/// <summary>
/// Decode the raw packet.
/// </summary>
/// <param name="data">The raw packet</param>
/// <returns>Number of bits read</returns>
public override int Decode(byte[] data)
{
// Decode the Long Header
int cursor = base.Decode(data);
// Verify Packet type and read reserved bits
if (PacketType != 0)
{
throw new CorruptedPacketException("Wrong packet type");
}
_reservedBits = BitUtils.ReadNBits(_reservedBitsIndex, data, 2);
// Read and verify the range for PacketNumberLength (1 to 4)
PacketNumberLength = BitUtils.ReadNBits(_packetNumberLengthBitsIndex, data, 2) + 1;
if (PacketNumberLength >= 5 || PacketNumberLength == 0)
{
throw new Exception("Invalid packet Number Length");
}
// Read and decode both token length and actual token
cursor += TokenLength.Decode(cursor, data);
Token = new byte[TokenLength.Value];
Array.Copy(data, cursor / 8, Token, 0, (uint)TokenLength.Value);
cursor += 8 * Convert.ToInt32(TokenLength.Value);
// Verify that the packet length is the announced length
cursor += Length.Decode(cursor, data);
if ((UInt64)data.Length != Length.Value + (UInt64)cursor / 8)
{
throw new CorruptedPacketException($"Initial packet does not have the correct size. Expected: {Length.Value + (UInt64)cursor / 8} | Actual: {data.Length}");
}
// Read the packet number
PacketNumber = (uint)BitUtils.ReadNBytes(cursor, data, PacketNumberLength);
cursor += (Int32)PacketNumberLength * 8;
// Read the rest of the payload
Payload = new byte[data.Length - (cursor / 8)];
Array.Copy(data, cursor / 8, Payload, 0, Payload.Length);
cursor += 8 * Payload.Length;
return(cursor);
}
/*
+-+-+-+-+-+-+-+-+
|1|1| 2 |R R|P P|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version (32) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| DCID Len (8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Destination Connection ID (0..160) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SCID Len (8) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Connection ID (0..160) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length (i) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Packet Number (8/16/24/32) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload (*) ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
/// <summary>
/// Decode the raw packet to a HandshakePacket.
/// </summary>
/// <param name="data">The raw packet</param>
/// <returns>Number of bits read</returns>
public override int Decode(byte[] data)
{
int cursor = base.Decode(data);
// Verify the PacketType
if (PacketType != 2)
{
throw new CorruptedPacketException("Wrong packet type");
}
// Read the reserved bits (though they currently are not used)
_reservedBits = BitUtils.ReadNBits(_reservedBitsIndex, data, 2);
// Read and verify the range for PacketNumberLength (1 to 4)
PacketNumberLength = BitUtils.ReadNBits(_packetNumberLengthBitsIndex, data, 2) + 1;
if (PacketNumberLength >= 5 || PacketNumberLength == 0)
{
throw new Exception("Invalid packet Number Length");
}
// Verify that the packet length is the announced length
cursor += Length.Decode(cursor, data);
if ((UInt64)data.Length != Length.Value + (UInt64)cursor / 8)
{
throw new CorruptedPacketException($"Handshake packet does not have the correct size. Expected: {Length.Value + (UInt64)cursor / 8} | Actual: {data.Length}");
}
// Read the packet number
PacketNumber = (uint)BitUtils.ReadNBytes(cursor, data, PacketNumberLength);
cursor += (Int32)PacketNumberLength * 8;
// Read the rest of the payload
Payload = new byte[data.Length - (cursor / 8)];
Array.Copy(data, cursor / 8, Payload, 0, Payload.Length);
cursor += 8 * Payload.Length;
return(cursor);
}
/// <summary>
/// Decode the raw packet to a RTTPacket.
/// </summary>
/// <param name="data">The raw packet</param>
/// <returns>Number of bits read</returns>
public override int Decode(byte[] data)
{
// Decode the Long Header
int cursor = base.Decode(data);
// Verify Packet Type, read reserved bits
if (PacketType != 1)
{
throw new CorruptedPacketException("Wrong packet type");
}
_reservedBits = BitUtils.ReadNBits(_reservedBitsIndex, data, 2);
// Verify that PacketNumberLength is between 1 and 4
PacketNumberLength = BitUtils.ReadNBits(_packetNumberLengthBitsIndex, data, 2) + 1;
if (PacketNumberLength >= 5 || PacketNumberLength == 0)
{
throw new Exception("Invalid packet Number Length");
}
// Verify that the length of the received packet is the same as announced
cursor += Length.Decode(cursor, data);
if ((UInt64)data.Length != Length.Value + (UInt64)cursor / 8)
{
throw new CorruptedPacketException($"0-RTT packet does not have the correct size. Expected: {Length.Value + (UInt64)cursor / 8} | Actual: {data.Length}");
}
// Read Packet Number
PacketNumber = (uint)BitUtils.ReadNBytes(cursor, data, PacketNumberLength);
cursor += (Int32)PacketNumberLength * 8;
// Read the rest of the payload.
Payload = new byte[data.Length - (cursor / 8)];
Array.Copy(data, cursor / 8, Payload, 0, Payload.Length);
cursor += 8 * Payload.Length;
return(cursor);
}