1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * OCB mode implementation
4  *
5  * Copyright: (c) 2014 Czech Technical University in Prague
6  *            (c) 2014 Volkswagen Group Research
7  * Author:    Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
8  * Funded by: Volkswagen Group Research
9  */
10 
11 #include <linux/delay.h>
12 #include <linux/if_ether.h>
13 #include <linux/skbuff.h>
14 #include <linux/if_arp.h>
15 #include <linux/etherdevice.h>
16 #include <linux/rtnetlink.h>
17 #include <net/mac80211.h>
18 #include <asm/unaligned.h>
19 
20 #include "ieee80211_i.h"
21 #include "driver-ops.h"
22 #include "rate.h"
23 
24 #define IEEE80211_OCB_HOUSEKEEPING_INTERVAL		(60 * HZ)
25 #define IEEE80211_OCB_PEER_INACTIVITY_LIMIT		(240 * HZ)
26 #define IEEE80211_OCB_MAX_STA_ENTRIES			128
27 
28 /**
29  * enum ocb_deferred_task_flags - mac80211 OCB deferred tasks
30  * @OCB_WORK_HOUSEKEEPING: run the periodic OCB housekeeping tasks
31  *
32  * These flags are used in @wrkq_flags field of &struct ieee80211_if_ocb
33  */
34 enum ocb_deferred_task_flags {
35 	OCB_WORK_HOUSEKEEPING,
36 };
37 
ieee80211_ocb_rx_no_sta(struct ieee80211_sub_if_data * sdata,const u8 * bssid,const u8 * addr,u32 supp_rates)38 void ieee80211_ocb_rx_no_sta(struct ieee80211_sub_if_data *sdata,
39 			     const u8 *bssid, const u8 *addr,
40 			     u32 supp_rates)
41 {
42 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
43 	struct ieee80211_local *local = sdata->local;
44 	struct ieee80211_chanctx_conf *chanctx_conf;
45 	struct ieee80211_supported_band *sband;
46 	enum nl80211_bss_scan_width scan_width;
47 	struct sta_info *sta;
48 	int band;
49 
50 	/* XXX: Consider removing the least recently used entry and
51 	 *      allow new one to be added.
52 	 */
53 	if (local->num_sta >= IEEE80211_OCB_MAX_STA_ENTRIES) {
54 		net_info_ratelimited("%s: No room for a new OCB STA entry %pM\n",
55 				     sdata->name, addr);
56 		return;
57 	}
58 
59 	ocb_dbg(sdata, "Adding new OCB station %pM\n", addr);
60 
61 	rcu_read_lock();
62 	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
63 	if (WARN_ON_ONCE(!chanctx_conf)) {
64 		rcu_read_unlock();
65 		return;
66 	}
67 	band = chanctx_conf->def.chan->band;
68 	scan_width = cfg80211_chandef_to_scan_width(&chanctx_conf->def);
69 	rcu_read_unlock();
70 
71 	sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
72 	if (!sta)
73 		return;
74 
75 	/* Add only mandatory rates for now */
76 	sband = local->hw.wiphy->bands[band];
77 	sta->sta.supp_rates[band] =
78 		ieee80211_mandatory_rates(sband, scan_width);
79 
80 	spin_lock(&ifocb->incomplete_lock);
81 	list_add(&sta->list, &ifocb->incomplete_stations);
82 	spin_unlock(&ifocb->incomplete_lock);
83 	ieee80211_queue_work(&local->hw, &sdata->work);
84 }
85 
ieee80211_ocb_finish_sta(struct sta_info * sta)86 static struct sta_info *ieee80211_ocb_finish_sta(struct sta_info *sta)
87 	__acquires(RCU)
88 {
89 	struct ieee80211_sub_if_data *sdata = sta->sdata;
90 	u8 addr[ETH_ALEN];
91 
92 	memcpy(addr, sta->sta.addr, ETH_ALEN);
93 
94 	ocb_dbg(sdata, "Adding new IBSS station %pM (dev=%s)\n",
95 		addr, sdata->name);
96 
97 	sta_info_move_state(sta, IEEE80211_STA_AUTH);
98 	sta_info_move_state(sta, IEEE80211_STA_ASSOC);
99 	sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
100 
101 	rate_control_rate_init(sta);
102 
103 	/* If it fails, maybe we raced another insertion? */
104 	if (sta_info_insert_rcu(sta))
105 		return sta_info_get(sdata, addr);
106 	return sta;
107 }
108 
ieee80211_ocb_housekeeping(struct ieee80211_sub_if_data * sdata)109 static void ieee80211_ocb_housekeeping(struct ieee80211_sub_if_data *sdata)
110 {
111 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
112 
113 	ocb_dbg(sdata, "Running ocb housekeeping\n");
114 
115 	ieee80211_sta_expire(sdata, IEEE80211_OCB_PEER_INACTIVITY_LIMIT);
116 
117 	mod_timer(&ifocb->housekeeping_timer,
118 		  round_jiffies(jiffies + IEEE80211_OCB_HOUSEKEEPING_INTERVAL));
119 }
120 
ieee80211_ocb_work(struct ieee80211_sub_if_data * sdata)121 void ieee80211_ocb_work(struct ieee80211_sub_if_data *sdata)
122 {
123 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
124 	struct sta_info *sta;
125 
126 	if (ifocb->joined != true)
127 		return;
128 
129 	sdata_lock(sdata);
130 
131 	spin_lock_bh(&ifocb->incomplete_lock);
132 	while (!list_empty(&ifocb->incomplete_stations)) {
133 		sta = list_first_entry(&ifocb->incomplete_stations,
134 				       struct sta_info, list);
135 		list_del(&sta->list);
136 		spin_unlock_bh(&ifocb->incomplete_lock);
137 
138 		ieee80211_ocb_finish_sta(sta);
139 		rcu_read_unlock();
140 		spin_lock_bh(&ifocb->incomplete_lock);
141 	}
142 	spin_unlock_bh(&ifocb->incomplete_lock);
143 
144 	if (test_and_clear_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags))
145 		ieee80211_ocb_housekeeping(sdata);
146 
147 	sdata_unlock(sdata);
148 }
149 
ieee80211_ocb_housekeeping_timer(struct timer_list * t)150 static void ieee80211_ocb_housekeeping_timer(struct timer_list *t)
151 {
152 	struct ieee80211_sub_if_data *sdata =
153 		from_timer(sdata, t, u.ocb.housekeeping_timer);
154 	struct ieee80211_local *local = sdata->local;
155 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
156 
157 	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
158 
159 	ieee80211_queue_work(&local->hw, &sdata->work);
160 }
161 
ieee80211_ocb_setup_sdata(struct ieee80211_sub_if_data * sdata)162 void ieee80211_ocb_setup_sdata(struct ieee80211_sub_if_data *sdata)
163 {
164 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
165 
166 	timer_setup(&ifocb->housekeeping_timer,
167 		    ieee80211_ocb_housekeeping_timer, 0);
168 	INIT_LIST_HEAD(&ifocb->incomplete_stations);
169 	spin_lock_init(&ifocb->incomplete_lock);
170 }
171 
ieee80211_ocb_join(struct ieee80211_sub_if_data * sdata,struct ocb_setup * setup)172 int ieee80211_ocb_join(struct ieee80211_sub_if_data *sdata,
173 		       struct ocb_setup *setup)
174 {
175 	struct ieee80211_local *local = sdata->local;
176 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
177 	u32 changed = BSS_CHANGED_OCB | BSS_CHANGED_BSSID;
178 	int err;
179 
180 	if (ifocb->joined == true)
181 		return -EINVAL;
182 
183 	sdata->flags |= IEEE80211_SDATA_OPERATING_GMODE;
184 	sdata->smps_mode = IEEE80211_SMPS_OFF;
185 	sdata->needed_rx_chains = sdata->local->rx_chains;
186 
187 	mutex_lock(&sdata->local->mtx);
188 	err = ieee80211_vif_use_channel(sdata, &setup->chandef,
189 					IEEE80211_CHANCTX_SHARED);
190 	mutex_unlock(&sdata->local->mtx);
191 	if (err)
192 		return err;
193 
194 	ieee80211_bss_info_change_notify(sdata, changed);
195 
196 	ifocb->joined = true;
197 
198 	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
199 	ieee80211_queue_work(&local->hw, &sdata->work);
200 
201 	netif_carrier_on(sdata->dev);
202 	return 0;
203 }
204 
ieee80211_ocb_leave(struct ieee80211_sub_if_data * sdata)205 int ieee80211_ocb_leave(struct ieee80211_sub_if_data *sdata)
206 {
207 	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
208 	struct ieee80211_local *local = sdata->local;
209 	struct sta_info *sta;
210 
211 	ifocb->joined = false;
212 	sta_info_flush(sdata);
213 
214 	spin_lock_bh(&ifocb->incomplete_lock);
215 	while (!list_empty(&ifocb->incomplete_stations)) {
216 		sta = list_first_entry(&ifocb->incomplete_stations,
217 				       struct sta_info, list);
218 		list_del(&sta->list);
219 		spin_unlock_bh(&ifocb->incomplete_lock);
220 
221 		sta_info_free(local, sta);
222 		spin_lock_bh(&ifocb->incomplete_lock);
223 	}
224 	spin_unlock_bh(&ifocb->incomplete_lock);
225 
226 	netif_carrier_off(sdata->dev);
227 	clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
228 	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_OCB);
229 
230 	mutex_lock(&sdata->local->mtx);
231 	ieee80211_vif_release_channel(sdata);
232 	mutex_unlock(&sdata->local->mtx);
233 
234 	skb_queue_purge(&sdata->skb_queue);
235 
236 	del_timer_sync(&sdata->u.ocb.housekeeping_timer);
237 	/* If the timer fired while we waited for it, it will have
238 	 * requeued the work. Now the work will be running again
239 	 * but will not rearm the timer again because it checks
240 	 * whether we are connected to the network or not -- at this
241 	 * point we shouldn't be anymore.
242 	 */
243 
244 	return 0;
245 }
246