refactor the code related to xtcp (#3449)

client/proxy/udp.go

@@ -0,0 +1,157 @@
+// Copyright 2023 The frp Authors
+//
+// 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 (
+	"io"
+	"net"
+	"strconv"
+	"time"
+
+	"github.com/fatedier/golib/errors"
+	frpIo "github.com/fatedier/golib/io"
+
+	"github.com/fatedier/frp/pkg/config"
+	"github.com/fatedier/frp/pkg/msg"
+	"github.com/fatedier/frp/pkg/proto/udp"
+	"github.com/fatedier/frp/pkg/util/limit"
+	frpNet "github.com/fatedier/frp/pkg/util/net"
+)
+
+// 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", net.JoinHostPort(pxy.cfg.LocalIP, strconv.Itoa(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(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.sendCh)
+	udp.Forwarder(pxy.localAddr, pxy.readCh, pxy.sendCh, int(pxy.clientCfg.UDPPacketSize))
+}