[PATCH net-next] net/hsr: add interlink to fill_info output

[PATCH net-next] net/hsr: add interlink to fill_info output

[Jan Vaclav]

Currently, it is possible to configure the interlink
port, but no way to read it back from userspace.

Add it to the output of hsr_fill_info(), so it can be
read from userspace, for example:

$ ip -d link show hsr0
12: hsr0: <BROADCAST,MULTICAST> mtu ...
...
hsr slave1 veth0 slave2 veth1 interlink veth2 ...

Signed-off-by: Jan Vaclav <jvaclav@redhat.com>
---
 net/hsr/hsr_netlink.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
index 4461adf69623..851187130755 100644
--- a/net/hsr/hsr_netlink.c
+++ b/net/hsr/hsr_netlink.c
@@ -160,6 +160,12 @@ static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
 			goto nla_put_failure;
 	}
 
+	port = hsr_port_get_hsr(hsr, HSR_PT_INTERLINK);
+	if (port) {
+		if (nla_put_u32(skb, IFLA_HSR_INTERLINK, port->dev->ifindex))
+			goto nla_put_failure;
+	}
+
 	if (nla_put(skb, IFLA_HSR_SUPERVISION_ADDR, ETH_ALEN,
 		    hsr->sup_multicast_addr) ||
 	    nla_put_u16(skb, IFLA_HSR_SEQ_NR, hsr->sequence_nr))
-- 
2.51.0

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[Fernando Fernandez Mancera]

On 10/15/25 12:10 PM, Jan Vaclav wrote:
> Currently, it is possible to configure the interlink
> port, but no way to read it back from userspace.
> 
> Add it to the output of hsr_fill_info(), so it can be
> read from userspace, for example:
> 
> $ ip -d link show hsr0
> 12: hsr0: <BROADCAST,MULTICAST> mtu ...
> ...
> hsr slave1 veth0 slave2 veth1 interlink veth2 ...
> 
> Signed-off-by: Jan Vaclav <jvaclav@redhat.com>
> ---
>   net/hsr/hsr_netlink.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
> index 4461adf69623..851187130755 100644
> --- a/net/hsr/hsr_netlink.c
> +++ b/net/hsr/hsr_netlink.c
> @@ -160,6 +160,12 @@ static int hsr_fill_info(struct sk_buff *skb, const struct net_device *dev)
>   			goto nla_put_failure;
>   	}
>   
> +	port = hsr_port_get_hsr(hsr, HSR_PT_INTERLINK);
> +	if (port) {
> +		if (nla_put_u32(skb, IFLA_HSR_INTERLINK, port->dev->ifindex))
> +			goto nla_put_failure;
> +	}
> +
>   	if (nla_put(skb, IFLA_HSR_SUPERVISION_ADDR, ETH_ALEN,
>   		    hsr->sup_multicast_addr) ||
>   	    nla_put_u16(skb, IFLA_HSR_SEQ_NR, hsr->sequence_nr))

Thank you Jan, it looks good to me.

Reviewed-by: Fernando Fernandez Mancera <fmancera@suse.de>

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[Jakub Kicinski]

On Wed, 15 Oct 2025 12:10:02 +0200 Jan Vaclav wrote:
> Currently, it is possible to configure the interlink
> port, but no way to read it back from userspace.
> 
> Add it to the output of hsr_fill_info(), so it can be
> read from userspace, for example:
> 
> $ ip -d link show hsr0
> 12: hsr0: <BROADCAST,MULTICAST> mtu ...
> ...
> hsr slave1 veth0 slave2 veth1 interlink veth2 ...

Not entirely cleat at a glance how this driver deals with the slaves or
interlink being in a different netns, but I guess that's a pre-existing
problem..

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[Fernando Fernandez Mancera]

On 10/17/25 12:57 AM, Jakub Kicinski wrote:
> On Wed, 15 Oct 2025 12:10:02 +0200 Jan Vaclav wrote:
>> Currently, it is possible to configure the interlink port, but no
>> way to read it back from userspace.
>> 
>> Add it to the output of hsr_fill_info(), so it can be read from
>> userspace, for example:
>> 
>> $ ip -d link show hsr0 12: hsr0: <BROADCAST,MULTICAST> mtu ... ... 
>> hsr slave1 veth0 slave2 veth1 interlink veth2 ...
> 
> Not entirely cleat at a glance how this driver deals with the slaves
> or interlink being in a different netns, but I guess that's a pre-
> existing problem..
> 

FTR, I just did a quick round of testing and it handles it correctly. 
When moving a port to a different netns it notifies NETDEV_UNREGISTER - 
net/hsr/hsr_main.c handles the notification removing the port from the 
list. If the port list is empty, removes the hsr link.

All good or at least as I would expect.

Thanks,
Fernando.

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[Jakub Kicinski]

On Fri, 17 Oct 2025 12:17:21 +0200 Fernando Fernandez Mancera wrote:
> On 10/17/25 12:57 AM, Jakub Kicinski wrote:
> > On Wed, 15 Oct 2025 12:10:02 +0200 Jan Vaclav wrote:  
> >> Currently, it is possible to configure the interlink port, but no
> >> way to read it back from userspace.
> >> 
> >> Add it to the output of hsr_fill_info(), so it can be read from
> >> userspace, for example:
> >> 
> >> $ ip -d link show hsr0 12: hsr0: <BROADCAST,MULTICAST> mtu ... ... 
> >> hsr slave1 veth0 slave2 veth1 interlink veth2 ...  
> > 
> > Not entirely cleat at a glance how this driver deals with the slaves
> > or interlink being in a different netns, but I guess that's a pre-
> > existing problem..
> >   
> 
> FTR, I just did a quick round of testing and it handles it correctly. 
> When moving a port to a different netns it notifies NETDEV_UNREGISTER - 
> net/hsr/hsr_main.c handles the notification removing the port from the 
> list. If the port list is empty, removes the hsr link.
> 
> All good or at least as I would expect.

Did you try to make the slave/interlink be in a different namespace
when HSR interface is created? It should be possible with the right
combination of NEWLINK attributes, and that's the config I was
particularly concerned about..

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[Fernando Fernandez Mancera]

On 10/18/25 12:17 AM, Jakub Kicinski wrote:
> On Fri, 17 Oct 2025 12:17:21 +0200 Fernando Fernandez Mancera wrote:
>> On 10/17/25 12:57 AM, Jakub Kicinski wrote:
>>> On Wed, 15 Oct 2025 12:10:02 +0200 Jan Vaclav wrote:
>>>> Currently, it is possible to configure the interlink port, but no
>>>> way to read it back from userspace.
>>>>
>>>> Add it to the output of hsr_fill_info(), so it can be read from
>>>> userspace, for example:
>>>>
>>>> $ ip -d link show hsr0 12: hsr0: <BROADCAST,MULTICAST> mtu ... ...
>>>> hsr slave1 veth0 slave2 veth1 interlink veth2 ...
>>>
>>> Not entirely cleat at a glance how this driver deals with the slaves
>>> or interlink being in a different netns, but I guess that's a pre-
>>> existing problem..
>>>    
>>
>> FTR, I just did a quick round of testing and it handles it correctly.
>> When moving a port to a different netns it notifies NETDEV_UNREGISTER -
>> net/hsr/hsr_main.c handles the notification removing the port from the
>> list. If the port list is empty, removes the hsr link.
>>
>> All good or at least as I would expect.
> 
> Did you try to make the slave/interlink be in a different namespace
> when HSR interface is created? It should be possible with the right
> combination of NEWLINK attributes, and that's the config I was
> particularly concerned about..
> 

Ugh, right. It is completely messed up indeed. I am handling this in a 
patch series. Thanks you Jakub.

Re: [PATCH net-next] net/hsr: add interlink to fill_info output

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 15 Oct 2025 12:10:02 +0200 you wrote:
> Currently, it is possible to configure the interlink
> port, but no way to read it back from userspace.
> 
> Add it to the output of hsr_fill_info(), so it can be
> read from userspace, for example:
> 
> $ ip -d link show hsr0
> 12: hsr0: <BROADCAST,MULTICAST> mtu ...
> ...
> hsr slave1 veth0 slave2 veth1 interlink veth2 ...
> 
> [...]

Here is the summary with links:
  - [net-next] net/hsr: add interlink to fill_info output
    https://git.kernel.org/netdev/net-next/c/f18c231fb12a

You are awesome, thank you!
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