/// <summary>
/// Get the raw packet bytes
/// </summary>
/// <returns></returns>
public Byte[] GetBytes(RadiusDictionary dictionary)
{
var packetBytes = new List <Byte>
{
(Byte)Code,
Identifier
};
packetBytes.AddRange(new Byte[18]); // Placeholder for length and authenticator
var messageAuthenticatorPosition = 0;
foreach (var attribute in Attributes)
{
// todo add logic to check attribute object type matches type in dictionary?
foreach (var value in attribute.Value)
{
var contentBytes = GetAttributeValueBytes(value);
var headerBytes = new Byte[2];
dictionary.AttributeNames.TryGetValue(attribute.Key, out var attributeType);
switch (attributeType)
{
case DictionaryVendorAttribute _attributeType:
headerBytes = new Byte[8];
headerBytes[0] = 26; // VSA type
var vendorId = BitConverter.GetBytes(_attributeType.VendorId);
Array.Reverse(vendorId);
Buffer.BlockCopy(vendorId, 0, headerBytes, 2, 4);
headerBytes[6] = (Byte)_attributeType.VendorCode;
headerBytes[7] = (Byte)(2 + contentBytes.Length); // length of the vsa part
break;
case DictionaryAttribute _attributeType:
headerBytes[0] = attributeType.Code;
// Encrypt password if this is a User-Password attribute
if (_attributeType.Code == 2)
{
contentBytes = RadiusPassword.Encrypt(SharedSecret, Authenticator, contentBytes);
}
else if (_attributeType.Code == 80) // Remember the position of the message authenticator, because it has to be added after everything else
{
messageAuthenticatorPosition = packetBytes.Count;
}
break;
default:
throw new InvalidOperationException($"Unknown attribute {attribute.Key}, check spelling or dictionary");
}
headerBytes[1] = (Byte)(headerBytes.Length + contentBytes.Length);
packetBytes.AddRange(headerBytes);
packetBytes.AddRange(contentBytes);
}
}
// Note the order of the bytes...
var packetLengthBytes = BitConverter.GetBytes(packetBytes.Count);
packetBytes[2] = packetLengthBytes[1];
packetBytes[3] = packetLengthBytes[0];
var packetBytesArray = packetBytes.ToArray();
if (Code == PacketCode.AccountingRequest || Code == PacketCode.DisconnectRequest)
{
var authenticator = CalculateRequestAuthenticator(SharedSecret, packetBytesArray);
Buffer.BlockCopy(authenticator, 0, packetBytesArray, 4, 16);
}
else
{
var authenticator = _requestAuthenticator != null?CalculateResponseAuthenticator(SharedSecret, _requestAuthenticator, packetBytesArray) : Authenticator;
Buffer.BlockCopy(authenticator, 0, packetBytesArray, 4, 16);
}
if (messageAuthenticatorPosition != 0)
{
var temp = new Byte[16];
Buffer.BlockCopy(temp, 0, packetBytesArray, messageAuthenticatorPosition + 2, 16);
var messageAuthenticatorBytes = CalculateMessageAuthenticator(packetBytesArray, SharedSecret);
Buffer.BlockCopy(messageAuthenticatorBytes, 0, packetBytesArray, messageAuthenticatorPosition + 2, 16);
}
return(packetBytesArray);
}
/// <summary>
/// Parses packet bytes and returns an IRadiusPacket
/// </summary>
/// <param name="packetBytes"></param>
/// <param name="dictionary"></param>
/// <param name="sharedSecret"></param>
public static IRadiusPacket Parse(Byte[] packetBytes, RadiusDictionary dictionary, Byte[] sharedSecret)
{
var packetLength = BitConverter.ToUInt16(packetBytes.Skip(2).Take(2).Reverse().ToArray(), 0);
if (packetBytes.Length != packetLength)
{
throw new InvalidOperationException($"Packet length does not match, expected: {packetLength}, actual: {packetBytes.Length}");
}
var packet = new RadiusPacket
{
SharedSecret = sharedSecret,
Identifier = packetBytes[1],
Code = (PacketCode)packetBytes[0],
};
Buffer.BlockCopy(packetBytes, 4, packet.Authenticator, 0, 16);
if (packet.Code == PacketCode.AccountingRequest || packet.Code == PacketCode.DisconnectRequest)
{
if (!packet.Authenticator.SequenceEqual(CalculateRequestAuthenticator(packet.SharedSecret, packetBytes)))
{
throw new InvalidOperationException($"Invalid request authenticator in packet {packet.Identifier}, check secret?");
}
}
// The rest are attribute value pairs
var position = 20;
var messageAuthenticatorPosition = 0;
while (position < packetBytes.Length)
{
var typecode = packetBytes[position];
var length = packetBytes[position + 1];
if (position + length > packetLength)
{
throw new ArgumentOutOfRangeException("Go home roamserver, youre drunk");
}
var contentBytes = new Byte[length - 2];
Buffer.BlockCopy(packetBytes, position + 2, contentBytes, 0, length - 2);
try
{
if (typecode == 26) // VSA
{
var vsa = new VendorSpecificAttribute(contentBytes);
var vendorAttributeDefinition = dictionary.VendorSpecificAttributes.FirstOrDefault(o => o.VendorId == vsa.VendorId && o.VendorCode == vsa.VendorCode);
if (vendorAttributeDefinition == null)
{
_log.Info($"Unknown vsa: {vsa.VendorId}:{vsa.VendorCode}");
}
else
{
try
{
var content = ParseContentBytes(vsa.Value, vendorAttributeDefinition.Type, typecode, packet.Authenticator, packet.SharedSecret);
packet.AddAttributeObject(vendorAttributeDefinition.Name, content);
}
catch (Exception ex)
{
_log.Error($"Something went wrong with vsa {vendorAttributeDefinition.Name}", ex);
}
}
}
else
{
var attributeDefinition = dictionary.Attributes[typecode];
if (attributeDefinition.Code == 80)
{
messageAuthenticatorPosition = position;
}
try
{
var content = ParseContentBytes(contentBytes, attributeDefinition.Type, typecode, packet.Authenticator, packet.SharedSecret);
packet.AddAttributeObject(attributeDefinition.Name, content);
}
catch (Exception ex)
{
_log.Error($"Something went wrong with {attributeDefinition.Name}", ex);
_log.Debug($"Attribute bytes: {contentBytes.ToHexString()}");
}
}
}
catch (KeyNotFoundException)
{
_log.Warn($"Attribute {typecode} not found in dictionary");
}
catch (Exception ex)
{
_log.Error($"Something went wrong parsing attribute {typecode}", ex);
}
position += length;
}
if (messageAuthenticatorPosition != 0)
{
var messageAuthenticator = packet.GetAttribute <Byte[]>("Message-Authenticator");
var temp = new Byte[16];
Buffer.BlockCopy(temp, 0, packetBytes, messageAuthenticatorPosition + 2, 16);
var calculatedMessageAuthenticator = CalculateMessageAuthenticator(packetBytes, sharedSecret);
if (!calculatedMessageAuthenticator.SequenceEqual(messageAuthenticator))
{
throw new InvalidOperationException($"Invalid Message-Authenticator in packet {packet.Identifier}");
}
}
return(packet);
}
/// <summary>
/// Tries to get a packet from the stream. Returns true if successful
/// Returns false if no packet could be parsed or stream is empty ie closing
/// </summary>
/// <param name="stream"></param>
/// <param name="packet"></param>
/// <param name="dictionary"></param>
/// <returns></returns>
public static Boolean TryParsePacketFromStream(Stream stream, out IRadiusPacket packet, RadiusDictionary dictionary, Byte[] sharedSecret)
{
var packetHeaderBytes = new Byte[4];
var i = stream.Read(packetHeaderBytes, 0, 4);
if (i != 0)
{
try
{
var packetLength = BitConverter.ToUInt16(packetHeaderBytes.Reverse().ToArray(), 0);
var packetContentBytes = new Byte[packetLength - 4];
stream.Read(packetContentBytes, 0, packetContentBytes.Length);
packet = Parse(packetHeaderBytes.Concat(packetContentBytes).ToArray(), dictionary, sharedSecret);
return(true);
}
catch (Exception ex)
{
_log.Warn("Unable to parse packet from stream", ex);
}
}
packet = null;
return(false);
}
