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[thirdparty/hostap.git] / hostapd / beacon.c
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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>
71b6ae14 6 * Copyright (c) 2007-2008, Intel Corporation
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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 "ieee802_11h.h"
31
32
33static 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
66static 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
75static 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
99static 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 && !hapd->iface->dfs_enable) ||
105 max_len < 6)
106 return eid;
107
108 *pos++ = WLAN_EID_COUNTRY;
109 pos++; /* length will be set later */
110 os_memcpy(pos, hapd->iconf->country, 3); /* e.g., 'US ' */
111 pos += 3;
112
113 if ((pos - eid) & 1)
114 *pos++ = 0; /* pad for 16-bit alignment */
115
116 eid[1] = (pos - eid) - 2;
117
118 return pos;
119}
120
121
122static u8 * hostapd_eid_power_constraint(struct hostapd_data *hapd, u8 *eid)
123
124{
125 if (!hapd->iface->dfs_enable)
126 return eid;
127 *eid++ = WLAN_EID_PWR_CONSTRAINT;
128 *eid++ = 1;
129 *eid++ = hapd->iface->pwr_const;
130 return eid;
131}
132
133
134static u8 * hostapd_eid_tpc_report(struct hostapd_data *hapd, u8 *eid)
135
136{
137 if (!hapd->iface->dfs_enable)
138 return eid;
139 *eid++ = WLAN_EID_TPC_REPORT;
140 *eid++ = 2;
141 *eid++ = hapd->iface->tx_power; /* TX POWER */
142 *eid++ = 0; /* Link Margin */
143 return eid;
144}
145
146static u8 * hostapd_eid_channel_switch(struct hostapd_data *hapd, u8 *eid)
147
148{
149 if (!hapd->iface->dfs_enable || !hapd->iface->channel_switch)
150 return eid;
151 *eid++ = WLAN_EID_CHANNEL_SWITCH;
152 *eid++ = 3;
153 *eid++ = CHAN_SWITCH_MODE_QUIET;
154 *eid++ = hapd->iface->channel_switch; /* New channel */
155 /* 0 - very soon; 1 - before next TBTT; num - after num beacons */
156 *eid++ = 0;
157 return eid;
158}
159
160
161static u8 * hostapd_eid_wpa(struct hostapd_data *hapd, u8 *eid, size_t len,
162 struct sta_info *sta)
163{
164 const u8 *ie;
165 size_t ielen;
166
167 ie = wpa_auth_get_wpa_ie(hapd->wpa_auth, &ielen);
168 if (ie == NULL || ielen > len)
169 return eid;
170
171 os_memcpy(eid, ie, ielen);
172 return eid + ielen;
173}
174
175
176void handle_probe_req(struct hostapd_data *hapd, struct ieee80211_mgmt *mgmt,
177 size_t len)
178{
179 struct ieee80211_mgmt *resp;
180 struct ieee802_11_elems elems;
181 char *ssid;
182 u8 *pos, *epos, *ie;
183 size_t ssid_len, ie_len;
184 struct sta_info *sta = NULL;
185
186 ie = mgmt->u.probe_req.variable;
187 ie_len = len - (IEEE80211_HDRLEN + sizeof(mgmt->u.probe_req));
188
189 if (!hapd->iconf->send_probe_response)
190 return;
191
192 if (ieee802_11_parse_elems(hapd, ie, ie_len, &elems, 0) == ParseFailed)
193 {
194 wpa_printf(MSG_DEBUG, "Could not parse ProbeReq from " MACSTR,
195 MAC2STR(mgmt->sa));
196 return;
197 }
198
199 ssid = NULL;
200 ssid_len = 0;
201
202 if ((!elems.ssid || !elems.supp_rates)) {
203 wpa_printf(MSG_DEBUG, "STA " MACSTR " sent probe request "
204 "without SSID or supported rates element",
205 MAC2STR(mgmt->sa));
206 return;
207 }
208
209 if (hapd->conf->ignore_broadcast_ssid && elems.ssid_len == 0) {
210 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR " for "
211 "broadcast SSID ignored", MAC2STR(mgmt->sa));
212 return;
213 }
214
215 sta = ap_get_sta(hapd, mgmt->sa);
216
217 if (elems.ssid_len == 0 ||
218 (elems.ssid_len == hapd->conf->ssid.ssid_len &&
219 os_memcmp(elems.ssid, hapd->conf->ssid.ssid, elems.ssid_len) ==
220 0)) {
221 ssid = hapd->conf->ssid.ssid;
222 ssid_len = hapd->conf->ssid.ssid_len;
223 if (sta)
224 sta->ssid_probe = &hapd->conf->ssid;
225 }
226
227 if (!ssid) {
228 if (!(mgmt->da[0] & 0x01)) {
229 char ssid_txt[33];
230 ieee802_11_print_ssid(ssid_txt, elems.ssid,
231 elems.ssid_len);
232 wpa_printf(MSG_MSGDUMP, "Probe Request from " MACSTR
233 " for foreign SSID '%s'",
234 MAC2STR(mgmt->sa), ssid_txt);
235 }
236 return;
237 }
238
239 /* TODO: verify that supp_rates contains at least one matching rate
240 * with AP configuration */
241#define MAX_PROBERESP_LEN 768
242 resp = os_zalloc(MAX_PROBERESP_LEN);
243 if (resp == NULL)
244 return;
245 epos = ((u8 *) resp) + MAX_PROBERESP_LEN;
246
247 resp->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
248 WLAN_FC_STYPE_PROBE_RESP);
249 os_memcpy(resp->da, mgmt->sa, ETH_ALEN);
250 os_memcpy(resp->sa, hapd->own_addr, ETH_ALEN);
251
252 os_memcpy(resp->bssid, hapd->own_addr, ETH_ALEN);
253 resp->u.probe_resp.beacon_int =
254 host_to_le16(hapd->iconf->beacon_int);
255
256 /* hardware or low-level driver will setup seq_ctrl and timestamp */
257 resp->u.probe_resp.capab_info =
258 host_to_le16(hostapd_own_capab_info(hapd, sta, 1));
259
260 pos = resp->u.probe_resp.variable;
261 *pos++ = WLAN_EID_SSID;
262 *pos++ = ssid_len;
263 os_memcpy(pos, ssid, ssid_len);
264 pos += ssid_len;
265
266 /* Supported rates */
267 pos = hostapd_eid_supp_rates(hapd, pos);
268
269 /* DS Params */
270 pos = hostapd_eid_ds_params(hapd, pos);
271
272 pos = hostapd_eid_country(hapd, pos, epos - pos);
273
274 pos = hostapd_eid_power_constraint(hapd, pos);
275 pos = hostapd_eid_tpc_report(hapd, pos);
276
277 /* ERP Information element */
278 pos = hostapd_eid_erp_info(hapd, pos);
279
280 /* Extended supported rates */
281 pos = hostapd_eid_ext_supp_rates(hapd, pos);
282
283 pos = hostapd_eid_wpa(hapd, pos, epos - pos, sta);
284
285 /* Wi-Fi Wireless Multimedia Extensions */
286 if (hapd->conf->wme_enabled)
287 pos = hostapd_eid_wme(hapd, pos);
288
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289#ifdef CONFIG_IEEE80211N
290 if (hapd->conf->ieee80211n) {
291 pos = hostapd_eid_ht_capabilities_info(hapd, pos);
292 pos = hostapd_eid_ht_operation(hapd, pos);
293 }
294#endif /* CONFIG_IEEE80211N */
295
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296 if (hostapd_send_mgmt_frame(hapd, resp, pos - (u8 *) resp, 0) < 0)
297 perror("handle_probe_req: send");
298
299 os_free(resp);
300
301 wpa_printf(MSG_MSGDUMP, "STA " MACSTR " sent probe request for %s "
302 "SSID", MAC2STR(mgmt->sa),
303 elems.ssid_len == 0 ? "broadcast" : "our");
304}
305
306
307void ieee802_11_set_beacon(struct hostapd_data *hapd)
308{
309 struct ieee80211_mgmt *head;
310 u8 *pos, *tail, *tailpos;
311 int preamble;
312 u16 capab_info;
313 size_t head_len, tail_len;
314 int cts_protection = ((ieee802_11_erp_info(hapd) &
315 ERP_INFO_USE_PROTECTION) ? 1 : 0);
316
317#define BEACON_HEAD_BUF_SIZE 256
318#define BEACON_TAIL_BUF_SIZE 512
319 head = os_zalloc(BEACON_HEAD_BUF_SIZE);
320 tailpos = tail = os_malloc(BEACON_TAIL_BUF_SIZE);
321 if (head == NULL || tail == NULL) {
322 wpa_printf(MSG_ERROR, "Failed to set beacon data");
323 os_free(head);
324 os_free(tail);
325 return;
326 }
327
328 head->frame_control = IEEE80211_FC(WLAN_FC_TYPE_MGMT,
329 WLAN_FC_STYPE_BEACON);
330 head->duration = host_to_le16(0);
331 os_memset(head->da, 0xff, ETH_ALEN);
332
333 os_memcpy(head->sa, hapd->own_addr, ETH_ALEN);
334 os_memcpy(head->bssid, hapd->own_addr, ETH_ALEN);
335 head->u.beacon.beacon_int =
336 host_to_le16(hapd->iconf->beacon_int);
337
338 /* hardware or low-level driver will setup seq_ctrl and timestamp */
339 capab_info = hostapd_own_capab_info(hapd, NULL, 0);
340 head->u.beacon.capab_info = host_to_le16(capab_info);
341 pos = &head->u.beacon.variable[0];
342
343 /* SSID */
344 *pos++ = WLAN_EID_SSID;
345 if (hapd->conf->ignore_broadcast_ssid == 2) {
346 /* clear the data, but keep the correct length of the SSID */
347 *pos++ = hapd->conf->ssid.ssid_len;
348 os_memset(pos, 0, hapd->conf->ssid.ssid_len);
349 pos += hapd->conf->ssid.ssid_len;
350 } else if (hapd->conf->ignore_broadcast_ssid) {
351 *pos++ = 0; /* empty SSID */
352 } else {
353 *pos++ = hapd->conf->ssid.ssid_len;
354 os_memcpy(pos, hapd->conf->ssid.ssid,
355 hapd->conf->ssid.ssid_len);
356 pos += hapd->conf->ssid.ssid_len;
357 }
358
359 /* Supported rates */
360 pos = hostapd_eid_supp_rates(hapd, pos);
361
362 /* DS Params */
363 pos = hostapd_eid_ds_params(hapd, pos);
364
365 head_len = pos - (u8 *) head;
366
367 tailpos = hostapd_eid_country(hapd, tailpos,
368 tail + BEACON_TAIL_BUF_SIZE - tailpos);
369
370 tailpos = hostapd_eid_power_constraint(hapd, tailpos);
371 tailpos = hostapd_eid_channel_switch(hapd, tailpos);
372 tailpos = hostapd_eid_tpc_report(hapd, tailpos);
373
374 /* ERP Information element */
375 tailpos = hostapd_eid_erp_info(hapd, tailpos);
376
377 /* Extended supported rates */
378 tailpos = hostapd_eid_ext_supp_rates(hapd, tailpos);
379
380 tailpos = hostapd_eid_wpa(hapd, tailpos, tail + BEACON_TAIL_BUF_SIZE -
381 tailpos, NULL);
382
383 /* Wi-Fi Wireless Multimedia Extensions */
384 if (hapd->conf->wme_enabled)
385 tailpos = hostapd_eid_wme(hapd, tailpos);
386
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387#ifdef CONFIG_IEEE80211N
388 if (hapd->conf->ieee80211n) {
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389 u8 *start;
390 start = tailpos;
de9289c8 391 tailpos = hostapd_eid_ht_capabilities_info(hapd, tailpos);
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392 if (hostapd_set_ht_capability(hapd->conf->iface, hapd,
393 start + 2)) {
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394 wpa_printf(MSG_ERROR, "Could not set HT capabilities "
395 "for kernel driver");
396 }
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397
398 start = tailpos;
399 tailpos = hostapd_eid_ht_operation(hapd, tailpos);
400 if (hostapd_set_ht_operation(hapd->conf->iface, hapd,
401 start + 2))
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402 wpa_printf(MSG_ERROR, "Could not set HT operation for "
403 "kernel driver");
404 }
405#endif /* CONFIG_IEEE80211N */
406
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407 tail_len = tailpos > tail ? tailpos - tail : 0;
408
409 if (hostapd_set_beacon(hapd->conf->iface, hapd, (u8 *) head, head_len,
410 tail, tail_len))
411 wpa_printf(MSG_ERROR, "Failed to set beacon head/tail");
412
413 os_free(tail);
414 os_free(head);
415
416 if (hostapd_set_cts_protect(hapd, cts_protection))
417 wpa_printf(MSG_ERROR, "Failed to set CTS protect in kernel "
418 "driver");
419
420 if (hapd->iface->current_mode &&
421 hapd->iface->current_mode->mode == HOSTAPD_MODE_IEEE80211G &&
422 hostapd_set_short_slot_time(hapd,
423 hapd->iface->num_sta_no_short_slot_time
424 > 0 ? 0 : 1))
425 wpa_printf(MSG_ERROR, "Failed to set Short Slot Time option "
426 "in kernel driver");
427
428 if (hapd->iface->num_sta_no_short_preamble == 0 &&
429 hapd->iconf->preamble == SHORT_PREAMBLE)
430 preamble = SHORT_PREAMBLE;
431 else
432 preamble = LONG_PREAMBLE;
433 if (hostapd_set_preamble(hapd, preamble))
434 wpa_printf(MSG_ERROR, "Could not set preamble for kernel "
435 "driver");
436}
437
438
439void ieee802_11_set_beacons(struct hostapd_iface *iface)
440{
441 size_t i;
442 for (i = 0; i < iface->num_bss; i++)
443 ieee802_11_set_beacon(iface->bss[i]);
444}
445
446#endif /* CONFIG_NATIVE_WINDOWS */