mac80211: support extended channel switch

Support extended channel switch when the operating
class is one of the global operating classes as
defined in Annex E of 802.11-2012. If it isn't,
disconnect from the AP instead.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>

4 files changed, 71 insertions, 26 deletions

diff --git a/include/linux/ieee80211.h b/include/linux/ieee80211.h
index 8f80b3a93501..2a10acc65a54 100644
--- a/include/linux/ieee80211.h
+++ b/include/linux/ieee80211.h
@@ -673,6 +673,18 @@ struct ieee80211_channel_sw_ie {
 } __packed;
 
 /**
+ * struct ieee80211_ext_chansw_ie
+ *
+ * This structure represents the "Extended Channel Switch Announcement element"
+ */
+struct ieee80211_ext_chansw_ie {
+        u8 mode;
+        u8 new_operating_class;
+        u8 new_ch_num;
+        u8 count;
+} __packed;
+
+/**
  * struct ieee80211_tim
  *
  * This structure refers to "Traffic Indication Map information element"
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 373460f9c069..10c3180b165e 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -1178,6 +1178,7 @@ struct ieee802_11_elems {
         const u8 *perr;
         const struct ieee80211_rann_ie *rann;
         const struct ieee80211_channel_sw_ie *ch_switch_ie;
+        const struct ieee80211_ext_chansw_ie *ext_chansw_ie;
         const u8 *country_elem;
         const u8 *pwr_constr_elem;
         const struct ieee80211_timeout_interval_ie *timeout_int;
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index ade3cd6c337d..bc6f87edc624 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1024,56 +1024,79 @@ static void
 ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
                                  u64 timestamp, struct ieee802_11_elems *elems)
 {
+        struct ieee80211_local *local = sdata->local;
         struct ieee80211_if_managed *ifmgd = &sdata->u.mgd;
         struct cfg80211_bss *cbss = ifmgd->associated;
         struct ieee80211_bss *bss;
         struct ieee80211_channel *new_ch;
-        int new_freq;
         struct ieee80211_chanctx *chanctx;
+        enum ieee80211_band new_band;
+        int new_freq;
+        u8 new_chan_no;
+        u8 count;
+        u8 mode;
 
         ASSERT_MGD_MTX(ifmgd);
 
         if (!cbss)
                 return;
 
-        if (sdata->local->scanning)
+        if (local->scanning)
                 return;
 
         /* disregard subsequent announcements if we are already processing */
         if (ifmgd->flags & IEEE80211_STA_CSA_RECEIVED)
                 return;
 
-        if (!elems->ch_switch_ie)
+        if (elems->ext_chansw_ie) {
+                if (!ieee80211_operating_class_to_band(
+                                elems->ext_chansw_ie->new_operating_class,
+                                &new_band)) {
+                        sdata_info(sdata,
+                                   "cannot understand ECSA IE operating class %d, disconnecting\n",
+                                   elems->ext_chansw_ie->new_operating_class);
+                        ieee80211_queue_work(&local->hw,
+                                             &ifmgd->csa_connection_drop_work);
+                }
+                new_chan_no = elems->ext_chansw_ie->new_ch_num;
+                count = elems->ext_chansw_ie->count;
+                mode = elems->ext_chansw_ie->mode;
+        } else if (elems->ch_switch_ie) {
+                new_band = cbss->channel->band;
+                new_chan_no = elems->ch_switch_ie->new_ch_num;
+                count = elems->ch_switch_ie->count;
+                mode = elems->ch_switch_ie->mode;
+        } else {
+                /* nothing here we understand */
                 return;
+        }
 
         bss = (void *)cbss->priv;
 
-        new_freq = ieee80211_channel_to_frequency(
-                        elems->ch_switch_ie->new_ch_num,
-                        cbss->channel->band);
-        new_ch = ieee80211_get_channel(sdata->local->hw.wiphy, new_freq);
+        new_freq = ieee80211_channel_to_frequency(new_chan_no, new_band);
+        new_ch = ieee80211_get_channel(local->hw.wiphy, new_freq);
         if (!new_ch || new_ch->flags & IEEE80211_CHAN_DISABLED) {
                 sdata_info(sdata,
                            "AP %pM switches to unsupported channel (%d MHz), disconnecting\n",
                            ifmgd->associated->bssid, new_freq);
-                ieee80211_queue_work(&sdata->local->hw,
+                ieee80211_queue_work(&local->hw,
                                      &ifmgd->csa_connection_drop_work);
                 return;
         }
 
         ifmgd->flags |= IEEE80211_STA_CSA_RECEIVED;
 
-        if (sdata->local->use_chanctx) {
+        if (local->use_chanctx) {
                 sdata_info(sdata,
                            "not handling channel switch with channel contexts\n");
-                ieee80211_queue_work(&sdata->local->hw,
+                ieee80211_queue_work(&local->hw,
                                      &ifmgd->csa_connection_drop_work);
                 return;
         }
 
-        mutex_lock(&sdata->local->chanctx_mtx);
+        mutex_lock(&local->chanctx_mtx);
         if (WARN_ON(!rcu_access_pointer(sdata->vif.chanctx_conf))) {
-                mutex_unlock(&sdata->local->chanctx_mtx);
+                mutex_unlock(&local->chanctx_mtx);
                 return;
         }
         chanctx = container_of(rcu_access_pointer(sdata->vif.chanctx_conf),
@@ -1081,40 +1104,39 @@ ieee80211_sta_process_chanswitch(struct ieee80211_sub_if_data *sdata,
         if (chanctx->refcount > 1) {
                 sdata_info(sdata,
                            "channel switch with multiple interfaces on the same channel, disconnecting\n");
-                ieee80211_queue_work(&sdata->local->hw,
+                ieee80211_queue_work(&local->hw,
                                      &ifmgd->csa_connection_drop_work);
-                mutex_unlock(&sdata->local->chanctx_mtx);
+                mutex_unlock(&local->chanctx_mtx);
                 return;
         }
-        mutex_unlock(&sdata->local->chanctx_mtx);
+        mutex_unlock(&local->chanctx_mtx);
 
-        sdata->local->csa_channel = new_ch;
+        local->csa_channel = new_ch;
 
-        if (elems->ch_switch_ie->mode)
-                ieee80211_stop_queues_by_reason(&sdata->local->hw,
+        if (mode)
+                ieee80211_stop_queues_by_reason(&local->hw,
                                 IEEE80211_MAX_QUEUE_MAP,
                                 IEEE80211_QUEUE_STOP_REASON_CSA);
 
-        if (sdata->local->ops->channel_switch) {
+        if (local->ops->channel_switch) {
                 /* use driver's channel switch callback */
                 struct ieee80211_channel_switch ch_switch = {
                         .timestamp = timestamp,
-                        .block_tx = elems->ch_switch_ie->mode,
+                        .block_tx = mode,
                         .channel = new_ch,
-                        .count = elems->ch_switch_ie->count,
+                        .count = count,
                 };
 
-                drv_channel_switch(sdata->local, &ch_switch);
+                drv_channel_switch(local, &ch_switch);
                 return;
         }
 
         /* channel switch handled in software */
-        if (elems->ch_switch_ie->count <= 1)
-                ieee80211_queue_work(&sdata->local->hw, &ifmgd->chswitch_work);
+        if (count <= 1)
+                ieee80211_queue_work(&local->hw, &ifmgd->chswitch_work);
         else
                 mod_timer(&ifmgd->chswitch_timer,
-                          TU_TO_EXP_TIME(elems->ch_switch_ie->count *
-                                         cbss->beacon_interval));
+                          TU_TO_EXP_TIME(count * cbss->beacon_interval));
 }
 
 static u32 ieee80211_handle_pwr_constr(struct ieee80211_sub_if_data *sdata,
@@ -2629,6 +2651,8 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
         struct ieee80211_channel *channel;
         bool need_ps = false;
 
+        lockdep_assert_held(&sdata->u.mgd.mtx);
+
         if ((sdata->u.mgd.associated &&
              ether_addr_equal(mgmt->bssid, sdata->u.mgd.associated->bssid)) ||
             (sdata->u.mgd.assoc_data &&
@@ -2670,6 +2694,7 @@ static void ieee80211_rx_bss_info(struct ieee80211_sub_if_data *sdata,
         }
 
         ieee80211_sta_process_chanswitch(sdata, rx_status->mactime, elems);
+
 }
 
 
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 1d6217ac3ba3..e4a6d559372d 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -863,6 +863,13 @@ u32 ieee802_11_parse_elems_crc(u8 *start, size_t len,
                         }
                         elems->ch_switch_ie = (void *)pos;
                         break;
+                case WLAN_EID_EXT_CHANSWITCH_ANN:
+                        if (elen != sizeof(struct ieee80211_ext_chansw_ie)) {
+                                elem_parse_failed = true;
+                                break;
+                        }
+                        elems->ext_chansw_ie = (void *)pos;
+                        break;
                 case WLAN_EID_COUNTRY:
                         elems->country_elem = pos;
                         elems->country_elem_len = elen;