From owner-svn-src-all@FreeBSD.ORG Mon Nov 24 20:18:30 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 5779D567; Mon, 24 Nov 2014 20:18:30 +0000 (UTC) Received: from rincewind.trouble.is (rincewind.trouble.is [88.198.44.60]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 12D2BBF4; Mon, 24 Nov 2014 20:18:29 +0000 (UTC) Received: by rincewind.trouble.is (Postfix, from userid 1001) id 7FC0C749; Mon, 24 Nov 2014 21:18:21 +0100 (CET) Date: Mon, 24 Nov 2014 21:18:21 +0100 From: Philip Paeps To: Gleb Smirnoff Subject: Re: svn commit: r274966 - head/sys/net Message-ID: <20141124201821.GY95784@rincewind.trouble.is> Mail-Followup-To: Gleb Smirnoff , src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org References: <201411241400.sAOE0Srq063100@svn.freebsd.org> <20141124194022.GR47144@FreeBSD.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20141124194022.GR47144@FreeBSD.org> X-PGP-Fingerprint: 73C5 0671 B4B6 7E19 1BAD F87A BB5E 2C46 2A0F A8B0 X-Date: Today is Pungenday, the 36th day of The Aftermath in the YOLD 3180 X-Phase-of-Moon: The Moon is Waxing Crescent (7% of Full) X-Philip-Conspiracy: There is no conspiracy X-Checked-By-NSA: Probably User-Agent: Mutt/1.5.23 (2014-03-12) Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 Nov 2014 20:18:30 -0000 On 2014-11-24 22:40:22 (+0300), Gleb Smirnoff wrote: > On Mon, Nov 24, 2014 at 02:00:28PM +0000, Philip Paeps wrote: > P> Author: philip > P> Date: Mon Nov 24 14:00:27 2014 > P> New Revision: 274966 > P> URL: https://svnweb.freebsd.org/changeset/base/274966 > P> > P> Log: > P> Add a sysctl `net.link.tap.deladdrs_on_close' to configure whether tap > P> should delete configured addresses and routes when the interface is > P> closed. Default is enabled (preserve current behaviour). > P> > P> MFC after: 1 week > > Any time I see yet another sysctl knob added I ask myself: what if I want > this feature on tap0 but doesn't want it on tap1? What if want it on host, > but doesn't want it on vmnet-enabled jail? Where from could I learn about > this sysctl if I am not subscribed to svn-src-*@? I admit that this one was a hack written in anger a while back. When I hacked this, I was struggling with a bunch of bhyve instances with fiddly point to point routes and every time I restarted a bhyve, I'd have to fix my routing table again. That got frustrating quickly. Not an excuse. Just an explanation. > Of course adding a sysctl knob is faster and easier for a FreeBSD hacker. > But is it a better for a FreeBSD user? Are we making OS for just ourselves? > > Look, we've got tapifioctl(). If you are too lazy to introduce new > ioctl command and code it support in ifconfig, in this case you can just > use any of IFF_LINK0, IFF_LINK1, IFF_LINK2 flag to toggle this feature > via SIOCSIFFLAGS. And then document it in tap(4). Note that I semi-purposely didn't document this in tap(4). I should have pointed that out in the commit message, sorry. When I wrote this, this summer, I meant to ask about the magical and very legacy-looking VMware vmnet hacks in the driver. Are those still relevant? Is there still a VMWare port that relies on this? What about the comment that legacy devfs cloning interferes with ssh(1) (added seven years ago), is that still true? > Finally, if later some developer comes and does it in a proper way, then > he would have a burden of supporting your sysctl for backwards compatibility, > because you very quickly MFCed it. > > P.S. I am sorry if my email sounds like old man's grumbling. No problem. I'm happy to fix this 'better'. Old men often grumble sense (I keep telling myself as I get older...). Philip -- Philip Paeps Senior Reality Engineer Ministry of Information