linux/net/mac80211/wme.c
<<
>>
Prefs
   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 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 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                        /*
 103                         * This should not really happen. The AP has marked all
 104                         * lower ACs to require admission control which is not
 105                         * a reasonable configuration. Allow the frame to be
 106                         * transmitted using AC_BK as a workaround.
 107                         */
 108                        break;
 109                }
 110        }
 111
 112        /* look up which queue to use for frames with this 1d tag */
 113        return ieee802_1d_to_ac[skb->priority];
 114}
 115
 116u16 ieee80211_select_queue(struct net_device *dev, struct sk_buff *skb)
 117{
 118        struct ieee80211_master_priv *mpriv = netdev_priv(dev);
 119        struct ieee80211_local *local = mpriv->local;
 120        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 121        u16 queue;
 122        u8 tid;
 123
 124        queue = classify80211(local, skb);
 125        if (unlikely(queue >= local->hw.queues))
 126                queue = local->hw.queues - 1;
 127
 128        /*
 129         * Now we know the 1d priority, fill in the QoS header if
 130         * there is one (and we haven't done this before).
 131         */
 132        if (!skb->requeue && ieee80211_is_data_qos(hdr->frame_control)) {
 133                u8 *p = ieee80211_get_qos_ctl(hdr);
 134                u8 ack_policy = 0;
 135                tid = skb->priority & IEEE80211_QOS_CTL_TAG1D_MASK;
 136                if (local->wifi_wme_noack_test)
 137                        ack_policy |= QOS_CONTROL_ACK_POLICY_NOACK <<
 138                                        QOS_CONTROL_ACK_POLICY_SHIFT;
 139                /* qos header is 2 bytes, second reserved */
 140                *p++ = ack_policy | tid;
 141                *p = 0;
 142        }
 143
 144        return queue;
 145}
 146