2019-06-29 19:56:37

by Alexander Wetzel

[permalink] [raw]
Subject: [PATCH 3/4] mac80211: AMPDU handling for rekeys with Extended Key ID

Extended Key ID allows A-MPDU sessions while rekeying as long as each
A-MPDU aggregates only MPDUs with one keyid together.

Drivers able to segregate MPDUs accordingly can tell mac80211 to not
stop A-MPDU sessions when rekeying by setting the new flag
IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT.

Signed-off-by: Alexander Wetzel <[email protected]>
---
include/net/mac80211.h | 5 +++++
net/mac80211/debugfs.c | 1 +
net/mac80211/key.c | 14 ++++++++------
3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 544dad54b11f..1d6bb67ecb47 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2268,6 +2268,10 @@ struct ieee80211_txq {
* @IEEE80211_HW_SUPPORTS_ONLY_HE_MULTI_BSSID: Hardware supports multi BSSID
* only for HE APs. Applies if @IEEE80211_HW_SUPPORTS_MULTI_BSSID is set.
*
+ * @IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT: The card and driver is only
+ * aggregating MPDUs with the same keyid, allowing mac80211 to keep Tx
+ * A-MPDU sessions active while rekeying with Extended Key ID.
+ *
* @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
*/
enum ieee80211_hw_flags {
@@ -2319,6 +2323,7 @@ enum ieee80211_hw_flags {
IEEE80211_HW_TX_STATUS_NO_AMPDU_LEN,
IEEE80211_HW_SUPPORTS_MULTI_BSSID,
IEEE80211_HW_SUPPORTS_ONLY_HE_MULTI_BSSID,
+ IEEE80211_HW_AMPDU_KEYBORDER_SUPPORT,

/* keep last, obviously */
NUM_IEEE80211_HW_FLAGS
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index 47435f57e086..568b3b276931 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -271,6 +271,7 @@ static const char *hw_flag_names[] = {
FLAG(TX_STATUS_NO_AMPDU_LEN),
FLAG(SUPPORTS_MULTI_BSSID),
FLAG(SUPPORTS_ONLY_HE_MULTI_BSSID),
+ FLAG(AMPDU_KEYBORDER_SUPPORT),
#undef FLAG
};

diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 92c3affb0eb0..7dfee848abac 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -270,7 +270,8 @@ int ieee80211_set_tx_key(struct ieee80211_key *key)

sta->ptk_idx = key->conf.keyidx;

- clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
+ if (!ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT))
+ clear_sta_flag(sta, WLAN_STA_BLOCK_BA);
ieee80211_check_fast_xmit(sta);

return 0;
@@ -288,15 +289,16 @@ static void ieee80211_pairwise_rekey(struct ieee80211_key *old,
if (new->conf.flags & IEEE80211_KEY_FLAG_NO_AUTO_TX) {
/* Extended Key ID key install, initial one or rekey */

- if (sta->ptk_idx != INVALID_PTK_KEYIDX) {
+ if (sta->ptk_idx != INVALID_PTK_KEYIDX &&
+ !ieee80211_hw_check(&local->hw, AMPDU_KEYBORDER_SUPPORT)) {
/* Aggregation Sessions with Extended Key ID must not
* mix MPDUs with different keyIDs within one A-MPDU.
* Tear down running Tx aggregation sessions and block
* new Rx/Tx aggregation requests during rekey to
- * ensure there are no A-MPDUs for the driver to
- * aggregate. (Blocking Tx only would be sufficient but
- * WLAN_STA_BLOCK_BA gets the job done for the few ms
- * we need it.)
+ * ensure there are no A-MPDUs when the driver is not
+ * supporting A-MPDU key borders. (Blocking Tx only
+ * would be sufficient but WLAN_STA_BLOCK_BA gets the
+ * job done for the few ms we need it.)
*/
set_sta_flag(sta, WLAN_STA_BLOCK_BA);
mutex_lock(&sta->ampdu_mlme.mtx);
--
2.22.0