linux/include
Matthieu Baerts (NGI0) 2293c57484 mptcp: pm: nl: announce deny-join-id0 flag
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>
History 2025-09-15 18:12:05 -07:00
..
acpi mailbox/pcc: support mailbox management of the shared buffer 2025-08-07 23:49:56 -05:00
asm-generic Deferred unwind changes for 6.17 2025-08-01 09:46:24 -07:00
clocksource KVM/arm64 updates for 6.14 2025-01-28 09:01:36 -08:00
crypto This push fixes a regression that breaks hmac(sha3-224-s390). 2025-08-09 07:26:19 +03:00
cxl cxl/events: Trace Memory Sparing Event Record 2025-07-18 08:19:56 -07:00
drm drm/gpuvm: fix various typos in .c and .h gpuvm file 2025-08-25 21:48:50 +02:00
dt-bindings Pin control changes for v6.17 2025-08-02 12:07:09 -07:00
hyperv hyperv-next for v6.16 2025-06-03 08:39:20 -07:00
keys rxrpc: Add YFS RxGK (GSSAPI) security class 2025-04-14 17:36:41 -07:00
kunit linux_kselftest-kunit-6.17-rc1 2025-07-29 12:43:10 -07:00
kvm KVM/arm64 changes for 6.17, round #1 2025-07-29 12:27:40 -04:00
linux Including fixes from CAN, netfilter and wireless. 2025-09-11 08:54:42 -07:00
math-emu powerpc/math-emu: Remove -w build flag and fix warnings 2022-09-05 17:28:25 +10:00
media media: core: export v4l2_translate_cmd 2025-07-11 19:27:28 +02:00
memory memory: renesas-rpc-if: Add RZ/G3E xSPI support 2025-05-01 12:22:25 +02:00
misc cxl: Remove driver 2025-03-16 22:04:27 +11:00
net net: dst_metadata: fix IP_DF bit not extracted from tunnel headers 2025-09-14 14:28:12 -07:00
pcmcia pcmcia: remove PCCARD_IODYN 2025-08-16 15:37:47 +02:00
ras tracing, AER: Hide PCIe AER event when PCIEAER is not configured 2025-07-21 16:40:56 -04:00
rdma IB: Extend UVERBS_METHOD_REG_MR to get DMAH 2025-07-23 01:42:11 -04:00
rv rv: Retry when da monitor detects race conditions 2025-07-28 16:47:34 -04:00
scsi Merge patch series "libsas cleanups" 2025-07-25 09:05:23 -04:00
soc This is the usual collection of primarily clk driver updates. The big part of 2025-07-31 13:36:27 -07:00
sound ASoC: Fixes for v6.17 2025-08-21 09:02:28 +02:00
target scsi: target: core: Constify enabled() in struct target_opcode_descriptor 2025-05-20 22:11:03 -04:00
trace tracing changes for 6.17 2025-08-01 10:29:36 -07:00
uapi mptcp: pm: nl: announce deny-join-id0 flag 2025-09-15 18:12:05 -07:00
ufs Merge patch series "ufs: ufs-qcom: Align programming sequence as per HW spec" 2025-07-14 21:00:41 -04:00
vdso vdso/gettimeofday: Add support for auxiliary clocks 2025-07-18 14:09:39 +02:00
video video: Make global edid_info depend on CONFIG_FIRMWARE_EDID 2025-06-16 11:00:29 +02:00
xen Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00