From 88290e74196d2755c0e925f35e38f670ccb172b7 Mon Sep 17 00:00:00 2001
From: stsp <stsp@openbsd.org>
Date: Mon, 11 Oct 2021 09:02:01 +0000
Subject: [PATCH] Monitor 20/40 MHz channel width changes in beacons sent by
 our access point and notify drivers when the channel width has changed.

---
 sys/net80211/ieee80211_input.c | 23 ++++++++++++++++++++++-
 sys/net80211/ieee80211_var.h   |  3 ++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c
index 99699b933a0..888a39c43dd 100644
--- a/sys/net80211/ieee80211_input.c
+++ b/sys/net80211/ieee80211_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_input.c,v 1.238 2021/09/03 12:39:43 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_input.c,v 1.239 2021/10/11 09:02:01 stsp Exp $	*/
 
 /*-
  * Copyright (c) 2001 Atsushi Onoe
@@ -1857,6 +1857,27 @@ ieee80211_recv_probe_resp(struct ieee80211com *ic, struct mbuf *m,
 		if (updateprot && ic->ic_updateprot != NULL)
 			ic->ic_updateprot(ic);
 
+		/*
+		 * Check if 40MHz channel mode has changed since last beacon.
+		 */
+		if (htop && (ic->ic_bss->ni_flags & IEEE80211_NODE_HT) &&
+		    (ic->ic_htcaps & IEEE80211_HTCAP_CBW20_40)) {
+			uint8_t chw_last, chw, sco_last, sco;
+			chw_last = (ic->ic_bss->ni_htop0 & IEEE80211_HTOP0_CHW);
+			chw = (ni->ni_htop0 & IEEE80211_HTOP0_CHW);
+			sco_last =
+			    ((ic->ic_bss->ni_htop0 & IEEE80211_HTOP0_SCO_MASK)
+			    >> IEEE80211_HTOP0_SCO_SHIFT);
+			sco = ((ni->ni_htop0 & IEEE80211_HTOP0_SCO_MASK) >>
+			    IEEE80211_HTOP0_SCO_SHIFT);
+			ic->ic_bss->ni_htop0 = ni->ni_htop0;
+			if (chw_last != chw || sco_last != sco) {
+				if (ic->ic_updatechan != NULL)
+					ic->ic_updatechan(ic);
+			}
+		} else if (htop)
+			ic->ic_bss->ni_htop0 = ni->ni_htop0;
+
 		/*
 		 * Check if AP short slot time setting has changed
 		 * since last beacon and give the driver a chance to
diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index a1b9660670f..174da137a22 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_var.h,v 1.106 2021/10/11 09:01:06 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_var.h,v 1.107 2021/10/11 09:02:01 stsp Exp $	*/
 /*	$NetBSD: ieee80211_var.h,v 1.7 2004/05/06 03:07:10 dyoung Exp $	*/
 
 /*-
@@ -246,6 +246,7 @@ struct ieee80211com {
 	void			(*ic_ampdu_rx_stop)(struct ieee80211com *,
 				    struct ieee80211_node *, u_int8_t);
 	void			(*ic_updateprot)(struct ieee80211com *);
+	void			(*ic_updatechan)(struct ieee80211com *);
 	int			(*ic_bgscan_start)(struct ieee80211com *);
 	struct timeout		ic_bgscan_timeout;
 	uint32_t		ic_bgscan_fail;
-- 
2.20.1