Date: Tue, 25 Jul 2006 10:39:24 -0700 From: John-Mark Gurney <gurney_j@resnet.uoregon.edu> To: Fredrik Lindberg <fli+freebsd-current@shapeshifter.se> Cc: freebsd-current@freebsd.org Subject: Re: Extending EVFILT_NETDEV to support ip-address changes Message-ID: <20060725173924.GR96589@funkthat.com> In-Reply-To: <44C61470.3070005@shapeshifter.se> References: <44C61470.3070005@shapeshifter.se>
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Fredrik Lindberg wrote this message on Tue, Jul 25, 2006 at 14:54 +0200:
> I have a suggestion to add support for ip-address changes to the
> kqueue (EVFILT_NETDEV) system.
> The infrastructure for EVFILT_NETDEV is already in place and this
> only introduce NOTE_NEWADDR and NOTE_DELADDR and minor modifications
> to the interface ioctl handler.
>
> The purpose is not to replicate the functionality of the
> routing socket, but to provide a low overhead mechanism for
> monitoring a given interface for address changes.
> No information about the event is sent through the kqueue system,
> instead it will be up to the caller to query the system (if wanted)
> to obtain information about the current state of the interface
> that is being monitored.
>
> I have attached a suggested patch, any thoughts?
Looks basicly good, though you will need to rethink how the filt_netdev
handles the hint.. since right now it just sets kn_data to whatever
hint is.. This is fine when it was simply one of NOTE_LINK{UP,DOWN,INV},
but now that you have an extra flag, the NOTE_DELADDR could make an
app miss the LINK status if it was looking at data instead of fflags..
Plus, are you sure everyone that is using NOTE_LINK* are treating them
as a bit mask? maybe we need to redefine NOTE_LINK* as a mask plus set
of values, since each of the NOTE_LINK* can only be set once... but
the NOTE_ADDR{NEW,DEL} should probably be flags...
We may want to reverse the naming to NOTE_ADDR{NEW,DEL} so that we have
the more generic first before the more specific... similar to NOTE_LINK*...
Suffice it to say, this cannot be back ported to RELENG_6 due to API
breakage...
--
John-Mark Gurney Voice: +1 415 225 5579
"All that I will do, has been done, All that I have, has not."
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