/// <summary> /// Creates a TCP connection to server /// </summary> /// <param name="remoteHostName">The remote hostname.</param> /// <param name="remotePort">The remote port.</param> /// <param name="httpVersion">The http version to use.</param> /// <param name="isHttps">Is this a HTTPS request.</param> /// <param name="sslProtocol">The SSL protocol.</param> /// <param name="applicationProtocols">The list of HTTPS application level protocol to negotiate if needed.</param> /// <param name="isConnect">Is this a CONNECT request.</param> /// <param name="proxyServer">The current ProxyServer instance.</param> /// <param name="sessionArgs">The http session.</param> /// <param name="upStreamEndPoint">The local upstream endpoint to make request via.</param> /// <param name="externalProxy">The external proxy to make request via.</param> /// <param name="cacheKey">The connection cache key</param> /// <param name="prefetch">if set to <c>true</c> [prefetch].</param> /// <param name="cancellationToken">The cancellation token for this async task.</param> /// <returns></returns> private async Task <TcpServerConnection?> createServerConnection(string remoteHostName, int remotePort, Version httpVersion, bool isHttps, SslProtocols sslProtocol, List <SslApplicationProtocol>?applicationProtocols, bool isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint?upStreamEndPoint, IExternalProxy?externalProxy, string cacheKey, bool prefetch, CancellationToken cancellationToken) { // deny connection to proxy end points to avoid infinite connection loop. if (Server.ProxyEndPoints.Any(x => x.Port == remotePort) && NetworkHelper.IsLocalIpAddress(remoteHostName)) { throw new Exception($"A client is making HTTP request to one of the listening ports of this proxy {remoteHostName}:{remotePort}"); } if (externalProxy != null) { if (Server.ProxyEndPoints.Any(x => x.Port == externalProxy.Port) && NetworkHelper.IsLocalIpAddress(externalProxy.HostName)) { throw new Exception($"A client is making HTTP request via external proxy to one of the listening ports of this proxy {remoteHostName}:{remotePort}"); } } if (isHttps && sslProtocol == SslProtocols.None) { sslProtocol = proxyServer.SupportedSslProtocols; } bool useUpstreamProxy1 = false; // check if external proxy is set for HTTP/HTTPS if (externalProxy != null && !(externalProxy.HostName == remoteHostName && externalProxy.Port == remotePort)) { useUpstreamProxy1 = true; // check if we need to ByPass if (externalProxy.BypassLocalhost && NetworkHelper.IsLocalIpAddress(remoteHostName)) { useUpstreamProxy1 = false; } } if (!useUpstreamProxy1) { externalProxy = null; } Socket? tcpServerSocket = null; HttpServerStream?stream = null; SslApplicationProtocol negotiatedApplicationProtocol = default; bool retry = true; var enabledSslProtocols = sslProtocol; retry: try { bool socks = externalProxy != null && externalProxy.ProxyType != ExternalProxyType.Http; string hostname = remoteHostName; int port = remotePort; if (externalProxy != null) { hostname = externalProxy.HostName; port = externalProxy.Port; } var ipAddresses = await Dns.GetHostAddressesAsync(hostname); if (upStreamEndPoint?.AddressFamily == AddressFamily.InterNetworkV6 && !ipAddresses.Any(ip => ip.AddressFamily == AddressFamily.InterNetworkV6)) { var result = await ExtendNetworkService.LookupClient.GetHostEntryAsync(hostname); ipAddresses = result.AddressList; } if (upStreamEndPoint?.AddressFamily == AddressFamily.InterNetworkV6 && ipAddresses.Any(t => t.AddressFamily == AddressFamily.InterNetwork)) { if (ExtendNetworkService.ExcludeResuceUrls.Contains(hostname)) { ipAddresses = ipAddresses.Where(t => t.AddressFamily == AddressFamily.InterNetworkV6).ToArray(); } else { ipAddresses = ipAddresses.Where(t => t.AddressFamily == AddressFamily.InterNetworkV6 && !ipAddresses.Any(v4 => v4.AddressFamily == AddressFamily.InterNetwork && v4.ToString().Equals(t.MapToIPv4().ToString()))).ToArray(); } } if (ipAddresses == null || ipAddresses.Length == 0) { if (prefetch) { return(null); } throw new Exception($"Could not resolve the hostname {hostname}"); } if (sessionArgs != null) { sessionArgs.TimeLine["Dns Resolved"] = DateTime.UtcNow; } Array.Sort(ipAddresses, (x, y) => x.AddressFamily.CompareTo(y.AddressFamily)); Exception?lastException = null; for (int i = 0; i < ipAddresses.Length; i++) { try { var ipAddress = ipAddresses[i]; var addressFamily = upStreamEndPoint?.AddressFamily ?? ipAddress.AddressFamily; if (socks) { var proxySocket = new ProxySocket.ProxySocket(addressFamily, SocketType.Stream, ProtocolType.Tcp); proxySocket.ProxyType = externalProxy !.ProxyType == ExternalProxyType.Socks4 ? ProxyTypes.Socks4 : ProxyTypes.Socks5; proxySocket.ProxyEndPoint = new IPEndPoint(ipAddress, port); if (!string.IsNullOrEmpty(externalProxy?.UserName) && externalProxy?.Password != null) { proxySocket.ProxyUser = externalProxy.UserName; proxySocket.ProxyPass = externalProxy.Password; } tcpServerSocket = proxySocket; } else { tcpServerSocket = new Socket(addressFamily, SocketType.Stream, ProtocolType.Tcp); } if (upStreamEndPoint != null) { tcpServerSocket.Bind(upStreamEndPoint); } tcpServerSocket.NoDelay = proxyServer.NoDelay; tcpServerSocket.ReceiveTimeout = proxyServer.ConnectionTimeOutSeconds * 1000; tcpServerSocket.SendTimeout = proxyServer.ConnectionTimeOutSeconds * 1000; tcpServerSocket.LingerState = new LingerOption(true, proxyServer.TcpTimeWaitSeconds); //if (addressFamily == AddressFamily.InterNetworkV6) //{ // tcpServerSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.IPv6Only, true); //} //else if (proxyServer.ReuseSocket && RunTime.IsSocketReuseAvailable) { tcpServerSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true); } Task connectTask; if (socks) { if (externalProxy !.ProxyDnsRequests) { connectTask = ProxySocketConnectionTaskFactory.CreateTask((ProxySocket.ProxySocket)tcpServerSocket, remoteHostName, remotePort); } else { // todo: resolve only once when the SOCKS proxy has multiple addresses (and the first address fails) var remoteIpAddresses = await Dns.GetHostAddressesAsync(remoteHostName); if (remoteIpAddresses == null || remoteIpAddresses.Length == 0) { throw new Exception($"Could not resolve the SOCKS remote hostname {remoteHostName}"); } // todo: use the 2nd, 3rd... remote addresses when first fails connectTask = ProxySocketConnectionTaskFactory.CreateTask((ProxySocket.ProxySocket)tcpServerSocket, remoteIpAddresses[0], remotePort); } } else { connectTask = SocketConnectionTaskFactory.CreateTask(tcpServerSocket, ipAddress, port); } await Task.WhenAny(connectTask, Task.Delay(proxyServer.ConnectTimeOutSeconds * 1000, cancellationToken)); if (!connectTask.IsCompleted || !tcpServerSocket.Connected) { // here we can just do some cleanup and let the loop continue since // we will either get a connection or wind up with a null tcpClient // which will throw try { connectTask.Dispose(); } catch { // ignore } try { #if NET45 tcpServerSocket?.Close(); #else tcpServerSocket?.Dispose(); #endif tcpServerSocket = null; } catch { // ignore } continue; } break; } catch (Exception e) { // dispose the current TcpClient and try the next address lastException = e; #if NET45 tcpServerSocket?.Close(); #else tcpServerSocket?.Dispose(); #endif tcpServerSocket = null; } }
/// <summary> /// Creates a TCP connection to server /// </summary> /// <param name="remoteHostName">The remote hostname.</param> /// <param name="remotePort">The remote port.</param> /// <param name="httpVersion">The http version to use.</param> /// <param name="isHttps">Is this a HTTPS request.</param> /// <param name="sslProtocol">The SSL protocol.</param> /// <param name="applicationProtocols">The list of HTTPS application level protocol to negotiate if needed.</param> /// <param name="isConnect">Is this a CONNECT request.</param> /// <param name="proxyServer">The current ProxyServer instance.</param> /// <param name="sessionArgs">The http session.</param> /// <param name="upStreamEndPoint">The local upstream endpoint to make request via.</param> /// <param name="externalProxy">The external proxy to make request via.</param> /// <param name="cacheKey">The connection cache key</param> /// <param name="cancellationToken">The cancellation token for this async task.</param> /// <returns></returns> private async Task <TcpServerConnection> createServerConnection(string remoteHostName, int remotePort, Version httpVersion, bool isHttps, SslProtocols sslProtocol, List <SslApplicationProtocol>?applicationProtocols, bool isConnect, ProxyServer proxyServer, SessionEventArgsBase sessionArgs, IPEndPoint?upStreamEndPoint, IExternalProxy?externalProxy, string cacheKey, CancellationToken cancellationToken) { // deny connection to proxy end points to avoid infinite connection loop. if (Server.ProxyEndPoints.Any(x => x.Port == remotePort) && NetworkHelper.IsLocalIpAddress(remoteHostName)) { throw new Exception($"A client is making HTTP request to one of the listening ports of this proxy {remoteHostName}:{remotePort}"); } if (externalProxy != null) { if (Server.ProxyEndPoints.Any(x => x.Port == externalProxy.Port) && NetworkHelper.IsLocalIpAddress(externalProxy.HostName)) { throw new Exception($"A client is making HTTP request via external proxy to one of the listening ports of this proxy {remoteHostName}:{remotePort}"); } } if (isHttps && sslProtocol == SslProtocols.None) { sslProtocol = proxyServer.SupportedSslProtocols; } bool useUpstreamProxy1 = false; // check if external proxy is set for HTTP/HTTPS if (externalProxy != null && !(externalProxy.HostName == remoteHostName && externalProxy.Port == remotePort)) { useUpstreamProxy1 = true; // check if we need to ByPass if (externalProxy.BypassLocalhost && NetworkHelper.IsLocalIpAddress(remoteHostName)) { useUpstreamProxy1 = false; } } if (!useUpstreamProxy1) { externalProxy = null; } Socket? tcpServerSocket = null; HttpServerStream?stream = null; SslApplicationProtocol negotiatedApplicationProtocol = default; bool retry = true; var enabledSslProtocols = sslProtocol; retry: try { bool socks = externalProxy != null && externalProxy.ProxyType != ExternalProxyType.Http; string hostname = remoteHostName; int port = remotePort; if (externalProxy != null && externalProxy.ProxyType == ExternalProxyType.Http) { hostname = externalProxy.HostName; port = externalProxy.Port; } var ipAddresses = await Dns.GetHostAddressesAsync(hostname); if (ipAddresses == null || ipAddresses.Length == 0) { throw new Exception($"Could not resolve the hostname {hostname}"); } if (sessionArgs != null) { sessionArgs.TimeLine["Dns Resolved"] = DateTime.UtcNow; } Array.Sort(ipAddresses, (x, y) => x.AddressFamily.CompareTo(y.AddressFamily)); Exception?lastException = null; for (int i = 0; i < ipAddresses.Length; i++) { try { var ipAddress = ipAddresses[i]; var addressFamily = upStreamEndPoint?.AddressFamily ?? ipAddress.AddressFamily; if (socks) { var proxySocket = new ProxySocket.ProxySocket(addressFamily, SocketType.Stream, ProtocolType.Tcp); proxySocket.ProxyType = externalProxy !.ProxyType == ExternalProxyType.Socks4 ? ProxyTypes.Socks4 : ProxyTypes.Socks5; var proxyIpAddresses = await Dns.GetHostAddressesAsync(externalProxy.HostName); proxySocket.ProxyEndPoint = new IPEndPoint(proxyIpAddresses[0], externalProxy.Port); if (!string.IsNullOrEmpty(externalProxy.UserName) && externalProxy.Password != null) { proxySocket.ProxyUser = externalProxy.UserName; proxySocket.ProxyPass = externalProxy.Password; } tcpServerSocket = proxySocket; } else { tcpServerSocket = new Socket(addressFamily, SocketType.Stream, ProtocolType.Tcp); } if (upStreamEndPoint != null) { tcpServerSocket.Bind(upStreamEndPoint); } tcpServerSocket.NoDelay = proxyServer.NoDelay; tcpServerSocket.ReceiveTimeout = proxyServer.ConnectionTimeOutSeconds * 1000; tcpServerSocket.SendTimeout = proxyServer.ConnectionTimeOutSeconds * 1000; tcpServerSocket.LingerState = new LingerOption(true, proxyServer.TcpTimeWaitSeconds); if (proxyServer.ReuseSocket && RunTime.IsSocketReuseAvailable) { tcpServerSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true); } var connectTask = socks ? ProxySocketConnectionTaskFactory.CreateTask((ProxySocket.ProxySocket)tcpServerSocket, ipAddress, port) : SocketConnectionTaskFactory.CreateTask(tcpServerSocket, ipAddress, port); await Task.WhenAny(connectTask, Task.Delay(proxyServer.ConnectTimeOutSeconds * 1000, cancellationToken)); if (!connectTask.IsCompleted || !tcpServerSocket.Connected) { // here we can just do some cleanup and let the loop continue since // we will either get a connection or wind up with a null tcpClient // which will throw try { connectTask.Dispose(); } catch { // ignore } try { #if NET45 tcpServerSocket?.Close(); #else tcpServerSocket?.Dispose(); #endif tcpServerSocket = null; } catch { // ignore } continue; } break; } catch (Exception e) { // dispose the current TcpClient and try the next address lastException = e; #if NET45 tcpServerSocket?.Close(); #else tcpServerSocket?.Dispose(); #endif tcpServerSocket = null; } } if (tcpServerSocket == null) { if (sessionArgs != null && proxyServer.CustomUpStreamProxyFailureFunc != null) { var newUpstreamProxy = await proxyServer.CustomUpStreamProxyFailureFunc(sessionArgs); if (newUpstreamProxy != null) { sessionArgs.CustomUpStreamProxyUsed = newUpstreamProxy; sessionArgs.TimeLine["Retrying Upstream Proxy Connection"] = DateTime.UtcNow; return(await createServerConnection(remoteHostName, remotePort, httpVersion, isHttps, sslProtocol, applicationProtocols, isConnect, proxyServer, sessionArgs, upStreamEndPoint, externalProxy, cacheKey, cancellationToken)); } } throw new Exception($"Could not establish connection to {hostname}", lastException); } if (sessionArgs != null) { sessionArgs.TimeLine["Connection Established"] = DateTime.UtcNow; } await proxyServer.InvokeServerConnectionCreateEvent(tcpServerSocket); stream = new HttpServerStream(new NetworkStream(tcpServerSocket, true), proxyServer.BufferPool, cancellationToken); if ((externalProxy != null && externalProxy.ProxyType == ExternalProxyType.Http) && (isConnect || isHttps)) { var authority = $"{remoteHostName}:{remotePort}".GetByteString(); var connectRequest = new ConnectRequest(authority) { IsHttps = isHttps, RequestUriString8 = authority, HttpVersion = httpVersion }; connectRequest.Headers.AddHeader(KnownHeaders.Connection, KnownHeaders.ConnectionKeepAlive); if (!string.IsNullOrEmpty(externalProxy.UserName) && externalProxy.Password != null) { connectRequest.Headers.AddHeader(HttpHeader.ProxyConnectionKeepAlive); connectRequest.Headers.AddHeader(HttpHeader.GetProxyAuthorizationHeader(externalProxy.UserName, externalProxy.Password)); } await stream.WriteRequestAsync(connectRequest, cancellationToken); var httpStatus = await stream.ReadResponseStatus(cancellationToken); if (httpStatus.StatusCode != 200 && !httpStatus.Description.EqualsIgnoreCase("OK") && !httpStatus.Description.EqualsIgnoreCase("Connection Established")) { throw new Exception("Upstream proxy failed to create a secure tunnel"); } await stream.ReadAndIgnoreAllLinesAsync(cancellationToken); } if (isHttps) { var sslStream = new SslStream(stream, false, (sender, certificate, chain, sslPolicyErrors) => proxyServer.ValidateServerCertificate(sender, sessionArgs, certificate, chain, sslPolicyErrors), (sender, targetHost, localCertificates, remoteCertificate, acceptableIssuers) => proxyServer.SelectClientCertificate(sender, sessionArgs, targetHost, localCertificates, remoteCertificate, acceptableIssuers)); stream = new HttpServerStream(sslStream, proxyServer.BufferPool, cancellationToken); var options = new SslClientAuthenticationOptions { ApplicationProtocols = applicationProtocols, TargetHost = remoteHostName, ClientCertificates = null !, EnabledSslProtocols = enabledSslProtocols, CertificateRevocationCheckMode = proxyServer.CheckCertificateRevocation }; await sslStream.AuthenticateAsClientAsync(options, cancellationToken); #if NETSTANDARD2_1 negotiatedApplicationProtocol = sslStream.NegotiatedApplicationProtocol; #endif if (sessionArgs != null) { sessionArgs.TimeLine["HTTPS Established"] = DateTime.UtcNow; } } } catch (IOException ex) when(ex.HResult == unchecked ((int)0x80131620) && retry && enabledSslProtocols >= SslProtocols.Tls11) { stream?.Dispose(); tcpServerSocket?.Close(); enabledSslProtocols = SslProtocols.Tls; retry = false; goto retry; } catch (Exception) { stream?.Dispose(); tcpServerSocket?.Close(); throw; } return(new TcpServerConnection(proxyServer, tcpServerSocket, stream, remoteHostName, remotePort, isHttps, negotiatedApplicationProtocol, httpVersion, externalProxy, upStreamEndPoint, cacheKey)); }