From b580781e038968fb2529460e8b61e3bf77de112a Mon Sep 17 00:00:00 2001 From: Ron Rindjunsky Date: Tue, 25 Dec 2007 17:00:35 +0200 Subject: [PATCH] mac80211: A-MPDU Rx handling aggregation reordering This patch handles the reordering of the Rx A-MPDU. This issue occurs when the sequence of the internal MPDUs is not in the right order. such a case can be encountered for example when some MPDUs from previous aggregations were recieved, while others failed, so current A-MPDU will contain a mix of re-transmited MPDUs and new ones. Signed-off-by: Ron Rindjunsky Signed-off-by: John W. Linville Signed-off-by: David S. Miller --- net/mac80211/ieee80211_sta.c | 10 +- net/mac80211/rx.c | 185 ++++++++++++++++++++++++++++++++++- 2 files changed, 192 insertions(+), 3 deletions(-) diff --git a/net/mac80211/ieee80211_sta.c b/net/mac80211/ieee80211_sta.c index d5a7683fab..f1edaa0c0d 100644 --- a/net/mac80211/ieee80211_sta.c +++ b/net/mac80211/ieee80211_sta.c @@ -1208,7 +1208,7 @@ void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid, struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr); struct ieee80211_hw *hw = &local->hw; struct sta_info *sta; - int ret; + int ret, i; sta = sta_info_get(local, ra); if (!sta) @@ -1250,6 +1250,14 @@ void ieee80211_sta_stop_rx_ba_session(struct net_device *dev, u8 *ra, u16 tid, ieee80211_send_delba(dev, ra, tid, 0, reason); /* free the reordering buffer */ + for (i = 0; i < sta->ampdu_mlme.tid_rx[tid].buf_size; i++) { + if (sta->ampdu_mlme.tid_rx[tid].reorder_buf[i]) { + /* release the reordered frames */ + dev_kfree_skb(sta->ampdu_mlme.tid_rx[tid].reorder_buf[i]); + sta->ampdu_mlme.tid_rx[tid].stored_mpdu_num--; + sta->ampdu_mlme.tid_rx[tid].reorder_buf[i] = NULL; + } + } kfree(sta->ampdu_mlme.tid_rx[tid].reorder_buf); sta->ampdu_mlme.tid_rx[tid].state = HT_AGG_STATE_IDLE; diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index a58a94b214..e7b1eb8da2 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -330,7 +330,6 @@ u32 ieee80211_rx_load_stats(struct ieee80211_local *local, /* Divide channel_use by 8 to avoid wrapping around the counter */ load >>= CHAN_UTIL_SHIFT; - local->channel_use_raw += load; return load; } @@ -1749,6 +1748,186 @@ void __ieee80211_rx_handle_packet(struct ieee80211_hw *hw, struct sk_buff *skb, sta_info_put(sta); } +#define SEQ_MODULO 0x1000 +#define SEQ_MASK 0xfff + +static inline int seq_less(u16 sq1, u16 sq2) +{ + return (((sq1 - sq2) & SEQ_MASK) > (SEQ_MODULO >> 1)); +} + +static inline u16 seq_inc(u16 sq) +{ + return ((sq + 1) & SEQ_MASK); +} + +static inline u16 seq_sub(u16 sq1, u16 sq2) +{ + return ((sq1 - sq2) & SEQ_MASK); +} + + +u8 ieee80211_sta_manage_reorder_buf(struct ieee80211_hw *hw, + struct tid_ampdu_rx *tid_agg_rx, + struct sk_buff *skb, u16 mpdu_seq_num, + int bar_req) +{ + struct ieee80211_local *local = hw_to_local(hw); + struct ieee80211_rx_status status; + u16 head_seq_num, buf_size; + int index; + u32 pkt_load; + + buf_size = tid_agg_rx->buf_size; + head_seq_num = tid_agg_rx->head_seq_num; + + /* frame with out of date sequence number */ + if (seq_less(mpdu_seq_num, head_seq_num)) { + dev_kfree_skb(skb); + return 1; + } + + /* if frame sequence number exceeds our buffering window size or + * block Ack Request arrived - release stored frames */ + if ((!seq_less(mpdu_seq_num, head_seq_num + buf_size)) || (bar_req)) { + /* new head to the ordering buffer */ + if (bar_req) + head_seq_num = mpdu_seq_num; + else + head_seq_num = + seq_inc(seq_sub(mpdu_seq_num, buf_size)); + /* release stored frames up to new head to stack */ + while (seq_less(tid_agg_rx->head_seq_num, head_seq_num)) { + index = seq_sub(tid_agg_rx->head_seq_num, + tid_agg_rx->ssn) + % tid_agg_rx->buf_size; + + if (tid_agg_rx->reorder_buf[index]) { + /* release the reordered frames to stack */ + memcpy(&status, + tid_agg_rx->reorder_buf[index]->cb, + sizeof(status)); + pkt_load = ieee80211_rx_load_stats(local, + tid_agg_rx->reorder_buf[index], + &status); + __ieee80211_rx_handle_packet(hw, + tid_agg_rx->reorder_buf[index], + &status, pkt_load); + tid_agg_rx->stored_mpdu_num--; + tid_agg_rx->reorder_buf[index] = NULL; + } + tid_agg_rx->head_seq_num = + seq_inc(tid_agg_rx->head_seq_num); + } + if (bar_req) + return 1; + } + + /* now the new frame is always in the range of the reordering */ + /* buffer window */ + index = seq_sub(mpdu_seq_num, tid_agg_rx->ssn) + % tid_agg_rx->buf_size; + /* check if we already stored this frame */ + if (tid_agg_rx->reorder_buf[index]) { + dev_kfree_skb(skb); + return 1; + } + + /* if arrived mpdu is in the right order and nothing else stored */ + /* release it immediately */ + if (mpdu_seq_num == tid_agg_rx->head_seq_num && + tid_agg_rx->stored_mpdu_num == 0) { + tid_agg_rx->head_seq_num = + seq_inc(tid_agg_rx->head_seq_num); + return 0; + } + + /* put the frame in the reordering buffer */ + tid_agg_rx->reorder_buf[index] = skb; + tid_agg_rx->stored_mpdu_num++; + /* release the buffer until next missing frame */ + index = seq_sub(tid_agg_rx->head_seq_num, tid_agg_rx->ssn) + % tid_agg_rx->buf_size; + while (tid_agg_rx->reorder_buf[index]) { + /* release the reordered frame back to stack */ + memcpy(&status, tid_agg_rx->reorder_buf[index]->cb, + sizeof(status)); + pkt_load = ieee80211_rx_load_stats(local, + tid_agg_rx->reorder_buf[index], + &status); + __ieee80211_rx_handle_packet(hw, tid_agg_rx->reorder_buf[index], + &status, pkt_load); + tid_agg_rx->stored_mpdu_num--; + tid_agg_rx->reorder_buf[index] = NULL; + tid_agg_rx->head_seq_num = seq_inc(tid_agg_rx->head_seq_num); + index = seq_sub(tid_agg_rx->head_seq_num, + tid_agg_rx->ssn) % tid_agg_rx->buf_size; + } + return 1; +} + +u8 ieee80211_rx_reorder_ampdu(struct ieee80211_local *local, + struct sk_buff *skb) +{ + struct ieee80211_hw *hw = &local->hw; + struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; + struct sta_info *sta; + struct tid_ampdu_rx *tid_agg_rx; + u16 fc, sc; + u16 mpdu_seq_num; + u8 ret = 0, *qc; + int tid; + + sta = sta_info_get(local, hdr->addr2); + if (!sta) + return ret; + + fc = le16_to_cpu(hdr->frame_control); + + /* filter the QoS data rx stream according to + * STA/TID and check if this STA/TID is on aggregation */ + if (!WLAN_FC_IS_QOS_DATA(fc)) + goto end_reorder; + + qc = skb->data + ieee80211_get_hdrlen(fc) - QOS_CONTROL_LEN; + tid = qc[0] & QOS_CONTROL_TID_MASK; + tid_agg_rx = &(sta->ampdu_mlme.tid_rx[tid]); + + if (tid_agg_rx->state != HT_AGG_STATE_OPERATIONAL) + goto end_reorder; + + /* null data frames are excluded */ + if (unlikely(fc & IEEE80211_STYPE_QOS_NULLFUNC)) + goto end_reorder; + + /* new un-ordered ampdu frame - process it */ + + /* reset session timer */ + if (tid_agg_rx->timeout) { + unsigned long expires = + jiffies + (tid_agg_rx->timeout / 1000) * HZ; + mod_timer(&tid_agg_rx->session_timer, expires); + } + + /* if this mpdu is fragmented - terminate rx aggregation session */ + sc = le16_to_cpu(hdr->seq_ctrl); + if (sc & IEEE80211_SCTL_FRAG) { + ieee80211_sta_stop_rx_ba_session(sta->dev, sta->addr, + tid, 0, WLAN_REASON_QSTA_REQUIRE_SETUP); + ret = 1; + goto end_reorder; + } + + /* according to mpdu sequence number deal with reordering buffer */ + mpdu_seq_num = (sc & IEEE80211_SCTL_SEQ) >> 4; + ret = ieee80211_sta_manage_reorder_buf(hw, tid_agg_rx, skb, + mpdu_seq_num, 0); +end_reorder: + if (sta) + sta_info_put(sta); + return ret; +} + /* * This is the receive path handler. It is called by a low level driver when an * 802.11 MPDU is received from the hardware. @@ -1779,8 +1958,10 @@ void __ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb, } pkt_load = ieee80211_rx_load_stats(local, skb, status); + local->channel_use_raw += pkt_load; - __ieee80211_rx_handle_packet(hw, skb, status, pkt_load); + if (!ieee80211_rx_reorder_ampdu(local, skb)) + __ieee80211_rx_handle_packet(hw, skb, status, pkt_load); rcu_read_unlock(); } -- 2.39.5