[systemd-devel] [PATCH] network: dhcp: create explicit host route to gateway

[Tom Gundersen]

On Thu, Mar 20, 2014 at 7:53 PM, Brandon Philips <brandon at ifup.co> wrote:
> This is a better approach that was suggested by Mike and ack'd by Tom.
>
> Some DHCP servers gives you a netmask of 255.255.255.255 so the gateway is not
> routable. Other DHCP client implementations look through the existing routes to
> figure out if they should add an explicit host route. See below for a link.
>
> However, it makes sense to just create the route explicitly whether it is
> needed or not since it is explicit, makes the dhcp route entries independent of
> other entries and saves us from knowing the state of the kernel tables.
>
> After patch route table on a machine with a network (common case):
>
> default via 10.0.2.2 dev ens3
> 10.0.2.0/24 dev ens3  proto kernel  scope link  src 10.0.2.15
> 10.0.2.2 dev ens3  scope link
>
> After patch route table on a machine without a network (this case):
>
> default via 10.240.0.1 dev ens4v1
> 10.240.0.1 dev ens4v1  scope link
>
> The code from dhcpcd that works around this issue is on line 637.
> https://android.googlesource.com/platform/external/dhcpcd/+/master/configure.c

Applied. Thanks a lot for doing this work!

Cheers,

Tom