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From: Felix Fietkau <nbd@openwrt•org>
To: Stephen Hemminger <stephen@networkplumber•org>
Cc: netdev@vger•kernel.org
Subject: Re: [PATCH net] bridge: allow receiption on disabled port
Date: Thu, 10 Oct 2013 22:56:33 +0200	[thread overview]
Message-ID: <52571481.5010907@openwrt.org> (raw)
In-Reply-To: <20131010133646.1bdd42c1@nehalam.linuxnetplumber.net>

On 2013-10-10 10:36 PM, Stephen Hemminger wrote:
> On Thu, 10 Oct 2013 14:52:50 +0200
> Felix Fietkau <nbd@openwrt•org> wrote:
> 
>> When an ethernet device is enslaved to a bridge, and the bridge STP
>> detects loss of carrier (or operational state down), then normally
>> packet receiption is blocked.
>> 
>> This breaks control applications like WPA which maybe expecting to
>> receive packets to negotiate to bring link up. The bridge needs to
>> block forwarding packets from these disabled ports, but there is no
>> hard requirement to not allow local packet delivery.
>> 
>> Signed-off-by: Stephen Hemminger <stephen@networkplumber•org>
>> Signed-off-by: Felix Fietkau <nbd@openwrt•org>
> 
> No. This will cause duplicate packets to be delivered.
How? I haven't observed any duplications in my tests with this patch.

> If doing a link layer protocol like WPA then it should be done directly
> on the underlying device, not the bridge itself.
When the ETH_P_PAE protocol is set for the packet socket inside
wpa_supplicant, the bridge steals all packets before the protocol
handler gets them.
In __netif_receive_skb_core, only ptype_all gets processed before the rx
handler, not ptype_base.


- Felix

  reply	other threads:[~2013-10-10 20:56 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-10 12:52 [PATCH net] bridge: allow receiption on disabled port Felix Fietkau
2013-10-10 20:36 ` Stephen Hemminger
2013-10-10 20:56   ` Felix Fietkau [this message]
2013-10-10 21:52     ` Stephen Hemminger
2013-10-10 22:08       ` Felix Fietkau
2013-10-11  2:35     ` Stephen Hemminger
2013-10-11 10:18       ` Felix Fietkau
2013-10-11 15:10         ` Stephen Hemminger

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