net: ipv4: Add extack message for invalid prefix or length

Add extack error message for invalid prefix length and invalid prefix.
Example of the latter is a route spec containing 172.16.100.1/24, where
the /24 mask means the lower 8-bits should be 0. Amazing how easy that
one is to overlook when an EINVAL is returned.

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

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index dcbfd5d..3dbfd5e 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -266,7 +266,8 @@ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
                     struct fib_result *res, int fib_flags);
 int fib_table_insert(struct net *, struct fib_table *, struct fib_config *,
                     struct netlink_ext_ack *extack);
-int fib_table_delete(struct net *, struct fib_table *, struct fib_config *);
+int fib_table_delete(struct net *, struct fib_table *, struct fib_config *,
+                    struct netlink_ext_ack *extack);
 int fib_table_dump(struct fib_table *table, struct sk_buff *skb,
                   struct netlink_callback *cb);
 int fib_table_flush(struct net *net, struct fib_table *table);

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 14d2f7b..715b796 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -588,7 +588,8 @@ int ip_rt_ioctl(struct net *net, unsigned int cmd, void __user *arg)
                        if (cmd == SIOCDELRT) {
                                tb = fib_get_table(net, cfg.fc_table);
                                if (tb)
-                                       err = fib_table_delete(net, tb, &cfg);
+                                       err = fib_table_delete(net, tb, &cfg,
+                                                              NULL);
                                else
                                        err = -ESRCH;
                        } else {
@@ -732,7 +733,7 @@ static int inet_rtm_delroute(struct sk_buff *skb, struct nlmsghdr *nlh,
                goto errout;
        }
 
-       err = fib_table_delete(net, tb, &cfg);
+       err = fib_table_delete(net, tb, &cfg, extack);
 errout:
        return err;
 }
@@ -851,7 +852,7 @@ static void fib_magic(int cmd, int type, __be32 dst, int dst_len, struct in_ifad
        if (cmd == RTM_NEWROUTE)
                fib_table_insert(net, tb, &cfg, NULL);
        else
-               fib_table_delete(net, tb, &cfg);
+               fib_table_delete(net, tb, &cfg, NULL);
 }
 
 void fib_add_ifaddr(struct in_ifaddr *ifa)

diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 9bd46e1..a624d38 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1099,13 +1099,18 @@ static int fib_insert_alias(struct trie *t, struct key_vector *tp,
        return 0;
 }
 
-static bool fib_valid_key_len(u32 key, u8 plen)
+static bool fib_valid_key_len(u32 key, u8 plen, struct netlink_ext_ack *extack)
 {
-       if (plen > KEYLENGTH)
+       if (plen > KEYLENGTH) {
+               NL_SET_ERR_MSG(extack, "Invalid prefix length");
                return false;
+       }
 
-       if ((plen < KEYLENGTH) && (key << plen))
+       if ((plen < KEYLENGTH) && (key << plen)) {
+               NL_SET_ERR_MSG(extack,
+                              "Invalid prefix for given prefix length");
                return false;
+       }
 
        return true;
 }
@@ -1128,7 +1133,7 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
 
        key = ntohl(cfg->fc_dst);
 
-       if (!fib_valid_key_len(key, plen))
+       if (!fib_valid_key_len(key, plen, extack))
                return -EINVAL;
 
        pr_debug("Insert table=%u %08x/%d\n", tb->tb_id, key, plen);
@@ -1516,7 +1521,7 @@ static void fib_remove_alias(struct trie *t, struct key_vector *tp,
 
 /* Caller must hold RTNL. */
 int fib_table_delete(struct net *net, struct fib_table *tb,
-                    struct fib_config *cfg)
+                    struct fib_config *cfg, struct netlink_ext_ack *extack)
 {
        struct trie *t = (struct trie *) tb->tb_data;
        struct fib_alias *fa, *fa_to_delete;
@@ -1528,7 +1533,7 @@ int fib_table_delete(struct net *net, struct fib_table *tb,
 
        key = ntohl(cfg->fc_dst);
 
-       if (!fib_valid_key_len(key, plen))
+       if (!fib_valid_key_len(key, plen, extack))
                return -EINVAL;
 
        l = fib_find_node(t, &tp, key);