multitcp.go

package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net"
	"sync"
	"time"
)

func main() {
	tasksNum := flag.Int("num", 10, "number of requests")
	addr := flag.String("addr", "127.0.0.1:80", "address of request")
	resultFile := flag.String("file", "/tmp/ddos", "file stored success ratio")

	flag.Parse()

	beg := time.Now()
	successNum := 0
	wg := &sync.WaitGroup{}
	for i := 0; i < *tasksNum; i++ {
		wg.Add(1)
		go func(addr string, group *sync.WaitGroup) {
			err := establishConn(addr)
			if err == nil {
				successNum++
			}
			group.Done()
		}(*addr, wg)
	}
	wg.Wait()
	fmt.Printf("time consumed: %fs\n", time.Now().Sub(beg).Seconds())
	successRatio := float32(successNum) / float32(*tasksNum)
	fmt.Printf("success ratio: %d, %f\n", successNum, successRatio)
	if err := ioutil.WriteFile(*resultFile, []byte(fmt.Sprintf("%f", successRatio)), 0777); err != nil {
		log.Fatalf("write file error: %v", err)
	}
}

func establishConn(addr string) error {
	_, err := net.Dial("tcp", addr)
	if err != nil {
		log.Printf("%s: dial error: %s", addr, err)
		return err
	}
	// log.Println(i, ":connect to server ok")
	return nil
}