/// <summary>
/// Run the TcpForwarder as background application. This method will also be called when running as a service.
/// In this mode, it will read "configuration.xml" to create TcpConnectionForwarder objects and run them.
/// </summary>
private static async Task RunBackgroundAsync(IBackgroundLogger logger)
{
IDictionary <long, TcpConnectionForwarder> forwarders = new SortedDictionary <long, TcpConnectionForwarder>();
List <ForwarderConfiguration> configs = GetConfiguration(logger);
StringBuilder logSb = new StringBuilder(); // for logging all created forwarders
Random seedGenerator = new Random();
// Create a forwarder for each config.
long nextId = 0;
foreach (ForwarderConfiguration config in configs)
{
long id = nextId++;
TcpConnectionForwarder forwarder;
try {
forwarder = new TcpConnectionForwarder(seedGenerator.Next(), config.RemoteHost, config.RemotePort, config.LocalPort, config.RemoteSslHostname,
TcpConnectionForwarderUtils.sslProtocols, config.LocalSslCert, TcpConnectionForwarderUtils.sslProtocols, config.MaxConcurrentConnections);
} catch (Exception ex) {
if (ExceptionUtils.ShouldExceptionBeRethrown(ex))
{
throw;
}
logger.LogError("Error when creating forwarder with ID " + id.ToString(CultureInfo.InvariantCulture) + ":\r\n" + FormatExceptionForLog(ex));
continue;
}
forwarders.Add(id, forwarder);
// Log the creation of a forwarder
if (logSb.Length > 0)
{
logSb.Append("\r\n");
}
logSb.Append("[ID: ").Append(id.ToString(CultureInfo.InvariantCulture))
.Append("] maxConcurrentConnections = ").Append(config.MaxConcurrentConnections)
.Append(", remoteHost = ").Append(config.RemoteHost)
.Append(", remotePort = " + config.RemotePort.ToString(CultureInfo.InvariantCulture))
.Append(", localPort = " + config.LocalPort.ToString(CultureInfo.InvariantCulture));
if (config.LocalSslCert != null)
{
logSb.Append("; Server SSL certificate:\r\n").Append(config.LocalSslCert.ToString());
}
}
logger.LogInfo("Created " + forwarders.Count.ToString(CultureInfo.InvariantCulture) + " TCP Connection Forwarders:\r\n" + logSb.ToString());
// Run the forwarders.
List <Task> forwarderTasks = new List <Task>();
foreach (KeyValuePair <long, TcpConnectionForwarder> kvp in forwarders)
{
TcpConnectionForwarder forwarder = kvp.Value;
Task t = forwarder.RunAsync();
if (t.IsCompleted)
{
// The task has already completed without an async wait - this should mean there was some exception.
try {
await t; // Await the task to catch an exception (e.g. thrown by the TcpListener).
} catch (Exception ex) {
if (ExceptionUtils.ShouldExceptionBeRethrown(ex))
{
throw;
}
logger.LogError("Error when starting forwarder with ID " + kvp.Key.ToString(CultureInfo.InvariantCulture) + ":\r\n" + FormatExceptionForLog(ex));
}
}
else
{
// Wrap the task so that exceptions immediately lead to the process termination.
Task newt = new Func <Task>(async() => await ExceptionUtils.WrapTaskForHandlingUnhandledExceptions(async() => await t))();
forwarderTasks.Add(newt);
}
}
// Await the forwarder tasks.
foreach (Task t in forwarderTasks)
{
await t;
}
}
private static List <ForwarderConfiguration> GetConfiguration(IBackgroundLogger errorLogger)
{
List <ForwarderConfiguration> configs = new List <ForwarderConfiguration>();
try {
// Read the XML configuration file.
XDocument doc;
using (FileStream fs = new FileStream(Path.Combine(Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location), "configuration.xml"), FileMode.Open, FileAccess.Read)) {
doc = XDocument.Load(fs);
}
XElement root = doc.Root;
if (root.Name.LocalName == "TcpForwarderConfiguration")
{
foreach (XNode node in root.Nodes())
{
try {
if (node is XElement && ((XElement)node).Name.LocalName == "Forwarder")
{
// Found an entry.
XElement el = (XElement)node;
XAttribute remoteHost = el.Attribute("remoteHost");
XAttribute remotePort = el.Attribute("remotePort");
XAttribute localPort = el.Attribute("localPort");
if (remoteHost == null || remotePort == null || localPort == null)
{
throw new ArgumentException("One of the required attributes (maxConcurrentConnections, remoteHost, remotePort, localPort) is missing.");
}
int maxConcurrentConnections;
XAttribute maxConcurrentConnectionsAttr = el.Attribute("maxConcurrentConnections");
if (maxConcurrentConnectionsAttr != null)
{
maxConcurrentConnections = int.Parse(maxConcurrentConnectionsAttr.Value, CultureInfo.InvariantCulture);
}
else
{
maxConcurrentConnections = 10000;
}
string remoteSslHostname = null;
XAttribute at = el.Attribute("remoteSslHostname");
if (at != null)
{
remoteSslHostname = at.Value;
}
X509Certificate2 cert = null;
at = el.Attribute("localSslCertFingerprint");
if (at != null)
{
cert = TcpConnectionForwarderUtils.GetCurrentUserOrLocalMachineCertificateFromFingerprint(at.Value);
if (cert == null)
{
throw new Exception("The certificate with fingerprint \"" + at.Value + "\" was not found.");
}
// check if we have enough privileges to get the private key of the certificate (when using the local machine's store,
// the program might need administrative rights to access the private key)
try {
System.Security.Cryptography.AsymmetricAlgorithm am = cert.PrivateKey;
GC.KeepAlive(am); // Ensure the compiler does not optimize-away the above call
} catch (Exception ex) {
if (ExceptionUtils.ShouldExceptionBeRethrown(ex))
{
throw;
}
throw new Exception("Error when retrieving the private key of the certificate. Make sure "
+ "you run this program with correct privileges.\r\n\r\n"
+ ex.GetType().ToString() + ": " + ex.Message, ex);
}
}
ForwarderConfiguration conf = new ForwarderConfiguration()
{
MaxConcurrentConnections = maxConcurrentConnections,
RemoteHost = remoteHost.Value,
RemotePort = ushort.Parse(remotePort.Value, CultureInfo.InvariantCulture),
LocalPort = ushort.Parse(localPort.Value, CultureInfo.InvariantCulture),
RemoteSslHostname = remoteSslHostname,
LocalSslCert = cert
};
configs.Add(conf);
}
} catch (Exception ex) {
if (ExceptionUtils.ShouldExceptionBeRethrown(ex))
{
throw;
}
errorLogger.LogError("An error occured when parsing the following XML configuration entry:\r\n"
+ node.ToString() + "\r\n\r\nError Details:\r\n" + FormatExceptionForLog(ex));
}
}
}
} catch (Exception ex) {
if (ExceptionUtils.ShouldExceptionBeRethrown(ex))
{
throw;
}
errorLogger.LogError("An error when reading the XML configuration.\r\n\r\nError Details:\r\n" + FormatExceptionForLog(ex));
}
return(configs);
}
