Question

我正在编写简单的网络扫描仪，并停留在通过端口号解析服务名称的过程中。最好的方法是什么？我以为它应该类似于python的socket.getservbyport()并创建了this lib，但是很遗憾，Dev环境基于Windows，我也希望内置解决方案而不是解析器。

package main

import (
    "fmt"
    "net"
    "strings"
    "sync"
    "time"
)

type PortScanner struct {
    ip string
}

func ScanPort(ip string, port int, timeout time.Duration) {
    target := fmt.Sprintf("%s:%d", ip, port)
    conn, err := net.DialTimeout("tcp", target, timeout)
    if err != nil {
        if strings.Contains(err.Error(), "too many open files") {
            time.Sleep(timeout)
            ScanPort(ip, port, timeout)
        }
        return
    }

    if err = conn.Close(); err != nil {
        fmt.Println(err)
    }
    fmt.Println(port, "open")
}

func (ps *PortScanner) Start(f, l int, timeout time.Duration) {
    wg := sync.WaitGroup{}
    defer wg.Wait()

    for port := f; port <= l; port++ {
        wg.Add(1)
        go func(port int) {
            defer wg.Done()
            ScanPort(ps.ip, port, timeout)
        }(port)
    }
}

func main() {
    ps := &PortScanner{ip: "127.0.0.1"}
    ps.Start(1, 65535, 500*time.Millisecond)
}

Answer 1

您可以修改该netdb库中的代码以加载您提供的instead of /etc/services的services文件。

也许更好，因为这实际上只是键/值映射，因此可以创建一个ports.go文件：

var tcpPorts = map[int]string{
    80: "http"
    // ...
}

然后进行常规地图查找。

要列出所有TCP端口，您可以执行以下操作：

$ sed -E '/tcp$/!d; s!^([a-zA-Z0-9\-]+)\s+([0-9]+)/\w+!\t\2: "\1",!;' /etc/services
1: "tcpmux",
2: "compressnet",
3: "compressnet",
5: "rje",
7: "echo",
9: "discard",
11: "systat",
13: "daytime",
17: "qotd",
19: "chargen",
.. many more ..

通过端口获取服务名称

1 个答案: