vlib_set_trace_count (vm, node, --n_trace);
t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
t0->sw_if_index = sw_if_index0;
vlib_set_trace_count (vm, node, --n_trace);
t0 = vlib_add_trace (vm, node, b0, sizeof (*t0));
t0->sw_if_index = sw_if_index0;