wme.c revision 17741cdc264e4d768167766a252210e201c1519a 
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	return dscp >> 5;
51}
52
53
54static int wme_downgrade_ac(struct sk_buff *skb)
55{
56	switch (skb->priority) {
57	case 6:
58	case 7:
59		skb->priority = 5; /* VO -> VI */
60		return 0;
61	case 4:
62	case 5:
63		skb->priority = 3; /* VI -> BE */
64		return 0;
65	case 0:
66	case 3:
67		skb->priority = 2; /* BE -> BK */
68		return 0;
69	default:
70		return -1;
71	}
72}
73
74
75/* Indicate which queue to use.  */
76static u16 classify80211(struct sk_buff *skb, struct net_device *dev)
77{
78	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
79	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
80
81	if (!ieee80211_is_data(hdr->frame_control)) {
82		/* management frames go on AC_VO queue, but are sent
83		* without QoS control fields */
84		return 0;
85	}
86
87	if (0 /* injected */) {
88		/* use AC from radiotap */
89	}
90
91	if (!ieee80211_is_data_qos(hdr->frame_control)) {
92		skb->priority = 0; /* required for correct WPA/11i MIC */
93		return ieee802_1d_to_ac[skb->priority];
94	}
95
96	/* use the data classifier to determine what 802.1d tag the
97	 * data frame has */
98	skb->priority = classify_1d(skb);
99
100	/* in case we are a client verify acm is not set for this ac */
101	while (unlikely(local->wmm_acm & BIT(skb->priority))) {
102		if (wme_downgrade_ac(skb)) {
103			/* The old code would drop the packet in this
104			 * case.
105			 */
106			return 0;
107		}
108	}
109
110	/* look up which queue to use for frames with this 1d tag */
111	return ieee802_1d_to_ac[skb->priority];
112}
113
114u16 ieee80211_select_queue(struct net_device *dev, struct sk_buff *skb)
115{
116	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
117	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
118	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
119	struct sta_info *sta;
120	u16 queue;
121	u8 tid;
122
123	queue = classify80211(skb, dev);
124	if (unlikely(queue >= local->hw.queues))
125		queue = local->hw.queues - 1;
126
127	if (info->flags & IEEE80211_TX_CTL_REQUEUE) {
128		rcu_read_lock();
129		sta = sta_info_get(local, hdr->addr1);
130		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
131		if (sta) {
132			struct ieee80211_hw *hw = &local->hw;
133			int ampdu_queue = sta->tid_to_tx_q[tid];
134
135			if ((ampdu_queue < ieee80211_num_queues(hw)) &&
136			    test_bit(ampdu_queue, local->queue_pool)) {
137				queue = ampdu_queue;
138				info->flags |= IEEE80211_TX_CTL_AMPDU;
139			} else {
140				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
141			}
142		}
143		rcu_read_unlock();
144
145		return queue;
146	}
147
148	/* Now we know the 1d priority, fill in the QoS header if
149	 * there is one.
150	 */
151	if (ieee80211_is_data_qos(hdr->frame_control)) {
152		u8 *p = ieee80211_get_qos_ctl(hdr);
153		u8 ack_policy = 0;
154		tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
155		if (local->wifi_wme_noack_test)
156			ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
157					QOS_CONTROL_ACK_POLICY_SHIFT;
158		/* qos header is 2 bytes, second reserved */
159		*p++ = ack_policy | tid;
160		*p = 0;
161
162		rcu_read_lock();
163
164		sta = sta_info_get(local, hdr->addr1);
165		if (sta) {
166			int ampdu_queue = sta->tid_to_tx_q[tid];
167			struct ieee80211_hw *hw = &local->hw;
168
169			if ((ampdu_queue < ieee80211_num_queues(hw)) &&
170			    test_bit(ampdu_queue, local->queue_pool)) {
171				queue = ampdu_queue;
172				info->flags |= IEEE80211_TX_CTL_AMPDU;
173			} else {
174				info->flags &= ~IEEE80211_TX_CTL_AMPDU;
175			}
176		}
177
178		rcu_read_unlock();
179	}
180
181	return queue;
182}
183
184int ieee80211_ht_agg_queue_add(struct ieee80211_local *local,
185			       struct sta_info *sta, u16 tid)
186{
187	int i;
188
189	/* XXX: currently broken due to cb/requeue use */
190	return -EPERM;
191
192	/* prepare the filter and save it for the SW queue
193	 * matching the received HW queue */
194
195	if (!local->hw.ampdu_queues)
196		return -EPERM;
197
198	/* try to get a Qdisc from the pool */
199	for (i = local->hw.queues; i < ieee80211_num_queues(&local->hw); i++)
200		if (!test_and_set_bit(i, local->queue_pool)) {
201			ieee80211_stop_queue(local_to_hw(local), i);
202			sta->tid_to_tx_q[tid] = i;
203
204			/* IF there are already pending packets
205			 * on this tid first we need to drain them
206			 * on the previous queue
207			 * since HT is strict in order */
208#ifdef CONFIG_MAC80211_HT_DEBUG
209			if (net_ratelimit()) {
210				DECLARE_MAC_BUF(mac);
211				printk(KERN_DEBUG "allocated aggregation queue"
212					" %d tid %d addr %s pool=0x%lX\n",
213					i, tid, print_mac(mac, sta->sta.addr),
214					local->queue_pool[0]);
215			}
216#endif /* CONFIG_MAC80211_HT_DEBUG */
217			return 0;
218		}
219
220	return -EAGAIN;
221}
222
223/**
224 * the caller needs to hold netdev_get_tx_queue(local->mdev, X)->lock
225 */
226void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
227				   struct sta_info *sta, u16 tid,
228				   u8 requeue)
229{
230	int agg_queue = sta->tid_to_tx_q[tid];
231	struct ieee80211_hw *hw = &local->hw;
232
233	/* return the qdisc to the pool */
234	clear_bit(agg_queue, local->queue_pool);
235	sta->tid_to_tx_q[tid] = ieee80211_num_queues(hw);
236
237	if (requeue) {
238		ieee80211_requeue(local, agg_queue);
239	} else {
240		struct netdev_queue *txq;
241		spinlock_t *root_lock;
242		struct Qdisc *q;
243
244		txq = netdev_get_tx_queue(local->mdev, agg_queue);
245		q = rcu_dereference(txq->qdisc);
246		root_lock = qdisc_lock(q);
247
248		spin_lock_bh(root_lock);
249		qdisc_reset(q);
250		spin_unlock_bh(root_lock);
251	}
252}
253
254void ieee80211_requeue(struct ieee80211_local *local, int queue)
255{
256	struct netdev_queue *txq = netdev_get_tx_queue(local->mdev, queue);
257	struct sk_buff_head list;
258	spinlock_t *root_lock;
259	struct Qdisc *qdisc;
260	u32 len;
261
262	rcu_read_lock_bh();
263
264	qdisc = rcu_dereference(txq->qdisc);
265	if (!qdisc || !qdisc->dequeue)
266		goto out_unlock;
267
268	skb_queue_head_init(&list);
269
270	root_lock = qdisc_root_lock(qdisc);
271	spin_lock(root_lock);
272	for (len = qdisc->q.qlen; len > 0; len--) {
273		struct sk_buff *skb = qdisc->dequeue(qdisc);
274
275		if (skb)
276			__skb_queue_tail(&list, skb);
277	}
278	spin_unlock(root_lock);
279
280	for (len = list.qlen; len > 0; len--) {
281		struct sk_buff *skb = __skb_dequeue(&list);
282		u16 new_queue;
283
284		BUG_ON(!skb);
285		new_queue = ieee80211_select_queue(local->mdev, skb);
286		skb_set_queue_mapping(skb, new_queue);
287
288		txq = netdev_get_tx_queue(local->mdev, new_queue);
289
290
291		qdisc = rcu_dereference(txq->qdisc);
292		root_lock = qdisc_root_lock(qdisc);
293
294		spin_lock(root_lock);
295		qdisc_enqueue_root(skb, qdisc);
296		spin_unlock(root_lock);
297	}
298
299out_unlock:
300	rcu_read_unlock_bh();
301}
302