start refactoring

utils/net/udp.go

@@ -0,0 +1,243 @@
+// 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 net
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"sync"
+	"time"
+
+	flog "github.com/fatedier/frp/utils/log"
+	"github.com/fatedier/frp/utils/pool"
+)
+
+type UdpPacket struct {
+	Buf        []byte
+	LocalAddr  net.Addr
+	RemoteAddr net.Addr
+}
+
+type FakeUdpConn struct {
+	flog.Logger
+	l *UdpListener
+
+	localAddr  net.Addr
+	remoteAddr net.Addr
+	packets    chan []byte
+	closeFlag  bool
+
+	lastActive time.Time
+	mu         sync.RWMutex
+}
+
+func NewFakeUdpConn(l *UdpListener, laddr, raddr net.Addr) *FakeUdpConn {
+	fc := &FakeUdpConn{
+		Logger:     flog.NewPrefixLogger(""),
+		l:          l,
+		localAddr:  laddr,
+		remoteAddr: raddr,
+		packets:    make(chan []byte, 20),
+	}
+
+	go func() {
+		for {
+			time.Sleep(5 * time.Second)
+			fc.mu.RLock()
+			if time.Now().Sub(fc.lastActive) > 10*time.Second {
+				fc.mu.RUnlock()
+				fc.Close()
+				break
+			}
+			fc.mu.RUnlock()
+		}
+	}()
+	return fc
+}
+
+func (c *FakeUdpConn) putPacket(content []byte) {
+	defer func() {
+		if err := recover(); err != nil {
+		}
+	}()
+
+	select {
+	case c.packets <- content:
+	default:
+	}
+}
+
+func (c *FakeUdpConn) Read(b []byte) (n int, err error) {
+	content, ok := <-c.packets
+	if !ok {
+		return 0, io.EOF
+	}
+	c.mu.Lock()
+	c.lastActive = time.Now()
+	c.mu.Unlock()
+
+	if len(b) < len(content) {
+		n = len(b)
+	} else {
+		n = len(content)
+	}
+	copy(b, content)
+	return n, nil
+}
+
+func (c *FakeUdpConn) Write(b []byte) (n int, err error) {
+	c.mu.RLock()
+	if c.closeFlag {
+		c.mu.RUnlock()
+		return 0, io.ErrClosedPipe
+	}
+	c.mu.RUnlock()
+
+	packet := &UdpPacket{
+		Buf:        b,
+		LocalAddr:  c.localAddr,
+		RemoteAddr: c.remoteAddr,
+	}
+	c.l.writeUdpPacket(packet)
+
+	c.mu.Lock()
+	c.lastActive = time.Now()
+	c.mu.Unlock()
+	return len(b), nil
+}
+
+func (c *FakeUdpConn) Close() error {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if !c.closeFlag {
+		c.closeFlag = true
+		close(c.packets)
+	}
+	return nil
+}
+
+func (c *FakeUdpConn) IsClosed() bool {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.closeFlag
+}
+
+func (c *FakeUdpConn) LocalAddr() net.Addr {
+	return c.localAddr
+}
+
+func (c *FakeUdpConn) RemoteAddr() net.Addr {
+	return c.remoteAddr
+}
+
+func (c *FakeUdpConn) SetDeadline(t time.Time) error {
+	return nil
+}
+
+func (c *FakeUdpConn) SetReadDeadline(t time.Time) error {
+	return nil
+}
+
+func (c *FakeUdpConn) SetWriteDeadline(t time.Time) error {
+	return nil
+}
+
+type UdpListener struct {
+	net.Addr
+	accept    chan Conn
+	writeCh   chan *UdpPacket
+	readConn  net.Conn
+	closeFlag bool
+
+	fakeConns map[string]*FakeUdpConn
+}
+
+func ListenUDP(bindAddr string, bindPort int64) (l *UdpListener, err error) {
+	udpAddr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", bindAddr, bindPort))
+	if err != nil {
+		return l, err
+	}
+	readConn, err := net.ListenUDP("udp", udpAddr)
+
+	l = &UdpListener{
+		Addr:      udpAddr,
+		accept:    make(chan Conn),
+		writeCh:   make(chan *UdpPacket, 1000),
+		fakeConns: make(map[string]*FakeUdpConn),
+	}
+
+	// for reading
+	go func() {
+		for {
+			buf := pool.GetBuf(1450)
+			n, remoteAddr, err := readConn.ReadFromUDP(buf)
+			if err != nil {
+				close(l.accept)
+				close(l.writeCh)
+				return
+			}
+
+			fakeConn, exist := l.fakeConns[remoteAddr.String()]
+			if !exist || fakeConn.IsClosed() {
+				fakeConn = NewFakeUdpConn(l, l.Addr, remoteAddr)
+				l.fakeConns[remoteAddr.String()] = fakeConn
+			}
+			fakeConn.putPacket(buf[:n])
+
+			l.accept <- fakeConn
+		}
+	}()
+
+	// for writing
+	go func() {
+		for {
+			packet, ok := <-l.writeCh
+			if !ok {
+				return
+			}
+
+			if addr, ok := packet.RemoteAddr.(*net.UDPAddr); ok {
+				readConn.WriteToUDP(packet.Buf, addr)
+			}
+		}
+	}()
+
+	return
+}
+
+func (l *UdpListener) writeUdpPacket(packet *UdpPacket) {
+	defer func() {
+		if err := recover(); err != nil {
+		}
+	}()
+	l.writeCh <- packet
+}
+
+func (l *UdpListener) Accept() (Conn, error) {
+	conn, ok := <-l.accept
+	if !ok {
+		return conn, fmt.Errorf("channel for udp listener closed")
+	}
+	return conn, nil
+}
+
+func (l *UdpListener) Close() error {
+	if !l.closeFlag {
+		l.closeFlag = true
+		l.readConn.Close()
+	}
+	return nil
+}