Issue #15359: Add CAN_BCM protocol support to the socket module. Patch by Brian

Thorne.

Lib/test/test_socket.py

@@ -121,6 +121,36 @@ class SocketCANTest(unittest.TestCase):
     interface = 'vcan0'
     bufsize = 128
 
+    """The CAN frame structure is defined in <linux/can.h>:
+
+    struct can_frame {
+        canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
+        __u8    can_dlc; /* data length code: 0 .. 8 */
+        __u8    data[8] __attribute__((aligned(8)));
+    };
+    """
+    can_frame_fmt = "=IB3x8s"
+    can_frame_size = struct.calcsize(can_frame_fmt)
+
+    """The Broadcast Management Command frame structure is defined
+    in <linux/can/bcm.h>:
+
+    struct bcm_msg_head {
+        __u32 opcode;
+        __u32 flags;
+        __u32 count;
+        struct timeval ival1, ival2;
+        canid_t can_id;
+        __u32 nframes;
+        struct can_frame frames[0];
+    }
+
+    `bcm_msg_head` must be 8 bytes aligned because of the `frames` member (see
+    `struct can_frame` definition). Must use native not standard types for packing.
+    """
+    bcm_cmd_msg_fmt = "@3I4l2I"
+    bcm_cmd_msg_fmt += "x" * (struct.calcsize(bcm_cmd_msg_fmt) % 8)
+
     def setUp(self):
         self.s = socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW)
         self.addCleanup(self.s.close)
@@ -1291,10 +1321,35 @@ class BasicCANTest(unittest.TestCase):
         socket.PF_CAN
         socket.CAN_RAW
 
+    @unittest.skipUnless(hasattr(socket, "CAN_BCM"),
+                         'socket.CAN_BCM required for this test.')
+    def testBCMConstants(self):
+        socket.CAN_BCM
+
+        # opcodes
+        socket.CAN_BCM_TX_SETUP     # create (cyclic) transmission task
+        socket.CAN_BCM_TX_DELETE    # remove (cyclic) transmission task
+        socket.CAN_BCM_TX_READ      # read properties of (cyclic) transmission task
+        socket.CAN_BCM_TX_SEND      # send one CAN frame
+        socket.CAN_BCM_RX_SETUP     # create RX content filter subscription
+        socket.CAN_BCM_RX_DELETE    # remove RX content filter subscription
+        socket.CAN_BCM_RX_READ      # read properties of RX content filter subscription
+        socket.CAN_BCM_TX_STATUS    # reply to TX_READ request
+        socket.CAN_BCM_TX_EXPIRED   # notification on performed transmissions (count=0)
+        socket.CAN_BCM_RX_STATUS    # reply to RX_READ request
+        socket.CAN_BCM_RX_TIMEOUT   # cyclic message is absent
+        socket.CAN_BCM_RX_CHANGED   # updated CAN frame (detected content change)
+
     def testCreateSocket(self):
         with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
             pass
 
+    @unittest.skipUnless(hasattr(socket, "CAN_BCM"),
+                         'socket.CAN_BCM required for this test.')
+    def testCreateBCMSocket(self):
+        with socket.socket(socket.PF_CAN, socket.SOCK_DGRAM, socket.CAN_BCM) as s:
+            pass
+
     def testBindAny(self):
         with socket.socket(socket.PF_CAN, socket.SOCK_RAW, socket.CAN_RAW) as s:
             s.bind(('', ))
@@ -1327,19 +1382,8 @@ class BasicCANTest(unittest.TestCase):
 
 
 @unittest.skipUnless(HAVE_SOCKET_CAN, 'SocketCan required for this test.')
-@unittest.skipUnless(thread, 'Threading required for this test.')
 class CANTest(ThreadedCANSocketTest):
 
-    """The CAN frame structure is defined in <linux/can.h>:
-
-    struct can_frame {
-        canid_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
-        __u8    can_dlc; /* data length code: 0 .. 8 */
-        __u8    data[8] __attribute__((aligned(8)));
-    };
-    """
-    can_frame_fmt = "=IB3x8s"
-
     def __init__(self, methodName='runTest'):
         ThreadedCANSocketTest.__init__(self, methodName=methodName)
 
@@ -1388,6 +1432,46 @@ class CANTest(ThreadedCANSocketTest):
         self.cf2 = self.build_can_frame(0x12, b'\x99\x22\x33')
         self.cli.send(self.cf2)
 
+    @unittest.skipUnless(hasattr(socket, "CAN_BCM"),
+                         'socket.CAN_BCM required for this test.')
+    def _testBCM(self):
+        cf, addr = self.cli.recvfrom(self.bufsize)
+        self.assertEqual(self.cf, cf)
+        can_id, can_dlc, data = self.dissect_can_frame(cf)
+        self.assertEqual(self.can_id, can_id)
+        self.assertEqual(self.data, data)
+
+    @unittest.skipUnless(hasattr(socket, "CAN_BCM"),
+                         'socket.CAN_BCM required for this test.')
+    def testBCM(self):
+        bcm = socket.socket(socket.PF_CAN, socket.SOCK_DGRAM, socket.CAN_BCM)
+        self.addCleanup(bcm.close)
+        bcm.connect((self.interface,))
+        self.can_id = 0x123
+        self.data = bytes([0xc0, 0xff, 0xee])
+        self.cf = self.build_can_frame(self.can_id, self.data)
+        opcode = socket.CAN_BCM_TX_SEND
+        flags = 0
+        count = 0
+        ival1_seconds = ival1_usec = ival2_seconds = ival2_usec = 0
+        bcm_can_id = 0x0222
+        nframes = 1
+        assert len(self.cf) == 16
+        header = struct.pack(self.bcm_cmd_msg_fmt,
+                    opcode,
+                    flags,
+                    count,
+                    ival1_seconds,
+                    ival1_usec,
+                    ival2_seconds,
+                    ival2_usec,
+                    bcm_can_id,
+                    nframes,
+                    )
+        header_plus_frame = header + self.cf
+        bytes_sent = bcm.send(header_plus_frame)
+        self.assertEqual(bytes_sent, len(header_plus_frame))
+
 
 @unittest.skipUnless(HAVE_SOCKET_RDS, 'RDS sockets required for this test.')
 class BasicRDSTest(unittest.TestCase):