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 "rate.h"
  26
  27 #define IEEE80211_SCAN_INTERVAL (2 * HZ)
  28 #define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
  29 #define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)
  30
  31 #define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
  32 #define IEEE80211_IBSS_MERGE_DELAY 0x400000
  33 #define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
  34
  35 #define IEEE80211_IBSS_MAX_STA_ENTRIES 128
  36
  37
  38 static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
  39                                         struct ieee80211_mgmt *mgmt,
  40                                         size_t len)
  41 {
  42         u16 auth_alg, auth_transaction, status_code;
  43
  44         if (len < 24 + 6)
  45                 return;
  46
  47         auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
  48         auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
  49         status_code = le16_to_cpu(mgmt->u.auth.status_code);
  50
  51         /*
  52          * IEEE 802.11 standard does not require authentication in IBSS
  53          * networks and most implementations do not seem to use it.
  54          * However, try to reply to authentication attempts if someone
  55          * has actually implemented this.
  56          */
  57         if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
  58                 ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
  59                                     sdata->u.ibss.bssid, 0);
  60 }
  61
  62 static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
  63                                       const u8 *bssid, const int beacon_int,
  64                                       struct ieee80211_channel *chan,
  65                                       const size_t supp_rates_len,
  66                                       const u8 *supp_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, j;
  72         struct sk_buff *skb;
  73         struct ieee80211_mgmt *mgmt;
  74         u8 *pos;
  75         struct ieee80211_supported_band *sband;
  76         u32 bss_change;
  77
  78         if (local->ops->reset_tsf) {
  79                 /* Reset own TSF to allow time synchronization work. */
  80                 local->ops->reset_tsf(local_to_hw(local));
  81         }
  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         memcpy(ifibss->bssid, bssid, ETH_ALEN);
  95
  96         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
  97
  98         ieee80211_if_config(sdata, IEEE80211_IFCC_BSSID);
  99
 100         local->oper_channel = chan;
 101         local->oper_channel_type = NL80211_CHAN_NO_HT;
 102         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 103
 104         sdata->vif.bss_conf.beacon_int = beacon_int;
 105         bss_change = BSS_CHANGED_BEACON_INT;
 106         bss_change |= ieee80211_reset_erp_info(sdata);
 107         ieee80211_bss_info_change_notify(sdata, bss_change);
 108
 109         sband = local->hw.wiphy->bands[chan->band];
 110
 111         /* Build IBSS probe response */
 112         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 113         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 114         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 115                                           IEEE80211_STYPE_PROBE_RESP);
 116         memset(mgmt->da, 0xff, ETH_ALEN);
 117         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 118         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 119         mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
 120         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 121         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 122
 123         pos = skb_put(skb, 2 + ifibss->ssid_len);
 124         *pos++ = WLAN_EID_SSID;
 125         *pos++ = ifibss->ssid_len;
 126         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 127
 128         rates = supp_rates_len;
 129         if (rates > 8)
 130                 rates = 8;
 131         pos = skb_put(skb, 2 + rates);
 132         *pos++ = WLAN_EID_SUPP_RATES;
 133         *pos++ = rates;
 134         memcpy(pos, supp_rates, rates);
 135
 136         if (sband->band == IEEE80211_BAND_2GHZ) {
 137                 pos = skb_put(skb, 2 + 1);
 138                 *pos++ = WLAN_EID_DS_PARAMS;
 139                 *pos++ = 1;
 140                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 141         }
 142
 143         pos = skb_put(skb, 2 + 2);
 144         *pos++ = WLAN_EID_IBSS_PARAMS;
 145         *pos++ = 2;
 146         /* FIX: set ATIM window based on scan results */
 147         *pos++ = 0;
 148         *pos++ = 0;
 149
 150         if (supp_rates_len > 8) {
 151                 rates = supp_rates_len - 8;
 152                 pos = skb_put(skb, 2 + rates);
 153                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 154                 *pos++ = rates;
 155                 memcpy(pos, &supp_rates[8], rates);
 156         }
 157
 158         if (ifibss->ie_len)
 159                 memcpy(skb_put(skb, ifibss->ie_len),
 160                        ifibss->ie, ifibss->ie_len);
 161
 162         rcu_assign_pointer(ifibss->presp, skb);
 163
 164         ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON |
 165                                    IEEE80211_IFCC_BEACON_ENABLED);
 166
 167         rates = 0;
 168         for (i = 0; i < supp_rates_len; i++) {
 169                 int bitrate = (supp_rates[i] & 0x7f) * 5;
 170                 for (j = 0; j < sband->n_bitrates; j++)
 171                         if (sband->bitrates[j].bitrate == bitrate)
 172                                 rates |= BIT(j);
 173         }
 174
 175         ieee80211_sta_def_wmm_params(sdata, supp_rates_len, supp_rates);
 176
 177         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 178         mod_timer(&ifibss->timer,
 179                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 180
 181         cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 182                                   mgmt, skb->len, 0, GFP_KERNEL);
 183         cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
 184 }
 185
 186 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 187                                     struct ieee80211_bss *bss)
 188 {
 189         u16 beacon_int = bss->cbss.beacon_interval;
 190
 191         if (beacon_int < 10)
 192                 beacon_int = 10;
 193
 194         __ieee80211_sta_join_ibss(sdata, bss->cbss.bssid,
 195                                   beacon_int,
 196                                   bss->cbss.channel,
 197                                   bss->supp_rates_len, bss->supp_rates,
 198                                   bss->cbss.capability,
 199                                   bss->cbss.tsf);
 200 }
 201
 202 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 203                                   struct ieee80211_mgmt *mgmt,
 204                                   size_t len,
 205                                   struct ieee80211_rx_status *rx_status,
 206                                   struct ieee802_11_elems *elems,
 207                                   bool beacon)
 208 {
 209         struct ieee80211_local *local = sdata->local;
 210         int freq;
 211         struct ieee80211_bss *bss;
 212         struct sta_info *sta;
 213         struct ieee80211_channel *channel;
 214         u64 beacon_timestamp, rx_timestamp;
 215         u32 supp_rates = 0;
 216         enum ieee80211_band band = rx_status->band;
 217
 218         if (elems->ds_params && elems->ds_params_len == 1)
 219                 freq = ieee80211_channel_to_frequency(elems->ds_params[0]);
 220         else
 221                 freq = rx_status->freq;
 222
 223         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 224
 225         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 226                 return;
 227
 228         if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
 229             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 230                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 231
 232                 rcu_read_lock();
 233
 234                 sta = sta_info_get(local, mgmt->sa);
 235                 if (sta) {
 236                         u32 prev_rates;
 237
 238                         prev_rates = sta->sta.supp_rates[band];
 239                         /* make sure mandatory rates are always added */
 240                         sta->sta.supp_rates[band] = supp_rates |
 241                                 ieee80211_mandatory_rates(local, band);
 242
 243 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 244                         if (sta->sta.supp_rates[band] != prev_rates)
 245                                 printk(KERN_DEBUG "%s: updated supp_rates set "
 246                                     "for %pM based on beacon info (0x%llx | "
 247                                     "0x%llx -> 0x%llx)\n",
 248                                     sdata->dev->name,
 249                                     sta->sta.addr,
 250                                     (unsigned long long) prev_rates,
 251                                     (unsigned long long) supp_rates,
 252                                     (unsigned long long) sta->sta.supp_rates[band]);
 253 #endif
 254                 } else
 255                         ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
 256
 257                 rcu_read_unlock();
 258         }
 259
 260         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 261                                         channel, beacon);
 262         if (!bss)
 263                 return;
 264
 265         /* was just updated in ieee80211_bss_info_update */
 266         beacon_timestamp = bss->cbss.tsf;
 267
 268         /* check if we need to merge IBSS */
 269
 270         /* merge only on beacons (???) */
 271         if (!beacon)
 272                 goto put_bss;
 273
 274         /* we use a fixed BSSID */
 275         if (sdata->u.ibss.bssid)
 276                 goto put_bss;
 277
 278         /* not an IBSS */
 279         if (!(bss->cbss.capability & WLAN_CAPABILITY_IBSS))
 280                 goto put_bss;
 281
 282         /* different channel */
 283         if (bss->cbss.channel != local->oper_channel)
 284                 goto put_bss;
 285
 286         /* different SSID */
 287         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 288             memcmp(elems->ssid, sdata->u.ibss.ssid,
 289                                 sdata->u.ibss.ssid_len))
 290                 goto put_bss;
 291
 292         /* same BSSID */
 293         if (memcmp(bss->cbss.bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 294                 goto put_bss;
 295
 296         if (rx_status->flag & RX_FLAG_TSFT) {
 297                 /*
 298                  * For correct IBSS merging we need mactime; since mactime is
 299                  * defined as the time the first data symbol of the frame hits
 300                  * the PHY, and the timestamp of the beacon is defined as "the
 301                  * time that the data symbol containing the first bit of the
 302                  * timestamp is transmitted to the PHY plus the transmitting
 303                  * STA's delays through its local PHY from the MAC-PHY
 304                  * interface to its interface with the WM" (802.11 11.1.2)
 305                  * - equals the time this bit arrives at the receiver - we have
 306                  * to take into account the offset between the two.
 307                  *
 308                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 309                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 310                  */
 311                 int rate;
 312
 313                 if (rx_status->flag & RX_FLAG_HT)
 314                         rate = 65; /* TODO: HT rates */
 315                 else
 316                         rate = local->hw.wiphy->bands[band]->
 317                                 bitrates[rx_status->rate_idx].bitrate;
 318
 319                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 320         } else if (local && local->ops && local->ops->get_tsf)
 321                 /* second best option: get current TSF */
 322                 rx_timestamp = local->ops->get_tsf(local_to_hw(local));
 323         else
 324                 /* can't merge without knowing the TSF */
 325                 rx_timestamp = -1LLU;
 326
 327 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 328         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 329                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 330                mgmt->sa, mgmt->bssid,
 331                (unsigned long long)rx_timestamp,
 332                (unsigned long long)beacon_timestamp,
 333                (unsigned long long)(rx_timestamp - beacon_timestamp),
 334                jiffies);
 335 #endif
 336
 337         /* give slow hardware some time to do the TSF sync */
 338         if (rx_timestamp < IEEE80211_IBSS_MERGE_DELAY)
 339                 goto put_bss;
 340
 341         if (beacon_timestamp > rx_timestamp) {
 342 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 343                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 344                        "local TSF - IBSS merge with BSSID %pM\n",
 345                        sdata->dev->name, mgmt->bssid);
 346 #endif
 347                 ieee80211_sta_join_ibss(sdata, bss);
 348                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
 349         }
 350
 351  put_bss:
 352         ieee80211_rx_bss_put(local, bss);
 353 }
 354
 355 /*
 356  * Add a new IBSS station, will also be called by the RX code when,
 357  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 358  * must be callable in atomic context.
 359  */
 360 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 361                                         u8 *bssid,u8 *addr, u32 supp_rates)
 362 {
 363         struct ieee80211_local *local = sdata->local;
 364         struct sta_info *sta;
 365         int band = local->hw.conf.channel->band;
 366
 367         /*
 368          * XXX: Consider removing the least recently used entry and
 369          *      allow new one to be added.
 370          */
 371         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 372                 if (net_ratelimit())
 373                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 374                                sdata->dev->name, addr);
 375                 return NULL;
 376         }
 377
 378         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 379                 return NULL;
 380
 381 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 382         printk(KERN_DEBUG "%s: Adding new IBSS station %pM (dev=%s)\n",
 383                wiphy_name(local->hw.wiphy), addr, sdata->dev->name);
 384 #endif
 385
 386         sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
 387         if (!sta)
 388                 return NULL;
 389
 390         set_sta_flags(sta, WLAN_STA_AUTHORIZED);
 391
 392         /* make sure mandatory rates are always added */
 393         sta->sta.supp_rates[band] = supp_rates |
 394                         ieee80211_mandatory_rates(local, band);
 395
 396         rate_control_rate_init(sta);
 397
 398         if (sta_info_insert(sta))
 399                 return NULL;
 400
 401         return sta;
 402 }
 403
 404 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 405 {
 406         struct ieee80211_local *local = sdata->local;
 407         int active = 0;
 408         struct sta_info *sta;
 409
 410         rcu_read_lock();
 411
 412         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 413                 if (sta->sdata == sdata &&
 414                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 415                                jiffies)) {
 416                         active++;
 417                         break;
 418                 }
 419         }
 420
 421         rcu_read_unlock();
 422
 423         return active;
 424 }
 425
 426
 427 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 428 {
 429         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 430
 431         mod_timer(&ifibss->timer,
 432                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 433
 434         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 435
 436         if (ieee80211_sta_active_ibss(sdata))
 437                 return;
 438
 439         if (ifibss->fixed_channel)
 440                 return;
 441
 442         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 443                "IBSS networks with same SSID (merge)\n", sdata->dev->name);
 444
 445         ieee80211_request_internal_scan(sdata, ifibss->ssid, ifibss->ssid_len);
 446 }
 447
 448 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 449 {
 450         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 451         struct ieee80211_local *local = sdata->local;
 452         struct ieee80211_supported_band *sband;
 453         u8 *pos;
 454         u8 bssid[ETH_ALEN];
 455         u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
 456         u16 capability;
 457         int i;
 458
 459         if (ifibss->fixed_bssid) {
 460                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 461         } else {
 462                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 463                  * own MAC address to make sure that devices that do not have proper
 464                  * random number generator get different BSSID. */
 465                 get_random_bytes(bssid, ETH_ALEN);
 466                 for (i = 0; i < ETH_ALEN; i++)
 467                         bssid[i] ^= sdata->dev->dev_addr[i];
 468                 bssid[0] &= ~0x01;
 469                 bssid[0] |= 0x02;
 470         }
 471
 472         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 473                sdata->dev->name, bssid);
 474
 475         sband = local->hw.wiphy->bands[ifibss->channel->band];
 476
 477         capability = WLAN_CAPABILITY_IBSS;
 478
 479         if (sdata->default_key)
 480                 capability |= WLAN_CAPABILITY_PRIVACY;
 481         else
 482                 sdata->drop_unencrypted = 0;
 483
 484         pos = supp_rates;
 485         for (i = 0; i < sband->n_bitrates; i++) {
 486                 int rate = sband->bitrates[i].bitrate;
 487                 *pos++ = (u8) (rate / 5);
 488         }
 489
 490         __ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
 491                                   ifibss->channel, sband->n_bitrates,
 492                                   supp_rates, capability, 0);
 493 }
 494
 495 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 496 {
 497         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 498         struct ieee80211_local *local = sdata->local;
 499         struct ieee80211_bss *bss;
 500         struct ieee80211_channel *chan = NULL;
 501         const u8 *bssid = NULL;
 502         int active_ibss;
 503
 504         active_ibss = ieee80211_sta_active_ibss(sdata);
 505 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 506         printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
 507                sdata->dev->name, active_ibss);
 508 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 509
 510         if (active_ibss)
 511                 return;
 512
 513         if (ifibss->fixed_bssid)
 514                 bssid = ifibss->bssid;
 515         if (ifibss->fixed_channel)
 516                 chan = ifibss->channel;
 517         if (!is_zero_ether_addr(ifibss->bssid))
 518                 bssid = ifibss->bssid;
 519         bss = (void *)cfg80211_get_bss(local->hw.wiphy, chan, bssid,
 520                                        ifibss->ssid, ifibss->ssid_len,
 521                                        WLAN_CAPABILITY_IBSS,
 522                                        WLAN_CAPABILITY_IBSS);
 523
 524 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 525         if (bss)
 526                 printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
 527                        "%pM\n", bss->cbss.bssid, ifibss->bssid);
 528 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 529
 530         if (bss && memcmp(ifibss->bssid, bss->cbss.bssid, ETH_ALEN)) {
 531                 printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
 532                        " based on configured SSID\n",
 533                        sdata->dev->name, bss->cbss.bssid);
 534
 535                 ieee80211_sta_join_ibss(sdata, bss);
 536                 ieee80211_rx_bss_put(local, bss);
 537                 return;
 538         } else if (bss)
 539                 ieee80211_rx_bss_put(local, bss);
 540
 541 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 542         printk(KERN_DEBUG "   did not try to join ibss\n");
 543 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 544
 545         /* Selected IBSS not found in current scan results - try to scan */
 546         if (ifibss->state == IEEE80211_IBSS_MLME_JOINED &&
 547             !ieee80211_sta_active_ibss(sdata)) {
 548                 mod_timer(&ifibss->timer,
 549                           round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 550         } else if (time_after(jiffies, ifibss->last_scan_completed +
 551                                         IEEE80211_SCAN_INTERVAL)) {
 552                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
 553                        "join\n", sdata->dev->name);
 554
 555                 ieee80211_request_internal_scan(sdata, ifibss->ssid,
 556                                                 ifibss->ssid_len);
 557         } else if (ifibss->state != IEEE80211_IBSS_MLME_JOINED) {
 558                 int interval = IEEE80211_SCAN_INTERVAL;
 559
 560                 if (time_after(jiffies, ifibss->ibss_join_req +
 561                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 562                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 563                                 ieee80211_sta_create_ibss(sdata);
 564                                 return;
 565                         }
 566                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 567                                " %d MHz\n", sdata->dev->name,
 568                                local->hw.conf.channel->center_freq);
 569
 570                         /* No IBSS found - decrease scan interval and continue
 571                          * scanning. */
 572                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 573                 }
 574
 575                 ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
 576                 mod_timer(&ifibss->timer,
 577                           round_jiffies(jiffies + interval));
 578         }
 579 }
 580
 581 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 582                                         struct ieee80211_mgmt *mgmt,
 583                                         size_t len)
 584 {
 585         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 586         struct ieee80211_local *local = sdata->local;
 587         int tx_last_beacon;
 588         struct sk_buff *skb;
 589         struct ieee80211_mgmt *resp;
 590         u8 *pos, *end;
 591
 592         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 593             len < 24 + 2 || !ifibss->presp)
 594                 return;
 595
 596         if (local->ops->tx_last_beacon)
 597                 tx_last_beacon = local->ops->tx_last_beacon(local_to_hw(local));
 598         else
 599                 tx_last_beacon = 1;
 600
 601 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 602         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 603                " (tx_last_beacon=%d)\n",
 604                sdata->dev->name, mgmt->sa, mgmt->da,
 605                mgmt->bssid, tx_last_beacon);
 606 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 607
 608         if (!tx_last_beacon)
 609                 return;
 610
 611         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 612             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 613                 return;
 614
 615         end = ((u8 *) mgmt) + len;
 616         pos = mgmt->u.probe_req.variable;
 617         if (pos[0] != WLAN_EID_SSID ||
 618             pos + 2 + pos[1] > end) {
 619 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 620                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 621                        "from %pM\n",
 622                        sdata->dev->name, mgmt->sa);
 623 #endif
 624                 return;
 625         }
 626         if (pos[1] != 0 &&
 627             (pos[1] != ifibss->ssid_len ||
 628              !memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 629                 /* Ignore ProbeReq for foreign SSID */
 630                 return;
 631         }
 632
 633         /* Reply with ProbeResp */
 634         skb = skb_copy(ifibss->presp, GFP_KERNEL);
 635         if (!skb)
 636                 return;
 637
 638         resp = (struct ieee80211_mgmt *) skb->data;
 639         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 640 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 641         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 642                sdata->dev->name, resp->da);
 643 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 644         ieee80211_tx_skb(sdata, skb, 0);
 645 }
 646
 647 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 648                                          struct ieee80211_mgmt *mgmt,
 649                                          size_t len,
 650                                          struct ieee80211_rx_status *rx_status)
 651 {
 652         size_t baselen;
 653         struct ieee802_11_elems elems;
 654
 655         if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
 656                 return; /* ignore ProbeResp to foreign address */
 657
 658         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 659         if (baselen > len)
 660                 return;
 661
 662         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 663                                 &elems);
 664
 665         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 666 }
 667
 668 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 669                                      struct ieee80211_mgmt *mgmt,
 670                                      size_t len,
 671                                      struct ieee80211_rx_status *rx_status)
 672 {
 673         size_t baselen;
 674         struct ieee802_11_elems elems;
 675
 676         /* Process beacon from the current BSS */
 677         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 678         if (baselen > len)
 679                 return;
 680
 681         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 682
 683         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 684 }
 685
 686 static void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 687                                           struct sk_buff *skb)
 688 {
 689         struct ieee80211_rx_status *rx_status;
 690         struct ieee80211_mgmt *mgmt;
 691         u16 fc;
 692
 693         rx_status = (struct ieee80211_rx_status *) skb->cb;
 694         mgmt = (struct ieee80211_mgmt *) skb->data;
 695         fc = le16_to_cpu(mgmt->frame_control);
 696
 697         switch (fc & IEEE80211_FCTL_STYPE) {
 698         case IEEE80211_STYPE_PROBE_REQ:
 699                 ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
 700                 break;
 701         case IEEE80211_STYPE_PROBE_RESP:
 702                 ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
 703                                              rx_status);
 704                 break;
 705         case IEEE80211_STYPE_BEACON:
 706                 ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
 707                                          rx_status);
 708                 break;
 709         case IEEE80211_STYPE_AUTH:
 710                 ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
 711                 break;
 712         }
 713
 714         kfree_skb(skb);
 715 }
 716
 717 static void ieee80211_ibss_work(struct work_struct *work)
 718 {
 719         struct ieee80211_sub_if_data *sdata =
 720                 container_of(work, struct ieee80211_sub_if_data, u.ibss.work);
 721         struct ieee80211_local *local = sdata->local;
 722         struct ieee80211_if_ibss *ifibss;
 723         struct sk_buff *skb;
 724
 725         if (!netif_running(sdata->dev))
 726                 return;
 727
 728         if (local->sw_scanning || local->hw_scanning)
 729                 return;
 730
 731         if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_ADHOC))
 732                 return;
 733         ifibss = &sdata->u.ibss;
 734
 735         while ((skb = skb_dequeue(&ifibss->skb_queue)))
 736                 ieee80211_ibss_rx_queued_mgmt(sdata, skb);
 737
 738         if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
 739                 return;
 740
 741         switch (ifibss->state) {
 742         case IEEE80211_IBSS_MLME_SEARCH:
 743                 ieee80211_sta_find_ibss(sdata);
 744                 break;
 745         case IEEE80211_IBSS_MLME_JOINED:
 746                 ieee80211_sta_merge_ibss(sdata);
 747                 break;
 748         default:
 749                 WARN_ON(1);
 750                 break;
 751         }
 752 }
 753
 754 static void ieee80211_ibss_timer(unsigned long data)
 755 {
 756         struct ieee80211_sub_if_data *sdata =
 757                 (struct ieee80211_sub_if_data *) data;
 758         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 759         struct ieee80211_local *local = sdata->local;
 760
 761         set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
 762         queue_work(local->hw.workqueue, &ifibss->work);
 763 }
 764
 765 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 766 {
 767         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 768
 769         INIT_WORK(&ifibss->work, ieee80211_ibss_work);
 770         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 771                     (unsigned long) sdata);
 772         skb_queue_head_init(&ifibss->skb_queue);
 773 }
 774
 775 /* scan finished notification */
 776 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 777 {
 778         struct ieee80211_sub_if_data *sdata;
 779
 780         mutex_lock(&local->iflist_mtx);
 781         list_for_each_entry(sdata, &local->interfaces, list) {
 782                 if (!netif_running(sdata->dev))
 783                         continue;
 784                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 785                         continue;
 786                 if (!sdata->u.ibss.ssid_len)
 787                         continue;
 788                 sdata->u.ibss.last_scan_completed = jiffies;
 789                 ieee80211_sta_find_ibss(sdata);
 790         }
 791         mutex_unlock(&local->iflist_mtx);
 792 }
 793
 794 ieee80211_rx_result
 795 ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 796                        struct ieee80211_rx_status *rx_status)
 797 {
 798         struct ieee80211_local *local = sdata->local;
 799         struct ieee80211_mgmt *mgmt;
 800         u16 fc;
 801
 802         if (skb->len < 24)
 803                 return RX_DROP_MONITOR;
 804
 805         mgmt = (struct ieee80211_mgmt *) skb->data;
 806         fc = le16_to_cpu(mgmt->frame_control);
 807
 808         switch (fc & IEEE80211_FCTL_STYPE) {
 809         case IEEE80211_STYPE_PROBE_RESP:
 810         case IEEE80211_STYPE_BEACON:
 811                 memcpy(skb->cb, rx_status, sizeof(*rx_status));
 812         case IEEE80211_STYPE_PROBE_REQ:
 813         case IEEE80211_STYPE_AUTH:
 814                 skb_queue_tail(&sdata->u.ibss.skb_queue, skb);
 815                 queue_work(local->hw.workqueue, &sdata->u.ibss.work);
 816                 return RX_QUEUED;
 817         }
 818
 819         return RX_DROP_MONITOR;
 820 }
 821
 822 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 823                         struct cfg80211_ibss_params *params)
 824 {
 825         struct sk_buff *skb;
 826
 827         if (params->bssid) {
 828                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 829                 sdata->u.ibss.fixed_bssid = true;
 830         } else
 831                 sdata->u.ibss.fixed_bssid = false;
 832
 833         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 834
 835         sdata->u.ibss.channel = params->channel;
 836         sdata->u.ibss.fixed_channel = params->channel_fixed;
 837
 838         if (params->ie) {
 839                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 840                                            GFP_KERNEL);
 841                 if (sdata->u.ibss.ie)
 842                         sdata->u.ibss.ie_len = params->ie_len;
 843         }
 844
 845         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 846                             36 /* bitrates */ +
 847                             34 /* SSID */ +
 848                             3  /* DS params */ +
 849                             4  /* IBSS params */ +
 850                             params->ie_len);
 851         if (!skb)
 852                 return -ENOMEM;
 853
 854         sdata->u.ibss.skb = skb;
 855         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 856         sdata->u.ibss.ibss_join_req = jiffies;
 857
 858         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 859
 860         /*
 861          * The ssid_len setting below is used to see whether
 862          * we are active, and we need all other settings
 863          * before that may get visible.
 864          */
 865         mb();
 866
 867         sdata->u.ibss.ssid_len = params->ssid_len;
 868
 869         set_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 870         queue_work(sdata->local->hw.workqueue, &sdata->u.ibss.work);
 871
 872         return 0;
 873 }
 874
 875 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 876 {
 877         struct sk_buff *skb;
 878
 879         del_timer_sync(&sdata->u.ibss.timer);
 880         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 881         cancel_work_sync(&sdata->u.ibss.work);
 882         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 883
 884         sta_info_flush(sdata->local, sdata);
 885
 886         /* remove beacon */
 887         kfree(sdata->u.ibss.ie);
 888         skb = sdata->u.ibss.presp;
 889         rcu_assign_pointer(sdata->u.ibss.presp, NULL);
 890         ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED);
 891         synchronize_rcu();
 892         kfree_skb(skb);
 893
 894         skb_queue_purge(&sdata->u.ibss.skb_queue);
 895         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
 896
 897         return 0;
 898 }