--- /dev/null
+From c7cca9b08f3e1e49c4a4a59ec66c47d91448e6ae Mon Sep 17 00:00:00 2001
+From: Jouni Malinen <j@w1.fi>
+Date: Sat, 13 Feb 2021 23:59:28 +0200
+Subject: [PATCH] nl80211: Ignore 4addr mode enabling error if it was already
+ enabled
+
+nl80211_set_4addr_mode() could fail when trying to enable 4addr mode on
+an interface that is in a bridge and has 4addr mode already enabled.
+This operation would not have been necessary in the first place and this
+failure results in disconnecting, e.g., when roaming from one backhaul
+BSS to another BSS with Multi AP.
+
+Avoid this issue by ignoring the nl80211 command failure in the case
+where 4addr mode is being enabled while it has already been enabled.
+
+Signed-off-by: Jouni Malinen <j@w1.fi>
+---
+ src/drivers/driver_nl80211.c | 23 +++++++++++++++++++++++
+ 1 file changed, 23 insertions(+)
+
+diff --git a/src/drivers/driver_nl80211.c b/src/drivers/driver_nl80211.c
+index 72189da24..011a15e68 100644
+--- a/src/drivers/driver_nl80211.c
++++ b/src/drivers/driver_nl80211.c
+@@ -617,6 +617,7 @@ struct wiphy_idx_data {
+ int wiphy_idx;
+ enum nl80211_iftype nlmode;
+ u8 *macaddr;
++ u8 use_4addr;
+ };
+
+
+@@ -639,6 +640,9 @@ static int netdev_info_handler(struct nl_msg *msg, void *arg)
+ os_memcpy(info->macaddr, nla_data(tb[NL80211_ATTR_MAC]),
+ ETH_ALEN);
+
++ if (tb[NL80211_ATTR_4ADDR])
++ info->use_4addr = nla_get_u8(tb[NL80211_ATTR_4ADDR]);
++
+ return NL_SKIP;
+ }
+
+@@ -691,6 +695,20 @@ static int nl80211_get_macaddr(struct i802_bss *bss)
+ }
+
+
++static int nl80211_get_4addr(struct i802_bss *bss)
++{
++ struct nl_msg *msg;
++ struct wiphy_idx_data data = {
++ .use_4addr = 0,
++ };
++
++ if (!(msg = nl80211_cmd_msg(bss, 0, NL80211_CMD_GET_INTERFACE)) ||
++ send_and_recv_msgs(bss->drv, msg, netdev_info_handler, &data))
++ return -1;
++ return data.use_4addr;
++}
++
++
+ static int nl80211_register_beacons(struct wpa_driver_nl80211_data *drv,
+ struct nl80211_wiphy_data *w)
+ {
+@@ -11482,6 +11500,11 @@ static int nl80211_set_4addr_mode(void *priv, const char *bridge_ifname,
+
+ ret = send_and_recv_msgs(drv, msg, NULL, NULL);
+ msg = NULL;
++ if (ret && val && nl80211_get_4addr(bss) == 1) {
++ wpa_printf(MSG_DEBUG,
++ "nl80211: 4addr mode was already enabled");
++ ret = 0;
++ }
+ if (!ret) {
+ if (bridge_ifname[0] && val &&
+ i802_check_bridge(drv, bss, bridge_ifname, bss->ifname) < 0)
+--
+2.29.2
+