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 * $DragonFly$ 27 */ 28 29 /* 30 * IEEE 802.11 PHY-related support. 31 */ 32 33 #include "opt_inet.h" 34 35 #include <sys/param.h> 36 #include <sys/kernel.h> 37 #include <sys/systm.h> 38 39 #include <sys/socket.h> 40 41 #include <net/if.h> 42 #include <net/if_media.h> 43 #include <net/route.h> 44 45 #include <netproto/802_11/ieee80211_var.h> 46 #include <netproto/802_11/ieee80211_phy.h> 47 48 #ifdef notyet 49 struct ieee80211_ds_plcp_hdr { 50 uint8_t i_signal; 51 uint8_t i_service; 52 uint16_t i_length; 53 uint16_t i_crc; 54 } __packed; 55 56 #endif /* notyet */ 57 58 /* shorthands to compact tables for readability */ 59 #define OFDM IEEE80211_T_OFDM 60 #define CCK IEEE80211_T_CCK 61 #define TURBO IEEE80211_T_TURBO 62 #define HALF IEEE80211_T_OFDM_HALF 63 #define QUART IEEE80211_T_OFDM_QUARTER 64 #define PBCC (IEEE80211_T_OFDM_QUARTER+1) /* XXX */ 65 #define B(r) (0x80 | r) 66 #define Mb(x) (x*1000) 67 68 static struct ieee80211_rate_table ieee80211_11b_table = { 69 .rateCount = 4, /* XXX no PBCC */ 70 .info = { 71 /* short ctrl */ 72 /* Preamble dot11Rate Rate */ 73 [0] = { .phy = CCK, 1000, 0x00, B(2), 0 },/* 1 Mb */ 74 [1] = { .phy = CCK, 2000, 0x04, B(4), 1 },/* 2 Mb */ 75 [2] = { .phy = CCK, 5500, 0x04, B(11), 1 },/* 5.5 Mb */ 76 [3] = { .phy = CCK, 11000, 0x04, B(22), 1 },/* 11 Mb */ 77 [4] = { .phy = PBCC, 22000, 0x04, 44, 3 } /* 22 Mb */ 78 }, 79 }; 80 81 static struct ieee80211_rate_table ieee80211_11g_table = { 82 .rateCount = 12, 83 .info = { 84 /* short ctrl */ 85 /* Preamble dot11Rate Rate */ 86 [0] = { .phy = CCK, 1000, 0x00, B(2), 0 }, 87 [1] = { .phy = CCK, 2000, 0x04, B(4), 1 }, 88 [2] = { .phy = CCK, 5500, 0x04, B(11), 2 }, 89 [3] = { .phy = CCK, 11000, 0x04, B(22), 3 }, 90 [4] = { .phy = OFDM, 6000, 0x00, 12, 4 }, 91 [5] = { .phy = OFDM, 9000, 0x00, 18, 4 }, 92 [6] = { .phy = OFDM, 12000, 0x00, 24, 6 }, 93 [7] = { .phy = OFDM, 18000, 0x00, 36, 6 }, 94 [8] = { .phy = OFDM, 24000, 0x00, 48, 8 }, 95 [9] = { .phy = OFDM, 36000, 0x00, 72, 8 }, 96 [10] = { .phy = OFDM, 48000, 0x00, 96, 8 }, 97 [11] = { .phy = OFDM, 54000, 0x00, 108, 8 } 98 }, 99 }; 100 101 static struct ieee80211_rate_table ieee80211_11a_table = { 102 .rateCount = 8, 103 .info = { 104 /* short ctrl */ 105 /* Preamble dot11Rate Rate */ 106 [0] = { .phy = OFDM, 6000, 0x00, B(12), 0 }, 107 [1] = { .phy = OFDM, 9000, 0x00, 18, 0 }, 108 [2] = { .phy = OFDM, 12000, 0x00, B(24), 2 }, 109 [3] = { .phy = OFDM, 18000, 0x00, 36, 2 }, 110 [4] = { .phy = OFDM, 24000, 0x00, B(48), 4 }, 111 [5] = { .phy = OFDM, 36000, 0x00, 72, 4 }, 112 [6] = { .phy = OFDM, 48000, 0x00, 96, 4 }, 113 [7] = { .phy = OFDM, 54000, 0x00, 108, 4 } 114 }, 115 }; 116 117 static struct ieee80211_rate_table ieee80211_half_table = { 118 .rateCount = 8, 119 .info = { 120 /* short ctrl */ 121 /* Preamble dot11Rate Rate */ 122 [0] = { .phy = HALF, 3000, 0x00, B(6), 0 }, 123 [1] = { .phy = HALF, 4500, 0x00, 9, 0 }, 124 [2] = { .phy = HALF, 6000, 0x00, B(12), 2 }, 125 [3] = { .phy = HALF, 9000, 0x00, 18, 2 }, 126 [4] = { .phy = HALF, 12000, 0x00, B(24), 4 }, 127 [5] = { .phy = HALF, 18000, 0x00, 36, 4 }, 128 [6] = { .phy = HALF, 24000, 0x00, 48, 4 }, 129 [7] = { .phy = HALF, 27000, 0x00, 54, 4 } 130 }, 131 }; 132 133 static struct ieee80211_rate_table ieee80211_quarter_table = { 134 .rateCount = 8, 135 .info = { 136 /* short ctrl */ 137 /* Preamble dot11Rate Rate */ 138 [0] = { .phy = QUART, 1500, 0x00, B(3), 0 }, 139 [1] = { .phy = QUART, 2250, 0x00, 4, 0 }, 140 [2] = { .phy = QUART, 3000, 0x00, B(9), 2 }, 141 [3] = { .phy = QUART, 4500, 0x00, 9, 2 }, 142 [4] = { .phy = QUART, 6000, 0x00, B(12), 4 }, 143 [5] = { .phy = QUART, 9000, 0x00, 18, 4 }, 144 [6] = { .phy = QUART, 12000, 0x00, 24, 4 }, 145 [7] = { .phy = QUART, 13500, 0x00, 27, 4 } 146 }, 147 }; 148 149 static struct ieee80211_rate_table ieee80211_turbog_table = { 150 .rateCount = 7, 151 .info = { 152 /* short ctrl */ 153 /* Preamble dot11Rate Rate */ 154 [0] = { .phy = TURBO, 12000, 0x00, B(12), 0 }, 155 [1] = { .phy = TURBO, 24000, 0x00, B(24), 1 }, 156 [2] = { .phy = TURBO, 36000, 0x00, 36, 1 }, 157 [3] = { .phy = TURBO, 48000, 0x00, B(48), 3 }, 158 [4] = { .phy = TURBO, 72000, 0x00, 72, 3 }, 159 [5] = { .phy = TURBO, 96000, 0x00, 96, 3 }, 160 [6] = { .phy = TURBO, 108000, 0x00, 108, 3 } 161 }, 162 }; 163 164 static struct ieee80211_rate_table ieee80211_turboa_table = { 165 .rateCount = 8, 166 .info = { 167 /* short ctrl */ 168 /* Preamble dot11Rate Rate */ 169 [0] = { .phy = TURBO, 12000, 0x00, B(12), 0 }, 170 [1] = { .phy = TURBO, 18000, 0x00, 18, 0 }, 171 [2] = { .phy = TURBO, 24000, 0x00, B(24), 2 }, 172 [3] = { .phy = TURBO, 36000, 0x00, 36, 2 }, 173 [4] = { .phy = TURBO, 48000, 0x00, B(48), 4 }, 174 [5] = { .phy = TURBO, 72000, 0x00, 72, 4 }, 175 [6] = { .phy = TURBO, 96000, 0x00, 96, 4 }, 176 [7] = { .phy = TURBO, 108000, 0x00, 108, 4 } 177 }, 178 }; 179 180 #undef Mb 181 #undef B 182 #undef OFDM 183 #undef HALF 184 #undef QUART 185 #undef CCK 186 #undef TURBO 187 #undef XR 188 189 /* 190 * Setup a rate table's reverse lookup table and fill in 191 * ack durations. The reverse lookup tables are assumed 192 * to be initialized to zero (or at least the first entry). 193 * We use this as a key that indicates whether or not 194 * we've previously setup the reverse lookup table. 195 * 196 * XXX not reentrant, but shouldn't matter 197 */ 198 static void 199 ieee80211_setup_ratetable(struct ieee80211_rate_table *rt) 200 { 201 #define WLAN_CTRL_FRAME_SIZE \ 202 (sizeof(struct ieee80211_frame_ack) + IEEE80211_CRC_LEN) 203 204 int i; 205 206 for (i = 0; i < NELEM(rt->rateCodeToIndex); i++) 207 rt->rateCodeToIndex[i] = (uint8_t) -1; 208 for (i = 0; i < rt->rateCount; i++) { 209 uint8_t code = rt->info[i].dot11Rate; 210 uint8_t cix = rt->info[i].ctlRateIndex; 211 uint8_t ctl_rate = rt->info[cix].dot11Rate; 212 213 rt->rateCodeToIndex[code] = i; 214 if (code & IEEE80211_RATE_BASIC) { 215 /* 216 * Map w/o basic rate bit too. 217 */ 218 code &= IEEE80211_RATE_VAL; 219 rt->rateCodeToIndex[code] = i; 220 } 221 222 /* 223 * XXX for 11g the control rate to use for 5.5 and 11 Mb/s 224 * depends on whether they are marked as basic rates; 225 * the static tables are setup with an 11b-compatible 226 * 2Mb/s rate which will work but is suboptimal 227 * 228 * NB: Control rate is always less than or equal to the 229 * current rate, so control rate's reverse lookup entry 230 * has been installed and following call is safe. 231 */ 232 rt->info[i].lpAckDuration = ieee80211_compute_duration(rt, 233 WLAN_CTRL_FRAME_SIZE, ctl_rate, 0); 234 rt->info[i].spAckDuration = ieee80211_compute_duration(rt, 235 WLAN_CTRL_FRAME_SIZE, ctl_rate, IEEE80211_F_SHPREAMBLE); 236 } 237 238 #undef WLAN_CTRL_FRAME_SIZE 239 } 240 241 /* Setup all rate tables */ 242 static void 243 ieee80211_phy_init(void) 244 { 245 static struct ieee80211_rate_table * const ratetables[] = { 246 &ieee80211_half_table, 247 &ieee80211_quarter_table, 248 &ieee80211_11a_table, 249 &ieee80211_11g_table, 250 &ieee80211_turbog_table, 251 &ieee80211_turboa_table, 252 &ieee80211_turboa_table, 253 &ieee80211_11a_table, 254 &ieee80211_11g_table, 255 &ieee80211_11b_table 256 }; 257 int i; 258 259 for (i = 0; i < NELEM(ratetables); ++i) 260 ieee80211_setup_ratetable(ratetables[i]); 261 262 } 263 SYSINIT(wlan_phy, SI_SUB_DRIVERS, SI_ORDER_FIRST, ieee80211_phy_init, NULL); 264 265 const struct ieee80211_rate_table * 266 ieee80211_get_ratetable(struct ieee80211_channel *c) 267 { 268 const struct ieee80211_rate_table *rt; 269 270 /* XXX HT */ 271 if (IEEE80211_IS_CHAN_HALF(c)) 272 rt = &ieee80211_half_table; 273 else if (IEEE80211_IS_CHAN_QUARTER(c)) 274 rt = &ieee80211_quarter_table; 275 else if (IEEE80211_IS_CHAN_HTA(c)) 276 rt = &ieee80211_11a_table; /* XXX */ 277 else if (IEEE80211_IS_CHAN_HTG(c)) 278 rt = &ieee80211_11g_table; /* XXX */ 279 else if (IEEE80211_IS_CHAN_108G(c)) 280 rt = &ieee80211_turbog_table; 281 else if (IEEE80211_IS_CHAN_ST(c)) 282 rt = &ieee80211_turboa_table; 283 else if (IEEE80211_IS_CHAN_TURBO(c)) 284 rt = &ieee80211_turboa_table; 285 else if (IEEE80211_IS_CHAN_A(c)) 286 rt = &ieee80211_11a_table; 287 else if (IEEE80211_IS_CHAN_ANYG(c)) 288 rt = &ieee80211_11g_table; 289 else if (IEEE80211_IS_CHAN_B(c)) 290 rt = &ieee80211_11b_table; 291 else { 292 /* NB: should not get here */ 293 panic("%s: no rate table for channel; freq %u flags 0x%x\n", 294 __func__, c->ic_freq, c->ic_flags); 295 } 296 return rt; 297 } 298 299 /* 300 * Convert PLCP signal/rate field to 802.11 rate (.5Mbits/s) 301 * 302 * Note we do no parameter checking; this routine is mainly 303 * used to derive an 802.11 rate for constructing radiotap 304 * header data for rx frames. 305 * 306 * XXX might be a candidate for inline 307 */ 308 uint8_t 309 ieee80211_plcp2rate(uint8_t plcp, enum ieee80211_phytype type) 310 { 311 if (type == IEEE80211_T_OFDM) { 312 static const uint8_t ofdm_plcp2rate[16] = { 313 [0xb] = 12, 314 [0xf] = 18, 315 [0xa] = 24, 316 [0xe] = 36, 317 [0x9] = 48, 318 [0xd] = 72, 319 [0x8] = 96, 320 [0xc] = 108 321 }; 322 return ofdm_plcp2rate[plcp & 0xf]; 323 } 324 if (type == IEEE80211_T_CCK) { 325 static const uint8_t cck_plcp2rate[16] = { 326 [0xa] = 2, /* 0x0a */ 327 [0x4] = 4, /* 0x14 */ 328 [0x7] = 11, /* 0x37 */ 329 [0xe] = 22, /* 0x6e */ 330 [0xc] = 44, /* 0xdc , actually PBCC */ 331 }; 332 return cck_plcp2rate[plcp & 0xf]; 333 } 334 return 0; 335 } 336 337 /* 338 * Covert 802.11 rate to PLCP signal. 339 */ 340 uint8_t 341 ieee80211_rate2plcp(int rate, enum ieee80211_phytype type) 342 { 343 /* XXX ignore type for now since rates are unique */ 344 switch (rate) { 345 /* OFDM rates (cf IEEE Std 802.11a-1999, pp. 14 Table 80) */ 346 case 12: return 0xb; 347 case 18: return 0xf; 348 case 24: return 0xa; 349 case 36: return 0xe; 350 case 48: return 0x9; 351 case 72: return 0xd; 352 case 96: return 0x8; 353 case 108: return 0xc; 354 /* CCK rates (IEEE Std 802.11b-1999 page 15, subclause 18.2.3.3) */ 355 case 2: return 10; 356 case 4: return 20; 357 case 11: return 55; 358 case 22: return 110; 359 /* IEEE Std 802.11g-2003 page 19, subclause 19.3.2.1 */ 360 case 44: return 220; 361 } 362 return 0; /* XXX unsupported/unknown rate */ 363 } 364 365 #define CCK_SIFS_TIME 10 366 #define CCK_PREAMBLE_BITS 144 367 #define CCK_PLCP_BITS 48 368 369 #define OFDM_SIFS_TIME 16 370 #define OFDM_PREAMBLE_TIME 20 371 #define OFDM_PLCP_BITS 22 372 #define OFDM_SYMBOL_TIME 4 373 374 #define OFDM_HALF_SIFS_TIME 32 375 #define OFDM_HALF_PREAMBLE_TIME 40 376 #define OFDM_HALF_PLCP_BITS 22 377 #define OFDM_HALF_SYMBOL_TIME 8 378 379 #define OFDM_QUARTER_SIFS_TIME 64 380 #define OFDM_QUARTER_PREAMBLE_TIME 80 381 #define OFDM_QUARTER_PLCP_BITS 22 382 #define OFDM_QUARTER_SYMBOL_TIME 16 383 384 #define TURBO_SIFS_TIME 8 385 #define TURBO_PREAMBLE_TIME 14 386 #define TURBO_PLCP_BITS 22 387 #define TURBO_SYMBOL_TIME 4 388 389 /* 390 * Compute the time to transmit a frame of length frameLen bytes 391 * using the specified rate, phy, and short preamble setting. 392 * SIFS is included. 393 */ 394 uint16_t 395 ieee80211_compute_duration(const struct ieee80211_rate_table *rt, 396 uint32_t frameLen, uint16_t rate, int isShortPreamble) 397 { 398 uint8_t rix = rt->rateCodeToIndex[rate]; 399 uint32_t bitsPerSymbol, numBits, numSymbols, phyTime, txTime; 400 uint32_t kbps; 401 402 KASSERT(rix != (uint8_t)-1, ("rate %d has no info", rate)); 403 kbps = rt->info[rix].rateKbps; 404 if (kbps == 0) /* XXX bandaid for channel changes */ 405 return 0; 406 407 switch (rt->info[rix].phy) { 408 case IEEE80211_T_CCK: 409 phyTime = CCK_PREAMBLE_BITS + CCK_PLCP_BITS; 410 if (isShortPreamble && rt->info[rix].shortPreamble) 411 phyTime >>= 1; 412 numBits = frameLen << 3; 413 txTime = CCK_SIFS_TIME + phyTime 414 + ((numBits * 1000)/kbps); 415 break; 416 case IEEE80211_T_OFDM: 417 bitsPerSymbol = (kbps * OFDM_SYMBOL_TIME) / 1000; 418 KASSERT(bitsPerSymbol != 0, ("full rate bps")); 419 420 numBits = OFDM_PLCP_BITS + (frameLen << 3); 421 numSymbols = howmany(numBits, bitsPerSymbol); 422 txTime = OFDM_SIFS_TIME 423 + OFDM_PREAMBLE_TIME 424 + (numSymbols * OFDM_SYMBOL_TIME); 425 break; 426 case IEEE80211_T_OFDM_HALF: 427 bitsPerSymbol = (kbps * OFDM_HALF_SYMBOL_TIME) / 1000; 428 KASSERT(bitsPerSymbol != 0, ("1/4 rate bps")); 429 430 numBits = OFDM_PLCP_BITS + (frameLen << 3); 431 numSymbols = howmany(numBits, bitsPerSymbol); 432 txTime = OFDM_HALF_SIFS_TIME 433 + OFDM_HALF_PREAMBLE_TIME 434 + (numSymbols * OFDM_HALF_SYMBOL_TIME); 435 break; 436 case IEEE80211_T_OFDM_QUARTER: 437 bitsPerSymbol = (kbps * OFDM_QUARTER_SYMBOL_TIME) / 1000; 438 KASSERT(bitsPerSymbol != 0, ("1/2 rate bps")); 439 440 numBits = OFDM_PLCP_BITS + (frameLen << 3); 441 numSymbols = howmany(numBits, bitsPerSymbol); 442 txTime = OFDM_QUARTER_SIFS_TIME 443 + OFDM_QUARTER_PREAMBLE_TIME 444 + (numSymbols * OFDM_QUARTER_SYMBOL_TIME); 445 break; 446 case IEEE80211_T_TURBO: 447 /* we still save OFDM rates in kbps - so double them */ 448 bitsPerSymbol = ((kbps << 1) * TURBO_SYMBOL_TIME) / 1000; 449 KASSERT(bitsPerSymbol != 0, ("turbo bps")); 450 451 numBits = TURBO_PLCP_BITS + (frameLen << 3); 452 numSymbols = howmany(numBits, bitsPerSymbol); 453 txTime = TURBO_SIFS_TIME + TURBO_PREAMBLE_TIME 454 + (numSymbols * TURBO_SYMBOL_TIME); 455 break; 456 default: 457 panic("%s: unknown phy %u (rate %u)\n", __func__, 458 rt->info[rix].phy, rate); 459 break; 460 } 461 return txTime; 462 } 463