rtcp.c File Reference

RTCP processing. More...

#include <math.h>
#include <stdlib.h>
#include <sys/time.h>
#include "debug.h"
#include "rtp.h"
#include "rtcp.h"
#include "utils.h"

Include dependency graph for rtcp.c:

Macros
#define	LINK_QUALITY_FILTER_K   3.0

Typedefs
typedef enum janus_rtp_packet_status	janus_rtp_packet_status

Enumerations
enum	janus_rtp_packet_status { janus_rtp_packet_status_notreceived = 0 , janus_rtp_packet_status_smalldelta = 1 , janus_rtp_packet_status_largeornegativedelta = 2 , janus_rtp_packet_status_reserved = 3 }

Functions
gboolean	janus_is_rtcp (char *buf, guint len)
	Helper method to demultiplex RTCP from other protocols.
int	janus_rtcp_parse (janus_rtcp_context *ctx, char *packet, int len)
	Method to parse/validate an RTCP message.
guint32	janus_rtcp_get_sender_ssrc (char *packet, int len)
	Method to quickly retrieve the sender SSRC (needed for demuxing RTCP in BUNDLE)
guint32	janus_rtcp_get_receiver_ssrc (char *packet, int len)
	Method to quickly retrieve the received SSRC (needed for demuxing RTCP in BUNDLE)
void	janus_rtcp_swap_report_blocks (char *packet, int len, uint32_t rtx_ssrc)
	Method to swap Report Blocks and move media RB in first position in case rtx SSRC comes first.
gboolean	janus_rtcp_check_len (janus_rtcp_header *rtcp, int len)
	Method to check that a RTCP packet size is at least the minimum necessary (8 bytes) and to validate the length field against the actual size.
gboolean	janus_rtcp_check_sr (janus_rtcp_header *rtcp, int len)
	Method to check if a RTCP packet could contain a Sender Report.
gboolean	janus_rtcp_check_rr (janus_rtcp_header *rtcp, int len)
	Method to check if a RTCP packet could contain a Receiver Report.
gboolean	janus_rtcp_check_fci (janus_rtcp_header *rtcp, int len, int sizeof_fci)
	Method to check if a RTCP packet could contain a Feedback Message with a defined FCI size.
gboolean	janus_rtcp_check_remb (janus_rtcp_header *rtcp, int len)
	Method to check if a RTCP packet could contain an AFB REMB Message.
int	janus_rtcp_fix_ssrc (janus_rtcp_context *ctx, char *packet, int len, int fixssrc, uint32_t newssrcl, uint32_t newssrcr)
	Method to fix an RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)
char *	janus_rtcp_filter (char *packet, int len, int *newlen)
	Method to filter an outgoing RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)
int	janus_rtcp_process_incoming_rtp (janus_rtcp_context *ctx, char *packet, int len, gboolean rfc4588_pkt, gboolean rfc4588_enabled, gboolean retransmissions_disabled, GHashTable *clock_rates)
	Method to quickly process the header of an incoming RTP packet to update the associated RTCP context.
uint32_t	janus_rtcp_context_get_rtt (janus_rtcp_context *ctx)
	Method to retrieve the estimated round-trip time from an existing RTCP context.
uint32_t	janus_rtcp_context_get_in_link_quality (janus_rtcp_context *ctx)
	Method to retrieve inbound link quality from an existing RTCP context.
uint32_t	janus_rtcp_context_get_in_media_link_quality (janus_rtcp_context *ctx)
	Method to retrieve inbound media link quality from an existing RTCP context.
uint32_t	janus_rtcp_context_get_out_link_quality (janus_rtcp_context *ctx)
	Method to retrieve outbound link quality from an existing RTCP context.
uint32_t	janus_rtcp_context_get_out_media_link_quality (janus_rtcp_context *ctx)
	Method to retrieve outbound media link quality from an existing RTCP context.
int32_t	janus_rtcp_context_get_lost_all (janus_rtcp_context *ctx, gboolean remote)
	Method to retrieve the total number of lost packets from an existing RTCP context.
uint32_t	janus_rtcp_context_get_jitter (janus_rtcp_context *ctx, gboolean remote)
	Method to retrieve the jitter from an existing RTCP context.
int	janus_rtcp_report_block (janus_rtcp_context *ctx, janus_report_block *rb)
	Method to fill in a Report Block in a Receiver Report.
int	janus_rtcp_fix_report_data (char *packet, int len, uint32_t base_ts, uint32_t base_ts_prev, uint32_t ssrc_peer, uint32_t ssrc_local, uint32_t ssrc_expected, gboolean video)
	Method to fix incoming RTCP SR and RR data.
gboolean	janus_rtcp_has_bye (char *packet, int len)
	Method to check whether an RTCP message contains a BYE message.
gboolean	janus_rtcp_has_fir (char *packet, int len)
	Method to check whether an RTCP message contains a FIR request.
gboolean	janus_rtcp_has_pli (char *packet, int len)
	Method to check whether an RTCP message contains a PLI request.
GSList *	janus_rtcp_get_nacks (char *packet, int len)
	Method to parse an RTCP NACK message.
int	janus_rtcp_remove_nacks (char *packet, int len)
	Method to remove an RTCP NACK message.
uint32_t	janus_rtcp_get_remb (char *packet, int len)
	Inspect an existing RTCP REMB message to retrieve the reported bitrate.
int	janus_rtcp_cap_remb (char *packet, int len, uint32_t bitrate)
	Method to modify an existing RTCP REMB message to cap the reported bitrate.
int	janus_rtcp_sdes_cname (char *packet, int len, const char *cname, int cnamelen)
	Method to generate a new RTCP SDES message.
int	janus_rtcp_remb (char *packet, int len, uint32_t bitrate)
	Method to generate a new RTCP REMB message to cap the reported bitrate.
int	janus_rtcp_remb_ssrcs (char *packet, int len, uint32_t bitrate, uint8_t numssrc)
	Method to generate a new RTCP REMB message to cap the reported bitrate, but for more SSRCs.
int	janus_rtcp_fir (char *packet, int len, int *seqnr)
	Method to generate a new RTCP FIR message to request a key frame.
int	janus_rtcp_pli (char *packet, int len)
	Method to generate a new RTCP PLI message to request a key frame.
int	janus_rtcp_nacks (char *packet, int len, GSList *nacks)
	Method to generate a new RTCP NACK message to report lost packets.
int	janus_rtcp_transport_wide_cc_feedback (char *packet, size_t size, guint32 ssrc, guint32 media, guint8 feedback_packet_count, GQueue *transport_wide_cc_stats)
	Method to generate a new RTCP transport wide message to report reception stats.

Detailed Description

RTCP processing.

Author

Lorenzo Miniero loren.nosp@m.zo@m.nosp@m.eetec.nosp@m.ho.c.nosp@m.om

Copyright

GNU General Public License v3

Implementation (based on the oRTP structures) of the RTCP messages. RTCP messages coming through the server are parsed and, if needed (according to http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00), fixed before they are sent to the peers (e.g., to fix SSRCs that may have been changed by the server). Methods to generate FIR messages and generate/cap REMB messages are provided as well.

Protocols

Macro Definition Documentation

LINK_QUALITY_FILTER_K

#define LINK_QUALITY_FILTER_K   3.0

Typedef Documentation

janus_rtp_packet_status

typedef enum janus_rtp_packet_status janus_rtp_packet_status

Enumeration Type Documentation

janus_rtp_packet_status

enum janus_rtp_packet_status

Enumerator
janus_rtp_packet_status_notreceived
janus_rtp_packet_status_smalldelta
janus_rtp_packet_status_largeornegativedelta
janus_rtp_packet_status_reserved

Function Documentation

janus_is_rtcp()

gboolean janus_is_rtcp	(	char *	buf,
		guint	len )

Helper method to demultiplex RTCP from other protocols.

Parameters

[in]	buf	Buffer to inspect
[in]	len	Length of the buffer to inspect

janus_rtcp_cap_remb()

int janus_rtcp_cap_remb	(	char *	packet,
		int	len,
		uint32_t	bitrate )

Method to modify an existing RTCP REMB message to cap the reported bitrate.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes
[in]	bitrate	The new bitrate to report (e.g., 128000)

Returns

0 in case of success, -1 on errors

janus_rtcp_check_fci()

gboolean janus_rtcp_check_fci	(	janus_rtcp_header *	rtcp,
		int	len,
		int	sizeof_fci )

Method to check if a RTCP packet could contain a Feedback Message with a defined FCI size.

Parameters

[in]	rtcp	The RTCP message
[in]	len	The message data length in bytes
[in]	sizeof_fci	The size of a FCI entry

Returns

TRUE if packet is OK, or FALSE in case of error

janus_rtcp_check_len()

gboolean janus_rtcp_check_len	(	janus_rtcp_header *	rtcp,
		int	len )

Method to check that a RTCP packet size is at least the minimum necessary (8 bytes) and to validate the length field against the actual size.

Parameters

[in]	rtcp	The RTCP message
[in]	len	The message data length in bytes

Returns

TRUE if packet is OK, or FALSE in case of error

janus_rtcp_check_remb()

gboolean janus_rtcp_check_remb	(	janus_rtcp_header *	rtcp,
		int	len )

Method to check if a RTCP packet could contain an AFB REMB Message.

Parameters

[in]	rtcp	The RTCP message
[in]	len	The message data length in bytes

Returns

TRUE if packet is OK, or FALSE in case of error

janus_rtcp_check_rr()

gboolean janus_rtcp_check_rr	(	janus_rtcp_header *	rtcp,
		int	len )

Method to check if a RTCP packet could contain a Receiver Report.

Parameters

[in]	rtcp	The RTCP message
[in]	len	The message data length in bytes

Returns

TRUE if packet is OK, or FALSE in case of error

janus_rtcp_check_sr()

gboolean janus_rtcp_check_sr	(	janus_rtcp_header *	rtcp,
		int	len )

Method to check if a RTCP packet could contain a Sender Report.

Parameters

[in]	rtcp	The RTCP message
[in]	len	The message data length in bytes

Returns

TRUE if packet is OK, or FALSE in case of error

janus_rtcp_context_get_in_link_quality()

uint32_t janus_rtcp_context_get_in_link_quality

(

janus_rtcp_context *

ctx

)

Method to retrieve inbound link quality from an existing RTCP context.

Parameters

[in]

ctx

The RTCP context to query

Returns

Inbound link quality estimation

janus_rtcp_context_get_in_media_link_quality()

uint32_t janus_rtcp_context_get_in_media_link_quality

(

janus_rtcp_context *

ctx

)

Method to retrieve inbound media link quality from an existing RTCP context.

Parameters

[in]

ctx

The RTCP context to query

Returns

Inbound media link quality estimation

janus_rtcp_context_get_jitter()

uint32_t janus_rtcp_context_get_jitter	(	janus_rtcp_context *	ctx,
		gboolean	remote )

Method to retrieve the jitter from an existing RTCP context.

Parameters

[in]	ctx	The RTCP context to query
[in]	remote	Whether we're querying the remote (provided by peer) or local (computed by Janus) info

Returns

The computed jitter

janus_rtcp_context_get_lost_all()

int32_t janus_rtcp_context_get_lost_all	(	janus_rtcp_context *	ctx,
		gboolean	remote )

Method to retrieve the total number of lost packets from an existing RTCP context.

Parameters

[in]	ctx	The RTCP context to query
[in]	remote	Whether we're querying the remote (provided by peer) or local (computed by Janus) info

Returns

The total number of lost packets

janus_rtcp_context_get_out_link_quality()

uint32_t janus_rtcp_context_get_out_link_quality

(

janus_rtcp_context *

ctx

)

Method to retrieve outbound link quality from an existing RTCP context.

Parameters

[in]

ctx

The RTCP context to query

Returns

Outbound link quality estimation

janus_rtcp_context_get_out_media_link_quality()

uint32_t janus_rtcp_context_get_out_media_link_quality

(

janus_rtcp_context *

ctx

)

Method to retrieve outbound media link quality from an existing RTCP context.

Parameters

[in]

ctx

The RTCP context to query

Returns

Outbound media link quality estimation

janus_rtcp_context_get_rtt()

uint32_t janus_rtcp_context_get_rtt

(

janus_rtcp_context *

ctx

)

Method to retrieve the estimated round-trip time from an existing RTCP context.

Parameters

[in]

ctx

The RTCP context to query

Returns

The estimated round-trip time

janus_rtcp_filter()

char * janus_rtcp_filter	(	char *	packet,
		int	len,
		int *	newlen )

Method to filter an outgoing RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes
[in,out]	newlen	The data length of the filtered RTCP message

Returns

A pointer to the new RTCP message data, NULL in case all messages have been filtered out

janus_rtcp_fir()

int janus_rtcp_fir	(	char *	packet,
		int	len,
		int *	seqnr )

Method to generate a new RTCP FIR message to request a key frame.

Parameters

[in]	packet	The buffer data (MUST be at least 20 chars)
[in]	len	The message data length in bytes (MUST be 20)
[in,out]	seqnr	The current FIR sequence number (will be incremented by the method)

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_fix_report_data()

int janus_rtcp_fix_report_data	(	char *	packet,
		int	len,
		uint32_t	base_ts,
		uint32_t	base_ts_prev,
		uint32_t	ssrc_peer,
		uint32_t	ssrc_local,
		uint32_t	ssrc_expected,
		gboolean	video )

Method to fix incoming RTCP SR and RR data.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes
[in]	base_ts	RTP context base timestamp to compute offset
[in]	base_ts_prev	RTP context base timestamp to compute offset
[in]	ssrc_peer	The remote SSRC in usage for this stream
[in]	ssrc_local	The local SSRC in usage for this stream
[in]	ssrc_expected	The expected SSRC for this RTCP packet
[in]	video	Whether the RTCP packet contains report for video data

Returns

The number of fields updated, negative values on errors

janus_rtcp_fix_ssrc()

int janus_rtcp_fix_ssrc	(	janus_rtcp_context *	ctx,
		char *	packet,
		int	len,
		int	fixssrc,
		uint32_t	newssrcl,
		uint32_t	newssrcr )

Method to fix an RTCP message (http://tools.ietf.org/html/draft-ietf-straw-b2bua-rtcp-00)

Parameters

[in]	ctx	RTCP context to update, if needed (optional)
[in]	packet	The message data
[in]	len	The message data length in bytes
[in]	fixssrc	Whether the method needs to fix the message or just parse it
[in]	newssrcl	The SSRC of the sender to put in the message
[in]	newssrcr	The SSRC of the receiver to put in the message

Returns

0 in case of success, -1 on errors

janus_rtcp_get_nacks()

GSList * janus_rtcp_get_nacks	(	char *	packet,
		int	len )

Method to parse an RTCP NACK message.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

A list of janus_nack elements containing the sequence numbers to send again

janus_rtcp_get_receiver_ssrc()

guint32 janus_rtcp_get_receiver_ssrc	(	char *	packet,
		int	len )

Method to quickly retrieve the received SSRC (needed for demuxing RTCP in BUNDLE)

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

The receiver SSRC, or 0 in case of error

janus_rtcp_get_remb()

uint32_t janus_rtcp_get_remb	(	char *	packet,
		int	len )

Inspect an existing RTCP REMB message to retrieve the reported bitrate.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

The reported bitrate if successful, 0 if no REMB packet was available

janus_rtcp_get_sender_ssrc()

guint32 janus_rtcp_get_sender_ssrc	(	char *	packet,
		int	len )

Method to quickly retrieve the sender SSRC (needed for demuxing RTCP in BUNDLE)

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

The sender SSRC, or 0 in case of error

janus_rtcp_has_bye()

gboolean janus_rtcp_has_bye	(	char *	packet,
		int	len )

Method to check whether an RTCP message contains a BYE message.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

TRUE in case of success, FALSE otherwise

janus_rtcp_has_fir()

gboolean janus_rtcp_has_fir	(	char *	packet,
		int	len )

Method to check whether an RTCP message contains a FIR request.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

TRUE in case of success, FALSE otherwise

janus_rtcp_has_pli()

gboolean janus_rtcp_has_pli	(	char *	packet,
		int	len )

Method to check whether an RTCP message contains a PLI request.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

TRUE in case of success, FALSE otherwise

janus_rtcp_nacks()

int janus_rtcp_nacks	(	char *	packet,
		int	len,
		GSList *	nacks )

Method to generate a new RTCP NACK message to report lost packets.

Parameters

[in]	packet	The buffer data (MUST be at least 16 chars)
[in]	len	The message data length in bytes (MUST be 16)
[in]	nacks	List of packets to NACK

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_parse()

int janus_rtcp_parse	(	janus_rtcp_context *	ctx,
		char *	packet,
		int	len )

Method to parse/validate an RTCP message.

Parameters

[in]	ctx	RTCP context to update, if needed (optional)
[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

0 in case of success, -1 on errors

janus_rtcp_pli()

int janus_rtcp_pli	(	char *	packet,
		int	len )

Method to generate a new RTCP PLI message to request a key frame.

Parameters

[in]	packet	The buffer data (MUST be at least 12 chars)
[in]	len	The message data length in bytes (MUST be 12)

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_process_incoming_rtp()

int janus_rtcp_process_incoming_rtp	(	janus_rtcp_context *	ctx,
		char *	packet,
		int	len,
		gboolean	rfc4588_pkt,
		gboolean	rfc4588_enabled,
		gboolean	retransmissions_disabled,
		GHashTable *	clock_rates )

Method to quickly process the header of an incoming RTP packet to update the associated RTCP context.

Parameters

[in]	ctx	RTCP context to update, if needed (optional)
[in]	packet	The RTP packet
[in]	len	The packet data length in bytes
[in]	rfc4588_pkt	True if this is a RTX packet
[in]	rfc4588_enabled	True if this packet comes from a RTX enabled stream
[in]	retransmissions_disabled	True if retransmissions are not supported at all for this stream
[in]	clock_rates	Mapping between payload types and clock rates, if available

Returns

0 in case of success, -1 on errors

janus_rtcp_remb()

int janus_rtcp_remb	(	char *	packet,
		int	len,
		uint32_t	bitrate )

Method to generate a new RTCP REMB message to cap the reported bitrate.

Parameters

[in]	packet	The buffer data (MUST be at least 24 chars)
[in]	len	The message data length in bytes (MUST be 24)
[in]	bitrate	The bitrate to report (e.g., 128000)

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_remb_ssrcs()

int janus_rtcp_remb_ssrcs	(	char *	packet,
		int	len,
		uint32_t	bitrate,
		uint8_t	numssrc )

Method to generate a new RTCP REMB message to cap the reported bitrate, but for more SSRCs.

Parameters

[in]	packet	The buffer data (MUST be at least 24 chars)
[in]	len	The message data length in bytes (MUST be 24)
[in]	bitrate	The bitrate to report (e.g., 128000)
[in]	numssrc	The number of SSRCs to include in the request

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_remove_nacks()

int janus_rtcp_remove_nacks	(	char *	packet,
		int	len )

Method to remove an RTCP NACK message.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes

Returns

The new message data length in bytes

Note

This is mostly a placeholder: for the sake of simplicity, whenever we handle some sequence numbers in a NACK, we remove the NACK as a whole before forwarding the RTCP message. Future versions will only selectively remove the sequence numbers that have been handled.

janus_rtcp_report_block()

int janus_rtcp_report_block	(	janus_rtcp_context *	ctx,
		janus_report_block *	rb )

Method to fill in a Report Block in a Receiver Report.

Parameters

[in]	ctx	The RTCP context to use for the report
[in]	rb	Pointer to a valid report_block area of the RTCP data

Returns

0 in case of success, -1 on errors

janus_rtcp_sdes_cname()

int janus_rtcp_sdes_cname	(	char *	packet,
		int	len,
		const char *	cname,
		int	cnamelen )

Method to generate a new RTCP SDES message.

Parameters

[in]	packet	The buffer data
[in]	len	The buffer data length in bytes
[in]	cname	The CNAME to write
[in]	cnamelen	The CNAME data length in bytes

Returns

The message data length in bytes, if successful, -1 on errors

janus_rtcp_swap_report_blocks()

void janus_rtcp_swap_report_blocks	(	char *	packet,
		int	len,
		uint32_t	rtx_ssrc )

Method to swap Report Blocks and move media RB in first position in case rtx SSRC comes first.

Parameters

[in]	packet	The message data
[in]	len	The message data length in bytes
[in]	rtx_ssrc	The rtx SSRC

janus_rtcp_transport_wide_cc_feedback()

int janus_rtcp_transport_wide_cc_feedback	(	char *	packet,
		size_t	len,
		guint32	ssrc,
		guint32	media,
		guint8	feedback_packet_count,
		GQueue *	transport_wide_cc_stats )

Method to generate a new RTCP transport wide message to report reception stats.

Parameters

[in]	packet	The buffer data (MUST be at least 16 chars)
[in]	len	The message data length in bytes
[in]	ssrc	SSRC of the origin stream
[in]	media	SSRC of the destination stream
[in]	feedback_packet_count	Feedback paccket count
[in]	transport_wide_cc_stats	List of rtp packet reception stats

Returns

The message data length in bytes, if successful, -1 on errors