Re: [B.A.T.M.A.N.] [PATCH 2/2] batman-adv: Avoid u32 overflow during gateway select

[Marek Lindner <mareklindner@neomailbox.ch>]

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On Tuesday, May 26, 2015 18:34:27 Sven Eckelmann wrote:
> From: Ruben Wisniewski <ruben@freifunk-nrw.de>
> 
> The gateway selection based on fast connections is using a single value
> calculated from the average tq (0-255) and the download bandwidth (in
> 100Kibit). The formula for the first step (tq ** 2 * 10000 * bandwidth)
> tends to overflow a u32 with low bandwidth settings like 50 [100KiBit]
> and a tq value of over 92.
> 
> Changing this to a 64 bit unsigned integer allows to support a
> bandwidth_down with up to ~2.8e10 [100KiBit] and a perfect tq of 255. This
> is ~6.6 times higher than the maximum possible value of the gateway
> announcement TVLV.
> 
> This problem only affects the non-default gw_sel_class 1.
> 
> Signed-off-by: Ruben Wisniewsi <ruben@vfn-nrw.de>
> [sven@narfation.org: rewritten commit message, changed to kernel type]
> Signed-off-by: Sven Eckelmann <sven@narfation.org>
> ---
> I am sending this because Ruben Wisniewski didn't fix the commit message
> (yet) and my earlier patch broke his proposed one.
> ---
>  net/batman-adv/gateway_client.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Applied in revision f63c54b.

Thanks,
Marek

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