From: Paolo Abeni pabeni@redhat.com
commit e35f885b357d47e04380a2056d1b2cc3e6f4f24b upstream.
Since commit 2843ff6f36db ("mptcp: remote addresses fullmesh"), an MPTCP client can attempt creating multiple MPJ subflow simultaneusly.
In such scenario the server, when syncookies are enabled, could end-up accepting incoming MPJ syn even above the configured subflow limit, as the such limit can be enforced in a reliable way only after the subflow creation. In case of syncookie, only after the 3rd ack reception.
As a consequence the related self-tests case sporadically fails, as it verify that the server always accept the expected number of MPJ syn.
Address the issues relaxing the MPJ syn number constrain. Note that the check on the accepted number of MPJ 3rd ack still remains intact.
Fixes: 2843ff6f36db ("mptcp: remote addresses fullmesh") Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Mat Martineau mathew.j.martineau@linux.intel.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/net/mptcp/mptcp_join.sh | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh @@ -624,6 +624,7 @@ chk_join_nr() local ack_nr=$4 local count local dump_stats + local with_cookie
printf "%02u %-36s %s" "$TEST_COUNT" "$msg" "syn" count=`ip netns exec $ns1 nstat -as | grep MPTcpExtMPJoinSynRx | awk '{print $2}'` @@ -637,12 +638,20 @@ chk_join_nr() fi
echo -n " - synack" + with_cookie=`ip netns exec $ns2 sysctl -n net.ipv4.tcp_syncookies` count=`ip netns exec $ns2 nstat -as | grep MPTcpExtMPJoinSynAckRx | awk '{print $2}'` [ -z "$count" ] && count=0 if [ "$count" != "$syn_ack_nr" ]; then - echo "[fail] got $count JOIN[s] synack expected $syn_ack_nr" - ret=1 - dump_stats=1 + # simult connections exceeding the limit with cookie enabled could go up to + # synack validation as the conn limit can be enforced reliably only after + # the subflow creation + if [ "$with_cookie" = 2 ] && [ "$count" -gt "$syn_ack_nr" ] && [ "$count" -le "$syn_nr" ]; then + echo -n "[ ok ]" + else + echo "[fail] got $count JOIN[s] synack expected $syn_ack_nr" + ret=1 + dump_stats=1 + fi else echo -n "[ ok ]" fi