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Message-Id: <20250907-net-next-mptcp-add_addr-retrans-adapt-v1-2-824cc805772b@kernel.org>
Date: Sun, 07 Sep 2025 17:32:43 +0200
From: "Matthieu Baerts (NGI0)" <matttbe@...nel.org>
To: mptcp@...ts.linux.dev, Mat Martineau <martineau@...nel.org>,
Geliang Tang <geliang@...nel.org>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>,
Jonathan Corbet <corbet@....net>, Shuah Khan <shuah@...nel.org>
Cc: netdev@...r.kernel.org, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org,
"Matthieu Baerts (NGI0)" <matttbe@...nel.org>
Subject: [PATCH net-next 2/3] selftests: mptcp: join: tolerate more
ADD_ADDR
ADD_ADDR can be retransmitted, and with, the parent commit, these
retransmissions can be sent quicker: from 2 minutes to less than one
second.
To avoid false positives where retransmitted ADD_ADDR causes higher
counters than expected, it is required to be more tolerant. Errors are
now only reported when fewer ADD_ADDRs have been sent/received, except
if no ADD_ADDR are expected.
Before the parent commit, the tolerance was present for each tests where
the ADD_ADDR could be retransmitted in a reasonable time (1 sec). Now
that all tests can have retransmitted ADD_ADDR, it is normal to apply
the same tolerance for all tests.
An alternative could be to disable the ADD_ADDR retransmissions by
default, but that's changing the default kernel behaviour. Plus,
ADD_ADDR retransmissions can be required for some tests. To avoid adding
exceptions to many tests, it seems better to increase the tolerance.
Later, we could add a new MIB counter to identify the ADD_ADDR
retransmissions, and remove the tolerance when this counter is
available.
Reviewed-by: Geliang Tang <geliang@...nel.org>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@...nel.org>
---
tools/testing/selftests/net/mptcp/mptcp_join.sh | 19 +++++++------------
1 file changed, 7 insertions(+), 12 deletions(-)
diff --git a/tools/testing/selftests/net/mptcp/mptcp_join.sh b/tools/testing/selftests/net/mptcp/mptcp_join.sh
index 2f046167a0b6cc6fb5531a033d8d95c9ea399cf9..e9e11a9e60fd5374c8a98c3b7159ccbca8053030 100755
--- a/tools/testing/selftests/net/mptcp/mptcp_join.sh
+++ b/tools/testing/selftests/net/mptcp/mptcp_join.sh
@@ -358,6 +358,7 @@ reset_with_add_addr_timeout()
tables="${ip6tables}"
fi
+ # set a maximum, to avoid too long timeout with exponential backoff
ip netns exec $ns1 sysctl -q net.mptcp.add_addr_timeout=1
if ! ip netns exec $ns2 $tables -A OUTPUT -p tcp \
@@ -1669,7 +1670,6 @@ chk_add_nr()
local tx=""
local rx=""
local count
- local timeout
if [[ $ns_invert = "invert" ]]; then
ns_tx=$ns2
@@ -1678,15 +1678,13 @@ chk_add_nr()
rx=" server"
fi
- timeout=$(ip netns exec ${ns_tx} sysctl -n net.mptcp.add_addr_timeout)
-
print_check "add addr rx${rx}"
count=$(mptcp_lib_get_counter ${ns_rx} "MPTcpExtAddAddr")
if [ -z "$count" ]; then
print_skip
- # if the test configured a short timeout tolerate greater then expected
- # add addrs options, due to retransmissions
- elif [ "$count" != "$add_nr" ] && { [ "$timeout" -gt 1 ] || [ "$count" -lt "$add_nr" ]; }; then
+ # Tolerate more ADD_ADDR then expected (if any), due to retransmissions
+ elif [ "$count" != "$add_nr" ] &&
+ { [ "$add_nr" -eq 0 ] || [ "$count" -lt "$add_nr" ]; }; then
fail_test "got $count ADD_ADDR[s] expected $add_nr"
else
print_ok
@@ -1774,18 +1772,15 @@ chk_add_tx_nr()
{
local add_tx_nr=$1
local echo_tx_nr=$2
- local timeout
local count
- timeout=$(ip netns exec $ns1 sysctl -n net.mptcp.add_addr_timeout)
-
print_check "add addr tx"
count=$(mptcp_lib_get_counter ${ns1} "MPTcpExtAddAddrTx")
if [ -z "$count" ]; then
print_skip
- # if the test configured a short timeout tolerate greater then expected
- # add addrs options, due to retransmissions
- elif [ "$count" != "$add_tx_nr" ] && { [ "$timeout" -gt 1 ] || [ "$count" -lt "$add_tx_nr" ]; }; then
+ # Tolerate more ADD_ADDR then expected (if any), due to retransmissions
+ elif [ "$count" != "$add_tx_nr" ] &&
+ { [ "$add_tx_nr" -eq 0 ] || [ "$count" -lt "$add_tx_nr" ]; }; then
fail_test "got $count ADD_ADDR[s] TX, expected $add_tx_nr"
else
print_ok
--
2.51.0
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