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_MERGE_DELAY 0x400000
  35 #define IEEE80211_IBSS_INACTIVITY_LIMIT (60 * HZ)
  36
  37 #define IEEE80211_IBSS_MAX_STA_ENTRIES 128
  38
  39
  40 static void ieee80211_rx_mgmt_auth_ibss(struct ieee80211_sub_if_data *sdata,
  41                                         struct ieee80211_mgmt *mgmt,
  42                                         size_t len)
  43 {
  44         u16 auth_alg, auth_transaction, status_code;
  45
  46         lockdep_assert_held(&sdata->u.ibss.mtx);
  47
  48         if (len < 24 + 6)
  49                 return;
  50
  51         auth_alg = le16_to_cpu(mgmt->u.auth.auth_alg);
  52         auth_transaction = le16_to_cpu(mgmt->u.auth.auth_transaction);
  53         status_code = le16_to_cpu(mgmt->u.auth.status_code);
  54
  55         /*
  56          * IEEE 802.11 standard does not require authentication in IBSS
  57          * networks and most implementations do not seem to use it.
  58          * However, try to reply to authentication attempts if someone
  59          * has actually implemented this.
  60          */
  61         if (auth_alg == WLAN_AUTH_OPEN && auth_transaction == 1)
  62                 ieee80211_send_auth(sdata, 2, WLAN_AUTH_OPEN, NULL, 0,
  63                                     sdata->u.ibss.bssid, NULL, 0, 0);
  64 }
  65
  66 static void __ieee80211_sta_join_ibss(struct ieee80211_sub_if_data *sdata,
  67                                       const u8 *bssid, const int beacon_int,
  68                                       struct ieee80211_channel *chan,
  69                                       const u32 basic_rates,
  70                                       const u16 capability, u64 tsf)
  71 {
  72         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
  73         struct ieee80211_local *local = sdata->local;
  74         int rates, i;
  75         struct sk_buff *skb;
  76         struct ieee80211_mgmt *mgmt;
  77         u8 *pos;
  78         struct ieee80211_supported_band *sband;
  79         struct cfg80211_bss *bss;
  80         u32 bss_change;
  81         u8 supp_rates[IEEE80211_MAX_SUPP_RATES];
  82
  83         lockdep_assert_held(&ifibss->mtx);
  84
  85         /* Reset own TSF to allow time synchronization work. */
  86         drv_reset_tsf(local);
  87
  88         skb = ifibss->skb;
  89         rcu_assign_pointer(ifibss->presp, NULL);
  90         synchronize_rcu();
  91         skb->data = skb->head;
  92         skb->len = 0;
  93         skb_reset_tail_pointer(skb);
  94         skb_reserve(skb, sdata->local->hw.extra_tx_headroom);
  95
  96         if (memcmp(ifibss->bssid, bssid, ETH_ALEN))
  97                 sta_info_flush(sdata->local, sdata);
  98
  99         /* if merging, indicate to driver that we leave the old IBSS */
 100         if (sdata->vif.bss_conf.ibss_joined) {
 101                 sdata->vif.bss_conf.ibss_joined = false;
 102                 ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_IBSS);
 103         }
 104
 105         memcpy(ifibss->bssid, bssid, ETH_ALEN);
 106
 107         sdata->drop_unencrypted = capability & WLAN_CAPABILITY_PRIVACY ? 1 : 0;
 108
 109         local->oper_channel = chan;
 110         WARN_ON(!ieee80211_set_channel_type(local, sdata, NL80211_CHAN_NO_HT));
 111         ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
 112
 113         sband = local->hw.wiphy->bands[chan->band];
 114
 115         /* build supported rates array */
 116         pos = supp_rates;
 117         for (i = 0; i < sband->n_bitrates; i++) {
 118                 int rate = sband->bitrates[i].bitrate;
 119                 u8 basic = 0;
 120                 if (basic_rates & BIT(i))
 121                         basic = 0x80;
 122                 *pos++ = basic | (u8) (rate / 5);
 123         }
 124
 125         /* Build IBSS probe response */
 126         mgmt = (void *) skb_put(skb, 24 + sizeof(mgmt->u.beacon));
 127         memset(mgmt, 0, 24 + sizeof(mgmt->u.beacon));
 128         mgmt->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
 129                                           IEEE80211_STYPE_PROBE_RESP);
 130         memset(mgmt->da, 0xff, ETH_ALEN);
 131         memcpy(mgmt->sa, sdata->vif.addr, ETH_ALEN);
 132         memcpy(mgmt->bssid, ifibss->bssid, ETH_ALEN);
 133         mgmt->u.beacon.beacon_int = cpu_to_le16(beacon_int);
 134         mgmt->u.beacon.timestamp = cpu_to_le64(tsf);
 135         mgmt->u.beacon.capab_info = cpu_to_le16(capability);
 136
 137         pos = skb_put(skb, 2 + ifibss->ssid_len);
 138         *pos++ = WLAN_EID_SSID;
 139         *pos++ = ifibss->ssid_len;
 140         memcpy(pos, ifibss->ssid, ifibss->ssid_len);
 141
 142         rates = sband->n_bitrates;
 143         if (rates > 8)
 144                 rates = 8;
 145         pos = skb_put(skb, 2 + rates);
 146         *pos++ = WLAN_EID_SUPP_RATES;
 147         *pos++ = rates;
 148         memcpy(pos, supp_rates, rates);
 149
 150         if (sband->band == IEEE80211_BAND_2GHZ) {
 151                 pos = skb_put(skb, 2 + 1);
 152                 *pos++ = WLAN_EID_DS_PARAMS;
 153                 *pos++ = 1;
 154                 *pos++ = ieee80211_frequency_to_channel(chan->center_freq);
 155         }
 156
 157         pos = skb_put(skb, 2 + 2);
 158         *pos++ = WLAN_EID_IBSS_PARAMS;
 159         *pos++ = 2;
 160         /* FIX: set ATIM window based on scan results */
 161         *pos++ = 0;
 162         *pos++ = 0;
 163
 164         if (sband->n_bitrates > 8) {
 165                 rates = sband->n_bitrates - 8;
 166                 pos = skb_put(skb, 2 + rates);
 167                 *pos++ = WLAN_EID_EXT_SUPP_RATES;
 168                 *pos++ = rates;
 169                 memcpy(pos, &supp_rates[8], rates);
 170         }
 171
 172         if (ifibss->ie_len)
 173                 memcpy(skb_put(skb, ifibss->ie_len),
 174                        ifibss->ie, ifibss->ie_len);
 175
 176         if (local->hw.queues >= 4) {
 177                 pos = skb_put(skb, 9);
 178                 *pos++ = WLAN_EID_VENDOR_SPECIFIC;
 179                 *pos++ = 7; /* len */
 180                 *pos++ = 0x00; /* Microsoft OUI 00:50:F2 */
 181                 *pos++ = 0x50;
 182                 *pos++ = 0xf2;
 183                 *pos++ = 2; /* WME */
 184                 *pos++ = 0; /* WME info */
 185                 *pos++ = 1; /* WME ver */
 186                 *pos++ = 0; /* U-APSD no in use */
 187         }
 188
 189         rcu_assign_pointer(ifibss->presp, skb);
 190
 191         sdata->vif.bss_conf.beacon_int = beacon_int;
 192         sdata->vif.bss_conf.basic_rates = basic_rates;
 193         bss_change = BSS_CHANGED_BEACON_INT;
 194         bss_change |= ieee80211_reset_erp_info(sdata);
 195         bss_change |= BSS_CHANGED_BSSID;
 196         bss_change |= BSS_CHANGED_BEACON;
 197         bss_change |= BSS_CHANGED_BEACON_ENABLED;
 198         bss_change |= BSS_CHANGED_BASIC_RATES;
 199         bss_change |= BSS_CHANGED_IBSS;
 200         sdata->vif.bss_conf.ibss_joined = true;
 201         ieee80211_bss_info_change_notify(sdata, bss_change);
 202
 203         ieee80211_sta_def_wmm_params(sdata, sband->n_bitrates, supp_rates);
 204
 205         ifibss->state = IEEE80211_IBSS_MLME_JOINED;
 206         mod_timer(&ifibss->timer,
 207                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 208
 209         bss = cfg80211_inform_bss_frame(local->hw.wiphy, local->hw.conf.channel,
 210                                         mgmt, skb->len, 0, GFP_KERNEL);
 211         cfg80211_put_bss(bss);
 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         else
 275                 freq = rx_status->freq;
 276
 277         channel = ieee80211_get_channel(local->hw.wiphy, freq);
 278
 279         if (!channel || channel->flags & IEEE80211_CHAN_DISABLED)
 280                 return;
 281
 282         if (sdata->vif.type == NL80211_IFTYPE_ADHOC &&
 283             memcmp(mgmt->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0) {
 284
 285                 rcu_read_lock();
 286                 sta = sta_info_get(sdata, mgmt->sa);
 287
 288                 if (elems->supp_rates) {
 289                         supp_rates = ieee80211_sta_get_rates(local, elems,
 290                                                              band);
 291                         if (sta) {
 292                                 u32 prev_rates;
 293
 294                                 prev_rates = sta->sta.supp_rates[band];
 295                                 /* make sure mandatory rates are always added */
 296                                 sta->sta.supp_rates[band] = supp_rates |
 297                                         ieee80211_mandatory_rates(local, band);
 298
 299                                 if (sta->sta.supp_rates[band] != prev_rates) {
 300 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 301                                         printk(KERN_DEBUG
 302                                                 "%s: updated supp_rates set "
 303                                                 "for %pM based on beacon"
 304                                                 "/probe_resp (0x%x -> 0x%x)\n",
 305                                                 sdata->name, sta->sta.addr,
 306                                                 prev_rates,
 307                                                 sta->sta.supp_rates[band]);
 308 #endif
 309                                         rate_control_rate_init(sta);
 310                                 }
 311                         } else
 312                                 sta = ieee80211_ibss_add_sta(sdata, mgmt->bssid,
 313                                                 mgmt->sa, supp_rates,
 314                                                 GFP_ATOMIC);
 315                 }
 316
 317                 if (sta && elems->wmm_info)
 318                         set_sta_flags(sta, WLAN_STA_WME);
 319
 320                 rcu_read_unlock();
 321         }
 322
 323         bss = ieee80211_bss_info_update(local, rx_status, mgmt, len, elems,
 324                                         channel, beacon);
 325         if (!bss)
 326                 return;
 327
 328         cbss = container_of((void *)bss, struct cfg80211_bss, priv);
 329
 330         /* was just updated in ieee80211_bss_info_update */
 331         beacon_timestamp = cbss->tsf;
 332
 333         /* check if we need to merge IBSS */
 334
 335         /* we use a fixed BSSID */
 336         if (sdata->u.ibss.fixed_bssid)
 337                 goto put_bss;
 338
 339         /* not an IBSS */
 340         if (!(cbss->capability & WLAN_CAPABILITY_IBSS))
 341                 goto put_bss;
 342
 343         /* different channel */
 344         if (cbss->channel != local->oper_channel)
 345                 goto put_bss;
 346
 347         /* different SSID */
 348         if (elems->ssid_len != sdata->u.ibss.ssid_len ||
 349             memcmp(elems->ssid, sdata->u.ibss.ssid,
 350                                 sdata->u.ibss.ssid_len))
 351                 goto put_bss;
 352
 353         /* same BSSID */
 354         if (memcmp(cbss->bssid, sdata->u.ibss.bssid, ETH_ALEN) == 0)
 355                 goto put_bss;
 356
 357         if (rx_status->flag & RX_FLAG_TSFT) {
 358                 /*
 359                  * For correct IBSS merging we need mactime; since mactime is
 360                  * defined as the time the first data symbol of the frame hits
 361                  * the PHY, and the timestamp of the beacon is defined as "the
 362                  * time that the data symbol containing the first bit of the
 363                  * timestamp is transmitted to the PHY plus the transmitting
 364                  * STA's delays through its local PHY from the MAC-PHY
 365                  * interface to its interface with the WM" (802.11 11.1.2)
 366                  * - equals the time this bit arrives at the receiver - we have
 367                  * to take into account the offset between the two.
 368                  *
 369                  * E.g. at 1 MBit that means mactime is 192 usec earlier
 370                  * (=24 bytes * 8 usecs/byte) than the beacon timestamp.
 371                  */
 372                 int rate;
 373
 374                 if (rx_status->flag & RX_FLAG_HT)
 375                         rate = 65; /* TODO: HT rates */
 376                 else
 377                         rate = local->hw.wiphy->bands[band]->
 378                                 bitrates[rx_status->rate_idx].bitrate;
 379
 380                 rx_timestamp = rx_status->mactime + (24 * 8 * 10 / rate);
 381         } else {
 382                 /*
 383                  * second best option: get current TSF
 384                  * (will return -1 if not supported)
 385                  */
 386                 rx_timestamp = drv_get_tsf(local);
 387         }
 388
 389 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 390         printk(KERN_DEBUG "RX beacon SA=%pM BSSID="
 391                "%pM TSF=0x%llx BCN=0x%llx diff=%lld @%lu\n",
 392                mgmt->sa, mgmt->bssid,
 393                (unsigned long long)rx_timestamp,
 394                (unsigned long long)beacon_timestamp,
 395                (unsigned long long)(rx_timestamp - beacon_timestamp),
 396                jiffies);
 397 #endif
 398
 399         /* give slow hardware some time to do the TSF sync */
 400         if (rx_timestamp < IEEE80211_IBSS_MERGE_DELAY)
 401                 goto put_bss;
 402
 403         if (beacon_timestamp > rx_timestamp) {
 404 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 405                 printk(KERN_DEBUG "%s: beacon TSF higher than "
 406                        "local TSF - IBSS merge with BSSID %pM\n",
 407                        sdata->name, mgmt->bssid);
 408 #endif
 409                 ieee80211_sta_join_ibss(sdata, bss);
 410                 supp_rates = ieee80211_sta_get_rates(local, elems, band);
 411                 ieee80211_ibss_add_sta(sdata, mgmt->bssid, mgmt->sa,
 412                                        supp_rates, GFP_KERNEL);
 413         }
 414
 415  put_bss:
 416         ieee80211_rx_bss_put(local, bss);
 417 }
 418
 419 /*
 420  * Add a new IBSS station, will also be called by the RX code when,
 421  * in IBSS mode, receiving a frame from a yet-unknown station, hence
 422  * must be callable in atomic context.
 423  */
 424 struct sta_info *ieee80211_ibss_add_sta(struct ieee80211_sub_if_data *sdata,
 425                                         u8 *bssid,u8 *addr, u32 supp_rates,
 426                                         gfp_t gfp)
 427 {
 428         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 429         struct ieee80211_local *local = sdata->local;
 430         struct sta_info *sta;
 431         int band = local->hw.conf.channel->band;
 432
 433         /*
 434          * XXX: Consider removing the least recently used entry and
 435          *      allow new one to be added.
 436          */
 437         if (local->num_sta >= IEEE80211_IBSS_MAX_STA_ENTRIES) {
 438                 if (net_ratelimit())
 439                         printk(KERN_DEBUG "%s: No room for a new IBSS STA entry %pM\n",
 440                                sdata->name, addr);
 441                 return NULL;
 442         }
 443
 444         if (ifibss->state == IEEE80211_IBSS_MLME_SEARCH)
 445                 return NULL;
 446
 447         if (compare_ether_addr(bssid, sdata->u.ibss.bssid))
 448                 return NULL;
 449
 450 #ifdef CONFIG_MAC80211_VERBOSE_DEBUG
 451         wiphy_debug(local->hw.wiphy, "Adding new IBSS station %pM (dev=%s)\n",
 452                     addr, sdata->name);
 453 #endif
 454
 455         sta = sta_info_alloc(sdata, addr, gfp);
 456         if (!sta)
 457                 return NULL;
 458
 459         sta->last_rx = jiffies;
 460         set_sta_flags(sta, WLAN_STA_AUTHORIZED);
 461
 462         /* make sure mandatory rates are always added */
 463         sta->sta.supp_rates[band] = supp_rates |
 464                         ieee80211_mandatory_rates(local, band);
 465
 466         rate_control_rate_init(sta);
 467
 468         /* If it fails, maybe we raced another insertion? */
 469         if (sta_info_insert(sta))
 470                 return sta_info_get(sdata, addr);
 471         return sta;
 472 }
 473
 474 static int ieee80211_sta_active_ibss(struct ieee80211_sub_if_data *sdata)
 475 {
 476         struct ieee80211_local *local = sdata->local;
 477         int active = 0;
 478         struct sta_info *sta;
 479
 480         lockdep_assert_held(&sdata->u.ibss.mtx);
 481
 482         rcu_read_lock();
 483
 484         list_for_each_entry_rcu(sta, &local->sta_list, list) {
 485                 if (sta->sdata == sdata &&
 486                     time_after(sta->last_rx + IEEE80211_IBSS_MERGE_INTERVAL,
 487                                jiffies)) {
 488                         active++;
 489                         break;
 490                 }
 491         }
 492
 493         rcu_read_unlock();
 494
 495         return active;
 496 }
 497
 498 /*
 499  * This function is called with state == IEEE80211_IBSS_MLME_JOINED
 500  */
 501
 502 static void ieee80211_sta_merge_ibss(struct ieee80211_sub_if_data *sdata)
 503 {
 504         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 505
 506         lockdep_assert_held(&ifibss->mtx);
 507
 508         mod_timer(&ifibss->timer,
 509                   round_jiffies(jiffies + IEEE80211_IBSS_MERGE_INTERVAL));
 510
 511         ieee80211_sta_expire(sdata, IEEE80211_IBSS_INACTIVITY_LIMIT);
 512
 513         if (time_before(jiffies, ifibss->last_scan_completed +
 514                        IEEE80211_IBSS_MERGE_INTERVAL))
 515                 return;
 516
 517         if (ieee80211_sta_active_ibss(sdata))
 518                 return;
 519
 520         if (ifibss->fixed_channel)
 521                 return;
 522
 523         printk(KERN_DEBUG "%s: No active IBSS STAs - trying to scan for other "
 524                "IBSS networks with same SSID (merge)\n", sdata->name);
 525
 526         ieee80211_request_internal_scan(sdata,
 527                         ifibss->ssid, ifibss->ssid_len,
 528                         ifibss->fixed_channel ? ifibss->channel : NULL);
 529 }
 530
 531 static void ieee80211_sta_create_ibss(struct ieee80211_sub_if_data *sdata)
 532 {
 533         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 534         struct ieee80211_local *local = sdata->local;
 535         struct ieee80211_supported_band *sband;
 536         u8 bssid[ETH_ALEN];
 537         u16 capability;
 538         int i;
 539
 540         lockdep_assert_held(&ifibss->mtx);
 541
 542         if (ifibss->fixed_bssid) {
 543                 memcpy(bssid, ifibss->bssid, ETH_ALEN);
 544         } else {
 545                 /* Generate random, not broadcast, locally administered BSSID. Mix in
 546                  * own MAC address to make sure that devices that do not have proper
 547                  * random number generator get different BSSID. */
 548                 get_random_bytes(bssid, ETH_ALEN);
 549                 for (i = 0; i < ETH_ALEN; i++)
 550                         bssid[i] ^= sdata->vif.addr[i];
 551                 bssid[0] &= ~0x01;
 552                 bssid[0] |= 0x02;
 553         }
 554
 555         printk(KERN_DEBUG "%s: Creating new IBSS network, BSSID %pM\n",
 556                sdata->name, bssid);
 557
 558         sband = local->hw.wiphy->bands[ifibss->channel->band];
 559
 560         capability = WLAN_CAPABILITY_IBSS;
 561
 562         if (ifibss->privacy)
 563                 capability |= WLAN_CAPABILITY_PRIVACY;
 564         else
 565                 sdata->drop_unencrypted = 0;
 566
 567         __ieee80211_sta_join_ibss(sdata, bssid, sdata->vif.bss_conf.beacon_int,
 568                                   ifibss->channel, ifibss->basic_rates,
 569                                   capability, 0);
 570 }
 571
 572 /*
 573  * This function is called with state == IEEE80211_IBSS_MLME_SEARCH
 574  */
 575
 576 static void ieee80211_sta_find_ibss(struct ieee80211_sub_if_data *sdata)
 577 {
 578         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 579         struct ieee80211_local *local = sdata->local;
 580         struct cfg80211_bss *cbss;
 581         struct ieee80211_channel *chan = NULL;
 582         const u8 *bssid = NULL;
 583         int active_ibss;
 584         u16 capability;
 585
 586         lockdep_assert_held(&ifibss->mtx);
 587
 588         active_ibss = ieee80211_sta_active_ibss(sdata);
 589 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 590         printk(KERN_DEBUG "%s: sta_find_ibss (active_ibss=%d)\n",
 591                sdata->name, active_ibss);
 592 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 593
 594         if (active_ibss)
 595                 return;
 596
 597         capability = WLAN_CAPABILITY_IBSS;
 598         if (ifibss->privacy)
 599                 capability |= WLAN_CAPABILITY_PRIVACY;
 600         if (ifibss->fixed_bssid)
 601                 bssid = ifibss->bssid;
 602         if (ifibss->fixed_channel)
 603                 chan = ifibss->channel;
 604         if (!is_zero_ether_addr(ifibss->bssid))
 605                 bssid = ifibss->bssid;
 606         cbss = cfg80211_get_bss(local->hw.wiphy, chan, bssid,
 607                                 ifibss->ssid, ifibss->ssid_len,
 608                                 WLAN_CAPABILITY_IBSS | WLAN_CAPABILITY_PRIVACY,
 609                                 capability);
 610
 611         if (cbss) {
 612                 struct ieee80211_bss *bss;
 613
 614                 bss = (void *)cbss->priv;
 615 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 616                 printk(KERN_DEBUG "   sta_find_ibss: selected %pM current "
 617                        "%pM\n", cbss->bssid, ifibss->bssid);
 618 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 619
 620                 printk(KERN_DEBUG "%s: Selected IBSS BSSID %pM"
 621                        " based on configured SSID\n",
 622                        sdata->name, cbss->bssid);
 623
 624                 ieee80211_sta_join_ibss(sdata, bss);
 625                 ieee80211_rx_bss_put(local, bss);
 626                 return;
 627         }
 628
 629 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 630         printk(KERN_DEBUG "   did not try to join ibss\n");
 631 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 632
 633         /* Selected IBSS not found in current scan results - try to scan */
 634         if (time_after(jiffies, ifibss->last_scan_completed +
 635                                         IEEE80211_SCAN_INTERVAL)) {
 636                 printk(KERN_DEBUG "%s: Trigger new scan to find an IBSS to "
 637                        "join\n", sdata->name);
 638
 639                 ieee80211_request_internal_scan(sdata,
 640                                 ifibss->ssid, ifibss->ssid_len,
 641                                 ifibss->fixed_channel ? ifibss->channel : NULL);
 642         } else {
 643                 int interval = IEEE80211_SCAN_INTERVAL;
 644
 645                 if (time_after(jiffies, ifibss->ibss_join_req +
 646                                IEEE80211_IBSS_JOIN_TIMEOUT)) {
 647                         if (!(local->oper_channel->flags & IEEE80211_CHAN_NO_IBSS)) {
 648                                 ieee80211_sta_create_ibss(sdata);
 649                                 return;
 650                         }
 651                         printk(KERN_DEBUG "%s: IBSS not allowed on"
 652                                " %d MHz\n", sdata->name,
 653                                local->hw.conf.channel->center_freq);
 654
 655                         /* No IBSS found - decrease scan interval and continue
 656                          * scanning. */
 657                         interval = IEEE80211_SCAN_INTERVAL_SLOW;
 658                 }
 659
 660                 mod_timer(&ifibss->timer,
 661                           round_jiffies(jiffies + interval));
 662         }
 663 }
 664
 665 static void ieee80211_rx_mgmt_probe_req(struct ieee80211_sub_if_data *sdata,
 666                                         struct ieee80211_mgmt *mgmt,
 667                                         size_t len)
 668 {
 669         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 670         struct ieee80211_local *local = sdata->local;
 671         int tx_last_beacon;
 672         struct sk_buff *skb;
 673         struct ieee80211_mgmt *resp;
 674         u8 *pos, *end;
 675
 676         lockdep_assert_held(&ifibss->mtx);
 677
 678         if (ifibss->state != IEEE80211_IBSS_MLME_JOINED ||
 679             len < 24 + 2 || !ifibss->presp)
 680                 return;
 681
 682         tx_last_beacon = drv_tx_last_beacon(local);
 683
 684 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 685         printk(KERN_DEBUG "%s: RX ProbeReq SA=%pM DA=%pM BSSID=%pM"
 686                " (tx_last_beacon=%d)\n",
 687                sdata->name, mgmt->sa, mgmt->da,
 688                mgmt->bssid, tx_last_beacon);
 689 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 690
 691         if (!tx_last_beacon)
 692                 return;
 693
 694         if (memcmp(mgmt->bssid, ifibss->bssid, ETH_ALEN) != 0 &&
 695             memcmp(mgmt->bssid, "\xff\xff\xff\xff\xff\xff", ETH_ALEN) != 0)
 696                 return;
 697
 698         end = ((u8 *) mgmt) + len;
 699         pos = mgmt->u.probe_req.variable;
 700         if (pos[0] != WLAN_EID_SSID ||
 701             pos + 2 + pos[1] > end) {
 702 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 703                 printk(KERN_DEBUG "%s: Invalid SSID IE in ProbeReq "
 704                        "from %pM\n",
 705                        sdata->name, mgmt->sa);
 706 #endif
 707                 return;
 708         }
 709         if (pos[1] != 0 &&
 710             (pos[1] != ifibss->ssid_len ||
 711              memcmp(pos + 2, ifibss->ssid, ifibss->ssid_len))) {
 712                 /* Ignore ProbeReq for foreign SSID */
 713                 return;
 714         }
 715
 716         /* Reply with ProbeResp */
 717         skb = skb_copy(ifibss->presp, GFP_KERNEL);
 718         if (!skb)
 719                 return;
 720
 721         resp = (struct ieee80211_mgmt *) skb->data;
 722         memcpy(resp->da, mgmt->sa, ETH_ALEN);
 723 #ifdef CONFIG_MAC80211_IBSS_DEBUG
 724         printk(KERN_DEBUG "%s: Sending ProbeResp to %pM\n",
 725                sdata->name, resp->da);
 726 #endif /* CONFIG_MAC80211_IBSS_DEBUG */
 727         IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
 728         ieee80211_tx_skb(sdata, skb);
 729 }
 730
 731 static void ieee80211_rx_mgmt_probe_resp(struct ieee80211_sub_if_data *sdata,
 732                                          struct ieee80211_mgmt *mgmt,
 733                                          size_t len,
 734                                          struct ieee80211_rx_status *rx_status)
 735 {
 736         size_t baselen;
 737         struct ieee802_11_elems elems;
 738
 739         if (memcmp(mgmt->da, sdata->vif.addr, ETH_ALEN))
 740                 return; /* ignore ProbeResp to foreign address */
 741
 742         baselen = (u8 *) mgmt->u.probe_resp.variable - (u8 *) mgmt;
 743         if (baselen > len)
 744                 return;
 745
 746         ieee802_11_parse_elems(mgmt->u.probe_resp.variable, len - baselen,
 747                                 &elems);
 748
 749         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, false);
 750 }
 751
 752 static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata,
 753                                      struct ieee80211_mgmt *mgmt,
 754                                      size_t len,
 755                                      struct ieee80211_rx_status *rx_status)
 756 {
 757         size_t baselen;
 758         struct ieee802_11_elems elems;
 759
 760         /* Process beacon from the current BSS */
 761         baselen = (u8 *) mgmt->u.beacon.variable - (u8 *) mgmt;
 762         if (baselen > len)
 763                 return;
 764
 765         ieee802_11_parse_elems(mgmt->u.beacon.variable, len - baselen, &elems);
 766
 767         ieee80211_rx_bss_info(sdata, mgmt, len, rx_status, &elems, true);
 768 }
 769
 770 void ieee80211_ibss_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata,
 771                                    struct sk_buff *skb)
 772 {
 773         struct ieee80211_rx_status *rx_status;
 774         struct ieee80211_mgmt *mgmt;
 775         u16 fc;
 776
 777         rx_status = IEEE80211_SKB_RXCB(skb);
 778         mgmt = (struct ieee80211_mgmt *) skb->data;
 779         fc = le16_to_cpu(mgmt->frame_control);
 780
 781         mutex_lock(&sdata->u.ibss.mtx);
 782
 783         switch (fc & IEEE80211_FCTL_STYPE) {
 784         case IEEE80211_STYPE_PROBE_REQ:
 785                 ieee80211_rx_mgmt_probe_req(sdata, mgmt, skb->len);
 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         mutex_unlock(&sdata->u.ibss.mtx);
 801 }
 802
 803 void ieee80211_ibss_work(struct ieee80211_sub_if_data *sdata)
 804 {
 805         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 806
 807         mutex_lock(&ifibss->mtx);
 808
 809         /*
 810          * Work could be scheduled after scan or similar
 811          * when we aren't even joined (or trying) with a
 812          * network.
 813          */
 814         if (!ifibss->ssid_len)
 815                 goto out;
 816
 817         switch (ifibss->state) {
 818         case IEEE80211_IBSS_MLME_SEARCH:
 819                 ieee80211_sta_find_ibss(sdata);
 820                 break;
 821         case IEEE80211_IBSS_MLME_JOINED:
 822                 ieee80211_sta_merge_ibss(sdata);
 823                 break;
 824         default:
 825                 WARN_ON(1);
 826                 break;
 827         }
 828
 829  out:
 830         mutex_unlock(&ifibss->mtx);
 831 }
 832
 833 static void ieee80211_ibss_timer(unsigned long data)
 834 {
 835         struct ieee80211_sub_if_data *sdata =
 836                 (struct ieee80211_sub_if_data *) data;
 837         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 838         struct ieee80211_local *local = sdata->local;
 839
 840         if (local->quiescing) {
 841                 ifibss->timer_running = true;
 842                 return;
 843         }
 844
 845         ieee80211_queue_work(&local->hw, &sdata->work);
 846 }
 847
 848 #ifdef CONFIG_PM
 849 void ieee80211_ibss_quiesce(struct ieee80211_sub_if_data *sdata)
 850 {
 851         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 852
 853         if (del_timer_sync(&ifibss->timer))
 854                 ifibss->timer_running = true;
 855 }
 856
 857 void ieee80211_ibss_restart(struct ieee80211_sub_if_data *sdata)
 858 {
 859         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 860
 861         if (ifibss->timer_running) {
 862                 add_timer(&ifibss->timer);
 863                 ifibss->timer_running = false;
 864         }
 865 }
 866 #endif
 867
 868 void ieee80211_ibss_setup_sdata(struct ieee80211_sub_if_data *sdata)
 869 {
 870         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 871
 872         setup_timer(&ifibss->timer, ieee80211_ibss_timer,
 873                     (unsigned long) sdata);
 874         mutex_init(&ifibss->mtx);
 875 }
 876
 877 /* scan finished notification */
 878 void ieee80211_ibss_notify_scan_completed(struct ieee80211_local *local)
 879 {
 880         struct ieee80211_sub_if_data *sdata;
 881
 882         mutex_lock(&local->iflist_mtx);
 883         list_for_each_entry(sdata, &local->interfaces, list) {
 884                 if (!ieee80211_sdata_running(sdata))
 885                         continue;
 886                 if (sdata->vif.type != NL80211_IFTYPE_ADHOC)
 887                         continue;
 888                 sdata->u.ibss.last_scan_completed = jiffies;
 889                 ieee80211_queue_work(&local->hw, &sdata->work);
 890         }
 891         mutex_unlock(&local->iflist_mtx);
 892 }
 893
 894 int ieee80211_ibss_join(struct ieee80211_sub_if_data *sdata,
 895                         struct cfg80211_ibss_params *params)
 896 {
 897         struct sk_buff *skb;
 898
 899         skb = dev_alloc_skb(sdata->local->hw.extra_tx_headroom +
 900                             36 /* bitrates */ +
 901                             34 /* SSID */ +
 902                             3  /* DS params */ +
 903                             4  /* IBSS params */ +
 904                             params->ie_len);
 905         if (!skb)
 906                 return -ENOMEM;
 907
 908         mutex_lock(&sdata->u.ibss.mtx);
 909
 910         if (params->bssid) {
 911                 memcpy(sdata->u.ibss.bssid, params->bssid, ETH_ALEN);
 912                 sdata->u.ibss.fixed_bssid = true;
 913         } else
 914                 sdata->u.ibss.fixed_bssid = false;
 915
 916         sdata->u.ibss.privacy = params->privacy;
 917         sdata->u.ibss.basic_rates = params->basic_rates;
 918
 919         sdata->vif.bss_conf.beacon_int = params->beacon_interval;
 920
 921         sdata->u.ibss.channel = params->channel;
 922         sdata->u.ibss.fixed_channel = params->channel_fixed;
 923
 924         /* fix ourselves to that channel now already */
 925         if (params->channel_fixed) {
 926                 sdata->local->oper_channel = params->channel;
 927                 WARN_ON(!ieee80211_set_channel_type(sdata->local, sdata,
 928                                                     NL80211_CHAN_NO_HT));
 929         }
 930
 931         if (params->ie) {
 932                 sdata->u.ibss.ie = kmemdup(params->ie, params->ie_len,
 933                                            GFP_KERNEL);
 934                 if (sdata->u.ibss.ie)
 935                         sdata->u.ibss.ie_len = params->ie_len;
 936         }
 937
 938         sdata->u.ibss.skb = skb;
 939         sdata->u.ibss.state = IEEE80211_IBSS_MLME_SEARCH;
 940         sdata->u.ibss.ibss_join_req = jiffies;
 941
 942         memcpy(sdata->u.ibss.ssid, params->ssid, IEEE80211_MAX_SSID_LEN);
 943         sdata->u.ibss.ssid_len = params->ssid_len;
 944
 945         mutex_unlock(&sdata->u.ibss.mtx);
 946
 947         mutex_lock(&sdata->local->mtx);
 948         ieee80211_recalc_idle(sdata->local);
 949         mutex_unlock(&sdata->local->mtx);
 950
 951         ieee80211_queue_work(&sdata->local->hw, &sdata->work);
 952
 953         return 0;
 954 }
 955
 956 int ieee80211_ibss_leave(struct ieee80211_sub_if_data *sdata)
 957 {
 958         struct sk_buff *skb;
 959         struct ieee80211_if_ibss *ifibss = &sdata->u.ibss;
 960         struct ieee80211_local *local = sdata->local;
 961         struct cfg80211_bss *cbss;
 962         u16 capability;
 963         int active_ibss;
 964
 965         mutex_lock(&sdata->u.ibss.mtx);
 966
 967         active_ibss = ieee80211_sta_active_ibss(sdata);
 968
 969         if (!active_ibss && !is_zero_ether_addr(ifibss->bssid)) {
 970                 capability = WLAN_CAPABILITY_IBSS;
 971
 972                 if (ifibss->privacy)
 973                         capability |= WLAN_CAPABILITY_PRIVACY;
 974
 975                 cbss = cfg80211_get_bss(local->hw.wiphy, ifibss->channel,
 976                                         ifibss->bssid, ifibss->ssid,
 977                                         ifibss->ssid_len, WLAN_CAPABILITY_IBSS |
 978                                         WLAN_CAPABILITY_PRIVACY,
 979                                         capability);
 980
 981                 if (cbss) {
 982                         cfg80211_unlink_bss(local->hw.wiphy, cbss);
 983                         cfg80211_put_bss(cbss);
 984                 }
 985         }
 986
 987         sta_info_flush(sdata->local, sdata);
 988
 989         /* remove beacon */
 990         kfree(sdata->u.ibss.ie);
 991         skb = sdata->u.ibss.presp;
 992         rcu_assign_pointer(sdata->u.ibss.presp, NULL);
 993         sdata->vif.bss_conf.ibss_joined = false;
 994         ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON_ENABLED |
 995                                                 BSS_CHANGED_IBSS);
 996         synchronize_rcu();
 997         kfree_skb(skb);
 998
 999         skb_queue_purge(&sdata->skb_queue);
1000         memset(sdata->u.ibss.bssid, 0, ETH_ALEN);
1001         sdata->u.ibss.ssid_len = 0;
1002
1003         del_timer_sync(&sdata->u.ibss.timer);
1004
1005         mutex_unlock(&sdata->u.ibss.mtx);
1006
1007         mutex_lock(&local->mtx);
1008         ieee80211_recalc_idle(sdata->local);
1009         mutex_unlock(&local->mtx);
1010
1011         return 0;
1012 }