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254 lines
11 KiB
C
254 lines
11 KiB
C
8 years ago
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/*
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* FreeRTOS+TCP Labs Build 160919 (C) 2016 Real Time Engineers ltd.
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* Authors include Hein Tibosch and Richard Barry
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*
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*******************************************************************************
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***** NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ***
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*** ***
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*** ***
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*** FREERTOS+TCP IS STILL IN THE LAB (mainly because the FTP and HTTP ***
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*** demos have a dependency on FreeRTOS+FAT, which is only in the Labs ***
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*** download): ***
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*** ***
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*** FreeRTOS+TCP is functional and has been used in commercial products ***
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*** for some time. Be aware however that we are still refining its ***
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*** design, the source code does not yet quite conform to the strict ***
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*** coding and style standards mandated by Real Time Engineers ltd., and ***
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*** the documentation and testing is not necessarily complete. ***
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*** ***
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*** PLEASE REPORT EXPERIENCES USING THE SUPPORT RESOURCES FOUND ON THE ***
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*** URL: http://www.FreeRTOS.org/contact Active early adopters may, at ***
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*** the sole discretion of Real Time Engineers Ltd., be offered versions ***
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*** under a license other than that described below. ***
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*** ***
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*** ***
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***** NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ******* NOTE ***
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*******************************************************************************
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*
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* FreeRTOS+TCP can be used under two different free open source licenses. The
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* license that applies is dependent on the processor on which FreeRTOS+TCP is
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* executed, as follows:
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*
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* If FreeRTOS+TCP is executed on one of the processors listed under the Special
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* License Arrangements heading of the FreeRTOS+TCP license information web
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* page, then it can be used under the terms of the FreeRTOS Open Source
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* License. If FreeRTOS+TCP is used on any other processor, then it can be used
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* under the terms of the GNU General Public License V2. Links to the relevant
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* licenses follow:
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*
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* The FreeRTOS+TCP License Information Page: http://www.FreeRTOS.org/tcp_license
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* The FreeRTOS Open Source License: http://www.FreeRTOS.org/license
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* The GNU General Public License Version 2: http://www.FreeRTOS.org/gpl-2.0.txt
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*
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* FreeRTOS+TCP is distributed in the hope that it will be useful. You cannot
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* use FreeRTOS+TCP unless you agree that you use the software 'as is'.
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* FreeRTOS+TCP is provided WITHOUT ANY WARRANTY; without even the implied
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* warranties of NON-INFRINGEMENT, MERCHANTABILITY or FITNESS FOR A PARTICULAR
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* PURPOSE. Real Time Engineers Ltd. disclaims all conditions and terms, be they
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* implied, expressed, or statutory.
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*
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* 1 tab == 4 spaces!
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*
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* http://www.FreeRTOS.org
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* http://www.FreeRTOS.org/plus
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* http://www.FreeRTOS.org/labs
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*
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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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extern BaseType_t xTCPWindowLoggingLevel;
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typedef struct xTCPTimer
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{
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uint32_t ulBorn;
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} TCPTimer_t;
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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;
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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 xListItem; /* 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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typedef struct xTCP_WINSIZE
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{
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uint32_t ulRxWindowLength;
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uint32_t ulTxWindowLength;
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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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#if( ipconfigUSE_TCP_TIMESTAMPS == 1 )
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#define ipSIZE_TCP_OPTIONS ( 16u + 12u )
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#else
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#define ipSIZE_TCP_OPTIONS 16u
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#endif
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#else
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#if ipconfigUSE_TCP_TIMESTAMPS == 1
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#define ipSIZE_TCP_OPTIONS ( 12u + 12u )
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#else
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#define ipSIZE_TCP_OPTIONS 12u
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#endif
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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;
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TCPWinSize_t xSize;
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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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#if( ipconfigUSE_TCP_TIMESTAMPS == 1 )
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uint32_t ulTimeStamp; /* The value of the TCP timestamp, transmitted or received */
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#endif
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} rx, tx;
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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, uint32_t ulRxWindowLength,
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uint32_t ulTxWindowLength, uint32_t ulAckNumber, uint32_t ulSequenceNumber, 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 *pxWindow );
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/* Initialize a window */
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void vTCPWindowInit( TCPWindow_t *pxWindow, uint32_t ulAckNumber, uint32_t ulSequenceNumber, uint32_t ulMSS );
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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, uint32_t ulSequenceNumber, uint32_t ulLength, uint32_t ulSpace );
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/* When lTCPWindowRxCheck returned false, please call store for this unexpected data */
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BaseType_t xTCPWindowRxStore( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength );
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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( TCPWindow_t *pxWindow );
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/* _HT_ Temporary function for testing/debugging
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* Not used at this moment */
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void vTCPWinShowSegments( TCPWindow_t *pxWindow, BaseType_t bForRx );
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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, uint32_t ulLength, int32_t lPosition, 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 *pxWindow, uint32_t ulWindowSize, 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( TCPWindow_t *pxWindow );
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/* Fetches data to be sent.
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* apPos will point to a location with the circular data buffer: txStream */
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uint32_t ulTCPWindowTxGet( TCPWindow_t *pxWindow, uint32_t ulWindowSize, int32_t *plPosition );
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/* Receive a normal ACK */
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uint32_t ulTCPWindowTxAck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber );
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/* Receive a SACK option */
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uint32_t ulTCPWindowTxSack( TCPWindow_t *pxWindow, uint32_t ulFirst, 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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