Better support for deleting entries in NetmaskTree and NetmaskGroup

- NetmaskTree erase() method now has optional cleanup parameter
  - cleanup_tree() method will remove "hanging" branches of the tree
- NetmaskGroup now has deleteMask() methods that use NetmaskTree:erase()

common/iputils.hh

@@ -722,13 +722,31 @@ public:
     return ret;
   }
 
-  //<! Removes key from TreeMap. This does not clean up the tree.
-  void erase(const key_type& key) {
+  void cleanup_tree(TreeNode* node)
+  {
+    // only cleaup this node if it has no children and node4 and node6 are both empty
+    if (!(node->left || node->right || node->node6 || node->node4)) {
+      // get parent node ptr
+      TreeNode* parent = node->parent;
+      // delete this node
+      if (parent) {
+	if (parent->left.get() == node)
+	  parent->left.reset();
+	else
+	  parent->right.reset();
+	// now recurse up to the parent
+	cleanup_tree(parent);
+      }
+    }
+  }
+
+  //<! Removes key from TreeMap. This optionally cleans up the tree.
+  void erase(const key_type& key, bool cleanup=false) {
     TreeNode *node = root.get();
 
     // no tree, no value
     if ( node == nullptr ) return;
-
+    
     // exact same thing as above, except
     if (key.getNetwork().sin4.sin_family == AF_INET) {
       std::bitset<32> addr(be32toh(key.getNetwork().sin4.sin_addr.s_addr));
@@ -750,6 +768,7 @@ public:
 	    it++;
 	}
         node->node4.reset();
+	if (cleanup) cleanup_tree(node);
       }
     } else {
       uint64_t* addr = (uint64_t*)key.getNetwork().sin6.sin6_addr.s6_addr;
@@ -775,6 +794,7 @@ public:
 	    it++;
 	}
         node->node6.reset();
+	if (cleanup) cleanup_tree(node);
       }
     }
   }
@@ -839,6 +859,21 @@ public:
     return match(&ip);
   }
 
+  bool lookup(const ComboAddress* ip, Netmask* nmp) const
+  {
+    const auto &ret = tree.lookup(*ip);
+    if (ret) {
+      if (nmp) *nmp = ret->first;
+      return ret->second;
+    }
+    return false;
+  }
+
+  bool lookup(const ComboAddress& ip, Netmask* nmp) const
+  {
+    return lookup(&ip, nmp);
+  }
+
   //! Add this string to the list of possible matches
   void addMask(const std::string &ip, bool positive=true)
   {
@@ -855,6 +890,18 @@ public:
     tree.insert(nm).second=positive;
   }
 
+  //! Delete this Netmask from the list of possible matches
+  void deleteMask(const Netmask& nm)
+  {
+    tree.erase(nm, true);
+  }
+
+  void deleteMask(const std::string& ip)
+  {
+    if (!ip.empty())
+      deleteMask(Netmask(ip));
+  }
+
   void clear()
   {
     tree.clear();