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/** rtp.c
*
* Copyright (C) 2013 Tox project All Rights Reserved.
*
* This file is part of Tox.
*
* Tox is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Tox is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Tox. If not, see <http://www.gnu.org/licenses/>.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif /* HAVE_CONFIG_H */
#include "../toxcore/logger.h"
#include "../toxcore/util.h"
#include "rtp.h"
#include <stdlib.h>
void toxav_handle_packet(RTPSession *_session, RTPMessage *_msg);
#define size_32 4
#define ADD_FLAG_VERSION(_h, _v) do { ( _h->flags ) &= 0x3F; ( _h->flags ) |= ( ( ( _v ) << 6 ) & 0xC0 ); } while(0)
#define ADD_FLAG_PADDING(_h, _v) do { if ( _v > 0 ) _v = 1; ( _h->flags ) &= 0xDF; ( _h->flags ) |= ( ( ( _v ) << 5 ) & 0x20 ); } while(0)
#define ADD_FLAG_EXTENSION(_h, _v) do { if ( _v > 0 ) _v = 1; ( _h->flags ) &= 0xEF;( _h->flags ) |= ( ( ( _v ) << 4 ) & 0x10 ); } while(0)
#define ADD_FLAG_CSRCC(_h, _v) do { ( _h->flags ) &= 0xF0; ( _h->flags ) |= ( ( _v ) & 0x0F ); } while(0)
#define ADD_SETTING_MARKER(_h, _v) do { if ( _v > 1 ) _v = 1; ( _h->marker_payloadt ) &= 0x7F; ( _h->marker_payloadt ) |= ( ( ( _v ) << 7 ) /*& 0x80 */ ); } while(0)
#define ADD_SETTING_PAYLOAD(_h, _v) do { if ( _v > 127 ) _v = 127; ( _h->marker_payloadt ) &= 0x80; ( _h->marker_payloadt ) |= ( ( _v ) /* & 0x7F */ ); } while(0)
#define GET_FLAG_VERSION(_h) (( _h->flags & 0xd0 ) >> 6)
#define GET_FLAG_PADDING(_h) (( _h->flags & 0x20 ) >> 5)
#define GET_FLAG_EXTENSION(_h) (( _h->flags & 0x10 ) >> 4)
#define GET_FLAG_CSRCC(_h) ( _h->flags & 0x0f )
#define GET_SETTING_MARKER(_h) (( _h->marker_payloadt ) >> 7)
#define GET_SETTING_PAYLOAD(_h) ((_h->marker_payloadt) & 0x7f)
/**
* @brief Checks if message came in late.
*
* @param session Control session.
* @param msg The message.
* @return int
* @retval -1 The message came in order.
* @retval 0 The message came late.
*/
inline__ int check_late_message (RTPSession *session, RTPMessage *msg)
{
/*
* Check Sequence number. If this new msg has lesser number then the session->rsequnum
* it shows that the message came in late. Also check timestamp to be 100% certain.
*
*/
return ( msg->header->sequnum < session->rsequnum && msg->header->timestamp < session->timestamp ) ? 0 : -1;
}
/**
* @brief Extracts header from payload.
*
* @param payload The payload.
* @param length The size of payload.
* @return RTPHeader* Extracted header.
* @retval NULL Error occurred while extracting header.
*/
RTPHeader *extract_header ( const uint8_t *payload, int length )
{
if ( !payload || !length ) {
LOGGER_WARNING("No payload to extract!");
return NULL;
}
RTPHeader *_retu = calloc(1, sizeof (RTPHeader));
if ( !_retu ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
return NULL;
}
bytes_to_U16(&_retu->sequnum, payload);
const uint8_t *_it = payload + 2;
_retu->flags = *_it;
++_it;
/* This indicates if the first 2 bits are valid.
* Now it may happen that this is out of order but
* it cuts down chances of parsing some invalid value
*/
if ( GET_FLAG_VERSION(_retu) != RTP_VERSION ) {
/* Deallocate */
LOGGER_WARNING("Invalid version!");
free(_retu);
return NULL;
}
/*
* Added a check for the size of the header little sooner so
* I don't need to parse the other stuff if it's bad
*/
uint8_t _cc = GET_FLAG_CSRCC ( _retu );
uint32_t _length = 12 /* Minimum header len */ + ( _cc * 4 );
if ( length < _length ) {
/* Deallocate */
LOGGER_WARNING("Length invalid!");
free(_retu);
return NULL;
}
memset(_retu->csrc, 0, 16 * sizeof (uint32_t));
_retu->marker_payloadt = *_it;
++_it;
_retu->length = _length;
bytes_to_U32(&_retu->timestamp, _it);
_it += 4;
bytes_to_U32(&_retu->ssrc, _it);
uint8_t _x;
for ( _x = 0; _x < _cc; _x++ ) {
_it += 4;
bytes_to_U32(&(_retu->csrc[_x]), _it);
}
return _retu;
}
/**
* @brief Extracts external header from payload. Must be called AFTER extract_header()!
*
* @param payload The ITERATED payload.
* @param length The size of payload.
* @return RTPExtHeader* Extracted extension header.
* @retval NULL Error occurred while extracting extension header.
*/
RTPExtHeader *extract_ext_header ( const uint8_t *payload, uint16_t length )
{
const uint8_t *_it = payload;
RTPExtHeader *_retu = calloc(1, sizeof (RTPExtHeader));
if ( !_retu ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
return NULL;
}
uint16_t _ext_length;
bytes_to_U16(&_ext_length, _it);
_it += 2;
if ( length < ( _ext_length * sizeof(uint32_t) ) ) {
LOGGER_WARNING("Length invalid!");
free(_retu);
return NULL;
}
_retu->length = _ext_length;
bytes_to_U16(&_retu->type, _it);
_it += 2;
if ( !(_retu->table = calloc(_ext_length, sizeof (uint32_t))) ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
free(_retu);
return NULL;
}
uint16_t _x;
for ( _x = 0; _x < _ext_length; _x++ ) {
_it += 4;
bytes_to_U32(&(_retu->table[_x]), _it);
}
return _retu;
}
/**
* @brief Adds header to payload. Make sure _payload_ has enough space.
*
* @param header The header.
* @param payload The payload.
* @return uint8_t* Iterated position.
*/
uint8_t *add_header ( RTPHeader *header, uint8_t *payload )
{
uint8_t _cc = GET_FLAG_CSRCC ( header );
uint8_t *_it = payload;
/* Add sequence number first */
U16_to_bytes(_it, header->sequnum);
_it += 2;
*_it = header->flags;
++_it;
*_it = header->marker_payloadt;
++_it;
U32_to_bytes( _it, header->timestamp);
_it += 4;
U32_to_bytes( _it, header->ssrc);
uint8_t _x;
for ( _x = 0; _x < _cc; _x++ ) {
_it += 4;
U32_to_bytes( _it, header->csrc[_x]);
}
return _it + 4;
}
/**
* @brief Adds extension header to payload. Make sure _payload_ has enough space.
*
* @param header The header.
* @param payload The payload.
* @return uint8_t* Iterated position.
*/
uint8_t *add_ext_header ( RTPExtHeader *header, uint8_t *payload )
{
uint8_t *_it = payload;
U16_to_bytes(_it, header->length);
_it += 2;
U16_to_bytes(_it, header->type);
_it -= 2; /* Return to 0 position */
if ( header->table ) {
uint16_t _x;
for ( _x = 0; _x < header->length; _x++ ) {
_it += 4;
U32_to_bytes(_it, header->table[_x]);
}
}
return _it + 4;
}
/**
* @brief Builds header from control session values.
*
* @param session Control session.
* @return RTPHeader* Created header.
*/
RTPHeader *build_header ( RTPSession *session )
{
RTPHeader *_retu = calloc ( 1, sizeof (RTPHeader) );
if ( !_retu ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
return NULL;
}
ADD_FLAG_VERSION ( _retu, session->version );
ADD_FLAG_PADDING ( _retu, session->padding );
ADD_FLAG_EXTENSION ( _retu, session->extension );
ADD_FLAG_CSRCC ( _retu, session->cc );
ADD_SETTING_MARKER ( _retu, session->marker );
ADD_SETTING_PAYLOAD ( _retu, session->payload_type );
_retu->sequnum = session->sequnum;
_retu->timestamp = current_time_monotonic(); /* milliseconds */
_retu->ssrc = session->ssrc;
int i;
for ( i = 0; i < session->cc; i++ )
_retu->csrc[i] = session->csrc[i];
_retu->length = 12 /* Minimum header len */ + ( session->cc * size_32 );
return _retu;
}
/**
* @brief Parses data into RTPMessage struct. Stores headers separately from the payload data
* and so the length variable is set accordingly. _sequnum_ argument is
* passed by the handle_packet() since it's parsed already.
*
* @param session Control session.
* @param sequnum Sequence number that's parsed from payload in handle_packet()
* @param data Payload data.
* @param length Payload size.
* @return RTPMessage*
* @retval NULL Error occurred.
*/
RTPMessage *msg_parse ( const uint8_t *data, int length )
{
RTPMessage *_retu = calloc(1, sizeof (RTPMessage));
_retu->header = extract_header ( data, length ); /* It allocates memory and all */
if ( !_retu->header ) {
LOGGER_WARNING("Header failed to extract!");
free(_retu);
return NULL;
}
uint16_t _from_pos = _retu->header->length;
_retu->length = length - _from_pos;
if ( GET_FLAG_EXTENSION ( _retu->header ) ) {
_retu->ext_header = extract_ext_header ( data + _from_pos, length );
if ( _retu->ext_header ) {
_retu->length -= ( 4 /* Minimum ext header len */ + _retu->ext_header->length * size_32 );
_from_pos += ( 4 /* Minimum ext header len */ + _retu->ext_header->length * size_32 );
} else { /* Error */
LOGGER_WARNING("Ext Header failed to extract!");
rtp_free_msg(NULL, _retu);
return NULL;
}
} else {
_retu->ext_header = NULL;
}
if ( length - _from_pos <= MAX_RTP_SIZE )
memcpy ( _retu->data, data + _from_pos, length - _from_pos );
else {
LOGGER_WARNING("Invalid length!");
rtp_free_msg(NULL, _retu);
return NULL;
}
_retu->next = NULL;
return _retu;
}
/**
* @brief Callback for networking core.
*
* @param object RTPSession object.
* @param ip_port Where the message comes from.
* @param data Message data.
* @param length Message length.
* @return int
* @retval -1 Error occurred.
* @retval 0 Success.
*/
int rtp_handle_packet ( void *object, const uint8_t *data, uint32_t length )
{
RTPSession *_session = object;
RTPMessage *_msg;
if ( !_session || length < 13 ) { /* 12 is the minimum length for rtp + desc. byte */
LOGGER_WARNING("No session or invalid length of received buffer!");
return -1;
}
_msg = msg_parse ( data + 1, length - 1 );
if ( !_msg ) {
LOGGER_WARNING("Could not parse message!");
return -1;
}
/* Check if message came in late */
if ( check_late_message(_session, _msg) < 0 ) { /* Not late */
_session->rsequnum = _msg->header->sequnum;
_session->timestamp = _msg->header->timestamp;
}
toxav_handle_packet(_session, _msg);
return 0;
}
/**
* @brief Stores headers and payload data in one container ( data )
* and the length is set accordingly. Returned message is used for sending _only_.
*
* @param session The control session.
* @param data Payload data to send ( This is what you pass ).
* @param length Size of the payload data.
* @return RTPMessage* Created message.
* @retval NULL Error occurred.
*/
RTPMessage *rtp_new_message ( RTPSession *session, const uint8_t *data, uint32_t length )
{
if ( !session ) {
LOGGER_WARNING("No session!");
return NULL;
}
uint8_t *_from_pos;
RTPMessage *_retu = calloc(1, sizeof (RTPMessage));
if ( !_retu ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
return NULL;
}
/* Sets header values and copies the extension header in _retu */
_retu->header = build_header ( session ); /* It allocates memory and all */
_retu->ext_header = session->ext_header;
uint32_t _total_length = length + _retu->header->length + 1;
_retu->data[0] = session->prefix;
if ( _retu->ext_header ) {
_total_length += ( 4 /* Minimum ext header len */ + _retu->ext_header->length * size_32 );
_from_pos = add_header ( _retu->header, _retu->data + 1 );
_from_pos = add_ext_header ( _retu->ext_header, _from_pos + 1 );
} else {
_from_pos = add_header ( _retu->header, _retu->data + 1 );
}
/*
* Parses the extension header into the message
* Of course if any
*/
/* Appends _data on to _retu->_data */
memcpy ( _from_pos, data, length );
_retu->length = _total_length;
_retu->next = NULL;
return _retu;
}
/**
* @brief Sends data to _RTPSession::dest
*
* @param session The session.
* @param messenger Tox* object.
* @param data The payload.
* @param length Size of the payload.
* @return int
* @retval -1 On error.
* @retval 0 On success.
*/
int rtp_send_msg ( RTPSession *session, Messenger *messenger, const uint8_t *data, uint16_t length )
{
RTPMessage *msg = rtp_new_message (session, data, length);
if ( !msg ) {
LOGGER_WARNING("No session!");
return -1;
}
if ( -1 == send_custom_lossy_packet(messenger, session->dest, msg->data, msg->length) ) {
LOGGER_WARNING("Failed to send full packet! std error: %s", strerror(errno));
rtp_free_msg ( session, msg );
return -1;
}
/* Set sequ number */
session->sequnum = session->sequnum >= MAX_SEQU_NUM ? 0 : session->sequnum + 1;
rtp_free_msg ( session, msg );
return 0;
}
/**
* @brief Speaks for it self.
*
* @param session The control session msg belongs to. You set it as NULL when freeing recved messages.
* Otherwise set it to session the message was created from.
* @param msg The message.
* @return void
*/
void rtp_free_msg ( RTPSession *session, RTPMessage *msg )
{
if ( !session ) {
if ( msg->ext_header ) {
free ( msg->ext_header->table );
free ( msg->ext_header );
}
} else {
if ( msg->ext_header && session->ext_header != msg->ext_header ) {
free ( msg->ext_header->table );
free ( msg->ext_header );
}
}
free ( msg->header );
free ( msg );
}
/**
* @brief Must be called before calling any other rtp function. It's used
* to initialize RTP control session.
*
* @param payload_type Type of payload used to send. You can use values in toxmsi.h::MSICallType
* @param messenger Tox* object.
* @param friend_num Friend id.
* @return RTPSession* Created control session.
* @retval NULL Error occurred.
*/
RTPSession *rtp_init_session ( int payload_type, Messenger *messenger, int friend_num )
{
RTPSession *_retu = calloc(1, sizeof(RTPSession));
if ( !_retu ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
return NULL;
}
if ( -1 == custom_lossy_packet_registerhandler(messenger, friend_num, payload_type, rtp_handle_packet, _retu)) {
LOGGER_ERROR("Error setting custom register handler for rtp session");
free(_retu);
return NULL;
}
LOGGER_DEBUG("Registered packet handler: pt: %d; fid: %d", payload_type, friend_num);
_retu->version = RTP_VERSION; /* It's always 2 */
_retu->padding = 0; /* If some additional data is needed about the packet */
_retu->extension = 0; /* If extension to header is needed */
_retu->cc = 1; /* Amount of contributors */
_retu->csrc = NULL; /* Container */
_retu->ssrc = random_int();
_retu->marker = 0;
_retu->payload_type = payload_type % 128;
_retu->dest = friend_num;
_retu->rsequnum = _retu->sequnum = 1;
_retu->ext_header = NULL; /* When needed allocate */
if ( !(_retu->csrc = calloc(1, sizeof (uint32_t))) ) {
LOGGER_WARNING("Alloc failed! Program might misbehave!");
free(_retu);
return NULL;
}
_retu->csrc[0] = _retu->ssrc; /* Set my ssrc to the list receive */
/* Also set payload type as prefix */
_retu->prefix = payload_type;
/*
*
*/
return _retu;
}
/**
* @brief Terminate the session.
*
* @param session The session.
* @param messenger The messenger who owns the session
* @return int
* @retval -1 Error occurred.
* @retval 0 Success.
*/
void rtp_terminate_session ( RTPSession *session, Messenger *messenger )
{
if ( !session ) return;
custom_lossy_packet_registerhandler(messenger, session->dest, session->prefix, NULL, NULL);
free ( session->ext_header );
free ( session->csrc );
LOGGER_DEBUG("Terminated RTP session: %p", session);
/* And finally free session */
free ( session );
}
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