Re: [PATCH net V2] bonding: send igmp report for its master

From: Andy Gospodarek
Date: Wed Mar 14 2012 - 13:21:47 EST


On Wed, Mar 14, 2012 at 11:37:22AM +0800, Weiping Pan wrote:
> Liang Zheng(lzheng@xxxxxxxxxx) found that in the following topo,
> bonding does not send igmp report when we trigger a fail-over of bonding.
>
> eth0--
> |-- bond0 -- br0
> eth1--
>
> modprobe bonding mode=1 miimon=100 resend_igmp=10
> ifconfig bond0 up
> ifenslave bond0 eth0 eth1
>
> brctl addbr br0
> ifconfig br0 192.168.100.2/24 up
> brctl addif br0 bond0
>
> Add 192.168.100.2(br0) into a multicast group, like 224.10.10.10,
> then trigger a fali-over in bonding.
> You can see that parameter "resend_igmp" does not work.
>
> The reason is that when we add br0 into a multicast group,
> it does not propagate multicast knowledge down to its ports.
>
> If we choose to propagate multicast knowledge down to all ports for bridge,
> then we have to track every change that is done to bridge, and keep a backup
> for all ports. It is hard to track, I think.
>
> Instead I choose to modify bonding to send igmp report for its master.
>
> Changelog:
> V2: correct comments
>
> Signed-off-by: Weiping Pan <panweiping3@xxxxxxxxx>
> ---
> drivers/net/bonding/bond_main.c | 8 ++++++++
> 1 files changed, 8 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> index 435984a..300c490 100644
> --- a/drivers/net/bonding/bond_main.c
> +++ b/drivers/net/bonding/bond_main.c
> @@ -794,6 +794,14 @@ static void bond_resend_igmp_join_requests_delayed(struct work_struct *work)
> {
> struct bonding *bond = container_of(work, struct bonding,
> mcast_work.work);
> + struct net_device *bond_dev, *master_dev = NULL;
> + bond_dev = bond->dev;
> + master_dev = bond_dev->master;
> +
> + if (unlikely(master_dev)) {
> + __bond_resend_igmp_join_requests(master_dev);
> + }
> +
> bond_resend_igmp_join_requests(bond);
> }
>

This check and call to __bond_resend_igmp_join_requests would be better
in bond_resend_igmp_join_requests for 2 reasons:

1. bond_resend_igmp_join_requests already has a check for vlan devices.
It seems logical to check for the bridging case there also.

2. Calling __bond_resend_igmp_join_requests will not work as expected
when igmp_retrans>1 since no decrementing or rescheduling is done in
__bond_resend_igmp_join_requests.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/