[PATCH] softmac: deauthentication implies deassociation

[usb.git] / net / ieee80211 / softmac / ieee80211softmac_assoc.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");

        /* Change the state to associating */
        spin_lock_irqsave(&mac->lock, flags);
        mac->associnfo.associating = 1;
        mac->associated = 0; /* just to make sure */

        /* Set a timer for timeout */
        /* FIXME: make timeout configurable */
        if (likely(mac->running))
                schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
        spin_unlock_irqrestore(&mac->lock, flags);
}

void
ieee80211softmac_assoc_timeout(void *d)
{
        struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
        unsigned long flags;

        spin_lock_irqsave(&mac->lock, flags);
        /* we might race against ieee80211softmac_handle_assoc_response,
         * so make sure only one of us does something */
        if (!mac->associnfo.associating) {
                spin_unlock_irqrestore(&mac->lock, flags);
                return;
        }
        mac->associnfo.associating = 0;
        mac->associnfo.bssvalid = 0;
        mac->associated = 0;
        spin_unlock_irqrestore(&mac->lock, flags);

        dprintk(KERN_INFO PFX "assoc request timed out!\n");
        /* FIXME: we need to know the network here. that requires a bit of restructuring */
        ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
}

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->associated = 0;
        mac->associnfo.bssvalid = 0;
        mac->associnfo.associating = 0;
        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->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, search, found;
        u8 rate, search_rate;

        for (idx = 0; idx < (from_len); idx++) {
                rate = (from)[idx];
                if (!(rate & IEEE80211_BASIC_RATE_MASK))
                        continue;
                found = 0;
                rate &= ~IEEE80211_BASIC_RATE_MASK;
                for (search = 0; search < mac->ratesinfo.count; search++) {
                        search_rate = mac->ratesinfo.rates[search];
                        search_rate &= ~IEEE80211_BASIC_RATE_MASK;
                        if (rate == search_rate) {
                                found = 1;
                                break;
                        }
                }
                if (!found)
                        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(struct net_device *dev, void *context)
{
        struct ieee80211softmac_device *mac = ieee80211_priv(dev);
        ieee80211softmac_assoc_work((void*)mac);
}

/* This function is called to handle userspace requests (asynchronously) */
void
ieee80211softmac_assoc_work(void *d)
{
        struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
        struct ieee80211softmac_network *found = NULL;
        struct ieee80211_network *net = NULL, *best = NULL;
        int bssvalid;
        unsigned long flags;

        /* ieee80211_disassoc might clear this */
        bssvalid = mac->associnfo.bssvalid;

        /* meh */
        if (mac->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) {
                        spin_lock_irqsave(&mac->lock, flags);
                        mac->associnfo.scan_retry--;
                        spin_unlock_irqrestore(&mac->lock, flags);
                
                        /* 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, NULL);
                        if (ieee80211softmac_start_scan(mac))
                                dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
                        return;
                } else {
                        spin_lock_irqsave(&mac->lock, flags);
                        mac->associnfo.associating = 0;
                        mac->associated = 0;
                        spin_unlock_irqrestore(&mac->lock, flags);

                        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);
                        return;
                }
        }

        /* 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->authenticated) {
                /* 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)) {
                        dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
                        ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
                } else {
                        printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
                        ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
                }
                return;
        }
        /* finally! now we can start associating */
        ieee80211softmac_assoc(mac, found);
}

/* 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)
{
        mac->associnfo.associating = 0;
        mac->associated = 1;
        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_do_not_use)
{
        /* NOTE: the network parameter has to be 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;

        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 " MAC_FMT "\n", MAC_ARG(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);

        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;
                                schedule_work(&mac->associnfo.work);
                                break;
                        }
                default:
                        dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
                        mac->associnfo.associating = 0;
                        mac->associnfo.bssvalid = 0;
                        mac->associated = 0;
                        ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
        }
        
        spin_unlock_irqrestore(&mac->lock, flags);
        return 0;
}

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);

        /* try to reassociate */
        schedule_work(&mac->associnfo.work);

        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;
        }
        schedule_work(&mac->associnfo.work);

        return 0;
}