Commit 305d552a authored by Brian Haley's avatar Brian Haley Committed by Jeff Garzik
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bonding: send IPv6 neighbor advertisement on failover 



This patch adds better IPv6 failover support for bonding devices,
especially when in active-backup mode and there are only IPv6 addresses
configured, as reported by Alex Sidorenko.

- Creates a new file, net/drivers/bonding/bond_ipv6.c, for the
   IPv6-specific routines.  Both regular bonds and VLANs over bonds
   are supported.

- Adds a new tunable, num_unsol_na, to limit the number of unsolicited
   IPv6 Neighbor Advertisements that are sent on a failover event.
   Default is 1.

- Creates two new IPv6 neighbor discovery functions:

   ndisc_build_skb()
   ndisc_send_skb()

   These were required to support VLANs since we have to be able to
   add the VLAN id to the skb since ndisc_send_na() and friends
   shouldn't be asked to do this.  These two routines are basically
   __ndisc_send() split into two pieces, in a slightly different order.

- Updates Documentation/networking/bonding.txt and bumps the rev of bond
   support to 3.4.0.

On failover, this new code will generate one packet:

- An unsolicited IPv6 Neighbor Advertisement, which helps the switch
   learn that the address has moved to the new slave.

Testing has shown that sending just the NA results in pretty good
behavior when in active-back mode, I saw no lost ping packets for example.

Signed-off-by: default avatarBrian Haley <brian.haley@hp.com>
Signed-off-by: default avatarJay Vosburgh <fubar@us.ibm.com>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 61c9eaf9

Documentation/networking/bonding.txt

+10 −0
Original line number Diff line number Diff line
@@ -551,6 +551,16 @@ num_grat_arp 
	affects only the active-backup mode.  This option was added for

	bonding version 3.3.0.



num_unsol_na



	Specifies the number of unsolicited IPv6 Neighbor Advertisements

	to be issued after a failover event.  One unsolicited NA is issued

	immediately after the failover.



	The valid range is 0 - 255; the default value is 1.  This option

	affects only the active-backup mode.  This option was added for

	bonding version 3.4.0.



primary



	A string (eth0, eth2, etc) specifying which slave is the

drivers/net/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -61,6 +61,7 @@ config DUMMY 
config BONDING

	tristate "Bonding driver support"

	depends on INET

	depends on IPV6 || IPV6=n

	---help---

	  Say 'Y' or 'M' if you wish to be able to 'bond' multiple Ethernet

	  Channels together. This is called 'Etherchannel' by Cisco,

drivers/net/bonding/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -6,3 +6,6 @@ obj-$(CONFIG_BONDING) += bonding.o 


bonding-objs := bond_main.o bond_3ad.o bond_alb.o bond_sysfs.o



ipv6-$(subst m,y,$(CONFIG_IPV6)) += bond_ipv6.o

bonding-objs += $(ipv6-y)

drivers/net/bonding/bond_ipv6.c

0 → 100644
+218 −0
Original line number Diff line number Diff line 
/*

 * Copyright(c) 2008 Hewlett-Packard Development Company, L.P.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * for more details.

 *

 * You should have received a copy of the GNU General Public License along

 * with this program; if not, write to the Free Software Foundation, Inc.,

 * 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

 *

 * The full GNU General Public License is included in this distribution in the

 * file called LICENSE.

 *

 */



//#define BONDING_DEBUG 1



#include <linux/types.h>

#include <linux/if_vlan.h>

#include <net/ipv6.h>

#include <net/ndisc.h>

#include <net/addrconf.h>

#include "bonding.h"



/*

 * Assign bond->master_ipv6 to the next IPv6 address in the list, or

 * zero it out if there are none.

 */

static void bond_glean_dev_ipv6(struct net_device *dev, struct in6_addr *addr)

{

	struct inet6_dev *idev;

	struct inet6_ifaddr *ifa;



	if (!dev)

		return;



	idev = in6_dev_get(dev);

	if (!idev)

		return;



	read_lock_bh(&idev->lock);

	ifa = idev->addr_list;

	if (ifa)

		ipv6_addr_copy(addr, &ifa->addr);

	else

		ipv6_addr_set(addr, 0, 0, 0, 0);



	read_unlock_bh(&idev->lock);



	in6_dev_put(idev);

}



static void bond_na_send(struct net_device *slave_dev,

			 struct in6_addr *daddr,

			 int router,

			 unsigned short vlan_id)

{

	struct in6_addr mcaddr;

	struct icmp6hdr icmp6h = {

		.icmp6_type = NDISC_NEIGHBOUR_ADVERTISEMENT,

	};

	struct sk_buff *skb;



	icmp6h.icmp6_router = router;

	icmp6h.icmp6_solicited = 0;

	icmp6h.icmp6_override = 1;



	addrconf_addr_solict_mult(daddr, &mcaddr);



	dprintk("ipv6 na on slave %s: dest %pI6, src %pI6\n",

	       slave->name, &mcaddr, daddr);



	skb = ndisc_build_skb(slave_dev, &mcaddr, daddr, &icmp6h, daddr,

			      ND_OPT_TARGET_LL_ADDR);



	if (!skb) {

		printk(KERN_ERR DRV_NAME ": NA 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;

		}

	}



	ndisc_send_skb(skb, slave_dev, NULL, &mcaddr, daddr, &icmp6h);

}



/*

 * Kick out an unsolicited Neighbor Advertisement for an IPv6 address on

 * the bonding master.  This will help the switch learn our address

 * if in active-backup mode.

 *

 * Caller must hold curr_slave_lock for read or better

 */

void bond_send_unsolicited_na(struct bonding *bond)

{

	struct slave *slave = bond->curr_active_slave;

	struct vlan_entry *vlan;

	struct inet6_dev *idev;

	int is_router;



	dprintk("bond_send_unsol_na: bond %s slave %s\n", bond->dev->name,

				slave ? slave->dev->name : "NULL");



	if (!slave || !bond->send_unsol_na ||

	    test_bit(__LINK_STATE_LINKWATCH_PENDING, &slave->dev->state))

		return;



	bond->send_unsol_na--;



	idev = in6_dev_get(bond->dev);

	if (!idev)

		return;



	is_router = !!idev->cnf.forwarding;



	in6_dev_put(idev);



	if (!ipv6_addr_any(&bond->master_ipv6))

		bond_na_send(slave->dev, &bond->master_ipv6, is_router, 0);



	list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {

		if (!ipv6_addr_any(&vlan->vlan_ipv6)) {

			bond_na_send(slave->dev, &vlan->vlan_ipv6, is_router,

				     vlan->vlan_id);

		}

	}

}



/*

 * bond_inet6addr_event: handle inet6addr notifier chain events.

 *

 * We keep track of device IPv6 addresses primarily to use as source

 * addresses in NS probes.

 *

 * We track one IPv6 for the main device (if it has one).

 */

static int bond_inet6addr_event(struct notifier_block *this,

				unsigned long event,

				void *ptr)

{

	struct inet6_ifaddr *ifa = ptr;

	struct net_device *vlan_dev, *event_dev = ifa->idev->dev;

	struct bonding *bond;

	struct vlan_entry *vlan;



	if (dev_net(event_dev) != &init_net)

		return NOTIFY_DONE;



	list_for_each_entry(bond, &bond_dev_list, bond_list) {

		if (bond->dev == event_dev) {

			switch (event) {

			case NETDEV_UP:

				if (ipv6_addr_any(&bond->master_ipv6))

					ipv6_addr_copy(&bond->master_ipv6,

						       &ifa->addr);

				return NOTIFY_OK;

			case NETDEV_DOWN:

				if (ipv6_addr_equal(&bond->master_ipv6,

						    &ifa->addr))

					bond_glean_dev_ipv6(bond->dev,

							    &bond->master_ipv6);

				return NOTIFY_OK;

			default:

				return NOTIFY_DONE;

			}

		}



		list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {

			vlan_dev = vlan_group_get_device(bond->vlgrp,

							 vlan->vlan_id);

			if (vlan_dev == event_dev) {

				switch (event) {

				case NETDEV_UP:

					if (ipv6_addr_any(&vlan->vlan_ipv6))

						ipv6_addr_copy(&vlan->vlan_ipv6,

							       &ifa->addr);

					return NOTIFY_OK;

				case NETDEV_DOWN:

					if (ipv6_addr_equal(&vlan->vlan_ipv6,

							    &ifa->addr))

						bond_glean_dev_ipv6(vlan_dev,

								    &vlan->vlan_ipv6);

					return NOTIFY_OK;

				default:

					return NOTIFY_DONE;

				}

			}

		}

	}

	return NOTIFY_DONE;

}



static struct notifier_block bond_inet6addr_notifier = {

	.notifier_call = bond_inet6addr_event,

};



void bond_register_ipv6_notifier(void)

{

	register_inet6addr_notifier(&bond_inet6addr_notifier);

}



void bond_unregister_ipv6_notifier(void)

{

	unregister_inet6addr_notifier(&bond_inet6addr_notifier);

}

drivers/net/bonding/bond_main.c

+31 −2
Original line number Diff line number Diff line
@@ -89,6 +89,7 @@ 


static int max_bonds	= BOND_DEFAULT_MAX_BONDS;

static int num_grat_arp = 1;

static int num_unsol_na = 1;

static int miimon	= BOND_LINK_MON_INTERV;

static int updelay	= 0;

static int downdelay	= 0;
@@ -107,6 +108,8 @@ module_param(max_bonds, int, 0); 
MODULE_PARM_DESC(max_bonds, "Max number of bonded devices");

module_param(num_grat_arp, int, 0644);

MODULE_PARM_DESC(num_grat_arp, "Number of gratuitous ARP packets to send on failover event");

module_param(num_unsol_na, int, 0644);

MODULE_PARM_DESC(num_unsol_na, "Number of unsolicited IPv6 Neighbor Advertisements packets to send on failover event");

module_param(miimon, int, 0);

MODULE_PARM_DESC(miimon, "Link check interval in milliseconds");

module_param(updelay, int, 0);
@@ -242,14 +245,13 @@ static int bond_add_vlan(struct bonding *bond, unsigned short vlan_id) 
	dprintk("bond: %s, vlan id %d\n",

		(bond ? bond->dev->name: "None"), vlan_id);



	vlan = kmalloc(sizeof(struct vlan_entry), GFP_KERNEL);

	vlan = kzalloc(sizeof(struct vlan_entry), GFP_KERNEL);

	if (!vlan) {

		return -ENOMEM;

	}



	INIT_LIST_HEAD(&vlan->vlan_list);

	vlan->vlan_id = vlan_id;

	vlan->vlan_ip = 0;



	write_lock_bh(&bond->lock);
@@ -1208,6 +1210,9 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active) 
			bond->send_grat_arp = bond->params.num_grat_arp;

			bond_send_gratuitous_arp(bond);



			bond->send_unsol_na = bond->params.num_unsol_na;

			bond_send_unsolicited_na(bond);



			write_unlock_bh(&bond->curr_slave_lock);

			read_unlock(&bond->lock);
@@ -2463,6 +2468,12 @@ void bond_mii_monitor(struct work_struct *work) 
		read_unlock(&bond->curr_slave_lock);

	}



	if (bond->send_unsol_na) {

		read_lock(&bond->curr_slave_lock);

		bond_send_unsolicited_na(bond);

		read_unlock(&bond->curr_slave_lock);

	}



	if (bond_miimon_inspect(bond)) {

		read_unlock(&bond->lock);

		rtnl_lock();
@@ -3158,6 +3169,12 @@ void bond_activebackup_arp_mon(struct work_struct *work) 
		read_unlock(&bond->curr_slave_lock);

	}



	if (bond->send_unsol_na) {

		read_lock(&bond->curr_slave_lock);

		bond_send_unsolicited_na(bond);

		read_unlock(&bond->curr_slave_lock);

	}



	if (bond_ab_arp_inspect(bond, delta_in_ticks)) {

		read_unlock(&bond->lock);

		rtnl_lock();
@@ -3827,6 +3844,7 @@ static int bond_close(struct net_device *bond_dev) 
	write_lock_bh(&bond->lock);



	bond->send_grat_arp = 0;

	bond->send_unsol_na = 0;



	/* signal timers not to re-arm */

	bond->kill_timers = 1;
@@ -4542,6 +4560,7 @@ static int bond_init(struct net_device *bond_dev, struct bond_params *params) 
	bond->primary_slave = NULL;

	bond->dev = bond_dev;

	bond->send_grat_arp = 0;

	bond->send_unsol_na = 0;

	bond->setup_by_slave = 0;

	INIT_LIST_HEAD(&bond->vlan_list);
@@ -4791,6 +4810,13 @@ static int bond_check_params(struct bond_params *params) 
		num_grat_arp = 1;

	}



	if (num_unsol_na < 0 || num_unsol_na > 255) {

		printk(KERN_WARNING DRV_NAME

		       ": Warning: num_unsol_na (%d) not in range 0-255 so it "

		       "was reset to 1 \n", num_unsol_na);

		num_unsol_na = 1;

	}



	/* reset values for 802.3ad */

	if (bond_mode == BOND_MODE_8023AD) {

		if (!miimon) {
@@ -4992,6 +5018,7 @@ static int bond_check_params(struct bond_params *params) 
	params->xmit_policy = xmit_hashtype;

	params->miimon = miimon;

	params->num_grat_arp = num_grat_arp;

	params->num_unsol_na = num_unsol_na;

	params->arp_interval = arp_interval;

	params->arp_validate = arp_validate_value;

	params->updelay = updelay;
@@ -5144,6 +5171,7 @@ static int __init bonding_init(void) 


	register_netdevice_notifier(&bond_netdev_notifier);

	register_inetaddr_notifier(&bond_inetaddr_notifier);

	bond_register_ipv6_notifier();



	goto out;

err:
@@ -5166,6 +5194,7 @@ static void __exit bonding_exit(void) 
{

	unregister_netdevice_notifier(&bond_netdev_notifier);

	unregister_inetaddr_notifier(&bond_inetaddr_notifier);

	bond_unregister_ipv6_notifier();



	bond_destroy_sysfs();

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