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