selftests: mptcp: join: skip check if MIB counter not supported

Selftests are supposed to run on any kernels, including the old ones not
supporting all MPTCP features.

One of them is the MPTCP MIB counters introduced in commit fc518953bc9c
("mptcp: add and use MIB counter infrastructure") and more later. The
MPTCP Join selftest heavily relies on these counters.

If a counter is not supported by the kernel, it is not displayed when
using 'nstat -z'. We can then detect that and skip the verification. A
new helper (get_counter()) has been added to do the required checks and
return an error if the counter is not available.

Note that if we expect to have these features available and if
SELFTESTS_MPTCP_LIB_EXPECT_ALL_FEATURES env var is set to 1, the tests
will be marked as failed instead of skipped.

This new helper also makes sure we get the exact counter we want to
avoid issues we had in the past, e.g. with MPTcpExtRmAddr and
MPTcpExtRmAddrDrop sharing the same prefix. While at it, we uniform the
way we fetch a MIB counter.

Note for the backports: we rarely change these modified blocks so if
there is are conflicts, it is very likely because a counter is not used
in the older kernels and we don't need that chunk.

Link: https://github.com/multipath-tcp/mptcp_net-next/issues/368
Fixes: b08fbf241064 ("selftests: add test-cases for MPTCP MP_JOIN")
Cc: stable@vger.kernel.org
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index a63aed145393a1b9bca69b85d0175e0103c4e701..276396cbe60c1813037ae7be00351f52f70c0325 100755 (executable)
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -500,11 +500,25 @@ wait_local_port_listen()
        done
 }
 
-rm_addr_count()
+# $1: ns ; $2: counter
+get_counter()
 {
-       local ns=${1}
+       local ns="${1}"
+       local counter="${2}"
+       local count
+
+       count=$(ip netns exec ${ns} nstat -asz "${counter}" | awk 'NR==1 {next} {print $2}')
+       if [ -z "${count}" ]; then
+               mptcp_lib_fail_if_expected_feature "${counter} counter"
+               return 1
+       fi
 
-       ip netns exec ${ns} nstat -as | grep MPTcpExtRmAddr | awk '{print $2}'
+       echo "${count}"
+}
+
+rm_addr_count()
+{
+       get_counter "${1}" "MPTcpExtRmAddr"
 }
 
 # $1: ns, $2: old rm_addr counter in $ns
@@ -527,11 +541,11 @@ wait_mpj()
        local ns="${1}"
        local cnt old_cnt
 
-       old_cnt=$(ip netns exec ${ns} nstat -as | grep MPJoinAckRx | awk '{print $2}')
+       old_cnt=$(get_counter ${ns} "MPTcpExtMPJoinAckRx")
 
        local i
        for i in $(seq 10); do
-               cnt=$(ip netns exec ${ns} nstat -as | grep MPJoinAckRx | awk '{print $2}')
+               cnt=$(get_counter ${ns} "MPTcpExtMPJoinAckRx")
                [ "$cnt" = "${old_cnt}" ] || break
                sleep 0.1
        done
@@ -1190,12 +1204,13 @@ chk_csum_nr()
        fi
 
        printf "%-${nr_blank}s %s" " " "sum"
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtDataCsumErr | awk '{print $2}')
-       [ -z "$count" ] && count=0
+       count=$(get_counter ${ns1} "MPTcpExtDataCsumErr")
        if [ "$count" != "$csum_ns1" ]; then
                extra_msg="$extra_msg ns1=$count"
        fi
-       if { [ "$count" != $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 0 ]; } ||
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif { [ "$count" != $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 0 ]; } ||
           { [ "$count" -lt $csum_ns1 ] && [ $allow_multi_errors_ns1 -eq 1 ]; }; then
                echo "[fail] got $count data checksum error[s] expected $csum_ns1"
                fail_test
@@ -1204,12 +1219,13 @@ chk_csum_nr()
                echo -n "[ ok ]"
        fi
        echo -n " - csum  "
-       count=$(ip netns exec $ns2 nstat -as | grep MPTcpExtDataCsumErr | awk '{print $2}')
-       [ -z "$count" ] && count=0
+       count=$(get_counter ${ns2} "MPTcpExtDataCsumErr")
        if [ "$count" != "$csum_ns2" ]; then
                extra_msg="$extra_msg ns2=$count"
        fi
-       if { [ "$count" != $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 0 ]; } ||
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif { [ "$count" != $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 0 ]; } ||
           { [ "$count" -lt $csum_ns2 ] && [ $allow_multi_errors_ns2 -eq 1 ]; }; then
                echo "[fail] got $count data checksum error[s] expected $csum_ns2"
                fail_test
@@ -1251,12 +1267,13 @@ chk_fail_nr()
        fi
 
        printf "%-${nr_blank}s %s" " " "ftx"
-       count=$(ip netns exec $ns_tx nstat -as | grep MPTcpExtMPFailTx | awk '{print $2}')
-       [ -z "$count" ] && count=0
+       count=$(get_counter ${ns_tx} "MPTcpExtMPFailTx")
        if [ "$count" != "$fail_tx" ]; then
                extra_msg="$extra_msg,tx=$count"
        fi
-       if { [ "$count" != "$fail_tx" ] && [ $allow_tx_lost -eq 0 ]; } ||
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif { [ "$count" != "$fail_tx" ] && [ $allow_tx_lost -eq 0 ]; } ||
           { [ "$count" -gt "$fail_tx" ] && [ $allow_tx_lost -eq 1 ]; }; then
                echo "[fail] got $count MP_FAIL[s] TX expected $fail_tx"
                fail_test
@@ -1266,12 +1283,13 @@ chk_fail_nr()
        fi
 
        echo -n " - failrx"
-       count=$(ip netns exec $ns_rx nstat -as | grep MPTcpExtMPFailRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
+       count=$(get_counter ${ns_rx} "MPTcpExtMPFailRx")
        if [ "$count" != "$fail_rx" ]; then
                extra_msg="$extra_msg,rx=$count"
        fi
-       if { [ "$count" != "$fail_rx" ] && [ $allow_rx_lost -eq 0 ]; } ||
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif { [ "$count" != "$fail_rx" ] && [ $allow_rx_lost -eq 0 ]; } ||
           { [ "$count" -gt "$fail_rx" ] && [ $allow_rx_lost -eq 1 ]; }; then
                echo "[fail] got $count MP_FAIL[s] RX expected $fail_rx"
                fail_test
@@ -1303,10 +1321,11 @@ chk_fclose_nr()
        fi
 
        printf "%-${nr_blank}s %s" " " "ctx"
-       count=$(ip netns exec $ns_tx nstat -as | grep MPTcpExtMPFastcloseTx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       [ "$count" != "$fclose_tx" ] && extra_msg="$extra_msg,tx=$count"
-       if [ "$count" != "$fclose_tx" ]; then
+       count=$(get_counter ${ns_tx} "MPTcpExtMPFastcloseTx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$fclose_tx" ]; then
+               extra_msg="$extra_msg,tx=$count"
                echo "[fail] got $count MP_FASTCLOSE[s] TX expected $fclose_tx"
                fail_test
                dump_stats=1
@@ -1315,10 +1334,11 @@ chk_fclose_nr()
        fi
 
        echo -n " - fclzrx"
-       count=$(ip netns exec $ns_rx nstat -as | grep MPTcpExtMPFastcloseRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       [ "$count" != "$fclose_rx" ] && extra_msg="$extra_msg,rx=$count"
-       if [ "$count" != "$fclose_rx" ]; then
+       count=$(get_counter ${ns_rx} "MPTcpExtMPFastcloseRx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$fclose_rx" ]; then
+               extra_msg="$extra_msg,rx=$count"
                echo "[fail] got $count MP_FASTCLOSE[s] RX expected $fclose_rx"
                fail_test
                dump_stats=1
@@ -1349,9 +1369,10 @@ chk_rst_nr()
        fi
 
        printf "%-${nr_blank}s %s" " " "rtx"
-       count=$(ip netns exec $ns_tx nstat -as | grep MPTcpExtMPRstTx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ $count -lt $rst_tx ]; then
+       count=$(get_counter ${ns_tx} "MPTcpExtMPRstTx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ $count -lt $rst_tx ]; then
                echo "[fail] got $count MP_RST[s] TX expected $rst_tx"
                fail_test
                dump_stats=1
@@ -1360,9 +1381,10 @@ chk_rst_nr()
        fi
 
        echo -n " - rstrx "
-       count=$(ip netns exec $ns_rx nstat -as | grep MPTcpExtMPRstRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" -lt "$rst_rx" ]; then
+       count=$(get_counter ${ns_rx} "MPTcpExtMPRstRx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" -lt "$rst_rx" ]; then
                echo "[fail] got $count MP_RST[s] RX expected $rst_rx"
                fail_test
                dump_stats=1
@@ -1383,9 +1405,10 @@ chk_infi_nr()
        local dump_stats
 
        printf "%-${nr_blank}s %s" " " "itx"
-       count=$(ip netns exec $ns2 nstat -as | grep InfiniteMapTx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$infi_tx" ]; then
+       count=$(get_counter ${ns2} "MPTcpExtInfiniteMapTx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$infi_tx" ]; then
                echo "[fail] got $count infinite map[s] TX expected $infi_tx"
                fail_test
                dump_stats=1
@@ -1394,9 +1417,10 @@ chk_infi_nr()
        fi
 
        echo -n " - infirx"
-       count=$(ip netns exec $ns1 nstat -as | grep InfiniteMapRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$infi_rx" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtInfiniteMapRx")
+       if [ -z "$count" ]; then
+               echo "[skip]"
+       elif [ "$count" != "$infi_rx" ]; then
                echo "[fail] got $count infinite map[s] RX expected $infi_rx"
                fail_test
                dump_stats=1
@@ -1428,9 +1452,10 @@ chk_join_nr()
        fi
 
        printf "%03u %-36s %s" "${TEST_COUNT}" "${title}" "syn"
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPJoinSynRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$syn_nr" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtMPJoinSynRx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$syn_nr" ]; then
                echo "[fail] got $count JOIN[s] syn expected $syn_nr"
                fail_test
                dump_stats=1
@@ -1440,9 +1465,10 @@ chk_join_nr()
 
        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
+       count=$(get_counter ${ns2} "MPTcpExtMPJoinSynAckRx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$syn_ack_nr" ]; then
                # 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
@@ -1458,9 +1484,10 @@ chk_join_nr()
        fi
 
        echo -n " - ack"
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPJoinAckRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$ack_nr" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtMPJoinAckRx")
+       if [ -z "$count" ]; then
+               echo "[skip]"
+       elif [ "$count" != "$ack_nr" ]; then
                echo "[fail] got $count JOIN[s] ack expected $ack_nr"
                fail_test
                dump_stats=1
@@ -1492,12 +1519,12 @@ chk_stale_nr()
        local recover_nr
 
        printf "%-${nr_blank}s %-18s" " " "stale"
-       stale_nr=$(ip netns exec $ns nstat -as | grep MPTcpExtSubflowStale | awk '{print $2}')
-       [ -z "$stale_nr" ] && stale_nr=0
-       recover_nr=$(ip netns exec $ns nstat -as | grep MPTcpExtSubflowRecover | awk '{print $2}')
-       [ -z "$recover_nr" ] && recover_nr=0
 
-       if [ $stale_nr -lt $stale_min ] ||
+       stale_nr=$(get_counter ${ns} "MPTcpExtSubflowStale")
+       recover_nr=$(get_counter ${ns} "MPTcpExtSubflowRecover")
+       if [ -z "$stale_nr" ] || [ -z "$recover_nr" ]; then
+               echo "[skip]"
+       elif [ $stale_nr -lt $stale_min ] ||
           { [ $stale_max -gt 0 ] && [ $stale_nr -gt $stale_max ]; } ||
           [ $((stale_nr - recover_nr)) -ne $stale_delta ]; then
                echo "[fail] got $stale_nr stale[s] $recover_nr recover[s], " \
@@ -1533,12 +1560,12 @@ chk_add_nr()
        timeout=$(ip netns exec $ns1 sysctl -n net.mptcp.add_addr_timeout)
 
        printf "%-${nr_blank}s %s" " " "add"
-       count=$(ip netns exec $ns2 nstat -as MPTcpExtAddAddr | grep MPTcpExtAddAddr | awk '{print $2}')
-       [ -z "$count" ] && count=0
-
+       count=$(get_counter ${ns2} "MPTcpExtAddAddr")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
        # if the test configured a short timeout tolerate greater then expected
        # add addrs options, due to retransmissions
-       if [ "$count" != "$add_nr" ] && { [ "$timeout" -gt 1 ] || [ "$count" -lt "$add_nr" ]; }; then
+       elif [ "$count" != "$add_nr" ] && { [ "$timeout" -gt 1 ] || [ "$count" -lt "$add_nr" ]; }; then
                echo "[fail] got $count ADD_ADDR[s] expected $add_nr"
                fail_test
                dump_stats=1
@@ -1547,9 +1574,10 @@ chk_add_nr()
        fi
 
        echo -n " - echo  "
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtEchoAdd | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$echo_nr" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtEchoAdd")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$echo_nr" ]; then
                echo "[fail] got $count ADD_ADDR echo[s] expected $echo_nr"
                fail_test
                dump_stats=1
@@ -1559,9 +1587,10 @@ chk_add_nr()
 
        if [ $port_nr -gt 0 ]; then
                echo -n " - pt "
-               count=$(ip netns exec $ns2 nstat -as | grep MPTcpExtPortAdd | awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$port_nr" ]; then
+               count=$(get_counter ${ns2} "MPTcpExtPortAdd")
+               if [ -z "$count" ]; then
+                       echo "[skip]"
+               elif [ "$count" != "$port_nr" ]; then
                        echo "[fail] got $count ADD_ADDR[s] with a port-number expected $port_nr"
                        fail_test
                        dump_stats=1
@@ -1570,10 +1599,10 @@ chk_add_nr()
                fi
 
                printf "%-${nr_blank}s %s" " " "syn"
-               count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPJoinPortSynRx |
-                       awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$syn_nr" ]; then
+               count=$(get_counter ${ns1} "MPTcpExtMPJoinPortSynRx")
+               if [ -z "$count" ]; then
+                       echo -n "[skip]"
+               elif [ "$count" != "$syn_nr" ]; then
                        echo "[fail] got $count JOIN[s] syn with a different \
                                port-number expected $syn_nr"
                        fail_test
@@ -1583,10 +1612,10 @@ chk_add_nr()
                fi
 
                echo -n " - synack"
-               count=$(ip netns exec $ns2 nstat -as | grep MPTcpExtMPJoinPortSynAckRx |
-                       awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$syn_ack_nr" ]; then
+               count=$(get_counter ${ns2} "MPTcpExtMPJoinPortSynAckRx")
+               if [ -z "$count" ]; then
+                       echo -n "[skip]"
+               elif [ "$count" != "$syn_ack_nr" ]; then
                        echo "[fail] got $count JOIN[s] synack with a different \
                                port-number expected $syn_ack_nr"
                        fail_test
@@ -1596,10 +1625,10 @@ chk_add_nr()
                fi
 
                echo -n " - ack"
-               count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPJoinPortAckRx |
-                       awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$ack_nr" ]; then
+               count=$(get_counter ${ns1} "MPTcpExtMPJoinPortAckRx")
+               if [ -z "$count" ]; then
+                       echo "[skip]"
+               elif [ "$count" != "$ack_nr" ]; then
                        echo "[fail] got $count JOIN[s] ack with a different \
                                port-number expected $ack_nr"
                        fail_test
@@ -1609,10 +1638,10 @@ chk_add_nr()
                fi
 
                printf "%-${nr_blank}s %s" " " "syn"
-               count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMismatchPortSynRx |
-                       awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$mis_syn_nr" ]; then
+               count=$(get_counter ${ns1} "MPTcpExtMismatchPortSynRx")
+               if [ -z "$count" ]; then
+                       echo -n "[skip]"
+               elif [ "$count" != "$mis_syn_nr" ]; then
                        echo "[fail] got $count JOIN[s] syn with a mismatched \
                                port-number expected $mis_syn_nr"
                        fail_test
@@ -1622,10 +1651,10 @@ chk_add_nr()
                fi
 
                echo -n " - ack   "
-               count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMismatchPortAckRx |
-                       awk '{print $2}')
-               [ -z "$count" ] && count=0
-               if [ "$count" != "$mis_ack_nr" ]; then
+               count=$(get_counter ${ns1} "MPTcpExtMismatchPortAckRx")
+               if [ -z "$count" ]; then
+                       echo "[skip]"
+               elif [ "$count" != "$mis_ack_nr" ]; then
                        echo "[fail] got $count JOIN[s] ack with a mismatched \
                                port-number expected $mis_ack_nr"
                        fail_test
@@ -1669,9 +1698,10 @@ chk_rm_nr()
        fi
 
        printf "%-${nr_blank}s %s" " " "rm "
-       count=$(ip netns exec $addr_ns nstat -as | grep MPTcpExtRmAddr | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$rm_addr_nr" ]; then
+       count=$(get_counter ${addr_ns} "MPTcpExtRmAddr")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$rm_addr_nr" ]; then
                echo "[fail] got $count RM_ADDR[s] expected $rm_addr_nr"
                fail_test
                dump_stats=1
@@ -1680,29 +1710,27 @@ chk_rm_nr()
        fi
 
        echo -n " - rmsf  "
-       count=$(ip netns exec $subflow_ns nstat -as | grep MPTcpExtRmSubflow | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ -n "$simult" ]; then
+       count=$(get_counter ${subflow_ns} "MPTcpExtRmSubflow")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ -n "$simult" ]; then
                local cnt suffix
 
-               cnt=$(ip netns exec $addr_ns nstat -as | grep MPTcpExtRmSubflow | awk '{print $2}')
+               cnt=$(get_counter ${addr_ns} "MPTcpExtRmSubflow")
 
                # in case of simult flush, the subflow removal count on each side is
                # unreliable
-               [ -z "$cnt" ] && cnt=0
                count=$((count + cnt))
                [ "$count" != "$rm_subflow_nr" ] && suffix="$count in [$rm_subflow_nr:$((rm_subflow_nr*2))]"
                if [ $count -ge "$rm_subflow_nr" ] && \
                   [ "$count" -le "$((rm_subflow_nr *2 ))" ]; then
-                       echo "[ ok ] $suffix"
+                       echo -n "[ ok ] $suffix"
                else
                        echo "[fail] got $count RM_SUBFLOW[s] expected in range [$rm_subflow_nr:$((rm_subflow_nr*2))]"
                        fail_test
                        dump_stats=1
                fi
-               return
-       fi
-       if [ "$count" != "$rm_subflow_nr" ]; then
+       elif [ "$count" != "$rm_subflow_nr" ]; then
                echo "[fail] got $count RM_SUBFLOW[s] expected $rm_subflow_nr"
                fail_test
                dump_stats=1
@@ -1723,9 +1751,10 @@ chk_prio_nr()
        local dump_stats
 
        printf "%-${nr_blank}s %s" " " "ptx"
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPPrioTx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$mp_prio_nr_tx" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtMPPrioTx")
+       if [ -z "$count" ]; then
+               echo -n "[skip]"
+       elif [ "$count" != "$mp_prio_nr_tx" ]; then
                echo "[fail] got $count MP_PRIO[s] TX expected $mp_prio_nr_tx"
                fail_test
                dump_stats=1
@@ -1734,9 +1763,10 @@ chk_prio_nr()
        fi
 
        echo -n " - prx   "
-       count=$(ip netns exec $ns1 nstat -as | grep MPTcpExtMPPrioRx | awk '{print $2}')
-       [ -z "$count" ] && count=0
-       if [ "$count" != "$mp_prio_nr_rx" ]; then
+       count=$(get_counter ${ns1} "MPTcpExtMPPrioRx")
+       if [ -z "$count" ]; then
+               echo "[skip]"
+       elif [ "$count" != "$mp_prio_nr_rx" ]; then
                echo "[fail] got $count MP_PRIO[s] RX expected $mp_prio_nr_rx"
                fail_test
                dump_stats=1
@@ -1852,7 +1882,7 @@ wait_attempt_fail()
        while [ $time -lt $timeout_ms ]; do
                local cnt
 
-               cnt=$(ip netns exec $ns nstat -as TcpAttemptFails | grep TcpAttemptFails | awk '{print $2}')
+               cnt=$(get_counter ${ns} "TcpAttemptFails")
 
                [ "$cnt" = 1 ] && return 1
                time=$((time + 100))