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* [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack
@ 2026-10-09 15:20 Gabriel Goller
  2026-10-13  6:14 ` Hangbin Liu
  2026-10-13 16:04 ` Andrea Mayer
  0 siblings, 2 replies; 3+ messages in thread
From: Gabriel Goller @ 2026-10-09 15:20 UTC (permalink / raw)
  To: Andrea Mayer, David S. Miller, Eric Dumazet, Jakub Kicinski,
	Paolo Abeni, Simon Horman
  Cc: netdev, linux-kernel

seg6_build_state() rejected invalid configurations with a generic -EINVAL,
so "ip route add ... encap seg6 ..." sometimes reported "Invalid argument".

Add extack messages to the checks that lacked one, and use
NL_REQ_ATTR_CHECK() for the missing SRH attribute so that userspace can
tell which attribute is missing. The checks themselves and their return
values are unchanged.

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---

v5 (https://lore.kernel.org/all/20261005140637.644840-1-g.goller@proxmox.com/):
 * use NL_REQ_ATTR_CHECK() for the missing SRH attribute (Jakub)
 * reword the inline mode message to "inline mode requires the IPv6
   address family", since it also applies to IPv4 nexthop objects
   (Andrea)
 * consistently call the header "IPv6 Segment Routing Header" (RFC 8754)
   in all messages (Andrea)
 * include the offending mode value in the invalid mode message
 * reword the commit message to match

v4 (https://lore.kernel.org/all/20260923120228.172643-1-g.goller@proxmox.com/):
 * use NL_SET_ERR_MSG when the SRH attr is missing
 * use NL_SET_ERR_MSG_ATTR when we have an invalid attr

v3 (https://lore.kernel.org/all/20260922090851.38978-1-g.goller@proxmox.com/):
 * format fix
 * use NL_SET_ERR_MSG_ATTR

v2 (https://lore.kernel.org/all/20260918153544.1178884-1-g.goller@proxmox.com/):
 * dropped tests

 net/ipv6/seg6_iptunnel.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
index 69a6ef5c5317..0d39a38a5dd2 100644
--- a/net/ipv6/seg6_iptunnel.c
+++ b/net/ipv6/seg6_iptunnel.c
@@ -762,8 +762,11 @@ 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);
@@ -771,7 +774,7 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
 	if (err < 0)
 		return err;
 
-	if (!tb[SEG6_IPTUNNEL_SRH])
+	if (NL_REQ_ATTR_CHECK(extack, nla, tb, SEG6_IPTUNNEL_SRH))
 		return -EINVAL;
 
 	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
@@ -782,13 +785,19 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
 	 */
 	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
 		   sizeof(struct in6_addr);
-	if (tuninfo_len < min_size)
+	if (tuninfo_len < min_size) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
+				    "truncated IPv6 Segment Routing Header attribute");
 		return -EINVAL;
+	}
 
 	switch (tuninfo->mode) {
 	case SEG6_IPTUN_MODE_INLINE:
-		if (family != AF_INET6)
+		if (family != AF_INET6) {
+			NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
+					    "inline mode requires the IPv6 address family");
 			return -EINVAL;
+		}
 
 		if (tb[SEG6_IPTUNNEL_SRC]) {
 			NL_SET_ERR_MSG(extack, "incompatible mode for tunsrc");
@@ -804,12 +813,19 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
 	case SEG6_IPTUN_MODE_L2ENCAP_RED:
 		break;
 	default:
+		NL_SET_ERR_MSG_ATTR_FMT(extack, tb[SEG6_IPTUNNEL_SRH],
+					"invalid SRv6 encapsulation mode %d",
+					tuninfo->mode);
 		return -EINVAL;
 	}
 
 	/* verify that SRH is consistent */
-	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
+	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo),
+			       false)) {
+		NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
+				    "invalid IPv6 Segment Routing Header");
 		return -EINVAL;
+	}
 
 	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
 	if (!newts)
-- 
2.47.3



^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack
  2026-10-09 15:20 [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack Gabriel Goller
@ 2026-10-13  6:14 ` Hangbin Liu
  2026-10-13 16:04 ` Andrea Mayer
  1 sibling, 0 replies; 3+ messages in thread
From: Hangbin Liu @ 2026-10-13  6:14 UTC (permalink / raw)
  To: Gabriel Goller
  Cc: Andrea Mayer, David S. Miller, Eric Dumazet, Jakub Kicinski,
	Paolo Abeni, Simon Horman, netdev, linux-kernel

Hi Gabriel,
On Fri, Oct 09, 2026 at 05:20:13PM +0200, Gabriel Goller wrote:
> seg6_build_state() rejected invalid configurations with a generic -EINVAL,
> so "ip route add ... encap seg6 ..." sometimes reported "Invalid argument".
> 
> Add extack messages to the checks that lacked one, and use
> NL_REQ_ATTR_CHECK() for the missing SRH attribute so that userspace can
> tell which attribute is missing. The checks themselves and their return
> values are unchanged.
> 
> Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
> ---
> 
> v5 (https://lore.kernel.org/all/20261005140637.644840-1-g.goller@proxmox.com/):
>  * use NL_REQ_ATTR_CHECK() for the missing SRH attribute (Jakub)
>  * reword the inline mode message to "inline mode requires the IPv6
>    address family", since it also applies to IPv4 nexthop objects
>    (Andrea)
>  * consistently call the header "IPv6 Segment Routing Header" (RFC 8754)
>    in all messages (Andrea)
>  * include the offending mode value in the invalid mode message
>  * reword the commit message to match
> 
> v4 (https://lore.kernel.org/all/20260923120228.172643-1-g.goller@proxmox.com/):
>  * use NL_SET_ERR_MSG when the SRH attr is missing
>  * use NL_SET_ERR_MSG_ATTR when we have an invalid attr
> 
> v3 (https://lore.kernel.org/all/20260922090851.38978-1-g.goller@proxmox.com/):
>  * format fix
>  * use NL_SET_ERR_MSG_ATTR
> 
> v2 (https://lore.kernel.org/all/20260918153544.1178884-1-g.goller@proxmox.com/):
>  * dropped tests
> 
>  net/ipv6/seg6_iptunnel.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c
> index 69a6ef5c5317..0d39a38a5dd2 100644
> --- a/net/ipv6/seg6_iptunnel.c
> +++ b/net/ipv6/seg6_iptunnel.c
> @@ -762,8 +762,11 @@ 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);
> @@ -771,7 +774,7 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
>  	if (err < 0)
>  		return err;
>  
> -	if (!tb[SEG6_IPTUNNEL_SRH])
> +	if (NL_REQ_ATTR_CHECK(extack, nla, tb, SEG6_IPTUNNEL_SRH))
>  		return -EINVAL;
>  
>  	tuninfo = nla_data(tb[SEG6_IPTUNNEL_SRH]);
> @@ -782,13 +785,19 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
>  	 */
>  	min_size = sizeof(*tuninfo) + sizeof(struct ipv6_sr_hdr) +
>  		   sizeof(struct in6_addr);
> -	if (tuninfo_len < min_size)
> +	if (tuninfo_len < min_size) {
> +		NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
> +				    "truncated IPv6 Segment Routing Header attribute");
>  		return -EINVAL;
> +	}
>  
>  	switch (tuninfo->mode) {
>  	case SEG6_IPTUN_MODE_INLINE:
> -		if (family != AF_INET6)
> +		if (family != AF_INET6) {
> +			NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
> +					    "inline mode requires the IPv6 address family");
>  			return -EINVAL;
> +		}
>  
>  		if (tb[SEG6_IPTUNNEL_SRC]) {
>  			NL_SET_ERR_MSG(extack, "incompatible mode for tunsrc");
> @@ -804,12 +813,19 @@ static int seg6_build_state(struct net *net, struct nlattr *nla,
>  	case SEG6_IPTUN_MODE_L2ENCAP_RED:
>  		break;
>  	default:
> +		NL_SET_ERR_MSG_ATTR_FMT(extack, tb[SEG6_IPTUNNEL_SRH],
> +					"invalid SRv6 encapsulation mode %d",
> +					tuninfo->mode);
>  		return -EINVAL;
>  	}
>  
>  	/* verify that SRH is consistent */
> -	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo), false))
> +	if (!seg6_validate_srh(tuninfo->srh, tuninfo_len - sizeof(*tuninfo),
> +			       false)) {
> +		NL_SET_ERR_MSG_ATTR(extack, tb[SEG6_IPTUNNEL_SRH],
> +				    "invalid IPv6 Segment Routing Header");
>  		return -EINVAL;
> +	}
>  
>  	newts = lwtunnel_state_alloc(tuninfo_len + sizeof(*slwt));
>  	if (!newts)
> -- 
> 2.47.3
> 
> 

Thanks for the update.

Reviewed-by: Hangbin Liu <liuhangbin@kylinos.cn>

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack
  2026-10-09 15:20 [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack Gabriel Goller
  2026-10-13  6:14 ` Hangbin Liu
@ 2026-10-13 16:04 ` Andrea Mayer
  1 sibling, 0 replies; 3+ messages in thread
From: Andrea Mayer @ 2026-10-13 16:04 UTC (permalink / raw)
  To: Gabriel Goller
  Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
	Simon Horman, netdev, linux-kernel, Hangbin Liu, stefano.salsano,
	Andrea Mayer

On Fri,  9 Oct 2026 17:20:13 +0200
Gabriel Goller <g.goller@proxmox.com> wrote:

Hi Gabriel,

thanks for the v5.

> seg6_build_state() rejected invalid configurations with a generic -EINVAL,
> so "ip route add ... encap seg6 ..." sometimes reported "Invalid argument".
> 
> Add extack messages to the checks that lacked one, and use
> NL_REQ_ATTR_CHECK() for the missing SRH attribute so that userspace can
> tell which attribute is missing. The checks themselves and their return
> values are unchanged.
> 
> Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
> ---
> 
> v5 (https://lore.kernel.org/all/20261005140637.644840-1-g.goller@proxmox.com/):
>  * use NL_REQ_ATTR_CHECK() for the missing SRH attribute (Jakub)
>  * reword the inline mode message to "inline mode requires the IPv6
>    address family", since it also applies to IPv4 nexthop objects
>    (Andrea)
>  * consistently call the header "IPv6 Segment Routing Header" (RFC 8754)
>    in all messages (Andrea)
>  * include the offending mode value in the invalid mode message
>  * reword the commit message to match
> 
> v4 (https://lore.kernel.org/all/20260923120228.172643-1-g.goller@proxmox.com/):
>  * use NL_SET_ERR_MSG when the SRH attr is missing
>  * use NL_SET_ERR_MSG_ATTR when we have an invalid attr
> 
> v3 (https://lore.kernel.org/all/20260922090851.38978-1-g.goller@proxmox.com/):
>  * format fix
>  * use NL_SET_ERR_MSG_ATTR
> 
> v2 (https://lore.kernel.org/all/20260918153544.1178884-1-g.goller@proxmox.com/):
>  * dropped tests
> 
>  net/ipv6/seg6_iptunnel.c | 26 +++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> [snip]
>  	default:
> +		NL_SET_ERR_MSG_ATTR_FMT(extack, tb[SEG6_IPTUNNEL_SRH],
> +					"invalid SRv6 encapsulation mode %d",
> +					tuninfo->mode);
>  		return -EINVAL;

A small nit on this one, as it is new in v5: I would have kept the
v4 text here, "invalid SRv6 encapsulation mode". No need for a new
version just for this.

Reviewed-by: Andrea Mayer <andrea.mayer@uniroma2.it>

Thanks,
Andrea

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2026-10-13 16:04 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2026-10-09 15:20 [PATCH net-next v5] net: ipv6: seg6: report lwtunnel setup errors via extack Gabriel Goller
2026-10-13  6:14 ` Hangbin Liu
2026-10-13 16:04 ` Andrea Mayer

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