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linux/net/mac80211/util.c

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/*
* Copyright 2002-2005, Instant802 Networks, Inc.
* Copyright 2005-2006, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007 Johannes Berg <johannes@sipsolutions.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* utilities for mac80211
*/
#include <net/mac80211.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/wireless.h>
#include <linux/bitmap.h>
#include <net/cfg80211.h>
#include "ieee80211_i.h"
#include "ieee80211_rate.h"
#include "wme.h"
/* privid for wiphys to determine whether they belong to us or not */
void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
/* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
/* Ethernet-II snap header (RFC1042 for most EtherTypes) */
const unsigned char rfc1042_header[] =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
/* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
const unsigned char bridge_tunnel_header[] =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
/* No encapsulation header if EtherType < 0x600 (=length) */
static const unsigned char eapol_header[] =
{ 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
static int rate_list_match(const int *rate_list, int rate)
{
int i;
if (!rate_list)
return 0;
for (i = 0; rate_list[i] >= 0; i++)
if (rate_list[i] == rate)
return 1;
return 0;
}
void ieee80211_prepare_rates(struct ieee80211_local *local,
struct ieee80211_hw_mode *mode)
{
int i;
for (i = 0; i < mode->num_rates; i++) {
struct ieee80211_rate *rate = &mode->rates[i];
rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
IEEE80211_RATE_BASIC);
if (local->supp_rates[mode->mode]) {
if (!rate_list_match(local->supp_rates[mode->mode],
rate->rate))
continue;
}
rate->flags |= IEEE80211_RATE_SUPPORTED;
/* Use configured basic rate set if it is available. If not,
* use defaults that are sane for most cases. */
if (local->basic_rates[mode->mode]) {
if (rate_list_match(local->basic_rates[mode->mode],
rate->rate))
rate->flags |= IEEE80211_RATE_BASIC;
} else switch (mode->mode) {
case MODE_IEEE80211A:
if (rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_IEEE80211B:
if (rate->rate == 10 || rate->rate == 20)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_ATHEROS_TURBO:
if (rate->rate == 120 || rate->rate == 240 ||
rate->rate == 480)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_IEEE80211G:
if (rate->rate == 10 || rate->rate == 20 ||
rate->rate == 55 || rate->rate == 110)
rate->flags |= IEEE80211_RATE_BASIC;
break;
}
/* Set ERP and MANDATORY flags based on phymode */
switch (mode->mode) {
case MODE_IEEE80211A:
if (rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
case MODE_IEEE80211B:
if (rate->rate == 10)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
case MODE_ATHEROS_TURBO:
break;
case MODE_IEEE80211G:
if (rate->rate == 10 || rate->rate == 20 ||
rate->rate == 55 || rate->rate == 110 ||
rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
}
if (ieee80211_is_erp_rate(mode->mode, rate->rate))
rate->flags |= IEEE80211_RATE_ERP;
}
}
u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
{
u16 fc;
if (len < 24)
return NULL;
fc = le16_to_cpu(hdr->frame_control);
switch (fc & IEEE80211_FCTL_FTYPE) {
case IEEE80211_FTYPE_DATA:
switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
case IEEE80211_FCTL_TODS:
return hdr->addr1;
case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
return NULL;
case IEEE80211_FCTL_FROMDS:
return hdr->addr2;
case 0:
return hdr->addr3;
}
break;
case IEEE80211_FTYPE_MGMT:
return hdr->addr3;
case IEEE80211_FTYPE_CTL:
if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
return hdr->addr1;
else
return NULL;
}
return NULL;
}
int ieee80211_get_hdrlen(u16 fc)
{
int hdrlen = 24;
switch (fc & IEEE80211_FCTL_FTYPE) {
case IEEE80211_FTYPE_DATA:
if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
hdrlen = 30; /* Addr4 */
/*
* The QoS Control field is two bytes and its presence is
* indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
* hdrlen if that bit is set.
* This works by masking out the bit and shifting it to
* bit position 1 so the result has the value 0 or 2.
*/
hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
>> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
break;
case IEEE80211_FTYPE_CTL:
/*
* ACK and CTS are 10 bytes, all others 16. To see how
* to get this condition consider
* subtype mask: 0b0000000011110000 (0x00F0)
* ACK subtype: 0b0000000011010000 (0x00D0)
* CTS subtype: 0b0000000011000000 (0x00C0)
* bits that matter: ^^^ (0x00E0)
* value of those: 0b0000000011000000 (0x00C0)
*/
if ((fc & 0xE0) == 0xC0)
hdrlen = 10;
else
hdrlen = 16;
break;
}
return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen);
int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
{
const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
int hdrlen;
if (unlikely(skb->len < 10))
return 0;
hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
if (unlikely(hdrlen > skb->len))
return 0;
return hdrlen;
}
EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
int ieee80211_is_eapol(const struct sk_buff *skb)
{
const struct ieee80211_hdr *hdr;
u16 fc;
int hdrlen;
if (unlikely(skb->len < 10))
return 0;
hdr = (const struct ieee80211_hdr *) skb->data;
fc = le16_to_cpu(hdr->frame_control);
if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
return 0;
hdrlen = ieee80211_get_hdrlen(fc);
if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
memcmp(skb->data + hdrlen, eapol_header,
sizeof(eapol_header)) == 0))
return 1;
return 0;
}
void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
{
struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
if (tx->u.tx.extra_frag) {
struct ieee80211_hdr *fhdr;
int i;
for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
fhdr = (struct ieee80211_hdr *)
tx->u.tx.extra_frag[i]->data;
fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
}
}
}
int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
int rate, int erp, int short_preamble)
{
int dur;
/* calculate duration (in microseconds, rounded up to next higher
* integer if it includes a fractional microsecond) to send frame of
* len bytes (does not include FCS) at the given rate. Duration will
* also include SIFS.
*
* rate is in 100 kbps, so divident is multiplied by 10 in the
* DIV_ROUND_UP() operations.
*/
if (local->hw.conf.phymode == MODE_IEEE80211A || erp ||
local->hw.conf.phymode == MODE_ATHEROS_TURBO) {
/*
* OFDM:
*
* N_DBPS = DATARATE x 4
* N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
* (16 = SIGNAL time, 6 = tail bits)
* TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
*
* T_SYM = 4 usec
* 802.11a - 17.5.2: aSIFSTime = 16 usec
* 802.11g - 19.8.4: aSIFSTime = 10 usec +
* signal ext = 6 usec
*/
/* FIX: Atheros Turbo may have different (shorter) duration? */
dur = 16; /* SIFS + signal ext */
dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
4 * rate); /* T_SYM x N_SYM */
} else {
/*
* 802.11b or 802.11g with 802.11b compatibility:
* 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
* Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
*
* 802.11 (DS): 15.3.3, 802.11b: 18.3.4
* aSIFSTime = 10 usec
* aPreambleLength = 144 usec or 72 usec with short preamble
* aPLCPHeaderLength = 48 usec or 24 usec with short preamble
*/
dur = 10; /* aSIFSTime = 10 usec */
dur += short_preamble ? (72 + 24) : (144 + 48);
dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
}
return dur;
}
/* Exported duration function for driver use */
__le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len, int rate)
{
struct ieee80211_local *local = hw_to_local(hw);
struct net_device *bdev = dev_get_by_index(if_id);
struct ieee80211_sub_if_data *sdata;
u16 dur;
int erp;
if (unlikely(!bdev))
return 0;
sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
dur = ieee80211_frame_duration(local, frame_len, rate,
erp, sdata->short_preamble);
dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_generic_frame_duration);
__le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len,
const struct ieee80211_tx_control *frame_txctl)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_rate *rate;
struct net_device *bdev = dev_get_by_index(if_id);
struct ieee80211_sub_if_data *sdata;
int short_preamble;
int erp;
u16 dur;
if (unlikely(!bdev))
return 0;
sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
short_preamble = sdata->short_preamble;
rate = frame_txctl->rts_rate;
erp = !!(rate->flags & IEEE80211_RATE_ERP);
/* CTS duration */
dur = ieee80211_frame_duration(local, 10, rate->rate,
erp, short_preamble);
/* Data frame duration */
dur += ieee80211_frame_duration(local, frame_len, rate->rate,
erp, short_preamble);
/* ACK duration */
dur += ieee80211_frame_duration(local, 10, rate->rate,
erp, short_preamble);
dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_rts_duration);
__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
size_t frame_len,
const struct ieee80211_tx_control *frame_txctl)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_rate *rate;
struct net_device *bdev = dev_get_by_index(if_id);
struct ieee80211_sub_if_data *sdata;
int short_preamble;
int erp;
u16 dur;
if (unlikely(!bdev))
return 0;
sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
short_preamble = sdata->short_preamble;
rate = frame_txctl->rts_rate;
erp = !!(rate->flags & IEEE80211_RATE_ERP);
/* Data frame duration */
dur = ieee80211_frame_duration(local, frame_len, rate->rate,
erp, short_preamble);
if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
/* ACK duration */
dur += ieee80211_frame_duration(local, 10, rate->rate,
erp, short_preamble);
}
dev_put(bdev);
return cpu_to_le16(dur);
}
EXPORT_SYMBOL(ieee80211_ctstoself_duration);
struct ieee80211_rate *
ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
{
struct ieee80211_hw_mode *mode;
int r;
list_for_each_entry(mode, &local->modes_list, list) {
if (mode->mode != phymode)
continue;
for (r = 0; r < mode->num_rates; r++) {
struct ieee80211_rate *rate = &mode->rates[r];
if (rate->val == hw_rate ||
(rate->flags & IEEE80211_RATE_PREAMBLE2 &&
rate->val2 == hw_rate))
return rate;
}
}
return NULL;
}
void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
{
struct ieee80211_local *local = hw_to_local(hw);
if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
&local->state[queue])) {
if (test_bit(IEEE80211_LINK_STATE_PENDING,
&local->state[queue]))
tasklet_schedule(&local->tx_pending_tasklet);
else
if (!ieee80211_qdisc_installed(local->mdev)) {
if (queue == 0)
netif_wake_queue(local->mdev);
} else
__netif_schedule(local->mdev);
}
}
EXPORT_SYMBOL(ieee80211_wake_queue);
void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
{
struct ieee80211_local *local = hw_to_local(hw);
if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
netif_stop_queue(local->mdev);
set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
}
EXPORT_SYMBOL(ieee80211_stop_queue);
void ieee80211_start_queues(struct ieee80211_hw *hw)
{
struct ieee80211_local *local = hw_to_local(hw);
int i;
for (i = 0; i < local->hw.queues; i++)
clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
if (!ieee80211_qdisc_installed(local->mdev))
netif_start_queue(local->mdev);
}
EXPORT_SYMBOL(ieee80211_start_queues);
void ieee80211_stop_queues(struct ieee80211_hw *hw)
{
int i;
for (i = 0; i < hw->queues; i++)
ieee80211_stop_queue(hw, i);
}
EXPORT_SYMBOL(ieee80211_stop_queues);
void ieee80211_wake_queues(struct ieee80211_hw *hw)
{
int i;
for (i = 0; i < hw->queues; i++)
ieee80211_wake_queue(hw, i);
}
EXPORT_SYMBOL(ieee80211_wake_queues);
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