diff --git a/internal/config/config.go b/internal/config/config.go
index e8a33dc..8df7058 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -23,6 +23,8 @@ import (
 var (
 	// ErrConfigNotFound is returned when a config file path is set but the file does not exist.
 	ErrConfigNotFound = errors.New("config file not found")
+	// ErrConfigInvalidUTF8 is returned when a config file is not valid UTF-8.
+	ErrConfigInvalidUTF8 = errors.New("config file is not valid UTF-8")
 	// ErrCryptoKeyConflict is returned when both inline and file-backed keys are configured.
 	ErrCryptoKeyConflict = errors.New("crypto.key and crypto.key_file cannot both be set")
 	// ErrCryptoKeyFileEmpty is returned when crypto.key_file points to an empty file.
@@ -178,7 +180,7 @@ func Load(path string) (File, error) {
 		return File{}, fmt.Errorf("read config %s: %w", path, err)
 	}
 	if !utf8.Valid(data) {
-		return File{}, fmt.Errorf("parse config %s: file is not valid UTF-8", path)
+		return File{}, fmt.Errorf("parse config %s: %w", path, ErrConfigInvalidUTF8)
 	}
 	var f File
 	if err := yaml.Unmarshal(data, &f); err != nil {
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index d72a978..062788b 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -4,7 +4,6 @@ import (
 	"errors"
 	"os"
 	"path/filepath"
-	"strings"
 	"testing"
 
 	"github.com/openlibrecommunity/olcrtc/internal/app/session"
@@ -329,7 +328,7 @@ func TestLoadInvalidUTF8(t *testing.T) {
 	}
 
 	_, err := Load(path)
-	if err == nil || !strings.Contains(err.Error(), "file is not valid UTF-8") {
+	if !errors.Is(err, ErrConfigInvalidUTF8) {
 		t.Fatalf("Load() error = %v, want invalid UTF-8 error", err)
 	}
 }
diff --git a/internal/control/control.go b/internal/control/control.go
index de4f521..450f340 100644
--- a/internal/control/control.go
+++ b/internal/control/control.go
@@ -164,38 +164,52 @@ func (s *state) readLoop(ctx context.Context) error {
 	for {
 		raw, err := readFrame(s.rw)
 		if err != nil {
-			if ctx.Err() != nil {
-				return fmt.Errorf("read loop canceled: %w", ctx.Err())
-			}
-			return err
+			return readLoopErr(ctx, err)
 		}
 		msg, err := parseMessage(raw)
 		if err != nil {
 			return err
 		}
-		switch msg.Type {
-		case TypePing:
-			if err := s.enqueue(ctx, Message{
-				Version:      ProtoVersion,
-				Type:         TypePong,
-				Seq:          msg.Seq,
-				SentUnixNano: msg.SentUnixNano,
-			}); err != nil {
-				if ctx.Err() != nil {
-					return fmt.Errorf("read loop canceled: %w", ctx.Err())
-				}
-				return err
-			}
-		case TypePong:
-			s.handlePong(msg)
-		case TypeClose:
-			return ErrClosedByPeer
-		default:
-			return fmt.Errorf("%w: got %q", ErrUnexpectedMessage, msg.Type)
+		if err := s.handleReadMessage(ctx, msg); err != nil {
+			return err
 		}
 	}
 }
 
+func readLoopErr(ctx context.Context, err error) error {
+	if ctx.Err() != nil {
+		return fmt.Errorf("read loop canceled: %w", ctx.Err())
+	}
+	return err
+}
+
+func (s *state) handleReadMessage(ctx context.Context, msg Message) error {
+	switch msg.Type {
+	case TypePing:
+		return s.enqueuePong(ctx, msg)
+	case TypePong:
+		s.handlePong(msg)
+		return nil
+	case TypeClose:
+		return ErrClosedByPeer
+	default:
+		return fmt.Errorf("%w: got %q", ErrUnexpectedMessage, msg.Type)
+	}
+}
+
+func (s *state) enqueuePong(ctx context.Context, ping Message) error {
+	err := s.enqueue(ctx, Message{
+		Version:      ProtoVersion,
+		Type:         TypePong,
+		Seq:          ping.Seq,
+		SentUnixNano: ping.SentUnixNano,
+	})
+	if err != nil {
+		return readLoopErr(ctx, err)
+	}
+	return nil
+}
+
 func (s *state) probeLoop(ctx context.Context) error {
 	ticker := time.NewTicker(s.cfg.Interval)
 	defer ticker.Stop()