[PATCH mptcp-next RFC v5 1/3] mptcp: add MPFailFallback MIB counter

[Chenguang Zhao <chenguang.zhao@linux.dev>]

From: Chenguang Zhao <zhaochenguang@kylinos.cn>

Track fallback triggered by MP_FAIL reception.

Signed-off-by: Chenguang Zhao <zhaochenguang@kylinos.cn>
---
 net/mptcp/mib.c | 1 +
 net/mptcp/mib.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/net/mptcp/mib.c b/net/mptcp/mib.c
index 608cb568897c..e1211ad621c9 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -91,6 +91,7 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("DssReset", MPTCP_MIB_DSSRESET),
 	SNMP_MIB_ITEM("SimultConnectFallback", MPTCP_MIB_SIMULTCONNFALLBACK),
 	SNMP_MIB_ITEM("FallbackFailed", MPTCP_MIB_FALLBACKFAILED),
+	SNMP_MIB_ITEM("MPFailFallback", MPTCP_MIB_MPFAILFALLBACK),
 	SNMP_MIB_ITEM("WinProbe", MPTCP_MIB_WINPROBE),
 	SNMP_MIB_ITEM("BacklogDrop", MPTCP_MIB_BACKLOGDROP),
 	SNMP_MIB_ITEM("RcvPruned", MPTCP_MIB_RCVPRUNED),
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 1ebdb55e9534..b006fc8cc848 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -94,6 +94,7 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_DSSRESET,		/* MP_RST: bad data mapping */
 	MPTCP_MIB_SIMULTCONNFALLBACK,	/* Simultaneous connect */
 	MPTCP_MIB_FALLBACKFAILED,	/* Can't fallback due to msk status */
+	MPTCP_MIB_MPFAILFALLBACK,	/* Fallback after MP_FAIL received */
 	MPTCP_MIB_WINPROBE,		/* MPTCP-level zero window probe */
 	MPTCP_MIB_BACKLOGDROP,		/* Backlog over memory limit */
 	MPTCP_MIB_RCVPRUNED,		/* Dropped due to memory constraints */
-- 
2.25.1