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>

1 files changed, 72 insertions, 54 deletions

diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index 9c836e774fbd..c3a0b0a4f97f 100644
--- 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: