Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Fix out-of-order fragmentation support

[Marek Lindner <mareklindner@neomailbox.ch>]

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On Monday 26 May 2014 17:21:39 Sven Eckelmann wrote:
> batadv_frag_insert_packet was unable to handle out-of-order packets because
> it dropped them directly. This is caused by the way the fragmentation lists
> is checked for the correct place to insert a fragmentation entry.
> 
> The fragmentation code keeps the fragments in lists. The fragmentation
> entries are kept in descending order of sequence number. The list is
> traversed and each entry is compared with the new fragment. If the current
> entry has a smaller sequence number than the new fragment then the new one
> has to be inserted before the current entry. This ensures that the list is
> still in descending order.
> 
> An out-of-order packet with a smaller sequence number than all entries in
> the list still has to be added to the end of the list. The used hlist has
> no information about the last entry in the list inside hlist_head and thus
> the last entry has to be calculated differently. Currently the code assumes
> that the iterator variable of hlist_for_each_entry can be used for this
> purpose after the hlist_for_each_entry finished. This is obviously wrong
> because the iterator variable is always NULL when the list was completely
> traversed.
> 
> Instead the information about the last entry has to be stored in a different
> variable.
> 
> This problem was introduced in 9b3eab61754d74a93c9840c296013fe3b4a1b606
> ("batman-adv: Receive fragmented packets and merge").
> 
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> Patch was only build-tested
> ---
>  fragmentation.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)

Applied in revision 4c525d3.

Thanks,
Marek

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