synchronization source */
+} srtp_hdr_t;
+
+#else /*  BIG_ENDIAN */
+
+typedef struct {
+    unsigned char version : 2; /* protocol version       */
+    unsigned char p : 1;       /* padding flag           */
+    unsigned char x : 1;       /* header extension flag  */
+    unsigned char cc : 4;      /* CSRC count             */
+    unsigned char m : 1;       /* marker bit             */
+    unsigned char pt : 7;      /* payload type           */
+    uint16_t seq;              /* sequence number        */
+    uint32_t ts;               /* timestamp              */
+    uint32_t ssrc;             /* synchronization source */
+} srtp_hdr_t;
+
+#endif
+
+typedef struct {
+    uint16_t profile_specific; /* profile-specific info               */
+    uint16_t length;           /* number of 32-bit words in extension */
+} srtp_hdr_xtnd_t;
+
+/*
+ * srtcp_hdr_t represents a secure rtcp header
+ *
+ * in this implementation, an srtcp header is assumed to be 32-bit
+ * alinged
+ */
+
+#ifndef WORDS_BIGENDIAN
+
+typedef struct {
+    unsigned char rc : 5;      /* reception report count */
+    unsigned char p : 1;       /* padding flag           */
+    unsigned char version : 2; /* protocol version       */
+    unsigned char pt : 8;      /* payload type           */
+    uint16_t len;              /* length                 */
+    uint32_t ssrc;             /* synchronization source */
+} srtcp_hdr_t;
+
+typedef struct {
+    unsigned int index : 31; /* srtcp packet index in network order!  */
+    unsigned int e : 1;      /* encrypted? 1=yes                      */
+                             /* optional mikey/etc go here            */
+                             /* and then the variable-length auth tag */
+} srtcp_trailer_t;
+
+#else /*  BIG_ENDIAN */
+
+typedef struct {
+    unsigned char version : 2; /* protocol version       */
+    unsigned char p : 1;       /* padding flag           */
+    unsigned char rc : 5;      /* reception report count */
+    unsigned char pt : 8;      /* payload type           */
+    uint16_t len;              /* length                 */
+    uint32_t ssrc;             /* synchronization source */
+} srtcp_hdr_t;
+
+typedef struct {
+    unsigned int e : 1;      /* encrypted? 1=yes                      */
+    unsigned int index : 31; /* srtcp packet index                    */
+                             /* optional mikey/etc go here            */
+                             /* and then the variable-length auth tag */
+} srtcp_trailer_t;
+
+#endif
+
+/*
+ * srtp_handle_event(srtp, srtm, evnt) calls the event handling
+ * function, if there is one.
+ *
+ * This macro is not included in the documentation as it is
+ * an internal-only function.
+ */
+
+#define srtp_handle_event(srtp, strm, evnt)                                    \
+    if (srtp_event_handler) {                                                  \
+        srtp_event_data_t data;                                                \
+        data.session = srtp;                                                   \
+        data.ssrc = ntohl(strm->ssrc);                                         \
+        data.event = evnt;                                                     \
+        srtp_event_handler(&data);                                             \
+    }
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SRTP_PRIV_H */
diff --git a/netwerk/srtp/src/include/ut_sim.h b/netwerk/srtp/src/include/ut_sim.h
new file mode 100644
index 0000000000..e678b5fdf7
--- /dev/null
+++ b/netwerk/srtp/src/include/ut_sim.h
@@ -0,0 +1,83 @@
+/*
+ * ut-sim.h
+ *
+ * an unreliable transport simulator
+ * (for testing replay databases and suchlike)
+ *
+ * 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 UT_SIM_H
+#define UT_SIM_H
+
+#include "integers.h" /* for uint32_t */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define UT_BUF 160 /* maximum amount of packet reorder */
+
+typedef struct {
+    uint32_t index;
+    uint32_t buffer[UT_BUF];
+} ut_connection;
+
+/*
+ * ut_init(&u) initializes the ut_connection
+ *
+ * this function should always be the first one called on a new
+ * ut_connection
+ */
+
+void ut_init(ut_connection *utc);
+
+/*
+ * ut_next_index(&u) returns the next index from the simulated
+ * unreliable connection
+ */
+
+uint32_t ut_next_index(ut_connection *utc);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* UT_SIM_H */