fix and move ldsMe to its own class (eclipse-4diac#239)

 * fix and move ldsMe to its own class 
 * add documentation 
 * update for v1.4.5
 * remove not needed include

src/com/opc_ua/CMakeLists.txt

@@ -91,6 +91,8 @@ if (FORTE_COM_OPC_UA)
 
     add_subdirectory(FBs)    
     add_subdirectory(types)
+    add_subdirectory(detail)
+
 
     if(FORTE_COM_OPC_UA_ENCRYPTION)
       SET(FORTE_COM_OPC_UA_ENCRYPTION_INCLUDE_DIR "" CACHE STRING "ABSOLUTE path to encryption headers")

src/com/opc_ua/detail/CMakeLists.txt

@@ -0,0 +1,4 @@
+
+if(FORTE_COM_OPC_UA_MULTICAST)
+  forte_add_sourcefile_hcpp(lds_me_handler)
+endif(FORTE_COM_OPC_UA_MULTICAST)

src/com/opc_ua/detail/lds_me_handler.cpp

@@ -0,0 +1,100 @@
+
+#include "lds_me_handler.h"
+
+#include "devlog.h"
+
+using namespace forte::com::opc_ua::detail;
+
+LdsMeHandler::LdsMeHandler(UA_Server& paUaServer) : mUaServer{paUaServer}  {
+  UA_Server_setServerOnNetworkCallback(&mUaServer, serverOnNetworkCallback, this);
+}
+
+LdsMeHandler::~LdsMeHandler() {
+  for(const auto& registeredServer : mRegisteredServers){
+    deregisterDiscoveryServer(registeredServer.mString);
+  }
+  UA_Server_setServerOnNetworkCallback(&mUaServer, nullptr, nullptr);
+}
+
+void LdsMeHandler::configureServer(UA_ServerConfig& paUaServerConfig, const std::string& paServerName) {
+  UA_String_clear(&paUaServerConfig.mdnsConfig.mdnsServerName);
+  paUaServerConfig.mdnsConfig.mdnsServerName = UA_String_fromChars(paServerName.c_str());
+  // Enable the mDNS announce and response functionality
+  paUaServerConfig.mdnsEnabled = true;
+}
+
+void LdsMeHandler::serverOnNetworkCallback(const UA_ServerOnNetwork* paServerOnNetwork, UA_Boolean paIsServerAnnounce, UA_Boolean paIsTxtReceived, void* paData) { 
+
+  if(!paIsTxtReceived) {
+    return; // we wait until the corresponding TXT record is announced.
+  }
+
+  DEVLOG_DEBUG("[OPC UA LDS ME]: mDNS %s '%.*s' with url '%.*s'\n", paIsServerAnnounce ? "announce" : "remove", paServerOnNetwork->serverName.length,
+      paServerOnNetwork->serverName.data, paServerOnNetwork->discoveryUrl.length, paServerOnNetwork->discoveryUrl.data);
+
+  // check if server is LDS
+  bool isServerLDS = false;
+
+  UA_StringRAII ldsStr("LDS");
+  for(unsigned int i = 0; i < paServerOnNetwork->serverCapabilitiesSize; i++) {
+    if(UA_String_equal(&paServerOnNetwork->serverCapabilities[i], &ldsStr.mString)) {
+      isServerLDS = true;
+      break;
+    }
+  }
+
+  // skip non-LDS servers
+  if(!isServerLDS) {
+    return;
+  }
+
+  auto handler = static_cast<LdsMeHandler*>(paData);
+
+  auto foundDiscoveryUrl = handler->mRegisteredServers.end();
+  for(auto iter = handler->mRegisteredServers.begin(); iter != handler->mRegisteredServers.end(); iter++) {
+    if(UA_String_equal(&paServerOnNetwork->discoveryUrl, &iter->mString)) {
+      foundDiscoveryUrl = iter;
+      break;
+    }
+  }
+
+  // if a new server is being announced
+  if(paIsServerAnnounce && foundDiscoveryUrl == handler->mRegisteredServers.end()) {
+    if(handler->registerDiscoveryServer(paServerOnNetwork->discoveryUrl)){
+        handler->mRegisteredServers.emplace_back(paServerOnNetwork->discoveryUrl);
+    }
+  // if a known server is being un-announced
+  } else if(!paIsServerAnnounce && foundDiscoveryUrl != handler->mRegisteredServers.end()) {
+    handler->deregisterDiscoveryServer(foundDiscoveryUrl->mString);
+    handler->mRegisteredServers.erase(foundDiscoveryUrl);
+  }
+}
+
+bool LdsMeHandler::registerDiscoveryServer(const UA_String& paDiscoveryUrl) {
+
+  UA_ClientConfig clientConfig;
+  memset(&clientConfig, 0, sizeof(UA_ClientConfig));
+  UA_ClientConfig_setDefault(&clientConfig);
+  auto retVal = UA_Server_registerDiscovery(&mUaServer, &clientConfig, paDiscoveryUrl, UA_STRING_NULL);
+  if( UA_STATUSCODE_GOOD != retVal) {
+    DEVLOG_ERROR("[OPC UA LDSME]: Could not register with LDS. Error: %s\n", UA_StatusCode_name(retVal));
+    return false;
+  }
+  DEVLOG_INFO("[OPC UA LDSME]: Registered to LDS '%.*s'\n", paDiscoveryUrl.length, paDiscoveryUrl.data);
+  return true;
+}
+
+void LdsMeHandler::deregisterDiscoveryServer(const UA_String& paDiscoveryUrl) {
+  UA_ClientConfig clientConfig;
+  memset(&clientConfig, 0, sizeof(UA_ClientConfig));
+  UA_ClientConfig_setDefault(&clientConfig);
+
+  auto retVal = UA_Server_deregisterDiscovery(&mUaServer, &clientConfig, paDiscoveryUrl);
+  // if unregister fails, we don't do anything else
+  if( UA_STATUSCODE_GOOD != retVal) {
+    DEVLOG_ERROR("[OPC UA LDSME]: Could not deregister with LDS. Error: %s\n", UA_StatusCode_name(retVal));
+    return;
+  }
+
+  DEVLOG_INFO("[OPC UA LDSME]: Unregistered from LDS '%.*s'\n", paDiscoveryUrl.length, paDiscoveryUrl.data);
+}

src/com/opc_ua/detail/lds_me_handler.h

@@ -0,0 +1,101 @@
+/*******************************************************************************
+ * Copyright (c) 2024 Jose Cabral
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *    Jose Cabral
+ *      - initial integration of the OPC-UA protocol
+ *******************************************************************************/
+
+#ifndef SRC_COM_OPC_UA_DETAIL_LDSMEHANDLER_H_
+#define SRC_COM_OPC_UA_DETAIL_LDSMEHANDLER_H_
+
+#include <open62541.h>
+
+#include <string>
+#include <vector>
+
+namespace forte::com::opc_ua::detail {
+
+/**
+ * @brief Handles all things related to LDS-ME
+ * 
+ * Configures the server to accept LDS-ME messages and handles them accordingly.
+ */
+class LdsMeHandler {
+  public:
+
+    /**
+     * @brief Register this instance as handler for incoming discovery message
+     * 
+     * @param paUaServer OpcUa server to handle
+     */
+    LdsMeHandler(UA_Server& paUaServer);
+
+    /**
+     * @brief Un-register this instance as handler incoming discovery message
+     * 
+     */
+    ~LdsMeHandler();
+
+
+    /**
+     * @brief Sets the proper values to the server configuration so it accepts LDS-ME messages
+     * 
+     * @param paUaServerConfig configuration to be set
+     * @param paServerName server name to be used when registering to the discovery server 
+     */
+    static void configureServer(UA_ServerConfig& paUaServerConfig, const std::string& paServerName);
+
+  private:
+
+    bool registerDiscoveryServer(const UA_String& paDiscoveryUrl);
+    void deregisterDiscoveryServer(const UA_String& paDiscoveryUrl);
+
+    static void serverOnNetworkCallback(const UA_ServerOnNetwork* paServerOnNetwork, UA_Boolean paIsServerAnnounce, UA_Boolean paIsTxtReceived, void* paData);
+
+    UA_Server& mUaServer;
+
+    // Handle the lifetime of a UA_String nicely
+    class UA_StringRAII {
+      public:
+        UA_StringRAII(const UA_String& paString) {
+          UA_String_copy(&paString, &mString);
+        }
+
+        UA_StringRAII(const char* paString) {
+          mString = UA_String_fromChars(paString);
+        }
+
+        ~UA_StringRAII() {
+          UA_String_clear(&mString);
+        }
+
+        UA_StringRAII(UA_StringRAII&& paOther) {
+          *this = std::move(paOther);
+        }
+
+        UA_StringRAII& operator=(UA_StringRAII&& paOther) {
+          mString = paOther.mString;
+          UA_String_init(&paOther.mString);  
+          return *this; 
+        };
+
+
+        UA_StringRAII(const UA_StringRAII&) = delete;
+        UA_StringRAII& operator=(const UA_StringRAII&) = delete;
+
+        UA_String mString;
+    };
+
+    /// List of discovery servers where this instance is already registered
+    std::vector<UA_StringRAII> mRegisteredServers;
+};
+}
+
+#endif // SRC_COM_OPC_UA_DETAIL_LDSMEHANDLER_H_

src/com/opc_ua/opcua_local_handler.cpp

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2015, 2023 Florian Froschermeier <[email protected]>,
+ * Copyright (c) 2015, 2024 Florian Froschermeier <[email protected]>,
  *                          fortiss GmbH, Primetals Technologies Austria GmbH
  *
  * This program and the accompanying materials are made available under the
@@ -30,6 +30,9 @@
 #include "forte_printer.h"
 #include "../../arch/utils/mainparam_utils.h"
 #include "opcua_local_handler.h"
+#ifdef FORTE_COM_OPC_UA_MULTICAST
+#include "detail/lds_me_handler.h"
+#endif //FORTE_COM_OPC_UA_MULTICAST
 #include <string>
 
 #ifndef FORTE_COM_OPC_UA_CUSTOM_HOSTNAME
@@ -57,12 +60,6 @@ COPC_UA_Local_Handler::~COPC_UA_Local_Handler() {
     UA_NodeId_delete(const_cast<UA_NodeId*>(iter->mNodeId));
   }
   mNodesReferences.clear();
-
-#ifdef FORTE_COM_OPC_UA_MULTICAST
-  for(CSinglyLinkedList<UA_String*>::Iterator iter = mRegisteredWithLds.begin(); iter != mRegisteredWithLds.end(); ++iter) {
-    UA_String_delete(*iter);
-  }
-#endif //FORTE_COM_OPC_UA_MULTICAST
 }
 
 void COPC_UA_Local_Handler::enableHandler() {
@@ -91,12 +88,15 @@ void COPC_UA_Local_Handler::run() {
     configureUAServer(serverStrings, *uaServerConfig);
 
     if(initializeNodesets(*mUaServer)) {
-#ifdef FORTE_COM_OPC_UA_MULTICAST
-      UA_Server_setServerOnNetworkCallback(mUaServer, serverOnNetworkCallback, this);
-#endif //FORTE_COM_OPC_UA_MULTICAST
-
       UA_StatusCode retVal = UA_Server_run_startup(mUaServer);
       if(UA_STATUSCODE_GOOD == retVal) {
+        {
+#ifdef FORTE_COM_OPC_UA_MULTICAST
+          // the extra curly brace on top is to limit the lifetime of this object. 
+          // it was avoided to have inside this ifdef to also avoid the closing brace
+          // with the exta ifdef making it cleaner this way
+          auto mLdsMeHandler = forte::com::opc_ua::detail::LdsMeHandler(*mUaServer);
+#endif //FORTE_COM_OPC_UA_MULTICAST
         mServerStarted.inc();
         while(isAlive()) {
           UA_UInt16 timeToSleepMs;
@@ -110,6 +110,7 @@ void COPC_UA_Local_Handler::run() {
 
           mServerNeedsIteration.timedWait(static_cast<TForteUInt64>(timeToSleepMs) * 1000000ULL);
         }
+        }
         retVal = UA_Server_run_shutdown(mUaServer);
         if(UA_STATUSCODE_GOOD == retVal) {
           DEVLOG_INFO("[OPC UA LOCAL]: Server successfully stopped\n");
@@ -166,10 +167,7 @@ void COPC_UA_Local_Handler::generateServerStrings(TForteUInt16 paUAServerPort, U
 
 void COPC_UA_Local_Handler::configureUAServer(UA_ServerStrings &paServerStrings, UA_ServerConfig &paUaServerConfig) const {
 #ifdef FORTE_COM_OPC_UA_MULTICAST
-  paUaServerConfig.applicationDescription.applicationType = UA_APPLICATIONTYPE_DISCOVERYSERVER;
-  // hostname will be added by mdns library
-  UA_String_clear(&paUaServerConfig.mdnsConfig.mdnsServerName);
-  paUaServerConfig.mdnsConfig.mdnsServerName = UA_String_fromChars(paServerStrings.mMdnsServerName.c_str());
+  forte::com::opc_ua::detail::LdsMeHandler::configureServer(paUaServerConfig, paServerStrings.mMdnsServerName);
 #endif //FORTE_COM_OPC_UA_MULTICAST
 
   UA_Array_delete(paUaServerConfig.serverUrls, paUaServerConfig.serverUrlsSize, &UA_TYPES[UA_TYPES_STRING]);
@@ -280,85 +278,7 @@ void COPC_UA_Local_Handler::getNodesReferencedByAction(const CActionInfo &paActi
   }
 }
 
-#ifdef FORTE_COM_OPC_UA_MULTICAST
-
-const UA_String* COPC_UA_Local_Handler::getDiscoveryUrl() const {
-
-  UA_ServerConfig *mServerConfig = UA_Server_getConfig(mUaServer); //change mServerConfig to serverConfig when only master branch is present
-  if(0 == mServerConfig->networkLayersSize) {
-    return 0;
-  }
-  return &mServerConfig->networkLayers[0].discoveryUrl;
-}
-
-void COPC_UA_Local_Handler::serverOnNetworkCallback(const UA_ServerOnNetwork *paServerOnNetwork, UA_Boolean paIsServerAnnounce, UA_Boolean paIsTxtReceived,
-    void *paData) { //NOSONAR
-  COPC_UA_Local_Handler *handler = static_cast<COPC_UA_Local_Handler*>(paData);
-
-  const UA_String *ownDiscoverUrl = handler->getDiscoveryUrl();
-
-  if(!ownDiscoverUrl || UA_String_equal(&paServerOnNetwork->discoveryUrl, ownDiscoverUrl)) {
-    // skip self
-    return;
-  }
-
-  if(!paIsTxtReceived) {
-    return; // we wait until the corresponding TXT record is announced.
-  }
-
-  DEVLOG_DEBUG("[OPC UA LOCAL]: mDNS %s '%.*s' with url '%.*s'\n", paIsServerAnnounce ? "announce" : "remove", paServerOnNetwork->serverName.length,
-      paServerOnNetwork->serverName.data, paServerOnNetwork->discoveryUrl.length, paServerOnNetwork->discoveryUrl.data);
-
-  // check if server is LDS, and then register
-  UA_String ldsStr = UA_String_fromChars("LDS");
-  for(unsigned int i = 0; i < paServerOnNetwork->serverCapabilitiesSize; i++) {
-    if(UA_String_equal(&paServerOnNetwork->serverCapabilities[i], &ldsStr)) {
-      if(paIsServerAnnounce) {
-        handler->registerWithLds(&paServerOnNetwork->discoveryUrl);
-      } else {
-        handler->removeLdsRegister(&paServerOnNetwork->discoveryUrl);
-      }
-      break;
-    }
-  }
-  UA_String_clear(&ldsStr);
-}
-
-void COPC_UA_Local_Handler::registerWithLds(const UA_String *paDiscoveryUrl) {
-  // check if already registered with the given LDS
-  for(CSinglyLinkedList<UA_String*>::Iterator iter = mRegisteredWithLds.begin(); iter != mRegisteredWithLds.end(); ++iter) {
-    if(UA_String_equal(paDiscoveryUrl, *iter)) {
-      return;
-    }
-  }
 
-  // will be freed when removed from list
-  UA_String *discoveryUrlChar = 0;
-  UA_String_copy(paDiscoveryUrl, discoveryUrlChar);
-
-  mRegisteredWithLds.pushFront(discoveryUrlChar);
-  DEVLOG_INFO("[OPC UA LOCAL]: Registering with LDS '%.*s'\n", paDiscoveryUrl->length, paDiscoveryUrl->data);
-  UA_StatusCode retVal = UA_Server_addPeriodicServerRegisterCallback(mUaServer, 0, reinterpret_cast<const char*>(discoveryUrlChar->data), 10 * 60 * 1000, 500, 0);
-  if( UA_STATUSCODE_GOOD != retVal) {
-    DEVLOG_ERROR("[OPC UA LOCAL]: Could not register with LDS. Error: %s\n", UA_StatusCode_name(retVal));
-  }
-}
-
-void COPC_UA_Local_Handler::removeLdsRegister(const UA_String *paDiscoveryUrl) {
-  UA_String *toDelete = 0;
-  for(CSinglyLinkedList<UA_String*>::Iterator iter = mRegisteredWithLds.begin(); iter != mRegisteredWithLds.end(); ++iter) {
-    if(UA_String_equal(paDiscoveryUrl, *iter)) {
-      toDelete = *iter;
-      break;
-    }
-  }
-  if(toDelete) {
-    mRegisteredWithLds.erase(toDelete);
-    UA_String_delete(toDelete);
-  }
-}
-
-#endif //FORTE_COM_OPC_UA_MULTICAST
 
 UA_StatusCode COPC_UA_Local_Handler::initializeAction(CActionInfo &paActionInfo) {
   enableHandler();

src/com/opc_ua/opcua_local_handler.h

@@ -694,23 +694,6 @@ class COPC_UA_Local_Handler : public COPC_UA_HandlerAbstract, public CThread {
      * Default description for variable nodes
      */
     static const char *const mDefaultDescriptionForVariableNodes;
-
-#ifdef FORTE_COM_OPC_UA_MULTICAST
-# ifndef UA_ENABLE_DISCOVERY_MULTICAST
-#  error open62541 needs to be built with UA_ENABLE_DISCOVERY=ON and UA_ENABLE_DISCOVERY_MULTICAST=ON
-# else // UA_ENABLE_DISCOVERY_MULTICAST
-    /**
-     * List of LDS servers where this instance is already registered.
-     */
-    CSinglyLinkedList<UA_String*> mRegisteredWithLds;
-
-    const UA_String* getDiscoveryUrl() const;
-    void registerWithLds(const UA_String *paDiscoveryUrl);
-    void removeLdsRegister(const UA_String *paDiscoveryUrl);
-    static void serverOnNetworkCallback(const UA_ServerOnNetwork *paServerOnNetwork, UA_Boolean paIsServerAnnounce, UA_Boolean paIsTxtReceived, void *paData);
-# endif //UA_ENABLE_DISCOVERY_MULTICAST
-#endif //FORTE_COM_OPC_UA_MULTICAST
-
 };
 
 #endif /* SRC_MODULES_OPC_UA_OPCUALOCALHANDLER_H_ */