Re: [PATCH 1/2] IPV4: remove addresses and routes when carrier is lost

[Patrick McHardy <kaber@trash.net>]

Stephen Hemminger wrote:
> On Tue, 03 Jun 2008 18:03:46 +0200
> Patrick McHardy <kaber@trash.net> wrote:
> 
>> Stephen Hemminger wrote:
>>> On Tue, 3 Jun 2008 11:05:24 -0400
>>> lsorense@csclub.uwaterloo.ca (Lennart Sorensen) wrote:
>>>
>>>> On Mon, Jun 02, 2008 at 04:52:49PM -0700, Stephen Hemminger wrote:
>>>>> This patch adds a new configuration sysctl that causes link loss to clear
>>>>> FIB state in the same way as admin down. This allows for routing daemons
>>>>> like Quagga which have option to remove routes when carrier is lost.
>>>>>
>>>>> This has been a long standing problem with Quagga on Linux with complaints
>>>>> on the developers list going back to 2004. Fixing it properly, so the routing 
>>>>> daemon manages the RIB, and the kernel manages the FIB, requires changes to
>>>>> both parts.
>>>> Does this cover only the local route for the interface, or all routes
>>>> assigned staticly to the interface too?
>>> The patch makes carrier down == interface down. So the same
>>> behaviour as doing 'ip link set dev eth3 down'
>>
>> Can't the routing daemon simply ignore routes with a
>> device that has no carrier?
>>
> 
> It does that, but the problem is that packets get routed in kernel
> to interfaces without carrier, rather than being correctly rerouted
> over alternate paths.

I see, thanks for the explanation.