From: Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>
This adds another inet device option to enable gratuitous ARP
when device is brought up or address change. This is handy for
clusters or virtualization.
Signed-off-by: Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
Documentation/networking/ip-sysctl.txt | 6 ++++++
include/linux/inetdevice.h | 1 +
include/linux/sysctl.h | 1 +
kernel/sysctl_check.c | 1 +
net/ipv4/devinet.c | 9 +++++++++
5 files changed, 18 insertions(+)
===================================================================
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -782,6 +782,12 @@
 The max value from conf/{all,interface}/arp_ignore is used
 when ARP request is received on the {interface}
+arp_notify - BOOLEAN
+ Define mode for notification of address and device changes.
+ 0 - (default): do nothing
+ 1 - Generate gratuitous arp replies when device is brought up
+ or hardware address changes.
+
arp_accept - BOOLEAN
 Define behavior when gratuitous arp replies are received:
 0 - drop gratuitous arp frames
===================================================================
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -108,6 +108,7 @@
#define IN_DEV_ARPFILTER(in_dev) IN_DEV_ORCONF((in_dev), ARPFILTER)
#define IN_DEV_ARP_ANNOUNCE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_ANNOUNCE)
#define IN_DEV_ARP_IGNORE(in_dev) IN_DEV_MAXCONF((in_dev), ARP_IGNORE)
+#define IN_DEV_ARP_NOTIFY(in_dev) IN_DEV_MAXCONF((in_dev), ARP_NOTIFY)
struct in_ifaddr
{
===================================================================
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -490,6 +490,7 @@
 NET_IPV4_CONF_ARP_IGNORE=19,
 NET_IPV4_CONF_PROMOTE_SECONDARIES=20,
 NET_IPV4_CONF_ARP_ACCEPT=21,
+ NET_IPV4_CONF_ARP_NOTIFY=22,
 __NET_IPV4_CONF_MAX
};
===================================================================
--- a/kernel/sysctl_check.c
+++ b/kernel/sysctl_check.c
@@ -219,6 +219,7 @@
 { NET_IPV4_CONF_ARP_IGNORE, "arp_ignore" },
 { NET_IPV4_CONF_PROMOTE_SECONDARIES, "promote_secondaries" },
 { NET_IPV4_CONF_ARP_ACCEPT, "arp_accept" },
+ { NET_IPV4_CONF_ARP_NOTIFY, "arp_notify" },
 {}
};
===================================================================
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1075,6 +1075,14 @@
 }
 }
 ip_mc_up(in_dev);
+ /* fall through */
+ case NETDEV_CHANGEADDR:
+ if (IN_DEV_ARP_NOTIFY(in_dev))
+ arp_send(ARPOP_REQUEST, ETH_P_ARP,
+ in_dev->ifa_list->ifa_address,
+ dev,
+ in_dev->ifa_list->ifa_address,
+ NULL, dev->dev_addr, NULL);
 break;
 case NETDEV_DOWN:
 ip_mc_down(in_dev);
@@ -1439,6 +1447,7 @@
 DEVINET_SYSCTL_RW_ENTRY(ARP_ANNOUNCE, "arp_announce"),
 DEVINET_SYSCTL_RW_ENTRY(ARP_IGNORE, "arp_ignore"),
 DEVINET_SYSCTL_RW_ENTRY(ARP_ACCEPT, "arp_accept"),
+ DEVINET_SYSCTL_RW_ENTRY(ARP_NOTIFY, "arp_notify"),
 DEVINET_SYSCTL_FLUSHING_ENTRY(NOXFRM, "disable_xfrm"),
 DEVINET_SYSCTL_FLUSHING_ENTRY(NOPOLICY, "disable_policy"),
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