diff options
Diffstat (limited to 'FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c')
| -rw-r--r-- | FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c | 1998 |
1 files changed, 1998 insertions, 0 deletions
diff --git a/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c b/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c new file mode 100644 index 000000000..f94b181f7 --- /dev/null +++ b/FreeRTOS-Labs/Source/FreeRTOS-Plus-TCP/FreeRTOS_TCP_WIN.c @@ -0,0 +1,1998 @@ +/*
+ * FreeRTOS+TCP 191100 experimental
+ * Copyright (C) 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://aws.amazon.com/freertos
+ * http://www.FreeRTOS.org
+ */
+
+/*
+ * FreeRTOS_TCP_WIN.c
+ * Module which handles the TCP windowing schemes for FreeRTOS+TCP. Many
+ * functions have two versions - one for FreeRTOS+TCP (full) and one for
+ * FreeRTOS+TCP (lite).
+ *
+ * In this module all ports and IP addresses and sequence numbers are
+ * being stored in host byte-order.
+ */
+
+/* Standard includes. */
+#include <stdint.h>
+
+/* FreeRTOS includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+#include "queue.h"
+#include "semphr.h"
+
+/* FreeRTOS+TCP includes. */
+#include "FreeRTOS_UDP_IP.h"
+#include "FreeRTOS_IP.h"
+#include "FreeRTOS_Sockets.h"
+#include "FreeRTOS_IP_Private.h"
+#include "NetworkBufferManagement.h"
+#include "FreeRTOS_TCP_WIN.h"
+
+/* Constants used for Smoothed Round Trip Time (SRTT). */
+#define winSRTT_INCREMENT_NEW 2
+#define winSRTT_INCREMENT_CURRENT 6
+#define winSRTT_DECREMENT_NEW 1
+#define winSRTT_DECREMENT_CURRENT 7
+#define winSRTT_CAP_mS 50
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ #define xTCPWindowRxNew( pxWindow, ulSequenceNumber, lCount ) xTCPWindowNew( pxWindow, ulSequenceNumber, lCount, pdTRUE )
+
+ #define xTCPWindowTxNew( pxWindow, ulSequenceNumber, lCount ) xTCPWindowNew( pxWindow, ulSequenceNumber, lCount, pdFALSE )
+
+ /* The code to send a single Selective ACK (SACK):
+ * NOP (0x01), NOP (0x01), SACK (0x05), LEN (0x0a),
+ * followed by a lower and a higher sequence number,
+ * where LEN is 2 + 2*4 = 10 bytes. */
+ #if( ipconfigBYTE_ORDER == pdFREERTOS_BIG_ENDIAN )
+ #define OPTION_CODE_SINGLE_SACK ( 0x0101050aUL )
+ #else
+ #define OPTION_CODE_SINGLE_SACK ( 0x0a050101UL )
+ #endif
+
+ /* Normal retransmission:
+ * A packet will be retransmitted after a Retransmit Time-Out (RTO).
+ * Fast retransmission:
+ * When 3 packets with a higher sequence number have been acknowledged
+ * by the peer, it is very unlikely a current packet will ever arrive.
+ * It will be retransmitted far before the RTO.
+ */
+ #define DUPLICATE_ACKS_BEFORE_FAST_RETRANSMIT ( 3u )
+
+ /* If there have been several retransmissions (4), decrease the
+ * size of the transmission window to at most 2 times MSS.
+ */
+ #define MAX_TRANSMIT_COUNT_USING_LARGE_WINDOW ( 4u )
+
+#endif /* configUSE_TCP_WIN */
+/*-----------------------------------------------------------*/
+
+extern void vListInsertGeneric( List_t * const pxList, ListItem_t * const pxNewListItem, MiniListItem_t * const pxWhere );
+
+/*
+ * All TCP sockets share a pool of segment descriptors (TCPSegment_t)
+ * Available descriptors are stored in the 'xSegmentList'
+ * When a socket owns a descriptor, it will either be stored in
+ * 'xTxSegments' or 'xRxSegments'
+ * As soon as a package has been confirmed, the descriptor will be returned
+ * to the segment pool
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static BaseType_t prvCreateSectors( void );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * Find a segment with a given sequence number in the list of received
+ * segments: 'pxWindow->xRxSegments'.
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPWindowRxFind( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * Allocate a new segment
+ * The socket will borrow all segments from a common pool: 'xSegmentList',
+ * which is a list of 'TCPSegment_t'
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPWindowNew( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, int32_t lCount, BaseType_t xIsForRx );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/* When the peer has a close request (FIN flag), the driver will check if
+ * there are missing packets in the Rx-queue
+ * It will accept the closure of the connection if both conditions are true:
+ * - the Rx-queue is empty
+ * - we've ACK'd the highest Rx sequence number seen
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ BaseType_t xTCPWindowRxEmpty( TCPWindow_t *pxWindow );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * Detaches and returns the head of a queue
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPWindowGetHead( List_t *pxList );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * Returns the head of a queue but it won't be detached
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPWindowPeekHead( List_t *pxList );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * Free entry pxSegment because it's not used anymore
+ * The ownership will be passed back to the segment pool
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static void vTCPWindowFree( TCPSegment_t *pxSegment );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * A segment has been received with sequence number 'ulSequenceNumber', where
+ * 'ulCurrentSequenceNumber == ulSequenceNumber', which means that exactly this
+ * segment was expected. xTCPWindowRxConfirm() will check if there is already
+ * another segment with a sequence number between (ulSequenceNumber) and
+ * (ulSequenceNumber+xLength). Normally none will be found, because the next Rx
+ * segment should have a sequence number equal to '(ulSequenceNumber+xLength)'.
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPWindowRxConfirm( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * FreeRTOS+TCP stores data in circular buffers. Calculate the next position to
+ * store.
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static int32_t lTCPIncrementTxPosition( int32_t lPosition, int32_t lMax, int32_t lCount );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * This function will look if there is new transmission data. It will return
+ * true if there is data to be sent.
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * An acknowledge was received. See if some outstanding data may be removed
+ * from the transmission queue(s).
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static uint32_t prvTCPWindowTxCheckAck( TCPWindow_t *pxWindow, uint32_t ulFirst, uint32_t ulLast );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*
+ * A higher Tx block has been acknowledged. Now iterate through the xWaitQueue
+ * to find a possible condition for a FAST retransmission.
+ */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static uint32_t prvTCPWindowFastRetransmit( TCPWindow_t *pxWindow, uint32_t ulFirst );
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/*-----------------------------------------------------------*/
+
+/* TCP segment pool. */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static TCPSegment_t *xTCPSegments = NULL;
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+
+/* List of free TCP segments. */
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static List_t xSegmentList;
+#endif
+
+/* Logging verbosity level. */
+BaseType_t xTCPWindowLoggingLevel = 0;
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+ /* Some 32-bit arithmetic: comparing sequence numbers */
+ static portINLINE BaseType_t xSequenceLessThanOrEqual( uint32_t a, uint32_t b );
+ static portINLINE BaseType_t xSequenceLessThanOrEqual( uint32_t a, uint32_t b )
+ {
+ /* Test if a <= b
+ Return true if the unsigned subtraction of (b-a) doesn't generate an
+ arithmetic overflow. */
+ return ( ( b - a ) & 0x80000000UL ) == 0UL;
+ }
+#endif /* ipconfigUSE_TCP_WIN */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static portINLINE BaseType_t xSequenceLessThan( uint32_t a, uint32_t b );
+ static portINLINE BaseType_t xSequenceLessThan( uint32_t a, uint32_t b )
+ {
+ /* Test if a < b */
+ return ( ( b - a - 1UL ) & 0x80000000UL ) == 0UL;
+ }
+#endif /* ipconfigUSE_TCP_WIN */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static portINLINE BaseType_t xSequenceGreaterThan( uint32_t a, uint32_t b );
+ static portINLINE BaseType_t xSequenceGreaterThan( uint32_t a, uint32_t b )
+ {
+ /* Test if a > b */
+ return ( ( a - b - 1UL ) & 0x80000000UL ) == 0UL;
+ }
+#endif /* ipconfigUSE_TCP_WIN */
+
+/*-----------------------------------------------------------*/
+static portINLINE BaseType_t xSequenceGreaterThanOrEqual( uint32_t a, uint32_t b );
+static portINLINE BaseType_t xSequenceGreaterThanOrEqual( uint32_t a, uint32_t b )
+{
+ /* Test if a >= b */
+ return ( ( a - b ) & 0x80000000UL ) == 0UL;
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+ static portINLINE void vListInsertFifo( List_t * const pxList, ListItem_t * const pxNewListItem );
+ static portINLINE void vListInsertFifo( List_t * const pxList, ListItem_t * const pxNewListItem )
+ {
+ vListInsertGeneric( pxList, pxNewListItem, &pxList->xListEnd );
+ }
+#endif
+/*-----------------------------------------------------------*/
+
+static portINLINE void vTCPTimerSet( TCPTimer_t *pxTimer );
+static portINLINE void vTCPTimerSet( TCPTimer_t *pxTimer )
+{
+ pxTimer->ulBorn = xTaskGetTickCount ( );
+}
+/*-----------------------------------------------------------*/
+
+static portINLINE uint32_t ulTimerGetAge( TCPTimer_t *pxTimer );
+static portINLINE uint32_t ulTimerGetAge( TCPTimer_t *pxTimer )
+{
+ return ( ( xTaskGetTickCount() - pxTimer->ulBorn ) * portTICK_PERIOD_MS );
+}
+/*-----------------------------------------------------------*/
+
+/* _HT_ GCC (using the settings that I'm using) checks for every public function if it is
+preceded by a prototype. Later this prototype will be located in list.h? */
+
+extern void vListInsertGeneric( List_t * const pxList, ListItem_t * const pxNewListItem, MiniListItem_t * const pxWhere );
+
+void vListInsertGeneric( List_t * const pxList, ListItem_t * const pxNewListItem, MiniListItem_t * const pxWhere )
+{
+ /* Insert a new list item into pxList, it does not sort the list,
+ but it puts the item just before xListEnd, so it will be the last item
+ returned by listGET_HEAD_ENTRY() */
+ pxNewListItem->pxNext = (struct xLIST_ITEM * configLIST_VOLATILE)pxWhere;
+ pxNewListItem->pxPrevious = pxWhere->pxPrevious;
+ pxWhere->pxPrevious->pxNext = pxNewListItem;
+ pxWhere->pxPrevious = pxNewListItem;
+
+ /* Remember which list the item is in. */
+ listLIST_ITEM_CONTAINER( pxNewListItem ) = ( void * ) pxList;
+
+ ( pxList->uxNumberOfItems )++;
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static BaseType_t prvCreateSectors( void )
+ {
+ BaseType_t xIndex, xReturn;
+
+ /* Allocate space for 'xTCPSegments' and store them in 'xSegmentList'. */
+
+ vListInitialise( &xSegmentList );
+ xTCPSegments = ( TCPSegment_t * ) pvPortMallocLarge( ipconfigTCP_WIN_SEG_COUNT * sizeof( xTCPSegments[ 0 ] ) );
+
+ if( xTCPSegments == NULL )
+ {
+ FreeRTOS_debug_printf( ( "prvCreateSectors: malloc %lu failed\n",
+ ipconfigTCP_WIN_SEG_COUNT * sizeof( xTCPSegments[ 0 ] ) ) );
+
+ xReturn = pdFAIL;
+ }
+ else
+ {
+ /* Clear the allocated space. */
+ memset( xTCPSegments, '\0', ipconfigTCP_WIN_SEG_COUNT * sizeof( xTCPSegments[ 0 ] ) );
+
+ for( xIndex = 0; xIndex < ipconfigTCP_WIN_SEG_COUNT; xIndex++ )
+ {
+ /* Could call vListInitialiseItem here but all data has been
+ nulled already. Set the owner to a segment descriptor. */
+ listSET_LIST_ITEM_OWNER( &( xTCPSegments[ xIndex ].xListItem ), ( void* ) &( xTCPSegments[ xIndex ] ) );
+ listSET_LIST_ITEM_OWNER( &( xTCPSegments[ xIndex ].xQueueItem ), ( void* ) &( xTCPSegments[ xIndex ] ) );
+
+ /* And add it to the pool of available segments */
+ vListInsertFifo( &xSegmentList, &( xTCPSegments[xIndex].xListItem ) );
+ }
+
+ xReturn = pdPASS;
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static TCPSegment_t *xTCPWindowRxFind( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber )
+ {
+ const ListItem_t *pxIterator;
+ const MiniListItem_t* pxEnd;
+ TCPSegment_t *pxSegment, *pxReturn = NULL;
+
+ /* Find a segment with a given sequence number in the list of received
+ segments. */
+
+ pxEnd = ( const MiniListItem_t* )listGET_END_MARKER( &pxWindow->xRxSegments );
+
+ for( pxIterator = ( const ListItem_t * ) listGET_NEXT( pxEnd );
+ pxIterator != ( const ListItem_t * ) pxEnd;
+ pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator ) )
+ {
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+
+ if( pxSegment->ulSequenceNumber == ulSequenceNumber )
+ {
+ pxReturn = pxSegment;
+ break;
+ }
+ }
+
+ return pxReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static TCPSegment_t *xTCPWindowNew( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, int32_t lCount, BaseType_t xIsForRx )
+ {
+ TCPSegment_t *pxSegment;
+ ListItem_t * pxItem;
+
+ /* Allocate a new segment. The socket will borrow all segments from a
+ common pool: 'xSegmentList', which is a list of 'TCPSegment_t' */
+ if( listLIST_IS_EMPTY( &xSegmentList ) != pdFALSE )
+ {
+ /* If the TCP-stack runs out of segments, you might consider
+ increasing 'ipconfigTCP_WIN_SEG_COUNT'. */
+ FreeRTOS_debug_printf( ( "xTCPWindow%cxNew: Error: all segments occupied\n", xIsForRx ? 'R' : 'T' ) );
+ pxSegment = NULL;
+ }
+ else
+ {
+ /* Pop the item at the head of the list. Semaphore protection is
+ not required as only the IP task will call these functions. */
+ pxItem = ( ListItem_t * ) listGET_HEAD_ENTRY( &xSegmentList );
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxItem );
+
+ configASSERT( pxItem != NULL );
+ configASSERT( pxSegment != NULL );
+
+ /* Remove the item from xSegmentList. */
+ uxListRemove( pxItem );
+
+ /* Add it to either the connections' Rx or Tx queue. */
+ vListInsertFifo( xIsForRx ? &pxWindow->xRxSegments : &pxWindow->xTxSegments, pxItem );
+
+ /* And set the segment's timer to zero */
+ vTCPTimerSet( &pxSegment->xTransmitTimer );
+
+ pxSegment->u.ulFlags = 0;
+ pxSegment->u.bits.bIsForRx = ( xIsForRx != 0 );
+ pxSegment->lMaxLength = lCount;
+ pxSegment->lDataLength = lCount;
+ pxSegment->ulSequenceNumber = ulSequenceNumber;
+ #if( ipconfigHAS_DEBUG_PRINTF != 0 )
+ {
+ static UBaseType_t xLowestLength = ipconfigTCP_WIN_SEG_COUNT;
+ UBaseType_t xLength = listCURRENT_LIST_LENGTH( &xSegmentList );
+
+ if( xLowestLength > xLength )
+ {
+ xLowestLength = xLength;
+ }
+ }
+ #endif /* ipconfigHAS_DEBUG_PRINTF */
+ }
+
+ return pxSegment;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ BaseType_t xTCPWindowRxEmpty( TCPWindow_t *pxWindow )
+ {
+ BaseType_t xReturn;
+
+ /* When the peer has a close request (FIN flag), the driver will check
+ if there are missing packets in the Rx-queue. It will accept the
+ closure of the connection if both conditions are true:
+ - the Rx-queue is empty
+ - the highest Rx sequence number has been ACK'ed */
+ if( listLIST_IS_EMPTY( ( &pxWindow->xRxSegments ) ) == pdFALSE )
+ {
+ /* Rx data has been stored while earlier packets were missing. */
+ xReturn = pdFALSE;
+ }
+ else if( xSequenceGreaterThanOrEqual( pxWindow->rx.ulCurrentSequenceNumber, pxWindow->rx.ulHighestSequenceNumber ) != pdFALSE )
+ {
+ /* No Rx packets are being stored and the highest sequence number
+ that has been received has been ACKed. */
+ xReturn = pdTRUE;
+ }
+ else
+ {
+ FreeRTOS_debug_printf( ( "xTCPWindowRxEmpty: cur %lu highest %lu (empty)\n",
+ ( pxWindow->rx.ulCurrentSequenceNumber - pxWindow->rx.ulFirstSequenceNumber ),
+ ( pxWindow->rx.ulHighestSequenceNumber - pxWindow->rx.ulFirstSequenceNumber ) ) );
+ xReturn = pdFALSE;
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static TCPSegment_t *xTCPWindowGetHead( List_t *pxList )
+ {
+ TCPSegment_t *pxSegment;
+ ListItem_t * pxItem;
+
+ /* Detaches and returns the head of a queue. */
+ if( listLIST_IS_EMPTY( pxList ) != pdFALSE )
+ {
+ pxSegment = NULL;
+ }
+ else
+ {
+ pxItem = ( ListItem_t * ) listGET_HEAD_ENTRY( pxList );
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxItem );
+
+ uxListRemove( pxItem );
+ }
+
+ return pxSegment;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static TCPSegment_t *xTCPWindowPeekHead( List_t *pxList )
+ {
+ ListItem_t *pxItem;
+ TCPSegment_t *pxReturn;
+
+ /* Returns the head of a queue but it won't be detached. */
+ if( listLIST_IS_EMPTY( pxList ) != pdFALSE )
+ {
+ pxReturn = NULL;
+ }
+ else
+ {
+ pxItem = ( ListItem_t * ) listGET_HEAD_ENTRY( pxList );
+ pxReturn = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxItem );
+ }
+
+ return pxReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static void vTCPWindowFree( TCPSegment_t *pxSegment )
+ {
+ /* Free entry pxSegment because it's not used any more. The ownership
+ will be passed back to the segment pool.
+
+ Unlink it from one of the queues, if any. */
+ if( listLIST_ITEM_CONTAINER( &( pxSegment->xQueueItem ) ) != NULL )
+ {
+ uxListRemove( &( pxSegment->xQueueItem ) );
+ }
+
+ pxSegment->ulSequenceNumber = 0u;
+ pxSegment->lDataLength = 0l;
+ pxSegment->u.ulFlags = 0u;
+
+ /* Take it out of xRxSegments/xTxSegments */
+ if( listLIST_ITEM_CONTAINER( &( pxSegment->xListItem ) ) != NULL )
+ {
+ uxListRemove( &( pxSegment->xListItem ) );
+ }
+
+ /* Return it to xSegmentList */
+ vListInsertFifo( &xSegmentList, &( pxSegment->xListItem ) );
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ void vTCPWindowDestroy( TCPWindow_t *pxWindow )
+ {
+ List_t * pxSegments;
+ BaseType_t xRound;
+ TCPSegment_t *pxSegment;
+
+ /* Destroy a window. A TCP window doesn't serve any more. Return all
+ owned segments to the pool. In order to save code, it will make 2 rounds,
+ one to remove the segments from xRxSegments, and a second round to clear
+ xTxSegments*/
+ for( xRound = 0; xRound < 2; xRound++ )
+ {
+ if( xRound != 0 )
+ {
+ pxSegments = &( pxWindow->xRxSegments );
+ }
+ else
+ {
+ pxSegments = &( pxWindow->xTxSegments );
+ }
+
+ if( listLIST_IS_INITIALISED( pxSegments ) != pdFALSE )
+ {
+ while( listCURRENT_LIST_LENGTH( pxSegments ) > 0U )
+ {
+ pxSegment = ( TCPSegment_t * ) listGET_OWNER_OF_HEAD_ENTRY( pxSegments );
+ vTCPWindowFree( pxSegment );
+ }
+ }
+ }
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+void vTCPWindowCreate( TCPWindow_t *pxWindow, uint32_t ulRxWindowLength,
+ uint32_t ulTxWindowLength, uint32_t ulAckNumber, uint32_t ulSequenceNumber, uint32_t ulMSS )
+{
+ /* Create and initialize a window. */
+
+ #if( ipconfigUSE_TCP_WIN == 1 )
+ {
+ if( xTCPSegments == NULL )
+ {
+ prvCreateSectors();
+ }
+
+ vListInitialise( &pxWindow->xTxSegments );
+ vListInitialise( &pxWindow->xRxSegments );
+
+ vListInitialise( &pxWindow->xPriorityQueue ); /* Priority queue: segments which must be sent immediately */
+ vListInitialise( &pxWindow->xTxQueue ); /* Transmit queue: segments queued for transmission */
+ vListInitialise( &pxWindow->xWaitQueue ); /* Waiting queue: outstanding segments */
+ }
+ #endif /* ipconfigUSE_TCP_WIN == 1 */
+
+ if( xTCPWindowLoggingLevel != 0 )
+ {
+ FreeRTOS_debug_printf( ( "vTCPWindowCreate: for WinLen = Rx/Tx: %lu/%lu\n",
+ ulRxWindowLength, ulTxWindowLength ) );
+ }
+
+ pxWindow->xSize.ulRxWindowLength = ulRxWindowLength;
+ pxWindow->xSize.ulTxWindowLength = ulTxWindowLength;
+
+ vTCPWindowInit( pxWindow, ulAckNumber, ulSequenceNumber, ulMSS );
+}
+/*-----------------------------------------------------------*/
+
+void vTCPWindowInit( TCPWindow_t *pxWindow, uint32_t ulAckNumber, uint32_t ulSequenceNumber, uint32_t ulMSS )
+{
+const int32_t l500ms = 500;
+
+ pxWindow->u.ulFlags = 0ul;
+ pxWindow->u.bits.bHasInit = pdTRUE_UNSIGNED;
+
+ if( ulMSS != 0ul )
+ {
+ if( pxWindow->usMSSInit != 0u )
+ {
+ pxWindow->usMSSInit = ( uint16_t ) ulMSS;
+ }
+
+ if( ( ulMSS < ( uint32_t ) pxWindow->usMSS ) || ( pxWindow->usMSS == 0u ) )
+ {
+ pxWindow->xSize.ulRxWindowLength = ( pxWindow->xSize.ulRxWindowLength / ulMSS ) * ulMSS;
+ pxWindow->usMSS = ( uint16_t ) ulMSS;
+ }
+ }
+
+ #if( ipconfigUSE_TCP_WIN == 0 )
+ {
+ pxWindow->xTxSegment.lMaxLength = ( int32_t ) pxWindow->usMSS;
+ }
+ #endif /* ipconfigUSE_TCP_WIN == 1 */
+
+ /*Start with a timeout of 2 * 500 ms (1 sec). */
+ pxWindow->lSRTT = l500ms;
+
+ /* Just for logging, to print relative sequence numbers. */
+ pxWindow->rx.ulFirstSequenceNumber = ulAckNumber;
+
+ /* The segment asked for in the next transmission. */
+ pxWindow->rx.ulCurrentSequenceNumber = ulAckNumber;
+
+ /* The right-hand side of the receive window. */
+ pxWindow->rx.ulHighestSequenceNumber = ulAckNumber;
+
+ pxWindow->tx.ulFirstSequenceNumber = ulSequenceNumber;
+
+ /* The segment asked for in next transmission. */
+ pxWindow->tx.ulCurrentSequenceNumber = ulSequenceNumber;
+
+ /* The sequence number given to the next outgoing byte to be added is
+ maintained by lTCPWindowTxAdd(). */
+ pxWindow->ulNextTxSequenceNumber = ulSequenceNumber;
+
+ /* The right-hand side of the transmit window. */
+ pxWindow->tx.ulHighestSequenceNumber = ulSequenceNumber;
+ pxWindow->ulOurSequenceNumber = ulSequenceNumber;
+}
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ void vTCPSegmentCleanup( void )
+ {
+ /* Free and clear the TCP segments pointer. This function should only be called
+ * once FreeRTOS+TCP will no longer be used. No thread-safety is provided for this
+ * function. */
+ if( xTCPSegments != NULL )
+ {
+ vPortFreeLarge( xTCPSegments );
+ xTCPSegments = NULL;
+ }
+ }
+
+#endif /* ipconfgiUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+/*=============================================================================
+ *
+ * ###### # #
+ * # # # #
+ * # # # #
+ * # # ####
+ * ###### ##
+ * # ## ####
+ * # # # #
+ * # # # #
+ * ### ## # #
+ * Rx functions
+ *
+ *=============================================================================*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static TCPSegment_t *xTCPWindowRxConfirm( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength )
+ {
+ TCPSegment_t *pxBest = NULL;
+ const ListItem_t *pxIterator;
+ uint32_t ulNextSequenceNumber = ulSequenceNumber + ulLength;
+ const MiniListItem_t* pxEnd = ( const MiniListItem_t* ) listGET_END_MARKER( &pxWindow->xRxSegments );
+ TCPSegment_t *pxSegment;
+
+ /* A segment has been received with sequence number 'ulSequenceNumber',
+ where 'ulCurrentSequenceNumber == ulSequenceNumber', which means that
+ exactly this segment was expected. xTCPWindowRxConfirm() will check if
+ there is already another segment with a sequence number between (ulSequenceNumber)
+ and (ulSequenceNumber+ulLength). Normally none will be found, because
+ the next RX segment should have a sequence number equal to
+ '(ulSequenceNumber+ulLength)'. */
+
+ /* Iterate through all RX segments that are stored: */
+ for( pxIterator = ( const ListItem_t * ) listGET_NEXT( pxEnd );
+ pxIterator != ( const ListItem_t * ) pxEnd;
+ pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator ) )
+ {
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+ /* And see if there is a segment for which:
+ 'ulSequenceNumber' <= 'pxSegment->ulSequenceNumber' < 'ulNextSequenceNumber'
+ If there are more matching segments, the one with the lowest sequence number
+ shall be taken */
+ if( ( xSequenceGreaterThanOrEqual( pxSegment->ulSequenceNumber, ulSequenceNumber ) != 0 ) &&
+ ( xSequenceLessThan( pxSegment->ulSequenceNumber, ulNextSequenceNumber ) != 0 ) )
+ {
+ if( ( pxBest == NULL ) || ( xSequenceLessThan( pxSegment->ulSequenceNumber, pxBest->ulSequenceNumber ) != 0 ) )
+ {
+ pxBest = pxSegment;
+ }
+ }
+ }
+
+ if( ( pxBest != NULL ) &&
+ ( ( pxBest->ulSequenceNumber != ulSequenceNumber ) || ( pxBest->lDataLength != ( int32_t ) ulLength ) ) )
+ {
+ FreeRTOS_flush_logging();
+ FreeRTOS_debug_printf( ( "xTCPWindowRxConfirm[%u]: search %lu (+%ld=%lu) found %lu (+%ld=%lu)\n",
+ pxWindow->usPeerPortNumber,
+ ulSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ ulLength,
+ ulSequenceNumber + ulLength - pxWindow->rx.ulFirstSequenceNumber,
+ pxBest->ulSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ pxBest->lDataLength,
+ pxBest->ulSequenceNumber + ( ( uint32_t ) pxBest->lDataLength ) - pxWindow->rx.ulFirstSequenceNumber ) );
+ }
+
+ return pxBest;
+ }
+
+#endif /* ipconfgiUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ int32_t lTCPWindowRxCheck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength, uint32_t ulSpace )
+ {
+ uint32_t ulCurrentSequenceNumber, ulLast, ulSavedSequenceNumber;
+ int32_t lReturn, lDistance;
+ TCPSegment_t *pxFound;
+
+ /* If lTCPWindowRxCheck( ) returns == 0, the packet will be passed
+ directly to user (segment is expected). If it returns a positive
+ number, an earlier packet is missing, but this packet may be stored.
+ If negative, the packet has already been stored, or it is out-of-order,
+ or there is not enough space.
+
+ As a side-effect, pxWindow->ulUserDataLength will get set to non-zero,
+ if more Rx data may be passed to the user after this packet. */
+
+ ulCurrentSequenceNumber = pxWindow->rx.ulCurrentSequenceNumber;
+
+ /* For Selective Ack (SACK), used when out-of-sequence data come in. */
+ pxWindow->ucOptionLength = 0u;
+
+ /* Non-zero if TCP-windows contains data which must be popped. */
+ pxWindow->ulUserDataLength = 0ul;
+
+ if( ulCurrentSequenceNumber == ulSequenceNumber )
+ {
+ /* This is the packet with the lowest sequence number we're waiting
+ for. It can be passed directly to the rx stream. */
+ if( ulLength > ulSpace )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowRxCheck: Refuse %lu bytes, due to lack of space (%lu)\n", ulLength, ulSpace ) );
+ lReturn = -1;
+ }
+ else
+ {
+ ulCurrentSequenceNumber += ulLength;
+
+ if( listCURRENT_LIST_LENGTH( &( pxWindow->xRxSegments ) ) != 0 )
+ {
+ ulSavedSequenceNumber = ulCurrentSequenceNumber;
+
+ /* Clean up all sequence received between ulSequenceNumber and ulSequenceNumber + ulLength since they are duplicated.
+ If the server is forced to retransmit packets several time in a row it might send a batch of concatenated packet for speed.
+ So we cannot rely on the packets between ulSequenceNumber and ulSequenceNumber + ulLength to be sequential and it is better to just
+ clean them out. */
+ do
+ {
+ pxFound = xTCPWindowRxConfirm( pxWindow, ulSequenceNumber, ulLength );
+
+ if ( pxFound != NULL )
+ {
+ /* Remove it because it will be passed to user directly. */
+ vTCPWindowFree( pxFound );
+ }
+ } while ( pxFound );
+
+ /* Check for following segments that are already in the
+ queue and increment ulCurrentSequenceNumber. */
+ while( ( pxFound = xTCPWindowRxFind( pxWindow, ulCurrentSequenceNumber ) ) != NULL )
+ {
+ ulCurrentSequenceNumber += ( uint32_t ) pxFound->lDataLength;
+
+ /* As all packet below this one have been passed to the
+ user it can be discarded. */
+ vTCPWindowFree( pxFound );
+ }
+
+ if( ulSavedSequenceNumber != ulCurrentSequenceNumber )
+ {
+ /* After the current data-package, there is more data
+ to be popped. */
+ pxWindow->ulUserDataLength = ulCurrentSequenceNumber - ulSavedSequenceNumber;
+
+ if( xTCPWindowLoggingLevel >= 1 )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowRxCheck[%d,%d]: retran %lu (Found %lu bytes at %lu cnt %ld)\n",
+ pxWindow->usPeerPortNumber, pxWindow->usOurPortNumber,
+ ulSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ pxWindow->ulUserDataLength,
+ ulSavedSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ listCURRENT_LIST_LENGTH( &pxWindow->xRxSegments ) ) );
+ }
+ }
+ }
+
+ pxWindow->rx.ulCurrentSequenceNumber = ulCurrentSequenceNumber;
+
+ /* Packet was expected, may be passed directly to the socket
+ buffer or application. Store the packet at offset 0. */
+ lReturn = 0;
+ }
+ }
+ else if( ulCurrentSequenceNumber == ( ulSequenceNumber + 1UL ) )
+ {
+ /* Looks like a TCP keep-alive message. Do not accept/store Rx data
+ ulUserDataLength = 0. Not packet out-of-sync. Just reply to it. */
+ lReturn = -1;
+ }
+ else
+ {
+ /* The packet is not the one expected. See if it falls within the Rx
+ window so it can be stored. */
+
+ /* An "out-of-sequence" segment was received, must have missed one.
+ Prepare a SACK (Selective ACK). */
+ ulLast = ulSequenceNumber + ulLength;
+ lDistance = ( int32_t ) ( ulLast - ulCurrentSequenceNumber );
+
+ if( lDistance <= 0 )
+ {
+ /* An earlier has been received, must be a retransmission of a
+ packet that has been accepted already. No need to send out a
+ Selective ACK (SACK). */
+ lReturn = -1;
+ }
+ else if( lDistance > ( int32_t ) ulSpace )
+ {
+ /* The new segment is ahead of rx.ulCurrentSequenceNumber. The
+ sequence number of this packet is too far ahead, ignore it. */
+ FreeRTOS_debug_printf( ( "lTCPWindowRxCheck: Refuse %lu+%lu bytes, due to lack of space (%lu)\n", lDistance, ulLength, ulSpace ) );
+ lReturn = -1;
+ }
+ else
+ {
+ /* See if there is more data in a contiguous block to make the
+ SACK describe a longer range of data. */
+
+ /* TODO: SACK's may also be delayed for a short period
+ * This is useful because subsequent packets will be SACK'd with
+ * single one message
+ */
+ while( ( pxFound = xTCPWindowRxFind( pxWindow, ulLast ) ) != NULL )
+ {
+ ulLast += ( uint32_t ) pxFound->lDataLength;
+ }
+
+ if( xTCPWindowLoggingLevel >= 1 )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowRxCheck[%d,%d]: seqnr %lu exp %lu (dist %ld) SACK to %lu\n",
+ pxWindow->usPeerPortNumber, pxWindow->usOurPortNumber,
+ ulSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ ulCurrentSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ ( BaseType_t ) ( ulSequenceNumber - ulCurrentSequenceNumber ), /* want this signed */
+ ulLast - pxWindow->rx.ulFirstSequenceNumber ) );
+ }
+
+ /* Now prepare the SACK message.
+ Code OPTION_CODE_SINGLE_SACK already in network byte order. */
+ pxWindow->ulOptionsData[0] = OPTION_CODE_SINGLE_SACK;
+
+ /* First sequence number that we received. */
+ pxWindow->ulOptionsData[1] = FreeRTOS_htonl( ulSequenceNumber );
+
+ /* Last + 1 */
+ pxWindow->ulOptionsData[2] = FreeRTOS_htonl( ulLast );
+
+ /* Which make 12 (3*4) option bytes. */
+ pxWindow->ucOptionLength = 3 * sizeof( pxWindow->ulOptionsData[ 0 ] );
+
+ pxFound = xTCPWindowRxFind( pxWindow, ulSequenceNumber );
+
+ if( pxFound != NULL )
+ {
+ /* This out-of-sequence packet has been received for a
+ second time. It is already stored but do send a SACK
+ again. */
+ lReturn = -1;
+ }
+ else
+ {
+ pxFound = xTCPWindowRxNew( pxWindow, ulSequenceNumber, ( int32_t ) ulLength );
+
+ if( pxFound == NULL )
+ {
+ /* Can not send a SACK, because the segment cannot be
+ stored. */
+ pxWindow->ucOptionLength = 0u;
+
+ /* Needs to be stored but there is no segment
+ available. */
+ lReturn = -1;
+ }
+ else
+ {
+ if( xTCPWindowLoggingLevel != 0 )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowRxCheck[%u,%u]: seqnr %lu (cnt %lu)\n",
+ pxWindow->usPeerPortNumber, pxWindow->usOurPortNumber, ulSequenceNumber - pxWindow->rx.ulFirstSequenceNumber,
+ listCURRENT_LIST_LENGTH( &pxWindow->xRxSegments ) ) );
+ FreeRTOS_flush_logging( );
+ }
+
+ /* Return a positive value. The packet may be accepted
+ and stored but an earlier packet is still missing. */
+ lReturn = ( int32_t ) ( ulSequenceNumber - ulCurrentSequenceNumber );
+ }
+ }
+ }
+ }
+
+ return lReturn;
+ }
+
+#endif /* ipconfgiUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+/*=============================================================================
+ *
+ * ######### # #
+ * # # # # #
+ * # # #
+ * # ####
+ * # ##
+ * # ####
+ * # # #
+ * # # #
+ * ##### # #
+ *
+ * Tx functions
+ *
+ *=============================================================================*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static int32_t lTCPIncrementTxPosition( int32_t lPosition, int32_t lMax, int32_t lCount )
+ {
+ /* +TCP stores data in circular buffers. Calculate the next position to
+ store. */
+ lPosition += lCount;
+ if( lPosition >= lMax )
+ {
+ lPosition -= lMax;
+ }
+
+ return lPosition;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ int32_t lTCPWindowTxAdd( TCPWindow_t *pxWindow, uint32_t ulLength, int32_t lPosition, int32_t lMax )
+ {
+ int32_t lBytesLeft = ( int32_t ) ulLength, lToWrite;
+ int32_t lDone = 0;
+ TCPSegment_t *pxSegment = pxWindow->pxHeadSegment;
+
+ /* Puts a message in the Tx-window (after buffer size has been
+ verified). */
+ if( pxSegment != NULL )
+ {
+ if( pxSegment->lDataLength < pxSegment->lMaxLength )
+ {
+ if( ( pxSegment->u.bits.bOutstanding == pdFALSE_UNSIGNED ) && ( pxSegment->lDataLength != 0 ) )
+ {
+ /* Adding data to a segment that was already in the TX queue. It
+ will be filled-up to a maximum of MSS (maximum segment size). */
+ lToWrite = FreeRTOS_min_int32( lBytesLeft, pxSegment->lMaxLength - pxSegment->lDataLength );
+
+ pxSegment->lDataLength += lToWrite;
+
+ if( pxSegment->lDataLength >= pxSegment->lMaxLength )
+ {
+ /* This segment is full, don't add more bytes. */
+ pxWindow->pxHeadSegment = NULL;
+ }
+
+ lBytesLeft -= lToWrite;
+
+ /* ulNextTxSequenceNumber is the sequence number of the next byte to
+ be stored for transmission. */
+ pxWindow->ulNextTxSequenceNumber += ( uint32_t ) lToWrite;
+
+ /* Increased the return value. */
+ lDone += lToWrite;
+
+ /* Some detailed logging, for those who're interested. */
+ if( ( xTCPWindowLoggingLevel >= 2 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != 0 ) )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowTxAdd: Add %4lu bytes for seqNr %lu len %4lu (nxt %lu) pos %lu\n",
+ ulLength,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->lDataLength,
+ pxWindow->ulNextTxSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->lStreamPos ) );
+ FreeRTOS_flush_logging( );
+ }
+
+ /* Calculate the next position in the circular data buffer, knowing
+ its maximum length 'lMax'. */
+ lPosition = lTCPIncrementTxPosition( lPosition, lMax, lToWrite );
+ }
+ }
+ }
+
+ while( lBytesLeft > 0 )
+ {
+ /* The current transmission segment is full, create new segments as
+ needed. */
+ pxSegment = xTCPWindowTxNew( pxWindow, pxWindow->ulNextTxSequenceNumber, pxWindow->usMSS );
+
+ if( pxSegment != NULL )
+ {
+ /* Store as many as needed, but no more than the maximum
+ (MSS). */
+ lToWrite = FreeRTOS_min_int32( lBytesLeft, pxSegment->lMaxLength );
+
+ pxSegment->lDataLength = lToWrite;
+ pxSegment->lStreamPos = lPosition;
+ lBytesLeft -= lToWrite;
+ lPosition = lTCPIncrementTxPosition( lPosition, lMax, lToWrite );
+ pxWindow->ulNextTxSequenceNumber += ( uint32_t ) lToWrite;
+ lDone += lToWrite;
+
+ /* Link this segment in the Tx-Queue. */
+ vListInsertFifo( &( pxWindow->xTxQueue ), &( pxSegment->xQueueItem ) );
+
+ /* Let 'pxHeadSegment' point to this segment if there is still
+ space. */
+ if( pxSegment->lDataLength < pxSegment->lMaxLength )
+ {
+ pxWindow->pxHeadSegment = pxSegment;
+ }
+ else
+ {
+ pxWindow->pxHeadSegment = NULL;
+ }
+
+ if( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != 0 )
+ {
+ if( ( xTCPWindowLoggingLevel >= 3 ) ||
+ ( ( xTCPWindowLoggingLevel >= 2 ) && ( pxWindow->pxHeadSegment != NULL ) ) )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowTxAdd: New %4ld bytes for seqNr %lu len %4lu (nxt %lu) pos %lu\n",
+ ulLength,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->lDataLength,
+ pxWindow->ulNextTxSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->lStreamPos ) );
+ FreeRTOS_flush_logging( );
+ }
+ }
+ }
+ else
+ {
+ /* A sever situation: running out of segments for transmission.
+ No more data can be sent at the moment. */
+ if( lDone != 0 )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowTxAdd: Sorry all buffers full (cancel %ld bytes)\n", lBytesLeft ) );
+ }
+ break;
+ }
+ }
+
+ return lDone;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ BaseType_t xTCPWindowTxDone( TCPWindow_t *pxWindow )
+ {
+ return listLIST_IS_EMPTY( ( &pxWindow->xTxSegments) );
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize )
+ {
+ uint32_t ulTxOutstanding;
+ BaseType_t xHasSpace;
+ TCPSegment_t *pxSegment;
+
+ /* This function will look if there is new transmission data. It will
+ return true if there is data to be sent. */
+
+ pxSegment = xTCPWindowPeekHead( &( pxWindow->xTxQueue ) );
+
+ if( pxSegment == NULL )
+ {
+ xHasSpace = pdFALSE;
+ }
+ else
+ {
+ /* How much data is outstanding, i.e. how much data has been sent
+ but not yet acknowledged ? */
+ if( pxWindow->tx.ulHighestSequenceNumber >= pxWindow->tx.ulCurrentSequenceNumber )
+ {
+ ulTxOutstanding = pxWindow->tx.ulHighestSequenceNumber - pxWindow->tx.ulCurrentSequenceNumber;
+ }
+ else
+ {
+ ulTxOutstanding = 0UL;
+ }
+
+ /* Subtract this from the peer's space. */
+ ulWindowSize -= FreeRTOS_min_uint32( ulWindowSize, ulTxOutstanding );
+
+ /* See if the next segment may be sent. */
+ if( ulWindowSize >= ( uint32_t ) pxSegment->lDataLength )
+ {
+ xHasSpace = pdTRUE;
+ }
+ else
+ {
+ xHasSpace = pdFALSE;
+ }
+
+ /* If 'xHasSpace', it looks like the peer has at least space for 1
+ more new segment of size MSS. xSize.ulTxWindowLength is the self-imposed
+ limitation of the transmission window (in case of many resends it
+ may be decreased). */
+ if( ( ulTxOutstanding != 0UL ) && ( pxWindow->xSize.ulTxWindowLength < ulTxOutstanding + ( ( uint32_t ) pxSegment->lDataLength ) ) )
+ {
+ xHasSpace = pdFALSE;
+ }
+ }
+
+ return xHasSpace;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ BaseType_t xTCPWindowTxHasData( TCPWindow_t *pxWindow, uint32_t ulWindowSize, TickType_t *pulDelay )
+ {
+ TCPSegment_t *pxSegment;
+ BaseType_t xReturn;
+ TickType_t ulAge, ulMaxAge;
+
+ *pulDelay = 0u;
+
+ if( listLIST_IS_EMPTY( &pxWindow->xPriorityQueue ) == pdFALSE )
+ {
+ /* No need to look at retransmissions or new transmission as long as
+ there are priority segments. *pulDelay equals zero, meaning it must
+ be sent out immediately. */
+ xReturn = pdTRUE;
+ }
+ else
+ {
+ pxSegment = xTCPWindowPeekHead( &( pxWindow->xWaitQueue ) );
+
+ if( pxSegment != NULL )
+ {
+ /* There is an outstanding segment, see if it is time to resend
+ it. */
+ ulAge = ulTimerGetAge( &pxSegment->xTransmitTimer );
+
+ /* After a packet has been sent for the first time, it will wait
+ '1 * lSRTT' ms for an ACK. A second time it will wait '2 * lSRTT' ms,
+ each time doubling the time-out */
+ ulMaxAge = ( 1u << pxSegment->u.bits.ucTransmitCount ) * ( ( uint32_t ) pxWindow->lSRTT );
+
+ if( ulMaxAge > ulAge )
+ {
+ /* A segment must be sent after this amount of msecs */
+ *pulDelay = ulMaxAge - ulAge;
+ }
+
+ xReturn = pdTRUE;
+ }
+ else
+ {
+ /* No priority segment, no outstanding data, see if there is new
+ transmission data. */
+ pxSegment = xTCPWindowPeekHead( &pxWindow->xTxQueue );
+
+ /* See if it fits in the peer's reception window. */
+ if( pxSegment == NULL )
+ {
+ xReturn = pdFALSE;
+ }
+ else if( prvTCPWindowTxHasSpace( pxWindow, ulWindowSize ) == pdFALSE )
+ {
+ /* Too many outstanding messages. */
+ xReturn = pdFALSE;
+ }
+ else if( ( pxWindow->u.bits.bSendFullSize != pdFALSE_UNSIGNED ) && ( pxSegment->lDataLength < pxSegment->lMaxLength ) )
+ {
+ /* 'bSendFullSize' is a special optimisation. If true, the
+ driver will only sent completely filled packets (of MSS
+ bytes). */
+ xReturn = pdFALSE;
+ }
+ else
+ {
+ xReturn = pdTRUE;
+ }
+ }
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ uint32_t ulTCPWindowTxGet( TCPWindow_t *pxWindow, uint32_t ulWindowSize, int32_t *plPosition )
+ {
+ TCPSegment_t *pxSegment;
+ uint32_t ulMaxTime;
+ uint32_t ulReturn = ~0UL;
+
+
+ /* Fetches data to be sent-out now.
+
+ Priority messages: segments with a resend need no check current sliding
+ window size. */
+ pxSegment = xTCPWindowGetHead( &( pxWindow->xPriorityQueue ) );
+ pxWindow->ulOurSequenceNumber = pxWindow->tx.ulHighestSequenceNumber;
+
+ if( pxSegment == NULL )
+ {
+ /* Waiting messages: outstanding messages with a running timer
+ neither check peer's reception window size because these packets
+ have been sent earlier. */
+ pxSegment = xTCPWindowPeekHead( &( pxWindow->xWaitQueue ) );
+
+ if( pxSegment != NULL )
+ {
+ /* Do check the timing. */
+ ulMaxTime = ( 1u << pxSegment->u.bits.ucTransmitCount ) * ( ( uint32_t ) pxWindow->lSRTT );
+
+ if( ulTimerGetAge( &pxSegment->xTransmitTimer ) > ulMaxTime )
+ {
+ /* A normal (non-fast) retransmission. Move it from the
+ head of the waiting queue. */
+ pxSegment = xTCPWindowGetHead( &( pxWindow->xWaitQueue ) );
+ pxSegment->u.bits.ucDupAckCount = pdFALSE_UNSIGNED;
+
+ /* Some detailed logging. */
+ if( ( xTCPWindowLoggingLevel != 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != 0 ) )
+ {
+ FreeRTOS_debug_printf( ( "ulTCPWindowTxGet[%u,%u]: WaitQueue %ld bytes for sequence number %lu (%lX)\n",
+ pxWindow->usPeerPortNumber,
+ pxWindow->usOurPortNumber,
+ pxSegment->lDataLength,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->ulSequenceNumber ) );
+ FreeRTOS_flush_logging( );
+ }
+ }
+ else
+ {
+ pxSegment = NULL;
+ }
+ }
+
+ if( pxSegment == NULL )
+ {
+ /* New messages: sent-out for the first time. Check current
+ sliding window size of peer. */
+ pxSegment = xTCPWindowPeekHead( &( pxWindow->xTxQueue ) );
+
+ if( pxSegment == NULL )
+ {
+ /* No segments queued. */
+ ulReturn = 0UL;
+ }
+ else if( ( pxWindow->u.bits.bSendFullSize != pdFALSE_UNSIGNED ) && ( pxSegment->lDataLength < pxSegment->lMaxLength ) )
+ {
+ /* A segment has been queued but the driver waits until it
+ has a full size of MSS. */
+ ulReturn = 0;
+ }
+ else if( prvTCPWindowTxHasSpace( pxWindow, ulWindowSize ) == pdFALSE )
+ {
+ /* Peer has no more space at this moment. */
+ ulReturn = 0;
+ }
+ else
+ {
+ /* Move it out of the Tx queue. */
+ pxSegment = xTCPWindowGetHead( &( pxWindow->xTxQueue ) );
+
+ /* Don't let pxHeadSegment point to this segment any more,
+ so no more data will be added. */
+ if( pxWindow->pxHeadSegment == pxSegment )
+ {
+ pxWindow->pxHeadSegment = NULL;
+ }
+
+ /* pxWindow->tx.highest registers the highest sequence
+ number in our transmission window. */
+ pxWindow->tx.ulHighestSequenceNumber = pxSegment->ulSequenceNumber + ( ( uint32_t ) pxSegment->lDataLength );
+
+ /* ...and more detailed logging */
+ if( ( xTCPWindowLoggingLevel >= 2 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "ulTCPWindowTxGet[%u,%u]: XmitQueue %ld bytes for sequence number %lu (ws %lu)\n",
+ pxWindow->usPeerPortNumber,
+ pxWindow->usOurPortNumber,
+ pxSegment->lDataLength,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulWindowSize ) );
+ FreeRTOS_flush_logging( );
+ }
+ }
+ }
+ }
+ else
+ {
+ /* There is a priority segment. It doesn't need any checking for
+ space or timeouts. */
+ if( xTCPWindowLoggingLevel != 0 )
+ {
+ FreeRTOS_debug_printf( ( "ulTCPWindowTxGet[%u,%u]: PrioQueue %ld bytes for sequence number %lu (ws %lu)\n",
+ pxWindow->usPeerPortNumber,
+ pxWindow->usOurPortNumber,
+ pxSegment->lDataLength,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulWindowSize ) );
+ FreeRTOS_flush_logging( );
+ }
+ }
+
+ /* See if it has already been determined to return 0. */
+ if( ulReturn != 0UL )
+ {
+ configASSERT( listLIST_ITEM_CONTAINER( &(pxSegment->xQueueItem ) ) == NULL );
+
+ /* Now that the segment will be transmitted, add it to the tail of
+ the waiting queue. */
+ vListInsertFifo( &pxWindow->xWaitQueue, &pxSegment->xQueueItem );
+
+ /* And mark it as outstanding. */
+ pxSegment->u.bits.bOutstanding = pdTRUE_UNSIGNED;
+
+ /* Administer the transmit count, needed for fast
+ retransmissions. */
+ ( pxSegment->u.bits.ucTransmitCount )++;
+
+ /* If there have been several retransmissions (4), decrease the
+ size of the transmission window to at most 2 times MSS. */
+ if( pxSegment->u.bits.ucTransmitCount == MAX_TRANSMIT_COUNT_USING_LARGE_WINDOW )
+ {
+ if( pxWindow->xSize.ulTxWindowLength > ( 2U * pxWindow->usMSS ) )
+ {
+ FreeRTOS_debug_printf( ( "ulTCPWindowTxGet[%u - %d]: Change Tx window: %lu -> %u\n",
+ pxWindow->usPeerPortNumber, pxWindow->usOurPortNumber,
+ pxWindow->xSize.ulTxWindowLength, 2 * pxWindow->usMSS ) );
+ pxWindow->xSize.ulTxWindowLength = ( 2UL * pxWindow->usMSS );
+ }
+ }
+
+ /* Clear the transmit timer. */
+ vTCPTimerSet( &( pxSegment->xTransmitTimer ) );
+
+ pxWindow->ulOurSequenceNumber = pxSegment->ulSequenceNumber;
+
+ /* Inform the caller where to find the data within the queue. */
+ *plPosition = pxSegment->lStreamPos;
+
+ /* And return the length of the data segment */
+ ulReturn = ( uint32_t ) pxSegment->lDataLength;
+ }
+
+ return ulReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static uint32_t prvTCPWindowTxCheckAck( TCPWindow_t *pxWindow, uint32_t ulFirst, uint32_t ulLast )
+ {
+ uint32_t ulBytesConfirmed = 0u;
+ uint32_t ulSequenceNumber = ulFirst, ulDataLength;
+ const ListItem_t *pxIterator;
+ const MiniListItem_t *pxEnd = ( const MiniListItem_t* )listGET_END_MARKER( &pxWindow->xTxSegments );
+ BaseType_t xDoUnlink;
+ TCPSegment_t *pxSegment;
+ /* An acknowledgement or a selective ACK (SACK) was received. See if some outstanding data
+ may be removed from the transmission queue(s).
+ All TX segments for which
+ ( ( ulSequenceNumber >= ulFirst ) && ( ulSequenceNumber < ulLast ) in a
+ contiguous block. Note that the segments are stored in xTxSegments in a
+ strict sequential order. */
+
+ /* SRTT[i] = (1-a) * SRTT[i-1] + a * RTT
+
+ 0 < a < 1; usually a = 1/8
+
+ RTO = 2 * SRTT
+
+ where:
+ RTT is Round Trip Time
+ SRTT is Smoothed RTT
+ RTO is Retransmit timeout
+
+ A Smoothed RTT will increase quickly, but it is conservative when
+ becoming smaller. */
+
+ for(
+ pxIterator = ( const ListItem_t * ) listGET_NEXT( pxEnd );
+ ( pxIterator != ( const ListItem_t * ) pxEnd ) && ( xSequenceLessThan( ulSequenceNumber, ulLast ) != 0 );
+ )
+ {
+ xDoUnlink = pdFALSE;
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+
+ /* Move to the next item because the current item might get
+ removed. */
+ pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator );
+
+ /* Continue if this segment does not fall within the ACK'd range. */
+ if( xSequenceGreaterThan( ulSequenceNumber, pxSegment->ulSequenceNumber ) != pdFALSE )
+ {
+ continue;
+ }
+
+ /* Is it ready? */
+ if( ulSequenceNumber != pxSegment->ulSequenceNumber )
+ {
+ break;
+ }
+
+ ulDataLength = ( uint32_t ) pxSegment->lDataLength;
+
+ if( pxSegment->u.bits.bAcked == pdFALSE_UNSIGNED )
+ {
+ if( xSequenceGreaterThan( pxSegment->ulSequenceNumber + ( uint32_t )ulDataLength, ulLast ) != pdFALSE )
+ {
+ /* What happens? Only part of this segment was accepted,
+ probably due to WND limits
+
+ AAAAAAA BBBBBBB << acked
+ aaaaaaa aaaa << sent */
+ #if( ipconfigHAS_DEBUG_PRINTF != 0 )
+ {
+ uint32_t ulFirstSeq = pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber;
+ FreeRTOS_debug_printf( ( "prvTCPWindowTxCheckAck[%u.%u]: %lu - %lu Partial sequence number %lu - %lu\n",
+ pxWindow->usPeerPortNumber,
+ pxWindow->usOurPortNumber,
+ ulFirstSeq - pxWindow->tx.ulFirstSequenceNumber,
+ ulLast - pxWindow->tx.ulFirstSequenceNumber,
+ ulFirstSeq, ulFirstSeq + ulDataLength ) );
+ }
+ #endif /* ipconfigHAS_DEBUG_PRINTF */
+ break;
+ }
+
+ /* This segment is fully ACK'd, set the flag. */
+ pxSegment->u.bits.bAcked = pdTRUE_UNSIGNED;
+
+ /* Calculate the RTT only if the segment was sent-out for the
+ first time and if this is the last ACK'd segment in a range. */
+ if( ( pxSegment->u.bits.ucTransmitCount == 1 ) && ( ( pxSegment->ulSequenceNumber + ulDataLength ) == ulLast ) )
+ {
+ int32_t mS = ( int32_t ) ulTimerGetAge( &( pxSegment->xTransmitTimer ) );
+
+ if( pxWindow->lSRTT >= mS )
+ {
+ /* RTT becomes smaller: adapt slowly. */
+ pxWindow->lSRTT = ( ( winSRTT_DECREMENT_NEW * mS ) + ( winSRTT_DECREMENT_CURRENT * pxWindow->lSRTT ) ) / ( winSRTT_DECREMENT_NEW + winSRTT_DECREMENT_CURRENT );
+ }
+ else
+ {
+ /* RTT becomes larger: adapt quicker */
+ pxWindow->lSRTT = ( ( winSRTT_INCREMENT_NEW * mS ) + ( winSRTT_INCREMENT_CURRENT * pxWindow->lSRTT ) ) / ( winSRTT_INCREMENT_NEW + winSRTT_INCREMENT_CURRENT );
+ }
+
+ /* Cap to the minimum of 50ms. */
+ if( pxWindow->lSRTT < winSRTT_CAP_mS )
+ {
+ pxWindow->lSRTT = winSRTT_CAP_mS;
+ }
+ }
+
+ /* Unlink it from the 3 queues, but do not destroy it (yet). */
+ xDoUnlink = pdTRUE;
+ }
+
+ /* pxSegment->u.bits.bAcked is now true. Is it located at the left
+ side of the transmission queue? If so, it may be freed. */
+ if( ulSequenceNumber == pxWindow->tx.ulCurrentSequenceNumber )
+ {
+ if( ( xTCPWindowLoggingLevel >= 2 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "prvTCPWindowTxCheckAck: %lu - %lu Ready sequence number %lu\n",
+ ulFirst - pxWindow->tx.ulFirstSequenceNumber,
+ ulLast - pxWindow->tx.ulFirstSequenceNumber,
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber ) );
+ }
+
+ /* Increase the left-hand value of the transmission window. */
+ pxWindow->tx.ulCurrentSequenceNumber += ulDataLength;
+
+ /* This function will return the number of bytes that the tail
+ of txStream may be advanced. */
+ ulBytesConfirmed += ulDataLength;
+
+ /* All segments below tx.ulCurrentSequenceNumber may be freed. */
+ vTCPWindowFree( pxSegment );
+
+ /* No need to unlink it any more. */
+ xDoUnlink = pdFALSE;
+ }
+
+ if( ( xDoUnlink != pdFALSE ) && ( listLIST_ITEM_CONTAINER( &( pxSegment->xQueueItem ) ) != NULL ) )
+ {
+ /* Remove item from its queues. */
+ uxListRemove( &pxSegment->xQueueItem );
+ }
+
+ ulSequenceNumber += ulDataLength;
+ }
+
+ return ulBytesConfirmed;
+ }
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ static uint32_t prvTCPWindowFastRetransmit( TCPWindow_t *pxWindow, uint32_t ulFirst )
+ {
+ const ListItem_t *pxIterator;
+ const MiniListItem_t* pxEnd;
+ TCPSegment_t *pxSegment;
+ uint32_t ulCount = 0UL;
+
+ /* A higher Tx block has been acknowledged. Now iterate through the
+ xWaitQueue to find a possible condition for a FAST retransmission. */
+
+ pxEnd = ( const MiniListItem_t* ) listGET_END_MARKER( &( pxWindow->xWaitQueue ) );
+
+ for( pxIterator = ( const ListItem_t * ) listGET_NEXT( pxEnd );
+ pxIterator != ( const ListItem_t * ) pxEnd; )
+ {
+ /* Get the owner, which is a TCP segment. */
+ pxSegment = ( TCPSegment_t * ) listGET_LIST_ITEM_OWNER( pxIterator );
+
+ /* Hop to the next item before the current gets unlinked. */
+ pxIterator = ( const ListItem_t * ) listGET_NEXT( pxIterator );
+
+ /* Fast retransmission:
+ When 3 packets with a higher sequence number have been acknowledged
+ by the peer, it is very unlikely a current packet will ever arrive.
+ It will be retransmitted far before the RTO. */
+ if( ( pxSegment->u.bits.bAcked == pdFALSE_UNSIGNED ) &&
+ ( xSequenceLessThan( pxSegment->ulSequenceNumber, ulFirst ) != pdFALSE ) &&
+ ( ++( pxSegment->u.bits.ucDupAckCount ) == DUPLICATE_ACKS_BEFORE_FAST_RETRANSMIT ) )
+ {
+ pxSegment->u.bits.ucTransmitCount = pdFALSE_UNSIGNED;
+
+ /* Not clearing 'ucDupAckCount' yet as more SACK's might come in
+ which might lead to a second fast rexmit. */
+ if( ( xTCPWindowLoggingLevel >= 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "prvTCPWindowFastRetransmit: Requeue sequence number %lu < %lu\n",
+ pxSegment->ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulFirst - pxWindow->tx.ulFirstSequenceNumber ) );
+ FreeRTOS_flush_logging( );
+ }
+
+ /* Remove it from xWaitQueue. */
+ uxListRemove( &pxSegment->xQueueItem );
+
+ /* Add this segment to the priority queue so it gets
+ retransmitted immediately. */
+ vListInsertFifo( &( pxWindow->xPriorityQueue ), &( pxSegment->xQueueItem ) );
+ ulCount++;
+ }
+ }
+
+ return ulCount;
+ }
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ uint32_t ulTCPWindowTxAck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber )
+ {
+ uint32_t ulFirstSequence, ulReturn;
+
+ /* Receive a normal ACK. */
+
+ ulFirstSequence = pxWindow->tx.ulCurrentSequenceNumber;
+
+ if( xSequenceLessThanOrEqual( ulSequenceNumber, ulFirstSequence ) != pdFALSE )
+ {
+ ulReturn = 0UL;
+ }
+ else
+ {
+ ulReturn = prvTCPWindowTxCheckAck( pxWindow, ulFirstSequence, ulSequenceNumber );
+ }
+
+ return ulReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 1 )
+
+ uint32_t ulTCPWindowTxSack( TCPWindow_t *pxWindow, uint32_t ulFirst, uint32_t ulLast )
+ {
+ uint32_t ulAckCount = 0UL;
+ uint32_t ulCurrentSequenceNumber = pxWindow->tx.ulCurrentSequenceNumber;
+
+ /* Receive a SACK option. */
+ ulAckCount = prvTCPWindowTxCheckAck( pxWindow, ulFirst, ulLast );
+ prvTCPWindowFastRetransmit( pxWindow, ulFirst );
+
+ if( ( xTCPWindowLoggingLevel >= 1 ) && ( xSequenceGreaterThan( ulFirst, ulCurrentSequenceNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "ulTCPWindowTxSack[%u,%u]: from %lu to %lu (ack = %lu)\n",
+ pxWindow->usPeerPortNumber,
+ pxWindow->usOurPortNumber,
+ ulFirst - pxWindow->tx.ulFirstSequenceNumber,
+ ulLast - pxWindow->tx.ulFirstSequenceNumber,
+ pxWindow->tx.ulCurrentSequenceNumber - pxWindow->tx.ulFirstSequenceNumber ) );
+ FreeRTOS_flush_logging( );
+ }
+
+ return ulAckCount;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 1 */
+/*-----------------------------------------------------------*/
+
+/*
+##### # ##### #### ######
+# # # # # # # # # # #
+ # # # # # #
+ # ### ##### # # # # # #
+ # # # # # # # # #####
+ # # # # # # #### # # #
+ # # # # # # # # # #
+ # # # # #### # # # #
+ #### ##### # # # #### #### ####
+ #
+ ###
+*/
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ int32_t lTCPWindowRxCheck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber, uint32_t ulLength, uint32_t ulSpace )
+ {
+ int32_t iReturn;
+
+ /* Data was received at 'ulSequenceNumber'. See if it was expected
+ and if there is enough space to store the new data. */
+ if( ( pxWindow->rx.ulCurrentSequenceNumber != ulSequenceNumber ) || ( ulSpace < ulLength ) )
+ {
+ iReturn = -1;
+ }
+ else
+ {
+ pxWindow->rx.ulCurrentSequenceNumber += ( uint32_t ) ulLength;
+ iReturn = 0;
+ }
+
+ return iReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ int32_t lTCPWindowTxAdd( TCPWindow_t *pxWindow, uint32_t ulLength, int32_t lPosition, int32_t lMax )
+ {
+ TCPSegment_t *pxSegment = &( pxWindow->xTxSegment );
+ int32_t lResult;
+
+ /* Data is being scheduled for transmission. */
+
+ /* lMax would indicate the size of the txStream. */
+ ( void ) lMax;
+ /* This is tiny TCP: there is only 1 segment for outgoing data.
+ As long as 'lDataLength' is unequal to zero, the segment is still occupied. */
+ if( pxSegment->lDataLength > 0 )
+ {
+ lResult = 0L;
+ }
+ else
+ {
+ if( ulLength > ( uint32_t ) pxSegment->lMaxLength )
+ {
+ if( ( xTCPWindowLoggingLevel != 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowTxAdd: can only store %ld / %ld bytes\n", ulLength, pxSegment->lMaxLength ) );
+ }
+
+ ulLength = ( uint32_t ) pxSegment->lMaxLength;
+ }
+
+ if( ( xTCPWindowLoggingLevel != 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "lTCPWindowTxAdd: SeqNr %ld (%ld) Len %ld\n",
+ pxWindow->ulNextTxSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxWindow->tx.ulCurrentSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulLength ) );
+ }
+
+ /* The sequence number of the first byte in this packet. */
+ pxSegment->ulSequenceNumber = pxWindow->ulNextTxSequenceNumber;
+ pxSegment->lDataLength = ( int32_t ) ulLength;
+ pxSegment->lStreamPos = lPosition;
+ pxSegment->u.ulFlags = 0UL;
+ vTCPTimerSet( &( pxSegment->xTransmitTimer ) );
+
+ /* Increase the sequence number of the next data to be stored for
+ transmission. */
+ pxWindow->ulNextTxSequenceNumber += ulLength;
+ lResult = ( int32_t )ulLength;
+ }
+
+ return lResult;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ uint32_t ulTCPWindowTxGet( TCPWindow_t *pxWindow, uint32_t ulWindowSize, int32_t *plPosition )
+ {
+ TCPSegment_t *pxSegment = &( pxWindow->xTxSegment );
+ uint32_t ulLength = ( uint32_t ) pxSegment->lDataLength;
+ uint32_t ulMaxTime;
+
+ if( ulLength != 0UL )
+ {
+ /* _HT_ Still under investigation */
+ ( void ) ulWindowSize;
+
+ if( pxSegment->u.bits.bOutstanding != pdFALSE_UNSIGNED )
+ {
+ /* As 'ucTransmitCount' has a minimum of 1, take 2 * RTT */
+ ulMaxTime = ( ( uint32_t ) 1u << pxSegment->u.bits.ucTransmitCount ) * ( ( uint32_t ) pxWindow->lSRTT );
+
+ if( ulTimerGetAge( &( pxSegment->xTransmitTimer ) ) < ulMaxTime )
+ {
+ ulLength = 0ul;
+ }
+ }
+
+ if( ulLength != 0ul )
+ {
+ pxSegment->u.bits.bOutstanding = pdTRUE_UNSIGNED;
+ pxSegment->u.bits.ucTransmitCount++;
+ vTCPTimerSet (&pxSegment->xTransmitTimer);
+ pxWindow->ulOurSequenceNumber = pxSegment->ulSequenceNumber;
+ *plPosition = pxSegment->lStreamPos;
+ }
+ }
+
+ return ulLength;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ BaseType_t xTCPWindowTxDone( TCPWindow_t *pxWindow )
+ {
+ BaseType_t xReturn;
+
+ /* Has the outstanding data been sent because user wants to shutdown? */
+ if( pxWindow->xTxSegment.lDataLength == 0 )
+ {
+ xReturn = pdTRUE;
+ }
+ else
+ {
+ xReturn = pdFALSE;
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize );
+ static BaseType_t prvTCPWindowTxHasSpace( TCPWindow_t *pxWindow, uint32_t ulWindowSize )
+ {
+ BaseType_t xReturn;
+
+ if( ulWindowSize >= pxWindow->usMSSInit )
+ {
+ xReturn = pdTRUE;
+ }
+ else
+ {
+ xReturn = pdFALSE;
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ BaseType_t xTCPWindowTxHasData( TCPWindow_t *pxWindow, uint32_t ulWindowSize, TickType_t *pulDelay )
+ {
+ TCPSegment_t *pxSegment = &( pxWindow->xTxSegment );
+ BaseType_t xReturn;
+ TickType_t ulAge, ulMaxAge;
+
+ /* Check data to be sent. */
+ *pulDelay = ( TickType_t ) 0;
+ if( pxSegment->lDataLength == 0 )
+ {
+ /* Got nothing to send right now. */
+ xReturn = pdFALSE;
+ }
+ else
+ {
+ if( pxSegment->u.bits.bOutstanding != pdFALSE_UNSIGNED )
+ {
+ ulAge = ulTimerGetAge ( &pxSegment->xTransmitTimer );
+ ulMaxAge = ( ( TickType_t ) 1u << pxSegment->u.bits.ucTransmitCount ) * ( ( uint32_t ) pxWindow->lSRTT );
+
+ if( ulMaxAge > ulAge )
+ {
+ *pulDelay = ulMaxAge - ulAge;
+ }
+
+ xReturn = pdTRUE;
+ }
+ else if( prvTCPWindowTxHasSpace( pxWindow, ulWindowSize ) == pdFALSE )
+ {
+ /* Too many outstanding messages. */
+ xReturn = pdFALSE;
+ }
+ else
+ {
+ xReturn = pdTRUE;
+ }
+ }
+
+ return xReturn;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ uint32_t ulTCPWindowTxAck( TCPWindow_t *pxWindow, uint32_t ulSequenceNumber )
+ {
+ TCPSegment_t *pxSegment = &( pxWindow->xTxSegment );
+ uint32_t ulDataLength = ( uint32_t ) pxSegment->lDataLength;
+
+ /* Receive a normal ACK */
+
+ if( ulDataLength != 0ul )
+ {
+ if( ulSequenceNumber < ( pxWindow->tx.ulCurrentSequenceNumber + ulDataLength ) )
+ {
+ if( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE )
+ {
+ FreeRTOS_debug_printf( ( "win_tx_ack: acked %ld expc %ld len %ld\n",
+ ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ pxWindow->tx.ulCurrentSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulDataLength ) );
+ }
+
+ /* Nothing to send right now. */
+ ulDataLength = 0ul;
+ }
+ else
+ {
+ pxWindow->tx.ulCurrentSequenceNumber += ulDataLength;
+
+ if( ( xTCPWindowLoggingLevel != 0 ) && ( ipconfigTCP_MAY_LOG_PORT( pxWindow->usOurPortNumber ) != pdFALSE ) )
+ {
+ FreeRTOS_debug_printf( ( "win_tx_ack: acked seqnr %ld len %ld\n",
+ ulSequenceNumber - pxWindow->tx.ulFirstSequenceNumber,
+ ulDataLength ) );
+ }
+
+ pxSegment->lDataLength = 0;
+ }
+ }
+
+ return ulDataLength;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ BaseType_t xTCPWindowRxEmpty( TCPWindow_t *pxWindow )
+ {
+ /* Return true if 'ulCurrentSequenceNumber >= ulHighestSequenceNumber'
+ 'ulCurrentSequenceNumber' is the highest sequence number stored,
+ 'ulHighestSequenceNumber' is the highest sequence number seen. */
+ return xSequenceGreaterThanOrEqual( pxWindow->rx.ulCurrentSequenceNumber, pxWindow->rx.ulHighestSequenceNumber );
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+#if( ipconfigUSE_TCP_WIN == 0 )
+
+ /* Destroy a window (always returns NULL) */
+ void vTCPWindowDestroy( TCPWindow_t *pxWindow )
+ {
+ /* As in tiny TCP there are no shared segments descriptors, there is
+ nothing to release. */
+ ( void ) pxWindow;
+ }
+
+#endif /* ipconfigUSE_TCP_WIN == 0 */
+/*-----------------------------------------------------------*/
+
+
|