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