linux-yocto/Documentation
Matthieu Baerts (NGI0) c839be6df4 mptcp: pm: nl: announce deny-join-id0 flag
commit 2293c57484ae64c9a3c847c8807db8c26a3a4d41 upstream.

During the connection establishment, a peer can tell the other one that
it cannot establish new subflows to the initial IP address and port by
setting the 'C' flag [1]. Doing so makes sense when the sender is behind
a strict NAT, operating behind a legacy Layer 4 load balancer, or using
anycast IP address for example.

When this 'C' flag is set, the path-managers must then not try to
establish new subflows to the other peer's initial IP address and port.
The in-kernel PM has access to this info, but the userspace PM didn't.

The RFC8684 [1] is strict about that:

  (...) therefore the receiver MUST NOT try to open any additional
  subflows toward this address and port.

So it is important to tell the userspace about that as it is responsible
for the respect of this flag.

When a new connection is created and established, the Netlink events
now contain the existing but not currently used 'flags' attribute. When
MPTCP_PM_EV_FLAG_DENY_JOIN_ID0 is set, it means no other subflows
to the initial IP address and port -- info that are also part of the
event -- can be established.

Link: https://datatracker.ietf.org/doc/html/rfc8684#section-3.1-20.6 [1]
Fixes: 702c2f646d ("mptcp: netlink: allow userspace-driven subflow establishment")
Reported-by: Marek Majkowski <marek@cloudflare.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/532
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20250912-net-mptcp-pm-uspace-deny_join_id0-v1-2-40171884ade8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ Conflicts in mptcp_pm.yaml, because the indentation has been modified
  in commit ec362192aa ("netlink: specs: fix up indentation errors"),
  which is not in this version. Applying the same modifications, but at
  a different level. ]
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-09-25 11:13:50 +02:00
..
ABI x86/vmscape: Enable the mitigation 2025-09-11 17:21:46 +02:00
accel accel/qaic: Add AIC080 support 2024-12-14 20:03:46 +01:00
accounting
admin-guide x86/bugs: KVM: Add support for SRSO_MSR_FIX 2025-09-25 11:13:49 +02:00
arch x86/bugs: Rename MDS machinery to something more generic 2025-07-10 16:05:14 +02:00
block
bpf bpf: Adjust free target to avoid global starvation of LRU map 2025-07-17 18:37:22 +02:00
cdrom
core-api module: Provide EXPORT_SYMBOL_GPL_FOR_MODULES() helper 2025-07-10 16:05:08 +02:00
cpu-freq
crypto
dev-tools The core clk framework is left largely untouched this time around except for 2024-09-23 15:01:48 -07:00
devicetree dt-bindings: serial: brcm,bcm7271-uart: Constrain clocks 2025-09-19 16:35:48 +02:00
doc-guide
driver-api serial: mctrl_gpio: split disable_ms into sync and no_sync APIs 2025-05-29 11:02:45 +02:00
fault-injection
fb
features
filesystems nfs/localio: add direct IO enablement with sync and async IO support 2025-09-19 16:35:43 +02:00
firmware_class
firmware-guide Documentation: ACPI: Fix parent device references 2025-08-20 18:30:15 +02:00
fpga
gpu drm/xe: Make xe_gt_freq part of the Documentation 2025-06-19 15:32:14 +02:00
hid
hwmon hwmon: (dell-smm) Increment the number of fans 2025-05-29 11:02:22 +02:00
i2c i2c: i801: Add support for Intel Panther Lake 2024-12-14 20:03:55 +01:00
iio docs: iio: ad7380: fix supply for ad7380-4 2024-10-24 18:30:47 +01:00
images
infiniband
input
isdn
kbuild kbuild: rust: add rustc-min-version support function 2025-06-27 11:11:40 +01:00
kernel-hacking
leds - Limited LED current based on thermal conditions in the QCOM flash LED driver. 2024-09-23 14:20:11 -07:00
litmus-tests
livepatch
locking kcsan, seqlock: Support seqcount_latch_t 2024-12-05 14:01:22 +01:00
maintainer
mhi
misc-devices
mm Docs/damon/maintainer-profile: update deprecated awslabs GitHub URLs 2024-10-17 00:28:09 -07:00
netlabel
netlink mptcp: pm: nl: announce deny-join-id0 flag 2025-09-25 11:13:50 +02:00
networking docs: networking: can: change bcm_msg_head frames member to support flexible array 2025-09-19 16:35:49 +02:00
nvdimm
nvme
PCI
pcmcia
peci
power Documentation: PM: Clarify pm_runtime_resume_and_get() return value 2024-12-19 18:13:15 +01:00
process soc: fixes for 6.12 2024-10-17 09:43:36 -07:00
RCU doc: rcu: update printed dynticks counter bits 2024-12-05 14:01:19 +01:00
rust rust: remove leftover mentions of the alloc crate 2025-03-22 12:54:23 -07:00
scheduler sched_ext: Documentation: Update instructions for running example schedulers 2024-10-08 08:49:18 -10:00
scsi
security landlock: Fix grammar issues in documentation 2024-10-21 20:36:26 +02:00
sound
sphinx
sphinx-static
spi
staging
target
tee
timers
tools
trace
translations module: Convert default symbol namespace to string literal 2025-02-08 09:57:05 +01:00
usb
userspace-api Landlock fix for v6.12-rc7 2024-11-12 13:01:09 -08:00
virt KVM: x86: Clean up documentation for KVM_X86_QUIRK_SLOT_ZAP_ALL 2024-10-20 07:31:05 -04:00
w1
watchdog [tree-wide] finally take no_llseek out 2024-09-27 08:18:43 -07:00
wmi platform/x86: msi-wmi-platform: Workaround a ACPI firmware bug 2025-04-25 10:48:04 +02:00
.gitignore
atomic_bitops.txt
atomic_t.txt
Changes
CodingStyle
conf.py
docutils.conf
dontdiff Kbuild updates for v6.12 2024-09-24 13:02:06 -07:00
index.rst
Kconfig
Makefile
memory-barriers.txt
SubmittingPatches
subsystem-apis.rst