[PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[David Ahern]

Currently, all ipv6 addresses are flushed when the interface is configured
down, even static address:

[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. The new setting defaults to
flush all addresses to maintain backwards compatibility. When the setting is
reset static addresses are not flushed:

[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

v2:
- only keep static addresses as suggested by Hannes
- added new managed flag to track configured addresses
- on ifdown do not remove from configured address from inet6_addr_lst
- on ifdown reset the TENTATIVE flag and set state to DAD so that DAD is
  redone when link is brought up again

Suggested-by: Hannes Frederic Sowa <hannes@redhat.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Hannes Frederic Sowa <hannes@redhat.com>

Signed-off-by: David Ahern <dsahern@gmail.com>
---
 include/linux/ipv6.h      |  1 +
 include/net/if_inet6.h    |  1 +
 include/uapi/linux/ipv6.h |  1 +
 net/ipv6/addrconf.c       | 55 ++++++++++++++++++++++++++++++++++++++---------
 4 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index 2805062c013f..b91b7c8be023 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -53,6 +53,7 @@ struct ipv6_devconf {
 	__s32           ndisc_notify;
 	__s32		suppress_frag_ndisc;
 	__s32		accept_ra_mtu;
+	__s32		flush_addr_on_down;
 	void		*sysctl;
 };
 
diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
index 98e5f9578f86..3b6323111f77 100644
--- a/include/net/if_inet6.h
+++ b/include/net/if_inet6.h
@@ -72,6 +72,7 @@ struct inet6_ifaddr {
 	int			regen_count;
 
 	bool			tokenized;
+	bool			managed;
 
 	struct rcu_head		rcu;
 	struct in6_addr		peer_addr;
diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
index 437a6a4b125a..ed10d4ba8340 100644
--- a/include/uapi/linux/ipv6.h
+++ b/include/uapi/linux/ipv6.h
@@ -170,6 +170,7 @@ enum {
 	DEVCONF_ACCEPT_RA_FROM_LOCAL,
 	DEVCONF_USE_OPTIMISTIC,
 	DEVCONF_ACCEPT_RA_MTU,
+	DEVCONF_FLUSH_ON_DOWN,
 	DEVCONF_MAX
 };
 
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 7dcc065e2160..e0e82aad2116 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -202,6 +202,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
 	.accept_dad		= 1,
 	.suppress_frag_ndisc	= 1,
 	.accept_ra_mtu		= 1,
+	.flush_addr_on_down	= 1,
 };
 
 static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
@@ -240,6 +241,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
 	.accept_dad		= 1,
 	.suppress_frag_ndisc	= 1,
 	.accept_ra_mtu		= 1,
+	.flush_addr_on_down	= 1,
 };
 
 /* Check if a valid qdisc is available */
@@ -870,6 +872,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
 	ifa->prefered_lft = prefered_lft;
 	ifa->cstamp = ifa->tstamp = jiffies;
 	ifa->tokenized = false;
+	ifa->managed = false;
 
 	ifa->rt = rt;
 
@@ -2510,6 +2513,8 @@ static int inet6_addr_add(struct net *net, int ifindex,
 			    valid_lft, prefered_lft);
 
 	if (!IS_ERR(ifp)) {
+		ifp->managed = true;
+
 		if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
 			addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
 					      expires, flags);
@@ -3032,8 +3037,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 {
 	struct net *net = dev_net(dev);
 	struct inet6_dev *idev;
-	struct inet6_ifaddr *ifa;
+	struct inet6_ifaddr *ifa, *tmp;
 	int state, i;
+	struct list_head del_list;
 
 	ASSERT_RTNL();
 
@@ -3067,9 +3073,12 @@ static int addrconf_ifdown(struct net_device *dev, int how)
 restart:
 		hlist_for_each_entry_rcu(ifa, h, addr_lst) {
 			if (ifa->idev == idev) {
-				hlist_del_init_rcu(&ifa->addr_lst);
 				addrconf_del_dad_work(ifa);
-				goto restart;
+				if (how || idev->cnf.flush_addr_on_down ||
+				    !ifa->managed) {
+					hlist_del_init_rcu(&ifa->addr_lst);
+					goto restart;
+				}
 			}
 		}
 		spin_unlock_bh(&addrconf_hash_lock);
@@ -3103,14 +3112,35 @@ restart:
 		write_lock_bh(&idev->lock);
 	}
 
-	while (!list_empty(&idev->addr_list)) {
-		ifa = list_first_entry(&idev->addr_list,
+	INIT_LIST_HEAD(&del_list);
+	list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
+		/* 
+		 * on NETDEV_DOWN events do not flush managed (user configured)
+		 * addresses unless configured to do so. If the address is not
+		 * deleted reset flags and state such that DAD is re-done on a
+ 		 * subsequent link up.
+ 		 */
+		if (!how && !idev->cnf.flush_addr_on_down && ifa->managed) {
+	    		if (!(ifa->flags & IFA_F_NODAD)) {
+				ifa->flags |= IFA_F_TENTATIVE;
+				ifa->state = INET6_IFADDR_STATE_DAD;
+			}
+		} else {
+			list_del(&ifa->if_list);
+			list_add(&ifa->if_list, &del_list);
+		}
+	}
+
+	write_unlock_bh(&idev->lock);
+
+	while (!list_empty(&del_list)) {
+		ifa = list_first_entry(&del_list,
 				       struct inet6_ifaddr, if_list);
+
 		addrconf_del_dad_work(ifa);
 
 		list_del(&ifa->if_list);
 
-		write_unlock_bh(&idev->lock);
 
 		spin_lock_bh(&ifa->state_lock);
 		state = ifa->state;
@@ -3122,12 +3152,8 @@ restart:
 			inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
 		}
 		in6_ifa_put(ifa);
-
-		write_lock_bh(&idev->lock);
 	}
 
-	write_unlock_bh(&idev->lock);
-
 	/* Step 5: Discard anycast and multicast list */
 	if (how) {
 		ipv6_ac_destroy_dev(idev);
@@ -4383,6 +4409,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
 	array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
 	array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
 	array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu;
+	array[DEVCONF_FLUSH_ON_DOWN] = cnf->flush_addr_on_down;
 }
 
 static inline size_t inet6_ifla6_size(void)
@@ -5269,6 +5296,14 @@ 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

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[David Miller]

From: David Ahern <dsahern@gmail.com>
Date: Wed, 28 Jan 2015 21:01:05 -0700

> @@ -3032,8 +3037,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
>  {
>  	struct net *net = dev_net(dev);
>  	struct inet6_dev *idev;
> -	struct inet6_ifaddr *ifa;
> +	struct inet6_ifaddr *ifa, *tmp;
>  	int state, i;
> +	struct list_head del_list;

Please order local variable declarations from longest to shortest line
(ie. reverse christmas tree) when it is easy to do so.

> +		/* 
> +		 * on NETDEV_DOWN events do not flush managed (user configured)
> +		 * addresses unless configured to do so. If the address is not
> +		 * deleted reset flags and state such that DAD is re-done on a
> + 		 * subsequent link up.
> + 		 */

Comments in the networking are to be formatted:

	/* Like
	 * this.
	 */

Thanks.

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[David Ahern]

Hi Hannes:

Any comments before I spin a v3 to address Dave's comments?

David

On 1/28/15 9:01 PM, David Ahern wrote:
> Currently, all ipv6 addresses are flushed when the interface is configured
> down, even static address:
>
> [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. The new setting defaults to
> flush all addresses to maintain backwards compatibility. When the setting is
> reset static addresses are not flushed:
>
> [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
>
> v2:
> - only keep static addresses as suggested by Hannes
> - added new managed flag to track configured addresses
> - on ifdown do not remove from configured address from inet6_addr_lst
> - on ifdown reset the TENTATIVE flag and set state to DAD so that DAD is
>    redone when link is brought up again
>
> Suggested-by: Hannes Frederic Sowa <hannes@redhat.com>
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Hannes Frederic Sowa <hannes@redhat.com>
>
> Signed-off-by: David Ahern <dsahern@gmail.com>
> ---
>   include/linux/ipv6.h      |  1 +
>   include/net/if_inet6.h    |  1 +
>   include/uapi/linux/ipv6.h |  1 +
>   net/ipv6/addrconf.c       | 55 ++++++++++++++++++++++++++++++++++++++---------
>   4 files changed, 48 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
> index 2805062c013f..b91b7c8be023 100644
> --- a/include/linux/ipv6.h
> +++ b/include/linux/ipv6.h
> @@ -53,6 +53,7 @@ struct ipv6_devconf {
>   	__s32           ndisc_notify;
>   	__s32		suppress_frag_ndisc;
>   	__s32		accept_ra_mtu;
> +	__s32		flush_addr_on_down;
>   	void		*sysctl;
>   };
>
> diff --git a/include/net/if_inet6.h b/include/net/if_inet6.h
> index 98e5f9578f86..3b6323111f77 100644
> --- a/include/net/if_inet6.h
> +++ b/include/net/if_inet6.h
> @@ -72,6 +72,7 @@ struct inet6_ifaddr {
>   	int			regen_count;
>
>   	bool			tokenized;
> +	bool			managed;
>
>   	struct rcu_head		rcu;
>   	struct in6_addr		peer_addr;
> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
> index 437a6a4b125a..ed10d4ba8340 100644
> --- a/include/uapi/linux/ipv6.h
> +++ b/include/uapi/linux/ipv6.h
> @@ -170,6 +170,7 @@ enum {
>   	DEVCONF_ACCEPT_RA_FROM_LOCAL,
>   	DEVCONF_USE_OPTIMISTIC,
>   	DEVCONF_ACCEPT_RA_MTU,
> +	DEVCONF_FLUSH_ON_DOWN,
>   	DEVCONF_MAX
>   };
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 7dcc065e2160..e0e82aad2116 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -202,6 +202,7 @@ static struct ipv6_devconf ipv6_devconf __read_mostly = {
>   	.accept_dad		= 1,
>   	.suppress_frag_ndisc	= 1,
>   	.accept_ra_mtu		= 1,
> +	.flush_addr_on_down	= 1,
>   };
>
>   static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
> @@ -240,6 +241,7 @@ static struct ipv6_devconf ipv6_devconf_dflt __read_mostly = {
>   	.accept_dad		= 1,
>   	.suppress_frag_ndisc	= 1,
>   	.accept_ra_mtu		= 1,
> +	.flush_addr_on_down	= 1,
>   };
>
>   /* Check if a valid qdisc is available */
> @@ -870,6 +872,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr,
>   	ifa->prefered_lft = prefered_lft;
>   	ifa->cstamp = ifa->tstamp = jiffies;
>   	ifa->tokenized = false;
> +	ifa->managed = false;
>
>   	ifa->rt = rt;
>
> @@ -2510,6 +2513,8 @@ static int inet6_addr_add(struct net *net, int ifindex,
>   			    valid_lft, prefered_lft);
>
>   	if (!IS_ERR(ifp)) {
> +		ifp->managed = true;
> +
>   		if (!(ifa_flags & IFA_F_NOPREFIXROUTE)) {
>   			addrconf_prefix_route(&ifp->addr, ifp->prefix_len, dev,
>   					      expires, flags);
> @@ -3032,8 +3037,9 @@ static int addrconf_ifdown(struct net_device *dev, int how)
>   {
>   	struct net *net = dev_net(dev);
>   	struct inet6_dev *idev;
> -	struct inet6_ifaddr *ifa;
> +	struct inet6_ifaddr *ifa, *tmp;
>   	int state, i;
> +	struct list_head del_list;
>
>   	ASSERT_RTNL();
>
> @@ -3067,9 +3073,12 @@ static int addrconf_ifdown(struct net_device *dev, int how)
>   restart:
>   		hlist_for_each_entry_rcu(ifa, h, addr_lst) {
>   			if (ifa->idev == idev) {
> -				hlist_del_init_rcu(&ifa->addr_lst);
>   				addrconf_del_dad_work(ifa);
> -				goto restart;
> +				if (how || idev->cnf.flush_addr_on_down ||
> +				    !ifa->managed) {
> +					hlist_del_init_rcu(&ifa->addr_lst);
> +					goto restart;
> +				}
>   			}
>   		}
>   		spin_unlock_bh(&addrconf_hash_lock);
> @@ -3103,14 +3112,35 @@ restart:
>   		write_lock_bh(&idev->lock);
>   	}
>
> -	while (!list_empty(&idev->addr_list)) {
> -		ifa = list_first_entry(&idev->addr_list,
> +	INIT_LIST_HEAD(&del_list);
> +	list_for_each_entry_safe(ifa, tmp, &idev->addr_list, if_list) {
> +		/*
> +		 * on NETDEV_DOWN events do not flush managed (user configured)
> +		 * addresses unless configured to do so. If the address is not
> +		 * deleted reset flags and state such that DAD is re-done on a
> + 		 * subsequent link up.
> + 		 */
> +		if (!how && !idev->cnf.flush_addr_on_down && ifa->managed) {
> +	    		if (!(ifa->flags & IFA_F_NODAD)) {
> +				ifa->flags |= IFA_F_TENTATIVE;
> +				ifa->state = INET6_IFADDR_STATE_DAD;
> +			}
> +		} else {
> +			list_del(&ifa->if_list);
> +			list_add(&ifa->if_list, &del_list);
> +		}
> +	}
> +
> +	write_unlock_bh(&idev->lock);
> +
> +	while (!list_empty(&del_list)) {
> +		ifa = list_first_entry(&del_list,
>   				       struct inet6_ifaddr, if_list);
> +
>   		addrconf_del_dad_work(ifa);
>
>   		list_del(&ifa->if_list);
>
> -		write_unlock_bh(&idev->lock);
>
>   		spin_lock_bh(&ifa->state_lock);
>   		state = ifa->state;
> @@ -3122,12 +3152,8 @@ restart:
>   			inet6addr_notifier_call_chain(NETDEV_DOWN, ifa);
>   		}
>   		in6_ifa_put(ifa);
> -
> -		write_lock_bh(&idev->lock);
>   	}
>
> -	write_unlock_bh(&idev->lock);
> -
>   	/* Step 5: Discard anycast and multicast list */
>   	if (how) {
>   		ipv6_ac_destroy_dev(idev);
> @@ -4383,6 +4409,7 @@ static inline void ipv6_store_devconf(struct ipv6_devconf *cnf,
>   	array[DEVCONF_SUPPRESS_FRAG_NDISC] = cnf->suppress_frag_ndisc;
>   	array[DEVCONF_ACCEPT_RA_FROM_LOCAL] = cnf->accept_ra_from_local;
>   	array[DEVCONF_ACCEPT_RA_MTU] = cnf->accept_ra_mtu;
> +	array[DEVCONF_FLUSH_ON_DOWN] = cnf->flush_addr_on_down;
>   }
>
>   static inline size_t inet6_ifla6_size(void)
> @@ -5269,6 +5296,14 @@ 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 */
>   		}
>   	},
>

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[Brian Haley]

On 01/28/2015 11:01 PM, David Ahern wrote:
> Currently, all ipv6 addresses are flushed when the interface is configured
> down, even static address:
> 
...
> diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
> index 2805062c013f..b91b7c8be023 100644
> --- a/include/linux/ipv6.h
> +++ b/include/linux/ipv6.h
> @@ -53,6 +53,7 @@ struct ipv6_devconf {
>  	__s32           ndisc_notify;
>  	__s32		suppress_frag_ndisc;
>  	__s32		accept_ra_mtu;
> +	__s32		flush_addr_on_down;
>  	void		*sysctl;
>  };
...
> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
> index 437a6a4b125a..ed10d4ba8340 100644
> --- a/include/uapi/linux/ipv6.h
> +++ b/include/uapi/linux/ipv6.h
> @@ -170,6 +170,7 @@ enum {
>  	DEVCONF_ACCEPT_RA_FROM_LOCAL,
>  	DEVCONF_USE_OPTIMISTIC,
>  	DEVCONF_ACCEPT_RA_MTU,
> +	DEVCONF_FLUSH_ON_DOWN,

nit: DEVCONF_FLUSH_ADDR_ON_DOWN to match the name added to ipv6_devconf.

-Brian

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[Stephen Hemminger]

On Wed, 28 Jan 2015 21:01:05 -0700
David Ahern <dsahern@gmail.com> wrote:

> Currently, all ipv6 addresses are flushed when the interface is configured
> down, even static address:
> 
> [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. The new setting defaults to
> flush all addresses to maintain backwards compatibility. When the setting is
> reset static addresses are not flushed:
> 
> [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
> 
> v2:
> - only keep static addresses as suggested by Hannes
> - added new managed flag to track configured addresses
> - on ifdown do not remove from configured address from inet6_addr_lst
> - on ifdown reset the TENTATIVE flag and set state to DAD so that DAD is
>   redone when link is brought up again
> 
> Suggested-by: Hannes Frederic Sowa <hannes@redhat.com>
> Signed-off-by: David Ahern <dsahern@gmail.com>
> Cc: Hannes Frederic Sowa <hannes@redhat.com>
> 
> Signed-off-by: David Ahern <dsahern@gmail.com>

Checkpatch complains about space before tab, which could be your
mailer mangling the patch.

This should probably go into the netconf netlink message as well.

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[David Ahern]

On 2/2/15 4:10 PM, Stephen Hemminger wrote:
> Checkpatch complains about space before tab, which could be your
> mailer mangling the patch.

Yes, found that a couple of days ago. I use 'git send-email' to send the 
patches, and I have a pre-commit hook to run checkpatch.pl. Perhaps I 
goofed something in the recent latptop transitions.

>
> This should probably go into the netconf netlink message as well.
>

Not sure I understand this point. Can you point me to a code reference 
to look up?

Though that did remind me that I should add a blurb in 
Documentation/networking/ip-sysctl.txt.

David

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[Stephen Hemminger]

On Mon, 02 Feb 2015 17:11:56 -0700
David Ahern <dsahern@gmail.com> wrote:

> On 2/2/15 4:10 PM, Stephen Hemminger wrote:
> > Checkpatch complains about space before tab, which could be your
> > mailer mangling the patch.
> 
> Yes, found that a couple of days ago. I use 'git send-email' to send the 
> patches, and I have a pre-commit hook to run checkpatch.pl. Perhaps I 
> goofed something in the recent latptop transitions.
> 
> >
> > This should probably go into the netconf netlink message as well.
> >
> 
> Not sure I understand this point. Can you point me to a code reference 
> to look up?

Look at how forwarding flag is propagated already via NETCONFA_FORWARDING.

Re: [PATCH] net: ipv6: Make address flushing on ifdown optional - v2

[Stephen Hemminger]

On Mon, 02 Feb 2015 17:11:56 -0700
David Ahern <dsahern@gmail.com> wrote:

> On 2/2/15 4:10 PM, Stephen Hemminger wrote:
> > Checkpatch complains about space before tab, which could be your
> > mailer mangling the patch.
> 
> Yes, found that a couple of days ago. I use 'git send-email' to send the 
> patches, and I have a pre-commit hook to run checkpatch.pl. Perhaps I 
> goofed something in the recent latptop transitions.
> 
> >
> > This should probably go into the netconf netlink message as well.
> >
> 
> Not sure I understand this point. Can you point me to a code reference 
> to look up?
> 
> Though that did remind me that I should add a blurb in 
> Documentation/networking/ip-sysctl.txt.
> 
> David

Never mind, actually NETCONFA stuff is mostly for case where
listener needs to know how to handle offload, and this  doesn't
impact that.