Add support to handle Data Length change event

nimble/host/include/host/ble_gap.h

@@ -142,6 +142,8 @@ struct hci_conn_update;
 #define BLE_GAP_EVENT_PERIODIC_TRANSFER     24
 #define BLE_GAP_EVENT_REATTEMPT_COUNT       25
 #define BLE_GAP_EVENT_VS_HCI                26
+#define BLE_GAP_EVENT_DATA_LEN_CHG          27
+
 
 /*** Reason codes for the subscribe GAP event. */
 
@@ -1001,6 +1003,29 @@ struct ble_gap_event {
         } reattempt_cnt;
 #endif
 
+        /**
+	 * Represent an event for LE Data length change
+	 *
+	 * Valid for the following event types:
+	 *      o BLE_GAP_EVENT_DATA_LEN_CHG
+	 */
+	struct {
+            /* Connection handle */
+	    uint16_t conn_handle;
+
+	    /* Max Tx Payload octotes */
+	    uint16_t max_tx_octets;
+
+	    /* Max Tx Time */
+	    uint16_t max_tx_time;
+
+	    /* Max Rx payload octet */
+	    uint16_t max_rx_octets;
+
+	    /* Max Rx Time */
+	    uint16_t max_rx_time;
+	} data_len_chg;
+
 #if MYNEWT_VAL(BLE_HCI_VS)
         /**
          * Represents a received vendor-specific HCI event

nimble/host/src/ble_gap.c

@@ -2039,6 +2039,25 @@ ble_gap_rx_phy_update_complete(const struct ble_hci_ev_le_subev_phy_update_compl
     ble_gap_call_conn_event_cb(&event, conn_handle);
 }
 
+void
+ble_gap_rx_data_len_change(const struct ble_hci_ev_le_subev_data_len_chg *ev)
+{
+#if NIMBLE_BLE_CONNECT
+    struct ble_gap_event event;
+    uint16_t conn_handle = le16toh(ev->conn_handle);
+
+    memset(&event, 0, sizeof event);
+    event.type = BLE_GAP_EVENT_DATA_LEN_CHG;
+    event.data_len_chg.max_tx_octets = le16toh(ev->max_tx_octets);
+    event.data_len_chg.max_rx_octets = le16toh(ev->max_rx_octets);
+    event.data_len_chg.max_tx_time = le16toh(ev->max_tx_time);
+    event.data_len_chg.max_rx_time = le16toh(ev->max_rx_time);
+
+    ble_gap_event_listener_call(&event);
+    ble_gap_call_conn_event_cb(&event, conn_handle);
+#endif
+}
+
 static int32_t
 ble_gap_master_timer(void)
 {

nimble/host/src/ble_gap_priv.h

@@ -152,6 +152,8 @@ int ble_gap_dbg_update_active(uint16_t conn_handle);
 void ble_gap_reattempt_count(uint16_t conn_handle, uint8_t count);
 #endif
 
+void ble_gap_rx_data_len_change(const struct ble_hci_ev_le_subev_data_len_chg *ev);
+
 #ifdef __cplusplus
 }
 #endif

nimble/host/src/ble_hs_hci_evt.c

@@ -65,6 +65,7 @@ static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_adv_rpt;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_conn_upd_complete;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_lt_key_req;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_conn_parm_req;
+static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_data_len_change;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_dir_adv_rpt;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_phy_update_complete;
 static ble_hs_hci_evt_le_fn ble_hs_hci_evt_le_ext_adv_rpt;
@@ -116,6 +117,7 @@ static ble_hs_hci_evt_le_fn * const ble_hs_hci_evt_le_dispatch[] = {
     [BLE_HCI_LE_SUBEV_CONN_UPD_COMPLETE] = ble_hs_hci_evt_le_conn_upd_complete,
     [BLE_HCI_LE_SUBEV_LT_KEY_REQ] = ble_hs_hci_evt_le_lt_key_req,
     [BLE_HCI_LE_SUBEV_REM_CONN_PARM_REQ] = ble_hs_hci_evt_le_conn_parm_req,
+    [BLE_HCI_LE_SUBEV_DATA_LEN_CHG] = ble_hs_hci_evt_le_data_len_change,
     [BLE_HCI_LE_SUBEV_ENH_CONN_COMPLETE] = ble_hs_hci_evt_le_enh_conn_complete,
     [BLE_HCI_LE_SUBEV_DIRECT_ADV_RPT] = ble_hs_hci_evt_le_dir_adv_rpt,
     [BLE_HCI_LE_SUBEV_PHY_UPDATE_COMPLETE] = ble_hs_hci_evt_le_phy_update_complete,
@@ -886,6 +888,22 @@ ble_hs_hci_evt_le_phy_update_complete(uint8_t subevent, const void *data,
     return 0;
 }
 
+static int
+ble_hs_hci_evt_le_data_len_change(uint8_t subevent, const void *data,
+				  unsigned int len)
+{
+    const struct ble_hci_ev_le_subev_data_len_chg *ev = data;
+
+    if (len != sizeof(*ev)) {
+        return BLE_HS_ECONTROLLER;
+    }
+
+    ble_gap_rx_data_len_change(ev);
+
+    return 0;
+
+}
+
 int
 ble_hs_hci_evt_process(const struct ble_hci_ev *ev)
 {