From: Vlad Yasevich Date: Thu, 10 Oct 2013 19:57:59 +0000 (-0400) Subject: bridge: update mdb expiration timer upon reports. X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f144febd93d5ee534fdf23505ab091b2b9088edc;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git bridge: update mdb expiration timer upon reports. commit 9f00b2e7cf241fa389733d41b615efdaa2cb0f5b bridge: only expire the mdb entry when query is received changed the mdb expiration timer to be armed only when QUERY is received. Howerver, this causes issues in an environment where the multicast server socket comes and goes very fast while a client is trying to send traffic to it. The root cause is a race where a sequence of LEAVE followed by REPORT messages can race against QUERY messages generated in response to LEAVE. The QUERY ends up starting the expiration timer, and that timer can potentially expire after the new REPORT message has been received signaling the new join operation. This leads to a significant drop in multicast traffic and possible complete stall. The solution is to have REPORT messages update the expiration timer on entries that already exist. CC: Cong Wang CC: Herbert Xu CC: Stephen Hemminger Signed-off-by: Vlad Yasevich Acked-by: Herbert Xu Signed-off-by: David S. Miller --- diff --git a/net/bridge/br_multicast.c b/net/bridge/br_multicast.c index d1c578630678..1085f2180f3a 100644 --- a/net/bridge/br_multicast.c +++ b/net/bridge/br_multicast.c @@ -611,6 +611,9 @@ rehash: break; default: + /* If we have an existing entry, update it's expire timer */ + mod_timer(&mp->timer, + jiffies + br->multicast_membership_interval); goto out; } @@ -680,8 +683,12 @@ static int br_multicast_add_group(struct net_bridge *br, for (pp = &mp->ports; (p = mlock_dereference(*pp, br)) != NULL; pp = &p->next) { - if (p->port == port) + if (p->port == port) { + /* We already have a portgroup, update the timer. */ + mod_timer(&p->timer, + jiffies + br->multicast_membership_interval); goto out; + } if ((unsigned long)p->port < (unsigned long)port) break; }