appc,ipn/ipnlocal: receive AppConnector updates via the event bus (#17411)

Add subscribers for AppConnector events

Make the RouteAdvertiser interface optional We cannot yet remove it because
the tests still depend on it to verify correctness. We will need to separately
update the test fixtures to remove that dependency.

Publish RouteInfo via the event bus, so we do not need a callback to do that. 
Replace it with a flag that indicates whether to treat the route info the connector 
has as "definitive" for filtering purposes.

Update the tests to simplify the construction of AppConnector values now that a
store callback is no longer required. Also fix a couple of pre-existing racy tests that 
were hidden by not being concurrent in the same way production is.

Updates #15160
Updates #17192

Change-Id: Id39525c0f02184e88feaf0d8a3c05504850e47ee
Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>

appc/appconnector_test.go

@@ -26,24 +26,15 @@ import (
 	"tailscale.com/util/slicesx"
 )
 
-func fakeStoreRoutes(*appctype.RouteInfo) error { return nil }
-
 func TestUpdateDomains(t *testing.T) {
 	ctx := t.Context()
 	bus := eventbustest.NewBus(t)
 	for _, shouldStore := range []bool{false, true} {
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: &appctest.RouteCollector{},
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: &appctest.RouteCollector{}})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		a.UpdateDomains([]string{"example.com"})
@@ -76,18 +67,12 @@ func TestUpdateRoutes(t *testing.T) {
 	for _, shouldStore := range []bool{false, true} {
 		w := eventbustest.NewWatcher(t, bus)
 		rc := &appctest.RouteCollector{}
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		a.updateDomains([]string{"*.example.com"})
@@ -149,18 +134,12 @@ func TestUpdateRoutesUnadvertisesContainedRoutes(t *testing.T) {
 	for _, shouldStore := range []bool{false, true} {
 		w := eventbustest.NewWatcher(t, bus)
 		rc := &appctest.RouteCollector{}
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		mak.Set(&a.domains, "example.com", []netip.Addr{netip.MustParseAddr("192.0.2.1")})
@@ -190,18 +169,12 @@ func TestDomainRoutes(t *testing.T) {
 	for _, shouldStore := range []bool{false, true} {
 		w := eventbustest.NewWatcher(t, bus)
 		rc := &appctest.RouteCollector{}
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 		a.updateDomains([]string{"example.com"})
 		if err := a.ObserveDNSResponse(dnsResponse("example.com.", "192.0.0.8")); err != nil {
@@ -232,18 +205,12 @@ func TestObserveDNSResponse(t *testing.T) {
 	for _, shouldStore := range []bool{false, true} {
 		w := eventbustest.NewWatcher(t, bus)
 		rc := &appctest.RouteCollector{}
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		// a has no domains configured, so it should not advertise any routes
@@ -346,18 +313,12 @@ func TestWildcardDomains(t *testing.T) {
 	for _, shouldStore := range []bool{false, true} {
 		w := eventbustest.NewWatcher(t, bus)
 		rc := &appctest.RouteCollector{}
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		a.updateDomains([]string{"*.example.com"})
@@ -522,18 +483,12 @@ func TestUpdateRouteRouteRemoval(t *testing.T) {
 			}
 		}
 
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		// nothing has yet been advertised
@@ -584,18 +539,12 @@ func TestUpdateDomainRouteRemoval(t *testing.T) {
 			}
 		}
 
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		assertRoutes("appc init", []netip.Prefix{}, []netip.Prefix{})
@@ -665,18 +614,12 @@ func TestUpdateWildcardRouteRemoval(t *testing.T) {
 			}
 		}
 
-		var a *AppConnector
-		if shouldStore {
-			a = NewAppConnector(Config{
-				Logf:            t.Logf,
-				EventBus:        bus,
-				RouteAdvertiser: rc,
-				RouteInfo:       &appctype.RouteInfo{},
-				StoreRoutesFunc: fakeStoreRoutes,
-			})
-		} else {
-			a = NewAppConnector(Config{Logf: t.Logf, EventBus: bus, RouteAdvertiser: rc})
-		}
+		a := NewAppConnector(Config{
+			Logf:            t.Logf,
+			EventBus:        bus,
+			RouteAdvertiser: rc,
+			HasStoredRoutes: shouldStore,
+		})
 		t.Cleanup(a.Close)
 
 		assertRoutes("appc init", []netip.Prefix{}, []netip.Prefix{})
@@ -842,8 +785,7 @@ func TestUpdateRoutesDeadlock(t *testing.T) {
 		Logf:            t.Logf,
 		EventBus:        bus,
 		RouteAdvertiser: rc,
-		RouteInfo:       &appctype.RouteInfo{},
-		StoreRoutesFunc: fakeStoreRoutes,
+		HasStoredRoutes: true,
 	})
 	t.Cleanup(a.Close)