2012-11-12 09:52:31

by zheng.li

Subject: [PATCH] bonding: rlb mode of bond should not alter ARP replies originating via bridge

ARP traffic passing through a bridge and out via the bond (when the bond is a
port of the bridge) should not have its source MAC address adjusted by the
receive load balance code in rlb_arp_xmit.

Signed-off-by: Zheng Li <[email protected]>
Cc: Jay Vosburgh <[email protected]>
Cc: Andy Gospodarek <[email protected]>
Cc: "David S. Miller" <[email protected]>

---
drivers/net/bonding/bond_alb.c | 21 ++++++++++++++++++++-
1 files changed, 20 insertions(+), 1 deletions(-)

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index e15cc11..a99e658 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -685,6 +685,18 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
return assigned_slave;
}

+struct slave *bond_slave_has_mac(struct bonding *bond, const u8 *mac)
+{
+ int i = 0;
+ struct slave *tmp;
+
+ bond_for_each_slave(bond, tmp, i)
+ if (ether_addr_equal_64bits(mac, tmp->dev->dev_addr))
+ return tmp;
+
+ return NULL;
+}
+
/* chooses (and returns) transmit channel for arp reply
* does not choose channel for other arp types since they are
* sent on the curr_active_slave
@@ -700,7 +712,14 @@ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond)
*/
tx_slave = rlb_choose_channel(skb, bond);
if (tx_slave) {
- memcpy(arp->mac_src,tx_slave->dev->dev_addr, ETH_ALEN);
+ struct slave *tmp_slave = NULL;
+ /* Only modify ARP's MAC if it originates locally;
+ * don't change ARPs arriving via a bridge.
+ */
+ tmp_slave = bond_slave_has_mac(bond, arp->mac_src);
+ if (tmp_slave)
+ memcpy(arp->mac_src, tx_slave->dev->dev_addr,
+ ETH_ALEN);
}
pr_debug("Server sent ARP Reply packet\n");
} else if (arp->op_code == htons(ARPOP_REQUEST)) {
--
1.7.6.5

2012-11-12 23:40:54

by Jay Vosburgh

Subject: Re: [PATCH] bonding: rlb mode of bond should not alter ARP replies originating via bridge

Zheng Li <[email protected]> wrote:

>ARP traffic passing through a bridge and out via the bond (when the bond is a
>port of the bridge) should not have its source MAC address adjusted by the
>receive load balance code in rlb_arp_xmit.
>
>Signed-off-by: Zheng Li <[email protected]>
>Cc: Jay Vosburgh <[email protected]>
>Cc: Andy Gospodarek <[email protected]>
>Cc: "David S. Miller" <[email protected]>
>
>---
> drivers/net/bonding/bond_alb.c | 21 ++++++++++++++++++++-
> 1 files changed, 20 insertions(+), 1 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>index e15cc11..a99e658 100644
>--- a/drivers/net/bonding/bond_alb.c
>+++ b/drivers/net/bonding/bond_alb.c
>@@ -685,6 +685,18 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
> return assigned_slave;
> }
>
>+struct slave *bond_slave_has_mac(struct bonding *bond, const u8 *mac)
>+{
>+ int i = 0;
>+ struct slave *tmp;
>+
>+ bond_for_each_slave(bond, tmp, i)
>+ if (ether_addr_equal_64bits(mac, tmp->dev->dev_addr))
>+ return tmp;
>+
>+ return NULL;
>+}

This should go in bonding.h as a static line, so that other
parts of bonding can use it in the future. I'll also point out that
this function is one I suggested in a prior email, but did not test.
Presumably you've tested this.

> /* chooses (and returns) transmit channel for arp reply
> * does not choose channel for other arp types since they are
> * sent on the curr_active_slave
>@@ -700,7 +712,14 @@ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond)
> */
> tx_slave = rlb_choose_channel(skb, bond);
> if (tx_slave) {
>- memcpy(arp->mac_src,tx_slave->dev->dev_addr, ETH_ALEN);
>+ struct slave *tmp_slave = NULL;

This does not need to be initialized, as the next line of code
assigns a value to it.

-J

>+ /* Only modify ARP's MAC if it originates locally;
>+ * don't change ARPs arriving via a bridge.
>+ */
>+ tmp_slave = bond_slave_has_mac(bond, arp->mac_src);
>+ if (tmp_slave)
>+ memcpy(arp->mac_src, tx_slave->dev->dev_addr,
>+ ETH_ALEN);
> }
> pr_debug("Server sent ARP Reply packet\n");
> } else if (arp->op_code == htons(ARPOP_REQUEST)) {
>--
>1.7.6.5

---
-Jay Vosburgh, IBM Linux Technology Center, [email protected]