feat: support setting udp buffer size in run time

dlt/dlt.py

@@ -56,6 +56,9 @@
 DLT_EMPTY_FILE_ERROR = "DLT TRACE FILE IS EMPTY"
 cDLT_FILE_NOT_OPEN_ERROR = "Could not open DLT Trace file (libdlt)"  # pylint: disable=invalid-name
 
+DLT_UDP_MULTICAST_FD_BUFFER_SIZE = int(os.environ.get("PYDLT_UDP_MULTICAST_FD_BUFFER_SIZE", 2 * (2**20)))  # 2 Mb
+DLT_UDP_MULTICAST_BUFFER_SIZE = int(os.environ.get("PYDLT_UDP_MULTICAST_BUFFER_SIZE", 8 * (2**20)))  # 8 Mb
+
 
 class cached_property(object):  # pylint: disable=invalid-name
     """
@@ -865,13 +868,23 @@ def __len__(self):
 
 
 class DLTClient(cDltClient):
-    """DLTClient class takes care about correct initialization and
-    cleanup
-    """
+    """DLTClient class takes care about correct initialization and cleanup"""
 
     verbose = 0
 
     def __init__(self, **kwords):
+        """Initialize a DLTClient.
+
+        :param servIP: Optional[str] - dlt server IP.
+        :param hostIP: Optional[str] - Only available for udp multicast mode.
+            Set host interface address.
+        :param port: Optional[int] - dlt tcp daemon port.
+        :param verbose: Optional[bool] - Enable verbose output.
+        :param udp_fd_buffer_size_bytes: Optional[int] - Only available for udp
+            multicast mode. Set the UDP buffer size through setsockopt (unit: bytes).
+        :param udp_buffer_size_bytes: Optional[int] - Only available for udp
+            multicast mode. Set the DltReceiver's buffer size (unit: bytes).
+        """
         self.is_udp_multicast = False
         self.verbose = kwords.pop("verbose", 0)
         if dltlib.dlt_client_init(ctypes.byref(self), self.verbose) == DLT_RETURN_ERROR:
@@ -915,6 +928,9 @@ def __init__(self, **kwords):
         # it ourselves elsewhere
         self.port = kwords.get("port", DLT_DAEMON_TCP_PORT)
 
+        self._udp_fd_buffer_size_bytes = kwords.get("udp_fd_buffer_size_bytes", DLT_UDP_MULTICAST_FD_BUFFER_SIZE)
+        self._udp_buffer_size_bytes = kwords.get("udp_buffer_size_bytes", DLT_UDP_MULTICAST_BUFFER_SIZE)
+
     def connect(self, timeout=None):
         """Connect to the server
 
@@ -973,7 +989,9 @@ def connect(self, timeout=None):
         else:
             if self.verbose:
                 logger.info("Connecting DLTClient using UDP Connection")
+
             connected = dltlib.dlt_client_connect(ctypes.byref(self), self.verbose)
+            self._set_udp_multicast_buffer_size()
 
         if self.verbose:
             logger.info("DLT Connection return: %s", connected)
@@ -1051,6 +1069,54 @@ def client_loop(self):
         dltlib.dlt_client_register_message_callback(self.msg_callback)
         dltlib.dlt_client_main_loop(ctypes.byref(self), None, self.verbose)
 
+    def _set_udp_multicast_buffer_size(self, custom_fd_buffer_size_bytes=None, custom_buffer_size_bytes=None) -> None:
+        fd_buffer_size = int(self._udp_fd_buffer_size_bytes or custom_fd_buffer_size_bytes or 0)
+        buffer_size_bytes = int(self._udp_buffer_size_bytes or custom_buffer_size_bytes or 0)
+
+        if fd_buffer_size:
+            # Socket options are associated with an open file description. This
+            # means that file descriptors duplicated as a consequence of dup()
+            # (or similar) or fork() share the same set of socket options.
+            #     -- Chapter 61.9 Socket Options.
+            #        The Linux Programming Interface, p.1279
+            #
+            # The buffer size can be changed with a new fd which is created by
+            # dup system call (it's the internal implementation in
+            # `socket.fromfd`), so the code creates a socket instance first
+            # configures  it and directly close it.
+            with socket.fromfd(self.sock, socket.AF_INET, socket.SOCK_DGRAM) as conf_socket:
+                logger.debug("Set UDP Multicast socket buffer size: %s kbytes", fd_buffer_size / 1024)
+                conf_socket.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, fd_buffer_size)
+
+                real_buffer_size = int(conf_socket.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF) / 2)
+                if real_buffer_size != fd_buffer_size:
+                    logger.warning(
+                        (
+                            "Failed to set UDP Multicast buffer size. set_size: %s, real_size: %s. "
+                            "Bypass the error and continue"
+                        ),
+                        fd_buffer_size / 1024,
+                        real_buffer_size / 1024,
+                    )
+                    logger.warning(
+                        (
+                            "Please run command `sysctl -w net.core.rmem_max=%s` with root permission to "
+                            "set the maximum size and restart dlt again."
+                        ),
+                        fd_buffer_size,
+                    )
+
+        if buffer_size_bytes:
+            logger.debug("Set UDP Multicast DltReceiver buffer size: %s kbytes", buffer_size_bytes / 1024)
+            ret = dltlib.dlt_receiver_init(
+                ctypes.byref(self.receiver), self.sock, self.receiver.type, buffer_size_bytes
+            )
+            if ret < 0:
+                raise RuntimeError(
+                    f"Failed to set UDP Multicast DltReceiver buffer size. return code: {ret}, "
+                    f"buffer_size_bytes: {buffer_size_bytes}"
+                )
+
 
 def py_dlt_file_main_loop(dlt_reader, limit=None, callback=None):
     """Main loop to read dlt messages from dlt file."""

dlt/dlt_broker_handlers.py

@@ -15,6 +15,8 @@
 from dlt.dlt import (
     DLTClient,
     DLT_DAEMON_TCP_PORT,
+    DLT_UDP_MULTICAST_BUFFER_SIZE,
+    DLT_UDP_MULTICAST_FD_BUFFER_SIZE,
     cDLT_FILE_NOT_OPEN_ERROR,
     load,
     py_dlt_client_main_loop,
@@ -402,6 +404,8 @@ def __init__(
         self.tracefile = None
         self.last_connected = time.time()
         self.last_message = time.time() - 120.0
+        self._udp_fd_buffer_size_bytes = client_cfg.get("udp_fd_buffer_size_bytes", DLT_UDP_MULTICAST_FD_BUFFER_SIZE)
+        self._udp_buffer_size_bytes = client_cfg.get("udp_buffer_size_bytes", DLT_UDP_MULTICAST_BUFFER_SIZE)
 
     def is_valid_message(self, message):
         return message and (message.apid != "" or message.ctid != "")
@@ -420,7 +424,13 @@ def _client_connect(self):
                 self._port,
                 self._filename,
             )
-        self._client = DLTClient(servIP=self._ip_address, port=self._port, verbose=self.verbose)
+        self._client = DLTClient(
+            servIP=self._ip_address,
+            port=self._port,
+            verbose=self.verbose,
+            udp_fd_buffer_size_bytes=self._udp_fd_buffer_size_bytes,
+            udp_buffer_size_bytes=self._udp_buffer_size_bytes,
+        )
         connected = self._client.connect(self.timeout)
         if connected:
             logger.info("DLTClient connected to %s", self._client.servIP)

dlt/py_dlt_receive.py

@@ -5,6 +5,7 @@
 import logging
 import time
 
+from dlt.dlt import DLT_UDP_MULTICAST_FD_BUFFER_SIZE, DLT_UDP_MULTICAST_BUFFER_SIZE
 from dlt.dlt_broker import DLTBroker
 
 logging.basicConfig(format="%(asctime)s %(name)s %(levelname)-8s %(message)s")
@@ -18,13 +19,32 @@ def parse_args():
     parser = argparse.ArgumentParser(description="Receive DLT messages")
     parser.add_argument("--host", required=True, help="hostname or ip address to connect to")
     parser.add_argument("--file", required=True, help="The file into which the messages will be written")
+    parser.add_argument(
+        "--udp-fd-buffer-size",
+        dest="udp_fd_buffer_size",
+        default=DLT_UDP_MULTICAST_FD_BUFFER_SIZE,
+        type=int,
+        help=f"Set the socket buffer size in udp multicast mode. default: {DLT_UDP_MULTICAST_FD_BUFFER_SIZE} bytes",
+    )
+    parser.add_argument(
+        "--udp-buffer-size",
+        dest="udp_buffer_size",
+        default=DLT_UDP_MULTICAST_BUFFER_SIZE,
+        type=int,
+        help=f"Set the DltReceiver buffer size in udp multicast mode. default: {DLT_UDP_MULTICAST_BUFFER_SIZE} bytes",
+    )
     return parser.parse_args()
 
 
 def dlt_receive(options):
     """Receive DLT messages via DLTBroker"""
     logger.info("Creating DLTBroker instance")
-    broker = DLTBroker(ip_address=options.host, filename=options.file)
+    broker = DLTBroker(
+        ip_address=options.host,
+        filename=options.file,
+        udp_fd_buffer_size_bytes=options.udp_buffer_size,
+        udp_buffer_size_bytes=options.udp_fd_buffer_size,
+    )
 
     logger.info("Starting DLTBroker")
     broker.start()  # start the loop