Beispiel #1
0
/**
 * mesh_path_error_tx - Sends a PERR mesh management frame
 *
 * @ttl: allowed remaining hops
 * @target: broken destination
 * @target_sn: SN of the broken destination
 * @target_rcode: reason code for this PERR
 * @ra: node this frame is addressed to
 * @sdata: local mesh subif
 *
 * Note: This function may be called with driver locks taken that the driver
 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 * frame directly but add it to the pending queue instead.
 */
int mesh_path_error_tx(struct ieee80211_sub_if_data *sdata,
		       u8 ttl, const u8 *target, u32 target_sn,
		       u16 target_rcode, const u8 *ra)
{
	struct ieee80211_local *local = sdata->local;
	struct sk_buff *skb;
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
	struct ieee80211_mgmt *mgmt;
	u8 *pos, ie_len;
	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
		      sizeof(mgmt->u.action.u.mesh_action);

	if (time_before(jiffies, ifmsh->next_perr))
		return -EAGAIN;

	skb = dev_alloc_skb(local->tx_headroom +
			    sdata->encrypt_headroom +
			    IEEE80211_ENCRYPT_TAILROOM +
			    hdr_len +
			    2 + 15 /* PERR IE */);
	if (!skb)
		return -1;
	skb_reserve(skb, local->tx_headroom + sdata->encrypt_headroom);
	mgmt = skb_put_zero(skb, hdr_len);
	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_ACTION);

	memcpy(mgmt->da, ra, ETH_ALEN);
	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
	/* BSSID == SA */
	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
	mgmt->u.action.u.mesh_action.action_code =
					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
	ie_len = 15;
	pos = skb_put(skb, 2 + ie_len);
	*pos++ = WLAN_EID_PERR;
	*pos++ = ie_len;
	/* ttl */
	*pos++ = ttl;
	/* number of destinations */
	*pos++ = 1;
	/* Flags field has AE bit only as defined in
	 * sec 8.4.2.117 IEEE802.11-2012
	 */
	*pos = 0;
	pos++;
	memcpy(pos, target, ETH_ALEN);
	pos += ETH_ALEN;
	put_unaligned_le32(target_sn, pos);
	pos += 4;
	put_unaligned_le16(target_rcode, pos);

	/* see note in function header */
	prepare_frame_for_deferred_tx(sdata, skb);
	ifmsh->next_perr = TU_TO_EXP_TIME(
				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
	ieee80211_add_pending_skb(local, skb);
	return 0;
}
Beispiel #2
0
/**
 * hwmp_route_info_get - Update routing info to originator and transmitter
 *
 * @sdata: local mesh subif
 * @mgmt: mesh management frame
 * @hwmp_ie: hwmp information element (PREP or PREQ)
 *
 * This function updates the path routing information to the originator and the
 * transmitter of a HWMP PREQ or PREP fram.
 *
 * Returns: metric to frame originator or 0 if the frame should not be further
 * processed
 *
 * Notes: this function is the only place (besides user-provided info) where
 * path routing information is updated.
 */
static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
			    struct ieee80211_mgmt *mgmt,
			    u8 *hwmp_ie)
{
	struct ieee80211_local *local = sdata->local;
	struct mesh_path *mpath;
	struct sta_info *sta;
	bool fresh_info;
	u8 *orig_addr, *ta;
	u32 orig_dsn, orig_metric;
	unsigned long orig_lifetime, exp_time;
	u32 last_hop_metric, new_metric;
	bool process = true;
	u8 action = mgmt->u.action.u.mesh_action.action_code;

	rcu_read_lock();
	sta = sta_info_get(local, mgmt->sa);
	if (!sta) {
		rcu_read_unlock();
		return 0;
	}

	last_hop_metric = airtime_link_metric_get(local, sta);
	/* Update and check originator routing info */
	fresh_info = true;

	switch (action) {
	case MPATH_PREQ:
		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
		orig_dsn = PREQ_IE_ORIG_DSN(hwmp_ie);
		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
		orig_metric = PREQ_IE_METRIC(hwmp_ie);
		break;
	case MPATH_PREP:
		/* Originator here refers to the MP that was the destination in
		 * the Path Request. The draft refers to that MP as the
		 * destination address, even though usually it is the origin of
		 * the PREP frame. We divert from the nomenclature in the draft
		 * so that we can easily use a single function to gather path
		 * information from both PREQ and PREP frames.
		 */
		orig_addr = PREP_IE_ORIG_ADDR(hwmp_ie);
		orig_dsn = PREP_IE_ORIG_DSN(hwmp_ie);
		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
		orig_metric = PREP_IE_METRIC(hwmp_ie);
		break;
	default:
		rcu_read_unlock();
		return 0;
	}
	new_metric = orig_metric + last_hop_metric;
	if (new_metric < orig_metric)
		new_metric = MAX_METRIC;
	exp_time = TU_TO_EXP_TIME(orig_lifetime);

	if (memcmp(orig_addr, sdata->dev->dev_addr, ETH_ALEN) == 0) {
		/* This MP is the originator, we are not interested in this
		 * frame, except for updating transmitter's path info.
		 */
		process = false;
		fresh_info = false;
	} else {
		mpath = mesh_path_lookup(orig_addr, sdata);
		if (mpath) {
			spin_lock_bh(&mpath->state_lock);
			if (mpath->flags & MESH_PATH_FIXED)
				fresh_info = false;
			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
			    (mpath->flags & MESH_PATH_DSN_VALID)) {
				if (DSN_GT(mpath->dsn, orig_dsn) ||
				    (mpath->dsn == orig_dsn &&
				     action == MPATH_PREQ &&
				     new_metric > mpath->metric)) {
					process = false;
					fresh_info = false;
				}
			}
		} else {
			mesh_path_add(orig_addr, sdata);
			mpath = mesh_path_lookup(orig_addr, sdata);
			if (!mpath) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->flags |= MESH_PATH_DSN_VALID;
			mpath->metric = new_metric;
			mpath->dsn = orig_dsn;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_tx_pending(mpath);
			/* draft says preq_id should be saved to, but there does
			 * not seem to be any use for it, skipping by now
			 */
		} else
			spin_unlock_bh(&mpath->state_lock);
	}

	/* Update and check transmitter routing info */
	ta = mgmt->sa;
	if (memcmp(orig_addr, ta, ETH_ALEN) == 0)
		fresh_info = false;
	else {
		fresh_info = true;

		mpath = mesh_path_lookup(ta, sdata);
		if (mpath) {
			spin_lock_bh(&mpath->state_lock);
			if ((mpath->flags & MESH_PATH_FIXED) ||
				((mpath->flags & MESH_PATH_ACTIVE) &&
					(last_hop_metric > mpath->metric)))
				fresh_info = false;
		} else {
			mesh_path_add(ta, sdata);
			mpath = mesh_path_lookup(ta, sdata);
			if (!mpath) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->flags &= ~MESH_PATH_DSN_VALID;
			mpath->metric = last_hop_metric;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			mesh_path_tx_pending(mpath);
		} else
			spin_unlock_bh(&mpath->state_lock);
	}

	rcu_read_unlock();

	return process ? new_metric : 0;
}
void ieee80211_process_addba_resp(struct ieee80211_local *local,
                                  struct sta_info *sta,
                                  struct ieee80211_mgmt *mgmt,
                                  size_t len)
{
    struct tid_ampdu_tx *tid_tx;
    u16 capab, tid;
    u8 buf_size;

    capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
    tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
    buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;

    mutex_lock(&sta->ampdu_mlme.mtx);

    tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
    if (!tid_tx)
        goto out;

    if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
#ifdef CONFIG_MAC80211_HT_DEBUG
        printk(KERN_DEBUG "wrong addBA response token, tid %d\n", tid);
#endif
        goto out;
    }

    del_timer_sync(&tid_tx->addba_resp_timer);

#ifdef CONFIG_MAC80211_HT_DEBUG
    printk(KERN_DEBUG "switched off addBA timer for tid %d\n", tid);
#endif

    /*
     * addba_resp_timer may have fired before we got here, and
     * caused WANT_STOP to be set. If the stop then was already
     * processed further, STOPPING might be set.
     */
    if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
            test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
#ifdef CONFIG_MAC80211_HT_DEBUG
        printk(KERN_DEBUG
               "got addBA resp for tid %d but we already gave up\n",
               tid);
#endif
        goto out;
    }

    /*
     * IEEE 802.11-2007 7.3.1.14:
     * In an ADDBA Response frame, when the Status Code field
     * is set to 0, the Buffer Size subfield is set to a value
     * of at least 1.
     */
    if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
            == WLAN_STATUS_SUCCESS && buf_size) {
        if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
                             &tid_tx->state)) {
            /* ignore duplicate response */
            goto out;
        }

        tid_tx->buf_size = buf_size;

        if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
            ieee80211_agg_tx_operational(local, sta, tid);

        sta->ampdu_mlme.addba_req_num[tid] = 0;

        if (tid_tx->timeout) {
            mod_timer(&tid_tx->session_timer,
                      TU_TO_EXP_TIME(tid_tx->timeout));
            tid_tx->last_tx = jiffies;
        }

    } else {
        ___ieee80211_stop_tx_ba_session(sta, tid, WLAN_BACK_INITIATOR,
                                        true);
    }

out:
    mutex_unlock(&sta->ampdu_mlme.mtx);
}
/**
 * mesh_path_error_tx - Sends a PERR mesh management frame
 *
 * @ttl: allowed remaining hops
 * @target: broken destination
 * @target_sn: SN of the broken destination
 * @target_rcode: reason code for this PERR
 * @ra: node this frame is addressed to
 * @sdata: local mesh subif
 *
 * Note: This function may be called with driver locks taken that the driver
 * also acquires in the TX path.  To avoid a deadlock we don't transmit the
 * frame directly but add it to the pending queue instead.
 */
int mesh_path_error_tx(u8 ttl, u8 *target, __le32 target_sn,
		       __le16 target_rcode, const u8 *ra,
		       struct ieee80211_sub_if_data *sdata)
{
	struct ieee80211_local *local = sdata->local;
	struct sk_buff *skb;
	struct ieee80211_if_mesh *ifmsh = &sdata->u.mesh;
	struct ieee80211_mgmt *mgmt;
	u8 *pos, ie_len;
	int hdr_len = offsetof(struct ieee80211_mgmt, u.action.u.mesh_action) +
		      sizeof(mgmt->u.action.u.mesh_action);

	if (time_before(jiffies, ifmsh->next_perr))
		return -EAGAIN;

	skb = dev_alloc_skb(local->tx_headroom +
			    IEEE80211_ENCRYPT_HEADROOM +
			    IEEE80211_ENCRYPT_TAILROOM +
			    hdr_len +
			    2 + 15 /* PERR IE */);
	if (!skb)
		return -1;
	skb_reserve(skb, local->tx_headroom + IEEE80211_ENCRYPT_HEADROOM);
	mgmt = (struct ieee80211_mgmt *) skb_put(skb, hdr_len);
	memset(mgmt, 0, hdr_len);
	mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
					  IEEE80211_STYPE_ACTION);

	memcpy(mgmt->da, ra, ETH_ALEN);
	memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
	/* BSSID == SA */
	memcpy(mgmt->bssid, sdata->vif.addr, ETH_ALEN);
	mgmt->u.action.category = WLAN_CATEGORY_MESH_ACTION;
	mgmt->u.action.u.mesh_action.action_code =
					WLAN_MESH_ACTION_HWMP_PATH_SELECTION;
	ie_len = 15;
	pos = skb_put(skb, 2 + ie_len);
	*pos++ = WLAN_EID_PERR;
	*pos++ = ie_len;
	/* ttl */
	*pos++ = ttl;
	/* number of destinations */
	*pos++ = 1;
	/*
	 * flags bit, bit 1 is unset if we know the sequence number and
	 * bit 2 is set if we have a reason code
	 */
	*pos = 0;
	if (!target_sn)
		*pos |= MP_F_USN;
	if (target_rcode)
		*pos |= MP_F_RCODE;
	pos++;
	memcpy(pos, target, ETH_ALEN);
	pos += ETH_ALEN;
	memcpy(pos, &target_sn, 4);
	pos += 4;
	memcpy(pos, &target_rcode, 2);

	/* see note in function header */
	prepare_frame_for_deferred_tx(sdata, skb);
	ifmsh->next_perr = TU_TO_EXP_TIME(
				   ifmsh->mshcfg.dot11MeshHWMPperrMinInterval);
	ieee80211_add_pending_skb(local, skb);
	return 0;
}
Beispiel #5
0
/**
 * hwmp_route_info_get - Update routing info to originator and transmitter
 *
 * @sdata: local mesh subif
 * @mgmt: mesh management frame
 * @hwmp_ie: hwmp information element (PREP or PREQ)
 * @action: type of hwmp ie
 *
 * This function updates the path routing information to the originator and the
 * transmitter of a HWMP PREQ or PREP frame.
 *
 * Returns: metric to frame originator or 0 if the frame should not be further
 * processed
 *
 * Notes: this function is the only place (besides user-provided info) where
 * path routing information is updated.
 */
static u32 hwmp_route_info_get(struct ieee80211_sub_if_data *sdata,
			       struct ieee80211_mgmt *mgmt,
			       const u8 *hwmp_ie, enum mpath_frame_type action)
{
	struct ieee80211_local *local = sdata->local;
	struct mesh_path *mpath;
	struct sta_info *sta;
	bool fresh_info;
	const u8 *orig_addr, *ta;
	u32 orig_sn, orig_metric;
	unsigned long orig_lifetime, exp_time;
	u32 last_hop_metric, new_metric;
	bool process = true;

	rcu_read_lock();
	sta = sta_info_get(sdata, mgmt->sa);
	if (!sta) {
		rcu_read_unlock();
		return 0;
	}

	last_hop_metric = airtime_link_metric_get(local, sta);
	/* Update and check originator routing info */
	fresh_info = true;

	switch (action) {
	case MPATH_PREQ:
		orig_addr = PREQ_IE_ORIG_ADDR(hwmp_ie);
		orig_sn = PREQ_IE_ORIG_SN(hwmp_ie);
		orig_lifetime = PREQ_IE_LIFETIME(hwmp_ie);
		orig_metric = PREQ_IE_METRIC(hwmp_ie);
		break;
	case MPATH_PREP:
		/* Originator here refers to the MP that was the target in the
		 * Path Request. We divert from the nomenclature in the draft
		 * so that we can easily use a single function to gather path
		 * information from both PREQ and PREP frames.
		 */
		orig_addr = PREP_IE_TARGET_ADDR(hwmp_ie);
		orig_sn = PREP_IE_TARGET_SN(hwmp_ie);
		orig_lifetime = PREP_IE_LIFETIME(hwmp_ie);
		orig_metric = PREP_IE_METRIC(hwmp_ie);
		break;
	default:
		rcu_read_unlock();
		return 0;
	}
	new_metric = orig_metric + last_hop_metric;
	if (new_metric < orig_metric)
		new_metric = MAX_METRIC;
	exp_time = TU_TO_EXP_TIME(orig_lifetime);

	if (ether_addr_equal(orig_addr, sdata->vif.addr)) {
		/* This MP is the originator, we are not interested in this
		 * frame, except for updating transmitter's path info.
		 */
		process = false;
		fresh_info = false;
	} else {
		mpath = mesh_path_lookup(sdata, orig_addr);
		if (mpath) {
			spin_lock_bh(&mpath->state_lock);
			if (mpath->flags & MESH_PATH_FIXED)
				fresh_info = false;
			else if ((mpath->flags & MESH_PATH_ACTIVE) &&
			    (mpath->flags & MESH_PATH_SN_VALID)) {
				if (SN_GT(mpath->sn, orig_sn) ||
				    (mpath->sn == orig_sn &&
				     new_metric >= mpath->metric)) {
					process = false;
					fresh_info = false;
				}
			} else if (!(mpath->flags & MESH_PATH_ACTIVE)) {
				bool have_sn, newer_sn, bounced;

				have_sn = mpath->flags & MESH_PATH_SN_VALID;
				newer_sn = have_sn && SN_GT(orig_sn, mpath->sn);
				bounced = have_sn &&
					  (SN_DELTA(orig_sn, mpath->sn) >
							MAX_SANE_SN_DELTA);

				if (!have_sn || newer_sn) {
					/* if SN is newer than what we had
					 * then we can take it */;
				} else if (bounced) {
					/* if SN is way different than what
					 * we had then assume the other side
					 * rebooted or restarted */;
				} else {
					process = false;
					fresh_info = false;
				}
			}
		} else {
			mpath = mesh_path_add(sdata, orig_addr);
			if (IS_ERR(mpath)) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->flags |= MESH_PATH_SN_VALID;
			mpath->metric = new_metric;
			mpath->sn = orig_sn;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
			/* init it at a low value - 0 start is tricky */
			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
			mesh_path_tx_pending(mpath);
			/* draft says preq_id should be saved to, but there does
			 * not seem to be any use for it, skipping by now
			 */
		} else
			spin_unlock_bh(&mpath->state_lock);
	}

	/* Update and check transmitter routing info */
	ta = mgmt->sa;
	if (ether_addr_equal(orig_addr, ta))
		fresh_info = false;
	else {
		fresh_info = true;

		mpath = mesh_path_lookup(sdata, ta);
		if (mpath) {
			spin_lock_bh(&mpath->state_lock);
			if ((mpath->flags & MESH_PATH_FIXED) ||
				((mpath->flags & MESH_PATH_ACTIVE) &&
					(last_hop_metric > mpath->metric)))
				fresh_info = false;
		} else {
			mpath = mesh_path_add(sdata, ta);
			if (IS_ERR(mpath)) {
				rcu_read_unlock();
				return 0;
			}
			spin_lock_bh(&mpath->state_lock);
		}

		if (fresh_info) {
			mesh_path_assign_nexthop(mpath, sta);
			mpath->metric = last_hop_metric;
			mpath->exp_time = time_after(mpath->exp_time, exp_time)
					  ?  mpath->exp_time : exp_time;
			mesh_path_activate(mpath);
			spin_unlock_bh(&mpath->state_lock);
			ewma_mesh_fail_avg_init(&sta->mesh->fail_avg);
			/* init it at a low value - 0 start is tricky */
			ewma_mesh_fail_avg_add(&sta->mesh->fail_avg, 1);
			mesh_path_tx_pending(mpath);
		} else
			spin_unlock_bh(&mpath->state_lock);
	}

	rcu_read_unlock();

	return process ? new_metric : 0;
}
Beispiel #6
0
int ___ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
				    enum ieee80211_agg_stop_reason reason)
{
	struct ieee80211_local *local = sta->local;
	struct tid_ampdu_tx *tid_tx;
	struct ieee80211_ampdu_params params = {
		.sta = &sta->sta,
		.tid = tid,
		.buf_size = 0,
		.amsdu = false,
		.timeout = 0,
		.ssn = 0,
	};
	int ret;

	lockdep_assert_held(&sta->ampdu_mlme.mtx);

	switch (reason) {
	case AGG_STOP_DECLINED:
	case AGG_STOP_LOCAL_REQUEST:
	case AGG_STOP_PEER_REQUEST:
		params.action = IEEE80211_AMPDU_TX_STOP_CONT;
		break;
	case AGG_STOP_DESTROY_STA:
		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH;
		break;
	default:
		WARN_ON_ONCE(1);
		return -EINVAL;
	}

	spin_lock_bh(&sta->lock);

	/* free struct pending for start, if present */
	tid_tx = sta->ampdu_mlme.tid_start_tx[tid];
	kfree(tid_tx);
	sta->ampdu_mlme.tid_start_tx[tid] = NULL;

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
	if (!tid_tx) {
		spin_unlock_bh(&sta->lock);
		return -ENOENT;
	}

	/*
	 * if we're already stopping ignore any new requests to stop
	 * unless we're destroying it in which case notify the driver
	 */
	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		spin_unlock_bh(&sta->lock);
		if (reason != AGG_STOP_DESTROY_STA)
			return -EALREADY;
		params.action = IEEE80211_AMPDU_TX_STOP_FLUSH_CONT;
		ret = drv_ampdu_action(local, sta->sdata, &params);
		WARN_ON_ONCE(ret);
		return 0;
	}

	if (test_bit(HT_AGG_STATE_WANT_START, &tid_tx->state)) {
		/* not even started yet! */
		ieee80211_assign_tid_tx(sta, tid, NULL);
		spin_unlock_bh(&sta->lock);
		kfree_rcu(tid_tx, rcu_head);
		return 0;
	}

	set_bit(HT_AGG_STATE_STOPPING, &tid_tx->state);

	spin_unlock_bh(&sta->lock);

	ht_dbg(sta->sdata, "Tx BA session stop requested for %pM tid %u\n",
	       sta->sta.addr, tid);

	del_timer_sync(&tid_tx->addba_resp_timer);
	del_timer_sync(&tid_tx->session_timer);

	/*
	 * After this packets are no longer handed right through
	 * to the driver but are put onto tid_tx->pending instead,
	 * with locking to ensure proper access.
	 */
	clear_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);

	/*
	 * There might be a few packets being processed right now (on
	 * another CPU) that have already gotten past the aggregation
	 * check when it was still OPERATIONAL and consequently have
	 * IEEE80211_TX_CTL_AMPDU set. In that case, this code might
	 * call into the driver at the same time or even before the
	 * TX paths calls into it, which could confuse the driver.
	 *
	 * Wait for all currently running TX paths to finish before
	 * telling the driver. New packets will not go through since
	 * the aggregation session is no longer OPERATIONAL.
	 */
	synchronize_net();

	tid_tx->stop_initiator = reason == AGG_STOP_PEER_REQUEST ?
					WLAN_BACK_RECIPIENT :
					WLAN_BACK_INITIATOR;
	tid_tx->tx_stop = reason == AGG_STOP_LOCAL_REQUEST;

	ret = drv_ampdu_action(local, sta->sdata, &params);

	/* HW shall not deny going back to legacy */
	if (WARN_ON(ret)) {
		/*
		 * We may have pending packets get stuck in this case...
		 * Not bothering with a workaround for now.
		 */
	}

	/*
	 * In the case of AGG_STOP_DESTROY_STA, the driver won't
	 * necessarily call ieee80211_stop_tx_ba_cb(), so this may
	 * seem like we can leave the tid_tx data pending forever.
	 * This is true, in a way, but "forever" is only until the
	 * station struct is actually destroyed. In the meantime,
	 * leaving it around ensures that we don't transmit packets
	 * to the driver on this TID which might confuse it.
	 */

	return 0;
}

/*
 * After sending add Block Ack request we activated a timer until
 * add Block Ack response will arrive from the recipient.
 * If this timer expires sta_addba_resp_timer_expired will be executed.
 */
static void sta_addba_resp_timer_expired(struct timer_list *t)
{
	struct tid_ampdu_tx *tid_tx_timer =
		from_timer(tid_tx_timer, t, addba_resp_timer);
	struct sta_info *sta = tid_tx_timer->sta;
	u8 tid = tid_tx_timer->tid;
	struct tid_ampdu_tx *tid_tx;

	/* check if the TID waits for addBA response */
	rcu_read_lock();
	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx ||
	    test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state)) {
		rcu_read_unlock();
		ht_dbg(sta->sdata,
		       "timer expired on %pM tid %d not expecting addBA response\n",
		       sta->sta.addr, tid);
		return;
	}

	ht_dbg(sta->sdata, "addBA response timer expired on %pM tid %d\n",
	       sta->sta.addr, tid);

	ieee80211_stop_tx_ba_session(&sta->sta, tid);
	rcu_read_unlock();
}

void ieee80211_tx_ba_session_handle_start(struct sta_info *sta, int tid)
{
	struct tid_ampdu_tx *tid_tx;
	struct ieee80211_local *local = sta->local;
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct ieee80211_ampdu_params params = {
		.sta = &sta->sta,
		.action = IEEE80211_AMPDU_TX_START,
		.tid = tid,
		.buf_size = 0,
		.amsdu = false,
		.timeout = 0,
	};
	int ret;

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);

	/*
	 * Start queuing up packets for this aggregation session.
	 * We're going to release them once the driver is OK with
	 * that.
	 */
	clear_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);

	ieee80211_agg_stop_txq(sta, tid);

	/*
	 * Make sure no packets are being processed. This ensures that
	 * we have a valid starting sequence number and that in-flight
	 * packets have been flushed out and no packets for this TID
	 * will go into the driver during the ampdu_action call.
	 */
	synchronize_net();

	params.ssn = sta->tid_seq[tid] >> 4;
	ret = drv_ampdu_action(local, sdata, &params);
	if (ret) {
		ht_dbg(sdata,
		       "BA request denied - HW unavailable for %pM tid %d\n",
		       sta->sta.addr, tid);
		spin_lock_bh(&sta->lock);
		ieee80211_agg_splice_packets(sdata, tid_tx, tid);
		ieee80211_assign_tid_tx(sta, tid, NULL);
		ieee80211_agg_splice_finish(sdata, tid);
		spin_unlock_bh(&sta->lock);

		ieee80211_agg_start_txq(sta, tid, false);

		kfree_rcu(tid_tx, rcu_head);
		return;
	}

	/* activate the timer for the recipient's addBA response */
	mod_timer(&tid_tx->addba_resp_timer, jiffies + ADDBA_RESP_INTERVAL);
	ht_dbg(sdata, "activated addBA response timer on %pM tid %d\n",
	       sta->sta.addr, tid);

	spin_lock_bh(&sta->lock);
	sta->ampdu_mlme.last_addba_req_time[tid] = jiffies;
	sta->ampdu_mlme.addba_req_num[tid]++;
	spin_unlock_bh(&sta->lock);

	/* send AddBA request */
	ieee80211_send_addba_request(sdata, sta->sta.addr, tid,
				     tid_tx->dialog_token, params.ssn,
				     IEEE80211_MAX_AMPDU_BUF,
				     tid_tx->timeout);
}

/*
 * After accepting the AddBA Response we activated a timer,
 * resetting it after each frame that we send.
 */
static void sta_tx_agg_session_timer_expired(struct timer_list *t)
{
	struct tid_ampdu_tx *tid_tx_timer =
		from_timer(tid_tx_timer, t, session_timer);
	struct sta_info *sta = tid_tx_timer->sta;
	u8 tid = tid_tx_timer->tid;
	struct tid_ampdu_tx *tid_tx;
	unsigned long timeout;

	rcu_read_lock();
	tid_tx = rcu_dereference(sta->ampdu_mlme.tid_tx[tid]);
	if (!tid_tx || test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		rcu_read_unlock();
		return;
	}

	timeout = tid_tx->last_tx + TU_TO_JIFFIES(tid_tx->timeout);
	if (time_is_after_jiffies(timeout)) {
		mod_timer(&tid_tx->session_timer, timeout);
		rcu_read_unlock();
		return;
	}

	rcu_read_unlock();

	ht_dbg(sta->sdata, "tx session timer expired on %pM tid %d\n",
	       sta->sta.addr, tid);

	ieee80211_stop_tx_ba_session(&sta->sta, tid);
}

int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid,
				  u16 timeout)
{
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct ieee80211_local *local = sdata->local;
	struct tid_ampdu_tx *tid_tx;
	int ret = 0;

	trace_api_start_tx_ba_session(pubsta, tid);

	if (WARN(sta->reserved_tid == tid,
		 "Requested to start BA session on reserved tid=%d", tid))
		return -EINVAL;

	if (!pubsta->ht_cap.ht_supported)
		return -EINVAL;

	if (WARN_ON_ONCE(!local->ops->ampdu_action))
		return -EINVAL;

	if ((tid >= IEEE80211_NUM_TIDS) ||
	    !ieee80211_hw_check(&local->hw, AMPDU_AGGREGATION) ||
	    ieee80211_hw_check(&local->hw, TX_AMPDU_SETUP_IN_HW))
		return -EINVAL;

	if (WARN_ON(tid >= IEEE80211_FIRST_TSPEC_TSID))
		return -EINVAL;

	ht_dbg(sdata, "Open BA session requested for %pM tid %u\n",
	       pubsta->addr, tid);

	if (sdata->vif.type != NL80211_IFTYPE_STATION &&
	    sdata->vif.type != NL80211_IFTYPE_MESH_POINT &&
	    sdata->vif.type != NL80211_IFTYPE_AP_VLAN &&
	    sdata->vif.type != NL80211_IFTYPE_AP &&
	    sdata->vif.type != NL80211_IFTYPE_ADHOC)
		return -EINVAL;

	if (test_sta_flag(sta, WLAN_STA_BLOCK_BA)) {
		ht_dbg(sdata,
		       "BA sessions blocked - Denying BA session request %pM tid %d\n",
		       sta->sta.addr, tid);
		return -EINVAL;
	}

	/*
	 * 802.11n-2009 11.5.1.1: If the initiating STA is an HT STA, is a
	 * member of an IBSS, and has no other existing Block Ack agreement
	 * with the recipient STA, then the initiating STA shall transmit a
	 * Probe Request frame to the recipient STA and shall not transmit an
	 * ADDBA Request frame unless it receives a Probe Response frame
	 * from the recipient within dot11ADDBAFailureTimeout.
	 *
	 * The probe request mechanism for ADDBA is currently not implemented,
	 * but we only build up Block Ack session with HT STAs. This information
	 * is set when we receive a bss info from a probe response or a beacon.
	 */
	if (sta->sdata->vif.type == NL80211_IFTYPE_ADHOC &&
	    !sta->sta.ht_cap.ht_supported) {
		ht_dbg(sdata,
		       "BA request denied - IBSS STA %pM does not advertise HT support\n",
		       pubsta->addr);
		return -EINVAL;
	}

	spin_lock_bh(&sta->lock);

	/* we have tried too many times, receiver does not want A-MPDU */
	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
		ret = -EBUSY;
		goto err_unlock_sta;
	}

	/*
	 * if we have tried more than HT_AGG_BURST_RETRIES times we
	 * will spread our requests in time to avoid stalling connection
	 * for too long
	 */
	if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_BURST_RETRIES &&
	    time_before(jiffies, sta->ampdu_mlme.last_addba_req_time[tid] +
			HT_AGG_RETRIES_PERIOD)) {
		ht_dbg(sdata,
		       "BA request denied - %d failed requests on %pM tid %u\n",
		       sta->ampdu_mlme.addba_req_num[tid], sta->sta.addr, tid);
		ret = -EBUSY;
		goto err_unlock_sta;
	}

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
	/* check if the TID is not in aggregation flow already */
	if (tid_tx || sta->ampdu_mlme.tid_start_tx[tid]) {
		ht_dbg(sdata,
		       "BA request denied - session is not idle on %pM tid %u\n",
		       sta->sta.addr, tid);
		ret = -EAGAIN;
		goto err_unlock_sta;
	}

	/* prepare A-MPDU MLME for Tx aggregation */
	tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
	if (!tid_tx) {
		ret = -ENOMEM;
		goto err_unlock_sta;
	}

	skb_queue_head_init(&tid_tx->pending);
	__set_bit(HT_AGG_STATE_WANT_START, &tid_tx->state);

	tid_tx->timeout = timeout;
	tid_tx->sta = sta;
	tid_tx->tid = tid;

	/* response timer */
	timer_setup(&tid_tx->addba_resp_timer, sta_addba_resp_timer_expired, 0);

	/* tx timer */
	timer_setup(&tid_tx->session_timer,
		    sta_tx_agg_session_timer_expired, TIMER_DEFERRABLE);

	/* assign a dialog token */
	sta->ampdu_mlme.dialog_token_allocator++;
	tid_tx->dialog_token = sta->ampdu_mlme.dialog_token_allocator;

	/*
	 * Finally, assign it to the start array; the work item will
	 * collect it and move it to the normal array.
	 */
	sta->ampdu_mlme.tid_start_tx[tid] = tid_tx;

	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);

	/* this flow continues off the work */
 err_unlock_sta:
	spin_unlock_bh(&sta->lock);
	return ret;
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_session);

static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
					 struct sta_info *sta, u16 tid)
{
	struct tid_ampdu_tx *tid_tx;
	struct ieee80211_ampdu_params params = {
		.sta = &sta->sta,
		.action = IEEE80211_AMPDU_TX_OPERATIONAL,
		.tid = tid,
		.timeout = 0,
		.ssn = 0,
	};

	lockdep_assert_held(&sta->ampdu_mlme.mtx);

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
	params.buf_size = tid_tx->buf_size;
	params.amsdu = tid_tx->amsdu;

	ht_dbg(sta->sdata, "Aggregation is on for %pM tid %d\n",
	       sta->sta.addr, tid);

	drv_ampdu_action(local, sta->sdata, &params);

	/*
	 * synchronize with TX path, while splicing the TX path
	 * should block so it won't put more packets onto pending.
	 */
	spin_lock_bh(&sta->lock);

	ieee80211_agg_splice_packets(sta->sdata, tid_tx, tid);
	/*
	 * Now mark as operational. This will be visible
	 * in the TX path, and lets it go lock-free in
	 * the common case.
	 */
	set_bit(HT_AGG_STATE_OPERATIONAL, &tid_tx->state);
	ieee80211_agg_splice_finish(sta->sdata, tid);

	spin_unlock_bh(&sta->lock);

	ieee80211_agg_start_txq(sta, tid, true);
}

void ieee80211_start_tx_ba_cb(struct sta_info *sta, int tid,
			      struct tid_ampdu_tx *tid_tx)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct ieee80211_local *local = sdata->local;

	if (WARN_ON(test_and_set_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state)))
		return;

	if (test_bit(HT_AGG_STATE_RESPONSE_RECEIVED, &tid_tx->state))
		ieee80211_agg_tx_operational(local, sta, tid);
}

static struct tid_ampdu_tx *
ieee80211_lookup_tid_tx(struct ieee80211_sub_if_data *sdata,
			const u8 *ra, u16 tid, struct sta_info **sta)
{
	struct tid_ampdu_tx *tid_tx;

	if (tid >= IEEE80211_NUM_TIDS) {
		ht_dbg(sdata, "Bad TID value: tid = %d (>= %d)\n",
		       tid, IEEE80211_NUM_TIDS);
		return NULL;
	}

	*sta = sta_info_get_bss(sdata, ra);
	if (!*sta) {
		ht_dbg(sdata, "Could not find station: %pM\n", ra);
		return NULL;
	}

	tid_tx = rcu_dereference((*sta)->ampdu_mlme.tid_tx[tid]);

	if (WARN_ON(!tid_tx))
		ht_dbg(sdata, "addBA was not requested!\n");

	return tid_tx;
}

void ieee80211_start_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
				      const u8 *ra, u16 tid)
{
	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
	struct ieee80211_local *local = sdata->local;
	struct sta_info *sta;
	struct tid_ampdu_tx *tid_tx;

	trace_api_start_tx_ba_cb(sdata, ra, tid);

	rcu_read_lock();
	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
	if (!tid_tx)
		goto out;

	set_bit(HT_AGG_STATE_START_CB, &tid_tx->state);
	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 out:
	rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_cb_irqsafe);

int __ieee80211_stop_tx_ba_session(struct sta_info *sta, u16 tid,
				   enum ieee80211_agg_stop_reason reason)
{
	int ret;

	mutex_lock(&sta->ampdu_mlme.mtx);

	ret = ___ieee80211_stop_tx_ba_session(sta, tid, reason);

	mutex_unlock(&sta->ampdu_mlme.mtx);

	return ret;
}

int ieee80211_stop_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
{
	struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	struct ieee80211_local *local = sdata->local;
	struct tid_ampdu_tx *tid_tx;
	int ret = 0;

	trace_api_stop_tx_ba_session(pubsta, tid);

	if (!local->ops->ampdu_action)
		return -EINVAL;

	if (tid >= IEEE80211_NUM_TIDS)
		return -EINVAL;

	spin_lock_bh(&sta->lock);
	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);

	if (!tid_tx) {
		ret = -ENOENT;
		goto unlock;
	}

	WARN(sta->reserved_tid == tid,
	     "Requested to stop BA session on reserved tid=%d", tid);

	if (test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		/* already in progress stopping it */
		ret = 0;
		goto unlock;
	}

	set_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state);
	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);

 unlock:
	spin_unlock_bh(&sta->lock);
	return ret;
}
EXPORT_SYMBOL(ieee80211_stop_tx_ba_session);

void ieee80211_stop_tx_ba_cb(struct sta_info *sta, int tid,
			     struct tid_ampdu_tx *tid_tx)
{
	struct ieee80211_sub_if_data *sdata = sta->sdata;
	bool send_delba = false;

	ht_dbg(sdata, "Stopping Tx BA session for %pM tid %d\n",
	       sta->sta.addr, tid);

	spin_lock_bh(&sta->lock);

	if (!test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		ht_dbg(sdata,
		       "unexpected callback to A-MPDU stop for %pM tid %d\n",
		       sta->sta.addr, tid);
		goto unlock_sta;
	}

	if (tid_tx->stop_initiator == WLAN_BACK_INITIATOR && tid_tx->tx_stop)
		send_delba = true;

	ieee80211_remove_tid_tx(sta, tid);

 unlock_sta:
	spin_unlock_bh(&sta->lock);

	if (send_delba)
		ieee80211_send_delba(sdata, sta->sta.addr, tid,
			WLAN_BACK_INITIATOR, WLAN_REASON_QSTA_NOT_USE);
}

void ieee80211_stop_tx_ba_cb_irqsafe(struct ieee80211_vif *vif,
				     const u8 *ra, u16 tid)
{
	struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
	struct ieee80211_local *local = sdata->local;
	struct sta_info *sta;
	struct tid_ampdu_tx *tid_tx;

	trace_api_stop_tx_ba_cb(sdata, ra, tid);

	rcu_read_lock();
	tid_tx = ieee80211_lookup_tid_tx(sdata, ra, tid, &sta);
	if (!tid_tx)
		goto out;

	set_bit(HT_AGG_STATE_STOP_CB, &tid_tx->state);
	ieee80211_queue_work(&local->hw, &sta->ampdu_mlme.work);
 out:
	rcu_read_unlock();
}
EXPORT_SYMBOL(ieee80211_stop_tx_ba_cb_irqsafe);


void ieee80211_process_addba_resp(struct ieee80211_local *local,
				  struct sta_info *sta,
				  struct ieee80211_mgmt *mgmt,
				  size_t len)
{
	struct tid_ampdu_tx *tid_tx;
	struct ieee80211_txq *txq;
	u16 capab, tid;
	u8 buf_size;
	bool amsdu;

	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
	amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
	buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);

	txq = sta->sta.txq[tid];
	if (!amsdu && txq)
		set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags);

	mutex_lock(&sta->ampdu_mlme.mtx);

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
	if (!tid_tx)
		goto out;

	if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
		ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
		       sta->sta.addr, tid);
		goto out;
	}

	del_timer_sync(&tid_tx->addba_resp_timer);

	ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
	       sta->sta.addr, tid);

	/*
	 * addba_resp_timer may have fired before we got here, and
	 * caused WANT_STOP to be set. If the stop then was already
	 * processed further, STOPPING might be set.
	 */
	if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
	    test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		ht_dbg(sta->sdata,
		       "got addBA resp for %pM tid %d but we already gave up\n",
		       sta->sta.addr, tid);
		goto out;
	}

	/*
	 * IEEE 802.11-2007 7.3.1.14:
	 * In an ADDBA Response frame, when the Status Code field
	 * is set to 0, the Buffer Size subfield is set to a value
	 * of at least 1.
	 */
	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
			== WLAN_STATUS_SUCCESS && buf_size) {
		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
				     &tid_tx->state)) {
			/* ignore duplicate response */
			goto out;
		}

		tid_tx->buf_size = buf_size;
		tid_tx->amsdu = amsdu;

		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
			ieee80211_agg_tx_operational(local, sta, tid);

		sta->ampdu_mlme.addba_req_num[tid] = 0;

		if (tid_tx->timeout) {
			mod_timer(&tid_tx->session_timer,
				  TU_TO_EXP_TIME(tid_tx->timeout));
			tid_tx->last_tx = jiffies;
		}

	} else {
		___ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
	}

 out:
	mutex_unlock(&sta->ampdu_mlme.mtx);
}
Beispiel #7
0
void ieee80211_process_addba_resp(struct ieee80211_local *local,
				  struct sta_info *sta,
				  struct ieee80211_mgmt *mgmt,
				  size_t len)
{
	struct tid_ampdu_tx *tid_tx;
	struct ieee80211_txq *txq;
	u16 capab, tid;
	u8 buf_size;
	bool amsdu;

	capab = le16_to_cpu(mgmt->u.action.u.addba_resp.capab);
	amsdu = capab & IEEE80211_ADDBA_PARAM_AMSDU_MASK;
	tid = (capab & IEEE80211_ADDBA_PARAM_TID_MASK) >> 2;
	buf_size = (capab & IEEE80211_ADDBA_PARAM_BUF_SIZE_MASK) >> 6;
	buf_size = min(buf_size, local->hw.max_tx_aggregation_subframes);

	txq = sta->sta.txq[tid];
	if (!amsdu && txq)
		set_bit(IEEE80211_TXQ_NO_AMSDU, &to_txq_info(txq)->flags);

	mutex_lock(&sta->ampdu_mlme.mtx);

	tid_tx = rcu_dereference_protected_tid_tx(sta, tid);
	if (!tid_tx)
		goto out;

	if (mgmt->u.action.u.addba_resp.dialog_token != tid_tx->dialog_token) {
		ht_dbg(sta->sdata, "wrong addBA response token, %pM tid %d\n",
		       sta->sta.addr, tid);
		goto out;
	}

	del_timer_sync(&tid_tx->addba_resp_timer);

	ht_dbg(sta->sdata, "switched off addBA timer for %pM tid %d\n",
	       sta->sta.addr, tid);

	/*
	 * addba_resp_timer may have fired before we got here, and
	 * caused WANT_STOP to be set. If the stop then was already
	 * processed further, STOPPING might be set.
	 */
	if (test_bit(HT_AGG_STATE_WANT_STOP, &tid_tx->state) ||
	    test_bit(HT_AGG_STATE_STOPPING, &tid_tx->state)) {
		ht_dbg(sta->sdata,
		       "got addBA resp for %pM tid %d but we already gave up\n",
		       sta->sta.addr, tid);
		goto out;
	}

	/*
	 * IEEE 802.11-2007 7.3.1.14:
	 * In an ADDBA Response frame, when the Status Code field
	 * is set to 0, the Buffer Size subfield is set to a value
	 * of at least 1.
	 */
	if (le16_to_cpu(mgmt->u.action.u.addba_resp.status)
			== WLAN_STATUS_SUCCESS && buf_size) {
		if (test_and_set_bit(HT_AGG_STATE_RESPONSE_RECEIVED,
				     &tid_tx->state)) {
			/* ignore duplicate response */
			goto out;
		}

		tid_tx->buf_size = buf_size;
		tid_tx->amsdu = amsdu;

		if (test_bit(HT_AGG_STATE_DRV_READY, &tid_tx->state))
			ieee80211_agg_tx_operational(local, sta, tid);

		sta->ampdu_mlme.addba_req_num[tid] = 0;

		if (tid_tx->timeout) {
			mod_timer(&tid_tx->session_timer,
				  TU_TO_EXP_TIME(tid_tx->timeout));
			tid_tx->last_tx = jiffies;
		}

	} else {
		___ieee80211_stop_tx_ba_session(sta, tid, AGG_STOP_DECLINED);
	}

 out:
	mutex_unlock(&sta->ampdu_mlme.mtx);
}