1.. BSD LICENSE 2 Copyright(c) 2016 Intel Corporation. All rights reserved. 3 All rights reserved. 4 5 Redistribution and use in source and binary forms, with or without 6 modification, are permitted provided that the following conditions 7 are met: 8 9 * Redistributions of source code must retain the above copyright 10 notice, this list of conditions and the following disclaimer. 11 * Redistributions in binary form must reproduce the above copyright 12 notice, this list of conditions and the following disclaimer in 13 the documentation and/or other materials provided with the 14 distribution. 15 * Neither the name of Intel Corporation nor the names of its 16 contributors may be used to endorse or promote products derived 17 from this software without specific prior written permission. 18 19 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 20 "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 21 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 22 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 23 OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 24 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 25 LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 26 DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 27 THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 28 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 29 OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31.. _pdump_library: 32 33The librte_pdump Library 34======================== 35 36The ``librte_pdump`` library provides a framework for packet capturing in DPDK. 37The library does the complete copy of the Rx and Tx mbufs to a new mempool and 38hence it slows down the performance of the applications, so it is recommended 39to use this library for debugging purposes. 40 41The library provides the following APIs to initialize the packet capture framework, to enable 42or disable the packet capture, and to uninitialize it: 43 44* ``rte_pdump_init()``: 45 This API initializes the packet capture framework. 46 47* ``rte_pdump_enable()``: 48 This API enables the packet capture on a given port and queue. 49 Note: The filter option in the API is a place holder for future enhancements. 50 51* ``rte_pdump_enable_by_deviceid()``: 52 This API enables the packet capture on a given device id (``vdev name or pci address``) and queue. 53 Note: The filter option in the API is a place holder for future enhancements. 54 55* ``rte_pdump_disable()``: 56 This API disables the packet capture on a given port and queue. 57 58* ``rte_pdump_disable_by_deviceid()``: 59 This API disables the packet capture on a given device id (``vdev name or pci address``) and queue. 60 61* ``rte_pdump_uninit()``: 62 This API uninitializes the packet capture framework. 63 64* ``rte_pdump_set_socket_dir()``: 65 This API sets the server and client socket paths. 66 Note: This API is not thread-safe. 67 68 69Operation 70--------- 71 72The ``librte_pdump`` library works on a client/server model. The server is responsible for enabling or 73disabling the packet capture and the clients are responsible for requesting the enabling or disabling of 74the packet capture. 75 76The packet capture framework, as part of its initialization, creates the pthread and the server socket in 77the pthread. The application that calls the framework initialization will have the server socket created, 78either under the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for 79root user or ``~/.dpdk`` for non root user. 80 81Applications that request enabling or disabling of the packet capture will have the client socket created either under 82the path that the application has passed or under the default path i.e. either ``/var/run/.dpdk`` for root user or 83``~/.dpdk`` for not root user to send the requests to the server. The server socket will listen for client requests for 84enabling or disabling the packet capture. 85 86 87Implementation Details 88---------------------- 89 90The library API ``rte_pdump_init()``, initializes the packet capture framework by creating the pthread and the server 91socket. The server socket in the pthread context will be listening to the client requests to enable or disable the 92packet capture. 93 94The library APIs ``rte_pdump_enable()`` and ``rte_pdump_enable_by_deviceid()`` enables the packet capture. 95On each call to these APIs, the library creates a separate client socket, creates the "pdump enable" request and sends 96the request to the server. The server that is listening on the socket will take the request and enable the packet capture 97by registering the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. 98Then the server will mirror the packets to the new mempool and enqueue them to the rte_ring that clients have passed 99to these APIs. The server also sends the response back to the client about the status of the request that was processed. 100After the response is received from the server, the client socket is closed. 101 102The library APIs ``rte_pdump_disable()`` and ``rte_pdump_disable_by_deviceid()`` disables the packet capture. 103On each call to these APIs, the library creates a separate client socket, creates the "pdump disable" request and sends 104the request to the server. The server that is listening on the socket will take the request and disable the packet 105capture by removing the Ethernet RX and TX callbacks for the given port or device_id and queue combinations. The server 106also sends the response back to the client about the status of the request that was processed. After the response is 107received from the server, the client socket is closed. 108 109The library API ``rte_pdump_uninit()``, uninitializes the packet capture framework by closing the pthread and the 110server socket. 111 112The library API ``rte_pdump_set_socket_dir()``, sets the given path as either server socket path 113or client socket path based on the ``type`` argument of the API. 114If the given path is ``NULL``, default path will be selected, i.e. either ``/var/run/.dpdk`` for root user or ``~/.dpdk`` 115for non root user. Clients also need to call this API to set their server socket path if the server socket 116path is different from default path. 117 118 119Use Case: Packet Capturing 120-------------------------- 121 122The DPDK ``app/pdump`` tool is developed based on this library to capture packets in DPDK. 123Users can use this as an example to develop their own packet capturing tools. 124