diff options
author | Dean Camera <dean@fourwalledcubicle.com> | 2010-05-08 03:12:14 +0000 |
---|---|---|
committer | Dean Camera <dean@fourwalledcubicle.com> | 2010-05-08 03:12:14 +0000 |
commit | 071e02c6b6b4837fa9cf0b6d4c749994e02638d7 (patch) | |
tree | 960446788703b69f0bb285450be80c5b3d8cc22c /Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c | |
parent | e331b531c6e6d93eb0eee42b9002074e8090ad18 (diff) | |
download | lufa-071e02c6b6b4837fa9cf0b6d4c749994e02638d7.tar.gz lufa-071e02c6b6b4837fa9cf0b6d4c749994e02638d7.tar.bz2 lufa-071e02c6b6b4837fa9cf0b6d4c749994e02638d7.zip |
Add svn:eol-style property to source files, so that the line endings are correctly converted to the target system's native end of line style.
Diffstat (limited to 'Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c')
-rw-r--r-- | Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c | 1236 |
1 files changed, 618 insertions, 618 deletions
diff --git a/Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c b/Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c index 74d3a78c3..8ec8fca1d 100644 --- a/Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c +++ b/Demos/Device/LowLevel/RNDISEthernet/Lib/TCP.c @@ -1,618 +1,618 @@ -/*
- LUFA Library
- Copyright (C) Dean Camera, 2010.
-
- dean [at] fourwalledcubicle [dot] com
- www.fourwalledcubicle.com
-*/
-
-/*
- Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com)
-
- Permission to use, copy, modify, distribute, and sell this
- software and its documentation for any purpose is hereby granted
- without fee, provided that the above copyright notice appear in
- all copies and that both that the copyright notice and this
- permission notice and warranty disclaimer appear in supporting
- documentation, and that the name of the author not be used in
- advertising or publicity pertaining to distribution of the
- software without specific, written prior permission.
-
- The author disclaim all warranties with regard to this
- software, including all implied warranties of merchantability
- and fitness. In no event shall the author be liable for any
- special, indirect or consequential damages or any damages
- whatsoever resulting from loss of use, data or profits, whether
- in an action of contract, negligence or other tortious action,
- arising out of or in connection with the use or performance of
- this software.
-*/
-
-/** \file
- *
- * Transmission Control Protocol (TCP) packet handling routines. This protocol handles the reliable in-order transmission
- * and reception of packets to and from devices on a network, to "ports" on the device. It is used in situations where data
- * delivery must be reliable and correct, e.g. HTTP, TELNET and most other non-streaming protocols.
- */
-
-#define INCLUDE_FROM_TCP_C
-#include "TCP.h"
-
-/** Port state table array. This contains the current status of TCP ports in the device. To save on space, only open ports are
- * stored - closed ports may be overwritten at any time, and the system will assume any ports not present in the array are closed. This
- * allows for MAX_OPEN_TCP_PORTS to be less than the number of ports used by the application if desired.
- */
-TCP_PortState_t PortStateTable[MAX_OPEN_TCP_PORTS];
-
-/** Connection state table array. This contains the current status of TCP connections in the device. To save on space, only active
- * (non-closed) connections are stored - closed connections may be overwritten at any time, and the system will assume any connections
- * not present in the array are closed.
- */
-TCP_ConnectionState_t ConnectionStateTable[MAX_TCP_CONNECTIONS];
-
-
-/** Task to handle the calling of each registered application's callback function, to process and generate TCP packets at the application
- * level. If an application produces a response, this task constructs the appropriate Ethernet frame and places it into the Ethernet OUT
- * buffer for later transmission.
- */
-void TCP_Task(void)
-{
- /* Run each application in sequence, to process incoming and generate outgoing packets */
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* Find the corresponding port entry in the port table */
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_OPEN_TCP_PORTS; PTableEntry++)
- {
- /* Run the application handler for the port */
- if ((PortStateTable[PTableEntry].Port == ConnectionStateTable[CSTableEntry].Port) &&
- (PortStateTable[PTableEntry].State == TCP_Port_Open))
- {
- PortStateTable[PTableEntry].ApplicationHandler(&ConnectionStateTable[CSTableEntry],
- &ConnectionStateTable[CSTableEntry].Info.Buffer);
- }
- }
- }
-
- /* Bail out early if there is already a frame waiting to be sent in the Ethernet OUT buffer */
- if (FrameOUT.FrameInBuffer)
- return;
-
- /* Send response packets from each application as the TCP packet buffers are filled by the applications */
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* For each completely received packet, pass it along to the listening application */
- if ((ConnectionStateTable[CSTableEntry].Info.Buffer.Direction == TCP_PACKETDIR_OUT) &&
- (ConnectionStateTable[CSTableEntry].Info.Buffer.Ready))
- {
- Ethernet_Frame_Header_t* FrameOUTHeader = (Ethernet_Frame_Header_t*)&FrameOUT.FrameData;
- IP_Header_t* IPHeaderOUT = (IP_Header_t*)&FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t)];
- TCP_Header_t* TCPHeaderOUT = (TCP_Header_t*)&FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t) +
- sizeof(IP_Header_t)];
- void* TCPDataOUT = &FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t) +
- sizeof(IP_Header_t) +
- sizeof(TCP_Header_t)];
-
- uint16_t PacketSize = ConnectionStateTable[CSTableEntry].Info.Buffer.Length;
-
- /* Fill out the TCP data */
- TCPHeaderOUT->SourcePort = ConnectionStateTable[CSTableEntry].Port;
- TCPHeaderOUT->DestinationPort = ConnectionStateTable[CSTableEntry].RemotePort;
- TCPHeaderOUT->SequenceNumber = SwapEndian_32(ConnectionStateTable[CSTableEntry].Info.SequenceNumberOut);
- TCPHeaderOUT->AcknowledgmentNumber = SwapEndian_32(ConnectionStateTable[CSTableEntry].Info.SequenceNumberIn);
- TCPHeaderOUT->DataOffset = (sizeof(TCP_Header_t) / sizeof(uint32_t));
- TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE);
-
- TCPHeaderOUT->Flags = TCP_FLAG_ACK;
- TCPHeaderOUT->UrgentPointer = 0;
- TCPHeaderOUT->Checksum = 0;
- TCPHeaderOUT->Reserved = 0;
-
- memcpy(TCPDataOUT, ConnectionStateTable[CSTableEntry].Info.Buffer.Data, PacketSize);
-
- ConnectionStateTable[CSTableEntry].Info.SequenceNumberOut += PacketSize;
-
- TCPHeaderOUT->Checksum = TCP_Checksum16(TCPHeaderOUT, ServerIPAddress,
- ConnectionStateTable[CSTableEntry].RemoteAddress,
- (sizeof(TCP_Header_t) + PacketSize));
-
- PacketSize += sizeof(TCP_Header_t);
-
- /* Fill out the response IP header */
- IPHeaderOUT->TotalLength = SwapEndian_16(sizeof(IP_Header_t) + PacketSize);
- IPHeaderOUT->TypeOfService = 0;
- IPHeaderOUT->HeaderLength = (sizeof(IP_Header_t) / sizeof(uint32_t));
- IPHeaderOUT->Version = 4;
- IPHeaderOUT->Flags = 0;
- IPHeaderOUT->FragmentOffset = 0;
- IPHeaderOUT->Identification = 0;
- IPHeaderOUT->HeaderChecksum = 0;
- IPHeaderOUT->Protocol = PROTOCOL_TCP;
- IPHeaderOUT->TTL = DEFAULT_TTL;
- IPHeaderOUT->SourceAddress = ServerIPAddress;
- IPHeaderOUT->DestinationAddress = ConnectionStateTable[CSTableEntry].RemoteAddress;
-
- IPHeaderOUT->HeaderChecksum = Ethernet_Checksum16(IPHeaderOUT, sizeof(IP_Header_t));
-
- PacketSize += sizeof(IP_Header_t);
-
- /* Fill out the response Ethernet frame header */
- FrameOUTHeader->Source = ServerMACAddress;
- FrameOUTHeader->Destination = (MAC_Address_t){{0x02, 0x00, 0x02, 0x00, 0x02, 0x00}};
- FrameOUTHeader->EtherType = SwapEndian_16(ETHERTYPE_IPV4);
-
- PacketSize += sizeof(Ethernet_Frame_Header_t);
-
- /* Set the response length in the buffer and indicate that a response is ready to be sent */
- FrameOUT.FrameLength = PacketSize;
- FrameOUT.FrameInBuffer = true;
-
- ConnectionStateTable[CSTableEntry].Info.Buffer.Ready = false;
-
- break;
- }
- }
-}
-
-/** Initializes the TCP protocol handler, clearing the port and connection state tables. This must be called before TCP packets are
- * processed.
- */
-void TCP_Init(void)
-{
- /* Initialize the port state table with all CLOSED entries */
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_OPEN_TCP_PORTS; PTableEntry++)
- PortStateTable[PTableEntry].State = TCP_Port_Closed;
-
- /* Initialize the connection table with all CLOSED entries */
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- ConnectionStateTable[CSTableEntry].State = TCP_Connection_Closed;
-}
-
-/** Sets the state and callback handler of the given port, specified in big endian to the given state.
- *
- * \param[in] Port Port whose state and callback function to set, specified in big endian
- * \param[in] State New state of the port, a value from the TCP_PortStates_t enum
- * \param[in] Handler Application callback handler for the port
- *
- * \return Boolean true if the port state was set, false otherwise (no more space in the port state table)
- */
-bool TCP_SetPortState(uint16_t Port, uint8_t State, void (*Handler)(TCP_ConnectionState_t*, TCP_ConnectionBuffer_t*))
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- /* Check to see if the port entry is already in the port state table */
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++)
- {
- /* Find existing entry for the port in the table, update it if found */
- if (PortStateTable[PTableEntry].Port == Port)
- {
- PortStateTable[PTableEntry].State = State;
- PortStateTable[PTableEntry].ApplicationHandler = Handler;
- return true;
- }
- }
-
- /* Check if trying to open the port -- if so we need to find an unused (closed) entry and replace it */
- if (State == TCP_Port_Open)
- {
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++)
- {
- /* Find a closed port entry in the table, change it to the given port and state */
- if (PortStateTable[PTableEntry].State == TCP_Port_Closed)
- {
- PortStateTable[PTableEntry].Port = Port;
- PortStateTable[PTableEntry].State = State;
- PortStateTable[PTableEntry].ApplicationHandler = Handler;
- return true;
- }
- }
-
- /* Port not in table and no room to add it, return failure */
- return false;
- }
- else
- {
- /* Port not in table but trying to close it, so operation successful */
- return true;
- }
-}
-
-/** Retrieves the current state of a given TCP port, specified in big endian.
- *
- * \param[in] Port TCP port whose state is to be retrieved, given in big-endian
- *
- * \return A value from the TCP_PortStates_t enum
- */
-uint8_t TCP_GetPortState(uint16_t Port)
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++)
- {
- /* Find existing entry for the port in the table, return the port status if found */
- if (PortStateTable[PTableEntry].Port == Port)
- return PortStateTable[PTableEntry].State;
- }
-
- /* Port not in table, assume closed */
- return TCP_Port_Closed;
-}
-
-/** Sets the connection state of the given port, remote address and remote port to the given TCP connection state. If the
- * connection exists in the connection state table it is updated, otherwise it is created if possible.
- *
- * \param[in] Port TCP port of the connection on the device, specified in big endian
- * \param[in] RemoteAddress Remote protocol IP address of the connected device
- * \param[in] RemotePort TCP port of the remote device in the connection, specified in big endian
- * \param[in] State TCP connection state, a value from the TCP_ConnectionStates_t enum
- *
- * \return Boolean true if the connection was updated or created, false otherwise (no more space in the connection state table)
- */
-bool TCP_SetConnectionState(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort, uint8_t State)
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* Find port entry in the table */
- if ((ConnectionStateTable[CSTableEntry].Port == Port) &&
- IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) &&
- ConnectionStateTable[CSTableEntry].RemotePort == RemotePort)
- {
- ConnectionStateTable[CSTableEntry].State = State;
- return true;
- }
- }
-
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* Find empty entry in the table */
- if (ConnectionStateTable[CSTableEntry].State == TCP_Connection_Closed)
- {
- ConnectionStateTable[CSTableEntry].Port = Port;
- ConnectionStateTable[CSTableEntry].RemoteAddress = RemoteAddress;
- ConnectionStateTable[CSTableEntry].RemotePort = RemotePort;
- ConnectionStateTable[CSTableEntry].State = State;
- return true;
- }
- }
-
- return false;
-}
-
-/** Retrieves the current state of a given TCP connection to a host.
- *
- * \param[in] Port TCP port on the device in the connection, specified in big endian
- * \param[in] RemoteAddress Remote protocol IP address of the connected host
- * \param[in] RemotePort Remote TCP port of the connected host, specified in big endian
- *
- * \return A value from the TCP_ConnectionStates_t enum
- */
-uint8_t TCP_GetConnectionState(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort)
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* Find port entry in the table */
- if ((ConnectionStateTable[CSTableEntry].Port == Port) &&
- IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) &&
- ConnectionStateTable[CSTableEntry].RemotePort == RemotePort)
-
- {
- return ConnectionStateTable[CSTableEntry].State;
- }
- }
-
- return TCP_Connection_Closed;
-}
-
-/** Retrieves the connection info structure of a given connection to a host.
- *
- * \param[in] Port TCP port on the device in the connection, specified in big endian
- * \param[in] RemoteAddress Remote protocol IP address of the connected host
- * \param[in] RemotePort Remote TCP port of the connected host, specified in big endian
- *
- * \return ConnectionInfo structure of the connection if found, NULL otherwise
- */
-TCP_ConnectionInfo_t* TCP_GetConnectionInfo(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort)
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++)
- {
- /* Find port entry in the table */
- if ((ConnectionStateTable[CSTableEntry].Port == Port) &&
- IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) &&
- ConnectionStateTable[CSTableEntry].RemotePort == RemotePort)
- {
- return &ConnectionStateTable[CSTableEntry].Info;
- }
- }
-
- return NULL;
-}
-
-/** Processes a TCP packet inside an Ethernet frame, and writes the appropriate response
- * to the output Ethernet frame if one is created by a application handler.
- *
- * \param[in] IPHeaderInStart Pointer to the start of the incoming packet's IP header
- * \param[in] TCPHeaderInStart Pointer to the start of the incoming packet's TCP header
- * \param[out] TCPHeaderOutStart Pointer to the start of the outgoing packet's TCP header
- *
- * \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE if no
- * response was generated, NO_PROCESS if the packet processing was deferred until the
- * next Ethernet packet handler iteration
- */
-int16_t TCP_ProcessTCPPacket(void* IPHeaderInStart, void* TCPHeaderInStart, void* TCPHeaderOutStart)
-{
- IP_Header_t* IPHeaderIN = (IP_Header_t*)IPHeaderInStart;
- TCP_Header_t* TCPHeaderIN = (TCP_Header_t*)TCPHeaderInStart;
- TCP_Header_t* TCPHeaderOUT = (TCP_Header_t*)TCPHeaderOutStart;
-
- TCP_ConnectionInfo_t* ConnectionInfo;
-
- DecodeTCPHeader(TCPHeaderInStart);
-
- bool PacketResponse = false;
-
- /* Check if the destination port is open and allows incoming connections */
- if (TCP_GetPortState(TCPHeaderIN->DestinationPort) == TCP_Port_Open)
- {
- /* Detect SYN from host to start a connection */
- if (TCPHeaderIN->Flags & TCP_FLAG_SYN)
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort, TCP_Connection_Listen);
-
- /* Detect RST from host to abort existing connection */
- if (TCPHeaderIN->Flags & TCP_FLAG_RST)
- {
- if (TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_Closed))
- {
- TCPHeaderOUT->Flags = (TCP_FLAG_RST | TCP_FLAG_ACK);
- PacketResponse = true;
- }
- }
- else
- {
- /* Process the incoming TCP packet based on the current connection state for the sender and port */
- switch (TCP_GetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort))
- {
- case TCP_Connection_Listen:
- if (TCPHeaderIN->Flags == TCP_FLAG_SYN)
- {
- /* SYN connection starts a connection with a peer */
- if (TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_SYNReceived))
- {
- TCPHeaderOUT->Flags = (TCP_FLAG_SYN | TCP_FLAG_ACK);
-
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort);
-
- ConnectionInfo->SequenceNumberIn = (SwapEndian_32(TCPHeaderIN->SequenceNumber) + 1);
- ConnectionInfo->SequenceNumberOut = 0;
- ConnectionInfo->Buffer.InUse = false;
- }
- else
- {
- TCPHeaderOUT->Flags = TCP_FLAG_RST;
- }
-
- PacketResponse = true;
- }
-
- break;
- case TCP_Connection_SYNReceived:
- if (TCPHeaderIN->Flags == TCP_FLAG_ACK)
- {
- /* ACK during the connection process completes the connection to a peer */
-
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_Established);
-
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- ConnectionInfo->SequenceNumberOut++;
- }
-
- break;
- case TCP_Connection_Established:
- if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK))
- {
- /* FIN ACK when connected to a peer starts the finalization process */
-
- TCPHeaderOUT->Flags = (TCP_FLAG_FIN | TCP_FLAG_ACK);
- PacketResponse = true;
-
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_CloseWait);
-
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- ConnectionInfo->SequenceNumberIn++;
- ConnectionInfo->SequenceNumberOut++;
- }
- else if ((TCPHeaderIN->Flags == TCP_FLAG_ACK) || (TCPHeaderIN->Flags == (TCP_FLAG_ACK | TCP_FLAG_PSH)))
- {
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- /* Check if the buffer is currently in use either by a buffered data to send, or receive */
- if ((ConnectionInfo->Buffer.InUse == false) && (ConnectionInfo->Buffer.Ready == false))
- {
- ConnectionInfo->Buffer.Direction = TCP_PACKETDIR_IN;
- ConnectionInfo->Buffer.InUse = true;
- ConnectionInfo->Buffer.Length = 0;
- }
-
- /* Check if the buffer has been claimed by us to read in data from the peer */
- if ((ConnectionInfo->Buffer.Direction == TCP_PACKETDIR_IN) &&
- (ConnectionInfo->Buffer.Length != TCP_WINDOW_SIZE))
- {
- uint16_t IPOffset = (IPHeaderIN->HeaderLength * sizeof(uint32_t));
- uint16_t TCPOffset = (TCPHeaderIN->DataOffset * sizeof(uint32_t));
- uint16_t DataLength = (SwapEndian_16(IPHeaderIN->TotalLength) - IPOffset - TCPOffset);
-
- /* Copy the packet data into the buffer */
- memcpy(&ConnectionInfo->Buffer.Data[ConnectionInfo->Buffer.Length],
- &((uint8_t*)TCPHeaderInStart)[TCPOffset],
- DataLength);
-
- ConnectionInfo->SequenceNumberIn += DataLength;
- ConnectionInfo->Buffer.Length += DataLength;
-
- /* Check if the buffer is full or if the PSH flag is set, if so indicate buffer ready */
- if ((!(TCP_WINDOW_SIZE - ConnectionInfo->Buffer.Length)) || (TCPHeaderIN->Flags & TCP_FLAG_PSH))
- {
- ConnectionInfo->Buffer.InUse = false;
- ConnectionInfo->Buffer.Ready = true;
-
- TCPHeaderOUT->Flags = TCP_FLAG_ACK;
- PacketResponse = true;
- }
- }
- else
- {
- /* Buffer is currently in use by the application, defer processing of the incoming packet */
- return NO_PROCESS;
- }
- }
-
- break;
- case TCP_Connection_Closing:
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- TCPHeaderOUT->Flags = (TCP_FLAG_ACK | TCP_FLAG_FIN);
- PacketResponse = true;
-
- ConnectionInfo->Buffer.InUse = false;
-
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_FINWait1);
-
- break;
- case TCP_Connection_FINWait1:
- if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK))
- {
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- TCPHeaderOUT->Flags = TCP_FLAG_ACK;
- PacketResponse = true;
-
- ConnectionInfo->SequenceNumberIn++;
- ConnectionInfo->SequenceNumberOut++;
-
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_Closed);
- }
- else if (TCPHeaderIN->Flags == TCP_FLAG_ACK)
- {
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_FINWait2);
- }
-
- break;
- case TCP_Connection_FINWait2:
- if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK))
- {
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- TCPHeaderOUT->Flags = TCP_FLAG_ACK;
- PacketResponse = true;
-
- ConnectionInfo->SequenceNumberIn++;
- ConnectionInfo->SequenceNumberOut++;
-
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_Closed);
- }
-
- break;
- case TCP_Connection_CloseWait:
- if (TCPHeaderIN->Flags == TCP_FLAG_ACK)
- {
- TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort, TCP_Connection_Closed);
- }
-
- break;
- }
- }
- }
- else
- {
- /* Port is not open, indicate via a RST/ACK response to the sender */
- TCPHeaderOUT->Flags = (TCP_FLAG_RST | TCP_FLAG_ACK);
- PacketResponse = true;
- }
-
- /* Check if we need to respond to the sent packet */
- if (PacketResponse)
- {
- ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress,
- TCPHeaderIN->SourcePort);
-
- TCPHeaderOUT->SourcePort = TCPHeaderIN->DestinationPort;
- TCPHeaderOUT->DestinationPort = TCPHeaderIN->SourcePort;
- TCPHeaderOUT->SequenceNumber = SwapEndian_32(ConnectionInfo->SequenceNumberOut);
- TCPHeaderOUT->AcknowledgmentNumber = SwapEndian_32(ConnectionInfo->SequenceNumberIn);
- TCPHeaderOUT->DataOffset = (sizeof(TCP_Header_t) / sizeof(uint32_t));
-
- if (!(ConnectionInfo->Buffer.InUse))
- TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE);
- else
- TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE - ConnectionInfo->Buffer.Length);
-
- TCPHeaderOUT->UrgentPointer = 0;
- TCPHeaderOUT->Checksum = 0;
- TCPHeaderOUT->Reserved = 0;
-
- TCPHeaderOUT->Checksum = TCP_Checksum16(TCPHeaderOUT, IPHeaderIN->DestinationAddress,
- IPHeaderIN->SourceAddress, sizeof(TCP_Header_t));
-
- return sizeof(TCP_Header_t);
- }
-
- return NO_RESPONSE;
-}
-
-/** Calculates the appropriate TCP checksum, consisting of the addition of the one's compliment of each word,
- * complimented.
- *
- * \param[in] TCPHeaderOutStart Pointer to the start of the packet's outgoing TCP header
- * \param[in] SourceAddress Source protocol IP address of the outgoing IP header
- * \param[in] DestinationAddress Destination protocol IP address of the outgoing IP header
- * \param[in] TCPOutSize Size in bytes of the TCP data header and payload
- *
- * \return A 16-bit TCP checksum value
- */
-static uint16_t TCP_Checksum16(void* TCPHeaderOutStart, IP_Address_t SourceAddress,
- IP_Address_t DestinationAddress, uint16_t TCPOutSize)
-{
- uint32_t Checksum = 0;
-
- /* TCP/IP checksums are the addition of the one's compliment of each word including the IP pseudo-header,
- complimented */
-
- Checksum += ((uint16_t*)&SourceAddress)[0];
- Checksum += ((uint16_t*)&SourceAddress)[1];
- Checksum += ((uint16_t*)&DestinationAddress)[0];
- Checksum += ((uint16_t*)&DestinationAddress)[1];
- Checksum += SwapEndian_16(PROTOCOL_TCP);
- Checksum += SwapEndian_16(TCPOutSize);
-
- for (uint8_t CurrWord = 0; CurrWord < (TCPOutSize >> 1); CurrWord++)
- Checksum += ((uint16_t*)TCPHeaderOutStart)[CurrWord];
-
- if (TCPOutSize & 0x01)
- Checksum += (((uint16_t*)TCPHeaderOutStart)[TCPOutSize >> 1] & 0x00FF);
-
- while (Checksum & 0xFFFF0000)
- Checksum = ((Checksum & 0xFFFF) + (Checksum >> 16));
-
- return ~Checksum;
-}
+/* + LUFA Library + Copyright (C) Dean Camera, 2010. + + dean [at] fourwalledcubicle [dot] com + www.fourwalledcubicle.com +*/ + +/* + Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com) + + Permission to use, copy, modify, distribute, and sell this + software and its documentation for any purpose is hereby granted + without fee, provided that the above copyright notice appear in + all copies and that both that the copyright notice and this + permission notice and warranty disclaimer appear in supporting + documentation, and that the name of the author not be used in + advertising or publicity pertaining to distribution of the + software without specific, written prior permission. + + The author disclaim all warranties with regard to this + software, including all implied warranties of merchantability + and fitness. In no event shall the author be liable for any + special, indirect or consequential damages or any damages + whatsoever resulting from loss of use, data or profits, whether + in an action of contract, negligence or other tortious action, + arising out of or in connection with the use or performance of + this software. +*/ + +/** \file + * + * Transmission Control Protocol (TCP) packet handling routines. This protocol handles the reliable in-order transmission + * and reception of packets to and from devices on a network, to "ports" on the device. It is used in situations where data + * delivery must be reliable and correct, e.g. HTTP, TELNET and most other non-streaming protocols. + */ + +#define INCLUDE_FROM_TCP_C +#include "TCP.h" + +/** Port state table array. This contains the current status of TCP ports in the device. To save on space, only open ports are + * stored - closed ports may be overwritten at any time, and the system will assume any ports not present in the array are closed. This + * allows for MAX_OPEN_TCP_PORTS to be less than the number of ports used by the application if desired. + */ +TCP_PortState_t PortStateTable[MAX_OPEN_TCP_PORTS]; + +/** Connection state table array. This contains the current status of TCP connections in the device. To save on space, only active + * (non-closed) connections are stored - closed connections may be overwritten at any time, and the system will assume any connections + * not present in the array are closed. + */ +TCP_ConnectionState_t ConnectionStateTable[MAX_TCP_CONNECTIONS]; + + +/** Task to handle the calling of each registered application's callback function, to process and generate TCP packets at the application + * level. If an application produces a response, this task constructs the appropriate Ethernet frame and places it into the Ethernet OUT + * buffer for later transmission. + */ +void TCP_Task(void) +{ + /* Run each application in sequence, to process incoming and generate outgoing packets */ + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* Find the corresponding port entry in the port table */ + for (uint8_t PTableEntry = 0; PTableEntry < MAX_OPEN_TCP_PORTS; PTableEntry++) + { + /* Run the application handler for the port */ + if ((PortStateTable[PTableEntry].Port == ConnectionStateTable[CSTableEntry].Port) && + (PortStateTable[PTableEntry].State == TCP_Port_Open)) + { + PortStateTable[PTableEntry].ApplicationHandler(&ConnectionStateTable[CSTableEntry], + &ConnectionStateTable[CSTableEntry].Info.Buffer); + } + } + } + + /* Bail out early if there is already a frame waiting to be sent in the Ethernet OUT buffer */ + if (FrameOUT.FrameInBuffer) + return; + + /* Send response packets from each application as the TCP packet buffers are filled by the applications */ + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* For each completely received packet, pass it along to the listening application */ + if ((ConnectionStateTable[CSTableEntry].Info.Buffer.Direction == TCP_PACKETDIR_OUT) && + (ConnectionStateTable[CSTableEntry].Info.Buffer.Ready)) + { + Ethernet_Frame_Header_t* FrameOUTHeader = (Ethernet_Frame_Header_t*)&FrameOUT.FrameData; + IP_Header_t* IPHeaderOUT = (IP_Header_t*)&FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t)]; + TCP_Header_t* TCPHeaderOUT = (TCP_Header_t*)&FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t) + + sizeof(IP_Header_t)]; + void* TCPDataOUT = &FrameOUT.FrameData[sizeof(Ethernet_Frame_Header_t) + + sizeof(IP_Header_t) + + sizeof(TCP_Header_t)]; + + uint16_t PacketSize = ConnectionStateTable[CSTableEntry].Info.Buffer.Length; + + /* Fill out the TCP data */ + TCPHeaderOUT->SourcePort = ConnectionStateTable[CSTableEntry].Port; + TCPHeaderOUT->DestinationPort = ConnectionStateTable[CSTableEntry].RemotePort; + TCPHeaderOUT->SequenceNumber = SwapEndian_32(ConnectionStateTable[CSTableEntry].Info.SequenceNumberOut); + TCPHeaderOUT->AcknowledgmentNumber = SwapEndian_32(ConnectionStateTable[CSTableEntry].Info.SequenceNumberIn); + TCPHeaderOUT->DataOffset = (sizeof(TCP_Header_t) / sizeof(uint32_t)); + TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE); + + TCPHeaderOUT->Flags = TCP_FLAG_ACK; + TCPHeaderOUT->UrgentPointer = 0; + TCPHeaderOUT->Checksum = 0; + TCPHeaderOUT->Reserved = 0; + + memcpy(TCPDataOUT, ConnectionStateTable[CSTableEntry].Info.Buffer.Data, PacketSize); + + ConnectionStateTable[CSTableEntry].Info.SequenceNumberOut += PacketSize; + + TCPHeaderOUT->Checksum = TCP_Checksum16(TCPHeaderOUT, ServerIPAddress, + ConnectionStateTable[CSTableEntry].RemoteAddress, + (sizeof(TCP_Header_t) + PacketSize)); + + PacketSize += sizeof(TCP_Header_t); + + /* Fill out the response IP header */ + IPHeaderOUT->TotalLength = SwapEndian_16(sizeof(IP_Header_t) + PacketSize); + IPHeaderOUT->TypeOfService = 0; + IPHeaderOUT->HeaderLength = (sizeof(IP_Header_t) / sizeof(uint32_t)); + IPHeaderOUT->Version = 4; + IPHeaderOUT->Flags = 0; + IPHeaderOUT->FragmentOffset = 0; + IPHeaderOUT->Identification = 0; + IPHeaderOUT->HeaderChecksum = 0; + IPHeaderOUT->Protocol = PROTOCOL_TCP; + IPHeaderOUT->TTL = DEFAULT_TTL; + IPHeaderOUT->SourceAddress = ServerIPAddress; + IPHeaderOUT->DestinationAddress = ConnectionStateTable[CSTableEntry].RemoteAddress; + + IPHeaderOUT->HeaderChecksum = Ethernet_Checksum16(IPHeaderOUT, sizeof(IP_Header_t)); + + PacketSize += sizeof(IP_Header_t); + + /* Fill out the response Ethernet frame header */ + FrameOUTHeader->Source = ServerMACAddress; + FrameOUTHeader->Destination = (MAC_Address_t){{0x02, 0x00, 0x02, 0x00, 0x02, 0x00}}; + FrameOUTHeader->EtherType = SwapEndian_16(ETHERTYPE_IPV4); + + PacketSize += sizeof(Ethernet_Frame_Header_t); + + /* Set the response length in the buffer and indicate that a response is ready to be sent */ + FrameOUT.FrameLength = PacketSize; + FrameOUT.FrameInBuffer = true; + + ConnectionStateTable[CSTableEntry].Info.Buffer.Ready = false; + + break; + } + } +} + +/** Initializes the TCP protocol handler, clearing the port and connection state tables. This must be called before TCP packets are + * processed. + */ +void TCP_Init(void) +{ + /* Initialize the port state table with all CLOSED entries */ + for (uint8_t PTableEntry = 0; PTableEntry < MAX_OPEN_TCP_PORTS; PTableEntry++) + PortStateTable[PTableEntry].State = TCP_Port_Closed; + + /* Initialize the connection table with all CLOSED entries */ + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + ConnectionStateTable[CSTableEntry].State = TCP_Connection_Closed; +} + +/** Sets the state and callback handler of the given port, specified in big endian to the given state. + * + * \param[in] Port Port whose state and callback function to set, specified in big endian + * \param[in] State New state of the port, a value from the TCP_PortStates_t enum + * \param[in] Handler Application callback handler for the port + * + * \return Boolean true if the port state was set, false otherwise (no more space in the port state table) + */ +bool TCP_SetPortState(uint16_t Port, uint8_t State, void (*Handler)(TCP_ConnectionState_t*, TCP_ConnectionBuffer_t*)) +{ + /* Note, Port number should be specified in BIG endian to simplify network code */ + + /* Check to see if the port entry is already in the port state table */ + for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++) + { + /* Find existing entry for the port in the table, update it if found */ + if (PortStateTable[PTableEntry].Port == Port) + { + PortStateTable[PTableEntry].State = State; + PortStateTable[PTableEntry].ApplicationHandler = Handler; + return true; + } + } + + /* Check if trying to open the port -- if so we need to find an unused (closed) entry and replace it */ + if (State == TCP_Port_Open) + { + for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++) + { + /* Find a closed port entry in the table, change it to the given port and state */ + if (PortStateTable[PTableEntry].State == TCP_Port_Closed) + { + PortStateTable[PTableEntry].Port = Port; + PortStateTable[PTableEntry].State = State; + PortStateTable[PTableEntry].ApplicationHandler = Handler; + return true; + } + } + + /* Port not in table and no room to add it, return failure */ + return false; + } + else + { + /* Port not in table but trying to close it, so operation successful */ + return true; + } +} + +/** Retrieves the current state of a given TCP port, specified in big endian. + * + * \param[in] Port TCP port whose state is to be retrieved, given in big-endian + * + * \return A value from the TCP_PortStates_t enum + */ +uint8_t TCP_GetPortState(uint16_t Port) +{ + /* Note, Port number should be specified in BIG endian to simplify network code */ + + for (uint8_t PTableEntry = 0; PTableEntry < MAX_TCP_CONNECTIONS; PTableEntry++) + { + /* Find existing entry for the port in the table, return the port status if found */ + if (PortStateTable[PTableEntry].Port == Port) + return PortStateTable[PTableEntry].State; + } + + /* Port not in table, assume closed */ + return TCP_Port_Closed; +} + +/** Sets the connection state of the given port, remote address and remote port to the given TCP connection state. If the + * connection exists in the connection state table it is updated, otherwise it is created if possible. + * + * \param[in] Port TCP port of the connection on the device, specified in big endian + * \param[in] RemoteAddress Remote protocol IP address of the connected device + * \param[in] RemotePort TCP port of the remote device in the connection, specified in big endian + * \param[in] State TCP connection state, a value from the TCP_ConnectionStates_t enum + * + * \return Boolean true if the connection was updated or created, false otherwise (no more space in the connection state table) + */ +bool TCP_SetConnectionState(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort, uint8_t State) +{ + /* Note, Port number should be specified in BIG endian to simplify network code */ + + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* Find port entry in the table */ + if ((ConnectionStateTable[CSTableEntry].Port == Port) && + IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) && + ConnectionStateTable[CSTableEntry].RemotePort == RemotePort) + { + ConnectionStateTable[CSTableEntry].State = State; + return true; + } + } + + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* Find empty entry in the table */ + if (ConnectionStateTable[CSTableEntry].State == TCP_Connection_Closed) + { + ConnectionStateTable[CSTableEntry].Port = Port; + ConnectionStateTable[CSTableEntry].RemoteAddress = RemoteAddress; + ConnectionStateTable[CSTableEntry].RemotePort = RemotePort; + ConnectionStateTable[CSTableEntry].State = State; + return true; + } + } + + return false; +} + +/** Retrieves the current state of a given TCP connection to a host. + * + * \param[in] Port TCP port on the device in the connection, specified in big endian + * \param[in] RemoteAddress Remote protocol IP address of the connected host + * \param[in] RemotePort Remote TCP port of the connected host, specified in big endian + * + * \return A value from the TCP_ConnectionStates_t enum + */ +uint8_t TCP_GetConnectionState(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort) +{ + /* Note, Port number should be specified in BIG endian to simplify network code */ + + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* Find port entry in the table */ + if ((ConnectionStateTable[CSTableEntry].Port == Port) && + IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) && + ConnectionStateTable[CSTableEntry].RemotePort == RemotePort) + + { + return ConnectionStateTable[CSTableEntry].State; + } + } + + return TCP_Connection_Closed; +} + +/** Retrieves the connection info structure of a given connection to a host. + * + * \param[in] Port TCP port on the device in the connection, specified in big endian + * \param[in] RemoteAddress Remote protocol IP address of the connected host + * \param[in] RemotePort Remote TCP port of the connected host, specified in big endian + * + * \return ConnectionInfo structure of the connection if found, NULL otherwise + */ +TCP_ConnectionInfo_t* TCP_GetConnectionInfo(uint16_t Port, IP_Address_t RemoteAddress, uint16_t RemotePort) +{ + /* Note, Port number should be specified in BIG endian to simplify network code */ + + for (uint8_t CSTableEntry = 0; CSTableEntry < MAX_TCP_CONNECTIONS; CSTableEntry++) + { + /* Find port entry in the table */ + if ((ConnectionStateTable[CSTableEntry].Port == Port) && + IP_COMPARE(&ConnectionStateTable[CSTableEntry].RemoteAddress, &RemoteAddress) && + ConnectionStateTable[CSTableEntry].RemotePort == RemotePort) + { + return &ConnectionStateTable[CSTableEntry].Info; + } + } + + return NULL; +} + +/** Processes a TCP packet inside an Ethernet frame, and writes the appropriate response + * to the output Ethernet frame if one is created by a application handler. + * + * \param[in] IPHeaderInStart Pointer to the start of the incoming packet's IP header + * \param[in] TCPHeaderInStart Pointer to the start of the incoming packet's TCP header + * \param[out] TCPHeaderOutStart Pointer to the start of the outgoing packet's TCP header + * + * \return The number of bytes written to the out Ethernet frame if any, NO_RESPONSE if no + * response was generated, NO_PROCESS if the packet processing was deferred until the + * next Ethernet packet handler iteration + */ +int16_t TCP_ProcessTCPPacket(void* IPHeaderInStart, void* TCPHeaderInStart, void* TCPHeaderOutStart) +{ + IP_Header_t* IPHeaderIN = (IP_Header_t*)IPHeaderInStart; + TCP_Header_t* TCPHeaderIN = (TCP_Header_t*)TCPHeaderInStart; + TCP_Header_t* TCPHeaderOUT = (TCP_Header_t*)TCPHeaderOutStart; + + TCP_ConnectionInfo_t* ConnectionInfo; + + DecodeTCPHeader(TCPHeaderInStart); + + bool PacketResponse = false; + + /* Check if the destination port is open and allows incoming connections */ + if (TCP_GetPortState(TCPHeaderIN->DestinationPort) == TCP_Port_Open) + { + /* Detect SYN from host to start a connection */ + if (TCPHeaderIN->Flags & TCP_FLAG_SYN) + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort, TCP_Connection_Listen); + + /* Detect RST from host to abort existing connection */ + if (TCPHeaderIN->Flags & TCP_FLAG_RST) + { + if (TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_Closed)) + { + TCPHeaderOUT->Flags = (TCP_FLAG_RST | TCP_FLAG_ACK); + PacketResponse = true; + } + } + else + { + /* Process the incoming TCP packet based on the current connection state for the sender and port */ + switch (TCP_GetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort)) + { + case TCP_Connection_Listen: + if (TCPHeaderIN->Flags == TCP_FLAG_SYN) + { + /* SYN connection starts a connection with a peer */ + if (TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_SYNReceived)) + { + TCPHeaderOUT->Flags = (TCP_FLAG_SYN | TCP_FLAG_ACK); + + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, TCPHeaderIN->SourcePort); + + ConnectionInfo->SequenceNumberIn = (SwapEndian_32(TCPHeaderIN->SequenceNumber) + 1); + ConnectionInfo->SequenceNumberOut = 0; + ConnectionInfo->Buffer.InUse = false; + } + else + { + TCPHeaderOUT->Flags = TCP_FLAG_RST; + } + + PacketResponse = true; + } + + break; + case TCP_Connection_SYNReceived: + if (TCPHeaderIN->Flags == TCP_FLAG_ACK) + { + /* ACK during the connection process completes the connection to a peer */ + + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_Established); + + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + ConnectionInfo->SequenceNumberOut++; + } + + break; + case TCP_Connection_Established: + if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK)) + { + /* FIN ACK when connected to a peer starts the finalization process */ + + TCPHeaderOUT->Flags = (TCP_FLAG_FIN | TCP_FLAG_ACK); + PacketResponse = true; + + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_CloseWait); + + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + ConnectionInfo->SequenceNumberIn++; + ConnectionInfo->SequenceNumberOut++; + } + else if ((TCPHeaderIN->Flags == TCP_FLAG_ACK) || (TCPHeaderIN->Flags == (TCP_FLAG_ACK | TCP_FLAG_PSH))) + { + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + /* Check if the buffer is currently in use either by a buffered data to send, or receive */ + if ((ConnectionInfo->Buffer.InUse == false) && (ConnectionInfo->Buffer.Ready == false)) + { + ConnectionInfo->Buffer.Direction = TCP_PACKETDIR_IN; + ConnectionInfo->Buffer.InUse = true; + ConnectionInfo->Buffer.Length = 0; + } + + /* Check if the buffer has been claimed by us to read in data from the peer */ + if ((ConnectionInfo->Buffer.Direction == TCP_PACKETDIR_IN) && + (ConnectionInfo->Buffer.Length != TCP_WINDOW_SIZE)) + { + uint16_t IPOffset = (IPHeaderIN->HeaderLength * sizeof(uint32_t)); + uint16_t TCPOffset = (TCPHeaderIN->DataOffset * sizeof(uint32_t)); + uint16_t DataLength = (SwapEndian_16(IPHeaderIN->TotalLength) - IPOffset - TCPOffset); + + /* Copy the packet data into the buffer */ + memcpy(&ConnectionInfo->Buffer.Data[ConnectionInfo->Buffer.Length], + &((uint8_t*)TCPHeaderInStart)[TCPOffset], + DataLength); + + ConnectionInfo->SequenceNumberIn += DataLength; + ConnectionInfo->Buffer.Length += DataLength; + + /* Check if the buffer is full or if the PSH flag is set, if so indicate buffer ready */ + if ((!(TCP_WINDOW_SIZE - ConnectionInfo->Buffer.Length)) || (TCPHeaderIN->Flags & TCP_FLAG_PSH)) + { + ConnectionInfo->Buffer.InUse = false; + ConnectionInfo->Buffer.Ready = true; + + TCPHeaderOUT->Flags = TCP_FLAG_ACK; + PacketResponse = true; + } + } + else + { + /* Buffer is currently in use by the application, defer processing of the incoming packet */ + return NO_PROCESS; + } + } + + break; + case TCP_Connection_Closing: + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + TCPHeaderOUT->Flags = (TCP_FLAG_ACK | TCP_FLAG_FIN); + PacketResponse = true; + + ConnectionInfo->Buffer.InUse = false; + + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_FINWait1); + + break; + case TCP_Connection_FINWait1: + if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK)) + { + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + TCPHeaderOUT->Flags = TCP_FLAG_ACK; + PacketResponse = true; + + ConnectionInfo->SequenceNumberIn++; + ConnectionInfo->SequenceNumberOut++; + + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_Closed); + } + else if (TCPHeaderIN->Flags == TCP_FLAG_ACK) + { + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_FINWait2); + } + + break; + case TCP_Connection_FINWait2: + if (TCPHeaderIN->Flags == (TCP_FLAG_FIN | TCP_FLAG_ACK)) + { + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + TCPHeaderOUT->Flags = TCP_FLAG_ACK; + PacketResponse = true; + + ConnectionInfo->SequenceNumberIn++; + ConnectionInfo->SequenceNumberOut++; + + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_Closed); + } + + break; + case TCP_Connection_CloseWait: + if (TCPHeaderIN->Flags == TCP_FLAG_ACK) + { + TCP_SetConnectionState(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort, TCP_Connection_Closed); + } + + break; + } + } + } + else + { + /* Port is not open, indicate via a RST/ACK response to the sender */ + TCPHeaderOUT->Flags = (TCP_FLAG_RST | TCP_FLAG_ACK); + PacketResponse = true; + } + + /* Check if we need to respond to the sent packet */ + if (PacketResponse) + { + ConnectionInfo = TCP_GetConnectionInfo(TCPHeaderIN->DestinationPort, IPHeaderIN->SourceAddress, + TCPHeaderIN->SourcePort); + + TCPHeaderOUT->SourcePort = TCPHeaderIN->DestinationPort; + TCPHeaderOUT->DestinationPort = TCPHeaderIN->SourcePort; + TCPHeaderOUT->SequenceNumber = SwapEndian_32(ConnectionInfo->SequenceNumberOut); + TCPHeaderOUT->AcknowledgmentNumber = SwapEndian_32(ConnectionInfo->SequenceNumberIn); + TCPHeaderOUT->DataOffset = (sizeof(TCP_Header_t) / sizeof(uint32_t)); + + if (!(ConnectionInfo->Buffer.InUse)) + TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE); + else + TCPHeaderOUT->WindowSize = SwapEndian_16(TCP_WINDOW_SIZE - ConnectionInfo->Buffer.Length); + + TCPHeaderOUT->UrgentPointer = 0; + TCPHeaderOUT->Checksum = 0; + TCPHeaderOUT->Reserved = 0; + + TCPHeaderOUT->Checksum = TCP_Checksum16(TCPHeaderOUT, IPHeaderIN->DestinationAddress, + IPHeaderIN->SourceAddress, sizeof(TCP_Header_t)); + + return sizeof(TCP_Header_t); + } + + return NO_RESPONSE; +} + +/** Calculates the appropriate TCP checksum, consisting of the addition of the one's compliment of each word, + * complimented. + * + * \param[in] TCPHeaderOutStart Pointer to the start of the packet's outgoing TCP header + * \param[in] SourceAddress Source protocol IP address of the outgoing IP header + * \param[in] DestinationAddress Destination protocol IP address of the outgoing IP header + * \param[in] TCPOutSize Size in bytes of the TCP data header and payload + * + * \return A 16-bit TCP checksum value + */ +static uint16_t TCP_Checksum16(void* TCPHeaderOutStart, IP_Address_t SourceAddress, + IP_Address_t DestinationAddress, uint16_t TCPOutSize) +{ + uint32_t Checksum = 0; + + /* TCP/IP checksums are the addition of the one's compliment of each word including the IP pseudo-header, + complimented */ + + Checksum += ((uint16_t*)&SourceAddress)[0]; + Checksum += ((uint16_t*)&SourceAddress)[1]; + Checksum += ((uint16_t*)&DestinationAddress)[0]; + Checksum += ((uint16_t*)&DestinationAddress)[1]; + Checksum += SwapEndian_16(PROTOCOL_TCP); + Checksum += SwapEndian_16(TCPOutSize); + + for (uint8_t CurrWord = 0; CurrWord < (TCPOutSize >> 1); CurrWord++) + Checksum += ((uint16_t*)TCPHeaderOutStart)[CurrWord]; + + if (TCPOutSize & 0x01) + Checksum += (((uint16_t*)TCPHeaderOutStart)[TCPOutSize >> 1] & 0x00FF); + + while (Checksum & 0xFFFF0000) + Checksum = ((Checksum & 0xFFFF) + (Checksum >> 16)); + + return ~Checksum; +} |