net/mac80211/util.c

   1 /*
   2  * Copyright 2002-2005, Instant802 Networks, Inc.
   3  * Copyright 2005-2006, Devicescape Software, Inc.
   4  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
   5  * Copyright 2007       Johannes Berg <johannes@sipsolutions.net>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * utilities for mac80211
  12  */
  13
  14 #include <net/mac80211.h>
  15 #include <linux/netdevice.h>
  16 #include <linux/types.h>
  17 #include <linux/slab.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/etherdevice.h>
  20 #include <linux/if_arp.h>
  21 #include <linux/wireless.h>
  22 #include <linux/bitmap.h>
  23 #include <net/net_namespace.h>
  24 #include <net/cfg80211.h>
  25 #include <net/rtnetlink.h>
  26
  27 #include "ieee80211_i.h"
  28 #include "rate.h"
  29 #include "mesh.h"
  30 #include "wme.h"
  31
  32 /* privid for wiphys to determine whether they belong to us or not */
  33 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
  34
  35 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
  36 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
  37 const unsigned char rfc1042_header[] __aligned(2) =
  38         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  39
  40 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  41 const unsigned char bridge_tunnel_header[] __aligned(2) =
  42         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  43
  44
  45 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
  46                         enum ieee80211_if_types type)
  47 {
  48         __le16 fc = hdr->frame_control;
  49
  50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
  51         if (len < 16)
  52                 return NULL;
  53
  54         if (ieee80211_is_data(fc)) {
  55                 if (len < 24) /* drop incorrect hdr len (data) */
  56                         return NULL;
  57
  58                 if (ieee80211_has_a4(fc))
  59                         return NULL;
  60                 if (ieee80211_has_tods(fc))
  61                         return hdr->addr1;
  62                 if (ieee80211_has_fromds(fc))
  63                         return hdr->addr2;
  64
  65                 return hdr->addr3;
  66         }
  67
  68         if (ieee80211_is_mgmt(fc)) {
  69                 if (len < 24) /* drop incorrect hdr len (mgmt) */
  70                         return NULL;
  71                 return hdr->addr3;
  72         }
  73
  74         if (ieee80211_is_ctl(fc)) {
  75                 if(ieee80211_is_pspoll(fc))
  76                         return hdr->addr1;
  77
  78                 if (ieee80211_is_back_req(fc)) {
  79                         switch (type) {
  80                         case IEEE80211_IF_TYPE_STA:
  81                                 return hdr->addr2;
  82                         case IEEE80211_IF_TYPE_AP:
  83                         case IEEE80211_IF_TYPE_VLAN:
  84                                 return hdr->addr1;
  85                         default:
  86                                 break; /* fall through to the return */
  87                         }
  88                 }
  89         }
  90
  91         return NULL;
  92 }
  93
  94 unsigned int ieee80211_hdrlen(__le16 fc)
  95 {
  96         unsigned int hdrlen = 24;
  97
  98         if (ieee80211_is_data(fc)) {
  99                 if (ieee80211_has_a4(fc))
 100                         hdrlen = 30;
 101                 if (ieee80211_is_data_qos(fc))
 102                         hdrlen += IEEE80211_QOS_CTL_LEN;
 103                 goto out;
 104         }
 105
 106         if (ieee80211_is_ctl(fc)) {
 107                 /*
 108                  * ACK and CTS are 10 bytes, all others 16. To see how
 109                  * to get this condition consider
 110                  *   subtype mask:   0b0000000011110000 (0x00F0)
 111                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 112                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 113                  *   bits that matter:         ^^^      (0x00E0)
 114                  *   value of those: 0b0000000011000000 (0x00C0)
 115                  */
 116                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
 117                         hdrlen = 10;
 118                 else
 119                         hdrlen = 16;
 120         }
 121 out:
 122         return hdrlen;
 123 }
 124 EXPORT_SYMBOL(ieee80211_hdrlen);
 125
 126 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 127 {
 128         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
 129         unsigned int hdrlen;
 130
 131         if (unlikely(skb->len < 10))
 132                 return 0;
 133         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 134         if (unlikely(hdrlen > skb->len))
 135                 return 0;
 136         return hdrlen;
 137 }
 138 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 139
 140 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 141 {
 142         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
 143         /* 7.1.3.5a.2 */
 144         switch (ae) {
 145         case 0:
 146                 return 6;
 147         case 1:
 148                 return 12;
 149         case 2:
 150                 return 18;
 151         case 3:
 152                 return 24;
 153         default:
 154                 return 6;
 155         }
 156 }
 157
 158 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 159 {
 160         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 161
 162         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 163         if (tx->extra_frag) {
 164                 struct ieee80211_hdr *fhdr;
 165                 int i;
 166                 for (i = 0; i < tx->num_extra_frag; i++) {
 167                         fhdr = (struct ieee80211_hdr *)
 168                                 tx->extra_frag[i]->data;
 169                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 170                 }
 171         }
 172 }
 173
 174 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 175                              int rate, int erp, int short_preamble)
 176 {
 177         int dur;
 178
 179         /* calculate duration (in microseconds, rounded up to next higher
 180          * integer if it includes a fractional microsecond) to send frame of
 181          * len bytes (does not include FCS) at the given rate. Duration will
 182          * also include SIFS.
 183          *
 184          * rate is in 100 kbps, so divident is multiplied by 10 in the
 185          * DIV_ROUND_UP() operations.
 186          */
 187
 188         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
 189                 /*
 190                  * OFDM:
 191                  *
 192                  * N_DBPS = DATARATE x 4
 193                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 194                  *      (16 = SIGNAL time, 6 = tail bits)
 195                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 196                  *
 197                  * T_SYM = 4 usec
 198                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 199                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 200                  *      signal ext = 6 usec
 201                  */
 202                 dur = 16; /* SIFS + signal ext */
 203                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 204                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 205                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 206                                         4 * rate); /* T_SYM x N_SYM */
 207         } else {
 208                 /*
 209                  * 802.11b or 802.11g with 802.11b compatibility:
 210                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 211                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 212                  *
 213                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 214                  * aSIFSTime = 10 usec
 215                  * aPreambleLength = 144 usec or 72 usec with short preamble
 216                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 217                  */
 218                 dur = 10; /* aSIFSTime = 10 usec */
 219                 dur += short_preamble ? (72 + 24) : (144 + 48);
 220
 221                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 222         }
 223
 224         return dur;
 225 }
 226
 227 /* Exported duration function for driver use */
 228 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 229                                         struct ieee80211_vif *vif,
 230                                         size_t frame_len,
 231                                         struct ieee80211_rate *rate)
 232 {
 233         struct ieee80211_local *local = hw_to_local(hw);
 234         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 235         u16 dur;
 236         int erp;
 237
 238         erp = 0;
 239         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 240                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 241
 242         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
 243                                        sdata->bss_conf.use_short_preamble);
 244
 245         return cpu_to_le16(dur);
 246 }
 247 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 248
 249 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 250                               struct ieee80211_vif *vif, size_t frame_len,
 251                               const struct ieee80211_tx_info *frame_txctl)
 252 {
 253         struct ieee80211_local *local = hw_to_local(hw);
 254         struct ieee80211_rate *rate;
 255         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 256         bool short_preamble;
 257         int erp;
 258         u16 dur;
 259         struct ieee80211_supported_band *sband;
 260
 261         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 262
 263         short_preamble = sdata->bss_conf.use_short_preamble;
 264
 265         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 266
 267         erp = 0;
 268         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 269                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 270
 271         /* CTS duration */
 272         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
 273                                        erp, short_preamble);
 274         /* Data frame duration */
 275         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
 276                                         erp, short_preamble);
 277         /* ACK duration */
 278         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 279                                         erp, short_preamble);
 280
 281         return cpu_to_le16(dur);
 282 }
 283 EXPORT_SYMBOL(ieee80211_rts_duration);
 284
 285 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 286                                     struct ieee80211_vif *vif,
 287                                     size_t frame_len,
 288                                     const struct ieee80211_tx_info *frame_txctl)
 289 {
 290         struct ieee80211_local *local = hw_to_local(hw);
 291         struct ieee80211_rate *rate;
 292         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 293         bool short_preamble;
 294         int erp;
 295         u16 dur;
 296         struct ieee80211_supported_band *sband;
 297
 298         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 299
 300         short_preamble = sdata->bss_conf.use_short_preamble;
 301
 302         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 303         erp = 0;
 304         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 305                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 306
 307         /* Data frame duration */
 308         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
 309                                        erp, short_preamble);
 310         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
 311                 /* ACK duration */
 312                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 313                                                 erp, short_preamble);
 314         }
 315
 316         return cpu_to_le16(dur);
 317 }
 318 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 319
 320 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 321 {
 322         struct ieee80211_local *local = hw_to_local(hw);
 323
 324         if (test_bit(queue, local->queues_pending)) {
 325                 set_bit(queue, local->queues_pending_run);
 326                 tasklet_schedule(&local->tx_pending_tasklet);
 327         } else {
 328                 netif_wake_subqueue(local->mdev, queue);
 329         }
 330 }
 331 EXPORT_SYMBOL(ieee80211_wake_queue);
 332
 333 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 334 {
 335         struct ieee80211_local *local = hw_to_local(hw);
 336
 337         netif_stop_subqueue(local->mdev, queue);
 338 }
 339 EXPORT_SYMBOL(ieee80211_stop_queue);
 340
 341 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 342 {
 343         int i;
 344
 345         for (i = 0; i < ieee80211_num_queues(hw); i++)
 346                 ieee80211_stop_queue(hw, i);
 347 }
 348 EXPORT_SYMBOL(ieee80211_stop_queues);
 349
 350 int ieee80211_queue_stopped(struct ieee80211_hw *hw, int queue)
 351 {
 352         struct ieee80211_local *local = hw_to_local(hw);
 353         return __netif_subqueue_stopped(local->mdev, queue);
 354 }
 355 EXPORT_SYMBOL(ieee80211_queue_stopped);
 356
 357 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 358 {
 359         int i;
 360
 361         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
 362                 ieee80211_wake_queue(hw, i);
 363 }
 364 EXPORT_SYMBOL(ieee80211_wake_queues);
 365
 366 void ieee80211_iterate_active_interfaces(
 367         struct ieee80211_hw *hw,
 368         void (*iterator)(void *data, u8 *mac,
 369                          struct ieee80211_vif *vif),
 370         void *data)
 371 {
 372         struct ieee80211_local *local = hw_to_local(hw);
 373         struct ieee80211_sub_if_data *sdata;
 374
 375         rtnl_lock();
 376
 377         list_for_each_entry(sdata, &local->interfaces, list) {
 378                 switch (sdata->vif.type) {
 379                 case IEEE80211_IF_TYPE_INVALID:
 380                 case IEEE80211_IF_TYPE_MNTR:
 381                 case IEEE80211_IF_TYPE_VLAN:
 382                         continue;
 383                 case IEEE80211_IF_TYPE_AP:
 384                 case IEEE80211_IF_TYPE_STA:
 385                 case IEEE80211_IF_TYPE_IBSS:
 386                 case IEEE80211_IF_TYPE_WDS:
 387                 case IEEE80211_IF_TYPE_MESH_POINT:
 388                         break;
 389                 }
 390                 if (netif_running(sdata->dev))
 391                         iterator(data, sdata->dev->dev_addr,
 392                                  &sdata->vif);
 393         }
 394
 395         rtnl_unlock();
 396 }
 397 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
 398
 399 void ieee80211_iterate_active_interfaces_atomic(
 400         struct ieee80211_hw *hw,
 401         void (*iterator)(void *data, u8 *mac,
 402                          struct ieee80211_vif *vif),
 403         void *data)
 404 {
 405         struct ieee80211_local *local = hw_to_local(hw);
 406         struct ieee80211_sub_if_data *sdata;
 407
 408         rcu_read_lock();
 409
 410         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 411                 switch (sdata->vif.type) {
 412                 case IEEE80211_IF_TYPE_INVALID:
 413                 case IEEE80211_IF_TYPE_MNTR:
 414                 case IEEE80211_IF_TYPE_VLAN:
 415                         continue;
 416                 case IEEE80211_IF_TYPE_AP:
 417                 case IEEE80211_IF_TYPE_STA:
 418                 case IEEE80211_IF_TYPE_IBSS:
 419                 case IEEE80211_IF_TYPE_WDS:
 420                 case IEEE80211_IF_TYPE_MESH_POINT:
 421                         break;
 422                 }
 423                 if (netif_running(sdata->dev))
 424                         iterator(data, sdata->dev->dev_addr,
 425                                  &sdata->vif);
 426         }
 427
 428         rcu_read_unlock();
 429 }
 430 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);
 431
 432 void ieee802_11_parse_elems(u8 *start, size_t len,
 433                             struct ieee802_11_elems *elems)
 434 {
 435         size_t left = len;
 436         u8 *pos = start;
 437
 438         memset(elems, 0, sizeof(*elems));
 439         elems->ie_start = start;
 440         elems->total_len = len;
 441
 442         while (left >= 2) {
 443                 u8 id, elen;
 444
 445                 id = *pos++;
 446                 elen = *pos++;
 447                 left -= 2;
 448
 449                 if (elen > left)
 450                         return;
 451
 452                 switch (id) {
 453                 case WLAN_EID_SSID:
 454                         elems->ssid = pos;
 455                         elems->ssid_len = elen;
 456                         break;
 457                 case WLAN_EID_SUPP_RATES:
 458                         elems->supp_rates = pos;
 459                         elems->supp_rates_len = elen;
 460                         break;
 461                 case WLAN_EID_FH_PARAMS:
 462                         elems->fh_params = pos;
 463                         elems->fh_params_len = elen;
 464                         break;
 465                 case WLAN_EID_DS_PARAMS:
 466                         elems->ds_params = pos;
 467                         elems->ds_params_len = elen;
 468                         break;
 469                 case WLAN_EID_CF_PARAMS:
 470                         elems->cf_params = pos;
 471                         elems->cf_params_len = elen;
 472                         break;
 473                 case WLAN_EID_TIM:
 474                         elems->tim = pos;
 475                         elems->tim_len = elen;
 476                         break;
 477                 case WLAN_EID_IBSS_PARAMS:
 478                         elems->ibss_params = pos;
 479                         elems->ibss_params_len = elen;
 480                         break;
 481                 case WLAN_EID_CHALLENGE:
 482                         elems->challenge = pos;
 483                         elems->challenge_len = elen;
 484                         break;
 485                 case WLAN_EID_WPA:
 486                         if (elen >= 4 && pos[0] == 0x00 && pos[1] == 0x50 &&
 487                             pos[2] == 0xf2) {
 488                                 /* Microsoft OUI (00:50:F2) */
 489                                 if (pos[3] == 1) {
 490                                         /* OUI Type 1 - WPA IE */
 491                                         elems->wpa = pos;
 492                                         elems->wpa_len = elen;
 493                                 } else if (elen >= 5 && pos[3] == 2) {
 494                                         if (pos[4] == 0) {
 495                                                 elems->wmm_info = pos;
 496                                                 elems->wmm_info_len = elen;
 497                                         } else if (pos[4] == 1) {
 498                                                 elems->wmm_param = pos;
 499                                                 elems->wmm_param_len = elen;
 500                                         }
 501                                 }
 502                         }
 503                         break;
 504                 case WLAN_EID_RSN:
 505                         elems->rsn = pos;
 506                         elems->rsn_len = elen;
 507                         break;
 508                 case WLAN_EID_ERP_INFO:
 509                         elems->erp_info = pos;
 510                         elems->erp_info_len = elen;
 511                         break;
 512                 case WLAN_EID_EXT_SUPP_RATES:
 513                         elems->ext_supp_rates = pos;
 514                         elems->ext_supp_rates_len = elen;
 515                         break;
 516                 case WLAN_EID_HT_CAPABILITY:
 517                         elems->ht_cap_elem = pos;
 518                         elems->ht_cap_elem_len = elen;
 519                         break;
 520                 case WLAN_EID_HT_EXTRA_INFO:
 521                         elems->ht_info_elem = pos;
 522                         elems->ht_info_elem_len = elen;
 523                         break;
 524                 case WLAN_EID_MESH_ID:
 525                         elems->mesh_id = pos;
 526                         elems->mesh_id_len = elen;
 527                         break;
 528                 case WLAN_EID_MESH_CONFIG:
 529                         elems->mesh_config = pos;
 530                         elems->mesh_config_len = elen;
 531                         break;
 532                 case WLAN_EID_PEER_LINK:
 533                         elems->peer_link = pos;
 534                         elems->peer_link_len = elen;
 535                         break;
 536                 case WLAN_EID_PREQ:
 537                         elems->preq = pos;
 538                         elems->preq_len = elen;
 539                         break;
 540                 case WLAN_EID_PREP:
 541                         elems->prep = pos;
 542                         elems->prep_len = elen;
 543                         break;
 544                 case WLAN_EID_PERR:
 545                         elems->perr = pos;
 546                         elems->perr_len = elen;
 547                         break;
 548                 case WLAN_EID_CHANNEL_SWITCH:
 549                         elems->ch_switch_elem = pos;
 550                         elems->ch_switch_elem_len = elen;
 551                         break;
 552                 case WLAN_EID_QUIET:
 553                         if (!elems->quiet_elem) {
 554                                 elems->quiet_elem = pos;
 555                                 elems->quiet_elem_len = elen;
 556                         }
 557                         elems->num_of_quiet_elem++;
 558                         break;
 559                 case WLAN_EID_COUNTRY:
 560                         elems->country_elem = pos;
 561                         elems->country_elem_len = elen;
 562                         break;
 563                 case WLAN_EID_PWR_CONSTRAINT:
 564                         elems->pwr_constr_elem = pos;
 565                         elems->pwr_constr_elem_len = elen;
 566                         break;
 567                 default:
 568                         break;
 569                 }
 570
 571                 left -= elen;
 572                 pos += elen;
 573         }
 574 }