[PATCH wireless-next 1/2] wifi: mac80211: set band information for NULL packets only for non-MLO stations

[Suraj P Kizhakkethil <suraj.kizhakkethil@oss.qualcomm.com>]

Currently, when sending a NULL packet to probe a station, the band
information is derived from the chanctx_conf in the mac80211 vif's
bss_conf. However, for MLO, chanctx_conf is not assigned to the vif's
bss_conf; instead it is assigned on a per-link basis. As a result,
for MLO, sending a NULL packet to probe will trigger a warning.

WARNING: net/mac80211/cfg.c:4593 at ieee80211_probe_client+0x1a8/0x1e0 [mac80211], CPU#2: hostapd/241
Call trace:
 ieee80211_probe_client+0x1a8/0x1e0 [mac80211] (P)
 nl80211_probe_client+0xac/0x170 [cfg80211]
 genl_family_rcv_msg_doit+0xc8/0x134
 genl_rcv_msg+0x200/0x280
 netlink_rcv_skb+0x38/0xfc
 genl_rcv+0x34/0x48
 netlink_unicast+0x228/0x334
 netlink_sendmsg+0x158/0x364
 ____sys_sendmsg+0x1f4/0x21c
 ___sys_sendmsg+0x98/0xc0
 __sys_sendmsg+0x74/0xd0
 __arm64_sys_sendmsg+0x20/0x28
 invoke_syscall.constprop.0+0x4c/0xd0
 do_el0_svc+0x3c/0xd0
 el0_svc+0x28/0xb8
 el0t_64_sync_handler+0x98/0xdc
 el0t_64_sync+0x154/0x158
---[ end trace 0000000000000000 ]---

For NULL packets sent to probe stations, set the band information only
for non-MLD case, since MLD transmissions does not rely on band. For
MLD connections, set the link ID as unspecified to allow the driver
to select the appropriate link. The case specific to non-MLO stations
connected to an MLD AP will be addressed in a follow up patch.

Signed-off-by: Suraj P Kizhakkethil <suraj.kizhakkethil@oss.qualcomm.com>
---
 net/mac80211/cfg.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index b51c2c8584ae..9554b25b8fc6 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -4609,12 +4609,17 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
 
 	qos = sta->sta.wme;
 
-	chanctx_conf = rcu_dereference(sdata->vif.bss_conf.chanctx_conf);
-	if (WARN_ON(!chanctx_conf)) {
-		ret = -EINVAL;
-		goto unlock;
+	if (ieee80211_vif_is_mld(&sdata->vif)) {
+		/* MLD transmissions must not rely on the band */
+		band = 0;
+	} else {
+		chanctx_conf = rcu_dereference(sdata->vif.bss_conf.chanctx_conf);
+		if (WARN_ON(!chanctx_conf)) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+		band = chanctx_conf->def.chan->band;
 	}
-	band = chanctx_conf->def.chan->band;
 
 	if (qos) {
 		fc = cpu_to_le16(IEEE80211_FTYPE_DATA |
@@ -4651,6 +4656,9 @@ static int ieee80211_probe_client(struct wiphy *wiphy, struct net_device *dev,
 		       IEEE80211_TX_INTFL_NL80211_FRAME_TX;
 	info->band = band;
 
+	if (ieee80211_vif_is_mld(&sdata->vif))
+		info->control.flags |= IEEE80211_TX_CTRL_MLO_LINK_UNSPEC;
+
 	skb_set_queue_mapping(skb, IEEE80211_AC_VO);
 	skb->priority = 7;
 	if (qos)
-- 
2.34.1