[PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[Ricardo B. Marlière]

Currently, the test breaks if the SUT already has a default route
configured for IPv6. Fix by adding "metric 9999" to the `ip -6 ro add`
command, so that multiple default routes can coexist.

Fixes: 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route")
Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/net/fib-onlink-tests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/fib-onlink-tests.sh b/tools/testing/selftests/net/fib-onlink-tests.sh
index ec2d6ceb1f08..acf6b0617373 100755
--- a/tools/testing/selftests/net/fib-onlink-tests.sh
+++ b/tools/testing/selftests/net/fib-onlink-tests.sh
@@ -207,7 +207,7 @@ setup()
 		ip -netns ${PEER_NS} addr add ${V6ADDRS[p${n}]}/64 dev ${NETIFS[p${n}]} nodad
 	done
 
-	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64}
+	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64} metric 9999
 	ip -6 ro add table ${VRF_TABLE} default via ${V6ADDRS[p7]/::[0-9]/::64}
 
 	set +e

---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251218-rbm-selftests-net-fib-onlink-873ad01e6884

Best regards,
-- 
Ricardo B. Marlière <rbm@suse.com>

Re: [PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[David Ahern]

On 12/18/25 5:20 AM, Ricardo B. Marlière wrote:
> Currently, the test breaks if the SUT already has a default route
> configured for IPv6. Fix by adding "metric 9999" to the `ip -6 ro add`
> command, so that multiple default routes can coexist.
> 
> Fixes: 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route")
> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
> ---
>  tools/testing/selftests/net/fib-onlink-tests.sh | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/net/fib-onlink-tests.sh b/tools/testing/selftests/net/fib-onlink-tests.sh
> index ec2d6ceb1f08..acf6b0617373 100755
> --- a/tools/testing/selftests/net/fib-onlink-tests.sh
> +++ b/tools/testing/selftests/net/fib-onlink-tests.sh
> @@ -207,7 +207,7 @@ setup()
>  		ip -netns ${PEER_NS} addr add ${V6ADDRS[p${n}]}/64 dev ${NETIFS[p${n}]} nodad
>  	done
>  
> -	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64}
> +	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64} metric 9999
>  	ip -6 ro add table ${VRF_TABLE} default via ${V6ADDRS[p7]/::[0-9]/::64}
>  
>  	set +e
> 
> ---
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
> change-id: 20251218-rbm-selftests-net-fib-onlink-873ad01e6884
> 
> Best regards,

The intent of selftests is to run them in a clean environment with known
settings. ie, there should not be a conflicting default route.

Re: [PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[Fernando Fernandez Mancera]

On 12/18/25 1:20 PM, Ricardo B. Marlière wrote:
> Currently, the test breaks if the SUT already has a default route
> configured for IPv6. Fix by adding "metric 9999" to the `ip -6 ro add`
> command, so that multiple default routes can coexist.
> 
> Fixes: 4ed591c8ab44 ("net/ipv6: Allow onlink routes to have a device mismatch if it is the default route")
> Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
> ---
>   tools/testing/selftests/net/fib-onlink-tests.sh | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/net/fib-onlink-tests.sh b/tools/testing/selftests/net/fib-onlink-tests.sh
> index ec2d6ceb1f08..acf6b0617373 100755
> --- a/tools/testing/selftests/net/fib-onlink-tests.sh
> +++ b/tools/testing/selftests/net/fib-onlink-tests.sh
> @@ -207,7 +207,7 @@ setup()
>   		ip -netns ${PEER_NS} addr add ${V6ADDRS[p${n}]}/64 dev ${NETIFS[p${n}]} nodad
>   	done
>   
> -	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64}
> +	ip -6 ro add default via ${V6ADDRS[p3]/::[0-9]/::64} metric 9999
>   	ip -6 ro add table ${VRF_TABLE} default via ${V6ADDRS[p7]/::[0-9]/::64}
> 

It would probably require some work on the test but I think it could 
benefit from using two different network namespaces. Currently it is 
using PEER_NS and the default. I think avoiding the default one is 
beneficial for everyone as it ensures the state is clean and that the 
test won't interrupt the system connectivity.

Other tests already do that, e.g some tests in fib_tests.sh use ns1 and 
ns2 namespaces.

What do you all think?

>   	set +e
> 
> ---
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
> change-id: 20251218-rbm-selftests-net-fib-onlink-873ad01e6884
> 
> Best regards,

Re: [PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[David Ahern]

On 12/19/25 7:51 AM, Fernando Fernandez Mancera wrote:
> It would probably require some work on the test but I think it could
> benefit from using two different network namespaces. Currently it is
> using PEER_NS and the default. I think avoiding the default one is
> beneficial for everyone as it ensures the state is clean and that the
> test won't interrupt the system connectivity.
> 
> Other tests already do that, e.g some tests in fib_tests.sh use ns1 and
> ns2 namespaces.
> 
> What do you all think?

agreed.

Re: [PATCH] selftests: net: fib-onlink-tests: Set high metric for default IPv6 route

[Ricardo B. Marlière]

On Fri Dec 19, 2025 at 12:51 PM -03, David Ahern wrote:
> On 12/19/25 7:51 AM, Fernando Fernandez Mancera wrote:
>> It would probably require some work on the test but I think it could
>> benefit from using two different network namespaces. Currently it is
>> using PEER_NS and the default. I think avoiding the default one is
>> beneficial for everyone as it ensures the state is clean and that the
>> test won't interrupt the system connectivity.
>> 
>> Other tests already do that, e.g some tests in fib_tests.sh use ns1 and
>> ns2 namespaces.
>> 
>> What do you all think?
>
> agreed.

Thanks, I'll send a new version later on this week then!