void ieee80211_prepare_rates(struct ieee80211_local *local,
struct ieee80211_hw_mode *mode)
{
int i;
for (i = 0; i < mode->num_rates; i++) {
struct ieee80211_rate *rate = &mode->rates[i];
rate->flags &= ~(IEEE80211_RATE_SUPPORTED |
IEEE80211_RATE_BASIC);
if (local->supp_rates[mode->mode]) {
if (!rate_list_match(local->supp_rates[mode->mode],
rate->rate))
continue;
}
rate->flags |= IEEE80211_RATE_SUPPORTED;
/* Use configured basic rate set if it is available. If not,
* use defaults that are sane for most cases. */
if (local->basic_rates[mode->mode]) {
if (rate_list_match(local->basic_rates[mode->mode],
rate->rate))
rate->flags |= IEEE80211_RATE_BASIC;
} else switch (mode->mode) {
case MODE_IEEE80211A:
if (rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_IEEE80211B:
if (rate->rate == 10 || rate->rate == 20)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_ATHEROS_TURBO:
if (rate->rate == 120 || rate->rate == 240 ||
rate->rate == 480)
rate->flags |= IEEE80211_RATE_BASIC;
break;
case MODE_IEEE80211G:
if (rate->rate == 10 || rate->rate == 20 ||
rate->rate == 55 || rate->rate == 110)
rate->flags |= IEEE80211_RATE_BASIC;
break;
}
/* Set ERP and MANDATORY flags based on phymode */
switch (mode->mode) {
case MODE_IEEE80211A:
if (rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
case MODE_IEEE80211B:
if (rate->rate == 10)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
case MODE_ATHEROS_TURBO:
break;
case MODE_IEEE80211G:
if (rate->rate == 10 || rate->rate == 20 ||
rate->rate == 55 || rate->rate == 110 ||
rate->rate == 60 || rate->rate == 120 ||
rate->rate == 240)
rate->flags |= IEEE80211_RATE_MANDATORY;
break;
}
if (ieee80211_is_erp_rate(mode->mode, rate->rate))
rate->flags |= IEEE80211_RATE_ERP;
}
}
/* from mac80211/util.c, modified */
int ieee80211_frame_duration(int phymode, size_t len, int rate, int short_preamble,
int shortslot, int type, char qos_class, int retries)
{
int dur;
bool erp;
int sifs, slottime;
static int last_was_cts;
erp = ieee80211_is_erp_rate(phymode, rate);
/* calculate duration (in microseconds, rounded up to next higher
* integer if it includes a fractional microsecond) to send frame of
* len bytes (does not include FCS) at the given rate. Duration will
* also include SIFS.
*
* rate is in 100 kbps, so divident is multiplied by 10 in the
* DIV_ROUND_UP() operations.
*/
DBG_PRINT("DUR mode %d, len %d, rate %d, shortpre %d shortslot %d type %x UP %d\n", phymode, (int)len, rate, short_preamble, shortslot, type, qos_class);
if (phymode == PHY_FLAG_A || erp) {
DBG_PRINT("OFDM\n");
/*
* OFDM:
*
* N_DBPS = DATARATE x 4
* N_SYM = Ceiling((16+8xLENGTH+6) / N_DBPS)
* (16 = SIGNAL time, 6 = tail bits)
* TXTIME = T_PREAMBLE + T_SIGNAL + T_SYM x N_SYM + Signal Ext
*
* T_SYM = 4 usec
* 802.11a - 17.5.2: aSIFSTime = 16 usec
* 802.11g - 19.8.4: aSIFSTime = 10 usec +
* signal ext = 6 usec
*/
sifs = 16; /* SIFS + signal ext */
slottime = 9;
dur = 16; /* 17.3.2.3: T_PREAMBLE = 16 usec */
dur += 4; /* 17.3.2.3: T_SIGNAL = 4 usec */
dur += 4 * DIV_ROUND_UP((16 + 8 * (len + 4) + 6) * 10,
4 * rate); /* T_SYM x N_SYM */
} else {
DBG_PRINT("CCK\n");
/*
* 802.11b or 802.11g with 802.11b compatibility:
* 18.3.4: TXTIME = PreambleLength + PLCPHeaderTime +
* Ceiling(((LENGTH+PBCC)x8)/DATARATE). PBCC=0.
*
* 802.11 (DS): 15.3.3, 802.11b: 18.3.4
* aSIFSTime = 10 usec
* aPreambleLength = 144 usec or 72 usec with short preamble
* aPLCPHeaderLength = 48 usec or 24 usec with short preamble
*/
sifs = 10; /* aSIFSTime = 10 usec */
slottime = shortslot ? 9 : 20;
dur = short_preamble ? (72 + 24) : (144 + 48);
dur += DIV_ROUND_UP(8 * (len + 4) * 10, rate);
}
if (type == WLAN_FRAME_CTS ||
type == WLAN_FRAME_ACK) {
//TODO: also fragments
DBG_PRINT("DUR SIFS\n");
dur += sifs;
}
else if (type == WLAN_FRAME_BEACON) {
/* TODO: which AIFS and CW should be used for beacons? */
dur += sifs + (2 * slottime); /* AIFS */
dur += (slottime * 1) / 2; /* contention */
}
else if (WLAN_FRAME_IS_DATA(type) && last_was_cts) {
DBG_PRINT("DUR LAST CTS\n");
dur += sifs;
}
else if (type == WLAN_FRAME_QDATA) {
unsigned char ac = ieee802_1d_to_ac[(unsigned char)qos_class];
dur += sifs + (ac_to_aifs[ac] * slottime); /* AIFS */
dur += get_cw_time(ac_to_cwmin[ac], ac_to_cwmax[ac], retries, slottime);
DBG_PRINT("DUR AIFS %d CWMIN %d AC %d, UP %d\n", ac_to_aifs[ac], ac_to_cwmin[ac], ac, qos_class);
}
else {
DBG_PRINT("DUR DIFS\n");
dur += sifs + (2 * slottime); /* DIFS */
dur += get_cw_time(4, 10, retries, slottime);
}
if (type == WLAN_FRAME_CTS) {
DBG_PRINT("SET CTS\n");
last_was_cts = 1;
}
else
last_was_cts = 0;
/* TODO: Add EIFS (SIFS + ACKTXTIME) to frames with CRC errors, if we can get them */
DBG_PRINT("DUR %d\n", dur);
return dur;
}
