DNSServer status getters added

add isUp() method - returns 'true' if server is up and UDP socket is listening for UDP req's
add isCaptive() method - returns 'true' if server runs in catch-all (captive portal mode)
some doxygen comments added
start() method now keeps existing IP address if any

Author: vortigont

libraries/DNSServer/src/DNSServer.cpp

@@ -19,18 +19,18 @@ DNSServer::DNSServer(const String &domainName) : _port(DNS_DEFAULT_PORT), _ttl(h
 
 
 bool DNSServer::start(){
-  if (WiFi.getMode() & WIFI_AP){
-    _resolvedIP = WiFi.softAPIP();
-  } else return false;        // won't run if WiFi is not in AP mode
+  if (_resolvedIP.operator uint32_t() == 0){    // no address is set, try to obtain AP interface's IP
+    if (WiFi.getMode() & WIFI_AP){
+      _resolvedIP = WiFi.softAPIP();
+    } else return false;              // won't run if WiFi is not in AP mode
+  } 
 
   _udp.close();
   _udp.onPacket([this](AsyncUDPPacket& pkt){ this->_handleUDP(pkt); });
   return _udp.listen(_port);
 }
 
-bool DNSServer::start(const uint16_t &port, const String &domainName,
-                     const IPAddress &resolvedIP)
-{
+bool DNSServer::start(uint16_t port, const String &domainName, const IPAddress &resolvedIP){
   _port = port;
   if (domainName != "*"){
     _domainName = domainName;

libraries/DNSServer/src/DNSServer.h

@@ -75,20 +75,50 @@ struct DNSQuestion
 class DNSServer
 {
   public:
+    /**
+     * @brief Construct a new DNSServer object
+     * by default server is configured to run in "Captive-portal" mode
+     * it must be started with start() call to establish a listening socket
+     * 
+     */
     DNSServer();
+
     /**
      * @brief Construct a new DNSServer object
      * builds DNS server with default parameters
      * @param domainName - domain name to serve
      */
     DNSServer(const String &domainName);
     ~DNSServer(){};                   // default d-tor
-    void processNextRequest(){};      // stub, left for compatibility with an old version
+
+    // Copy semantics not implemented (won't run on same UDP port anyway)
+    DNSServer(const DNSServer&) = delete;
+    DNSServer& operator=(const DNSServer&) = delete;
+
+
+    /**
+     * @brief stub, left for compatibility with an old version
+     * does nothing actually
+     * 
+     */
+    void processNextRequest(){};
+
+    /**
+     * @brief Set the Error Reply Code for all req's not matching predifined domain
+     * 
+     * @param replyCode 
+     */
     void setErrorReplyCode(const DNSReplyCode &replyCode);
+
+    /**
+     * @brief set TTL for successfull replies
+     * 
+     * @param ttl in seconds
+     */
     void setTTL(const uint32_t &ttl);
 
     /**
-     * @brief Starts a server with current configuration or with default parameters
+     * @brief (re)Starts a server with current configuration or with default parameters
      * if it's the first call.
      * Defaults are:
      * port: 53
@@ -100,13 +130,39 @@ class DNSServer
      */
     bool start();
 
-    // Returns true if successful, false if there are no sockets available
-    bool start(const uint16_t &port,
+    /**
+     * @brief (re)Starts a server with provided configuration
+     * 
+     * @return true on success
+     * @return false if IP or socket error
+     */
+    bool start(uint16_t port,
               const String &domainName,
               const IPAddress &resolvedIP);
-    // stops the DNS server
+
+    /**
+     * @brief stops the server and close UDP socket
+     * 
+     */
     void stop();
 
+    /**
+     * @brief returns true if DNS server runs in captive-portal mode
+     * i.e. all requests are served with AP's ip address
+     * 
+     * @return true if catch-all mode active
+     * @return false otherwise
+     */
+    inline bool isCaptive() const { return _domainName.isEmpty(); };
+
+    /**
+     * @brief returns 'true' if server is up and UDP socket is listening for UDP req's
+     * 
+     * @return true if server is up
+     * @return false otherwise
+     */
+    inline bool isUp() { return _udp.connected(); };
+
   private:
     AsyncUDP _udp;
     uint16_t _port;