This change allows userspace PM implementations to reissue ADD_ADDR
announcements (if necessary) based on their chosen policy.

Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
---
 net/mptcp/pm_netlink.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index d57e2f825728..1adaf5d14f87 100644
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -452,8 +452,16 @@ static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
 
 	lockdep_assert_held(&msk->pm.lock);
 
-	if (mptcp_lookup_anno_list_by_saddr(msk, &entry->addr))
-		return false;
+	add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
+
+	if (add_entry) {
+		if (READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL)
+			return false;
+
+		sk_reset_timer(sk, &add_entry->add_timer,
+			       jiffies + mptcp_get_add_addr_timeout(net));
+		return true;
+	}
 
 	add_entry = kmalloc(sizeof(*add_entry), GFP_ATOMIC);
 	if (!add_entry)
-- 
2.31.1

On Thu, 2021-12-16 at 17:23 -0500, Kishen Maloor wrote:
> This change allows userspace PM implementations to reissue ADD_ADDR
> announcements (if necessary) based on their chosen policy.
> 
> Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
> ---
>  net/mptcp/pm_netlink.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
> index d57e2f825728..1adaf5d14f87 100644
> --- a/net/mptcp/pm_netlink.c
> +++ b/net/mptcp/pm_netlink.c
> @@ -452,8 +452,16 @@ static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
>  
>  	lockdep_assert_held(&msk->pm.lock);
>  
> -	if (mptcp_lookup_anno_list_by_saddr(msk, &entry->addr))
> -		return false;
> +	add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
> +
> +	if (add_entry) {
> +		if (READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL)
> +			return false;
> +
> +		sk_reset_timer(sk, &add_entry->add_timer,
> +			       jiffies + mptcp_get_add_addr_timeout(net));
> +		return true;
> +	}

I'm unsure I understand correctly the goal here ?!? retransmission on
timeout of the announced address are already implmeneted by the
existing code. What kind of different behaviour do you want to obtain
here?

Thanks!

Paolo

On 12/17/21 10:38 AM, Paolo Abeni wrote:
> On Thu, 2021-12-16 at 17:23 -0500, Kishen Maloor wrote:
>> This change allows userspace PM implementations to reissue ADD_ADDR
>> announcements (if necessary) based on their chosen policy.
>>
>> Signed-off-by: Kishen Maloor <kishen.maloor@intel.com>
>> ---
>>  net/mptcp/pm_netlink.c | 12 ++++++++++--
>>  1 file changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
>> index d57e2f825728..1adaf5d14f87 100644
>> --- a/net/mptcp/pm_netlink.c
>> +++ b/net/mptcp/pm_netlink.c
>> @@ -452,8 +452,16 @@ static bool mptcp_pm_alloc_anno_list(struct mptcp_sock *msk,
>>  
>>  	lockdep_assert_held(&msk->pm.lock);
>>  
>> -	if (mptcp_lookup_anno_list_by_saddr(msk, &entry->addr))
>> -		return false;
>> +	add_entry = mptcp_lookup_anno_list_by_saddr(msk, &entry->addr);
>> +
>> +	if (add_entry) {
>> +		if (READ_ONCE(msk->pm.pm_type) == MPTCP_PM_TYPE_KERNEL)
>> +			return false;
>> +
>> +		sk_reset_timer(sk, &add_entry->add_timer,
>> +			       jiffies + mptcp_get_add_addr_timeout(net));
>> +		return true;
>> +	}
> 
> I'm unsure I understand correctly the goal here ?!? retransmission on
> timeout of the announced address are already implmeneted by the
> existing code. What kind of different behaviour do you want to obtain
> here?
> 

Yes, existing code retransmits unacknowledged ADD_ADDR messages.

This change is separate and allows userspace PMs to re-issue ADD_ADDR messages at a 
later time. Section 3.4.1 in RFC 8684 mentions scenarios where address advertisements
may be "refreshed" (periodically, or otherwise). The in-kernel PM has no such policy,
but this change allows userspace PMs to refresh ADD_ADDR information should they choose
to.

> Thanks!
> 
> Paolo
>