Function TestRouter_BackupRouteOverridesHeldRoute

core/router_test.go:645–697

(t *testing.T)

}

func TestRouter_BackupRouteOverridesHeldRoute(t *testing.T) {
	tunables := ConfigureConstants()
	// Topology:
	// A --(1)-- C
	// A --(1)-- B --(10)-- C
	// Initially A prefers A-C path.
	// When A-C fails, A should be starved, request a seqno, and then switch to A-B-C.

	h := &RouterHarness{}
	cPrefix := nodeToPrefix("C")
	rs := &state.RouterState{
		RouterTunables: tunables,
		Id:             "A",
		SelfSeqno:      make(map[netip.Prefix]uint16),
		Routes:         make(map[netip.Prefix]state.SelRoute),
		Sources:        make(map[state.Source]state.FD),
		Neighbours:     MakeNeighbours("B", "C"),
		Advertised:     map[netip.Prefix]state.Advertisement{nodeToPrefix("A"): {NodeId: state.NodeId("A"), Expiry: maxTime}},
	}

	AC := AddLink(rs, NewMockEndpoint("C", 1))
	_ = AddLink(rs, NewMockEndpoint("B", 1))

	// C's advertisement via direct link
	h.NeighUpdate(rs, "C", "C", cPrefix, 0, 0)
	// B's advertisement of C (cost 10). This is initially UNFEASIBLE because 10 > 1 (current FD).
	h.NeighUpdate(rs, "B", "C", cPrefix, 0, 10)

	ComputeRoutes(rs, h)

	// Initially A prefers C via direct link
	assert.Equal(t, "C", string(rs.Routes[cPrefix].Nh))
	assert.Equal(t, uint32(1), rs.Routes[cPrefix].Metric)

	// Now AC link goes down
	RemoveLink(rs, AC)
	ComputeRoutes(rs, h)

	// A-C route should be retracted and held as INF
	assert.Equal(t, state.INF, rs.Routes[cPrefix].Metric)

	// A should realize it's starved and request a higher seqno
	SolveStarvation(rs, h)
	h.GetActions().AssertContains(t, BroadcastRequestSeqno(state.Source{NodeId: "C", Prefix: cPrefix}, uint16(1), uint8(64)))

	// Now B advertises C with the higher seqno (1). This is now FEASIBLE.
	h.NeighUpdate(rs, "B", "C", cPrefix, 1, 10)
	ComputeRoutes(rs, h)

	// A should now successfully switch to B
	assert.Equal(t, "B", string(rs.Routes[cPrefix].Nh))
	assert.Equal(t, uint32(11), rs.Routes[cPrefix].Metric)
}

func TestRouter_RetractedByClearedWhenHeldRouteRecovers(t *testing.T) {
	tunables := ConfigureConstants()