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Matthieu Baerts (NGI0) 85df533a78 mptcp: pm: do not ignore 'subflow' if 'signal' flag is also set
Up to the 'Fixes' commit, having an endpoint with both the 'signal' and
'subflow' flags, resulted in the creation of a subflow and an address
announcement using the address linked to this endpoint. After this
commit, only the address announcement was done, ignoring the 'subflow'
flag.

That's because the same bitmap is used for the two flags. It is OK to
keep this single bitmap, the already selected local endpoint simply have
to be re-used, but not via select_local_address() not to look at the
just modified bitmap.

Note that it is unusual to set the two flags together: creating a new
subflow using a new local address will implicitly advertise it to the
other peer. So in theory, no need to advertise it explicitly as well.
Maybe there are use-cases -- the subflow might not reach the other peer
that way, we can ask the other peer to try initiating the new subflow
without delay -- or very likely the user is confused, and put both flags
"just to be sure at least the right one is set". Still, if it is
allowed, the kernel should do what has been asked: using this endpoint
to announce the address and to create a new subflow from it.

An alternative is to forbid the use of the two flags together, but
that's probably too late, there are maybe use-cases, and it was working
before. This patch will avoid people complaining subflows are not
created using the endpoint they added with the 'subflow' and 'signal'
flag.

Note that with the current patch, the subflow might not be created in
some corner cases, e.g. if the 'subflows' limit was reached when sending
the ADD_ADDR, but changed later on. It is probably not worth splitting
id_avail_bitmap per target ('signal', 'subflow'), which will add another
large field to the msk "just" to track (again) endpoints. Anyway,
currently when the limits are changed, the kernel doesn't check if new
subflows can be created or removed, because we would need to keep track
of the received ADD_ADDR, and more. It sounds OK to assume that the
limits should be properly configured before establishing new
connections.

Fixes: 86e39e0448 ("mptcp: keep track of local endpoint still available for each msk")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20240731-upstream-net-20240731-mptcp-endp-subflow-signal-v1-5-c8a9b036493b@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-08-01 18:24:49 -07:00
Documentation Including fixes from wireless, bleutooth, BPF and netfilter. 2024-08-01 09:42:09 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
arch ARM updates for v6.11-rc1 2024-07-29 10:33:51 -07:00
block block: fix deadlock between sd_remove & sd_release 2024-07-24 09:51:21 -06:00
certs kbuild: use $(src) instead of $(srctree)/$(src) for source directory 2024-05-10 04:34:52 +09:00
crypto crypto: testmgr - generate power-of-2 lengths more often 2024-07-13 11:50:28 +12:00
drivers Including fixes from wireless, bleutooth, BPF and netfilter. 2024-08-01 09:42:09 -07:00
fs for-6.11-rc1-tag 2024-07-30 19:28:36 -07:00
include Including fixes from wireless, bleutooth, BPF and netfilter. 2024-08-01 09:42:09 -07:00
init Rust changes for v6.11 2024-07-27 13:44:54 -07:00
io_uring io_uring/napi: pass ktime to io_napi_adjust_timeout 2024-07-26 08:31:59 -06:00
ipc sysctl: treewide: constify the ctl_table argument of proc_handlers 2024-07-24 20:59:29 +02:00
kernel profiling: remove stale percpu flip buffer variables 2024-07-29 16:34:17 -07:00
lib minmax: don't use max() in situations that want a C constant expression 2024-07-28 20:23:27 -07:00
mm minmax: make generic MIN() and MAX() macros available everywhere 2024-07-28 15:49:18 -07:00
net mptcp: pm: do not ignore 'subflow' if 'signal' flag is also set 2024-08-01 18:24:49 -07:00
rust Rust changes for v6.11 2024-07-27 13:44:54 -07:00
samples Driver core changes for 6.11-rc1 2024-07-25 10:42:22 -07:00
scripts Kbuild fixes for v6.11 2024-07-28 14:02:48 -07:00
security apparmor-pr-2024-07-24 PR 2024-07-25 2024-07-27 13:28:39 -07:00
sound Devicetree fixes for 6.11, part 1 2024-07-27 12:46:16 -07:00
tools Including fixes from wireless, bleutooth, BPF and netfilter. 2024-08-01 09:42:09 -07:00
usr initramfs: shorten cmd_initfs in usr/Makefile 2024-07-16 01:07:52 +09:00
virt KVM generic changes for 6.11 2024-07-16 09:51:36 -04:00
.clang-format Docs: Move clang-format from process/ to dev-tools/ 2024-06-26 16:36:00 -06:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore kbuild: add script and target to generate pacman package 2024-07-22 01:24:22 +09:00
.mailmap MAINTAINERS: mailmap: update James Clark's email address 2024-07-26 14:32:35 -07:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS tracing: Update of MAINTAINERS and CREDITS file 2024-07-18 14:08:42 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Including fixes from wireless, bleutooth, BPF and netfilter. 2024-08-01 09:42:09 -07:00
Makefile Linux 6.11-rc1 2024-07-28 14:19:55 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.