using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Net.NetworkInformation;

using System.Net.Sockets;

using System.Text;

using System.Threading;

using System.Threading.Tasks;

namespace NSmartProxy

{

public static class NetworkUtil

{

private const string PortReleaseGuid = "C086DE94-2C45-4247-81E2-2E5248F5A769";

private static HashSet<int> _usedPorts = new HashSet<int>();

public static bool ReleasePort(int port)

{

return _usedPorts.Remove(port);

}

/// <summary>

/// 查找一个端口

/// </summary>

/// <param name="startPort"></param>

/// <returns></returns>

public static int FindOneAvailableTCPPort(int startPort)

{

return NetworkUtil.FindAvailableTCPPorts(startPort, 1)[0];

}

/// <summary>

/// Check if startPort is available, incrementing and

/// checking again if it's in use until a free port is found

/// </summary>

/// <param name="startPort">The first port to check</param>

/// <returns>The first available port</returns>

public static int[] FindAvailableTCPPorts(int startPort, int PortCount)

{

int[] arrangedPorts = new int[PortCount];

int port = startPort;

bool isAvailable = true;

var mutex = new Mutex(false,

PortReleaseGuid

/*string.Concat("./Global/", PortReleaseGuid)*/);

mutex.WaitOne();

try

{

for (int i = 0; i < PortCount; i++)

{

IPGlobalProperties ipGlobalProperties =

IPGlobalProperties.GetIPGlobalProperties();

IPEndPoint[] endPoints =

ipGlobalProperties.GetActiveTcpListeners();

do

{

if (!isAvailable)

{

port++;

isAvailable = true;

}

if (_usedPorts.Contains(port))

{

isAvailable = false;

continue;

}

foreach (IPEndPoint endPoint in endPoints)

{

if (endPoint.Port != port) continue;

isAvailable = false;

break;

}

} while (!isAvailable && port < IPEndPoint.MaxPort);

if (!isAvailable)

throw new ApplicationException("Not able to find a free TCP port.");

arrangedPorts[i] = port;

_usedPorts.Add(port);

}

return arrangedPorts;

}

finally

{

mutex.ReleaseMutex();

}

}

/// <summary>

/// Check if startPort is available, incrementing and

/// checking again if it's in use until a free port is found

/// </summary>

/// <param name="startPort">The first port to check</param>

/// <returns>The first available port</returns>

public static int FindNextAvailableUDPPort(int startPort)

{

int port = startPort;

bool isAvailable = true;

var mutex = new Mutex(false,

string.Concat("Global/", PortReleaseGuid));

mutex.WaitOne();

try

{

IPGlobalProperties ipGlobalProperties =

IPGlobalProperties.GetIPGlobalProperties();

IPEndPoint[] endPoints =

ipGlobalProperties.GetActiveUdpListeners();

do

{

if (!isAvailable)

{

port++;

isAvailable = true;

}

foreach (IPEndPoint endPoint in endPoints)

{

if (endPoint.Port != port)

continue;

isAvailable = false;

break;

}

} while (!isAvailable && port < IPEndPoint.MaxPort);

if (!isAvailable)

throw new ApplicationException("Not able to find a free TCP port.");

return port;

}

finally

{

mutex.ReleaseMutex();

}

}

public static void SetKeepAlive(this TcpClient tcpClient, out string ErrorMsg)

{

ErrorMsg = "";

// not all platforms support IOControl

//try

//{

// var keepAliveValues = new KeepAliveValues

// {

// OnOff = 1,

// KeepAliveTime = 300000, // 300 seconds in milliseconds

// KeepAliveInterval = 10000 // 10 seconds in milliseconds

// };

// socket.IOControl(IOControlCode.KeepAliveValues, keepAliveValues.ToBytes(), null);

//}

//catch (PlatformNotSupportedException)

//{

// // most platforms should support this call to SetSocketOption, but just in case call it in a try/catch also

// try

// {

// socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);

// }

// catch (PlatformNotSupportedException)

// {

// // ignore PlatformNotSupportedException

// }

//}

//return socket;

//try

//{

tcpClient.Client.IOControl(IOControlCode.KeepAliveValues, GetKeepAlivePkg(1, 1000, 20000), null);

//}

//catch (PlatformNotSupportedException)

//{

// // most platforms should support this call to SetSocketOption, but just in case call it in a try/catch also

// try

// {

// tcpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.KeepAlive, true);

// }

// catch (PlatformNotSupportedException ex)

// {

// //平台不支持

// ErrorMsg = ex.Message;

// }

//}

}

/// <summary>

/// 生成keepalive包用于Socket.IOControl

/// </summary>

/// <param name="onOff">是否開啟 Keep-Alive(開 1/ 關 0)</param>

/// <param name="keepAliveTime">當開啟keep-Alive後經過多久時間(ms)開啟偵測</param>

/// <param name="keepAliveInterval">多久偵測一次</param>

/// <returns></returns>

static byte[] GetKeepAlivePkg(int onOff, int keepAliveTime, int keepAliveInterval)

{

byte[] buffer = new byte[12];

BitConverter.GetBytes(onOff).CopyTo(buffer, 0);

BitConverter.GetBytes(keepAliveTime).CopyTo(buffer, 4);

BitConverter.GetBytes(keepAliveInterval).CopyTo(buffer, 8);

return buffer;

}

}

}