UA-.NETStandard/Libraries/Opc.Ua.PubSub/Transport/UdpClientMulticast.cs

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 *
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using System;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using Microsoft.Extensions.Logging;

namespace Opc.Ua.PubSub.Transport
{
    /// <summary>
    /// Represents a specialized <see cref="UdpClient"/> class, configured for Multicast
    /// </summary>
    internal class UdpClientMulticast : UdpClient
    {
        /// <summary>
        /// Initializes a new instance of the <see cref="UdpClient"/> class and binds it to the specified local endpoint
        /// and joins the specified multicast group
        /// </summary>
        /// <param name="localAddress">An <see cref="IPAddress"/> that represents the local address.</param>
        /// <param name="multicastAddress">The multicast <see cref="IPAddress"/> of the group you want to join.</param>
        /// <param name="port">The port.</param>
        /// <param name="telemetry">The telemetry context to use to create obvservability instruments</param>
        /// <exception cref="SocketException">An error occurred when accessing the socket.</exception>
        public UdpClientMulticast(
            IPAddress localAddress,
            IPAddress multicastAddress,
            int port,
            ITelemetryContext telemetry)
        {
            m_logger = telemetry.CreateLogger<UdpClientMulticast>();
            Address = localAddress;
            MulticastAddress = multicastAddress;
            Port = port;

            try
            {
                // this might throw exception on some platforms
                Client.SetSocketOption(
                    SocketOptionLevel.Socket,
                    SocketOptionName.ReuseAddress,
                    true);
            }
            catch (Exception ex)
            {
                m_logger.LogError(ex,
                    "UdpClientMulticast set SetSocketOption resulted in exception");
            }
            try
            {
                // this might throw exception on some platforms
                ExclusiveAddressUse = false;
            }
            catch (Exception ex)
            {
                m_logger.LogError(ex,
                    "UdpClientMulticast set ExclusiveAddressUse = false resulted in exeception");
            }

            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                Client.Bind(new IPEndPoint(IPAddress.Any, port));
                JoinMulticastGroup(multicastAddress);
            }
            else
            {
                Client.Bind(new IPEndPoint(localAddress, port));
                JoinMulticastGroup(multicastAddress, localAddress);
            }

            m_logger.LogInformation(
                "UdpClientMulticast was created for local Address: {Address}:{Port} and multicast address: {Address}.",
                localAddress,
                port,
                multicastAddress);
        }

        /// <summary>
        /// The Local Address
        /// </summary>
        internal IPAddress Address { get; }

        /// <summary>
        /// The Multicast address
        /// </summary>
        internal IPAddress MulticastAddress { get; }

        /// <summary>
        /// The local port
        /// </summary>
        internal int Port { get; }

        private readonly ILogger m_logger;
    }
}