LXR linux/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 */
  24const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };
  25
  26static 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.  */
  48static 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
  88void 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}
 116