1The DPDK uses the Open Source BSD-3-Clause license for the core libraries and 2drivers. The kernel components are naturally GPL-2.0 licensed. 3 4Including big blocks of License headers in all files blows up the 5source code with mostly redundant information. An additional problem 6is that even the same licenses are referred to by a number of 7slightly varying text blocks (full, abbreviated, different 8indentation, line wrapping and/or white space, with obsolete address 9information, ...) which makes validation and automatic processing a nightmare. 10 11To make this easier, DPDK uses a single line reference to Unique License 12Identifiers in source files as defined by the Linux Foundation's SPDX project 13(https://spdx.org/). 14 15Adding license information in this fashion, rather than adding full license 16text, can be more efficient for developers; decreases errors; and improves 17automated detection of licenses. The current set of valid, predefined SPDX 18identifiers is set forth on the SPDX License List at https://spdx.org/licenses/. 19 20DPDK uses first line of the file to be SPDX tag. In case of *#!* scripts, SPDX 21tag can be placed in 2nd line of the file. 22 23For example, to label a file as subject to the BSD-3-Clause license, 24the following text would be used: 25 26SPDX-License-Identifier: BSD-3-Clause 27 28To label a file as GPL-2.0 (e.g., for code that runs in the kernel), the 29following text would be used: 30 31SPDX-License-Identifier: GPL-2.0 32 33To label a file as dual-licensed with BSD-3-Clause and GPL-2.0 (e.g., for code 34that is shared between the kernel and userspace), the following text would be 35used: 36 37SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0) 38 39To label a file as dual-licensed with BSD-3-Clause and LGPL-2.1 (e.g., for code 40that is shared between the kernel and userspace), the following text would be 41used: 42 43SPDX-License-Identifier: (BSD-3-Clause OR LGPL-2.1) 44 45Any new file contributions in DPDK shall adhere to the above scheme. 46It is also being recommended to replace the existing license text in the code 47with SPDX-License-Identifiers. 48 49Any exception to the DPDK IP policies shall be approved by DPDK Tech Board and 50DPDK Governing Board. Steps for any exception approval: 511. Mention the appropriate license identifier form SPDX. If the license is not 52 listed in SPDX Licenses. It is the submitters responsibility to get it 53 first listed. 542. Get the required approval from the DPDK Technical Board. Technical Board may 55 advise the author to check alternate means first. If no other alternative 56 are found and the merit of the contributions are important for DPDK's 57 mission, it may decide on such exception with two-thirds vote of the members. 583. Technical Board then approach Governing Board for such limited approval for 59 the given contribution only. 60 61Any approvals shall be documented in "Licenses/exceptions.txt" with record 62dates. 63 64DPDK project supported licenses are: 65 661. BSD 3-clause "New" or "Revised" License 67 SPDX-License-Identifier: BSD-3-Clause 68 URL: http://spdx.org/licenses/BSD-3-Clause#licenseText 69 DPDK License text: licenses/bsd-3-clause.txt 702. GNU General Public License v2.0 only 71 SPDX-License-Identifier: GPL-2.0 72 URL: http://spdx.org/licenses/GPL-2.0.html#licenseText 73 DPDK License text: licenses/gpl-2.0.txt 743. GNU Lesser General Public License v2.1 75 SPDX-License-Identifier: LGPL-2.1 76 URL: http://spdx.org/licenses/LGPL-2.1.html#licenseText 77 DPDK License text: licenses/lgpl-2.1.txt 78