[PATCH net 0/7] mptcp: Fix address advertisement races and stabilize tests

[PATCH net 0/7] mptcp: Fix address advertisement races and stabilize tests

[Mat Martineau]

Patches 1, 2, and 7 modify two self tests to give consistent, accurate
results by fixing timing issues and accounting for syncookie behavior.

Paches 3-6 fix two races in overlapping address advertisement send and
receive. Associated self tests are updated, including addition of two
MIBs to enable testing and tracking dropped address events.


Paolo Abeni (7):
  selftests: mptcp: fix diag instability
  selftests: mptcp: improve 'fair usage on close' stability
  mptcp: fix race in overlapping signal events
  mptcp: fix race in incoming ADD_ADDR option processing
  mptcp: add mibs counter for ignored incoming options
  selftests: mptcp: more robust signal race test
  selftests: mptcp: be more conservative with cookie MPJ limits

 net/mptcp/mib.c                               |  2 +
 net/mptcp/mib.h                               |  2 +
 net/mptcp/pm.c                                |  8 +++-
 net/mptcp/pm_netlink.c                        | 29 +++++++++---
 tools/testing/selftests/net/mptcp/diag.sh     | 44 ++++++++++++++++---
 .../testing/selftests/net/mptcp/mptcp_join.sh | 32 +++++++++++---
 6 files changed, 96 insertions(+), 21 deletions(-)


base-commit: b352c3465bb808ab700d03f5bac2f7a6f37c5350
-- 
2.35.1

[PATCH net 1/7] selftests: mptcp: fix diag instability

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

Instead of waiting for an arbitrary amount of time for the MPTCP
MP_CAPABLE handshake to complete, explicitly wait for the relevant
socket to enter into the established status.

Additionally let the data transfer application use the slowest
transfer mode available (-r), to cope with very slow host, or
high jitter caused by hosting VMs.

Fixes: df62f2ec3df6 ("selftests/mptcp: add diag interface tests")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/258
Reported-and-tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 tools/testing/selftests/net/mptcp/diag.sh | 44 +++++++++++++++++++----
 1 file changed, 37 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/diag.sh b/tools/testing/selftests/net/mptcp/diag.sh
index 2674ba20d524..ff821025d309 100755
--- a/tools/testing/selftests/net/mptcp/diag.sh
+++ b/tools/testing/selftests/net/mptcp/diag.sh
@@ -71,6 +71,36 @@ chk_msk_remote_key_nr()
 		__chk_nr "grep -c remote_key" $*
 }
 
+# $1: ns, $2: port
+wait_local_port_listen()
+{
+	local listener_ns="${1}"
+	local port="${2}"
+
+	local port_hex i
+
+	port_hex="$(printf "%04X" "${port}")"
+	for i in $(seq 10); do
+		ip netns exec "${listener_ns}" cat /proc/net/tcp | \
+			awk "BEGIN {rc=1} {if (\$2 ~ /:${port_hex}\$/ && \$4 ~ /0A/) {rc=0; exit}} END {exit rc}" &&
+			break
+		sleep 0.1
+	done
+}
+
+wait_connected()
+{
+	local listener_ns="${1}"
+	local port="${2}"
+
+	local port_hex i
+
+	port_hex="$(printf "%04X" "${port}")"
+	for i in $(seq 10); do
+		ip netns exec ${listener_ns} grep -q " 0100007F:${port_hex} " /proc/net/tcp && break
+		sleep 0.1
+	done
+}
 
 trap cleanup EXIT
 ip netns add $ns
@@ -81,15 +111,15 @@ echo "a" | \
 		ip netns exec $ns \
 			./mptcp_connect -p 10000 -l -t ${timeout_poll} \
 				0.0.0.0 >/dev/null &
-sleep 0.1
+wait_local_port_listen $ns 10000
 chk_msk_nr 0 "no msk on netns creation"
 
 echo "b" | \
 	timeout ${timeout_test} \
 		ip netns exec $ns \
-			./mptcp_connect -p 10000 -j -t ${timeout_poll} \
+			./mptcp_connect -p 10000 -r 0 -t ${timeout_poll} \
 				127.0.0.1 >/dev/null &
-sleep 0.1
+wait_connected $ns 10000
 chk_msk_nr 2 "after MPC handshake "
 chk_msk_remote_key_nr 2 "....chk remote_key"
 chk_msk_fallback_nr 0 "....chk no fallback"
@@ -101,13 +131,13 @@ echo "a" | \
 		ip netns exec $ns \
 			./mptcp_connect -p 10001 -l -s TCP -t ${timeout_poll} \
 				0.0.0.0 >/dev/null &
-sleep 0.1
+wait_local_port_listen $ns 10001
 echo "b" | \
 	timeout ${timeout_test} \
 		ip netns exec $ns \
-			./mptcp_connect -p 10001 -j -t ${timeout_poll} \
+			./mptcp_connect -p 10001 -r 0 -t ${timeout_poll} \
 				127.0.0.1 >/dev/null &
-sleep 0.1
+wait_connected $ns 10001
 chk_msk_fallback_nr 1 "check fallback"
 flush_pids
 
@@ -119,7 +149,7 @@ for I in `seq 1 $NR_CLIENTS`; do
 				./mptcp_connect -p $((I+10001)) -l -w 10 \
 					-t ${timeout_poll} 0.0.0.0 >/dev/null &
 done
-sleep 0.1
+wait_local_port_listen $ns $((NR_CLIENTS + 10001))
 
 for I in `seq 1 $NR_CLIENTS`; do
 	echo "b" | \
-- 
2.35.1

[PATCH net 2/7] selftests: mptcp: improve 'fair usage on close' stability

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

The mentioned test has to wait for a subflow creation failure.
The current code looks for TCP sockets in TW state and sometimes
misses the relevant event. Switch to a more stable check, looking
for the associated mib counter.

Fixes: 46e967d187ed ("selftests: mptcp: add tests for subflow creation failure")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/257
Reported-and-tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index c0801df15f54..10b3bd805ac6 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -961,7 +961,7 @@ wait_for_tw()
 	local ns=$1
 
 	while [ $time -lt $timeout_ms ]; do
-		local cnt=$(ip netns exec $ns ss -t state time-wait |wc -l)
+		local cnt=$(ip netns exec $ns nstat -as TcpAttemptFails | grep TcpAttemptFails | awk '{print $2}')
 
 		[ "$cnt" = 1 ] && return 1
 		time=$((time + 100))
-- 
2.35.1

[PATCH net 3/7] mptcp: fix race in overlapping signal events

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

After commit a88c9e496937 ("mptcp: do not block subflows
creation on errors"), if a signal address races with a failing
subflow creation, the subflow creation failure control path
can trigger the selection of the next address to be announced
while the current announced is still pending.

The above will cause the unintended suppression of the ADD_ADDR
announce.

Fix the issue skipping the to-be-suppressed announce before it
will mark an endpoint as already used. The relevant announce
will be triggered again when the current one will complete.

Fixes: a88c9e496937 ("mptcp: do not block subflows creation on errors")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 356f596e2032..82f82a513f5b 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -546,6 +546,16 @@ static void mptcp_pm_create_subflow_or_signal_addr(struct mptcp_sock *msk)
 	if (msk->pm.add_addr_signaled < add_addr_signal_max) {
 		local = select_signal_address(pernet, msk);
 
+		/* due to racing events on both ends we can reach here while
+		 * previous add address is still running: if we invoke now
+		 * mptcp_pm_announce_addr(), that will fail and the
+		 * corresponding id will be marked as used.
+		 * Instead let the PM machinery reschedule us when the
+		 * current address announce will be completed.
+		 */
+		if (msk->pm.addr_signal & BIT(MPTCP_ADD_ADDR_SIGNAL))
+			return;
+
 		if (local) {
 			if (mptcp_pm_alloc_anno_list(msk, local)) {
 				__clear_bit(local->addr.id, msk->pm.id_avail_bitmap);
-- 
2.35.1

[PATCH net 4/7] mptcp: fix race in incoming ADD_ADDR option processing

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

If an MPTCP endpoint received multiple consecutive incoming
ADD_ADDR options, mptcp_pm_add_addr_received() can overwrite
the current remote address value after the PM lock is released
in mptcp_pm_nl_add_addr_received() and before such address
is echoed.

Fix the issue caching the remote address value a little earlier
and always using the cached value after releasing the PM lock.

Fixes: f7efc7771eac ("mptcp: drop argument port from mptcp_pm_announce_addr")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/pm_netlink.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 82f82a513f5b..4b5d795383cd 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -660,6 +660,7 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 	unsigned int add_addr_accept_max;
 	struct mptcp_addr_info remote;
 	unsigned int subflows_max;
+	bool reset_port = false;
 	int i, nr;
 
 	add_addr_accept_max = mptcp_pm_get_add_addr_accept_max(msk);
@@ -669,15 +670,19 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		 msk->pm.add_addr_accepted, add_addr_accept_max,
 		 msk->pm.remote.family);
 
-	if (lookup_subflow_by_daddr(&msk->conn_list, &msk->pm.remote))
+	remote = msk->pm.remote;
+	if (lookup_subflow_by_daddr(&msk->conn_list, &remote))
 		goto add_addr_echo;
 
+	/* pick id 0 port, if none is provided the remote address */
+	if (!remote.port) {
+		reset_port = true;
+		remote.port = sk->sk_dport;
+	}
+
 	/* connect to the specified remote address, using whatever
 	 * local address the routing configuration will pick.
 	 */
-	remote = msk->pm.remote;
-	if (!remote.port)
-		remote.port = sk->sk_dport;
 	nr = fill_local_addresses_vec(msk, addrs);
 
 	msk->pm.add_addr_accepted++;
@@ -690,8 +695,12 @@ static void mptcp_pm_nl_add_addr_received(struct mptcp_sock *msk)
 		__mptcp_subflow_connect(sk, &addrs[i], &remote);
 	spin_lock_bh(&msk->pm.lock);
 
+	/* be sure to echo exactly the received address */
+	if (reset_port)
+		remote.port = 0;
+
 add_addr_echo:
-	mptcp_pm_announce_addr(msk, &msk->pm.remote, true);
+	mptcp_pm_announce_addr(msk, &remote, true);
 	mptcp_pm_nl_addr_send_ack(msk);
 }
 
-- 
2.35.1

[PATCH net 5/7] mptcp: add mibs counter for ignored incoming options

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

The MPTCP in kernel path manager has some constraints on incoming
addresses announce processing, so that in edge scenarios it can
end-up dropping (ignoring) some of such announces.

The above is not very limiting in practice since such scenarios are
very uncommon and MPTCP will recover due to ADD_ADDR retransmissions.

This patch adds a few MIB counters to account for such drop events
to allow easier introspection of the critical scenarios.

Fixes: f7efc7771eac ("mptcp: drop argument port from mptcp_pm_announce_addr")
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 net/mptcp/mib.c | 2 ++
 net/mptcp/mib.h | 2 ++
 net/mptcp/pm.c  | 8 ++++++--
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index 3240b72271a7..7558802a1435 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -35,12 +35,14 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("AddAddr", MPTCP_MIB_ADDADDR),
 	SNMP_MIB_ITEM("EchoAdd", MPTCP_MIB_ECHOADD),
 	SNMP_MIB_ITEM("PortAdd", MPTCP_MIB_PORTADD),
+	SNMP_MIB_ITEM("AddAddrDrop", MPTCP_MIB_ADDADDRDROP),
 	SNMP_MIB_ITEM("MPJoinPortSynRx", MPTCP_MIB_JOINPORTSYNRX),
 	SNMP_MIB_ITEM("MPJoinPortSynAckRx", MPTCP_MIB_JOINPORTSYNACKRX),
 	SNMP_MIB_ITEM("MPJoinPortAckRx", MPTCP_MIB_JOINPORTACKRX),
 	SNMP_MIB_ITEM("MismatchPortSynRx", MPTCP_MIB_MISMATCHPORTSYNRX),
 	SNMP_MIB_ITEM("MismatchPortAckRx", MPTCP_MIB_MISMATCHPORTACKRX),
 	SNMP_MIB_ITEM("RmAddr", MPTCP_MIB_RMADDR),
+	SNMP_MIB_ITEM("RmAddrDrop", MPTCP_MIB_RMADDRDROP),
 	SNMP_MIB_ITEM("RmSubflow", MPTCP_MIB_RMSUBFLOW),
 	SNMP_MIB_ITEM("MPPrioTx", MPTCP_MIB_MPPRIOTX),
 	SNMP_MIB_ITEM("MPPrioRx", MPTCP_MIB_MPPRIORX),
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index ecd3d8b117e0..2966fcb6548b 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -28,12 +28,14 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_ADDADDR,		/* Received ADD_ADDR with echo-flag=0 */
 	MPTCP_MIB_ECHOADD,		/* Received ADD_ADDR with echo-flag=1 */
 	MPTCP_MIB_PORTADD,		/* Received ADD_ADDR with a port-number */
+	MPTCP_MIB_ADDADDRDROP,		/* Dropped incoming ADD_ADDR */
 	MPTCP_MIB_JOINPORTSYNRX,	/* Received a SYN MP_JOIN with a different port-number */
 	MPTCP_MIB_JOINPORTSYNACKRX,	/* Received a SYNACK MP_JOIN with a different port-number */
 	MPTCP_MIB_JOINPORTACKRX,	/* Received an ACK MP_JOIN with a different port-number */
 	MPTCP_MIB_MISMATCHPORTSYNRX,	/* Received a SYN MP_JOIN with a mismatched port-number */
 	MPTCP_MIB_MISMATCHPORTACKRX,	/* Received an ACK MP_JOIN with a mismatched port-number */
 	MPTCP_MIB_RMADDR,		/* Received RM_ADDR */
+	MPTCP_MIB_RMADDRDROP,		/* Dropped incoming RM_ADDR */
 	MPTCP_MIB_RMSUBFLOW,		/* Remove a subflow */
 	MPTCP_MIB_MPPRIOTX,		/* Transmit a MP_PRIO */
 	MPTCP_MIB_MPPRIORX,		/* Received a MP_PRIO */
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index 696b2c4613a7..7bea318ac5f2 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -213,6 +213,8 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
 		mptcp_pm_add_addr_send_ack(msk);
 	} else if (mptcp_pm_schedule_work(msk, MPTCP_PM_ADD_ADDR_RECEIVED)) {
 		pm->remote = *addr;
+	} else {
+		__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_ADDADDRDROP);
 	}
 
 	spin_unlock_bh(&pm->lock);
@@ -253,8 +255,10 @@ void mptcp_pm_rm_addr_received(struct mptcp_sock *msk,
 		mptcp_event_addr_removed(msk, rm_list->ids[i]);
 
 	spin_lock_bh(&pm->lock);
-	mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED);
-	pm->rm_list_rx = *rm_list;
+	if (mptcp_pm_schedule_work(msk, MPTCP_PM_RM_ADDR_RECEIVED))
+		pm->rm_list_rx = *rm_list;
+	else
+		__MPTCP_INC_STATS(sock_net((struct sock *)msk), MPTCP_MIB_RMADDRDROP);
 	spin_unlock_bh(&pm->lock);
 }
 
-- 
2.35.1

[PATCH net 6/7] selftests: mptcp: more robust signal race test

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

The in kernel MPTCP PM implementation can process a single
incoming add address option at any given time. In the
mentioned test the server can surpass such limit. Let the
setup cope with that allowing a faster add_addr retransmission.

Fixes: a88c9e496937 ("mptcp: do not block subflows creation on errors")
Fixes: f7efc7771eac ("mptcp: drop argument port from mptcp_pm_announce_addr")
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/254
Reported-and-tested-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Reviewed-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 10b3bd805ac6..0d6a71e7bb59 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -752,11 +752,17 @@ chk_add_nr()
 	local mis_ack_nr=${8:-0}
 	local count
 	local dump_stats
+	local timeout
+
+	timeout=`ip netns exec $ns1 sysctl -n net.mptcp.add_addr_timeout`
 
 	printf "%-39s %s" " " "add"
-	count=`ip netns exec $ns2 nstat -as | grep MPTcpExtAddAddr | awk '{print $2}'`
+	count=`ip netns exec $ns2 nstat -as MPTcpExtAddAddr | grep MPTcpExtAddAddr | awk '{print $2}'`
 	[ -z "$count" ] && count=0
-	if [ "$count" != "$add_nr" ]; then
+
+	# if the test configured a short timeout tolerate greater then expected
+	# add addrs options, due to retransmissions
+	if [ "$count" != "$add_nr" ] && [ "$timeout" -gt 1 -o "$count" -lt "$add_nr" ]; then
 		echo "[fail] got $count ADD_ADDR[s] expected $add_nr"
 		ret=1
 		dump_stats=1
@@ -1158,7 +1164,10 @@ signal_address_tests()
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags signal
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags signal
 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.4.2 flags signal
-	run_tests $ns1 $ns2 10.0.1.1
+
+	# the peer could possibly miss some addr notification, allow retransmission
+	ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=1
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
 	chk_join_nr "signal addresses race test" 3 3 3
 
 	# the server will not signal the address terminating
-- 
2.35.1

[PATCH net 7/7] selftests: mptcp: be more conservative with cookie MPJ limits

[Mat Martineau]

From: Paolo Abeni <pabeni@redhat.com>

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>
---
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 0d6a71e7bb59..0c8a2a20b96c 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -660,6 +660,7 @@ 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}'`
@@ -673,12 +674,20 @@ 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
-- 
2.35.1

Re: [PATCH net 6/7] selftests: mptcp: more robust signal race test

[Mat Martineau]

On Fri, 18 Feb 2022, Mat Martineau wrote:

> From: Paolo Abeni <pabeni@redhat.com>
>
> The in kernel MPTCP PM implementation can process a single
> incoming add address option at any given time. In the
> mentioned test the server can surpass such limit. Let the
> setup cope with that allowing a faster add_addr retransmission.
>

Jakub / David -

A heads-up, this patch will give a trivial merge conflict in the hunk 
below when merging net/master to net-next/master. It's only due to changes 
in the preceeding context (those "ip netns exec" lines), so conflict 
resolution will be obvious.


> diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
> index 10b3bd805ac6..0d6a71e7bb59 100755
> --- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
> +++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh

...

> @@ -1158,7 +1164,10 @@ signal_address_tests()
> 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags signal
> 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.3.2 flags signal
> 	ip netns exec $ns2 ./pm_nl_ctl add 10.0.4.2 flags signal
> -	run_tests $ns1 $ns2 10.0.1.1
> +
> +	# the peer could possibly miss some addr notification, allow retransmission
> +	ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=1
> +	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow
> 	chk_join_nr "signal addresses race test" 3 3 3
>
> 	# the server will not signal the address terminating
> -- 
> 2.35.1
>
>

--
Mat Martineau
Intel

Re: [PATCH net 0/7] mptcp: Fix address advertisement races and stabilize tests

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Fri, 18 Feb 2022 13:35:37 -0800 you wrote:
> Patches 1, 2, and 7 modify two self tests to give consistent, accurate
> results by fixing timing issues and accounting for syncookie behavior.
> 
> Paches 3-6 fix two races in overlapping address advertisement send and
> receive. Associated self tests are updated, including addition of two
> MIBs to enable testing and tracking dropped address events.
> 
> [...]

Here is the summary with links:
  - [net,1/7] selftests: mptcp: fix diag instability
    https://git.kernel.org/netdev/net/c/0cd33c5ffec1
  - [net,2/7] selftests: mptcp: improve 'fair usage on close' stability
    https://git.kernel.org/netdev/net/c/5b31dda736e3
  - [net,3/7] mptcp: fix race in overlapping signal events
    https://git.kernel.org/netdev/net/c/98247bc16a27
  - [net,4/7] mptcp: fix race in incoming ADD_ADDR option processing
    https://git.kernel.org/netdev/net/c/837cf45df163
  - [net,5/7] mptcp: add mibs counter for ignored incoming options
    https://git.kernel.org/netdev/net/c/f73c11946345
  - [net,6/7] selftests: mptcp: more robust signal race test
    https://git.kernel.org/netdev/net/c/6ef84b1517e0
  - [net,7/7] selftests: mptcp: be more conservative with cookie MPJ limits
    https://git.kernel.org/netdev/net/c/e35f885b357d

You are awesome, thank you!
-- 
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