net: ipv4: refactor key and length checks

fib_table_insert and fib_table_delete have the same checks on the prefix
and length. Refactor into a helper. Avoids duplicate extack messages in
the next patch.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 6e9df7d..9bd46e1 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1099,6 +1099,17 @@ static int fib_insert_alias(struct trie *t, struct key_vector *tp,
        return 0;
 }
 
+static bool fib_valid_key_len(u32 key, u8 plen)
+{
+       if (plen > KEYLENGTH)
+               return false;
+
+       if ((plen < KEYLENGTH) && (key << plen))
+               return false;
+
+       return true;
+}
+
 /* Caller must hold RTNL. */
 int fib_table_insert(struct net *net, struct fib_table *tb,
                     struct fib_config *cfg, struct netlink_ext_ack *extack)
@@ -1115,16 +1126,13 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
        u32 key;
        int err;
 
-       if (plen > KEYLENGTH)
-               return -EINVAL;
-
        key = ntohl(cfg->fc_dst);
 
-       pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
-
-       if ((plen < KEYLENGTH) && (key << plen))
+       if (!fib_valid_key_len(key, plen))
                return -EINVAL;
 
+       pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
+
        fi = fib_create_info(cfg, extack);
        if (IS_ERR(fi)) {
                err = PTR_ERR(fi);
@@ -1518,12 +1526,9 @@ int fib_table_delete(struct net *net, struct fib_table *tb,
        u8 tos = cfg->fc_tos;
        u32 key;
 
-       if (plen > KEYLENGTH)
-               return -EINVAL;
-
        key = ntohl(cfg->fc_dst);
 
-       if ((plen < KEYLENGTH) && (key << plen))
+       if (!fib_valid_key_len(key, plen))
                return -EINVAL;
 
        l = fib_find_node(t, &tp, key);