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                 netif_carrier_off(sdata->dev);
 101                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
 102         }
 103
 104         memcpy(ifibss->bssid, bssid, ETH_ALEN);
 105
 106         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 107
 108         local->oper_channel = chan;
 109         WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
 110         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 111
 112         sband = local->hw.wiphy->bands[chan->band];
 113
 114         /* build supported rates array */
 115         pos = supp_rates;
 116         for (i = 0; i < sband->n_bitrates; i++) {
 117                 int rate = sband->bitrates[i].bitrate;
 118                 u8 basic = 0;
 119                 if (basic_rates & BIT(i))
 120                         basic = 0x80;
 121                 *pos++ = basic | (u8) (rate / 5);
 122         }
 123
 124         /* Build IBSS probe response */
 125         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 126         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 127         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 128                                           IEEE80211_STYPE_PROBE_RESP);
 129         memset(mgmt->da, 0xff, ETH_ALEN);
 130         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 131         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 132         mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
 133         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 134         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 135
 136         pos = skb_put(skb, 2 + ifibss->ssid_len);
 137         *pos++ = WLAN_EID_SSID;
 138         *pos++ = ifibss->ssid_len;
 139         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 140
 141         rates = sband->n_bitrates;
 142         if (rates > 8)
 143                 rates = 8;
 144         pos = skb_put(skb, 2 + rates);
 145         *pos++ = WLAN_EID_SUPP_RATES;
 146         *pos++ = rates;
 147         memcpy(pos, supp_rates, rates);
 148
 149         if (sband->band == IEEE80211_BAND_2GHZ) {
 150                 pos = skb_put(skb, 2 + 1);
 151                 *pos++ = WLAN_EID_DS_PARAMS;
 152                 *pos++ = 1;
 153                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 154         }
 155
 156         pos = skb_put(skb, 2 + 2);
 157         *pos++ = WLAN_EID_IBSS_PARAMS;
 158         *pos++ = 2;
 159         /* FIX: set ATIM window based on scan results */
 160         *pos++ = 0;
 161         *pos++ = 0;
 162
 163         if (sband->n_bitrates > 8) {
 164                 rates = sband->n_bitrates - 8;
 165                 pos = skb_put(skb, 2 + rates);
 166                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 167                 *pos++ = rates;
 168                 memcpy(pos, &supp_rates[8], rates);
 169         }
 170
 171         if (ifibss->ie_len)
 172                 memcpy(skb_put(skb, ifibss->ie_len),
 173                        ifibss->ie, ifibss->ie_len);
 174
 175         if (local->hw.queues >= 4) {
 176                 pos = skb_put(skb, 9);
 177                 *pos++ = WLAN_EID_VENDOR_SPECIFIC;
 178                 *pos++ = 7; /* len */
 179                 *pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
 180                 *pos++ = 0x50;
 181                 *pos++ = 0xf2;
 182                 *pos++ = 2; /* WME */
 183                 *pos++ = 0; /* WME info */
 184                 *pos++ = 1; /* WME ver */
 185                 *pos++ = 0; /* U-APSD no in use */
 186         }
 187
 188         RCU_INIT_POINTER(ifibss->presp, skb);
 189
 190         sdata->vif.bss_conf.beacon_int = beacon_int;
 191         sdata->vif.bss_conf.basic_rates = basic_rates;
 192         bss_change = BSS_CHANGED_BEACON_INT;
 193         bss_change |= ieee80211_reset_erp_info(sdata);
 194         bss_change |= BSS_CHANGED_BSSID;
 195         bss_change |= BSS_CHANGED_BEACON;
 196         bss_change |= BSS_CHANGED_BEACON_ENABLED;
 197         bss_change |= BSS_CHANGED_BASIC_RATES;
 198         bss_change |= BSS_CHANGED_IBSS;
 199         sdata->vif.bss_conf.ibss_joined = true;
 200         ieee80211_bss_info_change_notify(sdata, bss_change);
 201
 202         ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
 203
 204         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 205         mod_timer(&ifibss->timer,
 206                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 207
 208         bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 209                                         mgmt, skb->len, 0, GFP_KERNEL);
 210         cfg80211_put_bss(bss);
 211         netif_carrier_on(sdata->dev);
 212         cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
 213 }
 214
 215 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 216                                     struct ieee80211_bss *bss)
 217 {
 218         struct cfg80211_bss *cbss =
 219                 container_of((void *)bss, struct cfg80211_bss, priv);
 220         struct ieee80211_supported_band *sband;
 221         u32 basic_rates;
 222         int i, j;
 223         u16 beacon_int = cbss->beacon_interval;
 224
 225         lockdep_assert_held(&sdata->u.ibss.mtx);
 226
 227         if (beacon_int < 10)
 228                 beacon_int = 10;
 229
 230         sband = sdata->local->hw.wiphy->bands[cbss->channel->band];
 231
 232         basic_rates = 0;
 233
 234         for (i = 0; i < bss->supp_rates_len; i++) {
 235                 int rate = (bss->supp_rates[i] & 0x7f) * 5;
 236                 bool is_basic = !!(bss->supp_rates[i] & 0x80);
 237
 238                 for (j = 0; j < sband->n_bitrates; j++) {
 239                         if (sband->bitrates[j].bitrate == rate) {
 240                                 if (is_basic)
 241                                         basic_rates |= BIT(j);
 242                                 break;
 243                         }
 244                 }
 245         }
 246
 247         __ieee80211_sta_join_ibss(sdata, cbss->bssid,
 248                                   beacon_int,
 249                                   cbss->channel,
 250                                   basic_rates,
 251                                   cbss->capability,
 252                                   cbss->tsf);
 253 }
 254
 255 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 256                                   struct ieee80211_mgmt *mgmt,
 257                                   size_t len,
 258                                   struct ieee80211_rx_status *rx_status,
 259                                   struct ieee802_11_elems *elems,
 260                                   bool beacon)
 261 {
 262         struct ieee80211_local *local = sdata->local;
 263         int freq;
 264         struct cfg80211_bss *cbss;
 265         struct ieee80211_bss *bss;
 266         struct sta_info *sta;
 267         struct ieee80211_channel *channel;
 268         u64 beacon_timestamp, rx_timestamp;
 269         u32 supp_rates = 0;
 270         enum ieee80211_band band = rx_status->band;
 271
 272         if (elems->ds_params && elems->ds_params_len == 1)
 273                 freq = ieee80211_channel_to_frequency(elems->ds_params[0],
 274                                                       band);
 275         else
 276                 freq = rx_status->freq;
 277
 278         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 279
 280         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 281                 return;
 282
 283         if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 284             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 285
 286                 rcu_read_lock();
 287                 sta = sta_info_get(sdata, mgmt->sa);
 288
 289                 if (elems->supp_rates) {
 290                         supp_rates = ieee80211_sta_get_rates(local, elems,
 291                                                              band);
 292                         if (sta) {
 293                                 u32 prev_rates;
 294
 295                                 prev_rates = sta->sta.supp_rates[band];
 296                                 /* make sure mandatory rates are always added */
 297                                 sta->sta.supp_rates[band] = supp_rates |
 298                                         ieee80211_mandatory_rates(local, band);
 299
 300                                 if (sta->sta.supp_rates[band] != prev_rates) {
 301 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 302                                         printk(KERN_DEBUG
 303                                                 "%s: updated supp_rates set "
 304                                                 "for %pM based on beacon"
 305                                                 "/probe_resp (0x%x -> 0x%x)\n",
 306                                                 sdata->name, sta->sta.addr,
 307                                                 prev_rates,
 308                                                 sta->sta.supp_rates[band]);
 309 #endif
 310                                         rate_control_rate_init(sta);
 311                                 }
 312                         } else
 313                                 sta = ieee80211_ibss_add_sta(sdata, mgmt->bssid,
 314                                                 mgmt->sa, supp_rates,
 315                                                 GFP_ATOMIC);
 316                 }
 317
 318                 if (sta && elems->wmm_info)
 319                         set_sta_flag(sta, WLAN_STA_WME);
 320
 321                 rcu_read_unlock();
 322         }
 323
 324         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 325                                         channel, beacon);
 326         if (!bss)
 327                 return;
 328
 329         cbss = container_of((void *)bss, struct cfg80211_bss, priv);
 330
 331         /* was just updated in ieee80211_bss_info_update */
 332         beacon_timestamp = cbss->tsf;
 333
 334         /* check if we need to merge IBSS */
 335
 336         /* we use a fixed BSSID */
 337         if (sdata->u.ibss.fixed_bssid)
 338                 goto put_bss;
 339
 340         /* not an IBSS */
 341         if (!(cbss->capability & WLAN_CAPABILITY_IBSS))
 342                 goto put_bss;
 343
 344         /* different channel */
 345         if (cbss->channel != local->oper_channel)
 346                 goto put_bss;
 347
 348         /* different SSID */
 349         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 350             memcmp(elems->ssid, sdata->u.ibss.ssid,
 351                                 sdata->u.ibss.ssid_len))
 352                 goto put_bss;
 353
 354         /* same BSSID */
 355         if (memcmp(cbss->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 356                 goto put_bss;
 357
 358         if (rx_status->flag & RX_FLAG_MACTIME_MPDU) {
 359                 /*
 360                  * For correct IBSS merging we need mactime; since mactime is
 361                  * defined as the time the first data symbol of the frame hits
 362                  * the PHY, and the timestamp of the beacon is defined as "the
 363                  * time that the data symbol containing the first bit of the
 364                  * timestamp is transmitted to the PHY plus the transmitting
 365                  * STA's delays through its local PHY from the MAC-PHY
 366                  * interface to its interface with the WM" (802.11 11.1.2)
 367                  * - equals the time this bit arrives at the receiver - we have
 368                  * to take into account the offset between the two.
 369                  *
 370                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 371                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 372                  */
 373                 int rate;
 374
 375                 if (rx_status->flag & RX_FLAG_HT)
 376                         rate = 65; /* TODO: HT rates */
 377                 else
 378                         rate = local->hw.wiphy->bands[band]->
 379                                 bitrates[rx_status->rate_idx].bitrate;
 380
 381                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 382         } else {
 383                 /*
 384                  * second best option: get current TSF
 385                  * (will return -1 if not supported)
 386                  */
 387                 rx_timestamp = drv_get_tsf(local, sdata);
 388         }
 389
 390 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 391         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 392                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 393                mgmt->sa, mgmt->bssid,
 394                (unsigned long long)rx_timestamp,
 395                (unsigned long long)beacon_timestamp,
 396                (unsigned long long)(rx_timestamp - beacon_timestamp),
 397                jiffies);
 398 #endif
 399
 400         if (beacon_timestamp > rx_timestamp) {
 401 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 402                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 403                        "local TSF - IBSS merge with BSSID %pM\n",
 404                        sdata->name, mgmt->bssid);
 405 #endif
 406                 ieee80211_sta_join_ibss(sdata, bss);
 407                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 408                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 409                                        supp_rates, GFP_KERNEL);
 410         }
 411
 412  put_bss:
 413         ieee80211_rx_bss_put(local, bss);
 414 }
 415
 416 /*
 417  * Add a new IBSS station, will also be called by the RX code when,
 418  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 419  * must be callable in atomic context.
 420  */
 421 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 422                                         u8 *bssid, u8 *addr, u32 supp_rates,
 423                                         gfp_t gfp)
 424 {
 425         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 426         struct ieee80211_local *local = sdata->local;
 427         struct sta_info *sta;
 428         int band = local->hw.conf.channel->band;
 429
 430         /*
 431          * XXX: Consider removing the least recently used entry and
 432          *      allow new one to be added.
 433          */
 434         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 435                 if (net_ratelimit())
 436                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 437                                sdata->name, addr);
 438                 return NULL;
 439         }
 440
 441         if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
 442                 return NULL;
 443
 444         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 445                 return NULL;
 446
 447 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 448         wiphy_debug(local->hw.wiphy, "Adding new IBSS station %pM (dev=%s)\n",
 449                     addr, sdata->name);
 450 #endif
 451
 452         sta = sta_info_alloc(sdata, addr, gfp);
 453         if (!sta)
 454                 return NULL;
 455
 456         sta->last_rx = jiffies;
 457         set_sta_flag(sta, WLAN_STA_AUTHORIZED);
 458
 459         /* make sure mandatory rates are always added */
 460         sta->sta.supp_rates[band] = supp_rates |
 461                         ieee80211_mandatory_rates(local, band);
 462
 463         rate_control_rate_init(sta);
 464
 465         /* If it fails, maybe we raced another insertion? */
 466         if (sta_info_insert(sta))
 467                 return sta_info_get(sdata, addr);
 468         return sta;
 469 }
 470
 471 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 472 {
 473         struct ieee80211_local *local = sdata->local;
 474         int active = 0;
 475         struct sta_info *sta;
 476
 477         lockdep_assert_held(&sdata->u.ibss.mtx);
 478
 479         rcu_read_lock();
 480
 481         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 482                 if (sta->sdata == sdata &&
 483                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 484                                jiffies)) {
 485                         active++;
 486                         break;
 487                 }
 488         }
 489
 490         rcu_read_unlock();
 491
 492         return active;
 493 }
 494
 495 /*
 496  * This function is called with state == IEEE80211_IBSS_MLME_JOINED
 497  */
 498
 499 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 500 {
 501         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 502
 503         lockdep_assert_held(&ifibss->mtx);
 504
 505         mod_timer(&ifibss->timer,
 506                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 507
 508         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 509
 510         if (time_before(jiffies, ifibss->last_scan_completed +
 511                        IEEE80211_IBSS_MERGE_INTERVAL))
 512                 return;
 513
 514         if (ieee80211_sta_active_ibss(sdata))
 515                 return;
 516
 517         if (ifibss->fixed_channel)
 518                 return;
 519
 520         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 521                "IBSS networks with same SSID (merge)\n", sdata->name);
 522
 523         ieee80211_request_internal_scan(sdata,
 524                         ifibss->ssid, ifibss->ssid_len,
 525                         ifibss->fixed_channel ? ifibss->channel : NULL);
 526 }
 527
 528 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 529 {
 530         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 531         u8 bssid[ETH_ALEN];
 532         u16 capability;
 533         int i;
 534
 535         lockdep_assert_held(&ifibss->mtx);
 536
 537         if (ifibss->fixed_bssid) {
 538                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 539         } else {
 540                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 541                  * own MAC address to make sure that devices that do not have proper
 542                  * random number generator get different BSSID. */
 543                 get_random_bytes(bssid, ETH_ALEN);
 544                 for (i = 0; i < ETH_ALEN; i++)
 545                         bssid[i] ^= sdata->vif.addr[i];
 546                 bssid[0] &= ~0x01;
 547                 bssid[0] |= 0x02;
 548         }
 549
 550         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 551                sdata->name, bssid);
 552
 553         capability = WLAN_CAPABILITY_IBSS;
 554
 555         if (ifibss->privacy)
 556                 capability |= WLAN_CAPABILITY_PRIVACY;
 557         else
 558                 sdata->drop_unencrypted = 0;
 559
 560         __ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
 561                                   ifibss->channel, ifibss->basic_rates,
 562                                   capability, 0);
 563 }
 564
 565 /*
 566  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
 567  */
 568
 569 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 570 {
 571         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 572         struct ieee80211_local *local = sdata->local;
 573         struct cfg80211_bss *cbss;
 574         struct ieee80211_channel *chan = NULL;
 575         const u8 *bssid = NULL;
 576         int active_ibss;
 577         u16 capability;
 578
 579         lockdep_assert_held(&ifibss->mtx);
 580
 581         active_ibss = ieee80211_sta_active_ibss(sdata);
 582 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 583         printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
 584                sdata->name, active_ibss);
 585 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 586
 587         if (active_ibss)
 588                 return;
 589
 590         capability = WLAN_CAPABILITY_IBSS;
 591         if (ifibss->privacy)
 592                 capability |= WLAN_CAPABILITY_PRIVACY;
 593         if (ifibss->fixed_bssid)
 594                 bssid = ifibss->bssid;
 595         if (ifibss->fixed_channel)
 596                 chan = ifibss->channel;
 597         if (!is_zero_ether_addr(ifibss->bssid))
 598                 bssid = ifibss->bssid;
 599         cbss = cfg80211_get_bss(local->hw.wiphy, chan, bssid,
 600                                 ifibss->ssid, ifibss->ssid_len,
 601                                 WLAN_CAPABILITY_IBSS | WLAN_CAPABILITY_PRIVACY,
 602                                 capability);
 603
 604         if (cbss) {
 605                 struct ieee80211_bss *bss;
 606
 607                 bss = (void *)cbss->priv;
 608 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 609                 printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
 610                        "%pM\n", cbss->bssid, ifibss->bssid);
 611 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 612
 613                 printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
 614                        " based on configured SSID\n",
 615                        sdata->name, cbss->bssid);
 616
 617                 ieee80211_sta_join_ibss(sdata, bss);
 618                 ieee80211_rx_bss_put(local, bss);
 619                 return;
 620         }
 621
 622 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 623         printk(KERN_DEBUG "   did not try to join ibss\n");
 624 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 625
 626         /* Selected IBSS not found in current scan results - try to scan */
 627         if (time_after(jiffies, ifibss->last_scan_completed +
 628                                         IEEE80211_SCAN_INTERVAL)) {
 629                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
 630                        "join\n", sdata->name);
 631
 632                 ieee80211_request_internal_scan(sdata,
 633                                 ifibss->ssid, ifibss->ssid_len,
 634                                 ifibss->fixed_channel ? ifibss->channel : NULL);
 635         } else {
 636                 int interval = IEEE80211_SCAN_INTERVAL;
 637
 638                 if (time_after(jiffies, ifibss->ibss_join_req +
 639                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 640                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 641                                 ieee80211_sta_create_ibss(sdata);
 642                                 return;
 643                         }
 644                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 645                                " %d MHz\n", sdata->name,
 646                                local->hw.conf.channel->center_freq);
 647
 648                         /* No IBSS found - decrease scan interval and continue
 649                          * scanning. */
 650                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 651                 }
 652
 653                 mod_timer(&ifibss->timer,
 654                           round_jiffies(jiffies + interval));
 655         }
 656 }
 657
 658 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 659                                         struct sk_buff *req)
 660 {
 661         struct ieee80211_mgmt *mgmt = (void *)req->data;
 662         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 663         struct ieee80211_local *local = sdata->local;
 664         int tx_last_beacon, len = req->len;
 665         struct sk_buff *skb;
 666         struct ieee80211_mgmt *resp;
 667         struct sk_buff *presp;
 668         u8 *pos, *end;
 669
 670         lockdep_assert_held(&ifibss->mtx);
 671
 672         presp = rcu_dereference_protected(ifibss->presp,
 673                                           lockdep_is_held(&ifibss->mtx));
 674
 675         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 676             len < 24 + 2 || !presp)
 677                 return;
 678
 679         tx_last_beacon = drv_tx_last_beacon(local);
 680
 681 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 682         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 683                " (tx_last_beacon=%d)\n",
 684                sdata->name, mgmt->sa, mgmt->da,
 685                mgmt->bssid, tx_last_beacon);
 686 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 687
 688         if (!tx_last_beacon && is_multicast_ether_addr(mgmt->da))
 689                 return;
 690
 691         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 692             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 693                 return;
 694
 695         end = ((u8 *) mgmt) + len;
 696         pos = mgmt->u.probe_req.variable;
 697         if (pos[0] != WLAN_EID_SSID ||
 698             pos + 2 + pos[1] > end) {
 699 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 700                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 701                        "from %pM\n",
 702                        sdata->name, mgmt->sa);
 703 #endif
 704                 return;
 705         }
 706         if (pos[1] != 0 &&
 707             (pos[1] != ifibss->ssid_len ||
 708              memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 709                 /* Ignore ProbeReq for foreign SSID */
 710                 return;
 711         }
 712
 713         /* Reply with ProbeResp */
 714         skb = skb_copy(presp, GFP_KERNEL);
 715         if (!skb)
 716                 return;
 717
 718         resp = (struct ieee80211_mgmt *) skb->data;
 719         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 720 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 721         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 722                sdata->name, resp->da);
 723 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 724         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 725         ieee80211_tx_skb(sdata, skb);
 726 }
 727
 728 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 729                                          struct ieee80211_mgmt *mgmt,
 730                                          size_t len,
 731                                          struct ieee80211_rx_status *rx_status)
 732 {
 733         size_t baselen;
 734         struct ieee802_11_elems elems;
 735
 736         if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 737                 return; /* ignore ProbeResp to foreign address */
 738
 739         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 740         if (baselen > len)
 741                 return;
 742
 743         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 744                                 &elems);
 745
 746         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 747 }
 748
 749 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 750                                      struct ieee80211_mgmt *mgmt,
 751                                      size_t len,
 752                                      struct ieee80211_rx_status *rx_status)
 753 {
 754         size_t baselen;
 755         struct ieee802_11_elems elems;
 756
 757         /* Process beacon from the current BSS */
 758         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 759         if (baselen > len)
 760                 return;
 761
 762         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 763
 764         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 765 }
 766
 767 void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 768                                    struct sk_buff *skb)
 769 {
 770         struct ieee80211_rx_status *rx_status;
 771         struct ieee80211_mgmt *mgmt;
 772         u16 fc;
 773
 774         rx_status = IEEE80211_SKB_RXCB(skb);
 775         mgmt = (struct ieee80211_mgmt *) skb->data;
 776         fc = le16_to_cpu(mgmt->frame_control);
 777
 778         mutex_lock(&sdata->u.ibss.mtx);
 779
 780         if (!sdata->u.ibss.ssid_len)
 781                 goto mgmt_out; /* not ready to merge yet */
 782
 783         switch (fc & IEEE80211_FCTL_STYPE) {
 784         case IEEE80211_STYPE_PROBE_REQ:
 785                 ieee80211_rx_mgmt_probe_req(sdata, skb);
 786                 break;
 787         case IEEE80211_STYPE_PROBE_RESP:
 788                 ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
 789                                              rx_status);
 790                 break;
 791         case IEEE80211_STYPE_BEACON:
 792                 ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
 793                                          rx_status);
 794                 break;
 795         case IEEE80211_STYPE_AUTH:
 796                 ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
 797                 break;
 798         }
 799
 800  mgmt_out:
 801         mutex_unlock(&sdata->u.ibss.mtx);
 802 }
 803
 804 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
 805 {
 806         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 807
 808         mutex_lock(&ifibss->mtx);
 809
 810         /*
 811          * Work could be scheduled after scan or similar
 812          * when we aren't even joined (or trying) with a
 813          * network.
 814          */
 815         if (!ifibss->ssid_len)
 816                 goto out;
 817
 818         switch (ifibss->state) {
 819         case IEEE80211_IBSS_MLME_SEARCH:
 820                 ieee80211_sta_find_ibss(sdata);
 821                 break;
 822         case IEEE80211_IBSS_MLME_JOINED:
 823                 ieee80211_sta_merge_ibss(sdata);
 824                 break;
 825         default:
 826                 WARN_ON(1);
 827                 break;
 828         }
 829
 830  out:
 831         mutex_unlock(&ifibss->mtx);
 832 }
 833
 834 static void ieee80211_ibss_timer(unsigned long data)
 835 {
 836         struct ieee80211_sub_if_data *sdata =
 837                 (struct ieee80211_sub_if_data *) data;
 838         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 839         struct ieee80211_local *local = sdata->local;
 840
 841         if (local->quiescing) {
 842                 ifibss->timer_running = true;
 843                 return;
 844         }
 845
 846         ieee80211_queue_work(&local->hw, &sdata->work);
 847 }
 848
 849 #ifdef CONFIG_PM
 850 void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
 851 {
 852         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 853
 854         if (del_timer_sync(&ifibss->timer))
 855                 ifibss->timer_running = true;
 856 }
 857
 858 void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
 859 {
 860         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 861
 862         if (ifibss->timer_running) {
 863                 add_timer(&ifibss->timer);
 864                 ifibss->timer_running = false;
 865         }
 866 }
 867 #endif
 868
 869 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 870 {
 871         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 872
 873         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 874                     (unsigned long) sdata);
 875         mutex_init(&ifibss->mtx);
 876 }
 877
 878 /* scan finished notification */
 879 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 880 {
 881         struct ieee80211_sub_if_data *sdata;
 882
 883         mutex_lock(&local->iflist_mtx);
 884         list_for_each_entry(sdata, &local->interfaces, list) {
 885                 if (!ieee80211_sdata_running(sdata))
 886                         continue;
 887                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 888                         continue;
 889                 sdata->u.ibss.last_scan_completed = jiffies;
 890                 ieee80211_queue_work(&local->hw, &sdata->work);
 891         }
 892         mutex_unlock(&local->iflist_mtx);
 893 }
 894
 895 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 896                         struct cfg80211_ibss_params *params)
 897 {
 898         struct sk_buff *skb;
 899
 900         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 901                             36 /* bitrates */ +
 902                             34 /* SSID */ +
 903                             3  /* DS params */ +
 904                             4  /* IBSS params */ +
 905                             params->ie_len);
 906         if (!skb)
 907                 return -ENOMEM;
 908
 909         mutex_lock(&sdata->u.ibss.mtx);
 910
 911         if (params->bssid) {
 912                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 913                 sdata->u.ibss.fixed_bssid = true;
 914         } else
 915                 sdata->u.ibss.fixed_bssid = false;
 916
 917         sdata->u.ibss.privacy = params->privacy;
 918         sdata->u.ibss.basic_rates = params->basic_rates;
 919         memcpy(sdata->vif.bss_conf.mcast_rate, params->mcast_rate,
 920                sizeof(params->mcast_rate));
 921
 922         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 923
 924         sdata->u.ibss.channel = params->channel;
 925         sdata->u.ibss.fixed_channel = params->channel_fixed;
 926
 927         /* fix ourselves to that channel now already */
 928         if (params->channel_fixed) {
 929                 sdata->local->oper_channel = params->channel;
 930                 WARN_ON(!ieee80211_set_channel_type(sdata->local, sdata,
 931                                                     NL80211_CHAN_NO_HT));
 932         }
 933
 934         if (params->ie) {
 935                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 936                                            GFP_KERNEL);
 937                 if (sdata->u.ibss.ie)
 938                         sdata->u.ibss.ie_len = params->ie_len;
 939         }
 940
 941         sdata->u.ibss.skb = skb;
 942         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 943         sdata->u.ibss.ibss_join_req = jiffies;
 944
 945         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 946         sdata->u.ibss.ssid_len = params->ssid_len;
 947
 948         mutex_unlock(&sdata->u.ibss.mtx);
 949
 950         mutex_lock(&sdata->local->mtx);
 951         ieee80211_recalc_idle(sdata->local);
 952         mutex_unlock(&sdata->local->mtx);
 953
 954         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 955
 956         return 0;
 957 }
 958
 959 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 960 {
 961         struct sk_buff *skb;
 962         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 963         struct ieee80211_local *local = sdata->local;
 964         struct cfg80211_bss *cbss;
 965         u16 capability;
 966         int active_ibss;
 967
 968         mutex_lock(&sdata->u.ibss.mtx);
 969
 970         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 971         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
 972         sdata->u.ibss.ssid_len = 0;
 973
 974         active_ibss = ieee80211_sta_active_ibss(sdata);
 975
 976         if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
 977                 capability = WLAN_CAPABILITY_IBSS;
 978
 979                 if (ifibss->privacy)
 980                         capability |= WLAN_CAPABILITY_PRIVACY;
 981
 982                 cbss = cfg80211_get_bss(local->hw.wiphy, ifibss->channel,
 983                                         ifibss->bssid, ifibss->ssid,
 984                                         ifibss->ssid_len, WLAN_CAPABILITY_IBSS |
 985                                         WLAN_CAPABILITY_PRIVACY,
 986                                         capability);
 987
 988                 if (cbss) {
 989                         cfg80211_unlink_bss(local->hw.wiphy, cbss);
 990                         cfg80211_put_bss(cbss);
 991                 }
 992         }
 993
 994         sta_info_flush(sdata->local, sdata);
 995         netif_carrier_off(sdata->dev);
 996
 997         /* remove beacon */
 998         kfree(sdata->u.ibss.ie);
 999         skb = rcu_dereference_protected(sdata->u.ibss.presp,
1000                                         lockdep_is_held(&sdata->u.ibss.mtx));
1001         RCU_INIT_POINTER(sdata->u.ibss.presp, NULL);
1002         sdata->vif.bss_conf.ibss_joined = false;
1003         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
1004                                                 BSS_CHANGED_IBSS);
1005         synchronize_rcu();
1006         kfree_skb(skb);
1007
1008         skb_queue_purge(&sdata->skb_queue);
1009
1010         del_timer_sync(&sdata->u.ibss.timer);
1011
1012         mutex_unlock(&sdata->u.ibss.mtx);
1013
1014         mutex_lock(&local->mtx);
1015         ieee80211_recalc_idle(sdata->local);
1016         mutex_unlock(&local->mtx);
1017
1018         return 0;
1019 }