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>

1 files changed, 62 insertions, 17 deletions

diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 70b6f5ee4757..fbe64a72eaff 100644
--- a/net/mac80211/mlme.c
+++ b/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);