+ * \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)
+{
+ 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 ;
+ }
+
+ // Syncronise sequence values
+ if(Header->Flags & TCP_FLAG_SYN) {
+ // 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_Log("TCP", "Conn %p, Sent packet 0x%x ACKed", Connection, Header->AcknowlegementNumber);
+ }
+
+ // Get length of data
+ dataLen = Length - (Header->DataOffset>>4)*4;
+ Log_Log("TCP", "HandleConnectionPacket - dataLen = %i", dataLen);
+
+ //
+ // State Machine
+ //
+ switch( Connection->State )
+ {
+ // 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 )
+ {
+ // TODO: Handle max half-open limit
+ Connection->State = TCP_ST_OPEN;
+ Log_Log("TCP", "Connection fully opened");
+ }
+ 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
+ {
+ 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