// if enabled, logs commands and replies
private void logCmdAndResp(string direction, string line)
{
if (AppGlobals.logVerbose)
{
AppGlobals.logMessage("{0}:{1} {2}: {3}", this._clientIP, this._sessionID, direction, line);
}
}
// dump the current settings
private static void dumpSettings()
{
// base/network
AppGlobals.writeConsole("Host name..................: {0}", AppGlobals.hostName);
AppGlobals.writeConsole("listen IP..................: {0}", AppGlobals.listenAddress);
AppGlobals.writeConsole("listen port................: {0}", AppGlobals.listenPort);
AppGlobals.writeConsole("Receive timeout............: {0}", AppGlobals.receiveTimeout);
// hardlimits
AppGlobals.writeConsole("Max errors.................: {0}", AppGlobals.maxSmtpErr);
AppGlobals.writeConsole("Max NOOP...................: {0}", AppGlobals.maxSmtpNoop);
AppGlobals.writeConsole("Max VRFY/EXPN..............: {0}", AppGlobals.maxSmtpVrfy);
AppGlobals.writeConsole("Max RCPT TO................: {0}", AppGlobals.maxSmtpRcpt);
// sessions
AppGlobals.writeConsole("Max messages per session...: {0}", AppGlobals.maxMessages);
AppGlobals.writeConsole("Max parallel sessions......: {0}", AppGlobals.maxSessions);
// messages
AppGlobals.writeConsole("Store message data.........: {0}", AppGlobals.storeData);
AppGlobals.writeConsole("Storage path...............: {0}", AppGlobals.storePath);
AppGlobals.writeConsole("Max message size...........: {0}", AppGlobals.maxDataSize);
// logs
AppGlobals.writeConsole("Logfiles path..............: {0}", AppGlobals.logPath);
AppGlobals.writeConsole("Verbose logging............: {0}", AppGlobals.logVerbose);
// tarpitting
AppGlobals.writeConsole("Initial banner delay.......: {0}", AppGlobals.bannerDelay);
AppGlobals.writeConsole("Error delay................: {0}", AppGlobals.errorDelay);
// filtering/rejecting
AppGlobals.writeConsole("Do tempfail (4xx) on DATA..: {0}", AppGlobals.doTempFail);
AppGlobals.writeConsole("Check for early talkers....: {0}", AppGlobals.earlyTalkers);
// DNS filtering
AppGlobals.writeConsole("DNS Whitelists.............: {0}", AppGlobals.whiteLists.Length);
AppGlobals.writeConsole("DNS Blacklists.............: {0}", AppGlobals.blackLists.Length);
// local domains/mailboxes
AppGlobals.writeConsole("Local domains..............: {0}", AppGlobals.LocalDomains.Count);
AppGlobals.writeConsole("Local mailboxes............: {0}", AppGlobals.LocalMailBoxes.Count);
}
// closes the socket, terminates the session
private void closeSession()
{
if (null != this._client)
{
if (this._client.Connected)
{
sleepDown(25);
}
try { this._client.Close(); this._client = null; }
catch { }
if (!string.IsNullOrEmpty(this._clientIP))
{
AppGlobals.writeConsole("client {0} disconnected, sess={1}, ID={2}.", this._clientIP, this._sessCount, this._sessionID);
}
}
this._initOk = false;
long sesscount = AppGlobals.removeSession();
resetSession();
}
private string _mailDom = null; // domain part of a mail address
#endregion
#region "instance"
// init
public SMTPsession(TcpClient client)
{
try
{
this._sessCount = AppGlobals.addSession();
this._sessionID = AppGlobals.sessionID();
this._hostName = AppGlobals.hostName;
if (null != AppGlobals.LocalDomains)
{
this._mailDomains = AppGlobals.LocalDomains;
}
if (null != AppGlobals.LocalMailBoxes)
{
this._mailBoxes = AppGlobals.LocalMailBoxes;
}
this._client = client;
this._clientIP = this._client.Client.RemoteEndPoint.ToString();
int i = this._clientIP.IndexOf(':');
if (-1 != i)
{
this._clientIP = this._clientIP.Substring(0, i);
}
this._client.ReceiveTimeout = AppGlobals.receiveTimeout;
this._stream = this._client.GetStream();
this._reader = new StreamReader(this._stream);
this._writer = new StreamWriter(this._stream);
this._writer.NewLine = "\r\n";
this._writer.AutoFlush = true;
AppGlobals.writeConsole("client {0} connected, sess={1}, ID={2}.", this._clientIP, this._sessCount, this._sessionID);
this._initOk = true;
}
catch (Exception ex)
{
AppGlobals.writeConsole("SMTPsession::Exception: " + ex.Message);
closeSession();
}
}
// logs session infos to logfile (at each mail); if you want to change
// the log record format, this is the place to do it, just change the
// "cols.Add" to include the columns you want and there you'll go :-)
private void logSession()
{
// check if already logged
if (this._lastMsgID == this._msgCount)
{
return;
}
this._lastMsgID = this._msgCount;
// check if we got some data
if (string.IsNullOrEmpty(this._heloStr))
{
this._heloStr = "-no-helo-";
}
if (string.IsNullOrEmpty(this._mailFrom))
{
this._mailFrom = "-no-from-";
}
// if (0 == this._rcptTo.Count) return;
// build the log array
List <string> cols = new List <string>();
// current date/time
cols.Add(DateTime.UtcNow.ToString("u"));
// start date, session ID, client IP, helo
cols.Add(this._startDate.ToString("u"));
cols.Add(this._sessionID.ToString());
cols.Add(this._clientIP);
cols.Add(this._heloStr);
// mail from
if (!string.IsNullOrEmpty(this._mailFrom))
{
cols.Add(this._mailFrom);
}
else
{
cols.Add("");
}
// rcpt to
if (this._rcptTo.Count > 0)
{
cols.Add(this._rcptTo.Count.ToString());
cols.Add(string.Join(",", this._rcptTo));
}
else
{
cols.Add("0");
cols.Add("-no-rcpt-");
}
// message # and message file name (if any)
cols.Add(this._msgCount.ToString());
if (!string.IsNullOrEmpty(this._msgFile))
{
cols.Add(this._msgFile);
}
else
{
cols.Add("-no-file-");
}
// dns listing
if (!string.IsNullOrEmpty(this._dnsListType))
{
cols.Add(this._dnsListType);
cols.Add(this._dnsListName);
cols.Add(this._dnsListValue);
}
else
{
cols.Add("-not-listed-");
cols.Add("-none-");
cols.Add("0.0.0.0");
}
// early talker
if (this._earlyTalker)
{
cols.Add("1");
}
else
{
cols.Add("0");
}
// noop/vrfy/err
cols.Add(this._noopCount.ToString());
cols.Add(this._vrfyCount.ToString());
cols.Add(this._errCount.ToString());
// builds and logs the record
//string logRec = string.Join("|", cols);
//AppGlobals.logSession("{0}", logRec);
// builds the log record format string
StringBuilder logFmt = new StringBuilder("{0}");
for (int i = 1; i < cols.Count; i++)
{
logFmt.Append("|{" + i + "}");
}
// log the record
AppGlobals.logSession(logFmt.ToString(), cols.ToArray <string>());
}
// main entry point
static int Main(string[] args)
{
// our internal stuff
IPAddress listenAddr = IPAddress.Loopback;
int listenPort = 25;
int retCode = 0;
// load the config
loadConfig();
// tell we're starting up and, if verbose, dump config parameters
AppGlobals.writeConsole("{0} {1} starting up (NET {2})", AppGlobals.appName, AppGlobals.appVersion, AppGlobals.appRuntime);
if (AppGlobals.logVerbose)
{
dumpSettings();
}
// setup the listening IP:port
listenAddr = AppGlobals.listenIP;
listenPort = AppGlobals.listenPort;
// try starting the listener
try
{
listener = new TcpListener(listenAddr, listenPort);
listener.Start();
}
catch (Exception ex)
{
AppGlobals.writeConsole("Listener::Error: " + ex.Message);
return(1);
}
// tell we're ready to accept connections
AppGlobals.writeConsole("Listening for connections on {0}:{1}", listenAddr, listenPort);
// run until interrupted (Ctrl-C in our case)
while (!timeToStop)
{
try
{
// wait for an incoming connection, accept it and spawn a thread to handle it
SMTPsession handler = new SMTPsession(listener.AcceptTcpClient());
Thread thread = new System.Threading.Thread(new ThreadStart(handler.handleSession));
thread.Start();
}
catch (Exception ex)
{
// we got an error
retCode = 2;
AppGlobals.writeConsole("Handler::Error: " + ex.Message);
timeToStop = true;
}
}
// finalize
if (null != listener)
{
try { listener.Stop(); }
catch { }
}
return(retCode);
}
// loads/parses the config values
static void loadConfig()
{
// listen address
IPAddress listenIP = IPAddress.Loopback;
string listenAddress = ConfigurationManager.AppSettings["ListenAddress"];
if (String.IsNullOrEmpty(listenAddress))
{
listenAddress = "127.0.0.1";
}
if (false == IPAddress.TryParse(listenAddress, out listenIP))
{
listenAddress = "127.0.0.1";
listenIP = IPAddress.Loopback;
}
// listen port
int listenPort = int.Parse(ConfigurationManager.AppSettings["ListenPort"]);
if ((listenPort < 1) || (listenPort > 65535))
{
listenPort = 25;
}
// receive timeout
int receiveTimeout = int.Parse(ConfigurationManager.AppSettings["ReceiveTimeOut"]);
if (receiveTimeout < 0)
{
receiveTimeout = 0;
}
// hostname (for the banner)
string hostName = ConfigurationManager.AppSettings["HostName"];
if (string.IsNullOrEmpty(hostName))
{
hostName = System.Net.Dns.GetHostEntry("").HostName;
}
// true=emits a "tempfail" when receiving the DATA command
bool doTempFail = bool.Parse(ConfigurationManager.AppSettings["DoTempFail"]);
// true=stores the email envelope and data into files
bool storeData = bool.Parse(ConfigurationManager.AppSettings["StoreData"]);
// max size for a given email message
long storeSize = long.Parse(ConfigurationManager.AppSettings["MaxDataSize"]);
if (storeSize < 0)
{
storeSize = 0;
}
// max # of messages for a session
int maxMsgs = int.Parse(ConfigurationManager.AppSettings["MaxMessages"]);
if (maxMsgs < 1)
{
maxMsgs = 10;
}
// path for the email storage
string storePath = ConfigurationManager.AppSettings["StorePath"];
if (String.IsNullOrEmpty(storePath))
{
storePath = Path.GetTempPath();
}
if (!storePath.EndsWith("\\"))
{
storePath = storePath + "\\";
}
// max # of parallel sessions, further requests will be rejected
long maxSessions = long.Parse(ConfigurationManager.AppSettings["MaxSessions"]);
if (maxSessions < 1)
{
maxSessions = 16;
}
// path for the log file
string logPath = ConfigurationManager.AppSettings["LogPath"];
if (String.IsNullOrEmpty(logPath))
{
logPath = Path.GetTempPath();
}
if (!logPath.EndsWith("\\"))
{
logPath = logPath + "\\";
}
// verbose logging
bool verboseLog = bool.Parse(ConfigurationManager.AppSettings["VerboseLogging"]);
// early talker detection
bool earlyTalk = bool.Parse(ConfigurationManager.AppSettings["DoEarlyTalk"]);
// DNS whitelist providers, empty to not perform the check
string whiteLists = ConfigurationManager.AppSettings["RWLproviders"];
string[] RWL = null;
if (!string.IsNullOrEmpty(whiteLists))
{
RWL = whiteLists.Split(',');
}
// DNS blacklist providers, empty to not perform the check
string blackLists = ConfigurationManager.AppSettings["RBLproviders"];
string[] RBL = null;
if (!string.IsNullOrEmpty(blackLists))
{
RBL = blackLists.Split(',');
}
// hardlimits for errors, noop etc..
int maxErrors = int.Parse(ConfigurationManager.AppSettings["MaxSmtpErrors"]);
if (maxErrors < 1)
{
maxErrors = 5;
}
int maxNoop = int.Parse(ConfigurationManager.AppSettings["MaxSmtpNoop"]);
if (maxNoop < 1)
{
maxNoop = 7;
}
int maxVrfy = int.Parse(ConfigurationManager.AppSettings["MaxSmtpVrfy"]);
if (maxVrfy < 1)
{
maxVrfy = 10;
}
int maxRcpt = int.Parse(ConfigurationManager.AppSettings["MaxSmtpRcpt"]);
if (maxRcpt < 1)
{
maxRcpt = 100;
}
// delays (tarpitting)
int bannerDelay = int.Parse(ConfigurationManager.AppSettings["BannerDelay"]);
if (bannerDelay < 0)
{
bannerDelay = 0;
}
int errorDelay = int.Parse(ConfigurationManager.AppSettings["ErrorDelay"]);
if (errorDelay < 0)
{
errorDelay = 0;
}
// local domains and mailboxes
List <string> domains = new List <string>();
List <string> mailboxes = new List <string>();
string fileName = ConfigurationManager.AppSettings["LocalDomains"];
if (!string.IsNullOrEmpty(fileName))
{
domains = AppGlobals.loadFile(fileName);
}
fileName = ConfigurationManager.AppSettings["LocalMailBoxes"];
if (!string.IsNullOrEmpty(fileName))
{
mailboxes = AppGlobals.loadFile(fileName);
}
// set the global values
AppGlobals.listenIP = listenIP;
AppGlobals.listenAddress = listenAddress;
AppGlobals.listenPort = listenPort;
AppGlobals.receiveTimeout = receiveTimeout;
AppGlobals.hostName = hostName.ToLower();
AppGlobals.doTempFail = doTempFail;
AppGlobals.storeData = storeData;
AppGlobals.maxDataSize = storeSize;
AppGlobals.maxMessages = maxMsgs;
AppGlobals.storePath = storePath;
AppGlobals.maxSessions = maxSessions;
AppGlobals.logPath = logPath;
AppGlobals.logVerbose = verboseLog;
AppGlobals.earlyTalkers = earlyTalk;
AppGlobals.whiteLists = RWL;
AppGlobals.blackLists = RBL;
AppGlobals.maxSmtpErr = maxErrors;
AppGlobals.maxSmtpNoop = maxNoop;
AppGlobals.maxSmtpVrfy = maxVrfy;
AppGlobals.maxSmtpRcpt = maxRcpt;
AppGlobals.bannerDelay = bannerDelay;
AppGlobals.errorDelay = errorDelay;
AppGlobals.LocalDomains = domains;
AppGlobals.LocalMailBoxes = mailboxes;
}