/**
* @brief Start or continue a synchronization session.
* Continue a synchronization session identified by a given command.
* The command must contain a pointer to a valid peer.
* @param driver The driver.
* @param fd The file descriptor to be used for communication.
* @param command The previous sync command.
* @retval 0 On success.
* @retval >0 If the synchronization failed.
*/
static int _applemidi_sync( struct MIDIDriverAppleMIDI * driver, int fd, struct AppleMIDICommand * command ) {
unsigned long ssrc;
MIDITimestamp timestamp, diff;
RTPSessionGetSSRC( driver->rtp_session, &ssrc );
MIDIClockGetNow( driver->base.clock, ×tamp );
if( command->type != APPLEMIDI_COMMAND_SYNCHRONIZATION ||
command->data.sync.ssrc == ssrc ||
command->data.sync.count > 2 ) {
command->type = APPLEMIDI_COMMAND_SYNCHRONIZATION;
command->data.sync.ssrc = ssrc;
command->data.sync.count = 0;
command->data.sync.timestamp1 = timestamp;
driver->sync = 1;
return _applemidi_send_command( driver, fd, command );
} else {
RTPSessionFindPeerBySSRC( driver->rtp_session, &(driver->peer), command->data.sync.ssrc );
/* received packet from other peer */
if( command->data.sync.count == 2 ) {
/* compute media delay */
diff = ( command->data.sync.timestamp3 - command->data.sync.timestamp1 ) / 2;
/* approximate time difference between peer and self */
diff = command->data.sync.timestamp3 + diff - timestamp;
/* RTPPeerSetTimestampDiff( command->peer, diff ) */
/* finished sync */
command->data.sync.ssrc = ssrc;
command->data.sync.count = 3;
driver->sync = 0;
return 0;
}
if( command->data.sync.count == 1 ) {
/* compute media delay */
diff = ( command->data.sync.timestamp3 - command->data.sync.timestamp1 ) / 2;
/* approximate time difference between peer and self */
diff = command->data.sync.timestamp2 + diff - timestamp;
/* RTPPeerSetTimestampDiff( command->peer, diff ) */
command->data.sync.ssrc = ssrc;
command->data.sync.count = 2;
command->data.sync.timestamp3 = timestamp;
driver->sync = 0;
return _applemidi_send_command( driver, fd, command );
}
if( command->data.sync.count == 0 ) {
command->data.sync.ssrc = ssrc;
command->data.sync.count = 1;
command->data.sync.timestamp2 = timestamp;
driver->sync = 2;
return _applemidi_send_command( driver, fd, command );
}
}
return 1;
}
/**
* @brief Respond to a given AppleMIDI command.
* Use the command as response and - if neccessary - send it back to the peer.
* @private @memberof MIDIDriverAppleMIDI
* @param driver The driver.
* @param fd The file descriptor to be used for communication.
* @param command The command.
* @retval 0 On success.
* @retval >0 If the packet could not be sent.
*/
static int _applemidi_respond(struct MIDIDriverAppleMIDI *driver,
struct sock *sk, struct AppleMIDICommand *command)
{
struct RTPPeer *peer = NULL;
switch (command->type) {
case APPLEMIDI_COMMAND_INVITATION:
if (sk == driver->control_socket->sk) {
// event = MIDIEventCreate(
// MIDI_APPLEMIDI_PEER_DID_SEND_INVITATION, NULL, "%s",
// &(command->data.session.name[0]) );
// MIDIDriverTriggerEvent( &(driver->base), event );
// MIDIEventRelease( event );
}
if (driver->accept) {
command->type = APPLEMIDI_COMMAND_INVITATION_ACCEPTED;
if (sk == driver->rtp_socket->sk) {
peer = RTPPeerCreate(
command->data.session.ssrc, command->size,
(struct sockaddr_in *)&(command->addr));
RTPSessionAddPeer(driver->rtp_session, peer);
RTPPeerRelease(peer);
}
} else {
command->type = APPLEMIDI_COMMAND_INVITATION_REJECTED;
}
RTPSessionGetSSRC(driver->rtp_session,
&(command->data.session.ssrc));
pr_debug("processed invitation should now answer\n");
return _applemidi_send_command(driver, sk, command);
case APPLEMIDI_COMMAND_INVITATION_ACCEPTED:
// TODO for receive
break;
case APPLEMIDI_COMMAND_INVITATION_REJECTED:
// TODO for receive
break;
case APPLEMIDI_COMMAND_ENDSESSION:
RTPSessionFindPeerBySSRC(driver->rtp_session, &peer,
command->data.session.ssrc);
// event = MIDIEventCreate( MIDI_APPLEMIDI_PEER_DID_END_SESSION,
// NULL, "%s", &(command->data.session.name[0]) );
// MIDIDriverTriggerEvent( &(driver->base), event );
// MIDIEventRelease( event );
if (peer != NULL) {
RTPSessionRemovePeer(driver->rtp_session, peer);
}
break;
case APPLEMIDI_COMMAND_SYNCHRONIZATION:
return _applemidi_sync(driver, sk, command);
case APPLEMIDI_COMMAND_RECEIVER_FEEDBACK:
// RTPSessionFindPeerBySSRC( driver->rtp_session, &peer,
// command->data.feedback.ssrc );
// RTPMIDISessionJournalTrunkate( driver->rtpmidi_session, peer,
// command->data.feedback.seqnum );
break;
default:
return 1;
}
return 0;
}
static int _applemidi_start_sync( struct MIDIDriverAppleMIDI * driver, int fd, socklen_t size, struct sockaddr * addr ) {
if( addr != (struct sockaddr *) &(driver->command.addr) ) memcpy( &(driver->command.addr), addr, size );
driver->command.size = size;
driver->command.type = APPLEMIDI_COMMAND_SYNCHRONIZATION;
driver->command.data.sync.count = 3;
RTPSessionGetSSRC( driver->rtp_session, &(driver->command.data.sync.ssrc) );
return _applemidi_sync( driver, fd, &(driver->command) );
}
static int _applemidi_endsession( struct MIDIDriverAppleMIDI * driver, int fd, socklen_t size, struct sockaddr * addr ) {
if( addr != (struct sockaddr *) &(driver->command.addr) ) memcpy( &(driver->command.addr), addr, size );
driver->command.size = size;
driver->command.type = APPLEMIDI_COMMAND_ENDSESSION;
driver->command.data.session.version = 2;
driver->command.data.session.token = driver->token;
RTPSessionGetSSRC( driver->rtp_session, &(driver->command.data.session.ssrc) );
strncpy( &(driver->command.data.session.name[0]), driver->name,
sizeof(driver->command.data.session.name) );
return _applemidi_send_command( driver, fd, &(driver->command) );
}
/**
* @brief Respond to a given AppleMIDI command.
* Use the command as response and - if neccessary - send it back to the peer.
* @private @memberof MIDIDriverAppleMIDI
* @param driver The driver.
* @param fd The file descriptor to be used for communication.
* @param command The command.
* @retval 0 On success.
* @retval >0 If the packet could not be sent.
*/
static int _applemidi_respond( struct MIDIDriverAppleMIDI * driver, int fd, struct AppleMIDICommand * command ) {
struct RTPPeer * peer = NULL;
struct MIDIEvent * event = NULL;
switch( command->type ) {
case APPLEMIDI_COMMAND_INVITATION:
if( fd == driver->control_socket ) {
event = MIDIEventCreate( MIDI_APPLEMIDI_PEER_DID_SEND_INVITATION, NULL, "%s", &(command->data.session.name[0]) );
MIDIDriverTriggerEvent( &(driver->base), event );
MIDIEventRelease( event );
}
if( driver->accept ) {
command->type = APPLEMIDI_COMMAND_INVITATION_ACCEPTED;
if( fd == driver->rtp_socket ) {
peer = RTPPeerCreate( command->data.session.ssrc, command->size, (struct sockaddr *) &(command->addr) );
RTPSessionAddPeer( driver->rtp_session, peer );
RTPPeerRelease( peer );
}
} else {
command->type = APPLEMIDI_COMMAND_INVITATION_REJECTED;
}
RTPSessionGetSSRC( driver->rtp_session, &(command->data.session.ssrc) );
return _applemidi_send_command( driver, fd, command );
case APPLEMIDI_COMMAND_INVITATION_ACCEPTED:
if( command->data.session.token == driver->token ) {
if( fd == driver->control_socket ) {
_applemidi_rtp_addr( command->size, (struct sockaddr *) &command->addr, (struct sockaddr *) &command->addr );
return _applemidi_invite( driver, driver->rtp_socket, command->size, (struct sockaddr *) &(command->addr) );
} else {
peer = RTPPeerCreate( command->data.session.ssrc, command->size, (struct sockaddr *) &(command->addr) );
RTPSessionAddPeer( driver->rtp_session, peer );
event = MIDIEventCreate( MIDI_APPLEMIDI_PEER_DID_ACCEPT_INVITATION, NULL, "%s", &(command->data.session.name[0]) );
MIDIDriverTriggerEvent( &(driver->base), event );
MIDIEventRelease( event );
RTPPeerRelease( peer );
return _applemidi_start_sync( driver, driver->rtp_socket, command->size, (struct sockaddr *) &(command->addr) );
}
}
break;
case APPLEMIDI_COMMAND_INVITATION_REJECTED:
event = MIDIEventCreate( MIDI_APPLEMIDI_PEER_DID_REJECT_INVITATION, NULL, "%s", &(command->data.session.name[0]) );
MIDIDriverTriggerEvent( &(driver->base), event );
MIDIEventRelease( event );
break;
case APPLEMIDI_COMMAND_ENDSESSION:
RTPSessionFindPeerBySSRC( driver->rtp_session, &peer, command->data.session.ssrc );
event = MIDIEventCreate( MIDI_APPLEMIDI_PEER_DID_END_SESSION, NULL, "%s", &(command->data.session.name[0]) );
MIDIDriverTriggerEvent( &(driver->base), event );
MIDIEventRelease( event );
if( peer != NULL ) {
RTPSessionRemovePeer( driver->rtp_session, peer );
}
break;
case APPLEMIDI_COMMAND_SYNCHRONIZATION:
return _applemidi_sync( driver, fd, command );
case APPLEMIDI_COMMAND_RECEIVER_FEEDBACK:
RTPSessionFindPeerBySSRC( driver->rtp_session, &peer, command->data.feedback.ssrc );
RTPMIDISessionJournalTrunkate( driver->rtpmidi_session, peer, command->data.feedback.seqnum );
break;
default:
return 1;
}
return 0;
}