add rate limiter

admission/wrapper/listener.go

@@ -0,0 +1,37 @@
+package wrapper
+
+import (
+	"net"
+
+	"github.com/go-gost/core/admission"
+)
+
+type listener struct {
+	net.Listener
+	admission admission.Admission
+}
+
+func WrapListener(admission admission.Admission, ln net.Listener) net.Listener {
+	if admission == nil {
+		return ln
+	}
+	return &listener{
+		Listener:  ln,
+		admission: admission,
+	}
+}
+
+func (ln *listener) Accept() (net.Conn, error) {
+	for {
+		c, err := ln.Listener.Accept()
+		if err != nil {
+			return nil, err
+		}
+		if ln.admission != nil &&
+			!ln.admission.Admit(c.RemoteAddr().String()) {
+			c.Close()
+			continue
+		}
+		return c, err
+	}
+}