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>
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.
11 * Alternatively, this software may be distributed under the terms of BSD
14 * See README and COPYING for more details.
17 #include "utils/includes.h"
19 #ifndef CONFIG_NATIVE_WINDOWS
21 #include "utils/common.h"
22 #include "common/ieee802_11_defs.h"
23 #include "common/ieee802_11_common.h"
24 #include "drivers/driver.h"
26 #include "ieee802_11.h"
29 #include "ap_config.h"
34 static u8 ieee802_11_erp_info(struct hostapd_data *hapd)
38 if (hapd->iface->current_mode == NULL ||
39 hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
42 switch (hapd->iconf->cts_protection_type) {
43 case CTS_PROTECTION_FORCE_ENABLED:
44 erp |= ERP_INFO_NON_ERP_PRESENT | ERP_INFO_USE_PROTECTION;
46 case CTS_PROTECTION_FORCE_DISABLED:
49 case CTS_PROTECTION_AUTOMATIC:
50 if (hapd->iface->olbc)
51 erp |= ERP_INFO_USE_PROTECTION;
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;
60 if (hapd->iface->num_sta_no_short_preamble > 0)
61 erp |= ERP_INFO_BARKER_PREAMBLE_MODE;
67 static u8 * hostapd_eid_ds_params(struct hostapd_data *hapd, u8 *eid)
69 *eid++ = WLAN_EID_DS_PARAMS;
71 *eid++ = hapd->iconf->channel;
76 static u8 * hostapd_eid_erp_info(struct hostapd_data *hapd, u8 *eid)
78 if (hapd->iface->current_mode == NULL ||
79 hapd->iface->current_mode->mode != HOSTAPD_MODE_IEEE80211G)
82 /* Set NonERP_present and use_protection bits if there
83 * are any associated NonERP stations. */
84 /* TODO: use_protection bit can be set to zero even if
85 * there are NonERP stations present. This optimization
86 * might be useful if NonERP stations are "quiet".
87 * See 802.11g/D6 E-1 for recommended practice.
88 * In addition, Non ERP present might be set, if AP detects Non ERP
89 * operation on other APs. */
91 /* Add ERP Information element */
92 *eid++ = WLAN_EID_ERP_INFO;
94 *eid++ = ieee802_11_erp_info(hapd);
100 static u8 * hostapd_eid_country_add(u8 *pos, u8 *end, int chan_spacing,
101 struct hostapd_channel_data *start,
102 struct hostapd_channel_data *prev)
107 /* first channel number */
108 *pos++ = start->chan;
109 /* number of channels */
110 *pos++ = (prev->chan - start->chan) / chan_spacing + 1;
111 /* maximum transmit power level */
112 *pos++ = start->max_tx_power;
118 static u8 * hostapd_eid_country(struct hostapd_data *hapd, u8 *eid,
122 u8 *end = eid + max_len;
124 struct hostapd_hw_modes *mode;
125 struct hostapd_channel_data *start, *prev;
126 int chan_spacing = 1;
128 if (!hapd->iconf->ieee80211d || max_len < 6 ||
129 hapd->iface->current_mode == NULL)
132 *pos++ = WLAN_EID_COUNTRY;
133 pos++; /* length will be set later */
134 os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
137 mode = hapd->iface->current_mode;
138 if (mode->mode == HOSTAPD_MODE_IEEE80211A)
142 for (i = 0; i < mode->num_channels; i++) {
143 struct hostapd_channel_data *chan = &mode->channels[i];
144 if (chan->flag & HOSTAPD_CHAN_DISABLED)
147 prev->chan + chan_spacing == chan->chan &&
148 start->max_tx_power == chan->max_tx_power) {
150 continue; /* can use same entry */
154 pos = hostapd_eid_country_add(pos, end, chan_spacing,
159 /* Start new group */
164 pos = hostapd_eid_country_add(pos, end, chan_spacing,
168 if ((pos - eid) & 1) {
171 *pos++ = 0; /* pad for 16-bit alignment */
174 eid[1] = (pos - eid) - 2;
180 static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
181 struct sta_info *sta)
186 ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
187 if (ie == NULL || ielen > len)
190 os_memcpy(eid, ie, ielen);
195 void handle_probe_req(struct hostapd_data *hapd,
196 const struct ieee80211_mgmt *mgmt, size_t len)
198 struct ieee80211_mgmt *resp;
199 struct ieee802_11_elems elems;
203 size_t ssid_len, ie_len;
204 struct sta_info *sta = NULL;
208 ie = mgmt->u.probe_req.variable;
209 ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
211 for (i = 0; hapd->probereq_cb && i < hapd->num_probereq_cb; i++)
212 if (hapd->probereq_cb[i].cb(hapd->probereq_cb[i].ctx,
213 mgmt->sa, ie, ie_len) > 0)
216 if (!hapd->iconf->send_probe_response)
219 if (ieee802_11_parse_elems(ie, ie_len, &elems, 0) == ParseFailed) {
220 wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
228 if ((!elems.ssid || !elems.supp_rates)) {
229 wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
230 "without SSID or supported rates element",
235 if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
236 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
237 "broadcast SSID ignored", MAC2STR(mgmt->sa));
241 sta = ap_get_sta(hapd, mgmt->sa);
243 if (elems.ssid_len == 0 ||
244 (elems.ssid_len == hapd->conf->ssid.ssid_len &&
245 os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
247 ssid = hapd->conf->ssid.ssid;
248 ssid_len = hapd->conf->ssid.ssid_len;
250 sta->ssid_probe = &hapd->conf->ssid;
254 if (!(mgmt->da[0] & 0x01)) {
256 ieee802_11_print_ssid(ssid_txt, elems.ssid,
258 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
259 " for foreign SSID '%s'",
260 MAC2STR(mgmt->sa), ssid_txt);
265 /* TODO: verify that supp_rates contains at least one matching rate
266 * with AP configuration */
267 #define MAX_PROBERESP_LEN 768
268 buflen = MAX_PROBERESP_LEN;
270 if (hapd->wps_probe_resp_ie)
271 buflen += wpabuf_len(hapd->wps_probe_resp_ie);
272 #endif /* CONFIG_WPS */
273 resp = os_zalloc(buflen);
276 epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
278 resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
279 WLAN_FC_STYPE_PROBE_RESP);
280 os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
281 os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
283 os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
284 resp->u.probe_resp.beacon_int =
285 host_to_le16(hapd->iconf->beacon_int);
287 /* hardware or low-level driver will setup seq_ctrl and timestamp */
288 resp->u.probe_resp.capab_info =
289 host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
291 pos = resp->u.probe_resp.variable;
292 *pos++ = WLAN_EID_SSID;
294 os_memcpy(pos, ssid, ssid_len);
297 /* Supported rates */
298 pos = hostapd_eid_supp_rates(hapd, pos);
301 pos = hostapd_eid_ds_params(hapd, pos);
303 pos = hostapd_eid_country(hapd, pos, epos - pos);
305 /* ERP Information element */
306 pos = hostapd_eid_erp_info(hapd, pos);
308 /* Extended supported rates */
309 pos = hostapd_eid_ext_supp_rates(hapd, pos);
312 pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
314 #ifdef CONFIG_IEEE80211N
315 pos = hostapd_eid_ht_capabilities(hapd, pos);
316 pos = hostapd_eid_ht_operation(hapd, pos);
317 #endif /* CONFIG_IEEE80211N */
319 /* Wi-Fi Alliance WMM */
320 pos = hostapd_eid_wmm(hapd, pos);
323 if (hapd->conf->wps_state && hapd->wps_probe_resp_ie) {
324 os_memcpy(pos, wpabuf_head(hapd->wps_probe_resp_ie),
325 wpabuf_len(hapd->wps_probe_resp_ie));
326 pos += wpabuf_len(hapd->wps_probe_resp_ie);
328 #endif /* CONFIG_WPS */
330 if (hapd->drv.send_mgmt_frame(hapd, resp, pos - (u8 *) resp) < 0)
331 perror("handle_probe_req: send");
335 wpa_printf(MSG_MSGDUMP, "STA " MACSTR " sent probe request for %s "
336 "SSID", MAC2STR(mgmt->sa),
337 elems.ssid_len == 0 ? "broadcast" : "our");
341 void ieee802_11_set_beacon(struct hostapd_data *hapd)
343 struct ieee80211_mgmt *head;
344 u8 *pos, *tail, *tailpos;
346 size_t head_len, tail_len;
348 #define BEACON_HEAD_BUF_SIZE 256
349 #define BEACON_TAIL_BUF_SIZE 512
350 head = os_zalloc(BEACON_HEAD_BUF_SIZE);
351 tail_len = BEACON_TAIL_BUF_SIZE;
353 if (hapd->conf->wps_state && hapd->wps_beacon_ie)
354 tail_len += wpabuf_len(hapd->wps_beacon_ie);
355 #endif /* CONFIG_WPS */
356 tailpos = tail = os_malloc(tail_len);
357 if (head == NULL || tail == NULL) {
358 wpa_printf(MSG_ERROR, "Failed to set beacon data");
364 head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
365 WLAN_FC_STYPE_BEACON);
366 head->duration = host_to_le16(0);
367 os_memset(head->da, 0xff, ETH_ALEN);
369 os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
370 os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
371 head->u.beacon.beacon_int =
372 host_to_le16(hapd->iconf->beacon_int);
374 /* hardware or low-level driver will setup seq_ctrl and timestamp */
375 capab_info = hostapd_own_capab_info(hapd, NULL, 0);
376 head->u.beacon.capab_info = host_to_le16(capab_info);
377 pos = &head->u.beacon.variable[0];
380 *pos++ = WLAN_EID_SSID;
381 if (hapd->conf->ignore_broadcast_ssid == 2) {
382 /* clear the data, but keep the correct length of the SSID */
383 *pos++ = hapd->conf->ssid.ssid_len;
384 os_memset(pos, 0, hapd->conf->ssid.ssid_len);
385 pos += hapd->conf->ssid.ssid_len;
386 } else if (hapd->conf->ignore_broadcast_ssid) {
387 *pos++ = 0; /* empty SSID */
389 *pos++ = hapd->conf->ssid.ssid_len;
390 os_memcpy(pos, hapd->conf->ssid.ssid,
391 hapd->conf->ssid.ssid_len);
392 pos += hapd->conf->ssid.ssid_len;
395 /* Supported rates */
396 pos = hostapd_eid_supp_rates(hapd, pos);
399 pos = hostapd_eid_ds_params(hapd, pos);
401 head_len = pos - (u8 *) head;
403 tailpos = hostapd_eid_country(hapd, tailpos,
404 tail + BEACON_TAIL_BUF_SIZE - tailpos);
406 /* ERP Information element */
407 tailpos = hostapd_eid_erp_info(hapd, tailpos);
409 /* Extended supported rates */
410 tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
413 tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
416 #ifdef CONFIG_IEEE80211N
417 tailpos = hostapd_eid_ht_capabilities(hapd, tailpos);
418 tailpos = hostapd_eid_ht_operation(hapd, tailpos);
419 #endif /* CONFIG_IEEE80211N */
421 /* Wi-Fi Alliance WMM */
422 tailpos = hostapd_eid_wmm(hapd, tailpos);
425 if (hapd->conf->wps_state && hapd->wps_beacon_ie) {
426 os_memcpy(tailpos, wpabuf_head(hapd->wps_beacon_ie),
427 wpabuf_len(hapd->wps_beacon_ie));
428 tailpos += wpabuf_len(hapd->wps_beacon_ie);
430 #endif /* CONFIG_WPS */
432 tail_len = tailpos > tail ? tailpos - tail : 0;
434 if (hapd->drv.set_beacon(hapd, (u8 *) head, head_len,
435 tail, tail_len, hapd->conf->dtim_period,
436 hapd->iconf->beacon_int))
437 wpa_printf(MSG_ERROR, "Failed to set beacon head/tail or DTIM "
443 hapd->drv.set_bss_params(hapd, !!(ieee802_11_erp_info(hapd) &
444 ERP_INFO_USE_PROTECTION));
448 void ieee802_11_set_beacons(struct hostapd_iface *iface)
451 for (i = 0; i < iface->num_bss; i++)
452 ieee802_11_set_beacon(iface->bss[i]);
455 #endif /* CONFIG_NATIVE_WINDOWS */