From mboxrd@z Thu Jan 1 00:00:00 1970 From: Cong Wang Subject: [Patch net-next v2] bridge: do not expire mdb entry as long as bridge still uses it Date: Thu, 25 Apr 2013 16:21:23 +0800 Message-ID: <1366878083-22797-1-git-send-email-amwang@redhat.com> Cc: Herbert Xu , Stephen Hemminger , "David S. Miller" , Adam Baker , Cong Wang To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42244 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756045Ab3DYIVx (ORCPT ); Thu, 25 Apr 2013 04:21:53 -0400 Sender: netdev-owner@vger.kernel.org List-ID: This bug can be observed in virt environment, when a KVM guest communicates with the host via multicast. After some time (should be 260 sec, I didn't measure), the multicast traffic suddenly terminates. This is due to the mdb entry for bridge itself expires automatically, it should not expire as long as the bridge still generates multicast traffic. It should expire when the bridge leaves the multicast group, OR when there is no multicast traffic on this bridge. I fix this by adding another bool which is set when there is multicast traffic goes to the bridge, cleared in the expire timer and when IGMP leave is received. I ran omping for 15 minutes, everything looks good now. This might not be the best fix, but might be the simplest fix. (Adam, this problem is probably different with your problem, at least this problem can _not_ be workarounded by setting querier to 1.) Cc: Herbert Xu Cc: Stephen Hemminger Cc: "David S. Miller" Cc: Adam Baker Signed-off-by: Cong Wang --- v2: rename ->busy to ->for_br diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c index 828e2bc..4f0e50f 100644 --- a/net/bridge/br_input.c +++ b/net/bridge/br_input.c @@ -99,9 +99,12 @@ int br_handle_frame_finish(struct sk_buff *skb) else if (is_multicast_ether_addr(dest)) { mdst = br_mdb_get(br, skb, vid); if (mdst || BR_INPUT_SKB_CB_MROUTERS_ONLY(skb)) { - if ((mdst && mdst->mglist) || - br_multicast_is_router(br)) + bool to_br = mdst && mdst->mglist; + if (to_br || br_multicast_is_router(br)) skb2 = skb; + /* Hold this mdb entry for bridge itself */ + if (to_br) + mdst->for_br = true; br_multicast_forward(mdst, skb, skb2); skb = NULL; if (!skb2) diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index 81f2389..a86aa42 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -228,11 +228,16 @@ static void br_multicast_group_expired(unsigned long data) if (!netif_running(br->dev) || timer_pending(&mp->timer)) goto out; - mp->mglist = false; - if (mp->ports) goto out; + if (mp->mglist && mp->for_br) { + mp->for_br = false; + goto out; + } + + mp->mglist = false; + mdb = mlock_dereference(br->mdb, br); hlist_del_rcu(&mp->hlist[mdb->ver]); @@ -668,7 +673,7 @@ static int br_multicast_add_group(struct net_bridge *br, goto err; if (!port) { - mp->mglist = true; + mp->mglist = mp->for_br = true; mod_timer(&mp->timer, now + br->multicast_membership_interval); goto out; } @@ -1280,6 +1285,7 @@ static void br_multicast_leave_group(struct net_bridge *br, mod_timer(&mp->timer, time); } + mp->for_br = false; goto out; } diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h index d2c043a..c96bf19 100644 --- a/net/bridge/br_private.h +++ b/net/bridge/br_private.h @@ -112,6 +112,7 @@ struct net_bridge_mdb_entry struct timer_list timer; struct br_ip addr; bool mglist; + bool for_br; /* update this only when mglist == true */ }; struct net_bridge_mdb_htable