DP_GROUP_ID_BITS
return (drv_id << DP_GROUP_ID_BITS) | group_id;
return drv_group_id >> DP_GROUP_ID_BITS;
tunnel_group_drv_id(drv_group_id) & ((1 << DP_GROUP_ID_BITS) - 1),
tunnel_group_drv_id(drv_group_id) & ((1 << DP_GROUP_ID_BITS) - 1),
#define DP_GROUP_ID_MASK ((1 << DP_GROUP_ID_BITS) - 1)