Signed-off-by: arraykeys@gmail.com <arraykeys@gmail.com>

CHANGELOG

@@ -1,7 +1,9 @@
 proxy更新日志
 v3.4
 1.tcp代理增加了kcp协议传输数据.
-
+2.优化了死循环检查,增加了添加本地IP参数,当VPS在nat设备后面,
+  vps上网卡IP都是内网IP,这个时候可以通过-g参数添加vps的外网ip防止死循环.
+  
 v3.4
 1.socks5代理新增了用户名密码验证支持.
 2.socks5,http(s)代理增加了kcp传输协议支持.

README.md

@@ -41,6 +41,7 @@ Proxy是golang实现的高性能http,https,websocket,tcp,udp,socks5代理服务
 - [环境](#使用教程)
 - [使用配置文件](#使用配置文件)
 - [生成通讯证书文件](#生成加密通讯需要的证书文件)
+- [安全建议](#安全建议)
 
 ### 手册目录
 - [1. HTTP代理](#1http代理)
@@ -149,6 +150,11 @@ http,tcp,udp代理过程会和上级通讯,为了安全我们采用加密通讯,
 `./proxy keygen`  
 默认会在当前程序目录下面生成证书文件proxy.crt和key文件proxy.key。  
   
+### 安全建议
+当VPS在nat设备后面,vps上网卡IP都是内网IP,这个时候可以通过-g参数添加vps的外网ip防止死循环.
+假设你的vps外网ip是23.23.23.23,下面命令通过-g参数设置23.23.23.23
+`./proxy http -g "23.23.23.23"`  
+
 ### 1.HTTP代理  
 #### **1.1.普通HTTP代理**  
 `./proxy http -t tcp -p "0.0.0.0:38080"`  

config.go

@@ -60,6 +60,7 @@ func initConfig() (err error) {
 	httpArgs.SSHPassword = http.Flag("ssh-password", "password for ssh").Short('A').Default("").String()
 	httpArgs.KCPKey = http.Flag("kcp-key", "key for kcp encrypt/decrypt data").Short('B').Default("encrypt").String()
 	httpArgs.KCPMethod = http.Flag("kcp-method", "kcp encrypt/decrypt method").Short('M').Default("3des").String()
+	httpArgs.LocalIPS = http.Flag("local bind ips", "if your host behind a nat,set your public ip here avoid dead loop").Short('g').Strings()
 
 	//########tcp#########
 	tcp := app.Command("tcp", "proxy on tcp mode")
@@ -134,6 +135,7 @@ func initConfig() (err error) {
 	socksArgs.Auth = socks.Flag("auth", "socks auth username and password, mutiple user repeat -a ,such as: -a user1:pass1 -a user2:pass2").Short('a').Strings()
 	socksArgs.KCPKey = socks.Flag("kcp-key", "key for kcp encrypt/decrypt data").Short('B').Default("encrypt").String()
 	socksArgs.KCPMethod = socks.Flag("kcp-method", "kcp encrypt/decrypt method").Short('M').Default("3des").String()
+	socksArgs.LocalIPS = socks.Flag("local bind ips", "if your host behind a nat,set your public ip here avoid dead loop").Short('g').Strings()
 
 	//parse args
 	serviceName := kingpin.MustParse(app.Parse(os.Args[1:]))

services/args.go

@@ -93,6 +93,7 @@ type HTTPArgs struct {
 	SSHAuthMethod       ssh.AuthMethod
 	KCPMethod           *string
 	KCPKey              *string
+	LocalIPS            *[]string
 }
 type UDPArgs struct {
 	Parent              *string
@@ -132,6 +133,7 @@ type SocksArgs struct {
 	KCPKey         *string
 	UDPParent      *string
 	UDPLocal       *string
+	LocalIPS       *[]string
 }
 
 func (a *TCPArgs) Protocol() string {

services/http.go

@@ -362,6 +362,9 @@ func (s *HTTP) IsDeadLoop(inLocalAddr string, host string) bool {
 			}
 		}
 		interfaceIPs, err := utils.GetAllInterfaceAddr()
+		for _, ip := range *s.cfg.LocalIPS {
+			interfaceIPs = append(interfaceIPs, net.ParseIP(ip).To4())
+		}
 		if err == nil {
 			for _, localIP := range interfaceIPs {
 				for _, outIP := range outIPs {

services/socks.go

@@ -167,6 +167,11 @@ func (s *Socks) udpCallback(b []byte, localAddr, srcAddr *net.UDPAddr) {
 		log.Printf("parse udp packet fail, ERR:%s", err)
 		return
 	}
+	//防止死循环
+	if s.IsDeadLoop((*localAddr).String(), p.Host()) {
+		log.Printf("dead loop detected , %s", p.Host())
+		return
+	}
 	//log.Printf("##########udp to -> %s:%s###########", p.Host(), p.Port())
 	if *s.cfg.Parent != "" {
 		//有上级代理,转发给上级
@@ -398,6 +403,13 @@ func (s *Socks) proxyTCP(inConn *net.Conn, methodReq socks.MethodsRequest, reque
 	useProxy := true
 	tryCount := 0
 	maxTryCount := 5
+	//防止死循环
+	if s.IsDeadLoop((*inConn).LocalAddr().String(), request.Host()) {
+		utils.CloseConn(inConn)
+		log.Printf("dead loop detected , %s", request.Host())
+		utils.CloseConn(inConn)
+		return
+	}
 	for {
 		if *s.cfg.Always {
 			outConn, err = s.getOutConn(methodReq.Bytes(), request.Bytes(), request.Addr())
@@ -568,3 +580,38 @@ func (s *Socks) InitBasicAuth() (err error) {
 func (s *Socks) IsBasicAuth() bool {
 	return *s.cfg.AuthFile != "" || len(*s.cfg.Auth) > 0
 }
+func (s *Socks) IsDeadLoop(inLocalAddr string, host string) bool {
+	inIP, inPort, err := net.SplitHostPort(inLocalAddr)
+	if err != nil {
+		return false
+	}
+	outDomain, outPort, err := net.SplitHostPort(host)
+	if err != nil {
+		return false
+	}
+	if inPort == outPort {
+		var outIPs []net.IP
+		outIPs, err = net.LookupIP(outDomain)
+		if err == nil {
+			for _, ip := range outIPs {
+				if ip.String() == inIP {
+					return true
+				}
+			}
+		}
+		interfaceIPs, err := utils.GetAllInterfaceAddr()
+		for _, ip := range *s.cfg.LocalIPS {
+			interfaceIPs = append(interfaceIPs, net.ParseIP(ip).To4())
+		}
+		if err == nil {
+			for _, localIP := range interfaceIPs {
+				for _, outIP := range outIPs {
+					if localIP.Equal(outIP) {
+						return true
+					}
+				}
+			}
+		}
+	}
+	return false
+}