[PATCH v2 mptcp-next 6/8] mptcp: add mibs for stale subflows processing

[Paolo Abeni <pabeni@redhat.com>]

This allows monitoring exceptional events like
active backup scenarios.

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
---
 net/mptcp/mib.c        | 2 ++
 net/mptcp/mib.h        | 2 ++
 net/mptcp/pm.c         | 2 ++
 net/mptcp/pm_netlink.c | 1 +
 net/mptcp/protocol.c   | 1 +
 5 files changed, 8 insertions(+)

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index ff2cc0e3273d..3a7c4e7b2d79 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -45,6 +45,8 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("MPPrioTx", MPTCP_MIB_MPPRIOTX),
 	SNMP_MIB_ITEM("MPPrioRx", MPTCP_MIB_MPPRIORX),
 	SNMP_MIB_ITEM("RcvPruned", MPTCP_MIB_RCVPRUNED),
+	SNMP_MIB_ITEM("SubflowStale", MPTCP_MIB_SUBFLOWSTALE),
+	SNMP_MIB_ITEM("SubflowRecover", MPTCP_MIB_SUBFLOWRECOVER),
 	SNMP_MIB_SENTINEL
 };
 
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 0663cb12b448..8ec16c991aac 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -38,6 +38,8 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_MPPRIOTX,		/* Transmit a MP_PRIO */
 	MPTCP_MIB_MPPRIORX,		/* Received a MP_PRIO */
 	MPTCP_MIB_RCVPRUNED,		/* Incoming packet dropped due to memory limit */
+	MPTCP_MIB_SUBFLOWSTALE,		/* Subflows entered 'stale' status */
+	MPTCP_MIB_SUBFLOWRECOVER,	/* Subflows returned to active status after being stale */
 	__MPTCP_MIB_MAX
 };
 
diff --git a/net/mptcp/pm.c b/net/mptcp/pm.c
index d8a85fe92360..0ed3e565f8f8 100644
--- a/net/mptcp/pm.c
+++ b/net/mptcp/pm.c
@@ -10,6 +10,8 @@
 #include <net/mptcp.h>
 #include "protocol.h"
 
+#include "mib.h"
+
 /* path manager command handlers */
 
 int mptcp_pm_announce_addr(struct mptcp_sock *msk,
diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index eb1f5cf89423..3d4fa2dd2cea 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -924,6 +924,7 @@ void mptcp_pm_nl_subflow_chk_stale(const struct mptcp_sock *msk, struct sock *ss
 			if (!tcp_rtx_and_write_queues_empty(ssk)) {
 				subflow->stale = 1;
 				push = __mptcp_retransmit_pending_data(sk);
+				MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_SUBFLOWSTALE);
 			}
 			unlock_sock_fast(ssk, slow);
 
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e936b88d340d..8eb2626503d7 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1397,6 +1397,7 @@ void mptcp_subflow_set_active(struct mptcp_subflow_context *subflow)
 		return;
 
 	subflow->stale = 0;
+	MPTCP_INC_STATS(sock_net(mptcp_subflow_tcp_sock(subflow)), MPTCP_MIB_SUBFLOWRECOVER);
 }
 
 bool mptcp_subflow_active(struct mptcp_subflow_context *subflow)
-- 
2.26.3