[PATCH net] selftests: openvswitch: fix tcpdump execution

[PATCH net] selftests: openvswitch: fix tcpdump execution

[Adrian Moreno]

Fix the way tcpdump is executed by:
- Using the right variable for the namespace. Currently the use of the
  empty "ns" makes the command fail.
- Waiting until it starts to capture to ensure the interesting traffic
  is caught on slow systems.
- Using line-buffered output to ensure logs are available when the test
  is paused with "-p". Otherwise the last chunk of data might only be
  written when tcpdump is killed.

Fixes: 74cc26f416b9 ("selftests: openvswitch: add interface support")
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
---
 tools/testing/selftests/net/openvswitch/openvswitch.sh | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/net/openvswitch/openvswitch.sh b/tools/testing/selftests/net/openvswitch/openvswitch.sh
index cc0bfae2bafa..960e1ab4dd04 100755
--- a/tools/testing/selftests/net/openvswitch/openvswitch.sh
+++ b/tools/testing/selftests/net/openvswitch/openvswitch.sh
@@ -171,8 +171,10 @@ ovs_add_netns_and_veths () {
 		ovs_add_if "$1" "$2" "$4" -u || return 1
 	fi
 
-	[ $TRACING -eq 1 ] && ovs_netns_spawn_daemon "$1" "$ns" \
-			tcpdump -i any -s 65535
+	if [ $TRACING -eq 1 ]; then
+		ovs_netns_spawn_daemon "$1" "$3" tcpdump -l -i any -s 6553
+		ovs_wait grep -q "listening on any" ${ovs_dir}/stderr
+	fi
 
 	return 0
 }
-- 
2.47.1

Re: [ovs-dev] [PATCH net] selftests: openvswitch: fix tcpdump execution

[Eelco Chaudron]

On 17 Dec 2024, at 22:16, Adrian Moreno wrote:

> Fix the way tcpdump is executed by:
> - Using the right variable for the namespace. Currently the use of the
>   empty "ns" makes the command fail.
> - Waiting until it starts to capture to ensure the interesting traffic
>   is caught on slow systems.
> - Using line-buffered output to ensure logs are available when the test
>   is paused with "-p". Otherwise the last chunk of data might only be
>   written when tcpdump is killed.
>
> Fixes: 74cc26f416b9 ("selftests: openvswitch: add interface support")
> Signed-off-by: Adrian Moreno <amorenoz@redhat.com>

Thank for fixing this, the change looks good to me.

Acked-by: Eelco Chaudron <echaudro@redhat.com>

Re: [PATCH net] selftests: openvswitch: fix tcpdump execution

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 17 Dec 2024 22:16:51 +0100 you wrote:
> Fix the way tcpdump is executed by:
> - Using the right variable for the namespace. Currently the use of the
>   empty "ns" makes the command fail.
> - Waiting until it starts to capture to ensure the interesting traffic
>   is caught on slow systems.
> - Using line-buffered output to ensure logs are available when the test
>   is paused with "-p". Otherwise the last chunk of data might only be
>   written when tcpdump is killed.
> 
> [...]

Here is the summary with links:
  - [net] selftests: openvswitch: fix tcpdump execution
    https://git.kernel.org/netdev/net/c/a17975992cc1

You are awesome, thank you!
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