private byte[] CmdData(SMTPClientData clientData, Stream stream)
{
Write(stream, StartMailInput);
byte[] data = new byte[MaxMailSize];
byte[] buffer = new byte[1024];
int lastIndex = 0;
while (true)
{
int startIndex = (lastIndex > 5) ? lastIndex - 5: 0;
var bytesRead = stream.Read(buffer, 0, buffer.Length);
Array.Copy(buffer, 0, data, lastIndex, bytesRead);
lastIndex = GetEndOfDataIndex(buffer, startIndex);
if (lastIndex >= 0)
{
break;
}
lastIndex += bytesRead;
if (lastIndex >= data.Length)
{
return(MaxMailSizeExceeded);
}
}
clientData.body = new byte[lastIndex];
Array.Copy(data, clientData.body, clientData.body.Length);
return(OkReply);
}
private byte[] CmdHello(string[] cmd, SMTPClientData clientData)
{
if (cmd.Length < 2 || clientData.hostname != null)
{
return(ParameterSyntaxError); //TODO
}
clientData.hostname = cmd[1].ToLower();
return(OkReply);
}
private byte[] CmdMail(string[] cmd, SMTPClientData clientData)
{
if (cmd.Length < 2)
{
return(ParameterSyntaxError);
}
var segments = cmd[1].Split(':');
if (segments[0] != "FROM")
{
return(ParameterSyntaxError);
}
var sender = segments[1];
if (sender[0] != '<' || sender[sender.Length - 1] != '>')
{
return(ParameterSyntaxError);
}
clientData.from = sender;
return(OkReply);
}
private byte[] CmdAddRecipient(string[] cmd, SMTPClientData clientData)
{
if (cmd.Length < 2)
{
return(ParameterSyntaxError);
}
var segments = cmd[1].Split(':');
if (segments[0] != "TO")
{
return(ParameterSyntaxError);
}
var recipient = segments[1];
if (recipient[0] != '<' || recipient[recipient.Length - 1] != '>')
{
return(ParameterSyntaxError);
}
clientData.Recipients.Add(recipient);
return(OkReply);
}
private void HandleClient(TcpClient client)
{
Console.WriteLine("[==] BeepBoop: connection on " + port);
//client.ReceiveTimeout = client.SendTimeout = timeout;
Stream stream = client.GetStream();
if (Certificate != null)
{
var sslStream = new SslStream(stream, false);
Console.WriteLine("Authenticating...");
sslStream.AuthenticateAsServer(Certificate, false, SslProtocols.Tls, true);
Console.WriteLine("Authenticated");
stream = sslStream;
}
Write(stream, ServiceReadyReply);
byte[] reply;
var clientData = new SMTPClientData();
while (client.Connected)
{
var cmd = Read(stream)?.Split(' ');
if (cmd == null)
{
continue;
}
switch (cmd[0].ToUpper())
{
case "DATA":
reply = CmdData(clientData, stream);
break;
case "EXPN":
reply = NotImplemented;
break;
case "HELO":
reply = CmdHello(cmd, clientData);
break;
case "HELP":
reply = NotImplemented;
break;
case "MAIL":
reply = CmdMail(cmd, clientData);
break;
case "NOOP":
reply = OkReply;
break;
case "QUIT":
goto quit;
case "RCPT":
reply = CmdAddRecipient(cmd, clientData);
break;
case "RSET":
clientData.Clear();
reply = OkReply;
break;
case "SAML":
reply = NotImplemented;
break;
case "SEND":
reply = NotImplemented;
break;
case "SOML":
reply = NotImplemented;
break;
case "TURN":
reply = NotImplemented;
break;
case "VRFY":
reply = NotImplemented;
break;
default:
reply = CommandSyntaxError;
break;
}
Write(stream, reply);
}
quit:
Write(stream, ByeReply);
client.Close();
OnMailReceived.Invoke(clientData);
}