CAN_J1939
#ifdef CAN_J1939
#define SOL_CAN_J1939 (SOL_CAN_BASE + CAN_J1939)
MODULE_ALIAS("can-proto-" __stringify(CAN_J1939));
.protocol = CAN_J1939,
sk->sk_protocol = CAN_J1939;
skb->sk->sk_protocol != CAN_J1939)