Return-path: Received: from cora.hrz.tu-chemnitz.de ([134.109.228.40]:56005 "EHLO cora.hrz.tu-chemnitz.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755885Ab3GKOJU (ORCPT ); Thu, 11 Jul 2013 10:09:20 -0400 From: Simon Wunderlich To: Johannes Berg Cc: linux-wireless@vger.kernel.org, Mathias Kretschmer , Simon Wunderlich Subject: [PATCHv5 3/4] mac80211: add channel switch command and beacon callbacks Date: Thu, 11 Jul 2013 16:09:07 +0200 Message-Id: <1373551749-5107-4-git-send-email-siwu@hrz.tu-chemnitz.de> (sfid-20130711_160940_472999_D487C4CF) In-Reply-To: <1373551749-5107-1-git-send-email-siwu@hrz.tu-chemnitz.de> References: <1373551749-5107-1-git-send-email-siwu@hrz.tu-chemnitz.de> Sender: linux-wireless-owner@vger.kernel.org List-ID: The count field in CSA must be decremented with each beacon transmitted. This patch implements the functionality for drivers using ieee80211_beacon_get(). Other drivers must call back manually after reaching count == 0. This patch also contains the handling and finish worker for the channel switch command, and mac80211/chanctx code to allow to change a channel definition of an active channel context. Signed-off-by: Simon Wunderlich Signed-off-by: Mathias Kretschmer --- Changes to PATCHv4: * squashed the patch "allow chanctx to change channels", as this now checks for csa_active * add comment that the chanctx channel change is designed for CSA only * remove BSS_CHANGED_CHANNEL * remove check for use_chanctx * fix rcu_read_lock leak * set csa_active to false after completing callback Changes to PATCHv3: * forbid adding interfaces while CSA is running * forbid calling CSA multiple times * check for multiple channel contexts * abort channel switch when going down while doing CSA Changes to PATCHv2: * fix documentation and style stuff * update tracing * change csa_active to bool * check if csa_active when assigning beacons * fix locking and access * use new ieee80211_vif_change_channel to change the channel Changes to PATCHv1: * don't switch when CAC is active * add hw to parameters for driver Changes to RFCv1: * use beacons as supplied from nl80211 without generating/parsing them * update beacons using offsets * report back by calling the channel switch event in cfg80211 --- include/net/mac80211.h | 36 +++++++++++++ net/mac80211/cfg.c | 129 +++++++++++++++++++++++++++++++++++++++++++- net/mac80211/chan.c | 58 ++++++++++++++++++++ net/mac80211/driver-ops.h | 13 +++++ net/mac80211/ieee80211_i.h | 18 +++++++ net/mac80211/iface.c | 9 ++++ net/mac80211/trace.h | 26 +++++++++ net/mac80211/tx.c | 78 +++++++++++++++++++++++++++ 8 files changed, 365 insertions(+), 2 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 3124036..cb0c94f 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -152,11 +152,13 @@ struct ieee80211_low_level_stats { * @IEEE80211_CHANCTX_CHANGE_WIDTH: The channel width changed * @IEEE80211_CHANCTX_CHANGE_RX_CHAINS: The number of RX chains changed * @IEEE80211_CHANCTX_CHANGE_RADAR: radar detection flag changed + * @IEEE80211_CHANCTX_CHANGE_CHANNEL: switched to another operating channel */ enum ieee80211_chanctx_change { IEEE80211_CHANCTX_CHANGE_WIDTH = BIT(0), IEEE80211_CHANCTX_CHANGE_RX_CHAINS = BIT(1), IEEE80211_CHANCTX_CHANGE_RADAR = BIT(2), + IEEE80211_CHANCTX_CHANGE_CHANNEL = BIT(3) }; /** @@ -1084,6 +1086,7 @@ enum ieee80211_vif_flags { * @addr: address of this interface * @p2p: indicates whether this AP or STA interface is a p2p * interface, i.e. a GO or p2p-sta respectively + * @csa_active: marks whether a channel switch is going on * @driver_flags: flags/capabilities the driver has for this interface, * these need to be set (or cleared) when the interface is added * or, if supported by the driver, the interface type is changed @@ -1106,6 +1109,7 @@ struct ieee80211_vif { struct ieee80211_bss_conf bss_conf; u8 addr[ETH_ALEN]; bool p2p; + bool csa_active; u8 cab_queue; u8 hw_queue[IEEE80211_NUM_ACS]; @@ -2637,6 +2641,16 @@ enum ieee80211_roc_type { * @ipv6_addr_change: IPv6 address assignment on the given interface changed. * Currently, this is only called for managed or P2P client interfaces. * This callback is optional; it must not sleep. + * + * @channel_switch_beacon: Starts a channel switch to a new channel. + * Beacons are modified to include CSA or ECSA IEs before calling this + * function. The corresponding count fields in these IEs must be + * decremented, and when they reach zero the driver must call + * ieee80211_csa_finish(). Drivers which use ieee80211_beacon_get() + * get the csa counter decremented by mac80211, but must check if it is + * zero using ieee80211_csa_is_complete() after the beacon has been + * transmitted and then call ieee80211_csa_finish(). + * */ struct ieee80211_ops { void (*tx)(struct ieee80211_hw *hw, @@ -2824,6 +2838,9 @@ struct ieee80211_ops { struct ieee80211_vif *vif, struct inet6_dev *idev); #endif + void (*channel_switch_beacon)(struct ieee80211_hw *hw, + struct ieee80211_vif *vif, + struct cfg80211_chan_def *chandef); }; /** @@ -3319,6 +3336,25 @@ static inline struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw, } /** + * ieee80211_csa_finish - notify mac80211 about channel switch + * @vif: &struct ieee80211_vif pointer from the add_interface callback. + * + * After a channel switch announcement was scheduled and the counter in this + * announcement hit zero, this function must be called by the driver to + * notify mac80211 that the channel can be changed. + */ +void ieee80211_csa_finish(struct ieee80211_vif *vif); + +/** + * ieee80211_csa_is_complete - find out if counters reached zero + * @vif: &struct ieee80211_vif pointer from the add_interface callback. + * + * This function returns whether the channel switch counters reached zero. + */ +bool ieee80211_csa_is_complete(struct ieee80211_vif *vif); + + +/** * ieee80211_proberesp_get - retrieve a Probe Response template * @hw: pointer obtained from ieee80211_alloc_hw(). * @vif: &struct ieee80211_vif pointer from the add_interface callback. diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c index 8e6c935..e3f598bd 100644 --- a/net/mac80211/cfg.c +++ b/net/mac80211/cfg.c @@ -860,8 +860,8 @@ static int ieee80211_set_probe_resp(struct ieee80211_sub_if_data *sdata, return 0; } -static int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata, - struct cfg80211_beacon_data *params) +int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata, + struct cfg80211_beacon_data *params) { struct beacon_data *new, *old; int new_head_len, new_tail_len; @@ -1024,6 +1024,12 @@ static int ieee80211_change_beacon(struct wiphy *wiphy, struct net_device *dev, sdata = IEEE80211_DEV_TO_SUB_IF(dev); + /* don't allow changing the beacon while CSA is in place - offset + * of channel switch counter may change + */ + if (sdata->vif.csa_active) + return -EBUSY; + old = rtnl_dereference(sdata->u.ap.beacon); if (!old) return -ENOENT; @@ -1048,6 +1054,10 @@ static int ieee80211_stop_ap(struct wiphy *wiphy, struct net_device *dev) return -ENOENT; old_probe_resp = rtnl_dereference(sdata->u.ap.probe_resp); + /* abort any running channel switch */ + sdata->vif.csa_active = false; + cancel_work_sync(&sdata->csa_finalize_work); + /* turn off carrier for this interface and dependent VLANs */ list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) netif_carrier_off(vlan->dev); @@ -2831,6 +2841,120 @@ cfg80211_beacon_dup(struct cfg80211_beacon_data *beacon) return new_beacon; } +void ieee80211_csa_finalize_work(struct work_struct *work) +{ + struct ieee80211_sub_if_data *sdata = + container_of(work, struct ieee80211_sub_if_data, + csa_finalize_work); + struct ieee80211_local *local = sdata->local; + int err, changed; + + if (!ieee80211_sdata_running(sdata)) + return; + + if (WARN_ON(sdata->vif.type != NL80211_IFTYPE_AP)) + return; + + sdata->radar_required = sdata->csa_radar_required; + err = ieee80211_vif_change_channel(sdata, &local->csa_chandef, + &changed); + if (WARN_ON(err < 0)) + return; + + err = ieee80211_assign_beacon(sdata, sdata->u.ap.next_beacon); + if (err < 0) + return; + + changed |= err; + kfree(sdata->u.ap.next_beacon); + sdata->u.ap.next_beacon = NULL; + sdata->vif.csa_active = false; + + ieee80211_wake_queues_by_reason(&sdata->local->hw, + IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_CSA); + + ieee80211_bss_info_change_notify(sdata, changed); + + cfg80211_ch_switch_notify(sdata->dev, &local->csa_chandef); +} + +static int ieee80211_channel_switch(struct wiphy *wiphy, struct net_device *dev, + struct cfg80211_csa_settings *params) +{ + struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev); + struct ieee80211_local *local = sdata->local; + struct ieee80211_chanctx_conf *chanctx_conf; + struct ieee80211_chanctx *chanctx; + int err, num_chanctx; + + if (!list_empty(&local->roc_list) || local->scanning) + return -EBUSY; + + if (sdata->wdev.cac_started) + return -EBUSY; + + rcu_read_lock(); + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); + if (!chanctx_conf) { + rcu_read_unlock(); + return -EBUSY; + } + + /* don't handle for multi-VIF cases */ + chanctx = container_of(chanctx_conf, struct ieee80211_chanctx, conf); + if (chanctx->refcount > 1) { + rcu_read_unlock(); + return -EBUSY; + } + num_chanctx = 0; + list_for_each_entry_rcu(chanctx, &local->chanctx_list, list) + num_chanctx++; + + if (num_chanctx > 1) { + rcu_read_unlock(); + return -EBUSY; + } + rcu_read_unlock(); + + /* don't allow another channel switch if one is already active. */ + if (sdata->vif.csa_active) + return -EBUSY; + + /* only handle AP for now. */ + switch (sdata->vif.type) { + case NL80211_IFTYPE_AP: + break; + default: + return -EOPNOTSUPP; + } + + sdata->u.ap.next_beacon = cfg80211_beacon_dup(¶ms->beacon_after); + if (!sdata->u.ap.next_beacon) + return -ENOMEM; + + sdata->csa_counter_offset_beacon = params->counter_offset_beacon; + sdata->csa_counter_offset_presp = params->counter_offset_presp; + sdata->csa_radar_required = params->radar_required; + + if (params->block_tx) + ieee80211_stop_queues_by_reason(&local->hw, + IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_CSA); + + err = ieee80211_assign_beacon(sdata, ¶ms->beacon_csa); + if (err < 0) + return err; + + local->csa_chandef = params->chandef; + sdata->vif.csa_active = true; + + ieee80211_bss_info_change_notify(sdata, err); + drv_channel_switch_beacon(sdata, ¶ms->chandef); + + return 0; +} + static int ieee80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev, struct ieee80211_channel *chan, bool offchan, unsigned int wait, const u8 *buf, size_t len, @@ -3548,4 +3672,5 @@ struct cfg80211_ops mac80211_config_ops = { .get_et_strings = ieee80211_get_et_strings, .get_channel = ieee80211_cfg_get_channel, .start_radar_detection = ieee80211_start_radar_detection, + .channel_switch = ieee80211_channel_switch, }; diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 03e8d2e..3a4764b 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -410,6 +410,64 @@ int ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata, return ret; } +int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata, + const struct cfg80211_chan_def *chandef, + u32 *changed) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_chanctx_conf *conf; + struct ieee80211_chanctx *ctx; + int ret; + u32 chanctx_changed = 0; + + /* should never be called if not performing a channel switch. */ + if (WARN_ON(!sdata->vif.csa_active)) + return -EINVAL; + + if (!cfg80211_chandef_usable(sdata->local->hw.wiphy, chandef, + IEEE80211_CHAN_DISABLED)) + return -EINVAL; + + mutex_lock(&local->chanctx_mtx); + conf = rcu_dereference_protected(sdata->vif.chanctx_conf, + lockdep_is_held(&local->chanctx_mtx)); + if (!conf) { + ret = -EINVAL; + goto out; + } + + ctx = container_of(conf, struct ieee80211_chanctx, conf); + if (ctx->refcount != 1) { + ret = -EINVAL; + goto out; + } + + if (sdata->vif.bss_conf.chandef.width != chandef->width) { + chanctx_changed = IEEE80211_CHANCTX_CHANGE_WIDTH; + *changed |= BSS_CHANGED_BANDWIDTH; + } + + sdata->vif.bss_conf.chandef = *chandef; + ctx->conf.def = *chandef; + + chanctx_changed |= IEEE80211_CHANCTX_CHANGE_CHANNEL; + drv_change_chanctx(local, ctx, chanctx_changed); + + if (!local->use_chanctx) { + local->_oper_chandef = *chandef; + ieee80211_hw_config(local, 0); + } + + ieee80211_recalc_chanctx_chantype(local, ctx); + ieee80211_recalc_smps_chanctx(local, ctx); + ieee80211_recalc_radar_chanctx(local, ctx); + + ret = 0; + out: + mutex_unlock(&local->chanctx_mtx); + return ret; +} + int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata, const struct cfg80211_chan_def *chandef, u32 *changed) diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h index b931c96..b3ea11f 100644 --- a/net/mac80211/driver-ops.h +++ b/net/mac80211/driver-ops.h @@ -1072,4 +1072,17 @@ static inline void drv_ipv6_addr_change(struct ieee80211_local *local, } #endif +static inline void +drv_channel_switch_beacon(struct ieee80211_sub_if_data *sdata, + struct cfg80211_chan_def *chandef) +{ + struct ieee80211_local *local = sdata->local; + + if (local->ops->channel_switch_beacon) { + trace_drv_channel_switch_beacon(local, sdata, chandef); + local->ops->channel_switch_beacon(&local->hw, &sdata->vif, + chandef); + } +} + #endif /* __MAC80211_DRIVER_OPS */ diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 23a191b..31ca8d2 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -259,6 +259,8 @@ struct ieee80211_if_ap { struct beacon_data __rcu *beacon; struct probe_resp __rcu *probe_resp; + /* to be used after channel switch. */ + struct cfg80211_beacon_data *next_beacon; struct list_head vlans; struct ps_data ps; @@ -716,6 +718,11 @@ struct ieee80211_sub_if_data { struct ieee80211_tx_queue_params tx_conf[IEEE80211_NUM_ACS]; + struct work_struct csa_finalize_work; + int csa_counter_offset_beacon; + int csa_counter_offset_presp; + bool csa_radar_required; + /* used to reconfigure hardware SM PS */ struct work_struct recalc_smps; @@ -1373,6 +1380,9 @@ void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc, bool free); void ieee80211_sw_roc_work(struct work_struct *work); void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc); +/* channel switch handling */ +void ieee80211_csa_finalize_work(struct work_struct *work); + /* interface handling */ int ieee80211_iface_init(void); void ieee80211_iface_exit(void); @@ -1394,6 +1404,9 @@ void ieee80211_del_virtual_monitor(struct ieee80211_local *local); bool __ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata); void ieee80211_recalc_txpower(struct ieee80211_sub_if_data *sdata); +int ieee80211_assign_beacon(struct ieee80211_sub_if_data *sdata, + struct cfg80211_beacon_data *params); + static inline bool ieee80211_sdata_running(struct ieee80211_sub_if_data *sdata) { @@ -1658,6 +1671,11 @@ int __must_check ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata, const struct cfg80211_chan_def *chandef, u32 *changed); +/* NOTE: only use ieee80211_vif_change_channel() for channel switch */ +int __must_check +ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata, + const struct cfg80211_chan_def *chandef, + u32 *changed); void ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata); void ieee80211_vif_vlan_copy_chanctx(struct ieee80211_sub_if_data *sdata); void ieee80211_vif_copy_chanctx_to_vlans(struct ieee80211_sub_if_data *sdata, diff --git a/net/mac80211/iface.c b/net/mac80211/iface.c index 093c34a..187c161 100644 --- a/net/mac80211/iface.c +++ b/net/mac80211/iface.c @@ -274,6 +274,12 @@ static int ieee80211_check_concurrent_iface(struct ieee80211_sub_if_data *sdata, if (iftype == NL80211_IFTYPE_ADHOC && nsdata->vif.type == NL80211_IFTYPE_ADHOC) return -EBUSY; + /* + * will not add another interface while any channel + * switch is active. + */ + if (nsdata->vif.csa_active) + return -EBUSY; /* * The remaining checks are only performed for interfaces @@ -804,6 +810,8 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, cancel_work_sync(&local->dynamic_ps_enable_work); cancel_work_sync(&sdata->recalc_smps); + sdata->vif.csa_active = false; + cancel_work_sync(&sdata->csa_finalize_work); cancel_delayed_work_sync(&sdata->dfs_cac_timer_work); @@ -1267,6 +1275,7 @@ static void ieee80211_setup_sdata(struct ieee80211_sub_if_data *sdata, skb_queue_head_init(&sdata->skb_queue); INIT_WORK(&sdata->work, ieee80211_iface_work); INIT_WORK(&sdata->recalc_smps, ieee80211_recalc_smps_work); + INIT_WORK(&sdata->csa_finalize_work, ieee80211_csa_finalize_work); switch (type) { case NL80211_IFTYPE_P2P_GO: diff --git a/net/mac80211/trace.h b/net/mac80211/trace.h index c215fafd7..1aba645 100644 --- a/net/mac80211/trace.h +++ b/net/mac80211/trace.h @@ -1906,6 +1906,32 @@ TRACE_EVENT(api_radar_detected, ) ); +TRACE_EVENT(drv_channel_switch_beacon, + TP_PROTO(struct ieee80211_local *local, + struct ieee80211_sub_if_data *sdata, + struct cfg80211_chan_def *chandef), + + TP_ARGS(local, sdata, chandef), + + TP_STRUCT__entry( + LOCAL_ENTRY + VIF_ENTRY + CHANDEF_ENTRY + ), + + TP_fast_assign( + LOCAL_ASSIGN; + VIF_ASSIGN; + CHANDEF_ASSIGN(chandef); + ), + + TP_printk( + LOCAL_PR_FMT VIF_PR_FMT " channel switch to " CHANDEF_PR_FMT, + LOCAL_PR_ARG, VIF_PR_ARG, CHANDEF_PR_ARG + ) +); + + #ifdef CONFIG_MAC80211_MESSAGE_TRACING #undef TRACE_SYSTEM #define TRACE_SYSTEM mac80211_msg diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index f82301b..b66f767 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -2335,6 +2335,81 @@ static int ieee80211_beacon_add_tim(struct ieee80211_sub_if_data *sdata, return 0; } +void ieee80211_csa_finish(struct ieee80211_vif *vif) +{ + struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif); + + ieee80211_queue_work(&sdata->local->hw, + &sdata->csa_finalize_work); +} +EXPORT_SYMBOL(ieee80211_csa_finish); + +static void ieee80211_update_csa(struct ieee80211_sub_if_data *sdata, + struct beacon_data *beacon) +{ + struct probe_resp *resp; + int counter_offset_beacon = sdata->csa_counter_offset_beacon; + int counter_offset_presp = sdata->csa_counter_offset_presp; + + /* warn if the driver did not check for/react to csa completeness */ + if (WARN_ON(((u8 *)beacon->tail)[counter_offset_beacon] == 0)) + return; + + ((u8 *)beacon->tail)[counter_offset_beacon]--; + + if (sdata->vif.type == NL80211_IFTYPE_AP && + counter_offset_presp) { + rcu_read_lock(); + resp = rcu_dereference(sdata->u.ap.probe_resp); + + /* if nl80211 accepted the offset, this should not happen. */ + if (WARN_ON(!resp)) { + rcu_read_unlock(); + return; + } + resp->data[counter_offset_presp]--; + rcu_read_unlock(); + } +} + +bool ieee80211_csa_is_complete(struct ieee80211_vif *vif) +{ + struct ieee80211_sub_if_data *sdata = vif_to_sdata(vif); + struct beacon_data *beacon = NULL; + u8 *beacon_data; + size_t beacon_data_len; + int counter_beacon = sdata->csa_counter_offset_beacon; + int ret = false; + + if (!ieee80211_sdata_running(sdata)) + return false; + + rcu_read_lock(); + if (vif->type == NL80211_IFTYPE_AP) { + struct ieee80211_if_ap *ap = &sdata->u.ap; + + beacon = rcu_dereference(ap->beacon); + if (WARN_ON(!beacon || !beacon->tail)) + goto out; + beacon_data = beacon->tail; + beacon_data_len = beacon->tail_len; + } else { + WARN_ON(1); + goto out; + } + + if (WARN_ON(counter_beacon > beacon_data_len)) + goto out; + + if (beacon_data[counter_beacon] == 0) + ret = true; + out: + rcu_read_unlock(); + + return ret; +} +EXPORT_SYMBOL(ieee80211_csa_is_complete); + struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw, struct ieee80211_vif *vif, u16 *tim_offset, u16 *tim_length) @@ -2365,6 +2440,9 @@ struct sk_buff *ieee80211_beacon_get_tim(struct ieee80211_hw *hw, struct beacon_data *beacon = rcu_dereference(ap->beacon); if (beacon) { + if (sdata->vif.csa_active) + ieee80211_update_csa(sdata, beacon); + /* * headroom, head length, * tail length and maximum TIM length -- 1.7.10.4