mac80211: support remain-on-channel command

This implements the new remain-on-channel cfg80211
command in mac80211, extending the work interface.

Also change the work purge code to be able to clean
up events properly (pretending they timed out.)

Signed-off-by: Jouni Malinen <jouni.malinen@atheros.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

6 files changed, 181 insertions, 6 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index ea862dfc08ed..2e5e841e9b7b 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1441,6 +1441,28 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
         return -EINVAL;
 }
 
+static int ieee80211_remain_on_channel(struct wiphy *wiphy,
+                                       struct net_device *dev,
+                                       struct ieee80211_channel *chan,
+                                       enum nl80211_channel_type channel_type,
+                                       unsigned int duration,
+                                       u64 *cookie)
+{
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+        return ieee80211_wk_remain_on_channel(sdata, chan, channel_type,
+                                              duration, cookie);
+}
+
+static int ieee80211_cancel_remain_on_channel(struct wiphy *wiphy,
+                                              struct net_device *dev,
+                                              u64 cookie)
+{
+        struct ieee80211_sub_if_data *sdata = IEEE80211_DEV_TO_SUB_IF(dev);
+
+        return ieee80211_wk_cancel_remain_on_channel(sdata, cookie);
+}
+
 struct cfg80211_ops mac80211_config_ops = {
         .add_virtual_intf = ieee80211_add_iface,
         .del_virtual_intf = ieee80211_del_iface,
@@ -1487,4 +1509,6 @@ struct cfg80211_ops mac80211_config_ops = {
         CFG80211_TESTMODE_CMD(ieee80211_testmode_cmd)
         .set_power_mgmt = ieee80211_set_power_mgmt,
         .set_bitrate_mask = ieee80211_set_bitrate_mask,
+        .remain_on_channel = ieee80211_remain_on_channel,
+        .cancel_remain_on_channel = ieee80211_cancel_remain_on_channel,
 };
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index fd912eb5309e..23547ebacf3d 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -225,9 +225,11 @@ struct mesh_preq_queue {
 };
 
 enum ieee80211_work_type {
+        IEEE80211_WORK_ABORT,
         IEEE80211_WORK_DIRECT_PROBE,
         IEEE80211_WORK_AUTH,
         IEEE80211_WORK_ASSOC,
+        IEEE80211_WORK_REMAIN_ON_CHANNEL,
 };
 
 /**
@@ -283,6 +285,9 @@ struct ieee80211_work {
                         u8 supp_rates_len;
                         bool wmm_used, use_11n;
                 } assoc;
+                struct {
+                        unsigned long timeout;
+                } remain;
         };
 
         int ie_len;
@@ -729,6 +734,10 @@ struct ieee80211_local {
         enum nl80211_channel_type oper_channel_type;
         struct ieee80211_channel *oper_channel, *csa_channel;
 
+        /* Temporary remain-on-channel for off-channel operations */
+        struct ieee80211_channel *tmp_channel;
+        enum nl80211_channel_type tmp_channel_type;
+
         /* SNMP counters */
         /* dot11CountersTable */
         u32 dot11TransmittedFragmentCount;
@@ -1162,6 +1171,12 @@ void free_work(struct ieee80211_work *wk);
 void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata);
 ieee80211_rx_result ieee80211_work_rx_mgmt(struct ieee80211_sub_if_data *sdata,
                                            struct sk_buff *skb);
+int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
+                                   struct ieee80211_channel *chan,
+                                   enum nl80211_channel_type channel_type,
+                                   unsigned int duration, u64 *cookie);
+int ieee80211_wk_cancel_remain_on_channel(
+        struct ieee80211_sub_if_data *sdata, u64 cookie);
 
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 5fcd3548417e..d0a14d953f08 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -107,6 +107,9 @@ int ieee80211_hw_config(struct ieee80211_local *local, u32 changed)
         if (scan_chan) {
                 chan = scan_chan;
                 channel_type = NL80211_CHAN_NO_HT;
+        } else if (local->tmp_channel) {
+                chan = scan_chan = local->tmp_channel;
+                channel_type = local->tmp_channel_type;
         } else {
                 chan = local->oper_channel;
                 channel_type = local->oper_channel_type;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index e44f1ed0b0da..32d6e6614f9f 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -857,6 +857,9 @@ static void ieee80211_mgd_probe_ap(struct ieee80211_sub_if_data *sdata,
         if (sdata->local->scanning)
                 return;
 
+        if (sdata->local->tmp_channel)
+                return;
+
         mutex_lock(&ifmgd->mtx);
 
         if (!ifmgd->associated)
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 2cd880e444d1..a7bbfc40a648 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -106,9 +106,13 @@ void ieee80211_offchannel_stop_beaconing(struct ieee80211_local *local)
                 /*
                  * only handle non-STA interfaces here, STA interfaces
                  * are handled in ieee80211_offchannel_stop_station(),
-                 * e.g., from the background scan state machine
+                 * e.g., from the background scan state machine.
+                 *
+                 * In addition, do not stop monitor interface to allow it to be
+                 * used from user space controlled off-channel operations.
                  */
-                if (sdata->vif.type != NL80211_IFTYPE_STATION)
+                if (sdata->vif.type != NL80211_IFTYPE_STATION &&
+                    sdata->vif.type != NL80211_IFTYPE_MONITOR)
                         netif_stop_queue(sdata->dev);
         }
         mutex_unlock(&local->iflist_mtx);
diff --git a/net/mac80211/work.c b/net/mac80211/work.c
index 0b8c31c600aa..0acea7cf714a 100644
--- a/net/mac80211/work.c
+++ b/net/mac80211/work.c
@@ -538,6 +538,44 @@ ieee80211_associate(struct ieee80211_work *wk)
         return WORK_ACT_NONE;
 }
 
+static enum work_action __must_check
+ieee80211_remain_on_channel_timeout(struct ieee80211_work *wk)
+{
+        struct ieee80211_sub_if_data *sdata = wk->sdata;
+        struct ieee80211_local *local = sdata->local;
+
+        /*
+         * First time we run, do nothing -- the generic code will
+         * have switched to the right channel etc.
+         */
+        if (wk->timeout != wk->remain.timeout) {
+                wk->timeout = wk->remain.timeout;
+                return WORK_ACT_NONE;
+        }
+
+        /*
+         * We are done serving the remain-on-channel command; kill the work
+         * item to allow idle state to be entered again. In addition, clear the
+         * temporary channel information to allow operational channel to be
+         * used.
+         */
+        list_del(&wk->list);
+        free_work(wk);
+
+        if (local->tmp_channel) {
+                cfg80211_remain_on_channel_expired(sdata->dev, (u64)wk,
+                                                   local->tmp_channel,
+                                                   local->tmp_channel_type,
+                                                   GFP_KERNEL);
+
+                local->tmp_channel = NULL;
+                ieee80211_hw_config(local, IEEE80211_CONF_CHANGE_CHANNEL);
+                ieee80211_offchannel_return(local, true);
+        }
+
+        return WORK_ACT_NONE;
+}
+
 static void ieee80211_auth_challenge(struct ieee80211_work *wk,
                                      struct ieee80211_mgmt *mgmt,
                                      size_t len)
@@ -825,6 +863,8 @@ static void ieee80211_work_work(struct work_struct *work)
                         /* nothing */
                         rma = WORK_ACT_NONE;
                         break;
+                case IEEE80211_WORK_ABORT:
+                        rma = WORK_ACT_TIMEOUT;
                 case IEEE80211_WORK_DIRECT_PROBE:
                         rma = ieee80211_direct_probe(wk);
                         break;
@@ -834,6 +874,9 @@ static void ieee80211_work_work(struct work_struct *work)
                 case IEEE80211_WORK_ASSOC:
                         rma = ieee80211_associate(wk);
                         break;
+                case IEEE80211_WORK_REMAIN_ON_CHANNEL:
+                        rma = ieee80211_remain_on_channel_timeout(wk);
+                        break;
                 }
 
                 switch (rma) {
@@ -900,14 +943,25 @@ void ieee80211_work_init(struct ieee80211_local *local)
 void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata)
 {
         struct ieee80211_local *local = sdata->local;
-        struct ieee80211_work *wk, *tmp;
+        struct ieee80211_work *wk;
 
         mutex_lock(&local->work_mtx);
-        list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
+        list_for_each_entry(wk, &local->work_list, list) {
                 if (wk->sdata != sdata)
                         continue;
-                list_del(&wk->list);
-                free_work(wk);
+                wk->type = IEEE80211_WORK_ABORT;
+        }
+        mutex_unlock(&local->work_mtx);
+
+        /* run cleanups etc. */
+        ieee80211_work_work(&local->work_work);
+
+        mutex_lock(&local->work_mtx);
+        list_for_each_entry(wk, &local->work_list, list) {
+                if (wk->sdata != sdata)
+                        continue;
+                WARN_ON(1);
+                break;
         }
         mutex_unlock(&local->work_mtx);
 }
@@ -949,3 +1003,75 @@ ieee80211_rx_result ieee80211_work_rx_mgmt(struct ieee80211_sub_if_data *sdata,
 
         return RX_CONTINUE;
 }
+
+int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
+                                   struct ieee80211_channel *chan,
+                                   enum nl80211_channel_type channel_type,
+                                   unsigned int duration, u64 *cookie)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_work *wk;
+
+        wk = kzalloc(sizeof(*wk), GFP_KERNEL);
+        if (!wk)
+                return -ENOMEM;
+
+        wk->type = IEEE80211_WORK_REMAIN_ON_CHANNEL;
+        wk->chan = chan;
+        wk->sdata = sdata;
+
+        wk->remain.timeout = jiffies + msecs_to_jiffies(duration);
+
+        *cookie = (u64)wk;
+
+        ieee80211_add_work(wk);
+
+        /*
+         * TODO: could optimize this by leaving the station vifs in awake mode
+         * if they happen to be on the same channel as the requested channel
+         */
+        ieee80211_offchannel_stop_beaconing(local);
+        ieee80211_offchannel_stop_station(local);
+
+        sdata->local->tmp_channel = chan;
+        sdata->local->tmp_channel_type = channel_type;
+        ieee80211_hw_config(sdata->local, IEEE80211_CONF_CHANGE_CHANNEL);
+
+        cfg80211_ready_on_channel(sdata->dev, (u64)wk, chan, channel_type,
+                                  duration, GFP_KERNEL);
+
+        return 0;
+}
+
+int ieee80211_wk_cancel_remain_on_channel(struct ieee80211_sub_if_data *sdata,
+                                          u64 cookie)
+{
+        struct ieee80211_local *local = sdata->local;
+        struct ieee80211_work *wk, *tmp;
+        bool found = false;
+
+        mutex_lock(&local->work_mtx);
+        list_for_each_entry_safe(wk, tmp, &local->work_list, list) {
+                if ((u64)wk == cookie) {
+                        found = true;
+                        list_del(&wk->list);
+                        free_work(wk);
+                        break;
+                }
+        }
+        mutex_unlock(&local->work_mtx);
+
+        if (!found)
+                return -ENOENT;
+
+        if (sdata->local->tmp_channel) {
+                sdata->local->tmp_channel = NULL;
+                ieee80211_hw_config(sdata->local,
+                                    IEEE80211_CONF_CHANGE_CHANNEL);
+                ieee80211_offchannel_return(sdata->local, true);
+        }
+
+        ieee80211_recalc_idle(local);
+
+        return 0;
+}