private void Respond(DhcpFormat request, DhcpFormat.MessageType m)
{
DhcpFormat response = new DhcpFormat(m);
response.TransactionID = request.TransactionID;
EthernetAddress hwAddress = request.GetHardwareAddress();
response.SetHardwareAddress(hwAddress);
switch (m)
{
case DhcpFormat.MessageType.Offer:
response.NextServerIPAddress = ServerAddress;
response.AddOption(
DhcpIPAddressLeaseTime.Create(RebindingTime)
);
goto case DhcpFormat.MessageType.Ack;
case DhcpFormat.MessageType.Ack:
response.YourIPAddress = HostAddress;
assignedAddress = HostAddress;
FillOptions(request, response);
break;
case DhcpFormat.MessageType.Nak:
// Nothing to do
break;
default:
return;
}
SendResponsePacket(response);
}
public void Receive(NetPacket packet)
{
packet.Reset();
Console.WriteLine("Received {0} bytes", packet.Length);
if (ValidHeaders(packet) == false)
{
SetState(ServerState.Failed);
return;
}
try {
DhcpFormat dhcp = DhcpFormat.Parse(packet);
SortedList options = dhcp.GetOptions();
DhcpByteOption message = options[DhcpMessageType.OptionCode]
as DhcpByteOption;
if (message == null)
{
Console.WriteLine("MessageType option not found");
SetState(ServerState.Failed);
return;
}
DhcpFormat.MessageType messageType =
(DhcpFormat.MessageType)message.Value;
if (DhcpFormat.IsRequestMessage(messageType) == false)
{
Console.WriteLine("Inappropriate message type: {0}",
message.Value);
SetState(ServerState.Failed);
return;
}
DhcpFormat.MessageType expected = expectActions[expectIndex, 0];
DhcpFormat.MessageType action = expectActions[expectIndex, 1];
expectIndex++;
if (messageType != expected)
{
Console.WriteLine("Unexpected message type: {0} != {1}",
messageType, expected);
SetState(ServerState.Failed);
return;
}
if (DhcpFormat.IsResponseMessage(action))
{
Respond(dhcp, action);
}
if (expectIndex == expectActions.Length / expectActions.Rank)
{
SetState(ServerState.Finished);
}
}
catch (Exception e) {
Console.WriteLine("Bad Dhcp packet: {0}", e);
SetState(ServerState.Failed);
}
}
