GAP: allow to limit number of connections in LE Peripheral role with gap_set_max_number_peripheral_connections

CHANGELOG.md

@@ -6,6 +6,15 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+### Changed
+- GAP: allow to limit number of connections in LE Peripheral role with gap_set_max_number_peripheral_connections
+
+### Fixed
+
+## Changes February 2018
+
 ### Added
 - Port for Windows with Zephyr HCI Firmware connected via serial port  
 - em9304: ability to upload patch containers during HCI bootup.

src/gap.h

@@ -339,6 +339,13 @@ void gap_get_connection_parameter_range(le_connection_parameter_range_t * range)
  */
 void gap_set_connection_parameter_range(le_connection_parameter_range_t * range);
 
+/**
+ * @brief Set max number of connections in LE Peripheral role (if Bluetooth Controller supports it)
+ * @note: default: 1
+ * @param max_peripheral_connections
+ */
+void gap_set_max_number_peripheral_connections(int max_peripheral_connections);
+
 /**
  * @brief Connect to remote LE device
  */

src/hci.c

@@ -225,6 +225,15 @@ void gap_set_connection_parameter_range(le_connection_parameter_range_t *range){
     hci_stack->le_connection_parameter_range = *range;
 }
 
+/**
+ * @brief Set max number of connections in LE Peripheral role (if Bluetooth Controller supports it)
+ * @note: default: 1
+ * @param max_peripheral_connections
+ */
+void gap_set_max_number_peripheral_connections(int max_peripheral_connections){
+    hci_stack->le_max_number_peripheral_connections = max_peripheral_connections;
+}
+
 /**
  * get hci connections iterator
  *
@@ -1021,6 +1030,31 @@ void le_handle_advertisement_report(uint8_t *packet, uint16_t size){
 #endif
 #endif
 
+#ifdef ENABLE_BLE
+#ifdef ENABLE_LE_PERIPHERAL
+static void hci_reenable_advertisements_if_needed(void){
+    if (!hci_stack->le_advertisements_active && hci_stack->le_advertisements_enabled){
+        // get number of active le slave connections
+        int num_slave_connections = 0;
+        btstack_linked_list_iterator_t it;
+        btstack_linked_list_iterator_init(&it, &hci_stack->connections);
+        while (btstack_linked_list_iterator_has_next(&it)){
+            hci_connection_t * con = (hci_connection_t*) btstack_linked_list_iterator_next(&it);
+            log_info("state %u, role %u, le_con %u", con->state, con->role, hci_is_le_connection(con));
+            if (con->state != OPEN) continue;
+            if (con->role  != HCI_ROLE_SLAVE) continue;
+            if (!hci_is_le_connection(con)) continue;
+            num_slave_connections++;
+        }
+        log_info("Num LE Peripheral roles: %u of %u", num_slave_connections, hci_stack->le_max_number_peripheral_connections);
+        if (num_slave_connections < hci_stack->le_max_number_peripheral_connections){
+            hci_stack->le_advertisements_todo |= LE_ADVERTISEMENT_TASKS_ENABLE;
+        }
+    }
+}
+#endif
+#endif
+
 #if !defined(HAVE_PLATFORM_IPHONE_OS) && !defined (HAVE_HOST_CONTROLLER_API)
 
 static uint32_t hci_transport_uart_get_main_baud_rate(void){
@@ -2145,8 +2179,8 @@ static void event_handler(uint8_t *packet, int size){
             if (!conn) break; 
 #ifdef ENABLE_BLE
 #ifdef ENABLE_LE_PERIPHERAL
-            if (hci_is_le_connection(conn) && hci_stack->le_advertisements_enabled){
-                hci_stack->le_advertisements_todo |= LE_ADVERTISEMENT_TASKS_ENABLE;
+            if (hci_is_le_connection(conn)){
+                hci_reenable_advertisements_if_needed();
             }
 #endif
 #endif
@@ -2259,8 +2293,6 @@ static void event_handler(uint8_t *packet, int size){
 #ifdef ENABLE_LE_PERIPHERAL
                         // if we're slave, it was an incoming connection, advertisements have stopped
                         hci_stack->le_advertisements_active = 0;
-                        // try to re-enable them
-                        hci_stack->le_advertisements_todo |= LE_ADVERTISEMENT_TASKS_ENABLE;
 #endif
                     }
                     // LE connections are auto-accepted, so just create a connection if there isn't one already
@@ -2276,6 +2308,12 @@ static void event_handler(uint8_t *packet, int size){
                     conn->role  = packet[6];
                     conn->con_handle = little_endian_read_16(packet, 4);
                     
+#ifdef ENABLE_LE_PERIPHERAL
+                    if (packet[6] == HCI_ROLE_SLAVE){
+                        hci_reenable_advertisements_if_needed();
+                    }
+#endif
+
                     // TODO: store - role, peer address type, conn_interval, conn_latency, supervision timeout, master clock
 
                     // restart timer
@@ -2511,6 +2549,10 @@ void hci_init(const hci_transport_t *transport, const void *config){
     hci_stack->le_maximum_ce_length       = 0x0030;    // 30 ms
 #endif
 
+#ifdef ENABLE_LE_PERIPHERAL
+    hci_stack->le_max_number_peripheral_connections = 1; // only single connection as peripheral
+#endif
+
     // connection parameter range used to answer connection parameter update requests in l2cap
     hci_stack->le_connection_parameter_range.le_conn_interval_min =          6; 
     hci_stack->le_connection_parameter_range.le_conn_interval_max =       3200;

src/hci.h

@@ -832,6 +832,8 @@ typedef struct {
     uint8_t  le_advertisements_channel_map;
     uint8_t  le_advertisements_filter_policy;
     bd_addr_t le_advertisements_direct_address;
+
+    uint8_t le_max_number_peripheral_connections;
 #endif
 
 #ifdef ENABLE_LE_DATA_LENGTH_EXTENSION