adds support for reading option code 15 of DHCP -> domain name

Author: dmorina

src/Dhcp.cpp

@@ -331,14 +331,20 @@ uint8_t DhcpClass::parseDHCPResponse(unsigned long responseTimeout, uint32_t& tr
                     break;
 
                 case dns :
-                    
 					opt_len = _dhcpUdpSocket.read();
                     _dhcpUdpSocket.read(_dhcpDnsServerIp, 4);
                     for (int i = 0; i < opt_len-4; i++)
                     {
                         _dhcpUdpSocket.read();
                     }
                     break;
+                    
+                case domainName:
+                    opt_len = _dhcpUdpSocket.read();
+                    _dhcpDnsdomainName = (char*)malloc(sizeof(char)*opt_len+1);
+                    _dhcpUdpSocket.read(_dhcpDnsdomainName, opt_len);
+                    _dhcpDnsdomainName[opt_len] = '\0';
+                    break;
 
                 case dhcpServerIdentifier :
 
@@ -485,6 +491,11 @@ IPAddress DhcpClass::getDnsServerIp()
     return IPAddress(_dhcpDnsServerIp);
 }
 
+char* DhcpClass::getDnsDomainName()
+{
+    return _dhcpDnsdomainName;
+}
+
 void DhcpClass::printByte(char * buf, uint8_t n ) {
   char *str = &buf[1];
   buf[0]='0';

src/Dhcp.h

@@ -143,6 +143,7 @@ class DhcpClass {
   uint32_t _dhcpTransactionId;
   uint8_t  _dhcpMacAddr[6];
   uint8_t  _dhcpLocalIp[4];
+  char* _dhcpDnsdomainName;
   uint8_t  _dhcpSubnetMask[4];
   uint8_t  _dhcpGatewayIp[4];
   uint8_t  _dhcpDhcpServerIp[4];
@@ -170,6 +171,7 @@ class DhcpClass {
   IPAddress getGatewayIp();
   IPAddress getDhcpServerIp();
   IPAddress getDnsServerIp();
+  char* getDnsDomainName();
 
   int beginWithDHCP(uint8_t *, unsigned long timeout = 60000, unsigned long responseTimeout = 5000);  
   int checkLease();

src/Ethernet2.cpp

@@ -41,6 +41,7 @@ int EthernetClass::begin(void)
     w5500.setGatewayIp(_dhcp->getGatewayIp().raw_address());
     w5500.setSubnetMask(_dhcp->getSubnetMask().raw_address());
     _dnsServerAddress = _dhcp->getDnsServerIp();
+    _dnsDomainName = _dhcp->getDnsDomainName();
   }
 
   return ret;
@@ -100,6 +101,7 @@ int EthernetClass::begin(uint8_t *mac_address)
     w5500.setGatewayIp(_dhcp->getGatewayIp().raw_address());
     w5500.setSubnetMask(_dhcp->getSubnetMask().raw_address());
     _dnsServerAddress = _dhcp->getDnsServerIp();
+    _dnsDomainName = _dhcp->getDnsDomainName();
   }
 
   return ret;
@@ -157,6 +159,7 @@ int EthernetClass::maintain(){
         w5500.setGatewayIp(_dhcp->getGatewayIp().raw_address());
         w5500.setSubnetMask(_dhcp->getSubnetMask().raw_address());
         _dnsServerAddress = _dhcp->getDnsServerIp();
+        _dnsDomainName = _dhcp->getDnsDomainName();
         break;
       default:
         //this is actually a error, it will retry though
@@ -192,4 +195,8 @@ IPAddress EthernetClass::dnsServerIP()
   return _dnsServerAddress;
 }
 
+char* EthernetClass::dnsDomainName(){
+    return _dnsDomainName;
+}
+
 EthernetClass Ethernet;

src/Ethernet2.h

@@ -22,6 +22,7 @@
 class EthernetClass {
 private:
   IPAddress _dnsServerAddress;
+  char* _dnsDomainName;
   DhcpClass* _dhcp;
 public:
   uint8_t w5500_cspin;
@@ -60,6 +61,7 @@ class EthernetClass {
   IPAddress subnetMask();
   IPAddress gatewayIP();
   IPAddress dnsServerIP();
+  char* dnsDomainName();
 
   friend class EthernetClient;
   friend class EthernetServer;