1/*
2 * OCB mode implementation
3 *
4 * Copyright: (c) 2014 Czech Technical University in Prague
5 *            (c) 2014 Volkswagen Group Research
6 * Author:    Rostislav Lisovy <rostislav.lisovy@fel.cvut.cz>
7 * Funded by: Volkswagen Group Research
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13
14#include <linux/delay.h>
15#include <linux/if_ether.h>
16#include <linux/skbuff.h>
17#include <linux/if_arp.h>
18#include <linux/etherdevice.h>
19#include <linux/rtnetlink.h>
20#include <net/mac80211.h>
21#include <asm/unaligned.h>
22
23#include "ieee80211_i.h"
24#include "driver-ops.h"
25#include "rate.h"
26
27#define IEEE80211_OCB_HOUSEKEEPING_INTERVAL		(60 * HZ)
28#define IEEE80211_OCB_PEER_INACTIVITY_LIMIT		(240 * HZ)
29#define IEEE80211_OCB_MAX_STA_ENTRIES			128
30
31/**
32 * enum ocb_deferred_task_flags - mac80211 OCB deferred tasks
33 * @OCB_WORK_HOUSEKEEPING: run the periodic OCB housekeeping tasks
34 *
35 * These flags are used in @wrkq_flags field of &struct ieee80211_if_ocb
36 */
37enum ocb_deferred_task_flags {
38	OCB_WORK_HOUSEKEEPING,
39};
40
41void ieee80211_ocb_rx_no_sta(struct ieee80211_sub_if_data *sdata,
42			     const u8 *bssid, const u8 *addr,
43			     u32 supp_rates)
44{
45	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
46	struct ieee80211_local *local = sdata->local;
47	struct ieee80211_chanctx_conf *chanctx_conf;
48	struct ieee80211_supported_band *sband;
49	enum nl80211_bss_scan_width scan_width;
50	struct sta_info *sta;
51	int band;
52
53	/* XXX: Consider removing the least recently used entry and
54	 *      allow new one to be added.
55	 */
56	if (local->num_sta >= IEEE80211_OCB_MAX_STA_ENTRIES) {
57		net_info_ratelimited("%s: No room for a new OCB STA entry %pM\n",
58				     sdata->name, addr);
59		return;
60	}
61
62	ocb_dbg(sdata, "Adding new OCB station %pM\n", addr);
63
64	rcu_read_lock();
65	chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
66	if (WARN_ON_ONCE(!chanctx_conf)) {
67		rcu_read_unlock();
68		return;
69	}
70	band = chanctx_conf->def.chan->band;
71	scan_width = cfg80211_chandef_to_scan_width(&chanctx_conf->def);
72	rcu_read_unlock();
73
74	sta = sta_info_alloc(sdata, addr, GFP_ATOMIC);
75	if (!sta)
76		return;
77
78	sta->last_rx = jiffies;
79
80	/* Add only mandatory rates for now */
81	sband = local->hw.wiphy->bands[band];
82	sta->sta.supp_rates[band] =
83		ieee80211_mandatory_rates(sband, scan_width);
84
85	spin_lock(&ifocb->incomplete_lock);
86	list_add(&sta->list, &ifocb->incomplete_stations);
87	spin_unlock(&ifocb->incomplete_lock);
88	ieee80211_queue_work(&local->hw, &sdata->work);
89}
90
91static struct sta_info *ieee80211_ocb_finish_sta(struct sta_info *sta)
92	__acquires(RCU)
93{
94	struct ieee80211_sub_if_data *sdata = sta->sdata;
95	u8 addr[ETH_ALEN];
96
97	memcpy(addr, sta->sta.addr, ETH_ALEN);
98
99	ocb_dbg(sdata, "Adding new IBSS station %pM (dev=%s)\n",
100		addr, sdata->name);
101
102	sta_info_move_state(sta, IEEE80211_STA_AUTH);
103	sta_info_move_state(sta, IEEE80211_STA_ASSOC);
104	sta_info_move_state(sta, IEEE80211_STA_AUTHORIZED);
105
106	rate_control_rate_init(sta);
107
108	/* If it fails, maybe we raced another insertion? */
109	if (sta_info_insert_rcu(sta))
110		return sta_info_get(sdata, addr);
111	return sta;
112}
113
114static void ieee80211_ocb_housekeeping(struct ieee80211_sub_if_data *sdata)
115{
116	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
117
118	ocb_dbg(sdata, "Running ocb housekeeping\n");
119
120	ieee80211_sta_expire(sdata, IEEE80211_OCB_PEER_INACTIVITY_LIMIT);
121
122	mod_timer(&ifocb->housekeeping_timer,
123		  round_jiffies(jiffies + IEEE80211_OCB_HOUSEKEEPING_INTERVAL));
124}
125
126void ieee80211_ocb_work(struct ieee80211_sub_if_data *sdata)
127{
128	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
129	struct sta_info *sta;
130
131	if (ifocb->joined != true)
132		return;
133
134	sdata_lock(sdata);
135
136	spin_lock_bh(&ifocb->incomplete_lock);
137	while (!list_empty(&ifocb->incomplete_stations)) {
138		sta = list_first_entry(&ifocb->incomplete_stations,
139				       struct sta_info, list);
140		list_del(&sta->list);
141		spin_unlock_bh(&ifocb->incomplete_lock);
142
143		ieee80211_ocb_finish_sta(sta);
144		rcu_read_unlock();
145		spin_lock_bh(&ifocb->incomplete_lock);
146	}
147	spin_unlock_bh(&ifocb->incomplete_lock);
148
149	if (test_and_clear_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags))
150		ieee80211_ocb_housekeeping(sdata);
151
152	sdata_unlock(sdata);
153}
154
155static void ieee80211_ocb_housekeeping_timer(unsigned long data)
156{
157	struct ieee80211_sub_if_data *sdata = (void *)data;
158	struct ieee80211_local *local = sdata->local;
159	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
160
161	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
162
163	ieee80211_queue_work(&local->hw, &sdata->work);
164}
165
166void ieee80211_ocb_setup_sdata(struct ieee80211_sub_if_data *sdata)
167{
168	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
169
170	setup_timer(&ifocb->housekeeping_timer,
171		    ieee80211_ocb_housekeeping_timer,
172		    (unsigned long)sdata);
173	INIT_LIST_HEAD(&ifocb->incomplete_stations);
174	spin_lock_init(&ifocb->incomplete_lock);
175}
176
177int ieee80211_ocb_join(struct ieee80211_sub_if_data *sdata,
178		       struct ocb_setup *setup)
179{
180	struct ieee80211_local *local = sdata->local;
181	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
182	u32 changed = BSS_CHANGED_OCB;
183	int err;
184
185	if (ifocb->joined == true)
186		return -EINVAL;
187
188	sdata->flags |= IEEE80211_SDATA_OPERATING_GMODE;
189	sdata->smps_mode = IEEE80211_SMPS_OFF;
190	sdata->needed_rx_chains = sdata->local->rx_chains;
191
192	mutex_lock(&sdata->local->mtx);
193	err = ieee80211_vif_use_channel(sdata, &setup->chandef,
194					IEEE80211_CHANCTX_SHARED);
195	mutex_unlock(&sdata->local->mtx);
196	if (err)
197		return err;
198
199	ieee80211_bss_info_change_notify(sdata, changed);
200
201	ifocb->joined = true;
202
203	set_bit(OCB_WORK_HOUSEKEEPING, &ifocb->wrkq_flags);
204	ieee80211_queue_work(&local->hw, &sdata->work);
205
206	netif_carrier_on(sdata->dev);
207	return 0;
208}
209
210int ieee80211_ocb_leave(struct ieee80211_sub_if_data *sdata)
211{
212	struct ieee80211_if_ocb *ifocb = &sdata->u.ocb;
213	struct ieee80211_local *local = sdata->local;
214	struct sta_info *sta;
215
216	ifocb->joined = false;
217	sta_info_flush(sdata);
218
219	spin_lock_bh(&ifocb->incomplete_lock);
220	while (!list_empty(&ifocb->incomplete_stations)) {
221		sta = list_first_entry(&ifocb->incomplete_stations,
222				       struct sta_info, list);
223		list_del(&sta->list);
224		spin_unlock_bh(&ifocb->incomplete_lock);
225
226		sta_info_free(local, sta);
227		spin_lock_bh(&ifocb->incomplete_lock);
228	}
229	spin_unlock_bh(&ifocb->incomplete_lock);
230
231	netif_carrier_off(sdata->dev);
232	clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state);
233	ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_OCB);
234
235	mutex_lock(&sdata->local->mtx);
236	ieee80211_vif_release_channel(sdata);
237	mutex_unlock(&sdata->local->mtx);
238
239	skb_queue_purge(&sdata->skb_queue);
240
241	del_timer_sync(&sdata->u.ocb.housekeeping_timer);
242	/* If the timer fired while we waited for it, it will have
243	 * requeued the work. Now the work will be running again
244	 * but will not rearm the timer again because it checks
245	 * whether we are connected to the network or not -- at this
246	 * point we shouldn't be anymore.
247	 */
248
249	return 0;
250}
251