Subject: Re: [PATCH] bridge: Remove BR_PROXYARP flooding check code

From: Stephen Hemminger <[email-masked]>
Date: Tue, 9 Dec 2014 14:21:58 -0800

On Mon,  8 Dec 2014 17:27:40 +0200
Jouni Malinen <[email-masked]> wrote:

> From: Kyeyoon Park <[email-masked]>
> 
> Because dropping broadcast packets for IEEE 802.11 Proxy ARP is more
> selective than previously thought, it is better to remove the direct
> dropping logic in the bridge code in favor of using the netfilter
> infrastructure to provide more control on which frames get dropped. This
> code was added in commit 958501163ddd ("bridge: Add support for IEEE
> 802.11 Proxy ARP").
> 
> Signed-off-by: Kyeyoon Park <[email-masked]>
> Signed-off-by: Jouni Malinen <[email-masked]>
> ---
>  net/bridge/br_forward.c | 4 ----
>  1 file changed, 4 deletions(-)
> 
> diff --git a/net/bridge/br_forward.c b/net/bridge/br_forward.c
> index f96933a..8a025a7 100644
> --- a/net/bridge/br_forward.c
> +++ b/net/bridge/br_forward.c
> @@ -185,10 +185,6 @@ static void br_flood(struct net_bridge *br, struct sk_buff *skb,
>  		if (unicast && !(p->flags & BR_FLOOD))
>  			continue;
>  
> -		/* Do not flood to ports that enable proxy ARP */
> -		if (p->flags & BR_PROXYARP)
> -			continue;
> -
>  		prev = maybe_deliver(prev, p, skb, __packet_hook);
>  		if (IS_ERR(prev))
>  			goto out;

Aren't you at risk of duplicate ARP responses in some cases.
You can't assume user will run netfilter.