private void SendResponsePacket(DhcpFormat dhcp)
{
int packetSize = dhcp.Size + UdpFormat.Size +
IPFormat.Size + EthernetFormat.Size;
byte [] packet = new byte [packetSize];
// Write out DHCP packet
int dhcpSize = dhcp.Size;
int dhcpOffset = packet.Length - dhcpSize;
dhcp.Write(packet, dhcpOffset);
// Create UDP Header
UdpFormat.UdpHeader udpHeader = new UdpFormat.UdpHeader();
udpHeader.srcPort = DhcpFormat.ServerPort;
udpHeader.dstPort = DhcpFormat.ClientPort;
udpHeader.length = (ushort)(UdpFormat.Size + dhcpSize);
// Create IP Header
IPFormat.IPHeader ipHeader = new NetStack.Protocols.IPFormat.IPHeader();
ipHeader.SetDefaults(IPFormat.Protocol.UDP);
IPFormat.SetDontFragBit(ipHeader);
ipHeader.Source = ServerAddress;
ipHeader.Destination = IPv4.Broadcast;
ipHeader.totalLength = (ushort)(IPFormat.Size + UdpFormat.Size + dhcpSize);
// Write out IP and Header
int udpOffset = packet.Length - dhcp.Size - UdpFormat.Size;
int ipOffset = udpOffset - IPFormat.Size;
UdpFormat.WriteUdpPacket(packet, ipOffset,
ref ipHeader, ref udpHeader,
packet, dhcpOffset, dhcpSize);
// Add Ethernet Header
EthernetFormat.Write(packet, 0, ServerMac,
EthernetAddress.Broadcast,
EthernetFormat.Protocol.IP);
NetPacket np = new NetPacket(packet);
if (adapter.ReceivePacket(np) == false)
{
Console.WriteLine("Failed to send packet");
SetState(ServerState.Failed);
}
}
internal bool Send(EthernetAddress dstAddr, DhcpFormat !dhcp)
{
int packetSize = dhcp.Size + UdpFormat.Size +
IPFormat.Size + EthernetFormat.Size;
byte [] packet = new byte [packetSize];
// Write out DHCP packet
int dhcpSize = dhcp.Size;
int dhcpOffset = packet.Length - dhcpSize;
dhcp.Write(packet, dhcpOffset);
// Create UDP Header
UdpFormat.UdpHeader udpHeader = new UdpFormat.UdpHeader();
udpHeader.srcPort = DhcpFormat.ClientPort;
udpHeader.dstPort = DhcpFormat.ServerPort;
udpHeader.length = (ushort)(UdpFormat.Size + dhcpSize);
// Create IP Header
IPFormat.IPHeader ipHeader = new NetStack.Protocols.IPFormat.IPHeader();
ipHeader.SetDefaults(IPFormat.Protocol.UDP);
IPFormat.SetDontFragBit(ipHeader);
ipHeader.Source = IPv4.Any;
ipHeader.Destination = IPv4.Broadcast;
ipHeader.totalLength = (ushort)(IPFormat.Size + UdpFormat.Size + dhcpSize);
// Write out IP and Header
int udpOffset = packet.Length - dhcp.Size - UdpFormat.Size;
int ipOffset = udpOffset - IPFormat.Size;
UdpFormat.WriteUdpPacket(packet, ipOffset,
ipHeader, ref udpHeader,
packet, dhcpOffset, dhcpSize);
// Add Ethernet Header
EthernetFormat.Write(packet, 0, adapter.HardwareAddress,
dstAddr, EthernetFormat.PROTOCOL_IP);
NetPacket np = new NetPacket(packet);
return(udpSession.WritePacket(np));
}
public NetStatus OnProtocolReceive(NetPacket !packet)
{
DebugPrint("Received UDP packet!\n");
UdpFormat.UdpHeader udpHeader = new UdpFormat.UdpHeader();
if (UdpFormat.ReadUdpHeader(packet, out udpHeader) == false)
{
DebugPrint("UDP session received unreadable packet.\n");
return(NetStatus.Code.PROTOCOL_DROP_ERROR);
}
IPFormat.IPHeader !ipHeader = (IPFormat.IPHeader !)packet.OverlapContext;
if (udpHeader.checksum != 0 &&
UdpFormat.IsChecksumValid(ipHeader, udpHeader, packet) == false)
{
DebugPrint("UDP checksum failed. NO cigar and NO packet!");
return(NetStatus.Code.PROTOCOL_DROP_CHKSUM);
}
packet.OverlapContext = ipHeader;
ArrayList udpSessions = Core.Instance().GetSessions(this);
if (udpSessions == null)
{
DebugPrint("No UDP Sessions\n");
return(NetStatus.Code.PROTOCOL_DROP_ERROR);
}
DebugPrint("Packet : Source {0}:{1} Destination {2}:{3}\n",
ipHeader.Source, udpHeader.srcPort,
ipHeader.Destination, udpHeader.dstPort);
lock (udpSessions.SyncRoot) {
foreach (UdpSession !u in udpSessions)
{
DebugPrint("Session : Source {0}:{1} Destination {2}:{3}\n",
u.RemoteAddress, u.RemotePort,
u.LocalAddress, u.LocalPort);
// Match conditions
//
// Bound remote port is zero (not-specified)
// or matches exactly Bound remote IP is Any
// (not-specified) or matches exactly
if ((u.RemoteAddress == IPv4.Any ||
u.RemoteAddress == ipHeader.Source) &&
(u.RemotePort == 0 ||
u.RemotePort == udpHeader.srcPort) &&
(u.LocalAddress == IPv4.Any ||
u.LocalAddress == ipHeader.Destination) &&
(u.LocalPort == udpHeader.dstPort))
{
DebugPrint("Delivered to UDP session\n");
return(u.OnReceive(this, packet, udpHeader));
}
}
}
return(NetStatus.Code.PROTOCOL_DROP_ERROR);
}
