mac80211: Implement HT mixed protection mode

Section 9.23.3.5 of IEEE 80211s standard describes the protection rules for
HT mesh STA in a MBSS. Three HT protection modes are supported for now:

non-HT mixed mode - is selected if any non-HT peers are present in our MBSS.
20MHz-protection mode - is selected if all peers in our 20/40MHz MBSS support
			HT and atleast one HT20 peer is present.
no-protection mode - is selected otherwise.

This is a limited implementation of 9.23.3.5, which only considers mesh peers
when determining the HT protection mode. Station's channel_type needs to be
maintained.

Signed-off-by: Ashok Nagarajan <ashok@cozybit.com>
Reviewed-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 6209327..2e0ae73 100644 (file)
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -105,6 +105,66 @@ static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata,
        return sta;
 }
 
+/** mesh_set_ht_prot_mode - set correct HT protection mode
+ *
+ * Section 9.23.3.5 of IEEE 80211s standard describes the protection rules for
+ * HT mesh STA in a MBSS. Three HT protection modes are supported for now,
+ * non-HT mixed mode, 20MHz-protection and no-protection mode. non-HT mixed
+ * mode is selected if any non-HT peers are present in our MBSS.
+ * 20MHz-protection mode is selected if all peers in our 20/40MHz MBSS support
+ * HT and atleast one HT20 peer is present. Otherwise no-protection mode is
+ * selected.
+ */
+static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata)
+{
+       struct ieee80211_local *local = sdata->local;
+       struct sta_info *sta;
+       u32 changed = 0;
+       u16 ht_opmode;
+       bool non_ht_sta = false, ht20_sta = false;
+
+       if (local->_oper_channel_type == NL80211_CHAN_NO_HT)
+               return 0;
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sta, &local->sta_list, list) {
+               if (sdata == sta->sdata &&
+                   sta->plink_state == NL80211_PLINK_ESTAB) {
+                       switch (sta->ch_type) {
+                       case NL80211_CHAN_NO_HT:
+                               mpl_dbg("mesh_plink %pM: nonHT sta (%pM) is present",
+                                       sdata->vif.addr, sta->sta.addr);
+                               non_ht_sta = true;
+                               goto out;
+                       case NL80211_CHAN_HT20:
+                               mpl_dbg("mesh_plink %pM: HT20 sta (%pM) is present",
+                                       sdata->vif.addr, sta->sta.addr);
+                               ht20_sta = true;
+                       default:
+                               break;
+                       }
+               }
+       }
+out:
+       rcu_read_unlock();
+
+       if (non_ht_sta)
+               ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONHT_MIXED;
+       else if (ht20_sta && local->_oper_channel_type > NL80211_CHAN_HT20)
+               ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_20MHZ;
+       else
+               ht_opmode = IEEE80211_HT_OP_MODE_PROTECTION_NONE;
+
+       if (sdata->vif.bss_conf.ht_operation_mode != ht_opmode) {
+               sdata->vif.bss_conf.ht_operation_mode = ht_opmode;
+               changed = BSS_CHANGED_HT;
+               mpl_dbg("mesh_plink %pM: protection mode changed to %d",
+                       sdata->vif.addr, ht_opmode);
+       }
+
+       return changed;
+}
+
 /**
  * __mesh_plink_deactivate - deactivate mesh peer link
  *
@@ -302,11 +362,14 @@ static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata,
        else
                memset(&sta->sta.ht_cap, 0, sizeof(sta->sta.ht_cap));
 
-       if (elems->ht_operation)
+       if (elems->ht_operation) {
                if (!(elems->ht_operation->ht_param &
                      IEEE80211_HT_PARAM_CHAN_WIDTH_ANY))
                        sta->sta.ht_cap.cap &=
                                            ~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
+               sta->ch_type =
+                       ieee80211_ht_oper_to_channel_type(elems->ht_operation);
+       }
 
        rate_control_rate_init(sta);
        spin_unlock_bh(&sta->lock);
@@ -495,9 +558,10 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
        enum plink_event event;
        enum ieee80211_self_protected_actioncode ftype;
        size_t baselen;
-       bool deactivated, matches_local = true;
+       bool matches_local = true;
        u8 ie_len;
        u8 *baseaddr;
+       u32 changed = 0;
        __le16 plid, llid, reason;
 #ifdef CONFIG_MAC80211_VERBOSE_MPL_DEBUG
        static const char *mplstates[] = {
@@ -783,7 +847,8 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                        sta->plink_state = NL80211_PLINK_ESTAB;
                        spin_unlock_bh(&sta->lock);
                        mesh_plink_inc_estab_count(sdata);
-                       ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+                       changed |= mesh_set_ht_prot_mode(sdata);
+                       changed |= BSS_CHANGED_BEACON;
                        mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
                                sta->sta.addr);
                        break;
@@ -818,7 +883,8 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                        sta->plink_state = NL80211_PLINK_ESTAB;
                        spin_unlock_bh(&sta->lock);
                        mesh_plink_inc_estab_count(sdata);
-                       ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+                       changed |= mesh_set_ht_prot_mode(sdata);
+                       changed |= BSS_CHANGED_BEACON;
                        mpl_dbg("Mesh plink with %pM ESTABLISHED\n",
                                sta->sta.addr);
                        mesh_plink_frame_tx(sdata,
@@ -836,13 +902,13 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
                case CLS_ACPT:
                        reason = cpu_to_le16(WLAN_REASON_MESH_CLOSE);
                        sta->reason = reason;
-                       deactivated = __mesh_plink_deactivate(sta);
+                       __mesh_plink_deactivate(sta);
                        sta->plink_state = NL80211_PLINK_HOLDING;
                        llid = sta->llid;
                        mod_plink_timer(sta, dot11MeshHoldingTimeout(sdata));
                        spin_unlock_bh(&sta->lock);
-                       if (deactivated)
-                               ieee80211_bss_info_change_notify(sdata, BSS_CHANGED_BEACON);
+                       changed |= mesh_set_ht_prot_mode(sdata);
+                       changed |= BSS_CHANGED_BEACON;
                        mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,
                                            sta->sta.addr, llid, plid, reason);
                        break;
@@ -889,4 +955,7 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m
        }
 
        rcu_read_unlock();
+
+       if (changed)
+               ieee80211_bss_info_change_notify(sdata, changed);
 }

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index f75f5d9..663dc90 100644 (file)
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -362,6 +362,7 @@ struct sta_info {
        struct timer_list plink_timer;
        s64 t_offset;
        s64 t_offset_setpoint;
+       enum nl80211_channel_type ch_type;
 #endif
 
 #ifdef CONFIG_MAC80211_DEBUGFS