Added suspicious ICMP payload content

Fixes #7049

scripts/lua/modules/icmp_utils.lua

@@ -98,4 +98,14 @@ if(trace_script_duration ~= nil) then
   io.write(debug.getinfo(1,'S').source .." executed in ".. (os.clock()-clock_start)*1000 .. " ms\n")
 end
 
+function icmp_utils.is_suspicious_entropy(e_min, e_max)
+   local diff = e_max - e_min
+   
+   if((e_min < 5) or (e_max >= 6) or (diff > 0.2)) then
+      return true
+   else
+      return false
+   end
+end
+
 return icmp_utils