mac80211: refactor mesh peer initialization

This patch unifies the previous two paths toward mesh peer creation a
bit. It also fixes a bug where a peer's changing rates or HT mode
wouldn't register on leaving and then returning to the mesh with a sta
entry still present.

Also clean up locking and clear possibly stale ht cap.

Signed-off-by: Thomas Pedersen <thomas@cozybit.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 9c836e7..c3a0b0a 100644 (file)
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -82,20 +82,14 @@ static inline void mesh_plink_fsm_restart(struct sta_info *sta)
 }
 
 /*
- * NOTE: This is just an alias for sta_info_alloc(), see notes
- *       on it in the lifecycle management section!
+ * Allocate mesh sta entry and insert into station table
  */
 static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
-                                        u8 *hw_addr, u32 rates,
-                                        struct ieee802_11_elems *elems)
+                                        u8 *hw_addr)
 {
-       struct ieee80211_local *local = sdata->local;
-       struct ieee80211_supported_band *sband;
        struct sta_info *sta;
 
-       sband = local->hw.wiphy->bands[local->oper_channel->band];
-
-       if (local->num_sta >= MESH_MAX_PLINKS)
+       if (sdata->local->num_sta >= MESH_MAX_PLINKS)
                return NULL;
 
        sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL);
@@ -108,12 +102,8 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
 
        set_sta_flag(sta, WLAN_STA_WME);
 
-       sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
-       if (elems->ht_cap_elem)
-               ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
-                                                 elems->ht_cap_elem,
-                                                 &sta->sta.ht_cap);
-       rate_control_rate_init(sta);
+       if (sta_info_insert(sta))
+               return NULL;
 
        return sta;
 }
@@ -274,43 +264,76 @@ static int mesh_plink_frame_tx(struct ieee80211_sub_if_data *sdata,
        return 0;
 }
 
-void mesh_neighbour_update(u8 *hw_addr, u32 rates,
-               struct ieee80211_sub_if_data *sdata,
-               struct ieee802_11_elems *elems)
+/* mesh_peer_init - initialize new mesh peer and return resulting sta_info
+ *
+ * @sdata: local meshif
+ * @addr: peer's address
+ * @rates: station's supported rates
+ * @elems: IEs from beacon or mesh peering frame
+ *
+ * call under RCU
+ */
+static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
+                                      u8 *addr, u32 rates,
+                                      struct ieee802_11_elems *elems)
 {
        struct ieee80211_local *local = sdata->local;
+       struct ieee80211_supported_band *sband;
        struct sta_info *sta;
 
-       rcu_read_lock();
+       sband = local->hw.wiphy->bands[local->oper_channel->band];
 
-       sta = sta_info_get(sdata, hw_addr);
+       sta = sta_info_get(sdata, addr);
        if (!sta) {
-               rcu_read_unlock();
-               /* Userspace handles peer allocation when security is enabled
-                * */
-               if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED)
-                       cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
-                                       elems->ie_start, elems->total_len,
-                                       GFP_KERNEL);
-               else
-                       sta = mesh_plink_alloc(sdata, hw_addr, rates, elems);
+               sta = mesh_plink_alloc(sdata, addr);
                if (!sta)
-                       return;
-               if (sta_info_insert_rcu(sta)) {
-                       rcu_read_unlock();
-                       return;
-               }
+                       return NULL;
        }
 
+       spin_lock_bh(&sta->lock);
        sta->last_rx = jiffies;
        sta->sta.supp_rates[local->hw.conf.channel->band] = rates;
+       if (elems->ht_cap_elem)
+               ieee80211_ht_cap_ie_to_sta_ht_cap(sdata, sband,
+                                                 elems->ht_cap_elem,
+                                                 &sta->sta.ht_cap);
+       else
+               memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
+
+       rate_control_rate_init(sta);
+       spin_unlock_bh(&sta->lock);
+
+       return sta;
+}
+
+void mesh_neighbour_update(u8 *hw_addr, u32 rates,
+                          struct ieee80211_sub_if_data *sdata,
+                          struct ieee802_11_elems *elems)
+{
+       struct sta_info *sta;
+
+       /* Userspace handles peer allocation when security is enabled */
+       if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) {
+               cfg80211_notify_new_peer_candidate(sdata->dev, hw_addr,
+                                                  elems->ie_start,
+                                                  elems->total_len,
+                                                  GFP_KERNEL);
+               return;
+       }
+
+       rcu_read_lock();
+       sta = mesh_peer_init(sdata, hw_addr, rates, elems);
+       if (!sta)
+               goto out;
+
        if (mesh_peer_accepts_plinks(elems) &&
-                       sta->plink_state == NL80211_PLINK_LISTEN &&
-                       sdata->u.mesh.accepting_plinks &&
-                       sdata->u.mesh.mshcfg.auto_open_plinks &&
-                       rssi_threshold_check(sta, sdata))
+           sta->plink_state == NL80211_PLINK_LISTEN &&
+           sdata->u.mesh.accepting_plinks &&
+           sdata->u.mesh.mshcfg.auto_open_plinks &&
+           rssi_threshold_check(sta, sdata))
                mesh_plink_open(sta);
 
+out:
        rcu_read_unlock();
 }
 
@@ -587,26 +610,13 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                return;
        } else if (!sta) {
                /* ftype == WLAN_SP_MESH_PEERING_OPEN */
-
-               rcu_read_unlock();
-
                if (!mesh_plink_free_count(sdata)) {
                        mpl_dbg("Mesh plink error: no more free plinks\n");
-                       return;
-               }
-               sta = mesh_plink_alloc(sdata, mgmt->sa, rates, &elems);
-               if (!sta) {
-                       mpl_dbg("Mesh plink error: plink table full\n");
-                       return;
-               }
-               if (sta_info_insert_rcu(sta)) {
                        rcu_read_unlock();
                        return;
                }
                event = OPN_ACPT;
-               spin_lock_bh(&sta->lock);
        } else if (matches_local) {
-               spin_lock_bh(&sta->lock);
                switch (ftype) {
                case WLAN_SP_MESH_PEERING_OPEN:
                        if (!mesh_plink_free_count(sdata) ||
@@ -643,12 +653,19 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                        break;
                default:
                        mpl_dbg("Mesh plink: unknown frame subtype\n");
-                       spin_unlock_bh(&sta->lock);
                        rcu_read_unlock();
                        return;
                }
-       } else {
-               spin_lock_bh(&sta->lock);
+       }
+
+       if (event == OPN_ACPT) {
+               /* allocate sta entry if necessary and update info */
+               sta = mesh_peer_init(sdata, mgmt->sa, rates, &elems);
+               if (!sta) {
+                       mpl_dbg("Mesh plink: failed to init peer!\n");
+                       rcu_read_unlock();
+                       return;
+               }
        }
 
        mpl_dbg("Mesh plink (peer, state, llid, plid, event): %pM %s %d %d %d\n",
@@ -656,6 +673,7 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                le16_to_cpu(sta->llid), le16_to_cpu(sta->plid),
                event);
        reason = 0;
+       spin_lock_bh(&sta->lock);
        switch (sta->plink_state) {
                /* spin_unlock as soon as state is updated at each case */
        case NL80211_PLINK_LISTEN: