/// <summary>
/// Handles a DHCP frame and sends responses or leases addresses according to its contents
/// </summary>
/// <param name="dhcFrame">The DHCP frame to handle</param>
/// <param name="udpFrame">The UDP frame</param>
/// <param name="ipFrame">The IP frame</param>
/// <param name="tdf">The traffic description frame</param>
/// <param name="fInputFrame">The original root frame</param>
protected virtual void HandleDHCPFrame(DHCPFrame dhcFrame, eExNetworkLibrary.UDP.UDPFrame udpFrame, eExNetworkLibrary.IP.IPFrame ipFrame, TrafficDescriptionFrame tdf, Frame fInputFrame)
{
bool bIsRequest = false;
bool bIsDiscover = false;
foreach (DHCPTLVItem tlvItem in dhcFrame.GetDHCPTLVItems())
{
if (tlvItem.DHCPOptionType == DHCPOptions.DHCPMessageType)
{
if (dhcFrame.MessageType == DHCPType.BootRequest && (DHCPMessageType)tlvItem.Data[0] == DHCPMessageType.Discover)
{
bIsDiscover = true;
break;
}
if (dhcFrame.MessageType == DHCPType.BootRequest && (DHCPMessageType)tlvItem.Data[0] == DHCPMessageType.Request && lOpenServerTransactions.Contains(dhcFrame.TransactionID))
{
bIsRequest = true;
break;
}
}
}
if (bIsRequest)
{
#region Server Process request
MACAddress mClientID = dhcFrame.ClientMac;
if (tdf != null && tdf.SourceInterface != null)
{
if (dictInterfacePool.ContainsKey(tdf.SourceInterface))
{
IPAddress ipaAddressRequestet = IPAddress.Any;
string strHostname = "";
foreach (DHCPTLVItem tlvItemSearch in dhcFrame.GetDHCPTLVItems())
{
if (tlvItemSearch.DHCPOptionType == DHCPOptions.AddressRequest)
{
ipaAddressRequestet = new IPAddress(tlvItemSearch.Data);
}
if (tlvItemSearch.DHCPOptionType == DHCPOptions.Hostname)
{
strHostname = ASCIIEncoding.ASCII.GetString(tlvItemSearch.Data);
}
}
DHCPPool dhPool = dictInterfacePool[tdf.SourceInterface];
DHCPPoolItem dhItem = dhPool.GetItemForAddress(ipaAddressRequestet);
if (dhItem != null)
{
IPAddress ipaServer = tdf.SourceInterface.IpAddresses[0];
IPAddress offeredAddress = dhItem.Address;
DHCPFrame newDHCPFrame = new DHCPFrame();
newDHCPFrame.ClientAddress = IPAddress.Any;
newDHCPFrame.ClientMac = mClientID;
newDHCPFrame.Hardwarelen = 6;
newDHCPFrame.HardwareType = eExNetworkLibrary.HardwareAddressType.Ethernet;
newDHCPFrame.Hops = 0;
newDHCPFrame.MessageType = DHCPType.BootReply;
newDHCPFrame.OfferedAddress = offeredAddress;
newDHCPFrame.RelayAddress = IPAddress.Any;
newDHCPFrame.RequestedFile = "";
newDHCPFrame.RequestedServerName = "";
newDHCPFrame.Secs = dhcFrame.Secs + 1;
newDHCPFrame.ServerAddress = ipaServer;
newDHCPFrame.ValidIPFlag = true;
newDHCPFrame.TransactionID = dhcFrame.TransactionID;
DHCPTLVItem tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DHCPMessageType;
tlvItem.Data = new byte[] { (byte)DHCPMessageType.ACK };
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.ClientID;
byte[] bIDData = new byte[7];
bIDData[0] = (byte)HardwareAddressType.Ethernet;
mClientID.AddressBytes.CopyTo(bIDData, 1);
tlvItem.Data = bIDData;
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.SubnetMask;
tlvItem.Data = dhItem.Netmask.MaskBytes;
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.Router;
tlvItem.Data = dhItem.Gateway.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DomainNameServer;
tlvItem.Data = dhItem.DNSServer.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.LeaseTime;
tlvItem.Data = BitConverter.GetBytes(iLeaseDuration);
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DHCPServerID;
tlvItem.Data = ipaServer.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
UDP.UDPFrame newUDPFrame = new eExNetworkLibrary.UDP.UDPFrame();
newUDPFrame.DestinationPort = iDHCPInPort;
newUDPFrame.SourcePort = iDHCPOutPort;
newUDPFrame.EncapsulatedFrame = newDHCPFrame;
IP.IPv4Frame newIPv4Frame = new eExNetworkLibrary.IP.IPv4Frame();
newIPv4Frame.Version = 4;
newIPv4Frame.DestinationAddress = IPAddress.Broadcast;
newIPv4Frame.SourceAddress = ipaServer;
newIPv4Frame.Protocol = eExNetworkLibrary.IP.IPProtocol.UDP;
newIPv4Frame.EncapsulatedFrame = newUDPFrame;
newIPv4Frame.Identification = (uint)IncrementIPIDCounter();
newIPv4Frame.TimeToLive = 128;
TrafficDescriptionFrame tdFrame = new TrafficDescriptionFrame(null, DateTime.Now);
tdFrame.EncapsulatedFrame = newIPv4Frame;
tdf.SourceInterface.Send(tdFrame, IPAddress.Broadcast);
dhItem.LeasedTo = mClientID;
dhItem.LeasedToHostname = strHostname;
dhItem.LeaseDuration = new TimeSpan(0, 0, 0, iLeaseDuration, 0);
lOpenServerTransactions.Remove(newDHCPFrame.TransactionID);
InvokeAddressLeased(new DHCPServerEventArgs(dhPool, dhItem, tdf.SourceInterface));
}
}
}
#endregion
}
else if (bIsDiscover)
{
#region Server Process discover
MACAddress mClientID = dhcFrame.ClientMac;
if (tdf != null && tdf.SourceInterface != null)
{
if (dictInterfacePool.ContainsKey(tdf.SourceInterface))
{
DHCPPool dhPool = dictInterfacePool[tdf.SourceInterface];
DHCPPoolItem dhItem = dhPool.GetNextFreeAddress();
if (dhItem != null)
{
IPAddress ipaServer = tdf.SourceInterface.IpAddresses[0];
IPAddress offeredAddress = dhItem.Address;
DHCPFrame newDHCPFrame = new DHCPFrame();
newDHCPFrame.ClientAddress = IPAddress.Any;
newDHCPFrame.ClientMac = mClientID;
newDHCPFrame.Hardwarelen = 6;
newDHCPFrame.HardwareType = eExNetworkLibrary.HardwareAddressType.Ethernet;
newDHCPFrame.Hops = 0;
newDHCPFrame.MessageType = DHCPType.BootReply;
newDHCPFrame.OfferedAddress = offeredAddress;
newDHCPFrame.RelayAddress = IPAddress.Any;
newDHCPFrame.RequestedFile = "";
newDHCPFrame.RequestedServerName = "";
newDHCPFrame.Secs = dhcFrame.Secs + 1;
newDHCPFrame.ServerAddress = ipaServer;
newDHCPFrame.ValidIPFlag = true;
newDHCPFrame.TransactionID = dhcFrame.TransactionID;
DHCPTLVItem tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DHCPMessageType;
tlvItem.Data = new byte[] { (byte)DHCPMessageType.Offer };
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.ClientID;
byte[] bIDData = new byte[7];
bIDData[0] = (byte)HardwareAddressType.Ethernet;
mClientID.AddressBytes.CopyTo(bIDData, 1);
tlvItem.Data = bIDData;
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.SubnetMask;
tlvItem.Data = dhItem.Netmask.MaskBytes;
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.Router;
tlvItem.Data = dhItem.Gateway.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DomainNameServer;
tlvItem.Data = dhItem.DNSServer.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.LeaseTime;
tlvItem.Data = BitConverter.GetBytes(86400);
newDHCPFrame.AddDHCPTLVItem(tlvItem);
tlvItem = new DHCPTLVItem();
tlvItem.DHCPOptionType = DHCPOptions.DHCPServerID;
tlvItem.Data = ipaServer.GetAddressBytes();
newDHCPFrame.AddDHCPTLVItem(tlvItem);
UDP.UDPFrame newUDPFrame = new eExNetworkLibrary.UDP.UDPFrame();
newUDPFrame.DestinationPort = iDHCPInPort;
newUDPFrame.SourcePort = iDHCPOutPort;
newUDPFrame.EncapsulatedFrame = newDHCPFrame;
IP.IPv4Frame newIPv4Frame = new eExNetworkLibrary.IP.IPv4Frame();
newIPv4Frame.Version = 4;
newIPv4Frame.DestinationAddress = IPAddress.Broadcast;
newIPv4Frame.SourceAddress = ipaServer;
newIPv4Frame.Protocol = eExNetworkLibrary.IP.IPProtocol.UDP;
newIPv4Frame.EncapsulatedFrame = newUDPFrame;
newIPv4Frame.Identification = (uint)IncrementIPIDCounter();
newIPv4Frame.TimeToLive = 128;
TrafficDescriptionFrame tdFrame = new TrafficDescriptionFrame(null, DateTime.Now);
tdFrame.EncapsulatedFrame = newIPv4Frame;
tdf.SourceInterface.Send(tdFrame, IPAddress.Broadcast);
lOpenServerTransactions.Add(newDHCPFrame.TransactionID);
}
}
}
#endregion
}
}