Adds a STUNClient and extension to make consuming the RTP server reflexive address more convenient (#1460)

* Adds a STUNClient and extension to make consuming the RTP server reflexive address more convenient.

* Update src/net/RTP/RTPSession.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update src/net/STUN/STUNClient.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Use the timeout secodns in the stun client extension.

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: sipsorcery

examples/SIPExamples/SIPExamples.sln

@@ -47,10 +47,6 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SIPCallServer", "SIPCallSer
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "SIPCloudCallServer", "SIPCloudCallServer\SIPCloudCallServer.csproj", "{AC215797-8B94-2D46-A603-D4EAC8C8604A}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UserAgentClientWithStun", "UserAgentClientWithStun\UserAgentClientWithStun.csproj", "{DF234766-1556-47E7-E748-2A7441854647}"
-EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UserAgentServerWithStun", "UserAgentServerWithStun\UserAgentServerWithStun.csproj", "{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -325,30 +321,6 @@ Global
 		{AC215797-8B94-2D46-A603-D4EAC8C8604A}.Release|x64.Build.0 = Release|Any CPU
 		{AC215797-8B94-2D46-A603-D4EAC8C8604A}.Release|x86.ActiveCfg = Release|Any CPU
 		{AC215797-8B94-2D46-A603-D4EAC8C8604A}.Release|x86.Build.0 = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|x64.Build.0 = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Debug|x86.Build.0 = Debug|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|Any CPU.Build.0 = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|x64.ActiveCfg = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|x64.Build.0 = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|x86.ActiveCfg = Release|Any CPU
-		{DF234766-1556-47E7-E748-2A7441854647}.Release|x86.Build.0 = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|x64.Build.0 = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Debug|x86.Build.0 = Debug|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|Any CPU.Build.0 = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|x64.ActiveCfg = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|x64.Build.0 = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|x86.ActiveCfg = Release|Any CPU
-		{C130FDC0-A4DA-57DC-0E96-C9A4E36DDFCB}.Release|x86.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE

examples/SIPExamples/UserAgentClient/Program.cs

@@ -13,6 +13,7 @@
 //
 // Usage Examples:
 // set TURN_URL=turn:your.turn.server;user;password
+// set STUN_URL=stun:stun.l.google.com:19302
 // dotnet run -- 127.0.0.1:5080
 //
 // Author(s):
@@ -46,6 +47,7 @@ namespace demo;
 class Program
 {
     private const string TURN_SERVER_URL_ENV_VAR = "TURN_URL";
+    private const string STUN_SERVER_URL_ENV_VAR = "STUN_URL";
     private static readonly string DEFAULT_DESTINATION_SIP_URI = "sip:music@iptel.org";
     private const int TURN_ALLOCATION_TIMEOUT_SECONDS = 5;
 
@@ -65,10 +67,13 @@ static async Task Main(string[] args)
         Log = AddConsoleLogger(LogEventLevel.Debug);
 
         var turnServerUrl = Environment.GetEnvironmentVariable(TURN_SERVER_URL_ENV_VAR);
-
         TurnClient turnClient = !string.IsNullOrWhiteSpace(turnServerUrl) ?
             new TurnClient(turnServerUrl) : null;
 
+        var stunServerUrl = Environment.GetEnvironmentVariable(STUN_SERVER_URL_ENV_VAR);
+        STUNClient stunClient = !string.IsNullOrWhiteSpace(stunServerUrl) ?
+            new STUNClient(stunServerUrl) : null;
+
         SIPURI callUri = SIPURI.ParseSIPURI(DEFAULT_DESTINATION_SIP_URI);
         if (args?.Length > 0)
         {
@@ -105,6 +110,10 @@ static async Task Main(string[] args)
         {
             await rtpSession.AudioStream.UseTurn(rtpSession, turnClient, default, TURN_ALLOCATION_TIMEOUT_SECONDS);
         }
+        else if (stunClient != null)
+        {
+            await rtpSession.AudioStream.UseStun(stunClient, default, Log);
+        }
 
         var offerSDP = rtpSession.CreateOffer(preferIPv6 ? IPAddress.IPv6Any : IPAddress.Any);