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linux/net/mac80211/scan.c
Johannes Berg 469002983f mac80211: split IBSS/managed code 
This patch splits out the ibss code and data from managed (station) mode.
The reason to do this is to better separate the state machines, and have
the code be contained better so it gets easier to determine what exactly
a given change will affect, that in turn makes it easier to understand.

This is quite some churn, especially because I split sdata->u.sta into
sdata->u.mgd and sdata->u.ibss, but I think it's easier to maintain that
way. I've also shuffled around some code -- null function sending is only
applicable to managed interfaces so put that into that file, some other
functions are needed from various places so put them into util, and also
rearranged the prototypes in ieee80211_i.h accordingly.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-02-27 14:51:42 -05:00

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/*
* Scanning 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.
*/
/* TODO: figure out how to avoid that the "current BSS" expires */
#include <linux/wireless.h>
#include <linux/if_arp.h>
#include <linux/rtnetlink.h>
#include <net/mac80211.h>
#include <net/iw_handler.h>
#include "ieee80211_i.h"
#include "mesh.h"
#define IEEE80211_PROBE_DELAY (HZ / 33)
#define IEEE80211_CHANNEL_TIME (HZ / 33)
#define IEEE80211_PASSIVE_CHANNEL_TIME (HZ / 5)
struct ieee80211_bss *
ieee80211_rx_bss_get(struct ieee80211_local *local, u8 *bssid, int freq,
u8 *ssid, u8 ssid_len)
{
return (void *)cfg80211_get_bss(local->hw.wiphy,
ieee80211_get_channel(local->hw.wiphy,
freq),
bssid, ssid, ssid_len,
0, 0);
}
static void ieee80211_rx_bss_free(struct cfg80211_bss *cbss)
{
struct ieee80211_bss *bss = (void *)cbss;
kfree(bss_mesh_id(bss));
kfree(bss_mesh_cfg(bss));
}
void ieee80211_rx_bss_put(struct ieee80211_local *local,
struct ieee80211_bss *bss)
{
cfg80211_put_bss((struct cfg80211_bss *)bss);
}
struct ieee80211_bss *
ieee80211_bss_info_update(struct ieee80211_local *local,
struct ieee80211_rx_status *rx_status,
struct ieee80211_mgmt *mgmt,
size_t len,
struct ieee802_11_elems *elems,
struct ieee80211_channel *channel,
bool beacon)
{
struct ieee80211_bss *bss;
int clen;
enum cfg80211_signal_type sigtype = CFG80211_SIGNAL_TYPE_NONE;
s32 signal = 0;
if (local->hw.flags & IEEE80211_HW_SIGNAL_DBM) {
sigtype = CFG80211_SIGNAL_TYPE_MBM;
signal = rx_status->signal * 100;
} else if (local->hw.flags & IEEE80211_HW_SIGNAL_UNSPEC) {
sigtype = CFG80211_SIGNAL_TYPE_UNSPEC;
signal = (rx_status->signal * 100) / local->hw.max_signal;
}
bss = (void *)cfg80211_inform_bss_frame(local->hw.wiphy, channel,
mgmt, len, signal, sigtype,
GFP_ATOMIC);
if (!bss)
return NULL;
bss->cbss.free_priv = ieee80211_rx_bss_free;
/* save the ERP value so that it is available at association time */
if (elems->erp_info && elems->erp_info_len >= 1) {
bss->erp_value = elems->erp_info[0];
bss->has_erp_value = 1;
}
if (elems->tim) {
struct ieee80211_tim_ie *tim_ie =
(struct ieee80211_tim_ie *)elems->tim;
bss->dtim_period = tim_ie->dtim_period;
}
/* set default value for buggy APs */
if (!elems->tim || bss->dtim_period == 0)
bss->dtim_period = 1;
bss->supp_rates_len = 0;
if (elems->supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
if (clen > elems->supp_rates_len)
clen = elems->supp_rates_len;
memcpy(&bss->supp_rates[bss->supp_rates_len], elems->supp_rates,
clen);
bss->supp_rates_len += clen;
}
if (elems->ext_supp_rates) {
clen = IEEE80211_MAX_SUPP_RATES - bss->supp_rates_len;
if (clen > elems->ext_supp_rates_len)
clen = elems->ext_supp_rates_len;
memcpy(&bss->supp_rates[bss->supp_rates_len],
elems->ext_supp_rates, clen);
bss->supp_rates_len += clen;
}
bss->wmm_used = elems->wmm_param || elems->wmm_info;
if (!beacon)
bss->last_probe_resp = jiffies;
return bss;
}
void ieee80211_rx_bss_remove(struct ieee80211_sub_if_data *sdata, u8 *bssid,
int freq, u8 *ssid, u8 ssid_len)
{
struct ieee80211_bss *bss;
struct ieee80211_local *local = sdata->local;
bss = ieee80211_rx_bss_get(local, bssid, freq, ssid, ssid_len);
if (bss) {
cfg80211_unlink_bss(local->hw.wiphy, (void *)bss);
ieee80211_rx_bss_put(local, bss);
}
}
ieee80211_rx_result
ieee80211_scan_rx(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
struct ieee80211_rx_status *rx_status)
{
struct ieee80211_mgmt *mgmt;
struct ieee80211_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,
channel, beacon);
if (bss)
ieee80211_rx_bss_put(sdata->local, bss);
dev_kfree_skb(skb);
return RX_QUEUED;
}
void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
{
struct ieee80211_local *local = hw_to_local(hw);
struct ieee80211_sub_if_data *sdata;
if (WARN_ON(!local->hw_scanning && !local->sw_scanning))
return;
if (WARN_ON(!local->scan_req))
return;
if (local->scan_req != &local->int_scan_req)
cfg80211_scan_done(local->scan_req, aborted);
local->scan_req = NULL;
local->last_scan_completed = jiffies;
if (local->hw_scanning) {
local->hw_scanning = false;
/*
* Somebody might have requested channel change during scan
* that we won't have acted upon, try now. ieee80211_hw_config
* will set the flag based on actual changes.
*/
ieee80211_hw_config(local, 0);
goto done;
}
local->sw_scanning = false;
ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
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);
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
/* Tell AP we're back */
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.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);
/* re-enable beaconing */
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_ADHOC ||
sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
ieee80211_if_config(sdata,
IEEE80211_IFCC_BEACON_ENABLED);
}
mutex_unlock(&local->iflist_mtx);
done:
ieee80211_mlme_notify_scan_completed(local);
ieee80211_ibss_notify_scan_completed(local);
ieee80211_mesh_notify_scan_completed(local);
}
EXPORT_SYMBOL(ieee80211_scan_completed);
void ieee80211_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_channel *chan;
int skip, i;
unsigned long next_delay = 0;
/*
* Avoid re-scheduling when the sdata is going away.
*/
if (!netif_running(sdata->dev))
return;
switch (local->scan_state) {
case SCAN_SET_CHANNEL:
/* if no more bands/channels left, complete scan */
if (local->scan_channel_idx >= local->scan_req->n_channels) {
ieee80211_scan_completed(local_to_hw(local), false);
return;
}
skip = 0;
chan = local->scan_req->channels[local->scan_channel_idx];
if (chan->flags & IEEE80211_CHAN_DISABLED ||
(sdata->vif.type == NL80211_IFTYPE_ADHOC &&
chan->flags & IEEE80211_CHAN_NO_IBSS))
skip = 1;
if (!skip) {
local->scan_channel = chan;
if (ieee80211_hw_config(local,
IEEE80211_CONF_CHANGE_CHANNEL))
skip = 1;
}
/* advance state machine to next channel/band */
local->scan_channel_idx++;
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 ||
!local->scan_req->n_ssids)
break;
for (i = 0; i < local->scan_req->n_ssids; i++)
ieee80211_send_probe_req(
sdata, NULL,
local->scan_req->ssids[i].ssid,
local->scan_req->ssids[i].ssid_len);
next_delay = IEEE80211_CHANNEL_TIME;
break;
}
queue_delayed_work(local->hw.workqueue, &local->scan_work,
next_delay);
}
int ieee80211_start_scan(struct ieee80211_sub_if_data *scan_sdata,
struct cfg80211_scan_request *req)
{
struct ieee80211_local *local = scan_sdata->local;
struct ieee80211_sub_if_data *sdata;
if (!req)
return -EINVAL;
if (local->scan_req && local->scan_req != req)
return -EBUSY;
local->scan_req = req;
/* 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->sw_scanning || local->hw_scanning) {
if (local->scan_sdata == scan_sdata)
return 0;
return -EBUSY;
}
if (local->ops->hw_scan) {
int rc;
local->hw_scanning = true;
rc = local->ops->hw_scan(local_to_hw(local), req);
if (rc) {
local->hw_scanning = false;
return rc;
}
local->scan_sdata = scan_sdata;
return 0;
}
local->sw_scanning = true;
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!netif_running(sdata->dev))
continue;
/* disable beaconing */
if (sdata->vif.type == NL80211_IFTYPE_AP ||
sdata->vif.type == NL80211_IFTYPE_ADHOC ||
sdata->vif.type == NL80211_IFTYPE_MESH_POINT)
ieee80211_if_config(sdata,
IEEE80211_IFCC_BEACON_ENABLED);
if (sdata->vif.type == NL80211_IFTYPE_STATION) {
if (sdata->u.mgd.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);
}
mutex_unlock(&local->iflist_mtx);
local->scan_state = SCAN_SET_CHANNEL;
local->scan_channel_idx = 0;
local->scan_sdata = scan_sdata;
local->scan_req = req;
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_request_scan(struct ieee80211_sub_if_data *sdata,
struct cfg80211_scan_request *req)
{
struct ieee80211_local *local = sdata->local;
struct ieee80211_if_managed *ifmgd;
if (!req)
return -EINVAL;
if (local->scan_req && local->scan_req != req)
return -EBUSY;
local->scan_req = req;
if (sdata->vif.type != NL80211_IFTYPE_STATION)
return ieee80211_start_scan(sdata, req);
/*
* STA has a state machine that might need to defer scanning
* while it's trying to associate/authenticate, therefore we
* queue it up to the state machine in that case.
*/
if (local->sw_scanning || local->hw_scanning) {
if (local->scan_sdata == sdata)
return 0;
return -EBUSY;
}
ifmgd = &sdata->u.mgd;
set_bit(IEEE80211_STA_REQ_SCAN, &ifmgd->request);
queue_work(local->hw.workqueue, &ifmgd->work);
return 0;
}
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