DTLS addition

SharpSnmpLib.Engine/Pipeline/SecureListener.cs

@@ -0,0 +1,298 @@
+using Lextm.SharpSnmpLib.Messaging;
+using Lextm.SharpSnmpLib.Security;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Threading.Tasks;
+
+namespace Lextm.SharpSnmpLib.Pipeline
+{
+    /// <summary>
+    /// Listener class.
+    /// </summary>
+    public sealed class SecureListener
+    {
+        private UserRegistry _users;
+        private bool _disposed;
+
+        /// <summary>
+        /// Error message for non IP v4 OS.
+        /// </summary>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Pv")]
+        public const string ErrorIPv4NotSupported = "cannot use IP v4 as the OS does not support it";
+
+        /// <summary>
+        /// Error message for non IP v6 OS.
+        /// </summary>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1709:IdentifiersShouldBeCasedCorrectly", MessageId = "Pv")]
+        public const string ErrorIPv6NotSupported = "cannot use IP v6 as the OS does not support it";
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="List"/> class.
+        /// </summary>
+        public SecureListener()
+        {
+            Bindings = new List<SecureListenerBinding>();
+        }
+
+        /// <summary>
+        /// Releases unmanaged resources and performs other cleanup operations before the
+        /// <see cref="List"/> is reclaimed by garbage collection.
+        /// </summary>
+        ~SecureListener()
+        {
+            Dispose(false);
+        }
+
+        /// <summary>
+        /// Disposes resources in use.
+        /// </summary>
+        public void Dispose()
+        {
+            Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Releases the unmanaged resources used by the <see cref="T:System.ComponentModel.Component"/> and optionally releases the managed resources.
+        /// </summary>
+        /// <param name="disposing">true to release both managed and unmanaged resources; false to release only unmanaged resources.</param>
+        private void Dispose(bool disposing)
+        {
+            if (_disposed)
+            {
+                return;
+            }
+
+            if (disposing)
+            {
+                if (Bindings != null)
+                {
+                    foreach (var binding in Bindings)
+                    {
+                        binding.Dispose();
+                    }
+
+                    Bindings.Clear();
+                    Bindings = null;
+                }
+            }
+
+            _disposed = true;
+        }
+
+        /// <summary>
+        /// Gets or sets the users.
+        /// </summary>
+        /// <value>The users.</value>
+        public UserRegistry Users
+        {
+            get
+            {
+                if (_disposed)
+                {
+                    throw new ObjectDisposedException(GetType().FullName);
+                }
+
+                return _users ?? (_users = new UserRegistry());
+            }
+
+            set
+            {
+                if (_disposed)
+                {
+                    throw new ObjectDisposedException(GetType().FullName);
+                }
+
+                _users = value;
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether this <see cref="List"/> is active.
+        /// </summary>
+        /// <value><c>true</c> if active; otherwise, <c>false</c>.</value>
+        public bool Active { get; private set; }
+
+        /// <summary>
+        /// Stops this instance.
+        /// </summary>
+        public void Stop()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            if (!Active)
+            {
+                return;
+            }
+
+            foreach (var binding in Bindings)
+            {
+                binding.Stop();
+            }
+
+            Active = false;
+        }
+
+        /// <summary>
+        /// Starts this instance.
+        /// </summary>
+        /// <exception cref="PortInUseException"/>
+        public void Start()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            if (Active)
+            {
+                return;
+            }
+
+            try
+            {
+                foreach (var binding in Bindings)
+                {
+                    binding.Start();
+                }
+            }
+            catch (PortInUseException)
+            {
+                Stop(); // stop all started bindings.
+                throw;
+            }
+
+            Active = true;
+        }
+
+        /// <summary>
+        /// Starts this instance.
+        /// </summary>
+        /// <exception cref="PortInUseException"/>
+        public async Task StartAsync()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            if (Active)
+            {
+                return;
+            }
+
+            try
+            {
+                foreach (var binding in Bindings)
+                {
+                    await binding.StartAsync();
+                }
+            }
+            catch (PortInUseException)
+            {
+                Stop(); // stop all started bindings.
+                throw;
+            }
+
+            Active = true;
+        }
+
+        /// <summary>
+        /// Gets or sets the bindings.
+        /// </summary>
+        /// <value>The bindings.</value>
+        public IList<SecureListenerBinding> Bindings { get; set; }
+
+        /// <summary>
+        /// Occurs when an exception is raised.
+        /// </summary>
+        public event EventHandler<ExceptionRaisedEventArgs> ExceptionRaised;
+
+        /// <summary>
+        /// Occurs when a message is received.
+        /// </summary>
+        public event EventHandler<MessageReceivedEventArgs> MessageReceived;
+
+        /// <summary>
+        /// Adds the binding.
+        /// </summary>
+        /// <param name="endpoint">The endpoint.</param>
+        public void AddBinding(IPEndPoint endpoint)
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            if (Active)
+            {
+                throw new InvalidOperationException("Must be called when Active == false");
+            }
+
+            if (Bindings.Any(existed => existed.Endpoint.Equals(endpoint)))
+            {
+                return;
+            }
+
+            var binding = new SecureListenerBinding(Users, endpoint);
+            binding.ExceptionRaised += (o, args) =>
+            {
+                ExceptionRaised?.Invoke(o, args);
+            };
+            binding.MessageReceived += (o, args) =>
+            {
+                MessageReceived?.Invoke(o, args);
+            };
+            Bindings.Add(binding);
+        }
+
+        /// <summary>
+        /// Removes the binding.
+        /// </summary>
+        /// <param name="endpoint">The endpoint.</param>
+        public void RemoveBinding(IPEndPoint endpoint)
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            if (Active)
+            {
+                throw new InvalidOperationException("Must be called when Active == false");
+            }
+
+            for (var i = 0; i < Bindings.Count; i++)
+            {
+                if (Bindings[i].Endpoint.Equals(endpoint))
+                {
+                    Bindings.RemoveAt(i);
+                }
+            }
+        }
+
+        /// <summary>
+        /// Clears the bindings.
+        /// </summary>
+        public void ClearBindings()
+        {
+            if (_disposed)
+            {
+                throw new ObjectDisposedException(GetType().FullName);
+            }
+
+            foreach (var binding in Bindings)
+            {
+                binding.Stop();
+                binding.Dispose();
+            }
+
+            Bindings.Clear();
+        }
+    }
+}