bonding: gratuitous ARP
Add support for generating gratuitous ARPs in bonding
active-backup mode when failovers occur. Includes support for VLAN
tagging the ARPs as needed.
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 269a5e4..545f6fe 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -475,7 +475,10 @@
* Solution is to move call to dev_remove_pack outside of the
* spinlock.
* Set version to 2.6.1.
- *
+ * 2005/06/05 - Jay Vosburgh <fubar@us.ibm.com>
+ * - Support for generating gratuitous ARPs in active-backup mode.
+ * Includes support for VLAN tagging all bonding-generated ARPs
+ * as needed. Set version to 2.6.2.
*/
//#define BONDING_DEBUG 1
@@ -519,6 +522,7 @@
#include <linux/ethtool.h>
#include <linux/if_vlan.h>
#include <linux/if_bonding.h>
+#include <net/route.h>
#include "bonding.h"
#include "bond_3ad.h"
#include "bond_alb.h"
@@ -574,7 +578,6 @@
static u32 arp_target[BOND_MAX_ARP_TARGETS] = { 0, } ;
static int arp_ip_count = 0;
-static u32 my_ip = 0;
static int bond_mode = BOND_MODE_ROUNDROBIN;
static int lacp_fast = 0;
static int app_abi_ver = 0;
@@ -611,6 +614,7 @@
/*-------------------------- Forward declarations ---------------------------*/
static inline void bond_set_mode_ops(struct net_device *bond_dev, int mode);
+static void bond_send_gratuitous_arp(struct bonding *bond);
/*---------------------------- General routines -----------------------------*/
@@ -659,6 +663,7 @@
INIT_LIST_HEAD(&vlan->vlan_list);
vlan->vlan_id = vlan_id;
+ vlan->vlan_ip = 0;
write_lock_bh(&bond->lock);
@@ -1468,16 +1473,6 @@
}
}
- if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
- if (old_active) {
- bond_set_slave_inactive_flags(old_active);
- }
-
- if (new_active) {
- bond_set_slave_active_flags(new_active);
- }
- }
-
if (USES_PRIMARY(bond->params.mode)) {
bond_mc_swap(bond, new_active, old_active);
}
@@ -1488,6 +1483,17 @@
} else {
bond->curr_active_slave = new_active;
}
+
+ if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
+ if (old_active) {
+ bond_set_slave_inactive_flags(old_active);
+ }
+
+ if (new_active) {
+ bond_set_slave_active_flags(new_active);
+ }
+ bond_send_gratuitous_arp(bond);
+ }
}
/**
@@ -2694,15 +2700,180 @@
read_unlock(&bond->lock);
}
+
+static u32 bond_glean_dev_ip(struct net_device *dev)
+{
+ struct in_device *idev;
+ struct in_ifaddr *ifa;
+ u32 addr = 0;
+
+ if (!dev)
+ return 0;
+
+ rcu_read_lock();
+ idev = __in_dev_get(dev);
+ if (!idev)
+ goto out;
+
+ ifa = idev->ifa_list;
+ if (!ifa)
+ goto out;
+
+ addr = ifa->ifa_local;
+out:
+ rcu_read_unlock();
+ return addr;
+}
+
+static int bond_has_ip(struct bonding *bond)
+{
+ struct vlan_entry *vlan, *vlan_next;
+
+ if (bond->master_ip)
+ return 1;
+
+ if (list_empty(&bond->vlan_list))
+ return 0;
+
+ list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
+ vlan_list) {
+ if (vlan->vlan_ip)
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * We go to the (large) trouble of VLAN tagging ARP frames because
+ * switches in VLAN mode (especially if ports are configured as
+ * "native" to a VLAN) might not pass non-tagged frames.
+ */
+static void bond_arp_send(struct net_device *slave_dev, int arp_op, u32 dest_ip, u32 src_ip, unsigned short vlan_id)
+{
+ struct sk_buff *skb;
+
+ dprintk("arp %d on slave %s: dst %x src %x vid %d\n", arp_op,
+ slave_dev->name, dest_ip, src_ip, vlan_id);
+
+ skb = arp_create(arp_op, ETH_P_ARP, dest_ip, slave_dev, src_ip,
+ NULL, slave_dev->dev_addr, NULL);
+
+ if (!skb) {
+ printk(KERN_ERR DRV_NAME ": ARP packet allocation failed\n");
+ return;
+ }
+ if (vlan_id) {
+ skb = vlan_put_tag(skb, vlan_id);
+ if (!skb) {
+ printk(KERN_ERR DRV_NAME ": failed to insert VLAN tag\n");
+ return;
+ }
+ }
+ arp_xmit(skb);
+}
+
+
static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
{
- int i;
+ int i, vlan_id, rv;
u32 *targets = bond->params.arp_targets;
+ struct vlan_entry *vlan, *vlan_next;
+ struct net_device *vlan_dev;
+ struct flowi fl;
+ struct rtable *rt;
for (i = 0; (i < BOND_MAX_ARP_TARGETS) && targets[i]; i++) {
- arp_send(ARPOP_REQUEST, ETH_P_ARP, targets[i], slave->dev,
- my_ip, NULL, slave->dev->dev_addr,
- NULL);
+ dprintk("basa: target %x\n", targets[i]);
+ if (list_empty(&bond->vlan_list)) {
+ dprintk("basa: empty vlan: arp_send\n");
+ bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
+ bond->master_ip, 0);
+ continue;
+ }
+
+ /*
+ * If VLANs are configured, we do a route lookup to
+ * determine which VLAN interface would be used, so we
+ * can tag the ARP with the proper VLAN tag.
+ */
+ memset(&fl, 0, sizeof(fl));
+ fl.fl4_dst = targets[i];
+ fl.fl4_tos = RTO_ONLINK;
+
+ rv = ip_route_output_key(&rt, &fl);
+ if (rv) {
+ if (net_ratelimit()) {
+ printk(KERN_WARNING DRV_NAME
+ ": %s: no route to arp_ip_target %u.%u.%u.%u\n",
+ bond->dev->name, NIPQUAD(fl.fl4_dst));
+ }
+ continue;
+ }
+
+ /*
+ * This target is not on a VLAN
+ */
+ if (rt->u.dst.dev == bond->dev) {
+ dprintk("basa: rtdev == bond->dev: arp_send\n");
+ bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
+ bond->master_ip, 0);
+ continue;
+ }
+
+ vlan_id = 0;
+ list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
+ vlan_list) {
+ vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+ if (vlan_dev == rt->u.dst.dev) {
+ vlan_id = vlan->vlan_id;
+ dprintk("basa: vlan match on %s %d\n",
+ vlan_dev->name, vlan_id);
+ break;
+ }
+ }
+
+ if (vlan_id) {
+ bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
+ vlan->vlan_ip, vlan_id);
+ continue;
+ }
+
+ if (net_ratelimit()) {
+ printk(KERN_WARNING DRV_NAME
+ ": %s: no path to arp_ip_target %u.%u.%u.%u via rt.dev %s\n",
+ bond->dev->name, NIPQUAD(fl.fl4_dst),
+ rt->u.dst.dev ? rt->u.dst.dev->name : "NULL");
+ }
+ }
+}
+
+/*
+ * Kick out a gratuitous ARP for an IP on the bonding master plus one
+ * for each VLAN above us.
+ */
+static void bond_send_gratuitous_arp(struct bonding *bond)
+{
+ struct slave *slave = bond->curr_active_slave;
+ struct vlan_entry *vlan;
+ struct net_device *vlan_dev;
+
+ dprintk("bond_send_grat_arp: bond %s slave %s\n", bond->dev->name,
+ slave ? slave->dev->name : "NULL");
+ if (!slave)
+ return;
+
+ if (bond->master_ip) {
+ bond_arp_send(slave->dev, ARPOP_REPLY, bond->master_ip,
+ bond->master_ip, 0);
+ }
+
+ list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
+ vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+ if (vlan->vlan_ip) {
+ bond_arp_send(slave->dev, ARPOP_REPLY, vlan->vlan_ip,
+ vlan->vlan_ip, vlan->vlan_id);
+ }
}
}
@@ -2781,7 +2952,7 @@
*/
if (((jiffies - slave->dev->trans_start) >= (2*delta_in_ticks)) ||
(((jiffies - slave->dev->last_rx) >= (2*delta_in_ticks)) &&
- my_ip)) {
+ bond_has_ip(bond))) {
slave->link = BOND_LINK_DOWN;
slave->state = BOND_STATE_BACKUP;
@@ -2920,7 +3091,7 @@
if ((slave != bond->curr_active_slave) &&
(!bond->current_arp_slave) &&
(((jiffies - slave->dev->last_rx) >= 3*delta_in_ticks) &&
- my_ip)) {
+ bond_has_ip(bond))) {
/* a backup slave has gone down; three times
* the delta allows the current slave to be
* taken out before the backup slave.
@@ -2966,8 +3137,8 @@
* if it is up and needs to take over as the curr_active_slave
*/
if ((((jiffies - slave->dev->trans_start) >= (2*delta_in_ticks)) ||
- (((jiffies - slave->dev->last_rx) >= (2*delta_in_ticks)) &&
- my_ip)) &&
+ (((jiffies - slave->dev->last_rx) >= (2*delta_in_ticks)) &&
+ bond_has_ip(bond))) &&
((jiffies - slave->jiffies) >= 2*delta_in_ticks)) {
slave->link = BOND_LINK_DOWN;
@@ -3019,7 +3190,7 @@
/* the current slave must tx an arp to ensure backup slaves
* rx traffic
*/
- if (slave && my_ip) {
+ if (slave && bond_has_ip(bond)) {
bond_arp_send_all(bond, slave);
}
}
@@ -3471,10 +3642,67 @@
return NOTIFY_DONE;
}
+/*
+ * bond_inetaddr_event: handle inetaddr notifier chain events.
+ *
+ * We keep track of device IPs primarily to use as source addresses in
+ * ARP monitor probes (rather than spewing out broadcasts all the time).
+ *
+ * We track one IP for the main device (if it has one), plus one per VLAN.
+ */
+static int bond_inetaddr_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+ struct in_ifaddr *ifa = ptr;
+ struct net_device *vlan_dev, *event_dev = ifa->ifa_dev->dev;
+ struct bonding *bond, *bond_next;
+ struct vlan_entry *vlan, *vlan_next;
+
+ list_for_each_entry_safe(bond, bond_next, &bond_dev_list, bond_list) {
+ if (bond->dev == event_dev) {
+ switch (event) {
+ case NETDEV_UP:
+ bond->master_ip = ifa->ifa_local;
+ return NOTIFY_OK;
+ case NETDEV_DOWN:
+ bond->master_ip = bond_glean_dev_ip(bond->dev);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+ }
+
+ if (list_empty(&bond->vlan_list))
+ continue;
+
+ list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
+ vlan_list) {
+ vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+ if (vlan_dev == event_dev) {
+ switch (event) {
+ case NETDEV_UP:
+ vlan->vlan_ip = ifa->ifa_local;
+ return NOTIFY_OK;
+ case NETDEV_DOWN:
+ vlan->vlan_ip =
+ bond_glean_dev_ip(vlan_dev);
+ return NOTIFY_OK;
+ default:
+ return NOTIFY_DONE;
+ }
+ }
+ }
+ }
+ return NOTIFY_DONE;
+}
+
static struct notifier_block bond_netdev_notifier = {
.notifier_call = bond_netdev_event,
};
+static struct notifier_block bond_inetaddr_notifier = {
+ .notifier_call = bond_inetaddr_event,
+};
+
/*-------------------------- Packet type handling ---------------------------*/
/* register to receive lacpdus on a bond */
@@ -4060,17 +4288,6 @@
struct bonding *bond = bond_dev->priv;
int res = 1;
- /* if we are sending arp packets, try to at least
- identify our own ip address */
- if (bond->params.arp_interval && !my_ip &&
- (skb->protocol == __constant_htons(ETH_P_ARP))) {
- char *the_ip = (char *)skb->data +
- sizeof(struct ethhdr) +
- sizeof(struct arphdr) +
- ETH_ALEN;
- memcpy(&my_ip, the_ip, 4);
- }
-
read_lock(&bond->lock);
read_lock(&bond->curr_slave_lock);
@@ -4669,6 +4886,7 @@
rtnl_unlock();
register_netdevice_notifier(&bond_netdev_notifier);
+ register_inetaddr_notifier(&bond_inetaddr_notifier);
return 0;
@@ -4684,6 +4902,7 @@
static void __exit bonding_exit(void)
{
unregister_netdevice_notifier(&bond_netdev_notifier);
+ unregister_inetaddr_notifier(&bond_inetaddr_notifier);
rtnl_lock();
bond_free_all();