From 2ce297fc24d1f0b70c756d1f593e7a089a2d888d Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 10 Dec 2012 02:15:35 +0000 Subject: [PATCH] bridge: fix seq check in br_mdb_dump() In case of rehashing, introduce a global variable 'br_mdb_rehash_seq' which gets increased every time when rehashing, and assign net->dev_base_seq + br_mdb_rehash_seq to cb->seq. In theory cb->seq could be wrapped to zero, but this is not easy to fix, as net->dev_base_seq is not visible inside br_mdb_rehash(). In practice, this is rare. Cc: Herbert Xu Cc: Stephen Hemminger Cc: "David S. Miller" Cc: Thomas Graf Cc: Jesper Dangaard Brouer Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/bridge/br_mdb.c | 6 ++---- net/bridge/br_multicast.c | 2 ++ net/bridge/br_private.h | 1 + 3 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/bridge/br_mdb.c b/net/bridge/br_mdb.c index edc0d731f6b2..ccc43a9bff80 100644 --- a/net/bridge/br_mdb.c +++ b/net/bridge/br_mdb.c @@ -117,10 +117,8 @@ static int br_mdb_dump(struct sk_buff *skb, struct netlink_callback *cb) rcu_read_lock(); - /* TODO: in case of rehashing, we need to check - * consistency for dumping. - */ - cb->seq = net->dev_base_seq; + /* In theory this could be wrapped to 0... */ + cb->seq = net->dev_base_seq + br_mdb_rehash_seq; for_each_netdev_rcu(net, dev) { if (dev->priv_flags & IFF_EBRIDGE) { diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 68e375ac93bd..847b98a1d5e0 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -37,6 +37,7 @@ rcu_dereference_protected(X, lockdep_is_held(&br->multicast_lock)) static void br_multicast_start_querier(struct net_bridge *br); +unsigned int br_mdb_rehash_seq; #if IS_ENABLED(CONFIG_IPV6) static inline int ipv6_is_transient_multicast(const struct in6_addr *addr) @@ -338,6 +339,7 @@ static int br_mdb_rehash(struct net_bridge_mdb_htable __rcu **mdbp, int max, return err; } + br_mdb_rehash_seq++; call_rcu_bh(&mdb->rcu, br_mdb_free); out: diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index ae0a6ec0a702..f95b766c7a98 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -411,6 +411,7 @@ extern int br_ioctl_deviceless_stub(struct net *net, unsigned int cmd, void __us /* br_multicast.c */ #ifdef CONFIG_BRIDGE_IGMP_SNOOPING +extern unsigned int br_mdb_rehash_seq; extern int br_multicast_rcv(struct net_bridge *br, struct net_bridge_port *port, struct sk_buff *skb);