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Message-Id: <1421263039-96198-1-git-send-email-dsahern@gmail.com>
Date: Wed, 14 Jan 2015 12:17:19 -0700
From: David Ahern <dsahern@...il.com>
To: netdev@...r.kernel.org
Cc: hannes@...hat.com, David Ahern <dsahern@...il.com>
Subject: [RFC PATCH] net: ipv6: Make address flushing on ifdown optional
Currently, ipv6 addresses are flushed when the interface is configured down:
[root@f20 ~]# ip -6 addr add dev eth1 2000:11:1:1::1/64
[root@f20 ~]# ip addr show dev eth1
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff
inet6 2000:11:1:1::1/64 scope global tentative
valid_lft forever preferred_lft forever
[root@f20 ~]# ip link set dev eth1 up
[root@f20 ~]# ip link set dev eth1 down
[root@f20 ~]# ip addr show dev eth1
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff
Add a new sysctl to make this behavior optional. Setting defaults to flush
addresses to maintain backwards compatibility. When reset flushing is bypassed:
[root@f20 ~]# echo 0 > /proc/sys/net/ipv6/conf/eth1/flush_addr_on_down
[root@f20 ~]# ip -6 addr add dev eth1 2000:11:1:1::1/64
[root@f20 ~]# ip addr show dev eth1
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff
inet6 2000:11:1:1::1/64 scope global tentative
valid_lft forever preferred_lft forever
[root@f20 ~]# ip link set dev eth1 up
[root@f20 ~]# ip link set dev eth1 down
[root@f20 ~]# ip addr show dev eth1
3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast state DOWN group default qlen 1000
link/ether 02:04:11:22:33:01 brd ff:ff:ff:ff:ff:ff
inet6 2000:11:1:1::1/64 scope global
valid_lft forever preferred_lft forever
inet6 fe80::4:11ff:fe22:3301/64 scope link
valid_lft forever preferred_lft forever
Suggested-by: Hannes Frederic Sowa <hannes@...hat.com>
Signed-off-by: David Ahern <dsahern@...il.com>
Cc: Hannes Frederic Sowa <hannes@...hat.com>
---
include/linux/ipv6.h | 1 +
include/uapi/linux/ipv6.h | 1 +
net/ipv6/addrconf.c | 15 +++++++++++++++
3 files changed, 17 insertions(+)
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c694e7baa621..1d726e39f09f 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -52,6 +52,7 @@ struct ipv6_devconf {
__s32 force_tllao;
__s32 ndisc_notify;
__s32 suppress_frag_ndisc;
+ __s32 flush_addr_on_down;
void *sysctl;
};
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index e863d088b9a5..c7cb79e0f0fe 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -165,6 +165,7 @@ enum {
DEVCONF_SUPPRESS_FRAG_NDISC,
DEVCONF_ACCEPT_RA_FROM_LOCAL,
DEVCONF_USE_OPTIMISTIC,
+ DEVCONF_FLUSH_ON_DOWN,
DEVCONF_MAX
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index f7c8bbeb27b7..5c0d49073cb1 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -201,6 +201,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
.disable_ipv6 = 0,
.accept_dad = 1,
.suppress_frag_ndisc = 1,
+ .flush_addr_on_down = 1,
};
static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -238,6 +239,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
.disable_ipv6 = 0,
.accept_dad = 1,
.suppress_frag_ndisc = 1,
+ .flush_addr_on_down = 1,
};
/* Check if a valid qdisc is available */
@@ -3083,6 +3085,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
if (how && del_timer(&idev->regen_timer))
in6_dev_put(idev);
+ if (!how && !idev->cnf.flush_addr_on_down)
+ goto unlock;
+
/* Step 3: clear tempaddr list */
while (!list_empty(&idev->tempaddr_list)) {
ifa = list_first_entry(&idev->tempaddr_list,
@@ -3123,6 +3128,7 @@ static int addrconf_ifdown(struct net_device *dev, int how)
write_lock_bh(&idev->lock);
}
+unlock:
write_unlock_bh(&idev->lock);
/* Step 5: Discard anycast and multicast list */
@@ -4376,6 +4382,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
array[DEVCONF_NDISC_NOTIFY] = cnf->ndisc_notify;
array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
+ array[DEVCONF_FLUSH_ON_DOWN] = cnf->flush_addr_on_down;
}
static inline size_t inet6_ifla6_size(void)
@@ -5253,6 +5260,14 @@ static struct addrconf_sysctl_table
.proc_handler = proc_dointvec,
},
{
+ .procname = "flush_addr_on_down",
+ .data = &ipv6_devconf.flush_addr_on_down,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec,
+
+ },
+ {
/* sentinel */
}
},
--
1.9.3 (Apple Git-50)
--
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