package/mac80211/src/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/cfg80211.h>
  24
  25 #include "ieee80211_i.h"
  26 #include "ieee80211_rate.h"
  27 #include "wme.h"
  28
  29 /* privid for wiphys to determine whether they belong to us or not */
  30 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
  31
  32 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
  33 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
  34 const unsigned char rfc1042_header[] =
  35         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  36
  37 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  38 const unsigned char bridge_tunnel_header[] =
  39         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  40
  41 /* No encapsulation header if EtherType < 0x600 (=length) */
  42 static const unsigned char eapol_header[] =
  43         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
  44
  45
  46 static int rate_list_match(const int *rate_list, int rate)
  47 {
  48         int i;
  49
  50         if (!rate_list)
  51                 return 0;
  52
  53         for (i = 0; rate_list[i] >= 0; i++)
  54                 if (rate_list[i] == rate)
  55                         return 1;
  56
  57         return 0;
  58 }
  59
  60 void ieee80211_prepare_rates(struct ieee80211_local *local,
  61                              struct ieee80211_hw_mode *mode)
  62 {
  63         int i;
  64
  65         for (i = 0; i < mode->num_rates; i++) {
  66                 struct ieee80211_rate *rate = &mode->rates[i];
  67
  68                 rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
  69                                  IEEE80211_RATE_BASIC);
  70
  71                 if (local->supp_rates[mode->mode]) {
  72                         if (!rate_list_match(local->supp_rates[mode->mode],
  73                                              rate->rate))
  74                                 continue;
  75                 }
  76
  77                 rate->flags |= IEEE80211_RATE_SUPPORTED;
  78
  79                 /* Use configured basic rate set if it is available. If not,
  80                  * use defaults that are sane for most cases. */
  81                 if (local->basic_rates[mode->mode]) {
  82                         if (rate_list_match(local->basic_rates[mode->mode],
  83                                             rate->rate))
  84                                 rate->flags |= IEEE80211_RATE_BASIC;
  85                 } else switch (mode->mode) {
  86                 case MODE_IEEE80211A:
  87                         if (rate->rate == 60 || rate->rate == 120 ||
  88                             rate->rate == 240)
  89                                 rate->flags |= IEEE80211_RATE_BASIC;
  90                         break;
  91                 case MODE_IEEE80211B:
  92                         if (rate->rate == 10 || rate->rate == 20)
  93                                 rate->flags |= IEEE80211_RATE_BASIC;
  94                         break;
  95                 case MODE_IEEE80211G:
  96                         if (rate->rate == 10 || rate->rate == 20 ||
  97                             rate->rate == 55 || rate->rate == 110)
  98                                 rate->flags |= IEEE80211_RATE_BASIC;
  99                         break;
 100                 case NUM_IEEE80211_MODES:
 101                         /* not useful */
 102                         break;
 103                 }
 104
 105                 /* Set ERP and MANDATORY flags based on phymode */
 106                 switch (mode->mode) {
 107                 case MODE_IEEE80211A:
 108                         if (rate->rate == 60 || rate->rate == 120 ||
 109                             rate->rate == 240)
 110                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 111                         break;
 112                 case MODE_IEEE80211B:
 113                         if (rate->rate == 10)
 114                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 115                         break;
 116                 case MODE_IEEE80211G:
 117                         if (rate->rate == 10 || rate->rate == 20 ||
 118                             rate->rate == 55 || rate->rate == 110 ||
 119                             rate->rate == 60 || rate->rate == 120 ||
 120                             rate->rate == 240)
 121                                 rate->flags |= IEEE80211_RATE_MANDATORY;
 122                         break;
 123                 case NUM_IEEE80211_MODES:
 124                         /* not useful */
 125                         break;
 126                 }
 127                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 128                         rate->flags |= IEEE80211_RATE_ERP;
 129         }
 130 }
 131
 132 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 133 {
 134         u16 fc;
 135
 136         if (len < 24)
 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                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 144                 case IEEE80211_FCTL_TODS:
 145                         return hdr->addr1;
 146                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
 147                         return NULL;
 148                 case IEEE80211_FCTL_FROMDS:
 149                         return hdr->addr2;
 150                 case 0:
 151                         return hdr->addr3;
 152                 }
 153                 break;
 154         case IEEE80211_FTYPE_MGMT:
 155                 return hdr->addr3;
 156         case IEEE80211_FTYPE_CTL:
 157                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 158                         return hdr->addr1;
 159                 else
 160                         return NULL;
 161         }
 162
 163         return NULL;
 164 }
 165
 166 int ieee80211_get_hdrlen(u16 fc)
 167 {
 168         int hdrlen = 24;
 169
 170         switch (fc & IEEE80211_FCTL_FTYPE) {
 171         case IEEE80211_FTYPE_DATA:
 172                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 173                         hdrlen = 30; /* Addr4 */
 174                 /*
 175                  * The QoS Control field is two bytes and its presence is
 176                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 177                  * hdrlen if that bit is set.
 178                  * This works by masking out the bit and shifting it to
 179                  * bit position 1 so the result has the value 0 or 2.
 180                  */
 181                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 182                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 183                 break;
 184         case IEEE80211_FTYPE_CTL:
 185                 /*
 186                  * ACK and CTS are 10 bytes, all others 16. To see how
 187                  * to get this condition consider
 188                  *   subtype mask:   0b0000000011110000 (0x00F0)
 189                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 190                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 191                  *   bits that matter:         ^^^      (0x00E0)
 192                  *   value of those: 0b0000000011000000 (0x00C0)
 193                  */
 194                 if ((fc & 0xE0) == 0xC0)
 195                         hdrlen = 10;
 196                 else
 197                         hdrlen = 16;
 198                 break;
 199         }
 200
 201         return hdrlen;
 202 }
 203 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 204
 205 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 206 {
 207         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 208         int hdrlen;
 209
 210         if (unlikely(skb->len < 10))
 211                 return 0;
 212         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 213         if (unlikely(hdrlen > skb->len))
 214                 return 0;
 215         return hdrlen;
 216 }
 217 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 218
 219 int ieee80211_is_eapol(const struct sk_buff *skb)
 220 {
 221         const struct ieee80211_hdr *hdr;
 222         u16 fc;
 223         int hdrlen;
 224
 225         if (unlikely(skb->len < 10))
 226                 return 0;
 227
 228         hdr = (const struct ieee80211_hdr *) skb->data;
 229         fc = le16_to_cpu(hdr->frame_control);
 230
 231         if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
 232                 return 0;
 233
 234         hdrlen = ieee80211_get_hdrlen(fc);
 235
 236         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 237                      memcmp(skb->data + hdrlen, eapol_header,
 238                             sizeof(eapol_header)) == 0))
 239                 return 1;
 240
 241         return 0;
 242 }
 243
 244 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 245 {
 246         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 247
 248         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 249         if (tx->u.tx.extra_frag) {
 250                 struct ieee80211_hdr *fhdr;
 251                 int i;
 252                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 253                         fhdr = (struct ieee80211_hdr *)
 254                                 tx->u.tx.extra_frag[i]->data;
 255                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 256                 }
 257         }
 258 }
 259
 260 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 261                              int rate, int erp, int short_preamble)
 262 {
 263         int dur;
 264
 265         /* calculate duration (in microseconds, rounded up to next higher
 266          * integer if it includes a fractional microsecond) to send frame of
 267          * len bytes (does not include FCS) at the given rate. Duration will
 268          * also include SIFS.
 269          *
 270          * rate is in 100 kbps, so divident is multiplied by 10 in the
 271          * DIV_ROUND_UP() operations.
 272          */
 273
 274         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 275                 /*
 276                  * OFDM:
 277                  *
 278                  * N_DBPS = DATARATE x 4
 279                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 280                  *      (16 = SIGNAL time, 6 = tail bits)
 281                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 282                  *
 283                  * T_SYM = 4 usec
 284                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 285                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 286                  *      signal ext = 6 usec
 287                  */
 288                 dur = 16; /* SIFS + signal ext */
 289                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 290                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 291                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 292                                         4 * rate); /* T_SYM x N_SYM */
 293         } else {
 294                 /*
 295                  * 802.11b or 802.11g with 802.11b compatibility:
 296                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 297                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 298                  *
 299                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 300                  * aSIFSTime = 10 usec
 301                  * aPreambleLength = 144 usec or 72 usec with short preamble
 302                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 303                  */
 304                 dur = 10; /* aSIFSTime = 10 usec */
 305                 dur += short_preamble ? (72 + 24) : (144 + 48);
 306
 307                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 308         }
 309
 310         return dur;
 311 }
 312
 313 /* Exported duration function for driver use */
 314 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 315                                         size_t frame_len, int rate)
 316 {
 317         struct ieee80211_local *local = hw_to_local(hw);
 318         struct net_device *bdev = dev_get_by_index(if_id);
 319         struct ieee80211_sub_if_data *sdata;
 320         u16 dur;
 321         int erp;
 322
 323         if (unlikely(!bdev))
 324                 return 0;
 325
 326         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 327         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 328         dur = ieee80211_frame_duration(local, frame_len, rate,
 329                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 330
 331         dev_put(bdev);
 332         return cpu_to_le16(dur);
 333 }
 334 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 335
 336 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 337                               size_t frame_len,
 338                               const struct ieee80211_tx_control *frame_txctl)
 339 {
 340         struct ieee80211_local *local = hw_to_local(hw);
 341         struct ieee80211_rate *rate;
 342         struct net_device *bdev = dev_get_by_index(if_id);
 343         struct ieee80211_sub_if_data *sdata;
 344         int short_preamble;
 345         int erp;
 346         u16 dur;
 347
 348         if (unlikely(!bdev))
 349                 return 0;
 350
 351         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 352         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 353
 354         rate = frame_txctl->rts_rate;
 355         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 356
 357         /* CTS duration */
 358         dur = ieee80211_frame_duration(local, 10, rate->rate,
 359                                        erp, short_preamble);
 360         /* Data frame duration */
 361         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 362                                         erp, short_preamble);
 363         /* ACK duration */
 364         dur += ieee80211_frame_duration(local, 10, rate->rate,
 365                                         erp, short_preamble);
 366
 367         dev_put(bdev);
 368         return cpu_to_le16(dur);
 369 }
 370 EXPORT_SYMBOL(ieee80211_rts_duration);
 371
 372 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 373                                     size_t frame_len,
 374                                     const struct ieee80211_tx_control *frame_txctl)
 375 {
 376         struct ieee80211_local *local = hw_to_local(hw);
 377         struct ieee80211_rate *rate;
 378         struct net_device *bdev = dev_get_by_index(if_id);
 379         struct ieee80211_sub_if_data *sdata;
 380         int short_preamble;
 381         int erp;
 382         u16 dur;
 383
 384         if (unlikely(!bdev))
 385                 return 0;
 386
 387         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 388         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 389
 390         rate = frame_txctl->rts_rate;
 391         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 392
 393         /* Data frame duration */
 394         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 395                                        erp, short_preamble);
 396         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 397                 /* ACK duration */
 398                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 399                                                 erp, short_preamble);
 400         }
 401
 402         dev_put(bdev);
 403         return cpu_to_le16(dur);
 404 }
 405 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 406
 407 struct ieee80211_rate *
 408 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 409 {
 410         struct ieee80211_hw_mode *mode;
 411         int r;
 412
 413         list_for_each_entry(mode, &local->modes_list, list) {
 414                 if (mode->mode != phymode)
 415                         continue;
 416                 for (r = 0; r < mode->num_rates; r++) {
 417                         struct ieee80211_rate *rate = &mode->rates[r];
 418                         if (rate->val == hw_rate ||
 419                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 420                              rate->val2 == hw_rate))
 421                                 return rate;
 422                 }
 423         }
 424
 425         return NULL;
 426 }
 427
 428 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 429 {
 430         struct ieee80211_local *local = hw_to_local(hw);
 431
 432         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 433                                &local->state[queue])) {
 434                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 435                              &local->state[queue]))
 436                         tasklet_schedule(&local->tx_pending_tasklet);
 437                 else
 438                         if (!ieee80211_qdisc_installed(local->mdev)) {
 439                                 if (queue == 0)
 440                                         netif_wake_queue(local->mdev);
 441                         } else
 442                                 __netif_schedule(local->mdev);
 443         }
 444 }
 445 EXPORT_SYMBOL(ieee80211_wake_queue);
 446
 447 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 448 {
 449         struct ieee80211_local *local = hw_to_local(hw);
 450
 451         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 452                 netif_stop_queue(local->mdev);
 453         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 454 }
 455 EXPORT_SYMBOL(ieee80211_stop_queue);
 456
 457 void ieee80211_start_queues(struct ieee80211_hw *hw)
 458 {
 459         struct ieee80211_local *local = hw_to_local(hw);
 460         int i;
 461
 462         for (i = 0; i < local->hw.queues; i++)
 463                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 464         if (!ieee80211_qdisc_installed(local->mdev))
 465                 netif_start_queue(local->mdev);
 466 }
 467 EXPORT_SYMBOL(ieee80211_start_queues);
 468
 469 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 470 {
 471         int i;
 472
 473         for (i = 0; i < hw->queues; i++)
 474                 ieee80211_stop_queue(hw, i);
 475 }
 476 EXPORT_SYMBOL(ieee80211_stop_queues);
 477
 478 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 479 {
 480         int i;
 481
 482         for (i = 0; i < hw->queues; i++)
 483                 ieee80211_wake_queue(hw, i);
 484 }
 485 EXPORT_SYMBOL(ieee80211_wake_queues);