Merge pull request #251 from JAndrassy/dns_ip

DNS server IP getter dnsIP()

Author: pennam

docs/api.md

@@ -1720,6 +1720,71 @@ void setup()
 void loop () {}
 ```
 
+### `WiFi.dnsIP()`
+
+#### Description
+
+Returns the DNS server IP address for the device.
+
+
+#### Syntax
+
+```
+WiFi.dnsIP()
+WiFi.dnsIP(n)
+
+```
+
+#### Parameters
+optional parameter n for the number of the DNS server to get the second DNS serverv
+
+#### Returns
+- the DNS server IP address for the device (IPAddress).
+
+#### Example
+
+```
+#include <WiFiNINA.h>
+
+#include "arduino_secrets.h"
+char ssid[] = SECRET_SSID;
+char pass[] = SECRET_PASS;
+
+IPAddress emptyIP;
+
+void setup() {
+
+  Serial.begin(115200);
+  while (!Serial) {}
+
+  Serial.print("Attempting to connect to SSID: ");
+  Serial.println(ssid);
+  int status = WiFi.begin(ssid, pass);
+  if ( status != WL_CONNECTED) {
+    Serial.println("Couldn't get a WiFi connection");
+    while(true);
+  }
+
+  Serial.print("DHCP assigned DNS server: ");
+  IPAddress dns1 = WiFi.dnsIP();
+  if (dns1 == emptyIP) {
+    Serial.println("not set");
+  } else {
+    dns1.printTo(Serial);
+    Serial.println();
+    IPAddress dns2 = WiFi.dnsIP(1);
+    if (dns2 != emptyIP) {
+      Serial.print("DNS server2: ");
+      dns2.printTo(Serial);
+      Serial.println();
+    }
+  }
+
+}
+
+void loop() {
+}
+```
 ### `WiFi.getTime()`
 
 #### Description

src/WiFi.cpp

@@ -266,6 +266,16 @@ IPAddress WiFiClass::gatewayIP()
 	return ret;
 }
 
+IPAddress WiFiClass::dnsIP(int n)
+{
+  if (n > 1)
+    return IPAddress(0,0,0,0);
+  IPAddress dnsip0;
+  IPAddress dnsip1;
+  WiFiDrv::getDNS(dnsip0, dnsip1);
+  return n ? dnsip1 : dnsip0;
+}
+
 const char* WiFiClass::SSID()
 {
     return WiFiDrv::getCurrentSSID();

src/WiFi.h

@@ -178,6 +178,14 @@ class WiFiClass
      */
    IPAddress gatewayIP();
 
+   /*
+    * Get the DNS server IP address.
+    * param n: index of the DNS server
+    * return: DNS server IP address value
+    * requires firmware version > 1.5.0
+    */
+   IPAddress dnsIP(int n = 0);
+
     /*
      * Return the current SSID associated with the network
      *

src/utility/wifi_drv.cpp

@@ -418,6 +418,39 @@ void WiFiDrv::getIpAddress(IPAddress& ip)
 	ip = _gatewayIp;
  }
 
+ void WiFiDrv::getDNS(IPAddress& dnsip0, IPAddress& dnsip1)
+ {
+   uint8_t ip0[WL_IPV4_LENGTH] = {0};
+   uint8_t ip1[WL_IPV4_LENGTH] = {0};
+
+   tParam params[PARAM_NUMS_2] = { {0, (char*)ip0}, {0, (char*)ip1}};
+
+   WAIT_FOR_SLAVE_SELECT();
+
+   // Send Command
+   SpiDrv::sendCmd(GET_DNS_CONFIG_CMD, PARAM_NUMS_1);
+
+   uint8_t _dummy = DUMMY_DATA;
+   SpiDrv::sendParam(&_dummy, sizeof(_dummy), LAST_PARAM);
+
+   // pad to multiple of 4
+   SpiDrv::readChar();
+   SpiDrv::readChar();
+
+   SpiDrv::spiSlaveDeselect();
+   //Wait the reply elaboration
+   SpiDrv::waitForSlaveReady();
+   SpiDrv::spiSlaveSelect();
+
+   // Wait for reply
+   SpiDrv::waitResponseParams(GET_DNS_CONFIG_CMD, PARAM_NUMS_2, params);
+
+   SpiDrv::spiSlaveDeselect();
+
+   dnsip0 = ip0;
+   dnsip1 = ip1;
+ }
+
 const char* WiFiDrv::getCurrentSSID()
 {
 	WAIT_FOR_SLAVE_SELECT();

src/utility/wifi_drv.h

@@ -181,6 +181,13 @@ class WiFiDrv
      */
     static void getGatewayIP(IPAddress& ip);
 
+    /*
+     * Get the DNS servers IP addresses.
+     *
+     * return: copy the DNS servers IP addresses into IPAddress objects
+     */
+    static void getDNS(IPAddress& dnsip0, IPAddress& dnsip1);
+
     /*
      * Return the current SSID associated with the network
      *

src/utility/wifi_spi.h

@@ -56,6 +56,7 @@ enum {
 	SET_AP_PASSPHRASE_CMD = 0x19,
 	SET_DEBUG_CMD		= 0x1A,
 	GET_TEMPERATURE_CMD = 0x1B,
+	GET_DNS_CONFIG_CMD = 0x1E,
 	GET_REASON_CODE_CMD = 0x1F,
 
 	GET_CONN_STATUS_CMD	= 0x20,