[PATCH] bonding: Validate probe replies in ARP monitor

	Add logic to check ARP request / reply packets used for ARP
monitor link integrity checking.

	The current method simply examines the slave device to see if it
has sent and received traffic; this can be fooled by extraneous traffic.
For example, if multiple hosts running bonding are behind a common
switch, the probe traffic from the multiple instances of bonding will
update the tx/rx times on each other's slave devices.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 54 insertions, 0 deletions

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 15b6a29bb4d..ced9ed8f995 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -51,6 +51,7 @@ extern struct bond_params bonding_defaults;
 extern struct bond_parm_tbl bond_mode_tbl[];
 extern struct bond_parm_tbl bond_lacp_tbl[];
 extern struct bond_parm_tbl xmit_hashtype_tbl[];
+extern struct bond_parm_tbl arp_validate_tbl[];
 
 static int expected_refcount = -1;
 static struct class *netdev_class;
@@ -503,6 +504,53 @@ out:
 static CLASS_DEVICE_ATTR(xmit_hash_policy, S_IRUGO | S_IWUSR, bonding_show_xmit_hash, bonding_store_xmit_hash);
 
 /*
+ * Show and set arp_validate.
+ */
+static ssize_t bonding_show_arp_validate(struct class_device *cd, char *buf)
+{
+	struct bonding *bond = to_bond(cd);
+
+	return sprintf(buf, "%s %d\n",
+		       arp_validate_tbl[bond->params.arp_validate].modename,
+		       bond->params.arp_validate) + 1;
+}
+
+static ssize_t bonding_store_arp_validate(struct class_device *cd, const char *buf, size_t count)
+{
+	int new_value;
+	struct bonding *bond = to_bond(cd);
+
+	new_value = bond_parse_parm((char *)buf, arp_validate_tbl);
+	if (new_value < 0) {
+		printk(KERN_ERR DRV_NAME
+		       ": %s: Ignoring invalid arp_validate value %s\n",
+		       bond->dev->name, buf);
+		return -EINVAL;
+	}
+	if (new_value && (bond->params.mode != BOND_MODE_ACTIVEBACKUP)) {
+		printk(KERN_ERR DRV_NAME
+		       ": %s: arp_validate only supported in active-backup mode.\n",
+		       bond->dev->name);
+		return -EINVAL;
+	}
+	printk(KERN_INFO DRV_NAME ": %s: setting arp_validate to %s (%d).\n",
+	       bond->dev->name, arp_validate_tbl[new_value].modename,
+	       new_value);
+
+	if (!bond->params.arp_validate && new_value) {
+		bond_register_arp(bond);
+	} else if (bond->params.arp_validate && !new_value) {
+		bond_unregister_arp(bond);
+	}
+
+	bond->params.arp_validate = new_value;
+
+	return count;
+}
+
+static CLASS_DEVICE_ATTR(arp_validate, S_IRUGO | S_IWUSR, bonding_show_arp_validate, bonding_store_arp_validate);
+
+/*
  * Show and set the arp timer interval.  There are two tricky bits
  * here.  First, if ARP monitoring is activated, then we must disable
  * MII monitoring.  Second, if the ARP timer isn't running, we must
@@ -914,6 +962,11 @@ static ssize_t bonding_store_miimon(struct class_device *cd, const char *buf, si
 			       "ARP monitoring. Disabling ARP monitoring...\n",
 			       bond->dev->name);
 			bond->params.arp_interval = 0;
+			if (bond->params.arp_validate) {
+				bond_unregister_arp(bond);
+				bond->params.arp_validate =
+					BOND_ARP_VALIDATE_NONE;
+			}
 			/* Kill ARP timer, else it brings bond's link down */
 			if (bond->mii_timer.function) {
 				printk(KERN_INFO DRV_NAME
@@ -1273,6 +1326,7 @@ static CLASS_DEVICE_ATTR(ad_partner_mac, S_IRUGO, bonding_show_ad_partner_mac, N
 static struct attribute *per_bond_attrs[] = {
 	&class_device_attr_slaves.attr,
 	&class_device_attr_mode.attr,
+	&class_device_attr_arp_validate.attr,
 	&class_device_attr_arp_interval.attr,
 	&class_device_attr_arp_ip_target.attr,
 	&class_device_attr_downdelay.attr,