Kernel - Cleaning up messages
[tpg/acess2.git] / Modules / IPStack / tcp.c
index 326f044..bb71fdb 100644 (file)
@@ -2,26 +2,39 @@
  * Acess2 IP Stack
  * - TCP Handling
  */
+#define DEBUG  1
 #include "ipstack.h"
 #include "ipv4.h"
+#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
 
+#define TCP_MAX_PACKET_SIZE    1024
+#define TCP_WINDOW_SIZE        0x2000
+#define TCP_RECIEVE_BUFFER_SIZE        0x4000
+
 // === PROTOTYPES ===
-void   TCP_Initialise();
+void   TCP_Initialise(void);
 void   TCP_StartConnection(tTCPConnection *Conn);
 void   TCP_SendPacket(tTCPConnection *Conn, size_t Length, tTCPHeader *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);
 Uint16 TCP_GetUnusedPort();
  int   TCP_AllocatePort(Uint16 Port);
  int   TCP_DeallocatePort(Uint16 Port);
 // --- Server
 tVFS_Node      *TCP_Server_Init(tInterface *Interface);
 char   *TCP_Server_ReadDir(tVFS_Node *Node, int Pos);
-tVFS_Node      *TCP_Server_FindDir(tVFS_Node *Node, char *Name);
+tVFS_Node      *TCP_Server_FindDir(tVFS_Node *Node, const char *Name);
  int   TCP_Server_IOCtl(tVFS_Node *Node, int ID, void *Data);
 void   TCP_Server_Close(tVFS_Node *Node);
 // --- Client
@@ -30,6 +43,8 @@ Uint64        TCP_Client_Read(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buff
 Uint64 TCP_Client_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer);
  int   TCP_Client_IOCtl(tVFS_Node *Node, int ID, void *Data);
 void   TCP_Client_Close(tVFS_Node *Node);
+// --- Helpers
+ int   WrapBetween(Uint32 Lower, Uint32 Value, Uint32 Higher, Uint32 MaxValue);
 
 // === TEMPLATES ===
 tSocketFile    gTCP_ServerFile = {NULL, "tcps", TCP_Server_Init};
@@ -37,76 +52,82 @@ tSocketFile gTCP_ClientFile = {NULL, "tcpc", TCP_Client_Init};
 
 // === GLOBALS ===
  int   giTCP_NumHalfopen = 0;
-tSpinlock      glTCP_Listeners;
+tShortSpinlock glTCP_Listeners;
 tTCPListener   *gTCP_Listeners;
-tSpinlock      glTCP_OutbountCons;
+tShortSpinlock glTCP_OutbountCons;
 tTCPConnection *gTCP_OutbountCons;
 Uint32 gaTCP_PortBitmap[0x800];
  int   giTCP_NextOutPort = TCP_MIN_DYNPORT;
 
 // === CODE ===
 /**
- * \fn void TCP_Initialise()
  * \brief Initialise the TCP Layer
+ * 
+ * Registers the client and server files and the GetPacket callback
  */
-void TCP_Initialise()
+void TCP_Initialise(void)
 {
+       giTCP_NextOutPort += rand()%32;
        IPStack_AddFile(&gTCP_ServerFile);
        IPStack_AddFile(&gTCP_ClientFile);
        IPv4_RegisterCallback(IP4PROT_TCP, TCP_GetPacket);
-}
-
-/**
- * \brief Open a connection to another host using TCP
- */
-void TCP_StartConnection(tTCPConnection *Conn)
-{
-       tTCPHeader      hdr;
-
-       hdr.SourcePort = Conn->LocalPort;
-       hdr.DestPort = Conn->RemotePort;
-       Conn->NextSequenceSend = rand();
-       hdr.SequenceNumber = Conn->NextSequenceSend;
-       hdr.DataOffset = (sizeof(tTCPHeader)+3)/4;
-       hdr.Flags = TCP_FLAG_SYN;
-       hdr.WindowSize = 0;     // TODO
-       hdr.Checksum = 0;       // TODO
-       hdr.UrgentPointer = 0;
-       // SEND PACKET
-       TCP_SendPacket( Conn, sizeof(tTCPHeader), &hdr );
-       return ;
+       IPv6_RegisterCallback(IP4PROT_TCP, TCP_GetPacket);
 }
 
 /**
  * \brief Sends a packet from the specified connection, calculating the checksums
  * \param Conn Connection
  * \param Length       Length of data
- * \param Data Packet data
+ * \param Data Packet data (cast as a TCP Header)
  */
 void TCP_SendPacket( tTCPConnection *Conn, size_t Length, tTCPHeader *Data )
 {
-       size_t  buflen;
-       Uint32  *buf;
+       Uint16  checksum[2];
+       
+       Data->Checksum = 0;
+       checksum[1] = htons( ~IPv4_Checksum( (void*)Data, Length ) );   // Partial checksum
+       if(Length & 1)
+               ((Uint8*)Data)[Length] = 0;
+       
+       // TODO: Fragment packet
+       
        switch( Conn->Interface->Type )
        {
-       case 4: // Append IPv4 Pseudo Header
-               buflen = 4 + 4 + 4 + ((Length+1)&1);
-               buf = malloc( buflen );
-               buf[0] = Conn->Interface->IP4.Address.L;
-               buf[1] = Conn->RemoteIP.v4.L;
-               buf[2] = (htons(Length)<<16) | (6<<8) | 0;
-               Data->Checksum = 0;
-               memcpy( &buf[3], Data, Length );
-               Data->Checksum = IPv4_Checksum( buf, buflen );
-               free(buf);
-               IPv4_SendPacket(Conn->Interface, Conn->RemoteIP.v4, IP4PROT_TCP, 0, buflen, buf);
+       case 4:
+               // Append IPv4 Pseudo Header
+               {
+                       Uint32  buf[3];
+                       buf[0] = ((tIPv4*)Conn->Interface->Address)->L;
+                       buf[1] = Conn->RemoteIP.v4.L;
+                       buf[2] = (htons(Length)<<16) | (6<<8) | 0;
+                       checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );        // Partial checksum
+               }
+               Data->Checksum = htons( IPv4_Checksum(checksum, 2*2) ); // Combine the two
+               IPv4_SendPacket(Conn->Interface, Conn->RemoteIP.v4, IP4PROT_TCP, 0, Length, Data);
+               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);
+                       buf[8] = htonl(Length);
+                       buf[9] = htonl(6);
+                       checksum[0] = htons( ~IPv4_Checksum(buf, sizeof(buf)) );        // Partial checksum
+               }
+               Data->Checksum = htons( IPv4_Checksum(checksum, 2*2) ); // Combine the two
+               IPv6_SendPacket(Conn->Interface, Conn->RemoteIP.v6, IP4PROT_TCP, Length, Data);
                break;
        }
 }
 
 /**
- * \fn void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
  * \brief Handles a packet from the IP Layer
+ * \param Interface    Interface the packet arrived from
+ * \param Address      Pointer to the addres structure
+ * \param Length       Size of packet in bytes
+ * \param Buffer       Packet data
  */
 void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffer)
 {
@@ -114,25 +135,31 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
        tTCPListener    *srv;
        tTCPConnection  *conn;
 
-       Log("[TCP  ] sizeof(tTCPHeader) = %i", sizeof(tTCPHeader));
-       Log("[TCP  ] SourcePort = %i", ntohs(hdr->SourcePort));
-       Log("[TCP  ] DestPort = %i", ntohs(hdr->DestPort));
-       Log("[TCP  ] SequenceNumber = 0x%x", ntohl(hdr->SequenceNumber));
-       Log("[TCP  ] AcknowlegementNumber = 0x%x", ntohl(hdr->AcknowlegementNumber));
-       Log("[TCP  ] DataOffset = %i", hdr->DataOffset >> 4);
-       Log("[TCP  ] Flags = {");
-       Log("[TCP  ]   CWR = %B", !!(hdr->Flags & TCP_FLAG_CWR));
-       Log("[TCP  ]   ECE = %B", !!(hdr->Flags & TCP_FLAG_ECE));
-       Log("[TCP  ]   URG = %B", !!(hdr->Flags & TCP_FLAG_URG));
-       Log("[TCP  ]   ACK = %B", !!(hdr->Flags & TCP_FLAG_ACK));
-       Log("[TCP  ]   PSH = %B", !!(hdr->Flags & TCP_FLAG_PSH));
-       Log("[TCP  ]   RST = %B", !!(hdr->Flags & TCP_FLAG_RST));
-       Log("[TCP  ]   SYN = %B", !!(hdr->Flags & TCP_FLAG_SYN));
-       Log("[TCP  ]   FIN = %B", !!(hdr->Flags & TCP_FLAG_FIN));
-       Log("[TCP  ] }");
-       Log("[TCP  ] WindowSize = %i", htons(hdr->WindowSize));
-       Log("[TCP  ] Checksum = 0x%x", htons(hdr->Checksum));
-       Log("[TCP  ] UrgentPointer = 0x%x", htons(hdr->UrgentPointer));
+       Log_Log("TCP", "TCP_GetPacket: <Local>:%i from [%s]:%i, Flags= %s%s%s%s%s%s%s%s",
+               ntohs(hdr->SourcePort),
+               IPStack_PrintAddress(Interface->Type, Address),
+               ntohs(hdr->DestPort),
+               (hdr->Flags & TCP_FLAG_CWR) ? "CWR " : "",
+               (hdr->Flags & TCP_FLAG_ECE) ? "ECE " : "",
+               (hdr->Flags & TCP_FLAG_URG) ? "URG " : "",
+               (hdr->Flags & TCP_FLAG_ACK) ? "ACK " : "",
+               (hdr->Flags & TCP_FLAG_PSH) ? "PSH " : "",
+               (hdr->Flags & TCP_FLAG_RST) ? "RST " : "",
+               (hdr->Flags & TCP_FLAG_SYN) ? "SYN " : "",
+               (hdr->Flags & TCP_FLAG_FIN) ? "FIN " : ""
+               );
+
+       if( Length > (hdr->DataOffset >> 4)*4 )
+       {
+               Log_Log("TCP", "TCP_GetPacket: SequenceNumber = 0x%x", ntohl(hdr->SequenceNumber));
+#if HEXDUMP_INCOMING
+               Debug_HexDump(
+                       "TCP_GetPacket: Packet Data = ",
+                       (Uint8*)hdr + (hdr->DataOffset >> 4)*4,
+                       Length - (hdr->DataOffset >> 4)*4
+                       );
+#endif
+       }
 
        // Check Servers
        {
@@ -143,8 +170,9 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                        // Check the interface
                        if(srv->Interface && srv->Interface != Interface)       continue;
                        // Check the destination port
-                       if(srv->Port != hdr->DestPort)  continue;
-
+                       if(srv->Port != htons(hdr->DestPort))   continue;
+                       
+                       Log_Log("TCP", "TCP_GetPacket: Matches server %p", srv);
                        // Is this in an established connection?
                        for( conn = srv->Connections; conn; conn = conn->Next )
                        {
@@ -152,32 +180,34 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                                if(conn->Interface != Interface)        continue;
 
                                // Check Source Port
-                               if(conn->RemotePort != hdr->SourcePort) continue;
+                               Log_Log("TCP", "TCP_GetPacket: conn->RemotePort(%i) == hdr->SourcePort(%i)",
+                                       conn->RemotePort, ntohs(hdr->SourcePort));
+                               if(conn->RemotePort != ntohs(hdr->SourcePort))  continue;
 
                                // Check Source IP
-                               if(conn->Interface->Type == 6 && !IP6_EQU(conn->RemoteIP.v6, *(tIPv6*)Address))
-                                       continue;
-                               if(conn->Interface->Type == 4 && !IP4_EQU(conn->RemoteIP.v4, *(tIPv4*)Address))
-                                       continue;
+                               if( IPStack_CompareAddress(conn->Interface->Type, &conn->RemoteIP, Address, -1) != 0 )
+                                       continue ;
 
+                               Log_Log("TCP", "TCP_GetPacket: Matches connection %p", conn);
                                // We have a response!
                                TCP_INT_HandleConnectionPacket(conn, hdr, Length);
 
                                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("[TCP  ] Packet is not a SYN");
-                               continue;
+                               Log_Log("TCP", "TCP_GetPacket: Packet is not a SYN");
+                               return ;
                        }
                        
                        // TODO: Check for halfopen max
                        
                        conn = calloc(1, sizeof(tTCPConnection));
-                       conn->State = TCP_ST_HALFOPEN;
+                       conn->State = TCP_ST_SYN_RCVD;
                        conn->LocalPort = srv->Port;
-                       conn->RemotePort = hdr->SourcePort;
+                       conn->RemotePort = ntohs(hdr->SourcePort);
                        conn->Interface = Interface;
                        
                        switch(Interface->Type)
@@ -186,12 +216,15 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                        case 6: conn->RemoteIP.v6 = *(tIPv6*)Address;   break;
                        }
                        
-                       conn->NextSequenceRcv = ntohl( hdr->SequenceNumber );
+                       conn->RecievedBuffer = RingBuffer_Create( TCP_RECIEVE_BUFFER_SIZE );
+                       
+                       conn->NextSequenceRcv = ntohl( hdr->SequenceNumber ) + 1;
                        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.Read = TCP_Client_Read;
                        conn->Node.Write = TCP_Client_Write;
@@ -201,21 +234,28 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                        // as the interface is locked to the watching thread, and this
                        // runs in the watching thread. But, it's a good idea to have
                        // it, just in case
-                       LOCK(&srv->lConnections);
-                       conn->Next = srv->Connections;
-                       srv->Connections = conn;
-                       RELEASE(&srv->lConnections);
+                       // 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
+                               srv->ConnectionsTail->Next = conn;
+                       srv->ConnectionsTail = conn;
+                       if(!srv->NewConnections)
+                               srv->NewConnections = conn;
+                       SHORTREL(&srv->lConnections);
 
                        // Send the SYN ACK
-                       Log("[TCP  ] TODO: Sending SYN ACK");
                        hdr->Flags |= TCP_FLAG_ACK;
-                       hdr->AcknowlegementNumber = hdr->SequenceNumber;
-                       hdr->SequenceNumber = conn->NextSequenceSend;
+                       hdr->AcknowlegementNumber = htonl(conn->NextSequenceRcv);
+                       hdr->SequenceNumber = htonl(conn->NextSequenceSend);
                        hdr->DestPort = hdr->SourcePort;
-                       hdr->SourcePort = srv->Port;
+                       hdr->SourcePort = htons(srv->Port);
+                       hdr->DataOffset = (sizeof(tTCPHeader)/4) << 4;
                        TCP_SendPacket( conn, sizeof(tTCPHeader), hdr );
-
-                       break;
+                       conn->NextSequenceSend ++;
+                       return ;
                }
        }
 
@@ -228,7 +268,7 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                        if(conn->Interface != Interface)        continue;
 
                        // Check Source Port
-                       if(conn->RemotePort != hdr->SourcePort) continue;
+                       if(conn->RemotePort != ntohs(hdr->SourcePort))  continue;
 
                        // Check Source IP
                        if(conn->Interface->Type == 6 && !IP6_EQU(conn->RemoteIP.v6, *(tIPv6*)Address))
@@ -237,66 +277,481 @@ void TCP_GetPacket(tInterface *Interface, void *Address, int Length, void *Buffe
                                continue;
 
                        TCP_INT_HandleConnectionPacket(conn, hdr, Length);
+                       return ;
                }
        }
+       
+       Log_Log("TCP", "TCP_GetPacket: No Match");
 }
 
 /**
  * \brief Handles a packet sent to a specific connection
+ * \param Connection   TCP Connection pointer
+ * \param Header       TCP Packet pointer
+ * \param Length       Length of the packet
  */
 void TCP_INT_HandleConnectionPacket(tTCPConnection *Connection, tTCPHeader *Header, int Length)
-{      
-       tTCPStoredPacket        *pkt;
+{
         int    dataLen;
+       Uint32  sequence_num;
+       
+       // Silently drop once finished
+       // TODO: Check if this needs to be here
+       if( Connection->State == TCP_ST_FINISHED ) {
+               Log_Log("TCP", "Packet ignored - connection finnished");
+               return ;
+       }
        
-       Connection->State = TCP_ST_OPEN;
+       // Syncronise sequence values
        if(Header->Flags & TCP_FLAG_SYN) {
-               Connection->NextSequenceRcv = Header->SequenceNumber + 1;
+               // TODO: What if the packet also has data?
+               Connection->NextSequenceRcv = ntohl(Header->SequenceNumber);
        }
        
+       // Ackowledge a sent packet
        if(Header->Flags & TCP_FLAG_ACK) {
                // TODO: Process an ACKed Packet
-               Log("[TCP  ] Conn %p, Packet 0x%x ACKed", Connection, Header->AcknowlegementNumber);
-               return ;
+               Log_Log("TCP", "Conn %p, Sent packet 0x%x ACKed", Connection, Header->AcknowlegementNumber);
        }
        
-       // Allocate and fill cached packet
-       dataLen =  Length - (Header->DataOffset&0xF)*4;
-       pkt = malloc( dataLen + sizeof(tTCPStoredPacket) );
-       pkt->Next = NULL;
-       pkt->Sequence = Header->SequenceNumber;
-       memcpy(pkt->Data, (Uint8*)Header + (Header->DataOffset&0xF)*4, dataLen);
+       // Get length of data
+       dataLen = Length - (Header->DataOffset>>4)*4;
+       Log_Log("TCP", "HandleConnectionPacket - dataLen = %i", dataLen);
        
-       if( Header->SequenceNumber != Connection->NextSequenceRcv )
+       // 
+       // State Machine
+       //
+       switch( Connection->State )
        {
-               tTCPStoredPacket        *tmp, *prev;
-               for(tmp = Connection->FuturePackets;
-                       tmp;
-                       prev = tmp, tmp = tmp->Next)
+       // Pre-init connection?
+       case TCP_ST_CLOSED:
+               Log_Log("TCP", "Packets to a closed connection?!");
+               break;
+       
+       // --- Init States ---
+       // SYN sent, expecting SYN-ACK Connection Opening
+       case TCP_ST_SYN_SENT:
+               if( Header->Flags & TCP_FLAG_SYN )
+               {
+                       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, sizeof(tTCPHeader), Header );
+                       
+                       if( Header->Flags & TCP_FLAG_ACK )
+                       {       
+                               Log_Log("TCP", "ACKing SYN-ACK");
+                               Connection->State = TCP_ST_OPEN;
+                       }
+                       else
+                       {
+                               Log_Log("TCP", "ACKing SYN");
+                               Connection->State = TCP_ST_SYN_RCVD;
+                       }
+               }
+               break;
+       
+       // SYN-ACK sent, expecting ACK
+       case TCP_ST_SYN_RCVD:
+               if( Header->Flags & TCP_FLAG_ACK )
                {
-                       if(tmp->Sequence > pkt->Sequence)       break;
+                       // TODO: Handle max half-open limit
+                       Connection->State = TCP_ST_OPEN;
+                       Log_Log("TCP", "Connection fully opened");
                }
-               if(prev)
-                       prev->Next = pkt;
+               break;
+               
+       // --- Established State ---
+       case TCP_ST_OPEN:
+               // - Handle State changes
+               //
+               if( Header->Flags & TCP_FLAG_FIN ) {
+                       Log_Log("TCP", "Conn %p closed, recieved FIN", Connection);
+                       VFS_MarkError(&Connection->Node, 1);
+                       Connection->State = TCP_ST_CLOSE_WAIT;
+//                     Header->Flags &= ~TCP_FLAG_FIN;
+                       // CLOSE WAIT requires the client to close (or does it?)
+                       #if 0
+                       
+                       #endif
+               }
+       
+               // Check for an empty packet
+               if(dataLen == 0) {
+                       if( Header->Flags == TCP_FLAG_ACK )
+                       {
+                               Log_Log("TCP", "ACK only packet");
+                               return ;
+                       }
+                       Connection->NextSequenceRcv ++; // TODO: Is this right? (empty packet counts as one byte)
+                       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, sizeof(tTCPHeader), Header );
+                       return ;
+               }
+               
+               // NOTES:
+               // Flags
+               //    PSH - Has Data?
+               // /NOTES
+               
+               sequence_num = ntohl(Header->SequenceNumber);
+               
+               Log_Log("TCP", "0x%08x <= 0x%08x < 0x%08x",
+                       Connection->NextSequenceRcv,
+                       ntohl(Header->SequenceNumber),
+                       Connection->NextSequenceRcv + TCP_WINDOW_SIZE
+                       );
+               
+               // Is this packet the next expected packet?
+               if( sequence_num == Connection->NextSequenceRcv )
+               {
+                        int    rv;
+                       // Ooh, Goodie! Add it to the recieved list
+                       rv = TCP_INT_AppendRecieved(Connection,
+                               (Uint8*)Header + (Header->DataOffset>>4)*4,
+                               dataLen
+                               );
+                       if(rv != 0) {
+                               break;
+                       }
+                       Log_Log("TCP", "0x%08x += %i", Connection->NextSequenceRcv, dataLen);
+                       Connection->NextSequenceRcv += dataLen;
+                       
+                       // TODO: This should be moved out of the watcher thread,
+                       // so that a single lost packet on one connection doesn't cause
+                       // all connections on the interface to lag.
+                       // - Meh, no real issue, as the cache shouldn't be that large
+                       TCP_INT_UpdateRecievedFromFuture(Connection);
+               
+                       // ACK Packet
+                       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_SYN;  // Eliminate all flags save for SYN
+                       Header->Flags |= TCP_FLAG_ACK;  // Add ACK
+                       Log_Log("TCP", "Sending ACK for 0x%08x", Connection->NextSequenceRcv);
+                       TCP_SendPacket( Connection, sizeof(tTCPHeader), Header );
+                       //Connection->NextSequenceSend ++;
+               }
+               // Check if the packet is in window
+               else if( WrapBetween(Connection->NextSequenceRcv, sequence_num,
+                               Connection->NextSequenceRcv+TCP_WINDOW_SIZE, 0xFFFFFFFF) )
+               {
+                       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 ++ )
+                       {
+                               Connection->FuturePacketValidBytes[index/8] |= 1 << (index%8);
+                               Connection->FuturePacketData[index] = dataptr[i];
+                               // Do a wrap increment
+                               index ++;
+                               if(index == TCP_WINDOW_SIZE)    index = 0;
+                       }
+                       #else
+                       tTCPStoredPacket        *pkt, *tmp, *prev = NULL;
+                       
+                       // Allocate and fill cached packet
+                       pkt = malloc( sizeof(tTCPStoredPacket) + dataLen );
+                       pkt->Next = NULL;
+                       pkt->Sequence = ntohl(Header->SequenceNumber);
+                       pkt->Length = dataLen;
+                       memcpy(pkt->Data, dataptr, dataLen);
+                       
+                       Log_Log("TCP", "We missed a packet, caching",
+                               pkt->Sequence, Connection->NextSequenceRcv);
+                       
+                       // No? Well, let's cache it and look at it later
+                       SHORTLOCK( &Connection->lFuturePackets );
+                       for(tmp = Connection->FuturePackets;
+                               tmp;
+                               prev = tmp, tmp = tmp->Next)
+                       {
+                               if(tmp->Sequence >= pkt->Sequence)      break;
+                       }
+                       
+                       // Add if before first, or sequences don't match 
+                       if( !tmp || tmp->Sequence != pkt->Sequence )
+                       {
+                               if(prev)
+                                       prev->Next = pkt;
+                               else
+                                       Connection->FuturePackets = pkt;
+                               pkt->Next = tmp;
+                       }
+                       // Replace if larger
+                       else if(pkt->Length > tmp->Length)
+                       {
+                               if(prev)
+                                       prev->Next = pkt;
+                               pkt->Next = tmp->Next;
+                               free(tmp);
+                       }
+                       else
+                       {
+                               free(pkt);      // TODO: Find some way to remove this
+                       }
+                       SHORTREL( &Connection->lFuturePackets );
+                       #endif
+               }
+               // Badly out of sequence packet
                else
-                       Connection->FuturePackets = pkt;
-               pkt->Next = tmp;
+               {
+                       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);
+                       // TODO: Spec says we should send an empty ACK with the current state
+               }
+               break;
+       
+       // --- Remote close states
+       case TCP_ST_CLOSE_WAIT:
+               
+               // Ignore everything, CLOSE_WAIT is terminated by the client
+               Log_Debug("TCP", "CLOSE WAIT - Ignoring packets");
+               
+               break;
+       
+       // LAST-ACK - Waiting for the ACK of FIN (from CLOSE WAIT)
+       case TCP_ST_LAST_ACK:
+               if( Header->Flags & TCP_FLAG_ACK )
+               {
+                       Connection->State = TCP_ST_FINISHED;    // Connection completed
+                       Log_Log("TCP", "LAST-ACK to CLOSED - Connection remote closed");
+                       // TODO: Destrory the TCB
+               }
+               break;
+       
+       // --- Local close States
+       case TCP_ST_FIN_WAIT1:
+               if( Header->Flags & TCP_FLAG_FIN )
+               {
+                       Connection->State = TCP_ST_CLOSING;
+                       Log_Debug("TCP", "Conn %p closed, sent FIN and recieved FIN", Connection);
+                       VFS_MarkError(&Connection->Node, 1);
+                       
+                       // ACK Packet
+                       Header->DestPort = Header->SourcePort;
+                       Header->SourcePort = htons(Connection->LocalPort);
+                       Header->AcknowlegementNumber = Header->SequenceNumber;
+                       Header->SequenceNumber = htonl(Connection->NextSequenceSend);
+                       Header->WindowSize = htons(TCP_WINDOW_SIZE);
+                       Header->Flags = TCP_FLAG_ACK;
+                       TCP_SendPacket( Connection, sizeof(tTCPHeader), Header );
+                       break ;
+               }
+               
+               // TODO: Make sure that the packet is actually ACKing the FIN
+               if( Header->Flags & TCP_FLAG_ACK )
+               {
+                       Connection->State = TCP_ST_FIN_WAIT2;
+                       Log_Debug("TCP", "Conn %p closed, sent FIN ACKed", Connection);
+                       VFS_MarkError(&Connection->Node, 1);
+                       return ;
+               }
+               break;
+       
+       case TCP_ST_FIN_WAIT2:
+               if( Header->Flags & TCP_FLAG_FIN )
+               {
+                       Connection->State = TCP_ST_TIME_WAIT;
+                       Log_Debug("TCP", "FIN sent and recieved, ACKing and going into TIME WAIT %p FINWAIT-2 -> TIME WAIT", Connection);
+                       // Send ACK
+                       Header->DestPort = Header->SourcePort;
+                       Header->SourcePort = htons(Connection->LocalPort);
+                       Header->AcknowlegementNumber = Header->SequenceNumber;
+                       Header->SequenceNumber = htonl(Connection->NextSequenceSend);
+                       Header->WindowSize = htons(TCP_WINDOW_SIZE);
+                       Header->Flags = TCP_FLAG_ACK;
+                       TCP_SendPacket( Connection, sizeof(tTCPHeader), Header );
+               }
+               break;
+       
+       case TCP_ST_CLOSING:
+               // TODO: Make sure that the packet is actually ACKing the FIN
+               if( Header->Flags & TCP_FLAG_ACK )
+               {
+                       Connection->State = TCP_ST_TIME_WAIT;
+                       Log_Debug("TCP", "Conn %p CLOSING -> TIME WAIT", Connection);
+                       VFS_MarkError(&Connection->Node, 1);
+                       return ;
+               }
+               break;
+       
+       // --- Closed (or near closed) states) ---
+       case TCP_ST_TIME_WAIT:
+               Log_Log("TCP", "Packets on Time-Wait, ignored");
+               break;
+       
+       case TCP_ST_FINISHED:
+               Log_Log("TCP", "Packets when CLOSED, ignoring");
+               break;
+       
+       //default:
+       //      Log_Warning("TCP", "Unhandled TCP state %i", Connection->State);
+       //      break;
+       }
+       
+}
+
+/**
+ * \brief Appends a packet to the recieved list
+ * \param Connection   Connection structure
+ * \param Data Packet contents
+ * \param Length       Length of \a Data
+ */
+int TCP_INT_AppendRecieved(tTCPConnection *Connection, const void *Data, size_t Length)
+{
+       Mutex_Acquire( &Connection->lRecievedPackets );
+
+       if(Connection->RecievedBuffer->Length + Length > Connection->RecievedBuffer->Space )
+       {
+               VFS_MarkAvaliable(&Connection->Node, 1);
+               Log_Error("TCP", "Buffer filled, packet dropped (:%i) - %i + %i > %i",
+                       Connection->LocalPort, Connection->RecievedBuffer->Length, Length,
+                       Connection->RecievedBuffer->Space
+                       );
+               Mutex_Release( &Connection->lRecievedPackets );
+               return 1;
+       }
+       
+       RingBuffer_Write( Connection->RecievedBuffer, Data, Length );
+
+       VFS_MarkAvaliable(&Connection->Node, 1);
+       
+       Mutex_Release( &Connection->lRecievedPackets );
+       return 0;
+}
+
+/**
+ * \brief Updates the connections recieved list from the future list
+ * \param Connection   Connection structure
+ * 
+ * Updates the recieved packets list with packets from the future (out 
+ * of order) packets list that are now able to be added in direct
+ * sequence.
+ */
+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 ++ )
+       {
+               if( Connection->FuturePacketValidBytes[i / 8] == 0xFF ) {
+                       i += 7; index += 7;
+                       continue;
+               }
+               else if( !(Connection->FuturePacketValidBytes[i / 8] & (1 << (i%8))) )
+                       break;
+               
+               index ++;
+               if(index > TCP_WINDOW_SIZE)
+                       index -= TCP_WINDOW_SIZE;
+       }
+       length = i;
+       
+       index = Connection->NextSequenceRcv % TCP_WINDOW_SIZE;
+       
+       // Write data to to the ring buffer
+       if( TCP_WINDOW_SIZE - index > length )
+       {
+               // Simple case
+               RingBuffer_Write( Connection->RecievedBuffer, Connection->FuturePacketData + index, length );
        }
        else
        {
-               LOCK( &Connection->lRecievedPackets );
-               if(Connection->RecievedPackets)
+                int    endLen = TCP_WINDOW_SIZE - index;
+               // 2-part case
+               RingBuffer_Write( Connection->RecievedBuffer, Connection->FuturePacketData + index, endLen );
+               RingBuffer_Write( Connection->RecievedBuffer, Connection->FuturePacketData, endLen - length );
+       }
+       
+       // Mark (now saved) bytes as invalid
+       // - Align index
+       while(index % 8 && length)
+       {
+               Connection->FuturePacketData[index] = 0;
+               Connection->FuturePacketData[index/8] &= ~(1 << (index%8));
+               index ++;
+               if(index > TCP_WINDOW_SIZE)
+                       index -= TCP_WINDOW_SIZE;
+               length --;
+       }
+       while( length > 7 )
+       {
+               Connection->FuturePacketData[index] = 0;
+               Connection->FuturePacketValidBytes[index/8] = 0;
+               length -= 8;
+               index += 8;
+               if(index > TCP_WINDOW_SIZE)
+                       index -= TCP_WINDOW_SIZE;
+       }
+       while(length)
+       {
+               Connection->FuturePacketData[index] = 0;
+               Connection->FuturePacketData[index/8] &= ~(1 << (index%8));
+               index ++;
+               if(index > TCP_WINDOW_SIZE)
+                       index -= TCP_WINDOW_SIZE;
+               length --;
+       }
+       
+       #else
+       tTCPStoredPacket        *pkt;
+       for(;;)
+       {
+               SHORTLOCK( &Connection->lFuturePackets );
+               
+               // Clear out duplicates from cache
+               // - If a packet has just been recieved, and it is expected, then
+               //   (since NextSequenceRcv = rcvd->Sequence + rcvd->Length) all
+               //   packets in cache that are smaller than the next expected
+               //   are now defunct.
+               pkt = Connection->FuturePackets;
+               while(pkt && pkt->Sequence < Connection->NextSequenceRcv)
                {
-                       Connection->RecievedPacketsTail->Next = pkt;
-                       Connection->RecievedPacketsTail = pkt;
+                       tTCPStoredPacket        *next = pkt->Next;
+                       free(pkt);
+                       pkt = next;
                }
-               else
-               {
-                       Connection->RecievedPackets = pkt;
-                       Connection->RecievedPacketsTail = pkt;
+               
+               // If there's no packets left in cache, stop looking
+               if(!pkt || pkt->Sequence > Connection->NextSequenceRcv) {
+                       SHORTREL( &Connection->lFuturePackets );
+                       return;
                }
-               RELEASE( &Connection->lRecievedPackets );
+               
+               // Delete packet from future list
+               Connection->FuturePackets = pkt->Next;
+               
+               // Release list
+               SHORTREL( &Connection->lFuturePackets );
+               
+               // Looks like we found one
+               TCP_INT_AppendRecieved(Connection, pkt);
+               Connection->NextSequenceRcv += pkt->Length;
+               free(pkt);
        }
+       #endif
 }
 
 /**
@@ -359,13 +814,24 @@ int TCP_DeallocatePort(Uint16 Port)
 // --- Server
 tVFS_Node *TCP_Server_Init(tInterface *Interface)
 {
-       tTCPListener    *srv = malloc( sizeof(tTCPListener) );
+       tTCPListener    *srv;
+       
+       srv = malloc( sizeof(tTCPListener) );
+
+       if( srv == NULL ) {
+               Log_Warning("TCP", "malloc failed for listener (%i) bytes", sizeof(tTCPListener));
+               return NULL;
+       }
 
        srv->Interface = Interface;
        srv->Port = 0;
        srv->NextID = 0;
        srv->Connections = NULL;
+       srv->ConnectionsTail = NULL;
+       srv->NewConnections = NULL;
        srv->Next = NULL;
+       srv->Node.Flags = VFS_FFLAG_DIRECTORY;
+       srv->Node.Size = -1;
        srv->Node.ImplPtr = srv;
        srv->Node.NumACLs = 1;
        srv->Node.ACLs = &gVFS_ACL_EveryoneRW;
@@ -374,10 +840,10 @@ tVFS_Node *TCP_Server_Init(tInterface *Interface)
        srv->Node.IOCtl = TCP_Server_IOCtl;
        srv->Node.Close = TCP_Server_Close;
 
-       LOCK(&glTCP_Listeners);
+       SHORTLOCK(&glTCP_Listeners);
        srv->Next = gTCP_Listeners;
        gTCP_Listeners = srv;
-       RELEASE(&glTCP_Listeners);
+       SHORTREL(&glTCP_Listeners);
 
        return &srv->Node;
 }
@@ -393,14 +859,36 @@ char *TCP_Server_ReadDir(tVFS_Node *Node, int Pos)
        tTCPListener    *srv = Node->ImplPtr;
        tTCPConnection  *conn;
        char    *ret;
+       
+       ENTER("pNode iPos", Node, Pos);
 
-       while( srv->NewConnections == NULL )    Threads_Yield();
+       Log_Log("TCP", "Thread %i waiting for a connection", Threads_GetTID());
+       for(;;)
+       {
+               SHORTLOCK( &srv->lConnections );
+               if( srv->NewConnections != NULL )       break;
+               SHORTREL( &srv->lConnections );
+               Threads_Yield();        // TODO: Sleep until poked
+               continue;
+       }
+       
 
+       // Increment the new list (the current connection is still on the 
+       // normal list)
        conn = srv->NewConnections;
        srv->NewConnections = conn->Next;
+       
+       SHORTREL( &srv->lConnections );
+       
+       LOG("conn = %p", conn);
+       LOG("srv->Connections = %p", srv->Connections);
+       LOG("srv->NewConnections = %p", srv->NewConnections);
+       LOG("srv->ConnectionsTail = %p", srv->ConnectionsTail);
 
        ret = malloc(9);
-       itoa(ret, Node->ImplInt, 16, '0', 8);
+       itoa(ret, conn->Node.ImplInt, 16, 8, '0');
+       Log_Log("TCP", "Thread %i got '%s'", Threads_GetTID(), ret);
+       LEAVE('s', ret);
        return ret;
 }
 
@@ -409,11 +897,53 @@ char *TCP_Server_ReadDir(tVFS_Node *Node, int Pos)
  * \param Node Server node
  * \param Name Hexadecimal ID of the node
  */
-tVFS_Node *TCP_Server_FindDir(tVFS_Node *Node, char *Name)
+tVFS_Node *TCP_Server_FindDir(tVFS_Node *Node, const char *Name)
 {
-       return NULL;
+       tTCPConnection  *conn;
+       tTCPListener    *srv = Node->ImplPtr;
+       char    tmp[9];
+        int    id = atoi(Name);
+       
+       ENTER("pNode sName", Node, Name);
+       
+       // Sanity Check
+       itoa(tmp, id, 16, 8, '0');
+       if(strcmp(tmp, Name) != 0) {
+               LOG("'%s' != '%s' (%08x)", Name, tmp, id);
+               LEAVE('n');
+               return NULL;
+       }
+       
+       Log_Debug("TCP", "srv->Connections = %p", srv->Connections);
+       Log_Debug("TCP", "srv->NewConnections = %p", srv->NewConnections);
+       Log_Debug("TCP", "srv->ConnectionsTail = %p", srv->ConnectionsTail);
+       
+       // Search
+       SHORTLOCK( &srv->lConnections );
+       for(conn = srv->Connections;
+               conn;
+               conn = conn->Next)
+       {
+               LOG("conn->Node.ImplInt = %i", conn->Node.ImplInt);
+               if(conn->Node.ImplInt == id)    break;
+       }
+       SHORTREL( &srv->lConnections );
+       
+       // If not found, ret NULL
+       if(!conn) {
+               LOG("Connection %i not found", id);
+               LEAVE('n');
+               return NULL;
+       }
+       
+       // Return node
+       LEAVE('p', &conn->Node);
+       return &conn->Node;
 }
 
+/**
+ * \brief Handle IOCtl calls
+ */
 int TCP_Server_IOCtl(tVFS_Node *Node, int ID, void *Data)
 {
        tTCPListener    *srv = Node->ImplPtr;
@@ -444,6 +974,9 @@ int TCP_Server_IOCtl(tVFS_Node *Node, int ID, void *Data)
                        srv->Port = TCP_GetUnusedPort();
                else    // Else, mark this as used
                        TCP_AllocatePort(srv->Port);
+               
+               Log_Log("TCP", "Server %p listening on port %i", srv, srv->Port);
+               
                return srv->Port;
        }
        return 0;
@@ -455,15 +988,17 @@ void TCP_Server_Close(tVFS_Node *Node)
 }
 
 // --- Client
+/**
+ * \brief Create a client node
+ */
 tVFS_Node *TCP_Client_Init(tInterface *Interface)
 {
-       tTCPConnection  *conn = malloc( sizeof(tTCPConnection) );
+       tTCPConnection  *conn = calloc( sizeof(tTCPConnection) + TCP_WINDOW_SIZE + TCP_WINDOW_SIZE/8, 1 );
 
        conn->State = TCP_ST_CLOSED;
        conn->Interface = Interface;
-       conn->LocalPort = 0;
-       conn->RemotePort = 0;
-       memset( &conn->RemoteIP, 0, sizeof(conn->RemoteIP) );
+       conn->LocalPort = -1;
+       conn->RemotePort = -1;
 
        conn->Node.ImplPtr = conn;
        conn->Node.NumACLs = 1;
@@ -473,22 +1008,183 @@ tVFS_Node *TCP_Client_Init(tInterface *Interface)
        conn->Node.IOCtl = TCP_Client_IOCtl;
        conn->Node.Close = TCP_Client_Close;
 
-       LOCK(&glTCP_OutbountCons);
+       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
+
+       SHORTLOCK(&glTCP_OutbountCons);
        conn->Next = gTCP_OutbountCons;
        gTCP_OutbountCons = conn;
-       RELEASE(&glTCP_OutbountCons);
+       SHORTREL(&glTCP_OutbountCons);
 
        return &conn->Node;
 }
 
+/**
+ * \brief Wait for a packet and return it
+ * \note If \a Length is smaller than the size of the packet, the rest
+ *       of the packet's data will be discarded.
+ */
 Uint64 TCP_Client_Read(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 {
-       return 0;
+       tTCPConnection  *conn = Node->ImplPtr;
+       size_t  len;
+       
+       ENTER("pNode XOffset XLength pBuffer", Node, Offset, Length, Buffer);
+       LOG("conn = %p {State:%i}", conn, conn->State);
+       
+       // Check if connection is estabilishing
+       // - TODO: Sleep instead (maybe using VFS_SelectNode to wait for the
+       //   data to be availiable
+       while( conn->State == TCP_ST_SYN_RCVD || conn->State == TCP_ST_SYN_SENT )
+               Threads_Yield();
+       
+       // If the conneciton is not open, then clean out the recieved buffer
+       if( conn->State != TCP_ST_OPEN )
+       {
+               Mutex_Acquire( &conn->lRecievedPackets );
+               len = RingBuffer_Read( Buffer, conn->RecievedBuffer, Length );
+               Mutex_Release( &conn->lRecievedPackets );
+               
+               if( len == 0 ) {
+                       VFS_MarkAvaliable(Node, 0);
+                       LEAVE('i', -1);
+                       return -1;
+               }
+               
+               LEAVE('i', len);
+               return len;
+       }
+       
+       // Wait
+       VFS_SelectNode(Node, VFS_SELECT_READ|VFS_SELECT_ERROR, NULL, "TCP_Client_Read");
+       
+       // Lock list and read as much as possible (up to `Length`)
+       Mutex_Acquire( &conn->lRecievedPackets );
+       len = RingBuffer_Read( Buffer, conn->RecievedBuffer, Length );
+       
+       if( len == 0 || conn->RecievedBuffer->Length == 0 ) {
+               LOG("Marking as none avaliable (len = %i)", len);
+               VFS_MarkAvaliable(Node, 0);
+       }
+               
+       // Release the lock (we don't need it any more)
+       Mutex_Release( &conn->lRecievedPackets );
+
+       LEAVE('i', len);
+       return len;
 }
 
+/**
+ * \brief Send a data packet on a connection
+ */
+void TCP_INT_SendDataPacket(tTCPConnection *Connection, size_t Length, void *Data)
+{
+       char    buf[sizeof(tTCPHeader)+Length];
+       tTCPHeader      *packet = (void*)buf;
+       
+       packet->SourcePort = htons(Connection->LocalPort);
+       packet->DestPort = htons(Connection->RemotePort);
+       packet->DataOffset = (sizeof(tTCPHeader)/4)*16;
+       packet->WindowSize = htons(TCP_WINDOW_SIZE);
+       
+       packet->AcknowlegementNumber = htonl(Connection->NextSequenceRcv);
+       packet->SequenceNumber = htonl(Connection->NextSequenceSend);
+       packet->Flags = TCP_FLAG_PSH|TCP_FLAG_ACK;      // Hey, ACK if you can!
+       
+       memcpy(packet->Options, Data, Length);
+       
+       Log_Debug("TCP", "Send sequence 0x%08x", Connection->NextSequenceSend);
+#if HEXDUMP_OUTGOING
+       Debug_HexDump("TCP_INT_SendDataPacket: Data = ", Data, Length);
+#endif
+       
+       TCP_SendPacket( Connection, sizeof(tTCPHeader)+Length, packet );
+       
+       Connection->NextSequenceSend += Length;
+}
+
+/**
+ * \brief Send some bytes on a connection
+ */
 Uint64 TCP_Client_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buffer)
 {
-       return 0;
+       tTCPConnection  *conn = Node->ImplPtr;
+       size_t  rem = Length;
+       
+       ENTER("pNode XOffset XLength pBuffer", Node, Offset, Length, Buffer);
+       
+//     #if DEBUG
+//     Debug_HexDump("TCP_Client_Write: Buffer = ",
+//             Buffer, Length);
+//     #endif
+       
+       // Check if connection is open
+       while( conn->State == TCP_ST_SYN_RCVD || conn->State == TCP_ST_SYN_SENT )
+               Threads_Yield();
+       
+       if( conn->State != TCP_ST_OPEN ) {
+               VFS_MarkError(Node, 1);
+               LEAVE('i', -1);
+               return -1;
+       }
+       
+       do
+       {
+                int    len = (rem < TCP_MAX_PACKET_SIZE) ? rem : TCP_MAX_PACKET_SIZE;
+               
+               #if 0
+               // Wait for space in the buffer
+               Semaphore_Signal( &Connection->SentBufferSpace, len );
+               
+               // Save data to buffer (and update the length read by the ammount written)
+               len = RingBuffer_Write( &Connection->SentBuffer, Buffer, len);
+               #endif
+               
+               // Send packet
+               TCP_INT_SendDataPacket(conn, len, Buffer);
+               
+               Buffer += len;
+               rem -= len;
+       } while( rem > 0 );
+       
+       LEAVE('i', Length);
+       return Length;
+}
+
+/**
+ * \brief Open a connection to another host using TCP
+ * \param Conn Connection structure
+ */
+void TCP_StartConnection(tTCPConnection *Conn)
+{
+       tTCPHeader      hdr = {0};
+
+       Conn->State = TCP_ST_SYN_SENT;
+
+       hdr.SourcePort = htons(Conn->LocalPort);
+       hdr.DestPort = htons(Conn->RemotePort);
+       Conn->NextSequenceSend = rand();
+       hdr.SequenceNumber = htonl(Conn->NextSequenceSend);
+       hdr.DataOffset = (sizeof(tTCPHeader)/4) << 4;
+       hdr.Flags = TCP_FLAG_SYN;
+       hdr.WindowSize = htons(TCP_WINDOW_SIZE);        // Max
+       hdr.Checksum = 0;       // TODO
+       
+       TCP_SendPacket( Conn, sizeof(tTCPHeader), &hdr );
+       
+       Conn->NextSequenceSend ++;
+       Conn->State = TCP_ST_SYN_SENT;
+
+       return ;
 }
 
 /**
@@ -497,53 +1193,70 @@ Uint64 TCP_Client_Write(tVFS_Node *Node, Uint64 Offset, Uint64 Length, void *Buf
 int TCP_Client_IOCtl(tVFS_Node *Node, int ID, void *Data)
 {
        tTCPConnection  *conn = Node->ImplPtr;
+       
+       ENTER("pNode iID pData", Node, ID, Data);
 
        switch(ID)
        {
        case 4: // Get/Set local port
                if(!Data)
-                       return conn->LocalPort;
+                       LEAVE_RET('i', conn->LocalPort);
                if(conn->State != TCP_ST_CLOSED)
-                       return -1;
+                       LEAVE_RET('i', -1);
                if(!CheckMem(Data, sizeof(Uint16)))
-                       return -1;
+                       LEAVE_RET('i', -1);
 
                if(Threads_GetUID() != 0 && *(Uint16*)Data < 1024)
-                       return -1;
+                       LEAVE_RET('i', -1);
 
                conn->LocalPort = *(Uint16*)Data;
-               return 0;
+               LEAVE_RET('i', conn->LocalPort);
 
        case 5: // Get/Set remote port
-               if(!Data)       return conn->RemotePort;
-               if(conn->State != TCP_ST_CLOSED)        return -1;
-               if(!CheckMem(Data, sizeof(Uint16)))     return -1;
+               if(!Data)       LEAVE_RET('i', conn->RemotePort);
+               if(conn->State != TCP_ST_CLOSED)        LEAVE_RET('i', -1);
+               if(!CheckMem(Data, sizeof(Uint16)))     LEAVE_RET('i', -1);
                conn->RemotePort = *(Uint16*)Data;
-               return 0;
+               LEAVE_RET('i', conn->RemotePort);
 
        case 6: // Set Remote IP
                if( conn->State != TCP_ST_CLOSED )
-                       return -1;
+                       LEAVE_RET('i', -1);
                if( conn->Interface->Type == 4 )
                {
-                       if(!CheckMem(Data, sizeof(tIPv4)))      return -1;
+                       if(!CheckMem(Data, sizeof(tIPv4)))      LEAVE_RET('i', -1);
                        conn->RemoteIP.v4 = *(tIPv4*)Data;
                }
                else if( conn->Interface->Type == 6 )
                {
-                       if(!CheckMem(Data, sizeof(tIPv6)))      return -1;
+                       if(!CheckMem(Data, sizeof(tIPv6)))      LEAVE_RET('i', -1);
                        conn->RemoteIP.v6 = *(tIPv6*)Data;
                }
-               return 0;
+               LEAVE_RET('i', 0);
 
        case 7: // Connect
-               if(conn->LocalPort == -1)
+               if(conn->LocalPort == 0xFFFF)
                        conn->LocalPort = TCP_GetUnusedPort();
                if(conn->RemotePort == -1)
-                       return 0;
+                       LEAVE_RET('i', 0);
 
-               TCP_StartConnection(conn);
-               return 1;
+               {
+                       tTime   timeout_end = now() + conn->Interface->TimeoutDelay;
+       
+                       TCP_StartConnection(conn);
+                       // TODO: Wait for connection to open
+                       while( conn->State == TCP_ST_SYN_SENT && timeout_end > now() ) {
+                               Threads_Yield();
+                       }
+                       if( conn->State == TCP_ST_SYN_SENT )
+                               LEAVE_RET('i', 0);
+               }
+
+               LEAVE_RET('i', 1);
+       
+       // Get recieve buffer length
+       case 8:
+               LEAVE_RET('i', conn->RecievedBuffer->Length);
        }
 
        return 0;
@@ -551,5 +1264,78 @@ int TCP_Client_IOCtl(tVFS_Node *Node, int ID, void *Data)
 
 void TCP_Client_Close(tVFS_Node *Node)
 {
-       free(Node->ImplPtr);
+       tTCPConnection  *conn = Node->ImplPtr;
+       tTCPHeader      packet;
+       
+       ENTER("pNode", Node);
+       
+       if( conn->State == TCP_ST_CLOSE_WAIT || conn->State == TCP_ST_OPEN )
+       {
+               packet.SourcePort = htons(conn->LocalPort);
+               packet.DestPort = htons(conn->RemotePort);
+               packet.DataOffset = (sizeof(tTCPHeader)/4)*16;
+               packet.WindowSize = TCP_WINDOW_SIZE;
+               
+               packet.AcknowlegementNumber = 0;
+               packet.SequenceNumber = htonl(conn->NextSequenceSend);
+               packet.Flags = TCP_FLAG_FIN;
+               
+               TCP_SendPacket( conn, sizeof(tTCPHeader), &packet );
+       }
+       
+       switch( conn->State )
+       {
+       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();
+               break;
+       default:
+               Log_Warning("TCP", "Unhandled connection state in TCP_Client_Close");
+               break;
+       }
+       
+       free(conn);
+       
+       LEAVE('-');
+}
+
+/**
+ * \brief Checks if a value is between two others (after taking into account wrapping)
+ */
+int WrapBetween(Uint32 Lower, Uint32 Value, Uint32 Higher, Uint32 MaxValue)
+{
+       if( MaxValue < 0xFFFFFFFF )
+       {
+               Lower %= MaxValue + 1;
+               Value %= MaxValue + 1;
+               Higher %= MaxValue + 1;
+       }
+       
+       // Simple Case, no wrap ?
+       //       Lower Value Higher
+       // | ... + ... + ... + ... |
+
+       if( Lower < Higher ) {
+               return Lower < Value && Value < Higher;
+       }
+       // Higher has wrapped below lower
+       
+       // Value > Lower ?
+       //       Higher Lower Value
+       // | ... +  ... + ... + ... |
+       if( Value > Lower ) {
+               return 1;
+       }
+       
+       // Value < Higher ?
+       //       Value Higher Lower
+       // | ... + ... +  ... + ... |
+       if( Value < Higher ) {
+               return 1;
+       }
+       
+       return 0;
 }

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