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 "p2p_hostapd.h"
  34 #include "ap_drv_ops.h"
  35 #include "beacon.h"
  36
  37
  38 static u8 ieee802_11_erp_info(struct hostapd_data *hapd)
  39 {
  40         u8 erp = 0;
  41
  42         if (hapd->iface->current_mode == NULL ||
  43             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  44                 return 0;
  45
  46         switch (hapd->iconf->cts_protection_type) {
  47         case CTS_PROTECTION_FORCE_ENABLED:
  48                 erp |= ERP_INFO_NON_ERP_PRESENT | ERP_INFO_USE_PROTECTION;
  49                 break;
  50         case CTS_PROTECTION_FORCE_DISABLED:
  51                 erp = 0;
  52                 break;
  53         case CTS_PROTECTION_AUTOMATIC:
  54                 if (hapd->iface->olbc)
  55                         erp |= ERP_INFO_USE_PROTECTION;
  56                 /* continue */
  57         case CTS_PROTECTION_AUTOMATIC_NO_OLBC:
  58                 if (hapd->iface->num_sta_non_erp > 0) {
  59                         erp |= ERP_INFO_NON_ERP_PRESENT |
  60                                 ERP_INFO_USE_PROTECTION;
  61                 }
  62                 break;
  63         }
  64         if (hapd->iface->num_sta_no_short_preamble > 0 ||
  65             hapd->iconf->preamble == LONG_PREAMBLE)
  66                 erp |= ERP_INFO_BARKER_PREAMBLE_MODE;
  67
  68         return erp;
  69 }
  70
  71
  72 static u8 * hostapd_eid_ds_params(struct hostapd_data *hapd, u8 *eid)
  73 {
  74         *eid++ = WLAN_EID_DS_PARAMS;
  75         *eid++ = 1;
  76         *eid++ = hapd->iconf->channel;
  77         return eid;
  78 }
  79
  80
  81 static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
  82 {
  83         if (hapd->iface->current_mode == NULL ||
  84             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  85                 return eid;
  86
  87         /* Set NonERP_present and use_protection bits if there
  88          * are any associated NonERP stations. */
  89         /* TODO: use_protection bit can be set to zero even if
  90          * there are NonERP stations present. This optimization
  91          * might be useful if NonERP stations are "quiet".
  92          * See 802.11g/D6 E-1 for recommended practice.
  93          * In addition, Non ERP present might be set, if AP detects Non ERP
  94          * operation on other APs. */
  95
  96         /* Add ERP Information element */
  97         *eid++ = WLAN_EID_ERP_INFO;
  98         *eid++ = 1;
  99         *eid++ = ieee802_11_erp_info(hapd);
 100
 101         return eid;
 102 }
 103
 104
 105 static u8 * hostapd_eid_country_add(u8 *pos, u8 *end, int chan_spacing,
 106                                     struct hostapd_channel_data *start,
 107                                     struct hostapd_channel_data *prev)
 108 {
 109         if (end - pos < 3)
 110                 return pos;
 111
 112         /* first channel number */
 113         *pos++ = start->chan;
 114         /* number of channels */
 115         *pos++ = (prev->chan - start->chan) / chan_spacing + 1;
 116         /* maximum transmit power level */
 117         *pos++ = start->max_tx_power;
 118
 119         return pos;
 120 }
 121
 122
 123 static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
 124                                 int max_len)
 125 {
 126         u8 *pos = eid;
 127         u8 *end = eid + max_len;
 128         int i;
 129         struct hostapd_hw_modes *mode;
 130         struct hostapd_channel_data *start, *prev;
 131         int chan_spacing = 1;
 132
 133         if (!hapd->iconf->ieee80211d || max_len < 6 ||
 134             hapd->iface->current_mode == NULL)
 135                 return eid;
 136
 137         *pos++ = WLAN_EID_COUNTRY;
 138         pos++; /* length will be set later */
 139         os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
 140         pos += 3;
 141
 142         mode = hapd->iface->current_mode;
 143         if (mode->mode == HOSTAPD_MODE_IEEE80211A)
 144                 chan_spacing = 4;
 145
 146         start = prev = NULL;
 147         for (i = 0; i < mode->num_channels; i++) {
 148                 struct hostapd_channel_data *chan = &mode->channels[i];
 149                 if (chan->flag & HOSTAPD_CHAN_DISABLED)
 150                         continue;
 151                 if (start && prev &&
 152                     prev->chan + chan_spacing == chan->chan &&
 153                     start->max_tx_power == chan->max_tx_power) {
 154                         prev = chan;
 155                         continue; /* can use same entry */
 156                 }
 157
 158                 if (start) {
 159                         pos = hostapd_eid_country_add(pos, end, chan_spacing,
 160                                                       start, prev);
 161                         start = NULL;
 162                 }
 163
 164                 /* Start new group */
 165                 start = prev = chan;
 166         }
 167
 168         if (start) {
 169                 pos = hostapd_eid_country_add(pos, end, chan_spacing,
 170                                               start, prev);
 171         }
 172
 173         if ((pos - eid) & 1) {
 174                 if (end - pos < 1)
 175                         return eid;
 176                 *pos++ = 0; /* pad for 16-bit alignment */
 177         }
 178
 179         eid[1] = (pos - eid) - 2;
 180
 181         return pos;
 182 }
 183
 184
 185 static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
 186                             struct sta_info *sta)
 187 {
 188         const u8 *ie;
 189         size_t ielen;
 190
 191         ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
 192         if (ie == NULL || ielen > len)
 193                 return eid;
 194
 195         os_memcpy(eid, ie, ielen);
 196         return eid + ielen;
 197 }
 198
 199
 200 void handle_probe_req(struct hostapd_data *hapd,
 201                       const struct ieee80211_mgmt *mgmt, size_t len)
 202 {
 203         struct ieee80211_mgmt *resp;
 204         struct ieee802_11_elems elems;
 205         char *ssid;
 206         u8 *pos, *epos;
 207         const u8 *ie;
 208         size_t ssid_len, ie_len;
 209         struct sta_info *sta = NULL;
 210         size_t buflen;
 211         size_t i;
 212
 213         ie = mgmt->u.probe_req.variable;
 214         ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
 215
 216         for (i = 0; hapd->probereq_cb && i < hapd->num_probereq_cb; i++)
 217                 if (hapd->probereq_cb[i].cb(hapd->probereq_cb[i].ctx,
 218                                             mgmt->sa, ie, ie_len) > 0)
 219                         return;
 220
 221         if (!hapd->iconf->send_probe_response)
 222                 return;
 223
 224         if (ieee802_11_parse_elems(ie, ie_len, &elems, 0) == ParseFailed) {
 225                 wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
 226                            MAC2STR(mgmt->sa));
 227                 return;
 228         }
 229
 230         ssid = NULL;
 231         ssid_len = 0;
 232
 233         if ((!elems.ssid || !elems.supp_rates)) {
 234                 wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
 235                            "without SSID or supported rates element",
 236                            MAC2STR(mgmt->sa));
 237                 return;
 238         }
 239
 240 #ifdef CONFIG_P2P
 241         if (hapd->p2p && elems.wps_ie) {
 242                 struct wpabuf *wps;
 243                 wps = ieee802_11_vendor_ie_concat(ie, ie_len, WPS_DEV_OUI_WFA);
 244                 if (wps && !p2p_group_match_dev_type(hapd->p2p_group, wps)) {
 245                         wpa_printf(MSG_MSGDUMP, "P2P: Ignore Probe Request "
 246                                    "due to mismatch with Requested Device "
 247                                    "Type");
 248                         wpabuf_free(wps);
 249                         return;
 250                 }
 251                 wpabuf_free(wps);
 252         }
 253 #endif /* CONFIG_P2P */
 254
 255         if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
 256                 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
 257                            "broadcast SSID ignored", MAC2STR(mgmt->sa));
 258                 return;
 259         }
 260
 261         sta = ap_get_sta(hapd, mgmt->sa);
 262
 263 #ifdef CONFIG_P2P
 264         if ((hapd->conf->p2p & P2P_GROUP_OWNER) &&
 265             elems.ssid_len == P2P_WILDCARD_SSID_LEN &&
 266             os_memcmp(elems.ssid, P2P_WILDCARD_SSID,
 267                       P2P_WILDCARD_SSID_LEN) == 0) {
 268                 /* Process P2P Wildcard SSID like Wildcard SSID */
 269                 elems.ssid_len = 0;
 270         }
 271 #endif /* CONFIG_P2P */
 272
 273         if (elems.ssid_len == 0 ||
 274             (elems.ssid_len == hapd->conf->ssid.ssid_len &&
 275              os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
 276              0)) {
 277                 ssid = hapd->conf->ssid.ssid;
 278                 ssid_len = hapd->conf->ssid.ssid_len;
 279                 if (sta)
 280                         sta->ssid_probe = &hapd->conf->ssid;
 281         }
 282
 283         if (!ssid) {
 284                 if (!(mgmt->da[0] & 0x01)) {
 285                         char ssid_txt[33];
 286                         ieee802_11_print_ssid(ssid_txt, elems.ssid,
 287                                               elems.ssid_len);
 288                         wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
 289                                    " for foreign SSID '%s' (DA " MACSTR ")",
 290                                    MAC2STR(mgmt->sa), ssid_txt,
 291                                    MAC2STR(mgmt->da));
 292                 }
 293                 return;
 294         }
 295
 296         /* TODO: verify that supp_rates contains at least one matching rate
 297          * with AP configuration */
 298 #define MAX_PROBERESP_LEN 768
 299         buflen = MAX_PROBERESP_LEN;
 300 #ifdef CONFIG_WPS
 301         if (hapd->wps_probe_resp_ie)
 302                 buflen += wpabuf_len(hapd->wps_probe_resp_ie);
 303 #endif /* CONFIG_WPS */
 304 #ifdef CONFIG_P2P
 305         if (hapd->p2p_probe_resp_ie)
 306                 buflen += wpabuf_len(hapd->p2p_probe_resp_ie);
 307 #endif /* CONFIG_P2P */
 308         resp = os_zalloc(buflen);
 309         if (resp == NULL)
 310                 return;
 311         epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
 312
 313         resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 314                                            WLAN_FC_STYPE_PROBE_RESP);
 315         os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
 316         os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
 317
 318         os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
 319         resp->u.probe_resp.beacon_int =
 320                 host_to_le16(hapd->iconf->beacon_int);
 321
 322         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 323         resp->u.probe_resp.capab_info =
 324                 host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
 325
 326         pos = resp->u.probe_resp.variable;
 327         *pos++ = WLAN_EID_SSID;
 328         *pos++ = ssid_len;
 329         os_memcpy(pos, ssid, ssid_len);
 330         pos += ssid_len;
 331
 332         /* Supported rates */
 333         pos = hostapd_eid_supp_rates(hapd, pos);
 334
 335         /* DS Params */
 336         pos = hostapd_eid_ds_params(hapd, pos);
 337
 338         pos = hostapd_eid_country(hapd, pos, epos - pos);
 339
 340         /* ERP Information element */
 341         pos = hostapd_eid_erp_info(hapd, pos);
 342
 343         /* Extended supported rates */
 344         pos = hostapd_eid_ext_supp_rates(hapd, pos);
 345
 346         /* RSN, MDIE, WPA */
 347         pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
 348
 349 #ifdef CONFIG_IEEE80211N
 350         pos = hostapd_eid_ht_capabilities(hapd, pos);
 351         pos = hostapd_eid_ht_operation(hapd, pos);
 352 #endif /* CONFIG_IEEE80211N */
 353
 354         /* Wi-Fi Alliance WMM */
 355         pos = hostapd_eid_wmm(hapd, pos);
 356
 357 #ifdef CONFIG_WPS
 358         if (hapd->conf->wps_state && hapd->wps_probe_resp_ie) {
 359                 os_memcpy(pos, wpabuf_head(hapd->wps_probe_resp_ie),
 360                           wpabuf_len(hapd->wps_probe_resp_ie));
 361                 pos += wpabuf_len(hapd->wps_probe_resp_ie);
 362         }
 363 #endif /* CONFIG_WPS */
 364
 365 #ifdef CONFIG_P2P
 366         if ((hapd->conf->p2p & P2P_ENABLED) && elems.p2p &&
 367             hapd->p2p_probe_resp_ie) {
 368                 os_memcpy(pos, wpabuf_head(hapd->p2p_probe_resp_ie),
 369                           wpabuf_len(hapd->p2p_probe_resp_ie));
 370                 pos += wpabuf_len(hapd->p2p_probe_resp_ie);
 371         }
 372 #endif /* CONFIG_P2P */
 373 #ifdef CONFIG_P2P_MANAGER
 374         if ((hapd->conf->p2p & (P2P_MANAGE | P2P_ENABLED | P2P_GROUP_OWNER)) ==
 375             P2P_MANAGE)
 376                 pos = hostapd_eid_p2p_manage(hapd, pos);
 377 #endif /* CONFIG_P2P_MANAGER */
 378
 379         if (hostapd_drv_send_mlme(hapd, resp, pos - (u8 *) resp) < 0)
 380                 perror("handle_probe_req: send");
 381
 382         os_free(resp);
 383
 384         wpa_printf(MSG_EXCESSIVE, "STA " MACSTR " sent probe request for %s "
 385                    "SSID", MAC2STR(mgmt->sa),
 386                    elems.ssid_len == 0 ? "broadcast" : "our");
 387 }
 388
 389
 390 void ieee802_11_set_beacon(struct hostapd_data *hapd)
 391 {
 392         struct ieee80211_mgmt *head;
 393         u8 *pos, *tail, *tailpos;
 394         u16 capab_info;
 395         size_t head_len, tail_len;
 396
 397 #ifdef CONFIG_P2P
 398         if ((hapd->conf->p2p & (P2P_ENABLED | P2P_GROUP_OWNER)) == P2P_ENABLED)
 399                 goto no_beacon;
 400 #endif /* CONFIG_P2P */
 401
 402 #define BEACON_HEAD_BUF_SIZE 256
 403 #define BEACON_TAIL_BUF_SIZE 512
 404         head = os_zalloc(BEACON_HEAD_BUF_SIZE);
 405         tail_len = BEACON_TAIL_BUF_SIZE;
 406 #ifdef CONFIG_WPS
 407         if (hapd->conf->wps_state && hapd->wps_beacon_ie)
 408                 tail_len += wpabuf_len(hapd->wps_beacon_ie);
 409 #endif /* CONFIG_WPS */
 410 #ifdef CONFIG_P2P
 411         if (hapd->p2p_beacon_ie)
 412                 tail_len += wpabuf_len(hapd->p2p_beacon_ie);
 413 #endif /* CONFIG_P2P */
 414         tailpos = tail = os_malloc(tail_len);
 415         if (head == NULL || tail == NULL) {
 416                 wpa_printf(MSG_ERROR, "Failed to set beacon data");
 417                 os_free(head);
 418                 os_free(tail);
 419                 return;
 420         }
 421
 422         head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 423                                            WLAN_FC_STYPE_BEACON);
 424         head->duration = host_to_le16(0);
 425         os_memset(head->da, 0xff, ETH_ALEN);
 426
 427         os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
 428         os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
 429         head->u.beacon.beacon_int =
 430                 host_to_le16(hapd->iconf->beacon_int);
 431
 432         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 433         capab_info = hostapd_own_capab_info(hapd, NULL, 0);
 434         head->u.beacon.capab_info = host_to_le16(capab_info);
 435         pos = &head->u.beacon.variable[0];
 436
 437         /* SSID */
 438         *pos++ = WLAN_EID_SSID;
 439         if (hapd->conf->ignore_broadcast_ssid == 2) {
 440                 /* clear the data, but keep the correct length of the SSID */
 441                 *pos++ = hapd->conf->ssid.ssid_len;
 442                 os_memset(pos, 0, hapd->conf->ssid.ssid_len);
 443                 pos += hapd->conf->ssid.ssid_len;
 444         } else if (hapd->conf->ignore_broadcast_ssid) {
 445                 *pos++ = 0; /* empty SSID */
 446         } else {
 447                 *pos++ = hapd->conf->ssid.ssid_len;
 448                 os_memcpy(pos, hapd->conf->ssid.ssid,
 449                           hapd->conf->ssid.ssid_len);
 450                 pos += hapd->conf->ssid.ssid_len;
 451         }
 452
 453         /* Supported rates */
 454         pos = hostapd_eid_supp_rates(hapd, pos);
 455
 456         /* DS Params */
 457         pos = hostapd_eid_ds_params(hapd, pos);
 458
 459         head_len = pos - (u8 *) head;
 460
 461         tailpos = hostapd_eid_country(hapd, tailpos,
 462                                       tail + BEACON_TAIL_BUF_SIZE - tailpos);
 463
 464         /* ERP Information element */
 465         tailpos = hostapd_eid_erp_info(hapd, tailpos);
 466
 467         /* Extended supported rates */
 468         tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
 469
 470         /* RSN, MDIE, WPA */
 471         tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
 472                                   tailpos, NULL);
 473
 474 #ifdef CONFIG_IEEE80211N
 475         tailpos = hostapd_eid_ht_capabilities(hapd, tailpos);
 476         tailpos = hostapd_eid_ht_operation(hapd, tailpos);
 477 #endif /* CONFIG_IEEE80211N */
 478
 479         /* Wi-Fi Alliance WMM */
 480         tailpos = hostapd_eid_wmm(hapd, tailpos);
 481
 482 #ifdef CONFIG_WPS
 483         if (hapd->conf->wps_state && hapd->wps_beacon_ie) {
 484                 os_memcpy(tailpos, wpabuf_head(hapd->wps_beacon_ie),
 485                           wpabuf_len(hapd->wps_beacon_ie));
 486                 tailpos += wpabuf_len(hapd->wps_beacon_ie);
 487         }
 488 #endif /* CONFIG_WPS */
 489
 490 #ifdef CONFIG_P2P
 491         if ((hapd->conf->p2p & P2P_ENABLED) && hapd->p2p_beacon_ie) {
 492                 os_memcpy(tailpos, wpabuf_head(hapd->p2p_beacon_ie),
 493                           wpabuf_len(hapd->p2p_beacon_ie));
 494                 tailpos += wpabuf_len(hapd->p2p_beacon_ie);
 495         }
 496 #endif /* CONFIG_P2P */
 497 #ifdef CONFIG_P2P_MANAGER
 498         if ((hapd->conf->p2p & (P2P_MANAGE | P2P_ENABLED | P2P_GROUP_OWNER)) ==
 499             P2P_MANAGE)
 500                 tailpos = hostapd_eid_p2p_manage(hapd, tailpos);
 501 #endif /* CONFIG_P2P_MANAGER */
 502
 503         tail_len = tailpos > tail ? tailpos - tail : 0;
 504
 505         if (hostapd_drv_set_beacon(hapd, (u8 *) head, head_len,
 506                                    tail, tail_len, hapd->conf->dtim_period,
 507                                    hapd->iconf->beacon_int))
 508                 wpa_printf(MSG_ERROR, "Failed to set beacon head/tail or DTIM "
 509                            "period");
 510
 511         os_free(tail);
 512         os_free(head);
 513
 514 #ifdef CONFIG_P2P
 515 no_beacon:
 516 #endif /* CONFIG_P2P */
 517         hapd->drv.set_bss_params(hapd, !!(ieee802_11_erp_info(hapd) &
 518                                           ERP_INFO_USE_PROTECTION));
 519 }
 520
 521
 522 void ieee802_11_set_beacons(struct hostapd_iface *iface)
 523 {
 524         size_t i;
 525         for (i = 0; i < iface->num_bss; i++)
 526                 ieee802_11_set_beacon(iface->bss[i]);
 527 }
 528
 529 #endif /* CONFIG_NATIVE_WINDOWS */