PbReader fix: audio packets from anonymous users results in panic (#37)

For each user an Audio Codec is created on the fly with the first
received packet. The Protobuf Message contains a UserID field
which should be set by the client. The UserID is used to ensure
that the audio frames are correcty decoded and that simultaneously
received packets from multiple users are not mixed.
In case a packet with an empty UserID is received, the userID
will be set to 'unknown-client' and a warning is logged.

Author: Tobias Wellnitz, DH1TW

.github/workflows/build.yml

@@ -54,11 +54,11 @@ jobs:
             OS: darwin
             ARCH: arm64
     steps:
-    - name: Set up Go 1.17
+    - name: Set up Go 1.18
       uses: actions/setup-go@v1
       id: go
       with:
-        go-version: 1.17
+        go-version: 1.18
     - uses: actions/checkout@v1
       with:
         submodules: true

audio/sinks/pbWriter/pbWriter.go

@@ -9,6 +9,7 @@ import (
 	"github.com/dh1tw/gosamplerate"
 	"github.com/dh1tw/remoteAudio/audio"
 	"github.com/dh1tw/remoteAudio/audiocodec/opus"
+	"github.com/dh1tw/remoteAudio/utils"
 	"github.com/golang/protobuf/proto"
 
 	sbAudio "github.com/dh1tw/remoteAudio/sb_audio"
@@ -45,7 +46,7 @@ func NewPbWriter(opts ...Option) (*PbWriter, error) {
 			DeviceName:      "ProtoBufWriter",
 			Channels:        1,
 			FramesPerBuffer: 960,
-			UserID:          "myCallsign",
+			UserID:          fmt.Sprintf("user-%s", utils.RandStringRunes(5)),
 		},
 		buffer: make([]byte, 10000),
 		volume: 0.7,

audio/sources/pbReader/pbReader.go

@@ -17,12 +17,13 @@ import (
 // received from the network.
 type PbReader struct {
 	sync.RWMutex
-	enabled  bool
-	name     string
-	decoders map[string]audiocodec.Decoder
-	decoder  audiocodec.Decoder
-	callback audio.OnDataCb
-	lastUser string
+	enabled            bool
+	name               string
+	decoders           map[string]audiocodec.Decoder
+	decoder            audiocodec.Decoder
+	callback           audio.OnDataCb
+	lastUser           string
+	emptyUserIDWarning sync.Once
 }
 
 // NewPbReader is the constructor for a PbReader object.
@@ -104,6 +105,14 @@ func (pbr *PbReader) Enqueue(data []byte) error {
 		return nil
 	}
 
+	if len(msg.GetUserId()) == 0 {
+		msg.UserId = "unknown-client"
+		pbr.emptyUserIDWarning.Do(func() {
+			log.Println("incoming audio frames from unknown user; consider setting the username on the client")
+			log.Println("simultaneous audio frames from multiple anonymous users will result in distorted audio")
+		})
+	}
+
 	codecName := msg.GetCodec().String()
 
 	switch codecName {
@@ -141,6 +150,10 @@ func (pbr *PbReader) Enqueue(data []byte) error {
 		pbr.lastUser = txUser
 	}
 
+	if pbr.decoder == nil {
+		return fmt.Errorf("no decoder set for audio frames from user: '%s'", txUser)
+	}
+
 	num, err := pbr.decoder.Decode(msg.Data, buf)
 	if err != nil {
 		// in case the txUser has switched from stereo to mono

cmd/client_nats.go

@@ -25,6 +25,7 @@ import (
 	"github.com/dh1tw/remoteAudio/audiocodec/opus"
 	"github.com/dh1tw/remoteAudio/proxy"
 	"github.com/dh1tw/remoteAudio/trx"
+	"github.com/dh1tw/remoteAudio/utils"
 	"github.com/dh1tw/remoteAudio/webserver"
 	"github.com/gordonklaus/portaudio"
 	"github.com/nats-io/nats.go"
@@ -253,11 +254,17 @@ func natsAudioClient(cmd *cobra.Command, args []string) {
 		exit(err)
 	}
 
+	userName := natsUsername
+	if len(userName) == 0 {
+		userName = fmt.Sprintf("client-%s", utils.RandStringRunes(5))
+		log.Printf("username not set; auto generated unique username '%s'\n", userName)
+	}
+
 	toNetwork, err := pbWriter.NewPbWriter(
 		pbWriter.Encoder(opusEncoder),
 		pbWriter.Channels(iChannels),
 		pbWriter.FramesPerBuffer(audioFramesPerBuffer),
-		pbWriter.UserID(natsUsername),
+		pbWriter.UserID(userName),
 	)
 	if err != nil {
 		exit(err)

cmd/server_nats.go

@@ -269,6 +269,7 @@ func natsAudioServer(cmd *cobra.Command, args []string) {
 		pbWriter.Channels(iChannels),
 		pbWriter.FramesPerBuffer(audioFramesPerBuffer),
 		pbWriter.ToWireCb(ns.toWireCb),
+		pbWriter.UserID(serverName),
 	)
 	if err != nil {
 		exit(err)

go.mod

@@ -14,12 +14,16 @@ require (
 	github.com/go-audio/audio v1.0.0
 	github.com/go-audio/wav v1.0.0
 	github.com/golang/protobuf v1.5.2
-	github.com/gordonklaus/portaudio v0.0.0-20200911161147-bb74aa485641
+	github.com/gordonklaus/portaudio v0.0.0-20220320131553-cc649ad523c1
 	github.com/gorilla/mux v1.8.0
-	github.com/gorilla/websocket v1.4.2
+	github.com/gorilla/websocket v1.5.0
+	github.com/magiconair/properties v1.8.6 // indirect
 	github.com/nats-io/nats.go v1.13.0
-	github.com/spf13/cobra v1.2.1
-	github.com/spf13/viper v1.10.0
-	google.golang.org/protobuf v1.27.1
-	gopkg.in/hraban/opus.v2 v2.0.0-20211030232353-1a9beeaf0764
+	github.com/spf13/afero v1.8.2 // indirect
+	github.com/spf13/cobra v1.4.0
+	github.com/spf13/viper v1.10.1
+	golang.org/x/sys v0.0.0-20220403205710-6acee93ad0eb // indirect
+	google.golang.org/protobuf v1.28.0
+	gopkg.in/hraban/opus.v2 v2.0.0-20220302220929-eeacdbcb92d0
+	gopkg.in/ini.v1 v1.66.4 // indirect
 )