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From: Nicolas Dichtel <nicolas.dichtel@6wind•com>
To: netdev <netdev@vger•kernel.org>
Cc: David Miller <davem@davemloft•net>,
	Stephen Hemminger <shemminger@vyatta•com>
Subject: rp_filter backward compatibility
Date: Mon, 30 Aug 2010 17:25:22 +0200	[thread overview]
Message-ID: <4C7BCD62.3030805@6wind.com> (raw)

I'm surprised by the commit 27fed4175acf81ddd91d9a4ee2fd298981f60295 (ip: fix 
logic of reverse path filter sysctl). This commit breaks backward compatibility.
I know that logic was wrong, but for years it was mandatory to set both 
all.rp_filter and <device>.rp_filter to enable it, ie setting only all.rp_filter 
had no consequences. Now, when all.rp_filter is enabled, RPF is enabled for all 
interfaces.
Help of Kconfig explains:

                                                                 "To turn
           rp_filter on use:

           echo 1 > /proc/sys/net/ipv4/conf/<device>/rp_filter
            *and*
           echo 1 > /proc/sys/net/ipv4/conf/all/rp_filter"

At least, one of this action should be done:
  - fixing help (Documentation/networking/ip-sysctl.txt is up to date)
  - reverting the patch (this will force to set all.rp_filter to 3 if some 
interfaces use loose mode and some others strict mode)

What is your opinion?

Regards,
Nicolas

             reply	other threads:[~2010-08-30 15:25 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-30 15:25 Nicolas Dichtel [this message]
2010-08-30 16:47 ` rp_filter backward compatibility David Miller
2010-08-31 15:50   ` Nicolas Dichtel
2010-09-01 21:30     ` David Miller

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