[PATCH mptcp-next RFC v4 1/2] mptcp: add MPFailFallback MIB

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

From: Chenguang Zhao <zhaochenguang@kylinos.cn>

Add a counter for TCP fallback after accepting MP_FAIL.

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..648d4dbca764 100644
--- a/net/mptcp/mib.c
+++ b/net/mptcp/mib.c
@@ -88,6 +88,7 @@ static const struct snmp_mib mptcp_snmp_list[] = {
 	SNMP_MIB_ITEM("MD5SigFallback", MPTCP_MIB_MD5SIGFALLBACK),
 	SNMP_MIB_ITEM("MD5SigReset", MPTCP_MIB_MD5SIGRESET),
 	SNMP_MIB_ITEM("DssFallback", MPTCP_MIB_DSSFALLBACK),
+	SNMP_MIB_ITEM("MPFailFallback", MPTCP_MIB_MPFAILFALLBACK),
 	SNMP_MIB_ITEM("DssReset", MPTCP_MIB_DSSRESET),
 	SNMP_MIB_ITEM("SimultConnectFallback", MPTCP_MIB_SIMULTCONNFALLBACK),
 	SNMP_MIB_ITEM("FallbackFailed", MPTCP_MIB_FALLBACKFAILED),
diff --git a/net/mptcp/mib.h b/net/mptcp/mib.h
index 1ebdb55e9534..075e21e20a80 100644
--- a/net/mptcp/mib.h
+++ b/net/mptcp/mib.h
@@ -91,6 +91,7 @@ enum linux_mptcp_mib_field {
 	MPTCP_MIB_MD5SIGFALLBACK,	/* Conflicting TCP option enabled */
 	MPTCP_MIB_MD5SIGRESET,		/* MP_RST: MD5SIG enabled on listener */
 	MPTCP_MIB_DSSFALLBACK,		/* Bad or missing DSS */
+	MPTCP_MIB_MPFAILFALLBACK,	/* Received MP_FAIL, fallback */
 	MPTCP_MIB_DSSRESET,		/* MP_RST: bad data mapping */
 	MPTCP_MIB_SIMULTCONNFALLBACK,	/* Simultaneous connect */
 	MPTCP_MIB_FALLBACKFAILED,	/* Can't fallback due to msk status */
-- 
2.25.1