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 "ieee80211_rate.h"
  29 #include "wme.h"
  30
  31 /* privid for wiphys to determine whether they belong to us or not */
  32 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
  33
  34 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
  35 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
  36 const unsigned char rfc1042_header[] =
  37         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  38
  39 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  40 const unsigned char bridge_tunnel_header[] =
  41         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  42
  43
  44 static int rate_list_match(const int *rate_list, int rate)
  45 {
  46         int i;
  47
  48         if (!rate_list)
  49                 return 0;
  50
  51         for (i = 0; rate_list[i] >= 0; i++)
  52                 if (rate_list[i] == rate)
  53                         return 1;
  54
  55         return 0;
  56 }
  57
  58 void ieee80211_prepare_rates(struct ieee80211_local *local,
  59                              struct ieee80211_hw_mode *mode)
  60 {
  61         int i;
  62
  63         for (i = 0; i < mode->num_rates; i++) {
  64                 struct ieee80211_rate *rate = &mode->rates[i];
  65
  66                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
  67                                  IEEE80211_RATE_BASIC);
  68
  69                 if (local->supp_rates[mode->mode]) {
  70                         if (!rate_list_match(local->supp_rates[mode->mode],
  71                                              rate->rate))
  72                                 continue;
  73                 }
  74
  75                 rate->flags |= IEEE80211_RATE_SUPPORTED;
  76
  77                 /* Use configured basic rate set if it is available. If not,
  78                  * use defaults that are sane for most cases. */
  79                 if (local->basic_rates[mode->mode]) {
  80                         if (rate_list_match(local->basic_rates[mode->mode],
  81                                             rate->rate))
  82                                 rate->flags |= IEEE80211_RATE_BASIC;
  83                 } else switch (mode->mode) {
  84                 case MODE_IEEE80211A:
  85                         if (rate->rate == 60 || rate->rate == 120 ||
  86                             rate->rate == 240)
  87                                 rate->flags |= IEEE80211_RATE_BASIC;
  88                         break;
  89                 case MODE_IEEE80211B:
  90                         if (rate->rate == 10 || rate->rate == 20)
  91                                 rate->flags |= IEEE80211_RATE_BASIC;
  92                         break;
  93                 case MODE_IEEE80211G:
  94                         if (rate->rate == 10 || rate->rate == 20 ||
  95                             rate->rate == 55 || rate->rate == 110)
  96                                 rate->flags |= IEEE80211_RATE_BASIC;
  97                         break;
  98                 case NUM_IEEE80211_MODES:
  99                         /* not useful */
 100                         break;
 101                 }
 102
 103                 /* Set ERP and MANDATORY flags based on phymode */
 104                 switch (mode->mode) {
 105                 case MODE_IEEE80211A:
 106                         if (rate->rate == 60 || rate->rate == 120 ||
 107                             rate->rate == 240)
 108                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 109                         break;
 110                 case MODE_IEEE80211B:
 111                         if (rate->rate == 10)
 112                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 113                         break;
 114                 case MODE_IEEE80211G:
 115                         if (rate->rate == 10 || rate->rate == 20 ||
 116                             rate->rate == 55 || rate->rate == 110 ||
 117                             rate->rate == 60 || rate->rate == 120 ||
 118                             rate->rate == 240)
 119                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 120                         break;
 121                 case NUM_IEEE80211_MODES:
 122                         /* not useful */
 123                         break;
 124                 }
 125                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 126                         rate->flags |= IEEE80211_RATE_ERP;
 127         }
 128 }
 129
 130 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
 131                         enum ieee80211_if_types type)
 132 {
 133         u16 fc;
 134
 135          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
 136         if (len < 16)
 137                 return NULL;
 138
 139         fc = le16_to_cpu(hdr->frame_control);
 140
 141         switch (fc & IEEE80211_FCTL_FTYPE) {
 142         case IEEE80211_FTYPE_DATA:
 143                 if (len < 24) /* drop incorrect hdr len (data) */
 144                         return NULL;
 145                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 146                 case IEEE80211_FCTL_TODS:
 147                         return hdr->addr1;
 148                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
 149                         return NULL;
 150                 case IEEE80211_FCTL_FROMDS:
 151                         return hdr->addr2;
 152                 case 0:
 153                         return hdr->addr3;
 154                 }
 155                 break;
 156         case IEEE80211_FTYPE_MGMT:
 157                 if (len < 24) /* drop incorrect hdr len (mgmt) */
 158                         return NULL;
 159                 return hdr->addr3;
 160         case IEEE80211_FTYPE_CTL:
 161                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 162                         return hdr->addr1;
 163                 else if ((fc & IEEE80211_FCTL_STYPE) ==
 164                                                 IEEE80211_STYPE_BACK_REQ) {
 165                         switch (type) {
 166                         case IEEE80211_IF_TYPE_STA:
 167                                 return hdr->addr2;
 168                         case IEEE80211_IF_TYPE_AP:
 169                         case IEEE80211_IF_TYPE_VLAN:
 170                                 return hdr->addr1;
 171                         default:
 172                                 return NULL;
 173                         }
 174                 }
 175                 else
 176                         return NULL;
 177         }
 178
 179         return NULL;
 180 }
 181
 182 int ieee80211_get_hdrlen(u16 fc)
 183 {
 184         int hdrlen = 24;
 185
 186         switch (fc & IEEE80211_FCTL_FTYPE) {
 187         case IEEE80211_FTYPE_DATA:
 188                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 189                         hdrlen = 30; /* Addr4 */
 190                 /*
 191                  * The QoS Control field is two bytes and its presence is
 192                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 193                  * hdrlen if that bit is set.
 194                  * This works by masking out the bit and shifting it to
 195                  * bit position 1 so the result has the value 0 or 2.
 196                  */
 197                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 198                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 199                 break;
 200         case IEEE80211_FTYPE_CTL:
 201                 /*
 202                  * ACK and CTS are 10 bytes, all others 16. To see how
 203                  * to get this condition consider
 204                  *   subtype mask:   0b0000000011110000 (0x00F0)
 205                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 206                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 207                  *   bits that matter:         ^^^      (0x00E0)
 208                  *   value of those: 0b0000000011000000 (0x00C0)
 209                  */
 210                 if ((fc & 0xE0) == 0xC0)
 211                         hdrlen = 10;
 212                 else
 213                         hdrlen = 16;
 214                 break;
 215         }
 216
 217         return hdrlen;
 218 }
 219 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 220
 221 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 222 {
 223         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 224         int hdrlen;
 225
 226         if (unlikely(skb->len < 10))
 227                 return 0;
 228         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 229         if (unlikely(hdrlen > skb->len))
 230                 return 0;
 231         return hdrlen;
 232 }
 233 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 234
 235 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 236 {
 237         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 238
 239         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 240         if (tx->u.tx.extra_frag) {
 241                 struct ieee80211_hdr *fhdr;
 242                 int i;
 243                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 244                         fhdr = (struct ieee80211_hdr *)
 245                                 tx->u.tx.extra_frag[i]->data;
 246                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 247                 }
 248         }
 249 }
 250
 251 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 252                              int rate, int erp, int short_preamble)
 253 {
 254         int dur;
 255
 256         /* calculate duration (in microseconds, rounded up to next higher
 257          * integer if it includes a fractional microsecond) to send frame of
 258          * len bytes (does not include FCS) at the given rate. Duration will
 259          * also include SIFS.
 260          *
 261          * rate is in 100 kbps, so divident is multiplied by 10 in the
 262          * DIV_ROUND_UP() operations.
 263          */
 264
 265         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 266                 /*
 267                  * OFDM:
 268                  *
 269                  * N_DBPS = DATARATE x 4
 270                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 271                  *      (16 = SIGNAL time, 6 = tail bits)
 272                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 273                  *
 274                  * T_SYM = 4 usec
 275                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 276                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 277                  *      signal ext = 6 usec
 278                  */
 279                 dur = 16; /* SIFS + signal ext */
 280                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 281                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 282                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 283                                         4 * rate); /* T_SYM x N_SYM */
 284         } else {
 285                 /*
 286                  * 802.11b or 802.11g with 802.11b compatibility:
 287                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 288                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 289                  *
 290                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 291                  * aSIFSTime = 10 usec
 292                  * aPreambleLength = 144 usec or 72 usec with short preamble
 293                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 294                  */
 295                 dur = 10; /* aSIFSTime = 10 usec */
 296                 dur += short_preamble ? (72 + 24) : (144 + 48);
 297
 298                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 299         }
 300
 301         return dur;
 302 }
 303
 304 /* Exported duration function for driver use */
 305 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 306                                         struct ieee80211_vif *vif,
 307                                         size_t frame_len, int rate)
 308 {
 309         struct ieee80211_local *local = hw_to_local(hw);
 310         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 311         u16 dur;
 312         int erp;
 313
 314         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 315         dur = ieee80211_frame_duration(local, frame_len, rate, erp,
 316                                        sdata->bss_conf.use_short_preamble);
 317
 318         return cpu_to_le16(dur);
 319 }
 320 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 321
 322 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 323                               struct ieee80211_vif *vif, size_t frame_len,
 324                               const struct ieee80211_tx_control *frame_txctl)
 325 {
 326         struct ieee80211_local *local = hw_to_local(hw);
 327         struct ieee80211_rate *rate;
 328         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 329         bool short_preamble;
 330         int erp;
 331         u16 dur;
 332
 333         short_preamble = sdata->bss_conf.use_short_preamble;
 334
 335         rate = frame_txctl->rts_rate;
 336         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 337
 338         /* CTS duration */
 339         dur = ieee80211_frame_duration(local, 10, rate->rate,
 340                                        erp, short_preamble);
 341         /* Data frame duration */
 342         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 343                                         erp, short_preamble);
 344         /* ACK duration */
 345         dur += ieee80211_frame_duration(local, 10, rate->rate,
 346                                         erp, short_preamble);
 347
 348         return cpu_to_le16(dur);
 349 }
 350 EXPORT_SYMBOL(ieee80211_rts_duration);
 351
 352 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 353                                     struct ieee80211_vif *vif,
 354                                     size_t frame_len,
 355                                     const struct ieee80211_tx_control *frame_txctl)
 356 {
 357         struct ieee80211_local *local = hw_to_local(hw);
 358         struct ieee80211_rate *rate;
 359         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 360         bool short_preamble;
 361         int erp;
 362         u16 dur;
 363
 364         short_preamble = sdata->bss_conf.use_short_preamble;
 365
 366         rate = frame_txctl->rts_rate;
 367         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 368
 369         /* Data frame duration */
 370         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 371                                        erp, short_preamble);
 372         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 373                 /* ACK duration */
 374                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 375                                                 erp, short_preamble);
 376         }
 377
 378         return cpu_to_le16(dur);
 379 }
 380 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 381
 382 struct ieee80211_rate *
 383 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 384 {
 385         struct ieee80211_hw_mode *mode;
 386         int r;
 387
 388         list_for_each_entry(mode, &local->modes_list, list) {
 389                 if (mode->mode != phymode)
 390                         continue;
 391                 for (r = 0; r < mode->num_rates; r++) {
 392                         struct ieee80211_rate *rate = &mode->rates[r];
 393                         if (rate->val == hw_rate ||
 394                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 395                              rate->val2 == hw_rate))
 396                                 return rate;
 397                 }
 398         }
 399
 400         return NULL;
 401 }
 402
 403 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 404 {
 405         struct ieee80211_local *local = hw_to_local(hw);
 406
 407         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 408                                &local->state[queue])) {
 409                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 410                              &local->state[queue]))
 411                         tasklet_schedule(&local->tx_pending_tasklet);
 412                 else
 413                         if (!ieee80211_qdisc_installed(local->mdev)) {
 414                                 if (queue == 0)
 415                                         netif_wake_queue(local->mdev);
 416                         } else
 417                                 __netif_schedule(local->mdev);
 418         }
 419 }
 420 EXPORT_SYMBOL(ieee80211_wake_queue);
 421
 422 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 423 {
 424         struct ieee80211_local *local = hw_to_local(hw);
 425
 426         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 427                 netif_stop_queue(local->mdev);
 428         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 429 }
 430 EXPORT_SYMBOL(ieee80211_stop_queue);
 431
 432 void ieee80211_start_queues(struct ieee80211_hw *hw)
 433 {
 434         struct ieee80211_local *local = hw_to_local(hw);
 435         int i;
 436
 437         for (i = 0; i < local->hw.queues; i++)
 438                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 439         if (!ieee80211_qdisc_installed(local->mdev))
 440                 netif_start_queue(local->mdev);
 441 }
 442 EXPORT_SYMBOL(ieee80211_start_queues);
 443
 444 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 445 {
 446         int i;
 447
 448         for (i = 0; i < hw->queues; i++)
 449                 ieee80211_stop_queue(hw, i);
 450 }
 451 EXPORT_SYMBOL(ieee80211_stop_queues);
 452
 453 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 454 {
 455         int i;
 456
 457         for (i = 0; i < hw->queues; i++)
 458                 ieee80211_wake_queue(hw, i);
 459 }
 460 EXPORT_SYMBOL(ieee80211_wake_queues);
 461
 462 void ieee80211_iterate_active_interfaces(
 463         struct ieee80211_hw *hw,
 464         void (*iterator)(void *data, u8 *mac,
 465                          struct ieee80211_vif *vif),
 466         void *data)
 467 {
 468         struct ieee80211_local *local = hw_to_local(hw);
 469         struct ieee80211_sub_if_data *sdata;
 470
 471         rcu_read_lock();
 472
 473         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 474                 switch (sdata->vif.type) {
 475                 case IEEE80211_IF_TYPE_INVALID:
 476                 case IEEE80211_IF_TYPE_MNTR:
 477                 case IEEE80211_IF_TYPE_VLAN:
 478                         continue;
 479                 case IEEE80211_IF_TYPE_AP:
 480                 case IEEE80211_IF_TYPE_STA:
 481                 case IEEE80211_IF_TYPE_IBSS:
 482                 case IEEE80211_IF_TYPE_WDS:
 483                         break;
 484                 }
 485                 if (sdata->dev == local->mdev)
 486                         continue;
 487                 if (netif_running(sdata->dev))
 488                         iterator(data, sdata->dev->dev_addr,
 489                                  &sdata->vif);
 490         }
 491
 492         rcu_read_unlock();
 493 }
 494 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);