diff mbox

[RFC] mac80211: add A-MSDU tx support

Message ID 1454632843-74700-1-git-send-email-nbd@openwrt.org (mailing list archive)
State RFC
Delegated to: Johannes Berg
Headers show

Commit Message

Felix Fietkau Feb. 5, 2016, 12:40 a.m. UTC
Requires software tx queueing support. frag_list support (for zero-copy)
is optional.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
---
 include/net/mac80211.h     |  10 ++++
 net/mac80211/agg-tx.c      |   5 ++
 net/mac80211/debugfs.c     |   2 +
 net/mac80211/ieee80211_i.h |   1 +
 net/mac80211/tx.c          | 136 +++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 154 insertions(+)
diff mbox

Patch

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 5714774..c221220 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -709,6 +709,7 @@  enum mac80211_tx_info_flags {
  * @IEEE80211_TX_CTRL_PS_RESPONSE: This frame is a response to a poll
  *	frame (PS-Poll or uAPSD).
  * @IEEE80211_TX_CTRL_RATE_INJECT: This frame is injected with rate information
+ * @IEEE80211_TX_CTRL_AMSDU: This frame is an A-MSDU frame
  *
  * These flags are used in tx_info->control.flags.
  */
@@ -716,6 +717,7 @@  enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTRL_PORT_CTRL_PROTO	= BIT(0),
 	IEEE80211_TX_CTRL_PS_RESPONSE		= BIT(1),
 	IEEE80211_TX_CTRL_RATE_INJECT		= BIT(2),
+	IEEE80211_TX_CTRL_AMSDU			= BIT(3),
 };
 
 /*
@@ -1964,6 +1966,12 @@  struct ieee80211_txq {
  *	order and does not need to manage its own reorder buffer or BA session
  *	timeout.
  *
+ * @IEEE80211_HW_TX_AMSDU: Hardware (or driver) supports software aggregated
+ *	A-MSDU frames. Requires software tx queueing support.
+ *
+ * @IEEE80211_HW_TX_FRAG_LIST: Hardware (or driver) supports sending frag_list
+ *	skbs, needed for zero-copy software A-MSDU.
+ *
  * @NUM_IEEE80211_HW_FLAGS: number of hardware flags, used for sizing arrays
  */
 enum ieee80211_hw_flags {
@@ -2001,6 +2009,8 @@  enum ieee80211_hw_flags {
 	IEEE80211_HW_BEACON_TX_STATUS,
 	IEEE80211_HW_NEEDS_UNIQUE_STA_ADDR,
 	IEEE80211_HW_SUPPORTS_REORDERING_BUFFER,
+	IEEE80211_HW_TX_AMSDU,
+	IEEE80211_HW_TX_FRAG_LIST,
 
 	/* keep last, obviously */
 	NUM_IEEE80211_HW_FLAGS
diff --git a/net/mac80211/agg-tx.c b/net/mac80211/agg-tx.c
index 4932e9f..42fa810 100644
--- a/net/mac80211/agg-tx.c
+++ b/net/mac80211/agg-tx.c
@@ -935,6 +935,7 @@  void ieee80211_process_addba_resp(struct ieee80211_local *local,
 				  size_t len)
 {
 	struct tid_ampdu_tx *tid_tx;
+	struct ieee80211_txq *txq;
 	u16 capab, tid;
 	u8 buf_size;
 	bool amsdu;
@@ -945,6 +946,10 @@  void ieee80211_process_addba_resp(struct ieee80211_local *local,
 	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);
diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
index e433d0c..847779d 100644
--- a/net/mac80211/debugfs.c
+++ b/net/mac80211/debugfs.c
@@ -127,6 +127,8 @@  static const char *hw_flag_names[NUM_IEEE80211_HW_FLAGS + 1] = {
 	FLAG(BEACON_TX_STATUS),
 	FLAG(NEEDS_UNIQUE_STA_ADDR),
 	FLAG(SUPPORTS_REORDERING_BUFFER),
+	FLAG(TX_AMSDU),
+	FLAG(TX_FRAG_LIST),
 
 	/* keep last for the build bug below */
 	(void *)0x1
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index a49c103..e68d8db 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -799,6 +799,7 @@  struct mac80211_qos_map {
 enum txq_info_flags {
 	IEEE80211_TXQ_STOP,
 	IEEE80211_TXQ_AMPDU,
+	IEEE80211_TXQ_NO_AMSDU,
 };
 
 struct txq_info {
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index a5aa275..a4fe5bb 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1324,6 +1324,10 @@  struct sk_buff *ieee80211_tx_dequeue(struct ieee80211_hw *hw,
 out:
 	spin_unlock_bh(&txqi->queue.lock);
 
+	if (skb && skb_has_frag_list(skb) &&
+	    !ieee80211_hw_check(&local->hw, TX_FRAG_LIST))
+		skb_linearize(skb);
+
 	return skb;
 }
 EXPORT_SYMBOL(ieee80211_tx_dequeue);
@@ -2763,6 +2767,134 @@  void ieee80211_clear_fast_xmit(struct sta_info *sta)
 		kfree_rcu(fast_tx, rcu_head);
 }
 
+static int ieee80211_amsdu_pad(struct sk_buff *skb, int subframe_len)
+{
+	int amsdu_len = subframe_len + sizeof(struct ethhdr);
+	int padding = (4 - amsdu_len) & 3;
+
+	if (padding)
+		memset(skb_put(skb, padding), 0, padding);
+
+	return padding;
+}
+
+static bool ieee80211_amsdu_prepare_head(struct ieee80211_sub_if_data *sdata,
+					 struct ieee80211_fast_tx *fast_tx,
+					 struct sk_buff *skb)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *hdr;
+	struct ethhdr amsdu_hdr;
+	int hdr_len = fast_tx->hdr_len - sizeof(rfc1042_header);
+	int subframe_len = skb->len - hdr_len;
+	void *data;
+	u8 *qc;
+
+	if (info->control.flags & IEEE80211_TX_CTRL_AMSDU)
+		return true;
+
+	if (skb_headroom(skb) < sizeof(amsdu_hdr) || skb_tailroom(skb) < 3) {
+		I802_DEBUG_INC(local->tx_expand_skb_head);
+
+		if (pskb_expand_head(skb, sizeof(amsdu_hdr), 3, GFP_ATOMIC)) {
+			wiphy_debug(local->hw.wiphy,
+				    "failed to reallocate TX buffer\n");
+			return false;
+		}
+	}
+
+	subframe_len += ieee80211_amsdu_pad(skb, subframe_len);
+
+	amsdu_hdr.h_proto = cpu_to_be16(subframe_len);
+	memcpy(amsdu_hdr.h_source, skb->data + fast_tx->sa_offs, ETH_ALEN);
+	memcpy(amsdu_hdr.h_dest, skb->data + fast_tx->da_offs, ETH_ALEN);
+
+	data = skb_push(skb, sizeof(amsdu_hdr));
+	memmove(data, data + sizeof(amsdu_hdr), hdr_len);
+	memcpy(data + hdr_len, &amsdu_hdr, sizeof(amsdu_hdr));
+
+	hdr = data;
+	qc = ieee80211_get_qos_ctl(hdr);
+	*qc |= IEEE80211_QOS_CTL_A_MSDU_PRESENT;
+
+	info->control.flags |= IEEE80211_TX_CTRL_AMSDU;
+
+	return true;
+}
+
+static bool ieee80211_amsdu_aggregate(struct ieee80211_sub_if_data *sdata,
+				      struct sta_info *sta,
+				      struct ieee80211_fast_tx *fast_tx,
+				      struct sk_buff *skb)
+{
+	struct ieee80211_local *local = sdata->local;
+	u8 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
+	struct ieee80211_txq *txq = sta->sta.txq[tid];
+	struct txq_info *txqi;
+	struct sk_buff **frag_tail, *head;
+	int subframe_len = skb->len - ETH_ALEN;
+	__be16 len;
+	void *data;
+	bool ret = false;
+
+	if (!ieee80211_hw_check(&local->hw, TX_AMSDU))
+		return false;
+
+	if (!txq)
+		return false;
+
+	txqi = to_txq_info(txq);
+	if (test_bit(IEEE80211_TXQ_NO_AMSDU, &txqi->flags))
+		return false;
+
+	spin_lock_bh(&txqi->queue.lock);
+
+	head = skb_peek_tail(&txqi->queue);
+	if (!head)
+		goto out;
+
+	if (skb->len + head->len > sta->sta.max_amsdu_len)
+		goto out;
+
+	if (!ieee80211_amsdu_prepare_head(sdata, fast_tx, head))
+		goto out;
+
+	if (skb_headroom(skb) < 8 || skb_tailroom(skb) < 3) {
+		I802_DEBUG_INC(local->tx_expand_skb_head);
+
+		if (pskb_expand_head(skb, 8, 3, GFP_ATOMIC)) {
+			wiphy_debug(local->hw.wiphy,
+				    "failed to reallocate TX buffer\n");
+			return false;
+		}
+	}
+
+	subframe_len += ieee80211_amsdu_pad(skb, subframe_len);
+
+	ret = true;
+	data = skb_push(skb, ETH_ALEN + 2);
+	memmove(data, data + ETH_ALEN + 2, 2 * ETH_ALEN);
+
+	data += 2 * ETH_ALEN;
+	len = cpu_to_be16(subframe_len);
+	memcpy(data, &len, 2);
+	memcpy(data + 2, rfc1042_header, ETH_ALEN);
+
+	frag_tail = &skb_shinfo(head)->frag_list;
+	while (*frag_tail)
+	     frag_tail = &(*frag_tail)->next;
+
+	head->len += skb->len;
+	head->data_len += skb->len;
+	*frag_tail = skb;
+
+out:
+	spin_unlock_bh(&txqi->queue.lock);
+
+	return ret;
+}
+
 static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
 				struct net_device *dev, struct sta_info *sta,
 				struct ieee80211_fast_tx *fast_tx,
@@ -2817,6 +2949,10 @@  static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
 
 	ieee80211_tx_stats(dev, skb->len + extra_head);
 
+	if ((hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) &&
+	    ieee80211_amsdu_aggregate(sdata, sta, fast_tx, skb))
+		return true;
+
 	/* will not be crypto-handled beyond what we do here, so use false
 	 * as the may-encrypt argument for the resize to not account for
 	 * more room than we already have in 'extra_head'