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