protected static void HandleHeader(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.RawInput == "")
{
context._CurrentHandlers = _BodyHandlers;
}
else
{
context.Message.Headers.Add(input.RawInput);
}
}
protected static void OnMailFrom(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.Params.Length != 2 || input.Params.First().ToUpper() != "FROM:")
{
UnknownCommand(context, input);
}
else
{
context.Message.MailFrom = input.Params.Last();
}
context.WriteLine(250, "Ok");
}
protected static void HandleBody(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.RawInput == ".")
{
context.FireReceieMessage();
context._CurrentHandlers = _InitialHandlers;
context.Reset();
context.WriteLine(250, "Ok");
}
else
{
context.Message.Data.Add(input.RawInput);
}
}
protected static void OnEHLO(SmtpServerSession context, SmtpClientInputLine input)
{
if (context.Server.Credentials.Any())
{
context.WriteLine(
"250-localhost\r\n" +
"250-AUTH CRAM-MD5\r\n" +
"250-AUTH LOGIN CRAM-MD5\r\n" +
"250-AUTH=CRAM-MD5\r\n" +
"250 AUTH=LOGIN CRAM-MD5");
}
else
{
context.WriteLine(250, "Ok");
}
}
protected static void OnRcptTo(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.Params.Length != 2 || input.Params.First().ToUpper() != "TO:")
{
UnknownCommand(context, input);
return;
}
var rcptto = input.Params.Last();
if (context.Server.Credentials.Any() && context.User.IsAuthenticated == false)
{
context.WriteLine(554, "{0}: Recipient address rejected: Access denied", rcptto);
return;
}
context.Message.RcptTo.Add(rcptto);
context.WriteLine(250, "Ok");
}
protected static void AuthCRAMMD5(SmtpServerSession context, SmtpClientInputLine input)
{
try
{
const string AuthCRAMMD5Key = "AuthCRAMMD5Key";
context._CurrentHandlers = _AuthCRAMMD5Handlers;
if (input.Command.ToUpper() == "AUTH")
{
context.ClearIdentity();
context.Items[AuthCRAMMD5Key] = Guid.NewGuid().ToByteArray().ToBase64();
context.WriteLine(334, context.Items[AuthCRAMMD5Key] as string);
}
else
{
var pair = input.RawInput.Base64ToBytes().ToString(Encoding.UTF8).Split(' ');
context._User.Name = pair.First();
var credential = context.Server
.Credentials
.FirstOrDefault(c => c.UserName == context._User.Name);
if (credential == null)
{
FailAuthentication(context);
return;
}
var hmacmd5str = new HMACMD5(credential.Password.GetBytes())
.ComputeHash(context.Items[AuthCRAMMD5Key].ToString().Base64ToBytes())
.ToHexString();
context.Items.Remove(AuthCRAMMD5Key);
if (hmacmd5str != pair.Last())
{
FailAuthentication(context);
}
else
{
Authentication(context);
}
}
}
catch (FormatException)
{
context._CurrentHandlers = _InitialHandlers;
UnknownCommand(context, input);
}
}
protected static void AuthPlain(SmtpServerSession context, SmtpClientInputLine input)
{
try
{
context._CurrentHandlers = _AuthPlainHandlers;
if (input.Command.ToUpper() == "AUTH")
{
context.ClearIdentity();
var user = input.Params.Skip(1).FirstOrDefault() ?? "";
if (user.IsNullOrEmpty())
{
context.WriteLine(334, "Username:"******"Password:"******"Password:".GetBytes().ToBase64());
}
else
{
var password = input.RawInput.Base64ToBytes().ToString(Encoding.UTF8);
var found = context.Server.Credentials.Any(c => c.UserName == context.User.Name && c.Password == password);
if (found == false)
{
FailAuthentication(context);
}
else
{
Authentication(context);
}
}
}
catch (FormatException)
{
context._CurrentHandlers = _InitialHandlers;
UnknownCommand(context, input);
}
}
protected static void OnAuth(SmtpServerSession context, SmtpClientInputLine input)
{
var loginMethod = input.Params.First();
switch (loginMethod.ToUpper())
{
case "LOGIN":
AuthPlain(context, input);
return;
case "CRAM-MD5":
AuthCRAMMD5(context, input);
return;
default:
FailAuthentication(context);
break;
}
}
protected static void FailAuthentication(SmtpServerSession context)
{
context.ClearIdentity();
context._CurrentHandlers = _InitialHandlers;
context.WriteLine(535, " Error: authentication failed");
}
protected static void AuthPlain(SmtpServerSession context, SmtpClientInputLine input)
{
try
{
context._CurrentHandlers = _AuthPlainHandlers;
if (input.Command.ToUpper() == "AUTH")
{
context.ClearIdentity();
var user = input.Params.Skip(1).FirstOrDefault() ?? "";
if (user.IsNullOrEmpty())
{
context.WriteLine(334, "Username:"******"Password:"******"Password:".GetBytes().ToBase64());
}
else
{
var password = input.RawInput.Base64ToBytes().ToString(Encoding.UTF8);
var found = context.Server.Credentials.Any(c => c.UserName == context.User.Name && c.Password == password);
if (found == false)
{
FailAuthentication(context);
}
else
{
Authentication(context);
}
}
}
catch (FormatException)
{
context._CurrentHandlers = _InitialHandlers;
UnknownCommand(context, input);
}
}
protected static void Authentication(SmtpServerSession context)
{
context._User.IsAuthenticated = true;
context._CurrentHandlers = _InitialHandlers;
context.WriteLine(235, "Authentication successful");
}
protected static void OnMailFrom(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.Params.Length != 2 || input.Params.First().ToUpper() != "FROM:") UnknownCommand(context, input);
else
{
context.Message.MailFrom = input.Params.Last();
}
context.WriteLine(250, "Ok");
}
protected static void OnData(SmtpServerSession context, SmtpClientInputLine input)
{
context._CurrentHandlers = _HeaderHandlers;
context.WriteLine(354, "Ok");
}
protected static void HandleOK(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(250, "Ok");
}
protected static void UnknownCommand(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(502, "Error: command not implemented");
}
protected static void OnQuit(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(221, "Bye");
context.EndSession();
}
protected static void FailAuthentication(SmtpServerSession context)
{
context.ClearIdentity();
context._CurrentHandlers = _InitialHandlers;
context.WriteLine(535, " Error: authentication failed");
}
protected static void Authentication(SmtpServerSession context)
{
context._User.IsAuthenticated = true;
context._CurrentHandlers = _InitialHandlers;
context.WriteLine(235, "Authentication successful");
}
protected static void HandleBody(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.RawInput == ".")
{
context.FireReceieMessage();
context._CurrentHandlers = _InitialHandlers;
context.Reset();
context.WriteLine(250, "Ok");
}
else context.Message.Data.Add(input.RawInput);
}
protected static void HandleHeader(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.RawInput == "") context._CurrentHandlers = _BodyHandlers;
else context.Message.Headers.Add(input.RawInput);
}
protected static void OnData(SmtpServerSession context, SmtpClientInputLine input)
{
context._CurrentHandlers = _HeaderHandlers;
context.WriteLine(354, "Ok");
}
protected static void OnAuth(SmtpServerSession context, SmtpClientInputLine input)
{
var loginMethod = input.Params.First();
switch (loginMethod.ToUpper())
{
case "LOGIN":
AuthPlain(context, input);
return;
case "CRAM-MD5":
AuthCRAMMD5(context, input);
return;
default:
FailAuthentication(context);
break;
}
}
protected static void OnRcptTo(SmtpServerSession context, SmtpClientInputLine input)
{
if (input.Params.Length != 2 || input.Params.First().ToUpper() != "TO:")
{
UnknownCommand(context, input);
return;
}
var rcptto = input.Params.Last();
if (context.Server.Credentials.Any() && context.User.IsAuthenticated == false)
{
context.WriteLine(554, "{0}: Recipient address rejected: Access denied", rcptto);
return;
}
context.Message.RcptTo.Add(rcptto);
context.WriteLine(250, "Ok");
}
protected static void OnEHLO(SmtpServerSession context, SmtpClientInputLine input)
{
if (context.Server.Credentials.Any())
{
context.WriteLine(
"250-localhost\r\n" +
"250-AUTH CRAM-MD5\r\n" +
"250-AUTH LOGIN CRAM-MD5\r\n" +
"250-AUTH=CRAM-MD5\r\n" +
"250 AUTH=LOGIN CRAM-MD5");
}
else context.WriteLine(250, "Ok");
}
public SmtpServerSessionThread(SmtpServerSession session, Thread thread)
{
this.Session = session;
this.Thread = thread;
}
protected static void OnQuit(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(221, "Bye");
context.EndSession();
}
protected static void HandleOK(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(250, "Ok");
}
protected static void UnknownCommand(SmtpServerSession context, SmtpClientInputLine input)
{
context.WriteLine(502, "Error: command not implemented");
}
protected static void AuthCRAMMD5(SmtpServerSession context, SmtpClientInputLine input)
{
try
{
const string AuthCRAMMD5Key = "AuthCRAMMD5Key";
context._CurrentHandlers = _AuthCRAMMD5Handlers;
if (input.Command.ToUpper() == "AUTH")
{
context.ClearIdentity();
context.Items[AuthCRAMMD5Key] = Guid.NewGuid().ToByteArray().ToBase64();
context.WriteLine(334, context.Items[AuthCRAMMD5Key] as string);
}
else
{
var pair = input.RawInput.Base64ToBytes().ToString(Encoding.UTF8).Split(' ');
context._User.Name = pair.First();
var credential = context.Server
.Credentials
.FirstOrDefault(c => c.UserName == context._User.Name);
if (credential == null)
{
FailAuthentication(context);
return;
}
var hmacmd5str = new HMACMD5(credential.Password.GetBytes())
.ComputeHash(context.Items[AuthCRAMMD5Key].ToString().Base64ToBytes())
.ToHexString();
context.Items.Remove(AuthCRAMMD5Key);
if (hmacmd5str != pair.Last())
{
FailAuthentication(context);
}
else
{
Authentication(context);
}
}
}
catch (FormatException)
{
context._CurrentHandlers = _InitialHandlers;
UnknownCommand(context, input);
}
}
private void OnAcceptTcpClient(IAsyncResult ar)
{
var listener = ar.AsyncState as TcpListener;
try
{
var tcpClient = listener.EndAcceptTcpClient(ar);
lock (this)
{
CleanUpSessionTreadsList();
var session = new SmtpServerSession(this, tcpClient);
var sessionThread = new SmtpServerSessionThread(session,
new Thread(() =>
{
session.ExecuteSession();
}));
_SessionThreads.Add(sessionThread);
sessionThread.Thread.Start();
}
}
catch (ObjectDisposedException)
{
return;
}
listener.BeginAcceptTcpClient(OnAcceptTcpClient, listener);
}
public SmtpServerSessionThread(SmtpServerSession session, Thread thread)
{
this.Session = session;
this.Thread = thread;
}