Trojan-UoT & UDP-nameserver: Fix forgotten release buffer; UDP dispatcher: Simplified and optimized (#5050)

transport/pipe/impl.go

@@ -200,16 +200,19 @@ func (p *pipe) Interrupt() {
 	p.Lock()
 	defer p.Unlock()
 
+	if !p.data.IsEmpty() {
+		buf.ReleaseMulti(p.data)
+		p.data = nil
+		if p.state == closed {
+			p.state = errord
+		}
+	}
+
 	if p.state == closed || p.state == errord {
 		return
 	}
 
 	p.state = errord
 
-	if !p.data.IsEmpty() {
-		buf.ReleaseMulti(p.data)
-		p.data = nil
-	}
-
 	common.Must(p.done.Close())
 }