DHCPHeader DecodeBytes(byte[] data)
{
try
{
GCHandle handle = GCHandle.Alloc(data, GCHandleType.Pinned);
DHCPHeader temp = (DHCPHeader)Marshal.PtrToStructure(handle.AddrOfPinnedObject(), typeof(DHCPHeader));
handle.Free();
return(temp);
}
catch (Exception ee)
{
Debug.WriteLine(ee.ToString());
}
return(new DHCPHeader());
}
byte[] EncodeBytes(DHCPHeader hdr)
{
try
{
int sz = Marshal.SizeOf(hdr);
byte[] data = new byte[sz];
IntPtr ptr = Marshal.AllocHGlobal(sz);
Marshal.StructureToPtr(hdr, ptr, true);
Marshal.Copy(ptr, data, 0, sz);
Marshal.FreeHGlobal(ptr);
return(data);
}
catch (Exception ee)
{
Debug.WriteLine(ee.ToString());
}
return(null);
}
public byte[] GetBytes()
{
if (this.MacAddress == null)
{
return(null);
}
if (this.MacAddress.Length > 16)
{
return(null);
}
if (this.SupportedDHCP9ParameterList == null || this.SupportedDHCP9ParameterList.Count == 0)
{
return(null);
}
if (this.WantedDHCP9ParameterList == null || this.WantedDHCP9ParameterList.Count == 0)
{
return(null);
}
if (this.Servername != null && this.Servername.Length > 64)
{
return(null);
}
if (this.BootFile != null && this.BootFile.Length > 128)
{
return(null);
}
DHCPHeader hdr = new DHCPHeader();
hdr.OperationCode = this.OperationCode;
hdr.HardwareType = this.HardwareType;
hdr.Magic = 0x63538263;
hdr.HardwareType = this.HardwareType;
hdr.Flags = this.Flags;
hdr.CIAddr = this.IPClient.GetAddressUint();
hdr.GIAddr = this.IPGateway.GetAddressUint();
hdr.YIAddr = this.IPYours.GetAddressUint();
hdr.SIAddr = this.IPServer.GetAddressUint();
hdr.XID = this.XID;
hdr.MACLength = (byte)this.MacAddress.Length;
hdr.CHAddr = new byte[16];
Buffer.BlockCopy(this.MacAddress, 0, hdr.CHAddr, 0, this.MacAddress.Length);
if (this.BootFile != null)
{
hdr.File = Encoding.ASCII.GetBytes(this.BootFile.PadRight(128, '\0'));
}
if (this.Servername != null)
{
hdr.SName = Encoding.ASCII.GetBytes(this.Servername.PadRight(64, '\0'));
}
byte[] headerdata = EncodeBytes(hdr);
List <DHCPOption> DHCPOptions = new List <DHCPOption>();
DHCPOption nonopto = new DHCPOption();
nonopto.Type = 53;
nonopto.Size = 1;
nonopto.Data = new byte[1];
nonopto.Data[0] = (byte)this.DHCP53MessageType;
DHCPOptions.Add(nonopto);
nonopto = new DHCPOption();
nonopto.Type = 54;
nonopto.Size = 4;
nonopto.Data = this.IPServer.GetAddressBytes();
DHCPOptions.Add(nonopto);
foreach (byte code in SupportedDHCP9ParameterList)
{
if (WantedDHCP9ParameterList.Contains(code) == false)
{
continue;
}
DHCPOption o = new DHCPOption();
switch (code)
{
case 60:
if (DHCP60ClassIdentifier == null)
{
continue;
}
o.Type = 60;
o.Data = Encoding.ASCII.GetBytes(DHCP60ClassIdentifier);
if (o.Data.Length > 128)
{
continue;
}
o.Size = (byte)o.Data.Length;
break;
case 66:
if (DHCP66BootServer == null)
{
continue;
}
o.Type = 66;
o.Data = Encoding.ASCII.GetBytes(DHCP66BootServer.Trim() + "\0");
if (o.Data.Length > 128)
{
continue;
}
o.Size = (byte)o.Data.Length;
break;
case 67:
if (DHCP67BootFilename == null)
{
continue;
}
o.Type = 67;
o.Data = Encoding.ASCII.GetBytes(DHCP67BootFilename.Trim() + "\0");
if (o.Data.Length > 128)
{
continue;
}
o.Size = (byte)o.Data.Length;
break;
case 43:
if (DHCP43VendorSpecificInfo == null)
{
continue;
}
o.Type = 43;
o.Data = DHCP43VendorSpecificInfo;
if (o.Data.Length > 128)
{
continue;
}
o.Size = (byte)o.Data.Length;
break;
}
DHCPOptions.Add(o);
}
int size = headerdata.Length;
foreach (DHCPOption o in DHCPOptions)
{
size += 2 + o.Data.Length;
}
size++;
byte[] data = new byte[size];
Buffer.BlockCopy(headerdata, 0, data, 0, headerdata.Length);
size = headerdata.Length;
foreach (DHCPOption o in DHCPOptions)
{
data[size + 0] = o.Type;
data[size + 1] = o.Size;
Buffer.BlockCopy(o.Data, 0, data, size + 2, o.Data.Length);
size += 2 + o.Data.Length;
}
data[data.Length - 1] = 0xFF;
return(data);
}
public DHCPPacket(byte[] data)
{
DHCPHdr = DecodeBytes(data);
if (DHCPHdr.Magic != 0x63538263)
{
Malformed = true;
return;
}
if (DHCPHdr.MACLength > 16)
{
Malformed = true;
return;
}
for (int i = 0xF0; i < data.Length;)
{
if (data[i] == 0xFF)
{
break;
}
if (data.Length - i < 2)
{
Malformed = true;
break;
}
DHCPOption o = new DHCPOption();
o.Type = data[i + 0];
o.Size = data[i + 1];
if (o.Type == 0 || o.Size == 0)
{
Malformed = true;
break;
}
if (data.Length - (i + o.Size) < 0)
{
Malformed = true;
break;
}
o.Data = new byte[o.Size];
Buffer.BlockCopy(data, i + 2, o.Data, 0, o.Size);
DHCPOptions.Add(o);
i += 2 + o.Size;
}
foreach (DHCPOption o in DHCPOptions)
{
switch (o.Type)
{
case 97:
if (o.Size != 17)
{
Malformed = true;
continue;
}
DHCP97ClientUUID = BytesToString(o.Data, 1);
break;
case 61:
//if (o.Size != 17)
//{
// Malformed = true;
// continue;
//}
DHCP61ClientGUID = BytesToString(o.Data, 1);
break;
case 55:
DHCP9ReqParameterList = new List <byte>();
foreach (byte b in o.Data)
{
if (b == 0 || b == 0xff)
{
Malformed = true;
}
if (DHCP9ReqParameterList.Contains(b) == false)
{
DHCP9ReqParameterList.Add(b);
}
}
break;
case 53:
if (o.Size != 1)
{
Malformed = true;
continue;
}
DHCP53MessageType = (DHCPMessageType)o.Data[0];
break;
case 57:
if (o.Size != 2)
{
Malformed = true;
continue;
}
DHCP57MessageLength = BitConverter.ToUInt16(o.Data.Reverse().ToArray(), 0);
break;
case 60:
if (o.Size != 32)
{
Malformed = true;
continue;
}
DHCP60ClassIdentifier = Encoding.ASCII.GetString(o.Data);
break;
case 66:
DHCP66BootServer = Encoding.ASCII.GetString(o.Data).NullTrim();
break;
case 67:
DHCP67BootFilename = Encoding.ASCII.GetString(o.Data).NullTrim();
break;
case 93:
if (o.Size != 2)
{
Malformed = true;
continue;
}
DHCP93Architecture = (DHCPArchitecture)BitConverter.ToUInt16(o.Data.Reverse().ToArray(), 0);
break;
case 94:
if (o.Size != 3)
{
Malformed = true;
continue;
}
if (o.Data[0] == 1)
{
DHCP94ClientNIC = "UNDI.";
}
else
{
DHCP94ClientNIC = "UNKN.";
}
DHCP94ClientNIC += o.Data[1].ToString("0") + "." + o.Data[2].ToString("0");
break;
default:
Debug.WriteLine("Unknown code: " + o.Type.ToString() + " (0x" + o.Type.ToString("X2") + ")");
break;
}
}
Flags = DHCPHdr.Flags;
OperationCode = DHCPHdr.OperationCode;
HardwareType = DHCPHdr.HardwareType;
XID = DHCPHdr.XID;
IPClient = new IPAddress(DHCPHdr.CIAddr);
IPYours = new IPAddress(DHCPHdr.YIAddr);
IPServer = new IPAddress(DHCPHdr.SIAddr);
IPGateway = new IPAddress(DHCPHdr.GIAddr);
MacAddress = new byte[DHCPHdr.MACLength];
Buffer.BlockCopy(DHCPHdr.CHAddr, 0, MacAddress, 0, DHCPHdr.MACLength);
Servername = Encoding.ASCII.GetString(DHCPHdr.SName).NullTrim();
BootFile = Encoding.ASCII.GetString(DHCPHdr.File).NullTrim();
}
