From: Ido Schimmel <ido...@mellanox.com>
The next patch will enable listeners of the FIB notification chain to
request a dump of the FIB tables. However, since RTNL isn't taken during
the dump, it's possible for the FIB tables to change mid-dump, which
will result in inconsistency between the listener's table and the
kernel's.
Allow listeners to know about changes that occurred mid-dump, by adding
a change sequence counter to each net namespace. The counter is
incremented just before a notification is sent in the FIB chain.
Signed-off-by: Ido Schimmel <ido...@mellanox.com>
Signed-off-by: Jiri Pirko <j...@mellanox.com>
---
include/net/netns/ipv4.h | 2 ++
net/ipv4/fib_frontend.c | 2 ++
net/ipv4/fib_trie.c | 1 +
3 files changed, 5 insertions(+)
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 7adf438..d236c08 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -136,5 +136,7 @@ struct netns_ipv4 {
int sysctl_fib_multipath_use_neigh;
#endif
atomic_t rt_genid;
+
+ atomic_t fib_seq;
};
#endif
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 121384b..cf8c867 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1219,6 +1219,8 @@ static int __net_init ip_fib_net_init(struct net *net)
int err;
size_t size = sizeof(struct hlist_head) * FIB_TABLE_HASHSZ;
+ atomic_set(&net->ipv4.fib_seq, 0);
+
/* Avoid false sharing : Use at least a full cache line */
size = max_t(size_t, size, L1_CACHE_BYTES);
diff --git a/net/ipv4/fib_trie.c b/net/ipv4/fib_trie.c
index 9bfce0d..b1d2d09 100644
--- a/net/ipv4/fib_trie.c
+++ b/net/ipv4/fib_trie.c
@@ -101,6 +101,7 @@ EXPORT_SYMBOL(unregister_fib_notifier);
int call_fib_notifiers(struct net *net, enum fib_event_type event_type,
struct fib_notifier_info *info)
{
+ atomic_inc(&net->ipv4.fib_seq);
info->net = net;
return atomic_notifier_call_chain(&fib_chain, event_type, info);
}
--
2.7.4
