Go Wake-On-Lan

go-wol.go

package main

import (
        "net"
        "os"
        "strings"
        "encoding/hex"
        "fmt"
)

func main() {
    if len(os.Args) != 2 {
        fmt.Fprintf(os.Stderr, "Usage: %s 00:01:02:03:04:05\n", os.Args[0])
                    os.Exit(1)
    } else {
        if len(os.Args[1]) != 17 {
            fmt.Fprintf(os.Stderr, "%s invalid mac!\n", os.Args[1])
                        os.Exit(1)
        }
    }
    BROADCAST_IPv4 := net.IPv4(255, 255, 255, 255)
    socket,_ := net.DialUDP("udp4", nil, &net.UDPAddr{BROADCAST_IPv4,9})
    buf := make([]byte,102)
    buf = []byte{'\xFF','\xFF','\xFF','\xFF','\xFF','\xFF'}
    // parse 
    mac1 := strings.Split(os.Args[1],":")
    buf_mac := make([]byte, len(mac1))
    for i:=0;i<len(mac1);i++ {
        mac2,_ := hex.DecodeString(mac1[i]) 
        buf_mac[i] = mac2[0]
    }
    // append
    for i:=0;i<16;i++ {
        buf = append(buf, buf_mac...)
    }
    // send 
    fmt.Printf("Wake-On-Lan packet sent to MAC address %s\n", os.Args[1])
    socket.Write(buf)
}