Re: [PATCH net-next v2] net: ipv6: seg6: report lwtunnel setup errors via extack

[Gabriel Goller]

On 23.09.2026 09:29, Hangbin Liu wrote:
> On Tue, Sep 22, 2026 at 11:08:33AM +0200, Gabriel Goller wrote:
> > seg6_build_state() rejected invalid configurations with a generic -EINVAL, so
> > "ip route add ... encap seg6 ..." always reported "Invalid argument".
> > 
> > Attach an extack message to each of them. The checks themselves and their return
> > values are unchanged.
> > 
> > Signed-off-by: Gabriel Goller <g.goller@xxxxxxxxxxx>
> > ---
> > 
> > v2 (https://lore.kernel.org/netdev/20260918153544.1178884-1-g.goller@xxxxxxxxxxx/):
> >  * dropped tests
> > 
> >  net/ipv6/seg6_iptunnel.c | 25 ++++++++++++++++++++-----
> >  1 file changed, 20 insertions(+), 5 deletions(-)
> > 
> > diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
> > index 61c6a27bf202..e7f75970e26e 100644
> > --- a/net/ipv6/seg6_iptunnel.c
> > +++ b/net/ipv6/seg6_iptunnel.c
> > @@ -756,8 +756,12 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
> >  	struct seg6_lwt *slwt;
> >  	int err;
> >  
> > -	if (family != AF_INET && family != AF_INET6)
> > +	if (family != AF_INET && family != AF_INET6) {
> > +		NL_SET_ERR_MSG(
> > +			extack,
> > +			"unsupported address family for SRv6 encapsulation");
> >  		return -EINVAL;
> > +	}
> >  
> >  	err = nla_parse_nested_deprecated(tb, SEG6_IPTUNNEL_MAX, nla,
> >  					  seg6_iptunnel_policy, extack);
> > @@ -765,8 +769,10 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
> >  	if (err < 0)
> >  		return err;
> >  
> > -	if (!tb[SEG6_IPTUNNEL_SRH])
> > +	if (!tb[SEG6_IPTUNNEL_SRH]) {
> > +		NL_SET_ERR_MSG(extack, "missing SRv6 SRH attribute");
> 
> I think we can use NL_SET_ERR_MSG_ATTR.

Done, thanks!

Gabriel

> 
> Thanks
> Hangbin
> 
>