From 029f90de6895b68b5f3d1999858b09d055429679 Mon Sep 17 00:00:00 2001
From: Ethel Morgan <eth@ethulhu.co.uk>
Date: Fri, 19 Jun 2020 23:50:49 +0100
Subject: basic wake-on-lan actuator
---
wakeonlan/wakeonlan.go | 43 +++++++++++++++++++++++++++++++++++++++++++
wakeonlan/wakeonlan_test.go | 42 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+)
create mode 100644 wakeonlan/wakeonlan.go
create mode 100644 wakeonlan/wakeonlan_test.go
(limited to 'wakeonlan')
diff --git a/wakeonlan/wakeonlan.go b/wakeonlan/wakeonlan.go
new file mode 100644
index 0000000..803d27f
--- /dev/null
+++ b/wakeonlan/wakeonlan.go
@@ -0,0 +1,43 @@
+// Package wakeonlan implements Wake-On-Lan.
+package wakeonlan
+
+import (
+ "bytes"
+ "encoding/binary"
+ "fmt"
+ "net"
+)
+
+var (
+ header = []byte{0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}
+
+ broadcastAddr = &net.UDPAddr{
+ IP: net.IPv4bcast,
+ Port: 9,
+ }
+)
+
+// Wake sends the Magic Packet to wake the computer with the given MAC address.
+func Wake(mac net.HardwareAddr) error {
+ conn, err := net.DialUDP("udp", nil, broadcastAddr)
+ if err != nil {
+ return fmt.Errorf("could not create UDP broadcast: %w", err)
+ }
+ defer conn.Close()
+
+ payload := packet(mac)
+
+ if _, err := conn.Write(payload); err != nil {
+ return fmt.Errorf("could not send Magic Packet: %w", err)
+ }
+ return nil
+}
+
+func packet(mac net.HardwareAddr) []byte {
+ var buf bytes.Buffer
+ binary.Write(&buf, binary.BigEndian, header)
+ for i := 0; i < 16; i++ {
+ binary.Write(&buf, binary.BigEndian, mac)
+ }
+ return buf.Bytes()
+}
diff --git a/wakeonlan/wakeonlan_test.go b/wakeonlan/wakeonlan_test.go
new file mode 100644
index 0000000..245d580
--- /dev/null
+++ b/wakeonlan/wakeonlan_test.go
@@ -0,0 +1,42 @@
+package wakeonlan
+
+import (
+ "encoding/hex"
+ "net"
+ "reflect"
+ "testing"
+)
+
+func TestPacket(t *testing.T) {
+ tests := []struct {
+ mac string
+ packet string
+ }{
+ {
+ "a8:23:22:ad:be:c7",
+ "ffffffffffffa82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7a82322adbec7",
+ },
+ }
+
+ for i, test := range tests {
+ mac, err := net.ParseMAC(test.mac)
+ if err != nil {
+ t.Fatalf("invalid MAC address %q: %v", test.mac, err)
+ }
+
+ if len(test.packet) != 102 {
+ if err != nil {
+ t.Fatalf("invalid packet length address: found %v, want 102", len(test.packet))
+ }
+ }
+ want, err := hex.DecodeString(test.packet)
+ if err != nil {
+ t.Fatalf("invalid hex string: %v", err)
+ }
+
+ got := packet(mac)
+ if !reflect.DeepEqual(want, got) {
+ t.Errorf("[test %d]\nwanted %v\nlen %d\ngot %v\nlen %d", i, want, len(want), got, len(got))
+ }
+ }
+}
--
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