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6fc6879b JM |
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 |
6fc6879b JM |
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 | ||
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 && !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 | ||
122 | static 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 | ||
134 | static 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 | ||
146 | static 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 | ||
161 | static 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 | ||
176 | void 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 | ||
de9289c8 JM |
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 | ||
6fc6879b JM |
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 | ||
307 | void 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 | ||
de9289c8 JM |
387 | #ifdef CONFIG_IEEE80211N |
388 | if (hapd->conf->ieee80211n) { | |
edd360e1 JM |
389 | u8 *start; |
390 | start = tailpos; | |
de9289c8 | 391 | tailpos = hostapd_eid_ht_capabilities_info(hapd, tailpos); |
edd360e1 JM |
392 | if (hostapd_set_ht_capability(hapd->conf->iface, hapd, |
393 | start + 2)) { | |
de9289c8 JM |
394 | wpa_printf(MSG_ERROR, "Could not set HT capabilities " |
395 | "for kernel driver"); | |
396 | } | |
edd360e1 JM |
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)) | |
de9289c8 JM |
402 | wpa_printf(MSG_ERROR, "Could not set HT operation for " |
403 | "kernel driver"); | |
404 | } | |
405 | #endif /* CONFIG_IEEE80211N */ | |
406 | ||
6fc6879b JM |
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 | ||
439 | void 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 */ |