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
  77         if (local->ops->reset_tsf) {
  78                 /* Reset own TSF to allow time synchronization work. */
  79                 local->ops->reset_tsf(local_to_hw(local));
  80         }
  81
  82         skb = ifibss->skb;
  83         rcu_assign_pointer(ifibss->presp, NULL);
  84         synchronize_rcu();
  85         skb->data = skb->head;
  86         skb->len = 0;
  87         skb_reset_tail_pointer(skb);
  88         skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
  89
  90         if (memcmp(ifibss->bssid, bssid, ETH_ALEN))
  91                 sta_info_flush(sdata->local, sdata);
  92
  93         memcpy(ifibss->bssid, bssid, ETH_ALEN);
  94
  95         local->hw.conf.beacon_int = beacon_int >= 10 ? beacon_int : 10;
  96
  97         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
  98
  99         ieee80211_if_config(sdata, IEEE80211_IFCC_BSSID);
 100
 101         local->oper_channel = chan;
 102         local->oper_channel_type = NL80211_CHAN_NO_HT;
 103         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 104         sband = local->hw.wiphy->bands[chan->band];
 105
 106         /* Build IBSS probe response */
 107         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 108         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 109         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 110                                           IEEE80211_STYPE_PROBE_RESP);
 111         memset(mgmt->da, 0xff, ETH_ALEN);
 112         memcpy(mgmt->sa, sdata->dev->dev_addr, ETH_ALEN);
 113         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 114         mgmt->u.beacon.beacon_int = cpu_to_le16(local->hw.conf.beacon_int);
 115         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 116         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 117
 118         pos = skb_put(skb, 2 + ifibss->ssid_len);
 119         *pos++ = WLAN_EID_SSID;
 120         *pos++ = ifibss->ssid_len;
 121         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 122
 123         rates = supp_rates_len;
 124         if (rates > 8)
 125                 rates = 8;
 126         pos = skb_put(skb, 2 + rates);
 127         *pos++ = WLAN_EID_SUPP_RATES;
 128         *pos++ = rates;
 129         memcpy(pos, supp_rates, rates);
 130
 131         if (sband->band == IEEE80211_BAND_2GHZ) {
 132                 pos = skb_put(skb, 2 + 1);
 133                 *pos++ = WLAN_EID_DS_PARAMS;
 134                 *pos++ = 1;
 135                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 136         }
 137
 138         pos = skb_put(skb, 2 + 2);
 139         *pos++ = WLAN_EID_IBSS_PARAMS;
 140         *pos++ = 2;
 141         /* FIX: set ATIM window based on scan results */
 142         *pos++ = 0;
 143         *pos++ = 0;
 144
 145         if (supp_rates_len > 8) {
 146                 rates = supp_rates_len - 8;
 147                 pos = skb_put(skb, 2 + rates);
 148                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 149                 *pos++ = rates;
 150                 memcpy(pos, &supp_rates[8], rates);
 151         }
 152
 153         if (ifibss->ie_len)
 154                 memcpy(skb_put(skb, ifibss->ie_len),
 155                        ifibss->ie, ifibss->ie_len);
 156
 157         rcu_assign_pointer(ifibss->presp, skb);
 158
 159         ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON |
 160                                    IEEE80211_IFCC_BEACON_ENABLED);
 161
 162         rates = 0;
 163         for (i = 0; i < supp_rates_len; i++) {
 164                 int bitrate = (supp_rates[i] & 0x7f) * 5;
 165                 for (j = 0; j < sband->n_bitrates; j++)
 166                         if (sband->bitrates[j].bitrate == bitrate)
 167                                 rates |= BIT(j);
 168         }
 169
 170         ieee80211_sta_def_wmm_params(sdata, supp_rates_len, supp_rates);
 171
 172         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 173         mod_timer(&ifibss->timer,
 174                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 175
 176         cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 177                                   mgmt, skb->len, 0, GFP_KERNEL);
 178         cfg80211_ibss_joined(sdata->dev, ifibss->bssid, GFP_KERNEL);
 179 }
 180
 181 static void ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
 182                                     struct ieee80211_bss *bss)
 183 {
 184         __ieee80211_sta_join_ibss(sdata, bss->cbss.bssid,
 185                                   bss->cbss.beacon_interval,
 186                                   bss->cbss.channel,
 187                                   bss->supp_rates_len, bss->supp_rates,
 188                                   bss->cbss.capability,
 189                                   bss->cbss.tsf);
 190 }
 191
 192 static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
 193                                   struct ieee80211_mgmt *mgmt,
 194                                   size_t len,
 195                                   struct ieee80211_rx_status *rx_status,
 196                                   struct ieee802_11_elems *elems,
 197                                   bool beacon)
 198 {
 199         struct ieee80211_local *local = sdata->local;
 200         int freq;
 201         struct ieee80211_bss *bss;
 202         struct sta_info *sta;
 203         struct ieee80211_channel *channel;
 204         u64 beacon_timestamp, rx_timestamp;
 205         u32 supp_rates = 0;
 206         enum ieee80211_band band = rx_status->band;
 207
 208         if (elems->ds_params && elems->ds_params_len == 1)
 209                 freq = ieee80211_channel_to_frequency(elems->ds_params[0]);
 210         else
 211                 freq = rx_status->freq;
 212
 213         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 214
 215         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 216                 return;
 217
 218         if (sdata->vif.type == NL80211_IFTYPE_ADHOC && elems->supp_rates &&
 219             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 220                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 221
 222                 rcu_read_lock();
 223
 224                 sta = sta_info_get(local, mgmt->sa);
 225                 if (sta) {
 226                         u32 prev_rates;
 227
 228                         prev_rates = sta->sta.supp_rates[band];
 229                         /* make sure mandatory rates are always added */
 230                         sta->sta.supp_rates[band] = supp_rates |
 231                                 ieee80211_mandatory_rates(local, band);
 232
 233 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 234                         if (sta->sta.supp_rates[band] != prev_rates)
 235                                 printk(KERN_DEBUG "%s: updated supp_rates set "
 236                                     "for %pM based on beacon info (0x%llx | "
 237                                     "0x%llx -> 0x%llx)\n",
 238                                     sdata->dev->name,
 239                                     sta->sta.addr,
 240                                     (unsigned long long) prev_rates,
 241                                     (unsigned long long) supp_rates,
 242                                     (unsigned long long) sta->sta.supp_rates[band]);
 243 #endif
 244                 } else
 245                         ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
 246
 247                 rcu_read_unlock();
 248         }
 249
 250         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 251                                         channel, beacon);
 252         if (!bss)
 253                 return;
 254
 255         /* was just updated in ieee80211_bss_info_update */
 256         beacon_timestamp = bss->cbss.tsf;
 257
 258         /* check if we need to merge IBSS */
 259
 260         /* merge only on beacons (???) */
 261         if (!beacon)
 262                 goto put_bss;
 263
 264         /* we use a fixed BSSID */
 265         if (sdata->u.ibss.bssid)
 266                 goto put_bss;
 267
 268         /* not an IBSS */
 269         if (!(bss->cbss.capability & WLAN_CAPABILITY_IBSS))
 270                 goto put_bss;
 271
 272         /* different channel */
 273         if (bss->cbss.channel != local->oper_channel)
 274                 goto put_bss;
 275
 276         /* different SSID */
 277         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 278             memcmp(elems->ssid, sdata->u.ibss.ssid,
 279                                 sdata->u.ibss.ssid_len))
 280                 goto put_bss;
 281
 282         /* same BSSID */
 283         if (memcmp(bss->cbss.bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 284                 goto put_bss;
 285
 286         if (rx_status->flag & RX_FLAG_TSFT) {
 287                 /*
 288                  * For correct IBSS merging we need mactime; since mactime is
 289                  * defined as the time the first data symbol of the frame hits
 290                  * the PHY, and the timestamp of the beacon is defined as "the
 291                  * time that the data symbol containing the first bit of the
 292                  * timestamp is transmitted to the PHY plus the transmitting
 293                  * STA's delays through its local PHY from the MAC-PHY
 294                  * interface to its interface with the WM" (802.11 11.1.2)
 295                  * - equals the time this bit arrives at the receiver - we have
 296                  * to take into account the offset between the two.
 297                  *
 298                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 299                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 300                  */
 301                 int rate;
 302
 303                 if (rx_status->flag & RX_FLAG_HT)
 304                         rate = 65; /* TODO: HT rates */
 305                 else
 306                         rate = local->hw.wiphy->bands[band]->
 307                                 bitrates[rx_status->rate_idx].bitrate;
 308
 309                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 310         } else if (local && local->ops && local->ops->get_tsf)
 311                 /* second best option: get current TSF */
 312                 rx_timestamp = local->ops->get_tsf(local_to_hw(local));
 313         else
 314                 /* can't merge without knowing the TSF */
 315                 rx_timestamp = -1LLU;
 316
 317 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 318         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 319                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 320                mgmt->sa, mgmt->bssid,
 321                (unsigned long long)rx_timestamp,
 322                (unsigned long long)beacon_timestamp,
 323                (unsigned long long)(rx_timestamp - beacon_timestamp),
 324                jiffies);
 325 #endif
 326
 327         /* give slow hardware some time to do the TSF sync */
 328         if (rx_timestamp < IEEE80211_IBSS_MERGE_DELAY)
 329                 goto put_bss;
 330
 331         if (beacon_timestamp > rx_timestamp) {
 332 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 333                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 334                        "local TSF - IBSS merge with BSSID %pM\n",
 335                        sdata->dev->name, mgmt->bssid);
 336 #endif
 337                 ieee80211_sta_join_ibss(sdata, bss);
 338                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa, supp_rates);
 339         }
 340
 341  put_bss:
 342         ieee80211_rx_bss_put(local, bss);
 343 }
 344
 345 /*
 346  * Add a new IBSS station, will also be called by the RX code when,
 347  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 348  * must be callable in atomic context.
 349  */
 350 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 351                                         u8 *bssid,u8 *addr, u32 supp_rates)
 352 {
 353         struct ieee80211_local *local = sdata->local;
 354         struct sta_info *sta;
 355         int band = local->hw.conf.channel->band;
 356
 357         /*
 358          * XXX: Consider removing the least recently used entry and
 359          *      allow new one to be added.
 360          */
 361         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 362                 if (net_ratelimit())
 363                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 364                                sdata->dev->name, addr);
 365                 return NULL;
 366         }
 367
 368         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 369                 return NULL;
 370
 371 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 372         printk(KERN_DEBUG "%s: Adding new IBSS station %pM (dev=%s)\n",
 373                wiphy_name(local->hw.wiphy), addr, sdata->dev->name);
 374 #endif
 375
 376         sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
 377         if (!sta)
 378                 return NULL;
 379
 380         set_sta_flags(sta, WLAN_STA_AUTHORIZED);
 381
 382         /* make sure mandatory rates are always added */
 383         sta->sta.supp_rates[band] = supp_rates |
 384                         ieee80211_mandatory_rates(local, band);
 385
 386         rate_control_rate_init(sta);
 387
 388         if (sta_info_insert(sta))
 389                 return NULL;
 390
 391         return sta;
 392 }
 393
 394 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 395 {
 396         struct ieee80211_local *local = sdata->local;
 397         int active = 0;
 398         struct sta_info *sta;
 399
 400         rcu_read_lock();
 401
 402         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 403                 if (sta->sdata == sdata &&
 404                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 405                                jiffies)) {
 406                         active++;
 407                         break;
 408                 }
 409         }
 410
 411         rcu_read_unlock();
 412
 413         return active;
 414 }
 415
 416
 417 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 418 {
 419         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 420
 421         mod_timer(&ifibss->timer,
 422                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 423
 424         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 425
 426         if (ieee80211_sta_active_ibss(sdata))
 427                 return;
 428
 429         if (ifibss->fixed_channel)
 430                 return;
 431
 432         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 433                "IBSS networks with same SSID (merge)\n", sdata->dev->name);
 434
 435         /* XXX maybe racy? */
 436         if (sdata->local->scan_req)
 437                 return;
 438
 439         memcpy(sdata->local->int_scan_req.ssids[0].ssid,
 440                ifibss->ssid, IEEE80211_MAX_SSID_LEN);
 441         sdata->local->int_scan_req.ssids[0].ssid_len = ifibss->ssid_len;
 442         ieee80211_request_scan(sdata, &sdata->local->int_scan_req);
 443 }
 444
 445 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 446 {
 447         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 448         struct ieee80211_local *local = sdata->local;
 449         struct ieee80211_supported_band *sband;
 450         u8 *pos;
 451         u8 bssid[ETH_ALEN];
 452         u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
 453         u16 capability;
 454         int i;
 455
 456         if (ifibss->fixed_bssid) {
 457                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 458         } else {
 459                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 460                  * own MAC address to make sure that devices that do not have proper
 461                  * random number generator get different BSSID. */
 462                 get_random_bytes(bssid, ETH_ALEN);
 463                 for (i = 0; i < ETH_ALEN; i++)
 464                         bssid[i] ^= sdata->dev->dev_addr[i];
 465                 bssid[0] &= ~0x01;
 466                 bssid[0] |= 0x02;
 467         }
 468
 469         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 470                sdata->dev->name, bssid);
 471
 472         sband = local->hw.wiphy->bands[ifibss->channel->band];
 473
 474         if (local->hw.conf.beacon_int == 0)
 475                 local->hw.conf.beacon_int = 100;
 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, local->hw.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                 /* XXX maybe racy? */
 556                 if (local->scan_req)
 557                         return;
 558
 559                 memcpy(local->int_scan_req.ssids[0].ssid,
 560                        ifibss->ssid, IEEE80211_MAX_SSID_LEN);
 561                 local->int_scan_req.ssids[0].ssid_len =
 562                         ifibss->ssid_len;
 563                 ieee80211_request_scan(sdata, &local->int_scan_req);
 564         } else if (ifibss->state != IEEE80211_IBSS_MLME_JOINED) {
 565                 int interval = IEEE80211_SCAN_INTERVAL;
 566
 567                 if (time_after(jiffies, ifibss->ibss_join_req +
 568                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 569                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 570                                 ieee80211_sta_create_ibss(sdata);
 571                                 return;
 572                         }
 573                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 574                                " %d MHz\n", sdata->dev->name,
 575                                local->hw.conf.channel->center_freq);
 576
 577                         /* No IBSS found - decrease scan interval and continue
 578                          * scanning. */
 579                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 580                 }
 581
 582                 ifibss->state = IEEE80211_IBSS_MLME_SEARCH;
 583                 mod_timer(&ifibss->timer,
 584                           round_jiffies(jiffies + interval));
 585         }
 586 }
 587
 588 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 589                                         struct ieee80211_mgmt *mgmt,
 590                                         size_t len)
 591 {
 592         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 593         struct ieee80211_local *local = sdata->local;
 594         int tx_last_beacon;
 595         struct sk_buff *skb;
 596         struct ieee80211_mgmt *resp;
 597         u8 *pos, *end;
 598
 599         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 600             len < 24 + 2 || !ifibss->presp)
 601                 return;
 602
 603         if (local->ops->tx_last_beacon)
 604                 tx_last_beacon = local->ops->tx_last_beacon(local_to_hw(local));
 605         else
 606                 tx_last_beacon = 1;
 607
 608 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 609         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 610                " (tx_last_beacon=%d)\n",
 611                sdata->dev->name, mgmt->sa, mgmt->da,
 612                mgmt->bssid, tx_last_beacon);
 613 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 614
 615         if (!tx_last_beacon)
 616                 return;
 617
 618         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 619             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 620                 return;
 621
 622         end = ((u8 *) mgmt) + len;
 623         pos = mgmt->u.probe_req.variable;
 624         if (pos[0] != WLAN_EID_SSID ||
 625             pos + 2 + pos[1] > end) {
 626 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 627                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 628                        "from %pM\n",
 629                        sdata->dev->name, mgmt->sa);
 630 #endif
 631                 return;
 632         }
 633         if (pos[1] != 0 &&
 634             (pos[1] != ifibss->ssid_len ||
 635              !memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 636                 /* Ignore ProbeReq for foreign SSID */
 637                 return;
 638         }
 639
 640         /* Reply with ProbeResp */
 641         skb = skb_copy(ifibss->presp, GFP_KERNEL);
 642         if (!skb)
 643                 return;
 644
 645         resp = (struct ieee80211_mgmt *) skb->data;
 646         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 647 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 648         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 649                sdata->dev->name, resp->da);
 650 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 651         ieee80211_tx_skb(sdata, skb, 0);
 652 }
 653
 654 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 655                                          struct ieee80211_mgmt *mgmt,
 656                                          size_t len,
 657                                          struct ieee80211_rx_status *rx_status)
 658 {
 659         size_t baselen;
 660         struct ieee802_11_elems elems;
 661
 662         if (memcmp(mgmt->da, sdata->dev->dev_addr, ETH_ALEN))
 663                 return; /* ignore ProbeResp to foreign address */
 664
 665         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 666         if (baselen > len)
 667                 return;
 668
 669         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 670                                 &elems);
 671
 672         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 673 }
 674
 675 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 676                                      struct ieee80211_mgmt *mgmt,
 677                                      size_t len,
 678                                      struct ieee80211_rx_status *rx_status)
 679 {
 680         size_t baselen;
 681         struct ieee802_11_elems elems;
 682
 683         /* Process beacon from the current BSS */
 684         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 685         if (baselen > len)
 686                 return;
 687
 688         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 689
 690         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 691 }
 692
 693 static void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 694                                           struct sk_buff *skb)
 695 {
 696         struct ieee80211_rx_status *rx_status;
 697         struct ieee80211_mgmt *mgmt;
 698         u16 fc;
 699
 700         rx_status = (struct ieee80211_rx_status *) skb->cb;
 701         mgmt = (struct ieee80211_mgmt *) skb->data;
 702         fc = le16_to_cpu(mgmt->frame_control);
 703
 704         switch (fc & IEEE80211_FCTL_STYPE) {
 705         case IEEE80211_STYPE_PROBE_REQ:
 706                 ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
 707                 break;
 708         case IEEE80211_STYPE_PROBE_RESP:
 709                 ieee80211_rx_mgmt_probe_resp(sdata, mgmt, skb->len,
 710                                              rx_status);
 711                 break;
 712         case IEEE80211_STYPE_BEACON:
 713                 ieee80211_rx_mgmt_beacon(sdata, mgmt, skb->len,
 714                                          rx_status);
 715                 break;
 716         case IEEE80211_STYPE_AUTH:
 717                 ieee80211_rx_mgmt_auth_ibss(sdata, mgmt, skb->len);
 718                 break;
 719         }
 720
 721         kfree_skb(skb);
 722 }
 723
 724 static void ieee80211_ibss_work(struct work_struct *work)
 725 {
 726         struct ieee80211_sub_if_data *sdata =
 727                 container_of(work, struct ieee80211_sub_if_data, u.ibss.work);
 728         struct ieee80211_local *local = sdata->local;
 729         struct ieee80211_if_ibss *ifibss;
 730         struct sk_buff *skb;
 731
 732         if (!netif_running(sdata->dev))
 733                 return;
 734
 735         if (local->sw_scanning || local->hw_scanning)
 736                 return;
 737
 738         if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_ADHOC))
 739                 return;
 740         ifibss = &sdata->u.ibss;
 741
 742         while ((skb = skb_dequeue(&ifibss->skb_queue)))
 743                 ieee80211_ibss_rx_queued_mgmt(sdata, skb);
 744
 745         if (!test_and_clear_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request))
 746                 return;
 747
 748         switch (ifibss->state) {
 749         case IEEE80211_IBSS_MLME_SEARCH:
 750                 ieee80211_sta_find_ibss(sdata);
 751                 break;
 752         case IEEE80211_IBSS_MLME_JOINED:
 753                 ieee80211_sta_merge_ibss(sdata);
 754                 break;
 755         default:
 756                 WARN_ON(1);
 757                 break;
 758         }
 759 }
 760
 761 static void ieee80211_ibss_timer(unsigned long data)
 762 {
 763         struct ieee80211_sub_if_data *sdata =
 764                 (struct ieee80211_sub_if_data *) data;
 765         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 766         struct ieee80211_local *local = sdata->local;
 767
 768         set_bit(IEEE80211_IBSS_REQ_RUN, &ifibss->request);
 769         queue_work(local->hw.workqueue, &ifibss->work);
 770 }
 771
 772 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 773 {
 774         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 775
 776         INIT_WORK(&ifibss->work, ieee80211_ibss_work);
 777         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 778                     (unsigned long) sdata);
 779         skb_queue_head_init(&ifibss->skb_queue);
 780 }
 781
 782 /* scan finished notification */
 783 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 784 {
 785         struct ieee80211_sub_if_data *sdata;
 786
 787         rcu_read_lock();
 788         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 789                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 790                         continue;
 791                 sdata->u.ibss.last_scan_completed = jiffies;
 792                 ieee80211_sta_find_ibss(sdata);
 793         }
 794         rcu_read_unlock();
 795 }
 796
 797 ieee80211_rx_result
 798 ieee80211_ibss_rx_mgmt(struct ieee80211_sub_if_data *sdata, struct sk_buff *skb,
 799                        struct ieee80211_rx_status *rx_status)
 800 {
 801         struct ieee80211_local *local = sdata->local;
 802         struct ieee80211_mgmt *mgmt;
 803         u16 fc;
 804
 805         if (skb->len < 24)
 806                 return RX_DROP_MONITOR;
 807
 808         mgmt = (struct ieee80211_mgmt *) skb->data;
 809         fc = le16_to_cpu(mgmt->frame_control);
 810
 811         switch (fc & IEEE80211_FCTL_STYPE) {
 812         case IEEE80211_STYPE_PROBE_RESP:
 813         case IEEE80211_STYPE_BEACON:
 814                 memcpy(skb->cb, rx_status, sizeof(*rx_status));
 815         case IEEE80211_STYPE_PROBE_REQ:
 816         case IEEE80211_STYPE_AUTH:
 817                 skb_queue_tail(&sdata->u.ibss.skb_queue, skb);
 818                 queue_work(local->hw.workqueue, &sdata->u.ibss.work);
 819                 return RX_QUEUED;
 820         }
 821
 822         return RX_DROP_MONITOR;
 823 }
 824
 825 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 826                         struct cfg80211_ibss_params *params)
 827 {
 828         struct sk_buff *skb;
 829
 830         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 831         sdata->u.ibss.ssid_len = params->ssid_len;
 832
 833         if (params->bssid) {
 834                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 835                 sdata->u.ibss.fixed_bssid = true;
 836         } else
 837                 sdata->u.ibss.fixed_bssid = false;
 838
 839         sdata->u.ibss.channel = params->channel;
 840         sdata->u.ibss.fixed_channel = params->channel_fixed;
 841
 842         if (params->ie) {
 843                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 844                                            GFP_KERNEL);
 845                 if (sdata->u.ibss.ie)
 846                         sdata->u.ibss.ie_len = params->ie_len;
 847         }
 848
 849         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 850                             36 /* bitrates */ +
 851                             34 /* SSID */ +
 852                             3  /* DS params */ +
 853                             4  /* IBSS params */ +
 854                             params->ie_len);
 855         if (!skb)
 856                 return -ENOMEM;
 857
 858         sdata->u.ibss.skb = skb;
 859         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 860         sdata->u.ibss.ibss_join_req = jiffies;
 861
 862         set_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 863         queue_work(sdata->local->hw.workqueue, &sdata->u.ibss.work);
 864
 865         return 0;
 866 }
 867
 868 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 869 {
 870         struct sk_buff *skb;
 871
 872         del_timer_sync(&sdata->u.ibss.timer);
 873         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 874         cancel_work_sync(&sdata->u.ibss.work);
 875         clear_bit(IEEE80211_IBSS_REQ_RUN, &sdata->u.ibss.request);
 876
 877         sta_info_flush(sdata->local, sdata);
 878
 879         /* remove beacon */
 880         kfree(sdata->u.ibss.ie);
 881         skb = sdata->u.ibss.presp;
 882         rcu_assign_pointer(sdata->u.ibss.presp, NULL);
 883         ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED);
 884         synchronize_rcu();
 885         kfree_skb(skb);
 886
 887         skb_queue_purge(&sdata->u.ibss.skb_queue);
 888         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
 889
 890         return 0;
 891 }