Ethernet.setHostname added (hostname to send with DHCP request)

Author: JAndrassy

src/Dhcp.cpp

@@ -204,6 +204,7 @@ void DhcpClass::send_DHCP_MESSAGE(uint8_t messageType, uint16_t secondsElapsed)
 
     // OPT - host name
     buffer[16] = hostName;
+   if (_hostname == nullptr) {
     buffer[17] = strlen(HOST_NAME) + 6; // length of hostname + last 3 bytes of mac address
     strcpy((char*)&(buffer[18]), HOST_NAME);
 
@@ -213,6 +214,12 @@ void DhcpClass::send_DHCP_MESSAGE(uint8_t messageType, uint16_t secondsElapsed)
 
     //put data in W5100 transmit buffer
     _dhcpUdpSocket.write(buffer, 30);
+   } else {
+     uint8_t len = strlen(_hostname);
+     buffer[17] = len;
+    _dhcpUdpSocket.write(buffer, 18);
+    _dhcpUdpSocket.write(_hostname, len);
+   }
 
     if(messageType == DHCP_REQUEST)
     {
@@ -468,6 +475,10 @@ IPAddress DhcpClass::getDnsServerIp()
     return IPAddress(_dhcpDnsServerIp);
 }
 
+void DhcpClass::setHostname(const char* hostname) {
+  _hostname = hostname;
+}
+
 void DhcpClass::printByte(char * buf, uint8_t n ) {
   char *str = &buf[1];
   buf[0]='0';

src/Dhcp.h

@@ -141,6 +141,7 @@ class DhcpClass {
   uint32_t _dhcpInitialTransactionId;
   uint32_t _dhcpTransactionId;
   uint8_t  _dhcpMacAddr[6];
+  const char* _hostname = nullptr;
 #ifdef __arm__
   uint8_t  _dhcpLocalIp[4] __attribute__((aligned(4)));
   uint8_t  _dhcpSubnetMask[4] __attribute__((aligned(4)));
@@ -181,6 +182,8 @@ class DhcpClass {
 
   int beginWithDHCP(uint8_t *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
   int checkLease();
+
+  void setHostname(const char* hostname);
 };
 
 #endif

src/Ethernet.cpp

@@ -56,11 +56,21 @@ void UIPEthernetClass::init(uint8_t csPin)
 }
 
 #if UIP_UDP
+void
+UIPEthernetClass::setHostname(const char* hostname)
+{
+  if (_dhcp == NULL) {
+    _dhcp = new DhcpClass();
+  }
+  _dhcp->setHostname(hostname);
+}
+
 int
 UIPEthernetClass::begin(const uint8_t* mac, unsigned long timeout, unsigned long responseTimeout)
 {
-  static DhcpClass s_dhcp;
-  _dhcp = &s_dhcp;
+  if (_dhcp == NULL) {
+    _dhcp = new DhcpClass();
+  }
 
   // Initialise the basic info
   init(mac);

src/Ethernet.h

@@ -104,6 +104,8 @@ class UIPEthernetClass
   void setDnsServerIP(const IPAddress dns_server) { _dnsServerAddress = dns_server; }
   void setDNS(IPAddress dns_server)  { _dnsServerAddress = dns_server; }
 
+  void setHostname(const char* hostname); // only the pointer is stored!
+
   int hostByName(const char* hostname, IPAddress& result);
 
 private: