nimble/netif: notify on BLE connection events

pkg/nimble/netif/nimble_netif.c

@@ -27,6 +27,7 @@
 
 #include "net/ble.h"
 #include "net/bluetil/addr.h"
+#include "net/gnrc/netapi/notify.h"
 #include "net/gnrc/netif.h"
 #include "net/gnrc/netif/hdr.h"
 #include "net/gnrc/netreg.h"
@@ -39,6 +40,7 @@
 #include "host/ble_gap.h"
 #include "host/util/util.h"
 #include "mem/mem.h"
+#include <string.h>
 
 #define ENABLE_DEBUG            0
 #include "debug.h"
@@ -331,6 +333,29 @@ end:
     ble_l2cap_recv_ready(event->receive.chan, rxb);
 }
 
+/**
+ * @brief   Sends a netapi notification for a connection event.
+ *
+ * @param[in] notify    The type of notification event.
+ * @param[in] addr      BLE address of the node that (dis-)connected.
+ */
+static inline void _dispatch_connection_event(netapi_notify_t notify, const void *addr)
+{
+    if (!IS_USED(MODULE_GNRC_NETAPI_NOTIFY)) {
+        return;
+    }
+
+    netapi_notify_l2_connection_t event = {
+        .l2addr_len = BLE_ADDR_LEN,
+        .if_pid = _netif.pid,
+    };
+
+    memcpy(event.l2addr, addr, BLE_ADDR_LEN);
+
+    gnrc_netapi_notify(GNRC_NETTYPE_L2_DISCOVERY, GNRC_NETREG_DEMUX_CTX_ALL,
+                       notify, &event, sizeof(netapi_notify_l2_connection_t));
+}
+
 static int _on_l2cap_client_evt(struct ble_l2cap_event *event, void *arg)
 {
     int handle = (int)arg;
@@ -349,6 +374,7 @@ static int _on_l2cap_client_evt(struct ble_l2cap_event *event, void *arg)
             conn->state |= NIMBLE_NETIF_L2CAP_CLIENT;
             conn->state &= ~NIMBLE_NETIF_CONNECTING;
             _notify(handle, NIMBLE_NETIF_CONNECTED_MASTER, conn->addr);
+            _dispatch_connection_event(NETAPI_NOTIFY_L2_NEIGH_CONNECTED, conn->addr);
             break;
         case BLE_L2CAP_EVENT_COC_DISCONNECTED:
             assert(conn->state & NIMBLE_NETIF_L2CAP_CLIENT);
@@ -404,6 +430,7 @@ static int _on_l2cap_server_evt(struct ble_l2cap_event *event, void *arg)
             }
 
             _notify(handle, NIMBLE_NETIF_CONNECTED_SLAVE, conn->addr);
+            _dispatch_connection_event(NETAPI_NOTIFY_L2_NEIGH_CONNECTED, conn->addr);
             break;
         case BLE_L2CAP_EVENT_COC_DISCONNECTED:
             conn = nimble_netif_conn_from_gaphandle(event->disconnect.conn_handle);
@@ -498,6 +525,7 @@ static int _on_gap_master_evt(struct ble_gap_event *event, void *arg)
             nimble_netif_conn_free(handle, addr);
             thread_flags_set(_netif_thread, FLAG_TX_NOTCONN);
             _notify(handle, type, addr);
+            _dispatch_connection_event(NETAPI_NOTIFY_L2_NEIGH_DISCONNECTED, addr);
             break;
         }
         case BLE_GAP_EVENT_CONN_UPDATE:
@@ -542,6 +570,7 @@ static int _on_gap_slave_evt(struct ble_gap_event *event, void *arg)
             nimble_netif_conn_free(handle, addr);
             thread_flags_set(_netif_thread, FLAG_TX_NOTCONN);
             _notify(handle, type, addr);
+            _dispatch_connection_event(NETAPI_NOTIFY_L2_NEIGH_DISCONNECTED, addr);
             break;
         }
         case BLE_GAP_EVENT_CONN_UPDATE:

sys/include/net/gnrc/netapi/notify.h

@@ -46,7 +46,8 @@ extern "C" {
  *          be added for parsing the data and calling @ref gnrc_netapi_notify_ack.
  */
 typedef enum {
-    PLACEHOLDER
+    NETAPI_NOTIFY_L2_NEIGH_CONNECTED,       /**< Connection established on layer 2. */
+    NETAPI_NOTIFY_L2_NEIGH_DISCONNECTED,    /**< Connection closed on layer 2. */
 } netapi_notify_t;
 
 /**
@@ -59,6 +60,16 @@ typedef struct {
     sema_inv_t ack;                 /**< inverse semaphore for collecting ack's */
 } gnrc_netapi_notify_t;
 
+/**
+ * @brief   L2 connection event data associated with @ref NETAPI_NOTIFY_L2_NEIGH_CONNECTED or
+ *          @ref NETAPI_NOTIFY_L2_NEIGH_DISCONNECTED events.
+ */
+typedef struct {
+    uint8_t l2addr[GNRC_NETIF_L2ADDR_MAXLEN];   /**< L2 address of the node */
+    uint8_t l2addr_len;                         /**< length of L2 address in byte */
+    kernel_pid_t if_pid;                        /**< PID of network interface */
+} netapi_notify_l2_connection_t;
+
 /**
  * @brief   Acknowledge that a notify event was received and its data read.
  *

sys/include/net/gnrc/nettype.h

@@ -132,6 +132,13 @@ typedef enum {
      * }
      */
 
+    /**
+     * @brief   Reports the reachability of link-layer neighbors.
+     *          Connection-oriented links such as BLE can use this to inform
+     *          the IPv6-layer, e.g., about new connected or disconnected nodes
+     *          and their l2 address.
+     */
+    GNRC_NETTYPE_L2_DISCOVERY,
     /** @} */
 
     /**

sys/net/gnrc/netapi/notify/gnrc_netapi_notify.c

@@ -12,18 +12,43 @@
  * @author      Elena Frank <elena.frank@tu-dresden.de>
  */
 
+#include <assert.h>
 #include <errno.h>
 
 #include "net/gnrc/netapi/notify.h"
+#include "net/ipv6/addr.h"
+
+int _copy_l2_connection_data(gnrc_netapi_notify_t *notify, netapi_notify_l2_connection_t *data)
+{
+    assert(notify->_data_len == sizeof(netapi_notify_l2_connection_t));
+
+    /* Parse event data */
+    netapi_notify_l2_connection_t *recv_data = notify->_data;
+
+    if (recv_data->l2addr_len > GNRC_NETIF_L2ADDR_MAXLEN) {
+        return -EINVAL;
+    }
+    memcpy(data->l2addr, recv_data->l2addr, recv_data->l2addr_len);
+
+    data->l2addr_len = recv_data->l2addr_len;
+    data->if_pid = recv_data->if_pid;
+
+    return sizeof(netapi_notify_l2_connection_t);
+}
 
 int gnrc_netapi_notify_copy_event_data(gnrc_netapi_notify_t *notify, uint8_t data_len, void *data)
 {
-    (void) data_len;
-    (void) data;
-
     int res;
 
     switch (notify->event) {
+    case NETAPI_NOTIFY_L2_NEIGH_CONNECTED:
+    case NETAPI_NOTIFY_L2_NEIGH_DISCONNECTED:
+        if (data_len != sizeof(netapi_notify_l2_connection_t)) {
+            res = -EINVAL;
+            break;
+        }
+        res = _copy_l2_connection_data(notify, data);
+        break;
     default:
         res = -EINVAL;
         break;