public static DhcpPacket CreateFromRaw(byte[] rawPacket)
{
DhcpPacket packet = new DhcpPacket();
using (var reader = new BinaryReader(new MemoryStream(rawPacket)))
{
packet.MessageType = (DhcpMessageType)reader.ReadByte();
HardwareAddressType hardwareAddressType = (HardwareAddressType)reader.ReadByte();
byte hardwareAddressLength = reader.ReadByte();
packet.Hops = reader.ReadByte();
packet.TransactionId = (uint)IPAddress.NetworkToHostOrder(reader.ReadInt32());
packet.SecondsElapsed = (ushort)IPAddress.NetworkToHostOrder(reader.ReadInt16());
packet.Flags = (ushort)IPAddress.NetworkToHostOrder(reader.ReadInt16());
packet.ClientAddress = new IPAddress(reader.ReadBytes(4));
packet.YourClientAddress = new IPAddress(reader.ReadBytes(4));
packet.NextServerAddress = new IPAddress(reader.ReadBytes(4));
packet.RelayAgentAddress = new IPAddress(reader.ReadBytes(4));
packet.HardwareAddress = new HardwareAddress(hardwareAddressType,
reader.ReadBytes(hardwareAddressLength));
reader.ReadBytes(16 - hardwareAddressLength); // padding
packet.ServerName = Encoding.ASCII.GetString(reader.ReadBytes(64));
packet.BootFileName = Encoding.ASCII.GetString(reader.ReadBytes(128));
int packetMagicCookie = IPAddress.NetworkToHostOrder(reader.ReadInt32());
if (packetMagicCookie != MagicCookie)
{
throw new InvalidDataException("Magic cookie not found!");
}
byte messageType = reader.ReadByte();
if (messageType != 53)
{
throw new InvalidDataException("Options should start with Message type!");
}
reader.ReadByte(); // length
packet.MessageType = (DhcpMessageType)reader.ReadByte();
var optionFactory = new DhcpOptionFactory();
byte optionType = reader.ReadByte();
while (optionType != 255)
{
DhcpOptionType type = (DhcpOptionType)optionType;
byte length = reader.ReadByte();
byte[] optionData = reader.ReadBytes(length);
DhcpOption option = optionFactory.CreateFromRaw(type, optionData);
if (option != null)
{
packet.Options.Add(option);
}
else
{
Console.WriteLine($"WARN: Unsupported option type: {type}");
}
optionType = reader.ReadByte();
}
}
return(packet);
}
public void TryGetShouldReturnNullWhenDataNotValid()
{
byte[] option = new byte[] { 255, 3, 65, 66 };
var factory = new DhcpOptionFactory();
var result = factory.TryGetOption(option);
Assert.Null(result);
}
public void ShouldThrowWhenOptionLengthIncorrect2()
{
byte[] option = new byte[] { 255, 1, 65, 66 };
var factory = new DhcpOptionFactory();
Assert.Throws <ArgumentException>(() => {
var result = factory.GetOption(option);
});
}
public void ShouldThrowWhenMessageTypeOptionLengthIncorrect()
{
byte[] option = new byte[] { 53, 2, 3, 5 };
var factory = new DhcpOptionFactory();
Assert.Throws <ArgumentException>(() => {
var result = factory.GetOption(option) as DhcpMessageTypeOption;
});
}
public void TryGetReturnsValidRequestedIpOption()
{
byte[] option = new byte[] { 0x32, 0x4, 0xc0, 0xa8, 0x01, 0x07 };
var factory = new DhcpOptionFactory();
var result = factory.TryGetOption(option) as DhcpRequestedIpAddressOption;
Assert.NotNull(result);
Assert.Equal(IPAddress.Parse("192.168.1.7"), result.RequestedIp);
}
public void TryGetReturnsValidOption()
{
byte[] option = new byte[] { 53, 2, 65, 66 };
var factory = new DhcpOptionFactory();
var result = factory.TryGetOption(option);
Assert.NotNull(result);
Assert.Equal("AB", result.GetStringValue());
}
public void CreatesGenericDhcpOption()
{
byte[] option = new byte[] { 255, 2, 65, 66 };
var factory = new DhcpOptionFactory();
var result = factory.GetOption(option);
Assert.Equal(255, result.Type);
Assert.Equal(2, result.Length);
Assert.Equal(new byte[] { 65, 66 }, result.Value);
Assert.Equal("AB", result.GetStringValue());
}
public void CreatesMessagesTypeOption()
{
byte[] option = new byte[] { 53, 1, 3 };
var factory = new DhcpOptionFactory();
var result = factory.GetOption(option) as DhcpMessageTypeOption;
Assert.NotNull(result); //verifies the returned type is correct.
Assert.Equal(53, result.Type);
Assert.Equal(1, result.Length);
Assert.Equal(DhcpMessageType.Request, result.MessageType);
}
public void CreatesVendorClassIdOption()
{
byte[] option = new byte[] { 60, 6, 65, 66, 67, 68, 69, 70 };
var factory = new DhcpOptionFactory();
var result = factory.GetOption(option) as DhcpVendorClassIdentifierOption;
Assert.NotNull(result); //verifies the returned type is correct.
Assert.Equal(60, result.Type);
Assert.Equal(6, result.Length);
Assert.Equal("ABCDEF", result.VendorClassId);
}
public void CreatesDhcpHostnameOption()
{
byte[] option = new byte[] { 12, 6, 65, 66, 67, 68, 69, 70 };
var factory = new DhcpOptionFactory();
var result = factory.GetOption(option) as DhcpHostnameOption;
Assert.NotNull(result); //verifies the returned type is correct.
Assert.Equal(12, result.Type);
Assert.Equal(6, result.Length);
Assert.Equal("ABCDEF", result.HostName);
}
public void CreatesDhcpClientIdOption()
{
byte[] option = new byte[] { 61, 7, 1, 0x8c, 0x70, 0x5a, 1, 2, 3 };
var factory = new DhcpOptionFactory();
var result = factory.GetOption(option) as DhcpClientIdentifierOption;
Assert.NotNull(result); //verifies the returned type is correct.
Assert.Equal(61, result.Type);
Assert.Equal(7, result.Length);
Assert.Equal(ArpHardwareType.Ethernet, result.HardwareType);
Assert.Equal(new byte[] { 0x8c, 0x70, 0x5a, 1, 2, 3 }, result.ClientMACAddress.GetAddressBytes());
}
