From mboxrd@z Thu Jan 1 00:00:00 1970 From: Flavio Leitner Subject: Re: Deliver skbs to intermediate interfaces, when using cascaded rx-handlers Date: Fri, 21 Feb 2014 14:10:35 -0300 Message-ID: <20140221171034.GA2488@localhost.localdomain> References: <20140221100158.GA19594@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org To: Tobias Waldekranz Return-path: Received: from mx1.redhat.com ([209.132.183.28]:22294 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755212AbaBURKk (ORCPT ); Fri, 21 Feb 2014 12:10:40 -0500 Content-Disposition: inline In-Reply-To: <20140221100158.GA19594@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Feb 21, 2014 at 11:01:58AM +0100, Tobias Waldekranz wrote: > I have a system with the following configuration: > > * eth0 is a regular Ethernet MAC, connected to a hardware switch. > * port[1-4] are the in-kernel representation of the switch. > * team0 is a regular team-interface which bonds port1 and port2. > > +-------+ > | team0 | > +---+---+ > | > +----+----+ > | | > +---+---+ +---+---+ +-------+ +-------+ > | port1 | | port2 | | port3 | | port4 | > +---+---+ +---+---+ +---+---+ +---+---+ > | | | | > +---------+----+----+---------+ > | > +---+---+ > | eth0 | > +-------+ > > Both the switch and the team driver attaches rx-handlers to their > lower layers. The problem is that team expects LACP frames that > are intercepted by team0, to also be delivered to the port interface > by __netif_receive_skb_core (in the final iteration of the registered > protocols). However in this case, when two rx-handlers are cascaded, > the skb will be delivered to eth0, since that is the original device > (orig_dev). Indeed. It is not possible to update orig_dev, so it is stuck on eth0 regardless of all the stacked interfaces. > There are a few ways this can be solved as far as i can see: > > 1. Introduce a new rx-handler return code that specifies that > skb->dev has been altered, like RX_HANDLER_ANOTHER, and that we > also want to change orig_dev to this new device. But then you need to know which rx-handler will run next, because the orig_dev might still be implicit wanted. > 2. Change the switch driver to return RX_HANDLER_CONSUMED and then > queue the skb all over again, though I am afraid that this will eat > some cycles. Before queue again, you need to update skb->dev, right? This seems similar to (1). > 3. Keep track of all traversed interfaces and change the final > protocol iteration to deliver the skb to all intermediate devices. That's what I thought too. fbl