From: Paolo Abeni <pabeni@xxxxxxxxxx> commit f73c1194634506ab60af0debef04671fc431a435 upstream. 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@xxxxxxxxxxxx> Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Mat Martineau <mathew.j.martineau@xxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/mptcp/mib.c | 2 ++ net/mptcp/mib.h | 2 ++ net/mptcp/pm.c | 8 ++++++-- 3 files changed, 10 insertions(+), 2 deletions(-) --- a/net/mptcp/mib.c +++ b/net/mptcp/mib.c @@ -35,12 +35,14 @@ static const struct snmp_mib mptcp_snmp_ 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), --- 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 */ --- a/net/mptcp/pm.c +++ b/net/mptcp/pm.c @@ -194,6 +194,8 @@ void mptcp_pm_add_addr_received(struct m 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); @@ -234,8 +236,10 @@ void mptcp_pm_rm_addr_received(struct mp 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); } Patches currently in stable-queue which might be from pabeni@xxxxxxxxxx are queue-5.15/selftests-mptcp-be-more-conservative-with-cookie-mpj-limits.patch queue-5.15/selftests-mptcp-fix-diag-instability.patch queue-5.15/mptcp-add-mibs-counter-for-ignored-incoming-options.patch queue-5.15/mptcp-fix-race-in-incoming-add_addr-option-processing.patch