daemon/ffi: skip layer calls in invalid states

daemon/ffimodule.c

@@ -165,6 +165,9 @@ static int l_ffi_layer_finish(knot_layer_t *ctx)
 
 static int l_ffi_layer_consume(knot_layer_t *ctx, knot_pkt_t *pkt)
 {
+	if (ctx->state & KNOT_STATE_FAIL) {
+		return ctx->state; /* Already failed, skip */
+	}
 	LAYER_FFI_CALL(ctx, "consume");
 	lua_pushlightuserdata(L, ctx->data);
 	lua_pushlightuserdata(L, pkt);
@@ -174,6 +177,9 @@ static int l_ffi_layer_consume(knot_layer_t *ctx, knot_pkt_t *pkt)
 
 static int l_ffi_layer_produce(knot_layer_t *ctx, knot_pkt_t *pkt)
 {
+	if (ctx->state & (KNOT_STATE_FAIL|KNOT_STATE_DONE)) {
+		return ctx->state; /* Already resolved/failed, skip */
+	}
 	LAYER_FFI_CALL(ctx, "produce");
 	lua_pushlightuserdata(L, ctx->data);
 	lua_pushlightuserdata(L, pkt);