[client] Cleanup firewall state on startup (#2768)

client/internal/routemanager/refcounter/refcounter.go

@@ -1,6 +1,7 @@
 package refcounter
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"runtime"
@@ -70,6 +71,19 @@ func New[Key comparable, I, O any](add AddFunc[Key, I, O], remove RemoveFunc[Key
 	}
 }
 
+// LoadData loads the data from the existing counter
+func (rm *Counter[Key, I, O]) LoadData(
+	existingCounter *Counter[Key, I, O],
+) {
+	rm.refCountMu.Lock()
+	defer rm.refCountMu.Unlock()
+	rm.idMu.Lock()
+	defer rm.idMu.Unlock()
+
+	rm.refCountMap = existingCounter.refCountMap
+	rm.idMap = existingCounter.idMap
+}
+
 // Get retrieves the current reference count and associated data for a key.
 // If the key doesn't exist, it returns a zero value Ref and false.
 func (rm *Counter[Key, I, O]) Get(key Key) (Ref[O], bool) {
@@ -201,6 +215,32 @@ func (rm *Counter[Key, I, O]) Clear() {
 	clear(rm.idMap)
 }
 
+// MarshalJSON implements the json.Marshaler interface for Counter.
+func (rm *Counter[Key, I, O]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(struct {
+		RefCountMap map[Key]Ref[O]   `json:"refCountMap"`
+		IDMap       map[string][]Key `json:"idMap"`
+	}{
+		RefCountMap: rm.refCountMap,
+		IDMap:       rm.idMap,
+	})
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface for Counter.
+func (rm *Counter[Key, I, O]) UnmarshalJSON(data []byte) error {
+	var temp struct {
+		RefCountMap map[Key]Ref[O]   `json:"refCountMap"`
+		IDMap       map[string][]Key `json:"idMap"`
+	}
+	if err := json.Unmarshal(data, &temp); err != nil {
+		return err
+	}
+	rm.refCountMap = temp.RefCountMap
+	rm.idMap = temp.IDMap
+
+	return nil
+}
+
 func getCallerInfo(depth int, maxDepth int) (string, bool) {
 	if depth >= maxDepth {
 		return "", false