Re: [B.A.T.M.A.N.] [PATCH] batman-adv: Fixing wrap-around bug in vis

["Linus Lüssing" <linus.luessing@web.de>]

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Sorry, typo there, has to be ">=" and not "<=" of coures. My
fault.

On Thu, Mar 11, 2010 at 10:19:06PM +0100, Linus Lüssing wrote:
> When the seqno for a vis packet had a wrap around from i.e. 255 to 0,
> add_packet() would falsely claim the older packet with the seqno 255 as
> newer as the one with the seqno of 0 and would therefore ignore the new
> packet. This happens with all following vis packets until the old vis
> packet expires after 180 seconds timeout. This patch fixes this issue
> and gets rid of these highly undesired 3min. breaks for the vis-server.
> 
> Signed-off-by: Linus Lüssing <linus.luessing@web.de>
> ---
>  batman-adv-kernelland/vis.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/batman-adv-kernelland/vis.c b/batman-adv-kernelland/vis.c
> index fa8a487..5735a6a 100644
> --- a/batman-adv-kernelland/vis.c
> +++ b/batman-adv-kernelland/vis.c
> @@ -213,7 +213,8 @@ static struct vis_info *add_packet(struct vis_packet *vis_packet,
>  	old_info = hash_find(vis_hash, &search_elem);
>  
>  	if (old_info != NULL) {
> -		if (vis_packet->seqno - old_info->packet.seqno <= 0) {
> +		if (vis_packet->seqno - old_info->packet.seqno
> +		    <= 1 << 7 * sizeof(vis_packet->seqno)) {
>  			if (old_info->packet.seqno == vis_packet->seqno) {
>  				recv_list_add(&old_info->recv_list,
>  					      vis_packet->sender_orig);
> -- 
> 1.7.0
> 

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