From: Nick Porter <nick@portercomputing.co.uk>
Date: Thu, 11 Aug 2022 11:11:15 +0000 (+0100)
Subject: Add fr_pair_find_by_da_nested() to find pairs by their da structure
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e45713609eb248389ddb2e4b516e2d9897372b3d;p=thirdparty%2Ffreeradius-server.git

Add fr_pair_find_by_da_nested() to find pairs by their da structure
---

diff --git a/src/lib/util/pair.c b/src/lib/util/pair.c
index 09c45e8553f..51d69d764ca 100644
--- a/src/lib/util/pair.c
+++ b/src/lib/util/pair.c
@@ -696,6 +696,104 @@ fr_pair_t *fr_pair_find_by_da_idx(fr_pair_list_t const *list, fr_dict_attr_t con
 	return NULL;
 }
 
+/** Find a pair with a matching da walking the nested da tree
+ *
+ * The list should be the one containing the top level attributes.
+ *
+ * @param[in] list	to search in.
+ * @param[in] prev	pair to start searching from.
+ * @param[in] da	the next da to find.
+ * @return
+ *	- first matching fr_pair_t.
+ *	- NULL if no fr_pair_ts match.
+ */
+fr_pair_t *fr_pair_find_by_da_nested(fr_pair_list_t const *list, fr_pair_t const *prev, fr_dict_attr_t const *da)
+{
+	fr_pair_t		*vp;
+	fr_dict_attr_t const	**find;		/* DA currently being looked for */
+	fr_pair_list_t const	*cur_list;	/* Current list being searched */
+	fr_da_stack_t		da_stack;
+
+	if (fr_pair_list_empty(list)) return NULL;
+
+	/*
+	 *	In the common case, we're looking for attributes in
+	 *	the root (at level 1), so we just skip to a special
+	 *	function for that
+	 */
+	if (da->depth <= 1) return fr_pair_find_by_da(list, prev, da);
+
+	fr_proto_da_stack_build(&da_stack, da);
+
+	/*
+	 *	Find the relevant starting point for `prev`
+	 */
+	if (prev) {
+		cur_list = fr_pair_parent_list(prev);
+		find = &da_stack.da[prev->da->depth - 1];
+		vp = UNCONST(fr_pair_t *, prev);
+	} else {
+		cur_list = list;
+		find = &da_stack.da[0];
+		vp = NULL;
+	}
+
+	/*
+	 *	Loop over the list at each level until we find a matching da.
+	 */
+	while (true) {
+		fr_pair_t	*next;
+
+		fr_assert((*find)->depth <= da->depth);
+
+		/*
+		 *	Find a vp which matches a given da.  If found,
+		 *	recurse into the child list to find the child
+		 *	attribute.
+		 *
+		 */
+		next = fr_pair_find_by_da(cur_list, vp, *find);
+		if (next) {
+			/*
+			 *	We've found a match for the requested
+			 *	da - return it.
+			 */
+			if ((*find) == da) return next;
+
+			/*
+			 *	Prepare to search the next level.
+			 */
+			cur_list = &next->vp_group;
+			find++;
+			vp = NULL;
+			continue;
+		}
+
+		/*
+		 *	We hit the end of the top-level list.  Therefore we found nothing.
+		 */
+		if (cur_list == list) break;
+
+		/*
+		 *	We hit the end of *A* list.  Go to the parent
+		 *	VP, and then find its list.
+		 *
+		 *	We still then have to go to the next attribute
+		 *	in the parent list, as we've checked all of the
+		 *	children of this VP.
+		 */
+		find--;
+		vp = fr_pair_list_parent(cur_list);
+		cur_list = fr_pair_parent_list(vp);
+	}
+
+	/*
+	 *	Compatiblitity with flat atttrbutes
+	 */
+	if (fr_pair_parent_list(prev) != list) prev = NULL;
+	return fr_pair_find_by_da(list, prev, da);
+}
+
 /** Find a pair which has the specified ancestor
  *
  * @param[in] list	to search in.
diff --git a/src/lib/util/pair.h b/src/lib/util/pair.h
index ae295d4bd04..112099b4b52 100644
--- a/src/lib/util/pair.h
+++ b/src/lib/util/pair.h
@@ -408,6 +408,9 @@ fr_pair_t	*fr_pair_find_by_da(fr_pair_list_t const *list,
 fr_pair_t	*fr_pair_find_by_da_idx(fr_pair_list_t const *list,
 					fr_dict_attr_t const *da, unsigned int idx) CC_HINT(nonnull);
 
+fr_pair_t	*fr_pair_find_by_da_nested(fr_pair_list_t const *list, fr_pair_t const *prev,
+					   fr_dict_attr_t const *da) CC_HINT(nonnull(1,3));
+
 fr_pair_t	*fr_pair_find_by_ancestor(fr_pair_list_t const *list, fr_pair_t const *prev,
 					  fr_dict_attr_t const *ancestor) CC_HINT(nonnull(1,3));