Get active TCP connection states and statistics

TcpStats.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net.NetworkInformation

public static class TcpStats
{
	private static int _stateLength = Enum.GetNames(typeof(TcpState)).Length;
	private static int _longestState = Enum.GetNames(typeof(TcpState)).Max(s => s.Length);
	
	public static string GetTcpStates(bool detailed)
	{
		var builder = new StringBuilder();
		IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
		
		var states = new Dictionary<TcpState, int>(_stateLength);

		foreach (var connection in properties.GetActiveTcpConnections())
		{
			if (detailed)
			{
				builder.AppendLine($"{connection.State.ToString().PadRight(_longestState)}: {connection.RemoteEndPoint.Address}:{connection.RemoteEndPoint.Port}");
			}
				
			if (states.TryGetValue(connection.State, out var count))
			{
				states[connection.State] = ++count;
			}
			else 
			{
				states.Add(connection.State, 1);	
			}
		}

		builder.AppendLine("TCP states:");
		foreach (var kv in states)
		{
			var key = kv.Key.ToString();
			builder.AppendLine($"  {key}: {new string(' ', _longestState - key.Length)}\t{kv.Value}");
		}
		
		return builder.ToString();
	}
	
	public static string GetTcpStats(NetworkInterfaceComponent version)
	{
		var builder = new StringBuilder();
		IPGlobalProperties properties = IPGlobalProperties.GetIPGlobalProperties();
		TcpStatistics tcpstat = null;
		
		switch (version)
		{
			case NetworkInterfaceComponent.IPv4:
				tcpstat = properties.GetTcpIPv4Statistics();
				builder.AppendLine("TCP/IPv4 Statistics:");
				break;
			case NetworkInterfaceComponent.IPv6:
				tcpstat = properties.GetTcpIPv6Statistics();
				builder.AppendLine("TCP/IPv6 Statistics:");
				break;
			default:
				throw new ArgumentException("version");
		}
		builder
			.AppendLine($"  Minimum Transmission Timeout: {tcpstat.MinimumTransmissionTimeout}")
			.AppendLine($"  Maximum Transmission Timeout: {tcpstat.MaximumTransmissionTimeout}")
			.AppendLine("  Connection Data:")
			.AppendLine($"      Current:         {tcpstat.CurrentConnections}")
			.AppendLine($"      Cumulative:      {tcpstat.CumulativeConnections}")
			.AppendLine($"      Initiated:       {tcpstat.ConnectionsInitiated}")
			.AppendLine($"      Accepted:        {tcpstat.ConnectionsAccepted}")
			.AppendLine($"      Failed Attempts: {tcpstat.FailedConnectionAttempts}")
			.AppendLine($"      Reset:           {tcpstat.ResetConnections}")
			.AppendLine("  Segment Data:")
			.AppendLine($"      Received:        {tcpstat.SegmentsReceived}")
			.AppendLine($"      Sent:            {tcpstat.SegmentsSent}")
			.AppendLine($"      Retransmitted:   {tcpstat.SegmentsResent}");

		return builder.ToString();
	}
}