frp/client/proxy/proxy.go

810 lines
20 KiB
Go

// Copyright 2017 fatedier, fatedier@gmail.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package proxy
import (
"bytes"
"context"
"fmt"
"io"
"net"
"strconv"
"strings"
"sync"
"time"
"github.com/fatedier/frp/pkg/config"
"github.com/fatedier/frp/pkg/msg"
plugin "github.com/fatedier/frp/pkg/plugin/client"
"github.com/fatedier/frp/pkg/proto/udp"
"github.com/fatedier/frp/pkg/util/limit"
frpNet "github.com/fatedier/frp/pkg/util/net"
"github.com/fatedier/frp/pkg/util/xlog"
"github.com/fatedier/golib/errors"
frpIo "github.com/fatedier/golib/io"
"github.com/fatedier/golib/pool"
fmux "github.com/hashicorp/yamux"
pp "github.com/pires/go-proxyproto"
"golang.org/x/time/rate"
)
// Proxy defines how to handle work connections for different proxy type.
type Proxy interface {
Run() error
// InWorkConn accept work connections registered to server.
InWorkConn(net.Conn, *msg.StartWorkConn)
Close()
}
func NewProxy(ctx context.Context, pxyConf config.ProxyConf, clientCfg config.ClientCommonConf, serverUDPPort int) (pxy Proxy) {
var limiter *rate.Limiter
limitBytes := pxyConf.GetBaseInfo().BandwidthLimit.Bytes()
if limitBytes > 0 {
limiter = rate.NewLimiter(rate.Limit(float64(limitBytes)), int(limitBytes))
}
baseProxy := BaseProxy{
clientCfg: clientCfg,
serverUDPPort: serverUDPPort,
limiter: limiter,
xl: xlog.FromContextSafe(ctx),
ctx: ctx,
}
switch cfg := pxyConf.(type) {
case *config.TCPProxyConf:
pxy = &TCPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.TCPMuxProxyConf:
pxy = &TCPMuxProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.UDPProxyConf:
pxy = &UDPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.HTTPProxyConf:
pxy = &HTTPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.HTTPSProxyConf:
pxy = &HTTPSProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.STCPProxyConf:
pxy = &STCPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.XTCPProxyConf:
pxy = &XTCPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
}
case *config.SUDPProxyConf:
pxy = &SUDPProxy{
BaseProxy: &baseProxy,
cfg: cfg,
closeCh: make(chan struct{}),
}
}
return
}
type BaseProxy struct {
closed bool
clientCfg config.ClientCommonConf
serverUDPPort int
limiter *rate.Limiter
mu sync.RWMutex
xl *xlog.Logger
ctx context.Context
}
// TCP
type TCPProxy struct {
*BaseProxy
cfg *config.TCPProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *TCPProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *TCPProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *TCPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
conn, []byte(pxy.clientCfg.Token), m)
}
// TCP Multiplexer
type TCPMuxProxy struct {
*BaseProxy
cfg *config.TCPMuxProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *TCPMuxProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *TCPMuxProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *TCPMuxProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
conn, []byte(pxy.clientCfg.Token), m)
}
// HTTP
type HTTPProxy struct {
*BaseProxy
cfg *config.HTTPProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *HTTPProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *HTTPProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *HTTPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
conn, []byte(pxy.clientCfg.Token), m)
}
// HTTPS
type HTTPSProxy struct {
*BaseProxy
cfg *config.HTTPSProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *HTTPSProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *HTTPSProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *HTTPSProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
conn, []byte(pxy.clientCfg.Token), m)
}
// STCP
type STCPProxy struct {
*BaseProxy
cfg *config.STCPProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *STCPProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *STCPProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *STCPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
conn, []byte(pxy.clientCfg.Token), m)
}
// XTCP
type XTCPProxy struct {
*BaseProxy
cfg *config.XTCPProxyConf
proxyPlugin plugin.Plugin
}
func (pxy *XTCPProxy) Run() (err error) {
if pxy.cfg.Plugin != "" {
pxy.proxyPlugin, err = plugin.Create(pxy.cfg.Plugin, pxy.cfg.PluginParams)
if err != nil {
return
}
}
return
}
func (pxy *XTCPProxy) Close() {
if pxy.proxyPlugin != nil {
pxy.proxyPlugin.Close()
}
}
func (pxy *XTCPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
xl := pxy.xl
defer conn.Close()
var natHoleSidMsg msg.NatHoleSid
err := msg.ReadMsgInto(conn, &natHoleSidMsg)
if err != nil {
xl.Error("xtcp read from workConn error: %v", err)
return
}
natHoleClientMsg := &msg.NatHoleClient{
ProxyName: pxy.cfg.ProxyName,
Sid: natHoleSidMsg.Sid,
}
raddr, _ := net.ResolveUDPAddr("udp",
fmt.Sprintf("%s:%d", pxy.clientCfg.ServerAddr, pxy.serverUDPPort))
clientConn, err := net.DialUDP("udp", nil, raddr)
if err != nil {
xl.Error("dial server udp addr error: %v", err)
return
}
defer clientConn.Close()
err = msg.WriteMsg(clientConn, natHoleClientMsg)
if err != nil {
xl.Error("send natHoleClientMsg to server error: %v", err)
return
}
// Wait for client address at most 5 seconds.
var natHoleRespMsg msg.NatHoleResp
clientConn.SetReadDeadline(time.Now().Add(5 * time.Second))
buf := pool.GetBuf(1024)
n, err := clientConn.Read(buf)
if err != nil {
xl.Error("get natHoleRespMsg error: %v", err)
return
}
err = msg.ReadMsgInto(bytes.NewReader(buf[:n]), &natHoleRespMsg)
if err != nil {
xl.Error("get natHoleRespMsg error: %v", err)
return
}
clientConn.SetReadDeadline(time.Time{})
clientConn.Close()
if natHoleRespMsg.Error != "" {
xl.Error("natHoleRespMsg get error info: %s", natHoleRespMsg.Error)
return
}
xl.Trace("get natHoleRespMsg, sid [%s], client address [%s] visitor address [%s]", natHoleRespMsg.Sid, natHoleRespMsg.ClientAddr, natHoleRespMsg.VisitorAddr)
// Send detect message
array := strings.Split(natHoleRespMsg.VisitorAddr, ":")
if len(array) <= 1 {
xl.Error("get NatHoleResp visitor address error: %v", natHoleRespMsg.VisitorAddr)
}
laddr, _ := net.ResolveUDPAddr("udp", clientConn.LocalAddr().String())
/*
for i := 1000; i < 65000; i++ {
pxy.sendDetectMsg(array[0], int64(i), laddr, "a")
}
*/
port, err := strconv.ParseInt(array[1], 10, 64)
if err != nil {
xl.Error("get natHoleResp visitor address error: %v", natHoleRespMsg.VisitorAddr)
return
}
pxy.sendDetectMsg(array[0], int(port), laddr, []byte(natHoleRespMsg.Sid))
xl.Trace("send all detect msg done")
msg.WriteMsg(conn, &msg.NatHoleClientDetectOK{})
// Listen for clientConn's address and wait for visitor connection
lConn, err := net.ListenUDP("udp", laddr)
if err != nil {
xl.Error("listen on visitorConn's local adress error: %v", err)
return
}
defer lConn.Close()
lConn.SetReadDeadline(time.Now().Add(8 * time.Second))
sidBuf := pool.GetBuf(1024)
var uAddr *net.UDPAddr
n, uAddr, err = lConn.ReadFromUDP(sidBuf)
if err != nil {
xl.Warn("get sid from visitor error: %v", err)
return
}
lConn.SetReadDeadline(time.Time{})
if string(sidBuf[:n]) != natHoleRespMsg.Sid {
xl.Warn("incorrect sid from visitor")
return
}
pool.PutBuf(sidBuf)
xl.Info("nat hole connection make success, sid [%s]", natHoleRespMsg.Sid)
lConn.WriteToUDP(sidBuf[:n], uAddr)
kcpConn, err := frpNet.NewKCPConnFromUDP(lConn, false, uAddr.String())
if err != nil {
xl.Error("create kcp connection from udp connection error: %v", err)
return
}
fmuxCfg := fmux.DefaultConfig()
fmuxCfg.KeepAliveInterval = 5 * time.Second
fmuxCfg.LogOutput = io.Discard
sess, err := fmux.Server(kcpConn, fmuxCfg)
if err != nil {
xl.Error("create yamux server from kcp connection error: %v", err)
return
}
defer sess.Close()
muxConn, err := sess.Accept()
if err != nil {
xl.Error("accept for yamux connection error: %v", err)
return
}
HandleTCPWorkConnection(pxy.ctx, &pxy.cfg.LocalSvrConf, pxy.proxyPlugin, pxy.cfg.GetBaseInfo(), pxy.limiter,
muxConn, []byte(pxy.cfg.Sk), m)
}
func (pxy *XTCPProxy) sendDetectMsg(addr string, port int, laddr *net.UDPAddr, content []byte) (err error) {
daddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", addr, port))
if err != nil {
return err
}
tConn, err := net.DialUDP("udp", laddr, daddr)
if err != nil {
return err
}
//uConn := ipv4.NewConn(tConn)
//uConn.SetTTL(3)
tConn.Write(content)
tConn.Close()
return nil
}
// UDP
type UDPProxy struct {
*BaseProxy
cfg *config.UDPProxyConf
localAddr *net.UDPAddr
readCh chan *msg.UDPPacket
// include msg.UDPPacket and msg.Ping
sendCh chan msg.Message
workConn net.Conn
}
func (pxy *UDPProxy) Run() (err error) {
pxy.localAddr, err = net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", pxy.cfg.LocalIP, pxy.cfg.LocalPort))
if err != nil {
return
}
return
}
func (pxy *UDPProxy) Close() {
pxy.mu.Lock()
defer pxy.mu.Unlock()
if !pxy.closed {
pxy.closed = true
if pxy.workConn != nil {
pxy.workConn.Close()
}
if pxy.readCh != nil {
close(pxy.readCh)
}
if pxy.sendCh != nil {
close(pxy.sendCh)
}
}
}
func (pxy *UDPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
xl := pxy.xl
xl.Info("incoming a new work connection for udp proxy, %s", conn.RemoteAddr().String())
// close resources releated with old workConn
pxy.Close()
var rwc io.ReadWriteCloser = conn
var err error
if pxy.limiter != nil {
rwc = frpIo.WrapReadWriteCloser(limit.NewReader(conn, pxy.limiter), limit.NewWriter(conn, pxy.limiter), func() error {
return conn.Close()
})
}
if pxy.cfg.UseEncryption {
rwc, err = frpIo.WithEncryption(rwc, []byte(pxy.clientCfg.Token))
if err != nil {
conn.Close()
xl.Error("create encryption stream error: %v", err)
return
}
}
if pxy.cfg.UseCompression {
rwc = frpIo.WithCompression(rwc)
}
conn = frpNet.WrapReadWriteCloserToConn(rwc, conn)
pxy.mu.Lock()
pxy.workConn = conn
pxy.readCh = make(chan *msg.UDPPacket, 1024)
pxy.sendCh = make(chan msg.Message, 1024)
pxy.closed = false
pxy.mu.Unlock()
workConnReaderFn := func(conn net.Conn, readCh chan *msg.UDPPacket) {
for {
var udpMsg msg.UDPPacket
if errRet := msg.ReadMsgInto(conn, &udpMsg); errRet != nil {
xl.Warn("read from workConn for udp error: %v", errRet)
return
}
if errRet := errors.PanicToError(func() {
xl.Trace("get udp package from workConn: %s", udpMsg.Content)
readCh <- &udpMsg
}); errRet != nil {
xl.Info("reader goroutine for udp work connection closed: %v", errRet)
return
}
}
}
workConnSenderFn := func(conn net.Conn, sendCh chan msg.Message) {
defer func() {
xl.Info("writer goroutine for udp work connection closed")
}()
var errRet error
for rawMsg := range sendCh {
switch m := rawMsg.(type) {
case *msg.UDPPacket:
xl.Trace("send udp package to workConn: %s", m.Content)
case *msg.Ping:
xl.Trace("send ping message to udp workConn")
}
if errRet = msg.WriteMsg(conn, rawMsg); errRet != nil {
xl.Error("udp work write error: %v", errRet)
return
}
}
}
heartbeatFn := func(conn net.Conn, sendCh chan msg.Message) {
var errRet error
for {
time.Sleep(time.Duration(30) * time.Second)
if errRet = errors.PanicToError(func() {
sendCh <- &msg.Ping{}
}); errRet != nil {
xl.Trace("heartbeat goroutine for udp work connection closed")
break
}
}
}
go workConnSenderFn(pxy.workConn, pxy.sendCh)
go workConnReaderFn(pxy.workConn, pxy.readCh)
go heartbeatFn(pxy.workConn, pxy.sendCh)
udp.Forwarder(pxy.localAddr, pxy.readCh, pxy.sendCh, int(pxy.clientCfg.UDPPacketSize))
}
type SUDPProxy struct {
*BaseProxy
cfg *config.SUDPProxyConf
localAddr *net.UDPAddr
closeCh chan struct{}
}
func (pxy *SUDPProxy) Run() (err error) {
pxy.localAddr, err = net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", pxy.cfg.LocalIP, pxy.cfg.LocalPort))
if err != nil {
return
}
return
}
func (pxy *SUDPProxy) Close() {
pxy.mu.Lock()
defer pxy.mu.Unlock()
select {
case <-pxy.closeCh:
return
default:
close(pxy.closeCh)
}
}
func (pxy *SUDPProxy) InWorkConn(conn net.Conn, m *msg.StartWorkConn) {
xl := pxy.xl
xl.Info("incoming a new work connection for sudp proxy, %s", conn.RemoteAddr().String())
var rwc io.ReadWriteCloser = conn
var err error
if pxy.limiter != nil {
rwc = frpIo.WrapReadWriteCloser(limit.NewReader(conn, pxy.limiter), limit.NewWriter(conn, pxy.limiter), func() error {
return conn.Close()
})
}
if pxy.cfg.UseEncryption {
rwc, err = frpIo.WithEncryption(rwc, []byte(pxy.clientCfg.Token))
if err != nil {
conn.Close()
xl.Error("create encryption stream error: %v", err)
return
}
}
if pxy.cfg.UseCompression {
rwc = frpIo.WithCompression(rwc)
}
conn = frpNet.WrapReadWriteCloserToConn(rwc, conn)
workConn := conn
readCh := make(chan *msg.UDPPacket, 1024)
sendCh := make(chan msg.Message, 1024)
isClose := false
mu := &sync.Mutex{}
closeFn := func() {
mu.Lock()
defer mu.Unlock()
if isClose {
return
}
isClose = true
if workConn != nil {
workConn.Close()
}
close(readCh)
close(sendCh)
}
// udp service <- frpc <- frps <- frpc visitor <- user
workConnReaderFn := func(conn net.Conn, readCh chan *msg.UDPPacket) {
defer closeFn()
for {
// first to check sudp proxy is closed or not
select {
case <-pxy.closeCh:
xl.Trace("frpc sudp proxy is closed")
return
default:
}
var udpMsg msg.UDPPacket
if errRet := msg.ReadMsgInto(conn, &udpMsg); errRet != nil {
xl.Warn("read from workConn for sudp error: %v", errRet)
return
}
if errRet := errors.PanicToError(func() {
readCh <- &udpMsg
}); errRet != nil {
xl.Warn("reader goroutine for sudp work connection closed: %v", errRet)
return
}
}
}
// udp service -> frpc -> frps -> frpc visitor -> user
workConnSenderFn := func(conn net.Conn, sendCh chan msg.Message) {
defer func() {
closeFn()
xl.Info("writer goroutine for sudp work connection closed")
}()
var errRet error
for rawMsg := range sendCh {
switch m := rawMsg.(type) {
case *msg.UDPPacket:
xl.Trace("frpc send udp package to frpc visitor, [udp local: %v, remote: %v], [tcp work conn local: %v, remote: %v]",
m.LocalAddr.String(), m.RemoteAddr.String(), conn.LocalAddr().String(), conn.RemoteAddr().String())
case *msg.Ping:
xl.Trace("frpc send ping message to frpc visitor")
}
if errRet = msg.WriteMsg(conn, rawMsg); errRet != nil {
xl.Error("sudp work write error: %v", errRet)
return
}
}
}
heartbeatFn := func(conn net.Conn, sendCh chan msg.Message) {
ticker := time.NewTicker(30 * time.Second)
defer func() {
ticker.Stop()
closeFn()
}()
var errRet error
for {
select {
case <-ticker.C:
if errRet = errors.PanicToError(func() {
sendCh <- &msg.Ping{}
}); errRet != nil {
xl.Warn("heartbeat goroutine for sudp work connection closed")
return
}
case <-pxy.closeCh:
xl.Trace("frpc sudp proxy is closed")
return
}
}
}
go workConnSenderFn(workConn, sendCh)
go workConnReaderFn(workConn, readCh)
go heartbeatFn(workConn, sendCh)
udp.Forwarder(pxy.localAddr, readCh, sendCh, int(pxy.clientCfg.UDPPacketSize))
}
// Common handler for tcp work connections.
func HandleTCPWorkConnection(ctx context.Context, localInfo *config.LocalSvrConf, proxyPlugin plugin.Plugin,
baseInfo *config.BaseProxyConf, limiter *rate.Limiter, workConn net.Conn, encKey []byte, m *msg.StartWorkConn) {
xl := xlog.FromContextSafe(ctx)
var (
remote io.ReadWriteCloser
err error
)
remote = workConn
if limiter != nil {
remote = frpIo.WrapReadWriteCloser(limit.NewReader(workConn, limiter), limit.NewWriter(workConn, limiter), func() error {
return workConn.Close()
})
}
xl.Trace("handle tcp work connection, use_encryption: %t, use_compression: %t",
baseInfo.UseEncryption, baseInfo.UseCompression)
if baseInfo.UseEncryption {
remote, err = frpIo.WithEncryption(remote, encKey)
if err != nil {
workConn.Close()
xl.Error("create encryption stream error: %v", err)
return
}
}
if baseInfo.UseCompression {
remote = frpIo.WithCompression(remote)
}
// check if we need to send proxy protocol info
var extraInfo []byte
if baseInfo.ProxyProtocolVersion != "" {
if m.SrcAddr != "" && m.SrcPort != 0 {
if m.DstAddr == "" {
m.DstAddr = "127.0.0.1"
}
srcAddr, _ := net.ResolveTCPAddr("tcp", net.JoinHostPort(m.SrcAddr, strconv.Itoa(int(m.SrcPort))))
dstAddr, _ := net.ResolveTCPAddr("tcp", net.JoinHostPort(m.DstAddr, strconv.Itoa(int(m.DstPort))))
h := &pp.Header{
Command: pp.PROXY,
SourceAddr: srcAddr,
DestinationAddr: dstAddr,
}
if strings.Contains(m.SrcAddr, ".") {
h.TransportProtocol = pp.TCPv4
} else {
h.TransportProtocol = pp.TCPv6
}
if baseInfo.ProxyProtocolVersion == "v1" {
h.Version = 1
} else if baseInfo.ProxyProtocolVersion == "v2" {
h.Version = 2
}
buf := bytes.NewBuffer(nil)
h.WriteTo(buf)
extraInfo = buf.Bytes()
}
}
if proxyPlugin != nil {
// if plugin is set, let plugin handle connections first
xl.Debug("handle by plugin: %s", proxyPlugin.Name())
proxyPlugin.Handle(remote, workConn, extraInfo)
xl.Debug("handle by plugin finished")
return
}
localConn, err := frpNet.ConnectServer("tcp", fmt.Sprintf("%s:%d", localInfo.LocalIP, localInfo.LocalPort))
if err != nil {
workConn.Close()
xl.Error("connect to local service [%s:%d] error: %v", localInfo.LocalIP, localInfo.LocalPort, err)
return
}
xl.Debug("join connections, localConn(l[%s] r[%s]) workConn(l[%s] r[%s])", localConn.LocalAddr().String(),
localConn.RemoteAddr().String(), workConn.LocalAddr().String(), workConn.RemoteAddr().String())
if len(extraInfo) > 0 {
localConn.Write(extraInfo)
}
frpIo.Join(localConn, remote)
xl.Debug("join connections closed")
}