[int][new][zbt] Add SMP callback

Project: Bluetooth

redmine: #5146, REDMINE-id

ext-redmine: bug|feat#id

When BLE paired, it will generate BT linkkey and give callback to upper layer. This callback
is used when Zephyr BT stack is not used with BLE. Callback will report BT link key for CTKD.

Affected branch: [master]

Change-Id: Ib867c59e0d9f3a2373a8ed935c80ca60226ee287

Author: Gang He

zephyr_bt/host/smp.c

@@ -821,11 +821,46 @@ static void smp_sign_info_sent(struct bt_conn *conn, void *user_data, int err)
 }
 #endif /* CONFIG_BT_SIGNING */
 
+
+/* Generate BR key from BLE key
+ * return 0: Success,  >0 has error, but continue, < 0 has error, abort.
+*/
+int ble_key_2_bt_key(bool use_h7, uint8_t *le_key, uint8_t *lebr_key)
+{
+    /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
+    static const uint8_t lebr[4] = { 0x72, 0x62, 0x65, 0x6c };
+    uint8_t ilk[16];
+    int r = 0;
+
+    if (use_h7)
+    {
+        /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
+        static const uint8_t salt[16] = { 0x31, 0x70, 0x6d, 0x74,
+                                          0x00, 0x00, 0x00, 0x00,
+                                          0x00, 0x00, 0x00, 0x00,
+                                          0x00, 0x00, 0x00, 0x00
+                                        };
+        r = bt_crypto_h7(salt, le_key, ilk);
+    }
+    else
+    {
+        /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
+        static const uint8_t tmp1[4] = { 0x31, 0x70, 0x6d, 0x74 };
+        r = bt_crypto_h6(le_key, tmp1, ilk);
+    }
+    if (r == 0)
+    {
+        r = bt_crypto_h6(ilk, lebr, lebr_key);
+        if (r < 0)
+            r = -r;
+    }
+    return r;
+}
+
 #if defined(CONFIG_BT_CLASSIC)
 static void sc_derive_link_key(struct bt_smp *smp)
 {
     /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
-    static const uint8_t lebr[4] = { 0x72, 0x62, 0x65, 0x6c };
     struct bt_conn *conn = smp->chan.chan.conn;
     struct bt_keys_link_key *link_key;
     uint8_t ilk[16];
@@ -844,36 +879,13 @@ static void sc_derive_link_key(struct bt_smp *smp)
         return;
     }
 
-    if (atomic_test_bit(smp->flags, SMP_FLAG_CT2))
-    {
-        /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
-        static const uint8_t salt[16] = { 0x31, 0x70, 0x6d, 0x74,
-                                          0x00, 0x00, 0x00, 0x00,
-                                          0x00, 0x00, 0x00, 0x00,
-                                          0x00, 0x00, 0x00, 0x00
-                                        };
-
-        if (bt_crypto_h7(salt, conn->le.keys->ltk.val, ilk))
-        {
-            bt_keys_link_key_clear(link_key);
-            return;
-        }
-    }
-    else
-    {
-        /* constants as specified in Core Spec Vol.3 Part H 2.4.2.4 */
-        static const uint8_t tmp1[4] = { 0x31, 0x70, 0x6d, 0x74 };
+    int r = ble_key_2_bt_key(atomic_test_bit(smp->flags, SMP_FLAG_CT2), conn->le.keys->ltk.val, link_key->val);
 
-        if (bt_crypto_h6(conn->le.keys->ltk.val, tmp1, ilk))
-        {
-            bt_keys_link_key_clear(link_key);
-            return;
-        }
-    }
-
-    if (bt_crypto_h6(ilk, lebr, link_key->val))
+    if (r)
     {
         bt_keys_link_key_clear(link_key);
+        if (r < 0)
+            return;
     }
 
     link_key->flags |= BT_LINK_KEY_SC;
@@ -1940,6 +1952,15 @@ static void smp_pairing_complete(struct bt_smp *smp, uint8_t status)
         {
             sc_derive_link_key(smp);
         }
+#else
+        uint8_t lebr_key[16];
+        const struct bt_conn_auth_cb *smp_auth_cb = latch_auth_cb(smp);
+
+        if (ble_key_2_bt_key(atomic_test_bit(smp->flags, SMP_FLAG_CT2), conn->le.keys->ltk.val, lebr_key) == 0)
+        {
+            if (smp_auth_cb->le_br_key)
+                smp_auth_cb->le_br_key(conn, lebr_key);
+        }
 #endif /* CONFIG_BT_CLASSIC */
         bool bond_flag = atomic_test_bit(smp->flags, SMP_FLAG_BOND);
         struct bt_conn_auth_info_cb *listener, *next;

zephyr_bt/include/zephyr/bluetooth/conn.h

@@ -2302,6 +2302,16 @@ struct bt_conn_auth_cb
      */
     void (*pairing_confirm)(struct bt_conn *conn);
 
+    /** @brief Request the user to enter a passkey.
+     *
+     *  This callback will be called for a BR/EDR (Bluetooth Classic)
+     *  key derived from BLE LTK.
+     *
+     *  @param conn Connection where pairing is currently active.
+     *  @param lebr_key BR key derived from LE connection LTK.
+     */
+    void (*le_br_key)(struct bt_conn *conn, uint8_t *lebr_key);
+
 #if defined(CONFIG_BT_CLASSIC)
     /** @brief Request the user to enter a passkey.
      *