linux/net/mac80211/scan.c

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/*
* BSS client mode implementation
* Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
* Copyright 2004, Instant802 Networks, Inc.
* Copyright 2005, Devicescape Software, Inc.
* Copyright 2006-2007 Jiri Benc <jbenc@suse.cz>
* Copyright 2007, Michael Wu <flamingice@sourmilk.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.
*/
#include <linux/wireless.h>
#include <linux/if_arp.h>
#include <net/mac80211.h>
#include <net/iw_handler.h>
#include "ieee80211_i.h"
#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
ieee80211_rx_result
ieee80211_sta_rx_scan(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
struct ieee80211_rx_status *rx_status)
{
struct ieee80211_mgmt *mgmt;
struct ieee80211_sta_bss *bss;
u8 *elements;
struct ieee80211_channel *channel;
size_t baselen;
int freq;
__le16 fc;
bool presp, beacon = false;
struct ieee802_11_elems elems;
if (skb->len < 2)
return RX_DROP_UNUSABLE;
mgmt = (struct ieee80211_mgmt *) skb->data;
fc = mgmt->frame_control;
if (ieee80211_is_ctl(fc))
return RX_CONTINUE;
if (skb->len < 24)
return RX_DROP_MONITOR;
presp = ieee80211_is_probe_resp(fc);
if (presp) {
/* ignore ProbeResp to foreign address */
if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
return RX_DROP_MONITOR;
presp = true;
elements = mgmt->u.probe_resp.variable;
baselen = offsetof(struct ieee80211_mgmt, u.probe_resp.variable);
} else {
beacon = ieee80211_is_beacon(fc);
baselen = offsetof(struct ieee80211_mgmt, u.beacon.variable);
elements = mgmt->u.beacon.variable;
}
if (!presp && !beacon)
return RX_CONTINUE;
if (baselen > skb->len)
return RX_DROP_MONITOR;
ieee802_11_parse_elems(elements, skb->len - baselen, &elems);
if (elems.ds_params && elems.ds_params_len == 1)
freq = ieee80211_channel_to_frequency(elems.ds_params[0]);
else
freq = rx_status->freq;
channel = ieee80211_get_channel(sdata->local->hw.wiphy, freq);
if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
return RX_DROP_MONITOR;
bss = ieee80211_bss_info_update(sdata->local, rx_status,
mgmt, skb->len, &elems,
freq, beacon);
ieee80211_rx_bss_put(sdata->local, bss);
dev_kfree_skb(skb);
return RX_QUEUED;
}
static void ieee80211_send_nullfunc(struct ieee80211_local *local,
struct ieee80211_sub_if_data *sdata,
int powersave)
{
struct sk_buff *skb;
struct ieee80211_hdr *nullfunc;
__le16 fc;
skb = dev_alloc_skb(local->hw.extra_tx_headroom + 24);
if (!skb) {
printk(KERN_DEBUG "%s: failed to allocate buffer for nullfunc "
"frame\n", sdata->dev->name);
return;
}
skb_reserve(skb, local->hw.extra_tx_headroom);
nullfunc = (struct ieee80211_hdr *) skb_put(skb, 24);
memset(nullfunc, 0, 24);
fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_NULLFUNC |
IEEE80211_FCTL_TODS);
if (powersave)
fc |= cpu_to_le16(IEEE80211_FCTL_PM);
nullfunc->frame_control = fc;
memcpy(nullfunc->addr1, sdata->u.sta.bssid, ETH_ALEN);
memcpy(nullfunc->addr2, sdata->dev->dev_addr, ETH_ALEN);
memcpy(nullfunc->addr3, sdata->u.sta.bssid, ETH_ALEN);
ieee80211_sta_tx(sdata, skb, 0);
}
static void ieee80211_restart_sta_timer(struct ieee80211_sub_if_data *sdata)
{
if (sdata->vif.type == IEEE80211_IF_TYPE_STA ||
ieee80211_vif_is_mesh(&sdata->vif))
ieee80211_sta_timer((unsigned long)sdata);
}
void ieee80211_scan_completed(struct ieee80211_hw *hw)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
union iwreq_data wrqu;
local->last_scan_completed = jiffies;
memset(&wrqu, 0, sizeof(wrqu));
wireless_send_event(local->scan_sdata->dev, SIOCGIWSCAN, &wrqu, NULL);
if (local->sta_hw_scanning) {
local->sta_hw_scanning = 0;
if (ieee80211_hw_config(local))
printk(KERN_DEBUG "%s: failed to restore operational "
"channel after scan\n", wiphy_name(local->hw.wiphy));
/* Restart STA timer for HW scan case */
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list)
ieee80211_restart_sta_timer(sdata);
rcu_read_unlock();
goto done;
}
local->sta_sw_scanning = 0;
if (ieee80211_hw_config(local))
printk(KERN_DEBUG "%s: failed to restore operational "
"channel after scan\n", wiphy_name(local->hw.wiphy));
netif_tx_lock_bh(local->mdev);
netif_addr_lock(local->mdev);
local->filter_flags &= ~FIF_BCN_PRBRESP_PROMISC;
local->ops->configure_filter(local_to_hw(local),
FIF_BCN_PRBRESP_PROMISC,
&local->filter_flags,
local->mdev->mc_count,
local->mdev->mc_list);
netif_addr_unlock(local->mdev);
netif_tx_unlock_bh(local->mdev);
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
/* Tell AP we're back */
if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
ieee80211_send_nullfunc(local, sdata, 0);
netif_tx_wake_all_queues(sdata->dev);
}
} else
netif_tx_wake_all_queues(sdata->dev);
ieee80211_restart_sta_timer(sdata);
}
rcu_read_unlock();
done:
ieee80211_mlme_notify_scan_completed(local);
}
EXPORT_SYMBOL(ieee80211_scan_completed);
void ieee80211_sta_scan_work(struct work_struct *work)
{
struct ieee80211_local *local =
container_of(work, struct ieee80211_local, scan_work.work);
struct ieee80211_sub_if_data *sdata = local->scan_sdata;
struct ieee80211_supported_band *sband;
struct ieee80211_channel *chan;
int skip;
unsigned long next_delay = 0;
if (!local->sta_sw_scanning)
return;
switch (local->scan_state) {
case SCAN_SET_CHANNEL:
/*
* Get current scan band. scan_band may be IEEE80211_NUM_BANDS
* after we successfully scanned the last channel of the last
* band (and the last band is supported by the hw)
*/
if (local->scan_band < IEEE80211_NUM_BANDS)
sband = local->hw.wiphy->bands[local->scan_band];
else
sband = NULL;
/*
* If we are at an unsupported band and have more bands
* left to scan, advance to the next supported one.
*/
while (!sband && local->scan_band < IEEE80211_NUM_BANDS - 1) {
local->scan_band++;
sband = local->hw.wiphy->bands[local->scan_band];
local->scan_channel_idx = 0;
}
/* if no more bands/channels left, complete scan */
if (!sband || local->scan_channel_idx >= sband->n_channels) {
ieee80211_scan_completed(local_to_hw(local));
return;
}
skip = 0;
chan = &sband->channels[local->scan_channel_idx];
if (chan->flags & IEEE80211_CHAN_DISABLED ||
(sdata->vif.type == IEEE80211_IF_TYPE_IBSS &&
chan->flags & IEEE80211_CHAN_NO_IBSS))
skip = 1;
if (!skip) {
local->scan_channel = chan;
if (ieee80211_hw_config(local)) {
printk(KERN_DEBUG "%s: failed to set freq to "
"%d MHz for scan\n", wiphy_name(local->hw.wiphy),
chan->center_freq);
skip = 1;
}
}
/* advance state machine to next channel/band */
local->scan_channel_idx++;
if (local->scan_channel_idx >= sband->n_channels) {
/*
* scan_band may end up == IEEE80211_NUM_BANDS, but
* we'll catch that case above and complete the scan
* if that is the case.
*/
local->scan_band++;
local->scan_channel_idx = 0;
}
if (skip)
break;
next_delay = IEEE80211_PROBE_DELAY +
usecs_to_jiffies(local->hw.channel_change_time);
local->scan_state = SCAN_SEND_PROBE;
break;
case SCAN_SEND_PROBE:
next_delay = IEEE80211_PASSIVE_CHANNEL_TIME;
local->scan_state = SCAN_SET_CHANNEL;
if (local->scan_channel->flags & IEEE80211_CHAN_PASSIVE_SCAN)
break;
ieee80211_send_probe_req(sdata, NULL, local->scan_ssid,
local->scan_ssid_len);
next_delay = IEEE80211_CHANNEL_TIME;
break;
}
if (local->sta_sw_scanning)
queue_delayed_work(local->hw.workqueue, &local->scan_work,
next_delay);
}
int ieee80211_sta_start_scan(struct ieee80211_sub_if_data *scan_sdata,
u8 *ssid, size_t ssid_len)
{
struct ieee80211_local *local = scan_sdata->local;
struct ieee80211_sub_if_data *sdata;
if (ssid_len > IEEE80211_MAX_SSID_LEN)
return -EINVAL;
/* MLME-SCAN.request (page 118) page 144 (11.1.3.1)
* BSSType: INFRASTRUCTURE, INDEPENDENT, ANY_BSS
* BSSID: MACAddress
* SSID
* ScanType: ACTIVE, PASSIVE
* ProbeDelay: delay (in microseconds) to be used prior to transmitting
* a Probe frame during active scanning
* ChannelList
* MinChannelTime (>= ProbeDelay), in TU
* MaxChannelTime: (>= MinChannelTime), in TU
*/
/* MLME-SCAN.confirm
* BSSDescriptionSet
* ResultCode: SUCCESS, INVALID_PARAMETERS
*/
if (local->sta_sw_scanning || local->sta_hw_scanning) {
if (local->scan_sdata == scan_sdata)
return 0;
return -EBUSY;
}
if (local->ops->hw_scan) {
int rc = local->ops->hw_scan(local_to_hw(local),
ssid, ssid_len);
if (!rc) {
local->sta_hw_scanning = 1;
local->scan_sdata = scan_sdata;
}
return rc;
}
local->sta_sw_scanning = 1;
rcu_read_lock();
list_for_each_entry_rcu(sdata, &local->interfaces, list) {
if (sdata->vif.type == IEEE80211_IF_TYPE_STA) {
if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) {
netif_tx_stop_all_queues(sdata->dev);
ieee80211_send_nullfunc(local, sdata, 1);
}
} else
netif_tx_stop_all_queues(sdata->dev);
}
rcu_read_unlock();
if (ssid) {
local->scan_ssid_len = ssid_len;
memcpy(local->scan_ssid, ssid, ssid_len);
} else
local->scan_ssid_len = 0;
local->scan_state = SCAN_SET_CHANNEL;
local->scan_channel_idx = 0;
local->scan_band = IEEE80211_BAND_2GHZ;
local->scan_sdata = scan_sdata;
netif_addr_lock_bh(local->mdev);
local->filter_flags |= FIF_BCN_PRBRESP_PROMISC;
local->ops->configure_filter(local_to_hw(local),
FIF_BCN_PRBRESP_PROMISC,
&local->filter_flags,
local->mdev->mc_count,
local->mdev->mc_list);
netif_addr_unlock_bh(local->mdev);
/* TODO: start scan as soon as all nullfunc frames are ACKed */
queue_delayed_work(local->hw.workqueue, &local->scan_work,
IEEE80211_CHANNEL_TIME);
return 0;
}
int ieee80211_sta_req_scan(struct ieee80211_sub_if_data *sdata, u8 *ssid, size_t ssid_len)
{
struct ieee80211_if_sta *ifsta = &sdata->u.sta;
struct ieee80211_local *local = sdata->local;
if (sdata->vif.type != IEEE80211_IF_TYPE_STA)
return ieee80211_sta_start_scan(sdata, ssid, ssid_len);
if (local->sta_sw_scanning || local->sta_hw_scanning) {
if (local->scan_sdata == sdata)
return 0;
return -EBUSY;
}
ifsta->scan_ssid_len = ssid_len;
if (ssid_len)
memcpy(ifsta->scan_ssid, ssid, ssid_len);
set_bit(IEEE80211_STA_REQ_SCAN, &ifsta->request);
queue_work(local->hw.workqueue, &ifsta->work);
return 0;
}
static void ieee80211_sta_add_scan_ies(struct iw_request_info *info,
struct ieee80211_sta_bss *bss,
char **current_ev, char *end_buf)
{
u8 *pos, *end, *next;
struct iw_event iwe;
if (bss == NULL || bss->ies == NULL)
return;
/*
* If needed, fragment the IEs buffer (at IE boundaries) into short
* enough fragments to fit into IW_GENERIC_IE_MAX octet messages.
*/
pos = bss->ies;
end = pos + bss->ies_len;
while (end - pos > IW_GENERIC_IE_MAX) {
next = pos + 2 + pos[1];
while (next + 2 + next[1] - pos < IW_GENERIC_IE_MAX)
next = next + 2 + next[1];
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVGENIE;
iwe.u.data.length = next - pos;
*current_ev = iwe_stream_add_point(info, *current_ev,
end_buf, &iwe, pos);
pos = next;
}
if (end > pos) {
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVGENIE;
iwe.u.data.length = end - pos;
*current_ev = iwe_stream_add_point(info, *current_ev,
end_buf, &iwe, pos);
}
}
static char *
ieee80211_sta_scan_result(struct ieee80211_local *local,
struct iw_request_info *info,
struct ieee80211_sta_bss *bss,
char *current_ev, char *end_buf)
{
struct iw_event iwe;
char *buf;
if (time_after(jiffies,
bss->last_update + IEEE80211_SCAN_RESULT_EXPIRE))
return current_ev;
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWAP;
iwe.u.ap_addr.sa_family = ARPHRD_ETHER;
memcpy(iwe.u.ap_addr.sa_data, bss->bssid, ETH_ALEN);
current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
IW_EV_ADDR_LEN);
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWESSID;
if (bss_mesh_cfg(bss)) {
iwe.u.data.length = bss_mesh_id_len(bss);
iwe.u.data.flags = 1;
current_ev = iwe_stream_add_point(info, current_ev, end_buf,
&iwe, bss_mesh_id(bss));
} else {
iwe.u.data.length = bss->ssid_len;
iwe.u.data.flags = 1;
current_ev = iwe_stream_add_point(info, current_ev, end_buf,
&iwe, bss->ssid);
}
if (bss->capability & (WLAN_CAPABILITY_ESS | WLAN_CAPABILITY_IBSS)
|| bss_mesh_cfg(bss)) {
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWMODE;
if (bss_mesh_cfg(bss))
iwe.u.mode = IW_MODE_MESH;
else if (bss->capability & WLAN_CAPABILITY_ESS)
iwe.u.mode = IW_MODE_MASTER;
else
iwe.u.mode = IW_MODE_ADHOC;
current_ev = iwe_stream_add_event(info, current_ev, end_buf,
&iwe, IW_EV_UINT_LEN);
}
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWFREQ;
iwe.u.freq.m = ieee80211_frequency_to_channel(bss->freq);
iwe.u.freq.e = 0;
current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
IW_EV_FREQ_LEN);
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWFREQ;
iwe.u.freq.m = bss->freq;
iwe.u.freq.e = 6;
current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
IW_EV_FREQ_LEN);
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVQUAL;
iwe.u.qual.qual = bss->qual;
iwe.u.qual.level = bss->signal;
iwe.u.qual.noise = bss->noise;
iwe.u.qual.updated = local->wstats_flags;
current_ev = iwe_stream_add_event(info, current_ev, end_buf, &iwe,
IW_EV_QUAL_LEN);
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWENCODE;
if (bss->capability & WLAN_CAPABILITY_PRIVACY)
iwe.u.data.flags = IW_ENCODE_ENABLED | IW_ENCODE_NOKEY;
else
iwe.u.data.flags = IW_ENCODE_DISABLED;
iwe.u.data.length = 0;
current_ev = iwe_stream_add_point(info, current_ev, end_buf,
&iwe, "");
ieee80211_sta_add_scan_ies(info, bss, &current_ev, end_buf);
if (bss->supp_rates_len > 0) {
/* display all supported rates in readable format */
char *p = current_ev + iwe_stream_lcp_len(info);
int i;
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = SIOCGIWRATE;
/* Those two flags are ignored... */
iwe.u.bitrate.fixed = iwe.u.bitrate.disabled = 0;
for (i = 0; i < bss->supp_rates_len; i++) {
iwe.u.bitrate.value = ((bss->supp_rates[i] &
0x7f) * 500000);
p = iwe_stream_add_value(info, current_ev, p,
end_buf, &iwe, IW_EV_PARAM_LEN);
}
current_ev = p;
}
buf = kmalloc(30, GFP_ATOMIC);
if (buf) {
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVCUSTOM;
sprintf(buf, "tsf=%016llx", (unsigned long long)(bss->timestamp));
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev, end_buf,
&iwe, buf);
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVCUSTOM;
sprintf(buf, " Last beacon: %dms ago",
jiffies_to_msecs(jiffies - bss->last_update));
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf, &iwe, buf);
kfree(buf);
}
if (bss_mesh_cfg(bss)) {
u8 *cfg = bss_mesh_cfg(bss);
buf = kmalloc(50, GFP_ATOMIC);
if (buf) {
memset(&iwe, 0, sizeof(iwe));
iwe.cmd = IWEVCUSTOM;
sprintf(buf, "Mesh network (version %d)", cfg[0]);
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf,
&iwe, buf);
sprintf(buf, "Path Selection Protocol ID: "
"0x%02X%02X%02X%02X", cfg[1], cfg[2], cfg[3],
cfg[4]);
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf,
&iwe, buf);
sprintf(buf, "Path Selection Metric ID: "
"0x%02X%02X%02X%02X", cfg[5], cfg[6], cfg[7],
cfg[8]);
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf,
&iwe, buf);
sprintf(buf, "Congestion Control Mode ID: "
"0x%02X%02X%02X%02X", cfg[9], cfg[10],
cfg[11], cfg[12]);
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf,
&iwe, buf);
sprintf(buf, "Channel Precedence: "
"0x%02X%02X%02X%02X", cfg[13], cfg[14],
cfg[15], cfg[16]);
iwe.u.data.length = strlen(buf);
current_ev = iwe_stream_add_point(info, current_ev,
end_buf,
&iwe, buf);
kfree(buf);
}
}
return current_ev;
}
int ieee80211_sta_scan_results(struct ieee80211_local *local,
struct iw_request_info *info,
char *buf, size_t len)
{
char *current_ev = buf;
char *end_buf = buf + len;
struct ieee80211_sta_bss *bss;
spin_lock_bh(&local->sta_bss_lock);
list_for_each_entry(bss, &local->sta_bss_list, list) {
if (buf + len - current_ev <= IW_EV_ADDR_LEN) {
spin_unlock_bh(&local->sta_bss_lock);
return -E2BIG;
}
current_ev = ieee80211_sta_scan_result(local, info, bss,
current_ev, end_buf);
}
spin_unlock_bh(&local->sta_bss_lock);
return current_ev - buf;
}