docs: networking: convert x25.txt to ReST

Not much to be done here:
- add SPDX header;
- add a document title;
- add to networking/index.rst.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 48 insertions, 0 deletions

diff --git a/Documentation/networking/x25.rst b/Documentation/networking/x25.rst
new file mode 100644
index 000000000000..00e45d384ba0
--- /dev/null
+++ b/Documentation/networking/x25.rst
@@ -0,0 +1,48 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+==================
+Linux X.25 Project
+==================
+
+As my third year dissertation at University I have taken it upon myself to
+write an X.25 implementation for Linux. My aim is to provide a complete X.25
+Packet Layer and a LAPB module to allow for "normal" X.25 to be run using
+Linux. There are two sorts of X.25 cards available, intelligent ones that
+implement LAPB on the card itself, and unintelligent ones that simply do
+framing, bit-stuffing and checksumming. These both need to be handled by the
+system.
+
+I therefore decided to write the implementation such that as far as the
+Packet Layer is concerned, the link layer was being performed by a lower
+layer of the Linux kernel and therefore it did not concern itself with
+implementation of LAPB. Therefore the LAPB modules would be called by
+unintelligent X.25 card drivers and not by intelligent ones, this would
+provide a uniform device driver interface, and simplify configuration.
+
+To confuse matters a little, an 802.2 LLC implementation for Linux is being
+written which will allow X.25 to be run over an Ethernet (or Token Ring) and
+conform with the JNT "Pink Book", this will have a different interface to
+the Packet Layer but there will be no confusion since the class of device
+being served by the LLC will be completely separate from LAPB. The LLC
+implementation is being done as part of another protocol project (SNA) and
+by a different author.
+
+Just when you thought that it could not become more confusing, another
+option appeared, XOT. This allows X.25 Packet Layer frames to operate over
+the Internet using TCP/IP as a reliable link layer. RFC1613 specifies the
+format and behaviour of the protocol. If time permits this option will also
+be actively considered.
+
+A linux-x25 mailing list has been created at vger.kernel.org to support the
+development and use of Linux X.25. It is early days yet, but interested
+parties are welcome to subscribe to it. Just send a message to
+majordomo@vger.kernel.org with the following in the message body:
+
+subscribe linux-x25
+end
+
+The contents of the Subject line are ignored.
+
+Jonathan
+
+g4klx@g4klx.demon.co.uk