2 * FreeRTOS+TCP V2.0.7
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3 * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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5 * Permission is hereby granted, free of charge, to any person obtaining a copy of
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6 * this software and associated documentation files (the "Software"), to deal in
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7 * the Software without restriction, including without limitation the rights to
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8 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
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9 * the Software, and to permit persons to whom the Software is furnished to do so,
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10 * subject to the following conditions:
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12 * The above copyright notice and this permission notice shall be included in all
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13 * copies or substantial portions of the Software.
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15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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17 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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18 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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19 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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20 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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22 * http://aws.amazon.com/freertos
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23 * http://www.FreeRTOS.org
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27 * FreeRTOS_TCP_WIN.c
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28 * Module which handles the TCP windowing schemes for FreeRTOS-PLUS-TCP
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31 #ifndef FREERTOS_TCP_WIN_H
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32 #define FREERTOS_TCP_WIN_H
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38 extern BaseType_t xTCPWindowLoggingLevel;
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40 typedef struct xTCPTimer
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45 typedef struct xTCP_SEGMENT
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47 uint32_t ulSequenceNumber; /* The sequence number of the first byte in this packet */
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48 int32_t lMaxLength; /* Maximum space, number of bytes which can be stored in this segment */
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49 int32_t lDataLength; /* Actual number of bytes */
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50 int32_t lStreamPos; /* reference to the [t|r]xStream of the socket */
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51 TCPTimer_t xTransmitTimer; /* saves a timestamp at the moment this segment gets transmitted (TX only) */
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57 ucTransmitCount : 8,/* Number of times the segment has been transmitted, used to calculate the RTT */
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58 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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59 bOutstanding : 1, /* It the peer's turn, we're just waiting for an ACK */
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60 bAcked : 1, /* This segment has been acknowledged */
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61 bIsForRx : 1; /* pdTRUE if segment is used for reception */
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65 #if( ipconfigUSE_TCP_WIN != 0 )
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66 struct xLIST_ITEM xQueueItem; /* TX only: segments can be linked in one of three queues: xPriorityQueue, xTxQueue, and xWaitQueue */
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67 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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71 typedef struct xTCP_WINSIZE
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73 uint32_t ulRxWindowLength;
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74 uint32_t ulTxWindowLength;
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78 * If TCP time-stamps are being used, they will occupy 12 bytes in
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79 * each packet, and thus the message space will become smaller
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81 /* Keep this as a multiple of 4 */
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82 #if( ipconfigUSE_TCP_WIN == 1 )
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83 #define ipSIZE_TCP_OPTIONS 16u
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85 #define ipSIZE_TCP_OPTIONS 12u
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89 * Every TCP connection owns a TCP window for the administration of all packets
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90 * It owns two sets of segment descriptors, incoming and outgoing
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92 typedef struct xTCP_WINDOW
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99 bHasInit : 1, /* The window structure has been initialised */
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100 bSendFullSize : 1, /* May only send packets with a size equal to MSS (for optimisation) */
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101 bTimeStamps : 1; /* Socket is supposed to use TCP time-stamps. This depends on the */
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102 } bits; /* party which opens the connection */
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105 TCPWinSize_t xSize;
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108 uint32_t ulFirstSequenceNumber; /* Logging & debug: the first segment received/sent in this connection
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109 * for Tx: initial send sequence number (ISS)
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110 * for Rx: initial receive sequence number (IRS) */
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111 uint32_t ulCurrentSequenceNumber;/* Tx/Rx: the oldest sequence number not yet confirmed, also SND.UNA / RCV.NXT
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112 * In other words: the sequence number of the left side of the sliding window */
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113 uint32_t ulFINSequenceNumber; /* The sequence number which carried the FIN flag */
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114 uint32_t ulHighestSequenceNumber;/* Sequence number of the right-most byte + 1 */
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116 uint32_t ulOurSequenceNumber; /* The SEQ number we're sending out */
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117 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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118 uint32_t ulNextTxSequenceNumber; /* The sequence number given to the next byte to be added for transmission */
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119 int32_t lSRTT; /* Smoothed Round Trip Time, it may increment quickly and it decrements slower */
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120 uint8_t ucOptionLength; /* Number of valid bytes in ulOptionsData[] */
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121 #if( ipconfigUSE_TCP_WIN == 1 )
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122 List_t xPriorityQueue; /* Priority queue: segments which must be sent immediately */
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123 List_t xTxQueue; /* Transmit queue: segments queued for transmission */
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124 List_t xWaitQueue; /* Waiting queue: outstanding segments */
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125 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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126 uint32_t ulOptionsData[ipSIZE_TCP_OPTIONS/sizeof(uint32_t)]; /* Contains the options we send out */
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127 List_t xTxSegments; /* A linked list of all transmission segments, sorted on sequence number */
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128 List_t xRxSegments; /* A linked list of reception segments, order depends on sequence of arrival */
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130 /* For tiny TCP, there is only 1 outstanding TX segment */
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131 TCPSegment_t xTxSegment; /* Priority queue */
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133 uint16_t usOurPortNumber; /* Mostly for debugging/logging: our TCP port number */
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134 uint16_t usPeerPortNumber; /* debugging/logging: the peer's TCP port number */
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135 uint16_t usMSS; /* Current accepted MSS */
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136 uint16_t usMSSInit; /* MSS as configured by the socket owner */
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140 /*=============================================================================
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142 * Creation and destruction
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144 *=============================================================================*/
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146 /* Create and initialize a window */
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147 void vTCPWindowCreate( TCPWindow_t *pxWindow, uint32_t ulRxWindowLength,
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148 uint32_t ulTxWindowLength, uint32_t ulAckNumber, uint32_t ulSequenceNumber, uint32_t ulMSS );
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150 /* Destroy a window (always returns NULL)
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151 * It will free some resources: a collection of segments */
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152 void vTCPWindowDestroy( TCPWindow_t *pxWindow );
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154 /* Initialize a window */
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155 void vTCPWindowInit( TCPWindow_t *pxWindow, uint32_t ulAckNumber, uint32_t ulSequenceNumber, uint32_t ulMSS );
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157 /*=============================================================================
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161 *=============================================================================*/
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163 /* if true may be passed directly to user (segment expected and window is empty)
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164 * But pxWindow->ackno should always be used to set "BUF->ackno" */
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165 int32_t lTCPWindowRxCheck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength, uint32_t ulSpace );
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167 /* When lTCPWindowRxCheck returned false, please call store for this unexpected data */
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168 BaseType_t xTCPWindowRxStore( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength );
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170 /* This function will be called as soon as a FIN is received. It will return true
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171 * if there are no 'open' reception segments */
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172 BaseType_t xTCPWindowRxEmpty( TCPWindow_t *pxWindow );
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174 /* _HT_ Temporary function for testing/debugging
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175 * Not used at this moment */
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176 void vTCPWinShowSegments( TCPWindow_t *pxWindow, BaseType_t bForRx );
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178 /*=============================================================================
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182 *=============================================================================*/
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184 /* Adds data to the Tx-window */
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185 int32_t lTCPWindowTxAdd( TCPWindow_t *pxWindow, uint32_t ulLength, int32_t lPosition, int32_t lMax );
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187 /* Check data to be sent and calculate the time period we may sleep */
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188 BaseType_t xTCPWindowTxHasData( TCPWindow_t *pxWindow, uint32_t ulWindowSize, TickType_t *pulDelay );
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190 /* See if anything is left to be sent
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191 * Function will be called when a FIN has been received. Only when the TX window is clean,
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192 * it will return pdTRUE */
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193 BaseType_t xTCPWindowTxDone( TCPWindow_t *pxWindow );
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195 /* Fetches data to be sent.
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196 * apPos will point to a location with the circular data buffer: txStream */
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197 uint32_t ulTCPWindowTxGet( TCPWindow_t *pxWindow, uint32_t ulWindowSize, int32_t *plPosition );
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199 /* Receive a normal ACK */
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200 uint32_t ulTCPWindowTxAck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber );
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202 /* Receive a SACK option */
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203 uint32_t ulTCPWindowTxSack( TCPWindow_t *pxWindow, uint32_t ulFirst, uint32_t ulLast );
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210 #endif /* FREERTOS_TCP_WIN_H */
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