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/*
* 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 "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;
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
* aligned
*/
#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 */
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