Date: Wed, 22 Aug 2012 22:31:29 -0600 From: Warner Losh <imp@bsdimp.com> To: Peter Jeremy <peter@rulingia.com> Cc: YongHyeon PYUN <pyunyh@gmail.com>, freebsd-current@freebsd.org Subject: Re: dhclient cause up/down cycle after 239356 ? Message-ID: <B918DF2C-2606-496C-B8F6-614E43A279EA@bsdimp.com> In-Reply-To: <20120823013534.GA31015@server.rulingia.com> References: <20120821095527.GA33206@hell.ukr.net> <20120822171253.GB3300@michelle.cdnetworks.com> <20120822172822.GA52909@hell.ukr.net> <201208221535.01598.jhb@freebsd.org> <20120823013534.GA31015@server.rulingia.com>
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On Aug 22, 2012, at 7:35 PM, Peter Jeremy wrote: > On 2012-Aug-22 15:35:01 -0400, John Baldwin <jhb@freebsd.org> wrote: >> Hmm. Perhaps we could use a debouncer to ignore "short" link flaps? Kind of >> gross (and OpenBSD doesn't do this). For now this change basically ignores >> link up events if they occur with 5 seconds of the link down event. The 5 is >> hardcoded which is kind of yuck. > > I'm also a bit concerned about this for similar reasons to adrian@. > We need to distinguish between short link outages caused by (eg) a > switch admin reconfiguring the switch (which needs the lease to be > re-checked) and those caused by broken NICs which report link status > changes when they are touched. Maybe an alternative is to just ignore > link flaps when they occur within a few seconds of a script_go(). > (And/or make the ignore timeout configurable). > > Apart from fxp(4), does anyone know how many NICs are similarly > broken? > > Does anyone know why this issue doesn't bite OpenBSD? Does it have > a work-around to avoid resetting the link, not report link status > changes or just no-one has noticed the issue? Speaking of fxp(4), can't it defer reporting link status changes during the reset sequence it must perform? Wouldn't it be better to fix the broken driver(s) to behave better than to add a twisty maze of hacks to dhclient? Warnerhelp
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