If a route is shadowed by another route to the same network it's a good indication we're multihoming and want to disable the Strict RP filtering.
75faf5b route-manager: add routine to query route shadowing for a link
src/nm-route-manager.c | 27 +++++++++++++++++++++++++++
src/nm-route-manager.h | 1 +
2 files changed, 28 insertions(+)