mac80211: move TX status handling

It's enough code to have its own file, I think.
Especially since I'm going to add to it.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 337 insertions, 0 deletions

diff --git a/net/mac80211/status.c b/net/mac80211/status.c
new file mode 100644
index 00000000000..9f91fd8e6ef
--- /dev/null
+++ b/net/mac80211/status.c
@@ -0,0 +1,337 @@
+/*
+ * Copyright 2002-2005, Instant802 Networks, Inc.
+ * Copyright 2005-2006, Devicescape Software, Inc.
+ * Copyright 2006-2007	Jiri Benc <jbenc@suse.cz>
+ * Copyright 2008-2009	Johannes Berg <johannes@sipsolutions.net>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <net/mac80211.h>
+#include "ieee80211_i.h"
+#include "rate.h"
+#include "mesh.h"
+#include "led.h"
+
+
+void ieee80211_tx_status_irqsafe(struct ieee80211_hw *hw,
+				 struct sk_buff *skb)
+{
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	int tmp;
+
+	skb->pkt_type = IEEE80211_TX_STATUS_MSG;
+	skb_queue_tail(info->flags & IEEE80211_TX_CTL_REQ_TX_STATUS ?
+		       &local->skb_queue : &local->skb_queue_unreliable, skb);
+	tmp = skb_queue_len(&local->skb_queue) +
+		skb_queue_len(&local->skb_queue_unreliable);
+	while (tmp > IEEE80211_IRQSAFE_QUEUE_LIMIT &&
+	       (skb = skb_dequeue(&local->skb_queue_unreliable))) {
+		dev_kfree_skb_irq(skb);
+		tmp--;
+		I802_DEBUG_INC(local->tx_status_drop);
+	}
+	tasklet_schedule(&local->tasklet);
+}
+EXPORT_SYMBOL(ieee80211_tx_status_irqsafe);
+
+static void ieee80211_handle_filtered_frame(struct ieee80211_local *local,
+					    struct sta_info *sta,
+					    struct sk_buff *skb)
+{
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+
+	/*
+	 * XXX: This is temporary!
+	 *
+	 *	The problem here is that when we get here, the driver will
+	 *	quite likely have pretty much overwritten info->control by
+	 *	using info->driver_data or info->rate_driver_data. Thus,
+	 *	when passing out the frame to the driver again, we would be
+	 *	passing completely bogus data since the driver would then
+	 *	expect a properly filled info->control. In mac80211 itself
+	 *	the same problem occurs, since we need info->control.vif
+	 *	internally.
+	 *
+	 *	To fix this, we should send the frame through TX processing
+	 *	again. However, it's not that simple, since the frame will
+	 *	have been software-encrypted (if applicable) already, and
+	 *	encrypting it again doesn't do much good. So to properly do
+	 *	that, we not only have to skip the actual 'raw' encryption
+	 *	(key selection etc. still has to be done!) but also the
+	 *	sequence number assignment since that impacts the crypto
+	 *	encapsulation, of course.
+	 *
+	 *	Hence, for now, fix the bug by just dropping the frame.
+	 */
+	goto drop;
+
+	sta->tx_filtered_count++;
+
+	/*
+	 * Clear the TX filter mask for this STA when sending the next
+	 * packet. If the STA went to power save mode, this will happen
+	 * when it wakes up for the next time.
+	 */
+	set_sta_flags(sta, WLAN_STA_CLEAR_PS_FILT);
+
+	/*
+	 * This code races in the following way:
+	 *
+	 *  (1) STA sends frame indicating it will go to sleep and does so
+	 *  (2) hardware/firmware adds STA to filter list, passes frame up
+	 *  (3) hardware/firmware processes TX fifo and suppresses a frame
+	 *  (4) we get TX status before having processed the frame and
+	 *	knowing that the STA has gone to sleep.
+	 *
+	 * This is actually quite unlikely even when both those events are
+	 * processed from interrupts coming in quickly after one another or
+	 * even at the same time because we queue both TX status events and
+	 * RX frames to be processed by a tasklet and process them in the
+	 * same order that they were received or TX status last. Hence, there
+	 * is no race as long as the frame RX is processed before the next TX
+	 * status, which drivers can ensure, see below.
+	 *
+	 * Note that this can only happen if the hardware or firmware can
+	 * actually add STAs to the filter list, if this is done by the
+	 * driver in response to set_tim() (which will only reduce the race
+	 * this whole filtering tries to solve, not completely solve it)
+	 * this situation cannot happen.
+	 *
+	 * To completely solve this race drivers need to make sure that they
+	 *  (a) don't mix the irq-safe/not irq-safe TX status/RX processing
+	 *	functions and
+	 *  (b) always process RX events before TX status events if ordering
+	 *      can be unknown, for example with different interrupt status
+	 *	bits.
+	 */
+	if (test_sta_flags(sta, WLAN_STA_PS_STA) &&
+	    skb_queue_len(&sta->tx_filtered) < STA_MAX_TX_BUFFER) {
+		skb_queue_tail(&sta->tx_filtered, skb);
+		return;
+	}
+
+	if (!test_sta_flags(sta, WLAN_STA_PS_STA) &&
+	    !(info->flags & IEEE80211_TX_INTFL_RETRIED)) {
+		/* Software retry the packet once */
+		info->flags |= IEEE80211_TX_INTFL_RETRIED;
+		ieee80211_add_pending_skb(local, skb);
+		return;
+	}
+
+ drop:
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+	if (net_ratelimit())
+		printk(KERN_DEBUG "%s: dropped TX filtered frame, "
+		       "queue_len=%d PS=%d @%lu\n",
+		       wiphy_name(local->hw.wiphy),
+		       skb_queue_len(&sta->tx_filtered),
+		       !!test_sta_flags(sta, WLAN_STA_PS_STA), jiffies);
+#endif
+	dev_kfree_skb(skb);
+}
+
+void ieee80211_tx_status(struct ieee80211_hw *hw, struct sk_buff *skb)
+{
+	struct sk_buff *skb2;
+	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
+	struct ieee80211_local *local = hw_to_local(hw);
+	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	u16 frag, type;
+	__le16 fc;
+	struct ieee80211_supported_band *sband;
+	struct ieee80211_tx_status_rtap_hdr *rthdr;
+	struct ieee80211_sub_if_data *sdata;
+	struct net_device *prev_dev = NULL;
+	struct sta_info *sta;
+	int retry_count = -1, i;
+
+	for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
+		/* the HW cannot have attempted that rate */
+		if (i >= hw->max_rates) {
+			info->status.rates[i].idx = -1;
+			info->status.rates[i].count = 0;
+		}
+
+		retry_count += info->status.rates[i].count;
+	}
+	if (retry_count < 0)
+		retry_count = 0;
+
+	rcu_read_lock();
+
+	sband = local->hw.wiphy->bands[info->band];
+
+	sta = sta_info_get(local, hdr->addr1);
+
+	if (sta) {
+		if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
+		    test_sta_flags(sta, WLAN_STA_PS_STA)) {
+			/*
+			 * The STA is in power save mode, so assume
+			 * that this TX packet failed because of that.
+			 */
+			ieee80211_handle_filtered_frame(local, sta, skb);
+			rcu_read_unlock();
+			return;
+		}
+
+		fc = hdr->frame_control;
+
+		if ((info->flags & IEEE80211_TX_STAT_AMPDU_NO_BACK) &&
+		    (ieee80211_is_data_qos(fc))) {
+			u16 tid, ssn;
+			u8 *qc;
+
+			qc = ieee80211_get_qos_ctl(hdr);
+			tid = qc[0] & 0xf;
+			ssn = ((le16_to_cpu(hdr->seq_ctrl) + 0x10)
+						& IEEE80211_SCTL_SEQ);
+			ieee80211_send_bar(sta->sdata, hdr->addr1,
+					   tid, ssn);
+		}
+
+		if (info->flags & IEEE80211_TX_STAT_TX_FILTERED) {
+			ieee80211_handle_filtered_frame(local, sta, skb);
+			rcu_read_unlock();
+			return;
+		} else {
+			if (!(info->flags & IEEE80211_TX_STAT_ACK))
+				sta->tx_retry_failed++;
+			sta->tx_retry_count += retry_count;
+		}
+
+		rate_control_tx_status(local, sband, sta, skb);
+		if (ieee80211_vif_is_mesh(&sta->sdata->vif))
+			ieee80211s_update_metric(local, sta, skb);
+	}
+
+	rcu_read_unlock();
+
+	ieee80211_led_tx(local, 0);
+
+	/* SNMP counters
+	 * Fragments are passed to low-level drivers as separate skbs, so these
+	 * are actually fragments, not frames. Update frame counters only for
+	 * the first fragment of the frame. */
+
+	frag = le16_to_cpu(hdr->seq_ctrl) & IEEE80211_SCTL_FRAG;
+	type = le16_to_cpu(hdr->frame_control) & IEEE80211_FCTL_FTYPE;
+
+	if (info->flags & IEEE80211_TX_STAT_ACK) {
+		if (frag == 0) {
+			local->dot11TransmittedFrameCount++;
+			if (is_multicast_ether_addr(hdr->addr1))
+				local->dot11MulticastTransmittedFrameCount++;
+			if (retry_count > 0)
+				local->dot11RetryCount++;
+			if (retry_count > 1)
+				local->dot11MultipleRetryCount++;
+		}
+
+		/* This counter shall be incremented for an acknowledged MPDU
+		 * with an individual address in the address 1 field or an MPDU
+		 * with a multicast address in the address 1 field of type Data
+		 * or Management. */
+		if (!is_multicast_ether_addr(hdr->addr1) ||
+		    type == IEEE80211_FTYPE_DATA ||
+		    type == IEEE80211_FTYPE_MGMT)
+			local->dot11TransmittedFragmentCount++;
+	} else {
+		if (frag == 0)
+			local->dot11FailedCount++;
+	}
+
+	/* this was a transmitted frame, but now we want to reuse it */
+	skb_orphan(skb);
+
+	/*
+	 * This is a bit racy but we can avoid a lot of work
+	 * with this test...
+	 */
+	if (!local->monitors && !local->cooked_mntrs) {
+		dev_kfree_skb(skb);
+		return;
+	}
+
+	/* send frame to monitor interfaces now */
+
+	if (skb_headroom(skb) < sizeof(*rthdr)) {
+		printk(KERN_ERR "ieee80211_tx_status: headroom too small\n");
+		dev_kfree_skb(skb);
+		return;
+	}
+
+	rthdr = (struct ieee80211_tx_status_rtap_hdr *)
+				skb_push(skb, sizeof(*rthdr));
+
+	memset(rthdr, 0, sizeof(*rthdr));
+	rthdr->hdr.it_len = cpu_to_le16(sizeof(*rthdr));
+	rthdr->hdr.it_present =
+		cpu_to_le32((1 << IEEE80211_RADIOTAP_TX_FLAGS) |
+			    (1 << IEEE80211_RADIOTAP_DATA_RETRIES) |
+			    (1 << IEEE80211_RADIOTAP_RATE));
+
+	if (!(info->flags & IEEE80211_TX_STAT_ACK) &&
+	    !is_multicast_ether_addr(hdr->addr1))
+		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_FAIL);
+
+	/*
+	 * XXX: Once radiotap gets the bitmap reset thing the vendor
+	 *	extensions proposal contains, we can actually report
+	 *	the whole set of tries we did.
+	 */
+	if ((info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS) ||
+	    (info->status.rates[0].flags & IEEE80211_TX_RC_USE_CTS_PROTECT))
+		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_CTS);
+	else if (info->status.rates[0].flags & IEEE80211_TX_RC_USE_RTS_CTS)
+		rthdr->tx_flags |= cpu_to_le16(IEEE80211_RADIOTAP_F_TX_RTS);
+	if (info->status.rates[0].idx >= 0 &&
+	    !(info->status.rates[0].flags & IEEE80211_TX_RC_MCS))
+		rthdr->rate = sband->bitrates[
+				info->status.rates[0].idx].bitrate / 5;
+
+	/* for now report the total retry_count */
+	rthdr->data_retries = retry_count;
+
+	/* XXX: is this sufficient for BPF? */
+	skb_set_mac_header(skb, 0);
+	skb->ip_summed = CHECKSUM_UNNECESSARY;
+	skb->pkt_type = PACKET_OTHERHOST;
+	skb->protocol = htons(ETH_P_802_2);
+	memset(skb->cb, 0, sizeof(skb->cb));
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(sdata, &local->interfaces, list) {
+		if (sdata->vif.type == NL80211_IFTYPE_MONITOR) {
+			if (!netif_running(sdata->dev))
+				continue;
+
+			if ((sdata->u.mntr_flags & MONITOR_FLAG_COOK_FRAMES) &&
+			    !(info->flags & IEEE80211_TX_CTL_INJECTED) &&
+			    (type == IEEE80211_FTYPE_DATA))
+				continue;
+
+			if (prev_dev) {
+				skb2 = skb_clone(skb, GFP_ATOMIC);
+				if (skb2) {
+					skb2->dev = prev_dev;
+					netif_rx(skb2);
+				}
+			}
+
+			prev_dev = sdata->dev;
+		}
+	}
+	if (prev_dev) {
+		skb->dev = prev_dev;
+		netif_rx(skb);
+		skb = NULL;
+	}
+	rcu_read_unlock();
+	dev_kfree_skb(skb);
+}
+EXPORT_SYMBOL(ieee80211_tx_status);