[management, proxy] Add require_subdomain capability for proxy clusters

management/internals/modules/reverseproxy/domain/domain.go

@@ -17,6 +17,9 @@ type Domain struct {
 	// SupportsCustomPorts is populated at query time for free domains from the
 	// proxy cluster capabilities. Not persisted.
 	SupportsCustomPorts *bool `gorm:"-"`
+	// RequireSubdomain is populated at query time. When true, the domain
+	// cannot be used bare and a subdomain label must be prepended. Not persisted.
+	RequireSubdomain *bool `gorm:"-"`
 }
 
 // EventMeta returns activity event metadata for a domain

management/internals/modules/reverseproxy/domain/manager/api.go

@@ -47,6 +47,7 @@ func domainToApi(d *domain.Domain) api.ReverseProxyDomain {
 		Type:                domainTypeToApi(d.Type),
 		Validated:           d.Validated,
 		SupportsCustomPorts: d.SupportsCustomPorts,
+		RequireSubdomain:    d.RequireSubdomain,
 	}
 	if d.TargetCluster != "" {
 		resp.TargetCluster = &d.TargetCluster

management/internals/modules/reverseproxy/domain/manager/domain_test.go

@@ -0,0 +1,172 @@
+package manager
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"github.com/netbirdio/netbird/management/internals/modules/reverseproxy/domain"
+)
+
+func TestExtractClusterFromFreeDomain(t *testing.T) {
+	clusters := []string{"eu1.proxy.netbird.io", "us1.proxy.netbird.io"}
+
+	tests := []struct {
+		name    string
+		domain  string
+		wantOK  bool
+		wantVal string
+	}{
+		{
+			name:    "subdomain of cluster matches",
+			domain:  "myapp.eu1.proxy.netbird.io",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:    "deep subdomain of cluster matches",
+			domain:  "foo.bar.eu1.proxy.netbird.io",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:    "bare cluster domain matches",
+			domain:  "eu1.proxy.netbird.io",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:   "unrelated domain does not match",
+			domain: "example.com",
+			wantOK: false,
+		},
+		{
+			name:   "partial suffix does not match",
+			domain: "fakeu1.proxy.netbird.io",
+			wantOK: false,
+		},
+		{
+			name:    "second cluster matches",
+			domain:  "app.us1.proxy.netbird.io",
+			wantOK:  true,
+			wantVal: "us1.proxy.netbird.io",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cluster, ok := ExtractClusterFromFreeDomain(tc.domain, clusters)
+			assert.Equal(t, tc.wantOK, ok)
+			if ok {
+				assert.Equal(t, tc.wantVal, cluster)
+			}
+		})
+	}
+}
+
+func TestExtractClusterFromCustomDomains(t *testing.T) {
+	customDomains := []*domain.Domain{
+		{Domain: "example.com", TargetCluster: "eu1.proxy.netbird.io"},
+		{Domain: "proxy.corp.io", TargetCluster: "us1.proxy.netbird.io"},
+	}
+
+	tests := []struct {
+		name    string
+		domain  string
+		wantOK  bool
+		wantVal string
+	}{
+		{
+			name:    "subdomain of custom domain matches",
+			domain:  "app.example.com",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:    "bare custom domain matches",
+			domain:  "example.com",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:    "deep subdomain of custom domain matches",
+			domain:  "a.b.example.com",
+			wantOK:  true,
+			wantVal: "eu1.proxy.netbird.io",
+		},
+		{
+			name:    "subdomain of multi-level custom domain matches",
+			domain:  "app.proxy.corp.io",
+			wantOK:  true,
+			wantVal: "us1.proxy.netbird.io",
+		},
+		{
+			name:    "bare multi-level custom domain matches",
+			domain:  "proxy.corp.io",
+			wantOK:  true,
+			wantVal: "us1.proxy.netbird.io",
+		},
+		{
+			name:   "unrelated domain does not match",
+			domain: "other.com",
+			wantOK: false,
+		},
+		{
+			name:   "partial suffix does not match custom domain",
+			domain: "fakeexample.com",
+			wantOK: false,
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cluster, ok := extractClusterFromCustomDomains(tc.domain, customDomains)
+			assert.Equal(t, tc.wantOK, ok)
+			if ok {
+				assert.Equal(t, tc.wantVal, cluster)
+			}
+		})
+	}
+}
+
+func TestExtractClusterFromCustomDomains_OverlappingDomains(t *testing.T) {
+	customDomains := []*domain.Domain{
+		{Domain: "example.com", TargetCluster: "cluster-generic"},
+		{Domain: "app.example.com", TargetCluster: "cluster-app"},
+	}
+
+	tests := []struct {
+		name    string
+		domain  string
+		wantVal string
+	}{
+		{
+			name:    "exact match on more specific domain",
+			domain:  "app.example.com",
+			wantVal: "cluster-app",
+		},
+		{
+			name:    "subdomain of more specific domain",
+			domain:  "api.app.example.com",
+			wantVal: "cluster-app",
+		},
+		{
+			name:    "subdomain of generic domain",
+			domain:  "other.example.com",
+			wantVal: "cluster-generic",
+		},
+		{
+			name:    "bare generic domain",
+			domain:  "example.com",
+			wantVal: "cluster-generic",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			cluster, ok := extractClusterFromCustomDomains(tc.domain, customDomains)
+			assert.True(t, ok)
+			assert.Equal(t, tc.wantVal, cluster)
+		})
+	}
+}

management/internals/modules/reverseproxy/domain/manager/manager.go

@@ -35,6 +35,7 @@ type proxyManager interface {
 
 type clusterCapabilities interface {
 	ClusterSupportsCustomPorts(clusterAddr string) *bool
+	ClusterRequireSubdomain(clusterAddr string) *bool
 }
 
 type Manager struct {
@@ -98,6 +99,7 @@ func (m Manager) GetDomains(ctx context.Context, accountID, userID string) ([]*d
 		}
 		if m.clusterCapabilities != nil {
 			d.SupportsCustomPorts = m.clusterCapabilities.ClusterSupportsCustomPorts(cluster)
+			d.RequireSubdomain = m.clusterCapabilities.ClusterRequireSubdomain(cluster)
 		}
 		ret = append(ret, d)
 	}
@@ -115,6 +117,8 @@ func (m Manager) GetDomains(ctx context.Context, accountID, userID string) ([]*d
 		if m.clusterCapabilities != nil && d.TargetCluster != "" {
 			cd.SupportsCustomPorts = m.clusterCapabilities.ClusterSupportsCustomPorts(d.TargetCluster)
 		}
+		// Custom domains never require a subdomain by default since
+		// the account owns them and should be able to use the bare domain.
 		ret = append(ret, cd)
 	}
 
@@ -302,13 +306,19 @@ func (m Manager) DeriveClusterFromDomain(ctx context.Context, accountID, domain
 	return "", fmt.Errorf("domain %s does not match any available proxy cluster", domain)
 }
 
-func extractClusterFromCustomDomains(domain string, customDomains []*domain.Domain) (string, bool) {
-	for _, customDomain := range customDomains {
-		if strings.HasSuffix(domain, "."+customDomain.Domain) {
-			return customDomain.TargetCluster, true
+func extractClusterFromCustomDomains(serviceDomain string, customDomains []*domain.Domain) (string, bool) {
+	bestCluster := ""
+	bestLen := -1
+	for _, cd := range customDomains {
+		if serviceDomain != cd.Domain && !strings.HasSuffix(serviceDomain, "."+cd.Domain) {
+			continue
+		}
+		if l := len(cd.Domain); l > bestLen {
+			bestLen = l
+			bestCluster = cd.TargetCluster
 		}
 	}
-	return "", false
+	return bestCluster, bestLen >= 0
 }
 
 // ExtractClusterFromFreeDomain extracts the cluster address from a free domain.

management/internals/modules/reverseproxy/proxy/manager.go

@@ -35,4 +35,5 @@ type Controller interface {
 	UnregisterProxyFromCluster(ctx context.Context, clusterAddr, proxyID string) error
 	GetProxiesForCluster(clusterAddr string) []string
 	ClusterSupportsCustomPorts(clusterAddr string) *bool
+	ClusterRequireSubdomain(clusterAddr string) *bool
 }

management/internals/modules/reverseproxy/proxy/manager/controller.go

@@ -77,6 +77,12 @@ func (c *GRPCController) ClusterSupportsCustomPorts(clusterAddr string) *bool {
 	return c.proxyGRPCServer.ClusterSupportsCustomPorts(clusterAddr)
 }
 
+// ClusterRequireSubdomain returns whether the cluster requires a subdomain label.
+// Returns nil when no proxy has reported the capability (defaults to false).
+func (c *GRPCController) ClusterRequireSubdomain(clusterAddr string) *bool {
+	return c.proxyGRPCServer.ClusterRequireSubdomain(clusterAddr)
+}
+
 // GetProxiesForCluster returns all proxy IDs registered for a specific cluster.
 func (c *GRPCController) GetProxiesForCluster(clusterAddr string) []string {
 	proxySet, ok := c.clusterProxies.Load(clusterAddr)

management/internals/modules/reverseproxy/service/manager/l4_port_test.go

@@ -76,6 +76,7 @@ func setupL4Test(t *testing.T, customPortsSupported *bool) (*Manager, store.Stor
 
 	mockCtrl := proxy.NewMockController(ctrl)
 	mockCtrl.EXPECT().ClusterSupportsCustomPorts(gomock.Any()).Return(customPortsSupported).AnyTimes()
+	mockCtrl.EXPECT().ClusterRequireSubdomain(gomock.Any()).Return((*bool)(nil)).AnyTimes()
 	mockCtrl.EXPECT().SendServiceUpdateToCluster(gomock.Any(), gomock.Any(), gomock.Any(), gomock.Any()).AnyTimes()
 	mockCtrl.EXPECT().GetOIDCValidationConfig().Return(proxy.OIDCValidationConfig{}).AnyTimes()