hi,all
we can define variable in nwfilter xml file,  and assign value in domain xml .
i add a new attribute , if the  value is constant, it works .
if it is variable,  it will product wrong iptables rules.
i want to know  how libvirt process variable?  where is the difference  between processing constant and variable?
when it is variable, if  validator function is needed?
 
thanks