Support reapply of
I did these patches are part of a branch to add policy routing for WireGuard. That branch is still WIP, but propose these patches early on.
There is also patches to add and use
nm_platform_sysctl_ip_conf_get_rp_filter_ipv4(). I did these two patches because I thought I would need
nm_platform_sysctl_ip_conf_get_rp_filter_ipv4() somewhere else (on the WireGuard branch). Regardless of that, it seems better than without, hence I propose it.