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>

1 files changed, 888 insertions, 0 deletions

diff --git a/net/mac80211/ibss.c b/net/mac80211/ibss.c
new file mode 100644
index 000000000000..1bbfc7029879
--- /dev/null
+++ b/net/mac80211/ibss.c
@@ -0,0 +1,888 @@
+/*
+ * IBSS mode implementation
+ * Copyright 2003-2008, Jouni Malinen <j@w1.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>
+ * Copyright 2009, Johannes Berg <johannes@sipsolutions.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/delay.h>
+#include <linux/if_ether.h>
+#include <linux/skbuff.h>
+#include <linux/if_arp.h>
+#include <linux/etherdevice.h>
+#include <linux/rtnetlink.h>
+#include <net/mac80211.h>
+#include <asm/unaligned.h>
+
+#include "ieee80211_i.h"
+#include "rate.h"
+
+#define IEEE80211_SCAN_INTERVAL (2 * HZ)
+#define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
+#define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)
+
+#define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
+#define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
+
+#define IEEE80211_IBSS_MAX_STA_ENTRIES 128
+
+
+static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
+                                        struct ieee80211_mgmt *mgmt,
+                                        size_t len)
+{
+        u16 auth_alg, auth_transaction, status_code;
+
+        if (len < 24 + 6)
+                return;
+
+        auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
+        auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
+        status_code = le16_to_cpu(mgmt->u.auth.status_code);
+
+        /*
+         * IEEE 802.11 standard does not require authentication in IBSS
+         * networks and most implementations do not seem to use it.
+         * However, try to reply to authentication attempts if someone
+         * has actually implemented this.
+         */
+        if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
+                ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
+                                    sdata->u.ibss.bssid, 0);
+}
+
+static int __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
+                                     const u8 *bssid, const int beacon_int,
+                                     const int freq,
+                                     const size_t supp_rates_len,
+                                     const u8 *supp_rates,
+                                     const u16 capability)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+        int res = 0, rates, i, j;
+        struct sk_buff *skb;
+        struct ieee80211_mgmt *mgmt;
+        u8 *pos;
+        struct ieee80211_supported_band *sband;
+        union iwreq_data wrqu;
+
+        if (local->ops->reset_tsf) {
+                /* Reset own TSF to allow time synchronization work. */
+                local->ops->reset_tsf(local_to_hw(local));
+        }
+
+        if ((ifibss->flags & IEEE80211_IBSS_PREV_BSSID_SET) &&
+           memcmp(ifibss->bssid, bssid, ETH_ALEN) == 0)
+                return res;
+
+        skb = dev_alloc_skb(local->hw.extra_tx_headroom + 400);
+        if (!skb) {
+                printk(KERN_DEBUG "%s: failed to allocate buffer for probe "
+                       "response\n", sdata->dev->name);
+                return -ENOMEM;
+        }
+
+        if (!(ifibss->flags & IEEE80211_IBSS_PREV_BSSID_SET)) {
+                /* Remove possible STA entries from other IBSS networks. */
+                sta_info_flush_delayed(sdata);
+        }
+
+        memcpy(ifibss->bssid, bssid, ETH_ALEN);
+        res = ieee80211_if_config(sdata, IEEE80211_IFCC_BSSID);
+        if (res)
+                return res;
+
+        local->hw.conf.beacon_int = beacon_int >= 10 ? beacon_int : 10;
+
+        sdata->drop_unencrypted = capability &
+                WLAN_CAPABILITY_PRIVACY ? 1 : 0;
+
+        res = ieee80211_set_freq(sdata, freq);
+
+        if (res)
+                return res;
+
+        sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
+
+        /* Build IBSS probe response */
+
+        skb_reserve(skb, local->hw.extra_tx_headroom);
+
+        mgmt = (struct ieee80211_mgmt *)
+                skb_put(skb, 24 + sizeof(mgmt->u.beacon));
+        memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
+        mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
+                                          IEEE80211_STYPE_PROBE_RESP);
+        memset(mgmt->da, 0xff, ETH_ALEN);
+        memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
+        memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
+        mgmt->u.beacon.beacon_int =
+                cpu_to_le16(local->hw.conf.beacon_int);
+        mgmt->u.beacon.capab_info = cpu_to_le16(capability);
+
+        pos = skb_put(skb, 2 + ifibss->ssid_len);
+        *pos++ = WLAN_EID_SSID;
+        *pos++ = ifibss->ssid_len;
+        memcpy(pos, ifibss->ssid, ifibss->ssid_len);
+
+        rates = supp_rates_len;
+        if (rates > 8)
+                rates = 8;
+        pos = skb_put(skb, 2 + rates);
+        *pos++ = WLAN_EID_SUPP_RATES;
+        *pos++ = rates;
+        memcpy(pos, supp_rates, rates);
+
+        if (sband->band == IEEE80211_BAND_2GHZ) {
+                pos = skb_put(skb, 2 + 1);
+                *pos++ = WLAN_EID_DS_PARAMS;
+                *pos++ = 1;
+                *pos++ = ieee80211_frequency_to_channel(freq);
+        }
+
+        pos = skb_put(skb, 2 + 2);
+        *pos++ = WLAN_EID_IBSS_PARAMS;
+        *pos++ = 2;
+        /* FIX: set ATIM window based on scan results */
+        *pos++ = 0;
+        *pos++ = 0;
+
+        if (supp_rates_len > 8) {
+                rates = supp_rates_len - 8;
+                pos = skb_put(skb, 2 + rates);
+                *pos++ = WLAN_EID_EXT_SUPP_RATES;
+                *pos++ = rates;
+                memcpy(pos, &supp_rates[8], rates);
+        }
+
+        ifibss->probe_resp = skb;
+
+        ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON |
+                                   IEEE80211_IFCC_BEACON_ENABLED);
+
+
+        rates = 0;
+        for (i = 0; i < supp_rates_len; i++) {
+                int bitrate = (supp_rates[i] & 0x7f) * 5;
+                for (j = 0; j < sband->n_bitrates; j++)
+                        if (sband->bitrates[j].bitrate == bitrate)
+                                rates |= BIT(j);
+        }
+
+        ieee80211_sta_def_wmm_params(sdata, supp_rates_len, supp_rates);
+
+        ifibss->flags |= IEEE80211_IBSS_PREV_BSSID_SET;
+        ifibss->state = IEEE80211_IBSS_MLME_JOINED;
+        mod_timer(&ifibss->timer, jiffies + IEEE80211_IBSS_MERGE_INTERVAL);
+
+        memset(&wrqu, 0, sizeof(wrqu));
+        memcpy(wrqu.ap_addr.sa_data, bssid, ETH_ALEN);
+        wireless_send_event(sdata->dev, SIOCGIWAP, &wrqu, NULL);
+
+        return res;
+}
+
+static int ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
+                                   struct ieee80211_bss *bss)
+{
+        return __ieee80211_sta_join_ibss(sdata,
+                                         bss->cbss.bssid,
+                                         bss->cbss.beacon_interval,
+                                         bss->cbss.channel->center_freq,
+                                         bss->supp_rates_len, bss->supp_rates,
+                                         bss->cbss.capability);
+}
+
+static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
+                                  struct ieee80211_mgmt *mgmt,
+                                  size_t len,
+                                  struct ieee80211_rx_status *rx_status,
+                                  struct ieee802_11_elems *elems,
+                                  bool beacon)
+{
+        struct ieee80211_local *local = sdata->local;
+        int freq;
+        struct ieee80211_bss *bss;
+        struct sta_info *sta;
+        struct ieee80211_channel *channel;
+        u64 beacon_timestamp, rx_timestamp;
+        u32 supp_rates = 0;
+        enum ieee80211_band band = rx_status->band;
+
+        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(local->hw.wiphy, freq);
+
+        if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
+                return;
+
+        if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
+            memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
+                supp_rates = ieee80211_sta_get_rates(local, elems, band);
+
+                rcu_read_lock();
+
+                sta = sta_info_get(local, mgmt->sa);
+                if (sta) {
+                        u32 prev_rates;
+
+                        prev_rates = sta->sta.supp_rates[band];
+                        /* make sure mandatory rates are always added */
+                        sta->sta.supp_rates[band] = supp_rates |
+                                ieee80211_mandatory_rates(local, band);
+
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+                        if (sta->sta.supp_rates[band] != prev_rates)
+                                printk(KERN_DEBUG "%s: updated supp_rates set "
+                                    "for %pM based on beacon info (0x%llx | "
+                                    "0x%llx -> 0x%llx)\n",
+                                    sdata->dev->name,
+                                    sta->sta.addr,
+                                    (unsigned long long) prev_rates,
+                                    (unsigned long long) supp_rates,
+                                    (unsigned long long) sta->sta.supp_rates[band]);
+#endif
+                } else
+                        ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
+
+                rcu_read_unlock();
+        }
+
+        bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
+                                        channel, beacon);
+        if (!bss)
+                return;
+
+        /* was just updated in ieee80211_bss_info_update */
+        beacon_timestamp = bss->cbss.tsf;
+
+        /* check if we need to merge IBSS */
+
+        /* merge only on beacons (???) */
+        if (!beacon)
+                goto put_bss;
+
+        /* we use a fixed BSSID */
+        if (sdata->u.ibss.flags & IEEE80211_IBSS_BSSID_SET)
+                goto put_bss;
+
+        /* not an IBSS */
+        if (!(bss->cbss.capability & WLAN_CAPABILITY_IBSS))
+                goto put_bss;
+
+        /* different channel */
+        if (bss->cbss.channel != local->oper_channel)
+                goto put_bss;
+
+        /* different SSID */
+        if (elems->ssid_len != sdata->u.ibss.ssid_len ||
+            memcmp(elems->ssid, sdata->u.ibss.ssid,
+                                sdata->u.ibss.ssid_len))
+                goto put_bss;
+
+        if (rx_status->flag & RX_FLAG_TSFT) {
+                /*
+                 * For correct IBSS merging we need mactime; since mactime is
+                 * defined as the time the first data symbol of the frame hits
+                 * the PHY, and the timestamp of the beacon is defined as "the
+                 * time that the data symbol containing the first bit of the
+                 * timestamp is transmitted to the PHY plus the transmitting
+                 * STA's delays through its local PHY from the MAC-PHY
+                 * interface to its interface with the WM" (802.11 11.1.2)
+                 * - equals the time this bit arrives at the receiver - we have
+                 * to take into account the offset between the two.
+                 *
+                 * E.g. at 1 MBit that means mactime is 192 usec earlier
+                 * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
+                 */
+                int rate;
+
+                if (rx_status->flag & RX_FLAG_HT)
+                        rate = 65; /* TODO: HT rates */
+                else
+                        rate = local->hw.wiphy->bands[band]->
+                                bitrates[rx_status->rate_idx].bitrate;
+
+                rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
+        } else if (local && local->ops && local->ops->get_tsf)
+                /* second best option: get current TSF */
+                rx_timestamp = local->ops->get_tsf(local_to_hw(local));
+        else
+                /* can't merge without knowing the TSF */
+                rx_timestamp = -1LLU;
+
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
+               "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
+               mgmt->sa, mgmt->bssid,
+               (unsigned long long)rx_timestamp,
+               (unsigned long long)beacon_timestamp,
+               (unsigned long long)(rx_timestamp - beacon_timestamp),
+               jiffies);
+#endif
+
+        if (beacon_timestamp > rx_timestamp) {
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+                printk(KERN_DEBUG "%s: beacon TSF higher than "
+                       "local TSF - IBSS merge with BSSID %pM\n",
+                       sdata->dev->name, mgmt->bssid);
+#endif
+                ieee80211_sta_join_ibss(sdata, bss);
+                ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
+        }
+
+ put_bss:
+        ieee80211_rx_bss_put(local, bss);
+}
+
+/*
+ * Add a new IBSS station, will also be called by the RX code when,
+ * in IBSS mode, receiving a frame from a yet-unknown station, hence
+ * must be callable in atomic context.
+ */
+struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
+                                        u8 *bssid,u8 *addr, u32 supp_rates)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct sta_info *sta;
+        int band = local->hw.conf.channel->band;
+
+        /* TODO: Could consider removing the least recently used entry and
+         * allow new one to be added. */
+        if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
+                if (net_ratelimit()) {
+                        printk(KERN_DEBUG "%s: No room for a new IBSS STA "
+                               "entry %pM\n", sdata->dev->name, addr);
+                }
+                return NULL;
+        }
+
+        if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
+                return NULL;
+
+#ifdef CONFIG_MAC80211_VERBOSE_DEBUG
+        printk(KERN_DEBUG "%s: Adding new IBSS station %pM (dev=%s)\n",
+               wiphy_name(local->hw.wiphy), addr, sdata->dev->name);
+#endif
+
+        sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
+        if (!sta)
+                return NULL;
+
+        set_sta_flags(sta, WLAN_STA_AUTHORIZED);
+
+        /* make sure mandatory rates are always added */
+        sta->sta.supp_rates[band] = supp_rates |
+                        ieee80211_mandatory_rates(local, band);
+
+        rate_control_rate_init(sta);
+
+        if (sta_info_insert(sta))
+                return NULL;
+
+        return sta;
+}
+
+static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_local *local = sdata->local;
+        int active = 0;
+        struct sta_info *sta;
+
+        rcu_read_lock();
+
+        list_for_each_entry_rcu(sta, &local->sta_list, list) {
+                if (sta->sdata == sdata &&
+                    time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
+                               jiffies)) {
+                        active++;
+                        break;
+                }
+        }
+
+        rcu_read_unlock();
+
+        return active;
+}
+
+
+static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+        mod_timer(&ifibss->timer, jiffies + IEEE80211_IBSS_MERGE_INTERVAL);
+
+        ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
+        if (ieee80211_sta_active_ibss(sdata))
+                return;
+
+        if ((ifibss->flags & IEEE80211_IBSS_BSSID_SET) &&
+            (!(ifibss->flags & IEEE80211_IBSS_AUTO_CHANNEL_SEL)))
+                return;
+
+        printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
+               "IBSS networks with same SSID (merge)\n", sdata->dev->name);
+
+        /* XXX maybe racy? */
+        if (sdata->local->scan_req)
+                return;
+
+        memcpy(sdata->local->int_scan_req.ssids[0].ssid,
+               ifibss->ssid, IEEE80211_MAX_SSID_LEN);
+        sdata->local->int_scan_req.ssids[0].ssid_len = ifibss->ssid_len;
+        ieee80211_request_scan(sdata, &sdata->local->int_scan_req);
+}
+
+static int ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_supported_band *sband;
+        u8 *pos;
+        u8 bssid[ETH_ALEN];
+        u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
+        u16 capability;
+        int i;
+
+        if (ifibss->flags & IEEE80211_IBSS_BSSID_SET) {
+                memcpy(bssid, ifibss->bssid, ETH_ALEN);
+        } else {
+                /* Generate random, not broadcast, locally administered BSSID. Mix in
+                 * own MAC address to make sure that devices that do not have proper
+                 * random number generator get different BSSID. */
+                get_random_bytes(bssid, ETH_ALEN);
+                for (i = 0; i < ETH_ALEN; i++)
+                        bssid[i] ^= sdata->dev->dev_addr[i];
+                bssid[0] &= ~0x01;
+                bssid[0] |= 0x02;
+        }
+
+        printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
+               sdata->dev->name, bssid);
+
+        sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
+
+        if (local->hw.conf.beacon_int == 0)
+                local->hw.conf.beacon_int = 100;
+
+        capability = WLAN_CAPABILITY_IBSS;
+
+        if (sdata->default_key)
+                capability |= WLAN_CAPABILITY_PRIVACY;
+        else
+                sdata->drop_unencrypted = 0;
+
+        pos = supp_rates;
+        for (i = 0; i < sband->n_bitrates; i++) {
+                int rate = sband->bitrates[i].bitrate;
+                *pos++ = (u8) (rate / 5);
+        }
+
+        return __ieee80211_sta_join_ibss(sdata,
+                                         bssid, local->hw.conf.beacon_int,
+                                         local->hw.conf.channel->center_freq,
+                                         sband->n_bitrates, supp_rates,
+                                         capability);
+}
+
+static int ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_bss *bss;
+        const u8 *bssid = NULL;
+        int active_ibss;
+
+        if (ifibss->ssid_len == 0)
+                return -EINVAL;
+
+        active_ibss = ieee80211_sta_active_ibss(sdata);
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
+               sdata->dev->name, active_ibss);
+#endif /* CONFIG_MAC80211_IBSS_DEBUG */
+
+        if (active_ibss)
+                return 0;
+
+        if (ifibss->flags & IEEE80211_IBSS_BSSID_SET)
+                bssid = ifibss->bssid;
+        bss = (void *)cfg80211_get_bss(local->hw.wiphy, NULL, bssid,
+                                       ifibss->ssid, ifibss->ssid_len,
+                                       WLAN_CAPABILITY_IBSS,
+                                       WLAN_CAPABILITY_IBSS);
+
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        if (bss)
+                printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
+                       "%pM\n", bss->cbss.bssid, ifibss->bssid);
+#endif /* CONFIG_MAC80211_IBSS_DEBUG */
+
+        if (bss &&
+            (!(ifibss->flags & IEEE80211_IBSS_PREV_BSSID_SET) ||
+             memcmp(ifibss->bssid, bss->cbss.bssid, ETH_ALEN))) {
+                int ret;
+
+                printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
+                       " based on configured SSID\n",
+                       sdata->dev->name, bss->cbss.bssid);
+
+                ret = ieee80211_sta_join_ibss(sdata, bss);
+                ieee80211_rx_bss_put(local, bss);
+                return ret;
+        } else if (bss)
+                ieee80211_rx_bss_put(local, bss);
+
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        printk(KERN_DEBUG "   did not try to join ibss\n");
+#endif /* CONFIG_MAC80211_IBSS_DEBUG */
+
+        /* Selected IBSS not found in current scan results - try to scan */
+        if (ifibss->state == IEEE80211_IBSS_MLME_JOINED &&
+            !ieee80211_sta_active_ibss(sdata)) {
+                mod_timer(&ifibss->timer, jiffies +
+                                          IEEE80211_IBSS_MERGE_INTERVAL);
+        } else if (time_after(jiffies, local->last_scan_completed +
+                                        IEEE80211_SCAN_INTERVAL)) {
+                printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
+                       "join\n", sdata->dev->name);
+
+                /* XXX maybe racy? */
+                if (local->scan_req)
+                        return -EBUSY;
+
+                memcpy(local->int_scan_req.ssids[0].ssid,
+                       ifibss->ssid, IEEE80211_MAX_SSID_LEN);
+                local->int_scan_req.ssids[0].ssid_len = ifibss->ssid_len;
+                return ieee80211_request_scan(sdata, &local->int_scan_req);
+        } else if (ifibss->state != IEEE80211_IBSS_MLME_JOINED) {
+                int interval = IEEE80211_SCAN_INTERVAL;
+
+                if (time_after(jiffies, ifibss->ibss_join_req +
+                               IEEE80211_IBSS_JOIN_TIMEOUT)) {
+                        if (!(local->oper_channel->flags &
+                                                IEEE80211_CHAN_NO_IBSS))
+                                return ieee80211_sta_create_ibss(sdata);
+                        printk(KERN_DEBUG "%s: IBSS not allowed on"
+                               " %d MHz\n", sdata->dev->name,
+                               local->hw.conf.channel->center_freq);
+
+                        /* No IBSS found - decrease scan interval and continue
+                         * scanning. */
+                        interval = IEEE80211_SCAN_INTERVAL_SLOW;
+                }
+
+                ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
+                mod_timer(&ifibss->timer, jiffies + interval);
+                return 0;
+        }
+
+        return 0;
+}
+
+static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
+                                        struct ieee80211_mgmt *mgmt,
+                                        size_t len)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+        int tx_last_beacon;
+        struct sk_buff *skb;
+        struct ieee80211_mgmt *resp;
+        u8 *pos, *end;
+
+        if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
+            len < 24 + 2 || !ifibss->probe_resp)
+                return;
+
+        if (local->ops->tx_last_beacon)
+                tx_last_beacon = local->ops->tx_last_beacon(local_to_hw(local));
+        else
+                tx_last_beacon = 1;
+
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
+               " (tx_last_beacon=%d)\n",
+               sdata->dev->name, mgmt->sa, mgmt->da,
+               mgmt->bssid, tx_last_beacon);
+#endif /* CONFIG_MAC80211_IBSS_DEBUG */
+
+        if (!tx_last_beacon)
+                return;
+
+        if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
+            memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
+                return;
+
+        end = ((u8 *) mgmt) + len;
+        pos = mgmt->u.probe_req.variable;
+        if (pos[0] != WLAN_EID_SSID ||
+            pos + 2 + pos[1] > end) {
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+                printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
+                       "from %pM\n",
+                       sdata->dev->name, mgmt->sa);
+#endif
+                return;
+        }
+        if (pos[1] != 0 &&
+            (pos[1] != ifibss->ssid_len ||
+             memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len) != 0)) {
+                /* Ignore ProbeReq for foreign SSID */
+                return;
+        }
+
+        /* Reply with ProbeResp */
+        skb = skb_copy(ifibss->probe_resp, GFP_KERNEL);
+        if (!skb)
+                return;
+
+        resp = (struct ieee80211_mgmt *) skb->data;
+        memcpy(resp->da, mgmt->sa, ETH_ALEN);
+#ifdef CONFIG_MAC80211_IBSS_DEBUG
+        printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
+               sdata->dev->name, resp->da);
+#endif /* CONFIG_MAC80211_IBSS_DEBUG */
+        ieee80211_tx_skb(sdata, skb, 0);
+}
+
+static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
+                                         struct ieee80211_mgmt *mgmt,
+                                         size_t len,
+                                         struct ieee80211_rx_status *rx_status)
+{
+        size_t baselen;
+        struct ieee802_11_elems elems;
+
+        if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
+                return; /* ignore ProbeResp to foreign address */
+
+        baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
+        if (baselen > len)
+                return;
+
+        ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
+                                &elems);
+
+        ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
+}
+
+static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
+                                     struct ieee80211_mgmt *mgmt,
+                                     size_t len,
+                                     struct ieee80211_rx_status *rx_status)
+{
+        size_t baselen;
+        struct ieee802_11_elems elems;
+
+        /* Process beacon from the current BSS */
+        baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
+        if (baselen > len)
+                return;
+
+        ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
+
+        ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
+}
+
+static void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
+                                          struct sk_buff *skb)
+{
+        struct ieee80211_rx_status *rx_status;
+        struct ieee80211_mgmt *mgmt;
+        u16 fc;
+
+        rx_status = (struct ieee80211_rx_status *) skb->cb;
+        mgmt = (struct ieee80211_mgmt *) skb->data;
+        fc = le16_to_cpu(mgmt->frame_control);
+
+        switch (fc & IEEE80211_FCTL_STYPE) {
+        case IEEE80211_STYPE_PROBE_REQ:
+                ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
+                break;
+        case IEEE80211_STYPE_PROBE_RESP:
+                ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
+                                             rx_status);
+                break;
+        case IEEE80211_STYPE_BEACON:
+                ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
+                                         rx_status);
+                break;
+        case IEEE80211_STYPE_AUTH:
+                ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
+                break;
+        }
+
+        kfree_skb(skb);
+}
+
+static void ieee80211_ibss_work(struct work_struct *work)
+{
+        struct ieee80211_sub_if_data *sdata =
+                container_of(work, struct ieee80211_sub_if_data, u.ibss.work);
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_if_ibss *ifibss;
+        struct sk_buff *skb;
+
+        if (!netif_running(sdata->dev))
+                return;
+
+        if (local->sw_scanning || local->hw_scanning)
+                return;
+
+        if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_ADHOC))
+                return;
+        ifibss = &sdata->u.ibss;
+
+        while ((skb = skb_dequeue(&ifibss->skb_queue)))
+                ieee80211_ibss_rx_queued_mgmt(sdata, skb);
+
+        if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
+                return;
+
+        switch (ifibss->state) {
+        case IEEE80211_IBSS_MLME_SEARCH:
+                ieee80211_sta_find_ibss(sdata);
+                break;
+        case IEEE80211_IBSS_MLME_JOINED:
+                ieee80211_sta_merge_ibss(sdata);
+                break;
+        default:
+                WARN_ON(1);
+                break;
+        }
+}
+
+static void ieee80211_ibss_timer(unsigned long data)
+{
+        struct ieee80211_sub_if_data *sdata =
+                (struct ieee80211_sub_if_data *) data;
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+        struct ieee80211_local *local = sdata->local;
+
+        set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
+        queue_work(local->hw.workqueue, &ifibss->work);
+}
+
+void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+        INIT_WORK(&ifibss->work, ieee80211_ibss_work);
+        setup_timer(&ifibss->timer, ieee80211_ibss_timer,
+                    (unsigned long) sdata);
+        skb_queue_head_init(&ifibss->skb_queue);
+
+        ifibss->flags |= IEEE80211_IBSS_AUTO_BSSID_SEL |
+                        IEEE80211_IBSS_AUTO_CHANNEL_SEL;
+}
+
+int ieee80211_ibss_set_ssid(struct ieee80211_sub_if_data *sdata, char *ssid, size_t len)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+        if (len > IEEE80211_MAX_SSID_LEN)
+                return -EINVAL;
+
+        if (ifibss->ssid_len != len || memcmp(ifibss->ssid, ssid, len) != 0) {
+                memset(ifibss->ssid, 0, sizeof(ifibss->ssid));
+                memcpy(ifibss->ssid, ssid, len);
+                ifibss->ssid_len = len;
+        }
+
+        ifibss->flags &= ~IEEE80211_IBSS_PREV_BSSID_SET;
+
+        if (len)
+                ifibss->flags |= IEEE80211_IBSS_SSID_SET;
+        else
+                ifibss->flags &= ~IEEE80211_IBSS_SSID_SET;
+
+        ifibss->ibss_join_req = jiffies;
+        ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
+        return ieee80211_sta_find_ibss(sdata);
+}
+
+int ieee80211_ibss_get_ssid(struct ieee80211_sub_if_data *sdata, char *ssid, size_t *len)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+        memcpy(ssid, ifibss->ssid, ifibss->ssid_len);
+        *len = ifibss->ssid_len;
+
+        return 0;
+}
+
+int ieee80211_ibss_set_bssid(struct ieee80211_sub_if_data *sdata, u8 *bssid)
+{
+        struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
+
+        if (is_valid_ether_addr(bssid)) {
+                memcpy(ifibss->bssid, bssid, ETH_ALEN);
+                ifibss->flags |= IEEE80211_IBSS_BSSID_SET;
+        } else {
+                memset(ifibss->bssid, 0, ETH_ALEN);
+                ifibss->flags &= ~IEEE80211_IBSS_BSSID_SET;
+        }
+
+        if (netif_running(sdata->dev)) {
+                if (ieee80211_if_config(sdata, IEEE80211_IFCC_BSSID)) {
+                        printk(KERN_DEBUG "%s: Failed to config new BSSID to "
+                               "the low-level driver\n", sdata->dev->name);
+                }
+        }
+
+        return ieee80211_ibss_set_ssid(sdata, ifibss->ssid, ifibss->ssid_len);
+}
+
+/* scan finished notification */
+void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
+{
+        struct ieee80211_sub_if_data *sdata = local->scan_sdata;
+        struct ieee80211_if_ibss *ifibss;
+
+        if (sdata && sdata->vif.type == NL80211_IFTYPE_ADHOC) {
+                ifibss = &sdata->u.ibss;
+                if ((!(ifibss->flags & IEEE80211_IBSS_PREV_BSSID_SET)) ||
+                    !ieee80211_sta_active_ibss(sdata))
+                        ieee80211_sta_find_ibss(sdata);
+        }
+}
+
+ieee80211_rx_result
+ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
+                       struct ieee80211_rx_status *rx_status)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_mgmt *mgmt;
+        u16 fc;
+
+        if (skb->len < 24)
+                return RX_DROP_MONITOR;
+
+        mgmt = (struct ieee80211_mgmt *) skb->data;
+        fc = le16_to_cpu(mgmt->frame_control);
+
+        switch (fc & IEEE80211_FCTL_STYPE) {
+        case IEEE80211_STYPE_PROBE_RESP:
+        case IEEE80211_STYPE_BEACON:
+                memcpy(skb->cb, rx_status, sizeof(*rx_status));
+        case IEEE80211_STYPE_PROBE_REQ:
+        case IEEE80211_STYPE_AUTH:
+                skb_queue_tail(&sdata->u.ibss.skb_queue, skb);
+                queue_work(local->hw.workqueue, &sdata->u.ibss.work);
+                return RX_QUEUED;
+        }
+
+        return RX_DROP_MONITOR;
+}