chain: Add lookup functions for chain list and rules in chain

For now, these lookup functions simply iterate over the linked list
until they find the right entry. In future, they may make use of more
optimized data structures behind the curtains.

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

2 files changed, 31 insertions, 0 deletions

diff --git a/src/chain.c b/src/chain.c
index c8b7f9b..8668fb7d 100644
--- a/src/chain.c
+++ b/src/chain.c
@@ -734,6 +734,20 @@ int nftnl_rule_foreach(struct nftnl_chain *c,
        return 0;
 }
 
+EXPORT_SYMBOL(nftnl_rule_lookup_byindex);
+struct nftnl_rule *
+nftnl_rule_lookup_byindex(struct nftnl_chain *c, uint32_t index)
+{
+	struct nftnl_rule *r;
+
+	list_for_each_entry(r, &c->rule_list, head) {
+		if (!index)
+			return r;
+		index--;
+	}
+	return NULL;
+}
+
 struct nftnl_rule_iter {
 	const struct nftnl_chain	*c;
 	struct nftnl_rule		*cur;
@@ -856,6 +870,20 @@ int nftnl_chain_list_foreach(struct nftnl_chain_list *chain_list,
 	return 0;
 }
 
+EXPORT_SYMBOL(nftnl_chain_list_lookup_byname);
+struct nftnl_chain *
+nftnl_chain_list_lookup_byname(struct nftnl_chain_list *chain_list,
+			       const char *chain)
+{
+	struct nftnl_chain *c;
+
+	list_for_each_entry(c, &chain_list->list, head) {
+		if (!strcmp(chain, c->name))
+			return c;
+	}
+	return NULL;
+}
+
 struct nftnl_chain_list_iter {
 	const struct nftnl_chain_list	*list;
 	struct nftnl_chain		*cur;
diff --git a/src/libnftnl.map b/src/libnftnl.map
index 96d5b5f..0d3be32 100644
--- a/src/libnftnl.map
+++ b/src/libnftnl.map
@@ -345,4 +345,7 @@ LIBNFTNL_12 {
   nftnl_rule_iter_create;
   nftnl_rule_iter_next;
   nftnl_rule_iter_destroy;
+
+  nftnl_chain_list_lookup_byname;
+  nftnl_rule_lookup_byindex;
 } LIBNFTNL_11;