Remove unneeded feature flags and pass cancellationToken to DNS request (#1290)

* remove unneeded feature flags

FEATURE_SOCKET_EAP and FEATURE_DNS_SYNC were set for all
frameworks, so unneeded. The other feature flags were
only used in elif of FEATURE_SOCKET_EAP and FEATURE_DNS_SYNC,
so also unneeded.

* pass cancellationToken to Dns.GetHostAddressesAsync

* Removed DnsAbstractions

Author: mus65

src/Renci.SshNet/Abstractions/DnsAbstraction.cs

@@ -59,7 +59,6 @@ public static async Task ConnectAsync(Socket socket, IPEndPoint remoteEndpoint,
 
         private static void ConnectCore(Socket socket, IPEndPoint remoteEndpoint, TimeSpan connectTimeout, bool ownsSocket)
         {
-#if FEATURE_SOCKET_EAP
             var connectCompleted = new ManualResetEvent(initialState: false);
             var args = new SocketAsyncEventArgs
                 {
@@ -113,19 +112,6 @@ private static void ConnectCore(Socket socket, IPEndPoint remoteEndpoint, TimeSp
 
             // dispose SocketAsyncEventArgs
             args.Dispose();
-#elif FEATURE_SOCKET_APM
-            var connectResult = socket.BeginConnect(remoteEndpoint, null, null);
-            if (!connectResult.AsyncWaitHandle.WaitOne(connectTimeout, false))
-                throw new SshOperationTimeoutException(string.Format(CultureInfo.InvariantCulture,
-                    "Connection failed to establish within {0:F0} milliseconds.", connectTimeout.TotalMilliseconds));
-            socket.EndConnect(connectResult);
-#elif FEATURE_SOCKET_TAP
-            if (!socket.ConnectAsync(remoteEndpoint).Wait(connectTimeout))
-                throw new SshOperationTimeoutException(string.Format(CultureInfo.InvariantCulture,
-                    "Connection failed to establish within {0:F0} milliseconds.", connectTimeout.TotalMilliseconds));
-#else
-            #error Connecting to a remote endpoint is not implemented.
-#endif
         }
 
         public static void ClearReadBuffer(Socket socket)
@@ -391,12 +377,10 @@ public static bool IsErrorResumable(SocketError socketError)
 #pragma warning restore IDE0010 // Add missing cases
         }
 
-#if FEATURE_SOCKET_EAP
         private static void ConnectCompleted(object sender, SocketAsyncEventArgs e)
         {
             var eventWaitHandle = (ManualResetEvent) e.UserToken;
             _ = eventWaitHandle?.Set();
         }
-#endif // FEATURE_SOCKET_EAP
     }
 }

src/Renci.SshNet/Abstractions/SocketAbstraction.cs

@@ -38,7 +38,7 @@ protected ConnectorBase(ISocketFactory socketFactory)
         /// <exception cref="SocketException">An error occurred trying to establish the connection.</exception>
         protected Socket SocketConnect(string host, int port, TimeSpan timeout)
         {
-            var ipAddress = DnsAbstraction.GetHostAddresses(host)[0];
+            var ipAddress = Dns.GetHostAddresses(host)[0];
             var ep = new IPEndPoint(ipAddress, port);
 
             DiagnosticAbstraction.Log(string.Format("Initiating connection to '{0}:{1}'.", host, port));
@@ -73,7 +73,12 @@ protected async Task<Socket> SocketConnectAsync(string host, int port, Cancellat
         {
             cancellationToken.ThrowIfCancellationRequested();
 
-            var ipAddress = (await DnsAbstraction.GetHostAddressesAsync(host).ConfigureAwait(false))[0];
+#if NET6_0_OR_GREATER
+            var ipAddress = (await Dns.GetHostAddressesAsync(host, cancellationToken).ConfigureAwait(false))[0];
+#else
+            var ipAddress = (await Dns.GetHostAddressesAsync(host).ConfigureAwait(false))[0];
+#endif
+
             var ep = new IPEndPoint(ipAddress, port);
 
             DiagnosticAbstraction.Log(string.Format("Initiating connection to '{0}:{1}'.", host, port));

src/Renci.SshNet/Connection/ConnectorBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 using System.Net.Sockets;
 using System.Text;
 
@@ -108,7 +109,7 @@ private static byte[] CreateSocks4ConnectionRequest(string hostname, ushort port
 
         private static byte[] GetSocks4DestinationAddress(string hostname)
         {
-            var addresses = DnsAbstraction.GetHostAddresses(hostname);
+            var addresses = Dns.GetHostAddresses(hostname);
 
             for (var i = 0; i < addresses.Length; i++)
             {

src/Renci.SshNet/Connection/Socks4Connector.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Net;
 using System.Net.Sockets;
 
 using Renci.SshNet.Abstractions;
@@ -243,7 +244,7 @@ private static byte[] CreateSocks5ConnectionRequest(string hostname, ushort port
 
         private static byte[] GetSocks5DestinationAddress(string hostname, out byte addressType)
         {
-            var ip = DnsAbstraction.GetHostAddresses(hostname)[0];
+            var ip = Dns.GetHostAddresses(hostname)[0];
 
             byte[] address;
 

src/Renci.SshNet/Connection/Socks5Connector.cs

@@ -159,7 +159,7 @@ private void InternalStart()
             var ip = IPAddress.Any;
             if (!string.IsNullOrEmpty(BoundHost))
             {
-                ip = DnsAbstraction.GetHostAddresses(BoundHost)[0];
+                ip = Dns.GetHostAddresses(BoundHost)[0];
             }
 
             var ep = new IPEndPoint(ip, (int) BoundPort);

src/Renci.SshNet/ForwardedPortDynamic.cs

@@ -198,7 +198,7 @@ protected override void Dispose(bool disposing)
 
         private void InternalStart()
         {
-            var addr = DnsAbstraction.GetHostAddresses(BoundHost)[0];
+            var addr = Dns.GetHostAddresses(BoundHost)[0];
             var ep = new IPEndPoint(addr, (int) BoundPort);
 
             _listener = new Socket(ep.AddressFamily, SocketType.Stream, ProtocolType.Tcp) { NoDelay = true };

src/Renci.SshNet/ForwardedPortLocal.cs

@@ -125,9 +125,9 @@ public ForwardedPortRemote(uint boundPort, string host, uint port)
         /// <param name="host">The host.</param>
         /// <param name="port">The port.</param>
         public ForwardedPortRemote(string boundHost, uint boundPort, string host, uint port)
-            : this(DnsAbstraction.GetHostAddresses(boundHost)[0],
+            : this(Dns.GetHostAddresses(boundHost)[0],
                    boundPort,
-                   DnsAbstraction.GetHostAddresses(host)[0],
+                   Dns.GetHostAddresses(host)[0],
                    port)
         {
         }

src/Renci.SshNet/ForwardedPortRemote.cs

@@ -6,7 +6,7 @@
   </PropertyGroup>
 
   <PropertyGroup Condition=" '$(TargetFramework)' == 'net462' ">
-    <DefineConstants>$(DefineConstants);FEATURE_BINARY_SERIALIZATION;FEATURE_SOCKET_EAP;FEATURE_SOCKET_APM;FEATURE_DNS_SYNC;FEATURE_HASH_RIPEMD160_CREATE;FEATURE_HMAC_RIPEMD160</DefineConstants>
+    <DefineConstants>$(DefineConstants);FEATURE_BINARY_SERIALIZATION;FEATURE_HASH_RIPEMD160_CREATE;FEATURE_HMAC_RIPEMD160</DefineConstants>
   </PropertyGroup>
 
   <ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netstandard2.1' or '$(TargetFramework)' == 'net6.0' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' ">
@@ -16,8 +16,4 @@
   <ItemGroup Condition=" '$(TargetFramework)' == 'net462' or '$(TargetFramework)' == 'netstandard2.0' ">
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="1.0.0" />
   </ItemGroup>
-
-  <PropertyGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' or '$(TargetFramework)' == 'netstandard2.1' or '$(TargetFramework)' == 'net6.0' or '$(TargetFramework)' == 'net7.0' or '$(TargetFramework)' == 'net8.0' ">
-    <DefineConstants>$(DefineConstants);FEATURE_SOCKET_TAP;FEATURE_SOCKET_APM;FEATURE_SOCKET_EAP;FEATURE_DNS_SYNC;FEATURE_DNS_APM;FEATURE_DNS_TAP</DefineConstants>
-  </PropertyGroup>
 </Project>