net/mac80211/wme.c

   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 int wme_downgrade_ac(struct sk_buff *skb)
  27 {
  28         switch (skb->priority) {
  29         case 6:
  30         case 7:
  31                 skb->priority = 5; /* VO -> VI */
  32                 return 0;
  33         case 4:
  34         case 5:
  35                 skb->priority = 3; /* VI -> BE */
  36                 return 0;
  37         case 0:
  38         case 3:
  39                 skb->priority = 2; /* BE -> BK */
  40                 return 0;
  41         default:
  42                 return -1;
  43         }
  44 }
  45
  46
  47 /* Indicate which queue to use. */
  48 u16 ieee80211_select_queue(struct ieee80211_sub_if_data *sdata,
  49                            struct sk_buff *skb)
  50 {
  51         struct ieee80211_local *local = sdata->local;
  52         struct sta_info *sta = NULL;
  53         u32 sta_flags = 0;
  54         const u8 *ra = NULL;
  55         bool qos = false;
  56
  57         if (local->hw.queues < 4 || skb->len < 6) {
  58                 skb->priority = 0; /* required for correct WPA/11i MIC */
  59                 return min_t(u16, local->hw.queues - 1,
  60                              ieee802_1d_to_ac[skb->priority]);
  61         }
  62
  63         rcu_read_lock();
  64         switch (sdata->vif.type) {
  65         case NL80211_IFTYPE_AP_VLAN:
  66                 rcu_read_lock();
  67                 sta = rcu_dereference(sdata->u.vlan.sta);
  68                 if (sta)
  69                         sta_flags = get_sta_flags(sta);
  70                 rcu_read_unlock();
  71                 if (sta)
  72                         break;
  73         case NL80211_IFTYPE_AP:
  74                 ra = skb->data;
  75                 break;
  76         case NL80211_IFTYPE_WDS:
  77                 ra = sdata->u.wds.remote_addr;
  78                 break;
  79 #ifdef CONFIG_MAC80211_MESH
  80         case NL80211_IFTYPE_MESH_POINT:
  81                 /*
  82                  * XXX: This is clearly broken ... but already was before,
  83                  * because ieee80211_fill_mesh_addresses() would clear A1
  84                  * except for multicast addresses.
  85                  */
  86                 break;
  87 #endif
  88         case NL80211_IFTYPE_STATION:
  89                 ra = sdata->u.mgd.bssid;
  90                 break;
  91         case NL80211_IFTYPE_ADHOC:
  92                 ra = skb->data;
  93                 break;
  94         default:
  95                 break;
  96         }
  97
  98         if (!sta && ra && !is_multicast_ether_addr(ra)) {
  99                 sta = sta_info_get(sdata, ra);
 100                 if (sta)
 101                         sta_flags = get_sta_flags(sta);
 102         }
 103
 104         if (sta_flags & WLAN_STA_WME)
 105                 qos = true;
 106
 107         rcu_read_unlock();
 108
 109         if (!qos) {
 110                 skb->priority = 0; /* required for correct WPA/11i MIC */
 111                 return ieee802_1d_to_ac[skb->priority];
 112         }
 113
 114         /* use the data classifier to determine what 802.1d tag the
 115          * data frame has */
 116         skb->priority = cfg80211_classify8021d(skb);
 117
 118         return ieee80211_downgrade_queue(local, skb);
 119 }
 120
 121 u16 ieee80211_downgrade_queue(struct ieee80211_local *local,
 122                               struct sk_buff *skb)
 123 {
 124         /* in case we are a client verify acm is not set for this ac */
 125         while (unlikely(local->wmm_acm & BIT(skb->priority))) {
 126                 if (wme_downgrade_ac(skb)) {
 127                         /*
 128                          * This should not really happen. The AP has marked all
 129                          * lower ACs to require admission control which is not
 130                          * a reasonable configuration. Allow the frame to be
 131                          * transmitted using AC_BK as a workaround.
 132                          */
 133                         break;
 134                 }
 135         }
 136
 137         /* look up which queue to use for frames with this 1d tag */
 138         return ieee802_1d_to_ac[skb->priority];
 139 }
 140
 141 void ieee80211_set_qos_hdr(struct ieee80211_local *local, struct sk_buff *skb)
 142 {
 143         struct ieee80211_hdr *hdr = (void *)skb->data;
 144
 145         /* Fill in the QoS header if there is one. */
 146         if (ieee80211_is_data_qos(hdr->frame_control)) {
 147                 u8 *p = ieee80211_get_qos_ctl(hdr);
 148                 u8 ack_policy = 0, tid;
 149
 150                 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 151
 152                 if (unlikely(local->wifi_wme_noack_test))
 153                         ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
 154                                         QOS_CONTROL_ACK_POLICY_SHIFT;
 155                 /* qos header is 2 bytes, second reserved */
 156                 *p++ = ack_policy | tid;
 157                 *p = 0;
 158         }
 159 }