net/wireless/util.c

   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 cfg80211_registered_device *rdev,
 145                                    struct key_params *params, int key_idx,
 146                                    const u8 *mac_addr)
 147 {
 148         int i;
 149
 150         if (key_idx > 5)
 151                 return -EINVAL;
 152
 153         /*
 154          * Disallow pairwise keys with non-zero index unless it's WEP
 155          * (because current deployments use pairwise WEP keys with
 156          * non-zero indizes but 802.11i clearly specifies to use zero)
 157          */
 158         if (mac_addr && key_idx &&
 159             params->cipher != WLAN_CIPHER_SUITE_WEP40 &&
 160             params->cipher != WLAN_CIPHER_SUITE_WEP104)
 161                 return -EINVAL;
 162
 163         switch (params->cipher) {
 164         case WLAN_CIPHER_SUITE_WEP40:
 165                 if (params->key_len != WLAN_KEY_LEN_WEP40)
 166                         return -EINVAL;
 167                 break;
 168         case WLAN_CIPHER_SUITE_TKIP:
 169                 if (params->key_len != WLAN_KEY_LEN_TKIP)
 170                         return -EINVAL;
 171                 break;
 172         case WLAN_CIPHER_SUITE_CCMP:
 173                 if (params->key_len != WLAN_KEY_LEN_CCMP)
 174                         return -EINVAL;
 175                 break;
 176         case WLAN_CIPHER_SUITE_WEP104:
 177                 if (params->key_len != WLAN_KEY_LEN_WEP104)
 178                         return -EINVAL;
 179                 break;
 180         case WLAN_CIPHER_SUITE_AES_CMAC:
 181                 if (params->key_len != WLAN_KEY_LEN_AES_CMAC)
 182                         return -EINVAL;
 183                 break;
 184         default:
 185                 return -EINVAL;
 186         }
 187
 188         if (params->seq) {
 189                 switch (params->cipher) {
 190                 case WLAN_CIPHER_SUITE_WEP40:
 191                 case WLAN_CIPHER_SUITE_WEP104:
 192                         /* These ciphers do not use key sequence */
 193                         return -EINVAL;
 194                 case WLAN_CIPHER_SUITE_TKIP:
 195                 case WLAN_CIPHER_SUITE_CCMP:
 196                 case WLAN_CIPHER_SUITE_AES_CMAC:
 197                         if (params->seq_len != 6)
 198                                 return -EINVAL;
 199                         break;
 200                 }
 201         }
 202
 203         for (i = 0; i < rdev->wiphy.n_cipher_suites; i++)
 204                 if (params->cipher == rdev->wiphy.cipher_suites[i])
 205                         break;
 206         if (i == rdev->wiphy.n_cipher_suites)
 207                 return -EINVAL;
 208
 209         return 0;
 210 }
 211
 212 /* See IEEE 802.1H for LLC/SNAP encapsulation/decapsulation */
 213 /* Ethernet-II snap header (RFC1042 for most EtherTypes) */
 214 const unsigned char rfc1042_header[] __aligned(2) =
 215         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0x00 };
 216 EXPORT_SYMBOL(rfc1042_header);
 217
 218 /* Bridge-Tunnel header (for EtherTypes ETH_P_AARP and ETH_P_IPX) */
 219 const unsigned char bridge_tunnel_header[] __aligned(2) =
 220         { 0xaa, 0xaa, 0x03, 0x00, 0x00, 0xf8 };
 221 EXPORT_SYMBOL(bridge_tunnel_header);
 222
 223 unsigned int ieee80211_hdrlen(__le16 fc)
 224 {
 225         unsigned int hdrlen = 24;
 226
 227         if (ieee80211_is_data(fc)) {
 228                 if (ieee80211_has_a4(fc))
 229                         hdrlen = 30;
 230                 if (ieee80211_is_data_qos(fc))
 231                         hdrlen += IEEE80211_QOS_CTL_LEN;
 232                 goto out;
 233         }
 234
 235         if (ieee80211_is_ctl(fc)) {
 236                 /*
 237                  * ACK and CTS are 10 bytes, all others 16. To see how
 238                  * to get this condition consider
 239                  *   subtype mask:   0b0000000011110000 (0x00F0)
 240                  *   ACK subtype:    0b0000000011010000 (0x00D0)
 241                  *   CTS subtype:    0b0000000011000000 (0x00C0)
 242                  *   bits that matter:         ^^^      (0x00E0)
 243                  *   value of those: 0b0000000011000000 (0x00C0)
 244                  */
 245                 if ((fc & cpu_to_le16(0x00E0)) == cpu_to_le16(0x00C0))
 246                         hdrlen = 10;
 247                 else
 248                         hdrlen = 16;
 249         }
 250 out:
 251         return hdrlen;
 252 }
 253 EXPORT_SYMBOL(ieee80211_hdrlen);
 254
 255 unsigned int ieee80211_get_hdrlen_from_skb(const struct sk_buff *skb)
 256 {
 257         const struct ieee80211_hdr *hdr =
 258                         (const struct ieee80211_hdr *)skb->data;
 259         unsigned int hdrlen;
 260
 261         if (unlikely(skb->len < 10))
 262                 return 0;
 263         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 264         if (unlikely(hdrlen > skb->len))
 265                 return 0;
 266         return hdrlen;
 267 }
 268 EXPORT_SYMBOL(ieee80211_get_hdrlen_from_skb);
 269
 270 static int ieee80211_get_mesh_hdrlen(struct ieee80211s_hdr *meshhdr)
 271 {
 272         int ae = meshhdr->flags & MESH_FLAGS_AE;
 273         /* 7.1.3.5a.2 */
 274         switch (ae) {
 275         case 0:
 276                 return 6;
 277         case 1:
 278                 return 12;
 279         case 2:
 280                 return 18;
 281         case 3:
 282                 return 24;
 283         default:
 284                 return 6;
 285         }
 286 }
 287
 288 int ieee80211_data_to_8023(struct sk_buff *skb, u8 *addr,
 289                            enum nl80211_iftype iftype)
 290 {
 291         struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
 292         u16 hdrlen, ethertype;
 293         u8 *payload;
 294         u8 dst[ETH_ALEN];
 295         u8 src[ETH_ALEN] __aligned(2);
 296
 297         if (unlikely(!ieee80211_is_data_present(hdr->frame_control)))
 298                 return -1;
 299
 300         hdrlen = ieee80211_hdrlen(hdr->frame_control);
 301
 302         /* convert IEEE 802.11 header + possible LLC headers into Ethernet
 303          * header
 304          * IEEE 802.11 address fields:
 305          * ToDS FromDS Addr1 Addr2 Addr3 Addr4
 306          *   0     0   DA    SA    BSSID n/a
 307          *   0     1   DA    BSSID SA    n/a
 308          *   1     0   BSSID SA    DA    n/a
 309          *   1     1   RA    TA    DA    SA
 310          */
 311         memcpy(dst, ieee80211_get_DA(hdr), ETH_ALEN);
 312         memcpy(src, ieee80211_get_SA(hdr), ETH_ALEN);
 313
 314         switch (hdr->frame_control &
 315                 cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS)) {
 316         case cpu_to_le16(IEEE80211_FCTL_TODS):
 317                 if (unlikely(iftype != NL80211_IFTYPE_AP &&
 318                              iftype != NL80211_IFTYPE_AP_VLAN))
 319                         return -1;
 320                 break;
 321         case cpu_to_le16(IEEE80211_FCTL_TODS | IEEE80211_FCTL_FROMDS):
 322                 if (unlikely(iftype != NL80211_IFTYPE_WDS &&
 323                              iftype != NL80211_IFTYPE_MESH_POINT))
 324                         return -1;
 325                 if (iftype == NL80211_IFTYPE_MESH_POINT) {
 326                         struct ieee80211s_hdr *meshdr =
 327                                 (struct ieee80211s_hdr *) (skb->data + hdrlen);
 328                         hdrlen += ieee80211_get_mesh_hdrlen(meshdr);
 329                         if (meshdr->flags & MESH_FLAGS_AE_A5_A6) {
 330                                 memcpy(dst, meshdr->eaddr1, ETH_ALEN);
 331                                 memcpy(src, meshdr->eaddr2, ETH_ALEN);
 332                         }
 333                 }
 334                 break;
 335         case cpu_to_le16(IEEE80211_FCTL_FROMDS):
 336                 if (iftype != NL80211_IFTYPE_STATION ||
 337                     (is_multicast_ether_addr(dst) &&
 338                      !compare_ether_addr(src, addr)))
 339                         return -1;
 340                 break;
 341         case cpu_to_le16(0):
 342                 if (iftype != NL80211_IFTYPE_ADHOC)
 343                         return -1;
 344                 break;
 345         }
 346
 347         if (unlikely(skb->len - hdrlen < 8))
 348                 return -1;
 349
 350         payload = skb->data + hdrlen;
 351         ethertype = (payload[6] << 8) | payload[7];
 352
 353         if (likely((compare_ether_addr(payload, rfc1042_header) == 0 &&
 354                     ethertype != ETH_P_AARP && ethertype != ETH_P_IPX) ||
 355                    compare_ether_addr(payload, bridge_tunnel_header) == 0)) {
 356                 /* remove RFC1042 or Bridge-Tunnel encapsulation and
 357                  * replace EtherType */
 358                 skb_pull(skb, hdrlen + 6);
 359                 memcpy(skb_push(skb, ETH_ALEN), src, ETH_ALEN);
 360                 memcpy(skb_push(skb, ETH_ALEN), dst, ETH_ALEN);
 361         } else {
 362                 struct ethhdr *ehdr;
 363                 __be16 len;
 364
 365                 skb_pull(skb, hdrlen);
 366                 len = htons(skb->len);
 367                 ehdr = (struct ethhdr *) skb_push(skb, sizeof(struct ethhdr));
 368                 memcpy(ehdr->h_dest, dst, ETH_ALEN);
 369                 memcpy(ehdr->h_source, src, ETH_ALEN);
 370                 ehdr->h_proto = len;
 371         }
 372         return 0;
 373 }
 374 EXPORT_SYMBOL(ieee80211_data_to_8023);
 375
 376 int ieee80211_data_from_8023(struct sk_buff *skb, u8 *addr,
 377                              enum nl80211_iftype iftype, u8 *bssid, bool qos)
 378 {
 379         struct ieee80211_hdr hdr;
 380         u16 hdrlen, ethertype;
 381         __le16 fc;
 382         const u8 *encaps_data;
 383         int encaps_len, skip_header_bytes;
 384         int nh_pos, h_pos;
 385         int head_need;
 386
 387         if (unlikely(skb->len < ETH_HLEN))
 388                 return -EINVAL;
 389
 390         nh_pos = skb_network_header(skb) - skb->data;
 391         h_pos = skb_transport_header(skb) - skb->data;
 392
 393         /* convert Ethernet header to proper 802.11 header (based on
 394          * operation mode) */
 395         ethertype = (skb->data[12] << 8) | skb->data[13];
 396         fc = cpu_to_le16(IEEE80211_FTYPE_DATA | IEEE80211_STYPE_DATA);
 397
 398         switch (iftype) {
 399         case NL80211_IFTYPE_AP:
 400         case NL80211_IFTYPE_AP_VLAN:
 401                 fc |= cpu_to_le16(IEEE80211_FCTL_FROMDS);
 402                 /* DA BSSID SA */
 403                 memcpy(hdr.addr1, skb->data, ETH_ALEN);
 404                 memcpy(hdr.addr2, addr, ETH_ALEN);
 405                 memcpy(hdr.addr3, skb->data + ETH_ALEN, ETH_ALEN);
 406                 hdrlen = 24;
 407                 break;
 408         case NL80211_IFTYPE_STATION:
 409                 fc |= cpu_to_le16(IEEE80211_FCTL_TODS);
 410                 /* BSSID SA DA */
 411                 memcpy(hdr.addr1, bssid, ETH_ALEN);
 412                 memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
 413                 memcpy(hdr.addr3, skb->data, ETH_ALEN);
 414                 hdrlen = 24;
 415                 break;
 416         case NL80211_IFTYPE_ADHOC:
 417                 /* DA SA BSSID */
 418                 memcpy(hdr.addr1, skb->data, ETH_ALEN);
 419                 memcpy(hdr.addr2, skb->data + ETH_ALEN, ETH_ALEN);
 420                 memcpy(hdr.addr3, bssid, ETH_ALEN);
 421                 hdrlen = 24;
 422                 break;
 423         default:
 424                 return -EOPNOTSUPP;
 425         }
 426
 427         if (qos) {
 428                 fc |= cpu_to_le16(IEEE80211_STYPE_QOS_DATA);
 429                 hdrlen += 2;
 430         }
 431
 432         hdr.frame_control = fc;
 433         hdr.duration_id = 0;
 434         hdr.seq_ctrl = 0;
 435
 436         skip_header_bytes = ETH_HLEN;
 437         if (ethertype == ETH_P_AARP || ethertype == ETH_P_IPX) {
 438                 encaps_data = bridge_tunnel_header;
 439                 encaps_len = sizeof(bridge_tunnel_header);
 440                 skip_header_bytes -= 2;
 441         } else if (ethertype > 0x600) {
 442                 encaps_data = rfc1042_header;
 443                 encaps_len = sizeof(rfc1042_header);
 444                 skip_header_bytes -= 2;
 445         } else {
 446                 encaps_data = NULL;
 447                 encaps_len = 0;
 448         }
 449
 450         skb_pull(skb, skip_header_bytes);
 451         nh_pos -= skip_header_bytes;
 452         h_pos -= skip_header_bytes;
 453
 454         head_need = hdrlen + encaps_len - skb_headroom(skb);
 455
 456         if (head_need > 0 || skb_cloned(skb)) {
 457                 head_need = max(head_need, 0);
 458                 if (head_need)
 459                         skb_orphan(skb);
 460
 461                 if (pskb_expand_head(skb, head_need, 0, GFP_ATOMIC)) {
 462                         printk(KERN_ERR "failed to reallocate Tx buffer\n");
 463                         return -ENOMEM;
 464                 }
 465                 skb->truesize += head_need;
 466         }
 467
 468         if (encaps_data) {
 469                 memcpy(skb_push(skb, encaps_len), encaps_data, encaps_len);
 470                 nh_pos += encaps_len;
 471                 h_pos += encaps_len;
 472         }
 473
 474         memcpy(skb_push(skb, hdrlen), &hdr, hdrlen);
 475
 476         nh_pos += hdrlen;
 477         h_pos += hdrlen;
 478
 479         /* Update skb pointers to various headers since this modified frame
 480          * is going to go through Linux networking code that may potentially
 481          * need things like pointer to IP header. */
 482         skb_set_mac_header(skb, 0);
 483         skb_set_network_header(skb, nh_pos);
 484         skb_set_transport_header(skb, h_pos);
 485
 486         return 0;
 487 }
 488 EXPORT_SYMBOL(ieee80211_data_from_8023);
 489
 490 /* Given a data frame determine the 802.1p/1d tag to use. */
 491 unsigned int cfg80211_classify8021d(struct sk_buff *skb)
 492 {
 493         unsigned int dscp;
 494
 495         /* skb->priority values from 256->263 are magic values to
 496          * directly indicate a specific 802.1d priority.  This is used
 497          * to allow 802.1d priority to be passed directly in from VLAN
 498          * tags, etc.
 499          */
 500         if (skb->priority >= 256 && skb->priority <= 263)
 501                 return skb->priority - 256;
 502
 503         switch (skb->protocol) {
 504         case htons(ETH_P_IP):
 505                 dscp = ip_hdr(skb)->tos & 0xfc;
 506                 break;
 507         default:
 508                 return 0;
 509         }
 510
 511         return dscp >> 5;
 512 }
 513 EXPORT_SYMBOL(cfg80211_classify8021d);
 514
 515 const u8 *ieee80211_bss_get_ie(struct cfg80211_bss *bss, u8 ie)
 516 {
 517         u8 *end, *pos;
 518
 519         pos = bss->information_elements;
 520         if (pos == NULL)
 521                 return NULL;
 522         end = pos + bss->len_information_elements;
 523
 524         while (pos + 1 < end) {
 525                 if (pos + 2 + pos[1] > end)
 526                         break;
 527                 if (pos[0] == ie)
 528                         return pos;
 529                 pos += 2 + pos[1];
 530         }
 531
 532         return NULL;
 533 }
 534 EXPORT_SYMBOL(ieee80211_bss_get_ie);
 535
 536 void cfg80211_upload_connect_keys(struct wireless_dev *wdev)
 537 {
 538         struct cfg80211_registered_device *rdev = wiphy_to_dev(wdev->wiphy);
 539         struct net_device *dev = wdev->netdev;
 540         int i;
 541
 542         if (!wdev->connect_keys)
 543                 return;
 544
 545         for (i = 0; i < 6; i++) {
 546                 if (!wdev->connect_keys->params[i].cipher)
 547                         continue;
 548                 if (rdev->ops->add_key(wdev->wiphy, dev, i, NULL,
 549                                         &wdev->connect_keys->params[i])) {
 550                         printk(KERN_ERR "%s: failed to set key %d\n",
 551                                 dev->name, i);
 552                         continue;
 553                 }
 554                 if (wdev->connect_keys->def == i)
 555                         if (rdev->ops->set_default_key(wdev->wiphy, dev, i)) {
 556                                 printk(KERN_ERR "%s: failed to set defkey %d\n",
 557                                         dev->name, i);
 558                                 continue;
 559                         }
 560                 if (wdev->connect_keys->defmgmt == i)
 561                         if (rdev->ops->set_default_mgmt_key(wdev->wiphy, dev, i))
 562                                 printk(KERN_ERR "%s: failed to set mgtdef %d\n",
 563                                         dev->name, i);
 564         }
 565
 566         kfree(wdev->connect_keys);
 567         wdev->connect_keys = NULL;
 568 }