Add ::dnsServerIP

Author: manchoz

libraries/SocketWrapper/src/SocketHelpers.cpp

@@ -43,6 +43,13 @@ arduino::IPAddress arduino::MbedSocketClass::gatewayIP() {
  return ipAddressFromSocketAddress(ip);
 }
 
+arduino::IPAddress arduino::MbedSocketClass::dnsServerIP() {
+ SocketAddress ip;
+ NetworkInterface* interface = getNetwork();
+ interface->get_dns_server(0, &ip, nullptr);
+ return ipAddressFromSocketAddress(ip);
+}
+
 void arduino::MbedSocketClass::config(arduino::IPAddress local_ip) {
  nsapi_addr_t convertedIP = { NSAPI_IPv4, { local_ip[0], local_ip[1], local_ip[2], local_ip[3] } };
  _ip = SocketAddress(convertedIP);

libraries/SocketWrapper/src/SocketHelpers.h

@@ -92,6 +92,13 @@ class MbedSocketClass {
  */
  IPAddress gatewayIP();
 
+ /*
+ * Get the DNS Server ip address.
+ *
+ * return: DNS Server ip address value
+ */
+ IPAddress dnsServerIP();
+
  virtual NetworkInterface* getNetwork() = 0;
 
  int download(char* url, const char* target, bool const is_https = false);
@@ -128,4 +135,4 @@ using SocketHelpers = MbedSocketClass;
 
 }
 
-#endif
+#endif