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: Brian Haley <brian.haley@hp.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 32 insertions, 2 deletions

diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index ffb668dd6d3b..0491c7c2645b 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -19,16 +19,19 @@
 #include <linux/proc_fs.h>
 #include <linux/if_bonding.h>
 #include <linux/kobject.h>
+#include <linux/in6.h>
 #include "bond_3ad.h"
 #include "bond_alb.h"
 
-#define DRV_VERSION     "3.3.0"
-#define DRV_RELDATE     "June 10, 2008"
+#define DRV_VERSION     "3.4.0"
+#define DRV_RELDATE     "October 7, 2008"
 #define DRV_NAME        "bonding"
 #define DRV_DESCRIPTION "Ethernet Channel Bonding Driver"
 
 #define BOND_MAX_ARP_TARGETS    16
 
+extern struct list_head bond_dev_list;
+
 #ifdef BONDING_DEBUG
 #define dprintk(fmt, args...) \
         printk(KERN_DEBUG     \
@@ -126,6 +129,7 @@ struct bond_params {
         int xmit_policy;
         int miimon;
         int num_grat_arp;
+        int num_unsol_na;
         int arp_interval;
         int arp_validate;
         int use_carrier;
@@ -148,6 +152,9 @@ struct vlan_entry {
         struct list_head vlan_list;
         __be32 vlan_ip;
         unsigned short vlan_id;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        struct in6_addr vlan_ipv6;
+#endif
 };
 
 struct slave {
@@ -195,6 +202,7 @@ struct bonding {
         rwlock_t curr_slave_lock;
         s8       kill_timers;
         s8       send_grat_arp;
+        s8       send_unsol_na;
         s8       setup_by_slave;
         struct   net_device_stats stats;
 #ifdef CONFIG_PROC_FS
@@ -218,6 +226,9 @@ struct bonding {
         struct   delayed_work arp_work;
         struct   delayed_work alb_work;
         struct   delayed_work ad_work;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        struct   in6_addr master_ipv6;
+#endif
 };
 
 /**
@@ -341,5 +352,24 @@ extern struct bond_parm_tbl xmit_hashtype_tbl[];
 extern struct bond_parm_tbl arp_validate_tbl[];
 extern struct bond_parm_tbl fail_over_mac_tbl[];
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+void bond_send_unsolicited_na(struct bonding *bond);
+void bond_register_ipv6_notifier(void);
+void bond_unregister_ipv6_notifier(void);
+#else
+static inline void bond_send_unsolicited_na(struct bonding *bond)
+{
+        return;
+}
+static inline void bond_register_ipv6_notifier(void)
+{
+        return;
+}
+static inline void bond_unregister_ipv6_notifier(void)
+{
+        return;
+}
+#endif
+
 #endif /* _LINUX_BONDING_H */