From f65dedbb8f3bd8a0ec69a02f63f62f339a791423 Mon Sep 17 00:00:00 2001
From: Yu Watanabe <watanabe.yu+github@gmail.com>
Date: Aug 06 2021 14:40:58 +0000
Subject: sd-netlink: always append new bridge FDB entries


This partially reverts 192a9d95ea3e058afd824d38a9cea16ad0a84a57 (#19432).

Fixes #20305.

(cherry picked from commit 74c1ab841fbad9d4f237c819577fcd1d46a072b6)

---

diff --git a/src/libsystemd/sd-netlink/rtnl-message.c b/src/libsystemd/sd-netlink/rtnl-message.c
index e771b95..7f83bf5 100644
--- a/src/libsystemd/sd-netlink/rtnl-message.c
+++ b/src/libsystemd/sd-netlink/rtnl-message.c
@@ -443,8 +443,12 @@ int sd_rtnl_message_new_neigh(sd_netlink *rtnl, sd_netlink_message **ret, uint16
         if (r < 0)
                 return r;
 
-        if (nlmsg_type == RTM_NEWNEIGH)
-                (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+        if (nlmsg_type == RTM_NEWNEIGH) {
+                if (ndm_family == AF_BRIDGE)
+                        (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_APPEND;
+                else
+                        (*ret)->hdr->nlmsg_flags |= NLM_F_CREATE | NLM_F_REPLACE;
+        }
 
         ndm = NLMSG_DATA((*ret)->hdr);