public static NATKeepAliveMessage ParseNATKeepAliveMessage(byte[] buffer)
{
if (buffer != null && buffer.Length == 20)
{
byte[] sendToAddrBuffer = new byte[4];
Buffer.BlockCopy(buffer, 0, sendToAddrBuffer, 0, 4);
IPAddress sendToAddress = new IPAddress(sendToAddrBuffer);
int sendToPort = BitConverter.ToInt32(buffer, 4);
int proxyProtocol = BitConverter.ToInt32(buffer, 8);
byte[] proxyFromAddrBuffer = new byte[4];
Buffer.BlockCopy(buffer, 12, proxyFromAddrBuffer, 0, 4);
int sendFromPort = BitConverter.ToInt32(buffer, 16);
SIPEndPoint proxySendFrom = new SIPEndPoint((SIPProtocolsEnum)proxyProtocol, new IPEndPoint(new IPAddress(proxyFromAddrBuffer), sendFromPort));
//SIPProtocolsEnum protocol = SIPProtocolsType.GetProtocolTypeFromId(BitConverter.ToInt32(buffer, 16));
//SIPProtocolsEnum protocol = SIPProtocolsEnum.udp;
NATKeepAliveMessage natKeepAliveMsg = new NATKeepAliveMessage(proxySendFrom, new IPEndPoint(sendToAddress, sendToPort));
return natKeepAliveMsg;
}
else
{
return null;
}
}
public static NATKeepAliveMessage ParseNATKeepAliveMessage(byte[] buffer)
{
if (buffer != null && buffer.Length == 20)
{
byte[] sendToAddrBuffer = new byte[4];
Buffer.BlockCopy(buffer, 0, sendToAddrBuffer, 0, 4);
IPAddress sendToAddress = new IPAddress(sendToAddrBuffer);
int sendToPort = BitConverter.ToInt32(buffer, 4);
int proxyProtocol = BitConverter.ToInt32(buffer, 8);
byte[] proxyFromAddrBuffer = new byte[4];
Buffer.BlockCopy(buffer, 12, proxyFromAddrBuffer, 0, 4);
int sendFromPort = BitConverter.ToInt32(buffer, 16);
SIPEndPoint proxySendFrom = new SIPEndPoint((SIPProtocolsEnum)proxyProtocol, new IPEndPoint(new IPAddress(proxyFromAddrBuffer), sendFromPort));
//SIPProtocolsEnum protocol = SIPProtocolsType.GetProtocolTypeFromId(BitConverter.ToInt32(buffer, 16));
//SIPProtocolsEnum protocol = SIPProtocolsEnum.udp;
NATKeepAliveMessage natKeepAliveMsg = new NATKeepAliveMessage(proxySendFrom, new IPEndPoint(sendToAddress, sendToPort));
return(natKeepAliveMsg);
}
else
{
return(null);
}
}
private void NatKeepAliveChannelMessageReceived(SIPChannel sipChannel, SIPEndPoint remoteEndPoint, byte[] buffer)
{
try
{
NATKeepAliveMessage keepAliveMessage = NATKeepAliveMessage.ParseNATKeepAliveMessage(buffer);
if (keepAliveMessage != null)
{
if (keepAliveMessage.LocalSIPEndPoint.Protocol == SIPProtocolsEnum.udp)
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "Relaying NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
m_sipTransport.SendRaw(keepAliveMessage.LocalSIPEndPoint, new SIPEndPoint(keepAliveMessage.RemoteEndPoint), m_sendBuffer);
}
else
{
// For connection oriented protocols check whether a connection exists. NAT keep alives shouldn't cause a connection to be initiated.
SIPChannel sendFromChannel = m_sipTransport.FindSIPChannel(keepAliveMessage.LocalSIPEndPoint);
if (sendFromChannel != null && sendFromChannel.IsConnectionEstablished(keepAliveMessage.RemoteEndPoint))
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "Relaying NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
m_sipTransport.SendRaw(keepAliveMessage.LocalSIPEndPoint, new SIPEndPoint(keepAliveMessage.RemoteEndPoint), m_sendBuffer);
}
else
{
FireSIPMonitorLogEvent(new SIPMonitorConsoleEvent(SIPMonitorServerTypesEnum.NATKeepAlive, SIPMonitorEventTypesEnum.NATKeepAliveRelay, "No established connection was found to relay NAT keep-alive from proxy socket " + keepAliveMessage.LocalSIPEndPoint + " to " + keepAliveMessage.RemoteEndPoint + ".", null));
}
}
}
}
catch (Exception excp)
{
logger.Error("Exception NatKeepAliveChannelMessageReceived. " + excp.Message);
}
}
public void ReverseMessageTest()
{
Console.WriteLine(System.Reflection.MethodBase.GetCurrentMethod().Name);
string sendToAddress = "192.168.1.1";
int sendToPort = 3455;
string sendFromAddress = "192.168.1.2";
int sendFromPort = 3244;
NATKeepAliveMessage keepAliveMsg = new NATKeepAliveMessage(SIPEndPoint.ParseSIPEndPoint(sendToAddress + ":" + sendToPort), new IPEndPoint(IPAddress.Parse(sendFromAddress), sendFromPort));
byte[] buffer = keepAliveMsg.ToBuffer();
Assert.IsTrue(buffer != null && buffer.Length == 20, "The byte buffer produced for the NATKeepAliveMessage is invalid.");
NATKeepAliveMessage rtnMsg = NATKeepAliveMessage.ParseNATKeepAliveMessage(buffer);
Assert.IsNotNull(rtnMsg, "The NATKeepAliveMessage could not be parsed from the buffer.");
Assert.IsTrue(rtnMsg.RemoteEndPoint.ToString() == keepAliveMsg.RemoteEndPoint.ToString(), "The sent and returned sendto sockets were different.");
Assert.IsTrue(rtnMsg.LocalSIPEndPoint.ToString() == keepAliveMsg.LocalSIPEndPoint.ToString(), "The sent and returned sendfrom sockets were different.");
}
public void ReverseMessageTest()
{
Console.WriteLine(System.Reflection.MethodBase.GetCurrentMethod().Name);
string sendToAddress = "192.168.1.1";
int sendToPort = 3455;
string sendFromAddress = "192.168.1.2";
int sendFromPort = 3244;
NATKeepAliveMessage keepAliveMsg = new NATKeepAliveMessage(SIPEndPoint.ParseSIPEndPoint(sendToAddress + ":" + sendToPort), new IPEndPoint(IPAddress.Parse(sendFromAddress), sendFromPort));
byte[] buffer = keepAliveMsg.ToBuffer();
Assert.IsTrue(buffer != null && buffer.Length == 20, "The byte buffer produced for the NATKeepAliveMessage is invalid.");
NATKeepAliveMessage rtnMsg = NATKeepAliveMessage.ParseNATKeepAliveMessage(buffer);
Assert.IsNotNull(rtnMsg, "The NATKeepAliveMessage could not be parsed from the buffer.");
Assert.IsTrue(rtnMsg.RemoteEndPoint.ToString() == keepAliveMsg.RemoteEndPoint.ToString(), "The sent and returned sendto sockets were different.");
Assert.IsTrue(rtnMsg.LocalSIPEndPoint.ToString() == keepAliveMsg.LocalSIPEndPoint.ToString(), "The sent and returned sendfrom sockets were different.");
}
/// <summary>
/// This event handler is fired when the SIP Registrar wants to send a NATKeepAlive message to a user contact to make an attempt to keep the connection
/// open through the user's NAT server. In this case the NATKeepAlive messages are forwarded onto the NATKeepAlive relay which requests the SIPTransport
/// layer to multiplex a 4 byte null payload onto one of its sockets and send to the specified agent. A typical scenario would have the SIP Registrar
/// firing this event every 15s to send the null payloads to each of its registered contacts.
/// </summary>
private void SendNATKeepAlive(NATKeepAliveMessage keepAliveMessage) {
try {
byte[] buffer = keepAliveMessage.ToBuffer();
m_natKeepAliveSender.Send(buffer, buffer.Length, m_natKeepAliveRelaySocket);
}
catch (Exception natSendExcp) {
logger.Warn("Exception SendNATKeepAlive " + keepAliveMessage.RemoteEndPoint + ". " + natSendExcp.Message);
}
}