[PATCH 2/4] Helper functions for uplink dev and gateway

[Gernot Hillier]

Am 17.10.2017 um 10:07 schrieb David Woodhouse:
> On Wed, 2017-10-11 at 22:40 +0200, Gernot Hillier wrote:
>>
>> +       get_uplink_gw() {
>> +               # If we have a specific route to VPNGATEWAY, then this is our
>> +               # Internet uplink (VPN tunnel active). If tunnel is not active,
>> +               # then the default route should be our uplink.
>> +               uplink_route=`netstat -r -n | grep "^$VPNGATEWAY"`
>> +               if [ -n "$uplink_route" ]; then
>> +                       echo "$uplink_route" | awk '{ print $2; }'
>> +               else
>> +                       get_default_gw
>> +               fi
> 
> That isn't strictly true. I've certainly seen reports from German
> universities where they have some weird wifi setup with a VPN server on
> the *local* network, not accessible via the default route. I thought we
> fixed that... but maybe we did so only for the iproute2 case, where 'ip
> route get' works more sanely?

Well, now it gets weird.

We need this for setting up split-exclude routes which are intended to
tell your client to connect to a limited number of targets directly, not
over the VPN tunnel (in our case, they want to force people to be
connected to company's Intranet completely, but use the exclude-rules
for time-critical stuff like WebRTC).

So, for the case you describe my code should probably do the right thing
as the targets for split-exclude rules are likely not in your local
university network. Probably.

But, generally spoken, the helper function might get things wrong. Hmmmm.

--
Gernot