bpo-37085: Expose SocketCAN bcm_msg_head flags (#13646)

Expose the CAN_BCM SocketCAN constants used in the bcm_msg_head struct
flags (provided by <linux/can/bcm.h>) under the socket library.

This adds the following constants with a CAN_BCM prefix:

  * SETTIMER
  * STARTTIMER
  * TX_COUNTEVT
  * TX_ANNOUNCE
  * TX_CP_CAN_ID
  * RX_FILTER_ID
  * RX_CHECK_DLC
  * RX_NO_AUTOTIMER
  * RX_ANNOUNCE_RESUME
  * TX_RESET_MULTI_IDX
  * RX_RTR_FRAME
  * CAN_FD_FRAME

The CAN_FD_FRAME flag was introduced in the 4.8 kernel, while the other
ones were present since SocketCAN drivers were mainlined in 2.6.25. As
such, it is probably unnecessary to guard against these constants being
missing.

1 files changed, 13 insertions, 0 deletions

diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index 2705eff479..11b2a38ad7 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -1908,6 +1908,19 @@ class BasicCANTest(unittest.TestCase):
         socket.CAN_BCM_RX_TIMEOUT   # cyclic message is absent
         socket.CAN_BCM_RX_CHANGED   # updated CAN frame (detected content change)
 
+        # flags
+        socket.CAN_BCM_SETTIMER
+        socket.CAN_BCM_STARTTIMER
+        socket.CAN_BCM_TX_COUNTEVT
+        socket.CAN_BCM_TX_ANNOUNCE
+        socket.CAN_BCM_TX_CP_CAN_ID
+        socket.CAN_BCM_RX_FILTER_ID
+        socket.CAN_BCM_RX_CHECK_DLC
+        socket.CAN_BCM_RX_NO_AUTOTIMER
+        socket.CAN_BCM_RX_ANNOUNCE_RESUME
+        socket.CAN_BCM_TX_RESET_MULTI_IDX
+        socket.CAN_BCM_RX_RTR_FRAME
+
     def testCreateSocket(self):
         with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
             pass