To detect incoming 4-addr stations, hostapd needs to receive a 4-addr
data frame from the remote station, so that it can create the AP VLAN
for it. With this patch, the mlme code emits a 4-addr nullfunc frame
immediately after assoc. On the AP side it also drops 4-addr nullfunc
frames to the cooked monitor mode interface, if the interface hasn't
been fully set up to receive 4-addr data frames yet.
Signed-off-by: Felix Fietkau <nbd@xxxxxxxxxxx>
---
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -312,6 +312,38 @@ void ieee80211_send_nullfunc(struct ieee
ieee80211_tx_skb(sdata, skb);
}
+static void ieee80211_send_4addr_nullfunc(struct ieee80211_local *local,
+ struct ieee80211_sub_if_data *sdata)
+{
+ struct sk_buff *skb;
+ struct ieee80211_hdr *nullfunc;
+ __le16 fc;
+
+ if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_STATION))
+ return;
+
+ skb = dev_alloc_skb(local->hw.extra_tx_headroom + 30);
+ if (!skb) {
+ printk(KERN_DEBUG "%s: failed to allocate buffer for 4addr "
+ "nullfunc frame\n", sdata->name);
+ return;
+ }
+ skb_reserve(skb, local->hw.extra_tx_headroom);
+
+ nullfunc = (struct ieee80211_hdr *) skb_put(skb, 30);
+ memset(nullfunc, 0, 30);
+ fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
+ IEEE80211_FCTL_FROMDS | IEEE80211_FCTL_TODS);
+ nullfunc->frame_control = fc;
+ memcpy(nullfunc->addr1, sdata->u.mgd.bssid, ETH_ALEN);
+ memcpy(nullfunc->addr2, sdata->vif.addr, ETH_ALEN);
+ memcpy(nullfunc->addr3, sdata->u.mgd.bssid, ETH_ALEN);
+ memcpy(nullfunc->addr4, sdata->vif.addr, ETH_ALEN);
+
+ IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+ ieee80211_tx_skb(sdata, skb);
+}
+
/* spectrum management related things */
static void ieee80211_chswitch_work(struct work_struct *work)
{
@@ -1120,6 +1152,13 @@ static bool ieee80211_assoc_success(stru
ieee80211_set_associated(sdata, cbss, changed);
/*
+ * If we're using 4-addr mode, let the AP know that we're
+ * doing so, so that it can create the STA VLAN on its side
+ */
+ if (ifmgd->use_4addr)
+ ieee80211_send_4addr_nullfunc(local, sdata);
+
+ /*
* Start timer to probe the connection to the AP now.
* Also start the timer that will detect beacon loss.
*/
--- a/net/mac80211/rx.c
+++ b/net/mac80211/rx.c
@@ -1111,6 +1111,18 @@ ieee80211_rx_h_sta_process(struct ieee80
if (ieee80211_is_nullfunc(hdr->frame_control) ||
ieee80211_is_qos_nullfunc(hdr->frame_control)) {
I802_DEBUG_INC(rx->local->rx_handlers_drop_nullfunc);
+
+ /*
+ * If we receive a 4-addr nullfunc frame from a STA
+ * that was not moved to a 4-addr STA vlan yet, drop
+ * the frame to the monitor interface, to make sure
+ * that hostapd sees it
+ */
+ if (ieee80211_has_a4(hdr->frame_control) &&
+ (rx->sdata->vif.type == NL80211_IFTYPE_AP ||
+ (rx->sdata->vif.type == NL80211_IFTYPE_AP_VLAN &&
+ !rx->sdata->u.vlan.sta)))
+ return RX_DROP_MONITOR;
/*
* Update counter and free packet here to avoid
* counting this as a dropped packed.
--
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