[Xen-devel] [PATCH] net: add ARP notify option for devices

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

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"),



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel