/// <summary>
/// Creates undelivered warning for user and places it to relay folder.
/// </summary>
/// <param name="relayInfo">Relay info</param>
/// <param name="error">SMTP returned error text.</param>
/// <param name="file">Messsage file.</param>
private void MakeUndeliveredWarning(RelayInfo relayInfo,string error,Stream file)
{
try
{
// If sender isn't specified, we can't send warning to sender.
// Just skip warning sending.
if(relayInfo.From.Length == 0){
return;
}
file.Position = relayInfo.MessageStartPos;
// Make new message
MimeConstructor mime = new MimeConstructor();
mime.From = "postmaster";
mime.To = new string[]{relayInfo.From};
mime.Subject = "Undelivered mail warning";
mime.Attachments.Add(new Attachment("data.eml",file));
string bodyTxt = Relay.UndelWarningTemplate;
bodyTxt = bodyTxt.Replace("<#RECEPTIENT>",relayInfo.To);
bodyTxt = bodyTxt.Replace("<#ERROR>",error);
bodyTxt = bodyTxt.Replace("<#UNDELIVERED_HOURS>",relayInfo.DeviveringForHours.ToString());
mime.Body = bodyTxt;
byte[] data = System.Text.Encoding.Default.GetBytes(mime.ConstructMime());
using(MemoryStream strm = new MemoryStream(data)){
m_pServer.ProcessAndStoreMessage("",new string[]{relayInfo.From},strm);
}
// byte[] data = System.Text.Encoding.Default.GetBytes(mime.ConstructMime());
// MailStore.StoreMessage("",new MemoryStream(data),relayInfo.From,"",true);
}
catch(Exception x)
{
Error.DumpError(x,new System.Diagnostics.StackTrace());
}
}
/// <summary>
/// Filters message.
/// </summary>
/// <param name="messageStream">Message stream which to filter.</param>
/// <param name="filteredStream">Filtered stream.</param>
/// <param name="sender">Senders email address.</param>
/// <param name="recipients">Recipients email addresses.</param>
/// <param name="api">Access to server API.</param>
public FilterResult Filter(MemoryStream messageStream,out MemoryStream filteredStream,string sender,string[] recipients,ServerAPI api)
{
messageStream.Position = 0;
filteredStream = messageStream; // we don't change message content, just return same stream
//--- Load data -----------------------
DataSet ds = new DataSet();
DataTable dt = ds.Tables.Add("KewWords");
dt.Columns.Add("Cost",typeof(int));
dt.Columns.Add("KeyWord");
dt = ds.Tables.Add("ContentMd5");
dt.Columns.Add("Description");
dt.Columns.Add("EntryMd5Value");
ds.ReadXml(Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location) + "\\lsSpam_db.xml");
//--- Do mime parts data md5 hash compare ----------------
ArrayList entries = new ArrayList();
MimeParser parser = new MimeParser(messageStream.ToArray());
GetEntries(parser.MimeEntries,entries);
System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create();
foreach(MimeEntry ent in entries){
if(ent.Data != null){
string md5Hash = Convert.ToBase64String(md5.ComputeHash(ent.Data));
foreach(DataRow dr in ds.Tables["ContentMd5"].Rows){
// Message contains blocked content(attachment,...)
if(dr["EntryMd5Value"].ToString() == md5Hash){
WriteFilterLog(DateTime.Now.ToString() + " From:" + sender + " Subject:\"" + parser.Subject + "\" Contained blocked content\r\n");
return FilterResult.DontStore;
}
}
}
}
byte[] topLines = new byte[2000];
if(messageStream.Length < 2000){
topLines = new byte[messageStream.Length];
}
messageStream.Read(topLines,0,topLines.Length);
string lines = System.Text.Encoding.ASCII.GetString(topLines).ToLower();
//--- Try spam keywords -----------
int totalCost = 0;
string keyWords = "";
DataView dv = ds.Tables["KewWords"].DefaultView;
dv.Sort = "Cost DESC";
foreach(DataRowView drV in dv){
if(lines.IndexOf(drV.Row["KeyWord"].ToString().ToLower()) > -1){
totalCost += Convert.ToInt32(drV.Row["Cost"]);
keyWords += drV.Row["KeyWord"].ToString() + " cost:" + drV.Row["Cost"].ToString() + " ";
// Check that total cost isn't exceeded
if(totalCost > 99){
//--- Send blocked note to sender
MimeConstructor m = new MimeConstructor();
m.Body = "Message was blocked by server and considered as SPAM !!!\n\nCaused by keywords: " + keyWords + "\n\nMaximum total cost is 100 !";
m.From = "postmaster";
m.To = new string[]{sender};
m.Attachments.Add(new Attachment("data.eml",messageStream.ToArray()));
using(MemoryStream msg = new MemoryStream(System.Text.Encoding.ASCII.GetBytes(m.ConstructMime()))){
api.StoreMessage("","",msg,sender,"",true,DateTime.Now,0);
}
WriteFilterLog(DateTime.Now.ToString() + " From:" + sender + " Blocked KeyWords: " + keyWords + "\r\n");
return FilterResult.DontStore;
}
}
}
//---------------------------------
return FilterResult.Store;
}
