TCP端口转发与映射核心代码：
本文章代码已用于生产环境，用来实现简单的负载均衡
github:https://github.com/lishuangquan1987/tcp_map
package main
import (
"encoding/json"
"fmt"
"io/ioutil"
"log"
"math/rand"
"net"
"os"
"time"
)
type EndpointInfo struct {
Ipstr string `json:"ipstr"`
}
type Config struct {
Host EndpointInfo `json:"host"`
MapList []EndpointInfo `json:"maplist"`
}
var config Config
func init() {
f, err := os.Open("tcp_map.json")
if err != nil {
panic(err)
}
defer f.Close()
bytes, err := ioutil.ReadAll(f)
if err != nil {
panic(err)
}
err = json.Unmarshal(bytes, &config)
if err != nil {
panic(err)
}
//设置随机数种子
rand.Seed(time.Now().UnixNano())
}
func main() {
fmt.Println("welcome to tony tcp map!")
fromaddr := config.Host.Ipstr
fromlistener, err := net.Listen("tcp", fromaddr)
if err != nil {
log.Fatalf("Unable to listen on: %s, error: %sn", fromaddr, err.Error())
}
defer fromlistener.Close()
tcpMap(fromlistener)
}
func tcpMap(listener net.Listener) {
for {
con, err := listener.Accept()
if err != nil {
panic(err)
}
//使用算法随机选取一个
toIpStr := RandomSelect(config.MapList).Ipstr
go func() {
toCon, err := net.Dial("tcp", toIpStr)
if err != nil {
fmt.Printf("can not connect to %s", toIpStr)
return
}
go handleConnection(con, toCon)
go handleConnection(toCon, con)
}()
}
}
func RandomSelect(endPoints []EndpointInfo) EndpointInfo {
index := rand.Intn(len(endPoints))
return endPoints[index]
}
func handleConnection(r, w net.Conn) {
defer r.Close()
defer w.Close()
var buffer = make([]byte, 100000)
for {
n, err := r.Read(buffer)
if err != nil {
break
}
n, err = w.Write(buffer[:n])
if err != nil {
break
}
}
}
配置文件tcp_map.json如下：
{
"host":{
"ipstr":"0.0.0.0:10002"
},
"maplist":[{
"ipstr":"127.0.0.1:3306"
},{
"ipstr":"120.79.6.168:3306"
}]
}
