Re: Retiring dhclient

[Joerg Sonnenberger <joerg%britannica.bec.de@localhost>]

On Tue, Nov 15, 2011 at 10:26:28AM -0600, David Young wrote:
> On Tue, Nov 15, 2011 at 05:10:04PM +0100, Joerg Sonnenberger wrote:
> > Hi all,
> > I would like to retire dhclient before netbsd-6. I don't think it
> > provides a functional advantage over dhcpcd. The reverse is not true.
> > I want to collect TODO items for this to happen, mostly in the
> > documentation section to deal with the changes.
> > 
> *snip snip*
> > The second important item is that dhcpcd by default depends on working
> > link state management in the driver. Sadly, quite a few of our older
> > drivers don't do it properly. Typical issue is calling if_reset from
> > if_ioctl e.g. to update multicast filters. This is a two fold issue:
> > (1) Fixing kernel drivers to not do this.
> > (2) Documenting the work arounds (aka crippling dhcpcd with -K)
> > Building a list of drivers affected would be a good start.
> 
> I do not recognize the typical based on your description.  Please
> explain in more detail.

Consider a driver using mii(4). Calling reset from if_ioctl normally
does a reset of the PHY. This in turn results in a link down message to
userland, so dhcpcd will renegociate the lease. Typical circumstances
for calling reset are changes to the multicast filter and
entering/leaving promisc mode. For some PHYs it might really be
necessary to tell the generic layer to ignore link state changes for a
bit, but the common use cases shouldn't require anything like that.

> 
> > What other items are missing?
> 
> dhclient-exit-hooks compatibility.

Can you be more specific? The variables are essentially the same,
equivalent functionality is available (see the section in my original
mail that you've skipped).

Joerg