netdev - [PATCH net v3 0/2] net: tcp: lookup the best matched listen socket

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250802092435.288714-1-dongml2@chinatelecom.cn>
Date: Sat,  2 Aug 2025 17:24:33 +0800
From: Menglong Dong <menglong8.dong@...il.com>
To: edumazet@...gle.com,
	kuniyu@...gle.com
Cc: ncardwell@...gle.com,
	davem@...emloft.net,
	dsahern@...nel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	horms@...nel.org,
	shuah@...nel.org,
	kraig@...gle.com,
	linux-kernel@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Subject: [PATCH net v3 0/2] net: tcp: lookup the best matched listen socket

For now, the tcp socket lookup will terminate if the socket is reuse port
in inet_lhash2_lookup(), which makes the socket is not the best match.

For example, we have socket1 and socket2 both listen on "0.0.0.0:1234",
but socket1 bind on "eth0". We create socket1 first, and then socket2.
Then, all connections will goto socket2, which is not expected, as socket1
has higher priority.

The 1st patch fix this problem, and the 2nd patch is a selftests for this
problem. Without the 1st patch, the selftests will fail with:

$ ./tcp_reuseport.py
TAP version 13
1..1
FAIL: wrong assignment
not ok 1 tcp_reuseport.test_reuseport_select
Totals: pass:0 fail:1 xfail:0 xpass:0 skip:0 error:0

With the 1st patch, it will success:
$ ./tcp_reuseport.py
TAP version 13
1..1
SUCCESS: assigned properly: (<socket.socket fd=6, family=2, type=1, proto=0, laddr=('127.0.0.1', 33787), raddr=('127.0.0.1', 43140)>, ('127.0.0.1', 43140))
SUCCESS: assigned properly: (<socket.socket fd=5, family=2, type=1, proto=0, laddr=('127.0.0.1', 33787), raddr=('127.0.0.1', 43146)>, ('127.0.0.1', 43146))
SUCCESS: assigned properly: (<socket.socket fd=6, family=2, type=1, proto=0, laddr=('127.0.0.1', 33787), raddr=('127.0.0.1', 43162)>, ('127.0.0.1', 43162))
ok 1 tcp_reuseport.test_reuseport_select
Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:0

Changes since V2:
* use the approach in V1
* add the Fixes tag in the 1st patch
* introduce the selftests

Menglong Dong (2):
  net: tcp: lookup the best matched listen socket
  selftests/net: test TCP reuseport socket selection

 net/ipv4/inet_hashtables.c                   | 13 +++----
 net/ipv6/inet6_hashtables.c                  | 13 +++----
 tools/testing/selftests/net/Makefile         |  1 +
 tools/testing/selftests/net/tcp_reuseport.py | 36 ++++++++++++++++++++
 4 files changed, 51 insertions(+), 12 deletions(-)
 create mode 100755 tools/testing/selftests/net/tcp_reuseport.py

-- 
2.50.1