+++ /dev/null
-/*
- LUFA Library
- Copyright (C) Dean Camera, 2021.
-
- dean [at] fourwalledcubicle [dot] com
- www.lufa-lib.org
-*/
-
-/*
- Copyright 2021 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 disclaims 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.FrameLength)
- 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;
-
- 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 \ref TCP_PortStates_t enum
- * \param[in] Handler Application callback handler for the port
- *
- * \return Boolean \c true if the port state was set, \c false otherwise (no more space in the port state table)
- */
-bool TCP_SetPortState(const uint16_t Port,
- const 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_OPEN_TCP_PORTS; 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_OPEN_TCP_PORTS; 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 \ref TCP_PortStates_t enum
- */
-uint8_t TCP_GetPortState(const uint16_t Port)
-{
- /* Note, Port number should be specified in BIG endian to simplify network code */
-
- for (uint8_t PTableEntry = 0; PTableEntry < MAX_OPEN_TCP_PORTS; 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 \ref TCP_ConnectionStates_t enum
- *
- * \return Boolean \c true if the connection was updated or created, \c false otherwise (no more space in the connection state table)
- */
-bool TCP_SetConnectionState(const uint16_t Port,
- const IP_Address_t* RemoteAddress,
- const uint16_t RemotePort,
- const 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 \ref TCP_ConnectionStates_t enum
- */
-uint8_t TCP_GetConnectionState(const uint16_t Port,
- const IP_Address_t* RemoteAddress,
- const 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(const uint16_t Port,
- const IP_Address_t* RemoteAddress,
- const 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,
- const IP_Address_t* SourceAddress,
- const 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 (uint16_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;
-}
-
projects / pub / lufa.git / blobdiff