Fixes DNS Server Memory Leak when deleted (#6707)

Author: SuGlider

libraries/DNSServer/src/DNSServer.cpp

@@ -20,6 +20,22 @@ DNSServer::DNSServer()
   _port = 0;
 }
 
+DNSServer::~DNSServer()
+{
+  if (_dnsHeader) {
+    free(_dnsHeader);
+    _dnsHeader = NULL;
+  }
+  if (_dnsQuestion) {
+    free(_dnsQuestion);
+    _dnsQuestion = NULL;
+  }
+  if (_buffer) {
+    free(_buffer);
+    _buffer = NULL;
+  }
+}
+
 bool DNSServer::start(const uint16_t &port, const String &domainName,
                      const IPAddress &resolvedIP)
 {

libraries/DNSServer/src/DNSServer.h

@@ -76,6 +76,7 @@ class DNSServer
 {
   public:
     DNSServer();
+    ~DNSServer();
     void processNextRequest();
     void setErrorReplyCode(const DNSReplyCode &replyCode);
     void setTTL(const uint32_t &ttl);