wme.c revision 51cb6db0f5654f08a4a6bfa3888dc36a51c2df3e 
1/*
2 * Copyright 2004, Instant802 Networks, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/netdevice.h>
10#include <linux/skbuff.h>
11#include <linux/module.h>
12#include <linux/if_arp.h>
13#include <linux/types.h>
14#include <net/ip.h>
15#include <net/pkt_sched.h>
16
17#include <net/mac80211.h>
18#include "ieee80211_i.h"
19#include "wme.h"
20
21/* Default mapping in classifier to work with default
22 * queue setup.
23 */
24const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };
25
26static const char llc_ip_hdr[8] = {0xAA, 0xAA, 0x3, 0, 0, 0, 0x08, 0};
27
28/* Given a data frame determine the 802.1p/1d tag to use.  */
29static unsigned int classify_1d(struct sk_buff *skb)
30{
31	unsigned int dscp;
32
33	/* skb->priority values from 256->263 are magic values to
34	 * directly indicate a specific 802.1d priority.  This is used
35	 * to allow 802.1d priority to be passed directly in from VLAN
36	 * tags, etc.
37	 */
38	if (skb->priority >= 256 && skb->priority <= 263)
39		return skb->priority - 256;
40
41	switch (skb->protocol) {
42	case __constant_htons(ETH_P_IP):
43		dscp = ip_hdr(skb)->tos & 0xfc;
44		break;
45
46	default:
47		return 0;
48	}
49
50	if (dscp & 0x1c)
51		return 0;
52	return dscp >> 5;
53}
54
55
56static int wme_downgrade_ac(struct sk_buff *skb)
57{
58	switch (skb->priority) {
59	case 6:
60	case 7:
61		skb->priority = 5; /* VO -> VI */
62		return 0;
63	case 4:
64	case 5:
65		skb->priority = 3; /* VI -> BE */
66		return 0;
67	case 0:
68	case 3:
69		skb->priority = 2; /* BE -> BK */
70		return 0;
71	default:
72		return -1;
73	}
74}
75
76
77/* Indicate which queue to use.  */
78static u16 classify80211(struct sk_buff *skb, struct net_device *dev)
79{
80	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
81	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
82
83	if (!ieee80211_is_data(hdr->frame_control)) {
84		/* management frames go on AC_VO queue, but are sent
85		* without QoS control fields */
86		return 0;
87	}
88
89	if (0 /* injected */) {
90		/* use AC from radiotap */
91	}
92
93	if (!ieee80211_is_data_qos(hdr->frame_control)) {
94		skb->priority = 0; /* required for correct WPA/11i MIC */
95		return ieee802_1d_to_ac[skb->priority];
96	}
97
98	/* use the data classifier to determine what 802.1d tag the
99	 * data frame has */
100	skb->priority = classify_1d(skb);
101
102	/* in case we are a client verify acm is not set for this ac */
103	while (unlikely(local->wmm_acm & BIT(skb->priority))) {
104		if (wme_downgrade_ac(skb)) {
105			/* The old code would drop the packet in this
106			 * case.
107			 */
108			return 0;
109		}
110	}
111
112	/* look up which queue to use for frames with this 1d tag */
113	return ieee802_1d_to_ac[skb->priority];
114}
115
116u16 ieee80211_select_queue(struct net_device *dev, struct sk_buff *skb)
117{
118	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
119	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
120	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
121	struct sta_info *sta;
122	u16 queue;
123	u8 tid;
124
125	queue = classify80211(skb, dev);
126	if (unlikely(queue >= local->hw.queues))
127		queue = local->hw.queues - 1;
128
129	if (info->flags & IEEE80211_TX_CTL_REQUEUE) {
130		rcu_read_lock();
131		sta = sta_info_get(local, hdr->addr1);
132		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
133		if (sta) {
134			struct ieee80211_hw *hw = &local->hw;
135			int ampdu_queue = sta->tid_to_tx_q[tid];
136
137			if ((ampdu_queue < ieee80211_num_queues(hw)) &&
138			    test_bit(ampdu_queue, local->queue_pool)) {
139				queue = ampdu_queue;
140				info->flags |= IEEE80211_TX_CTL_AMPDU;
141			} else {
142				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
143			}
144		}
145		rcu_read_unlock();
146
147		return queue;
148	}
149
150	/* Now we know the 1d priority, fill in the QoS header if
151	 * there is one.
152	 */
153	if (ieee80211_is_data_qos(hdr->frame_control)) {
154		u8 *p = ieee80211_get_qos_ctl(hdr);
155		u8 ack_policy = 0;
156		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
157		if (local->wifi_wme_noack_test)
158			ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
159					QOS_CONTROL_ACK_POLICY_SHIFT;
160		/* qos header is 2 bytes, second reserved */
161		*p++ = ack_policy | tid;
162		*p = 0;
163
164		rcu_read_lock();
165
166		sta = sta_info_get(local, hdr->addr1);
167		if (sta) {
168			int ampdu_queue = sta->tid_to_tx_q[tid];
169			struct ieee80211_hw *hw = &local->hw;
170
171			if ((ampdu_queue < ieee80211_num_queues(hw)) &&
172			    test_bit(ampdu_queue, local->queue_pool)) {
173				queue = ampdu_queue;
174				info->flags |= IEEE80211_TX_CTL_AMPDU;
175			} else {
176				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
177			}
178		}
179
180		rcu_read_unlock();
181	}
182
183	return queue;
184}
185
186int ieee80211_ht_agg_queue_add(struct ieee80211_local *local,
187			       struct sta_info *sta, u16 tid)
188{
189	int i;
190
191	/* prepare the filter and save it for the SW queue
192	 * matching the received HW queue */
193
194	if (!local->hw.ampdu_queues)
195		return -EPERM;
196
197	/* try to get a Qdisc from the pool */
198	for (i = local->hw.queues; i < ieee80211_num_queues(&local->hw); i++)
199		if (!test_and_set_bit(i, local->queue_pool)) {
200			ieee80211_stop_queue(local_to_hw(local), i);
201			sta->tid_to_tx_q[tid] = i;
202
203			/* IF there are already pending packets
204			 * on this tid first we need to drain them
205			 * on the previous queue
206			 * since HT is strict in order */
207#ifdef CONFIG_MAC80211_HT_DEBUG
208			if (net_ratelimit()) {
209				DECLARE_MAC_BUF(mac);
210				printk(KERN_DEBUG "allocated aggregation queue"
211					" %d tid %d addr %s pool=0x%lX\n",
212					i, tid, print_mac(mac, sta->addr),
213					local->queue_pool[0]);
214			}
215#endif /* CONFIG_MAC80211_HT_DEBUG */
216			return 0;
217		}
218
219	return -EAGAIN;
220}
221
222/**
223 * the caller needs to hold netdev_get_tx_queue(local->mdev, X)->lock
224 */
225void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
226				   struct sta_info *sta, u16 tid,
227				   u8 requeue)
228{
229	int agg_queue = sta->tid_to_tx_q[tid];
230	struct ieee80211_hw *hw = &local->hw;
231
232	/* return the qdisc to the pool */
233	clear_bit(agg_queue, local->queue_pool);
234	sta->tid_to_tx_q[tid] = ieee80211_num_queues(hw);
235
236	if (requeue) {
237		ieee80211_requeue(local, agg_queue);
238	} else {
239		struct netdev_queue *txq;
240
241		txq = netdev_get_tx_queue(local->mdev, agg_queue);
242
243		spin_lock_bh(&txq->lock);
244		qdisc_reset(txq->qdisc);
245		spin_unlock_bh(&txq->lock);
246	}
247}
248
249void ieee80211_requeue(struct ieee80211_local *local, int queue)
250{
251	struct netdev_queue *txq = netdev_get_tx_queue(local->mdev, queue);
252	struct sk_buff_head list;
253	struct Qdisc *qdisc;
254	u32 len;
255
256	rcu_read_lock_bh();
257
258	qdisc = rcu_dereference(txq->qdisc);
259	if (!qdisc || !qdisc->dequeue)
260		goto out_unlock;
261
262	skb_queue_head_init(&list);
263
264	spin_lock(&txq->lock);
265	for (len = qdisc->q.qlen; len > 0; len--) {
266		struct sk_buff *skb = qdisc->dequeue(qdisc);
267
268		if (skb)
269			__skb_queue_tail(&list, skb);
270	}
271	spin_unlock(&txq->lock);
272
273	for (len = list.qlen; len > 0; len--) {
274		struct sk_buff *skb = __skb_dequeue(&list);
275		u16 new_queue;
276
277		BUG_ON(!skb);
278		new_queue = ieee80211_select_queue(local->mdev, skb);
279		skb_set_queue_mapping(skb, new_queue);
280
281		txq = netdev_get_tx_queue(local->mdev, new_queue);
282
283		spin_lock(&txq->lock);
284
285		qdisc = rcu_dereference(txq->qdisc);
286		qdisc->enqueue(skb, qdisc);
287
288		spin_unlock(&txq->lock);
289	}
290
291out_unlock:
292	rcu_read_unlock_bh();
293}
294