Introduce an alternative mechanism for wifi drivers to communicate

the channel on which a frame was received.

ieee80211_inputm() was expecting that ic->ic_bss->ni_chan would correspond
to the channel which is currently being scanned. This dates back to older
devices which are manually tuned to the next channel by the driver during
SCAN->SCAN state transitions.

However, this approach is very awkward for drivers which scan across a
whole range of channels in firmware. Such drivers had an ugly workaround
in place which tweaked ni_chan for each received frame.

Introduce a channel number field in the Rx info struct which drivers
can use to indicate the channel on which a frame was received.
If this field is set, net80211 will use it instead of using the current
channel of ic_bss. Use this new mechanism in all affected drivers.

Tested by jmc@, sthen@, and myself on iwm(4) and iwx(4).
Changes to iwn(4) and bwfm(4) are the same mechanical changes to get rid
of the ni_chan tweak, and are therefore expected to work.

ok sthen@ dlg@

1 files changed, 2 insertions, 1 deletions

diff --git a/sys/net80211/ieee80211_node.h b/sys/net80211/ieee80211_node.h
index d03d25669b6..6a9fd5f3d51 100644
--- a/sys/net80211/ieee80211_node.h
+++ b/sys/net80211/ieee80211_node.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ieee80211_node.h,v 1.93 2022/03/19 10:25:09 stsp Exp $	*/
+/*	$OpenBSD: ieee80211_node.h,v 1.94 2022/03/20 12:01:58 stsp Exp $	*/
 /*	$NetBSD: ieee80211_node.h,v 1.9 2004/04/30 22:57:32 dyoung Exp $	*/
 
 /*-
@@ -192,6 +192,7 @@ struct ieee80211_rxinfo {
 	u_int32_t		rxi_flags;
 	u_int32_t		rxi_tstamp;
 	int			rxi_rssi;
+	uint8_t			rxi_chan;
 };
 #define IEEE80211_RXI_HWDEC		0x00000001
 #define IEEE80211_RXI_AMPDU_DONE	0x00000002