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 static u16 classify80211(struct ieee80211_local *local, struct sk_buff *skb)
  49 {
  50         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  51
  52         if (!ieee80211_is_data(hdr->frame_control)) {
  53                 /* management frames go on AC_VO queue, but are sent
  54                 * without QoS control fields */
  55                 return 0;
  56         }
  57
  58         if (0 /* injected */) {
  59                 /* use AC from radiotap */
  60         }
  61
  62         if (!ieee80211_is_data_qos(hdr->frame_control)) {
  63                 skb->priority = 0; /* required for correct WPA/11i MIC */
  64                 return ieee802_1d_to_ac[skb->priority];
  65         }
  66
  67         /* use the data classifier to determine what 802.1d tag the
  68          * data frame has */
  69         skb->priority = cfg80211_classify8021d(skb);
  70
  71         /* in case we are a client verify acm is not set for this ac */
  72         while (unlikely(local->wmm_acm & BIT(skb->priority))) {
  73                 if (wme_downgrade_ac(skb)) {
  74                         /*
  75                          * This should not really happen. The AP has marked all
  76                          * lower ACs to require admission control which is not
  77                          * a reasonable configuration. Allow the frame to be
  78                          * transmitted using AC_BK as a workaround.
  79                          */
  80                         break;
  81                 }
  82         }
  83
  84         /* look up which queue to use for frames with this 1d tag */
  85         return ieee802_1d_to_ac[skb->priority];
  86 }
  87
  88 void ieee80211_select_queue(struct ieee80211_local *local, struct sk_buff *skb)
  89 {
  90         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
  91         u16 queue;
  92         u8 tid;
  93
  94         queue = classify80211(local, skb);
  95         if (unlikely(queue >= local->hw.queues))
  96                 queue = local->hw.queues - 1;
  97
  98         /*
  99          * Now we know the 1d priority, fill in the QoS header if
 100          * there is one (and we haven't done this before).
 101          */
 102         if (ieee80211_is_data_qos(hdr->frame_control)) {
 103                 u8 *p = ieee80211_get_qos_ctl(hdr);
 104                 u8 ack_policy = 0;
 105                 tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 106                 if (unlikely(local->wifi_wme_noack_test))
 107                         ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
 108                                         QOS_CONTROL_ACK_POLICY_SHIFT;
 109                 /* qos header is 2 bytes, second reserved */
 110                 *p++ = ack_policy | tid;
 111                 *p = 0;
 112         }
 113
 114         skb_set_queue_mapping(skb, queue);
 115 }