X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=KernelLand%2FModules%2FIPStack%2Ftcp.c;h=86ff8190e9afa35c29d796b1a5b2345752a23802;hb=12c9ce3978373fcadb7015e75cce56f6e181488d;hp=f1eee656d7b0a7633040305bb1605a51eafd6f51;hpb=da91486679507cd3dc4a139318e05ce04e151145;p=tpg%2Facess2.git

diff --git a/KernelLand/Modules/IPStack/tcp.c b/KernelLand/Modules/IPStack/tcp.c
index f1eee656..86ff8190 100644
--- a/KernelLand/Modules/IPStack/tcp.c
+++ b/KernelLand/Modules/IPStack/tcp.c
@@ -8,10 +8,8 @@
 #include "ipv6.h"
 #include "tcp.h"
 
-#define USE_SELECT	1
 #define HEXDUMP_INCOMING	0
 #define HEXDUMP_OUTGOING	0
-#define	CACHE_FUTURE_PACKETS_IN_BYTES	1	// Use a ring buffer to cache out of order packets
 
 #define TCP_MIN_DYNPORT	0xC000
 #define TCP_MAX_HALFOPEN	1024	// Should be enough
@@ -22,28 +20,34 @@
 #define TCP_DACK_THRESHOLD	4096
 #define TCP_DACK_TIMEOUT	500
 
+#define TCP_DEBUG	0	// Set to non-0 to enable TCP packet logging
+
 // === PROTOTYPES ===
 void	TCP_Initialise(void);
 void	TCP_StartConnection(tTCPConnection *Conn);
 void	TCP_SendPacket(tTCPConnection *Conn, tTCPHeader *Header, size_t DataLen, const void *Data);
+void	TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Header, size_t Length, const void *Data);
 void	TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer);
 void	TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Header, int Length);
 int	TCP_INT_AppendRecieved(tTCPConnection *Connection, const void *Data, size_t Length);
 void	TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection);
-void	TCP_INT_SendACK(tTCPConnection *Connection);
+void	TCP_int_SendDelayedACK(void *ConnPtr);
+void	TCP_INT_SendACK(tTCPConnection *Connection, const char *Reason);
 Uint16	TCP_GetUnusedPort();
  int	TCP_AllocatePort(Uint16 Port);
  int	TCP_DeallocatePort(Uint16 Port);
+tTCPConnection	*TCP_int_CreateConnection(tInterface *Interface, enum eTCPConnectionState State);
+void	TCP_int_FreeTCB(tTCPConnection *Connection);
 // --- Server
 tVFS_Node	*TCP_Server_Init(tInterface *Interface);
  int	TCP_Server_ReadDir(tVFS_Node *Node, int Pos, char Name[FILENAME_MAX]);
-tVFS_Node	*TCP_Server_FindDir(tVFS_Node *Node, const char *Name);
+tVFS_Node	*TCP_Server_FindDir(tVFS_Node *Node, const char *Name, Uint Flags);
  int	TCP_Server_IOCtl(tVFS_Node *Node, int ID, void *Data);
 void	TCP_Server_Close(tVFS_Node *Node);
 // --- Client
 tVFS_Node	*TCP_Client_Init(tInterface *Interface);
-size_t	TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer);
-size_t	TCP_Client_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer);
+size_t	TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags);
+size_t	TCP_Client_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags);
  int	TCP_Client_IOCtl(tVFS_Node *Node, int ID, void *Data);
 void	TCP_Client_Close(tVFS_Node *Node);
 // --- Helpers
@@ -84,7 +88,7 @@ Uint32	gaTCP_PortBitmap[0x800];
  */
 void TCP_Initialise(void)
 {
-	giTCP_NextOutPort += rand()%32;
+	giTCP_NextOutPort += rand()%128;
 	IPStack_AddFile(&gTCP_ServerFile);
 	IPStack_AddFile(&gTCP_ClientFile);
 	IPv4_RegisterCallback(IP4PROT_TCP, TCP_GetPacket);
@@ -98,6 +102,11 @@ void TCP_Initialise(void)
  * \param Data	Packet data (cast as a TCP Header)
  */
 void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, const void *Data )
+{
+	TCP_int_SendPacket(Conn->Interface, &Conn->RemoteIP, Header, Length, Data);
+}
+
+void TCP_int_SendPacket(tInterface *Interface, const void *Dest, tTCPHeader *Header, size_t Length, const void *Data )
 {
 	tIPStackBuffer	*buffer;
 	Uint16	checksum[3];
@@ -109,8 +118,8 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
 	IPStack_Buffer_AppendSubBuffer(buffer, sizeof(*Header), 0, Header, NULL, NULL);
 
 	LOG("Sending %i+%i to %s:%i", sizeof(*Header), Length,
-		IPStack_PrintAddress(Conn->Interface->Type, &Conn->RemoteIP),
-		Conn->RemotePort
+		IPStack_PrintAddress(Interface->Type, Dest),
+		ntohs(Header->RemotePort)
 		);
 
 	Header->Checksum = 0;
@@ -119,38 +128,59 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
 	
 	// TODO: Fragment packet
 	
-	switch( Conn->Interface->Type )
+	switch( Interface->Type )
 	{
 	case 4:
 		// Get IPv4 pseudo-header checksum
 		{
 			Uint32	buf[3];
-			buf[0] = ((tIPv4*)Conn->Interface->Address)->L;
-			buf[1] = Conn->RemoteIP.v4.L;
-			buf[2] = (htons(packlen)<<16) | (6<<8) | 0;
+			buf[0] = ((tIPv4*)Interface->Address)->L;
+			buf[1] = ((tIPv4*)Dest)->L;
+			buf[2] = htonl( (packlen) | (IP4PROT_TCP<<16) | (0<<24) );
 			checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );	// Partial checksum
 		}
 		// - Combine checksums
 		Header->Checksum = htons( IPv4_Checksum(checksum, sizeof(checksum)) );
-		IPv4_SendPacket(Conn->Interface, Conn->RemoteIP.v4, IP4PROT_TCP, 0, buffer);
+		IPv4_SendPacket(Interface, *(tIPv4*)Dest, IP4PROT_TCP, 0, buffer);
 		break;
 		
 	case 6:
 		// Append IPv6 Pseudo Header
 		{
 			Uint32	buf[4+4+1+1];
-			memcpy(buf, Conn->Interface->Address, 16);
-			memcpy(&buf[4], &Conn->RemoteIP, 16);
+			memcpy(buf, Interface->Address, 16);
+			memcpy(&buf[4], Dest, 16);
 			buf[8] = htonl(packlen);
-			buf[9] = htonl(6);
+			buf[9] = htonl(IP4PROT_TCP);
 			checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );	// Partial checksum
 		}
 		Header->Checksum = htons( IPv4_Checksum(checksum, sizeof(checksum)) );	// Combine the two
-		IPv6_SendPacket(Conn->Interface, Conn->RemoteIP.v6, IP4PROT_TCP, Length, Data);
+		IPv6_SendPacket(Interface, *(tIPv6*)Dest, IP4PROT_TCP, buffer);
 		break;
 	}
 }
 
+void TCP_int_SendRSTTo(tInterface *Interface, void *Address, size_t Length, const tTCPHeader *Header)
+{
+	tTCPHeader	out_hdr = {0};
+	
+	out_hdr.DataOffset = (sizeof(out_hdr)/4) << 4;
+	out_hdr.DestPort = Header->SourcePort;
+	out_hdr.SourcePort = Header->DestPort;
+
+	size_t	data_len = Length - (Header->DataOffset>>4)*4;
+	out_hdr.AcknowlegementNumber = htonl( ntohl(Header->SequenceNumber) + data_len );
+	if( Header->Flags & TCP_FLAG_ACK ) {
+		out_hdr.Flags = TCP_FLAG_RST;
+		out_hdr.SequenceNumber = Header->AcknowlegementNumber;
+	}
+	else {
+		out_hdr.Flags = TCP_FLAG_RST|TCP_FLAG_ACK;
+		out_hdr.SequenceNumber = 0;
+	}
+	TCP_int_SendPacket(Interface, Address, &out_hdr, 0, NULL);
+}
+
 /**
  * \brief Handles a packet from the IP Layer
  * \param Interface	Interface the packet arrived from
@@ -161,9 +191,8 @@ void TCP_SendPacket( tTCPConnection *Conn, tTCPHeader *Header, size_t Length, co
 void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
 {
 	tTCPHeader	*hdr = Buffer;
-	tTCPListener	*srv;
-	tTCPConnection	*conn;
 
+	#if TCP_DEBUG
 	Log_Log("TCP", "TCP_GetPacket: <Local>:%i from [%s]:%i, Flags = %s%s%s%s%s%s%s%s",
 		ntohs(hdr->DestPort),
 		IPStack_PrintAddress(Interface->Type, Address),
@@ -177,6 +206,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 		(hdr->Flags & TCP_FLAG_SYN) ? "SYN " : "",
 		(hdr->Flags & TCP_FLAG_FIN) ? "FIN " : ""
 		);
+	#endif
 
 	if( Length > (hdr->DataOffset >> 4)*4 )
 	{
@@ -191,7 +221,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 	}
 
 	// Check Servers
-	for( srv = gTCP_Listeners; srv; srv = srv->Next )
+	for( tTCPListener *srv = gTCP_Listeners; srv; srv = srv->Next )
 	{
 		// Check if the server is active
 		if(srv->Port == 0)	continue;
@@ -202,7 +232,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 		
 		Log_Log("TCP", "TCP_GetPacket: Matches server %p", srv);
 		// Is this in an established connection?
-		for( conn = srv->Connections; conn; conn = conn->Next )
+		for( tTCPConnection *conn = srv->Connections; conn; conn = conn->Next )
 		{
 			// Check that it is coming in on the same interface
 			if(conn->Interface != Interface)	continue;
@@ -227,38 +257,40 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 			return;
 		}
 
-		Log_Log("TCP", "TCP_GetPacket: Opening Connection");
-		// Open a new connection (well, check that it's a SYN)
-		if(hdr->Flags != TCP_FLAG_SYN) {
-			Log_Log("TCP", "TCP_GetPacket: Packet is not a SYN");
+		
+		if( hdr->Flags & TCP_FLAG_RST ) {
+			LOG("RST, ignore");
+			return ;
+		}
+		else if( hdr->Flags & TCP_FLAG_ACK ) {
+			LOG("ACK, send RST");
+			TCP_int_SendRSTTo(Interface, Address, Length, hdr);
+			return ;
+		}
+		else if( !(hdr->Flags & TCP_FLAG_SYN) ) {
+			LOG("Other, ignore");
 			return ;
 		}
+		Log_Log("TCP", "TCP_GetPacket: Opening Connection");
 		
 		// TODO: Check for halfopen max
 		
-		conn = calloc(1, sizeof(tTCPConnection));
-		conn->State = TCP_ST_SYN_RCVD;
+		tTCPConnection *conn = TCP_int_CreateConnection(Interface, TCP_ST_SYN_RCVD);
 		conn->LocalPort = srv->Port;
 		conn->RemotePort = ntohs(hdr->SourcePort);
-		conn->Interface = Interface;
 		
 		switch(Interface->Type)
 		{
 		case 4:	conn->RemoteIP.v4 = *(tIPv4*)Address;	break;
 		case 6:	conn->RemoteIP.v6 = *(tIPv6*)Address;	break;
+		default:	ASSERTC(Interface->Type,==,4);	return;
 		}
 		
-		conn->RecievedBuffer = RingBuffer_Create( TCP_RECIEVE_BUFFER_SIZE );
-		
 		conn->NextSequenceRcv = ntohl( hdr->SequenceNumber ) + 1;
+		conn->HighestSequenceRcvd = conn->NextSequenceRcv;
 		conn->NextSequenceSend = rand();
 		
-		// Create node
-		conn->Node.NumACLs = 1;
-		conn->Node.ACLs = &gVFS_ACL_EveryoneRW;
-		conn->Node.ImplPtr = conn;
 		conn->Node.ImplInt = srv->NextID ++;
-		conn->Node.Type = &gTCP_ClientNodeType;	// TODO: Special type for the server end?
 		
 		// Hmm... Theoretically, this lock will never have to wait,
 		// as the interface is locked to the watching thread, and this
@@ -267,10 +299,16 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 		// Oh, wait, there is a case where a wildcard can be used
 		// (srv->Interface == NULL) so having the lock is a good idea
 		SHORTLOCK(&srv->lConnections);
-		if( !srv->Connections )
-			srv->Connections = conn;
-		else
+		conn->Server = srv;
+		conn->Prev = srv->ConnectionsTail;
+		if(srv->Connections) {
+			ASSERT(srv->ConnectionsTail);
 			srv->ConnectionsTail->Next = conn;
+		}
+		else {
+			ASSERT(!srv->ConnectionsTail);
+			srv->Connections = conn;
+		}
 		srv->ConnectionsTail = conn;
 		if(!srv->NewConnections)
 			srv->NewConnections = conn;
@@ -292,7 +330,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 
 	// Check Open Connections
 	{
-		for( conn = gTCP_OutbountCons; conn; conn = conn->Next )
+		for( tTCPConnection *conn = gTCP_OutbountCons; conn; conn = conn->Next )
 		{
 			// Check that it is coming in on the same interface
 			if(conn->Interface != Interface)	continue;
@@ -312,6 +350,11 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
 	}
 	
 	Log_Log("TCP", "TCP_GetPacket: No Match");
+	// If not a RST, send a RST
+	if( !(hdr->Flags & TCP_FLAG_RST) )
+	{
+		TCP_int_SendRSTTo(Interface, Address, Length, hdr);
+	}
 }
 
 /**
@@ -336,8 +379,12 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 	if(Header->Flags & TCP_FLAG_SYN) {
 		// TODO: What if the packet also has data?
 		if( Connection->LastACKSequence != Connection->NextSequenceRcv )
-			TCP_INT_SendACK(Connection);
+			TCP_INT_SendACK(Connection, "SYN");
 		Connection->NextSequenceRcv = ntohl(Header->SequenceNumber);
+		// TODO: Process HighestSequenceRcvd
+		// HACK!
+		if( Connection->HighestSequenceRcvd == 0 )
+			Connection->HighestSequenceRcvd = Connection->NextSequenceRcv;
 		Connection->LastACKSequence = Connection->NextSequenceRcv;
 	}
 	
@@ -350,7 +397,9 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 	// Get length of data
 	dataLen = Length - (Header->DataOffset>>4)*4;
 	LOG("dataLen = %i", dataLen);
-//	Log_Debug("TCP", "State %i, dataLen = %x", Connection->State, dataLen);
+	#if TCP_DEBUG
+	Log_Debug("TCP", "State %i, dataLen = %x", Connection->State, dataLen);
+	#endif
 	
 	// 
 	// State Machine
@@ -367,15 +416,9 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 	case TCP_ST_SYN_SENT:
 		if( Header->Flags & TCP_FLAG_SYN )
 		{
+			if( Connection->HighestSequenceRcvd == Connection->NextSequenceRcv )
+				Connection->HighestSequenceRcvd ++;
 			Connection->NextSequenceRcv ++;
-			Header->DestPort = Header->SourcePort;
-			Header->SourcePort = htons(Connection->LocalPort);
-			Header->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
-			Header->SequenceNumber = htonl(Connection->NextSequenceSend);
-			Header->WindowSize = htons(TCP_WINDOW_SIZE);
-			Header->Flags = TCP_FLAG_ACK;
-			Header->DataOffset = (sizeof(tTCPHeader)/4) << 4;
-			TCP_SendPacket( Connection, Header, 0, NULL );
 			
 			if( Header->Flags & TCP_FLAG_ACK )
 			{	
@@ -388,6 +431,14 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 				Log_Log("TCP", "ACKing SYN");
 				Connection->State = TCP_ST_SYN_RCVD;
 			}
+			Header->DestPort = Header->SourcePort;
+			Header->SourcePort = htons(Connection->LocalPort);
+			Header->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
+			Header->SequenceNumber = htonl(Connection->NextSequenceSend);
+			Header->WindowSize = htons(TCP_WINDOW_SIZE);
+			Header->Flags = TCP_FLAG_ACK;
+			Header->DataOffset = (sizeof(tTCPHeader)/4) << 4;
+			TCP_SendPacket( Connection, Header, 0, NULL );
 		}
 		break;
 	
@@ -409,12 +460,11 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 		if( Header->Flags & TCP_FLAG_FIN ) {
 			Log_Log("TCP", "Conn %p closed, recieved FIN", Connection);
 			VFS_MarkError(&Connection->Node, 1);
+			Connection->NextSequenceRcv ++;
+			TCP_INT_SendACK(Connection, "FIN Received");
 			Connection->State = TCP_ST_CLOSE_WAIT;
-//			Header->Flags &= ~TCP_FLAG_FIN;
-			// CLOSE WAIT requires the client to close (or does it?)
-			#if 0
-			
-			#endif
+			// CLOSE WAIT requires the client to close
+			return ;
 		}
 	
 		// Check for an empty packet
@@ -424,14 +474,12 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 				Log_Log("TCP", "ACK only packet");
 				return ;
 			}
-			Connection->NextSequenceRcv ++;	// TODO: Is this right? (empty packet counts as one byte)
+			// TODO: Is this right? (empty packet counts as one byte)
+			if( Connection->HighestSequenceRcvd == Connection->NextSequenceRcv )
+				Connection->HighestSequenceRcvd ++;
+			Connection->NextSequenceRcv ++;
 			Log_Log("TCP", "Empty Packet, inc and ACK the current sequence number");
-			Header->DestPort = Header->SourcePort;
-			Header->SourcePort = htons(Connection->LocalPort);
-			Header->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
-			Header->SequenceNumber = htonl(Connection->NextSequenceSend);
-			Header->Flags |= TCP_FLAG_ACK;
-			TCP_SendPacket( Connection, Header, 0, NULL );
+			TCP_INT_SendACK(Connection, "Empty");
 			return ;
 		}
 		
@@ -442,7 +490,7 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 		
 		sequence_num = ntohl(Header->SequenceNumber);
 		
-		LOG("TCP", "0x%08x <= 0x%08x < 0x%08x",
+		LOG("0x%08x <= 0x%08x < 0x%08x",
 			Connection->NextSequenceRcv,
 			ntohl(Header->SequenceNumber),
 			Connection->NextSequenceRcv + TCP_WINDOW_SIZE
@@ -462,6 +510,8 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 				break;
 			}
 			LOG("0x%08x += %i", Connection->NextSequenceRcv, dataLen);
+			if( Connection->HighestSequenceRcvd == Connection->NextSequenceRcv )
+				Connection->HighestSequenceRcvd += dataLen;
 			Connection->NextSequenceRcv += dataLen;
 			
 			// TODO: This should be moved out of the watcher thread,
@@ -474,14 +524,14 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 			// - Only send an ACK if we've had a burst
 			if( Connection->NextSequenceRcv > (Uint32)(TCP_DACK_THRESHOLD + Connection->LastACKSequence) )
 			{
-				TCP_INT_SendACK(Connection);
+				TCP_INT_SendACK(Connection, "DACK Burst");
 				// - Extend TCP deferred ACK timer
 				Time_RemoveTimer(Connection->DeferredACKTimer);
 			}
 			// - Schedule the deferred ACK timer (if already scheduled, this is a NOP)
 			Time_ScheduleTimer(Connection->DeferredACKTimer, TCP_DACK_TIMEOUT);
 			#else
-			TCP_INT_SendACK(Connection);
+			TCP_INT_SendACK(Connection, "RX");
 			#endif
 		}
 		// Check if the packet is in window
@@ -491,10 +541,9 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 			Uint8	*dataptr = (Uint8*)Header + (Header->DataOffset>>4)*4;
 			#if CACHE_FUTURE_PACKETS_IN_BYTES
 			Uint32	index;
-			 int	i;
 			
 			index = sequence_num % TCP_WINDOW_SIZE;
-			for( i = 0; i < dataLen; i ++ )
+			for( int i = 0; i < dataLen; i ++ )
 			{
 				Connection->FuturePacketValidBytes[index/8] |= 1 << (index%8);
 				Connection->FuturePacketData[index] = dataptr[i];
@@ -554,7 +603,7 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 			Log_Log("TCP", "Fully out of sequence packet (0x%08x not between 0x%08x and 0x%08x), dropped",
 				sequence_num, Connection->NextSequenceRcv, Connection->NextSequenceRcv+TCP_WINDOW_SIZE);
 			// Spec says we should send an empty ACK with the current state
-			TCP_INT_SendACK(Connection);
+			TCP_INT_SendACK(Connection, "Bad Seq");
 		}
 		break;
 	
@@ -572,7 +621,7 @@ void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Head
 		{
 			Connection->State = TCP_ST_FINISHED;	// Connection completed
 			Log_Log("TCP", "LAST-ACK to CLOSED - Connection remote closed");
-			// TODO: Destrory the TCB
+			TCP_int_FreeTCB(Connection);
 		}
 		break;
 	
@@ -688,26 +737,30 @@ int TCP_INT_AppendRecieved(tTCPConnection *Connection, const void *Data, size_t
 void TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection)
 {
 	#if CACHE_FUTURE_PACKETS_IN_BYTES
-	 int	i, length = 0;
-	Uint32	index;
-	
 	// Calculate length of contiguous bytes
-	length = Connection->HighestSequenceRcvd - Connection->NextSequenceRcv;
-	index = Connection->NextSequenceRcv % TCP_WINDOW_SIZE;
-	for( i = 0; i < length; i ++ )
+	 int	length = Connection->HighestSequenceRcvd - Connection->NextSequenceRcv;
+	Uint32	index = Connection->NextSequenceRcv % TCP_WINDOW_SIZE;
+	LOG("length=%i, index=%i", length, index);
+	for( int i = 0; i < length; i ++ )
 	{
-		if( Connection->FuturePacketValidBytes[i / 8] == 0xFF ) {
-			i += 7;	index += 7;
-			continue;
-		}
-		else if( !(Connection->FuturePacketValidBytes[i / 8] & (1 << (i%8))) )
+		 int	bit = index % 8;
+		Uint8	bitfield_byte = Connection->FuturePacketValidBytes[index / 8];
+		if( (bitfield_byte & (1 << bit)) == 0 ) {
+			length = i;
 			break;
-		
-		index ++;
+		}
+
+		if( bitfield_byte == 0xFF ) {
+			 int	inc = 8 - bit;
+			i += inc - 1;
+			index += inc;
+		}
+		else {
+			index ++;
+		}
 		if(index > TCP_WINDOW_SIZE)
 			index -= TCP_WINDOW_SIZE;
 	}
-	length = i;
 	
 	index = Connection->NextSequenceRcv % TCP_WINDOW_SIZE;
 	
@@ -727,10 +780,10 @@ void TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection)
 	
 	// Mark (now saved) bytes as invalid
 	// - Align index
-	while(index % 8 && length)
+	while(index % 8 && length > 0)
 	{
 		Connection->FuturePacketData[index] = 0;
-		Connection->FuturePacketData[index/8] &= ~(1 << (index%8));
+		Connection->FuturePacketValidBytes[index/8] &= ~(1 << (index%8));
 		index ++;
 		if(index > TCP_WINDOW_SIZE)
 			index -= TCP_WINDOW_SIZE;
@@ -787,14 +840,21 @@ void TCP_INT_UpdateRecievedFromFuture(tTCPConnection *Connection)
 		SHORTREL( &Connection->lFuturePackets );
 		
 		// Looks like we found one
-		TCP_INT_AppendRecieved(Connection, pkt);
+		TCP_INT_AppendRecieved(Connection, pkt->Data, pkt->Length);
+		if( Connection->HighestSequenceRcvd == Connection->NextSequenceRcv )
+			Connection->HighestSequenceRcvd += pkt->Length;
 		Connection->NextSequenceRcv += pkt->Length;
 		free(pkt);
 	}
 	#endif
 }
 
-void TCP_INT_SendACK(tTCPConnection *Connection)
+void TCP_int_SendDelayedACK(void *ConnPtr)
+{
+	TCP_INT_SendACK(ConnPtr, "DACK Timeout");
+}
+
+void TCP_INT_SendACK(tTCPConnection *Connection, const char *Reason)
 {
 	tTCPHeader	hdr;
 	// ACK Packet
@@ -807,7 +867,7 @@ void TCP_INT_SendACK(tTCPConnection *Connection)
 	hdr.Flags = TCP_FLAG_ACK;	// TODO: Determine if SYN is wanted too
 	hdr.Checksum = 0;	// TODO: Checksum
 	hdr.UrgentPointer = 0;
-	Log_Debug("TCP", "Sending ACK for 0x%08x", Connection->NextSequenceRcv);
+	Log_Debug("TCP", "Sending ACK for 0x%08x (%s)", Connection->NextSequenceRcv, Reason);
 	TCP_SendPacket( Connection, &hdr, 0, NULL );
 	//Connection->NextSequenceSend ++;
 	Connection->LastACKSequence = Connection->NextSequenceRcv;
@@ -870,6 +930,79 @@ int TCP_DeallocatePort(Uint16 Port)
 	return 1;
 }
 
+tTCPConnection *TCP_int_CreateConnection(tInterface *Interface, enum eTCPConnectionState State)
+{
+	tTCPConnection	*conn = calloc( sizeof(tTCPConnection) + TCP_WINDOW_SIZE + TCP_WINDOW_SIZE/8, 1 );
+
+	conn->State = State;
+	conn->Interface = Interface;
+	conn->LocalPort = -1;
+	conn->RemotePort = -1;
+
+	conn->Node.ReferenceCount = 1;
+	conn->Node.ImplPtr = conn;
+	conn->Node.NumACLs = 1;
+	conn->Node.ACLs = &gVFS_ACL_EveryoneRW;
+	conn->Node.Type = &gTCP_ClientNodeType;
+	conn->Node.BufferFull = 1;	// Cleared when connection opens
+
+	conn->RecievedBuffer = RingBuffer_Create( TCP_RECIEVE_BUFFER_SIZE );
+	#if 0
+	conn->SentBuffer = RingBuffer_Create( TCP_SEND_BUFFER_SIZE );
+	Semaphore_Init(conn->SentBufferSpace, 0, TCP_SEND_BUFFER_SIZE, "TCP SentBuffer", conn->Name);
+	#endif
+	
+	#if CACHE_FUTURE_PACKETS_IN_BYTES
+	// Future recieved data (ahead of the expected sequence number)
+	conn->FuturePacketData = (Uint8*)conn + sizeof(tTCPConnection);
+	conn->FuturePacketValidBytes = conn->FuturePacketData + TCP_WINDOW_SIZE;
+	#endif
+
+	conn->DeferredACKTimer = Time_AllocateTimer( TCP_int_SendDelayedACK, conn);
+	return conn;
+}
+
+void TCP_int_FreeTCB(tTCPConnection *Connection)
+{
+	ASSERTC(Connection->State, ==, TCP_ST_FINISHED);
+	ASSERTC(Connection->Node.ReferenceCount, ==, 0);
+
+	if( Connection->Server )
+	{
+		tTCPListener	*srv = Connection->Server;
+		SHORTLOCK(&srv->lConnections);
+		if(Connection->Prev)
+			Connection->Prev->Next = Connection->Next;
+		else
+			srv->Connections = Connection->Next;
+		if(Connection->Next)
+			Connection->Next->Prev = Connection->Prev;
+		else {
+			ASSERT(srv->ConnectionsTail == Connection);
+			srv->ConnectionsTail = Connection->Prev;
+		}
+		SHORTREL(&srv->lConnections);
+	}
+	else
+	{
+		SHORTLOCK(&glTCP_OutbountCons);
+		if(Connection->Prev)
+			Connection->Prev->Next = Connection->Next;
+		else
+			gTCP_OutbountCons = Connection->Next;
+		if(Connection->Next)
+			Connection->Next->Prev = Connection->Prev;
+		else
+			;
+		SHORTREL(&glTCP_OutbountCons);
+	}
+
+	RingBuffer_Free(Connection->RecievedBuffer);
+	Time_FreeTimer(Connection->DeferredACKTimer);
+	// TODO: Force VFS to close handles? (they should all be closed);
+	free(Connection);
+}
+
 // --- Server
 tVFS_Node *TCP_Server_Init(tInterface *Interface)
 {
@@ -947,7 +1080,7 @@ int TCP_Server_ReadDir(tVFS_Node *Node, int Pos, char Dest[FILENAME_MAX])
  * \param Node	Server node
  * \param Name	Hexadecimal ID of the node
  */
-tVFS_Node *TCP_Server_FindDir(tVFS_Node *Node, const char *Name)
+tVFS_Node *TCP_Server_FindDir(tVFS_Node *Node, const char *Name, Uint Flags)
 {
 	tTCPConnection	*conn;
 	tTCPListener	*srv = Node->ImplPtr;
@@ -1062,35 +1195,13 @@ void TCP_Server_Close(tVFS_Node *Node)
  */
 tVFS_Node *TCP_Client_Init(tInterface *Interface)
 {
-	tTCPConnection	*conn = calloc( sizeof(tTCPConnection) + TCP_WINDOW_SIZE + TCP_WINDOW_SIZE/8, 1 );
-
-	conn->State = TCP_ST_CLOSED;
-	conn->Interface = Interface;
-	conn->LocalPort = -1;
-	conn->RemotePort = -1;
-
-	conn->Node.ImplPtr = conn;
-	conn->Node.NumACLs = 1;
-	conn->Node.ACLs = &gVFS_ACL_EveryoneRW;
-	conn->Node.Type = &gTCP_ClientNodeType;
-	conn->Node.BufferFull = 1;	// Cleared when connection opens
-
-	conn->RecievedBuffer = RingBuffer_Create( TCP_RECIEVE_BUFFER_SIZE );
-	#if 0
-	conn->SentBuffer = RingBuffer_Create( TCP_SEND_BUFFER_SIZE );
-	Semaphore_Init(conn->SentBufferSpace, 0, TCP_SEND_BUFFER_SIZE, "TCP SentBuffer", conn->Name);
-	#endif
-	
-	#if CACHE_FUTURE_PACKETS_IN_BYTES
-	// Future recieved data (ahead of the expected sequence number)
-	conn->FuturePacketData = (Uint8*)conn + sizeof(tTCPConnection);
-	conn->FuturePacketValidBytes = conn->FuturePacketData + TCP_WINDOW_SIZE;
-	#endif
-
-	conn->DeferredACKTimer = Time_AllocateTimer( (void(*)(void*)) TCP_INT_SendACK, conn);
+	tTCPConnection	*conn = TCP_int_CreateConnection(Interface, TCP_ST_CLOSED);
 
 	SHORTLOCK(&glTCP_OutbountCons);
+	conn->Server = NULL;
+	conn->Prev = NULL;
 	conn->Next = gTCP_OutbountCons;
+	gTCP_OutbountCons->Prev = conn;
 	gTCP_OutbountCons = conn;
 	SHORTREL(&glTCP_OutbountCons);
 
@@ -1102,7 +1213,7 @@ tVFS_Node *TCP_Client_Init(tInterface *Interface)
  * \note If \a Length is smaller than the size of the packet, the rest
  *       of the packet's data will be discarded.
  */
-size_t TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer)
+size_t TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffer, Uint Flags)
 {
 	tTCPConnection	*conn = Node->ImplPtr;
 	size_t	len;
@@ -1120,6 +1231,7 @@ size_t TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffe
 		
 		if( len == 0 ) {
 			VFS_MarkAvaliable(Node, 0);
+			errno = 0;
 			LEAVE('i', -1);
 			return -1;
 		}
@@ -1129,7 +1241,17 @@ size_t TCP_Client_Read(tVFS_Node *Node, off_t Offset, size_t Length, void *Buffe
 	}
 	
 	// Wait
-	VFS_SelectNode(Node, VFS_SELECT_READ|VFS_SELECT_ERROR, NULL, "TCP_Client_Read");
+	{
+		tTime	*timeout = NULL;
+		tTime	timeout_zero = 0;
+		if( Flags & VFS_IOFLAG_NOBLOCK )
+			timeout = &timeout_zero;
+		if( !VFS_SelectNode(Node, VFS_SELECT_READ|VFS_SELECT_ERROR, timeout, "TCP_Client_Read") ) {
+			errno = EWOULDBLOCK;
+			LEAVE('i', -1);
+			return -1;
+		}
+	}
 	
 	// Lock list and read as much as possible (up to `Length`)
 	Mutex_Acquire( &conn->lRecievedPackets );
@@ -1154,6 +1276,9 @@ void TCP_INT_SendDataPacket(tTCPConnection *Connection, size_t Length, const voi
 {
 	char	buf[sizeof(tTCPHeader)+Length];
 	tTCPHeader	*packet = (void*)buf;
+
+	// - Stop Delayed ACK timer (as this data packet ACKs)
+	Time_RemoveTimer(Connection->DeferredACKTimer);
 	
 	packet->SourcePort = htons(Connection->LocalPort);
 	packet->DestPort = htons(Connection->RemotePort);
@@ -1163,6 +1288,7 @@ void TCP_INT_SendDataPacket(tTCPConnection *Connection, size_t Length, const voi
 	packet->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
 	packet->SequenceNumber = htonl(Connection->NextSequenceSend);
 	packet->Flags = TCP_FLAG_PSH|TCP_FLAG_ACK;	// Hey, ACK if you can!
+	packet->UrgentPointer = 0;
 	
 	memcpy(packet->Options, Data, Length);
 	
@@ -1179,7 +1305,7 @@ void TCP_INT_SendDataPacket(tTCPConnection *Connection, size_t Length, const voi
 /**
  * \brief Send some bytes on a connection
  */
-size_t TCP_Client_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer)
+size_t TCP_Client_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void *Buffer, Uint Flags)
 {
 	tTCPConnection	*conn = Node->ImplPtr;
 	size_t	rem = Length;
@@ -1194,12 +1320,23 @@ size_t TCP_Client_Write(tVFS_Node *Node, off_t Offset, size_t Length, const void
 	// Don't allow a write to a closed connection
 	if( conn->State > TCP_ST_OPEN ) {
 		VFS_MarkError(Node, 1);
+		errno = 0;
 		LEAVE('i', -1);
 		return -1;
 	}
 	
 	// Wait
-	VFS_SelectNode(Node, VFS_SELECT_WRITE|VFS_SELECT_ERROR, NULL, "TCP_Client_Write");
+	{
+		tTime	*timeout = NULL;
+		tTime	timeout_zero = 0;
+		if( Flags & VFS_IOFLAG_NOBLOCK )
+			timeout = &timeout_zero;
+		if( !VFS_SelectNode(Node, VFS_SELECT_WRITE|VFS_SELECT_ERROR, timeout, "TCP_Client_Write") ) {
+			errno = EWOULDBLOCK;
+			LEAVE('i', -1);
+			return -1;
+		}
+	}
 	
 	do
 	{
@@ -1330,6 +1467,15 @@ void TCP_Client_Close(tVFS_Node *Node)
 	
 	ENTER("pNode", Node);
 	
+	ASSERT(Node->ReferenceCount != 0);
+
+	if( Node->ReferenceCount > 1 ) {
+		Node->ReferenceCount --;
+		LOG("Dereference only");
+		LEAVE('-');
+		return ;
+	}
+	
 	if( conn->State == TCP_ST_CLOSE_WAIT || conn->State == TCP_ST_OPEN )
 	{
 		packet.SourcePort = htons(conn->LocalPort);
@@ -1344,14 +1490,21 @@ void TCP_Client_Close(tVFS_Node *Node)
 		TCP_SendPacket( conn, &packet, 0, NULL );
 	}
 	
+	Time_RemoveTimer(conn->DeferredACKTimer);
+	
 	switch( conn->State )
 	{
+	case TCP_ST_CLOSED:
+		Log_Warning("TCP", "Closing connection that was never opened");
+		TCP_int_FreeTCB(conn);
+		break;
 	case TCP_ST_CLOSE_WAIT:
 		conn->State = TCP_ST_LAST_ACK;
 		break;
 	case TCP_ST_OPEN:
 		conn->State = TCP_ST_FIN_WAIT1;
-		while( conn->State == TCP_ST_FIN_WAIT1 )	Threads_Yield();
+		while( conn->State == TCP_ST_FIN_WAIT1 )
+			Threads_Yield();
 		break;
 	default:
 		Log_Warning("TCP", "Unhandled connection state %i in TCP_Client_Close",
@@ -1359,10 +1512,6 @@ void TCP_Client_Close(tVFS_Node *Node)
 		break;
 	}
 	
-	Time_RemoveTimer(conn->DeferredACKTimer);
-	Time_FreeTimer(conn->DeferredACKTimer);
-	free(conn);
-	
 	LEAVE('-');
 }