expose C core version string to C#
diff --git a/src/csharp/Grpc.Core/GrpcEnvironment.cs b/src/csharp/Grpc.Core/GrpcEnvironment.cs
index 034a66b..29a6ea7 100644
--- a/src/csharp/Grpc.Core/GrpcEnvironment.cs
+++ b/src/csharp/Grpc.Core/GrpcEnvironment.cs
@@ -53,6 +53,9 @@
         [DllImport("grpc_csharp_ext.dll")]
         static extern void grpcsharp_shutdown();
 
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern IntPtr grpcsharp_version_string();  // returns not-owned const char*
+
         static object staticLock = new object();
         static GrpcEnvironment instance;
 
@@ -164,6 +167,15 @@
         }
 
         /// <summary>
+        /// Gets version of gRPC C core.
+        /// </summary>
+        internal string GetCoreVersionString()
+        {
+            var ptr = grpcsharp_version_string();  // the pointer is not owned
+            return Marshal.PtrToStringAnsi(ptr);
+        }
+
+        /// <summary>
         /// Shuts down this environment.
         /// </summary>
         private void Close()
diff --git a/src/csharp/ext/grpc_csharp_ext.c b/src/csharp/ext/grpc_csharp_ext.c
index 048887b..0d2a74a 100644
--- a/src/csharp/ext/grpc_csharp_ext.c
+++ b/src/csharp/ext/grpc_csharp_ext.c
@@ -849,6 +849,11 @@
 
 typedef void(GPR_CALLTYPE *test_callback_funcptr)(gpr_int32 success);
 
+/* Version info */
+GPR_EXPORT char *GPR_CALLTYPE grpcsharp_version_string() {
+  return grpc_version_string();
+}
+
 /* For testing */
 GPR_EXPORT void GPR_CALLTYPE
 grpcsharp_test_callback(test_callback_funcptr callback) {