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                 }
 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                 }
 122                 if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 123                         rate->flags |= IEEE80211_RATE_ERP;
 124         }
 125 }
 126
 127 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 128 {
 129         u16 fc;
 130
 131         if (len < 24)
 132                 return NULL;
 133
 134         fc = le16_to_cpu(hdr->frame_control);
 135
 136         switch (fc & IEEE80211_FCTL_FTYPE) {
 137         case IEEE80211_FTYPE_DATA:
 138                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 139                 case IEEE80211_FCTL_TODS:
 140                         return hdr->addr1;
 141                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
 142                         return NULL;
 143                 case IEEE80211_FCTL_FROMDS:
 144                         return hdr->addr2;
 145                 case 0:
 146                         return hdr->addr3;
 147                 }
 148                 break;
 149         case IEEE80211_FTYPE_MGMT:
 150                 return hdr->addr3;
 151         case IEEE80211_FTYPE_CTL:
 152                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 153                         return hdr->addr1;
 154                 else
 155                         return NULL;
 156         }
 157
 158         return NULL;
 159 }
 160
 161 int ieee80211_get_hdrlen(u16 fc)
 162 {
 163         int hdrlen = 24;
 164
 165         switch (fc & IEEE80211_FCTL_FTYPE) {
 166         case IEEE80211_FTYPE_DATA:
 167                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 168                         hdrlen = 30; /* Addr4 */
 169                 /*
 170                  * The QoS Control field is two bytes and its presence is
 171                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 172                  * hdrlen if that bit is set.
 173                  * This works by masking out the bit and shifting it to
 174                  * bit position 1 so the result has the value 0 or 2.
 175                  */
 176                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 177                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 178                 break;
 179         case IEEE80211_FTYPE_CTL:
 180                 /*
 181                  * ACK and CTS are 10 bytes, all others 16. To see how
 182                  * to get this condition consider
 183                  *   subtype mask:   0b0000000011110000 (0x00F0)
 184                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 185                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 186                  *   bits that matter:         ^^^      (0x00E0)
 187                  *   value of those: 0b0000000011000000 (0x00C0)
 188                  */
 189                 if ((fc & 0xE0) == 0xC0)
 190                         hdrlen = 10;
 191                 else
 192                         hdrlen = 16;
 193                 break;
 194         }
 195
 196         return hdrlen;
 197 }
 198 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 199
 200 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 201 {
 202         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 203         int hdrlen;
 204
 205         if (unlikely(skb->len < 10))
 206                 return 0;
 207         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 208         if (unlikely(hdrlen > skb->len))
 209                 return 0;
 210         return hdrlen;
 211 }
 212 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 213
 214 int ieee80211_is_eapol(const struct sk_buff *skb)
 215 {
 216         const struct ieee80211_hdr *hdr;
 217         u16 fc;
 218         int hdrlen;
 219
 220         if (unlikely(skb->len < 10))
 221                 return 0;
 222
 223         hdr = (const struct ieee80211_hdr *) skb->data;
 224         fc = le16_to_cpu(hdr->frame_control);
 225
 226         if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
 227                 return 0;
 228
 229         hdrlen = ieee80211_get_hdrlen(fc);
 230
 231         if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 232                      memcmp(skb->data + hdrlen, eapol_header,
 233                             sizeof(eapol_header)) == 0))
 234                 return 1;
 235
 236         return 0;
 237 }
 238
 239 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 240 {
 241         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 242
 243         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 244         if (tx->u.tx.extra_frag) {
 245                 struct ieee80211_hdr *fhdr;
 246                 int i;
 247                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 248                         fhdr = (struct ieee80211_hdr *)
 249                                 tx->u.tx.extra_frag[i]->data;
 250                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 251                 }
 252         }
 253 }
 254
 255 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 256                              int rate, int erp, int short_preamble)
 257 {
 258         int dur;
 259
 260         /* calculate duration (in microseconds, rounded up to next higher
 261          * integer if it includes a fractional microsecond) to send frame of
 262          * len bytes (does not include FCS) at the given rate. Duration will
 263          * also include SIFS.
 264          *
 265          * rate is in 100 kbps, so divident is multiplied by 10 in the
 266          * DIV_ROUND_UP() operations.
 267          */
 268
 269         if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 270                 /*
 271                  * OFDM:
 272                  *
 273                  * N_DBPS = DATARATE x 4
 274                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 275                  *      (16 = SIGNAL time, 6 = tail bits)
 276                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 277                  *
 278                  * T_SYM = 4 usec
 279                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 280                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 281                  *      signal ext = 6 usec
 282                  */
 283                 dur = 16; /* SIFS + signal ext */
 284                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 285                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 286                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 287                                         4 * rate); /* T_SYM x N_SYM */
 288         } else {
 289                 /*
 290                  * 802.11b or 802.11g with 802.11b compatibility:
 291                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 292                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 293                  *
 294                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 295                  * aSIFSTime = 10 usec
 296                  * aPreambleLength = 144 usec or 72 usec with short preamble
 297                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 298                  */
 299                 dur = 10; /* aSIFSTime = 10 usec */
 300                 dur += short_preamble ? (72 + 24) : (144 + 48);
 301
 302                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 303         }
 304
 305         return dur;
 306 }
 307
 308 /* Exported duration function for driver use */
 309 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 310                                         size_t frame_len, int rate)
 311 {
 312         struct ieee80211_local *local = hw_to_local(hw);
 313         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 314         struct ieee80211_sub_if_data *sdata;
 315         u16 dur;
 316         int erp;
 317
 318         if (unlikely(!bdev))
 319                 return 0;
 320
 321         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 322         erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 323         dur = ieee80211_frame_duration(local, frame_len, rate,
 324                        erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 325
 326         dev_put(bdev);
 327         return cpu_to_le16(dur);
 328 }
 329 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 330
 331 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 332                               size_t frame_len,
 333                               const struct ieee80211_tx_control *frame_txctl)
 334 {
 335         struct ieee80211_local *local = hw_to_local(hw);
 336         struct ieee80211_rate *rate;
 337         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 338         struct ieee80211_sub_if_data *sdata;
 339         int short_preamble;
 340         int erp;
 341         u16 dur;
 342
 343         if (unlikely(!bdev))
 344                 return 0;
 345
 346         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 347         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 348
 349         rate = frame_txctl->rts_rate;
 350         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 351
 352         /* CTS duration */
 353         dur = ieee80211_frame_duration(local, 10, rate->rate,
 354                                        erp, short_preamble);
 355         /* Data frame duration */
 356         dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 357                                         erp, short_preamble);
 358         /* ACK duration */
 359         dur += ieee80211_frame_duration(local, 10, rate->rate,
 360                                         erp, short_preamble);
 361
 362         dev_put(bdev);
 363         return cpu_to_le16(dur);
 364 }
 365 EXPORT_SYMBOL(ieee80211_rts_duration);
 366
 367 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 368                                     size_t frame_len,
 369                                     const struct ieee80211_tx_control *frame_txctl)
 370 {
 371         struct ieee80211_local *local = hw_to_local(hw);
 372         struct ieee80211_rate *rate;
 373         struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 374         struct ieee80211_sub_if_data *sdata;
 375         int short_preamble;
 376         int erp;
 377         u16 dur;
 378
 379         if (unlikely(!bdev))
 380                 return 0;
 381
 382         sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 383         short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 384
 385         rate = frame_txctl->rts_rate;
 386         erp = !!(rate->flags & IEEE80211_RATE_ERP);
 387
 388         /* Data frame duration */
 389         dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 390                                        erp, short_preamble);
 391         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 392                 /* ACK duration */
 393                 dur += ieee80211_frame_duration(local, 10, rate->rate,
 394                                                 erp, short_preamble);
 395         }
 396
 397         dev_put(bdev);
 398         return cpu_to_le16(dur);
 399 }
 400 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 401
 402 struct ieee80211_rate *
 403 ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 404 {
 405         struct ieee80211_hw_mode *mode;
 406         int r;
 407
 408         list_for_each_entry(mode, &local->modes_list, list) {
 409                 if (mode->mode != phymode)
 410                         continue;
 411                 for (r = 0; r < mode->num_rates; r++) {
 412                         struct ieee80211_rate *rate = &mode->rates[r];
 413                         if (rate->val == hw_rate ||
 414                             (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 415                              rate->val2 == hw_rate))
 416                                 return rate;
 417                 }
 418         }
 419
 420         return NULL;
 421 }
 422
 423 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 424 {
 425         struct ieee80211_local *local = hw_to_local(hw);
 426
 427         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 428                                &local->state[queue])) {
 429                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 430                              &local->state[queue]))
 431                         tasklet_schedule(&local->tx_pending_tasklet);
 432                 else
 433                         if (!ieee80211_qdisc_installed(local->mdev)) {
 434                                 if (queue == 0)
 435                                         netif_wake_queue(local->mdev);
 436                         } else
 437                                 __netif_schedule(local->mdev);
 438         }
 439 }
 440 EXPORT_SYMBOL(ieee80211_wake_queue);
 441
 442 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 443 {
 444         struct ieee80211_local *local = hw_to_local(hw);
 445
 446         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 447                 netif_stop_queue(local->mdev);
 448         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 449 }
 450 EXPORT_SYMBOL(ieee80211_stop_queue);
 451
 452 void ieee80211_start_queues(struct ieee80211_hw *hw)
 453 {
 454         struct ieee80211_local *local = hw_to_local(hw);
 455         int i;
 456
 457         for (i = 0; i < local->hw.queues; i++)
 458                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 459         if (!ieee80211_qdisc_installed(local->mdev))
 460                 netif_start_queue(local->mdev);
 461 }
 462 EXPORT_SYMBOL(ieee80211_start_queues);
 463
 464 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 465 {
 466         int i;
 467
 468         for (i = 0; i < hw->queues; i++)
 469                 ieee80211_stop_queue(hw, i);
 470 }
 471 EXPORT_SYMBOL(ieee80211_stop_queues);
 472
 473 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 474 {
 475         int i;
 476
 477         for (i = 0; i < hw->queues; i++)
 478                 ieee80211_wake_queue(hw, i);
 479 }
 480 EXPORT_SYMBOL(ieee80211_wake_queues);