mac80211: introduce TDLS channel switch ops

Implement the cfg80211 TDLS channel switch ops and introduce new mac80211
ones for low-level drivers.
Verify low-level driver support for the new ops when using the relevant
wiphy feature bit. Also verify the peer supports channel switching before
passing the command down.

Add a new STA flag to track the off-channel state with the TDLS peer and
make sure to cancel the channel-switch if the peer STA is unexpectedly
removed.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

9 files changed, 362 insertions, 5 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8195e65d8a91..e75d5c53e97b 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -3752,6 +3752,8 @@ const struct cfg80211_ops mac80211_config_ops = {
         .set_rekey_data = ieee80211_set_rekey_data,
         .tdls_oper = ieee80211_tdls_oper,
         .tdls_mgmt = ieee80211_tdls_mgmt,
+        .tdls_channel_switch = ieee80211_tdls_channel_switch,
+        .tdls_cancel_channel_switch = ieee80211_tdls_cancel_channel_switch,
         .probe_client = ieee80211_probe_client,
         .set_noack_map = ieee80211_set_noack_map,
 #ifdef CONFIG_PM
diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index 2ba7f53746da..94c70091bbd7 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -74,7 +74,7 @@ static ssize_t sta_flags_read(struct file *file, char __user *userbuf,
         test_sta_flag(sta, WLAN_STA_##flg) ? #flg "\n" : ""
 
         int res = scnprintf(buf, sizeof(buf),
-                            "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
+                            "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s",
                             TEST(AUTH), TEST(ASSOC), TEST(PS_STA),
                             TEST(PS_DRIVER), TEST(AUTHORIZED),
                             TEST(SHORT_PREAMBLE),
@@ -83,10 +83,10 @@ static ssize_t sta_flags_read(struct file *file, char __user *userbuf,
                             TEST(MFP), TEST(BLOCK_BA), TEST(PSPOLL),
                             TEST(UAPSD), TEST(SP), TEST(TDLS_PEER),
                             TEST(TDLS_PEER_AUTH), TEST(TDLS_INITIATOR),
-                            TEST(TDLS_CHAN_SWITCH), TEST(4ADDR_EVENT),
-                            TEST(INSERTED), TEST(RATE_CONTROL),
-                            TEST(TOFFSET_KNOWN), TEST(MPSP_OWNER),
-                            TEST(MPSP_RECIPIENT));
+                            TEST(TDLS_CHAN_SWITCH), TEST(TDLS_OFF_CHANNEL),
+                            TEST(4ADDR_EVENT), TEST(INSERTED),
+                            TEST(RATE_CONTROL), TEST(TOFFSET_KNOWN),
+                            TEST(MPSP_OWNER), TEST(MPSP_RECIPIENT));
 #undef TEST
         return simple_read_from_buffer(userbuf, count, ppos, buf, res);
 }
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 9759dd1f0734..ec4ae42ac15f 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -1296,4 +1296,45 @@ static inline int drv_get_txpower(struct ieee80211_local *local,
         return ret;
 }
 
+static inline int
+drv_tdls_channel_switch(struct ieee80211_local *local,
+                        struct ieee80211_sub_if_data *sdata,
+                        struct ieee80211_sta *sta, u8 oper_class,
+                        struct cfg80211_chan_def *chandef,
+                        struct sk_buff *tmpl_skb, u32 ch_sw_tm_ie)
+{
+        int ret;
+
+        might_sleep();
+        if (!check_sdata_in_driver(sdata))
+                return -EIO;
+
+        if (!local->ops->tdls_channel_switch)
+                return -EOPNOTSUPP;
+
+        trace_drv_tdls_channel_switch(local, sdata, sta, oper_class, chandef);
+        ret = local->ops->tdls_channel_switch(&local->hw, &sdata->vif, sta,
+                                              oper_class, chandef, tmpl_skb,
+                                              ch_sw_tm_ie);
+        trace_drv_return_int(local, ret);
+        return ret;
+}
+
+static inline void
+drv_tdls_cancel_channel_switch(struct ieee80211_local *local,
+                               struct ieee80211_sub_if_data *sdata,
+                               struct ieee80211_sta *sta)
+{
+        might_sleep();
+        if (!check_sdata_in_driver(sdata))
+                return;
+
+        if (!local->ops->tdls_cancel_channel_switch)
+                return;
+
+        trace_drv_tdls_cancel_channel_switch(local, sdata, sta);
+        local->ops->tdls_cancel_channel_switch(&local->hw, &sdata->vif, sta);
+        trace_drv_return_void(local);
+}
+
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e786ab6bc72c..2c7abc077b6b 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -2007,6 +2007,12 @@ int ieee80211_tdls_mgmt(struct wiphy *wiphy, struct net_device *dev,
 int ieee80211_tdls_oper(struct wiphy *wiphy, struct net_device *dev,
                         const u8 *peer, enum nl80211_tdls_operation oper);
 void ieee80211_tdls_peer_del_work(struct work_struct *wk);
+int ieee80211_tdls_channel_switch(struct wiphy *wiphy, struct net_device *dev,
+                                  const u8 *addr, u8 oper_class,
+                                  struct cfg80211_chan_def *chandef);
+void ieee80211_tdls_cancel_channel_switch(struct wiphy *wiphy,
+                                          struct net_device *dev,
+                                          const u8 *addr);
 
 extern const struct ethtool_ops ieee80211_ethtool_ops;
 
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 282a4f36eb92..774ccb2d9a76 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -764,6 +764,11 @@ int ieee80211_register_hw(struct ieee80211_hw *hw)
              local->hw.offchannel_tx_hw_queue >= local->hw.queues))
                 return -EINVAL;
 
+        if ((hw->wiphy->features & NL80211_FEATURE_TDLS_CHANNEL_SWITCH) &&
+            (!local->ops->tdls_channel_switch ||
+             !local->ops->tdls_cancel_channel_switch))
+                return -EOPNOTSUPP;
+
 #ifdef CONFIG_PM
         if (hw->wiphy->wowlan && (!local->ops->suspend || !local->ops->resume))
                 return -EINVAL;
diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c
index 97372514f287..86ca62765699 100644
--- a/net/mac80211/sta_info.c
+++ b/net/mac80211/sta_info.c
@@ -847,6 +847,15 @@ static int __must_check __sta_info_destroy_part1(struct sta_info *sta)
         if (WARN_ON(ret))
                 return ret;
 
+        /*
+         * for TDLS peers, make sure to return to the base channel before
+         * removal.
+         */
+        if (test_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL)) {
+                drv_tdls_cancel_channel_switch(local, sdata, &sta->sta);
+                clear_sta_flag(sta, WLAN_STA_TDLS_OFF_CHANNEL);
+        }
+
         list_del_rcu(&sta->list);
 
         drv_sta_pre_rcu_remove(local, sta->sdata, sta);
diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index b6702c810ad3..00f56eb72c60 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -50,6 +50,8 @@
  * @WLAN_STA_TDLS_INITIATOR: We are the initiator of the TDLS link with this
  *      station.
  * @WLAN_STA_TDLS_CHAN_SWITCH: This TDLS peer supports TDLS channel-switching
+ * @WLAN_STA_TDLS_OFF_CHANNEL: The local STA is currently off-channel with this
+ *      TDLS peer
  * @WLAN_STA_UAPSD: Station requested unscheduled SP while driver was
  *      keeping station in power-save mode, reply when the driver
  *      unblocks the station.
@@ -80,6 +82,7 @@ enum ieee80211_sta_info_flags {
         WLAN_STA_TDLS_PEER_AUTH,
         WLAN_STA_TDLS_INITIATOR,
         WLAN_STA_TDLS_CHAN_SWITCH,
+        WLAN_STA_TDLS_OFF_CHANNEL,
         WLAN_STA_UAPSD,
         WLAN_STA_SP,
         WLAN_STA_4ADDR_EVENT,
diff --git a/net/mac80211/tdls.c b/net/mac80211/tdls.c
index fa141aecd986..358f9a4512ad 100644
--- a/net/mac80211/tdls.c
+++ b/net/mac80211/tdls.c
@@ -449,6 +449,48 @@ ieee80211_tdls_add_setup_cfm_ies(struct ieee80211_sub_if_data *sdata,
         ieee80211_tdls_add_link_ie(sdata, skb, peer, initiator);
 }
 
+static void
+ieee80211_tdls_add_chan_switch_req_ies(struct ieee80211_sub_if_data *sdata,
+                                       struct sk_buff *skb, const u8 *peer,
+                                       bool initiator, const u8 *extra_ies,
+                                       size_t extra_ies_len, u8 oper_class,
+                                       struct cfg80211_chan_def *chandef)
+{
+        struct ieee80211_tdls_data *tf;