static void PollNow(object o)
{
//Debug.WriteLine("Poll Now");
if (nic != null && nic.IsLinkUp)
{
if (!Adapter.DhcpDisabled && AreRenewing && IPAddress != null)
{
DHCP.SendMessage(DHCP.Request);
}
else if (!Adapter.DhcpDisabled && IPAddress == null)
{
DHCP.SendMessage(DHCP.Discover);
}
if (Adapter.IPAddress != null && Adapter.Gateway != null && Adapter.GatewayMac == null)
{
ARP.SendARP_Probe(Adapter.Gateway);
}
if (IPAddress != null)
{
ARP.SendARP_Gratuitus();
}
}
}
/// <summary>
/// Take care of a packet of DHCP stuff
/// </summary>
/// <param name="payload"></param>
public static void HandlePacket(byte[] payload)
{
//Debug.WriteLine("Handling DHCP packet");
// Check Transaction ID!
if (transactionID == null || payload[46] != transactionID[0] || payload[47] != transactionID[1] || payload[48] != transactionID[2] || payload[49] != transactionID[3])
{
return;
}
// To determine the type, we need to find the magic cookie, then find option 0x35h
// 02 == Offer, 05 == ACK, 06 = NAK
var options = ParseOptions(payload);
//Debug.WriteLine("DHCP PKT");
if (options.Contains("53"))
{
//Debug.WriteLine("Rec'd DHCP OFFER - 1");
if (((byte[])(options["53"]))[0] == 0x02) // Offer
{
//Debug.WriteLine("Rec'd DHCP OFFER");
ushort ipHeaderLength = (ushort)((payload[14] & 0x0f) * 4);
PendingIpAddress = Utility.ExtractRangeFromArray(payload, ipHeaderLength + 38, 4);
if (options.Contains("54"))
{
Adapter.Gateway = (byte[])options["54"]; // DHCP Server
}
if (options.Contains("6"))
{
Adapter.DomainNameServer = (byte[])options["6"]; // DNS Server
}
if (options.Contains("1"))
{
Adapter.SubnetMask = (byte[])options["1"]; // Subnet
}
if (options.Contains("3"))
{
Adapter.Gateway = (byte[])options["3"]; // Router
}
if (options.Contains("58"))
{
RenewTimer.Change((int)(((byte[])options["58"]).ToInt() * 1050), TwoHoursInMilliseconds); // Got a Renew time
}
if (options.Contains("51"))
{
RenewTimer.Change((int)(((byte[])options["51"]).ToInt() * 750), TwoHoursInMilliseconds); // Got a Lease Time (I am using 750, so we renew after 75% of lease has been consumed)
}
Adapter.GatewayMac = Utility.ExtractRangeFromArray(payload, 6, 6); // Initial gateway MAC. Will get confirmed/updated by an ARP Probe
SendMessage(DHCP.Request);
}
else if (((byte[])options["53"])[0] == 0x05) // ACK or Acknowledgement
{
// Parse out the Gateway, DNS Servers, IP address, and apply set all the variables with it...
//Debug.WriteLine("Rec'd DHCP ACK");
if (options.Contains("54"))
{
Adapter.Gateway = (byte[])options["54"]; // DHCP Server
}
if (options.Contains("6"))
{
Adapter.DomainNameServer = (byte[])options["6"]; // DNS Server
}
if (options.Contains("1"))
{
Adapter.SubnetMask = (byte[])options["1"]; // Subnet
}
if (options.Contains("3"))
{
Adapter.Gateway = (byte[])options["3"]; // Router
}
if (options.Contains("58"))
{
RenewTimer.Change((int)(((byte[])options["58"]).ToInt() * 1050), TwoHoursInMilliseconds); // Got a Renew time
}
if (options.Contains("51"))
{
RenewTimer.Change((int)(((byte[])options["51"]).ToInt() * 750), TwoHoursInMilliseconds); // Got a Lease Time (I am using 750, so we renew after 75% of lease has been consumed)
}
Adapter.GatewayMac = Utility.ExtractRangeFromArray(payload, 6, 6); // Initial gateway MAC. Will get confirmed/updated by an ARP Probe
transactionID = null;
Adapter.AreRenewing = false;
Adapter.IPAddress = PendingIpAddress ?? Adapter.IPAddress;
Adapter.startupHold.Set(); // This will release the Adapter.Start() Method! (if waiting)
Debug.WriteLine("DHCP SUCCESS! We have an IP Address - " + Adapter.IPAddress.ToAddress() + "; Gateway: " + Adapter.Gateway.ToAddress());
ARP.SendARP_Probe(Adapter.Gateway); // Confirm Gateway MAC address
}
else if (((byte[])options["53"])[0] == 0x06) // NACK or Not Acknowledged!
{
Debug.WriteLine("DHCP N-ACK");
transactionID = null;
Adapter.AreRenewing = false;
// We have failed to get an IP address for some reason...!
Adapter.IPAddress = null;
Adapter.Gateway = null;
Adapter.GatewayMac = null;
}
}
}
