Updates #5162 Change-Id: Id7bdec303b25471f69d542f8ce43805328d56c12 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
Combine the code between `LocalBackend.CheckIPForwarding` and `controlclient.ipForwardingBroken`. Fixes #4300 Signed-off-by: Maisem Ali <maisem@tailscale.com>