feat: add TURN domain configuration and certificate provisioning via Caddy

docs/WEBRTC.md

@@ -72,18 +72,37 @@ orama namespace disable webrtc --namespace myapp
 
 ## Client Integration (JavaScript)
 
+### Authentication
+
+All WebRTC endpoints require authentication. Use one of:
+
+```
+# Option A: API Key via header (recommended)
+X-API-Key: <your-namespace-api-key>
+
+# Option B: API Key via Authorization header
+Authorization: ApiKey <your-namespace-api-key>
+
+# Option C: JWT Bearer token
+Authorization: Bearer <jwt>
+```
+
 ### 1. Get TURN Credentials
 
 ```javascript
-const response = await fetch('https://ns-myapp.orama.network/v1/webrtc/turn/credentials', {
+const response = await fetch('https://ns-myapp.orama-devnet.network/v1/webrtc/turn/credentials', {
   method: 'POST',
-  headers: { 'Authorization': `Bearer ${jwt}` }
+  headers: { 'X-API-Key': apiKey }
 });
 
-const { urls, username, credential, ttl } = await response.json();
+const { uris, username, password, ttl } = await response.json();
-// urls: ["turn:1.2.3.4:3478?transport=udp", "turns:1.2.3.4:443?transport=udp"]
+// uris: [
+//   "turn:turn.ns-myapp.orama-devnet.network:3478?transport=udp",
+//   "turn:turn.ns-myapp.orama-devnet.network:3478?transport=tcp",
+//   "turns:turn.ns-myapp.orama-devnet.network:5349"
+// ]
 // username: "{expiry_unix}:{namespace}"
-// credential: HMAC-SHA1 derived
+// password: HMAC-SHA1 derived (base64)
 // ttl: 600 (seconds)
 ```
 
@@ -91,7 +110,7 @@ const { urls, username, credential, ttl } = await response.json();
 
 ```javascript
 const pc = new RTCPeerConnection({
-  iceServers: [{ urls, username, credential }],
+  iceServers: [{ urls: uris, username, credential: password }],
   iceTransportPolicy: 'relay'  // enforced by SFU
 });
 ```
@@ -100,8 +119,7 @@ const pc = new RTCPeerConnection({
 
 ```javascript
 const ws = new WebSocket(
-  `wss://ns-myapp.orama.network/v1/webrtc/signal?room=${roomId}`,
+  `wss://ns-myapp.orama-devnet.network/v1/webrtc/signal?room=${roomId}&api_key=${apiKey}`
-  ['Bearer', jwt]
 );
 
 ws.onmessage = (event) => {
@@ -126,22 +144,22 @@ ws.onmessage = (event) => {
 ### 4. Room Management (REST)
 
 ```javascript
+const headers = { 'X-API-Key': apiKey, 'Content-Type': 'application/json' };
+
 // Create room
 await fetch('/v1/webrtc/rooms', {
   method: 'POST',
-  headers: { 'Authorization': `Bearer ${jwt}`, 'Content-Type': 'application/json' },
+  headers,
   body: JSON.stringify({ room_id: 'my-room' })
 });
 
 // List rooms
-const rooms = await fetch('/v1/webrtc/rooms', {
+const rooms = await fetch('/v1/webrtc/rooms', { headers });
-  headers: { 'Authorization': `Bearer ${jwt}` }
-});
 
 // Close room
 await fetch('/v1/webrtc/rooms?room_id=my-room', {
   method: 'DELETE',
-  headers: { 'Authorization': `Bearer ${jwt}` }
+  headers
 });
 ```
 
@@ -176,22 +194,32 @@ await fetch('/v1/webrtc/rooms?room_id=my-room', {
 
 WebRTC uses a **separate port allocation system** from the core namespace ports:
 
-| Service | Port Range | Per Namespace |
+| Service | Port Range | Protocol | Per Namespace |
-|---------|-----------|---------------|
+|---------|-----------|----------|---------------|
-| SFU signaling | 30000-30099 | 1 port |
+| SFU signaling | 30000-30099 | TCP (WireGuard only) | 1 port |
-| SFU media (RTP) | 20000-29999 | 500 ports |
+| SFU media (RTP) | 20000-29999 | UDP (WireGuard only) | 500 ports |
-| TURN listen | 3478 (standard) | fixed |
+| TURN listen | 3478 | UDP + TCP | fixed |
-| TURN TLS | 443/udp (standard) | fixed |
+| TURNS (TLS) | 5349 | TCP | fixed |
-| TURN relay | 49152-65535 | 800 ports |
+| TURN relay | 49152-65535 | UDP | 800 ports |
 
 ## TURN Credential Protocol
 
 - Credentials use HMAC-SHA1 with a per-namespace shared secret
 - Username format: `{expiry_unix}:{namespace}`
+- Password: `base64(HMAC-SHA1(shared_secret, username))`
 - Default TTL: 600 seconds (10 minutes)
 - SFU proactively sends `refresh-credentials` at 80% of TTL (8 minutes)
 - Clients should update ICE servers on receiving refresh
 
+## TURNS TLS Certificate
+
+TURNS (port 5349) uses TLS. Certificate provisioning:
+
+1. **Let's Encrypt (primary)**: On TURN spawn, the TURN domain is added to the local Caddy instance's Caddyfile. Caddy provisions a Let's Encrypt cert via DNS-01 ACME challenge (using the orama DNS provider). TURN reads the cert from Caddy's storage.
+2. **Self-signed (fallback)**: If Caddy cert provisioning fails (timeout, Caddy not running), a self-signed cert is generated with the node's public IP as SAN.
+
+Caddy auto-renews Let's Encrypt certs at ~60 days. TURN picks up renewed certs on restart.
+
 ## Monitoring
 
 ```bash
@@ -226,19 +254,20 @@ systemctl status orama-namespace-turn@myapp
 - **Forced relay**: `iceTransportPolicy: relay` enforced server-side. Clients cannot bypass TURN.
 - **HMAC credentials**: Per-namespace TURN shared secret. Credentials expire after 10 minutes.
 - **Namespace isolation**: Each namespace has its own TURN secret, port ranges, and rooms.
-- **Authentication required**: All WebRTC endpoints require JWT or API key (not in `isPublicPath()`).
+- **Authentication required**: All WebRTC endpoints require API key or JWT (`X-API-Key` header, `Authorization: ApiKey`, or `Authorization: Bearer`).
 - **Room management**: Creating/closing rooms requires namespace ownership.
 - **SFU on WireGuard only**: SFU binds to 10.0.0.x, never 0.0.0.0. Only reachable via TURN relay.
 - **Permissions-Policy**: `camera=(self), microphone=(self)` — only same-origin can access media devices.
 
 ## Firewall
 
-When WebRTC is enabled, the following ports are opened via UFW:
+When WebRTC is enabled, the following ports are opened via UFW on TURN nodes:
 
 | Port | Protocol | Purpose |
 |------|----------|---------|
 | 3478 | UDP | TURN standard |
-| 443 | UDP | TURN TLS (does not conflict with Caddy TCP 443) |
+| 3478 | TCP | TURN TCP fallback (for clients behind UDP-blocking firewalls) |
+| 5349 | TCP | TURNS — TURN over TLS (encrypted, works through strict firewalls/DPI) |
 | 49152-65535 | UDP | TURN relay range (allocated per namespace) |
 
 SFU ports are NOT opened in the firewall — they are WireGuard-internal only.

pkg/gateway/handlers/namespace/spawn_handler.go

@@ -71,6 +71,7 @@ type SpawnRequest struct {
 	TURNAuthSecret  string `json:"turn_auth_secret,omitempty"`
 	TURNRelayStart  int    `json:"turn_relay_start,omitempty"`
 	TURNRelayEnd    int    `json:"turn_relay_end,omitempty"`
+	TURNDomain      string `json:"turn_domain,omitempty"`
 
 	// Cluster state (when action = "save-cluster-state")
 	ClusterState json.RawMessage `json:"cluster_state,omitempty"`
@@ -344,15 +345,16 @@ func (h *SpawnHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 
 	case "spawn-turn":
 		cfg := namespacepkg.TURNInstanceConfig{
-			Namespace:      req.Namespace,
+			Namespace:       req.Namespace,
-			NodeID:         req.NodeID,
+			NodeID:          req.NodeID,
-			ListenAddr:     req.TURNListenAddr,
+			ListenAddr:      req.TURNListenAddr,
 			TURNSListenAddr: req.TURNTURNSAddr,
-			PublicIP:       req.TURNPublicIP,
+			PublicIP:        req.TURNPublicIP,
-			Realm:          req.TURNRealm,
+			Realm:           req.TURNRealm,
-			AuthSecret:     req.TURNAuthSecret,
+			AuthSecret:      req.TURNAuthSecret,
-			RelayPortStart: req.TURNRelayStart,
+			RelayPortStart:  req.TURNRelayStart,
-			RelayPortEnd:   req.TURNRelayEnd,
+			RelayPortEnd:    req.TURNRelayEnd,
+			TURNDomain:      req.TURNDomain,
 		}
 		if err := h.systemdSpawner.SpawnTURN(ctx, req.Namespace, req.NodeID, cfg); err != nil {
 			h.logger.Error("Failed to spawn TURN instance", zap.Error(err))

pkg/namespace/cluster_manager.go

@@ -1965,6 +1965,7 @@ func (cm *ClusterManager) restoreClusterFromState(ctx context.Context, state *Cl
 					AuthSecret:      webrtcCfg.TURNSharedSecret,
 					RelayPortStart:  state.TURNRelayPortStart,
 					RelayPortEnd:    state.TURNRelayPortEnd,
+					TURNDomain:      fmt.Sprintf("turn.ns-%s.%s", state.NamespaceName, cm.baseDomain),
 				}
 				if err := cm.systemdSpawner.SpawnTURN(ctx, state.NamespaceName, cm.localNodeID, turnCfg); err != nil {
 					cm.logger.Error("Failed to restore TURN from state", zap.String("namespace", state.NamespaceName), zap.Error(err))

pkg/namespace/cluster_manager_webrtc.go

@@ -132,6 +132,7 @@ func (cm *ClusterManager) EnableWebRTC(ctx context.Context, namespaceName, enabl
 			AuthSecret:      turnSecret,
 			RelayPortStart:  turnBlock.TURNRelayPortStart,
 			RelayPortEnd:    turnBlock.TURNRelayPortEnd,
+			TURNDomain:      turnDomain,
 		}
 
 		if err := cm.spawnTURNOnNode(ctx, node, namespaceName, turnCfg); err != nil {
@@ -474,6 +475,7 @@ func (cm *ClusterManager) spawnTURNRemote(ctx context.Context, nodeIP string, cf
 		"turn_auth_secret":  cfg.AuthSecret,
 		"turn_relay_start":  cfg.RelayPortStart,
 		"turn_relay_end":    cfg.RelayPortEnd,
+		"turn_domain":       cfg.TURNDomain,
 	})
 	return err
 }

pkg/namespace/systemd_spawner.go

@@ -402,6 +402,7 @@ type TURNInstanceConfig struct {
 	AuthSecret      string // HMAC-SHA1 shared secret
 	RelayPortStart  int    // Start of relay port range
 	RelayPortEnd    int    // End of relay port range
+	TURNDomain      string // TURN domain for Let's Encrypt cert (e.g., "turn.ns-myapp.orama-devnet.network")
 }
 
 // SpawnTURN starts a TURN instance using systemd
@@ -420,20 +421,41 @@ func (s *SystemdSpawner) SpawnTURN(ctx context.Context, namespace, nodeID string
 
 	configPath := filepath.Join(configDir, fmt.Sprintf("turn-%s.yaml", nodeID))
 
-	// Generate self-signed TLS cert for TURNS if not already present
+	// Provision TLS cert for TURNS — try Let's Encrypt via Caddy first, fall back to self-signed
 	certPath := filepath.Join(configDir, "turn-cert.pem")
 	keyPath := filepath.Join(configDir, "turn-key.pem")
 	if cfg.TURNSListenAddr != "" {
 		if _, err := os.Stat(certPath); os.IsNotExist(err) {
-			if err := turn.GenerateSelfSignedCert(certPath, keyPath, cfg.PublicIP); err != nil {
+			// Try Let's Encrypt via Caddy first
-				s.logger.Warn("Failed to generate TURNS self-signed cert, TURNS will be disabled",
+			if cfg.TURNDomain != "" {
-					zap.String("namespace", namespace),
+				acmeEndpoint := "http://localhost:6001/v1/internal/acme"
-					zap.Error(err))
+				caddyCert, caddyKey, provErr := provisionTURNCertViaCaddy(cfg.TURNDomain, acmeEndpoint, 2*time.Minute)
-				cfg.TURNSListenAddr = "" // Disable TURNS if cert generation fails
+				if provErr == nil {
-			} else {
+					certPath = caddyCert
-				s.logger.Info("Generated TURNS self-signed certificate",
+					keyPath = caddyKey
-					zap.String("namespace", namespace),
+					s.logger.Info("Using Let's Encrypt cert from Caddy for TURNS",
-					zap.String("cert_path", certPath))
+						zap.String("namespace", namespace),
+						zap.String("domain", cfg.TURNDomain),
+						zap.String("cert_path", certPath))
+				} else {
+					s.logger.Warn("Let's Encrypt cert provisioning failed, falling back to self-signed",
+						zap.String("namespace", namespace),
+						zap.String("domain", cfg.TURNDomain),
+						zap.Error(provErr))
+				}
+			}
+			// Fallback: generate self-signed cert if no cert is available yet
+			if _, statErr := os.Stat(certPath); os.IsNotExist(statErr) {
+				if err := turn.GenerateSelfSignedCert(certPath, keyPath, cfg.PublicIP); err != nil {
+					s.logger.Warn("Failed to generate TURNS self-signed cert, TURNS will be disabled",
+						zap.String("namespace", namespace),
+						zap.Error(err))
+					cfg.TURNSListenAddr = "" // Disable TURNS if cert generation fails
+				} else {
+					s.logger.Info("Generated TURNS self-signed certificate",
+						zap.String("namespace", namespace),
+						zap.String("cert_path", certPath))
+				}
 			}
 		}
 	}
@@ -518,6 +540,22 @@ func (s *SystemdSpawner) StopTURN(ctx context.Context, namespace, nodeID string)
 			zap.Error(fwErr))
 	}
 
+	// Remove TURN cert block from Caddyfile (if provisioned via Let's Encrypt)
+	configDir := filepath.Join(s.namespaceBase, namespace, "configs")
+	configPath := filepath.Join(configDir, fmt.Sprintf("turn-%s.yaml", nodeID))
+	if data, readErr := os.ReadFile(configPath); readErr == nil {
+		var turnCfg turn.Config
+		if yaml.Unmarshal(data, &turnCfg) == nil && turnCfg.Realm != "" {
+			turnDomain := fmt.Sprintf("turn.ns-%s.%s", namespace, turnCfg.Realm)
+			if removeErr := removeTURNCertFromCaddy(turnDomain); removeErr != nil {
+				s.logger.Warn("Failed to remove TURN cert from Caddyfile",
+					zap.String("namespace", namespace),
+					zap.String("domain", turnDomain),
+					zap.Error(removeErr))
+			}
+		}
+	}
+
 	return err
 }
 

pkg/namespace/turn_cert.go

@@ -0,0 +1,165 @@
+package namespace
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+)
+
+const (
+	caddyfilePath = "/etc/caddy/Caddyfile"
+
+	// Caddy stores ACME certs under this directory relative to its data dir.
+	caddyACMECertDir = "certificates/acme-v02.api.letsencrypt.org-directory"
+
+	turnCertBeginMarker = "# BEGIN TURN CERT: "
+	turnCertEndMarker   = "# END TURN CERT: "
+)
+
+// provisionTURNCertViaCaddy appends the TURN domain to the local Caddyfile,
+// reloads Caddy to trigger DNS-01 ACME certificate provisioning, and waits
+// for the cert files to appear. Returns the cert/key paths on success.
+// If Caddy is not available or cert provisioning times out, returns an error
+// so the caller can fall back to a self-signed cert.
+func provisionTURNCertViaCaddy(domain, acmeEndpoint string, timeout time.Duration) (certPath, keyPath string, err error) {
+	// Check if cert already exists from a previous provisioning
+	certPath, keyPath = caddyCertPaths(domain)
+	if _, err := os.Stat(certPath); err == nil {
+		return certPath, keyPath, nil
+	}
+
+	// Read current Caddyfile
+	data, err := os.ReadFile(caddyfilePath)
+	if err != nil {
+		return "", "", fmt.Errorf("failed to read Caddyfile: %w", err)
+	}
+
+	caddyfile := string(data)
+
+	// Check if domain block already exists (idempotent)
+	marker := turnCertBeginMarker + domain
+	if strings.Contains(caddyfile, marker) {
+		// Block already present — just wait for cert
+		return waitForCaddyCert(domain, timeout)
+	}
+
+	// Append a minimal Caddyfile block for the TURN domain
+	block := fmt.Sprintf(`
+%s%s
+%s {
+    tls {
+        issuer acme {
+            dns orama {
+                endpoint %s
+            }
+        }
+    }
+    respond "OK" 200
+}
+%s%s
+`, turnCertBeginMarker, domain, domain, acmeEndpoint, turnCertEndMarker, domain)
+
+	if err := os.WriteFile(caddyfilePath, []byte(caddyfile+block), 0644); err != nil {
+		return "", "", fmt.Errorf("failed to write Caddyfile: %w", err)
+	}
+
+	// Reload Caddy to pick up the new domain
+	if err := reloadCaddy(); err != nil {
+		return "", "", fmt.Errorf("failed to reload Caddy: %w", err)
+	}
+
+	// Wait for cert to be provisioned
+	return waitForCaddyCert(domain, timeout)
+}
+
+// removeTURNCertFromCaddy removes the TURN domain block from the Caddyfile
+// and reloads Caddy. Safe to call even if the block doesn't exist.
+func removeTURNCertFromCaddy(domain string) error {
+	data, err := os.ReadFile(caddyfilePath)
+	if err != nil {
+		return fmt.Errorf("failed to read Caddyfile: %w", err)
+	}
+
+	caddyfile := string(data)
+	beginMarker := turnCertBeginMarker + domain
+	endMarker := turnCertEndMarker + domain
+
+	beginIdx := strings.Index(caddyfile, beginMarker)
+	if beginIdx == -1 {
+		return nil // Block not found, nothing to remove
+	}
+
+	endIdx := strings.Index(caddyfile, endMarker)
+	if endIdx == -1 {
+		return nil // Malformed markers, skip
+	}
+
+	// Include the end marker line itself
+	endIdx += len(endMarker)
+	// Also consume the trailing newline if present
+	if endIdx < len(caddyfile) && caddyfile[endIdx] == '\n' {
+		endIdx++
+	}
+
+	// Remove leading newline before the begin marker if present
+	if beginIdx > 0 && caddyfile[beginIdx-1] == '\n' {
+		beginIdx--
+	}
+
+	newCaddyfile := caddyfile[:beginIdx] + caddyfile[endIdx:]
+	if err := os.WriteFile(caddyfilePath, []byte(newCaddyfile), 0644); err != nil {
+		return fmt.Errorf("failed to write Caddyfile: %w", err)
+	}
+
+	return reloadCaddy()
+}
+
+// caddyCertPaths returns the expected cert and key file paths in Caddy's
+// storage for a given domain. Caddy stores ACME certs as standard PEM files.
+func caddyCertPaths(domain string) (certPath, keyPath string) {
+	dataDir := caddyDataDir()
+	certDir := filepath.Join(dataDir, caddyACMECertDir, domain)
+	return filepath.Join(certDir, domain+".crt"), filepath.Join(certDir, domain+".key")
+}
+
+// caddyDataDir returns Caddy's data directory. Caddy uses XDG_DATA_HOME/caddy
+// if set, otherwise falls back to $HOME/.local/share/caddy.
+func caddyDataDir() string {
+	if xdg := os.Getenv("XDG_DATA_HOME"); xdg != "" {
+		return filepath.Join(xdg, "caddy")
+	}
+	home := os.Getenv("HOME")
+	if home == "" {
+		home = "/root" // Caddy runs as root in our setup
+	}
+	return filepath.Join(home, ".local", "share", "caddy")
+}
+
+// waitForCaddyCert polls for the cert file to appear with a timeout.
+func waitForCaddyCert(domain string, timeout time.Duration) (string, string, error) {
+	certPath, keyPath := caddyCertPaths(domain)
+	deadline := time.Now().Add(timeout)
+
+	for time.Now().Before(deadline) {
+		if _, err := os.Stat(certPath); err == nil {
+			if _, err := os.Stat(keyPath); err == nil {
+				return certPath, keyPath, nil
+			}
+		}
+		time.Sleep(5 * time.Second)
+	}
+
+	return "", "", fmt.Errorf("timed out waiting for Caddy to provision cert for %s (checked %s)", domain, certPath)
+}
+
+// reloadCaddy sends a reload signal to Caddy via systemctl.
+func reloadCaddy() error {
+	cmd := exec.Command("systemctl", "reload", "caddy")
+	if output, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("systemctl reload caddy failed: %w (%s)", err, strings.TrimSpace(string(output)))
+	}
+	return nil
+}

pkg/namespace/turn_cert_test.go

@@ -0,0 +1,204 @@
+package namespace
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestCaddyCertPaths(t *testing.T) {
+	// Override HOME for deterministic test
+	origHome := os.Getenv("HOME")
+	origXDG := os.Getenv("XDG_DATA_HOME")
+	defer func() {
+		os.Setenv("HOME", origHome)
+		os.Setenv("XDG_DATA_HOME", origXDG)
+	}()
+
+	t.Run("default HOME path", func(t *testing.T) {
+		os.Setenv("HOME", "/root")
+		os.Unsetenv("XDG_DATA_HOME")
+
+		certPath, keyPath := caddyCertPaths("turn.ns-test.example.com")
+
+		expectedCert := "/root/.local/share/caddy/certificates/acme-v02.api.letsencrypt.org-directory/turn.ns-test.example.com/turn.ns-test.example.com.crt"
+		expectedKey := "/root/.local/share/caddy/certificates/acme-v02.api.letsencrypt.org-directory/turn.ns-test.example.com/turn.ns-test.example.com.key"
+
+		if certPath != expectedCert {
+			t.Errorf("cert path = %q, want %q", certPath, expectedCert)
+		}
+		if keyPath != expectedKey {
+			t.Errorf("key path = %q, want %q", keyPath, expectedKey)
+		}
+	})
+
+	t.Run("XDG_DATA_HOME override", func(t *testing.T) {
+		os.Setenv("XDG_DATA_HOME", "/custom/data")
+		certPath, keyPath := caddyCertPaths("turn.ns-test.example.com")
+
+		expectedCert := "/custom/data/caddy/certificates/acme-v02.api.letsencrypt.org-directory/turn.ns-test.example.com/turn.ns-test.example.com.crt"
+		expectedKey := "/custom/data/caddy/certificates/acme-v02.api.letsencrypt.org-directory/turn.ns-test.example.com/turn.ns-test.example.com.key"
+
+		if certPath != expectedCert {
+			t.Errorf("cert path = %q, want %q", certPath, expectedCert)
+		}
+		if keyPath != expectedKey {
+			t.Errorf("key path = %q, want %q", keyPath, expectedKey)
+		}
+	})
+}
+
+func TestRemoveTURNCertFromCaddy_MarkerRemoval(t *testing.T) {
+	// Create a temporary Caddyfile with a TURN cert block
+	tmpDir := t.TempDir()
+	tmpCaddyfile := filepath.Join(tmpDir, "Caddyfile")
+
+	domain := "turn.ns-test.example.com"
+	original := `{
+    email admin@example.com
+}
+
+*.example.com {
+    tls {
+        issuer acme {
+            dns orama {
+                endpoint http://localhost:6001/v1/internal/acme
+            }
+        }
+    }
+    reverse_proxy localhost:6001
+}
+
+# BEGIN TURN CERT: turn.ns-test.example.com
+turn.ns-test.example.com {
+    tls {
+        issuer acme {
+            dns orama {
+                endpoint http://localhost:6001/v1/internal/acme
+            }
+        }
+    }
+    respond "OK" 200
+}
+# END TURN CERT: turn.ns-test.example.com
+`
+
+	if err := os.WriteFile(tmpCaddyfile, []byte(original), 0644); err != nil {
+		t.Fatal(err)
+	}
+
+	// Test the marker removal logic directly (not calling removeTURNCertFromCaddy
+	// because it tries to reload Caddy via systemctl)
+	data, err := os.ReadFile(tmpCaddyfile)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	caddyfile := string(data)
+	beginMarker := turnCertBeginMarker + domain
+	endMarker := turnCertEndMarker + domain
+
+	beginIdx := findIndex(caddyfile, beginMarker)
+	if beginIdx == -1 {
+		t.Fatal("BEGIN marker not found")
+	}
+
+	endIdx := findIndex(caddyfile, endMarker)
+	if endIdx == -1 {
+		t.Fatal("END marker not found")
+	}
+
+	// Include end marker line
+	endIdx += len(endMarker)
+	if endIdx < len(caddyfile) && caddyfile[endIdx] == '\n' {
+		endIdx++
+	}
+
+	// Remove leading newline
+	if beginIdx > 0 && caddyfile[beginIdx-1] == '\n' {
+		beginIdx--
+	}
+
+	result := caddyfile[:beginIdx] + caddyfile[endIdx:]
+
+	// Verify the TURN block is removed
+	if findIndex(result, "TURN CERT") != -1 {
+		t.Error("TURN CERT markers still present after removal")
+	}
+	if findIndex(result, "turn.ns-test.example.com") != -1 {
+		t.Error("TURN domain still present after removal")
+	}
+
+	// Verify the rest of the Caddyfile is intact
+	if findIndex(result, "*.example.com") == -1 {
+		t.Error("wildcard domain block was incorrectly removed")
+	}
+	if findIndex(result, "reverse_proxy localhost:6001") == -1 {
+		t.Error("reverse_proxy directive was incorrectly removed")
+	}
+}
+
+func TestRemoveTURNCertFromCaddy_NoMarkers(t *testing.T) {
+	// When no markers exist, the Caddyfile should be unchanged
+	original := `{
+    email admin@example.com
+}
+
+*.example.com {
+    reverse_proxy localhost:6001
+}
+`
+	caddyfile := original
+	beginMarker := turnCertBeginMarker + "turn.ns-test.example.com"
+
+	beginIdx := findIndex(caddyfile, beginMarker)
+	if beginIdx != -1 {
+		t.Error("expected no BEGIN marker in Caddyfile without TURN block")
+	}
+	// If no marker found, nothing to remove — original unchanged
+}
+
+func TestCaddyDataDir(t *testing.T) {
+	origHome := os.Getenv("HOME")
+	origXDG := os.Getenv("XDG_DATA_HOME")
+	defer func() {
+		os.Setenv("HOME", origHome)
+		os.Setenv("XDG_DATA_HOME", origXDG)
+	}()
+
+	t.Run("XDG set", func(t *testing.T) {
+		os.Setenv("XDG_DATA_HOME", "/xdg/data")
+		got := caddyDataDir()
+		if got != "/xdg/data/caddy" {
+			t.Errorf("caddyDataDir() = %q, want /xdg/data/caddy", got)
+		}
+	})
+
+	t.Run("HOME fallback", func(t *testing.T) {
+		os.Unsetenv("XDG_DATA_HOME")
+		os.Setenv("HOME", "/home/user")
+		got := caddyDataDir()
+		if got != "/home/user/.local/share/caddy" {
+			t.Errorf("caddyDataDir() = %q, want /home/user/.local/share/caddy", got)
+		}
+	})
+
+	t.Run("root fallback", func(t *testing.T) {
+		os.Unsetenv("XDG_DATA_HOME")
+		os.Unsetenv("HOME")
+		got := caddyDataDir()
+		if got != "/root/.local/share/caddy" {
+			t.Errorf("caddyDataDir() = %q, want /root/.local/share/caddy", got)
+		}
+	})
+}
+
+// findIndex returns the index of the first occurrence of substr in s, or -1.
+func findIndex(s, substr string) int {
+	for i := 0; i+len(substr) <= len(s); i++ {
+		if s[i:i+len(substr)] == substr {
+			return i
+		}
+	}
+	return -1
+}