From mboxrd@z Thu Jan  1 00:00:00 1970
From: nicho <fessboy@tom.com>
Subject: how to parse options?
Date: Fri, 21 Nov 2003 22:37:43 +0800
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hi:
     #iptables -t nat -A POSTROUTING -o eth1 -s xxxxx/24 -j SNAT
--to-source yyyyy
    As we know, in kernel there is a structure called multi_range. When
we do nat, we choose a proper IP from the multi_range, and a proper port
if necessory. My question is, how multi_range is set into kernel, and
how option '--to-source' is parsed?
    By the way, I'm confused at getsockopt(... SO_GET_ENTRY...) . As the
name implies, we want to get entry info from kernel, but why it dose
copy data from user level to kernel level indeed. What does it do at all?