Re: [PATCH] bonding: allow bond in mode balance-alb to work properly in bridge -try2

Jiri Pirko
2009-03-25T14:42:05Z

Wed, Mar 25, 2009 at 02:40:43PM CET, dada1@cosmosbay.com wrote:
>Jiri Pirko a écrit :
>> (resend)
>>
>> Hi all.
>>
>> The problem is described in following bugzilla:
>> https://bugzilla.redhat.com/show_bug.cgi?id=487763
>>
>> Basically here's what's going on. In every mode, bonding interface uses the same
>> mac address for all enslaved devices. Except for mode balance-alb. When you put
>> this kind of bond device into a bridge it will only add one of mac adresses into
>> a hash list of mac addresses, say X. This mac address is marked as local. But
>> this bonding interface also has mac address Y. Now then packet arrives with
>> destination address Y, this address is not marked as local and the packed looks
>> like it needs to be forwarded. This packet is then lost which is wrong.
>>
>> Notice that interfaces can be added and removed from bond while it is in bridge.
>>
>> This patch solves the situation in the bonding without touching bridge code,
>> as Patrick suggested. For every incoming frame to bonding it searches the
>> destination address in slaves list and if any of slave addresses matches, it
>> rewrites the address in frame by the adress of bonding master. This ensures that
>> all frames comming thru the bonding in alb mode have the same address.
>>
>> Jirka
>>
>>
>> Signed-off-by: Jiri Pirko <jpirko@redhat.com>
>>
>> diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>> index 27fb7f5..2838be0 100644
>> --- a/drivers/net/bonding/bond_alb.c
>> +++ b/drivers/net/bonding/bond_alb.c
>> @@ -1762,6 +1762,26 @@ int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
>> return 0;
>> }
>>
>> +void bond_alb_change_dest(struct sk_buff *skb)
>> +{
>> + struct net_device *bond_dev = skb->dev;
>> + struct bonding *bond = netdev_priv(bond_dev);
>> + unsigned char *dest = eth_hdr(skb)->h_dest;
>> + struct slave *slave;
>> + int i;
>> +
>> + if (!memcmp(dest, bond_dev->dev_addr, ETH_ALEN))
>> + return;
>> + read_lock(&bond->lock);
>
>
>Its a pity bonding doesnt use RCU and needs this read_lock(&bond->lock)

Sure it is...
>
>
>> + bond_for_each_slave(bond, slave, i) {
>> + if (!memcmp(slave->dev->dev_addr, dest, ETH_ALEN)) {
>
>compare_ether_addr() (or even better compare_ether_addr_64bits()) instead of memcmp() ?

Okay, I'll use compare_ether_addr_64bits and do the repost later on...
>
>> + memcpy(dest, bond_dev->dev_addr, ETH_ALEN);
>> + break;
>> + }
>> + }
>> + read_unlock(&bond->lock);
>> +}
>> +
>