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* [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace
@ 2014-04-06 19:04 Heiner Kallweit
  2014-04-06 20:27 ` Daniel Borkmann
  0 siblings, 1 reply; 3+ messages in thread
From: Heiner Kallweit @ 2014-04-06 19:04 UTC (permalink / raw)
  To: netdev

If the kernel takes care of global and temporary addresses it can happen that the global
address is deleted from userspace, e.g. by network managers in case the link goes (temporarily) down.
In addition to the then orphaned temporary address(es) the next RA will create a new temporary address.
Therefore we might end up with more than one non-deprecated temporary address for the same prefix
for a longer period of time (>regen_advance). According to RfC 4941 sect. 3.4 this should not happen.

Fix this by reparenting orphaned temporary addresses.

Signed-off-by: Heiner Kallweit <heiner.kallweit@web.de>
---
 net/ipv6/addrconf.c | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 6c7fa08..4d5595b 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -2077,14 +2077,34 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 {
 	u32 flags;
 	struct inet6_ifaddr *ift;
+	unsigned long regen_advance;
 
 	read_lock_bh(&idev->lock);
+	regen_advance = idev->cnf.regen_max_retry *
+			idev->cnf.dad_transmits *
+			NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ;
 	/* update all temporary addresses in the list */
 	list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
 		int age, max_valid, max_prefered;
+		bool reparent;
 
-		if (ifp != ift->ifpub)
-			continue;
+		reparent = false;
+		spin_lock(&ift->lock);
+		if (ifp != ift->ifpub) {
+			/* reparent if orphaned temporary address with same
+			 * prefix is found
+			 */
+			if (ipv6_prefix_equal(&ift->addr, &ifp->addr,
+					      ift->prefix_len)) {
+				in6_ifa_hold(ifp);
+				in6_ifa_put(ift->ifpub);
+				ift->ifpub = ifp;
+				reparent = true;
+			} else {
+				spin_unlock(&ift->lock);
+				continue;
+			}
+		}
 
 		/* RFC 4941 section 3.3:
 		 * If a received option will extend the lifetime of a public
@@ -2110,7 +2130,6 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 		if (prefered_lft > max_prefered)
 			prefered_lft = max_prefered;
 
-		spin_lock(&ift->lock);
 		flags = ift->flags;
 		ift->valid_lft = valid_lft;
 		ift->prefered_lft = prefered_lft;
@@ -2119,6 +2138,15 @@ static void manage_tempaddrs(struct inet6_dev *idev,
 			ift->flags &= ~IFA_F_DEPRECATED;
 
 		spin_unlock(&ift->lock);
+		/* Don't create a temporary address if we reparented one which
+		 * is prefered more than regen_advance
+		 */
+		if (reparent && prefered_lft > regen_advance) {
+			create = false;
+			pr_info("%s: reparent orphaned temporary address\n",
+				__func__);
+		}
+
 		if (!(flags&IFA_F_TENTATIVE))
 			ipv6_ifa_notify(0, ift);
 	}
-- 
1.9.1.315.g3f09db0.dirty

^ permalink raw reply related	[flat|nested] 3+ messages in thread
* Re: [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace
  2014-04-06 19:04 [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace Heiner Kallweit
@ 2014-04-06 20:27 ` Daniel Borkmann
  2014-04-07  5:18   ` Heiner Kallweit
  0 siblings, 1 reply; 3+ messages in thread
From: Daniel Borkmann @ 2014-04-06 20:27 UTC (permalink / raw)
  To: Heiner Kallweit; +Cc: netdev, Hannes Frederic Sowa

On 04/06/2014 09:04 PM, Heiner Kallweit wrote:
> If the kernel takes care of global and temporary addresses it can happen that the global
> address is deleted from userspace, e.g. by network managers in case the link goes (temporarily) down.
> In addition to the then orphaned temporary address(es) the next RA will create a new temporary address.
> Therefore we might end up with more than one non-deprecated temporary address for the same prefix
> for a longer period of time (>regen_advance). According to RfC 4941 sect. 3.4 this should not happen.

Nit: your commit description should only be ~75 chars wide max

> Fix this by reparenting orphaned temporary addresses.
>
> Signed-off-by: Heiner Kallweit <heiner.kallweit@web.de>
> ---
>   net/ipv6/addrconf.c | 34 +++++++++++++++++++++++++++++++---
>   1 file changed, 31 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
> index 6c7fa08..4d5595b 100644
> --- a/net/ipv6/addrconf.c
> +++ b/net/ipv6/addrconf.c
> @@ -2077,14 +2077,34 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>   {
>   	u32 flags;
>   	struct inet6_ifaddr *ift;
> +	unsigned long regen_advance;
>
>   	read_lock_bh(&idev->lock);
> +	regen_advance = idev->cnf.regen_max_retry *
> +			idev->cnf.dad_transmits *
> +			NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ;
>   	/* update all temporary addresses in the list */
>   	list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
>   		int age, max_valid, max_prefered;
> +		bool reparent;
>
> -		if (ifp != ift->ifpub)
> -			continue;
> +		reparent = false;

You can collapse initialization where you declare the variable.

> +		spin_lock(&ift->lock);
> +		if (ifp != ift->ifpub) {
> +			/* reparent if orphaned temporary address with same
> +			 * prefix is found
> +			 */
> +			if (ipv6_prefix_equal(&ift->addr, &ifp->addr,
> +					      ift->prefix_len)) {
> +				in6_ifa_hold(ifp);
> +				in6_ifa_put(ift->ifpub);
> +				ift->ifpub = ifp;
> +				reparent = true;
> +			} else {
> +				spin_unlock(&ift->lock);
> +				continue;
> +			}
> +		}
>
>   		/* RFC 4941 section 3.3:
>   		 * If a received option will extend the lifetime of a public
> @@ -2110,7 +2130,6 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>   		if (prefered_lft > max_prefered)
>   			prefered_lft = max_prefered;
>
> -		spin_lock(&ift->lock);
>   		flags = ift->flags;
>   		ift->valid_lft = valid_lft;
>   		ift->prefered_lft = prefered_lft;
> @@ -2119,6 +2138,15 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>   			ift->flags &= ~IFA_F_DEPRECATED;
>
>   		spin_unlock(&ift->lock);
> +		/* Don't create a temporary address if we reparented one which
> +		 * is prefered more than regen_advance

Nit: s/prefered/preferred/

> +		 */
> +		if (reparent && prefered_lft > regen_advance) {
> +			create = false;
> +			pr_info("%s: reparent orphaned temporary address\n",
> +				__func__);

The pr_info() should ideally be removed (or at least made pr_debug()).

> +		}
> +
>   		if (!(flags&IFA_F_TENTATIVE))
>   			ipv6_ifa_notify(0, ift);
>   	}
>

^ permalink raw reply	[flat|nested] 3+ messages in thread
* Re: [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace
  2014-04-06 20:27 ` Daniel Borkmann
@ 2014-04-07  5:18   ` Heiner Kallweit
  0 siblings, 0 replies; 3+ messages in thread
From: Heiner Kallweit @ 2014-04-07  5:18 UTC (permalink / raw)
  To: Daniel Borkmann; +Cc: netdev, Hannes Frederic Sowa

Am 06.04.2014 22:27, schrieb Daniel Borkmann:
> On 04/06/2014 09:04 PM, Heiner Kallweit wrote:
>> If the kernel takes care of global and temporary addresses it can happen that the global
>> address is deleted from userspace, e.g. by network managers in case the link goes (temporarily) down.
>> In addition to the then orphaned temporary address(es) the next RA will create a new temporary address.
>> Therefore we might end up with more than one non-deprecated temporary address for the same prefix
>> for a longer period of time (>regen_advance). According to RfC 4941 sect. 3.4 this should not happen.
>
> Nit: your commit description should only be ~75 chars wide max
>
>> Fix this by reparenting orphaned temporary addresses.
>>
>> Signed-off-by: Heiner Kallweit <heiner.kallweit@web.de>
>> ---
>>   net/ipv6/addrconf.c | 34 +++++++++++++++++++++++++++++++---
>>   1 file changed, 31 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
>> index 6c7fa08..4d5595b 100644
>> --- a/net/ipv6/addrconf.c
>> +++ b/net/ipv6/addrconf.c
>> @@ -2077,14 +2077,34 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>>   {
>>       u32 flags;
>>       struct inet6_ifaddr *ift;
>> +    unsigned long regen_advance;
>>
>>       read_lock_bh(&idev->lock);
>> +    regen_advance = idev->cnf.regen_max_retry *
>> +            idev->cnf.dad_transmits *
>> +            NEIGH_VAR(idev->nd_parms, RETRANS_TIME) / HZ;
>>       /* update all temporary addresses in the list */
>>       list_for_each_entry(ift, &idev->tempaddr_list, tmp_list) {
>>           int age, max_valid, max_prefered;
>> +        bool reparent;
>>
>> -        if (ifp != ift->ifpub)
>> -            continue;
>> +        reparent = false;
>
> You can collapse initialization where you declare the variable.
>
>> +        spin_lock(&ift->lock);
>> +        if (ifp != ift->ifpub) {
>> +            /* reparent if orphaned temporary address with same
>> +             * prefix is found
>> +             */
>> +            if (ipv6_prefix_equal(&ift->addr, &ifp->addr,
>> +                          ift->prefix_len)) {
>> +                in6_ifa_hold(ifp);
>> +                in6_ifa_put(ift->ifpub);
>> +                ift->ifpub = ifp;
>> +                reparent = true;
>> +            } else {
>> +                spin_unlock(&ift->lock);
>> +                continue;
>> +            }
>> +        }
>>
>>           /* RFC 4941 section 3.3:
>>            * If a received option will extend the lifetime of a public
>> @@ -2110,7 +2130,6 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>>           if (prefered_lft > max_prefered)
>>               prefered_lft = max_prefered;
>>
>> -        spin_lock(&ift->lock);
>>           flags = ift->flags;
>>           ift->valid_lft = valid_lft;
>>           ift->prefered_lft = prefered_lft;
>> @@ -2119,6 +2138,15 @@ static void manage_tempaddrs(struct inet6_dev *idev,
>>               ift->flags &= ~IFA_F_DEPRECATED;
>>
>>           spin_unlock(&ift->lock);
>> +        /* Don't create a temporary address if we reparented one which
>> +         * is prefered more than regen_advance
>
> Nit: s/prefered/preferred/
>
>> +         */
>> +        if (reparent && prefered_lft > regen_advance) {
>> +            create = false;
>> +            pr_info("%s: reparent orphaned temporary address\n",
>> +                __func__);
>
> The pr_info() should ideally be removed (or at least made pr_debug()).
>
>> +        }
>> +
>>           if (!(flags&IFA_F_TENTATIVE))
>>               ipv6_ifa_notify(0, ift);
>>       }
>>
>
Thanks for the hints, will send a revised patch.
Rgds, Heiner

^ permalink raw reply	[flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-04-07  5:43 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-04-06 19:04 [PATCH] ipv6: Reparent temporary address(es) if global address was deleted from userspace Heiner Kallweit
2014-04-06 20:27 ` Daniel Borkmann
2014-04-07  5:18   ` Heiner Kallweit

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