From 4352b8aee98005853aa63f57d6377282de17a33f Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 23 Aug 2026 13:28:57 -0700 Subject: Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ... --- Documentation/networking/ipsec.rst | 46 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 Documentation/networking/ipsec.rst (limited to 'Documentation/networking/ipsec.rst') 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. -- cgit v1.3.1