用golang实现tcp端口扫描器
tcp端口扫描器 就是针对某一IP地址，扫描某个范围内的端口是否打开。
1. 非并发版本实现
package main
import (
"fmt"
"net"
)
func main() {
ip := "11.111.10.11"
startPort := 21
endPort := 120
for port := startPort; port < endPort; port++ {
address := fmt.Sprintf("%s:%d", ip, port)
conn, err := net.Dial("tcp", address)
if err != nil {
fmt.Printf("%s 关闭了\n", address)
continue
}
conn.Close()
fmt.Printf("%s 打开了\n", address)
}
}
注：url，初始扫描端口，结束扫描端口可以自己更改
非并发下，代码执行时间特别慢。
2. 并发版本实现
并发版本使用goroutine + WaitGroup的形式。
WaitGroup本质上是一个计数器，起阻塞作用，让所有的goroutine执行完再结束。
package main
import (
"fmt"
"net"
"sync"
"time"
)
func main() {
start := time.Now()
var wg sync.WaitGroup
ip := "11.111.10.11"
startPort := 21
endPort := 120
for port := startPort; port < endPort; port++ {
wg.Add(1)
go func(j int) {
defer wg.Done()
address := fmt.Sprintf("%s:%d", ip, j)
conn, err := net.Dial("tcp", address)
if err != nil {
fmt.Printf("%s 关闭了\n", address)
return
}
conn.Close()
fmt.Printf("%s 打开了\n", address)
}(port)
}
wg.Wait()
elapsed := time.Since(start) / 1e9
fmt.Printf("%d seconds", elapsed)
}
3. goroutine池并发版本实现
可以使用另外一个管道results来阻塞。
package main
import (
"fmt"
"net"
"time"
)
var ip = "11.111.10.11"
func worker(ports chan int, results chan int) {
for port := range ports {
address := fmt.Sprintf("%s:%d", ip, port)
conn, err := net.Dial("tcp", address)
if err != nil {
// fmt.Printf("%s 关闭了\n", address)
results <- 0
continue
}
conn.Close()
// fmt.Printf("%s 打开了\n", address)
results <- port
}
}
func main() {
start := time.Now()
ports := make(chan int, 100)
results := make(chan int)
var openPort []int
for i := 0; i < cap(ports); i++ {
go worker(ports, results)
}
startPort := 21
endPort := 120
go func() {
for port := startPort; port < endPort; port++ {
ports <- port
}
}()
for p := startPort; p < endPort; p++ {
port := <-results
if port != 0 {
openPort = append(openPort, port)
}
}
elapsed := time.Since(start) / 1e9
fmt.Printf("%d seconds", elapsed)
}
