rtp.h

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/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C) 1999 - 2006, Digium, Inc.
 *
 * Mark Spencer <markster@digium.com>
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 * This program is free software, distributed under the terms of
 * the GNU General Public License Version 2. See the LICENSE file
 * at the top of the source tree.
 */

/*!
 * \file rtp.h
 * \brief Supports RTP and RTCP with Symmetric RTP support for NAT traversal.
 *
 * RTP is defined in RFC 3550.
 */

#ifndef _ASTERISK_RTP_H
#define _ASTERISK_RTP_H

#include "asterisk/network.h"

#include "asterisk/frame.h"
#include "asterisk/io.h"
#include "asterisk/sched.h"
#include "asterisk/channel.h"
#include "asterisk/linkedlists.h"

#if defined(__cplusplus) || defined(c_plusplus)
extern "C" {
#endif

/* Codes for RTP-specific data - not defined by our AST_FORMAT codes */
/*! DTMF (RFC2833) */
#define AST_RTP_DTMF             (1 << 0)
/*! 'Comfort Noise' (RFC3389) */
#define AST_RTP_CN               (1 << 1)
/*! DTMF (Cisco Proprietary) */
#define AST_RTP_CISCO_DTMF       (1 << 2)
/*! Maximum RTP-specific code */
#define AST_RTP_MAX              AST_RTP_CISCO_DTMF

/*! Maxmum number of payload defintions for a RTP session */
#define MAX_RTP_PT         256

/*! T.140 Redundancy Maxium number of generations */
#define RED_MAX_GENERATION 5

#define FLAG_3389_WARNING     (1 << 0)

enum ast_rtp_options {
   AST_RTP_OPT_G726_NONSTANDARD = (1 << 0),
};

enum ast_rtp_get_result {
   /*! Failed to find the RTP structure */
   AST_RTP_GET_FAILED = 0,
   /*! RTP structure exists but true native bridge can not occur so try partial */
   AST_RTP_TRY_PARTIAL,
   /*! RTP structure exists and native bridge can occur */
   AST_RTP_TRY_NATIVE,
};

/*! \brief Variables used in ast_rtcp_get function */
enum ast_rtp_qos_vars {
   AST_RTP_TXCOUNT,
   AST_RTP_RXCOUNT,
   AST_RTP_TXJITTER,
   AST_RTP_RXJITTER,
   AST_RTP_RXPLOSS,
   AST_RTP_TXPLOSS,
   AST_RTP_RTT
};

struct ast_rtp;
/*! T.140 Redundancy structure*/
struct rtp_red;

/*! \brief The value of each payload format mapping: */
struct rtpPayloadType {
   int isAstFormat;     /*!< whether the following code is an AST_FORMAT */
   int code;
};

/*! \brief This is the structure that binds a channel (SIP/Jingle/H.323) to the RTP subsystem 
*/
struct ast_rtp_protocol {
   /*! Get RTP struct, or NULL if unwilling to transfer */
   enum ast_rtp_get_result (* const get_rtp_info)(struct ast_channel *chan, struct ast_rtp **rtp);
   /*! Get RTP struct, or NULL if unwilling to transfer */
   enum ast_rtp_get_result (* const get_vrtp_info)(struct ast_channel *chan, struct ast_rtp **rtp);
   /*! Get RTP struct, or NULL if unwilling to transfer */
   enum ast_rtp_get_result (* const get_trtp_info)(struct ast_channel *chan, struct ast_rtp **rtp);
   /*! Set RTP peer */
   int (* const set_rtp_peer)(struct ast_channel *chan, struct ast_rtp *peer, struct ast_rtp *vpeer, struct ast_rtp *tpeer, int codecs, int nat_active);
   int (* const get_codec)(struct ast_channel *chan);
   const char * const type;
   AST_LIST_ENTRY(ast_rtp_protocol) list;
};

enum ast_rtp_quality_type {
   RTPQOS_SUMMARY = 0,
   RTPQOS_JITTER,
   RTPQOS_LOSS,
   RTPQOS_RTT
};

/*! \brief RTCP quality report storage */
struct ast_rtp_quality {
   unsigned int local_ssrc;          /*!< Our SSRC */
   unsigned int local_lostpackets;   /*!< Our lost packets */
   double       local_jitter;        /*!< Our calculated jitter */
   unsigned int local_count;         /*!< Number of received packets */
   unsigned int remote_ssrc;         /*!< Their SSRC */
   unsigned int remote_lostpackets;  /*!< Their lost packets */
   double       remote_jitter;       /*!< Their reported jitter */
   unsigned int remote_count;        /*!< Number of transmitted packets */
   double       rtt;                 /*!< Round trip time */
};

/*! RTP callback structure */
typedef int (*ast_rtp_callback)(struct ast_rtp *rtp, struct ast_frame *f, void *data);

/*!
 * \brief Get the amount of space required to hold an RTP session
 * \return number of bytes required
 */
size_t ast_rtp_alloc_size(void);

/*!
 * \brief Initializate a RTP session.
 *
 * \param sched
 * \param io
 * \param rtcpenable
 * \param callbackmode
 * \return A representation (structure) of an RTP session.
 */
struct ast_rtp *ast_rtp_new(struct sched_context *sched, struct io_context *io, int rtcpenable, int callbackmode);

/*!
 * \brief Initializate a RTP session using an in_addr structure.
 *
 * This fuction gets called by ast_rtp_new().
 *
 * \param sched
 * \param io
 * \param rtcpenable
 * \param callbackmode
 * \param in
 * \return A representation (structure) of an RTP session.
 */
struct ast_rtp *ast_rtp_new_with_bindaddr(struct sched_context *sched, struct io_context *io, int rtcpenable, int callbackmode, struct in_addr in);

void ast_rtp_set_peer(struct ast_rtp *rtp, struct sockaddr_in *them);

/*! 
 * \since 1.4.26
 * \brief set potential alternate source for RTP media
 *
 * This function may be used to give the RTP stack a hint that there is a potential
 * second source of media. One case where this is used is when the SIP stack receives
 * a REINVITE to which it will be replying with a 491. In such a scenario, the IP and
 * port information in the SDP of that REINVITE lets us know that we may receive media
 * from that source/those sources even though the SIP transaction was unable to be completed
 * successfully
 *
 * \param rtp The RTP structure we wish to set up an alternate host/port on
 * \param alt The address information for the alternate media source
 * \retval void
 */
void ast_rtp_set_alt_peer(struct ast_rtp *rtp, struct sockaddr_in *alt);

/* Copies from rtp to them and returns 1 if there was a change or 0 if it was already the same */
int ast_rtp_get_peer(struct ast_rtp *rtp, struct sockaddr_in *them);

void ast_rtp_get_us(struct ast_rtp *rtp, struct sockaddr_in *us);

struct ast_rtp *ast_rtp_get_bridged(struct ast_rtp *rtp);

/*! Destroy RTP session */
void ast_rtp_destroy(struct ast_rtp *rtp);

void ast_rtp_reset(struct ast_rtp *rtp);

/*! Stop RTP session, do not destroy structure */
void ast_rtp_stop(struct ast_rtp *rtp);

void ast_rtp_set_callback(struct ast_rtp *rtp, ast_rtp_callback callback);

void ast_rtp_set_data(struct ast_rtp *rtp, void *data);

int ast_rtp_write(struct ast_rtp *rtp, struct ast_frame *f);

struct ast_frame *ast_rtp_read(struct ast_rtp *rtp);

struct ast_frame *ast_rtcp_read(struct ast_rtp *rtp);

int ast_rtp_fd(struct ast_rtp *rtp);

int ast_rtcp_fd(struct ast_rtp *rtp);

int ast_rtp_senddigit_begin(struct ast_rtp *rtp, char digit);

int ast_rtp_senddigit_end(struct ast_rtp *rtp, char digit);

int ast_rtp_sendcng(struct ast_rtp *rtp, int level);

int ast_rtp_setqos(struct ast_rtp *rtp, int tos, int cos, char *desc);

/*! \brief When changing sources, don't generate a new SSRC */
void ast_rtp_set_constantssrc(struct ast_rtp *rtp);

void ast_rtp_new_source(struct ast_rtp *rtp);

/*! \brief  Setting RTP payload types from lines in a SDP description: */
void ast_rtp_pt_clear(struct ast_rtp* rtp);
/*! \brief Set payload types to defaults */
void ast_rtp_pt_default(struct ast_rtp* rtp);

/*! \brief Copy payload types between RTP structures */
void ast_rtp_pt_copy(struct ast_rtp *dest, struct ast_rtp *src);

/*! \brief Activate payload type */
void ast_rtp_set_m_type(struct ast_rtp* rtp, int pt);

/*! \brief clear payload type */
void ast_rtp_unset_m_type(struct ast_rtp* rtp, int pt);

/*! \brief Set payload type to a known MIME media type for a codec
 *
 * \param rtp RTP structure to modify
 * \param pt Payload type entry to modify
 * \param mimeType top-level MIME type of media stream (typically "audio", "video", "text", etc.)
 * \param mimeSubtype MIME subtype of media stream (typically a codec name)
 * \param options Zero or more flags from the ast_rtp_options enum
 *
 * This function 'fills in' an entry in the list of possible formats for
 * a media stream associated with an RTP structure.
 *
 * \retval 0 on success
 * \retval -1 if the payload type is out of range
 * \retval -2 if the mimeType/mimeSubtype combination was not found
 */
int ast_rtp_set_rtpmap_type(struct ast_rtp* rtp, int pt,
              char *mimeType, char *mimeSubtype,
              enum ast_rtp_options options);

/*! \brief Set payload type to a known MIME media type for a codec with a specific sample rate
 *
 * \param rtp RTP structure to modify
 * \param pt Payload type entry to modify
 * \param mimeType top-level MIME type of media stream (typically "audio", "video", "text", etc.)
 * \param mimeSubtype MIME subtype of media stream (typically a codec name)
 * \param options Zero or more flags from the ast_rtp_options enum
 * \param sample_rate The sample rate of the media stream
 *
 * This function 'fills in' an entry in the list of possible formats for
 * a media stream associated with an RTP structure.
 *
 * \retval 0 on success
 * \retval -1 if the payload type is out of range
 * \retval -2 if the mimeType/mimeSubtype combination was not found
 */
int ast_rtp_set_rtpmap_type_rate(struct ast_rtp* rtp, int pt,
             char *mimeType, char *mimeSubtype,
             enum ast_rtp_options options,
             unsigned int sample_rate);

/*! \brief  Mapping between RTP payload format codes and Asterisk codes: */
struct rtpPayloadType ast_rtp_lookup_pt(struct ast_rtp* rtp, int pt);
int ast_rtp_lookup_code(struct ast_rtp* rtp, int isAstFormat, int code);

void ast_rtp_get_current_formats(struct ast_rtp* rtp,
             int* astFormats, int* nonAstFormats);

/*! \brief  Mapping an Asterisk code into a MIME subtype (string): */
const char *ast_rtp_lookup_mime_subtype(int isAstFormat, int code,
               enum ast_rtp_options options);

/*! \brief Get the sample rate associated with known RTP payload types
 *
 * \param isAstFormat True if the value in the 'code' parameter is an AST_FORMAT value
 * \param code Format code, either from AST_FORMAT list or from AST_RTP list
 *
 * \return the sample rate if the format was found, zero if it was not found
 */
unsigned int ast_rtp_lookup_sample_rate(int isAstFormat, int code);

/*! \brief Build a string of MIME subtype names from a capability list */
char *ast_rtp_lookup_mime_multiple(char *buf, size_t size, const int capability,
               const int isAstFormat, enum ast_rtp_options options);

void ast_rtp_setnat(struct ast_rtp *rtp, int nat);

int ast_rtp_getnat(struct ast_rtp *rtp);

/*! \brief Indicate whether this RTP session is carrying DTMF or not */
void ast_rtp_setdtmf(struct ast_rtp *rtp, int dtmf);

/*! \brief Compensate for devices that send RFC2833 packets all at once */
void ast_rtp_setdtmfcompensate(struct ast_rtp *rtp, int compensate);

/*! \brief Enable STUN capability */
void ast_rtp_setstun(struct ast_rtp *rtp, int stun_enable);

/*! \brief Generic STUN request
 * send a generic stun request to the server specified.
 * \param s the socket used to send the request
 * \param dst the address of the STUN server
 * \param username if non null, add the username in the request
 * \param answer if non null, the function waits for a response and
 *    puts here the externally visible address.
 * \return 0 on success, other values on error.
 * The interface it may change in the future.
 */
int ast_stun_request(int s, struct sockaddr_in *dst,
   const char *username, struct sockaddr_in *answer);

/*! \brief Send STUN request for an RTP socket
 * Deprecated, this is just a wrapper for ast_rtp_stun_request()
 */
void ast_rtp_stun_request(struct ast_rtp *rtp, struct sockaddr_in *suggestion, const char *username);

/*! \brief The RTP bridge.
   \arg \ref AstRTPbridge
*/
int ast_rtp_bridge(struct ast_channel *c0, struct ast_channel *c1, int flags, struct ast_frame **fo, struct ast_channel **rc, int timeoutms);

/*! \brief Register an RTP channel client */
int ast_rtp_proto_register(struct ast_rtp_protocol *proto);

/*! \brief Unregister an RTP channel client */
void ast_rtp_proto_unregister(struct ast_rtp_protocol *proto);

int ast_rtp_make_compatible(struct ast_channel *dest, struct ast_channel *src, int media);

/*! \brief If possible, create an early bridge directly between the devices without
           having to send a re-invite later */
int ast_rtp_early_bridge(struct ast_channel *c0, struct ast_channel *c1);

/*! \brief Get QOS stats on a RTP channel
 * \since 1.6.1
 */
int ast_rtp_get_qos(struct ast_rtp *rtp, const char *qos, char *buf, unsigned int buflen);

/*! \brief Return RTP and RTCP QoS values
 * \since 1.6.1
 */
unsigned int ast_rtp_get_qosvalue(struct ast_rtp *rtp, enum ast_rtp_qos_vars value);

/*! \brief Set RTPAUDIOQOS(...) variables on a channel when it is being hung up
 * \since 1.6.1
 */
void ast_rtp_set_vars(struct ast_channel *chan, struct ast_rtp *rtp);

/*! \brief Return RTCP quality string 
 *
 *  \param rtp An rtp structure to get qos information about.
 *
 *  \param qual An (optional) rtp quality structure that will be 
 *              filled with the quality information described in 
 *              the ast_rtp_quality structure. This structure is
 *              not dependent on any qtype, so a call for any
 *              type of information would yield the same results
 *              because ast_rtp_quality is not a data type 
 *              specific to any qos type.
 *
 *  \param qtype The quality type you'd like, default should be
 *               RTPQOS_SUMMARY which returns basic information
 *               about the call. The return from RTPQOS_SUMMARY
 *               is basically ast_rtp_quality in a string. The
 *               other types are RTPQOS_JITTER, RTPQOS_LOSS and
 *               RTPQOS_RTT which will return more specific 
 *               statistics.
 * \version 1.6.1 added qtype parameter
 */
char *ast_rtp_get_quality(struct ast_rtp *rtp, struct ast_rtp_quality *qual, enum ast_rtp_quality_type qtype);
/*! \brief Send an H.261 fast update request. Some devices need this rather than the XML message  in SIP */
int ast_rtcp_send_h261fur(void *data);

void ast_rtp_init(void);                                      /*! Initialize RTP subsystem */
int ast_rtp_reload(void);                                     /*! reload rtp configuration */
void ast_rtp_new_init(struct ast_rtp *rtp);

/*! \brief Set codec preference */
void ast_rtp_codec_setpref(struct ast_rtp *rtp, struct ast_codec_pref *prefs);

/*! \brief Get codec preference */
struct ast_codec_pref *ast_rtp_codec_getpref(struct ast_rtp *rtp);

/*! \brief get format from predefined dynamic payload format */
int ast_rtp_codec_getformat(int pt);

/*! \brief Set rtp timeout */
void ast_rtp_set_rtptimeout(struct ast_rtp *rtp, int timeout);
/*! \brief Set rtp hold timeout */
void ast_rtp_set_rtpholdtimeout(struct ast_rtp *rtp, int timeout);
/*! \brief set RTP keepalive interval */
void ast_rtp_set_rtpkeepalive(struct ast_rtp *rtp, int period);
/*! \brief Get RTP keepalive interval */
int ast_rtp_get_rtpkeepalive(struct ast_rtp *rtp);
/*! \brief Get rtp hold timeout */
int ast_rtp_get_rtpholdtimeout(struct ast_rtp *rtp);
/*! \brief Get rtp timeout */
int ast_rtp_get_rtptimeout(struct ast_rtp *rtp);
/* \brief Put RTP timeout timers on hold during another transaction, like T.38 */
void ast_rtp_set_rtptimers_onhold(struct ast_rtp *rtp);

/*! \brief Initalize t.140 redudancy 
 * \param ti time between each t140red frame is sent
 * \param red_pt payloadtype for RTP packet
 * \param pt payloadtype numbers for each generation including primary data
 * \param num_gen number of redundant generations, primary data excluded
 * \since 1.6.1
 */
int rtp_red_init(struct ast_rtp *rtp, int ti, int *pt, int num_gen);

/*! \brief Buffer t.140 data */
void red_buffer_t140(struct ast_rtp *rtp, struct ast_frame *f);



#if defined(__cplusplus) || defined(c_plusplus)
}
#endif

#endif /* _ASTERISK_RTP_H */