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/slab.h>
  17 #include <linux/if_ether.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/if_arp.h>
  20 #include <linux/etherdevice.h>
  21 #include <linux/rtnetlink.h>
  22 #include <net/mac80211.h>
  23 #include <asm/unaligned.h>
  24
  25 #include "ieee80211_i.h"
  26 #include "driver-ops.h"
  27 #include "rate.h"
  28
  29 #define IEEE80211_SCAN_INTERVAL (2 * HZ)
  30 #define IEEE80211_SCAN_INTERVAL_SLOW (15 * HZ)
  31 #define IEEE80211_IBSS_JOIN_TIMEOUT (7 * HZ)
  32
  33 #define IEEE80211_IBSS_MERGE_INTERVAL (30 * HZ)
  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;
  44
  45         lockdep_assert_held(&sdata->u.ibss.mtx);
  46
  47         if (len < 24 + 6)
  48                 return;
  49
  50         auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
  51         auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
  52
  53         /*
  54          * IEEE 802.11 standard does not require authentication in IBSS
  55          * networks and most implementations do not seem to use it.
  56          * However, try to reply to authentication attempts if someone
  57          * has actually implemented this.
  58          */
  59         if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
  60                 ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
  61                                     sdata->u.ibss.bssid, NULL, 0, 0);
  62 }
  63
  64 static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
  65                                       const u8 *bssid, const int beacon_int,
  66                                       struct ieee80211_channel *chan,
  67                                       const u32 basic_rates,
  68                                       const u16 capability, u64 tsf)
  69 {
  70         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
  71         struct ieee80211_local *local = sdata->local;
  72         int rates, i;
  73         struct sk_buff *skb;
  74         struct ieee80211_mgmt *mgmt;
  75         u8 *pos;
  76         struct ieee80211_supported_band *sband;
  77         struct cfg80211_bss *bss;
  78         u32 bss_change;
  79         u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
  80
  81         lockdep_assert_held(&ifibss->mtx);
  82
  83         /* Reset own TSF to allow time synchronization work. */
  84         drv_reset_tsf(local, sdata);
  85
  86         skb = ifibss->skb;
  87         RCU_INIT_POINTER(ifibss->presp, NULL);
  88         synchronize_rcu();
  89         skb->data = skb->head;
  90         skb->len = 0;
  91         skb_reset_tail_pointer(skb);
  92         skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
  93
  94         if (memcmp(ifibss->bssid, bssid, ETH_ALEN))
  95                 sta_info_flush(sdata->local, sdata);
  96
  97         /* if merging, indicate to driver that we leave the old IBSS */
  98         if (sdata->vif.bss_conf.ibss_joined) {
  99                 sdata->vif.bss_conf.ibss_joined = false;
 100                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
 101         }
 102
 103         memcpy(ifibss->bssid, bssid, ETH_ALEN);
 104
 105         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 106
 107         local->oper_channel = chan;
 108         WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
 109         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 110
 111         sband = local->hw.wiphy->bands[chan->band];
 112
 113         /* build supported rates array */
 114         pos = supp_rates;
 115         for (i = 0; i < sband->n_bitrates; i++) {
 116                 int rate = sband->bitrates[i].bitrate;
 117                 u8 basic = 0;
 118                 if (basic_rates & BIT(i))
 119                         basic = 0x80;
 120                 *pos++ = basic | (u8) (rate / 5);
 121         }
 122
 123         /* Build IBSS probe response */
 124         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 125         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 126         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 127                                           IEEE80211_STYPE_PROBE_RESP);
 128         memset(mgmt->da, 0xff, ETH_ALEN);
 129         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 130         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 131         mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
 132         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 133         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 134
 135         pos = skb_put(skb, 2 + ifibss->ssid_len);
 136         *pos++ = WLAN_EID_SSID;
 137         *pos++ = ifibss->ssid_len;
 138         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 139
 140         rates = sband->n_bitrates;
 141         if (rates > 8)
 142                 rates = 8;
 143         pos = skb_put(skb, 2 + rates);
 144         *pos++ = WLAN_EID_SUPP_RATES;
 145         *pos++ = rates;
 146         memcpy(pos, supp_rates, rates);
 147
 148         if (sband->band == IEEE80211_BAND_2GHZ) {
 149                 pos = skb_put(skb, 2 + 1);
 150                 *pos++ = WLAN_EID_DS_PARAMS;
 151                 *pos++ = 1;
 152                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 153         }
 154
 155         pos = skb_put(skb, 2 + 2);
 156         *pos++ = WLAN_EID_IBSS_PARAMS;
 157         *pos++ = 2;
 158         /* FIX: set ATIM window based on scan results */
 159         *pos++ = 0;
 160         *pos++ = 0;
 161
 162         if (sband->n_bitrates > 8) {
 163                 rates = sband->n_bitrates - 8;
 164                 pos = skb_put(skb, 2 + rates);
 165                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 166                 *pos++ = rates;
 167                 memcpy(pos, &supp_rates[8], rates);
 168         }
 169
 170         if (ifibss->ie_len)
 171                 memcpy(skb_put(skb, ifibss->ie_len),
 172                        ifibss->ie, ifibss->ie_len);
 173
 174         if (local->hw.queues >= 4) {
 175                 pos = skb_put(skb, 9);
 176                 *pos++ = WLAN_EID_VENDOR_SPECIFIC;
 177                 *pos++ = 7; /* len */
 178                 *pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
 179                 *pos++ = 0x50;
 180                 *pos++ = 0xf2;
 181                 *pos++ = 2; /* WME */
 182                 *pos++ = 0; /* WME info */
 183                 *pos++ = 1; /* WME ver */
 184                 *pos++ = 0; /* U-APSD no in use */
 185         }
 186
 187         RCU_INIT_POINTER(ifibss->presp, skb);
 188
 189         sdata->vif.bss_conf.beacon_int = beacon_int;
 190         sdata->vif.bss_conf.basic_rates = basic_rates;
 191         bss_change = BSS_CHANGED_BEACON_INT;
 192         bss_change |= ieee80211_reset_erp_info(sdata);
 193         bss_change |= BSS_CHANGED_BSSID;
 194         bss_change |= BSS_CHANGED_BEACON;
 195         bss_change |= BSS_CHANGED_BEACON_ENABLED;
 196         bss_change |= BSS_CHANGED_BASIC_RATES;
 197         bss_change |= BSS_CHANGED_IBSS;
 198         sdata->vif.bss_conf.ibss_joined = true;
 199         ieee80211_bss_info_change_notify(sdata, bss_change);
 200
 201         ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
 202
 203         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 204         mod_timer(&ifibss->timer,
 205                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 206
 207         bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 208                                         mgmt, skb->len, 0, GFP_KERNEL);
 209         cfg80211_put_bss(bss);
 210         cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
 211 }
 212
 213 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 214                                     struct ieee80211_bss *bss)
 215 {
 216         struct cfg80211_bss *cbss =
 217                 container_of((void *)bss, struct cfg80211_bss, priv);
 218         struct ieee80211_supported_band *sband;
 219         u32 basic_rates;
 220         int i, j;
 221         u16 beacon_int = cbss->beacon_interval;
 222
 223         lockdep_assert_held(&sdata->u.ibss.mtx);
 224
 225         if (beacon_int < 10)
 226                 beacon_int = 10;
 227
 228         sband = sdata->local->hw.wiphy->bands[cbss->channel->band];
 229
 230         basic_rates = 0;
 231
 232         for (i = 0; i < bss->supp_rates_len; i++) {
 233                 int rate = (bss->supp_rates[i] & 0x7f) * 5;
 234                 bool is_basic = !!(bss->supp_rates[i] & 0x80);
 235
 236                 for (j = 0; j < sband->n_bitrates; j++) {
 237                         if (sband->bitrates[j].bitrate == rate) {
 238                                 if (is_basic)
 239                                         basic_rates |= BIT(j);
 240                                 break;
 241                         }
 242                 }
 243         }
 244
 245         __ieee80211_sta_join_ibss(sdata, cbss->bssid,
 246                                   beacon_int,
 247                                   cbss->channel,
 248                                   basic_rates,
 249                                   cbss->capability,
 250                                   cbss->tsf);
 251 }
 252
 253 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 254                                   struct ieee80211_mgmt *mgmt,
 255                                   size_t len,
 256                                   struct ieee80211_rx_status *rx_status,
 257                                   struct ieee802_11_elems *elems,
 258                                   bool beacon)
 259 {
 260         struct ieee80211_local *local = sdata->local;
 261         int freq;
 262         struct cfg80211_bss *cbss;
 263         struct ieee80211_bss *bss;
 264         struct sta_info *sta;
 265         struct ieee80211_channel *channel;
 266         u64 beacon_timestamp, rx_timestamp;
 267         u32 supp_rates = 0;
 268         enum ieee80211_band band = rx_status->band;
 269
 270         if (elems->ds_params && elems->ds_params_len == 1)
 271                 freq = ieee80211_channel_to_frequency(elems->ds_params[0],
 272                                                       band);
 273         else
 274                 freq = rx_status->freq;
 275
 276         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 277
 278         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 279                 return;
 280
 281         if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 282             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 283
 284                 rcu_read_lock();
 285                 sta = sta_info_get(sdata, mgmt->sa);
 286
 287                 if (elems->supp_rates) {
 288                         supp_rates = ieee80211_sta_get_rates(local, elems,
 289                                                              band);
 290                         if (sta) {
 291                                 u32 prev_rates;
 292
 293                                 prev_rates = sta->sta.supp_rates[band];
 294                                 /* make sure mandatory rates are always added */
 295                                 sta->sta.supp_rates[band] = supp_rates |
 296                                         ieee80211_mandatory_rates(local, band);
 297
 298                                 if (sta->sta.supp_rates[band] != prev_rates) {
 299 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 300                                         printk(KERN_DEBUG
 301                                                 "%s: updated supp_rates set "
 302                                                 "for %pM based on beacon"
 303                                                 "/probe_resp (0x%x -> 0x%x)\n",
 304                                                 sdata->name, sta->sta.addr,
 305                                                 prev_rates,
 306                                                 sta->sta.supp_rates[band]);
 307 #endif
 308                                         rate_control_rate_init(sta);
 309                                 }
 310                         } else
 311                                 sta = ieee80211_ibss_add_sta(sdata, mgmt->bssid,
 312                                                 mgmt->sa, supp_rates,
 313                                                 GFP_ATOMIC);
 314                 }
 315
 316                 if (sta && elems->wmm_info)
 317                         set_sta_flag(sta, WLAN_STA_WME);
 318
 319                 rcu_read_unlock();
 320         }
 321
 322         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 323                                         channel, beacon);
 324         if (!bss)
 325                 return;
 326
 327         cbss = container_of((void *)bss, struct cfg80211_bss, priv);
 328
 329         /* was just updated in ieee80211_bss_info_update */
 330         beacon_timestamp = cbss->tsf;
 331
 332         /* check if we need to merge IBSS */
 333
 334         /* we use a fixed BSSID */
 335         if (sdata->u.ibss.fixed_bssid)
 336                 goto put_bss;
 337
 338         /* not an IBSS */
 339         if (!(cbss->capability & WLAN_CAPABILITY_IBSS))
 340                 goto put_bss;
 341
 342         /* different channel */
 343         if (cbss->channel != local->oper_channel)
 344                 goto put_bss;
 345
 346         /* different SSID */
 347         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 348             memcmp(elems->ssid, sdata->u.ibss.ssid,
 349                                 sdata->u.ibss.ssid_len))
 350                 goto put_bss;
 351
 352         /* same BSSID */
 353         if (memcmp(cbss->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 354                 goto put_bss;
 355
 356         if (rx_status->flag & RX_FLAG_MACTIME_MPDU) {
 357                 /*
 358                  * For correct IBSS merging we need mactime; since mactime is
 359                  * defined as the time the first data symbol of the frame hits
 360                  * the PHY, and the timestamp of the beacon is defined as "the
 361                  * time that the data symbol containing the first bit of the
 362                  * timestamp is transmitted to the PHY plus the transmitting
 363                  * STA's delays through its local PHY from the MAC-PHY
 364                  * interface to its interface with the WM" (802.11 11.1.2)
 365                  * - equals the time this bit arrives at the receiver - we have
 366                  * to take into account the offset between the two.
 367                  *
 368                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 369                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 370                  */
 371                 int rate;
 372
 373                 if (rx_status->flag & RX_FLAG_HT)
 374                         rate = 65; /* TODO: HT rates */
 375                 else
 376                         rate = local->hw.wiphy->bands[band]->
 377                                 bitrates[rx_status->rate_idx].bitrate;
 378
 379                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 380         } else {
 381                 /*
 382                  * second best option: get current TSF
 383                  * (will return -1 if not supported)
 384                  */
 385                 rx_timestamp = drv_get_tsf(local, sdata);
 386         }
 387
 388 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 389         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 390                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 391                mgmt->sa, mgmt->bssid,
 392                (unsigned long long)rx_timestamp,
 393                (unsigned long long)beacon_timestamp,
 394                (unsigned long long)(rx_timestamp - beacon_timestamp),
 395                jiffies);
 396 #endif
 397
 398         if (beacon_timestamp > rx_timestamp) {
 399 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 400                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 401                        "local TSF - IBSS merge with BSSID %pM\n",
 402                        sdata->name, mgmt->bssid);
 403 #endif
 404                 ieee80211_sta_join_ibss(sdata, bss);
 405                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 406                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 407                                        supp_rates, GFP_KERNEL);
 408         }
 409
 410  put_bss:
 411         ieee80211_rx_bss_put(local, bss);
 412 }
 413
 414 /*
 415  * Add a new IBSS station, will also be called by the RX code when,
 416  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 417  * must be callable in atomic context.
 418  */
 419 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 420                                         u8 *bssid, u8 *addr, u32 supp_rates,
 421                                         gfp_t gfp)
 422 {
 423         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 424         struct ieee80211_local *local = sdata->local;
 425         struct sta_info *sta;
 426         int band = local->hw.conf.channel->band;
 427
 428         /*
 429          * XXX: Consider removing the least recently used entry and
 430          *      allow new one to be added.
 431          */
 432         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 433                 if (net_ratelimit())
 434                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 435                                sdata->name, addr);
 436                 return NULL;
 437         }
 438
 439         if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
 440                 return NULL;
 441
 442         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 443                 return NULL;
 444
 445 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 446         wiphy_debug(local->hw.wiphy, "Adding new IBSS station %pM (dev=%s)\n",
 447                     addr, sdata->name);
 448 #endif
 449
 450         sta = sta_info_alloc(sdata, addr, gfp);
 451         if (!sta)
 452                 return NULL;
 453
 454         sta->last_rx = jiffies;
 455         set_sta_flag(sta, WLAN_STA_AUTHORIZED);
 456
 457         /* make sure mandatory rates are always added */
 458         sta->sta.supp_rates[band] = supp_rates |
 459                         ieee80211_mandatory_rates(local, band);
 460
 461         rate_control_rate_init(sta);
 462
 463         /* If it fails, maybe we raced another insertion? */
 464         if (sta_info_insert(sta))
 465                 return sta_info_get(sdata, addr);
 466         return sta;
 467 }
 468
 469 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 470 {
 471         struct ieee80211_local *local = sdata->local;
 472         int active = 0;
 473         struct sta_info *sta;
 474
 475         lockdep_assert_held(&sdata->u.ibss.mtx);
 476
 477         rcu_read_lock();
 478
 479         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 480                 if (sta->sdata == sdata &&
 481                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 482                                jiffies)) {
 483                         active++;
 484                         break;
 485                 }
 486         }
 487
 488         rcu_read_unlock();
 489
 490         return active;
 491 }
 492
 493 /*
 494  * This function is called with state == IEEE80211_IBSS_MLME_JOINED
 495  */
 496
 497 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 498 {
 499         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 500
 501         lockdep_assert_held(&ifibss->mtx);
 502
 503         mod_timer(&ifibss->timer,
 504                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 505
 506         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 507
 508         if (time_before(jiffies, ifibss->last_scan_completed +
 509                        IEEE80211_IBSS_MERGE_INTERVAL))
 510                 return;
 511
 512         if (ieee80211_sta_active_ibss(sdata))
 513                 return;
 514
 515         if (ifibss->fixed_channel)
 516                 return;
 517
 518         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 519                "IBSS networks with same SSID (merge)\n", sdata->name);
 520
 521         ieee80211_request_internal_scan(sdata,
 522                         ifibss->ssid, ifibss->ssid_len,
 523                         ifibss->fixed_channel ? ifibss->channel : NULL);
 524 }
 525
 526 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 527 {
 528         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 529         u8 bssid[ETH_ALEN];
 530         u16 capability;
 531         int i;
 532
 533         lockdep_assert_held(&ifibss->mtx);
 534
 535         if (ifibss->fixed_bssid) {
 536                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 537         } else {
 538                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 539                  * own MAC address to make sure that devices that do not have proper
 540                  * random number generator get different BSSID. */
 541                 get_random_bytes(bssid, ETH_ALEN);
 542                 for (i = 0; i < ETH_ALEN; i++)
 543                         bssid[i] ^= sdata->vif.addr[i];
 544                 bssid[0] &= ~0x01;
 545                 bssid[0] |= 0x02;
 546         }
 547
 548         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 549                sdata->name, bssid);
 550
 551         capability = WLAN_CAPABILITY_IBSS;
 552
 553         if (ifibss->privacy)
 554                 capability |= WLAN_CAPABILITY_PRIVACY;
 555         else
 556                 sdata->drop_unencrypted = 0;
 557
 558         __ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
 559                                   ifibss->channel, ifibss->basic_rates,
 560                                   capability, 0);
 561 }
 562
 563 /*
 564  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
 565  */
 566
 567 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 568 {
 569         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 570         struct ieee80211_local *local = sdata->local;
 571         struct cfg80211_bss *cbss;
 572         struct ieee80211_channel *chan = NULL;
 573         const u8 *bssid = NULL;
 574         int active_ibss;
 575         u16 capability;
 576
 577         lockdep_assert_held(&ifibss->mtx);
 578
 579         active_ibss = ieee80211_sta_active_ibss(sdata);
 580 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 581         printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
 582                sdata->name, active_ibss);
 583 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 584
 585         if (active_ibss)
 586                 return;
 587
 588         capability = WLAN_CAPABILITY_IBSS;
 589         if (ifibss->privacy)
 590                 capability |= WLAN_CAPABILITY_PRIVACY;
 591         if (ifibss->fixed_bssid)
 592                 bssid = ifibss->bssid;
 593         if (ifibss->fixed_channel)
 594                 chan = ifibss->channel;
 595         if (!is_zero_ether_addr(ifibss->bssid))
 596                 bssid = ifibss->bssid;
 597         cbss = cfg80211_get_bss(local->hw.wiphy, chan, bssid,
 598                                 ifibss->ssid, ifibss->ssid_len,
 599                                 WLAN_CAPABILITY_IBSS | WLAN_CAPABILITY_PRIVACY,
 600                                 capability);
 601
 602         if (cbss) {
 603                 struct ieee80211_bss *bss;
 604
 605                 bss = (void *)cbss->priv;
 606 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 607                 printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
 608                        "%pM\n", cbss->bssid, ifibss->bssid);
 609 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 610
 611                 printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
 612                        " based on configured SSID\n",
 613                        sdata->name, cbss->bssid);
 614
 615                 ieee80211_sta_join_ibss(sdata, bss);
 616                 ieee80211_rx_bss_put(local, bss);
 617                 return;
 618         }
 619
 620 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 621         printk(KERN_DEBUG "   did not try to join ibss\n");
 622 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 623
 624         /* Selected IBSS not found in current scan results - try to scan */
 625         if (time_after(jiffies, ifibss->last_scan_completed +
 626                                         IEEE80211_SCAN_INTERVAL)) {
 627                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
 628                        "join\n", sdata->name);
 629
 630                 ieee80211_request_internal_scan(sdata,
 631                                 ifibss->ssid, ifibss->ssid_len,
 632                                 ifibss->fixed_channel ? ifibss->channel : NULL);
 633         } else {
 634                 int interval = IEEE80211_SCAN_INTERVAL;
 635
 636                 if (time_after(jiffies, ifibss->ibss_join_req +
 637                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 638                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 639                                 ieee80211_sta_create_ibss(sdata);
 640                                 return;
 641                         }
 642                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 643                                " %d MHz\n", sdata->name,
 644                                local->hw.conf.channel->center_freq);
 645
 646                         /* No IBSS found - decrease scan interval and continue
 647                          * scanning. */
 648                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 649                 }
 650
 651                 mod_timer(&ifibss->timer,
 652                           round_jiffies(jiffies + interval));
 653         }
 654 }
 655
 656 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 657                                         struct sk_buff *req)
 658 {
 659         struct ieee80211_mgmt *mgmt = (void *)req->data;
 660         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 661         struct ieee80211_local *local = sdata->local;
 662         int tx_last_beacon, len = req->len;
 663         struct sk_buff *skb;
 664         struct ieee80211_mgmt *resp;
 665         struct sk_buff *presp;
 666         u8 *pos, *end;
 667
 668         lockdep_assert_held(&ifibss->mtx);
 669
 670         presp = rcu_dereference_protected(ifibss->presp,
 671                                           lockdep_is_held(&ifibss->mtx));
 672
 673         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 674             len < 24 + 2 || !presp)
 675                 return;
 676
 677         tx_last_beacon = drv_tx_last_beacon(local);
 678
 679 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 680         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 681                " (tx_last_beacon=%d)\n",
 682                sdata->name, mgmt->sa, mgmt->da,
 683                mgmt->bssid, tx_last_beacon);
 684 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 685
 686         if (!tx_last_beacon && is_multicast_ether_addr(mgmt->da))
 687                 return;
 688
 689         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 690             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 691                 return;
 692
 693         end = ((u8 *) mgmt) + len;
 694         pos = mgmt->u.probe_req.variable;
 695         if (pos[0] != WLAN_EID_SSID ||
 696             pos + 2 + pos[1] > end) {
 697 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 698                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 699                        "from %pM\n",
 700                        sdata->name, mgmt->sa);
 701 #endif
 702                 return;
 703         }
 704         if (pos[1] != 0 &&
 705             (pos[1] != ifibss->ssid_len ||
 706              memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 707                 /* Ignore ProbeReq for foreign SSID */
 708                 return;
 709         }
 710
 711         /* Reply with ProbeResp */
 712         skb = skb_copy(presp, GFP_KERNEL);
 713         if (!skb)
 714                 return;
 715
 716         resp = (struct ieee80211_mgmt *) skb->data;
 717         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 718 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 719         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 720                sdata->name, resp->da);
 721 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 722         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 723         ieee80211_tx_skb(sdata, skb);
 724 }
 725
 726 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 727                                          struct ieee80211_mgmt *mgmt,
 728                                          size_t len,
 729                                          struct ieee80211_rx_status *rx_status)
 730 {
 731         size_t baselen;
 732         struct ieee802_11_elems elems;
 733
 734         if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 735                 return; /* ignore ProbeResp to foreign address */
 736
 737         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 738         if (baselen > len)
 739                 return;
 740
 741         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 742                                 &elems);
 743
 744         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 745 }
 746
 747 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 748                                      struct ieee80211_mgmt *mgmt,
 749                                      size_t len,
 750                                      struct ieee80211_rx_status *rx_status)
 751 {
 752         size_t baselen;
 753         struct ieee802_11_elems elems;
 754
 755         /* Process beacon from the current BSS */
 756         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 757         if (baselen > len)
 758                 return;
 759
 760         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 761
 762         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 763 }
 764
 765 void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 766                                    struct sk_buff *skb)
 767 {
 768         struct ieee80211_rx_status *rx_status;
 769         struct ieee80211_mgmt *mgmt;
 770         u16 fc;
 771
 772         rx_status = IEEE80211_SKB_RXCB(skb);
 773         mgmt = (struct ieee80211_mgmt *) skb->data;
 774         fc = le16_to_cpu(mgmt->frame_control);
 775
 776         mutex_lock(&sdata->u.ibss.mtx);
 777
 778         if (!sdata->u.ibss.ssid_len)
 779                 goto mgmt_out; /* not ready to merge yet */
 780
 781         switch (fc & IEEE80211_FCTL_STYPE) {
 782         case IEEE80211_STYPE_PROBE_REQ:
 783                 ieee80211_rx_mgmt_probe_req(sdata, skb);
 784                 break;
 785         case IEEE80211_STYPE_PROBE_RESP:
 786                 ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
 787                                              rx_status);
 788                 break;
 789         case IEEE80211_STYPE_BEACON:
 790                 ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
 791                                          rx_status);
 792                 break;
 793         case IEEE80211_STYPE_AUTH:
 794                 ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
 795                 break;
 796         }
 797
 798  mgmt_out:
 799         mutex_unlock(&sdata->u.ibss.mtx);
 800 }
 801
 802 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
 803 {
 804         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 805
 806         mutex_lock(&ifibss->mtx);
 807
 808         /*
 809          * Work could be scheduled after scan or similar
 810          * when we aren't even joined (or trying) with a
 811          * network.
 812          */
 813         if (!ifibss->ssid_len)
 814                 goto out;
 815
 816         switch (ifibss->state) {
 817         case IEEE80211_IBSS_MLME_SEARCH:
 818                 ieee80211_sta_find_ibss(sdata);
 819                 break;
 820         case IEEE80211_IBSS_MLME_JOINED:
 821                 ieee80211_sta_merge_ibss(sdata);
 822                 break;
 823         default:
 824                 WARN_ON(1);
 825                 break;
 826         }
 827
 828  out:
 829         mutex_unlock(&ifibss->mtx);
 830 }
 831
 832 static void ieee80211_ibss_timer(unsigned long data)
 833 {
 834         struct ieee80211_sub_if_data *sdata =
 835                 (struct ieee80211_sub_if_data *) data;
 836         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 837         struct ieee80211_local *local = sdata->local;
 838
 839         if (local->quiescing) {
 840                 ifibss->timer_running = true;
 841                 return;
 842         }
 843
 844         ieee80211_queue_work(&local->hw, &sdata->work);
 845 }
 846
 847 #ifdef CONFIG_PM
 848 void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
 849 {
 850         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 851
 852         if (del_timer_sync(&ifibss->timer))
 853                 ifibss->timer_running = true;
 854 }
 855
 856 void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
 857 {
 858         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 859
 860         if (ifibss->timer_running) {
 861                 add_timer(&ifibss->timer);
 862                 ifibss->timer_running = false;
 863         }
 864 }
 865 #endif
 866
 867 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 868 {
 869         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 870
 871         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 872                     (unsigned long) sdata);
 873         mutex_init(&ifibss->mtx);
 874 }
 875
 876 /* scan finished notification */
 877 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 878 {
 879         struct ieee80211_sub_if_data *sdata;
 880
 881         mutex_lock(&local->iflist_mtx);
 882         list_for_each_entry(sdata, &local->interfaces, list) {
 883                 if (!ieee80211_sdata_running(sdata))
 884                         continue;
 885                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 886                         continue;
 887                 sdata->u.ibss.last_scan_completed = jiffies;
 888                 ieee80211_queue_work(&local->hw, &sdata->work);
 889         }
 890         mutex_unlock(&local->iflist_mtx);
 891 }
 892
 893 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 894                         struct cfg80211_ibss_params *params)
 895 {
 896         struct sk_buff *skb;
 897
 898         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 899                             36 /* bitrates */ +
 900                             34 /* SSID */ +
 901                             3  /* DS params */ +
 902                             4  /* IBSS params */ +
 903                             params->ie_len);
 904         if (!skb)
 905                 return -ENOMEM;
 906
 907         mutex_lock(&sdata->u.ibss.mtx);
 908
 909         if (params->bssid) {
 910                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 911                 sdata->u.ibss.fixed_bssid = true;
 912         } else
 913                 sdata->u.ibss.fixed_bssid = false;
 914
 915         sdata->u.ibss.privacy = params->privacy;
 916         sdata->u.ibss.basic_rates = params->basic_rates;
 917         memcpy(sdata->vif.bss_conf.mcast_rate, params->mcast_rate,
 918                sizeof(params->mcast_rate));
 919
 920         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 921
 922         sdata->u.ibss.channel = params->channel;
 923         sdata->u.ibss.fixed_channel = params->channel_fixed;
 924
 925         /* fix ourselves to that channel now already */
 926         if (params->channel_fixed) {
 927                 sdata->local->oper_channel = params->channel;
 928                 WARN_ON(!ieee80211_set_channel_type(sdata->local, sdata,
 929                                                     NL80211_CHAN_NO_HT));
 930         }
 931
 932         if (params->ie) {
 933                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 934                                            GFP_KERNEL);
 935                 if (sdata->u.ibss.ie)
 936                         sdata->u.ibss.ie_len = params->ie_len;
 937         }
 938
 939         sdata->u.ibss.skb = skb;
 940         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 941         sdata->u.ibss.ibss_join_req = jiffies;
 942
 943         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 944         sdata->u.ibss.ssid_len = params->ssid_len;
 945
 946         mutex_unlock(&sdata->u.ibss.mtx);
 947
 948         mutex_lock(&sdata->local->mtx);
 949         ieee80211_recalc_idle(sdata->local);
 950         mutex_unlock(&sdata->local->mtx);
 951
 952         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 953
 954         return 0;
 955 }
 956
 957 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 958 {
 959         struct sk_buff *skb;
 960         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 961         struct ieee80211_local *local = sdata->local;
 962         struct cfg80211_bss *cbss;
 963         u16 capability;
 964         int active_ibss;
 965
 966         mutex_lock(&sdata->u.ibss.mtx);
 967
 968         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 969         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
 970         sdata->u.ibss.ssid_len = 0;
 971
 972         active_ibss = ieee80211_sta_active_ibss(sdata);
 973
 974         if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
 975                 capability = WLAN_CAPABILITY_IBSS;
 976
 977                 if (ifibss->privacy)
 978                         capability |= WLAN_CAPABILITY_PRIVACY;
 979
 980                 cbss = cfg80211_get_bss(local->hw.wiphy, ifibss->channel,
 981                                         ifibss->bssid, ifibss->ssid,
 982                                         ifibss->ssid_len, WLAN_CAPABILITY_IBSS |
 983                                         WLAN_CAPABILITY_PRIVACY,
 984                                         capability);
 985
 986                 if (cbss) {
 987                         cfg80211_unlink_bss(local->hw.wiphy, cbss);
 988                         cfg80211_put_bss(cbss);
 989                 }
 990         }
 991
 992         sta_info_flush(sdata->local, sdata);
 993
 994         /* remove beacon */
 995         kfree(sdata->u.ibss.ie);
 996         skb = rcu_dereference_protected(sdata->u.ibss.presp,
 997                                         lockdep_is_held(&sdata->u.ibss.mtx));
 998         RCU_INIT_POINTER(sdata->u.ibss.presp, NULL);
 999         sdata->vif.bss_conf.ibss_joined = false;
1000         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
1001                                                 BSS_CHANGED_IBSS);
1002         synchronize_rcu();
1003         kfree_skb(skb);
1004
1005         skb_queue_purge(&sdata->skb_queue);
1006
1007         del_timer_sync(&sdata->u.ibss.timer);
1008
1009         mutex_unlock(&sdata->u.ibss.mtx);
1010
1011         mutex_lock(&local->mtx);
1012         ieee80211_recalc_idle(sdata->local);
1013         mutex_unlock(&local->mtx);
1014
1015         return 0;
1016 }