bonding: Send more than one gratuitous ARP when slave takes over
With IPoIB, reception of gratuitous ARP by neighboring hosts
is essential for a successful change of slaves in case of failure.
Otherwise, they won't learn about the HW address change and need
to wait a long time until the neighboring system gives up and sends
an ARP request to learn the new HW address. This patch decreases
the chance for a lost of a gratuitous ARP packet by sending it more
than once. The number retries is configurable and can be set with a
module param.
Signed-off-by: Moni Shoua <monis@voltaire.com>
Acked-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 1f02857..7a61e9a 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -951,6 +951,45 @@
static DEVICE_ATTR(lacp_rate, S_IRUGO | S_IWUSR, bonding_show_lacp, bonding_store_lacp);
/*
+ * Show and set the number of grat ARP to send after a failover event.
+ */
+static ssize_t bonding_show_n_grat_arp(struct device *d,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct bonding *bond = to_bond(d);
+
+ return sprintf(buf, "%d\n", bond->params.num_grat_arp);
+}
+
+static ssize_t bonding_store_n_grat_arp(struct device *d,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ int new_value, ret = count;
+ struct bonding *bond = to_bond(d);
+
+ if (sscanf(buf, "%d", &new_value) != 1) {
+ printk(KERN_ERR DRV_NAME
+ ": %s: no num_grat_arp value specified.\n",
+ bond->dev->name);
+ ret = -EINVAL;
+ goto out;
+ }
+ if (new_value < 0 || new_value > 255) {
+ printk(KERN_ERR DRV_NAME
+ ": %s: Invalid num_grat_arp value %d not in range 0-255; rejected.\n",
+ bond->dev->name, new_value);
+ ret = -EINVAL;
+ goto out;
+ } else {
+ bond->params.num_grat_arp = new_value;
+ }
+out:
+ return ret;
+}
+static DEVICE_ATTR(num_grat_arp, S_IRUGO | S_IWUSR, bonding_show_n_grat_arp, bonding_store_n_grat_arp);
+/*
* Show and set the MII monitor interval. There are two tricky bits
* here. First, if MII monitoring is activated, then we must disable
* ARP monitoring. Second, if the timer isn't running, we must
@@ -1387,6 +1426,7 @@
&dev_attr_updelay.attr,
&dev_attr_lacp_rate.attr,
&dev_attr_xmit_hash_policy.attr,
+ &dev_attr_num_grat_arp.attr,
&dev_attr_miimon.attr,
&dev_attr_primary.attr,
&dev_attr_use_carrier.attr,