[NET] fib_rules: Flush route cache after rule modifications

The results of FIB rules lookups are cached in the routing cache
except for IPv6 as no such cache exists. So far, it was the
responsibility of the user to flush the cache after modifying any
rules. This lead to many false bug reports due to misunderstanding
of this concept.

This patch automatically flushes the route cache after inserting
or deleting a rule.

Thanks to Muli Ben-Yehuda <muli@il.ibm.com> for catching a bug
in the previous patch.

Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 0 deletions

diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c
index 5824b2644f26..cb2dae19531b 100644
--- a/net/core/fib_rules.c
+++ b/net/core/fib_rules.c
@@ -44,6 +44,12 @@ static void rules_ops_put(struct fib_rules_ops *ops)
                 module_put(ops->owner);
 }
 
+static void flush_route_cache(struct fib_rules_ops *ops)
+{
+        if (ops->flush_cache)
+                ops->flush_cache();
+}
+
 int fib_rules_register(struct fib_rules_ops *ops)
 {
         int err = -EEXIST;
@@ -314,6 +320,7 @@ static int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                 list_add_rcu(&rule->list, ops->rules_list);
 
         notify_rule_change(RTM_NEWRULE, rule, ops, nlh, NETLINK_CB(skb).pid);
+        flush_route_cache(ops);
         rules_ops_put(ops);
         return 0;
 
@@ -404,6 +411,7 @@ static int fib_nl_delrule(struct sk_buff *skb, struct nlmsghdr* nlh, void *arg)
                 notify_rule_change(RTM_DELRULE, rule, ops, nlh,
                                    NETLINK_CB(skb).pid);
                 fib_rule_put(rule);
+                flush_route_cache(ops);
                 rules_ops_put(ops);
                 return 0;
         }