On Thu, Oct 10, 2019 at 08:43:53PM +0200, Davide Caratti wrote:
> the following script:
>
> # tc qdisc add dev eth0 clsact
> # tc filter add dev eth0 egress protocol ip matchall \
> > action mpls push protocol mpls_uc label 0x355aa bos 1
>
> causes corruption of all IP packets transmitted by eth0. On TC egress, we
> can't rely on the value of skb->mac_len, because it's 0 and a MPLS 'push'
> operation will result in an overwrite of the first 4 octets in the packet
> L2 header (e.g. the Destination Address if eth0 is an Ethernet); the same
> error pattern is present also in the MPLS 'pop' operation. Fix this error
> in act_mpls data plane, computing 'mac_len' as the difference between the
> network header and the mac header (when not at TC ingress), and use it in
> MPLS 'push'/'pop' core functions.
>
> CC: Lorenzo Bianconi <lore...@kernel.org>
> Fixes: 2a2ea50870ba ("net: sched: add mpls manipulation actions to TC")
> Signed-off-by: Davide Caratti <dcara...@redhat.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
