netdev - Re: [RFC] net/core: Delay neighbor only if it has been used after confirmed

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Date:	Tue, 15 Sep 2009 12:07:26 +0200
From:	Jens Rosenboom <jens@...one.net>
To:	David Miller <davem@...emloft.net>
Cc:	Linux Network Developers <netdev@...r.kernel.org>,
	YOSHIFUJI Hideaki <yoshfuji@...ux-ipv6.org>
Subject: Re: [RFC] net/core: Delay neighbor only if it has been used after
 confirmed

On Thu, 2009-09-10 at 18:21 +0200, Jens Rosenboom wrote:
> On Wed, 2009-09-02 at 21:22 +0900, YOSHIFUJI Hideaki wrote:
> [...]
> > And, this "if" for REACHABLE->DELAY may be completely needless.
> > Timer in REACHABLE is only for state transition for toward REACHABLE
> > or STALE.
> 
> I did some testing with the following patch, which works fine for me, so
> I propose this one now instead of my previous one. I still have no real
> idea about the non-IPv6 implications of this, though.
> 
> ---
> 
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index e587e68..f61926f 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -819,13 +819,6 @@ static void neigh_timer_handler(unsigned long arg)
>  				   neigh->confirmed + neigh->parms->reachable_time)) {
>  			NEIGH_PRINTK2("neigh %p is still alive.\n", neigh);
>  			next = neigh->confirmed + neigh->parms->reachable_time;
> -		} else if (time_before_eq(now,
> -					  neigh->used + neigh->parms->delay_probe_time)) {
> -			NEIGH_PRINTK2("neigh %p is delayed.\n", neigh);
> -			neigh->nud_state = NUD_DELAY;
> -			neigh->updated = jiffies;
> -			neigh_suspect(neigh);
> -			next = now + neigh->parms->delay_probe_time;
>  		} else {
>  			NEIGH_PRINTK2("neigh %p is suspected.\n", neigh);
>  			neigh->nud_state = NUD_STALE;
> 

Hi David, what are your thoughts on this one? There is IMHO a real bug
to fix, namely sending tons of repeated neighbor solicitations when
there is no actual traffic to be sent, so this should qualify to go into
2.6.32. Do you want to wait for further comments or should I submit this
for net-2.6 so it can get some testing?


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