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SPDX-License-Identifier: BSD-3-Clause 2 Copyright(c) 2016 Intel Corporation. 3 4.. _pdump_library: 5 6The librte_pdump Library 7======================== 8 9The ``librte_pdump`` library provides a framework for packet capturing in DPDK. 10The library does the complete copy of the Rx and Tx mbufs to a new mempool and 11hence it slows down the performance of the applications, so it is recommended 12to use this library for debugging purposes. 13 14The library provides the following APIs to initialize the packet capture framework, to enable 15or disable the packet capture, and to uninitialize it: 16 17* ``rte_pdump_init()``: 18 This API initializes the packet capture framework. 19 20* ``rte_pdump_enable()``: 21 This API enables the packet capture on a given port and queue. 22 Note: The filter option in the API is a place holder for future enhancements. 23 24* ``rte_pdump_enable_by_deviceid()``: 25 This API enables the packet capture on a given device id (``vdev name or pci address``) and queue. 26 Note: The filter option in the API is a place holder for future enhancements. 27 28* ``rte_pdump_disable()``: 29 This API disables the packet capture on a given port and queue. 30 31* ``rte_pdump_disable_by_deviceid()``: 32 This API disables the packet capture on a given device id (``vdev name or pci address``) and queue. 33 34* ``rte_pdump_uninit()``: 35 This API uninitializes the packet capture framework. 36 37* ``rte_pdump_set_socket_dir()``: 38 This API sets the server and client socket paths. 39 Note: This API is not thread-safe. 40 41 42Operation 43--------- 44 45The ``librte_pdump`` library works on a client/server model. The server is responsible for enabling or 46disabling the packet capture and the clients are responsible for requesting the enabling or disabling of 47the packet capture. 48 49The packet capture framework, as part of its initialization, creates the pthread and the server socket in 50the pthread. The application that calls the framework initialization will have the server socket created, 51either under the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for 52root user or ``~/.dpdk`` for non root user. 53 54Applications that request enabling or disabling of the packet capture will have the client socket created either under 55the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for root user or 56``~/.dpdk`` for not root user to send the requests to the server. The server socket will listen for client requests for 57enabling or disabling the packet capture. 58 59 60Implementation Details 61---------------------- 62 63The library API ``rte_pdump_init()``, initializes the packet capture framework by creating the pthread and the server 64socket. The server socket in the pthread context will be listening to the client requests to enable or disable the 65packet capture. 66 67The library APIs ``rte_pdump_enable()`` and ``rte_pdump_enable_by_deviceid()`` enables the packet capture. 68On each call to these APIs, the library creates a separate client socket, creates the "pdump enable" request and sends 69the request to the server. The server that is listening on the socket will take the request and enable the packet capture 70by registering the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. 71Then the server will mirror the packets to the new mempool and enqueue them to the rte_ring that clients have passed 72to these APIs. The server also sends the response back to the client about the status of the request that was processed. 73After the response is received from the server, the client socket is closed. 74 75The library APIs ``rte_pdump_disable()`` and ``rte_pdump_disable_by_deviceid()`` disables the packet capture. 76On each call to these APIs, the library creates a separate client socket, creates the "pdump disable" request and sends 77the request to the server. The server that is listening on the socket will take the request and disable the packet 78capture by removing the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. The server 79also sends the response back to the client about the status of the request that was processed. After the response is 80received from the server, the client socket is closed. 81 82The library API ``rte_pdump_uninit()``, uninitializes the packet capture framework by closing the pthread and the 83server socket. 84 85The library API ``rte_pdump_set_socket_dir()``, sets the given path as either server socket path 86or client socket path based on the ``type`` argument of the API. 87If the given path is ``NULL``, default path will be selected, i.e. either ``/var/run/.dpdk`` for root user or ``~/.dpdk`` 88for non root user. Clients also need to call this API to set their server socket path if the server socket 89path is different from default path. 90 91 92Use Case: Packet Capturing 93-------------------------- 94 95The DPDK ``app/pdump`` tool is developed based on this library to capture packets in DPDK. 96Users can use this as an example to develop their own packet capturing tools. 97