ipv4: Notify route if replacing currently offloaded one

When replacing a route, its replacement should only be notified in case
the replaced route is of any interest to listeners. In other words, if
the replaced route is currently used in the data path, which means it is
the first route in the FIB alias list with the given {prefix, prefix
length, table ID}.

v2:
* Convert to use fib_find_alias() instead of fib_find_first_alias()

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-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 4c22e768a5b53ccd2589a3cdd6303cb44b784d71..4c80ac0344f48aebcf4de3dc71d968fb9f0367db 100644 (file)
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -1222,6 +1222,17 @@ int fib_table_insert(struct net *net, struct fib_table *tb,
                        new_fa->tb_id = tb->tb_id;
                        new_fa->fa_default = -1;
 
+                       if (fib_find_alias(&l->leaf, fa->fa_slen, 0, 0,
+                                          tb->tb_id, true) == fa) {
+                               enum fib_event_type fib_event;
+
+                               fib_event = FIB_EVENT_ENTRY_REPLACE_TMP;
+                               err = call_fib_entry_notifiers(net, fib_event,
+                                                              key, plen,
+                                                              new_fa, extack);
+                               if (err)
+                                       goto out_free_new_fa;
+                       }
                        err = call_fib_entry_notifiers(net,
                                                       FIB_EVENT_ENTRY_REPLACE,
                                                       key, plen, new_fa,