From a0d08e49616bc907c5ccf85869256f56fd8bce74 Mon Sep 17 00:00:00 2001
From: v2ray <admin@v2ray.com>
Date: Sat, 18 Jun 2016 17:14:39 +0200
Subject: [PATCH] check mtu setting

---
 transport/internet/kcp/config_json.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/transport/internet/kcp/config_json.go b/transport/internet/kcp/config_json.go
index f604f10aa..3d6aa6e6f 100644
--- a/transport/internet/kcp/config_json.go
+++ b/transport/internet/kcp/config_json.go
@@ -4,6 +4,9 @@ package kcp
 
 import (
 	"encoding/json"
+	"errors"
+
+	"github.com/v2ray/v2ray-core/common/log"
 )
 
 func (this *Config) UnmarshalJSON(data []byte) error {
@@ -15,6 +18,11 @@ func (this *Config) UnmarshalJSON(data []byte) error {
 		return err
 	}
 	if jsonConfig.Mtu != nil {
+		mtu := *jsonConfig.Mtu
+		if mtu < 576 || mtu > 1460 {
+			log.Error("KCP|Config: Invalid MTU size: ", mtu)
+			return errors.New("Invalid configuration")
+		}
 		this.Mtu = *jsonConfig.Mtu
 	}