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Update RX sequence number after refusing TCP FIN packet. #1195

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Merged
merged 4 commits into from
Oct 7, 2024
Merged

Update RX sequence number after refusing TCP FIN packet. #1195

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520d713
Update RX sequence number after refusing TCP FIN packet.
ActoryOu Oct 3, 2024
0c2aee3
Merge branch 'main' into UpdateSeqAfterRefuseFin
aggarg Oct 3, 2024
b1403c8
Add UT
ActoryOu Oct 3, 2024
3584bb8
Fix link check
aggarg Oct 7, 2024
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32 changes: 20 additions & 12 deletions source/FreeRTOS_TCP_State_Handling.c
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Original file line number Diff line number Diff line change
Expand Up @@ -584,6 +584,8 @@
{
/* Peer is requesting to stop, see if we're really finished. */
xMayClose = pdTRUE;
ulIntermediateResult = ulSequenceNumber + ulReceiveLength - pxTCPWindow->rx.ulCurrentSequenceNumber;
lDistance = ( int32_t ) ulIntermediateResult;

/* Checks are only necessary if we haven't sent a FIN yet. */
if( pxSocket->u.xTCP.bits.bFinSent == pdFALSE_UNSIGNED )
Expand All @@ -601,22 +603,28 @@
( int ) bRxComplete,
( int ) bTxDone ) );
xMayClose = pdFALSE;
}
else
{
ulIntermediateResult = ulSequenceNumber + ulReceiveLength - pxTCPWindow->rx.ulCurrentSequenceNumber;
lDistance = ( int32_t ) ulIntermediateResult;

if( lDistance > 1 )
/* This action is necessary to ensure proper handling of any subsequent packets that
* may arrive after the refused FIN packet. Note that we only update it when the sequence
* of FIN packet is correct. Otherwise, we wait for re-transmission. */
if( lDistance <= 1 )
{
FreeRTOS_debug_printf( ( "Refusing FIN: Rx not complete %d (cur %u high %u)\n",
( int ) lDistance,
( unsigned ) ( pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ),
( unsigned ) ( pxTCPWindow->rx.ulHighestSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ) ) );

xMayClose = pdFALSE;
pxTCPWindow->rx.ulCurrentSequenceNumber = pxTCPWindow->rx.ulFINSequenceNumber + 1U;
}
}
else if( lDistance > 1 )
{
FreeRTOS_debug_printf( ( "Refusing FIN: Rx not complete %d (cur %u high %u)\n",
( int ) lDistance,
( unsigned ) ( pxTCPWindow->rx.ulCurrentSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ),
( unsigned ) ( pxTCPWindow->rx.ulHighestSequenceNumber - pxTCPWindow->rx.ulFirstSequenceNumber ) ) );

xMayClose = pdFALSE;
}
else
{
/* Empty else marker. */
}
}

if( xTCPWindowLoggingLevel > 0 )
Expand Down
43 changes: 42 additions & 1 deletion test/unit-test/FreeRTOS_TCP_State_Handling/FreeRTOS_TCP_State_Handling_utest.c
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Original file line number Diff line number Diff line change
Expand Up @@ -821,6 +821,47 @@ void test_prvHandleEstablished_FINNotSentRXComplete( void )
TEST_ASSERT_EQUAL( 40, xSendLength );
}

/**
* @brief Data left for receiving when receiving TCP packet with FIN/ACK.
*/
void test_prvHandleEstablished_FINNotSentRXNotCompleteNotExpectedSeq( void )
{
BaseType_t xSendLength = 0;

pxSocket = &xSocket;

pxNetworkBuffer = &xNetworkBuffer;
pxNetworkBuffer->pucEthernetBuffer = ucEthernetBuffer;

/* Map the buffer onto the ProtocolHeader_t struct for easy access to the fields. */
ProtocolHeaders_t * pxProtocolHeaders = ( ( ProtocolHeaders_t * )
&( pxNetworkBuffer->pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv4_HEADER ] ) );
TCPHeader_t * pxTCPHeader = &pxProtocolHeaders->xTCPHeader;
TCPWindow_t * pxTCPWindow = &pxSocket->u.xTCP.xTCPWindow;

ulCalled = 0;
pxTCPHeader->ucTCPFlags = tcpTCP_FLAG_FIN | tcpTCP_FLAG_ACK;
pxTCPHeader->ulSequenceNumber = FreeRTOS_htonl( 1502 );
pxTCPHeader->usWindow = 1000;
pxSocket->u.xTCP.txStream = ( StreamBuffer_t * ) 0x12345678;
pxSocket->u.xTCP.pxHandleSent = NULL;
pxSocket->u.xTCP.bits.bFinSent = pdFALSE;
pxTCPWindow->rx.ulCurrentSequenceNumber = 1500;

uxIPHeaderSizeSocket_IgnoreAndReturn( ipSIZE_OF_IPv4_HEADER );
ulTCPWindowTxAck_ExpectAnyArgsAndReturn( 0 );
prvTCPAddTxData_ExpectAnyArgs();
xTCPWindowRxEmpty_ExpectAnyArgsAndReturn( pdFALSE );
xTCPWindowTxDone_ExpectAnyArgsAndReturn( pdTRUE );
prvTCPPrepareSend_ExpectAnyArgsAndReturn( 0 );

xSendLength = prvHandleEstablished( pxSocket,
&pxNetworkBuffer,
0,
0 );
TEST_ASSERT_EQUAL( 0, xSendLength );
}

/**
* @brief Data left for receiving when receiving TCP packet with FIN/ACK.
*/
Expand All @@ -846,7 +887,7 @@ void test_prvHandleEstablished_FINNotSentRXNotComplete( void )
pxSocket->u.xTCP.txStream = ( StreamBuffer_t * ) 0x12345678;
pxSocket->u.xTCP.pxHandleSent = NULL;
pxSocket->u.xTCP.bits.bFinSent = pdFALSE;
pxTCPWindow->rx.ulCurrentSequenceNumber = 2501;
pxTCPWindow->rx.ulCurrentSequenceNumber = 1500;

uxIPHeaderSizeSocket_IgnoreAndReturn( ipSIZE_OF_IPv4_HEADER );
ulTCPWindowTxAck_ExpectAnyArgsAndReturn( 0 );
Expand Down
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