goroutineを使って高速TCP ポートスキャン

package main

import (
    "fmt"
    "net"
    "os"
)

func main() {
    host := os.Args[1]
    port := os.Args[2]
    address := fmt.Sprint(host, ":", port)
    _, err := net.Dial("tcp", address)
    if err == nil {
        fmt.Println("Connection successful")
    }
}

$ go run main.go <IP Address> 22  
Connection successful

package main

import (
    "fmt"
    "net"
    "os"
    "strconv"
    "time"
)

func main() {
    var openPorts []int
    host := os.Args[1]
    ports, _ := strconv.Atoi(os.Args[2])

    start := time.Now()
    for i := 0; i <= ports; i++ {
        address := fmt.Sprintf("%s:%d", host, i)
        conn, err := net.DialTimeout("tcp", address, time.Duration(1)*time.Second)
        if err != nil {
            continue
        }
        conn.Close()
        openPorts = append(openPorts, i)
    }
    end := time.Now()

    for _, p := range openPorts {
        fmt.Printf("Opening %d port\n", p)
    }
    fmt.Printf("Done!! Took %f seconds\n", (end.Sub(start)).Seconds())
}

$ go run main.go localhost 1023
Opening 631 port
Opening 1023 port
Done!! Took 16.926570 seconds

package main

import (
    "fmt"
    "net"
    "os"
    "strconv"
    "sync"
    "time"
)

func scanner(buffer chan int, host string, openPorts chan int) {
    // ❺
    for p := range buffer {
        conn, err := net.DialTimeout("tcp", fmt.Sprintf("%s:%d", host, p), time.Duration(1)*time.Second)
        if err != nil {
            continue
        }
        conn.Close()
        openPorts <- p
    }
}

func main() {
    var results []int

    host := os.Args[1]
    maxPort, _ := strconv.Atoi(os.Args[2])
    worker, _ := strconv.Atoi(os.Args[3])

    buffer := make(chan int, worker) // ❶
    openPorts := make(chan int)      // ❷

    var wg sync.WaitGroup
    wg.Add(worker)

    for i := 0; i < worker; i++ {
        go func() {
            scanner(buffer, host, openPorts) // ❸
            wg.Done()
        }()
    }

    go func() {
        wg.Wait()
        close(openPorts) // ❻
    }()

    start := time.Now()
    go func() {
        for p := 0; p <= maxPort; p++ {
            buffer <- p // ❹
        }
        close(buffer)
    }()

    for p := range openPorts {
        results = append(results, p)
    }

    end := time.Now()

    for _, p := range results {
        fmt.Printf("Opening %d port\n", p)
    }

    fmt.Printf("Done!! Took %f seconds\n", (end.Sub(start)).Seconds())
}

# goroutineを1個起動して実行(worker = 1)
$ go run main.go localhost 1023 1
Opening 631 port
Opening 1023 port
Done!! Took 15.974225 seconds

# goroutineを10個起動して再実行(worker = 10)
$ go run main.go localhost 1023 10
Opening 631 port
Opening 1023 port
Done!! Took 13.226174 seconds

# goroutineを100個起動して再実行(worker = 100)
$ go run main.go localhost 1023 100
Opening 631 port
Opening 1023 port
Done!! Took 6.061187 seconds

# goroutineを1000個起動して再実行(worker = 1000)
$ go run main.go localhost 1023 1000
Opening 631 port
Opening 1023 port
Done!! Took 2.007343 seconds

❶Lambda -> SQS -> ❷Lmabda -> ❸SNS -> Lmabda