Ability to send HCI commands from Rust

* Autogenerate packet code in Rust from PDL (packet file copied from rootcanal)
* Implement parsing of packets that have a type header
* Expose Python APIs for sending HCI commands
* Expose Python APIs for instantiating a local controller

rust/src/wrapper/controller.rs

@@ -0,0 +1,62 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+//! Controller components
+use crate::wrapper::{
+    common::{TransportSink, TransportSource},
+    hci::Address,
+    link::Link,
+    PyDictExt,
+};
+use pyo3::{
+    intern,
+    types::{PyDict, PyModule},
+    PyObject, PyResult, Python,
+};
+use pyo3_asyncio::tokio::into_future;
+
+/// A controller that can send and receive HCI frames via some link
+#[derive(Clone)]
+pub struct Controller(pub(crate) PyObject);
+
+impl Controller {
+    /// Creates a new [Controller] object. When optional arguments are not specified, the Python
+    /// module specifies the defaults. Must be called from a thread with a Python event loop, which
+    /// should be true on `tokio::main` and `async_std::main`.
+    ///
+    /// For more info, see https://awestlake87.github.io/pyo3-asyncio/master/doc/pyo3_asyncio/#event-loop-references-and-contextvars.
+    pub async fn new(
+        name: &str,
+        host_source: Option<TransportSource>,
+        host_sink: Option<TransportSink>,
+        link: Option<Link>,
+        public_address: Option<Address>,
+    ) -> PyResult<Self> {
+        Python::with_gil(|py| {
+            let kwargs = PyDict::new(py);
+            kwargs.set_item("name", name)?;
+            kwargs.set_opt_item("host_source", host_source)?;
+            kwargs.set_opt_item("host_sink", host_sink)?;
+            kwargs.set_opt_item("link", link)?;
+            kwargs.set_opt_item("public_address", public_address)?;
+
+            PyModule::import(py, intern!(py, "bumble.controller"))?
+                .getattr(intern!(py, "Controller"))?
+                .call_method("create", (), Some(kwargs))
+                .and_then(into_future)
+        })?
+        .await
+        .map(Self)
+    }
+}