sysctl_sbp_verify
static int sysctl_sbp_verify(SYSCTLFN_PROTO, int lower, int upper);
return sysctl_sbp_verify(SYSCTLFN_CALL(rnode), 0, FWSPD_S400);
return sysctl_sbp_verify(SYSCTLFN_CALL(rnode), -1, 1);