Date: Thu, 23 Feb 2017 13:48:41 +0000 From: Ben Woods <woodsb02@gmail.com> To: Alexandre Snarskii <snar@snar.spb.ru>, freebsd-net <freebsd-net@freebsd.org> Subject: Re: tap(4): half-duplex and zero-speed ? Message-ID: <CAOc73CC5uKn2tFXeSL%2B3o6jdai9WsS8F7idyKzDXL_qCS=5TYA@mail.gmail.com> In-Reply-To: <20170223124258.GA80687@staff.retn.net> References: <20170223124258.GA80687@staff.retn.net>
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On Thu, 23 Feb 2017 at 8:43 pm, Alexandre Snarskii <snar@snar.spb.ru> wrote: > > Hi! > > Long story short: if you try to aggregate tap(4) devices into lacp-based > lagg(4), aggregate will fail to negotiate lacp with remote end and will not > be able to pass traffic. > > Root cause: lacp code requires underlying interface to be full-duplex > (else it will not participate in lacp negotiation at all[1]) and have > non-zero speed (else it can not be selected as active aggregator[2], > and so if tap is the only lagg member - aggregate will not become active). > > Patch can be as trivial as: > > --- sys/net/if_tap.c.orig 2017-02-21 21:02:04.460053000 +0300 > +++ sys/net/if_tap.c 2017-02-21 21:02:12.580696000 +0300 > @@ -617,7 +617,7 @@ > dummy = ifmr->ifm_count; > ifmr->ifm_count = 1; > ifmr->ifm_status = IFM_AVALID; > - ifmr->ifm_active = IFM_ETHER; > + ifmr->ifm_active = IFM_ETHER | IFM_1000_T | > IFM_FDX; > if (tp->tap_flags & TAP_OPEN) > ifmr->ifm_status |= IFM_ACTIVE; > ifmr->ifm_current = ifmr->ifm_active; > > > [1]: > https://svnweb.freebsd.org/base/head/sys/net/ieee8023ad_lacp.c?revision=312678&view=markup#l483 > [2]: > https://svnweb.freebsd.org/base/head/sys/net/ieee8023ad_lacp.c?revision=312678&view=markup#l983 Hi Alexandre, Thanks for taking the time to look into the cause of this and for your clear explanation of the problem. Would you mind please submitting a bug report so this doesn't get forgotten? https://bugs.freebsd.org/ Regards, Ben -- -- From: Benjamin Woods woodsb02@gmail.com
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