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Fix incorrect state transition #1302

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Fix incorrect state transition #1302

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ac7ea71
Fix incorrect TCP state transition on connection timeout
Fr3ya Nov 21, 2025
ef44afe
Update unit tests and coverage based on maintainer feedback
Fr3ya Dec 5, 2025
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3 changes: 2 additions & 1 deletion source/FreeRTOS_TCP_IP.c
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Original file line number Diff line number Diff line change
Expand Up @@ -324,7 +324,8 @@
if( ( ( xPreviousState == eCONNECT_SYN ) ||
( xPreviousState == eSYN_FIRST ) ||
( xPreviousState == eSYN_RECEIVED ) ) &&
( eTCPState == eCLOSE_WAIT ) )
( ( eTCPState == eCLOSE_WAIT ) ||
( eTCPState == eCLOSED ) ) )
{
/* A socket was in the connecting phase but something
* went wrong and it should be closed. */
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4 changes: 2 additions & 2 deletions source/FreeRTOS_TCP_Transmission.c
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Original file line number Diff line number Diff line change
Expand Up @@ -132,11 +132,11 @@
{
/* The connection is in the SYN status. The packet will be repeated
* to most 3 times. When there is no response, the socket get the
* status 'eCLOSE_WAIT'. */
* status 'eCLOSED'. */
FreeRTOS_debug_printf( ( "Connect: giving up %xip:%u\n",
( unsigned ) pxSocket->u.xTCP.xRemoteIP.ulIP_IPv4, /* IP address of remote machine. */
pxSocket->u.xTCP.usRemotePort ) ); /* Port on remote machine. */
vTCPStateChange( pxSocket, eCLOSE_WAIT );
vTCPStateChange( pxSocket, eCLOSED );
}
else if( prvTCPMakeSurePrepared( pxSocket ) == pdTRUE )
{
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78 changes: 55 additions & 23 deletions test/unit-test/FreeRTOS_TCP_IP/FreeRTOS_TCP_IP_utest.c
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Original file line number Diff line number Diff line change
Expand Up @@ -802,29 +802,60 @@ void test_vTCPStateChange_ClosedWaitState_PrvStateSyn( void )
enum eTCP_STATE eTCPState;
BaseType_t xTickCountAck = 0xAABBEEDD;
BaseType_t xTickCountAlive = 0xAABBEFDD;

memset( &xSocket, 0, sizeof( xSocket ) );
eTCPState = eCLOSE_WAIT;

xSocket.u.xTCP.eTCPState = eCONNECT_SYN;

prvTCPSocketIsActive_ExpectAndReturn( xSocket.u.xTCP.eTCPState, pdTRUE );
vTaskSuspendAll_Expect();
xTaskResumeAll_ExpectAndReturn( 0 );
xTaskGetTickCount_ExpectAndReturn( xTickCountAck );
xTaskGetTickCount_ExpectAndReturn( xTickCountAlive );
FreeRTOS_inet_ntop_ExpectAnyArgsAndReturn( NULL );

vSocketWakeUpUser_Expect( &xSocket );

vTCPStateChange( &xSocket, eTCPState );

TEST_ASSERT_EQUAL( eCLOSE_WAIT, xSocket.u.xTCP.eTCPState );
TEST_ASSERT_EQUAL( xTickCountAck, xSocket.u.xTCP.xLastActTime );
TEST_ASSERT_EQUAL( pdFALSE_UNSIGNED, xSocket.u.xTCP.bits.bWaitKeepAlive );
TEST_ASSERT_EQUAL( pdFALSE_UNSIGNED, xSocket.u.xTCP.bits.bSendKeepAlive );
TEST_ASSERT_EQUAL( 0, xSocket.u.xTCP.ucKeepRepCount );
TEST_ASSERT_EQUAL( xTickCountAlive, xSocket.u.xTCP.xLastAliveTime );
BaseType_t xRound;

/* See Fix incorrect state transition #1302, see RFC 793.
* A changes in state transition:
* Before: eSYN_FIRST -> eCLOSE_WAIT
* After : eSYN_FIRST -> eCLOSED
* For example, a TCP client trying to connect to a remote
* device, reaching a time-out.
*/
for( xRound = 0; xRound < 3; xRound++ )
{
memset( &xSocket, 0, sizeof( xSocket ) );
/* The socket was in a SYN state, e.g. eSYN_FIRST. */
xSocket.u.xTCP.eTCPState = eSYN_FIRST;

switch( xRound )
{
/* Check eSYN_FIRST to eCLOSED: */
case 0:
eTCPState = eCLOSED;
break;
/* Check eSYN_FIRST to eCLOSE_WAIT: */
case 1:
eTCPState = eCLOSE_WAIT;
break;
/* Check eSYN_FIRST to eSYN_RECEIVED: */
case 2:
eTCPState = eSYN_RECEIVED;
break;
}

if( xRound < 2 )
{
prvTCPSocketIsActive_ExpectAndReturn( xSocket.u.xTCP.eTCPState, pdTRUE );
vTaskSuspendAll_Expect();
xTaskResumeAll_ExpectAndReturn( 0 );
}

xTaskGetTickCount_ExpectAndReturn( xTickCountAck );
xTaskGetTickCount_ExpectAndReturn( xTickCountAlive );

FreeRTOS_inet_ntop_ExpectAnyArgsAndReturn( NULL );

vSocketWakeUpUser_Expect( &xSocket );

vTCPStateChange( &xSocket, eTCPState );

TEST_ASSERT_EQUAL( eTCPState, xSocket.u.xTCP.eTCPState );
TEST_ASSERT_EQUAL( xTickCountAck, xSocket.u.xTCP.xLastActTime );
TEST_ASSERT_EQUAL( pdFALSE_UNSIGNED, xSocket.u.xTCP.bits.bWaitKeepAlive );
TEST_ASSERT_EQUAL( pdFALSE_UNSIGNED, xSocket.u.xTCP.bits.bSendKeepAlive );
TEST_ASSERT_EQUAL( 0, xSocket.u.xTCP.ucKeepRepCount );
TEST_ASSERT_EQUAL( xTickCountAlive, xSocket.u.xTCP.xLastAliveTime );
}
}

/**
Expand Down Expand Up @@ -2210,6 +2241,7 @@ void test_xProcessReceivedTCPPacket_ConnectSyn_State_Rst_Change_State( void )
uxIPHeaderSizePacket_ExpectAnyArgsAndReturn( ipSIZE_OF_IPv4_HEADER );
pxTCPSocketLookup_ExpectAnyArgsAndReturn( pxSocket );
prvTCPSocketIsActive_ExpectAnyArgsAndReturn( pdTRUE );
prvTCPSocketIsActive_ExpectAnyArgsAndReturn( pdTRUE );
vTaskSuspendAll_Expect();
xTaskResumeAll_ExpectAndReturn( 0 );
xTaskGetTickCount_ExpectAndReturn( 1000 );
Expand Down