BLE Host - disallow conn to already-connected peer

Now, ble_gap_connect() returns BLE_HS_EDONE if the specified peer is
already connected.

(BLE_HS_EALREADY is already being used here.  It gets returned if a
connect procedure is already in progress.)

X-Original-Commit: 4b17e1692358fa438b59aae6627cd7251658e029

nimble/host/src/ble_gap.c

@@ -2413,7 +2413,13 @@ ble_gap_conn_create_tx(uint8_t own_addr_type,
  * @param cb_arg                The optional argument to pass to the callback
  *                                  function.
  *
- * @return                      0 on success; nonzero on failure.
+ * @return                      0 on success;
+ *                              BLE_HS_EALREADY if a connection attempt is
+ *                                  already in progress;
+ *                              BLE_HS_EBUSY if initiating a connection is not
+ *                                  possible because scanning is in progress;
+ *                              BLE_HS_EDONE if the specified peer is already connected;
+ *                              Other nonzero on error.
  */
 int
 ble_gap_connect(uint8_t own_addr_type,
@@ -2475,6 +2481,12 @@ ble_gap_connect(uint8_t own_addr_type,
         }
     }
 
+    /* Verify peer not already connected. */
+    if (ble_hs_conn_find_by_addr(peer_addr_type, peer_addr) != NULL) {
+        rc = BLE_HS_EDONE;
+        goto done;
+    }
+
     /* XXX: Verify conn_params. */
 
     rc = ble_hs_id_use_addr(own_addr_type);

nimble/host/src/ble_hs_conn.c

@@ -258,7 +258,7 @@ ble_hs_conn_find_assert(uint16_t conn_handle)
 }
 
 struct ble_hs_conn *
-ble_hs_conn_find_by_addr(uint8_t addr_type, uint8_t *addr)
+ble_hs_conn_find_by_addr(uint8_t addr_type, const uint8_t *addr)
 {
 #if !NIMBLE_BLE_CONNECT
     return NULL;

nimble/host/src/ble_hs_conn_priv.h

@@ -85,7 +85,8 @@ void ble_hs_conn_insert(struct ble_hs_conn *conn);
 void ble_hs_conn_remove(struct ble_hs_conn *conn);
 struct ble_hs_conn *ble_hs_conn_find(uint16_t conn_handle);
 struct ble_hs_conn *ble_hs_conn_find_assert(uint16_t conn_handle);
-struct ble_hs_conn *ble_hs_conn_find_by_addr(uint8_t addr_type, uint8_t *addr);
+struct ble_hs_conn *ble_hs_conn_find_by_addr(uint8_t addr_type,
+                                             const uint8_t *addr);
 struct ble_hs_conn *ble_hs_conn_find_by_idx(int idx);
 int ble_hs_conn_exists(uint16_t conn_handle);
 struct ble_hs_conn *ble_hs_conn_first(void);

nimble/host/test/src/ble_gap_test.c

@@ -920,6 +920,27 @@ TEST_CASE(ble_gap_test_case_conn_gen_already)
     TEST_ASSERT(rc == BLE_HS_EALREADY);
 }
 
+TEST_CASE(ble_gap_test_case_conn_gen_done)
+{
+    static const struct ble_gap_conn_params conn_params = { 0 };
+    static const uint8_t peer_addr[6] = { 1, 2, 3, 4, 5, 6 };
+    int rc;
+
+    ble_gap_test_util_init();
+
+    /* Successfully connect to the peer. */
+    ble_hs_test_util_create_conn(2, peer_addr, ble_gap_test_util_connect_cb,
+                                 NULL);
+
+    /* Ensure host indicates BLE_HS_EDONE if we try to connect to the same
+     * peer.
+     */
+    rc = ble_gap_connect(BLE_ADDR_TYPE_PUBLIC, BLE_ADDR_TYPE_PUBLIC,
+                         peer_addr, BLE_HS_FOREVER, &conn_params,
+                         ble_gap_test_util_connect_cb, NULL);
+    TEST_ASSERT(rc == BLE_HS_EDONE);
+}
+
 TEST_CASE(ble_gap_test_case_conn_gen_busy)
 {
     static const struct ble_gap_disc_params disc_params = { 0 };
@@ -950,6 +971,7 @@ TEST_SUITE(ble_gap_test_suite_conn_gen)
     ble_gap_test_case_conn_gen_bad_args();
     ble_gap_test_case_conn_gen_dflt_params();
     ble_gap_test_case_conn_gen_already();
+    ble_gap_test_case_conn_gen_done();
     ble_gap_test_case_conn_gen_busy();
 }
 

nimble/host/test/src/ble_gatt_write_test.c

@@ -735,8 +735,6 @@ TEST_CASE(ble_gatt_write_test_reliable_oom)
     /* Initiate a write reliable procedure. */
     ble_hs_test_util_attr_from_flat(&mattr, &attr);
 
-    ble_hs_test_util_create_conn(2, ((uint8_t[]){2,3,4,5,6,7,8,9}),
-                                 NULL, NULL);
     off = 0;
     rc = ble_gattc_write_reliable(2, &mattr, 1,
                                   ble_gatt_write_test_reliable_cb_good, NULL);