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 */ 457