mirror of https://github.com/fatedier/frp.git
458 lines
12 KiB
Go
458 lines
12 KiB
Go
// Copyright 2017 fatedier, fatedier@gmail.com
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package visitor
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net"
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"strconv"
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"sync"
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"time"
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libio "github.com/fatedier/golib/io"
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fmux "github.com/hashicorp/yamux"
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quic "github.com/quic-go/quic-go"
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"golang.org/x/time/rate"
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v1 "github.com/fatedier/frp/pkg/config/v1"
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"github.com/fatedier/frp/pkg/msg"
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"github.com/fatedier/frp/pkg/nathole"
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"github.com/fatedier/frp/pkg/transport"
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netpkg "github.com/fatedier/frp/pkg/util/net"
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"github.com/fatedier/frp/pkg/util/util"
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"github.com/fatedier/frp/pkg/util/xlog"
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)
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var ErrNoTunnelSession = errors.New("no tunnel session")
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type XTCPVisitor struct {
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*BaseVisitor
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session TunnelSession
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startTunnelCh chan struct{}
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retryLimiter *rate.Limiter
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cancel context.CancelFunc
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cfg *v1.XTCPVisitorConfig
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}
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func (sv *XTCPVisitor) Run() (err error) {
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sv.ctx, sv.cancel = context.WithCancel(sv.ctx)
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if sv.cfg.Protocol == "kcp" {
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sv.session = NewKCPTunnelSession()
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} else {
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sv.session = NewQUICTunnelSession(sv.clientCfg)
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}
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if sv.cfg.BindPort > 0 {
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sv.l, err = net.Listen("tcp", net.JoinHostPort(sv.cfg.BindAddr, strconv.Itoa(sv.cfg.BindPort)))
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if err != nil {
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return
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}
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go sv.worker()
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}
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go sv.internalConnWorker()
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go sv.processTunnelStartEvents()
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if sv.cfg.KeepTunnelOpen {
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sv.retryLimiter = rate.NewLimiter(rate.Every(time.Hour/time.Duration(sv.cfg.MaxRetriesAnHour)), sv.cfg.MaxRetriesAnHour)
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go sv.keepTunnelOpenWorker()
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}
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return
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}
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func (sv *XTCPVisitor) Close() {
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sv.mu.Lock()
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defer sv.mu.Unlock()
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sv.BaseVisitor.Close()
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if sv.cancel != nil {
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sv.cancel()
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}
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if sv.session != nil {
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sv.session.Close()
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}
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}
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func (sv *XTCPVisitor) worker() {
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xl := xlog.FromContextSafe(sv.ctx)
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for {
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conn, err := sv.l.Accept()
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if err != nil {
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xl.Warnf("xtcp local listener closed")
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return
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}
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go sv.handleConn(conn)
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}
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}
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func (sv *XTCPVisitor) internalConnWorker() {
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xl := xlog.FromContextSafe(sv.ctx)
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for {
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conn, err := sv.internalLn.Accept()
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if err != nil {
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xl.Warnf("xtcp internal listener closed")
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return
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}
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go sv.handleConn(conn)
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}
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}
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func (sv *XTCPVisitor) processTunnelStartEvents() {
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for {
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select {
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case <-sv.ctx.Done():
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return
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case <-sv.startTunnelCh:
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start := time.Now()
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sv.makeNatHole()
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duration := time.Since(start)
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// avoid too frequently
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if duration < 10*time.Second {
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time.Sleep(10*time.Second - duration)
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}
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}
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}
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}
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func (sv *XTCPVisitor) keepTunnelOpenWorker() {
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xl := xlog.FromContextSafe(sv.ctx)
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ticker := time.NewTicker(time.Duration(sv.cfg.MinRetryInterval) * time.Second)
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defer ticker.Stop()
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sv.startTunnelCh <- struct{}{}
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for {
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select {
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case <-sv.ctx.Done():
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return
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case <-ticker.C:
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xl.Debugf("keepTunnelOpenWorker try to check tunnel...")
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conn, err := sv.getTunnelConn()
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if err != nil {
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xl.Warnf("keepTunnelOpenWorker get tunnel connection error: %v", err)
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_ = sv.retryLimiter.Wait(sv.ctx)
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continue
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}
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xl.Debugf("keepTunnelOpenWorker check success")
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if conn != nil {
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conn.Close()
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}
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}
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}
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}
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func (sv *XTCPVisitor) handleConn(userConn net.Conn) {
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xl := xlog.FromContextSafe(sv.ctx)
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isConnTrasfered := false
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defer func() {
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if !isConnTrasfered {
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userConn.Close()
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}
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}()
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xl.Debugf("get a new xtcp user connection")
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// Open a tunnel connection to the server. If there is already a successful hole-punching connection,
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// it will be reused. Otherwise, it will block and wait for a successful hole-punching connection until timeout.
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ctx := context.Background()
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if sv.cfg.FallbackTo != "" {
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timeoutCtx, cancel := context.WithTimeout(ctx, time.Duration(sv.cfg.FallbackTimeoutMs)*time.Millisecond)
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defer cancel()
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ctx = timeoutCtx
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}
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tunnelConn, err := sv.openTunnel(ctx)
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if err != nil {
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xl.Errorf("open tunnel error: %v", err)
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// no fallback, just return
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if sv.cfg.FallbackTo == "" {
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return
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}
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xl.Debugf("try to transfer connection to visitor: %s", sv.cfg.FallbackTo)
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if err := sv.helper.TransferConn(sv.cfg.FallbackTo, userConn); err != nil {
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xl.Errorf("transfer connection to visitor %s error: %v", sv.cfg.FallbackTo, err)
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return
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}
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isConnTrasfered = true
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return
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}
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var muxConnRWCloser io.ReadWriteCloser = tunnelConn
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if sv.cfg.Transport.UseEncryption {
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muxConnRWCloser, err = libio.WithEncryption(muxConnRWCloser, []byte(sv.cfg.SecretKey))
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if err != nil {
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xl.Errorf("create encryption stream error: %v", err)
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return
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}
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}
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if sv.cfg.Transport.UseCompression {
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var recycleFn func()
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muxConnRWCloser, recycleFn = libio.WithCompressionFromPool(muxConnRWCloser)
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defer recycleFn()
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}
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_, _, errs := libio.Join(userConn, muxConnRWCloser)
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xl.Debugf("join connections closed")
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if len(errs) > 0 {
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xl.Tracef("join connections errors: %v", errs)
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}
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}
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// openTunnel will open a tunnel connection to the target server.
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func (sv *XTCPVisitor) openTunnel(ctx context.Context) (conn net.Conn, err error) {
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xl := xlog.FromContextSafe(sv.ctx)
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ticker := time.NewTicker(500 * time.Millisecond)
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defer ticker.Stop()
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timeoutC := time.After(20 * time.Second)
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immediateTrigger := make(chan struct{}, 1)
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defer close(immediateTrigger)
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immediateTrigger <- struct{}{}
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for {
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select {
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case <-sv.ctx.Done():
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return nil, sv.ctx.Err()
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case <-ctx.Done():
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return nil, ctx.Err()
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case <-immediateTrigger:
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conn, err = sv.getTunnelConn()
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case <-ticker.C:
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conn, err = sv.getTunnelConn()
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case <-timeoutC:
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return nil, fmt.Errorf("open tunnel timeout")
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}
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if err != nil {
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if err != ErrNoTunnelSession {
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xl.Warnf("get tunnel connection error: %v", err)
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}
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continue
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}
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return conn, nil
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}
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}
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func (sv *XTCPVisitor) getTunnelConn() (net.Conn, error) {
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conn, err := sv.session.OpenConn(sv.ctx)
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if err == nil {
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return conn, nil
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}
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sv.session.Close()
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select {
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case sv.startTunnelCh <- struct{}{}:
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default:
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}
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return nil, err
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}
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// 0. PreCheck
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// 1. Prepare
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// 2. ExchangeInfo
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// 3. MakeNATHole
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// 4. Create a tunnel session using an underlying UDP connection.
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func (sv *XTCPVisitor) makeNatHole() {
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xl := xlog.FromContextSafe(sv.ctx)
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xl.Tracef("makeNatHole start")
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if err := nathole.PreCheck(sv.ctx, sv.helper.MsgTransporter(), sv.cfg.ServerName, 5*time.Second); err != nil {
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xl.Warnf("nathole precheck error: %v", err)
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return
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}
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xl.Tracef("nathole prepare start")
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prepareResult, err := nathole.Prepare([]string{sv.clientCfg.NatHoleSTUNServer})
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if err != nil {
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xl.Warnf("nathole prepare error: %v", err)
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return
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}
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xl.Infof("nathole prepare success, nat type: %s, behavior: %s, addresses: %v, assistedAddresses: %v",
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prepareResult.NatType, prepareResult.Behavior, prepareResult.Addrs, prepareResult.AssistedAddrs)
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listenConn := prepareResult.ListenConn
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// send NatHoleVisitor to server
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now := time.Now().Unix()
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transactionID := nathole.NewTransactionID()
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natHoleVisitorMsg := &msg.NatHoleVisitor{
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TransactionID: transactionID,
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ProxyName: sv.cfg.ServerName,
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Protocol: sv.cfg.Protocol,
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SignKey: util.GetAuthKey(sv.cfg.SecretKey, now),
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Timestamp: now,
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MappedAddrs: prepareResult.Addrs,
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AssistedAddrs: prepareResult.AssistedAddrs,
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}
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xl.Tracef("nathole exchange info start")
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natHoleRespMsg, err := nathole.ExchangeInfo(sv.ctx, sv.helper.MsgTransporter(), transactionID, natHoleVisitorMsg, 5*time.Second)
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if err != nil {
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listenConn.Close()
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xl.Warnf("nathole exchange info error: %v", err)
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return
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}
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xl.Infof("get natHoleRespMsg, sid [%s], protocol [%s], candidate address %v, assisted address %v, detectBehavior: %+v",
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natHoleRespMsg.Sid, natHoleRespMsg.Protocol, natHoleRespMsg.CandidateAddrs,
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natHoleRespMsg.AssistedAddrs, natHoleRespMsg.DetectBehavior)
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newListenConn, raddr, err := nathole.MakeHole(sv.ctx, listenConn, natHoleRespMsg, []byte(sv.cfg.SecretKey))
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if err != nil {
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listenConn.Close()
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xl.Warnf("make hole error: %v", err)
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return
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}
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listenConn = newListenConn
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xl.Infof("establishing nat hole connection successful, sid [%s], remoteAddr [%s]", natHoleRespMsg.Sid, raddr)
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if err := sv.session.Init(listenConn, raddr); err != nil {
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listenConn.Close()
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xl.Warnf("init tunnel session error: %v", err)
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return
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}
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}
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type TunnelSession interface {
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Init(listenConn *net.UDPConn, raddr *net.UDPAddr) error
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OpenConn(context.Context) (net.Conn, error)
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Close()
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}
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type KCPTunnelSession struct {
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session *fmux.Session
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lConn *net.UDPConn
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mu sync.RWMutex
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}
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func NewKCPTunnelSession() TunnelSession {
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return &KCPTunnelSession{}
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}
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func (ks *KCPTunnelSession) Init(listenConn *net.UDPConn, raddr *net.UDPAddr) error {
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listenConn.Close()
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laddr, _ := net.ResolveUDPAddr("udp", listenConn.LocalAddr().String())
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lConn, err := net.DialUDP("udp", laddr, raddr)
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if err != nil {
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return fmt.Errorf("dial udp error: %v", err)
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}
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remote, err := netpkg.NewKCPConnFromUDP(lConn, true, raddr.String())
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if err != nil {
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return fmt.Errorf("create kcp connection from udp connection error: %v", err)
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}
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fmuxCfg := fmux.DefaultConfig()
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fmuxCfg.KeepAliveInterval = 10 * time.Second
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fmuxCfg.MaxStreamWindowSize = 6 * 1024 * 1024
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fmuxCfg.LogOutput = io.Discard
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session, err := fmux.Client(remote, fmuxCfg)
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if err != nil {
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remote.Close()
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return fmt.Errorf("initial client session error: %v", err)
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}
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ks.mu.Lock()
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ks.session = session
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ks.lConn = lConn
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ks.mu.Unlock()
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return nil
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}
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func (ks *KCPTunnelSession) OpenConn(_ context.Context) (net.Conn, error) {
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ks.mu.RLock()
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defer ks.mu.RUnlock()
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session := ks.session
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if session == nil {
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return nil, ErrNoTunnelSession
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}
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return session.Open()
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}
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func (ks *KCPTunnelSession) Close() {
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ks.mu.Lock()
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defer ks.mu.Unlock()
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if ks.session != nil {
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_ = ks.session.Close()
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ks.session = nil
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}
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if ks.lConn != nil {
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_ = ks.lConn.Close()
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ks.lConn = nil
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}
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}
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type QUICTunnelSession struct {
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session quic.Connection
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listenConn *net.UDPConn
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mu sync.RWMutex
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clientCfg *v1.ClientCommonConfig
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}
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func NewQUICTunnelSession(clientCfg *v1.ClientCommonConfig) TunnelSession {
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return &QUICTunnelSession{
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clientCfg: clientCfg,
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}
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}
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func (qs *QUICTunnelSession) Init(listenConn *net.UDPConn, raddr *net.UDPAddr) error {
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tlsConfig, err := transport.NewClientTLSConfig("", "", "", raddr.String())
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if err != nil {
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return fmt.Errorf("create tls config error: %v", err)
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}
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tlsConfig.NextProtos = []string{"frp"}
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quicConn, err := quic.Dial(context.Background(), listenConn, raddr, tlsConfig,
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&quic.Config{
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MaxIdleTimeout: time.Duration(qs.clientCfg.Transport.QUIC.MaxIdleTimeout) * time.Second,
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MaxIncomingStreams: int64(qs.clientCfg.Transport.QUIC.MaxIncomingStreams),
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KeepAlivePeriod: time.Duration(qs.clientCfg.Transport.QUIC.KeepalivePeriod) * time.Second,
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})
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if err != nil {
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return fmt.Errorf("dial quic error: %v", err)
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}
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qs.mu.Lock()
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qs.session = quicConn
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qs.listenConn = listenConn
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qs.mu.Unlock()
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return nil
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}
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func (qs *QUICTunnelSession) OpenConn(ctx context.Context) (net.Conn, error) {
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qs.mu.RLock()
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defer qs.mu.RUnlock()
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session := qs.session
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if session == nil {
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return nil, ErrNoTunnelSession
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}
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stream, err := session.OpenStreamSync(ctx)
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if err != nil {
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return nil, err
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}
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return netpkg.QuicStreamToNetConn(stream, session), nil
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}
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func (qs *QUICTunnelSession) Close() {
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qs.mu.Lock()
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defer qs.mu.Unlock()
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if qs.session != nil {
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_ = qs.session.CloseWithError(0, "")
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qs.session = nil
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}
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if qs.listenConn != nil {
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_ = qs.listenConn.Close()
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qs.listenConn = nil
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}
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}
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