conf: Don't exit if sourced default route has no gateway

If we use a template interface without a gateway on the default
route, we can still offer almost complete functionality, except that,
of course, we can't map the gateway address to the outer namespace or
host, and that we have no obvious server address or identifier for
use in DHCP's siaddr and option 54 (Server identifier, mandatory).

Continue, if we have a default route but no default gateway, and
imply --no-map-gw and --no-dhcp in that case. NDP responder and
DHCPv6 should be able to work as usual because we require a
link-local address to be present, and we'll fall back to that.

Together with the previous commits implementing an actual copy of
routes from the outer namespace, this should finally fix the
operation of 'pasta --config-net' for cases where we have a default
route on the host, but no default gateway, as it's the case for
tap-style routes, including typical Wireguard endpoints.

Reported-by: me@yawnt.com
Link: https://bugs.passt.top/show_bug.cgi?id=49
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

0 files changed, 0 insertions, 0 deletions