Fix RouteGroup closing logic

pkg/router/route_group.go

@@ -80,10 +80,11 @@ type RouteGroup struct {
 	// 'readCh' reads in incoming packets of this route group.
 	// - Router should serve call '(*transport.Manager).ReadPacket' in a loop,
 	//      and push to the appropriate '(RouteGroup).readCh'.
-	readCh  chan []byte  // push reads from Router
-	readBuf bytes.Buffer // for read overflow
-	done    chan struct{}
-	once    sync.Once
+	readCh   chan []byte // push reads from Router
+	readChMu sync.Mutex
+	readBuf  bytes.Buffer // for read overflow
+	done     chan struct{}
+	once     sync.Once
 
 	readDeadline  deadline.PipeDeadline
 	writeDeadline deadline.PipeDeadline
@@ -256,7 +257,9 @@ func (r *RouteGroup) Close() error {
 
 	r.once.Do(func() {
 		close(r.done)
-		// close(r.readCh) // TODO(nkryuchkov): uncomment
+		r.readChMu.Lock()
+		close(r.readCh)
+		r.readChMu.Unlock()
 	})
 
 	return nil

pkg/router/route_group_test.go

@@ -465,12 +465,16 @@ func pushPackets(ctx context.Context, t *testing.T, from *transport.Manager, to
 				panic("malformed packet")
 			}
 
+			to.readChMu.Lock()
 			select {
 			case <-ctx.Done():
+				to.readChMu.Unlock()
 				return
 			case <-to.done:
+				to.readChMu.Unlock()
 				return
 			case to.readCh <- payload:
+				to.readChMu.Unlock()
 			}
 		}
 	}

pkg/router/routerclient/wrappers.go

@@ -12,7 +12,7 @@ import (
 	"github.com/SkycoinProject/skywire-mainnet/pkg/routing"
 )
 
-// TODO(nkryuchkov): remove this
+// TODO: remove this
 // dmsgClientWrapper is a temporary workaround to make dmsg client implement `snet.Dialer`.
 // The only reason to use this is because client's `Dial` returns `*dmsg.Stream` instead of `net.Conn`,
 // so this stuff should be removed as soon as the func's signature changes