mac80211: A-MPDU Rx adding basic functionality

This patch adds the basic needed abilities and functions for A-MPDU Rx session
changed functions:
 - ieee80211_sta_process_addba_request - Rx A-MPDU initialization enabled
 - ieee80211_stop - stops all A-MPDU Rx in case interface goes down
added functions:
 - ieee80211_send_delba - used for sending out Del BA in A-MPDU sessions
 - ieee80211_sta_stop_rx_BA_session - stopping Rx A-MPDU session
 - sta_rx_agg_session_timer_expired - stops A-MPDU Rx use if load is too
low

Signed-off-by: Ron Rindjunsky <ron.rindjunsky@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 232 insertions, 11 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 3e641590d0c8..4d5a4c9dcba7 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -472,6 +472,13 @@ enum ieee80211_back_actioncode {
         WLAN_ACTION_DELBA = 2,
 };
 
+/* BACK (block-ack) parties */
+enum ieee80211_back_parties {
+        WLAN_BACK_RECIPIENT = 0,
+        WLAN_BACK_INITIATOR = 1,
+        WLAN_BACK_TIMER = 2,
+};
+
 /* A-MSDU 802.11n */
 #define IEEE80211_QOS_CONTROL_A_MSDU_PRESENT 0x0080
 
diff --git a/net/mac80211/ieee80211.c b/net/mac80211/ieee80211.c
index 9c14e3d303c5..2011c726f2b1 100644
--- a/net/mac80211/ieee80211.c
+++ b/net/mac80211/ieee80211.c
@@ -292,9 +292,18 @@ static int ieee80211_stop(struct net_device *dev)
         struct ieee80211_sub_if_data *sdata;
         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
         struct ieee80211_if_init_conf conf;
+        struct sta_info *sta;
+        int i;
 
         sdata = IEEE80211_DEV_TO_SUB_IF(dev);
 
+        list_for_each_entry(sta, &local->sta_list, list) {
+                for (i = 0; i <  STA_TID_NUM; i++)
+                        ieee80211_sta_stop_rx_ba_session(sta->dev, sta->addr,
+                                                i, WLAN_BACK_RECIPIENT,
+                                                WLAN_REASON_QSTA_LEAVE_QBSS);
+        }
+
         netif_stop_queue(dev);
 
         /*
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index baf53c047127..740d69d5bbd3 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -767,6 +767,9 @@ int ieee80211_ht_cap_ie_to_ht_info(struct ieee80211_ht_cap *ht_cap_ie,
 int ieee80211_ht_addt_info_ie_to_ht_bss_info(
                         struct ieee80211_ht_addt_info *ht_add_info_ie,
                         struct ieee80211_ht_bss_info *bss_info);
+void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *da,
+                                u16 tid, u16 initiator, u16 reason);
+void sta_rx_agg_session_timer_expired(unsigned long data);
 /* ieee80211_iface.c */
 int ieee80211_if_add(struct net_device *dev, const char *name,
                      struct net_device **new_dev, int type);
diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c
index 5b8f484c1673..d5a7683fab3a 100644
--- a/net/mac80211/ieee80211_sta.c
+++ b/net/mac80211/ieee80211_sta.c
@@ -64,6 +64,11 @@
 #define IEEE80211_ADDBA_PARAM_TID_MASK 0x003C
 #define IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK 0xFFA0
 
+/* next values represent the buffer size for A-MPDU frame.
+ * According to IEEE802.11n spec size varies from 8K to 64K (in powers of 2) */
+#define IEEE80211_MIN_AMPDU_BUF 0x8
+#define IEEE80211_MAX_AMPDU_BUF 0x40
+
 static void ieee80211_send_probe_req(struct net_device *dev, u8 *dst,
                                      u8 *ssid, size_t ssid_len);
 static struct ieee80211_sta_bss *
@@ -1005,7 +1010,8 @@ static void ieee80211_send_addba_resp(struct net_device *dev, u8 *da, u16 tid,
         struct ieee80211_mgmt *mgmt;
         u16 capab;
 
-        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom);
+        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom + 1 +
+                                        sizeof(mgmt->u.action.u.addba_resp));
         if (!skb) {
                 printk(KERN_DEBUG "%s: failed to allocate buffer "
                        "for addba resp frame\n", dev->name);
@@ -1047,9 +1053,14 @@ static void ieee80211_sta_process_addba_request(struct net_device *dev,
                                                 size_t len)
 {
         struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_hw *hw = &local->hw;
+        struct ieee80211_conf *conf = &hw->conf;
         struct sta_info *sta;
-        u16 capab, tid, timeout, ba_policy, buf_size, status;
+        struct tid_ampdu_rx *tid_agg_rx;
+        u16 capab, tid, timeout, ba_policy, buf_size, start_seq_num, status;
         u8 dialog_token;
+        int ret = -EOPNOTSUPP;
+        DECLARE_MAC_BUF(mac);
 
         sta = sta_info_get(local, mgmt->sa);
         if (!sta)
@@ -1058,28 +1069,216 @@ static void ieee80211_sta_process_addba_request(struct net_device *dev,
         /* extract session parameters from addba request frame */
         dialog_token = mgmt->u.action.u.addba_req.dialog_token;
         timeout = le16_to_cpu(mgmt->u.action.u.addba_req.timeout);
+        start_seq_num =
+                le16_to_cpu(mgmt->u.action.u.addba_req.start_seq_num) >> 4;
 
         capab = le16_to_cpu(mgmt->u.action.u.addba_req.capab);
         ba_policy = (capab & IEEE80211_ADDBA_PARAM_POLICY_MASK) >> 1;
         tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
         buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
 
-        /* TODO - currently aggregation is declined (A-MPDU add BA request
-        * acceptance is not obligatory by 802.11n draft), but here is
-        * the entry point for dealing with it */
-#ifdef MAC80211_HT_DEBUG
-        if (net_ratelimit())
-                printk(KERN_DEBUG "Add Block Ack request arrived,"
-                                   " currently denying it\n");
-#endif /* MAC80211_HT_DEBUG */
-
         status = WLAN_STATUS_REQUEST_DECLINED;
 
+        /* sanity check for incoming parameters:
+         * check if configuration can support the BA policy
+         * and if buffer size does not exceeds max value */
+        if (((ba_policy != 1)
+                && (!(conf->ht_conf.cap & IEEE80211_HT_CAP_DELAY_BA)))
+                || (buf_size > IEEE80211_MAX_AMPDU_BUF)) {
+                status = WLAN_STATUS_INVALID_QOS_PARAM;
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                if (net_ratelimit())
+                        printk(KERN_DEBUG "Block Ack Req with bad params from "
+                                "%s on tid %u. policy %d, buffer size %d\n",
+                                print_mac(mac, mgmt->sa), tid, ba_policy,
+                                buf_size);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                goto end_no_lock;
+        }
+        /* determine default buffer size */
+        if (buf_size == 0) {
+                struct ieee80211_hw_mode *mode = conf->mode;
+                buf_size = IEEE80211_MIN_AMPDU_BUF;
+                buf_size = buf_size << mode->ht_info.ampdu_factor;
+        }
+
+        tid_agg_rx = &sta->ampdu_mlme.tid_rx[tid];
+
+        /* examine state machine */
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
+
+        if (tid_agg_rx->state != HT_AGG_STATE_IDLE) {
+#ifdef CONFIG_MAC80211_HT_DEBUG
+                if (net_ratelimit())
+                        printk(KERN_DEBUG "unexpected Block Ack Req from "
+                                "%s on tid %u\n",
+                                print_mac(mac, mgmt->sa), tid);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+                goto end;
+        }
+
+        /* prepare reordering buffer */
+        tid_agg_rx->reorder_buf =
+                kmalloc(buf_size * sizeof(struct sk_buf *), GFP_ATOMIC);
+        if ((!tid_agg_rx->reorder_buf) && net_ratelimit()) {
+                printk(KERN_ERR "can not allocate reordering buffer "
+                                                "to tid %d\n", tid);
+                goto end;
+        }
+        memset(tid_agg_rx->reorder_buf, 0,
+                buf_size * sizeof(struct sk_buf *));
+
+        if (local->ops->ampdu_action)
+                ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_RX_START,
+                                               sta->addr, tid, start_seq_num);
+#ifdef CONFIG_MAC80211_HT_DEBUG
+        printk(KERN_DEBUG "Rx A-MPDU on tid %d result %d", tid, ret);
+#endif /* CONFIG_MAC80211_HT_DEBUG */
+
+        if (ret) {
+                kfree(tid_agg_rx->reorder_buf);
+                goto end;
+        }
+
+        /* change state and send addba resp */
+        tid_agg_rx->state = HT_AGG_STATE_OPERATIONAL;
+        tid_agg_rx->dialog_token = dialog_token;
+        tid_agg_rx->ssn = start_seq_num;
+        tid_agg_rx->head_seq_num = start_seq_num;
+        tid_agg_rx->buf_size = buf_size;
+        tid_agg_rx->timeout = timeout;
+        tid_agg_rx->stored_mpdu_num = 0;
+        status = WLAN_STATUS_SUCCESS;
+end:
+        spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+
+end_no_lock:
         ieee80211_send_addba_resp(sta->dev, sta->addr, tid, dialog_token,
                                 status, 1, buf_size, timeout);
         sta_info_put(sta);
 }
 
+void ieee80211_send_delba(struct net_device *dev, const u8 *da, u16 tid,
+                                u16 initiator, u16 reason_code)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+        struct ieee80211_if_sta *ifsta = &sdata->u.sta;
+        struct sk_buff *skb;
+        struct ieee80211_mgmt *mgmt;
+        u16 params;
+
+        skb = dev_alloc_skb(sizeof(*mgmt) + local->hw.extra_tx_headroom + 1 +
+                                        sizeof(mgmt->u.action.u.delba));
+
+        if (!skb) {
+                printk(KERN_ERR "%s: failed to allocate buffer "
+                                        "for delba frame\n", dev->name);
+                return;
+        }
+
+        skb_reserve(skb, local->hw.extra_tx_headroom);
+        mgmt = (struct ieee80211_mgmt *) skb_put(skb, 24);
+        memset(mgmt, 0, 24);
+        memcpy(mgmt->da, da, ETH_ALEN);
+        memcpy(mgmt->sa, dev->dev_addr, ETH_ALEN);
+        if (sdata->type == IEEE80211_IF_TYPE_AP)
+                memcpy(mgmt->bssid, dev->dev_addr, ETH_ALEN);
+        else
+                memcpy(mgmt->bssid, ifsta->bssid, ETH_ALEN);
+        mgmt->frame_control = IEEE80211_FC(IEEE80211_FTYPE_MGMT,
+                                        IEEE80211_STYPE_ACTION);
+
+        skb_put(skb, 1 + sizeof(mgmt->u.action.u.delba));
+
+        mgmt->u.action.category = WLAN_CATEGORY_BACK;
+        mgmt->u.action.u.delba.action_code = WLAN_ACTION_DELBA;
+        params = (u16)(initiator << 11);        /* bit 11 initiator */
+        params |= (u16)(tid << 12);             /* bit 15:12 TID number */
+
+        mgmt->u.action.u.delba.params = cpu_to_le16(params);
+        mgmt->u.action.u.delba.reason_code = cpu_to_le16(reason_code);
+
+        ieee80211_sta_tx(dev, skb, 0);
+}
+
+void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid,
+                                        u16 initiator, u16 reason)
+{
+        struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
+        struct ieee80211_hw *hw = &local->hw;
+        struct sta_info *sta;
+        int ret;
+
+        sta = sta_info_get(local, ra);
+        if (!sta)
+                return;
+
+        /* check if TID is in operational state */
+        spin_lock_bh(&sta->ampdu_mlme.ampdu_rx);
+        if (sta->ampdu_mlme.tid_rx[tid].state
+                                != HT_AGG_STATE_OPERATIONAL) {
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+                if (net_ratelimit())
+                        printk(KERN_DEBUG "rx BA session requested to stop on "
+                                "inactive tid %d\n", tid);
+                sta_info_put(sta);
+                return;
+        }
+        sta->ampdu_mlme.tid_rx[tid].state =
+                HT_AGG_STATE_REQ_STOP_BA_MSK |
+                (initiator << HT_AGG_STATE_INITIATOR_SHIFT);
+                spin_unlock_bh(&sta->ampdu_mlme.ampdu_rx);
+
+        /* stop HW Rx aggregation. ampdu_action existence
+         * already verified in session init so we add the BUG_ON */
+        BUG_ON(!local->ops->ampdu_action);
+
+        ret = local->ops->ampdu_action(hw, IEEE80211_AMPDU_RX_STOP,
+                                        ra, tid, EINVAL);
+        if (ret)
+                printk(KERN_DEBUG "HW problem - can not stop rx "
+                                "aggergation for tid %d\n", tid);
+
+        /* shutdown timer has not expired */
+        if (initiator != WLAN_BACK_TIMER)
+                del_timer_sync(&sta->ampdu_mlme.tid_rx[tid].
+                                        session_timer);
+
+        /* check if this is a self generated aggregation halt */
+        if (initiator == WLAN_BACK_RECIPIENT || initiator == WLAN_BACK_TIMER)
+                ieee80211_send_delba(dev, ra, tid, 0, reason);
+
+        /* free the reordering buffer */
+        kfree(sta->ampdu_mlme.tid_rx[tid].reorder_buf);
+
+        sta->ampdu_mlme.tid_rx[tid].state = HT_AGG_STATE_IDLE;
+        sta_info_put(sta);
+}
+
+/*
+ * After receiving Block Ack Request (BAR) we activated a
+ * timer after each frame arrives from the originator.
+ * if this timer expires ieee80211_sta_stop_rx_ba_session will be executed.
+ */
+void sta_rx_agg_session_timer_expired(unsigned long data)
+{
+        /* not an elegant detour, but there is no choice as the timer passes
+         * only one argument, and verious sta_info are needed here, so init
+         * flow in sta_info_add gives the TID as data, while the timer_to_id
+         * array gives the sta through container_of */
+        u8 *ptid = (u8 *)data;
+        u8 *timer_to_id = ptid - *ptid;
+        struct sta_info *sta = container_of(timer_to_id, struct sta_info,
+                                         timer_to_tid[0]);
+
+        printk(KERN_DEBUG "rx session timer expired on tid %d\n", (u16)*ptid);
+        ieee80211_sta_stop_rx_ba_session(sta->dev, sta->addr, (u16)*ptid,
+                                         WLAN_BACK_TIMER,
+                                         WLAN_REASON_QSTA_TIMEOUT);
+}
+
+
 static void ieee80211_rx_mgmt_auth(struct net_device *dev,
                                    struct ieee80211_if_sta *ifsta,
                                    struct ieee80211_mgmt *mgmt,
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index ffe8a49d8927..60ca07804056 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -104,6 +104,7 @@ static void sta_info_release(struct kref *kref)
         struct sta_info *sta = container_of(kref, struct sta_info, kref);
         struct ieee80211_local *local = sta->local;
         struct sk_buff *skb;
+        int i;
 
         /* free sta structure; it has already been removed from
          * hash table etc. external structures. Make sure that all
@@ -116,6 +117,8 @@ static void sta_info_release(struct kref *kref)
         while ((skb = skb_dequeue(&sta->tx_filtered)) != NULL) {
                 dev_kfree_skb_any(skb);
         }
+        for (i = 0; i <  STA_TID_NUM; i++)
+                del_timer_sync(&sta->ampdu_mlme.tid_rx[i].session_timer);
         rate_control_free_sta(sta->rate_ctrl, sta->rate_ctrl_priv);
         rate_control_put(sta->rate_ctrl);
         kfree(sta);