Go语言net模块TCP和UDP编程实践
任何一种语言TCP和UDP网络编程总是必须的，接下来就将go语言中使用net标准库进行TCP和UDP编程进行梳理总结。
目录
1.代码结构
2.TCP通信
server.go
package main
import (
"fmt"
"net"
)
func main() {
//1.监听端口
listen, err := net.Listen("tcp", "0.0.0.0:18383")
if err != nil {
fmt.Println("listen failed, err:", err)
return
}
fmt.Println("listen Start...")
for {
//2.接收客户端连接
conn, err := listen.Accept()
if err != nil {
fmt.Printf("accept failed, err:%vn", err)
continue
}
//3.开启Goroutine处理连接
go process(conn)
}
}
// 处理请求，类型就是net.Conn
func process(conn net.Conn) {
//处理结束后关闭链接
defer conn.Close()
for {
var buf [128]byte
n, err := conn.Read(buf[:])
if err != nil {
fmt.Printf("read from conn failed, err: %v", err)
break
}
fmt.Printf("recv from client, content: %vn", string(buf[:n]))
}
}
client.go
package main
import (
"bufio"
"fmt"
"net"
"os"
"strings"
)
func main() {
conn, err := net.Dial("tcp", "0.0.0.0:18383")
if err != nil {
fmt.Printf("dial failed, err: %vn", err)
return
}
fmt.Println("conn established...")
reader := bufio.NewReader(os.Stdin)
for {
data, err := reader.ReadString('n')
if err != nil {
fmt.Printf("read from console failed, err:%vn", err)
break
}
data = strings.TrimSpace(data)
_, err = conn.Write([]byte(data))
if err != nil {
fmt.Printf("write failed, err:%vn", err)
break
}
}
}
运行结果：
3.UDP通信
server.go
package main
import (
"fmt"
"net"
)
func main() {
//建立一个UDP的监听，这里使用的是ListenUDP，并且地址是一个结构体
listen, err := net.ListenUDP("udp", &net.UDPAddr{
IP: net.IPv4(0, 0, 0, 0),
Port: 8080,
})
if err != nil {
fmt.Printf("listen failed, err:%vn", err)
return
}
for {
var data [1024]byte
//读取UDP数据
count, addr, err := listen.ReadFromUDP(data[:])
if err != nil {
fmt.Printf("read udp failed, err:%vn", err)
continue
}
fmt.Printf("recv data: %s addr: %v count: %dn", string(data[0:count]), addr, count)
//返回数据
_, err = listen.WriteToUDP([]byte("hello client, I am UDP server ^_^ ^_^"), addr)
if err != nil {
fmt.Printf("write udp failed, err:%vn", err)
continue
}
}
}
client.go
package main
import (
"fmt"
"net"
)
func main() {
// 创建连接
socket, err := net.DialUDP("udp4", nil, &net.UDPAddr{
IP: net.IPv4(127, 0, 0, 1),
Port: 8080,
})
if err != nil {
fmt.Println("连接失败!", err)
return
}
defer socket.Close()
// 发送数据
senddata := []byte("hello server, I am UDP client !")
_, err = socket.Write(senddata)
if err != nil {
fmt.Println("发送数据失败!", err)
return
}
// 接收数据
data := make([]byte, 4096)
read, remoteAddr, err := socket.ReadFromUDP(data)
if err != nil {
fmt.Println("读取数据失败!", err)
return
}
fmt.Println(read, remoteAddr)
fmt.Printf("%sn", data)
}
运行结果：
4.TCP模拟HTTP协议通信
server.go
package main
import (
"fmt"
"net/http"
)
func main() {
//http://127.0.0.1:8181/hello
http.HandleFunc("/hello", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("Hello world !"))
fmt.Println("recv client connect ...")
})
server := http.Server{
Addr: "127.0.0.1:8181",
Handler: nil, // 对应DefaultServeMux路由
}
server.ListenAndServe()
}
client.go
package main
import (
"fmt"
"io"
"net"
)
func conn_baidu() {
conn, err := net.Dial("tcp", "www.baidu.com:80")
if err != nil {
fmt.Printf("dial failed, err:%vn", err)
return
}
data := "GET / HTTP/1.1rn"
data += "HOST: www.baidu.comrn"
data += "connection: closern"
data += "rnrn"
//写入数据
_, err = io.WriteString(conn, data)
if err != nil {
fmt.Printf("wirte string failed, err:%vn", err)
return
}
var buf [1024]byte
for {
//读取返回的数据
n, err := conn.Read(buf[:])
if err != nil || n == 0 {
break
}
fmt.Println(string(buf[:n]))
}
}
func conn_myself() {
conn, err := net.Dial("tcp", "127.0.0.1:8181")
if err != nil {
fmt.Printf("dial failed, err:%vn", err)
return
}
data := "GET /hello HTTP/1.1rn"
data += "HOST: 127.0.0.1rn"
data += "connection: closern"
data += "rnrn"
//写入数据
_, err = io.WriteString(conn, data)
if err != nil {
fmt.Printf("wirte string failed, err:%vn", err)
return
}
var buf [1024]byte
for {
//读取返回的数据
n, err := conn.Read(buf[:])
if err != nil || n == 0 {
break
}
fmt.Println(string(buf[:n]))
}
}
func main() {
conn_myself()
}
运行结果：
5.利用TCP扫描那些端口被占用
port_scan.go
package main
import (
"flag"
"log"
"net"
"strconv"
"strings"
"sync"
"time"
)
func processPortItem(port string) []string {
var ports []string
arr := strings.Split(port, ",")
for _, p := range arr {
if strings.Contains(p, "-") {
ports = append(ports, rangeToArr(p)...)
} else {
ports = append(ports, p)
}
}
return ports
}
func rangeToArr(s string) []string {
if strings.Contains(s, "-") {
var arr []string
from, _ := strconv.Atoi(strings.Split(s, "-")[0])
to, _ := strconv.Atoi(strings.Split(s, "-")[1])
if from == 0 {
from = 1
}
if to == 0 {
to = 65535
}
for i := from; i <= to; i++ {
arr = append(arr, strconv.Itoa(i))
}
return arr
} else {
return []string{s}
}
}
func scan(ip string, port string, wg *sync.WaitGroup) {
conn, err := net.DialTimeout("tcp", ip+":"+port, time.Second)
if err != nil {
wg.Done()
return
}
wg.Done()
defer conn.Close()
log.Println(ip, port, "port use ！")
}
func main() {
ip := flag.String("h", "127.0.0.1", "scan IP")
port := flag.String("p", "1-65536", "scan port")
flag.Parse()
log.Println("scan info is ：", *ip, *port)
//线程同步
wg := &sync.WaitGroup{}
for _, p := range processPortItem(*port) {
wg.Add(1)
go scan(*ip, p, wg)
}
wg.Wait()
}
运行结果：
