toxcore/toxav/rtp.c

528 lines
14 KiB
C

/** 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 queue_message(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)
/**
* Checks if message came in late.
*/
static 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;
}
/**
* Extracts header from payload.
*/
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;
}
memcpy(&retu->sequnum, payload, sizeof(retu->sequnum));
retu->sequnum = ntohs(retu->sequnum);
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 );
int total = 12 /* Minimum header len */ + ( cc * 4 );
if ( length < total ) {
/* Deallocate */
LOGGER_WARNING("Length invalid!");
free(retu);
return NULL;
}
memset(retu->csrc, 0, 16 * sizeof (uint32_t));
retu->marker_payloadt = *it;
++it;
retu->length = total;
memcpy(&retu->timestamp, it, sizeof(retu->timestamp));
retu->timestamp = ntohl(retu->timestamp);
it += 4;
memcpy(&retu->ssrc, it, sizeof(retu->ssrc));
retu->ssrc = ntohl(retu->ssrc);
uint8_t x;
for ( x = 0; x < cc; x++ ) {
it += 4;
memcpy(&retu->csrc[x], it, sizeof(retu->csrc[x]));
retu->csrc[x] = ntohl(retu->csrc[x]);
}
return retu;
}
/**
* Extracts external header from payload. Must be called AFTER extract_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;
memcpy(&ext_length, it, sizeof(ext_length));
ext_length = ntohs(ext_length);
it += 2;
if ( length < ( ext_length * sizeof(uint32_t) ) ) {
LOGGER_WARNING("Length invalid!");
free(retu);
return NULL;
}
retu->length = ext_length;
memcpy(&retu->type, it, sizeof(retu->type));
retu->type = ntohs(retu->type);
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;
memcpy(&(retu->table[x]), it, sizeof(retu->table[x]));
retu->table[x] = ntohl(retu->table[x]);
}
return retu;
}
/**
* Adds header to payload. Make sure _payload_ has enough space.
*/
uint8_t *add_header ( RTPHeader *header, uint8_t *payload )
{
uint8_t cc = GET_FLAG_CSRCC ( header );
uint8_t *it = payload;
uint16_t sequnum;
uint32_t timestamp;
uint32_t ssrc;
uint32_t csrc;
/* Add sequence number first */
sequnum = htons(header->sequnum);
memcpy(it, &sequnum, sizeof(sequnum));
it += 2;
*it = header->flags;
++it;
*it = header->marker_payloadt;
++it;
timestamp = htonl(header->timestamp);
memcpy(it, &timestamp, sizeof(timestamp));
it += 4;
ssrc = htonl(header->ssrc);
memcpy(it, &ssrc, sizeof(ssrc));
uint8_t x;
for ( x = 0; x < cc; x++ ) {
it += 4;
csrc = htonl(header->csrc[x]);
memcpy(it, &csrc, sizeof(csrc));
}
return it + 4;
}
/**
* Adds extension header to payload. Make sure _payload_ has enough space.
*/
uint8_t *add_ext_header ( RTPExtHeader *header, uint8_t *payload )
{
uint8_t *it = payload;
uint16_t length;
uint16_t type;
uint32_t entry;
length = htons(header->length);
memcpy(it, &length, sizeof(length));
it += 2;
type = htons(header->type);
memcpy(it, &type, sizeof(type));
it -= 2; /* Return to 0 position */
if ( header->table ) {
uint16_t x;
for ( x = 0; x < header->length; x++ ) {
it += 4;
entry = htonl(header->table[x]);
memcpy(it, &entry, sizeof(entry));
}
}
return it + 4;
}
/**
* Builds header from control session values.
*/
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;
}
/**
* Parses data into RTPMessage struct. Stores headers separately from the payload data
* and so the length variable is set accordingly.
*/
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;
}
/**
* Callback for networking core.
*/
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;
}
queue_message(session, msg);
return 0;
}
/**
* Allocate message and store data there
*/
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;
}
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 ) return -1;
if ( -1 == send_custom_lossy_packet(messenger, session->dest, msg->data, msg->length) ) {
LOGGER_WARNING("Failed to send full packet (len: %d)! std error: %s", length, strerror(errno));
rtp_free_msg ( session, msg );
return rtp_ErrorSending;
}
/* Set sequ number */
session->sequnum = session->sequnum >= MAX_SEQU_NUM ? 0 : session->sequnum + 1;
rtp_free_msg ( session, msg );
return 0;
}
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 );
}
RTPSession *rtp_new ( 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 = 0;
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;
}
void rtp_kill ( 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 );
}