1.. 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 38Operation 39--------- 40 41The ``librte_pdump`` library works on a client/server model. The server is responsible for enabling or 42disabling the packet capture and the clients are responsible for requesting the enabling or disabling of 43the packet capture. 44 45The packet capture framework, as part of its initialization, creates the pthread and the server socket in 46the pthread. The application that calls the framework initialization will have the server socket created, 47either under the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for 48root user or ``~/.dpdk`` for non root user. 49 50Applications that request enabling or disabling of the packet capture will have the client socket created either under 51the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for root user or 52``~/.dpdk`` for not root user to send the requests to the server. The server socket will listen for client requests for 53enabling or disabling the packet capture. 54 55 56Implementation Details 57---------------------- 58 59The library API ``rte_pdump_init()``, initializes the packet capture framework by creating the pdump server by calling 60``rte_mp_action_register()`` function. The server will listen to the client requests to enable or disable the 61packet capture. 62 63The library APIs ``rte_pdump_enable()`` and ``rte_pdump_enable_by_deviceid()`` enables the packet capture. 64On each call to these APIs, the library creates a separate client socket, creates the "pdump enable" request and sends 65the request to the server. The server that is listening on the socket will take the request and enable the packet capture 66by registering the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. 67Then the server will mirror the packets to the new mempool and enqueue them to the rte_ring that clients have passed 68to these APIs. The server also sends the response back to the client about the status of the request that was processed. 69After the response is received from the server, the client socket is closed. 70 71The library APIs ``rte_pdump_disable()`` and ``rte_pdump_disable_by_deviceid()`` disables the packet capture. 72On each call to these APIs, the library creates a separate client socket, creates the "pdump disable" request and sends 73the request to the server. The server that is listening on the socket will take the request and disable the packet 74capture by removing the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. The server 75also sends the response back to the client about the status of the request that was processed. After the response is 76received from the server, the client socket is closed. 77 78The library API ``rte_pdump_uninit()``, uninitializes the packet capture framework by calling ``rte_mp_action_unregister()`` 79function. 80 81 82Use Case: Packet Capturing 83-------------------------- 84 85The DPDK ``app/pdump`` tool is developed based on this library to capture packets in DPDK. 86Users can use this as an example to develop their own packet capturing tools. 87