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: head/sys/net80211/ieee80211_phy.c 188821 2009-02-19 17:44:23Z sam $ 26 */ 27 28 /* 29 * IEEE 802.11 PHY-related support. 30 */ 31 32 #include "opt_inet.h" 33 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/systm.h> 37 38 #include <sys/socket.h> 39 40 #include <net/if.h> 41 #include <net/if_media.h> 42 #include <net/route.h> 43 44 #include <netproto/802_11/ieee80211_var.h> 45 #include <netproto/802_11/ieee80211_phy.h> 46 47 #ifdef notyet 48 struct ieee80211_ds_plcp_hdr { 49 uint8_t i_signal; 50 uint8_t i_service; 51 uint16_t i_length; 52 uint16_t i_crc; 53 } __packed; 54 55 #endif /* notyet */ 56 57 /* shorthands to compact tables for readability */ 58 #define OFDM IEEE80211_T_OFDM 59 #define CCK IEEE80211_T_CCK 60 #define TURBO IEEE80211_T_TURBO 61 #define HALF IEEE80211_T_OFDM_HALF 62 #define QUART IEEE80211_T_OFDM_QUARTER 63 #define PBCC (IEEE80211_T_OFDM_QUARTER+1) /* XXX */ 64 #define B(r) (0x80 | r) 65 #define Mb(x) (x*1000) 66 67 static struct ieee80211_rate_table ieee80211_11b_table = { 68 .rateCount = 4, /* XXX no PBCC */ 69 .info = { 70 /* short ctrl */ 71 /* Preamble dot11Rate Rate */ 72 [0] = { .phy = CCK, 1000, 0x00, B(2), 0 },/* 1 Mb */ 73 [1] = { .phy = CCK, 2000, 0x04, B(4), 1 },/* 2 Mb */ 74 [2] = { .phy = CCK, 5500, 0x04, B(11), 1 },/* 5.5 Mb */ 75 [3] = { .phy = CCK, 11000, 0x04, B(22), 1 },/* 11 Mb */ 76 [4] = { .phy = PBCC, 22000, 0x04, 44, 3 } /* 22 Mb */ 77 }, 78 }; 79 80 static struct ieee80211_rate_table ieee80211_11g_table = { 81 .rateCount = 12, 82 .info = { 83 /* short ctrl */ 84 /* Preamble dot11Rate Rate */ 85 [0] = { .phy = CCK, 1000, 0x00, B(2), 0 }, 86 [1] = { .phy = CCK, 2000, 0x04, B(4), 1 }, 87 [2] = { .phy = CCK, 5500, 0x04, B(11), 2 }, 88 [3] = { .phy = CCK, 11000, 0x04, B(22), 3 }, 89 [4] = { .phy = OFDM, 6000, 0x00, 12, 4 }, 90 [5] = { .phy = OFDM, 9000, 0x00, 18, 4 }, 91 [6] = { .phy = OFDM, 12000, 0x00, 24, 6 }, 92 [7] = { .phy = OFDM, 18000, 0x00, 36, 6 }, 93 [8] = { .phy = OFDM, 24000, 0x00, 48, 8 }, 94 [9] = { .phy = OFDM, 36000, 0x00, 72, 8 }, 95 [10] = { .phy = OFDM, 48000, 0x00, 96, 8 }, 96 [11] = { .phy = OFDM, 54000, 0x00, 108, 8 } 97 }, 98 }; 99 100 static struct ieee80211_rate_table ieee80211_11a_table = { 101 .rateCount = 8, 102 .info = { 103 /* short ctrl */ 104 /* Preamble dot11Rate Rate */ 105 [0] = { .phy = OFDM, 6000, 0x00, B(12), 0 }, 106 [1] = { .phy = OFDM, 9000, 0x00, 18, 0 }, 107 [2] = { .phy = OFDM, 12000, 0x00, B(24), 2 }, 108 [3] = { .phy = OFDM, 18000, 0x00, 36, 2 }, 109 [4] = { .phy = OFDM, 24000, 0x00, B(48), 4 }, 110 [5] = { .phy = OFDM, 36000, 0x00, 72, 4 }, 111 [6] = { .phy = OFDM, 48000, 0x00, 96, 4 }, 112 [7] = { .phy = OFDM, 54000, 0x00, 108, 4 } 113 }, 114 }; 115 116 static struct ieee80211_rate_table ieee80211_half_table = { 117 .rateCount = 8, 118 .info = { 119 /* short ctrl */ 120 /* Preamble dot11Rate Rate */ 121 [0] = { .phy = HALF, 3000, 0x00, B(6), 0 }, 122 [1] = { .phy = HALF, 4500, 0x00, 9, 0 }, 123 [2] = { .phy = HALF, 6000, 0x00, B(12), 2 }, 124 [3] = { .phy = HALF, 9000, 0x00, 18, 2 }, 125 [4] = { .phy = HALF, 12000, 0x00, B(24), 4 }, 126 [5] = { .phy = HALF, 18000, 0x00, 36, 4 }, 127 [6] = { .phy = HALF, 24000, 0x00, 48, 4 }, 128 [7] = { .phy = HALF, 27000, 0x00, 54, 4 } 129 }, 130 }; 131 132 static struct ieee80211_rate_table ieee80211_quarter_table = { 133 .rateCount = 8, 134 .info = { 135 /* short ctrl */ 136 /* Preamble dot11Rate Rate */ 137 [0] = { .phy = QUART, 1500, 0x00, B(3), 0 }, 138 [1] = { .phy = QUART, 2250, 0x00, 4, 0 }, 139 [2] = { .phy = QUART, 3000, 0x00, B(9), 2 }, 140 [3] = { .phy = QUART, 4500, 0x00, 9, 2 }, 141 [4] = { .phy = QUART, 6000, 0x00, B(12), 4 }, 142 [5] = { .phy = QUART, 9000, 0x00, 18, 4 }, 143 [6] = { .phy = QUART, 12000, 0x00, 24, 4 }, 144 [7] = { .phy = QUART, 13500, 0x00, 27, 4 } 145 }, 146 }; 147 148 static struct ieee80211_rate_table ieee80211_turbog_table = { 149 .rateCount = 7, 150 .info = { 151 /* short ctrl */ 152 /* Preamble dot11Rate Rate */ 153 [0] = { .phy = TURBO, 12000, 0x00, B(12), 0 }, 154 [1] = { .phy = TURBO, 24000, 0x00, B(24), 1 }, 155 [2] = { .phy = TURBO, 36000, 0x00, 36, 1 }, 156 [3] = { .phy = TURBO, 48000, 0x00, B(48), 3 }, 157 [4] = { .phy = TURBO, 72000, 0x00, 72, 3 }, 158 [5] = { .phy = TURBO, 96000, 0x00, 96, 3 }, 159 [6] = { .phy = TURBO, 108000, 0x00, 108, 3 } 160 }, 161 }; 162 163 static struct ieee80211_rate_table ieee80211_turboa_table = { 164 .rateCount = 8, 165 .info = { 166 /* short ctrl */ 167 /* Preamble dot11Rate Rate */ 168 [0] = { .phy = TURBO, 12000, 0x00, B(12), 0 }, 169 [1] = { .phy = TURBO, 18000, 0x00, 18, 0 }, 170 [2] = { .phy = TURBO, 24000, 0x00, B(24), 2 }, 171 [3] = { .phy = TURBO, 36000, 0x00, 36, 2 }, 172 [4] = { .phy = TURBO, 48000, 0x00, B(48), 4 }, 173 [5] = { .phy = TURBO, 72000, 0x00, 72, 4 }, 174 [6] = { .phy = TURBO, 96000, 0x00, 96, 4 }, 175 [7] = { .phy = TURBO, 108000, 0x00, 108, 4 } 176 }, 177 }; 178 179 #undef Mb 180 #undef B 181 #undef OFDM 182 #undef HALF 183 #undef QUART 184 #undef CCK 185 #undef TURBO 186 #undef XR 187 188 /* 189 * Setup a rate table's reverse lookup table and fill in 190 * ack durations. The reverse lookup tables are assumed 191 * to be initialized to zero (or at least the first entry). 192 * We use this as a key that indicates whether or not 193 * we've previously setup the reverse lookup table. 194 * 195 * XXX not reentrant, but shouldn't matter 196 */ 197 static void 198 ieee80211_setup_ratetable(struct ieee80211_rate_table *rt) 199 { 200 #define WLAN_CTRL_FRAME_SIZE \ 201 (sizeof(struct ieee80211_frame_ack) + IEEE80211_CRC_LEN) 202 203 int i; 204 205 for (i = 0; i < NELEM(rt->rateCodeToIndex); i++) 206 rt->rateCodeToIndex[i] = (uint8_t) -1; 207 for (i = 0; i < rt->rateCount; i++) { 208 uint8_t code = rt->info[i].dot11Rate; 209 uint8_t cix = rt->info[i].ctlRateIndex; 210 uint8_t ctl_rate = rt->info[cix].dot11Rate; 211 212 rt->rateCodeToIndex[code] = i; 213 if (code & IEEE80211_RATE_BASIC) { 214 /* 215 * Map w/o basic rate bit too. 216 */ 217 code &= IEEE80211_RATE_VAL; 218 rt->rateCodeToIndex[code] = i; 219 } 220 221 /* 222 * XXX for 11g the control rate to use for 5.5 and 11 Mb/s 223 * depends on whether they are marked as basic rates; 224 * the static tables are setup with an 11b-compatible 225 * 2Mb/s rate which will work but is suboptimal 226 * 227 * NB: Control rate is always less than or equal to the 228 * current rate, so control rate's reverse lookup entry 229 * has been installed and following call is safe. 230 */ 231 rt->info[i].lpAckDuration = ieee80211_compute_duration(rt, 232 WLAN_CTRL_FRAME_SIZE, ctl_rate, 0); 233 rt->info[i].spAckDuration = ieee80211_compute_duration(rt, 234 WLAN_CTRL_FRAME_SIZE, ctl_rate, IEEE80211_F_SHPREAMBLE); 235 } 236 237 #undef WLAN_CTRL_FRAME_SIZE 238 } 239 240 /* Setup all rate tables */ 241 static void 242 ieee80211_phy_init(void) 243 { 244 static struct ieee80211_rate_table * const ratetables[] = { 245 &ieee80211_half_table, 246 &ieee80211_quarter_table, 247 &ieee80211_11a_table, 248 &ieee80211_11g_table, 249 &ieee80211_turbog_table, 250 &ieee80211_turboa_table, 251 &ieee80211_turboa_table, 252 &ieee80211_11a_table, 253 &ieee80211_11g_table, 254 &ieee80211_11b_table 255 }; 256 int i; 257 258 for (i = 0; i < NELEM(ratetables); ++i) 259 ieee80211_setup_ratetable(ratetables[i]); 260 261 } 262 SYSINIT(wlan_phy, SI_SUB_DRIVERS, SI_ORDER_FIRST, ieee80211_phy_init, NULL); 263 264 const struct ieee80211_rate_table * 265 ieee80211_get_ratetable(struct ieee80211_channel *c) 266 { 267 const struct ieee80211_rate_table *rt; 268 269 /* XXX HT */ 270 if (IEEE80211_IS_CHAN_HALF(c)) 271 rt = &ieee80211_half_table; 272 else if (IEEE80211_IS_CHAN_QUARTER(c)) 273 rt = &ieee80211_quarter_table; 274 else if (IEEE80211_IS_CHAN_HTA(c)) 275 rt = &ieee80211_11a_table; /* XXX */ 276 else if (IEEE80211_IS_CHAN_HTG(c)) 277 rt = &ieee80211_11g_table; /* XXX */ 278 else if (IEEE80211_IS_CHAN_108G(c)) 279 rt = &ieee80211_turbog_table; 280 else if (IEEE80211_IS_CHAN_ST(c)) 281 rt = &ieee80211_turboa_table; 282 else if (IEEE80211_IS_CHAN_TURBO(c)) 283 rt = &ieee80211_turboa_table; 284 else if (IEEE80211_IS_CHAN_A(c)) 285 rt = &ieee80211_11a_table; 286 else if (IEEE80211_IS_CHAN_ANYG(c)) 287 rt = &ieee80211_11g_table; 288 else if (IEEE80211_IS_CHAN_B(c)) 289 rt = &ieee80211_11b_table; 290 else { 291 /* NB: should not get here */ 292 panic("%s: no rate table for channel; freq %u flags 0x%x", 293 __func__, c->ic_freq, c->ic_flags); 294 } 295 return rt; 296 } 297 298 /* 299 * Convert PLCP signal/rate field to 802.11 rate (.5Mbits/s) 300 * 301 * Note we do no parameter checking; this routine is mainly 302 * used to derive an 802.11 rate for constructing radiotap 303 * header data for rx frames. 304 * 305 * XXX might be a candidate for inline 306 */ 307 uint8_t 308 ieee80211_plcp2rate(uint8_t plcp, enum ieee80211_phytype type) 309 { 310 if (type == IEEE80211_T_OFDM) { 311 static const uint8_t ofdm_plcp2rate[16] = { 312 [0xb] = 12, 313 [0xf] = 18, 314 [0xa] = 24, 315 [0xe] = 36, 316 [0x9] = 48, 317 [0xd] = 72, 318 [0x8] = 96, 319 [0xc] = 108 320 }; 321 return ofdm_plcp2rate[plcp & 0xf]; 322 } 323 if (type == IEEE80211_T_CCK) { 324 static const uint8_t cck_plcp2rate[16] = { 325 [0xa] = 2, /* 0x0a */ 326 [0x4] = 4, /* 0x14 */ 327 [0x7] = 11, /* 0x37 */ 328 [0xe] = 22, /* 0x6e */ 329 [0xc] = 44, /* 0xdc , actually PBCC */ 330 }; 331 return cck_plcp2rate[plcp & 0xf]; 332 } 333 return 0; 334 } 335 336 /* 337 * Covert 802.11 rate to PLCP signal. 338 */ 339 uint8_t 340 ieee80211_rate2plcp(int rate, enum ieee80211_phytype type) 341 { 342 /* XXX ignore type for now since rates are unique */ 343 switch (rate) { 344 /* OFDM rates (cf IEEE Std 802.11a-1999, pp. 14 Table 80) */ 345 case 12: return 0xb; 346 case 18: return 0xf; 347 case 24: return 0xa; 348 case 36: return 0xe; 349 case 48: return 0x9; 350 case 72: return 0xd; 351 case 96: return 0x8; 352 case 108: return 0xc; 353 /* CCK rates (IEEE Std 802.11b-1999 page 15, subclause 18.2.3.3) */ 354 case 2: return 10; 355 case 4: return 20; 356 case 11: return 55; 357 case 22: return 110; 358 /* IEEE Std 802.11g-2003 page 19, subclause 19.3.2.1 */ 359 case 44: return 220; 360 } 361 return 0; /* XXX unsupported/unknown rate */ 362 } 363 364 #define CCK_SIFS_TIME 10 365 #define CCK_PREAMBLE_BITS 144 366 #define CCK_PLCP_BITS 48 367 368 #define OFDM_SIFS_TIME 16 369 #define OFDM_PREAMBLE_TIME 20 370 #define OFDM_PLCP_BITS 22 371 #define OFDM_SYMBOL_TIME 4 372 373 #define OFDM_HALF_SIFS_TIME 32 374 #define OFDM_HALF_PREAMBLE_TIME 40 375 #define OFDM_HALF_PLCP_BITS 22 376 #define OFDM_HALF_SYMBOL_TIME 8 377 378 #define OFDM_QUARTER_SIFS_TIME 64 379 #define OFDM_QUARTER_PREAMBLE_TIME 80 380 #define OFDM_QUARTER_PLCP_BITS 22 381 #define OFDM_QUARTER_SYMBOL_TIME 16 382 383 #define TURBO_SIFS_TIME 8 384 #define TURBO_PREAMBLE_TIME 14 385 #define TURBO_PLCP_BITS 22 386 #define TURBO_SYMBOL_TIME 4 387 388 /* 389 * Compute the time to transmit a frame of length frameLen bytes 390 * using the specified rate, phy, and short preamble setting. 391 * SIFS is included. 392 */ 393 uint16_t 394 ieee80211_compute_duration(const struct ieee80211_rate_table *rt, 395 uint32_t frameLen, uint16_t rate, int isShortPreamble) 396 { 397 uint8_t rix = rt->rateCodeToIndex[rate]; 398 uint32_t bitsPerSymbol, numBits, numSymbols, phyTime, txTime; 399 uint32_t kbps; 400 401 KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate)); 402 kbps = rt->info[rix].rateKbps; 403 if (kbps == 0) /* XXX bandaid for channel changes */ 404 return 0; 405 406 switch (rt->info[rix].phy) { 407 case IEEE80211_T_CCK: 408 phyTime = CCK_PREAMBLE_BITS + CCK_PLCP_BITS; 409 if (isShortPreamble && rt->info[rix].shortPreamble) 410 phyTime >>= 1; 411 numBits = frameLen << 3; 412 txTime = CCK_SIFS_TIME + phyTime 413 + ((numBits * 1000)/kbps); 414 break; 415 case IEEE80211_T_OFDM: 416 bitsPerSymbol = (kbps * OFDM_SYMBOL_TIME) / 1000; 417 KASSERT(bitsPerSymbol != 0, ("full rate bps")); 418 419 numBits = OFDM_PLCP_BITS + (frameLen << 3); 420 numSymbols = howmany(numBits, bitsPerSymbol); 421 txTime = OFDM_SIFS_TIME 422 + OFDM_PREAMBLE_TIME 423 + (numSymbols * OFDM_SYMBOL_TIME); 424 break; 425 case IEEE80211_T_OFDM_HALF: 426 bitsPerSymbol = (kbps * OFDM_HALF_SYMBOL_TIME) / 1000; 427 KASSERT(bitsPerSymbol != 0, ("1/4 rate bps")); 428 429 numBits = OFDM_PLCP_BITS + (frameLen << 3); 430 numSymbols = howmany(numBits, bitsPerSymbol); 431 txTime = OFDM_HALF_SIFS_TIME 432 + OFDM_HALF_PREAMBLE_TIME 433 + (numSymbols * OFDM_HALF_SYMBOL_TIME); 434 break; 435 case IEEE80211_T_OFDM_QUARTER: 436 bitsPerSymbol = (kbps * OFDM_QUARTER_SYMBOL_TIME) / 1000; 437 KASSERT(bitsPerSymbol != 0, ("1/2 rate bps")); 438 439 numBits = OFDM_PLCP_BITS + (frameLen << 3); 440 numSymbols = howmany(numBits, bitsPerSymbol); 441 txTime = OFDM_QUARTER_SIFS_TIME 442 + OFDM_QUARTER_PREAMBLE_TIME 443 + (numSymbols * OFDM_QUARTER_SYMBOL_TIME); 444 break; 445 case IEEE80211_T_TURBO: 446 /* we still save OFDM rates in kbps - so double them */ 447 bitsPerSymbol = ((kbps << 1) * TURBO_SYMBOL_TIME) / 1000; 448 KASSERT(bitsPerSymbol != 0, ("turbo bps")); 449 450 numBits = TURBO_PLCP_BITS + (frameLen << 3); 451 numSymbols = howmany(numBits, bitsPerSymbol); 452 txTime = TURBO_SIFS_TIME + TURBO_PREAMBLE_TIME 453 + (numSymbols * TURBO_SYMBOL_TIME); 454 break; 455 default: 456 panic("%s: unknown phy %u (rate %u)", __func__, 457 rt->info[rix].phy, rate); 458 break; 459 } 460 return txTime; 461 } 462