src: add expression handler hashtable

netlink_parsers is actually small, but update this code to use a
hashtable instead since more expressions may come in the future.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/cache.h b/include/cache.h
index 213a6eaf..b9db1a8f 100644
--- a/include/cache.h
+++ b/include/cache.h
@@ -35,4 +35,14 @@ enum cache_level_flags {
 	NFT_CACHE_FLUSHED	= (1 << 31),
 };
 
+static inline uint32_t djb_hash(const char *key)
+{
+	uint32_t i, hash = 5381;
+
+	for (i = 0; i < strlen(key); i++)
+		hash = ((hash << 5) + hash) + key[i];
+
+	return hash;
+}
+
 #endif /* _NFT_CACHE_H_ */