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 "rate.h"
  29 #include "mesh.h"
  30 #include "wme.h"
  31
  32 /* privid for wiphys to determine whether they belong to us or not */
  33 void *mac80211_wiphy_privid = &mac80211_wiphy_privid;
  34
  35 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
  36 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
  37 const unsigned char rfc1042_header[] =
  38         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
  39
  40 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
  41 const unsigned char bridge_tunnel_header[] =
  42         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  43
  44
  45 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
  46                         enum ieee80211_if_types type)
  47 {
  48         u16 fc;
  49
  50          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
  51         if (len < 16)
  52                 return NULL;
  53
  54         fc = le16_to_cpu(hdr->frame_control);
  55
  56         switch (fc & IEEE80211_FCTL_FTYPE) {
  57         case IEEE80211_FTYPE_DATA:
  58                 if (len < 24) /* drop incorrect hdr len (data) */
  59                         return NULL;
  60                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
  61                 case IEEE80211_FCTL_TODS:
  62                         return hdr->addr1;
  63                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
  64                         return NULL;
  65                 case IEEE80211_FCTL_FROMDS:
  66                         return hdr->addr2;
  67                 case 0:
  68                         return hdr->addr3;
  69                 }
  70                 break;
  71         case IEEE80211_FTYPE_MGMT:
  72                 if (len < 24) /* drop incorrect hdr len (mgmt) */
  73                         return NULL;
  74                 return hdr->addr3;
  75         case IEEE80211_FTYPE_CTL:
  76                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
  77                         return hdr->addr1;
  78                 else if ((fc & IEEE80211_FCTL_STYPE) ==
  79                                                 IEEE80211_STYPE_BACK_REQ) {
  80                         switch (type) {
  81                         case IEEE80211_IF_TYPE_STA:
  82                                 return hdr->addr2;
  83                         case IEEE80211_IF_TYPE_AP:
  84                         case IEEE80211_IF_TYPE_VLAN:
  85                                 return hdr->addr1;
  86                         default:
  87                                 return NULL;
  88                         }
  89                 }
  90                 else
  91                         return NULL;
  92         }
  93
  94         return NULL;
  95 }
  96
  97 int ieee80211_get_hdrlen(u16 fc)
  98 {
  99         int hdrlen = 24;
 100
 101         switch (fc & IEEE80211_FCTL_FTYPE) {
 102         case IEEE80211_FTYPE_DATA:
 103                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 104                         hdrlen = 30; /* Addr4 */
 105                 /*
 106                  * The QoS Control field is two bytes and its presence is
 107                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 108                  * hdrlen if that bit is set.
 109                  * This works by masking out the bit and shifting it to
 110                  * bit position 1 so the result has the value 0 or 2.
 111                  */
 112                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 113                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 114                 break;
 115         case IEEE80211_FTYPE_CTL:
 116                 /*
 117                  * ACK and CTS are 10 bytes, all others 16. To see how
 118                  * to get this condition consider
 119                  *   subtype mask:   0b0000000011110000 (0x00F0)
 120                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 121                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 122                  *   bits that matter:         ^^^      (0x00E0)
 123                  *   value of those: 0b0000000011000000 (0x00C0)
 124                  */
 125                 if ((fc & 0xE0) == 0xC0)
 126                         hdrlen = 10;
 127                 else
 128                         hdrlen = 16;
 129                 break;
 130         }
 131
 132         return hdrlen;
 133 }
 134 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 135
 136 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 137 {
 138         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 139         int hdrlen;
 140
 141         if (unlikely(skb->len < 10))
 142                 return 0;
 143         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 144         if (unlikely(hdrlen > skb->len))
 145                 return 0;
 146         return hdrlen;
 147 }
 148 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 149
 150 int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 151 {
 152         int ae = meshhdr->flags & IEEE80211S_FLAGS_AE;
 153         /* 7.1.3.5a.2 */
 154         switch (ae) {
 155         case 0:
 156                 return 6;
 157         case 1:
 158                 return 12;
 159         case 2:
 160                 return 18;
 161         case 3:
 162                 return 24;
 163         default:
 164                 return 6;
 165         }
 166 }
 167
 168 void ieee80211_tx_set_protected(struct ieee80211_tx_data *tx)
 169 {
 170         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 171
 172         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 173         if (tx->extra_frag) {
 174                 struct ieee80211_hdr *fhdr;
 175                 int i;
 176                 for (i = 0; i < tx->num_extra_frag; i++) {
 177                         fhdr = (struct ieee80211_hdr *)
 178                                 tx->extra_frag[i]->data;
 179                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 180                 }
 181         }
 182 }
 183
 184 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 185                              int rate, int erp, int short_preamble)
 186 {
 187         int dur;
 188
 189         /* calculate duration (in microseconds, rounded up to next higher
 190          * integer if it includes a fractional microsecond) to send frame of
 191          * len bytes (does not include FCS) at the given rate. Duration will
 192          * also include SIFS.
 193          *
 194          * rate is in 100 kbps, so divident is multiplied by 10 in the
 195          * DIV_ROUND_UP() operations.
 196          */
 197
 198         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
 199                 /*
 200                  * OFDM:
 201                  *
 202                  * N_DBPS = DATARATE x 4
 203                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 204                  *      (16 = SIGNAL time, 6 = tail bits)
 205                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 206                  *
 207                  * T_SYM = 4 usec
 208                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 209                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 210                  *      signal ext = 6 usec
 211                  */
 212                 dur = 16; /* SIFS + signal ext */
 213                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 214                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 215                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 216                                         4 * rate); /* T_SYM x N_SYM */
 217         } else {
 218                 /*
 219                  * 802.11b or 802.11g with 802.11b compatibility:
 220                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 221                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 222                  *
 223                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 224                  * aSIFSTime = 10 usec
 225                  * aPreambleLength = 144 usec or 72 usec with short preamble
 226                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 227                  */
 228                 dur = 10; /* aSIFSTime = 10 usec */
 229                 dur += short_preamble ? (72 + 24) : (144 + 48);
 230
 231                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 232         }
 233
 234         return dur;
 235 }
 236
 237 /* Exported duration function for driver use */
 238 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 239                                         struct ieee80211_vif *vif,
 240                                         size_t frame_len,
 241                                         struct ieee80211_rate *rate)
 242 {
 243         struct ieee80211_local *local = hw_to_local(hw);
 244         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 245         u16 dur;
 246         int erp;
 247
 248         erp = 0;
 249         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 250                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 251
 252         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
 253                                        sdata->bss_conf.use_short_preamble);
 254
 255         return cpu_to_le16(dur);
 256 }
 257 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 258
 259 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 260                               struct ieee80211_vif *vif, size_t frame_len,
 261                               const struct ieee80211_tx_control *frame_txctl)
 262 {
 263         struct ieee80211_local *local = hw_to_local(hw);
 264         struct ieee80211_rate *rate;
 265         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 266         bool short_preamble;
 267         int erp;
 268         u16 dur;
 269
 270         short_preamble = sdata->bss_conf.use_short_preamble;
 271
 272         rate = frame_txctl->rts_cts_rate;
 273
 274         erp = 0;
 275         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 276                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 277
 278         /* CTS duration */
 279         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
 280                                        erp, short_preamble);
 281         /* Data frame duration */
 282         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
 283                                         erp, short_preamble);
 284         /* ACK duration */
 285         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 286                                         erp, short_preamble);
 287
 288         return cpu_to_le16(dur);
 289 }
 290 EXPORT_SYMBOL(ieee80211_rts_duration);
 291
 292 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 293                                     struct ieee80211_vif *vif,
 294                                     size_t frame_len,
 295                                     const struct ieee80211_tx_control *frame_txctl)
 296 {
 297         struct ieee80211_local *local = hw_to_local(hw);
 298         struct ieee80211_rate *rate;
 299         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 300         bool short_preamble;
 301         int erp;
 302         u16 dur;
 303
 304         short_preamble = sdata->bss_conf.use_short_preamble;
 305
 306         rate = frame_txctl->rts_cts_rate;
 307         erp = 0;
 308         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 309                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 310
 311         /* Data frame duration */
 312         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
 313                                        erp, short_preamble);
 314         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 315                 /* ACK duration */
 316                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 317                                                 erp, short_preamble);
 318         }
 319
 320         return cpu_to_le16(dur);
 321 }
 322 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 323
 324 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 325 {
 326         struct ieee80211_local *local = hw_to_local(hw);
 327
 328         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 329                                &local->state[queue])) {
 330                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 331                              &local->state[queue]))
 332                         tasklet_schedule(&local->tx_pending_tasklet);
 333                 else
 334                         if (!ieee80211_qdisc_installed(local->mdev)) {
 335                                 if (queue == 0)
 336                                         netif_wake_queue(local->mdev);
 337                         } else
 338                                 __netif_schedule(local->mdev);
 339         }
 340 }
 341 EXPORT_SYMBOL(ieee80211_wake_queue);
 342
 343 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 344 {
 345         struct ieee80211_local *local = hw_to_local(hw);
 346
 347         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 348                 netif_stop_queue(local->mdev);
 349         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 350 }
 351 EXPORT_SYMBOL(ieee80211_stop_queue);
 352
 353 void ieee80211_start_queues(struct ieee80211_hw *hw)
 354 {
 355         struct ieee80211_local *local = hw_to_local(hw);
 356         int i;
 357
 358         for (i = 0; i < local->hw.queues; i++)
 359                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 360         if (!ieee80211_qdisc_installed(local->mdev))
 361                 netif_start_queue(local->mdev);
 362 }
 363 EXPORT_SYMBOL(ieee80211_start_queues);
 364
 365 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 366 {
 367         int i;
 368
 369         for (i = 0; i < hw->queues; i++)
 370                 ieee80211_stop_queue(hw, i);
 371 }
 372 EXPORT_SYMBOL(ieee80211_stop_queues);
 373
 374 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 375 {
 376         int i;
 377
 378         for (i = 0; i < hw->queues; i++)
 379                 ieee80211_wake_queue(hw, i);
 380 }
 381 EXPORT_SYMBOL(ieee80211_wake_queues);
 382
 383 void ieee80211_iterate_active_interfaces(
 384         struct ieee80211_hw *hw,
 385         void (*iterator)(void *data, u8 *mac,
 386                          struct ieee80211_vif *vif),
 387         void *data)
 388 {
 389         struct ieee80211_local *local = hw_to_local(hw);
 390         struct ieee80211_sub_if_data *sdata;
 391
 392         rcu_read_lock();
 393
 394         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 395                 switch (sdata->vif.type) {
 396                 case IEEE80211_IF_TYPE_INVALID:
 397                 case IEEE80211_IF_TYPE_MNTR:
 398                 case IEEE80211_IF_TYPE_VLAN:
 399                         continue;
 400                 case IEEE80211_IF_TYPE_AP:
 401                 case IEEE80211_IF_TYPE_STA:
 402                 case IEEE80211_IF_TYPE_IBSS:
 403                 case IEEE80211_IF_TYPE_WDS:
 404                 case IEEE80211_IF_TYPE_MESH_POINT:
 405                         break;
 406                 }
 407                 if (sdata->dev == local->mdev)
 408                         continue;
 409                 if (netif_running(sdata->dev))
 410                         iterator(data, sdata->dev->dev_addr,
 411                                  &sdata->vif);
 412         }
 413
 414         rcu_read_unlock();
 415 }
 416 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);