I am working on netfilter source. I see that there are some definations like

typedef __unsigned__ int __s32;

1- what does __signed__ mean? what is the difference from signed?
2- I can not find the corrosponding code of ...ipv4/netfilter/ip_tables.c in cvs.netfilter.org. 
Is in cvs.netfilter.org only userspace programs shown?

thanks,
-- 
Ozgur Akan