linux/net/ieee80211/softmac/ieee80211softmac_assoc.c
Johannes Berg 501d857ec9 [IEEE80211]: Fix softmac lockdep reports.
It seems I was actually able to hit this deadlock, on my quad G5 softmac
locks up more often than not. This fixes it by using an own workqueue
that can safely be flushed under RTNL.

Not sure if the patch is correct with the workqueue naming. And don't
think with the patch it doesn't continually lock up. It still does, just
doesn't invoke lockdep warnings all the time.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2007-10-10 16:52:22 -07:00

490 lines
16 KiB
C

/*
* This file contains the softmac's association logic.
*
* Copyright (c) 2005, 2006 Johannes Berg <johannes@sipsolutions.net>
* Joseph Jezak <josejx@gentoo.org>
* Larry Finger <Larry.Finger@lwfinger.net>
* Danny van Dyk <kugelfang@gentoo.org>
* Michael Buesch <mbuesch@freenet.de>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*
* The full GNU General Public License is included in this distribution in the
* file called COPYING.
*/
#include "ieee80211softmac_priv.h"
/*
* Overview
*
* Before you can associate, you have to authenticate.
*
*/
/* Sends out an association request to the desired AP */
static void
ieee80211softmac_assoc(struct ieee80211softmac_device *mac, struct ieee80211softmac_network *net)
{
unsigned long flags;
/* Switch to correct channel for this network */
mac->set_channel(mac->dev, net->channel);
/* Send association request */
ieee80211softmac_send_mgt_frame(mac, net, IEEE80211_STYPE_ASSOC_REQ, 0);
dprintk(KERN_INFO PFX "sent association request!\n");
spin_lock_irqsave(&mac->lock, flags);
mac->associnfo.associated = 0; /* just to make sure */
/* Set a timer for timeout */
/* FIXME: make timeout configurable */
if (likely(mac->running))
queue_delayed_work(mac->wq, &mac->associnfo.timeout, 5 * HZ);
spin_unlock_irqrestore(&mac->lock, flags);
}
void
ieee80211softmac_assoc_timeout(struct work_struct *work)
{
struct ieee80211softmac_device *mac =
container_of(work, struct ieee80211softmac_device,
associnfo.timeout.work);
struct ieee80211softmac_network *n;
mutex_lock(&mac->associnfo.mutex);
/* we might race against ieee80211softmac_handle_assoc_response,
* so make sure only one of us does something */
if (!mac->associnfo.associating)
goto out;
mac->associnfo.associating = 0;
mac->associnfo.bssvalid = 0;
mac->associnfo.associated = 0;
n = ieee80211softmac_get_network_by_bssid_locked(mac, mac->associnfo.bssid);
dprintk(KERN_INFO PFX "assoc request timed out!\n");
ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, n);
out:
mutex_unlock(&mac->associnfo.mutex);
}
void
ieee80211softmac_disassoc(struct ieee80211softmac_device *mac)
{
unsigned long flags;
spin_lock_irqsave(&mac->lock, flags);
if (mac->associnfo.associating)
cancel_delayed_work(&mac->associnfo.timeout);
netif_carrier_off(mac->dev);
mac->associnfo.associated = 0;
mac->associnfo.bssvalid = 0;
mac->associnfo.associating = 0;
ieee80211softmac_init_bss(mac);
ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
spin_unlock_irqrestore(&mac->lock, flags);
}
/* Sends out a disassociation request to the desired AP */
void
ieee80211softmac_send_disassoc_req(struct ieee80211softmac_device *mac, u16 reason)
{
struct ieee80211softmac_network *found;
if (mac->associnfo.bssvalid && mac->associnfo.associated) {
found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
if (found)
ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
}
ieee80211softmac_disassoc(mac);
}
static inline int
we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
{
int idx;
u8 rate;
for (idx = 0; idx < (from_len); idx++) {
rate = (from)[idx];
if (!(rate & IEEE80211_BASIC_RATE_MASK))
continue;
rate &= ~IEEE80211_BASIC_RATE_MASK;
if (!ieee80211softmac_ratesinfo_rate_supported(&mac->ratesinfo, rate))
return 0;
}
return 1;
}
static int
network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
{
/* we cannot associate to networks whose name we don't know */
if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
return 0;
/* do not associate to a network whose BSSBasicRateSet we cannot support */
if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
return 0;
/* do we really need to check the ex rates? */
if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
return 0;
/* assume that users know what they're doing ...
* (note we don't let them select a net we're incompatible with) */
if (mac->associnfo.bssfixed) {
return !memcmp(mac->associnfo.bssid, net->bssid, ETH_ALEN);
}
/* if 'ANY' network requested, take any that doesn't have privacy enabled */
if (mac->associnfo.req_essid.len == 0
&& !(net->capability & WLAN_CAPABILITY_PRIVACY))
return 1;
if (net->ssid_len != mac->associnfo.req_essid.len)
return 0;
if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
return 1;
return 0;
}
static void
ieee80211softmac_assoc_notify_scan(struct net_device *dev, int event_type, void *context)
{
struct ieee80211softmac_device *mac = ieee80211_priv(dev);
ieee80211softmac_assoc_work(&mac->associnfo.work.work);
}
static void
ieee80211softmac_assoc_notify_auth(struct net_device *dev, int event_type, void *context)
{
struct ieee80211softmac_device *mac = ieee80211_priv(dev);
switch (event_type) {
case IEEE80211SOFTMAC_EVENT_AUTHENTICATED:
ieee80211softmac_assoc_work(&mac->associnfo.work.work);
break;
case IEEE80211SOFTMAC_EVENT_AUTH_FAILED:
case IEEE80211SOFTMAC_EVENT_AUTH_TIMEOUT:
ieee80211softmac_disassoc(mac);
break;
}
}
/* This function is called to handle userspace requests (asynchronously) */
void
ieee80211softmac_assoc_work(struct work_struct *work)
{
struct ieee80211softmac_device *mac =
container_of(work, struct ieee80211softmac_device,
associnfo.work.work);
struct ieee80211softmac_network *found = NULL;
struct ieee80211_network *net = NULL, *best = NULL;
int bssvalid;
unsigned long flags;
mutex_lock(&mac->associnfo.mutex);
if (!mac->associnfo.associating)
goto out;
/* ieee80211_disassoc might clear this */
bssvalid = mac->associnfo.bssvalid;
/* meh */
if (mac->associnfo.associated)
ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
/* try to find the requested network in our list, if we found one already */
if (bssvalid || mac->associnfo.bssfixed)
found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
/* Search the ieee80211 networks for this network if we didn't find it by bssid,
* but only if we've scanned at least once (to get a better list of networks to
* select from). If we have not scanned before, the !found logic below will be
* invoked and will scan. */
if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
{
s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
because it cannot follow the best pointer logic. */
spin_lock_irqsave(&mac->ieee->lock, flags);
list_for_each_entry(net, &mac->ieee->network_list, list) {
/* we're supposed to find the network with
* the best signal here, as we're asked to join
* any network with a specific ESSID, and many
* different ones could have that.
*
* I'll for now just go with the reported rssi.
*
* We also should take into account the rateset
* here to find the best BSSID to try.
*/
if (network_matches_request(mac, net)) {
if (!best) {
best = net;
rssi = best->stats.rssi;
continue;
}
/* we already had a matching network, so
* compare their properties to get the
* better of the two ... (see above)
*/
if (rssi < net->stats.rssi) {
best = net;
rssi = best->stats.rssi;
}
}
}
/* if we unlock here, we might get interrupted and the `best'
* pointer could go stale */
if (best) {
found = ieee80211softmac_create_network(mac, best);
/* if found is still NULL, then we got -ENOMEM somewhere */
if (found)
ieee80211softmac_add_network(mac, found);
}
spin_unlock_irqrestore(&mac->ieee->lock, flags);
}
if (!found) {
if (mac->associnfo.scan_retry > 0) {
mac->associnfo.scan_retry--;
/* We know of no such network. Let's scan.
* NB: this also happens if we had no memory to copy the network info...
* Maybe we can hope to have more memory after scanning finishes ;)
*/
dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
if (ieee80211softmac_start_scan(mac)) {
dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
}
goto out;
} else {
mac->associnfo.associating = 0;
mac->associnfo.associated = 0;
dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
/* reset the retry counter for the next user request since we
* break out and don't reschedule ourselves after this point. */
mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
goto out;
}
}
/* reset the retry counter for the next user request since we
* now found a net and will try to associate to it, but not
* schedule this function again. */
mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
mac->associnfo.bssvalid = 1;
memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
/* copy the ESSID for displaying it */
mac->associnfo.associate_essid.len = found->essid.len;
memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
/* we found a network! authenticate (if necessary) and associate to it. */
if (found->authenticating) {
dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
if(!mac->associnfo.assoc_wait) {
mac->associnfo.assoc_wait = 1;
ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
}
goto out;
}
if (!found->authenticated && !found->authenticating) {
/* This relies on the fact that _auth_req only queues the work,
* otherwise adding the notification would be racy. */
if (!ieee80211softmac_auth_req(mac, found)) {
if(!mac->associnfo.assoc_wait) {
dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
mac->associnfo.assoc_wait = 1;
ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
}
} else {
printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
mac->associnfo.assoc_wait = 0;
ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
}
goto out;
}
/* finally! now we can start associating */
mac->associnfo.assoc_wait = 0;
ieee80211softmac_assoc(mac, found);
out:
mutex_unlock(&mac->associnfo.mutex);
}
/* call this to do whatever is necessary when we're associated */
static void
ieee80211softmac_associated(struct ieee80211softmac_device *mac,
struct ieee80211_assoc_response * resp,
struct ieee80211softmac_network *net)
{
u16 cap = le16_to_cpu(resp->capability);
u8 erp_value = net->erp_value;
mac->associnfo.associating = 0;
mac->bssinfo.supported_rates = net->supported_rates;
ieee80211softmac_recalc_txrates(mac);
mac->associnfo.associated = 1;
mac->associnfo.short_preamble_available =
(cap & WLAN_CAPABILITY_SHORT_PREAMBLE) != 0;
ieee80211softmac_process_erp(mac, erp_value);
if (mac->set_bssid_filter)
mac->set_bssid_filter(mac->dev, net->bssid);
memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
netif_carrier_on(mac->dev);
mac->association_id = le16_to_cpup(&resp->aid);
}
/* received frame handling functions */
int
ieee80211softmac_handle_assoc_response(struct net_device * dev,
struct ieee80211_assoc_response * resp,
struct ieee80211_network * _ieee80211_network)
{
/* NOTE: the network parameter has to be mostly ignored by
* this code because it is the ieee80211's pointer
* to the struct, not ours (we made a copy)
*/
struct ieee80211softmac_device *mac = ieee80211_priv(dev);
u16 status = le16_to_cpup(&resp->status);
struct ieee80211softmac_network *network = NULL;
unsigned long flags;
DECLARE_MAC_BUF(mac2);
if (unlikely(!mac->running))
return -ENODEV;
spin_lock_irqsave(&mac->lock, flags);
if (!mac->associnfo.associating) {
/* we race against the timeout function, so make sure
* only one of us can do work */
spin_unlock_irqrestore(&mac->lock, flags);
return 0;
}
network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
/* someone sending us things without us knowing him? Ignore. */
if (!network) {
dprintk(KERN_INFO PFX "Received unrequested assocation response from %s\n",
print_mac(mac2, resp->header.addr3));
spin_unlock_irqrestore(&mac->lock, flags);
return 0;
}
/* now that we know it was for us, we can cancel the timeout */
cancel_delayed_work(&mac->associnfo.timeout);
/* if the association response included an ERP IE, update our saved
* copy */
if (_ieee80211_network->flags & NETWORK_HAS_ERP_VALUE)
network->erp_value = _ieee80211_network->erp_value;
switch (status) {
case 0:
dprintk(KERN_INFO PFX "associated!\n");
ieee80211softmac_associated(mac, resp, network);
ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
break;
case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
if (!network->auth_desynced_once) {
/* there seem to be a few rare cases where our view of
* the world is obscured, or buggy APs that don't DEAUTH
* us properly. So we handle that, but allow it only once.
*/
printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
network->authenticated = 0;
/* we don't want to do this more than once ... */
network->auth_desynced_once = 1;
queue_delayed_work(mac->wq, &mac->associnfo.work, 0);
break;
}
default:
dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
mac->associnfo.associating = 0;
mac->associnfo.bssvalid = 0;
mac->associnfo.associated = 0;
ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
}
spin_unlock_irqrestore(&mac->lock, flags);
return 0;
}
void
ieee80211softmac_try_reassoc(struct ieee80211softmac_device *mac)
{
unsigned long flags;
spin_lock_irqsave(&mac->lock, flags);
mac->associnfo.associating = 1;
queue_delayed_work(mac->wq, &mac->associnfo.work, 0);
spin_unlock_irqrestore(&mac->lock, flags);
}
int
ieee80211softmac_handle_disassoc(struct net_device * dev,
struct ieee80211_disassoc *disassoc)
{
struct ieee80211softmac_device *mac = ieee80211_priv(dev);
if (unlikely(!mac->running))
return -ENODEV;
if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
return 0;
if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
return 0;
dprintk(KERN_INFO PFX "got disassoc frame\n");
ieee80211softmac_disassoc(mac);
ieee80211softmac_try_reassoc(mac);
return 0;
}
int
ieee80211softmac_handle_reassoc_req(struct net_device * dev,
struct ieee80211_reassoc_request * resp)
{
struct ieee80211softmac_device *mac = ieee80211_priv(dev);
struct ieee80211softmac_network *network;
if (unlikely(!mac->running))
return -ENODEV;
network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
if (!network) {
dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
return 0;
}
queue_delayed_work(mac->wq, &mac->associnfo.work, 0);
return 0;
}