diff options
Diffstat (limited to 'sys/net80211/ieee80211_phy.c')
-rw-r--r-- | sys/net80211/ieee80211_phy.c | 472 |
1 files changed, 472 insertions, 0 deletions
diff --git a/sys/net80211/ieee80211_phy.c b/sys/net80211/ieee80211_phy.c new file mode 100644 index 0000000..e1c847f --- /dev/null +++ b/sys/net80211/ieee80211_phy.c @@ -0,0 +1,472 @@ +/*- + * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR + * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES + * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. + * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +/* + * IEEE 802.11 PHY-related support. + */ + +#include "opt_inet.h" + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/systm.h> + +#include <sys/socket.h> + +#include <net/if.h> +#include <net/if_media.h> + +#include <net80211/ieee80211_var.h> +#include <net80211/ieee80211_phy.h> + +#ifdef notyet +struct ieee80211_ds_plcp_hdr { + uint8_t i_signal; + uint8_t i_service; + uint16_t i_length; + uint16_t i_crc; +} __packed; + +#endif /* notyet */ + +/* shorthands to compact tables for readability */ +#define OFDM IEEE80211_T_OFDM +#define CCK IEEE80211_T_CCK +#define TURBO IEEE80211_T_TURBO +#define PBCC (IEEE80211_T_HT+1) /* XXX */ + +static struct ieee80211_rate_table ieee80211_11b_table = { + 4, /* number of rates, XXX no PBCC */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 1 Mb */ { CCK, 1000, 0x00, (0x80| 2), 0 }, +/* 2 Mb */ { CCK, 2000, 0x04, (0x80| 4), 1 }, +/* 5.5 Mb */ { CCK, 5500, 0x04, (0x80|11), 1 }, +/* 11 Mb */ { CCK, 11000, 0x04, (0x80|22), 1 }, +/* 22 Mb */ { PBCC, 22000, 0x04, 44, 3 } + }, +}; + + +static struct ieee80211_rate_table ieee80211_11g_table = { + 12, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 1 Mb */ { CCK, 1000, 0x00, (0x80| 2), 0 }, +/* 2 Mb */ { CCK, 2000, 0x04, (0x80| 4), 1 }, +/* 5.5 Mb */ { CCK, 5500, 0x04, (0x80|11), 2 }, +/* 11 Mb */ { CCK, 11000, 0x04, (0x80|22), 3 }, +/* 6 Mb */ { OFDM, 6000, 0x00, 12, 4 }, +/* 9 Mb */ { OFDM, 9000, 0x00, 18, 4 }, +/* 12 Mb */ { OFDM, 12000, 0x00, 24, 6 }, +/* 18 Mb */ { OFDM, 18000, 0x00, 36, 6 }, +/* 24 Mb */ { OFDM, 24000, 0x00, 48, 8 }, +/* 36 Mb */ { OFDM, 36000, 0x00, 72, 8 }, +/* 48 Mb */ { OFDM, 48000, 0x00, 96, 8 }, +/* 54 Mb */ { OFDM, 54000, 0x00, 108, 8 } + }, +}; + +static struct ieee80211_rate_table ieee80211_11a_table = { + 8, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 6 Mb */ { OFDM, 6000, 0x00, (0x80|12), 0 }, +/* 9 Mb */ { OFDM, 9000, 0x00, 18, 0 }, +/* 12 Mb */ { OFDM, 12000, 0x00, (0x80|24), 2 }, +/* 18 Mb */ { OFDM, 18000, 0x00, 36, 2 }, +/* 24 Mb */ { OFDM, 24000, 0x00, (0x80|48), 4 }, +/* 36 Mb */ { OFDM, 36000, 0x00, 72, 4 }, +/* 48 Mb */ { OFDM, 48000, 0x00, 96, 4 }, +/* 54 Mb */ { OFDM, 54000, 0x00, 108, 4 } + }, +}; + +static struct ieee80211_rate_table ieee80211_half_table = { + 8, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 6 Mb */ { OFDM, 3000, 0x00, (0x80| 6), 0 }, +/* 9 Mb */ { OFDM, 4500, 0x00, 9, 0 }, +/* 12 Mb */ { OFDM, 6000, 0x00, (0x80|12), 2 }, +/* 18 Mb */ { OFDM, 9000, 0x00, 18, 2 }, +/* 24 Mb */ { OFDM, 12000, 0x00, (0x80|24), 4 }, +/* 36 Mb */ { OFDM, 18000, 0x00, 36, 4 }, +/* 48 Mb */ { OFDM, 24000, 0x00, 48, 4 }, +/* 54 Mb */ { OFDM, 27000, 0x00, 54, 4 } + }, +}; + +static struct ieee80211_rate_table ieee80211_quarter_table = { + 8, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 6 Mb */ { OFDM, 1500, 0x00, (0x80| 3), 0 }, +/* 9 Mb */ { OFDM, 2250, 0x00, 4, 0 }, +/* 12 Mb */ { OFDM, 3000, 0x00, (0x80| 6), 2 }, +/* 18 Mb */ { OFDM, 4500, 0x00, 9, 2 }, +/* 24 Mb */ { OFDM, 6000, 0x00, (0x80|12), 4 }, +/* 36 Mb */ { OFDM, 9000, 0x00, 18, 4 }, +/* 48 Mb */ { OFDM, 12000, 0x00, 24, 4 }, +/* 54 Mb */ { OFDM, 13500, 0x00, 27, 4 } + }, +}; + +static struct ieee80211_rate_table ieee80211_turbog_table = { + 7, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 6 Mb */ { TURBO, 6000, 0x00, (0x80|12), 0 }, +/* 12 Mb */ { TURBO, 12000, 0x00, (0x80|24), 1 }, +/* 18 Mb */ { TURBO, 18000, 0x00, 36, 1 }, +/* 24 Mb */ { TURBO, 24000, 0x00, (0x80|48), 3 }, +/* 36 Mb */ { TURBO, 36000, 0x00, 72, 3 }, +/* 48 Mb */ { TURBO, 48000, 0x00, 96, 3 }, +/* 54 Mb */ { TURBO, 54000, 0x00, 108, 3 } + }, +}; + +static struct ieee80211_rate_table ieee80211_turboa_table = { + 8, /* number of rates */ + { 0 }, + { +/* short ctrl */ +/* Preamble dot11Rate Rate */ +/* 6 Mb */ { TURBO, 6000, 0x00, (0x80|12), 0 }, +/* 9 Mb */ { TURBO, 9000, 0x00, 18, 0 }, +/* 12 Mb */ { TURBO, 12000, 0x00, (0x80|24), 2 }, +/* 18 Mb */ { TURBO, 18000, 0x00, 36, 2 }, +/* 24 Mb */ { TURBO, 24000, 0x00, (0x80|48), 4 }, +/* 36 Mb */ { TURBO, 36000, 0x00, 72, 4 }, +/* 48 Mb */ { TURBO, 48000, 0x00, 96, 4 }, +/* 54 Mb */ { TURBO, 54000, 0x00, 108, 4 } + }, +}; + +#undef OFDM +#undef CCK +#undef TURBO +#undef XR + +/* + * Setup a rate table's reverse lookup table and fill in + * ack durations. The reverse lookup tables are assumed + * to be initialized to zero (or at least the first entry). + * We use this as a key that indicates whether or not + * we've previously setup the reverse lookup table. + * + * XXX not reentrant, but shouldn't matter + */ +static void +ieee80211_setup_ratetable(struct ieee80211_rate_table *rt) +{ +#define N(a) (sizeof(a)/sizeof(a[0])) +#define WLAN_CTRL_FRAME_SIZE \ + (sizeof(struct ieee80211_frame_ack) + IEEE80211_CRC_LEN) + + int i; + + for (i = 0; i < N(rt->rateCodeToIndex); i++) + rt->rateCodeToIndex[i] = (uint8_t) -1; + for (i = 0; i < rt->rateCount; i++) { + uint8_t code = rt->info[i].dot11Rate; + uint8_t cix = rt->info[i].ctlRateIndex; + uint8_t ctl_rate = rt->info[cix].dot11Rate; + + rt->rateCodeToIndex[code] = i; + if (code & IEEE80211_RATE_BASIC) { + /* + * Map w/o basic rate bit too. + */ + code &= IEEE80211_RATE_VAL; + rt->rateCodeToIndex[code] = i; + } + + /* + * XXX for 11g the control rate to use for 5.5 and 11 Mb/s + * depends on whether they are marked as basic rates; + * the static tables are setup with an 11b-compatible + * 2Mb/s rate which will work but is suboptimal + * + * NB: Control rate is always less than or equal to the + * current rate, so control rate's reverse lookup entry + * has been installed and following call is safe. + */ + rt->info[i].lpAckDuration = ieee80211_compute_duration(rt, + WLAN_CTRL_FRAME_SIZE, ctl_rate, 0); + rt->info[i].spAckDuration = ieee80211_compute_duration(rt, + WLAN_CTRL_FRAME_SIZE, ctl_rate, IEEE80211_F_SHPREAMBLE); + } + +#undef WLAN_CTRL_FRAME_SIZE +#undef N +} + +/* Setup all rate tables */ +static void +ieee80211_phy_init(void) +{ +#define N(arr) (int)(sizeof(arr) / sizeof(arr[0])) + static struct ieee80211_rate_table * const ratetables[] = { + &ieee80211_half_table, + &ieee80211_quarter_table, + &ieee80211_11a_table, + &ieee80211_11g_table, + &ieee80211_turbog_table, + &ieee80211_turboa_table, + &ieee80211_turboa_table, + &ieee80211_11a_table, + &ieee80211_11g_table, + &ieee80211_11b_table + }; + int i; + + for (i = 0; i < N(ratetables); ++i) + ieee80211_setup_ratetable(ratetables[i]); + +#undef N +} +SYSINIT(wlan_phy, SI_SUB_DRIVERS, SI_ORDER_FIRST, ieee80211_phy_init, NULL); + +const struct ieee80211_rate_table * +ieee80211_get_ratetable(struct ieee80211_channel *c) +{ + const struct ieee80211_rate_table *rt; + + /* XXX HT */ + if (IEEE80211_IS_CHAN_HALF(c)) + rt = &ieee80211_half_table; + else if (IEEE80211_IS_CHAN_QUARTER(c)) + rt = &ieee80211_quarter_table; + else if (IEEE80211_IS_CHAN_HTA(c)) + rt = &ieee80211_11a_table; /* XXX */ + else if (IEEE80211_IS_CHAN_HTG(c)) + rt = &ieee80211_11g_table; /* XXX */ + else if (IEEE80211_IS_CHAN_108G(c)) + rt = &ieee80211_turbog_table; + else if (IEEE80211_IS_CHAN_ST(c)) + rt = &ieee80211_turboa_table; + else if (IEEE80211_IS_CHAN_TURBO(c)) + rt = &ieee80211_turboa_table; + else if (IEEE80211_IS_CHAN_A(c)) + rt = &ieee80211_11a_table; + else if (IEEE80211_IS_CHAN_ANYG(c)) + rt = &ieee80211_11g_table; + else if (IEEE80211_IS_CHAN_B(c)) + rt = &ieee80211_11b_table; + else { + /* NB: should not get here */ + panic("%s: no rate table for channel; freq %u flags 0x%x\n", + __func__, c->ic_freq, c->ic_flags); + } + return rt; +} + +/* + * Convert PLCP signal/rate field to 802.11 rate (.5Mbits/s) + * + * Note we do no parameter checking; this routine is mainly + * used to derive an 802.11 rate for constructing radiotap + * header data for rx frames. + * + * XXX might be a candidate for inline + */ +uint8_t +ieee80211_plcp2rate(uint8_t plcp, int ofdm) +{ + if (ofdm) { + static const uint8_t ofdm_plcp2rate[16] = { + [0xb] = 12, + [0xf] = 18, + [0xa] = 24, + [0xe] = 36, + [0x9] = 48, + [0xd] = 72, + [0x8] = 96, + [0xc] = 108 + }; + return ofdm_plcp2rate[plcp & 0xf]; + } else { + static const uint8_t cck_plcp2rate[16] = { + [0xa] = 2, /* 0x0a */ + [0x4] = 4, /* 0x14 */ + [0x7] = 11, /* 0x37 */ + [0xe] = 22, /* 0x6e */ + [0xc] = 44, /* 0xdc , actually PBCC */ + }; + return cck_plcp2rate[plcp & 0xf]; + } +} + +/* + * Covert 802.11 rate to PLCP signal. + */ +uint8_t +ieee80211_rate2plcp(int rate) +{ + switch (rate) { + /* CCK rates (returned values are device-dependent) */ + case 2: return 0x0; + case 4: return 0x1; + case 11: return 0x2; + case 22: return 0x3; + + /* OFDM rates (cf IEEE Std 802.11a-1999, pp. 14 Table 80) */ + case 12: return 0xb; + case 18: return 0xf; + case 24: return 0xa; + case 36: return 0xe; + case 48: return 0x9; + case 72: return 0xd; + case 96: return 0x8; + case 108: return 0xc; + } + return 0xff; /* XXX unsupported/unknown rate */ +} +/* + * Compute the time to transmit a frame of length frameLen bytes + * using the specified rate, phy, and short preamble setting. + * SIFS is included. + */ +uint16_t +ieee80211_compute_duration(const struct ieee80211_rate_table *rt, + uint32_t frameLen, uint16_t rate, int isShortPreamble) +{ + uint8_t rix = rt->rateCodeToIndex[rate]; + uint32_t bitsPerSymbol, numBits, numSymbols, phyTime, txTime; + uint32_t kbps; + + KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate)); + kbps = rt->info[rix].rateKbps; + if (kbps == 0) /* XXX bandaid for channel changes */ + return 0; + + switch (rt->info[rix].phy) { + case IEEE80211_T_CCK: +#define CCK_SIFS_TIME 10 +#define CCK_PREAMBLE_BITS 144 +#define CCK_PLCP_BITS 48 + phyTime = CCK_PREAMBLE_BITS + CCK_PLCP_BITS; + if (isShortPreamble && rt->info[rix].shortPreamble) + phyTime >>= 1; + numBits = frameLen << 3; + txTime = CCK_SIFS_TIME + phyTime + + ((numBits * 1000)/kbps); + break; +#undef CCK_SIFS_TIME +#undef CCK_PREAMBLE_BITS +#undef CCK_PLCP_BITS + + case IEEE80211_T_OFDM: +#define OFDM_SIFS_TIME 16 +#define OFDM_PREAMBLE_TIME 20 +#define OFDM_PLCP_BITS 22 +#define OFDM_SYMBOL_TIME 4 + +#define OFDM_SIFS_TIME_HALF 32 +#define OFDM_PREAMBLE_TIME_HALF 40 +#define OFDM_PLCP_BITS_HALF 22 +#define OFDM_SYMBOL_TIME_HALF 8 + +#define OFDM_SIFS_TIME_QUARTER 64 +#define OFDM_PREAMBLE_TIME_QUARTER 80 +#define OFDM_PLCP_BITS_QUARTER 22 +#define OFDM_SYMBOL_TIME_QUARTER 16 + if (rt == &ieee80211_half_table) { + bitsPerSymbol = (kbps * OFDM_SYMBOL_TIME_QUARTER) / 1000; + KASSERT(bitsPerSymbol != 0, ("1/2 rate bps")); + + numBits = OFDM_PLCP_BITS + (frameLen << 3); + numSymbols = howmany(numBits, bitsPerSymbol); + txTime = OFDM_SIFS_TIME_QUARTER + + OFDM_PREAMBLE_TIME_QUARTER + + (numSymbols * OFDM_SYMBOL_TIME_QUARTER); + } else if (rt == &ieee80211_quarter_table) { + bitsPerSymbol = (kbps * OFDM_SYMBOL_TIME_HALF) / 1000; + KASSERT(bitsPerSymbol != 0, ("1/4 rate bps")); + + numBits = OFDM_PLCP_BITS + (frameLen << 3); + numSymbols = howmany(numBits, bitsPerSymbol); + txTime = OFDM_SIFS_TIME_HALF + + OFDM_PREAMBLE_TIME_HALF + + (numSymbols * OFDM_SYMBOL_TIME_HALF); + } else { /* full rate channel */ + bitsPerSymbol = (kbps * OFDM_SYMBOL_TIME) / 1000; + KASSERT(bitsPerSymbol != 0, ("full rate bps")); + + numBits = OFDM_PLCP_BITS + (frameLen << 3); + numSymbols = howmany(numBits, bitsPerSymbol); + txTime = OFDM_SIFS_TIME + + OFDM_PREAMBLE_TIME + + (numSymbols * OFDM_SYMBOL_TIME); + } + break; + +#undef OFDM_SIFS_TIME +#undef OFDM_PREAMBLE_TIME +#undef OFDM_PLCP_BITS +#undef OFDM_SYMBOL_TIME + + case IEEE80211_T_TURBO: +#define TURBO_SIFS_TIME 8 +#define TURBO_PREAMBLE_TIME 14 +#define TURBO_PLCP_BITS 22 +#define TURBO_SYMBOL_TIME 4 + /* we still save OFDM rates in kbps - so double them */ + bitsPerSymbol = ((kbps << 1) * TURBO_SYMBOL_TIME) / 1000; + KASSERT(bitsPerSymbol != 0, ("turbo bps")); + + numBits = TURBO_PLCP_BITS + (frameLen << 3); + numSymbols = howmany(numBits, bitsPerSymbol); + txTime = TURBO_SIFS_TIME + TURBO_PREAMBLE_TIME + + (numSymbols * TURBO_SYMBOL_TIME); + break; +#undef TURBO_SIFS_TIME +#undef TURBO_PREAMBLE_TIME +#undef TURBO_PLCP_BITS +#undef TURBO_SYMBOL_TIME + + default: + panic("%s: unknown phy %u (rate %u)\n", __func__, + rt->info[rix].phy, rate); + break; + } + return txTime; +} |