various.go

// ValidAS takes an int and returns true if valid or false if not.
func ValidAS(a int) bool {
	// we'll make some basic oversimplicifcations and include unassigned space as valid for convienience.
	// not valid yet, but more valid than doc and reserved space.
	switch {
	case a == 0:
		return false
	case a > 1 && a < 64496:
		// current valid 2byte range that makes up most of the internet.
		return true
	case a >= 64496 && a <= 65535:
		// documentation and reserved
		return false
	case a > 65536 && a <= 131071:
		// reserved bottom end of 4byte range
		return false
	case a >= 131072 && a < 397213:
		// valid 4byte range
		return true
	case a >= 397213:
		// end of 4byte range and up.
		return false
	}
	return true
}