[nft PATCH v4 5/7] rule: Introduce rule_lookup_by_index()

[Phil Sutter <phil@nwl.cc>]

In contrast to rule_lookup(), this function returns a chain's rule at a
given index instead of by handle.

Signed-off-by: Phil Sutter <phil@nwl.cc>
---
 include/rule.h |  2 ++
 src/rule.c     | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/include/rule.h b/include/rule.h
index 61aa040a2e891..a7dd042d60e3f 100644
--- a/include/rule.h
+++ b/include/rule.h
@@ -260,6 +260,8 @@ extern struct rule *rule_get(struct rule *rule);
 extern void rule_free(struct rule *rule);
 extern void rule_print(const struct rule *rule, struct output_ctx *octx);
 extern struct rule *rule_lookup(const struct chain *chain, uint64_t handle);
+extern struct rule *rule_lookup_by_index(const struct chain *chain,
+					 uint64_t index);
 
 /**
  * struct set - nftables set
diff --git a/src/rule.c b/src/rule.c
index 78e0388e41e93..dc2dd3628b17f 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -716,6 +716,17 @@ struct rule *rule_lookup(const struct chain *chain, uint64_t handle)
 	return NULL;
 }
 
+struct rule *rule_lookup_by_index(const struct chain *chain, uint64_t index)
+{
+	struct rule *rule;
+
+	list_for_each_entry(rule, &chain->rules, list) {
+		if (!--index)
+			return rule;
+	}
+	return NULL;
+}
+
 struct scope *scope_init(struct scope *scope, const struct scope *parent)
 {
 	scope->parent = parent;
-- 
2.21.0