Kamailio can execute managed code assemblies via app_mono module:

• http://kamailio.org/docs/modules/devel/modules/app_mono.html

The C# API exported by Kamailio to the embedded Mono interpreter is defined in SR.cs file located in source tree modules/app_mono/lib/SR.cs.

To compile SR.cs to a library, use:

gmcs -t:library SR.cs

This will generate the file SR.dll. To link your C# file to it, use:

$ gmcs -r:SR.dll MyFile.cs

The API is stored in a namespace, named SR. The several classes offer access to internal Kamailio functionalities via public static functions.

public extern static string APIVersion();

Return API version string.

public extern static void Log(int level, string text);

Write a message via Kamailio logging system to specified log level.

public extern static void Err(string text);

Write a message via Kamailio logging system to error log level.

public extern static void Dbg(string text);

Write a message via Kamailio logging system to debug log level.

public extern static int ModF(string text);

Execute the function named by the value of parameter 'text' exported by a Kamailio module. It has to be a function with no parameters.

public extern static string GetS(string pvn);

Get the string value of a pseudo-variable.

public extern static int GetI(string pvn);

Get the integer value of a pseudo-variable.

public extern static int SetS(string pvn, string val);

Set the pseudo-variable to a string value.

public extern static int SetI(string pvn, int val);

Set the pseudo-variable to an integer value.

public extern static int Unset(string pvn);

Unset the pseudo-variable (like assigning $null in kamailio.cfg).

public extern static int IsNull(string pvn);

Return true if the pseudo-variable is null.

public extern static int Append(string hv);

Add a header to the end of the headers list. The parameter must be full header, including name, body header and ending '\r\n'.

public extern static int Remove(string name);

Remove all headers matching the name.

public extern static int Insert(string hv);

Add a header to the beginning of the headers list. The parameter must be full header, including name, body header and ending '\r\n'.

public extern static int AppendToReply(string hv);

Add a header to the headers list for local reply. The parameter must be full header, including name, body header and ending '\r\n'.

A basic example of C# application using SR API:

using SR;
 
namespace MySRTest {
        class Test {
                static int Main(string[] args) {
                        SR.Core.Log(1, "Kamailio API Version: " + SR.Core.APIVersion() + "\n");
                        if (args.Length == 1) {
                                SR.Core.Log(1, "Parameter from Kamailio config:"
                                        + args[0] + "\n");
                        }
                        SR.Core.Dbg("Request URI is: " + SR.PV.GetS("$ru") + "\n");
                        SR.PV.SetS("$rU", "123");
                        SR.HDR.AppendToReply("My-Mono-Hdr: ok\r\n");
                        SR.Core.ModF("sl_reply_error");
                        return 1;
                }
        }
}