netfilter: nft_set_hash: fix get operation on big endian

tests/shell/testcases/packetpath/set_match_nomatch_hash_fast
fails on big endian with:

Error: Could not process rule: No such file or directory
reset element ip test s { 244.147.90.126 }
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Fatal: Cannot fetch element "244.147.90.126"

... because the wrong bucket is searched, jhash() and jhash1_word are
not interchangeable on big endian.

Fixes: 3b02b0a ("netfilter: nft_set_hash: fix lookups with fixed size hash on big endian")
Signed-off-by: Florian Westphal <fw@strlen.de>

Author: Florian Westphal

net/netfilter/nft_set_hash.c

@@ -619,15 +619,20 @@ static struct nft_elem_priv *
 nft_hash_get(const struct net *net, const struct nft_set *set,
 	     const struct nft_set_elem *elem, unsigned int flags)
 {
+	const u32 *key = (const u32 *)&elem->key.val;
 	struct nft_hash *priv = nft_set_priv(set);
 	u8 genmask = nft_genmask_cur(net);
 	struct nft_hash_elem *he;
 	u32 hash;
 
-	hash = jhash(elem->key.val.data, set->klen, priv->seed);
+	if (set->klen == 4)
+		hash = jhash_1word(*key, priv->seed);
+	else
+		hash = jhash(key, set->klen, priv->seed);
+
 	hash = reciprocal_scale(hash, priv->buckets);
 	hlist_for_each_entry_rcu(he, &priv->table[hash], node) {
-		if (!memcmp(nft_set_ext_key(&he->ext), elem->key.val.data, set->klen) &&
+		if (!memcmp(nft_set_ext_key(&he->ext), key, set->klen) &&
 		    nft_set_elem_active(&he->ext, genmask))
 			return &he->priv;
 	}