From 665ec41339659bef7f643c6df7aab034be0523ed Mon Sep 17 00:00:00 2001
From: zmw12306 <zmw12306@gmail.com>
Date: Sun, 7 Apr 2024 16:19:38 -0400
Subject: [PATCH] bfdd:  add check for flag M

Signed-off-by: zmw12306 <zmw12306@gmail.com>
---
 bfdd/bfd.h        | 2 ++
 bfdd/bfd_packet.c | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/bfdd/bfd.h b/bfdd/bfd.h
index 5451e66c23df..c6dc0d613714 100644
--- a/bfdd/bfd.h
+++ b/bfdd/bfd.h
@@ -89,6 +89,8 @@ struct bfd_echo_pkt {
 #define BFD_CBIT 0x08
 #define BFD_ABIT 0x04
 #define BFD_DEMANDBIT 0x02
+#define BFD_MBIT	      0x01
+#define BFD_GETMBIT(flags)    (flags & BFD_MBIT)
 #define BFD_SETDEMANDBIT(flags, val)                                           \
 	{                                                                      \
 		if ((val))                                                     \
diff --git a/bfdd/bfd_packet.c b/bfdd/bfd_packet.c
index 311ce4d37905..dadf9c25d756 100644
--- a/bfdd/bfd_packet.c
+++ b/bfdd/bfd_packet.c
@@ -862,6 +862,12 @@ void bfd_recv_cb(struct event *t)
 		return;
 	}
 
+	if (BFD_GETMBIT(cp->flags)) {
+		cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
+			 "detect non-zero Multipoint (M) flag");
+		return;
+	}
+
 	if (cp->discrs.my_discr == 0) {
 		cp_debug(is_mhop, &peer, &local, ifindex, vrfid,
 			 "'my discriminator' is zero");