frp/server/proxy/udp.go

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// Copyright 2019 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 (
"context"
"fmt"
"net"
"time"
"github.com/fatedier/frp/models/config"
"github.com/fatedier/frp/models/msg"
"github.com/fatedier/frp/models/proto/udp"
"github.com/fatedier/frp/server/stats"
"github.com/fatedier/golib/errors"
)
type UdpProxy struct {
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*BaseProxy
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cfg *config.UdpProxyConf
realPort int
// udpConn is the listener of udp packages
udpConn *net.UDPConn
// there are always only one workConn at the same time
// get another one if it closed
workConn net.Conn
// sendCh is used for sending packages to workConn
sendCh chan *msg.UdpPacket
// readCh is used for reading packages from workConn
readCh chan *msg.UdpPacket
// checkCloseCh is used for watching if workConn is closed
checkCloseCh chan int
isClosed bool
}
func (pxy *UdpProxy) Run() (remoteAddr string, err error) {
pxy.realPort, err = pxy.rc.UdpPortManager.Acquire(pxy.name, pxy.cfg.RemotePort)
if err != nil {
return
}
defer func() {
if err != nil {
pxy.rc.UdpPortManager.Release(pxy.realPort)
}
}()
remoteAddr = fmt.Sprintf(":%d", pxy.realPort)
pxy.cfg.RemotePort = pxy.realPort
addr, errRet := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", pxy.serverCfg.ProxyBindAddr, pxy.realPort))
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if errRet != nil {
err = errRet
return
}
udpConn, errRet := net.ListenUDP("udp", addr)
if errRet != nil {
err = errRet
pxy.Warn("listen udp port error: %v", err)
return
}
pxy.Info("udp proxy listen port [%d]", pxy.cfg.RemotePort)
pxy.udpConn = udpConn
pxy.sendCh = make(chan *msg.UdpPacket, 1024)
pxy.readCh = make(chan *msg.UdpPacket, 1024)
pxy.checkCloseCh = make(chan int)
// read message from workConn, if it returns any error, notify proxy to start a new workConn
workConnReaderFn := func(conn net.Conn) {
for {
var (
rawMsg msg.Message
errRet error
)
pxy.Trace("loop waiting message from udp workConn")
// client will send heartbeat in workConn for keeping alive
conn.SetReadDeadline(time.Now().Add(time.Duration(60) * time.Second))
if rawMsg, errRet = msg.ReadMsg(conn); errRet != nil {
pxy.Warn("read from workConn for udp error: %v", errRet)
conn.Close()
// notify proxy to start a new work connection
// ignore error here, it means the proxy is closed
errors.PanicToError(func() {
pxy.checkCloseCh <- 1
})
return
}
conn.SetReadDeadline(time.Time{})
switch m := rawMsg.(type) {
case *msg.Ping:
pxy.Trace("udp work conn get ping message")
continue
case *msg.UdpPacket:
if errRet := errors.PanicToError(func() {
pxy.Trace("get udp message from workConn: %s", m.Content)
pxy.readCh <- m
pxy.statsCollector.Mark(stats.TypeAddTrafficOut, &stats.AddTrafficOutPayload{
ProxyName: pxy.GetName(),
TrafficBytes: int64(len(m.Content)),
})
}); errRet != nil {
conn.Close()
pxy.Info("reader goroutine for udp work connection closed")
return
}
}
}
}
// send message to workConn
workConnSenderFn := func(conn net.Conn, ctx context.Context) {
var errRet error
for {
select {
case udpMsg, ok := <-pxy.sendCh:
if !ok {
pxy.Info("sender goroutine for udp work connection closed")
return
}
if errRet = msg.WriteMsg(conn, udpMsg); errRet != nil {
pxy.Info("sender goroutine for udp work connection closed: %v", errRet)
conn.Close()
return
} else {
pxy.Trace("send message to udp workConn: %s", udpMsg.Content)
pxy.statsCollector.Mark(stats.TypeAddTrafficIn, &stats.AddTrafficInPayload{
ProxyName: pxy.GetName(),
TrafficBytes: int64(len(udpMsg.Content)),
})
continue
}
case <-ctx.Done():
pxy.Info("sender goroutine for udp work connection closed")
return
}
}
}
go func() {
// Sleep a while for waiting control send the NewProxyResp to client.
time.Sleep(500 * time.Millisecond)
for {
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workConn, err := pxy.GetWorkConnFromPool(nil, nil)
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if err != nil {
time.Sleep(1 * time.Second)
// check if proxy is closed
select {
case _, ok := <-pxy.checkCloseCh:
if !ok {
return
}
default:
}
continue
}
// close the old workConn and replac it with a new one
if pxy.workConn != nil {
pxy.workConn.Close()
}
pxy.workConn = workConn
ctx, cancel := context.WithCancel(context.Background())
go workConnReaderFn(workConn)
go workConnSenderFn(workConn, ctx)
_, ok := <-pxy.checkCloseCh
cancel()
if !ok {
return
}
}
}()
// Read from user connections and send wrapped udp message to sendCh (forwarded by workConn).
// Client will transfor udp message to local udp service and waiting for response for a while.
// Response will be wrapped to be forwarded by work connection to server.
// Close readCh and sendCh at the end.
go func() {
udp.ForwardUserConn(udpConn, pxy.readCh, pxy.sendCh)
pxy.Close()
}()
return remoteAddr, nil
}
func (pxy *UdpProxy) GetConf() config.ProxyConf {
return pxy.cfg
}
func (pxy *UdpProxy) Close() {
pxy.mu.Lock()
defer pxy.mu.Unlock()
if !pxy.isClosed {
pxy.isClosed = true
pxy.BaseProxy.Close()
if pxy.workConn != nil {
pxy.workConn.Close()
}
pxy.udpConn.Close()
// all channels only closed here
close(pxy.checkCloseCh)
close(pxy.readCh)
close(pxy.sendCh)
}
pxy.rc.UdpPortManager.Release(pxy.realPort)
}