docs: networking: convert ipsec.txt to ReST

Not much to be done here:

- add SPDX header;
- add a document title;
- adjust identation, whitespaces and blank lines;
- 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, 0 insertions, 38 deletions

diff --git a/Documentation/networking/ipsec.txt b/Documentation/networking/ipsec.txt
deleted file mode 100644
index ba794b7e51be..000000000000
--- a/Documentation/networking/ipsec.txt
+++ /dev/null
@@ -1,38 +0,0 @@
-
-Here documents known IPsec corner cases which need to be keep in mind when
-deploy various IPsec configuration in real world production environment.
-
-1. IPcomp: Small IP packet won't get compressed at sender, and failed on
-	   policy check on receiver.
-
-Quote from RFC3173:
-2.2. Non-Expansion Policy
-
-   If the total size of a compressed payload and the IPComp header, as
-   defined in section 3, is not smaller than the size of the original
-   payload, the IP datagram MUST be sent in the original non-compressed
-   form.  To clarify: If an IP datagram is sent non-compressed, no
-
-   IPComp header is added to the datagram.  This policy ensures saving
-   the decompression processing cycles and avoiding incurring IP
-   datagram fragmentation when the expanded datagram is larger than the
-   MTU.
-
-   Small IP datagrams are likely to expand as a result of compression.
-   Therefore, a numeric threshold should be applied before compression,
-   where IP datagrams of size smaller than the threshold are sent in the
-   original form without attempting compression.  The numeric threshold
-   is implementation dependent.
-
-Current IPComp implementation is indeed by the book, while as in practice
-when sending non-compressed packet to the peer (whether or not packet len
-is smaller than the threshold or the compressed len is larger than original
-packet len), the packet is dropped when checking the policy as this packet
-matches the selector but not coming from any XFRM layer, i.e., with no
-security path. Such naked packet will not eventually make it to upper layer.
-The result is much more wired to the user when ping peer with different
-payload length.
-
-One workaround is try to set "level use" for each policy if user observed
-above scenario. The consequence of doing so is small packet(uncompressed)
-will skip policy checking on receiver side.