An article explaining in detail how to implement a port scanner in Go-Golang-php.cn

An article explaining in detail how to implement a port scanner in Go

藏色散人

Release： 2023-04-14 16:53:31

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This article brings you relevant knowledge about Go. It mainly introduces how to implement the port scanner in Go. There are code examples. Friends who are interested can take a look below. I hope it will be helpful to you.

Use GO to scan server ports in batches

1. Port scanner V1 - basic operation

package mainimport (
    "fmt"
    "net"
    "time"
    "unsafe")func main() {
    tcpScan("127.0.0.1", 1, 65535)}func tcpScan(ip string, portStart int, portEnd int) {
    start := time.Now()

    // 参数校验
    isok := verifyParam(ip, portStart, portEnd)
    if isok == false {
        fmt.Printf("[Exit]\n")
    }

    for i := portStart; i <= portEnd; i++ {
        address := fmt.Sprintf("%s:%d", ip, i)
        conn, err := net.Dial("tcp", address)
        if err != nil {
            fmt.Printf("[info] %s Close \n", address)
            continue
        }
        conn.Close()
        fmt.Printf("[info] %s Open \n", address)
    }

    cost := time.Since(start)
    fmt.Printf("[tcpScan] cost %s second \n", cost)}func verifyParam(ip string, portStart int, portEnd int) bool {
    netip := net.ParseIP(ip)
    if netip == nil {
        fmt.Println("[Error] ip type is must net.ip")
        return false
    }
    fmt.Printf("[Info] ip=%s | ip type is: %T | ip size is: %d \n", netip, netip, unsafe.Sizeof(netip))

    if portStart < 1 || portEnd > 65535 {
        fmt.Println("[Error] port is must in the range of 1~65535")
        return false
    }
    fmt.Printf("[Info] port start:%d end:%d \n", portStart, portEnd)

    return true}

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2. Port scanner V2 - using goroutine

package mainimport (
    "fmt"
    "net"
    "sync"
    "time"
    "unsafe")func main() {
    tcpScanByGoroutine("127.0.0.1", 1, 65535)}func tcpScanByGoroutine(ip string, portStart int, portEnd int) {
    start := time.Now()
    // 参数校验
    isok := verifyParam(ip, portStart, portEnd)
    if isok == false {
        fmt.Printf("[Exit]\n")
    }

    var wg sync.WaitGroup    for i := portStart; i <= portEnd; i++ {
        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("[info] %s Close \n", address)
                return
            }
            conn.Close()
            fmt.Printf("[info] %s Open \n", address)
        }(i)
    }
    wg.Wait()

    cost := time.Since(start)
    fmt.Printf("[tcpScanByGoroutine] cost %s second \n", cost)}func verifyParam(ip string, portStart int, portEnd int) bool {
    netip := net.ParseIP(ip)
    if netip == nil {
        fmt.Println("[Error] ip type is must net.ip")
        return false
    }
    fmt.Printf("[Info] ip=%s | ip type is: %T | ip size is: %d \n", netip, netip, unsafe.Sizeof(netip))

    if portStart < 1 || portEnd > 65535 {
        fmt.Println("[Error] port is must in the range of 1~65535")
        return false
    }
    fmt.Printf("[Info] port start:%d end:%d \n", portStart, portEnd)

    return true}

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3. Port Scanner V3 - Using Goroutine Channel

package mainimport (
    "fmt"
    "net"
    "sync"
    "time"
    "unsafe")func main() {
    tcpScanByGoroutineWithChannel("127.0.0.1", 1, 65535)}func handleWorker(ip string, ports chan int, wg *sync.WaitGroup) {
    for p := range ports {
        address := fmt.Sprintf("%s:%d", ip, p)
        conn, err := net.Dial("tcp", address)
        if err != nil {
            fmt.Printf("[info] %s Close \n", address)
            wg.Done()
            continue
        }
        conn.Close()
        fmt.Printf("[info] %s Open \n", address)
        wg.Done()
    }}func tcpScanByGoroutineWithChannel(ip string, portStart int, portEnd int) {
    start := time.Now()

    // 参数校验
    isok := verifyParam(ip, portStart, portEnd)
    if isok == false {
        fmt.Printf("[Exit]\n")
    }

    ports := make(chan int, 100)
    var wg sync.WaitGroup    for i := 0; i < cap(ports); i++ {
        go handleWorker(ip, ports, &wg)
    }

    for i := portStart; i <= portEnd; i++ {
        wg.Add(1)
        ports <- i    }

    wg.Wait()
    close(ports)

    cost := time.Since(start)
    fmt.Printf("[tcpScanByGoroutineWithChannel] cost %s second \n", cost)}func verifyParam(ip string, portStart int, portEnd int) bool {
    netip := net.ParseIP(ip)
    if netip == nil {
        fmt.Println("[Error] ip type is must net.ip")
        return false
    }
    fmt.Printf("[Info] ip=%s | ip type is: %T | ip size is: %d \n", netip, netip, unsafe.Sizeof(netip))

    if portStart < 1 || portEnd > 65535 {
        fmt.Println("[Error] port is must in the range of 1~65535")
        return false
    }
    fmt.Printf("[Info] port start:%d end:%d \n", portStart, portEnd)

    return true}

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4 Port Scanner V4 - Introducing two Channel

// packagepackage mainimport (
    "fmt"
    "net"
    "sort"
    "time"
    "unsafe")func main() {
    tcpScanByGoroutineWithChannelAndSort("127.0.0.1", 1, 65535)}// The function handles checking if ports are open or closed for a given IP address.func handleWorker(ip string, ports chan int, results chan int) {
    for p := range ports {
        address := fmt.Sprintf("%s:%d", ip, p)
        conn, err := net.Dial("tcp", address)
        if err != nil {
            // fmt.Printf("[debug] ip %s Close \n", address)
            results <- (-p)
            continue
        }
        // fmt.Printf("[debug] ip %s Open \n", address)
        conn.Close()
        results <- p    }}func tcpScanByGoroutineWithChannelAndSort(ip string, portStart int, portEnd int) {
    start := time.Now()

    // 参数校验
    isok := verifyParam(ip, portStart, portEnd)
    if isok == false {
        fmt.Printf("[Exit]\n")
    }

    ports := make(chan int, 50)
    results := make(chan int)
    var openSlice []int
    var closeSlice []int

    // 任务生产者-分发任务 (新起一个 goroutinue ，进行分发数据)
    go func(a int, b int) {
        for i := a; i <= b; i++ {
            ports <- i        }
    }(portStart, portEnd)

    // 任务消费者-处理任务  (每一个端口号都分配一个 goroutinue ，进行扫描)
    // 结果生产者-每次得到结果 再写入 结果 chan 中
    for i := 0; i < cap(ports); i++ {
        go handleWorker(ip, ports, results)
    }

    // 结果消费者-等待收集结果 (main中的 goroutinue 不断从 chan 中阻塞式读取数据)
    for i := portStart; i <= portEnd; i++ {
        resPort := <-results        if resPort > 0 {
            openSlice = append(openSlice, resPort)
        } else {
            closeSlice = append(closeSlice, -resPort)
        }
    }

    // 关闭 chan
    close(ports)
    close(results)

    // 排序
    sort.Ints(openSlice)
    sort.Ints(closeSlice)

    // 输出
    for _, p := range openSlice {
        fmt.Printf("[info] %s:%-8d Open\n", ip, p)
    }
    // for _, p := range closeSlice {
    //     fmt.Printf("[info] %s:%-8d Close\n", ip, p)
    // }

    cost := time.Since(start)
    fmt.Printf("[tcpScanByGoroutineWithChannelAndSort] cost %s second \n", cost)}func verifyParam(ip string, portStart int, portEnd int) bool {
    netip := net.ParseIP(ip)
    if netip == nil {
        fmt.Println("[Error] ip type is must net.ip")
        return false
    }
    fmt.Printf("[Info] ip=%s | ip type is: %T | ip size is: %d \n", netip, netip, unsafe.Sizeof(netip))

    if portStart < 1 || portEnd > 65535 {
        fmt.Println("[Error] port is must in the range of 1~65535")
        return false
    }
    fmt.Printf("[Info] port start:%d end:%d \n", portStart, portEnd)

    return true}

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