1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
|
/*
* 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/config.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/ieee80211.h>
#include "ieee80211_i.h"
#include "rate_control.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_modes **mode,
struct ieee80211_channel **chan)
{
int m;
for (m = 0; m < local->hw->num_modes; m++) {
*mode = &local->hw->modes[m];
if ((*mode)->mode == local->conf.phymode)
break;
}
local->scan.mode_idx = m;
local->scan.chan_idx = 0;
do {
*chan = &(*mode)->channels[local->scan.chan_idx];
if ((*chan)->chan == channel) {
return;
}
local->scan.chan_idx++;
} while (local->scan.chan_idx < (*mode)->num_channels);
*chan = NULL;
}
static void next_chan_same_mode(struct ieee80211_local *local,
struct ieee80211_hw_modes **mode,
struct ieee80211_channel **chan)
{
int m, prev;
for (m = 0; m < local->hw->num_modes; m++) {
*mode = &local->hw->modes[m];
if ((*mode)->mode == local->conf.phymode)
break;
}
local->scan.mode_idx = 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 >= (*mode)->num_channels)
local->scan.chan_idx = 0;
*chan = &(*mode)->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_modes **mode,
struct ieee80211_channel **chan)
{
int prev, prev_m;
if (local->scan.mode_idx >= local->hw->num_modes) {
local->scan.mode_idx = 0;
local->scan.chan_idx = 0;
}
/* Select next channel - scan only channels marked with W_SCAN flag */
prev = local->scan.chan_idx;
prev_m = local->scan.mode_idx;
do {
*mode = &local->hw->modes[local->scan.mode_idx];
local->scan.chan_idx++;
if (local->scan.chan_idx >= (*mode)->num_channels) {
local->scan.chan_idx = 0;
local->scan.mode_idx++;
if (local->scan.mode_idx >= local->hw->num_modes)
local->scan.mode_idx = 0;
*mode = &local->hw->modes[local->scan.mode_idx];
}
*chan = &(*mode)->channels[local->scan.chan_idx];
if ((*chan)->flag & IEEE80211_CHAN_W_SCAN)
break;
} while (local->scan.chan_idx != prev ||
local->scan.mode_idx != prev_m);
}
static void ieee80211_scan_start(struct net_device *dev,
struct ieee80211_scan_conf *conf)
{
struct ieee80211_local *local = dev->priv;
int old_mode_idx = local->scan.mode_idx;
int old_chan_idx = local->scan.chan_idx;
struct ieee80211_hw_modes *mode = NULL;
struct ieee80211_channel *chan = NULL;
int ret;
if (local->hw->passive_scan == 0) {
printk(KERN_DEBUG "%s: Scan handler called, yet the hardware "
"does not support passive scanning. Disabled.\n",
dev->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 == NULL) {
printk(KERN_DEBUG "%s: Scan start called even though scan.skb "
"is not set\n", dev->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",
dev->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(dev, NETIF_STOP);
ret = local->hw->passive_scan(dev, 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(dev, NETIF_WAKE);
if (ret == -EAGAIN) {
local->scan.timer.expires = jiffies +
(local->scan.interval * HZ / 100);
local->scan.mode_idx = old_mode_idx;
local->scan.chan_idx = old_chan_idx;
} else {
printk(KERN_DEBUG "%s: Got unknown error from "
"passive_scan %d\n", dev->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 net_device *dev,
struct ieee80211_scan_conf *conf)
{
struct ieee80211_local *local = dev->priv;
struct ieee80211_hw_modes *mode;
struct ieee80211_channel *chan;
int wait;
if (local->hw->passive_scan == NULL)
return;
if (local->scan.mode_idx >= local->hw->num_modes) {
local->scan.mode_idx = 0;
local->scan.chan_idx = 0;
}
mode = &local->hw->modes[local->scan.mode_idx];
if (local->scan.chan_idx >= mode->num_channels) {
local->scan.chan_idx = 0;
}
chan = &mode->channels[local->scan.chan_idx];
local->hw->passive_scan(dev, IEEE80211_SCAN_END, conf);
#ifdef CONFIG_IEEE80211_VERBOSE_DEBUG
printk(KERN_DEBUG "%s: Did scan on mode: %d freq: %d chan: %d "
"GOT: %d Beacon: %d (%d)\n",
dev->name,
mode->mode, chan->freq, chan->chan,
local->scan.rx_packets, local->scan.rx_beacon,
local->scan.tries);
#endif /* CONFIG_IEEE80211_VERBOSE_DEBUG */
local->scan.num_scans++;
local->scan.in_scan = 0;
ieee80211_netif_oper(dev, 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 uldev)
{
struct net_device *dev = (struct net_device *) uldev;
struct ieee80211_local *local = dev->priv;
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->conf.freq;
conf.running_channel = local->conf.channel;
conf.running_phymode = local->conf.phymode;
conf.running_channel_val = local->conf.channel_val;
conf.running_power_level = local->conf.power_level;
conf.running_antenna_max = local->conf.antenna_max;
if (local->scan.in_scan == 0)
ieee80211_scan_start(dev, &conf);
else
ieee80211_scan_stop(dev, &conf);
}
void ieee80211_init_scan(struct net_device *dev)
{
struct ieee80211_local *local = dev->priv;
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->hw->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", dev->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) dev;
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 == NULL) {
printk(KERN_WARNING "%s: Failed to allocate CTS packet for "
"passive scan\n", dev->name);
return;
}
fc = (WLAN_FC_TYPE_CTRL << 2) | (WLAN_FC_STYPE_CTS << 4);
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, dev->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.do_not_encrypt = 1;
memset(&extra, 0, sizeof(extra));
extra.endidx = local->num_curr_rates;
local->scan.tx_control.tx_rate =
rate_control_get_rate(dev, local->scan.skb, &extra)->val;
local->scan.tx_control.no_ack = 1;
}
void ieee80211_stop_scan(struct net_device *dev)
{
struct ieee80211_local *local = dev->priv;
if (local->hw->passive_scan != 0) {
del_timer_sync(&local->scan.timer);
dev_kfree_skb(local->scan.skb);
local->scan.skb = NULL;
}
}
|
