src/ap/beacon.c

   1 /*
   2  * hostapd / IEEE 802.11 Management: Beacon and Probe Request/Response
   3  * Copyright (c) 2002-2004, Instant802 Networks, Inc.
   4  * Copyright (c) 2005-2006, Devicescape Software, Inc.
   5  * Copyright (c) 2008-2009, Jouni Malinen <j@w1.fi>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * Alternatively, this software may be distributed under the terms of BSD
  12  * license.
  13  *
  14  * See README and COPYING for more details.
  15  */
  16
  17 #include "utils/includes.h"
  18
  19 #ifndef CONFIG_NATIVE_WINDOWS
  20
  21 #include "utils/common.h"
  22 #include "common/ieee802_11_defs.h"
  23 #include "common/ieee802_11_common.h"
  24 #include "drivers/driver.h"
  25 #include "wps/wps_defs.h"
  26 #include "p2p/p2p.h"
  27 #include "hostapd.h"
  28 #include "ieee802_11.h"
  29 #include "wpa_auth.h"
  30 #include "wmm.h"
  31 #include "ap_config.h"
  32 #include "sta_info.h"
  33 #include "beacon.h"
  34
  35
  36 static u8 ieee802_11_erp_info(struct hostapd_data *hapd)
  37 {
  38         u8 erp = 0;
  39
  40         if (hapd->iface->current_mode == NULL ||
  41             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  42                 return 0;
  43
  44         switch (hapd->iconf->cts_protection_type) {
  45         case CTS_PROTECTION_FORCE_ENABLED:
  46                 erp |= ERP_INFO_NON_ERP_PRESENT | ERP_INFO_USE_PROTECTION;
  47                 break;
  48         case CTS_PROTECTION_FORCE_DISABLED:
  49                 erp = 0;
  50                 break;
  51         case CTS_PROTECTION_AUTOMATIC:
  52                 if (hapd->iface->olbc)
  53                         erp |= ERP_INFO_USE_PROTECTION;
  54                 /* continue */
  55         case CTS_PROTECTION_AUTOMATIC_NO_OLBC:
  56                 if (hapd->iface->num_sta_non_erp > 0) {
  57                         erp |= ERP_INFO_NON_ERP_PRESENT |
  58                                 ERP_INFO_USE_PROTECTION;
  59                 }
  60                 break;
  61         }
  62         if (hapd->iface->num_sta_no_short_preamble > 0 ||
  63             hapd->iconf->preamble == LONG_PREAMBLE)
  64                 erp |= ERP_INFO_BARKER_PREAMBLE_MODE;
  65
  66         return erp;
  67 }
  68
  69
  70 static u8 * hostapd_eid_ds_params(struct hostapd_data *hapd, u8 *eid)
  71 {
  72         *eid++ = WLAN_EID_DS_PARAMS;
  73         *eid++ = 1;
  74         *eid++ = hapd->iconf->channel;
  75         return eid;
  76 }
  77
  78
  79 static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
  80 {
  81         if (hapd->iface->current_mode == NULL ||
  82             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  83                 return eid;
  84
  85         /* Set NonERP_present and use_protection bits if there
  86          * are any associated NonERP stations. */
  87         /* TODO: use_protection bit can be set to zero even if
  88          * there are NonERP stations present. This optimization
  89          * might be useful if NonERP stations are "quiet".
  90          * See 802.11g/D6 E-1 for recommended practice.
  91          * In addition, Non ERP present might be set, if AP detects Non ERP
  92          * operation on other APs. */
  93
  94         /* Add ERP Information element */
  95         *eid++ = WLAN_EID_ERP_INFO;
  96         *eid++ = 1;
  97         *eid++ = ieee802_11_erp_info(hapd);
  98
  99         return eid;
 100 }
 101
 102
 103 static u8 * hostapd_eid_country_add(u8 *pos, u8 *end, int chan_spacing,
 104                                     struct hostapd_channel_data *start,
 105                                     struct hostapd_channel_data *prev)
 106 {
 107         if (end - pos < 3)
 108                 return pos;
 109
 110         /* first channel number */
 111         *pos++ = start->chan;
 112         /* number of channels */
 113         *pos++ = (prev->chan - start->chan) / chan_spacing + 1;
 114         /* maximum transmit power level */
 115         *pos++ = start->max_tx_power;
 116
 117         return pos;
 118 }
 119
 120
 121 static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
 122                                 int max_len)
 123 {
 124         u8 *pos = eid;
 125         u8 *end = eid + max_len;
 126         int i;
 127         struct hostapd_hw_modes *mode;
 128         struct hostapd_channel_data *start, *prev;
 129         int chan_spacing = 1;
 130
 131         if (!hapd->iconf->ieee80211d || max_len < 6 ||
 132             hapd->iface->current_mode == NULL)
 133                 return eid;
 134
 135         *pos++ = WLAN_EID_COUNTRY;
 136         pos++; /* length will be set later */
 137         os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
 138         pos += 3;
 139
 140         mode = hapd->iface->current_mode;
 141         if (mode->mode == HOSTAPD_MODE_IEEE80211A)
 142                 chan_spacing = 4;
 143
 144         start = prev = NULL;
 145         for (i = 0; i < mode->num_channels; i++) {
 146                 struct hostapd_channel_data *chan = &mode->channels[i];
 147                 if (chan->flag & HOSTAPD_CHAN_DISABLED)
 148                         continue;
 149                 if (start && prev &&
 150                     prev->chan + chan_spacing == chan->chan &&
 151                     start->max_tx_power == chan->max_tx_power) {
 152                         prev = chan;
 153                         continue; /* can use same entry */
 154                 }
 155
 156                 if (start) {
 157                         pos = hostapd_eid_country_add(pos, end, chan_spacing,
 158                                                       start, prev);
 159                         start = NULL;
 160                 }
 161
 162                 /* Start new group */
 163                 start = prev = chan;
 164         }
 165
 166         if (start) {
 167                 pos = hostapd_eid_country_add(pos, end, chan_spacing,
 168                                               start, prev);
 169         }
 170
 171         if ((pos - eid) & 1) {
 172                 if (end - pos < 1)
 173                         return eid;
 174                 *pos++ = 0; /* pad for 16-bit alignment */
 175         }
 176
 177         eid[1] = (pos - eid) - 2;
 178
 179         return pos;
 180 }
 181
 182
 183 static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
 184                             struct sta_info *sta)
 185 {
 186         const u8 *ie;
 187         size_t ielen;
 188
 189         ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
 190         if (ie == NULL || ielen > len)
 191                 return eid;
 192
 193         os_memcpy(eid, ie, ielen);
 194         return eid + ielen;
 195 }
 196
 197
 198 void handle_probe_req(struct hostapd_data *hapd,
 199                       const struct ieee80211_mgmt *mgmt, size_t len)
 200 {
 201         struct ieee80211_mgmt *resp;
 202         struct ieee802_11_elems elems;
 203         char *ssid;
 204         u8 *pos, *epos;
 205         const u8 *ie;
 206         size_t ssid_len, ie_len;
 207         struct sta_info *sta = NULL;
 208         size_t buflen;
 209         size_t i;
 210
 211         ie = mgmt->u.probe_req.variable;
 212         ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
 213
 214         for (i = 0; hapd->probereq_cb && i < hapd->num_probereq_cb; i++)
 215                 if (hapd->probereq_cb[i].cb(hapd->probereq_cb[i].ctx,
 216                                             mgmt->sa, ie, ie_len) > 0)
 217                         return;
 218
 219         if (!hapd->iconf->send_probe_response)
 220                 return;
 221
 222         if (ieee802_11_parse_elems(ie, ie_len, &elems, 0) == ParseFailed) {
 223                 wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
 224                            MAC2STR(mgmt->sa));
 225                 return;
 226         }
 227
 228         ssid = NULL;
 229         ssid_len = 0;
 230
 231         if ((!elems.ssid || !elems.supp_rates)) {
 232                 wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
 233                            "without SSID or supported rates element",
 234                            MAC2STR(mgmt->sa));
 235                 return;
 236         }
 237
 238 #ifdef CONFIG_P2P
 239         if (hapd->p2p && elems.wps_ie) {
 240                 struct wpabuf *wps;
 241                 wps = ieee802_11_vendor_ie_concat(ie, ie_len, WPS_DEV_OUI_WFA);
 242                 if (wps && !p2p_group_match_dev_type(hapd->p2p_group, wps)) {
 243                         wpa_printf(MSG_MSGDUMP, "P2P: Ignore Probe Request "
 244                                    "due to mismatch with Requested Device "
 245                                    "Type");
 246                         wpabuf_free(wps);
 247                         return;
 248                 }
 249                 wpabuf_free(wps);
 250         }
 251 #endif /* CONFIG_P2P */
 252
 253         if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
 254                 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
 255                            "broadcast SSID ignored", MAC2STR(mgmt->sa));
 256                 return;
 257         }
 258
 259         sta = ap_get_sta(hapd, mgmt->sa);
 260
 261 #ifdef CONFIG_P2P
 262         if ((hapd->conf->p2p & P2P_GROUP_OWNER) &&
 263             elems.ssid_len == P2P_WILDCARD_SSID_LEN &&
 264             os_memcmp(elems.ssid, P2P_WILDCARD_SSID,
 265                       P2P_WILDCARD_SSID_LEN) == 0) {
 266                 /* Process P2P Wildcard SSID like Wildcard SSID */
 267                 elems.ssid_len = 0;
 268         }
 269 #endif /* CONFIG_P2P */
 270
 271         if (elems.ssid_len == 0 ||
 272             (elems.ssid_len == hapd->conf->ssid.ssid_len &&
 273              os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
 274              0)) {
 275                 ssid = hapd->conf->ssid.ssid;
 276                 ssid_len = hapd->conf->ssid.ssid_len;
 277                 if (sta)
 278                         sta->ssid_probe = &hapd->conf->ssid;
 279         }
 280
 281         if (!ssid) {
 282                 if (!(mgmt->da[0] & 0x01)) {
 283                         char ssid_txt[33];
 284                         ieee802_11_print_ssid(ssid_txt, elems.ssid,
 285                                               elems.ssid_len);
 286                         wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
 287                                    " for foreign SSID '%s' (DA " MACSTR ")",
 288                                    MAC2STR(mgmt->sa), ssid_txt,
 289                                    MAC2STR(mgmt->da));
 290                 }
 291                 return;
 292         }
 293
 294         /* TODO: verify that supp_rates contains at least one matching rate
 295          * with AP configuration */
 296 #define MAX_PROBERESP_LEN 768
 297         buflen = MAX_PROBERESP_LEN;
 298 #ifdef CONFIG_WPS
 299         if (hapd->wps_probe_resp_ie)
 300                 buflen += wpabuf_len(hapd->wps_probe_resp_ie);
 301 #endif /* CONFIG_WPS */
 302 #ifdef CONFIG_P2P
 303         if (hapd->p2p_probe_resp_ie)
 304                 buflen += wpabuf_len(hapd->p2p_probe_resp_ie);
 305 #endif /* CONFIG_P2P */
 306         resp = os_zalloc(buflen);
 307         if (resp == NULL)
 308                 return;
 309         epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
 310
 311         resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 312                                            WLAN_FC_STYPE_PROBE_RESP);
 313         os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
 314         os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
 315
 316         os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
 317         resp->u.probe_resp.beacon_int =
 318                 host_to_le16(hapd->iconf->beacon_int);
 319
 320         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 321         resp->u.probe_resp.capab_info =
 322                 host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
 323
 324         pos = resp->u.probe_resp.variable;
 325         *pos++ = WLAN_EID_SSID;
 326         *pos++ = ssid_len;
 327         os_memcpy(pos, ssid, ssid_len);
 328         pos += ssid_len;
 329
 330         /* Supported rates */
 331         pos = hostapd_eid_supp_rates(hapd, pos);
 332
 333         /* DS Params */
 334         pos = hostapd_eid_ds_params(hapd, pos);
 335
 336         pos = hostapd_eid_country(hapd, pos, epos - pos);
 337
 338         /* ERP Information element */
 339         pos = hostapd_eid_erp_info(hapd, pos);
 340
 341         /* Extended supported rates */
 342         pos = hostapd_eid_ext_supp_rates(hapd, pos);
 343
 344         /* RSN, MDIE, WPA */
 345         pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
 346
 347 #ifdef CONFIG_IEEE80211N
 348         pos = hostapd_eid_ht_capabilities(hapd, pos);
 349         pos = hostapd_eid_ht_operation(hapd, pos);
 350 #endif /* CONFIG_IEEE80211N */
 351
 352         /* Wi-Fi Alliance WMM */
 353         pos = hostapd_eid_wmm(hapd, pos);
 354
 355 #ifdef CONFIG_WPS
 356         if (hapd->conf->wps_state && hapd->wps_probe_resp_ie) {
 357                 os_memcpy(pos, wpabuf_head(hapd->wps_probe_resp_ie),
 358                           wpabuf_len(hapd->wps_probe_resp_ie));
 359                 pos += wpabuf_len(hapd->wps_probe_resp_ie);
 360         }
 361 #endif /* CONFIG_WPS */
 362
 363 #ifdef CONFIG_P2P
 364         if ((hapd->conf->p2p & P2P_ENABLED) && elems.p2p &&
 365             hapd->p2p_probe_resp_ie) {
 366                 os_memcpy(pos, wpabuf_head(hapd->p2p_probe_resp_ie),
 367                           wpabuf_len(hapd->p2p_probe_resp_ie));
 368                 pos += wpabuf_len(hapd->p2p_probe_resp_ie);
 369         }
 370 #endif /* CONFIG_P2P */
 371
 372         if (hapd->drv.send_mgmt_frame(hapd, resp, pos - (u8 *) resp) < 0)
 373                 perror("handle_probe_req: send");
 374
 375         os_free(resp);
 376
 377         wpa_printf(MSG_EXCESSIVE, "STA " MACSTR " sent probe request for %s "
 378                    "SSID", MAC2STR(mgmt->sa),
 379                    elems.ssid_len == 0 ? "broadcast" : "our");
 380 }
 381
 382
 383 void ieee802_11_set_beacon(struct hostapd_data *hapd)
 384 {
 385         struct ieee80211_mgmt *head;
 386         u8 *pos, *tail, *tailpos;
 387         u16 capab_info;
 388         size_t head_len, tail_len;
 389
 390 #ifdef CONFIG_P2P
 391         if ((hapd->conf->p2p & (P2P_ENABLED | P2P_GROUP_OWNER)) == P2P_ENABLED)
 392                 goto no_beacon;
 393 #endif /* CONFIG_P2P */
 394
 395 #define BEACON_HEAD_BUF_SIZE 256
 396 #define BEACON_TAIL_BUF_SIZE 512
 397         head = os_zalloc(BEACON_HEAD_BUF_SIZE);
 398         tail_len = BEACON_TAIL_BUF_SIZE;
 399 #ifdef CONFIG_WPS
 400         if (hapd->conf->wps_state && hapd->wps_beacon_ie)
 401                 tail_len += wpabuf_len(hapd->wps_beacon_ie);
 402 #endif /* CONFIG_WPS */
 403 #ifdef CONFIG_P2P
 404         if (hapd->p2p_beacon_ie)
 405                 tail_len += wpabuf_len(hapd->p2p_beacon_ie);
 406 #endif /* CONFIG_P2P */
 407         tailpos = tail = os_malloc(tail_len);
 408         if (head == NULL || tail == NULL) {
 409                 wpa_printf(MSG_ERROR, "Failed to set beacon data");
 410                 os_free(head);
 411                 os_free(tail);
 412                 return;
 413         }
 414
 415         head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 416                                            WLAN_FC_STYPE_BEACON);
 417         head->duration = host_to_le16(0);
 418         os_memset(head->da, 0xff, ETH_ALEN);
 419
 420         os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
 421         os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
 422         head->u.beacon.beacon_int =
 423                 host_to_le16(hapd->iconf->beacon_int);
 424
 425         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 426         capab_info = hostapd_own_capab_info(hapd, NULL, 0);
 427         head->u.beacon.capab_info = host_to_le16(capab_info);
 428         pos = &head->u.beacon.variable[0];
 429
 430         /* SSID */
 431         *pos++ = WLAN_EID_SSID;
 432         if (hapd->conf->ignore_broadcast_ssid == 2) {
 433                 /* clear the data, but keep the correct length of the SSID */
 434                 *pos++ = hapd->conf->ssid.ssid_len;
 435                 os_memset(pos, 0, hapd->conf->ssid.ssid_len);
 436                 pos += hapd->conf->ssid.ssid_len;
 437         } else if (hapd->conf->ignore_broadcast_ssid) {
 438                 *pos++ = 0; /* empty SSID */
 439         } else {
 440                 *pos++ = hapd->conf->ssid.ssid_len;
 441                 os_memcpy(pos, hapd->conf->ssid.ssid,
 442                           hapd->conf->ssid.ssid_len);
 443                 pos += hapd->conf->ssid.ssid_len;
 444         }
 445
 446         /* Supported rates */
 447         pos = hostapd_eid_supp_rates(hapd, pos);
 448
 449         /* DS Params */
 450         pos = hostapd_eid_ds_params(hapd, pos);
 451
 452         head_len = pos - (u8 *) head;
 453
 454         tailpos = hostapd_eid_country(hapd, tailpos,
 455                                       tail + BEACON_TAIL_BUF_SIZE - tailpos);
 456
 457         /* ERP Information element */
 458         tailpos = hostapd_eid_erp_info(hapd, tailpos);
 459
 460         /* Extended supported rates */
 461         tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
 462
 463         /* RSN, MDIE, WPA */
 464         tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
 465                                   tailpos, NULL);
 466
 467 #ifdef CONFIG_IEEE80211N
 468         tailpos = hostapd_eid_ht_capabilities(hapd, tailpos);
 469         tailpos = hostapd_eid_ht_operation(hapd, tailpos);
 470 #endif /* CONFIG_IEEE80211N */
 471
 472         /* Wi-Fi Alliance WMM */
 473         tailpos = hostapd_eid_wmm(hapd, tailpos);
 474
 475 #ifdef CONFIG_WPS
 476         if (hapd->conf->wps_state && hapd->wps_beacon_ie) {
 477                 os_memcpy(tailpos, wpabuf_head(hapd->wps_beacon_ie),
 478                           wpabuf_len(hapd->wps_beacon_ie));
 479                 tailpos += wpabuf_len(hapd->wps_beacon_ie);
 480         }
 481 #endif /* CONFIG_WPS */
 482
 483 #ifdef CONFIG_P2P
 484         if ((hapd->conf->p2p & P2P_ENABLED) && hapd->p2p_beacon_ie) {
 485                 os_memcpy(tailpos, wpabuf_head(hapd->p2p_beacon_ie),
 486                           wpabuf_len(hapd->p2p_beacon_ie));
 487                 tailpos += wpabuf_len(hapd->p2p_beacon_ie);
 488         }
 489 #endif /* CONFIG_P2P */
 490
 491         tail_len = tailpos > tail ? tailpos - tail : 0;
 492
 493         if (hapd->drv.set_beacon(hapd, (u8 *) head, head_len,
 494                                  tail, tail_len, hapd->conf->dtim_period,
 495                                  hapd->iconf->beacon_int))
 496                 wpa_printf(MSG_ERROR, "Failed to set beacon head/tail or DTIM "
 497                            "period");
 498
 499         os_free(tail);
 500         os_free(head);
 501
 502 #ifdef CONFIG_P2P
 503 no_beacon:
 504 #endif /* CONFIG_P2P */
 505         hapd->drv.set_bss_params(hapd, !!(ieee802_11_erp_info(hapd) &
 506                                           ERP_INFO_USE_PROTECTION));
 507 }
 508
 509
 510 void ieee802_11_set_beacons(struct hostapd_iface *iface)
 511 {
 512         size_t i;
 513         for (i = 0; i < iface->num_bss; i++)
 514                 ieee802_11_set_beacon(iface->bss[i]);
 515 }
 516
 517 #endif /* CONFIG_NATIVE_WINDOWS */