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Message-ID: <fe323c90-bda3-4837-8daa-372073014446@linux.dev>
Date: Thu, 7 Mar 2024 17:03:43 -0800
From: Martin KaFai Lau <martin.lau@...ux.dev>
To: "Alessandro Carminati (Red Hat)" <alessandro.carminati@...il.com>
Cc: Mykola Lysenko <mykolal@...com>, Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>,
John Fastabend <john.fastabend@...il.com>, KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>, Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>, bpf@...r.kernel.org,
linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org,
Andrii Nakryiko <andrii@...nel.org>, Shuah Khan <shuah@...nel.org>
Subject: Re: [PATCH] tools/testing/selftests/bpf/test_tc_tunnel.sh: Prevent
client connect before server bind
On 2/29/24 6:00 AM, Alessandro Carminati (Red Hat) wrote:
> In some systems, the netcat server can incur in delay to start listening.
> When this happens, the test can randomly fail in various points.
> This is an example error message:
> # ip gre none gso
> # encap 192.168.1.1 to 192.168.1.2, type gre, mac none len 2000
> # test basic connectivity
> # Ncat: Connection refused.
This explained what is the issue. Please also explain how the patch solves it.
>
> Signed-off-by: Alessandro Carminati (Red Hat) <alessandro.carminati@...il.com>
> ---
> tools/testing/selftests/bpf/test_tc_tunnel.sh | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/bpf/test_tc_tunnel.sh b/tools/testing/selftests/bpf/test_tc_tunnel.sh
> index 910044f08908..01c0f4b1a8c2 100755
> --- a/tools/testing/selftests/bpf/test_tc_tunnel.sh
> +++ b/tools/testing/selftests/bpf/test_tc_tunnel.sh
> @@ -72,7 +72,6 @@ cleanup() {
> server_listen() {
> ip netns exec "${ns2}" nc "${netcat_opt}" -l "${port}" > "${outfile}" &
> server_pid=$!
> - sleep 0.2
> }
>
> client_connect() {
> @@ -93,6 +92,22 @@ verify_data() {
> fi
> }
>
> +wait_for_port() {
> + local digits=8
> + local port2check=$(printf ":%04X" $1)
> + local prot=$([ "$2" == "-6" ] && echo 6 && digits=32)
> +
> + for i in $(seq 20); do
> + if ip netns exec "${ns2}" cat /proc/net/tcp${prot} | \
> + sed -r 's/^[ \t]+[0-9]+: ([0-9A-F]{'${digits}'}:[0-9A-F]{4}) .*$/\1/' | \
> + grep -q "${port2check}"; then
The idea is to check if there is socket listening on port 8888?
May be something simpler like "ss -OHtl src :$1" instead?
--
pw-bot: cr
The check-and-wait fix in this patch is fine to get your test environment going.
Eventually, it will be good to see the test_tc_tunnel.sh test moved to
test_progs. The test_tc_tunnel.sh is not run by bpf CI and issue like this got
unnoticed. Some other "*.sh" tests have already been moved to test_progs.
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