added ability to set/get hostname

Dhcp.cpp

@@ -8,6 +8,11 @@
 #include "utility/util.h"
 
 int DhcpClass::beginWithDHCP(uint8_t *mac, unsigned long timeout, unsigned long responseTimeout)
+{
+    return beginWithDHCP(mac, NULL, timeout, responseTimeout);
+}
+
+int DhcpClass::beginWithDHCP(uint8_t *mac, const char *hostname, unsigned long timeout, unsigned long responseTimeout)
 {
     _dhcpLeaseTime=0;
     _dhcpT1=0;
@@ -20,6 +25,20 @@ int DhcpClass::beginWithDHCP(uint8_t *mac, unsigned long timeout, unsigned long
     memset(_dhcpMacAddr, 0, 6); 
     reset_DHCP_lease();
 
+    if (NULL == hostname)
+    {
+      strcpy(_dhcpHostname, HOST_NAME);
+      int offset = strlen(HOST_NAME);
+      printByte((char*)&(_dhcpHostname[offset + 0]), mac[3]);
+      printByte((char*)&(_dhcpHostname[offset + 2]), mac[4]);
+      printByte((char*)&(_dhcpHostname[offset + 4]), mac[5]);
+      _dhcpHostname[offset + 6] = 0;
+    }
+    else
+    {
+      strlcpy(_dhcpHostname, hostname, MAX_HOST_NAME_LENGTH + 1);
+    }
+
     memcpy((void*)_dhcpMacAddr, (void*)mac, 6);
     _dhcp_state = STATE_DHCP_START;
     return request_DHCP_lease();
@@ -202,12 +221,8 @@ void DhcpClass::send_DHCP_MESSAGE(uint8_t messageType, uint16_t secondsElapsed)
 
     // OPT - host name
     buffer[16] = hostName;
-    buffer[17] = strlen(HOST_NAME) + 6; // length of hostname + last 3 bytes of mac address
-    strcpy((char*)&(buffer[18]), HOST_NAME);
-
-    printByte((char*)&(buffer[24]), _dhcpMacAddr[3]);
-    printByte((char*)&(buffer[26]), _dhcpMacAddr[4]);
-    printByte((char*)&(buffer[28]), _dhcpMacAddr[5]);
+    buffer[17] = strlen(_dhcpHostname); // length of hostname
+    strcpy((char*)&(buffer[18]), _dhcpHostname);
 
     //put data in W5100 transmit buffer
     _dhcpUdpSocket.write(buffer, 30);
@@ -466,6 +481,11 @@ IPAddress DhcpClass::getDnsServerIp()
     return IPAddress(_dhcpDnsServerIp);
 }
 
+const char* DhcpClass::getHostname() const
+{
+    return _dhcpHostname;
+}
+
 void DhcpClass::printByte(char * buf, uint8_t n ) {
   char *str = &buf[1];
   buf[0]='0';

Dhcp.h

@@ -44,8 +44,9 @@
 #define MAGIC_COOKIE		0x63825363
 #define MAX_DHCP_OPT	16
 
-#define HOST_NAME "ENC28J"
-#define DEFAULT_LEASE	(900) //default lease time in seconds
+#define HOST_NAME 		"ENC28J" //default host name
+#define MAX_HOST_NAME_LENGTH	12
+#define DEFAULT_LEASE		(900) //default lease time in seconds
 
 #define DHCP_CHECK_NONE         (0)
 #define DHCP_CHECK_RENEW_FAIL   (1)
@@ -156,6 +157,7 @@ class DhcpClass {
   unsigned long _secTimeout;
   uint8_t _dhcp_state;
   UIPUDP _dhcpUdpSocket;
+  char _dhcpHostname[MAX_HOST_NAME_LENGTH + 1];
 
   int request_DHCP_lease();
   void reset_DHCP_lease();
@@ -170,8 +172,10 @@ class DhcpClass {
   IPAddress getGatewayIp();
   IPAddress getDhcpServerIp();
   IPAddress getDnsServerIp();
+  const char* getHostname() const;
 
   int beginWithDHCP(uint8_t *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
+  int beginWithDHCP(uint8_t *, const char *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
   int checkLease();
 };
 

UIPEthernet.cpp

@@ -57,6 +57,11 @@ UIPEthernetClass::UIPEthernetClass()
 #if UIP_UDP
 int
 UIPEthernetClass::begin(const uint8_t* mac)
+{
+  return begin(mac, NULL);
+}
+
+UIPEthernetClass::begin(const uint8_t* mac, const char* hostname)
 {
   static DhcpClass s_dhcp;
   _dhcp = &s_dhcp;
@@ -65,7 +70,7 @@ UIPEthernetClass::begin(const uint8_t* mac)
   init(mac);
 
   // Now try to get our config info from a DHCP server
-  int ret = _dhcp->beginWithDHCP((uint8_t*)mac);
+  int ret = _dhcp->beginWithDHCP((uint8_t*)mac, hostname);
   if(ret == 1)
   {
     // We've successfully found a DHCP server and got our configuration info, so set things
@@ -160,6 +165,11 @@ IPAddress UIPEthernetClass::dnsServerIP()
   return _dnsServerAddress;
 }
 
+const char* UIPEthernetClass::hostname() const
+{
+  return _dhcp ? _dhcp->getHostname() : "";
+}
+
 void
 UIPEthernetClass::tick()
 {

UIPEthernet.h

@@ -66,6 +66,7 @@ class UIPEthernetClass
   UIPEthernetClass();
 
   int begin(const uint8_t* mac);
+  int begin(const uint8_t* mac, const char* hostname);
   void begin(const uint8_t* mac, IPAddress ip);
   void begin(const uint8_t* mac, IPAddress ip, IPAddress dns);
   void begin(const uint8_t* mac, IPAddress ip, IPAddress dns, IPAddress gateway);
@@ -80,6 +81,7 @@ class UIPEthernetClass
   IPAddress subnetMask();
   IPAddress gatewayIP();
   IPAddress dnsServerIP();
+  const char* hostname() const;
 
 private:
   static memhandle in_packet;

examples/DhcpHostname/DhcpHostname.ino

@@ -0,0 +1,46 @@
+/*
+  DHCP-based hostname printer
+
+  Circuit:
+   Ethernet shield attached to pins 10, 11, 12, 13
+
+  created 10 Dec 2016
+  by mykh
+*/
+
+#include <UIPEthernet.h>
+
+// MAC address
+byte mac[] = {
+  0x00, 0xAA, 0xBB, 0xCC, 0xDE, 0x02
+};
+// Hostname
+const char* hostname = "myarduino";
+
+// Initialize the Ethernet client library
+EthernetClient client;
+
+void setup() {
+  // Open serial communications and wait for port to open:
+  Serial.begin(9600);
+  // this check is only needed on the Leonardo:
+  while (!Serial) {
+    ;
+  }
+
+  // start the Ethernet connection:
+  Serial.println("Setup...");
+  while (Ethernet.begin(mac, hostname) == 0) {
+    Serial.println("Failed to configure Ethernet using DHCP");
+    delay(10000);
+    Serial.println("Reconnecting...");
+  }
+
+  // print your hostname:
+  Serial.print("My Hostname: ");
+  Serial.println(Ethernet.hostname());
+}
+
+void loop() {
+  Ethernet.maintain();
+}