ipn/ipnlocal: Update hostinfo to control on service config change

This commit fixes the bug that c2n requests are skiped when updating vipServices in serveConfig. This then resulted
netmap update being skipped which caused inaccuracy of Capmap info on client side. After this fix, client always
inform control about it's vipServices config changes.

Fixes tailscale/corp#29219

Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com>

ipn/ipnlocal/local.go

@@ -6146,17 +6146,17 @@ func (b *LocalBackend) setTCPPortsInterceptedFromNetmapAndPrefsLocked(prefs ipn.
 		}
 	}
 
-	// Update funnel info in hostinfo and kick off control update if needed.
+	// Update funnel and service hash info in hostinfo and kick off control update if needed.
-	b.updateIngressLocked()
+	b.updateIngressAndServiceHashLocked(prefs)
 	b.setTCPPortsIntercepted(handlePorts)
 	b.setVIPServicesTCPPortsInterceptedLocked(vipServicesPorts)
 }
 
-// updateIngressLocked updates the hostinfo.WireIngress and hostinfo.IngressEnabled fields and kicks off a Hostinfo
+// updateIngressAndServiceHashLocked updates the hostinfo.ServicesHash, hostinfo.WireIngress and
-// update if the values have changed.
+// hostinfo.IngressEnabled fields and kicks off a Hostinfo update if the values have changed.
 //
 // b.mu must be held.
-func (b *LocalBackend) updateIngressLocked() {
+func (b *LocalBackend) updateIngressAndServiceHashLocked(prefs ipn.PrefsView) {
 	if b.hostinfo == nil {
 		return
 	}
@@ -6171,6 +6171,12 @@ func (b *LocalBackend) updateIngressLocked() {
 		b.hostinfo.WireIngress = wire
 		hostInfoChanged = true
 	}
+	latestHash := b.vipServiceHash(b.vipServicesFromPrefsLocked(prefs))
+	if b.hostinfo.ServicesHash != latestHash {
+		b.logf("Hostinfo.ServicesHash changed to %s", latestHash)
+		b.hostinfo.ServicesHash = latestHash
+		hostInfoChanged = true
+	}
 	// Kick off a Hostinfo update to control if ingress status has changed.
 	if hostInfoChanged {
 		b.goTracker.Go(b.doSetHostinfoFilterServices)

ipn/ipnlocal/local_test.go

@@ -5134,7 +5134,8 @@ func TestUpdatePrefsOnSysPolicyChange(t *testing.T) {
 	}
 }
 
-func TestUpdateIngressLocked(t *testing.T) {
+func TestUpdateIngressAndServiceHashLocked(t *testing.T) {
+	prefs := ipn.NewPrefs().View()
 	tests := []struct {
 		name              string
 		hi                *tailcfg.Hostinfo
@@ -5163,6 +5164,16 @@ func TestUpdateIngressLocked(t *testing.T) {
 			wantWireIngress:   false, // implied by wantIngress
 			wantControlUpdate: true,
 		},
+		{
+			name: "empty_hostinfo_service_configured",
+			hi:   &tailcfg.Hostinfo{},
+			sc: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
+			wantControlUpdate: true,
+		},
 		{
 			name: "empty_hostinfo_funnel_disabled",
 			hi:   &tailcfg.Hostinfo{},
@@ -5175,7 +5186,7 @@ func TestUpdateIngressLocked(t *testing.T) {
 			wantControlUpdate: true,
 		},
 		{
-			name: "empty_hostinfo_no_funnel",
+			name: "empty_hostinfo_no_funnel_no_service",
 			hi:   &tailcfg.Hostinfo{},
 			sc: &ipn.ServeConfig{
 				TCP: map[uint16]*ipn.TCPPortHandler{
@@ -5196,6 +5207,17 @@ func TestUpdateIngressLocked(t *testing.T) {
 			wantIngress:     true,
 			wantWireIngress: false, // implied by wantIngress
 		},
+		{
+			name: "service_hash_no_change",
+			hi: &tailcfg.Hostinfo{
+				ServicesHash: "5c5fd5093eb8764e1b70110dbfe5bc4370a214fdc5bc5a0fcdf32689fb5cb571",
+			},
+			sc: &ipn.ServeConfig{
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
+		},
 		{
 			name: "funnel_disabled_no_change",
 			hi: &tailcfg.Hostinfo{
@@ -5208,6 +5230,14 @@ func TestUpdateIngressLocked(t *testing.T) {
 			},
 			wantWireIngress: true, // true if there is any AllowFunnel block
 		},
+		{
+			name: "service_got_removed",
+			hi: &tailcfg.Hostinfo{
+				ServicesHash: "5c5fd5093eb8764e1b70110dbfe5bc4370a214fdc5bc5a0fcdf32689fb5cb571",
+			},
+			sc:                &ipn.ServeConfig{},
+			wantControlUpdate: true,
+		},
 		{
 			name: "funnel_changes_to_disabled",
 			hi: &tailcfg.Hostinfo{
@@ -5235,6 +5265,22 @@ func TestUpdateIngressLocked(t *testing.T) {
 			wantWireIngress:   false, // implied by wantIngress
 			wantControlUpdate: true,
 		},
+		{
+			name: "both_funnel_and_service_changes",
+			hi: &tailcfg.Hostinfo{
+				IngressEnabled: true,
+			},
+			sc: &ipn.ServeConfig{
+				AllowFunnel: map[ipn.HostPort]bool{
+					"tailnet.xyz:443": false,
+				},
+				Services: map[tailcfg.ServiceName]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
+			wantWireIngress:   true, // true if there is any AllowFunnel block
+			wantControlUpdate: true,
+		},
 	}
 
 	for _, tt := range tests {
@@ -5256,7 +5302,7 @@ func TestUpdateIngressLocked(t *testing.T) {
 			})()
 
 			was := b.goTracker.StartedGoroutines()
-			b.updateIngressLocked()
+			b.updateIngressAndServiceHashLocked(prefs)
 
 			if tt.hi != nil {
 				if tt.hi.IngressEnabled != tt.wantIngress {
@@ -5265,6 +5311,10 @@ func TestUpdateIngressLocked(t *testing.T) {
 				if tt.hi.WireIngress != tt.wantWireIngress {
 					t.Errorf("WireIngress = %v, want %v", tt.hi.WireIngress, tt.wantWireIngress)
 				}
+				svcHash := b.vipServiceHash(b.vipServicesFromPrefsLocked(prefs))
+				if tt.hi.ServicesHash != svcHash {
+					t.Errorf("ServicesHash = %v, want %v", tt.hi.ServicesHash, svcHash)
+				}
 			}
 
 			startedGoroutine := b.goTracker.StartedGoroutines() != was