rename models to pkg (#2005)

pkg/proto/udp/udp.go

@@ -0,0 +1,137 @@
+// 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 udp
+
+import (
+	"encoding/base64"
+	"net"
+	"sync"
+	"time"
+
+	"github.com/fatedier/frp/pkg/msg"
+
+	"github.com/fatedier/golib/errors"
+	"github.com/fatedier/golib/pool"
+)
+
+func NewUDPPacket(buf []byte, laddr, raddr *net.UDPAddr) *msg.UDPPacket {
+	return &msg.UDPPacket{
+		Content:    base64.StdEncoding.EncodeToString(buf),
+		LocalAddr:  laddr,
+		RemoteAddr: raddr,
+	}
+}
+
+func GetContent(m *msg.UDPPacket) (buf []byte, err error) {
+	buf, err = base64.StdEncoding.DecodeString(m.Content)
+	return
+}
+
+func ForwardUserConn(udpConn *net.UDPConn, readCh <-chan *msg.UDPPacket, sendCh chan<- *msg.UDPPacket, bufSize int) {
+	// read
+	go func() {
+		for udpMsg := range readCh {
+			buf, err := GetContent(udpMsg)
+			if err != nil {
+				continue
+			}
+			udpConn.WriteToUDP(buf, udpMsg.RemoteAddr)
+		}
+	}()
+
+	// write
+	buf := pool.GetBuf(bufSize)
+	defer pool.PutBuf(buf)
+	for {
+		n, remoteAddr, err := udpConn.ReadFromUDP(buf)
+		if err != nil {
+			return
+		}
+		// buf[:n] will be encoded to string, so the bytes can be reused
+		udpMsg := NewUDPPacket(buf[:n], nil, remoteAddr)
+
+		select {
+		case sendCh <- udpMsg:
+		default:
+		}
+	}
+}
+
+func Forwarder(dstAddr *net.UDPAddr, readCh <-chan *msg.UDPPacket, sendCh chan<- msg.Message, bufSize int) {
+	var (
+		mu sync.RWMutex
+	)
+	udpConnMap := make(map[string]*net.UDPConn)
+
+	// read from dstAddr and write to sendCh
+	writerFn := func(raddr *net.UDPAddr, udpConn *net.UDPConn) {
+		addr := raddr.String()
+		defer func() {
+			mu.Lock()
+			delete(udpConnMap, addr)
+			mu.Unlock()
+			udpConn.Close()
+		}()
+
+		buf := pool.GetBuf(bufSize)
+		for {
+			udpConn.SetReadDeadline(time.Now().Add(30 * time.Second))
+			n, _, err := udpConn.ReadFromUDP(buf)
+			if err != nil {
+				return
+			}
+
+			udpMsg := NewUDPPacket(buf[:n], nil, raddr)
+			if err = errors.PanicToError(func() {
+				select {
+				case sendCh <- udpMsg:
+				default:
+				}
+			}); err != nil {
+				return
+			}
+		}
+	}
+
+	// read from readCh
+	go func() {
+		for udpMsg := range readCh {
+			buf, err := GetContent(udpMsg)
+			if err != nil {
+				continue
+			}
+			mu.Lock()
+			udpConn, ok := udpConnMap[udpMsg.RemoteAddr.String()]
+			if !ok {
+				udpConn, err = net.DialUDP("udp", nil, dstAddr)
+				if err != nil {
+					mu.Unlock()
+					continue
+				}
+				udpConnMap[udpMsg.RemoteAddr.String()] = udpConn
+			}
+			mu.Unlock()
+
+			_, err = udpConn.Write(buf)
+			if err != nil {
+				udpConn.Close()
+			}
+
+			if !ok {
+				go writerFn(udpMsg.RemoteAddr, udpConn)
+			}
+		}
+	}()
+}