hostapd/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, Jouni Malinen <j@w1.fi>
   6  * Copyright (c) 2007-2008, Intel Corporation
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * Alternatively, this software may be distributed under the terms of BSD
  13  * license.
  14  *
  15  * See README and COPYING for more details.
  16  */
  17
  18 #include "includes.h"
  19
  20 #ifndef CONFIG_NATIVE_WINDOWS
  21
  22 #include "hostapd.h"
  23 #include "ieee802_11.h"
  24 #include "wpa.h"
  25 #include "wme.h"
  26 #include "beacon.h"
  27 #include "hw_features.h"
  28 #include "driver.h"
  29 #include "sta_info.h"
  30 #include "wps_hostapd.h"
  31
  32
  33 static u8 ieee802_11_erp_info(struct hostapd_data *hapd)
  34 {
  35         u8 erp = 0;
  36
  37         if (hapd->iface->current_mode == NULL ||
  38             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  39                 return 0;
  40
  41         switch (hapd->iconf->cts_protection_type) {
  42         case CTS_PROTECTION_FORCE_ENABLED:
  43                 erp |= ERP_INFO_NON_ERP_PRESENT | ERP_INFO_USE_PROTECTION;
  44                 break;
  45         case CTS_PROTECTION_FORCE_DISABLED:
  46                 erp = 0;
  47                 break;
  48         case CTS_PROTECTION_AUTOMATIC:
  49                 if (hapd->iface->olbc)
  50                         erp |= ERP_INFO_USE_PROTECTION;
  51                 /* continue */
  52         case CTS_PROTECTION_AUTOMATIC_NO_OLBC:
  53                 if (hapd->iface->num_sta_non_erp > 0) {
  54                         erp |= ERP_INFO_NON_ERP_PRESENT |
  55                                 ERP_INFO_USE_PROTECTION;
  56                 }
  57                 break;
  58         }
  59         if (hapd->iface->num_sta_no_short_preamble > 0)
  60                 erp |= ERP_INFO_BARKER_PREAMBLE_MODE;
  61
  62         return erp;
  63 }
  64
  65
  66 static u8 * hostapd_eid_ds_params(struct hostapd_data *hapd, u8 *eid)
  67 {
  68         *eid++ = WLAN_EID_DS_PARAMS;
  69         *eid++ = 1;
  70         *eid++ = hapd->iconf->channel;
  71         return eid;
  72 }
  73
  74
  75 static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
  76 {
  77         if (hapd->iface->current_mode == NULL ||
  78             hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
  79                 return eid;
  80
  81         /* Set NonERP_present and use_protection bits if there
  82          * are any associated NonERP stations. */
  83         /* TODO: use_protection bit can be set to zero even if
  84          * there are NonERP stations present. This optimization
  85          * might be useful if NonERP stations are "quiet".
  86          * See 802.11g/D6 E-1 for recommended practice.
  87          * In addition, Non ERP present might be set, if AP detects Non ERP
  88          * operation on other APs. */
  89
  90         /* Add ERP Information element */
  91         *eid++ = WLAN_EID_ERP_INFO;
  92         *eid++ = 1;
  93         *eid++ = ieee802_11_erp_info(hapd);
  94
  95         return eid;
  96 }
  97
  98
  99 static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
 100                                 int max_len)
 101 {
 102         u8 *pos = eid;
 103
 104         if (!hapd->iconf->ieee80211d || max_len < 6)
 105                 return eid;
 106
 107         *pos++ = WLAN_EID_COUNTRY;
 108         pos++; /* length will be set later */
 109         os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
 110         pos += 3;
 111
 112         if ((pos - eid) & 1)
 113                 *pos++ = 0; /* pad for 16-bit alignment */
 114
 115         eid[1] = (pos - eid) - 2;
 116
 117         return pos;
 118 }
 119
 120
 121 static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
 122                             struct sta_info *sta)
 123 {
 124         const u8 *ie;
 125         size_t ielen;
 126
 127         ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
 128         if (ie == NULL || ielen > len)
 129                 return eid;
 130
 131         os_memcpy(eid, ie, ielen);
 132         return eid + ielen;
 133 }
 134
 135
 136 void handle_probe_req(struct hostapd_data *hapd, struct ieee80211_mgmt *mgmt,
 137                       size_t len)
 138 {
 139         struct ieee80211_mgmt *resp;
 140         struct ieee802_11_elems elems;
 141         char *ssid;
 142         u8 *pos, *epos, *ie;
 143         size_t ssid_len, ie_len;
 144         struct sta_info *sta = NULL;
 145
 146         ie = mgmt->u.probe_req.variable;
 147         ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
 148
 149         hostapd_wps_probe_req_rx(hapd, mgmt->sa, ie, ie_len);
 150
 151         if (!hapd->iconf->send_probe_response)
 152                 return;
 153
 154         if (ieee802_11_parse_elems(ie, ie_len, &elems, 0) == ParseFailed) {
 155                 wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
 156                            MAC2STR(mgmt->sa));
 157                 return;
 158         }
 159
 160         ssid = NULL;
 161         ssid_len = 0;
 162
 163         if ((!elems.ssid || !elems.supp_rates)) {
 164                 wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
 165                            "without SSID or supported rates element",
 166                            MAC2STR(mgmt->sa));
 167                 return;
 168         }
 169
 170         if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
 171                 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
 172                            "broadcast SSID ignored", MAC2STR(mgmt->sa));
 173                 return;
 174         }
 175
 176         sta = ap_get_sta(hapd, mgmt->sa);
 177
 178         if (elems.ssid_len == 0 ||
 179             (elems.ssid_len == hapd->conf->ssid.ssid_len &&
 180              os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
 181              0)) {
 182                 ssid = hapd->conf->ssid.ssid;
 183                 ssid_len = hapd->conf->ssid.ssid_len;
 184                 if (sta)
 185                         sta->ssid_probe = &hapd->conf->ssid;
 186         }
 187
 188         if (!ssid) {
 189                 if (!(mgmt->da[0] & 0x01)) {
 190                         char ssid_txt[33];
 191                         ieee802_11_print_ssid(ssid_txt, elems.ssid,
 192                                               elems.ssid_len);
 193                         wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
 194                                    " for foreign SSID '%s'",
 195                                    MAC2STR(mgmt->sa), ssid_txt);
 196                 }
 197                 return;
 198         }
 199
 200         /* TODO: verify that supp_rates contains at least one matching rate
 201          * with AP configuration */
 202 #define MAX_PROBERESP_LEN 768
 203         resp = os_zalloc(MAX_PROBERESP_LEN);
 204         if (resp == NULL)
 205                 return;
 206         epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
 207
 208         resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 209                                            WLAN_FC_STYPE_PROBE_RESP);
 210         os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
 211         os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
 212
 213         os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
 214         resp->u.probe_resp.beacon_int =
 215                 host_to_le16(hapd->iconf->beacon_int);
 216
 217         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 218         resp->u.probe_resp.capab_info =
 219                 host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
 220
 221         pos = resp->u.probe_resp.variable;
 222         *pos++ = WLAN_EID_SSID;
 223         *pos++ = ssid_len;
 224         os_memcpy(pos, ssid, ssid_len);
 225         pos += ssid_len;
 226
 227         /* Supported rates */
 228         pos = hostapd_eid_supp_rates(hapd, pos);
 229
 230         /* DS Params */
 231         pos = hostapd_eid_ds_params(hapd, pos);
 232
 233         pos = hostapd_eid_country(hapd, pos, epos - pos);
 234
 235         /* ERP Information element */
 236         pos = hostapd_eid_erp_info(hapd, pos);
 237
 238         /* Extended supported rates */
 239         pos = hostapd_eid_ext_supp_rates(hapd, pos);
 240
 241         pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
 242
 243         /* Wi-Fi Wireless Multimedia Extensions */
 244         pos = hostapd_eid_wme(hapd, pos);
 245
 246         pos = hostapd_eid_ht_capabilities_info(hapd, pos);
 247         pos = hostapd_eid_ht_operation(hapd, pos);
 248
 249 #ifdef CONFIG_WPS
 250         if (hapd->conf->wps_state && hapd->wps_probe_resp_ie) {
 251                 os_memcpy(pos, hapd->wps_probe_resp_ie,
 252                           hapd->wps_probe_resp_ie_len);
 253                 pos += hapd->wps_probe_resp_ie_len;
 254         }
 255 #endif /* CONFIG_WPS */
 256
 257         if (hostapd_send_mgmt_frame(hapd, resp, pos - (u8 *) resp, 0) < 0)
 258                 perror("handle_probe_req: send");
 259
 260         os_free(resp);
 261
 262         wpa_printf(MSG_MSGDUMP, "STA " MACSTR " sent probe request for %s "
 263                    "SSID", MAC2STR(mgmt->sa),
 264                    elems.ssid_len == 0 ? "broadcast" : "our");
 265 }
 266
 267
 268 void ieee802_11_set_beacon(struct hostapd_data *hapd)
 269 {
 270         struct ieee80211_mgmt *head;
 271         u8 *pos, *tail, *tailpos;
 272         int preamble;
 273         u16 capab_info;
 274         size_t head_len, tail_len;
 275         int cts_protection = ((ieee802_11_erp_info(hapd) &
 276                               ERP_INFO_USE_PROTECTION) ? 1 : 0);
 277
 278 #define BEACON_HEAD_BUF_SIZE 256
 279 #define BEACON_TAIL_BUF_SIZE 512
 280         head = os_zalloc(BEACON_HEAD_BUF_SIZE);
 281         tailpos = tail = os_malloc(BEACON_TAIL_BUF_SIZE);
 282         if (head == NULL || tail == NULL) {
 283                 wpa_printf(MSG_ERROR, "Failed to set beacon data");
 284                 os_free(head);
 285                 os_free(tail);
 286                 return;
 287         }
 288
 289         head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
 290                                            WLAN_FC_STYPE_BEACON);
 291         head->duration = host_to_le16(0);
 292         os_memset(head->da, 0xff, ETH_ALEN);
 293
 294         os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
 295         os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
 296         head->u.beacon.beacon_int =
 297                 host_to_le16(hapd->iconf->beacon_int);
 298
 299         /* hardware or low-level driver will setup seq_ctrl and timestamp */
 300         capab_info = hostapd_own_capab_info(hapd, NULL, 0);
 301         head->u.beacon.capab_info = host_to_le16(capab_info);
 302         pos = &head->u.beacon.variable[0];
 303
 304         /* SSID */
 305         *pos++ = WLAN_EID_SSID;
 306         if (hapd->conf->ignore_broadcast_ssid == 2) {
 307                 /* clear the data, but keep the correct length of the SSID */
 308                 *pos++ = hapd->conf->ssid.ssid_len;
 309                 os_memset(pos, 0, hapd->conf->ssid.ssid_len);
 310                 pos += hapd->conf->ssid.ssid_len;
 311         } else if (hapd->conf->ignore_broadcast_ssid) {
 312                 *pos++ = 0; /* empty SSID */
 313         } else {
 314                 *pos++ = hapd->conf->ssid.ssid_len;
 315                 os_memcpy(pos, hapd->conf->ssid.ssid,
 316                           hapd->conf->ssid.ssid_len);
 317                 pos += hapd->conf->ssid.ssid_len;
 318         }
 319
 320         /* Supported rates */
 321         pos = hostapd_eid_supp_rates(hapd, pos);
 322
 323         /* DS Params */
 324         pos = hostapd_eid_ds_params(hapd, pos);
 325
 326         head_len = pos - (u8 *) head;
 327
 328         tailpos = hostapd_eid_country(hapd, tailpos,
 329                                       tail + BEACON_TAIL_BUF_SIZE - tailpos);
 330
 331         /* ERP Information element */
 332         tailpos = hostapd_eid_erp_info(hapd, tailpos);
 333
 334         /* Extended supported rates */
 335         tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
 336
 337         tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
 338                                   tailpos, NULL);
 339
 340         /* Wi-Fi Wireless Multimedia Extensions */
 341         tailpos = hostapd_eid_wme(hapd, tailpos);
 342
 343 #ifdef CONFIG_IEEE80211N
 344         if (hapd->iconf->ieee80211n) {
 345                 u8 *start;
 346                 start = tailpos;
 347                 tailpos = hostapd_eid_ht_capabilities_info(hapd, tailpos);
 348                 if (hostapd_set_ht_capability(hapd->conf->iface, hapd,
 349                                               start + 2)) {
 350                         wpa_printf(MSG_ERROR, "Could not set HT capabilities "
 351                                    "for kernel driver");
 352                 }
 353
 354                 start = tailpos;
 355                 tailpos = hostapd_eid_ht_operation(hapd, tailpos);
 356                 if (hostapd_set_ht_operation(hapd->conf->iface, hapd,
 357                                              start + 2))
 358                         wpa_printf(MSG_ERROR, "Could not set HT operation for "
 359                                    "kernel driver");
 360         }
 361 #endif /* CONFIG_IEEE80211N */
 362
 363 #ifdef CONFIG_WPS
 364         if (hapd->conf->wps_state && hapd->wps_beacon_ie) {
 365                 os_memcpy(tailpos, hapd->wps_beacon_ie,
 366                           hapd->wps_beacon_ie_len);
 367                 tailpos += hapd->wps_beacon_ie_len;
 368         }
 369 #endif /* CONFIG_WPS */
 370
 371         tail_len = tailpos > tail ? tailpos - tail : 0;
 372
 373         if (hostapd_set_beacon(hapd->conf->iface, hapd, (u8 *) head, head_len,
 374                                tail, tail_len))
 375                 wpa_printf(MSG_ERROR, "Failed to set beacon head/tail");
 376
 377         os_free(tail);
 378         os_free(head);
 379
 380         if (hostapd_set_cts_protect(hapd, cts_protection))
 381                 wpa_printf(MSG_ERROR, "Failed to set CTS protect in kernel "
 382                            "driver");
 383
 384         if (hapd->iface->current_mode &&
 385             hapd->iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G &&
 386             hostapd_set_short_slot_time(hapd,
 387                                         hapd->iface->num_sta_no_short_slot_time
 388                                         > 0 ? 0 : 1))
 389                 wpa_printf(MSG_ERROR, "Failed to set Short Slot Time option "
 390                            "in kernel driver");
 391
 392         if (hapd->iface->num_sta_no_short_preamble == 0 &&
 393             hapd->iconf->preamble == SHORT_PREAMBLE)
 394                 preamble = SHORT_PREAMBLE;
 395         else
 396                 preamble = LONG_PREAMBLE;
 397         if (hostapd_set_preamble(hapd, preamble))
 398                 wpa_printf(MSG_ERROR, "Could not set preamble for kernel "
 399                            "driver");
 400 }
 401
 402
 403 void ieee802_11_set_beacons(struct hostapd_iface *iface)
 404 {
 405         size_t i;
 406         for (i = 0; i < iface->num_bss; i++)
 407                 ieee802_11_set_beacon(iface->bss[i]);
 408 }
 409
 410 #endif /* CONFIG_NATIVE_WINDOWS */