/// <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);
}
}
