ipv6: Notify newly added route if should be offloaded

fib6_add_rt2node() takes care of adding a single route ('struct
fib6_info') to a FIB node. The route in question should only be notified
in case it is added as the first route in the node (lowest metric) or if
it is added as a sibling route to the first route in the node.

The first criterion can be tested by checking if the route is pointed to
by 'fn->leaf'. The second criterion can be tested by checking the new
'notify_sibling_rt' variable that is set when the route is added as a
sibling to the first route in the node.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index 7bae6a9..045bcaf 100644 (file)
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1039,6 +1039,7 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt,
                   (info->nlh->nlmsg_flags & NLM_F_CREATE));
        int found = 0;
        bool rt_can_ecmp = rt6_qualify_for_ecmp(rt);
+       bool notify_sibling_rt = false;
        u16 nlflags = NLM_F_EXCL;
        int err;
 
@@ -1130,6 +1131,7 @@ next_iter:
 
                /* Find the first route that have the same metric */
                sibling = leaf;
+               notify_sibling_rt = true;
                while (sibling) {
                        if (sibling->fib6_metric == rt->fib6_metric &&
                            rt6_qualify_for_ecmp(sibling)) {
@@ -1139,6 +1141,7 @@ next_iter:
                        }
                        sibling = rcu_dereference_protected(sibling->fib6_next,
                                    lockdep_is_held(&rt->fib6_table->tb6_lock));
+                       notify_sibling_rt = false;
                }
                /* For each sibling in the list, increment the counter of
                 * siblings. BUG() if counters does not match, list of siblings
@@ -1166,6 +1169,21 @@ add:
                nlflags |= NLM_F_CREATE;
 
                if (!info->skip_notify_kernel) {
+                       enum fib_event_type fib_event;
+
+                       if (notify_sibling_rt)
+                               fib_event = FIB_EVENT_ENTRY_APPEND;
+                       else
+                               fib_event = FIB_EVENT_ENTRY_REPLACE_TMP;
+                       /* The route should only be notified if it is the first
+                        * route in the node or if it is added as a sibling
+                        * route to the first route in the node.
+                        */
+                       if (notify_sibling_rt || ins == &fn->leaf)
+                               err = call_fib6_entry_notifiers(info->nl_net,
+                                                               fib_event, rt,
+                                                               extack);
+
                        err = call_fib6_entry_notifiers(info->nl_net,
                                                        FIB_EVENT_ENTRY_ADD,
                                                        rt, extack);