// NAT METHODS
private static IceCandidate GatherNAActiveCandidate(IPAddress localIPAddress, IceCandidate baseCandidate)
{
// exactly the same procedure like GatherSRActiveCandidate()
// derived from passive NAT assisted candidate
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
Socket activeConnectingSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
// here is no bind, because active candidates don't have to be physically allocated here (allocation in connectivity checks)
/* RFC 6544 (ICE TCP), Section 3:
In the case of active candidates, both IP
address and port are present, but the port is meaningless (it is
there only for making encoding of active candidates consistent with
the other candidate types and is ignored by the peer). As a
consequence, active candidates do not need to be physically allocated
at the time of address gathering. Rather, the physical allocations,
which occur as a consequence of a connection attempt, occur at the
time of the connectivity checks.
*/
// create candidate object
IpAddressPort activeIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, baseCandidate.addr_port.ipaddr, 0); // port is meaningless
IceCandidate activeCandidate = new IceCandidate(activeIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
activeCandidate.cand_type = CandType.tcp_nat;
activeCandidate.rel_addr_port = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, 0); // port is meaningless
activeCandidate.activeConnectingSocket = activeConnectingSocket;
// TCP Type
activeCandidate.tcpType = TcpType.Active;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("active");
activeCandidate.extension_list.Add(iceExtension);
return activeCandidate;
}
private static IceCandidate GatherNAPassiveCandidate(IPAddress localIPAddress)
{
// local endpoint
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
// only one listening socket, because there is no need to use a STUN server. We get the IP and Port from the NAT using UPnP
Socket passiveListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
passiveListeningSocket.Bind(localEndpoint);
// update localEndpoint with binded Port
localEndpoint = (IPEndPoint)passiveListeningSocket.LocalEndPoint;
// check if UPnP is available
UPnP upnp = new UPnP();
bool foundUPnPDevice = false;
try
{
foundUPnPDevice = upnp.Discover(localIPAddress);
}
catch (Exception e)
{
//Console.WriteLine(e.Message);
return null;
}
// IPEndPoint for public mapping
IPEndPoint publicMapping = null;
// found UPnP internet gateway device?
if (foundUPnPDevice)
{
// try to get public IP and to add a port mapping
try
{
string publicIP = upnp.GetExternalIP().ToString();
// we can use the local Port for the public NAT port mapping too
bool addedPortMapping = upnp.AddPortMapping((ushort)localEndpoint.Port, (ushort)localEndpoint.Port, ProtocolType.Tcp, "RELOAD ICE TCP Port mapping");
if (addedPortMapping && !string.IsNullOrEmpty(publicIP))
{
publicMapping = new IPEndPoint(IPAddress.Parse(publicIP), localEndpoint.Port);
}
else
return null;
}
catch (Exception e)
{
//Console.WriteLine(e.Message);
return null;
}
}
// no UPnP IGD found
else
return null;
// got public mapping?
if (publicMapping == null)
return null;
// save data in candidate object
IpAddressPort passiveIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, publicMapping.Address, (ushort)publicMapping.Port);
IceCandidate passiveCandidate = new IceCandidate(passiveIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
passiveCandidate.cand_type = CandType.tcp_nat;
passiveCandidate.rel_addr_port = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
passiveCandidate.passiveListeningSocket = passiveListeningSocket;
// TCP Type
passiveCandidate.tcpType = TcpType.Passive;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("passive");
passiveCandidate.extension_list.Add(iceExtension);
return passiveCandidate;
}
private static IceCandidate GatherSRPassiveCandidate(IPAddress localIPAddress)
{
// local endpoint
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
// listening socket
Socket passiveListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
passiveListeningSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
passiveListeningSocket.Bind(localEndpoint);
// update localEndpoint with binded Port
localEndpoint = (IPEndPoint)passiveListeningSocket.LocalEndPoint;
// STUN socket
Socket passiveSTUNSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
passiveSTUNSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
passiveSTUNSocket.Bind(localEndpoint);
// get defined STUN servers
List<IPEndPoint> definedSTUNServers = GetDefinedSTUNServers();
// servers defined?
if (definedSTUNServers.Count > 0)
{
// use first server
IPEndPoint STUNEndPoint = definedSTUNServers[0];
// try to connect
try
{
passiveSTUNSocket.Connect(STUNEndPoint);
}
catch (Exception e1)
{
//Console.WriteLine(e1.Message);
// use second STUN server, if defined
if (definedSTUNServers.Count == 2)
{
STUNEndPoint = definedSTUNServers[1];
// try to connect
try
{
passiveSTUNSocket.Connect(STUNEndPoint);
}
catch (Exception e2)
{
//Console.WriteLine(e2.Message);
// could not establish a connection to a STUN server
return null;
}
}
}
}
// no STUN servers defined
else
return null;
// get public mapping
IPEndPoint publicMapping = GetPublicMapping(passiveSTUNSocket);
// save data in candidate object
IpAddressPort passiveIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, publicMapping.Address, (ushort)publicMapping.Port);
IceCandidate passiveCandidate = new IceCandidate(passiveIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
passiveCandidate.cand_type = CandType.tcp_srflx;
passiveCandidate.rel_addr_port = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
passiveCandidate.passiveListeningSocket = passiveListeningSocket;
passiveCandidate.passiveSTUNSocket = passiveSTUNSocket;
// TCP Type
passiveCandidate.tcpType = TcpType.Passive;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("passive");
passiveCandidate.extension_list.Add(iceExtension);
return passiveCandidate;
}
private static IceCandidate GatherSRSOCandidate(IPAddress localIPAddress)
{
// local endpoint
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
// listening socket
Socket soListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soListeningSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soListeningSocket.Bind(localEndpoint);
// update localEndpoint with binded Port
localEndpoint = (IPEndPoint)soListeningSocket.LocalEndPoint;
// connecting socket
Socket soConnectingSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soConnectingSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soConnectingSocket.Bind(localEndpoint);
// STUN1 socket
Socket soSTUN1Socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soSTUN1Socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soSTUN1Socket.Bind(localEndpoint);
// STUN2 socket
Socket soSTUN2Socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soSTUN2Socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soSTUN2Socket.Bind(localEndpoint);
// public mapping
IPEndPoint publicMapping = null;
// get defined STUN servers
List<IPEndPoint> definedSTUNServers = GetDefinedSTUNServers();
// no defined STUN servers
if (definedSTUNServers.Count == 0)
return null;
// only one STUN Server defined
// so we can't predict the port mapping for two successive outgoing connections
// what we can do here is to assume that the outgoing connections get the same port mapping
else if (definedSTUNServers.Count == 1)
{
// try to connect
try
{
soSTUN1Socket.Connect(definedSTUNServers[0]);
}
catch (Exception e)
{
//Console.WriteLine(e.Message);
// could not connect to STUN server
return null;
}
publicMapping = GetPublicMapping(soSTUN1Socket);
}
// two STUN servers defined
// here we can predict the port mapping for two successive outgoing connections
else if (definedSTUNServers.Count == 2)
{
// try to connect to first STUN server
try
{
// get first public mapping
soSTUN1Socket.Connect(definedSTUNServers[0]);
IPEndPoint mapping1 = GetPublicMapping(soSTUN1Socket);
// now try to connect to second STUN Server
try
{
soSTUN2Socket.Connect(definedSTUNServers[1]);
IPEndPoint mapping2 = GetPublicMapping(soSTUN2Socket);
// calculate difference between port mappings
int portDifference = mapping2.Port - mapping1.Port;
// IP will be the same, port will be adapted
publicMapping = new IPEndPoint(mapping2.Address, mapping2.Port + portDifference);
}
catch (Exception e)
{
//Console.WriteLine(e.Message);
// use first mapping and assume port mapping will be equal
publicMapping = mapping1;
}
}
catch (Exception e1)
{
//Console.WriteLine(e1.Message);
// could not connect to first STUN server
// try second, but then we can't predict port mapping, only assume the port mapping will be equal for next outgoing connection
try
{
soSTUN2Socket.Connect(definedSTUNServers[1]);
publicMapping = GetPublicMapping(soSTUN2Socket);
}
catch (Exception e2)
{
//Console.WriteLine(e2.Message);
// could not connect to first and second STUN Server
return null;
}
}
}
// got no public mapping
if (publicMapping == null)
return null;
// save data in candidate object
IpAddressPort soIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, publicMapping.Address, (ushort)publicMapping.Port);
IceCandidate soCandidate = new IceCandidate(soIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
soCandidate.cand_type = CandType.tcp_srflx;
soCandidate.rel_addr_port = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
soCandidate.soListeningSocket = soListeningSocket;
soCandidate.soConnectingSocket = soConnectingSocket;
soCandidate.soSTUN1Socket = soSTUN1Socket;
soCandidate.soSTUN2Socket = soSTUN2Socket;
// TCP Type
soCandidate.tcpType = TcpType.SO;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("so");
soCandidate.extension_list.Add(iceExtension);
return soCandidate;
}
private static IceCandidate GatherHostSOCandidate(IPAddress localIPAddress)
{
// local endpoint
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
// listening socket
Socket soListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soListeningSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soListeningSocket.Bind(localEndpoint);
// update localEndpoint with binded Port
localEndpoint = (IPEndPoint)soListeningSocket.LocalEndPoint;
// connecting socket
Socket soConnectingSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
soConnectingSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
soConnectingSocket.Bind(localEndpoint);
// save data in candidate object
IpAddressPort soIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
IceCandidate soCandidate = new IceCandidate(soIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
soCandidate.cand_type = CandType.tcp_host;
soCandidate.soListeningSocket = soListeningSocket;
soCandidate.soConnectingSocket = soConnectingSocket;
// TCP Type
soCandidate.tcpType = TcpType.SO;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("so");
soCandidate.extension_list.Add(iceExtension);
return soCandidate;
}
private static IceCandidate GatherHostPassiveCandidate(IPAddress localIPAddress)
{
// local endpoint
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
Socket passiveListeningSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
passiveListeningSocket.Bind(localEndpoint);
// update localEndpoint with binded Port
localEndpoint = (IPEndPoint)passiveListeningSocket.LocalEndPoint;
// save data in candidate object
IpAddressPort passiveIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
IceCandidate passiveCandidate = new IceCandidate(passiveIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
passiveCandidate.cand_type = CandType.tcp_host;
passiveCandidate.passiveListeningSocket = passiveListeningSocket;
// TCP Type
passiveCandidate.tcpType = TcpType.Passive;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("passive");
passiveCandidate.extension_list.Add(iceExtension);
return passiveCandidate;
}
// HOST METHODS
private static IceCandidate GatherHostActiveCandidate(IPAddress localIPAddress)
{
IPEndPoint localEndpoint = new IPEndPoint(localIPAddress, 0);
//Socket activeConnectingSocket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
//// here is no bind, because active candidates don't have to be physically allocated here (allocation in connectivity checks)
//activeConnectingSocket.Bind(localEndpoint); // TEST
/* RFC 6544 (ICE TCP), Section 3:
In the case of active candidates, both IP
address and port are present, but the port is meaningless (it is
there only for making encoding of active candidates consistent with
the other candidate types and is ignored by the peer). As a
consequence, active candidates do not need to be physically allocated
at the time of address gathering. Rather, the physical allocations,
which occur as a consequence of a connection attempt, occur at the
time of the connectivity checks.
*/
// save data in candidate object
IpAddressPort activeIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, localEndpoint.Address, (ushort)localEndpoint.Port);
IceCandidate activeCandidate = new IceCandidate(activeIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
activeCandidate.cand_type = CandType.tcp_host;
//activeCandidate.activeConnectingSocket = activeConnectingSocket; // TEST: in PerformCheck
// TCP Type
activeCandidate.tcpType = TcpType.Active;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("active");
activeCandidate.extension_list.Add(iceExtension);
return activeCandidate;
}
public static IceCandidate CreateBootstrapCandidate(IPAddress localIPAddress, int port)
{
// save data in candidate object
IpAddressPort bootstrapIpAddressPort = new IpAddressPort(AddressType.IPv4_Address, localIPAddress, (ushort)port);
IceCandidate bootstrapCandidate = new IceCandidate(bootstrapIpAddressPort, Overlay_Link.TLS_TCP_with_FH);
bootstrapCandidate.cand_type = CandType.tcp_bootstrap;
// TCP Type
bootstrapCandidate.tcpType = TcpType.Passive;
// TCP ICE extension
IceExtension iceExtension = new IceExtension();
iceExtension.name = Encoding.UTF8.GetBytes("tcptype");
iceExtension.value = Encoding.UTF8.GetBytes("passive");
bootstrapCandidate.extension_list.Add(iceExtension);
// set other preference and foundation
bootstrapCandidate.otherPreference = 8191;
bootstrapCandidate.foundation = ComputeFoundation(bootstrapCandidate);
return bootstrapCandidate;
}
public IceCandidate(IpAddressPort addr_port, Overlay_Link ol)
{
this.addr_port = addr_port;
this.priority = IceCandidate.NoICE_PRIORITY;
this.cand_type = CandType.tcp_host;
this.overlay_link = ol;
this.extension_list = new List<IceExtension>();
}
