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List:       netfilter-devel
Subject:    questions about connection tracking
From:       "jump lee" <zomby_cn () hotmail ! com>
Date:       2002-08-27 1:29:06
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in "linux netfilter hacking howto" rusty said "the nfct field in the skb is 
a pointer to inside the struct ip_conntrack, at one of the infos[] array." i 
am wondering how it works. there are my questions:

1.when nfct field is set?
2.what's the relationship between nfct and connection states?
3.when i read tcp connection tracking code, i found it just set the 
proto.tcp.state field in the struct ip_conntrack, but when the infos[] is 
set?
4.in __ip_conntrack_get, the function just use nfct to get the state. i 
really do not understand the code!! why can "*ctinfo = nfct - ct->infos;" 
get the state?
5.i do not understand the usage of struct nf_conntrack. for example, in 
__ip_conntrack_get,
            struct ip_conntrack *ct= (struct ip_conntrack *)nfct->master;
  we can change the pointer master to struct ip_conntrack * , why? what is 
the field use meaning? what is the usage of pointer destroy?

thanks for you all!!



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