fix(srv6): replace DSR delivery route in place to avoid a blackhole window#29
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…indow updateDeliveryRoute did RouteDel(old) then RouteAdd(new) on every local-backend membership change, leaving a window with no /128 delivery route where VIP traffic blackholed. RouteAdd is a non-multipath add, which VPP applies as an atomic replace of the prefix's paths, so a single RouteAdd(new) swaps the paths with no gap. RouteDel is kept only for the no-backends case (route removal). On add failure the old route is still installed, so state is retained and retried next reconcile.
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What
updateDeliveryRoutedidRouteDel(old)thenRouteAdd(new)on every local-backend membership change, leaving a window with no/128delivery route where VIP traffic blackholed.Fix
RouteAddis a non-multipath add, which VPP applies as an atomic replace of the prefix's paths. Skip the priorRouteDeland justRouteAdd(new)— no gap.RouteDelis kept only for the no-backends (removal) case; on add failure the old route is still installed and retried next reconcile.Review finding
Low (correctness) L6.
Test
GOOS=linux go vet ./calico-vpp-agent/cni/...green.