bridge: support bridge 2.0.25+

which can do read/write separately and supports debuglink

trezorlib/transport/bridge.py

@@ -29,6 +29,8 @@ LOG = logging.getLogger(__name__)
 TREZORD_HOST = "http://127.0.0.1:21325"
 TREZORD_ORIGIN_HEADER = {"Origin": "https://python.trezor.io"}
 
+TREZORD_VERSION_MODERN = (2, 0, 25)
+
 CONNECTION = requests.Session()
 CONNECTION.headers.update(TREZORD_ORIGIN_HEADER)
 
@@ -44,6 +46,52 @@ def call_bridge(uri: str, data=None) -> requests.Response:
     return r
 
 
+def is_legacy_bridge() -> bool:
+    config = call_bridge("configure").json()
+    version_tuple = tuple(map(int, config["version"].split(".")))
+    return version_tuple < TREZORD_VERSION_MODERN
+
+
+class BridgeHandle:
+    def __init__(self, transport: "BridgeTransport") -> None:
+        self.transport = transport
+
+    def read_buf(self) -> bytes:
+        raise NotImplementedError
+
+    def write_buf(self, buf: bytes) -> None:
+        raise NotImplementedError
+
+
+class BridgeHandleModern(BridgeHandle):
+    def write_buf(self, buf: bytes) -> None:
+        self.transport._call("post", data=buf.hex())
+
+    def read_buf(self) -> bytes:
+        data = self.transport._call("read")
+        return bytes.fromhex(data.text)
+
+
+class BridgeHandleLegacy(BridgeHandle):
+    def __init__(self, transport: "BridgeTransport") -> None:
+        super().__init__(transport)
+        self.request = None  # type: Optional[str]
+
+    def write_buf(self, buf: bytes) -> None:
+        if self.request is not None:
+            raise TransportException("Can't write twice on legacy Bridge")
+        self.request = buf.hex()
+
+    def read_buf(self) -> bytes:
+        if self.request is None:
+            raise TransportException("Can't read without write on legacy Bridge")
+        try:
+            data = self.transport._call("call", data=self.request)
+            return bytes.fromhex(data.text)
+        finally:
+            self.request = None
+
+
 class BridgeTransport(Transport):
     """
     BridgeTransport implements transport through TREZOR Bridge (aka trezord).
@@ -51,44 +99,58 @@ class BridgeTransport(Transport):
 
     PATH_PREFIX = "bridge"
 
-    def __init__(self, device: Dict[str, Any]) -> None:
+    def __init__(
+        self, device: Dict[str, Any], legacy: bool, debug: bool = False
+    ) -> None:
+        if legacy and debug:
+            raise TransportException("Debugging not supported on legacy Bridge")
+
         self.device = device
         self.session = None  # type: Optional[str]
-        self.request = None  # type: Optional[str]
-        self.debug = False
+        self.debug = debug
+        self.legacy = legacy
+
+        if legacy:
+            self.handle = BridgeHandleLegacy(self)  # type: BridgeHandle
+        else:
+            self.handle = BridgeHandleModern(self)
 
     def get_path(self) -> str:
         return "%s:%s" % (self.PATH_PREFIX, self.device["path"])
 
-    @classmethod
-    def enumerate(cls) -> Iterable["BridgeTransport"]:
-        try:
-            return [BridgeTransport(dev) for dev in call_bridge("enumerate").json()]
-        except Exception:
-            return []
+    def find_debug(self) -> "BridgeTransport":
+        if not self.device.get("debug"):
+            raise TransportException("Debug device not available")
+        return BridgeTransport(self.device, self.legacy, debug=True)
 
     def _call(self, action: str, data: str = None) -> requests.Response:
         session = self.session or "null"
         uri = action + "/" + str(session)
+        if self.debug:
+            uri = "debug/" + uri
         return call_bridge(uri, data=data)
 
+    @classmethod
+    def enumerate(cls) -> Iterable["BridgeTransport"]:
+        try:
+            legacy = is_legacy_bridge()
+            return [
+                BridgeTransport(dev, legacy) for dev in call_bridge("enumerate").json()
+            ]
+        except Exception:
+            return []
+
     def begin_session(self) -> None:
-        LOG.debug("acquiring session from {}".format(self.session))
         data = self._call("acquire/" + self.device["path"])
         self.session = data.json()["session"]
-        LOG.debug("acquired session {}".format(self.session))
 
     def end_session(self) -> None:
-        LOG.debug("releasing session {}".format(self.session))
         if not self.session:
             return
         self._call("release")
         self.session = None
 
     def write(self, msg: protobuf.MessageType) -> None:
-        if self.request is not None:
-            raise TransportException("Cannot enqueue two requests")
-
         LOG.debug(
             "sending message: {}".format(msg.__class__.__name__),
             extra={"protobuf": msg},
@@ -98,25 +160,19 @@ class BridgeTransport(Transport):
         ser = buffer.getvalue()
         header = struct.pack(">HL", mapping.get_type(msg), len(ser))
 
-        self.request = (header + ser).hex()
+        self.handle.write_buf(header + ser)
 
     def read(self) -> protobuf.MessageType:
-        if self.request is None:
-            raise TransportException("No request stored")
-
-        try:
-            data = bytes.fromhex(self._call("call", data=self.request).text)
-            headerlen = struct.calcsize(">HL")
-            msg_type, datalen = struct.unpack(">HL", data[:headerlen])
-            buffer = BytesIO(data[headerlen : headerlen + datalen])
-            msg = protobuf.load_message(buffer, mapping.get_class(msg_type))
-            LOG.debug(
-                "received message: {}".format(msg.__class__.__name__),
-                extra={"protobuf": msg},
-            )
-            return msg
-        finally:
-            self.request = None
+        data = self.handle.read_buf()
+        headerlen = struct.calcsize(">HL")
+        msg_type, datalen = struct.unpack(">HL", data[:headerlen])
+        buffer = BytesIO(data[headerlen : headerlen + datalen])
+        msg = protobuf.load_message(buffer, mapping.get_class(msg_type))
+        LOG.debug(
+            "received message: {}".format(msg.__class__.__name__),
+            extra={"protobuf": msg},
+        )
+        return msg
 
 
 TRANSPORT = BridgeTransport