private void Data(SMTPContext context)
{
context.WriteLine(MESSAGE_START_DATA);
SMTPMessage message = context.Message;
IPEndPoint clientEndPoint = (IPEndPoint)context.Socket.RemoteEndPoint;
StringBuilder header = new StringBuilder();
header.Append(String.Format("Received: from {0} ({0} [{1}])", context.ClientDomain, clientEndPoint.Address));
header.Append("\r\n");
header.Append(String.Format(" by {0} (Eric Daugherty's C# Email Server)", domain));
header.Append("\r\n");
header.Append(" " + System.DateTime.Now);
header.Append("\r\n");
message.AddData(header.ToString());
String line = context.ReadLine();
while (!line.Equals("."))
{
message.AddData(line);
message.AddData("\r\n");
line = context.ReadLine();
}
// Spool the message
messageSpool.SpoolMessage(message);
context.WriteLine(MESSAGE_OK);
// Reset the connection.
context.Reset();
}
/// <summary>
/// Handle the RCPT TO:<address> command.
/// </summary>
private void Rcpt(SMTPContext context, string argument)
{
if (context.LastCommand == COMMAND_MAIL || context.LastCommand == COMMAND_RCPT)
{
string address = ParseAddress(argument);
if (address != null)
{
try
{
EmailAddress emailAddress = new EmailAddress(address);
// Check to make sure we want to accept this message.
if (recipientFilter.AcceptRecipient(context, emailAddress))
{
context.Message.AddToAddress(emailAddress);
context.LastCommand = COMMAND_RCPT;
context.WriteLine(MESSAGE_OK);
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: RcptTo address: {1} accepted.", context.ConnectionId, address));
}
}
else
{
context.WriteLine(MESSAGE_UNKNOWN_USER);
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: RcptTo address: {1} rejected. Did not pass Address Filter.", context.ConnectionId, address));
}
}
}
catch (InvalidEmailAddressException)
{
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: RcptTo argument: {1} rejected. Should be from:<*****@*****.**>", context.ConnectionId, argument));
}
context.WriteLine(MESSAGE_INVALID_ADDRESS);
}
}
else
{
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: RcptTo argument: {1} rejected. Should be from:<*****@*****.**>", context.ConnectionId, argument));
}
context.WriteLine(MESSAGE_INVALID_ADDRESS);
}
}
else
{
context.WriteLine(MESSAGE_INVALID_COMMAND_ORDER);
}
}
/// <summary>
/// Reset the connection state.
/// </summary>
private void Rset(SMTPContext context)
{
if (context.LastCommand != -1)
{
// Dump the message and reset the context.
context.Reset();
context.WriteLine(MESSAGE_OK);
}
else
{
context.WriteLine(MESSAGE_INVALID_COMMAND_ORDER);
}
}
/// <summary>
/// Handle the MAIL FROM:<address> command.
/// </summary>
private void Mail(SMTPContext context, string argument)
{
bool addressValid = false;
if (context.LastCommand == COMMAND_HELO)
{
string address = ParseAddress(argument);
if (address != null)
{
try
{
EmailAddress emailAddress = new EmailAddress(address);
context.Message.FromAddress = emailAddress;
context.LastCommand = COMMAND_MAIL;
addressValid = true;
context.WriteLine(MESSAGE_OK);
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: MailFrom address: {1} accepted.", context.ConnectionId, address));
}
}
catch (InvalidEmailAddressException)
{
// This is fine, just fall through.
}
}
// If the address is invalid, inform the client.
if (!addressValid)
{
if (log.IsDebugEnabled)
{
log.Debug(String.Format("Connection {0}: MailFrom argument: {1} rejected. Should be from:<*****@*****.**>", context.ConnectionId, argument));
}
context.WriteLine(MESSAGE_INVALID_ADDRESS);
}
}
else
{
context.WriteLine(MESSAGE_INVALID_COMMAND_ORDER);
}
}
/// <summary>
/// Handles the HELO command.
/// </summary>
private void Helo(SMTPContext context, String[] inputs)
{
if (context.LastCommand == -1)
{
if (inputs.Length == 2)
{
context.ClientDomain = inputs[1];
context.LastCommand = COMMAND_HELO;
context.WriteLine(HeloResponse);
}
else
{
context.WriteLine(MESSAGE_INVALID_ARGUMENT_COUNT);
}
}
else
{
context.WriteLine(MESSAGE_INVALID_COMMAND_ORDER);
}
}
/// <summary>
/// ProcessConnection handles a connected TCP Client
/// and performs all necessary interaction with this
/// client to comply with RFC821. This method is thread
/// safe.
/// </summary>
public void ProcessConnection(Socket socket)
{
long currentConnectionId = 0;
// Really only need to lock on the long, but that is not
// allowed. Is there a better way to do this?
lock (this)
{
currentConnectionId = connectionId++;
}
SMTPContext context = new SMTPContext(currentConnectionId, socket);
try
{
SendWelcomeMessage(context);
ProcessCommands(context);
}
catch (Exception exception)
{
log.Error(String.Format("Connection {0}: Error: {1}", context.ConnectionId, exception), exception);
}
}
/// <summary>
/// Accepts only local email.
/// </summary>
/// <param name='context'>The SMTPContext</param>
/// <param name='recipient'>TODO - add parameter description</param>
public virtual bool AcceptRecipient(SMTPContext context, EmailAddress recipient)
{
return(domain.Equals(recipient.Domain));
}
/// <summary>
/// Handles the command input from the client. This
/// message returns when the client issues the quit command.
/// </summary>
private void ProcessCommands(SMTPContext context)
{
bool isRunning = true;
String inputLine;
// Loop until the client quits.
while (isRunning)
{
try
{
inputLine = context.ReadLine();
if (inputLine == null)
{
isRunning = false;
context.Close();
continue;
}
log.Debug("ProcessCommands Read: " + inputLine);
String[] inputs = inputLine.Split(" ".ToCharArray());
switch (inputs[0].ToLower())
{
case "helo":
Helo(context, inputs);
break;
case "rset":
Rset(context);
break;
case "noop":
context.WriteLine(MESSAGE_OK);
break;
case "quit":
isRunning = false;
context.WriteLine(MESSAGE_GOODBYE);
context.Close();
break;
case "mail":
if (inputs[1].ToLower().StartsWith("from"))
{
Mail(context, inputLine.Substring(inputLine.IndexOf(" ")));
break;
}
context.WriteLine(MESSAGE_UNKNOWN_COMMAND);
break;
case "rcpt":
if (inputs[1].ToLower().StartsWith("to"))
{
Rcpt(context, inputLine.Substring(inputLine.IndexOf(" ")));
break;
}
context.WriteLine(MESSAGE_UNKNOWN_COMMAND);
break;
case "data":
Data(context);
break;
default:
context.WriteLine(MESSAGE_UNKNOWN_COMMAND);
break;
}
}
catch (Exception exception)
{
log.Error(String.Format("Connection {0}: Exception occured while processing commands: {1}", context.ConnectionId, exception), exception);
context.WriteLine(MESSAGE_SYSTEM_ERROR);
}
}
}
/// <summary>
/// Sends the welcome greeting to the client.
/// </summary>
private void SendWelcomeMessage(SMTPContext context)
{
context.WriteLine(WelcomeMessage);
}