svn commit: r274966 - head/sys/net

[Gleb Smirnoff]

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-*@?

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).

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.

-- 
Totus tuus, Glebius.