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 u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len,
  45                         enum ieee80211_if_types type)
  46 {
  47         u16 fc;
  48
  49          /* drop ACK/CTS frames and incorrect hdr len (ctrl) */
  50         if (len < 16)
  51                 return NULL;
  52
  53         fc = le16_to_cpu(hdr->frame_control);
  54
  55         switch (fc & IEEE80211_FCTL_FTYPE) {
  56         case IEEE80211_FTYPE_DATA:
  57                 if (len < 24) /* drop incorrect hdr len (data) */
  58                         return NULL;
  59                 switch (fc & (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
  60                 case IEEE80211_FCTL_TODS:
  61                         return hdr->addr1;
  62                 case (IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
  63                         return NULL;
  64                 case IEEE80211_FCTL_FROMDS:
  65                         return hdr->addr2;
  66                 case 0:
  67                         return hdr->addr3;
  68                 }
  69                 break;
  70         case IEEE80211_FTYPE_MGMT:
  71                 if (len < 24) /* drop incorrect hdr len (mgmt) */
  72                         return NULL;
  73                 return hdr->addr3;
  74         case IEEE80211_FTYPE_CTL:
  75                 if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
  76                         return hdr->addr1;
  77                 else if ((fc & IEEE80211_FCTL_STYPE) ==
  78                                                 IEEE80211_STYPE_BACK_REQ) {
  79                         switch (type) {
  80                         case IEEE80211_IF_TYPE_STA:
  81                                 return hdr->addr2;
  82                         case IEEE80211_IF_TYPE_AP:
  83                         case IEEE80211_IF_TYPE_VLAN:
  84                                 return hdr->addr1;
  85                         default:
  86                                 return NULL;
  87                         }
  88                 }
  89                 else
  90                         return NULL;
  91         }
  92
  93         return NULL;
  94 }
  95
  96 int ieee80211_get_hdrlen(u16 fc)
  97 {
  98         int hdrlen = 24;
  99
 100         switch (fc & IEEE80211_FCTL_FTYPE) {
 101         case IEEE80211_FTYPE_DATA:
 102                 if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 103                         hdrlen = 30; /* Addr4 */
 104                 /*
 105                  * The QoS Control field is two bytes and its presence is
 106                  * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 107                  * hdrlen if that bit is set.
 108                  * This works by masking out the bit and shifting it to
 109                  * bit position 1 so the result has the value 0 or 2.
 110                  */
 111                 hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 112                                 >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 113                 break;
 114         case IEEE80211_FTYPE_CTL:
 115                 /*
 116                  * ACK and CTS are 10 bytes, all others 16. To see how
 117                  * to get this condition consider
 118                  *   subtype mask:   0b0000000011110000 (0x00F0)
 119                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 120                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 121                  *   bits that matter:         ^^^      (0x00E0)
 122                  *   value of those: 0b0000000011000000 (0x00C0)
 123                  */
 124                 if ((fc & 0xE0) == 0xC0)
 125                         hdrlen = 10;
 126                 else
 127                         hdrlen = 16;
 128                 break;
 129         }
 130
 131         return hdrlen;
 132 }
 133 EXPORT_SYMBOL(ieee80211_get_hdrlen);
 134
 135 int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 136 {
 137         const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 138         int hdrlen;
 139
 140         if (unlikely(skb->len < 10))
 141                 return 0;
 142         hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 143         if (unlikely(hdrlen > skb->len))
 144                 return 0;
 145         return hdrlen;
 146 }
 147 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 148
 149 void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 150 {
 151         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 152
 153         hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 154         if (tx->u.tx.extra_frag) {
 155                 struct ieee80211_hdr *fhdr;
 156                 int i;
 157                 for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 158                         fhdr = (struct ieee80211_hdr *)
 159                                 tx->u.tx.extra_frag[i]->data;
 160                         fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 161                 }
 162         }
 163 }
 164
 165 int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 166                              int rate, int erp, int short_preamble)
 167 {
 168         int dur;
 169
 170         /* calculate duration (in microseconds, rounded up to next higher
 171          * integer if it includes a fractional microsecond) to send frame of
 172          * len bytes (does not include FCS) at the given rate. Duration will
 173          * also include SIFS.
 174          *
 175          * rate is in 100 kbps, so divident is multiplied by 10 in the
 176          * DIV_ROUND_UP() operations.
 177          */
 178
 179         if (local->hw.conf.channel->band == IEEE80211_BAND_5GHZ || erp) {
 180                 /*
 181                  * OFDM:
 182                  *
 183                  * N_DBPS = DATARATE x 4
 184                  * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 185                  *      (16 = SIGNAL time, 6 = tail bits)
 186                  * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 187                  *
 188                  * T_SYM = 4 usec
 189                  * 802.11a - 17.5.2: aSIFSTime = 16 usec
 190                  * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 191                  *      signal ext = 6 usec
 192                  */
 193                 dur = 16; /* SIFS + signal ext */
 194                 dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 195                 dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 196                 dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 197                                         4 * rate); /* T_SYM x N_SYM */
 198         } else {
 199                 /*
 200                  * 802.11b or 802.11g with 802.11b compatibility:
 201                  * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 202                  * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 203                  *
 204                  * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 205                  * aSIFSTime = 10 usec
 206                  * aPreambleLength = 144 usec or 72 usec with short preamble
 207                  * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 208                  */
 209                 dur = 10; /* aSIFSTime = 10 usec */
 210                 dur += short_preamble ? (72 + 24) : (144 + 48);
 211
 212                 dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 213         }
 214
 215         return dur;
 216 }
 217
 218 /* Exported duration function for driver use */
 219 __le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw,
 220                                         struct ieee80211_vif *vif,
 221                                         size_t frame_len,
 222                                         struct ieee80211_rate *rate)
 223 {
 224         struct ieee80211_local *local = hw_to_local(hw);
 225         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 226         u16 dur;
 227         int erp;
 228
 229         erp = 0;
 230         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 231                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 232
 233         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate, erp,
 234                                        sdata->bss_conf.use_short_preamble);
 235
 236         return cpu_to_le16(dur);
 237 }
 238 EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 239
 240 __le16 ieee80211_rts_duration(struct ieee80211_hw *hw,
 241                               struct ieee80211_vif *vif, size_t frame_len,
 242                               const struct ieee80211_tx_control *frame_txctl)
 243 {
 244         struct ieee80211_local *local = hw_to_local(hw);
 245         struct ieee80211_rate *rate;
 246         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 247         bool short_preamble;
 248         int erp;
 249         u16 dur;
 250
 251         short_preamble = sdata->bss_conf.use_short_preamble;
 252
 253         rate = frame_txctl->rts_cts_rate;
 254
 255         erp = 0;
 256         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 257                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 258
 259         /* CTS duration */
 260         dur = ieee80211_frame_duration(local, 10, rate->bitrate,
 261                                        erp, short_preamble);
 262         /* Data frame duration */
 263         dur += ieee80211_frame_duration(local, frame_len, rate->bitrate,
 264                                         erp, short_preamble);
 265         /* ACK duration */
 266         dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 267                                         erp, short_preamble);
 268
 269         return cpu_to_le16(dur);
 270 }
 271 EXPORT_SYMBOL(ieee80211_rts_duration);
 272
 273 __le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw,
 274                                     struct ieee80211_vif *vif,
 275                                     size_t frame_len,
 276                                     const struct ieee80211_tx_control *frame_txctl)
 277 {
 278         struct ieee80211_local *local = hw_to_local(hw);
 279         struct ieee80211_rate *rate;
 280         struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif);
 281         bool short_preamble;
 282         int erp;
 283         u16 dur;
 284
 285         short_preamble = sdata->bss_conf.use_short_preamble;
 286
 287         rate = frame_txctl->rts_cts_rate;
 288         erp = 0;
 289         if (sdata->flags & IEEE80211_SDATA_OPERATING_GMODE)
 290                 erp = rate->flags & IEEE80211_RATE_ERP_G;
 291
 292         /* Data frame duration */
 293         dur = ieee80211_frame_duration(local, frame_len, rate->bitrate,
 294                                        erp, short_preamble);
 295         if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 296                 /* ACK duration */
 297                 dur += ieee80211_frame_duration(local, 10, rate->bitrate,
 298                                                 erp, short_preamble);
 299         }
 300
 301         return cpu_to_le16(dur);
 302 }
 303 EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 304
 305 void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 306 {
 307         struct ieee80211_local *local = hw_to_local(hw);
 308
 309         if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 310                                &local->state[queue])) {
 311                 if (test_bit(IEEE80211_LINK_STATE_PENDING,
 312                              &local->state[queue]))
 313                         tasklet_schedule(&local->tx_pending_tasklet);
 314                 else
 315                         if (!ieee80211_qdisc_installed(local->mdev)) {
 316                                 if (queue == 0)
 317                                         netif_wake_queue(local->mdev);
 318                         } else
 319                                 __netif_schedule(local->mdev);
 320         }
 321 }
 322 EXPORT_SYMBOL(ieee80211_wake_queue);
 323
 324 void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 325 {
 326         struct ieee80211_local *local = hw_to_local(hw);
 327
 328         if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 329                 netif_stop_queue(local->mdev);
 330         set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 331 }
 332 EXPORT_SYMBOL(ieee80211_stop_queue);
 333
 334 void ieee80211_start_queues(struct ieee80211_hw *hw)
 335 {
 336         struct ieee80211_local *local = hw_to_local(hw);
 337         int i;
 338
 339         for (i = 0; i < local->hw.queues; i++)
 340                 clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 341         if (!ieee80211_qdisc_installed(local->mdev))
 342                 netif_start_queue(local->mdev);
 343 }
 344 EXPORT_SYMBOL(ieee80211_start_queues);
 345
 346 void ieee80211_stop_queues(struct ieee80211_hw *hw)
 347 {
 348         int i;
 349
 350         for (i = 0; i < hw->queues; i++)
 351                 ieee80211_stop_queue(hw, i);
 352 }
 353 EXPORT_SYMBOL(ieee80211_stop_queues);
 354
 355 void ieee80211_wake_queues(struct ieee80211_hw *hw)
 356 {
 357         int i;
 358
 359         for (i = 0; i < hw->queues; i++)
 360                 ieee80211_wake_queue(hw, i);
 361 }
 362 EXPORT_SYMBOL(ieee80211_wake_queues);
 363
 364 void ieee80211_iterate_active_interfaces(
 365         struct ieee80211_hw *hw,
 366         void (*iterator)(void *data, u8 *mac,
 367                          struct ieee80211_vif *vif),
 368         void *data)
 369 {
 370         struct ieee80211_local *local = hw_to_local(hw);
 371         struct ieee80211_sub_if_data *sdata;
 372
 373         rcu_read_lock();
 374
 375         list_for_each_entry_rcu(sdata, &local->interfaces, list) {
 376                 switch (sdata->vif.type) {
 377                 case IEEE80211_IF_TYPE_INVALID:
 378                 case IEEE80211_IF_TYPE_MNTR:
 379                 case IEEE80211_IF_TYPE_VLAN:
 380                         continue;
 381                 case IEEE80211_IF_TYPE_AP:
 382                 case IEEE80211_IF_TYPE_STA:
 383                 case IEEE80211_IF_TYPE_IBSS:
 384                 case IEEE80211_IF_TYPE_WDS:
 385                         break;
 386                 }
 387                 if (sdata->dev == local->mdev)
 388                         continue;
 389                 if (netif_running(sdata->dev))
 390                         iterator(data, sdata->dev->dev_addr,
 391                                  &sdata->vif);
 392         }
 393
 394         rcu_read_unlock();
 395 }
 396 EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);