xref: /openbmc/linux/net/mac80211/spectmgmt.c (revision b34e08d5)
1 /*
2  * spectrum management
3  *
4  * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi>
5  * Copyright 2002-2005, Instant802 Networks, Inc.
6  * Copyright 2005-2006, Devicescape Software, Inc.
7  * Copyright 2006-2007  Jiri Benc <jbenc@suse.cz>
8  * Copyright 2007, Michael Wu <flamingice@sourmilk.net>
9  * Copyright 2007-2008, Intel Corporation
10  * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
11  *
12  * This program is free software; you can redistribute it and/or modify
13  * it under the terms of the GNU General Public License version 2 as
14  * published by the Free Software Foundation.
15  */
16 
17 #include <linux/ieee80211.h>
18 #include <net/cfg80211.h>
19 #include <net/mac80211.h>
20 #include "ieee80211_i.h"
21 #include "sta_info.h"
22 #include "wme.h"
23 
24 int ieee80211_parse_ch_switch_ie(struct ieee80211_sub_if_data *sdata,
25 				 struct ieee802_11_elems *elems, bool beacon,
26 				 enum ieee80211_band current_band,
27 				 u32 sta_flags, u8 *bssid,
28 				 struct ieee80211_csa_ie *csa_ie)
29 {
30 	enum ieee80211_band new_band;
31 	int new_freq;
32 	u8 new_chan_no;
33 	struct ieee80211_channel *new_chan;
34 	struct cfg80211_chan_def new_vht_chandef = {};
35 	const struct ieee80211_sec_chan_offs_ie *sec_chan_offs;
36 	const struct ieee80211_wide_bw_chansw_ie *wide_bw_chansw_ie;
37 	const struct ieee80211_ht_operation *ht_oper;
38 	int secondary_channel_offset = -1;
39 
40 	sec_chan_offs = elems->sec_chan_offs;
41 	wide_bw_chansw_ie = elems->wide_bw_chansw_ie;
42 	ht_oper = elems->ht_operation;
43 
44 	if (sta_flags & (IEEE80211_STA_DISABLE_HT |
45 			 IEEE80211_STA_DISABLE_40MHZ)) {
46 		sec_chan_offs = NULL;
47 		wide_bw_chansw_ie = NULL;
48 		/* only used for bandwidth here */
49 		ht_oper = NULL;
50 	}
51 
52 	if (sta_flags & IEEE80211_STA_DISABLE_VHT)
53 		wide_bw_chansw_ie = NULL;
54 
55 	if (elems->ext_chansw_ie) {
56 		if (!ieee80211_operating_class_to_band(
57 				elems->ext_chansw_ie->new_operating_class,
58 				&new_band)) {
59 			sdata_info(sdata,
60 				   "cannot understand ECSA IE operating class %d, disconnecting\n",
61 				   elems->ext_chansw_ie->new_operating_class);
62 			return -EINVAL;
63 		}
64 		new_chan_no = elems->ext_chansw_ie->new_ch_num;
65 		csa_ie->count = elems->ext_chansw_ie->count;
66 		csa_ie->mode = elems->ext_chansw_ie->mode;
67 	} else if (elems->ch_switch_ie) {
68 		new_band = current_band;
69 		new_chan_no = elems->ch_switch_ie->new_ch_num;
70 		csa_ie->count = elems->ch_switch_ie->count;
71 		csa_ie->mode = elems->ch_switch_ie->mode;
72 	} else {
73 		/* nothing here we understand */
74 		return 1;
75 	}
76 
77 	/* Mesh Channel Switch Parameters Element */
78 	if (elems->mesh_chansw_params_ie) {
79 		csa_ie->ttl = elems->mesh_chansw_params_ie->mesh_ttl;
80 		csa_ie->mode = elems->mesh_chansw_params_ie->mesh_flags;
81 		csa_ie->pre_value = le16_to_cpu(
82 				elems->mesh_chansw_params_ie->mesh_pre_value);
83 	}
84 
85 	new_freq = ieee80211_channel_to_frequency(new_chan_no, new_band);
86 	new_chan = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
87 	if (!new_chan || new_chan->flags & IEEE80211_CHAN_DISABLED) {
88 		sdata_info(sdata,
89 			   "BSS %pM switches to unsupported channel (%d MHz), disconnecting\n",
90 			   bssid, new_freq);
91 		return -EINVAL;
92 	}
93 
94 	if (!beacon && sec_chan_offs) {
95 		secondary_channel_offset = sec_chan_offs->sec_chan_offs;
96 	} else if (beacon && ht_oper) {
97 		secondary_channel_offset =
98 			ht_oper->ht_param & IEEE80211_HT_PARAM_CHA_SEC_OFFSET;
99 	} else if (!(sta_flags & IEEE80211_STA_DISABLE_HT)) {
100 		/* If it's not a beacon, HT is enabled and the IE not present,
101 		 * it's 20 MHz, 802.11-2012 8.5.2.6:
102 		 *	This element [the Secondary Channel Offset Element] is
103 		 *	present when switching to a 40 MHz channel. It may be
104 		 *	present when switching to a 20 MHz channel (in which
105 		 *	case the secondary channel offset is set to SCN).
106 		 */
107 		secondary_channel_offset = IEEE80211_HT_PARAM_CHA_SEC_NONE;
108 	}
109 
110 	switch (secondary_channel_offset) {
111 	default:
112 		/* secondary_channel_offset was present but is invalid */
113 	case IEEE80211_HT_PARAM_CHA_SEC_NONE:
114 		cfg80211_chandef_create(&csa_ie->chandef, new_chan,
115 					NL80211_CHAN_HT20);
116 		break;
117 	case IEEE80211_HT_PARAM_CHA_SEC_ABOVE:
118 		cfg80211_chandef_create(&csa_ie->chandef, new_chan,
119 					NL80211_CHAN_HT40PLUS);
120 		break;
121 	case IEEE80211_HT_PARAM_CHA_SEC_BELOW:
122 		cfg80211_chandef_create(&csa_ie->chandef, new_chan,
123 					NL80211_CHAN_HT40MINUS);
124 		break;
125 	case -1:
126 		cfg80211_chandef_create(&csa_ie->chandef, new_chan,
127 					NL80211_CHAN_NO_HT);
128 		/* keep width for 5/10 MHz channels */
129 		switch (sdata->vif.bss_conf.chandef.width) {
130 		case NL80211_CHAN_WIDTH_5:
131 		case NL80211_CHAN_WIDTH_10:
132 			csa_ie->chandef.width =
133 				sdata->vif.bss_conf.chandef.width;
134 			break;
135 		default:
136 			break;
137 		}
138 		break;
139 	}
140 
141 	if (wide_bw_chansw_ie) {
142 		new_vht_chandef.chan = new_chan;
143 		new_vht_chandef.center_freq1 =
144 			ieee80211_channel_to_frequency(
145 				wide_bw_chansw_ie->new_center_freq_seg0,
146 				new_band);
147 
148 		switch (wide_bw_chansw_ie->new_channel_width) {
149 		default:
150 			/* hmmm, ignore VHT and use HT if present */
151 		case IEEE80211_VHT_CHANWIDTH_USE_HT:
152 			new_vht_chandef.chan = NULL;
153 			break;
154 		case IEEE80211_VHT_CHANWIDTH_80MHZ:
155 			new_vht_chandef.width = NL80211_CHAN_WIDTH_80;
156 			break;
157 		case IEEE80211_VHT_CHANWIDTH_160MHZ:
158 			new_vht_chandef.width = NL80211_CHAN_WIDTH_160;
159 			break;
160 		case IEEE80211_VHT_CHANWIDTH_80P80MHZ:
161 			/* field is otherwise reserved */
162 			new_vht_chandef.center_freq2 =
163 				ieee80211_channel_to_frequency(
164 					wide_bw_chansw_ie->new_center_freq_seg1,
165 					new_band);
166 			new_vht_chandef.width = NL80211_CHAN_WIDTH_80P80;
167 			break;
168 		}
169 		if (sta_flags & IEEE80211_STA_DISABLE_80P80MHZ &&
170 		    new_vht_chandef.width == NL80211_CHAN_WIDTH_80P80)
171 			ieee80211_chandef_downgrade(&new_vht_chandef);
172 		if (sta_flags & IEEE80211_STA_DISABLE_160MHZ &&
173 		    new_vht_chandef.width == NL80211_CHAN_WIDTH_160)
174 			ieee80211_chandef_downgrade(&new_vht_chandef);
175 		if (sta_flags & IEEE80211_STA_DISABLE_40MHZ &&
176 		    new_vht_chandef.width > NL80211_CHAN_WIDTH_20)
177 			ieee80211_chandef_downgrade(&new_vht_chandef);
178 	}
179 
180 	/* if VHT data is there validate & use it */
181 	if (new_vht_chandef.chan) {
182 		if (!cfg80211_chandef_compatible(&new_vht_chandef,
183 						 &csa_ie->chandef)) {
184 			sdata_info(sdata,
185 				   "BSS %pM: CSA has inconsistent channel data, disconnecting\n",
186 				   bssid);
187 			return -EINVAL;
188 		}
189 		csa_ie->chandef = new_vht_chandef;
190 	}
191 
192 	return 0;
193 }
194 
195 static void ieee80211_send_refuse_measurement_request(struct ieee80211_sub_if_data *sdata,
196 					struct ieee80211_msrment_ie *request_ie,
197 					const u8 *da, const u8 *bssid,
198 					u8 dialog_token)
199 {
200 	struct ieee80211_local *local = sdata->local;
201 	struct sk_buff *skb;
202 	struct ieee80211_mgmt *msr_report;
203 
204 	skb = dev_alloc_skb(sizeof(*msr_report) + local->hw.extra_tx_headroom +
205 				sizeof(struct ieee80211_msrment_ie));
206 	if (!skb)
207 		return;
208 
209 	skb_reserve(skb, local->hw.extra_tx_headroom);
210 	msr_report = (struct ieee80211_mgmt *)skb_put(skb, 24);
211 	memset(msr_report, 0, 24);
212 	memcpy(msr_report->da, da, ETH_ALEN);
213 	memcpy(msr_report->sa, sdata->vif.addr, ETH_ALEN);
214 	memcpy(msr_report->bssid, bssid, ETH_ALEN);
215 	msr_report->frame_control = cpu_to_le16(IEEE80211_FTYPE_MGMT |
216 						IEEE80211_STYPE_ACTION);
217 
218 	skb_put(skb, 1 + sizeof(msr_report->u.action.u.measurement));
219 	msr_report->u.action.category = WLAN_CATEGORY_SPECTRUM_MGMT;
220 	msr_report->u.action.u.measurement.action_code =
221 				WLAN_ACTION_SPCT_MSR_RPRT;
222 	msr_report->u.action.u.measurement.dialog_token = dialog_token;
223 
224 	msr_report->u.action.u.measurement.element_id = WLAN_EID_MEASURE_REPORT;
225 	msr_report->u.action.u.measurement.length =
226 			sizeof(struct ieee80211_msrment_ie);
227 
228 	memset(&msr_report->u.action.u.measurement.msr_elem, 0,
229 		sizeof(struct ieee80211_msrment_ie));
230 	msr_report->u.action.u.measurement.msr_elem.token = request_ie->token;
231 	msr_report->u.action.u.measurement.msr_elem.mode |=
232 			IEEE80211_SPCT_MSR_RPRT_MODE_REFUSED;
233 	msr_report->u.action.u.measurement.msr_elem.type = request_ie->type;
234 
235 	ieee80211_tx_skb(sdata, skb);
236 }
237 
238 void ieee80211_process_measurement_req(struct ieee80211_sub_if_data *sdata,
239 				       struct ieee80211_mgmt *mgmt,
240 				       size_t len)
241 {
242 	/*
243 	 * Ignoring measurement request is spec violation.
244 	 * Mandatory measurements must be reported optional
245 	 * measurements might be refused or reported incapable
246 	 * For now just refuse
247 	 * TODO: Answer basic measurement as unmeasured
248 	 */
249 	ieee80211_send_refuse_measurement_request(sdata,
250 			&mgmt->u.action.u.measurement.msr_elem,
251 			mgmt->sa, mgmt->bssid,
252 			mgmt->u.action.u.measurement.dialog_token);
253 }
254