/// <summary>
/// Examines an email to try to identify detailed bounce information from it.
/// </summary>
/// <param name="filename">Path and filename of the file being processed.</param>
/// <param name="message">The entire text content for an email (headers and body).</param>
/// <returns>An EmailProcessingResult value indicating whether the the email was
/// successfully processed or not.</returns>
public EmailProcessingDetails ProcessBounceEmail(string message)
{
EmailProcessingDetails bounceDetails = new EmailProcessingDetails();
MimeMessage msg = MimeMessage.Parse(message);
if (msg == null)
{
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorContent;
bounceDetails.BounceIdentifier = BounceIdentifier.NotIdentifiedAsABounce;
return(bounceDetails);
}
// "X-Recipient" should contain what Manta originally set as the "return-path" when sending.
MessageHeader returnPath = msg.Headers.GetFirstOrDefault("X-Recipient");
if (returnPath == null)
{
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorNoReturnPath;
bounceDetails.BounceIdentifier = BounceIdentifier.UnknownReturnPath;
return(bounceDetails);
}
string rcptTo = string.Empty;
int internalSendID = 0;
if (!ReturnPathManager.TryDecode(returnPath.Value, out rcptTo, out internalSendID))
{
// Not a valid Return-Path so can't process.
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorNoReturnPath;
bounceDetails.BounceIdentifier = BounceIdentifier.UnknownReturnPath;
return(bounceDetails);
}
MantaBounceEvent bounceEvent = new MantaBounceEvent();
bounceEvent.EmailAddress = rcptTo;
bounceEvent.SendID = SendDB.GetSend(internalSendID).ID;
// TODO: Might be good to get the DateTime found in the email.
bounceEvent.EventTime = DateTime.UtcNow;
// These properties are both set according to the SMTP code we find, if any.
bounceEvent.BounceInfo.BounceCode = MantaBounceCode.Unknown;
bounceEvent.BounceInfo.BounceType = MantaBounceType.Unknown;
bounceEvent.EventType = MantaEventType.Bounce;
// First, try to find a NonDeliveryReport body part as that's the proper way for an MTA
// to tell us there was an issue sending the email.
BouncePair bouncePair;
string bounceMsg;
BodyPart deliveryReportBodyPart;
string deliveryReport = string.Empty;
if (FindFirstBodyPartByMediaType(msg.BodyParts, "message/delivery-status", out deliveryReportBodyPart))
{
// If we've got a delivery report, check it for info.
// Abuse report content may have long lines whitespace folded.
deliveryReport = MimeMessage.UnfoldHeaders(deliveryReportBodyPart.GetDecodedBody());
if (ParseNdr(deliveryReport, out bouncePair, out bounceMsg, out bounceDetails))
{
// Successfully parsed.
bounceEvent.BounceInfo = bouncePair;
bounceEvent.Message = bounceMsg;
// Write BounceEvent to DB.
Save(bounceEvent);
bounceDetails.ProcessingResult = EmailProcessingResult.SuccessBounce;
return(bounceDetails);
}
}
// We're still here so there was either no NDR part or nothing contained within it that we could
// interpret so have to check _all_ body parts for something useful.
if (FindBounceReason(msg.BodyParts, out bouncePair, out bounceMsg, out bounceDetails))
{
bounceEvent.BounceInfo = bouncePair;
bounceEvent.Message = bounceMsg;
// Write BounceEvent to DB.
Save(bounceEvent);
bounceDetails.ProcessingResult = EmailProcessingResult.SuccessBounce;
return(bounceDetails);
}
// Nope - no clues relating to why the bounce occurred.
bounceEvent.BounceInfo.BounceType = MantaBounceType.Unknown;
bounceEvent.BounceInfo.BounceCode = MantaBounceCode.Unknown;
bounceEvent.Message = string.Empty;
bounceDetails.BounceIdentifier = BounceIdentifier.NotIdentifiedAsABounce;
bounceDetails.ProcessingResult = EmailProcessingResult.Unknown;
return(bounceDetails);
}
/// <summary>
/// Looks through a feedback loop email looking for something to identify it as an abuse report and who it relates to.
/// If found, logs the event.
///
/// How to get the info depending on the ESP (and this is likely to be the best order to check for each too):
/// Abuse Report Original-Mail-From. [Yahoo]
/// Message-ID from body part child with content-type of message/rfc822. [AOL]
/// Return-Path in main message headers. [Hotmail]
/// </summary>
/// <param name="message">The feedback look email.</param>
public EmailProcessingDetails ProcessFeedbackLoop(string content)
{
EmailProcessingDetails processingDetails = new EmailProcessingDetails();
MimeMessage message = MimeMessage.Parse(content);
if (message == null)
{
processingDetails.ProcessingResult = EmailProcessingResult.ErrorContent;
return(processingDetails);
}
try
{
// Step 1: Yahoo! provide useable Abuse Reports (AOL's are all redacted).
//Look for abuse report
BodyPart abuseBodyPart = null;
if (this.FindFirstBodyPartByMediaType(message.BodyParts, "message/feedback-report", out abuseBodyPart))
{
// Found an abuse report body part to examine.
// Abuse report content may have long lines whitespace folded.
string abuseReportBody = MimeMessage.UnfoldHeaders(abuseBodyPart.GetDecodedBody());
using (StringReader reader = new StringReader(abuseReportBody))
{
while (reader.Peek() > -1)
{
string line = reader.ReadToCrLf();
// The original mail from value will be the return-path we'd set so we should be able to get all the values we need from that.
if (line.StartsWith("Original-Mail-From:", StringComparison.OrdinalIgnoreCase))
{
string tmp = line.Substring("Original-Mail-From: ".Length - 1);
try
{
int internalSendID = -1;
string rcptTo = string.Empty;
if (ReturnPathManager.TryDecode(tmp, out rcptTo, out internalSendID))
{
// NEED TO LOG TO DB HERE!!!!!
Send snd = SendDB.GetSend(internalSendID);
Save(new MantaAbuseEvent
{
EmailAddress = rcptTo,
EventTime = DateTime.UtcNow,
EventType = MantaEventType.Abuse,
SendID = (snd == null ? string.Empty : snd.ID)
});
processingDetails.ProcessingResult = EmailProcessingResult.SuccessAbuse;
return(processingDetails);
}
}
catch (Exception)
{
// Must be redacted
break;
}
}
}
}
}
// Function to use against BodyParts to find a return-path header.
Func <MessageHeaderCollection, bool> checkForReturnPathHeaders = delegate(MessageHeaderCollection headers)
{
MessageHeader returnPathHeader = headers.GetFirstOrDefault("Return-Path");
if (returnPathHeader != null && !string.IsNullOrWhiteSpace(returnPathHeader.Value))
{
int internalSendID = -1;
string rcptTo = string.Empty;
if (ReturnPathManager.TryDecode(returnPathHeader.Value, out rcptTo, out internalSendID))
{
if (!rcptTo.StartsWith("redacted@", StringComparison.OrdinalIgnoreCase))
{
// NEED TO LOG TO DB HERE!!!!!
Send snd = SendDB.GetSend(internalSendID);
Save(new MantaAbuseEvent
{
EmailAddress = rcptTo,
EventTime = DateTime.UtcNow,
EventType = MantaEventType.Abuse,
SendID = (snd == null ? string.Empty : snd.ID)
});
return(true);
}
}
}
MessageHeader messageIdHeader = headers.GetFirstOrDefault("Message-ID");
if (messageIdHeader != null && messageIdHeader.Value.Length > 33)
{
string tmp = messageIdHeader.Value.Substring(1, 32);
Guid messageID;
if (Guid.TryParse(tmp, out messageID))
{
int internalSendID = -1;
string rcptTo = string.Empty;
tmp = ReturnPathManager.GetReturnPathFromMessageID(messageID);
if (ReturnPathManager.TryDecode(tmp, out rcptTo, out internalSendID))
{
// NEED TO LOG TO DB HERE!!!!!
Send snd = SendDB.GetSend(internalSendID);
Save(new MantaAbuseEvent
{
EmailAddress = rcptTo,
EventTime = DateTime.UtcNow,
EventType = MantaEventType.Abuse,
SendID = (snd == null ? string.Empty : snd.ID)
});
return(true);
}
}
}
return(false);
}
;
// Step 2: AOL give redacted Abuse Reports but include the original email as a bodypart; find that.
BodyPart childMessageBodyPart;
if (FindFirstBodyPartByMediaType(message.BodyParts, "message/rfc822", out childMessageBodyPart))
{
if (childMessageBodyPart.ChildMimeMessage != null)
{
if (checkForReturnPathHeaders(childMessageBodyPart.ChildMimeMessage.Headers))
{
processingDetails.ProcessingResult = EmailProcessingResult.SuccessAbuse;
return(processingDetails);
}
}
}
// Step 3: Hotmail don't do Abuse Reports, they just return our email to us exactly as we sent it.
if (checkForReturnPathHeaders(message.Headers))
{
processingDetails.ProcessingResult = EmailProcessingResult.SuccessAbuse;
return(processingDetails);
}
}
catch (Exception) { }
Logging.Debug("Failed to find return path!");
processingDetails.ProcessingResult = EmailProcessingResult.ErrorNoReturnPath;
return(processingDetails);
}
/// <summary>
/// Queues the email for relaying.
/// </summary>
private async Task <SmtpServerTransactionAsyncResult> QueueForRelayingAsync()
{
// The email is for relaying.
Guid messageID = Guid.NewGuid();
// Look for any MTA control headers.
MessageHeaderCollection headers = MessageManager.GetMessageHeaders(Data);
// Will not be null if the SendGroupID header was present.
MessageHeader ipGroupHeader = headers.SingleOrDefault(m => m.Name.Equals(MessageHeaderNames.SendGroupID, StringComparison.OrdinalIgnoreCase));
// Parameter will hold the MtaIPGroup that will be used to relay this message.
VirtualMtaGroup mtaGroup = null;
int ipGroupID = 0;
if (ipGroupHeader != null)
{
if (int.TryParse(ipGroupHeader.Value, out ipGroupID))
{
mtaGroup = VirtualMtaManager.GetVirtualMtaGroup(ipGroupID);
}
}
#region Look for a send id, if one doesn't exist create it.
MessageHeader sendIdHeader = headers.SingleOrDefault(h => h.Name.Equals(MessageHeaderNames.SendID, StringComparison.OrdinalIgnoreCase));
int internalSendId = -1;
if (sendIdHeader != null)
{
Send sndID = await SendManager.Instance.GetSendAsync(sendIdHeader.Value);
if (sndID.SendStatus == SendStatus.Discard)
{
return(SmtpServerTransactionAsyncResult.FailedSendDiscarding);
}
internalSendId = sndID.InternalID;
}
else
{
Send sndID = await SendManager.Instance.GetDefaultInternalSendIdAsync();
if (sndID.SendStatus == SendStatus.Discard)
{
return(SmtpServerTransactionAsyncResult.FailedSendDiscarding);
}
internalSendId = sndID.InternalID;
}
#endregion
#region Generate Return Path
string returnPath = string.Empty;
// Can only return path to messages with one rcpt to
if (RcptTo.Count == 1)
{
// Need to check to see if the message contains a return path overide domain.
MessageHeader returnPathDomainOverrideHeader = headers.SingleOrDefault(h => h.Name.Equals(MessageHeaderNames.ReturnPathDomain, StringComparison.OrdinalIgnoreCase));
if (returnPathDomainOverrideHeader != null &&
MtaParameters.LocalDomains.Count(d => d.Hostname.Equals(returnPathDomainOverrideHeader.Value, StringComparison.OrdinalIgnoreCase)) > 0)
{
// The message contained a local domain in the returnpathdomain
// header so use it instead of the default.
returnPath = ReturnPathManager.GenerateReturnPath(RcptTo[0], internalSendId, returnPathDomainOverrideHeader.Value);
}
else
{
// The message didn't specify a return path overide or it didn't
// contain a localdomain so use the default.
returnPath = ReturnPathManager.GenerateReturnPath(RcptTo[0], internalSendId);
}
// Insert the return path header.
Data = MessageManager.AddHeader(Data, new MessageHeader("Return-Path", "<" + returnPath + ">"));
}
else
{
// multiple rcpt's so can't have unique return paths, use generic mail from.
returnPath = MailFrom;
}
#endregion
#region Generate a message ID header
string msgIDHeaderVal = "<" + messageID.ToString("N") + MailFrom.Substring(MailFrom.LastIndexOf("@")) + ">";
// If there is already a message header, remove it and add our own. required for feedback loop processing.
if (headers.Count(h => h.Name.Equals("Message-ID", StringComparison.OrdinalIgnoreCase)) > 0)
{
Data = MessageManager.RemoveHeader(Data, "Message-ID");
}
// Add the new message-id header.
Data = MessageManager.AddHeader(Data, new MessageHeader("Message-ID", msgIDHeaderVal));
#endregion
#region Get message priority
var msgPriority = RabbitMqPriority.Low;
var priorityHeader = headers.GetFirstOrDefault(MessageHeaderNames.Priority);
if (priorityHeader != null)
{
var outVal = 0;
if (int.TryParse(priorityHeader.Value, out outVal))
{
if (outVal >= 0)
{
msgPriority = outVal < 3 ? (RabbitMqPriority)(byte)outVal
: RabbitMqPriority.High;
}
}
}
#endregion
// Remove any control headers.
headers = new MessageHeaderCollection(headers.Where(h => h.Name.StartsWith(MessageHeaderNames.HeaderNamePrefix, StringComparison.OrdinalIgnoreCase)));
foreach (MessageHeader header in headers)
{
Data = MessageManager.RemoveHeader(Data, header.Name);
}
// If the MTA group doesn't exist or it's not got any IPs, use the default.
if (mtaGroup == null ||
mtaGroup.VirtualMtaCollection.Count == 0)
{
ipGroupID = VirtualMtaManager.GetDefaultVirtualMtaGroup().ID;
}
// Attempt to Enqueue the Email for Relaying.
var enqueued = await QueueManager.Instance.Enqueue(messageID, ipGroupID, internalSendId, returnPath, RcptTo.ToArray(), Data, msgPriority);
return(enqueued ? SmtpServerTransactionAsyncResult.SuccessMessageQueued
: SmtpServerTransactionAsyncResult.FailedToEnqueue);
}