281 lines
9.4 KiB
C
281 lines
9.4 KiB
C
/*
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* srtp_priv.h
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*
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* private internal data structures and functions for libSRTP
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*
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* David A. McGrew
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* Cisco Systems, Inc.
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*/
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/*
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*
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* Copyright (c) 2001-2017 Cisco Systems, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#ifndef SRTP_PRIV_H
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#define SRTP_PRIV_H
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// Leave this as the top level import. Ensures the existence of defines
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#include "config.h"
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#include "srtp.h"
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#include "rdbx.h"
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#include "rdb.h"
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#include "integers.h"
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#include "cipher.h"
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#include "auth.h"
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#include "aes.h"
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#include "key.h"
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#include "crypto_kernel.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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#define SRTP_VER_STRING "libsrtp2 2.1.0-pre"
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#define SRTP_VERSION "2.1.0-pre"
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typedef struct srtp_stream_ctx_t_ srtp_stream_ctx_t;
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typedef srtp_stream_ctx_t *srtp_stream_t;
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/*
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* the following declarations are libSRTP internal functions
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*/
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/*
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* srtp_get_stream(ssrc) returns a pointer to the stream corresponding
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* to ssrc, or NULL if no stream exists for that ssrc
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*/
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srtp_stream_t srtp_get_stream(srtp_t srtp, uint32_t ssrc);
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/*
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* srtp_stream_init_keys(s, k) (re)initializes the srtp_stream_t s by
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* deriving all of the needed keys using the KDF and the key k.
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*/
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srtp_err_status_t srtp_stream_init_keys(srtp_stream_ctx_t *srtp,
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srtp_master_key_t *master_key,
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const unsigned int current_mki_index);
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/*
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* srtp_stream_init_all_master_keys(s, k, m) (re)initializes the srtp_stream_t s
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* by deriving all of the needed keys for all the master keys using the KDF and
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* the keys from k.
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*/
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srtp_err_status_t srtp_steam_init_all_master_keys(
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srtp_stream_ctx_t *srtp,
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unsigned char *key,
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srtp_master_key_t **keys,
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const unsigned int max_master_keys);
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/*
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* srtp_stream_init(s, p) initializes the srtp_stream_t s to
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* use the policy at the location p
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*/
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srtp_err_status_t srtp_stream_init(srtp_stream_t srtp, const srtp_policy_t *p);
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/*
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* libsrtp internal datatypes
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*/
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typedef enum direction_t {
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dir_unknown = 0,
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dir_srtp_sender = 1,
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dir_srtp_receiver = 2
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} direction_t;
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/*
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* srtp_session_keys_t will contain the encryption, hmac, salt keys
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* for both SRTP and SRTCP. The session keys will also contain the
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* MKI ID which is used to identify the session keys.
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*/
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typedef struct srtp_session_keys_t {
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srtp_cipher_t *rtp_cipher;
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srtp_cipher_t *rtp_xtn_hdr_cipher;
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srtp_auth_t *rtp_auth;
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srtp_cipher_t *rtcp_cipher;
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srtp_auth_t *rtcp_auth;
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uint8_t salt[SRTP_AEAD_SALT_LEN];
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uint8_t c_salt[SRTP_AEAD_SALT_LEN];
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uint8_t *mki_id;
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unsigned int mki_size;
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srtp_key_limit_ctx_t *limit;
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} srtp_session_keys_t;
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/*
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* an srtp_stream_t has its own SSRC, encryption key, authentication
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* key, sequence number, and replay database
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*
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* note that the keys might not actually be unique, in which case the
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* srtp_cipher_t and srtp_auth_t pointers will point to the same structures
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*/
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typedef struct srtp_stream_ctx_t_ {
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uint32_t ssrc;
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srtp_session_keys_t *session_keys;
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unsigned int num_master_keys;
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srtp_rdbx_t rtp_rdbx;
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srtp_sec_serv_t rtp_services;
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srtp_rdb_t rtcp_rdb;
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srtp_sec_serv_t rtcp_services;
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direction_t direction;
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int allow_repeat_tx;
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srtp_ekt_stream_t ekt;
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int *enc_xtn_hdr;
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int enc_xtn_hdr_count;
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uint32_t pending_roc;
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struct srtp_stream_ctx_t_ *next; /* linked list of streams */
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} strp_stream_ctx_t_;
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/*
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* an srtp_ctx_t holds a stream list and a service description
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*/
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typedef struct srtp_ctx_t_ {
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struct srtp_stream_ctx_t_ *stream_list; /* linked list of streams */
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struct srtp_stream_ctx_t_ *stream_template; /* act as template for other */
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/* streams */
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void *user_data; /* user custom data */
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} srtp_ctx_t_;
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/*
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* srtp_hdr_t represents an RTP or SRTP header. The bit-fields in
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* this structure should be declared "unsigned int" instead of
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* "unsigned char", but doing so causes the MS compiler to not
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* fully pack the bit fields.
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*
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* In this implementation, an srtp_hdr_t is assumed to be 32-bit aligned
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*
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* (note that this definition follows that of RFC 1889 Appendix A, but
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* is not identical)
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*/
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#ifndef WORDS_BIGENDIAN
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typedef struct {
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unsigned char cc : 4; /* CSRC count */
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unsigned char x : 1; /* header extension flag */
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unsigned char p : 1; /* padding flag */
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unsigned char version : 2; /* protocol version */
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unsigned char pt : 7; /* payload type */
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unsigned char m : 1; /* marker bit */
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uint16_t seq; /* sequence number */
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uint32_t ts; /* timestamp */
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uint32_t ssrc; /* synchronization source */
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} srtp_hdr_t;
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#else /* BIG_ENDIAN */
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typedef struct {
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unsigned char version : 2; /* protocol version */
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unsigned char p : 1; /* padding flag */
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unsigned char x : 1; /* header extension flag */
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unsigned char cc : 4; /* CSRC count */
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unsigned char m : 1; /* marker bit */
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unsigned char pt : 7; /* payload type */
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uint16_t seq; /* sequence number */
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uint32_t ts; /* timestamp */
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uint32_t ssrc; /* synchronization source */
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} srtp_hdr_t;
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#endif
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typedef struct {
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uint16_t profile_specific; /* profile-specific info */
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uint16_t length; /* number of 32-bit words in extension */
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} srtp_hdr_xtnd_t;
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/*
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* srtcp_hdr_t represents a secure rtcp header
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*
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* in this implementation, an srtcp header is assumed to be 32-bit
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* alinged
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*/
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#ifndef WORDS_BIGENDIAN
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typedef struct {
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unsigned char rc : 5; /* reception report count */
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unsigned char p : 1; /* padding flag */
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unsigned char version : 2; /* protocol version */
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unsigned char pt : 8; /* payload type */
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uint16_t len; /* length */
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uint32_t ssrc; /* synchronization source */
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} srtcp_hdr_t;
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typedef struct {
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unsigned int index : 31; /* srtcp packet index in network order! */
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unsigned int e : 1; /* encrypted? 1=yes */
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/* optional mikey/etc go here */
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/* and then the variable-length auth tag */
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} srtcp_trailer_t;
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#else /* BIG_ENDIAN */
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typedef struct {
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unsigned char version : 2; /* protocol version */
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unsigned char p : 1; /* padding flag */
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unsigned char rc : 5; /* reception report count */
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unsigned char pt : 8; /* payload type */
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uint16_t len; /* length */
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uint32_t ssrc; /* synchronization source */
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} srtcp_hdr_t;
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typedef struct {
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unsigned int e : 1; /* encrypted? 1=yes */
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unsigned int index : 31; /* srtcp packet index */
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/* optional mikey/etc go here */
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/* and then the variable-length auth tag */
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} srtcp_trailer_t;
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#endif
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/*
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* srtp_handle_event(srtp, srtm, evnt) calls the event handling
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* function, if there is one.
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*
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* This macro is not included in the documentation as it is
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* an internal-only function.
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*/
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#define srtp_handle_event(srtp, strm, evnt) \
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if (srtp_event_handler) { \
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srtp_event_data_t data; \
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data.session = srtp; \
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data.ssrc = ntohl(strm->ssrc); \
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data.event = evnt; \
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srtp_event_handler(&data); \
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}
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#ifdef __cplusplus
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}
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#endif
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#endif /* SRTP_PRIV_H */
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