private async Task SendCloseSecureChannelRequestAsync(CloseSecureChannelRequest request, CancellationToken token)
{
var bodyStream = SerializableBytes.CreateWritableStream();
var bodyEncoder = new BinaryEncoder(bodyStream, this);
try
{
bodyEncoder.WriteNodeId(null, CloseSecureChannelRequestNodeId);
request.Encode(bodyEncoder);
bodyStream.Position = 0;
if (bodyStream.Length > this.RemoteMaxMessageSize)
{
throw new ServiceResultException(StatusCodes.BadEncodingLimitsExceeded);
}
// write chunks
int chunkCount = 0;
int bodyCount = (int)(bodyStream.Length - bodyStream.Position);
while (bodyCount > 0)
{
chunkCount++;
if (this.RemoteMaxChunkCount > 0 && chunkCount > this.RemoteMaxChunkCount)
{
throw new ServiceResultException(StatusCodes.BadEncodingLimitsExceeded);
}
var stream = new MemoryStream(this.sendBuffer, 0, (int)this.RemoteReceiveBufferSize, true, true);
var encoder = new BinaryEncoder(stream, this);
try
{
// header
encoder.WriteUInt32(null, UaTcpMessageTypes.CLOF);
encoder.WriteUInt32(null, 0u);
encoder.WriteUInt32(null, this.ChannelId);
// symmetric security header
encoder.WriteUInt32(null, this.TokenId);
// detect new TokenId
if (this.TokenId != this.currentClientTokenId)
{
this.currentClientTokenId = this.TokenId;
// update signer and encrypter with new symmetric keys
if (this.symIsSigned)
{
this.symSigner.Key = this.clientSigningKey;
if (this.symIsEncrypted)
{
this.currentClientEncryptingKey = this.clientEncryptingKey;
this.currentClientInitializationVector = this.clientInitializationVector;
this.symEncryptor = this.symEncryptionAlgorithm.CreateEncryptor(this.currentClientEncryptingKey, this.currentClientInitializationVector);
}
}
}
int plainHeaderSize = encoder.Position;
// sequence header
encoder.WriteUInt32(null, this.GetNextSequenceNumber());
encoder.WriteUInt32(null, request.RequestHeader.RequestHandle);
// body
int paddingHeaderSize;
int maxBodySize;
int bodySize;
int paddingSize;
int chunkSize;
if (this.symIsEncrypted)
{
paddingHeaderSize = this.symEncryptionBlockSize > 256 ? 2 : 1;
maxBodySize = ((((int)this.RemoteReceiveBufferSize - plainHeaderSize - this.symSignatureSize - paddingHeaderSize) / this.symEncryptionBlockSize) * this.symEncryptionBlockSize) - SequenceHeaderSize;
if (bodyCount < maxBodySize)
{
bodySize = bodyCount;
paddingSize = (this.symEncryptionBlockSize - ((SequenceHeaderSize + bodySize + paddingHeaderSize + this.symSignatureSize) % this.symEncryptionBlockSize)) % this.symEncryptionBlockSize;
}
else
{
bodySize = maxBodySize;
paddingSize = 0;
}
chunkSize = plainHeaderSize + (((SequenceHeaderSize + bodySize + paddingSize + paddingHeaderSize + this.symSignatureSize) / this.symEncryptionBlockSize) * this.symEncryptionBlockSize);
}
else
{
paddingHeaderSize = 0;
paddingSize = 0;
maxBodySize = (int)this.RemoteReceiveBufferSize - plainHeaderSize - this.symSignatureSize - SequenceHeaderSize;
if (bodyCount < maxBodySize)
{
bodySize = bodyCount;
}
else
{
bodySize = maxBodySize;
}
chunkSize = plainHeaderSize + SequenceHeaderSize + bodySize + this.symSignatureSize;
}
bodyStream.Read(this.sendBuffer, encoder.Position, bodySize);
encoder.Position += bodySize;
bodyCount -= bodySize;
// padding
if (this.symIsEncrypted)
{
var paddingByte = (byte)(paddingSize & 0xFF);
encoder.WriteByte(null, paddingByte);
for (int i = 0; i < paddingSize; i++)
{
encoder.WriteByte(null, paddingByte);
}
if (paddingHeaderSize == 2)
{
var extraPaddingByte = (byte)((paddingSize >> 8) & 0xFF);
encoder.WriteByte(null, extraPaddingByte);
}
}
// update message type and (encrypted) length
var position = encoder.Position;
encoder.Position = 3;
encoder.WriteByte(null, bodyCount > 0 ? (byte)'C' : (byte)'F');
encoder.WriteUInt32(null, (uint)chunkSize);
encoder.Position = position;
// signature
if (this.symIsSigned)
{
byte[] signature = this.symSigner.ComputeHash(this.sendBuffer, 0, position);
if (signature != null)
{
encoder.Write(signature, 0, signature.Length);
}
}
// encrypt
position = encoder.Position;
if (this.symIsEncrypted)
{
using (var symEncryptor = this.symEncryptionAlgorithm.CreateEncryptor(this.currentClientEncryptingKey, this.currentClientInitializationVector))
{
int inputCount = position - plainHeaderSize;
Debug.Assert(inputCount % symEncryptor.InputBlockSize == 0, "Input data is not an even number of encryption blocks.");
symEncryptor.TransformBlock(this.sendBuffer, plainHeaderSize, inputCount, this.sendBuffer, plainHeaderSize);
symEncryptor.TransformFinalBlock(this.sendBuffer, position, 0);
}
}
// pass buffer to transport
await this.SendAsync(this.sendBuffer, 0, position, token).ConfigureAwait(false);
}
finally
{
encoder.Dispose();
}
}
}
finally
{
bodyEncoder.Dispose();
}
}
