sys/netproto/802_11/ieee80211_phy.h

   1 /*-
   2  * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * $FreeBSD$
  26  */
  27
  28 #ifndef _NET80211_IEEE80211_PHY_H_
  29 #define _NET80211_IEEE80211_PHY_H_
  30
  31 #ifdef _KERNEL
  32 /*
  33  * IEEE 802.11 PHY-related definitions.
  34  */
  35
  36 /*
  37  * Contention window (slots).
  38  */
  39 #define IEEE80211_CW_MAX        1023    /* aCWmax */
  40 #define IEEE80211_CW_MIN_0      31      /* DS/CCK aCWmin, ERP aCWmin(0) */
  41 #define IEEE80211_CW_MIN_1      15      /* OFDM aCWmin, ERP aCWmin(1) */
  42
  43 /*
  44  * SIFS (microseconds).
  45  */
  46 #define IEEE80211_DUR_SIFS      10      /* DS/CCK/ERP SIFS */
  47 #define IEEE80211_DUR_OFDM_SIFS 16      /* OFDM SIFS */
  48
  49 /*
  50  * Slot time (microseconds).
  51  */
  52 #define IEEE80211_DUR_SLOT      20      /* DS/CCK slottime, ERP long slottime */
  53 #define IEEE80211_DUR_SHSLOT    9       /* ERP short slottime */
  54 #define IEEE80211_DUR_OFDM_SLOT 9       /* OFDM slottime */
  55
  56 /*
  57  * DIFS (microseconds).
  58  */
  59 #define IEEE80211_DUR_DIFS(sifs, slot)  ((sifs) + 2 * (slot))
  60
  61 struct ieee80211_channel;
  62
  63 #define IEEE80211_RATE_TABLE_SIZE       128
  64
  65 struct ieee80211_rate_table {
  66         int             rateCount;              /* NB: for proper padding */
  67         uint8_t         rateCodeToIndex[256];   /* back mapping */
  68         struct {
  69                 uint8_t         phy;            /* CCK/OFDM/TURBO */
  70                 uint32_t        rateKbps;       /* transfer rate in kbs */
  71                 uint8_t         shortPreamble;  /* mask for enabling short
  72                                                  * preamble in CCK rate code */
  73                 uint8_t         dot11Rate;      /* value for supported rates
  74                                                  * info element of MLME */
  75                 uint8_t         ctlRateIndex;   /* index of next lower basic
  76                                                  * rate; used for dur. calcs */
  77                 uint16_t        lpAckDuration;  /* long preamble ACK dur. */
  78                 uint16_t        spAckDuration;  /* short preamble ACK dur. */
  79         } info[IEEE80211_RATE_TABLE_SIZE];
  80 };
  81
  82 const struct ieee80211_rate_table *ieee80211_get_ratetable(
  83                         struct ieee80211_channel *);
  84
  85 static __inline__ uint8_t
  86 ieee80211_ack_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
  87 {
  88         /*
  89          * XXX Assert this is for a legacy rate; not for an MCS rate.
  90          * If the caller wishes to use it for a basic rate, they should
  91          * clear the high bit first.
  92          */
  93         KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
  94
  95         uint8_t cix = rt->info[rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]].ctlRateIndex;
  96         KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
  97         return rt->info[cix].dot11Rate;
  98 }
  99
 100 static __inline__ uint8_t
 101 ieee80211_ctl_rate(const struct ieee80211_rate_table *rt, uint8_t rate)
 102 {
 103         /*
 104          * XXX Assert this is for a legacy rate; not for an MCS rate.
 105          * If the caller wishes to use it for a basic rate, they should
 106          * clear the high bit first.
 107          */
 108         KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
 109
 110         uint8_t cix = rt->info[rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]].ctlRateIndex;
 111         KASSERT(cix != (uint8_t)-1, ("rate %d has no info", rate));
 112         return rt->info[cix].dot11Rate;
 113 }
 114
 115 static __inline__ enum ieee80211_phytype
 116 ieee80211_rate2phytype(const struct ieee80211_rate_table *rt, uint8_t rate)
 117 {
 118         /*
 119          * XXX Assert this is for a legacy rate; not for an MCS rate.
 120          * If the caller wishes to use it for a basic rate, they should
 121          * clear the high bit first.
 122          */
 123         KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
 124
 125         uint8_t rix = rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL];
 126         KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate));
 127         return rt->info[rix].phy;
 128 }
 129
 130 static __inline__ int
 131 ieee80211_isratevalid(const struct ieee80211_rate_table *rt, uint8_t rate)
 132 {
 133         /*
 134          * XXX Assert this is for a legacy rate; not for an MCS rate.
 135          * If the caller wishes to use it for a basic rate, they should
 136          * clear the high bit first.
 137          */
 138         KASSERT(! (rate & 0x80), ("rate %d is basic/mcs?", rate));
 139
 140         return rt->rateCodeToIndex[rate] != (uint8_t)-1;
 141 }
 142
 143 /*
 144  * Calculate ACK field for
 145  * o  non-fragment data frames
 146  * o  management frames
 147  * sent using rate, phy and short preamble setting.
 148  */
 149 static __inline__ uint16_t
 150 ieee80211_ack_duration(const struct ieee80211_rate_table *rt,
 151     uint8_t rate, int isShortPreamble)
 152 {
 153         uint8_t rix = rt->rateCodeToIndex[rate];
 154
 155         KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate));
 156         if (isShortPreamble) {
 157                 KASSERT(rt->info[rix].spAckDuration != 0,
 158                         ("shpreamble ack dur is not computed!\n"));
 159                 return rt->info[rix].spAckDuration;
 160         } else {
 161                 KASSERT(rt->info[rix].lpAckDuration != 0,
 162                         ("lgpreamble ack dur is not computed!\n"));
 163                 return rt->info[rix].lpAckDuration;
 164         }
 165 }
 166
 167 static __inline__ uint8_t
 168 ieee80211_legacy_rate_lookup(const struct ieee80211_rate_table *rt,
 169     uint8_t rate)
 170 {
 171
 172         return (rt->rateCodeToIndex[rate & IEEE80211_RATE_VAL]);
 173 }
 174
 175 /*
 176  * Compute the time to transmit a frame of length frameLen bytes
 177  * using the specified 802.11 rate code, phy, and short preamble
 178  * setting.
 179  *
 180  * NB: SIFS is included.
 181  */
 182 uint16_t        ieee80211_compute_duration(const struct ieee80211_rate_table *,
 183                         uint32_t frameLen, uint16_t rate, int isShortPreamble);
 184 /*
 185  * Convert PLCP signal/rate field to 802.11 rate code (.5Mbits/s)
 186  */
 187 uint8_t         ieee80211_plcp2rate(uint8_t, enum ieee80211_phytype);
 188 /*
 189  * Convert 802.11 rate code to PLCP signal.
 190  */
 191 uint8_t         ieee80211_rate2plcp(int, enum ieee80211_phytype);
 192
 193 uint32_t        ieee80211_compute_duration_ht(uint32_t frameLen,
 194                         uint16_t rate, int streams, int isht40,
 195                         int isShortGI);
 196
 197 #endif  /* _KERNEL */
 198 #endif  /* !_NET80211_IEEE80211_PHY_H_ */