Add admin panel, manager, node_manager, bandwidth limiter, connection limiter, bonding, failover, vless encryption, mkcp transport

protocol/limiter/connection/lock.go

@@ -0,0 +1,37 @@
+package connection
+
+import (
+	"context"
+	"sync"
+
+	E "github.com/sagernet/sing/common/exceptions"
+)
+
+func NewDefaultLock(max uint32) LockIDGetter {
+	locks := make(map[string]*uint32)
+	mtx := sync.Mutex{}
+	return func(id string) (CloseHandlerFunc, context.Context, error) {
+		mtx.Lock()
+		defer mtx.Unlock()
+		handles, ok := locks[id]
+		if !ok {
+			if len(locks) == int(max) {
+				return nil, nil, E.New("not enough free locks")
+			}
+			handles = new(uint32)
+			locks[id] = handles
+		}
+		*handles++
+		var once sync.Once
+		return func() {
+			once.Do(func() {
+				mtx.Lock()
+				defer mtx.Unlock()
+				*handles--
+				if *handles == 0 {
+					delete(locks, id)
+				}
+			})
+		}, nil, nil
+	}
+}