1 /* 2 * Wireless utility functions 3 * 4 * Copyright 2007-2009 Johannes Berg <johannes@sipsolutions.net> 5 */ 6 #include <linux/bitops.h> 7 #include <linux/etherdevice.h> 8 #include <net/cfg80211.h> 9 #include <net/ip.h> 10 #include "core.h" 11 12 struct ieee80211_rate * 13 ieee80211_get_response_rate(struct ieee80211_supported_band *sband, 14 u32 basic_rates, int bitrate) 15 { 16 struct ieee80211_rate *result = &sband->bitrates[0]; 17 int i; 18 19 for (i = 0; i < sband->n_bitrates; i++) { 20 if (!(basic_rates & BIT(i))) 21 continue; 22 if (sband->bitrates[i].bitrate > bitrate) 23 continue; 24 result = &sband->bitrates[i]; 25 } 26 27 return result; 28 } 29 EXPORT_SYMBOL(ieee80211_get_response_rate); 30 31 int ieee80211_channel_to_frequency(int chan) 32 { 33 if (chan < 14) 34 return 2407 + chan * 5; 35 36 if (chan == 14) 37 return 2484; 38 39 /* FIXME: 802.11j 17.3.8.3.2 */ 40 return (chan + 1000) * 5; 41 } 42 EXPORT_SYMBOL(ieee80211_channel_to_frequency); 43 44 int ieee80211_frequency_to_channel(int freq) 45 { 46 if (freq == 2484) 47 return 14; 48 49 if (freq < 2484) 50 return (freq - 2407) / 5; 51 52 /* FIXME: 802.11j 17.3.8.3.2 */ 53 return freq/5 - 1000; 54 } 55 EXPORT_SYMBOL(ieee80211_frequency_to_channel); 56 57 struct ieee80211_channel *__ieee80211_get_channel(struct wiphy *wiphy, 58 int freq) 59 { 60 enum ieee80211_band band; 61 struct ieee80211_supported_band *sband; 62 int i; 63 64 for (band = 0; band < IEEE80211_NUM_BANDS; band++) { 65 sband = wiphy->bands[band]; 66 67 if (!sband) 68 continue; 69 70 for (i = 0; i < sband->n_channels; i++) { 71 if (sband->channels[i].center_freq == freq) 72 return &sband->channels[i]; 73 } 74 } 75 76 return NULL; 77 } 78 EXPORT_SYMBOL(__ieee80211_get_channel); 79 80 static void set_mandatory_flags_band(struct ieee80211_supported_band *sband, 81 enum ieee80211_band band) 82 { 83 int i, want; 84 85 switch (band) { 86 case IEEE80211_BAND_5GHZ: 87 want = 3; 88 for (i = 0; i < sband->n_bitrates; i++) { 89 if (sband->bitrates[i].bitrate == 60 || 90 sband->bitrates[i].bitrate == 120 || 91 sband->bitrates[i].bitrate == 240) { 92 sband->bitrates[i].flags |= 93 IEEE80211_RATE_MANDATORY_A; 94 want--; 95 } 96 } 97 WARN_ON(want); 98 break; 99 case IEEE80211_BAND_2GHZ: 100 want = 7; 101 for (i = 0; i < sband->n_bitrates; i++) { 102 if (sband->bitrates[i].bitrate == 10) { 103 sband->bitrates[i].flags |= 104 IEEE80211_RATE_MANDATORY_B | 105 IEEE80211_RATE_MANDATORY_G; 106 want--; 107 } 108 109 if (sband->bitrates[i].bitrate == 20 || 110 sband->bitrates[i].bitrate == 55 || 111 sband->bitrates[i].bitrate == 110 || 112 sband->bitrates[i].bitrate == 60 || 113 sband->bitrates[i].bitrate == 120 || 114 sband->bitrates[i].bitrate == 240) { 115 sband->bitrates[i].flags |= 116 IEEE80211_RATE_MANDATORY_G; 117 want--; 118 } 119 120 if (sband->bitrates[i].bitrate != 10 && 121 sband->bitrates[i].bitrate != 20 && 122 sband->bitrates[i].bitrate != 55 && 123 sband->bitrates[i].bitrate != 110) 124 sband->bitrates[i].flags |= 125 IEEE80211_RATE_ERP_G; 126 } 127 WARN_ON(want != 0 && want != 3 && want != 6); 128 break; 129 case IEEE80211_NUM_BANDS: 130 WARN_ON(1); 131 break; 132 } 133 } 134 135 void ieee80211_set_bitrate_flags(struct wiphy *wiphy) 136 { 137 enum ieee80211_band band; 138 139 for (band = 0; band < IEEE80211_NUM_BANDS; band++) 140 if (wiphy->bands[band]) 141 set_mandatory_flags_band(wiphy->bands[band], band); 142 } 143 144 int cfg80211_validate_key_settings(struct key_params *params, int key_idx, 145 const u8 *mac_addr) 146 { 147 if (key_idx > 5) 148 return -EINVAL; 149 150 /* 151 * Disallow pairwise keys with non-zero index unless it's WEP 152 * (because current deployments use pairwise WEP keys with 153 * non-zero indizes but 802.11i clearly specifies to use zero) 154 */ 155 if (mac_addr && key_idx && 156 params->cipher != WLAN_CIPHER_SUITE_WEP40 && 157 params->cipher != WLAN_CIPHER_SUITE_WEP104) 158 return -EINVAL; 159 160 switch (params->cipher) { 161 case WLAN_CIPHER_SUITE_WEP40: 162 if (params->key_len != WLAN_KEY_LEN_WEP40) 163 return -EINVAL; 164 break; 165 case WLAN_CIPHER_SUITE_TKIP: 166 if (params->key_len != WLAN_KEY_LEN_TKIP) 167 return -EINVAL; 168 break; 169 case WLAN_CIPHER_SUITE_CCMP: 170 if (params->key_len != WLAN_KEY_LEN_CCMP) 171 return -EINVAL; 172 break; 173 case WLAN_CIPHER_SUITE_WEP104: 174 if (params->key_len != WLAN_KEY_LEN_WEP104) 175 return -EINVAL; 176 break; 177 case WLAN_CIPHER_SUITE_AES_CMAC: 178 if (params->key_len != WLAN_KEY_LEN_AES_CMAC) 179 return -EINVAL; 180 break; 181 default: 182 return -EINVAL; 183 } 184 185 if (params->seq) { 186 switch (params->cipher) { 187 case WLAN_CIPHER_SUITE_WEP40: 188 case WLAN_CIPHER_SUITE_WEP104: 189 /* These ciphers do not use key sequence */ 190 return -EINVAL; 191 case WLAN_CIPHER_SUITE_TKIP: 192 case WLAN_CIPHER_SUITE_CCMP: 193 case WLAN_CIPHER_SUITE_AES_CMAC: 194 if (params->seq_len != 6) 195 return -EINVAL; 196 break; 197 } 198 } 199 200 return 0; 201 } 202 203 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */ 204 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */ 205 const unsigned char rfc1042_header[] __aligned(2) = 206 { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 }; 207 EXPORT_SYMBOL(rfc1042_header); 208 209 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */ 210 const unsigned char bridge_tunnel_header[] __aligned(2) = 211 { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 }; 212 EXPORT_SYMBOL(bridge_tunnel_header); 213 214 unsigned int ieee80211_hdrlen(__le16 fc) 215 { 216 unsigned int hdrlen = 24; 217 218 if (ieee80211_is_data(fc)) { 219 if (ieee80211_has_a4(fc)) 220 hdrlen = 30; 221 if (ieee80211_is_data_qos(fc)) 222 hdrlen += IEEE80211_QOS_CTL_LEN; 223 goto out; 224 } 225 226 if (ieee80211_is_ctl(fc)) { 227 /* 228 * ACK and CTS are 10 bytes, all others 16. To see how 229 * to get this condition consider 230 * subtype mask: 0b0000000011110000 (0x00F0) 231 * ACK subtype: 0b0000000011010000 (0x00D0) 232 * CTS subtype: 0b0000000011000000 (0x00C0) 233 * bits that matter: ^^^ (0x00E0) 234 * value of those: 0b0000000011000000 (0x00C0) 235 */ 236 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0)) 237 hdrlen = 10; 238 else 239 hdrlen = 16; 240 } 241 out: 242 return hdrlen; 243 } 244 EXPORT_SYMBOL(ieee80211_hdrlen); 245 246 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb) 247 { 248 const struct ieee80211_hdr *hdr = 249 (const struct ieee80211_hdr *)skb->data; 250 unsigned int hdrlen; 251 252 if (unlikely(skb->len < 10)) 253 return 0; 254 hdrlen = ieee80211_hdrlen(hdr->frame_control); 255 if (unlikely(hdrlen > skb->len)) 256 return 0; 257 return hdrlen; 258 } 259 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb); 260 261 static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr) 262 { 263 int ae = meshhdr->flags & MESH_FLAGS_AE; 264 /* 7.1.3.5a.2 */ 265 switch (ae) { 266 case 0: 267 return 6; 268 case 1: 269 return 12; 270 case 2: 271 return 18; 272 case 3: 273 return 24; 274 default: 275 return 6; 276 } 277 } 278 279 int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr, 280 enum nl80211_iftype iftype) 281 { 282 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 283 u16 hdrlen, ethertype; 284 u8 *payload; 285 u8 dst[ETH_ALEN]; 286 u8 src[ETH_ALEN] __aligned(2); 287 288 if (unlikely(!ieee80211_is_data_present(hdr->frame_control))) 289 return -1; 290 291 hdrlen = ieee80211_hdrlen(hdr->frame_control); 292 293 /* convert IEEE 802.11 header + possible LLC headers into Ethernet 294 * header 295 * IEEE 802.11 address fields: 296 * ToDS FromDS Addr1 Addr2 Addr3 Addr4 297 * 0 0 DA SA BSSID n/a 298 * 0 1 DA BSSID SA n/a 299 * 1 0 BSSID SA DA n/a 300 * 1 1 RA TA DA SA 301 */ 302 memcpy(dst, ieee80211_get_DA(hdr), ETH_ALEN); 303 memcpy(src, ieee80211_get_SA(hdr), ETH_ALEN); 304 305 switch (hdr->frame_control & 306 cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) { 307 case cpu_to_le16(IEEE80211_FCTL_TODS): 308 if (unlikely(iftype != NL80211_IFTYPE_AP && 309 iftype != NL80211_IFTYPE_AP_VLAN)) 310 return -1; 311 break; 312 case cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS): 313 if (unlikely(iftype != NL80211_IFTYPE_WDS && 314 iftype != NL80211_IFTYPE_MESH_POINT)) 315 return -1; 316 if (iftype == NL80211_IFTYPE_MESH_POINT) { 317 struct ieee80211s_hdr *meshdr = 318 (struct ieee80211s_hdr *) (skb->data + hdrlen); 319 hdrlen += ieee80211_get_mesh_hdrlen(meshdr); 320 if (meshdr->flags & MESH_FLAGS_AE_A5_A6) { 321 memcpy(dst, meshdr->eaddr1, ETH_ALEN); 322 memcpy(src, meshdr->eaddr2, ETH_ALEN); 323 } 324 } 325 break; 326 case cpu_to_le16(IEEE80211_FCTL_FROMDS): 327 if (iftype != NL80211_IFTYPE_STATION || 328 (is_multicast_ether_addr(dst) && 329 !compare_ether_addr(src, addr))) 330 return -1; 331 break; 332 case cpu_to_le16(0): 333 if (iftype != NL80211_IFTYPE_ADHOC) 334 return -1; 335 break; 336 } 337 338 if (unlikely(skb->len - hdrlen < 8)) 339 return -1; 340 341 payload = skb->data + hdrlen; 342 ethertype = (payload[6] << 8) | payload[7]; 343 344 if (likely((compare_ether_addr(payload, rfc1042_header) == 0 && 345 ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) || 346 compare_ether_addr(payload, bridge_tunnel_header) == 0)) { 347 /* remove RFC1042 or Bridge-Tunnel encapsulation and 348 * replace EtherType */ 349 skb_pull(skb, hdrlen + 6); 350 memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN); 351 memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN); 352 } else { 353 struct ethhdr *ehdr; 354 __be16 len; 355 356 skb_pull(skb, hdrlen); 357 len = htons(skb->len); 358 ehdr = (struct ethhdr *) skb_push(skb, sizeof(struct ethhdr)); 359 memcpy(ehdr->h_dest, dst, ETH_ALEN); 360 memcpy(ehdr->h_source, src, ETH_ALEN); 361 ehdr->h_proto = len; 362 } 363 return 0; 364 } 365 EXPORT_SYMBOL(ieee80211_data_to_8023); 366 367 int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr, 368 enum nl80211_iftype iftype, u8 *bssid, bool qos) 369 { 370 struct ieee80211_hdr hdr; 371 u16 hdrlen, ethertype; 372 __le16 fc; 373 const u8 *encaps_data; 374 int encaps_len, skip_header_bytes; 375 int nh_pos, h_pos; 376 int head_need; 377 378 if (unlikely(skb->len < ETH_HLEN)) 379 return -EINVAL; 380 381 nh_pos = skb_network_header(skb) - skb->data; 382 h_pos = skb_transport_header(skb) - skb->data; 383 384 /* convert Ethernet header to proper 802.11 header (based on 385 * operation mode) */ 386 ethertype = (skb->data[12] << 8) | skb->data[13]; 387 fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA); 388 389 switch (iftype) { 390 case NL80211_IFTYPE_AP: 391 case NL80211_IFTYPE_AP_VLAN: 392 fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS); 393 /* DA BSSID SA */ 394 memcpy(hdr.addr1, skb->data, ETH_ALEN); 395 memcpy(hdr.addr2, addr, ETH_ALEN); 396 memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN); 397 hdrlen = 24; 398 break; 399 case NL80211_IFTYPE_STATION: 400 fc |= cpu_to_le16(IEEE80211_FCTL_TODS); 401 /* BSSID SA DA */ 402 memcpy(hdr.addr1, bssid, ETH_ALEN); 403 memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN); 404 memcpy(hdr.addr3, skb->data, ETH_ALEN); 405 hdrlen = 24; 406 break; 407 case NL80211_IFTYPE_ADHOC: 408 /* DA SA BSSID */ 409 memcpy(hdr.addr1, skb->data, ETH_ALEN); 410 memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN); 411 memcpy(hdr.addr3, bssid, ETH_ALEN); 412 hdrlen = 24; 413 break; 414 default: 415 return -EOPNOTSUPP; 416 } 417 418 if (qos) { 419 fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA); 420 hdrlen += 2; 421 } 422 423 hdr.frame_control = fc; 424 hdr.duration_id = 0; 425 hdr.seq_ctrl = 0; 426 427 skip_header_bytes = ETH_HLEN; 428 if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) { 429 encaps_data = bridge_tunnel_header; 430 encaps_len = sizeof(bridge_tunnel_header); 431 skip_header_bytes -= 2; 432 } else if (ethertype > 0x600) { 433 encaps_data = rfc1042_header; 434 encaps_len = sizeof(rfc1042_header); 435 skip_header_bytes -= 2; 436 } else { 437 encaps_data = NULL; 438 encaps_len = 0; 439 } 440 441 skb_pull(skb, skip_header_bytes); 442 nh_pos -= skip_header_bytes; 443 h_pos -= skip_header_bytes; 444 445 head_need = hdrlen + encaps_len - skb_headroom(skb); 446 447 if (head_need > 0 || skb_cloned(skb)) { 448 head_need = max(head_need, 0); 449 if (head_need) 450 skb_orphan(skb); 451 452 if (pskb_expand_head(skb, head_need, 0, GFP_ATOMIC)) { 453 printk(KERN_ERR "failed to reallocate Tx buffer\n"); 454 return -ENOMEM; 455 } 456 skb->truesize += head_need; 457 } 458 459 if (encaps_data) { 460 memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len); 461 nh_pos += encaps_len; 462 h_pos += encaps_len; 463 } 464 465 memcpy(skb_push(skb, hdrlen), &hdr, hdrlen); 466 467 nh_pos += hdrlen; 468 h_pos += hdrlen; 469 470 /* Update skb pointers to various headers since this modified frame 471 * is going to go through Linux networking code that may potentially 472 * need things like pointer to IP header. */ 473 skb_set_mac_header(skb, 0); 474 skb_set_network_header(skb, nh_pos); 475 skb_set_transport_header(skb, h_pos); 476 477 return 0; 478 } 479 EXPORT_SYMBOL(ieee80211_data_from_8023); 480 481 /* Given a data frame determine the 802.1p/1d tag to use. */ 482 unsigned int cfg80211_classify8021d(struct sk_buff *skb) 483 { 484 unsigned int dscp; 485 486 /* skb->priority values from 256->263 are magic values to 487 * directly indicate a specific 802.1d priority. This is used 488 * to allow 802.1d priority to be passed directly in from VLAN 489 * tags, etc. 490 */ 491 if (skb->priority >= 256 && skb->priority <= 263) 492 return skb->priority - 256; 493 494 switch (skb->protocol) { 495 case htons(ETH_P_IP): 496 dscp = ip_hdr(skb)->tos & 0xfc; 497 break; 498 default: 499 return 0; 500 } 501 502 return dscp >> 5; 503 } 504 EXPORT_SYMBOL(cfg80211_classify8021d); 505