public void SendDHCPMessage(DHCPMessageType messageType, DHCPTransaction transaction)
{
//mac announced itself, established IP etc....
//send the offer to the mac
byte[] subnet;
byte[] hostId;
byte[] dataToSend;
//we shall leave everything as is structure wise
//shall CHANGE the type to OFFER
//shall set the client's IP-Address
try
{
//change message type to reply
transaction.Message.D_op = 2;
//subnet
subnet = transaction.Data.SubMask.GetAddressBytes();
//create your ip address
transaction.Message.D_yiaddr = transaction.Data.IPAddr.GetAddressBytes();
//Host ID
hostId = System.Text.Encoding.ASCII.GetBytes(transaction.Data.ServerName);
CreateOptionStruct(ref transaction, messageType);
//send the data to the unit
dataToSend = BuildDataStructure(transaction.Message);
udp.SendData(dataToSend);
}
catch (Exception)
{
// TODO: handle exception
// Console.WriteLine(ex.Message);
}
finally
{
subnet = null;
//LeaseTime= null;
hostId = null;
dataToSend = null;
}
}
private void DHCPRequest(DHCPTransaction transaction, string macId)
{
//announced so then send the offer
transaction.Data.IPAddr = GetIpForDevice(macId);
transaction.Data.SubMask = IPAddress.Parse("255.255.255.0");
transaction.Data.LeaseTime = 2000;
transaction.Data.ServerName = "HASystem";
transaction.Data.MyIP = adapterIp;
transaction.Data.RouterIP = IPAddress.None;
transaction.Data.LogServerIP = "0.0.0.0";
transaction.Data.DomainIP = IPAddress.None;
dhcpServer.SendDHCPMessage(DHCPMessageType.DHCPACK, transaction);
}
private void DHCPAnnounced(DHCPTransaction transaction, string macId)
{
//options should be filled with valid data
transaction.Data.IPAddr = GetIpForDevice(macId);
transaction.Data.SubMask = IPAddress.Parse("255.255.255.0");
transaction.Data.LeaseTime = 2000;
transaction.Data.ServerName = "HASystem";
transaction.Data.MyIP = adapterIp;
transaction.Data.RouterIP = IPAddress.None;
transaction.Data.LogServerIP = "0.0.0.0";
transaction.Data.DomainIP = IPAddress.None;
dhcpServer.SendDHCPMessage(DHCPMessageType.DHCPOFFER, transaction);
}
private void UDPDataReceived(byte[] data, IPEndPoint endPoint)
{
DHCPTransaction transaction;
DHCPMessageType messageType;
string macId;
try
{
transaction = new DHCPTransaction(data);
//data is now in the structure, get the msg type
messageType = GetMessageType(transaction);
macId = ByteToString(transaction.Message.D_chaddr, transaction.Message.D_hlen);
switch (messageType)
{
case DHCPMessageType.DHCPDISCOVER:
// a Mac has requested an IP
// discover Msg Has been sent
Announced(transaction, macId);
break;
case DHCPMessageType.DHCPREQUEST:
Request(transaction, macId);
break;
}
}
catch (Exception)
{
// TODO: handle exception
// Console.WriteLine(ex.Message);
}
}
private byte[] GetOptionData(DHCPOption type, DHCPTransaction transaction)
{
// Pass the option type that you require
// Parse the option data
// Return the data in a byte of what we need
int id = 0;
byte dataId = 0;
byte dataLength = 0;
byte[] dataDump;
try
{
id = (int)type;
//loop through look for the bit that states that the identifier is there
for (int i = 0; i < transaction.Message.D_options.Length; i++)
{
//at the start we have the code + length
//i has the code, i+1 = length of data, i+1+n = data skip
dataId = transaction.Message.D_options[i];
if (dataId == id)
{
dataLength = transaction.Message.D_options[i + 1];
dataDump = new byte[dataLength];
Array.Copy(transaction.Message.D_options, i + 2, dataDump, 0, dataLength);
return dataDump;
}
else
{
// Length of code
dataLength = transaction.Message.D_options[i + 1];
i += 1 + dataLength;
}
}
}
catch (Exception)
{
// TODO: handle exception
// Console.WriteLine(ex.Message);
}
finally
{
dataDump = null;
}
return null;
}
private DHCPMessageType GetMessageType(DHCPTransaction transaction)
{
// Get the Message type, located in the options stream
byte[] data;
try
{
data = GetOptionData(DHCPOption.DHCPMessageTYPE, transaction);
if (data != null)
{
return (DHCPMessageType)data[0];
}
}
catch (Exception)
{
// TODO: handle exception
// Console.WriteLine(ex.Message);
}
return 0;
}
private void CreateOptionStruct(ref DHCPTransaction transaction, DHCPMessageType optionReplayMessage)
{
byte[] parameterRequestList;
byte[] ipAddress;
byte[] leaseTime;
byte[] serverIp;
try
{
//we look for the parameter request list
parameterRequestList = GetOptionData(DHCPOption.ParameterRequestList, transaction);
//erase the options array, and set the message type to ack
transaction.Message.D_options = null;
CreateOptionElement(DHCPOption.DHCPMessageTYPE, new byte[] { (byte)optionReplayMessage }, ref transaction.Message.D_options);
//server identifier, my IP
serverIp = transaction.Data.MyIP.GetAddressBytes();
CreateOptionElement(DHCPOption.ServerIdentifier, serverIp, ref transaction.Message.D_options);
// parameterRequestList contains the option data in a byte that is requested by the unit
foreach (byte i in parameterRequestList)
{
ipAddress = null;
switch ((DHCPOption)i)
{
case DHCPOption.SubnetMask:
ipAddress = transaction.Data.SubMask.GetAddressBytes();
break;
case DHCPOption.Router:
ipAddress = transaction.Data.RouterIP.GetAddressBytes();
break;
case DHCPOption.DomainNameServer:
ipAddress = transaction.Data.DomainIP.GetAddressBytes();
break;
case DHCPOption.DomainName:
ipAddress = System.Text.Encoding.ASCII.GetBytes(transaction.Data.ServerName);
break;
case DHCPOption.ServerIdentifier:
ipAddress = transaction.Data.MyIP.GetAddressBytes();
break;
case DHCPOption.LogServer:
ipAddress = System.Text.Encoding.ASCII.GetBytes(transaction.Data.LogServerIP);
break;
case DHCPOption.NetBIOSoverTCPIPNameServer:
break;
}
if (ipAddress != null)
{
CreateOptionElement((DHCPOption)i, ipAddress, ref transaction.Message.D_options);
}
}
//lease time
leaseTime = new byte[4];
leaseTime[3] = (byte)(transaction.Data.LeaseTime);
leaseTime[2] = (byte)(transaction.Data.LeaseTime >> 8);
leaseTime[1] = (byte)(transaction.Data.LeaseTime >> 16);
leaseTime[0] = (byte)(transaction.Data.LeaseTime >> 24);
CreateOptionElement(DHCPOption.IPAddressLeaseTime, leaseTime, ref transaction.Message.D_options);
CreateOptionElement(DHCPOption.RenewalTimeValue_T1, leaseTime, ref transaction.Message.D_options);
CreateOptionElement(DHCPOption.RebindingTimeValue_T2, leaseTime, ref transaction.Message.D_options);
//create the end option
Array.Resize(ref transaction.Message.D_options, transaction.Message.D_options.Length + 1);
Array.Copy(new byte[] { 255 }, 0, transaction.Message.D_options, transaction.Message.D_options.Length - 1, 1);
}
catch (Exception)
{
// TODO: handle exception
// Console.WriteLine(ex.Message);
}
finally
{
leaseTime = null;
parameterRequestList = null;
ipAddress = null;
}
}
