/// <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>
/// 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);
}
}
}
