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Ilpo Järvinen 4618e195f9 tcp: add new TCP_TW_ACK_OOW state and allow ECN bits in TOS
ECN bits in TOS are always cleared when sending in ACKs in TW. Clearing
them is problematic for TCP flows that used Accurate ECN because ECN bits
decide which service queue the packet is placed into (L4S vs Classic).
Effectively, TW ACKs are always downgraded from L4S to Classic queue
which might impact, e.g., delay the ACK will experience on the path
compared with the other packets of the flow.

Change the TW ACK sending code to differentiate:
- In tcp_v4_send_reset(), commit ba9e04a7dd ("ip: fix tos reflection
  in ack and reset packets") cleans ECN bits for TW reset and this is
  not affected.
- In tcp_v4_timewait_ack(), ECN bits for all TW ACKs are cleaned. But now
  only ECN bits of ACKs for oow data or paws_reject are cleaned, and ECN
  bits of other ACKs will not be cleaned.
- In tcp_v4_reqsk_send_ack(), commit 66b13d99d9 ("ipv4: tcp: fix TOS
  value in ACK messages sent from TIME_WAIT") did not clean ECN bits of
  ACKs for oow data or paws_reject. But now the ECN bits rae cleaned for
  these ACKs.

Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2025-03-17 13:56:17 +00:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
block block-6.14-20250306 2025-03-07 11:12:33 -10:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
Documentation Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
drivers Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
include tcp: add new TCP_TW_ACK_OOW state and allow ECN bits in TOS 2025-03-17 13:56:17 +00:00
init Kbuild updates for v6.14 2025-01-31 12:07:07 -08:00
io_uring Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
lib Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm 33 hotfixes. 24 are cc:stable and the remainder address post-6.13 issues 2025-03-08 14:34:06 -10:00
net tcp: add new TCP_TW_ACK_OOW state and allow ECN bits in TOS 2025-03-17 13:56:17 +00:00
rust Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
samples Driver core api addition for 6.14-rc3 2025-02-16 12:54:42 -08:00
scripts Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
security Landlock fix for v6.14-rc5 2025-02-26 11:55:44 -08:00
sound ALSA: hda/realtek: Add support for ASUS Zenbook UM3406KA Laptops using CS35L41 HDA 2025-03-05 19:52:56 +01:00
tools selftests: drv-net: fix merge conflicts resolution 2025-03-14 10:24:14 +01:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt KVM: remove kvm_arch_post_init_vm 2025-02-04 11:27:45 -05:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap 33 hotfixes. 24 are cc:stable and the remainder address post-6.13 issues 2025-03-08 14:34:06 -10:00
.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 MAINTAINERS: Move Pavel to kernel.org address 2025-02-07 09:12:33 -08:00
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 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-03-13 23:08:11 +01:00
Makefile Linux 6.14-rc6 2025-03-09 13:45:25 -10:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.