[dpdk-dev] [RFC] net/mlx5: add GTP support

[Dekel Peled]

This RFC describes the update of MLX5 PMD, in order to support GTP tunnel type.
Update will include the support of matching on GTP item, fields msg_type and teid.

GTP item validation function flow_dv_validate_item_gtp() will be implemented. This function will:
Check that there is no tunnel layer in previous detected items. Multiple tunnel layers are not supported.
Check that GTP item is preceded by L3 item and L4 UDP item. GTP is supported over UDP only.
Check that there is no request to match on non-supported fields v_pt_rsv_flags and msg_len.
Matching will be supported only for fields msg_type and teid.

GTP item translation function flow_dv_translate_item_gtp() will be implemented.
This function will set GTP item fields in matcher.

Tunnel layer bit MLX5_FLOW_LAYER_GTP will be added, and updated in
MLX5_FLOW_LAYER_TUNNEL mask, tunnels_info[] array, and MLX5_FLOW_TUNNEL size.