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.
   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.
  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
  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/.
  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.
  23For example, to label a file as subject to the BSD-3-Clause license,
  24the following text would be used:
  26SPDX-License-Identifier: BSD-3-Clause
  28To label a file as GPL-2.0 (e.g., for code that runs in the kernel), the
  29following text would be used:
  31SPDX-License-Identifier: GPL-2.0
  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
  37SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0)
  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
  43SPDX-License-Identifier: (BSD-3-Clause OR LGPL-2.1)
  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.
  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.
  61Any approvals shall be documented in "Licenses/exceptions.txt" with record
  64DPDK project supported licenses are:
  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