svn commit: r274966 - head/sys/net

[John-Mark Gurney]

Philip Paeps wrote this message on Mon, Nov 24, 2014 at 21:18 +0100:
> On 2014-11-24 22:40:22 (+0300), Gleb Smirnoff <glebius at FreeBSD.org> 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,

Can you update the description of the sysctl?  That way when we want
to remove it, we can...  Any sysctl that makes a release is an API that
we need to provide compatibility for... :(

-- 
  John-Mark Gurney				Voice: +1 415 225 5579

     "All that I will do, has been done, All that I have, has not."