1 /* 2 * Off-channel operation helpers 3 * 4 * Copyright 2003, Jouni Malinen <jkmaline@cc.hut.fi> 5 * Copyright 2004, Instant802 Networks, Inc. 6 * Copyright 2005, Devicescape Software, Inc. 7 * Copyright 2006-2007 Jiri Benc <jbenc@suse.cz> 8 * Copyright 2007, Michael Wu <flamingice@sourmilk.net> 9 * Copyright 2009 Johannes Berg <johannes@sipsolutions.net> 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 #include <net/mac80211.h> 16 #include "ieee80211_i.h" 17 18 /* 19 * inform AP that we will go to sleep so that it will buffer the frames 20 * while we scan 21 */ 22 static void ieee80211_offchannel_ps_enable(struct ieee80211_sub_if_data *sdata) 23 { 24 struct ieee80211_local *local = sdata->local; 25 struct ieee80211_if_managed *ifmgd = &sdata->u.mgd; 26 27 local->offchannel_ps_enabled = false; 28 29 /* FIXME: what to do when local->pspolling is true? */ 30 31 del_timer_sync(&local->dynamic_ps_timer); 32 del_timer_sync(&ifmgd->bcn_mon_timer); 33 del_timer_sync(&ifmgd->conn_mon_timer); 34 35 cancel_work_sync(&local->dynamic_ps_enable_work); 36 37 if (local->hw.conf.flags & IEEE80211_CONF_PS) { 38 local->offchannel_ps_enabled = true; 39 local->hw.conf.flags &= ~IEEE80211_CONF_PS; 40 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); 41 } 42 43 if (!(local->offchannel_ps_enabled) || 44 !(local->hw.flags & IEEE80211_HW_PS_NULLFUNC_STACK)) 45 /* 46 * If power save was enabled, no need to send a nullfunc 47 * frame because AP knows that we are sleeping. But if the 48 * hardware is creating the nullfunc frame for power save 49 * status (ie. IEEE80211_HW_PS_NULLFUNC_STACK is not 50 * enabled) and power save was enabled, the firmware just 51 * sent a null frame with power save disabled. So we need 52 * to send a new nullfunc frame to inform the AP that we 53 * are again sleeping. 54 */ 55 ieee80211_send_nullfunc(local, sdata, 1); 56 } 57 58 /* inform AP that we are awake again, unless power save is enabled */ 59 static void ieee80211_offchannel_ps_disable(struct ieee80211_sub_if_data *sdata) 60 { 61 struct ieee80211_local *local = sdata->local; 62 63 if (!local->ps_sdata) 64 ieee80211_send_nullfunc(local, sdata, 0); 65 else if (local->offchannel_ps_enabled) { 66 /* 67 * In !IEEE80211_HW_PS_NULLFUNC_STACK case the hardware 68 * will send a nullfunc frame with the powersave bit set 69 * even though the AP already knows that we are sleeping. 70 * This could be avoided by sending a null frame with power 71 * save bit disabled before enabling the power save, but 72 * this doesn't gain anything. 73 * 74 * When IEEE80211_HW_PS_NULLFUNC_STACK is enabled, no need 75 * to send a nullfunc frame because AP already knows that 76 * we are sleeping, let's just enable power save mode in 77 * hardware. 78 */ 79 local->hw.conf.flags |= IEEE80211_CONF_PS; 80 ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_PS); 81 } else if (local->hw.conf.dynamic_ps_timeout > 0) { 82 /* 83 * If IEEE80211_CONF_PS was not set and the dynamic_ps_timer 84 * had been running before leaving the operating channel, 85 * restart the timer now and send a nullfunc frame to inform 86 * the AP that we are awake. 87 */ 88 ieee80211_send_nullfunc(local, sdata, 0); 89 mod_timer(&local->dynamic_ps_timer, jiffies + 90 msecs_to_jiffies(local->hw.conf.dynamic_ps_timeout)); 91 } 92 93 ieee80211_sta_reset_beacon_monitor(sdata); 94 ieee80211_sta_reset_conn_monitor(sdata); 95 } 96 97 void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local) 98 { 99 struct ieee80211_sub_if_data *sdata; 100 101 mutex_lock(&local->iflist_mtx); 102 list_for_each_entry(sdata, &local->interfaces, list) { 103 if (!ieee80211_sdata_running(sdata)) 104 continue; 105 106 /* disable beaconing */ 107 if (sdata->vif.type == NL80211_IFTYPE_AP || 108 sdata->vif.type == NL80211_IFTYPE_ADHOC || 109 sdata->vif.type == NL80211_IFTYPE_MESH_POINT) 110 ieee80211_bss_info_change_notify( 111 sdata, BSS_CHANGED_BEACON_ENABLED); 112 113 /* 114 * only handle non-STA interfaces here, STA interfaces 115 * are handled in ieee80211_offchannel_stop_station(), 116 * e.g., from the background scan state machine. 117 * 118 * In addition, do not stop monitor interface to allow it to be 119 * used from user space controlled off-channel operations. 120 */ 121 if (sdata->vif.type != NL80211_IFTYPE_STATION && 122 sdata->vif.type != NL80211_IFTYPE_MONITOR) { 123 set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state); 124 netif_tx_stop_all_queues(sdata->dev); 125 } 126 } 127 mutex_unlock(&local->iflist_mtx); 128 } 129 130 void ieee80211_offchannel_stop_station(struct ieee80211_local *local) 131 { 132 struct ieee80211_sub_if_data *sdata; 133 134 /* 135 * notify the AP about us leaving the channel and stop all STA interfaces 136 */ 137 mutex_lock(&local->iflist_mtx); 138 list_for_each_entry(sdata, &local->interfaces, list) { 139 if (!ieee80211_sdata_running(sdata)) 140 continue; 141 142 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 143 set_bit(SDATA_STATE_OFFCHANNEL, &sdata->state); 144 netif_tx_stop_all_queues(sdata->dev); 145 if (sdata->u.mgd.associated) 146 ieee80211_offchannel_ps_enable(sdata); 147 } 148 } 149 mutex_unlock(&local->iflist_mtx); 150 } 151 152 void ieee80211_offchannel_return(struct ieee80211_local *local, 153 bool enable_beaconing) 154 { 155 struct ieee80211_sub_if_data *sdata; 156 157 mutex_lock(&local->iflist_mtx); 158 list_for_each_entry(sdata, &local->interfaces, list) { 159 if (!ieee80211_sdata_running(sdata)) 160 continue; 161 162 /* Tell AP we're back */ 163 if (sdata->vif.type == NL80211_IFTYPE_STATION) { 164 if (sdata->u.mgd.associated) 165 ieee80211_offchannel_ps_disable(sdata); 166 } 167 168 if (sdata->vif.type != NL80211_IFTYPE_MONITOR) { 169 clear_bit(SDATA_STATE_OFFCHANNEL, &sdata->state); 170 /* 171 * This may wake up queues even though the driver 172 * currently has them stopped. This is not very 173 * likely, since the driver won't have gotten any 174 * (or hardly any) new packets while we weren't 175 * on the right channel, and even if it happens 176 * it will at most lead to queueing up one more 177 * packet per queue in mac80211 rather than on 178 * the interface qdisc. 179 */ 180 netif_tx_wake_all_queues(sdata->dev); 181 } 182 183 /* re-enable beaconing */ 184 if (enable_beaconing && 185 (sdata->vif.type == NL80211_IFTYPE_AP || 186 sdata->vif.type == NL80211_IFTYPE_ADHOC || 187 sdata->vif.type == NL80211_IFTYPE_MESH_POINT)) 188 ieee80211_bss_info_change_notify( 189 sdata, BSS_CHANGED_BEACON_ENABLED); 190 } 191 mutex_unlock(&local->iflist_mtx); 192 } 193