Update unused headers and NULL checks for platform wrappers (#367)

- Remove unused headers in the plaintext FreeRTOS sockets wrapper
- Update MFLN even though the preceding optional configuration returned an mbedTLS error
- Remove an unused `NULL` check in a private method that is already checked by the public connect method
- Add a `NULL` check to the public disconnect method

Co-authored-by: Joseph Julicher <jjulicher@mac.com>

FreeRTOS-Plus/Source/Application-Protocols/platform/freertos/transport/src/plaintext_freertos.c

@@ -24,8 +24,6 @@
 
 /* FreeRTOS includes. */
 #include "FreeRTOS.h"
-#include "atomic.h"
-#include "semphr.h"
 
 /* FreeRTOS+TCP includes. */
 #include "FreeRTOS_IP.h"

FreeRTOS-Plus/Source/Application-Protocols/platform/freertos/transport/src/tls_freertos.c

@@ -328,12 +328,9 @@ static int32_t setCredentials( SSLContext_t * pSslContext,
     mbedtls_ssl_conf_cert_profile( &( pSslContext->config ),
                                    &( pSslContext->certProfile ) );
 
-    if( pNetworkCredentials->pRootCa != NULL )
-    {
     mbedtlsError = setRootCa( pSslContext,
                               pNetworkCredentials->pRootCa,
                               pNetworkCredentials->rootCaSize );
-    }
 
     if( ( pNetworkCredentials->pClientCert != NULL ) &&
         ( pNetworkCredentials->pPrivateKey != NULL ) )
@@ -405,8 +402,7 @@ static void setOptionalConfigurations( SSLContext_t * pSslContext,
 
     /* Set Maximum Fragment Length if enabled. */
     #ifdef MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
-    if( 0 == mbedtlsError )
+
-    {
         /* Enable the max fragment extension. 4096 bytes is currently the largest fragment size permitted.
          * See RFC 8449 https://tools.ietf.org/html/rfc8449 for more information.
          *
@@ -420,9 +416,7 @@ static void setOptionalConfigurations( SSLContext_t * pSslContext,
                         mbedtlsHighLevelCodeOrDefault( mbedtlsError ),
                         mbedtlsLowLevelCodeOrDefault( mbedtlsError ) ) );
         }
-    }
+    #endif /* ifdef MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
-    #endif
-
 }
 /*-----------------------------------------------------------*/
 
@@ -671,15 +665,17 @@ TlsTransportStatus_t TLS_FreeRTOS_Connect( NetworkContext_t * pNetworkContext,
 
     /* Clean up on failure. */
     if( returnStatus != TLS_TRANSPORT_SUCCESS )
+    {
+        if( pNetworkContext != NULL )
         {
             sslContextFree( &( pNetworkContext->sslContext ) );
 
-        if( ( pNetworkContext != NULL ) &&
+            if( pNetworkContext->tcpSocket != FREERTOS_INVALID_SOCKET )
-            ( pNetworkContext->tcpSocket != FREERTOS_INVALID_SOCKET ) )
             {
                 ( void ) FreeRTOS_closesocket( pNetworkContext->tcpSocket );
             }
         }
+    }
     else
     {
         LogInfo( ( "(Network connection %p) Connection to %s established.",
@@ -695,6 +691,8 @@ void TLS_FreeRTOS_Disconnect( NetworkContext_t * pNetworkContext )
 {
     BaseType_t tlsStatus = 0;
 
+    if( pNetworkContext != NULL )
+    {
         /* Attempting to terminate TLS connection. */
         tlsStatus = ( BaseType_t ) mbedtls_ssl_close_notify( &( pNetworkContext->sslContext.context ) );
 
@@ -729,6 +727,7 @@ void TLS_FreeRTOS_Disconnect( NetworkContext_t * pNetworkContext )
 
         /* Free mbed TLS contexts. */
         sslContextFree( &( pNetworkContext->sslContext ) );
+    }
 
     /* Clear the mutex functions for mbed TLS thread safety. */
     mbedtls_threading_free_alt();

FreeRTOS-Plus/Source/Application-Protocols/platform/freertos/transport/src/tls_freertos_pkcs11.c

@@ -412,7 +412,7 @@ static TlsTransportStatus_t tlsSetup( NetworkContext_t * pNetworkContext,
                 returnStatus = TLS_TRANSPORT_INTERNAL_ERROR;
             }
         }
-    #endif
+    #endif /* ifdef MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
     if( returnStatus == TLS_TRANSPORT_SUCCESS )
     {
@@ -853,6 +853,8 @@ void TLS_FreeRTOS_Disconnect( NetworkContext_t * pNetworkContext )
 {
     BaseType_t tlsStatus = 0;
 
+    if( pNetworkContext != NULL )
+    {
         /* Attempting to terminate TLS connection. */
         tlsStatus = ( BaseType_t ) mbedtls_ssl_close_notify( &( pNetworkContext->sslContext.context ) );
 
@@ -887,6 +889,7 @@ void TLS_FreeRTOS_Disconnect( NetworkContext_t * pNetworkContext )
 
         /* Free mbed TLS contexts. */
         sslContextFree( &( pNetworkContext->sslContext ) );
+    }
 
     /* Clear the mutex functions for mbed TLS thread safety. */
     mbedtls_threading_free_alt();