tr = vlib_add_trace (vm, node, b, sizeof (*tr));
tr->next_index = next;
tr->sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];
tr = vlib_add_trace (vm, node, b, sizeof (*tr));
tr->next_index = next;
tr->sw_if_index = vnet_buffer (b)->sw_if_index[VLIB_RX];