private ushort Xor(ushort port)
{
var b = port.ToBe().ToArray();
var xPort = BitUtils.FromBe((byte)(_magicCookie[0] ^ b[0]), (byte)(_magicCookie[1] ^ b[1]));
return(xPort);
}
public bool TryParse(byte[] bytes)
{
if (bytes.Length < 20)
{
return(false); // Check length
}
StunMessageType = (StunMessageType)BitUtils.FromBe((byte)(bytes[0] & 0b0011_1111), bytes[1]);
if (!Enum.IsDefined(typeof(StunMessageType), StunMessageType))
{
return(false);
}
var length = BitUtils.FromBe(bytes[2], bytes[3]);
MagicCookie = BitUtils.FromBeToInt(bytes.Skip(4).Take(4));
TransactionId = bytes.Skip(8).Take(12).ToArray();
if (bytes.Length != length + 20)
{
return(false); // Check length
}
var list = new List <Attribute>();
var b = bytes.Skip(20).ToArray();
while (b.Length > 0)
{
var attribute = new Attribute(MagicCookieBytes.ToArray(), TransactionId);
var offset = attribute.TryParse(b);
if (offset > 0)
{
list.Add(attribute);
b = b.Skip(offset).ToArray();
}
else
{
Debug.WriteLine($@"[Warning] Ignore wrong attribute: {BitConverter.ToString(b)}");
break;
}
}
Attributes = list;
return(true);
}
public bool TryParse(byte[] bytes)
{
if (bytes.Length < 2 || (bytes.Length & 1) == 1)
{
return(false);
}
var list = new List <AttributeType>();
for (var i = 0; i < bytes.Length >> 1; ++i)
{
var b = bytes.Skip(i << 1).Take(2);
list.Add((AttributeType)BitUtils.FromBe(b));
}
Types = list;
return(true);
}
/// <returns>
/// Parse 成功字节，0 则表示 Parse 失败
/// </returns>
public int TryParse(byte[] bytes)
{
if (bytes.Length < 4)
{
return(0);
}
Type = (AttributeType)BitUtils.FromBe(bytes[0], bytes[1]);
Length = BitUtils.FromBe(bytes[2], bytes[3]);
if (bytes.Length < 4 + Length)
{
return(0);
}
var value = bytes.Skip(4).Take(Length).ToArray();
IAttribute t = Type switch
{
AttributeType.MappedAddress => new MappedAddressAttribute(),
AttributeType.XorMappedAddress => new XorMappedAddressAttribute(_magicCookie, _transactionId),
AttributeType.ResponseAddress => new ResponseAddressAttribute(),
AttributeType.ChangeRequest => new ChangeRequestAttribute(),
AttributeType.SourceAddress => new SourceAddressAttribute(),
AttributeType.ChangedAddress => new ChangedAddressAttribute(),
AttributeType.OtherAddress => new OtherAddressAttribute(),
AttributeType.ReflectedFrom => new ReflectedFromAttribute(),
AttributeType.ErrorCode => new ErrorCodeAttribute(),
_ => new UselessAttribute()
};
if (t.TryParse(value))
{
Value = t;
}
return(4 + Length + (4 - Length % 4) % 4); // 对齐
}
}
public virtual bool TryParse(byte[] bytes)
{
var length = 4;
if (bytes.Length < length)
{
return(false);
}
Family = (IpFamily)bytes[1];
switch (Family)
{
case IpFamily.IPv4:
length += 4;
break;
case IpFamily.IPv6:
length += 16;
break;
default:
return(false);
}
if (bytes.Length != length)
{
return(false);
}
Port = BitUtils.FromBe(bytes[2], bytes[3]);
Address = new IPAddress(bytes.Skip(4).ToArray());
return(true);
}