code: function convToNum(ipstr) {
      let ret = 0;
      let mul = 256*256*256;
      ipstr.split('.').forEach((numstr)=>{
          ret += parseInt(numstr)*mul;
          mul >>= 8;
      });
      return ret;
  }
docs: Convert to number value from string IP address
  @param {string} ipstr : string IP address
  @return {number} number value of IP address