path: root/package/kernel/mac80211/patches/346-mac80211-Move-reorder-sensitive-TX-handlers-to-after.patch

From: Felix Fietkau <nbd@nbd.name>
Date: Sun, 4 Sep 2016 17:46:24 +0200
Subject: [PATCH] mac80211: fix sequence number assignment for PS response
 frames

When using intermediate queues, sequence number allocation is deferred
until dequeue. This doesn't work for PS response frames, which bypass
those queues.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -38,6 +38,12 @@
 #include "wme.h"
 #include "rate.h"
 
+static int invoke_tx_handlers_late(struct ieee80211_tx_data *tx);
+static bool ieee80211_xmit_fast_finish(struct ieee80211_sub_if_data *sdata,
+				       struct sta_info *sta, u8 pn_offs,
+				       struct ieee80211_key_conf *key_conf,
+				       struct sk_buff *skb);
+
 /* misc utils */
 
 static inline void ieee80211_tx_stats(struct net_device *dev, u32 len)
@@ -849,8 +855,7 @@ ieee80211_tx_h_sequence(struct ieee80211
 	tid = *qc & IEEE80211_QOS_CTL_TID_MASK;
 	tx->sta->tx_stats.msdu[tid]++;
 
-	if (!tx->sta->sta.txq[0])
-		hdr->seq_ctrl = ieee80211_tx_next_seq(tx->sta, tid);
+	hdr->seq_ctrl = ieee80211_tx_next_seq(tx->sta, tid);
 
 	return TX_CONTINUE;
 }
@@ -1398,6 +1403,7 @@ void ieee80211_txq_init(struct ieee80211
 	fq_tin_init(&txqi->tin);
 	fq_flow_init(&txqi->def_flow);
 	codel_vars_init(&txqi->def_cvars);
+	__skb_queue_head_init(&txqi->frags);
 
 	txqi->txq.vif = &sdata->vif;
 
@@ -1420,6 +1426,7 @@ void ieee80211_txq_purge(struct ieee8021
 	struct fq_tin *tin = &txqi->tin;
 
 	fq_tin_reset(fq, tin, fq_skb_free_func);
+	ieee80211_purge_tx_queue(&local->hw, &txqi->frags);
 }
 
 int ieee80211_txq_setup_flows(struct ieee80211_local *local)
@@ -1476,12 +1483,19 @@ struct sk_buff *ieee80211_tx_dequeue(str
 	struct sk_buff *skb = NULL;
 	struct fq *fq = &local->fq;
 	struct fq_tin *tin = &txqi->tin;
+	struct ieee80211_tx_info *info;
 
 	spin_lock_bh(&fq->lock);
 
 	if (test_bit(IEEE80211_TXQ_STOP, &txqi->flags))
 		goto out;
 
+	/* Make sure fragments stay together. */
+	skb = __skb_dequeue(&txqi->frags);
+	if (skb)
+		goto out;
+
+begin:
 	skb = fq_tin_dequeue(fq, tin, fq_tin_dequeue_func);
 	if (!skb)
 		goto out;
@@ -1489,16 +1503,38 @@ struct sk_buff *ieee80211_tx_dequeue(str
 	ieee80211_set_skb_vif(skb, txqi);
 
 	hdr = (struct ieee80211_hdr *)skb->data;
-	if (txq->sta && ieee80211_is_data_qos(hdr->frame_control)) {
+	info = IEEE80211_SKB_CB(skb);
+	if (txq->sta && info->control.flags & IEEE80211_TX_CTRL_FAST_XMIT) {
 		struct sta_info *sta = container_of(txq->sta, struct sta_info,
 						    sta);
-		struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+		u8 pn_offs = 0;
 
-		hdr->seq_ctrl = ieee80211_tx_next_seq(sta, txq->tid);
-		if (test_bit(IEEE80211_TXQ_AMPDU, &txqi->flags))
-			info->flags |= IEEE80211_TX_CTL_AMPDU;
-		else
-			info->flags &= ~IEEE80211_TX_CTL_AMPDU;
+		if (info->control.hw_key)
+			pn_offs = ieee80211_padded_hdrlen(hw, hdr->frame_control);
+
+		ieee80211_xmit_fast_finish(sta->sdata, sta, pn_offs,
+					   info->control.hw_key, skb);
+	} else {
+		struct ieee80211_tx_data tx = { };
+
+		__skb_queue_head_init(&tx.skbs);
+		tx.local = local;
+		tx.skb = skb;
+		tx.hdrlen = ieee80211_padded_hdrlen(hw, hdr->frame_control);
+		if (txq->sta) {
+			tx.sta = container_of(txq->sta, struct sta_info, sta);
+			tx.sdata = tx.sta->sdata;
+		} else {
+			tx.sdata = vif_to_sdata(info->control.vif);
+		}
+
+		if (invoke_tx_handlers_late(&tx))
+			goto begin;
+
+		skb = __skb_dequeue(&tx.skbs);
+
+		if (!skb_queue_empty(&tx.skbs))
+			skb_queue_splice_tail(&tx.skbs, &txqi->frags);
 	}
 
 out:
@@ -1512,6 +1548,47 @@ out:
 }
 EXPORT_SYMBOL(ieee80211_tx_dequeue);
 
+static bool ieee80211_queue_skb(struct ieee80211_local *local,
+				struct ieee80211_sub_if_data *sdata,
+				struct sta_info *sta,
+				struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct fq *fq = &local->fq;
+	struct ieee80211_vif *vif;
+	struct txq_info *txqi;
+	struct ieee80211_sta *pubsta;
+
+	if (!local->ops->wake_tx_queue ||
+	    sdata->vif.type == NL80211_IFTYPE_MONITOR)
+		return false;
+
+	if (sta && sta->uploaded)
+		pubsta = &sta->sta;
+	else
+		pubsta = NULL;
+
+	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+		sdata = container_of(sdata->bss,
+				     struct ieee80211_sub_if_data, u.ap);
+
+	vif = &sdata->vif;
+	txqi = ieee80211_get_txq(local, vif, pubsta, skb);
+
+	if (!txqi)
+		return false;
+
+	info->control.vif = vif;
+
+	spin_lock_bh(&fq->lock);
+	ieee80211_txq_enqueue(local, txqi, skb);
+	spin_unlock_bh(&fq->lock);
+
+	drv_wake_tx_queue(local, txqi);
+
+	return true;
+}
+
 static bool ieee80211_tx_frags(struct ieee80211_local *local,
 			       struct ieee80211_vif *vif,
 			       struct ieee80211_sta *sta,
@@ -1519,9 +1596,7 @@ static bool ieee80211_tx_frags(struct ie
 			       bool txpending)
 {
 	struct ieee80211_tx_control control = {};
-	struct fq *fq = &local->fq;
 	struct sk_buff *skb, *tmp;
-	struct txq_info *txqi;
 	unsigned long flags;
 
 	skb_queue_walk_safe(skbs, skb, tmp) {
@@ -1536,21 +1611,6 @@ static bool ieee80211_tx_frags(struct ie
 		}
 #endif
 
-		txqi = ieee80211_get_txq(local, vif, sta, skb);
-		if (txqi) {
-			info->control.vif = vif;
-
-			__skb_unlink(skb, skbs);
-
-			spin_lock_bh(&fq->lock);
-			ieee80211_txq_enqueue(local, txqi, skb);
-			spin_unlock_bh(&fq->lock);
-
-			drv_wake_tx_queue(local, txqi);
-
-			continue;
-		}
-
 		spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
 		if (local->queue_stop_reasons[q] ||
 		    (!txpending && !skb_queue_empty(&local->pending[q]))) {
@@ -1671,10 +1731,13 @@ static bool __ieee80211_tx(struct ieee80
 /*
  * Invoke TX handlers, return 0 on success and non-zero if the
  * frame was dropped or queued.
+ *
+ * The handlers are split into an early and late part. The latter is everything
+ * that can be sensitive to reordering, and will be deferred to after packets
+ * are dequeued from the intermediate queues (when they are enabled).
  */
-static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
+static int invoke_tx_handlers_early(struct ieee80211_tx_data *tx)
 {
-	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
 	ieee80211_tx_result res = TX_DROP;
 
 #define CALL_TXH(txh) \
@@ -1688,16 +1751,42 @@ static int invoke_tx_handlers(struct iee
 	CALL_TXH(ieee80211_tx_h_check_assoc);
 	CALL_TXH(ieee80211_tx_h_ps_buf);
 	CALL_TXH(ieee80211_tx_h_check_control_port_protocol);
-	CALL_TXH(ieee80211_tx_h_select_key);
+
 	if (!ieee80211_hw_check(&tx->local->hw, HAS_RATE_CONTROL))
 		CALL_TXH(ieee80211_tx_h_rate_ctrl);
 
+ txh_done:
+	if (unlikely(res == TX_DROP)) {
+		I802_DEBUG_INC(tx->local->tx_handlers_drop);
+		if (tx->skb)
+			ieee80211_free_txskb(&tx->local->hw, tx->skb);
+		else
+			ieee80211_purge_tx_queue(&tx->local->hw, &tx->skbs);
+		return -1;
+	} else if (unlikely(res == TX_QUEUED)) {
+		I802_DEBUG_INC(tx->local->tx_handlers_queued);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*
+ * Late handlers can be called while the sta lock is held. Handlers that can
+ * cause packets to be generated will cause deadlock!
+ */
+static int invoke_tx_handlers_late(struct ieee80211_tx_data *tx)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(tx->skb);
+	ieee80211_tx_result res = TX_CONTINUE;
+
 	if (unlikely(info->flags & IEEE80211_TX_INTFL_RETRANSMISSION)) {
 		__skb_queue_tail(&tx->skbs, tx->skb);
 		tx->skb = NULL;
 		goto txh_done;
 	}
 
+	CALL_TXH(ieee80211_tx_h_select_key);
 	CALL_TXH(ieee80211_tx_h_michael_mic_add);
 	CALL_TXH(ieee80211_tx_h_sequence);
 	CALL_TXH(ieee80211_tx_h_fragment);
@@ -1724,6 +1813,15 @@ static int invoke_tx_handlers(struct iee
 	return 0;
 }
 
+static int invoke_tx_handlers(struct ieee80211_tx_data *tx)
+{
+	int r = invoke_tx_handlers_early(tx);
+	if (r)
+		return r;
+
+	return invoke_tx_handlers_late(tx);
+}
+
 bool ieee80211_tx_prepare_skb(struct ieee80211_hw *hw,
 			      struct ieee80211_vif *vif, struct sk_buff *skb,
 			      int band, struct ieee80211_sta **sta)
@@ -1798,7 +1896,13 @@ static bool ieee80211_tx(struct ieee8021
 		info->hw_queue =
 			sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
 
-	if (!invoke_tx_handlers(&tx))
+	if (invoke_tx_handlers_early(&tx))
+		return false;
+
+	if (ieee80211_queue_skb(local, sdata, tx.sta, tx.skb))
+		return true;
+
+	if (!invoke_tx_handlers_late(&tx))
 		result = __ieee80211_tx(local, &tx.skbs, led_len,
 					tx.sta, txpending);
 
@@ -3181,7 +3285,7 @@ out:
 }
 
 static bool ieee80211_xmit_fast(struct ieee80211_sub_if_data *sdata,
-				struct net_device *dev, struct sta_info *sta,
+				struct sta_info *sta,
 				struct ieee80211_fast_tx *fast_tx,
 				struct sk_buff *skb)
 {
@@ -3192,9 +3296,9 @@ static bool ieee80211_xmit_fast(struct i
 	struct ethhdr eth;
 	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
 	struct ieee80211_hdr *hdr = (void *)fast_tx->hdr;
-	struct ieee80211_tx_data tx;
-	ieee80211_tx_result r;
 	struct tid_ampdu_tx *tid_tx = NULL;
+	ieee80211_tx_result r;
+	struct ieee80211_tx_data tx;
 	u8 tid = IEEE80211_NUM_TIDS;
 
 	/* control port protocol needs a lot of special handling */
@@ -3232,8 +3336,6 @@ static bool ieee80211_xmit_fast(struct i
 			return true;
 	}
 
-	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;
@@ -3262,24 +3364,7 @@ static bool ieee80211_xmit_fast(struct i
 	info->flags = IEEE80211_TX_CTL_FIRST_FRAGMENT |
 		      IEEE80211_TX_CTL_DONTFRAG |
 		      (tid_tx ? IEEE80211_TX_CTL_AMPDU : 0);
-
-	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
-		*ieee80211_get_qos_ctl(hdr) = tid;
-		if (!sta->sta.txq[0])
-			hdr->seq_ctrl = ieee80211_tx_next_seq(sta, tid);
-	} else {
-		info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
-		hdr->seq_ctrl = cpu_to_le16(sdata->sequence_number);
-		sdata->sequence_number += 0x10;
-	}
-
-	if (skb_shinfo(skb)->gso_size)
-		sta->tx_stats.msdu[tid] +=
-			DIV_ROUND_UP(skb->len, skb_shinfo(skb)->gso_size);
-	else
-		sta->tx_stats.msdu[tid]++;
-
-	info->hw_queue = sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
+	info->control.flags = IEEE80211_TX_CTRL_FAST_XMIT;
 
 	__skb_queue_head_init(&tx.skbs);
 
@@ -3305,22 +3390,71 @@ static bool ieee80211_xmit_fast(struct i
 		}
 	}
 
+	if (ieee80211_queue_skb(local, sdata, sta, skb))
+		return true;
+
+	ieee80211_xmit_fast_finish(sdata, sta, fast_tx->pn_offs,
+				   &fast_tx->key->conf, skb);
+
+	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
+		sdata = container_of(sdata->bss,
+				     struct ieee80211_sub_if_data, u.ap);
+
+	__skb_queue_tail(&tx.skbs, skb);
+	ieee80211_tx_frags(local, &sdata->vif, &sta->sta, &tx.skbs, false);
+
+	return true;
+}
+
+/*
+ * Can be called while the sta lock is held. Anything that can cause packets to
+ * be generated will cause deadlock!
+ */
+static bool ieee80211_xmit_fast_finish(struct ieee80211_sub_if_data *sdata,
+				       struct sta_info *sta, u8 pn_offs,
+				       struct ieee80211_key_conf *key_conf,
+				       struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *hdr = (void *)skb->data;
+	u8 tid = IEEE80211_NUM_TIDS;
+
+	ieee80211_tx_stats(skb->dev, skb->len);
+
+	if (hdr->frame_control & cpu_to_le16(IEEE80211_STYPE_QOS_DATA)) {
+		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
+		*ieee80211_get_qos_ctl(hdr) = tid;
+		hdr->seq_ctrl = ieee80211_tx_next_seq(sta, tid);
+	} else {
+		info->flags |= IEEE80211_TX_CTL_ASSIGN_SEQ;
+		hdr->seq_ctrl = cpu_to_le16(sdata->sequence_number);
+		sdata->sequence_number += 0x10;
+	}
+
+	if (skb_shinfo(skb)->gso_size)
+		sta->tx_stats.msdu[tid] +=
+			DIV_ROUND_UP(skb->len, skb_shinfo(skb)->gso_size);
+	else
+		sta->tx_stats.msdu[tid]++;
+
+	info->hw_queue = sdata->vif.hw_queue[skb_get_queue_mapping(skb)];
+
 	/* statistics normally done by ieee80211_tx_h_stats (but that
 	 * has to consider fragmentation, so is more complex)
 	 */
 	sta->tx_stats.bytes[skb_get_queue_mapping(skb)] += skb->len;
 	sta->tx_stats.packets[skb_get_queue_mapping(skb)]++;
 
-	if (fast_tx->pn_offs) {
+	if (pn_offs) {
 		u64 pn;
-		u8 *crypto_hdr = skb->data + fast_tx->pn_offs;
+		u8 *crypto_hdr = skb->data + pn_offs;
 
-		switch (fast_tx->key->conf.cipher) {
+		switch (key_conf->cipher) {
 		case WLAN_CIPHER_SUITE_CCMP:
 		case WLAN_CIPHER_SUITE_CCMP_256:
 		case WLAN_CIPHER_SUITE_GCMP:
 		case WLAN_CIPHER_SUITE_GCMP_256:
-			pn = atomic64_inc_return(&fast_tx->key->conf.tx_pn);
+			pn = atomic64_inc_return(&key_conf->tx_pn);
 			crypto_hdr[0] = pn;
 			crypto_hdr[1] = pn >> 8;
 			crypto_hdr[4] = pn >> 16;
@@ -3331,12 +3465,6 @@ static bool ieee80211_xmit_fast(struct i
 		}
 	}
 
-	if (sdata->vif.type == NL80211_IFTYPE_AP_VLAN)
-		sdata = container_of(sdata->bss,
-				     struct ieee80211_sub_if_data, u.ap);
-
-	__skb_queue_tail(&tx.skbs, skb);
-	ieee80211_tx_frags(local, &sdata->vif, &sta->sta, &tx.skbs, false);
 	return true;
 }
 
@@ -3364,7 +3492,7 @@ void __ieee80211_subif_start_xmit(struct
 		fast_tx = rcu_dereference(sta->fast_tx);
 
 		if (fast_tx &&
-		    ieee80211_xmit_fast(sdata, dev, sta, fast_tx, skb))
+		    ieee80211_xmit_fast(sdata, sta, fast_tx, skb))
 			goto out;
 	}
 
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -715,6 +715,7 @@ enum mac80211_tx_info_flags {
  *	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
+ * @IEEE80211_TX_CTRL_FAST_XMIT: This frame is going through the fast_xmit path
  *
  * These flags are used in tx_info->control.flags.
  */
@@ -723,6 +724,7 @@ enum mac80211_tx_control_flags {
 	IEEE80211_TX_CTRL_PS_RESPONSE		= BIT(1),
 	IEEE80211_TX_CTRL_RATE_INJECT		= BIT(2),
 	IEEE80211_TX_CTRL_AMSDU			= BIT(3),
+	IEEE80211_TX_CTRL_FAST_XMIT		= BIT(4),
 };
 
 /*
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -814,11 +814,13 @@ enum txq_info_flags {
  * @def_flow: used as a fallback flow when a packet destined to @tin hashes to
  *	a fq_flow which is already owned by a different tin
  * @def_cvars: codel vars for @def_flow
+ * @frags: used to keep fragments created after dequeue
  */
 struct txq_info {
 	struct fq_tin tin;
 	struct fq_flow def_flow;
 	struct codel_vars def_cvars;
+	struct sk_buff_head frags;
 	unsigned long flags;
 
 	/* keep last! */