Small changes to alias allocator:

- adds accessor to get the node id used for allocation.
- fixes todo to check whether newly generated aliases are in the existing caches.
- adds ability to get the next proposed alias from the sequence.

src/openlcb/AliasAllocator.cxx

@@ -111,9 +111,7 @@ StateFlowBase::Action AliasAllocator::entry()
     HASSERT(pending_alias()->state == AliasInfo::STATE_EMPTY);
     while (!pending_alias()->alias)
     {
-        pending_alias()->alias = seed_;
-        next_seed();
-        // TODO(balazs.racz): check if the alias is already known about.
+        pending_alias()->alias = get_new_seed();
     }
     // Registers ourselves as a handler for incoming CAN frames to detect
     // conflicts.
@@ -124,6 +122,24 @@ StateFlowBase::Action AliasAllocator::entry()
     return call_immediately(STATE(handle_allocate_for_cid_frame));
 }
 
+NodeAlias AliasAllocator::get_new_seed()
+{
+    while (true)
+    {
+        NodeAlias ret = seed_;
+        next_seed();
+        if (if_can()->local_aliases()->lookup(ret))
+        {
+            continue;
+        }
+        if (if_can()->remote_aliases()->lookup(ret))
+        {
+            continue;
+        }
+        return ret;
+    }
+}
+
 void AliasAllocator::next_seed()
 {
     uint16_t offset;

src/openlcb/AliasAllocator.hxx

@@ -108,13 +108,24 @@ public:
      */
     AliasAllocator(NodeID if_id, IfCan *if_can);
 
+    /** Destructor */
     virtual ~AliasAllocator();
 
+    /** @return the Node ID for the interface. */
+    NodeID if_id()
+    {
+        return if_id_;
+    }
+
     /** Resets the alias allocator to the state it was at construction. useful
      * after connection restart in order to ensure it will try to allocate the
      * same alias. */
     void reinit_seed();
 
+    /** Returns a new alias to check from the random sequence. Checks that it
+     * is not in the alias cache yet.*/
+    NodeAlias get_new_seed();
+
     /** "Allocate" a buffer from this pool (but without initialization) in
      * order to get a reserved alias. */
     QAsync *reserved_aliases()