aioble/security: Add support for CCCD bonding.

Author: pi-anl

micropython/bluetooth/aioble/aioble/security.py

@@ -35,8 +35,8 @@
 limit_peers = None
 
 SEC_TYPES_SELF = (10, )
-SEC_TYPES_PEER = (1, 2, 3, 4)
-
+SEC_TYPES_PEER = (1, 2, 4)
+SEC_TYPES_CCCD = (3, )
 
 # Must call this before stack startup.
 def load_secrets(path=None):
@@ -105,14 +105,16 @@ def _save_secrets(arg=None):
         _modified = False
 
 
-def _remove_entry(sec_type, key):
+def _remove_entry(sec_type, key, value=None):
     secrets = _secrets[sec_type]
 
     # Delete existing secrets matching the type and key.
     deleted = False
     for to_delete in [
         entry for entry in secrets if entry[0] == key
     ]:
+        if value and to_delete[1] != value:
+            continue
         log_info("Removing existing secret matching key")
         secrets.remove(to_delete)
         deleted = True
@@ -124,7 +126,7 @@ def _log_peers(heading=""):
     if core.log_level <= 2:
         return
     log_info("secrets:", heading)
-    for sec_type in SEC_TYPES_PEER:
+    for sec_type in SEC_TYPES_PEER + SEC_TYPES_CCCD:
         log_info("-", sec_type)
 
         if sec_type not in _secrets:
@@ -171,8 +173,13 @@ def _security_irq(event, data):
             _secrets[sec_type] = []
         secrets = _secrets[sec_type]
 
-        # Delete existing secrets matching the type and key.
-        removed = _remove_entry(sec_type, key)
+        # Delete existing secrets matching the type and key as required.
+        # There should only every be one SEC_TYPES_PEER per addr, but 
+        # multiple entries are allowed for SEC_TYPES_CCCD
+        del_by_value = None
+        if not is_deleting and sec_type in SEC_TYPES_CCCD:
+            del_by_value = value
+        removed = _remove_entry(sec_type, key, del_by_value)
 
         if is_deleting and not removed:
             # Delete mode, but no entries were deleted
@@ -216,6 +223,9 @@ def _security_irq(event, data):
 
             for k, v in secrets:
                 if k == key:
+                    if index:
+                        index -= 1
+                        continue
                     return v
             return None