Re: [PATCH] network: don't die if gateway is down and root server is local

[Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 10/15/2010 02:05 PM, P치draig Brady wrote:
> On 08/10/10 16:19, P치draig Brady wrote:
>> On 08/10/10 15:17, Seewer Philippe wrote:
>>> On 10/08/2010 03:59 PM, P치draig Brady wrote:
>>
>>>> Is it right to die if we can't contact the router?
>>> Usually yes. Either because the rootserver is behind the router or if
>>> you supplied routing information it's safe to assume that later you want
>>> it to work anyway.
>>
>> Well in my case the router is just needed for browsing the net.
>> All other services are provided locally.
>>
>>> But yes, usually. I would have preferred to somehow a subnet check on
>>> the rootserver to decide what or if to check. But alas, not all netroot
>>> variants know the ip of their rootserver at that point.
>>
>> Right, but no need to penalize the common case.
>> I.E. we can bypass all this if the rootserver is known,
>> and on the same subnet.
>
> This seems to work.
>
> cheers,
> P치draig.
>
>  From a1a1fac1a1cfc8bd22417923823f3d64c29dd44f Mon Sep 17 00:00:00 2001
> From: =?utf-8?q?P=C3=A1draig=20Brady?=<P@draigBrady.com>
> Date: Fri, 15 Oct 2010 12:58:31 +0100
> Subject: [PATCH] network: make gateway optional with a local root server
>
> * modules.d/40network/netroot: Don't arping the gateway
> if we don't need to
> ---
>   modules.d/40network/netroot |   25 ++++++++++++++++++-------
>   1 files changed, 18 insertions(+), 7 deletions(-)
>
> diff --git a/modules.d/40network/netroot b/modules.d/40network/netroot
> index 81a9ad3..12717b1 100755
> --- a/modules.d/40network/netroot
> +++ b/modules.d/40network/netroot
> @@ -83,22 +83,33 @@ done
>   [ -e /tmp/net.$netif.override ]&&  . /tmp/net.$netif.override
>   [ -e /tmp/dhclient.$netif.dhcpopts ]&&  . /tmp/dhclient.$netif.dhcpopts
>
> -# Handle STP Timeout: arping default router or if not available the
> -# root server. Note: This assumes that if no router is present the
> +# Handle STP Timeout: arping the default router if root server is
> +# unknown or not local, or if not available the root server.
> +# Note: This assumes that if no router is present the
>   # root server is on the same subnet.
>   #
>   # TODO There's some netroot variants that don't (yet) have their
>   # server-ip netroot
> -[ -n "$new_routers" ]&&  dest=${new_routers%%,*}
> -[ -n "$gw" ]&&  dest=$gw
> -if [ -z "$dest" ] ; then
> +[ "$new_routers" ]&&  gw_ip=${new_routers%%,*}
> +[ "$gw" ]&&  gw_ip=$gw
> +if [ "$netroot" ]; then
>       dummy=${netroot#*:}
>       dummy=${dummy%%:*}
>       case "$dummy" in
> -        [0-9]*\.[0-9]*\.[0-9]*\.[0-9]*) dest=$dummy;;
> +        [0-9]*\.[0-9]*\.[0-9]*\.[0-9]*) netroot_ip=$dummy;;
>       esac
>   fi
> -if [ -n "$dest" ]&&  ! arping -q -f -w 60 -I $netif $dest ; then
> +dest="$gw_ip"
> +if [ "$netroot_ip" ]; then
> +    if [ -z "$dest" ]; then
> +         # no gateway so check root server
> +        dest="$netroot_ip"
> +    elif ! ip route get "$netroot_ip" | grep -qF ' via '; then
> +        # local root server, so don't arping gateway
> +        dest="$netroot_ip"
> +    fi
> +fi
> +if [ "$dest" ]&&  ! arping -q -f -w 60 -I $netif $dest; then
>       die "Resolving $dest via ARP on $netif failed"
>   fi
>

please use [ -n "$var" ]