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 /* No encapsulation header if EtherType < 0x600 (=length) */
  44 static const unsigned char eapol_header[] =
  45         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
  46
  47
  48 static int rate_list_match(const int *rate_list, int rate)
  49 {
  50         int i;
  51
  52         if (!rate_list)
  53                 return 0;
  54
  55         for (i = 0; rate_list[i] >= 0; i++)
  56                 if (rate_list[i] == rate)
  57                         return 1;
  58
  59         return 0;
  60 }
  61
  62 void ieee80211_prepare_rates(struct ieee80211_local *local,
  63                              struct ieee80211_hw_mode *mode)
  64 {
  65         int i;
  66
  67         for (i = 0; i < mode->num_rates; i++) {
  68                 struct ieee80211_rate *rate = &mode->rates[i];
  69
  70                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
  71                                  IEEE80211_RATE_BASIC);
  72
  73                 if (local->supp_rates[mode->mode]) {
  74                         if (!rate_list_match(local->supp_rates[mode->mode],
  75                                              rate->rate))
  76                                 continue;
  77                 }
  78
  79                 rate->flags |= IEEE80211_RATE_SUPPORTED;
  80
  81                 /* Use configured basic rate set if it is available. If not,
  82                  * use defaults that are sane for most cases. */
  83                 if (local->basic_rates[mode->mode]) {
  84                         if (rate_list_match(local->basic_rates[mode->mode],
  85                                             rate->rate))
  86                                 rate->flags |= IEEE80211_RATE_BASIC;
  87                 } else switch (mode->mode) {
  88                 case MODE_IEEE80211A:
  89                         if (rate->rate == 60 || rate->rate == 120 ||
  90                             rate->rate == 240)
  91                                 rate->flags |= IEEE80211_RATE_BASIC;
  92                         break;
  93                 case MODE_IEEE80211B:
  94                         if (rate->rate == 10 || rate->rate == 20)
  95                                 rate->flags |= IEEE80211_RATE_BASIC;
  96                         break;
  97                 case MODE_IEEE80211G:
  98                         if (rate->rate == 10 || rate->rate == 20 ||
  99                             rate->rate == 55 || rate->rate == 110)
 100                                 rate->flags |= IEEE80211_RATE_BASIC;
 101                         break;
 102                 case NUM_IEEE80211_MODES:
 103                         /* not useful */
 104                         break;
 105                 }
 106
 107                 /* Set ERP and MANDATORY flags based on phymode */
 108                 switch (mode->mode) {
 109                 case MODE_IEEE80211A:
 110                         if (rate->rate == 60 || rate->rate == 120 ||
 111                             rate->rate == 240)
 112                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 113                         break;
 114                 case MODE_IEEE80211B:
 115                         if (rate->rate == 10)
 116                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 117                         break;
 118                 case MODE_IEEE80211G:
 119                         if (rate->rate == 10 || rate->rate == 20 ||
 120                             rate->rate == 55 || rate->rate == 110 ||
 121                             rate->rate == 60 || rate->rate == 120 ||
 122                             rate->rate == 240)
 123                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 124                         break;
 125                 case NUM_IEEE80211_MODES:
 126                         /* not useful */
 127                         break;
 128                 }
 129                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 130                         rate->flags |= IEEE80211_RATE_ERP;
 131         }
 132 }
 133
 134 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 135 {
 136         u16 fc;
 137
 138         if (len < 24)
 139                 return NULL;
 140
 141         fc = le16_to_cpu(hdr->frame_control);
 142
 143         switch (fc & IEEE80211_FCTL_FTYPE) {
 144         case IEEE80211_FTYPE_DATA:
 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                 return hdr->addr3;
 158         case IEEE80211_FTYPE_CTL:
 159                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 160                         return hdr->addr1;
 161                 else
 162                         return NULL;
 163         }
 164
 165         return NULL;
 166 }
 167
 168 int ieee80211_get_hdrlen(u16 fc)
 169 {
 170         int hdrlen = 24;
 171
 172         switch (fc & IEEE80211_FCTL_FTYPE) {
 173         case IEEE80211_FTYPE_DATA:
 174                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 175                         hdrlen = 30; /* Addr4 */
 176                 /*
 177                  * The QoS Control field is two bytes and its presence is
 178                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 179                  * hdrlen if that bit is set.
 180                  * This works by masking out the bit and shifting it to
 181                  * bit position 1 so the result has the value 0 or 2.
 182                  */
 183                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 184                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 185                 break;
 186         case IEEE80211_FTYPE_CTL:
 187                 /*
 188                  * ACK and CTS are 10 bytes, all others 16. To see how
 189                  * to get this condition consider
 190                  *   subtype mask:   0b0000000011110000 (0x00F0)
 191                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 192                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 193                  *   bits that matter:         ^^^      (0x00E0)
 194                  *   value of those: 0b0000000011000000 (0x00C0)
 195                  */
 196                 if ((fc & 0xE0) == 0xC0)
 197                         hdrlen = 10;
 198                 else
 199                         hdrlen = 16;
 200                 break;
 201         }
 202
 203         return hdrlen;
 204 }
 205 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 206
 207 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 208 {
 209         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 210         int hdrlen;
 211
 212         if (unlikely(skb->len < 10))
 213                 return 0;
 214         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 215         if (unlikely(hdrlen > skb->len))
 216                 return 0;
 217         return hdrlen;
 218 }
 219 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 220
 221 int ieee80211_is_eapol(const struct sk_buff *skb, int hdrlen)
 222 {
 223         if (unlikely(skb->len < 10))
 224                 return 0;
 225
 226         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 227                      memcmp(skb->data + hdrlen, eapol_header,
 228                             sizeof(eapol_header)) == 0))
 229                 return 1;
 230
 231         return 0;
 232 }
 233
 234 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 235 {
 236         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 237
 238         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 239         if (tx->u.tx.extra_frag) {
 240                 struct ieee80211_hdr *fhdr;
 241                 int i;
 242                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 243                         fhdr = (struct ieee80211_hdr *)
 244                                 tx->u.tx.extra_frag[i]->data;
 245                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 246                 }
 247         }
 248 }
 249
 250 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 251                              int rate, int erp, int short_preamble)
 252 {
 253         int dur;
 254
 255         /* calculate duration (in microseconds, rounded up to next higher
 256          * integer if it includes a fractional microsecond) to send frame of
 257          * len bytes (does not include FCS) at the given rate. Duration will
 258          * also include SIFS.
 259          *
 260          * rate is in 100 kbps, so divident is multiplied by 10 in the
 261          * DIV_ROUND_UP() operations.
 262          */
 263
 264         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 265                 /*
 266                  * OFDM:
 267                  *
 268                  * N_DBPS = DATARATE x 4
 269                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 270                  *      (16 = SIGNAL time, 6 = tail bits)
 271                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 272                  *
 273                  * T_SYM = 4 usec
 274                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 275                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 276                  *      signal ext = 6 usec
 277                  */
 278                 dur = 16; /* SIFS + signal ext */
 279                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 280                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 281                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 282                                         4 * rate); /* T_SYM x N_SYM */
 283         } else {
 284                 /*
 285                  * 802.11b or 802.11g with 802.11b compatibility:
 286                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 287                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 288                  *
 289                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 290                  * aSIFSTime = 10 usec
 291                  * aPreambleLength = 144 usec or 72 usec with short preamble
 292                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 293                  */
 294                 dur = 10; /* aSIFSTime = 10 usec */
 295                 dur += short_preamble ? (72 + 24) : (144 + 48);
 296
 297                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 298         }
 299
 300         return dur;
 301 }
 302
 303 /* Exported duration function for driver use */
 304 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 305                                         size_t frame_len, int rate)
 306 {
 307         struct ieee80211_local *local = hw_to_local(hw);
 308         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 309         struct ieee80211_sub_if_data *sdata;
 310         u16 dur;
 311         int erp;
 312
 313         if (unlikely(!bdev))
 314                 return 0;
 315
 316         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 317         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 318         dur = ieee80211_frame_duration(local, frame_len, rate,
 319                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 320
 321         dev_put(bdev);
 322         return cpu_to_le16(dur);
 323 }
 324 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 325
 326 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 327                               size_t frame_len,
 328                               const struct ieee80211_tx_control *frame_txctl)
 329 {
 330         struct ieee80211_local *local = hw_to_local(hw);
 331         struct ieee80211_rate *rate;
 332         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 333         struct ieee80211_sub_if_data *sdata;
 334         int short_preamble;
 335         int erp;
 336         u16 dur;
 337
 338         if (unlikely(!bdev))
 339                 return 0;
 340
 341         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 342         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 343
 344         rate = frame_txctl->rts_rate;
 345         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 346
 347         /* CTS duration */
 348         dur = ieee80211_frame_duration(local, 10, rate->rate,
 349                                        erp, short_preamble);
 350         /* Data frame duration */
 351         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 352                                         erp, short_preamble);
 353         /* ACK duration */
 354         dur += ieee80211_frame_duration(local, 10, rate->rate,
 355                                         erp, short_preamble);
 356
 357         dev_put(bdev);
 358         return cpu_to_le16(dur);
 359 }
 360 EXPORT_SYMBOL(ieee80211_rts_duration);
 361
 362 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 363                                     size_t frame_len,
 364                                     const struct ieee80211_tx_control *frame_txctl)
 365 {
 366         struct ieee80211_local *local = hw_to_local(hw);
 367         struct ieee80211_rate *rate;
 368         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 369         struct ieee80211_sub_if_data *sdata;
 370         int short_preamble;
 371         int erp;
 372         u16 dur;
 373
 374         if (unlikely(!bdev))
 375                 return 0;
 376
 377         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 378         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 379
 380         rate = frame_txctl->rts_rate;
 381         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 382
 383         /* Data frame duration */
 384         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 385                                        erp, short_preamble);
 386         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 387                 /* ACK duration */
 388                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 389                                                 erp, short_preamble);
 390         }
 391
 392         dev_put(bdev);
 393         return cpu_to_le16(dur);
 394 }
 395 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 396
 397 struct ieee80211_rate *
 398 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 399 {
 400         struct ieee80211_hw_mode *mode;
 401         int r;
 402
 403         list_for_each_entry(mode, &local->modes_list, list) {
 404                 if (mode->mode != phymode)
 405                         continue;
 406                 for (r = 0; r < mode->num_rates; r++) {
 407                         struct ieee80211_rate *rate = &mode->rates[r];
 408                         if (rate->val == hw_rate ||
 409                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 410                              rate->val2 == hw_rate))
 411                                 return rate;
 412                 }
 413         }
 414
 415         return NULL;
 416 }
 417
 418 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 419 {
 420         struct ieee80211_local *local = hw_to_local(hw);
 421
 422         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 423                                &local->state[queue])) {
 424                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 425                              &local->state[queue]))
 426                         tasklet_schedule(&local->tx_pending_tasklet);
 427                 else
 428                         if (!ieee80211_qdisc_installed(local->mdev)) {
 429                                 if (queue == 0)
 430                                         netif_wake_queue(local->mdev);
 431                         } else
 432                                 __netif_schedule(local->mdev);
 433         }
 434 }
 435 EXPORT_SYMBOL(ieee80211_wake_queue);
 436
 437 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 438 {
 439         struct ieee80211_local *local = hw_to_local(hw);
 440
 441         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 442                 netif_stop_queue(local->mdev);
 443         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 444 }
 445 EXPORT_SYMBOL(ieee80211_stop_queue);
 446
 447 void ieee80211_start_queues(struct ieee80211_hw *hw)
 448 {
 449         struct ieee80211_local *local = hw_to_local(hw);
 450         int i;
 451
 452         for (i = 0; i < local->hw.queues; i++)
 453                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 454         if (!ieee80211_qdisc_installed(local->mdev))
 455                 netif_start_queue(local->mdev);
 456 }
 457 EXPORT_SYMBOL(ieee80211_start_queues);
 458
 459 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 460 {
 461         int i;
 462
 463         for (i = 0; i < hw->queues; i++)
 464                 ieee80211_stop_queue(hw, i);
 465 }
 466 EXPORT_SYMBOL(ieee80211_stop_queues);
 467
 468 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 469 {
 470         int i;
 471
 472         for (i = 0; i < hw->queues; i++)
 473                 ieee80211_wake_queue(hw, i);
 474 }
 475 EXPORT_SYMBOL(ieee80211_wake_queues);
 476
 477 void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw,
 478                                          void (*iterator)(void *data, u8 *mac,
 479                                                           int if_id),
 480                                          void *data)
 481 {
 482         struct ieee80211_local *local = hw_to_local(hw);
 483         struct ieee80211_sub_if_data *sdata;
 484
 485         rcu_read_lock();
 486
 487         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 488                 switch (sdata->type) {
 489                 case IEEE80211_IF_TYPE_INVALID:
 490                 case IEEE80211_IF_TYPE_MNTR:
 491                 case IEEE80211_IF_TYPE_VLAN:
 492                         continue;
 493                 case IEEE80211_IF_TYPE_AP:
 494                 case IEEE80211_IF_TYPE_STA:
 495                 case IEEE80211_IF_TYPE_IBSS:
 496                 case IEEE80211_IF_TYPE_WDS:
 497                         break;
 498                 }
 499                 if (sdata->dev == local->mdev)
 500                         continue;
 501                 if (netif_running(sdata->dev))
 502                         iterator(data, sdata->dev->dev_addr,
 503                                  sdata->dev->ifindex);
 504         }
 505
 506         rcu_read_unlock();
 507 }
 508 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);