dladm_stats_diff
dladm_stats_diff(&diff_stats, &stats, &state->ls_prevstats);
dladm_stats_diff(&state->gs_prevstats[i], &port_stat[i],
dladm_stats_diff(&diff_stats, vnic_stats, old_stats);
extern void dladm_stats_diff(pktsum_t *, pktsum_t *, pktsum_t *);