/// <summary>
/// Constructor.
/// </summary>
/// <param name="options">The SMTP server options.</param>
/// <param name="tcpClient">The TCP client to operate the session on.</param>
internal SmtpSession(ISmtpServerOptions options, TcpClient tcpClient)
{
_options = options;
_tcpClient = tcpClient;
_context = new SmtpSessionContext(tcpClient);
_stateMachine = new SmtpStateMachine(options, _context);
}
/// <summary>
/// Listen for SMTP traffic on the given endpoint.
/// </summary>
/// <param name="endpointDefinition">The definition of the endpoint to listen on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which performs the operation.</returns>
async Task ListenAsync(IEndpointDefinition endpointDefinition, CancellationToken cancellationToken)
{
// The listener can be stopped either by the caller cancelling the CancellationToken used when starting the server, or when calling
// the shutdown method. The Shutdown method will stop the listeners and allow any active sessions to finish gracefully.
var cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(_shutdownTokenSource.Token, cancellationToken);
using var endpointListener = _endpointListenerFactory.CreateListener(endpointDefinition);
while (cancellationTokenSource.Token.IsCancellationRequested == false)
{
var sessionContext = new SmtpSessionContext(_serviceProvider, _options, endpointDefinition);
try
{
// wait for a client connection
sessionContext.Pipe = await GetPipeAsync(endpointListener, sessionContext, cancellationTokenSource.Token).ConfigureAwait(false);
}
catch (OperationCanceledException) { }
catch (Exception ex)
{
OnSessionFaulted(new SessionFaultedEventArgs(sessionContext, ex));
continue;
}
_sessions.Run(sessionContext, cancellationTokenSource.Token);
}
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
internal async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var retryCount = _maxRetries;
while (retryCount-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
var text = await context.Text.ReadLineAsync(cancellationToken).ConfigureAwait(false);
SmtpCommand command;
SmtpResponse errorResponse;
if (TryAccept(context, text, out command, out errorResponse) == false)
{
var response = new SmtpResponse(errorResponse.ReplyCode, $"{errorResponse.Message}, {retryCount} retry(ies) remaining.");
await context.Text.ReplyAsync(response, cancellationToken);
continue;
}
// the command was a normal command so we can reset the retry count
retryCount = _maxRetries;
await ExecuteAsync(command, context, cancellationToken).ConfigureAwait(false);
}
}
/// <summary>
/// Listen for SMTP traffic on the given endpoint.
/// </summary>
/// <param name="endpointDefinition">The definition of the endpoint to listen on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which performs the operation.</returns>
async Task ListenAsync(IEndpointDefinition endpointDefinition, CancellationToken cancellationToken)
{
using (var endpointListener = _options.EndpointListenerFactory.CreateListener(endpointDefinition))
{
while (_shutdownTokenSource.Token.IsCancellationRequested == false && cancellationToken.IsCancellationRequested == false)
{
var sessionContext = new SmtpSessionContext(_options, endpointDefinition);
try
{
await ListenAsync(sessionContext, endpointListener, cancellationToken);
}
catch (OperationCanceledException) when(_shutdownTokenSource.Token.IsCancellationRequested == false)
{
if (sessionContext.NetworkClient != null)
{
OnSessionCancelled(new SessionEventArgs(sessionContext));
}
}
catch (OperationCanceledException) { }
catch (Exception ex)
{
OnSessionFaulted(new SessionFaultedEventArgs(sessionContext, ex));
}
}
}
}
/// <summary>
/// Read the command input.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The input that was received from the client.</returns>
async Task <IReadOnlyList <ArraySegment <byte> > > ReadCommandInputAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var timeout = new CancellationTokenSource(_context.ServerOptions.CommandWaitTimeout);
var cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(timeout.Token, cancellationToken);
try
{
return(await context.NetworkClient.ReadLineAsync(cancellationTokenSource.Token).ConfigureAwait(false));
}
catch (OperationCanceledException)
{
if (timeout.IsCancellationRequested)
{
await context.NetworkClient.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "Timeout whilst waiting for input."), cancellationToken).ConfigureAwait(false);
return(null);
}
await context.NetworkClient.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), CancellationToken.None).ConfigureAwait(false);
return(null);
}
finally
{
timeout.Dispose();
cancellationTokenSource.Dispose();
}
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var retries = _options.MaxRetryCount;
while (retries-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
var text = await context.Client.ReadLineAsync(cancellationToken).ReturnOnAnyThread();
if (TryAccept(context, text, out SmtpCommand command, out SmtpResponse response))
{
try
{
await ExecuteAsync(command, context, cancellationToken).ReturnOnAnyThread();
retries = _options.MaxRetryCount;
continue;
}
catch (SmtpResponseException responseException)
{
context.IsQuitRequested = responseException.IsQuitRequested;
response = responseException.Response;
}
}
await context.Client.ReplyAsync(CreateErrorResponse(response, retries), cancellationToken);
}
}
/// <summary>
/// Listen for SMTP traffic on the given endpoint.
/// </summary>
/// <param name="endpointDefinition">The definition of the endpoint to listen on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which performs the operation.</returns>
async Task ListenAsync(IEndpointDefinition endpointDefinition, CancellationToken cancellationToken)
{
// The listener can be stopped either by the caller cancelling the CancellationToken used when starting the server, or when calling
// the shutdown method. The Shutdown method will stop the listeners and allow any active sessions to finish gracefully.
var cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(_shutdownTokenSource.Token, cancellationToken);
using var endpointListener = _endpointListenerFactory.CreateListener(endpointDefinition);
while (cancellationTokenSource.Token.IsCancellationRequested == false)
{
var sessionContext = new SmtpSessionContext(_serviceProvider, _options, endpointDefinition);
try
{
// wait for a client connection
sessionContext.Pipe = await endpointListener.GetPipeAsync(sessionContext, cancellationTokenSource.Token).ConfigureAwait(false);
cancellationTokenSource.Token.ThrowIfCancellationRequested();
if (sessionContext.EndpointDefinition.IsSecure && _options.ServerCertificate != null)
{
await sessionContext.Pipe.UpgradeAsync(_options.ServerCertificate, _options.SupportedSslProtocols, cancellationToken).ConfigureAwait(false);
cancellationToken.ThrowIfCancellationRequested();
}
_sessions.Run(sessionContext, cancellationTokenSource.Token);
}
catch (OperationCanceledException) { }
}
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
// The PROXY protocol requires that the receiver must wait for the
// proxy command to be fully received before it starts processing the
// session. Since the receiver is expected to speak first in SMTP,
// i.e. sending the greeting on connect, we wait for the proxy
// command to be consumed and processed before speaking to the
// remote client.
if (!_context.ServerOptions.Proxy)
{
await OutputGreetingAsync(cancellationToken).ReturnOnAnyThread();
}
if (_context.ServerOptions.Proxy)
{
await IngestProxyAsync(context, cancellationToken).ReturnOnAnyThread();
}
var retries = _context.ServerOptions.MaxRetryCount;
while (retries-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
var text = await ReadCommandInputAsync(context, cancellationToken);
if (text == null)
{
return;
}
if (TryMake(context, text, out var command, out var response))
{
try
{
if (await ExecuteAsync(command, context, cancellationToken).ReturnOnAnyThread())
{
_stateMachine.Transition(context);
}
retries = _context.ServerOptions.MaxRetryCount;
continue;
}
catch (SmtpResponseException responseException)
{
context.IsQuitRequested = responseException.IsQuitRequested;
response = responseException.Response;
}
catch (OperationCanceledException)
{
await context.NetworkClient.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), cancellationToken);
return;
}
}
await context.NetworkClient.ReplyAsync(CreateErrorResponse(response, retries), cancellationToken);
}
}
/// <summary>
/// Execute the command.
/// </summary>
/// <param name="command">The command to execute.</param>
/// <param name="context">The execution context to operate on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
static async Task <bool> ExecuteAsync(SmtpCommand command, SmtpSessionContext context, CancellationToken cancellationToken)
{
context.RaiseCommandExecuting(command);
var result = await command.ExecuteAsync(context, cancellationToken);
context.RaiseCommandExecuted(command);
return(result);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="options">The SMTP server options.</param>
/// <param name="tcpClient">The TCP client to operate the session on.</param>
/// <param name="stateMachine">The SMTP state machine.</param>
internal SmtpSession(ISmtpServerOptions options, TcpClient tcpClient, SmtpStateMachine stateMachine)
{
_options = options;
_tcpClient = tcpClient;
Context = new SmtpSessionContext(new SmtpTransaction(), stateMachine, tcpClient.Client.RemoteEndPoint)
{
Text = new NetworkTextStream(tcpClient.GetStream())
};
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="options">The SMTP server options.</param>
/// <param name="tcpClient">The TCP client to operate the session on.</param>
/// <param name="stateMachine">The SMTP state machine.</param>
internal SmtpSession(ISmtpServerOptions options, TcpClient tcpClient, SmtpStateMachine stateMachine)
{
_options = options;
_tcpClient = tcpClient;
_stateMachine = stateMachine;
Context = new SmtpSessionContext(new SmtpTransaction(), stateMachine, tcpClient.Client.RemoteEndPoint)
{
Text = new NetworkTextStream(tcpClient)
};
}
/// <summary>
/// Listen for SMTP traffic on the given endpoint.
/// </summary>
/// <param name="endpointDefinition">The definition of the endpoint to listen on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which performs the operation.</returns>
async Task ListenAsync(IEndpointDefinition endpointDefinition, CancellationToken cancellationToken)
{
// keep track of the running tasks for disposal
var sessions = new ConcurrentDictionary <SmtpSession, SmtpSession>();
using (var endpointListener = _options.EndpointListenerFactory.CreateListener(endpointDefinition))
{
while (cancellationToken.IsCancellationRequested == false)
{
var sessionContext = new SmtpSessionContext(_options, endpointDefinition);
// wait for a client connection
var stream = await endpointListener.GetStreamAsync(sessionContext, cancellationToken).ConfigureAwait(false);
cancellationToken.ThrowIfCancellationRequested();
sessionContext.NetworkClient = new NetworkClient(stream, _options.NetworkBufferSize, _options.NetworkBufferReadTimeout);
if (endpointDefinition.IsSecure && _options.ServerCertificate != null)
{
await sessionContext.NetworkClient.UpgradeAsync(_options.ServerCertificate, _options.SupportedSslProtocols, cancellationToken);
cancellationToken.ThrowIfCancellationRequested();
}
// create a new session to handle the connection
var session = new SmtpSession(sessionContext);
sessions.TryAdd(session, session);
OnSessionCreated(new SessionEventArgs(sessionContext));
session.Run(cancellationToken);
#pragma warning disable 4014
session.Task
.ContinueWith(t =>
{
if (sessions.TryRemove(session, out var s))
{
sessionContext.NetworkClient.Dispose();
}
OnSessionCompleted(new SessionEventArgs(sessionContext));
},
cancellationToken);
#pragma warning restore 4014
}
// the server has been cancelled, wait for the tasks to complete
await Task.WhenAll(sessions.Keys.Select(s => s.Task)).ConfigureAwait(false);
}
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var retries = _context.ServerOptions.MaxRetryCount;
while (retries-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
var text = await ReadCommandInputAsync(context, cancellationToken).ConfigureAwait(false);
if (text == null)
{
return;
}
if (TryMake(context, text, out var command, out var response) == false)
{
await context.NetworkClient.ReplyAsync(CreateErrorResponse(response, retries), cancellationToken).ConfigureAwait(false);
continue;
}
try
{
if (await ExecuteAsync(command, context, cancellationToken).ConfigureAwait(false))
{
_stateMachine.Transition(context);
}
retries = _context.ServerOptions.MaxRetryCount;
}
catch (SmtpResponseException responseException) when(responseException.IsQuitRequested)
{
await context.NetworkClient.ReplyAsync(responseException.Response, cancellationToken).ConfigureAwait(false);
return;
}
catch (SmtpResponseException responseException)
{
response = CreateErrorResponse(responseException.Response, retries);
await context.NetworkClient.ReplyAsync(response, cancellationToken).ConfigureAwait(false);
}
catch (OperationCanceledException)
{
await context.NetworkClient.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), cancellationToken).ConfigureAwait(false);
return;
}
}
}
internal void Run(SmtpSessionContext sessionContext, CancellationToken cancellationToken)
{
var handle = new SmtpSessionHandle(new SmtpSession(sessionContext), sessionContext);
Add(handle);
handle.CompletionTask = RunAsync(handle, cancellationToken);
// ReSharper disable once MethodSupportsCancellation
handle.CompletionTask.ContinueWith(
task =>
{
Remove(handle);
});
}
/// <summary>
/// Read the command input.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>The input that was received from the client.</returns>
async Task <IReadOnlyList <ArraySegment <byte> > > ReadCommandInputAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
try
{
return(await context.Client.ReadLineAsync(_options.CommandWaitTimeout, cancellationToken).ReturnOnAnyThread());
}
catch (TimeoutException)
{
await context.Client.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "Timeout whilst waiting for input."), cancellationToken);
}
catch (OperationCanceledException)
{
await context.Client.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), cancellationToken);
}
return(null);
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var retries = _context.ServerOptions.MaxRetryCount;
while (retries-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
try
{
var command = await ReadCommandAsync(context, cancellationToken).ConfigureAwait(false);
if (command == null)
{
return;
}
if (_stateMachine.TryAccept(command, out var errorResponse) == false)
{
throw new SmtpResponseException(errorResponse);
}
if (await ExecuteAsync(command, context, cancellationToken).ConfigureAwait(false))
{
_stateMachine.Transition(context);
}
retries = _context.ServerOptions.MaxRetryCount;
}
catch (SmtpResponseException responseException) when(responseException.IsQuitRequested)
{
await context.Pipe.Output.WriteReplyAsync(responseException.Response, cancellationToken).ConfigureAwait(false);
context.IsQuitRequested = true;
}
catch (SmtpResponseException responseException)
{
var response = CreateErrorResponse(responseException.Response, retries);
await context.Pipe.Output.WriteReplyAsync(response, cancellationToken).ConfigureAwait(false);
}
catch (OperationCanceledException)
{
await context.Pipe.Output.WriteReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), CancellationToken.None).ConfigureAwait(false);
}
}
}
async Task IngestProxyAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var text = await ReadCommandInputAsync(context, cancellationToken);
if (TryMake(context, text, out SmtpCommand command, out SmtpResponse response))
{
if (await ExecuteAsync(command, context, cancellationToken).ReturnOnAnyThread())
{
await OutputGreetingAsync(cancellationToken).ReturnOnAnyThread();
await _context.NetworkClient.FlushAsync(cancellationToken).ReturnOnAnyThread();
}
else
{
await _context.NetworkClient.FlushAsync(cancellationToken).ReturnOnAnyThread();
}
}
}
/// <summary>
/// Execute the command handler against the specified session context.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
async Task ExecuteAsync(SmtpSessionContext context, CancellationToken cancellationToken)
{
var retries = _options.MaxRetryCount;
while (retries-- > 0 && context.IsQuitRequested == false && cancellationToken.IsCancellationRequested == false)
{
var text = await ReadCommandInputAsync(context, cancellationToken);
if (text == null)
{
return;
}
if (TryAccept(context, text, out SmtpCommand command, out SmtpResponse response))
{
try
{
await ExecuteAsync(command, context, cancellationToken).ReturnOnAnyThread();
retries = _options.MaxRetryCount;
continue;
}
catch (SmtpResponseException responseException)
{
context.IsQuitRequested = responseException.IsQuitRequested;
response = responseException.Response;
}
catch (OperationCanceledException)
{
await context.Client.ReplyAsync(new SmtpResponse(SmtpReplyCode.ServiceClosingTransmissionChannel, "The session has be cancelled."), cancellationToken);
return;
}
}
await context.Client.ReplyAsync(CreateErrorResponse(response, retries), cancellationToken);
}
}
async Task ListenAsync(SmtpSessionContext sessionContext, IEndpointListener endpointListener, CancellationToken cancellationToken)
{
// The listener can be stopped either by the caller cancelling the CancellationToken used when starting the server, or when calling
// the shutdown method. The Shutdown method will stop the listeners and allow any active sessions to finish gracefully.
var cancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(_shutdownTokenSource.Token, cancellationToken);
// wait for a client connection
var stream = await endpointListener.GetStreamAsync(sessionContext, cancellationTokenSource.Token).ConfigureAwait(false);
cancellationTokenSource.Token.ThrowIfCancellationRequested();
sessionContext.NetworkClient = new NetworkClient(stream, _options.NetworkBufferSize);
if (sessionContext.EndpointDefinition.IsSecure && _options.ServerCertificate != null)
{
await sessionContext.NetworkClient.Stream.UpgradeAsync(_options.ServerCertificate, _options.SupportedSslProtocols, cancellationToken).ConfigureAwait(false);
cancellationToken.ThrowIfCancellationRequested();
}
_sessions.Run(sessionContext, cancellationToken);
}
public void Run(SmtpSessionContext sessionContext, CancellationToken cancellationToken)
{
var session = new SmtpSession(sessionContext);
Add(session);
_smtpServer.OnSessionCreated(new SessionEventArgs(sessionContext));
session.Run(
exception =>
{
Remove(session);
sessionContext.NetworkClient.Dispose();
if (exception != null)
{
_smtpServer.OnSessionFaulted(new SessionFaultedEventArgs(sessionContext, exception));
}
_smtpServer.OnSessionCompleted(new SessionEventArgs(sessionContext));
},
cancellationToken);
}
/// <summary>
/// Advances the enumerator to the next command in the stream.
/// </summary>
/// <param name="context">The session context to execute the command handler against.</param>
/// <param name="text">The text to return the commands from.</param>
/// <param name="command">The command that was found.</param>
/// <param name="errorResponse">The error response that indicates why a command could not be accepted.</param>
/// <returns>true if a valid command was found, false if not.</returns>
bool TryAccept(SmtpSessionContext context, string text, out SmtpCommand command, out SmtpResponse errorResponse)
{
return(context.StateMachine.TryAccept(new TokenEnumerator(new StringTokenReader(text)), out command, out errorResponse));
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="context">The session context.</param>
internal SmtpSession(SmtpSessionContext context)
{
_context = context;
_stateMachine = new SmtpStateMachine(_context);
}
/// <summary>
/// Execute the command.
/// </summary>
/// <param name="command">The command to execute.</param>
/// <param name="context">The execution context to operate on.</param>
/// <param name="cancellationToken">The cancellation token.</param>
/// <returns>A task which asynchronously performs the execution.</returns>
Task <bool> ExecuteAsync(SmtpCommand command, SmtpSessionContext context, CancellationToken cancellationToken)
{
context.RaiseCommandExecuting(command);
return(command.ExecuteAsync(context, cancellationToken));
}
/// <summary>
/// Advances the enumerator to the next command in the stream.
/// </summary>
/// <param name="context">The session context to use when making session based transitions.</param>
/// <param name="segments">The list of array segments to read the command from.</param>
/// <param name="command">The command that was found.</param>
/// <param name="errorResponse">The error response that indicates why a command could not be accepted.</param>
/// <returns>true if a valid command was found, false if not.</returns>
bool TryMake(SmtpSessionContext context, IReadOnlyList <ArraySegment <byte> > segments, out SmtpCommand command, out SmtpResponse errorResponse)
{
var tokenEnumerator = new TokenEnumerator(new ByteArrayTokenReader(segments));
return(_stateMachine.TryMake(context, tokenEnumerator, out command, out errorResponse));
}
public SmtpSessionHandle(SmtpSession session, SmtpSessionContext sessionContext)
{
Session = session;
SessionContext = sessionContext;
}
async Task <ISecurableDuplexPipe> GetPipeAsync(IEndpointListener endpointListener, SmtpSessionContext sessionContext, CancellationToken cancellationToken)
{
var pipe = await endpointListener.GetPipeAsync(sessionContext, cancellationToken).ConfigureAwait(false);
try
{
cancellationToken.ThrowIfCancellationRequested();
if (sessionContext.EndpointDefinition.IsSecure && _options.ServerCertificate != null)
{
await pipe.UpgradeAsync(_options.ServerCertificate, _options.SupportedSslProtocols, cancellationToken).ConfigureAwait(false);
cancellationToken.ThrowIfCancellationRequested();
}
}
catch
{
pipe.Dispose();
throw;
}
return(pipe);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="context">The session context.</param>
internal SmtpSession(SmtpSessionContext context)
{
_context = context;
_stateMachine = new SmtpStateMachine(_context);
_commandFactory = context.ServiceProvider.GetServiceOrDefault <ISmtpCommandFactory>(new SmtpCommandFactory());
}