basic wake-on-lan actuator

8 files changed, 258 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..d506db3
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+*.json
+/catbus-actuator-wakeonlan
diff --git a/config/config.go b/config/config.go
new file mode 100644
index 0000000..2d19506
--- /dev/null
+++ b/config/config.go
@@ -0,0 +1,66 @@
+package config
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net"
+)
+
+type (
+	Config struct {
+		Broker string
+
+		MACsByTopic map[string]net.HardwareAddr
+	}
+
+	config struct {
+		MQTTBroker string `json:"mqttBroker"`
+		Devices    map[string]struct {
+			MAC   mac    `json:"mac"`
+			Topic string `json:"topic"`
+		} `json:"devices"`
+	}
+
+	mac struct {
+		net.HardwareAddr
+	}
+)
+
+func ParseFile(path string) (*Config, error) {
+	bytes, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+
+	raw := config{}
+	if err := json.Unmarshal(bytes, &raw); err != nil {
+		return nil, err
+	}
+
+	return configFromConfig(raw), nil
+}
+
+func configFromConfig(raw config) *Config {
+	c := &Config{
+		Broker:      raw.MQTTBroker,
+		MACsByTopic: map[string]net.HardwareAddr{},
+	}
+
+	for _, v := range raw.Devices {
+		c.MACsByTopic[v.Topic] = v.MAC.HardwareAddr
+	}
+
+	return c
+}
+
+func (m mac) MarshalText() ([]byte, error) {
+	return []byte(m.String()), nil
+}
+func (m *mac) UnmarshalText(raw []byte) error {
+	mm, err := net.ParseMAC(string(raw))
+	if err != nil {
+		return err
+	}
+	m.HardwareAddr = mm
+	return nil
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..c4ce0c1
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,8 @@
+module go.eth.moe/catbus-actuator-wakeonlan
+
+go 1.14
+
+require (
+	github.com/eclipse/paho.mqtt.golang v1.2.0
+	golang.org/x/net v0.0.0-20200602114024-627f9648deb9 // indirect
+)
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..d996e7c
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,8 @@
+github.com/eclipse/paho.mqtt.golang v1.2.0 h1:1F8mhG9+aO5/xpdtFkW4SxOJB67ukuDC3t2y2qayIX0=
+github.com/eclipse/paho.mqtt.golang v1.2.0/go.mod h1:H9keYFcgq3Qr5OUJm/JZI/i6U7joQ8SYLhZwfeOo6Ts=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20200602114024-627f9648deb9 h1:pNX+40auqi2JqRfOP1akLGtYcn15TUbkhwuCO3foqqM=
+golang.org/x/net v0.0.0-20200602114024-627f9648deb9/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..219cf8d
--- /dev/null
+++ b/main.go
@@ -0,0 +1,60 @@
+package main
+
+import (
+	"flag"
+	"log"
+
+	"go.eth.moe/catbus-actuator-wakeonlan/config"
+	"go.eth.moe/catbus-actuator-wakeonlan/mqtt"
+	"go.eth.moe/catbus-actuator-wakeonlan/wakeonlan"
+)
+
+var (
+	configPath = flag.String("config-path", "", "path to config")
+)
+
+func main() {
+	flag.Parse()
+
+	if *configPath == "" {
+		log.Fatal("must set -config-path")
+	}
+
+	config, err := config.ParseFile(*configPath)
+	if err != nil {
+		log.Fatalf("could not parse config file: %q", err)
+	}
+
+	brokerOptions := mqtt.NewClientOptions()
+	brokerOptions.AddBroker(config.Broker)
+	brokerOptions.SetAutoReconnect(true)
+	brokerOptions.SetConnectionLostHandler(func(_ mqtt.Client, err error) {
+		log.Printf("disconnected from MQTT broker %s: %v", config.Broker, err)
+	})
+	brokerOptions.SetOnConnectHandler(func(broker mqtt.Client) {
+		log.Printf("connected to MQTT broker %v", config.Broker)
+
+		for topic := range config.MACsByTopic {
+			token := broker.Subscribe(topic, mqtt.AtLeastOnce, func(_ mqtt.Client, msg mqtt.Message) {
+				mac, ok := config.MACsByTopic[msg.Topic()]
+				if !ok {
+					return
+				}
+				if err := wakeonlan.Wake(mac); err != nil {
+					log.Printf("could not send wake-on-lan: %v")
+				}
+			})
+			if err := token.Error(); err != nil {
+				log.Printf("could not subscribe to %q: %v", topic, err)
+
+			}
+		}
+	})
+
+	broker := mqtt.NewClient(brokerOptions)
+	if token := broker.Connect(); token.Error() != nil {
+		log.Fatalf("could not connect to MQTT broker: %v", token.Error())
+	}
+
+	select {}
+}
diff --git a/mqtt/mqtt.go b/mqtt/mqtt.go
new file mode 100644
index 0000000..7736049
--- /dev/null
+++ b/mqtt/mqtt.go
@@ -0,0 +1,29 @@
+// Package mqtt wraps Paho MQTT with a few quality-of-life features.
+package mqtt
+
+import (
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+type (
+	Client         = mqtt.Client
+	Message        = mqtt.Message
+	MessageHandler = mqtt.MessageHandler
+)
+
+const (
+	AtMostOnce byte = iota
+	AtLeastOnce
+	ExactlyOnce
+)
+
+const (
+	Retain = true
+)
+
+func NewClientOptions() *mqtt.ClientOptions {
+	return mqtt.NewClientOptions()
+}
+func NewClient(opts *mqtt.ClientOptions) mqtt.Client {
+	return mqtt.NewClient(opts)
+}
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))
+		}
+	}
+}