Some APs request a BA agreement and continue to send QOS packets
for the same tid (with normal ack policy). Currently, these packets
make it to the higher layers without going through BA reordering or the
BA buffer. This results in reduced performance later on as the sequence
numbers are expected by BA reordering.
To fix this, we should use BA agreement immediately after it is
requested by the AP. This causes the sequence number counter in
the BA agreement to advance for the normal qos packets and the gap
wait later on is avoided.
ok?
Index: ieee80211_input.c
===================================================================
RCS file: /cvs/src/sys/net80211/ieee80211_input.c,v
retrieving revision 1.221
diff -u -p -r1.221 ieee80211_input.c
--- ieee80211_input.c 28 Aug 2020 12:01:48 -0000 1.221
+++ ieee80211_input.c 7 Dec 2020 11:57:19 -0000
@@ -358,6 +358,18 @@ ieee80211_inputm(struct ifnet *ifp, stru
/* go through A-MPDU reordering */
ieee80211_input_ba(ic, m, ni, tid, rxi, ml);
return; /* don't free m! */
+ } else if (ba_state == IEEE80211_BA_REQUESTED &&
+ (qos & IEEE80211_QOS_ACK_POLICY_MASK) ==
+ IEEE80211_QOS_ACK_POLICY_NORMAL) {
+ /*
+ * Apparently, qos frames for a tid where a
+ * block ack agreement was requested but not
+ * yet confirmed by us should still contribute
+ * to the sequence number for this tid.
+ * XXX Add quote from the standard...
+ */
+ ieee80211_input_ba(ic, m, ni, tid, rxi, ml);
+ return; /* don't free m! */
}
}
@@ -2698,6 +2710,9 @@ ieee80211_recv_addba_req(struct ieee8021
ssn = LE_READ_2(&frm[7]) >> 4;
ba = &ni->ni_rx_ba[tid];
+ /* The driver is still processing an ADDBA request for this tid. */
+ if (ba->ba_state == IEEE80211_BA_REQUESTED)
+ return;
/* check if we already have a Block Ack agreement for this RA/TID */
if (ba->ba_state == IEEE80211_BA_AGREED) {
/* XXX should we update the timeout value? */
@@ -2737,7 +2752,7 @@ ieee80211_recv_addba_req(struct ieee8021
goto refuse;
/* setup Block Ack agreement */
- ba->ba_state = IEEE80211_BA_INIT;
+ ba->ba_state = IEEE80211_BA_REQUESTED;
ba->ba_timeout_val = timeout * IEEE80211_DUR_TU;
ba->ba_ni = ni;
ba->ba_token = token;
@@ -2811,11 +2826,20 @@ void
ieee80211_addba_req_refuse(struct ieee80211com *ic, struct ieee80211_node *ni,
uint8_t tid)
{
+#ifdef IEEE80211_DEBUG
+ struct ifnet *ifp = &ic->ic_if;
+#endif
struct ieee80211_rx_ba *ba = &ni->ni_rx_ba[tid];
+ if (ba->ba_state != IEEE80211_BA_REQUESTED) {
+ DPRINTF(("%s: Invalid ba_state=%d\n", ifp->if_xname,
+ ba->ba_state));
+ }
+
free(ba->ba_buf, M_DEVBUF,
IEEE80211_BA_MAX_WINSZ * sizeof(*ba->ba_buf));
ba->ba_buf = NULL;
+ ba->ba_state = IEEE80211_BA_INIT;
/* MLME-ADDBA.response */
IEEE80211_SEND_ACTION(ic, ni, IEEE80211_CATEG_BA,
