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         u16 fc;
  49
  50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
  51         if (len < 16)
  52                 return NULL;
  53
  54         fc = le16_to_cpu(hdr->frame_control);
  55
  56         switch (fc & IEEE80211_FCTL_FTYPE) {
  57         case IEEE80211_FTYPE_DATA:
  58                 if (len < 24) /* drop incorrect hdr len (data) */
  59                         return NULL;
  60                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
  61                 case IEEE80211_FCTL_TODS:
  62                         return hdr->addr1;
  63                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
  64                         return NULL;
  65                 case IEEE80211_FCTL_FROMDS:
  66                         return hdr->addr2;
  67                 case 0:
  68                         return hdr->addr3;
  69                 }
  70                 break;
  71         case IEEE80211_FTYPE_MGMT:
  72                 if (len < 24) /* drop incorrect hdr len (mgmt) */
  73                         return NULL;
  74                 return hdr->addr3;
  75         case IEEE80211_FTYPE_CTL:
  76                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
  77                         return hdr->addr1;
  78                 else if ((fc & IEEE80211_FCTL_STYPE) ==
  79                                                 IEEE80211_STYPE_BACK_REQ) {
  80                         switch (type) {
  81                         case IEEE80211_IF_TYPE_STA:
  82                                 return hdr->addr2;
  83                         case IEEE80211_IF_TYPE_AP:
  84                         case IEEE80211_IF_TYPE_VLAN:
  85                                 return hdr->addr1;
  86                         default:
  87                                 return NULL;
  88                         }
  89                 }
  90                 else
  91                         return NULL;
  92         }
  93
  94         return NULL;
  95 }
  96
  97 int ieee80211_get_hdrlen(u16 fc)
  98 {
  99         int hdrlen = 24;
 100
 101         switch (fc & IEEE80211_FCTL_FTYPE) {
 102         case IEEE80211_FTYPE_DATA:
 103                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 104                         hdrlen = 30; /* Addr4 */
 105                 /*
 106                  * The QoS Control field is two bytes and its presence is
 107                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 108                  * hdrlen if that bit is set.
 109                  * This works by masking out the bit and shifting it to
 110                  * bit position 1 so the result has the value 0 or 2.
 111                  */
 112                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 113                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 114                 break;
 115         case IEEE80211_FTYPE_CTL:
 116                 /*
 117                  * ACK and CTS are 10 bytes, all others 16. To see how
 118                  * to get this condition consider
 119                  *   subtype mask:   0b0000000011110000 (0x00F0)
 120                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 121                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 122                  *   bits that matter:         ^^^      (0x00E0)
 123                  *   value of those: 0b0000000011000000 (0x00C0)
 124                  */
 125                 if ((fc & 0xE0) == 0xC0)
 126                         hdrlen = 10;
 127                 else
 128                         hdrlen = 16;
 129                 break;
 130         }
 131
 132         return hdrlen;
 133 }
 134 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 135
 136 unsigned int ieee80211_hdrlen(__le16 fc)
 137 {
 138         unsigned int hdrlen = 24;
 139
 140         if (ieee80211_is_data(fc)) {
 141                 if (ieee80211_has_a4(fc))
 142                         hdrlen = 30;
 143                 if (ieee80211_is_data_qos(fc))
 144                         hdrlen += IEEE80211_QOS_CTL_LEN;
 145                 goto out;
 146         }
 147
 148         if (ieee80211_is_ctl(fc)) {
 149                 /*
 150                  * ACK and CTS are 10 bytes, all others 16. To see how
 151                  * to get this condition consider
 152                  *   subtype mask:   0b0000000011110000 (0x00F0)
 153                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 154                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 155                  *   bits that matter:         ^^^      (0x00E0)
 156                  *   value of those: 0b0000000011000000 (0x00C0)
 157                  */
 158                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
 159                         hdrlen = 10;
 160                 else
 161                         hdrlen = 16;
 162         }
 163 out:
 164         return hdrlen;
 165 }
 166 EXPORT_SYMBOL(ieee80211_hdrlen);
 167
 168 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 169 {
 170         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *)skb->data;
 171         unsigned int hdrlen;
 172
 173         if (unlikely(skb->len < 10))
 174                 return 0;
 175         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 176         if (unlikely(hdrlen > skb->len))
 177                 return 0;
 178         return hdrlen;
 179 }
 180 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 181
 182 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 183 {
 184         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
 185         /* 7.1.3.5a.2 */
 186         switch (ae) {
 187         case 0:
 188                 return 6;
 189         case 1:
 190                 return 12;
 191         case 2:
 192                 return 18;
 193         case 3:
 194                 return 24;
 195         default:
 196                 return 6;
 197         }
 198 }
 199
 200 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 201 {
 202         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 203
 204         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 205         if (tx->extra_frag) {
 206                 struct ieee80211_hdr *fhdr;
 207                 int i;
 208                 for (i = 0; i < tx->num_extra_frag; i++) {
 209                         fhdr = (struct ieee80211_hdr *)
 210                                 tx->extra_frag[i]->data;
 211                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 212                 }
 213         }
 214 }
 215
 216 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 217                              int rate, int erp, int short_preamble)
 218 {
 219         int dur;
 220
 221         /* calculate duration (in microseconds, rounded up to next higher
 222          * integer if it includes a fractional microsecond) to send frame of
 223          * len bytes (does not include FCS) at the given rate. Duration will
 224          * also include SIFS.
 225          *
 226          * rate is in 100 kbps, so divident is multiplied by 10 in the
 227          * DIV_ROUND_UP() operations.
 228          */
 229
 230         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
 231                 /*
 232                  * OFDM:
 233                  *
 234                  * N_DBPS = DATARATE x 4
 235                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 236                  *      (16 = SIGNAL time, 6 = tail bits)
 237                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 238                  *
 239                  * T_SYM = 4 usec
 240                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 241                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 242                  *      signal ext = 6 usec
 243                  */
 244                 dur = 16; /* SIFS + signal ext */
 245                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 246                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 247                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 248                                         4 * rate); /* T_SYM x N_SYM */
 249         } else {
 250                 /*
 251                  * 802.11b or 802.11g with 802.11b compatibility:
 252                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 253                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 254                  *
 255                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 256                  * aSIFSTime = 10 usec
 257                  * aPreambleLength = 144 usec or 72 usec with short preamble
 258                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 259                  */
 260                 dur = 10; /* aSIFSTime = 10 usec */
 261                 dur += short_preamble ? (72 + 24) : (144 + 48);
 262
 263                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 264         }
 265
 266         return dur;
 267 }
 268
 269 /* Exported duration function for driver use */
 270 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 271                                         struct ieee80211_vif *vif,
 272                                         size_t frame_len,
 273                                         struct ieee80211_rate *rate)
 274 {
 275         struct ieee80211_local *local = hw_to_local(hw);
 276         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 277         u16 dur;
 278         int erp;
 279
 280         erp = 0;
 281         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 282                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 283
 284         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
 285                                        sdata->bss_conf.use_short_preamble);
 286
 287         return cpu_to_le16(dur);
 288 }
 289 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 290
 291 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 292                               struct ieee80211_vif *vif, size_t frame_len,
 293                               const struct ieee80211_tx_info *frame_txctl)
 294 {
 295         struct ieee80211_local *local = hw_to_local(hw);
 296         struct ieee80211_rate *rate;
 297         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 298         bool short_preamble;
 299         int erp;
 300         u16 dur;
 301         struct ieee80211_supported_band *sband;
 302
 303         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 304
 305         short_preamble = sdata->bss_conf.use_short_preamble;
 306
 307         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 308
 309         erp = 0;
 310         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 311                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 312
 313         /* CTS duration */
 314         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
 315                                        erp, short_preamble);
 316         /* Data frame duration */
 317         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
 318                                         erp, short_preamble);
 319         /* ACK duration */
 320         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 321                                         erp, short_preamble);
 322
 323         return cpu_to_le16(dur);
 324 }
 325 EXPORT_SYMBOL(ieee80211_rts_duration);
 326
 327 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 328                                     struct ieee80211_vif *vif,
 329                                     size_t frame_len,
 330                                     const struct ieee80211_tx_info *frame_txctl)
 331 {
 332         struct ieee80211_local *local = hw_to_local(hw);
 333         struct ieee80211_rate *rate;
 334         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 335         bool short_preamble;
 336         int erp;
 337         u16 dur;
 338         struct ieee80211_supported_band *sband;
 339
 340         sband = local->hw.wiphy->bands[local->hw.conf.channel->band];
 341
 342         short_preamble = sdata->bss_conf.use_short_preamble;
 343
 344         rate = &sband->bitrates[frame_txctl->control.rts_cts_rate_idx];
 345         erp = 0;
 346         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 347                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 348
 349         /* Data frame duration */
 350         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
 351                                        erp, short_preamble);
 352         if (!(frame_txctl->flags & IEEE80211_TX_CTL_NO_ACK)) {
 353                 /* ACK duration */
 354                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 355                                                 erp, short_preamble);
 356         }
 357
 358         return cpu_to_le16(dur);
 359 }
 360 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 361
 362 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 363 {
 364         struct ieee80211_local *local = hw_to_local(hw);
 365
 366         if (test_bit(queue, local->queues_pending)) {
 367                 tasklet_schedule(&local->tx_pending_tasklet);
 368         } else {
 369                 if (ieee80211_is_multiqueue(local)) {
 370                         netif_wake_subqueue(local->mdev, queue);
 371                 } else {
 372                         WARN_ON(queue != 0);
 373                         netif_wake_queue(local->mdev);
 374                 }
 375         }
 376 }
 377 EXPORT_SYMBOL(ieee80211_wake_queue);
 378
 379 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 380 {
 381         struct ieee80211_local *local = hw_to_local(hw);
 382
 383         if (ieee80211_is_multiqueue(local)) {
 384                 netif_stop_subqueue(local->mdev, queue);
 385         } else {
 386                 WARN_ON(queue != 0);
 387                 netif_stop_queue(local->mdev);
 388         }
 389 }
 390 EXPORT_SYMBOL(ieee80211_stop_queue);
 391
 392 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 393 {
 394         int i;
 395
 396         for (i = 0; i < ieee80211_num_queues(hw); i++)
 397                 ieee80211_stop_queue(hw, i);
 398 }
 399 EXPORT_SYMBOL(ieee80211_stop_queues);
 400
 401 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 402 {
 403         int i;
 404
 405         for (i = 0; i < hw->queues + hw->ampdu_queues; i++)
 406                 ieee80211_wake_queue(hw, i);
 407 }
 408 EXPORT_SYMBOL(ieee80211_wake_queues);
 409
 410 void ieee80211_iterate_active_interfaces(
 411         struct ieee80211_hw *hw,
 412         void (*iterator)(void *data, u8 *mac,
 413                          struct ieee80211_vif *vif),
 414         void *data)
 415 {
 416         struct ieee80211_local *local = hw_to_local(hw);
 417         struct ieee80211_sub_if_data *sdata;
 418
 419         rtnl_lock();
 420
 421         list_for_each_entry(sdata, &local->interfaces, list) {
 422                 switch (sdata->vif.type) {
 423                 case IEEE80211_IF_TYPE_INVALID:
 424                 case IEEE80211_IF_TYPE_MNTR:
 425                 case IEEE80211_IF_TYPE_VLAN:
 426                         continue;
 427                 case IEEE80211_IF_TYPE_AP:
 428                 case IEEE80211_IF_TYPE_STA:
 429                 case IEEE80211_IF_TYPE_IBSS:
 430                 case IEEE80211_IF_TYPE_WDS:
 431                 case IEEE80211_IF_TYPE_MESH_POINT:
 432                         break;
 433                 }
 434                 if (sdata->dev == local->mdev)
 435                         continue;
 436                 if (netif_running(sdata->dev))
 437                         iterator(data, sdata->dev->dev_addr,
 438                                  &sdata->vif);
 439         }
 440
 441         rtnl_unlock();
 442 }
 443 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
 444
 445 void ieee80211_iterate_active_interfaces_atomic(
 446         struct ieee80211_hw *hw,
 447         void (*iterator)(void *data, u8 *mac,
 448                          struct ieee80211_vif *vif),
 449         void *data)
 450 {
 451         struct ieee80211_local *local = hw_to_local(hw);
 452         struct ieee80211_sub_if_data *sdata;
 453
 454         rcu_read_lock();
 455
 456         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 457                 switch (sdata->vif.type) {
 458                 case IEEE80211_IF_TYPE_INVALID:
 459                 case IEEE80211_IF_TYPE_MNTR:
 460                 case IEEE80211_IF_TYPE_VLAN:
 461                         continue;
 462                 case IEEE80211_IF_TYPE_AP:
 463                 case IEEE80211_IF_TYPE_STA:
 464                 case IEEE80211_IF_TYPE_IBSS:
 465                 case IEEE80211_IF_TYPE_WDS:
 466                 case IEEE80211_IF_TYPE_MESH_POINT:
 467                         break;
 468                 }
 469                 if (sdata->dev == local->mdev)
 470                         continue;
 471                 if (netif_running(sdata->dev))
 472                         iterator(data, sdata->dev->dev_addr,
 473                                  &sdata->vif);
 474         }
 475
 476         rcu_read_unlock();
 477 }
 478 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces_atomic);