fix: multi issues - TUN read loop, SDWAN routing for TenantID=0, WS keepalive 10s

internal/server/sdwan.go

@@ -12,13 +12,14 @@ import (
 )
 
 type sdwanStore struct {
-	mu   sync.RWMutex
-	path string
-	cfg  protocol.SDWANConfig
+	mu    sync.RWMutex
+	path  string
+	cfg   protocol.SDWANConfig
+	multi map[int64]protocol.SDWANConfig
 }
 
 func newSDWANStore(path string) *sdwanStore {
-	s := &sdwanStore{path: path}
+	s := &sdwanStore{path: path, multi: make(map[int64]protocol.SDWANConfig)}
 	_ = s.load()
 	return s
 }
@@ -33,6 +34,15 @@ func (s *sdwanStore) load() error {
 		}
 		return err
 	}
+	// try multi-tenant first
+	var m map[int64]protocol.SDWANConfig
+	if err := json.Unmarshal(b, &m); err == nil && len(m) > 0 {
+		for k, v := range m {
+			m[k] = normalizeSDWAN(v)
+		}
+		s.multi = m
+		return nil
+	}
 	var c protocol.SDWANConfig
 	if err := json.Unmarshal(b, &c); err != nil {
 		return err
@@ -57,12 +67,40 @@ func (s *sdwanStore) save(cfg protocol.SDWANConfig) error {
 	return nil
 }
 
+func (s *sdwanStore) saveTenant(tenantID int64, cfg protocol.SDWANConfig) error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	cfg = normalizeSDWAN(cfg)
+	cfg.UpdatedAt = time.Now().Unix()
+	if s.multi == nil {
+		s.multi = make(map[int64]protocol.SDWANConfig)
+	}
+	s.multi[tenantID] = cfg
+	b, err := json.MarshalIndent(s.multi, "", "  ")
+	if err != nil {
+		return err
+	}
+	if err := os.WriteFile(s.path, b, 0644); err != nil {
+		return err
+	}
+	return nil
+}
+
 func (s *sdwanStore) get() protocol.SDWANConfig {
 	s.mu.RLock()
 	defer s.mu.RUnlock()
 	return s.cfg
 }
 
+func (s *sdwanStore) getTenant(tenantID int64) protocol.SDWANConfig {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	if s.multi == nil {
+		return protocol.SDWANConfig{}
+	}
+	return s.multi[tenantID]
+}
+
 func normalizeSDWAN(c protocol.SDWANConfig) protocol.SDWANConfig {
 	if c.Mode == "" {
 		c.Mode = "hub"