[IPV4]: Primary and secondary addresses
Add an option to make secondary IP addresses get promoted
when primary IP addresses are removed from the device.
It defaults to off to preserve existing behavior.
Signed-off-by: Harald Welte <laforge@gnumonks.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 6fafb27..7e1e15f 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -29,6 +29,7 @@
int no_xfrm;
int no_policy;
int force_igmp_version;
+ int promote_secondaries;
void *sysctl;
};
@@ -71,6 +72,7 @@
#define IN_DEV_SEC_REDIRECTS(in_dev) (ipv4_devconf.secure_redirects || (in_dev)->cnf.secure_redirects)
#define IN_DEV_IDTAG(in_dev) ((in_dev)->cnf.tag)
#define IN_DEV_MEDIUM_ID(in_dev) ((in_dev)->cnf.medium_id)
+#define IN_DEV_PROMOTE_SECONDARIES(in_dev) (ipv4_devconf.promote_secondaries || (in_dev)->cnf.promote_secondaries)
#define IN_DEV_RX_REDIRECTS(in_dev) \
((IN_DEV_FORWARD(in_dev) && \
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index 7729981..23032d9 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -399,6 +399,7 @@
NET_IPV4_CONF_FORCE_IGMP_VERSION=17,
NET_IPV4_CONF_ARP_ANNOUNCE=18,
NET_IPV4_CONF_ARP_IGNORE=19,
+ NET_IPV4_CONF_PROMOTE_SECONDARIES=20,
__NET_IPV4_CONF_MAX
};
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 3cc9673..478a301 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -233,11 +233,14 @@
static void inet_del_ifa(struct in_device *in_dev, struct in_ifaddr **ifap,
int destroy)
{
+ struct in_ifaddr *promote = NULL;
struct in_ifaddr *ifa1 = *ifap;
ASSERT_RTNL();
- /* 1. Deleting primary ifaddr forces deletion all secondaries */
+ /* 1. Deleting primary ifaddr forces deletion all secondaries
+ * unless alias promotion is set
+ **/
if (!(ifa1->ifa_flags & IFA_F_SECONDARY)) {
struct in_ifaddr *ifa;
@@ -251,11 +254,16 @@
continue;
}
- *ifap1 = ifa->ifa_next;
+ if (!IN_DEV_PROMOTE_SECONDARIES(in_dev)) {
+ *ifap1 = ifa->ifa_next;
- rtmsg_ifa(RTM_DELADDR, ifa);
- notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa);
- inet_free_ifa(ifa);
+ rtmsg_ifa(RTM_DELADDR, ifa);
+ notifier_call_chain(&inetaddr_chain, NETDEV_DOWN, ifa);
+ inet_free_ifa(ifa);
+ } else {
+ promote = ifa;
+ break;
+ }
}
}
@@ -281,6 +289,13 @@
if (!in_dev->ifa_list)
inetdev_destroy(in_dev);
}
+
+ if (promote && IN_DEV_PROMOTE_SECONDARIES(in_dev)) {
+ /* not sure if we should send a delete notify first? */
+ promote->ifa_flags &= ~IFA_F_SECONDARY;
+ rtmsg_ifa(RTM_NEWADDR, promote);
+ notifier_call_chain(&inetaddr_chain, NETDEV_UP, promote);
+ }
}
static int inet_insert_ifa(struct in_ifaddr *ifa)
@@ -1384,6 +1399,15 @@
.proc_handler = &ipv4_doint_and_flush,
.strategy = &ipv4_doint_and_flush_strategy,
},
+ {
+ .ctl_name = NET_IPV4_CONF_PROMOTE_SECONDARIES,
+ .procname = "promote_secondaries",
+ .data = &ipv4_devconf.promote_secondaries,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = &ipv4_doint_and_flush,
+ .strategy = &ipv4_doint_and_flush_strategy,
+ },
},
.devinet_dev = {
{