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/*
* libZRTP SDK library, implements the ZRTP secure VoIP protocol.
* Copyright (c) 2006-2009 Philip R. Zimmermann. All rights reserved.
* Contact: http://philzimmermann.com
* For licensing and other legal details, see the file zrtp_legal.c.
*
* Viktor Krykun <v.krikun at zfoneproject.com>
*/
/**
* \file zrtp.h
* \brief Defines basic libzrtp functions and data types
*/
#ifndef __ZRTP_H__
#define __ZRTP_H__
#include "zrtp_config.h"
#include "zrtp_base.h"
#include "zrtp_error.h"
#include "zrtp_types.h"
#include "zrtp_protocol.h"
#include "zrtp_engine.h"
#include "zrtp_crypto.h"
#include "zrtp_iface.h"
#include "zrtp_iface_system.h"
#include "zrtp_iface_scheduler.h"
#include "zrtp_list.h"
#include "zrtp_legal.h"
#include "zrtp_log.h"
#include "zrtp_srtp.h"
#include "zrtp_srtp_builtin.h"
#include "zrtp_string.h"
#include "zrtp_pbx.h"
#include "zrtp_legal.h"
#include "zrtp_version.h"
#include "zrtp_iface_cache.h"
#if (defined(ZRTP_ENABLE_EC) && (ZRTP_ENABLE_EC == 1))
#include "zrtp_ec.h"
#endif
/**
* \defgroup zrtp_api API
*
* In this section the basic functions for using the library are defined. They include
* initialization and deinitialization functions, functions for session and stream management and
* functions for RTP traffic management.
*
* In most cases this section is all you need to start working with libzrtp. The typical simplified
* order of operations in using libzrtp is the following:
* -# library configuration
* -# library initialization;
* -# ZRTP session creation and configuration;
* -# ZRTP stream attaching and Protocol initiation;
* -# RTP stream processing;
* -# ZRTP protocol stopping and releasing resources.
* For each of these actions there is a set of corresponding functions.
* \sa
* - \ref howto
* - \ref XXX_GUIDE
*/
/*======================================================================*/
/* Public ZRTP libzrtp datatypes */
/*======================================================================*/
/**
* \defgroup zrtp_types Types and Definitions
* \ingroup zrtp_api
* The data types used in libzrtp are defined in this section
* \{
*
*/
/**
* \typedef typedef uint32_t zrtp_id_t;
* \brief libzrtp general identifier used to debug connections management.
* \ingroup zrtp_main_init
*/
/**
* \brief Enumeration for ZRTP Licensing modes
* \ingroup zrtp_main_init
*
* A ZRTP endpoint that is Passive will never send a Commit message, which means that it cannot be
* the initiator in the ZRTP exchange. Since at least one of the two parties must be the initiator,
* two Passive endpoints cannot make a secure connection. However, a non-Passive ZRTP endpoint can
* send a Commit message, enabling it to act as the initiator in a ZRTP exchange. This allows it to
* make a secure connection to a Passive endpoint, or to another non-Passive endpoint.
*
* In addition, a Passive ZRTP endpoint declares that it is Passive by setting the passive flag in
* the Hello message, which means the other party will recognize it as Passive. This allows for a
* Passive mode and two forms of Active mode-- Active, or Unlimited. These three possible behaviors
* for a ZRTP endpoint are defined as:
* - \b Passive: Never send a Commit message, and thus can never be the initiator.
* - \b Active: Will send a Commit message, but only to non-Passive ZRTP partners.
* - \b Unlimited: Will send a Commit message to any ZRTP partner, Passive or non-Passive.
*
* This can be used to provide three classes of service, which can be licensed t different price
* points. Passive can be used in freeware for widest possible deployment, Active can be used in
* discount products that can only talk to non-freeware, and Unlimited can be used in full-price
* products that will benefit from the network effect of widely deployed Passive freeware.
*/
typedef enum zrtp_license_mode_t
{
/** @brief Never send a Commit message, and thus can never be the initiator. */
ZRTP_LICENSE_MODE_PASSIVE = 0,
/** @brief Will initiate ZRTP exchange, but only to non-Passive ZRTP partners. */
ZRTP_LICENSE_MODE_ACTIVE,
/** @brief Will send a Commit message to any ZRTP partner, Passive or non-Passive. */
ZRTP_LICENSE_MODE_UNLIMITED
} zrtp_license_mode_t;
/** @brief 12-byte ZID for unique ZRTP endpoint identification. */
typedef unsigned char zrtp_zid_t[12];
/** \brief 16-byte ID for ZRTP endpoint's software identification. */
typedef char zrtp_client_id_t[16];
/**
* \brief ZRTP global configuration options
* \ingroup zrtp_main_init
* \warning Use \ref zrtp_config_defaults() before start configuring this structure.
*/
typedef struct zrtp_config_t
{
/** @brief Symbolic client identifier */
zrtp_client_id_t client_id;
/** @brief libzrtp license mode defined protocol behavior */
zrtp_license_mode_t lic_mode;
/** @brief Set this flag to 1 if you product is MiTM box */
uint8_t is_mitm;
/** @brief Set of interfaces required to operate with libzrtp */
zrtp_callback_t cb;
/** @brief Path to zrtp cache file (set if you use built-in realization) */
zrtp_string256_t def_cache_path;
} zrtp_config_t;
/**
* \brief zrtp stream information structure
* \ingroup zrtp_main_management
*
* libzrtp, since v0.80 takes data incapsulating approach and hides all private date inside
* zrtp_stream_t structure. Developers shouldn't access them directly. \ref zrtp_stream_get() should
* be used instead to fill zrtp_stream_info_t structure. zrtp_stream_info_t contains all needed
* information in safe and easy to use form.
*/
struct zrtp_stream_info_t
{
/** \brief Stream unique identifier for debug purposes */
zrtp_id_t id;
/** \brief Pointer to the parent zrtp session */
zrtp_session_t* session;
/** \brief Stream mode. Defines libzrtp behavior related to specified contexts. */
zrtp_stream_mode_t mode;
/** \brief Defines ZRTP Trusted mitm mode for the current session. */
zrtp_mitm_mode_t mitm_mode;
/** \brief Reflects current state of ZRTP protocol */
zrtp_state_t state;
/**
* \brief Last protocol error code
*
* Available for reading in ERROR state on zrtp_security_event_t#ZRTP_EVENT_PROTOCOL_ERROR.
*/
zrtp_protocol_error_t last_error;
/**
* \brief Remote passive flag
*
* This flag shows when remote side is "passive" (has license mode PASSIVE) available in CLEAR
* state and later.
*/
uint8_t peer_passive;
/**
* \brief Allowclear flag.
*
* Current value of "allowclear" option exchanged during ZRTP negotiation. Available in SECURE
* state.
*/
uint8_t res_allowclear;
/**
* \brief Peer disclose bit flag
*
* Indicates the ability of the remote side to disclose its session key. Specifies that the
* remote side allows call monitoring. If this flag is set, the end user must be informed. It
* can be read in the SECURE state.
*/
uint8_t peer_disclose;
/**
* \brief Defines that remote party is ZRTP MiTM endpoint
*
* Enabled by (Asterisk PBX, UMLab SIP Firewall or etc.) Available for reading in CLEAR state
* ande later.
*/
uint8_t peer_mitm;
};
/**
* \brief zrtp session information structure
* \ingroup zrtp_main_management
* libzrtp, since v0.80 takes data incapsulating approach and hides all private date inside
* zrtp_session_t structure. Developers shouldn't access them directly. \ref zrtp_session_get()
* should be used instead to fill zrtp_session_info_t structure. zrtp_session_info_t contains all
* needed information in safe and easy to use form.
*/
struct zrtp_session_info_t
{
/** \brief Session unique identifier for debug purposes */
zrtp_id_t id;
/**
* \brief Local ZID
*
The unique 12-characters string that identifies the local ZRTP endpoint.This ID allows remote
* peers to recognize this ZRTP endpoint.
*/
zrtp_string16_t zid;
/**
* \brief Remote ZID
*
* Extracted from the Hello packet of the very first ZRTP stream. Uniquely identifies the remote
* ZRTP peer.
*/
zrtp_string16_t peer_zid;
/** \brief Character name identified remote ZRTP endpoint.*/
zrtp_string16_t peer_clientid;
/** \brief ZRTP Protocol version supported by the remote endpoint. */
zrtp_string16_t peer_version;
/**
* \brief Indicates that SAS related data is available for reading.
* \note
* As SAS is computed in SECURE state only, it may contain unknown values in other states. Check
* sas_is_ready before displaying SAS to the user.
*/
uint8_t sas_is_ready;
/** \brief First Short Authentication String */
zrtp_string16_t sas1;
/**
* \brief Second Short Authentication string.
* \note
* Second SAS is available for \c base256 authentication only (\c sas_is_base256 is set). In
* other case, \c sas1 contains \c base32 value and \c sas2 is empty.
*/
zrtp_string16_t sas2;
/** \brief Binary SAS digest (ZRTP_SAS_DIGEST_LENGTH bytes) */
zrtp_string32_t sasbin;
/**
* \brief Bit-map to summarize shared secrets "Cached" flags.
*
* 1 at appropriate bit means that the secrets was found in the cache and restored successfully.
* Value equal to 0 indicates that secret for the remote endpoint was not found in the cache
* and was generated randomly.
* Use ZRTP_BIT_RS1, ZRTP_BIT_RS2, ZRTP_BIT_AUX and ZRTP_BIT_PBX bit-masks to get "cached" value
* for the appropriate secret.
*/
uint32_t cached_flags;
/**
* \brief Bit-map to summarize shared secrets "Matched" flags.
*
* 1 at appropriate bit means that the secret, locally computed by your ZRTP endpoint is equal
* to the secret, received from the remote endpoint. Secrets may not match if one of the
* endpoints doesn't use cache of the shared secrets, if the cache was deleted or in case of
* an attack.
* Use ZRTP_BIT_RS1, ZRTP_BIT_RS2, ZRTP_BIT_AUX and ZRTP_BIT_PBX bit-masks to get "cached" value
* for the appropriate secret.
*/
uint32_t matches_flags;
/**
* \brief Bit-map to summarize shared secrets "Wrong" flags.
*
* 1 at appropriate bit means that the secret was restored from the cache, but doesn't match
* to the remote endpoint's secret. Such situation may happen if the remote endpoint lost cache
* or in case of attach.
* Use ZRTP_BIT_RS1, ZRTP_BIT_RS2, ZRTP_BIT_AUX and ZRTP_BIT_PBX bit-masks to get "cached" value
* for the appropriate secret.
*/
uint32_t wrongs_flags;
/**
* \brief SAS Verification flag.
*
* The SAS Verified flag (V) is set based on the user indicating that SAS comparison has been
* successfully performed. Each party sends the SAS Verified flag from the previous session in
* the Confirm message of the current session.
* \sa
* - ZRTP RFC section. "7.1. SAS Verified Flag" for more information about Verification Flag.
* - zrtp_verified_set()
*/
uint32_t sas_is_verified;
/** \brief Indicates base256 SAS encoding */
uint8_t sas_is_base256;
/**
* \brief actual lifetime of the secrets
*
* This variable contains the interval for retaining secrets within an established session. In
* accordance with ZRTP RFC this value is calculated as the minimal of local and remote TTLs
* after confirmation. Value is given in seconds and can be read in the SECURE state.
*/
uint32_t secrets_ttl;
/** \brief Hash crypto component name used in ZRTP calculations. */
zrtp_string32_t hash_name;
/** \brief Cipher crypto component name used in ZRTP encryption. */
zrtp_string32_t cipher_name;
/** \brief SRTP Authentication crypto component name used in ZRTP exchange. */
zrtp_string32_t auth_name;
/** \brief SAS scheme crypto component name used in ZRTP exchange. */
zrtp_string32_t sas_name;
/** \brief Publik Key Exchange name used in ZRTP exchange. */
zrtp_string32_t pk_name;
};
/* \} */
/*======================================================================*/
/* libzrtp Public API: Streams management */
/*======================================================================*/
#if defined(__cplusplus)
extern "C"
{
#endif
/**
* \defgroup zrtp_main_init Initalization and Configuration
* \ingroup zrtp_api
* \{
*/
/**
* \brief Initializes libzrtp global config
*
* zrtp_config_defaults() prepares all fields of zrtp_config_t for further usage in zrtp_init().
* This function allocates all necessary resources and initialize zrtp_config_t#cb with default
* implementations.
*
* \param config - libzrtp config for initialization.
* \warning this function must be used before start operating with the config.
*/
void zrtp_config_defaults(zrtp_config_t* config);
/**
* \brief Initializing libzrtp
*
* This function initializes the library and all its components. zrtp_init() initialize global data
* for all sessions and streams. Fields of the global zrtp context are initialized automatically and
* shouldn't be modified. For correct memory management, global context should be released by
* calling zrtp_down().
*
* \param config - libzrtp inital parameters
* \param zrtp - out parameter, pointer to allocated zrtp global context structure;
* \warning this function \b must be called before any operation with libzrtp.
* \return
* - zrtp_status_ok in successfully initialized or one of zrtp status errors in other case.
* \sa zrtp_down()
*/
zrtp_status_t zrtp_init(zrtp_config_t* config, zrtp_global_t** zrtp);
/*!
* \brief Shutting down the library
*
* Frees all allocated structures and resources. This function \b must be called at the end of use
* to stop libzrtp correctly. zrtp_down() doesn't stop in-progress ZRTP streams. To avoid mistakes,
* close all sessions before library deinitialization.
*
* \param zrtp - global ZRTP context previously allocated by zrtp_init();
* \return
* - zrtp_status_ok if successfully shut down;
* - zrtp_status_fail if an error occurred.
* \sa zrtp_init()
*/
zrtp_status_t zrtp_down(zrtp_global_t* zrtp);
/* \} */
/**
* \defgroup zrtp_main_management ZRTP Connections
* \ingroup zrtp_api
* \{
*/
/**
* \brief ZRTP Session Initialization.
*
* This function allocates and initializes the internal session context data. The given context is
* associated with the specified ZRTP identifier. Only after initialization does the session contain
* ZRTP_MAX_STREAMS_PER_SESSION streams ready to be used.
*
* After successfully initialization, configuration will be done according to the relevant profile
* \c profile. Profile will be applyed to every stream allocated within this session. Before using
* the profile, call zrtp_profile_check() function to make sure that the profile you are applying
* is correct.
*
* \warning Don't call zrtp_session_init() in parallel with other operations on this session.
* \param zrtp - global libzrtp context;
* \param profile - the session configuration profile. If value of this parameter is NULL, default
* profile will be used. NULL profile usage is equivalent to calling zrtp_profile_defaults().
* \param zid - ZRTP peer identificator.
* \param is_initiator - identifies if the endpoint was the signaling initiator of the call. Used to
* provide Passive Mode options to the developer. If your application doesn't control signaling
* or you don't want to support Passive Mode features - set this flag to 1. Check \ref XXX for
* more information.
* \param session - allocated session structure.
* \return
* - zrtp_status_ok if initialization is successful;
* - zrtp_status_fail if an error occurs.
* \sa zrtp_session_down()
*/
zrtp_status_t zrtp_session_init( zrtp_global_t* zrtp,
zrtp_profile_t* profile,
zrtp_zid_t zid,
uint8_t is_initiator,
zrtp_session_t **session);
/**
* \brief ZRTP Session context deinitialization
*
* This function releases all resources allocated for internal context operations by zrtp_init().
*
* \warning Don't call zrtp_session_init() in parallel with other operations on this session.
* \param session - session for deinitialization.
* \sa zrtp_session_init()
*/
void zrtp_session_down(zrtp_session_t *session);
/**
* \brief Obtain information about ZRTP session
*
* Function initialize and fills all fields of zrtp_session_info_t structure accordint to
* current state of ZRTP session.
*
* \param session - zrtp session which parameters should be extracted;
* \param info - out structure to be initialized.
* \return
* - zrtp_status_ok in case of success.
* - zrtp_status_fail if an error occurs.
*/
zrtp_status_t zrtp_session_get(zrtp_session_t *session, zrtp_session_info_t *info);
/**
* \brief Allow user to associate some data with current zrtp session.
* \param session - zrtp session to attach data to.
* \param udata - pointer to the user-data context.
* \sa zrtp_session_get_userdata()
*/
void zrtp_session_set_userdata(zrtp_session_t *session, void* udata);
/**
* \brief Return user data associated with the zrtp session
* \param session - zrtp session to extract user data.
* \return
* - pointer to the user-data context previously set by zrtp_session_set_userdata().
* - NULL if the user data unavailable.
* \sa zrtp_session_set_userdata()
*/
void* zrtp_session_get_userdata(zrtp_session_t *session);
/**
* \brief Attaching a new stream to the session
*
* This function call initializes a ZRTP stream and prepares it for use within the specified
* session. The maximum number of streams for one session is defined by the
* ZRTP_MAX_STREAMS_PER_SESSION variable. All newly created streams are equivalent and have
* ZRTP_STREAM_MODE_CLEAR mode and ZRTP_ACTIVE state. Only after attaching a stream, ZRTP protocol
* can be initiated.
*
* \param session - the ZRTP session within which a new stream is to be
* \param stream - out parameter, attached stream will be stored there
* \return
* - zrtp_status_ok if stream was attached successfully
* - one of zrtp_status_t errors in case of failure
* \sa zrtp_stream_start() zrtp_stream_stop()
*/
zrtp_status_t zrtp_stream_attach(zrtp_session_t *session, zrtp_stream_t** stream);
/**
* \brief Starting a ZRTP stream
*
* ZRTP stream setup is initiated by calling this function. Exchange of command packets begins
* immediately according to protocol. If the option "autosecure" is on, calling this function is the
* only requirement for setting up the ZRTP connection within a stream. If "autosecure" mode is not
* available, calling this function activates only connection within a ZRTP stream. A connection can
* be established manually later by calling zrtp_stream_secure().
*
* Setup of the stream/connection takes a certain interval of time. This function just initiates
* this process. The system of callbacks informs the user about the progress of libzrtp protocol.
*
* \param stream - ZRTP stream to be started.
* \param ssrc - ssrc which will be used in ZRTP protocol messages. It should match with ssrc of
* appropriate RTP stream which will be encrypted by this ZRTP stream.
* \return
* - zrtp_status_ok in case of success;
* - one of zrtp_status_t errors in case of failure
* \sa
* - \ref XXX_GUIDE_CB \ref XXX_GUIDE_MANAGEMENT
* - zrtp_stream_stop() zrtp_stream_secure() zrtp_stream_clear()
*/
zrtp_status_t zrtp_stream_start(zrtp_stream_t* stream, uint32_t ssrc);
/**
* \brief ZRTP protocol stopping
*
* This function stops all protocol operations for the specified stream, releases resources
* allocated on the zrtp_stream_start() and prepares the stream structure for the next use.
*
* This function will stop the protocol at any stage: all delayed tasks are canceled, and the
* protocol packet exchange and encryption is stopped. After this function call it is necessary to
* stop processing traffic using the zrtp_process_xxx() function.
*
* \param stream - the stream being shutdown.
* \return
* - zrtp_status_ok in case of success;
* - one of zrtp_status_t errors in case of failure
* \sa
* - \ref XXX_GUIDE_CB \ref XXX_GUIDE_MANAGEMENT
* - zrtp_stream_start() zrtp_stream_secure() zrtp_stream_clear()
*/
zrtp_status_t zrtp_stream_stop(zrtp_stream_t* stream);
/*!
* \brief Initiating an interruption of the secure connection
*
* This function initiates the shutting down of the ZRTP connection within a stream. In other words,
* after successfully switching to secure mode (\ref XXX SECURE state, fig. 1.5), calling this
* function begins the exchange of packets switching back to insecure (CLEAR) mode.
*
* This function can only be implemented from the SECURE state. Attempt to call this function from
* any other state will end in failure. The client application is informed about protocol
* progress through a system of callbacks.
*
* \param stream - ZRTP stream .
* \return
* - zrtp_status_ok - if shutting down the connection is started successfully.
* - zrtp_status_fail - if shutting down the connection is initiated from an incorrect state.
* \sa
* - \ref XXX_GUIDE_CB \ref XXX_GUIDE_MANAGEMENT
* - zrtp_stream_start() zrtp_stream_secure() zrtp_stream_clear()
*/
zrtp_status_t zrtp_stream_clear(zrtp_stream_t *stream);
/**
* \brief Initiating a secure connection setup
*
* The function initiates a ZRTP connection setup within a stream. In other words, after the
* protocol has started and Discovery phase have been successfully accomplished, calling this
* function will begin the exchange of packets for switching to SECURE mode.
*
* This function can be successfully performed only from the CLEAR state (\ref XXX Figure 1.6).
* Attempting to call this function from any other state will result in failure. The client
* application is informed about protocol progress through a system of callbacks.
*
* \param stream - ZRTP stream to be secured.
* \return
* - zrtp_status_ok - if switching to secure mode started successfully.
* - zrtp_status_fail - if switching to secure mode is initiated from a state other than CLEAR.
* \sa
* - \ref XXX_GUIDE_CB \ref XXX_GUIDE_MANAGEMENT.
* - zrtp_stream_start() zrtp_stream_clear().
*/
zrtp_status_t zrtp_stream_secure(zrtp_stream_t *stream);
/**
* \brief Obtain information about zrtp stream
*
* Function initialize and fills all fields of zrtp_stream_info_t structure accordint to
* current state of zrtp stream.
*
* \param stream - zrtp stream which parameters should be extracted
* \param info - out structure to be initialized
* \return
* - zrtp_status_ok in case of success.
* - zrtp_status_fail if an error occurs.
*/
zrtp_status_t zrtp_stream_get(zrtp_stream_t *stream, zrtp_stream_info_t *info);
/**
* @brief Allow user to associate some data with zrtp stream.
* @param stream - zrtp stream to attach data to.
* @param udata - pointer to the user-data context.
* @sa zrtp_stream_get_userdata()
*/
void zrtp_stream_set_userdata(zrtp_stream_t *stream, void* udata);
/**
* \brief Return user data associated with the zrtp stream
* \return
* - pointer to the user-data context previously set by zrtp_stream_set_userdata()
* - NULL if user data unavailable;
* \sa zrtp_stream_set_userdata()
*/
void* zrtp_stream_get_userdata(const zrtp_stream_t *stream);
/* \} */
/*======================================================================*/
/* libzrtp Public API: Encryption */
/*======================================================================*/
/**
* \defgroup zrtp_main_proto Traffic Processing
* \ingroup zrtp_api
* \{
*/
/**
* \brief Processing outgoing RTP packets
*
* This is the main function for processing outgoing RTP packets. As soon as the protocol is
* started, each outgoing RTP packet (not encrypted) has to go through this function.
*
* It performs different actions depending on the connection state and packet type:
* - In setup ZRTP connection mode, it encrypts outgoing RTP packets. The packet is encrypted right
* in the transferred buffer;
* - Protects codec and data privacy by deleting certain packets from the stream. In this case the
* body and the length of the packet remain unchanged.
*
* \param stream - ZRTP stream to process RTP packet;
* \param packet - buffer storing the RTP packet for encryption. After processing, the encrypted
* packet is stored in the same buffer.
* \param length - the length of the buffered packet. After processing, the length of encrypted
* packet is stored here.
* \warning During encryption, the data length increases in comparison to the source data. Because
* the function uses the same buffer both for incoming and resulting values, the length of the
* buffer must be larger than size of source packet.
* \return
* - zrtp_status_ok if encryption is successful. The packet should be sent to the recipient.
* - zrtp_status_fail if there was an error during encryption. The packet should be rejected.
* - zrtp_status_drop if there was interference in the VoIP client codec protection mechanism. The
* packet should be rejected.
* \sa zrtp_process_srtp() zrtp_process_rtcp() zrtp_process_srtcp()
*/
zrtp_status_t zrtp_process_rtp( zrtp_stream_t *stream,
char* packet,
unsigned int* length);
/**
* \brief Processing incoming RTP packets
*
* This is the main function for incoming RTP packets processing. It is an analogue of
* zrtp_process_rtp() but for an incoming stream. After the protocol is started, each (encrypted)
* incoming RTP packet has to go through this function.
*
* It performs different actions depending on the connection state and packet type:
* - during setup/interruption of ZRTP connection, processes incoming protocol packets. The body
* and length of the packet remain unchanged;
* - in setup ZRTP connection mode, decrypts incoming RTP packet. The packet is decrypted right in
* the transferred buffer;
* - protects codec and data privacy by deleting certain packets from the stream. In this case the
* body and the length of the packet remain unchanged.
*
* \param stream - ZRTP stream for processing
* \param packet - buffer storing the packet for decrypting. After processing, the decrypted packet
* is stored in the same buffer;
* \param length - the length of the buffered packet. After processing, the length of decrypted
* packet is stored here;
* \return
* - zrtp_status_ok if decrypting is successful. Such a packet should be sent to the recipient;
* - zrtp_status_fail if an error occurred during decrypting or command packet processing. The
* packet should be rejected;
* - zrtp_status_drop if the command packet processing is successful or if there was interference
* in the VoIP client codec protection mechanism. The packet should be rejected in either case;
* \sa zrtp_process_rtp() zrtp_process_rtcp() zrtp_process_srtcp()
*/
zrtp_status_t zrtp_process_srtp( zrtp_stream_t *stream,
char* packet,
unsigned int* length);
/*!
* \brief Processing outgoing RTCP packets
*
* This is the main function for processing outgoing RTCP packets. The function behavior is similar
* to that of zrtp_process_rtp():
* - In SECURE mode, encrypts outgoing RTCP packets. The packet is encrypted right in the
* transferred buffer. The length of encrypted packet is returned in the \c length variable;
* - protects codec and data privacy by deleting certain packets from the stream. In this case the
* body and the length of the packet remain unchanged.
*
* \param stream - ZRTP session for processing;
* \param packet - buffer storing RTCP packet;
* \param length - length of the buffered packet.
* \return
* - zrtp_status_ok if encryption is successful. The packet should be sent to the recipient.
* - zrtp_status_fail if there was an error during encryption. The packet should be rejected.
* - zrtp_status_drop if there was interference in the VoIP client codec protection mechanism. The
* packet should be rejected.
* \sa zrtp_process_srtp() zrtp_process_rtp() zrtp_process_srtcp()
*/
zrtp_status_t zrtp_process_rtcp( zrtp_stream_t *stream,
char* packet,
unsigned int* length);
/**
* \brief Processing incoming RTCP packets
*
* This is the main function for processing incoming RTCP packets. The function behavior is similar
* to that of zrtp_process_srtp():
* - In SECURE mode, decrypts incoming RTCP packets. The packet is decrypted right in the
* transferred buffer. The length of the encrypted packet is returned in the \c length variable;
* - In transition states, drops all incoming RTCP traffic. In this case the body and the length of
* the packet remain unchanged.
*
* \param stream - ZRTP stream for processing;
* \param packet - buffer storing the RTCP packet;
* \param length - length of the buffered packet.
* \return
* - zrtp_status_ok if decrypting is successful. Such a packet should be sent to the recipient;
* - zrtp_status_drop if the command packet processing is successful or if there was interference
* in the VoIP client codec protection mechanism. The packet should be rejected in either case;
* - zrtp_status_fail if there was an error during encryption. The packet should be rejected.
* \sa zrtp_process_srtp() zrtp_process_rtp() zrtp_process_rtcp()
*/
zrtp_status_t zrtp_process_srtcp( zrtp_stream_t *stream,
char* packet,
unsigned int* length);
/* \} */
/**
* \defgroup zrtp_main_utils Utilites
* \ingroup zrtp_api
* \{
*/
/**
* \brief Specifies the hash of the peer Hello message for verification.
*
* In accordance with the ZRTP RFC sec. 9, this protocol can prevent DOS attacks by verification of
* the Hello message hash sent through the signaling protocol.
*
* This function allows the user to specify the Hello hash for verification. If after the
* discovering phase the Hello hashes don't match, libzrtp raises the
* zrtp_event_t#ZRTP_EVENT_WRONG_SIGNALING_HASH event. This function should only be called before
* starting the protocol from the ZRTP_STATE_ACTIVE state.
*
* \param stream - stream for operating with;
* \param hash_buff - signaling hash buffer. Function accpt string, not a binary value!;
* \param hash_buff_length - signaling hash length in bytes (must be 64 bytes);
* \return:
* - zrtp_status_ok if the operation finished successfully
* - one of the errors otherwise
* \sa
* - ZRTP RFC. sec 8;
* - zrtp_signaling_hash_get()
*/
zrtp_status_t zrtp_signaling_hash_set( zrtp_stream_t* stream,
const char *hash_buff,
uint32_t hash_buff_length);
/**
* \brief Returns the hash of the Hello message to be transferred in signaling.
*
* To prevent DOS attacks, the hash of the Hello message may be sent through signaling.
* zrtp_signaling_hash_get() may be called after attaching the stream to receive the value of this
* hash.
*
* \param stream - stream for operating with
* \param hash_buff - buffer for storing signaling hash. Function returns already parsed hex string.
* String is null-terminated.
* \param hash_buff_length - buffer length in bytes (not shorter than 65 bytes)
* \return:
* - zrtp_status_ok if the operation finished successfully
* - one of the errors otherwise
* \sa
* - ZRTP RFC. sec 8;
* - zrtp_signaling_hash_set()
*/
zrtp_status_t zrtp_signaling_hash_get( zrtp_stream_t* stream,
char* hash_buff,
uint32_t hash_buff_length);
/**
* \brief Changing the value of the secret's verification flag
*
* This function is used to change (set, unset) the secret's verification flag. zrtp_verified_set()
* changes the relevant internal data and stores a flag in the cache.
* \note
* Special synchronization mechanisms are provided to protect the cache from race conditions. Don't
* change the verified flag directly in the cache - use this function.
*
* \param zrtp - zrtp global data;
* \param zid1 - ZID of the first party;
* \param zid2 - ZID of the second party;
* \param verified - Boolean value of the verified flag.
* \return
* - zrtp_status_ok - if successful;
* - one of zrtp_status_t errors if fails.
*/
zrtp_status_t zrtp_verified_set( zrtp_global_t *zrtp,
zrtp_string16_t *zid1,
zrtp_string16_t *zid2,
uint8_t verified);
/**
* \brief Verifying the ZRTP profile
*
* zrtp_profile_check() checks the correctness of the values in the profile. The following checks
* are performed:
* - the number of components in each group does not exceed ZRTP_MAX_COMP_COUNT;
* - the components declared are supported by the library kernel.
* - presence of the set of obligatory components defined by ZRTP RFC.
*
* \param profile - ZRTP profile for validation;
* \param zrtp - global ZRTP context.
* \return
* - zrtp_status_ok - if profile passed all available tests;
* - one of ZRTP errors - if there are mistakes in the profile. See debug logging for additional
* information.
*/
zrtp_status_t zrtp_profile_check(const zrtp_profile_t* profile, zrtp_global_t* zrtp);
/**
* \brief Configure the default ZRTP profile
*
* These options are used:
* \code
* "active" is enabled;
* "allowclear" is disabled by default and enabled for Zfone only;
* "autosecure" is enabled;
* "disclose_bit" is disabled;
* cache_ttl = ZRTP_CACHE_DEFAULT_TTL defined by ZRTP RFC;
*
* [sas_schemes] = ZRTP_SAS_BASE256, ZRTP_SAS_BASE32;
* [cipher_types] = ZRTP_CIPHER_AES128;
* [pk_schemes] = ZRTP_PKTYPE_DH3072;
* [auth_tag_lens] = ZRTP_ATL_HS32;
* [hash_schemes] = ZRTP_HASH_SHA256;
* \endcode
*
* \param profile - ZRTP stream profile for filling;
* \param zrtp - libzrtp global context.
*/
void zrtp_profile_defaults(zrtp_profile_t* profile, zrtp_global_t* zrtp);
/**
* \brief Search for a component in the profile by ID
*
* The utility function returning the position of an element of the specified type in the profile.
* Used by libZRTP kernel and for external use.
*
* \param profile - ZRTP profile;
* \param type - sought component type;
* \param id - sought component ID.
* \return
* - component position - if component was found;
* -1 - if the component with the specified ID can't be found in profile.
*/
int zrtp_profile_find(const zrtp_profile_t* profile, zrtp_crypto_comp_t type, uint8_t id);
/* \} */
/**
* \defgroup zrtp_main_rng Random Number Generation
* \ingroup zrtp_api
* \{
* The generation of cryptographic key material is a highly sensitive process. To do this, you need
* high entropy random numbers that an attacker cannot predict. This section \ref rng gives basic
* knowliges andbot the RNG and it's implementation in libzrtp.
* \warning
* \ref rng \c MUST be read by every developer using libzrtp.
*/
/**
* \brief Entropy accumulation routine
*
* The random number generation scheme is described in detail in chapter \ref XXX. This function
* gets \c length bytes of entropy from \c buffer and hashes it into the special storage. This
* function should be called periodically from the user's space to increase entropy quality.
* \warning
* RNG is a very important and sensitive component of the crypto-system. Please, pay attention to
* \ref rng.
* \param zrtp - libzrtp global context;
* \param buffer - pointer to the buffer with entropy for accumulating;
* \param length - entropy size in bytes.
* \return: number of hashed bytes.
*/
int zrtp_entropy_add(zrtp_global_t* zrtp, const unsigned char *buffer, uint32_t length);
/**
* \brief Random string generation
*
* zrtp_randstr() generates \c length bytes of "random" data. We say "random" because the
* "randomness" of the generated sequence depends on the quality of the entropy passed to
* zrtp_entropy_add(). If the user provides "good" entropy, zrtp_randstr() generates sufficiently
* "random" data.
*
* \param zrtp - libzrtp global context;
* \param buffer - buffer into which random data will be generated;
* \param length - length of required sequence in bytes.
* \return
* - length of generated sequence in bytes or -1 in case of error
* \sa \ref rng
*/
int zrtp_randstr(zrtp_global_t* zrtp, unsigned char *buffer, uint32_t length);
/* \} */
#if defined(__cplusplus)
}
#endif
#endif /* __ZRTP_H__ */
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