private void ParseOptions(Stream s, List <DhcpOption> options)
{
while (true)
{
DhcpOption option = DhcpOption.Parse(s);
if (option.Code == DhcpOptionCode.End)
{
break;
}
if (option.Code == DhcpOptionCode.Pad)
{
continue;
}
bool optionExists = false;
foreach (DhcpOption existingOption in options)
{
if (existingOption.Code == option.Code)
{
//option already exists so append current option value into existing option
existingOption.AppendOptionValue(option);
optionExists = true;
break;
}
}
if (optionExists)
{
continue;
}
//add option to list
options.Add(option);
switch (option.Code)
{
case DhcpOptionCode.DhcpMessageType:
_dhcpMessageType = option as DhcpMessageTypeOption;
break;
case DhcpOptionCode.ClientIdentifier:
_clientIdentifier = option as ClientIdentifierOption;
break;
case DhcpOptionCode.HostName:
_hostName = option as HostNameOption;
break;
case DhcpOptionCode.ClientFullyQualifiedDomainName:
_clientFullyQualifiedDomainName = option as ClientFullyQualifiedDomainNameOption;
break;
case DhcpOptionCode.ParameterRequestList:
_parameterRequestList = option as ParameterRequestListOption;
break;
case DhcpOptionCode.MaximumDhcpMessageSize:
_maximumDhcpMessageSize = option as MaximumDhcpMessageSizeOption;
break;
case DhcpOptionCode.ServerIdentifier:
_serverIdentifier = option as ServerIdentifierOption;
break;
case DhcpOptionCode.RequestedIpAddress:
_requestedIpAddress = option as RequestedIpAddressOption;
break;
case DhcpOptionCode.OptionOverload:
_optionOverload = option as OptionOverloadOption;
break;
}
}
}
public DhcpMessage(Stream s)
{
byte[] buffer = new byte[4];
s.ReadBytes(buffer, 0, 4);
_op = (DhcpMessageOpCode)buffer[0];
_htype = (DhcpMessageHardwareAddressType)buffer[1];
_hlen = buffer[2];
_hops = buffer[3];
_xid = s.ReadBytes(4);
s.ReadBytes(buffer, 0, 4);
_secs = new byte[2];
Buffer.BlockCopy(buffer, 0, _secs, 0, 2);
Array.Reverse(buffer);
_flags = (DhcpMessageFlags)BitConverter.ToUInt16(buffer, 0);
s.ReadBytes(buffer, 0, 4);
_ciaddr = new IPAddress(buffer);
s.ReadBytes(buffer, 0, 4);
_yiaddr = new IPAddress(buffer);
s.ReadBytes(buffer, 0, 4);
_siaddr = new IPAddress(buffer);
s.ReadBytes(buffer, 0, 4);
_giaddr = new IPAddress(buffer);
_chaddr = s.ReadBytes(16);
_clientHardwareAddress = new byte[_hlen];
Buffer.BlockCopy(_chaddr, 0, _clientHardwareAddress, 0, _hlen);
_sname = s.ReadBytes(64);
_file = s.ReadBytes(128);
//read options
List <DhcpOption> options = new List <DhcpOption>();
_options = options;
s.ReadBytes(buffer, 0, 4);
uint magicCookie = BitConverter.ToUInt32(buffer, 0);
if (magicCookie == MAGIC_COOKIE)
{
ParseOptions(s, options);
if (_optionOverload != null)
{
if (_optionOverload.Value.HasFlag(OptionOverloadValue.FileFieldUsed))
{
using (MemoryStream mS = new MemoryStream(_file))
{
ParseOptions(mS, options);
}
}
if (_optionOverload.Value.HasFlag(OptionOverloadValue.SnameFieldUsed))
{
using (MemoryStream mS = new MemoryStream(_sname))
{
ParseOptions(mS, options);
}
}
}
//parse all option values
foreach (DhcpOption option in options)
{
option.ParseOptionValue();
}
}
if (_clientIdentifier == null)
{
_clientIdentifier = new ClientIdentifierOption((byte)_htype, _clientHardwareAddress);
}
if (_maximumDhcpMessageSize != null)
{
_maximumDhcpMessageSize = new MaximumDhcpMessageSizeOption(576);
}
}