From 1d206e8e4371ced5ac83516234c0ddd882d7abd2 Mon Sep 17 00:00:00 2001 From: "Matthieu Baerts (NGI0)" Date: Wed, 12 Aug 2026 16:55:44 +0200 Subject: [PATCH] selftests: mptcp: pcap: drop most of the payload Limit the size of each captured packet to 108B (IPv4 only) or 128B (a mix of v4 and v6): this should drop most of the payload that is generally not needed when debugging an issue. 8 bytes are left in this payload, to be able to inspect the beginning, just in case. Please also note that generally, this payload is usually mostly filled with 0, except at the end. This reduces the .pcap sizes, and reduce IO usage, which helps debugging issues. Reviewed-by: Mat Martineau Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20260812-net-next-mptcp-misc-feat-7-3-v1-9-1905a818f6cb@kernel.org Signed-off-by: Jakub Kicinski --- tools/testing/selftests/net/mptcp/mptcp_connect.sh | 2 +- tools/testing/selftests/net/mptcp/mptcp_join.sh | 2 +- tools/testing/selftests/net/mptcp/simult_flows.sh | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/net/mptcp/mptcp_connect.sh b/tools/testing/selftests/net/mptcp/mptcp_connect.sh index 5befd8584a4d..7a2a851fa0ad 100755 --- a/tools/testing/selftests/net/mptcp/mptcp_connect.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_connect.sh @@ -373,7 +373,7 @@ do_transfer() fi local capfile="${capprefix}-${connector_ns:0:3}-${listener_ns:0:3}-${cl_proto}-${srv_proto}-${connect_addr}-${port}" - local capopt="-i any -s 65535 -B 32768 ${capuser}" + local capopt="-i any -s 128 -B 32768 ${capuser}" ip netns exec ${listener_ns} tcpdump ${capopt} \ -w "${capfile}-listener.pcap" >> "${capout}" 2>&1 & diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh index 9b9fb3de9da3..18ce7136a2b0 100755 --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh @@ -979,7 +979,7 @@ cond_start_capture() capfile=$(printf "mp_join-%02u-%s.pcap" "$MPTCP_LIB_TEST_COUNTER" "$ns") echo "Capturing traffic for test $MPTCP_LIB_TEST_COUNTER into $capfile" - ip netns exec "$ns" tcpdump -i any -s 65535 -B 32768 $capuser -w "$capfile" > "$capout" 2>&1 & + ip netns exec "$ns" tcpdump -i any -s 128 -B 32768 $capuser -w "$capfile" > "$capout" 2>&1 & cappid=$! sleep 1 diff --git a/tools/testing/selftests/net/mptcp/simult_flows.sh b/tools/testing/selftests/net/mptcp/simult_flows.sh index d723261bdc62..3ea3d1efe32e 100755 --- a/tools/testing/selftests/net/mptcp/simult_flows.sh +++ b/tools/testing/selftests/net/mptcp/simult_flows.sh @@ -149,7 +149,7 @@ do_transfer() fi local capfile="${capprefix}-${port}" - local capopt="-i any -s 65535 -B 32768 ${capuser}" + local capopt="-i any -s 108 -B 32768 ${capuser}" ip netns exec ${ns3} tcpdump ${capopt} -w "${capfile}-listener.pcap" >> "${capout}" 2>&1 & local cappid_listener=$!