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From: Jim Sansing <jjsansing@verizon.net>
To: Linux Network Development list <netdev@vger.kernel.org>
Subject: Comment on nf_queue NF_STOLEN patch
Date: Tue, 18 Oct 2011 15:08:29 -0400	[thread overview]
Message-ID: <4E9DCEAD.7070603@verizon.net> (raw)
In-Reply-To: <CAEuXFEy89F_=J_PJMSbQ1fDcOEkkpz2vucq3LcToi7rTcZHcDA@mail.gmail.com>

I have been working on a kernel module that registers with netfilter,
and I noticed that a patch was added to nf_queue that changed the
handling of return code NF_FILTER from 'do nothing' to 'free the skb'. 
I'm not sure which kernel version this went in, but the date of the
patch is Feb, 19, 2010.

Everything I have read about netfilter states that it is up to the
netfilter hook to free the skb if NF_STOLEN is returned.  The
implications of this patch from a hook programming perspective are:

1) If the skb is used after the return from the hook, it must be cloned.
2) The original skb must not be freed.

I suggest that a comment be added to include/linux/netfilter.h that says
explicitly the skb will be freed if NF_STOLEN is returned.


Later . . .   Jim

  reply	other threads:[~2011-10-18 20:51 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-14 19:18 Problem with ixgbe and TX locked on one cpu Paweł Staszewski
2011-10-18 18:57 ` Jesse Brandeburg
2011-10-18 19:08   ` Jim Sansing [this message]
2011-10-18 21:23     ` Comment on nf_queue NF_STOLEN patch Eric Dumazet
2011-10-18 21:34       ` Jim Sansing
2011-10-19  4:10         ` Eric Dumazet
2011-10-20 10:30           ` Pablo Neira Ayuso
2011-10-19  9:21   ` Problem with ixgbe and TX locked on one cpu Paweł Staszewski
2011-10-19  9:21   ` Paweł Staszewski

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