summaryrefslogtreecommitdiffstats
path: root/Documentation/networking/ipsec.rst
diff options
context:
space:
mode:
authorAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:12 +0200
committerAndi Shyti <andi.shyti@linux.intel.com>2026-08-22 14:19:34 +0200
commitd576a9561a1c80ae593539fb0ce0743d66825ac2 (patch)
tree68f6de7e06b350afa42edeea2f7f33f086014597 /Documentation/networking/ipsec.rst
downloadlinux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.tar.gz
linux-stable-d576a9561a1c80ae593539fb0ce0743d66825ac2.zip
Merge tag 'rust-i2c-for-7.3' into i2c/i2cgrafted
i2c: rust: mark I2cAdapter methods as inline A single cleanup for the Rust I2C abstractions, targeting 7.3. `I2cAdapter::get`, `inc_ref`, and `dec_ref` are trivial wrappers around `i2c_get_adapter`/`i2c_put_adapter` and were showing up as their own symbols in the build. Mark them `#[inline]` so they get folded into their callers instead. Signed-off-by: Igor Korotin <igor.korotin@linux.dev> * tag 'rust-i2c-for-7.3': i2c: rust: mark I2cAdapter methods as inline
Diffstat (limited to 'Documentation/networking/ipsec.rst')
-rw-r--r--Documentation/networking/ipsec.rst46
1 files changed, 46 insertions, 0 deletions
diff --git a/Documentation/networking/ipsec.rst b/Documentation/networking/ipsec.rst
new file mode 100644
index 000000000..afe9d7b48
--- /dev/null
+++ b/Documentation/networking/ipsec.rst
@@ -0,0 +1,46 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=====
+IPsec
+=====
+
+
+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.