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Note to use binary operator
if a binary operator has a floating point operand, the computation is done using floating point arithmetic and the result is a floating point value. If it has a long operand, the computation is done using long integer arithmetic, and the result is a long . Operands that are smaller than an int (such as bool and char ) are converted to int before the operator is applied.

Different between RAW and PF_PACKET socket
The former will not return the link layer header