在go语言中使用Goroutine + Channel实现端口扫描器代码示例

端口扫描器，顾名思义就是用来批量扫描服务器端口的。

使用Goroutine + Channel的方式，示例代码：

package main

import (
    "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
}

进一步优化，引入两个Channel方式，示例代码：

package main

import (
    "fmt"
    "net"
    "sort"
    "time"
    "unsafe"
)

func main() {
    tcpScanByGoroutineWithChannelAndSort("127.0.0.1", 1, 65535)
}

//该函数用于检查一个给定的IP地址的端口是否开放或关闭
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
}