Update FreeRTOS_get_tx_head to create TX stream if not created already (#1023)

* TCP zero copy update FreeRTOS_get_tx_head()

* fix unit tests

* Uncrustify: triggered by comment

* updating with review feedback

---------

Co-authored-by: GitHub Action <[email protected]>

Author: tony-josi-aws

source/FreeRTOS_Sockets.c

@@ -4372,11 +4372,11 @@ void vSocketWakeUpUser( FreeRTOS_Socket_t * pxSocket )
  * @return Head of the circular transmit buffer if all checks pass. Or else, NULL
  *         is returned.
  */
-    uint8_t * FreeRTOS_get_tx_head( ConstSocket_t xSocket,
+    uint8_t * FreeRTOS_get_tx_head( Socket_t xSocket,
                                     BaseType_t * pxLength )
     {
         uint8_t * pucReturn = NULL;
-        const FreeRTOS_Socket_t * pxSocket = ( const FreeRTOS_Socket_t * ) xSocket;
+        FreeRTOS_Socket_t * pxSocket = ( FreeRTOS_Socket_t * ) xSocket;
         StreamBuffer_t * pxBuffer = NULL;
 
         *pxLength = 0;
@@ -4387,6 +4387,13 @@ void vSocketWakeUpUser( FreeRTOS_Socket_t * pxSocket )
         {
             pxBuffer = pxSocket->u.xTCP.txStream;
 
+            if( ( pxBuffer == NULL ) && ( pxSocket->u.xTCP.bits.bMallocError != pdTRUE_UNSIGNED ) )
+            {
+                /* Create the outgoing stream only when it is needed */
+                ( void ) prvTCPCreateStream( pxSocket, pdFALSE );
+                pxBuffer = pxSocket->u.xTCP.txStream;
+            }
+
             if( pxBuffer != NULL )
             {
                 size_t uxSpace = uxStreamBufferGetSpace( pxBuffer );
@@ -5050,7 +5057,7 @@ void vSocketWakeUpUser( FreeRTOS_Socket_t * pxSocket )
         if( pxBuffer == NULL )
         {
             FreeRTOS_debug_printf( ( "prvTCPCreateStream: malloc failed\n" ) );
-            pxSocket->u.xTCP.bits.bMallocError = pdTRUE;
+            pxSocket->u.xTCP.bits.bMallocError = pdTRUE_UNSIGNED;
             vTCPStateChange( pxSocket, eCLOSE_WAIT );
         }
         else

source/include/FreeRTOS_Sockets.h

@@ -370,7 +370,7 @@
 /* For advanced applications only:
  * Get a direct pointer to the circular transmit buffer.
  * '*pxLength' will contain the number of bytes that may be written. */
-        uint8_t * FreeRTOS_get_tx_head( ConstSocket_t xSocket,
+        uint8_t * FreeRTOS_get_tx_head( Socket_t xSocket,
                                         BaseType_t * pxLength );
 
 /* For the web server: borrow the circular Rx buffer for inspection

test/unit-test/FreeRTOS_Sockets/FreeRTOS_Sockets_TCP_API_utest.c

@@ -794,11 +794,48 @@ void test_FreeRTOS_get_tx_head_InvalidParams( void )
     /* NULL socket. */
     pucReturn = FreeRTOS_get_tx_head( NULL, &xLength );
     TEST_ASSERT_EQUAL( NULL, pucReturn );
+}
+
+/**
+ * @brief Socket with stream not yet created is passed to the function.
+ */
+void test_FreeRTOS_get_tx_head_NoStream( void )
+{
+    uint8_t * pucReturn;
+    FreeRTOS_Socket_t xSocket;
+    BaseType_t xLength;
+    uint8_t ucStream[ ipconfigTCP_MSS ];
+    const size_t uxRemainingSize = 5;
+
+    memset( &xSocket, 0, sizeof( xSocket ) );
+    memset( ucStream, 0, ipconfigTCP_MSS );
 
     /* NULL stream. */
     xSocket.ucProtocol = FREERTOS_IPPROTO_TCP;
+    pvPortMalloc_ExpectAnyArgsAndReturn( ucStream );
+    uxStreamBufferGetSpace_ExpectAndReturn( ( StreamBuffer_t * ) ucStream, uxRemainingSize );
     pucReturn = FreeRTOS_get_tx_head( &xSocket, &xLength );
-    TEST_ASSERT_EQUAL( NULL, pucReturn );
+    TEST_ASSERT_EQUAL_PTR( &( ( ( StreamBuffer_t * ) ucStream )->ucArray[ 0 ] ), pucReturn );
+    TEST_ASSERT_EQUAL( uxRemainingSize, xLength );
+}
+
+/**
+ * @brief Socket with stream not created but malloc failed previously.
+ */
+void test_FreeRTOS_get_tx_head_NoStreamMallocError( void )
+{
+    uint8_t * pucReturn;
+    FreeRTOS_Socket_t xSocket;
+    BaseType_t xLength;
+
+    memset( &xSocket, 0, sizeof( xSocket ) );
+
+    /* NULL stream. */
+    xSocket.ucProtocol = FREERTOS_IPPROTO_TCP;
+    xSocket.u.xTCP.bits.bMallocError = pdTRUE_UNSIGNED;
+    pucReturn = FreeRTOS_get_tx_head( &xSocket, &xLength );
+    TEST_ASSERT_EQUAL_PTR( NULL, pucReturn );
+    TEST_ASSERT_EQUAL( 0, xLength );
 }
 
 /**

test/unit-test/FreeRTOS_Sockets/FreeRTOS_Sockets_privates_utest.c

@@ -2296,14 +2296,14 @@ void test_prvTCPSendCheck_InvalidValues( void )
     TEST_ASSERT_EQUAL( -pdFREERTOS_ERRNO_EINVAL, lReturn );
 
     /* No memory. */
-    xSocket.u.xTCP.bits.bMallocError = pdTRUE;
+    xSocket.u.xTCP.bits.bMallocError = pdTRUE_UNSIGNED;
     xSocket.ucProtocol = FREERTOS_IPPROTO_TCP;
     listLIST_ITEM_CONTAINER_ExpectAnyArgsAndReturn( &xBoundTCPSocketsList );
     lReturn = prvTCPSendCheck( &xSocket, uxDataLength );
     TEST_ASSERT_EQUAL( -pdFREERTOS_ERRNO_ENOMEM, lReturn );
 
     /* Invalid states. */
-    xSocket.u.xTCP.bits.bMallocError = pdFALSE;
+    xSocket.u.xTCP.bits.bMallocError = pdFALSE_UNSIGNED;
     xSocket.ucProtocol = FREERTOS_IPPROTO_TCP;
 
     for( unsigned int i = 0; i < sizeof( array ) / sizeof( eIPTCPState_t ); i++ )