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/*
* Copyright 2002-2004, Instant802 Networks, Inc.
*
* 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.
*/
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/d80211.h>
#include "ieee80211_i.h"
#include "ieee80211_rate.h"
/* Maximum number of seconds to wait for the traffic load to get below
* threshold before forcing a passive scan. */
#define MAX_SCAN_WAIT 60
/* Threshold (pkts/sec TX or RX) for delaying passive scan */
#define SCAN_TXRX_THRESHOLD 75
static void get_channel_params(struct ieee80211_local *local, int channel,
struct ieee80211_hw_mode **mode,
struct ieee80211_channel **chan)
{
struct ieee80211_hw_mode *m;
list_for_each_entry(m, &local->modes_list, list) {
*mode = m;
if (m->mode == local->hw.conf.phymode)
break;
}
local->scan.mode = m;
local->scan.chan_idx = 0;
do {
*chan = &m->channels[local->scan.chan_idx];
if ((*chan)->chan == channel)
return;
local->scan.chan_idx++;
} while (local->scan.chan_idx < m->num_channels);
*chan = NULL;
}
static void next_chan_same_mode(struct ieee80211_local *local,
struct ieee80211_hw_mode **mode,
struct ieee80211_channel **chan)
{
struct ieee80211_hw_mode *m;
int prev;
list_for_each_entry(m, &local->modes_list, list) {
*mode = m;
if (m->mode == local->hw.conf.phymode)
break;
}
local->scan.mode = m;
/* Select next channel - scan only channels marked with W_SCAN flag */
prev = local->scan.chan_idx;
do {
local->scan.chan_idx++;
if (local->scan.chan_idx >= m->num_channels)
local->scan.chan_idx = 0;
*chan = &m->channels[local->scan.chan_idx];
if ((*chan)->flag & IEEE80211_CHAN_W_SCAN)
break;
} while (local->scan.chan_idx != prev);
}
static void next_chan_all_modes(struct ieee80211_local *local,
struct ieee80211_hw_mode **mode,
struct ieee80211_channel **chan)
{
struct ieee80211_hw_mode *prev_m;
int prev;
/* Select next channel - scan only channels marked with W_SCAN flag */
prev = local->scan.chan_idx;
prev_m = local->scan.mode;
do {
*mode = local->scan.mode;
local->scan.chan_idx++;
if (local->scan.chan_idx >= (*mode)->num_channels) {
struct list_head *next;
local->scan.chan_idx = 0;
next = (*mode)->list.next;
if (next == &local->modes_list)
next = next->next;
*mode = list_entry(next,
struct ieee80211_hw_mode,
list);
local->scan.mode = *mode;
}
*chan = &(*mode)->channels[local->scan.chan_idx];
if ((*chan)->flag & IEEE80211_CHAN_W_SCAN)
break;
} while (local->scan.chan_idx != prev ||
local->scan.mode != prev_m);
}
static void ieee80211_scan_start(struct ieee80211_local *local,
struct ieee80211_scan_conf *conf)
{
struct ieee80211_hw_mode *old_mode = local->scan.mode;
int old_chan_idx = local->scan.chan_idx;
struct ieee80211_hw_mode *mode = NULL;
struct ieee80211_channel *chan = NULL;
int ret;
if (!local->ops->passive_scan) {
printk(KERN_DEBUG "%s: Scan handler called, yet the hardware "
"does not support passive scanning. Disabled.\n",
local->mdev->name);
return;
}
if ((local->scan.tries < MAX_SCAN_WAIT &&
local->scan.txrx_count > SCAN_TXRX_THRESHOLD)) {
local->scan.tries++;
/* Count TX/RX packets during one second interval and allow
* scan to start only if the number of packets is below the
* threshold. */
local->scan.txrx_count = 0;
local->scan.timer.expires = jiffies + HZ;
add_timer(&local->scan.timer);
return;
}
if (!local->scan.skb) {
printk(KERN_DEBUG "%s: Scan start called even though scan.skb "
"is not set\n", local->mdev->name);
}
if (local->scan.our_mode_only) {
if (local->scan.channel > 0) {
get_channel_params(local, local->scan.channel, &mode,
&chan);
} else
next_chan_same_mode(local, &mode, &chan);
}
else
next_chan_all_modes(local, &mode, &chan);
conf->scan_channel = chan->chan;
conf->scan_freq = chan->freq;
conf->scan_channel_val = chan->val;
conf->scan_phymode = mode->mode;
conf->scan_power_level = chan->power_level;
conf->scan_antenna_max = chan->antenna_max;
conf->scan_time = 2 * local->hw.channel_change_time +
local->scan.time; /* 10ms scan time+hardware changes */
conf->skb = local->scan.skb ?
skb_clone(local->scan.skb, GFP_ATOMIC) : NULL;
conf->tx_control = &local->scan.tx_control;
#if 0
printk(KERN_DEBUG "%s: Doing scan on mode: %d freq: %d chan: %d "
"for %d ms\n",
local->mdev->name, conf->scan_phymode, conf->scan_freq,
conf->scan_channel, conf->scan_time);
#endif
local->scan.rx_packets = 0;
local->scan.rx_beacon = 0;
local->scan.freq = chan->freq;
local->scan.in_scan = 1;
ieee80211_netif_oper(local_to_hw(local), NETIF_STOP);
ret = local->ops->passive_scan(local_to_hw(local),
IEEE80211_SCAN_START, conf);
if (ret == 0) {
long usec = local->hw.channel_change_time +
local->scan.time;
usec += 1000000L / HZ - 1;
usec /= 1000000L / HZ;
local->scan.timer.expires = jiffies + usec;
} else {
local->scan.in_scan = 0;
if (conf->skb)
dev_kfree_skb(conf->skb);
ieee80211_netif_oper(local_to_hw(local), NETIF_WAKE);
if (ret == -EAGAIN) {
local->scan.timer.expires = jiffies +
(local->scan.interval * HZ / 100);
local->scan.mode = old_mode;
local->scan.chan_idx = old_chan_idx;
} else {
printk(KERN_DEBUG "%s: Got unknown error from "
"passive_scan %d\n", local->mdev->name, ret);
local->scan.timer.expires = jiffies +
(local->scan.interval * HZ);
}
local->scan.in_scan = 0;
}
add_timer(&local->scan.timer);
}
static void ieee80211_scan_stop(struct ieee80211_local *local,
struct ieee80211_scan_conf *conf)
{
struct ieee80211_hw_mode *mode;
struct ieee80211_channel *chan;
int wait;
if (!local->ops->passive_scan)
return;
mode = local->scan.mode;
if (local->scan.chan_idx >= mode->num_channels)
local->scan.chan_idx = 0;
chan = &mode->channels[local->scan.chan_idx];
local->ops->passive_scan(local_to_hw(local), IEEE80211_SCAN_END,
conf);
#ifdef CONFIG_D80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Did scan on mode: %d freq: %d chan: %d "
"GOT: %d Beacon: %d (%d)\n",
local->mdev->name,
mode->mode, chan->freq, chan->chan,
local->scan.rx_packets, local->scan.rx_beacon,
local->scan.tries);
#endif /* CONFIG_D80211_VERBOSE_DEBUG */
local->scan.num_scans++;
local->scan.in_scan = 0;
ieee80211_netif_oper(local_to_hw(local), NETIF_WAKE);
local->scan.tries = 0;
/* Use random interval of scan.interval .. 2 * scan.interval */
wait = (local->scan.interval * HZ * ((net_random() & 127) + 128)) /
128;
local->scan.timer.expires = jiffies + wait;
add_timer(&local->scan.timer);
}
static void ieee80211_scan_handler(unsigned long ullocal)
{
struct ieee80211_local *local = (struct ieee80211_local *) ullocal;
struct ieee80211_scan_conf conf;
if (local->scan.interval == 0 && !local->scan.in_scan) {
/* Passive scanning is disabled - keep the timer always
* running to make code cleaner. */
local->scan.timer.expires = jiffies + 10 * HZ;
add_timer(&local->scan.timer);
return;
}
memset(&conf, 0, sizeof(struct ieee80211_scan_conf));
conf.running_freq = local->hw.conf.freq;
conf.running_channel = local->hw.conf.channel;
conf.running_phymode = local->hw.conf.phymode;
conf.running_channel_val = local->hw.conf.channel_val;
conf.running_power_level = local->hw.conf.power_level;
conf.running_antenna_max = local->hw.conf.antenna_max;
if (local->scan.in_scan == 0)
ieee80211_scan_start(local, &conf);
else
ieee80211_scan_stop(local, &conf);
}
void ieee80211_init_scan(struct ieee80211_local *local)
{
struct ieee80211_hdr hdr;
u16 fc;
int len = 10;
struct rate_control_extra extra;
/* Only initialize passive scanning if the hardware supports it */
if (!local->ops->passive_scan) {
local->scan.skb = NULL;
memset(&local->scan.tx_control, 0,
sizeof(local->scan.tx_control));
printk(KERN_DEBUG "%s: Does not support passive scan, "
"disabled\n", local->mdev->name);
return;
}
local->scan.interval = 0;
local->scan.our_mode_only = 1;
local->scan.time = 10000;
local->scan.timer.function = ieee80211_scan_handler;
local->scan.timer.data = (unsigned long) local;
local->scan.timer.expires = jiffies + local->scan.interval * HZ;
add_timer(&local->scan.timer);
/* Create a CTS from for broadcasting before
* the low level changes channels */
local->scan.skb = alloc_skb(len, GFP_KERNEL);
if (!local->scan.skb) {
printk(KERN_WARNING "%s: Failed to allocate CTS packet for "
"passive scan\n", local->mdev->name);
return;
}
fc = IEEE80211_FTYPE_CTL | IEEE80211_STYPE_CTS;
hdr.frame_control = cpu_to_le16(fc);
hdr.duration_id =
cpu_to_le16(2 * local->hw.channel_change_time +
local->scan.time);
memcpy(hdr.addr1, local->mdev->dev_addr, ETH_ALEN); /* DA */
hdr.seq_ctrl = 0;
memcpy(skb_put(local->scan.skb, len), &hdr, len);
memset(&local->scan.tx_control, 0, sizeof(local->scan.tx_control));
local->scan.tx_control.key_idx = HW_KEY_IDX_INVALID;
local->scan.tx_control.flags |= IEEE80211_TXCTL_DO_NOT_ENCRYPT;
memset(&extra, 0, sizeof(extra));
extra.endidx = local->num_curr_rates;
local->scan.tx_control.tx_rate =
rate_control_get_rate(local, local->mdev,
local->scan.skb, &extra)->val;
local->scan.tx_control.flags |= IEEE80211_TXCTL_NO_ACK;
}
void ieee80211_stop_scan(struct ieee80211_local *local)
{
if (local->ops->passive_scan) {
del_timer_sync(&local->scan.timer);
dev_kfree_skb(local->scan.skb);
local->scan.skb = NULL;
}
}
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