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 int ieee80211_get_hdrlen(u16 fc)
  95 {
  96         int hdrlen = 24;
  97
  98         switch (fc & IEEE80211_FCTL_FTYPE) {
  99         case IEEE80211_FTYPE_DATA:
 100                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 101                         hdrlen = 30; /* Addr4 */
 102                 /*
 103                  * The QoS Control field is two bytes and its presence is
 104                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 105                  * hdrlen if that bit is set.
 106                  * This works by masking out the bit and shifting it to
 107                  * bit position 1 so the result has the value 0 or 2.
 108                  */
 109                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 110                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 111                 break;
 112         case IEEE80211_FTYPE_CTL:
 113                 /*
 114                  * ACK and CTS are 10 bytes, all others 16. To see how
 115                  * to get this condition consider
 116                  *   subtype mask:   0b0000000011110000 (0x00F0)
 117                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 118                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 119                  *   bits that matter:         ^^^      (0x00E0)
 120                  *   value of those: 0b0000000011000000 (0x00C0)
 121                  */
 122                 if ((fc & 0xE0) == 0xC0)
 123                         hdrlen = 10;
 124                 else
 125                         hdrlen = 16;
 126                 break;
 127         }
 128
 129         return hdrlen;
 130 }
 131 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 132
 133 unsigned int ieee80211_hdrlen(__le16 fc)
 134 {
 135         unsigned int hdrlen = 24;
 136
 137         if (ieee80211_is_data(fc)) {
 138                 if (ieee80211_has_a4(fc))
 139                         hdrlen = 30;
 140                 if (ieee80211_is_data_qos(fc))
 141                         hdrlen += IEEE80211_QOS_CTL_LEN;
 142                 goto out;
 143         }
 144
 145         if (ieee80211_is_ctl(fc)) {
 146                 /*
 147                  * ACK and CTS are 10 bytes, all others 16. To see how
 148                  * to get this condition consider
 149                  *   subtype mask:   0b0000000011110000 (0x00F0)
 150                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 151                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 152                  *   bits that matter:         ^^^      (0x00E0)
 153                  *   value of those: 0b0000000011000000 (0x00C0)
 154                  */
 155                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
 156                         hdrlen = 10;
 157                 else
 158                         hdrlen = 16;
 159         }
 160 out:
 161         return hdrlen;
 162 }
 163 EXPORT_SYMBOL(ieee80211_hdrlen);
 164
 165 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 166 {
 167         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
 168         unsigned int hdrlen;
 169
 170         if (unlikely(skb->len < 10))
 171                 return 0;
 172         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 173         if (unlikely(hdrlen > skb->len))
 174                 return 0;
 175         return hdrlen;
 176 }
 177 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 178
 179 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 180 {
 181         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
 182         /* 7.1.3.5a.2 */
 183         switch (ae) {
 184         case 0:
 185                 return 6;
 186         case 1:
 187                 return 12;
 188         case 2:
 189                 return 18;
 190         case 3:
 191                 return 24;
 192         default:
 193                 return 6;
 194         }
 195 }
 196
 197 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 198 {
 199         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 200
 201         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 202         if (tx->extra_frag) {
 203                 struct ieee80211_hdr *fhdr;
 204                 int i;
 205                 for (i = 0; i < tx->num_extra_frag; i++) {
 206                         fhdr = (struct ieee80211_hdr *)
 207                                 tx->extra_frag[i]->data;
 208                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 209                 }
 210         }
 211 }
 212
 213 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 214                              int rate, int erp, int short_preamble)
 215 {
 216         int dur;
 217
 218         /* calculate duration (in microseconds, rounded up to next higher
 219          * integer if it includes a fractional microsecond) to send frame of
 220          * len bytes (does not include FCS) at the given rate. Duration will
 221          * also include SIFS.
 222          *
 223          * rate is in 100 kbps, so divident is multiplied by 10 in the
 224          * DIV_ROUND_UP() operations.
 225          */
 226
 227         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
 228                 /*
 229                  * OFDM:
 230                  *
 231                  * N_DBPS = DATARATE x 4
 232                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 233                  *      (16 = SIGNAL time, 6 = tail bits)
 234                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 235                  *
 236                  * T_SYM = 4 usec
 237                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 238                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 239                  *      signal ext = 6 usec
 240                  */
 241                 dur = 16; /* SIFS + signal ext */
 242                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 243                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 244                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 245                                         4 * rate); /* T_SYM x N_SYM */
 246         } else {
 247                 /*
 248                  * 802.11b or 802.11g with 802.11b compatibility:
 249                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 250                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 251                  *
 252                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 253                  * aSIFSTime = 10 usec
 254                  * aPreambleLength = 144 usec or 72 usec with short preamble
 255                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 256                  */
 257                 dur = 10; /* aSIFSTime = 10 usec */
 258                 dur += short_preamble ? (72 + 24) : (144 + 48);
 259
 260                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 261         }
 262
 263         return dur;
 264 }
 265
 266 /* Exported duration function for driver use */
 267 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 268                                         struct ieee80211_vif *vif,
 269                                         size_t frame_len,
 270                                         struct ieee80211_rate *rate)
 271 {
 272         struct ieee80211_local *local = hw_to_local(hw);
 273         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 274         u16 dur;
 275         int erp;
 276
 277         erp = 0;
 278         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 279                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 280
 281         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
 282                                        sdata->bss_conf.use_short_preamble);
 283
 284         return cpu_to_le16(dur);
 285 }
 286 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 287
 288 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 289                               struct ieee80211_vif *vif, size_t frame_len,
 290                               const struct ieee80211_tx_info *frame_txctl)
 291 {
 292         struct ieee80211_local *local = hw_to_local(hw);
 293         struct ieee80211_rate *rate;
 294         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 295         bool short_preamble;
 296         int erp;
 297         u16 dur;
 298         struct ieee80211_supported_band *sband;
 299
 300         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 301
 302         short_preamble = sdata->bss_conf.use_short_preamble;
 303
 304         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 305
 306         erp = 0;
 307         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 308                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 309
 310         /* CTS duration */
 311         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
 312                                        erp, short_preamble);
 313         /* Data frame duration */
 314         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
 315                                         erp, short_preamble);
 316         /* ACK duration */
 317         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 318                                         erp, short_preamble);
 319
 320         return cpu_to_le16(dur);
 321 }
 322 EXPORT_SYMBOL(ieee80211_rts_duration);
 323
 324 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 325                                     struct ieee80211_vif *vif,
 326                                     size_t frame_len,
 327                                     const struct ieee80211_tx_info *frame_txctl)
 328 {
 329         struct ieee80211_local *local = hw_to_local(hw);
 330         struct ieee80211_rate *rate;
 331         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 332         bool short_preamble;
 333         int erp;
 334         u16 dur;
 335         struct ieee80211_supported_band *sband;
 336
 337         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 338
 339         short_preamble = sdata->bss_conf.use_short_preamble;
 340
 341         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 342         erp = 0;
 343         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 344                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 345
 346         /* Data frame duration */
 347         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
 348                                        erp, short_preamble);
 349         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
 350                 /* ACK duration */
 351                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 352                                                 erp, short_preamble);
 353         }
 354
 355         return cpu_to_le16(dur);
 356 }
 357 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 358
 359 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 360 {
 361         struct ieee80211_local *local = hw_to_local(hw);
 362
 363         if (test_bit(queue, local->queues_pending)) {
 364                 tasklet_schedule(&local->tx_pending_tasklet);
 365         } else {
 366                 netif_wake_subqueue(local->mdev, queue);
 367         }
 368 }
 369 EXPORT_SYMBOL(ieee80211_wake_queue);
 370
 371 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 372 {
 373         struct ieee80211_local *local = hw_to_local(hw);
 374
 375         netif_stop_subqueue(local->mdev, queue);
 376 }
 377 EXPORT_SYMBOL(ieee80211_stop_queue);
 378
 379 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 380 {
 381         int i;
 382
 383         for (i = 0; i < ieee80211_num_queues(hw); i++)
 384                 ieee80211_stop_queue(hw, i);
 385 }
 386 EXPORT_SYMBOL(ieee80211_stop_queues);
 387
 388 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 389 {
 390         int i;
 391
 392         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
 393                 ieee80211_wake_queue(hw, i);
 394 }
 395 EXPORT_SYMBOL(ieee80211_wake_queues);
 396
 397 void ieee80211_iterate_active_interfaces(
 398         struct ieee80211_hw *hw,
 399         void (*iterator)(void *data, u8 *mac,
 400                          struct ieee80211_vif *vif),
 401         void *data)
 402 {
 403         struct ieee80211_local *local = hw_to_local(hw);
 404         struct ieee80211_sub_if_data *sdata;
 405
 406         rtnl_lock();
 407
 408         list_for_each_entry(sdata, &local->interfaces, list) {
 409                 switch (sdata->vif.type) {
 410                 case IEEE80211_IF_TYPE_INVALID:
 411                 case IEEE80211_IF_TYPE_MNTR:
 412                 case IEEE80211_IF_TYPE_VLAN:
 413                         continue;
 414                 case IEEE80211_IF_TYPE_AP:
 415                 case IEEE80211_IF_TYPE_STA:
 416                 case IEEE80211_IF_TYPE_IBSS:
 417                 case IEEE80211_IF_TYPE_WDS:
 418                 case IEEE80211_IF_TYPE_MESH_POINT:
 419                         break;
 420                 }
 421                 if (netif_running(sdata->dev))
 422                         iterator(data, sdata->dev->dev_addr,
 423                                  &sdata->vif);
 424         }
 425
 426         rtnl_unlock();
 427 }
 428 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
 429
 430 void ieee80211_iterate_active_interfaces_atomic(
 431         struct ieee80211_hw *hw,
 432         void (*iterator)(void *data, u8 *mac,
 433                          struct ieee80211_vif *vif),
 434         void *data)
 435 {
 436         struct ieee80211_local *local = hw_to_local(hw);
 437         struct ieee80211_sub_if_data *sdata;
 438
 439         rcu_read_lock();
 440
 441         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 442                 switch (sdata->vif.type) {
 443                 case IEEE80211_IF_TYPE_INVALID:
 444                 case IEEE80211_IF_TYPE_MNTR:
 445                 case IEEE80211_IF_TYPE_VLAN:
 446                         continue;
 447                 case IEEE80211_IF_TYPE_AP:
 448                 case IEEE80211_IF_TYPE_STA:
 449                 case IEEE80211_IF_TYPE_IBSS:
 450                 case IEEE80211_IF_TYPE_WDS:
 451                 case IEEE80211_IF_TYPE_MESH_POINT:
 452                         break;
 453                 }
 454                 if (netif_running(sdata->dev))
 455                         iterator(data, sdata->dev->dev_addr,
 456                                  &sdata->vif);
 457         }
 458
 459         rcu_read_unlock();
 460 }
 461 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);