Adds const keywords

Signed-off-by: Martin Melik Merkumians <melik-merkumians@acin.tuwien.ac.at>

source/src/cip/cipassembly.c

@@ -85,7 +85,7 @@ void ShutdownAssemblies(void) {
   if(NULL != assembly_class) {
     const CipInstance *instance = assembly_class->instances;
     while(NULL != instance) {
-      CipAttributeStruct *attribute = GetCipAttribute(instance, 3);
+      const CipAttributeStruct *const attribute = GetCipAttribute(instance, 3);
       if(NULL != attribute) {
         CipFree(attribute->data);
       }

source/src/cip/cipclass3connection.c

@@ -24,7 +24,7 @@ void Class3ConnectionTimeoutHandler(CipConnectionObject *connection_object) {
 
 /**** Implementation ****/
 CipError EstablishClass3Connection(
-  CipConnectionObject *RESTRICT const connection_object,
+  const CipConnectionObject *RESTRICT const connection_object,
   EipUint16 *const extended_error) {
   CipError cip_error = kCipErrorSuccess;
 

source/src/cip/cipclass3connection.h

@@ -50,7 +50,7 @@ EipStatus CipClass3ConnectionObjectStateEstablishedHandler(
  *    - On an error the general status code to be put into the response
  */
 CipError EstablishClass3Connection(
-  CipConnectionObject *RESTRICT const connection_object,
+  const CipConnectionObject *RESTRICT const connection_object,
   EipUint16 *const extended_error);
 
 /** @brief Initializes the explicit connections mechanism