From 294063ec3e8fa4eee6499310bc7e20903cdd730d Mon Sep 17 00:00:00 2001
From: Juraj Andrassy <juraj.andrassy@gmail.com>
Date: Sat, 7 Oct 2023 13:41:11 +0200
Subject: [PATCH] Ethernet.setHostname added (hostname to send with DHCP
 request)

---
 src/Dhcp.cpp     | 13 +++++++++++++
 src/Ethernet.cpp | 13 +++++++++++--
 src/Ethernet.h   |  3 +++
 3 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/Dhcp.cpp b/src/Dhcp.cpp
index 2bfd584b..58763ae7 100644
--- a/src/Dhcp.cpp
+++ b/src/Dhcp.cpp
@@ -188,6 +188,8 @@ 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);
 
@@ -197,6 +199,12 @@ 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) {
 		buffer[0] = dhcpRequestedIPaddr;
@@ -420,6 +428,11 @@ 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];
diff --git a/src/Ethernet.cpp b/src/Ethernet.cpp
index 8d9ce7fd..2cc7181a 100644
--- a/src/Ethernet.cpp
+++ b/src/Ethernet.cpp
@@ -28,8 +28,9 @@ DhcpClass* EthernetClass::_dhcp = NULL;
 
 int EthernetClass::begin(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
 	if (W5100.init() == 0) return 0;
@@ -178,6 +179,14 @@ IPAddress EthernetClass::gatewayIP()
 	return ret;
 }
 
+void EthernetClass::setHostname(const char* hostname)
+{
+	if (_dhcp == NULL) {
+		_dhcp = new DhcpClass();
+	}
+	_dhcp->setHostname(hostname);
+}
+
 void EthernetClass::setMACAddress(const uint8_t *mac_address)
 {
 	SPI.beginTransaction(SPI_ETHERNET_SETTINGS);
diff --git a/src/Ethernet.h b/src/Ethernet.h
index 0045de88..7375c07d 100644
--- a/src/Ethernet.h
+++ b/src/Ethernet.h
@@ -97,6 +97,7 @@ class EthernetClass {
 	static IPAddress gatewayIP();
 	static IPAddress dnsServerIP() { return _dnsServerAddress; }
 
+	void setHostname(const char* hostname); // only the pointer is stored!
 	void setMACAddress(const uint8_t *mac_address);
 	void setLocalIP(const IPAddress local_ip);
 	void setSubnetMask(const IPAddress subnet);
@@ -275,6 +276,7 @@ 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)));
@@ -314,6 +316,7 @@ class DhcpClass {
 
 	int beginWithDHCP(uint8_t *, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
 	int checkLease();
+	void setHostname(const char* hostname);
 };