wifi: mac80211: do link->MLD address translation on RX

In some cases, e.g. with Qualcomm devices and management
frames, or in hwsim, frames may be reported from the driver
with link addresses, but for decryption and matching needs
we really want to have them with MLD addresses. Support the
translation on RX.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/rx.c

@@ -4724,6 +4724,9 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx,
 {
 	struct ieee80211_local *local = rx->local;
 	struct ieee80211_sub_if_data *sdata = rx->sdata;
+	struct ieee80211_hdr *hdr = (void *)skb->data;
+	struct link_sta_info *link_sta = NULL;
+	struct ieee80211_link_data *link;
 
 	rx->skb = skb;
 
@@ -4745,6 +4748,15 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx,
 	if (!ieee80211_accept_frame(rx))
 		return false;
 
+	if (unlikely(!is_multicast_ether_addr(hdr->addr1) &&
+		     rx->link_id >= 0 && rx->sta && rx->sta->sta.mlo)) {
+		link_sta = rcu_dereference(rx->sta->link[rx->link_id]);
+		link = rcu_dereference(rx->sdata->link[rx->link_id]);
+
+		if (WARN_ON_ONCE(!link_sta || !link))
+			return true;
+	}
+
 	if (!consume) {
 		skb = skb_copy(skb, GFP_ATOMIC);
 		if (!skb) {
@@ -4758,6 +4770,19 @@ static bool ieee80211_prepare_and_rx_handle(struct ieee80211_rx_data *rx,
 		rx->skb = skb;
 	}
 
+	if (unlikely(link_sta)) {
+		/* translate to MLD addresses */
+		if (ether_addr_equal(link->conf->addr, hdr->addr1))
+			ether_addr_copy(hdr->addr1, rx->sdata->vif.addr);
+		if (ether_addr_equal(link_sta->addr, hdr->addr2))
+			ether_addr_copy(hdr->addr2, rx->sta->addr);
+		if (ether_addr_equal(link_sta->addr, hdr->addr3))
+			ether_addr_copy(hdr->addr3, rx->sta->addr);
+		else if (ether_addr_equal(link->conf->addr, hdr->addr3))
+			ether_addr_copy(hdr->addr3, rx->sdata->vif.addr);
+		/* not needed for A4 since it can only carry the SA */
+	}
+
 	ieee80211_invoke_rx_handlers(rx);
 	return true;
 }