#sorted
AX25_WINDOW	1
AX25_T1		2
AX25_N2		3
AX25_T3		4
AX25_T2		5
AX25_BACKOFF	6
AX25_EXTSEQ	7
AX25_PIDINCL	8
AX25_IDLE	9
AX25_PACLEN	10
AX25_IAMDIGI	12

/* 13, 25, or 16409, depending on arch */
SO_BINDTODEVICE