From: Tsang-Shian Lin <thlin@xxxxxxxxxxx>
+bool rtl_check_beacon_key(struct ieee80211_hw *hw, void *data, unsigned int len)
+{
+ struct rtl_priv *rtlpriv = rtl_priv(hw);
+ struct rtl_mac *mac = rtl_mac(rtl_priv(hw));
+ struct rtl_phy *rtlphy = &rtlpriv->phy;
+ struct ieee80211_hdr *hdr = data;
+ struct ieee80211_ht_cap *ht_cap_ie;
+ struct ieee80211_ht_operation *ht_oper_ie = NULL;
+ struct rtl_beacon_keys bcn_key = {0};
+ struct rtl_beacon_keys *cur_bcn_key;
+ u8 *ht_cap;
+ u8 ht_cap_len;
+ u8 *ht_oper;
+ u8 ht_oper_len;
+ u8 *ds_param;
+ u8 ds_param_len;
+
+ if (mac->opmode != NL80211_IFTYPE_STATION)
+ return false;
+
+ /* check if this really is a beacon*/
+ if (!ieee80211_is_beacon(hdr->frame_control))
+ return false;
+
+ /* min. beacon length + FCS_LEN */
+ if (len <= 40 + FCS_LEN)
+ return false;
+
+ cur_bcn_key = &mac->cur_beacon_keys;
+
+ if (rtlpriv->mac80211.link_state == MAC80211_NOLINK) {
+ if (cur_bcn_key->valid) {
+ cur_bcn_key->valid = false;
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_LOUD,
+ "Reset cur_beacon_keys.valid to false!\n");
+ }
+ return false;
+ }
+
+ /* and only beacons from the associated BSSID, please */
+ if (!ether_addr_equal(hdr->addr3, rtlpriv->mac80211.bssid))
+ return false;
+
+ /***** Parsing DS Param IE ******/
+ ds_param = rtl_find_ie(data, len - FCS_LEN, WLAN_EID_DS_PARAMS);
+
+ if (ds_param && !(ds_param[1] < sizeof(*ds_param)))
+ ds_param_len = ds_param[1];
+ else
+ ds_param = NULL;
+
+ /***** Parsing HT Cap. IE ******/
+ ht_cap = rtl_find_ie(data, len - FCS_LEN, WLAN_EID_HT_CAPABILITY);
+
+ if (ht_cap && !(ht_cap[1] < sizeof(*ht_cap))) {
+ ht_cap_len = ht_cap[1];
+ ht_cap_ie = (struct ieee80211_ht_cap *)&ht_cap[2];
+ } else {
+ ht_cap = NULL;
+ ht_cap_ie = NULL;
+ }
+
+ /***** Parsing HT Info. IE ******/
+ ht_oper = rtl_find_ie(data, len - FCS_LEN, WLAN_EID_HT_OPERATION);
+
+ if (ht_oper && !(ht_oper[1] < sizeof(*ht_oper))) {
+ ht_oper_len = ht_oper[1];
+ ht_oper_ie = (struct ieee80211_ht_operation *)&ht_oper[2];
+ } else {
+ ht_oper = NULL;
+ }
+
+ /* update bcn_key */
+ memset(&bcn_key, 0, sizeof(bcn_key));
+
+ if (ds_param)
+ bcn_key.bcn_channel = ds_param[2];
+ else if (ht_oper && ht_oper_ie)
+ bcn_key.bcn_channel = ht_oper_ie->primary_chan;
+
+ if (ht_cap_ie)
+ bcn_key.ht_cap_info = ht_cap_ie->cap_info;
+
+ if (ht_oper && ht_oper_ie)
+ bcn_key.ht_info_infos_0_sco = ht_oper_ie->ht_param & 0x03;
+
+ bcn_key.valid = true;
+
+ /* update cur_beacon_keys or compare beacon key */
+ if (rtlpriv->mac80211.link_state != MAC80211_LINKED &&
+ rtlpriv->mac80211.link_state != MAC80211_LINKED_SCANNING)
+ return true;
+
+ if (!cur_bcn_key->valid) {
+ /* update cur_beacon_keys */
+ memset(cur_bcn_key, 0, sizeof(bcn_key));
+ memcpy(cur_bcn_key, &bcn_key, sizeof(bcn_key));
+ cur_bcn_key->valid = true;
+
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_LOUD,
+ "Beacon key update!ch=%d, ht_cap_info=0x%x, sco=0x%x\n",
+ cur_bcn_key->bcn_channel,
+ cur_bcn_key->ht_cap_info,
+ cur_bcn_key->ht_info_infos_0_sco);
+
+ return true;
+ }
+
+ /* compare beacon key */
+ if (!memcmp(cur_bcn_key, &bcn_key, sizeof(bcn_key))) {
+ /* same beacon key */
+ mac->new_beacon_cnt = 0;
+ goto chk_exit;
+ }
+
+ if (cur_bcn_key->bcn_channel == bcn_key.bcn_channel &&
+ cur_bcn_key->ht_cap_info == bcn_key.ht_cap_info) {
+ /* Beacon HT info IE, secondary channel offset check */
+ /* 40M -> 20M */
+ if (cur_bcn_key->ht_info_infos_0_sco >
+ bcn_key.ht_info_infos_0_sco) {
+ /* Not a new beacon */
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "Beacon BW change! sco:0x%x -> 0x%x\n",
+ cur_bcn_key->ht_info_infos_0_sco,
+ bcn_key.ht_info_infos_0_sco);
+
+ cur_bcn_key->ht_info_infos_0_sco =
+ bcn_key.ht_info_infos_0_sco;
+ } else {
+ /* 20M -> 40M */
+ if (rtlphy->max_ht_chan_bw >= HT_CHANNEL_WIDTH_20_40) {
+ /* Not a new beacon */
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "Beacon BW change! sco:0x%x -> 0x%x\n",
+ cur_bcn_key->ht_info_infos_0_sco,
+ bcn_key.ht_info_infos_0_sco);
+
+ cur_bcn_key->ht_info_infos_0_sco =
+ bcn_key.ht_info_infos_0_sco;
+ } else {
+ mac->new_beacon_cnt++;
+ }
+ }
+ } else {
+ mac->new_beacon_cnt++;
+ }
+
+ if (mac->new_beacon_cnt == 1) {
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "Get new beacon.\n");
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "Cur : ch=%d, ht_cap=0x%x, sco=0x%x\n",
+ cur_bcn_key->bcn_channel,
+ cur_bcn_key->ht_cap_info,
+ cur_bcn_key->ht_info_infos_0_sco);
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "New RX : ch=%d, ht_cap=0x%x, sco=0x%x\n",
+ bcn_key.bcn_channel,
+ bcn_key.ht_cap_info,
+ bcn_key.ht_info_infos_0_sco);
+
+ } else if (mac->new_beacon_cnt > 1) {
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "new beacon cnt: %d\n",
+ mac->new_beacon_cnt);
+ }
+
+ if (mac->new_beacon_cnt > 3) {
+ ieee80211_connection_loss(rtlpriv->mac80211.vif);
+ RT_TRACE(rtlpriv, COMP_BEACON, DBG_DMESG,
+ "new beacon cnt >3, disconnect !\n");
+ }
+
+chk_exit:
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(rtl_check_beacon_key);
