Pileus Git - ~andy/linux/blob - 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_ATHEROS_TURBO:
  97                         if (rate->rate == 120 || rate->rate == 240 ||
  98                             rate->rate == 480)
  99                                 rate->flags |= IEEE80211_RATE_BASIC;
 100                         break;
 101                 case MODE_IEEE80211G:
 102                         if (rate->rate == 10 || rate->rate == 20 ||
 103                             rate->rate == 55 || rate->rate == 110)
 104                                 rate->flags |= IEEE80211_RATE_BASIC;
 105                         break;
 106                 }
 107
 108                 /* Set ERP and MANDATORY flags based on phymode */
 109                 switch (mode->mode) {
 110                 case MODE_IEEE80211A:
 111                         if (rate->rate == 60 || rate->rate == 120 ||
 112                             rate->rate == 240)
 113                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 114                         break;
 115                 case MODE_IEEE80211B:
 116                         if (rate->rate == 10)
 117                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 118                         break;
 119                 case MODE_ATHEROS_TURBO:
 120                         break;
 121                 case MODE_IEEE80211G:
 122                         if (rate->rate == 10 || rate->rate == 20 ||
 123                             rate->rate == 55 || rate->rate == 110 ||
 124                             rate->rate == 60 || rate->rate == 120 ||
 125                             rate->rate == 240)
 126                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 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)
 222 {
 223         const struct ieee80211_hdr *hdr;
 224         u16 fc;
 225         int hdrlen;
 226
 227         if (unlikely(skb->len < 10))
 228                 return 0;
 229
 230         hdr = (const struct ieee80211_hdr *) skb->data;
 231         fc = le16_to_cpu(hdr->frame_control);
 232
 233         if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
 234                 return 0;
 235
 236         hdrlen = ieee80211_get_hdrlen(fc);
 237
 238         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 239                      memcmp(skb->data + hdrlen, eapol_header,
 240                             sizeof(eapol_header)) == 0))
 241                 return 1;
 242
 243         return 0;
 244 }
 245
 246 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 247 {
 248         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 249
 250         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 251         if (tx->u.tx.extra_frag) {
 252                 struct ieee80211_hdr *fhdr;
 253                 int i;
 254                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 255                         fhdr = (struct ieee80211_hdr *)
 256                                 tx->u.tx.extra_frag[i]->data;
 257                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 258                 }
 259         }
 260 }
 261
 262 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 263                              int rate, int erp, int short_preamble)
 264 {
 265         int dur;
 266
 267         /* calculate duration (in microseconds, rounded up to next higher
 268          * integer if it includes a fractional microsecond) to send frame of
 269          * len bytes (does not include FCS) at the given rate. Duration will
 270          * also include SIFS.
 271          *
 272          * rate is in 100 kbps, so divident is multiplied by 10 in the
 273          * DIV_ROUND_UP() operations.
 274          */
 275
 276         if (local->hw.conf.phymode == MODE_IEEE80211A || erp ||
 277             local->hw.conf.phymode == MODE_ATHEROS_TURBO) {
 278                 /*
 279                  * OFDM:
 280                  *
 281                  * N_DBPS = DATARATE x 4
 282                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 283                  *      (16 = SIGNAL time, 6 = tail bits)
 284                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 285                  *
 286                  * T_SYM = 4 usec
 287                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 288                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 289                  *      signal ext = 6 usec
 290                  */
 291                 /* FIX: Atheros Turbo may have different (shorter) duration? */
 292                 dur = 16; /* SIFS + signal ext */
 293                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 294                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 295                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 296                                         4 * rate); /* T_SYM x N_SYM */
 297         } else {
 298                 /*
 299                  * 802.11b or 802.11g with 802.11b compatibility:
 300                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 301                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 302                  *
 303                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 304                  * aSIFSTime = 10 usec
 305                  * aPreambleLength = 144 usec or 72 usec with short preamble
 306                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 307                  */
 308                 dur = 10; /* aSIFSTime = 10 usec */
 309                 dur += short_preamble ? (72 + 24) : (144 + 48);
 310
 311                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 312         }
 313
 314         return dur;
 315 }
 316
 317 /* Exported duration function for driver use */
 318 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 319                                         size_t frame_len, int rate)
 320 {
 321         struct ieee80211_local *local = hw_to_local(hw);
 322         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 323         struct ieee80211_sub_if_data *sdata;
 324         u16 dur;
 325         int erp;
 326
 327         if (unlikely(!bdev))
 328                 return 0;
 329
 330         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 331         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 332         dur = ieee80211_frame_duration(local, frame_len, rate,
 333                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 334
 335         dev_put(bdev);
 336         return cpu_to_le16(dur);
 337 }
 338 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 339
 340 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 341                               size_t frame_len,
 342                               const struct ieee80211_tx_control *frame_txctl)
 343 {
 344         struct ieee80211_local *local = hw_to_local(hw);
 345         struct ieee80211_rate *rate;
 346         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 347         struct ieee80211_sub_if_data *sdata;
 348         int short_preamble;
 349         int erp;
 350         u16 dur;
 351
 352         if (unlikely(!bdev))
 353                 return 0;
 354
 355         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 356         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 357
 358         rate = frame_txctl->rts_rate;
 359         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 360
 361         /* CTS duration */
 362         dur = ieee80211_frame_duration(local, 10, rate->rate,
 363                                        erp, short_preamble);
 364         /* Data frame duration */
 365         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 366                                         erp, short_preamble);
 367         /* ACK duration */
 368         dur += ieee80211_frame_duration(local, 10, rate->rate,
 369                                         erp, short_preamble);
 370
 371         dev_put(bdev);
 372         return cpu_to_le16(dur);
 373 }
 374 EXPORT_SYMBOL(ieee80211_rts_duration);
 375
 376 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 377                                     size_t frame_len,
 378                                     const struct ieee80211_tx_control *frame_txctl)
 379 {
 380         struct ieee80211_local *local = hw_to_local(hw);
 381         struct ieee80211_rate *rate;
 382         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 383         struct ieee80211_sub_if_data *sdata;
 384         int short_preamble;
 385         int erp;
 386         u16 dur;
 387
 388         if (unlikely(!bdev))
 389                 return 0;
 390
 391         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 392         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 393
 394         rate = frame_txctl->rts_rate;
 395         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 396
 397         /* Data frame duration */
 398         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 399                                        erp, short_preamble);
 400         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 401                 /* ACK duration */
 402                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 403                                                 erp, short_preamble);
 404         }
 405
 406         dev_put(bdev);
 407         return cpu_to_le16(dur);
 408 }
 409 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 410
 411 struct ieee80211_rate *
 412 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 413 {
 414         struct ieee80211_hw_mode *mode;
 415         int r;
 416
 417         list_for_each_entry(mode, &local->modes_list, list) {
 418                 if (mode->mode != phymode)
 419                         continue;
 420                 for (r = 0; r < mode->num_rates; r++) {
 421                         struct ieee80211_rate *rate = &mode->rates[r];
 422                         if (rate->val == hw_rate ||
 423                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 424                              rate->val2 == hw_rate))
 425                                 return rate;
 426                 }
 427         }
 428
 429         return NULL;
 430 }
 431
 432 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 433 {
 434         struct ieee80211_local *local = hw_to_local(hw);
 435
 436         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 437                                &local->state[queue])) {
 438                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 439                              &local->state[queue]))
 440                         tasklet_schedule(&local->tx_pending_tasklet);
 441                 else
 442                         if (!ieee80211_qdisc_installed(local->mdev)) {
 443                                 if (queue == 0)
 444                                         netif_wake_queue(local->mdev);
 445                         } else
 446                                 __netif_schedule(local->mdev);
 447         }
 448 }
 449 EXPORT_SYMBOL(ieee80211_wake_queue);
 450
 451 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 452 {
 453         struct ieee80211_local *local = hw_to_local(hw);
 454
 455         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 456                 netif_stop_queue(local->mdev);
 457         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 458 }
 459 EXPORT_SYMBOL(ieee80211_stop_queue);
 460
 461 void ieee80211_start_queues(struct ieee80211_hw *hw)
 462 {
 463         struct ieee80211_local *local = hw_to_local(hw);
 464         int i;
 465
 466         for (i = 0; i < local->hw.queues; i++)
 467                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 468         if (!ieee80211_qdisc_installed(local->mdev))
 469                 netif_start_queue(local->mdev);
 470 }
 471 EXPORT_SYMBOL(ieee80211_start_queues);
 472
 473 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 474 {
 475         int i;
 476
 477         for (i = 0; i < hw->queues; i++)
 478                 ieee80211_stop_queue(hw, i);
 479 }
 480 EXPORT_SYMBOL(ieee80211_stop_queues);
 481
 482 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 483 {
 484         int i;
 485
 486         for (i = 0; i < hw->queues; i++)
 487                 ieee80211_wake_queue(hw, i);
 488 }
 489 EXPORT_SYMBOL(ieee80211_wake_queues);