ipn/ipnlocal: connect serve config to c2n endpoint

This commit updates the VIPService c2n endpoint on client to response with actual VIPService configuration stored
in the serve config.

Fixes tailscale/corp#24510
Signed-off-by: KevinLiang10 <37811973+KevinLiang10@users.noreply.github.com>

ipn/ipnlocal/local.go

@@ -11,6 +11,7 @@ import (
 	"context"
 	"crypto/sha256"
 	"encoding/base64"
+	"encoding/hex"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -5017,13 +5018,7 @@ func (b *LocalBackend) applyPrefsToHostinfoLocked(hi *tailcfg.Hostinfo, prefs ip
 	}
 	hi.SSH_HostKeys = sshHostKeys
 
-	services := vipServicesFromPrefs(prefs)
-	if len(services) > 0 {
-		buf, _ := json.Marshal(services)
-		hi.ServicesHash = fmt.Sprintf("%02x", sha256.Sum256(buf))
-	} else {
-		hi.ServicesHash = ""
-	}
+	hi.ServicesHash = b.vipServiceHashLocked(prefs)
 
 	// The Hostinfo.WantIngress field tells control whether this node wants to
 	// be wired up for ingress connections. If harmless if it's accidentally
@@ -7659,28 +7654,38 @@ func maybeUsernameOf(actor ipnauth.Actor) string {
 func (b *LocalBackend) VIPServices() []*tailcfg.VIPService {
 	b.mu.Lock()
 	defer b.mu.Unlock()
-	return vipServicesFromPrefs(b.pm.CurrentPrefs())
+	return b.vipServicesFromPrefsLocked(b.pm.CurrentPrefs())
 }
 
-func vipServicesFromPrefs(prefs ipn.PrefsView) []*tailcfg.VIPService {
+func (b *LocalBackend) vipServiceHashLocked(prefs ipn.PrefsView) string {
+	services := b.vipServicesFromPrefsLocked(prefs)
+	if len(services) == 0 {
+		return ""
+	}
+	buf, err := json.Marshal(services)
+	if err != nil {
+		b.logf("vipServiceHashLocked: %v", err)
+		return ""
+	}
+	hash := sha256.Sum256(buf)
+	return hex.EncodeToString(hash[:])
+}
+
+func (b *LocalBackend) vipServicesFromPrefsLocked(prefs ipn.PrefsView) []*tailcfg.VIPService {
 	// keyed by service name
 	var services map[string]*tailcfg.VIPService
-
-	// TODO(naman): this envknob will be replaced with service-specific port
-	// information once we start storing that.
-	var allPortsServices []string
-	if env := envknob.String("TS_DEBUG_ALLPORTS_SERVICES"); env != "" {
-		allPortsServices = strings.Split(env, ",")
+	if !b.serveConfig.Valid() {
+		return nil
 	}
 
-	for _, s := range allPortsServices {
-		mak.Set(&services, s, &tailcfg.VIPService{
-			Name:  s,
-			Ports: []tailcfg.ProtoPortRange{{Ports: tailcfg.PortRangeAny}},
+	for svc, config := range b.serveConfig.Services().All() {
+		mak.Set(&services, svc, &tailcfg.VIPService{
+			Name:  svc,
+			Ports: config.ServicePortRange(),
 		})
 	}
 
-	for _, s := range prefs.AdvertiseServices().AsSlice() {
+	for _, s := range prefs.AdvertiseServices().All() {
 		if services == nil || services[s] == nil {
 			mak.Set(&services, s, &tailcfg.VIPService{
 				Name: s,

ipn/ipnlocal/local_test.go

@@ -30,7 +30,6 @@ import (
 	"tailscale.com/control/controlclient"
 	"tailscale.com/drive"
 	"tailscale.com/drive/driveimpl"
-	"tailscale.com/envknob"
 	"tailscale.com/health"
 	"tailscale.com/hostinfo"
 	"tailscale.com/ipn"
@@ -4509,15 +4508,15 @@ func TestConfigFileReload(t *testing.T) {
 
 func TestGetVIPServices(t *testing.T) {
 	tests := []struct {
-		name       string
-		advertised []string
-		mapped     []string
-		want       []*tailcfg.VIPService
+		name        string
+		advertised  []string
+		serveConfig *ipn.ServeConfig
+		want        []*tailcfg.VIPService
 	}{
 		{
 			"advertised-only",
 			[]string{"svc:abc", "svc:def"},
-			[]string{},
+			&ipn.ServeConfig{},
 			[]*tailcfg.VIPService{
 				{
 					Name:   "svc:abc",
@@ -4530,9 +4529,13 @@ func TestGetVIPServices(t *testing.T) {
 			},
 		},
 		{
-			"mapped-only",
+			"served-only",
 			[]string{},
-			[]string{"svc:abc"},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
 			[]*tailcfg.VIPService{
 				{
 					Name:  "svc:abc",
@@ -4541,9 +4544,13 @@ func TestGetVIPServices(t *testing.T) {
 			},
 		},
 		{
-			"mapped-and-advertised",
-			[]string{"svc:abc"},
+			"served-and-advertised",
 			[]string{"svc:abc"},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
 			[]*tailcfg.VIPService{
 				{
 					Name:   "svc:abc",
@@ -4553,9 +4560,13 @@ func TestGetVIPServices(t *testing.T) {
 			},
 		},
 		{
-			"mapped-and-advertised-separately",
+			"served-and-advertised-different-service",
 			[]string{"svc:def"},
-			[]string{"svc:abc"},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {Tun: true},
+				},
+			},
 			[]*tailcfg.VIPService{
 				{
 					Name:  "svc:abc",
@@ -4567,14 +4578,78 @@ func TestGetVIPServices(t *testing.T) {
 				},
 			},
 		},
+		{
+			"served-with-port-ranges-one-range-single",
+			[]string{},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {TCP: map[uint16]*ipn.TCPPortHandler{
+						80: {HTTPS: true},
+					}},
+				},
+			},
+			[]*tailcfg.VIPService{
+				{
+					Name:  "svc:abc",
+					Ports: []tailcfg.ProtoPortRange{{Proto: 6, Ports: tailcfg.PortRange{First: 80, Last: 80}}},
+				},
+			},
+		},
+		{
+			"served-with-port-ranges-one-range-multiple",
+			[]string{},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {TCP: map[uint16]*ipn.TCPPortHandler{
+						80: {HTTPS: true},
+						81: {HTTPS: true},
+						82: {HTTPS: true},
+					}},
+				},
+			},
+			[]*tailcfg.VIPService{
+				{
+					Name:  "svc:abc",
+					Ports: []tailcfg.ProtoPortRange{{Proto: 6, Ports: tailcfg.PortRange{First: 80, Last: 82}}},
+				},
+			},
+		},
+		{
+			"served-with-port-ranges-multiple-ranges",
+			[]string{},
+			&ipn.ServeConfig{
+				Services: map[string]*ipn.ServiceConfig{
+					"svc:abc": {TCP: map[uint16]*ipn.TCPPortHandler{
+						80:   {HTTPS: true},
+						81:   {HTTPS: true},
+						82:   {HTTPS: true},
+						1212: {HTTPS: true},
+						1213: {HTTPS: true},
+						1214: {HTTPS: true},
+					}},
+				},
+			},
+			[]*tailcfg.VIPService{
+				{
+					Name: "svc:abc",
+					Ports: []tailcfg.ProtoPortRange{
+						{Proto: 6, Ports: tailcfg.PortRange{First: 80, Last: 82}},
+						{Proto: 6, Ports: tailcfg.PortRange{First: 1212, Last: 1214}},
+					},
+				},
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			envknob.Setenv("TS_DEBUG_ALLPORTS_SERVICES", strings.Join(tt.mapped, ","))
+			lb := newLocalBackendWithTestControl(t, false, func(tb testing.TB, opts controlclient.Options) controlclient.Client {
+				return newClient(tb, opts)
+			})
+			lb.serveConfig = tt.serveConfig.View()
 			prefs := &ipn.Prefs{
 				AdvertiseServices: tt.advertised,
 			}
-			got := vipServicesFromPrefs(prefs.View())
+			got := lb.vipServicesFromPrefsLocked(prefs.View())
 			slices.SortFunc(got, func(a, b *tailcfg.VIPService) int {
 				return strings.Compare(a.Name, b.Name)
 			})

ipn/serve.go

@@ -16,7 +16,9 @@ import (
 
 	"tailscale.com/ipn/ipnstate"
 	"tailscale.com/tailcfg"
+	"tailscale.com/types/ipproto"
 	"tailscale.com/util/mak"
+	"tailscale.com/util/set"
 )
 
 // ServeConfigKey returns a StateKey that stores the
@@ -655,3 +657,41 @@ func (v ServeConfigView) HasFunnelForTarget(target HostPort) bool {
 	}
 	return false
 }
+
+// ServicePortRange returns the list of tailcfg.ProtoPortRange that represents
+// the proto/ports pairs that are being served by the service.
+//
+// Right now Tun mode is the only thing supports UDP, otherwise serve only supports TCP.
+func (v ServiceConfigView) ServicePortRange() []tailcfg.ProtoPortRange {
+	if v.Tun() {
+		// If the service is in Tun mode, means service accept TCP/UDP on all ports.
+		return []tailcfg.ProtoPortRange{{Ports: tailcfg.PortRangeAny}}
+	}
+	tcp := int(ipproto.TCP)
+
+	// Deduplicate the ports.
+	servePorts := make(set.Set[uint16])
+	for port := range v.TCP().All() {
+		if port > 0 {
+			servePorts.Add(uint16(port))
+		}
+	}
+	dedupedServePorts := servePorts.Slice()
+	slices.Sort(dedupedServePorts)
+
+	var ranges []tailcfg.ProtoPortRange
+	for _, p := range dedupedServePorts {
+		if n := len(ranges); n > 0 && p == ranges[n-1].Ports.Last+1 {
+			ranges[n-1].Ports.Last = p
+			continue
+		}
+		ranges = append(ranges, tailcfg.ProtoPortRange{
+			Proto: tcp,
+			Ports: tailcfg.PortRange{
+				First: p,
+				Last:  p,
+			},
+		})
+	}
+	return ranges
+}