public void ArpRequest(IPv4 sourceIP,
IPv4 targetIP,
Multiplexer !targetMux,
ArpRequestCallback callback,
object cookie,
TimeSpan timeout)
{
//
//XXXX Check pending request does not already exist!
//
EthernetAddress localMac = targetMux.Adapter.HardwareAddress;
AddPendingRequest(targetIP, callback, cookie, timeout);
// initiate an arp request...
DebugPrint("Initiating request " +
"({0},{1}) --> ({2},{3})\n",
sourceIP, localMac, targetIP, EthernetAddress.Zero);
byte[] data = new byte[ArpFormat.Size + EthernetFormat.Size];
int pos = EthernetFormat.Write(data, 0, localMac,
EthernetAddress.Broadcast,
EthernetFormat.PROTOCOL_ARP);
ArpFormat.Write(data, pos, localMac, sourceIP,
ArpFormat.Type.ARP_REQUEST, EthernetAddress.Zero,
targetIP);
NetPacket pkt = new NetPacket(data);
pkt.Mux = targetMux;
OnProtocolSend(pkt);
}
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));
}
/// <summary>
/// Check Ethernet, IP, and UDP headers match those expected.
/// </summary>
private bool ValidHeaders(NetPacket packet)
{
if (packet.Length < NonDhcpHeaderSize)
{
Console.WriteLine("Packet too short");
return(false);
}
//
// Check EthernetHeader
//
EthernetAddress originMac;
EthernetAddress targetMac;
EthernetFormat.Protocol protocol;
EthernetFormat.Read(packet,
out originMac, out targetMac, out protocol);
if (originMac != adapter.HardwareAddress)
{
Console.WriteLine("Bad origin mac: {0}", originMac);
return(false);
}
else if (targetMac != EthernetAddress.Broadcast &&
targetMac != ServerMac)
{
Console.WriteLine("Bad target mac: {0}", targetMac);
return(false);
}
else if (protocol != EthernetFormat.Protocol.IP)
{
Console.WriteLine("Bad encapsulated protocol: {0}", protocol);
return(false);
}
//
// Check IP Header
//
IPFormat.IPHeader ipHeader;
if (IPFormat.ReadIPHeader(packet, out ipHeader) == false)
{
Console.WriteLine("Failed to read IP Header");
return(false);
}
else if (ipHeader.Protocol != IPFormat.Protocol.UDP)
{
Console.WriteLine("Bad encapsulated IP protocol: {0}",
ipHeader.Protocol);
return(false);
}
else if (ipHeader.Source != IPv4.Zero &&
ipHeader.Source != assignedAddress)
{
Console.WriteLine("Bad IP source address: {0}",
ipHeader.Source);
return(false);
}
else if (ipHeader.Destination != IPv4.AllOnes &&
ipHeader.Destination != ServerAddress)
{
Console.WriteLine("Bad IP destination address: {0}",
ipHeader.Destination);
return(false);
}
Console.WriteLine("{0} {1}",
ipHeader.Source, ipHeader.Destination);
//
// Check UDP Header
//
UdpFormat.UdpHeader udpHeader;
if (UdpFormat.ReadUdpHeader(packet, out udpHeader) == false)
{
Console.WriteLine("Failed to read UDP Header");
return(false);
}
else if (udpHeader.srcPort != 68)
{
Console.WriteLine("Bad UDP source port: {0}",
udpHeader.srcPort);
return(false);
}
else if (udpHeader.dstPort != 67)
{
Console.WriteLine("Bad UDP destination port: {0}",
udpHeader.dstPort);
return(false);
}
return(true);
}
