Removing the static flag on SocketOptions for avoidance of reading the Time Stamp Counter and altering the implementation to read an Environment variable.

Author: Rick Shaw

src/NetMQ/Core/Utils/OpCode.cs

@@ -11,7 +11,13 @@ internal static class Opcode
 
         public static bool Open()
         {
-            if (SocketOptions.DoNotUseRDTSC)
+            //Look for an environment variable: "NETQM_SUPPRESS_RDTSC" with a value of "TRUE"
+            // The application can set this environment variable when this code is running in a system where
+            // it is not desirable to read the processor's time stamp counter.
+            // While this is supported in modern CPUs, the technique used for allocating executable memory, copying OP Code
+            // for the read of the time stamp and invoking the OP Code can be detected as Malware by some anti-virus vendors.
+            var val = Environment.GetEnvironmentVariable("NETQM_SUPPRESS_RDTSC");
+            if ("TRUE".Equals(val, StringComparison.OrdinalIgnoreCase))
                 return false;
 #if NETSTANDARD1_1_OR_GREATER || NET471_OR_GREATER
             if (RuntimeInformation.ProcessArchitecture != Architecture.X86 &&

src/NetMQ/SocketOptions.cs

@@ -12,16 +12,6 @@ namespace NetMQ
     /// </summary>
     public class SocketOptions
     {
-        /// <summary>
-        /// If set, the time stamp counter is not read directly through opcode injection,
-        /// rather <see cref="System.Diagnostics.Stopwatch.GetTimestamp"/> is used.
-        /// When false, the time stamp counter is read by allocating a few bytes on the heap with
-        /// read/write/execute privilege. OpCode is copied to this allocated memory and invoked to read
-        /// the time stamp counter, (which is a register available on most modern CPUs). While this is
-        /// an accurate way to read the time stamp counter, because it injects code onto the heap, this
-        /// can be detected as a malware technique by some anti-virus defenders.
-        /// </summary>
-        public static bool DoNotUseRDTSC;
         /// <summary>
         /// The NetMQSocket that this SocketOptions is referencing.
         /// </summary>