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   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  */
  24 const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };
  25
  26 static 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.  */
  29 static 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 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
  54 static 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.  */
  76 static u16 classify80211(struct ieee80211_local *local, struct sk_buff *skb)
  77 {
  78         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  79
  80         if (!ieee80211_is_data(hdr->frame_control)) {
  81                 /* management frames go on AC_VO queue, but are sent
  82                 * without QoS control fields */
  83                 return 0;
  84         }
  85
  86         if (0 /* injected */) {
  87                 /* use AC from radiotap */
  88         }
  89
  90         if (!ieee80211_is_data_qos(hdr->frame_control)) {
  91                 skb->priority = 0; /* required for correct WPA/11i MIC */
  92                 return ieee802_1d_to_ac[skb->priority];
  93         }
  94
  95         /* use the data classifier to determine what 802.1d tag the
  96          * data frame has */
  97         skb->priority = classify_1d(skb);
  98
  99         /* in case we are a client verify acm is not set for this ac */
 100         while (unlikely(local->wmm_acm & BIT(skb->priority))) {
 101                 if (wme_downgrade_ac(skb)) {
 102                         /* The old code would drop the packet in this
 103                          * case.
 104                          */
 105                         return 0;
 106                 }
 107         }
 108
 109         /* look up which queue to use for frames with this 1d tag */
 110         return ieee802_1d_to_ac[skb->priority];
 111 }
 112
 113 u16 ieee80211_select_queue(struct net_device *dev, struct sk_buff *skb)
 114 {
 115         struct ieee80211_master_priv *mpriv = netdev_priv(dev);
 116         struct ieee80211_local *local = mpriv->local;
 117         struct ieee80211_hw *hw = &local->hw;
 118         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 119         struct sta_info *sta;
 120         u16 queue;
 121         u8 tid;
 122
 123         queue = classify80211(local, skb);
 124         if (unlikely(queue >= local->hw.queues))
 125                 queue = local->hw.queues - 1;
 126
 127         if (skb->requeue) {
 128                 if (!hw->ampdu_queues)
 129                         return queue;
 130
 131                 rcu_read_lock();
 132                 sta = sta_info_get(local, hdr->addr1);
 133                 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 134                 if (sta) {
 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                 }
 141                 rcu_read_unlock();
 142
 143                 return queue;
 144         }
 145
 146         /* Now we know the 1d priority, fill in the QoS header if
 147          * there is one.
 148          */
 149         if (ieee80211_is_data_qos(hdr->frame_control)) {
 150                 u8 *p = ieee80211_get_qos_ctl(hdr);
 151                 u8 ack_policy = 0;
 152                 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 153                 if (local->wifi_wme_noack_test)
 154                         ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
 155                                         QOS_CONTROL_ACK_POLICY_SHIFT;
 156                 /* qos header is 2 bytes, second reserved */
 157                 *p++ = ack_policy | tid;
 158                 *p = 0;
 159
 160                 if (!hw->ampdu_queues)
 161                         return queue;
 162
 163                 rcu_read_lock();
 164
 165                 sta = sta_info_get(local, hdr->addr1);
 166                 if (sta) {
 167                         int ampdu_queue = sta->tid_to_tx_q[tid];
 168
 169                         if ((ampdu_queue < ieee80211_num_queues(hw)) &&
 170                             test_bit(ampdu_queue, local->queue_pool))
 171                                 queue = ampdu_queue;
 172                 }
 173
 174                 rcu_read_unlock();
 175         }
 176
 177         return queue;
 178 }
 179
 180 int ieee80211_ht_agg_queue_add(struct ieee80211_local *local,
 181                                struct sta_info *sta, u16 tid)
 182 {
 183         int i;
 184
 185         /* XXX: currently broken due to cb/requeue use */
 186         return -EPERM;
 187
 188         /* prepare the filter and save it for the SW queue
 189          * matching the received HW queue */
 190
 191         if (!local->hw.ampdu_queues)
 192                 return -EPERM;
 193
 194         /* try to get a Qdisc from the pool */
 195         for (i = local->hw.queues; i < ieee80211_num_queues(&local->hw); i++)
 196                 if (!test_and_set_bit(i, local->queue_pool)) {
 197                         ieee80211_stop_queue(local_to_hw(local), i);
 198                         sta->tid_to_tx_q[tid] = i;
 199
 200                         /* IF there are already pending packets
 201                          * on this tid first we need to drain them
 202                          * on the previous queue
 203                          * since HT is strict in order */
 204 #ifdef CONFIG_MAC80211_HT_DEBUG
 205                         if (net_ratelimit())
 206                                 printk(KERN_DEBUG "allocated aggregation queue"
 207                                         " %d tid %d addr %pM pool=0x%lX\n",
 208                                         i, tid, sta->sta.addr,
 209                                         local->queue_pool[0]);
 210 #endif /* CONFIG_MAC80211_HT_DEBUG */
 211                         return 0;
 212                 }
 213
 214         return -EAGAIN;
 215 }
 216
 217 /**
 218  * the caller needs to hold netdev_get_tx_queue(local->mdev, X)->lock
 219  */
 220 void ieee80211_ht_agg_queue_remove(struct ieee80211_local *local,
 221                                    struct sta_info *sta, u16 tid,
 222                                    u8 requeue)
 223 {
 224         int agg_queue = sta->tid_to_tx_q[tid];
 225         struct ieee80211_hw *hw = &local->hw;
 226
 227         /* return the qdisc to the pool */
 228         clear_bit(agg_queue, local->queue_pool);
 229         sta->tid_to_tx_q[tid] = ieee80211_num_queues(hw);
 230
 231         if (requeue) {
 232                 ieee80211_requeue(local, agg_queue);
 233         } else {
 234                 struct netdev_queue *txq;
 235                 spinlock_t *root_lock;
 236                 struct Qdisc *q;
 237
 238                 txq = netdev_get_tx_queue(local->mdev, agg_queue);
 239                 q = rcu_dereference(txq->qdisc);
 240                 root_lock = qdisc_lock(q);
 241
 242                 spin_lock_bh(root_lock);
 243                 qdisc_reset(q);
 244                 spin_unlock_bh(root_lock);
 245         }
 246 }
 247
 248 void ieee80211_requeue(struct ieee80211_local *local, int queue)
 249 {
 250         struct netdev_queue *txq = netdev_get_tx_queue(local->mdev, queue);
 251         struct sk_buff_head list;
 252         spinlock_t *root_lock;
 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         root_lock = qdisc_root_lock(qdisc);
 265         spin_lock(root_lock);
 266         for (len = qdisc->q.qlen; len > 0; len--) {
 267                 struct sk_buff *skb = qdisc->dequeue(qdisc);
 268
 269                 if (skb)
 270                         __skb_queue_tail(&list, skb);
 271         }
 272         spin_unlock(root_lock);
 273
 274         for (len = list.qlen; len > 0; len--) {
 275                 struct sk_buff *skb = __skb_dequeue(&list);
 276                 u16 new_queue;
 277
 278                 BUG_ON(!skb);
 279                 new_queue = ieee80211_select_queue(local->mdev, skb);
 280                 skb_set_queue_mapping(skb, new_queue);
 281
 282                 txq = netdev_get_tx_queue(local->mdev, new_queue);
 283
 284
 285                 qdisc = rcu_dereference(txq->qdisc);
 286                 root_lock = qdisc_root_lock(qdisc);
 287
 288                 spin_lock(root_lock);
 289                 qdisc_enqueue_root(skb, qdisc);
 290                 spin_unlock(root_lock);
 291         }
 292
 293 out_unlock:
 294         rcu_read_unlock_bh();
 295 }