/// <summary>
/// This method is called when asynchronous Connect method completes.
/// </summary>
/// <param name="ar">An IAsyncResult that stores state information and any user defined data for this asynchronous operation.</param>
private void ConnectCallback(IAsyncResult ar)
{
try
{
m_pSmtpClient.EndConnect(ar);
// Start TLS requested, start switching to SSL.
if (m_pActiveTarget.SslMode == SslMode.TLS)
{
m_pSmtpClient.BeginStartTLS(StartTlsCallback, null);
}
// Authentication requested, start authenticating.
else if (!string.IsNullOrEmpty(m_pActiveTarget.UserName))
{
m_pSmtpClient.BeginAuthenticate(m_pActiveTarget.UserName,
m_pActiveTarget.Password,
AuthenticateCallback,
null);
}
else
{
long messageSize = -1;
try
{
messageSize = m_pRelayItem.MessageStream.Length - m_pRelayItem.MessageStream.Position;
}
catch
{
// Stream doesn't support seeking.
}
m_pSmtpClient.BeginMailFrom(From, messageSize, MailFromCallback, null);
}
}
catch (Exception x)
{
try
{
// Release IP usage.
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
// Connect failed, if there are more target IPs, try next one.
if (!IsDisposed && !IsConnected && m_pTargets.Count > 0)
{
BeginConnect();
}
else
{
Dispose(x);
}
}
catch (Exception xx)
{
Dispose(xx);
}
}
}
/// <summary>
/// Starts connecting to best target.
/// </summary>
private void BeginConnect()
{
// No tagets, abort relay.
if (m_pTargets.Count == 0)
{
LogText("No relay target(s) for '" + m_pRelayItem.To + "', aborting.");
Dispose(new Exception("No relay target(s) for '" + m_pRelayItem.To + "', aborting."));
return;
}
// If maximum connections to specified target exceeded and there are more targets, try to get limit free target.
if (m_pServer.MaxConnectionsPerIP > 0)
{
// For DNS or load-balnced smart host relay, search free target if any.
if (m_pServer.RelayMode == Relay_Mode.Dns || m_pServer.SmartHostsBalanceMode == BalanceMode.LoadBalance)
{
foreach (Relay_Target t in m_pTargets)
{
// We found free target, stop searching.
if (m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address))
{
m_pActiveTarget = t;
m_pTargets.Remove(t);
break;
}
}
}
// Smart host fail-over mode, just check if it's free.
else
{
// Smart host IP limit not reached.
if (m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address))
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
}
}
// Just get first target.
else
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// If all targets has exeeded maximum allowed connection per IP address, end relay session,
// next relay cycle will try to relay again.
if (m_pActiveTarget == null)
{
LogText("All targets has exeeded maximum allowed connection per IP address, skip relay.");
Dispose(new Exception("All targets has exeeded maximum allowed connection per IP address, skip relay."));
return;
}
m_pSmtpClient.BeginConnect(new IPEndPoint(m_pLocalBindInfo.IP, 0), m_pActiveTarget.Target, false, new AsyncCallback(this.ConnectCallback), null);
}
/// <summary>
/// Is called when EHLO/HELO command has completed.
/// </summary>
/// <param name="op">Asynchronous operation.</param>
/// <exception cref="ArgumentNullException">Is raised when <b>op</b> is null reference.</exception>
private void ConnectCompleted(TCP_Client.ConnectAsyncOP op)
{
if (op == null)
{
throw new ArgumentNullException("op");
}
try
{
// Connect failed.
if (op.Error != null)
{
try
{
// Release IP usage.
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
// Connect failed, if there are more target IPs, try next one.
if (!this.IsDisposed && !this.IsConnected && m_pTargets.Count > 0)
{
BeginConnect();
}
else
{
Dispose(op.Error);
}
}
catch (Exception x1)
{
Dispose(x1);
}
}
// Connect suceeded.
else
{
// Do EHLO/HELO.
string hostName = string.IsNullOrEmpty(m_pLocalBindInfo.HostName) ? Dns.GetHostName() : m_pLocalBindInfo.HostName;
SMTP_Client.EhloHeloAsyncOP ehloOP = new SMTP_Client.EhloHeloAsyncOP(hostName);
ehloOP.CompletedAsync += delegate(object s, EventArgs <SMTP_Client.EhloHeloAsyncOP> e)
{
EhloCommandCompleted(ehloOP);
};
if (!m_pSmtpClient.EhloHeloAsync(ehloOP))
{
EhloCommandCompleted(ehloOP);
}
}
}
catch (Exception x)
{
Dispose(x);
}
}
/// <summary>
/// Completes relay session and does clean up. This method is thread-safe.
/// </summary>
/// <param name="exception">Exception happened or null if relay completed successfully.</param>
public void Dispose(Exception exception)
{
try
{
lock (this)
{
if (m_IsDisposed)
{
return;
}
try
{
m_pServer.OnSessionCompleted(this, exception);
}
catch
{
}
m_pServer.Sessions.Remove(this);
m_IsDisposed = true;
m_pLocalBindInfo = null;
m_pRelayItem = null;
m_pSmartHosts = null;
if (m_pSmtpClient != null)
{
m_pSmtpClient.Dispose();
m_pSmtpClient = null;
}
m_pTargets = null;
if (m_pActiveTarget != null)
{
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
}
m_pServer = null;
}
}
catch (Exception x)
{
if (m_pServer != null)
{
m_pServer.OnError(x);
}
}
}
/// <summary>
/// This method is called when asynchronous Connect method completes.
/// </summary>
/// <param name="ar">An IAsyncResult that stores state information and any user defined data for this asynchronous operation.</param>
private void ConnectCallback(IAsyncResult ar)
{
try
{
m_pSmtpClient.EndConnect(ar);
// Start TLS requested, start switching to SSL.
if (m_pActiveTarget.SslMode == SslMode.TLS)
{
m_pSmtpClient.BeginStartTLS(StartTlsCallback, null);
}
// Authentication requested, start authenticating.
else if (!string.IsNullOrEmpty(m_pActiveTarget.UserName))
{
m_pSmtpClient.BeginAuthenticate(m_pActiveTarget.UserName,
m_pActiveTarget.Password,
AuthenticateCallback,
null);
}
else
{
long messageSize = -1;
try
{
messageSize = m_pRelayItem.MessageStream.Length - m_pRelayItem.MessageStream.Position;
}
catch
{
// Stream doesn't support seeking.
}
m_pSmtpClient.BeginMailFrom(From, messageSize, MailFromCallback, null);
}
}
catch (Exception x)
{
try
{
// Release IP usage.
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
// Connect failed, if there are more target IPs, try next one.
if (!IsDisposed && !IsConnected && m_pTargets.Count > 0)
{
BeginConnect();
}
else
{
Dispose(x);
}
}
catch (Exception xx)
{
Dispose(xx);
}
}
}
/// <summary>
/// Starts connecting to best target.
/// </summary>
private void BeginConnect()
{
// No tagets, abort relay.
if (m_pTargets.Count == 0)
{
LogText("No relay target(s) for '" + m_pRelayItem.To + "', aborting.");
Dispose(new Exception("No relay target(s) for '" + m_pRelayItem.To + "', aborting."));
return;
}
// If maximum connections to specified target exceeded and there are more targets, try to get limit free target.
if (m_pServer.MaxConnectionsPerIP > 0)
{
// For DNS or load-balnced smart host relay, search free target if any.
if (m_pServer.RelayMode == Relay_Mode.Dns ||
m_pServer.SmartHostsBalanceMode == BalanceMode.LoadBalance)
{
foreach (Relay_Target t in m_pTargets)
{
// We found free target, stop searching.
if (m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address))
{
m_pActiveTarget = t;
m_pTargets.Remove(t);
break;
}
}
}
// Smart host fail-over mode, just check if it's free.
else
{
// Smart host IP limit not reached.
if (m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address))
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
}
}
// Just get first target.
else
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// If all targets has exeeded maximum allowed connection per IP address, end relay session,
// next relay cycle will try to relay again.
if (m_pActiveTarget == null)
{
LogText("All targets has exeeded maximum allowed connection per IP address, skip relay.");
Dispose(
new Exception(
"All targets has exeeded maximum allowed connection per IP address, skip relay."));
return;
}
m_pSmtpClient.BeginConnect(new IPEndPoint(m_pLocalBindInfo.IP, 0),
m_pActiveTarget.Target,
false,
ConnectCallback,
null);
}
/// <summary>
/// Completes relay session and does clean up. This method is thread-safe.
/// </summary>
/// <param name="exception">Exception happened or null if relay completed successfully.</param>
public void Dispose(Exception exception)
{
try
{
lock (this)
{
if (m_IsDisposed)
{
return;
}
try
{
m_pServer.OnSessionCompleted(this, exception);
}
catch {}
m_pServer.Sessions.Remove(this);
m_IsDisposed = true;
m_pLocalBindInfo = null;
m_pRelayItem = null;
m_pSmartHosts = null;
if (m_pSmtpClient != null)
{
m_pSmtpClient.Dispose();
m_pSmtpClient = null;
}
m_pTargets = null;
if (m_pActiveTarget != null)
{
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
}
m_pServer = null;
}
}
catch (Exception x)
{
if (m_pServer != null)
{
m_pServer.OnError(x);
}
}
}
/// <summary>
/// Starts connecting to best target.
/// </summary>
private void BeginConnect()
{
// No tagets, abort relay.
if (m_pTargets.Count == 0)
{
LogText("No relay target(s) for '" + m_pRelayItem.To + "', aborting.");
Dispose(new Exception("No relay target(s) for '" + m_pRelayItem.To + "', aborting."));
return;
}
// Maximum connections per IP limited.
if (m_pServer.MaxConnectionsPerIP > 0)
{
// For DNS or load-balnced smart host relay, search free target if any.
if (m_pServer.RelayMode == Relay_Mode.Dns || m_pServer.SmartHostsBalanceMode == BalanceMode.LoadBalance)
{
foreach (Relay_Target t in m_pTargets)
{
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(t.Target.Address);
// We have suitable local IP binding for the target.
if (m_pLocalBindInfo != null)
{
// We found free target, stop searching.
if (m_pServer.TryAddIpUsage(t.Target.Address))
{
m_pActiveTarget = t;
m_pTargets.Remove(t);
break;
}
// Connection per IP limit reached.
else
{
LogText("Skipping relay target (" + t.HostName + "->" + t.Target.Address + "), maximum connections to the specified IP has reached.");
}
}
// No suitable local IP binding, try next target.
else
{
LogText("Skipping relay target (" + t.HostName + "->" + t.Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
}
// Smart host fail-over mode, just check if it's free.
else
{
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(m_pTargets[0].Target.Address);
// We have suitable local IP binding for the target.
if (m_pLocalBindInfo != null)
{
// Smart host IP limit not reached.
if (m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address))
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// Connection per IP limit reached.
else
{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), maximum connections to the specified IP has reached.");
}
}
// No suitable local IP binding, try next target.
else
{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
}
// Just get first target.
else
{
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(m_pTargets[0].Target.Address);
// We have suitable local IP binding for the target.
if (m_pLocalBindInfo != null)
{
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// No suitable local IP binding, try next target.
else
{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
// We don't have suitable local IP end point for relay target.
// This may heppen for example: if remote server supports only IPv6 and we don't have local IPv6 local end point.
if (m_pLocalBindInfo == null)
{
LogText("No suitable IPv4/IPv6 local IP endpoint for relay target.");
Dispose(new Exception("No suitable IPv4/IPv6 local IP endpoint for relay target."));
return;
}
// If all targets has exeeded maximum allowed connection per IP address, end relay session,
// next relay cycle will try to relay again.
if (m_pActiveTarget == null)
{
LogText("All targets has exeeded maximum allowed connection per IP address, skip relay.");
Dispose(new Exception("All targets has exeeded maximum allowed connection per IP address, skip relay."));
return;
}
// Set SMTP host name.
m_pSmtpClient.LocalHostName = m_pLocalBindInfo.HostName;
// Start connecting to remote end point.
TCP_Client.ConnectAsyncOP connectOP = new TCP_Client.ConnectAsyncOP(new IPEndPoint(m_pLocalBindInfo.IP, 0), m_pActiveTarget.Target, false, null);
connectOP.CompletedAsync += delegate(object s, EventArgs <TCP_Client.ConnectAsyncOP> e){
ConnectCompleted(connectOP);
};
if (!m_pSmtpClient.ConnectAsync(connectOP))
{
ConnectCompleted(connectOP);
}
}
/// <summary>
/// Is called when EHLO/HELO command has completed.
/// </summary>
/// <param name="op">Asynchronous operation.</param>
/// <exception cref="ArgumentNullException">Is raised when <b>op</b> is null reference.</exception>
private void ConnectCompleted(TCP_Client.ConnectAsyncOP op)
{
if(op == null){
throw new ArgumentNullException("op");
}
try{
// Connect failed.
if(op.Error != null){
try{
// Release IP usage.
m_pServer.RemoveIpUsage(m_pActiveTarget.Target.Address);
m_pActiveTarget = null;
// Connect failed, if there are more target IPs, try next one.
if(!this.IsDisposed && !this.IsConnected && m_pTargets.Count > 0){
BeginConnect();
}
else{
Dispose(op.Error);
}
}
catch(Exception x1){
Dispose(x1);
}
}
// Connect suceeded.
else{
// Do EHLO/HELO.
string hostName = string.IsNullOrEmpty(m_pLocalBindInfo.HostName) ? Dns.GetHostName() : m_pLocalBindInfo.HostName;
SMTP_Client.EhloHeloAsyncOP ehloOP = new SMTP_Client.EhloHeloAsyncOP(hostName);
ehloOP.CompletedAsync += delegate(object s,EventArgs<SMTP_Client.EhloHeloAsyncOP> e){
EhloCommandCompleted(ehloOP);
};
if(!m_pSmtpClient.EhloHeloAsync(ehloOP)){
EhloCommandCompleted(ehloOP);
}
}
}
catch(Exception x){
Dispose(x);
}
}
/// <summary>
/// Starts connecting to best target.
/// </summary>
private void BeginConnect()
{
// No tagets, abort relay.
if(m_pTargets.Count == 0){
LogText("No relay target(s) for '" + m_pRelayItem.To + "', aborting.");
Dispose(new Exception("No relay target(s) for '" + m_pRelayItem.To + "', aborting."));
return;
}
// Maximum connections per IP limited.
if(m_pServer.MaxConnectionsPerIP > 0){
// For DNS or load-balnced smart host relay, search free target if any.
if(m_pServer.RelayMode == Relay_Mode.Dns || m_pServer.SmartHostsBalanceMode == BalanceMode.LoadBalance){
foreach(Relay_Target t in m_pTargets){
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(t.Target.Address);
// We have suitable local IP binding for the target.
if(m_pLocalBindInfo != null){
// We found free target, stop searching.
if(m_pServer.TryAddIpUsage(t.Target.Address)){
m_pActiveTarget = t;
m_pTargets.Remove(t);
break;
}
// Connection per IP limit reached.
else{
LogText("Skipping relay target (" + t.HostName + "->" + t.Target.Address + "), maximum connections to the specified IP has reached.");
}
}
// No suitable local IP binding, try next target.
else{
LogText("Skipping relay target (" + t.HostName + "->" + t.Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
}
// Smart host fail-over mode, just check if it's free.
else{
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(m_pTargets[0].Target.Address);
// We have suitable local IP binding for the target.
if(m_pLocalBindInfo != null){
// Smart host IP limit not reached.
if(m_pServer.TryAddIpUsage(m_pTargets[0].Target.Address)){
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// Connection per IP limit reached.
else{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), maximum connections to the specified IP has reached.");
}
}
// No suitable local IP binding, try next target.
else{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
}
// Just get first target.
else{
// Get local IP binding for remote IP.
m_pLocalBindInfo = m_pServer.GetLocalBinding(m_pTargets[0].Target.Address);
// We have suitable local IP binding for the target.
if(m_pLocalBindInfo != null){
m_pActiveTarget = m_pTargets[0];
m_pTargets.RemoveAt(0);
}
// No suitable local IP binding, try next target.
else{
LogText("Skipping relay target (" + m_pTargets[0].HostName + "->" + m_pTargets[0].Target.Address + "), no suitable local IPv4/IPv6 binding.");
}
}
// We don't have suitable local IP end point for relay target.
// This may heppen for example: if remote server supports only IPv6 and we don't have local IPv6 local end point.
if(m_pLocalBindInfo == null){
LogText("No suitable IPv4/IPv6 local IP endpoint for relay target.");
Dispose(new Exception("No suitable IPv4/IPv6 local IP endpoint for relay target."));
return;
}
// If all targets has exeeded maximum allowed connection per IP address, end relay session,
// next relay cycle will try to relay again.
if(m_pActiveTarget == null){
LogText("All targets has exeeded maximum allowed connection per IP address, skip relay.");
Dispose(new Exception("All targets has exeeded maximum allowed connection per IP address, skip relay."));
return;
}
// Set SMTP host name.
m_pSmtpClient.LocalHostName = m_pLocalBindInfo.HostName;
// Start connecting to remote end point.
TCP_Client.ConnectAsyncOP connectOP = new TCP_Client.ConnectAsyncOP(new IPEndPoint(m_pLocalBindInfo.IP,0),m_pActiveTarget.Target,false,null);
connectOP.CompletedAsync += delegate(object s,EventArgs<TCP_Client.ConnectAsyncOP> e){
ConnectCompleted(connectOP);
};
if(!m_pSmtpClient.ConnectAsync(connectOP)){
ConnectCompleted(connectOP);
}
}
