Google Authenticator iRule Verification

I know this thread is old, but I just went through the same process trying to get the otp iRule working as normal without warnings.

The problematic expr statements contain string concatenation used to generate hex values for bitwise operations. It wont work as expected if you simply wrap that in curly brackets, so I just break it up a little. For example this becomes this...

  set o [expr 0x$k ^ 0x5C ]
  set i [expr 0x$k ^ 0x36 ]

  set kh 0x$k
  set o [expr {$kh ^ 0x5C} ]
  set i [expr {$kh ^ 0x36} ]