原文网址： http://www.cnblogs.com/csdev
Networkcomms 是一款C# 语言编写的TCP/UDP通信框架 作者是英国人 以前是收费的 目前作者已经开源 许可是:Apache License v2
开源地址是:https://github.com/MarcFletcher/NetworkComms.Net
/// <summary>
/// A connection object which utilises <see href="http://en.wikipedia.org/wiki/Transmission_Control_Protocol">TCP</see> to communicate between peers.
/// Tcp连接对象 通过TCP协议在端点之间通信
/// </summary>
public sealed partial class TCPConnection : IPConnection
{
#if WINDOWS_PHONE || NETFX_CORE
/// <summary>
/// The windows phone socket corresponding to this connection.
/// </summary>
StreamSocket socket;
#else
/// <summary>
/// The TcpClient corresponding to this connection.
/// 与此连接相关的TcpClient对象
/// </summary>
TcpClient tcpClient;
/// <summary>
/// The networkstream associated with the tcpClient.
/// 与tcpClient相对应额networkstream对象
/// </summary>
Stream connectionStream;
/// <summary>
/// The SSL options associated with this connection.
/// SSL(安全套接层) 相关的参数设置
/// </summary>
public SSLOptions SSLOptions { get; private set; }
#endif
/// <summary>
/// The current incoming data buffer
/// 进入的数据的缓冲区
/// </summary>
byte[] dataBuffer;
/// <summary>
/// TCP connection constructor
/// TCP连接构造器
/// </summary>
#if WINDOWS_PHONE || NETFX_CORE
private TCPConnection(ConnectionInfo connectionInfo, SendReceiveOptions defaultSendReceiveOptions, StreamSocket socket)
#else
private TCPConnection(ConnectionInfo connectionInfo, SendReceiveOptions defaultSendReceiveOptions, TcpClient tcpClient, SSLOptions sslOptions)
#endif
: base(connectionInfo, defaultSendReceiveOptions)
{
if (connectionInfo.ConnectionType != ConnectionType.TCP)
throw new ArgumentException("Provided connectionType must be TCP.", "connectionInfo");
dataBuffer = new byte[NetworkComms.InitialReceiveBufferSizeBytes];
//We don‘t guarantee that the tcpClient has been created yet
//在构造器中 tcpClient对象可能还没有被创建
#if WINDOWS_PHONE || NETFX_CORE
if (socket != null) this.socket = socket;
#else
if (tcpClient != null) this.tcpClient = tcpClient;
this.SSLOptions = sslOptions;
#endif
}
/// <inheritdoc />
/// 创建Tcp连接
protected override void EstablishConnectionSpecific()
{
#if WINDOWS_PHONE || NETFX_CORE
if (socket == null) ConnectSocket();
//For the local endpoint
//本地端点
var localEndPoint = new IPEndPoint(IPAddress.Parse(socket.Information.LocalAddress.CanonicalName.ToString()), int.Parse(socket.Information.LocalPort));
//We should now be able to set the connectionInfo localEndPoint
//此处 可以设置connectionInfo对象的本地端点
NetworkComms.UpdateConnectionReferenceByEndPoint(this, ConnectionInfo.RemoteIPEndPoint, localEndPoint);
ConnectionInfo.UpdateLocalEndPointInfo(localEndPoint);
//Set the outgoing buffer size
//设置发送缓冲区大小
socket.Control.OutboundBufferSizeInBytes = (uint)NetworkComms.SendBufferSizeBytes;
#else
if (tcpClient == null) ConnectSocket();
//We should now be able to set the connectionInfo localEndPoint
//我们现在应该能够设置 connectionInfo对象的本地端点
NetworkComms.UpdateConnectionReferenceByEndPoint(this, ConnectionInfo.RemoteIPEndPoint, (IPEndPoint)tcpClient.Client.LocalEndPoint);
ConnectionInfo.UpdateLocalEndPointInfo((IPEndPoint)tcpClient.Client.LocalEndPoint);
if (SSLOptions.SSLEnabled)
ConfigureSSLStream();
else
//We are going to be using the networkStream quite a bit so we pull out a reference once here
//networkStream类型的网络流 后面会有不少地方需要使用 此处做一个引用
connectionStream = tcpClient.GetStream();
//When we tell the socket/client to close we want it to do so immediately 当我们告诉socket/client关闭时 我们希望其立即关闭
//this.tcpClient.LingerState = new LingerOption(false, 0);
//We need to set the keep alive option otherwise the connection will just die at some random time should we not be using it
//我们需要设定Keep alive选项 以防止连接断开 （后来没有使用）
//NOTE: This did not seem to work reliably so was replaced with the keepAlive packet feature
//注意：设定KeepAlive选项来维护Tcp连接并不可靠 所以后来我们用发送心跳包进行代替
//this.tcpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);
tcpClient.ReceiveBufferSize = NetworkComms.MaxReceiveBufferSizeBytes;
tcpClient.SendBufferSize = NetworkComms.SendBufferSizeBytes;
//This disables the ‘nagle algorithm‘ 禁用 nagle算法
//http://msdn.microsoft.com/en-us/library/system.net.sockets.socket.nodelay.aspx
//Basically we may want to send lots of small packets (<200 bytes) and sometimes those are time critical (e.g. when establishing a connection)
//If we leave this enabled small packets may never be sent until a suitable send buffer length threshold is passed. i.e. BAD
//下面的2个选项设定为true,当Tcp连接上有数据时，立即发送，我符合我们的预期。而不是等待Tcp缓冲池中有足够多的数据才一起发送
tcpClient.NoDelay = true;
tcpClient.Client.NoDelay = true;
#endif
//Start listening for incoming data
//开始监听进来的数据
StartIncomingDataListen();
//If the application layer protocol is enabled we handshake the connection
//如果应用层协议启用 连接进行握手操作
//应用层协议，系统默认为启用
if (ConnectionInfo.ApplicationLayerProtocol == ApplicationLayerProtocolStatus.Enabled)
ConnectionHandshake();
else
{
//If there is no handshake we can now consider the connection established
//如果此处无握手操作 我们可以考虑创建连接
TriggerConnectionEstablishDelegates();
//Trigger any connection setup waits
//触发任何连接建设等待
connectionSetupWait.Set();
}
#if !WINDOWS_PHONE && !NETFX_CORE
//Once the connection has been established we may want to re-enable the ‘nagle algorithm‘ used for reducing network congestion (apparently).
//By default we leave the nagle algorithm disabled because we want the quick through put when sending small packets
//一旦连接建立了，某些情况下我们可能要重新启用“Nagle算法”用于减少网络拥塞。
//默认情况下我们不启用 nagle 算法，启用nagle算法将导致小的数据不能被及时的发送
if (EnableNagleAlgorithmForNewConnections)
{
tcpClient.NoDelay = false;
tcpClient.Client.NoDelay = false;
}
#endif
}
/// <summary>
/// If we were not provided with a tcpClient on creation we need to create one
/// 如果没有tcpClient对象则创建一个
/// </summary>
private void ConnectSocket()
{
try
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Connecting TCP client with " + ConnectionInfo);
bool connectSuccess = true;
#if WINDOWS_PHONE || NETFX_CORE
//We now connect to our target
//我们现在开始连接到我们的目标
socket = new StreamSocket();
socket.Control.NoDelay = !EnableNagleAlgorithmForNewConnections;
CancellationTokenSource cancelAfterTimeoutToken = new CancellationTokenSource(NetworkComms.ConnectionEstablishTimeoutMS);
try
{
if (ConnectionInfo.LocalEndPoint != null && ConnectionInfo.LocalIPEndPoint.Address != IPAddress.IPv6Any && ConnectionInfo.LocalIPEndPoint.Address != IPAddress.Any)
{
var endpointPairForConnection = new Windows.Networking.EndpointPair(new Windows.Networking.HostName(ConnectionInfo.LocalIPEndPoint.Address.ToString()), ConnectionInfo.LocalIPEndPoint.Port.ToString(),
new Windows.Networking.HostName(ConnectionInfo.RemoteIPEndPoint.Address.ToString()), ConnectionInfo.RemoteIPEndPoint.Port.ToString());
var task = socket.ConnectAsync(endpointPairForConnection).AsTask(cancelAfterTimeoutToken.Token);
task.Wait();
}
else
{
var task = socket.ConnectAsync(new Windows.Networking.HostName(ConnectionInfo.RemoteIPEndPoint.Address.ToString()), ConnectionInfo.RemoteIPEndPoint.Port.ToString()).AsTask(cancelAfterTimeoutToken.Token);
task.Wait();
}
}
catch (Exception)
{
socket.Dispose();
connectSuccess = false;
}
#else
//We now connect to our target
//我们现在开始连接到我们的目标
tcpClient = new TcpClient(ConnectionInfo.RemoteEndPoint.AddressFamily);
//Start the connection using the async version
//以异步方式开始连接
//This allows us to choose our own connection establish timeout
//允许设定连接创建超时时间
IAsyncResult ar = tcpClient.BeginConnect(ConnectionInfo.RemoteIPEndPoint.Address, ConnectionInfo.RemoteIPEndPoint.Port, null, null);
WaitHandle connectionWait = ar.AsyncWaitHandle;
try
{
if (!connectionWait.WaitOne(NetworkComms.ConnectionEstablishTimeoutMS, false))
connectSuccess = false;
else
tcpClient.EndConnect(ar);
}
finally
{
connectionWait.Close();
}
#endif
if (!connectSuccess) throw new ConnectionSetupException("Timeout waiting for remoteEndPoint to accept TCP connection.");
}
catch (Exception ex)
{
CloseConnection(true, 17);
throw new ConnectionSetupException("Error during TCP connection establish with destination (" + ConnectionInfo + "). Destination may not be listening or connect timed out. " + ex.ToString());
}
}
/// <inheritdoc />
/// 开始监听进入的数据局
protected override void StartIncomingDataListen()
{
if (!NetworkComms.ConnectionExists(ConnectionInfo.RemoteIPEndPoint, ConnectionInfo.LocalIPEndPoint, ConnectionType.TCP, ConnectionInfo.ApplicationLayerProtocol))
{
CloseConnection(true, 18);
throw new ConnectionSetupException("A connection reference by endPoint should exist before starting an incoming data listener.");
}
#if WINDOWS_PHONE
var stream = socket.InputStream.AsStreamForRead();
stream.BeginRead(dataBuffer, 0, dataBuffer.Length, new AsyncCallback(IncomingTCPPacketHandler), stream);
#elif NETFX_CORE
Task readTask = new Task(async () =>
{
var buffer = Windows.Security.Cryptography.CryptographicBuffer.CreateFromByteArray(dataBuffer);
var readBuffer = await socket.InputStream.ReadAsync(buffer, buffer.Capacity, InputStreamOptions.Partial);
await IncomingTCPPacketHandler(readBuffer);
});
readTask.Start();
#else
lock (SyncRoot)
{
//以同步方式
if (NetworkComms.ConnectionListenModeUseSync)
{
if (incomingDataListenThread == null)
{
//创建一个线程
incomingDataListenThread = new Thread(IncomingTCPDataSyncWorker);
//Incoming data always gets handled in a time critical fashion
//设定数据处理的优先级
incomingDataListenThread.Priority = NetworkComms.timeCriticalThreadPriority;
incomingDataListenThread.Name = "UDP_IncomingDataListener";
incomingDataListenThread.IsBackground = true;
incomingDataListenThread.Start();
}
}
//以异步方式处理
else
{
if (asyncListenStarted) throw new ConnectionSetupException("Async listen already started. Why has this been called twice?.");
asyncListenerInRead = true;
//开始读取连接上的数据
connectionStream.BeginRead(dataBuffer, 0, dataBuffer.Length, new AsyncCallback(IncomingTCPPacketHandler), connectionStream);
asyncListenStarted = true;
}
}
#endif
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Listening for incoming data from " + ConnectionInfo);
}
/// <summary>
/// Asynchronous incoming connection data delegate
/// 以异步的方式处理连接上的数据
/// </summary>
/// <param name="ar">The call back state object</param> 回调状态对象
#if NETFX_CORE
private async Task IncomingTCPPacketHandler(IBuffer buffer)
#else
private void IncomingTCPPacketHandler(IAsyncResult ar)
#endif
{
//Initialised with false so that logic still works in WP8
//初始化状态为false 所以可以在wp8系统下运行
bool dataAvailable = false;
#if !WINDOWS_PHONE && !NETFX_CORE
//Incoming data always gets handled in a timeCritical fashion at this point
//Windows phone and RT platforms do not support thread priorities
//设定数据处理的优先级
//wp 和rt平台不支持线程优先级的设定
Thread.CurrentThread.Priority = NetworkComms.timeCriticalThreadPriority;
#endif
try
{
#if WINDOWS_PHONE
Stream stream = ar.AsyncState as Stream;
totalBytesRead = stream.EndRead(ar) + totalBytesRead;
#elif NETFX_CORE
buffer.CopyTo(0, dataBuffer, totalBytesRead, (int)buffer.Length);
totalBytesRead = (int)buffer.Length + totalBytesRead;
#else
Stream stream;
if (SSLOptions.SSLEnabled)
stream = (SslStream)ar.AsyncState;
else
stream = (NetworkStream)ar.AsyncState;
if (!stream.CanRead)
throw new ObjectDisposedException("Unable to read from stream.");
if (!asyncListenerInRead) throw new InvalidDataException("The asyncListenerInRead flag should be true. 1");
totalBytesRead = stream.EndRead(ar) + totalBytesRead;
asyncListenerInRead = false;
if (SSLOptions.SSLEnabled)
//SSLstream does not have a DataAvailable property. We will just assume false.
//SSLstream (安全套接层)数据流 不支持DataAvailable属性
dataAvailable = false;
else
dataAvailable = ((NetworkStream)stream).DataAvailable;
#endif
if (totalBytesRead > 0)
{
ConnectionInfo.UpdateLastTrafficTime();
//If we have read a single byte which is 0 and we are not expecting other data
//如果只读取到一个字节，内容为0 （猜测这样的单字节一般用于心跳检测）
if (ConnectionInfo.ApplicationLayerProtocol == ApplicationLayerProtocolStatus.Enabled &&
totalBytesRead == 1 && dataBuffer[0] == 0 && packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached == 0)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet removed in IncomingPacketHandler() from " + ConnectionInfo + ". 1");
}
else
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... " + totalBytesRead.ToString() + " bytes added to packetBuilder for " + ConnectionInfo + ". Cached " + packetBuilder.TotalBytesCached.ToString() + " bytes, expecting " + packetBuilder.TotalBytesExpected.ToString() + " bytes.");
//If there is more data to get then add it to the packets lists;
//packetBuilder 数据包创建器
//把读取到的字节添加到"数据包创建器"中
//totalBytesRead 此次读取到的字节数量（int类型） dataBuffer (byte[] 字节数组)
packetBuilder.AddPartialPacket(totalBytesRead, dataBuffer);
#if !WINDOWS_PHONE && !NETFX_CORE
//If we have more data we might as well continue reading synchronously
//In order to deal with data as soon as we think we have sufficient we will leave this loop
//如果我们有更多的数据 继续同步读取
//如果接收到的数据足够多，将离开此循环
//根据networkcomms的机制，第一个字节为数据包包头大小，系统会根据数据包包头大小解析出数据包包头，从数据包包头中读取数据包大小
//这个数据包大小就是packetBuilder中totalBytesExpected，即期望的大小
while (dataAvailable && packetBuilder.TotalBytesCached < packetBuilder.TotalBytesExpected)
{
int bufferOffset = 0;
//We need a buffer for our incoming data
//First we try to reuse a previous buffer
//我们需要为进入的数据准备缓冲区
//首先我们尝试使用以前的缓冲区
if (packetBuilder.TotalPartialPacketCount > 0 && packetBuilder.NumUnusedBytesMostRecentPartialPacket() > 0)
dataBuffer = packetBuilder.RemoveMostRecentPartialPacket(ref bufferOffset);
else
//If we have nothing to reuse we allocate a new buffer. As we are in this loop this can only be a suplementary buffer for THIS packet.
//Therefore we choose a buffer size between the initial amount and the maximum amount based on the expected size
//如果没有可重复使用的缓冲区，我们将新分配一个新的缓冲区
//缓冲区的大小为 数据包创建器.期待的大小 减去 数据包创建器.已收到的大小 （即 数据包长度 减去 已经接收的长度）
{
long additionalBytesNeeded = packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached;
dataBuffer = new byte[Math.Max(Math.Min(additionalBytesNeeded, NetworkComms.MaxReceiveBufferSizeBytes), NetworkComms.InitialReceiveBufferSizeBytes)];
}
totalBytesRead = stream.Read(dataBuffer, bufferOffset, dataBuffer.Length - bufferOffset) + bufferOffset;
if (totalBytesRead > 0)
{
ConnectionInfo.UpdateLastTrafficTime();
//If we have read a single byte which is 0 and we are not expecting other data
//处理单字节数据 一般为心跳消息
if (ConnectionInfo.ApplicationLayerProtocol == ApplicationLayerProtocolStatus.Enabled && totalBytesRead == 1 && dataBuffer[0] == 0 && packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached == 0)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet ignored in IncomingPacketHandler() from " + ConnectionInfo + ". 2");
//LastTrafficTime = DateTime.Now;
}
else
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... " + totalBytesRead.ToString() + " bytes added to packetBuilder for " + ConnectionInfo + ". Cached " + packetBuilder.TotalBytesCached.ToString() + " bytes, expecting " + packetBuilder.TotalBytesExpected.ToString() + " bytes.");
packetBuilder.AddPartialPacket(totalBytesRead, dataBuffer);
if (SSLOptions.SSLEnabled)
//SSLstream does not have a DataAvailable property. We will just assume false.
//SSLstream 没有DataAvailable属性
dataAvailable = false;
else
dataAvailable = ((NetworkStream)stream).DataAvailable;
}
}
else
break;
}
#endif
}
}
if (packetBuilder.TotalBytesCached > 0 && packetBuilder.TotalBytesCached >= packetBuilder.TotalBytesExpected)
{
//Once we think we might have enough data we call the incoming packet handle hand off
//Should we have a complete packet this method will start the appropriate task
//This method will now clear byes from the incoming packets if we have received something complete.
//一旦我们的数据包创建器（packetBuilder)中接收到足够一个数据包的数据，我们将会对数据进行处理
//IncomingPacketHandleHandOff方法处理完packetBuilder中相应的数据后，会把已经处理完的数据删除掉
IncomingPacketHandleHandOff(packetBuilder);
}
if (totalBytesRead == 0 && (!dataAvailable || ConnectionInfo.ConnectionState == ConnectionState.Shutdown))
CloseConnection(false, -2);
else
{
//We need a buffer for our incoming data
//First we try to reuse a previous buffer
//我们需要一个缓冲区来接收数据
//我们先尝试使用以前的缓冲区
if (packetBuilder.TotalPartialPacketCount > 0 && packetBuilder.NumUnusedBytesMostRecentPartialPacket() > 0)
dataBuffer = packetBuilder.RemoveMostRecentPartialPacket(ref totalBytesRead);
else
{
//If we have nothing to reuse we allocate a new buffer
//If packetBuilder.TotalBytesExpected is 0 we know we‘re going to start waiting for a fresh packet. Therefore use the initial buffer size
//如果没有可重复使用的缓冲区，我们将新分配一个新的缓冲区
//如果 数据包创建器 期待的数据大小为0,我们将开始接收一个新的数据包的数据 此时 把缓冲区设置为初始大小
if (packetBuilder.TotalBytesExpected == 0)
dataBuffer = new byte[NetworkComms.InitialReceiveBufferSizeBytes];
else
//Otherwise this can only be a supplementary buffer for THIS packet. Therefore we choose a buffer size between the initial amount and the maximum amount based on the expected size
//如果没有可重复使用的缓冲区，我们将新分配一个新的缓冲区
//缓冲区的大小为 数据包创建器.期待的大小 减去 数据包创建器.已收到的大小 （即 数据包长度 减去 已经接收的长度）
{
long additionalBytesNeeded = packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached;
dataBuffer = new byte[Math.Max(Math.Min(additionalBytesNeeded, NetworkComms.MaxReceiveBufferSizeBytes), NetworkComms.InitialReceiveBufferSizeBytes)];
}
totalBytesRead = 0;
}
#if NETFX_CORE
IBuffer newBuffer = Windows.Security.Cryptography.CryptographicBuffer.CreateFromByteArray(dataBuffer);
var task = IncomingTCPPacketHandler(await socket.InputStream.ReadAsync(newBuffer, newBuffer.Capacity - (uint)totalBytesRead, InputStreamOptions.Partial));
#elif WINDOWS_PHONE
stream.BeginRead(dataBuffer, totalBytesRead, dataBuffer.Length - totalBytesRead, IncomingTCPPacketHandler, stream);
#else
if (asyncListenerInRead) throw new InvalidDataException("The asyncListenerInRead flag should be false. 2");
asyncListenerInRead = true;
stream.BeginRead(dataBuffer, totalBytesRead, dataBuffer.Length - totalBytesRead, IncomingTCPPacketHandler, stream);
#endif
}
}
catch (IOException)
{
CloseConnection(true, 12);
}
catch (ObjectDisposedException)
{
CloseConnection(true, 13);
}
catch (SocketException)
{
CloseConnection(true, 14);
}
catch (InvalidOperationException)
{
CloseConnection(true, 15);
}
catch (Exception ex)
{
LogTools.LogException(ex, "Error_TCPConnectionIncomingPacketHandler");
CloseConnection(true, 31);
}
#if !WINDOWS_PHONE && !NETFX_CORE
Thread.CurrentThread.Priority = ThreadPriority.Normal;
#endif
}
#if !WINDOWS_PHONE && !NETFX_CORE
/// <summary>
/// Synchronous incoming connection data worker
/// 同步处理连接上进入的数据的处理器
/// </summary>
private void IncomingTCPDataSyncWorker()
{
bool dataAvailable = false;
try
{
while (true)
{
if (ConnectionInfo.ConnectionState == ConnectionState.Shutdown)
break;
int bufferOffset = 0;
//We need a buffer for our incoming data
//First we try to reuse a previous buffer
//我们需要为进入的数据准备缓冲区
//首先我们尝试使用以前的缓冲区
if (packetBuilder.TotalPartialPacketCount > 0 && packetBuilder.NumUnusedBytesMostRecentPartialPacket() > 0)
dataBuffer = packetBuilder.RemoveMostRecentPartialPacket(ref bufferOffset);
else
{
//If we have nothing to reuse we allocate a new buffer
//If packetBuilder.TotalBytesExpected is 0 we know we‘re going to start waiting for a fresh packet. Therefore use the initial buffer size
//如果没有可重复使用的缓冲区，我们将新分配一个新的缓冲区
//如果 数据包创建器 期待的数据大小为0,我们将开始接收一个新的数据包的数据 此时 把缓冲区设置为初始大小
if (packetBuilder.TotalBytesExpected == 0)
dataBuffer = new byte[NetworkComms.InitialReceiveBufferSizeBytes];
else
//Otherwise this can only be a supplementary buffer for THIS packet. Therefore we choose a buffer size between the initial amount and the maximum amount based on the expected size
//如果没有可重复使用的缓冲区，我们将新分配一个新的缓冲区
//缓冲区的大小为 数据包创建器.期待的大小 减去 数据包创建器.已收到的大小 （即 数据包长度 减去 已经接收的长度）
{
long additionalBytesNeeded = packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached;
dataBuffer = new byte[Math.Max(Math.Min(additionalBytesNeeded, NetworkComms.MaxReceiveBufferSizeBytes), NetworkComms.InitialReceiveBufferSizeBytes)];
}
}
//We block here until there is data to read
//When we read data we read until method returns or we fill the buffer length
//程序将会阻塞 直到读取到数据
//我们读取数据 直到方法返回或者读取到缓冲区大小的数据
totalBytesRead = connectionStream.Read(dataBuffer, bufferOffset, dataBuffer.Length - bufferOffset) + bufferOffset;
//Check to see if there is more data ready to be read
//检查是否还有数据需要读取
if (SSLOptions.SSLEnabled)
//SSLstream does not have a DataAvailable property. We will just assume false.
//SSLStream没有DataAvailable属性
dataAvailable = false;
else
dataAvailable = ((NetworkStream)connectionStream).DataAvailable;
//If we read any data it gets handed off to the packetBuilder
//如果我们读取到数据，交给packetBuilder处理
if (totalBytesRead > 0)
{
ConnectionInfo.UpdateLastTrafficTime();
//If we have read a single byte which is 0 and we are not expecting other data
//处理单字节 内容为0 的数据 （一般为心跳检测)
if (ConnectionInfo.ApplicationLayerProtocol == ApplicationLayerProtocolStatus.Enabled && totalBytesRead == 1 && dataBuffer[0] == 0 && packetBuilder.TotalBytesExpected - packetBuilder.TotalBytesCached == 0)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... null packet removed in IncomingDataSyncWorker() from "+ConnectionInfo+".");
}
else
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace(" ... " + totalBytesRead.ToString() + " bytes added to packetBuilder for " + ConnectionInfo + ". Cached " + packetBuilder.TotalBytesCached.ToString() + " bytes, expecting " + packetBuilder.TotalBytesExpected.ToString() + " bytes.");
//添加数据到 数据包创建器中
packetBuilder.AddPartialPacket(totalBytesRead, dataBuffer);
}
}
else if (totalBytesRead == 0 && (!dataAvailable || ConnectionInfo.ConnectionState == ConnectionState.Shutdown))
{
//If we read 0 bytes and there is no data available we should be shutting down
//如果我们没有读取到数据 应该关闭连接
CloseConnection(false, -10);
break;
}
//If we have read some data and we have more or equal what was expected we attempt a data hand off
//如果我们读取到足够的数据（可以解析出一个数据包），对数据进行处理
if (packetBuilder.TotalBytesCached > 0 && packetBuilder.TotalBytesCached >= packetBuilder.TotalBytesExpected)
IncomingPacketHandleHandOff(packetBuilder);
}
}
//On any error here we close the connection
//捕捉异常 关闭连接
catch (NullReferenceException)
{
CloseConnection(true, 7);
}
catch (IOException)
{
CloseConnection(true, 8);
}
catch (ObjectDisposedException)
{
CloseConnection(true, 9);
}
catch (SocketException)
{
CloseConnection(true, 10);
}
catch (InvalidOperationException)
{
CloseConnection(true, 11);
}
catch (Exception ex)
{
LogTools.LogException(ex, "Error_TCPConnectionIncomingPacketHandler");
CloseConnection(true, 39);
}
//Clear the listen thread object because the thread is about to end
//清除监听线程 因为线程将关闭
incomingDataListenThread = null;
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Trace("Incoming data listen thread ending for " + ConnectionInfo);
}
/// <summary>
/// Configure the SSL stream from this connection
/// 配置当期连接上 SSL 数据流
/// </summary>
private void ConfigureSSLStream()
{
try
{
if (ConnectionInfo.ServerSide)
{
connectionStream = new SslStream(tcpClient.GetStream(), false,
new RemoteCertificateValidationCallback(CertificateValidationCallback),
new LocalCertificateSelectionCallback(CertificateSelectionCallback));
((SslStream)connectionStream).AuthenticateAsServer(SSLOptions.Certificate, SSLOptions.RequireMutualAuthentication, SslProtocols.Default, false);
}
else
{
X509CertificateCollection certs = new X509CertificateCollection();
if (SSLOptions.Certificate != null) certs.Add(SSLOptions.Certificate);
//If we have a certificate set we use that to authenticate
connectionStream = new SslStream(tcpClient.GetStream(), false,
new RemoteCertificateValidationCallback(CertificateValidationCallback),
new LocalCertificateSelectionCallback(CertificateSelectionCallback));
((SslStream)connectionStream).AuthenticateAsClient(SSLOptions.CertificateName, certs, SslProtocols.Default, false);
}
}
catch (AuthenticationException ex)
{
throw new ConnectionSetupException("SSL authentication failed. Please check configuration and try again.", ex);
}
SSLOptions.Authenticated = true;
}
/// <summary>
/// Callback used to determine if the provided certificate should be accepted
/// 回调方法 用于确定是否应该接受所提供的证书
/// </summary>
/// <param name="sender"></param>
/// <param name="certificate"></param>
/// <param name="chain"></param>
/// <param name="sslPolicyErrors"></param>
/// <returns></returns>
private bool CertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
if (sslPolicyErrors == SslPolicyErrors.None)
return true;
else if (sslPolicyErrors == SslPolicyErrors.RemoteCertificateNotAvailable && ConnectionInfo.ServerSide)
//If the client did not provide a remote certificate it may well be because
//we were not requesting one
//如果客户没有提供远程认证它很可能是因为我们没有要求
return !SSLOptions.RequireMutualAuthentication;
else if (SSLOptions.AllowSelfSignedCertificate && //If we allows self signed certificates we make sure the errors are correct 如果我们允许自签名认证 我们确定这些错误是正确的
chain.ChainStatus.Length == 1 && //Only a single chain error 只是一个单一的链错误
sslPolicyErrors == SslPolicyErrors.RemoteCertificateChainErrors &&
chain.ChainStatus[0].Status == X509ChainStatusFlags.UntrustedRoot)
{
//If we have a local certificate we compare them 如果我们有一个本地的证书 我们比较他们
if (SSLOptions.Certificate != null)
return certificate.Equals(SSLOptions.Certificate);
else
return true;
}
else
return false;
}
/// <summary>
/// Certificate selection callback
/// 证书选择 回调方法
/// </summary>
/// <param name="sender"></param>
/// <param name="targetHost"></param>
/// <param name="localCertificates"></param>
/// <param name="remoteCertificate"></param>
/// <param name="acceptableIssuers"></param>
/// <returns></returns>
private X509Certificate CertificateSelectionCallback(object sender, string targetHost, X509CertificateCollection localCertificates,
X509Certificate remoteCertificate, string[] acceptableIssuers)
{
return SSLOptions.Certificate;
}
#endif
/// <inheritdoc />
protected override void CloseConnectionSpecific(bool closeDueToError, int logLocation = 0)
{
#if WINDOWS_PHONE || NETFX_CORE
//Try to close the socket
try
{
socket.Dispose();
}
catch (Exception)
{
}
#else
//The following attempts to correctly close the connection
//Try to close the networkStream first
//以下试图正确的关闭连接
//首先尝试关闭网络流
try
{
if (connectionStream != null) connectionStream.Close();
}
catch (Exception)
{
}
finally
{
connectionStream = null;
}
//Try to close the tcpClient
//尝试关闭tcpClient对象
try
{
if (tcpClient.Client!=null)
{
tcpClient.Client.Disconnect(false);
#if !ANDROID
//Throws uncatchable exception in android
//在安卓系统中抛出不可捕捉的异常
tcpClient.Client.Close();
#endif
}
}
catch (Exception)
{
}
//Try to close the tcpClient
//尝试关闭连接
try
{
#if !ANDROID
//Throws uncatchable exception in android
//在安卓系统中抛出不可捕捉的异常
tcpClient.Close();
#endif
}
catch (Exception)
{
}
#endif
}
/// <inheritdoc />
protected override double[] SendStreams(StreamTools.StreamSendWrapper[] streamsToSend, double maxSendTimePerKB, long totalBytesToSend)
{
double[] timings = new double[streamsToSend.Length];
Stream sendingStream;
#if WINDOWS_PHONE || NETFX_CORE
sendingStream = socket.OutputStream.AsStreamForWrite();
#else
sendingStream = connectionStream;
#endif
for(int i=0; i<streamsToSend.Length; i++)
{
if (streamsToSend[i].Length > 0)
{
//Write each stream
//写入数据流
timings[i] = streamsToSend[i].ThreadSafeStream.CopyTo(sendingStream, streamsToSend[i].Start, streamsToSend[i].Length, NetworkComms.SendBufferSizeBytes, maxSendTimePerKB, MinSendTimeoutMS);
streamsToSend[i].ThreadSafeStream.Dispose();
}
else
timings[i] = 0;
}
#if WINDOWS_PHONE || NETFX_CORE
sendingStream.Flush();
#endif
#if !WINDOWS_PHONE && !NETFX_CORE
if (!tcpClient.Connected)
{
if (NetworkComms.LoggingEnabled) NetworkComms.Logger.Error("TCPClient is not marked as connected after write to networkStream. Possibly indicates a dropped connection.");
throw new CommunicationException("TCPClient is not marked as connected after write to networkStream. Possibly indicates a dropped connection.");
}
#endif
return timings;
}
}
时间： 2024-10-11 22:23:54