mac80211: receive and process S1G beacons

S1G beacons are 802.11 Extension Frames, so the fixed
header part differs from regular beacons.

Add a handler to process S1G beacons and abstract out the
fetching of BSSID and element start locations in the
beacon body handler.
Signed-off-by: Thomas Pedersen <thomas@adapt-ip.com>
Link: https://lore.kernel.org/r/20200922022818.15855-14-thomas@adapt-ip.com
[don't rename, small coding style cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

net/mac80211/ieee80211_i.h

@@ -1656,6 +1656,8 @@ int ieee80211_set_arp_filter(struct ieee80211_sub_if_data *sdata);
 void ieee80211_sta_work(struct ieee80211_sub_if_data *sdata);
 void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 				  struct sk_buff *skb);
+void ieee80211_sta_rx_queued_ext(struct ieee80211_sub_if_data *sdata,
+				 struct sk_buff *skb);
 void ieee80211_sta_reset_beacon_monitor(struct ieee80211_sub_if_data *sdata);
 void ieee80211_sta_reset_conn_monitor(struct ieee80211_sub_if_data *sdata);
 void ieee80211_mgd_stop(struct ieee80211_sub_if_data *sdata);
@@ -2301,6 +2303,8 @@ void ieee80211_tdls_handle_disconnect(struct ieee80211_sub_if_data *sdata,
 				      const u8 *peer, u16 reason);
 const char *ieee80211_get_reason_code_string(u16 reason_code);
 u16 ieee80211_encode_usf(int val);
+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+			enum nl80211_iftype type);
 
 extern const struct ethtool_ops ieee80211_ethtool_ops;
 

net/mac80211/iface.c

@@ -1433,6 +1433,11 @@ static void ieee80211_iface_work(struct work_struct *work)
 				WARN_ON(1);
 				break;
 			}
+		} else if (ieee80211_is_ext(mgmt->frame_control)) {
+			if (sdata->vif.type == NL80211_IFTYPE_STATION)
+				ieee80211_sta_rx_queued_ext(sdata, skb);
+			else
+				WARN_ON(1);
 		} else if (ieee80211_is_data_qos(mgmt->frame_control)) {
 			struct ieee80211_hdr *hdr = (void *)mgmt;
 			/*

net/mac80211/mlme.c

@@ -1602,6 +1602,9 @@ static u32 ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,
 	int new_ap_level;
 	__le16 capab = mgmt->u.probe_resp.capab_info;
 
+	if (ieee80211_is_s1g_beacon(mgmt->frame_control))
+		return 0;	/* TODO */
+
 	if (country_ie &&
 	    (capab & cpu_to_le16(WLAN_CAPABILITY_SPECTRUM_MGMT) ||
 	     capab & cpu_to_le16(WLAN_CAPABILITY_RADIO_MEASURE))) {
@@ -3896,11 +3899,12 @@ static bool ieee80211_rx_our_beacon(const u8 *tx_bssid,
 }
 
 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
-				     struct ieee80211_mgmt *mgmt, size_t len,
+				     struct ieee80211_hdr *hdr, size_t len,
 				     struct ieee80211_rx_status *rx_status)
 {
 	struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
 	struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
+	struct ieee80211_mgmt *mgmt = (void *) hdr;
 	size_t baselen;
 	struct ieee802_11_elems elems;
 	struct ieee80211_local *local = sdata->local;
@@ -3910,14 +3914,24 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	u32 changed = 0;
 	bool erp_valid;
 	u8 erp_value = 0;
-	u32 ncrc;
-	u8 *bssid;
+	u32 ncrc = 0;
+	u8 *bssid, *variable = mgmt->u.beacon.variable;
 	u8 deauth_buf[IEEE80211_DEAUTH_FRAME_LEN];
 
 	sdata_assert_lock(sdata);
 
 	/* Process beacon from the current BSS */
-	baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
+	bssid = ieee80211_get_bssid(hdr, len, sdata->vif.type);
+	if (ieee80211_is_s1g_beacon(mgmt->frame_control)) {
+		struct ieee80211_ext *ext = (void *) mgmt;
+
+		if (ieee80211_is_s1g_short_beacon(ext->frame_control))
+			variable = ext->u.s1g_short_beacon.variable;
+		else
+			variable = ext->u.s1g_beacon.variable;
+	}
+
+	baselen = (u8 *) variable - (u8 *) mgmt;
 	if (baselen > len)
 		return;
 
@@ -3937,10 +3951,10 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	rcu_read_unlock();
 
 	if (ifmgd->assoc_data && ifmgd->assoc_data->need_beacon &&
-	    ieee80211_rx_our_beacon(mgmt->bssid, ifmgd->assoc_data->bss)) {
-		ieee802_11_parse_elems(mgmt->u.beacon.variable,
+	    ieee80211_rx_our_beacon(bssid, ifmgd->assoc_data->bss)) {
+		ieee802_11_parse_elems(variable,
 				       len - baselen, false, &elems,
-				       mgmt->bssid,
+				       bssid,
 				       ifmgd->assoc_data->bss->bssid);
 
 		ieee80211_rx_bss_info(sdata, mgmt, len, rx_status);
@@ -3973,7 +3987,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	}
 
 	if (!ifmgd->associated ||
-	    !ieee80211_rx_our_beacon(mgmt->bssid,  ifmgd->associated))
+	    !ieee80211_rx_our_beacon(bssid,  ifmgd->associated))
 		return;
 	bssid = ifmgd->associated->bssid;
 
@@ -3993,8 +4007,14 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	 */
 	ieee80211_sta_reset_beacon_monitor(sdata);
 
-	ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
-	ncrc = ieee802_11_parse_elems_crc(mgmt->u.beacon.variable,
+	/* TODO: CRC urrently not calculated on S1G Beacon Compatibility
+	 * element (which carries the beacon interval). Don't forget to add a
+	 * bit to care_about_ies[] above if mac80211 is interested in a
+	 * changing S1G element.
+	 */
+	if (!ieee80211_is_s1g_beacon(hdr->frame_control))
+		ncrc = crc32_be(0, (void *)&mgmt->u.beacon.beacon_int, 4);
+	ncrc = ieee802_11_parse_elems_crc(variable,
 					  len - baselen, false, &elems,
 					  care_about_ies, ncrc,
 					  mgmt->bssid, bssid);
@@ -4028,7 +4048,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 		struct ieee80211_p2p_noa_attr noa = {};
 		int ret;
 
-		ret = cfg80211_get_p2p_attr(mgmt->u.beacon.variable,
+		ret = cfg80211_get_p2p_attr(variable,
 					    len - baselen,
 					    IEEE80211_P2P_ATTR_ABSENCE_NOTICE,
 					    (u8 *) &noa, sizeof(noa));
@@ -4064,7 +4084,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	 * the driver will use them. The synchronized view is currently
 	 * guaranteed only in certain callbacks.
 	 */
-	if (ieee80211_hw_check(&local->hw, TIMING_BEACON_ONLY)) {
+	if (ieee80211_hw_check(&local->hw, TIMING_BEACON_ONLY) &&
+	    !ieee80211_is_s1g_beacon(hdr->frame_control)) {
 		sdata->vif.bss_conf.sync_tsf =
 			le64_to_cpu(mgmt->u.beacon.timestamp);
 		sdata->vif.bss_conf.sync_device_ts =
@@ -4072,7 +4093,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 		sdata->vif.bss_conf.sync_dtim_count = elems.dtim_count;
 	}
 
-	if (ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid)
+	if ((ncrc == ifmgd->beacon_crc && ifmgd->beacon_crc_valid) ||
+	    ieee80211_is_s1g_short_beacon(mgmt->frame_control))
 		return;
 	ifmgd->beacon_crc = ncrc;
 	ifmgd->beacon_crc_valid = true;
@@ -4113,9 +4135,11 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	} else {
 		erp_valid = false;
 	}
-	changed |= ieee80211_handle_bss_capability(sdata,
-			le16_to_cpu(mgmt->u.beacon.capab_info),
-			erp_valid, erp_value);
+
+	if (!ieee80211_is_s1g_beacon(hdr->frame_control))
+		changed |= ieee80211_handle_bss_capability(sdata,
+				le16_to_cpu(mgmt->u.beacon.capab_info),
+				erp_valid, erp_value);
 
 	mutex_lock(&local->sta_mtx);
 	sta = sta_info_get(sdata, bssid);
@@ -4153,6 +4177,26 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 	ieee80211_bss_info_change_notify(sdata, changed);
 }
 
+void ieee80211_sta_rx_queued_ext(struct ieee80211_sub_if_data *sdata,
+				 struct sk_buff *skb)
+{
+	struct ieee80211_rx_status *rx_status;
+	struct ieee80211_hdr *hdr;
+	u16 fc;
+
+	rx_status = (struct ieee80211_rx_status *) skb->cb;
+	hdr = (struct ieee80211_hdr *) skb->data;
+	fc = le16_to_cpu(hdr->frame_control);
+
+	sdata_lock(sdata);
+	switch (fc & IEEE80211_FCTL_STYPE) {
+	case IEEE80211_STYPE_S1G_BEACON:
+		ieee80211_rx_mgmt_beacon(sdata, hdr, skb->len, rx_status);
+		break;
+	}
+	sdata_unlock(sdata);
+}
+
 void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 				  struct sk_buff *skb)
 {
@@ -4170,7 +4214,8 @@ void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 
 	switch (fc & IEEE80211_FCTL_STYPE) {
 	case IEEE80211_STYPE_BEACON:
-		ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len, rx_status);
+		ieee80211_rx_mgmt_beacon(sdata, (void *)mgmt,
+					 skb->len, rx_status);
 		break;
 	case IEEE80211_STYPE_PROBE_RESP:
 		ieee80211_rx_mgmt_probe_resp(sdata, skb);

net/mac80211/rx.c

@@ -42,51 +42,6 @@ static inline void ieee80211_rx_stats(struct net_device *dev, u32 len)
 	u64_stats_update_end(&tstats->syncp);
 }
 
-static u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
-			       enum nl80211_iftype type)
-{
-	__le16 fc = hdr->frame_control;
-
-	if (ieee80211_is_data(fc)) {
-		if (len < 24) /* drop incorrect hdr len (data) */
-			return NULL;
-
-		if (ieee80211_has_a4(fc))
-			return NULL;
-		if (ieee80211_has_tods(fc))
-			return hdr->addr1;
-		if (ieee80211_has_fromds(fc))
-			return hdr->addr2;
-
-		return hdr->addr3;
-	}
-
-	if (ieee80211_is_mgmt(fc)) {
-		if (len < 24) /* drop incorrect hdr len (mgmt) */
-			return NULL;
-		return hdr->addr3;
-	}
-
-	if (ieee80211_is_ctl(fc)) {
-		if (ieee80211_is_pspoll(fc))
-			return hdr->addr1;
-
-		if (ieee80211_is_back_req(fc)) {
-			switch (type) {
-			case NL80211_IFTYPE_STATION:
-				return hdr->addr2;
-			case NL80211_IFTYPE_AP:
-			case NL80211_IFTYPE_AP_VLAN:
-				return hdr->addr1;
-			default:
-				break; /* fall through to the return */
-			}
-		}
-	}
-
-	return NULL;
-}
-
 /*
  * monitor mode reception
  *
@@ -1802,7 +1757,8 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 		}
 	} else if (rx->sdata->vif.type == NL80211_IFTYPE_OCB) {
 		sta->rx_stats.last_rx = jiffies;
-	} else if (!is_multicast_ether_addr(hdr->addr1)) {
+	} else if (!ieee80211_is_s1g_beacon(hdr->frame_control) &&
+		   is_multicast_ether_addr(hdr->addr1)) {
 		/*
 		 * Mesh beacons will update last_rx when if they are found to
 		 * match the current local configuration when processed.
@@ -1837,6 +1793,9 @@ ieee80211_rx_h_sta_process(struct ieee80211_rx_data *rx)
 		}
 	}
 
+	if (ieee80211_is_s1g_beacon(hdr->frame_control))
+		return RX_CONTINUE;
+
 	/*
 	 * Change STA power saving mode only at the end of a frame
 	 * exchange sequence, and only for a data or management
@@ -1947,6 +1906,9 @@ ieee80211_rx_h_decrypt(struct ieee80211_rx_data *rx)
 	__le16 fc;
 	const struct ieee80211_cipher_scheme *cs = NULL;
 
+	if (ieee80211_is_ext(hdr->frame_control))
+		return RX_CONTINUE;
+
 	/*
 	 * Key selection 101
 	 *
@@ -2255,7 +2217,7 @@ ieee80211_rx_h_defragment(struct ieee80211_rx_data *rx)
 	hdr = (struct ieee80211_hdr *)rx->skb->data;
 	fc = hdr->frame_control;
 
-	if (ieee80211_is_ctl(fc))
+	if (ieee80211_is_ctl(fc) || ieee80211_is_ext(fc))
 		return RX_CONTINUE;
 
 	sc = le16_to_cpu(hdr->seq_ctrl);
@@ -3129,6 +3091,9 @@ ieee80211_rx_h_mgmt_check(struct ieee80211_rx_data *rx)
 	struct ieee80211_mgmt *mgmt = (struct ieee80211_mgmt *) rx->skb->data;
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(rx->skb);
 
+	if (ieee80211_is_s1g_beacon(mgmt->frame_control))
+		return RX_CONTINUE;
+
 	/*
 	 * From here on, look only at management frames.
 	 * Data and control frames are already handled,
@@ -3595,6 +3560,27 @@ ieee80211_rx_h_action_return(struct ieee80211_rx_data *rx)
 	return RX_QUEUED;
 }
 
+static ieee80211_rx_result debug_noinline
+ieee80211_rx_h_ext(struct ieee80211_rx_data *rx)
+{
+	struct ieee80211_sub_if_data *sdata = rx->sdata;
+	struct ieee80211_hdr *hdr = (void *)rx->skb->data;
+
+	if (!ieee80211_is_ext(hdr->frame_control))
+		return RX_CONTINUE;
+
+	if (sdata->vif.type != NL80211_IFTYPE_STATION)
+		return RX_DROP_MONITOR;
+
+	/* for now only beacons are ext, so queue them */
+	skb_queue_tail(&sdata->skb_queue, rx->skb);
+	ieee80211_queue_work(&rx->local->hw, &sdata->work);
+	if (rx->sta)
+		rx->sta->rx_stats.packets++;
+
+	return RX_QUEUED;
+}
+
 static ieee80211_rx_result debug_noinline
 ieee80211_rx_h_mgmt(struct ieee80211_rx_data *rx)
 {
@@ -3814,6 +3800,7 @@ static void ieee80211_rx_handlers(struct ieee80211_rx_data *rx,
 		CALL_RXH(ieee80211_rx_h_userspace_mgmt);
 		CALL_RXH(ieee80211_rx_h_action_post_userspace);
 		CALL_RXH(ieee80211_rx_h_action_return);
+		CALL_RXH(ieee80211_rx_h_ext);
 		CALL_RXH(ieee80211_rx_h_mgmt);
 
  rxh_next:
@@ -3980,7 +3967,8 @@ static bool ieee80211_accept_frame(struct ieee80211_rx_data *rx)
 	struct ieee80211_hdr *hdr = (void *)skb->data;
 	struct ieee80211_rx_status *status = IEEE80211_SKB_RXCB(skb);
 	u8 *bssid = ieee80211_get_bssid(hdr, skb->len, sdata->vif.type);
-	bool multicast = is_multicast_ether_addr(hdr->addr1);
+	bool multicast = is_multicast_ether_addr(hdr->addr1) ||
+			 ieee80211_is_s1g_beacon(hdr->frame_control);
 
 	switch (sdata->vif.type) {
 	case NL80211_IFTYPE_STATION:

net/mac80211/util.c

@@ -45,6 +45,58 @@ struct ieee80211_hw *wiphy_to_ieee80211_hw(struct wiphy *wiphy)
 }
 EXPORT_SYMBOL(wiphy_to_ieee80211_hw);
 
+u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
+			enum nl80211_iftype type)
+{
+	__le16 fc = hdr->frame_control;
+
+	if (ieee80211_is_data(fc)) {
+		if (len < 24) /* drop incorrect hdr len (data) */
+			return NULL;
+
+		if (ieee80211_has_a4(fc))
+			return NULL;
+		if (ieee80211_has_tods(fc))
+			return hdr->addr1;
+		if (ieee80211_has_fromds(fc))
+			return hdr->addr2;
+
+		return hdr->addr3;
+	}
+
+	if (ieee80211_is_s1g_beacon(fc)) {
+		struct ieee80211_ext *ext = (void *) hdr;
+
+		return ext->u.s1g_beacon.sa;
+	}
+
+	if (ieee80211_is_mgmt(fc)) {
+		if (len < 24) /* drop incorrect hdr len (mgmt) */
+			return NULL;
+		return hdr->addr3;
+	}
+
+	if (ieee80211_is_ctl(fc)) {
+		if (ieee80211_is_pspoll(fc))
+			return hdr->addr1;
+
+		if (ieee80211_is_back_req(fc)) {
+			switch (type) {
+			case NL80211_IFTYPE_STATION:
+				return hdr->addr2;
+			case NL80211_IFTYPE_AP:
+			case NL80211_IFTYPE_AP_VLAN:
+				return hdr->addr1;
+			default:
+				break; /* fall through to the return */
+			}
+		}
+	}
+
+	return NULL;
+}
+EXPORT_SYMBOL(ieee80211_get_bssid);
+
 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 {
 	struct sk_buff *skb;