What！！！ so fast

[ip]
10.27.3.1
10.27.3.2
10.27.3.3
10.27.3.4
10.27.3.5
10.27.3.6
......
10.27.3.254
127.0.0.1
[port]
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309

package main
import (

    "fmt"
    "io/ioutil"
    "bufio"
    "log"
    "regexp"
    "net"
    "runtime"
    "time"
    "bytes"
    "flag"
    "os"
    "strings"

)

var(


    P = fmt.Println

)

//首先从命令行中读取线程数和配置文件路径
//从配置文件中解析出ip和port
//配置文件格式为
// [ip]
// 127.0.0.1
// [port]
// 22
// 36000
// 56000
// 3306
//根据开启的线程数对指定ip和端口进行tcp连接
//如果端口开启，把ip:port按照格式返回

func Scanner(configFile string, limit int){

    runtime.GOMAXPROCS(runtime.NumCPU())
    data, err := ioutil.ReadFile(configFile)
    portlist := make([]string,0,10)

    if err != nil{
        log.Fatal(err)
        panic(err)
    }

    ip_index := bytes.Index(data,[]byte("[ip]"))

    port_index := bytes.Index(data,[]byte("[port]"))

    if ip_index < 0{

        P("文件格式有误: missing [ip]")
        return
    }

    if port_index <0{

        portlist = append(portlist,"22")
        portlist = append(portlist,"36000")
        portlist = append(portlist,"56000")
        portlist = append(portlist,"3306")

    }else{
        reg_port := regexp.MustCompile(`\d+`)
        var ports [][]byte

        if ip_index>port_index{
            ports = reg_port.FindAll(data[:ip_index],-1)

        }else{

            ports = reg_port.FindAll(data[port_index:],-1)
        }


        for _,v := range(ports){

            portlist = append(portlist,string(v))

        } 
    }


    reg_ip := regexp.MustCompile(`((25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d)))\.){3}(25[0-5]|2[0-4]\d|((1\d{2})|([1-9]?\d)))`)

    ips := reg_ip.FindAll(data,-1)

    input := make(chan []byte, len(ips))

    result := make(chan string, len(ips))

    defer close(input)
    defer close(result)

    for _, v := range(ips){
        input <- v
    }
    //控制多少并发
    for i:=0; i<limit;i++{
        //这个时候可以启动扫描函数
        go ScanPort(portlist,input,result)

    }

    result_str := ""

    for i :=0; i< len(ips);i++{

        //将扫描的结果输出
        ip_result,ok:= <-result

        if !strings.Contains(ip_result,"ok"){
            P(ip_result)
            result_str += ip_result+"\n"


        }

        if !ok {


            break;
        }

    }

    f,err := os.Create("result.txt")
    if err !=nil{

        P(err)
        return
    }
    defer f.Close()
    w := bufio.NewWriter(f)

    fmt.Fprintln(w, result_str)

    w.Flush()

}

func ScanPort(portlist []string,intput chan []byte,result chan string ) {

    for{

        task,ok := <-intput

        if !ok{

            return
        }
        ip := string(task)
        P("scaning ",ip,"port",portlist)
        port_str :=""
        for i:=0; i<len(portlist); i++{
            _, err  := net.DialTimeout("tcp", ip+":"+portlist[i], time.Second*3)

            if err != nil{
                continue
            }
            port_str+=portlist[i]+" "
        }

        if len(port_str) >0{
            //说明有打开的端口
            // P(ip+":"+port_str+"open")
            result <- ip+"----"+"1"+"----"+"open port:"+port_str

        }else{
            result <- ip+"----"+"0"+"----"+"ok"
        }

    }

}