CAN fingerprinting: count empty CAN packets as frames (#33232)

* content of can packet won't affect can fingerprint time

* remove get_one_can

* fix comment

* actually we still want to be able to send empty can (xx fingerprint func does this if it runs out of msgs)

* fix process replay
old-commit-hash: 87f183f43c

selfdrive/car/car_helpers.py

@@ -15,13 +15,6 @@ from openpilot.selfdrive.car import gen_empty_fingerprint
 FRAME_FINGERPRINT = 100  # 1s
 
 
-def get_one_can(logcan):
-  while True:
-    can = messaging.recv_one_retry(logcan)
-    if len(can.can) > 0:
-      return can
-
-
 def load_interfaces(brand_names):
   ret = {}
   for brand_name in brand_names:
@@ -48,7 +41,7 @@ interface_names = _get_interface_names()
 interfaces = load_interfaces(interface_names)
 
 
-def can_fingerprint(next_can: Callable) -> tuple[str | None, dict[int, dict]]:
+def can_fingerprint(can_recv: Callable) -> tuple[str | None, dict[int, dict]]:
   finger = gen_empty_fingerprint()
   candidate_cars = {i: all_legacy_fingerprint_cars() for i in [0, 1]}  # attempt fingerprint on both bus 0 and 1
   frame = 0
@@ -56,34 +49,35 @@ def can_fingerprint(next_can: Callable) -> tuple[str | None, dict[int, dict]]:
   done = False
 
   while not done:
-    a = next_can()
-
-    for can in a.can:
-      # The fingerprint dict is generated for all buses, this way the car interface
-      # can use it to detect a (valid) multipanda setup and initialize accordingly
-      if can.src < 128:
-        if can.src not in finger:
-          finger[can.src] = {}
-        finger[can.src][can.address] = len(can.dat)
-
+    # can_recv() may return zero or multiple packets, so we increment frame for each one we receive
+    can_packets = can_recv()
+    for can_packet in can_packets:
+      for can in can_packet.can:
+        # The fingerprint dict is generated for all buses, this way the car interface
+        # can use it to detect a (valid) multipanda setup and initialize accordingly
+        if can.src < 128:
+          if can.src not in finger:
+            finger[can.src] = {}
+          finger[can.src][can.address] = len(can.dat)
+
+        for b in candidate_cars:
+          # Ignore extended messages and VIN query response.
+          if can.src == b and can.address < 0x800 and can.address not in (0x7df, 0x7e0, 0x7e8):
+            candidate_cars[b] = eliminate_incompatible_cars(can, candidate_cars[b])
+
+      # if we only have one car choice and the time since we got our first
+      # message has elapsed, exit
       for b in candidate_cars:
-        # Ignore extended messages and VIN query response.
-        if can.src == b and can.address < 0x800 and can.address not in (0x7df, 0x7e0, 0x7e8):
-          candidate_cars[b] = eliminate_incompatible_cars(can, candidate_cars[b])
-
-    # if we only have one car choice and the time since we got our first
-    # message has elapsed, exit
-    for b in candidate_cars:
-      if len(candidate_cars[b]) == 1 and frame > FRAME_FINGERPRINT:
-        # fingerprint done
-        car_fingerprint = candidate_cars[b][0]
+        if len(candidate_cars[b]) == 1 and frame > FRAME_FINGERPRINT:
+          # fingerprint done
+          car_fingerprint = candidate_cars[b][0]
 
-    # bail if no cars left or we've been waiting for more than 2s
-    failed = (all(len(cc) == 0 for cc in candidate_cars.values()) and frame > FRAME_FINGERPRINT) or frame > 200
-    succeeded = car_fingerprint is not None
-    done = failed or succeeded
+      # bail if no cars left or we've been waiting for more than 2s
+      failed = (all(len(cc) == 0 for cc in candidate_cars.values()) and frame > FRAME_FINGERPRINT) or frame > 200
+      succeeded = car_fingerprint is not None
+      done = failed or succeeded
 
-    frame += 1
+      frame += 1
 
   return car_fingerprint, finger
 
@@ -139,7 +133,7 @@ def fingerprint(logcan, sendcan, set_obd_multiplexing, num_pandas, cached_params
   # CAN fingerprint
   # drain CAN socket so we get the latest messages
   messaging.drain_sock_raw(logcan)
-  car_fingerprint, finger = can_fingerprint(lambda: get_one_can(logcan))
+  car_fingerprint, finger = can_fingerprint(lambda: messaging.drain_sock(logcan, wait_for_one=True))
 
   exact_match = True
   source = car.CarParams.FingerprintSource.can

selfdrive/car/card.py

@@ -14,7 +14,7 @@ from openpilot.common.swaglog import cloudlog, ForwardingHandler
 
 from openpilot.selfdrive.pandad import can_capnp_to_list, can_list_to_can_capnp
 from openpilot.selfdrive.car import DT_CTRL, carlog
-from openpilot.selfdrive.car.car_helpers import get_car, get_one_can
+from openpilot.selfdrive.car.car_helpers import get_car
 from openpilot.selfdrive.car.interfaces import CarInterfaceBase
 from openpilot.selfdrive.controls.lib.events import Events
 
@@ -58,7 +58,10 @@ class Car:
     if CI is None:
       # wait for one pandaState and one CAN packet
       print("Waiting for CAN messages...")
-      get_one_can(self.can_sock)
+      while True:
+        can = messaging.recv_one_retry(self.can_sock)
+        if len(can.can) > 0:
+          break
 
       experimental_long_allowed = self.params.get_bool("ExperimentalLongitudinalEnabled")
       num_pandas = len(messaging.recv_one_retry(self.sm.sock['pandaStates']).pandaStates)

selfdrive/car/tests/test_can_fingerprint.py

@@ -17,7 +17,7 @@ class TestCanFingerprint:
 
       fingerprint_iter = iter([can])
       empty_can = messaging.new_message('can', 0)
-      car_fingerprint, finger = can_fingerprint(lambda: next(fingerprint_iter, empty_can))  # noqa: B023
+      car_fingerprint, finger = can_fingerprint(lambda: [next(fingerprint_iter, empty_can)])  # noqa: B023
 
       assert car_fingerprint == car_model
       assert finger[0] == fingerprint
@@ -54,8 +54,8 @@ class TestCanFingerprint:
         def test():
           nonlocal frames
           frames += 1
-          return can  # noqa: B023
+          return [can]  # noqa: B023
 
         car_fingerprint, _ = can_fingerprint(test)
         assert car_fingerprint == car_model
-        assert frames == expected_frames + 2# TODO: fix extra frames
+        assert frames == expected_frames + 2  # TODO: fix extra frames

selfdrive/test/process_replay/process_replay.py

@@ -335,7 +335,7 @@ def card_fingerprint_callback(rc, pm, msgs, fingerprint):
 
     m = canmsgs.pop(0)
     rc.send_sync(pm, "can", m.as_builder().to_bytes())
-    rc.wait_for_next_recv(False)
+    rc.wait_for_next_recv(True)
 
 
 def get_car_params_callback(rc, pm, msgs, fingerprint):