126 lines
2.8 KiB
Go
126 lines
2.8 KiB
Go
package main
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import (
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"encoding/json"
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"fmt"
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"io"
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"io/ioutil"
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"net"
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"os"
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"strings"
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)
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type TcpListen struct {
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Listen string `json:"listen"`
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Backend string `json:"backend"`
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}
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type TcpListenConfig struct {
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TcpListens []TcpListen `json:"tcpListens"`
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}
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// {
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// "tcpListens": [
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// {
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// "listen": ":8080",
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// "backend": "11.22.33.44:8080"
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// }
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// ]
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// }
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// https://blog.csdn.net/fyxichen/article/details/51505542
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func main() {
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tcpListenConfig, err := readConfigFile()
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if err != nil {
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fmt.Printf("[ERROR] Error in load config file: %v\n", err)
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return
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}
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if len(tcpListenConfig.TcpListens) == 0 {
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fmt.Println("[ERROR] Not find any mapping in config")
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return
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}
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for _, tcpListen := range tcpListenConfig.TcpListens {
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go serverTcpListen(tcpListen)
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}
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ExitChan := make(chan bool, 1)
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<-ExitChan
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}
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func serverTcpListen(tcpListen TcpListen) {
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lis, err := net.Listen("tcp", tcpListen.Listen)
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if err != nil {
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fmt.Println(err)
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return
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}
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defer lis.Close()
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fmt.Printf("[INFO] Listen TCP at: %v --> %v\n", tcpListen.Listen, tcpListen.Backend)
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for {
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conn, err := lis.Accept()
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if err != nil {
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fmt.Printf("[ERROR] Listen error: %v\n", err)
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continue
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}
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fmt.Printf("[INFO] TCP connection from %v, local: %v\n", conn.RemoteAddr(), conn.LocalAddr())
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go handleTcpRequest(tcpListen, conn)
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}
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}
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func handleTcpRequest(tcpListen TcpListen, sconn net.Conn) {
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defer sconn.Close()
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ip := tcpListen.Backend
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dconn, err := net.Dial("tcp", ip)
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if err != nil {
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fmt.Printf("[ERROR] Connect to %v failed:%v\n", ip, err)
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return
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}
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ExitChan := make(chan bool, 1)
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go func(sconn net.Conn, dconn net.Conn, Exit chan bool) {
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_, err := io.Copy(dconn, sconn)
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if err != nil {
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errStr := fmt.Sprintf("%v", err)
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if strings.Contains(errStr, "use of closed network connection") {
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fmt.Printf("[INFO] Connection closed: %v\n", ip)
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} else {
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fmt.Printf("[WARN] Send data to %v failed:%v\n", ip, err)
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}
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}
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Exit <- true
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}(sconn, dconn, ExitChan)
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go func(sconn net.Conn, dconn net.Conn, Exit chan bool) {
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_, err := io.Copy(sconn, dconn)
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if err != nil {
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errStr := fmt.Sprintf("%v", err)
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if strings.Contains(errStr, "use of closed network connection") {
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fmt.Printf("[INFO] Connection closed: %v\n", ip)
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} else {
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fmt.Printf("[WARN] Receive data from %v failed:%v\n", ip, err)
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}
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}
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Exit <- true
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}(sconn, dconn, ExitChan)
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<-ExitChan
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dconn.Close()
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}
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func readConfigFile() (*TcpListenConfig, error) {
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configFile, err := os.Open("tcp_listen_config.json")
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if err != nil {
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return nil, err
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}
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defer configFile.Close()
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configFileBytes, err := ioutil.ReadAll(configFile)
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if err != nil {
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return nil, err
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}
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var tcpListenConfig TcpListenConfig
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err = json.Unmarshal(configFileBytes, &tcpListenConfig)
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if err != nil {
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return nil, err
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}
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return &tcpListenConfig, nil
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}
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