refactor: move magicpacket code to pkg dir

cmd/gowake/gowake.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"regexp"
 
-	"github.com/jedrw/gowake"
 	"github.com/jedrw/gowake/cmd/listen"
+	"github.com/jedrw/gowake/pkg/magicpacket"
 	"github.com/spf13/cobra"
 )
 
@@ -33,14 +33,14 @@ var gowakeCmd = &cobra.Command{
 		}
 
 		// Build packet
-		mp, err := gowake.NewMagicPacket(args[0])
+		mp, err := magicpacket.New(args[0])
 		if err != nil {
 			fmt.Println(err.Error())
 			return
 		}
 
 		// Send packet
-		err = gowake.SendMagicPacket(mp, ip, port)
+		err = magicpacket.Send(mp, ip, port)
 		if err != nil {
 			fmt.Println(err.Error())
 		}

cmd/listen/listen.go

@@ -3,7 +3,7 @@ package listen
 import (
 	"fmt"
 
-	"github.com/jedrw/gowake"
+	"github.com/jedrw/gowake/pkg/magicpacket"
 	"github.com/spf13/cobra"
 )
 
@@ -15,13 +15,13 @@ var ListenCmd = &cobra.Command{
 		cont, _ := cmd.Flags().GetBool("continuous")
 		fmt.Printf("Listening for magic packets on port %d:\n", port)
 		for {
-			remote, mac, err := gowake.Listen(port)
+			remote, mac, err := magicpacket.Listen(port)
 			if err != nil {
 				if err.Error() == fmt.Sprintf("listen udp 0.0.0.0:%d: bind: permission denied", port) {
 					fmt.Println("Please run as elevated user")
 					return
 				} else {
-					fmt.Println(err.Error())
+					fmt.Println(err)
 					return
 				}
 			}

pkg/magicpacket/listen.go

@@ -0,0 +1,38 @@
+package magicpacket
+
+import (
+	"bytes"
+	"fmt"
+	"net"
+)
+
+func Listen(port int) (*net.UDPAddr, string, error) {
+	addr := net.UDPAddr{
+		IP:   net.ParseIP("0.0.0.0"),
+		Port: port,
+	}
+
+	listener, err := net.ListenUDP("udp", &addr)
+	if err != nil {
+		return nil, "", err
+	}
+	defer listener.Close()
+
+	var magicPacket MagicPacket
+	remote := &net.UDPAddr{}
+	_, remote, err = listener.ReadFromUDP(magicPacket[:])
+	if err != nil {
+		return remote, "", err
+	}
+
+	macLength := 6
+	offset := 6
+	for i := 0; i < 16; i++ {
+		if !bytes.Equal(magicPacket[offset:offset+macLength], magicPacket[96:]) {
+			return remote, "", fmt.Errorf("received malformed magicpacket from %v", remote)
+		}
+		offset += 6
+	}
+
+	return remote, net.HardwareAddr.String(magicPacket[96:]), err
+}

magicpacket.go → pkg/magicpacket/magicpacket.go

@@ -1,4 +1,4 @@
-package gowake
+package magicpacket
 
 import (
 	"fmt"
@@ -7,7 +7,7 @@ import (
 
 type MagicPacket [102]byte
 
-func NewMagicPacket(mac string) (MagicPacket, error) {
+func New(mac string) (MagicPacket, error) {
 	// Parse mac address
 	hwAddr, err := net.ParseMAC(mac)
 	if err != nil {

send.go → pkg/magicpacket/send.go

@@ -1,11 +1,11 @@
-package gowake
+package magicpacket
 
 import (
 	"fmt"
 	"net"
 )
 
-func SendMagicPacket(packet MagicPacket, ip string, port int) error {
+func Send(packet MagicPacket, ip string, port int) error {
 	conn, err := net.Dial("udp", fmt.Sprintf("%s:%d", ip, port))
 	if err != nil {
 		return err