minetest_nmpr/src/connection.cpp

#include "connection.h"
#include "main.h"

namespace con
{

BufferedPacket makePacket(Address &address, u8 *data, u32 datasize,
		u32 protocol_id, u16 sender_peer_id, u8 channel)
{
	u32 packet_size = datasize + BASE_HEADER_SIZE;
	BufferedPacket p(packet_size);
	p.address = address;

	writeU32(&p.data[0], protocol_id);
	writeU16(&p.data[4], sender_peer_id);
	writeU8(&p.data[6], channel);

	memcpy(&p.data[BASE_HEADER_SIZE], data, datasize);

	return p;
}

BufferedPacket makePacket(Address &address, SharedBuffer<u8> &data,
		u32 protocol_id, u16 sender_peer_id, u8 channel)
{
	return makePacket(address, *data, data.getSize(),
			protocol_id, sender_peer_id, channel);
}

SharedBuffer<u8> makeOriginalPacket(
		SharedBuffer<u8> data)
{
	u32 header_size = 1;
	u32 packet_size = data.getSize() + header_size;
	SharedBuffer<u8> b(packet_size);

	writeU8(&b[0], TYPE_ORIGINAL);

	memcpy(&b[header_size], *data, data.getSize());

	return b;
}

core::list<SharedBuffer<u8> > makeSplitPacket(
		SharedBuffer<u8> data,
		u32 chunksize_max,
		u16 seqnum)
{
	// Chunk packets, containing the TYPE_SPLIT header
	core::list<SharedBuffer<u8> > chunks;
	
	u32 chunk_header_size = 7;
	u32 maximum_data_size = chunksize_max - chunk_header_size;
	u32 start = 0;
	u32 end = 0;
	u32 chunk_num = 0;
	do{
		end = start + maximum_data_size - 1;
		if(end > data.getSize() - 1)
			end = data.getSize() - 1;
		
		u32 payload_size = end - start + 1;
		u32 packet_size = chunk_header_size + payload_size;

		SharedBuffer<u8> chunk(packet_size);
		
		writeU8(&chunk[0], TYPE_SPLIT);
		writeU16(&chunk[1], seqnum);
		// [3] u16 chunk_count is written at next stage
		writeU16(&chunk[5], chunk_num);
		memcpy(&chunk[chunk_header_size], &data[start], payload_size);

		chunks.push_back(chunk);
		
		start = end + 1;
		chunk_num++;
	}
	while(end != data.getSize() - 1);

	u16 chunk_count = chunks.getSize();

	core::list<SharedBuffer<u8> >::Iterator i = chunks.begin();
	for(; i != chunks.end(); i++)
	{
		// Write chunk_count
		writeU16(&((*i)[3]), chunk_count);
	}

	return chunks;
}

core::list<SharedBuffer<u8> > makeAutoSplitPacket(
		SharedBuffer<u8> data,
		u32 chunksize_max,
		u16 &split_seqnum)
{
	u32 original_header_size = 1;
	core::list<SharedBuffer<u8> > list;
	if(data.getSize() + original_header_size > chunksize_max)
	{
		list = makeSplitPacket(data, chunksize_max, split_seqnum);
		split_seqnum++;
		return list;
	}
	else
	{
		list.push_back(makeOriginalPacket(data));
	}
	return list;
}

SharedBuffer<u8> makeReliablePacket(
		SharedBuffer<u8> data,
		u16 seqnum)
{
	u32 header_size = 3;
	u32 packet_size = data.getSize() + header_size;
	SharedBuffer<u8> b(packet_size);

	writeU8(&b[0], TYPE_RELIABLE);
	writeU16(&b[1], seqnum);

	memcpy(&b[header_size], *data, data.getSize());

	return b;
}

/*
	ReliablePacketBuffer
*/

void ReliablePacketBuffer::print()
{
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	for(; i != m_list.end(); i++)
	{
		u16 s = readU16(&(i->data[BASE_HEADER_SIZE+1]));
		dout_con<<s<<" ";
	}
}
bool ReliablePacketBuffer::empty()
{
	return m_list.empty();
}
u32 ReliablePacketBuffer::size()
{
	return m_list.getSize();
}
RPBSearchResult ReliablePacketBuffer::findPacket(u16 seqnum)
{
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	for(; i != m_list.end(); i++)
	{
		u16 s = readU16(&(i->data[BASE_HEADER_SIZE+1]));
		/*dout_con<<"findPacket(): finding seqnum="<<seqnum
				<<", comparing to s="<<s<<std::endl;*/
		if(s == seqnum)
			break;
	}
	return i;
}
RPBSearchResult ReliablePacketBuffer::notFound()
{
	return m_list.end();
}
u16 ReliablePacketBuffer::getFirstSeqnum()
{
	if(empty())
		throw NotFoundException("Buffer is empty");
	BufferedPacket p = *m_list.begin();
	return readU16(&p.data[BASE_HEADER_SIZE+1]);
}
BufferedPacket ReliablePacketBuffer::popFirst()
{
	if(empty())
		throw NotFoundException("Buffer is empty");
	BufferedPacket p = *m_list.begin();
	core::list<BufferedPacket>::Iterator i = m_list.begin();
	m_list.erase(i);
	return p;
}
BufferedPacket ReliablePacketBuffer::popSeqnum(u16 seqnum)
{
	RPBSearchResult r = findPacket(seqnum);
	if(r == notFound()){
		dout_con<<"Not found"<<std::endl;
		throw NotFoundException("seqnum not found in buffer");
	}
	BufferedPacket p = *r;
	m_list.erase(r);
	return p;
}
void ReliablePacketBuffer::insert(BufferedPacket &p)
{
	assert(p.data.getSize() >= BASE_HEADER_SIZE+3);
	u8 type = readU8(&p.data[BASE_HEADER_SIZE+0]);
	assert(type == TYPE_RELIABLE);
	u16 seqnum = readU16(&p.data[BASE_HEADER_SIZE+1]);

	// Find the right place for the packet and insert it there

	// If list is empty, just add it
	if(m_list.empty())
	{
		m_list.push_back(p);
		// Done.
		return;
	}
	// Otherwise find the right place
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	// Find the first packet in the list which has a higher seqnum
	for(; i != m_list.end(); i++){
		u16 s = readU16(&(i->data[BASE_HEADER_SIZE+1]));
		if(s == seqnum){
			throw AlreadyExistsException("Same seqnum in list");
		}
		if(seqnum_higher(s, seqnum)){
			break;
		}
	}
	// If we're at the end of the list, add the packet to the
	// end of the list
	if(i == m_list.end())
	{
		m_list.push_back(p);
		// Done.
		return;
	}
	// Insert before i
	m_list.insert_before(i, p);
}

void ReliablePacketBuffer::incrementTimeouts(float dtime)
{
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	for(; i != m_list.end(); i++){
		i->time += dtime;
		i->totaltime += dtime;
	}
}

void ReliablePacketBuffer::resetTimedOuts(float timeout)
{
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	for(; i != m_list.end(); i++){
		if(i->time >= timeout)
			i->time = 0.0;
	}
}

core::list<BufferedPacket> ReliablePacketBuffer::getTimedOuts(float timeout)
{
	core::list<BufferedPacket> timed_outs;
	core::list<BufferedPacket>::Iterator i;
	i = m_list.begin();
	for(; i != m_list.end(); i++)
	{
		if(i->time >= timeout)
			timed_outs.push_back(*i);
	}
	return timed_outs;
}

/*
	IncomingSplitBuffer
*/

IncomingSplitBuffer::~IncomingSplitBuffer()
{
	core::map<u16, IncomingSplitPacket*>::Iterator i;
	i = m_buf.getIterator();
	for(; i.atEnd() == false; i++)
	{
		delete i.getNode()->getValue();
	}
}
/*
	This will throw a GotSplitPacketException when a full
	split packet is constructed.
*/
void IncomingSplitBuffer::insert(BufferedPacket &p, bool reliable)
{
	u32 headersize = BASE_HEADER_SIZE + 7;
	assert(p.data.getSize() >= headersize);
	u8 type = readU8(&p.data[BASE_HEADER_SIZE+0]);
	assert(type == TYPE_SPLIT);
	u16 seqnum = readU16(&p.data[BASE_HEADER_SIZE+1]);
	u16 chunk_count = readU16(&p.data[BASE_HEADER_SIZE+3]);
	u16 chunk_num = readU16(&p.data[BASE_HEADER_SIZE+5]);

	// Add if doesn't exist
	if(m_buf.find(seqnum) == NULL)
	{
		IncomingSplitPacket *sp = new IncomingSplitPacket();
		sp->chunk_count = chunk_count;
		sp->reliable = reliable;
		m_buf[seqnum] = sp;
	}
	
	IncomingSplitPacket *sp = m_buf[seqnum];
	
	if(chunk_count != sp->chunk_count)
		dout_con<<"WARNING: chunk_count="<<chunk_count
				<<" != sp->chunk_count="<<sp->chunk_count
				<<std::endl;
	if(reliable != sp->reliable)
		dout_con<<"WARNING: reliable="<<reliable
				<<" != sp->reliable="<<sp->reliable
				<<std::endl;

	// If chunk already exists, cancel
	if(sp->chunks.find(chunk_num) != NULL)
		throw AlreadyExistsException("Chunk already in buffer");
	
	// Cut chunk data out of packet
	u32 chunkdatasize = p.data.getSize() - headersize;
	SharedBuffer<u8> chunkdata(chunkdatasize);
	memcpy(*chunkdata, &(p.data[headersize]), chunkdatasize);
	
	// Set chunk data in buffer
	sp->chunks[chunk_num] = chunkdata;
	
	// If not all chunks are received, return
	if(sp->allReceived() == false)
		return;

	// Calculate total size
	u32 totalsize = 0;
	core::map<u16, SharedBuffer<u8> >::Iterator i;
	i = sp->chunks.getIterator();
	for(; i.atEnd() == false; i++)
	{
		totalsize += i.getNode()->getValue().getSize();
	}
	
	SharedBuffer<u8> fulldata(totalsize);

	// Copy chunks to data buffer
	u32 start = 0;
	for(u32 chunk_i=0; chunk_i<sp->chunk_count;
			chunk_i++)
	{
		SharedBuffer<u8> buf = sp->chunks[chunk_i];
		u16 chunkdatasize = buf.getSize();
		memcpy(&fulldata[start], *buf, chunkdatasize);
		start += chunkdatasize;;
	}

	// Remove sp from buffer
	m_buf.remove(seqnum);
	delete sp;
	
	throw GotSplitPacketException(fulldata);
}
void IncomingSplitBuffer::removeUnreliableTimedOuts(float dtime, float timeout)
{
	core::list<u16> remove_queue;
	core::map<u16, IncomingSplitPacket*>::Iterator i;
	i = m_buf.getIterator();
	for(; i.atEnd() == false; i++)
	{
		IncomingSplitPacket *p = i.getNode()->getValue();
		// Reliable ones are not removed by timeout
		if(p->reliable == true)
			continue;
		p->time += dtime;
		if(p->time >= timeout)
			remove_queue.push_back(i.getNode()->getKey());
	}
	core::list<u16>::Iterator j;
	j = remove_queue.begin();
	for(; j != remove_queue.end(); j++)
	{
		dout_con<<"NOTE: Removing timed out unreliable split packet"
				<<std::endl;
		delete m_buf[*j];
		m_buf.remove(*j);
	}
}

/*
	Channel
*/

Channel::Channel()
{
	next_outgoing_seqnum = SEQNUM_INITIAL;
	next_incoming_seqnum = SEQNUM_INITIAL;
	next_outgoing_split_seqnum = SEQNUM_INITIAL;
}
Channel::~Channel()
{
}

/*
	Peer
*/

Peer::Peer()
{
	id = PEER_ID_NEW;
	timeout_counter = 0.0;
	//resend_timeout = RESEND_TIMEOUT_MINIMUM;
	//resend_timeout = 0.5;
	resend_timeout = 0.2;
	has_sent_with_id = false;
	avg_rtt = 0.5;
}
Peer::~Peer()
{
}

/*
	Connection
*/

Connection::Connection(u32 protocol_id, u32 max_packet_size)
{
	m_protocol_id = protocol_id;
	m_max_packet_size = max_packet_size;
	m_peer_id = PEER_ID_NEW;
	m_waiting_new_peer_id = false;
	m_indentation = 0;
}

Connection::~Connection()
{
	// Clear peers
	core::map<u16, Peer*>::Iterator j;
	j = m_peers.getIterator();
	for(; j.atEnd() == false; j++)
	{
		Peer *peer = j.getNode()->getValue();
		delete peer;
	}
}

void Connection::Serve(unsigned short port)
{
	m_socket.Bind(port);
	m_peer_id = PEER_ID_SERVER;
}

void Connection::Connect(Address address)
{
	core::map<u16, Peer*>::Node *node = m_peers.find(PEER_ID_SERVER);
	if(node != NULL){
		throw ConnectionException("Already connected to a server");
	}

	Peer *peer = new Peer();
	peer->address = address;
	peer->id = PEER_ID_SERVER;
	m_peers.insert(peer->id, peer);
	
	m_socket.Bind(0);
	
	// Send a dummy packet to server with peer_id = PEER_ID_NEW
	m_peer_id = PEER_ID_NEW;
	SharedBuffer<u8> data(0);
	Send(PEER_ID_SERVER, 0, data, true);

	m_waiting_new_peer_id = true;
}

bool Connection::Connected()
{
	if(m_peers.size() != 1)
		return false;
		
	core::map<u16, Peer*>::Node *node = m_peers.find(PEER_ID_SERVER);
	if(node == NULL)
		return false;
	
	if(m_peer_id == PEER_ID_NEW)
		return false;
	
	return true;
}

SharedBuffer<u8> Channel::ProcessPacket(
		SharedBuffer<u8> packetdata,
		Connection *con,
		u16 peer_id,
		u8 channelnum,
		bool reliable)
{
	IndentationRaiser iraiser(&(con->m_indentation));

	if(packetdata.getSize() < 1)
		throw InvalidIncomingDataException("packetdata.getSize() < 1");

	u8 type = readU8(&packetdata[0]);
	
	if(type == TYPE_CONTROL)
	{
		if(packetdata.getSize() < 2)
			throw InvalidIncomingDataException("packetdata.getSize() < 2");

		u8 controltype = readU8(&packetdata[1]);

		if(controltype == CONTROLTYPE_ACK)
		{
			if(packetdata.getSize() < 4)
				throw InvalidIncomingDataException
						("packetdata.getSize() < 4 (ACK header size)");

			u16 seqnum = readU16(&packetdata[2]);
			con->PrintInfo();
			dout_con<<"Got CONTROLTYPE_ACK: channelnum="
					<<((int)channelnum&0xff)<<", peer_id="<<peer_id
					<<", seqnum="<<seqnum<<std::endl;

			try{
				BufferedPacket p = outgoing_reliables.popSeqnum(seqnum);
				// Get round trip time
				float rtt = p.totaltime;
				con->PrintInfo();
				//dout_con<<"RTT = "<<rtt<<std::endl;
				Peer *peer = con->GetPeer(peer_id);
				peer->avg_rtt = rtt * 0.1 + peer->avg_rtt * 0.9;
				// Calculate resend_timeout
				float resend_timeout = peer->avg_rtt * 2.0;
				if(resend_timeout < RESEND_TIMEOUT_MIN)
					resend_timeout = RESEND_TIMEOUT_MIN;
				if(resend_timeout > RESEND_TIMEOUT_MAX)
					resend_timeout = RESEND_TIMEOUT_MAX;
				peer->resend_timeout = resend_timeout;
				
				/*dout_con<<"OUTGOING: ";
				con->PrintInfo();
				outgoing_reliables.print();
				dout_con<<std::endl;*/
			}
			catch(NotFoundException &e){
				con->PrintInfo();
				dout_con<<"WARNING: ACKed packet not in outgoing queue"
						<<std::endl;
			}

			throw ProcessedSilentlyException("Got an ACK");
		}
		else if(controltype == CONTROLTYPE_SET_PEER_ID)
		{
			if(packetdata.getSize() < 4)
				throw InvalidIncomingDataException
						("packetdata.getSize() < 4 (SET_PEER_ID header size)");
			u16 peer_id_new = readU16(&packetdata[2]);
			con->PrintInfo();
			dout_con<<"Got new peer id: "<<peer_id_new<<"... ";

			if(con->GetPeerID() != PEER_ID_NEW)
			{
				dout_con<<"WARNING: not changing."<<std::endl;
			}
			else
			{
				dout_con<<"changing."<<std::endl;
				con->SetPeerID(peer_id_new);
			}
			throw ProcessedSilentlyException("Got a SET_PEER_ID");
		}
		else if(controltype == CONTROLTYPE_PING)
		{
			// Just ignore it, the incoming data already reset
			// the timeout counter
			con->PrintInfo();
			dout_con<<"PING"<<std::endl;
			throw ProcessedSilentlyException("Got a SET_PEER_ID");
		}
		else{
			con->PrintInfo();
			dout_con<<"INVALID TYPE_CONTROL: invalid controltype="
					<<((int)controltype&0xff)<<std::endl;
			throw InvalidIncomingDataException("Invalid control type");
		}
	}
	else if(type == TYPE_ORIGINAL)
	{
		if(packetdata.getSize() < ORIGINAL_HEADER_SIZE)
			throw InvalidIncomingDataException
					("packetdata.getSize() < ORIGINAL_HEADER_SIZE");
		con->PrintInfo();
		dout_con<<"RETURNING TYPE_ORIGINAL to user"
				<<std::endl;
		// Get the inside packet out and return it
		SharedBuffer<u8> payload(packetdata.getSize() - ORIGINAL_HEADER_SIZE);
		memcpy(*payload, &packetdata[ORIGINAL_HEADER_SIZE], payload.getSize());
		return payload;
	}
	else if(type == TYPE_SPLIT)
	{
		// We have to create a packet again for buffering
		// This isn't actually too bad an idea.
		BufferedPacket packet = makePacket(
				con->GetPeer(peer_id)->address,
				packetdata,
				con->GetProtocolID(),
				peer_id,
				channelnum);
		try{
			// Buffer the packet
			incoming_splits.insert(packet, reliable);
		}
		// This exception happens when all the pieces of a packet
		// are collected.
		catch(GotSplitPacketException &e)
		{
			con->PrintInfo();
			dout_con<<"RETURNING TYPE_SPLIT: Constructed full data, "
					<<"size="<<e.getData().getSize()<<std::endl;
			return e.getData();
		}
		con->PrintInfo();
		dout_con<<"BUFFERING TYPE_SPLIT"<<std::endl;
		throw ProcessedSilentlyException("Buffered a split packet chunk");
	}
	else if(type == TYPE_RELIABLE)
	{
		// Recursive reliable packets not allowed
		assert(reliable == false);

		if(packetdata.getSize() < RELIABLE_HEADER_SIZE)
			throw InvalidIncomingDataException
					("packetdata.getSize() < RELIABLE_HEADER_SIZE");

		u16 seqnum = readU16(&packetdata[1]);

		bool is_future_packet = seqnum_higher(seqnum, next_incoming_seqnum);
		bool is_old_packet = seqnum_higher(next_incoming_seqnum, seqnum);
		
		con->PrintInfo();
		if(is_future_packet)
			dout_con<<"BUFFERING";
		else if(is_old_packet)
			dout_con<<"OLD";
		else
			dout_con<<"RECUR";
		dout_con<<" TYPE_RELIABLE seqnum="<<seqnum
				<<" next="<<next_incoming_seqnum;
		dout_con<<" [sending CONTROLTYPE_ACK"
				" to peer_id="<<peer_id<<"]";
		dout_con<<std::endl;
		
		//DEBUG
		//assert(incoming_reliables.size() < 100);

		// Send a CONTROLTYPE_ACK
		SharedBuffer<u8> reply(4);
		writeU8(&reply[0], TYPE_CONTROL);
		writeU8(&reply[1], CONTROLTYPE_ACK);
		writeU16(&reply[2], seqnum);
		con->SendAsPacket(peer_id, channelnum, reply, false);

		//if(seqnum_higher(seqnum, next_incoming_seqnum))
		if(is_future_packet)
		{
			/*con->PrintInfo();
			dout_con<<"Buffering reliable packet (seqnum="
					<<seqnum<<")"<<std::endl;*/
			
			// This one comes later, buffer it.
			// Actually we have to make a packet to buffer one.
			// Well, we have all the ingredients, so just do it.
			BufferedPacket packet = makePacket(
					con->GetPeer(peer_id)->address,
					packetdata,
					con->GetProtocolID(),
					peer_id,
					channelnum);
			try{
				incoming_reliables.insert(packet);
				
				/*con->PrintInfo();
				dout_con<<"INCOMING: ";
				incoming_reliables.print();
				dout_con<<std::endl;*/
			}
			catch(AlreadyExistsException &e)
			{
			}

			throw ProcessedSilentlyException("Buffered future reliable packet");
		}
		//else if(seqnum_higher(next_incoming_seqnum, seqnum))
		else if(is_old_packet)
		{
			// An old packet, dump it
			throw InvalidIncomingDataException("Got an old reliable packet");
		}

		next_incoming_seqnum++;

		// Get out the inside packet and re-process it
		SharedBuffer<u8> payload(packetdata.getSize() - RELIABLE_HEADER_SIZE);
		memcpy(*payload, &packetdata[RELIABLE_HEADER_SIZE], payload.getSize());

		return ProcessPacket(payload, con, peer_id, channelnum, true);
	}
	else
	{
		con->PrintInfo();
		dout_con<<"Got invalid type="<<((int)type&0xff)<<std::endl;
		throw InvalidIncomingDataException("Invalid packet type");
	}
	
	// We should never get here.
	// If you get here, add an exception or a return to some of the
	// above conditionals.
	assert(0);
	throw BaseException("Error in Channel::ProcessPacket()");
}

SharedBuffer<u8> Channel::CheckIncomingBuffers(Connection *con,
		u16 &peer_id)
{
	u16 firstseqnum = 0;
	// Clear old packets from start of buffer
	try{
	for(;;){
		firstseqnum = incoming_reliables.getFirstSeqnum();
		if(seqnum_higher(next_incoming_seqnum, firstseqnum))
			incoming_reliables.popFirst();
		else
			break;
	}
	// This happens if all packets are old
	}catch(con::NotFoundException)
	{}
	
	if(incoming_reliables.empty() == false)
	{
		if(firstseqnum == next_incoming_seqnum)
		{
			BufferedPacket p = incoming_reliables.popFirst();
			
			peer_id = readPeerId(*p.data);
			u8 channelnum = readChannel(*p.data);
			u16 seqnum = readU16(&p.data[BASE_HEADER_SIZE+1]);

			con->PrintInfo();
			dout_con<<"UNBUFFERING TYPE_RELIABLE"
					<<" seqnum="<<seqnum
					<<" peer_id="<<peer_id
					<<" channel="<<((int)channelnum&0xff)
					<<std::endl;

			next_incoming_seqnum++;
			
			u32 headers_size = BASE_HEADER_SIZE + RELIABLE_HEADER_SIZE;
			// Get out the inside packet and re-process it
			SharedBuffer<u8> payload(p.data.getSize() - headers_size);
			memcpy(*payload, &p.data[headers_size], payload.getSize());

			return ProcessPacket(payload, con, peer_id, channelnum, true);
		}
	}
		
	throw NoIncomingDataException("No relevant data in buffers");
}

SharedBuffer<u8> Connection::GetFromBuffers(u16 &peer_id)
{
	core::map<u16, Peer*>::Iterator j;
	j = m_peers.getIterator();
	for(; j.atEnd() == false; j++)
	{
		Peer *peer = j.getNode()->getValue();
		for(u16 i=0; i<CHANNEL_COUNT; i++)
		{
			Channel *channel = &peer->channels[i];
			try{
				SharedBuffer<u8> resultdata = channel->CheckIncomingBuffers
						(this, peer_id);

				return resultdata;
			}
			catch(NoIncomingDataException &e)
			{
			}
			catch(InvalidIncomingDataException &e)
			{
			}
			catch(ProcessedSilentlyException &e)
			{
			}
		}
	}
	throw NoIncomingDataException("No relevant data in buffers");
}

u32 Connection::Receive(u16 &peer_id, u8 *data, u32 datasize)
{
	/*
		Receive a packet from the network
	*/
	
	// TODO: We can not know how many layers of header there are.
	// For now, just assume there are no other than the base headers.
	u32 packet_maxsize = datasize + BASE_HEADER_SIZE;
	Buffer<u8> packetdata(packet_maxsize);
	
	for(;;)
	{
	try
	{
		/*
			Check if some buffer has relevant data
		*/
		try{
			SharedBuffer<u8> resultdata = GetFromBuffers(peer_id);

			if(datasize < resultdata.getSize())
				throw InvalidIncomingDataException
						("Buffer too small for received data");
				
			memcpy(data, *resultdata, resultdata.getSize());
			return resultdata.getSize();
		}
		catch(NoIncomingDataException &e)
		{
		}
	
		Address sender;

		s32 received_size = m_socket.Receive(sender, *packetdata, packet_maxsize);

		if(received_size < 0)
			throw NoIncomingDataException("No incoming data");
		if(received_size < BASE_HEADER_SIZE)
			throw InvalidIncomingDataException("No full header received");
		if(readU32(&packetdata[0]) != m_protocol_id)
			throw InvalidIncomingDataException("Invalid protocol id");
		
		peer_id = readPeerId(*packetdata);
		u8 channelnum = readChannel(*packetdata);
		if(channelnum > CHANNEL_COUNT-1){
			PrintInfo();
			dout_con<<"Receive(): Invalid channel "<<channelnum<<std::endl;
			throw InvalidIncomingDataException("Channel doesn't exist");
		}

		if(peer_id == PEER_ID_NEW)
		{
			/*
				Somebody is trying to send stuff to us with no peer id.
				
				Check if the same address and port was added to our peer
				list before.
				Allow only entries that have has_sent_with_id==false.
			*/

			core::map<u16, Peer*>::Iterator j;
			j = m_peers.getIterator();
			for(; j.atEnd() == false; j++)
			{
				Peer *peer = j.getNode()->getValue();
				if(peer->has_sent_with_id)
					continue;
				if(peer->address == sender)
					break;
			}
			
			/*
				If no peer was found with the same address and port,
				we shall assume it is a new peer and create an entry.
			*/
			if(j.atEnd())
			{
				// Pass on to adding the peer
			}
			// Else: A peer was found.
			else
			{
				Peer *peer = j.getNode()->getValue();
				peer_id = peer->id;
				PrintInfo();
				dout_con<<"WARNING: Assuming unknown peer to be "
						<<"peer_id="<<peer_id<<std::endl;
			}
		}
		
		/*
			The peer was not found in our lists. Add it.
		*/
		if(peer_id == PEER_ID_NEW)
		{
			// Somebody wants to make a new connection

			// Get a unique peer id (2 or higher)
			u16 peer_id_new = 2;
			core::map<u16, Peer*>::Iterator j;
			j = m_peers.getIterator();
			for(; j.atEnd() == false; j++)
			{
				Peer *peer = j.getNode()->getValue();
				if(peer_id_new <= peer->id)
					peer_id_new = peer->id + 1;
			}

			PrintInfo();
			dout_con<<"Receive(): Got a packet with peer_id=PEER_ID_NEW,"
					" giving peer_id="<<peer_id_new<<std::endl;

			// Create a peer
			Peer *peer = new Peer();
			peer->address = sender;
			peer->id = peer_id_new;
			m_peers.insert(peer->id, peer);
			
			// Create CONTROL packet to tell the peer id to the new peer.
			SharedBuffer<u8> reply(4);
			writeU8(&reply[0], TYPE_CONTROL);
			writeU8(&reply[1], CONTROLTYPE_SET_PEER_ID);
			writeU16(&reply[2], peer_id_new);
			SendAsPacket(peer_id_new, 0, reply, true);
			
			// We're now talking to a valid peer_id
			peer_id = peer_id_new;

			// Go on and process whatever it sent
		}

		core::map<u16, Peer*>::Node *node = m_peers.find(peer_id);

		if(node == NULL){
			// Peer not found
			PrintInfo();
			dout_con<<"Receive(): Peer not found"<<std::endl;
			throw InvalidIncomingDataException("Peer not found (possible timeout)");
		}

		Peer *peer = node->getValue();

		//TODO: Validate peer address
		
		peer->timeout_counter = 0.0;

		Channel *channel = &(peer->channels[channelnum]);
		
		// Throw the received packet to channel->processPacket()

		// Make a new SharedBuffer from the data without the base headers
		SharedBuffer<u8> strippeddata(received_size - BASE_HEADER_SIZE);
		memcpy(*strippeddata, &packetdata[BASE_HEADER_SIZE],
				strippeddata.getSize());
		
		try{
			// Process it (the result is some data with no headers made by us)
			SharedBuffer<u8> resultdata = channel->ProcessPacket
					(strippeddata, this, peer_id, channelnum);
			
			PrintInfo();
			dout_con<<"ProcessPacket returned data of size "
					<<resultdata.getSize()<<std::endl;
			
			if(datasize < resultdata.getSize())
				throw InvalidIncomingDataException
						("Buffer too small for received data");
			
			memcpy(data, *resultdata, resultdata.getSize());
			return resultdata.getSize();
		}
		catch(ProcessedSilentlyException &e)
		{
			// If there is more data, receive again
			if(m_socket.WaitData(0) == true)
				continue;
		}
		throw NoIncomingDataException("No incoming data (2)");
	} // try
	catch(InvalidIncomingDataException &e)
	{
		// If there is more data, receive again
		if(m_socket.WaitData(0) == true)
			continue;
	}
	} // for
}

void Connection::SendToAll(u8 channelnum, SharedBuffer<u8> data, bool reliable)
{
	core::map<u16, Peer*>::Iterator j;
	j = m_peers.getIterator();
	for(; j.atEnd() == false; j++)
	{
		Peer *peer = j.getNode()->getValue();
		Send(peer->id, channelnum, data, reliable);
	}
}

void Connection::Send(u16 peer_id, u8 channelnum,
		SharedBuffer<u8> data, bool reliable)
{
	assert(channelnum < CHANNEL_COUNT);

	Peer *peer = GetPeer(peer_id);
	Channel *channel = &(peer->channels[channelnum]);

	u32 chunksize_max = m_max_packet_size - BASE_HEADER_SIZE;
	if(reliable)
		chunksize_max -= RELIABLE_HEADER_SIZE;

	core::list<SharedBuffer<u8> > originals;
	originals = makeAutoSplitPacket(data, chunksize_max,
			channel->next_outgoing_split_seqnum);
	
	core::list<SharedBuffer<u8> >::Iterator i;
	i = originals.begin();
	for(; i != originals.end(); i++)
	{
		SharedBuffer<u8> original = *i;
		
		SendAsPacket(peer_id, channelnum, original, reliable);
	}
}

void Connection::SendAsPacket(u16 peer_id, u8 channelnum,
		SharedBuffer<u8> data, bool reliable)
{
	Peer *peer = GetPeer(peer_id);
	Channel *channel = &(peer->channels[channelnum]);

	if(reliable)
	{
		u16 seqnum = channel->next_outgoing_seqnum;
		channel->next_outgoing_seqnum++;

		SharedBuffer<u8> reliable = makeReliablePacket(data, seqnum);

		// Add base headers and make a packet
		BufferedPacket p = makePacket(peer->address, reliable,
				m_protocol_id, m_peer_id, channelnum);
		
		try{
			// Buffer the packet
			channel->outgoing_reliables.insert(p);
		}
		catch(AlreadyExistsException &e)
		{
			PrintInfo();
			dout_con<<"WARNING: Going to send a reliable packet "
					"seqnum="<<seqnum<<" that is already "
					"in outgoing buffer"<<std::endl;
			//assert(0);
		}
		
		// Send the packet
		RawSend(p);
	}
	else
	{
		// Add base headers and make a packet
		BufferedPacket p = makePacket(peer->address, data,
				m_protocol_id, m_peer_id, channelnum);

		// Send the packet
		RawSend(p);
	}
}

void Connection::RawSend(const BufferedPacket &packet)
{
	m_socket.Send(packet.address, *packet.data, packet.data.getSize());
}

void Connection::RunTimeouts(float dtime)
{
	core::list<u16> timeouted_peers;
	core::map<u16, Peer*>::Iterator j;
	j = m_peers.getIterator();
	for(; j.atEnd() == false; j++)
	{
		Peer *peer = j.getNode()->getValue();

		// Check peer timeout
		peer->timeout_counter += dtime;
		// TODO: Get the constant timeout from somewhere else
		if(peer->timeout_counter > 30.0)
		{
			PrintInfo();
			dout_con<<"RunTimeouts(): Peer "<<peer->id
					<<" has timeouted."<<std::endl;
			// Add peer to the list
			timeouted_peers.push_back(peer->id);
			// Don't bother going through the buffers of this one
			continue;
		}

		peer->ping_timer += dtime;
		if(peer->ping_timer >= 5.0)
		{
			// Create and send PING packet
			SharedBuffer<u8> data(2);
			writeU8(&data[0], TYPE_CONTROL);
			writeU8(&data[1], CONTROLTYPE_PING);
			SendAsPacket(peer->id, 0, data, true);

			peer->ping_timer = 0.0;
		}

		float resend_timeout = peer->resend_timeout;
		for(u16 i=0; i<CHANNEL_COUNT; i++)
		{
			Channel *channel = &peer->channels[i];

			// Re-send timed out outgoing reliables

			channel->outgoing_reliables.incrementTimeouts(dtime);

			core::list<BufferedPacket> timed_outs
					= channel->outgoing_reliables.getTimedOuts(resend_timeout);

			channel->outgoing_reliables.resetTimedOuts(resend_timeout);

			core::list<BufferedPacket>::Iterator j = timed_outs.begin();
			for(; j != timed_outs.end(); j++)
			{
				u16 peer_id = readPeerId(*(j->data));
				u8 channel = readChannel(*(j->data));
				u16 seqnum = readU16(&(j->data[BASE_HEADER_SIZE+1]));
				PrintInfo();
				dout_con<<"RE-SENDING timed-out RELIABLE: "
						<<"peer_id="<<peer_id
						<<", channel="<<((int)channel&0xff)
						<<", seqnum="<<seqnum
						<<std::endl;
				RawSend(*j);
			}
			
			// Remove timed out incomplete unreliable split packets

			channel->incoming_splits.removeUnreliableTimedOuts(dtime, 5.0);
		}
	}

	// Remove timeouted peers
	core::list<u16>::Iterator i = timeouted_peers.begin();
	for(; i != timeouted_peers.end(); i++)
	{
		PrintInfo();
		dout_con<<"RunTimeouts(): Removing peer "<<(*i)<<std::endl;
		m_peers.remove(*i);
	}
}

Peer* Connection::GetPeer(u16 peer_id)
{
	core::map<u16, Peer*>::Node *node = m_peers.find(peer_id);

	if(node == NULL){
		// Peer not found
		throw NotFoundException("Peer not found (possible timeout)");
	}

	// Error checking
	assert(node->getValue()->id == peer_id);

	return node->getValue();
}

void Connection::PrintInfo()
{
	/*for(u16 i=0; i<m_indentation; i++)
		dout_con<<"  ";
	dout_con<<"Connection(h="<<m_socket.GetHandle()<<", id="
			<<m_peer_id<<"): ";*/
	dout_con<<m_socket.GetHandle();
	dout_con<<" ";
	dout_con<<"con "<<m_peer_id<<": ";
	for(s16 i=0; i<(s16)m_indentation-1; i++)
		dout_con<<"  ";
}

} // namespace