Re: [PATCH net v2 2/2] selftest: net: Test IPv4 PMTU exceptions with DSCP and ECN

[David Ahern <dsahern@kernel.org>]

On 3/17/22 6:45 AM, Guillaume Nault wrote:
> Add two tests to pmtu.sh, for verifying that PMTU exceptions get
> properly created for routes that don't belong to the main table.
> 
> A fib-rule based on the packet's DSCP field is used to jump to the
> correct table. ECN shouldn't interfere with this process, so each test
> has two components: one that only sets DSCP and one that sets both DSCP
> and ECN.
> 
> One of the test triggers PMTU exceptions using ICMP Echo Requests, the
> other using UDP packets (to test different handlers in the kernel).
> 
> A few adjustments are necessary in the rest of the script to allow
> policy routing scenarios:
> 
>   * Add global variable rt_table that allows setup_routing_*() to
>     add routes to a specific routing table. By default rt_table is set
>     to "main", so existing tests don't need to be modified.
> 
>   * Another global variable, policy_mark, is used to define which
>     dsfield value is used for policy routing. This variable has no
>     effect on tests that don't use policy routing.
> 
>   * The UDP version of the test uses socat. So cleanup() now also need
>     to kill socat PIDs.
> 
>   * route_get_dst_pmtu_from_exception() and route_get_dst_exception()
>     now take an optional third argument specifying the dsfield. If
>     not specified, 0 is used, so existing users don't need to be
>     modified.
> 
> Signed-off-by: Guillaume Nault <gnault@redhat.com>
> ---
>  tools/testing/selftests/net/pmtu.sh | 141 +++++++++++++++++++++++++++-
>  1 file changed, 137 insertions(+), 4 deletions(-)
> 

Reviewed-by: David Ahern <dsahern@kernel.org>