hdr_builder.c

一个关于 RTP的例子

/*******
**
** FILE INFO:
** project:	RTP_lib
** file:	Hdr_Builder.c
** started on:	04/11/03
** started by:	Cedric Lacroix <[e-mail]>
**
**
** TODO:
**
** BUGS:
**
** UPDATE INFO:
** updated on:	05/13/03
** updated by:	Cedric Lacroix <[e-mail]>
**
********/


#include		<sys/types.h>
#include		<sys/socket.h>

#include		<netinet/in.h>
#include		<arpa/inet.h>

#include		<stdio.h>
#include		<stdlib.h>
#include		<string.h>
#include		<unistd.h>
#include		<err.h>

#include 		"Config.h"
#include 		"RTP.h"
#include 		"Macros.h"
#include 		"Types.h"
#include 		"Proto.h"




/**
 **  Set the version of RTP
 **/
int			Set_Version(rtp_hdr *header)
{
	F_V_FLAGS(header->flags,RTP_VERSION);

	return (0);
}

/* Set the padding flag */
int			Set_Padding(rtp_hdr *header, int value)
{
	if (value > 0)
		F_P_FLAGS(header->flags,1);
	else
		F_P_FLAGS(header->flags,0);
	return (0);
}

/* Set the extention flag */
int			Set_Ext(rtp_hdr *header, int ext_len)
{
	if (ext_len > 0)
		F_X_FLAGS(header->flags,1);
	else
		F_X_FLAGS(header->flags,0);
	return (0);
}


/* Set CSRC count */
int			Set_CSRC_Cnt(rtp_hdr *header, int cc)
{
	F_CC_FLAGS(header->flags,cc);
	return (0);
}


/* Set the marker flag */
int			Set_Marker(rtp_hdr *header, int marker_flg)
{
	F_M_MKPT(header->mk_pt,marker_flg);
	return (0);
}

/* Set the payload type */
int			Set_Payload_Type(rtp_hdr *header, int pti)
{
	F_PT_MKPT(header->mk_pt,pti);
	return (0);
}

/* Set the sequence number */
int			Set_Seq_Nb(rtp_hdr *header, u_int16 sq_nb)
{
	header->sq_nb = htons(sq_nb);
	return (0);
}

/* Set the timestamp */
int			Set_TS(rtp_hdr *header, u_int32 ts)
{
	header->ts = htonl(ts);
	return (0);
}

/* Set the synchronisation source */
int			Set_SSRC(rtp_hdr *header, u_int32 ssrc)
{
	header->ssrc = htonl(ssrc);
	return (0);
}


int			RTP_Build_Header(
					context			cid,
					rtp_hdr			*rtp_header,
					int			padding,
					u_int8			marker,
					int			ext,
					sess_context_t		*context_list,
					u_int16			pti,
					u_int32			ts
					)
{
	Set_Version(rtp_header);
	Set_Padding(rtp_header, padding);
	Set_Ext(rtp_header, ext);
	Set_CSRC_Cnt(rtp_header, context_list->CSRClen);
	Set_Marker(rtp_header, marker);
	Set_Payload_Type(rtp_header, pti);
	Set_Seq_Nb(rtp_header, context_list->seq_no);
	Set_TS(rtp_header, ts);
	Set_SSRC(rtp_header, context_list->my_ssrc);
	return (0);
}