Commit 7a1b3490 authored by Davide Caratti's avatar Davide Caratti Committed by Jakub Kicinski

mptcp: don't account accept() of non-MPC client as fallback to TCP

Current MPTCP servers increment MPTcpExtMPCapableFallbackACK when they
accept non-MPC connections. As reported by Christoph, this is "surprising"
because the counter might become greater than MPTcpExtMPCapableSYNRX.

MPTcpExtMPCapableFallbackACK counter's name suggests it should only be
incremented when a connection was seen using MPTCP options, then a
fallback to TCP has been done. Let's do that by incrementing it when
the subflow context of an inbound MPC connection attempt is dropped.
Also, update mptcp_connect.sh kselftest, to ensure that the
above MIB does not increment in case a pure TCP client connects to a
MPTCP server.

Fixes: fc518953 ("mptcp: add and use MIB counter infrastructure")
Cc: stable@vger.kernel.org
Reported-by: default avatarChristoph Paasch <cpaasch@apple.com>
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/449Signed-off-by: default avatarDavide Caratti <dcaratti@redhat.com>
Reviewed-by: default avatarMat Martineau <martineau@kernel.org>
Reviewed-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Signed-off-by: default avatarMatthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://lore.kernel.org/r/20240329-upstream-net-20240329-fallback-mib-v1-1-324a8981da48@kernel.orgSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent fcf4692f
...@@ -3937,8 +3937,6 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock, ...@@ -3937,8 +3937,6 @@ static int mptcp_stream_accept(struct socket *sock, struct socket *newsock,
mptcp_set_state(newsk, TCP_CLOSE); mptcp_set_state(newsk, TCP_CLOSE);
} }
} else { } else {
MPTCP_INC_STATS(sock_net(ssk),
MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
tcpfallback: tcpfallback:
newsk->sk_kern_sock = kern; newsk->sk_kern_sock = kern;
lock_sock(newsk); lock_sock(newsk);
......
...@@ -905,6 +905,8 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk, ...@@ -905,6 +905,8 @@ static struct sock *subflow_syn_recv_sock(const struct sock *sk,
return child; return child;
fallback: fallback:
if (fallback)
SUBFLOW_REQ_INC_STATS(req, MPTCP_MIB_MPCAPABLEPASSIVEFALLBACK);
mptcp_subflow_drop_ctx(child); mptcp_subflow_drop_ctx(child);
return child; return child;
} }
......
...@@ -383,12 +383,14 @@ do_transfer() ...@@ -383,12 +383,14 @@ do_transfer()
local stat_cookierx_last local stat_cookierx_last
local stat_csum_err_s local stat_csum_err_s
local stat_csum_err_c local stat_csum_err_c
local stat_tcpfb_last_l
stat_synrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX") stat_synrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX")
stat_ackrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX") stat_ackrx_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")
stat_cookietx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent") stat_cookietx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent")
stat_cookierx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv") stat_cookierx_last=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv")
stat_csum_err_s=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtDataCsumErr") stat_csum_err_s=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtDataCsumErr")
stat_csum_err_c=$(mptcp_lib_get_counter "${connector_ns}" "MPTcpExtDataCsumErr") stat_csum_err_c=$(mptcp_lib_get_counter "${connector_ns}" "MPTcpExtDataCsumErr")
stat_tcpfb_last_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableFallbackACK")
timeout ${timeout_test} \ timeout ${timeout_test} \
ip netns exec ${listener_ns} \ ip netns exec ${listener_ns} \
...@@ -457,11 +459,13 @@ do_transfer() ...@@ -457,11 +459,13 @@ do_transfer()
local stat_cookietx_now local stat_cookietx_now
local stat_cookierx_now local stat_cookierx_now
local stat_ooo_now local stat_ooo_now
local stat_tcpfb_now_l
stat_synrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX") stat_synrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableSYNRX")
stat_ackrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX") stat_ackrx_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableACKRX")
stat_cookietx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent") stat_cookietx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesSent")
stat_cookierx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv") stat_cookierx_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtSyncookiesRecv")
stat_ooo_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtTCPOFOQueue") stat_ooo_now=$(mptcp_lib_get_counter "${listener_ns}" "TcpExtTCPOFOQueue")
stat_tcpfb_now_l=$(mptcp_lib_get_counter "${listener_ns}" "MPTcpExtMPCapableFallbackACK")
expect_synrx=$((stat_synrx_last_l)) expect_synrx=$((stat_synrx_last_l))
expect_ackrx=$((stat_ackrx_last_l)) expect_ackrx=$((stat_ackrx_last_l))
...@@ -508,6 +512,11 @@ do_transfer() ...@@ -508,6 +512,11 @@ do_transfer()
fi fi
fi fi
if [ ${stat_ooo_now} -eq 0 ] && [ ${stat_tcpfb_last_l} -ne ${stat_tcpfb_now_l} ]; then
mptcp_lib_pr_fail "unexpected fallback to TCP"
rets=1
fi
if [ $cookies -eq 2 ];then if [ $cookies -eq 2 ];then
if [ $stat_cookietx_last -ge $stat_cookietx_now ] ;then if [ $stat_cookietx_last -ge $stat_cookietx_now ] ;then
extra+=" WARN: CookieSent: did not advance" extra+=" WARN: CookieSent: did not advance"
......
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