mac80211: prepare sta handling for MLO support

Currently in mac80211 each STA object is represented
using sta_info datastructure with the associated
STA specific information and drivers access ieee80211_sta
part of it.

With MLO (Multi Link Operation) support being added
in 802.11be standard, though the association is logically
with a single Multi Link capable STA, at the physical level
communication can happen via different advertised
links (uniquely identified by Channel, operating class,
BSSID) and hence the need to handle multiple link
STA parameters within a composite sta_info object
called the MLD STA. The different link STA part of
MLD STA are identified using the link address which can
be same or different as the MLD STA address and unique
link id based on the link vif.

To support extension of such a model, the sta_info
datastructure is modified to hold multiple link STA
objects with link specific params currently within
sta_info moved to this new structure. Similarly this is
done for ieee80211_sta as well which will be accessed
within mac80211 as well as by drivers, hence trivial
driver changes are expected to support this.

For current non MLO supported drivers, only one link STA
is present and link information is accessed via 'deflink'
member.

For MLO drivers, we still need to define the APIs etc. to
get the correct link ID and access the correct part of
the station info.

Currently in mac80211, all link STA info are accessed directly
via deflink. These will be updated to access via link pointers
indexed by link id with MLO support patches, with link id
being 0 for non MLO supported cases.

Except for couple of macro related changes, below spatch takes
care of updating mac80211 and driver code to access to the
link STA info via deflink.

  @ieee80211_sta@
  struct ieee80211_sta *s;
  struct sta_info *si;
  identifier var = {supp_rates, ht_cap, vht_cap, he_cap, he_6ghz_capa, eht_cap, rx_nss, bandwidth, txpwr};
  @@

  (
    s->
  -    var
  +    deflink.var
  |
   si->sta.
  -    var
  +    deflink.var
  )

  @sta_info@
  struct sta_info *si;
  identifier var = {gtk, pcpu_rx_stats, rx_stats, rx_stats_avg, status_stats, tx_stats, cur_max_bandwidth};
  @@

  (
    si->
  -    var
  +    deflink.var
  )

Signed-off-by: Sriram R <quic_srirrama@quicinc.com>
Link: https://lore.kernel.org/r/1649086883-13246-1-git-send-email-quic_srirrama@quicinc.com
[remove MLO-drivers notes from commit message, not clear yet; run spatch]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 58 insertions, 22 deletions

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0943b2626f4d..75880fc70700 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2056,6 +2056,45 @@ struct ieee80211_sta_txpwr {
 	enum nl80211_tx_power_setting type;
 };
 
+#define MAX_STA_LINKS			15
+
+/**
+ * struct ieee80211_link_sta - station Link specific info
+ * All link specific info for a STA link for a non MLD STA(single)
+ * or a MLD STA(multiple entries) are stored here.
+ *
+ * @addr: MAC address of the Link STA. For non-MLO STA this is same as the addr
+ *	in ieee80211_sta. For MLO Link STA this addr can be same or different
+ *	from addr in ieee80211_sta (representing MLD STA addr)
+ * @supp_rates: Bitmap of supported rates
+ * @ht_cap: HT capabilities of this STA; restricted to our own capabilities
+ * @vht_cap: VHT capabilities of this STA; restricted to our own capabilities
+ * @he_cap: HE capabilities of this STA
+ * @he_6ghz_capa: on 6 GHz, holds the HE 6 GHz band capabilities
+ * @eht_cap: EHT capabilities of this STA
+ * @bandwidth: current bandwidth the station can receive with
+ * @rx_nss: in HT/VHT, the maximum number of spatial streams the
+ *	station can receive at the moment, changed by operating mode
+ *	notifications and capabilities. The value is only valid after
+ *	the station moves to associated state.
+ * @txpwr: the station tx power configuration
+ *
+ */
+struct ieee80211_link_sta {
+	u8 addr[ETH_ALEN];
+
+	u32 supp_rates[NUM_NL80211_BANDS];
+	struct ieee80211_sta_ht_cap ht_cap;
+	struct ieee80211_sta_vht_cap vht_cap;
+	struct ieee80211_sta_he_cap he_cap;
+	struct ieee80211_he_6ghz_capa he_6ghz_capa;
+	struct ieee80211_sta_eht_cap eht_cap;
+
+	u8 rx_nss;
+	enum ieee80211_sta_rx_bandwidth bandwidth;
+	struct ieee80211_sta_txpwr txpwr;
+};
+
 /**
  * struct ieee80211_sta - station table entry
  *
@@ -2065,15 +2104,11 @@ struct ieee80211_sta_txpwr {
  * either be protected by rcu_read_lock() explicitly or implicitly,
  * or you must take good care to not use such a pointer after a
  * call to your sta_remove callback that removed it.
+ * This also represents the MLD STA in case of MLO association
+ * and holds pointers to various link STA's
  *
  * @addr: MAC address
  * @aid: AID we assigned to the station if we're an AP
- * @supp_rates: Bitmap of supported rates (per band)
- * @ht_cap: HT capabilities of this STA; restricted to our own capabilities
- * @vht_cap: VHT capabilities of this STA; restricted to our own capabilities
- * @he_cap: HE capabilities of this STA
- * @he_6ghz_capa: on 6 GHz, holds the HE 6 GHz band capabilities
- * @eht_cap: EHT capabilities of this STA
  * @max_rx_aggregation_subframes: maximal amount of frames in a single AMPDU
  *	that this station is allowed to transmit to us.
  *	Can be modified by driver.
@@ -2085,11 +2120,6 @@ struct ieee80211_sta_txpwr {
  *	if wme is supported. The bits order is like in
  *	IEEE80211_WMM_IE_STA_QOSINFO_AC_*.
  * @max_sp: max Service Period. Only valid if wme is supported.
- * @bandwidth: current bandwidth the station can receive with
- * @rx_nss: in HT/VHT, the maximum number of spatial streams the
- *	station can receive at the moment, changed by operating mode
- *	notifications and capabilities. The value is only valid after
- *	the station moves to associated state.
  * @smps_mode: current SMPS mode (off, static or dynamic)
  * @rates: rate control selection table
  * @tdls: indicates whether the STA is a TDLS peer
@@ -2102,25 +2132,28 @@ struct ieee80211_sta_txpwr {
  * @support_p2p_ps: indicates whether the STA supports P2P PS mechanism or not.
  * @max_rc_amsdu_len: Maximum A-MSDU size in bytes recommended by rate control.
  * @max_tid_amsdu_len: Maximum A-MSDU size in bytes for this TID
- * @txpwr: the station tx power configuration
  * @txq: per-TID data TX queues (if driver uses the TXQ abstraction); note that
  *	the last entry (%IEEE80211_NUM_TIDS) is used for non-data frames
+ * @multi_link_sta: Identifies if this sta is a MLD STA
+ * @deflink: This holds the default link STA information, for non MLO STA all link
+ *	specific STA information is accessed through @deflink or through
+ *	link[0] which points to address of @deflink. For MLO Link STA
+ *	the first added link STA will point to deflink.
+ * @link: reference to Link Sta entries. For Non MLO STA, except 1st link,
+ *	i.e link[0] all links would be assigned to NULL by default and
+ *	would access link information via @deflink or link[0]. For MLO
+ *	STA, first link STA being added will point its link pointer to
+ *	@deflink address and remaining would be allocated and the address
+ *	would be assigned to link[link_id] where link_id is the id assigned
+ *	by the AP.
  */
 struct ieee80211_sta {
-	u32 supp_rates[NUM_NL80211_BANDS];
 	u8 addr[ETH_ALEN];
 	u16 aid;
-	struct ieee80211_sta_ht_cap ht_cap;
-	struct ieee80211_sta_vht_cap vht_cap;
-	struct ieee80211_sta_he_cap he_cap;
-	struct ieee80211_he_6ghz_capa he_6ghz_capa;
-	struct ieee80211_sta_eht_cap eht_cap;
 	u16 max_rx_aggregation_subframes;
 	bool wme;
 	u8 uapsd_queues;
 	u8 max_sp;
-	u8 rx_nss;
-	enum ieee80211_sta_rx_bandwidth bandwidth;
 	enum ieee80211_smps_mode smps_mode;
 	struct ieee80211_sta_rates __rcu *rates;
 	bool tdls;
@@ -2147,10 +2180,13 @@ struct ieee80211_sta {
 	bool support_p2p_ps;
 	u16 max_rc_amsdu_len;
 	u16 max_tid_amsdu_len[IEEE80211_NUM_TIDS];
-	struct ieee80211_sta_txpwr txpwr;
 
 	struct ieee80211_txq *txq[IEEE80211_NUM_TIDS + 1];
 
+	bool multi_link_sta;
+	struct ieee80211_link_sta deflink;
+	struct ieee80211_link_sta *link[MAX_STA_LINKS];
+
 	/* must be last */
 	u8 drv_priv[] __aligned(sizeof(void *));
 };
@@ -6371,7 +6407,7 @@ static inline int rate_supported(struct ieee80211_sta *sta,
 				 enum nl80211_band band,
 				 int index)
 {
-	return (sta == NULL || sta->supp_rates[band] & BIT(index));
+	return (sta == NULL || sta->deflink.supp_rates[band] & BIT(index));
 }
 
 static inline s8