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
  26 #include "ieee80211_i.h"
  27 #include "ieee80211_rate.h"
  28 #include "wme.h"
  29
  30 /* privid for wiphys to determine whether they belong to us or not */
  31 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
  32
  33 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
  34 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
  35 const unsigned char rfc1042_header[] =
  36         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  37
  38 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  39 const unsigned char bridge_tunnel_header[] =
  40         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  41
  42 /* No encapsulation header if EtherType < 0x600 (=length) */
  43 static const unsigned char eapol_header[] =
  44         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
  45
  46
  47 static int rate_list_match(const int *rate_list, int rate)
  48 {
  49         int i;
  50
  51         if (!rate_list)
  52                 return 0;
  53
  54         for (i = 0; rate_list[i] >= 0; i++)
  55                 if (rate_list[i] == rate)
  56                         return 1;
  57
  58         return 0;
  59 }
  60
  61 void ieee80211_prepare_rates(struct ieee80211_local *local,
  62                              struct ieee80211_hw_mode *mode)
  63 {
  64         int i;
  65
  66         for (i = 0; i < mode->num_rates; i++) {
  67                 struct ieee80211_rate *rate = &mode->rates[i];
  68
  69                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
  70                                  IEEE80211_RATE_BASIC);
  71
  72                 if (local->supp_rates[mode->mode]) {
  73                         if (!rate_list_match(local->supp_rates[mode->mode],
  74                                              rate->rate))
  75                                 continue;
  76                 }
  77
  78                 rate->flags |= IEEE80211_RATE_SUPPORTED;
  79
  80                 /* Use configured basic rate set if it is available. If not,
  81                  * use defaults that are sane for most cases. */
  82                 if (local->basic_rates[mode->mode]) {
  83                         if (rate_list_match(local->basic_rates[mode->mode],
  84                                             rate->rate))
  85                                 rate->flags |= IEEE80211_RATE_BASIC;
  86                 } else switch (mode->mode) {
  87                 case MODE_IEEE80211A:
  88                         if (rate->rate == 60 || rate->rate == 120 ||
  89                             rate->rate == 240)
  90                                 rate->flags |= IEEE80211_RATE_BASIC;
  91                         break;
  92                 case MODE_IEEE80211B:
  93                         if (rate->rate == 10 || rate->rate == 20)
  94                                 rate->flags |= IEEE80211_RATE_BASIC;
  95                         break;
  96                 case MODE_IEEE80211G:
  97                         if (rate->rate == 10 || rate->rate == 20 ||
  98                             rate->rate == 55 || rate->rate == 110)
  99                                 rate->flags |= IEEE80211_RATE_BASIC;
 100                         break;
 101                 case NUM_IEEE80211_MODES:
 102                         /* not useful */
 103                         break;
 104                 }
 105
 106                 /* Set ERP and MANDATORY flags based on phymode */
 107                 switch (mode->mode) {
 108                 case MODE_IEEE80211A:
 109                         if (rate->rate == 60 || rate->rate == 120 ||
 110                             rate->rate == 240)
 111                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 112                         break;
 113                 case MODE_IEEE80211B:
 114                         if (rate->rate == 10)
 115                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 116                         break;
 117                 case MODE_IEEE80211G:
 118                         if (rate->rate == 10 || rate->rate == 20 ||
 119                             rate->rate == 55 || rate->rate == 110 ||
 120                             rate->rate == 60 || rate->rate == 120 ||
 121                             rate->rate == 240)
 122                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 123                         break;
 124                 case NUM_IEEE80211_MODES:
 125                         /* not useful */
 126                         break;
 127                 }
 128                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 129                         rate->flags |= IEEE80211_RATE_ERP;
 130         }
 131 }
 132
 133 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 134 {
 135         u16 fc;
 136
 137         if (len < 24)
 138                 return NULL;
 139
 140         fc = le16_to_cpu(hdr->frame_control);
 141
 142         switch (fc & IEEE80211_FCTL_FTYPE) {
 143         case IEEE80211_FTYPE_DATA:
 144                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 145                 case IEEE80211_FCTL_TODS:
 146                         return hdr->addr1;
 147                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
 148                         return NULL;
 149                 case IEEE80211_FCTL_FROMDS:
 150                         return hdr->addr2;
 151                 case 0:
 152                         return hdr->addr3;
 153                 }
 154                 break;
 155         case IEEE80211_FTYPE_MGMT:
 156                 return hdr->addr3;
 157         case IEEE80211_FTYPE_CTL:
 158                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 159                         return hdr->addr1;
 160                 else
 161                         return NULL;
 162         }
 163
 164         return NULL;
 165 }
 166
 167 int ieee80211_get_hdrlen(u16 fc)
 168 {
 169         int hdrlen = 24;
 170
 171         switch (fc & IEEE80211_FCTL_FTYPE) {
 172         case IEEE80211_FTYPE_DATA:
 173                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 174                         hdrlen = 30; /* Addr4 */
 175                 /*
 176                  * The QoS Control field is two bytes and its presence is
 177                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 178                  * hdrlen if that bit is set.
 179                  * This works by masking out the bit and shifting it to
 180                  * bit position 1 so the result has the value 0 or 2.
 181                  */
 182                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 183                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 184                 break;
 185         case IEEE80211_FTYPE_CTL:
 186                 /*
 187                  * ACK and CTS are 10 bytes, all others 16. To see how
 188                  * to get this condition consider
 189                  *   subtype mask:   0b0000000011110000 (0x00F0)
 190                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 191                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 192                  *   bits that matter:         ^^^      (0x00E0)
 193                  *   value of those: 0b0000000011000000 (0x00C0)
 194                  */
 195                 if ((fc & 0xE0) == 0xC0)
 196                         hdrlen = 10;
 197                 else
 198                         hdrlen = 16;
 199                 break;
 200         }
 201
 202         return hdrlen;
 203 }
 204 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 205
 206 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 207 {
 208         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 209         int hdrlen;
 210
 211         if (unlikely(skb->len < 10))
 212                 return 0;
 213         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 214         if (unlikely(hdrlen > skb->len))
 215                 return 0;
 216         return hdrlen;
 217 }
 218 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 219
 220 int ieee80211_is_eapol(const struct sk_buff *skb)
 221 {
 222         const struct ieee80211_hdr *hdr;
 223         u16 fc;
 224         int hdrlen;
 225
 226         if (unlikely(skb->len < 10))
 227                 return 0;
 228
 229         hdr = (const struct ieee80211_hdr *) skb->data;
 230         fc = le16_to_cpu(hdr->frame_control);
 231
 232         if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
 233                 return 0;
 234
 235         hdrlen = ieee80211_get_hdrlen(fc);
 236
 237         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 238                      memcmp(skb->data + hdrlen, eapol_header,
 239                             sizeof(eapol_header)) == 0))
 240                 return 1;
 241
 242         return 0;
 243 }
 244
 245 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 246 {
 247         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 248
 249         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 250         if (tx->u.tx.extra_frag) {
 251                 struct ieee80211_hdr *fhdr;
 252                 int i;
 253                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 254                         fhdr = (struct ieee80211_hdr *)
 255                                 tx->u.tx.extra_frag[i]->data;
 256                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 257                 }
 258         }
 259 }
 260
 261 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 262                              int rate, int erp, int short_preamble)
 263 {
 264         int dur;
 265
 266         /* calculate duration (in microseconds, rounded up to next higher
 267          * integer if it includes a fractional microsecond) to send frame of
 268          * len bytes (does not include FCS) at the given rate. Duration will
 269          * also include SIFS.
 270          *
 271          * rate is in 100 kbps, so divident is multiplied by 10 in the
 272          * DIV_ROUND_UP() operations.
 273          */
 274
 275         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 276                 /*
 277                  * OFDM:
 278                  *
 279                  * N_DBPS = DATARATE x 4
 280                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 281                  *      (16 = SIGNAL time, 6 = tail bits)
 282                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 283                  *
 284                  * T_SYM = 4 usec
 285                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 286                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 287                  *      signal ext = 6 usec
 288                  */
 289                 dur = 16; /* SIFS + signal ext */
 290                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 291                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 292                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 293                                         4 * rate); /* T_SYM x N_SYM */
 294         } else {
 295                 /*
 296                  * 802.11b or 802.11g with 802.11b compatibility:
 297                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 298                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 299                  *
 300                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 301                  * aSIFSTime = 10 usec
 302                  * aPreambleLength = 144 usec or 72 usec with short preamble
 303                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 304                  */
 305                 dur = 10; /* aSIFSTime = 10 usec */
 306                 dur += short_preamble ? (72 + 24) : (144 + 48);
 307
 308                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 309         }
 310
 311         return dur;
 312 }
 313
 314 /* Exported duration function for driver use */
 315 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 316                                         size_t frame_len, int rate)
 317 {
 318         struct ieee80211_local *local = hw_to_local(hw);
 319         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 320         struct ieee80211_sub_if_data *sdata;
 321         u16 dur;
 322         int erp;
 323
 324         if (unlikely(!bdev))
 325                 return 0;
 326
 327         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 328         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 329         dur = ieee80211_frame_duration(local, frame_len, rate,
 330                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 331
 332         dev_put(bdev);
 333         return cpu_to_le16(dur);
 334 }
 335 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 336
 337 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 338                               size_t frame_len,
 339                               const struct ieee80211_tx_control *frame_txctl)
 340 {
 341         struct ieee80211_local *local = hw_to_local(hw);
 342         struct ieee80211_rate *rate;
 343         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 344         struct ieee80211_sub_if_data *sdata;
 345         int short_preamble;
 346         int erp;
 347         u16 dur;
 348
 349         if (unlikely(!bdev))
 350                 return 0;
 351
 352         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 353         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 354
 355         rate = frame_txctl->rts_rate;
 356         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 357
 358         /* CTS duration */
 359         dur = ieee80211_frame_duration(local, 10, rate->rate,
 360                                        erp, short_preamble);
 361         /* Data frame duration */
 362         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 363                                         erp, short_preamble);
 364         /* ACK duration */
 365         dur += ieee80211_frame_duration(local, 10, rate->rate,
 366                                         erp, short_preamble);
 367
 368         dev_put(bdev);
 369         return cpu_to_le16(dur);
 370 }
 371 EXPORT_SYMBOL(ieee80211_rts_duration);
 372
 373 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 374                                     size_t frame_len,
 375                                     const struct ieee80211_tx_control *frame_txctl)
 376 {
 377         struct ieee80211_local *local = hw_to_local(hw);
 378         struct ieee80211_rate *rate;
 379         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 380         struct ieee80211_sub_if_data *sdata;
 381         int short_preamble;
 382         int erp;
 383         u16 dur;
 384
 385         if (unlikely(!bdev))
 386                 return 0;
 387
 388         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 389         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 390
 391         rate = frame_txctl->rts_rate;
 392         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 393
 394         /* Data frame duration */
 395         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 396                                        erp, short_preamble);
 397         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 398                 /* ACK duration */
 399                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 400                                                 erp, short_preamble);
 401         }
 402
 403         dev_put(bdev);
 404         return cpu_to_le16(dur);
 405 }
 406 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 407
 408 struct ieee80211_rate *
 409 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 410 {
 411         struct ieee80211_hw_mode *mode;
 412         int r;
 413
 414         list_for_each_entry(mode, &local->modes_list, list) {
 415                 if (mode->mode != phymode)
 416                         continue;
 417                 for (r = 0; r < mode->num_rates; r++) {
 418                         struct ieee80211_rate *rate = &mode->rates[r];
 419                         if (rate->val == hw_rate ||
 420                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 421                              rate->val2 == hw_rate))
 422                                 return rate;
 423                 }
 424         }
 425
 426         return NULL;
 427 }
 428
 429 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 430 {
 431         struct ieee80211_local *local = hw_to_local(hw);
 432
 433         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 434                                &local->state[queue])) {
 435                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 436                              &local->state[queue]))
 437                         tasklet_schedule(&local->tx_pending_tasklet);
 438                 else
 439                         if (!ieee80211_qdisc_installed(local->mdev)) {
 440                                 if (queue == 0)
 441                                         netif_wake_queue(local->mdev);
 442                         } else
 443                                 __netif_schedule(local->mdev);
 444         }
 445 }
 446 EXPORT_SYMBOL(ieee80211_wake_queue);
 447
 448 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 449 {
 450         struct ieee80211_local *local = hw_to_local(hw);
 451
 452         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 453                 netif_stop_queue(local->mdev);
 454         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 455 }
 456 EXPORT_SYMBOL(ieee80211_stop_queue);
 457
 458 void ieee80211_start_queues(struct ieee80211_hw *hw)
 459 {
 460         struct ieee80211_local *local = hw_to_local(hw);
 461         int i;
 462
 463         for (i = 0; i < local->hw.queues; i++)
 464                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 465         if (!ieee80211_qdisc_installed(local->mdev))
 466                 netif_start_queue(local->mdev);
 467 }
 468 EXPORT_SYMBOL(ieee80211_start_queues);
 469
 470 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 471 {
 472         int i;
 473
 474         for (i = 0; i < hw->queues; i++)
 475                 ieee80211_stop_queue(hw, i);
 476 }
 477 EXPORT_SYMBOL(ieee80211_stop_queues);
 478
 479 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 480 {
 481         int i;
 482
 483         for (i = 0; i < hw->queues; i++)
 484                 ieee80211_wake_queue(hw, i);
 485 }
 486 EXPORT_SYMBOL(ieee80211_wake_queues);