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linux-next/arch/um/Kconfig.net
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

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# SPDX-License-Identifier: GPL-2.0
menu "UML Network Devices"
depends on NET
# UML virtual driver
config UML_NET
bool "Virtual network device"
help
While the User-Mode port cannot directly talk to any physical
hardware devices, this choice and the following transport options
provide one or more virtual network devices through which the UML
kernels can talk to each other, the host, and with the host's help,
machines on the outside world.
For more information, including explanations of the networking and
sample configurations, see
<http://user-mode-linux.sourceforge.net/old/networking.html>.
If you'd like to be able to enable networking in the User-Mode
linux environment, say Y; otherwise say N. Note that you must
enable at least one of the following transport options to actually
make use of UML networking.
config UML_NET_ETHERTAP
bool "Ethertap transport"
depends on UML_NET
help
The Ethertap User-Mode Linux network transport allows a single
running UML to exchange packets with its host over one of the
host's Ethertap devices, such as /dev/tap0. Additional running
UMLs can use additional Ethertap devices, one per running UML.
While the UML believes it's on a (multi-device, broadcast) virtual
Ethernet network, it's in fact communicating over a point-to-point
link with the host.
To use this, your host kernel must have support for Ethertap
devices. Also, if your host kernel is 2.4.x, it must have
CONFIG_NETLINK_DEV configured as Y or M.
For more information, see
<http://user-mode-linux.sourceforge.net/old/networking.html> That site
has examples of the UML command line to use to enable Ethertap
networking.
If you'd like to set up an IP network with the host and/or the
outside world, say Y to this, the Daemon Transport and/or the
Slip Transport. You'll need at least one of them, but may choose
more than one without conflict. If you don't need UML networking,
say N.
config UML_NET_TUNTAP
bool "TUN/TAP transport"
depends on UML_NET
help
The UML TUN/TAP network transport allows a UML instance to exchange
packets with the host over a TUN/TAP device. This option will only
work with a 2.4 host, unless you've applied the TUN/TAP patch to
your 2.2 host kernel.
To use this transport, your host kernel must have support for TUN/TAP
devices, either built-in or as a module.
config UML_NET_SLIP
bool "SLIP transport"
depends on UML_NET
help
The slip User-Mode Linux network transport allows a running UML to
network with its host over a point-to-point link. Unlike Ethertap,
which can carry any Ethernet frame (and hence even non-IP packets),
the slip transport can only carry IP packets.
To use this, your host must support slip devices.
For more information, see
<http://user-mode-linux.sourceforge.net/old/networking.html>.
has examples of the UML command line to use to enable slip
networking, and details of a few quirks with it.
The Ethertap Transport is preferred over slip because of its
limitations. If you prefer slip, however, say Y here. Otherwise
choose the Multicast transport (to network multiple UMLs on
multiple hosts), Ethertap (to network with the host and the
outside world), and/or the Daemon transport (to network multiple
UMLs on a single host). You may choose more than one without
conflict. If you don't need UML networking, say N.
config UML_NET_DAEMON
bool "Daemon transport"
depends on UML_NET
help
This User-Mode Linux network transport allows one or more running
UMLs on a single host to communicate with each other, but not to
the host.
To use this form of networking, you'll need to run the UML
networking daemon on the host.
For more information, see
<http://user-mode-linux.sourceforge.net/old/networking.html> That site
has examples of the UML command line to use to enable Daemon
networking.
If you'd like to set up a network with other UMLs on a single host,
say Y. If you need a network between UMLs on multiple physical
hosts, choose the Multicast Transport. To set up a network with
the host and/or other IP machines, say Y to the Ethertap or Slip
transports. You'll need at least one of them, but may choose
more than one without conflict. If you don't need UML networking,
say N.
config UML_NET_VDE
bool "VDE transport"
depends on UML_NET
help
This User-Mode Linux network transport allows one or more running
UMLs on a single host to communicate with each other and also
with the rest of the world using Virtual Distributed Ethernet,
an improved fork of uml_switch.
You must have libvdeplug installed in order to build the vde
transport into UML.
To use this form of networking, you will need to run vde_switch
on the host.
For more information, see <http://wiki.virtualsquare.org/>
That site has a good overview of what VDE is and also examples
of the UML command line to use to enable VDE networking.
If you need UML networking with VDE,
say Y.
config UML_NET_MCAST
bool "Multicast transport"
depends on UML_NET
help
This Multicast User-Mode Linux network transport allows multiple
UMLs (even ones running on different host machines!) to talk to
each other over a virtual ethernet network. However, it requires
at least one UML with one of the other transports to act as a
bridge if any of them need to be able to talk to their hosts or any
other IP machines.
To use this, your host kernel(s) must support IP Multicasting.
For more information, see
<http://user-mode-linux.sourceforge.net/old/networking.html> That site
has examples of the UML command line to use to enable Multicast
networking, and notes about the security of this approach.
If you need UMLs on multiple physical hosts to communicate as if
they shared an Ethernet network, say Y. If you need to communicate
with other IP machines, make sure you select one of the other
transports (possibly in addition to Multicast; they're not
exclusive). If you don't need to network UMLs say N to each of
the transports.
config UML_NET_PCAP
bool "pcap transport"
depends on UML_NET
help
The pcap transport makes a pcap packet stream on the host look
like an ethernet device inside UML. This is useful for making
UML act as a network monitor for the host. You must have libcap
installed in order to build the pcap transport into UML.
For more information, see
<http://user-mode-linux.sourceforge.net/old/networking.html> That site
has examples of the UML command line to use to enable this option.
If you intend to use UML as a network monitor for the host, say
Y here. Otherwise, say N.
config UML_NET_SLIRP
bool "SLiRP transport"
depends on UML_NET
help
The SLiRP User-Mode Linux network transport allows a running UML
to network by invoking a program that can handle SLIP encapsulated
packets. This is commonly (but not limited to) the application
known as SLiRP, a program that can re-socket IP packets back onto
the host on which it is run. Only IP packets are supported,
unlike other network transports that can handle all Ethernet
frames. In general, slirp allows the UML the same IP connectivity
to the outside world that the host user is permitted, and unlike
other transports, SLiRP works without the need of root level
privleges, setuid binaries, or SLIP devices on the host. This
also means not every type of connection is possible, but most
situations can be accommodated with carefully crafted slirp
commands that can be passed along as part of the network device's
setup string. The effect of this transport on the UML is similar
that of a host behind a firewall that masquerades all network
connections passing through it (but is less secure).
To use this you should first have slirp compiled somewhere
accessible on the host, and have read its documentation. If you
don't need UML networking, say N.
Startup example: "eth0=slirp,FE:FD:01:02:03:04,/usr/local/bin/slirp"
endmenu