net/mac80211/ibss.c

   1 /*
   2  * IBSS mode implementation
   3  * Copyright 2003-2008, Jouni Malinen <j@w1.fi>
   4  * Copyright 2004, Instant802 Networks, Inc.
   5  * Copyright 2005, Devicescape Software, Inc.
   6  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   7  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
   8  * Copyright 2009, Johannes Berg <johannes@sipsolutions.net>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/delay.h>
  16 #include <linux/if_ether.h>
  17 #include <linux/skbuff.h>
  18 #include <linux/if_arp.h>
  19 #include <linux/etherdevice.h>
  20 #include <linux/rtnetlink.h>
  21 #include <net/mac80211.h>
  22 #include <asm/unaligned.h>
  23
  24 #include "ieee80211_i.h"
  25 #include "driver-ops.h"
  26 #include "rate.h"
  27
  28 #define IEEE80211_SCAN_INTERVAL (2 * HZ)
  29 #define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
  30 #define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)
  31
  32 #define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
  33 #define IEEE80211_IBSS_MERGE_DELAY 0x400000
  34 #define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
  35
  36 #define IEEE80211_IBSS_MAX_STA_ENTRIES 128
  37
  38
  39 static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
  40                                         struct ieee80211_mgmt *mgmt,
  41                                         size_t len)
  42 {
  43         u16 auth_alg, auth_transaction, status_code;
  44
  45         if (len < 24 + 6)
  46                 return;
  47
  48         auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
  49         auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
  50         status_code = le16_to_cpu(mgmt->u.auth.status_code);
  51
  52         /*
  53          * IEEE 802.11 standard does not require authentication in IBSS
  54          * networks and most implementations do not seem to use it.
  55          * However, try to reply to authentication attempts if someone
  56          * has actually implemented this.
  57          */
  58         if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
  59                 ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
  60                                     sdata->u.ibss.bssid, NULL, 0, 0);
  61 }
  62
  63 static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
  64                                       const u8 *bssid, const int beacon_int,
  65                                       struct ieee80211_channel *chan,
  66                                       const u32 basic_rates,
  67                                       const u16 capability, u64 tsf)
  68 {
  69         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
  70         struct ieee80211_local *local = sdata->local;
  71         int rates, i;
  72         struct sk_buff *skb;
  73         struct ieee80211_mgmt *mgmt;
  74         u8 *pos;
  75         struct ieee80211_supported_band *sband;
  76         struct cfg80211_bss *bss;
  77         u32 bss_change;
  78         u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
  79
  80         /* Reset own TSF to allow time synchronization work. */
  81         drv_reset_tsf(local);
  82
  83         skb = ifibss->skb;
  84         rcu_assign_pointer(ifibss->presp, NULL);
  85         synchronize_rcu();
  86         skb->data = skb->head;
  87         skb->len = 0;
  88         skb_reset_tail_pointer(skb);
  89         skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
  90
  91         if (memcmp(ifibss->bssid, bssid, ETH_ALEN))
  92                 sta_info_flush(sdata->local, sdata);
  93
  94         /* if merging, indicate to driver that we leave the old IBSS */
  95         if (sdata->vif.bss_conf.ibss_joined) {
  96                 sdata->vif.bss_conf.ibss_joined = false;
  97                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
  98         }
  99
 100         memcpy(ifibss->bssid, bssid, ETH_ALEN);
 101
 102         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 103
 104         local->oper_channel = chan;
 105         WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
 106         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 107
 108         sband = local->hw.wiphy->bands[chan->band];
 109
 110         /* build supported rates array */
 111         pos = supp_rates;
 112         for (i = 0; i < sband->n_bitrates; i++) {
 113                 int rate = sband->bitrates[i].bitrate;
 114                 u8 basic = 0;
 115                 if (basic_rates & BIT(i))
 116                         basic = 0x80;
 117                 *pos++ = basic | (u8) (rate / 5);
 118         }
 119
 120         /* Build IBSS probe response */
 121         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 122         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 123         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 124                                           IEEE80211_STYPE_PROBE_RESP);
 125         memset(mgmt->da, 0xff, ETH_ALEN);
 126         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 127         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 128         mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
 129         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 130         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 131
 132         pos = skb_put(skb, 2 + ifibss->ssid_len);
 133         *pos++ = WLAN_EID_SSID;
 134         *pos++ = ifibss->ssid_len;
 135         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 136
 137         rates = sband->n_bitrates;
 138         if (rates > 8)
 139                 rates = 8;
 140         pos = skb_put(skb, 2 + rates);
 141         *pos++ = WLAN_EID_SUPP_RATES;
 142         *pos++ = rates;
 143         memcpy(pos, supp_rates, rates);
 144
 145         if (sband->band == IEEE80211_BAND_2GHZ) {
 146                 pos = skb_put(skb, 2 + 1);
 147                 *pos++ = WLAN_EID_DS_PARAMS;
 148                 *pos++ = 1;
 149                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 150         }
 151
 152         pos = skb_put(skb, 2 + 2);
 153         *pos++ = WLAN_EID_IBSS_PARAMS;
 154         *pos++ = 2;
 155         /* FIX: set ATIM window based on scan results */
 156         *pos++ = 0;
 157         *pos++ = 0;
 158
 159         if (sband->n_bitrates > 8) {
 160                 rates = sband->n_bitrates - 8;
 161                 pos = skb_put(skb, 2 + rates);
 162                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 163                 *pos++ = rates;
 164                 memcpy(pos, &supp_rates[8], rates);
 165         }
 166
 167         if (ifibss->ie_len)
 168                 memcpy(skb_put(skb, ifibss->ie_len),
 169                        ifibss->ie, ifibss->ie_len);
 170
 171         rcu_assign_pointer(ifibss->presp, skb);
 172
 173         sdata->vif.bss_conf.beacon_int = beacon_int;
 174         bss_change = BSS_CHANGED_BEACON_INT;
 175         bss_change |= ieee80211_reset_erp_info(sdata);
 176         bss_change |= BSS_CHANGED_BSSID;
 177         bss_change |= BSS_CHANGED_BEACON;
 178         bss_change |= BSS_CHANGED_BEACON_ENABLED;
 179         bss_change |= BSS_CHANGED_IBSS;
 180         sdata->vif.bss_conf.ibss_joined = true;
 181         ieee80211_bss_info_change_notify(sdata, bss_change);
 182
 183         ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
 184
 185         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 186         mod_timer(&ifibss->timer,
 187                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 188
 189         bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 190                                         mgmt, skb->len, 0, GFP_KERNEL);
 191         cfg80211_put_bss(bss);
 192         cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
 193 }
 194
 195 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 196                                     struct ieee80211_bss *bss)
 197 {
 198         struct cfg80211_bss *cbss =
 199                 container_of((void *)bss, struct cfg80211_bss, priv);
 200         struct ieee80211_supported_band *sband;
 201         u32 basic_rates;
 202         int i, j;
 203         u16 beacon_int = cbss->beacon_interval;
 204
 205         if (beacon_int < 10)
 206                 beacon_int = 10;
 207
 208         sband = sdata->local->hw.wiphy->bands[cbss->channel->band];
 209
 210         basic_rates = 0;
 211
 212         for (i = 0; i < bss->supp_rates_len; i++) {
 213                 int rate = (bss->supp_rates[i] & 0x7f) * 5;
 214                 bool is_basic = !!(bss->supp_rates[i] & 0x80);
 215
 216                 for (j = 0; j < sband->n_bitrates; j++) {
 217                         if (sband->bitrates[j].bitrate == rate) {
 218                                 if (is_basic)
 219                                         basic_rates |= BIT(j);
 220                                 break;
 221                         }
 222                 }
 223         }
 224
 225         __ieee80211_sta_join_ibss(sdata, cbss->bssid,
 226                                   beacon_int,
 227                                   cbss->channel,
 228                                   basic_rates,
 229                                   cbss->capability,
 230                                   cbss->tsf);
 231 }
 232
 233 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 234                                   struct ieee80211_mgmt *mgmt,
 235                                   size_t len,
 236                                   struct ieee80211_rx_status *rx_status,
 237                                   struct ieee802_11_elems *elems,
 238                                   bool beacon)
 239 {
 240         struct ieee80211_local *local = sdata->local;
 241         int freq;
 242         struct cfg80211_bss *cbss;
 243         struct ieee80211_bss *bss;
 244         struct sta_info *sta;
 245         struct ieee80211_channel *channel;
 246         u64 beacon_timestamp, rx_timestamp;
 247         u32 supp_rates = 0;
 248         enum ieee80211_band band = rx_status->band;
 249
 250         if (elems->ds_params && elems->ds_params_len == 1)
 251                 freq = ieee80211_channel_to_frequency(elems->ds_params[0]);
 252         else
 253                 freq = rx_status->freq;
 254
 255         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 256
 257         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 258                 return;
 259
 260         if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
 261             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 262                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 263
 264                 rcu_read_lock();
 265
 266                 sta = sta_info_get(sdata, mgmt->sa);
 267                 if (sta) {
 268                         u32 prev_rates;
 269
 270                         prev_rates = sta->sta.supp_rates[band];
 271                         /* make sure mandatory rates are always added */
 272                         sta->sta.supp_rates[band] = supp_rates |
 273                                 ieee80211_mandatory_rates(local, band);
 274
 275                         if (sta->sta.supp_rates[band] != prev_rates) {
 276 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 277                                 printk(KERN_DEBUG "%s: updated supp_rates set "
 278                                     "for %pM based on beacon/probe_response "
 279                                     "(0x%x -> 0x%x)\n",
 280                                     sdata->name, sta->sta.addr,
 281                                     prev_rates, sta->sta.supp_rates[band]);
 282 #endif
 283                                 rate_control_rate_init(sta);
 284                         }
 285                         rcu_read_unlock();
 286                 } else {
 287                         rcu_read_unlock();
 288                         ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 289                                                supp_rates, GFP_KERNEL);
 290                 }
 291         }
 292
 293         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 294                                         channel, beacon);
 295         if (!bss)
 296                 return;
 297
 298         cbss = container_of((void *)bss, struct cfg80211_bss, priv);
 299
 300         /* was just updated in ieee80211_bss_info_update */
 301         beacon_timestamp = cbss->tsf;
 302
 303         /* check if we need to merge IBSS */
 304
 305         /* we use a fixed BSSID */
 306         if (sdata->u.ibss.fixed_bssid)
 307                 goto put_bss;
 308
 309         /* not an IBSS */
 310         if (!(cbss->capability & WLAN_CAPABILITY_IBSS))
 311                 goto put_bss;
 312
 313         /* different channel */
 314         if (cbss->channel != local->oper_channel)
 315                 goto put_bss;
 316
 317         /* different SSID */
 318         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 319             memcmp(elems->ssid, sdata->u.ibss.ssid,
 320                                 sdata->u.ibss.ssid_len))
 321                 goto put_bss;
 322
 323         /* same BSSID */
 324         if (memcmp(cbss->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 325                 goto put_bss;
 326
 327         if (rx_status->flag & RX_FLAG_TSFT) {
 328                 /*
 329                  * For correct IBSS merging we need mactime; since mactime is
 330                  * defined as the time the first data symbol of the frame hits
 331                  * the PHY, and the timestamp of the beacon is defined as "the
 332                  * time that the data symbol containing the first bit of the
 333                  * timestamp is transmitted to the PHY plus the transmitting
 334                  * STA's delays through its local PHY from the MAC-PHY
 335                  * interface to its interface with the WM" (802.11 11.1.2)
 336                  * - equals the time this bit arrives at the receiver - we have
 337                  * to take into account the offset between the two.
 338                  *
 339                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 340                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 341                  */
 342                 int rate;
 343
 344                 if (rx_status->flag & RX_FLAG_HT)
 345                         rate = 65; /* TODO: HT rates */
 346                 else
 347                         rate = local->hw.wiphy->bands[band]->
 348                                 bitrates[rx_status->rate_idx].bitrate;
 349
 350                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 351         } else {
 352                 /*
 353                  * second best option: get current TSF
 354                  * (will return -1 if not supported)
 355                  */
 356                 rx_timestamp = drv_get_tsf(local);
 357         }
 358
 359 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 360         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 361                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 362                mgmt->sa, mgmt->bssid,
 363                (unsigned long long)rx_timestamp,
 364                (unsigned long long)beacon_timestamp,
 365                (unsigned long long)(rx_timestamp - beacon_timestamp),
 366                jiffies);
 367 #endif
 368
 369         /* give slow hardware some time to do the TSF sync */
 370         if (rx_timestamp < IEEE80211_IBSS_MERGE_DELAY)
 371                 goto put_bss;
 372
 373         if (beacon_timestamp > rx_timestamp) {
 374 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 375                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 376                        "local TSF - IBSS merge with BSSID %pM\n",
 377                        sdata->name, mgmt->bssid);
 378 #endif
 379                 ieee80211_sta_join_ibss(sdata, bss);
 380                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 381                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 382                                        supp_rates, GFP_KERNEL);
 383         }
 384
 385  put_bss:
 386         ieee80211_rx_bss_put(local, bss);
 387 }
 388
 389 /*
 390  * Add a new IBSS station, will also be called by the RX code when,
 391  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 392  * must be callable in atomic context.
 393  */
 394 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 395                                         u8 *bssid,u8 *addr, u32 supp_rates,
 396                                         gfp_t gfp)
 397 {
 398         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 399         struct ieee80211_local *local = sdata->local;
 400         struct sta_info *sta;
 401         int band = local->hw.conf.channel->band;
 402
 403         /*
 404          * XXX: Consider removing the least recently used entry and
 405          *      allow new one to be added.
 406          */
 407         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 408                 if (net_ratelimit())
 409                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 410                                sdata->name, addr);
 411                 return NULL;
 412         }
 413
 414         if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
 415                 return NULL;
 416
 417         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 418                 return NULL;
 419
 420 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 421         printk(KERN_DEBUG "%s: Adding new IBSS station %pM (dev=%s)\n",
 422                wiphy_name(local->hw.wiphy), addr, sdata->name);
 423 #endif
 424
 425         sta = sta_info_alloc(sdata, addr, gfp);
 426         if (!sta)
 427                 return NULL;
 428
 429         set_sta_flags(sta, WLAN_STA_AUTHORIZED);
 430
 431         /* make sure mandatory rates are always added */
 432         sta->sta.supp_rates[band] = supp_rates |
 433                         ieee80211_mandatory_rates(local, band);
 434
 435         rate_control_rate_init(sta);
 436
 437         /* If it fails, maybe we raced another insertion? */
 438         if (sta_info_insert(sta))
 439                 return sta_info_get(sdata, addr);
 440         return sta;
 441 }
 442
 443 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 444 {
 445         struct ieee80211_local *local = sdata->local;
 446         int active = 0;
 447         struct sta_info *sta;
 448
 449         rcu_read_lock();
 450
 451         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 452                 if (sta->sdata == sdata &&
 453                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 454                                jiffies)) {
 455                         active++;
 456                         break;
 457                 }
 458         }
 459
 460         rcu_read_unlock();
 461
 462         return active;
 463 }
 464
 465 /*
 466  * This function is called with state == IEEE80211_IBSS_MLME_JOINED
 467  */
 468
 469 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 470 {
 471         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 472
 473         mod_timer(&ifibss->timer,
 474                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 475
 476         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 477
 478         if (time_before(jiffies, ifibss->last_scan_completed +
 479                        IEEE80211_IBSS_MERGE_INTERVAL))
 480                 return;
 481
 482         if (ieee80211_sta_active_ibss(sdata))
 483                 return;
 484
 485         if (ifibss->fixed_channel)
 486                 return;
 487
 488         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 489                "IBSS networks with same SSID (merge)\n", sdata->name);
 490
 491         ieee80211_request_internal_scan(sdata,
 492                         ifibss->ssid, ifibss->ssid_len,
 493                         ifibss->fixed_channel ? ifibss->channel : NULL);
 494 }
 495
 496 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 497 {
 498         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 499         struct ieee80211_local *local = sdata->local;
 500         struct ieee80211_supported_band *sband;
 501         u8 bssid[ETH_ALEN];
 502         u16 capability;
 503         int i;
 504
 505         if (ifibss->fixed_bssid) {
 506                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 507         } else {
 508                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 509                  * own MAC address to make sure that devices that do not have proper
 510                  * random number generator get different BSSID. */
 511                 get_random_bytes(bssid, ETH_ALEN);
 512                 for (i = 0; i < ETH_ALEN; i++)
 513                         bssid[i] ^= sdata->vif.addr[i];
 514                 bssid[0] &= ~0x01;
 515                 bssid[0] |= 0x02;
 516         }
 517
 518         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 519                sdata->name, bssid);
 520
 521         sband = local->hw.wiphy->bands[ifibss->channel->band];
 522
 523         capability = WLAN_CAPABILITY_IBSS;
 524
 525         if (ifibss->privacy)
 526                 capability |= WLAN_CAPABILITY_PRIVACY;
 527         else
 528                 sdata->drop_unencrypted = 0;
 529
 530         __ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
 531                                   ifibss->channel, 3, /* first two are basic */
 532                                   capability, 0);
 533 }
 534
 535 /*
 536  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
 537  */
 538
 539 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 540 {
 541         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 542         struct ieee80211_local *local = sdata->local;
 543         struct cfg80211_bss *cbss;
 544         struct ieee80211_channel *chan = NULL;
 545         const u8 *bssid = NULL;
 546         int active_ibss;
 547         u16 capability;
 548
 549         active_ibss = ieee80211_sta_active_ibss(sdata);
 550 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 551         printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
 552                sdata->name, active_ibss);
 553 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 554
 555         if (active_ibss)
 556                 return;
 557
 558         capability = WLAN_CAPABILITY_IBSS;
 559         if (ifibss->privacy)
 560                 capability |= WLAN_CAPABILITY_PRIVACY;
 561         if (ifibss->fixed_bssid)
 562                 bssid = ifibss->bssid;
 563         if (ifibss->fixed_channel)
 564                 chan = ifibss->channel;
 565         if (!is_zero_ether_addr(ifibss->bssid))
 566                 bssid = ifibss->bssid;
 567         cbss = cfg80211_get_bss(local->hw.wiphy, chan, bssid,
 568                                 ifibss->ssid, ifibss->ssid_len,
 569                                 WLAN_CAPABILITY_IBSS | WLAN_CAPABILITY_PRIVACY,
 570                                 capability);
 571
 572         if (cbss) {
 573                 struct ieee80211_bss *bss;
 574
 575                 bss = (void *)cbss->priv;
 576 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 577                 printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
 578                        "%pM\n", cbss->bssid, ifibss->bssid);
 579 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 580
 581                 printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
 582                        " based on configured SSID\n",
 583                        sdata->name, cbss->bssid);
 584
 585                 ieee80211_sta_join_ibss(sdata, bss);
 586                 ieee80211_rx_bss_put(local, bss);
 587                 return;
 588         }
 589
 590 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 591         printk(KERN_DEBUG "   did not try to join ibss\n");
 592 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 593
 594         /* Selected IBSS not found in current scan results - try to scan */
 595         if (time_after(jiffies, ifibss->last_scan_completed +
 596                                         IEEE80211_SCAN_INTERVAL)) {
 597                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
 598                        "join\n", sdata->name);
 599
 600                 ieee80211_request_internal_scan(sdata,
 601                                 ifibss->ssid, ifibss->ssid_len,
 602                                 ifibss->fixed_channel ? ifibss->channel : NULL);
 603         } else {
 604                 int interval = IEEE80211_SCAN_INTERVAL;
 605
 606                 if (time_after(jiffies, ifibss->ibss_join_req +
 607                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 608                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 609                                 ieee80211_sta_create_ibss(sdata);
 610                                 return;
 611                         }
 612                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 613                                " %d MHz\n", sdata->name,
 614                                local->hw.conf.channel->center_freq);
 615
 616                         /* No IBSS found - decrease scan interval and continue
 617                          * scanning. */
 618                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 619                 }
 620
 621                 mod_timer(&ifibss->timer,
 622                           round_jiffies(jiffies + interval));
 623         }
 624 }
 625
 626 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 627                                         struct ieee80211_mgmt *mgmt,
 628                                         size_t len)
 629 {
 630         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 631         struct ieee80211_local *local = sdata->local;
 632         int tx_last_beacon;
 633         struct sk_buff *skb;
 634         struct ieee80211_mgmt *resp;
 635         u8 *pos, *end;
 636
 637         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 638             len < 24 + 2 || !ifibss->presp)
 639                 return;
 640
 641         tx_last_beacon = drv_tx_last_beacon(local);
 642
 643 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 644         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 645                " (tx_last_beacon=%d)\n",
 646                sdata->name, mgmt->sa, mgmt->da,
 647                mgmt->bssid, tx_last_beacon);
 648 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 649
 650         if (!tx_last_beacon)
 651                 return;
 652
 653         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 654             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 655                 return;
 656
 657         end = ((u8 *) mgmt) + len;
 658         pos = mgmt->u.probe_req.variable;
 659         if (pos[0] != WLAN_EID_SSID ||
 660             pos + 2 + pos[1] > end) {
 661 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 662                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 663                        "from %pM\n",
 664                        sdata->name, mgmt->sa);
 665 #endif
 666                 return;
 667         }
 668         if (pos[1] != 0 &&
 669             (pos[1] != ifibss->ssid_len ||
 670              memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 671                 /* Ignore ProbeReq for foreign SSID */
 672                 return;
 673         }
 674
 675         /* Reply with ProbeResp */
 676         skb = skb_copy(ifibss->presp, GFP_KERNEL);
 677         if (!skb)
 678                 return;
 679
 680         resp = (struct ieee80211_mgmt *) skb->data;
 681         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 682 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 683         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 684                sdata->name, resp->da);
 685 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 686         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 687         ieee80211_tx_skb(sdata, skb);
 688 }
 689
 690 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 691                                          struct ieee80211_mgmt *mgmt,
 692                                          size_t len,
 693                                          struct ieee80211_rx_status *rx_status)
 694 {
 695         size_t baselen;
 696         struct ieee802_11_elems elems;
 697
 698         if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 699                 return; /* ignore ProbeResp to foreign address */
 700
 701         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 702         if (baselen > len)
 703                 return;
 704
 705         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 706                                 &elems);
 707
 708         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 709 }
 710
 711 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 712                                      struct ieee80211_mgmt *mgmt,
 713                                      size_t len,
 714                                      struct ieee80211_rx_status *rx_status)
 715 {
 716         size_t baselen;
 717         struct ieee802_11_elems elems;
 718
 719         /* Process beacon from the current BSS */
 720         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 721         if (baselen > len)
 722                 return;
 723
 724         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 725
 726         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 727 }
 728
 729 static void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 730                                           struct sk_buff *skb)
 731 {
 732         struct ieee80211_rx_status *rx_status;
 733         struct ieee80211_mgmt *mgmt;
 734         u16 fc;
 735
 736         rx_status = IEEE80211_SKB_RXCB(skb);
 737         mgmt = (struct ieee80211_mgmt *) skb->data;
 738         fc = le16_to_cpu(mgmt->frame_control);
 739
 740         switch (fc & IEEE80211_FCTL_STYPE) {
 741         case IEEE80211_STYPE_PROBE_REQ:
 742                 ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
 743                 break;
 744         case IEEE80211_STYPE_PROBE_RESP:
 745                 ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
 746                                              rx_status);
 747                 break;
 748         case IEEE80211_STYPE_BEACON:
 749                 ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
 750                                          rx_status);
 751                 break;
 752         case IEEE80211_STYPE_AUTH:
 753                 ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
 754                 break;
 755         }
 756
 757         kfree_skb(skb);
 758 }
 759
 760 static void ieee80211_ibss_work(struct work_struct *work)
 761 {
 762         struct ieee80211_sub_if_data *sdata =
 763                 container_of(work, struct ieee80211_sub_if_data, u.ibss.work);
 764         struct ieee80211_local *local = sdata->local;
 765         struct ieee80211_if_ibss *ifibss;
 766         struct sk_buff *skb;
 767
 768         if (WARN_ON(local->suspended))
 769                 return;
 770
 771         if (!ieee80211_sdata_running(sdata))
 772                 return;
 773
 774         if (local->scanning)
 775                 return;
 776
 777         if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_ADHOC))
 778                 return;
 779         ifibss = &sdata->u.ibss;
 780
 781         while ((skb = skb_dequeue(&ifibss->skb_queue)))
 782                 ieee80211_ibss_rx_queued_mgmt(sdata, skb);
 783
 784         if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
 785                 return;
 786
 787         switch (ifibss->state) {
 788         case IEEE80211_IBSS_MLME_SEARCH:
 789                 ieee80211_sta_find_ibss(sdata);
 790                 break;
 791         case IEEE80211_IBSS_MLME_JOINED:
 792                 ieee80211_sta_merge_ibss(sdata);
 793                 break;
 794         default:
 795                 WARN_ON(1);
 796                 break;
 797         }
 798 }
 799
 800 static void ieee80211_ibss_timer(unsigned long data)
 801 {
 802         struct ieee80211_sub_if_data *sdata =
 803                 (struct ieee80211_sub_if_data *) data;
 804         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 805         struct ieee80211_local *local = sdata->local;
 806
 807         if (local->quiescing) {
 808                 ifibss->timer_running = true;
 809                 return;
 810         }
 811
 812         set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
 813         ieee80211_queue_work(&local->hw, &ifibss->work);
 814 }
 815
 816 #ifdef CONFIG_PM
 817 void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
 818 {
 819         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 820
 821         cancel_work_sync(&ifibss->work);
 822         if (del_timer_sync(&ifibss->timer))
 823                 ifibss->timer_running = true;
 824 }
 825
 826 void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
 827 {
 828         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 829
 830         if (ifibss->timer_running) {
 831                 add_timer(&ifibss->timer);
 832                 ifibss->timer_running = false;
 833         }
 834 }
 835 #endif
 836
 837 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 838 {
 839         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 840
 841         INIT_WORK(&ifibss->work, ieee80211_ibss_work);
 842         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 843                     (unsigned long) sdata);
 844         skb_queue_head_init(&ifibss->skb_queue);
 845 }
 846
 847 /* scan finished notification */
 848 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 849 {
 850         struct ieee80211_sub_if_data *sdata;
 851
 852         mutex_lock(&local->iflist_mtx);
 853         list_for_each_entry(sdata, &local->interfaces, list) {
 854                 if (!ieee80211_sdata_running(sdata))
 855                         continue;
 856                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 857                         continue;
 858                 if (!sdata->u.ibss.ssid_len)
 859                         continue;
 860                 sdata->u.ibss.last_scan_completed = jiffies;
 861                 mod_timer(&sdata->u.ibss.timer, 0);
 862         }
 863         mutex_unlock(&local->iflist_mtx);
 864 }
 865
 866 ieee80211_rx_result
 867 ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb)
 868 {
 869         struct ieee80211_local *local = sdata->local;
 870         struct ieee80211_mgmt *mgmt;
 871         u16 fc;
 872
 873         if (skb->len < 24)
 874                 return RX_DROP_MONITOR;
 875
 876         mgmt = (struct ieee80211_mgmt *) skb->data;
 877         fc = le16_to_cpu(mgmt->frame_control);
 878
 879         switch (fc & IEEE80211_FCTL_STYPE) {
 880         case IEEE80211_STYPE_PROBE_RESP:
 881         case IEEE80211_STYPE_BEACON:
 882         case IEEE80211_STYPE_PROBE_REQ:
 883         case IEEE80211_STYPE_AUTH:
 884                 skb_queue_tail(&sdata->u.ibss.skb_queue, skb);
 885                 ieee80211_queue_work(&local->hw, &sdata->u.ibss.work);
 886                 return RX_QUEUED;
 887         }
 888
 889         return RX_DROP_MONITOR;
 890 }
 891
 892 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 893                         struct cfg80211_ibss_params *params)
 894 {
 895         struct sk_buff *skb;
 896
 897         if (params->bssid) {
 898                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 899                 sdata->u.ibss.fixed_bssid = true;
 900         } else
 901                 sdata->u.ibss.fixed_bssid = false;
 902
 903         sdata->u.ibss.privacy = params->privacy;
 904
 905         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 906
 907         sdata->u.ibss.channel = params->channel;
 908         sdata->u.ibss.fixed_channel = params->channel_fixed;
 909
 910         /* fix ourselves to that channel now already */
 911         if (params->channel_fixed) {
 912                 sdata->local->oper_channel = params->channel;
 913                 WARN_ON(!ieee80211_set_channel_type(sdata->local, sdata,
 914                                                     NL80211_CHAN_NO_HT));
 915         }
 916
 917         if (params->ie) {
 918                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 919                                            GFP_KERNEL);
 920                 if (sdata->u.ibss.ie)
 921                         sdata->u.ibss.ie_len = params->ie_len;
 922         }
 923
 924         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 925                             36 /* bitrates */ +
 926                             34 /* SSID */ +
 927                             3  /* DS params */ +
 928                             4  /* IBSS params */ +
 929                             params->ie_len);
 930         if (!skb)
 931                 return -ENOMEM;
 932
 933         sdata->u.ibss.skb = skb;
 934         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 935         sdata->u.ibss.ibss_join_req = jiffies;
 936
 937         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 938
 939         /*
 940          * The ssid_len setting below is used to see whether
 941          * we are active, and we need all other settings
 942          * before that may get visible.
 943          */
 944         mb();
 945
 946         sdata->u.ibss.ssid_len = params->ssid_len;
 947
 948         ieee80211_recalc_idle(sdata->local);
 949
 950         set_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 951         ieee80211_queue_work(&sdata->local->hw, &sdata->u.ibss.work);
 952
 953         return 0;
 954 }
 955
 956 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 957 {
 958         struct sk_buff *skb;
 959
 960         del_timer_sync(&sdata->u.ibss.timer);
 961         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 962         cancel_work_sync(&sdata->u.ibss.work);
 963         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 964
 965         sta_info_flush(sdata->local, sdata);
 966
 967         /* remove beacon */
 968         kfree(sdata->u.ibss.ie);
 969         skb = sdata->u.ibss.presp;
 970         rcu_assign_pointer(sdata->u.ibss.presp, NULL);
 971         sdata->vif.bss_conf.ibss_joined = false;
 972         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
 973                                                 BSS_CHANGED_IBSS);
 974         synchronize_rcu();
 975         kfree_skb(skb);
 976
 977         skb_queue_purge(&sdata->u.ibss.skb_queue);
 978         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
 979         sdata->u.ibss.ssid_len = 0;
 980
 981         ieee80211_recalc_idle(sdata->local);
 982
 983         return 0;
 984 }