/// <summary>This is used to process a dhcp packet on the node side, that
/// includes placing data such as the local Brunet Address, Ipop Namespace,
/// and other optional parameters in our request to the dhcp server. When
/// receiving the results, if it is successful, the results are written to
/// the TAP device.</summary>
/// <param name="ipp"> The IPPacket that contains the DHCP Request</param>
/// <param name="dhcp_params"> an object containing any extra parameters for
/// the dhcp server</param>
/// <returns> true on if dhcp is supported.</returns>
protected virtual bool HandleDHCP(IPPacket ipp)
{
UDPPacket udpp = new UDPPacket(ipp.Payload);
DHCPPacket dhcp_packet = new DHCPPacket(udpp.Payload);
MemBlock ether_addr = dhcp_packet.chaddr;
if(_dhcp_config == null) {
return true;
}
DHCPServer dhcp_server = CheckOutDHCPServer(ether_addr);
if(dhcp_server == null) {
return true;
}
MemBlock last_ip = null;
_ether_to_ip.TryGetValue(ether_addr, out last_ip);
byte[] last_ipb = (last_ip == null) ? null : (byte[]) last_ip;
WaitCallback wcb = delegate(object o) {
ProtocolLog.WriteIf(IpopLog.DHCPLog, String.Format(
"Attemping DHCP for: {0}", Utils.MemBlockToString(ether_addr, '.')));
DHCPPacket rpacket = null;
try {
rpacket = dhcp_server.ProcessPacket(dhcp_packet,
Brunet.Address.ToString(), last_ipb);
} catch(Exception e) {
ProtocolLog.WriteIf(IpopLog.DHCPLog, e.Message);
CheckInDHCPServer(dhcp_server);
return;
}
/* Check our allocation to see if we're getting a new address */
MemBlock new_addr = rpacket.yiaddr;
UpdateMapping(ether_addr, new_addr);
MemBlock destination_ip = ipp.SourceIP;
if(destination_ip.Equals(IPPacket.ZeroAddress)) {
destination_ip = IPPacket.BroadcastAddress;
}
UDPPacket res_udpp = new UDPPacket(_dhcp_server_port, _dhcp_client_port, rpacket.Packet);
IPPacket res_ipp = new IPPacket(IPPacket.Protocols.UDP, rpacket.siaddr,
destination_ip, res_udpp.ICPacket);
EthernetPacket res_ep = new EthernetPacket(ether_addr, EthernetPacket.UnicastAddress,
EthernetPacket.Types.IP, res_ipp.ICPacket);
Ethernet.Send(res_ep.ICPacket);
CheckInDHCPServer(dhcp_server);
};
ThreadPool.QueueUserWorkItem(wcb);
return true;
}
/// <summary></summary>
public DHCPPacket ProcessPacket(DHCPPacket packet, string unique_id,
byte[] last_ip, params object[] dhcp_params)
{
DHCPPacket.MessageTypes message_type = (DHCPPacket.MessageTypes)
packet.Options[DHCPPacket.OptionTypes.MESSAGE_TYPE][0];
byte[] requested_ip = last_ip;
bool renew = false;
if(message_type == DHCPPacket.MessageTypes.DISCOVER) {
message_type = DHCPPacket.MessageTypes.OFFER;
} else if(message_type == DHCPPacket.MessageTypes.REQUEST) {
if(packet.Options.ContainsKey(DHCPPacket.OptionTypes.REQUESTED_IP)) {
requested_ip = packet.Options[DHCPPacket.OptionTypes.REQUESTED_IP];
} else if(!packet.ciaddr.Equals(IPPacket.ZeroAddress)) {
requested_ip = packet.ciaddr;
}
renew = true;
message_type = DHCPPacket.MessageTypes.ACK;
} else {
throw new Exception("Unsupported message type!");
}
byte[] reply_ip = RequestLease(requested_ip, renew, unique_id, dhcp_params);
Dictionary<DHCPPacket.OptionTypes, MemBlock> options =
new Dictionary<DHCPPacket.OptionTypes, MemBlock>();
options[DHCPPacket.OptionTypes.DOMAIN_NAME] = Encoding.UTF8.GetBytes(DNS.DomainName);
// The following option is needed for dhcp to "succeed" in Vista, but they break Linux
// options[DHCPPacket.OptionTypes.ROUTER] = reply.ip;
options[DHCPPacket.OptionTypes.DOMAIN_NAME_SERVER] = MemBlock.Reference(ServerIP);
options[DHCPPacket.OptionTypes.SUBNET_MASK] = MemBlock.Reference(Netmask);
options[DHCPPacket.OptionTypes.LEASE_TIME] = _lease_time;
options[DHCPPacket.OptionTypes.MTU] = _mtu;
options[DHCPPacket.OptionTypes.SERVER_ID] = MemBlock.Reference(ServerIP);
options[DHCPPacket.OptionTypes.MESSAGE_TYPE] = MemBlock.Reference(new byte[]{(byte) message_type});
DHCPPacket rpacket = new DHCPPacket(2, packet.xid, packet.ciaddr, reply_ip,
ServerIP, packet.chaddr, options);
return rpacket;
}
