LXR linux/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 */
  31void *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) */
  35const 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) */
  39const unsigned char bridge_tunnel_header[] =
  40        { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
  41
  42/* No encapsulation header if EtherType < 0x600 (=length) */
  43static const unsigned char eapol_header[] =
  44        { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00, 0x88, 0x8e };
  45
  46
  47static 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
  61void 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                case NUM_IEEE80211_MODES:
 102                        /* not useful */
 103                        break;
 104                }
 105
 106                /* Set ERP and MANDATORY flags based on phymode */
 107                switch (mode->mode) {
 108                case MODE_IEEE80211A:
 109                        if (rate->rate == 60 || rate->rate == 120 ||
 110                            rate->rate == 240)
 111                                rate->flags |= IEEE80211_RATE_MANDATORY;
 112                        break;
 113                case MODE_IEEE80211B:
 114                        if (rate->rate == 10)
 115                                rate->flags |= IEEE80211_RATE_MANDATORY;
 116                        break;
 117                case MODE_IEEE80211G:
 118                        if (rate->rate == 10 || rate->rate == 20 ||
 119                            rate->rate == 55 || rate->rate == 110 ||
 120                            rate->rate == 60 || rate->rate == 120 ||
 121                            rate->rate == 240)
 122                                rate->flags |= IEEE80211_RATE_MANDATORY;
 123                        break;
 124                case NUM_IEEE80211_MODES:
 125                        /* not useful */
 126                        break;
 127                }
 128                if (ieee80211_is_erp_rate(mode->mode, rate->rate))
 129                        rate->flags |= IEEE80211_RATE_ERP;
 130        }
 131}
 132
 133u8 *ieee80211_get_bssid(struct ieee80211_hdr *hdr, size_t len)
 134{
 135        u16 fc;
 136
 137        if (len < 24)
 138                return NULL;
 139
 140        fc = le16_to_cpu(hdr->frame_control);
 141
 142        switch (fc & IEEE80211_FCTL_FTYPE) {
 143        case IEEE80211_FTYPE_DATA:
 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                return hdr->addr3;
 157        case IEEE80211_FTYPE_CTL:
 158                if ((fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_PSPOLL)
 159                        return hdr->addr1;
 160                else
 161                        return NULL;
 162        }
 163
 164        return NULL;
 165}
 166
 167int ieee80211_get_hdrlen(u16 fc)
 168{
 169        int hdrlen = 24;
 170
 171        switch (fc & IEEE80211_FCTL_FTYPE) {
 172        case IEEE80211_FTYPE_DATA:
 173                if ((fc & IEEE80211_FCTL_FROMDS) && (fc & IEEE80211_FCTL_TODS))
 174                        hdrlen = 30; /* Addr4 */
 175                /*
 176                 * The QoS Control field is two bytes and its presence is
 177                 * indicated by the IEEE80211_STYPE_QOS_DATA bit. Add 2 to
 178                 * hdrlen if that bit is set.
 179                 * This works by masking out the bit and shifting it to
 180                 * bit position 1 so the result has the value 0 or 2.
 181                 */
 182                hdrlen += (fc & IEEE80211_STYPE_QOS_DATA)
 183                                >> (ilog2(IEEE80211_STYPE_QOS_DATA)-1);
 184                break;
 185        case IEEE80211_FTYPE_CTL:
 186                /*
 187                 * ACK and CTS are 10 bytes, all others 16. To see how
 188                 * to get this condition consider
 189                 *   subtype mask:   0b0000000011110000 (0x00F0)
 190                 *   ACK subtype:    0b0000000011010000 (0x00D0)
 191                 *   CTS subtype:    0b0000000011000000 (0x00C0)
 192                 *   bits that matter:         ^^^      (0x00E0)
 193                 *   value of those: 0b0000000011000000 (0x00C0)
 194                 */
 195                if ((fc & 0xE0) == 0xC0)
 196                        hdrlen = 10;
 197                else
 198                        hdrlen = 16;
 199                break;
 200        }
 201
 202        return hdrlen;
 203}
 204EXPORT_SYMBOL(ieee80211_get_hdrlen);
 205
 206int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 207{
 208        const struct ieee80211_hdr *hdr = (const struct ieee80211_hdr *) skb->data;
 209        int hdrlen;
 210
 211        if (unlikely(skb->len < 10))
 212                return 0;
 213        hdrlen = ieee80211_get_hdrlen(le16_to_cpu(hdr->frame_control));
 214        if (unlikely(hdrlen > skb->len))
 215                return 0;
 216        return hdrlen;
 217}
 218EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 219
 220int ieee80211_is_eapol(const struct sk_buff *skb)
 221{
 222        const struct ieee80211_hdr *hdr;
 223        u16 fc;
 224        int hdrlen;
 225
 226        if (unlikely(skb->len < 10))
 227                return 0;
 228
 229        hdr = (const struct ieee80211_hdr *) skb->data;
 230        fc = le16_to_cpu(hdr->frame_control);
 231
 232        if (unlikely(!WLAN_FC_DATA_PRESENT(fc)))
 233                return 0;
 234
 235        hdrlen = ieee80211_get_hdrlen(fc);
 236
 237        if (unlikely(skb->len >= hdrlen + sizeof(eapol_header) &&
 238                     memcmp(skb->data + hdrlen, eapol_header,
 239                            sizeof(eapol_header)) == 0))
 240                return 1;
 241
 242        return 0;
 243}
 244
 245void ieee80211_tx_set_iswep(struct ieee80211_txrx_data *tx)
 246{
 247        struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) tx->skb->data;
 248
 249        hdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 250        if (tx->u.tx.extra_frag) {
 251                struct ieee80211_hdr *fhdr;
 252                int i;
 253                for (i = 0; i < tx->u.tx.num_extra_frag; i++) {
 254                        fhdr = (struct ieee80211_hdr *)
 255                                tx->u.tx.extra_frag[i]->data;
 256                        fhdr->frame_control |= cpu_to_le16(IEEE80211_FCTL_PROTECTED);
 257                }
 258        }
 259}
 260
 261int ieee80211_frame_duration(struct ieee80211_local *local, size_t len,
 262                             int rate, int erp, int short_preamble)
 263{
 264        int dur;
 265
 266        /* calculate duration (in microseconds, rounded up to next higher
 267         * integer if it includes a fractional microsecond) to send frame of
 268         * len bytes (does not include FCS) at the given rate. Duration will
 269         * also include SIFS.
 270         *
 271         * rate is in 100 kbps, so divident is multiplied by 10 in the
 272         * DIV_ROUND_UP() operations.
 273         */
 274
 275        if (local->hw.conf.phymode == MODE_IEEE80211A || erp) {
 276                /*
 277                 * OFDM:
 278                 *
 279                 * N_DBPS = DATARATE x 4
 280                 * N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
 281                 *      (16 = SIGNAL time, 6 = tail bits)
 282                 * TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
 283                 *
 284                 * T_SYM = 4 usec
 285                 * 802.11a - 17.5.2: aSIFSTime = 16 usec
 286                 * 802.11g - 19.8.4: aSIFSTime = 10 usec +
 287                 *      signal ext = 6 usec
 288                 */
 289                dur = 16; /* SIFS + signal ext */
 290                dur += 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
 291                dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
 292                dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
 293                                        4 * rate); /* T_SYM x N_SYM */
 294        } else {
 295                /*
 296                 * 802.11b or 802.11g with 802.11b compatibility:
 297                 * 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
 298                 * Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
 299                 *
 300                 * 802.11 (DS): 15.3.3, 802.11b: 18.3.4
 301                 * aSIFSTime = 10 usec
 302                 * aPreambleLength = 144 usec or 72 usec with short preamble
 303                 * aPLCPHeaderLength = 48 usec or 24 usec with short preamble
 304                 */
 305                dur = 10; /* aSIFSTime = 10 usec */
 306                dur += short_preamble ? (72 + 24) : (144 + 48);
 307
 308                dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
 309        }
 310
 311        return dur;
 312}
 313
 314/* Exported duration function for driver use */
 315__le16 ieee80211_generic_frame_duration(struct ieee80211_hw *hw, int if_id,
 316                                        size_t frame_len, int rate)
 317{
 318        struct ieee80211_local *local = hw_to_local(hw);
 319        struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 320        struct ieee80211_sub_if_data *sdata;
 321        u16 dur;
 322        int erp;
 323
 324        if (unlikely(!bdev))
 325                return 0;
 326
 327        sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 328        erp = ieee80211_is_erp_rate(hw->conf.phymode, rate);
 329        dur = ieee80211_frame_duration(local, frame_len, rate,
 330                       erp, sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE);
 331
 332        dev_put(bdev);
 333        return cpu_to_le16(dur);
 334}
 335EXPORT_SYMBOL(ieee80211_generic_frame_duration);
 336
 337__le16 ieee80211_rts_duration(struct ieee80211_hw *hw, int if_id,
 338                              size_t frame_len,
 339                              const struct ieee80211_tx_control *frame_txctl)
 340{
 341        struct ieee80211_local *local = hw_to_local(hw);
 342        struct ieee80211_rate *rate;
 343        struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 344        struct ieee80211_sub_if_data *sdata;
 345        int short_preamble;
 346        int erp;
 347        u16 dur;
 348
 349        if (unlikely(!bdev))
 350                return 0;
 351
 352        sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 353        short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 354
 355        rate = frame_txctl->rts_rate;
 356        erp = !!(rate->flags & IEEE80211_RATE_ERP);
 357
 358        /* CTS duration */
 359        dur = ieee80211_frame_duration(local, 10, rate->rate,
 360                                       erp, short_preamble);
 361        /* Data frame duration */
 362        dur += ieee80211_frame_duration(local, frame_len, rate->rate,
 363                                        erp, short_preamble);
 364        /* ACK duration */
 365        dur += ieee80211_frame_duration(local, 10, rate->rate,
 366                                        erp, short_preamble);
 367
 368        dev_put(bdev);
 369        return cpu_to_le16(dur);
 370}
 371EXPORT_SYMBOL(ieee80211_rts_duration);
 372
 373__le16 ieee80211_ctstoself_duration(struct ieee80211_hw *hw, int if_id,
 374                                    size_t frame_len,
 375                                    const struct ieee80211_tx_control *frame_txctl)
 376{
 377        struct ieee80211_local *local = hw_to_local(hw);
 378        struct ieee80211_rate *rate;
 379        struct net_device *bdev = dev_get_by_index(&init_net, if_id);
 380        struct ieee80211_sub_if_data *sdata;
 381        int short_preamble;
 382        int erp;
 383        u16 dur;
 384
 385        if (unlikely(!bdev))
 386                return 0;
 387
 388        sdata = IEEE80211_DEV_TO_SUB_IF(bdev);
 389        short_preamble = sdata->flags & IEEE80211_SDATA_SHORT_PREAMBLE;
 390
 391        rate = frame_txctl->rts_rate;
 392        erp = !!(rate->flags & IEEE80211_RATE_ERP);
 393
 394        /* Data frame duration */
 395        dur = ieee80211_frame_duration(local, frame_len, rate->rate,
 396                                       erp, short_preamble);
 397        if (!(frame_txctl->flags & IEEE80211_TXCTL_NO_ACK)) {
 398                /* ACK duration */
 399                dur += ieee80211_frame_duration(local, 10, rate->rate,
 400                                                erp, short_preamble);
 401        }
 402
 403        dev_put(bdev);
 404        return cpu_to_le16(dur);
 405}
 406EXPORT_SYMBOL(ieee80211_ctstoself_duration);
 407
 408struct ieee80211_rate *
 409ieee80211_get_rate(struct ieee80211_local *local, int phymode, int hw_rate)
 410{
 411        struct ieee80211_hw_mode *mode;
 412        int r;
 413
 414        list_for_each_entry(mode, &local->modes_list, list) {
 415                if (mode->mode != phymode)
 416                        continue;
 417                for (r = 0; r < mode->num_rates; r++) {
 418                        struct ieee80211_rate *rate = &mode->rates[r];
 419                        if (rate->val == hw_rate ||
 420                            (rate->flags & IEEE80211_RATE_PREAMBLE2 &&
 421                             rate->val2 == hw_rate))
 422                                return rate;
 423                }
 424        }
 425
 426        return NULL;
 427}
 428
 429void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
 430{
 431        struct ieee80211_local *local = hw_to_local(hw);
 432
 433        if (test_and_clear_bit(IEEE80211_LINK_STATE_XOFF,
 434                               &local->state[queue])) {
 435                if (test_bit(IEEE80211_LINK_STATE_PENDING,
 436                             &local->state[queue]))
 437                        tasklet_schedule(&local->tx_pending_tasklet);
 438                else
 439                        if (!ieee80211_qdisc_installed(local->mdev)) {
 440                                if (queue == 0)
 441                                        netif_wake_queue(local->mdev);
 442                        } else
 443                                __netif_schedule(local->mdev);
 444        }
 445}
 446EXPORT_SYMBOL(ieee80211_wake_queue);
 447
 448void ieee80211_stop_queue(struct ieee80211_hw *hw, int queue)
 449{
 450        struct ieee80211_local *local = hw_to_local(hw);
 451
 452        if (!ieee80211_qdisc_installed(local->mdev) && queue == 0)
 453                netif_stop_queue(local->mdev);
 454        set_bit(IEEE80211_LINK_STATE_XOFF, &local->state[queue]);
 455}
 456EXPORT_SYMBOL(ieee80211_stop_queue);
 457
 458void ieee80211_start_queues(struct ieee80211_hw *hw)
 459{
 460        struct ieee80211_local *local = hw_to_local(hw);
 461        int i;
 462
 463        for (i = 0; i < local->hw.queues; i++)
 464                clear_bit(IEEE80211_LINK_STATE_XOFF, &local->state[i]);
 465        if (!ieee80211_qdisc_installed(local->mdev))
 466                netif_start_queue(local->mdev);
 467}
 468EXPORT_SYMBOL(ieee80211_start_queues);
 469
 470void ieee80211_stop_queues(struct ieee80211_hw *hw)
 471{
 472        int i;
 473
 474        for (i = 0; i < hw->queues; i++)
 475                ieee80211_stop_queue(hw, i);
 476}
 477EXPORT_SYMBOL(ieee80211_stop_queues);
 478
 479void ieee80211_wake_queues(struct ieee80211_hw *hw)
 480{
 481        int i;
 482
 483        for (i = 0; i < hw->queues; i++)
 484                ieee80211_wake_queue(hw, i);
 485}
 486EXPORT_SYMBOL(ieee80211_wake_queues);
 487