[RFC 6/6] wifi: mac80211: check vif radio_mask for monitor mode rx

[Felix Fietkau <nbd@xxxxxxxx>]

When restricting a monitor vif to only operate on a specific set of radios,
filter out rx packets belonging to other radios. This only works if drivers
fill in radio_valid and radio_idx in the rx status.

Signed-off-by: Felix Fietkau <nbd@xxxxxxxx>
---
 include/net/mac80211.h |  3 ++-
 net/mac80211/rx.c      | 58 +++++++++++++++++++++++--------------------
 2 files changed, 35 insertions(+), 26 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 7a5418713dfc..6222f4f44ac2 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -1619,6 +1619,8 @@ enum mac80211_rx_encoding {
  * @ampdu_reference: A-MPDU reference number, must be a different value for
  *	each A-MPDU but the same for each subframe within one A-MPDU
  * @zero_length_psdu_type: radiotap type of the 0-length PSDU
+ * @radio_valid: if the index of the radio in radio_idx is valid.
+ * @radio_idx: index of the wiphy radio that the frame was received on.
  * @link_valid: if the link which is identified by @link_id is valid. This flag
  *	is set only when connection is MLO.
  * @link_id: id of the link used to receive the packet. This is used along with
@@ -1656,6 +1658,7 @@ struct ieee80211_rx_status {
 	u8 chains;
 	s8 chain_signal[IEEE80211_MAX_CHAINS];
 	u8 zero_length_psdu_type;
+	u8 radio_valid:1, radio_idx:5;
 	u8 link_valid:1, link_id:4;
 };
 
diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c
index 718f02f0a181..de4196fa3eb5 100644
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -762,8 +762,8 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 		     struct ieee80211_rate *rate)
 {
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(origskb);
-	struct ieee80211_sub_if_data *sdata;
-	struct sk_buff *monskb = NULL;
+	struct ieee80211_sub_if_data *sdata, *prev_sdata = NULL;
+	struct sk_buff *skb, *monskb = NULL;
 	int present_fcs_len = 0;
 	unsigned int rtap_space = 0;
 	struct ieee80211_sub_if_data *monitor_sdata =
@@ -837,40 +837,46 @@ ieee80211_rx_monitor(struct ieee80211_local *local, struct sk_buff *origskb,
 	ieee80211_handle_mu_mimo_mon(monitor_sdata, origskb, rtap_space);
 
 	list_for_each_entry_rcu(sdata, &local->mon_list, u.mntr.list) {
-		bool last_monitor = list_is_last(&sdata->u.mntr.list,
-						 &local->mon_list);
+		if (status->radio_valid &&
+		    !(sdata->wdev.radio_mask & BIT(status->radio_idx)))
+			continue;
+
+		if (!prev_sdata) {
+			prev_sdata = sdata;
+			continue;
+		}
 
 		if (!monskb)
 			monskb = ieee80211_make_monitor_skb(local, &origskb,
 							    rate, rtap_space,
-							    only_monitor &&
-							    last_monitor);
+							    false);
+		if (!monskb)
+			continue;
 
-		if (monskb) {
-			struct sk_buff *skb;
+		skb = skb_clone(monskb, GFP_ATOMIC);
+		if (!skb)
+			continue;
 
-			if (last_monitor) {
-				skb = monskb;
-				monskb = NULL;
-			} else {
-				skb = skb_clone(monskb, GFP_ATOMIC);
-			}
+		skb->dev = prev_sdata->dev;
+		dev_sw_netstats_rx_add(skb->dev, skb->len);
+		netif_receive_skb(skb);
+		prev_sdata = sdata;
+	}
 
-			if (skb) {
-				skb->dev = sdata->dev;
-				dev_sw_netstats_rx_add(skb->dev, skb->len);
-				netif_receive_skb(skb);
-			}
+	if (prev_sdata) {
+		if (monskb)
+			skb = monskb;
+		else
+			skb = ieee80211_make_monitor_skb(local, &origskb,
+							 rate, rtap_space,
+							 only_monitor);
+		if (skb) {
+			skb->dev = prev_sdata->dev;
+			dev_sw_netstats_rx_add(skb->dev, skb->len);
+			netif_receive_skb(skb);
 		}
-
-		if (last_monitor)
-			break;
 	}
 
-	/* this happens if last_monitor was erroneously false */
-	dev_kfree_skb(monskb);
-
-	/* ditto */
 	if (!origskb)
 		return NULL;
 
-- 
git-series 0.9.1