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238 lines
12 KiB
C
238 lines
12 KiB
C
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/*
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* FreeRTOS+TCP V2.3.2
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* Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy of
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* this software and associated documentation files (the "Software"), to deal in
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* the Software without restriction, including without limitation the rights to
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* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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* the Software, and to permit persons to whom the Software is furnished to do so,
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* subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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* http://aws.amazon.com/freertos
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* http://www.FreeRTOS.org
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*/
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/*
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* FreeRTOS_TCP_WIN.c
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* Module which handles the TCP windowing schemes for FreeRTOS-PLUS-TCP
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*/
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#ifndef FREERTOS_TCP_WIN_H
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#define FREERTOS_TCP_WIN_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* The name xTCPTimer was already use as the name of an IP-timer.
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*/
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typedef struct xTCPTimerStruct
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{
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uint32_t ulBorn; /**< The time when this timer is created. */
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} TCPTimer_t;
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/**
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* Structure to hold the information about a TCP segment.
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*/
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typedef struct xTCP_SEGMENT
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{
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uint32_t ulSequenceNumber; /**< The sequence number of the first byte in this packet */
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int32_t lMaxLength; /**< Maximum space, number of bytes which can be stored in this segment */
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int32_t lDataLength; /**< Actual number of bytes */
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int32_t lStreamPos; /**< reference to the [t|r]xStream of the socket */
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TCPTimer_t xTransmitTimer; /**< saves a timestamp at the moment this segment gets transmitted (TX only) */
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union
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{
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struct
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{
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uint32_t
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ucTransmitCount : 8, /**< Number of times the segment has been transmitted, used to calculate the RTT */
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ucDupAckCount : 8, /**< Counts the number of times that a higher segment was ACK'd. After 3 times a Fast Retransmission takes place */
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bOutstanding : 1, /**< It the peer's turn, we're just waiting for an ACK */
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bAcked : 1, /**< This segment has been acknowledged */
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bIsForRx : 1; /**< pdTRUE if segment is used for reception */
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} bits;
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uint32_t ulFlags;
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} u; /**< Use a union to store the 32-bit flag field and the breakdown in the same location. */
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#if ( ipconfigUSE_TCP_WIN != 0 )
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struct xLIST_ITEM xQueueItem; /**< TX only: segments can be linked in one of three queues: xPriorityQueue, xTxQueue, and xWaitQueue */
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struct xLIST_ITEM xSegmentItem; /**< With this item the segment can be connected to a list, depending on who is owning it */
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#endif
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} TCPSegment_t;
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/**
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* Structure to store the Rx/Tx window length.
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*/
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typedef struct xTCP_WINSIZE
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{
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uint32_t ulRxWindowLength; /**< The size of the receive window. */
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uint32_t ulTxWindowLength; /**< The size of the send window. */
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} TCPWinSize_t;
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/*
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* If TCP time-stamps are being used, they will occupy 12 bytes in
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* each packet, and thus the message space will become smaller
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*/
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/* Keep this as a multiple of 4 */
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#if ( ipconfigUSE_TCP_WIN == 1 )
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#define ipSIZE_TCP_OPTIONS 16U
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#else
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#define ipSIZE_TCP_OPTIONS 12U
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#endif
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/**
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* Every TCP connection owns a TCP window for the administration of all packets
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* It owns two sets of segment descriptors, incoming and outgoing
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*/
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typedef struct xTCP_WINDOW
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{
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union
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{
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struct
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{
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uint32_t
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bHasInit : 1, /**< The window structure has been initialised */
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bSendFullSize : 1, /**< May only send packets with a size equal to MSS (for optimisation) */
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bTimeStamps : 1; /**< Socket is supposed to use TCP time-stamps. This depends on the */
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} bits; /**< party which opens the connection */
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uint32_t ulFlags;
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} u; /**< Use a union to store the 32-bit flag field and the breakdown at the same place. */
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TCPWinSize_t xSize; /**< Size of the TCP window. */
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struct
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{
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uint32_t ulFirstSequenceNumber; /**< Logging & debug: the first segment received/sent in this connection
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* for Tx: initial send sequence number (ISS)
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* for Rx: initial receive sequence number (IRS) */
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uint32_t ulCurrentSequenceNumber; /**< Tx/Rx: the oldest sequence number not yet confirmed, also SND.UNA / RCV.NXT
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* In other words: the sequence number of the left side of the sliding window */
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uint32_t ulFINSequenceNumber; /**< The sequence number which carried the FIN flag */
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uint32_t ulHighestSequenceNumber; /**< Sequence number of the right-most byte + 1 */
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} rx, /**< Structure for the receiver for TCP. */
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tx; /**< Structure for the transmitter for TCP. */
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uint32_t ulOurSequenceNumber; /**< The SEQ number we're sending out */
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uint32_t ulUserDataLength; /**< Number of bytes in Rx buffer which may be passed to the user, after having received a 'missing packet' */
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uint32_t ulNextTxSequenceNumber; /**< The sequence number given to the next byte to be added for transmission */
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int32_t lSRTT; /**< Smoothed Round Trip Time, it may increment quickly and it decrements slower */
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uint8_t ucOptionLength; /**< Number of valid bytes in ulOptionsData[] */
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#if ( ipconfigUSE_TCP_WIN == 1 )
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List_t xPriorityQueue; /**< Priority queue: segments which must be sent immediately */
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List_t xTxQueue; /**< Transmit queue: segments queued for transmission */
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List_t xWaitQueue; /**< Waiting queue: outstanding segments */
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TCPSegment_t * pxHeadSegment; /**< points to a segment which has not been transmitted and it's size is still growing (user data being added) */
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uint32_t ulOptionsData[ ipSIZE_TCP_OPTIONS / sizeof( uint32_t ) ]; /**< Contains the options we send out */
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List_t xTxSegments; /**< A linked list of all transmission segments, sorted on sequence number */
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List_t xRxSegments; /**< A linked list of reception segments, order depends on sequence of arrival */
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#else
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/* For tiny TCP, there is only 1 outstanding TX segment */
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TCPSegment_t xTxSegment; /**< Priority queue */
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#endif
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uint16_t usOurPortNumber; /**< Mostly for debugging/logging: our TCP port number */
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uint16_t usPeerPortNumber; /**< debugging/logging: the peer's TCP port number */
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uint16_t usMSS; /**< Current accepted MSS */
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uint16_t usMSSInit; /**< MSS as configured by the socket owner */
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} TCPWindow_t;
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/*=============================================================================
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*
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* Creation and destruction
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*
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*=============================================================================*/
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/* Create and initialize a window */
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void vTCPWindowCreate( TCPWindow_t * pxWindow,
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uint32_t ulRxWindowLength,
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uint32_t ulTxWindowLength,
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uint32_t ulAckNumber,
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uint32_t ulSequenceNumber,
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uint32_t ulMSS );
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/* Destroy a window (always returns NULL)
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* It will free some resources: a collection of segments */
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void vTCPWindowDestroy( TCPWindow_t const * pxWindow );
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/* Initialize a window */
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void vTCPWindowInit( TCPWindow_t * pxWindow,
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uint32_t ulAckNumber,
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uint32_t ulSequenceNumber,
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uint32_t ulMSS );
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/* Clean up allocated segments. Should only be called when FreeRTOS+TCP will no longer be used. */
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void vTCPSegmentCleanup( void );
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/*=============================================================================
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*
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* Rx functions
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*
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*=============================================================================*/
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/* if true may be passed directly to user (segment expected and window is empty)
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* But pxWindow->ackno should always be used to set "BUF->ackno" */
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int32_t lTCPWindowRxCheck( TCPWindow_t * pxWindow,
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uint32_t ulSequenceNumber,
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uint32_t ulLength,
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uint32_t ulSpace );
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/* This function will be called as soon as a FIN is received. It will return true
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* if there are no 'open' reception segments */
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BaseType_t xTCPWindowRxEmpty( const TCPWindow_t * pxWindow );
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/*=============================================================================
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*
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* Tx functions
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*
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*=============================================================================*/
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/* Adds data to the Tx-window */
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int32_t lTCPWindowTxAdd( TCPWindow_t * pxWindow,
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uint32_t ulLength,
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int32_t lPosition,
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int32_t lMax );
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/* Check data to be sent and calculate the time period we may sleep */
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BaseType_t xTCPWindowTxHasData( TCPWindow_t const * pxWindow,
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uint32_t ulWindowSize,
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TickType_t * pulDelay );
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/* See if anything is left to be sent
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* Function will be called when a FIN has been received. Only when the TX window is clean,
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* it will return pdTRUE */
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BaseType_t xTCPWindowTxDone( const TCPWindow_t * pxWindow );
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/* Fetches data to be sent.
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* plPosition will point to a location with the circular data buffer: txStream */
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uint32_t ulTCPWindowTxGet( TCPWindow_t * pxWindow,
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uint32_t ulWindowSize,
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int32_t * plPosition );
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/* Receive a normal ACK */
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uint32_t ulTCPWindowTxAck( TCPWindow_t * pxWindow,
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uint32_t ulSequenceNumber );
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/* Receive a SACK option */
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uint32_t ulTCPWindowTxSack( TCPWindow_t * pxWindow,
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uint32_t ulFirst,
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uint32_t ulLast );
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif /* FREERTOS_TCP_WIN_H */
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